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, true)) {
 169                         page->index = index;
 170                         return 0;
 171                 }
 172         }
 173         return -EIO;
 174 }
 175
 176 static struct md_rdev *next_active_rdev(struct md_rdev *rdev, struct mddev *mddev)
 177 {
 178         /* Iterate the disks of an mddev, using rcu to protect access to the
 179          * linked list, and raising the refcount of devices we return to ensure
 180          * they don't disappear while in use.
 181          * As devices are only added or removed when raid_disk is < 0 and
 182          * nr_pending is 0 and In_sync is clear, the entries we return will
 183          * still be in the same position on the list when we re-enter
 184          * list_for_each_entry_continue_rcu.
 185          *
 186          * Note that if entered with 'rdev == NULL' to start at the
 187          * beginning, we temporarily assign 'rdev' to an address which
 188          * isn't really an rdev, but which can be used by
 189          * list_for_each_entry_continue_rcu() to find the first entry.
 190          */
 191         rcu_read_lock();
 192         if (rdev == NULL)
 193                 /* start at the beginning */
 194                 rdev = list_entry(&mddev->disks, struct md_rdev, same_set);
 195         else {
 196                 /* release the previous rdev and start from there. */
 197                 rdev_dec_pending(rdev, mddev);
 198         }
 199         list_for_each_entry_continue_rcu(rdev, &mddev->disks, same_set) {
 200                 if (rdev->raid_disk >= 0 &&
 201                     !test_bit(Faulty, &rdev->flags)) {
 202                         /* this is a usable devices */
 203                         atomic_inc(&rdev->nr_pending);
 204                         rcu_read_unlock();
 205                         return rdev;
 206                 }
 207         }
 208         rcu_read_unlock();
 209         return NULL;
 210 }
 211
 212 static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
 213 {
 214         struct md_rdev *rdev;
 215         struct block_device *bdev;
 216         struct mddev *mddev = bitmap->mddev;
 217         struct bitmap_storage *store = &bitmap->storage;
 218
 219 restart:
 220         rdev = NULL;
 221         while ((rdev = next_active_rdev(rdev, mddev)) != NULL) {
 222                 int size = PAGE_SIZE;
 223                 loff_t offset = mddev->bitmap_info.offset;
 224
 225                 bdev = (rdev->meta_bdev) ? rdev->meta_bdev : rdev->bdev;
 226
 227                 if (page->index == store->file_pages-1) {
 228                         int last_page_size = store->bytes & (PAGE_SIZE-1);
 229                         if (last_page_size == 0)
 230                                 last_page_size = PAGE_SIZE;
 231                         size = roundup(last_page_size,
 232                                        bdev_logical_block_size(bdev));
 233                 }
 234                 /* Just make sure we aren't corrupting data or
 235                  * metadata
 236                  */
 237                 if (mddev->external) {
 238                         /* Bitmap could be anywhere. */
 239                         if (rdev->sb_start + offset + (page->index
 240                                                        * (PAGE_SIZE/512))
 241                             > rdev->data_offset
 242                             &&
 243                             rdev->sb_start + offset
 244                             < (rdev->data_offset + mddev->dev_sectors
 245                              + (PAGE_SIZE/512)))
 246                                 goto bad_alignment;
 247                 } else if (offset < 0) {
 248                         /* DATA  BITMAP METADATA  */
 249                         if (offset
 250                             + (long)(page->index * (PAGE_SIZE/512))
 251                             + size/512 > 0)
 252                                 /* bitmap runs in to metadata */
 253                                 goto bad_alignment;
 254                         if (rdev->data_offset + mddev->dev_sectors
 255                             > rdev->sb_start + offset)
 256                                 /* data runs in to bitmap */
 257                                 goto bad_alignment;
 258                 } else if (rdev->sb_start < rdev->data_offset) {
 259                         /* METADATA BITMAP DATA */
 260                         if (rdev->sb_start
 261                             + offset
 262                             + page->index*(PAGE_SIZE/512) + size/512
 263                             > rdev->data_offset)
 264                                 /* bitmap runs in to data */
 265                                 goto bad_alignment;
 266                 } else {
 267                         /* DATA METADATA BITMAP - no problems */
 268                 }
 269                 md_super_write(mddev, rdev,
 270                                rdev->sb_start + offset
 271                                + page->index * (PAGE_SIZE/512),
 272                                size,
 273                                page);
 274         }
 275
 276         if (wait && md_super_wait(mddev) < 0)
 277                 goto restart;
 278         return 0;
 279
 280  bad_alignment:
 281         return -EINVAL;
 282 }
 283
 284 static void md_bitmap_file_kick(struct bitmap *bitmap);
 285 /*
 286  * write out a page to a file
 287  */
 288 static void write_page(struct bitmap *bitmap, struct page *page, int wait)
 289 {
 290         struct buffer_head *bh;
 291
 292         if (bitmap->storage.file == NULL) {
 293                 switch (write_sb_page(bitmap, page, wait)) {
 294                 case -EINVAL:
 295                         set_bit(BITMAP_WRITE_ERROR, &bitmap->flags);
 296                 }
 297         } else {
 298
 299                 bh = page_buffers(page);
 300
 301                 while (bh && bh->b_blocknr) {
 302                         atomic_inc(&bitmap->pending_writes);
 303                         set_buffer_locked(bh);
 304                         set_buffer_mapped(bh);
 305                         submit_bh(REQ_OP_WRITE | REQ_SYNC, bh);
 306                         bh = bh->b_this_page;
 307                 }
 308
 309                 if (wait)
 310                         wait_event(bitmap->write_wait,
 311                                    atomic_read(&bitmap->pending_writes)==0);
 312         }
 313         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
 314                 md_bitmap_file_kick(bitmap);
 315 }
 316
 317 static void end_bitmap_write(struct buffer_head *bh, int uptodate)
 318 {
 319         struct bitmap *bitmap = bh->b_private;
 320
 321         if (!uptodate)
 322                 set_bit(BITMAP_WRITE_ERROR, &bitmap->flags);
 323         if (atomic_dec_and_test(&bitmap->pending_writes))
 324                 wake_up(&bitmap->write_wait);
 325 }
 326
 327 static void free_buffers(struct page *page)
 328 {
 329         struct buffer_head *bh;
 330
 331         if (!PagePrivate(page))
 332                 return;
 333
 334         bh = page_buffers(page);
 335         while (bh) {
 336                 struct buffer_head *next = bh->b_this_page;
 337                 free_buffer_head(bh);
 338                 bh = next;
 339         }
 340         detach_page_private(page);
 341         put_page(page);
 342 }
 343
 344 /* read a page from a file.
 345  * We both read the page, and attach buffers to the page to record the
 346  * address of each block (using bmap).  These addresses will be used
 347  * to write the block later, completely bypassing the filesystem.
 348  * This usage is similar to how swap files are handled, and allows us
 349  * to write to a file with no concerns of memory allocation failing.
 350  */
 351 static int read_page(struct file *file, unsigned long index,
 352                      struct bitmap *bitmap,
 353                      unsigned long count,
 354                      struct page *page)
 355 {
 356         int ret = 0;
 357         struct inode *inode = file_inode(file);
 358         struct buffer_head *bh;
 359         sector_t block, blk_cur;
 360         unsigned long blocksize = i_blocksize(inode);
 361
 362         pr_debug("read bitmap file (%dB @ %llu)\n", (int)PAGE_SIZE,
 363                  (unsigned long long)index << PAGE_SHIFT);
 364
 365         bh = alloc_page_buffers(page, blocksize, false);
 366         if (!bh) {
 367                 ret = -ENOMEM;
 368                 goto out;
 369         }
 370         attach_page_private(page, bh);
 371         blk_cur = index << (PAGE_SHIFT - inode->i_blkbits);
 372         while (bh) {
 373                 block = blk_cur;
 374
 375                 if (count == 0)
 376                         bh->b_blocknr = 0;
 377                 else {
 378                         ret = bmap(inode, &block);
 379                         if (ret || !block) {
 380                                 ret = -EINVAL;
 381                                 bh->b_blocknr = 0;
 382                                 goto out;
 383                         }
 384
 385                         bh->b_blocknr = block;
 386                         bh->b_bdev = inode->i_sb->s_bdev;
 387                         if (count < blocksize)
 388                                 count = 0;
 389                         else
 390                                 count -= blocksize;
 391
 392                         bh->b_end_io = end_bitmap_write;
 393                         bh->b_private = bitmap;
 394                         atomic_inc(&bitmap->pending_writes);
 395                         set_buffer_locked(bh);
 396                         set_buffer_mapped(bh);
 397                         submit_bh(REQ_OP_READ, bh);
 398                 }
 399                 blk_cur++;
 400                 bh = bh->b_this_page;
 401         }
 402         page->index = index;
 403
 404         wait_event(bitmap->write_wait,
 405                    atomic_read(&bitmap->pending_writes)==0);
 406         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
 407                 ret = -EIO;
 408 out:
 409         if (ret)
 410                 pr_err("md: bitmap read error: (%dB @ %llu): %d\n",
 411                        (int)PAGE_SIZE,
 412                        (unsigned long long)index << PAGE_SHIFT,
 413                        ret);
 414         return ret;
 415 }
 416
 417 /*
 418  * bitmap file superblock operations
 419  */
 420
 421 /*
 422  * md_bitmap_wait_writes() should be called before writing any bitmap
 423  * blocks, to ensure previous writes, particularly from
 424  * md_bitmap_daemon_work(), have completed.
 425  */
 426 static void md_bitmap_wait_writes(struct bitmap *bitmap)
 427 {
 428         if (bitmap->storage.file)
 429                 wait_event(bitmap->write_wait,
 430                            atomic_read(&bitmap->pending_writes)==0);
 431         else
 432                 /* Note that we ignore the return value.  The writes
 433                  * might have failed, but that would just mean that
 434                  * some bits which should be cleared haven't been,
 435                  * which is safe.  The relevant bitmap blocks will
 436                  * probably get written again, but there is no great
 437                  * loss if they aren't.
 438                  */
 439                 md_super_wait(bitmap->mddev);
 440 }
 441
 442
 443 /* update the event counter and sync the superblock to disk */
 444 void md_bitmap_update_sb(struct bitmap *bitmap)
 445 {
 446         bitmap_super_t *sb;
 447
 448         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
 449                 return;
 450         if (bitmap->mddev->bitmap_info.external)
 451                 return;
 452         if (!bitmap->storage.sb_page) /* no superblock */
 453                 return;
 454         sb = kmap_atomic(bitmap->storage.sb_page);
 455         sb->events = cpu_to_le64(bitmap->mddev->events);
 456         if (bitmap->mddev->events < bitmap->events_cleared)
 457                 /* rocking back to read-only */
 458                 bitmap->events_cleared = bitmap->mddev->events;
 459         sb->events_cleared = cpu_to_le64(bitmap->events_cleared);
 460         /*
 461          * clear BITMAP_WRITE_ERROR bit to protect against the case that
 462          * a bitmap write error occurred but the later writes succeeded.
