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 /* copied from buffer.c */
 328 static void
 329 __clear_page_buffers(struct page *page)
 330 {
 331         ClearPagePrivate(page);
 332         set_page_private(page, 0);
 333         put_page(page);
 334 }
 335 static void free_buffers(struct page *page)
 336 {
 337         struct buffer_head *bh;
 338
 339         if (!PagePrivate(page))
 340                 return;
 341
 342         bh = page_buffers(page);
 343         while (bh) {
 344                 struct buffer_head *next = bh->b_this_page;
 345                 free_buffer_head(bh);
 346                 bh = next;
 347         }
 348         __clear_page_buffers(page);
 349         put_page(page);
 350 }
 351
 352 /* read a page from a file.
 353  * We both read the page, and attach buffers to the page to record the
 354  * address of each block (using bmap).  These addresses will be used
 355  * to write the block later, completely bypassing the filesystem.
 356  * This usage is similar to how swap files are handled, and allows us
 357  * to write to a file with no concerns of memory allocation failing.
 358  */
 359 static int read_page(struct file *file, unsigned long index,
 360                      struct bitmap *bitmap,
 361                      unsigned long count,
 362                      struct page *page)
 363 {
 364         int ret = 0;
 365         struct inode *inode = file_inode(file);
 366         struct buffer_head *bh;
 367         sector_t block, blk_cur;
 368
 369         pr_debug("read bitmap file (%dB @ %llu)\n", (int)PAGE_SIZE,
 370                  (unsigned long long)index << PAGE_SHIFT);
 371
 372         bh = alloc_page_buffers(page, 1<<inode->i_blkbits, false);
 373         if (!bh) {
 374                 ret = -ENOMEM;
 375                 goto out;
 376         }
 377         attach_page_buffers(page, bh);
 378         blk_cur = index << (PAGE_SHIFT - inode->i_blkbits);
 379         while (bh) {
 380                 block = blk_cur;
 381
 382                 if (count == 0)
 383                         bh->b_blocknr = 0;
 384                 else {
 385                         ret = bmap(inode, &block);
 386                         if (ret || !block) {
 387                                 ret = -EINVAL;
 388                                 bh->b_blocknr = 0;
 389                                 goto out;
 390                         }
 391
 392                         bh->b_blocknr = block;
 393                         bh->b_bdev = inode->i_sb->s_bdev;
 394                         if (count < (1<<inode->i_blkbits))
 395                                 count = 0;
 396                         else
 397                                 count -= (1<<inode->i_blkbits);
 398
 399                         bh->b_end_io = end_bitmap_write;
 400                         bh->b_private = bitmap;
 401                         atomic_inc(&bitmap->pending_writes);
 402                         set_buffer_locked(bh);
 403                         set_buffer_mapped(bh);
 404                         submit_bh(REQ_OP_READ, 0, bh);
 405                 }
 406                 blk_cur++;
 407                 bh = bh->b_this_page;
 408         }
 409         page->index = index;
 410
 411         wait_event(bitmap->write_wait,
 412                    atomic_read(&bitmap->pending_writes)==0);
 413         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
 414                 ret = -EIO;
 415 out:
 416         if (ret)
 417                 pr_err("md: bitmap read error: (%dB @ %llu): %d\n",
 418                        (int)PAGE_SIZE,
 419                        (unsigned long long)index << PAGE_SHIFT,
 420                        ret);
 421         return ret;
 422 }
 423
 424 /*
 425  * bitmap file superblock operations
 426  */
 427
 428 /*
 429  * md_bitmap_wait_writes() should be called before writing any bitmap
 430  * blocks, to ensure previous writes, particularly from
 431  * md_bitmap_daemon_work(), have completed.
 432  */
 433 static void md_bitmap_wait_writes(struct bitmap *bitmap)
 434 {
 435         if (bitmap->storage.file)
 436                 wait_event(bitmap->write_wait,
 437                            atomic_read(&bitmap->pending_writes)==0);
 438         else
 439                 /* Note that we ignore the return value.  The writes
 440                  * might have failed, but that would just mean that
 441                  * some bits which should be cleared haven't been,
 442                  * which is safe.  The relevant bitmap blocks will
 443                  * probably get written again, but there is no great
 444                  * loss if they aren't.
 445                  */
 446                 md_super_wait(bitmap->mddev);
 447 }
 448
 449
 450 /* update the event counter and sync the superblock to disk */
 451 void md_bitmap_update_sb(struct bitmap *bitmap)
 452 {
 453         bitmap_super_t *sb;
 454
 455         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
 456                 return;
 457         if (bitmap->mddev->bitmap_info.external)
 458                 return;
 459         if (!bitmap->storage.sb_page) /* no superblock */
 460                 return;
 461         sb = kmap_atomic(bitmap->storage.sb_page);
 462         sb->events = cpu_to_le64(bitmap->mddev->events);
 463         if (bitmap->mddev->events < bitmap->events_cleared)
 464                 /* rocking back to read-only */
 465                 bitmap->events_cleared = bitmap->mddev->events;
 466         sb->events_cleared = cpu_to_le64(bitmap->events_cleared);
 467         /*
 468          * clear BITMAP_WRITE_ERROR bit to protect against the case that
 469          * a bitmap write error occurred but the later writes succeeded.
 470          */
 471         sb->state = cpu_to_le32(bitmap->flags & ~BIT(BITMAP_WRITE_ERROR));
 472         /* Just in case these have been changed via sysfs: */
 473         sb->daemon_sleep = cpu_to_le32(bitmap->mddev->bitmap_info.daemon_sleep/HZ);
 474         sb->write_behind = cpu_to_le32(bitmap->mddev->bitmap_info.max_write_behind);
 475         /* This might have been changed by a reshape */
 476         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 477         sb->chunksize = cpu_to_le32(bitmap->mddev->bitmap_info.chunksize);
 478         sb->nodes = cpu_to_le32(bitmap->mddev->bitmap_info.nodes);
 479         sb->sectors_reserved = cpu_to_le32(bitmap->mddev->
 480                                            bitmap_info.space);
 481         kunmap_atomic(sb);
 482         write_page(bitmap, bitmap->storage.sb_page, 1);
 483 }
 484 EXPORT_SYMBOL(md_bitmap_update_sb);
 485
 486 /* print out the bitmap file superblock */
 487 void md_bitmap_print_sb(struct bitmap *bitmap)
 488 {
 489         bitmap_super_t *sb;
 490
 491         if (!bitmap || !bitmap->storage.sb_page)
 492                 return;
 493         sb = kmap_atomic(bitmap->storage.sb_page);
 494         pr_debug("%s: bitmap file superblock:\n", bmname(bitmap));
 495         pr_debug("         magic: %08x\n", le32_to_cpu(sb->magic));
 496         pr_debug("       version: %d\n", le32_to_cpu(sb->version));
 497         pr_debug("          uuid: %08x.%08x.%08x.%08x\n",
 498                  le32_to_cpu(*(__le32 *)(sb->uuid+0)),
 499                  le32_to_cpu(*(__le32 *)(sb->uuid+4)),
 500                  le32_to_cpu(*(__le32 *)(sb->uuid+8)),
 501                  le32_to_cpu(*(__le32 *)(sb->uuid+12)));
 502         pr_debug("        events: %llu\n",
 503                  (unsigned long long) le64_to_cpu(sb->events));
 504         pr_debug("events cleared: %llu\n",
 505                  (unsigned long long) le64_to_cpu(sb->events_cleared));
 506         pr_debug("         state: %08x\n", le32_to_cpu(sb->state));
 507         pr_debug("     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
 508         pr_debug("  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
 509         pr_debug("     sync size: %llu KB\n",
 510                  (unsigned long long)le64_to_cpu(sb->sync_size)/2);
 511         pr_debug("max write behind: %d\n", le32_to_cpu(sb->write_behind));
 512         kunmap_atomic(sb);
 513 }
 514
 515 /*
 516  * bitmap_new_disk_sb
 517  * @bitmap
 518  *
 519  * This function is somewhat the reverse of bitmap_read_sb.  bitmap_read_sb
 520  * reads and verifies the on-disk bitmap superblock and populates bitmap_info.
 521  * This function verifies 'bitmap_info' and populates the on-disk bitmap
 522  * structure, which is to be written to disk.
 523  *
 524  * Returns: 0 on success, -Exxx on error
 525  */
 526 static int md_bitmap_new_disk_sb(struct bitmap *bitmap)
 527 {
 528         bitmap_super_t *sb;
 529         unsigned long chunksize, daemon_sleep, write_behind;
 530
 531         bitmap->storage.sb_page = alloc_page(GFP_KERNEL | __GFP_ZERO);
 532         if (bitmap->storage.sb_page == NULL)
 533                 return -ENOMEM;
 534         bitmap->storage.sb_page->index = 0;
 535
 536         sb = kmap_atomic(bitmap->storage.sb_page);
 537
 538         sb->magic = cpu_to_le32(BITMAP_MAGIC);
 539         sb->version = cpu_to_le32(BITMAP_MAJOR_HI);
 540
 541         chunksize = bitmap->mddev->bitmap_info.chunksize;
 542         BUG_ON(!chunksize);
 543         if (!is_power_of_2(chunksize)) {
 544                 kunmap_atomic(sb);
 545                 pr_warn("bitmap chunksize not a power of 2\n");
 546                 return -EINVAL;
 547         }
 548         sb->chunksize = cpu_to_le32(chunksize);
 549
 550         daemon_sleep = bitmap->mddev->bitmap_info.daemon_sleep;
 551         if (!daemon_sleep || (daemon_sleep > MAX_SCHEDULE_TIMEOUT)) {
 552                 pr_debug("Choosing daemon_sleep default (5 sec)\n");
 553                 daemon_sleep = 5 * HZ;
 554         }
 555         sb->daemon_sleep = cpu_to_le32(daemon_sleep);
 556         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 557
 558         /*
 559          * FIXME: write_behind for RAID1.  If not specified, what
 560          * is a good choice?  We choose COUNTER_MAX / 2 arbitrarily.
