fs/btrfs/inode.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/kernel.h>
  20 #include <linux/bio.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/file.h>
  23 #include <linux/fs.h>
  24 #include <linux/pagemap.h>
  25 #include <linux/highmem.h>
  26 #include <linux/time.h>
  27 #include <linux/init.h>
  28 #include <linux/string.h>
  29 #include <linux/backing-dev.h>
  30 #include <linux/mpage.h>
  31 #include <linux/swap.h>
  32 #include <linux/writeback.h>
  33 #include <linux/statfs.h>
  34 #include <linux/compat.h>
  35 #include <linux/aio.h>
  36 #include <linux/bit_spinlock.h>
  37 #include <linux/xattr.h>
  38 #include <linux/posix_acl.h>
  39 #include <linux/falloc.h>
  40 #include <linux/slab.h>
  41 #include <linux/ratelimit.h>
  42 #include <linux/mount.h>
  43 #include <linux/btrfs.h>
  44 #include <linux/blkdev.h>
  45 #include <linux/posix_acl_xattr.h>
  46 #include "ctree.h"
  47 #include "disk-io.h"
  48 #include "transaction.h"
  49 #include "btrfs_inode.h"
  50 #include "print-tree.h"
  51 #include "ordered-data.h"
  52 #include "xattr.h"
  53 #include "tree-log.h"
  54 #include "volumes.h"
  55 #include "compression.h"
  56 #include "locking.h"
  57 #include "free-space-cache.h"
  58 #include "inode-map.h"
  59 #include "backref.h"
  60 #include "hash.h"
  61 #include "props.h"
  62
  63 struct btrfs_iget_args {
  64         struct btrfs_key *location;
  65         struct btrfs_root *root;
  66 };
  67
  68 static const struct inode_operations btrfs_dir_inode_operations;
  69 static const struct inode_operations btrfs_symlink_inode_operations;
  70 static const struct inode_operations btrfs_dir_ro_inode_operations;
  71 static const struct inode_operations btrfs_special_inode_operations;
  72 static const struct inode_operations btrfs_file_inode_operations;
  73 static const struct address_space_operations btrfs_aops;
  74 static const struct address_space_operations btrfs_symlink_aops;
  75 static const struct file_operations btrfs_dir_file_operations;
  76 static struct extent_io_ops btrfs_extent_io_ops;
  77
  78 static struct kmem_cache *btrfs_inode_cachep;
  79 static struct kmem_cache *btrfs_delalloc_work_cachep;
  80 struct kmem_cache *btrfs_trans_handle_cachep;
  81 struct kmem_cache *btrfs_transaction_cachep;
  82 struct kmem_cache *btrfs_path_cachep;
  83 struct kmem_cache *btrfs_free_space_cachep;
  84
  85 #define S_SHIFT 12
  86 static unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
  87         [S_IFREG >> S_SHIFT]    = BTRFS_FT_REG_FILE,
  88         [S_IFDIR >> S_SHIFT]    = BTRFS_FT_DIR,
  89         [S_IFCHR >> S_SHIFT]    = BTRFS_FT_CHRDEV,
  90         [S_IFBLK >> S_SHIFT]    = BTRFS_FT_BLKDEV,
  91         [S_IFIFO >> S_SHIFT]    = BTRFS_FT_FIFO,
  92         [S_IFSOCK >> S_SHIFT]   = BTRFS_FT_SOCK,
  93         [S_IFLNK >> S_SHIFT]    = BTRFS_FT_SYMLINK,
  94 };
  95
  96 static int btrfs_setsize(struct inode *inode, struct iattr *attr);
  97 static int btrfs_truncate(struct inode *inode);
  98 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent);
  99 static noinline int cow_file_range(struct inode *inode,
 100                                    struct page *locked_page,
 101                                    u64 start, u64 end, int *page_started,
 102                                    unsigned long *nr_written, int unlock);
 103 static struct extent_map *create_pinned_em(struct inode *inode, u64 start,
 104                                            u64 len, u64 orig_start,
 105                                            u64 block_start, u64 block_len,
 106                                            u64 orig_block_len, u64 ram_bytes,
 107                                            int type);
 108
 109 static int btrfs_dirty_inode(struct inode *inode);
 110
 111 static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
 112                                      struct inode *inode,  struct inode *dir,
 113                                      const struct qstr *qstr)
 114 {
 115         int err;
 116
 117         err = btrfs_init_acl(trans, inode, dir);
 118         if (!err)
 119                 err = btrfs_xattr_security_init(trans, inode, dir, qstr);
 120         return err;
 121 }
 122
 123 /*
 124  * this does all the hard work for inserting an inline extent into
 125  * the btree.  The caller should have done a btrfs_drop_extents so that
 126  * no overlapping inline items exist in the btree
 127  */
 128 static int insert_inline_extent(struct btrfs_trans_handle *trans,
 129                                 struct btrfs_path *path, int extent_inserted,
 130                                 struct btrfs_root *root, struct inode *inode,
 131                                 u64 start, size_t size, size_t compressed_size,
 132                                 int compress_type,
 133                                 struct page **compressed_pages)
 134 {
 135         struct extent_buffer *leaf;
 136         struct page *page = NULL;
 137         char *kaddr;
 138         unsigned long ptr;
 139         struct btrfs_file_extent_item *ei;
 140         int err = 0;
 141         int ret;
 142         size_t cur_size = size;
 143         unsigned long offset;
 144
 145         if (compressed_size && compressed_pages)
 146                 cur_size = compressed_size;
 147
 148         inode_add_bytes(inode, size);
 149
 150         if (!extent_inserted) {
 151                 struct btrfs_key key;
 152                 size_t datasize;
 153
 154                 key.objectid = btrfs_ino(inode);
 155                 key.offset = start;
 156                 key.type = BTRFS_EXTENT_DATA_KEY;
 157
 158                 datasize = btrfs_file_extent_calc_inline_size(cur_size);
 159                 path->leave_spinning = 1;
 160                 ret = btrfs_insert_empty_item(trans, root, path, &key,
 161                                               datasize);
 162                 if (ret) {
 163                         err = ret;
 164                         goto fail;
 165                 }
 166         }
 167         leaf = path->nodes[0];
 168         ei = btrfs_item_ptr(leaf, path->slots[0],
 169                             struct btrfs_file_extent_item);
 170         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
 171         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
 172         btrfs_set_file_extent_encryption(leaf, ei, 0);
 173         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
 174         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
 175         ptr = btrfs_file_extent_inline_start(ei);
 176
 177         if (compress_type != BTRFS_COMPRESS_NONE) {
 178                 struct page *cpage;
 179                 int i = 0;
 180                 while (compressed_size > 0) {
 181                         cpage = compressed_pages[i];
 182                         cur_size = min_t(unsigned long, compressed_size,
 183                                        PAGE_CACHE_SIZE);
 184
 185                         kaddr = kmap_atomic(cpage);
 186                         write_extent_buffer(leaf, kaddr, ptr, cur_size);
 187                         kunmap_atomic(kaddr);
 188
 189                         i++;
 190                         ptr += cur_size;
 191                         compressed_size -= cur_size;
 192                 }
 193                 btrfs_set_file_extent_compression(leaf, ei,
 194                                                   compress_type);
 195         } else {
 196                 page = find_get_page(inode->i_mapping,
 197                                      start >> PAGE_CACHE_SHIFT);
 198                 btrfs_set_file_extent_compression(leaf, ei, 0);
 199                 kaddr = kmap_atomic(page);
 200                 offset = start & (PAGE_CACHE_SIZE - 1);
 201                 write_extent_buffer(leaf, kaddr + offset, ptr, size);
 202                 kunmap_atomic(kaddr);
 203                 page_cache_release(page);
 204         }
 205         btrfs_mark_buffer_dirty(leaf);
 206         btrfs_release_path(path);
 207
 208         /*
 209          * we're an inline extent, so nobody can
 210          * extend the file past i_size without locking
 211          * a page we already have locked.
 212          *
 213          * We must do any isize and inode updates
 214          * before we unlock the pages.  Otherwise we
 215          * could end up racing with unlink.
 216          */
 217         BTRFS_I(inode)->disk_i_size = inode->i_size;
 218         ret = btrfs_update_inode(trans, root, inode);
 219
 220         return ret;
 221 fail:
 222         return err;
 223 }
 224
 225
 226 /*
 227  * conditionally insert an inline extent into the file.  This
 228  * does the checks required to make sure the data is small enough
 229  * to fit as an inline extent.
 230  */
 231 static noinline int cow_file_range_inline(struct btrfs_root *root,
 232                                           struct inode *inode, u64 start,
 233                                           u64 end, size_t compressed_size,
 234                                           int compress_type,
 235                                           struct page **compressed_pages)
 236 {
 237         struct btrfs_trans_handle *trans;
 238         u64 isize = i_size_read(inode);
 239         u64 actual_end = min(end + 1, isize);
 240         u64 inline_len = actual_end - start;
 241         u64 aligned_end = ALIGN(end, root->sectorsize);
 242         u64 data_len = inline_len;
 243         int ret;
 244         struct btrfs_path *path;
 245         int extent_inserted = 0;
 246         u32 extent_item_size;
 247
 248         if (compressed_size)
 249                 data_len = compressed_size;
 250
 251         if (start > 0 ||
 252             actual_end > PAGE_CACHE_SIZE ||
 253             data_len > BTRFS_MAX_INLINE_DATA_SIZE(root) ||
 254             (!compressed_size &&
 255             (actual_end & (root->sectorsize - 1)) == 0) ||
 256             end + 1 < isize ||
 257             data_len > root->fs_info->max_inline) {
 258                 return 1;
 259         }
 260
 261         path = btrfs_alloc_path();
 262         if (!path)
 263                 return -ENOMEM;
 264
 265         trans = btrfs_join_transaction(root);
 266         if (IS_ERR(trans)) {
 267                 btrfs_free_path(path);
 268                 return PTR_ERR(trans);
 269         }
 270         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
 271
 272         if (compressed_size && compressed_pages)
 273                 extent_item_size = btrfs_file_extent_calc_inline_size(
 274                    compressed_size);
 275         else
 276                 extent_item_size = btrfs_file_extent_calc_inline_size(
 277                     inline_len);
 278
 279         ret = __btrfs_drop_extents(trans, root, inode, path,
 280                                    start, aligned_end, NULL,
 281                                    1, 1, extent_item_size, &extent_inserted);
 282         if (ret) {
 283                 btrfs_abort_transaction(trans, root, ret);
 284                 goto out;
 285         }
 286
 287         if (isize > actual_end)
 288                 inline_len = min_t(u64, isize, actual_end);
 289         ret = insert_inline_extent(trans, path, extent_inserted,
 290                                    root, inode, start,
 291                                    inline_len, compressed_size,
 292                                    compress_type, compressed_pages);
 293         if (ret && ret != -ENOSPC) {
 294                 btrfs_abort_transaction(trans, root, ret);
 295                 goto out;
 296         } else if (ret == -ENOSPC) {
 297                 ret = 1;
 298                 goto out;
 299         }
 300
 301         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
 302         btrfs_delalloc_release_metadata(inode, end + 1 - start);
 303         btrfs_drop_extent_cache(inode, start, aligned_end - 1, 0);
 304 out:
 305         btrfs_free_path(path);
 306         btrfs_end_transaction(trans, root);
 307         return ret;
 308 }
 309
 310 struct async_extent {
 311         u64 start;
 312         u64 ram_size;
 313         u64 compressed_size;
 314         struct page **pages;
 315         unsigned long nr_pages;
 316         int compress_type;
 317         struct list_head list;
 318 };
 319
 320 struct async_cow {
 321         struct inode *inode;
 322         struct btrfs_root *root;
 323         struct page *locked_page;
 324         u64 start;
 325         u64 end;
 326         struct list_head extents;
 327         struct btrfs_work work;
 328 };
 329
 330 static noinline int add_async_extent(struct async_cow *cow,
 331                                      u64 start, u64 ram_size,
 332                                      u64 compressed_size,
 333                                      struct page **pages,
 334                                      unsigned long nr_pages,
 335                                      int compress_type)
 336 {
 337         struct async_extent *async_extent;
 338
 339         async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
 340         BUG_ON(!async_extent); /* -ENOMEM */
 341         async_extent->start = start;
 342         async_extent->ram_size = ram_size;
 343         async_extent->compressed_size = compressed_size;
 344         async_extent->pages = pages;
 345         async_extent->nr_pages = nr_pages;
 346         async_extent->compress_type = compress_type;
 347         list_add_tail(&async_extent->list, &cow->extents);
 348         return 0;
 349 }
 350
 351 static inline int inode_need_compress(struct inode *inode)
 352 {
 353         struct btrfs_root *root = BTRFS_I(inode)->root;
 354
 355         /* force compress */
 356         if (btrfs_test_opt(root, FORCE_COMPRESS))
 357                 return 1;
 358         /* bad compression ratios */
 359         if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
 360                 return 0;
 361         if (btrfs_test_opt(root, COMPRESS) ||
 362             BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS ||
 363             BTRFS_I(inode)->force_compress)
 364                 return 1;
 365         return 0;
 366 }
 367
 368 /*
 369  * we create compressed extents in two phases.  The first
 370  * phase compresses a range of pages that have already been
 371  * locked (both pages and state bits are locked).
 372  *
 373  * This is done inside an ordered work queue, and the compression
 374  * is spread across many cpus.  The actual IO submission is step
 375  * two, and the ordered work queue takes care of making sure that
 376  * happens in the same order things were put onto the queue by
 377  * writepages and friends.
 378  *
 379  * If this code finds it can't get good compression, it puts an
 380  * entry onto the work queue to write the uncompressed bytes.  This
 381  * makes sure that both compressed inodes and uncompressed inodes
 382  * are written in the same order that the flusher thread sent them
 383  * down.
 384  */
 385 static noinline int compress_file_range(struct inode *inode,
 386                                         struct page *locked_page,
 387                                         u64 start, u64 end,
 388                                         struct async_cow *async_cow,
 389                                         int *num_added)
 390 {
 391         struct btrfs_root *root = BTRFS_I(inode)->root;
 392         u64 num_bytes;
 393         u64 blocksize = root->sectorsize;
 394         u64 actual_end;
 395         u64 isize = i_size_read(inode);
 396         int ret = 0;
 397         struct page **pages = NULL;
 398         unsigned long nr_pages;
 399         unsigned long nr_pages_ret = 0;
 400         unsigned long total_compressed = 0;
 401         unsigned long total_in = 0;
 402         unsigned long max_compressed = 128 * 1024;
 403         unsigned long max_uncompressed = 128 * 1024;
 404         int i;
 405         int will_compress;
 406         int compress_type = root->fs_info->compress_type;
 407         int redirty = 0;
 408
 409         /* if this is a small write inside eof, kick off a defrag */
 410         if ((end - start + 1) < 16 * 1024 &&
 411             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 412                 btrfs_add_inode_defrag(NULL, inode);
 413
 414         actual_end = min_t(u64, isize, end + 1);
 415 again:
 416         will_compress = 0;
 417         nr_pages = (end >> PAGE_CACHE_SHIFT) - (start >> PAGE_CACHE_SHIFT) + 1;
 418         nr_pages = min(nr_pages, (128 * 1024UL) / PAGE_CACHE_SIZE);
 419
 420         /*
 421          * we don't want to send crud past the end of i_size through
 422          * compression, that's just a waste of CPU time.  So, if the
 423          * end of the file is before the start of our current
 424          * requested range of bytes, we bail out to the uncompressed
 425          * cleanup code that can deal with all of this.
 426          *
 427          * It isn't really the fastest way to fix things, but this is a
 428          * very uncommon corner.
 429          */
 430         if (actual_end <= start)
 431                 goto cleanup_and_bail_uncompressed;
 432
 433         total_compressed = actual_end - start;
 434
 435         /*
 436          * skip compression for a small file range(<=blocksize) that
 437          * isn't an inline extent, since it dosen't save disk space at all.
 438          */
 439         if (total_compressed <= blocksize &&
 440            (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 441                 goto cleanup_and_bail_uncompressed;
 442
 443         /* we want to make sure that amount of ram required to uncompress
 444          * an extent is reasonable, so we limit the total size in ram
 445          * of a compressed extent to 128k.  This is a crucial number
 446          * because it also controls how easily we can spread reads across
 447          * cpus for decompression.
 448          *
 449          * We also want to make sure the amount of IO required to do
 450          * a random read is reasonably small, so we limit the size of
 451          * a compressed extent to 128k.
 452          */
 453         total_compressed = min(total_compressed, max_uncompressed);
 454         num_bytes = ALIGN(end - start + 1, blocksize);
 455         num_bytes = max(blocksize,  num_bytes);
 456         total_in = 0;
 457         ret = 0;
 458
 459         /*
 460          * we do compression for mount -o compress and when the
 461          * inode has not been flagged as nocompress.  This flag can
 462          * change at any time if we discover bad compression ratios.
 463          */
 464         if (inode_need_compress(inode)) {
 465                 WARN_ON(pages);
 466                 pages = kzalloc(sizeof(struct page *) * nr_pages, GFP_NOFS);
 467                 if (!pages) {
 468                         /* just bail out to the uncompressed code */
 469                         goto cont;
 470                 }
 471
 472                 if (BTRFS_I(inode)->force_compress)
 473                         compress_type = BTRFS_I(inode)->force_compress;
 474
 475                 /*
 476                  * we need to call clear_page_dirty_for_io on each
 477                  * page in the range.  Otherwise applications with the file
 478                  * mmap'd can wander in and change the page contents while
 479                  * we are compressing them.
 480                  *
 481                  * If the compression fails for any reason, we set the pages
 482                  * dirty again later on.
 483                  */
 484                 extent_range_clear_dirty_for_io(inode, start, end);
 485                 redirty = 1;
 486                 ret = btrfs_compress_pages(compress_type,
 487                                            inode->i_mapping, start,
 488                                            total_compressed, pages,
 489                                            nr_pages, &nr_pages_ret,
 490                                            &total_in,
 491                                            &total_compressed,
 492                                            max_compressed);
 493
 494                 if (!ret) {
 495                         unsigned long offset = total_compressed &
 496                                 (PAGE_CACHE_SIZE - 1);
 497                         struct page *page = pages[nr_pages_ret - 1];
 498                         char *kaddr;
 499
 500                         /* zero the tail end of the last page, we might be
 501                          * sending it down to disk
 502                          */
 503                         if (offset) {
 504                                 kaddr = kmap_atomic(page);
 505                                 memset(kaddr + offset, 0,
 506                                        PAGE_CACHE_SIZE - offset);
 507                                 kunmap_atomic(kaddr);
 508                         }
 509                         will_compress = 1;
 510                 }
 511         }
 512 cont:
 513         if (start == 0) {
 514                 /* lets try to make an inline extent */
 515                 if (ret || total_in < (actual_end - start)) {
 516                         /* we didn't compress the entire range, try
 517                          * to make an uncompressed inline extent.
 518                          */
 519                         ret = cow_file_range_inline(root, inode, start, end,
 520                                                     0, 0, NULL);
 521                 } else {
 522                         /* try making a compressed inline extent */
 523                         ret = cow_file_range_inline(root, inode, start, end,
 524                                                     total_compressed,
 525                                                     compress_type, pages);
 526                 }
 527                 if (ret <= 0) {
 528                         unsigned long clear_flags = EXTENT_DELALLOC |
 529                                 EXTENT_DEFRAG;
 530                         clear_flags |= (ret < 0) ? EXTENT_DO_ACCOUNTING : 0;
 531
 532                         /*
 533                          * inline extent creation worked or returned error,
 534                          * we don't need to create any more async work items.
 535                          * Unlock and free up our temp pages.
 536                          */
 537                         extent_clear_unlock_delalloc(inode, start, end, NULL,
 538                                                      clear_flags, PAGE_UNLOCK |
 539                                                      PAGE_CLEAR_DIRTY |
 540                                                      PAGE_SET_WRITEBACK |
 541                                                      PAGE_END_WRITEBACK);
 542                         goto free_pages_out;
 543                 }
 544         }
 545
 546         if (will_compress) {
 547                 /*
 548                  * we aren't doing an inline extent round the compressed size
 549                  * up to a block size boundary so the allocator does sane
 550                  * things
 551                  */
 552                 total_compressed = ALIGN(total_compressed, blocksize);
 553
 554                 /*
 555                  * one last check to make sure the compression is really a
 556                  * win, compare the page count read with the blocks on disk
 557                  */
 558                 total_in = ALIGN(total_in, PAGE_CACHE_SIZE);
 559                 if (total_compressed >= total_in) {
 560                         will_compress = 0;
 561                 } else {
 562                         num_bytes = total_in;
 563                 }
 564         }
 565         if (!will_compress && pages) {
 566                 /*
 567                  * the compression code ran but failed to make things smaller,
 568                  * free any pages it allocated and our page pointer array
 569                  */
 570                 for (i = 0; i < nr_pages_ret; i++) {
 571                         WARN_ON(pages[i]->mapping);
 572                         page_cache_release(pages[i]);
 573                 }
 574                 kfree(pages);
 575                 pages = NULL;
 576                 total_compressed = 0;
 577                 nr_pages_ret = 0;
 578
 579                 /* flag the file so we don't compress in the future */
 580                 if (!btrfs_test_opt(root, FORCE_COMPRESS) &&
 581                     !(BTRFS_I(inode)->force_compress)) {
 582                         BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
 583                 }
 584         }
 585         if (will_compress) {
 586                 *num_added += 1;
 587
 588                 /* the async work queues will take care of doing actual
 589                  * allocation on disk for these compressed pages,
 590                  * and will submit them to the elevator.
 591                  */
 592                 add_async_extent(async_cow, start, num_bytes,
 593                                  total_compressed, pages, nr_pages_ret,
 594                                  compress_type);
 595
 596                 if (start + num_bytes < end) {
 597                         start += num_bytes;
 598                         pages = NULL;
 599                         cond_resched();
 600                         goto again;
 601                 }
 602         } else {
 603 cleanup_and_bail_uncompressed:
 604                 /*
 605                  * No compression, but we still need to write the pages in
 606                  * the file we've been given so far.  redirty the locked
 607                  * page if it corresponds to our extent and set things up
 608                  * for the async work queue to run cow_file_range to do
 609                  * the normal delalloc dance
 610                  */
 611                 if (page_offset(locked_page) >= start &&
 612                     page_offset(locked_page) <= end) {
 613                         __set_page_dirty_nobuffers(locked_page);
 614                         /* unlocked later on in the async handlers */
 615                 }
 616                 if (redirty)
 617                         extent_range_redirty_for_io(inode, start, end);
 618                 add_async_extent(async_cow, start, end - start + 1,
 619                                  0, NULL, 0, BTRFS_COMPRESS_NONE);
 620                 *num_added += 1;
 621         }
 622
 623 out:
 624         return ret;
 625
 626 free_pages_out:
 627         for (i = 0; i < nr_pages_ret; i++) {
 628                 WARN_ON(pages[i]->mapping);
 629                 page_cache_release(pages[i]);
 630         }
 631         kfree(pages);
 632
 633         goto out;
 634 }
 635
 636 static void free_async_extent_pages(struct async_extent *async_extent)
 637 {
 638         int i;
 639
 640         if (!async_extent->pages)
 641                 return;
 642
 643         for (i = 0; i < async_extent->nr_pages; i++) {
 644                 WARN_ON(async_extent->pages[i]->mapping);
 645                 page_cache_release(async_extent->pages[i]);
 646         }
 647         kfree(async_extent->pages);
 648         async_extent->nr_pages = 0;
 649         async_extent->pages = NULL;
 650 }
 651
 652 /*
 653  * phase two of compressed writeback.  This is the ordered portion
 654  * of the code, which only gets called in the order the work was
 655  * queued.  We walk all the async extents created by compress_file_range
 656  * and send them down to the disk.
 657  */
 658 static noinline void submit_compressed_extents(struct inode *inode,
 659                                               struct async_cow *async_cow)
 660 {
 661         struct async_extent *async_extent;
 662         u64 alloc_hint = 0;
 663         struct btrfs_key ins;
 664         struct extent_map *em;
 665         struct btrfs_root *root = BTRFS_I(inode)->root;
 666         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 667         struct extent_io_tree *io_tree;
 668         int ret = 0;
 669
 670 again:
 671         while (!list_empty(&async_cow->extents)) {
 672                 async_extent = list_entry(async_cow->extents.next,
 673                                           struct async_extent, list);
 674                 list_del(&async_extent->list);
 675
 676                 io_tree = &BTRFS_I(inode)->io_tree;
 677
 678 retry:
 679                 /* did the compression code fall back to uncompressed IO? */
 680                 if (!async_extent->pages) {
 681                         int page_started = 0;
 682                         unsigned long nr_written = 0;
 683
 684                         lock_extent(io_tree, async_extent->start,
 685                                          async_extent->start +
 686                                          async_extent->ram_size - 1);
 687
 688                         /* allocate blocks */
 689                         ret = cow_file_range(inode, async_cow->locked_page,
 690                                              async_extent->start,
 691                                              async_extent->start +
 692                                              async_extent->ram_size - 1,
 693                                              &page_started, &nr_written, 0);
 694
 695                         /* JDM XXX */
 696
 697                         /*
 698                          * if page_started, cow_file_range inserted an
 699                          * inline extent and took care of all the unlocking
 700                          * and IO for us.  Otherwise, we need to submit
 701                          * all those pages down to the drive.
 702                          */
 703                         if (!page_started && !ret)
 704                                 extent_write_locked_range(io_tree,
 705                                                   inode, async_extent->start,
 706                                                   async_extent->start +
 707                                                   async_extent->ram_size - 1,
 708                                                   btrfs_get_extent,
 709                                                   WB_SYNC_ALL);
 710                         else if (ret)
 711                                 unlock_page(async_cow->locked_page);
 712                         kfree(async_extent);
 713                         cond_resched();
 714                         continue;
 715                 }
 716
 717                 lock_extent(io_tree, async_extent->start,
 718                             async_extent->start + async_extent->ram_size - 1);
 719
 720                 ret = btrfs_reserve_extent(root,
 721                                            async_extent->compressed_size,
 722                                            async_extent->compressed_size,
 723                                            0, alloc_hint, &ins, 1, 1);
 724                 if (ret) {
 725                         free_async_extent_pages(async_extent);
 726
 727                         if (ret == -ENOSPC) {
 728                                 unlock_extent(io_tree, async_extent->start,
 729                                               async_extent->start +
 730                                               async_extent->ram_size - 1);
 731
 732                                 /*
 733                                  * we need to redirty the pages if we decide to
 734                                  * fallback to uncompressed IO, otherwise we
 735                                  * will not submit these pages down to lower
 736                                  * layers.
 737                                  */
 738                                 extent_range_redirty_for_io(inode,
 739                                                 async_extent->start,
 740                                                 async_extent->start +
 741                                                 async_extent->ram_size - 1);
 742
 743                                 goto retry;
 744                         }
 745                         goto out_free;
 746                 }
 747
 748                 /*
 749                  * here we're doing allocation and writeback of the
 750                  * compressed pages
 751                  */
 752                 btrfs_drop_extent_cache(inode, async_extent->start,
 753                                         async_extent->start +
 754                                         async_extent->ram_size - 1, 0);
 755
 756                 em = alloc_extent_map();
 757                 if (!em) {
 758                         ret = -ENOMEM;
 759                         goto out_free_reserve;
 760                 }
 761                 em->start = async_extent->start;
 762                 em->len = async_extent->ram_size;
 763                 em->orig_start = em->start;
 764                 em->mod_start = em->start;
 765                 em->mod_len = em->len;
 766
 767                 em->block_start = ins.objectid;
 768                 em->block_len = ins.offset;
 769                 em->orig_block_len = ins.offset;
 770                 em->ram_bytes = async_extent->ram_size;
 771                 em->bdev = root->fs_info->fs_devices->latest_bdev;
 772                 em->compress_type = async_extent->compress_type;
 773                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 774                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 775                 em->generation = -1;
 776
 777                 while (1) {
 778                         write_lock(&em_tree->lock);
 779                         ret = add_extent_mapping(em_tree, em, 1);
 780                         write_unlock(&em_tree->lock);
 781                         if (ret != -EEXIST) {
 782                                 free_extent_map(em);
 783                                 break;
 784                         }
 785                         btrfs_drop_extent_cache(inode, async_extent->start,
 786                                                 async_extent->start +
 787                                                 async_extent->ram_size - 1, 0);
 788                 }
 789
 790                 if (ret)
 791                         goto out_free_reserve;
 792
 793                 ret = btrfs_add_ordered_extent_compress(inode,
 794                                                 async_extent->start,
 795                                                 ins.objectid,
 796                                                 async_extent->ram_size,
 797                                                 ins.offset,
 798                                                 BTRFS_ORDERED_COMPRESSED,
 799                                                 async_extent->compress_type);
 800                 if (ret) {
 801                         btrfs_drop_extent_cache(inode, async_extent->start,
 802                                                 async_extent->start +
 803                                                 async_extent->ram_size - 1, 0);
 804                         goto out_free_reserve;
 805                 }
 806
 807                 /*
 808                  * clear dirty, set writeback and unlock the pages.
 809                  */
 810                 extent_clear_unlock_delalloc(inode, async_extent->start,
 811                                 async_extent->start +
 812                                 async_extent->ram_size - 1,
 813                                 NULL, EXTENT_LOCKED | EXTENT_DELALLOC,
 814                                 PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 815                                 PAGE_SET_WRITEBACK);
 816                 ret = btrfs_submit_compressed_write(inode,
 817                                     async_extent->start,
 818                                     async_extent->ram_size,
 819                                     ins.objectid,
 820                                     ins.offset, async_extent->pages,
 821                                     async_extent->nr_pages);
 822                 if (ret) {
 823                         struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
 824                         struct page *p = async_extent->pages[0];
 825                         const u64 start = async_extent->start;
 826                         const u64 end = start + async_extent->ram_size - 1;
 827
 828                         p->mapping = inode->i_mapping;
 829                         tree->ops->writepage_end_io_hook(p, start, end,
 830                                                          NULL, 0);
 831                         p->mapping = NULL;
 832                         extent_clear_unlock_delalloc(inode, start, end, NULL, 0,
 833                                                      PAGE_END_WRITEBACK |
 834                                                      PAGE_SET_ERROR);
 835                         free_async_extent_pages(async_extent);
 836                 }
 837                 alloc_hint = ins.objectid + ins.offset;
 838                 kfree(async_extent);
 839                 cond_resched();
 840         }
 841         return;
 842 out_free_reserve:
 843         btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
 844 out_free:
 845         extent_clear_unlock_delalloc(inode, async_extent->start,
 846                                      async_extent->start +
 847                                      async_extent->ram_size - 1,
 848                                      NULL, EXTENT_LOCKED | EXTENT_DELALLOC |
 849                                      EXTENT_DEFRAG | EXTENT_DO_ACCOUNTING,
 850                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 851                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK |
 852                                      PAGE_SET_ERROR);
 853         free_async_extent_pages(async_extent);
 854         kfree(async_extent);
 855         goto again;
 856 }
 857
 858 static u64 get_extent_allocation_hint(struct inode *inode, u64 start,
 859                                       u64 num_bytes)
 860 {
 861         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 862         struct extent_map *em;
 863         u64 alloc_hint = 0;
 864
 865         read_lock(&em_tree->lock);
 866         em = search_extent_mapping(em_tree, start, num_bytes);
 867         if (em) {
 868                 /*
 869                  * if block start isn't an actual block number then find the
 870                  * first block in this inode and use that as a hint.  If that
 871                  * block is also bogus then just don't worry about it.
 872                  */
 873                 if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
 874                         free_extent_map(em);
 875                         em = search_extent_mapping(em_tree, 0, 0);
 876                         if (em && em->block_start < EXTENT_MAP_LAST_BYTE)
 877                                 alloc_hint = em->block_start;
 878                         if (em)
 879                                 free_extent_map(em);
 880                 } else {
 881                         alloc_hint = em->block_start;
 882                         free_extent_map(em);
 883                 }
 884         }
 885         read_unlock(&em_tree->lock);
 886
 887         return alloc_hint;
 888 }
 889
 890 /*
 891  * when extent_io.c finds a delayed allocation range in the file,
 892  * the call backs end up in this code.  The basic idea is to
 893  * allocate extents on disk for the range, and create ordered data structs
 894  * in ram to track those extents.
 895  *
 896  * locked_page is the page that writepage had locked already.  We use
 897  * it to make sure we don't do extra locks or unlocks.
 898  *
 899  * *page_started is set to one if we unlock locked_page and do everything
 900  * required to start IO on it.  It may be clean and already done with
 901  * IO when we return.
 902  */
 903 static noinline int cow_file_range(struct inode *inode,
 904                                    struct page *locked_page,
 905                                    u64 start, u64 end, int *page_started,
 906                                    unsigned long *nr_written,
 907                                    int unlock)
 908 {
 909         struct btrfs_root *root = BTRFS_I(inode)->root;
 910         u64 alloc_hint = 0;
 911         u64 num_bytes;
 912         unsigned long ram_size;
 913         u64 disk_num_bytes;
 914         u64 cur_alloc_size;
 915         u64 blocksize = root->sectorsize;
 916         struct btrfs_key ins;
 917         struct extent_map *em;
 918         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 919         int ret = 0;
 920
 921         if (btrfs_is_free_space_inode(inode)) {
 922                 WARN_ON_ONCE(1);
 923                 ret = -EINVAL;
 924                 goto out_unlock;
 925         }
 926
 927         num_bytes = ALIGN(end - start + 1, blocksize);
 928         num_bytes = max(blocksize,  num_bytes);
 929         disk_num_bytes = num_bytes;
 930
 931         /* if this is a small write inside eof, kick off defrag */
 932         if (num_bytes < 64 * 1024 &&
 933             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 934                 btrfs_add_inode_defrag(NULL, inode);
 935
 936         if (start == 0) {
 937                 /* lets try to make an inline extent */
 938                 ret = cow_file_range_inline(root, inode, start, end, 0, 0,
 939                                             NULL);
 940                 if (ret == 0) {
 941                         extent_clear_unlock_delalloc(inode, start, end, NULL,
 942                                      EXTENT_LOCKED | EXTENT_DELALLOC |
 943                                      EXTENT_DEFRAG, PAGE_UNLOCK |
 944                                      PAGE_CLEAR_DIRTY | PAGE_SET_WRITEBACK |
 945                                      PAGE_END_WRITEBACK);
 946
 947                         *nr_written = *nr_written +
 948                              (end - start + PAGE_CACHE_SIZE) / PAGE_CACHE_SIZE;
 949                         *page_started = 1;
 950                         goto out;
 951                 } else if (ret < 0) {
 952                         goto out_unlock;
 953                 }
 954         }
 955
 956         BUG_ON(disk_num_bytes >
 957                btrfs_super_total_bytes(root->fs_info->super_copy));
 958
 959         alloc_hint = get_extent_allocation_hint(inode, start, num_bytes);
 960         btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
 961
 962         while (disk_num_bytes > 0) {
 963                 unsigned long op;
 964
 965                 cur_alloc_size = disk_num_bytes;
 966                 ret = btrfs_reserve_extent(root, cur_alloc_size,
 967                                            root->sectorsize, 0, alloc_hint,
 968                                            &ins, 1, 1);
 969                 if (ret < 0)
 970                         goto out_unlock;
 971
 972                 em = alloc_extent_map();
 973                 if (!em) {
 974                         ret = -ENOMEM;
 975                         goto out_reserve;
 976                 }
 977                 em->start = start;
 978                 em->orig_start = em->start;
 979                 ram_size = ins.offset;
 980                 em->len = ins.offset;
 981                 em->mod_start = em->start;
 982                 em->mod_len = em->len;
 983
 984                 em->block_start = ins.objectid;
 985                 em->block_len = ins.offset;
 986                 em->orig_block_len = ins.offset;
 987                 em->ram_bytes = ram_size;
 988                 em->bdev = root->fs_info->fs_devices->latest_bdev;
 989                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 990                 em->generation = -1;
 991
 992                 while (1) {
 993                         write_lock(&em_tree->lock);
 994                         ret = add_extent_mapping(em_tree, em, 1);
 995                         write_unlock(&em_tree->lock);
 996                         if (ret != -EEXIST) {
 997                                 free_extent_map(em);
 998                                 break;
 999                         }
1000                         btrfs_drop_extent_cache(inode, start,
1001                                                 start + ram_size - 1, 0);
1002                 }
1003                 if (ret)
1004                         goto out_reserve;
1005
1006                 cur_alloc_size = ins.offset;
1007                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
1008                                                ram_size, cur_alloc_size, 0);
1009                 if (ret)
1010                         goto out_drop_extent_cache;
1011
1012                 if (root->root_key.objectid ==
1013                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1014                         ret = btrfs_reloc_clone_csums(inode, start,
1015                                                       cur_alloc_size);
1016                         if (ret)
1017                                 goto out_drop_extent_cache;
1018                 }
1019
1020                 if (disk_num_bytes < cur_alloc_size)
1021                         break;
1022
1023                 /* we're not doing compressed IO, don't unlock the first
1024                  * page (which the caller expects to stay locked), don't
1025                  * clear any dirty bits and don't set any writeback bits
1026                  *
1027                  * Do set the Private2 bit so we know this page was properly
1028                  * setup for writepage
1029                  */
1030                 op = unlock ? PAGE_UNLOCK : 0;
1031                 op |= PAGE_SET_PRIVATE2;
1032
1033                 extent_clear_unlock_delalloc(inode, start,
1034                                              start + ram_size - 1, locked_page,
1035                                              EXTENT_LOCKED | EXTENT_DELALLOC,
1036                                              op);
1037                 disk_num_bytes -= cur_alloc_size;
1038                 num_bytes -= cur_alloc_size;
1039                 alloc_hint = ins.objectid + ins.offset;
1040                 start += cur_alloc_size;
1041         }
1042 out:
1043         return ret;
1044
1045 out_drop_extent_cache:
1046         btrfs_drop_extent_cache(inode, start, start + ram_size - 1, 0);
1047 out_reserve:
1048         btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
1049 out_unlock:
1050         extent_clear_unlock_delalloc(inode, start, end, locked_page,
1051                                      EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
1052                                      EXTENT_DELALLOC | EXTENT_DEFRAG,
1053                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
1054                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK);
1055         goto out;
1056 }
1057
1058 /*
1059  * work queue call back to started compression on a file and pages
1060  */
1061 static noinline void async_cow_start(struct btrfs_work *work)
1062 {
1063         struct async_cow *async_cow;
1064         int num_added = 0;
1065         async_cow = container_of(work, struct async_cow, work);
1066
1067         compress_file_range(async_cow->inode, async_cow->locked_page,
1068                             async_cow->start, async_cow->end, async_cow,
1069                             &num_added);
1070         if (num_added == 0) {
1071                 btrfs_add_delayed_iput(async_cow->inode);
1072                 async_cow->inode = NULL;
1073         }
1074 }
1075
1076 /*
1077  * work queue call back to submit previously compressed pages
1078  */
1079 static noinline void async_cow_submit(struct btrfs_work *work)
1080 {
1081         struct async_cow *async_cow;
1082         struct btrfs_root *root;
1083         unsigned long nr_pages;
1084
1085         async_cow = container_of(work, struct async_cow, work);
1086
1087         root = async_cow->root;
1088         nr_pages = (async_cow->end - async_cow->start + PAGE_CACHE_SIZE) >>
1089                 PAGE_CACHE_SHIFT;
1090
1091         if (atomic_sub_return(nr_pages, &root->fs_info->async_delalloc_pages) <
1092             5 * 1024 * 1024 &&
1093             waitqueue_active(&root->fs_info->async_submit_wait))
1094                 wake_up(&root->fs_info->async_submit_wait);
1095
1096         if (async_cow->inode)
1097                 submit_compressed_extents(async_cow->inode, async_cow);
1098 }
1099
1100 static noinline void async_cow_free(struct btrfs_work *work)
1101 {
1102         struct async_cow *async_cow;
1103         async_cow = container_of(work, struct async_cow, work);
1104         if (async_cow->inode)
1105                 btrfs_add_delayed_iput(async_cow->inode);
1106         kfree(async_cow);
1107 }
1108
1109 static int cow_file_range_async(struct inode *inode, struct page *locked_page,
1110                                 u64 start, u64 end, int *page_started,
1111                                 unsigned long *nr_written)
1112 {
1113         struct async_cow *async_cow;
1114         struct btrfs_root *root = BTRFS_I(inode)->root;
1115         unsigned long nr_pages;
1116         u64 cur_end;
1117         int limit = 10 * 1024 * 1024;
1118
1119         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
1120                          1, 0, NULL, GFP_NOFS);
1121         while (start < end) {
1122                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
1123                 BUG_ON(!async_cow); /* -ENOMEM */
1124                 async_cow->inode = igrab(inode);
1125                 async_cow->root = root;
1126                 async_cow->locked_page = locked_page;
1127                 async_cow->start = start;
1128
1129                 if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS &&
1130                     !btrfs_test_opt(root, FORCE_COMPRESS))
1131                         cur_end = end;
1132                 else
1133                         cur_end = min(end, start + 512 * 1024 - 1);
1134
1135                 async_cow->end = cur_end;
1136                 INIT_LIST_HEAD(&async_cow->extents);
1137
1138                 btrfs_init_work(&async_cow->work,
1139                                 btrfs_delalloc_helper,
1140                                 async_cow_start, async_cow_submit,
1141                                 async_cow_free);
1142
1143                 nr_pages = (cur_end - start + PAGE_CACHE_SIZE) >>
1144                         PAGE_CACHE_SHIFT;
1145                 atomic_add(nr_pages, &root->fs_info->async_delalloc_pages);
1146
1147                 btrfs_queue_work(root->fs_info->delalloc_workers,
1148                                  &async_cow->work);
1149
1150                 if (atomic_read(&root->fs_info->async_delalloc_pages) > limit) {
1151                         wait_event(root->fs_info->async_submit_wait,
1152                            (atomic_read(&root->fs_info->async_delalloc_pages) <
1153                             limit));
1154                 }
1155
1156                 while (atomic_read(&root->fs_info->async_submit_draining) &&
1157                       atomic_read(&root->fs_info->async_delalloc_pages)) {
1158                         wait_event(root->fs_info->async_submit_wait,
1159                           (atomic_read(&root->fs_info->async_delalloc_pages) ==
1160                            0));
1161                 }
1162
1163                 *nr_written += nr_pages;
1164                 start = cur_end + 1;
1165         }
1166         *page_started = 1;
1167         return 0;
1168 }
1169
1170 static noinline int csum_exist_in_range(struct btrfs_root *root,
1171                                         u64 bytenr, u64 num_bytes)
1172 {
1173         int ret;
1174         struct btrfs_ordered_sum *sums;
1175         LIST_HEAD(list);
1176
1177         ret = btrfs_lookup_csums_range(root->fs_info->csum_root, bytenr,
1178                                        bytenr + num_bytes - 1, &list, 0);
1179         if (ret == 0 && list_empty(&list))
1180                 return 0;
1181
1182         while (!list_empty(&list)) {
1183                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
1184                 list_del(&sums->list);
1185                 kfree(sums);
1186         }
1187         return 1;
1188 }
1189
1190 /*
1191  * when nowcow writeback call back.  This checks for snapshots or COW copies
1192  * of the extents that exist in the file, and COWs the file as required.