 463          */
 464         sb->state = cpu_to_le32(bitmap->flags & ~BIT(BITMAP_WRITE_ERROR));
 465         /* Just in case these have been changed via sysfs: */
 466         sb->daemon_sleep = cpu_to_le32(bitmap->mddev->bitmap_info.daemon_sleep/HZ);
 467         sb->write_behind = cpu_to_le32(bitmap->mddev->bitmap_info.max_write_behind);
 468         /* This might have been changed by a reshape */
 469         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 470         sb->chunksize = cpu_to_le32(bitmap->mddev->bitmap_info.chunksize);
 471         sb->nodes = cpu_to_le32(bitmap->mddev->bitmap_info.nodes);
 472         sb->sectors_reserved = cpu_to_le32(bitmap->mddev->
 473                                            bitmap_info.space);
 474         kunmap_atomic(sb);
 475         write_page(bitmap, bitmap->storage.sb_page, 1);
 476 }
 477 EXPORT_SYMBOL(md_bitmap_update_sb);
 478
 479 /* print out the bitmap file superblock */
 480 void md_bitmap_print_sb(struct bitmap *bitmap)
 481 {
 482         bitmap_super_t *sb;
 483
 484         if (!bitmap || !bitmap->storage.sb_page)
 485                 return;
 486         sb = kmap_atomic(bitmap->storage.sb_page);
 487         pr_debug("%s: bitmap file superblock:\n", bmname(bitmap));
 488         pr_debug("         magic: %08x\n", le32_to_cpu(sb->magic));
 489         pr_debug("       version: %u\n", le32_to_cpu(sb->version));
 490         pr_debug("          uuid: %08x.%08x.%08x.%08x\n",
 491                  le32_to_cpu(*(__le32 *)(sb->uuid+0)),
 492                  le32_to_cpu(*(__le32 *)(sb->uuid+4)),
 493                  le32_to_cpu(*(__le32 *)(sb->uuid+8)),
 494                  le32_to_cpu(*(__le32 *)(sb->uuid+12)));
 495         pr_debug("        events: %llu\n",
 496                  (unsigned long long) le64_to_cpu(sb->events));
 497         pr_debug("events cleared: %llu\n",
 498                  (unsigned long long) le64_to_cpu(sb->events_cleared));
 499         pr_debug("         state: %08x\n", le32_to_cpu(sb->state));
 500         pr_debug("     chunksize: %u B\n", le32_to_cpu(sb->chunksize));
 501         pr_debug("  daemon sleep: %us\n", le32_to_cpu(sb->daemon_sleep));
 502         pr_debug("     sync size: %llu KB\n",
 503                  (unsigned long long)le64_to_cpu(sb->sync_size)/2);
 504         pr_debug("max write behind: %u\n", le32_to_cpu(sb->write_behind));
 505         kunmap_atomic(sb);
 506 }
 507
 508 /*
 509  * bitmap_new_disk_sb
 510  * @bitmap
 511  *
 512  * This function is somewhat the reverse of bitmap_read_sb.  bitmap_read_sb
 513  * reads and verifies the on-disk bitmap superblock and populates bitmap_info.
 514  * This function verifies 'bitmap_info' and populates the on-disk bitmap
 515  * structure, which is to be written to disk.
 516  *
 517  * Returns: 0 on success, -Exxx on error
 518  */
 519 static int md_bitmap_new_disk_sb(struct bitmap *bitmap)
 520 {
 521         bitmap_super_t *sb;
 522         unsigned long chunksize, daemon_sleep, write_behind;
 523
 524         bitmap->storage.sb_page = alloc_page(GFP_KERNEL | __GFP_ZERO);
 525         if (bitmap->storage.sb_page == NULL)
 526                 return -ENOMEM;
 527         bitmap->storage.sb_page->index = 0;
 528
 529         sb = kmap_atomic(bitmap->storage.sb_page);
 530
 531         sb->magic = cpu_to_le32(BITMAP_MAGIC);
 532         sb->version = cpu_to_le32(BITMAP_MAJOR_HI);
 533
 534         chunksize = bitmap->mddev->bitmap_info.chunksize;
 535         BUG_ON(!chunksize);
 536         if (!is_power_of_2(chunksize)) {
 537                 kunmap_atomic(sb);
 538                 pr_warn("bitmap chunksize not a power of 2\n");
 539                 return -EINVAL;
 540         }
 541         sb->chunksize = cpu_to_le32(chunksize);
 542
 543         daemon_sleep = bitmap->mddev->bitmap_info.daemon_sleep;
 544         if (!daemon_sleep || (daemon_sleep > MAX_SCHEDULE_TIMEOUT)) {
 545                 pr_debug("Choosing daemon_sleep default (5 sec)\n");
 546                 daemon_sleep = 5 * HZ;
 547         }
 548         sb->daemon_sleep = cpu_to_le32(daemon_sleep);
 549         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 550
 551         /*
 552          * FIXME: write_behind for RAID1.  If not specified, what
 553          * is a good choice?  We choose COUNTER_MAX / 2 arbitrarily.
 554          */
 555         write_behind = bitmap->mddev->bitmap_info.max_write_behind;
 556         if (write_behind > COUNTER_MAX)
 557                 write_behind = COUNTER_MAX / 2;
 558         sb->write_behind = cpu_to_le32(write_behind);
 559         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 560
 561         /* keep the array size field of the bitmap superblock up to date */
 562         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 563
 564         memcpy(sb->uuid, bitmap->mddev->uuid, 16);
 565
 566         set_bit(BITMAP_STALE, &bitmap->flags);
 567         sb->state = cpu_to_le32(bitmap->flags);
 568         bitmap->events_cleared = bitmap->mddev->events;
 569         sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
 570         bitmap->mddev->bitmap_info.nodes = 0;
 571
 572         kunmap_atomic(sb);
 573
 574         return 0;
 575 }
 576
 577 /* read the superblock from the bitmap file and initialize some bitmap fields */
 578 static int md_bitmap_read_sb(struct bitmap *bitmap)
 579 {
 580         char *reason = NULL;
 581         bitmap_super_t *sb;
 582         unsigned long chunksize, daemon_sleep, write_behind;
 583         unsigned long long events;
 584         int nodes = 0;
 585         unsigned long sectors_reserved = 0;
 586         int err = -EINVAL;
 587         struct page *sb_page;
 588         loff_t offset = bitmap->mddev->bitmap_info.offset;
 589
 590         if (!bitmap->storage.file && !bitmap->mddev->bitmap_info.offset) {
 591                 chunksize = 128 * 1024 * 1024;
 592                 daemon_sleep = 5 * HZ;
 593                 write_behind = 0;
 594                 set_bit(BITMAP_STALE, &bitmap->flags);
 595                 err = 0;
 596                 goto out_no_sb;
 597         }
 598         /* page 0 is the superblock, read it... */
 599         sb_page = alloc_page(GFP_KERNEL);
 600         if (!sb_page)
 601                 return -ENOMEM;
 602         bitmap->storage.sb_page = sb_page;
 603
 604 re_read:
 605         /* If cluster_slot is set, the cluster is setup */
 606         if (bitmap->cluster_slot >= 0) {
 607                 sector_t bm_blocks = bitmap->mddev->resync_max_sectors;
 608
 609                 bm_blocks = DIV_ROUND_UP_SECTOR_T(bm_blocks,
 610                            (bitmap->mddev->bitmap_info.chunksize >> 9));
 611                 /* bits to bytes */
 612                 bm_blocks = ((bm_blocks+7) >> 3) + sizeof(bitmap_super_t);
 613                 /* to 4k blocks */
 614                 bm_blocks = DIV_ROUND_UP_SECTOR_T(bm_blocks, 4096);
 615                 offset = bitmap->mddev->bitmap_info.offset + (bitmap->cluster_slot * (bm_blocks << 3));
 616                 pr_debug("%s:%d bm slot: %d offset: %llu\n", __func__, __LINE__,
 617                         bitmap->cluster_slot, offset);
 618         }
 619
 620         if (bitmap->storage.file) {
 621                 loff_t isize = i_size_read(bitmap->storage.file->f_mapping->host);
 622                 int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
 623
 624                 err = read_page(bitmap->storage.file, 0,
 625                                 bitmap, bytes, sb_page);
 626         } else {
 627                 err = read_sb_page(bitmap->mddev,
 628                                    offset,
 629                                    sb_page,
 630                                    0, sizeof(bitmap_super_t));
 631         }
 632         if (err)
 633                 return err;
 634
 635         err = -EINVAL;
 636         sb = kmap_atomic(sb_page);
 637
 638         chunksize = le32_to_cpu(sb->chunksize);
 639         daemon_sleep = le32_to_cpu(sb->daemon_sleep) * HZ;
 640         write_behind = le32_to_cpu(sb->write_behind);
 641         sectors_reserved = le32_to_cpu(sb->sectors_reserved);
 642
 643         /* verify that the bitmap-specific fields are valid */
 644         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
 645                 reason = "bad magic";
 646         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
 647                  le32_to_cpu(sb->version) > BITMAP_MAJOR_CLUSTERED)
 648                 reason = "unrecognized superblock version";
 649         else if (chunksize < 512)
 650                 reason = "bitmap chunksize too small";
 651         else if (!is_power_of_2(chunksize))
 652                 reason = "bitmap chunksize not a power of 2";
 653         else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT)
 654                 reason = "daemon sleep period out of range";
 655         else if (write_behind > COUNTER_MAX)
 656                 reason = "write-behind limit out of range (0 - 16383)";
 657         if (reason) {
 658                 pr_warn("%s: invalid bitmap file superblock: %s\n",
 659                         bmname(bitmap), reason);
 660                 goto out;
 661         }
 662
 663         /*
 664          * Setup nodes/clustername only if bitmap version is
 665          * cluster-compatible
 666          */
 667         if (sb->version == cpu_to_le32(BITMAP_MAJOR_CLUSTERED)) {
 668                 nodes = le32_to_cpu(sb->nodes);
 669                 strscpy(bitmap->mddev->bitmap_info.cluster_name,
 670                                 sb->cluster_name, 64);
 671         }
 672
 673         /* keep the array size field of the bitmap superblock up to date */
 674         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 675
 676         if (bitmap->mddev->persistent) {
 677                 /*
 678                  * We have a persistent array superblock, so compare the
 679                  * bitmap's UUID and event counter to the mddev's
 680                  */
 681                 if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
 682                         pr_warn("%s: bitmap superblock UUID mismatch\n",
 683                                 bmname(bitmap));
 684                         goto out;
 685                 }
 686                 events = le64_to_cpu(sb->events);
 687                 if (!nodes && (events < bitmap->mddev->events)) {
 688                         pr_warn("%s: bitmap file is out of date (%llu < %llu) -- forcing full recovery\n",
 689                                 bmname(bitmap), events,
 690                                 (unsigned long long) bitmap->mddev->events);
 691                         set_bit(BITMAP_STALE, &bitmap->flags);
 692                 }
 693         }
 694
 695         /* assign fields using values from superblock */
 696         bitmap->flags |= le32_to_cpu(sb->state);
 697         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
 698                 set_bit(BITMAP_HOSTENDIAN, &bitmap->flags);
 699         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
 700         err = 0;
 701
 702 out:
 703         kunmap_atomic(sb);
 704         if (err == 0 && nodes && (bitmap->cluster_slot < 0)) {
 705                 /* Assigning chunksize is required for "re_read" */
 706                 bitmap->mddev->bitmap_info.chunksize = chunksize;
 707                 err = md_setup_cluster(bitmap->mddev, nodes);
 708                 if (err) {
 709                         pr_warn("%s: Could not setup cluster service (%d)\n",
 710                                 bmname(bitmap), err);
 711                         goto out_no_sb;
 712                 }
 713                 bitmap->cluster_slot = md_cluster_ops->slot_number(bitmap->mddev);
 714                 goto re_read;
 715         }
 716
 717 out_no_sb:
 718         if (err == 0) {
 719                 if (test_bit(BITMAP_STALE, &bitmap->flags))
 720                         bitmap->events_cleared = bitmap->mddev->events;
 721                 bitmap->mddev->bitmap_info.chunksize = chunksize;
 722                 bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 723                 bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 724                 bitmap->mddev->bitmap_info.nodes = nodes;
 725                 if (bitmap->mddev->bitmap_info.space == 0 ||
 726                         bitmap->mddev->bitmap_info.space > sectors_reserved)
 727                         bitmap->mddev->bitmap_info.space = sectors_reserved;
 728         } else {
 729                 md_bitmap_print_sb(bitmap);
 730                 if (bitmap->cluster_slot < 0)
 731                         md_cluster_stop(bitmap->mddev);
 732         }
 733         return err;
 734 }
 735
 736 /*
 737  * general bitmap file operations
 738  */
 739
 740 /*
 741  * on-disk bitmap:
 742  *
 743  * Use one bit per "chunk" (block set). We do the disk I/O on the bitmap
 744  * file a page at a time. There's a superblock at the start of the file.