 561          */
 562         write_behind = bitmap->mddev->bitmap_info.max_write_behind;
 563         if (write_behind > COUNTER_MAX)
 564                 write_behind = COUNTER_MAX / 2;
 565         sb->write_behind = cpu_to_le32(write_behind);
 566         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 567
 568         /* keep the array size field of the bitmap superblock up to date */
 569         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 570
 571         memcpy(sb->uuid, bitmap->mddev->uuid, 16);
 572
 573         set_bit(BITMAP_STALE, &bitmap->flags);
 574         sb->state = cpu_to_le32(bitmap->flags);
 575         bitmap->events_cleared = bitmap->mddev->events;
 576         sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
 577         bitmap->mddev->bitmap_info.nodes = 0;
 578
 579         kunmap_atomic(sb);
 580
 581         return 0;
 582 }
 583
 584 /* read the superblock from the bitmap file and initialize some bitmap fields */
 585 static int md_bitmap_read_sb(struct bitmap *bitmap)
 586 {
 587         char *reason = NULL;
 588         bitmap_super_t *sb;
 589         unsigned long chunksize, daemon_sleep, write_behind;
 590         unsigned long long events;
 591         int nodes = 0;
 592         unsigned long sectors_reserved = 0;
 593         int err = -EINVAL;
 594         struct page *sb_page;
 595         loff_t offset = bitmap->mddev->bitmap_info.offset;
 596
 597         if (!bitmap->storage.file && !bitmap->mddev->bitmap_info.offset) {
 598                 chunksize = 128 * 1024 * 1024;
 599                 daemon_sleep = 5 * HZ;
 600                 write_behind = 0;
 601                 set_bit(BITMAP_STALE, &bitmap->flags);
 602                 err = 0;
 603                 goto out_no_sb;
 604         }
 605         /* page 0 is the superblock, read it... */
 606         sb_page = alloc_page(GFP_KERNEL);
 607         if (!sb_page)
 608                 return -ENOMEM;
 609         bitmap->storage.sb_page = sb_page;
 610
 611 re_read:
 612         /* If cluster_slot is set, the cluster is setup */
 613         if (bitmap->cluster_slot >= 0) {
 614                 sector_t bm_blocks = bitmap->mddev->resync_max_sectors;
 615
 616                 sector_div(bm_blocks,
 617                            bitmap->mddev->bitmap_info.chunksize >> 9);
 618                 /* bits to bytes */
 619                 bm_blocks = ((bm_blocks+7) >> 3) + sizeof(bitmap_super_t);
 620                 /* to 4k blocks */
 621                 bm_blocks = DIV_ROUND_UP_SECTOR_T(bm_blocks, 4096);
 622                 offset = bitmap->mddev->bitmap_info.offset + (bitmap->cluster_slot * (bm_blocks << 3));
 623                 pr_debug("%s:%d bm slot: %d offset: %llu\n", __func__, __LINE__,
 624                         bitmap->cluster_slot, offset);
 625         }
 626
 627         if (bitmap->storage.file) {
 628                 loff_t isize = i_size_read(bitmap->storage.file->f_mapping->host);
 629                 int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
 630
 631                 err = read_page(bitmap->storage.file, 0,
 632                                 bitmap, bytes, sb_page);
 633         } else {
 634                 err = read_sb_page(bitmap->mddev,
 635                                    offset,
 636                                    sb_page,
 637                                    0, sizeof(bitmap_super_t));
 638         }
 639         if (err)
 640                 return err;
 641
 642         err = -EINVAL;
 643         sb = kmap_atomic(sb_page);
 644
 645         chunksize = le32_to_cpu(sb->chunksize);
 646         daemon_sleep = le32_to_cpu(sb->daemon_sleep) * HZ;
 647         write_behind = le32_to_cpu(sb->write_behind);
 648         sectors_reserved = le32_to_cpu(sb->sectors_reserved);
 649         /* Setup nodes/clustername only if bitmap version is
 650          * cluster-compatible
 651          */
 652         if (sb->version == cpu_to_le32(BITMAP_MAJOR_CLUSTERED)) {
 653                 nodes = le32_to_cpu(sb->nodes);
 654                 strlcpy(bitmap->mddev->bitmap_info.cluster_name,
 655                                 sb->cluster_name, 64);
 656         }
 657
 658         /* verify that the bitmap-specific fields are valid */
 659         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
 660                 reason = "bad magic";
 661         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
 662                  le32_to_cpu(sb->version) > BITMAP_MAJOR_CLUSTERED)
 663                 reason = "unrecognized superblock version";
 664         else if (chunksize < 512)
 665                 reason = "bitmap chunksize too small";
 666         else if (!is_power_of_2(chunksize))
 667                 reason = "bitmap chunksize not a power of 2";
 668         else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT)
 669                 reason = "daemon sleep period out of range";
 670         else if (write_behind > COUNTER_MAX)
 671                 reason = "write-behind limit out of range (0 - 16383)";
 672         if (reason) {
 673                 pr_warn("%s: invalid bitmap file superblock: %s\n",
 674                         bmname(bitmap), reason);
 675                 goto out;
 676         }
 677
 678         /* keep the array size field of the bitmap superblock up to date */
 679         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 680
 681         if (bitmap->mddev->persistent) {
 682                 /*
 683                  * We have a persistent array superblock, so compare the
 684                  * bitmap's UUID and event counter to the mddev's
 685                  */
 686                 if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
 687                         pr_warn("%s: bitmap superblock UUID mismatch\n",
 688                                 bmname(bitmap));
 689                         goto out;
 690                 }
 691                 events = le64_to_cpu(sb->events);
 692                 if (!nodes && (events < bitmap->mddev->events)) {
 693                         pr_warn("%s: bitmap file is out of date (%llu < %llu) -- forcing full recovery\n",
 694                                 bmname(bitmap), events,
 695                                 (unsigned long long) bitmap->mddev->events);
 696                         set_bit(BITMAP_STALE, &bitmap->flags);
 697                 }
 698         }
 699
 700         /* assign fields using values from superblock */
 701         bitmap->flags |= le32_to_cpu(sb->state);
 702         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
 703                 set_bit(BITMAP_HOSTENDIAN, &bitmap->flags);
 704         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
 705         strlcpy(bitmap->mddev->bitmap_info.cluster_name, sb->cluster_name, 64);
 706         err = 0;
 707
 708 out:
 709         kunmap_atomic(sb);
 710         /* Assigning chunksize is required for "re_read" */
 711         bitmap->mddev->bitmap_info.chunksize = chunksize;
 712         if (err == 0 && nodes && (bitmap->cluster_slot < 0)) {
 713                 err = md_setup_cluster(bitmap->mddev, nodes);
 714                 if (err) {
 715                         pr_warn("%s: Could not setup cluster service (%d)\n",
 716                                 bmname(bitmap), err);
 717                         goto out_no_sb;
 718                 }
 719                 bitmap->cluster_slot = md_cluster_ops->slot_number(bitmap->mddev);
 720                 goto re_read;
 721         }
 722
 723
 724 out_no_sb:
 725         if (test_bit(BITMAP_STALE, &bitmap->flags))
 726                 bitmap->events_cleared = bitmap->mddev->events;
 727         bitmap->mddev->bitmap_info.chunksize = chunksize;
 728         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 729         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 730         bitmap->mddev->bitmap_info.nodes = nodes;
 731         if (bitmap->mddev->bitmap_info.space == 0 ||
 732             bitmap->mddev->bitmap_info.space > sectors_reserved)
 733                 bitmap->mddev->bitmap_info.space = sectors_reserved;
 734         if (err) {
 735                 md_bitmap_print_sb(bitmap);
 736                 if (bitmap->cluster_slot < 0)
 737                         md_cluster_stop(bitmap->mddev);
 738         }
 739         return err;
 740 }
 741
 742 /*
 743  * general bitmap file operations
 744  */
 745
 746 /*
 747  * on-disk bitmap:
 748  *
 749  * Use one bit per "chunk" (block set). We do the disk I/O on the bitmap
 750  * file a page at a time. There's a superblock at the start of the file.
 751  */
 752 /* calculate the index of the page that contains this bit */
 753 static inline unsigned long file_page_index(struct bitmap_storage *store,
 754                                             unsigned long chunk)
 755 {
 756         if (store->sb_page)
 757                 chunk += sizeof(bitmap_super_t) << 3;
 758         return chunk >> PAGE_BIT_SHIFT;
 759 }
 760
 761 /* calculate the (bit) offset of this bit within a page */
 762 static inline unsigned long file_page_offset(struct bitmap_storage *store,
 763                                              unsigned long chunk)
 764 {
 765         if (store->sb_page)
 766                 chunk += sizeof(bitmap_super_t) << 3;
 767         return chunk & (PAGE_BITS - 1);
 768 }
 769
 770 /*
 771  * return a pointer to the page in the filemap that contains the given bit
 772  *
 773  */
 774 static inline struct page *filemap_get_page(struct bitmap_storage *store,
 775                                             unsigned long chunk)
 776 {
 777         if (file_page_index(store, chunk) >= store->file_pages)
 778                 return NULL;
 779         return store->filemap[file_page_index(store, chunk)];
 780 }
 781
 782 static int md_bitmap_storage_alloc(struct bitmap_storage *store,
 783                                    unsigned long chunks, int with_super,
 784                                    int slot_number)
 785 {
 786         int pnum, offset = 0;
 787         unsigned long num_pages;
 788         unsigned long bytes;
 789
 790         bytes = DIV_ROUND_UP(chunks, 8);
 791         if (with_super)
 792                 bytes += sizeof(bitmap_super_t);
 793
 794         num_pages = DIV_ROUND_UP(bytes, PAGE_SIZE);
 795         offset = slot_number * num_pages;
 796
 797         store->filemap = kmalloc_array(num_pages, sizeof(struct page *),
 798                                        GFP_KERNEL);
 799         if (!store->filemap)
 800                 return -ENOMEM;
 801
 802         if (with_super && !store->sb_page) {
 803                 store->sb_page = alloc_page(GFP_KERNEL|__GFP_ZERO);
 804                 if (store->sb_page == NULL)
 805                         return -ENOMEM;
 806         }
 807
 808         pnum = 0;
 809         if (store->sb_page) {
 810                 store->filemap[0] = store->sb_page;
 811                 pnum = 1;
 812                 store->sb_page->index = offset;
 813         }
 814
 815         for ( ; pnum < num_pages; pnum++) {
 816                 store->filemap[pnum] = alloc_page(GFP_KERNEL|__GFP_ZERO);
 817                 if (!store->filemap[pnum]) {
 818                         store->file_pages = pnum;
 819                         return -ENOMEM;
 820                 }
 821                 store->filemap[pnum]->index = pnum + offset;
 822         }
 823         store->file_pages = pnum;
 824
 825         /* We need 4 bits per page, rounded up to a multiple
 826          * of sizeof(unsigned long) */
 827         store->filemap_attr = kzalloc(
 828                 roundup(DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
 829                 GFP_KERNEL);
 830         if (!store->filemap_attr)
 831                 return -ENOMEM;
 832
 833         store->bytes = bytes;
 834
 835         return 0;
 836 }
 837
 838 static void md_bitmap_file_unmap(struct bitmap_storage *store)
 839 {
 840         struct page **map, *sb_page;
 841         int pages;
 842         struct file *file;
 843
 844         file = store->file;
 845         map = store->filemap;
 846         pages = store->file_pages;
 847         sb_page = store->sb_page;
 848
 849         while (pages--)
 850                 if (map[pages] != sb_page) /* 0 is sb_page, release it below */
 851                         free_buffers(map[pages]);
 852         kfree(map);
 853         kfree(store->filemap_attr);
 854
 855         if (sb_page)
 856                 free_buffers(sb_page);
 857
 858         if (file) {
 859                 struct inode *inode = file_inode(file);
 860                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
 861                 fput(file);
 862         }
 863 }
 864
 865 /*
 866  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
 867  * then it is no longer reliable, so we stop using it and we mark the file
 868  * as failed in the superblock
 869  */
 870 static void md_bitmap_file_kick(struct bitmap *bitmap)
 871 {
 872         char *path, *ptr = NULL;
 873
 874         if (!test_and_set_bit(BITMAP_STALE, &bitmap->flags)) {
 875                 md_bitmap_update_sb(bitmap);
 876
 877                 if (bitmap->storage.file) {
 878                         path = kmalloc(PAGE_SIZE, GFP_KERNEL);
 879                         if (path)
 880                                 ptr = file_path(bitmap->storage.file,
 881                                              path, PAGE_SIZE);
 882
 883                         pr_warn("%s: kicking failed bitmap file %s from array!\n",
 884                                 bmname(bitmap), IS_ERR(ptr) ? "" : ptr);
 885
 886                         kfree(path);
 887                 } else
 888                         pr_warn("%s: disabling internal bitmap due to errors\n",
 889                                 bmname(bitmap));
