drivers/md/md-bitmap.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * bitmap.c two-level bitmap (C) Peter T. Breuer (ptb@ot.uc3m.es) 2003
   4  *
   5  * bitmap_create  - sets up the bitmap structure
   6  * bitmap_destroy - destroys the bitmap structure
   7  *
   8  * additions, Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.:
   9  * - added disk storage for bitmap
  10  * - changes to allow various bitmap chunk sizes
  11  */
  12
  13 /*
  14  * Still to do:
  15  *
  16  * flush after percent set rather than just time based. (maybe both).
  17  */
  18
  19 #include <linux/blkdev.h>
  20 #include <linux/module.h>
  21 #include <linux/errno.h>
  22 #include <linux/slab.h>
  23 #include <linux/init.h>
  24 #include <linux/timer.h>
  25 #include <linux/sched.h>
  26 #include <linux/list.h>
  27 #include <linux/file.h>
  28 #include <linux/mount.h>
  29 #include <linux/buffer_head.h>
  30 #include <linux/seq_file.h>
  31 #include <trace/events/block.h>
  32 #include "md.h"
  33 #include "md-bitmap.h"
  34
  35 static inline char *bmname(struct bitmap *bitmap)
  36 {
  37         return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
  38 }
  39
  40 /*
  41  * check a page and, if necessary, allocate it (or hijack it if the alloc fails)
  42  *
  43  * 1) check to see if this page is allocated, if it's not then try to alloc
  44  * 2) if the alloc fails, set the page's hijacked flag so we'll use the
  45  *    page pointer directly as a counter
  46  *
  47  * if we find our page, we increment the page's refcount so that it stays
  48  * allocated while we're using it
  49  */
  50 static int md_bitmap_checkpage(struct bitmap_counts *bitmap,
  51                                unsigned long page, int create, int no_hijack)
  52 __releases(bitmap->lock)
  53 __acquires(bitmap->lock)
  54 {
  55         unsigned char *mappage;
  56
  57         if (page >= bitmap->pages) {
  58                 /* This can happen if bitmap_start_sync goes beyond
  59                  * End-of-device while looking for a whole page.
  60                  * It is harmless.
  61                  */
  62                 return -EINVAL;
  63         }
  64
  65         if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
  66                 return 0;
  67
  68         if (bitmap->bp[page].map) /* page is already allocated, just return */
  69                 return 0;
  70
  71         if (!create)
  72                 return -ENOENT;
  73
  74         /* this page has not been allocated yet */
  75
  76         spin_unlock_irq(&bitmap->lock);
  77         /* It is possible that this is being called inside a
  78          * prepare_to_wait/finish_wait loop from raid5c:make_request().
  79          * In general it is not permitted to sleep in that context as it
  80          * can cause the loop to spin freely.
  81          * That doesn't apply here as we can only reach this point
  82          * once with any loop.
  83          * When this function completes, either bp[page].map or
  84          * bp[page].hijacked.  In either case, this function will
  85          * abort before getting to this point again.  So there is
  86          * no risk of a free-spin, and so it is safe to assert
  87          * that sleeping here is allowed.
  88          */
  89         sched_annotate_sleep();
  90         mappage = kzalloc(PAGE_SIZE, GFP_NOIO);
  91         spin_lock_irq(&bitmap->lock);
  92
  93         if (mappage == NULL) {
  94                 pr_debug("md/bitmap: map page allocation failed, hijacking\n");
  95                 /* We don't support hijack for cluster raid */
  96                 if (no_hijack)
  97                         return -ENOMEM;
  98                 /* failed - set the hijacked flag so that we can use the
  99                  * pointer as a counter */
 100                 if (!bitmap->bp[page].map)
 101                         bitmap->bp[page].hijacked = 1;
 102         } else if (bitmap->bp[page].map ||
 103                    bitmap->bp[page].hijacked) {
 104                 /* somebody beat us to getting the page */
 105                 kfree(mappage);
 106         } else {
 107
 108                 /* no page was in place and we have one, so install it */
 109
 110                 bitmap->bp[page].map = mappage;
 111                 bitmap->missing_pages--;
 112         }
 113         return 0;
 114 }
 115
 116 /* if page is completely empty, put it back on the free list, or dealloc it */
 117 /* if page was hijacked, unmark the flag so it might get alloced next time */
 118 /* Note: lock should be held when calling this */
 119 static void md_bitmap_checkfree(struct bitmap_counts *bitmap, unsigned long page)
 120 {
 121         char *ptr;
 122
 123         if (bitmap->bp[page].count) /* page is still busy */
 124                 return;
 125
 126         /* page is no longer in use, it can be released */
 127
 128         if (bitmap->bp[page].hijacked) { /* page was hijacked, undo this now */
 129                 bitmap->bp[page].hijacked = 0;
 130                 bitmap->bp[page].map = NULL;
 131         } else {
 132                 /* normal case, free the page */
 133                 ptr = bitmap->bp[page].map;
 134                 bitmap->bp[page].map = NULL;
 135                 bitmap->missing_pages++;
 136                 kfree(ptr);
 137         }
 138 }
 139
 140 /*
 141  * bitmap file handling - read and write the bitmap file and its superblock
 142  */
 143
 144 /*
 145  * basic page I/O operations
 146  */
 147
 148 /* IO operations when bitmap is stored near all superblocks */
 149 static int read_sb_page(struct mddev *mddev, loff_t offset,
 150                         struct page *page,
 151                         unsigned long index, int size)
 152 {
 153         /* choose a good rdev and read the page from there */
 154
 155         struct md_rdev *rdev;
 156         sector_t target;
 157
 158         rdev_for_each(rdev, mddev) {
 159                 if (! test_bit(In_sync, &rdev->flags)
 160                     || test_bit(Faulty, &rdev->flags)
 161                     || test_bit(Bitmap_sync, &rdev->flags))
 162                         continue;
 163
 164                 target = offset + index * (PAGE_SIZE/512);
 165
 166                 if (sync_page_io(rdev, target,
 167                                  roundup(size, bdev_logical_block_size(rdev->bdev)),
 168                                  page, REQ_OP_READ, 0, true)) {
 169                         page->index = index;
 170                         return 0;
 171                 }
 172         }
 173         return -EIO;
 174 }
 175
 176 static struct md_rdev *next_active_rdev(struct md_rdev *rdev, struct mddev *mddev)
 177 {
 178         /* Iterate the disks of an mddev, using rcu to protect access to the
 179          * linked list, and raising the refcount of devices we return to ensure
 180          * they don't disappear while in use.
 181          * As devices are only added or removed when raid_disk is < 0 and
 182          * nr_pending is 0 and In_sync is clear, the entries we return will
 183          * still be in the same position on the list when we re-enter
 184          * list_for_each_entry_continue_rcu.
 185          *
 186          * Note that if entered with 'rdev == NULL' to start at the
 187          * beginning, we temporarily assign 'rdev' to an address which
 188          * isn't really an rdev, but which can be used by
 189          * list_for_each_entry_continue_rcu() to find the first entry.
 190          */
 191         rcu_read_lock();
 192         if (rdev == NULL)
 193                 /* start at the beginning */
 194                 rdev = list_entry(&mddev->disks, struct md_rdev, same_set);
 195         else {
 196                 /* release the previous rdev and start from there. */
 197                 rdev_dec_pending(rdev, mddev);
 198         }
 199         list_for_each_entry_continue_rcu(rdev, &mddev->disks, same_set) {
 200                 if (rdev->raid_disk >= 0 &&
 201                     !test_bit(Faulty, &rdev->flags)) {
 202                         /* this is a usable devices */
 203                         atomic_inc(&rdev->nr_pending);
 204                         rcu_read_unlock();
 205                         return rdev;
 206                 }
 207         }
 208         rcu_read_unlock();
 209         return NULL;
 210 }
 211
 212 static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
 213 {
 214         struct md_rdev *rdev;
 215         struct block_device *bdev;
 216         struct mddev *mddev = bitmap->mddev;
 217         struct bitmap_storage *store = &bitmap->storage;
 218
 219 restart:
 220         rdev = NULL;
 221         while ((rdev = next_active_rdev(rdev, mddev)) != NULL) {
 222                 int size = PAGE_SIZE;
 223                 loff_t offset = mddev->bitmap_info.offset;
 224
 225                 bdev = (rdev->meta_bdev) ? rdev->meta_bdev : rdev->bdev;
 226
 227                 if (page->index == store->file_pages-1) {
 228                         int last_page_size = store->bytes & (PAGE_SIZE-1);
 229                         if (last_page_size == 0)
 230                                 last_page_size = PAGE_SIZE;
 231                         size = roundup(last_page_size,
 232                                        bdev_logical_block_size(bdev));
 233                 }
 234                 /* Just make sure we aren't corrupting data or
 235                  * metadata
 236                  */
 237                 if (mddev->external) {
 238                         /* Bitmap could be anywhere. */
 239                         if (rdev->sb_start + offset + (page->index
 240                                                        * (PAGE_SIZE/512))
 241                             > rdev->data_offset
 242                             &&
 243                             rdev->sb_start + offset
 244                             < (rdev->data_offset + mddev->dev_sectors
 245                              + (PAGE_SIZE/512)))
 246                                 goto bad_alignment;
 247                 } else if (offset < 0) {
 248                         /* DATA  BITMAP METADATA  */
 249                         if (offset
 250                             + (long)(page->index * (PAGE_SIZE/512))
 251                             + size/512 > 0)
 252                                 /* bitmap runs in to metadata */
 253                                 goto bad_alignment;
 254                         if (rdev->data_offset + mddev->dev_sectors
 255                             > rdev->sb_start + offset)
 256                                 /* data runs in to bitmap */
 257                                 goto bad_alignment;
 258                 } else if (rdev->sb_start < rdev->data_offset) {
 259                         /* METADATA BITMAP DATA */
 260                         if (rdev->sb_start
 261                             + offset
 262                             + page->index*(PAGE_SIZE/512) + size/512
 263                             > rdev->data_offset)
 264                                 /* bitmap runs in to data */
 265                                 goto bad_alignment;
 266                 } else {
 267                         /* DATA METADATA BITMAP - no problems */
 268                 }
 269                 md_super_write(mddev, rdev,
 270                                rdev->sb_start + offset
 271                                + page->index * (PAGE_SIZE/512),
 272                                size,
 273                                page);
 274         }
 275
 276         if (wait && md_super_wait(mddev) < 0)
 277                 goto restart;
 278         return 0;
 279
 280  bad_alignment:
 281         return -EINVAL;
 282 }
 283
 284 static void md_bitmap_file_kick(struct bitmap *bitmap);
 285 /*
 286  * write out a page to a file
 287  */
 288 static void write_page(struct bitmap *bitmap, struct page *page, int wait)
 289 {
 290         struct buffer_head *bh;
 291
 292         if (bitmap->storage.file == NULL) {
 293                 switch (write_sb_page(bitmap, page, wait)) {
 294                 case -EINVAL:
 295                         set_bit(BITMAP_WRITE_ERROR, &bitmap->flags);
 296                 }
 297         } else {
 298
 299                 bh = page_buffers(page);
 300
 301                 while (bh && bh->b_blocknr) {
 302                         atomic_inc(&bitmap->pending_writes);
 303                         set_buffer_locked(bh);
 304                         set_buffer_mapped(bh);
 305                         submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
 306                         bh = bh->b_this_page;
 307                 }
 308
 309                 if (wait)
 310                         wait_event(bitmap->write_wait,
 311                                    atomic_read(&bitmap->pending_writes)==0);
 312         }
 313         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
 314                 md_bitmap_file_kick(bitmap);
 315 }
 316
 317 static void end_bitmap_write(struct buffer_head *bh, int uptodate)
 318 {
 319         struct bitmap *bitmap = bh->b_private;
 320
 321         if (!uptodate)
 322                 set_bit(BITMAP_WRITE_ERROR, &bitmap->flags);
 323         if (atomic_dec_and_test(&bitmap->pending_writes))
 324                 wake_up(&bitmap->write_wait);
 325 }
 326
 327 /* copied from buffer.c */
 328 static void
 329 __clear_page_buffers(struct page *page)
 330 {
 331         ClearPagePrivate(page);
 332         set_page_private(page, 0);
 333         put_page(page);
 334 }
 335 static void free_buffers(struct page *page)
 336 {
 337         struct buffer_head *bh;
 338
 339         if (!PagePrivate(page))
 340                 return;
 341
 342         bh = page_buffers(page);
 343         while (bh) {
 344                 struct buffer_head *next = bh->b_this_page;
 345                 free_buffer_head(bh);
 346                 bh = next;
 347         }
 348         __clear_page_buffers(page);
 349         put_page(page);
 350 }
 351
 352 /* read a page from a file.
