drivers/md/bitmap.c

   1 /*
   2  * bitmap.c two-level bitmap (C) Peter T. Breuer (ptb@ot.uc3m.es) 2003
   3  *
   4  * bitmap_create  - sets up the bitmap structure
   5  * bitmap_destroy - destroys the bitmap structure
   6  *
   7  * additions, Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.:
   8  * - added disk storage for bitmap
   9  * - changes to allow various bitmap chunk sizes
  10  */
  11
  12 /*
  13  * Still to do:
  14  *
  15  * flush after percent set rather than just time based. (maybe both).
  16  */
  17
  18 #include <linux/blkdev.h>
  19 #include <linux/module.h>
  20 #include <linux/errno.h>
  21 #include <linux/slab.h>
  22 #include <linux/init.h>
  23 #include <linux/timer.h>
  24 #include <linux/sched.h>
  25 #include <linux/list.h>
  26 #include <linux/file.h>
  27 #include <linux/mount.h>
  28 #include <linux/buffer_head.h>
  29 #include <linux/seq_file.h>
  30 #include <trace/events/block.h>
  31 #include "md.h"
  32 #include "bitmap.h"
  33
  34 static inline char *bmname(struct bitmap *bitmap)
  35 {
  36         return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
  37 }
  38
  39 /*
  40  * check a page and, if necessary, allocate it (or hijack it if the alloc fails)
  41  *
  42  * 1) check to see if this page is allocated, if it's not then try to alloc
  43  * 2) if the alloc fails, set the page's hijacked flag so we'll use the
  44  *    page pointer directly as a counter
  45  *
  46  * if we find our page, we increment the page's refcount so that it stays
  47  * allocated while we're using it
  48  */
  49 static int bitmap_checkpage(struct bitmap_counts *bitmap,
  50                             unsigned long page, int create, int no_hijack)
  51 __releases(bitmap->lock)
  52 __acquires(bitmap->lock)
  53 {
  54         unsigned char *mappage;
  55
  56         if (page >= bitmap->pages) {
  57                 /* This can happen if bitmap_start_sync goes beyond
  58                  * End-of-device while looking for a whole page.
  59                  * It is harmless.
  60                  */
  61                 return -EINVAL;
  62         }
  63
  64         if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
  65                 return 0;
  66
  67         if (bitmap->bp[page].map) /* page is already allocated, just return */
  68                 return 0;
  69
  70         if (!create)
  71                 return -ENOENT;
  72
  73         /* this page has not been allocated yet */
  74
  75         spin_unlock_irq(&bitmap->lock);
  76         /* It is possible that this is being called inside a
  77          * prepare_to_wait/finish_wait loop from raid5c:make_request().
  78          * In general it is not permitted to sleep in that context as it
  79          * can cause the loop to spin freely.
  80          * That doesn't apply here as we can only reach this point
  81          * once with any loop.
  82          * When this function completes, either bp[page].map or
  83          * bp[page].hijacked.  In either case, this function will
  84          * abort before getting to this point again.  So there is
  85          * no risk of a free-spin, and so it is safe to assert
  86          * that sleeping here is allowed.
  87          */
  88         sched_annotate_sleep();
  89         mappage = kzalloc(PAGE_SIZE, GFP_NOIO);
  90         spin_lock_irq(&bitmap->lock);
  91
  92         if (mappage == NULL) {
  93                 pr_debug("md/bitmap: map page allocation failed, hijacking\n");
  94                 /* We don't support hijack for cluster raid */
  95                 if (no_hijack)
  96                         return -ENOMEM;
  97                 /* failed - set the hijacked flag so that we can use the
  98                  * pointer as a counter */
  99                 if (!bitmap->bp[page].map)
 100                         bitmap->bp[page].hijacked = 1;
 101         } else if (bitmap->bp[page].map ||
 102                    bitmap->bp[page].hijacked) {
 103                 /* somebody beat us to getting the page */
 104                 kfree(mappage);
 105         } else {
 106
 107                 /* no page was in place and we have one, so install it */
 108
 109                 bitmap->bp[page].map = mappage;
 110                 bitmap->missing_pages--;
 111         }
 112         return 0;
 113 }
 114
 115 /* if page is completely empty, put it back on the free list, or dealloc it */
 116 /* if page was hijacked, unmark the flag so it might get alloced next time */
 117 /* Note: lock should be held when calling this */
 118 static void bitmap_checkfree(struct bitmap_counts *bitmap, unsigned long page)
 119 {
 120         char *ptr;
 121
 122         if (bitmap->bp[page].count) /* page is still busy */
 123                 return;
 124
 125         /* page is no longer in use, it can be released */
 126
 127         if (bitmap->bp[page].hijacked) { /* page was hijacked, undo this now */
 128                 bitmap->bp[page].hijacked = 0;
 129                 bitmap->bp[page].map = NULL;
 130         } else {
 131                 /* normal case, free the page */
 132                 ptr = bitmap->bp[page].map;
 133                 bitmap->bp[page].map = NULL;
 134                 bitmap->missing_pages++;
 135                 kfree(ptr);
 136         }
 137 }
 138
 139 /*
 140  * bitmap file handling - read and write the bitmap file and its superblock
 141  */
 142
 143 /*
 144  * basic page I/O operations
 145  */
 146
 147 /* IO operations when bitmap is stored near all superblocks */
 148 static int read_sb_page(struct mddev *mddev, loff_t offset,
 149                         struct page *page,
 150                         unsigned long index, int size)
 151 {
 152         /* choose a good rdev and read the page from there */
 153
 154         struct md_rdev *rdev;
 155         sector_t target;
 156
 157         rdev_for_each(rdev, mddev) {
 158                 if (! test_bit(In_sync, &rdev->flags)
 159                     || test_bit(Faulty, &rdev->flags)
 160                     || test_bit(Bitmap_sync, &rdev->flags))
 161                         continue;
 162
 163                 target = offset + index * (PAGE_SIZE/512);
 164
 165                 if (sync_page_io(rdev, target,
 166                                  roundup(size, bdev_logical_block_size(rdev->bdev)),
 167                                  page, REQ_OP_READ, 0, true)) {
 168                         page->index = index;
 169                         return 0;
 170                 }
 171         }
 172         return -EIO;
 173 }
 174
 175 static struct md_rdev *next_active_rdev(struct md_rdev *rdev, struct mddev *mddev)
 176 {
 177         /* Iterate the disks of an mddev, using rcu to protect access to the
 178          * linked list, and raising the refcount of devices we return to ensure
 179          * they don't disappear while in use.
 180          * As devices are only added or removed when raid_disk is < 0 and
 181          * nr_pending is 0 and In_sync is clear, the entries we return will
 182          * still be in the same position on the list when we re-enter
 183          * list_for_each_entry_continue_rcu.
 184          *
 185          * Note that if entered with 'rdev == NULL' to start at the
 186          * beginning, we temporarily assign 'rdev' to an address which
 187          * isn't really an rdev, but which can be used by
 188          * list_for_each_entry_continue_rcu() to find the first entry.
 189          */
 190         rcu_read_lock();
 191         if (rdev == NULL)
 192                 /* start at the beginning */
 193                 rdev = list_entry(&mddev->disks, struct md_rdev, same_set);
 194         else {
 195                 /* release the previous rdev and start from there. */
 196                 rdev_dec_pending(rdev, mddev);
 197         }
 198         list_for_each_entry_continue_rcu(rdev, &mddev->disks, same_set) {
 199                 if (rdev->raid_disk >= 0 &&
 200                     !test_bit(Faulty, &rdev->flags)) {
 201                         /* this is a usable devices */
 202                         atomic_inc(&rdev->nr_pending);
 203                         rcu_read_unlock();
 204                         return rdev;
 205                 }
 206         }
 207         rcu_read_unlock();
 208         return NULL;
 209 }
 210
 211 static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
 212 {
 213         struct md_rdev *rdev;
 214         struct block_device *bdev;
 215         struct mddev *mddev = bitmap->mddev;
 216         struct bitmap_storage *store = &bitmap->storage;
 217
 218 restart:
 219         rdev = NULL;
 220         while ((rdev = next_active_rdev(rdev, mddev)) != NULL) {
 221                 int size = PAGE_SIZE;
 222                 loff_t offset = mddev->bitmap_info.offset;
 223
 224                 bdev = (rdev->meta_bdev) ? rdev->meta_bdev : rdev->bdev;
 225
 226                 if (page->index == store->file_pages-1) {
 227                         int last_page_size = store->bytes & (PAGE_SIZE-1);
 228                         if (last_page_size == 0)
 229                                 last_page_size = PAGE_SIZE;
 230                         size = roundup(last_page_size,
 231                                        bdev_logical_block_size(bdev));
 232                 }
 233                 /* Just make sure we aren't corrupting data or
 234                  * metadata
 235                  */
 236                 if (mddev->external) {
 237                         /* Bitmap could be anywhere. */
 238                         if (rdev->sb_start + offset + (page->index
 239                                                        * (PAGE_SIZE/512))
 240                             > rdev->data_offset
 241                             &&
 242                             rdev->sb_start + offset
 243                             < (rdev->data_offset + mddev->dev_sectors
 244                              + (PAGE_SIZE/512)))
 245                                 goto bad_alignment;
 246                 } else if (offset < 0) {
 247                         /* DATA  BITMAP METADATA  */
 248                         if (offset
 249                             + (long)(page->index * (PAGE_SIZE/512))
 250                             + size/512 > 0)
 251                                 /* bitmap runs in to metadata */
 252                                 goto bad_alignment;
 253                         if (rdev->data_offset + mddev->dev_sectors
 254                             > rdev->sb_start + offset)
 255                                 /* data runs in to bitmap */
 256                                 goto bad_alignment;
 257                 } else if (rdev->sb_start < rdev->data_offset) {
 258                         /* METADATA BITMAP DATA */
 259                         if (rdev->sb_start
 260                             + offset
 261                             + page->index*(PAGE_SIZE/512) + size/512
 262                             > rdev->data_offset)
 263                                 /* bitmap runs in to data */
 264                                 goto bad_alignment;
 265                 } else {
 266                         /* DATA METADATA BITMAP - no problems */
 267                 }
 268                 md_super_write(mddev, rdev,
 269                                rdev->sb_start + offset
 270                                + page->index * (PAGE_SIZE/512),
 271                                size,
 272                                page);
 273         }
 274
 275         if (wait && md_super_wait(mddev) < 0)
 276                 goto restart;
 277         return 0;
 278
 279  bad_alignment:
 280         return -EINVAL;
 281 }
 282
 283 static void bitmap_file_kick(struct bitmap *bitmap);
 284 /*
 285  * write out a page to a file
 286  */
 287 static void write_page(struct bitmap *bitmap, struct page *page, int wait)
 288 {
 289         struct buffer_head *bh;
 290
 291         if (bitmap->storage.file == NULL) {
 292                 switch (write_sb_page(bitmap, page, wait)) {
 293                 case -EINVAL:
 294                         set_bit(BITMAP_WRITE_ERROR, &bitmap->flags);
 295                 }
 296         } else {
 297
 298                 bh = page_buffers(page);
 299
 300                 while (bh && bh->b_blocknr) {
 301                         atomic_inc(&bitmap->pending_writes);
 302                         set_buffer_locked(bh);
 303                         set_buffer_mapped(bh);
 304                         submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
 305                         bh = bh->b_this_page;
 306                 }
 307
 308                 if (wait)
 309                         wait_event(bitmap->write_wait,
 310                                    atomic_read(&bitmap->pending_writes)==0);
 311         }
 312         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
 313                 bitmap_file_kick(bitmap);
 314 }
 315
 316 static void end_bitmap_write(struct buffer_head *bh, int uptodate)
 317 {
 318         struct bitmap *bitmap = bh->b_private;
 319
 320         if (!uptodate)
 321                 set_bit(BITMAP_WRITE_ERROR, &bitmap->flags);
 322         if (atomic_dec_and_test(&bitmap->pending_writes))
 323                 wake_up(&bitmap->write_wait);
 324 }
 325
 326 /* copied from buffer.c */
 327 static void
 328 __clear_page_buffers(struct page *page)
 329 {
 330         ClearPagePrivate(page);
 331         set_page_private(page, 0);
 332         put_page(page);
 333 }
 334 static void free_buffers(struct page *page)
 335 {
 336         struct buffer_head *bh;
 337
 338         if (!PagePrivate(page))
 339                 return;
 340
 341         bh = page_buffers(page);
 342         while (bh) {
 343                 struct buffer_head *next = bh->b_this_page;
 344                 free_buffer_head(bh);
 345                 bh = next;
 346         }
 347         __clear_page_buffers(page);
 348         put_page(page);
 349 }
 350
 351 /* read a page from a file.