 745  */
 746 /* calculate the index of the page that contains this bit */
 747 static inline unsigned long file_page_index(struct bitmap_storage *store,
 748                                             unsigned long chunk)
 749 {
 750         if (store->sb_page)
 751                 chunk += sizeof(bitmap_super_t) << 3;
 752         return chunk >> PAGE_BIT_SHIFT;
 753 }
 754
 755 /* calculate the (bit) offset of this bit within a page */
 756 static inline unsigned long file_page_offset(struct bitmap_storage *store,
 757                                              unsigned long chunk)
 758 {
 759         if (store->sb_page)
 760                 chunk += sizeof(bitmap_super_t) << 3;
 761         return chunk & (PAGE_BITS - 1);
 762 }
 763
 764 /*
 765  * return a pointer to the page in the filemap that contains the given bit
 766  *
 767  */
 768 static inline struct page *filemap_get_page(struct bitmap_storage *store,
 769                                             unsigned long chunk)
 770 {
 771         if (file_page_index(store, chunk) >= store->file_pages)
 772                 return NULL;
 773         return store->filemap[file_page_index(store, chunk)];
 774 }
 775
 776 static int md_bitmap_storage_alloc(struct bitmap_storage *store,
 777                                    unsigned long chunks, int with_super,
 778                                    int slot_number)
 779 {
 780         int pnum, offset = 0;
 781         unsigned long num_pages;
 782         unsigned long bytes;
 783
 784         bytes = DIV_ROUND_UP(chunks, 8);
 785         if (with_super)
 786                 bytes += sizeof(bitmap_super_t);
 787
 788         num_pages = DIV_ROUND_UP(bytes, PAGE_SIZE);
 789         offset = slot_number * num_pages;
 790
 791         store->filemap = kmalloc_array(num_pages, sizeof(struct page *),
 792                                        GFP_KERNEL);
 793         if (!store->filemap)
 794                 return -ENOMEM;
 795
 796         if (with_super && !store->sb_page) {
 797                 store->sb_page = alloc_page(GFP_KERNEL|__GFP_ZERO);
 798                 if (store->sb_page == NULL)
 799                         return -ENOMEM;
 800         }
 801
 802         pnum = 0;
 803         if (store->sb_page) {
 804                 store->filemap[0] = store->sb_page;
 805                 pnum = 1;
 806                 store->sb_page->index = offset;
 807         }
 808
 809         for ( ; pnum < num_pages; pnum++) {
 810                 store->filemap[pnum] = alloc_page(GFP_KERNEL|__GFP_ZERO);
 811                 if (!store->filemap[pnum]) {
 812                         store->file_pages = pnum;
 813                         return -ENOMEM;
 814                 }
 815                 store->filemap[pnum]->index = pnum + offset;
 816         }
 817         store->file_pages = pnum;
 818
 819         /* We need 4 bits per page, rounded up to a multiple
 820          * of sizeof(unsigned long) */
 821         store->filemap_attr = kzalloc(
 822                 roundup(DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
 823                 GFP_KERNEL);
 824         if (!store->filemap_attr)
 825                 return -ENOMEM;
 826
 827         store->bytes = bytes;
 828
 829         return 0;
 830 }
 831
 832 static void md_bitmap_file_unmap(struct bitmap_storage *store)
 833 {
 834         struct page **map, *sb_page;
 835         int pages;
 836         struct file *file;
 837
 838         file = store->file;
 839         map = store->filemap;
 840         pages = store->file_pages;
 841         sb_page = store->sb_page;
 842
 843         while (pages--)
 844                 if (map[pages] != sb_page) /* 0 is sb_page, release it below */
 845                         free_buffers(map[pages]);
 846         kfree(map);
 847         kfree(store->filemap_attr);
 848
 849         if (sb_page)
 850                 free_buffers(sb_page);
 851
 852         if (file) {
 853                 struct inode *inode = file_inode(file);
 854                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
 855                 fput(file);
 856         }
 857 }
 858
 859 /*
 860  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
 861  * then it is no longer reliable, so we stop using it and we mark the file
 862  * as failed in the superblock
 863  */
 864 static void md_bitmap_file_kick(struct bitmap *bitmap)
 865 {
 866         char *path, *ptr = NULL;
 867
 868         if (!test_and_set_bit(BITMAP_STALE, &bitmap->flags)) {
 869                 md_bitmap_update_sb(bitmap);
 870
 871                 if (bitmap->storage.file) {
 872                         path = kmalloc(PAGE_SIZE, GFP_KERNEL);
 873                         if (path)
 874                                 ptr = file_path(bitmap->storage.file,
 875                                              path, PAGE_SIZE);
 876
 877                         pr_warn("%s: kicking failed bitmap file %s from array!\n",
 878                                 bmname(bitmap), IS_ERR(ptr) ? "" : ptr);
 879
 880                         kfree(path);
 881                 } else
 882                         pr_warn("%s: disabling internal bitmap due to errors\n",
 883                                 bmname(bitmap));
 884         }
 885 }
 886
 887 enum bitmap_page_attr {
 888         BITMAP_PAGE_DIRTY = 0,     /* there are set bits that need to be synced */
 889         BITMAP_PAGE_PENDING = 1,   /* there are bits that are being cleaned.
 890                                     * i.e. counter is 1 or 2. */
 891         BITMAP_PAGE_NEEDWRITE = 2, /* there are cleared bits that need to be synced */
 892 };
 893
 894 static inline void set_page_attr(struct bitmap *bitmap, int pnum,
 895                                  enum bitmap_page_attr attr)
 896 {
 897         set_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 898 }
 899
 900 static inline void clear_page_attr(struct bitmap *bitmap, int pnum,
 901                                    enum bitmap_page_attr attr)
 902 {
 903         clear_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 904 }
 905
 906 static inline int test_page_attr(struct bitmap *bitmap, int pnum,
 907                                  enum bitmap_page_attr attr)
 908 {
 909         return test_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 910 }
 911
 912 static inline int test_and_clear_page_attr(struct bitmap *bitmap, int pnum,
 913                                            enum bitmap_page_attr attr)
 914 {
 915         return test_and_clear_bit((pnum<<2) + attr,
 916                                   bitmap->storage.filemap_attr);
 917 }
 918 /*
 919  * bitmap_file_set_bit -- called before performing a write to the md device
 920  * to set (and eventually sync) a particular bit in the bitmap file
 921  *
 922  * we set the bit immediately, then we record the page number so that
 923  * when an unplug occurs, we can flush the dirty pages out to disk
 924  */
 925 static void md_bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 926 {
 927         unsigned long bit;
 928         struct page *page;
 929         void *kaddr;
 930         unsigned long chunk = block >> bitmap->counts.chunkshift;
 931         struct bitmap_storage *store = &bitmap->storage;
 932         unsigned long node_offset = 0;
 933
 934         if (mddev_is_clustered(bitmap->mddev))
 935                 node_offset = bitmap->cluster_slot * store->file_pages;
 936
 937         page = filemap_get_page(&bitmap->storage, chunk);
 938         if (!page)
 939                 return;
 940         bit = file_page_offset(&bitmap->storage, chunk);
 941
 942         /* set the bit */
 943         kaddr = kmap_atomic(page);
 944         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
 945                 set_bit(bit, kaddr);
 946         else
 947                 set_bit_le(bit, kaddr);
 948         kunmap_atomic(kaddr);
 949         pr_debug("set file bit %lu page %lu\n", bit, page->index);
 950         /* record page number so it gets flushed to disk when unplug occurs */
 951         set_page_attr(bitmap, page->index - node_offset, BITMAP_PAGE_DIRTY);
 952 }
 953
 954 static void md_bitmap_file_clear_bit(struct bitmap *bitmap, sector_t block)
 955 {
 956         unsigned long bit;
 957         struct page *page;
 958         void *paddr;
 959         unsigned long chunk = block >> bitmap->counts.chunkshift;
 960         struct bitmap_storage *store = &bitmap->storage;
 961         unsigned long node_offset = 0;
 962
 963         if (mddev_is_clustered(bitmap->mddev))
 964                 node_offset = bitmap->cluster_slot * store->file_pages;
 965
 966         page = filemap_get_page(&bitmap->storage, chunk);
 967         if (!page)
 968                 return;
 969         bit = file_page_offset(&bitmap->storage, chunk);
 970         paddr = kmap_atomic(page);
 971         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
 972                 clear_bit(bit, paddr);
 973         else
 974                 clear_bit_le(bit, paddr);
 975         kunmap_atomic(paddr);
 976         if (!test_page_attr(bitmap, page->index - node_offset, BITMAP_PAGE_NEEDWRITE)) {
 977                 set_page_attr(bitmap, page->index - node_offset, BITMAP_PAGE_PENDING);
 978                 bitmap->allclean = 0;
 979         }
 980 }
 981
 982 static int md_bitmap_file_test_bit(struct bitmap *bitmap, sector_t block)
 983 {
 984         unsigned long bit;
 985         struct page *page;
 986         void *paddr;
 987         unsigned long chunk = block >> bitmap->counts.chunkshift;
 988         int set = 0;
 989
 990         page = filemap_get_page(&bitmap->storage, chunk);
 991         if (!page)
 992                 return -EINVAL;
 993         bit = file_page_offset(&bitmap->storage, chunk);
 994         paddr = kmap_atomic(page);
 995         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
 996                 set = test_bit(bit, paddr);
 997         else
 998                 set = test_bit_le(bit, paddr);
 999         kunmap_atomic(paddr);
1000         return set;
1001 }
1002
1003
1004 /* this gets called when the md device is ready to unplug its underlying
1005  * (slave) device queues -- before we let any writes go down, we need to
1006  * sync the dirty pages of the bitmap file to disk */
1007 void md_bitmap_unplug(struct bitmap *bitmap)
1008 {
1009         unsigned long i;
1010         int dirty, need_write;
1011         int writing = 0;
1012
1013         if (!bitmap || !bitmap->storage.filemap ||
1014             test_bit(BITMAP_STALE, &bitmap->flags))
1015                 return;
1016
1017         /* look at each page to see if there are any set bits that need to be
1018          * flushed out to disk */
1019         for (i = 0; i < bitmap->storage.file_pages; i++) {
1020                 dirty = test_and_clear_page_attr(bitmap, i, BITMAP_PAGE_DIRTY);
1021                 need_write = test_and_clear_page_attr(bitmap, i,
1022                                                       BITMAP_PAGE_NEEDWRITE);
1023                 if (dirty || need_write) {
1024                         if (!writing) {
1025                                 md_bitmap_wait_writes(bitmap);
1026                                 if (bitmap->mddev->queue)
1027                                         blk_add_trace_msg(bitmap->mddev->queue,
1028                                                           "md bitmap_unplug");
1029                         }
1030                         clear_page_attr(bitmap, i, BITMAP_PAGE_PENDING);
1031                         write_page(bitmap, bitmap->storage.filemap[i], 0);
1032                         writing = 1;
1033                 }
1034         }
1035         if (writing)
1036                 md_bitmap_wait_writes(bitmap);
1037
1038         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
1039                 md_bitmap_file_kick(bitmap);
1040 }
1041 EXPORT_SYMBOL(md_bitmap_unplug);
1042
1043 static void md_bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
1044 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
1045  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
1046  * memory mapping of the bitmap file
1047  * Special cases:
1048  *   if there's no bitmap file, or if the bitmap file had been
1049  *   previously kicked from the array, we mark all the bits as
1050  *   1's in order to cause a full resync.
1051  *
1052  * We ignore all bits for sectors that end earlier than 'start'.
1053  * This is used when reading an out-of-date bitmap...