 353  * We both read the page, and attach buffers to the page to record the
 354  * address of each block (using bmap).  These addresses will be used
 355  * to write the block later, completely bypassing the filesystem.
 356  * This usage is similar to how swap files are handled, and allows us
 357  * to write to a file with no concerns of memory allocation failing.
 358  */
 359 static int read_page(struct file *file, unsigned long index,
 360                      struct bitmap *bitmap,
 361                      unsigned long count,
 362                      struct page *page)
 363 {
 364         int ret = 0;
 365         struct inode *inode = file_inode(file);
 366         struct buffer_head *bh;
 367         sector_t block;
 368
 369         pr_debug("read bitmap file (%dB @ %llu)\n", (int)PAGE_SIZE,
 370                  (unsigned long long)index << PAGE_SHIFT);
 371
 372         bh = alloc_page_buffers(page, 1<<inode->i_blkbits, false);
 373         if (!bh) {
 374                 ret = -ENOMEM;
 375                 goto out;
 376         }
 377         attach_page_buffers(page, bh);
 378         block = index << (PAGE_SHIFT - inode->i_blkbits);
 379         while (bh) {
 380                 if (count == 0)
 381                         bh->b_blocknr = 0;
 382                 else {
 383                         bh->b_blocknr = bmap(inode, block);
 384                         if (bh->b_blocknr == 0) {
 385                                 /* Cannot use this file! */
 386                                 ret = -EINVAL;
 387                                 goto out;
 388                         }
 389                         bh->b_bdev = inode->i_sb->s_bdev;
 390                         if (count < (1<<inode->i_blkbits))
 391                                 count = 0;
 392                         else
 393                                 count -= (1<<inode->i_blkbits);
 394
 395                         bh->b_end_io = end_bitmap_write;
 396                         bh->b_private = bitmap;
 397                         atomic_inc(&bitmap->pending_writes);
 398                         set_buffer_locked(bh);
 399                         set_buffer_mapped(bh);
 400                         submit_bh(REQ_OP_READ, 0, bh);
 401                 }
 402                 block++;
 403                 bh = bh->b_this_page;
 404         }
 405         page->index = index;
 406
 407         wait_event(bitmap->write_wait,
 408                    atomic_read(&bitmap->pending_writes)==0);
 409         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
 410                 ret = -EIO;
 411 out:
 412         if (ret)
 413                 pr_err("md: bitmap read error: (%dB @ %llu): %d\n",
 414                        (int)PAGE_SIZE,
 415                        (unsigned long long)index << PAGE_SHIFT,
 416                        ret);
 417         return ret;
 418 }
 419
 420 /*
 421  * bitmap file superblock operations
 422  */
 423
 424 /*
 425  * md_bitmap_wait_writes() should be called before writing any bitmap
 426  * blocks, to ensure previous writes, particularly from
 427  * md_bitmap_daemon_work(), have completed.
 428  */
 429 static void md_bitmap_wait_writes(struct bitmap *bitmap)
 430 {
 431         if (bitmap->storage.file)
 432                 wait_event(bitmap->write_wait,
 433                            atomic_read(&bitmap->pending_writes)==0);
 434         else
 435                 /* Note that we ignore the return value.  The writes
 436                  * might have failed, but that would just mean that
 437                  * some bits which should be cleared haven't been,
 438                  * which is safe.  The relevant bitmap blocks will
 439                  * probably get written again, but there is no great
 440                  * loss if they aren't.
 441                  */
 442                 md_super_wait(bitmap->mddev);
 443 }
 444
 445
 446 /* update the event counter and sync the superblock to disk */
 447 void md_bitmap_update_sb(struct bitmap *bitmap)
 448 {
 449         bitmap_super_t *sb;
 450
 451         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
 452                 return;
 453         if (bitmap->mddev->bitmap_info.external)
 454                 return;
 455         if (!bitmap->storage.sb_page) /* no superblock */
 456                 return;
 457         sb = kmap_atomic(bitmap->storage.sb_page);
 458         sb->events = cpu_to_le64(bitmap->mddev->events);
 459         if (bitmap->mddev->events < bitmap->events_cleared)
 460                 /* rocking back to read-only */
 461                 bitmap->events_cleared = bitmap->mddev->events;
 462         sb->events_cleared = cpu_to_le64(bitmap->events_cleared);
 463         /*
 464          * clear BITMAP_WRITE_ERROR bit to protect against the case that
 465          * a bitmap write error occurred but the later writes succeeded.
 466          */
 467         sb->state = cpu_to_le32(bitmap->flags & ~BIT(BITMAP_WRITE_ERROR));
 468         /* Just in case these have been changed via sysfs: */
 469         sb->daemon_sleep = cpu_to_le32(bitmap->mddev->bitmap_info.daemon_sleep/HZ);
 470         sb->write_behind = cpu_to_le32(bitmap->mddev->bitmap_info.max_write_behind);
 471         /* This might have been changed by a reshape */
 472         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 473         sb->chunksize = cpu_to_le32(bitmap->mddev->bitmap_info.chunksize);
 474         sb->nodes = cpu_to_le32(bitmap->mddev->bitmap_info.nodes);
 475         sb->sectors_reserved = cpu_to_le32(bitmap->mddev->
 476                                            bitmap_info.space);
 477         kunmap_atomic(sb);
 478         write_page(bitmap, bitmap->storage.sb_page, 1);
 479 }
 480 EXPORT_SYMBOL(md_bitmap_update_sb);
 481
 482 /* print out the bitmap file superblock */
 483 void md_bitmap_print_sb(struct bitmap *bitmap)
 484 {
 485         bitmap_super_t *sb;
 486
 487         if (!bitmap || !bitmap->storage.sb_page)
 488                 return;
 489         sb = kmap_atomic(bitmap->storage.sb_page);
 490         pr_debug("%s: bitmap file superblock:\n", bmname(bitmap));
 491         pr_debug("         magic: %08x\n", le32_to_cpu(sb->magic));
 492         pr_debug("       version: %d\n", le32_to_cpu(sb->version));
 493         pr_debug("          uuid: %08x.%08x.%08x.%08x\n",
 494                  le32_to_cpu(*(__le32 *)(sb->uuid+0)),
 495                  le32_to_cpu(*(__le32 *)(sb->uuid+4)),
 496                  le32_to_cpu(*(__le32 *)(sb->uuid+8)),
 497                  le32_to_cpu(*(__le32 *)(sb->uuid+12)));
 498         pr_debug("        events: %llu\n",
 499                  (unsigned long long) le64_to_cpu(sb->events));
 500         pr_debug("events cleared: %llu\n",
 501                  (unsigned long long) le64_to_cpu(sb->events_cleared));
 502         pr_debug("         state: %08x\n", le32_to_cpu(sb->state));
 503         pr_debug("     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
 504         pr_debug("  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
 505         pr_debug("     sync size: %llu KB\n",
 506                  (unsigned long long)le64_to_cpu(sb->sync_size)/2);
 507         pr_debug("max write behind: %d\n", le32_to_cpu(sb->write_behind));
 508         kunmap_atomic(sb);
 509 }
 510
 511 /*
 512  * bitmap_new_disk_sb
 513  * @bitmap
 514  *
 515  * This function is somewhat the reverse of bitmap_read_sb.  bitmap_read_sb
 516  * reads and verifies the on-disk bitmap superblock and populates bitmap_info.
 517  * This function verifies 'bitmap_info' and populates the on-disk bitmap
 518  * structure, which is to be written to disk.
 519  *
 520  * Returns: 0 on success, -Exxx on error
 521  */
 522 static int md_bitmap_new_disk_sb(struct bitmap *bitmap)
 523 {
 524         bitmap_super_t *sb;
 525         unsigned long chunksize, daemon_sleep, write_behind;
 526
 527         bitmap->storage.sb_page = alloc_page(GFP_KERNEL | __GFP_ZERO);
 528         if (bitmap->storage.sb_page == NULL)
 529                 return -ENOMEM;
 530         bitmap->storage.sb_page->index = 0;
 531
 532         sb = kmap_atomic(bitmap->storage.sb_page);
 533
 534         sb->magic = cpu_to_le32(BITMAP_MAGIC);
 535         sb->version = cpu_to_le32(BITMAP_MAJOR_HI);
 536
 537         chunksize = bitmap->mddev->bitmap_info.chunksize;
 538         BUG_ON(!chunksize);
 539         if (!is_power_of_2(chunksize)) {
 540                 kunmap_atomic(sb);
 541                 pr_warn("bitmap chunksize not a power of 2\n");
 542                 return -EINVAL;
 543         }
 544         sb->chunksize = cpu_to_le32(chunksize);
 545
 546         daemon_sleep = bitmap->mddev->bitmap_info.daemon_sleep;
 547         if (!daemon_sleep || (daemon_sleep > MAX_SCHEDULE_TIMEOUT)) {
 548                 pr_debug("Choosing daemon_sleep default (5 sec)\n");
 549                 daemon_sleep = 5 * HZ;
 550         }
 551         sb->daemon_sleep = cpu_to_le32(daemon_sleep);
 552         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 553
 554         /*
 555          * FIXME: write_behind for RAID1.  If not specified, what
 556          * is a good choice?  We choose COUNTER_MAX / 2 arbitrarily.