 890         }
 891 }
 892
 893 enum bitmap_page_attr {
 894         BITMAP_PAGE_DIRTY = 0,     /* there are set bits that need to be synced */
 895         BITMAP_PAGE_PENDING = 1,   /* there are bits that are being cleaned.
 896                                     * i.e. counter is 1 or 2. */
 897         BITMAP_PAGE_NEEDWRITE = 2, /* there are cleared bits that need to be synced */
 898 };
 899
 900 static inline void set_page_attr(struct bitmap *bitmap, int pnum,
 901                                  enum bitmap_page_attr attr)
 902 {
 903         set_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 904 }
 905
 906 static inline void clear_page_attr(struct bitmap *bitmap, int pnum,
 907                                    enum bitmap_page_attr attr)
 908 {
 909         clear_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 910 }
 911
 912 static inline int test_page_attr(struct bitmap *bitmap, int pnum,
 913                                  enum bitmap_page_attr attr)
 914 {
 915         return test_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 916 }
 917
 918 static inline int test_and_clear_page_attr(struct bitmap *bitmap, int pnum,
 919                                            enum bitmap_page_attr attr)
 920 {
 921         return test_and_clear_bit((pnum<<2) + attr,
 922                                   bitmap->storage.filemap_attr);
 923 }
 924 /*
 925  * bitmap_file_set_bit -- called before performing a write to the md device
 926  * to set (and eventually sync) a particular bit in the bitmap file
 927  *
 928  * we set the bit immediately, then we record the page number so that
 929  * when an unplug occurs, we can flush the dirty pages out to disk
 930  */
 931 static void md_bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 932 {
 933         unsigned long bit;
 934         struct page *page;
 935         void *kaddr;
 936         unsigned long chunk = block >> bitmap->counts.chunkshift;
 937         struct bitmap_storage *store = &bitmap->storage;
 938         unsigned long node_offset = 0;
 939
 940         if (mddev_is_clustered(bitmap->mddev))
 941                 node_offset = bitmap->cluster_slot * store->file_pages;
 942
 943         page = filemap_get_page(&bitmap->storage, chunk);
 944         if (!page)
 945                 return;
 946         bit = file_page_offset(&bitmap->storage, chunk);
 947
 948         /* set the bit */
 949         kaddr = kmap_atomic(page);
 950         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
 951                 set_bit(bit, kaddr);
 952         else
 953                 set_bit_le(bit, kaddr);
 954         kunmap_atomic(kaddr);
 955         pr_debug("set file bit %lu page %lu\n", bit, page->index);
 956         /* record page number so it gets flushed to disk when unplug occurs */
 957         set_page_attr(bitmap, page->index - node_offset, BITMAP_PAGE_DIRTY);
 958 }
 959
 960 static void md_bitmap_file_clear_bit(struct bitmap *bitmap, sector_t block)
 961 {
 962         unsigned long bit;
 963         struct page *page;
 964         void *paddr;
 965         unsigned long chunk = block >> bitmap->counts.chunkshift;
 966         struct bitmap_storage *store = &bitmap->storage;
 967         unsigned long node_offset = 0;
 968
 969         if (mddev_is_clustered(bitmap->mddev))
 970                 node_offset = bitmap->cluster_slot * store->file_pages;
 971
 972         page = filemap_get_page(&bitmap->storage, chunk);
 973         if (!page)
 974                 return;
 975         bit = file_page_offset(&bitmap->storage, chunk);
 976         paddr = kmap_atomic(page);
 977         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
 978                 clear_bit(bit, paddr);
 979         else
 980                 clear_bit_le(bit, paddr);
 981         kunmap_atomic(paddr);
 982         if (!test_page_attr(bitmap, page->index - node_offset, BITMAP_PAGE_NEEDWRITE)) {
 983                 set_page_attr(bitmap, page->index - node_offset, BITMAP_PAGE_PENDING);
 984                 bitmap->allclean = 0;
 985         }
 986 }
 987
 988 static int md_bitmap_file_test_bit(struct bitmap *bitmap, sector_t block)
 989 {
 990         unsigned long bit;
 991         struct page *page;
 992         void *paddr;
 993         unsigned long chunk = block >> bitmap->counts.chunkshift;
 994         int set = 0;
 995
 996         page = filemap_get_page(&bitmap->storage, chunk);
 997         if (!page)
 998                 return -EINVAL;
 999         bit = file_page_offset(&bitmap->storage, chunk);
1000         paddr = kmap_atomic(page);
1001         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
1002                 set = test_bit(bit, paddr);
1003         else
1004                 set = test_bit_le(bit, paddr);
1005         kunmap_atomic(paddr);
1006         return set;
1007 }
1008
1009
1010 /* this gets called when the md device is ready to unplug its underlying
1011  * (slave) device queues -- before we let any writes go down, we need to
1012  * sync the dirty pages of the bitmap file to disk */
1013 void md_bitmap_unplug(struct bitmap *bitmap)
1014 {
1015         unsigned long i;
1016         int dirty, need_write;
1017         int writing = 0;
1018
1019         if (!bitmap || !bitmap->storage.filemap ||
1020             test_bit(BITMAP_STALE, &bitmap->flags))
1021                 return;
1022
1023         /* look at each page to see if there are any set bits that need to be
1024          * flushed out to disk */
1025         for (i = 0; i < bitmap->storage.file_pages; i++) {
1026                 dirty = test_and_clear_page_attr(bitmap, i, BITMAP_PAGE_DIRTY);
1027                 need_write = test_and_clear_page_attr(bitmap, i,
1028                                                       BITMAP_PAGE_NEEDWRITE);
1029                 if (dirty || need_write) {
1030                         if (!writing) {
1031                                 md_bitmap_wait_writes(bitmap);
1032                                 if (bitmap->mddev->queue)
1033                                         blk_add_trace_msg(bitmap->mddev->queue,
1034                                                           "md bitmap_unplug");
1035                         }
1036                         clear_page_attr(bitmap, i, BITMAP_PAGE_PENDING);
1037                         write_page(bitmap, bitmap->storage.filemap[i], 0);
1038                         writing = 1;
1039                 }
1040         }
1041         if (writing)
1042                 md_bitmap_wait_writes(bitmap);
1043
1044         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
1045                 md_bitmap_file_kick(bitmap);
1046 }
1047 EXPORT_SYMBOL(md_bitmap_unplug);
1048
1049 static void md_bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
1050 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
1051  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
1052  * memory mapping of the bitmap file
1053  * Special cases:
1054  *   if there's no bitmap file, or if the bitmap file had been
1055  *   previously kicked from the array, we mark all the bits as
1056  *   1's in order to cause a full resync.
1057  *
1058  * We ignore all bits for sectors that end earlier than 'start'.
1059  * This is used when reading an out-of-date bitmap...
1060  */
1061 static int md_bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
1062 {
1063         unsigned long i, chunks, index, oldindex, bit, node_offset = 0;
1064         struct page *page = NULL;
1065         unsigned long bit_cnt = 0;
1066         struct file *file;
1067         unsigned long offset;
1068         int outofdate;
1069         int ret = -ENOSPC;
1070         void *paddr;
1071         struct bitmap_storage *store = &bitmap->storage;
1072
1073         chunks = bitmap->counts.chunks;
1074         file = store->file;
1075
1076         if (!file && !bitmap->mddev->bitmap_info.offset) {
1077                 /* No permanent bitmap - fill with '1s'. */
1078                 store->filemap = NULL;
1079                 store->file_pages = 0;
1080                 for (i = 0; i < chunks ; i++) {
1081                         /* if the disk bit is set, set the memory bit */
1082                         int needed = ((sector_t)(i+1) << (bitmap->counts.chunkshift)
1083                                       >= start);
1084                         md_bitmap_set_memory_bits(bitmap,
1085                                                   (sector_t)i << bitmap->counts.chunkshift,
1086                                                   needed);
1087                 }
1088                 return 0;
1089         }
1090
1091         outofdate = test_bit(BITMAP_STALE, &bitmap->flags);
1092         if (outofdate)
1093                 pr_warn("%s: bitmap file is out of date, doing full recovery\n", bmname(bitmap));
1094
1095         if (file && i_size_read(file->f_mapping->host) < store->bytes) {
1096                 pr_warn("%s: bitmap file too short %lu < %lu\n",
1097                         bmname(bitmap),
1098                         (unsigned long) i_size_read(file->f_mapping->host),
1099                         store->bytes);
1100                 goto err;
1101         }
1102
1103         oldindex = ~0L;
1104         offset = 0;
1105         if (!bitmap->mddev->bitmap_info.external)
1106                 offset = sizeof(bitmap_super_t);
1107
1108         if (mddev_is_clustered(bitmap->mddev))
1109                 node_offset = bitmap->cluster_slot * (DIV_ROUND_UP(store->bytes, PAGE_SIZE));
1110
1111         for (i = 0; i < chunks; i++) {
1112                 int b;
1113                 index = file_page_index(&bitmap->storage, i);
1114                 bit = file_page_offset(&bitmap->storage, i);
1115                 if (index != oldindex) { /* this is a new page, read it in */
1116                         int count;
1117                         /* unmap the old page, we're done with it */
1118                         if (index == store->file_pages-1)
1119                                 count = store->bytes - index * PAGE_SIZE;
1120                         else
1121                                 count = PAGE_SIZE;
1122                         page = store->filemap[index];
1123                         if (file)
1124                                 ret = read_page(file, index, bitmap,
1125                                                 count, page);
1126                         else
1127                                 ret = read_sb_page(
1128                                         bitmap->mddev,
1129                                         bitmap->mddev->bitmap_info.offset,
1130                                         page,
1131                                         index + node_offset, count);
1132
1133                         if (ret)
1134                                 goto err;
1135
1136                         oldindex = index;
1137
1138                         if (outofdate) {
1139                                 /*
1140                                  * if bitmap is out of date, dirty the
1141                                  * whole page and write it out
1142                                  */
1143                                 paddr = kmap_atomic(page);
1144                                 memset(paddr + offset, 0xff,
1145                                        PAGE_SIZE - offset);
1146                                 kunmap_atomic(paddr);
1147                                 write_page(bitmap, page, 1);
1148
1149                                 ret = -EIO;
1150                                 if (test_bit(BITMAP_WRITE_ERROR,
1151                                              &bitmap->flags))
1152                                         goto err;
1153                         }
1154                 }
1155                 paddr = kmap_atomic(page);
1156                 if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
1157                         b = test_bit(bit, paddr);
1158                 else
1159                         b = test_bit_le(bit, paddr);
1160                 kunmap_atomic(paddr);
1161                 if (b) {
1162                         /* if the disk bit is set, set the memory bit */
1163                         int needed = ((sector_t)(i+1) << bitmap->counts.chunkshift
1164                                       >= start);
1165                         md_bitmap_set_memory_bits(bitmap,
1166                                                   (sector_t)i << bitmap->counts.chunkshift,
1167                                                   needed);
1168                         bit_cnt++;
1169                 }
1170                 offset = 0;
1171         }
1172
1173         pr_debug("%s: bitmap initialized from disk: read %lu pages, set %lu of %lu bits\n",
1174                  bmname(bitmap), store->file_pages,
1175                  bit_cnt, chunks);
1176
1177         return 0;
1178
1179  err:
1180         pr_warn("%s: bitmap initialisation failed: %d\n",
1181                 bmname(bitmap), ret);
1182         return ret;
1183 }
1184
1185 void md_bitmap_write_all(struct bitmap *bitmap)
1186 {
1187         /* We don't actually write all bitmap blocks here,
1188          * just flag them as needing to be written
1189          */
1190         int i;
1191
1192         if (!bitmap || !bitmap->storage.filemap)
1193                 return;
1194         if (bitmap->storage.file)
1195                 /* Only one copy, so nothing needed */
1196                 return;
1197
1198         for (i = 0; i < bitmap->storage.file_pages; i++)
1199                 set_page_attr(bitmap, i,
1200                               BITMAP_PAGE_NEEDWRITE);
1201         bitmap->allclean = 0;
1202 }
1203
1204 static void md_bitmap_count_page(struct bitmap_counts *bitmap,
1205                                  sector_t offset, int inc)
1206 {
1207         sector_t chunk = offset >> bitmap->chunkshift;
1208         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1209         bitmap->bp[page].count += inc;
1210         md_bitmap_checkfree(bitmap, page);
1211 }
1212
1213 static void md_bitmap_set_pending(struct bitmap_counts *bitmap, sector_t offset)
1214 {
1215         sector_t chunk = offset >> bitmap->chunkshift;
1216         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1217         struct bitmap_page *bp = &bitmap->bp[page];
1218
1219         if (!bp->pending)
1220                 bp->pending = 1;
1221 }
1222
1223 static bitmap_counter_t *md_bitmap_get_counter(struct bitmap_counts *bitmap,
1224                                                sector_t offset, sector_t *blocks,
1225                                                int create);
1226
1227 /*
1228  * bitmap daemon -- periodically wakes up to clean bits and flush pages
1229  *                      out to disk
1230  */
1231
1232 void md_bitmap_daemon_work(struct mddev *mddev)
1233 {
1234         struct bitmap *bitmap;
1235         unsigned long j;
1236         unsigned long nextpage;
1237         sector_t blocks;
1238         struct bitmap_counts *counts;
1239
1240         /* Use a mutex to guard daemon_work against
1241          * bitmap_destroy.
