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 EXPORT_SYMBOL(bitmap_update_sb);
 475
 476 /* print out the bitmap file superblock */
 477 void bitmap_print_sb(struct bitmap *bitmap)
 478 {
 479         bitmap_super_t *sb;
 480
 481         if (!bitmap || !bitmap->storage.sb_page)
 482                 return;
 483         sb = kmap_atomic(bitmap->storage.sb_page);
 484         pr_debug("%s: bitmap file superblock:\n", bmname(bitmap));
 485         pr_debug("         magic: %08x\n", le32_to_cpu(sb->magic));
 486         pr_debug("       version: %d\n", le32_to_cpu(sb->version));
 487         pr_debug("          uuid: %08x.%08x.%08x.%08x\n",
 488                  le32_to_cpu(*(__u32 *)(sb->uuid+0)),
 489                  le32_to_cpu(*(__u32 *)(sb->uuid+4)),
 490                  le32_to_cpu(*(__u32 *)(sb->uuid+8)),
 491                  le32_to_cpu(*(__u32 *)(sb->uuid+12)));
 492         pr_debug("        events: %llu\n",
 493                  (unsigned long long) le64_to_cpu(sb->events));
 494         pr_debug("events cleared: %llu\n",
 495                  (unsigned long long) le64_to_cpu(sb->events_cleared));
 496         pr_debug("         state: %08x\n", le32_to_cpu(sb->state));
 497         pr_debug("     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
 498         pr_debug("  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
 499         pr_debug("     sync size: %llu KB\n",
 500                  (unsigned long long)le64_to_cpu(sb->sync_size)/2);
 501         pr_debug("max write behind: %d\n", le32_to_cpu(sb->write_behind));
 502         kunmap_atomic(sb);
 503 }
 504
 505 /*
 506  * bitmap_new_disk_sb
 507  * @bitmap
 508  *
 509  * This function is somewhat the reverse of bitmap_read_sb.  bitmap_read_sb
 510  * reads and verifies the on-disk bitmap superblock and populates bitmap_info.
 511  * This function verifies 'bitmap_info' and populates the on-disk bitmap
 512  * structure, which is to be written to disk.
 513  *
 514  * Returns: 0 on success, -Exxx on error
 515  */
 516 static int bitmap_new_disk_sb(struct bitmap *bitmap)
 517 {
 518         bitmap_super_t *sb;
 519         unsigned long chunksize, daemon_sleep, write_behind;
 520
 521         bitmap->storage.sb_page = alloc_page(GFP_KERNEL | __GFP_ZERO);
 522         if (bitmap->storage.sb_page == NULL)
 523                 return -ENOMEM;
 524         bitmap->storage.sb_page->index = 0;
 525
 526         sb = kmap_atomic(bitmap->storage.sb_page);
 527
 528         sb->magic = cpu_to_le32(BITMAP_MAGIC);
 529         sb->version = cpu_to_le32(BITMAP_MAJOR_HI);
 530
 531         chunksize = bitmap->mddev->bitmap_info.chunksize;
 532         BUG_ON(!chunksize);
 533         if (!is_power_of_2(chunksize)) {
 534                 kunmap_atomic(sb);
 535                 pr_warn("bitmap chunksize not a power of 2\n");
 536                 return -EINVAL;
 537         }
 538         sb->chunksize = cpu_to_le32(chunksize);
 539
 540         daemon_sleep = bitmap->mddev->bitmap_info.daemon_sleep;
 541         if (!daemon_sleep || (daemon_sleep > MAX_SCHEDULE_TIMEOUT)) {
 542                 pr_debug("Choosing daemon_sleep default (5 sec)\n");
 543                 daemon_sleep = 5 * HZ;
 544         }
 545         sb->daemon_sleep = cpu_to_le32(daemon_sleep);
 546         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 547
 548         /*
 549          * FIXME: write_behind for RAID1.  If not specified, what
 550          * is a good choice?  We choose COUNTER_MAX / 2 arbitrarily.
 551          */
 552         write_behind = bitmap->mddev->bitmap_info.max_write_behind;
 553         if (write_behind > COUNTER_MAX)
 554                 write_behind = COUNTER_MAX / 2;
 555         sb->write_behind = cpu_to_le32(write_behind);
 556         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 557
 558         /* keep the array size field of the bitmap superblock up to date */
 559         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 560
 561         memcpy(sb->uuid, bitmap->mddev->uuid, 16);
 562
 563         set_bit(BITMAP_STALE, &bitmap->flags);
 564         sb->state = cpu_to_le32(bitmap->flags);
 565         bitmap->events_cleared = bitmap->mddev->events;
 566         sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
 567         bitmap->mddev->bitmap_info.nodes = 0;
 568
 569         kunmap_atomic(sb);
 570
 571         return 0;
 572 }
 573
 574 /* read the superblock from the bitmap file and initialize some bitmap fields */
 575 static int bitmap_read_sb(struct bitmap *bitmap)
 576 {
 577         char *reason = NULL;
 578         bitmap_super_t *sb;
 579         unsigned long chunksize, daemon_sleep, write_behind;
 580         unsigned long long events;
 581         int nodes = 0;
 582         unsigned long sectors_reserved = 0;
 583         int err = -EINVAL;
 584         struct page *sb_page;
 585         loff_t offset = bitmap->mddev->bitmap_info.offset;
 586
 587         if (!bitmap->storage.file && !bitmap->mddev->bitmap_info.offset) {
 588                 chunksize = 128 * 1024 * 1024;
 589                 daemon_sleep = 5 * HZ;
 590                 write_behind = 0;
 591                 set_bit(BITMAP_STALE, &bitmap->flags);
 592                 err = 0;
 593                 goto out_no_sb;
 594         }
 595         /* page 0 is the superblock, read it... */
 596         sb_page = alloc_page(GFP_KERNEL);
 597         if (!sb_page)
 598                 return -ENOMEM;
 599         bitmap->storage.sb_page = sb_page;
 600
 601 re_read:
 602         /* If cluster_slot is set, the cluster is setup */
 603         if (bitmap->cluster_slot >= 0) {
 604                 sector_t bm_blocks = bitmap->mddev->resync_max_sectors;
 605
 606                 sector_div(bm_blocks,
 607                            bitmap->mddev->bitmap_info.chunksize >> 9);
 608                 /* bits to bytes */
 609                 bm_blocks = ((bm_blocks+7) >> 3) + sizeof(bitmap_super_t);
 610                 /* to 4k blocks */
 611                 bm_blocks = DIV_ROUND_UP_SECTOR_T(bm_blocks, 4096);
 612                 offset = bitmap->mddev->bitmap_info.offset + (bitmap->cluster_slot * (bm_blocks << 3));
 613                 pr_debug("%s:%d bm slot: %d offset: %llu\n", __func__, __LINE__,
 614                         bitmap->cluster_slot, offset);
 615         }
 616
 617         if (bitmap->storage.file) {
 618                 loff_t isize = i_size_read(bitmap->storage.file->f_mapping->host);
 619                 int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
 620
 621                 err = read_page(bitmap->storage.file, 0,
 622                                 bitmap, bytes, sb_page);
 623         } else {
 624                 err = read_sb_page(bitmap->mddev,
 625                                    offset,
 626                                    sb_page,
 627                                    0, sizeof(bitmap_super_t));
 628         }
 629         if (err)
 630                 return err;
 631
 632         err = -EINVAL;
 633         sb = kmap_atomic(sb_page);
 634
 635         chunksize = le32_to_cpu(sb->chunksize);
 636         daemon_sleep = le32_to_cpu(sb->daemon_sleep) * HZ;
 637         write_behind = le32_to_cpu(sb->write_behind);
 638         sectors_reserved = le32_to_cpu(sb->sectors_reserved);
 639         /* Setup nodes/clustername only if bitmap version is
 640          * cluster-compatible
 641          */
 642         if (sb->version == cpu_to_le32(BITMAP_MAJOR_CLUSTERED)) {
 643                 nodes = le32_to_cpu(sb->nodes);
 644                 strlcpy(bitmap->mddev->bitmap_info.cluster_name,
 645                                 sb->cluster_name, 64);
 646         }
 647
 648         /* verify that the bitmap-specific fields are valid */
 649         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
 650                 reason = "bad magic";
 651         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
 652                  le32_to_cpu(sb->version) > BITMAP_MAJOR_CLUSTERED)
 653                 reason = "unrecognized superblock version";
 654         else if (chunksize < 512)
 655                 reason = "bitmap chunksize too small";
 656         else if (!is_power_of_2(chunksize))
 657                 reason = "bitmap chunksize not a power of 2";
 658         else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT)
 659                 reason = "daemon sleep period out of range";
 660         else if (write_behind > COUNTER_MAX)
 661                 reason = "write-behind limit out of range (0 - 16383)";
 662         if (reason) {
 663                 pr_warn("%s: invalid bitmap file superblock: %s\n",
 664                         bmname(bitmap), reason);
 665                 goto out;
 666         }
 667
 668         /* keep the array size field of the bitmap superblock up to date */
 669         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 670
 671         if (bitmap->mddev->persistent) {
 672                 /*
 673                  * We have a persistent array superblock, so compare the
 674                  * bitmap's UUID and event counter to the mddev's
 675                  */
 676                 if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
 677                         pr_warn("%s: bitmap superblock UUID mismatch\n",
 678                                 bmname(bitmap));
 679                         goto out;
 680                 }
 681                 events = le64_to_cpu(sb->events);
 682                 if (!nodes && (events < bitmap->mddev->events)) {
 683                         pr_warn("%s: bitmap file is out of date (%llu < %llu) -- forcing full recovery\n",
 684                                 bmname(bitmap), events,
 685                                 (unsigned long long) bitmap->mddev->events);
 686                         set_bit(BITMAP_STALE, &bitmap->flags);
 687                 }
 688         }
 689
 690         /* assign fields using values from superblock */
 691         bitmap->flags |= le32_to_cpu(sb->state);
 692         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
 693                 set_bit(BITMAP_HOSTENDIAN, &bitmap->flags);
 694         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
 695         strlcpy(bitmap->mddev->bitmap_info.cluster_name, sb->cluster_name, 64);
 696         err = 0;
 697
 698 out:
 699         kunmap_atomic(sb);
 700         /* Assigning chunksize is required for "re_read" */
 701         bitmap->mddev->bitmap_info.chunksize = chunksize;
 702         if (err == 0 && nodes && (bitmap->cluster_slot < 0)) {
 703                 err = md_setup_cluster(bitmap->mddev, nodes);
 704                 if (err) {
 705                         pr_warn("%s: Could not setup cluster service (%d)\n",
 706                                 bmname(bitmap), err);
 707                         goto out_no_sb;
 708                 }
 709                 bitmap->cluster_slot = md_cluster_ops->slot_number(bitmap->mddev);
 710                 goto re_read;
 711         }
 712
 713
 714 out_no_sb:
 715         if (test_bit(BITMAP_STALE, &bitmap->flags))
 716                 bitmap->events_cleared = bitmap->mddev->events;
 717         bitmap->mddev->bitmap_info.chunksize = chunksize;
 718         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 719         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 720         bitmap->mddev->bitmap_info.nodes = nodes;
 721         if (bitmap->mddev->bitmap_info.space == 0 ||
 722             bitmap->mddev->bitmap_info.space > sectors_reserved)
 723                 bitmap->mddev->bitmap_info.space = sectors_reserved;
 724         if (err) {
 725                 bitmap_print_sb(bitmap);
 726                 if (bitmap->cluster_slot < 0)
 727                         md_cluster_stop(bitmap->mddev);
 728         }
 729         return err;
 730 }
 731
 732 /*
 733  * general bitmap file operations
 734  */
 735
 736 /*
 737  * on-disk bitmap:
 738  *
 739  * Use one bit per "chunk" (block set). We do the disk I/O on the bitmap
 740  * file a page at a time. There's a superblock at the start of the file.