 557          */
 558         write_behind = bitmap->mddev->bitmap_info.max_write_behind;
 559         if (write_behind > COUNTER_MAX)
 560                 write_behind = COUNTER_MAX / 2;
 561         sb->write_behind = cpu_to_le32(write_behind);
 562         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 563
 564         /* keep the array size field of the bitmap superblock up to date */
 565         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 566
 567         memcpy(sb->uuid, bitmap->mddev->uuid, 16);
 568
 569         set_bit(BITMAP_STALE, &bitmap->flags);
 570         sb->state = cpu_to_le32(bitmap->flags);
 571         bitmap->events_cleared = bitmap->mddev->events;
 572         sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
 573         bitmap->mddev->bitmap_info.nodes = 0;
 574
 575         kunmap_atomic(sb);
 576
 577         return 0;
 578 }
 579
 580 /* read the superblock from the bitmap file and initialize some bitmap fields */
 581 static int md_bitmap_read_sb(struct bitmap *bitmap)
 582 {
 583         char *reason = NULL;
 584         bitmap_super_t *sb;
 585         unsigned long chunksize, daemon_sleep, write_behind;
 586         unsigned long long events;
 587         int nodes = 0;
 588         unsigned long sectors_reserved = 0;
 589         int err = -EINVAL;
 590         struct page *sb_page;
 591         loff_t offset = bitmap->mddev->bitmap_info.offset;
 592
 593         if (!bitmap->storage.file && !bitmap->mddev->bitmap_info.offset) {
 594                 chunksize = 128 * 1024 * 1024;
 595                 daemon_sleep = 5 * HZ;
 596                 write_behind = 0;
 597                 set_bit(BITMAP_STALE, &bitmap->flags);
 598                 err = 0;
 599                 goto out_no_sb;
 600         }
 601         /* page 0 is the superblock, read it... */
 602         sb_page = alloc_page(GFP_KERNEL);
 603         if (!sb_page)
 604                 return -ENOMEM;
 605         bitmap->storage.sb_page = sb_page;
 606
 607 re_read:
 608         /* If cluster_slot is set, the cluster is setup */
 609         if (bitmap->cluster_slot >= 0) {
 610                 sector_t bm_blocks = bitmap->mddev->resync_max_sectors;
 611
 612                 sector_div(bm_blocks,
 613                            bitmap->mddev->bitmap_info.chunksize >> 9);
 614                 /* bits to bytes */
 615                 bm_blocks = ((bm_blocks+7) >> 3) + sizeof(bitmap_super_t);
 616                 /* to 4k blocks */
 617                 bm_blocks = DIV_ROUND_UP_SECTOR_T(bm_blocks, 4096);
 618                 offset = bitmap->mddev->bitmap_info.offset + (bitmap->cluster_slot * (bm_blocks << 3));
 619                 pr_debug("%s:%d bm slot: %d offset: %llu\n", __func__, __LINE__,
 620                         bitmap->cluster_slot, offset);
 621         }
 622
 623         if (bitmap->storage.file) {
 624                 loff_t isize = i_size_read(bitmap->storage.file->f_mapping->host);
 625                 int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
 626
 627                 err = read_page(bitmap->storage.file, 0,
 628                                 bitmap, bytes, sb_page);
 629         } else {
 630                 err = read_sb_page(bitmap->mddev,
 631                                    offset,
 632                                    sb_page,
 633                                    0, sizeof(bitmap_super_t));
 634         }
 635         if (err)
 636                 return err;
 637
 638         err = -EINVAL;
 639         sb = kmap_atomic(sb_page);
 640
 641         chunksize = le32_to_cpu(sb->chunksize);
 642         daemon_sleep = le32_to_cpu(sb->daemon_sleep) * HZ;
 643         write_behind = le32_to_cpu(sb->write_behind);
 644         sectors_reserved = le32_to_cpu(sb->sectors_reserved);
 645         /* Setup nodes/clustername only if bitmap version is
 646          * cluster-compatible
 647          */
 648         if (sb->version == cpu_to_le32(BITMAP_MAJOR_CLUSTERED)) {
 649                 nodes = le32_to_cpu(sb->nodes);
 650                 strlcpy(bitmap->mddev->bitmap_info.cluster_name,
 651                                 sb->cluster_name, 64);
 652         }
 653
 654         /* verify that the bitmap-specific fields are valid */
 655         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
 656                 reason = "bad magic";
 657         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
 658                  le32_to_cpu(sb->version) > BITMAP_MAJOR_CLUSTERED)
 659                 reason = "unrecognized superblock version";
 660         else if (chunksize < 512)
 661                 reason = "bitmap chunksize too small";
 662         else if (!is_power_of_2(chunksize))
 663                 reason = "bitmap chunksize not a power of 2";
 664         else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT)
 665                 reason = "daemon sleep period out of range";
 666         else if (write_behind > COUNTER_MAX)
 667                 reason = "write-behind limit out of range (0 - 16383)";
 668         if (reason) {
 669                 pr_warn("%s: invalid bitmap file superblock: %s\n",
 670                         bmname(bitmap), reason);
 671                 goto out;
 672         }
 673
 674         /* keep the array size field of the bitmap superblock up to date */
 675         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 676
 677         if (bitmap->mddev->persistent) {
 678                 /*
 679                  * We have a persistent array superblock, so compare the
 680                  * bitmap's UUID and event counter to the mddev's
 681                  */
 682                 if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
 683                         pr_warn("%s: bitmap superblock UUID mismatch\n",
 684                                 bmname(bitmap));
 685                         goto out;
 686                 }
 687                 events = le64_to_cpu(sb->events);
 688                 if (!nodes && (events < bitmap->mddev->events)) {
 689                         pr_warn("%s: bitmap file is out of date (%llu < %llu) -- forcing full recovery\n",
 690                                 bmname(bitmap), events,
 691                                 (unsigned long long) bitmap->mddev->events);
 692                         set_bit(BITMAP_STALE, &bitmap->flags);
 693                 }
 694         }
 695
 696         /* assign fields using values from superblock */
 697         bitmap->flags |= le32_to_cpu(sb->state);
 698         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
 699                 set_bit(BITMAP_HOSTENDIAN, &bitmap->flags);
 700         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
 701         strlcpy(bitmap->mddev->bitmap_info.cluster_name, sb->cluster_name, 64);
 702         err = 0;
 703
 704 out:
 705         kunmap_atomic(sb);
 706         /* Assigning chunksize is required for "re_read" */
 707         bitmap->mddev->bitmap_info.chunksize = chunksize;
 708         if (err == 0 && nodes && (bitmap->cluster_slot < 0)) {
 709                 err = md_setup_cluster(bitmap->mddev, nodes);
 710                 if (err) {
 711                         pr_warn("%s: Could not setup cluster service (%d)\n",
 712                                 bmname(bitmap), err);
 713                         goto out_no_sb;
 714                 }
 715                 bitmap->cluster_slot = md_cluster_ops->slot_number(bitmap->mddev);
 716                 goto re_read;
 717         }
 718
 719
 720 out_no_sb:
 721         if (test_bit(BITMAP_STALE, &bitmap->flags))
 722                 bitmap->events_cleared = bitmap->mddev->events;
 723         bitmap->mddev->bitmap_info.chunksize = chunksize;
 724         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 725         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 726         bitmap->mddev->bitmap_info.nodes = nodes;
 727         if (bitmap->mddev->bitmap_info.space == 0 ||
 728             bitmap->mddev->bitmap_info.space > sectors_reserved)
 729                 bitmap->mddev->bitmap_info.space = sectors_reserved;
 730         if (err) {
 731                 md_bitmap_print_sb(bitmap);
 732                 if (bitmap->cluster_slot < 0)
 733                         md_cluster_stop(bitmap->mddev);
 734         }
 735         return err;
 736 }
 737
 738 /*
 739  * general bitmap file operations
 740  */
 741
 742 /*
 743  * on-disk bitmap:
 744  *
 745  * Use one bit per "chunk" (block set). We do the disk I/O on the bitmap
 746  * file a page at a time. There's a superblock at the start of the file.
 747  */
 748 /* calculate the index of the page that contains this bit */
 749 static inline unsigned long file_page_index(struct bitmap_storage *store,
 750                                             unsigned long chunk)
 751 {
 752         if (store->sb_page)
 753                 chunk += sizeof(bitmap_super_t) << 3;
 754         return chunk >> PAGE_BIT_SHIFT;
 755 }
 756
 757 /* calculate the (bit) offset of this bit within a page */
 758 static inline unsigned long file_page_offset(struct bitmap_storage *store,
 759                                              unsigned long chunk)
 760 {
 761         if (store->sb_page)
 762                 chunk += sizeof(bitmap_super_t) << 3;
 763         return chunk & (PAGE_BITS - 1);
 764 }
 765
 766 /*
 767  * return a pointer to the page in the filemap that contains the given bit
 768  *
 769  */
 770 static inline struct page *filemap_get_page(struct bitmap_storage *store,
 771                                             unsigned long chunk)
 772 {
 773         if (file_page_index(store, chunk) >= store->file_pages)
 774                 return NULL;
 775         return store->filemap[file_page_index(store, chunk)];
 776 }
 777
 778 static int md_bitmap_storage_alloc(struct bitmap_storage *store,
 779                                    unsigned long chunks, int with_super,
 780                                    int slot_number)
 781 {
 782         int pnum, offset = 0;
 783         unsigned long num_pages;
 784         unsigned long bytes;
 785
 786         bytes = DIV_ROUND_UP(chunks, 8);
 787         if (with_super)
 788                 bytes += sizeof(bitmap_super_t);
 789
 790         num_pages = DIV_ROUND_UP(bytes, PAGE_SIZE);
 791         offset = slot_number * num_pages;
 792
 793         store->filemap = kmalloc_array(num_pages, sizeof(struct page *),
 794                                        GFP_KERNEL);
 795         if (!store->filemap)
 796                 return -ENOMEM;
 797
 798         if (with_super && !store->sb_page) {
 799                 store->sb_page = alloc_page(GFP_KERNEL|__GFP_ZERO);
 800                 if (store->sb_page == NULL)
 801                         return -ENOMEM;
 802         }
 803
 804         pnum = 0;
 805         if (store->sb_page) {
 806                 store->filemap[0] = store->sb_page;
 807                 pnum = 1;
 808                 store->sb_page->index = offset;
 809         }
 810
 811         for ( ; pnum < num_pages; pnum++) {
 812                 store->filemap[pnum] = alloc_page(GFP_KERNEL|__GFP_ZERO);
 813                 if (!store->filemap[pnum]) {
 814                         store->file_pages = pnum;
 815                         return -ENOMEM;
 816                 }
 817                 store->filemap[pnum]->index = pnum + offset;
 818         }
 819         store->file_pages = pnum;
 820
 821         /* We need 4 bits per page, rounded up to a multiple
 822          * of sizeof(unsigned long) */
 823         store->filemap_attr = kzalloc(
 824                 roundup(DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
 825                 GFP_KERNEL);
 826         if (!store->filemap_attr)
 827                 return -ENOMEM;
 828
 829         store->bytes = bytes;
 830
 831         return 0;
 832 }
 833
 834 static void md_bitmap_file_unmap(struct bitmap_storage *store)
 835 {
 836         struct page **map, *sb_page;
 837         int pages;
 838         struct file *file;
 839
 840         file = store->file;
 841         map = store->filemap;
 842         pages = store->file_pages;
 843         sb_page = store->sb_page;
 844
 845         while (pages--)
 846                 if (map[pages] != sb_page) /* 0 is sb_page, release it below */
 847                         free_buffers(map[pages]);
 848         kfree(map);
 849         kfree(store->filemap_attr);
 850
 851         if (sb_page)
 852                 free_buffers(sb_page);
 853
 854         if (file) {
 855                 struct inode *inode = file_inode(file);
 856                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
 857                 fput(file);
 858         }
 859 }
 860
 861 /*
 862  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
 863  * then it is no longer reliable, so we stop using it and we mark the file
 864  * as failed in the superblock
 865  */
 866 static void md_bitmap_file_kick(struct bitmap *bitmap)
 867 {
 868         char *path, *ptr = NULL;
 869
 870         if (!test_and_set_bit(BITMAP_STALE, &bitmap->flags)) {
 871                 md_bitmap_update_sb(bitmap);
 872
 873                 if (bitmap->storage.file) {
 874                         path = kmalloc(PAGE_SIZE, GFP_KERNEL);
 875                         if (path)
 876                                 ptr = file_path(bitmap->storage.file,
 877                                              path, PAGE_SIZE);
 878
 879                         pr_warn("%s: kicking failed bitmap file %s from array!\n",
 880                                 bmname(bitmap), IS_ERR(ptr) ? "" : ptr);
 881
 882                         kfree(path);
 883                 } else
 884                         pr_warn("%s: disabling internal bitmap due to errors\n",
 885                                 bmname(bitmap));