 352  * We both read the page, and attach buffers to the page to record the
 353  * address of each block (using bmap).  These addresses will be used
 354  * to write the block later, completely bypassing the filesystem.
 355  * This usage is similar to how swap files are handled, and allows us
 356  * to write to a file with no concerns of memory allocation failing.
 357  */
 358 static int read_page(struct file *file, unsigned long index,
 359                      struct bitmap *bitmap,
 360                      unsigned long count,
 361                      struct page *page)
 362 {
 363         int ret = 0;
 364         struct inode *inode = file_inode(file);
 365         struct buffer_head *bh;
 366         sector_t block;
 367
 368         pr_debug("read bitmap file (%dB @ %llu)\n", (int)PAGE_SIZE,
 369                  (unsigned long long)index << PAGE_SHIFT);
 370
 371         bh = alloc_page_buffers(page, 1<<inode->i_blkbits, 0);
 372         if (!bh) {
 373                 ret = -ENOMEM;
 374                 goto out;
 375         }
 376         attach_page_buffers(page, bh);
 377         block = index << (PAGE_SHIFT - inode->i_blkbits);
 378         while (bh) {
 379                 if (count == 0)
 380                         bh->b_blocknr = 0;
 381                 else {
 382                         bh->b_blocknr = bmap(inode, block);
 383                         if (bh->b_blocknr == 0) {
 384                                 /* Cannot use this file! */
 385                                 ret = -EINVAL;
 386                                 goto out;
 387                         }
 388                         bh->b_bdev = inode->i_sb->s_bdev;
 389                         if (count < (1<<inode->i_blkbits))
 390                                 count = 0;
 391                         else
 392                                 count -= (1<<inode->i_blkbits);
 393
 394                         bh->b_end_io = end_bitmap_write;
 395                         bh->b_private = bitmap;
 396                         atomic_inc(&bitmap->pending_writes);
 397                         set_buffer_locked(bh);
 398                         set_buffer_mapped(bh);
 399                         submit_bh(REQ_OP_READ, 0, bh);
 400                 }
 401                 block++;
 402                 bh = bh->b_this_page;
 403         }
 404         page->index = index;
 405
 406         wait_event(bitmap->write_wait,
 407                    atomic_read(&bitmap->pending_writes)==0);
 408         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
 409                 ret = -EIO;
 410 out:
 411         if (ret)
 412                 pr_err("md: bitmap read error: (%dB @ %llu): %d\n",
 413                        (int)PAGE_SIZE,
 414                        (unsigned long long)index << PAGE_SHIFT,
 415                        ret);
 416         return ret;
 417 }
 418
 419 /*
 420  * bitmap file superblock operations
 421  */
 422
 423 /*
 424  * bitmap_wait_writes() should be called before writing any bitmap
 425  * blocks, to ensure previous writes, particularly from
 426  * bitmap_daemon_work(), have completed.
 427  */
 428 static void bitmap_wait_writes(struct bitmap *bitmap)
 429 {
 430         if (bitmap->storage.file)
 431                 wait_event(bitmap->write_wait,
 432                            atomic_read(&bitmap->pending_writes)==0);
 433         else
 434                 /* Note that we ignore the return value.  The writes
 435                  * might have failed, but that would just mean that
 436                  * some bits which should be cleared haven't been,
 437                  * which is safe.  The relevant bitmap blocks will
 438                  * probably get written again, but there is no great
 439                  * loss if they aren't.
 440                  */
 441                 md_super_wait(bitmap->mddev);
 442 }
 443
 444
 445 /* update the event counter and sync the superblock to disk */
 446 void bitmap_update_sb(struct bitmap *bitmap)
 447 {
 448         bitmap_super_t *sb;
 449
 450         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
 451                 return;
 452         if (bitmap->mddev->bitmap_info.external)
 453                 return;
 454         if (!bitmap->storage.sb_page) /* no superblock */
 455                 return;
 456         sb = kmap_atomic(bitmap->storage.sb_page);
 457         sb->events = cpu_to_le64(bitmap->mddev->events);
 458         if (bitmap->mddev->events < bitmap->events_cleared)
 459                 /* rocking back to read-only */
 460                 bitmap->events_cleared = bitmap->mddev->events;
 461         sb->events_cleared = cpu_to_le64(bitmap->events_cleared);
 462         sb->state = cpu_to_le32(bitmap->flags);
 463         /* Just in case these have been changed via sysfs: */
 464         sb->daemon_sleep = cpu_to_le32(bitmap->mddev->bitmap_info.daemon_sleep/HZ);
 465         sb->write_behind = cpu_to_le32(bitmap->mddev->bitmap_info.max_write_behind);
 466         /* This might have been changed by a reshape */
 467         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 468         sb->chunksize = cpu_to_le32(bitmap->mddev->bitmap_info.chunksize);
 469         sb->nodes = cpu_to_le32(bitmap->mddev->bitmap_info.nodes);
 470         sb->sectors_reserved = cpu_to_le32(bitmap->mddev->
 471                                            bitmap_info.space);
 472         kunmap_atomic(sb);
 473         write_page(bitmap, bitmap->storage.sb_page, 1);
 474 }
 475 EXPORT_SYMBOL(bitmap_update_sb);
 476
 477 /* print out the bitmap file superblock */
 478 void bitmap_print_sb(struct bitmap *bitmap)
 479 {
 480         bitmap_super_t *sb;
 481
 482         if (!bitmap || !bitmap->storage.sb_page)
 483                 return;
 484         sb = kmap_atomic(bitmap->storage.sb_page);
 485         pr_debug("%s: bitmap file superblock:\n", bmname(bitmap));
 486         pr_debug("         magic: %08x\n", le32_to_cpu(sb->magic));
 487         pr_debug("       version: %d\n", le32_to_cpu(sb->version));
 488         pr_debug("          uuid: %08x.%08x.%08x.%08x\n",
 489                  le32_to_cpu(*(__u32 *)(sb->uuid+0)),
 490                  le32_to_cpu(*(__u32 *)(sb->uuid+4)),
 491                  le32_to_cpu(*(__u32 *)(sb->uuid+8)),
 492                  le32_to_cpu(*(__u32 *)(sb->uuid+12)));
 493         pr_debug("        events: %llu\n",
 494                  (unsigned long long) le64_to_cpu(sb->events));
 495         pr_debug("events cleared: %llu\n",
 496                  (unsigned long long) le64_to_cpu(sb->events_cleared));
 497         pr_debug("         state: %08x\n", le32_to_cpu(sb->state));
 498         pr_debug("     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
 499         pr_debug("  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
 500         pr_debug("     sync size: %llu KB\n",
 501                  (unsigned long long)le64_to_cpu(sb->sync_size)/2);
 502         pr_debug("max write behind: %d\n", le32_to_cpu(sb->write_behind));
 503         kunmap_atomic(sb);
 504 }
 505
 506 /*
 507  * bitmap_new_disk_sb
 508  * @bitmap
 509  *
 510  * This function is somewhat the reverse of bitmap_read_sb.  bitmap_read_sb
 511  * reads and verifies the on-disk bitmap superblock and populates bitmap_info.
 512  * This function verifies 'bitmap_info' and populates the on-disk bitmap
 513  * structure, which is to be written to disk.
 514  *
 515  * Returns: 0 on success, -Exxx on error
 516  */
 517 static int bitmap_new_disk_sb(struct bitmap *bitmap)
 518 {
 519         bitmap_super_t *sb;
 520         unsigned long chunksize, daemon_sleep, write_behind;
 521
 522         bitmap->storage.sb_page = alloc_page(GFP_KERNEL | __GFP_ZERO);
 523         if (bitmap->storage.sb_page == NULL)
 524                 return -ENOMEM;
 525         bitmap->storage.sb_page->index = 0;
 526
 527         sb = kmap_atomic(bitmap->storage.sb_page);
 528
 529         sb->magic = cpu_to_le32(BITMAP_MAGIC);
 530         sb->version = cpu_to_le32(BITMAP_MAJOR_HI);
 531
 532         chunksize = bitmap->mddev->bitmap_info.chunksize;
 533         BUG_ON(!chunksize);
 534         if (!is_power_of_2(chunksize)) {
 535                 kunmap_atomic(sb);
 536                 pr_warn("bitmap chunksize not a power of 2\n");
 537                 return -EINVAL;
 538         }
 539         sb->chunksize = cpu_to_le32(chunksize);
 540
 541         daemon_sleep = bitmap->mddev->bitmap_info.daemon_sleep;
 542         if (!daemon_sleep || (daemon_sleep > MAX_SCHEDULE_TIMEOUT)) {
 543                 pr_debug("Choosing daemon_sleep default (5 sec)\n");
 544                 daemon_sleep = 5 * HZ;
 545         }
 546         sb->daemon_sleep = cpu_to_le32(daemon_sleep);
 547         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 548
 549         /*
 550          * FIXME: write_behind for RAID1.  If not specified, what
 551          * is a good choice?  We choose COUNTER_MAX / 2 arbitrarily.
