drivers/md/md-bitmap.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * bitmap.c two-level bitmap (C) Peter T. Breuer (ptb@ot.uc3m.es) 2003
   4  *
   5  * bitmap_create  - sets up the bitmap structure
   6  * bitmap_destroy - destroys the bitmap structure
   7  *
   8  * additions, Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.:
   9  * - added disk storage for bitmap
  10  * - changes to allow various bitmap chunk sizes
  11  */
  12
  13 /*
  14  * Still to do:
  15  *
  16  * flush after percent set rather than just time based. (maybe both).
  17  */
  18
  19 #include <linux/blkdev.h>
  20 #include <linux/module.h>
  21 #include <linux/errno.h>
  22 #include <linux/slab.h>
  23 #include <linux/init.h>
  24 #include <linux/timer.h>
  25 #include <linux/sched.h>
  26 #include <linux/list.h>
  27 #include <linux/file.h>
  28 #include <linux/mount.h>
  29 #include <linux/buffer_head.h>
  30 #include <linux/seq_file.h>
  31 #include <trace/events/block.h>
  32 #include "md.h"
  33 #include "md-bitmap.h"
  34
  35 static inline char *bmname(struct bitmap *bitmap)
  36 {
  37         return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
  38 }
  39
  40 /*
  41  * check a page and, if necessary, allocate it (or hijack it if the alloc fails)
  42  *
  43  * 1) check to see if this page is allocated, if it's not then try to alloc
  44  * 2) if the alloc fails, set the page's hijacked flag so we'll use the
  45  *    page pointer directly as a counter
  46  *
  47  * if we find our page, we increment the page's refcount so that it stays
  48  * allocated while we're using it
  49  */
  50 static int md_bitmap_checkpage(struct bitmap_counts *bitmap,
  51                                unsigned long page, int create, int no_hijack)
  52 __releases(bitmap->lock)
  53 __acquires(bitmap->lock)
  54 {
  55         unsigned char *mappage;
  56
  57         if (page >= bitmap->pages) {
  58                 /* This can happen if bitmap_start_sync goes beyond
  59                  * End-of-device while looking for a whole page.
  60                  * It is harmless.
  61                  */
  62                 return -EINVAL;
  63         }
  64
  65         if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
  66                 return 0;
  67
  68         if (bitmap->bp[page].map) /* page is already allocated, just return */
  69                 return 0;
  70
  71         if (!create)
  72                 return -ENOENT;
  73
  74         /* this page has not been allocated yet */
  75
  76         spin_unlock_irq(&bitmap->lock);
  77         /* It is possible that this is being called inside a
  78          * prepare_to_wait/finish_wait loop from raid5c:make_request().
  79          * In general it is not permitted to sleep in that context as it
  80          * can cause the loop to spin freely.
  81          * That doesn't apply here as we can only reach this point
  82          * once with any loop.
  83          * When this function completes, either bp[page].map or
  84          * bp[page].hijacked.  In either case, this function will
  85          * abort before getting to this point again.  So there is
  86          * no risk of a free-spin, and so it is safe to assert
  87          * that sleeping here is allowed.
  88          */
  89         sched_annotate_sleep();
  90         mappage = kzalloc(PAGE_SIZE, GFP_NOIO);
  91         spin_lock_irq(&bitmap->lock);
  92
  93         if (mappage == NULL) {
  94                 pr_debug("md/bitmap: map page allocation failed, hijacking\n");
  95                 /* We don't support hijack for cluster raid */
  96                 if (no_hijack)
  97                         return -ENOMEM;
  98                 /* failed - set the hijacked flag so that we can use the
  99                  * pointer as a counter */
 100                 if (!bitmap->bp[page].map)
 101                         bitmap->bp[page].hijacked = 1;
 102         } else if (bitmap->bp[page].map ||
 103                    bitmap->bp[page].hijacked) {
 104                 /* somebody beat us to getting the page */
 105                 kfree(mappage);
 106         } else {
 107
 108                 /* no page was in place and we have one, so install it */
 109
 110                 bitmap->bp[page].map = mappage;
 111                 bitmap->missing_pages--;
 112         }
 113         return 0;
 114 }
 115
 116 /* if page is completely empty, put it back on the free list, or dealloc it */
 117 /* if page was hijacked, unmark the flag so it might get alloced next time */
 118 /* Note: lock should be held when calling this */
 119 static void md_bitmap_checkfree(struct bitmap_counts *bitmap, unsigned long page)
 120 {
 121         char *ptr;
 122
 123         if (bitmap->bp[page].count) /* page is still busy */
 124                 return;
 125
 126         /* page is no longer in use, it can be released */
 127
 128         if (bitmap->bp[page].hijacked) { /* page was hijacked, undo this now */
 129                 bitmap->bp[page].hijacked = 0;
 130                 bitmap->bp[page].map = NULL;
 131         } else {
 132                 /* normal case, free the page */
 133                 ptr = bitmap->bp[page].map;
 134                 bitmap->bp[page].map = NULL;
 135                 bitmap->missing_pages++;
 136                 kfree(ptr);
 137         }
 138 }
 139
 140 /*
 141  * bitmap file handling - read and write the bitmap file and its superblock
 142  */
 143
 144 /*
 145  * basic page I/O operations
 146  */
 147
 148 /* IO operations when bitmap is stored near all superblocks */
 149 static int read_sb_page(struct mddev *mddev, loff_t offset,
 150                         struct page *page,
 151                         unsigned long index, int size)
 152 {
 153         /* choose a good rdev and read the page from there */
 154
 155         struct md_rdev *rdev;
 156         sector_t target;
 157
 158         rdev_for_each(rdev, mddev) {
 159                 if (! test_bit(In_sync, &rdev->flags)
 160                     || test_bit(Faulty, &rdev->flags)
 161                     || test_bit(Bitmap_sync, &rdev->flags))
 162                         continue;
 163
 164                 target = offset + index * (PAGE_SIZE/512);
 165
 166                 if (sync_page_io(rdev, target,
 167                                  roundup(size, bdev_logical_block_size(rdev->bdev)),
 168                                  page, REQ_OP_READ, 0, true)) {
 169                         page->index = index;
 170                         return 0;
 171                 }
 172         }
 173         return -EIO;
 174 }
 175
 176 static struct md_rdev *next_active_rdev(struct md_rdev *rdev, struct mddev *mddev)
 177 {
 178         /* Iterate the disks of an mddev, using rcu to protect access to the
 179          * linked list, and raising the refcount of devices we return to ensure
 180          * they don't disappear while in use.
 181          * As devices are only added or removed when raid_disk is < 0 and
 182          * nr_pending is 0 and In_sync is clear, the entries we return will
 183          * still be in the same position on the list when we re-enter
 184          * list_for_each_entry_continue_rcu.
 185          *
 186          * Note that if entered with 'rdev == NULL' to start at the
 187          * beginning, we temporarily assign 'rdev' to an address which
 188          * isn't really an rdev, but which can be used by
 189          * list_for_each_entry_continue_rcu() to find the first entry.
 190          */
 191         rcu_read_lock();
 192         if (rdev == NULL)
 193                 /* start at the beginning */
 194                 rdev = list_entry(&mddev->disks, struct md_rdev, same_set);
 195         else {
 196                 /* release the previous rdev and start from there. */
 197                 rdev_dec_pending(rdev, mddev);
 198         }
 199         list_for_each_entry_continue_rcu(rdev, &mddev->disks, same_set) {
 200                 if (rdev->raid_disk >= 0 &&
 201                     !test_bit(Faulty, &rdev->flags)) {
 202                         /* this is a usable devices */
 203                         atomic_inc(&rdev->nr_pending);
 204                         rcu_read_unlock();
 205                         return rdev;
 206                 }
 207         }
 208         rcu_read_unlock();
 209         return NULL;
 210 }
 211
 212 static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
 213 {
 214         struct md_rdev *rdev;
 215         struct block_device *bdev;
 216         struct mddev *mddev = bitmap->mddev;
 217         struct bitmap_storage *store = &bitmap->storage;
 218
 219 restart:
 220         rdev = NULL;
 221         while ((rdev = next_active_rdev(rdev, mddev)) != NULL) {
 222                 int size = PAGE_SIZE;
 223                 loff_t offset = mddev->bitmap_info.offset;
 224
 225                 bdev = (rdev->meta_bdev) ? rdev->meta_bdev : rdev->bdev;
 226
 227                 if (page->index == store->file_pages-1) {
 228                         int last_page_size = store->bytes & (PAGE_SIZE-1);
 229                         if (last_page_size == 0)
 230                                 last_page_size = PAGE_SIZE;
 231                         size = roundup(last_page_size,
 232                                        bdev_logical_block_size(bdev));
 233                 }
 234                 /* Just make sure we aren't corrupting data or
 235                  * metadata
 236                  */
 237                 if (mddev->external) {
 238                         /* Bitmap could be anywhere. */
 239                         if (rdev->sb_start + offset + (page->index
 240                                                        * (PAGE_SIZE/512))
 241                             > rdev->data_offset
 242                             &&
 243                             rdev->sb_start + offset
 244                             < (rdev->data_offset + mddev->dev_sectors
 245                              + (PAGE_SIZE/512)))
 246                                 goto bad_alignment;
 247                 } else if (offset < 0) {
 248                         /* DATA  BITMAP METADATA  */
 249                         if (offset
 250                             + (long)(page->index * (PAGE_SIZE/512))
 251                             + size/512 > 0)
 252                                 /* bitmap runs in to metadata */
 253                                 goto bad_alignment;
 254                         if (rdev->data_offset + mddev->dev_sectors
 255                             > rdev->sb_start + offset)
 256                                 /* data runs in to bitmap */
 257                                 goto bad_alignment;
 258                 } else if (rdev->sb_start < rdev->data_offset) {
 259                         /* METADATA BITMAP DATA */
 260                         if (rdev->sb_start
 261                             + offset
 262                             + page->index*(PAGE_SIZE/512) + size/512
 263                             > rdev->data_offset)
 264                                 /* bitmap runs in to data */
 265                                 goto bad_alignment;
 266                 } else {
 267                         /* DATA METADATA BITMAP - no problems */
 268                 }
 269                 md_super_write(mddev, rdev,
 270                                rdev->sb_start + offset
 271                                + page->index * (PAGE_SIZE/512),
 272                                size,
 273                                page);
 274         }
 275
 276         if (wait && md_super_wait(mddev) < 0)
 277                 goto restart;
 278         return 0;
 279
 280  bad_alignment:
 281         return -EINVAL;
 282 }
 283
 284 static void md_bitmap_file_kick(struct bitmap *bitmap);
 285 /*
 286  * write out a page to a file
 287  */
 288 static void write_page(struct bitmap *bitmap, struct page *page, int wait)
 289 {
 290         struct buffer_head *bh;
 291
 292         if (bitmap->storage.file == NULL) {
 293                 switch (write_sb_page(bitmap, page, wait)) {
 294                 case -EINVAL:
 295                         set_bit(BITMAP_WRITE_ERROR, &bitmap->flags);
 296                 }
 297         } else {
 298
 299                 bh = page_buffers(page);
 300
 301                 while (bh && bh->b_blocknr) {
 302                         atomic_inc(&bitmap->pending_writes);
 303                         set_buffer_locked(bh);
 304                         set_buffer_mapped(bh);
 305                         submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
 306                         bh = bh->b_this_page;
 307                 }
 308
 309                 if (wait)
 310                         wait_event(bitmap->write_wait,
 311                                    atomic_read(&bitmap->pending_writes)==0);
 312         }
 313         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
 314                 md_bitmap_file_kick(bitmap);
 315 }
 316
 317 static void end_bitmap_write(struct buffer_head *bh, int uptodate)
 318 {
 319         struct bitmap *bitmap = bh->b_private;
 320
 321         if (!uptodate)
 322                 set_bit(BITMAP_WRITE_ERROR, &bitmap->flags);
 323         if (atomic_dec_and_test(&bitmap->pending_writes))
 324                 wake_up(&bitmap->write_wait);
 325 }
 326
 327 static void free_buffers(struct page *page)
 328 {
 329         struct buffer_head *bh;
 330
 331         if (!PagePrivate(page))
 332                 return;
 333
 334         bh = page_buffers(page);
 335         while (bh) {
 336                 struct buffer_head *next = bh->b_this_page;
 337                 free_buffer_head(bh);
 338                 bh = next;
 339         }
 340         detach_page_private(page);
 341         put_page(page);
 342 }
 343
 344 /* read a page from a file.
 345  * We both read the page, and attach buffers to the page to record the
 346  * address of each block (using bmap).  These addresses will be used
 347  * to write the block later, completely bypassing the filesystem.