 741  */
 742 /* calculate the index of the page that contains this bit */
 743 static inline unsigned long file_page_index(struct bitmap_storage *store,
 744                                             unsigned long chunk)
 745 {
 746         if (store->sb_page)
 747                 chunk += sizeof(bitmap_super_t) << 3;
 748         return chunk >> PAGE_BIT_SHIFT;
 749 }
 750
 751 /* calculate the (bit) offset of this bit within a page */
 752 static inline unsigned long file_page_offset(struct bitmap_storage *store,
 753                                              unsigned long chunk)
 754 {
 755         if (store->sb_page)
 756                 chunk += sizeof(bitmap_super_t) << 3;
 757         return chunk & (PAGE_BITS - 1);
 758 }
 759
 760 /*
 761  * return a pointer to the page in the filemap that contains the given bit
 762  *
 763  */
 764 static inline struct page *filemap_get_page(struct bitmap_storage *store,
 765                                             unsigned long chunk)
 766 {
 767         if (file_page_index(store, chunk) >= store->file_pages)
 768                 return NULL;
 769         return store->filemap[file_page_index(store, chunk)];
 770 }
 771
 772 static int bitmap_storage_alloc(struct bitmap_storage *store,
 773                                 unsigned long chunks, int with_super,
 774                                 int slot_number)
 775 {
 776         int pnum, offset = 0;
 777         unsigned long num_pages;
 778         unsigned long bytes;
 779
 780         bytes = DIV_ROUND_UP(chunks, 8);
 781         if (with_super)
 782                 bytes += sizeof(bitmap_super_t);
 783
 784         num_pages = DIV_ROUND_UP(bytes, PAGE_SIZE);
 785         offset = slot_number * num_pages;
 786
 787         store->filemap = kmalloc(sizeof(struct page *)
 788                                  * num_pages, GFP_KERNEL);
 789         if (!store->filemap)
 790                 return -ENOMEM;
 791
 792         if (with_super && !store->sb_page) {
 793                 store->sb_page = alloc_page(GFP_KERNEL|__GFP_ZERO);
 794                 if (store->sb_page == NULL)
 795                         return -ENOMEM;
 796         }
 797
 798         pnum = 0;
 799         if (store->sb_page) {
 800                 store->filemap[0] = store->sb_page;
 801                 pnum = 1;
 802                 store->sb_page->index = offset;
 803         }
 804
 805         for ( ; pnum < num_pages; pnum++) {
 806                 store->filemap[pnum] = alloc_page(GFP_KERNEL|__GFP_ZERO);
 807                 if (!store->filemap[pnum]) {
 808                         store->file_pages = pnum;
 809                         return -ENOMEM;
 810                 }
 811                 store->filemap[pnum]->index = pnum + offset;
 812         }
 813         store->file_pages = pnum;
 814
 815         /* We need 4 bits per page, rounded up to a multiple
 816          * of sizeof(unsigned long) */
 817         store->filemap_attr = kzalloc(
 818                 roundup(DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
 819                 GFP_KERNEL);
 820         if (!store->filemap_attr)
 821                 return -ENOMEM;
 822
 823         store->bytes = bytes;
 824
 825         return 0;
 826 }
 827
 828 static void bitmap_file_unmap(struct bitmap_storage *store)
 829 {
 830         struct page **map, *sb_page;
 831         int pages;
 832         struct file *file;
 833
 834         file = store->file;
 835         map = store->filemap;
 836         pages = store->file_pages;
 837         sb_page = store->sb_page;
 838
 839         while (pages--)
 840                 if (map[pages] != sb_page) /* 0 is sb_page, release it below */
 841                         free_buffers(map[pages]);
 842         kfree(map);
 843         kfree(store->filemap_attr);
 844
 845         if (sb_page)
 846                 free_buffers(sb_page);
 847
 848         if (file) {
 849                 struct inode *inode = file_inode(file);
 850                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
 851                 fput(file);
 852         }
 853 }
 854
 855 /*
 856  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
 857  * then it is no longer reliable, so we stop using it and we mark the file
 858  * as failed in the superblock
 859  */
 860 static void bitmap_file_kick(struct bitmap *bitmap)
 861 {
 862         char *path, *ptr = NULL;
 863
 864         if (!test_and_set_bit(BITMAP_STALE, &bitmap->flags)) {
 865                 bitmap_update_sb(bitmap);
 866
 867                 if (bitmap->storage.file) {
 868                         path = kmalloc(PAGE_SIZE, GFP_KERNEL);
 869                         if (path)
 870                                 ptr = file_path(bitmap->storage.file,
 871                                              path, PAGE_SIZE);
 872
 873                         pr_warn("%s: kicking failed bitmap file %s from array!\n",
 874                                 bmname(bitmap), IS_ERR(ptr) ? "" : ptr);
 875
 876                         kfree(path);
 877                 } else
 878                         pr_warn("%s: disabling internal bitmap due to errors\n",
 879                                 bmname(bitmap));
 880         }
 881 }
 882
 883 enum bitmap_page_attr {
 884         BITMAP_PAGE_DIRTY = 0,     /* there are set bits that need to be synced */
 885         BITMAP_PAGE_PENDING = 1,   /* there are bits that are being cleaned.
 886                                     * i.e. counter is 1 or 2. */
 887         BITMAP_PAGE_NEEDWRITE = 2, /* there are cleared bits that need to be synced */
 888 };
 889
 890 static inline void set_page_attr(struct bitmap *bitmap, int pnum,
 891                                  enum bitmap_page_attr attr)
 892 {
 893         set_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 894 }
 895
 896 static inline void clear_page_attr(struct bitmap *bitmap, int pnum,
 897                                    enum bitmap_page_attr attr)
 898 {
 899         clear_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 900 }
 901
 902 static inline int test_page_attr(struct bitmap *bitmap, int pnum,
 903                                  enum bitmap_page_attr attr)
 904 {
 905         return test_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 906 }
 907
 908 static inline int test_and_clear_page_attr(struct bitmap *bitmap, int pnum,
 909                                            enum bitmap_page_attr attr)
 910 {
 911         return test_and_clear_bit((pnum<<2) + attr,
 912                                   bitmap->storage.filemap_attr);
 913 }
 914 /*
 915  * bitmap_file_set_bit -- called before performing a write to the md device
 916  * to set (and eventually sync) a particular bit in the bitmap file
 917  *
 918  * we set the bit immediately, then we record the page number so that
 919  * when an unplug occurs, we can flush the dirty pages out to disk
 920  */
 921 static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 922 {
 923         unsigned long bit;
 924         struct page *page;
 925         void *kaddr;
 926         unsigned long chunk = block >> bitmap->counts.chunkshift;
 927         struct bitmap_storage *store = &bitmap->storage;
 928         unsigned long node_offset = 0;
 929
 930         if (mddev_is_clustered(bitmap->mddev))
 931                 node_offset = bitmap->cluster_slot * store->file_pages;
 932
 933         page = filemap_get_page(&bitmap->storage, chunk);
 934         if (!page)
 935                 return;
 936         bit = file_page_offset(&bitmap->storage, chunk);
 937
 938         /* set the bit */
 939         kaddr = kmap_atomic(page);
 940         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
 941                 set_bit(bit, kaddr);
 942         else
 943                 set_bit_le(bit, kaddr);
 944         kunmap_atomic(kaddr);
 945         pr_debug("set file bit %lu page %lu\n", bit, page->index);
 946         /* record page number so it gets flushed to disk when unplug occurs */
 947         set_page_attr(bitmap, page->index - node_offset, BITMAP_PAGE_DIRTY);
 948 }
 949
 950 static void bitmap_file_clear_bit(struct bitmap *bitmap, sector_t block)
 951 {
 952         unsigned long bit;
 953         struct page *page;
 954         void *paddr;
 955         unsigned long chunk = block >> bitmap->counts.chunkshift;
 956         struct bitmap_storage *store = &bitmap->storage;
 957         unsigned long node_offset = 0;
 958
 959         if (mddev_is_clustered(bitmap->mddev))
 960                 node_offset = bitmap->cluster_slot * store->file_pages;
 961
 962         page = filemap_get_page(&bitmap->storage, chunk);
 963         if (!page)
 964                 return;
 965         bit = file_page_offset(&bitmap->storage, chunk);
 966         paddr = kmap_atomic(page);
 967         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
 968                 clear_bit(bit, paddr);
 969         else
 970                 clear_bit_le(bit, paddr);
 971         kunmap_atomic(paddr);
 972         if (!test_page_attr(bitmap, page->index - node_offset, BITMAP_PAGE_NEEDWRITE)) {
 973                 set_page_attr(bitmap, page->index - node_offset, BITMAP_PAGE_PENDING);
 974                 bitmap->allclean = 0;
 975         }
 976 }
 977
 978 static int bitmap_file_test_bit(struct bitmap *bitmap, sector_t block)
 979 {
 980         unsigned long bit;
 981         struct page *page;
 982         void *paddr;
 983         unsigned long chunk = block >> bitmap->counts.chunkshift;
 984         int set = 0;
 985
 986         page = filemap_get_page(&bitmap->storage, chunk);
 987         if (!page)
 988                 return -EINVAL;
 989         bit = file_page_offset(&bitmap->storage, chunk);
 990         paddr = kmap_atomic(page);
 991         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
 992                 set = test_bit(bit, paddr);
 993         else
 994                 set = test_bit_le(bit, paddr);
 995         kunmap_atomic(paddr);
 996         return set;
 997 }
 998
 999
1000 /* this gets called when the md device is ready to unplug its underlying
1001  * (slave) device queues -- before we let any writes go down, we need to
1002  * sync the dirty pages of the bitmap file to disk */
1003 void bitmap_unplug(struct bitmap *bitmap)
1004 {
1005         unsigned long i;
1006         int dirty, need_write;
1007         int writing = 0;
1008
1009         if (!bitmap || !bitmap->storage.filemap ||
1010             test_bit(BITMAP_STALE, &bitmap->flags))
1011                 return;
1012
1013         /* look at each page to see if there are any set bits that need to be
1014          * flushed out to disk */
1015         for (i = 0; i < bitmap->storage.file_pages; i++) {
1016                 if (!bitmap->storage.filemap)
1017                         return;
1018                 dirty = test_and_clear_page_attr(bitmap, i, BITMAP_PAGE_DIRTY);
1019                 need_write = test_and_clear_page_attr(bitmap, i,
1020                                                       BITMAP_PAGE_NEEDWRITE);
1021                 if (dirty || need_write) {
1022                         if (!writing) {
1023                                 bitmap_wait_writes(bitmap);
1024                                 if (bitmap->mddev->queue)
1025                                         blk_add_trace_msg(bitmap->mddev->queue,
1026                                                           "md bitmap_unplug");
1027                         }
1028                         clear_page_attr(bitmap, i, BITMAP_PAGE_PENDING);
1029                         write_page(bitmap, bitmap->storage.filemap[i], 0);
1030                         writing = 1;
1031                 }
1032         }
1033         if (writing)
1034                 bitmap_wait_writes(bitmap);
1035
1036         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
1037                 bitmap_file_kick(bitmap);
1038 }
1039 EXPORT_SYMBOL(bitmap_unplug);
1040
1041 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
1042 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
1043  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
1044  * memory mapping of the bitmap file
1045  * Special cases:
1046  *   if there's no bitmap file, or if the bitmap file had been
1047  *   previously kicked from the array, we mark all the bits as
1048  *   1's in order to cause a full resync.