 552          */
 553         write_behind = bitmap->mddev->bitmap_info.max_write_behind;
 554         if (write_behind > COUNTER_MAX)
 555                 write_behind = COUNTER_MAX / 2;
 556         sb->write_behind = cpu_to_le32(write_behind);
 557         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 558
 559         /* keep the array size field of the bitmap superblock up to date */
 560         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 561
 562         memcpy(sb->uuid, bitmap->mddev->uuid, 16);
 563
 564         set_bit(BITMAP_STALE, &bitmap->flags);
 565         sb->state = cpu_to_le32(bitmap->flags);
 566         bitmap->events_cleared = bitmap->mddev->events;
 567         sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
 568         bitmap->mddev->bitmap_info.nodes = 0;
 569
 570         kunmap_atomic(sb);
 571
 572         return 0;
 573 }
 574
 575 /* read the superblock from the bitmap file and initialize some bitmap fields */
 576 static int bitmap_read_sb(struct bitmap *bitmap)
 577 {
 578         char *reason = NULL;
 579         bitmap_super_t *sb;
 580         unsigned long chunksize, daemon_sleep, write_behind;
 581         unsigned long long events;
 582         int nodes = 0;
 583         unsigned long sectors_reserved = 0;
 584         int err = -EINVAL;
 585         struct page *sb_page;
 586         loff_t offset = bitmap->mddev->bitmap_info.offset;
 587
 588         if (!bitmap->storage.file && !bitmap->mddev->bitmap_info.offset) {
 589                 chunksize = 128 * 1024 * 1024;
 590                 daemon_sleep = 5 * HZ;
 591                 write_behind = 0;
 592                 set_bit(BITMAP_STALE, &bitmap->flags);
 593                 err = 0;
 594                 goto out_no_sb;
 595         }
 596         /* page 0 is the superblock, read it... */
 597         sb_page = alloc_page(GFP_KERNEL);
 598         if (!sb_page)
 599                 return -ENOMEM;
 600         bitmap->storage.sb_page = sb_page;
 601
 602 re_read:
 603         /* If cluster_slot is set, the cluster is setup */
 604         if (bitmap->cluster_slot >= 0) {
 605                 sector_t bm_blocks = bitmap->mddev->resync_max_sectors;
 606
 607                 sector_div(bm_blocks,
 608                            bitmap->mddev->bitmap_info.chunksize >> 9);
 609                 /* bits to bytes */
 610                 bm_blocks = ((bm_blocks+7) >> 3) + sizeof(bitmap_super_t);
 611                 /* to 4k blocks */
 612                 bm_blocks = DIV_ROUND_UP_SECTOR_T(bm_blocks, 4096);
 613                 offset = bitmap->mddev->bitmap_info.offset + (bitmap->cluster_slot * (bm_blocks << 3));
 614                 pr_debug("%s:%d bm slot: %d offset: %llu\n", __func__, __LINE__,
 615                         bitmap->cluster_slot, offset);
 616         }
 617
 618         if (bitmap->storage.file) {
 619                 loff_t isize = i_size_read(bitmap->storage.file->f_mapping->host);
 620                 int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
 621
 622                 err = read_page(bitmap->storage.file, 0,
 623                                 bitmap, bytes, sb_page);
 624         } else {
 625                 err = read_sb_page(bitmap->mddev,
 626                                    offset,
 627                                    sb_page,
 628                                    0, sizeof(bitmap_super_t));
 629         }
 630         if (err)
 631                 return err;
 632
 633         err = -EINVAL;
 634         sb = kmap_atomic(sb_page);
 635
 636         chunksize = le32_to_cpu(sb->chunksize);
 637         daemon_sleep = le32_to_cpu(sb->daemon_sleep) * HZ;
 638         write_behind = le32_to_cpu(sb->write_behind);
 639         sectors_reserved = le32_to_cpu(sb->sectors_reserved);
 640         /* Setup nodes/clustername only if bitmap version is
 641          * cluster-compatible
 642          */
 643         if (sb->version == cpu_to_le32(BITMAP_MAJOR_CLUSTERED)) {
 644                 nodes = le32_to_cpu(sb->nodes);
 645                 strlcpy(bitmap->mddev->bitmap_info.cluster_name,
 646                                 sb->cluster_name, 64);
 647         }
 648
 649         /* verify that the bitmap-specific fields are valid */
 650         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
 651                 reason = "bad magic";
 652         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
 653                  le32_to_cpu(sb->version) > BITMAP_MAJOR_CLUSTERED)
 654                 reason = "unrecognized superblock version";
 655         else if (chunksize < 512)
 656                 reason = "bitmap chunksize too small";
 657         else if (!is_power_of_2(chunksize))
 658                 reason = "bitmap chunksize not a power of 2";
 659         else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT)
 660                 reason = "daemon sleep period out of range";
 661         else if (write_behind > COUNTER_MAX)
 662                 reason = "write-behind limit out of range (0 - 16383)";
 663         if (reason) {
 664                 pr_warn("%s: invalid bitmap file superblock: %s\n",
 665                         bmname(bitmap), reason);
 666                 goto out;
 667         }
 668
 669         /* keep the array size field of the bitmap superblock up to date */
 670         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 671
 672         if (bitmap->mddev->persistent) {
 673                 /*
 674                  * We have a persistent array superblock, so compare the
 675                  * bitmap's UUID and event counter to the mddev's
 676                  */
 677                 if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
 678                         pr_warn("%s: bitmap superblock UUID mismatch\n",
 679                                 bmname(bitmap));
 680                         goto out;
 681                 }
 682                 events = le64_to_cpu(sb->events);
 683                 if (!nodes && (events < bitmap->mddev->events)) {
 684                         pr_warn("%s: bitmap file is out of date (%llu < %llu) -- forcing full recovery\n",
 685                                 bmname(bitmap), events,
 686                                 (unsigned long long) bitmap->mddev->events);
 687                         set_bit(BITMAP_STALE, &bitmap->flags);
 688                 }
 689         }
 690
 691         /* assign fields using values from superblock */
 692         bitmap->flags |= le32_to_cpu(sb->state);
 693         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
 694                 set_bit(BITMAP_HOSTENDIAN, &bitmap->flags);
 695         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
 696         strlcpy(bitmap->mddev->bitmap_info.cluster_name, sb->cluster_name, 64);
 697         err = 0;
 698
 699 out:
 700         kunmap_atomic(sb);
 701         /* Assigning chunksize is required for "re_read" */
 702         bitmap->mddev->bitmap_info.chunksize = chunksize;
 703         if (err == 0 && nodes && (bitmap->cluster_slot < 0)) {
 704                 err = md_setup_cluster(bitmap->mddev, nodes);
 705                 if (err) {
 706                         pr_warn("%s: Could not setup cluster service (%d)\n",
 707                                 bmname(bitmap), err);
 708                         goto out_no_sb;
 709                 }
 710                 bitmap->cluster_slot = md_cluster_ops->slot_number(bitmap->mddev);
 711                 goto re_read;
 712         }
 713
 714
 715 out_no_sb:
 716         if (test_bit(BITMAP_STALE, &bitmap->flags))
 717                 bitmap->events_cleared = bitmap->mddev->events;
 718         bitmap->mddev->bitmap_info.chunksize = chunksize;
 719         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 720         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 721         bitmap->mddev->bitmap_info.nodes = nodes;
 722         if (bitmap->mddev->bitmap_info.space == 0 ||
 723             bitmap->mddev->bitmap_info.space > sectors_reserved)
 724                 bitmap->mddev->bitmap_info.space = sectors_reserved;
 725         if (err) {
 726                 bitmap_print_sb(bitmap);
 727                 if (bitmap->cluster_slot < 0)
 728                         md_cluster_stop(bitmap->mddev);
 729         }
 730         return err;
 731 }
 732
 733 /*
 734  * general bitmap file operations
 735  */
 736
 737 /*
 738  * on-disk bitmap:
 739  *
 740  * Use one bit per "chunk" (block set). We do the disk I/O on the bitmap
 741  * file a page at a time. There's a superblock at the start of the file.
 742  */
 743 /* calculate the index of the page that contains this bit */
 744 static inline unsigned long file_page_index(struct bitmap_storage *store,
 745                                             unsigned long chunk)
 746 {
 747         if (store->sb_page)
 748                 chunk += sizeof(bitmap_super_t) << 3;
 749         return chunk >> PAGE_BIT_SHIFT;
 750 }
 751
 752 /* calculate the (bit) offset of this bit within a page */
 753 static inline unsigned long file_page_offset(struct bitmap_storage *store,
 754                                              unsigned long chunk)
 755 {
 756         if (store->sb_page)
 757                 chunk += sizeof(bitmap_super_t) << 3;
 758         return chunk & (PAGE_BITS - 1);
 759 }
 760
 761 /*
 762  * return a pointer to the page in the filemap that contains the given bit
 763  *
 764  */
 765 static inline struct page *filemap_get_page(struct bitmap_storage *store,
 766                                             unsigned long chunk)
 767 {
 768         if (file_page_index(store, chunk) >= store->file_pages)
 769                 return NULL;
 770         return store->filemap[file_page_index(store, chunk)];
 771 }
 772
 773 static int bitmap_storage_alloc(struct bitmap_storage *store,
 774                                 unsigned long chunks, int with_super,
 775                                 int slot_number)
 776 {
 777         int pnum, offset = 0;
 778         unsigned long num_pages;
 779         unsigned long bytes;
 780
 781         bytes = DIV_ROUND_UP(chunks, 8);
 782         if (with_super)
 783                 bytes += sizeof(bitmap_super_t);
 784
 785         num_pages = DIV_ROUND_UP(bytes, PAGE_SIZE);
 786         offset = slot_number * num_pages;
 787
 788         store->filemap = kmalloc(sizeof(struct page *)
 789                                  * num_pages, GFP_KERNEL);
 790         if (!store->filemap)
 791                 return -ENOMEM;
 792
 793         if (with_super && !store->sb_page) {
 794                 store->sb_page = alloc_page(GFP_KERNEL|__GFP_ZERO);
 795                 if (store->sb_page == NULL)
 796                         return -ENOMEM;
 797         }
 798
 799         pnum = 0;
 800         if (store->sb_page) {
 801                 store->filemap[0] = store->sb_page;
 802                 pnum = 1;
 803                 store->sb_page->index = offset;
 804         }
 805
 806         for ( ; pnum < num_pages; pnum++) {
 807                 store->filemap[pnum] = alloc_page(GFP_KERNEL|__GFP_ZERO);
 808                 if (!store->filemap[pnum]) {
 809                         store->file_pages = pnum;
 810                         return -ENOMEM;
 811                 }
 812                 store->filemap[pnum]->index = pnum + offset;
 813         }
 814         store->file_pages = pnum;
 815
 816         /* We need 4 bits per page, rounded up to a multiple
 817          * of sizeof(unsigned long) */
 818         store->filemap_attr = kzalloc(
 819                 roundup(DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
 820                 GFP_KERNEL);
 821         if (!store->filemap_attr)
 822                 return -ENOMEM;
 823
 824         store->bytes = bytes;
 825
 826         return 0;
 827 }
 828
 829 static void bitmap_file_unmap(struct bitmap_storage *store)
 830 {
 831         struct page **map, *sb_page;
 832         int pages;
 833         struct file *file;
 834
 835         file = store->file;
 836         map = store->filemap;
 837         pages = store->file_pages;
 838         sb_page = store->sb_page;
 839
 840         while (pages--)
 841                 if (map[pages] != sb_page) /* 0 is sb_page, release it below */
 842                         free_buffers(map[pages]);
 843         kfree(map);
 844         kfree(store->filemap_attr);
 845
 846         if (sb_page)
 847                 free_buffers(sb_page);
 848
 849         if (file) {
 850                 struct inode *inode = file_inode(file);
 851                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
 852                 fput(file);
 853         }
 854 }
 855
 856 /*
 857  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
 858  * then it is no longer reliable, so we stop using it and we mark the file
 859  * as failed in the superblock
 860  */
 861 static void bitmap_file_kick(struct bitmap *bitmap)
 862 {
 863         char *path, *ptr = NULL;
 864
 865         if (!test_and_set_bit(BITMAP_STALE, &bitmap->flags)) {
 866                 bitmap_update_sb(bitmap);
 867
 868                 if (bitmap->storage.file) {
 869                         path = kmalloc(PAGE_SIZE, GFP_KERNEL);
 870                         if (path)
 871                                 ptr = file_path(bitmap->storage.file,
 872                                              path, PAGE_SIZE);
 873
 874                         pr_warn("%s: kicking failed bitmap file %s from array!\n",
 875                                 bmname(bitmap), IS_ERR(ptr) ? "" : ptr);
 876
 877                         kfree(path);
 878                 } else
 879                         pr_warn("%s: disabling internal bitmap due to errors\n",
 880                                 bmname(bitmap));