1054  */
1055 static int md_bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
1056 {
1057         unsigned long i, chunks, index, oldindex, bit, node_offset = 0;
1058         struct page *page = NULL;
1059         unsigned long bit_cnt = 0;
1060         struct file *file;
1061         unsigned long offset;
1062         int outofdate;
1063         int ret = -ENOSPC;
1064         void *paddr;
1065         struct bitmap_storage *store = &bitmap->storage;
1066
1067         chunks = bitmap->counts.chunks;
1068         file = store->file;
1069
1070         if (!file && !bitmap->mddev->bitmap_info.offset) {
1071                 /* No permanent bitmap - fill with '1s'. */
1072                 store->filemap = NULL;
1073                 store->file_pages = 0;
1074                 for (i = 0; i < chunks ; i++) {
1075                         /* if the disk bit is set, set the memory bit */
1076                         int needed = ((sector_t)(i+1) << (bitmap->counts.chunkshift)
1077                                       >= start);
1078                         md_bitmap_set_memory_bits(bitmap,
1079                                                   (sector_t)i << bitmap->counts.chunkshift,
1080                                                   needed);
1081                 }
1082                 return 0;
1083         }
1084
1085         outofdate = test_bit(BITMAP_STALE, &bitmap->flags);
1086         if (outofdate)
1087                 pr_warn("%s: bitmap file is out of date, doing full recovery\n", bmname(bitmap));
1088
1089         if (file && i_size_read(file->f_mapping->host) < store->bytes) {
1090                 pr_warn("%s: bitmap file too short %lu < %lu\n",
1091                         bmname(bitmap),
1092                         (unsigned long) i_size_read(file->f_mapping->host),
1093                         store->bytes);
1094                 goto err;
1095         }
1096
1097         oldindex = ~0L;
1098         offset = 0;
1099         if (!bitmap->mddev->bitmap_info.external)
1100                 offset = sizeof(bitmap_super_t);
1101
1102         if (mddev_is_clustered(bitmap->mddev))
1103                 node_offset = bitmap->cluster_slot * (DIV_ROUND_UP(store->bytes, PAGE_SIZE));
1104
1105         for (i = 0; i < chunks; i++) {
1106                 int b;
1107                 index = file_page_index(&bitmap->storage, i);
1108                 bit = file_page_offset(&bitmap->storage, i);
1109                 if (index != oldindex) { /* this is a new page, read it in */
1110                         int count;
1111                         /* unmap the old page, we're done with it */
1112                         if (index == store->file_pages-1)
1113                                 count = store->bytes - index * PAGE_SIZE;
1114                         else
1115                                 count = PAGE_SIZE;
1116                         page = store->filemap[index];
1117                         if (file)
1118                                 ret = read_page(file, index, bitmap,
1119                                                 count, page);
1120                         else
1121                                 ret = read_sb_page(
1122                                         bitmap->mddev,
1123                                         bitmap->mddev->bitmap_info.offset,
1124                                         page,
1125                                         index + node_offset, count);
1126
1127                         if (ret)
1128                                 goto err;
1129
1130                         oldindex = index;
1131
1132                         if (outofdate) {
1133                                 /*
1134                                  * if bitmap is out of date, dirty the
1135                                  * whole page and write it out
1136                                  */
1137                                 paddr = kmap_atomic(page);
1138                                 memset(paddr + offset, 0xff,
1139                                        PAGE_SIZE - offset);
1140                                 kunmap_atomic(paddr);
1141                                 write_page(bitmap, page, 1);
1142
1143                                 ret = -EIO;
1144                                 if (test_bit(BITMAP_WRITE_ERROR,
1145                                              &bitmap->flags))
1146                                         goto err;
1147                         }
1148                 }
1149                 paddr = kmap_atomic(page);
1150                 if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
1151                         b = test_bit(bit, paddr);
1152                 else
1153                         b = test_bit_le(bit, paddr);
1154                 kunmap_atomic(paddr);
1155                 if (b) {
1156                         /* if the disk bit is set, set the memory bit */
1157                         int needed = ((sector_t)(i+1) << bitmap->counts.chunkshift
1158                                       >= start);
1159                         md_bitmap_set_memory_bits(bitmap,
1160                                                   (sector_t)i << bitmap->counts.chunkshift,
1161                                                   needed);
1162                         bit_cnt++;
1163                 }
1164                 offset = 0;
1165         }
1166
1167         pr_debug("%s: bitmap initialized from disk: read %lu pages, set %lu of %lu bits\n",
1168                  bmname(bitmap), store->file_pages,
1169                  bit_cnt, chunks);
1170
1171         return 0;
1172
1173  err:
1174         pr_warn("%s: bitmap initialisation failed: %d\n",
1175                 bmname(bitmap), ret);
1176         return ret;
1177 }
1178
1179 void md_bitmap_write_all(struct bitmap *bitmap)
1180 {
1181         /* We don't actually write all bitmap blocks here,
1182          * just flag them as needing to be written
1183          */
1184         int i;
1185
1186         if (!bitmap || !bitmap->storage.filemap)
1187                 return;
1188         if (bitmap->storage.file)
1189                 /* Only one copy, so nothing needed */
1190                 return;
1191
1192         for (i = 0; i < bitmap->storage.file_pages; i++)
1193                 set_page_attr(bitmap, i,
1194                               BITMAP_PAGE_NEEDWRITE);
1195         bitmap->allclean = 0;
1196 }
1197
1198 static void md_bitmap_count_page(struct bitmap_counts *bitmap,
1199                                  sector_t offset, int inc)
1200 {
1201         sector_t chunk = offset >> bitmap->chunkshift;
1202         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1203         bitmap->bp[page].count += inc;
1204         md_bitmap_checkfree(bitmap, page);
1205 }
1206
1207 static void md_bitmap_set_pending(struct bitmap_counts *bitmap, sector_t offset)
1208 {
1209         sector_t chunk = offset >> bitmap->chunkshift;
1210         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1211         struct bitmap_page *bp = &bitmap->bp[page];
1212
1213         if (!bp->pending)
1214                 bp->pending = 1;
1215 }
1216
1217 static bitmap_counter_t *md_bitmap_get_counter(struct bitmap_counts *bitmap,
1218                                                sector_t offset, sector_t *blocks,
1219                                                int create);
1220
1221 /*
1222  * bitmap daemon -- periodically wakes up to clean bits and flush pages
1223  *                      out to disk
1224  */
1225
1226 void md_bitmap_daemon_work(struct mddev *mddev)
1227 {
1228         struct bitmap *bitmap;
1229         unsigned long j;
1230         unsigned long nextpage;
1231         sector_t blocks;
1232         struct bitmap_counts *counts;
1233
1234         /* Use a mutex to guard daemon_work against
1235          * bitmap_destroy.
1236          */
1237         mutex_lock(&mddev->bitmap_info.mutex);
1238         bitmap = mddev->bitmap;
1239         if (bitmap == NULL) {
1240                 mutex_unlock(&mddev->bitmap_info.mutex);
1241                 return;
1242         }
1243         if (time_before(jiffies, bitmap->daemon_lastrun
1244                         + mddev->bitmap_info.daemon_sleep))
1245                 goto done;
1246
1247         bitmap->daemon_lastrun = jiffies;
1248         if (bitmap->allclean) {
1249                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1250                 goto done;
1251         }
1252         bitmap->allclean = 1;
1253
1254         if (bitmap->mddev->queue)
1255                 blk_add_trace_msg(bitmap->mddev->queue,
1256                                   "md bitmap_daemon_work");
1257
1258         /* Any file-page which is PENDING now needs to be written.
1259          * So set NEEDWRITE now, then after we make any last-minute changes
1260          * we will write it.
1261          */
1262         for (j = 0; j < bitmap->storage.file_pages; j++)
1263                 if (test_and_clear_page_attr(bitmap, j,
1264                                              BITMAP_PAGE_PENDING))
1265                         set_page_attr(bitmap, j,
1266                                       BITMAP_PAGE_NEEDWRITE);
1267
1268         if (bitmap->need_sync &&
1269             mddev->bitmap_info.external == 0) {
1270                 /* Arrange for superblock update as well as
1271                  * other changes */
1272                 bitmap_super_t *sb;
1273                 bitmap->need_sync = 0;
1274                 if (bitmap->storage.filemap) {
1275                         sb = kmap_atomic(bitmap->storage.sb_page);
1276                         sb->events_cleared =
1277                                 cpu_to_le64(bitmap->events_cleared);
1278                         kunmap_atomic(sb);
1279                         set_page_attr(bitmap, 0,
1280                                       BITMAP_PAGE_NEEDWRITE);
1281                 }
1282         }
1283         /* Now look at the bitmap counters and if any are '2' or '1',
1284          * decrement and handle accordingly.
1285          */
1286         counts = &bitmap->counts;
1287         spin_lock_irq(&counts->lock);
1288         nextpage = 0;
1289         for (j = 0; j < counts->chunks; j++) {
1290                 bitmap_counter_t *bmc;
1291                 sector_t  block = (sector_t)j << counts->chunkshift;
1292
1293                 if (j == nextpage) {
1294                         nextpage += PAGE_COUNTER_RATIO;
1295                         if (!counts->bp[j >> PAGE_COUNTER_SHIFT].pending) {
1296                                 j |= PAGE_COUNTER_MASK;
1297                                 continue;
1298                         }
1299                         counts->bp[j >> PAGE_COUNTER_SHIFT].pending = 0;
1300                 }
1301
1302                 bmc = md_bitmap_get_counter(counts, block, &blocks, 0);
1303                 if (!bmc) {
1304                         j |= PAGE_COUNTER_MASK;
1305                         continue;
1306                 }
1307                 if (*bmc == 1 && !bitmap->need_sync) {
1308                         /* We can clear the bit */
1309                         *bmc = 0;
1310                         md_bitmap_count_page(counts, block, -1);
1311                         md_bitmap_file_clear_bit(bitmap, block);
1312                 } else if (*bmc && *bmc <= 2) {
1313                         *bmc = 1;
1314                         md_bitmap_set_pending(counts, block);
1315                         bitmap->allclean = 0;
1316                 }
1317         }
1318         spin_unlock_irq(&counts->lock);
1319
1320         md_bitmap_wait_writes(bitmap);
1321         /* Now start writeout on any page in NEEDWRITE that isn't DIRTY.
1322          * DIRTY pages need to be written by bitmap_unplug so it can wait
1323          * for them.
1324          * If we find any DIRTY page we stop there and let bitmap_unplug
1325          * handle all the rest.  This is important in the case where
1326          * the first blocking holds the superblock and it has been updated.
1327          * We mustn't write any other blocks before the superblock.
1328          */
1329         for (j = 0;
1330              j < bitmap->storage.file_pages
1331                      && !test_bit(BITMAP_STALE, &bitmap->flags);
1332              j++) {
1333                 if (test_page_attr(bitmap, j,
1334                                    BITMAP_PAGE_DIRTY))
1335                         /* bitmap_unplug will handle the rest */
1336                         break;
1337                 if (bitmap->storage.filemap &&
1338                     test_and_clear_page_attr(bitmap, j,
1339                                              BITMAP_PAGE_NEEDWRITE)) {
1340                         write_page(bitmap, bitmap->storage.filemap[j], 0);
1341                 }
1342         }
1343
1344  done:
1345         if (bitmap->allclean == 0)
1346                 mddev->thread->timeout =
1347                         mddev->bitmap_info.daemon_sleep;
1348         mutex_unlock(&mddev->bitmap_info.mutex);
1349 }
1350
1351 static bitmap_counter_t *md_bitmap_get_counter(struct bitmap_counts *bitmap,
1352                                                sector_t offset, sector_t *blocks,
1353                                                int create)
1354 __releases(bitmap->lock)
1355 __acquires(bitmap->lock)
1356 {
1357         /* If 'create', we might release the lock and reclaim it.
1358          * The lock must have been taken with interrupts enabled.
1359          * If !create, we don't release the lock.