1049  *
1050  * We ignore all bits for sectors that end earlier than 'start'.
1051  * This is used when reading an out-of-date bitmap...
1052  */
1053 static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
1054 {
1055         unsigned long i, chunks, index, oldindex, bit, node_offset = 0;
1056         struct page *page = NULL;
1057         unsigned long bit_cnt = 0;
1058         struct file *file;
1059         unsigned long offset;
1060         int outofdate;
1061         int ret = -ENOSPC;
1062         void *paddr;
1063         struct bitmap_storage *store = &bitmap->storage;
1064
1065         chunks = bitmap->counts.chunks;
1066         file = store->file;
1067
1068         if (!file && !bitmap->mddev->bitmap_info.offset) {
1069                 /* No permanent bitmap - fill with '1s'. */
1070                 store->filemap = NULL;
1071                 store->file_pages = 0;
1072                 for (i = 0; i < chunks ; i++) {
1073                         /* if the disk bit is set, set the memory bit */
1074                         int needed = ((sector_t)(i+1) << (bitmap->counts.chunkshift)
1075                                       >= start);
1076                         bitmap_set_memory_bits(bitmap,
1077                                                (sector_t)i << bitmap->counts.chunkshift,
1078                                                needed);
1079                 }
1080                 return 0;
1081         }
1082
1083         outofdate = test_bit(BITMAP_STALE, &bitmap->flags);
1084         if (outofdate)
1085                 pr_warn("%s: bitmap file is out of date, doing full recovery\n", bmname(bitmap));
1086
1087         if (file && i_size_read(file->f_mapping->host) < store->bytes) {
1088                 pr_warn("%s: bitmap file too short %lu < %lu\n",
1089                         bmname(bitmap),
1090                         (unsigned long) i_size_read(file->f_mapping->host),
1091                         store->bytes);
1092                 goto err;
1093         }
1094
1095         oldindex = ~0L;
1096         offset = 0;
1097         if (!bitmap->mddev->bitmap_info.external)
1098                 offset = sizeof(bitmap_super_t);
1099
1100         if (mddev_is_clustered(bitmap->mddev))
1101                 node_offset = bitmap->cluster_slot * (DIV_ROUND_UP(store->bytes, PAGE_SIZE));
1102
1103         for (i = 0; i < chunks; i++) {
1104                 int b;
1105                 index = file_page_index(&bitmap->storage, i);
1106                 bit = file_page_offset(&bitmap->storage, i);
1107                 if (index != oldindex) { /* this is a new page, read it in */
1108                         int count;
1109                         /* unmap the old page, we're done with it */
1110                         if (index == store->file_pages-1)
1111                                 count = store->bytes - index * PAGE_SIZE;
1112                         else
1113                                 count = PAGE_SIZE;
1114                         page = store->filemap[index];
1115                         if (file)
1116                                 ret = read_page(file, index, bitmap,
1117                                                 count, page);
1118                         else
1119                                 ret = read_sb_page(
1120                                         bitmap->mddev,
1121                                         bitmap->mddev->bitmap_info.offset,
1122                                         page,
1123                                         index + node_offset, count);
1124
1125                         if (ret)
1126                                 goto err;
1127
1128                         oldindex = index;
1129
1130                         if (outofdate) {
1131                                 /*
1132                                  * if bitmap is out of date, dirty the
1133                                  * whole page and write it out
1134                                  */
1135                                 paddr = kmap_atomic(page);
1136                                 memset(paddr + offset, 0xff,
1137                                        PAGE_SIZE - offset);
1138                                 kunmap_atomic(paddr);
1139                                 write_page(bitmap, page, 1);
1140
1141                                 ret = -EIO;
1142                                 if (test_bit(BITMAP_WRITE_ERROR,
1143                                              &bitmap->flags))
1144                                         goto err;
1145                         }
1146                 }
1147                 paddr = kmap_atomic(page);
1148                 if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
1149                         b = test_bit(bit, paddr);
1150                 else
1151                         b = test_bit_le(bit, paddr);
1152                 kunmap_atomic(paddr);
1153                 if (b) {
1154                         /* if the disk bit is set, set the memory bit */
1155                         int needed = ((sector_t)(i+1) << bitmap->counts.chunkshift
1156                                       >= start);
1157                         bitmap_set_memory_bits(bitmap,
1158                                                (sector_t)i << bitmap->counts.chunkshift,
1159                                                needed);
1160                         bit_cnt++;
1161                 }
1162                 offset = 0;
1163         }
1164
1165         pr_debug("%s: bitmap initialized from disk: read %lu pages, set %lu of %lu bits\n",
1166                  bmname(bitmap), store->file_pages,
1167                  bit_cnt, chunks);
1168
1169         return 0;
1170
1171  err:
1172         pr_warn("%s: bitmap initialisation failed: %d\n",
1173                 bmname(bitmap), ret);
1174         return ret;
1175 }
1176
1177 void bitmap_write_all(struct bitmap *bitmap)
1178 {
1179         /* We don't actually write all bitmap blocks here,
1180          * just flag them as needing to be written
1181          */
1182         int i;
1183
1184         if (!bitmap || !bitmap->storage.filemap)
1185                 return;
1186         if (bitmap->storage.file)
1187                 /* Only one copy, so nothing needed */
1188                 return;
1189
1190         for (i = 0; i < bitmap->storage.file_pages; i++)
1191                 set_page_attr(bitmap, i,
1192                               BITMAP_PAGE_NEEDWRITE);
1193         bitmap->allclean = 0;
1194 }
1195
1196 static void bitmap_count_page(struct bitmap_counts *bitmap,
1197                               sector_t offset, int inc)
1198 {
1199         sector_t chunk = offset >> bitmap->chunkshift;
1200         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1201         bitmap->bp[page].count += inc;
1202         bitmap_checkfree(bitmap, page);
1203 }
1204
1205 static void bitmap_set_pending(struct bitmap_counts *bitmap, sector_t offset)
1206 {
1207         sector_t chunk = offset >> bitmap->chunkshift;
1208         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1209         struct bitmap_page *bp = &bitmap->bp[page];
1210
1211         if (!bp->pending)
1212                 bp->pending = 1;
1213 }
1214
1215 static bitmap_counter_t *bitmap_get_counter(struct bitmap_counts *bitmap,
1216                                             sector_t offset, sector_t *blocks,
1217                                             int create);
1218
1219 /*
1220  * bitmap daemon -- periodically wakes up to clean bits and flush pages
1221  *                      out to disk
1222  */
1223
1224 void bitmap_daemon_work(struct mddev *mddev)
1225 {
1226         struct bitmap *bitmap;
1227         unsigned long j;
1228         unsigned long nextpage;
1229         sector_t blocks;
1230         struct bitmap_counts *counts;
1231
1232         /* Use a mutex to guard daemon_work against
1233          * bitmap_destroy.
1234          */
1235         mutex_lock(&mddev->bitmap_info.mutex);
1236         bitmap = mddev->bitmap;
1237         if (bitmap == NULL) {
1238                 mutex_unlock(&mddev->bitmap_info.mutex);
1239                 return;
1240         }
1241         if (time_before(jiffies, bitmap->daemon_lastrun
1242                         + mddev->bitmap_info.daemon_sleep))
1243                 goto done;
1244
1245         bitmap->daemon_lastrun = jiffies;
1246         if (bitmap->allclean) {
1247                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1248                 goto done;
1249         }
1250         bitmap->allclean = 1;
1251
1252         if (bitmap->mddev->queue)
1253                 blk_add_trace_msg(bitmap->mddev->queue,
1254                                   "md bitmap_daemon_work");
1255
1256         /* Any file-page which is PENDING now needs to be written.