 881         }
 882 }
 883
 884 enum bitmap_page_attr {
 885         BITMAP_PAGE_DIRTY = 0,     /* there are set bits that need to be synced */
 886         BITMAP_PAGE_PENDING = 1,   /* there are bits that are being cleaned.
 887                                     * i.e. counter is 1 or 2. */
 888         BITMAP_PAGE_NEEDWRITE = 2, /* there are cleared bits that need to be synced */
 889 };
 890
 891 static inline void set_page_attr(struct bitmap *bitmap, int pnum,
 892                                  enum bitmap_page_attr attr)
 893 {
 894         set_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 895 }
 896
 897 static inline void clear_page_attr(struct bitmap *bitmap, int pnum,
 898                                    enum bitmap_page_attr attr)
 899 {
 900         clear_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 901 }
 902
 903 static inline int test_page_attr(struct bitmap *bitmap, int pnum,
 904                                  enum bitmap_page_attr attr)
 905 {
 906         return test_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 907 }
 908
 909 static inline int test_and_clear_page_attr(struct bitmap *bitmap, int pnum,
 910                                            enum bitmap_page_attr attr)
 911 {
 912         return test_and_clear_bit((pnum<<2) + attr,
 913                                   bitmap->storage.filemap_attr);
 914 }
 915 /*
 916  * bitmap_file_set_bit -- called before performing a write to the md device
 917  * to set (and eventually sync) a particular bit in the bitmap file
 918  *
 919  * we set the bit immediately, then we record the page number so that
 920  * when an unplug occurs, we can flush the dirty pages out to disk
 921  */
 922 static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 923 {
 924         unsigned long bit;
 925         struct page *page;
 926         void *kaddr;
 927         unsigned long chunk = block >> bitmap->counts.chunkshift;
 928         struct bitmap_storage *store = &bitmap->storage;
 929         unsigned long node_offset = 0;
 930
 931         if (mddev_is_clustered(bitmap->mddev))
 932                 node_offset = bitmap->cluster_slot * store->file_pages;
 933
 934         page = filemap_get_page(&bitmap->storage, chunk);
 935         if (!page)
 936                 return;
 937         bit = file_page_offset(&bitmap->storage, chunk);
 938
 939         /* set the bit */
 940         kaddr = kmap_atomic(page);
 941         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
 942                 set_bit(bit, kaddr);
 943         else
 944                 set_bit_le(bit, kaddr);
 945         kunmap_atomic(kaddr);
 946         pr_debug("set file bit %lu page %lu\n", bit, page->index);
 947         /* record page number so it gets flushed to disk when unplug occurs */
 948         set_page_attr(bitmap, page->index - node_offset, BITMAP_PAGE_DIRTY);
 949 }
 950
 951 static void bitmap_file_clear_bit(struct bitmap *bitmap, sector_t block)
 952 {
 953         unsigned long bit;
 954         struct page *page;
 955         void *paddr;
 956         unsigned long chunk = block >> bitmap->counts.chunkshift;
 957         struct bitmap_storage *store = &bitmap->storage;
 958         unsigned long node_offset = 0;
 959
 960         if (mddev_is_clustered(bitmap->mddev))
 961                 node_offset = bitmap->cluster_slot * store->file_pages;
 962
 963         page = filemap_get_page(&bitmap->storage, chunk);
 964         if (!page)
 965                 return;
 966         bit = file_page_offset(&bitmap->storage, chunk);
 967         paddr = kmap_atomic(page);
 968         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
 969                 clear_bit(bit, paddr);
 970         else
 971                 clear_bit_le(bit, paddr);
 972         kunmap_atomic(paddr);
 973         if (!test_page_attr(bitmap, page->index - node_offset, BITMAP_PAGE_NEEDWRITE)) {
 974                 set_page_attr(bitmap, page->index - node_offset, BITMAP_PAGE_PENDING);
 975                 bitmap->allclean = 0;
 976         }
 977 }
 978
 979 static int bitmap_file_test_bit(struct bitmap *bitmap, sector_t block)
 980 {
 981         unsigned long bit;
 982         struct page *page;
 983         void *paddr;
 984         unsigned long chunk = block >> bitmap->counts.chunkshift;
 985         int set = 0;
 986
 987         page = filemap_get_page(&bitmap->storage, chunk);
 988         if (!page)
 989                 return -EINVAL;
 990         bit = file_page_offset(&bitmap->storage, chunk);
 991         paddr = kmap_atomic(page);
 992         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
 993                 set = test_bit(bit, paddr);
 994         else
 995                 set = test_bit_le(bit, paddr);
 996         kunmap_atomic(paddr);
 997         return set;
 998 }
 999
1000
1001 /* this gets called when the md device is ready to unplug its underlying
1002  * (slave) device queues -- before we let any writes go down, we need to
1003  * sync the dirty pages of the bitmap file to disk */
1004 void bitmap_unplug(struct bitmap *bitmap)
1005 {
1006         unsigned long i;
1007         int dirty, need_write;
1008         int writing = 0;
1009
1010         if (!bitmap || !bitmap->storage.filemap ||
1011             test_bit(BITMAP_STALE, &bitmap->flags))
1012                 return;
1013
1014         /* look at each page to see if there are any set bits that need to be
1015          * flushed out to disk */
1016         for (i = 0; i < bitmap->storage.file_pages; i++) {
1017                 if (!bitmap->storage.filemap)
1018                         return;
1019                 dirty = test_and_clear_page_attr(bitmap, i, BITMAP_PAGE_DIRTY);
1020                 need_write = test_and_clear_page_attr(bitmap, i,
1021                                                       BITMAP_PAGE_NEEDWRITE);
1022                 if (dirty || need_write) {
1023                         if (!writing) {
1024                                 bitmap_wait_writes(bitmap);
1025                                 if (bitmap->mddev->queue)
1026                                         blk_add_trace_msg(bitmap->mddev->queue,
1027                                                           "md bitmap_unplug");
1028                         }
1029                         clear_page_attr(bitmap, i, BITMAP_PAGE_PENDING);
1030                         write_page(bitmap, bitmap->storage.filemap[i], 0);
1031                         writing = 1;
1032                 }
1033         }
1034         if (writing)
1035                 bitmap_wait_writes(bitmap);
1036
1037         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
1038                 bitmap_file_kick(bitmap);
1039 }
1040 EXPORT_SYMBOL(bitmap_unplug);
1041
1042 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
1043 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
1044  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
1045  * memory mapping of the bitmap file
1046  * Special cases:
1047  *   if there's no bitmap file, or if the bitmap file had been
1048  *   previously kicked from the array, we mark all the bits as
1049  *   1's in order to cause a full resync.
1050  *
1051  * We ignore all bits for sectors that end earlier than 'start'.
1052  * This is used when reading an out-of-date bitmap...
1053  */
1054 static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
1055 {
1056         unsigned long i, chunks, index, oldindex, bit, node_offset = 0;
1057         struct page *page = NULL;
1058         unsigned long bit_cnt = 0;
1059         struct file *file;
1060         unsigned long offset;
1061         int outofdate;
1062         int ret = -ENOSPC;
1063         void *paddr;
1064         struct bitmap_storage *store = &bitmap->storage;
1065
1066         chunks = bitmap->counts.chunks;
1067         file = store->file;
1068
1069         if (!file && !bitmap->mddev->bitmap_info.offset) {
1070                 /* No permanent bitmap - fill with '1s'. */
1071                 store->filemap = NULL;
1072                 store->file_pages = 0;
1073                 for (i = 0; i < chunks ; i++) {
1074                         /* if the disk bit is set, set the memory bit */
1075                         int needed = ((sector_t)(i+1) << (bitmap->counts.chunkshift)
1076                                       >= start);
1077                         bitmap_set_memory_bits(bitmap,
1078                                                (sector_t)i << bitmap->counts.chunkshift,
1079                                                needed);
1080                 }
1081                 return 0;
1082         }
1083
1084         outofdate = test_bit(BITMAP_STALE, &bitmap->flags);
1085         if (outofdate)
1086                 pr_warn("%s: bitmap file is out of date, doing full recovery\n", bmname(bitmap));
1087
1088         if (file && i_size_read(file->f_mapping->host) < store->bytes) {
1089                 pr_warn("%s: bitmap file too short %lu < %lu\n",
1090                         bmname(bitmap),
1091                         (unsigned long) i_size_read(file->f_mapping->host),
1092                         store->bytes);
1093                 goto err;
1094         }
1095
1096         oldindex = ~0L;
1097         offset = 0;
1098         if (!bitmap->mddev->bitmap_info.external)
1099                 offset = sizeof(bitmap_super_t);
1100
1101         if (mddev_is_clustered(bitmap->mddev))
1102                 node_offset = bitmap->cluster_slot * (DIV_ROUND_UP(store->bytes, PAGE_SIZE));
1103
1104         for (i = 0; i < chunks; i++) {
1105                 int b;
1106                 index = file_page_index(&bitmap->storage, i);
1107                 bit = file_page_offset(&bitmap->storage, i);
1108                 if (index != oldindex) { /* this is a new page, read it in */
1109                         int count;
1110                         /* unmap the old page, we're done with it */
1111                         if (index == store->file_pages-1)
1112                                 count = store->bytes - index * PAGE_SIZE;
1113                         else
1114                                 count = PAGE_SIZE;
1115                         page = store->filemap[index];
1116                         if (file)
1117                                 ret = read_page(file, index, bitmap,
1118                                                 count, page);
1119                         else
1120                                 ret = read_sb_page(
1121                                         bitmap->mddev,
1122                                         bitmap->mddev->bitmap_info.offset,
1123                                         page,
1124                                         index + node_offset, count);
1125
1126                         if (ret)
1127                                 goto err;
1128
1129                         oldindex = index;
1130
1131                         if (outofdate) {
1132                                 /*
1133                                  * if bitmap is out of date, dirty the
1134                                  * whole page and write it out
1135                                  */
1136                                 paddr = kmap_atomic(page);
1137                                 memset(paddr + offset, 0xff,
1138                                        PAGE_SIZE - offset);
1139                                 kunmap_atomic(paddr);
1140                                 write_page(bitmap, page, 1);
1141
1142                                 ret = -EIO;
1143                                 if (test_bit(BITMAP_WRITE_ERROR,
1144                                              &bitmap->flags))
1145                                         goto err;
1146                         }
1147                 }
1148                 paddr = kmap_atomic(page);
1149                 if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
1150                         b = test_bit(bit, paddr);
1151                 else
1152                         b = test_bit_le(bit, paddr);
1153                 kunmap_atomic(paddr);
1154                 if (b) {
1155                         /* if the disk bit is set, set the memory bit */
1156                         int needed = ((sector_t)(i+1) << bitmap->counts.chunkshift
1157                                       >= start);
1158                         bitmap_set_memory_bits(bitmap,
1159                                                (sector_t)i << bitmap->counts.chunkshift,
1160                                                needed);
1161                         bit_cnt++;
1162                 }
1163                 offset = 0;
1164         }
1165
1166         pr_debug("%s: bitmap initialized from disk: read %lu pages, set %lu of %lu bits\n",
1167                  bmname(bitmap), store->file_pages,
1168                  bit_cnt, chunks);
1169
1170         return 0;
1171
1172  err:
1173         pr_warn("%s: bitmap initialisation failed: %d\n",
1174                 bmname(bitmap), ret);
1175         return ret;
1176 }
1177
1178 void bitmap_write_all(struct bitmap *bitmap)
1179 {
1180         /* We don't actually write all bitmap blocks here,
1181          * just flag them as needing to be written
1182          */
1183         int i;
1184
1185         if (!bitmap || !bitmap->storage.filemap)
1186                 return;
1187         if (bitmap->storage.file)
1188                 /* Only one copy, so nothing needed */
1189                 return;
1190
1191         for (i = 0; i < bitmap->storage.file_pages; i++)
1192                 set_page_attr(bitmap, i,
1193                               BITMAP_PAGE_NEEDWRITE);
1194         bitmap->allclean = 0;
1195 }
1196
1197 static void bitmap_count_page(struct bitmap_counts *bitmap,
1198                               sector_t offset, int inc)
1199 {
1200         sector_t chunk = offset >> bitmap->chunkshift;
1201         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1202         bitmap->bp[page].count += inc;
1203         bitmap_checkfree(bitmap, page);
1204 }
1205
1206 static void bitmap_set_pending(struct bitmap_counts *bitmap, sector_t offset)
1207 {
1208         sector_t chunk = offset >> bitmap->chunkshift;
1209         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1210         struct bitmap_page *bp = &bitmap->bp[page];
1211
1212         if (!bp->pending)
1213                 bp->pending = 1;
1214 }
1215
1216 static bitmap_counter_t *bitmap_get_counter(struct bitmap_counts *bitmap,
1217                                             sector_t offset, sector_t *blocks,
1218                                             int create);
1219
1220 /*
1221  * bitmap daemon -- periodically wakes up to clean bits and flush pages
1222  *                      out to disk
1223  */
1224
1225 void bitmap_daemon_work(struct mddev *mddev)
1226 {
1227         struct bitmap *bitmap;
1228         unsigned long j;
1229         unsigned long nextpage;
1230         sector_t blocks;
1231         struct bitmap_counts *counts;
1232
1233         /* Use a mutex to guard daemon_work against
1234          * bitmap_destroy.
1235          */
1236         mutex_lock(&mddev->bitmap_info.mutex);
1237         bitmap = mddev->bitmap;
1238         if (bitmap == NULL) {
1239                 mutex_unlock(&mddev->bitmap_info.mutex);
1240                 return;
1241         }
1242         if (time_before(jiffies, bitmap->daemon_lastrun
1243                         + mddev->bitmap_info.daemon_sleep))
1244                 goto done;
1245
1246         bitmap->daemon_lastrun = jiffies;
1247         if (bitmap->allclean) {
1248                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1249                 goto done;
1250         }
1251         bitmap->allclean = 1;
1252
1253         if (bitmap->mddev->queue)
1254                 blk_add_trace_msg(bitmap->mddev->queue,
1255                                   "md bitmap_daemon_work");
1256
1257         /* Any file-page which is PENDING now needs to be written.
1258          * So set NEEDWRITE now, then after we make any last-minute changes
1259          * we will write it.
1260          */
1261         for (j = 0; j < bitmap->storage.file_pages; j++)
1262                 if (test_and_clear_page_attr(bitmap, j,
1263                                              BITMAP_PAGE_PENDING))
1264                         set_page_attr(bitmap, j,
1265                                       BITMAP_PAGE_NEEDWRITE);
1266
1267         if (bitmap->need_sync &&
1268             mddev->bitmap_info.external == 0) {
1269                 /* Arrange for superblock update as well as
1270                  * other changes */
1271                 bitmap_super_t *sb;
1272                 bitmap->need_sync = 0;
1273                 if (bitmap->storage.filemap) {
1274                         sb = kmap_atomic(bitmap->storage.sb_page);
1275                         sb->events_cleared =
1276                                 cpu_to_le64(bitmap->events_cleared);
1277                         kunmap_atomic(sb);
1278                         set_page_attr(bitmap, 0,
1279                                       BITMAP_PAGE_NEEDWRITE);
1280                 }
1281         }
1282         /* Now look at the bitmap counters and if any are '2' or '1',
1283          * decrement and handle accordingly.