 348  * This usage is similar to how swap files are handled, and allows us
 349  * to write to a file with no concerns of memory allocation failing.
 350  */
 351 static int read_page(struct file *file, unsigned long index,
 352                      struct bitmap *bitmap,
 353                      unsigned long count,
 354                      struct page *page)
 355 {
 356         int ret = 0;
 357         struct inode *inode = file_inode(file);
 358         struct buffer_head *bh;
 359         sector_t block, blk_cur;
 360
 361         pr_debug("read bitmap file (%dB @ %llu)\n", (int)PAGE_SIZE,
 362                  (unsigned long long)index << PAGE_SHIFT);
 363
 364         bh = alloc_page_buffers(page, 1<<inode->i_blkbits, false);
 365         if (!bh) {
 366                 ret = -ENOMEM;
 367                 goto out;
 368         }
 369         attach_page_private(page, bh);
 370         blk_cur = index << (PAGE_SHIFT - inode->i_blkbits);
 371         while (bh) {
 372                 block = blk_cur;
 373
 374                 if (count == 0)
 375                         bh->b_blocknr = 0;
 376                 else {
 377                         ret = bmap(inode, &block);
 378                         if (ret || !block) {
 379                                 ret = -EINVAL;
 380                                 bh->b_blocknr = 0;
 381                                 goto out;
 382                         }
 383
 384                         bh->b_blocknr = block;
 385                         bh->b_bdev = inode->i_sb->s_bdev;
 386                         if (count < (1<<inode->i_blkbits))
 387                                 count = 0;
 388                         else
 389                                 count -= (1<<inode->i_blkbits);
 390
 391                         bh->b_end_io = end_bitmap_write;
 392                         bh->b_private = bitmap;
 393                         atomic_inc(&bitmap->pending_writes);
 394                         set_buffer_locked(bh);
 395                         set_buffer_mapped(bh);
 396                         submit_bh(REQ_OP_READ, 0, bh);
 397                 }
 398                 blk_cur++;
 399                 bh = bh->b_this_page;
 400         }
 401         page->index = index;
 402
 403         wait_event(bitmap->write_wait,
 404                    atomic_read(&bitmap->pending_writes)==0);
 405         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
 406                 ret = -EIO;
 407 out:
 408         if (ret)
 409                 pr_err("md: bitmap read error: (%dB @ %llu): %d\n",
 410                        (int)PAGE_SIZE,
 411                        (unsigned long long)index << PAGE_SHIFT,
 412                        ret);
 413         return ret;
 414 }
 415
 416 /*
 417  * bitmap file superblock operations
 418  */
 419
 420 /*
 421  * md_bitmap_wait_writes() should be called before writing any bitmap
 422  * blocks, to ensure previous writes, particularly from
 423  * md_bitmap_daemon_work(), have completed.
 424  */
 425 static void md_bitmap_wait_writes(struct bitmap *bitmap)
 426 {
 427         if (bitmap->storage.file)
 428                 wait_event(bitmap->write_wait,
 429                            atomic_read(&bitmap->pending_writes)==0);
 430         else
 431                 /* Note that we ignore the return value.  The writes
 432                  * might have failed, but that would just mean that
 433                  * some bits which should be cleared haven't been,
 434                  * which is safe.  The relevant bitmap blocks will
 435                  * probably get written again, but there is no great
 436                  * loss if they aren't.
 437                  */
 438                 md_super_wait(bitmap->mddev);
 439 }
 440
 441
 442 /* update the event counter and sync the superblock to disk */
 443 void md_bitmap_update_sb(struct bitmap *bitmap)
 444 {
 445         bitmap_super_t *sb;
 446
 447         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
 448                 return;
 449         if (bitmap->mddev->bitmap_info.external)
 450                 return;
 451         if (!bitmap->storage.sb_page) /* no superblock */
 452                 return;
 453         sb = kmap_atomic(bitmap->storage.sb_page);
 454         sb->events = cpu_to_le64(bitmap->mddev->events);
 455         if (bitmap->mddev->events < bitmap->events_cleared)
 456                 /* rocking back to read-only */
 457                 bitmap->events_cleared = bitmap->mddev->events;
 458         sb->events_cleared = cpu_to_le64(bitmap->events_cleared);
 459         /*
 460          * clear BITMAP_WRITE_ERROR bit to protect against the case that
 461          * a bitmap write error occurred but the later writes succeeded.
 462          */
 463         sb->state = cpu_to_le32(bitmap->flags & ~BIT(BITMAP_WRITE_ERROR));
 464         /* Just in case these have been changed via sysfs: */
 465         sb->daemon_sleep = cpu_to_le32(bitmap->mddev->bitmap_info.daemon_sleep/HZ);
 466         sb->write_behind = cpu_to_le32(bitmap->mddev->bitmap_info.max_write_behind);
 467         /* This might have been changed by a reshape */
 468         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 469         sb->chunksize = cpu_to_le32(bitmap->mddev->bitmap_info.chunksize);
 470         sb->nodes = cpu_to_le32(bitmap->mddev->bitmap_info.nodes);
 471         sb->sectors_reserved = cpu_to_le32(bitmap->mddev->
 472                                            bitmap_info.space);
 473         kunmap_atomic(sb);
 474         write_page(bitmap, bitmap->storage.sb_page, 1);
 475 }
 476 EXPORT_SYMBOL(md_bitmap_update_sb);
 477
 478 /* print out the bitmap file superblock */
 479 void md_bitmap_print_sb(struct bitmap *bitmap)
 480 {
 481         bitmap_super_t *sb;
 482
 483         if (!bitmap || !bitmap->storage.sb_page)
 484                 return;
 485         sb = kmap_atomic(bitmap->storage.sb_page);
 486         pr_debug("%s: bitmap file superblock:\n", bmname(bitmap));
 487         pr_debug("         magic: %08x\n", le32_to_cpu(sb->magic));
 488         pr_debug("       version: %d\n", le32_to_cpu(sb->version));
 489         pr_debug("          uuid: %08x.%08x.%08x.%08x\n",
 490                  le32_to_cpu(*(__le32 *)(sb->uuid+0)),
 491                  le32_to_cpu(*(__le32 *)(sb->uuid+4)),
 492                  le32_to_cpu(*(__le32 *)(sb->uuid+8)),
 493                  le32_to_cpu(*(__le32 *)(sb->uuid+12)));
 494         pr_debug("        events: %llu\n",
 495                  (unsigned long long) le64_to_cpu(sb->events));
 496         pr_debug("events cleared: %llu\n",
 497                  (unsigned long long) le64_to_cpu(sb->events_cleared));
 498         pr_debug("         state: %08x\n", le32_to_cpu(sb->state));
 499         pr_debug("     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
 500         pr_debug("  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
 501         pr_debug("     sync size: %llu KB\n",
 502                  (unsigned long long)le64_to_cpu(sb->sync_size)/2);
 503         pr_debug("max write behind: %d\n", le32_to_cpu(sb->write_behind));
 504         kunmap_atomic(sb);
 505 }
 506
 507 /*
 508  * bitmap_new_disk_sb
 509  * @bitmap
 510  *
 511  * This function is somewhat the reverse of bitmap_read_sb.  bitmap_read_sb
 512  * reads and verifies the on-disk bitmap superblock and populates bitmap_info.
 513  * This function verifies 'bitmap_info' and populates the on-disk bitmap
 514  * structure, which is to be written to disk.
 515  *
 516  * Returns: 0 on success, -Exxx on error
 517  */
 518 static int md_bitmap_new_disk_sb(struct bitmap *bitmap)
 519 {
 520         bitmap_super_t *sb;
 521         unsigned long chunksize, daemon_sleep, write_behind;
 522
 523         bitmap->storage.sb_page = alloc_page(GFP_KERNEL | __GFP_ZERO);
 524         if (bitmap->storage.sb_page == NULL)
 525                 return -ENOMEM;
 526         bitmap->storage.sb_page->index = 0;
 527
 528         sb = kmap_atomic(bitmap->storage.sb_page);
 529
 530         sb->magic = cpu_to_le32(BITMAP_MAGIC);
 531         sb->version = cpu_to_le32(BITMAP_MAJOR_HI);
 532
 533         chunksize = bitmap->mddev->bitmap_info.chunksize;
 534         BUG_ON(!chunksize);
 535         if (!is_power_of_2(chunksize)) {
 536                 kunmap_atomic(sb);
 537                 pr_warn("bitmap chunksize not a power of 2\n");
 538                 return -EINVAL;
 539         }
 540         sb->chunksize = cpu_to_le32(chunksize);
 541
 542         daemon_sleep = bitmap->mddev->bitmap_info.daemon_sleep;
 543         if (!daemon_sleep || (daemon_sleep > MAX_SCHEDULE_TIMEOUT)) {
 544                 pr_debug("Choosing daemon_sleep default (5 sec)\n");
 545                 daemon_sleep = 5 * HZ;
 546         }
 547         sb->daemon_sleep = cpu_to_le32(daemon_sleep);
 548         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 549
 550         /*
 551          * FIXME: write_behind for RAID1.  If not specified, what
 552          * is a good choice?  We choose COUNTER_MAX / 2 arbitrarily.