1193  *
1194  * If no cow copies or snapshots exist, we write directly to the existing
1195  * blocks on disk
1196  */
1197 static noinline int run_delalloc_nocow(struct inode *inode,
1198                                        struct page *locked_page,
1199                               u64 start, u64 end, int *page_started, int force,
1200                               unsigned long *nr_written)
1201 {
1202         struct btrfs_root *root = BTRFS_I(inode)->root;
1203         struct btrfs_trans_handle *trans;
1204         struct extent_buffer *leaf;
1205         struct btrfs_path *path;
1206         struct btrfs_file_extent_item *fi;
1207         struct btrfs_key found_key;
1208         u64 cow_start;
1209         u64 cur_offset;
1210         u64 extent_end;
1211         u64 extent_offset;
1212         u64 disk_bytenr;
1213         u64 num_bytes;
1214         u64 disk_num_bytes;
1215         u64 ram_bytes;
1216         int extent_type;
1217         int ret, err;
1218         int type;
1219         int nocow;
1220         int check_prev = 1;
1221         bool nolock;
1222         u64 ino = btrfs_ino(inode);
1223
1224         path = btrfs_alloc_path();
1225         if (!path) {
1226                 extent_clear_unlock_delalloc(inode, start, end, locked_page,
1227                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1228                                              EXTENT_DO_ACCOUNTING |
1229                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1230                                              PAGE_CLEAR_DIRTY |
1231                                              PAGE_SET_WRITEBACK |
1232                                              PAGE_END_WRITEBACK);
1233                 return -ENOMEM;
1234         }
1235
1236         nolock = btrfs_is_free_space_inode(inode);
1237
1238         if (nolock)
1239                 trans = btrfs_join_transaction_nolock(root);
1240         else
1241                 trans = btrfs_join_transaction(root);
1242
1243         if (IS_ERR(trans)) {
1244                 extent_clear_unlock_delalloc(inode, start, end, locked_page,
1245                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1246                                              EXTENT_DO_ACCOUNTING |
1247                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1248                                              PAGE_CLEAR_DIRTY |
1249                                              PAGE_SET_WRITEBACK |
1250                                              PAGE_END_WRITEBACK);
1251                 btrfs_free_path(path);
1252                 return PTR_ERR(trans);
1253         }
1254
1255         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1256
1257         cow_start = (u64)-1;
1258         cur_offset = start;
1259         while (1) {
1260                 ret = btrfs_lookup_file_extent(trans, root, path, ino,
1261                                                cur_offset, 0);
1262                 if (ret < 0)
1263                         goto error;
1264                 if (ret > 0 && path->slots[0] > 0 && check_prev) {
1265                         leaf = path->nodes[0];
1266                         btrfs_item_key_to_cpu(leaf, &found_key,
1267                                               path->slots[0] - 1);
1268                         if (found_key.objectid == ino &&
1269                             found_key.type == BTRFS_EXTENT_DATA_KEY)
1270                                 path->slots[0]--;
1271                 }
1272                 check_prev = 0;
1273 next_slot:
1274                 leaf = path->nodes[0];
1275                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1276                         ret = btrfs_next_leaf(root, path);
1277                         if (ret < 0)
1278                                 goto error;
1279                         if (ret > 0)
1280                                 break;
1281                         leaf = path->nodes[0];
1282                 }
1283
1284                 nocow = 0;
1285                 disk_bytenr = 0;
1286                 num_bytes = 0;
1287                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1288
1289                 if (found_key.objectid > ino ||
1290                     found_key.type > BTRFS_EXTENT_DATA_KEY ||
1291                     found_key.offset > end)
1292                         break;
1293
1294                 if (found_key.offset > cur_offset) {
1295                         extent_end = found_key.offset;
1296                         extent_type = 0;
1297                         goto out_check;
1298                 }
1299
1300                 fi = btrfs_item_ptr(leaf, path->slots[0],
1301                                     struct btrfs_file_extent_item);
1302                 extent_type = btrfs_file_extent_type(leaf, fi);
1303
1304                 ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
1305                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
1306                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1307                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1308                         extent_offset = btrfs_file_extent_offset(leaf, fi);
1309                         extent_end = found_key.offset +
1310                                 btrfs_file_extent_num_bytes(leaf, fi);
1311                         disk_num_bytes =
1312                                 btrfs_file_extent_disk_num_bytes(leaf, fi);
1313                         if (extent_end <= start) {
1314                                 path->slots[0]++;
1315                                 goto next_slot;
1316                         }
1317                         if (disk_bytenr == 0)
1318                                 goto out_check;
1319                         if (btrfs_file_extent_compression(leaf, fi) ||
1320                             btrfs_file_extent_encryption(leaf, fi) ||
1321                             btrfs_file_extent_other_encoding(leaf, fi))
1322                                 goto out_check;
1323                         if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1324                                 goto out_check;
1325                         if (btrfs_extent_readonly(root, disk_bytenr))
1326                                 goto out_check;
1327                         if (btrfs_cross_ref_exist(trans, root, ino,
1328                                                   found_key.offset -
1329                                                   extent_offset, disk_bytenr))
1330                                 goto out_check;
1331                         disk_bytenr += extent_offset;
1332                         disk_bytenr += cur_offset - found_key.offset;
1333                         num_bytes = min(end + 1, extent_end) - cur_offset;
1334                         /*
1335                          * if there are pending snapshots for this root,
1336                          * we fall into common COW way.
1337                          */
1338                         if (!nolock) {
1339                                 err = btrfs_start_nocow_write(root);
1340                                 if (!err)
1341                                         goto out_check;
1342                         }
1343                         /*
1344                          * force cow if csum exists in the range.
1345                          * this ensure that csum for a given extent are
1346                          * either valid or do not exist.
1347                          */
1348                         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
1349                                 goto out_check;
1350                         nocow = 1;
1351                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1352                         extent_end = found_key.offset +
1353                                 btrfs_file_extent_inline_len(leaf,
1354                                                      path->slots[0], fi);
1355                         extent_end = ALIGN(extent_end, root->sectorsize);
1356                 } else {
1357                         BUG_ON(1);
1358                 }
1359 out_check:
1360                 if (extent_end <= start) {
1361                         path->slots[0]++;
1362                         if (!nolock && nocow)
1363                                 btrfs_end_nocow_write(root);
1364                         goto next_slot;
1365                 }
1366                 if (!nocow) {
1367                         if (cow_start == (u64)-1)
1368                                 cow_start = cur_offset;
1369                         cur_offset = extent_end;
1370                         if (cur_offset > end)
1371                                 break;
1372                         path->slots[0]++;
1373                         goto next_slot;
1374                 }
1375
1376                 btrfs_release_path(path);
1377                 if (cow_start != (u64)-1) {
1378                         ret = cow_file_range(inode, locked_page,
1379                                              cow_start, found_key.offset - 1,
1380                                              page_started, nr_written, 1);
1381                         if (ret) {
1382                                 if (!nolock && nocow)
1383                                         btrfs_end_nocow_write(root);
1384                                 goto error;
1385                         }
1386                         cow_start = (u64)-1;
1387                 }
1388
1389                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1390                         struct extent_map *em;
1391                         struct extent_map_tree *em_tree;
1392                         em_tree = &BTRFS_I(inode)->extent_tree;
1393                         em = alloc_extent_map();
1394                         BUG_ON(!em); /* -ENOMEM */
1395                         em->start = cur_offset;
1396                         em->orig_start = found_key.offset - extent_offset;
1397                         em->len = num_bytes;
1398                         em->block_len = num_bytes;
1399                         em->block_start = disk_bytenr;
1400                         em->orig_block_len = disk_num_bytes;
1401                         em->ram_bytes = ram_bytes;
1402                         em->bdev = root->fs_info->fs_devices->latest_bdev;
1403                         em->mod_start = em->start;
1404                         em->mod_len = em->len;
1405                         set_bit(EXTENT_FLAG_PINNED, &em->flags);
1406                         set_bit(EXTENT_FLAG_FILLING, &em->flags);
1407                         em->generation = -1;
1408                         while (1) {
1409                                 write_lock(&em_tree->lock);
1410                                 ret = add_extent_mapping(em_tree, em, 1);
1411                                 write_unlock(&em_tree->lock);
1412                                 if (ret != -EEXIST) {
1413                                         free_extent_map(em);
1414                                         break;
1415                                 }
1416                                 btrfs_drop_extent_cache(inode, em->start,
1417                                                 em->start + em->len - 1, 0);
1418                         }
1419                         type = BTRFS_ORDERED_PREALLOC;
1420                 } else {
1421                         type = BTRFS_ORDERED_NOCOW;
1422                 }
1423
1424                 ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
1425                                                num_bytes, num_bytes, type);
1426                 BUG_ON(ret); /* -ENOMEM */
1427
1428                 if (root->root_key.objectid ==
1429                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1430                         ret = btrfs_reloc_clone_csums(inode, cur_offset,
1431                                                       num_bytes);
1432                         if (ret) {
1433                                 if (!nolock && nocow)
1434                                         btrfs_end_nocow_write(root);
1435                                 goto error;
1436                         }
1437                 }
1438
1439                 extent_clear_unlock_delalloc(inode, cur_offset,
1440                                              cur_offset + num_bytes - 1,
1441                                              locked_page, EXTENT_LOCKED |
1442                                              EXTENT_DELALLOC, PAGE_UNLOCK |
1443                                              PAGE_SET_PRIVATE2);
1444                 if (!nolock && nocow)
1445                         btrfs_end_nocow_write(root);
1446                 cur_offset = extent_end;
1447                 if (cur_offset > end)
1448                         break;
1449         }
1450         btrfs_release_path(path);
1451
1452         if (cur_offset <= end && cow_start == (u64)-1) {
1453                 cow_start = cur_offset;
1454                 cur_offset = end;
1455         }
1456
1457         if (cow_start != (u64)-1) {
1458                 ret = cow_file_range(inode, locked_page, cow_start, end,
1459                                      page_started, nr_written, 1);
1460                 if (ret)
1461                         goto error;
1462         }
1463
1464 error:
1465         err = btrfs_end_transaction(trans, root);
1466         if (!ret)
1467                 ret = err;
1468
1469         if (ret && cur_offset < end)
1470                 extent_clear_unlock_delalloc(inode, cur_offset, end,
1471                                              locked_page, EXTENT_LOCKED |
1472                                              EXTENT_DELALLOC | EXTENT_DEFRAG |
1473                                              EXTENT_DO_ACCOUNTING, PAGE_UNLOCK |
1474                                              PAGE_CLEAR_DIRTY |
1475                                              PAGE_SET_WRITEBACK |
1476                                              PAGE_END_WRITEBACK);
1477         btrfs_free_path(path);
1478         return ret;
1479 }
1480
1481 static inline int need_force_cow(struct inode *inode, u64 start, u64 end)
1482 {
1483
1484         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
1485             !(BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC))
1486                 return 0;
1487
1488         /*
1489          * @defrag_bytes is a hint value, no spinlock held here,
1490          * if is not zero, it means the file is defragging.
1491          * Force cow if given extent needs to be defragged.
1492          */
1493         if (BTRFS_I(inode)->defrag_bytes &&
1494             test_range_bit(&BTRFS_I(inode)->io_tree, start, end,
1495                            EXTENT_DEFRAG, 0, NULL))
1496                 return 1;
1497
1498         return 0;
1499 }
1500
1501 /*
1502  * extent_io.c call back to do delayed allocation processing
1503  */
1504 static int run_delalloc_range(struct inode *inode, struct page *locked_page,
1505                               u64 start, u64 end, int *page_started,
1506                               unsigned long *nr_written)
1507 {
1508         int ret;
1509         int force_cow = need_force_cow(inode, start, end);
1510
1511         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW && !force_cow) {
1512                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1513                                          page_started, 1, nr_written);
1514         } else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC && !force_cow) {
1515                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1516                                          page_started, 0, nr_written);
1517         } else if (!inode_need_compress(inode)) {
1518                 ret = cow_file_range(inode, locked_page, start, end,
1519                                       page_started, nr_written, 1);
1520         } else {
1521                 set_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1522                         &BTRFS_I(inode)->runtime_flags);
1523                 ret = cow_file_range_async(inode, locked_page, start, end,
1524                                            page_started, nr_written);
1525         }
1526         return ret;
1527 }
1528
1529 static void btrfs_split_extent_hook(struct inode *inode,
1530                                     struct extent_state *orig, u64 split)
1531 {
1532         /* not delalloc, ignore it */
1533         if (!(orig->state & EXTENT_DELALLOC))
1534                 return;
1535
1536         spin_lock(&BTRFS_I(inode)->lock);
1537         BTRFS_I(inode)->outstanding_extents++;
1538         spin_unlock(&BTRFS_I(inode)->lock);
1539 }
1540
1541 /*
1542  * extent_io.c merge_extent_hook, used to track merged delayed allocation
1543  * extents so we can keep track of new extents that are just merged onto old
1544  * extents, such as when we are doing sequential writes, so we can properly
1545  * account for the metadata space we'll need.
1546  */
1547 static void btrfs_merge_extent_hook(struct inode *inode,
1548                                     struct extent_state *new,
1549                                     struct extent_state *other)
1550 {
1551         /* not delalloc, ignore it */
1552         if (!(other->state & EXTENT_DELALLOC))
1553                 return;
1554
1555         spin_lock(&BTRFS_I(inode)->lock);
1556         BTRFS_I(inode)->outstanding_extents--;
1557         spin_unlock(&BTRFS_I(inode)->lock);
1558 }
1559
1560 static void btrfs_add_delalloc_inodes(struct btrfs_root *root,
1561                                       struct inode *inode)
1562 {
1563         spin_lock(&root->delalloc_lock);
1564         if (list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1565                 list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1566                               &root->delalloc_inodes);
1567                 set_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1568                         &BTRFS_I(inode)->runtime_flags);
1569                 root->nr_delalloc_inodes++;
1570                 if (root->nr_delalloc_inodes == 1) {
1571                         spin_lock(&root->fs_info->delalloc_root_lock);
1572                         BUG_ON(!list_empty(&root->delalloc_root));
1573                         list_add_tail(&root->delalloc_root,
1574                                       &root->fs_info->delalloc_roots);
1575                         spin_unlock(&root->fs_info->delalloc_root_lock);
1576                 }
1577         }
1578         spin_unlock(&root->delalloc_lock);
1579 }
1580
1581 static void btrfs_del_delalloc_inode(struct btrfs_root *root,
1582                                      struct inode *inode)
1583 {
1584         spin_lock(&root->delalloc_lock);
1585         if (!list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1586                 list_del_init(&BTRFS_I(inode)->delalloc_inodes);
1587                 clear_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1588                           &BTRFS_I(inode)->runtime_flags);
1589                 root->nr_delalloc_inodes--;
1590                 if (!root->nr_delalloc_inodes) {
1591                         spin_lock(&root->fs_info->delalloc_root_lock);
1592                         BUG_ON(list_empty(&root->delalloc_root));
1593                         list_del_init(&root->delalloc_root);
1594                         spin_unlock(&root->fs_info->delalloc_root_lock);
1595                 }
1596         }
1597         spin_unlock(&root->delalloc_lock);
1598 }
1599
1600 /*
1601  * extent_io.c set_bit_hook, used to track delayed allocation
1602  * bytes in this file, and to maintain the list of inodes that
1603  * have pending delalloc work to be done.
1604  */
1605 static void btrfs_set_bit_hook(struct inode *inode,
1606                                struct extent_state *state, unsigned long *bits)
1607 {
1608
1609         if ((*bits & EXTENT_DEFRAG) && !(*bits & EXTENT_DELALLOC))
1610                 WARN_ON(1);
1611         /*
1612          * set_bit and clear bit hooks normally require _irqsave/restore
1613          * but in this case, we are only testing for the DELALLOC
1614          * bit, which is only set or cleared with irqs on
1615          */
1616         if (!(state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1617                 struct btrfs_root *root = BTRFS_I(inode)->root;
1618                 u64 len = state->end + 1 - state->start;
1619                 bool do_list = !btrfs_is_free_space_inode(inode);
1620
1621                 if (*bits & EXTENT_FIRST_DELALLOC) {
1622                         *bits &= ~EXTENT_FIRST_DELALLOC;
1623                 } else {
1624                         spin_lock(&BTRFS_I(inode)->lock);
1625                         BTRFS_I(inode)->outstanding_extents++;
1626                         spin_unlock(&BTRFS_I(inode)->lock);
1627                 }
1628
1629                 __percpu_counter_add(&root->fs_info->delalloc_bytes, len,
1630                                      root->fs_info->delalloc_batch);
1631                 spin_lock(&BTRFS_I(inode)->lock);
1632                 BTRFS_I(inode)->delalloc_bytes += len;
1633                 if (*bits & EXTENT_DEFRAG)
1634                         BTRFS_I(inode)->defrag_bytes += len;
1635                 if (do_list && !test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1636                                          &BTRFS_I(inode)->runtime_flags))
1637                         btrfs_add_delalloc_inodes(root, inode);
1638                 spin_unlock(&BTRFS_I(inode)->lock);
1639         }
1640 }
1641
1642 /*
1643  * extent_io.c clear_bit_hook, see set_bit_hook for why
1644  */
1645 static void btrfs_clear_bit_hook(struct inode *inode,
1646                                  struct extent_state *state,
1647                                  unsigned long *bits)
1648 {
1649         u64 len = state->end + 1 - state->start;
1650
1651         spin_lock(&BTRFS_I(inode)->lock);
1652         if ((state->state & EXTENT_DEFRAG) && (*bits & EXTENT_DEFRAG))
1653                 BTRFS_I(inode)->defrag_bytes -= len;
1654         spin_unlock(&BTRFS_I(inode)->lock);
1655
1656         /*
1657          * set_bit and clear bit hooks normally require _irqsave/restore
1658          * but in this case, we are only testing for the DELALLOC
1659          * bit, which is only set or cleared with irqs on
1660          */
1661         if ((state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1662                 struct btrfs_root *root = BTRFS_I(inode)->root;
1663                 bool do_list = !btrfs_is_free_space_inode(inode);
1664
1665                 if (*bits & EXTENT_FIRST_DELALLOC) {
1666                         *bits &= ~EXTENT_FIRST_DELALLOC;
1667                 } else if (!(*bits & EXTENT_DO_ACCOUNTING)) {
1668                         spin_lock(&BTRFS_I(inode)->lock);
1669                         BTRFS_I(inode)->outstanding_extents--;
1670                         spin_unlock(&BTRFS_I(inode)->lock);
1671                 }
1672
1673                 /*
1674                  * We don't reserve metadata space for space cache inodes so we
1675                  * don't need to call dellalloc_release_metadata if there is an
1676                  * error.
1677                  */
1678                 if (*bits & EXTENT_DO_ACCOUNTING &&
1679                     root != root->fs_info->tree_root)
1680                         btrfs_delalloc_release_metadata(inode, len);
1681
1682                 if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
1683                     && do_list && !(state->state & EXTENT_NORESERVE))
1684                         btrfs_free_reserved_data_space(inode, len);
1685
1686                 __percpu_counter_add(&root->fs_info->delalloc_bytes, -len,
1687                                      root->fs_info->delalloc_batch);
1688                 spin_lock(&BTRFS_I(inode)->lock);
1689                 BTRFS_I(inode)->delalloc_bytes -= len;
1690                 if (do_list && BTRFS_I(inode)->delalloc_bytes == 0 &&
1691                     test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1692                              &BTRFS_I(inode)->runtime_flags))
1693                         btrfs_del_delalloc_inode(root, inode);
1694                 spin_unlock(&BTRFS_I(inode)->lock);
1695         }
1696 }
1697
1698 /*
1699  * extent_io.c merge_bio_hook, this must check the chunk tree to make sure
1700  * we don't create bios that span stripes or chunks
1701  */
1702 int btrfs_merge_bio_hook(int rw, struct page *page, unsigned long offset,
1703                          size_t size, struct bio *bio,
1704                          unsigned long bio_flags)
1705 {
1706         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
1707         u64 logical = (u64)bio->bi_iter.bi_sector << 9;
1708         u64 length = 0;
1709         u64 map_length;
1710         int ret;
1711
1712         if (bio_flags & EXTENT_BIO_COMPRESSED)
1713                 return 0;
1714
1715         length = bio->bi_iter.bi_size;
1716         map_length = length;
1717         ret = btrfs_map_block(root->fs_info, rw, logical,
1718                               &map_length, NULL, 0);
1719         /* Will always return 0 with map_multi == NULL */
1720         BUG_ON(ret < 0);
1721         if (map_length < length + size)
1722                 return 1;
1723         return 0;
1724 }
1725
1726 /*
1727  * in order to insert checksums into the metadata in large chunks,
1728  * we wait until bio submission time.   All the pages in the bio are
1729  * checksummed and sums are attached onto the ordered extent record.
1730  *
1731  * At IO completion time the cums attached on the ordered extent record
1732  * are inserted into the btree
1733  */
1734 static int __btrfs_submit_bio_start(struct inode *inode, int rw,
1735                                     struct bio *bio, int mirror_num,
1736                                     unsigned long bio_flags,
1737                                     u64 bio_offset)
1738 {
1739         struct btrfs_root *root = BTRFS_I(inode)->root;
1740         int ret = 0;
1741
1742         ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1743         BUG_ON(ret); /* -ENOMEM */
1744         return 0;
1745 }
1746
1747 /*
1748  * in order to insert checksums into the metadata in large chunks,
1749  * we wait until bio submission time.   All the pages in the bio are
1750  * checksummed and sums are attached onto the ordered extent record.
1751  *
1752  * At IO completion time the cums attached on the ordered extent record
1753  * are inserted into the btree
1754  */
1755 static int __btrfs_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
1756                           int mirror_num, unsigned long bio_flags,
1757                           u64 bio_offset)
1758 {
1759         struct btrfs_root *root = BTRFS_I(inode)->root;
1760         int ret;
1761
1762         ret = btrfs_map_bio(root, rw, bio, mirror_num, 1);
1763         if (ret)
1764                 bio_endio(bio, ret);
1765         return ret;
1766 }
1767
1768 /*
1769  * extent_io.c submission hook. This does the right thing for csum calculation
1770  * on write, or reading the csums from the tree before a read
1771  */
1772 static int btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
1773                           int mirror_num, unsigned long bio_flags,
1774                           u64 bio_offset)
1775 {
1776         struct btrfs_root *root = BTRFS_I(inode)->root;
1777         int ret = 0;
1778         int skip_sum;
1779         int metadata = 0;
1780         int async = !atomic_read(&BTRFS_I(inode)->sync_writers);
1781
1782         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
1783
1784         if (btrfs_is_free_space_inode(inode))
1785                 metadata = 2;
1786
1787         if (!(rw & REQ_WRITE)) {
1788                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, metadata);
1789                 if (ret)
1790                         goto out;
1791
1792                 if (bio_flags & EXTENT_BIO_COMPRESSED) {
1793                         ret = btrfs_submit_compressed_read(inode, bio,
1794                                                            mirror_num,
1795                                                            bio_flags);
1796                         goto out;
1797                 } else if (!skip_sum) {
1798                         ret = btrfs_lookup_bio_sums(root, inode, bio, NULL);
1799                         if (ret)
1800                                 goto out;
1801                 }
1802                 goto mapit;
1803         } else if (async && !skip_sum) {
1804                 /* csum items have already been cloned */
1805                 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
1806                         goto mapit;
1807                 /* we're doing a write, do the async checksumming */
1808                 ret = btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
1809                                    inode, rw, bio, mirror_num,
1810                                    bio_flags, bio_offset,
1811                                    __btrfs_submit_bio_start,
1812                                    __btrfs_submit_bio_done);
1813                 goto out;
1814         } else if (!skip_sum) {
1815                 ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1816                 if (ret)
1817                         goto out;
1818         }
1819
1820 mapit:
1821         ret = btrfs_map_bio(root, rw, bio, mirror_num, 0);
1822
1823 out:
1824         if (ret < 0)
1825                 bio_endio(bio, ret);
1826         return ret;
1827 }
1828
1829 /*
1830  * given a list of ordered sums record them in the inode.  This happens
1831  * at IO completion time based on sums calculated at bio submission time.
1832  */
1833 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
1834                              struct inode *inode, u64 file_offset,
1835                              struct list_head *list)
1836 {
1837         struct btrfs_ordered_sum *sum;
1838
1839         list_for_each_entry(sum, list, list) {
1840                 trans->adding_csums = 1;
1841                 btrfs_csum_file_blocks(trans,
1842                        BTRFS_I(inode)->root->fs_info->csum_root, sum);
1843                 trans->adding_csums = 0;
1844         }
1845         return 0;
1846 }
1847
1848 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
1849                               struct extent_state **cached_state)
1850 {
1851         WARN_ON((end & (PAGE_CACHE_SIZE - 1)) == 0);
1852         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
1853                                    cached_state, GFP_NOFS);
1854 }
1855
1856 /* see btrfs_writepage_start_hook for details on why this is required */
1857 struct btrfs_writepage_fixup {
1858         struct page *page;
1859         struct btrfs_work work;
1860 };
1861
1862 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
1863 {
1864         struct btrfs_writepage_fixup *fixup;
1865         struct btrfs_ordered_extent *ordered;
1866         struct extent_state *cached_state = NULL;
1867         struct page *page;
1868         struct inode *inode;
1869         u64 page_start;
1870         u64 page_end;
1871         int ret;
1872
1873         fixup = container_of(work, struct btrfs_writepage_fixup, work);
1874         page = fixup->page;
1875 again:
1876         lock_page(page);
1877         if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
1878                 ClearPageChecked(page);
1879                 goto out_page;
1880         }
1881
1882         inode = page->mapping->host;
1883         page_start = page_offset(page);
1884         page_end = page_offset(page) + PAGE_CACHE_SIZE - 1;
1885
1886         lock_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end, 0,
1887                          &cached_state);
1888
1889         /* already ordered? We're done */
1890         if (PagePrivate2(page))
1891                 goto out;
1892
1893         ordered = btrfs_lookup_ordered_extent(inode, page_start);
1894         if (ordered) {
1895                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start,
1896                                      page_end, &cached_state, GFP_NOFS);
1897                 unlock_page(page);
1898                 btrfs_start_ordered_extent(inode, ordered, 1);
1899                 btrfs_put_ordered_extent(ordered);
1900                 goto again;
1901         }
1902
1903         ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
1904         if (ret) {
1905                 mapping_set_error(page->mapping, ret);
1906                 end_extent_writepage(page, ret, page_start, page_end);
1907                 ClearPageChecked(page);
1908                 goto out;
1909          }
1910
1911         btrfs_set_extent_delalloc(inode, page_start, page_end, &cached_state);
1912         ClearPageChecked(page);
1913         set_page_dirty(page);
1914 out:
1915         unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start, page_end,
1916                              &cached_state, GFP_NOFS);
1917 out_page:
1918         unlock_page(page);
1919         page_cache_release(page);
1920         kfree(fixup);
1921 }
1922
1923 /*
1924  * There are a few paths in the higher layers of the kernel that directly
1925  * set the page dirty bit without asking the filesystem if it is a
1926  * good idea.  This causes problems because we want to make sure COW
1927  * properly happens and the data=ordered rules are followed.
1928  *
1929  * In our case any range that doesn't have the ORDERED bit set
1930  * hasn't been properly setup for IO.  We kick off an async process
1931  * to fix it up.  The async helper will wait for ordered extents, set
1932  * the delalloc bit and make it safe to write the page.
1933  */
1934 static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
1935 {
1936         struct inode *inode = page->mapping->host;
1937         struct btrfs_writepage_fixup *fixup;
1938         struct btrfs_root *root = BTRFS_I(inode)->root;
1939
1940         /* this page is properly in the ordered list */
1941         if (TestClearPagePrivate2(page))
1942                 return 0;
1943
1944         if (PageChecked(page))
1945                 return -EAGAIN;
1946
1947         fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
1948         if (!fixup)
1949                 return -EAGAIN;
1950
1951         SetPageChecked(page);
1952         page_cache_get(page);
1953         btrfs_init_work(&fixup->work, btrfs_fixup_helper,
1954                         btrfs_writepage_fixup_worker, NULL, NULL);
1955         fixup->page = page;
1956         btrfs_queue_work(root->fs_info->fixup_workers, &fixup->work);
1957         return -EBUSY;
1958 }
1959
1960 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
1961                                        struct inode *inode, u64 file_pos,
1962                                        u64 disk_bytenr, u64 disk_num_bytes,
1963                                        u64 num_bytes, u64 ram_bytes,
1964                                        u8 compression, u8 encryption,
1965                                        u16 other_encoding, int extent_type)
1966 {
1967         struct btrfs_root *root = BTRFS_I(inode)->root;
1968         struct btrfs_file_extent_item *fi;
1969         struct btrfs_path *path;
1970         struct extent_buffer *leaf;
1971         struct btrfs_key ins;
1972         int extent_inserted = 0;
1973         int ret;
1974
1975         path = btrfs_alloc_path();
1976         if (!path)
1977                 return -ENOMEM;
1978
1979         /*
1980          * we may be replacing one extent in the tree with another.
1981          * The new extent is pinned in the extent map, and we don't want
1982          * to drop it from the cache until it is completely in the btree.
1983          *
1984          * So, tell btrfs_drop_extents to leave this extent in the cache.
1985          * the caller is expected to unpin it and allow it to be merged
1986          * with the others.
1987          */
1988         ret = __btrfs_drop_extents(trans, root, inode, path, file_pos,
1989                                    file_pos + num_bytes, NULL, 0,
1990                                    1, sizeof(*fi), &extent_inserted);
1991         if (ret)
1992                 goto out;
1993
1994         if (!extent_inserted) {
1995                 ins.objectid = btrfs_ino(inode);
1996                 ins.offset = file_pos;
1997                 ins.type = BTRFS_EXTENT_DATA_KEY;
1998
1999                 path->leave_spinning = 1;
2000                 ret = btrfs_insert_empty_item(trans, root, path, &ins,
2001                                               sizeof(*fi));
2002                 if (ret)
2003                         goto out;
2004         }
2005         leaf = path->nodes[0];
2006         fi = btrfs_item_ptr(leaf, path->slots[0],
2007                             struct btrfs_file_extent_item);
2008         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
2009         btrfs_set_file_extent_type(leaf, fi, extent_type);
2010         btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
2011         btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
2012         btrfs_set_file_extent_offset(leaf, fi, 0);
2013         btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
2014         btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
2015         btrfs_set_file_extent_compression(leaf, fi, compression);
2016         btrfs_set_file_extent_encryption(leaf, fi, encryption);
2017         btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
2018
2019         btrfs_mark_buffer_dirty(leaf);
2020         btrfs_release_path(path);
2021
2022         inode_add_bytes(inode, num_bytes);
2023
2024         ins.objectid = disk_bytenr;
2025         ins.offset = disk_num_bytes;
2026         ins.type = BTRFS_EXTENT_ITEM_KEY;
2027         ret = btrfs_alloc_reserved_file_extent(trans, root,
2028                                         root->root_key.objectid,
2029                                         btrfs_ino(inode), file_pos, &ins);
2030 out:
2031         btrfs_free_path(path);
2032
2033         return ret;
2034 }
2035
2036 /* snapshot-aware defrag */
2037 struct sa_defrag_extent_backref {
2038         struct rb_node node;
2039         struct old_sa_defrag_extent *old;
2040         u64 root_id;
2041         u64 inum;
2042         u64 file_pos;
2043         u64 extent_offset;
2044         u64 num_bytes;
2045         u64 generation;
2046 };
2047
2048 struct old_sa_defrag_extent {
2049         struct list_head list;
2050         struct new_sa_defrag_extent *new;
2051
2052         u64 extent_offset;
2053         u64 bytenr;
2054         u64 offset;
2055         u64 len;
2056         int count;
2057 };
2058
2059 struct new_sa_defrag_extent {
2060         struct rb_root root;
2061         struct list_head head;
2062         struct btrfs_path *path;
2063         struct inode *inode;
2064         u64 file_pos;
2065         u64 len;
2066         u64 bytenr;
2067         u64 disk_len;
2068         u8 compress_type;
2069 };
2070
2071 static int backref_comp(struct sa_defrag_extent_backref *b1,
2072                         struct sa_defrag_extent_backref *b2)
2073 {
2074         if (b1->root_id < b2->root_id)
2075                 return -1;
2076         else if (b1->root_id > b2->root_id)
2077                 return 1;
2078
2079         if (b1->inum < b2->inum)
2080                 return -1;
2081         else if (b1->inum > b2->inum)
2082                 return 1;
2083
2084         if (b1->file_pos < b2->file_pos)
2085                 return -1;
2086         else if (b1->file_pos > b2->file_pos)
2087                 return 1;
2088
2089         /*
2090          * [------------------------------] ===> (a range of space)
2091          *     |<--->|   |<---->| =============> (fs/file tree A)
2092          * |<---------------------------->| ===> (fs/file tree B)
2093          *
2094          * A range of space can refer to two file extents in one tree while
2095          * refer to only one file extent in another tree.
2096          *
2097          * So we may process a disk offset more than one time(two extents in A)
2098          * and locate at the same extent(one extent in B), then insert two same
2099          * backrefs(both refer to the extent in B).
2100          */
2101         return 0;
2102 }
2103
2104 static void backref_insert(struct rb_root *root,
2105                            struct sa_defrag_extent_backref *backref)
2106 {
2107         struct rb_node **p = &root->rb_node;
2108         struct rb_node *parent = NULL;
2109         struct sa_defrag_extent_backref *entry;
2110         int ret;
2111
2112         while (*p) {
2113                 parent = *p;
2114                 entry = rb_entry(parent, struct sa_defrag_extent_backref, node);
2115
2116                 ret = backref_comp(backref, entry);
2117                 if (ret < 0)
2118                         p = &(*p)->rb_left;
2119                 else
2120                         p = &(*p)->rb_right;
2121         }
2122
2123         rb_link_node(&backref->node, parent, p);
2124         rb_insert_color(&backref->node, root);
2125 }
2126
2127 /*
2128  * Note the backref might has changed, and in this case we just return 0.
2129  */
2130 static noinline int record_one_backref(u64 inum, u64 offset, u64 root_id,
2131                                        void *ctx)
2132 {
2133         struct btrfs_file_extent_item *extent;
2134         struct btrfs_fs_info *fs_info;
2135         struct old_sa_defrag_extent *old = ctx;
2136         struct new_sa_defrag_extent *new = old->new;
2137         struct btrfs_path *path = new->path;
2138         struct btrfs_key key;
2139         struct btrfs_root *root;
2140         struct sa_defrag_extent_backref *backref;
2141         struct extent_buffer *leaf;
2142         struct inode *inode = new->inode;
2143         int slot;
2144         int ret;
2145         u64 extent_offset;
2146         u64 num_bytes;
2147
2148         if (BTRFS_I(inode)->root->root_key.objectid == root_id &&
2149             inum == btrfs_ino(inode))
2150                 return 0;
2151
2152         key.objectid = root_id;
2153         key.type = BTRFS_ROOT_ITEM_KEY;
2154         key.offset = (u64)-1;
2155
2156         fs_info = BTRFS_I(inode)->root->fs_info;
2157         root = btrfs_read_fs_root_no_name(fs_info, &key);
2158         if (IS_ERR(root)) {
2159                 if (PTR_ERR(root) == -ENOENT)
2160                         return 0;
2161                 WARN_ON(1);
2162                 pr_debug("inum=%llu, offset=%llu, root_id=%llu\n",
2163                          inum, offset, root_id);
2164                 return PTR_ERR(root);
2165         }
2166
2167         key.objectid = inum;
2168         key.type = BTRFS_EXTENT_DATA_KEY;
2169         if (offset > (u64)-1 << 32)
2170                 key.offset = 0;
2171         else
2172                 key.offset = offset;
2173
2174         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2175         if (WARN_ON(ret < 0))
2176                 return ret;
2177         ret = 0;
2178
2179         while (1) {
2180                 cond_resched();
2181
2182                 leaf = path->nodes[0];
2183                 slot = path->slots[0];
2184
2185                 if (slot >= btrfs_header_nritems(leaf)) {
2186                         ret = btrfs_next_leaf(root, path);
2187                         if (ret < 0) {
2188                                 goto out;
2189                         } else if (ret > 0) {
2190                                 ret = 0;
2191                                 goto out;
2192                         }
2193                         continue;
2194                 }
2195
2196                 path->slots[0]++;
2197
2198                 btrfs_item_key_to_cpu(leaf, &key, slot);
2199
2200                 if (key.objectid > inum)
2201                         goto out;
2202
2203                 if (key.objectid < inum || key.type != BTRFS_EXTENT_DATA_KEY)
2204                         continue;
2205
2206                 extent = btrfs_item_ptr(leaf, slot,
2207                                         struct btrfs_file_extent_item);
2208
2209                 if (btrfs_file_extent_disk_bytenr(leaf, extent) != old->bytenr)
2210                         continue;
2211
2212                 /*
2213                  * 'offset' refers to the exact key.offset,
2214                  * NOT the 'offset' field in btrfs_extent_data_ref, ie.
2215                  * (key.offset - extent_offset).
2216                  */
2217                 if (key.offset != offset)
2218                         continue;
2219
2220                 extent_offset = btrfs_file_extent_offset(leaf, extent);
2221                 num_bytes = btrfs_file_extent_num_bytes(leaf, extent);
2222
2223                 if (extent_offset >= old->extent_offset + old->offset +
2224                     old->len || extent_offset + num_bytes <=
2225                     old->extent_offset + old->offset)
2226                         continue;
2227                 break;
2228         }
2229
2230         backref = kmalloc(sizeof(*backref), GFP_NOFS);
2231         if (!backref) {
2232                 ret = -ENOENT;
2233                 goto out;
2234         }
2235
2236         backref->root_id = root_id;
2237         backref->inum = inum;
2238         backref->file_pos = offset;
2239         backref->num_bytes = num_bytes;
2240         backref->extent_offset = extent_offset;
2241         backref->generation = btrfs_file_extent_generation(leaf, extent);
2242         backref->old = old;
2243         backref_insert(&new->root, backref);
2244         old->count++;
2245 out:
2246         btrfs_release_path(path);
2247         WARN_ON(ret);
2248         return ret;
2249 }
2250
2251 static noinline bool record_extent_backrefs(struct btrfs_path *path,
2252                                    struct new_sa_defrag_extent *new)
2253 {
2254         struct btrfs_fs_info *fs_info = BTRFS_I(new->inode)->root->fs_info;
2255         struct old_sa_defrag_extent *old, *tmp;
2256         int ret;
2257
2258         new->path = path;
2259
2260         list_for_each_entry_safe(old, tmp, &new->head, list) {
2261                 ret = iterate_inodes_from_logical(old->bytenr +
2262                                                   old->extent_offset, fs_info,
2263                                                   path, record_one_backref,
2264                                                   old);
2265                 if (ret < 0 && ret != -ENOENT)
2266                         return false;
2267
2268                 /* no backref to be processed for this extent */
2269                 if (!old->count) {
2270                         list_del(&old->list);
2271                         kfree(old);
2272                 }
2273         }
2274
2275         if (list_empty(&new->head))
2276                 return false;
2277
2278         return true;
2279 }
2280
2281 static int relink_is_mergable(struct extent_buffer *leaf,
2282                               struct btrfs_file_extent_item *fi,
2283                               struct new_sa_defrag_extent *new)
2284 {
2285         if (btrfs_file_extent_disk_bytenr(leaf, fi) != new->bytenr)
2286                 return 0;
2287
2288         if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
2289                 return 0;
2290
2291         if (btrfs_file_extent_compression(leaf, fi) != new->compress_type)
2292                 return 0;
2293
2294         if (btrfs_file_extent_encryption(leaf, fi) ||
2295             btrfs_file_extent_other_encoding(leaf, fi))
2296                 return 0;
2297
2298         return 1;
2299 }
2300
2301 /*
2302  * Note the backref might has changed, and in this case we just return 0.