1284          */
1285         counts = &bitmap->counts;
1286         spin_lock_irq(&counts->lock);
1287         nextpage = 0;
1288         for (j = 0; j < counts->chunks; j++) {
1289                 bitmap_counter_t *bmc;
1290                 sector_t  block = (sector_t)j << counts->chunkshift;
1291
1292                 if (j == nextpage) {
1293                         nextpage += PAGE_COUNTER_RATIO;
1294                         if (!counts->bp[j >> PAGE_COUNTER_SHIFT].pending) {
1295                                 j |= PAGE_COUNTER_MASK;
1296                                 continue;
1297                         }
1298                         counts->bp[j >> PAGE_COUNTER_SHIFT].pending = 0;
1299                 }
1300                 bmc = bitmap_get_counter(counts,
1301                                          block,
1302                                          &blocks, 0);
1303
1304                 if (!bmc) {
1305                         j |= PAGE_COUNTER_MASK;
1306                         continue;
1307                 }
1308                 if (*bmc == 1 && !bitmap->need_sync) {
1309                         /* We can clear the bit */
1310                         *bmc = 0;
1311                         bitmap_count_page(counts, block, -1);
1312                         bitmap_file_clear_bit(bitmap, block);
1313                 } else if (*bmc && *bmc <= 2) {
1314                         *bmc = 1;
1315                         bitmap_set_pending(counts, block);
1316                         bitmap->allclean = 0;
1317                 }
1318         }
1319         spin_unlock_irq(&counts->lock);
1320
1321         bitmap_wait_writes(bitmap);
1322         /* Now start writeout on any page in NEEDWRITE that isn't DIRTY.
1323          * DIRTY pages need to be written by bitmap_unplug so it can wait
1324          * for them.
1325          * If we find any DIRTY page we stop there and let bitmap_unplug
1326          * handle all the rest.  This is important in the case where
1327          * the first blocking holds the superblock and it has been updated.
1328          * We mustn't write any other blocks before the superblock.
1329          */
1330         for (j = 0;
1331              j < bitmap->storage.file_pages
1332                      && !test_bit(BITMAP_STALE, &bitmap->flags);
1333              j++) {
1334                 if (test_page_attr(bitmap, j,
1335                                    BITMAP_PAGE_DIRTY))
1336                         /* bitmap_unplug will handle the rest */
1337                         break;
1338                 if (test_and_clear_page_attr(bitmap, j,
1339                                              BITMAP_PAGE_NEEDWRITE)) {
1340                         write_page(bitmap, bitmap->storage.filemap[j], 0);
1341                 }
1342         }
1343
1344  done:
1345         if (bitmap->allclean == 0)
1346                 mddev->thread->timeout =
1347                         mddev->bitmap_info.daemon_sleep;
1348         mutex_unlock(&mddev->bitmap_info.mutex);
1349 }
1350
1351 static bitmap_counter_t *bitmap_get_counter(struct bitmap_counts *bitmap,
1352                                             sector_t offset, sector_t *blocks,
1353                                             int create)
1354 __releases(bitmap->lock)
1355 __acquires(bitmap->lock)
1356 {
1357         /* If 'create', we might release the lock and reclaim it.
1358          * The lock must have been taken with interrupts enabled.
1359          * If !create, we don't release the lock.
1360          */
1361         sector_t chunk = offset >> bitmap->chunkshift;
1362         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1363         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1364         sector_t csize;
1365         int err;
1366
1367         err = bitmap_checkpage(bitmap, page, create, 0);
1368
1369         if (bitmap->bp[page].hijacked ||
1370             bitmap->bp[page].map == NULL)
1371                 csize = ((sector_t)1) << (bitmap->chunkshift +
1372                                           PAGE_COUNTER_SHIFT - 1);
1373         else
1374                 csize = ((sector_t)1) << bitmap->chunkshift;
1375         *blocks = csize - (offset & (csize - 1));
1376
1377         if (err < 0)
1378                 return NULL;
1379
1380         /* now locked ... */
1381
1382         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1383                 /* should we use the first or second counter field
1384                  * of the hijacked pointer? */
1385                 int hi = (pageoff > PAGE_COUNTER_MASK);
1386                 return  &((bitmap_counter_t *)
1387                           &bitmap->bp[page].map)[hi];
1388         } else /* page is allocated */
1389                 return (bitmap_counter_t *)
1390                         &(bitmap->bp[page].map[pageoff]);
1391 }
1392
1393 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1394 {
1395         if (!bitmap)
1396                 return 0;
1397
1398         if (behind) {
1399                 int bw;
1400                 atomic_inc(&bitmap->behind_writes);
1401                 bw = atomic_read(&bitmap->behind_writes);
1402                 if (bw > bitmap->behind_writes_used)
1403                         bitmap->behind_writes_used = bw;
1404
1405                 pr_debug("inc write-behind count %d/%lu\n",
1406                          bw, bitmap->mddev->bitmap_info.max_write_behind);
1407         }
1408
1409         while (sectors) {
1410                 sector_t blocks;
1411                 bitmap_counter_t *bmc;
1412
1413                 spin_lock_irq(&bitmap->counts.lock);
1414                 bmc = bitmap_get_counter(&bitmap->counts, offset, &blocks, 1);
1415                 if (!bmc) {
1416                         spin_unlock_irq(&bitmap->counts.lock);
1417                         return 0;
1418                 }
1419
1420                 if (unlikely(COUNTER(*bmc) == COUNTER_MAX)) {
1421                         DEFINE_WAIT(__wait);
1422                         /* note that it is safe to do the prepare_to_wait
1423                          * after the test as long as we do it before dropping
1424                          * the spinlock.
1425                          */
1426                         prepare_to_wait(&bitmap->overflow_wait, &__wait,
1427                                         TASK_UNINTERRUPTIBLE);
1428                         spin_unlock_irq(&bitmap->counts.lock);
1429                         schedule();
1430                         finish_wait(&bitmap->overflow_wait, &__wait);
1431                         continue;
1432                 }
1433
1434                 switch (*bmc) {
1435                 case 0:
1436                         bitmap_file_set_bit(bitmap, offset);
1437                         bitmap_count_page(&bitmap->counts, offset, 1);
1438                         /* fall through */
1439                 case 1:
1440                         *bmc = 2;
1441                 }
1442
1443                 (*bmc)++;
1444
1445                 spin_unlock_irq(&bitmap->counts.lock);
1446
1447                 offset += blocks;
1448                 if (sectors > blocks)
1449                         sectors -= blocks;
1450                 else
1451                         sectors = 0;
1452         }
1453         return 0;
1454 }
1455 EXPORT_SYMBOL(bitmap_startwrite);
1456
1457 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1458                      int success, int behind)
1459 {
1460         if (!bitmap)
1461                 return;
1462         if (behind) {
1463                 if (atomic_dec_and_test(&bitmap->behind_writes))
1464                         wake_up(&bitmap->behind_wait);
1465                 pr_debug("dec write-behind count %d/%lu\n",
1466                          atomic_read(&bitmap->behind_writes),
1467                          bitmap->mddev->bitmap_info.max_write_behind);
1468         }
1469
1470         while (sectors) {
1471                 sector_t blocks;
1472                 unsigned long flags;
1473                 bitmap_counter_t *bmc;
1474
1475                 spin_lock_irqsave(&bitmap->counts.lock, flags);
1476                 bmc = bitmap_get_counter(&bitmap->counts, offset, &blocks, 0);
1477                 if (!bmc) {
1478                         spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1479                         return;
1480                 }
1481
1482                 if (success && !bitmap->mddev->degraded &&
1483                     bitmap->events_cleared < bitmap->mddev->events) {
1484                         bitmap->events_cleared = bitmap->mddev->events;
1485                         bitmap->need_sync = 1;
1486                         sysfs_notify_dirent_safe(bitmap->sysfs_can_clear);
1487                 }
1488
1489                 if (!success && !NEEDED(*bmc))
1490                         *bmc |= NEEDED_MASK;
1491
1492                 if (COUNTER(*bmc) == COUNTER_MAX)
1493                         wake_up(&bitmap->overflow_wait);
1494
1495                 (*bmc)--;
1496                 if (*bmc <= 2) {
1497                         bitmap_set_pending(&bitmap->counts, offset);
1498                         bitmap->allclean = 0;
1499                 }
1500                 spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1501                 offset += blocks;
1502                 if (sectors > blocks)
1503                         sectors -= blocks;
1504                 else
1505                         sectors = 0;
1506         }
1507 }
1508 EXPORT_SYMBOL(bitmap_endwrite);
1509
1510 static int __bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1511                                int degraded)
1512 {
1513         bitmap_counter_t *bmc;
1514         int rv;
1515         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1516                 *blocks = 1024;
1517                 return 1; /* always resync if no bitmap */
1518         }
1519         spin_lock_irq(&bitmap->counts.lock);
1520         bmc = bitmap_get_counter(&bitmap->counts, offset, blocks, 0);
1521         rv = 0;
1522         if (bmc) {
1523                 /* locked */
1524                 if (RESYNC(*bmc))
1525                         rv = 1;
1526                 else if (NEEDED(*bmc)) {
1527                         rv = 1;
1528                         if (!degraded) { /* don't set/clear bits if degraded */
1529                                 *bmc |= RESYNC_MASK;
1530                                 *bmc &= ~NEEDED_MASK;
1531                         }
1532                 }
1533         }
1534         spin_unlock_irq(&bitmap->counts.lock);
1535         return rv;
1536 }
1537
1538 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1539                       int degraded)
1540 {
1541         /* bitmap_start_sync must always report on multiples of whole
1542          * pages, otherwise resync (which is very PAGE_SIZE based) will
1543          * get confused.
1544          * So call __bitmap_start_sync repeatedly (if needed) until
1545          * At least PAGE_SIZE>>9 blocks are covered.
1546          * Return the 'or' of the result.