 886         }
 887 }
 888
 889 enum bitmap_page_attr {
 890         BITMAP_PAGE_DIRTY = 0,     /* there are set bits that need to be synced */
 891         BITMAP_PAGE_PENDING = 1,   /* there are bits that are being cleaned.
 892                                     * i.e. counter is 1 or 2. */
 893         BITMAP_PAGE_NEEDWRITE = 2, /* there are cleared bits that need to be synced */
 894 };
 895
 896 static inline void set_page_attr(struct bitmap *bitmap, int pnum,
 897                                  enum bitmap_page_attr attr)
 898 {
 899         set_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 900 }
 901
 902 static inline void clear_page_attr(struct bitmap *bitmap, int pnum,
 903                                    enum bitmap_page_attr attr)
 904 {
 905         clear_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 906 }
 907
 908 static inline int test_page_attr(struct bitmap *bitmap, int pnum,
 909                                  enum bitmap_page_attr attr)
 910 {
 911         return test_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 912 }
 913
 914 static inline int test_and_clear_page_attr(struct bitmap *bitmap, int pnum,
 915                                            enum bitmap_page_attr attr)
 916 {
 917         return test_and_clear_bit((pnum<<2) + attr,
 918                                   bitmap->storage.filemap_attr);
 919 }
 920 /*
 921  * bitmap_file_set_bit -- called before performing a write to the md device
 922  * to set (and eventually sync) a particular bit in the bitmap file
 923  *
 924  * we set the bit immediately, then we record the page number so that
 925  * when an unplug occurs, we can flush the dirty pages out to disk
 926  */
 927 static void md_bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 928 {
 929         unsigned long bit;
 930         struct page *page;
 931         void *kaddr;
 932         unsigned long chunk = block >> bitmap->counts.chunkshift;
 933         struct bitmap_storage *store = &bitmap->storage;
 934         unsigned long node_offset = 0;
 935
 936         if (mddev_is_clustered(bitmap->mddev))
 937                 node_offset = bitmap->cluster_slot * store->file_pages;
 938
 939         page = filemap_get_page(&bitmap->storage, chunk);
 940         if (!page)
 941                 return;
 942         bit = file_page_offset(&bitmap->storage, chunk);
 943
 944         /* set the bit */
 945         kaddr = kmap_atomic(page);
 946         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
 947                 set_bit(bit, kaddr);
 948         else
 949                 set_bit_le(bit, kaddr);
 950         kunmap_atomic(kaddr);
 951         pr_debug("set file bit %lu page %lu\n", bit, page->index);
 952         /* record page number so it gets flushed to disk when unplug occurs */
 953         set_page_attr(bitmap, page->index - node_offset, BITMAP_PAGE_DIRTY);
 954 }
 955
 956 static void md_bitmap_file_clear_bit(struct bitmap *bitmap, sector_t block)
 957 {
 958         unsigned long bit;
 959         struct page *page;
 960         void *paddr;
 961         unsigned long chunk = block >> bitmap->counts.chunkshift;
 962         struct bitmap_storage *store = &bitmap->storage;
 963         unsigned long node_offset = 0;
 964
 965         if (mddev_is_clustered(bitmap->mddev))
 966                 node_offset = bitmap->cluster_slot * store->file_pages;
 967
 968         page = filemap_get_page(&bitmap->storage, chunk);
 969         if (!page)
 970                 return;
 971         bit = file_page_offset(&bitmap->storage, chunk);
 972         paddr = kmap_atomic(page);
 973         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
 974                 clear_bit(bit, paddr);
 975         else
 976                 clear_bit_le(bit, paddr);
 977         kunmap_atomic(paddr);
 978         if (!test_page_attr(bitmap, page->index - node_offset, BITMAP_PAGE_NEEDWRITE)) {
 979                 set_page_attr(bitmap, page->index - node_offset, BITMAP_PAGE_PENDING);
 980                 bitmap->allclean = 0;
 981         }
 982 }
 983
 984 static int md_bitmap_file_test_bit(struct bitmap *bitmap, sector_t block)
 985 {
 986         unsigned long bit;
 987         struct page *page;
 988         void *paddr;
 989         unsigned long chunk = block >> bitmap->counts.chunkshift;
 990         int set = 0;
 991
 992         page = filemap_get_page(&bitmap->storage, chunk);
 993         if (!page)
 994                 return -EINVAL;
 995         bit = file_page_offset(&bitmap->storage, chunk);
 996         paddr = kmap_atomic(page);
 997         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
 998                 set = test_bit(bit, paddr);
 999         else
1000                 set = test_bit_le(bit, paddr);
1001         kunmap_atomic(paddr);
1002         return set;
1003 }
1004
1005
1006 /* this gets called when the md device is ready to unplug its underlying
1007  * (slave) device queues -- before we let any writes go down, we need to
1008  * sync the dirty pages of the bitmap file to disk */
1009 void md_bitmap_unplug(struct bitmap *bitmap)
1010 {
1011         unsigned long i;
1012         int dirty, need_write;
1013         int writing = 0;
1014
1015         if (!bitmap || !bitmap->storage.filemap ||
1016             test_bit(BITMAP_STALE, &bitmap->flags))
1017                 return;
1018
1019         /* look at each page to see if there are any set bits that need to be
1020          * flushed out to disk */
1021         for (i = 0; i < bitmap->storage.file_pages; i++) {
1022                 if (!bitmap->storage.filemap)
1023                         return;
1024                 dirty = test_and_clear_page_attr(bitmap, i, BITMAP_PAGE_DIRTY);
1025                 need_write = test_and_clear_page_attr(bitmap, i,
1026                                                       BITMAP_PAGE_NEEDWRITE);
1027                 if (dirty || need_write) {
1028                         if (!writing) {
1029                                 md_bitmap_wait_writes(bitmap);
1030                                 if (bitmap->mddev->queue)
1031                                         blk_add_trace_msg(bitmap->mddev->queue,
1032                                                           "md bitmap_unplug");
1033                         }
1034                         clear_page_attr(bitmap, i, BITMAP_PAGE_PENDING);
1035                         write_page(bitmap, bitmap->storage.filemap[i], 0);
1036                         writing = 1;
1037                 }
1038         }
1039         if (writing)
1040                 md_bitmap_wait_writes(bitmap);
1041
1042         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
1043                 md_bitmap_file_kick(bitmap);
1044 }
1045 EXPORT_SYMBOL(md_bitmap_unplug);
1046
1047 static void md_bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
1048 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
1049  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
1050  * memory mapping of the bitmap file
1051  * Special cases:
1052  *   if there's no bitmap file, or if the bitmap file had been
1053  *   previously kicked from the array, we mark all the bits as
1054  *   1's in order to cause a full resync.
1055  *
1056  * We ignore all bits for sectors that end earlier than 'start'.
1057  * This is used when reading an out-of-date bitmap...
1058  */
1059 static int md_bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
1060 {
1061         unsigned long i, chunks, index, oldindex, bit, node_offset = 0;
1062         struct page *page = NULL;
1063         unsigned long bit_cnt = 0;
1064         struct file *file;
1065         unsigned long offset;
1066         int outofdate;
1067         int ret = -ENOSPC;
1068         void *paddr;
1069         struct bitmap_storage *store = &bitmap->storage;
1070
1071         chunks = bitmap->counts.chunks;
1072         file = store->file;
1073
1074         if (!file && !bitmap->mddev->bitmap_info.offset) {
1075                 /* No permanent bitmap - fill with '1s'. */
1076                 store->filemap = NULL;
1077                 store->file_pages = 0;
1078                 for (i = 0; i < chunks ; i++) {
1079                         /* if the disk bit is set, set the memory bit */
1080                         int needed = ((sector_t)(i+1) << (bitmap->counts.chunkshift)
1081                                       >= start);
1082                         md_bitmap_set_memory_bits(bitmap,
1083                                                   (sector_t)i << bitmap->counts.chunkshift,
1084                                                   needed);
1085                 }
1086                 return 0;
1087         }
1088
1089         outofdate = test_bit(BITMAP_STALE, &bitmap->flags);
1090         if (outofdate)
1091                 pr_warn("%s: bitmap file is out of date, doing full recovery\n", bmname(bitmap));
1092
1093         if (file && i_size_read(file->f_mapping->host) < store->bytes) {
1094                 pr_warn("%s: bitmap file too short %lu < %lu\n",
1095                         bmname(bitmap),
1096                         (unsigned long) i_size_read(file->f_mapping->host),
1097                         store->bytes);
1098                 goto err;
1099         }
1100
1101         oldindex = ~0L;
1102         offset = 0;
1103         if (!bitmap->mddev->bitmap_info.external)
1104                 offset = sizeof(bitmap_super_t);
1105
1106         if (mddev_is_clustered(bitmap->mddev))
1107                 node_offset = bitmap->cluster_slot * (DIV_ROUND_UP(store->bytes, PAGE_SIZE));
1108
1109         for (i = 0; i < chunks; i++) {
1110                 int b;
1111                 index = file_page_index(&bitmap->storage, i);
1112                 bit = file_page_offset(&bitmap->storage, i);
1113                 if (index != oldindex) { /* this is a new page, read it in */
1114                         int count;
1115                         /* unmap the old page, we're done with it */
1116                         if (index == store->file_pages-1)
1117                                 count = store->bytes - index * PAGE_SIZE;
1118                         else
1119                                 count = PAGE_SIZE;
1120                         page = store->filemap[index];
1121                         if (file)
1122                                 ret = read_page(file, index, bitmap,
1123                                                 count, page);
1124                         else
1125                                 ret = read_sb_page(
1126                                         bitmap->mddev,
1127                                         bitmap->mddev->bitmap_info.offset,
1128                                         page,
1129                                         index + node_offset, count);
1130
1131                         if (ret)
1132                                 goto err;
1133
1134                         oldindex = index;
1135
1136                         if (outofdate) {
1137                                 /*
1138                                  * if bitmap is out of date, dirty the
1139                                  * whole page and write it out
1140                                  */
1141                                 paddr = kmap_atomic(page);
1142                                 memset(paddr + offset, 0xff,
1143                                        PAGE_SIZE - offset);
1144                                 kunmap_atomic(paddr);
1145                                 write_page(bitmap, page, 1);
1146
1147                                 ret = -EIO;
1148                                 if (test_bit(BITMAP_WRITE_ERROR,
1149                                              &bitmap->flags))
1150                                         goto err;
1151                         }
1152                 }
1153                 paddr = kmap_atomic(page);
1154                 if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
1155                         b = test_bit(bit, paddr);
1156                 else
1157                         b = test_bit_le(bit, paddr);
1158                 kunmap_atomic(paddr);
1159                 if (b) {
1160                         /* if the disk bit is set, set the memory bit */
1161                         int needed = ((sector_t)(i+1) << bitmap->counts.chunkshift
1162                                       >= start);
1163                         md_bitmap_set_memory_bits(bitmap,
1164                                                   (sector_t)i << bitmap->counts.chunkshift,
1165                                                   needed);
1166                         bit_cnt++;
1167                 }
1168                 offset = 0;
1169         }
1170
1171         pr_debug("%s: bitmap initialized from disk: read %lu pages, set %lu of %lu bits\n",
1172                  bmname(bitmap), store->file_pages,
1173                  bit_cnt, chunks);
1174
1175         return 0;
1176
1177  err:
1178         pr_warn("%s: bitmap initialisation failed: %d\n",
1179                 bmname(bitmap), ret);
1180         return ret;
1181 }
1182
1183 void md_bitmap_write_all(struct bitmap *bitmap)
1184 {
1185         /* We don't actually write all bitmap blocks here,
1186          * just flag them as needing to be written
1187          */
1188         int i;
1189
1190         if (!bitmap || !bitmap->storage.filemap)
1191                 return;
1192         if (bitmap->storage.file)
1193                 /* Only one copy, so nothing needed */
1194                 return;
1195
1196         for (i = 0; i < bitmap->storage.file_pages; i++)
1197                 set_page_attr(bitmap, i,
1198                               BITMAP_PAGE_NEEDWRITE);
1199         bitmap->allclean = 0;
1200 }
1201
1202 static void md_bitmap_count_page(struct bitmap_counts *bitmap,
1203                                  sector_t offset, int inc)
1204 {
1205         sector_t chunk = offset >> bitmap->chunkshift;
1206         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1207         bitmap->bp[page].count += inc;
1208         md_bitmap_checkfree(bitmap, page);
1209 }
1210
1211 static void md_bitmap_set_pending(struct bitmap_counts *bitmap, sector_t offset)
1212 {
1213         sector_t chunk = offset >> bitmap->chunkshift;
1214         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1215         struct bitmap_page *bp = &bitmap->bp[page];
1216
1217         if (!bp->pending)
1218                 bp->pending = 1;
1219 }
1220
1221 static bitmap_counter_t *md_bitmap_get_counter(struct bitmap_counts *bitmap,
1222                                                sector_t offset, sector_t *blocks,
1223                                                int create);
1224
1225 /*
1226  * bitmap daemon -- periodically wakes up to clean bits and flush pages
1227  *                      out to disk
1228  */
1229
1230 void md_bitmap_daemon_work(struct mddev *mddev)
1231 {
1232         struct bitmap *bitmap;
1233         unsigned long j;
1234         unsigned long nextpage;
1235         sector_t blocks;
1236         struct bitmap_counts *counts;
1237
1238         /* Use a mutex to guard daemon_work against
1239          * bitmap_destroy.
1240          */
1241         mutex_lock(&mddev->bitmap_info.mutex);
1242         bitmap = mddev->bitmap;
1243         if (bitmap == NULL) {
1244                 mutex_unlock(&mddev->bitmap_info.mutex);
1245                 return;
1246         }
1247         if (time_before(jiffies, bitmap->daemon_lastrun
1248                         + mddev->bitmap_info.daemon_sleep))
1249                 goto done;
1250
1251         bitmap->daemon_lastrun = jiffies;
1252         if (bitmap->allclean) {
1253                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1254                 goto done;
1255         }
1256         bitmap->allclean = 1;
1257
1258         if (bitmap->mddev->queue)
1259                 blk_add_trace_msg(bitmap->mddev->queue,
1260                                   "md bitmap_daemon_work");
1261
1262         /* Any file-page which is PENDING now needs to be written.
1263          * So set NEEDWRITE now, then after we make any last-minute changes
1264          * we will write it.
1265          */
1266         for (j = 0; j < bitmap->storage.file_pages; j++)
1267                 if (test_and_clear_page_attr(bitmap, j,
1268                                              BITMAP_PAGE_PENDING))
1269                         set_page_attr(bitmap, j,
1270                                       BITMAP_PAGE_NEEDWRITE);
1271
1272         if (bitmap->need_sync &&
1273             mddev->bitmap_info.external == 0) {
1274                 /* Arrange for superblock update as well as
1275                  * other changes */
1276                 bitmap_super_t *sb;
1277                 bitmap->need_sync = 0;
1278                 if (bitmap->storage.filemap) {
1279                         sb = kmap_atomic(bitmap->storage.sb_page);
1280                         sb->events_cleared =
1281                                 cpu_to_le64(bitmap->events_cleared);
1282                         kunmap_atomic(sb);
1283                         set_page_attr(bitmap, 0,
1284                                       BITMAP_PAGE_NEEDWRITE);
1285                 }
1286         }
1287         /* Now look at the bitmap counters and if any are '2' or '1',
1288          * decrement and handle accordingly.