2303  */
2304 static noinline int relink_extent_backref(struct btrfs_path *path,
2305                                  struct sa_defrag_extent_backref *prev,
2306                                  struct sa_defrag_extent_backref *backref)
2307 {
2308         struct btrfs_file_extent_item *extent;
2309         struct btrfs_file_extent_item *item;
2310         struct btrfs_ordered_extent *ordered;
2311         struct btrfs_trans_handle *trans;
2312         struct btrfs_fs_info *fs_info;
2313         struct btrfs_root *root;
2314         struct btrfs_key key;
2315         struct extent_buffer *leaf;
2316         struct old_sa_defrag_extent *old = backref->old;
2317         struct new_sa_defrag_extent *new = old->new;
2318         struct inode *src_inode = new->inode;
2319         struct inode *inode;
2320         struct extent_state *cached = NULL;
2321         int ret = 0;
2322         u64 start;
2323         u64 len;
2324         u64 lock_start;
2325         u64 lock_end;
2326         bool merge = false;
2327         int index;
2328
2329         if (prev && prev->root_id == backref->root_id &&
2330             prev->inum == backref->inum &&
2331             prev->file_pos + prev->num_bytes == backref->file_pos)
2332                 merge = true;
2333
2334         /* step 1: get root */
2335         key.objectid = backref->root_id;
2336         key.type = BTRFS_ROOT_ITEM_KEY;
2337         key.offset = (u64)-1;
2338
2339         fs_info = BTRFS_I(src_inode)->root->fs_info;
2340         index = srcu_read_lock(&fs_info->subvol_srcu);
2341
2342         root = btrfs_read_fs_root_no_name(fs_info, &key);
2343         if (IS_ERR(root)) {
2344                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2345                 if (PTR_ERR(root) == -ENOENT)
2346                         return 0;
2347                 return PTR_ERR(root);
2348         }
2349
2350         if (btrfs_root_readonly(root)) {
2351                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2352                 return 0;
2353         }
2354
2355         /* step 2: get inode */
2356         key.objectid = backref->inum;
2357         key.type = BTRFS_INODE_ITEM_KEY;
2358         key.offset = 0;
2359
2360         inode = btrfs_iget(fs_info->sb, &key, root, NULL);
2361         if (IS_ERR(inode)) {
2362                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2363                 return 0;
2364         }
2365
2366         srcu_read_unlock(&fs_info->subvol_srcu, index);
2367
2368         /* step 3: relink backref */
2369         lock_start = backref->file_pos;
2370         lock_end = backref->file_pos + backref->num_bytes - 1;
2371         lock_extent_bits(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2372                          0, &cached);
2373
2374         ordered = btrfs_lookup_first_ordered_extent(inode, lock_end);
2375         if (ordered) {
2376                 btrfs_put_ordered_extent(ordered);
2377                 goto out_unlock;
2378         }
2379
2380         trans = btrfs_join_transaction(root);
2381         if (IS_ERR(trans)) {
2382                 ret = PTR_ERR(trans);
2383                 goto out_unlock;
2384         }
2385
2386         key.objectid = backref->inum;
2387         key.type = BTRFS_EXTENT_DATA_KEY;
2388         key.offset = backref->file_pos;
2389
2390         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2391         if (ret < 0) {
2392                 goto out_free_path;
2393         } else if (ret > 0) {
2394                 ret = 0;
2395                 goto out_free_path;
2396         }
2397
2398         extent = btrfs_item_ptr(path->nodes[0], path->slots[0],
2399                                 struct btrfs_file_extent_item);
2400
2401         if (btrfs_file_extent_generation(path->nodes[0], extent) !=
2402             backref->generation)
2403                 goto out_free_path;
2404
2405         btrfs_release_path(path);
2406
2407         start = backref->file_pos;
2408         if (backref->extent_offset < old->extent_offset + old->offset)
2409                 start += old->extent_offset + old->offset -
2410                          backref->extent_offset;
2411
2412         len = min(backref->extent_offset + backref->num_bytes,
2413                   old->extent_offset + old->offset + old->len);
2414         len -= max(backref->extent_offset, old->extent_offset + old->offset);
2415
2416         ret = btrfs_drop_extents(trans, root, inode, start,
2417                                  start + len, 1);
2418         if (ret)
2419                 goto out_free_path;
2420 again:
2421         key.objectid = btrfs_ino(inode);
2422         key.type = BTRFS_EXTENT_DATA_KEY;
2423         key.offset = start;
2424
2425         path->leave_spinning = 1;
2426         if (merge) {
2427                 struct btrfs_file_extent_item *fi;
2428                 u64 extent_len;
2429                 struct btrfs_key found_key;
2430
2431                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2432                 if (ret < 0)
2433                         goto out_free_path;
2434
2435                 path->slots[0]--;
2436                 leaf = path->nodes[0];
2437                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2438
2439                 fi = btrfs_item_ptr(leaf, path->slots[0],
2440                                     struct btrfs_file_extent_item);
2441                 extent_len = btrfs_file_extent_num_bytes(leaf, fi);
2442
2443                 if (extent_len + found_key.offset == start &&
2444                     relink_is_mergable(leaf, fi, new)) {
2445                         btrfs_set_file_extent_num_bytes(leaf, fi,
2446                                                         extent_len + len);
2447                         btrfs_mark_buffer_dirty(leaf);
2448                         inode_add_bytes(inode, len);
2449
2450                         ret = 1;
2451                         goto out_free_path;
2452                 } else {
2453                         merge = false;
2454                         btrfs_release_path(path);
2455                         goto again;
2456                 }
2457         }
2458
2459         ret = btrfs_insert_empty_item(trans, root, path, &key,
2460                                         sizeof(*extent));
2461         if (ret) {
2462                 btrfs_abort_transaction(trans, root, ret);
2463                 goto out_free_path;
2464         }
2465
2466         leaf = path->nodes[0];
2467         item = btrfs_item_ptr(leaf, path->slots[0],
2468                                 struct btrfs_file_extent_item);
2469         btrfs_set_file_extent_disk_bytenr(leaf, item, new->bytenr);
2470         btrfs_set_file_extent_disk_num_bytes(leaf, item, new->disk_len);
2471         btrfs_set_file_extent_offset(leaf, item, start - new->file_pos);
2472         btrfs_set_file_extent_num_bytes(leaf, item, len);
2473         btrfs_set_file_extent_ram_bytes(leaf, item, new->len);
2474         btrfs_set_file_extent_generation(leaf, item, trans->transid);
2475         btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
2476         btrfs_set_file_extent_compression(leaf, item, new->compress_type);
2477         btrfs_set_file_extent_encryption(leaf, item, 0);
2478         btrfs_set_file_extent_other_encoding(leaf, item, 0);
2479
2480         btrfs_mark_buffer_dirty(leaf);
2481         inode_add_bytes(inode, len);
2482         btrfs_release_path(path);
2483
2484         ret = btrfs_inc_extent_ref(trans, root, new->bytenr,
2485                         new->disk_len, 0,
2486                         backref->root_id, backref->inum,
2487                         new->file_pos, 0);      /* start - extent_offset */
2488         if (ret) {
2489                 btrfs_abort_transaction(trans, root, ret);
2490                 goto out_free_path;
2491         }
2492
2493         ret = 1;
2494 out_free_path:
2495         btrfs_release_path(path);
2496         path->leave_spinning = 0;
2497         btrfs_end_transaction(trans, root);
2498 out_unlock:
2499         unlock_extent_cached(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2500                              &cached, GFP_NOFS);
2501         iput(inode);
2502         return ret;
2503 }
2504
2505 static void free_sa_defrag_extent(struct new_sa_defrag_extent *new)
2506 {
2507         struct old_sa_defrag_extent *old, *tmp;
2508
2509         if (!new)
2510                 return;
2511
2512         list_for_each_entry_safe(old, tmp, &new->head, list) {
2513                 list_del(&old->list);
2514                 kfree(old);
2515         }
2516         kfree(new);
2517 }
2518
2519 static void relink_file_extents(struct new_sa_defrag_extent *new)
2520 {
2521         struct btrfs_path *path;
2522         struct sa_defrag_extent_backref *backref;
2523         struct sa_defrag_extent_backref *prev = NULL;
2524         struct inode *inode;
2525         struct btrfs_root *root;
2526         struct rb_node *node;
2527         int ret;
2528
2529         inode = new->inode;
2530         root = BTRFS_I(inode)->root;
2531
2532         path = btrfs_alloc_path();
2533         if (!path)
2534                 return;
2535
2536         if (!record_extent_backrefs(path, new)) {
2537                 btrfs_free_path(path);
2538                 goto out;
2539         }
2540         btrfs_release_path(path);
2541
2542         while (1) {
2543                 node = rb_first(&new->root);
2544                 if (!node)
2545                         break;
2546                 rb_erase(node, &new->root);
2547
2548                 backref = rb_entry(node, struct sa_defrag_extent_backref, node);
2549
2550                 ret = relink_extent_backref(path, prev, backref);
2551                 WARN_ON(ret < 0);
2552
2553                 kfree(prev);
2554
2555                 if (ret == 1)
2556                         prev = backref;
2557                 else
2558                         prev = NULL;
2559                 cond_resched();
2560         }
2561         kfree(prev);
2562
2563         btrfs_free_path(path);
2564 out:
2565         free_sa_defrag_extent(new);
2566
2567         atomic_dec(&root->fs_info->defrag_running);
2568         wake_up(&root->fs_info->transaction_wait);
2569 }
2570
2571 static struct new_sa_defrag_extent *
2572 record_old_file_extents(struct inode *inode,
2573                         struct btrfs_ordered_extent *ordered)
2574 {
2575         struct btrfs_root *root = BTRFS_I(inode)->root;
2576         struct btrfs_path *path;
2577         struct btrfs_key key;
2578         struct old_sa_defrag_extent *old;
2579         struct new_sa_defrag_extent *new;
2580         int ret;
2581
2582         new = kmalloc(sizeof(*new), GFP_NOFS);
2583         if (!new)
2584                 return NULL;
2585
2586         new->inode = inode;
2587         new->file_pos = ordered->file_offset;
2588         new->len = ordered->len;
2589         new->bytenr = ordered->start;
2590         new->disk_len = ordered->disk_len;
2591         new->compress_type = ordered->compress_type;
2592         new->root = RB_ROOT;
2593         INIT_LIST_HEAD(&new->head);
2594
2595         path = btrfs_alloc_path();
2596         if (!path)
2597                 goto out_kfree;
2598
2599         key.objectid = btrfs_ino(inode);
2600         key.type = BTRFS_EXTENT_DATA_KEY;
2601         key.offset = new->file_pos;
2602
2603         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2604         if (ret < 0)
2605                 goto out_free_path;
2606         if (ret > 0 && path->slots[0] > 0)
2607                 path->slots[0]--;
2608
2609         /* find out all the old extents for the file range */
2610         while (1) {
2611                 struct btrfs_file_extent_item *extent;
2612                 struct extent_buffer *l;
2613                 int slot;
2614                 u64 num_bytes;
2615                 u64 offset;
2616                 u64 end;
2617                 u64 disk_bytenr;
2618                 u64 extent_offset;
2619
2620                 l = path->nodes[0];
2621                 slot = path->slots[0];
2622
2623                 if (slot >= btrfs_header_nritems(l)) {
2624                         ret = btrfs_next_leaf(root, path);
2625                         if (ret < 0)
2626                                 goto out_free_path;
2627                         else if (ret > 0)
2628                                 break;
2629                         continue;
2630                 }
2631
2632                 btrfs_item_key_to_cpu(l, &key, slot);
2633
2634                 if (key.objectid != btrfs_ino(inode))
2635                         break;
2636                 if (key.type != BTRFS_EXTENT_DATA_KEY)
2637                         break;
2638                 if (key.offset >= new->file_pos + new->len)
2639                         break;
2640
2641                 extent = btrfs_item_ptr(l, slot, struct btrfs_file_extent_item);
2642
2643                 num_bytes = btrfs_file_extent_num_bytes(l, extent);
2644                 if (key.offset + num_bytes < new->file_pos)
2645                         goto next;
2646
2647                 disk_bytenr = btrfs_file_extent_disk_bytenr(l, extent);
2648                 if (!disk_bytenr)
2649                         goto next;
2650
2651                 extent_offset = btrfs_file_extent_offset(l, extent);
2652
2653                 old = kmalloc(sizeof(*old), GFP_NOFS);
2654                 if (!old)
2655                         goto out_free_path;
2656
2657                 offset = max(new->file_pos, key.offset);
2658                 end = min(new->file_pos + new->len, key.offset + num_bytes);
2659
2660                 old->bytenr = disk_bytenr;
2661                 old->extent_offset = extent_offset;
2662                 old->offset = offset - key.offset;
2663                 old->len = end - offset;
2664                 old->new = new;
2665                 old->count = 0;
2666                 list_add_tail(&old->list, &new->head);
2667 next:
2668                 path->slots[0]++;
2669                 cond_resched();
2670         }
2671
2672         btrfs_free_path(path);
2673         atomic_inc(&root->fs_info->defrag_running);
2674
2675         return new;
2676
2677 out_free_path:
2678         btrfs_free_path(path);
2679 out_kfree:
2680         free_sa_defrag_extent(new);
2681         return NULL;
2682 }
2683
2684 static void btrfs_release_delalloc_bytes(struct btrfs_root *root,
2685                                          u64 start, u64 len)
2686 {
2687         struct btrfs_block_group_cache *cache;
2688
2689         cache = btrfs_lookup_block_group(root->fs_info, start);
2690         ASSERT(cache);
2691
2692         spin_lock(&cache->lock);
2693         cache->delalloc_bytes -= len;
2694         spin_unlock(&cache->lock);
2695
2696         btrfs_put_block_group(cache);
2697 }
2698
2699 /* as ordered data IO finishes, this gets called so we can finish
2700  * an ordered extent if the range of bytes in the file it covers are
2701  * fully written.
2702  */
2703 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
2704 {
2705         struct inode *inode = ordered_extent->inode;
2706         struct btrfs_root *root = BTRFS_I(inode)->root;
2707         struct btrfs_trans_handle *trans = NULL;
2708         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2709         struct extent_state *cached_state = NULL;
2710         struct new_sa_defrag_extent *new = NULL;
2711         int compress_type = 0;
2712         int ret = 0;
2713         u64 logical_len = ordered_extent->len;
2714         bool nolock;
2715         bool truncated = false;
2716
2717         nolock = btrfs_is_free_space_inode(inode);
2718
2719         if (test_bit(BTRFS_ORDERED_IOERR, &ordered_extent->flags)) {
2720                 ret = -EIO;
2721                 goto out;
2722         }
2723
2724         btrfs_free_io_failure_record(inode, ordered_extent->file_offset,
2725                                      ordered_extent->file_offset +
2726                                      ordered_extent->len - 1);
2727
2728         if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered_extent->flags)) {
2729                 truncated = true;
2730                 logical_len = ordered_extent->truncated_len;
2731                 /* Truncated the entire extent, don't bother adding */
2732                 if (!logical_len)
2733                         goto out;
2734         }
2735
2736         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {
2737                 BUG_ON(!list_empty(&ordered_extent->list)); /* Logic error */
2738                 btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2739                 if (nolock)
2740                         trans = btrfs_join_transaction_nolock(root);
2741                 else
2742                         trans = btrfs_join_transaction(root);
2743                 if (IS_ERR(trans)) {
2744                         ret = PTR_ERR(trans);
2745                         trans = NULL;
2746                         goto out;
2747                 }
2748                 trans->block_rsv = &root->fs_info->delalloc_block_rsv;
2749                 ret = btrfs_update_inode_fallback(trans, root, inode);
2750                 if (ret) /* -ENOMEM or corruption */
2751                         btrfs_abort_transaction(trans, root, ret);
2752                 goto out;
2753         }
2754
2755         lock_extent_bits(io_tree, ordered_extent->file_offset,
2756                          ordered_extent->file_offset + ordered_extent->len - 1,
2757                          0, &cached_state);
2758
2759         ret = test_range_bit(io_tree, ordered_extent->file_offset,
2760                         ordered_extent->file_offset + ordered_extent->len - 1,
2761                         EXTENT_DEFRAG, 1, cached_state);
2762         if (ret) {
2763                 u64 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
2764                 if (0 && last_snapshot >= BTRFS_I(inode)->generation)
2765                         /* the inode is shared */
2766                         new = record_old_file_extents(inode, ordered_extent);
2767
2768                 clear_extent_bit(io_tree, ordered_extent->file_offset,
2769                         ordered_extent->file_offset + ordered_extent->len - 1,
2770                         EXTENT_DEFRAG, 0, 0, &cached_state, GFP_NOFS);
2771         }
2772
2773         if (nolock)
2774                 trans = btrfs_join_transaction_nolock(root);
2775         else
2776                 trans = btrfs_join_transaction(root);
2777         if (IS_ERR(trans)) {
2778                 ret = PTR_ERR(trans);
2779                 trans = NULL;
2780                 goto out_unlock;
2781         }
2782
2783         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
2784
2785         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
2786                 compress_type = ordered_extent->compress_type;
2787         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
2788                 BUG_ON(compress_type);
2789                 ret = btrfs_mark_extent_written(trans, inode,
2790                                                 ordered_extent->file_offset,
2791                                                 ordered_extent->file_offset +
2792                                                 logical_len);
2793         } else {
2794                 BUG_ON(root == root->fs_info->tree_root);
2795                 ret = insert_reserved_file_extent(trans, inode,
2796                                                 ordered_extent->file_offset,
2797                                                 ordered_extent->start,
2798                                                 ordered_extent->disk_len,
2799                                                 logical_len, logical_len,
2800                                                 compress_type, 0, 0,
2801                                                 BTRFS_FILE_EXTENT_REG);
2802                 if (!ret)
2803                         btrfs_release_delalloc_bytes(root,
2804                                                      ordered_extent->start,
2805                                                      ordered_extent->disk_len);
2806         }
2807         unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
2808                            ordered_extent->file_offset, ordered_extent->len,
2809                            trans->transid);
2810         if (ret < 0) {
2811                 btrfs_abort_transaction(trans, root, ret);
2812                 goto out_unlock;
2813         }
2814
2815         add_pending_csums(trans, inode, ordered_extent->file_offset,
2816                           &ordered_extent->list);
2817
2818         btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2819         ret = btrfs_update_inode_fallback(trans, root, inode);
2820         if (ret) { /* -ENOMEM or corruption */
2821                 btrfs_abort_transaction(trans, root, ret);
2822                 goto out_unlock;
2823         }
2824         ret = 0;
2825 out_unlock:
2826         unlock_extent_cached(io_tree, ordered_extent->file_offset,
2827                              ordered_extent->file_offset +
2828                              ordered_extent->len - 1, &cached_state, GFP_NOFS);
2829 out:
2830         if (root != root->fs_info->tree_root)
2831                 btrfs_delalloc_release_metadata(inode, ordered_extent->len);
2832         if (trans)
2833                 btrfs_end_transaction(trans, root);
2834
2835         if (ret || truncated) {
2836                 u64 start, end;
2837
2838                 if (truncated)
2839                         start = ordered_extent->file_offset + logical_len;
2840                 else
2841                         start = ordered_extent->file_offset;
2842                 end = ordered_extent->file_offset + ordered_extent->len - 1;
2843                 clear_extent_uptodate(io_tree, start, end, NULL, GFP_NOFS);
2844
2845                 /* Drop the cache for the part of the extent we didn't write. */
2846                 btrfs_drop_extent_cache(inode, start, end, 0);
2847
2848                 /*
2849                  * If the ordered extent had an IOERR or something else went
2850                  * wrong we need to return the space for this ordered extent
2851                  * back to the allocator.  We only free the extent in the
2852                  * truncated case if we didn't write out the extent at all.
2853                  */
2854                 if ((ret || !logical_len) &&
2855                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags) &&
2856                     !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags))
2857                         btrfs_free_reserved_extent(root, ordered_extent->start,
2858                                                    ordered_extent->disk_len, 1);
2859         }
2860
2861
2862         /*
2863          * This needs to be done to make sure anybody waiting knows we are done
2864          * updating everything for this ordered extent.
2865          */
2866         btrfs_remove_ordered_extent(inode, ordered_extent);
2867
2868         /* for snapshot-aware defrag */
2869         if (new) {
2870                 if (ret) {
2871                         free_sa_defrag_extent(new);
2872                         atomic_dec(&root->fs_info->defrag_running);
2873                 } else {
2874                         relink_file_extents(new);
2875                 }
2876         }
2877
2878         /* once for us */
2879         btrfs_put_ordered_extent(ordered_extent);
2880         /* once for the tree */
2881         btrfs_put_ordered_extent(ordered_extent);
2882
2883         return ret;
2884 }
2885
2886 static void finish_ordered_fn(struct btrfs_work *work)
2887 {
2888         struct btrfs_ordered_extent *ordered_extent;
2889         ordered_extent = container_of(work, struct btrfs_ordered_extent, work);
2890         btrfs_finish_ordered_io(ordered_extent);
2891 }
2892
2893 static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
2894                                 struct extent_state *state, int uptodate)
2895 {
2896         struct inode *inode = page->mapping->host;
2897         struct btrfs_root *root = BTRFS_I(inode)->root;
2898         struct btrfs_ordered_extent *ordered_extent = NULL;
2899         struct btrfs_workqueue *wq;
2900         btrfs_work_func_t func;
2901
2902         trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);
2903
2904         ClearPagePrivate2(page);
2905         if (!btrfs_dec_test_ordered_pending(inode, &ordered_extent, start,
2906                                             end - start + 1, uptodate))
2907                 return 0;
2908
2909         if (btrfs_is_free_space_inode(inode)) {
2910                 wq = root->fs_info->endio_freespace_worker;
2911                 func = btrfs_freespace_write_helper;
2912         } else {
2913                 wq = root->fs_info->endio_write_workers;
2914                 func = btrfs_endio_write_helper;
2915         }
2916
2917         btrfs_init_work(&ordered_extent->work, func, finish_ordered_fn, NULL,
2918                         NULL);
2919         btrfs_queue_work(wq, &ordered_extent->work);
2920
2921         return 0;
2922 }
2923
2924 static int __readpage_endio_check(struct inode *inode,
2925                                   struct btrfs_io_bio *io_bio,
2926                                   int icsum, struct page *page,
2927                                   int pgoff, u64 start, size_t len)
2928 {
2929         char *kaddr;
2930         u32 csum_expected;
2931         u32 csum = ~(u32)0;
2932         static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL,
2933                                       DEFAULT_RATELIMIT_BURST);
2934
2935         csum_expected = *(((u32 *)io_bio->csum) + icsum);
2936
2937         kaddr = kmap_atomic(page);
2938         csum = btrfs_csum_data(kaddr + pgoff, csum,  len);
2939         btrfs_csum_final(csum, (char *)&csum);
2940         if (csum != csum_expected)
2941                 goto zeroit;
2942
2943         kunmap_atomic(kaddr);
2944         return 0;
2945 zeroit:
2946         if (__ratelimit(&_rs))
2947                 btrfs_info(BTRFS_I(inode)->root->fs_info,
2948                            "csum failed ino %llu off %llu csum %u expected csum %u",
2949                            btrfs_ino(inode), start, csum, csum_expected);
2950         memset(kaddr + pgoff, 1, len);
2951         flush_dcache_page(page);
2952         kunmap_atomic(kaddr);
2953         if (csum_expected == 0)
2954                 return 0;
2955         return -EIO;
2956 }
2957
2958 /*
2959  * when reads are done, we need to check csums to verify the data is correct
2960  * if there's a match, we allow the bio to finish.  If not, the code in
2961  * extent_io.c will try to find good copies for us.
2962  */
2963 static int btrfs_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
2964                                       u64 phy_offset, struct page *page,
2965                                       u64 start, u64 end, int mirror)
2966 {
2967         size_t offset = start - page_offset(page);
2968         struct inode *inode = page->mapping->host;
2969         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2970         struct btrfs_root *root = BTRFS_I(inode)->root;
2971
2972         if (PageChecked(page)) {
2973                 ClearPageChecked(page);
2974                 return 0;
2975         }
2976
2977         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
2978                 return 0;
2979
2980         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
2981             test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
2982                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM,
2983                                   GFP_NOFS);
2984                 return 0;
2985         }
2986
2987         phy_offset >>= inode->i_sb->s_blocksize_bits;
2988         return __readpage_endio_check(inode, io_bio, phy_offset, page, offset,
2989                                       start, (size_t)(end - start + 1));
2990 }
2991
2992 struct delayed_iput {
2993         struct list_head list;
2994         struct inode *inode;
2995 };
2996
2997 /* JDM: If this is fs-wide, why can't we add a pointer to
2998  * btrfs_inode instead and avoid the allocation? */
2999 void btrfs_add_delayed_iput(struct inode *inode)
3000 {
3001         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
3002         struct delayed_iput *delayed;
3003
3004         if (atomic_add_unless(&inode->i_count, -1, 1))
3005                 return;
3006
3007         delayed = kmalloc(sizeof(*delayed), GFP_NOFS | __GFP_NOFAIL);
3008         delayed->inode = inode;
3009
3010         spin_lock(&fs_info->delayed_iput_lock);
3011         list_add_tail(&delayed->list, &fs_info->delayed_iputs);
3012         spin_unlock(&fs_info->delayed_iput_lock);
3013 }
3014
3015 void btrfs_run_delayed_iputs(struct btrfs_root *root)
3016 {
3017         LIST_HEAD(list);
3018         struct btrfs_fs_info *fs_info = root->fs_info;
3019         struct delayed_iput *delayed;
3020         int empty;
3021
3022         spin_lock(&fs_info->delayed_iput_lock);
3023         empty = list_empty(&fs_info->delayed_iputs);
3024         spin_unlock(&fs_info->delayed_iput_lock);
3025         if (empty)
3026                 return;
3027
3028         spin_lock(&fs_info->delayed_iput_lock);
3029         list_splice_init(&fs_info->delayed_iputs, &list);
3030         spin_unlock(&fs_info->delayed_iput_lock);
3031
3032         while (!list_empty(&list)) {
3033                 delayed = list_entry(list.next, struct delayed_iput, list);
3034                 list_del(&delayed->list);
3035                 iput(delayed->inode);
3036                 kfree(delayed);
3037         }
3038 }
3039
3040 /*
3041  * This is called in transaction commit time. If there are no orphan
3042  * files in the subvolume, it removes orphan item and frees block_rsv
3043  * structure.
3044  */
3045 void btrfs_orphan_commit_root(struct btrfs_trans_handle *trans,
3046                               struct btrfs_root *root)
3047 {
3048         struct btrfs_block_rsv *block_rsv;
3049         int ret;
3050
3051         if (atomic_read(&root->orphan_inodes) ||
3052             root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE)
3053                 return;
3054
3055         spin_lock(&root->orphan_lock);
3056         if (atomic_read(&root->orphan_inodes)) {
3057                 spin_unlock(&root->orphan_lock);
3058                 return;
3059         }
3060
3061         if (root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE) {
3062                 spin_unlock(&root->orphan_lock);
3063                 return;
3064         }
3065
3066         block_rsv = root->orphan_block_rsv;
3067         root->orphan_block_rsv = NULL;
3068         spin_unlock(&root->orphan_lock);
3069
3070         if (test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state) &&
3071             btrfs_root_refs(&root->root_item) > 0) {
3072                 ret = btrfs_del_orphan_item(trans, root->fs_info->tree_root,
3073                                             root->root_key.objectid);
3074                 if (ret)
3075                         btrfs_abort_transaction(trans, root, ret);
3076                 else
3077                         clear_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED,
3078                                   &root->state);
3079         }
3080
3081         if (block_rsv) {
3082                 WARN_ON(block_rsv->size > 0);
3083                 btrfs_free_block_rsv(root, block_rsv);
3084         }
3085 }
3086
3087 /*
3088  * This creates an orphan entry for the given inode in case something goes
3089  * wrong in the middle of an unlink/truncate.
3090  *
3091  * NOTE: caller of this function should reserve 5 units of metadata for
3092  *       this function.
3093  */
3094 int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
3095 {
3096         struct btrfs_root *root = BTRFS_I(inode)->root;
3097         struct btrfs_block_rsv *block_rsv = NULL;
3098         int reserve = 0;
3099         int insert = 0;
3100         int ret;
3101
3102         if (!root->orphan_block_rsv) {
3103                 block_rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
3104                 if (!block_rsv)
3105                         return -ENOMEM;
3106         }
3107
3108         spin_lock(&root->orphan_lock);
3109         if (!root->orphan_block_rsv) {
3110                 root->orphan_block_rsv = block_rsv;
3111         } else if (block_rsv) {
3112                 btrfs_free_block_rsv(root, block_rsv);
3113                 block_rsv = NULL;
3114         }
3115
3116         if (!test_and_set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3117                               &BTRFS_I(inode)->runtime_flags)) {
3118 #if 0
3119                 /*
3120                  * For proper ENOSPC handling, we should do orphan
3121                  * cleanup when mounting. But this introduces backward
3122                  * compatibility issue.
3123                  */
3124                 if (!xchg(&root->orphan_item_inserted, 1))
3125                         insert = 2;
3126                 else
3127                         insert = 1;
3128 #endif
3129                 insert = 1;
3130                 atomic_inc(&root->orphan_inodes);
3131         }
3132
3133         if (!test_and_set_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3134                               &BTRFS_I(inode)->runtime_flags))
3135                 reserve = 1;
3136         spin_unlock(&root->orphan_lock);
3137
3138         /* grab metadata reservation from transaction handle */
3139         if (reserve) {
3140                 ret = btrfs_orphan_reserve_metadata(trans, inode);
3141                 BUG_ON(ret); /* -ENOSPC in reservation; Logic error? JDM */
3142         }
3143
3144         /* insert an orphan item to track this unlinked/truncated file */
3145         if (insert >= 1) {
3146                 ret = btrfs_insert_orphan_item(trans, root, btrfs_ino(inode));
3147                 if (ret) {
3148                         atomic_dec(&root->orphan_inodes);
3149                         if (reserve) {
3150                                 clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3151                                           &BTRFS_I(inode)->runtime_flags);
3152                                 btrfs_orphan_release_metadata(inode);
3153                         }
3154                         if (ret != -EEXIST) {
3155                                 clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3156                                           &BTRFS_I(inode)->runtime_flags);
3157                                 btrfs_abort_transaction(trans, root, ret);
3158                                 return ret;
3159                         }
3160                 }
3161                 ret = 0;
3162         }
3163
3164         /* insert an orphan item to track subvolume contains orphan files */
3165         if (insert >= 2) {
3166                 ret = btrfs_insert_orphan_item(trans, root->fs_info->tree_root,
3167                                                root->root_key.objectid);
3168                 if (ret && ret != -EEXIST) {
3169                         btrfs_abort_transaction(trans, root, ret);
3170                         return ret;
3171                 }
3172         }
3173         return 0;
3174 }
3175
3176 /*
3177  * We have done the truncate/delete so we can go ahead and remove the orphan
3178  * item for this particular inode.
3179  */
3180 static int btrfs_orphan_del(struct btrfs_trans_handle *trans,
3181                             struct inode *inode)
3182 {
3183         struct btrfs_root *root = BTRFS_I(inode)->root;
3184         int delete_item = 0;
3185         int release_rsv = 0;
3186         int ret = 0;
3187
3188         spin_lock(&root->orphan_lock);
3189         if (test_and_clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3190                                &BTRFS_I(inode)->runtime_flags))
3191                 delete_item = 1;
3192
3193         if (test_and_clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3194                                &BTRFS_I(inode)->runtime_flags))
3195                 release_rsv = 1;
3196         spin_unlock(&root->orphan_lock);
3197
3198         if (delete_item) {
3199                 atomic_dec(&root->orphan_inodes);
3200                 if (trans)
3201                         ret = btrfs_del_orphan_item(trans, root,
3202                                                     btrfs_ino(inode));
3203         }
3204
3205         if (release_rsv)
3206                 btrfs_orphan_release_metadata(inode);
3207
3208         return ret;
3209 }
3210
3211 /*
3212  * this cleans up any orphans that may be left on the list from the last use
3213  * of this root.
3214  */
3215 int btrfs_orphan_cleanup(struct btrfs_root *root)
3216 {
3217         struct btrfs_path *path;
3218         struct extent_buffer *leaf;
3219         struct btrfs_key key, found_key;
3220         struct btrfs_trans_handle *trans;
3221         struct inode *inode;
3222         u64 last_objectid = 0;
3223         int ret = 0, nr_unlink = 0, nr_truncate = 0;
3224
3225         if (cmpxchg(&root->orphan_cleanup_state, 0, ORPHAN_CLEANUP_STARTED))
3226                 return 0;
3227
3228         path = btrfs_alloc_path();
3229         if (!path) {
3230                 ret = -ENOMEM;
3231                 goto out;
3232         }
3233         path->reada = -1;
3234
3235         key.objectid = BTRFS_ORPHAN_OBJECTID;
3236         key.type = BTRFS_ORPHAN_ITEM_KEY;
3237         key.offset = (u64)-1;
3238
3239         while (1) {
3240                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3241                 if (ret < 0)
3242                         goto out;
3243
3244                 /*
3245                  * if ret == 0 means we found what we were searching for, which
3246                  * is weird, but possible, so only screw with path if we didn't
3247                  * find the key and see if we have stuff that matches
3248                  */
3249                 if (ret > 0) {
3250                         ret = 0;
3251                         if (path->slots[0] == 0)
3252                                 break;
3253                         path->slots[0]--;
3254                 }
3255
3256                 /* pull out the item */
3257                 leaf = path->nodes[0];
3258                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3259
3260                 /* make sure the item matches what we want */
3261                 if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
3262                         break;
3263                 if (found_key.type != BTRFS_ORPHAN_ITEM_KEY)
3264                         break;
3265
3266                 /* release the path since we're done with it */
3267                 btrfs_release_path(path);
3268
3269                 /*
3270                  * this is where we are basically btrfs_lookup, without the
3271                  * crossing root thing.  we store the inode number in the
3272                  * offset of the orphan item.
3273                  */
3274
3275                 if (found_key.offset == last_objectid) {
3276                         btrfs_err(root->fs_info,
3277                                 "Error removing orphan entry, stopping orphan cleanup");
3278                         ret = -EINVAL;
3279                         goto out;
3280                 }
3281
3282                 last_objectid = found_key.offset;
3283
3284                 found_key.objectid = found_key.offset;
3285                 found_key.type = BTRFS_INODE_ITEM_KEY;
3286                 found_key.offset = 0;
3287                 inode = btrfs_iget(root->fs_info->sb, &found_key, root, NULL);
3288                 ret = PTR_ERR_OR_ZERO(inode);
3289                 if (ret && ret != -ESTALE)
3290                         goto out;
3291
3292                 if (ret == -ESTALE && root == root->fs_info->tree_root) {
3293                         struct btrfs_root *dead_root;
3294                         struct btrfs_fs_info *fs_info = root->fs_info;
3295                         int is_dead_root = 0;
3296
3297                         /*
3298                          * this is an orphan in the tree root. Currently these
3299                          * could come from 2 sources:
3300                          *  a) a snapshot deletion in progress
3301                          *  b) a free space cache inode
3302                          * We need to distinguish those two, as the snapshot
3303                          * orphan must not get deleted.
3304                          * find_dead_roots already ran before us, so if this
3305                          * is a snapshot deletion, we should find the root
3306                          * in the dead_roots list
3307                          */
3308                         spin_lock(&fs_info->trans_lock);
3309                         list_for_each_entry(dead_root, &fs_info->dead_roots,
3310                                             root_list) {
3311                                 if (dead_root->root_key.objectid ==
3312                                     found_key.objectid) {
3313                                         is_dead_root = 1;
3314                                         break;
3315                                 }
3316                         }
3317                         spin_unlock(&fs_info->trans_lock);
3318                         if (is_dead_root) {
3319                                 /* prevent this orphan from being found again */
3320                                 key.offset = found_key.objectid - 1;
3321                                 continue;
3322                         }
3323                 }
3324                 /*
3325                  * Inode is already gone but the orphan item is still there,
3326                  * kill the orphan item.
3327                  */
3328                 if (ret == -ESTALE) {
3329                         trans = btrfs_start_transaction(root, 1);
3330                         if (IS_ERR(trans)) {
3331                                 ret = PTR_ERR(trans);
3332                                 goto out;
3333                         }
3334                         btrfs_debug(root->fs_info, "auto deleting %Lu",
3335                                 found_key.objectid);
3336                         ret = btrfs_del_orphan_item(trans, root,
3337                                                     found_key.objectid);
3338                         btrfs_end_transaction(trans, root);
3339                         if (ret)
3340                                 goto out;
3341                         continue;
3342                 }
3343
3344                 /*
3345                  * add this inode to the orphan list so btrfs_orphan_del does
3346                  * the proper thing when we hit it
3347                  */
3348                 set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3349                         &BTRFS_I(inode)->runtime_flags);
3350                 atomic_inc(&root->orphan_inodes);
3351
3352                 /* if we have links, this was a truncate, lets do that */
3353                 if (inode->i_nlink) {
3354                         if (WARN_ON(!S_ISREG(inode->i_mode))) {
3355                                 iput(inode);
3356                                 continue;
3357                         }
3358                         nr_truncate++;
3359
3360                         /* 1 for the orphan item deletion. */
3361                         trans = btrfs_start_transaction(root, 1);
3362                         if (IS_ERR(trans)) {
3363                                 iput(inode);
3364                                 ret = PTR_ERR(trans);
3365                                 goto out;
3366                         }
3367                         ret = btrfs_orphan_add(trans, inode);
3368                         btrfs_end_transaction(trans, root);
3369                         if (ret) {
3370                                 iput(inode);
3371                                 goto out;
3372                         }
3373
3374                         ret = btrfs_truncate(inode);
3375                         if (ret)
3376                                 btrfs_orphan_del(NULL, inode);
3377                 } else {
3378                         nr_unlink++;
3379                 }
3380
3381                 /* this will do delete_inode and everything for us */
3382                 iput(inode);
3383                 if (ret)
3384                         goto out;
3385         }
3386         /* release the path since we're done with it */
3387         btrfs_release_path(path);
3388
3389         root->orphan_cleanup_state = ORPHAN_CLEANUP_DONE;
3390
3391         if (root->orphan_block_rsv)
3392                 btrfs_block_rsv_release(root, root->orphan_block_rsv,
3393                                         (u64)-1);
3394
3395         if (root->orphan_block_rsv ||
3396             test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state)) {
3397                 trans = btrfs_join_transaction(root);
3398                 if (!IS_ERR(trans))
3399                         btrfs_end_transaction(trans, root);
3400         }
3401
3402         if (nr_unlink)
3403                 btrfs_debug(root->fs_info, "unlinked %d orphans", nr_unlink);
3404         if (nr_truncate)
3405                 btrfs_debug(root->fs_info, "truncated %d orphans", nr_truncate);
3406
3407 out:
3408         if (ret)
3409                 btrfs_crit(root->fs_info,
3410                         "could not do orphan cleanup %d", ret);
3411         btrfs_free_path(path);
3412         return ret;
3413 }
3414
3415 /*
3416  * very simple check to peek ahead in the leaf looking for xattrs.  If we
3417  * don't find any xattrs, we know there can't be any acls.
3418  *
3419  * slot is the slot the inode is in, objectid is the objectid of the inode
3420  */
3421 static noinline int acls_after_inode_item(struct extent_buffer *leaf,
3422                                           int slot, u64 objectid,
3423                                           int *first_xattr_slot)
3424 {
3425         u32 nritems = btrfs_header_nritems(leaf);
3426         struct btrfs_key found_key;
3427         static u64 xattr_access = 0;
3428         static u64 xattr_default = 0;
3429         int scanned = 0;
3430
3431         if (!xattr_access) {
3432                 xattr_access = btrfs_name_hash(POSIX_ACL_XATTR_ACCESS,
3433                                         strlen(POSIX_ACL_XATTR_ACCESS));
3434                 xattr_default = btrfs_name_hash(POSIX_ACL_XATTR_DEFAULT,
3435                                         strlen(POSIX_ACL_XATTR_DEFAULT));
3436         }
3437
3438         slot++;
3439         *first_xattr_slot = -1;
3440         while (slot < nritems) {
3441                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3442
3443                 /* we found a different objectid, there must not be acls */
3444                 if (found_key.objectid != objectid)
3445                         return 0;
3446
3447                 /* we found an xattr, assume we've got an acl */
3448                 if (found_key.type == BTRFS_XATTR_ITEM_KEY) {
3449                         if (*first_xattr_slot == -1)
3450                                 *first_xattr_slot = slot;
3451                         if (found_key.offset == xattr_access ||
3452                             found_key.offset == xattr_default)
3453                                 return 1;
3454                 }
3455
3456                 /*
3457                  * we found a key greater than an xattr key, there can't
3458                  * be any acls later on
3459                  */
3460                 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
3461                         return 0;
3462
3463                 slot++;
3464                 scanned++;
3465
3466                 /*
3467                  * it goes inode, inode backrefs, xattrs, extents,
3468                  * so if there are a ton of hard links to an inode there can
3469                  * be a lot of backrefs.  Don't waste time searching too hard,
3470                  * this is just an optimization
3471                  */
3472                 if (scanned >= 8)
3473                         break;
3474         }
3475         /* we hit the end of the leaf before we found an xattr or
3476          * something larger than an xattr.  We have to assume the inode
3477          * has acls
3478          */
3479         if (*first_xattr_slot == -1)
3480                 *first_xattr_slot = slot;
3481         return 1;
3482 }
3483
3484 /*
3485  * read an inode from the btree into the in-memory inode
3486  */
3487 static void btrfs_read_locked_inode(struct inode *inode)
3488 {
3489         struct btrfs_path *path;
3490         struct extent_buffer *leaf;
3491         struct btrfs_inode_item *inode_item;
3492         struct btrfs_timespec *tspec;
3493         struct btrfs_root *root = BTRFS_I(inode)->root;
3494         struct btrfs_key location;
3495         unsigned long ptr;
3496         int maybe_acls;
3497         u32 rdev;
3498         int ret;
3499         bool filled = false;
3500         int first_xattr_slot;
3501
3502         ret = btrfs_fill_inode(inode, &rdev);
3503         if (!ret)
3504                 filled = true;
3505
3506         path = btrfs_alloc_path();
3507         if (!path)
3508                 goto make_bad;
3509
3510         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
3511
3512         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
3513         if (ret)
3514                 goto make_bad;
3515
3516         leaf = path->nodes[0];
3517
3518         if (filled)
3519                 goto cache_index;
3520
3521         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3522                                     struct btrfs_inode_item);
3523         inode->i_mode = btrfs_inode_mode(leaf, inode_item);
3524         set_nlink(inode, btrfs_inode_nlink(leaf, inode_item));
3525         i_uid_write(inode, btrfs_inode_uid(leaf, inode_item));
3526         i_gid_write(inode, btrfs_inode_gid(leaf, inode_item));
3527         btrfs_i_size_write(inode, btrfs_inode_size(leaf, inode_item));
3528
3529         tspec = btrfs_inode_atime(inode_item);
3530         inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, tspec);
3531         inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
3532
3533         tspec = btrfs_inode_mtime(inode_item);
3534         inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, tspec);
3535         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
3536
3537         tspec = btrfs_inode_ctime(inode_item);
3538         inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, tspec);
3539         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
3540
3541         inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
3542         BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
3543         BTRFS_I(inode)->last_trans = btrfs_inode_transid(leaf, inode_item);
3544
3545         /*
3546          * If we were modified in the current generation and evicted from memory
3547          * and then re-read we need to do a full sync since we don't have any
3548          * idea about which extents were modified before we were evicted from
3549          * cache.
