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