1289          */
1290         counts = &bitmap->counts;
1291         spin_lock_irq(&counts->lock);
1292         nextpage = 0;
1293         for (j = 0; j < counts->chunks; j++) {
1294                 bitmap_counter_t *bmc;
1295                 sector_t  block = (sector_t)j << counts->chunkshift;
1296
1297                 if (j == nextpage) {
1298                         nextpage += PAGE_COUNTER_RATIO;
1299                         if (!counts->bp[j >> PAGE_COUNTER_SHIFT].pending) {
1300                                 j |= PAGE_COUNTER_MASK;
1301                                 continue;
1302                         }
1303                         counts->bp[j >> PAGE_COUNTER_SHIFT].pending = 0;
1304                 }
1305
1306                 bmc = md_bitmap_get_counter(counts, block, &blocks, 0);
1307                 if (!bmc) {
1308                         j |= PAGE_COUNTER_MASK;
1309                         continue;
1310                 }
1311                 if (*bmc == 1 && !bitmap->need_sync) {
1312                         /* We can clear the bit */
1313                         *bmc = 0;
1314                         md_bitmap_count_page(counts, block, -1);
1315                         md_bitmap_file_clear_bit(bitmap, block);
1316                 } else if (*bmc && *bmc <= 2) {
1317                         *bmc = 1;
1318                         md_bitmap_set_pending(counts, block);
1319                         bitmap->allclean = 0;
1320                 }
1321         }
1322         spin_unlock_irq(&counts->lock);
1323
1324         md_bitmap_wait_writes(bitmap);
1325         /* Now start writeout on any page in NEEDWRITE that isn't DIRTY.
1326          * DIRTY pages need to be written by bitmap_unplug so it can wait
1327          * for them.
1328          * If we find any DIRTY page we stop there and let bitmap_unplug
1329          * handle all the rest.  This is important in the case where
1330          * the first blocking holds the superblock and it has been updated.
1331          * We mustn't write any other blocks before the superblock.
1332          */
1333         for (j = 0;
1334              j < bitmap->storage.file_pages
1335                      && !test_bit(BITMAP_STALE, &bitmap->flags);
1336              j++) {
1337                 if (test_page_attr(bitmap, j,
1338                                    BITMAP_PAGE_DIRTY))
1339                         /* bitmap_unplug will handle the rest */
1340                         break;
1341                 if (test_and_clear_page_attr(bitmap, j,
1342                                              BITMAP_PAGE_NEEDWRITE)) {
1343                         write_page(bitmap, bitmap->storage.filemap[j], 0);
1344                 }
1345         }
1346
1347  done:
1348         if (bitmap->allclean == 0)
1349                 mddev->thread->timeout =
1350                         mddev->bitmap_info.daemon_sleep;
1351         mutex_unlock(&mddev->bitmap_info.mutex);
1352 }
1353
1354 static bitmap_counter_t *md_bitmap_get_counter(struct bitmap_counts *bitmap,
1355                                                sector_t offset, sector_t *blocks,
1356                                                int create)
1357 __releases(bitmap->lock)
1358 __acquires(bitmap->lock)
1359 {
1360         /* If 'create', we might release the lock and reclaim it.
1361          * The lock must have been taken with interrupts enabled.
1362          * If !create, we don't release the lock.
1363          */
1364         sector_t chunk = offset >> bitmap->chunkshift;
1365         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1366         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1367         sector_t csize;
1368         int err;
1369
1370         err = md_bitmap_checkpage(bitmap, page, create, 0);
1371
1372         if (bitmap->bp[page].hijacked ||
1373             bitmap->bp[page].map == NULL)
1374                 csize = ((sector_t)1) << (bitmap->chunkshift +
1375                                           PAGE_COUNTER_SHIFT - 1);
1376         else
1377                 csize = ((sector_t)1) << bitmap->chunkshift;
1378         *blocks = csize - (offset & (csize - 1));
1379
1380         if (err < 0)
1381                 return NULL;
1382
1383         /* now locked ... */
1384
1385         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1386                 /* should we use the first or second counter field
1387                  * of the hijacked pointer? */
1388                 int hi = (pageoff > PAGE_COUNTER_MASK);
1389                 return  &((bitmap_counter_t *)
1390                           &bitmap->bp[page].map)[hi];
1391         } else /* page is allocated */
1392                 return (bitmap_counter_t *)
1393                         &(bitmap->bp[page].map[pageoff]);
1394 }
1395
1396 int md_bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1397 {
1398         if (!bitmap)
1399                 return 0;
1400
1401         if (behind) {
1402                 int bw;
1403                 atomic_inc(&bitmap->behind_writes);
1404                 bw = atomic_read(&bitmap->behind_writes);
1405                 if (bw > bitmap->behind_writes_used)
1406                         bitmap->behind_writes_used = bw;
1407
1408                 pr_debug("inc write-behind count %d/%lu\n",
1409                          bw, bitmap->mddev->bitmap_info.max_write_behind);
1410         }
1411
1412         while (sectors) {
1413                 sector_t blocks;
1414                 bitmap_counter_t *bmc;
1415
1416                 spin_lock_irq(&bitmap->counts.lock);
1417                 bmc = md_bitmap_get_counter(&bitmap->counts, offset, &blocks, 1);
1418                 if (!bmc) {
1419                         spin_unlock_irq(&bitmap->counts.lock);
1420                         return 0;
1421                 }
1422
1423                 if (unlikely(COUNTER(*bmc) == COUNTER_MAX)) {
1424                         DEFINE_WAIT(__wait);
1425                         /* note that it is safe to do the prepare_to_wait
1426                          * after the test as long as we do it before dropping
1427                          * the spinlock.
1428                          */
1429                         prepare_to_wait(&bitmap->overflow_wait, &__wait,
1430                                         TASK_UNINTERRUPTIBLE);
1431                         spin_unlock_irq(&bitmap->counts.lock);
1432                         schedule();
1433                         finish_wait(&bitmap->overflow_wait, &__wait);
1434                         continue;
1435                 }
1436
1437                 switch (*bmc) {
1438                 case 0:
1439                         md_bitmap_file_set_bit(bitmap, offset);
1440                         md_bitmap_count_page(&bitmap->counts, offset, 1);
1441                         /* fall through */
1442                 case 1:
1443                         *bmc = 2;
1444                 }
1445
1446                 (*bmc)++;
1447
1448                 spin_unlock_irq(&bitmap->counts.lock);
1449
1450                 offset += blocks;
1451                 if (sectors > blocks)
1452                         sectors -= blocks;
1453                 else
1454                         sectors = 0;
1455         }
1456         return 0;
1457 }
1458 EXPORT_SYMBOL(md_bitmap_startwrite);
1459
1460 void md_bitmap_endwrite(struct bitmap *bitmap, sector_t offset,
1461                         unsigned long sectors, int success, int behind)
1462 {
1463         if (!bitmap)
1464                 return;
1465         if (behind) {
1466                 if (atomic_dec_and_test(&bitmap->behind_writes))
1467                         wake_up(&bitmap->behind_wait);
1468                 pr_debug("dec write-behind count %d/%lu\n",
1469                          atomic_read(&bitmap->behind_writes),
1470                          bitmap->mddev->bitmap_info.max_write_behind);
1471         }
1472
1473         while (sectors) {
1474                 sector_t blocks;
1475                 unsigned long flags;
1476                 bitmap_counter_t *bmc;
1477
1478                 spin_lock_irqsave(&bitmap->counts.lock, flags);
1479                 bmc = md_bitmap_get_counter(&bitmap->counts, offset, &blocks, 0);
1480                 if (!bmc) {
1481                         spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1482                         return;
1483                 }
1484
1485                 if (success && !bitmap->mddev->degraded &&
1486                     bitmap->events_cleared < bitmap->mddev->events) {
1487                         bitmap->events_cleared = bitmap->mddev->events;
1488                         bitmap->need_sync = 1;
1489                         sysfs_notify_dirent_safe(bitmap->sysfs_can_clear);
1490                 }
1491
1492                 if (!success && !NEEDED(*bmc))
1493                         *bmc |= NEEDED_MASK;
1494
1495                 if (COUNTER(*bmc) == COUNTER_MAX)
1496                         wake_up(&bitmap->overflow_wait);
1497
1498                 (*bmc)--;
1499                 if (*bmc <= 2) {
1500                         md_bitmap_set_pending(&bitmap->counts, offset);
1501                         bitmap->allclean = 0;
1502                 }
1503                 spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1504                 offset += blocks;
1505                 if (sectors > blocks)
1506                         sectors -= blocks;
1507                 else
1508                         sectors = 0;
1509         }
1510 }
1511 EXPORT_SYMBOL(md_bitmap_endwrite);
1512
1513 static int __bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1514                                int degraded)
1515 {
1516         bitmap_counter_t *bmc;
1517         int rv;
1518         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1519                 *blocks = 1024;
1520                 return 1; /* always resync if no bitmap */
1521         }
1522         spin_lock_irq(&bitmap->counts.lock);
1523         bmc = md_bitmap_get_counter(&bitmap->counts, offset, blocks, 0);
1524         rv = 0;
1525         if (bmc) {
1526                 /* locked */
1527                 if (RESYNC(*bmc))
1528                         rv = 1;
1529                 else if (NEEDED(*bmc)) {
1530                         rv = 1;
1531                         if (!degraded) { /* don't set/clear bits if degraded */
1532                                 *bmc |= RESYNC_MASK;
1533                                 *bmc &= ~NEEDED_MASK;
1534                         }
1535                 }
1536         }
1537         spin_unlock_irq(&bitmap->counts.lock);
1538         return rv;
1539 }
1540
1541 int md_bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1542                          int degraded)
1543 {
1544         /* bitmap_start_sync must always report on multiples of whole
1545          * pages, otherwise resync (which is very PAGE_SIZE based) will
1546          * get confused.
1547          * So call __bitmap_start_sync repeatedly (if needed) until
1548          * At least PAGE_SIZE>>9 blocks are covered.
1549          * Return the 'or' of the result.