3550          */
3551         if (BTRFS_I(inode)->last_trans == root->fs_info->generation)
3552                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
3553                         &BTRFS_I(inode)->runtime_flags);
3554
3555         inode->i_version = btrfs_inode_sequence(leaf, inode_item);
3556         inode->i_generation = BTRFS_I(inode)->generation;
3557         inode->i_rdev = 0;
3558         rdev = btrfs_inode_rdev(leaf, inode_item);
3559
3560         BTRFS_I(inode)->index_cnt = (u64)-1;
3561         BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
3562
3563 cache_index:
3564         path->slots[0]++;
3565         if (inode->i_nlink != 1 ||
3566             path->slots[0] >= btrfs_header_nritems(leaf))
3567                 goto cache_acl;
3568
3569         btrfs_item_key_to_cpu(leaf, &location, path->slots[0]);
3570         if (location.objectid != btrfs_ino(inode))
3571                 goto cache_acl;
3572
3573         ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
3574         if (location.type == BTRFS_INODE_REF_KEY) {
3575                 struct btrfs_inode_ref *ref;
3576
3577                 ref = (struct btrfs_inode_ref *)ptr;
3578                 BTRFS_I(inode)->dir_index = btrfs_inode_ref_index(leaf, ref);
3579         } else if (location.type == BTRFS_INODE_EXTREF_KEY) {
3580                 struct btrfs_inode_extref *extref;
3581
3582                 extref = (struct btrfs_inode_extref *)ptr;
3583                 BTRFS_I(inode)->dir_index = btrfs_inode_extref_index(leaf,
3584                                                                      extref);
3585         }
3586 cache_acl:
3587         /*
3588          * try to precache a NULL acl entry for files that don't have
3589          * any xattrs or acls
3590          */
3591         maybe_acls = acls_after_inode_item(leaf, path->slots[0],
3592                                            btrfs_ino(inode), &first_xattr_slot);
3593         if (first_xattr_slot != -1) {
3594                 path->slots[0] = first_xattr_slot;
3595                 ret = btrfs_load_inode_props(inode, path);
3596                 if (ret)
3597                         btrfs_err(root->fs_info,
3598                                   "error loading props for ino %llu (root %llu): %d",
3599                                   btrfs_ino(inode),
3600                                   root->root_key.objectid, ret);
3601         }
3602         btrfs_free_path(path);
3603
3604         if (!maybe_acls)
3605                 cache_no_acl(inode);
3606
3607         switch (inode->i_mode & S_IFMT) {
3608         case S_IFREG:
3609                 inode->i_mapping->a_ops = &btrfs_aops;
3610                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
3611                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
3612                 inode->i_fop = &btrfs_file_operations;
3613                 inode->i_op = &btrfs_file_inode_operations;
3614                 break;
3615         case S_IFDIR:
3616                 inode->i_fop = &btrfs_dir_file_operations;
3617                 if (root == root->fs_info->tree_root)
3618                         inode->i_op = &btrfs_dir_ro_inode_operations;
3619                 else
3620                         inode->i_op = &btrfs_dir_inode_operations;
3621                 break;
3622         case S_IFLNK:
3623                 inode->i_op = &btrfs_symlink_inode_operations;
3624                 inode->i_mapping->a_ops = &btrfs_symlink_aops;
3625                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
3626                 break;
3627         default:
3628                 inode->i_op = &btrfs_special_inode_operations;
3629                 init_special_inode(inode, inode->i_mode, rdev);
3630                 break;
3631         }
3632
3633         btrfs_update_iflags(inode);
3634         return;
3635
3636 make_bad:
3637         btrfs_free_path(path);
3638         make_bad_inode(inode);
3639 }
3640
3641 /*
3642  * given a leaf and an inode, copy the inode fields into the leaf
3643  */
3644 static void fill_inode_item(struct btrfs_trans_handle *trans,
3645                             struct extent_buffer *leaf,
3646                             struct btrfs_inode_item *item,
3647                             struct inode *inode)
3648 {
3649         struct btrfs_map_token token;
3650
3651         btrfs_init_map_token(&token);
3652
3653         btrfs_set_token_inode_uid(leaf, item, i_uid_read(inode), &token);
3654         btrfs_set_token_inode_gid(leaf, item, i_gid_read(inode), &token);
3655         btrfs_set_token_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size,
3656                                    &token);
3657         btrfs_set_token_inode_mode(leaf, item, inode->i_mode, &token);
3658         btrfs_set_token_inode_nlink(leaf, item, inode->i_nlink, &token);
3659
3660         btrfs_set_token_timespec_sec(leaf, btrfs_inode_atime(item),
3661                                      inode->i_atime.tv_sec, &token);
3662         btrfs_set_token_timespec_nsec(leaf, btrfs_inode_atime(item),
3663                                       inode->i_atime.tv_nsec, &token);
3664
3665         btrfs_set_token_timespec_sec(leaf, btrfs_inode_mtime(item),
3666                                      inode->i_mtime.tv_sec, &token);
3667         btrfs_set_token_timespec_nsec(leaf, btrfs_inode_mtime(item),
3668                                       inode->i_mtime.tv_nsec, &token);
3669
3670         btrfs_set_token_timespec_sec(leaf, btrfs_inode_ctime(item),
3671                                      inode->i_ctime.tv_sec, &token);
3672         btrfs_set_token_timespec_nsec(leaf, btrfs_inode_ctime(item),
3673                                       inode->i_ctime.tv_nsec, &token);
3674
3675         btrfs_set_token_inode_nbytes(leaf, item, inode_get_bytes(inode),
3676                                      &token);
3677         btrfs_set_token_inode_generation(leaf, item, BTRFS_I(inode)->generation,
3678                                          &token);
3679         btrfs_set_token_inode_sequence(leaf, item, inode->i_version, &token);
3680         btrfs_set_token_inode_transid(leaf, item, trans->transid, &token);
3681         btrfs_set_token_inode_rdev(leaf, item, inode->i_rdev, &token);
3682         btrfs_set_token_inode_flags(leaf, item, BTRFS_I(inode)->flags, &token);
3683         btrfs_set_token_inode_block_group(leaf, item, 0, &token);
3684 }
3685
3686 /*
3687  * copy everything in the in-memory inode into the btree.
3688  */
3689 static noinline int btrfs_update_inode_item(struct btrfs_trans_handle *trans,
3690                                 struct btrfs_root *root, struct inode *inode)
3691 {
3692         struct btrfs_inode_item *inode_item;
3693         struct btrfs_path *path;
3694         struct extent_buffer *leaf;
3695         int ret;
3696
3697         path = btrfs_alloc_path();
3698         if (!path)
3699                 return -ENOMEM;
3700
3701         path->leave_spinning = 1;
3702         ret = btrfs_lookup_inode(trans, root, path, &BTRFS_I(inode)->location,
3703                                  1);
3704         if (ret) {
3705                 if (ret > 0)
3706                         ret = -ENOENT;
3707                 goto failed;
3708         }
3709
3710         leaf = path->nodes[0];
3711         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3712                                     struct btrfs_inode_item);
3713
3714         fill_inode_item(trans, leaf, inode_item, inode);
3715         btrfs_mark_buffer_dirty(leaf);
3716         btrfs_set_inode_last_trans(trans, inode);
3717         ret = 0;
3718 failed:
3719         btrfs_free_path(path);
3720         return ret;
3721 }
3722
3723 /*
3724  * copy everything in the in-memory inode into the btree.
3725  */
3726 noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
3727                                 struct btrfs_root *root, struct inode *inode)
3728 {
3729         int ret;
3730
3731         /*
3732          * If the inode is a free space inode, we can deadlock during commit
3733          * if we put it into the delayed code.
3734          *
3735          * The data relocation inode should also be directly updated
3736          * without delay
3737          */
3738         if (!btrfs_is_free_space_inode(inode)
3739             && root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
3740             && !root->fs_info->log_root_recovering) {
3741                 btrfs_update_root_times(trans, root);
3742
3743                 ret = btrfs_delayed_update_inode(trans, root, inode);
3744                 if (!ret)
3745                         btrfs_set_inode_last_trans(trans, inode);
3746                 return ret;
3747         }
3748
3749         return btrfs_update_inode_item(trans, root, inode);
3750 }
3751
3752 noinline int btrfs_update_inode_fallback(struct btrfs_trans_handle *trans,
3753                                          struct btrfs_root *root,
3754                                          struct inode *inode)
3755 {
3756         int ret;
3757
3758         ret = btrfs_update_inode(trans, root, inode);
3759         if (ret == -ENOSPC)
3760                 return btrfs_update_inode_item(trans, root, inode);
3761         return ret;
3762 }
3763
3764 /*
3765  * unlink helper that gets used here in inode.c and in the tree logging
3766  * recovery code.  It remove a link in a directory with a given name, and
3767  * also drops the back refs in the inode to the directory
3768  */
3769 static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3770                                 struct btrfs_root *root,
3771                                 struct inode *dir, struct inode *inode,
3772                                 const char *name, int name_len)
3773 {
3774         struct btrfs_path *path;
3775         int ret = 0;
3776         struct extent_buffer *leaf;
3777         struct btrfs_dir_item *di;
3778         struct btrfs_key key;
3779         u64 index;
3780         u64 ino = btrfs_ino(inode);
3781         u64 dir_ino = btrfs_ino(dir);
3782
3783         path = btrfs_alloc_path();
3784         if (!path) {
3785                 ret = -ENOMEM;
3786                 goto out;
3787         }
3788
3789         path->leave_spinning = 1;
3790         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3791                                     name, name_len, -1);
3792         if (IS_ERR(di)) {
3793                 ret = PTR_ERR(di);
3794                 goto err;
3795         }
3796         if (!di) {
3797                 ret = -ENOENT;
3798                 goto err;
3799         }
3800         leaf = path->nodes[0];
3801         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3802         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3803         if (ret)
3804                 goto err;
3805         btrfs_release_path(path);
3806
3807         /*
3808          * If we don't have dir index, we have to get it by looking up
3809          * the inode ref, since we get the inode ref, remove it directly,
3810          * it is unnecessary to do delayed deletion.
3811          *
3812          * But if we have dir index, needn't search inode ref to get it.
3813          * Since the inode ref is close to the inode item, it is better
3814          * that we delay to delete it, and just do this deletion when
3815          * we update the inode item.
3816          */
3817         if (BTRFS_I(inode)->dir_index) {
3818                 ret = btrfs_delayed_delete_inode_ref(inode);
3819                 if (!ret) {
3820                         index = BTRFS_I(inode)->dir_index;
3821                         goto skip_backref;
3822                 }
3823         }
3824
3825         ret = btrfs_del_inode_ref(trans, root, name, name_len, ino,
3826                                   dir_ino, &index);
3827         if (ret) {
3828                 btrfs_info(root->fs_info,
3829                         "failed to delete reference to %.*s, inode %llu parent %llu",
3830                         name_len, name, ino, dir_ino);
3831                 btrfs_abort_transaction(trans, root, ret);
3832                 goto err;
3833         }
3834 skip_backref:
3835         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
3836         if (ret) {
3837                 btrfs_abort_transaction(trans, root, ret);
3838                 goto err;
3839         }
3840
3841         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len,
3842                                          inode, dir_ino);
3843         if (ret != 0 && ret != -ENOENT) {
3844                 btrfs_abort_transaction(trans, root, ret);
3845                 goto err;
3846         }
3847
3848         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len,
3849                                            dir, index);
3850         if (ret == -ENOENT)
3851                 ret = 0;
3852         else if (ret)
3853                 btrfs_abort_transaction(trans, root, ret);
3854 err:
3855         btrfs_free_path(path);
3856         if (ret)
3857                 goto out;
3858
3859         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
3860         inode_inc_iversion(inode);
3861         inode_inc_iversion(dir);
3862         inode->i_ctime = dir->i_mtime = dir->i_ctime = CURRENT_TIME;
3863         ret = btrfs_update_inode(trans, root, dir);
3864 out:
3865         return ret;
3866 }
3867
3868 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3869                        struct btrfs_root *root,
3870                        struct inode *dir, struct inode *inode,
3871                        const char *name, int name_len)
3872 {
3873         int ret;
3874         ret = __btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
3875         if (!ret) {
3876                 drop_nlink(inode);
3877                 ret = btrfs_update_inode(trans, root, inode);
3878         }
3879         return ret;
3880 }
3881
3882 /*
3883  * helper to start transaction for unlink and rmdir.
3884  *
3885  * unlink and rmdir are special in btrfs, they do not always free space, so
3886  * if we cannot make our reservations the normal way try and see if there is
3887  * plenty of slack room in the global reserve to migrate, otherwise we cannot
3888  * allow the unlink to occur.
3889  */
3890 static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir)
3891 {
3892         struct btrfs_trans_handle *trans;
3893         struct btrfs_root *root = BTRFS_I(dir)->root;
3894         int ret;
3895
3896         /*
3897          * 1 for the possible orphan item
3898          * 1 for the dir item
3899          * 1 for the dir index
3900          * 1 for the inode ref
3901          * 1 for the inode
3902          */
3903         trans = btrfs_start_transaction(root, 5);
3904         if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC)
3905                 return trans;
3906
3907         if (PTR_ERR(trans) == -ENOSPC) {
3908                 u64 num_bytes = btrfs_calc_trans_metadata_size(root, 5);
3909
3910                 trans = btrfs_start_transaction(root, 0);
3911                 if (IS_ERR(trans))
3912                         return trans;
3913                 ret = btrfs_cond_migrate_bytes(root->fs_info,
3914                                                &root->fs_info->trans_block_rsv,
3915                                                num_bytes, 5);
3916                 if (ret) {
3917                         btrfs_end_transaction(trans, root);
3918                         return ERR_PTR(ret);
3919                 }
3920                 trans->block_rsv = &root->fs_info->trans_block_rsv;
3921                 trans->bytes_reserved = num_bytes;
3922         }
3923         return trans;
3924 }
3925
3926 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
3927 {
3928         struct btrfs_root *root = BTRFS_I(dir)->root;
3929         struct btrfs_trans_handle *trans;
3930         struct inode *inode = dentry->d_inode;
3931         int ret;
3932
3933         trans = __unlink_start_trans(dir);
3934         if (IS_ERR(trans))
3935                 return PTR_ERR(trans);
3936
3937         btrfs_record_unlink_dir(trans, dir, dentry->d_inode, 0);
3938
3939         ret = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
3940                                  dentry->d_name.name, dentry->d_name.len);
3941         if (ret)
3942                 goto out;
3943
3944         if (inode->i_nlink == 0) {
3945                 ret = btrfs_orphan_add(trans, inode);
3946                 if (ret)
3947                         goto out;
3948         }
3949
3950 out:
3951         btrfs_end_transaction(trans, root);
3952         btrfs_btree_balance_dirty(root);
3953         return ret;
3954 }
3955
3956 int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
3957                         struct btrfs_root *root,
3958                         struct inode *dir, u64 objectid,
3959                         const char *name, int name_len)
3960 {
3961         struct btrfs_path *path;
3962         struct extent_buffer *leaf;
3963         struct btrfs_dir_item *di;
3964         struct btrfs_key key;
3965         u64 index;
3966         int ret;
3967         u64 dir_ino = btrfs_ino(dir);
3968
3969         path = btrfs_alloc_path();
3970         if (!path)
3971                 return -ENOMEM;
3972
3973         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3974                                    name, name_len, -1);
3975         if (IS_ERR_OR_NULL(di)) {
3976                 if (!di)
3977                         ret = -ENOENT;
3978                 else
3979                         ret = PTR_ERR(di);
3980                 goto out;
3981         }
3982
3983         leaf = path->nodes[0];
3984         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3985         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
3986         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3987         if (ret) {
3988                 btrfs_abort_transaction(trans, root, ret);
3989                 goto out;
3990         }
3991         btrfs_release_path(path);
3992
3993         ret = btrfs_del_root_ref(trans, root->fs_info->tree_root,
3994                                  objectid, root->root_key.objectid,
3995                                  dir_ino, &index, name, name_len);
3996         if (ret < 0) {
3997                 if (ret != -ENOENT) {
3998                         btrfs_abort_transaction(trans, root, ret);
3999                         goto out;
4000                 }
4001                 di = btrfs_search_dir_index_item(root, path, dir_ino,
4002                                                  name, name_len);
4003                 if (IS_ERR_OR_NULL(di)) {
4004                         if (!di)
4005                                 ret = -ENOENT;
4006                         else
4007                                 ret = PTR_ERR(di);
4008                         btrfs_abort_transaction(trans, root, ret);
4009                         goto out;
4010                 }
4011
4012                 leaf = path->nodes[0];
4013                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4014                 btrfs_release_path(path);
4015                 index = key.offset;
4016         }
4017         btrfs_release_path(path);
4018
4019         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
4020         if (ret) {
4021                 btrfs_abort_transaction(trans, root, ret);
4022                 goto out;
4023         }
4024
4025         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
4026         inode_inc_iversion(dir);
4027         dir->i_mtime = dir->i_ctime = CURRENT_TIME;
4028         ret = btrfs_update_inode_fallback(trans, root, dir);
4029         if (ret)
4030                 btrfs_abort_transaction(trans, root, ret);
4031 out:
4032         btrfs_free_path(path);
4033         return ret;
4034 }
4035
4036 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
4037 {
4038         struct inode *inode = dentry->d_inode;
4039         int err = 0;
4040         struct btrfs_root *root = BTRFS_I(dir)->root;
4041         struct btrfs_trans_handle *trans;
4042
4043         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE)
4044                 return -ENOTEMPTY;
4045         if (btrfs_ino(inode) == BTRFS_FIRST_FREE_OBJECTID)
4046                 return -EPERM;
4047
4048         trans = __unlink_start_trans(dir);
4049         if (IS_ERR(trans))
4050                 return PTR_ERR(trans);
4051
4052         if (unlikely(btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
4053                 err = btrfs_unlink_subvol(trans, root, dir,
4054                                           BTRFS_I(inode)->location.objectid,
4055                                           dentry->d_name.name,
4056                                           dentry->d_name.len);
4057                 goto out;
4058         }
4059
4060         err = btrfs_orphan_add(trans, inode);
4061         if (err)
4062                 goto out;
4063
4064         /* now the directory is empty */
4065         err = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
4066                                  dentry->d_name.name, dentry->d_name.len);
4067         if (!err)
4068                 btrfs_i_size_write(inode, 0);
4069 out:
4070         btrfs_end_transaction(trans, root);
4071         btrfs_btree_balance_dirty(root);
4072
4073         return err;
4074 }
4075
4076 /*
4077  * this can truncate away extent items, csum items and directory items.
4078  * It starts at a high offset and removes keys until it can't find
4079  * any higher than new_size
4080  *
4081  * csum items that cross the new i_size are truncated to the new size
4082  * as well.
4083  *
4084  * min_type is the minimum key type to truncate down to.  If set to 0, this
4085  * will kill all the items on this inode, including the INODE_ITEM_KEY.
4086  */
4087 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
4088                                struct btrfs_root *root,
4089                                struct inode *inode,
4090                                u64 new_size, u32 min_type)
4091 {
4092         struct btrfs_path *path;
4093         struct extent_buffer *leaf;
4094         struct btrfs_file_extent_item *fi;
4095         struct btrfs_key key;
4096         struct btrfs_key found_key;
4097         u64 extent_start = 0;
4098         u64 extent_num_bytes = 0;
4099         u64 extent_offset = 0;
4100         u64 item_end = 0;
4101         u64 last_size = (u64)-1;
4102         u32 found_type = (u8)-1;
4103         int found_extent;
4104         int del_item;
4105         int pending_del_nr = 0;
4106         int pending_del_slot = 0;
4107         int extent_type = -1;
4108         int ret;
4109         int err = 0;
4110         u64 ino = btrfs_ino(inode);
4111
4112         BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
4113
4114         path = btrfs_alloc_path();
4115         if (!path)
4116                 return -ENOMEM;
4117         path->reada = -1;
4118
4119         /*
4120          * We want to drop from the next block forward in case this new size is
4121          * not block aligned since we will be keeping the last block of the
4122          * extent just the way it is.
4123          */
4124         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4125             root == root->fs_info->tree_root)
4126                 btrfs_drop_extent_cache(inode, ALIGN(new_size,
4127                                         root->sectorsize), (u64)-1, 0);
4128
4129         /*
4130          * This function is also used to drop the items in the log tree before
4131          * we relog the inode, so if root != BTRFS_I(inode)->root, it means
4132          * it is used to drop the loged items. So we shouldn't kill the delayed
4133          * items.
4134          */
4135         if (min_type == 0 && root == BTRFS_I(inode)->root)
4136                 btrfs_kill_delayed_inode_items(inode);
4137
4138         key.objectid = ino;
4139         key.offset = (u64)-1;
4140         key.type = (u8)-1;
4141
4142 search_again:
4143         path->leave_spinning = 1;
4144         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
4145         if (ret < 0) {
4146                 err = ret;
4147                 goto out;
4148         }
4149
4150         if (ret > 0) {
4151                 /* there are no items in the tree for us to truncate, we're
4152                  * done
4153                  */
4154                 if (path->slots[0] == 0)
4155                         goto out;
4156                 path->slots[0]--;
4157         }
4158
4159         while (1) {
4160                 fi = NULL;
4161                 leaf = path->nodes[0];
4162                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4163                 found_type = found_key.type;
4164
4165                 if (found_key.objectid != ino)
4166                         break;
4167
4168                 if (found_type < min_type)
4169                         break;
4170
4171                 item_end = found_key.offset;
4172                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
4173                         fi = btrfs_item_ptr(leaf, path->slots[0],
4174                                             struct btrfs_file_extent_item);
4175                         extent_type = btrfs_file_extent_type(leaf, fi);
4176                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4177                                 item_end +=
4178                                     btrfs_file_extent_num_bytes(leaf, fi);
4179                         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4180                                 item_end += btrfs_file_extent_inline_len(leaf,
4181                                                          path->slots[0], fi);
4182                         }
4183                         item_end--;
4184                 }
4185                 if (found_type > min_type) {
4186                         del_item = 1;
4187                 } else {
4188                         if (item_end < new_size)
4189                                 break;
4190                         if (found_key.offset >= new_size)
4191                                 del_item = 1;
4192                         else
4193                                 del_item = 0;
4194                 }
4195                 found_extent = 0;
4196                 /* FIXME, shrink the extent if the ref count is only 1 */
4197                 if (found_type != BTRFS_EXTENT_DATA_KEY)
4198                         goto delete;
4199
4200                 if (del_item)
4201                         last_size = found_key.offset;
4202                 else
4203                         last_size = new_size;
4204
4205                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4206                         u64 num_dec;
4207                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
4208                         if (!del_item) {
4209                                 u64 orig_num_bytes =
4210                                         btrfs_file_extent_num_bytes(leaf, fi);
4211                                 extent_num_bytes = ALIGN(new_size -
4212                                                 found_key.offset,
4213                                                 root->sectorsize);
4214                                 btrfs_set_file_extent_num_bytes(leaf, fi,
4215                                                          extent_num_bytes);
4216                                 num_dec = (orig_num_bytes -
4217                                            extent_num_bytes);
4218                                 if (test_bit(BTRFS_ROOT_REF_COWS,
4219                                              &root->state) &&
4220                                     extent_start != 0)
4221                                         inode_sub_bytes(inode, num_dec);
4222                                 btrfs_mark_buffer_dirty(leaf);
4223                         } else {
4224                                 extent_num_bytes =
4225                                         btrfs_file_extent_disk_num_bytes(leaf,
4226                                                                          fi);
4227                                 extent_offset = found_key.offset -
4228                                         btrfs_file_extent_offset(leaf, fi);
4229
4230                                 /* FIXME blocksize != 4096 */
4231                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
4232                                 if (extent_start != 0) {
4233                                         found_extent = 1;
4234                                         if (test_bit(BTRFS_ROOT_REF_COWS,
4235                                                      &root->state))
4236                                                 inode_sub_bytes(inode, num_dec);
4237                                 }
4238                         }
4239                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4240                         /*
4241                          * we can't truncate inline items that have had
4242                          * special encodings
4243                          */
4244                         if (!del_item &&
4245                             btrfs_file_extent_compression(leaf, fi) == 0 &&
4246                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
4247                             btrfs_file_extent_other_encoding(leaf, fi) == 0) {
4248                                 u32 size = new_size - found_key.offset;
4249
4250                                 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state))
4251                                         inode_sub_bytes(inode, item_end + 1 -
4252                                                         new_size);
4253
4254                                 /*
4255                                  * update the ram bytes to properly reflect
4256                                  * the new size of our item
4257                                  */
4258                                 btrfs_set_file_extent_ram_bytes(leaf, fi, size);
4259                                 size =
4260                                     btrfs_file_extent_calc_inline_size(size);
4261                                 btrfs_truncate_item(root, path, size, 1);
4262                         } else if (test_bit(BTRFS_ROOT_REF_COWS,
4263                                             &root->state)) {
4264                                 inode_sub_bytes(inode, item_end + 1 -
4265                                                 found_key.offset);
4266                         }
4267                 }
4268 delete:
4269                 if (del_item) {
4270                         if (!pending_del_nr) {
4271                                 /* no pending yet, add ourselves */
4272                                 pending_del_slot = path->slots[0];
4273                                 pending_del_nr = 1;
4274                         } else if (pending_del_nr &&
4275                                    path->slots[0] + 1 == pending_del_slot) {
4276                                 /* hop on the pending chunk */
4277                                 pending_del_nr++;
4278                                 pending_del_slot = path->slots[0];
4279                         } else {
4280                                 BUG();
4281                         }
4282                 } else {
4283                         break;
4284                 }
4285                 if (found_extent &&
4286                     (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4287                      root == root->fs_info->tree_root)) {
4288                         btrfs_set_path_blocking(path);
4289                         ret = btrfs_free_extent(trans, root, extent_start,
4290                                                 extent_num_bytes, 0,
4291                                                 btrfs_header_owner(leaf),
4292                                                 ino, extent_offset, 0);
4293                         BUG_ON(ret);
4294                 }
4295
4296                 if (found_type == BTRFS_INODE_ITEM_KEY)
4297                         break;
4298
4299                 if (path->slots[0] == 0 ||
4300                     path->slots[0] != pending_del_slot) {
4301                         if (pending_del_nr) {
4302                                 ret = btrfs_del_items(trans, root, path,
4303                                                 pending_del_slot,
4304                                                 pending_del_nr);
4305                                 if (ret) {
4306                                         btrfs_abort_transaction(trans,
4307                                                                 root, ret);
4308                                         goto error;
4309                                 }
4310                                 pending_del_nr = 0;
4311                         }
4312                         btrfs_release_path(path);
4313                         goto search_again;
4314                 } else {
4315                         path->slots[0]--;
4316                 }
4317         }
4318 out:
4319         if (pending_del_nr) {
4320                 ret = btrfs_del_items(trans, root, path, pending_del_slot,
4321                                       pending_del_nr);
4322                 if (ret)
4323                         btrfs_abort_transaction(trans, root, ret);
4324         }
4325 error:
4326         if (last_size != (u64)-1 &&
4327             root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID)
4328                 btrfs_ordered_update_i_size(inode, last_size, NULL);
4329         btrfs_free_path(path);
4330         return err;
4331 }
4332
4333 /*
4334  * btrfs_truncate_page - read, zero a chunk and write a page
4335  * @inode - inode that we're zeroing
4336  * @from - the offset to start zeroing
4337  * @len - the length to zero, 0 to zero the entire range respective to the
4338  *      offset
4339  * @front - zero up to the offset instead of from the offset on
4340  *
4341  * This will find the page for the "from" offset and cow the page and zero the
4342  * part we want to zero.  This is used with truncate and hole punching.
4343  */
4344 int btrfs_truncate_page(struct inode *inode, loff_t from, loff_t len,
4345                         int front)
4346 {
4347         struct address_space *mapping = inode->i_mapping;
4348         struct btrfs_root *root = BTRFS_I(inode)->root;
4349         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4350         struct btrfs_ordered_extent *ordered;
4351         struct extent_state *cached_state = NULL;
4352         char *kaddr;
4353         u32 blocksize = root->sectorsize;
4354         pgoff_t index = from >> PAGE_CACHE_SHIFT;
4355         unsigned offset = from & (PAGE_CACHE_SIZE-1);
4356         struct page *page;
4357         gfp_t mask = btrfs_alloc_write_mask(mapping);
4358         int ret = 0;
4359         u64 page_start;
4360         u64 page_end;
4361
4362         if ((offset & (blocksize - 1)) == 0 &&
4363             (!len || ((len & (blocksize - 1)) == 0)))
4364                 goto out;
4365         ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
4366         if (ret)
4367                 goto out;
4368
4369 again:
4370         page = find_or_create_page(mapping, index, mask);
4371         if (!page) {
4372                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
4373                 ret = -ENOMEM;
4374                 goto out;
4375         }
4376
4377         page_start = page_offset(page);
4378         page_end = page_start + PAGE_CACHE_SIZE - 1;
4379
4380         if (!PageUptodate(page)) {
4381                 ret = btrfs_readpage(NULL, page);
4382                 lock_page(page);
4383                 if (page->mapping != mapping) {
4384                         unlock_page(page);
4385                         page_cache_release(page);
4386                         goto again;
4387                 }
4388                 if (!PageUptodate(page)) {
4389                         ret = -EIO;
4390                         goto out_unlock;
4391                 }
4392         }
4393         wait_on_page_writeback(page);
4394
4395         lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state);
4396         set_page_extent_mapped(page);
4397
4398         ordered = btrfs_lookup_ordered_extent(inode, page_start);
4399         if (ordered) {
4400                 unlock_extent_cached(io_tree, page_start, page_end,
4401                                      &cached_state, GFP_NOFS);
4402                 unlock_page(page);
4403                 page_cache_release(page);
4404                 btrfs_start_ordered_extent(inode, ordered, 1);
4405                 btrfs_put_ordered_extent(ordered);
4406                 goto again;
4407         }
4408
4409         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
4410                           EXTENT_DIRTY | EXTENT_DELALLOC |
4411                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
4412                           0, 0, &cached_state, GFP_NOFS);
4413
4414         ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
4415                                         &cached_state);
4416         if (ret) {
4417                 unlock_extent_cached(io_tree, page_start, page_end,
4418                                      &cached_state, GFP_NOFS);
4419                 goto out_unlock;
4420         }
4421
4422         if (offset != PAGE_CACHE_SIZE) {
4423                 if (!len)
4424                         len = PAGE_CACHE_SIZE - offset;
4425                 kaddr = kmap(page);
4426                 if (front)
4427                         memset(kaddr, 0, offset);
4428                 else
4429                         memset(kaddr + offset, 0, len);
4430                 flush_dcache_page(page);
4431                 kunmap(page);
4432         }
4433         ClearPageChecked(page);
4434         set_page_dirty(page);
4435         unlock_extent_cached(io_tree, page_start, page_end, &cached_state,
4436                              GFP_NOFS);
4437
4438 out_unlock:
4439         if (ret)
4440                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
4441         unlock_page(page);
4442         page_cache_release(page);
4443 out:
4444         return ret;
4445 }
4446
4447 static int maybe_insert_hole(struct btrfs_root *root, struct inode *inode,
4448                              u64 offset, u64 len)
4449 {
4450         struct btrfs_trans_handle *trans;
4451         int ret;
4452
4453         /*
4454          * Still need to make sure the inode looks like it's been updated so
4455          * that any holes get logged if we fsync.
4456          */
4457         if (btrfs_fs_incompat(root->fs_info, NO_HOLES)) {
4458                 BTRFS_I(inode)->last_trans = root->fs_info->generation;
4459                 BTRFS_I(inode)->last_sub_trans = root->log_transid;
4460                 BTRFS_I(inode)->last_log_commit = root->last_log_commit;
4461                 return 0;
4462         }
4463
4464         /*
4465          * 1 - for the one we're dropping
4466          * 1 - for the one we're adding
4467          * 1 - for updating the inode.
4468          */
4469         trans = btrfs_start_transaction(root, 3);
4470         if (IS_ERR(trans))
4471                 return PTR_ERR(trans);
4472
4473         ret = btrfs_drop_extents(trans, root, inode, offset, offset + len, 1);
4474         if (ret) {
4475                 btrfs_abort_transaction(trans, root, ret);
4476                 btrfs_end_transaction(trans, root);
4477                 return ret;
4478         }
4479
4480         ret = btrfs_insert_file_extent(trans, root, btrfs_ino(inode), offset,
4481                                        0, 0, len, 0, len, 0, 0, 0);
4482         if (ret)
4483                 btrfs_abort_transaction(trans, root, ret);
4484         else
4485                 btrfs_update_inode(trans, root, inode);
4486         btrfs_end_transaction(trans, root);
4487         return ret;
4488 }
4489
4490 /*
4491  * This function puts in dummy file extents for the area we're creating a hole
4492  * for.  So if we are truncating this file to a larger size we need to insert
4493  * these file extents so that btrfs_get_extent will return a EXTENT_MAP_HOLE for
4494  * the range between oldsize and size
4495  */
4496 int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size)
4497 {
4498         struct btrfs_root *root = BTRFS_I(inode)->root;
4499         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4500         struct extent_map *em = NULL;
4501         struct extent_state *cached_state = NULL;
4502         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
4503         u64 hole_start = ALIGN(oldsize, root->sectorsize);
4504         u64 block_end = ALIGN(size, root->sectorsize);
4505         u64 last_byte;
4506         u64 cur_offset;
4507         u64 hole_size;
4508         int err = 0;
4509
4510         /*
4511          * If our size started in the middle of a page we need to zero out the
4512          * rest of the page before we expand the i_size, otherwise we could
4513          * expose stale data.
4514          */
4515         err = btrfs_truncate_page(inode, oldsize, 0, 0);
4516         if (err)
4517                 return err;
4518
4519         if (size <= hole_start)
4520                 return 0;
4521
4522         while (1) {
4523                 struct btrfs_ordered_extent *ordered;
4524
4525                 lock_extent_bits(io_tree, hole_start, block_end - 1, 0,
4526                                  &cached_state);
4527                 ordered = btrfs_lookup_ordered_range(inode, hole_start,
4528                                                      block_end - hole_start);
4529                 if (!ordered)
4530                         break;
4531                 unlock_extent_cached(io_tree, hole_start, block_end - 1,
4532                                      &cached_state, GFP_NOFS);
4533                 btrfs_start_ordered_extent(inode, ordered, 1);
4534                 btrfs_put_ordered_extent(ordered);
4535         }
4536
4537         cur_offset = hole_start;
4538         while (1) {
4539                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
4540                                 block_end - cur_offset, 0);
4541                 if (IS_ERR(em)) {
4542                         err = PTR_ERR(em);
4543                         em = NULL;
4544                         break;
4545                 }
4546                 last_byte = min(extent_map_end(em), block_end);
4547                 last_byte = ALIGN(last_byte , root->sectorsize);
4548                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
4549                         struct extent_map *hole_em;
4550                         hole_size = last_byte - cur_offset;
4551
4552                         err = maybe_insert_hole(root, inode, cur_offset,
4553                                                 hole_size);
4554                         if (err)
4555                                 break;
4556                         btrfs_drop_extent_cache(inode, cur_offset,
4557                                                 cur_offset + hole_size - 1, 0);
4558                         hole_em = alloc_extent_map();
4559                         if (!hole_em) {
4560                                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
4561                                         &BTRFS_I(inode)->runtime_flags);
4562                                 goto next;
4563                         }
4564                         hole_em->start = cur_offset;
4565                         hole_em->len = hole_size;
4566                         hole_em->orig_start = cur_offset;
4567
4568                         hole_em->block_start = EXTENT_MAP_HOLE;
4569                         hole_em->block_len = 0;
4570                         hole_em->orig_block_len = 0;
4571                         hole_em->ram_bytes = hole_size;
4572                         hole_em->bdev = root->fs_info->fs_devices->latest_bdev;
4573                         hole_em->compress_type = BTRFS_COMPRESS_NONE;
4574                         hole_em->generation = root->fs_info->generation;
4575
4576                         while (1) {
4577                                 write_lock(&em_tree->lock);
4578                                 err = add_extent_mapping(em_tree, hole_em, 1);
4579                                 write_unlock(&em_tree->lock);
4580                                 if (err != -EEXIST)
4581                                         break;
4582                                 btrfs_drop_extent_cache(inode, cur_offset,
4583                                                         cur_offset +
4584                                                         hole_size - 1, 0);
4585                         }
4586                         free_extent_map(hole_em);
4587                 }
4588 next:
4589                 free_extent_map(em);
4590                 em = NULL;
4591                 cur_offset = last_byte;
4592                 if (cur_offset >= block_end)
4593                         break;
4594         }
4595         free_extent_map(em);
4596         unlock_extent_cached(io_tree, hole_start, block_end - 1, &cached_state,
4597                              GFP_NOFS);
4598         return err;
4599 }
4600
4601 static int btrfs_setsize(struct inode *inode, struct iattr *attr)
4602 {
4603         struct btrfs_root *root = BTRFS_I(inode)->root;
4604         struct btrfs_trans_handle *trans;
4605         loff_t oldsize = i_size_read(inode);
4606         loff_t newsize = attr->ia_size;
4607         int mask = attr->ia_valid;
4608         int ret;
4609
4610         /*
4611          * The regular truncate() case without ATTR_CTIME and ATTR_MTIME is a
4612          * special case where we need to update the times despite not having
4613          * these flags set.  For all other operations the VFS set these flags
4614          * explicitly if it wants a timestamp update.
4615          */
4616         if (newsize != oldsize) {
4617                 inode_inc_iversion(inode);
4618                 if (!(mask & (ATTR_CTIME | ATTR_MTIME)))
4619                         inode->i_ctime = inode->i_mtime =
4620                                 current_fs_time(inode->i_sb);
4621         }
4622
4623         if (newsize > oldsize) {
4624                 truncate_pagecache(inode, newsize);
4625                 ret = btrfs_cont_expand(inode, oldsize, newsize);
4626                 if (ret)
4627                         return ret;
4628
4629                 trans = btrfs_start_transaction(root, 1);
4630                 if (IS_ERR(trans))
4631                         return PTR_ERR(trans);
4632
4633                 i_size_write(inode, newsize);
4634                 btrfs_ordered_update_i_size(inode, i_size_read(inode), NULL);
4635                 ret = btrfs_update_inode(trans, root, inode);
4636                 btrfs_end_transaction(trans, root);
4637         } else {
4638
4639                 /*
4640                  * We're truncating a file that used to have good data down to
4641                  * zero. Make sure it gets into the ordered flush list so that
4642                  * any new writes get down to disk quickly.
4643                  */
4644                 if (newsize == 0)
4645                         set_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
4646                                 &BTRFS_I(inode)->runtime_flags);
4647
4648                 /*
4649                  * 1 for the orphan item we're going to add
4650                  * 1 for the orphan item deletion.
4651                  */
4652                 trans = btrfs_start_transaction(root, 2);
4653                 if (IS_ERR(trans))
4654                         return PTR_ERR(trans);
4655
4656                 /*
4657                  * We need to do this in case we fail at _any_ point during the
4658                  * actual truncate.  Once we do the truncate_setsize we could
4659                  * invalidate pages which forces any outstanding ordered io to
4660                  * be instantly completed which will give us extents that need
4661                  * to be truncated.  If we fail to get an orphan inode down we
4662                  * could have left over extents that were never meant to live,
4663                  * so we need to garuntee from this point on that everything
4664                  * will be consistent.
4665                  */
4666                 ret = btrfs_orphan_add(trans, inode);
4667                 btrfs_end_transaction(trans, root);
4668                 if (ret)
4669                         return ret;
4670
4671                 /* we don't support swapfiles, so vmtruncate shouldn't fail */
4672                 truncate_setsize(inode, newsize);
4673
4674                 /* Disable nonlocked read DIO to avoid the end less truncate */
4675                 btrfs_inode_block_unlocked_dio(inode);
4676                 inode_dio_wait(inode);
4677                 btrfs_inode_resume_unlocked_dio(inode);
4678
4679                 ret = btrfs_truncate(inode);
4680                 if (ret && inode->i_nlink) {
4681                         int err;
4682
4683                         /*
4684                          * failed to truncate, disk_i_size is only adjusted down
4685                          * as we remove extents, so it should represent the true
4686                          * size of the inode, so reset the in memory size and
4687                          * delete our orphan entry.
4688                          */
4689                         trans = btrfs_join_transaction(root);
4690                         if (IS_ERR(trans)) {
4691                                 btrfs_orphan_del(NULL, inode);
4692                                 return ret;
4693                         }
4694                         i_size_write(inode, BTRFS_I(inode)->disk_i_size);
4695                         err = btrfs_orphan_del(trans, inode);
4696                         if (err)
4697                                 btrfs_abort_transaction(trans, root, err);
4698                         btrfs_end_transaction(trans, root);
4699                 }
4700         }
4701
4702         return ret;
4703 }
4704
4705 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
4706 {
4707         struct inode *inode = dentry->d_inode;
4708         struct btrfs_root *root = BTRFS_I(inode)->root;
4709         int err;
4710
4711         if (btrfs_root_readonly(root))
4712                 return -EROFS;
4713
4714         err = inode_change_ok(inode, attr);
4715         if (err)
4716                 return err;
4717
4718         if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
4719                 err = btrfs_setsize(inode, attr);
4720                 if (err)
4721                         return err;
4722         }
4723
4724         if (attr->ia_valid) {
4725                 setattr_copy(inode, attr);
4726                 inode_inc_iversion(inode);
4727                 err = btrfs_dirty_inode(inode);
4728
4729                 if (!err && attr->ia_valid & ATTR_MODE)
4730                         err = posix_acl_chmod(inode, inode->i_mode);
4731         }
4732
4733         return err;
4734 }
4735
4736 /*
4737  * While truncating the inode pages during eviction, we get the VFS calling
4738  * btrfs_invalidatepage() against each page of the inode. This is slow because
4739  * the calls to btrfs_invalidatepage() result in a huge amount of calls to
4740  * lock_extent_bits() and clear_extent_bit(), which keep merging and splitting
4741  * extent_state structures over and over, wasting lots of time.
4742  *
4743  * Therefore if the inode is being evicted, let btrfs_invalidatepage() skip all
4744  * those expensive operations on a per page basis and do only the ordered io
4745  * finishing, while we release here the extent_map and extent_state structures,
4746  * without the excessive merging and splitting.