 553          */
 554         write_behind = bitmap->mddev->bitmap_info.max_write_behind;
 555         if (write_behind > COUNTER_MAX)
 556                 write_behind = COUNTER_MAX / 2;
 557         sb->write_behind = cpu_to_le32(write_behind);
 558         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 559
 560         /* keep the array size field of the bitmap superblock up to date */
 561         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 562
 563         memcpy(sb->uuid, bitmap->mddev->uuid, 16);
 564
 565         set_bit(BITMAP_STALE, &bitmap->flags);
 566         sb->state = cpu_to_le32(bitmap->flags);
 567         bitmap->events_cleared = bitmap->mddev->events;
 568         sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
 569         bitmap->mddev->bitmap_info.nodes = 0;
 570
 571         kunmap_atomic(sb);
 572
 573         return 0;
 574 }
 575
 576 /* read the superblock from the bitmap file and initialize some bitmap fields */
 577 static int md_bitmap_read_sb(struct bitmap *bitmap)
 578 {
 579         char *reason = NULL;
 580         bitmap_super_t *sb;
 581         unsigned long chunksize, daemon_sleep, write_behind;
 582         unsigned long long events;
 583         int nodes = 0;
 584         unsigned long sectors_reserved = 0;
 585         int err = -EINVAL;
 586         struct page *sb_page;
 587         loff_t offset = bitmap->mddev->bitmap_info.offset;
 588
 589         if (!bitmap->storage.file && !bitmap->mddev->bitmap_info.offset) {
 590                 chunksize = 128 * 1024 * 1024;
 591                 daemon_sleep = 5 * HZ;
 592                 write_behind = 0;
 593                 set_bit(BITMAP_STALE, &bitmap->flags);
 594                 err = 0;
 595                 goto out_no_sb;
 596         }
 597         /* page 0 is the superblock, read it... */
 598         sb_page = alloc_page(GFP_KERNEL);
 599         if (!sb_page)
 600                 return -ENOMEM;
 601         bitmap->storage.sb_page = sb_page;
 602
 603 re_read:
 604         /* If cluster_slot is set, the cluster is setup */
 605         if (bitmap->cluster_slot >= 0) {
 606                 sector_t bm_blocks = bitmap->mddev->resync_max_sectors;
 607
 608                 sector_div(bm_blocks,
 609                            bitmap->mddev->bitmap_info.chunksize >> 9);
 610                 /* bits to bytes */
 611                 bm_blocks = ((bm_blocks+7) >> 3) + sizeof(bitmap_super_t);
 612                 /* to 4k blocks */
 613                 bm_blocks = DIV_ROUND_UP_SECTOR_T(bm_blocks, 4096);
 614                 offset = bitmap->mddev->bitmap_info.offset + (bitmap->cluster_slot * (bm_blocks << 3));
 615                 pr_debug("%s:%d bm slot: %d offset: %llu\n", __func__, __LINE__,
 616                         bitmap->cluster_slot, offset);
 617         }
 618
 619         if (bitmap->storage.file) {
 620                 loff_t isize = i_size_read(bitmap->storage.file->f_mapping->host);
 621                 int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
 622
 623                 err = read_page(bitmap->storage.file, 0,
 624                                 bitmap, bytes, sb_page);
 625         } else {
 626                 err = read_sb_page(bitmap->mddev,
 627                                    offset,
 628                                    sb_page,
 629                                    0, sizeof(bitmap_super_t));
 630         }
 631         if (err)
 632                 return err;
 633
 634         err = -EINVAL;
 635         sb = kmap_atomic(sb_page);
 636
 637         chunksize = le32_to_cpu(sb->chunksize);
 638         daemon_sleep = le32_to_cpu(sb->daemon_sleep) * HZ;
 639         write_behind = le32_to_cpu(sb->write_behind);
 640         sectors_reserved = le32_to_cpu(sb->sectors_reserved);
 641         /* Setup nodes/clustername only if bitmap version is
 642          * cluster-compatible
 643          */
 644         if (sb->version == cpu_to_le32(BITMAP_MAJOR_CLUSTERED)) {
 645                 nodes = le32_to_cpu(sb->nodes);
 646                 strlcpy(bitmap->mddev->bitmap_info.cluster_name,
 647                                 sb->cluster_name, 64);
 648         }
 649
 650         /* verify that the bitmap-specific fields are valid */
 651         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
 652                 reason = "bad magic";
 653         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
 654                  le32_to_cpu(sb->version) > BITMAP_MAJOR_CLUSTERED)
 655                 reason = "unrecognized superblock version";
 656         else if (chunksize < 512)
 657                 reason = "bitmap chunksize too small";
 658         else if (!is_power_of_2(chunksize))
 659                 reason = "bitmap chunksize not a power of 2";
 660         else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT)
 661                 reason = "daemon sleep period out of range";
 662         else if (write_behind > COUNTER_MAX)
 663                 reason = "write-behind limit out of range (0 - 16383)";
 664         if (reason) {
 665                 pr_warn("%s: invalid bitmap file superblock: %s\n",
 666                         bmname(bitmap), reason);
 667                 goto out;
 668         }
 669
 670         /* keep the array size field of the bitmap superblock up to date */
 671         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 672
 673         if (bitmap->mddev->persistent) {
 674                 /*
 675                  * We have a persistent array superblock, so compare the
 676                  * bitmap's UUID and event counter to the mddev's
 677                  */
 678                 if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
 679                         pr_warn("%s: bitmap superblock UUID mismatch\n",
 680                                 bmname(bitmap));
 681                         goto out;
 682                 }
 683                 events = le64_to_cpu(sb->events);
 684                 if (!nodes && (events < bitmap->mddev->events)) {
 685                         pr_warn("%s: bitmap file is out of date (%llu < %llu) -- forcing full recovery\n",
 686                                 bmname(bitmap), events,
 687                                 (unsigned long long) bitmap->mddev->events);
 688                         set_bit(BITMAP_STALE, &bitmap->flags);
 689                 }
 690         }
 691
 692         /* assign fields using values from superblock */
 693         bitmap->flags |= le32_to_cpu(sb->state);
 694         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
 695                 set_bit(BITMAP_HOSTENDIAN, &bitmap->flags);
 696         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
 697         strlcpy(bitmap->mddev->bitmap_info.cluster_name, sb->cluster_name, 64);
 698         err = 0;
 699
 700 out:
 701         kunmap_atomic(sb);
 702         /* Assigning chunksize is required for "re_read" */
 703         bitmap->mddev->bitmap_info.chunksize = chunksize;
 704         if (err == 0 && nodes && (bitmap->cluster_slot < 0)) {
 705                 err = md_setup_cluster(bitmap->mddev, nodes);
 706                 if (err) {
 707                         pr_warn("%s: Could not setup cluster service (%d)\n",
 708                                 bmname(bitmap), err);
 709                         goto out_no_sb;
 710                 }
 711                 bitmap->cluster_slot = md_cluster_ops->slot_number(bitmap->mddev);
 712                 goto re_read;
 713         }
 714
 715
 716 out_no_sb:
 717         if (test_bit(BITMAP_STALE, &bitmap->flags))
 718                 bitmap->events_cleared = bitmap->mddev->events;
 719         bitmap->mddev->bitmap_info.chunksize = chunksize;
 720         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 721         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 722         bitmap->mddev->bitmap_info.nodes = nodes;
 723         if (bitmap->mddev->bitmap_info.space == 0 ||
 724             bitmap->mddev->bitmap_info.space > sectors_reserved)
 725                 bitmap->mddev->bitmap_info.space = sectors_reserved;
 726         if (err) {
 727                 md_bitmap_print_sb(bitmap);
 728                 if (bitmap->cluster_slot < 0)
 729                         md_cluster_stop(bitmap->mddev);
 730         }
 731         return err;
 732 }
 733
 734 /*
 735  * general bitmap file operations
 736  */
 737
 738 /*
 739  * on-disk bitmap:
 740  *
 741  * Use one bit per "chunk" (block set). We do the disk I/O on the bitmap
 742  * file a page at a time. There's a superblock at the start of the file.
 743  */
 744 /* calculate the index of the page that contains this bit */
 745 static inline unsigned long file_page_index(struct bitmap_storage *store,
 746                                             unsigned long chunk)
 747 {
 748         if (store->sb_page)
 749                 chunk += sizeof(bitmap_super_t) << 3;
 750         return chunk >> PAGE_BIT_SHIFT;
 751 }
 752
 753 /* calculate the (bit) offset of this bit within a page */
 754 static inline unsigned long file_page_offset(struct bitmap_storage *store,
 755                                              unsigned long chunk)
 756 {
 757         if (store->sb_page)
 758                 chunk += sizeof(bitmap_super_t) << 3;
 759         return chunk & (PAGE_BITS - 1);
 760 }
 761
 762 /*
 763  * return a pointer to the page in the filemap that contains the given bit
 764  *
 765  */
 766 static inline struct page *filemap_get_page(struct bitmap_storage *store,
 767                                             unsigned long chunk)
 768 {
 769         if (file_page_index(store, chunk) >= store->file_pages)
 770                 return NULL;
 771         return store->filemap[file_page_index(store, chunk)];
 772 }
 773
 774 static int md_bitmap_storage_alloc(struct bitmap_storage *store,
 775                                    unsigned long chunks, int with_super,
 776                                    int slot_number)
 777 {
 778         int pnum, offset = 0;
 779         unsigned long num_pages;
 780         unsigned long bytes;
 781
 782         bytes = DIV_ROUND_UP(chunks, 8);
 783         if (with_super)
 784                 bytes += sizeof(bitmap_super_t);
 785
 786         num_pages = DIV_ROUND_UP(bytes, PAGE_SIZE);
 787         offset = slot_number * num_pages;
 788
 789         store->filemap = kmalloc_array(num_pages, sizeof(struct page *),
 790                                        GFP_KERNEL);
 791         if (!store->filemap)
 792                 return -ENOMEM;
 793
 794         if (with_super && !store->sb_page) {
 795                 store->sb_page = alloc_page(GFP_KERNEL|__GFP_ZERO);
 796                 if (store->sb_page == NULL)
 797                         return -ENOMEM;
 798         }
 799
 800         pnum = 0;
 801         if (store->sb_page) {
 802                 store->filemap[0] = store->sb_page;
 803                 pnum = 1;
 804                 store->sb_page->index = offset;
 805         }
 806
 807         for ( ; pnum < num_pages; pnum++) {
 808                 store->filemap[pnum] = alloc_page(GFP_KERNEL|__GFP_ZERO);
 809                 if (!store->filemap[pnum]) {
 810                         store->file_pages = pnum;
 811                         return -ENOMEM;
 812                 }
 813                 store->filemap[pnum]->index = pnum + offset;
 814         }
 815         store->file_pages = pnum;
 816
 817         /* We need 4 bits per page, rounded up to a multiple
 818          * of sizeof(unsigned long) */
 819         store->filemap_attr = kzalloc(
 820                 roundup(DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
 821                 GFP_KERNEL);
 822         if (!store->filemap_attr)
 823                 return -ENOMEM;
 824
 825         store->bytes = bytes;
 826
 827         return 0;
 828 }
 829
 830 static void md_bitmap_file_unmap(struct bitmap_storage *store)
 831 {
 832         struct page **map, *sb_page;
 833         int pages;
 834         struct file *file;
 835
 836         file = store->file;
 837         map = store->filemap;
 838         pages = store->file_pages;
 839         sb_page = store->sb_page;
 840
 841         while (pages--)
 842                 if (map[pages] != sb_page) /* 0 is sb_page, release it below */
 843                         free_buffers(map[pages]);
 844         kfree(map);
 845         kfree(store->filemap_attr);
 846
 847         if (sb_page)
 848                 free_buffers(sb_page);
 849
 850         if (file) {
 851                 struct inode *inode = file_inode(file);
 852                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
 853                 fput(file);
 854         }
 855 }
 856
 857 /*
 858  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
 859  * then it is no longer reliable, so we stop using it and we mark the file
 860  * as failed in the superblock
 861  */
 862 static void md_bitmap_file_kick(struct bitmap *bitmap)
 863 {
 864         char *path, *ptr = NULL;
 865
 866         if (!test_and_set_bit(BITMAP_STALE, &bitmap->flags)) {
 867                 md_bitmap_update_sb(bitmap);
 868
 869                 if (bitmap->storage.file) {
 870                         path = kmalloc(PAGE_SIZE, GFP_KERNEL);
 871                         if (path)
 872                                 ptr = file_path(bitmap->storage.file,
 873                                              path, PAGE_SIZE);
 874
 875                         pr_warn("%s: kicking failed bitmap file %s from array!\n",
 876                                 bmname(bitmap), IS_ERR(ptr) ? "" : ptr);
 877
 878                         kfree(path);
 879                 } else
 880                         pr_warn("%s: disabling internal bitmap due to errors\n",
 881                                 bmname(bitmap));