1550          */
1551         int rv = 0;
1552         sector_t blocks1;
1553
1554         *blocks = 0;
1555         while (*blocks < (PAGE_SIZE>>9)) {
1556                 rv |= __bitmap_start_sync(bitmap, offset,
1557                                           &blocks1, degraded);
1558                 offset += blocks1;
1559                 *blocks += blocks1;
1560         }
1561         return rv;
1562 }
1563 EXPORT_SYMBOL(md_bitmap_start_sync);
1564
1565 void md_bitmap_end_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks, int aborted)
1566 {
1567         bitmap_counter_t *bmc;
1568         unsigned long flags;
1569
1570         if (bitmap == NULL) {
1571                 *blocks = 1024;
1572                 return;
1573         }
1574         spin_lock_irqsave(&bitmap->counts.lock, flags);
1575         bmc = md_bitmap_get_counter(&bitmap->counts, offset, blocks, 0);
1576         if (bmc == NULL)
1577                 goto unlock;
1578         /* locked */
1579         if (RESYNC(*bmc)) {
1580                 *bmc &= ~RESYNC_MASK;
1581
1582                 if (!NEEDED(*bmc) && aborted)
1583                         *bmc |= NEEDED_MASK;
1584                 else {
1585                         if (*bmc <= 2) {
1586                                 md_bitmap_set_pending(&bitmap->counts, offset);
1587                                 bitmap->allclean = 0;
1588                         }
1589                 }
1590         }
1591  unlock:
1592         spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1593 }
1594 EXPORT_SYMBOL(md_bitmap_end_sync);
1595
1596 void md_bitmap_close_sync(struct bitmap *bitmap)
1597 {
1598         /* Sync has finished, and any bitmap chunks that weren't synced
1599          * properly have been aborted.  It remains to us to clear the
1600          * RESYNC bit wherever it is still on
1601          */
1602         sector_t sector = 0;
1603         sector_t blocks;
1604         if (!bitmap)
1605                 return;
1606         while (sector < bitmap->mddev->resync_max_sectors) {
1607                 md_bitmap_end_sync(bitmap, sector, &blocks, 0);
1608                 sector += blocks;
1609         }
1610 }
1611 EXPORT_SYMBOL(md_bitmap_close_sync);
1612
1613 void md_bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector, bool force)
1614 {
1615         sector_t s = 0;
1616         sector_t blocks;
1617
1618         if (!bitmap)
1619                 return;
1620         if (sector == 0) {
1621                 bitmap->last_end_sync = jiffies;
1622                 return;
1623         }
1624         if (!force && time_before(jiffies, (bitmap->last_end_sync
1625                                   + bitmap->mddev->bitmap_info.daemon_sleep)))
1626                 return;
1627         wait_event(bitmap->mddev->recovery_wait,
1628                    atomic_read(&bitmap->mddev->recovery_active) == 0);
1629
1630         bitmap->mddev->curr_resync_completed = sector;
1631         set_bit(MD_SB_CHANGE_CLEAN, &bitmap->mddev->sb_flags);
1632         sector &= ~((1ULL << bitmap->counts.chunkshift) - 1);
1633         s = 0;
1634         while (s < sector && s < bitmap->mddev->resync_max_sectors) {
1635                 md_bitmap_end_sync(bitmap, s, &blocks, 0);
1636                 s += blocks;
1637         }
1638         bitmap->last_end_sync = jiffies;
1639         sysfs_notify(&bitmap->mddev->kobj, NULL, "sync_completed");
1640 }
1641 EXPORT_SYMBOL(md_bitmap_cond_end_sync);
1642
1643 void md_bitmap_sync_with_cluster(struct mddev *mddev,
1644                               sector_t old_lo, sector_t old_hi,
1645                               sector_t new_lo, sector_t new_hi)
1646 {
1647         struct bitmap *bitmap = mddev->bitmap;
1648         sector_t sector, blocks = 0;
1649
1650         for (sector = old_lo; sector < new_lo; ) {
1651                 md_bitmap_end_sync(bitmap, sector, &blocks, 0);
1652                 sector += blocks;
1653         }
1654         WARN((blocks > new_lo) && old_lo, "alignment is not correct for lo\n");
1655
1656         for (sector = old_hi; sector < new_hi; ) {
1657                 md_bitmap_start_sync(bitmap, sector, &blocks, 0);
1658                 sector += blocks;
1659         }
1660         WARN((blocks > new_hi) && old_hi, "alignment is not correct for hi\n");
1661 }
1662 EXPORT_SYMBOL(md_bitmap_sync_with_cluster);
1663
1664 static void md_bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1665 {
1666         /* For each chunk covered by any of these sectors, set the
1667          * counter to 2 and possibly set resync_needed.  They should all
1668          * be 0 at this point
1669          */
1670
1671         sector_t secs;
1672         bitmap_counter_t *bmc;
1673         spin_lock_irq(&bitmap->counts.lock);
1674         bmc = md_bitmap_get_counter(&bitmap->counts, offset, &secs, 1);
1675         if (!bmc) {
1676                 spin_unlock_irq(&bitmap->counts.lock);
1677                 return;
1678         }
1679         if (!*bmc) {
1680                 *bmc = 2;
1681                 md_bitmap_count_page(&bitmap->counts, offset, 1);
1682                 md_bitmap_set_pending(&bitmap->counts, offset);
1683                 bitmap->allclean = 0;
1684         }
1685         if (needed)
1686                 *bmc |= NEEDED_MASK;
1687         spin_unlock_irq(&bitmap->counts.lock);
1688 }
1689
1690 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
1691 void md_bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1692 {
1693         unsigned long chunk;
1694
1695         for (chunk = s; chunk <= e; chunk++) {
1696                 sector_t sec = (sector_t)chunk << bitmap->counts.chunkshift;
1697                 md_bitmap_set_memory_bits(bitmap, sec, 1);
1698                 md_bitmap_file_set_bit(bitmap, sec);
1699                 if (sec < bitmap->mddev->recovery_cp)
1700                         /* We are asserting that the array is dirty,
1701                          * so move the recovery_cp address back so
1702                          * that it is obvious that it is dirty
1703                          */
1704                         bitmap->mddev->recovery_cp = sec;
1705         }
1706 }
1707
1708 /*
1709  * flush out any pending updates
1710  */
1711 void md_bitmap_flush(struct mddev *mddev)
1712 {
1713         struct bitmap *bitmap = mddev->bitmap;
1714         long sleep;
1715
1716         if (!bitmap) /* there was no bitmap */
1717                 return;
1718
1719         /* run the daemon_work three time to ensure everything is flushed
1720          * that can be
1721          */
1722         sleep = mddev->bitmap_info.daemon_sleep * 2;
1723         bitmap->daemon_lastrun -= sleep;
1724         md_bitmap_daemon_work(mddev);
1725         bitmap->daemon_lastrun -= sleep;
1726         md_bitmap_daemon_work(mddev);
1727         bitmap->daemon_lastrun -= sleep;
1728         md_bitmap_daemon_work(mddev);
1729         md_bitmap_update_sb(bitmap);
1730 }
1731
1732 /*
1733  * free memory that was allocated
1734  */
1735 void md_bitmap_free(struct bitmap *bitmap)
1736 {
1737         unsigned long k, pages;
1738         struct bitmap_page *bp;
1739
1740         if (!bitmap) /* there was no bitmap */
1741                 return;
1742
1743         if (bitmap->sysfs_can_clear)
1744                 sysfs_put(bitmap->sysfs_can_clear);
1745
1746         if (mddev_is_clustered(bitmap->mddev) && bitmap->mddev->cluster_info &&
1747                 bitmap->cluster_slot == md_cluster_ops->slot_number(bitmap->mddev))
1748                 md_cluster_stop(bitmap->mddev);
1749
1750         /* Shouldn't be needed - but just in case.... */
1751         wait_event(bitmap->write_wait,
1752                    atomic_read(&bitmap->pending_writes) == 0);
1753
1754         /* release the bitmap file  */
1755         md_bitmap_file_unmap(&bitmap->storage);
1756
1757         bp = bitmap->counts.bp;
1758         pages = bitmap->counts.pages;
1759
1760         /* free all allocated memory */
1761
1762         if (bp) /* deallocate the page memory */
1763                 for (k = 0; k < pages; k++)
1764                         if (bp[k].map && !bp[k].hijacked)
1765                                 kfree(bp[k].map);
1766         kfree(bp);
1767         kfree(bitmap);
1768 }
1769 EXPORT_SYMBOL(md_bitmap_free);
1770
1771 void md_bitmap_wait_behind_writes(struct mddev *mddev)
1772 {
1773         struct bitmap *bitmap = mddev->bitmap;
1774
1775         /* wait for behind writes to complete */
1776         if (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
1777                 pr_debug("md:%s: behind writes in progress - waiting to stop.\n",
1778                          mdname(mddev));
1779                 /* need to kick something here to make sure I/O goes? */
1780                 wait_event(bitmap->behind_wait,
1781                            atomic_read(&bitmap->behind_writes) == 0);
1782         }
1783 }
1784
1785 void md_bitmap_destroy(struct mddev *mddev)
1786 {
1787         struct bitmap *bitmap = mddev->bitmap;
1788
1789         if (!bitmap) /* there was no bitmap */
1790                 return;
1791
1792         md_bitmap_wait_behind_writes(mddev);
1793         mempool_destroy(mddev->wb_info_pool);
1794         mddev->wb_info_pool = NULL;
1795
1796         mutex_lock(&mddev->bitmap_info.mutex);
1797         spin_lock(&mddev->lock);
1798         mddev->bitmap = NULL; /* disconnect from the md device */
1799         spin_unlock(&mddev->lock);
1800         mutex_unlock(&mddev->bitmap_info.mutex);
1801         if (mddev->thread)
1802                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1803
1804         md_bitmap_free(bitmap);
1805 }
1806
1807 /*
1808  * initialize the bitmap structure
1809  * if this returns an error, bitmap_destroy must be called to do clean up
1810  * once mddev->bitmap is set
1811  */
1812 struct bitmap *md_bitmap_create(struct mddev *mddev, int slot)
1813 {
1814         struct bitmap *bitmap;
1815         sector_t blocks = mddev->resync_max_sectors;
1816         struct file *file = mddev->bitmap_info.file;
1817         int err;
1818         struct kernfs_node *bm = NULL;
1819
1820         BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
1821
1822         BUG_ON(file && mddev->bitmap_info.offset);
1823
1824         if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
1825                 pr_notice("md/raid:%s: array with journal cannot have bitmap\n",
1826                           mdname(mddev));
1827                 return ERR_PTR(-EBUSY);
1828         }
1829
1830         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1831         if (!bitmap)
1832                 return ERR_PTR(-ENOMEM);
1833
1834         spin_lock_init(&bitmap->counts.lock);
1835         atomic_set(&bitmap->pending_writes, 0);
1836         init_waitqueue_head(&bitmap->write_wait);
1837         init_waitqueue_head(&bitmap->overflow_wait);
1838         init_waitqueue_head(&bitmap->behind_wait);
1839
1840         bitmap->mddev = mddev;
1841         bitmap->cluster_slot = slot;
1842
1843         if (mddev->kobj.sd)
1844                 bm = sysfs_get_dirent(mddev->kobj.sd, "bitmap");
1845         if (bm) {
1846                 bitmap->sysfs_can_clear = sysfs_get_dirent(bm, "can_clear");
1847                 sysfs_put(bm);
1848         } else
1849                 bitmap->sysfs_can_clear = NULL;
1850
1851         bitmap->storage.file = file;
1852         if (file) {
1853                 get_file(file);
1854                 /* As future accesses to this file will use bmap,
1855                  * and bypass the page cache, we must sync the file
1856                  * first.
1857                  */
1858                 vfs_fsync(file, 1);
1859         }
1860         /* read superblock from bitmap file (this sets mddev->bitmap_info.chunksize) */
1861         if (!mddev->bitmap_info.external) {
1862                 /*
1863                  * If 'MD_ARRAY_FIRST_USE' is set, then device-mapper is
1864                  * instructing us to create a new on-disk bitmap instance.
1865                  */
1866                 if (test_and_clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags))
1867                         err = md_bitmap_new_disk_sb(bitmap);
1868                 else
1869                         err = md_bitmap_read_sb(bitmap);
1870         } else {
1871                 err = 0;
1872                 if (mddev->bitmap_info.chunksize == 0 ||
1873                     mddev->bitmap_info.daemon_sleep == 0)
1874                         /* chunksize and time_base need to be
1875                          * set first. */
1876                         err = -EINVAL;
1877         }
1878         if (err)
1879                 goto error;
1880
1881         bitmap->daemon_lastrun = jiffies;
1882         err = md_bitmap_resize(bitmap, blocks, mddev->bitmap_info.chunksize, 1);
1883         if (err)
1884                 goto error;
1885
1886         pr_debug("created bitmap (%lu pages) for device %s\n",
1887                  bitmap->counts.pages, bmname(bitmap));
1888
1889         err = test_bit(BITMAP_WRITE_ERROR, &bitmap->flags) ? -EIO : 0;
1890         if (err)
1891                 goto error;
1892
1893         return bitmap;
1894  error:
1895         md_bitmap_free(bitmap);
1896         return ERR_PTR(err);
1897 }
1898
1899 int md_bitmap_load(struct mddev *mddev)
1900 {
1901         int err = 0;
1902         sector_t start = 0;
1903         sector_t sector = 0;
1904         struct bitmap *bitmap = mddev->bitmap;
1905         struct md_rdev *rdev;
1906
1907         if (!bitmap)
1908                 goto out;
1909
1910         rdev_for_each(rdev, mddev)
1911                 mddev_create_wb_pool(mddev, rdev, true);
1912
1913         if (mddev_is_clustered(mddev))
1914                 md_cluster_ops->load_bitmaps(mddev, mddev->bitmap_info.nodes);
1915
1916         /* Clear out old bitmap info first:  Either there is none, or we
1917          * are resuming after someone else has possibly changed things,
1918          * so we should forget old cached info.
1919          * All chunks should be clean, but some might need_sync.