1257          * So set NEEDWRITE now, then after we make any last-minute changes
1258          * we will write it.
1259          */
1260         for (j = 0; j < bitmap->storage.file_pages; j++)
1261                 if (test_and_clear_page_attr(bitmap, j,
1262                                              BITMAP_PAGE_PENDING))
1263                         set_page_attr(bitmap, j,
1264                                       BITMAP_PAGE_NEEDWRITE);
1265
1266         if (bitmap->need_sync &&
1267             mddev->bitmap_info.external == 0) {
1268                 /* Arrange for superblock update as well as
1269                  * other changes */
1270                 bitmap_super_t *sb;
1271                 bitmap->need_sync = 0;
1272                 if (bitmap->storage.filemap) {
1273                         sb = kmap_atomic(bitmap->storage.sb_page);
1274                         sb->events_cleared =
1275                                 cpu_to_le64(bitmap->events_cleared);
1276                         kunmap_atomic(sb);
1277                         set_page_attr(bitmap, 0,
1278                                       BITMAP_PAGE_NEEDWRITE);
1279                 }
1280         }
1281         /* Now look at the bitmap counters and if any are '2' or '1',
1282          * decrement and handle accordingly.
1283          */
1284         counts = &bitmap->counts;
1285         spin_lock_irq(&counts->lock);
1286         nextpage = 0;
1287         for (j = 0; j < counts->chunks; j++) {
1288                 bitmap_counter_t *bmc;
1289                 sector_t  block = (sector_t)j << counts->chunkshift;
1290
1291                 if (j == nextpage) {
1292                         nextpage += PAGE_COUNTER_RATIO;
1293                         if (!counts->bp[j >> PAGE_COUNTER_SHIFT].pending) {
1294                                 j |= PAGE_COUNTER_MASK;
1295                                 continue;
1296                         }
1297                         counts->bp[j >> PAGE_COUNTER_SHIFT].pending = 0;
1298                 }
1299                 bmc = bitmap_get_counter(counts,
1300                                          block,
1301                                          &blocks, 0);
1302
1303                 if (!bmc) {
1304                         j |= PAGE_COUNTER_MASK;
1305                         continue;
1306                 }
1307                 if (*bmc == 1 && !bitmap->need_sync) {
1308                         /* We can clear the bit */
1309                         *bmc = 0;
1310                         bitmap_count_page(counts, block, -1);
1311                         bitmap_file_clear_bit(bitmap, block);
1312                 } else if (*bmc && *bmc <= 2) {
1313                         *bmc = 1;
1314                         bitmap_set_pending(counts, block);
1315                         bitmap->allclean = 0;
1316                 }
1317         }
1318         spin_unlock_irq(&counts->lock);
1319
1320         bitmap_wait_writes(bitmap);
1321         /* Now start writeout on any page in NEEDWRITE that isn't DIRTY.
1322          * DIRTY pages need to be written by bitmap_unplug so it can wait
1323          * for them.
1324          * If we find any DIRTY page we stop there and let bitmap_unplug
1325          * handle all the rest.  This is important in the case where
1326          * the first blocking holds the superblock and it has been updated.
1327          * We mustn't write any other blocks before the superblock.
1328          */
1329         for (j = 0;
1330              j < bitmap->storage.file_pages
1331                      && !test_bit(BITMAP_STALE, &bitmap->flags);
1332              j++) {
1333                 if (test_page_attr(bitmap, j,
1334                                    BITMAP_PAGE_DIRTY))
1335                         /* bitmap_unplug will handle the rest */
1336                         break;
1337                 if (test_and_clear_page_attr(bitmap, j,
1338                                              BITMAP_PAGE_NEEDWRITE)) {
1339                         write_page(bitmap, bitmap->storage.filemap[j], 0);
1340                 }
1341         }
1342
1343  done:
1344         if (bitmap->allclean == 0)
1345                 mddev->thread->timeout =
1346                         mddev->bitmap_info.daemon_sleep;
1347         mutex_unlock(&mddev->bitmap_info.mutex);
1348 }
1349
1350 static bitmap_counter_t *bitmap_get_counter(struct bitmap_counts *bitmap,
1351                                             sector_t offset, sector_t *blocks,
1352                                             int create)
1353 __releases(bitmap->lock)
1354 __acquires(bitmap->lock)
1355 {
1356         /* If 'create', we might release the lock and reclaim it.
1357          * The lock must have been taken with interrupts enabled.
1358          * If !create, we don't release the lock.
1359          */
1360         sector_t chunk = offset >> bitmap->chunkshift;
1361         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1362         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1363         sector_t csize;
1364         int err;
1365
1366         err = bitmap_checkpage(bitmap, page, create, 0);
1367
1368         if (bitmap->bp[page].hijacked ||
1369             bitmap->bp[page].map == NULL)
1370                 csize = ((sector_t)1) << (bitmap->chunkshift +
1371                                           PAGE_COUNTER_SHIFT - 1);
1372         else
1373                 csize = ((sector_t)1) << bitmap->chunkshift;
1374         *blocks = csize - (offset & (csize - 1));
1375
1376         if (err < 0)
1377                 return NULL;
1378
1379         /* now locked ... */
1380
1381         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1382                 /* should we use the first or second counter field
1383                  * of the hijacked pointer? */
1384                 int hi = (pageoff > PAGE_COUNTER_MASK);
1385                 return  &((bitmap_counter_t *)
1386                           &bitmap->bp[page].map)[hi];
1387         } else /* page is allocated */
1388                 return (bitmap_counter_t *)
1389                         &(bitmap->bp[page].map[pageoff]);
1390 }
1391
1392 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1393 {
1394         if (!bitmap)
1395                 return 0;
1396
1397         if (behind) {
1398                 int bw;
1399                 atomic_inc(&bitmap->behind_writes);
1400                 bw = atomic_read(&bitmap->behind_writes);
1401                 if (bw > bitmap->behind_writes_used)
1402                         bitmap->behind_writes_used = bw;
1403
1404                 pr_debug("inc write-behind count %d/%lu\n",
1405                          bw, bitmap->mddev->bitmap_info.max_write_behind);
1406         }
1407
1408         while (sectors) {
1409                 sector_t blocks;
1410                 bitmap_counter_t *bmc;
1411
1412                 spin_lock_irq(&bitmap->counts.lock);
1413                 bmc = bitmap_get_counter(&bitmap->counts, offset, &blocks, 1);
1414                 if (!bmc) {
1415                         spin_unlock_irq(&bitmap->counts.lock);
1416                         return 0;
1417                 }
1418
1419                 if (unlikely(COUNTER(*bmc) == COUNTER_MAX)) {
1420                         DEFINE_WAIT(__wait);
1421                         /* note that it is safe to do the prepare_to_wait
1422                          * after the test as long as we do it before dropping
1423                          * the spinlock.
1424                          */
1425                         prepare_to_wait(&bitmap->overflow_wait, &__wait,
1426                                         TASK_UNINTERRUPTIBLE);
1427                         spin_unlock_irq(&bitmap->counts.lock);
1428                         schedule();
1429                         finish_wait(&bitmap->overflow_wait, &__wait);
1430                         continue;
1431                 }
1432
1433                 switch (*bmc) {
1434                 case 0:
1435                         bitmap_file_set_bit(bitmap, offset);
1436                         bitmap_count_page(&bitmap->counts, offset, 1);
1437                         /* fall through */
1438                 case 1:
1439                         *bmc = 2;
1440                 }
1441
1442                 (*bmc)++;
1443
1444                 spin_unlock_irq(&bitmap->counts.lock);
1445
1446                 offset += blocks;
1447                 if (sectors > blocks)
1448                         sectors -= blocks;
1449                 else
1450                         sectors = 0;
1451         }
1452         return 0;
1453 }
1454 EXPORT_SYMBOL(bitmap_startwrite);
1455
1456 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1457                      int success, int behind)
1458 {
1459         if (!bitmap)
1460                 return;
1461         if (behind) {
1462                 if (atomic_dec_and_test(&bitmap->behind_writes))
1463                         wake_up(&bitmap->behind_wait);
1464                 pr_debug("dec write-behind count %d/%lu\n",
1465                          atomic_read(&bitmap->behind_writes),
1466                          bitmap->mddev->bitmap_info.max_write_behind);
1467         }
1468
1469         while (sectors) {
1470                 sector_t blocks;
1471                 unsigned long flags;
1472                 bitmap_counter_t *bmc;
1473
1474                 spin_lock_irqsave(&bitmap->counts.lock, flags);
1475                 bmc = bitmap_get_counter(&bitmap->counts, offset, &blocks, 0);
1476                 if (!bmc) {
1477                         spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1478                         return;
1479                 }
1480
1481                 if (success && !bitmap->mddev->degraded &&
1482                     bitmap->events_cleared < bitmap->mddev->events) {
1483                         bitmap->events_cleared = bitmap->mddev->events;
1484                         bitmap->need_sync = 1;
1485                         sysfs_notify_dirent_safe(bitmap->sysfs_can_clear);
1486                 }
1487
1488                 if (!success && !NEEDED(*bmc))
1489                         *bmc |= NEEDED_MASK;
1490
1491                 if (COUNTER(*bmc) == COUNTER_MAX)
1492                         wake_up(&bitmap->overflow_wait);
1493
1494                 (*bmc)--;
1495                 if (*bmc <= 2) {
1496                         bitmap_set_pending(&bitmap->counts, offset);
1497                         bitmap->allclean = 0;
1498                 }
1499                 spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1500                 offset += blocks;
1501                 if (sectors > blocks)
1502                         sectors -= blocks;
1503                 else
1504                         sectors = 0;
1505         }
1506 }
1507 EXPORT_SYMBOL(bitmap_endwrite);
1508
1509 static int __bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1510                                int degraded)
1511 {
1512         bitmap_counter_t *bmc;
1513         int rv;
1514         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1515                 *blocks = 1024;
1516                 return 1; /* always resync if no bitmap */
1517         }
1518         spin_lock_irq(&bitmap->counts.lock);
1519         bmc = bitmap_get_counter(&bitmap->counts, offset, blocks, 0);
1520         rv = 0;
1521         if (bmc) {
1522                 /* locked */
1523                 if (RESYNC(*bmc))
1524                         rv = 1;
1525                 else if (NEEDED(*bmc)) {
1526                         rv = 1;
1527                         if (!degraded) { /* don't set/clear bits if degraded */
1528                                 *bmc |= RESYNC_MASK;
1529                                 *bmc &= ~NEEDED_MASK;
1530                         }
1531                 }
1532         }
1533         spin_unlock_irq(&bitmap->counts.lock);
1534         return rv;
1535 }
1536
1537 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1538                       int degraded)
1539 {
1540         /* bitmap_start_sync must always report on multiples of whole
1541          * pages, otherwise resync (which is very PAGE_SIZE based) will
1542          * get confused.