1242          */
1243         mutex_lock(&mddev->bitmap_info.mutex);
1244         bitmap = mddev->bitmap;
1245         if (bitmap == NULL) {
1246                 mutex_unlock(&mddev->bitmap_info.mutex);
1247                 return;
1248         }
1249         if (time_before(jiffies, bitmap->daemon_lastrun
1250                         + mddev->bitmap_info.daemon_sleep))
1251                 goto done;
1252
1253         bitmap->daemon_lastrun = jiffies;
1254         if (bitmap->allclean) {
1255                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1256                 goto done;
1257         }
1258         bitmap->allclean = 1;
1259
1260         if (bitmap->mddev->queue)
1261                 blk_add_trace_msg(bitmap->mddev->queue,
1262                                   "md bitmap_daemon_work");
1263
1264         /* Any file-page which is PENDING now needs to be written.
1265          * So set NEEDWRITE now, then after we make any last-minute changes
1266          * we will write it.
1267          */
1268         for (j = 0; j < bitmap->storage.file_pages; j++)
1269                 if (test_and_clear_page_attr(bitmap, j,
1270                                              BITMAP_PAGE_PENDING))
1271                         set_page_attr(bitmap, j,
1272                                       BITMAP_PAGE_NEEDWRITE);
1273
1274         if (bitmap->need_sync &&
1275             mddev->bitmap_info.external == 0) {
1276                 /* Arrange for superblock update as well as
1277                  * other changes */
1278                 bitmap_super_t *sb;
1279                 bitmap->need_sync = 0;
1280                 if (bitmap->storage.filemap) {
1281                         sb = kmap_atomic(bitmap->storage.sb_page);
1282                         sb->events_cleared =
1283                                 cpu_to_le64(bitmap->events_cleared);
1284                         kunmap_atomic(sb);
1285                         set_page_attr(bitmap, 0,
1286                                       BITMAP_PAGE_NEEDWRITE);
1287                 }
1288         }
1289         /* Now look at the bitmap counters and if any are '2' or '1',
1290          * decrement and handle accordingly.
1291          */
1292         counts = &bitmap->counts;
1293         spin_lock_irq(&counts->lock);
1294         nextpage = 0;
1295         for (j = 0; j < counts->chunks; j++) {
1296                 bitmap_counter_t *bmc;
1297                 sector_t  block = (sector_t)j << counts->chunkshift;
1298
1299                 if (j == nextpage) {
1300                         nextpage += PAGE_COUNTER_RATIO;
1301                         if (!counts->bp[j >> PAGE_COUNTER_SHIFT].pending) {
1302                                 j |= PAGE_COUNTER_MASK;
1303                                 continue;
1304                         }
1305                         counts->bp[j >> PAGE_COUNTER_SHIFT].pending = 0;
1306                 }
1307
1308                 bmc = md_bitmap_get_counter(counts, block, &blocks, 0);
1309                 if (!bmc) {
1310                         j |= PAGE_COUNTER_MASK;
1311                         continue;
1312                 }
1313                 if (*bmc == 1 && !bitmap->need_sync) {
1314                         /* We can clear the bit */
1315                         *bmc = 0;
1316                         md_bitmap_count_page(counts, block, -1);
1317                         md_bitmap_file_clear_bit(bitmap, block);
1318                 } else if (*bmc && *bmc <= 2) {
1319                         *bmc = 1;
1320                         md_bitmap_set_pending(counts, block);
1321                         bitmap->allclean = 0;
1322                 }
1323         }
1324         spin_unlock_irq(&counts->lock);
1325
1326         md_bitmap_wait_writes(bitmap);
1327         /* Now start writeout on any page in NEEDWRITE that isn't DIRTY.
1328          * DIRTY pages need to be written by bitmap_unplug so it can wait
1329          * for them.
1330          * If we find any DIRTY page we stop there and let bitmap_unplug
1331          * handle all the rest.  This is important in the case where
1332          * the first blocking holds the superblock and it has been updated.
1333          * We mustn't write any other blocks before the superblock.
1334          */
1335         for (j = 0;
1336              j < bitmap->storage.file_pages
1337                      && !test_bit(BITMAP_STALE, &bitmap->flags);
1338              j++) {
1339                 if (test_page_attr(bitmap, j,
1340                                    BITMAP_PAGE_DIRTY))
1341                         /* bitmap_unplug will handle the rest */
1342                         break;
1343                 if (bitmap->storage.filemap &&
1344                     test_and_clear_page_attr(bitmap, j,
1345                                              BITMAP_PAGE_NEEDWRITE)) {
1346                         write_page(bitmap, bitmap->storage.filemap[j], 0);
1347                 }
1348         }
1349
1350  done:
1351         if (bitmap->allclean == 0)
1352                 mddev->thread->timeout =
1353                         mddev->bitmap_info.daemon_sleep;
1354         mutex_unlock(&mddev->bitmap_info.mutex);
1355 }
1356
1357 static bitmap_counter_t *md_bitmap_get_counter(struct bitmap_counts *bitmap,
1358                                                sector_t offset, sector_t *blocks,
1359                                                int create)
1360 __releases(bitmap->lock)
1361 __acquires(bitmap->lock)
1362 {
1363         /* If 'create', we might release the lock and reclaim it.
1364          * The lock must have been taken with interrupts enabled.
1365          * If !create, we don't release the lock.
1366          */
1367         sector_t chunk = offset >> bitmap->chunkshift;
1368         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1369         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1370         sector_t csize;
1371         int err;
1372
1373         err = md_bitmap_checkpage(bitmap, page, create, 0);
1374
1375         if (bitmap->bp[page].hijacked ||
1376             bitmap->bp[page].map == NULL)
1377                 csize = ((sector_t)1) << (bitmap->chunkshift +
1378                                           PAGE_COUNTER_SHIFT - 1);
1379         else
1380                 csize = ((sector_t)1) << bitmap->chunkshift;
1381         *blocks = csize - (offset & (csize - 1));
1382
1383         if (err < 0)
1384                 return NULL;
1385
1386         /* now locked ... */
1387
1388         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1389                 /* should we use the first or second counter field
1390                  * of the hijacked pointer? */
1391                 int hi = (pageoff > PAGE_COUNTER_MASK);
1392                 return  &((bitmap_counter_t *)
1393                           &bitmap->bp[page].map)[hi];
1394         } else /* page is allocated */
1395                 return (bitmap_counter_t *)
1396                         &(bitmap->bp[page].map[pageoff]);
1397 }
1398
1399 int md_bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1400 {
1401         if (!bitmap)
1402                 return 0;
1403
1404         if (behind) {
1405                 int bw;
1406                 atomic_inc(&bitmap->behind_writes);
1407                 bw = atomic_read(&bitmap->behind_writes);
1408                 if (bw > bitmap->behind_writes_used)
1409                         bitmap->behind_writes_used = bw;
1410
1411                 pr_debug("inc write-behind count %d/%lu\n",
1412                          bw, bitmap->mddev->bitmap_info.max_write_behind);
1413         }
1414
1415         while (sectors) {
1416                 sector_t blocks;
1417                 bitmap_counter_t *bmc;
1418
1419                 spin_lock_irq(&bitmap->counts.lock);
1420                 bmc = md_bitmap_get_counter(&bitmap->counts, offset, &blocks, 1);
1421                 if (!bmc) {
1422                         spin_unlock_irq(&bitmap->counts.lock);
1423                         return 0;
1424                 }
1425
1426                 if (unlikely(COUNTER(*bmc) == COUNTER_MAX)) {
1427                         DEFINE_WAIT(__wait);
1428                         /* note that it is safe to do the prepare_to_wait
1429                          * after the test as long as we do it before dropping
1430                          * the spinlock.