1920          */
1921         while (sector < mddev->resync_max_sectors) {
1922                 sector_t blocks;
1923                 md_bitmap_start_sync(bitmap, sector, &blocks, 0);
1924                 sector += blocks;
1925         }
1926         md_bitmap_close_sync(bitmap);
1927
1928         if (mddev->degraded == 0
1929             || bitmap->events_cleared == mddev->events)
1930                 /* no need to keep dirty bits to optimise a
1931                  * re-add of a missing device */
1932                 start = mddev->recovery_cp;
1933
1934         mutex_lock(&mddev->bitmap_info.mutex);
1935         err = md_bitmap_init_from_disk(bitmap, start);
1936         mutex_unlock(&mddev->bitmap_info.mutex);
1937
1938         if (err)
1939                 goto out;
1940         clear_bit(BITMAP_STALE, &bitmap->flags);
1941
1942         /* Kick recovery in case any bits were set */
1943         set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
1944
1945         mddev->thread->timeout = mddev->bitmap_info.daemon_sleep;
1946         md_wakeup_thread(mddev->thread);
1947
1948         md_bitmap_update_sb(bitmap);
1949
1950         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
1951                 err = -EIO;
1952 out:
1953         return err;
1954 }
1955 EXPORT_SYMBOL_GPL(md_bitmap_load);
1956
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
2021         return rv;
2022 }
2023 EXPORT_SYMBOL_GPL(md_bitmap_copy_from_slot);
2024
2025
2026 void md_bitmap_status(struct seq_file *seq, struct bitmap *bitmap)
2027 {
2028         unsigned long chunk_kb;
2029         struct bitmap_counts *counts;
2030
2031         if (!bitmap)
2032                 return;
2033
2034         counts = &bitmap->counts;
2035
2036         chunk_kb = bitmap->mddev->bitmap_info.chunksize >> 10;
2037         seq_printf(seq, "bitmap: %lu/%lu pages [%luKB], "
2038                    "%lu%s chunk",
2039                    counts->pages - counts->missing_pages,
2040                    counts->pages,
2041                    (counts->pages - counts->missing_pages)
2042                    << (PAGE_SHIFT - 10),
2043                    chunk_kb ? chunk_kb : bitmap->mddev->bitmap_info.chunksize,
2044                    chunk_kb ? "KB" : "B");
2045         if (bitmap->storage.file) {
2046                 seq_printf(seq, ", file: ");
2047                 seq_file_path(seq, bitmap->storage.file, " \t\n");
2048         }
2049
2050         seq_printf(seq, "\n");
2051 }
2052
2053 int md_bitmap_resize(struct bitmap *bitmap, sector_t blocks,
2054                   int chunksize, int init)
2055 {
2056         /* If chunk_size is 0, choose an appropriate chunk size.
2057          * Then possibly allocate new storage space.
2058          * Then quiesce, copy bits, replace bitmap, and re-start
2059          *
2060          * This function is called both to set up the initial bitmap
2061          * and to resize the bitmap while the array is active.
2062          * If this happens as a result of the array being resized,
2063          * chunksize will be zero, and we need to choose a suitable
2064          * chunksize, otherwise we use what we are given.
2065          */
2066         struct bitmap_storage store;
2067         struct bitmap_counts old_counts;
2068         unsigned long chunks;
2069         sector_t block;
2070         sector_t old_blocks, new_blocks;
2071         int chunkshift;
2072         int ret = 0;
2073         long pages;
2074         struct bitmap_page *new_bp;
2075
2076         if (bitmap->storage.file && !init) {
2077                 pr_info("md: cannot resize file-based bitmap\n");
2078                 return -EINVAL;
2079         }
2080
2081         if (chunksize == 0) {
2082                 /* If there is enough space, leave the chunk size unchanged,
2083                  * else increase by factor of two until there is enough space.
2084                  */
2085                 long bytes;
2086                 long space = bitmap->mddev->bitmap_info.space;
2087
2088                 if (space == 0) {
2089                         /* We don't know how much space there is, so limit
2090                          * to current size - in sectors.
2091                          */
2092                         bytes = DIV_ROUND_UP(bitmap->counts.chunks, 8);
2093                         if (!bitmap->mddev->bitmap_info.external)
2094                                 bytes += sizeof(bitmap_super_t);
2095                         space = DIV_ROUND_UP(bytes, 512);
2096                         bitmap->mddev->bitmap_info.space = space;
2097                 }
2098                 chunkshift = bitmap->counts.chunkshift;
2099                 chunkshift--;
2100                 do {
2101                         /* 'chunkshift' is shift from block size to chunk size */
2102                         chunkshift++;
2103                         chunks = DIV_ROUND_UP_SECTOR_T(blocks, 1 << chunkshift);
2104                         bytes = DIV_ROUND_UP(chunks, 8);
2105                         if (!bitmap->mddev->bitmap_info.external)
2106                                 bytes += sizeof(bitmap_super_t);
2107                 } while (bytes > (space << 9));
2108         } else
2109                 chunkshift = ffz(~chunksize) - BITMAP_BLOCK_SHIFT;
2110
2111         chunks = DIV_ROUND_UP_SECTOR_T(blocks, 1 << chunkshift);
2112         memset(&store, 0, sizeof(store));
2113         if (bitmap->mddev->bitmap_info.offset || bitmap->mddev->bitmap_info.file)
2114                 ret = md_bitmap_storage_alloc(&store, chunks,
2115                                               !bitmap->mddev->bitmap_info.external,
2116                                               mddev_is_clustered(bitmap->mddev)
2117                                               ? bitmap->cluster_slot : 0);
2118         if (ret) {
2119                 md_bitmap_file_unmap(&store);
2120                 goto err;
2121         }
2122
2123         pages = DIV_ROUND_UP(chunks, PAGE_COUNTER_RATIO);
2124
2125         new_bp = kcalloc(pages, sizeof(*new_bp), GFP_KERNEL);
2126         ret = -ENOMEM;
2127         if (!new_bp) {
2128                 md_bitmap_file_unmap(&store);
2129                 goto err;
2130         }
2131
2132         if (!init)
2133                 bitmap->mddev->pers->quiesce(bitmap->mddev, 1);
2134
2135         store.file = bitmap->storage.file;
2136         bitmap->storage.file = NULL;
2137
2138         if (store.sb_page && bitmap->storage.sb_page)
2139                 memcpy(page_address(store.sb_page),
2140                        page_address(bitmap->storage.sb_page),
2141                        sizeof(bitmap_super_t));
2142         md_bitmap_file_unmap(&bitmap->storage);
2143         bitmap->storage = store;
2144
2145         old_counts = bitmap->counts;
2146         bitmap->counts.bp = new_bp;
2147         bitmap->counts.pages = pages;
2148         bitmap->counts.missing_pages = pages;
2149         bitmap->counts.chunkshift = chunkshift;
2150         bitmap->counts.chunks = chunks;
2151         bitmap->mddev->bitmap_info.chunksize = 1 << (chunkshift +
2152                                                      BITMAP_BLOCK_SHIFT);
2153
2154         blocks = min(old_counts.chunks << old_counts.chunkshift,
2155                      chunks << chunkshift);
2156
2157         spin_lock_irq(&bitmap->counts.lock);
2158         /* For cluster raid, need to pre-allocate bitmap */
2159         if (mddev_is_clustered(bitmap->mddev)) {
2160                 unsigned long page;
2161                 for (page = 0; page < pages; page++) {
2162                         ret = md_bitmap_checkpage(&bitmap->counts, page, 1, 1);
2163                         if (ret) {
2164                                 unsigned long k;
2165
2166                                 /* deallocate the page memory */
2167                                 for (k = 0; k < page; k++) {
2168                                         kfree(new_bp[k].map);
2169                                 }
2170                                 kfree(new_bp);
2171
2172                                 /* restore some fields from old_counts */
2173                                 bitmap->counts.bp = old_counts.bp;
2174                                 bitmap->counts.pages = old_counts.pages;
2175                                 bitmap->counts.missing_pages = old_counts.pages;
2176                                 bitmap->counts.chunkshift = old_counts.chunkshift;
2177                                 bitmap->counts.chunks = old_counts.chunks;
2178                                 bitmap->mddev->bitmap_info.chunksize = 1 << (old_counts.chunkshift +
2179                                                                              BITMAP_BLOCK_SHIFT);
2180                                 blocks = old_counts.chunks << old_counts.chunkshift;
2181                                 pr_warn("Could not pre-allocate in-memory bitmap for cluster raid\n");
2182                                 break;
2183                         } else
2184                                 bitmap->counts.bp[page].count += 1;
2185                 }
2186         }
2187
2188         for (block = 0; block < blocks; ) {
2189                 bitmap_counter_t *bmc_old, *bmc_new;
2190                 int set;
2191
2192                 bmc_old = md_bitmap_get_counter(&old_counts, block, &old_blocks, 0);
2193                 set = bmc_old && NEEDED(*bmc_old);
2194
2195                 if (set) {
2196                         bmc_new = md_bitmap_get_counter(&bitmap->counts, block, &new_blocks, 1);
2197                         if (*bmc_new == 0) {
2198                                 /* need to set on-disk bits too. */
2199                                 sector_t end = block + new_blocks;
2200                                 sector_t start = block >> chunkshift;
2201                                 start <<= chunkshift;
2202                                 while (start < end) {
2203                                         md_bitmap_file_set_bit(bitmap, block);
2204                                         start += 1 << chunkshift;
2205                                 }
2206                                 *bmc_new = 2;
2207                                 md_bitmap_count_page(&bitmap->counts, block, 1);
2208                                 md_bitmap_set_pending(&bitmap->counts, block);
2209                         }
2210                         *bmc_new |= NEEDED_MASK;
2211                         if (new_blocks < old_blocks)
2212                                 old_blocks = new_blocks;
2213                 }
2214                 block += old_blocks;
2215         }
2216
2217         if (bitmap->counts.bp != old_counts.bp) {
2218                 unsigned long k;
2219                 for (k = 0; k < old_counts.pages; k++)
2220                         if (!old_counts.bp[k].hijacked)
2221                                 kfree(old_counts.bp[k].map);
2222                 kfree(old_counts.bp);
2223         }
2224
2225         if (!init) {
2226                 int i;
2227                 while (block < (chunks << chunkshift)) {
2228                         bitmap_counter_t *bmc;
2229                         bmc = md_bitmap_get_counter(&bitmap->counts, block, &new_blocks, 1);
2230                         if (bmc) {
2231                                 /* new space.  It needs to be resynced, so
2232                                  * we set NEEDED_MASK.