1543          * So call __bitmap_start_sync repeatedly (if needed) until
1544          * At least PAGE_SIZE>>9 blocks are covered.
1545          * Return the 'or' of the result.
1546          */
1547         int rv = 0;
1548         sector_t blocks1;
1549
1550         *blocks = 0;
1551         while (*blocks < (PAGE_SIZE>>9)) {
1552                 rv |= __bitmap_start_sync(bitmap, offset,
1553                                           &blocks1, degraded);
1554                 offset += blocks1;
1555                 *blocks += blocks1;
1556         }
1557         return rv;
1558 }
1559 EXPORT_SYMBOL(bitmap_start_sync);
1560
1561 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks, int aborted)
1562 {
1563         bitmap_counter_t *bmc;
1564         unsigned long flags;
1565
1566         if (bitmap == NULL) {
1567                 *blocks = 1024;
1568                 return;
1569         }
1570         spin_lock_irqsave(&bitmap->counts.lock, flags);
1571         bmc = bitmap_get_counter(&bitmap->counts, offset, blocks, 0);
1572         if (bmc == NULL)
1573                 goto unlock;
1574         /* locked */
1575         if (RESYNC(*bmc)) {
1576                 *bmc &= ~RESYNC_MASK;
1577
1578                 if (!NEEDED(*bmc) && aborted)
1579                         *bmc |= NEEDED_MASK;
1580                 else {
1581                         if (*bmc <= 2) {
1582                                 bitmap_set_pending(&bitmap->counts, offset);
1583                                 bitmap->allclean = 0;
1584                         }
1585                 }
1586         }
1587  unlock:
1588         spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1589 }
1590 EXPORT_SYMBOL(bitmap_end_sync);
1591
1592 void bitmap_close_sync(struct bitmap *bitmap)
1593 {
1594         /* Sync has finished, and any bitmap chunks that weren't synced
1595          * properly have been aborted.  It remains to us to clear the
1596          * RESYNC bit wherever it is still on
1597          */
1598         sector_t sector = 0;
1599         sector_t blocks;
1600         if (!bitmap)
1601                 return;
1602         while (sector < bitmap->mddev->resync_max_sectors) {
1603                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1604                 sector += blocks;
1605         }
1606 }
1607 EXPORT_SYMBOL(bitmap_close_sync);
1608
1609 void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector, bool force)
1610 {
1611         sector_t s = 0;
1612         sector_t blocks;
1613
1614         if (!bitmap)
1615                 return;
1616         if (sector == 0) {
1617                 bitmap->last_end_sync = jiffies;
1618                 return;
1619         }
1620         if (!force && time_before(jiffies, (bitmap->last_end_sync
1621                                   + bitmap->mddev->bitmap_info.daemon_sleep)))
1622                 return;
1623         wait_event(bitmap->mddev->recovery_wait,
1624                    atomic_read(&bitmap->mddev->recovery_active) == 0);
1625
1626         bitmap->mddev->curr_resync_completed = sector;
1627         set_bit(MD_SB_CHANGE_CLEAN, &bitmap->mddev->sb_flags);
1628         sector &= ~((1ULL << bitmap->counts.chunkshift) - 1);
1629         s = 0;
1630         while (s < sector && s < bitmap->mddev->resync_max_sectors) {
1631                 bitmap_end_sync(bitmap, s, &blocks, 0);
1632                 s += blocks;
1633         }
1634         bitmap->last_end_sync = jiffies;
1635         sysfs_notify(&bitmap->mddev->kobj, NULL, "sync_completed");
1636 }
1637 EXPORT_SYMBOL(bitmap_cond_end_sync);
1638
1639 void bitmap_sync_with_cluster(struct mddev *mddev,
1640                               sector_t old_lo, sector_t old_hi,
1641                               sector_t new_lo, sector_t new_hi)
1642 {
1643         struct bitmap *bitmap = mddev->bitmap;
1644         sector_t sector, blocks = 0;
1645
1646         for (sector = old_lo; sector < new_lo; ) {
1647                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1648                 sector += blocks;
1649         }
1650         WARN((blocks > new_lo) && old_lo, "alignment is not correct for lo\n");
1651
1652         for (sector = old_hi; sector < new_hi; ) {
1653                 bitmap_start_sync(bitmap, sector, &blocks, 0);
1654                 sector += blocks;
1655         }
1656         WARN((blocks > new_hi) && old_hi, "alignment is not correct for hi\n");
1657 }
1658 EXPORT_SYMBOL(bitmap_sync_with_cluster);
1659
1660 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1661 {
1662         /* For each chunk covered by any of these sectors, set the
1663          * counter to 2 and possibly set resync_needed.  They should all
1664          * be 0 at this point
1665          */
1666
1667         sector_t secs;
1668         bitmap_counter_t *bmc;
1669         spin_lock_irq(&bitmap->counts.lock);
1670         bmc = bitmap_get_counter(&bitmap->counts, offset, &secs, 1);
1671         if (!bmc) {
1672                 spin_unlock_irq(&bitmap->counts.lock);
1673                 return;
1674         }
1675         if (!*bmc) {
1676                 *bmc = 2;
1677                 bitmap_count_page(&bitmap->counts, offset, 1);
1678                 bitmap_set_pending(&bitmap->counts, offset);
1679                 bitmap->allclean = 0;
1680         }
1681         if (needed)
1682                 *bmc |= NEEDED_MASK;
1683         spin_unlock_irq(&bitmap->counts.lock);
1684 }
1685
1686 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
1687 void bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1688 {
1689         unsigned long chunk;
1690
1691         for (chunk = s; chunk <= e; chunk++) {
1692                 sector_t sec = (sector_t)chunk << bitmap->counts.chunkshift;
1693                 bitmap_set_memory_bits(bitmap, sec, 1);
1694                 bitmap_file_set_bit(bitmap, sec);
1695                 if (sec < bitmap->mddev->recovery_cp)
1696                         /* We are asserting that the array is dirty,
1697                          * so move the recovery_cp address back so
1698                          * that it is obvious that it is dirty
1699                          */
1700                         bitmap->mddev->recovery_cp = sec;
1701         }
1702 }
1703
1704 /*
1705  * flush out any pending updates
1706  */
1707 void bitmap_flush(struct mddev *mddev)
1708 {
1709         struct bitmap *bitmap = mddev->bitmap;
1710         long sleep;
1711
1712         if (!bitmap) /* there was no bitmap */
1713                 return;
1714
1715         /* run the daemon_work three time to ensure everything is flushed
1716          * that can be
1717          */
1718         sleep = mddev->bitmap_info.daemon_sleep * 2;
1719         bitmap->daemon_lastrun -= sleep;
1720         bitmap_daemon_work(mddev);
1721         bitmap->daemon_lastrun -= sleep;
1722         bitmap_daemon_work(mddev);
1723         bitmap->daemon_lastrun -= sleep;
1724         bitmap_daemon_work(mddev);
1725         bitmap_update_sb(bitmap);
1726 }
1727
1728 /*
1729  * free memory that was allocated
1730  */
1731 void bitmap_free(struct bitmap *bitmap)
1732 {
1733         unsigned long k, pages;
1734         struct bitmap_page *bp;
1735
1736         if (!bitmap) /* there was no bitmap */
1737                 return;
1738
1739         if (bitmap->sysfs_can_clear)
1740                 sysfs_put(bitmap->sysfs_can_clear);
1741
1742         if (mddev_is_clustered(bitmap->mddev) && bitmap->mddev->cluster_info &&
1743                 bitmap->cluster_slot == md_cluster_ops->slot_number(bitmap->mddev))
1744                 md_cluster_stop(bitmap->mddev);
1745
1746         /* Shouldn't be needed - but just in case.... */
1747         wait_event(bitmap->write_wait,
1748                    atomic_read(&bitmap->pending_writes) == 0);
1749
1750         /* release the bitmap file  */
1751         bitmap_file_unmap(&bitmap->storage);
1752
1753         bp = bitmap->counts.bp;
1754         pages = bitmap->counts.pages;
1755
1756         /* free all allocated memory */
1757
1758         if (bp) /* deallocate the page memory */
1759                 for (k = 0; k < pages; k++)
1760                         if (bp[k].map && !bp[k].hijacked)
1761                                 kfree(bp[k].map);
1762         kfree(bp);
1763         kfree(bitmap);
1764 }
1765 EXPORT_SYMBOL(bitmap_free);
1766
1767 void bitmap_wait_behind_writes(struct mddev *mddev)
1768 {
1769         struct bitmap *bitmap = mddev->bitmap;
1770
1771         /* wait for behind writes to complete */
1772         if (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
1773                 pr_debug("md:%s: behind writes in progress - waiting to stop.\n",
1774                          mdname(mddev));
1775                 /* need to kick something here to make sure I/O goes? */
1776                 wait_event(bitmap->behind_wait,
1777                            atomic_read(&bitmap->behind_writes) == 0);
1778         }
1779 }
1780
1781 void bitmap_destroy(struct mddev *mddev)
1782 {
1783         struct bitmap *bitmap = mddev->bitmap;
1784
1785         if (!bitmap) /* there was no bitmap */
1786                 return;
1787
1788         bitmap_wait_behind_writes(mddev);
1789
1790         mutex_lock(&mddev->bitmap_info.mutex);
1791         spin_lock(&mddev->lock);
1792         mddev->bitmap = NULL; /* disconnect from the md device */
1793         spin_unlock(&mddev->lock);
1794         mutex_unlock(&mddev->bitmap_info.mutex);
1795         if (mddev->thread)
1796                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1797
1798         bitmap_free(bitmap);
1799 }
1800
1801 /*
1802  * initialize the bitmap structure
1803  * if this returns an error, bitmap_destroy must be called to do clean up
1804  * once mddev->bitmap is set
1805  */
1806 struct bitmap *bitmap_create(struct mddev *mddev, int slot)
1807 {
1808         struct bitmap *bitmap;
1809         sector_t blocks = mddev->resync_max_sectors;
1810         struct file *file = mddev->bitmap_info.file;
1811         int err;
1812         struct kernfs_node *bm = NULL;
1813
1814         BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
1815
1816         BUG_ON(file && mddev->bitmap_info.offset);
1817
1818         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1819         if (!bitmap)
1820                 return ERR_PTR(-ENOMEM);
1821
1822         spin_lock_init(&bitmap->counts.lock);
1823         atomic_set(&bitmap->pending_writes, 0);
1824         init_waitqueue_head(&bitmap->write_wait);
1825         init_waitqueue_head(&bitmap->overflow_wait);
1826         init_waitqueue_head(&bitmap->behind_wait);
1827
1828         bitmap->mddev = mddev;
1829         bitmap->cluster_slot = slot;
1830
1831         if (mddev->kobj.sd)
1832                 bm = sysfs_get_dirent(mddev->kobj.sd, "bitmap");
1833         if (bm) {
1834                 bitmap->sysfs_can_clear = sysfs_get_dirent(bm, "can_clear");
1835                 sysfs_put(bm);
1836         } else
1837                 bitmap->sysfs_can_clear = NULL;
1838
1839         bitmap->storage.file = file;
1840         if (file) {
1841                 get_file(file);
1842                 /* As future accesses to this file will use bmap,
1843                  * and bypass the page cache, we must sync the file
1844                  * first.