1431                          */
1432                         prepare_to_wait(&bitmap->overflow_wait, &__wait,
1433                                         TASK_UNINTERRUPTIBLE);
1434                         spin_unlock_irq(&bitmap->counts.lock);
1435                         schedule();
1436                         finish_wait(&bitmap->overflow_wait, &__wait);
1437                         continue;
1438                 }
1439
1440                 switch (*bmc) {
1441                 case 0:
1442                         md_bitmap_file_set_bit(bitmap, offset);
1443                         md_bitmap_count_page(&bitmap->counts, offset, 1);
1444                         /* fall through */
1445                 case 1:
1446                         *bmc = 2;
1447                 }
1448
1449                 (*bmc)++;
1450
1451                 spin_unlock_irq(&bitmap->counts.lock);
1452
1453                 offset += blocks;
1454                 if (sectors > blocks)
1455                         sectors -= blocks;
1456                 else
1457                         sectors = 0;
1458         }
1459         return 0;
1460 }
1461 EXPORT_SYMBOL(md_bitmap_startwrite);
1462
1463 void md_bitmap_endwrite(struct bitmap *bitmap, sector_t offset,
1464                         unsigned long sectors, int success, int behind)
1465 {
1466         if (!bitmap)
1467                 return;
1468         if (behind) {
1469                 if (atomic_dec_and_test(&bitmap->behind_writes))
1470                         wake_up(&bitmap->behind_wait);
1471                 pr_debug("dec write-behind count %d/%lu\n",
1472                          atomic_read(&bitmap->behind_writes),
1473                          bitmap->mddev->bitmap_info.max_write_behind);
1474         }
1475
1476         while (sectors) {
1477                 sector_t blocks;
1478                 unsigned long flags;
1479                 bitmap_counter_t *bmc;
1480
1481                 spin_lock_irqsave(&bitmap->counts.lock, flags);
1482                 bmc = md_bitmap_get_counter(&bitmap->counts, offset, &blocks, 0);
1483                 if (!bmc) {
1484                         spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1485                         return;
1486                 }
1487
1488                 if (success && !bitmap->mddev->degraded &&
1489                     bitmap->events_cleared < bitmap->mddev->events) {
1490                         bitmap->events_cleared = bitmap->mddev->events;
1491                         bitmap->need_sync = 1;
1492                         sysfs_notify_dirent_safe(bitmap->sysfs_can_clear);
1493                 }
1494
1495                 if (!success && !NEEDED(*bmc))
1496                         *bmc |= NEEDED_MASK;
1497
1498                 if (COUNTER(*bmc) == COUNTER_MAX)
1499                         wake_up(&bitmap->overflow_wait);
1500
1501                 (*bmc)--;
1502                 if (*bmc <= 2) {
1503                         md_bitmap_set_pending(&bitmap->counts, offset);
1504                         bitmap->allclean = 0;
1505                 }
1506                 spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1507                 offset += blocks;
1508                 if (sectors > blocks)
1509                         sectors -= blocks;
1510                 else
1511                         sectors = 0;
1512         }
1513 }
1514 EXPORT_SYMBOL(md_bitmap_endwrite);
1515
1516 static int __bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1517                                int degraded)
1518 {
1519         bitmap_counter_t *bmc;
1520         int rv;
1521         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1522                 *blocks = 1024;
1523                 return 1; /* always resync if no bitmap */
1524         }
1525         spin_lock_irq(&bitmap->counts.lock);
1526         bmc = md_bitmap_get_counter(&bitmap->counts, offset, blocks, 0);
1527         rv = 0;
1528         if (bmc) {
1529                 /* locked */
1530                 if (RESYNC(*bmc))
1531                         rv = 1;
1532                 else if (NEEDED(*bmc)) {
1533                         rv = 1;
1534                         if (!degraded) { /* don't set/clear bits if degraded */
1535                                 *bmc |= RESYNC_MASK;
1536                                 *bmc &= ~NEEDED_MASK;
1537                         }
1538                 }
1539         }
1540         spin_unlock_irq(&bitmap->counts.lock);
1541         return rv;
1542 }
1543
1544 int md_bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1545                          int degraded)
1546 {
1547         /* bitmap_start_sync must always report on multiples of whole
1548          * pages, otherwise resync (which is very PAGE_SIZE based) will
1549          * get confused.
1550          * So call __bitmap_start_sync repeatedly (if needed) until
1551          * At least PAGE_SIZE>>9 blocks are covered.
1552          * Return the 'or' of the result.
1553          */
1554         int rv = 0;
1555         sector_t blocks1;
1556
1557         *blocks = 0;
1558         while (*blocks < (PAGE_SIZE>>9)) {
1559                 rv |= __bitmap_start_sync(bitmap, offset,
1560                                           &blocks1, degraded);
1561                 offset += blocks1;
1562                 *blocks += blocks1;
1563         }
1564         return rv;
1565 }
1566 EXPORT_SYMBOL(md_bitmap_start_sync);
1567
1568 void md_bitmap_end_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks, int aborted)
1569 {
1570         bitmap_counter_t *bmc;
1571         unsigned long flags;
1572
1573         if (bitmap == NULL) {
1574                 *blocks = 1024;
1575                 return;
1576         }
1577         spin_lock_irqsave(&bitmap->counts.lock, flags);
1578         bmc = md_bitmap_get_counter(&bitmap->counts, offset, blocks, 0);
1579         if (bmc == NULL)
1580                 goto unlock;
1581         /* locked */
1582         if (RESYNC(*bmc)) {
1583                 *bmc &= ~RESYNC_MASK;
1584
1585                 if (!NEEDED(*bmc) && aborted)
1586                         *bmc |= NEEDED_MASK;
1587                 else {
1588                         if (*bmc <= 2) {
1589                                 md_bitmap_set_pending(&bitmap->counts, offset);
1590                                 bitmap->allclean = 0;
1591                         }
1592                 }
1593         }
1594  unlock:
1595         spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1596 }
1597 EXPORT_SYMBOL(md_bitmap_end_sync);
1598
1599 void md_bitmap_close_sync(struct bitmap *bitmap)
1600 {
1601         /* Sync has finished, and any bitmap chunks that weren't synced
1602          * properly have been aborted.  It remains to us to clear the
1603          * RESYNC bit wherever it is still on
1604          */
1605         sector_t sector = 0;
1606         sector_t blocks;
1607         if (!bitmap)
1608                 return;
1609         while (sector < bitmap->mddev->resync_max_sectors) {
1610                 md_bitmap_end_sync(bitmap, sector, &blocks, 0);
1611                 sector += blocks;
1612         }
1613 }
1614 EXPORT_SYMBOL(md_bitmap_close_sync);
1615
1616 void md_bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector, bool force)
1617 {
1618         sector_t s = 0;
1619         sector_t blocks;
1620
1621         if (!bitmap)
1622                 return;
1623         if (sector == 0) {
1624                 bitmap->last_end_sync = jiffies;
1625                 return;
1626         }
1627         if (!force && time_before(jiffies, (bitmap->last_end_sync
1628                                   + bitmap->mddev->bitmap_info.daemon_sleep)))
1629                 return;
1630         wait_event(bitmap->mddev->recovery_wait,
1631                    atomic_read(&bitmap->mddev->recovery_active) == 0);
1632
1633         bitmap->mddev->curr_resync_completed = sector;
1634         set_bit(MD_SB_CHANGE_CLEAN, &bitmap->mddev->sb_flags);
1635         sector &= ~((1ULL << bitmap->counts.chunkshift) - 1);
1636         s = 0;
1637         while (s < sector && s < bitmap->mddev->resync_max_sectors) {
1638                 md_bitmap_end_sync(bitmap, s, &blocks, 0);
1639                 s += blocks;
1640         }
1641         bitmap->last_end_sync = jiffies;
1642         sysfs_notify(&bitmap->mddev->kobj, NULL, "sync_completed");
1643 }
1644 EXPORT_SYMBOL(md_bitmap_cond_end_sync);
1645
1646 void md_bitmap_sync_with_cluster(struct mddev *mddev,
1647                               sector_t old_lo, sector_t old_hi,
1648                               sector_t new_lo, sector_t new_hi)
1649 {
1650         struct bitmap *bitmap = mddev->bitmap;
1651         sector_t sector, blocks = 0;
1652
1653         for (sector = old_lo; sector < new_lo; ) {
1654                 md_bitmap_end_sync(bitmap, sector, &blocks, 0);
1655                 sector += blocks;
1656         }
1657         WARN((blocks > new_lo) && old_lo, "alignment is not correct for lo\n");
1658
1659         for (sector = old_hi; sector < new_hi; ) {
1660                 md_bitmap_start_sync(bitmap, sector, &blocks, 0);
1661                 sector += blocks;
1662         }
1663         WARN((blocks > new_hi) && old_hi, "alignment is not correct for hi\n");
1664 }
1665 EXPORT_SYMBOL(md_bitmap_sync_with_cluster);
1666
1667 static void md_bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1668 {
1669         /* For each chunk covered by any of these sectors, set the
1670          * counter to 2 and possibly set resync_needed.  They should all
1671          * be 0 at this point
1672          */
1673
1674         sector_t secs;
1675         bitmap_counter_t *bmc;
1676         spin_lock_irq(&bitmap->counts.lock);
1677         bmc = md_bitmap_get_counter(&bitmap->counts, offset, &secs, 1);
1678         if (!bmc) {
1679                 spin_unlock_irq(&bitmap->counts.lock);
1680                 return;
1681         }
1682         if (!*bmc) {
1683                 *bmc = 2;
1684                 md_bitmap_count_page(&bitmap->counts, offset, 1);
1685                 md_bitmap_set_pending(&bitmap->counts, offset);
1686                 bitmap->allclean = 0;
1687         }
1688         if (needed)
1689                 *bmc |= NEEDED_MASK;
1690         spin_unlock_irq(&bitmap->counts.lock);
1691 }
1692
1693 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
1694 void md_bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1695 {
1696         unsigned long chunk;
1697
1698         for (chunk = s; chunk <= e; chunk++) {
1699                 sector_t sec = (sector_t)chunk << bitmap->counts.chunkshift;
1700                 md_bitmap_set_memory_bits(bitmap, sec, 1);
1701                 md_bitmap_file_set_bit(bitmap, sec);
1702                 if (sec < bitmap->mddev->recovery_cp)
1703                         /* We are asserting that the array is dirty,
1704                          * so move the recovery_cp address back so
1705                          * that it is obvious that it is dirty
1706                          */
1707                         bitmap->mddev->recovery_cp = sec;
1708         }
1709 }
1710
1711 /*
1712  * flush out any pending updates
1713  */
1714 void md_bitmap_flush(struct mddev *mddev)
1715 {
1716         struct bitmap *bitmap = mddev->bitmap;
1717         long sleep;
1718
1719         if (!bitmap) /* there was no bitmap */
1720                 return;
1721
1722         /* run the daemon_work three time to ensure everything is flushed
1723          * that can be
1724          */
1725         sleep = mddev->bitmap_info.daemon_sleep * 2;
1726         bitmap->daemon_lastrun -= sleep;
1727         md_bitmap_daemon_work(mddev);
1728         bitmap->daemon_lastrun -= sleep;
1729         md_bitmap_daemon_work(mddev);
1730         bitmap->daemon_lastrun -= sleep;
1731         md_bitmap_daemon_work(mddev);
1732         md_bitmap_update_sb(bitmap);
1733 }
1734
1735 /*
1736  * free memory that was allocated
1737  */
1738 void md_bitmap_free(struct bitmap *bitmap)
1739 {
1740         unsigned long k, pages;
1741         struct bitmap_page *bp;