1360          */
1361         sector_t chunk = offset >> bitmap->chunkshift;
1362         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1363         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1364         sector_t csize;
1365         int err;
1366
1367         err = md_bitmap_checkpage(bitmap, page, create, 0);
1368
1369         if (bitmap->bp[page].hijacked ||
1370             bitmap->bp[page].map == NULL)
1371                 csize = ((sector_t)1) << (bitmap->chunkshift +
1372                                           PAGE_COUNTER_SHIFT);
1373         else
1374                 csize = ((sector_t)1) << bitmap->chunkshift;
1375         *blocks = csize - (offset & (csize - 1));
1376
1377         if (err < 0)
1378                 return NULL;
1379
1380         /* now locked ... */
1381
1382         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1383                 /* should we use the first or second counter field
1384                  * of the hijacked pointer? */
1385                 int hi = (pageoff > PAGE_COUNTER_MASK);
1386                 return  &((bitmap_counter_t *)
1387                           &bitmap->bp[page].map)[hi];
1388         } else /* page is allocated */
1389                 return (bitmap_counter_t *)
1390                         &(bitmap->bp[page].map[pageoff]);
1391 }
1392
1393 int md_bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1394 {
1395         if (!bitmap)
1396                 return 0;
1397
1398         if (behind) {
1399                 int bw;
1400                 atomic_inc(&bitmap->behind_writes);
1401                 bw = atomic_read(&bitmap->behind_writes);
1402                 if (bw > bitmap->behind_writes_used)
1403                         bitmap->behind_writes_used = bw;
1404
1405                 pr_debug("inc write-behind count %d/%lu\n",
1406                          bw, bitmap->mddev->bitmap_info.max_write_behind);
1407         }
1408
1409         while (sectors) {
1410                 sector_t blocks;
1411                 bitmap_counter_t *bmc;
1412
1413                 spin_lock_irq(&bitmap->counts.lock);
1414                 bmc = md_bitmap_get_counter(&bitmap->counts, offset, &blocks, 1);
1415                 if (!bmc) {
1416                         spin_unlock_irq(&bitmap->counts.lock);
1417                         return 0;
1418                 }
1419
1420                 if (unlikely(COUNTER(*bmc) == COUNTER_MAX)) {
1421                         DEFINE_WAIT(__wait);
1422                         /* note that it is safe to do the prepare_to_wait
1423                          * after the test as long as we do it before dropping
1424                          * the spinlock.
1425                          */
1426                         prepare_to_wait(&bitmap->overflow_wait, &__wait,
1427                                         TASK_UNINTERRUPTIBLE);
1428                         spin_unlock_irq(&bitmap->counts.lock);
1429                         schedule();
1430                         finish_wait(&bitmap->overflow_wait, &__wait);
1431                         continue;
1432                 }
1433
1434                 switch (*bmc) {
1435                 case 0:
1436                         md_bitmap_file_set_bit(bitmap, offset);
1437                         md_bitmap_count_page(&bitmap->counts, offset, 1);
1438                         fallthrough;
1439                 case 1:
1440                         *bmc = 2;
1441                 }
1442
1443                 (*bmc)++;
1444
1445                 spin_unlock_irq(&bitmap->counts.lock);
1446
1447                 offset += blocks;
1448                 if (sectors > blocks)
1449                         sectors -= blocks;
1450                 else
1451                         sectors = 0;
1452         }
1453         return 0;
1454 }
1455 EXPORT_SYMBOL(md_bitmap_startwrite);
1456
1457 void md_bitmap_endwrite(struct bitmap *bitmap, sector_t offset,
1458                         unsigned long sectors, int success, int behind)
1459 {
1460         if (!bitmap)
1461                 return;
1462         if (behind) {
1463                 if (atomic_dec_and_test(&bitmap->behind_writes))
1464                         wake_up(&bitmap->behind_wait);
1465                 pr_debug("dec write-behind count %d/%lu\n",
1466                          atomic_read(&bitmap->behind_writes),
1467                          bitmap->mddev->bitmap_info.max_write_behind);
1468         }
1469
1470         while (sectors) {
1471                 sector_t blocks;
1472                 unsigned long flags;
1473                 bitmap_counter_t *bmc;
1474
1475                 spin_lock_irqsave(&bitmap->counts.lock, flags);
1476                 bmc = md_bitmap_get_counter(&bitmap->counts, offset, &blocks, 0);
1477                 if (!bmc) {
1478                         spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1479                         return;
1480                 }
1481
1482                 if (success && !bitmap->mddev->degraded &&
1483                     bitmap->events_cleared < bitmap->mddev->events) {
1484                         bitmap->events_cleared = bitmap->mddev->events;
1485                         bitmap->need_sync = 1;
1486                         sysfs_notify_dirent_safe(bitmap->sysfs_can_clear);
1487                 }
1488
1489                 if (!success && !NEEDED(*bmc))
1490                         *bmc |= NEEDED_MASK;
1491
1492                 if (COUNTER(*bmc) == COUNTER_MAX)
1493                         wake_up(&bitmap->overflow_wait);
1494
1495                 (*bmc)--;
1496                 if (*bmc <= 2) {
1497                         md_bitmap_set_pending(&bitmap->counts, offset);
1498                         bitmap->allclean = 0;
1499                 }
1500                 spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1501                 offset += blocks;
1502                 if (sectors > blocks)
1503                         sectors -= blocks;
1504                 else
1505                         sectors = 0;
1506         }
1507 }
1508 EXPORT_SYMBOL(md_bitmap_endwrite);
1509
1510 static int __bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1511                                int degraded)
1512 {
1513         bitmap_counter_t *bmc;
1514         int rv;
1515         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1516                 *blocks = 1024;
1517                 return 1; /* always resync if no bitmap */
1518         }
1519         spin_lock_irq(&bitmap->counts.lock);
1520         bmc = md_bitmap_get_counter(&bitmap->counts, offset, blocks, 0);
1521         rv = 0;
1522         if (bmc) {
1523                 /* locked */
1524                 if (RESYNC(*bmc))
1525                         rv = 1;
1526                 else if (NEEDED(*bmc)) {
1527                         rv = 1;
1528                         if (!degraded) { /* don't set/clear bits if degraded */
1529                                 *bmc |= RESYNC_MASK;
1530                                 *bmc &= ~NEEDED_MASK;
1531                         }
1532                 }
1533         }
1534         spin_unlock_irq(&bitmap->counts.lock);
1535         return rv;
1536 }
1537
1538 int md_bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1539                          int degraded)
1540 {
1541         /* bitmap_start_sync must always report on multiples of whole
1542          * pages, otherwise resync (which is very PAGE_SIZE based) will
1543          * get confused.
1544          * So call __bitmap_start_sync repeatedly (if needed) until
1545          * At least PAGE_SIZE>>9 blocks are covered.
1546          * Return the 'or' of the result.
1547          */
1548         int rv = 0;
1549         sector_t blocks1;
1550
1551         *blocks = 0;
1552         while (*blocks < (PAGE_SIZE>>9)) {
1553                 rv |= __bitmap_start_sync(bitmap, offset,
1554                                           &blocks1, degraded);
1555                 offset += blocks1;
1556                 *blocks += blocks1;
1557         }
1558         return rv;
1559 }
1560 EXPORT_SYMBOL(md_bitmap_start_sync);
1561
1562 void md_bitmap_end_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks, int aborted)
1563 {
1564         bitmap_counter_t *bmc;
1565         unsigned long flags;
1566
1567         if (bitmap == NULL) {
1568                 *blocks = 1024;
1569                 return;
1570         }
1571         spin_lock_irqsave(&bitmap->counts.lock, flags);
1572         bmc = md_bitmap_get_counter(&bitmap->counts, offset, blocks, 0);
1573         if (bmc == NULL)
1574                 goto unlock;
1575         /* locked */
1576         if (RESYNC(*bmc)) {
1577                 *bmc &= ~RESYNC_MASK;
1578
1579                 if (!NEEDED(*bmc) && aborted)
1580                         *bmc |= NEEDED_MASK;
1581                 else {
1582                         if (*bmc <= 2) {
1583                                 md_bitmap_set_pending(&bitmap->counts, offset);
1584                                 bitmap->allclean = 0;
1585                         }
1586                 }
1587         }
1588  unlock:
1589         spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1590 }
1591 EXPORT_SYMBOL(md_bitmap_end_sync);
1592
1593 void md_bitmap_close_sync(struct bitmap *bitmap)
1594 {
1595         /* Sync has finished, and any bitmap chunks that weren't synced
1596          * properly have been aborted.  It remains to us to clear the
1597          * RESYNC bit wherever it is still on
1598          */
1599         sector_t sector = 0;
1600         sector_t blocks;
1601         if (!bitmap)
1602                 return;
1603         while (sector < bitmap->mddev->resync_max_sectors) {
1604                 md_bitmap_end_sync(bitmap, sector, &blocks, 0);
1605                 sector += blocks;
1606         }
1607 }
1608 EXPORT_SYMBOL(md_bitmap_close_sync);
1609
1610 void md_bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector, bool force)
1611 {
1612         sector_t s = 0;
1613         sector_t blocks;
1614
1615         if (!bitmap)
1616                 return;
1617         if (sector == 0) {
1618                 bitmap->last_end_sync = jiffies;
1619                 return;
1620         }
1621         if (!force && time_before(jiffies, (bitmap->last_end_sync
1622                                   + bitmap->mddev->bitmap_info.daemon_sleep)))
1623                 return;
1624         wait_event(bitmap->mddev->recovery_wait,
1625                    atomic_read(&bitmap->mddev->recovery_active) == 0);
1626
1627         bitmap->mddev->curr_resync_completed = sector;
1628         set_bit(MD_SB_CHANGE_CLEAN, &bitmap->mddev->sb_flags);
1629         sector &= ~((1ULL << bitmap->counts.chunkshift) - 1);
1630         s = 0;
1631         while (s < sector && s < bitmap->mddev->resync_max_sectors) {
1632                 md_bitmap_end_sync(bitmap, s, &blocks, 0);
1633                 s += blocks;
1634         }
1635         bitmap->last_end_sync = jiffies;
1636         sysfs_notify_dirent_safe(bitmap->mddev->sysfs_completed);
1637 }
1638 EXPORT_SYMBOL(md_bitmap_cond_end_sync);
1639
1640 void md_bitmap_sync_with_cluster(struct mddev *mddev,
1641                               sector_t old_lo, sector_t old_hi,
1642                               sector_t new_lo, sector_t new_hi)
1643 {
1644         struct bitmap *bitmap = mddev->bitmap;
1645         sector_t sector, blocks = 0;
1646
1647         for (sector = old_lo; sector < new_lo; ) {
1648                 md_bitmap_end_sync(bitmap, sector, &blocks, 0);
1649                 sector += blocks;
1650         }
1651         WARN((blocks > new_lo) && old_lo, "alignment is not correct for lo\n");
1652
1653         for (sector = old_hi; sector < new_hi; ) {
1654                 md_bitmap_start_sync(bitmap, sector, &blocks, 0);
1655                 sector += blocks;
1656         }
1657         WARN((blocks > new_hi) && old_hi, "alignment is not correct for hi\n");
1658 }
1659 EXPORT_SYMBOL(md_bitmap_sync_with_cluster);
1660
1661 static void md_bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1662 {
1663         /* For each chunk covered by any of these sectors, set the
1664          * counter to 2 and possibly set resync_needed.  They should all
1665          * be 0 at this point
1666          */
1667
1668         sector_t secs;
1669         bitmap_counter_t *bmc;
1670         spin_lock_irq(&bitmap->counts.lock);
1671         bmc = md_bitmap_get_counter(&bitmap->counts, offset, &secs, 1);
1672         if (!bmc) {
1673                 spin_unlock_irq(&bitmap->counts.lock);
1674                 return;
1675         }
1676         if (!*bmc) {
1677                 *bmc = 2;
1678                 md_bitmap_count_page(&bitmap->counts, offset, 1);
1679                 md_bitmap_set_pending(&bitmap->counts, offset);
1680                 bitmap->allclean = 0;
1681         }
1682         if (needed)
1683                 *bmc |= NEEDED_MASK;
1684         spin_unlock_irq(&bitmap->counts.lock);
1685 }
1686
1687 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
1688 void md_bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1689 {
1690         unsigned long chunk;
1691
1692         for (chunk = s; chunk <= e; chunk++) {
1693                 sector_t sec = (sector_t)chunk << bitmap->counts.chunkshift;
1694                 md_bitmap_set_memory_bits(bitmap, sec, 1);
1695                 md_bitmap_file_set_bit(bitmap, sec);
1696                 if (sec < bitmap->mddev->recovery_cp)
1697                         /* We are asserting that the array is dirty,