 882         }
 883 }
 884
 885 enum bitmap_page_attr {
 886         BITMAP_PAGE_DIRTY = 0,     /* there are set bits that need to be synced */
 887         BITMAP_PAGE_PENDING = 1,   /* there are bits that are being cleaned.
 888                                     * i.e. counter is 1 or 2. */
 889         BITMAP_PAGE_NEEDWRITE = 2, /* there are cleared bits that need to be synced */
 890 };
 891
 892 static inline void set_page_attr(struct bitmap *bitmap, int pnum,
 893                                  enum bitmap_page_attr attr)
 894 {
 895         set_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 896 }
 897
 898 static inline void clear_page_attr(struct bitmap *bitmap, int pnum,
 899                                    enum bitmap_page_attr attr)
 900 {
 901         clear_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 902 }
 903
 904 static inline int test_page_attr(struct bitmap *bitmap, int pnum,
 905                                  enum bitmap_page_attr attr)
 906 {
 907         return test_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 908 }
 909
 910 static inline int test_and_clear_page_attr(struct bitmap *bitmap, int pnum,
 911                                            enum bitmap_page_attr attr)
 912 {
 913         return test_and_clear_bit((pnum<<2) + attr,
 914                                   bitmap->storage.filemap_attr);
 915 }
 916 /*
 917  * bitmap_file_set_bit -- called before performing a write to the md device
 918  * to set (and eventually sync) a particular bit in the bitmap file
 919  *
 920  * we set the bit immediately, then we record the page number so that
 921  * when an unplug occurs, we can flush the dirty pages out to disk
 922  */
 923 static void md_bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 924 {
 925         unsigned long bit;
 926         struct page *page;
 927         void *kaddr;
 928         unsigned long chunk = block >> bitmap->counts.chunkshift;
 929         struct bitmap_storage *store = &bitmap->storage;
 930         unsigned long node_offset = 0;
 931
 932         if (mddev_is_clustered(bitmap->mddev))
 933                 node_offset = bitmap->cluster_slot * store->file_pages;
 934
 935         page = filemap_get_page(&bitmap->storage, chunk);
 936         if (!page)
 937                 return;
 938         bit = file_page_offset(&bitmap->storage, chunk);
 939
 940         /* set the bit */
 941         kaddr = kmap_atomic(page);
 942         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
 943                 set_bit(bit, kaddr);
 944         else
 945                 set_bit_le(bit, kaddr);
 946         kunmap_atomic(kaddr);
 947         pr_debug("set file bit %lu page %lu\n", bit, page->index);
 948         /* record page number so it gets flushed to disk when unplug occurs */
 949         set_page_attr(bitmap, page->index - node_offset, BITMAP_PAGE_DIRTY);
 950 }
 951
 952 static void md_bitmap_file_clear_bit(struct bitmap *bitmap, sector_t block)
 953 {
 954         unsigned long bit;
 955         struct page *page;
 956         void *paddr;
 957         unsigned long chunk = block >> bitmap->counts.chunkshift;
 958         struct bitmap_storage *store = &bitmap->storage;
 959         unsigned long node_offset = 0;
 960
 961         if (mddev_is_clustered(bitmap->mddev))
 962                 node_offset = bitmap->cluster_slot * store->file_pages;
 963
 964         page = filemap_get_page(&bitmap->storage, chunk);
 965         if (!page)
 966                 return;
 967         bit = file_page_offset(&bitmap->storage, chunk);
 968         paddr = kmap_atomic(page);
 969         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
 970                 clear_bit(bit, paddr);
 971         else
 972                 clear_bit_le(bit, paddr);
 973         kunmap_atomic(paddr);
 974         if (!test_page_attr(bitmap, page->index - node_offset, BITMAP_PAGE_NEEDWRITE)) {
 975                 set_page_attr(bitmap, page->index - node_offset, BITMAP_PAGE_PENDING);
 976                 bitmap->allclean = 0;
 977         }
 978 }
 979
 980 static int md_bitmap_file_test_bit(struct bitmap *bitmap, sector_t block)
 981 {
 982         unsigned long bit;
 983         struct page *page;
 984         void *paddr;
 985         unsigned long chunk = block >> bitmap->counts.chunkshift;
 986         int set = 0;
 987
 988         page = filemap_get_page(&bitmap->storage, chunk);
 989         if (!page)
 990                 return -EINVAL;
 991         bit = file_page_offset(&bitmap->storage, chunk);
 992         paddr = kmap_atomic(page);
 993         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
 994                 set = test_bit(bit, paddr);
 995         else
 996                 set = test_bit_le(bit, paddr);
 997         kunmap_atomic(paddr);
 998         return set;
 999 }
1000
1001
1002 /* this gets called when the md device is ready to unplug its underlying
1003  * (slave) device queues -- before we let any writes go down, we need to
1004  * sync the dirty pages of the bitmap file to disk */
1005 void md_bitmap_unplug(struct bitmap *bitmap)
1006 {
1007         unsigned long i;
1008         int dirty, need_write;
1009         int writing = 0;
1010
1011         if (!bitmap || !bitmap->storage.filemap ||
1012             test_bit(BITMAP_STALE, &bitmap->flags))
1013                 return;
1014
1015         /* look at each page to see if there are any set bits that need to be
1016          * flushed out to disk */
1017         for (i = 0; i < bitmap->storage.file_pages; i++) {
1018                 dirty = test_and_clear_page_attr(bitmap, i, BITMAP_PAGE_DIRTY);
1019                 need_write = test_and_clear_page_attr(bitmap, i,
1020                                                       BITMAP_PAGE_NEEDWRITE);
1021                 if (dirty || need_write) {
1022                         if (!writing) {
1023                                 md_bitmap_wait_writes(bitmap);
1024                                 if (bitmap->mddev->queue)
1025                                         blk_add_trace_msg(bitmap->mddev->queue,
1026                                                           "md bitmap_unplug");
1027                         }
1028                         clear_page_attr(bitmap, i, BITMAP_PAGE_PENDING);
1029                         write_page(bitmap, bitmap->storage.filemap[i], 0);
1030                         writing = 1;
1031                 }
1032         }
1033         if (writing)
1034                 md_bitmap_wait_writes(bitmap);
1035
1036         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
1037                 md_bitmap_file_kick(bitmap);
1038 }
1039 EXPORT_SYMBOL(md_bitmap_unplug);
1040
1041 static void md_bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
1042 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
1043  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
1044  * memory mapping of the bitmap file
1045  * Special cases:
1046  *   if there's no bitmap file, or if the bitmap file had been
1047  *   previously kicked from the array, we mark all the bits as
1048  *   1's in order to cause a full resync.
1049  *
1050  * We ignore all bits for sectors that end earlier than 'start'.
1051  * This is used when reading an out-of-date bitmap...
1052  */
1053 static int md_bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
1054 {
1055         unsigned long i, chunks, index, oldindex, bit, node_offset = 0;
1056         struct page *page = NULL;
1057         unsigned long bit_cnt = 0;
1058         struct file *file;
1059         unsigned long offset;
1060         int outofdate;
1061         int ret = -ENOSPC;
1062         void *paddr;
1063         struct bitmap_storage *store = &bitmap->storage;
1064
1065         chunks = bitmap->counts.chunks;
1066         file = store->file;
1067
1068         if (!file && !bitmap->mddev->bitmap_info.offset) {
1069                 /* No permanent bitmap - fill with '1s'. */
1070                 store->filemap = NULL;
1071                 store->file_pages = 0;
1072                 for (i = 0; i < chunks ; i++) {
1073                         /* if the disk bit is set, set the memory bit */
1074                         int needed = ((sector_t)(i+1) << (bitmap->counts.chunkshift)
1075                                       >= start);
1076                         md_bitmap_set_memory_bits(bitmap,
1077                                                   (sector_t)i << bitmap->counts.chunkshift,
1078                                                   needed);
1079                 }
1080                 return 0;
1081         }
1082
1083         outofdate = test_bit(BITMAP_STALE, &bitmap->flags);
1084         if (outofdate)
1085                 pr_warn("%s: bitmap file is out of date, doing full recovery\n", bmname(bitmap));
1086
1087         if (file && i_size_read(file->f_mapping->host) < store->bytes) {
1088                 pr_warn("%s: bitmap file too short %lu < %lu\n",
1089                         bmname(bitmap),
1090                         (unsigned long) i_size_read(file->f_mapping->host),
1091                         store->bytes);
1092                 goto err;
1093         }
1094
1095         oldindex = ~0L;
1096         offset = 0;
1097         if (!bitmap->mddev->bitmap_info.external)
1098                 offset = sizeof(bitmap_super_t);
1099
1100         if (mddev_is_clustered(bitmap->mddev))
1101                 node_offset = bitmap->cluster_slot * (DIV_ROUND_UP(store->bytes, PAGE_SIZE));
1102
1103         for (i = 0; i < chunks; i++) {
1104                 int b;
1105                 index = file_page_index(&bitmap->storage, i);
1106                 bit = file_page_offset(&bitmap->storage, i);
1107                 if (index != oldindex) { /* this is a new page, read it in */
1108                         int count;
1109                         /* unmap the old page, we're done with it */
1110                         if (index == store->file_pages-1)
1111                                 count = store->bytes - index * PAGE_SIZE;
1112                         else
1113                                 count = PAGE_SIZE;
1114                         page = store->filemap[index];
1115                         if (file)
1116                                 ret = read_page(file, index, bitmap,
1117                                                 count, page);
1118                         else
1119                                 ret = read_sb_page(
1120                                         bitmap->mddev,
1121                                         bitmap->mddev->bitmap_info.offset,
1122                                         page,
1123                                         index + node_offset, count);
1124
1125                         if (ret)
1126                                 goto err;
1127
1128                         oldindex = index;
1129
1130                         if (outofdate) {
1131                                 /*
1132                                  * if bitmap is out of date, dirty the
1133                                  * whole page and write it out
1134                                  */
1135                                 paddr = kmap_atomic(page);
1136                                 memset(paddr + offset, 0xff,
1137                                        PAGE_SIZE - offset);
1138                                 kunmap_atomic(paddr);
1139                                 write_page(bitmap, page, 1);
1140
1141                                 ret = -EIO;
1142                                 if (test_bit(BITMAP_WRITE_ERROR,
1143                                              &bitmap->flags))
1144                                         goto err;
1145                         }
1146                 }
1147                 paddr = kmap_atomic(page);
1148                 if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
1149                         b = test_bit(bit, paddr);
1150                 else
1151                         b = test_bit_le(bit, paddr);
1152                 kunmap_atomic(paddr);
1153                 if (b) {
1154                         /* if the disk bit is set, set the memory bit */
1155                         int needed = ((sector_t)(i+1) << bitmap->counts.chunkshift
1156                                       >= start);
1157                         md_bitmap_set_memory_bits(bitmap,
1158                                                   (sector_t)i << bitmap->counts.chunkshift,
1159                                                   needed);
1160                         bit_cnt++;
1161                 }
1162                 offset = 0;
1163         }
1164
1165         pr_debug("%s: bitmap initialized from disk: read %lu pages, set %lu of %lu bits\n",
1166                  bmname(bitmap), store->file_pages,
1167                  bit_cnt, chunks);
1168
1169         return 0;
1170
1171  err:
1172         pr_warn("%s: bitmap initialisation failed: %d\n",
1173                 bmname(bitmap), ret);
1174         return ret;
1175 }
1176
1177 void md_bitmap_write_all(struct bitmap *bitmap)
1178 {
1179         /* We don't actually write all bitmap blocks here,
1180          * just flag them as needing to be written
1181          */
1182         int i;
1183
1184         if (!bitmap || !bitmap->storage.filemap)
1185                 return;
1186         if (bitmap->storage.file)
1187                 /* Only one copy, so nothing needed */
1188                 return;
1189
1190         for (i = 0; i < bitmap->storage.file_pages; i++)
1191                 set_page_attr(bitmap, i,
1192                               BITMAP_PAGE_NEEDWRITE);
1193         bitmap->allclean = 0;
1194 }
1195
1196 static void md_bitmap_count_page(struct bitmap_counts *bitmap,
1197                                  sector_t offset, int inc)
1198 {
1199         sector_t chunk = offset >> bitmap->chunkshift;
1200         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1201         bitmap->bp[page].count += inc;
1202         md_bitmap_checkfree(bitmap, page);
1203 }
1204
1205 static void md_bitmap_set_pending(struct bitmap_counts *bitmap, sector_t offset)
1206 {
1207         sector_t chunk = offset >> bitmap->chunkshift;
1208         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1209         struct bitmap_page *bp = &bitmap->bp[page];
1210
1211         if (!bp->pending)
1212                 bp->pending = 1;
1213 }
1214
1215 static bitmap_counter_t *md_bitmap_get_counter(struct bitmap_counts *bitmap,
1216                                                sector_t offset, sector_t *blocks,
1217                                                int create);
1218
1219 /*
1220  * bitmap daemon -- periodically wakes up to clean bits and flush pages
1221  *                      out to disk
1222  */
1223
1224 void md_bitmap_daemon_work(struct mddev *mddev)
1225 {
1226         struct bitmap *bitmap;
1227         unsigned long j;
1228         unsigned long nextpage;
1229         sector_t blocks;
1230         struct bitmap_counts *counts;
1231
1232         /* Use a mutex to guard daemon_work against
1233          * bitmap_destroy.
1234          */
1235         mutex_lock(&mddev->bitmap_info.mutex);
1236         bitmap = mddev->bitmap;
1237         if (bitmap == NULL) {
1238                 mutex_unlock(&mddev->bitmap_info.mutex);
1239                 return;
1240         }
1241         if (time_before(jiffies, bitmap->daemon_lastrun
1242                         + mddev->bitmap_info.daemon_sleep))
1243                 goto done;
1244
1245         bitmap->daemon_lastrun = jiffies;
1246         if (bitmap->allclean) {
1247                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1248                 goto done;
1249         }
1250         bitmap->allclean = 1;
1251
1252         if (bitmap->mddev->queue)
1253                 blk_add_trace_msg(bitmap->mddev->queue,
1254                                   "md bitmap_daemon_work");
1255
1256         /* Any file-page which is PENDING now needs to be written.
1257          * So set NEEDWRITE now, then after we make any last-minute changes
1258          * we will write it.
1259          */
1260         for (j = 0; j < bitmap->storage.file_pages; j++)
1261                 if (test_and_clear_page_attr(bitmap, j,
1262                                              BITMAP_PAGE_PENDING))
1263                         set_page_attr(bitmap, j,
1264                                       BITMAP_PAGE_NEEDWRITE);
1265
1266         if (bitmap->need_sync &&
1267             mddev->bitmap_info.external == 0) {
1268                 /* Arrange for superblock update as well as
1269                  * other changes */
1270                 bitmap_super_t *sb;
1271                 bitmap->need_sync = 0;
1272                 if (bitmap->storage.filemap) {
1273                         sb = kmap_atomic(bitmap->storage.sb_page);
1274                         sb->events_cleared =
1275                                 cpu_to_le64(bitmap->events_cleared);
1276                         kunmap_atomic(sb);
1277                         set_page_attr(bitmap, 0,
1278                                       BITMAP_PAGE_NEEDWRITE);
1279                 }
1280         }
1281         /* Now look at the bitmap counters and if any are '2' or '1',
1282          * decrement and handle accordingly.