1742
1743         if (!bitmap) /* there was no bitmap */
1744                 return;
1745
1746         if (bitmap->sysfs_can_clear)
1747                 sysfs_put(bitmap->sysfs_can_clear);
1748
1749         if (mddev_is_clustered(bitmap->mddev) && bitmap->mddev->cluster_info &&
1750                 bitmap->cluster_slot == md_cluster_ops->slot_number(bitmap->mddev))
1751                 md_cluster_stop(bitmap->mddev);
1752
1753         /* Shouldn't be needed - but just in case.... */
1754         wait_event(bitmap->write_wait,
1755                    atomic_read(&bitmap->pending_writes) == 0);
1756
1757         /* release the bitmap file  */
1758         md_bitmap_file_unmap(&bitmap->storage);
1759
1760         bp = bitmap->counts.bp;
1761         pages = bitmap->counts.pages;
1762
1763         /* free all allocated memory */
1764
1765         if (bp) /* deallocate the page memory */
1766                 for (k = 0; k < pages; k++)
1767                         if (bp[k].map && !bp[k].hijacked)
1768                                 kfree(bp[k].map);
1769         kfree(bp);
1770         kfree(bitmap);
1771 }
1772 EXPORT_SYMBOL(md_bitmap_free);
1773
1774 void md_bitmap_wait_behind_writes(struct mddev *mddev)
1775 {
1776         struct bitmap *bitmap = mddev->bitmap;
1777
1778         /* wait for behind writes to complete */
1779         if (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
1780                 pr_debug("md:%s: behind writes in progress - waiting to stop.\n",
1781                          mdname(mddev));
1782                 /* need to kick something here to make sure I/O goes? */
1783                 wait_event(bitmap->behind_wait,
1784                            atomic_read(&bitmap->behind_writes) == 0);
1785         }
1786 }
1787
1788 void md_bitmap_destroy(struct mddev *mddev)
1789 {
1790         struct bitmap *bitmap = mddev->bitmap;
1791
1792         if (!bitmap) /* there was no bitmap */
1793                 return;
1794
1795         md_bitmap_wait_behind_writes(mddev);
1796         if (!mddev->serialize_policy)
1797                 mddev_destroy_serial_pool(mddev, NULL, true);
1798
1799         mutex_lock(&mddev->bitmap_info.mutex);
1800         spin_lock(&mddev->lock);
1801         mddev->bitmap = NULL; /* disconnect from the md device */
1802         spin_unlock(&mddev->lock);
1803         mutex_unlock(&mddev->bitmap_info.mutex);
1804         if (mddev->thread)
1805                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1806
1807         md_bitmap_free(bitmap);
1808 }
1809
1810 /*
1811  * initialize the bitmap structure
1812  * if this returns an error, bitmap_destroy must be called to do clean up
1813  * once mddev->bitmap is set
1814  */
1815 struct bitmap *md_bitmap_create(struct mddev *mddev, int slot)
1816 {
1817         struct bitmap *bitmap;
1818         sector_t blocks = mddev->resync_max_sectors;
1819         struct file *file = mddev->bitmap_info.file;
1820         int err;
1821         struct kernfs_node *bm = NULL;
1822
1823         BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
1824
1825         BUG_ON(file && mddev->bitmap_info.offset);
1826
1827         if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
1828                 pr_notice("md/raid:%s: array with journal cannot have bitmap\n",
1829                           mdname(mddev));
1830                 return ERR_PTR(-EBUSY);
1831         }
1832
1833         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1834         if (!bitmap)
1835                 return ERR_PTR(-ENOMEM);
1836
1837         spin_lock_init(&bitmap->counts.lock);
1838         atomic_set(&bitmap->pending_writes, 0);
1839         init_waitqueue_head(&bitmap->write_wait);
1840         init_waitqueue_head(&bitmap->overflow_wait);
1841         init_waitqueue_head(&bitmap->behind_wait);
1842
1843         bitmap->mddev = mddev;
1844         bitmap->cluster_slot = slot;
1845
1846         if (mddev->kobj.sd)
1847                 bm = sysfs_get_dirent(mddev->kobj.sd, "bitmap");
1848         if (bm) {
1849                 bitmap->sysfs_can_clear = sysfs_get_dirent(bm, "can_clear");
1850                 sysfs_put(bm);
1851         } else
1852                 bitmap->sysfs_can_clear = NULL;
1853
1854         bitmap->storage.file = file;
1855         if (file) {
1856                 get_file(file);
1857                 /* As future accesses to this file will use bmap,
1858                  * and bypass the page cache, we must sync the file
1859                  * first.
1860                  */
1861                 vfs_fsync(file, 1);
1862         }
1863         /* read superblock from bitmap file (this sets mddev->bitmap_info.chunksize) */
1864         if (!mddev->bitmap_info.external) {
1865                 /*
1866                  * If 'MD_ARRAY_FIRST_USE' is set, then device-mapper is
1867                  * instructing us to create a new on-disk bitmap instance.
1868                  */
1869                 if (test_and_clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags))
1870                         err = md_bitmap_new_disk_sb(bitmap);
1871                 else
1872                         err = md_bitmap_read_sb(bitmap);
1873         } else {
1874                 err = 0;
1875                 if (mddev->bitmap_info.chunksize == 0 ||
1876                     mddev->bitmap_info.daemon_sleep == 0)
1877                         /* chunksize and time_base need to be
1878                          * set first. */
1879                         err = -EINVAL;
1880         }
1881         if (err)
1882                 goto error;
1883
1884         bitmap->daemon_lastrun = jiffies;
1885         err = md_bitmap_resize(bitmap, blocks, mddev->bitmap_info.chunksize, 1);
1886         if (err)
1887                 goto error;
1888
1889         pr_debug("created bitmap (%lu pages) for device %s\n",
1890                  bitmap->counts.pages, bmname(bitmap));
1891
1892         err = test_bit(BITMAP_WRITE_ERROR, &bitmap->flags) ? -EIO : 0;
1893         if (err)
1894                 goto error;
1895
1896         return bitmap;
1897  error:
1898         md_bitmap_free(bitmap);
1899         return ERR_PTR(err);
1900 }
1901
1902 int md_bitmap_load(struct mddev *mddev)
1903 {
1904         int err = 0;
1905         sector_t start = 0;
1906         sector_t sector = 0;
1907         struct bitmap *bitmap = mddev->bitmap;
1908         struct md_rdev *rdev;
1909
1910         if (!bitmap)
1911                 goto out;
1912
1913         rdev_for_each(rdev, mddev)
1914                 mddev_create_serial_pool(mddev, rdev, true);
1915
1916         if (mddev_is_clustered(mddev))
1917                 md_cluster_ops->load_bitmaps(mddev, mddev->bitmap_info.nodes);
1918
1919         /* Clear out old bitmap info first:  Either there is none, or we
1920          * are resuming after someone else has possibly changed things,
1921          * so we should forget old cached info.
1922          * All chunks should be clean, but some might need_sync.
1923          */
1924         while (sector < mddev->resync_max_sectors) {
1925                 sector_t blocks;
1926                 md_bitmap_start_sync(bitmap, sector, &blocks, 0);
1927                 sector += blocks;
1928         }
1929         md_bitmap_close_sync(bitmap);
1930
1931         if (mddev->degraded == 0
1932             || bitmap->events_cleared == mddev->events)
1933                 /* no need to keep dirty bits to optimise a
1934                  * re-add of a missing device */
1935                 start = mddev->recovery_cp;
1936
1937         mutex_lock(&mddev->bitmap_info.mutex);
1938         err = md_bitmap_init_from_disk(bitmap, start);
1939         mutex_unlock(&mddev->bitmap_info.mutex);
1940
1941         if (err)
1942                 goto out;
1943         clear_bit(BITMAP_STALE, &bitmap->flags);
1944
1945         /* Kick recovery in case any bits were set */
1946         set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
1947
1948         mddev->thread->timeout = mddev->bitmap_info.daemon_sleep;
1949         md_wakeup_thread(mddev->thread);
1950
1951         md_bitmap_update_sb(bitmap);
1952
1953         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
1954                 err = -EIO;
1955 out:
1956         return err;
1957 }
1958 EXPORT_SYMBOL_GPL(md_bitmap_load);
1959
1960 struct bitmap *get_bitmap_from_slot(struct mddev *mddev, int slot)
1961 {
1962         int rv = 0;
1963         struct bitmap *bitmap;
1964
1965         bitmap = md_bitmap_create(mddev, slot);
1966         if (IS_ERR(bitmap)) {
1967                 rv = PTR_ERR(bitmap);
1968                 return ERR_PTR(rv);
1969         }
1970
1971         rv = md_bitmap_init_from_disk(bitmap, 0);
1972         if (rv) {
1973                 md_bitmap_free(bitmap);
1974                 return ERR_PTR(rv);
1975         }
1976
1977         return bitmap;
1978 }
1979 EXPORT_SYMBOL(get_bitmap_from_slot);
1980
1981 /* Loads the bitmap associated with slot and copies the resync information
1982  * to our bitmap
1983  */
1984 int md_bitmap_copy_from_slot(struct mddev *mddev, int slot,
1985                 sector_t *low, sector_t *high, bool clear_bits)
1986 {
1987         int rv = 0, i, j;
1988         sector_t block, lo = 0, hi = 0;
1989         struct bitmap_counts *counts;
1990         struct bitmap *bitmap;
1991
1992         bitmap = get_bitmap_from_slot(mddev, slot);
1993         if (IS_ERR(bitmap)) {
1994                 pr_err("%s can't get bitmap from slot %d\n", __func__, slot);
1995                 return -1;
1996         }
1997
1998         counts = &bitmap->counts;
1999         for (j = 0; j < counts->chunks; j++) {
2000                 block = (sector_t)j << counts->chunkshift;
2001                 if (md_bitmap_file_test_bit(bitmap, block)) {
2002                         if (!lo)
2003                                 lo = block;
2004                         hi = block;
2005                         md_bitmap_file_clear_bit(bitmap, block);
2006                         md_bitmap_set_memory_bits(mddev->bitmap, block, 1);
2007                         md_bitmap_file_set_bit(mddev->bitmap, block);
2008                 }
2009         }
2010
2011         if (clear_bits) {
2012                 md_bitmap_update_sb(bitmap);
2013                 /* BITMAP_PAGE_PENDING is set, but bitmap_unplug needs
2014                  * BITMAP_PAGE_DIRTY or _NEEDWRITE to write ... */
2015                 for (i = 0; i < bitmap->storage.file_pages; i++)
2016                         if (test_page_attr(bitmap, i, BITMAP_PAGE_PENDING))
2017                                 set_page_attr(bitmap, i, BITMAP_PAGE_NEEDWRITE);
2018                 md_bitmap_unplug(bitmap);
2019         }
2020         md_bitmap_unplug(mddev->bitmap);
2021         *low = lo;
2022         *high = hi;
2023
2024         return rv;
2025 }
2026 EXPORT_SYMBOL_GPL(md_bitmap_copy_from_slot);
2027
2028
2029 void md_bitmap_status(struct seq_file *seq, struct bitmap *bitmap)
2030 {
2031         unsigned long chunk_kb;
2032         struct bitmap_counts *counts;
2033
2034         if (!bitmap)
2035                 return;
2036
2037         counts = &bitmap->counts;
2038
2039         chunk_kb = bitmap->mddev->bitmap_info.chunksize >> 10;
2040         seq_printf(seq, "bitmap: %lu/%lu pages [%luKB], "
2041                    "%lu%s chunk",
2042                    counts->pages - counts->missing_pages,
2043                    counts->pages,
2044                    (counts->pages - counts->missing_pages)
2045                    << (PAGE_SHIFT - 10),
2046                    chunk_kb ? chunk_kb : bitmap->mddev->bitmap_info.chunksize,
2047                    chunk_kb ? "KB" : "B");
2048         if (bitmap->storage.file) {
2049                 seq_printf(seq, ", file: ");
2050                 seq_file_path(seq, bitmap->storage.file, " \t\n");
2051         }
2052
2053         seq_printf(seq, "\n");
2054 }
2055
2056 int md_bitmap_resize(struct bitmap *bitmap, sector_t blocks,
2057                   int chunksize, int init)
2058 {
2059         /* If chunk_size is 0, choose an appropriate chunk size.