1698                          * so move the recovery_cp address back so
1699                          * that it is obvious that it is dirty
1700                          */
1701                         bitmap->mddev->recovery_cp = sec;
1702         }
1703 }
1704
1705 /*
1706  * flush out any pending updates
1707  */
1708 void md_bitmap_flush(struct mddev *mddev)
1709 {
1710         struct bitmap *bitmap = mddev->bitmap;
1711         long sleep;
1712
1713         if (!bitmap) /* there was no bitmap */
1714                 return;
1715
1716         /* run the daemon_work three time to ensure everything is flushed
1717          * that can be
1718          */
1719         sleep = mddev->bitmap_info.daemon_sleep * 2;
1720         bitmap->daemon_lastrun -= sleep;
1721         md_bitmap_daemon_work(mddev);
1722         bitmap->daemon_lastrun -= sleep;
1723         md_bitmap_daemon_work(mddev);
1724         bitmap->daemon_lastrun -= sleep;
1725         md_bitmap_daemon_work(mddev);
1726         if (mddev->bitmap_info.external)
1727                 md_super_wait(mddev);
1728         md_bitmap_update_sb(bitmap);
1729 }
1730
1731 /*
1732  * free memory that was allocated
1733  */
1734 void md_bitmap_free(struct bitmap *bitmap)
1735 {
1736         unsigned long k, pages;
1737         struct bitmap_page *bp;
1738
1739         if (!bitmap) /* there was no bitmap */
1740                 return;
1741
1742         if (bitmap->sysfs_can_clear)
1743                 sysfs_put(bitmap->sysfs_can_clear);
1744
1745         if (mddev_is_clustered(bitmap->mddev) && bitmap->mddev->cluster_info &&
1746                 bitmap->cluster_slot == md_cluster_ops->slot_number(bitmap->mddev))
1747                 md_cluster_stop(bitmap->mddev);
1748
1749         /* Shouldn't be needed - but just in case.... */
1750         wait_event(bitmap->write_wait,
1751                    atomic_read(&bitmap->pending_writes) == 0);
1752
1753         /* release the bitmap file  */
1754         md_bitmap_file_unmap(&bitmap->storage);
1755
1756         bp = bitmap->counts.bp;
1757         pages = bitmap->counts.pages;
1758
1759         /* free all allocated memory */
1760
1761         if (bp) /* deallocate the page memory */
1762                 for (k = 0; k < pages; k++)
1763                         if (bp[k].map && !bp[k].hijacked)
1764                                 kfree(bp[k].map);
1765         kfree(bp);
1766         kfree(bitmap);
1767 }
1768 EXPORT_SYMBOL(md_bitmap_free);
1769
1770 void md_bitmap_wait_behind_writes(struct mddev *mddev)
1771 {
1772         struct bitmap *bitmap = mddev->bitmap;
1773
1774         /* wait for behind writes to complete */
1775         if (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
1776                 pr_debug("md:%s: behind writes in progress - waiting to stop.\n",
1777                          mdname(mddev));
1778                 /* need to kick something here to make sure I/O goes? */
1779                 wait_event(bitmap->behind_wait,
1780                            atomic_read(&bitmap->behind_writes) == 0);
1781         }
1782 }
1783
1784 void md_bitmap_destroy(struct mddev *mddev)
1785 {
1786         struct bitmap *bitmap = mddev->bitmap;
1787
1788         if (!bitmap) /* there was no bitmap */
1789                 return;
1790
1791         md_bitmap_wait_behind_writes(mddev);
1792         if (!mddev->serialize_policy)
1793                 mddev_destroy_serial_pool(mddev, NULL, true);
1794
1795         mutex_lock(&mddev->bitmap_info.mutex);
1796         spin_lock(&mddev->lock);
1797         mddev->bitmap = NULL; /* disconnect from the md device */
1798         spin_unlock(&mddev->lock);
1799         mutex_unlock(&mddev->bitmap_info.mutex);
1800         if (mddev->thread)
1801                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1802
1803         md_bitmap_free(bitmap);
1804 }
1805
1806 /*
1807  * initialize the bitmap structure
1808  * if this returns an error, bitmap_destroy must be called to do clean up
1809  * once mddev->bitmap is set
1810  */
1811 struct bitmap *md_bitmap_create(struct mddev *mddev, int slot)
1812 {
1813         struct bitmap *bitmap;
1814         sector_t blocks = mddev->resync_max_sectors;
1815         struct file *file = mddev->bitmap_info.file;
1816         int err;
1817         struct kernfs_node *bm = NULL;
1818
1819         BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
1820
1821         BUG_ON(file && mddev->bitmap_info.offset);
1822
1823         if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
1824                 pr_notice("md/raid:%s: array with journal cannot have bitmap\n",
1825                           mdname(mddev));
1826                 return ERR_PTR(-EBUSY);
1827         }
1828
1829         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1830         if (!bitmap)
1831                 return ERR_PTR(-ENOMEM);
1832
1833         spin_lock_init(&bitmap->counts.lock);
1834         atomic_set(&bitmap->pending_writes, 0);
1835         init_waitqueue_head(&bitmap->write_wait);
1836         init_waitqueue_head(&bitmap->overflow_wait);
1837         init_waitqueue_head(&bitmap->behind_wait);
1838
1839         bitmap->mddev = mddev;
1840         bitmap->cluster_slot = slot;
1841
1842         if (mddev->kobj.sd)
1843                 bm = sysfs_get_dirent(mddev->kobj.sd, "bitmap");
1844         if (bm) {
1845                 bitmap->sysfs_can_clear = sysfs_get_dirent(bm, "can_clear");
1846                 sysfs_put(bm);
1847         } else
1848                 bitmap->sysfs_can_clear = NULL;
1849
1850         bitmap->storage.file = file;
1851         if (file) {
1852                 get_file(file);
1853                 /* As future accesses to this file will use bmap,
1854                  * and bypass the page cache, we must sync the file
1855                  * first.
1856                  */
1857                 vfs_fsync(file, 1);
1858         }
1859         /* read superblock from bitmap file (this sets mddev->bitmap_info.chunksize) */
1860         if (!mddev->bitmap_info.external) {
1861                 /*
1862                  * If 'MD_ARRAY_FIRST_USE' is set, then device-mapper is
1863                  * instructing us to create a new on-disk bitmap instance.
1864                  */
1865                 if (test_and_clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags))
1866                         err = md_bitmap_new_disk_sb(bitmap);
1867                 else
1868                         err = md_bitmap_read_sb(bitmap);
1869         } else {
1870                 err = 0;
1871                 if (mddev->bitmap_info.chunksize == 0 ||
1872                     mddev->bitmap_info.daemon_sleep == 0)
1873                         /* chunksize and time_base need to be
1874                          * set first. */
1875                         err = -EINVAL;
1876         }
1877         if (err)
1878                 goto error;
1879
1880         bitmap->daemon_lastrun = jiffies;
1881         err = md_bitmap_resize(bitmap, blocks, mddev->bitmap_info.chunksize, 1);
1882         if (err)
1883                 goto error;
1884
1885         pr_debug("created bitmap (%lu pages) for device %s\n",
1886                  bitmap->counts.pages, bmname(bitmap));
1887
1888         err = test_bit(BITMAP_WRITE_ERROR, &bitmap->flags) ? -EIO : 0;
1889         if (err)
1890                 goto error;
1891
1892         return bitmap;
1893  error:
1894         md_bitmap_free(bitmap);
1895         return ERR_PTR(err);
1896 }
1897
1898 int md_bitmap_load(struct mddev *mddev)
1899 {
1900         int err = 0;
1901         sector_t start = 0;
1902         sector_t sector = 0;
1903         struct bitmap *bitmap = mddev->bitmap;
1904         struct md_rdev *rdev;
1905
1906         if (!bitmap)
1907                 goto out;
1908
1909         rdev_for_each(rdev, mddev)
1910                 mddev_create_serial_pool(mddev, rdev, true);
1911
1912         if (mddev_is_clustered(mddev))
1913                 md_cluster_ops->load_bitmaps(mddev, mddev->bitmap_info.nodes);
1914
1915         /* Clear out old bitmap info first:  Either there is none, or we
1916          * are resuming after someone else has possibly changed things,
1917          * so we should forget old cached info.
1918          * All chunks should be clean, but some might need_sync.
1919          */
1920         while (sector < mddev->resync_max_sectors) {
1921                 sector_t blocks;
1922                 md_bitmap_start_sync(bitmap, sector, &blocks, 0);
1923                 sector += blocks;
1924         }
1925         md_bitmap_close_sync(bitmap);
1926
1927         if (mddev->degraded == 0
1928             || bitmap->events_cleared == mddev->events)
1929                 /* no need to keep dirty bits to optimise a
1930                  * re-add of a missing device */
1931                 start = mddev->recovery_cp;
1932
1933         mutex_lock(&mddev->bitmap_info.mutex);
1934         err = md_bitmap_init_from_disk(bitmap, start);
1935         mutex_unlock(&mddev->bitmap_info.mutex);
1936
1937         if (err)
1938                 goto out;
1939         clear_bit(BITMAP_STALE, &bitmap->flags);
1940
1941         /* Kick recovery in case any bits were set */
1942         set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
1943
1944         mddev->thread->timeout = mddev->bitmap_info.daemon_sleep;
1945         md_wakeup_thread(mddev->thread);
1946
1947         md_bitmap_update_sb(bitmap);
1948
1949         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
1950                 err = -EIO;
1951 out:
1952         return err;
1953 }
1954 EXPORT_SYMBOL_GPL(md_bitmap_load);
1955
1956 /* caller need to free returned bitmap with md_bitmap_free() */
1957 struct bitmap *get_bitmap_from_slot(struct mddev *mddev, int slot)
1958 {
1959         int rv = 0;
1960         struct bitmap *bitmap;
1961
1962         bitmap = md_bitmap_create(mddev, slot);
1963         if (IS_ERR(bitmap)) {
1964                 rv = PTR_ERR(bitmap);
1965                 return ERR_PTR(rv);
1966         }
1967
1968         rv = md_bitmap_init_from_disk(bitmap, 0);
1969         if (rv) {
1970                 md_bitmap_free(bitmap);
1971                 return ERR_PTR(rv);
1972         }
1973
1974         return bitmap;
1975 }
1976 EXPORT_SYMBOL(get_bitmap_from_slot);
1977
1978 /* Loads the bitmap associated with slot and copies the resync information
1979  * to our bitmap
1980  */
1981 int md_bitmap_copy_from_slot(struct mddev *mddev, int slot,
1982                 sector_t *low, sector_t *high, bool clear_bits)
1983 {
1984         int rv = 0, i, j;
1985         sector_t block, lo = 0, hi = 0;
1986         struct bitmap_counts *counts;
1987         struct bitmap *bitmap;
1988
1989         bitmap = get_bitmap_from_slot(mddev, slot);
1990         if (IS_ERR(bitmap)) {
1991                 pr_err("%s can't get bitmap from slot %d\n", __func__, slot);
1992                 return -1;
1993         }
1994
1995         counts = &bitmap->counts;
1996         for (j = 0; j < counts->chunks; j++) {
1997                 block = (sector_t)j << counts->chunkshift;
1998                 if (md_bitmap_file_test_bit(bitmap, block)) {
1999                         if (!lo)
2000                                 lo = block;
2001                         hi = block;
2002                         md_bitmap_file_clear_bit(bitmap, block);
2003                         md_bitmap_set_memory_bits(mddev->bitmap, block, 1);
2004                         md_bitmap_file_set_bit(mddev->bitmap, block);
2005                 }
2006         }
2007
2008         if (clear_bits) {
2009                 md_bitmap_update_sb(bitmap);
2010                 /* BITMAP_PAGE_PENDING is set, but bitmap_unplug needs
2011                  * BITMAP_PAGE_DIRTY or _NEEDWRITE to write ... */
2012                 for (i = 0; i < bitmap->storage.file_pages; i++)
2013                         if (test_page_attr(bitmap, i, BITMAP_PAGE_PENDING))
2014                                 set_page_attr(bitmap, i, BITMAP_PAGE_NEEDWRITE);
2015                 md_bitmap_unplug(bitmap);
2016         }
2017         md_bitmap_unplug(mddev->bitmap);
2018         *low = lo;
2019         *high = hi;
2020         md_bitmap_free(bitmap);
2021
2022         return rv;
2023 }
2024 EXPORT_SYMBOL_GPL(md_bitmap_copy_from_slot);
2025
2026
2027 void md_bitmap_status(struct seq_file *seq, struct bitmap *bitmap)
2028 {
2029         unsigned long chunk_kb;
2030         struct bitmap_counts *counts;
2031
2032         if (!bitmap)
2033                 return;
2034
2035         counts = &bitmap->counts;
2036
2037         chunk_kb = bitmap->mddev->bitmap_info.chunksize >> 10;
2038         seq_printf(seq, "bitmap: %lu/%lu pages [%luKB], "
2039                    "%lu%s chunk",
2040                    counts->pages - counts->missing_pages,
2041                    counts->pages,
2042                    (counts->pages - counts->missing_pages)
2043                    << (PAGE_SHIFT - 10),
2044                    chunk_kb ? chunk_kb : bitmap->mddev->bitmap_info.chunksize,
2045                    chunk_kb ? "KB" : "B");
2046         if (bitmap->storage.file) {
2047                 seq_printf(seq, ", file: ");
2048                 seq_file_path(seq, bitmap->storage.file, " \t\n");
2049         }
2050
2051         seq_printf(seq, "\n");
2052 }
2053
2054 int md_bitmap_resize(struct bitmap *bitmap, sector_t blocks,
2055                   int chunksize, int init)
2056 {
2057         /* If chunk_size is 0, choose an appropriate chunk size.