1845                  */
1846                 vfs_fsync(file, 1);
1847         }
1848         /* read superblock from bitmap file (this sets mddev->bitmap_info.chunksize) */
1849         if (!mddev->bitmap_info.external) {
1850                 /*
1851                  * If 'MD_ARRAY_FIRST_USE' is set, then device-mapper is
1852                  * instructing us to create a new on-disk bitmap instance.
1853                  */
1854                 if (test_and_clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags))
1855                         err = bitmap_new_disk_sb(bitmap);
1856                 else
1857                         err = bitmap_read_sb(bitmap);
1858         } else {
1859                 err = 0;
1860                 if (mddev->bitmap_info.chunksize == 0 ||
1861                     mddev->bitmap_info.daemon_sleep == 0)
1862                         /* chunksize and time_base need to be
1863                          * set first. */
1864                         err = -EINVAL;
1865         }
1866         if (err)
1867                 goto error;
1868
1869         bitmap->daemon_lastrun = jiffies;
1870         err = bitmap_resize(bitmap, blocks, mddev->bitmap_info.chunksize, 1);
1871         if (err)
1872                 goto error;
1873
1874         pr_debug("created bitmap (%lu pages) for device %s\n",
1875                  bitmap->counts.pages, bmname(bitmap));
1876
1877         err = test_bit(BITMAP_WRITE_ERROR, &bitmap->flags) ? -EIO : 0;
1878         if (err)
1879                 goto error;
1880
1881         return bitmap;
1882  error:
1883         bitmap_free(bitmap);
1884         return ERR_PTR(err);
1885 }
1886
1887 int bitmap_load(struct mddev *mddev)
1888 {
1889         int err = 0;
1890         sector_t start = 0;
1891         sector_t sector = 0;
1892         struct bitmap *bitmap = mddev->bitmap;
1893
1894         if (!bitmap)
1895                 goto out;
1896
1897         if (mddev_is_clustered(mddev))
1898                 md_cluster_ops->load_bitmaps(mddev, mddev->bitmap_info.nodes);
1899
1900         /* Clear out old bitmap info first:  Either there is none, or we
1901          * are resuming after someone else has possibly changed things,
1902          * so we should forget old cached info.
1903          * All chunks should be clean, but some might need_sync.
1904          */
1905         while (sector < mddev->resync_max_sectors) {
1906                 sector_t blocks;
1907                 bitmap_start_sync(bitmap, sector, &blocks, 0);
1908                 sector += blocks;
1909         }
1910         bitmap_close_sync(bitmap);
1911
1912         if (mddev->degraded == 0
1913             || bitmap->events_cleared == mddev->events)
1914                 /* no need to keep dirty bits to optimise a
1915                  * re-add of a missing device */
1916                 start = mddev->recovery_cp;
1917
1918         mutex_lock(&mddev->bitmap_info.mutex);
1919         err = bitmap_init_from_disk(bitmap, start);
1920         mutex_unlock(&mddev->bitmap_info.mutex);
1921
1922         if (err)
1923                 goto out;
1924         clear_bit(BITMAP_STALE, &bitmap->flags);
1925
1926         /* Kick recovery in case any bits were set */
1927         set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
1928
1929         mddev->thread->timeout = mddev->bitmap_info.daemon_sleep;
1930         md_wakeup_thread(mddev->thread);
1931
1932         bitmap_update_sb(bitmap);
1933
1934         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
1935                 err = -EIO;
1936 out:
1937         return err;
1938 }
1939 EXPORT_SYMBOL_GPL(bitmap_load);
1940
1941 struct bitmap *get_bitmap_from_slot(struct mddev *mddev, int slot)
1942 {
1943         int rv = 0;
1944         struct bitmap *bitmap;
1945
1946         bitmap = bitmap_create(mddev, slot);
1947         if (IS_ERR(bitmap)) {
1948                 rv = PTR_ERR(bitmap);
1949                 return ERR_PTR(rv);
1950         }
1951
1952         rv = bitmap_init_from_disk(bitmap, 0);
1953         if (rv) {
1954                 bitmap_free(bitmap);
1955                 return ERR_PTR(rv);
1956         }
1957
1958         return bitmap;
1959 }
1960 EXPORT_SYMBOL(get_bitmap_from_slot);
1961
1962 /* Loads the bitmap associated with slot and copies the resync information
1963  * to our bitmap
1964  */
1965 int bitmap_copy_from_slot(struct mddev *mddev, int slot,
1966                 sector_t *low, sector_t *high, bool clear_bits)
1967 {
1968         int rv = 0, i, j;
1969         sector_t block, lo = 0, hi = 0;
1970         struct bitmap_counts *counts;
1971         struct bitmap *bitmap;
1972
1973         bitmap = get_bitmap_from_slot(mddev, slot);
1974         if (IS_ERR(bitmap)) {
1975                 pr_err("%s can't get bitmap from slot %d\n", __func__, slot);
1976                 return -1;
1977         }
1978
1979         counts = &bitmap->counts;
1980         for (j = 0; j < counts->chunks; j++) {
1981                 block = (sector_t)j << counts->chunkshift;
1982                 if (bitmap_file_test_bit(bitmap, block)) {
1983                         if (!lo)
1984                                 lo = block;
1985                         hi = block;
1986                         bitmap_file_clear_bit(bitmap, block);
1987                         bitmap_set_memory_bits(mddev->bitmap, block, 1);
1988                         bitmap_file_set_bit(mddev->bitmap, block);
1989                 }
1990         }
1991
1992         if (clear_bits) {
1993                 bitmap_update_sb(bitmap);
1994                 /* BITMAP_PAGE_PENDING is set, but bitmap_unplug needs
1995                  * BITMAP_PAGE_DIRTY or _NEEDWRITE to write ... */
1996                 for (i = 0; i < bitmap->storage.file_pages; i++)
1997                         if (test_page_attr(bitmap, i, BITMAP_PAGE_PENDING))
1998                                 set_page_attr(bitmap, i, BITMAP_PAGE_NEEDWRITE);
1999                 bitmap_unplug(bitmap);
2000         }
2001         bitmap_unplug(mddev->bitmap);
2002         *low = lo;
2003         *high = hi;
2004
2005         return rv;
2006 }
2007 EXPORT_SYMBOL_GPL(bitmap_copy_from_slot);
2008
2009
2010 void bitmap_status(struct seq_file *seq, struct bitmap *bitmap)
2011 {
2012         unsigned long chunk_kb;
2013         struct bitmap_counts *counts;
2014
2015         if (!bitmap)
2016                 return;
2017
2018         counts = &bitmap->counts;
2019
2020         chunk_kb = bitmap->mddev->bitmap_info.chunksize >> 10;
2021         seq_printf(seq, "bitmap: %lu/%lu pages [%luKB], "
2022                    "%lu%s chunk",
2023                    counts->pages - counts->missing_pages,
2024                    counts->pages,
2025                    (counts->pages - counts->missing_pages)
2026                    << (PAGE_SHIFT - 10),
2027                    chunk_kb ? chunk_kb : bitmap->mddev->bitmap_info.chunksize,
2028                    chunk_kb ? "KB" : "B");
2029         if (bitmap->storage.file) {
2030                 seq_printf(seq, ", file: ");
2031                 seq_file_path(seq, bitmap->storage.file, " \t\n");
2032         }
2033
2034         seq_printf(seq, "\n");
2035 }
2036
2037 int bitmap_resize(struct bitmap *bitmap, sector_t blocks,
2038                   int chunksize, int init)
2039 {
2040         /* If chunk_size is 0, choose an appropriate chunk size.
2041          * Then possibly allocate new storage space.
2042          * Then quiesce, copy bits, replace bitmap, and re-start
2043          *
2044          * This function is called both to set up the initial bitmap
2045          * and to resize the bitmap while the array is active.
2046          * If this happens as a result of the array being resized,
2047          * chunksize will be zero, and we need to choose a suitable
2048          * chunksize, otherwise we use what we are given.
2049          */
2050         struct bitmap_storage store;
2051         struct bitmap_counts old_counts;
2052         unsigned long chunks;
2053         sector_t block;
2054         sector_t old_blocks, new_blocks;
2055         int chunkshift;
2056         int ret = 0;
2057         long pages;
2058         struct bitmap_page *new_bp;
2059
2060         if (chunksize == 0) {
2061                 /* If there is enough space, leave the chunk size unchanged,
2062                  * else increase by factor of two until there is enough space.