4747  */
4748 static void evict_inode_truncate_pages(struct inode *inode)
4749 {
4750         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4751         struct extent_map_tree *map_tree = &BTRFS_I(inode)->extent_tree;
4752         struct rb_node *node;
4753
4754         ASSERT(inode->i_state & I_FREEING);
4755         truncate_inode_pages_final(&inode->i_data);
4756
4757         write_lock(&map_tree->lock);
4758         while (!RB_EMPTY_ROOT(&map_tree->map)) {
4759                 struct extent_map *em;
4760
4761                 node = rb_first(&map_tree->map);
4762                 em = rb_entry(node, struct extent_map, rb_node);
4763                 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
4764                 clear_bit(EXTENT_FLAG_LOGGING, &em->flags);
4765                 remove_extent_mapping(map_tree, em);
4766                 free_extent_map(em);
4767                 if (need_resched()) {
4768                         write_unlock(&map_tree->lock);
4769                         cond_resched();
4770                         write_lock(&map_tree->lock);
4771                 }
4772         }
4773         write_unlock(&map_tree->lock);
4774
4775         spin_lock(&io_tree->lock);
4776         while (!RB_EMPTY_ROOT(&io_tree->state)) {
4777                 struct extent_state *state;
4778                 struct extent_state *cached_state = NULL;
4779
4780                 node = rb_first(&io_tree->state);
4781                 state = rb_entry(node, struct extent_state, rb_node);
4782                 atomic_inc(&state->refs);
4783                 spin_unlock(&io_tree->lock);
4784
4785                 lock_extent_bits(io_tree, state->start, state->end,
4786                                  0, &cached_state);
4787                 clear_extent_bit(io_tree, state->start, state->end,
4788                                  EXTENT_LOCKED | EXTENT_DIRTY |
4789                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
4790                                  EXTENT_DEFRAG, 1, 1,
4791                                  &cached_state, GFP_NOFS);
4792                 free_extent_state(state);
4793
4794                 cond_resched();
4795                 spin_lock(&io_tree->lock);
4796         }
4797         spin_unlock(&io_tree->lock);
4798 }
4799
4800 void btrfs_evict_inode(struct inode *inode)
4801 {
4802         struct btrfs_trans_handle *trans;
4803         struct btrfs_root *root = BTRFS_I(inode)->root;
4804         struct btrfs_block_rsv *rsv, *global_rsv;
4805         u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
4806         int ret;
4807
4808         trace_btrfs_inode_evict(inode);
4809
4810         evict_inode_truncate_pages(inode);
4811
4812         if (inode->i_nlink &&
4813             ((btrfs_root_refs(&root->root_item) != 0 &&
4814               root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID) ||
4815              btrfs_is_free_space_inode(inode)))
4816                 goto no_delete;
4817
4818         if (is_bad_inode(inode)) {
4819                 btrfs_orphan_del(NULL, inode);
4820                 goto no_delete;
4821         }
4822         /* do we really want it for ->i_nlink > 0 and zero btrfs_root_refs? */
4823         btrfs_wait_ordered_range(inode, 0, (u64)-1);
4824
4825         btrfs_free_io_failure_record(inode, 0, (u64)-1);
4826
4827         if (root->fs_info->log_root_recovering) {
4828                 BUG_ON(test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
4829                                  &BTRFS_I(inode)->runtime_flags));
4830                 goto no_delete;
4831         }
4832
4833         if (inode->i_nlink > 0) {
4834                 BUG_ON(btrfs_root_refs(&root->root_item) != 0 &&
4835                        root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID);
4836                 goto no_delete;
4837         }
4838
4839         ret = btrfs_commit_inode_delayed_inode(inode);
4840         if (ret) {
4841                 btrfs_orphan_del(NULL, inode);
4842                 goto no_delete;
4843         }
4844
4845         rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
4846         if (!rsv) {
4847                 btrfs_orphan_del(NULL, inode);
4848                 goto no_delete;
4849         }
4850         rsv->size = min_size;
4851         rsv->failfast = 1;
4852         global_rsv = &root->fs_info->global_block_rsv;
4853
4854         btrfs_i_size_write(inode, 0);
4855
4856         /*
4857          * This is a bit simpler than btrfs_truncate since we've already
4858          * reserved our space for our orphan item in the unlink, so we just
4859          * need to reserve some slack space in case we add bytes and update
4860          * inode item when doing the truncate.
4861          */
4862         while (1) {
4863                 ret = btrfs_block_rsv_refill(root, rsv, min_size,
4864                                              BTRFS_RESERVE_FLUSH_LIMIT);
4865
4866                 /*
4867                  * Try and steal from the global reserve since we will
4868                  * likely not use this space anyway, we want to try as
4869                  * hard as possible to get this to work.
4870                  */
4871                 if (ret)
4872                         ret = btrfs_block_rsv_migrate(global_rsv, rsv, min_size);
4873
4874                 if (ret) {
4875                         btrfs_warn(root->fs_info,
4876                                 "Could not get space for a delete, will truncate on mount %d",
4877                                 ret);
4878                         btrfs_orphan_del(NULL, inode);
4879                         btrfs_free_block_rsv(root, rsv);
4880                         goto no_delete;
4881                 }
4882
4883                 trans = btrfs_join_transaction(root);
4884                 if (IS_ERR(trans)) {
4885                         btrfs_orphan_del(NULL, inode);
4886                         btrfs_free_block_rsv(root, rsv);
4887                         goto no_delete;
4888                 }
4889
4890                 trans->block_rsv = rsv;
4891
4892                 ret = btrfs_truncate_inode_items(trans, root, inode, 0, 0);
4893                 if (ret != -ENOSPC)
4894                         break;
4895
4896                 trans->block_rsv = &root->fs_info->trans_block_rsv;
4897                 btrfs_end_transaction(trans, root);
4898                 trans = NULL;
4899                 btrfs_btree_balance_dirty(root);
4900         }
4901
4902         btrfs_free_block_rsv(root, rsv);
4903
4904         /*
4905          * Errors here aren't a big deal, it just means we leave orphan items
4906          * in the tree.  They will be cleaned up on the next mount.
4907          */
4908         if (ret == 0) {
4909                 trans->block_rsv = root->orphan_block_rsv;
4910                 btrfs_orphan_del(trans, inode);
4911         } else {
4912                 btrfs_orphan_del(NULL, inode);
4913         }
4914
4915         trans->block_rsv = &root->fs_info->trans_block_rsv;
4916         if (!(root == root->fs_info->tree_root ||
4917               root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID))
4918                 btrfs_return_ino(root, btrfs_ino(inode));
4919
4920         btrfs_end_transaction(trans, root);
4921         btrfs_btree_balance_dirty(root);
4922 no_delete:
4923         btrfs_remove_delayed_node(inode);
4924         clear_inode(inode);
4925         return;
4926 }
4927
4928 /*
4929  * this returns the key found in the dir entry in the location pointer.
4930  * If no dir entries were found, location->objectid is 0.
4931  */
4932 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
4933                                struct btrfs_key *location)
4934 {
4935         const char *name = dentry->d_name.name;
4936         int namelen = dentry->d_name.len;
4937         struct btrfs_dir_item *di;
4938         struct btrfs_path *path;
4939         struct btrfs_root *root = BTRFS_I(dir)->root;
4940         int ret = 0;
4941
4942         path = btrfs_alloc_path();
4943         if (!path)
4944                 return -ENOMEM;
4945
4946         di = btrfs_lookup_dir_item(NULL, root, path, btrfs_ino(dir), name,
4947                                     namelen, 0);
4948         if (IS_ERR(di))
4949                 ret = PTR_ERR(di);
4950
4951         if (IS_ERR_OR_NULL(di))
4952                 goto out_err;
4953
4954         btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
4955 out:
4956         btrfs_free_path(path);
4957         return ret;
4958 out_err:
4959         location->objectid = 0;
4960         goto out;
4961 }
4962
4963 /*
4964  * when we hit a tree root in a directory, the btrfs part of the inode
4965  * needs to be changed to reflect the root directory of the tree root.  This
4966  * is kind of like crossing a mount point.
4967  */
4968 static int fixup_tree_root_location(struct btrfs_root *root,
4969                                     struct inode *dir,
4970                                     struct dentry *dentry,
4971                                     struct btrfs_key *location,
4972                                     struct btrfs_root **sub_root)
4973 {
4974         struct btrfs_path *path;
4975         struct btrfs_root *new_root;
4976         struct btrfs_root_ref *ref;
4977         struct extent_buffer *leaf;
4978         int ret;
4979         int err = 0;
4980
4981         path = btrfs_alloc_path();
4982         if (!path) {
4983                 err = -ENOMEM;
4984                 goto out;
4985         }
4986
4987         err = -ENOENT;
4988         ret = btrfs_find_item(root->fs_info->tree_root, path,
4989                                 BTRFS_I(dir)->root->root_key.objectid,
4990                                 location->objectid, BTRFS_ROOT_REF_KEY, NULL);
4991         if (ret) {
4992                 if (ret < 0)
4993                         err = ret;
4994                 goto out;
4995         }
4996
4997         leaf = path->nodes[0];
4998         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
4999         if (btrfs_root_ref_dirid(leaf, ref) != btrfs_ino(dir) ||
5000             btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
5001                 goto out;
5002
5003         ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
5004                                    (unsigned long)(ref + 1),
5005                                    dentry->d_name.len);
5006         if (ret)
5007                 goto out;
5008
5009         btrfs_release_path(path);
5010
5011         new_root = btrfs_read_fs_root_no_name(root->fs_info, location);
5012         if (IS_ERR(new_root)) {
5013                 err = PTR_ERR(new_root);
5014                 goto out;
5015         }
5016
5017         *sub_root = new_root;
5018         location->objectid = btrfs_root_dirid(&new_root->root_item);
5019         location->type = BTRFS_INODE_ITEM_KEY;
5020         location->offset = 0;
5021         err = 0;
5022 out:
5023         btrfs_free_path(path);
5024         return err;
5025 }
5026
5027 static void inode_tree_add(struct inode *inode)
5028 {
5029         struct btrfs_root *root = BTRFS_I(inode)->root;
5030         struct btrfs_inode *entry;
5031         struct rb_node **p;
5032         struct rb_node *parent;
5033         struct rb_node *new = &BTRFS_I(inode)->rb_node;
5034         u64 ino = btrfs_ino(inode);
5035
5036         if (inode_unhashed(inode))
5037                 return;
5038         parent = NULL;
5039         spin_lock(&root->inode_lock);
5040         p = &root->inode_tree.rb_node;
5041         while (*p) {
5042                 parent = *p;
5043                 entry = rb_entry(parent, struct btrfs_inode, rb_node);
5044
5045                 if (ino < btrfs_ino(&entry->vfs_inode))
5046                         p = &parent->rb_left;
5047                 else if (ino > btrfs_ino(&entry->vfs_inode))
5048                         p = &parent->rb_right;
5049                 else {
5050                         WARN_ON(!(entry->vfs_inode.i_state &
5051                                   (I_WILL_FREE | I_FREEING)));
5052                         rb_replace_node(parent, new, &root->inode_tree);
5053                         RB_CLEAR_NODE(parent);
5054                         spin_unlock(&root->inode_lock);
5055                         return;
5056                 }
5057         }
5058         rb_link_node(new, parent, p);
5059         rb_insert_color(new, &root->inode_tree);
5060         spin_unlock(&root->inode_lock);
5061 }
5062
5063 static void inode_tree_del(struct inode *inode)
5064 {
5065         struct btrfs_root *root = BTRFS_I(inode)->root;
5066         int empty = 0;
5067
5068         spin_lock(&root->inode_lock);
5069         if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
5070                 rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
5071                 RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
5072                 empty = RB_EMPTY_ROOT(&root->inode_tree);
5073         }
5074         spin_unlock(&root->inode_lock);
5075
5076         if (empty && btrfs_root_refs(&root->root_item) == 0) {
5077                 synchronize_srcu(&root->fs_info->subvol_srcu);
5078                 spin_lock(&root->inode_lock);
5079                 empty = RB_EMPTY_ROOT(&root->inode_tree);
5080                 spin_unlock(&root->inode_lock);
5081                 if (empty)
5082                         btrfs_add_dead_root(root);
5083         }
5084 }
5085
5086 void btrfs_invalidate_inodes(struct btrfs_root *root)
5087 {
5088         struct rb_node *node;
5089         struct rb_node *prev;
5090         struct btrfs_inode *entry;
5091         struct inode *inode;
5092         u64 objectid = 0;
5093
5094         if (!test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
5095                 WARN_ON(btrfs_root_refs(&root->root_item) != 0);
5096
5097         spin_lock(&root->inode_lock);
5098 again:
5099         node = root->inode_tree.rb_node;
5100         prev = NULL;
5101         while (node) {
5102                 prev = node;
5103                 entry = rb_entry(node, struct btrfs_inode, rb_node);
5104
5105                 if (objectid < btrfs_ino(&entry->vfs_inode))
5106                         node = node->rb_left;
5107                 else if (objectid > btrfs_ino(&entry->vfs_inode))
5108                         node = node->rb_right;
5109                 else
5110                         break;
5111         }
5112         if (!node) {
5113                 while (prev) {
5114                         entry = rb_entry(prev, struct btrfs_inode, rb_node);
5115                         if (objectid <= btrfs_ino(&entry->vfs_inode)) {
5116                                 node = prev;
5117                                 break;
5118                         }
5119                         prev = rb_next(prev);
5120                 }
5121         }
5122         while (node) {
5123                 entry = rb_entry(node, struct btrfs_inode, rb_node);
5124                 objectid = btrfs_ino(&entry->vfs_inode) + 1;
5125                 inode = igrab(&entry->vfs_inode);
5126                 if (inode) {
5127                         spin_unlock(&root->inode_lock);
5128                         if (atomic_read(&inode->i_count) > 1)
5129                                 d_prune_aliases(inode);
5130                         /*
5131                          * btrfs_drop_inode will have it removed from
5132                          * the inode cache when its usage count
5133                          * hits zero.
5134                          */
5135                         iput(inode);
5136                         cond_resched();
5137                         spin_lock(&root->inode_lock);
5138                         goto again;
5139                 }
5140
5141                 if (cond_resched_lock(&root->inode_lock))
5142                         goto again;
5143
5144                 node = rb_next(node);
5145         }
5146         spin_unlock(&root->inode_lock);
5147 }
5148
5149 static int btrfs_init_locked_inode(struct inode *inode, void *p)
5150 {
5151         struct btrfs_iget_args *args = p;
5152         inode->i_ino = args->location->objectid;
5153         memcpy(&BTRFS_I(inode)->location, args->location,
5154                sizeof(*args->location));
5155         BTRFS_I(inode)->root = args->root;
5156         return 0;
5157 }
5158
5159 static int btrfs_find_actor(struct inode *inode, void *opaque)
5160 {
5161         struct btrfs_iget_args *args = opaque;
5162         return args->location->objectid == BTRFS_I(inode)->location.objectid &&
5163                 args->root == BTRFS_I(inode)->root;
5164 }
5165
5166 static struct inode *btrfs_iget_locked(struct super_block *s,
5167                                        struct btrfs_key *location,
5168                                        struct btrfs_root *root)
5169 {
5170         struct inode *inode;
5171         struct btrfs_iget_args args;
5172         unsigned long hashval = btrfs_inode_hash(location->objectid, root);
5173
5174         args.location = location;
5175         args.root = root;
5176
5177         inode = iget5_locked(s, hashval, btrfs_find_actor,
5178                              btrfs_init_locked_inode,
5179                              (void *)&args);
5180         return inode;
5181 }
5182
5183 /* Get an inode object given its location and corresponding root.
5184  * Returns in *is_new if the inode was read from disk
5185  */
5186 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
5187                          struct btrfs_root *root, int *new)
5188 {
5189         struct inode *inode;
5190
5191         inode = btrfs_iget_locked(s, location, root);
5192         if (!inode)
5193                 return ERR_PTR(-ENOMEM);
5194
5195         if (inode->i_state & I_NEW) {
5196                 btrfs_read_locked_inode(inode);
5197                 if (!is_bad_inode(inode)) {
5198                         inode_tree_add(inode);
5199                         unlock_new_inode(inode);
5200                         if (new)
5201                                 *new = 1;
5202                 } else {
5203                         unlock_new_inode(inode);
5204                         iput(inode);
5205                         inode = ERR_PTR(-ESTALE);
5206                 }
5207         }
5208
5209         return inode;
5210 }
5211
5212 static struct inode *new_simple_dir(struct super_block *s,
5213                                     struct btrfs_key *key,
5214                                     struct btrfs_root *root)
5215 {
5216         struct inode *inode = new_inode(s);
5217
5218         if (!inode)
5219                 return ERR_PTR(-ENOMEM);
5220
5221         BTRFS_I(inode)->root = root;
5222         memcpy(&BTRFS_I(inode)->location, key, sizeof(*key));
5223         set_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags);
5224
5225         inode->i_ino = BTRFS_EMPTY_SUBVOL_DIR_OBJECTID;
5226         inode->i_op = &btrfs_dir_ro_inode_operations;
5227         inode->i_fop = &simple_dir_operations;
5228         inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
5229         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
5230
5231         return inode;
5232 }
5233
5234 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
5235 {
5236         struct inode *inode;
5237         struct btrfs_root *root = BTRFS_I(dir)->root;
5238         struct btrfs_root *sub_root = root;
5239         struct btrfs_key location;
5240         int index;
5241         int ret = 0;
5242
5243         if (dentry->d_name.len > BTRFS_NAME_LEN)
5244                 return ERR_PTR(-ENAMETOOLONG);
5245
5246         ret = btrfs_inode_by_name(dir, dentry, &location);
5247         if (ret < 0)
5248                 return ERR_PTR(ret);
5249
5250         if (location.objectid == 0)
5251                 return ERR_PTR(-ENOENT);
5252
5253         if (location.type == BTRFS_INODE_ITEM_KEY) {
5254                 inode = btrfs_iget(dir->i_sb, &location, root, NULL);
5255                 return inode;
5256         }
5257
5258         BUG_ON(location.type != BTRFS_ROOT_ITEM_KEY);
5259
5260         index = srcu_read_lock(&root->fs_info->subvol_srcu);
5261         ret = fixup_tree_root_location(root, dir, dentry,
5262                                        &location, &sub_root);
5263         if (ret < 0) {
5264                 if (ret != -ENOENT)
5265                         inode = ERR_PTR(ret);
5266                 else
5267                         inode = new_simple_dir(dir->i_sb, &location, sub_root);
5268         } else {
5269                 inode = btrfs_iget(dir->i_sb, &location, sub_root, NULL);
5270         }
5271         srcu_read_unlock(&root->fs_info->subvol_srcu, index);
5272
5273         if (!IS_ERR(inode) && root != sub_root) {
5274                 down_read(&root->fs_info->cleanup_work_sem);
5275                 if (!(inode->i_sb->s_flags & MS_RDONLY))
5276                         ret = btrfs_orphan_cleanup(sub_root);
5277                 up_read(&root->fs_info->cleanup_work_sem);
5278                 if (ret) {
5279                         iput(inode);
5280                         inode = ERR_PTR(ret);
5281                 }
5282         }
5283
5284         return inode;
5285 }
5286
5287 static int btrfs_dentry_delete(const struct dentry *dentry)
5288 {
5289         struct btrfs_root *root;
5290         struct inode *inode = dentry->d_inode;
5291
5292         if (!inode && !IS_ROOT(dentry))
5293                 inode = dentry->d_parent->d_inode;
5294
5295         if (inode) {
5296                 root = BTRFS_I(inode)->root;
5297                 if (btrfs_root_refs(&root->root_item) == 0)
5298                         return 1;
5299
5300                 if (btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
5301                         return 1;
5302         }
5303         return 0;
5304 }
5305
5306 static void btrfs_dentry_release(struct dentry *dentry)
5307 {
5308         kfree(dentry->d_fsdata);
5309 }
5310
5311 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
5312                                    unsigned int flags)
5313 {
5314         struct inode *inode;
5315
5316         inode = btrfs_lookup_dentry(dir, dentry);
5317         if (IS_ERR(inode)) {
5318                 if (PTR_ERR(inode) == -ENOENT)
5319                         inode = NULL;
5320                 else
5321                         return ERR_CAST(inode);
5322         }
5323
5324         return d_materialise_unique(dentry, inode);
5325 }
5326
5327 unsigned char btrfs_filetype_table[] = {
5328         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
5329 };
5330
5331 static int btrfs_real_readdir(struct file *file, struct dir_context *ctx)
5332 {
5333         struct inode *inode = file_inode(file);
5334         struct btrfs_root *root = BTRFS_I(inode)->root;
5335         struct btrfs_item *item;
5336         struct btrfs_dir_item *di;
5337         struct btrfs_key key;
5338         struct btrfs_key found_key;
5339         struct btrfs_path *path;
5340         struct list_head ins_list;
5341         struct list_head del_list;
5342         int ret;
5343         struct extent_buffer *leaf;
5344         int slot;
5345         unsigned char d_type;
5346         int over = 0;
5347         u32 di_cur;
5348         u32 di_total;
5349         u32 di_len;
5350         int key_type = BTRFS_DIR_INDEX_KEY;
5351         char tmp_name[32];
5352         char *name_ptr;
5353         int name_len;
5354         int is_curr = 0;        /* ctx->pos points to the current index? */
5355
5356         /* FIXME, use a real flag for deciding about the key type */
5357         if (root->fs_info->tree_root == root)
5358                 key_type = BTRFS_DIR_ITEM_KEY;
5359
5360         if (!dir_emit_dots(file, ctx))
5361                 return 0;
5362
5363         path = btrfs_alloc_path();
5364         if (!path)
5365                 return -ENOMEM;
5366
5367         path->reada = 1;
5368
5369         if (key_type == BTRFS_DIR_INDEX_KEY) {
5370                 INIT_LIST_HEAD(&ins_list);
5371                 INIT_LIST_HEAD(&del_list);
5372                 btrfs_get_delayed_items(inode, &ins_list, &del_list);
5373         }
5374
5375         key.type = key_type;
5376         key.offset = ctx->pos;
5377         key.objectid = btrfs_ino(inode);
5378
5379         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5380         if (ret < 0)
5381                 goto err;
5382
5383         while (1) {
5384                 leaf = path->nodes[0];
5385                 slot = path->slots[0];
5386                 if (slot >= btrfs_header_nritems(leaf)) {
5387                         ret = btrfs_next_leaf(root, path);
5388                         if (ret < 0)
5389                                 goto err;
5390                         else if (ret > 0)
5391                                 break;
5392                         continue;
5393                 }
5394
5395                 item = btrfs_item_nr(slot);
5396                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
5397
5398                 if (found_key.objectid != key.objectid)
5399                         break;
5400                 if (found_key.type != key_type)
5401                         break;
5402                 if (found_key.offset < ctx->pos)
5403                         goto next;
5404                 if (key_type == BTRFS_DIR_INDEX_KEY &&
5405                     btrfs_should_delete_dir_index(&del_list,
5406                                                   found_key.offset))
5407                         goto next;
5408
5409                 ctx->pos = found_key.offset;
5410                 is_curr = 1;
5411
5412                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
5413                 di_cur = 0;
5414                 di_total = btrfs_item_size(leaf, item);
5415
5416                 while (di_cur < di_total) {
5417                         struct btrfs_key location;
5418
5419                         if (verify_dir_item(root, leaf, di))
5420                                 break;
5421
5422                         name_len = btrfs_dir_name_len(leaf, di);
5423                         if (name_len <= sizeof(tmp_name)) {
5424                                 name_ptr = tmp_name;
5425                         } else {
5426                                 name_ptr = kmalloc(name_len, GFP_NOFS);
5427                                 if (!name_ptr) {
5428                                         ret = -ENOMEM;
5429                                         goto err;
5430                                 }
5431                         }
5432                         read_extent_buffer(leaf, name_ptr,
5433                                            (unsigned long)(di + 1), name_len);
5434
5435                         d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)];
5436                         btrfs_dir_item_key_to_cpu(leaf, di, &location);
5437
5438
5439                         /* is this a reference to our own snapshot? If so
5440                          * skip it.
5441                          *
5442                          * In contrast to old kernels, we insert the snapshot's
5443                          * dir item and dir index after it has been created, so
5444                          * we won't find a reference to our own snapshot. We
5445                          * still keep the following code for backward
5446                          * compatibility.
5447                          */
5448                         if (location.type == BTRFS_ROOT_ITEM_KEY &&
5449                             location.objectid == root->root_key.objectid) {
5450                                 over = 0;
5451                                 goto skip;
5452                         }
5453                         over = !dir_emit(ctx, name_ptr, name_len,
5454                                        location.objectid, d_type);
5455
5456 skip:
5457                         if (name_ptr != tmp_name)
5458                                 kfree(name_ptr);
5459
5460                         if (over)
5461                                 goto nopos;
5462                         di_len = btrfs_dir_name_len(leaf, di) +
5463                                  btrfs_dir_data_len(leaf, di) + sizeof(*di);
5464                         di_cur += di_len;
5465                         di = (struct btrfs_dir_item *)((char *)di + di_len);
5466                 }
5467 next:
5468                 path->slots[0]++;
5469         }
5470
5471         if (key_type == BTRFS_DIR_INDEX_KEY) {
5472                 if (is_curr)
5473                         ctx->pos++;
5474                 ret = btrfs_readdir_delayed_dir_index(ctx, &ins_list);
5475                 if (ret)
5476                         goto nopos;
5477         }
5478
5479         /* Reached end of directory/root. Bump pos past the last item. */
5480         ctx->pos++;
5481
5482         /*
5483          * Stop new entries from being returned after we return the last
5484          * entry.
5485          *
5486          * New directory entries are assigned a strictly increasing
5487          * offset.  This means that new entries created during readdir
5488          * are *guaranteed* to be seen in the future by that readdir.
5489          * This has broken buggy programs which operate on names as
5490          * they're returned by readdir.  Until we re-use freed offsets
5491          * we have this hack to stop new entries from being returned
5492          * under the assumption that they'll never reach this huge
5493          * offset.
5494          *
5495          * This is being careful not to overflow 32bit loff_t unless the
5496          * last entry requires it because doing so has broken 32bit apps
5497          * in the past.
5498          */
5499         if (key_type == BTRFS_DIR_INDEX_KEY) {
5500                 if (ctx->pos >= INT_MAX)
5501                         ctx->pos = LLONG_MAX;
5502                 else
5503                         ctx->pos = INT_MAX;
5504         }
5505 nopos:
5506         ret = 0;
5507 err:
5508         if (key_type == BTRFS_DIR_INDEX_KEY)
5509                 btrfs_put_delayed_items(&ins_list, &del_list);
5510         btrfs_free_path(path);
5511         return ret;
5512 }
5513
5514 int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc)
5515 {
5516         struct btrfs_root *root = BTRFS_I(inode)->root;
5517         struct btrfs_trans_handle *trans;
5518         int ret = 0;
5519         bool nolock = false;
5520
5521         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5522                 return 0;
5523
5524         if (btrfs_fs_closing(root->fs_info) && btrfs_is_free_space_inode(inode))
5525                 nolock = true;
5526
5527         if (wbc->sync_mode == WB_SYNC_ALL) {
5528                 if (nolock)
5529                         trans = btrfs_join_transaction_nolock(root);
5530                 else
5531                         trans = btrfs_join_transaction(root);
5532                 if (IS_ERR(trans))
5533                         return PTR_ERR(trans);
5534                 ret = btrfs_commit_transaction(trans, root);
5535         }
5536         return ret;
5537 }
5538
5539 /*
5540  * This is somewhat expensive, updating the tree every time the
5541  * inode changes.  But, it is most likely to find the inode in cache.
5542  * FIXME, needs more benchmarking...there are no reasons other than performance
5543  * to keep or drop this code.
5544  */
5545 static int btrfs_dirty_inode(struct inode *inode)
5546 {
5547         struct btrfs_root *root = BTRFS_I(inode)->root;
5548         struct btrfs_trans_handle *trans;
5549         int ret;
5550
5551         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5552                 return 0;
5553
5554         trans = btrfs_join_transaction(root);
5555         if (IS_ERR(trans))
5556                 return PTR_ERR(trans);
5557
5558         ret = btrfs_update_inode(trans, root, inode);
5559         if (ret && ret == -ENOSPC) {
5560                 /* whoops, lets try again with the full transaction */
5561                 btrfs_end_transaction(trans, root);
5562                 trans = btrfs_start_transaction(root, 1);
5563                 if (IS_ERR(trans))
5564                         return PTR_ERR(trans);
5565
5566                 ret = btrfs_update_inode(trans, root, inode);
5567         }
5568         btrfs_end_transaction(trans, root);
5569         if (BTRFS_I(inode)->delayed_node)
5570                 btrfs_balance_delayed_items(root);
5571
5572         return ret;
5573 }
5574
5575 /*
5576  * This is a copy of file_update_time.  We need this so we can return error on
5577  * ENOSPC for updating the inode in the case of file write and mmap writes.
5578  */
5579 static int btrfs_update_time(struct inode *inode, struct timespec *now,
5580                              int flags)
5581 {
5582         struct btrfs_root *root = BTRFS_I(inode)->root;
5583
5584         if (btrfs_root_readonly(root))
5585                 return -EROFS;
5586
5587         if (flags & S_VERSION)
5588                 inode_inc_iversion(inode);
5589         if (flags & S_CTIME)
5590                 inode->i_ctime = *now;
5591         if (flags & S_MTIME)
5592                 inode->i_mtime = *now;
5593         if (flags & S_ATIME)
5594                 inode->i_atime = *now;
5595         return btrfs_dirty_inode(inode);
5596 }
5597
5598 /*
5599  * find the highest existing sequence number in a directory
5600  * and then set the in-memory index_cnt variable to reflect
5601  * free sequence numbers
5602  */
5603 static int btrfs_set_inode_index_count(struct inode *inode)
5604 {
5605         struct btrfs_root *root = BTRFS_I(inode)->root;
5606         struct btrfs_key key, found_key;
5607         struct btrfs_path *path;
5608         struct extent_buffer *leaf;
5609         int ret;
5610
5611         key.objectid = btrfs_ino(inode);
5612         key.type = BTRFS_DIR_INDEX_KEY;
5613         key.offset = (u64)-1;
5614
5615         path = btrfs_alloc_path();
5616         if (!path)
5617                 return -ENOMEM;
5618
5619         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5620         if (ret < 0)
5621                 goto out;
5622         /* FIXME: we should be able to handle this */
5623         if (ret == 0)
5624                 goto out;
5625         ret = 0;
5626
5627         /*
5628          * MAGIC NUMBER EXPLANATION:
5629          * since we search a directory based on f_pos we have to start at 2
5630          * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
5631          * else has to start at 2
5632          */
5633         if (path->slots[0] == 0) {
5634                 BTRFS_I(inode)->index_cnt = 2;
5635                 goto out;
5636         }
5637
5638         path->slots[0]--;
5639
5640         leaf = path->nodes[0];
5641         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5642
5643         if (found_key.objectid != btrfs_ino(inode) ||
5644             found_key.type != BTRFS_DIR_INDEX_KEY) {
5645                 BTRFS_I(inode)->index_cnt = 2;
5646                 goto out;
5647         }
5648
5649         BTRFS_I(inode)->index_cnt = found_key.offset + 1;
5650 out:
5651         btrfs_free_path(path);
5652         return ret;
5653 }
5654
5655 /*
5656  * helper to find a free sequence number in a given directory.  This current
5657  * code is very simple, later versions will do smarter things in the btree
5658  */
5659 int btrfs_set_inode_index(struct inode *dir, u64 *index)
5660 {
5661         int ret = 0;
5662
5663         if (BTRFS_I(dir)->index_cnt == (u64)-1) {
5664                 ret = btrfs_inode_delayed_dir_index_count(dir);
5665                 if (ret) {
5666                         ret = btrfs_set_inode_index_count(dir);
5667                         if (ret)
5668                                 return ret;
5669                 }
5670         }
5671
5672         *index = BTRFS_I(dir)->index_cnt;
5673         BTRFS_I(dir)->index_cnt++;
5674
5675         return ret;
5676 }
5677
5678 static int btrfs_insert_inode_locked(struct inode *inode)
5679 {
5680         struct btrfs_iget_args args;
5681         args.location = &BTRFS_I(inode)->location;
5682         args.root = BTRFS_I(inode)->root;
5683
5684         return insert_inode_locked4(inode,
5685                    btrfs_inode_hash(inode->i_ino, BTRFS_I(inode)->root),
5686                    btrfs_find_actor, &args);
5687 }
5688
5689 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
5690                                      struct btrfs_root *root,
5691                                      struct inode *dir,
5692                                      const char *name, int name_len,
5693                                      u64 ref_objectid, u64 objectid,
5694                                      umode_t mode, u64 *index)
5695 {
5696         struct inode *inode;
5697         struct btrfs_inode_item *inode_item;
5698         struct btrfs_key *location;
5699         struct btrfs_path *path;
5700         struct btrfs_inode_ref *ref;
5701         struct btrfs_key key[2];
5702         u32 sizes[2];
5703         int nitems = name ? 2 : 1;
5704         unsigned long ptr;
5705         int ret;
5706
5707         path = btrfs_alloc_path();
5708         if (!path)
5709                 return ERR_PTR(-ENOMEM);
5710
5711         inode = new_inode(root->fs_info->sb);
5712         if (!inode) {
5713                 btrfs_free_path(path);
5714                 return ERR_PTR(-ENOMEM);
5715         }
5716
5717         /*
5718          * O_TMPFILE, set link count to 0, so that after this point,
5719          * we fill in an inode item with the correct link count.
5720          */
5721         if (!name)
5722                 set_nlink(inode, 0);
5723
5724         /*
5725          * we have to initialize this early, so we can reclaim the inode
5726          * number if we fail afterwards in this function.
5727          */
5728         inode->i_ino = objectid;
5729
5730         if (dir && name) {
5731                 trace_btrfs_inode_request(dir);
5732
5733                 ret = btrfs_set_inode_index(dir, index);
5734                 if (ret) {
5735                         btrfs_free_path(path);
5736                         iput(inode);
5737                         return ERR_PTR(ret);
5738                 }
5739         } else if (dir) {
5740                 *index = 0;
5741         }
5742         /*
5743          * index_cnt is ignored for everything but a dir,
5744          * btrfs_get_inode_index_count has an explanation for the magic
5745          * number
5746          */
5747         BTRFS_I(inode)->index_cnt = 2;
5748         BTRFS_I(inode)->dir_index = *index;
5749         BTRFS_I(inode)->root = root;
5750         BTRFS_I(inode)->generation = trans->transid;
5751         inode->i_generation = BTRFS_I(inode)->generation;
5752
5753         /*
5754          * We could have gotten an inode number from somebody who was fsynced
5755          * and then removed in this same transaction, so let's just set full
5756          * sync since it will be a full sync anyway and this will blow away the
5757          * old info in the log.
5758          */
5759         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
5760
5761         key[0].objectid = objectid;
5762         key[0].type = BTRFS_INODE_ITEM_KEY;
5763         key[0].offset = 0;
5764
5765         sizes[0] = sizeof(struct btrfs_inode_item);
5766
5767         if (name) {
5768                 /*
5769                  * Start new inodes with an inode_ref. This is slightly more
5770                  * efficient for small numbers of hard links since they will
5771                  * be packed into one item. Extended refs will kick in if we
5772                  * add more hard links than can fit in the ref item.
5773                  */
5774                 key[1].objectid = objectid;
5775                 key[1].type = BTRFS_INODE_REF_KEY;
5776                 key[1].offset = ref_objectid;
5777
5778                 sizes[1] = name_len + sizeof(*ref);
5779         }
5780
5781         location = &BTRFS_I(inode)->location;
5782         location->objectid = objectid;
5783         location->offset = 0;
5784         location->type = BTRFS_INODE_ITEM_KEY;
5785
5786         ret = btrfs_insert_inode_locked(inode);
5787         if (ret < 0)
5788                 goto fail;
5789
5790         path->leave_spinning = 1;
5791         ret = btrfs_insert_empty_items(trans, root, path, key, sizes, nitems);
5792         if (ret != 0)
5793                 goto fail_unlock;
5794
5795         inode_init_owner(inode, dir, mode);
5796         inode_set_bytes(inode, 0);
5797         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
5798         inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
5799                                   struct btrfs_inode_item);
5800         memset_extent_buffer(path->nodes[0], 0, (unsigned long)inode_item,
5801                              sizeof(*inode_item));
5802         fill_inode_item(trans, path->nodes[0], inode_item, inode);
5803
5804         if (name) {
5805                 ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
5806                                      struct btrfs_inode_ref);
5807                 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
5808                 btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
5809                 ptr = (unsigned long)(ref + 1);
5810                 write_extent_buffer(path->nodes[0], name, ptr, name_len);
5811         }
5812
5813         btrfs_mark_buffer_dirty(path->nodes[0]);
5814         btrfs_free_path(path);
5815
5816         btrfs_inherit_iflags(inode, dir);
5817
5818         if (S_ISREG(mode)) {
5819                 if (btrfs_test_opt(root, NODATASUM))
5820                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
5821                 if (btrfs_test_opt(root, NODATACOW))
5822                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW |
5823                                 BTRFS_INODE_NODATASUM;
5824         }
5825
5826         inode_tree_add(inode);
5827
5828         trace_btrfs_inode_new(inode);
5829         btrfs_set_inode_last_trans(trans, inode);
5830
5831         btrfs_update_root_times(trans, root);
5832
5833         ret = btrfs_inode_inherit_props(trans, inode, dir);
5834         if (ret)
5835                 btrfs_err(root->fs_info,
5836                           "error inheriting props for ino %llu (root %llu): %d",
5837                           btrfs_ino(inode), root->root_key.objectid, ret);
5838
5839         return inode;
5840
5841 fail_unlock:
5842         unlock_new_inode(inode);
5843 fail:
5844         if (dir && name)
5845                 BTRFS_I(dir)->index_cnt--;
5846         btrfs_free_path(path);
5847         iput(inode);
5848         return ERR_PTR(ret);
5849 }
5850
5851 static inline u8 btrfs_inode_type(struct inode *inode)
5852 {
5853         return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
5854 }
5855
5856 /*
5857  * utility function to add 'inode' into 'parent_inode' with
5858  * a give name and a given sequence number.
5859  * if 'add_backref' is true, also insert a backref from the
5860  * inode to the parent directory.
5861  */
5862 int btrfs_add_link(struct btrfs_trans_handle *trans,
5863                    struct inode *parent_inode, struct inode *inode,
5864                    const char *name, int name_len, int add_backref, u64 index)
5865 {
5866         int ret = 0;
5867         struct btrfs_key key;
5868         struct btrfs_root *root = BTRFS_I(parent_inode)->root;
5869         u64 ino = btrfs_ino(inode);
5870         u64 parent_ino = btrfs_ino(parent_inode);
5871
5872         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
5873                 memcpy(&key, &BTRFS_I(inode)->root->root_key, sizeof(key));
5874         } else {
5875                 key.objectid = ino;
5876                 key.type = BTRFS_INODE_ITEM_KEY;
5877                 key.offset = 0;
5878         }
5879
5880         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
5881                 ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
5882                                          key.objectid, root->root_key.objectid,
5883                                          parent_ino, index, name, name_len);
5884         } else if (add_backref) {
5885                 ret = btrfs_insert_inode_ref(trans, root, name, name_len, ino,
5886                                              parent_ino, index);
5887         }
5888
5889         /* Nothing to clean up yet */
5890         if (ret)
5891                 return ret;
5892
5893         ret = btrfs_insert_dir_item(trans, root, name, name_len,
5894                                     parent_inode, &key,
5895                                     btrfs_inode_type(inode), index);
5896         if (ret == -EEXIST || ret == -EOVERFLOW)
5897                 goto fail_dir_item;
5898         else if (ret) {
5899                 btrfs_abort_transaction(trans, root, ret);
5900                 return ret;
5901         }
5902
5903         btrfs_i_size_write(parent_inode, parent_inode->i_size +
5904                            name_len * 2);
5905         inode_inc_iversion(parent_inode);
5906         parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
5907         ret = btrfs_update_inode(trans, root, parent_inode);
5908         if (ret)
5909                 btrfs_abort_transaction(trans, root, ret);
5910         return ret;
5911
5912 fail_dir_item:
5913         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
5914                 u64 local_index;
5915                 int err;
5916                 err = btrfs_del_root_ref(trans, root->fs_info->tree_root,
5917                                  key.objectid, root->root_key.objectid,
5918                                  parent_ino, &local_index, name, name_len);
5919
5920         } else if (add_backref) {
5921                 u64 local_index;
5922                 int err;
5923
5924                 err = btrfs_del_inode_ref(trans, root, name, name_len,
5925                                           ino, parent_ino, &local_index);
5926         }
5927         return ret;
5928 }
5929
5930 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
5931                             struct inode *dir, struct dentry *dentry,
5932                             struct inode *inode, int backref, u64 index)
5933 {
5934         int err = btrfs_add_link(trans, dir, inode,
5935                                  dentry->d_name.name, dentry->d_name.len,
5936                                  backref, index);
5937         if (err > 0)
5938                 err = -EEXIST;
5939         return err;
5940 }
5941
5942 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
5943                         umode_t mode, dev_t rdev)
5944 {
5945         struct btrfs_trans_handle *trans;
5946         struct btrfs_root *root = BTRFS_I(dir)->root;
5947         struct inode *inode = NULL;
5948         int err;
5949         int drop_inode = 0;
5950         u64 objectid;
5951         u64 index = 0;
5952
5953         if (!new_valid_dev(rdev))
5954                 return -EINVAL;
5955
5956         /*
5957          * 2 for inode item and ref
5958          * 2 for dir items
5959          * 1 for xattr if selinux is on
5960          */
5961         trans = btrfs_start_transaction(root, 5);
5962         if (IS_ERR(trans))
5963                 return PTR_ERR(trans);
5964
5965         err = btrfs_find_free_ino(root, &objectid);
5966         if (err)
5967                 goto out_unlock;
5968
5969         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
5970                                 dentry->d_name.len, btrfs_ino(dir), objectid,
5971                                 mode, &index);
5972         if (IS_ERR(inode)) {
5973                 err = PTR_ERR(inode);
5974                 goto out_unlock;
5975         }
5976
5977         /*
5978         * If the active LSM wants to access the inode during
5979         * d_instantiate it needs these. Smack checks to see
5980         * if the filesystem supports xattrs by looking at the
5981         * ops vector.