2058          * Then possibly allocate new storage space.
2059          * Then quiesce, copy bits, replace bitmap, and re-start
2060          *
2061          * This function is called both to set up the initial bitmap
2062          * and to resize the bitmap while the array is active.
2063          * If this happens as a result of the array being resized,
2064          * chunksize will be zero, and we need to choose a suitable
2065          * chunksize, otherwise we use what we are given.
2066          */
2067         struct bitmap_storage store;
2068         struct bitmap_counts old_counts;
2069         unsigned long chunks;
2070         sector_t block;
2071         sector_t old_blocks, new_blocks;
2072         int chunkshift;
2073         int ret = 0;
2074         long pages;
2075         struct bitmap_page *new_bp;
2076
2077         if (bitmap->storage.file && !init) {
2078                 pr_info("md: cannot resize file-based bitmap\n");
2079                 return -EINVAL;
2080         }
2081
2082         if (chunksize == 0) {
2083                 /* If there is enough space, leave the chunk size unchanged,
2084                  * else increase by factor of two until there is enough space.
2085                  */
2086                 long bytes;
2087                 long space = bitmap->mddev->bitmap_info.space;
2088
2089                 if (space == 0) {
2090                         /* We don't know how much space there is, so limit
2091                          * to current size - in sectors.
2092                          */
2093                         bytes = DIV_ROUND_UP(bitmap->counts.chunks, 8);
2094                         if (!bitmap->mddev->bitmap_info.external)
2095                                 bytes += sizeof(bitmap_super_t);
2096                         space = DIV_ROUND_UP(bytes, 512);
2097                         bitmap->mddev->bitmap_info.space = space;
2098                 }
2099                 chunkshift = bitmap->counts.chunkshift;
2100                 chunkshift--;
2101                 do {
2102                         /* 'chunkshift' is shift from block size to chunk size */
2103                         chunkshift++;
2104                         chunks = DIV_ROUND_UP_SECTOR_T(blocks, 1 << chunkshift);
2105                         bytes = DIV_ROUND_UP(chunks, 8);
2106                         if (!bitmap->mddev->bitmap_info.external)
2107                                 bytes += sizeof(bitmap_super_t);
2108                 } while (bytes > (space << 9) && (chunkshift + BITMAP_BLOCK_SHIFT) <
2109                         (BITS_PER_BYTE * sizeof(((bitmap_super_t *)0)->chunksize) - 1));
2110         } else
2111                 chunkshift = ffz(~chunksize) - BITMAP_BLOCK_SHIFT;
2112
2113         chunks = DIV_ROUND_UP_SECTOR_T(blocks, 1 << chunkshift);
2114         memset(&store, 0, sizeof(store));
2115         if (bitmap->mddev->bitmap_info.offset || bitmap->mddev->bitmap_info.file)
2116                 ret = md_bitmap_storage_alloc(&store, chunks,
2117                                               !bitmap->mddev->bitmap_info.external,
2118                                               mddev_is_clustered(bitmap->mddev)
2119                                               ? bitmap->cluster_slot : 0);
2120         if (ret) {
2121                 md_bitmap_file_unmap(&store);
2122                 goto err;
2123         }
2124
2125         pages = DIV_ROUND_UP(chunks, PAGE_COUNTER_RATIO);
2126
2127         new_bp = kcalloc(pages, sizeof(*new_bp), GFP_KERNEL);
2128         ret = -ENOMEM;
2129         if (!new_bp) {
2130                 md_bitmap_file_unmap(&store);
2131                 goto err;
2132         }
2133
2134         if (!init)
2135                 bitmap->mddev->pers->quiesce(bitmap->mddev, 1);
2136
2137         store.file = bitmap->storage.file;
2138         bitmap->storage.file = NULL;
2139
2140         if (store.sb_page && bitmap->storage.sb_page)
2141                 memcpy(page_address(store.sb_page),
2142                        page_address(bitmap->storage.sb_page),
2143                        sizeof(bitmap_super_t));
2144         spin_lock_irq(&bitmap->counts.lock);
2145         md_bitmap_file_unmap(&bitmap->storage);
2146         bitmap->storage = store;
2147
2148         old_counts = bitmap->counts;
2149         bitmap->counts.bp = new_bp;
2150         bitmap->counts.pages = pages;
2151         bitmap->counts.missing_pages = pages;
2152         bitmap->counts.chunkshift = chunkshift;
2153         bitmap->counts.chunks = chunks;
2154         bitmap->mddev->bitmap_info.chunksize = 1UL << (chunkshift +
2155                                                      BITMAP_BLOCK_SHIFT);
2156
2157         blocks = min(old_counts.chunks << old_counts.chunkshift,
2158                      chunks << chunkshift);
2159
2160         /* For cluster raid, need to pre-allocate bitmap */
2161         if (mddev_is_clustered(bitmap->mddev)) {
2162                 unsigned long page;
2163                 for (page = 0; page < pages; page++) {
2164                         ret = md_bitmap_checkpage(&bitmap->counts, page, 1, 1);
2165                         if (ret) {
2166                                 unsigned long k;
2167
2168                                 /* deallocate the page memory */
2169                                 for (k = 0; k < page; k++) {
2170                                         kfree(new_bp[k].map);
2171                                 }
2172                                 kfree(new_bp);
2173
2174                                 /* restore some fields from old_counts */
2175                                 bitmap->counts.bp = old_counts.bp;
2176                                 bitmap->counts.pages = old_counts.pages;
2177                                 bitmap->counts.missing_pages = old_counts.pages;
2178                                 bitmap->counts.chunkshift = old_counts.chunkshift;
2179                                 bitmap->counts.chunks = old_counts.chunks;
2180                                 bitmap->mddev->bitmap_info.chunksize =
2181                                         1UL << (old_counts.chunkshift + BITMAP_BLOCK_SHIFT);
2182                                 blocks = old_counts.chunks << old_counts.chunkshift;
2183                                 pr_warn("Could not pre-allocate in-memory bitmap for cluster raid\n");
2184                                 break;
2185                         } else
2186                                 bitmap->counts.bp[page].count += 1;
2187                 }
2188         }
2189
2190         for (block = 0; block < blocks; ) {
2191                 bitmap_counter_t *bmc_old, *bmc_new;
2192                 int set;
2193
2194                 bmc_old = md_bitmap_get_counter(&old_counts, block, &old_blocks, 0);
2195                 set = bmc_old && NEEDED(*bmc_old);
2196
2197                 if (set) {
2198                         bmc_new = md_bitmap_get_counter(&bitmap->counts, block, &new_blocks, 1);
2199                         if (bmc_new) {
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
2205                                         start <<= chunkshift;
2206                                         while (start < end) {
2207                                                 md_bitmap_file_set_bit(bitmap, block);
2208                                                 start += 1 << chunkshift;
2209                                         }
2210                                         *bmc_new = 2;
2211                                         md_bitmap_count_page(&bitmap->counts, block, 1);
2212                                         md_bitmap_set_pending(&bitmap->counts, block);
2213                                 }
2214                                 *bmc_new |= NEEDED_MASK;
2215                         }
2216                         if (new_blocks < old_blocks)
2217                                 old_blocks = new_blocks;
2218                 }
2219                 block += old_blocks;
2220         }
2221
2222         if (bitmap->counts.bp != old_counts.bp) {
2223                 unsigned long k;
2224                 for (k = 0; k < old_counts.pages; k++)
2225                         if (!old_counts.bp[k].hijacked)
2226                                 kfree(old_counts.bp[k].map);
2227                 kfree(old_counts.bp);
2228         }
2229
2230         if (!init) {
2231                 int i;
2232                 while (block < (chunks << chunkshift)) {
2233                         bitmap_counter_t *bmc;
2234                         bmc = md_bitmap_get_counter(&bitmap->counts, block, &new_blocks, 1);
2235                         if (bmc) {
2236                                 /* new space.  It needs to be resynced, so
2237                                  * we set NEEDED_MASK.
2238                                  */
2239                                 if (*bmc == 0) {
2240                                         *bmc = NEEDED_MASK | 2;
2241                                         md_bitmap_count_page(&bitmap->counts, block, 1);
2242                                         md_bitmap_set_pending(&bitmap->counts, block);
2243                                 }
2244                         }
2245                         block += new_blocks;
2246                 }
2247                 for (i = 0; i < bitmap->storage.file_pages; i++)
2248                         set_page_attr(bitmap, i, BITMAP_PAGE_DIRTY);
2249         }
2250         spin_unlock_irq(&bitmap->counts.lock);
2251
2252         if (!init) {
2253                 md_bitmap_unplug(bitmap);
2254                 bitmap->mddev->pers->quiesce(bitmap->mddev, 0);
2255         }
2256         ret = 0;
2257 err:
2258         return ret;
2259 }
2260 EXPORT_SYMBOL_GPL(md_bitmap_resize);
2261
2262 static ssize_t
2263 location_show(struct mddev *mddev, char *page)
2264 {
2265         ssize_t len;
2266         if (mddev->bitmap_info.file)
2267                 len = sprintf(page, "file");
2268         else if (mddev->bitmap_info.offset)
2269                 len = sprintf(page, "%+lld", (long long)mddev->bitmap_info.offset);
2270         else
2271                 len = sprintf(page, "none");
2272         len += sprintf(page+len, "\n");
2273         return len;
2274 }
2275
2276 static ssize_t
2277 location_store(struct mddev *mddev, const char *buf, size_t len)
2278 {
2279         int rv;
2280
2281         rv = mddev_lock(mddev);
2282         if (rv)
2283                 return rv;
2284         if (mddev->pers) {
2285                 if (!mddev->pers->quiesce) {
2286                         rv = -EBUSY;
2287                         goto out;
2288                 }
2289                 if (mddev->recovery || mddev->sync_thread) {
2290                         rv = -EBUSY;
2291                         goto out;
2292                 }
2293         }
2294
2295         if (mddev->bitmap || mddev->bitmap_info.file ||
2296             mddev->bitmap_info.offset) {
2297                 /* bitmap already configured.  Only option is to clear it */
2298                 if (strncmp(buf, "none", 4) != 0) {
2299                         rv = -EBUSY;
2300                         goto out;
2301                 }
2302                 if (mddev->pers) {
2303                         mddev_suspend(mddev);
2304                         md_bitmap_destroy(mddev);
2305                         mddev_resume(mddev);
2306                 }
2307                 mddev->bitmap_info.offset = 0;
2308                 if (mddev->bitmap_info.file) {
2309                         struct file *f = mddev->bitmap_info.file;
2310                         mddev->bitmap_info.file = NULL;
2311                         fput(f);
2312                 }
2313         } else {
2314                 /* No bitmap, OK to set a location */
2315                 long long offset;
2316                 if (strncmp(buf, "none", 4) == 0)
2317                         /* nothing to be done */;
2318                 else if (strncmp(buf, "file:", 5) == 0) {
2319                         /* Not supported yet */
2320                         rv = -EINVAL;
2321                         goto out;
2322                 } else {
2323                         if (buf[0] == '+')
2324                                 rv = kstrtoll(buf+1, 10, &offset);
2325                         else
2326                                 rv = kstrtoll(buf, 10, &offset);
2327                         if (rv)
2328                                 goto out;
2329                         if (offset == 0) {
2330                                 rv = -EINVAL;
2331                                 goto out;
2332                         }
2333                         if (mddev->bitmap_info.external == 0 &&
2334                             mddev->major_version == 0 &&
2335                             offset != mddev->bitmap_info.default_offset) {
2336                                 rv = -EINVAL;
2337                                 goto out;
2338                         }
2339                         mddev->bitmap_info.offset = offset;
2340                         if (mddev->pers) {
2341                                 struct bitmap *bitmap;
2342                                 bitmap = md_bitmap_create(mddev, -1);
2343                                 mddev_suspend(mddev);
2344                                 if (IS_ERR(bitmap))
2345                                         rv = PTR_ERR(bitmap);
2346                                 else {
2347                                         mddev->bitmap = bitmap;
2348                                         rv = md_bitmap_load(mddev);
2349                                         if (rv)
2350                                                 mddev->bitmap_info.offset = 0;
2351                                 }
2352                                 if (rv) {
2353                                         md_bitmap_destroy(mddev);
2354                                         mddev_resume(mddev);
2355                                         goto out;
2356                                 }
2357                                 mddev_resume(mddev);
2358                         }
2359                 }
2360         }
2361         if (!mddev->external) {
2362                 /* Ensure new bitmap info is stored in
2363                  * metadata promptly.
