drivers/md/bitmap.c

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