1547          */
1548         int rv = 0;
1549         sector_t blocks1;
1550
1551         *blocks = 0;
1552         while (*blocks < (PAGE_SIZE>>9)) {
1553                 rv |= __bitmap_start_sync(bitmap, offset,
1554                                           &blocks1, degraded);
1555                 offset += blocks1;
1556                 *blocks += blocks1;
1557         }
1558         return rv;
1559 }
1560 EXPORT_SYMBOL(bitmap_start_sync);
1561
1562 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks, int aborted)
1563 {
1564         bitmap_counter_t *bmc;
1565         unsigned long flags;
1566
1567         if (bitmap == NULL) {
1568                 *blocks = 1024;
1569                 return;
1570         }
1571         spin_lock_irqsave(&bitmap->counts.lock, flags);
1572         bmc = bitmap_get_counter(&bitmap->counts, offset, blocks, 0);
1573         if (bmc == NULL)
1574                 goto unlock;
1575         /* locked */
1576         if (RESYNC(*bmc)) {
1577                 *bmc &= ~RESYNC_MASK;
1578
1579                 if (!NEEDED(*bmc) && aborted)
1580                         *bmc |= NEEDED_MASK;
1581                 else {
1582                         if (*bmc <= 2) {
1583                                 bitmap_set_pending(&bitmap->counts, offset);
1584                                 bitmap->allclean = 0;
1585                         }
1586                 }
1587         }
1588  unlock:
1589         spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1590 }
1591 EXPORT_SYMBOL(bitmap_end_sync);
1592
1593 void bitmap_close_sync(struct bitmap *bitmap)
1594 {
1595         /* Sync has finished, and any bitmap chunks that weren't synced
1596          * properly have been aborted.  It remains to us to clear the
1597          * RESYNC bit wherever it is still on
1598          */
1599         sector_t sector = 0;
1600         sector_t blocks;
1601         if (!bitmap)
1602                 return;
1603         while (sector < bitmap->mddev->resync_max_sectors) {
1604                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1605                 sector += blocks;
1606         }
1607 }
1608 EXPORT_SYMBOL(bitmap_close_sync);
1609
1610 void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector, bool force)
1611 {
1612         sector_t s = 0;
1613         sector_t blocks;
1614
1615         if (!bitmap)
1616                 return;
1617         if (sector == 0) {
1618                 bitmap->last_end_sync = jiffies;
1619                 return;
1620         }
1621         if (!force && time_before(jiffies, (bitmap->last_end_sync
1622                                   + bitmap->mddev->bitmap_info.daemon_sleep)))
1623                 return;
1624         wait_event(bitmap->mddev->recovery_wait,
1625                    atomic_read(&bitmap->mddev->recovery_active) == 0);
1626
1627         bitmap->mddev->curr_resync_completed = sector;
1628         set_bit(MD_SB_CHANGE_CLEAN, &bitmap->mddev->sb_flags);
1629         sector &= ~((1ULL << bitmap->counts.chunkshift) - 1);
1630         s = 0;
1631         while (s < sector && s < bitmap->mddev->resync_max_sectors) {
1632                 bitmap_end_sync(bitmap, s, &blocks, 0);
1633                 s += blocks;
1634         }
1635         bitmap->last_end_sync = jiffies;
1636         sysfs_notify(&bitmap->mddev->kobj, NULL, "sync_completed");
1637 }
1638 EXPORT_SYMBOL(bitmap_cond_end_sync);
1639
1640 void bitmap_sync_with_cluster(struct mddev *mddev,
1641                               sector_t old_lo, sector_t old_hi,
1642                               sector_t new_lo, sector_t new_hi)
1643 {
1644         struct bitmap *bitmap = mddev->bitmap;
1645         sector_t sector, blocks = 0;
1646
1647         for (sector = old_lo; sector < new_lo; ) {
1648                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1649                 sector += blocks;
1650         }
1651         WARN((blocks > new_lo) && old_lo, "alignment is not correct for lo\n");
1652
1653         for (sector = old_hi; sector < new_hi; ) {
1654                 bitmap_start_sync(bitmap, sector, &blocks, 0);
1655                 sector += blocks;
1656         }
1657         WARN((blocks > new_hi) && old_hi, "alignment is not correct for hi\n");
1658 }
1659 EXPORT_SYMBOL(bitmap_sync_with_cluster);
1660
1661 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1662 {
1663         /* For each chunk covered by any of these sectors, set the
1664          * counter to 2 and possibly set resync_needed.  They should all
1665          * be 0 at this point
1666          */
1667
1668         sector_t secs;
1669         bitmap_counter_t *bmc;
1670         spin_lock_irq(&bitmap->counts.lock);
1671         bmc = bitmap_get_counter(&bitmap->counts, offset, &secs, 1);
1672         if (!bmc) {
1673                 spin_unlock_irq(&bitmap->counts.lock);
1674                 return;
1675         }
1676         if (!*bmc) {
1677                 *bmc = 2;
1678                 bitmap_count_page(&bitmap->counts, offset, 1);
1679                 bitmap_set_pending(&bitmap->counts, offset);
1680                 bitmap->allclean = 0;
1681         }
1682         if (needed)
1683                 *bmc |= NEEDED_MASK;
1684         spin_unlock_irq(&bitmap->counts.lock);
1685 }
1686
1687 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
1688 void bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1689 {
1690         unsigned long chunk;
1691
1692         for (chunk = s; chunk <= e; chunk++) {
1693                 sector_t sec = (sector_t)chunk << bitmap->counts.chunkshift;
1694                 bitmap_set_memory_bits(bitmap, sec, 1);
1695                 bitmap_file_set_bit(bitmap, sec);
1696                 if (sec < bitmap->mddev->recovery_cp)
1697                         /* We are asserting that the array is dirty,
1698                          * so move the recovery_cp address back so
1699                          * that it is obvious that it is dirty
1700                          */
1701                         bitmap->mddev->recovery_cp = sec;
1702         }
1703 }
1704
1705 /*
1706  * flush out any pending updates
1707  */
1708 void bitmap_flush(struct mddev *mddev)
1709 {
1710         struct bitmap *bitmap = mddev->bitmap;
1711         long sleep;
1712
1713         if (!bitmap) /* there was no bitmap */
1714                 return;
1715
1716         /* run the daemon_work three time to ensure everything is flushed
1717          * that can be
1718          */
1719         sleep = mddev->bitmap_info.daemon_sleep * 2;
1720         bitmap->daemon_lastrun -= sleep;
1721         bitmap_daemon_work(mddev);
1722         bitmap->daemon_lastrun -= sleep;
1723         bitmap_daemon_work(mddev);
1724         bitmap->daemon_lastrun -= sleep;
1725         bitmap_daemon_work(mddev);
1726         bitmap_update_sb(bitmap);
1727 }
1728
1729 /*
1730  * free memory that was allocated
1731  */
1732 void bitmap_free(struct bitmap *bitmap)
1733 {
1734         unsigned long k, pages;
1735         struct bitmap_page *bp;
1736
1737         if (!bitmap) /* there was no bitmap */
1738                 return;
1739
1740         if (bitmap->sysfs_can_clear)
1741                 sysfs_put(bitmap->sysfs_can_clear);
1742
1743         if (mddev_is_clustered(bitmap->mddev) && bitmap->mddev->cluster_info &&
1744                 bitmap->cluster_slot == md_cluster_ops->slot_number(bitmap->mddev))
1745                 md_cluster_stop(bitmap->mddev);
1746
1747         /* Shouldn't be needed - but just in case.... */
1748         wait_event(bitmap->write_wait,
1749                    atomic_read(&bitmap->pending_writes) == 0);
1750
1751         /* release the bitmap file  */
1752         bitmap_file_unmap(&bitmap->storage);
1753
1754         bp = bitmap->counts.bp;
1755         pages = bitmap->counts.pages;
1756
1757         /* free all allocated memory */
1758
1759         if (bp) /* deallocate the page memory */
1760                 for (k = 0; k < pages; k++)
1761                         if (bp[k].map && !bp[k].hijacked)
1762                                 kfree(bp[k].map);
1763         kfree(bp);
1764         kfree(bitmap);
1765 }
1766 EXPORT_SYMBOL(bitmap_free);
1767
1768 void bitmap_wait_behind_writes(struct mddev *mddev)
1769 {
1770         struct bitmap *bitmap = mddev->bitmap;
1771
1772         /* wait for behind writes to complete */
1773         if (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
1774                 pr_debug("md:%s: behind writes in progress - waiting to stop.\n",
1775                          mdname(mddev));
1776                 /* need to kick something here to make sure I/O goes? */
1777                 wait_event(bitmap->behind_wait,
1778                            atomic_read(&bitmap->behind_writes) == 0);
1779         }
1780 }
1781
1782 void bitmap_destroy(struct mddev *mddev)
1783 {
1784         struct bitmap *bitmap = mddev->bitmap;
1785
1786         if (!bitmap) /* there was no bitmap */
1787                 return;
1788
1789         bitmap_wait_behind_writes(mddev);
1790
1791         mutex_lock(&mddev->bitmap_info.mutex);
1792         spin_lock(&mddev->lock);
1793         mddev->bitmap = NULL; /* disconnect from the md device */
1794         spin_unlock(&mddev->lock);
1795         mutex_unlock(&mddev->bitmap_info.mutex);
1796         if (mddev->thread)
1797                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1798
1799         bitmap_free(bitmap);
1800 }
1801
1802 /*
1803  * initialize the bitmap structure
1804  * if this returns an error, bitmap_destroy must be called to do clean up
1805  * once mddev->bitmap is set
1806  */
1807 struct bitmap *bitmap_create(struct mddev *mddev, int slot)
1808 {
1809         struct bitmap *bitmap;
1810         sector_t blocks = mddev->resync_max_sectors;
1811         struct file *file = mddev->bitmap_info.file;
1812         int err;
1813         struct kernfs_node *bm = NULL;
1814
1815         BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
1816
1817         BUG_ON(file && mddev->bitmap_info.offset);
1818
1819         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1820         if (!bitmap)
1821                 return ERR_PTR(-ENOMEM);
1822
1823         spin_lock_init(&bitmap->counts.lock);
1824         atomic_set(&bitmap->pending_writes, 0);
1825         init_waitqueue_head(&bitmap->write_wait);
1826         init_waitqueue_head(&bitmap->overflow_wait);
1827         init_waitqueue_head(&bitmap->behind_wait);
1828
1829         bitmap->mddev = mddev;
1830         bitmap->cluster_slot = slot;
1831
1832         if (mddev->kobj.sd)
1833                 bm = sysfs_get_dirent(mddev->kobj.sd, "bitmap");
1834         if (bm) {
1835                 bitmap->sysfs_can_clear = sysfs_get_dirent(bm, "can_clear");
1836                 sysfs_put(bm);
1837         } else
1838                 bitmap->sysfs_can_clear = NULL;
1839
1840         bitmap->storage.file = file;
1841         if (file) {
1842                 get_file(file);
1843                 /* As future accesses to this file will use bmap,
1844                  * and bypass the page cache, we must sync the file
1845                  * first.
1846                  */
1847                 vfs_fsync(file, 1);
1848         }
1849         /* read superblock from bitmap file (this sets mddev->bitmap_info.chunksize) */
1850         if (!mddev->bitmap_info.external) {
1851                 /*
1852                  * If 'MD_ARRAY_FIRST_USE' is set, then device-mapper is
1853                  * instructing us to create a new on-disk bitmap instance.
1854                  */
1855                 if (test_and_clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags))
1856                         err = bitmap_new_disk_sb(bitmap);
1857                 else
1858                         err = bitmap_read_sb(bitmap);
1859         } else {
1860                 err = 0;
1861                 if (mddev->bitmap_info.chunksize == 0 ||
1862                     mddev->bitmap_info.daemon_sleep == 0)
1863                         /* chunksize and time_base need to be
1864                          * set first. */
1865                         err = -EINVAL;
1866         }
1867         if (err)
1868                 goto error;
1869
1870         bitmap->daemon_lastrun = jiffies;
1871         err = bitmap_resize(bitmap, blocks, mddev->bitmap_info.chunksize, 1);
1872         if (err)
1873                 goto error;
1874
1875         pr_debug("created bitmap (%lu pages) for device %s\n",
1876                  bitmap->counts.pages, bmname(bitmap));
1877
1878         err = test_bit(BITMAP_WRITE_ERROR, &bitmap->flags) ? -EIO : 0;
1879         if (err)
1880                 goto error;
1881
1882         return bitmap;
1883  error:
1884         bitmap_free(bitmap);
1885         return ERR_PTR(err);
1886 }
1887
1888 int bitmap_load(struct mddev *mddev)
1889 {
1890         int err = 0;
1891         sector_t start = 0;
1892         sector_t sector = 0;
1893         struct bitmap *bitmap = mddev->bitmap;
1894
1895         if (!bitmap)
1896                 goto out;
1897
1898         if (mddev_is_clustered(mddev))
1899                 md_cluster_ops->load_bitmaps(mddev, mddev->bitmap_info.nodes);
1900
1901         /* Clear out old bitmap info first:  Either there is none, or we
1902          * are resuming after someone else has possibly changed things,
1903          * so we should forget old cached info.
1904          * All chunks should be clean, but some might need_sync.