1283          */
1284         counts = &bitmap->counts;
1285         spin_lock_irq(&counts->lock);
1286         nextpage = 0;
1287         for (j = 0; j < counts->chunks; j++) {
1288                 bitmap_counter_t *bmc;
1289                 sector_t  block = (sector_t)j << counts->chunkshift;
1290
1291                 if (j == nextpage) {
1292                         nextpage += PAGE_COUNTER_RATIO;
1293                         if (!counts->bp[j >> PAGE_COUNTER_SHIFT].pending) {
1294                                 j |= PAGE_COUNTER_MASK;
1295                                 continue;
1296                         }
1297                         counts->bp[j >> PAGE_COUNTER_SHIFT].pending = 0;
1298                 }
1299
1300                 bmc = md_bitmap_get_counter(counts, block, &blocks, 0);
1301                 if (!bmc) {
1302                         j |= PAGE_COUNTER_MASK;
1303                         continue;
1304                 }
1305                 if (*bmc == 1 && !bitmap->need_sync) {
1306                         /* We can clear the bit */
1307                         *bmc = 0;
1308                         md_bitmap_count_page(counts, block, -1);
1309                         md_bitmap_file_clear_bit(bitmap, block);
1310                 } else if (*bmc && *bmc <= 2) {
1311                         *bmc = 1;
1312                         md_bitmap_set_pending(counts, block);
1313                         bitmap->allclean = 0;
1314                 }
1315         }
1316         spin_unlock_irq(&counts->lock);
1317
1318         md_bitmap_wait_writes(bitmap);
1319         /* Now start writeout on any page in NEEDWRITE that isn't DIRTY.
1320          * DIRTY pages need to be written by bitmap_unplug so it can wait
1321          * for them.
1322          * If we find any DIRTY page we stop there and let bitmap_unplug
1323          * handle all the rest.  This is important in the case where
1324          * the first blocking holds the superblock and it has been updated.
1325          * We mustn't write any other blocks before the superblock.
1326          */
1327         for (j = 0;
1328              j < bitmap->storage.file_pages
1329                      && !test_bit(BITMAP_STALE, &bitmap->flags);
1330              j++) {
1331                 if (test_page_attr(bitmap, j,
1332                                    BITMAP_PAGE_DIRTY))
1333                         /* bitmap_unplug will handle the rest */
1334                         break;
1335                 if (bitmap->storage.filemap &&
1336                     test_and_clear_page_attr(bitmap, j,
1337                                              BITMAP_PAGE_NEEDWRITE)) {
1338                         write_page(bitmap, bitmap->storage.filemap[j], 0);
1339                 }
1340         }
1341
1342  done:
1343         if (bitmap->allclean == 0)
1344                 mddev->thread->timeout =
1345                         mddev->bitmap_info.daemon_sleep;
1346         mutex_unlock(&mddev->bitmap_info.mutex);
1347 }
1348
1349 static bitmap_counter_t *md_bitmap_get_counter(struct bitmap_counts *bitmap,
1350                                                sector_t offset, sector_t *blocks,
1351                                                int create)
1352 __releases(bitmap->lock)
1353 __acquires(bitmap->lock)
1354 {
1355         /* If 'create', we might release the lock and reclaim it.
1356          * The lock must have been taken with interrupts enabled.
1357          * If !create, we don't release the lock.
1358          */
1359         sector_t chunk = offset >> bitmap->chunkshift;
1360         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1361         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1362         sector_t csize;
1363         int err;
1364
1365         err = md_bitmap_checkpage(bitmap, page, create, 0);
1366
1367         if (bitmap->bp[page].hijacked ||
1368             bitmap->bp[page].map == NULL)
1369                 csize = ((sector_t)1) << (bitmap->chunkshift +
1370                                           PAGE_COUNTER_SHIFT - 1);
1371         else
1372                 csize = ((sector_t)1) << bitmap->chunkshift;
1373         *blocks = csize - (offset & (csize - 1));
1374
1375         if (err < 0)
1376                 return NULL;
1377
1378         /* now locked ... */
1379
1380         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1381                 /* should we use the first or second counter field
1382                  * of the hijacked pointer? */
1383                 int hi = (pageoff > PAGE_COUNTER_MASK);
1384                 return  &((bitmap_counter_t *)
1385                           &bitmap->bp[page].map)[hi];
1386         } else /* page is allocated */
1387                 return (bitmap_counter_t *)
1388                         &(bitmap->bp[page].map[pageoff]);
1389 }
1390
1391 int md_bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1392 {
1393         if (!bitmap)
1394                 return 0;
1395
1396         if (behind) {
1397                 int bw;
1398                 atomic_inc(&bitmap->behind_writes);
1399                 bw = atomic_read(&bitmap->behind_writes);
1400                 if (bw > bitmap->behind_writes_used)
1401                         bitmap->behind_writes_used = bw;
1402
1403                 pr_debug("inc write-behind count %d/%lu\n",
1404                          bw, bitmap->mddev->bitmap_info.max_write_behind);
1405         }
1406
1407         while (sectors) {
1408                 sector_t blocks;
1409                 bitmap_counter_t *bmc;
1410
1411                 spin_lock_irq(&bitmap->counts.lock);
1412                 bmc = md_bitmap_get_counter(&bitmap->counts, offset, &blocks, 1);
1413                 if (!bmc) {
1414                         spin_unlock_irq(&bitmap->counts.lock);
1415                         return 0;
1416                 }
1417
1418                 if (unlikely(COUNTER(*bmc) == COUNTER_MAX)) {
1419                         DEFINE_WAIT(__wait);
1420                         /* note that it is safe to do the prepare_to_wait
1421                          * after the test as long as we do it before dropping
1422                          * the spinlock.
1423                          */
1424                         prepare_to_wait(&bitmap->overflow_wait, &__wait,
1425                                         TASK_UNINTERRUPTIBLE);
1426                         spin_unlock_irq(&bitmap->counts.lock);
1427                         schedule();
1428                         finish_wait(&bitmap->overflow_wait, &__wait);
1429                         continue;
1430                 }
1431
1432                 switch (*bmc) {
1433                 case 0:
1434                         md_bitmap_file_set_bit(bitmap, offset);
1435                         md_bitmap_count_page(&bitmap->counts, offset, 1);
1436                         /* fall through */
1437                 case 1:
1438                         *bmc = 2;
1439                 }
1440
1441                 (*bmc)++;
1442
1443                 spin_unlock_irq(&bitmap->counts.lock);
1444
1445                 offset += blocks;
1446                 if (sectors > blocks)
1447                         sectors -= blocks;
1448                 else
1449                         sectors = 0;
1450         }
1451         return 0;
1452 }
1453 EXPORT_SYMBOL(md_bitmap_startwrite);
1454
1455 void md_bitmap_endwrite(struct bitmap *bitmap, sector_t offset,
1456                         unsigned long sectors, int success, int behind)
1457 {
1458         if (!bitmap)
1459                 return;
1460         if (behind) {
1461                 if (atomic_dec_and_test(&bitmap->behind_writes))
1462                         wake_up(&bitmap->behind_wait);
1463                 pr_debug("dec write-behind count %d/%lu\n",
1464                          atomic_read(&bitmap->behind_writes),
1465                          bitmap->mddev->bitmap_info.max_write_behind);
1466         }
1467
1468         while (sectors) {
1469                 sector_t blocks;
1470                 unsigned long flags;
1471                 bitmap_counter_t *bmc;
1472
1473                 spin_lock_irqsave(&bitmap->counts.lock, flags);
1474                 bmc = md_bitmap_get_counter(&bitmap->counts, offset, &blocks, 0);
1475                 if (!bmc) {
1476                         spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1477                         return;
1478                 }
1479
1480                 if (success && !bitmap->mddev->degraded &&
1481                     bitmap->events_cleared < bitmap->mddev->events) {
1482                         bitmap->events_cleared = bitmap->mddev->events;
1483                         bitmap->need_sync = 1;
1484                         sysfs_notify_dirent_safe(bitmap->sysfs_can_clear);
1485                 }
1486
1487                 if (!success && !NEEDED(*bmc))
1488                         *bmc |= NEEDED_MASK;
1489
1490                 if (COUNTER(*bmc) == COUNTER_MAX)
1491                         wake_up(&bitmap->overflow_wait);
1492
1493                 (*bmc)--;
1494                 if (*bmc <= 2) {
1495                         md_bitmap_set_pending(&bitmap->counts, offset);
1496                         bitmap->allclean = 0;
1497                 }
1498                 spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1499                 offset += blocks;
1500                 if (sectors > blocks)
1501                         sectors -= blocks;
1502                 else
1503                         sectors = 0;
1504         }
1505 }
1506 EXPORT_SYMBOL(md_bitmap_endwrite);
1507
1508 static int __bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1509                                int degraded)
1510 {
1511         bitmap_counter_t *bmc;
1512         int rv;
1513         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1514                 *blocks = 1024;
1515                 return 1; /* always resync if no bitmap */
1516         }
1517         spin_lock_irq(&bitmap->counts.lock);
1518         bmc = md_bitmap_get_counter(&bitmap->counts, offset, blocks, 0);
1519         rv = 0;
1520         if (bmc) {
1521                 /* locked */
1522                 if (RESYNC(*bmc))
1523                         rv = 1;
1524                 else if (NEEDED(*bmc)) {
1525                         rv = 1;
1526                         if (!degraded) { /* don't set/clear bits if degraded */
1527                                 *bmc |= RESYNC_MASK;
1528                                 *bmc &= ~NEEDED_MASK;
1529                         }
1530                 }
1531         }
1532         spin_unlock_irq(&bitmap->counts.lock);
1533         return rv;
1534 }
1535
1536 int md_bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1537                          int degraded)
1538 {
1539         /* bitmap_start_sync must always report on multiples of whole
1540          * pages, otherwise resync (which is very PAGE_SIZE based) will
1541          * get confused.
1542          * So call __bitmap_start_sync repeatedly (if needed) until
1543          * At least PAGE_SIZE>>9 blocks are covered.
1544          * Return the 'or' of the result.