5982         */
5983         inode->i_op = &btrfs_special_inode_operations;
5984         init_special_inode(inode, inode->i_mode, rdev);
5985
5986         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
5987         if (err)
5988                 goto out_unlock_inode;
5989
5990         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
5991         if (err) {
5992                 goto out_unlock_inode;
5993         } else {
5994                 btrfs_update_inode(trans, root, inode);
5995                 unlock_new_inode(inode);
5996                 d_instantiate(dentry, inode);
5997         }
5998
5999 out_unlock:
6000         btrfs_end_transaction(trans, root);
6001         btrfs_balance_delayed_items(root);
6002         btrfs_btree_balance_dirty(root);
6003         if (drop_inode) {
6004                 inode_dec_link_count(inode);
6005                 iput(inode);
6006         }
6007         return err;
6008
6009 out_unlock_inode:
6010         drop_inode = 1;
6011         unlock_new_inode(inode);
6012         goto out_unlock;
6013
6014 }
6015
6016 static int btrfs_create(struct inode *dir, struct dentry *dentry,
6017                         umode_t mode, bool excl)
6018 {
6019         struct btrfs_trans_handle *trans;
6020         struct btrfs_root *root = BTRFS_I(dir)->root;
6021         struct inode *inode = NULL;
6022         int drop_inode_on_err = 0;
6023         int err;
6024         u64 objectid;
6025         u64 index = 0;
6026
6027         /*
6028          * 2 for inode item and ref
6029          * 2 for dir items
6030          * 1 for xattr if selinux is on
6031          */
6032         trans = btrfs_start_transaction(root, 5);
6033         if (IS_ERR(trans))
6034                 return PTR_ERR(trans);
6035
6036         err = btrfs_find_free_ino(root, &objectid);
6037         if (err)
6038                 goto out_unlock;
6039
6040         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6041                                 dentry->d_name.len, btrfs_ino(dir), objectid,
6042                                 mode, &index);
6043         if (IS_ERR(inode)) {
6044                 err = PTR_ERR(inode);
6045                 goto out_unlock;
6046         }
6047         drop_inode_on_err = 1;
6048         /*
6049         * If the active LSM wants to access the inode during
6050         * d_instantiate it needs these. Smack checks to see
6051         * if the filesystem supports xattrs by looking at the
6052         * ops vector.
6053         */
6054         inode->i_fop = &btrfs_file_operations;
6055         inode->i_op = &btrfs_file_inode_operations;
6056         inode->i_mapping->a_ops = &btrfs_aops;
6057         inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
6058
6059         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6060         if (err)
6061                 goto out_unlock_inode;
6062
6063         err = btrfs_update_inode(trans, root, inode);
6064         if (err)
6065                 goto out_unlock_inode;
6066
6067         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
6068         if (err)
6069                 goto out_unlock_inode;
6070
6071         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
6072         unlock_new_inode(inode);
6073         d_instantiate(dentry, inode);
6074
6075 out_unlock:
6076         btrfs_end_transaction(trans, root);
6077         if (err && drop_inode_on_err) {
6078                 inode_dec_link_count(inode);
6079                 iput(inode);
6080         }
6081         btrfs_balance_delayed_items(root);
6082         btrfs_btree_balance_dirty(root);
6083         return err;
6084
6085 out_unlock_inode:
6086         unlock_new_inode(inode);
6087         goto out_unlock;
6088
6089 }
6090
6091 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
6092                       struct dentry *dentry)
6093 {
6094         struct btrfs_trans_handle *trans;
6095         struct btrfs_root *root = BTRFS_I(dir)->root;
6096         struct inode *inode = old_dentry->d_inode;
6097         u64 index;
6098         int err;
6099         int drop_inode = 0;
6100
6101         /* do not allow sys_link's with other subvols of the same device */
6102         if (root->objectid != BTRFS_I(inode)->root->objectid)
6103                 return -EXDEV;
6104
6105         if (inode->i_nlink >= BTRFS_LINK_MAX)
6106                 return -EMLINK;
6107
6108         err = btrfs_set_inode_index(dir, &index);
6109         if (err)
6110                 goto fail;
6111
6112         /*
6113          * 2 items for inode and inode ref
6114          * 2 items for dir items
6115          * 1 item for parent inode
6116          */
6117         trans = btrfs_start_transaction(root, 5);
6118         if (IS_ERR(trans)) {
6119                 err = PTR_ERR(trans);
6120                 goto fail;
6121         }
6122
6123         /* There are several dir indexes for this inode, clear the cache. */
6124         BTRFS_I(inode)->dir_index = 0ULL;
6125         inc_nlink(inode);
6126         inode_inc_iversion(inode);
6127         inode->i_ctime = CURRENT_TIME;
6128         ihold(inode);
6129         set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
6130
6131         err = btrfs_add_nondir(trans, dir, dentry, inode, 1, index);
6132
6133         if (err) {
6134                 drop_inode = 1;
6135         } else {
6136                 struct dentry *parent = dentry->d_parent;
6137                 err = btrfs_update_inode(trans, root, inode);
6138                 if (err)
6139                         goto fail;
6140                 if (inode->i_nlink == 1) {
6141                         /*
6142                          * If new hard link count is 1, it's a file created
6143                          * with open(2) O_TMPFILE flag.
6144                          */
6145                         err = btrfs_orphan_del(trans, inode);
6146                         if (err)
6147                                 goto fail;
6148                 }
6149                 d_instantiate(dentry, inode);
6150                 btrfs_log_new_name(trans, inode, NULL, parent);
6151         }
6152
6153         btrfs_end_transaction(trans, root);
6154         btrfs_balance_delayed_items(root);
6155 fail:
6156         if (drop_inode) {
6157                 inode_dec_link_count(inode);
6158                 iput(inode);
6159         }
6160         btrfs_btree_balance_dirty(root);
6161         return err;
6162 }
6163
6164 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
6165 {
6166         struct inode *inode = NULL;
6167         struct btrfs_trans_handle *trans;
6168         struct btrfs_root *root = BTRFS_I(dir)->root;
6169         int err = 0;
6170         int drop_on_err = 0;
6171         u64 objectid = 0;
6172         u64 index = 0;
6173
6174         /*
6175          * 2 items for inode and ref
6176          * 2 items for dir items
6177          * 1 for xattr if selinux is on
6178          */
6179         trans = btrfs_start_transaction(root, 5);
6180         if (IS_ERR(trans))
6181                 return PTR_ERR(trans);
6182
6183         err = btrfs_find_free_ino(root, &objectid);
6184         if (err)
6185                 goto out_fail;
6186
6187         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6188                                 dentry->d_name.len, btrfs_ino(dir), objectid,
6189                                 S_IFDIR | mode, &index);
6190         if (IS_ERR(inode)) {
6191                 err = PTR_ERR(inode);
6192                 goto out_fail;
6193         }
6194
6195         drop_on_err = 1;
6196         /* these must be set before we unlock the inode */
6197         inode->i_op = &btrfs_dir_inode_operations;
6198         inode->i_fop = &btrfs_dir_file_operations;
6199
6200         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6201         if (err)
6202                 goto out_fail_inode;
6203
6204         btrfs_i_size_write(inode, 0);
6205         err = btrfs_update_inode(trans, root, inode);
6206         if (err)
6207                 goto out_fail_inode;
6208
6209         err = btrfs_add_link(trans, dir, inode, dentry->d_name.name,
6210                              dentry->d_name.len, 0, index);
6211         if (err)
6212                 goto out_fail_inode;
6213
6214         d_instantiate(dentry, inode);
6215         /*
6216          * mkdir is special.  We're unlocking after we call d_instantiate
6217          * to avoid a race with nfsd calling d_instantiate.
6218          */
6219         unlock_new_inode(inode);
6220         drop_on_err = 0;
6221
6222 out_fail:
6223         btrfs_end_transaction(trans, root);
6224         if (drop_on_err)
6225                 iput(inode);
6226         btrfs_balance_delayed_items(root);
6227         btrfs_btree_balance_dirty(root);
6228         return err;
6229
6230 out_fail_inode:
6231         unlock_new_inode(inode);
6232         goto out_fail;
6233 }
6234
6235 /* Find next extent map of a given extent map, caller needs to ensure locks */
6236 static struct extent_map *next_extent_map(struct extent_map *em)
6237 {
6238         struct rb_node *next;
6239
6240         next = rb_next(&em->rb_node);
6241         if (!next)
6242                 return NULL;
6243         return container_of(next, struct extent_map, rb_node);
6244 }
6245
6246 static struct extent_map *prev_extent_map(struct extent_map *em)
6247 {
6248         struct rb_node *prev;
6249
6250         prev = rb_prev(&em->rb_node);
6251         if (!prev)
6252                 return NULL;
6253         return container_of(prev, struct extent_map, rb_node);
6254 }
6255
6256 /* helper for btfs_get_extent.  Given an existing extent in the tree,
6257  * the existing extent is the nearest extent to map_start,
6258  * and an extent that you want to insert, deal with overlap and insert
6259  * the best fitted new extent into the tree.
6260  */
6261 static int merge_extent_mapping(struct extent_map_tree *em_tree,
6262                                 struct extent_map *existing,
6263                                 struct extent_map *em,
6264                                 u64 map_start)
6265 {
6266         struct extent_map *prev;
6267         struct extent_map *next;
6268         u64 start;
6269         u64 end;
6270         u64 start_diff;
6271
6272         BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
6273
6274         if (existing->start > map_start) {
6275                 next = existing;
6276                 prev = prev_extent_map(next);
6277         } else {
6278                 prev = existing;
6279                 next = next_extent_map(prev);
6280         }
6281
6282         start = prev ? extent_map_end(prev) : em->start;
6283         start = max_t(u64, start, em->start);
6284         end = next ? next->start : extent_map_end(em);
6285         end = min_t(u64, end, extent_map_end(em));
6286         start_diff = start - em->start;
6287         em->start = start;
6288         em->len = end - start;
6289         if (em->block_start < EXTENT_MAP_LAST_BYTE &&
6290             !test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
6291                 em->block_start += start_diff;
6292                 em->block_len -= start_diff;
6293         }
6294         return add_extent_mapping(em_tree, em, 0);
6295 }
6296
6297 static noinline int uncompress_inline(struct btrfs_path *path,
6298                                       struct inode *inode, struct page *page,
6299                                       size_t pg_offset, u64 extent_offset,
6300                                       struct btrfs_file_extent_item *item)
6301 {
6302         int ret;
6303         struct extent_buffer *leaf = path->nodes[0];
6304         char *tmp;
6305         size_t max_size;
6306         unsigned long inline_size;
6307         unsigned long ptr;
6308         int compress_type;
6309
6310         WARN_ON(pg_offset != 0);
6311         compress_type = btrfs_file_extent_compression(leaf, item);
6312         max_size = btrfs_file_extent_ram_bytes(leaf, item);
6313         inline_size = btrfs_file_extent_inline_item_len(leaf,
6314                                         btrfs_item_nr(path->slots[0]));
6315         tmp = kmalloc(inline_size, GFP_NOFS);
6316         if (!tmp)
6317                 return -ENOMEM;
6318         ptr = btrfs_file_extent_inline_start(item);
6319
6320         read_extent_buffer(leaf, tmp, ptr, inline_size);
6321
6322         max_size = min_t(unsigned long, PAGE_CACHE_SIZE, max_size);
6323         ret = btrfs_decompress(compress_type, tmp, page,
6324                                extent_offset, inline_size, max_size);
6325         kfree(tmp);
6326         return ret;
6327 }
6328
6329 /*
6330  * a bit scary, this does extent mapping from logical file offset to the disk.
6331  * the ugly parts come from merging extents from the disk with the in-ram
6332  * representation.  This gets more complex because of the data=ordered code,
6333  * where the in-ram extents might be locked pending data=ordered completion.
6334  *
6335  * This also copies inline extents directly into the page.
6336  */
6337
6338 struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
6339                                     size_t pg_offset, u64 start, u64 len,
6340                                     int create)
6341 {
6342         int ret;
6343         int err = 0;
6344         u64 extent_start = 0;
6345         u64 extent_end = 0;
6346         u64 objectid = btrfs_ino(inode);
6347         u32 found_type;
6348         struct btrfs_path *path = NULL;
6349         struct btrfs_root *root = BTRFS_I(inode)->root;
6350         struct btrfs_file_extent_item *item;
6351         struct extent_buffer *leaf;
6352         struct btrfs_key found_key;
6353         struct extent_map *em = NULL;
6354         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
6355         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
6356         struct btrfs_trans_handle *trans = NULL;
6357         const bool new_inline = !page || create;
6358
6359 again:
6360         read_lock(&em_tree->lock);
6361         em = lookup_extent_mapping(em_tree, start, len);
6362         if (em)
6363                 em->bdev = root->fs_info->fs_devices->latest_bdev;
6364         read_unlock(&em_tree->lock);
6365
6366         if (em) {
6367                 if (em->start > start || em->start + em->len <= start)
6368                         free_extent_map(em);
6369                 else if (em->block_start == EXTENT_MAP_INLINE && page)
6370                         free_extent_map(em);
6371                 else
6372                         goto out;
6373         }
6374         em = alloc_extent_map();
6375         if (!em) {
6376                 err = -ENOMEM;
6377                 goto out;
6378         }
6379         em->bdev = root->fs_info->fs_devices->latest_bdev;
6380         em->start = EXTENT_MAP_HOLE;
6381         em->orig_start = EXTENT_MAP_HOLE;
6382         em->len = (u64)-1;
6383         em->block_len = (u64)-1;
6384
6385         if (!path) {
6386                 path = btrfs_alloc_path();
6387                 if (!path) {
6388                         err = -ENOMEM;
6389                         goto out;
6390                 }
6391                 /*
6392                  * Chances are we'll be called again, so go ahead and do
6393                  * readahead
6394                  */
6395                 path->reada = 1;
6396         }
6397
6398         ret = btrfs_lookup_file_extent(trans, root, path,
6399                                        objectid, start, trans != NULL);
6400         if (ret < 0) {
6401                 err = ret;
6402                 goto out;
6403         }
6404
6405         if (ret != 0) {
6406                 if (path->slots[0] == 0)
6407                         goto not_found;
6408                 path->slots[0]--;
6409         }
6410
6411         leaf = path->nodes[0];
6412         item = btrfs_item_ptr(leaf, path->slots[0],
6413                               struct btrfs_file_extent_item);
6414         /* are we inside the extent that was found? */
6415         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6416         found_type = found_key.type;
6417         if (found_key.objectid != objectid ||
6418             found_type != BTRFS_EXTENT_DATA_KEY) {
6419                 /*
6420                  * If we backup past the first extent we want to move forward
6421                  * and see if there is an extent in front of us, otherwise we'll
6422                  * say there is a hole for our whole search range which can
6423                  * cause problems.
6424                  */
6425                 extent_end = start;
6426                 goto next;
6427         }
6428
6429         found_type = btrfs_file_extent_type(leaf, item);
6430         extent_start = found_key.offset;
6431         if (found_type == BTRFS_FILE_EXTENT_REG ||
6432             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6433                 extent_end = extent_start +
6434                        btrfs_file_extent_num_bytes(leaf, item);
6435         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6436                 size_t size;
6437                 size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
6438                 extent_end = ALIGN(extent_start + size, root->sectorsize);
6439         }
6440 next:
6441         if (start >= extent_end) {
6442                 path->slots[0]++;
6443                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
6444                         ret = btrfs_next_leaf(root, path);
6445                         if (ret < 0) {
6446                                 err = ret;
6447                                 goto out;
6448                         }
6449                         if (ret > 0)
6450                                 goto not_found;
6451                         leaf = path->nodes[0];
6452                 }
6453                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6454                 if (found_key.objectid != objectid ||
6455                     found_key.type != BTRFS_EXTENT_DATA_KEY)
6456                         goto not_found;
6457                 if (start + len <= found_key.offset)
6458                         goto not_found;
6459                 if (start > found_key.offset)
6460                         goto next;
6461                 em->start = start;
6462                 em->orig_start = start;
6463                 em->len = found_key.offset - start;
6464                 goto not_found_em;
6465         }
6466
6467         btrfs_extent_item_to_extent_map(inode, path, item, new_inline, em);
6468
6469         if (found_type == BTRFS_FILE_EXTENT_REG ||
6470             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6471                 goto insert;
6472         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6473                 unsigned long ptr;
6474                 char *map;
6475                 size_t size;
6476                 size_t extent_offset;
6477                 size_t copy_size;
6478
6479                 if (new_inline)
6480                         goto out;
6481
6482                 size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
6483                 extent_offset = page_offset(page) + pg_offset - extent_start;
6484                 copy_size = min_t(u64, PAGE_CACHE_SIZE - pg_offset,
6485                                 size - extent_offset);
6486                 em->start = extent_start + extent_offset;
6487                 em->len = ALIGN(copy_size, root->sectorsize);
6488                 em->orig_block_len = em->len;
6489                 em->orig_start = em->start;
6490                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
6491                 if (create == 0 && !PageUptodate(page)) {
6492                         if (btrfs_file_extent_compression(leaf, item) !=
6493                             BTRFS_COMPRESS_NONE) {
6494                                 ret = uncompress_inline(path, inode, page,
6495                                                         pg_offset,
6496                                                         extent_offset, item);
6497                                 if (ret) {
6498                                         err = ret;
6499                                         goto out;
6500                                 }
6501                         } else {
6502                                 map = kmap(page);
6503                                 read_extent_buffer(leaf, map + pg_offset, ptr,
6504                                                    copy_size);
6505                                 if (pg_offset + copy_size < PAGE_CACHE_SIZE) {
6506                                         memset(map + pg_offset + copy_size, 0,
6507                                                PAGE_CACHE_SIZE - pg_offset -
6508                                                copy_size);
6509                                 }
6510                                 kunmap(page);
6511                         }
6512                         flush_dcache_page(page);
6513                 } else if (create && PageUptodate(page)) {
6514                         BUG();
6515                         if (!trans) {
6516                                 kunmap(page);
6517                                 free_extent_map(em);
6518                                 em = NULL;
6519
6520                                 btrfs_release_path(path);
6521                                 trans = btrfs_join_transaction(root);
6522
6523                                 if (IS_ERR(trans))
6524                                         return ERR_CAST(trans);
6525                                 goto again;
6526                         }
6527                         map = kmap(page);
6528                         write_extent_buffer(leaf, map + pg_offset, ptr,
6529                                             copy_size);
6530                         kunmap(page);
6531                         btrfs_mark_buffer_dirty(leaf);
6532                 }
6533                 set_extent_uptodate(io_tree, em->start,
6534                                     extent_map_end(em) - 1, NULL, GFP_NOFS);
6535                 goto insert;
6536         }
6537 not_found:
6538         em->start = start;
6539         em->orig_start = start;
6540         em->len = len;
6541 not_found_em:
6542         em->block_start = EXTENT_MAP_HOLE;
6543         set_bit(EXTENT_FLAG_VACANCY, &em->flags);
6544 insert:
6545         btrfs_release_path(path);
6546         if (em->start > start || extent_map_end(em) <= start) {
6547                 btrfs_err(root->fs_info, "bad extent! em: [%llu %llu] passed [%llu %llu]",
6548                         em->start, em->len, start, len);
6549                 err = -EIO;
6550                 goto out;
6551         }
6552
6553         err = 0;
6554         write_lock(&em_tree->lock);
6555         ret = add_extent_mapping(em_tree, em, 0);
6556         /* it is possible that someone inserted the extent into the tree
6557          * while we had the lock dropped.  It is also possible that
6558          * an overlapping map exists in the tree
6559          */
6560         if (ret == -EEXIST) {
6561                 struct extent_map *existing;
6562
6563                 ret = 0;
6564
6565                 existing = search_extent_mapping(em_tree, start, len);
6566                 /*
6567                  * existing will always be non-NULL, since there must be
6568                  * extent causing the -EEXIST.
6569                  */
6570                 if (start >= extent_map_end(existing) ||
6571                     start <= existing->start) {
6572                         /*
6573                          * The existing extent map is the one nearest to
6574                          * the [start, start + len) range which overlaps
6575                          */
6576                         err = merge_extent_mapping(em_tree, existing,
6577                                                    em, start);
6578                         free_extent_map(existing);
6579                         if (err) {
6580                                 free_extent_map(em);
6581                                 em = NULL;
6582                         }
6583                 } else {
6584                         free_extent_map(em);
6585                         em = existing;
6586                         err = 0;
6587                 }
6588         }
6589         write_unlock(&em_tree->lock);
6590 out:
6591
6592         trace_btrfs_get_extent(root, em);
6593
6594         if (path)
6595                 btrfs_free_path(path);
6596         if (trans) {
6597                 ret = btrfs_end_transaction(trans, root);
6598                 if (!err)
6599                         err = ret;
6600         }
6601         if (err) {
6602                 free_extent_map(em);
6603                 return ERR_PTR(err);
6604         }
6605         BUG_ON(!em); /* Error is always set */
6606         return em;
6607 }
6608
6609 struct extent_map *btrfs_get_extent_fiemap(struct inode *inode, struct page *page,
6610                                            size_t pg_offset, u64 start, u64 len,
6611                                            int create)
6612 {
6613         struct extent_map *em;
6614         struct extent_map *hole_em = NULL;
6615         u64 range_start = start;
6616         u64 end;
6617         u64 found;
6618         u64 found_end;
6619         int err = 0;
6620
6621         em = btrfs_get_extent(inode, page, pg_offset, start, len, create);
6622         if (IS_ERR(em))
6623                 return em;
6624         if (em) {
6625                 /*
6626                  * if our em maps to
6627                  * -  a hole or
6628                  * -  a pre-alloc extent,
6629                  * there might actually be delalloc bytes behind it.
6630                  */
6631                 if (em->block_start != EXTENT_MAP_HOLE &&
6632                     !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
6633                         return em;
6634                 else
6635                         hole_em = em;
6636         }
6637
6638         /* check to see if we've wrapped (len == -1 or similar) */
6639         end = start + len;
6640         if (end < start)
6641                 end = (u64)-1;
6642         else
6643                 end -= 1;
6644
6645         em = NULL;
6646
6647         /* ok, we didn't find anything, lets look for delalloc */
6648         found = count_range_bits(&BTRFS_I(inode)->io_tree, &range_start,
6649                                  end, len, EXTENT_DELALLOC, 1);
6650         found_end = range_start + found;
6651         if (found_end < range_start)
6652                 found_end = (u64)-1;
6653
6654         /*
6655          * we didn't find anything useful, return
6656          * the original results from get_extent()
6657          */
6658         if (range_start > end || found_end <= start) {
6659                 em = hole_em;
6660                 hole_em = NULL;
6661                 goto out;
6662         }
6663
6664         /* adjust the range_start to make sure it doesn't
6665          * go backwards from the start they passed in
6666          */
6667         range_start = max(start, range_start);
6668         found = found_end - range_start;
6669
6670         if (found > 0) {
6671                 u64 hole_start = start;
6672                 u64 hole_len = len;
6673
6674                 em = alloc_extent_map();
6675                 if (!em) {
6676                         err = -ENOMEM;
6677                         goto out;
6678                 }
6679                 /*
6680                  * when btrfs_get_extent can't find anything it
6681                  * returns one huge hole
6682                  *
6683                  * make sure what it found really fits our range, and
6684                  * adjust to make sure it is based on the start from
6685                  * the caller
6686                  */
6687                 if (hole_em) {
6688                         u64 calc_end = extent_map_end(hole_em);
6689
6690                         if (calc_end <= start || (hole_em->start > end)) {
6691                                 free_extent_map(hole_em);
6692                                 hole_em = NULL;
6693                         } else {
6694                                 hole_start = max(hole_em->start, start);
6695                                 hole_len = calc_end - hole_start;
6696                         }
6697                 }
6698                 em->bdev = NULL;
6699                 if (hole_em && range_start > hole_start) {
6700                         /* our hole starts before our delalloc, so we
6701                          * have to return just the parts of the hole
6702                          * that go until  the delalloc starts
6703                          */
6704                         em->len = min(hole_len,
6705                                       range_start - hole_start);
6706                         em->start = hole_start;
6707                         em->orig_start = hole_start;
6708                         /*
6709                          * don't adjust block start at all,
6710                          * it is fixed at EXTENT_MAP_HOLE
6711                          */
6712                         em->block_start = hole_em->block_start;
6713                         em->block_len = hole_len;
6714                         if (test_bit(EXTENT_FLAG_PREALLOC, &hole_em->flags))
6715                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
6716                 } else {
6717                         em->start = range_start;
6718                         em->len = found;
6719                         em->orig_start = range_start;
6720                         em->block_start = EXTENT_MAP_DELALLOC;
6721                         em->block_len = found;
6722                 }
6723         } else if (hole_em) {
6724                 return hole_em;
6725         }
6726 out:
6727
6728         free_extent_map(hole_em);
6729         if (err) {
6730                 free_extent_map(em);
6731                 return ERR_PTR(err);
6732         }
6733         return em;
6734 }
6735
6736 static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
6737                                                   u64 start, u64 len)
6738 {
6739         struct btrfs_root *root = BTRFS_I(inode)->root;
6740         struct extent_map *em;
6741         struct btrfs_key ins;
6742         u64 alloc_hint;
6743         int ret;
6744
6745         alloc_hint = get_extent_allocation_hint(inode, start, len);
6746         ret = btrfs_reserve_extent(root, len, root->sectorsize, 0,
6747                                    alloc_hint, &ins, 1, 1);
6748         if (ret)
6749                 return ERR_PTR(ret);
6750
6751         em = create_pinned_em(inode, start, ins.offset, start, ins.objectid,
6752                               ins.offset, ins.offset, ins.offset, 0);
6753         if (IS_ERR(em)) {
6754                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
6755                 return em;
6756         }
6757
6758         ret = btrfs_add_ordered_extent_dio(inode, start, ins.objectid,
6759                                            ins.offset, ins.offset, 0);
6760         if (ret) {
6761                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
6762                 free_extent_map(em);
6763                 return ERR_PTR(ret);
6764         }
6765
6766         return em;
6767 }
6768
6769 /*
6770  * returns 1 when the nocow is safe, < 1 on error, 0 if the
6771  * block must be cow'd
6772  */
6773 noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
6774                               u64 *orig_start, u64 *orig_block_len,
6775                               u64 *ram_bytes)
6776 {
6777         struct btrfs_trans_handle *trans;
6778         struct btrfs_path *path;
6779         int ret;
6780         struct extent_buffer *leaf;
6781         struct btrfs_root *root = BTRFS_I(inode)->root;
6782         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
6783         struct btrfs_file_extent_item *fi;
6784         struct btrfs_key key;
6785         u64 disk_bytenr;
6786         u64 backref_offset;
6787         u64 extent_end;
6788         u64 num_bytes;
6789         int slot;
6790         int found_type;
6791         bool nocow = (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW);
6792
6793         path = btrfs_alloc_path();
6794         if (!path)
6795                 return -ENOMEM;
6796
6797         ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(inode),
6798                                        offset, 0);
6799         if (ret < 0)
6800                 goto out;
6801
6802         slot = path->slots[0];
6803         if (ret == 1) {
6804                 if (slot == 0) {
6805                         /* can't find the item, must cow */
6806                         ret = 0;
6807                         goto out;
6808                 }
6809                 slot--;
6810         }
6811         ret = 0;
6812         leaf = path->nodes[0];
6813         btrfs_item_key_to_cpu(leaf, &key, slot);
6814         if (key.objectid != btrfs_ino(inode) ||
6815             key.type != BTRFS_EXTENT_DATA_KEY) {
6816                 /* not our file or wrong item type, must cow */
6817                 goto out;
6818         }
6819
6820         if (key.offset > offset) {
6821                 /* Wrong offset, must cow */
6822                 goto out;
6823         }
6824
6825         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
6826         found_type = btrfs_file_extent_type(leaf, fi);
6827         if (found_type != BTRFS_FILE_EXTENT_REG &&
6828             found_type != BTRFS_FILE_EXTENT_PREALLOC) {
6829                 /* not a regular extent, must cow */
6830                 goto out;
6831         }
6832
6833         if (!nocow && found_type == BTRFS_FILE_EXTENT_REG)
6834                 goto out;
6835
6836         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
6837         if (extent_end <= offset)
6838                 goto out;
6839
6840         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
6841         if (disk_bytenr == 0)
6842                 goto out;
6843
6844         if (btrfs_file_extent_compression(leaf, fi) ||
6845             btrfs_file_extent_encryption(leaf, fi) ||
6846             btrfs_file_extent_other_encoding(leaf, fi))
6847                 goto out;
6848
6849         backref_offset = btrfs_file_extent_offset(leaf, fi);
6850
6851         if (orig_start) {
6852                 *orig_start = key.offset - backref_offset;
6853                 *orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi);
6854                 *ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
6855         }
6856
6857         if (btrfs_extent_readonly(root, disk_bytenr))
6858                 goto out;
6859
6860         num_bytes = min(offset + *len, extent_end) - offset;
6861         if (!nocow && found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6862                 u64 range_end;
6863
6864                 range_end = round_up(offset + num_bytes, root->sectorsize) - 1;
6865                 ret = test_range_bit(io_tree, offset, range_end,
6866                                      EXTENT_DELALLOC, 0, NULL);
6867                 if (ret) {
6868                         ret = -EAGAIN;
6869                         goto out;
6870                 }
6871         }
6872
6873         btrfs_release_path(path);
6874
6875         /*
6876          * look for other files referencing this extent, if we
6877          * find any we must cow
6878          */
6879         trans = btrfs_join_transaction(root);
6880         if (IS_ERR(trans)) {
6881                 ret = 0;
6882                 goto out;
6883         }
6884
6885         ret = btrfs_cross_ref_exist(trans, root, btrfs_ino(inode),
6886                                     key.offset - backref_offset, disk_bytenr);
6887         btrfs_end_transaction(trans, root);
6888         if (ret) {
6889                 ret = 0;
6890                 goto out;
6891         }
6892
6893         /*
6894          * adjust disk_bytenr and num_bytes to cover just the bytes
6895          * in this extent we are about to write.  If there
6896          * are any csums in that range we have to cow in order
6897          * to keep the csums correct
6898          */
6899         disk_bytenr += backref_offset;
6900         disk_bytenr += offset - key.offset;
6901         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
6902                                 goto out;
6903         /*
6904          * all of the above have passed, it is safe to overwrite this extent
6905          * without cow
6906          */
6907         *len = num_bytes;
6908         ret = 1;
6909 out:
6910         btrfs_free_path(path);
6911         return ret;
6912 }
6913
6914 bool btrfs_page_exists_in_range(struct inode *inode, loff_t start, loff_t end)
6915 {
6916         struct radix_tree_root *root = &inode->i_mapping->page_tree;
6917         int found = false;
6918         void **pagep = NULL;
6919         struct page *page = NULL;
6920         int start_idx;
6921         int end_idx;
6922
6923         start_idx = start >> PAGE_CACHE_SHIFT;
6924
6925         /*
6926          * end is the last byte in the last page.  end == start is legal
6927          */
6928         end_idx = end >> PAGE_CACHE_SHIFT;
6929
6930         rcu_read_lock();
6931
6932         /* Most of the code in this while loop is lifted from
6933          * find_get_page.  It's been modified to begin searching from a
6934          * page and return just the first page found in that range.  If the
6935          * found idx is less than or equal to the end idx then we know that
6936          * a page exists.  If no pages are found or if those pages are
6937          * outside of the range then we're fine (yay!) */
6938         while (page == NULL &&
6939                radix_tree_gang_lookup_slot(root, &pagep, NULL, start_idx, 1)) {
6940                 page = radix_tree_deref_slot(pagep);
6941                 if (unlikely(!page))
6942                         break;
6943
6944                 if (radix_tree_exception(page)) {
6945                         if (radix_tree_deref_retry(page)) {
6946                                 page = NULL;
6947                                 continue;
6948                         }
6949                         /*
6950                          * Otherwise, shmem/tmpfs must be storing a swap entry
6951                          * here as an exceptional entry: so return it without
6952                          * attempting to raise page count.
6953                          */
6954                         page = NULL;
6955                         break; /* TODO: Is this relevant for this use case? */
6956                 }
6957
6958                 if (!page_cache_get_speculative(page)) {
6959                         page = NULL;
6960                         continue;
6961                 }
6962
6963                 /*
6964                  * Has the page moved?
6965                  * This is part of the lockless pagecache protocol. See
6966                  * include/linux/pagemap.h for details.
6967                  */
6968                 if (unlikely(page != *pagep)) {
6969                         page_cache_release(page);
6970                         page = NULL;
6971                 }
6972         }
6973
6974         if (page) {
6975                 if (page->index <= end_idx)
6976                         found = true;
6977                 page_cache_release(page);
6978         }
6979
6980         rcu_read_unlock();
6981         return found;
6982 }
6983
6984 static int lock_extent_direct(struct inode *inode, u64 lockstart, u64 lockend,
6985                               struct extent_state **cached_state, int writing)
6986 {
6987         struct btrfs_ordered_extent *ordered;
6988         int ret = 0;
6989
6990         while (1) {
6991                 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
6992                                  0, cached_state);
6993                 /*
6994                  * We're concerned with the entire range that we're going to be
6995                  * doing DIO to, so we need to make sure theres no ordered
6996                  * extents in this range.
6997                  */
6998                 ordered = btrfs_lookup_ordered_range(inode, lockstart,
6999                                                      lockend - lockstart + 1);
7000
7001                 /*
7002                  * We need to make sure there are no buffered pages in this
7003                  * range either, we could have raced between the invalidate in
7004                  * generic_file_direct_write and locking the extent.  The
7005                  * invalidate needs to happen so that reads after a write do not
7006                  * get stale data.
7007                  */
7008                 if (!ordered &&
7009                     (!writing ||
7010                      !btrfs_page_exists_in_range(inode, lockstart, lockend)))
7011                         break;
7012
7013                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7014                                      cached_state, GFP_NOFS);
7015
7016                 if (ordered) {
7017                         btrfs_start_ordered_extent(inode, ordered, 1);
7018                         btrfs_put_ordered_extent(ordered);
7019                 } else {
7020                         /* Screw you mmap */
7021                         ret = filemap_write_and_wait_range(inode->i_mapping,
7022                                                            lockstart,
7023                                                            lockend);
7024                         if (ret)
7025                                 break;
7026
7027                         /*
7028                          * If we found a page that couldn't be invalidated just
7029                          * fall back to buffered.
7030                          */
7031                         ret = invalidate_inode_pages2_range(inode->i_mapping,
7032                                         lockstart >> PAGE_CACHE_SHIFT,
7033                                         lockend >> PAGE_CACHE_SHIFT);
7034                         if (ret)
7035                                 break;
7036                 }
7037
7038                 cond_resched();
7039         }
7040
7041         return ret;
7042 }
7043
7044 static struct extent_map *create_pinned_em(struct inode *inode, u64 start,
7045                                            u64 len, u64 orig_start,
7046                                            u64 block_start, u64 block_len,
7047                                            u64 orig_block_len, u64 ram_bytes,
7048                                            int type)
7049 {
7050         struct extent_map_tree *em_tree;
7051         struct extent_map *em;
7052         struct btrfs_root *root = BTRFS_I(inode)->root;
7053         int ret;
7054
7055         em_tree = &BTRFS_I(inode)->extent_tree;
7056         em = alloc_extent_map();
7057         if (!em)
7058                 return ERR_PTR(-ENOMEM);
7059
7060         em->start = start;
7061         em->orig_start = orig_start;
7062         em->mod_start = start;
7063         em->mod_len = len;
7064         em->len = len;
7065         em->block_len = block_len;
7066         em->block_start = block_start;
7067         em->bdev = root->fs_info->fs_devices->latest_bdev;
7068         em->orig_block_len = orig_block_len;
7069         em->ram_bytes = ram_bytes;
7070         em->generation = -1;
7071         set_bit(EXTENT_FLAG_PINNED, &em->flags);
7072         if (type == BTRFS_ORDERED_PREALLOC)
7073                 set_bit(EXTENT_FLAG_FILLING, &em->flags);
7074
7075         do {
7076                 btrfs_drop_extent_cache(inode, em->start,
7077                                 em->start + em->len - 1, 0);
7078                 write_lock(&em_tree->lock);
7079                 ret = add_extent_mapping(em_tree, em, 1);
7080                 write_unlock(&em_tree->lock);
7081         } while (ret == -EEXIST);
7082
7083         if (ret) {
7084                 free_extent_map(em);
7085                 return ERR_PTR(ret);
7086         }
7087
7088         return em;
7089 }
7090
7091
7092 static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
7093                                    struct buffer_head *bh_result, int create)
7094 {
7095         struct extent_map *em;
7096         struct btrfs_root *root = BTRFS_I(inode)->root;
7097         struct extent_state *cached_state = NULL;
7098         u64 start = iblock << inode->i_blkbits;
7099         u64 lockstart, lockend;
7100         u64 len = bh_result->b_size;
7101         int unlock_bits = EXTENT_LOCKED;
7102         int ret = 0;
7103
7104         if (create)
7105                 unlock_bits |= EXTENT_DELALLOC | EXTENT_DIRTY;
7106         else
7107                 len = min_t(u64, len, root->sectorsize);
7108
7109         lockstart = start;
7110         lockend = start + len - 1;
7111
7112         /*
7113          * If this errors out it's because we couldn't invalidate pagecache for
7114          * this range and we need to fallback to buffered.
7115          */
7116         if (lock_extent_direct(inode, lockstart, lockend, &cached_state, create))
7117                 return -ENOTBLK;
7118
7119         em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
7120         if (IS_ERR(em)) {
7121                 ret = PTR_ERR(em);
7122                 goto unlock_err;
7123         }
7124
7125         /*
7126          * Ok for INLINE and COMPRESSED extents we need to fallback on buffered
7127          * io.  INLINE is special, and we could probably kludge it in here, but
7128          * it's still buffered so for safety lets just fall back to the generic
7129          * buffered path.
7130          *
7131          * For COMPRESSED we _have_ to read the entire extent in so we can
7132          * decompress it, so there will be buffering required no matter what we
7133          * do, so go ahead and fallback to buffered.
7134          *
7135          * We return -ENOTBLK because thats what makes DIO go ahead and go back
7136          * to buffered IO.  Don't blame me, this is the price we pay for using
7137          * the generic code.
7138          */
7139         if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) ||
7140             em->block_start == EXTENT_MAP_INLINE) {
7141                 free_extent_map(em);
7142                 ret = -ENOTBLK;
7143                 goto unlock_err;
7144         }
7145
7146         /* Just a good old fashioned hole, return */
7147         if (!create && (em->block_start == EXTENT_MAP_HOLE ||
7148                         test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
7149                 free_extent_map(em);
7150                 goto unlock_err;
7151         }
7152
7153         /*
7154          * We don't allocate a new extent in the following cases
7155          *
7156          * 1) The inode is marked as NODATACOW.  In this case we'll just use the
7157          * existing extent.
7158          * 2) The extent is marked as PREALLOC.  We're good to go here and can
7159          * just use the extent.
7160          *
7161          */
7162         if (!create) {
7163                 len = min(len, em->len - (start - em->start));
7164                 lockstart = start + len;
7165                 goto unlock;
7166         }
7167
7168         if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags) ||
7169             ((BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
7170              em->block_start != EXTENT_MAP_HOLE)) {
7171                 int type;
7172                 int ret;
7173                 u64 block_start, orig_start, orig_block_len, ram_bytes;
7174
7175                 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7176                         type = BTRFS_ORDERED_PREALLOC;
7177                 else
7178                         type = BTRFS_ORDERED_NOCOW;
7179                 len = min(len, em->len - (start - em->start));
7180                 block_start = em->block_start + (start - em->start);
7181
7182                 if (can_nocow_extent(inode, start, &len, &orig_start,
7183                                      &orig_block_len, &ram_bytes) == 1) {
7184                         if (type == BTRFS_ORDERED_PREALLOC) {
7185                                 free_extent_map(em);
7186                                 em = create_pinned_em(inode, start, len,
7187                                                        orig_start,
7188                                                        block_start, len,
7189                                                        orig_block_len,
7190                                                        ram_bytes, type);
7191                                 if (IS_ERR(em)) {
7192                                         ret = PTR_ERR(em);
7193                                         goto unlock_err;
7194                                 }
7195                         }
7196
7197                         ret = btrfs_add_ordered_extent_dio(inode, start,
7198                                            block_start, len, len, type);
7199                         if (ret) {
7200                                 free_extent_map(em);
7201                                 goto unlock_err;
7202                         }
7203                         goto unlock;
7204                 }
7205         }
7206
7207         /*
7208          * this will cow the extent, reset the len in case we changed
7209          * it above
7210          */
7211         len = bh_result->b_size;
7212         free_extent_map(em);
7213         em = btrfs_new_extent_direct(inode, start, len);
7214         if (IS_ERR(em)) {
7215                 ret = PTR_ERR(em);
7216                 goto unlock_err;
7217         }
7218         len = min(len, em->len - (start - em->start));
7219 unlock:
7220         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
7221                 inode->i_blkbits;
7222         bh_result->b_size = len;
7223         bh_result->b_bdev = em->bdev;
7224         set_buffer_mapped(bh_result);
7225         if (create) {
7226                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7227                         set_buffer_new(bh_result);
7228
7229                 /*
7230                  * Need to update the i_size under the extent lock so buffered
7231                  * readers will get the updated i_size when we unlock.
7232                  */
7233                 if (start + len > i_size_read(inode))
7234                         i_size_write(inode, start + len);
7235
7236                 spin_lock(&BTRFS_I(inode)->lock);
7237                 BTRFS_I(inode)->outstanding_extents++;
7238                 spin_unlock(&BTRFS_I(inode)->lock);
7239
7240                 ret = set_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
7241                                      lockstart + len - 1, EXTENT_DELALLOC, NULL,
7242                                      &cached_state, GFP_NOFS);
7243                 BUG_ON(ret);
7244         }
7245
7246         /*
7247          * In the case of write we need to clear and unlock the entire range,
7248          * in the case of read we need to unlock only the end area that we
7249          * aren't using if there is any left over space.
7250          */
7251         if (lockstart < lockend) {
7252                 clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
7253                                  lockend, unlock_bits, 1, 0,
7254                                  &cached_state, GFP_NOFS);
7255         } else {
7256                 free_extent_state(cached_state);
7257         }
7258
7259         free_extent_map(em);
7260
7261         return 0;
7262
7263 unlock_err:
7264         clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7265                          unlock_bits, 1, 0, &cached_state, GFP_NOFS);
7266         return ret;
7267 }
7268
7269 static inline int submit_dio_repair_bio(struct inode *inode, struct bio *bio,
7270                                         int rw, int mirror_num)
7271 {
7272         struct btrfs_root *root = BTRFS_I(inode)->root;
7273         int ret;
7274
7275         BUG_ON(rw & REQ_WRITE);
7276
7277         bio_get(bio);
7278
7279         ret = btrfs_bio_wq_end_io(root->fs_info, bio,
7280                                   BTRFS_WQ_ENDIO_DIO_REPAIR);
7281         if (ret)
7282                 goto err;
7283
7284         ret = btrfs_map_bio(root, rw, bio, mirror_num, 0);
7285 err:
7286         bio_put(bio);
7287         return ret;
7288 }
7289
7290 static int btrfs_check_dio_repairable(struct inode *inode,
7291                                       struct bio *failed_bio,
7292                                       struct io_failure_record *failrec,
7293                                       int failed_mirror)
7294 {
7295         int num_copies;
7296
7297         num_copies = btrfs_num_copies(BTRFS_I(inode)->root->fs_info,
7298                                       failrec->logical, failrec->len);
7299         if (num_copies == 1) {
7300                 /*
7301                  * we only have a single copy of the data, so don't bother with
7302                  * all the retry and error correction code that follows. no
7303                  * matter what the error is, it is very likely to persist.