2060          * Then possibly allocate new storage space.
2061          * Then quiesce, copy bits, replace bitmap, and re-start
2062          *
2063          * This function is called both to set up the initial bitmap
2064          * and to resize the bitmap while the array is active.
2065          * If this happens as a result of the array being resized,
2066          * chunksize will be zero, and we need to choose a suitable
2067          * chunksize, otherwise we use what we are given.
2068          */
2069         struct bitmap_storage store;
2070         struct bitmap_counts old_counts;
2071         unsigned long chunks;
2072         sector_t block;
2073         sector_t old_blocks, new_blocks;
2074         int chunkshift;
2075         int ret = 0;
2076         long pages;
2077         struct bitmap_page *new_bp;
2078
2079         if (bitmap->storage.file && !init) {
2080                 pr_info("md: cannot resize file-based bitmap\n");
2081                 return -EINVAL;
2082         }
2083
2084         if (chunksize == 0) {
2085                 /* If there is enough space, leave the chunk size unchanged,
2086                  * else increase by factor of two until there is enough space.
2087                  */
2088                 long bytes;
2089                 long space = bitmap->mddev->bitmap_info.space;
2090
2091                 if (space == 0) {
2092                         /* We don't know how much space there is, so limit
2093                          * to current size - in sectors.
2094                          */
2095                         bytes = DIV_ROUND_UP(bitmap->counts.chunks, 8);
2096                         if (!bitmap->mddev->bitmap_info.external)
2097                                 bytes += sizeof(bitmap_super_t);
2098                         space = DIV_ROUND_UP(bytes, 512);
2099                         bitmap->mddev->bitmap_info.space = space;
2100                 }
2101                 chunkshift = bitmap->counts.chunkshift;
2102                 chunkshift--;
2103                 do {
2104                         /* 'chunkshift' is shift from block size to chunk size */
2105                         chunkshift++;
2106                         chunks = DIV_ROUND_UP_SECTOR_T(blocks, 1 << chunkshift);
2107                         bytes = DIV_ROUND_UP(chunks, 8);
2108                         if (!bitmap->mddev->bitmap_info.external)
2109                                 bytes += sizeof(bitmap_super_t);
2110                 } while (bytes > (space << 9));
2111         } else
2112                 chunkshift = ffz(~chunksize) - BITMAP_BLOCK_SHIFT;
2113
2114         chunks = DIV_ROUND_UP_SECTOR_T(blocks, 1 << chunkshift);
2115         memset(&store, 0, sizeof(store));
2116         if (bitmap->mddev->bitmap_info.offset || bitmap->mddev->bitmap_info.file)
2117                 ret = md_bitmap_storage_alloc(&store, chunks,
2118                                               !bitmap->mddev->bitmap_info.external,
2119                                               mddev_is_clustered(bitmap->mddev)
2120                                               ? bitmap->cluster_slot : 0);
2121         if (ret) {
2122                 md_bitmap_file_unmap(&store);
2123                 goto err;
2124         }
2125
2126         pages = DIV_ROUND_UP(chunks, PAGE_COUNTER_RATIO);
2127
2128         new_bp = kcalloc(pages, sizeof(*new_bp), GFP_KERNEL);
2129         ret = -ENOMEM;
2130         if (!new_bp) {
2131                 md_bitmap_file_unmap(&store);
2132                 goto err;
2133         }
2134
2135         if (!init)
2136                 bitmap->mddev->pers->quiesce(bitmap->mddev, 1);
2137
2138         store.file = bitmap->storage.file;
2139         bitmap->storage.file = NULL;
2140
2141         if (store.sb_page && bitmap->storage.sb_page)
2142                 memcpy(page_address(store.sb_page),
2143                        page_address(bitmap->storage.sb_page),
2144                        sizeof(bitmap_super_t));
2145         spin_lock_irq(&bitmap->counts.lock);
2146         md_bitmap_file_unmap(&bitmap->storage);
2147         bitmap->storage = store;
2148
2149         old_counts = bitmap->counts;
2150         bitmap->counts.bp = new_bp;
2151         bitmap->counts.pages = pages;
2152         bitmap->counts.missing_pages = pages;
2153         bitmap->counts.chunkshift = chunkshift;
2154         bitmap->counts.chunks = chunks;
2155         bitmap->mddev->bitmap_info.chunksize = 1 << (chunkshift +
2156                                                      BITMAP_BLOCK_SHIFT);
2157
2158         blocks = min(old_counts.chunks << old_counts.chunkshift,
2159                      chunks << chunkshift);
2160
2161         /* For cluster raid, need to pre-allocate bitmap */
2162         if (mddev_is_clustered(bitmap->mddev)) {
2163                 unsigned long page;
2164                 for (page = 0; page < pages; page++) {
2165                         ret = md_bitmap_checkpage(&bitmap->counts, page, 1, 1);
2166                         if (ret) {
2167                                 unsigned long k;
2168
2169                                 /* deallocate the page memory */
2170                                 for (k = 0; k < page; k++) {
2171                                         kfree(new_bp[k].map);
2172                                 }
2173                                 kfree(new_bp);
2174
2175                                 /* restore some fields from old_counts */
2176                                 bitmap->counts.bp = old_counts.bp;
2177                                 bitmap->counts.pages = old_counts.pages;
2178                                 bitmap->counts.missing_pages = old_counts.pages;
2179                                 bitmap->counts.chunkshift = old_counts.chunkshift;
2180                                 bitmap->counts.chunks = old_counts.chunks;
2181                                 bitmap->mddev->bitmap_info.chunksize = 1 << (old_counts.chunkshift +
2182                                                                              BITMAP_BLOCK_SHIFT);
2183                                 blocks = old_counts.chunks << old_counts.chunkshift;
2184                                 pr_warn("Could not pre-allocate in-memory bitmap for cluster raid\n");
2185                                 break;
2186                         } else
2187                                 bitmap->counts.bp[page].count += 1;
2188                 }
2189         }
2190
2191         for (block = 0; block < blocks; ) {
2192                 bitmap_counter_t *bmc_old, *bmc_new;
2193                 int set;
2194
2195                 bmc_old = md_bitmap_get_counter(&old_counts, block, &old_blocks, 0);
2196                 set = bmc_old && NEEDED(*bmc_old);
2197
2198                 if (set) {
2199                         bmc_new = md_bitmap_get_counter(&bitmap->counts, block, &new_blocks, 1);
2200                         if (*bmc_new == 0) {
2201                                 /* need to set on-disk bits too. */
2202                                 sector_t end = block + new_blocks;
2203                                 sector_t start = block >> chunkshift;
2204                                 start <<= chunkshift;
2205                                 while (start < end) {
2206                                         md_bitmap_file_set_bit(bitmap, block);
2207                                         start += 1 << chunkshift;
2208                                 }
2209                                 *bmc_new = 2;
2210                                 md_bitmap_count_page(&bitmap->counts, block, 1);
2211                                 md_bitmap_set_pending(&bitmap->counts, block);
2212                         }
2213                         *bmc_new |= NEEDED_MASK;
2214                         if (new_blocks < old_blocks)
2215                                 old_blocks = new_blocks;
2216                 }
2217                 block += old_blocks;
2218         }
2219
2220         if (bitmap->counts.bp != old_counts.bp) {
2221                 unsigned long k;
2222                 for (k = 0; k < old_counts.pages; k++)
2223                         if (!old_counts.bp[k].hijacked)
2224                                 kfree(old_counts.bp[k].map);
2225                 kfree(old_counts.bp);
2226         }
2227
2228         if (!init) {
2229                 int i;
2230                 while (block < (chunks << chunkshift)) {
2231                         bitmap_counter_t *bmc;
2232                         bmc = md_bitmap_get_counter(&bitmap->counts, block, &new_blocks, 1);
2233                         if (bmc) {
2234                                 /* new space.  It needs to be resynced, so
2235                                  * we set NEEDED_MASK.
2236                                  */
2237                                 if (*bmc == 0) {
2238                                         *bmc = NEEDED_MASK | 2;
2239                                         md_bitmap_count_page(&bitmap->counts, block, 1);
2240                                         md_bitmap_set_pending(&bitmap->counts, block);
2241                                 }
2242                         }
2243                         block += new_blocks;
2244                 }
2245                 for (i = 0; i < bitmap->storage.file_pages; i++)
2246                         set_page_attr(bitmap, i, BITMAP_PAGE_DIRTY);
2247         }
2248         spin_unlock_irq(&bitmap->counts.lock);
2249
2250         if (!init) {
2251                 md_bitmap_unplug(bitmap);
2252                 bitmap->mddev->pers->quiesce(bitmap->mddev, 0);
2253         }
2254         ret = 0;
2255 err:
2256         return ret;
2257 }
2258 EXPORT_SYMBOL_GPL(md_bitmap_resize);
2259
2260 static ssize_t
2261 location_show(struct mddev *mddev, char *page)
2262 {
2263         ssize_t len;
2264         if (mddev->bitmap_info.file)
2265                 len = sprintf(page, "file");
2266         else if (mddev->bitmap_info.offset)
2267                 len = sprintf(page, "%+lld", (long long)mddev->bitmap_info.offset);
2268         else
2269                 len = sprintf(page, "none");
2270         len += sprintf(page+len, "\n");
2271         return len;
2272 }
2273
2274 static ssize_t
2275 location_store(struct mddev *mddev, const char *buf, size_t len)
2276 {
2277         int rv;
2278
2279         rv = mddev_lock(mddev);
2280         if (rv)
2281                 return rv;
2282         if (mddev->pers) {
2283                 if (!mddev->pers->quiesce) {
2284                         rv = -EBUSY;
2285                         goto out;
2286                 }
2287                 if (mddev->recovery || mddev->sync_thread) {
2288                         rv = -EBUSY;
2289                         goto out;
2290                 }
2291         }
2292
2293         if (mddev->bitmap || mddev->bitmap_info.file ||
2294             mddev->bitmap_info.offset) {
2295                 /* bitmap already configured.  Only option is to clear it */
2296                 if (strncmp(buf, "none", 4) != 0) {
2297                         rv = -EBUSY;
2298                         goto out;
2299                 }
2300                 if (mddev->pers) {
2301                         mddev_suspend(mddev);
2302                         md_bitmap_destroy(mddev);
2303                         mddev_resume(mddev);
2304                 }
2305                 mddev->bitmap_info.offset = 0;
2306                 if (mddev->bitmap_info.file) {
2307                         struct file *f = mddev->bitmap_info.file;
2308                         mddev->bitmap_info.file = NULL;
2309                         fput(f);
2310                 }
2311         } else {
2312                 /* No bitmap, OK to set a location */
2313                 long long offset;
2314                 if (strncmp(buf, "none", 4) == 0)
2315                         /* nothing to be done */;
2316                 else if (strncmp(buf, "file:", 5) == 0) {
2317                         /* Not supported yet */
2318                         rv = -EINVAL;
2319                         goto out;
2320                 } else {
2321                         if (buf[0] == '+')
2322                                 rv = kstrtoll(buf+1, 10, &offset);
2323                         else
2324                                 rv = kstrtoll(buf, 10, &offset);
2325                         if (rv)
2326                                 goto out;
2327                         if (offset == 0) {
2328                                 rv = -EINVAL;
2329                                 goto out;
2330                         }
2331                         if (mddev->bitmap_info.external == 0 &&
2332                             mddev->major_version == 0 &&
2333                             offset != mddev->bitmap_info.default_offset) {
2334                                 rv = -EINVAL;
2335                                 goto out;
2336                         }
2337                         mddev->bitmap_info.offset = offset;
2338                         if (mddev->pers) {
2339                                 struct bitmap *bitmap;
2340                                 bitmap = md_bitmap_create(mddev, -1);
2341                                 mddev_suspend(mddev);
2342                                 if (IS_ERR(bitmap))
2343                                         rv = PTR_ERR(bitmap);
2344                                 else {
2345                                         mddev->bitmap = bitmap;
2346                                         rv = md_bitmap_load(mddev);
2347                                         if (rv)
2348                                                 mddev->bitmap_info.offset = 0;
2349                                 }
2350                                 if (rv) {
2351                                         md_bitmap_destroy(mddev);
2352                                         mddev_resume(mddev);
2353                                         goto out;
2354                                 }
2355                                 mddev_resume(mddev);
2356                         }
2357                 }
2358         }
2359         if (!mddev->external) {
2360                 /* Ensure new bitmap info is stored in
2361                  * metadata promptly.