1905          */
1906         while (sector < mddev->resync_max_sectors) {
1907                 sector_t blocks;
1908                 bitmap_start_sync(bitmap, sector, &blocks, 0);
1909                 sector += blocks;
1910         }
1911         bitmap_close_sync(bitmap);
1912
1913         if (mddev->degraded == 0
1914             || bitmap->events_cleared == mddev->events)
1915                 /* no need to keep dirty bits to optimise a
1916                  * re-add of a missing device */
1917                 start = mddev->recovery_cp;
1918
1919         mutex_lock(&mddev->bitmap_info.mutex);
1920         err = bitmap_init_from_disk(bitmap, start);
1921         mutex_unlock(&mddev->bitmap_info.mutex);
1922
1923         if (err)
1924                 goto out;
1925         clear_bit(BITMAP_STALE, &bitmap->flags);
1926
1927         /* Kick recovery in case any bits were set */
1928         set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
1929
1930         mddev->thread->timeout = mddev->bitmap_info.daemon_sleep;
1931         md_wakeup_thread(mddev->thread);
1932
1933         bitmap_update_sb(bitmap);
1934
1935         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
1936                 err = -EIO;
1937 out:
1938         return err;
1939 }
1940 EXPORT_SYMBOL_GPL(bitmap_load);
1941
1942 struct bitmap *get_bitmap_from_slot(struct mddev *mddev, int slot)
1943 {
1944         int rv = 0;
1945         struct bitmap *bitmap;
1946
1947         bitmap = bitmap_create(mddev, slot);
1948         if (IS_ERR(bitmap)) {
1949                 rv = PTR_ERR(bitmap);
1950                 return ERR_PTR(rv);
1951         }
1952
1953         rv = bitmap_init_from_disk(bitmap, 0);
1954         if (rv) {
1955                 bitmap_free(bitmap);
1956                 return ERR_PTR(rv);
1957         }
1958
1959         return bitmap;
1960 }
1961 EXPORT_SYMBOL(get_bitmap_from_slot);
1962
1963 /* Loads the bitmap associated with slot and copies the resync information
1964  * to our bitmap
1965  */
1966 int bitmap_copy_from_slot(struct mddev *mddev, int slot,
1967                 sector_t *low, sector_t *high, bool clear_bits)
1968 {
1969         int rv = 0, i, j;
1970         sector_t block, lo = 0, hi = 0;
1971         struct bitmap_counts *counts;
1972         struct bitmap *bitmap;
1973
1974         bitmap = get_bitmap_from_slot(mddev, slot);
1975         if (IS_ERR(bitmap)) {
1976                 pr_err("%s can't get bitmap from slot %d\n", __func__, slot);
1977                 return -1;
1978         }
1979
1980         counts = &bitmap->counts;
1981         for (j = 0; j < counts->chunks; j++) {
1982                 block = (sector_t)j << counts->chunkshift;
1983                 if (bitmap_file_test_bit(bitmap, block)) {
1984                         if (!lo)
1985                                 lo = block;
1986                         hi = block;
1987                         bitmap_file_clear_bit(bitmap, block);
1988                         bitmap_set_memory_bits(mddev->bitmap, block, 1);
1989                         bitmap_file_set_bit(mddev->bitmap, block);
1990                 }
1991         }
1992
1993         if (clear_bits) {
1994                 bitmap_update_sb(bitmap);
1995                 /* BITMAP_PAGE_PENDING is set, but bitmap_unplug needs
1996                  * BITMAP_PAGE_DIRTY or _NEEDWRITE to write ... */
1997                 for (i = 0; i < bitmap->storage.file_pages; i++)
1998                         if (test_page_attr(bitmap, i, BITMAP_PAGE_PENDING))
1999                                 set_page_attr(bitmap, i, BITMAP_PAGE_NEEDWRITE);
2000                 bitmap_unplug(bitmap);
2001         }
2002         bitmap_unplug(mddev->bitmap);
2003         *low = lo;
2004         *high = hi;
2005
2006         return rv;
2007 }
2008 EXPORT_SYMBOL_GPL(bitmap_copy_from_slot);
2009
2010
2011 void bitmap_status(struct seq_file *seq, struct bitmap *bitmap)
2012 {
2013         unsigned long chunk_kb;
2014         struct bitmap_counts *counts;
2015
2016         if (!bitmap)
2017                 return;
2018
2019         counts = &bitmap->counts;
2020
2021         chunk_kb = bitmap->mddev->bitmap_info.chunksize >> 10;
2022         seq_printf(seq, "bitmap: %lu/%lu pages [%luKB], "
2023                    "%lu%s chunk",
2024                    counts->pages - counts->missing_pages,
2025                    counts->pages,
2026                    (counts->pages - counts->missing_pages)
2027                    << (PAGE_SHIFT - 10),
2028                    chunk_kb ? chunk_kb : bitmap->mddev->bitmap_info.chunksize,
2029                    chunk_kb ? "KB" : "B");
2030         if (bitmap->storage.file) {
2031                 seq_printf(seq, ", file: ");
2032                 seq_file_path(seq, bitmap->storage.file, " \t\n");
2033         }
2034
2035         seq_printf(seq, "\n");
2036 }
2037
2038 int bitmap_resize(struct bitmap *bitmap, sector_t blocks,
2039                   int chunksize, int init)
2040 {
2041         /* If chunk_size is 0, choose an appropriate chunk size.
2042          * Then possibly allocate new storage space.
2043          * Then quiesce, copy bits, replace bitmap, and re-start
2044          *
2045          * This function is called both to set up the initial bitmap
2046          * and to resize the bitmap while the array is active.
2047          * If this happens as a result of the array being resized,
2048          * chunksize will be zero, and we need to choose a suitable
2049          * chunksize, otherwise we use what we are given.
2050          */
2051         struct bitmap_storage store;
2052         struct bitmap_counts old_counts;
2053         unsigned long chunks;
2054         sector_t block;
2055         sector_t old_blocks, new_blocks;
2056         int chunkshift;
2057         int ret = 0;
2058         long pages;
2059         struct bitmap_page *new_bp;
2060
2061         if (chunksize == 0) {
2062                 /* If there is enough space, leave the chunk size unchanged,
2063                  * else increase by factor of two until there is enough space.
2064                  */
2065                 long bytes;
2066                 long space = bitmap->mddev->bitmap_info.space;
2067
2068                 if (space == 0) {
2069                         /* We don't know how much space there is, so limit
2070                          * to current size - in sectors.
2071                          */
2072                         bytes = DIV_ROUND_UP(bitmap->counts.chunks, 8);
2073                         if (!bitmap->mddev->bitmap_info.external)
2074                                 bytes += sizeof(bitmap_super_t);
2075                         space = DIV_ROUND_UP(bytes, 512);
2076                         bitmap->mddev->bitmap_info.space = space;
2077                 }
2078                 chunkshift = bitmap->counts.chunkshift;
2079                 chunkshift--;
2080                 do {
2081                         /* 'chunkshift' is shift from block size to chunk size */
2082                         chunkshift++;
2083                         chunks = DIV_ROUND_UP_SECTOR_T(blocks, 1 << chunkshift);
2084                         bytes = DIV_ROUND_UP(chunks, 8);
2085                         if (!bitmap->mddev->bitmap_info.external)
2086                                 bytes += sizeof(bitmap_super_t);
2087                 } while (bytes > (space << 9));
2088         } else
2089                 chunkshift = ffz(~chunksize) - BITMAP_BLOCK_SHIFT;
2090
2091         chunks = DIV_ROUND_UP_SECTOR_T(blocks, 1 << chunkshift);
2092         memset(&store, 0, sizeof(store));
2093         if (bitmap->mddev->bitmap_info.offset || bitmap->mddev->bitmap_info.file)
2094                 ret = bitmap_storage_alloc(&store, chunks,
2095                                            !bitmap->mddev->bitmap_info.external,
2096                                            mddev_is_clustered(bitmap->mddev)
2097                                            ? bitmap->cluster_slot : 0);
2098         if (ret) {
2099                 bitmap_file_unmap(&store);
2100                 goto err;
2101         }
2102
2103         pages = DIV_ROUND_UP(chunks, PAGE_COUNTER_RATIO);
2104
2105         new_bp = kzalloc(pages * sizeof(*new_bp), GFP_KERNEL);
2106         ret = -ENOMEM;
2107         if (!new_bp) {
2108                 bitmap_file_unmap(&store);
2109                 goto err;
2110         }
2111
2112         if (!init)
2113                 bitmap->mddev->pers->quiesce(bitmap->mddev, 1);
2114
2115         store.file = bitmap->storage.file;
2116         bitmap->storage.file = NULL;
2117
2118         if (store.sb_page && bitmap->storage.sb_page)
2119                 memcpy(page_address(store.sb_page),
2120                        page_address(bitmap->storage.sb_page),
2121                        sizeof(bitmap_super_t));
2122         bitmap_file_unmap(&bitmap->storage);
2123         bitmap->storage = store;
2124
2125         old_counts = bitmap->counts;
2126         bitmap->counts.bp = new_bp;
2127         bitmap->counts.pages = pages;
2128         bitmap->counts.missing_pages = pages;
2129         bitmap->counts.chunkshift = chunkshift;
2130         bitmap->counts.chunks = chunks;
2131         bitmap->mddev->bitmap_info.chunksize = 1 << (chunkshift +
2132                                                      BITMAP_BLOCK_SHIFT);
2133
2134         blocks = min(old_counts.chunks << old_counts.chunkshift,
2135                      chunks << chunkshift);
2136
2137         spin_lock_irq(&bitmap->counts.lock);
2138         /* For cluster raid, need to pre-allocate bitmap */
2139         if (mddev_is_clustered(bitmap->mddev)) {
2140                 unsigned long page;
2141                 for (page = 0; page < pages; page++) {
2142                         ret = bitmap_checkpage(&bitmap->counts, page, 1, 1);
2143                         if (ret) {
2144                                 unsigned long k;
2145
2146                                 /* deallocate the page memory */
2147                                 for (k = 0; k < page; k++) {
2148                                         kfree(new_bp[k].map);
2149                                 }
2150
2151                                 /* restore some fields from old_counts */
2152                                 bitmap->counts.bp = old_counts.bp;
2153                                 bitmap->counts.pages = old_counts.pages;
2154                                 bitmap->counts.missing_pages = old_counts.pages;
2155                                 bitmap->counts.chunkshift = old_counts.chunkshift;
2156                                 bitmap->counts.chunks = old_counts.chunks;
2157                                 bitmap->mddev->bitmap_info.chunksize = 1 << (old_counts.chunkshift +
2158                                                                              BITMAP_BLOCK_SHIFT);
2159                                 blocks = old_counts.chunks << old_counts.chunkshift;
2160                                 pr_warn("Could not pre-allocate in-memory bitmap for cluster raid\n");
2161                                 break;
2162                         } else
2163                                 bitmap->counts.bp[page].count += 1;
2164                 }
2165         }
2166
2167         for (block = 0; block < blocks; ) {
2168                 bitmap_counter_t *bmc_old, *bmc_new;
2169                 int set;
2170
2171                 bmc_old = bitmap_get_counter(&old_counts, block,
2172                                              &old_blocks, 0);
2173                 set = bmc_old && NEEDED(*bmc_old);
2174
2175                 if (set) {
2176                         bmc_new = bitmap_get_counter(&bitmap->counts, block,
2177                                                      &new_blocks, 1);
2178                         if (*bmc_new == 0) {
2179                                 /* need to set on-disk bits too. */
2180                                 sector_t end = block + new_blocks;
2181                                 sector_t start = block >> chunkshift;
2182                                 start <<= chunkshift;
2183                                 while (start < end) {
2184                                         bitmap_file_set_bit(bitmap, block);
2185                                         start += 1 << chunkshift;
2186                                 }
2187                                 *bmc_new = 2;
2188                                 bitmap_count_page(&bitmap->counts,
2189                                                   block, 1);
2190                                 bitmap_set_pending(&bitmap->counts,
2191                                                    block);
2192                         }
2193                         *bmc_new |= NEEDED_MASK;
2194                         if (new_blocks < old_blocks)
2195                                 old_blocks = new_blocks;
2196                 }
2197                 block += old_blocks;
2198         }
2199
2200         if (!init) {
2201                 int i;
2202                 while (block < (chunks << chunkshift)) {
2203                         bitmap_counter_t *bmc;
2204                         bmc = bitmap_get_counter(&bitmap->counts, block,
2205                                                  &new_blocks, 1);
2206                         if (bmc) {
2207                                 /* new space.  It needs to be resynced, so
2208                                  * we set NEEDED_MASK.