7304                  */
7305                 pr_debug("Check DIO Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d\n",
7306                          num_copies, failrec->this_mirror, failed_mirror);
7307                 return 0;
7308         }
7309
7310         failrec->failed_mirror = failed_mirror;
7311         failrec->this_mirror++;
7312         if (failrec->this_mirror == failed_mirror)
7313                 failrec->this_mirror++;
7314
7315         if (failrec->this_mirror > num_copies) {
7316                 pr_debug("Check DIO Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d\n",
7317                          num_copies, failrec->this_mirror, failed_mirror);
7318                 return 0;
7319         }
7320
7321         return 1;
7322 }
7323
7324 static int dio_read_error(struct inode *inode, struct bio *failed_bio,
7325                           struct page *page, u64 start, u64 end,
7326                           int failed_mirror, bio_end_io_t *repair_endio,
7327                           void *repair_arg)
7328 {
7329         struct io_failure_record *failrec;
7330         struct bio *bio;
7331         int isector;
7332         int read_mode;
7333         int ret;
7334
7335         BUG_ON(failed_bio->bi_rw & REQ_WRITE);
7336
7337         ret = btrfs_get_io_failure_record(inode, start, end, &failrec);
7338         if (ret)
7339                 return ret;
7340
7341         ret = btrfs_check_dio_repairable(inode, failed_bio, failrec,
7342                                          failed_mirror);
7343         if (!ret) {
7344                 free_io_failure(inode, failrec);
7345                 return -EIO;
7346         }
7347
7348         if (failed_bio->bi_vcnt > 1)
7349                 read_mode = READ_SYNC | REQ_FAILFAST_DEV;
7350         else
7351                 read_mode = READ_SYNC;
7352
7353         isector = start - btrfs_io_bio(failed_bio)->logical;
7354         isector >>= inode->i_sb->s_blocksize_bits;
7355         bio = btrfs_create_repair_bio(inode, failed_bio, failrec, page,
7356                                       0, isector, repair_endio, repair_arg);
7357         if (!bio) {
7358                 free_io_failure(inode, failrec);
7359                 return -EIO;
7360         }
7361
7362         btrfs_debug(BTRFS_I(inode)->root->fs_info,
7363                     "Repair DIO Read Error: submitting new dio read[%#x] to this_mirror=%d, in_validation=%d\n",
7364                     read_mode, failrec->this_mirror, failrec->in_validation);
7365
7366         ret = submit_dio_repair_bio(inode, bio, read_mode,
7367                                     failrec->this_mirror);
7368         if (ret) {
7369                 free_io_failure(inode, failrec);
7370                 bio_put(bio);
7371         }
7372
7373         return ret;
7374 }
7375
7376 struct btrfs_retry_complete {
7377         struct completion done;
7378         struct inode *inode;
7379         u64 start;
7380         int uptodate;
7381 };
7382
7383 static void btrfs_retry_endio_nocsum(struct bio *bio, int err)
7384 {
7385         struct btrfs_retry_complete *done = bio->bi_private;
7386         struct bio_vec *bvec;
7387         int i;
7388
7389         if (err)
7390                 goto end;
7391
7392         done->uptodate = 1;
7393         bio_for_each_segment_all(bvec, bio, i)
7394                 clean_io_failure(done->inode, done->start, bvec->bv_page, 0);
7395 end:
7396         complete(&done->done);
7397         bio_put(bio);
7398 }
7399
7400 static int __btrfs_correct_data_nocsum(struct inode *inode,
7401                                        struct btrfs_io_bio *io_bio)
7402 {
7403         struct bio_vec *bvec;
7404         struct btrfs_retry_complete done;
7405         u64 start;
7406         int i;
7407         int ret;
7408
7409         start = io_bio->logical;
7410         done.inode = inode;
7411
7412         bio_for_each_segment_all(bvec, &io_bio->bio, i) {
7413 try_again:
7414                 done.uptodate = 0;
7415                 done.start = start;
7416                 init_completion(&done.done);
7417
7418                 ret = dio_read_error(inode, &io_bio->bio, bvec->bv_page, start,
7419                                      start + bvec->bv_len - 1,
7420                                      io_bio->mirror_num,
7421                                      btrfs_retry_endio_nocsum, &done);
7422                 if (ret)
7423                         return ret;
7424
7425                 wait_for_completion(&done.done);
7426
7427                 if (!done.uptodate) {
7428                         /* We might have another mirror, so try again */
7429                         goto try_again;
7430                 }
7431
7432                 start += bvec->bv_len;
7433         }
7434
7435         return 0;
7436 }
7437
7438 static void btrfs_retry_endio(struct bio *bio, int err)
7439 {
7440         struct btrfs_retry_complete *done = bio->bi_private;
7441         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
7442         struct bio_vec *bvec;
7443         int uptodate;
7444         int ret;
7445         int i;
7446
7447         if (err)
7448                 goto end;
7449
7450         uptodate = 1;
7451         bio_for_each_segment_all(bvec, bio, i) {
7452                 ret = __readpage_endio_check(done->inode, io_bio, i,
7453                                              bvec->bv_page, 0,
7454                                              done->start, bvec->bv_len);
7455                 if (!ret)
7456                         clean_io_failure(done->inode, done->start,
7457                                          bvec->bv_page, 0);
7458                 else
7459                         uptodate = 0;
7460         }
7461
7462         done->uptodate = uptodate;
7463 end:
7464         complete(&done->done);
7465         bio_put(bio);
7466 }
7467
7468 static int __btrfs_subio_endio_read(struct inode *inode,
7469                                     struct btrfs_io_bio *io_bio, int err)
7470 {
7471         struct bio_vec *bvec;
7472         struct btrfs_retry_complete done;
7473         u64 start;
7474         u64 offset = 0;
7475         int i;
7476         int ret;
7477
7478         err = 0;
7479         start = io_bio->logical;
7480         done.inode = inode;
7481
7482         bio_for_each_segment_all(bvec, &io_bio->bio, i) {
7483                 ret = __readpage_endio_check(inode, io_bio, i, bvec->bv_page,
7484                                              0, start, bvec->bv_len);
7485                 if (likely(!ret))
7486                         goto next;
7487 try_again:
7488                 done.uptodate = 0;
7489                 done.start = start;
7490                 init_completion(&done.done);
7491
7492                 ret = dio_read_error(inode, &io_bio->bio, bvec->bv_page, start,
7493                                      start + bvec->bv_len - 1,
7494                                      io_bio->mirror_num,
7495                                      btrfs_retry_endio, &done);
7496                 if (ret) {
7497                         err = ret;
7498                         goto next;
7499                 }
7500
7501                 wait_for_completion(&done.done);
7502
7503                 if (!done.uptodate) {
7504                         /* We might have another mirror, so try again */
7505                         goto try_again;
7506                 }
7507 next:
7508                 offset += bvec->bv_len;
7509                 start += bvec->bv_len;
7510         }
7511
7512         return err;
7513 }
7514
7515 static int btrfs_subio_endio_read(struct inode *inode,
7516                                   struct btrfs_io_bio *io_bio, int err)
7517 {
7518         bool skip_csum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
7519
7520         if (skip_csum) {
7521                 if (unlikely(err))
7522                         return __btrfs_correct_data_nocsum(inode, io_bio);
7523                 else
7524                         return 0;
7525         } else {
7526                 return __btrfs_subio_endio_read(inode, io_bio, err);
7527         }
7528 }
7529
7530 static void btrfs_endio_direct_read(struct bio *bio, int err)
7531 {
7532         struct btrfs_dio_private *dip = bio->bi_private;
7533         struct inode *inode = dip->inode;
7534         struct bio *dio_bio;
7535         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
7536
7537         if (dip->flags & BTRFS_DIO_ORIG_BIO_SUBMITTED)
7538                 err = btrfs_subio_endio_read(inode, io_bio, err);
7539
7540         unlock_extent(&BTRFS_I(inode)->io_tree, dip->logical_offset,
7541                       dip->logical_offset + dip->bytes - 1);
7542         dio_bio = dip->dio_bio;
7543
7544         kfree(dip);
7545
7546         /* If we had a csum failure make sure to clear the uptodate flag */
7547         if (err)
7548                 clear_bit(BIO_UPTODATE, &dio_bio->bi_flags);
7549         dio_end_io(dio_bio, err);
7550
7551         if (io_bio->end_io)
7552                 io_bio->end_io(io_bio, err);
7553         bio_put(bio);
7554 }
7555
7556 static void btrfs_endio_direct_write(struct bio *bio, int err)
7557 {
7558         struct btrfs_dio_private *dip = bio->bi_private;
7559         struct inode *inode = dip->inode;
7560         struct btrfs_root *root = BTRFS_I(inode)->root;
7561         struct btrfs_ordered_extent *ordered = NULL;
7562         u64 ordered_offset = dip->logical_offset;
7563         u64 ordered_bytes = dip->bytes;
7564         struct bio *dio_bio;
7565         int ret;
7566
7567         if (err)
7568                 goto out_done;
7569 again:
7570         ret = btrfs_dec_test_first_ordered_pending(inode, &ordered,
7571                                                    &ordered_offset,
7572                                                    ordered_bytes, !err);
7573         if (!ret)
7574                 goto out_test;
7575
7576         btrfs_init_work(&ordered->work, btrfs_endio_write_helper,
7577                         finish_ordered_fn, NULL, NULL);
7578         btrfs_queue_work(root->fs_info->endio_write_workers,
7579                          &ordered->work);
7580 out_test:
7581         /*
7582          * our bio might span multiple ordered extents.  If we haven't
7583          * completed the accounting for the whole dio, go back and try again
7584          */
7585         if (ordered_offset < dip->logical_offset + dip->bytes) {
7586                 ordered_bytes = dip->logical_offset + dip->bytes -
7587                         ordered_offset;
7588                 ordered = NULL;
7589                 goto again;
7590         }
7591 out_done:
7592         dio_bio = dip->dio_bio;
7593
7594         kfree(dip);
7595
7596         /* If we had an error make sure to clear the uptodate flag */
7597         if (err)
7598                 clear_bit(BIO_UPTODATE, &dio_bio->bi_flags);
7599         dio_end_io(dio_bio, err);
7600         bio_put(bio);
7601 }
7602
7603 static int __btrfs_submit_bio_start_direct_io(struct inode *inode, int rw,
7604                                     struct bio *bio, int mirror_num,
7605                                     unsigned long bio_flags, u64 offset)
7606 {
7607         int ret;
7608         struct btrfs_root *root = BTRFS_I(inode)->root;
7609         ret = btrfs_csum_one_bio(root, inode, bio, offset, 1);
7610         BUG_ON(ret); /* -ENOMEM */
7611         return 0;
7612 }
7613
7614 static void btrfs_end_dio_bio(struct bio *bio, int err)
7615 {
7616         struct btrfs_dio_private *dip = bio->bi_private;
7617
7618         if (err)
7619                 btrfs_warn(BTRFS_I(dip->inode)->root->fs_info,
7620                            "direct IO failed ino %llu rw %lu sector %#Lx len %u err no %d",
7621                            btrfs_ino(dip->inode), bio->bi_rw,
7622                            (unsigned long long)bio->bi_iter.bi_sector,
7623                            bio->bi_iter.bi_size, err);
7624
7625         if (dip->subio_endio)
7626                 err = dip->subio_endio(dip->inode, btrfs_io_bio(bio), err);
7627
7628         if (err) {
7629                 dip->errors = 1;
7630
7631                 /*
7632                  * before atomic variable goto zero, we must make sure
7633                  * dip->errors is perceived to be set.
7634                  */
7635                 smp_mb__before_atomic();
7636         }
7637
7638         /* if there are more bios still pending for this dio, just exit */
7639         if (!atomic_dec_and_test(&dip->pending_bios))
7640                 goto out;
7641
7642         if (dip->errors) {
7643                 bio_io_error(dip->orig_bio);
7644         } else {
7645                 set_bit(BIO_UPTODATE, &dip->dio_bio->bi_flags);
7646                 bio_endio(dip->orig_bio, 0);
7647         }
7648 out:
7649         bio_put(bio);
7650 }
7651
7652 static struct bio *btrfs_dio_bio_alloc(struct block_device *bdev,
7653                                        u64 first_sector, gfp_t gfp_flags)
7654 {
7655         int nr_vecs = bio_get_nr_vecs(bdev);
7656         return btrfs_bio_alloc(bdev, first_sector, nr_vecs, gfp_flags);
7657 }
7658
7659 static inline int btrfs_lookup_and_bind_dio_csum(struct btrfs_root *root,
7660                                                  struct inode *inode,
7661                                                  struct btrfs_dio_private *dip,
7662                                                  struct bio *bio,
7663                                                  u64 file_offset)
7664 {
7665         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
7666         struct btrfs_io_bio *orig_io_bio = btrfs_io_bio(dip->orig_bio);
7667         int ret;
7668
7669         /*
7670          * We load all the csum data we need when we submit
7671          * the first bio to reduce the csum tree search and
7672          * contention.
7673          */
7674         if (dip->logical_offset == file_offset) {
7675                 ret = btrfs_lookup_bio_sums_dio(root, inode, dip->orig_bio,
7676                                                 file_offset);
7677                 if (ret)
7678                         return ret;
7679         }
7680
7681         if (bio == dip->orig_bio)
7682                 return 0;
7683
7684         file_offset -= dip->logical_offset;
7685         file_offset >>= inode->i_sb->s_blocksize_bits;
7686         io_bio->csum = (u8 *)(((u32 *)orig_io_bio->csum) + file_offset);
7687
7688         return 0;
7689 }
7690
7691 static inline int __btrfs_submit_dio_bio(struct bio *bio, struct inode *inode,
7692                                          int rw, u64 file_offset, int skip_sum,
7693                                          int async_submit)
7694 {
7695         struct btrfs_dio_private *dip = bio->bi_private;
7696         int write = rw & REQ_WRITE;
7697         struct btrfs_root *root = BTRFS_I(inode)->root;
7698         int ret;
7699
7700         if (async_submit)
7701                 async_submit = !atomic_read(&BTRFS_I(inode)->sync_writers);
7702
7703         bio_get(bio);
7704
7705         if (!write) {
7706                 ret = btrfs_bio_wq_end_io(root->fs_info, bio,
7707                                 BTRFS_WQ_ENDIO_DATA);
7708                 if (ret)
7709                         goto err;
7710         }
7711
7712         if (skip_sum)
7713                 goto map;
7714
7715         if (write && async_submit) {
7716                 ret = btrfs_wq_submit_bio(root->fs_info,
7717                                    inode, rw, bio, 0, 0,
7718                                    file_offset,
7719                                    __btrfs_submit_bio_start_direct_io,
7720                                    __btrfs_submit_bio_done);
7721                 goto err;
7722         } else if (write) {
7723                 /*
7724                  * If we aren't doing async submit, calculate the csum of the
7725                  * bio now.
7726                  */
7727                 ret = btrfs_csum_one_bio(root, inode, bio, file_offset, 1);
7728                 if (ret)
7729                         goto err;
7730         } else {
7731                 ret = btrfs_lookup_and_bind_dio_csum(root, inode, dip, bio,
7732                                                      file_offset);
7733                 if (ret)
7734                         goto err;
7735         }
7736 map:
7737         ret = btrfs_map_bio(root, rw, bio, 0, async_submit);
7738 err:
7739         bio_put(bio);
7740         return ret;
7741 }
7742
7743 static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip,
7744                                     int skip_sum)
7745 {
7746         struct inode *inode = dip->inode;
7747         struct btrfs_root *root = BTRFS_I(inode)->root;
7748         struct bio *bio;
7749         struct bio *orig_bio = dip->orig_bio;
7750         struct bio_vec *bvec = orig_bio->bi_io_vec;
7751         u64 start_sector = orig_bio->bi_iter.bi_sector;
7752         u64 file_offset = dip->logical_offset;
7753         u64 submit_len = 0;
7754         u64 map_length;
7755         int nr_pages = 0;
7756         int ret;
7757         int async_submit = 0;
7758
7759         map_length = orig_bio->bi_iter.bi_size;
7760         ret = btrfs_map_block(root->fs_info, rw, start_sector << 9,
7761                               &map_length, NULL, 0);
7762         if (ret)
7763                 return -EIO;
7764
7765         if (map_length >= orig_bio->bi_iter.bi_size) {
7766                 bio = orig_bio;
7767                 dip->flags |= BTRFS_DIO_ORIG_BIO_SUBMITTED;
7768                 goto submit;
7769         }
7770
7771         /* async crcs make it difficult to collect full stripe writes. */
7772         if (btrfs_get_alloc_profile(root, 1) &
7773             (BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6))
7774                 async_submit = 0;
7775         else
7776                 async_submit = 1;
7777
7778         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev, start_sector, GFP_NOFS);
7779         if (!bio)
7780                 return -ENOMEM;
7781
7782         bio->bi_private = dip;
7783         bio->bi_end_io = btrfs_end_dio_bio;
7784         btrfs_io_bio(bio)->logical = file_offset;
7785         atomic_inc(&dip->pending_bios);
7786
7787         while (bvec <= (orig_bio->bi_io_vec + orig_bio->bi_vcnt - 1)) {
7788                 if (map_length < submit_len + bvec->bv_len ||
7789                     bio_add_page(bio, bvec->bv_page, bvec->bv_len,
7790                                  bvec->bv_offset) < bvec->bv_len) {
7791                         /*
7792                          * inc the count before we submit the bio so
7793                          * we know the end IO handler won't happen before
7794                          * we inc the count. Otherwise, the dip might get freed
7795                          * before we're done setting it up
7796                          */
7797                         atomic_inc(&dip->pending_bios);
7798                         ret = __btrfs_submit_dio_bio(bio, inode, rw,
7799                                                      file_offset, skip_sum,
7800                                                      async_submit);
7801                         if (ret) {
7802                                 bio_put(bio);
7803                                 atomic_dec(&dip->pending_bios);
7804                                 goto out_err;
7805                         }
7806
7807                         start_sector += submit_len >> 9;
7808                         file_offset += submit_len;
7809
7810                         submit_len = 0;
7811                         nr_pages = 0;
7812
7813                         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev,
7814                                                   start_sector, GFP_NOFS);
7815                         if (!bio)
7816                                 goto out_err;
7817                         bio->bi_private = dip;
7818                         bio->bi_end_io = btrfs_end_dio_bio;
7819                         btrfs_io_bio(bio)->logical = file_offset;
7820
7821                         map_length = orig_bio->bi_iter.bi_size;
7822                         ret = btrfs_map_block(root->fs_info, rw,
7823                                               start_sector << 9,
7824                                               &map_length, NULL, 0);
7825                         if (ret) {
7826                                 bio_put(bio);
7827                                 goto out_err;
7828                         }
7829                 } else {
7830                         submit_len += bvec->bv_len;
7831                         nr_pages++;
7832                         bvec++;
7833                 }
7834         }
7835
7836 submit:
7837         ret = __btrfs_submit_dio_bio(bio, inode, rw, file_offset, skip_sum,
7838                                      async_submit);
7839         if (!ret)
7840                 return 0;
7841
7842         bio_put(bio);
7843 out_err:
7844         dip->errors = 1;
7845         /*
7846          * before atomic variable goto zero, we must
7847          * make sure dip->errors is perceived to be set.
7848          */
7849         smp_mb__before_atomic();
7850         if (atomic_dec_and_test(&dip->pending_bios))
7851                 bio_io_error(dip->orig_bio);
7852
7853         /* bio_end_io() will handle error, so we needn't return it */
7854         return 0;
7855 }
7856
7857 static void btrfs_submit_direct(int rw, struct bio *dio_bio,
7858                                 struct inode *inode, loff_t file_offset)
7859 {
7860         struct btrfs_root *root = BTRFS_I(inode)->root;
7861         struct btrfs_dio_private *dip;
7862         struct bio *io_bio;
7863         struct btrfs_io_bio *btrfs_bio;
7864         int skip_sum;
7865         int write = rw & REQ_WRITE;
7866         int ret = 0;
7867
7868         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
7869
7870         io_bio = btrfs_bio_clone(dio_bio, GFP_NOFS);
7871         if (!io_bio) {
7872                 ret = -ENOMEM;
7873                 goto free_ordered;
7874         }
7875
7876         dip = kzalloc(sizeof(*dip), GFP_NOFS);
7877         if (!dip) {
7878                 ret = -ENOMEM;
7879                 goto free_io_bio;
7880         }
7881
7882         dip->private = dio_bio->bi_private;
7883         dip->inode = inode;
7884         dip->logical_offset = file_offset;
7885         dip->bytes = dio_bio->bi_iter.bi_size;
7886         dip->disk_bytenr = (u64)dio_bio->bi_iter.bi_sector << 9;
7887         io_bio->bi_private = dip;
7888         dip->orig_bio = io_bio;
7889         dip->dio_bio = dio_bio;
7890         atomic_set(&dip->pending_bios, 0);
7891         btrfs_bio = btrfs_io_bio(io_bio);
7892         btrfs_bio->logical = file_offset;
7893
7894         if (write) {
7895                 io_bio->bi_end_io = btrfs_endio_direct_write;
7896         } else {
7897                 io_bio->bi_end_io = btrfs_endio_direct_read;
7898                 dip->subio_endio = btrfs_subio_endio_read;
7899         }
7900
7901         ret = btrfs_submit_direct_hook(rw, dip, skip_sum);
7902         if (!ret)
7903                 return;
7904
7905         if (btrfs_bio->end_io)
7906                 btrfs_bio->end_io(btrfs_bio, ret);
7907 free_io_bio:
7908         bio_put(io_bio);
7909
7910 free_ordered:
7911         /*
7912          * If this is a write, we need to clean up the reserved space and kill
7913          * the ordered extent.
7914          */
7915         if (write) {
7916                 struct btrfs_ordered_extent *ordered;
7917                 ordered = btrfs_lookup_ordered_extent(inode, file_offset);
7918                 if (!test_bit(BTRFS_ORDERED_PREALLOC, &ordered->flags) &&
7919                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered->flags))
7920                         btrfs_free_reserved_extent(root, ordered->start,
7921                                                    ordered->disk_len, 1);
7922                 btrfs_put_ordered_extent(ordered);
7923                 btrfs_put_ordered_extent(ordered);
7924         }
7925         bio_endio(dio_bio, ret);
7926 }
7927
7928 static ssize_t check_direct_IO(struct btrfs_root *root, int rw, struct kiocb *iocb,
7929                         const struct iov_iter *iter, loff_t offset)
7930 {
7931         int seg;
7932         int i;
7933         unsigned blocksize_mask = root->sectorsize - 1;
7934         ssize_t retval = -EINVAL;
7935
7936         if (offset & blocksize_mask)
7937                 goto out;
7938
7939         if (iov_iter_alignment(iter) & blocksize_mask)
7940                 goto out;
7941
7942         /* If this is a write we don't need to check anymore */
7943         if (rw & WRITE)
7944                 return 0;
7945         /*
7946          * Check to make sure we don't have duplicate iov_base's in this
7947          * iovec, if so return EINVAL, otherwise we'll get csum errors
7948          * when reading back.
7949          */
7950         for (seg = 0; seg < iter->nr_segs; seg++) {
7951                 for (i = seg + 1; i < iter->nr_segs; i++) {
7952                         if (iter->iov[seg].iov_base == iter->iov[i].iov_base)
7953                                 goto out;
7954                 }
7955         }
7956         retval = 0;
7957 out:
7958         return retval;
7959 }
7960
7961 static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
7962                         struct iov_iter *iter, loff_t offset)
7963 {
7964         struct file *file = iocb->ki_filp;
7965         struct inode *inode = file->f_mapping->host;
7966         size_t count = 0;
7967         int flags = 0;
7968         bool wakeup = true;
7969         bool relock = false;
7970         ssize_t ret;
7971
7972         if (check_direct_IO(BTRFS_I(inode)->root, rw, iocb, iter, offset))
7973                 return 0;
7974
7975         atomic_inc(&inode->i_dio_count);
7976         smp_mb__after_atomic();
7977
7978         /*
7979          * The generic stuff only does filemap_write_and_wait_range, which
7980          * isn't enough if we've written compressed pages to this area, so
7981          * we need to flush the dirty pages again to make absolutely sure
7982          * that any outstanding dirty pages are on disk.
7983          */
7984         count = iov_iter_count(iter);
7985         if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
7986                      &BTRFS_I(inode)->runtime_flags))
7987                 filemap_fdatawrite_range(inode->i_mapping, offset,
7988                                          offset + count - 1);
7989
7990         if (rw & WRITE) {
7991                 /*
7992                  * If the write DIO is beyond the EOF, we need update
7993                  * the isize, but it is protected by i_mutex. So we can
7994                  * not unlock the i_mutex at this case.
7995                  */
7996                 if (offset + count <= inode->i_size) {
7997                         mutex_unlock(&inode->i_mutex);
7998                         relock = true;
7999                 }
8000                 ret = btrfs_delalloc_reserve_space(inode, count);
8001                 if (ret)
8002                         goto out;
8003         } else if (test_bit(BTRFS_INODE_READDIO_NEED_LOCK,
8004                                      &BTRFS_I(inode)->runtime_flags)) {
8005                 inode_dio_done(inode);
8006                 flags = DIO_LOCKING | DIO_SKIP_HOLES;
8007                 wakeup = false;
8008         }
8009
8010         ret = __blockdev_direct_IO(rw, iocb, inode,
8011                         BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev,
8012                         iter, offset, btrfs_get_blocks_direct, NULL,
8013                         btrfs_submit_direct, flags);
8014         if (rw & WRITE) {
8015                 if (ret < 0 && ret != -EIOCBQUEUED)
8016                         btrfs_delalloc_release_space(inode, count);
8017                 else if (ret >= 0 && (size_t)ret < count)
8018                         btrfs_delalloc_release_space(inode,
8019                                                      count - (size_t)ret);
8020                 else
8021                         btrfs_delalloc_release_metadata(inode, 0);
8022         }
8023 out:
8024         if (wakeup)
8025                 inode_dio_done(inode);
8026         if (relock)
8027                 mutex_lock(&inode->i_mutex);
8028
8029         return ret;
8030 }
8031
8032 #define BTRFS_FIEMAP_FLAGS      (FIEMAP_FLAG_SYNC)
8033
8034 static int btrfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
8035                 __u64 start, __u64 len)
8036 {
8037         int     ret;
8038
8039         ret = fiemap_check_flags(fieinfo, BTRFS_FIEMAP_FLAGS);
8040         if (ret)
8041                 return ret;
8042
8043         return extent_fiemap(inode, fieinfo, start, len, btrfs_get_extent_fiemap);
8044 }
8045
8046 int btrfs_readpage(struct file *file, struct page *page)
8047 {
8048         struct extent_io_tree *tree;
8049         tree = &BTRFS_I(page->mapping->host)->io_tree;
8050         return extent_read_full_page(tree, page, btrfs_get_extent, 0);
8051 }
8052
8053 static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
8054 {
8055         struct extent_io_tree *tree;
8056
8057
8058         if (current->flags & PF_MEMALLOC) {
8059                 redirty_page_for_writepage(wbc, page);
8060                 unlock_page(page);
8061                 return 0;
8062         }
8063         tree = &BTRFS_I(page->mapping->host)->io_tree;
8064         return extent_write_full_page(tree, page, btrfs_get_extent, wbc);
8065 }
8066
8067 static int btrfs_writepages(struct address_space *mapping,
8068                             struct writeback_control *wbc)
8069 {
8070         struct extent_io_tree *tree;
8071
8072         tree = &BTRFS_I(mapping->host)->io_tree;
8073         return extent_writepages(tree, mapping, btrfs_get_extent, wbc);
8074 }
8075
8076 static int
8077 btrfs_readpages(struct file *file, struct address_space *mapping,
8078                 struct list_head *pages, unsigned nr_pages)
8079 {
8080         struct extent_io_tree *tree;
8081         tree = &BTRFS_I(mapping->host)->io_tree;
8082         return extent_readpages(tree, mapping, pages, nr_pages,
8083                                 btrfs_get_extent);
8084 }
8085 static int __btrfs_releasepage(struct page *page, gfp_t gfp_flags)
8086 {
8087         struct extent_io_tree *tree;
8088         struct extent_map_tree *map;
8089         int ret;
8090
8091         tree = &BTRFS_I(page->mapping->host)->io_tree;
8092         map = &BTRFS_I(page->mapping->host)->extent_tree;
8093         ret = try_release_extent_mapping(map, tree, page, gfp_flags);
8094         if (ret == 1) {
8095                 ClearPagePrivate(page);
8096                 set_page_private(page, 0);
8097                 page_cache_release(page);
8098         }
8099         return ret;
8100 }
8101
8102 static int btrfs_releasepage(struct page *page, gfp_t gfp_flags)
8103 {
8104         if (PageWriteback(page) || PageDirty(page))
8105                 return 0;
8106         return __btrfs_releasepage(page, gfp_flags & GFP_NOFS);
8107 }
8108
8109 static void btrfs_invalidatepage(struct page *page, unsigned int offset,
8110                                  unsigned int length)
8111 {
8112         struct inode *inode = page->mapping->host;
8113         struct extent_io_tree *tree;
8114         struct btrfs_ordered_extent *ordered;
8115         struct extent_state *cached_state = NULL;
8116         u64 page_start = page_offset(page);
8117         u64 page_end = page_start + PAGE_CACHE_SIZE - 1;
8118         int inode_evicting = inode->i_state & I_FREEING;
8119
8120         /*
8121          * we have the page locked, so new writeback can't start,
8122          * and the dirty bit won't be cleared while we are here.
8123          *
8124          * Wait for IO on this page so that we can safely clear
8125          * the PagePrivate2 bit and do ordered accounting
8126          */
8127         wait_on_page_writeback(page);
8128
8129         tree = &BTRFS_I(inode)->io_tree;
8130         if (offset) {
8131                 btrfs_releasepage(page, GFP_NOFS);
8132                 return;
8133         }
8134
8135         if (!inode_evicting)
8136                 lock_extent_bits(tree, page_start, page_end, 0, &cached_state);
8137         ordered = btrfs_lookup_ordered_extent(inode, page_start);
8138         if (ordered) {
8139                 /*
8140                  * IO on this page will never be started, so we need
8141                  * to account for any ordered extents now
8142                  */
8143                 if (!inode_evicting)
8144                         clear_extent_bit(tree, page_start, page_end,
8145                                          EXTENT_DIRTY | EXTENT_DELALLOC |
8146                                          EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
8147                                          EXTENT_DEFRAG, 1, 0, &cached_state,
8148                                          GFP_NOFS);
8149                 /*
8150                  * whoever cleared the private bit is responsible
8151                  * for the finish_ordered_io
8152                  */
8153                 if (TestClearPagePrivate2(page)) {
8154                         struct btrfs_ordered_inode_tree *tree;
8155                         u64 new_len;
8156
8157                         tree = &BTRFS_I(inode)->ordered_tree;
8158
8159                         spin_lock_irq(&tree->lock);
8160                         set_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags);
8161                         new_len = page_start - ordered->file_offset;
8162                         if (new_len < ordered->truncated_len)
8163                                 ordered->truncated_len = new_len;
8164                         spin_unlock_irq(&tree->lock);
8165
8166                         if (btrfs_dec_test_ordered_pending(inode, &ordered,
8167                                                            page_start,
8168                                                            PAGE_CACHE_SIZE, 1))
8169                                 btrfs_finish_ordered_io(ordered);
8170                 }
8171                 btrfs_put_ordered_extent(ordered);
8172                 if (!inode_evicting) {
8173                         cached_state = NULL;
8174                         lock_extent_bits(tree, page_start, page_end, 0,
8175                                          &cached_state);
8176                 }
8177         }
8178
8179         if (!inode_evicting) {
8180                 clear_extent_bit(tree, page_start, page_end,
8181                                  EXTENT_LOCKED | EXTENT_DIRTY |
8182                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
8183                                  EXTENT_DEFRAG, 1, 1,
8184                                  &cached_state, GFP_NOFS);
8185
8186                 __btrfs_releasepage(page, GFP_NOFS);
8187         }
8188
8189         ClearPageChecked(page);
8190         if (PagePrivate(page)) {
8191                 ClearPagePrivate(page);
8192                 set_page_private(page, 0);
8193                 page_cache_release(page);
8194         }
8195 }
8196
8197 /*
8198  * btrfs_page_mkwrite() is not allowed to change the file size as it gets
8199  * called from a page fault handler when a page is first dirtied. Hence we must
8200  * be careful to check for EOF conditions here. We set the page up correctly
8201  * for a written page which means we get ENOSPC checking when writing into
8202  * holes and correct delalloc and unwritten extent mapping on filesystems that
8203  * support these features.
8204  *
8205  * We are not allowed to take the i_mutex here so we have to play games to
8206  * protect against truncate races as the page could now be beyond EOF.  Because
8207  * vmtruncate() writes the inode size before removing pages, once we have the
8208  * page lock we can determine safely if the page is beyond EOF. If it is not
8209  * beyond EOF, then the page is guaranteed safe against truncation until we
8210  * unlock the page.
8211  */
8212 int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
8213 {
8214         struct page *page = vmf->page;
8215         struct inode *inode = file_inode(vma->vm_file);
8216         struct btrfs_root *root = BTRFS_I(inode)->root;
8217         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
8218         struct btrfs_ordered_extent *ordered;
8219         struct extent_state *cached_state = NULL;
8220         char *kaddr;
8221         unsigned long zero_start;
8222         loff_t size;
8223         int ret;
8224         int reserved = 0;
8225         u64 page_start;
8226         u64 page_end;
8227
8228         sb_start_pagefault(inode->i_sb);
8229         ret  = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
8230         if (!ret) {
8231                 ret = file_update_time(vma->vm_file);
8232                 reserved = 1;
8233         }
8234         if (ret) {
8235                 if (ret == -ENOMEM)
8236                         ret = VM_FAULT_OOM;
8237                 else /* -ENOSPC, -EIO, etc */
8238                         ret = VM_FAULT_SIGBUS;
8239                 if (reserved)
8240                         goto out;
8241                 goto out_noreserve;
8242         }
8243
8244         ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */
8245 again:
8246         lock_page(page);
8247         size = i_size_read(inode);
8248         page_start = page_offset(page);
8249         page_end = page_start + PAGE_CACHE_SIZE - 1;
8250
8251         if ((page->mapping != inode->i_mapping) ||
8252             (page_start >= size)) {
8253                 /* page got truncated out from underneath us */
8254                 goto out_unlock;
8255         }
8256         wait_on_page_writeback(page);
8257
8258         lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state);
8259         set_page_extent_mapped(page);
8260
8261         /*
8262          * we can't set the delalloc bits if there are pending ordered
8263          * extents.  Drop our locks and wait for them to finish
8264          */
8265         ordered = btrfs_lookup_ordered_extent(inode, page_start);
8266         if (ordered) {
8267                 unlock_extent_cached(io_tree, page_start, page_end,
8268                                      &cached_state, GFP_NOFS);
8269                 unlock_page(page);
8270                 btrfs_start_ordered_extent(inode, ordered, 1);
8271                 btrfs_put_ordered_extent(ordered);
8272                 goto again;
8273         }
8274
8275         /*
8276          * XXX - page_mkwrite gets called every time the page is dirtied, even
8277          * if it was already dirty, so for space accounting reasons we need to
8278          * clear any delalloc bits for the range we are fixing to save.  There
8279          * is probably a better way to do this, but for now keep consistent with
8280          * prepare_pages in the normal write path.
8281          */
8282         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
8283                           EXTENT_DIRTY | EXTENT_DELALLOC |
8284                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
8285                           0, 0, &cached_state, GFP_NOFS);
8286
8287         ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
8288                                         &cached_state);
8289         if (ret) {
8290                 unlock_extent_cached(io_tree, page_start, page_end,
8291                                      &cached_state, GFP_NOFS);
8292                 ret = VM_FAULT_SIGBUS;
8293                 goto out_unlock;
8294         }
8295         ret = 0;
8296
8297         /* page is wholly or partially inside EOF */
8298         if (page_start + PAGE_CACHE_SIZE > size)
8299                 zero_start = size & ~PAGE_CACHE_MASK;
8300         else
8301                 zero_start = PAGE_CACHE_SIZE;
8302
8303         if (zero_start != PAGE_CACHE_SIZE) {
8304                 kaddr = kmap(page);
8305                 memset(kaddr + zero_start, 0, PAGE_CACHE_SIZE - zero_start);
8306                 flush_dcache_page(page);
8307                 kunmap(page);
8308         }
8309         ClearPageChecked(page);
8310         set_page_dirty(page);
8311         SetPageUptodate(page);
8312
8313         BTRFS_I(inode)->last_trans = root->fs_info->generation;
8314         BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid;
8315         BTRFS_I(inode)->last_log_commit = BTRFS_I(inode)->root->last_log_commit;
8316
8317         unlock_extent_cached(io_tree, page_start, page_end, &cached_state, GFP_NOFS);
8318
8319 out_unlock:
8320         if (!ret) {
8321                 sb_end_pagefault(inode->i_sb);
8322                 return VM_FAULT_LOCKED;
8323         }
8324         unlock_page(page);
8325 out:
8326         btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
8327 out_noreserve:
8328         sb_end_pagefault(inode->i_sb);
8329         return ret;
8330 }
8331
8332 static int btrfs_truncate(struct inode *inode)
8333 {
8334         struct btrfs_root *root = BTRFS_I(inode)->root;
8335         struct btrfs_block_rsv *rsv;
8336         int ret = 0;
8337         int err = 0;
8338         struct btrfs_trans_handle *trans;
8339         u64 mask = root->sectorsize - 1;
8340         u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
8341
8342         ret = btrfs_wait_ordered_range(inode, inode->i_size & (~mask),
8343                                        (u64)-1);
8344         if (ret)
8345                 return ret;
8346
8347         /*
8348          * Yes ladies and gentelment, this is indeed ugly.  The fact is we have
8349          * 3 things going on here
8350          *
8351          * 1) We need to reserve space for our orphan item and the space to
8352          * delete our orphan item.  Lord knows we don't want to have a dangling
8353          * orphan item because we didn't reserve space to remove it.
8354          *
8355          * 2) We need to reserve space to update our inode.
8356          *
8357          * 3) We need to have something to cache all the space that is going to
8358          * be free'd up by the truncate operation, but also have some slack
8359          * space reserved in case it uses space during the truncate (thank you
8360          * very much snapshotting).
8361          *
8362          * And we need these to all be seperate.  The fact is we can use alot of
8363          * space doing the truncate, and we have no earthly idea how much space
8364          * we will use, so we need the truncate reservation to be seperate so it
8365          * doesn't end up using space reserved for updating the inode or
8366          * removing the orphan item.  We also need to be able to stop the
8367          * transaction and start a new one, which means we need to be able to
8368          * update the inode several times, and we have no idea of knowing how
8369          * many times that will be, so we can't just reserve 1 item for the
8370          * entirety of the opration, so that has to be done seperately as well.
8371          * Then there is the orphan item, which does indeed need to be held on
8372          * to for the whole operation, and we need nobody to touch this reserved
8373          * space except the orphan code.
8374          *
8375          * So that leaves us with
8376          *
8377          * 1) root->orphan_block_rsv - for the orphan deletion.
8378          * 2) rsv - for the truncate reservation, which we will steal from the
8379          * transaction reservation.
8380          * 3) fs_info->trans_block_rsv - this will have 1 items worth left for
8381          * updating the inode.
8382          */
8383         rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
8384         if (!rsv)
8385                 return -ENOMEM;
8386         rsv->size = min_size;
8387         rsv->failfast = 1;
8388
8389         /*
8390          * 1 for the truncate slack space
8391          * 1 for updating the inode.
8392          */
8393         trans = btrfs_start_transaction(root, 2);
8394         if (IS_ERR(trans)) {
8395                 err = PTR_ERR(trans);
8396                 goto out;
8397         }
8398
8399         /* Migrate the slack space for the truncate to our reserve */
8400         ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv, rsv,
8401                                       min_size);
8402         BUG_ON(ret);
8403
8404         /*
8405          * So if we truncate and then write and fsync we normally would just
8406          * write the extents that changed, which is a problem if we need to
8407          * first truncate that entire inode.  So set this flag so we write out
8408          * all of the extents in the inode to the sync log so we're completely
8409          * safe.
8410          */
8411         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
8412         trans->block_rsv = rsv;
8413
8414         while (1) {
8415                 ret = btrfs_truncate_inode_items(trans, root, inode,
8416                                                  inode->i_size,
8417                                                  BTRFS_EXTENT_DATA_KEY);
8418                 if (ret != -ENOSPC) {
8419                         err = ret;
8420                         break;
8421                 }
8422
8423                 trans->block_rsv = &root->fs_info->trans_block_rsv;
8424                 ret = btrfs_update_inode(trans, root, inode);
8425                 if (ret) {
8426                         err = ret;
8427                         break;
8428                 }
8429
8430                 btrfs_end_transaction(trans, root);
8431                 btrfs_btree_balance_dirty(root);
8432
8433                 trans = btrfs_start_transaction(root, 2);
8434                 if (IS_ERR(trans)) {
8435                         ret = err = PTR_ERR(trans);
8436                         trans = NULL;
8437                         break;
8438                 }
8439
8440                 ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv,
8441                                               rsv, min_size);
8442                 BUG_ON(ret);    /* shouldn't happen */
8443                 trans->block_rsv = rsv;
8444         }
8445
8446         if (ret == 0 && inode->i_nlink > 0) {
8447                 trans->block_rsv = root->orphan_block_rsv;
8448                 ret = btrfs_orphan_del(trans, inode);
8449                 if (ret)
8450                         err = ret;
8451         }
8452
8453         if (trans) {
8454                 trans->block_rsv = &root->fs_info->trans_block_rsv;
8455                 ret = btrfs_update_inode(trans, root, inode);
8456                 if (ret && !err)
8457                         err = ret;
8458
8459                 ret = btrfs_end_transaction(trans, root);
8460                 btrfs_btree_balance_dirty(root);
8461         }
8462
8463 out:
8464         btrfs_free_block_rsv(root, rsv);
8465
8466         if (ret && !err)
8467                 err = ret;
8468
8469         return err;
8470 }
8471
8472 /*
8473  * create a new subvolume directory/inode (helper for the ioctl).