2364                  */
2365                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
2366                 md_wakeup_thread(mddev->thread);
2367         }
2368         rv = 0;
2369 out:
2370         mddev_unlock(mddev);
2371         if (rv)
2372                 return rv;
2373         return len;
2374 }
2375
2376 static struct md_sysfs_entry bitmap_location =
2377 __ATTR(location, S_IRUGO|S_IWUSR, location_show, location_store);
2378
2379 /* 'bitmap/space' is the space available at 'location' for the
2380  * bitmap.  This allows the kernel to know when it is safe to
2381  * resize the bitmap to match a resized array.
2382  */
2383 static ssize_t
2384 space_show(struct mddev *mddev, char *page)
2385 {
2386         return sprintf(page, "%lu\n", mddev->bitmap_info.space);
2387 }
2388
2389 static ssize_t
2390 space_store(struct mddev *mddev, const char *buf, size_t len)
2391 {
2392         unsigned long sectors;
2393         int rv;
2394
2395         rv = kstrtoul(buf, 10, &sectors);
2396         if (rv)
2397                 return rv;
2398
2399         if (sectors == 0)
2400                 return -EINVAL;
2401
2402         if (mddev->bitmap &&
2403             sectors < (mddev->bitmap->storage.bytes + 511) >> 9)
2404                 return -EFBIG; /* Bitmap is too big for this small space */
2405
2406         /* could make sure it isn't too big, but that isn't really
2407          * needed - user-space should be careful.
2408          */
2409         mddev->bitmap_info.space = sectors;
2410         return len;
2411 }
2412
2413 static struct md_sysfs_entry bitmap_space =
2414 __ATTR(space, S_IRUGO|S_IWUSR, space_show, space_store);
2415
2416 static ssize_t
2417 timeout_show(struct mddev *mddev, char *page)
2418 {
2419         ssize_t len;
2420         unsigned long secs = mddev->bitmap_info.daemon_sleep / HZ;
2421         unsigned long jifs = mddev->bitmap_info.daemon_sleep % HZ;
2422
2423         len = sprintf(page, "%lu", secs);
2424         if (jifs)
2425                 len += sprintf(page+len, ".%03u", jiffies_to_msecs(jifs));
2426         len += sprintf(page+len, "\n");
2427         return len;
2428 }
2429
2430 static ssize_t
2431 timeout_store(struct mddev *mddev, const char *buf, size_t len)
2432 {
2433         /* timeout can be set at any time */
2434         unsigned long timeout;
2435         int rv = strict_strtoul_scaled(buf, &timeout, 4);
2436         if (rv)
2437                 return rv;
2438
2439         /* just to make sure we don't overflow... */
2440         if (timeout >= LONG_MAX / HZ)
2441                 return -EINVAL;
2442
2443         timeout = timeout * HZ / 10000;
2444
2445         if (timeout >= MAX_SCHEDULE_TIMEOUT)
2446                 timeout = MAX_SCHEDULE_TIMEOUT-1;
2447         if (timeout < 1)
2448                 timeout = 1;
2449         mddev->bitmap_info.daemon_sleep = timeout;
2450         if (mddev->thread) {
2451                 /* if thread->timeout is MAX_SCHEDULE_TIMEOUT, then
2452                  * the bitmap is all clean and we don't need to
2453                  * adjust the timeout right now
2454                  */
2455                 if (mddev->thread->timeout < MAX_SCHEDULE_TIMEOUT) {
2456                         mddev->thread->timeout = timeout;
2457                         md_wakeup_thread(mddev->thread);
2458                 }
2459         }
2460         return len;
2461 }
2462
2463 static struct md_sysfs_entry bitmap_timeout =
2464 __ATTR(time_base, S_IRUGO|S_IWUSR, timeout_show, timeout_store);
2465
2466 static ssize_t
2467 backlog_show(struct mddev *mddev, char *page)
2468 {
2469         return sprintf(page, "%lu\n", mddev->bitmap_info.max_write_behind);
2470 }
2471
2472 static ssize_t
2473 backlog_store(struct mddev *mddev, const char *buf, size_t len)
2474 {
2475         unsigned long backlog;
2476         unsigned long old_mwb = mddev->bitmap_info.max_write_behind;
2477         struct md_rdev *rdev;
2478         bool has_write_mostly = false;
2479         int rv = kstrtoul(buf, 10, &backlog);
2480         if (rv)
2481                 return rv;
2482         if (backlog > COUNTER_MAX)
2483                 return -EINVAL;
2484
2485         /*
2486          * Without write mostly device, it doesn't make sense to set
2487          * backlog for max_write_behind.
2488          */
2489         rdev_for_each(rdev, mddev) {
2490                 if (test_bit(WriteMostly, &rdev->flags)) {
2491                         has_write_mostly = true;
2492                         break;
2493                 }
2494         }
2495         if (!has_write_mostly) {
2496                 pr_warn_ratelimited("%s: can't set backlog, no write mostly device available\n",
2497                                     mdname(mddev));
2498                 return -EINVAL;
2499         }
2500
2501         mddev->bitmap_info.max_write_behind = backlog;
2502         if (!backlog && mddev->serial_info_pool) {
2503                 /* serial_info_pool is not needed if backlog is zero */
2504                 if (!mddev->serialize_policy)
2505                         mddev_destroy_serial_pool(mddev, NULL, false);
2506         } else if (backlog && !mddev->serial_info_pool) {
2507                 /* serial_info_pool is needed since backlog is not zero */
2508                 struct md_rdev *rdev;
2509
2510                 rdev_for_each(rdev, mddev)
2511                         mddev_create_serial_pool(mddev, rdev, false);
2512         }
2513         if (old_mwb != backlog)
2514                 md_bitmap_update_sb(mddev->bitmap);
2515         return len;
2516 }
2517
2518 static struct md_sysfs_entry bitmap_backlog =
2519 __ATTR(backlog, S_IRUGO|S_IWUSR, backlog_show, backlog_store);
2520
2521 static ssize_t
2522 chunksize_show(struct mddev *mddev, char *page)
2523 {
2524         return sprintf(page, "%lu\n", mddev->bitmap_info.chunksize);
2525 }
2526
2527 static ssize_t
2528 chunksize_store(struct mddev *mddev, const char *buf, size_t len)
2529 {
2530         /* Can only be changed when no bitmap is active */
2531         int rv;
2532         unsigned long csize;
2533         if (mddev->bitmap)
2534                 return -EBUSY;
2535         rv = kstrtoul(buf, 10, &csize);
2536         if (rv)
2537                 return rv;
2538         if (csize < 512 ||
2539             !is_power_of_2(csize))
2540                 return -EINVAL;
2541         if (BITS_PER_LONG > 32 && csize >= (1ULL << (BITS_PER_BYTE *
2542                 sizeof(((bitmap_super_t *)0)->chunksize))))
2543                 return -EOVERFLOW;
2544         mddev->bitmap_info.chunksize = csize;
2545         return len;
2546 }
2547
2548 static struct md_sysfs_entry bitmap_chunksize =
2549 __ATTR(chunksize, S_IRUGO|S_IWUSR, chunksize_show, chunksize_store);
2550
2551 static ssize_t metadata_show(struct mddev *mddev, char *page)
2552 {
2553         if (mddev_is_clustered(mddev))
2554                 return sprintf(page, "clustered\n");
2555         return sprintf(page, "%s\n", (mddev->bitmap_info.external
2556                                       ? "external" : "internal"));
2557 }
2558
2559 static ssize_t metadata_store(struct mddev *mddev, const char *buf, size_t len)
2560 {
2561         if (mddev->bitmap ||
2562             mddev->bitmap_info.file ||
2563             mddev->bitmap_info.offset)
2564                 return -EBUSY;
2565         if (strncmp(buf, "external", 8) == 0)
2566                 mddev->bitmap_info.external = 1;
2567         else if ((strncmp(buf, "internal", 8) == 0) ||
2568                         (strncmp(buf, "clustered", 9) == 0))
2569                 mddev->bitmap_info.external = 0;
2570         else
2571                 return -EINVAL;
2572         return len;
2573 }
2574
2575 static struct md_sysfs_entry bitmap_metadata =
2576 __ATTR(metadata, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
2577
2578 static ssize_t can_clear_show(struct mddev *mddev, char *page)
2579 {
2580         int len;
2581         spin_lock(&mddev->lock);
2582         if (mddev->bitmap)
2583                 len = sprintf(page, "%s\n", (mddev->bitmap->need_sync ?
2584                                              "false" : "true"));
2585         else
2586                 len = sprintf(page, "\n");
2587         spin_unlock(&mddev->lock);
2588         return len;
2589 }
2590
2591 static ssize_t can_clear_store(struct mddev *mddev, const char *buf, size_t len)
2592 {
2593         if (mddev->bitmap == NULL)
2594                 return -ENOENT;
2595         if (strncmp(buf, "false", 5) == 0)
2596                 mddev->bitmap->need_sync = 1;
2597         else if (strncmp(buf, "true", 4) == 0) {
2598                 if (mddev->degraded)
2599                         return -EBUSY;
2600                 mddev->bitmap->need_sync = 0;
2601         } else
2602                 return -EINVAL;
2603         return len;
2604 }
2605
2606 static struct md_sysfs_entry bitmap_can_clear =
2607 __ATTR(can_clear, S_IRUGO|S_IWUSR, can_clear_show, can_clear_store);
2608
2609 static ssize_t
2610 behind_writes_used_show(struct mddev *mddev, char *page)
2611 {
2612         ssize_t ret;
2613         spin_lock(&mddev->lock);
2614         if (mddev->bitmap == NULL)
2615                 ret = sprintf(page, "0\n");
2616         else
2617                 ret = sprintf(page, "%lu\n",
2618                               mddev->bitmap->behind_writes_used);
2619         spin_unlock(&mddev->lock);
2620         return ret;
2621 }
2622
2623 static ssize_t
2624 behind_writes_used_reset(struct mddev *mddev, const char *buf, size_t len)
2625 {
2626         if (mddev->bitmap)
2627                 mddev->bitmap->behind_writes_used = 0;
2628         return len;
2629 }
2630
2631 static struct md_sysfs_entry max_backlog_used =
2632 __ATTR(max_backlog_used, S_IRUGO | S_IWUSR,
2633        behind_writes_used_show, behind_writes_used_reset);
2634
2635 static struct attribute *md_bitmap_attrs[] = {
2636         &bitmap_location.attr,
2637         &bitmap_space.attr,
2638         &bitmap_timeout.attr,
2639         &bitmap_backlog.attr,
2640         &bitmap_chunksize.attr,
2641         &bitmap_metadata.attr,
2642         &bitmap_can_clear.attr,
2643         &max_backlog_used.attr,
2644         NULL
2645 };
2646 const struct attribute_group md_bitmap_group = {
2647         .name = "bitmap",
2648         .attrs = md_bitmap_attrs,
2649 };