2063                  */
2064                 long bytes;
2065                 long space = bitmap->mddev->bitmap_info.space;
2066
2067                 if (space == 0) {
2068                         /* We don't know how much space there is, so limit
2069                          * to current size - in sectors.
2070                          */
2071                         bytes = DIV_ROUND_UP(bitmap->counts.chunks, 8);
2072                         if (!bitmap->mddev->bitmap_info.external)
2073                                 bytes += sizeof(bitmap_super_t);
2074                         space = DIV_ROUND_UP(bytes, 512);
2075                         bitmap->mddev->bitmap_info.space = space;
2076                 }
2077                 chunkshift = bitmap->counts.chunkshift;
2078                 chunkshift--;
2079                 do {
2080                         /* 'chunkshift' is shift from block size to chunk size */
2081                         chunkshift++;
2082                         chunks = DIV_ROUND_UP_SECTOR_T(blocks, 1 << chunkshift);
2083                         bytes = DIV_ROUND_UP(chunks, 8);
2084                         if (!bitmap->mddev->bitmap_info.external)
2085                                 bytes += sizeof(bitmap_super_t);
2086                 } while (bytes > (space << 9));
2087         } else
2088                 chunkshift = ffz(~chunksize) - BITMAP_BLOCK_SHIFT;
2089
2090         chunks = DIV_ROUND_UP_SECTOR_T(blocks, 1 << chunkshift);
2091         memset(&store, 0, sizeof(store));
2092         if (bitmap->mddev->bitmap_info.offset || bitmap->mddev->bitmap_info.file)
2093                 ret = bitmap_storage_alloc(&store, chunks,
2094                                            !bitmap->mddev->bitmap_info.external,
2095                                            mddev_is_clustered(bitmap->mddev)
2096                                            ? bitmap->cluster_slot : 0);
2097         if (ret) {
2098                 bitmap_file_unmap(&store);
2099                 goto err;
2100         }
2101
2102         pages = DIV_ROUND_UP(chunks, PAGE_COUNTER_RATIO);
2103
2104         new_bp = kzalloc(pages * sizeof(*new_bp), GFP_KERNEL);
2105         ret = -ENOMEM;
2106         if (!new_bp) {
2107                 bitmap_file_unmap(&store);
2108                 goto err;
2109         }
2110
2111         if (!init)
2112                 bitmap->mddev->pers->quiesce(bitmap->mddev, 1);
2113
2114         store.file = bitmap->storage.file;
2115         bitmap->storage.file = NULL;
2116
2117         if (store.sb_page && bitmap->storage.sb_page)
2118                 memcpy(page_address(store.sb_page),
2119                        page_address(bitmap->storage.sb_page),
2120                        sizeof(bitmap_super_t));
2121         bitmap_file_unmap(&bitmap->storage);
2122         bitmap->storage = store;
2123
2124         old_counts = bitmap->counts;
2125         bitmap->counts.bp = new_bp;
2126         bitmap->counts.pages = pages;
2127         bitmap->counts.missing_pages = pages;
2128         bitmap->counts.chunkshift = chunkshift;
2129         bitmap->counts.chunks = chunks;
2130         bitmap->mddev->bitmap_info.chunksize = 1 << (chunkshift +
2131                                                      BITMAP_BLOCK_SHIFT);
2132
2133         blocks = min(old_counts.chunks << old_counts.chunkshift,
2134                      chunks << chunkshift);
2135
2136         spin_lock_irq(&bitmap->counts.lock);
2137         /* For cluster raid, need to pre-allocate bitmap */
2138         if (mddev_is_clustered(bitmap->mddev)) {
2139                 unsigned long page;
2140                 for (page = 0; page < pages; page++) {
2141                         ret = bitmap_checkpage(&bitmap->counts, page, 1, 1);
2142                         if (ret) {
2143                                 unsigned long k;
2144
2145                                 /* deallocate the page memory */
2146                                 for (k = 0; k < page; k++) {
2147                                         kfree(new_bp[k].map);
2148                                 }
2149
2150                                 /* restore some fields from old_counts */
2151                                 bitmap->counts.bp = old_counts.bp;
2152                                 bitmap->counts.pages = old_counts.pages;
2153                                 bitmap->counts.missing_pages = old_counts.pages;
2154                                 bitmap->counts.chunkshift = old_counts.chunkshift;
2155                                 bitmap->counts.chunks = old_counts.chunks;
2156                                 bitmap->mddev->bitmap_info.chunksize = 1 << (old_counts.chunkshift +
2157                                                                              BITMAP_BLOCK_SHIFT);
2158                                 blocks = old_counts.chunks << old_counts.chunkshift;
2159                                 pr_warn("Could not pre-allocate in-memory bitmap for cluster raid\n");
2160                                 break;
2161                         } else
2162                                 bitmap->counts.bp[page].count += 1;
2163                 }
2164         }
2165
2166         for (block = 0; block < blocks; ) {
2167                 bitmap_counter_t *bmc_old, *bmc_new;
2168                 int set;
2169
2170                 bmc_old = bitmap_get_counter(&old_counts, block,
2171                                              &old_blocks, 0);
2172                 set = bmc_old && NEEDED(*bmc_old);
2173
2174                 if (set) {
2175                         bmc_new = bitmap_get_counter(&bitmap->counts, block,
2176                                                      &new_blocks, 1);
2177                         if (*bmc_new == 0) {
2178                                 /* need to set on-disk bits too. */
2179                                 sector_t end = block + new_blocks;
2180                                 sector_t start = block >> chunkshift;
2181                                 start <<= chunkshift;
2182                                 while (start < end) {
2183                                         bitmap_file_set_bit(bitmap, block);
2184                                         start += 1 << chunkshift;
2185                                 }
2186                                 *bmc_new = 2;
2187                                 bitmap_count_page(&bitmap->counts,
2188                                                   block, 1);
2189                                 bitmap_set_pending(&bitmap->counts,
2190                                                    block);
2191                         }
2192                         *bmc_new |= NEEDED_MASK;
2193                         if (new_blocks < old_blocks)
2194                                 old_blocks = new_blocks;
2195                 }
2196                 block += old_blocks;
2197         }
2198
2199         if (!init) {
2200                 int i;
2201                 while (block < (chunks << chunkshift)) {
2202                         bitmap_counter_t *bmc;
2203                         bmc = bitmap_get_counter(&bitmap->counts, block,
2204                                                  &new_blocks, 1);
2205                         if (bmc) {
2206                                 /* new space.  It needs to be resynced, so
2207                                  * we set NEEDED_MASK.
2208                                  */
2209                                 if (*bmc == 0) {
2210                                         *bmc = NEEDED_MASK | 2;
2211                                         bitmap_count_page(&bitmap->counts,
2212                                                           block, 1);
2213                                         bitmap_set_pending(&bitmap->counts,
2214                                                            block);
2215                                 }
2216                         }
2217                         block += new_blocks;
2218                 }
2219                 for (i = 0; i < bitmap->storage.file_pages; i++)
2220                         set_page_attr(bitmap, i, BITMAP_PAGE_DIRTY);
2221         }
2222         spin_unlock_irq(&bitmap->counts.lock);
2223
2224         if (!init) {
2225                 bitmap_unplug(bitmap);
2226                 bitmap->mddev->pers->quiesce(bitmap->mddev, 0);
2227         }
2228         ret = 0;
2229 err:
2230         return ret;
2231 }
2232 EXPORT_SYMBOL_GPL(bitmap_resize);
2233
2234 static ssize_t
2235 location_show(struct mddev *mddev, char *page)
2236 {
2237         ssize_t len;
2238         if (mddev->bitmap_info.file)
2239                 len = sprintf(page, "file");
2240         else if (mddev->bitmap_info.offset)
2241                 len = sprintf(page, "%+lld", (long long)mddev->bitmap_info.offset);
2242         else
2243                 len = sprintf(page, "none");
2244         len += sprintf(page+len, "\n");
2245         return len;
2246 }
2247
2248 static ssize_t
2249 location_store(struct mddev *mddev, const char *buf, size_t len)
2250 {
2251         int rv;
2252
2253         rv = mddev_lock(mddev);
2254         if (rv)
2255                 return rv;
2256         if (mddev->pers) {
2257                 if (!mddev->pers->quiesce) {
2258                         rv = -EBUSY;
2259                         goto out;
2260                 }
2261                 if (mddev->recovery || mddev->sync_thread) {
2262                         rv = -EBUSY;
2263                         goto out;
2264                 }
2265         }
2266
2267         if (mddev->bitmap || mddev->bitmap_info.file ||
2268             mddev->bitmap_info.offset) {
2269                 /* bitmap already configured.  Only option is to clear it */
2270                 if (strncmp(buf, "none", 4) != 0) {
2271                         rv = -EBUSY;
2272                         goto out;
2273                 }
2274                 if (mddev->pers) {
2275                         mddev->pers->quiesce(mddev, 1);
2276                         bitmap_destroy(mddev);
2277                         mddev->pers->quiesce(mddev, 0);
2278                 }
2279                 mddev->bitmap_info.offset = 0;
2280                 if (mddev->bitmap_info.file) {
2281                         struct file *f = mddev->bitmap_info.file;
2282                         mddev->bitmap_info.file = NULL;
2283                         fput(f);
2284                 }
2285         } else {
2286                 /* No bitmap, OK to set a location */
2287                 long long offset;
2288                 if (strncmp(buf, "none", 4) == 0)
2289                         /* nothing to be done */;
2290                 else if (strncmp(buf, "file:", 5) == 0) {
2291                         /* Not supported yet */
2292                         rv = -EINVAL;
2293                         goto out;
2294                 } else {
2295                         if (buf[0] == '+')
2296                                 rv = kstrtoll(buf+1, 10, &offset);
2297                         else
2298                                 rv = kstrtoll(buf, 10, &offset);
2299                         if (rv)
2300                                 goto out;
2301                         if (offset == 0) {
2302                                 rv = -EINVAL;
2303                                 goto out;
2304                         }
2305                         if (mddev->bitmap_info.external == 0 &&
2306                             mddev->major_version == 0 &&
2307                             offset != mddev->bitmap_info.default_offset) {
2308                                 rv = -EINVAL;
2309                                 goto out;
2310                         }
2311                         mddev->bitmap_info.offset = offset;
2312                         if (mddev->pers) {
2313                                 struct bitmap *bitmap;
2314                                 mddev->pers->quiesce(mddev, 1);
2315                                 bitmap = bitmap_create(mddev, -1);
2316                                 if (IS_ERR(bitmap))
2317                                         rv = PTR_ERR(bitmap);
2318                                 else {
2319                                         mddev->bitmap = bitmap;
2320                                         rv = bitmap_load(mddev);
2321                                         if (rv)
2322                                                 mddev->bitmap_info.offset = 0;
2323                                 }
2324                                 mddev->pers->quiesce(mddev, 0);
2325                                 if (rv) {
2326                                         bitmap_destroy(mddev);
2327                                         goto out;
2328                                 }
2329                         }
2330                 }
2331         }
2332         if (!mddev->external) {
2333                 /* Ensure new bitmap info is stored in
2334                  * metadata promptly.