8474  */
8475 int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
8476                              struct btrfs_root *new_root,
8477                              struct btrfs_root *parent_root,
8478                              u64 new_dirid)
8479 {
8480         struct inode *inode;
8481         int err;
8482         u64 index = 0;
8483
8484         inode = btrfs_new_inode(trans, new_root, NULL, "..", 2,
8485                                 new_dirid, new_dirid,
8486                                 S_IFDIR | (~current_umask() & S_IRWXUGO),
8487                                 &index);
8488         if (IS_ERR(inode))
8489                 return PTR_ERR(inode);
8490         inode->i_op = &btrfs_dir_inode_operations;
8491         inode->i_fop = &btrfs_dir_file_operations;
8492
8493         set_nlink(inode, 1);
8494         btrfs_i_size_write(inode, 0);
8495         unlock_new_inode(inode);
8496
8497         err = btrfs_subvol_inherit_props(trans, new_root, parent_root);
8498         if (err)
8499                 btrfs_err(new_root->fs_info,
8500                           "error inheriting subvolume %llu properties: %d",
8501                           new_root->root_key.objectid, err);
8502
8503         err = btrfs_update_inode(trans, new_root, inode);
8504
8505         iput(inode);
8506         return err;
8507 }
8508
8509 struct inode *btrfs_alloc_inode(struct super_block *sb)
8510 {
8511         struct btrfs_inode *ei;
8512         struct inode *inode;
8513
8514         ei = kmem_cache_alloc(btrfs_inode_cachep, GFP_NOFS);
8515         if (!ei)
8516                 return NULL;
8517
8518         ei->root = NULL;
8519         ei->generation = 0;
8520         ei->last_trans = 0;
8521         ei->last_sub_trans = 0;
8522         ei->logged_trans = 0;
8523         ei->delalloc_bytes = 0;
8524         ei->defrag_bytes = 0;
8525         ei->disk_i_size = 0;
8526         ei->flags = 0;
8527         ei->csum_bytes = 0;
8528         ei->index_cnt = (u64)-1;
8529         ei->dir_index = 0;
8530         ei->last_unlink_trans = 0;
8531         ei->last_log_commit = 0;
8532
8533         spin_lock_init(&ei->lock);
8534         ei->outstanding_extents = 0;
8535         ei->reserved_extents = 0;
8536
8537         ei->runtime_flags = 0;
8538         ei->force_compress = BTRFS_COMPRESS_NONE;
8539
8540         ei->delayed_node = NULL;
8541
8542         inode = &ei->vfs_inode;
8543         extent_map_tree_init(&ei->extent_tree);
8544         extent_io_tree_init(&ei->io_tree, &inode->i_data);
8545         extent_io_tree_init(&ei->io_failure_tree, &inode->i_data);
8546         ei->io_tree.track_uptodate = 1;
8547         ei->io_failure_tree.track_uptodate = 1;
8548         atomic_set(&ei->sync_writers, 0);
8549         mutex_init(&ei->log_mutex);
8550         mutex_init(&ei->delalloc_mutex);
8551         btrfs_ordered_inode_tree_init(&ei->ordered_tree);
8552         INIT_LIST_HEAD(&ei->delalloc_inodes);
8553         RB_CLEAR_NODE(&ei->rb_node);
8554
8555         return inode;
8556 }
8557
8558 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
8559 void btrfs_test_destroy_inode(struct inode *inode)
8560 {
8561         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
8562         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
8563 }
8564 #endif
8565
8566 static void btrfs_i_callback(struct rcu_head *head)
8567 {
8568         struct inode *inode = container_of(head, struct inode, i_rcu);
8569         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
8570 }
8571
8572 void btrfs_destroy_inode(struct inode *inode)
8573 {
8574         struct btrfs_ordered_extent *ordered;
8575         struct btrfs_root *root = BTRFS_I(inode)->root;
8576
8577         WARN_ON(!hlist_empty(&inode->i_dentry));
8578         WARN_ON(inode->i_data.nrpages);
8579         WARN_ON(BTRFS_I(inode)->outstanding_extents);
8580         WARN_ON(BTRFS_I(inode)->reserved_extents);
8581         WARN_ON(BTRFS_I(inode)->delalloc_bytes);
8582         WARN_ON(BTRFS_I(inode)->csum_bytes);
8583         WARN_ON(BTRFS_I(inode)->defrag_bytes);
8584
8585         /*
8586          * This can happen where we create an inode, but somebody else also
8587          * created the same inode and we need to destroy the one we already
8588          * created.
8589          */
8590         if (!root)
8591                 goto free;
8592
8593         if (test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
8594                      &BTRFS_I(inode)->runtime_flags)) {
8595                 btrfs_info(root->fs_info, "inode %llu still on the orphan list",
8596                         btrfs_ino(inode));
8597                 atomic_dec(&root->orphan_inodes);
8598         }
8599
8600         while (1) {
8601                 ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
8602                 if (!ordered)
8603                         break;
8604                 else {
8605                         btrfs_err(root->fs_info, "found ordered extent %llu %llu on inode cleanup",
8606                                 ordered->file_offset, ordered->len);
8607                         btrfs_remove_ordered_extent(inode, ordered);
8608                         btrfs_put_ordered_extent(ordered);
8609                         btrfs_put_ordered_extent(ordered);
8610                 }
8611         }
8612         inode_tree_del(inode);
8613         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
8614 free:
8615         call_rcu(&inode->i_rcu, btrfs_i_callback);
8616 }
8617
8618 int btrfs_drop_inode(struct inode *inode)
8619 {
8620         struct btrfs_root *root = BTRFS_I(inode)->root;
8621
8622         if (root == NULL)
8623                 return 1;
8624
8625         /* the snap/subvol tree is on deleting */
8626         if (btrfs_root_refs(&root->root_item) == 0)
8627                 return 1;
8628         else
8629                 return generic_drop_inode(inode);
8630 }
8631
8632 static void init_once(void *foo)
8633 {
8634         struct btrfs_inode *ei = (struct btrfs_inode *) foo;
8635
8636         inode_init_once(&ei->vfs_inode);
8637 }
8638
8639 void btrfs_destroy_cachep(void)
8640 {
8641         /*
8642          * Make sure all delayed rcu free inodes are flushed before we
8643          * destroy cache.
8644          */
8645         rcu_barrier();
8646         if (btrfs_inode_cachep)
8647                 kmem_cache_destroy(btrfs_inode_cachep);
8648         if (btrfs_trans_handle_cachep)
8649                 kmem_cache_destroy(btrfs_trans_handle_cachep);
8650         if (btrfs_transaction_cachep)
8651                 kmem_cache_destroy(btrfs_transaction_cachep);
8652         if (btrfs_path_cachep)
8653                 kmem_cache_destroy(btrfs_path_cachep);
8654         if (btrfs_free_space_cachep)
8655                 kmem_cache_destroy(btrfs_free_space_cachep);
8656         if (btrfs_delalloc_work_cachep)
8657                 kmem_cache_destroy(btrfs_delalloc_work_cachep);
8658 }
8659
8660 int btrfs_init_cachep(void)
8661 {
8662         btrfs_inode_cachep = kmem_cache_create("btrfs_inode",
8663                         sizeof(struct btrfs_inode), 0,
8664                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, init_once);
8665         if (!btrfs_inode_cachep)
8666                 goto fail;
8667
8668         btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle",
8669                         sizeof(struct btrfs_trans_handle), 0,
8670                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8671         if (!btrfs_trans_handle_cachep)
8672                 goto fail;
8673
8674         btrfs_transaction_cachep = kmem_cache_create("btrfs_transaction",
8675                         sizeof(struct btrfs_transaction), 0,
8676                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8677         if (!btrfs_transaction_cachep)
8678                 goto fail;
8679
8680         btrfs_path_cachep = kmem_cache_create("btrfs_path",
8681                         sizeof(struct btrfs_path), 0,
8682                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8683         if (!btrfs_path_cachep)
8684                 goto fail;
8685
8686         btrfs_free_space_cachep = kmem_cache_create("btrfs_free_space",
8687                         sizeof(struct btrfs_free_space), 0,
8688                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8689         if (!btrfs_free_space_cachep)
8690                 goto fail;
8691
8692         btrfs_delalloc_work_cachep = kmem_cache_create("btrfs_delalloc_work",
8693                         sizeof(struct btrfs_delalloc_work), 0,
8694                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
8695                         NULL);
8696         if (!btrfs_delalloc_work_cachep)
8697                 goto fail;
8698
8699         return 0;
8700 fail:
8701         btrfs_destroy_cachep();
8702         return -ENOMEM;
8703 }
8704
8705 static int btrfs_getattr(struct vfsmount *mnt,
8706                          struct dentry *dentry, struct kstat *stat)
8707 {
8708         u64 delalloc_bytes;
8709         struct inode *inode = dentry->d_inode;
8710         u32 blocksize = inode->i_sb->s_blocksize;
8711
8712         generic_fillattr(inode, stat);
8713         stat->dev = BTRFS_I(inode)->root->anon_dev;
8714         stat->blksize = PAGE_CACHE_SIZE;
8715
8716         spin_lock(&BTRFS_I(inode)->lock);
8717         delalloc_bytes = BTRFS_I(inode)->delalloc_bytes;
8718         spin_unlock(&BTRFS_I(inode)->lock);
8719         stat->blocks = (ALIGN(inode_get_bytes(inode), blocksize) +
8720                         ALIGN(delalloc_bytes, blocksize)) >> 9;
8721         return 0;
8722 }
8723
8724 static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
8725                            struct inode *new_dir, struct dentry *new_dentry)
8726 {
8727         struct btrfs_trans_handle *trans;
8728         struct btrfs_root *root = BTRFS_I(old_dir)->root;
8729         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
8730         struct inode *new_inode = new_dentry->d_inode;
8731         struct inode *old_inode = old_dentry->d_inode;
8732         struct timespec ctime = CURRENT_TIME;
8733         u64 index = 0;
8734         u64 root_objectid;
8735         int ret;
8736         u64 old_ino = btrfs_ino(old_inode);
8737
8738         if (btrfs_ino(new_dir) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
8739                 return -EPERM;
8740
8741         /* we only allow rename subvolume link between subvolumes */
8742         if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
8743                 return -EXDEV;
8744
8745         if (old_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID ||
8746             (new_inode && btrfs_ino(new_inode) == BTRFS_FIRST_FREE_OBJECTID))
8747                 return -ENOTEMPTY;
8748
8749         if (S_ISDIR(old_inode->i_mode) && new_inode &&
8750             new_inode->i_size > BTRFS_EMPTY_DIR_SIZE)
8751                 return -ENOTEMPTY;
8752
8753
8754         /* check for collisions, even if the  name isn't there */
8755         ret = btrfs_check_dir_item_collision(dest, new_dir->i_ino,
8756                              new_dentry->d_name.name,
8757                              new_dentry->d_name.len);
8758
8759         if (ret) {
8760                 if (ret == -EEXIST) {
8761                         /* we shouldn't get
8762                          * eexist without a new_inode */
8763                         if (WARN_ON(!new_inode)) {
8764                                 return ret;
8765                         }
8766                 } else {
8767                         /* maybe -EOVERFLOW */
8768                         return ret;
8769                 }
8770         }
8771         ret = 0;
8772
8773         /*
8774          * we're using rename to replace one file with another.  Start IO on it
8775          * now so  we don't add too much work to the end of the transaction
8776          */
8777         if (new_inode && S_ISREG(old_inode->i_mode) && new_inode->i_size)
8778                 filemap_flush(old_inode->i_mapping);
8779
8780         /* close the racy window with snapshot create/destroy ioctl */
8781         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
8782                 down_read(&root->fs_info->subvol_sem);
8783         /*
8784          * We want to reserve the absolute worst case amount of items.  So if
8785          * both inodes are subvols and we need to unlink them then that would
8786          * require 4 item modifications, but if they are both normal inodes it
8787          * would require 5 item modifications, so we'll assume their normal
8788          * inodes.  So 5 * 2 is 10, plus 1 for the new link, so 11 total items
8789          * should cover the worst case number of items we'll modify.
8790          */
8791         trans = btrfs_start_transaction(root, 11);
8792         if (IS_ERR(trans)) {
8793                 ret = PTR_ERR(trans);
8794                 goto out_notrans;
8795         }
8796
8797         if (dest != root)
8798                 btrfs_record_root_in_trans(trans, dest);
8799
8800         ret = btrfs_set_inode_index(new_dir, &index);
8801         if (ret)
8802                 goto out_fail;
8803
8804         BTRFS_I(old_inode)->dir_index = 0ULL;
8805         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
8806                 /* force full log commit if subvolume involved. */
8807                 btrfs_set_log_full_commit(root->fs_info, trans);
8808         } else {
8809                 ret = btrfs_insert_inode_ref(trans, dest,
8810                                              new_dentry->d_name.name,
8811                                              new_dentry->d_name.len,
8812                                              old_ino,
8813                                              btrfs_ino(new_dir), index);
8814                 if (ret)
8815                         goto out_fail;
8816                 /*
8817                  * this is an ugly little race, but the rename is required
8818                  * to make sure that if we crash, the inode is either at the
8819                  * old name or the new one.  pinning the log transaction lets
8820                  * us make sure we don't allow a log commit to come in after
8821                  * we unlink the name but before we add the new name back in.
8822                  */
8823                 btrfs_pin_log_trans(root);
8824         }
8825
8826         inode_inc_iversion(old_dir);
8827         inode_inc_iversion(new_dir);
8828         inode_inc_iversion(old_inode);
8829         old_dir->i_ctime = old_dir->i_mtime = ctime;
8830         new_dir->i_ctime = new_dir->i_mtime = ctime;
8831         old_inode->i_ctime = ctime;
8832
8833         if (old_dentry->d_parent != new_dentry->d_parent)
8834                 btrfs_record_unlink_dir(trans, old_dir, old_inode, 1);
8835
8836         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
8837                 root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
8838                 ret = btrfs_unlink_subvol(trans, root, old_dir, root_objectid,
8839                                         old_dentry->d_name.name,
8840                                         old_dentry->d_name.len);
8841         } else {
8842                 ret = __btrfs_unlink_inode(trans, root, old_dir,
8843                                         old_dentry->d_inode,
8844                                         old_dentry->d_name.name,
8845                                         old_dentry->d_name.len);
8846                 if (!ret)
8847                         ret = btrfs_update_inode(trans, root, old_inode);
8848         }
8849         if (ret) {
8850                 btrfs_abort_transaction(trans, root, ret);
8851                 goto out_fail;
8852         }
8853
8854         if (new_inode) {
8855                 inode_inc_iversion(new_inode);
8856                 new_inode->i_ctime = CURRENT_TIME;
8857                 if (unlikely(btrfs_ino(new_inode) ==
8858                              BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
8859                         root_objectid = BTRFS_I(new_inode)->location.objectid;
8860                         ret = btrfs_unlink_subvol(trans, dest, new_dir,
8861                                                 root_objectid,
8862                                                 new_dentry->d_name.name,
8863                                                 new_dentry->d_name.len);
8864                         BUG_ON(new_inode->i_nlink == 0);
8865                 } else {
8866                         ret = btrfs_unlink_inode(trans, dest, new_dir,
8867                                                  new_dentry->d_inode,
8868                                                  new_dentry->d_name.name,
8869                                                  new_dentry->d_name.len);
8870                 }
8871                 if (!ret && new_inode->i_nlink == 0)
8872                         ret = btrfs_orphan_add(trans, new_dentry->d_inode);
8873                 if (ret) {
8874                         btrfs_abort_transaction(trans, root, ret);
8875                         goto out_fail;
8876                 }
8877         }
8878
8879         ret = btrfs_add_link(trans, new_dir, old_inode,
8880                              new_dentry->d_name.name,
8881                              new_dentry->d_name.len, 0, index);
8882         if (ret) {
8883                 btrfs_abort_transaction(trans, root, ret);
8884                 goto out_fail;
8885         }
8886
8887         if (old_inode->i_nlink == 1)
8888                 BTRFS_I(old_inode)->dir_index = index;
8889
8890         if (old_ino != BTRFS_FIRST_FREE_OBJECTID) {
8891                 struct dentry *parent = new_dentry->d_parent;
8892                 btrfs_log_new_name(trans, old_inode, old_dir, parent);
8893                 btrfs_end_log_trans(root);
8894         }
8895 out_fail:
8896         btrfs_end_transaction(trans, root);
8897 out_notrans:
8898         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
8899                 up_read(&root->fs_info->subvol_sem);
8900
8901         return ret;
8902 }
8903
8904 static int btrfs_rename2(struct inode *old_dir, struct dentry *old_dentry,
8905                          struct inode *new_dir, struct dentry *new_dentry,
8906                          unsigned int flags)
8907 {
8908         if (flags & ~RENAME_NOREPLACE)
8909                 return -EINVAL;
8910
8911         return btrfs_rename(old_dir, old_dentry, new_dir, new_dentry);
8912 }
8913
8914 static void btrfs_run_delalloc_work(struct btrfs_work *work)
8915 {
8916         struct btrfs_delalloc_work *delalloc_work;
8917         struct inode *inode;
8918
8919         delalloc_work = container_of(work, struct btrfs_delalloc_work,
8920                                      work);
8921         inode = delalloc_work->inode;
8922         if (delalloc_work->wait) {
8923                 btrfs_wait_ordered_range(inode, 0, (u64)-1);
8924         } else {
8925                 filemap_flush(inode->i_mapping);
8926                 if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
8927                              &BTRFS_I(inode)->runtime_flags))
8928                         filemap_flush(inode->i_mapping);
8929         }
8930
8931         if (delalloc_work->delay_iput)
8932                 btrfs_add_delayed_iput(inode);
8933         else
8934                 iput(inode);
8935         complete(&delalloc_work->completion);
8936 }
8937
8938 struct btrfs_delalloc_work *btrfs_alloc_delalloc_work(struct inode *inode,
8939                                                     int wait, int delay_iput)
8940 {
8941         struct btrfs_delalloc_work *work;
8942
8943         work = kmem_cache_zalloc(btrfs_delalloc_work_cachep, GFP_NOFS);
8944         if (!work)
8945                 return NULL;
8946
8947         init_completion(&work->completion);
8948         INIT_LIST_HEAD(&work->list);
8949         work->inode = inode;
8950         work->wait = wait;
8951         work->delay_iput = delay_iput;
8952         WARN_ON_ONCE(!inode);
8953         btrfs_init_work(&work->work, btrfs_flush_delalloc_helper,
8954                         btrfs_run_delalloc_work, NULL, NULL);
8955
8956         return work;
8957 }
8958
8959 void btrfs_wait_and_free_delalloc_work(struct btrfs_delalloc_work *work)
8960 {
8961         wait_for_completion(&work->completion);
8962         kmem_cache_free(btrfs_delalloc_work_cachep, work);
8963 }
8964
8965 /*
8966  * some fairly slow code that needs optimization. This walks the list
8967  * of all the inodes with pending delalloc and forces them to disk.
8968  */
8969 static int __start_delalloc_inodes(struct btrfs_root *root, int delay_iput,
8970                                    int nr)
8971 {
8972         struct btrfs_inode *binode;
8973         struct inode *inode;
8974         struct btrfs_delalloc_work *work, *next;
8975         struct list_head works;
8976         struct list_head splice;
8977         int ret = 0;
8978
8979         INIT_LIST_HEAD(&works);
8980         INIT_LIST_HEAD(&splice);
8981
8982         mutex_lock(&root->delalloc_mutex);
8983         spin_lock(&root->delalloc_lock);
8984         list_splice_init(&root->delalloc_inodes, &splice);
8985         while (!list_empty(&splice)) {
8986                 binode = list_entry(splice.next, struct btrfs_inode,
8987                                     delalloc_inodes);
8988
8989                 list_move_tail(&binode->delalloc_inodes,
8990                                &root->delalloc_inodes);
8991                 inode = igrab(&binode->vfs_inode);
8992                 if (!inode) {
8993                         cond_resched_lock(&root->delalloc_lock);
8994                         continue;
8995                 }
8996                 spin_unlock(&root->delalloc_lock);
8997
8998                 work = btrfs_alloc_delalloc_work(inode, 0, delay_iput);
8999                 if (!work) {
9000                         if (delay_iput)
9001                                 btrfs_add_delayed_iput(inode);
9002                         else
9003                                 iput(inode);
9004                         ret = -ENOMEM;
9005                         goto out;
9006                 }
9007                 list_add_tail(&work->list, &works);
9008                 btrfs_queue_work(root->fs_info->flush_workers,
9009                                  &work->work);
9010                 ret++;
9011                 if (nr != -1 && ret >= nr)
9012                         goto out;
9013                 cond_resched();
9014                 spin_lock(&root->delalloc_lock);
9015         }
9016         spin_unlock(&root->delalloc_lock);
9017
9018 out:
9019         list_for_each_entry_safe(work, next, &works, list) {
9020                 list_del_init(&work->list);
9021                 btrfs_wait_and_free_delalloc_work(work);
9022         }
9023
9024         if (!list_empty_careful(&splice)) {
9025                 spin_lock(&root->delalloc_lock);
9026                 list_splice_tail(&splice, &root->delalloc_inodes);
9027                 spin_unlock(&root->delalloc_lock);
9028         }
9029         mutex_unlock(&root->delalloc_mutex);
9030         return ret;
9031 }
9032
9033 int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
9034 {
9035         int ret;
9036
9037         if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
9038                 return -EROFS;
9039
9040         ret = __start_delalloc_inodes(root, delay_iput, -1);
9041         if (ret > 0)
9042                 ret = 0;
9043         /*
9044          * the filemap_flush will queue IO into the worker threads, but
9045          * we have to make sure the IO is actually started and that
9046          * ordered extents get created before we return
9047          */
9048         atomic_inc(&root->fs_info->async_submit_draining);
9049         while (atomic_read(&root->fs_info->nr_async_submits) ||
9050               atomic_read(&root->fs_info->async_delalloc_pages)) {
9051                 wait_event(root->fs_info->async_submit_wait,
9052                    (atomic_read(&root->fs_info->nr_async_submits) == 0 &&
9053                     atomic_read(&root->fs_info->async_delalloc_pages) == 0));
9054         }
9055         atomic_dec(&root->fs_info->async_submit_draining);
9056         return ret;
9057 }
9058
9059 int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int delay_iput,
9060                                int nr)
9061 {
9062         struct btrfs_root *root;
9063         struct list_head splice;
9064         int ret;
9065
9066         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
9067                 return -EROFS;
9068
9069         INIT_LIST_HEAD(&splice);
9070
9071         mutex_lock(&fs_info->delalloc_root_mutex);
9072         spin_lock(&fs_info->delalloc_root_lock);
9073         list_splice_init(&fs_info->delalloc_roots, &splice);
9074         while (!list_empty(&splice) && nr) {
9075                 root = list_first_entry(&splice, struct btrfs_root,
9076                                         delalloc_root);
9077                 root = btrfs_grab_fs_root(root);
9078                 BUG_ON(!root);
9079                 list_move_tail(&root->delalloc_root,
9080                                &fs_info->delalloc_roots);
9081                 spin_unlock(&fs_info->delalloc_root_lock);
9082
9083                 ret = __start_delalloc_inodes(root, delay_iput, nr);
9084                 btrfs_put_fs_root(root);
9085                 if (ret < 0)
9086                         goto out;
9087
9088                 if (nr != -1) {
9089                         nr -= ret;
9090                         WARN_ON(nr < 0);
9091                 }
9092                 spin_lock(&fs_info->delalloc_root_lock);
9093         }
9094         spin_unlock(&fs_info->delalloc_root_lock);
9095
9096         ret = 0;
9097         atomic_inc(&fs_info->async_submit_draining);
9098         while (atomic_read(&fs_info->nr_async_submits) ||
9099               atomic_read(&fs_info->async_delalloc_pages)) {
9100                 wait_event(fs_info->async_submit_wait,
9101                    (atomic_read(&fs_info->nr_async_submits) == 0 &&
9102                     atomic_read(&fs_info->async_delalloc_pages) == 0));
9103         }
9104         atomic_dec(&fs_info->async_submit_draining);
9105 out:
9106         if (!list_empty_careful(&splice)) {
9107                 spin_lock(&fs_info->delalloc_root_lock);
9108                 list_splice_tail(&splice, &fs_info->delalloc_roots);
9109                 spin_unlock(&fs_info->delalloc_root_lock);
9110         }
9111         mutex_unlock(&fs_info->delalloc_root_mutex);
9112         return ret;
9113 }
9114
9115 static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
9116                          const char *symname)
9117 {
9118         struct btrfs_trans_handle *trans;
9119         struct btrfs_root *root = BTRFS_I(dir)->root;
9120         struct btrfs_path *path;
9121         struct btrfs_key key;
9122         struct inode *inode = NULL;
9123         int err;
9124         int drop_inode = 0;
9125         u64 objectid;
9126         u64 index = 0;
9127         int name_len;
9128         int datasize;
9129         unsigned long ptr;
9130         struct btrfs_file_extent_item *ei;
9131         struct extent_buffer *leaf;
9132
9133         name_len = strlen(symname);
9134         if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(root))
9135                 return -ENAMETOOLONG;
9136
9137         /*
9138          * 2 items for inode item and ref
9139          * 2 items for dir items
9140          * 1 item for xattr if selinux is on
9141          */
9142         trans = btrfs_start_transaction(root, 5);
9143         if (IS_ERR(trans))
9144                 return PTR_ERR(trans);
9145
9146         err = btrfs_find_free_ino(root, &objectid);
9147         if (err)
9148                 goto out_unlock;
9149
9150         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
9151                                 dentry->d_name.len, btrfs_ino(dir), objectid,
9152                                 S_IFLNK|S_IRWXUGO, &index);
9153         if (IS_ERR(inode)) {
9154                 err = PTR_ERR(inode);
9155                 goto out_unlock;
9156         }
9157
9158         /*
9159         * If the active LSM wants to access the inode during
9160         * d_instantiate it needs these. Smack checks to see
9161         * if the filesystem supports xattrs by looking at the
9162         * ops vector.
9163         */
9164         inode->i_fop = &btrfs_file_operations;
9165         inode->i_op = &btrfs_file_inode_operations;
9166         inode->i_mapping->a_ops = &btrfs_aops;
9167         inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
9168         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
9169
9170         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
9171         if (err)
9172                 goto out_unlock_inode;
9173
9174         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
9175         if (err)
9176                 goto out_unlock_inode;
9177
9178         path = btrfs_alloc_path();
9179         if (!path) {
9180                 err = -ENOMEM;
9181                 goto out_unlock_inode;
9182         }
9183         key.objectid = btrfs_ino(inode);
9184         key.offset = 0;
9185         key.type = BTRFS_EXTENT_DATA_KEY;
9186         datasize = btrfs_file_extent_calc_inline_size(name_len);
9187         err = btrfs_insert_empty_item(trans, root, path, &key,
9188                                       datasize);
9189         if (err) {
9190                 btrfs_free_path(path);
9191                 goto out_unlock_inode;
9192         }
9193         leaf = path->nodes[0];
9194         ei = btrfs_item_ptr(leaf, path->slots[0],
9195                             struct btrfs_file_extent_item);
9196         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
9197         btrfs_set_file_extent_type(leaf, ei,
9198                                    BTRFS_FILE_EXTENT_INLINE);
9199         btrfs_set_file_extent_encryption(leaf, ei, 0);
9200         btrfs_set_file_extent_compression(leaf, ei, 0);
9201         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
9202         btrfs_set_file_extent_ram_bytes(leaf, ei, name_len);
9203
9204         ptr = btrfs_file_extent_inline_start(ei);
9205         write_extent_buffer(leaf, symname, ptr, name_len);
9206         btrfs_mark_buffer_dirty(leaf);
9207         btrfs_free_path(path);
9208
9209         inode->i_op = &btrfs_symlink_inode_operations;
9210         inode->i_mapping->a_ops = &btrfs_symlink_aops;
9211         inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
9212         inode_set_bytes(inode, name_len);
9213         btrfs_i_size_write(inode, name_len);
9214         err = btrfs_update_inode(trans, root, inode);
9215         if (err) {
9216                 drop_inode = 1;
9217                 goto out_unlock_inode;
9218         }
9219
9220         unlock_new_inode(inode);
9221         d_instantiate(dentry, inode);
9222
9223 out_unlock:
9224         btrfs_end_transaction(trans, root);
9225         if (drop_inode) {
9226                 inode_dec_link_count(inode);
9227                 iput(inode);
9228         }
9229         btrfs_btree_balance_dirty(root);
9230         return err;
9231
9232 out_unlock_inode:
9233         drop_inode = 1;
9234         unlock_new_inode(inode);
9235         goto out_unlock;
9236 }
9237
9238 static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
9239                                        u64 start, u64 num_bytes, u64 min_size,
9240                                        loff_t actual_len, u64 *alloc_hint,
9241                                        struct btrfs_trans_handle *trans)
9242 {
9243         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
9244         struct extent_map *em;
9245         struct btrfs_root *root = BTRFS_I(inode)->root;
9246         struct btrfs_key ins;
9247         u64 cur_offset = start;
9248         u64 i_size;
9249         u64 cur_bytes;
9250         int ret = 0;
9251         bool own_trans = true;
9252
9253         if (trans)
9254                 own_trans = false;
9255         while (num_bytes > 0) {
9256                 if (own_trans) {
9257                         trans = btrfs_start_transaction(root, 3);
9258                         if (IS_ERR(trans)) {
9259                                 ret = PTR_ERR(trans);
9260                                 break;
9261                         }
9262                 }
9263
9264                 cur_bytes = min(num_bytes, 256ULL * 1024 * 1024);
9265                 cur_bytes = max(cur_bytes, min_size);
9266                 ret = btrfs_reserve_extent(root, cur_bytes, min_size, 0,
9267                                            *alloc_hint, &ins, 1, 0);
9268                 if (ret) {
9269                         if (own_trans)
9270                                 btrfs_end_transaction(trans, root);
9271                         break;
9272                 }
9273
9274                 ret = insert_reserved_file_extent(trans, inode,
9275                                                   cur_offset, ins.objectid,
9276                                                   ins.offset, ins.offset,
9277                                                   ins.offset, 0, 0, 0,
9278                                                   BTRFS_FILE_EXTENT_PREALLOC);
9279                 if (ret) {
9280                         btrfs_free_reserved_extent(root, ins.objectid,
9281                                                    ins.offset, 0);
9282                         btrfs_abort_transaction(trans, root, ret);
9283                         if (own_trans)
9284                                 btrfs_end_transaction(trans, root);
9285                         break;
9286                 }
9287                 btrfs_drop_extent_cache(inode, cur_offset,
9288                                         cur_offset + ins.offset -1, 0);
9289
9290                 em = alloc_extent_map();
9291                 if (!em) {
9292                         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
9293                                 &BTRFS_I(inode)->runtime_flags);
9294                         goto next;
9295                 }
9296
9297                 em->start = cur_offset;
9298                 em->orig_start = cur_offset;
9299                 em->len = ins.offset;
9300                 em->block_start = ins.objectid;
9301                 em->block_len = ins.offset;
9302                 em->orig_block_len = ins.offset;
9303                 em->ram_bytes = ins.offset;
9304                 em->bdev = root->fs_info->fs_devices->latest_bdev;
9305                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
9306                 em->generation = trans->transid;
9307
9308                 while (1) {
9309                         write_lock(&em_tree->lock);
9310                         ret = add_extent_mapping(em_tree, em, 1);
9311                         write_unlock(&em_tree->lock);
9312                         if (ret != -EEXIST)
9313                                 break;
9314                         btrfs_drop_extent_cache(inode, cur_offset,
9315                                                 cur_offset + ins.offset - 1,
9316                                                 0);
9317                 }
9318                 free_extent_map(em);
9319 next:
9320                 num_bytes -= ins.offset;
9321                 cur_offset += ins.offset;
9322                 *alloc_hint = ins.objectid + ins.offset;
9323
9324                 inode_inc_iversion(inode);
9325                 inode->i_ctime = CURRENT_TIME;
9326                 BTRFS_I(inode)->flags |= BTRFS_INODE_PREALLOC;
9327                 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
9328                     (actual_len > inode->i_size) &&
9329                     (cur_offset > inode->i_size)) {
9330                         if (cur_offset > actual_len)
9331                                 i_size = actual_len;
9332                         else
9333                                 i_size = cur_offset;
9334                         i_size_write(inode, i_size);
9335                         btrfs_ordered_update_i_size(inode, i_size, NULL);
9336                 }
9337
9338                 ret = btrfs_update_inode(trans, root, inode);
9339
9340                 if (ret) {
9341                         btrfs_abort_transaction(trans, root, ret);
9342                         if (own_trans)
9343                                 btrfs_end_transaction(trans, root);
9344                         break;
9345                 }
9346
9347                 if (own_trans)
9348                         btrfs_end_transaction(trans, root);
9349         }
9350         return ret;
9351 }
9352
9353 int btrfs_prealloc_file_range(struct inode *inode, int mode,
9354                               u64 start, u64 num_bytes, u64 min_size,
9355                               loff_t actual_len, u64 *alloc_hint)
9356 {
9357         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
9358                                            min_size, actual_len, alloc_hint,
9359                                            NULL);
9360 }
9361
9362 int btrfs_prealloc_file_range_trans(struct inode *inode,
9363                                     struct btrfs_trans_handle *trans, int mode,
9364                                     u64 start, u64 num_bytes, u64 min_size,
9365                                     loff_t actual_len, u64 *alloc_hint)
9366 {
9367         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
9368                                            min_size, actual_len, alloc_hint, trans);
9369 }
9370
9371 static int btrfs_set_page_dirty(struct page *page)
9372 {
9373         return __set_page_dirty_nobuffers(page);
9374 }
9375
9376 static int btrfs_permission(struct inode *inode, int mask)
9377 {
9378         struct btrfs_root *root = BTRFS_I(inode)->root;
9379         umode_t mode = inode->i_mode;
9380
9381         if (mask & MAY_WRITE &&
9382             (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) {
9383                 if (btrfs_root_readonly(root))
9384                         return -EROFS;
9385                 if (BTRFS_I(inode)->flags & BTRFS_INODE_READONLY)
9386                         return -EACCES;
9387         }
9388         return generic_permission(inode, mask);
9389 }
9390
9391 static int btrfs_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
9392 {
9393         struct btrfs_trans_handle *trans;
9394         struct btrfs_root *root = BTRFS_I(dir)->root;
9395         struct inode *inode = NULL;
9396         u64 objectid;
9397         u64 index;
9398         int ret = 0;
9399
9400         /*
9401          * 5 units required for adding orphan entry
9402          */
9403         trans = btrfs_start_transaction(root, 5);
9404         if (IS_ERR(trans))
9405                 return PTR_ERR(trans);
9406
9407         ret = btrfs_find_free_ino(root, &objectid);
9408         if (ret)
9409                 goto out;
9410
9411         inode = btrfs_new_inode(trans, root, dir, NULL, 0,
9412                                 btrfs_ino(dir), objectid, mode, &index);
9413         if (IS_ERR(inode)) {
9414                 ret = PTR_ERR(inode);
9415                 inode = NULL;
9416                 goto out;
9417         }
9418
9419         inode->i_fop = &btrfs_file_operations;
9420         inode->i_op = &btrfs_file_inode_operations;
9421
9422         inode->i_mapping->a_ops = &btrfs_aops;
9423         inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
9424         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
9425
9426         ret = btrfs_init_inode_security(trans, inode, dir, NULL);
9427         if (ret)
9428                 goto out_inode;
9429
9430         ret = btrfs_update_inode(trans, root, inode);
9431         if (ret)
9432                 goto out_inode;
9433         ret = btrfs_orphan_add(trans, inode);
9434         if (ret)
9435                 goto out_inode;
9436
9437         /*
9438          * We set number of links to 0 in btrfs_new_inode(), and here we set
9439          * it to 1 because d_tmpfile() will issue a warning if the count is 0,
9440          * through:
9441          *
9442          *    d_tmpfile() -> inode_dec_link_count() -> drop_nlink()
9443          */
9444         set_nlink(inode, 1);
9445         unlock_new_inode(inode);
9446         d_tmpfile(dentry, inode);
9447         mark_inode_dirty(inode);
9448
9449 out:
9450         btrfs_end_transaction(trans, root);
9451         if (ret)
9452                 iput(inode);
9453         btrfs_balance_delayed_items(root);
9454         btrfs_btree_balance_dirty(root);
9455         return ret;
9456
9457 out_inode:
9458         unlock_new_inode(inode);
9459         goto out;
9460
9461 }
9462
9463 static const struct inode_operations btrfs_dir_inode_operations = {
9464         .getattr        = btrfs_getattr,
9465         .lookup         = btrfs_lookup,
9466         .create         = btrfs_create,
9467         .unlink         = btrfs_unlink,
9468         .link           = btrfs_link,
9469         .mkdir          = btrfs_mkdir,
9470         .rmdir          = btrfs_rmdir,
9471         .rename2        = btrfs_rename2,
9472         .symlink        = btrfs_symlink,
9473         .setattr        = btrfs_setattr,
9474         .mknod          = btrfs_mknod,
9475         .setxattr       = btrfs_setxattr,
9476         .getxattr       = btrfs_getxattr,
9477         .listxattr      = btrfs_listxattr,
9478         .removexattr    = btrfs_removexattr,
9479         .permission     = btrfs_permission,
9480         .get_acl        = btrfs_get_acl,
9481         .set_acl        = btrfs_set_acl,
9482         .update_time    = btrfs_update_time,
9483         .tmpfile        = btrfs_tmpfile,
9484 };
9485 static const struct inode_operations btrfs_dir_ro_inode_operations = {
9486         .lookup         = btrfs_lookup,
9487         .permission     = btrfs_permission,
9488         .get_acl        = btrfs_get_acl,
9489         .set_acl        = btrfs_set_acl,
9490         .update_time    = btrfs_update_time,
9491 };
9492
9493 static const struct file_operations btrfs_dir_file_operations = {
9494         .llseek         = generic_file_llseek,
9495         .read           = generic_read_dir,
9496         .iterate        = btrfs_real_readdir,
9497         .unlocked_ioctl = btrfs_ioctl,
9498 #ifdef CONFIG_COMPAT
9499         .compat_ioctl   = btrfs_ioctl,
9500 #endif
9501         .release        = btrfs_release_file,
9502         .fsync          = btrfs_sync_file,
9503 };
9504
9505 static struct extent_io_ops btrfs_extent_io_ops = {
9506         .fill_delalloc = run_delalloc_range,
9507         .submit_bio_hook = btrfs_submit_bio_hook,
9508         .merge_bio_hook = btrfs_merge_bio_hook,
9509         .readpage_end_io_hook = btrfs_readpage_end_io_hook,
9510         .writepage_end_io_hook = btrfs_writepage_end_io_hook,
9511         .writepage_start_hook = btrfs_writepage_start_hook,
9512         .set_bit_hook = btrfs_set_bit_hook,
9513         .clear_bit_hook = btrfs_clear_bit_hook,
9514         .merge_extent_hook = btrfs_merge_extent_hook,
9515         .split_extent_hook = btrfs_split_extent_hook,
9516 };
9517
9518 /*
9519  * btrfs doesn't support the bmap operation because swapfiles
9520  * use bmap to make a mapping of extents in the file.  They assume
9521  * these extents won't change over the life of the file and they
9522  * use the bmap result to do IO directly to the drive.
9523  *
9524  * the btrfs bmap call would return logical addresses that aren't
9525  * suitable for IO and they also will change frequently as COW
9526  * operations happen.  So, swapfile + btrfs == corruption.
9527  *
9528  * For now we're avoiding this by dropping bmap.
9529  */
9530 static const struct address_space_operations btrfs_aops = {
9531         .readpage       = btrfs_readpage,
9532         .writepage      = btrfs_writepage,
9533         .writepages     = btrfs_writepages,
9534         .readpages      = btrfs_readpages,
9535         .direct_IO      = btrfs_direct_IO,
9536         .invalidatepage = btrfs_invalidatepage,
9537         .releasepage    = btrfs_releasepage,
9538         .set_page_dirty = btrfs_set_page_dirty,
9539         .error_remove_page = generic_error_remove_page,
9540 };
9541
9542 static const struct address_space_operations btrfs_symlink_aops = {
9543         .readpage       = btrfs_readpage,
9544         .writepage      = btrfs_writepage,
9545         .invalidatepage = btrfs_invalidatepage,
9546         .releasepage    = btrfs_releasepage,
9547 };
9548
9549 static const struct inode_operations btrfs_file_inode_operations = {
9550         .getattr        = btrfs_getattr,
9551         .setattr        = btrfs_setattr,
9552         .setxattr       = btrfs_setxattr,
9553         .getxattr       = btrfs_getxattr,
9554         .listxattr      = btrfs_listxattr,
9555         .removexattr    = btrfs_removexattr,
9556         .permission     = btrfs_permission,
9557         .fiemap         = btrfs_fiemap,
9558         .get_acl        = btrfs_get_acl,
9559         .set_acl        = btrfs_set_acl,
9560         .update_time    = btrfs_update_time,
9561 };
9562 static const struct inode_operations btrfs_special_inode_operations = {
9563         .getattr        = btrfs_getattr,
9564         .setattr        = btrfs_setattr,
9565         .permission     = btrfs_permission,
9566         .setxattr       = btrfs_setxattr,
9567         .getxattr       = btrfs_getxattr,
9568         .listxattr      = btrfs_listxattr,
9569         .removexattr    = btrfs_removexattr,
9570         .get_acl        = btrfs_get_acl,
9571         .set_acl        = btrfs_set_acl,
9572         .update_time    = btrfs_update_time,
9573 };
9574 static const struct inode_operations btrfs_symlink_inode_operations = {
9575         .readlink       = generic_readlink,
9576         .follow_link    = page_follow_link_light,
9577         .put_link       = page_put_link,
9578         .getattr        = btrfs_getattr,
9579         .setattr        = btrfs_setattr,
9580         .permission     = btrfs_permission,
9581         .setxattr       = btrfs_setxattr,
9582         .getxattr       = btrfs_getxattr,
9583         .listxattr      = btrfs_listxattr,
9584         .removexattr    = btrfs_removexattr,
9585         .update_time    = btrfs_update_time,
9586 };
9587
9588 const struct dentry_operations btrfs_dentry_operations = {
9589         .d_delete       = btrfs_dentry_delete,
9590         .d_release      = btrfs_dentry_release,
9591 };