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