2335                  */
2336                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
2337                 md_wakeup_thread(mddev->thread);
2338         }
2339         rv = 0;
2340 out:
2341         mddev_unlock(mddev);
2342         if (rv)
2343                 return rv;
2344         return len;
2345 }
2346
2347 static struct md_sysfs_entry bitmap_location =
2348 __ATTR(location, S_IRUGO|S_IWUSR, location_show, location_store);
2349
2350 /* 'bitmap/space' is the space available at 'location' for the
2351  * bitmap.  This allows the kernel to know when it is safe to
2352  * resize the bitmap to match a resized array.
2353  */
2354 static ssize_t
2355 space_show(struct mddev *mddev, char *page)
2356 {
2357         return sprintf(page, "%lu\n", mddev->bitmap_info.space);
2358 }
2359
2360 static ssize_t
2361 space_store(struct mddev *mddev, const char *buf, size_t len)
2362 {
2363         unsigned long sectors;
2364         int rv;
2365
2366         rv = kstrtoul(buf, 10, &sectors);
2367         if (rv)
2368                 return rv;
2369
2370         if (sectors == 0)
2371                 return -EINVAL;
2372
2373         if (mddev->bitmap &&
2374             sectors < (mddev->bitmap->storage.bytes + 511) >> 9)
2375                 return -EFBIG; /* Bitmap is too big for this small space */
2376
2377         /* could make sure it isn't too big, but that isn't really
2378          * needed - user-space should be careful.
2379          */
2380         mddev->bitmap_info.space = sectors;
2381         return len;
2382 }
2383
2384 static struct md_sysfs_entry bitmap_space =
2385 __ATTR(space, S_IRUGO|S_IWUSR, space_show, space_store);
2386
2387 static ssize_t
2388 timeout_show(struct mddev *mddev, char *page)
2389 {
2390         ssize_t len;
2391         unsigned long secs = mddev->bitmap_info.daemon_sleep / HZ;
2392         unsigned long jifs = mddev->bitmap_info.daemon_sleep % HZ;
2393
2394         len = sprintf(page, "%lu", secs);
2395         if (jifs)
2396                 len += sprintf(page+len, ".%03u", jiffies_to_msecs(jifs));
2397         len += sprintf(page+len, "\n");
2398         return len;
2399 }
2400
2401 static ssize_t
2402 timeout_store(struct mddev *mddev, const char *buf, size_t len)
2403 {
2404         /* timeout can be set at any time */
2405         unsigned long timeout;
2406         int rv = strict_strtoul_scaled(buf, &timeout, 4);
2407         if (rv)
2408                 return rv;
2409
2410         /* just to make sure we don't overflow... */
2411         if (timeout >= LONG_MAX / HZ)
2412                 return -EINVAL;
2413
2414         timeout = timeout * HZ / 10000;
2415
2416         if (timeout >= MAX_SCHEDULE_TIMEOUT)
2417                 timeout = MAX_SCHEDULE_TIMEOUT-1;
2418         if (timeout < 1)
2419                 timeout = 1;
2420         mddev->bitmap_info.daemon_sleep = timeout;
2421         if (mddev->thread) {
2422                 /* if thread->timeout is MAX_SCHEDULE_TIMEOUT, then
2423                  * the bitmap is all clean and we don't need to
2424                  * adjust the timeout right now
2425                  */
2426                 if (mddev->thread->timeout < MAX_SCHEDULE_TIMEOUT) {
2427                         mddev->thread->timeout = timeout;
2428                         md_wakeup_thread(mddev->thread);
2429                 }
2430         }
2431         return len;
2432 }
2433
2434 static struct md_sysfs_entry bitmap_timeout =
2435 __ATTR(time_base, S_IRUGO|S_IWUSR, timeout_show, timeout_store);
2436
2437 static ssize_t
2438 backlog_show(struct mddev *mddev, char *page)
2439 {
2440         return sprintf(page, "%lu\n", mddev->bitmap_info.max_write_behind);
2441 }
2442
2443 static ssize_t
2444 backlog_store(struct mddev *mddev, const char *buf, size_t len)
2445 {
2446         unsigned long backlog;
2447         int rv = kstrtoul(buf, 10, &backlog);
2448         if (rv)
2449                 return rv;
2450         if (backlog > COUNTER_MAX)
2451                 return -EINVAL;
2452         mddev->bitmap_info.max_write_behind = backlog;
2453         return len;
2454 }
2455
2456 static struct md_sysfs_entry bitmap_backlog =
2457 __ATTR(backlog, S_IRUGO|S_IWUSR, backlog_show, backlog_store);
2458
2459 static ssize_t
2460 chunksize_show(struct mddev *mddev, char *page)
2461 {
2462         return sprintf(page, "%lu\n", mddev->bitmap_info.chunksize);
2463 }
2464
2465 static ssize_t
2466 chunksize_store(struct mddev *mddev, const char *buf, size_t len)
2467 {
2468         /* Can only be changed when no bitmap is active */
2469         int rv;
2470         unsigned long csize;
2471         if (mddev->bitmap)
2472                 return -EBUSY;
2473         rv = kstrtoul(buf, 10, &csize);
2474         if (rv)
2475                 return rv;
2476         if (csize < 512 ||
2477             !is_power_of_2(csize))
2478                 return -EINVAL;
2479         mddev->bitmap_info.chunksize = csize;
2480         return len;
2481 }
2482
2483 static struct md_sysfs_entry bitmap_chunksize =
2484 __ATTR(chunksize, S_IRUGO|S_IWUSR, chunksize_show, chunksize_store);
2485
2486 static ssize_t metadata_show(struct mddev *mddev, char *page)
2487 {
2488         if (mddev_is_clustered(mddev))
2489                 return sprintf(page, "clustered\n");
2490         return sprintf(page, "%s\n", (mddev->bitmap_info.external
2491                                       ? "external" : "internal"));
2492 }
2493
2494 static ssize_t metadata_store(struct mddev *mddev, const char *buf, size_t len)
2495 {
2496         if (mddev->bitmap ||
2497             mddev->bitmap_info.file ||
2498             mddev->bitmap_info.offset)
2499                 return -EBUSY;
2500         if (strncmp(buf, "external", 8) == 0)
2501                 mddev->bitmap_info.external = 1;
2502         else if ((strncmp(buf, "internal", 8) == 0) ||
2503                         (strncmp(buf, "clustered", 9) == 0))
2504                 mddev->bitmap_info.external = 0;
2505         else
2506                 return -EINVAL;
2507         return len;
2508 }
2509
2510 static struct md_sysfs_entry bitmap_metadata =
2511 __ATTR(metadata, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
2512
2513 static ssize_t can_clear_show(struct mddev *mddev, char *page)
2514 {
2515         int len;
2516         spin_lock(&mddev->lock);
2517         if (mddev->bitmap)
2518                 len = sprintf(page, "%s\n", (mddev->bitmap->need_sync ?
2519                                              "false" : "true"));
2520         else
2521                 len = sprintf(page, "\n");
2522         spin_unlock(&mddev->lock);
2523         return len;
2524 }
2525
2526 static ssize_t can_clear_store(struct mddev *mddev, const char *buf, size_t len)
2527 {
2528         if (mddev->bitmap == NULL)
2529                 return -ENOENT;
2530         if (strncmp(buf, "false", 5) == 0)
2531                 mddev->bitmap->need_sync = 1;
2532         else if (strncmp(buf, "true", 4) == 0) {
2533                 if (mddev->degraded)
2534                         return -EBUSY;
2535                 mddev->bitmap->need_sync = 0;
2536         } else
2537                 return -EINVAL;
2538         return len;
2539 }
2540
2541 static struct md_sysfs_entry bitmap_can_clear =
2542 __ATTR(can_clear, S_IRUGO|S_IWUSR, can_clear_show, can_clear_store);
2543
2544 static ssize_t
2545 behind_writes_used_show(struct mddev *mddev, char *page)
2546 {
2547         ssize_t ret;
2548         spin_lock(&mddev->lock);
2549         if (mddev->bitmap == NULL)
2550                 ret = sprintf(page, "0\n");
2551         else
2552                 ret = sprintf(page, "%lu\n",
2553                               mddev->bitmap->behind_writes_used);
2554         spin_unlock(&mddev->lock);
2555         return ret;
2556 }
2557
2558 static ssize_t
2559 behind_writes_used_reset(struct mddev *mddev, const char *buf, size_t len)
2560 {
2561         if (mddev->bitmap)
2562                 mddev->bitmap->behind_writes_used = 0;
2563         return len;
2564 }
2565
2566 static struct md_sysfs_entry max_backlog_used =
2567 __ATTR(max_backlog_used, S_IRUGO | S_IWUSR,
2568        behind_writes_used_show, behind_writes_used_reset);
2569
2570 static struct attribute *md_bitmap_attrs[] = {
2571         &bitmap_location.attr,
2572         &bitmap_space.attr,
2573         &bitmap_timeout.attr,
2574         &bitmap_backlog.attr,
2575         &bitmap_chunksize.attr,
2576         &bitmap_metadata.attr,
2577         &bitmap_can_clear.attr,
2578         &max_backlog_used.attr,
2579         NULL
2580 };
2581 struct attribute_group md_bitmap_group = {
2582         .name = "bitmap",
2583         .attrs = md_bitmap_attrs,
2584 };
2585