1545          */
1546         int rv = 0;
1547         sector_t blocks1;
1548
1549         *blocks = 0;
1550         while (*blocks < (PAGE_SIZE>>9)) {
1551                 rv |= __bitmap_start_sync(bitmap, offset,
1552                                           &blocks1, degraded);
1553                 offset += blocks1;
1554                 *blocks += blocks1;
1555         }
1556         return rv;
1557 }
1558 EXPORT_SYMBOL(md_bitmap_start_sync);
1559
1560 void md_bitmap_end_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks, int aborted)
1561 {
1562         bitmap_counter_t *bmc;
1563         unsigned long flags;
1564
1565         if (bitmap == NULL) {
1566                 *blocks = 1024;
1567                 return;
1568         }
1569         spin_lock_irqsave(&bitmap->counts.lock, flags);
1570         bmc = md_bitmap_get_counter(&bitmap->counts, offset, blocks, 0);
1571         if (bmc == NULL)
1572                 goto unlock;
1573         /* locked */
1574         if (RESYNC(*bmc)) {
1575                 *bmc &= ~RESYNC_MASK;
1576
1577                 if (!NEEDED(*bmc) && aborted)
1578                         *bmc |= NEEDED_MASK;
1579                 else {
1580                         if (*bmc <= 2) {
1581                                 md_bitmap_set_pending(&bitmap->counts, offset);
1582                                 bitmap->allclean = 0;
1583                         }
1584                 }
1585         }
1586  unlock:
1587         spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1588 }
1589 EXPORT_SYMBOL(md_bitmap_end_sync);
1590
1591 void md_bitmap_close_sync(struct bitmap *bitmap)
1592 {
1593         /* Sync has finished, and any bitmap chunks that weren't synced
1594          * properly have been aborted.  It remains to us to clear the
1595          * RESYNC bit wherever it is still on
1596          */
1597         sector_t sector = 0;
1598         sector_t blocks;
1599         if (!bitmap)
1600                 return;
1601         while (sector < bitmap->mddev->resync_max_sectors) {
1602                 md_bitmap_end_sync(bitmap, sector, &blocks, 0);
1603                 sector += blocks;
1604         }
1605 }
1606 EXPORT_SYMBOL(md_bitmap_close_sync);
1607
1608 void md_bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector, bool force)
1609 {
1610         sector_t s = 0;
1611         sector_t blocks;
1612
1613         if (!bitmap)
1614                 return;
1615         if (sector == 0) {
1616                 bitmap->last_end_sync = jiffies;
1617                 return;
1618         }
1619         if (!force && time_before(jiffies, (bitmap->last_end_sync
1620                                   + bitmap->mddev->bitmap_info.daemon_sleep)))
1621                 return;
1622         wait_event(bitmap->mddev->recovery_wait,
1623                    atomic_read(&bitmap->mddev->recovery_active) == 0);
1624
1625         bitmap->mddev->curr_resync_completed = sector;
1626         set_bit(MD_SB_CHANGE_CLEAN, &bitmap->mddev->sb_flags);
1627         sector &= ~((1ULL << bitmap->counts.chunkshift) - 1);
1628         s = 0;
1629         while (s < sector && s < bitmap->mddev->resync_max_sectors) {
1630                 md_bitmap_end_sync(bitmap, s, &blocks, 0);
1631                 s += blocks;
1632         }
1633         bitmap->last_end_sync = jiffies;
1634         sysfs_notify(&bitmap->mddev->kobj, NULL, "sync_completed");
1635 }
1636 EXPORT_SYMBOL(md_bitmap_cond_end_sync);
1637
1638 void md_bitmap_sync_with_cluster(struct mddev *mddev,
1639                               sector_t old_lo, sector_t old_hi,
1640                               sector_t new_lo, sector_t new_hi)
1641 {
1642         struct bitmap *bitmap = mddev->bitmap;
1643         sector_t sector, blocks = 0;
1644
1645         for (sector = old_lo; sector < new_lo; ) {
1646                 md_bitmap_end_sync(bitmap, sector, &blocks, 0);
1647                 sector += blocks;
1648         }
1649         WARN((blocks > new_lo) && old_lo, "alignment is not correct for lo\n");
1650
1651         for (sector = old_hi; sector < new_hi; ) {
1652                 md_bitmap_start_sync(bitmap, sector, &blocks, 0);
1653                 sector += blocks;
1654         }
1655         WARN((blocks > new_hi) && old_hi, "alignment is not correct for hi\n");
1656 }
1657 EXPORT_SYMBOL(md_bitmap_sync_with_cluster);
1658
1659 static void md_bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1660 {
1661         /* For each chunk covered by any of these sectors, set the
1662          * counter to 2 and possibly set resync_needed.  They should all
1663          * be 0 at this point
1664          */
1665
1666         sector_t secs;
1667         bitmap_counter_t *bmc;
1668         spin_lock_irq(&bitmap->counts.lock);
1669         bmc = md_bitmap_get_counter(&bitmap->counts, offset, &secs, 1);
1670         if (!bmc) {
1671                 spin_unlock_irq(&bitmap->counts.lock);
1672                 return;
1673         }
1674         if (!*bmc) {
1675                 *bmc = 2;
1676                 md_bitmap_count_page(&bitmap->counts, offset, 1);
1677                 md_bitmap_set_pending(&bitmap->counts, offset);
1678                 bitmap->allclean = 0;
1679         }
1680         if (needed)
1681                 *bmc |= NEEDED_MASK;
1682         spin_unlock_irq(&bitmap->counts.lock);
1683 }
1684
1685 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
1686 void md_bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1687 {
1688         unsigned long chunk;
1689
1690         for (chunk = s; chunk <= e; chunk++) {
1691                 sector_t sec = (sector_t)chunk << bitmap->counts.chunkshift;
1692                 md_bitmap_set_memory_bits(bitmap, sec, 1);
1693                 md_bitmap_file_set_bit(bitmap, sec);
1694                 if (sec < bitmap->mddev->recovery_cp)
1695                         /* We are asserting that the array is dirty,
1696                          * so move the recovery_cp address back so
1697                          * that it is obvious that it is dirty
1698                          */
1699                         bitmap->mddev->recovery_cp = sec;
1700         }
1701 }
1702
1703 /*
1704  * flush out any pending updates
1705  */
1706 void md_bitmap_flush(struct mddev *mddev)
1707 {
1708         struct bitmap *bitmap = mddev->bitmap;
1709         long sleep;
1710
1711         if (!bitmap) /* there was no bitmap */
1712                 return;
1713
1714         /* run the daemon_work three time to ensure everything is flushed
1715          * that can be
1716          */
1717         sleep = mddev->bitmap_info.daemon_sleep * 2;
1718         bitmap->daemon_lastrun -= sleep;
1719         md_bitmap_daemon_work(mddev);
1720         bitmap->daemon_lastrun -= sleep;
1721         md_bitmap_daemon_work(mddev);
1722         bitmap->daemon_lastrun -= sleep;
1723         md_bitmap_daemon_work(mddev);
1724         md_bitmap_update_sb(bitmap);
1725 }
1726
1727 /*
1728  * free memory that was allocated
1729  */
1730 void md_bitmap_free(struct bitmap *bitmap)
1731 {
1732         unsigned long k, pages;
1733         struct bitmap_page *bp;
1734
1735         if (!bitmap) /* there was no bitmap */
1736                 return;
1737
1738         if (bitmap->sysfs_can_clear)
1739                 sysfs_put(bitmap->sysfs_can_clear);
1740
1741         if (mddev_is_clustered(bitmap->mddev) && bitmap->mddev->cluster_info &&
1742                 bitmap->cluster_slot == md_cluster_ops->slot_number(bitmap->mddev))
1743                 md_cluster_stop(bitmap->mddev);
1744
1745         /* Shouldn't be needed - but just in case.... */
1746         wait_event(bitmap->write_wait,
1747                    atomic_read(&bitmap->pending_writes) == 0);
1748
1749         /* release the bitmap file  */
1750         md_bitmap_file_unmap(&bitmap->storage);
1751
1752         bp = bitmap->counts.bp;
1753         pages = bitmap->counts.pages;
1754
1755         /* free all allocated memory */
1756
1757         if (bp) /* deallocate the page memory */
1758                 for (k = 0; k < pages; k++)
1759                         if (bp[k].map && !bp[k].hijacked)
1760                                 kfree(bp[k].map);
1761         kfree(bp);
1762         kfree(bitmap);
1763 }
1764 EXPORT_SYMBOL(md_bitmap_free);
1765
1766 void md_bitmap_wait_behind_writes(struct mddev *mddev)
1767 {
1768         struct bitmap *bitmap = mddev->bitmap;
1769
1770         /* wait for behind writes to complete */
1771         if (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
1772                 pr_debug("md:%s: behind writes in progress - waiting to stop.\n",
1773                          mdname(mddev));
1774                 /* need to kick something here to make sure I/O goes? */
1775                 wait_event(bitmap->behind_wait,
1776                            atomic_read(&bitmap->behind_writes) == 0);
1777         }
1778 }
1779
1780 void md_bitmap_destroy(struct mddev *mddev)
1781 {
1782         struct bitmap *bitmap = mddev->bitmap;
1783
1784         if (!bitmap) /* there was no bitmap */
1785                 return;
1786
1787         md_bitmap_wait_behind_writes(mddev);
1788         if (!mddev->serialize_policy)
1789                 mddev_destroy_serial_pool(mddev, NULL, true);
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         md_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 *md_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         if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
1820                 pr_notice("md/raid:%s: array with journal cannot have bitmap\n",
1821                           mdname(mddev));
1822                 return ERR_PTR(-EBUSY);
1823         }
1824
1825         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1826         if (!bitmap)
1827                 return ERR_PTR(-ENOMEM);
1828
1829         spin_lock_init(&bitmap->counts.lock);
1830         atomic_set(&bitmap->pending_writes, 0);
1831         init_waitqueue_head(&bitmap->write_wait);
1832         init_waitqueue_head(&bitmap->overflow_wait);
1833         init_waitqueue_head(&bitmap->behind_wait);
1834
1835         bitmap->mddev = mddev;
1836         bitmap->cluster_slot = slot;
1837
1838         if (mddev->kobj.sd)
1839                 bm = sysfs_get_dirent(mddev->kobj.sd, "bitmap");
1840         if (bm) {
1841                 bitmap->sysfs_can_clear = sysfs_get_dirent(bm, "can_clear");
1842                 sysfs_put(bm);
1843         } else
1844                 bitmap->sysfs_can_clear = NULL;
1845
1846         bitmap->storage.file = file;
1847         if (file) {
1848                 get_file(file);
1849                 /* As future accesses to this file will use bmap,
1850                  * and bypass the page cache, we must sync the file
1851                  * first.
1852                  */
1853                 vfs_fsync(file, 1);
1854         }
1855         /* read superblock from bitmap file (this sets mddev->bitmap_info.chunksize) */
1856         if (!mddev->bitmap_info.external) {
1857                 /*
1858                  * If 'MD_ARRAY_FIRST_USE' is set, then device-mapper is
1859                  * instructing us to create a new on-disk bitmap instance.
1860                  */
1861                 if (test_and_clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags))
1862                         err = md_bitmap_new_disk_sb(bitmap);
1863                 else
1864                         err = md_bitmap_read_sb(bitmap);
1865         } else {
1866                 err = 0;
1867                 if (mddev->bitmap_info.chunksize == 0 ||
1868                     mddev->bitmap_info.daemon_sleep == 0)
1869                         /* chunksize and time_base need to be
1870                          * set first. */
1871                         err = -EINVAL;
1872         }
1873         if (err)
1874                 goto error;
1875
1876         bitmap->daemon_lastrun = jiffies;
1877         err = md_bitmap_resize(bitmap, blocks, mddev->bitmap_info.chunksize, 1);
1878         if (err)
1879                 goto error;
1880
1881         pr_debug("created bitmap (%lu pages) for device %s\n",
1882                  bitmap->counts.pages, bmname(bitmap));
1883
1884         err = test_bit(BITMAP_WRITE_ERROR, &bitmap->flags) ? -EIO : 0;
1885         if (err)
1886                 goto error;
1887
1888         return bitmap;
1889  error:
1890         md_bitmap_free(bitmap);
1891         return ERR_PTR(err);
1892 }
1893
1894 int md_bitmap_load(struct mddev *mddev)
1895 {
1896         int err = 0;
1897         sector_t start = 0;
1898         sector_t sector = 0;
1899         struct bitmap *bitmap = mddev->bitmap;
1900         struct md_rdev *rdev;
1901
1902         if (!bitmap)
1903                 goto out;
1904
1905         rdev_for_each(rdev, mddev)
1906                 mddev_create_serial_pool(mddev, rdev, true);
1907
1908         if (mddev_is_clustered(mddev))
1909                 md_cluster_ops->load_bitmaps(mddev, mddev->bitmap_info.nodes);
1910
1911         /* Clear out old bitmap info first:  Either there is none, or we
1912          * are resuming after someone else has possibly changed things,
1913          * so we should forget old cached info.
1914          * All chunks should be clean, but some might need_sync.