2233                                  */
2234                                 if (*bmc == 0) {
2235                                         *bmc = NEEDED_MASK | 2;
2236                                         md_bitmap_count_page(&bitmap->counts, block, 1);
2237                                         md_bitmap_set_pending(&bitmap->counts, block);
2238                                 }
2239                         }
2240                         block += new_blocks;
2241                 }
2242                 for (i = 0; i < bitmap->storage.file_pages; i++)
2243                         set_page_attr(bitmap, i, BITMAP_PAGE_DIRTY);
2244         }
2245         spin_unlock_irq(&bitmap->counts.lock);
2246
2247         if (!init) {
2248                 md_bitmap_unplug(bitmap);
2249                 bitmap->mddev->pers->quiesce(bitmap->mddev, 0);
2250         }
2251         ret = 0;
2252 err:
2253         return ret;
2254 }
2255 EXPORT_SYMBOL_GPL(md_bitmap_resize);
2256
2257 static ssize_t
2258 location_show(struct mddev *mddev, char *page)
2259 {
2260         ssize_t len;
2261         if (mddev->bitmap_info.file)
2262                 len = sprintf(page, "file");
2263         else if (mddev->bitmap_info.offset)
2264                 len = sprintf(page, "%+lld", (long long)mddev->bitmap_info.offset);
2265         else
2266                 len = sprintf(page, "none");
2267         len += sprintf(page+len, "\n");
2268         return len;
2269 }
2270
2271 static ssize_t
2272 location_store(struct mddev *mddev, const char *buf, size_t len)
2273 {
2274         int rv;
2275
2276         rv = mddev_lock(mddev);
2277         if (rv)
2278                 return rv;
2279         if (mddev->pers) {
2280                 if (!mddev->pers->quiesce) {
2281                         rv = -EBUSY;
2282                         goto out;
2283                 }
2284                 if (mddev->recovery || mddev->sync_thread) {
2285                         rv = -EBUSY;
2286                         goto out;
2287                 }
2288         }
2289
2290         if (mddev->bitmap || mddev->bitmap_info.file ||
2291             mddev->bitmap_info.offset) {
2292                 /* bitmap already configured.  Only option is to clear it */
2293                 if (strncmp(buf, "none", 4) != 0) {
2294                         rv = -EBUSY;
2295                         goto out;
2296                 }
2297                 if (mddev->pers) {
2298                         mddev_suspend(mddev);
2299                         md_bitmap_destroy(mddev);
2300                         mddev_resume(mddev);
2301                 }
2302                 mddev->bitmap_info.offset = 0;
2303                 if (mddev->bitmap_info.file) {
2304                         struct file *f = mddev->bitmap_info.file;
2305                         mddev->bitmap_info.file = NULL;
2306                         fput(f);
2307                 }
2308         } else {
2309                 /* No bitmap, OK to set a location */
2310                 long long offset;
2311                 if (strncmp(buf, "none", 4) == 0)
2312                         /* nothing to be done */;
2313                 else if (strncmp(buf, "file:", 5) == 0) {
2314                         /* Not supported yet */
2315                         rv = -EINVAL;
2316                         goto out;
2317                 } else {
2318                         if (buf[0] == '+')
2319                                 rv = kstrtoll(buf+1, 10, &offset);
2320                         else
2321                                 rv = kstrtoll(buf, 10, &offset);
2322                         if (rv)
2323                                 goto out;
2324                         if (offset == 0) {
2325                                 rv = -EINVAL;
2326                                 goto out;
2327                         }
2328                         if (mddev->bitmap_info.external == 0 &&
2329                             mddev->major_version == 0 &&
2330                             offset != mddev->bitmap_info.default_offset) {
2331                                 rv = -EINVAL;
2332                                 goto out;
2333                         }
2334                         mddev->bitmap_info.offset = offset;
2335                         if (mddev->pers) {
2336                                 struct bitmap *bitmap;
2337                                 bitmap = md_bitmap_create(mddev, -1);
2338                                 mddev_suspend(mddev);
2339                                 if (IS_ERR(bitmap))
2340                                         rv = PTR_ERR(bitmap);
2341                                 else {
2342                                         mddev->bitmap = bitmap;
2343                                         rv = md_bitmap_load(mddev);
2344                                         if (rv)
2345                                                 mddev->bitmap_info.offset = 0;
2346                                 }
2347                                 if (rv) {
2348                                         md_bitmap_destroy(mddev);
2349                                         mddev_resume(mddev);
2350                                         goto out;
2351                                 }
2352                                 mddev_resume(mddev);
2353                         }
2354                 }
2355         }
2356         if (!mddev->external) {
2357                 /* Ensure new bitmap info is stored in
2358                  * metadata promptly.
2359                  */
2360                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
2361                 md_wakeup_thread(mddev->thread);
2362         }
2363         rv = 0;
2364 out:
2365         mddev_unlock(mddev);
2366         if (rv)
2367                 return rv;
2368         return len;
2369 }
2370
2371 static struct md_sysfs_entry bitmap_location =
2372 __ATTR(location, S_IRUGO|S_IWUSR, location_show, location_store);
2373
2374 /* 'bitmap/space' is the space available at 'location' for the
2375  * bitmap.  This allows the kernel to know when it is safe to
2376  * resize the bitmap to match a resized array.
2377  */
2378 static ssize_t
2379 space_show(struct mddev *mddev, char *page)
2380 {
2381         return sprintf(page, "%lu\n", mddev->bitmap_info.space);
2382 }
2383
2384 static ssize_t
2385 space_store(struct mddev *mddev, const char *buf, size_t len)
2386 {
2387         unsigned long sectors;
2388         int rv;
2389
2390         rv = kstrtoul(buf, 10, &sectors);
2391         if (rv)
2392                 return rv;
2393
2394         if (sectors == 0)
2395                 return -EINVAL;
2396
2397         if (mddev->bitmap &&
2398             sectors < (mddev->bitmap->storage.bytes + 511) >> 9)
2399                 return -EFBIG; /* Bitmap is too big for this small space */
2400
2401         /* could make sure it isn't too big, but that isn't really
2402          * needed - user-space should be careful.
2403          */
2404         mddev->bitmap_info.space = sectors;
2405         return len;
2406 }
2407
2408 static struct md_sysfs_entry bitmap_space =
2409 __ATTR(space, S_IRUGO|S_IWUSR, space_show, space_store);
2410
2411 static ssize_t
2412 timeout_show(struct mddev *mddev, char *page)
2413 {
2414         ssize_t len;
2415         unsigned long secs = mddev->bitmap_info.daemon_sleep / HZ;
2416         unsigned long jifs = mddev->bitmap_info.daemon_sleep % HZ;
2417
2418         len = sprintf(page, "%lu", secs);
2419         if (jifs)
2420                 len += sprintf(page+len, ".%03u", jiffies_to_msecs(jifs));
2421         len += sprintf(page+len, "\n");
2422         return len;
2423 }
2424
2425 static ssize_t
2426 timeout_store(struct mddev *mddev, const char *buf, size_t len)
2427 {
2428         /* timeout can be set at any time */
2429         unsigned long timeout;
2430         int rv = strict_strtoul_scaled(buf, &timeout, 4);
2431         if (rv)
2432                 return rv;
2433
2434         /* just to make sure we don't overflow... */
2435         if (timeout >= LONG_MAX / HZ)
2436                 return -EINVAL;
2437
2438         timeout = timeout * HZ / 10000;
2439
2440         if (timeout >= MAX_SCHEDULE_TIMEOUT)
2441                 timeout = MAX_SCHEDULE_TIMEOUT-1;
2442         if (timeout < 1)
2443                 timeout = 1;
2444         mddev->bitmap_info.daemon_sleep = timeout;
2445         if (mddev->thread) {
2446                 /* if thread->timeout is MAX_SCHEDULE_TIMEOUT, then
2447                  * the bitmap is all clean and we don't need to
2448                  * adjust the timeout right now
2449                  */
2450                 if (mddev->thread->timeout < MAX_SCHEDULE_TIMEOUT) {
2451                         mddev->thread->timeout = timeout;
2452                         md_wakeup_thread(mddev->thread);
2453                 }
2454         }
2455         return len;
2456 }
2457
2458 static struct md_sysfs_entry bitmap_timeout =
2459 __ATTR(time_base, S_IRUGO|S_IWUSR, timeout_show, timeout_store);
2460
2461 static ssize_t
2462 backlog_show(struct mddev *mddev, char *page)
2463 {
2464         return sprintf(page, "%lu\n", mddev->bitmap_info.max_write_behind);
2465 }
2466
2467 static ssize_t
2468 backlog_store(struct mddev *mddev, const char *buf, size_t len)
2469 {
2470         unsigned long backlog;
2471         unsigned long old_mwb = mddev->bitmap_info.max_write_behind;
2472         int rv = kstrtoul(buf, 10, &backlog);
2473         if (rv)
2474                 return rv;
2475         if (backlog > COUNTER_MAX)
2476                 return -EINVAL;
2477         mddev->bitmap_info.max_write_behind = backlog;
2478         if (!backlog && mddev->wb_info_pool) {
2479                 /* wb_info_pool is not needed if backlog is zero */
2480                 mempool_destroy(mddev->wb_info_pool);
2481                 mddev->wb_info_pool = NULL;
2482         } else if (backlog && !mddev->wb_info_pool) {
2483                 /* wb_info_pool is needed since backlog is not zero */
2484                 struct md_rdev *rdev;
2485
2486                 rdev_for_each(rdev, mddev)
2487                         mddev_create_wb_pool(mddev, rdev, false);
2488         }
2489         if (old_mwb != backlog)
2490                 md_bitmap_update_sb(mddev->bitmap);
2491         return len;
2492 }
2493
2494 static struct md_sysfs_entry bitmap_backlog =
2495 __ATTR(backlog, S_IRUGO|S_IWUSR, backlog_show, backlog_store);
2496
2497 static ssize_t
2498 chunksize_show(struct mddev *mddev, char *page)
2499 {
2500         return sprintf(page, "%lu\n", mddev->bitmap_info.chunksize);
2501 }
2502
2503 static ssize_t
2504 chunksize_store(struct mddev *mddev, const char *buf, size_t len)
2505 {
2506         /* Can only be changed when no bitmap is active */
2507         int rv;
2508         unsigned long csize;
2509         if (mddev->bitmap)
2510                 return -EBUSY;
2511         rv = kstrtoul(buf, 10, &csize);
2512         if (rv)
2513                 return rv;
2514         if (csize < 512 ||
2515             !is_power_of_2(csize))
2516                 return -EINVAL;
2517         mddev->bitmap_info.chunksize = csize;
2518         return len;
2519 }
2520
2521 static struct md_sysfs_entry bitmap_chunksize =
2522 __ATTR(chunksize, S_IRUGO|S_IWUSR, chunksize_show, chunksize_store);
2523
2524 static ssize_t metadata_show(struct mddev *mddev, char *page)
2525 {
2526         if (mddev_is_clustered(mddev))
2527                 return sprintf(page, "clustered\n");
2528         return sprintf(page, "%s\n", (mddev->bitmap_info.external
2529                                       ? "external" : "internal"));
2530 }
2531
2532 static ssize_t metadata_store(struct mddev *mddev, const char *buf, size_t len)
2533 {
2534         if (mddev->bitmap ||
2535             mddev->bitmap_info.file ||
2536             mddev->bitmap_info.offset)
2537                 return -EBUSY;
2538         if (strncmp(buf, "external", 8) == 0)
2539                 mddev->bitmap_info.external = 1;
2540         else if ((strncmp(buf, "internal", 8) == 0) ||
2541                         (strncmp(buf, "clustered", 9) == 0))
2542                 mddev->bitmap_info.external = 0;
2543         else
2544                 return -EINVAL;
2545         return len;
2546 }
2547
2548 static struct md_sysfs_entry bitmap_metadata =
2549 __ATTR(metadata, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
2550
2551 static ssize_t can_clear_show(struct mddev *mddev, char *page)
2552 {
2553         int len;
2554         spin_lock(&mddev->lock);
2555         if (mddev->bitmap)
2556                 len = sprintf(page, "%s\n", (mddev->bitmap->need_sync ?
2557                                              "false" : "true"));
2558         else
2559                 len = sprintf(page, "\n");
2560         spin_unlock(&mddev->lock);
2561         return len;
2562 }
2563
2564 static ssize_t can_clear_store(struct mddev *mddev, const char *buf, size_t len)
2565 {
2566         if (mddev->bitmap == NULL)
2567                 return -ENOENT;
2568         if (strncmp(buf, "false", 5) == 0)
2569                 mddev->bitmap->need_sync = 1;
2570         else if (strncmp(buf, "true", 4) == 0) {
2571                 if (mddev->degraded)
2572                         return -EBUSY;
2573                 mddev->bitmap->need_sync = 0;
2574         } else
2575                 return -EINVAL;
2576         return len;
2577 }
2578
2579 static struct md_sysfs_entry bitmap_can_clear =
2580 __ATTR(can_clear, S_IRUGO|S_IWUSR, can_clear_show, can_clear_store);
2581
2582 static ssize_t
2583 behind_writes_used_show(struct mddev *mddev, char *page)
2584 {
2585         ssize_t ret;
2586         spin_lock(&mddev->lock);
2587         if (mddev->bitmap == NULL)
2588                 ret = sprintf(page, "0\n");
2589         else
2590                 ret = sprintf(page, "%lu\n",
2591                               mddev->bitmap->behind_writes_used);
2592         spin_unlock(&mddev->lock);
2593         return ret;
2594 }
2595
2596 static ssize_t
2597 behind_writes_used_reset(struct mddev *mddev, const char *buf, size_t len)
2598 {
2599         if (mddev->bitmap)
2600                 mddev->bitmap->behind_writes_used = 0;
2601         return len;
2602 }
2603
2604 static struct md_sysfs_entry max_backlog_used =
2605 __ATTR(max_backlog_used, S_IRUGO | S_IWUSR,
2606        behind_writes_used_show, behind_writes_used_reset);
2607
2608 static struct attribute *md_bitmap_attrs[] = {
2609         &bitmap_location.attr,
2610         &bitmap_space.attr,
2611         &bitmap_timeout.attr,
2612         &bitmap_backlog.attr,
2613         &bitmap_chunksize.attr,
2614         &bitmap_metadata.attr,
2615         &bitmap_can_clear.attr,
2616         &max_backlog_used.attr,
2617         NULL
2618 };
2619 struct attribute_group md_bitmap_group = {
2620         .name = "bitmap",
2621         .attrs = md_bitmap_attrs,
2622 };
2623