2209                                  */
2210                                 if (*bmc == 0) {
2211                                         *bmc = NEEDED_MASK | 2;
2212                                         bitmap_count_page(&bitmap->counts,
2213                                                           block, 1);
2214                                         bitmap_set_pending(&bitmap->counts,
2215                                                            block);
2216                                 }
2217                         }
2218                         block += new_blocks;
2219                 }
2220                 for (i = 0; i < bitmap->storage.file_pages; i++)
2221                         set_page_attr(bitmap, i, BITMAP_PAGE_DIRTY);
2222         }
2223         spin_unlock_irq(&bitmap->counts.lock);
2224
2225         if (!init) {
2226                 bitmap_unplug(bitmap);
2227                 bitmap->mddev->pers->quiesce(bitmap->mddev, 0);
2228         }
2229         ret = 0;
2230 err:
2231         return ret;
2232 }
2233 EXPORT_SYMBOL_GPL(bitmap_resize);
2234
2235 static ssize_t
2236 location_show(struct mddev *mddev, char *page)
2237 {
2238         ssize_t len;
2239         if (mddev->bitmap_info.file)
2240                 len = sprintf(page, "file");
2241         else if (mddev->bitmap_info.offset)
2242                 len = sprintf(page, "%+lld", (long long)mddev->bitmap_info.offset);
2243         else
2244                 len = sprintf(page, "none");
2245         len += sprintf(page+len, "\n");
2246         return len;
2247 }
2248
2249 static ssize_t
2250 location_store(struct mddev *mddev, const char *buf, size_t len)
2251 {
2252         int rv;
2253
2254         rv = mddev_lock(mddev);
2255         if (rv)
2256                 return rv;
2257         if (mddev->pers) {
2258                 if (!mddev->pers->quiesce) {
2259                         rv = -EBUSY;
2260                         goto out;
2261                 }
2262                 if (mddev->recovery || mddev->sync_thread) {
2263                         rv = -EBUSY;
2264                         goto out;
2265                 }
2266         }
2267
2268         if (mddev->bitmap || mddev->bitmap_info.file ||
2269             mddev->bitmap_info.offset) {
2270                 /* bitmap already configured.  Only option is to clear it */
2271                 if (strncmp(buf, "none", 4) != 0) {
2272                         rv = -EBUSY;
2273                         goto out;
2274                 }
2275                 if (mddev->pers) {
2276                         mddev->pers->quiesce(mddev, 1);
2277                         bitmap_destroy(mddev);
2278                         mddev->pers->quiesce(mddev, 0);
2279                 }
2280                 mddev->bitmap_info.offset = 0;
2281                 if (mddev->bitmap_info.file) {
2282                         struct file *f = mddev->bitmap_info.file;
2283                         mddev->bitmap_info.file = NULL;
2284                         fput(f);
2285                 }
2286         } else {
2287                 /* No bitmap, OK to set a location */
2288                 long long offset;
2289                 if (strncmp(buf, "none", 4) == 0)
2290                         /* nothing to be done */;
2291                 else if (strncmp(buf, "file:", 5) == 0) {
2292                         /* Not supported yet */
2293                         rv = -EINVAL;
2294                         goto out;
2295                 } else {
2296                         if (buf[0] == '+')
2297                                 rv = kstrtoll(buf+1, 10, &offset);
2298                         else
2299                                 rv = kstrtoll(buf, 10, &offset);
2300                         if (rv)
2301                                 goto out;
2302                         if (offset == 0) {
2303                                 rv = -EINVAL;
2304                                 goto out;
2305                         }
2306                         if (mddev->bitmap_info.external == 0 &&
2307                             mddev->major_version == 0 &&
2308                             offset != mddev->bitmap_info.default_offset) {
2309                                 rv = -EINVAL;
2310                                 goto out;
2311                         }
2312                         mddev->bitmap_info.offset = offset;
2313                         if (mddev->pers) {
2314                                 struct bitmap *bitmap;
2315                                 mddev->pers->quiesce(mddev, 1);
2316                                 bitmap = bitmap_create(mddev, -1);
2317                                 if (IS_ERR(bitmap))
2318                                         rv = PTR_ERR(bitmap);
2319                                 else {
2320                                         mddev->bitmap = bitmap;
2321                                         rv = bitmap_load(mddev);
2322                                         if (rv)
2323                                                 mddev->bitmap_info.offset = 0;
2324                                 }
2325                                 mddev->pers->quiesce(mddev, 0);
2326                                 if (rv) {
2327                                         bitmap_destroy(mddev);
2328                                         goto out;
2329                                 }
2330                         }
2331                 }
2332         }
2333         if (!mddev->external) {
2334                 /* Ensure new bitmap info is stored in
2335                  * metadata promptly.
2336                  */
2337                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
2338                 md_wakeup_thread(mddev->thread);
2339         }
2340         rv = 0;
2341 out:
2342         mddev_unlock(mddev);
2343         if (rv)
2344                 return rv;
2345         return len;
2346 }
2347
2348 static struct md_sysfs_entry bitmap_location =
2349 __ATTR(location, S_IRUGO|S_IWUSR, location_show, location_store);
2350
2351 /* 'bitmap/space' is the space available at 'location' for the
2352  * bitmap.  This allows the kernel to know when it is safe to
2353  * resize the bitmap to match a resized array.
2354  */
2355 static ssize_t
2356 space_show(struct mddev *mddev, char *page)
2357 {
2358         return sprintf(page, "%lu\n", mddev->bitmap_info.space);
2359 }
2360
2361 static ssize_t
2362 space_store(struct mddev *mddev, const char *buf, size_t len)
2363 {
2364         unsigned long sectors;
2365         int rv;
2366
2367         rv = kstrtoul(buf, 10, &sectors);
2368         if (rv)
2369                 return rv;
2370
2371         if (sectors == 0)
2372                 return -EINVAL;
2373
2374         if (mddev->bitmap &&
2375             sectors < (mddev->bitmap->storage.bytes + 511) >> 9)
2376                 return -EFBIG; /* Bitmap is too big for this small space */
2377
2378         /* could make sure it isn't too big, but that isn't really
2379          * needed - user-space should be careful.
2380          */
2381         mddev->bitmap_info.space = sectors;
2382         return len;
2383 }
2384
2385 static struct md_sysfs_entry bitmap_space =
2386 __ATTR(space, S_IRUGO|S_IWUSR, space_show, space_store);
2387
2388 static ssize_t
2389 timeout_show(struct mddev *mddev, char *page)
2390 {
2391         ssize_t len;
2392         unsigned long secs = mddev->bitmap_info.daemon_sleep / HZ;
2393         unsigned long jifs = mddev->bitmap_info.daemon_sleep % HZ;
2394
2395         len = sprintf(page, "%lu", secs);
2396         if (jifs)
2397                 len += sprintf(page+len, ".%03u", jiffies_to_msecs(jifs));
2398         len += sprintf(page+len, "\n");
2399         return len;
2400 }
2401
2402 static ssize_t
2403 timeout_store(struct mddev *mddev, const char *buf, size_t len)
2404 {
2405         /* timeout can be set at any time */
2406         unsigned long timeout;
2407         int rv = strict_strtoul_scaled(buf, &timeout, 4);
2408         if (rv)
2409                 return rv;
2410
2411         /* just to make sure we don't overflow... */
2412         if (timeout >= LONG_MAX / HZ)
2413                 return -EINVAL;
2414
2415         timeout = timeout * HZ / 10000;
2416
2417         if (timeout >= MAX_SCHEDULE_TIMEOUT)
2418                 timeout = MAX_SCHEDULE_TIMEOUT-1;
2419         if (timeout < 1)
2420                 timeout = 1;
2421         mddev->bitmap_info.daemon_sleep = timeout;
2422         if (mddev->thread) {
2423                 /* if thread->timeout is MAX_SCHEDULE_TIMEOUT, then
2424                  * the bitmap is all clean and we don't need to
2425                  * adjust the timeout right now
2426                  */
2427                 if (mddev->thread->timeout < MAX_SCHEDULE_TIMEOUT) {
2428                         mddev->thread->timeout = timeout;
2429                         md_wakeup_thread(mddev->thread);
2430                 }
2431         }
2432         return len;
2433 }
2434
2435 static struct md_sysfs_entry bitmap_timeout =
2436 __ATTR(time_base, S_IRUGO|S_IWUSR, timeout_show, timeout_store);
2437
2438 static ssize_t
2439 backlog_show(struct mddev *mddev, char *page)
2440 {
2441         return sprintf(page, "%lu\n", mddev->bitmap_info.max_write_behind);
2442 }
2443
2444 static ssize_t
2445 backlog_store(struct mddev *mddev, const char *buf, size_t len)
2446 {
2447         unsigned long backlog;
2448         int rv = kstrtoul(buf, 10, &backlog);
2449         if (rv)
2450                 return rv;
2451         if (backlog > COUNTER_MAX)
2452                 return -EINVAL;
2453         mddev->bitmap_info.max_write_behind = backlog;
2454         return len;
2455 }
2456
2457 static struct md_sysfs_entry bitmap_backlog =
2458 __ATTR(backlog, S_IRUGO|S_IWUSR, backlog_show, backlog_store);
2459
2460 static ssize_t
2461 chunksize_show(struct mddev *mddev, char *page)
2462 {
2463         return sprintf(page, "%lu\n", mddev->bitmap_info.chunksize);
2464 }
2465
2466 static ssize_t
2467 chunksize_store(struct mddev *mddev, const char *buf, size_t len)
2468 {
2469         /* Can only be changed when no bitmap is active */
2470         int rv;
2471         unsigned long csize;
2472         if (mddev->bitmap)
2473                 return -EBUSY;
2474         rv = kstrtoul(buf, 10, &csize);
2475         if (rv)
2476                 return rv;
2477         if (csize < 512 ||
2478             !is_power_of_2(csize))
2479                 return -EINVAL;
2480         mddev->bitmap_info.chunksize = csize;
2481         return len;
2482 }
2483
2484 static struct md_sysfs_entry bitmap_chunksize =
2485 __ATTR(chunksize, S_IRUGO|S_IWUSR, chunksize_show, chunksize_store);
2486
2487 static ssize_t metadata_show(struct mddev *mddev, char *page)
2488 {
2489         if (mddev_is_clustered(mddev))
2490                 return sprintf(page, "clustered\n");
2491         return sprintf(page, "%s\n", (mddev->bitmap_info.external
2492                                       ? "external" : "internal"));
2493 }
2494
2495 static ssize_t metadata_store(struct mddev *mddev, const char *buf, size_t len)
2496 {
2497         if (mddev->bitmap ||
2498             mddev->bitmap_info.file ||
2499             mddev->bitmap_info.offset)
2500                 return -EBUSY;
2501         if (strncmp(buf, "external", 8) == 0)
2502                 mddev->bitmap_info.external = 1;
2503         else if ((strncmp(buf, "internal", 8) == 0) ||
2504                         (strncmp(buf, "clustered", 9) == 0))
2505                 mddev->bitmap_info.external = 0;
2506         else
2507                 return -EINVAL;
2508         return len;
2509 }
2510
2511 static struct md_sysfs_entry bitmap_metadata =
2512 __ATTR(metadata, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
2513
2514 static ssize_t can_clear_show(struct mddev *mddev, char *page)
2515 {
2516         int len;
2517         spin_lock(&mddev->lock);
2518         if (mddev->bitmap)
2519                 len = sprintf(page, "%s\n", (mddev->bitmap->need_sync ?
2520                                              "false" : "true"));
2521         else
2522                 len = sprintf(page, "\n");
2523         spin_unlock(&mddev->lock);
2524         return len;
2525 }
2526
2527 static ssize_t can_clear_store(struct mddev *mddev, const char *buf, size_t len)
2528 {
2529         if (mddev->bitmap == NULL)
2530                 return -ENOENT;
2531         if (strncmp(buf, "false", 5) == 0)
2532                 mddev->bitmap->need_sync = 1;
2533         else if (strncmp(buf, "true", 4) == 0) {
2534                 if (mddev->degraded)
2535                         return -EBUSY;
2536                 mddev->bitmap->need_sync = 0;
2537         } else
2538                 return -EINVAL;
2539         return len;
2540 }
2541
2542 static struct md_sysfs_entry bitmap_can_clear =
2543 __ATTR(can_clear, S_IRUGO|S_IWUSR, can_clear_show, can_clear_store);
2544
2545 static ssize_t
2546 behind_writes_used_show(struct mddev *mddev, char *page)
2547 {
2548         ssize_t ret;
2549         spin_lock(&mddev->lock);
2550         if (mddev->bitmap == NULL)
2551                 ret = sprintf(page, "0\n");
2552         else
2553                 ret = sprintf(page, "%lu\n",
2554                               mddev->bitmap->behind_writes_used);
2555         spin_unlock(&mddev->lock);
2556         return ret;
2557 }
2558
2559 static ssize_t
2560 behind_writes_used_reset(struct mddev *mddev, const char *buf, size_t len)
2561 {
2562         if (mddev->bitmap)
2563                 mddev->bitmap->behind_writes_used = 0;
2564         return len;
2565 }
2566
2567 static struct md_sysfs_entry max_backlog_used =
2568 __ATTR(max_backlog_used, S_IRUGO | S_IWUSR,
2569        behind_writes_used_show, behind_writes_used_reset);
2570
2571 static struct attribute *md_bitmap_attrs[] = {
2572         &bitmap_location.attr,
2573         &bitmap_space.attr,
2574         &bitmap_timeout.attr,
2575         &bitmap_backlog.attr,
2576         &bitmap_chunksize.attr,
2577         &bitmap_metadata.attr,
2578         &bitmap_can_clear.attr,
2579         &max_backlog_used.attr,
2580         NULL
2581 };
2582 struct attribute_group md_bitmap_group = {
2583         .name = "bitmap",
2584         .attrs = md_bitmap_attrs,
2585 };
2586