1915          */
1916         while (sector < mddev->resync_max_sectors) {
1917                 sector_t blocks;
1918                 md_bitmap_start_sync(bitmap, sector, &blocks, 0);
1919                 sector += blocks;
1920         }
1921         md_bitmap_close_sync(bitmap);
1922
1923         if (mddev->degraded == 0
1924             || bitmap->events_cleared == mddev->events)
1925                 /* no need to keep dirty bits to optimise a
1926                  * re-add of a missing device */
1927                 start = mddev->recovery_cp;
1928
1929         mutex_lock(&mddev->bitmap_info.mutex);
1930         err = md_bitmap_init_from_disk(bitmap, start);
1931         mutex_unlock(&mddev->bitmap_info.mutex);
1932
1933         if (err)
1934                 goto out;
1935         clear_bit(BITMAP_STALE, &bitmap->flags);
1936
1937         /* Kick recovery in case any bits were set */
1938         set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
1939
1940         mddev->thread->timeout = mddev->bitmap_info.daemon_sleep;
1941         md_wakeup_thread(mddev->thread);
1942
1943         md_bitmap_update_sb(bitmap);
1944
1945         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
1946                 err = -EIO;
1947 out:
1948         return err;
1949 }
1950 EXPORT_SYMBOL_GPL(md_bitmap_load);
1951
1952 struct bitmap *get_bitmap_from_slot(struct mddev *mddev, int slot)
1953 {
1954         int rv = 0;
1955         struct bitmap *bitmap;
1956
1957         bitmap = md_bitmap_create(mddev, slot);
1958         if (IS_ERR(bitmap)) {
1959                 rv = PTR_ERR(bitmap);
1960                 return ERR_PTR(rv);
1961         }
1962
1963         rv = md_bitmap_init_from_disk(bitmap, 0);
1964         if (rv) {
1965                 md_bitmap_free(bitmap);
1966                 return ERR_PTR(rv);
1967         }
1968
1969         return bitmap;
1970 }
1971 EXPORT_SYMBOL(get_bitmap_from_slot);
1972
1973 /* Loads the bitmap associated with slot and copies the resync information
1974  * to our bitmap
1975  */
1976 int md_bitmap_copy_from_slot(struct mddev *mddev, int slot,
1977                 sector_t *low, sector_t *high, bool clear_bits)
1978 {
1979         int rv = 0, i, j;
1980         sector_t block, lo = 0, hi = 0;
1981         struct bitmap_counts *counts;
1982         struct bitmap *bitmap;
1983
1984         bitmap = get_bitmap_from_slot(mddev, slot);
1985         if (IS_ERR(bitmap)) {
1986                 pr_err("%s can't get bitmap from slot %d\n", __func__, slot);
1987                 return -1;
1988         }
1989
1990         counts = &bitmap->counts;
1991         for (j = 0; j < counts->chunks; j++) {
1992                 block = (sector_t)j << counts->chunkshift;
1993                 if (md_bitmap_file_test_bit(bitmap, block)) {
1994                         if (!lo)
1995                                 lo = block;
1996                         hi = block;
1997                         md_bitmap_file_clear_bit(bitmap, block);
1998                         md_bitmap_set_memory_bits(mddev->bitmap, block, 1);
1999                         md_bitmap_file_set_bit(mddev->bitmap, block);
2000                 }
2001         }
2002
2003         if (clear_bits) {
2004                 md_bitmap_update_sb(bitmap);
2005                 /* BITMAP_PAGE_PENDING is set, but bitmap_unplug needs
2006                  * BITMAP_PAGE_DIRTY or _NEEDWRITE to write ... */
2007                 for (i = 0; i < bitmap->storage.file_pages; i++)
2008                         if (test_page_attr(bitmap, i, BITMAP_PAGE_PENDING))
2009                                 set_page_attr(bitmap, i, BITMAP_PAGE_NEEDWRITE);
2010                 md_bitmap_unplug(bitmap);
2011         }
2012         md_bitmap_unplug(mddev->bitmap);
2013         *low = lo;
2014         *high = hi;
2015
2016         return rv;
2017 }
2018 EXPORT_SYMBOL_GPL(md_bitmap_copy_from_slot);
2019
2020
2021 void md_bitmap_status(struct seq_file *seq, struct bitmap *bitmap)
2022 {
2023         unsigned long chunk_kb;
2024         struct bitmap_counts *counts;
2025
2026         if (!bitmap)
2027                 return;
2028
2029         counts = &bitmap->counts;
2030
2031         chunk_kb = bitmap->mddev->bitmap_info.chunksize >> 10;
2032         seq_printf(seq, "bitmap: %lu/%lu pages [%luKB], "
2033                    "%lu%s chunk",
2034                    counts->pages - counts->missing_pages,
2035                    counts->pages,
2036                    (counts->pages - counts->missing_pages)
2037                    << (PAGE_SHIFT - 10),
2038                    chunk_kb ? chunk_kb : bitmap->mddev->bitmap_info.chunksize,
2039                    chunk_kb ? "KB" : "B");
2040         if (bitmap->storage.file) {
2041                 seq_printf(seq, ", file: ");
2042                 seq_file_path(seq, bitmap->storage.file, " \t\n");
2043         }
2044
2045         seq_printf(seq, "\n");
2046 }
2047
2048 int md_bitmap_resize(struct bitmap *bitmap, sector_t blocks,
2049                   int chunksize, int init)
2050 {
2051         /* If chunk_size is 0, choose an appropriate chunk size.
2052          * Then possibly allocate new storage space.
2053          * Then quiesce, copy bits, replace bitmap, and re-start
2054          *
2055          * This function is called both to set up the initial bitmap
2056          * and to resize the bitmap while the array is active.
2057          * If this happens as a result of the array being resized,
2058          * chunksize will be zero, and we need to choose a suitable
2059          * chunksize, otherwise we use what we are given.
2060          */
2061         struct bitmap_storage store;
2062         struct bitmap_counts old_counts;
2063         unsigned long chunks;
2064         sector_t block;
2065         sector_t old_blocks, new_blocks;
2066         int chunkshift;
2067         int ret = 0;
2068         long pages;
2069         struct bitmap_page *new_bp;
2070
2071         if (bitmap->storage.file && !init) {
2072                 pr_info("md: cannot resize file-based bitmap\n");
2073                 return -EINVAL;
2074         }
2075
2076         if (chunksize == 0) {
2077                 /* If there is enough space, leave the chunk size unchanged,
2078                  * else increase by factor of two until there is enough space.
2079                  */
2080                 long bytes;
2081                 long space = bitmap->mddev->bitmap_info.space;
2082
2083                 if (space == 0) {
2084                         /* We don't know how much space there is, so limit
2085                          * to current size - in sectors.
2086                          */
2087                         bytes = DIV_ROUND_UP(bitmap->counts.chunks, 8);
2088                         if (!bitmap->mddev->bitmap_info.external)
2089                                 bytes += sizeof(bitmap_super_t);
2090                         space = DIV_ROUND_UP(bytes, 512);
2091                         bitmap->mddev->bitmap_info.space = space;
2092                 }
2093                 chunkshift = bitmap->counts.chunkshift;
2094                 chunkshift--;
2095                 do {
2096                         /* 'chunkshift' is shift from block size to chunk size */
2097                         chunkshift++;
2098                         chunks = DIV_ROUND_UP_SECTOR_T(blocks, 1 << chunkshift);
2099                         bytes = DIV_ROUND_UP(chunks, 8);
2100                         if (!bitmap->mddev->bitmap_info.external)
2101                                 bytes += sizeof(bitmap_super_t);
2102                 } while (bytes > (space << 9));
2103         } else
2104                 chunkshift = ffz(~chunksize) - BITMAP_BLOCK_SHIFT;
2105
2106         chunks = DIV_ROUND_UP_SECTOR_T(blocks, 1 << chunkshift);
2107         memset(&store, 0, sizeof(store));
2108         if (bitmap->mddev->bitmap_info.offset || bitmap->mddev->bitmap_info.file)
2109                 ret = md_bitmap_storage_alloc(&store, chunks,
2110                                               !bitmap->mddev->bitmap_info.external,
2111                                               mddev_is_clustered(bitmap->mddev)
2112                                               ? bitmap->cluster_slot : 0);
2113         if (ret) {
2114                 md_bitmap_file_unmap(&store);
2115                 goto err;
2116         }
2117
2118         pages = DIV_ROUND_UP(chunks, PAGE_COUNTER_RATIO);
2119
2120         new_bp = kcalloc(pages, sizeof(*new_bp), GFP_KERNEL);
2121         ret = -ENOMEM;
2122         if (!new_bp) {
2123                 md_bitmap_file_unmap(&store);
2124                 goto err;
2125         }
2126
2127         if (!init)
2128                 bitmap->mddev->pers->quiesce(bitmap->mddev, 1);
2129
2130         store.file = bitmap->storage.file;
2131         bitmap->storage.file = NULL;
2132
2133         if (store.sb_page && bitmap->storage.sb_page)
2134                 memcpy(page_address(store.sb_page),
2135                        page_address(bitmap->storage.sb_page),
2136                        sizeof(bitmap_super_t));
2137         spin_lock_irq(&bitmap->counts.lock);
2138         md_bitmap_file_unmap(&bitmap->storage);
2139         bitmap->storage = store;
2140
2141         old_counts = bitmap->counts;
2142         bitmap->counts.bp = new_bp;
2143         bitmap->counts.pages = pages;
2144         bitmap->counts.missing_pages = pages;
2145         bitmap->counts.chunkshift = chunkshift;
2146         bitmap->counts.chunks = chunks;
2147         bitmap->mddev->bitmap_info.chunksize = 1 << (chunkshift +
2148                                                      BITMAP_BLOCK_SHIFT);
2149
2150         blocks = min(old_counts.chunks << old_counts.chunkshift,
2151                      chunks << chunkshift);
2152
2153         /* For cluster raid, need to pre-allocate bitmap */
2154         if (mddev_is_clustered(bitmap->mddev)) {
2155                 unsigned long page;
2156                 for (page = 0; page < pages; page++) {
2157                         ret = md_bitmap_checkpage(&bitmap->counts, page, 1, 1);
2158                         if (ret) {
2159                                 unsigned long k;
2160
2161                                 /* deallocate the page memory */
2162                                 for (k = 0; k < page; k++) {
2163                                         kfree(new_bp[k].map);
2164                                 }
2165                                 kfree(new_bp);
2166
2167                                 /* restore some fields from old_counts */
2168                                 bitmap->counts.bp = old_counts.bp;
2169                                 bitmap->counts.pages = old_counts.pages;
2170                                 bitmap->counts.missing_pages = old_counts.pages;
2171                                 bitmap->counts.chunkshift = old_counts.chunkshift;
2172                                 bitmap->counts.chunks = old_counts.chunks;
2173                                 bitmap->mddev->bitmap_info.chunksize = 1 << (old_counts.chunkshift +
2174                                                                              BITMAP_BLOCK_SHIFT);
2175                                 blocks = old_counts.chunks << old_counts.chunkshift;
2176                                 pr_warn("Could not pre-allocate in-memory bitmap for cluster raid\n");
2177                                 break;
2178                         } else
2179                                 bitmap->counts.bp[page].count += 1;
2180                 }
2181         }
2182
2183         for (block = 0; block < blocks; ) {
2184                 bitmap_counter_t *bmc_old, *bmc_new;
2185                 int set;
2186
2187                 bmc_old = md_bitmap_get_counter(&old_counts, block, &old_blocks, 0);
2188                 set = bmc_old && NEEDED(*bmc_old);
2189
2190                 if (set) {
2191                         bmc_new = md_bitmap_get_counter(&bitmap->counts, block, &new_blocks, 1);
2192                         if (*bmc_new == 0) {
2193                                 /* need to set on-disk bits too. */
2194                                 sector_t end = block + new_blocks;
2195                                 sector_t start = block >> chunkshift;
2196                                 start <<= chunkshift;
2197                                 while (start < end) {
2198                                         md_bitmap_file_set_bit(bitmap, block);
2199                                         start += 1 << chunkshift;
2200                                 }
2201                                 *bmc_new = 2;
2202                                 md_bitmap_count_page(&bitmap->counts, block, 1);
2203                                 md_bitmap_set_pending(&bitmap->counts, block);
2204                         }
2205                         *bmc_new |= NEEDED_MASK;
2206                         if (new_blocks < old_blocks)
2207                                 old_blocks = new_blocks;
2208                 }
2209                 block += old_blocks;
2210         }
2211
2212         if (bitmap->counts.bp != old_counts.bp) {
2213                 unsigned long k;
2214                 for (k = 0; k < old_counts.pages; k++)
2215                         if (!old_counts.bp[k].hijacked)
2216                                 kfree(old_counts.bp[k].map);
2217                 kfree(old_counts.bp);
2218         }
2219
2220         if (!init) {
2221                 int i;
2222                 while (block < (chunks << chunkshift)) {
2223                         bitmap_counter_t *bmc;
2224                         bmc = md_bitmap_get_counter(&bitmap->counts, block, &new_blocks, 1);
2225                         if (bmc) {
2226                                 /* new space.  It needs to be resynced, so
2227                                  * we set NEEDED_MASK.