2362                  */
2363                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
2364                 md_wakeup_thread(mddev->thread);
2365         }
2366         rv = 0;
2367 out:
2368         mddev_unlock(mddev);
2369         if (rv)
2370                 return rv;
2371         return len;
2372 }
2373
2374 static struct md_sysfs_entry bitmap_location =
2375 __ATTR(location, S_IRUGO|S_IWUSR, location_show, location_store);
2376
2377 /* 'bitmap/space' is the space available at 'location' for the
2378  * bitmap.  This allows the kernel to know when it is safe to
2379  * resize the bitmap to match a resized array.
2380  */
2381 static ssize_t
2382 space_show(struct mddev *mddev, char *page)
2383 {
2384         return sprintf(page, "%lu\n", mddev->bitmap_info.space);
2385 }
2386
2387 static ssize_t
2388 space_store(struct mddev *mddev, const char *buf, size_t len)
2389 {
2390         unsigned long sectors;
2391         int rv;
2392
2393         rv = kstrtoul(buf, 10, &sectors);
2394         if (rv)
2395                 return rv;
2396
2397         if (sectors == 0)
2398                 return -EINVAL;
2399
2400         if (mddev->bitmap &&
2401             sectors < (mddev->bitmap->storage.bytes + 511) >> 9)
2402                 return -EFBIG; /* Bitmap is too big for this small space */
2403
2404         /* could make sure it isn't too big, but that isn't really
2405          * needed - user-space should be careful.
2406          */
2407         mddev->bitmap_info.space = sectors;
2408         return len;
2409 }
2410
2411 static struct md_sysfs_entry bitmap_space =
2412 __ATTR(space, S_IRUGO|S_IWUSR, space_show, space_store);
2413
2414 static ssize_t
2415 timeout_show(struct mddev *mddev, char *page)
2416 {
2417         ssize_t len;
2418         unsigned long secs = mddev->bitmap_info.daemon_sleep / HZ;
2419         unsigned long jifs = mddev->bitmap_info.daemon_sleep % HZ;
2420
2421         len = sprintf(page, "%lu", secs);
2422         if (jifs)
2423                 len += sprintf(page+len, ".%03u", jiffies_to_msecs(jifs));
2424         len += sprintf(page+len, "\n");
2425         return len;
2426 }
2427
2428 static ssize_t
2429 timeout_store(struct mddev *mddev, const char *buf, size_t len)
2430 {
2431         /* timeout can be set at any time */
2432         unsigned long timeout;
2433         int rv = strict_strtoul_scaled(buf, &timeout, 4);
2434         if (rv)
2435                 return rv;
2436
2437         /* just to make sure we don't overflow... */
2438         if (timeout >= LONG_MAX / HZ)
2439                 return -EINVAL;
2440
2441         timeout = timeout * HZ / 10000;
2442
2443         if (timeout >= MAX_SCHEDULE_TIMEOUT)
2444                 timeout = MAX_SCHEDULE_TIMEOUT-1;
2445         if (timeout < 1)
2446                 timeout = 1;
2447         mddev->bitmap_info.daemon_sleep = timeout;
2448         if (mddev->thread) {
2449                 /* if thread->timeout is MAX_SCHEDULE_TIMEOUT, then
2450                  * the bitmap is all clean and we don't need to
2451                  * adjust the timeout right now
2452                  */
2453                 if (mddev->thread->timeout < MAX_SCHEDULE_TIMEOUT) {
2454                         mddev->thread->timeout = timeout;
2455                         md_wakeup_thread(mddev->thread);
2456                 }
2457         }
2458         return len;
2459 }
2460
2461 static struct md_sysfs_entry bitmap_timeout =
2462 __ATTR(time_base, S_IRUGO|S_IWUSR, timeout_show, timeout_store);
2463
2464 static ssize_t
2465 backlog_show(struct mddev *mddev, char *page)
2466 {
2467         return sprintf(page, "%lu\n", mddev->bitmap_info.max_write_behind);
2468 }
2469
2470 static ssize_t
2471 backlog_store(struct mddev *mddev, const char *buf, size_t len)
2472 {
2473         unsigned long backlog;
2474         unsigned long old_mwb = mddev->bitmap_info.max_write_behind;
2475         int rv = kstrtoul(buf, 10, &backlog);
2476         if (rv)
2477                 return rv;
2478         if (backlog > COUNTER_MAX)
2479                 return -EINVAL;
2480         mddev->bitmap_info.max_write_behind = backlog;
2481         if (!backlog && mddev->serial_info_pool) {
2482                 /* serial_info_pool is not needed if backlog is zero */
2483                 if (!mddev->serialize_policy)
2484                         mddev_destroy_serial_pool(mddev, NULL, false);
2485         } else if (backlog && !mddev->serial_info_pool) {
2486                 /* serial_info_pool is needed since backlog is not zero */
2487                 struct md_rdev *rdev;
2488
2489                 rdev_for_each(rdev, mddev)
2490                         mddev_create_serial_pool(mddev, rdev, false);
2491         }
2492         if (old_mwb != backlog)
2493                 md_bitmap_update_sb(mddev->bitmap);
2494         return len;
2495 }
2496
2497 static struct md_sysfs_entry bitmap_backlog =
2498 __ATTR(backlog, S_IRUGO|S_IWUSR, backlog_show, backlog_store);
2499
2500 static ssize_t
2501 chunksize_show(struct mddev *mddev, char *page)
2502 {
2503         return sprintf(page, "%lu\n", mddev->bitmap_info.chunksize);
2504 }
2505
2506 static ssize_t
2507 chunksize_store(struct mddev *mddev, const char *buf, size_t len)
2508 {
2509         /* Can only be changed when no bitmap is active */
2510         int rv;
2511         unsigned long csize;
2512         if (mddev->bitmap)
2513                 return -EBUSY;
2514         rv = kstrtoul(buf, 10, &csize);
2515         if (rv)
2516                 return rv;
2517         if (csize < 512 ||
2518             !is_power_of_2(csize))
2519                 return -EINVAL;
2520         mddev->bitmap_info.chunksize = csize;
2521         return len;
2522 }
2523
2524 static struct md_sysfs_entry bitmap_chunksize =
2525 __ATTR(chunksize, S_IRUGO|S_IWUSR, chunksize_show, chunksize_store);
2526
2527 static ssize_t metadata_show(struct mddev *mddev, char *page)
2528 {
2529         if (mddev_is_clustered(mddev))
2530                 return sprintf(page, "clustered\n");
2531         return sprintf(page, "%s\n", (mddev->bitmap_info.external
2532                                       ? "external" : "internal"));
2533 }
2534
2535 static ssize_t metadata_store(struct mddev *mddev, const char *buf, size_t len)
2536 {
2537         if (mddev->bitmap ||
2538             mddev->bitmap_info.file ||
2539             mddev->bitmap_info.offset)
2540                 return -EBUSY;
2541         if (strncmp(buf, "external", 8) == 0)
2542                 mddev->bitmap_info.external = 1;
2543         else if ((strncmp(buf, "internal", 8) == 0) ||
2544                         (strncmp(buf, "clustered", 9) == 0))
2545                 mddev->bitmap_info.external = 0;
2546         else
2547                 return -EINVAL;
2548         return len;
2549 }
2550
2551 static struct md_sysfs_entry bitmap_metadata =
2552 __ATTR(metadata, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
2553
2554 static ssize_t can_clear_show(struct mddev *mddev, char *page)
2555 {
2556         int len;
2557         spin_lock(&mddev->lock);
2558         if (mddev->bitmap)
2559                 len = sprintf(page, "%s\n", (mddev->bitmap->need_sync ?
2560                                              "false" : "true"));
2561         else
2562                 len = sprintf(page, "\n");
2563         spin_unlock(&mddev->lock);
2564         return len;
2565 }
2566
2567 static ssize_t can_clear_store(struct mddev *mddev, const char *buf, size_t len)
2568 {
2569         if (mddev->bitmap == NULL)
2570                 return -ENOENT;
2571         if (strncmp(buf, "false", 5) == 0)
2572                 mddev->bitmap->need_sync = 1;
2573         else if (strncmp(buf, "true", 4) == 0) {
2574                 if (mddev->degraded)
2575                         return -EBUSY;
2576                 mddev->bitmap->need_sync = 0;
2577         } else
2578                 return -EINVAL;
2579         return len;
2580 }
2581
2582 static struct md_sysfs_entry bitmap_can_clear =
2583 __ATTR(can_clear, S_IRUGO|S_IWUSR, can_clear_show, can_clear_store);
2584
2585 static ssize_t
2586 behind_writes_used_show(struct mddev *mddev, char *page)
2587 {
2588         ssize_t ret;
2589         spin_lock(&mddev->lock);
2590         if (mddev->bitmap == NULL)
2591                 ret = sprintf(page, "0\n");
2592         else
2593                 ret = sprintf(page, "%lu\n",
2594                               mddev->bitmap->behind_writes_used);
2595         spin_unlock(&mddev->lock);
2596         return ret;
2597 }
2598
2599 static ssize_t
2600 behind_writes_used_reset(struct mddev *mddev, const char *buf, size_t len)
2601 {
2602         if (mddev->bitmap)
2603                 mddev->bitmap->behind_writes_used = 0;
2604         return len;
2605 }
2606
2607 static struct md_sysfs_entry max_backlog_used =
2608 __ATTR(max_backlog_used, S_IRUGO | S_IWUSR,
2609        behind_writes_used_show, behind_writes_used_reset);
2610
2611 static struct attribute *md_bitmap_attrs[] = {
2612         &bitmap_location.attr,
2613         &bitmap_space.attr,
2614         &bitmap_timeout.attr,
2615         &bitmap_backlog.attr,
2616         &bitmap_chunksize.attr,
2617         &bitmap_metadata.attr,
2618         &bitmap_can_clear.attr,
2619         &max_backlog_used.attr,
2620         NULL
2621 };
2622 struct attribute_group md_bitmap_group = {
2623         .name = "bitmap",
2624         .attrs = md_bitmap_attrs,
2625 };
2626