2228                                  */
2229                                 if (*bmc == 0) {
2230                                         *bmc = NEEDED_MASK | 2;
2231                                         md_bitmap_count_page(&bitmap->counts, block, 1);
2232                                         md_bitmap_set_pending(&bitmap->counts, block);
2233                                 }
2234                         }
2235                         block += new_blocks;
2236                 }
2237                 for (i = 0; i < bitmap->storage.file_pages; i++)
2238                         set_page_attr(bitmap, i, BITMAP_PAGE_DIRTY);
2239         }
2240         spin_unlock_irq(&bitmap->counts.lock);
2241
2242         if (!init) {
2243                 md_bitmap_unplug(bitmap);
2244                 bitmap->mddev->pers->quiesce(bitmap->mddev, 0);
2245         }
2246         ret = 0;
2247 err:
2248         return ret;
2249 }
2250 EXPORT_SYMBOL_GPL(md_bitmap_resize);
2251
2252 static ssize_t
2253 location_show(struct mddev *mddev, char *page)
2254 {
2255         ssize_t len;
2256         if (mddev->bitmap_info.file)
2257                 len = sprintf(page, "file");
2258         else if (mddev->bitmap_info.offset)
2259                 len = sprintf(page, "%+lld", (long long)mddev->bitmap_info.offset);
2260         else
2261                 len = sprintf(page, "none");
2262         len += sprintf(page+len, "\n");
2263         return len;
2264 }
2265
2266 static ssize_t
2267 location_store(struct mddev *mddev, const char *buf, size_t len)
2268 {
2269         int rv;
2270
2271         rv = mddev_lock(mddev);
2272         if (rv)
2273                 return rv;
2274         if (mddev->pers) {
2275                 if (!mddev->pers->quiesce) {
2276                         rv = -EBUSY;
2277                         goto out;
2278                 }
2279                 if (mddev->recovery || mddev->sync_thread) {
2280                         rv = -EBUSY;
2281                         goto out;
2282                 }
2283         }
2284
2285         if (mddev->bitmap || mddev->bitmap_info.file ||
2286             mddev->bitmap_info.offset) {
2287                 /* bitmap already configured.  Only option is to clear it */
2288                 if (strncmp(buf, "none", 4) != 0) {
2289                         rv = -EBUSY;
2290                         goto out;
2291                 }
2292                 if (mddev->pers) {
2293                         mddev_suspend(mddev);
2294                         md_bitmap_destroy(mddev);
2295                         mddev_resume(mddev);
2296                 }
2297                 mddev->bitmap_info.offset = 0;
2298                 if (mddev->bitmap_info.file) {
2299                         struct file *f = mddev->bitmap_info.file;
2300                         mddev->bitmap_info.file = NULL;
2301                         fput(f);
2302                 }
2303         } else {
2304                 /* No bitmap, OK to set a location */
2305                 long long offset;
2306                 if (strncmp(buf, "none", 4) == 0)
2307                         /* nothing to be done */;
2308                 else if (strncmp(buf, "file:", 5) == 0) {
2309                         /* Not supported yet */
2310                         rv = -EINVAL;
2311                         goto out;
2312                 } else {
2313                         if (buf[0] == '+')
2314                                 rv = kstrtoll(buf+1, 10, &offset);
2315                         else
2316                                 rv = kstrtoll(buf, 10, &offset);
2317                         if (rv)
2318                                 goto out;
2319                         if (offset == 0) {
2320                                 rv = -EINVAL;
2321                                 goto out;
2322                         }
2323                         if (mddev->bitmap_info.external == 0 &&
2324                             mddev->major_version == 0 &&
2325                             offset != mddev->bitmap_info.default_offset) {
2326                                 rv = -EINVAL;
2327                                 goto out;
2328                         }
2329                         mddev->bitmap_info.offset = offset;
2330                         if (mddev->pers) {
2331                                 struct bitmap *bitmap;
2332                                 bitmap = md_bitmap_create(mddev, -1);
2333                                 mddev_suspend(mddev);
2334                                 if (IS_ERR(bitmap))
2335                                         rv = PTR_ERR(bitmap);
2336                                 else {
2337                                         mddev->bitmap = bitmap;
2338                                         rv = md_bitmap_load(mddev);
2339                                         if (rv)
2340                                                 mddev->bitmap_info.offset = 0;
2341                                 }
2342                                 if (rv) {
2343                                         md_bitmap_destroy(mddev);
2344                                         mddev_resume(mddev);
2345                                         goto out;
2346                                 }
2347                                 mddev_resume(mddev);
2348                         }
2349                 }
2350         }
2351         if (!mddev->external) {
2352                 /* Ensure new bitmap info is stored in
2353                  * metadata promptly.
2354                  */
2355                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
2356                 md_wakeup_thread(mddev->thread);
2357         }
2358         rv = 0;
2359 out:
2360         mddev_unlock(mddev);
2361         if (rv)
2362                 return rv;
2363         return len;
2364 }
2365
2366 static struct md_sysfs_entry bitmap_location =
2367 __ATTR(location, S_IRUGO|S_IWUSR, location_show, location_store);
2368
2369 /* 'bitmap/space' is the space available at 'location' for the
2370  * bitmap.  This allows the kernel to know when it is safe to
2371  * resize the bitmap to match a resized array.
2372  */
2373 static ssize_t
2374 space_show(struct mddev *mddev, char *page)
2375 {
2376         return sprintf(page, "%lu\n", mddev->bitmap_info.space);
2377 }
2378
2379 static ssize_t
2380 space_store(struct mddev *mddev, const char *buf, size_t len)
2381 {
2382         unsigned long sectors;
2383         int rv;
2384
2385         rv = kstrtoul(buf, 10, &sectors);
2386         if (rv)
2387                 return rv;
2388
2389         if (sectors == 0)
2390                 return -EINVAL;
2391
2392         if (mddev->bitmap &&
2393             sectors < (mddev->bitmap->storage.bytes + 511) >> 9)
2394                 return -EFBIG; /* Bitmap is too big for this small space */
2395
2396         /* could make sure it isn't too big, but that isn't really
2397          * needed - user-space should be careful.
2398          */
2399         mddev->bitmap_info.space = sectors;
2400         return len;
2401 }
2402
2403 static struct md_sysfs_entry bitmap_space =
2404 __ATTR(space, S_IRUGO|S_IWUSR, space_show, space_store);
2405
2406 static ssize_t
2407 timeout_show(struct mddev *mddev, char *page)
2408 {
2409         ssize_t len;
2410         unsigned long secs = mddev->bitmap_info.daemon_sleep / HZ;
2411         unsigned long jifs = mddev->bitmap_info.daemon_sleep % HZ;
2412
2413         len = sprintf(page, "%lu", secs);
2414         if (jifs)
2415                 len += sprintf(page+len, ".%03u", jiffies_to_msecs(jifs));
2416         len += sprintf(page+len, "\n");
2417         return len;
2418 }
2419
2420 static ssize_t
2421 timeout_store(struct mddev *mddev, const char *buf, size_t len)
2422 {
2423         /* timeout can be set at any time */
2424         unsigned long timeout;
2425         int rv = strict_strtoul_scaled(buf, &timeout, 4);
2426         if (rv)
2427                 return rv;
2428
2429         /* just to make sure we don't overflow... */
2430         if (timeout >= LONG_MAX / HZ)
2431                 return -EINVAL;
2432
2433         timeout = timeout * HZ / 10000;
2434
2435         if (timeout >= MAX_SCHEDULE_TIMEOUT)
2436                 timeout = MAX_SCHEDULE_TIMEOUT-1;
2437         if (timeout < 1)
2438                 timeout = 1;
2439         mddev->bitmap_info.daemon_sleep = timeout;
2440         if (mddev->thread) {
2441                 /* if thread->timeout is MAX_SCHEDULE_TIMEOUT, then
2442                  * the bitmap is all clean and we don't need to
2443                  * adjust the timeout right now
2444                  */
2445                 if (mddev->thread->timeout < MAX_SCHEDULE_TIMEOUT) {
2446                         mddev->thread->timeout = timeout;
2447                         md_wakeup_thread(mddev->thread);
2448                 }
2449         }
2450         return len;
2451 }
2452
2453 static struct md_sysfs_entry bitmap_timeout =
2454 __ATTR(time_base, S_IRUGO|S_IWUSR, timeout_show, timeout_store);
2455
2456 static ssize_t
2457 backlog_show(struct mddev *mddev, char *page)
2458 {
2459         return sprintf(page, "%lu\n", mddev->bitmap_info.max_write_behind);
2460 }
2461
2462 static ssize_t
2463 backlog_store(struct mddev *mddev, const char *buf, size_t len)
2464 {
2465         unsigned long backlog;
2466         unsigned long old_mwb = mddev->bitmap_info.max_write_behind;
2467         int rv = kstrtoul(buf, 10, &backlog);
2468         if (rv)
2469                 return rv;
2470         if (backlog > COUNTER_MAX)
2471                 return -EINVAL;
2472         mddev->bitmap_info.max_write_behind = backlog;
2473         if (!backlog && mddev->serial_info_pool) {
2474                 /* serial_info_pool is not needed if backlog is zero */
2475                 if (!mddev->serialize_policy)
2476                         mddev_destroy_serial_pool(mddev, NULL, false);
2477         } else if (backlog && !mddev->serial_info_pool) {
2478                 /* serial_info_pool is needed since backlog is not zero */
2479                 struct md_rdev *rdev;
2480
2481                 rdev_for_each(rdev, mddev)
2482                         mddev_create_serial_pool(mddev, rdev, false);
2483         }
2484         if (old_mwb != backlog)
2485                 md_bitmap_update_sb(mddev->bitmap);
2486         return len;
2487 }
2488
2489 static struct md_sysfs_entry bitmap_backlog =
2490 __ATTR(backlog, S_IRUGO|S_IWUSR, backlog_show, backlog_store);
2491
2492 static ssize_t
2493 chunksize_show(struct mddev *mddev, char *page)
2494 {
2495         return sprintf(page, "%lu\n", mddev->bitmap_info.chunksize);
2496 }
2497
2498 static ssize_t
2499 chunksize_store(struct mddev *mddev, const char *buf, size_t len)
2500 {
2501         /* Can only be changed when no bitmap is active */
2502         int rv;
2503         unsigned long csize;
2504         if (mddev->bitmap)
2505                 return -EBUSY;
2506         rv = kstrtoul(buf, 10, &csize);
2507         if (rv)
2508                 return rv;
2509         if (csize < 512 ||
2510             !is_power_of_2(csize))
2511                 return -EINVAL;
2512         mddev->bitmap_info.chunksize = csize;
2513         return len;
2514 }
2515
2516 static struct md_sysfs_entry bitmap_chunksize =
2517 __ATTR(chunksize, S_IRUGO|S_IWUSR, chunksize_show, chunksize_store);
2518
2519 static ssize_t metadata_show(struct mddev *mddev, char *page)
2520 {
2521         if (mddev_is_clustered(mddev))
2522                 return sprintf(page, "clustered\n");
2523         return sprintf(page, "%s\n", (mddev->bitmap_info.external
2524                                       ? "external" : "internal"));
2525 }
2526
2527 static ssize_t metadata_store(struct mddev *mddev, const char *buf, size_t len)
2528 {
2529         if (mddev->bitmap ||
2530             mddev->bitmap_info.file ||
2531             mddev->bitmap_info.offset)
2532                 return -EBUSY;
2533         if (strncmp(buf, "external", 8) == 0)
2534                 mddev->bitmap_info.external = 1;
2535         else if ((strncmp(buf, "internal", 8) == 0) ||
2536                         (strncmp(buf, "clustered", 9) == 0))
2537                 mddev->bitmap_info.external = 0;
2538         else
2539                 return -EINVAL;
2540         return len;
2541 }
2542
2543 static struct md_sysfs_entry bitmap_metadata =
2544 __ATTR(metadata, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
2545
2546 static ssize_t can_clear_show(struct mddev *mddev, char *page)
2547 {
2548         int len;
2549         spin_lock(&mddev->lock);
2550         if (mddev->bitmap)
2551                 len = sprintf(page, "%s\n", (mddev->bitmap->need_sync ?
2552                                              "false" : "true"));
2553         else
2554                 len = sprintf(page, "\n");
2555         spin_unlock(&mddev->lock);
2556         return len;
2557 }
2558
2559 static ssize_t can_clear_store(struct mddev *mddev, const char *buf, size_t len)
2560 {
2561         if (mddev->bitmap == NULL)
2562                 return -ENOENT;
2563         if (strncmp(buf, "false", 5) == 0)
2564                 mddev->bitmap->need_sync = 1;
2565         else if (strncmp(buf, "true", 4) == 0) {
2566                 if (mddev->degraded)
2567                         return -EBUSY;
2568                 mddev->bitmap->need_sync = 0;
2569         } else
2570                 return -EINVAL;
2571         return len;
2572 }
2573
2574 static struct md_sysfs_entry bitmap_can_clear =
2575 __ATTR(can_clear, S_IRUGO|S_IWUSR, can_clear_show, can_clear_store);
2576
2577 static ssize_t
2578 behind_writes_used_show(struct mddev *mddev, char *page)
2579 {
2580         ssize_t ret;
2581         spin_lock(&mddev->lock);
2582         if (mddev->bitmap == NULL)
2583                 ret = sprintf(page, "0\n");
2584         else
2585                 ret = sprintf(page, "%lu\n",
2586                               mddev->bitmap->behind_writes_used);
2587         spin_unlock(&mddev->lock);
2588         return ret;
2589 }
2590
2591 static ssize_t
2592 behind_writes_used_reset(struct mddev *mddev, const char *buf, size_t len)
2593 {
2594         if (mddev->bitmap)
2595                 mddev->bitmap->behind_writes_used = 0;
2596         return len;
2597 }
2598
2599 static struct md_sysfs_entry max_backlog_used =
2600 __ATTR(max_backlog_used, S_IRUGO | S_IWUSR,
2601        behind_writes_used_show, behind_writes_used_reset);
2602
2603 static struct attribute *md_bitmap_attrs[] = {
2604         &bitmap_location.attr,
2605         &bitmap_space.attr,
2606         &bitmap_timeout.attr,
2607         &bitmap_backlog.attr,
2608         &bitmap_chunksize.attr,
2609         &bitmap_metadata.attr,
2610         &bitmap_can_clear.attr,
2611         &max_backlog_used.attr,
2612         NULL
2613 };
2614 struct attribute_group md_bitmap_group = {
2615         .name = "bitmap",
2616         .attrs = md_bitmap_attrs,
2617 };
2618