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 "md.h"
  30 #include "bitmap.h"
  31
  32 #include <linux/dm-dirty-log.h>
  33 /* debug macros */
  34
  35 #define DEBUG 0
  36
  37 #if DEBUG
  38 /* these are for debugging purposes only! */
  39
  40 /* define one and only one of these */
  41 #define INJECT_FAULTS_1 0 /* cause bitmap_alloc_page to fail always */
  42 #define INJECT_FAULTS_2 0 /* cause bitmap file to be kicked when first bit set*/
  43 #define INJECT_FAULTS_3 0 /* treat bitmap file as kicked at init time */
  44 #define INJECT_FAULTS_4 0 /* undef */
  45 #define INJECT_FAULTS_5 0 /* undef */
  46 #define INJECT_FAULTS_6 0
  47
  48 /* if these are defined, the driver will fail! debug only */
  49 #define INJECT_FATAL_FAULT_1 0 /* fail kmalloc, causing bitmap_create to fail */
  50 #define INJECT_FATAL_FAULT_2 0 /* undef */
  51 #define INJECT_FATAL_FAULT_3 0 /* undef */
  52 #endif
  53
  54 #ifndef PRINTK
  55 #  if DEBUG > 0
  56 #    define PRINTK(x...) printk(KERN_DEBUG x)
  57 #  else
  58 #    define PRINTK(x...)
  59 #  endif
  60 #endif
  61
  62 static inline char *bmname(struct bitmap *bitmap)
  63 {
  64         return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
  65 }
  66
  67 /*
  68  * just a placeholder - calls kmalloc for bitmap pages
  69  */
  70 static unsigned char *bitmap_alloc_page(struct bitmap *bitmap)
  71 {
  72         unsigned char *page;
  73
  74 #ifdef INJECT_FAULTS_1
  75         page = NULL;
  76 #else
  77         page = kzalloc(PAGE_SIZE, GFP_NOIO);
  78 #endif
  79         if (!page)
  80                 printk("%s: bitmap_alloc_page FAILED\n", bmname(bitmap));
  81         else
  82                 PRINTK("%s: bitmap_alloc_page: allocated page at %p\n",
  83                         bmname(bitmap), page);
  84         return page;
  85 }
  86
  87 /*
  88  * for now just a placeholder -- just calls kfree for bitmap pages
  89  */
  90 static void bitmap_free_page(struct bitmap *bitmap, unsigned char *page)
  91 {
  92         PRINTK("%s: bitmap_free_page: free page %p\n", bmname(bitmap), page);
  93         kfree(page);
  94 }
  95
  96 /*
  97  * check a page and, if necessary, allocate it (or hijack it if the alloc fails)
  98  *
  99  * 1) check to see if this page is allocated, if it's not then try to alloc
 100  * 2) if the alloc fails, set the page's hijacked flag so we'll use the
 101  *    page pointer directly as a counter
 102  *
 103  * if we find our page, we increment the page's refcount so that it stays
 104  * allocated while we're using it
 105  */
 106 static int bitmap_checkpage(struct bitmap *bitmap,
 107                             unsigned long page, int create)
 108 __releases(bitmap->lock)
 109 __acquires(bitmap->lock)
 110 {
 111         unsigned char *mappage;
 112
 113         if (page >= bitmap->pages) {
 114                 /* This can happen if bitmap_start_sync goes beyond
 115                  * End-of-device while looking for a whole page.
 116                  * It is harmless.
 117                  */
 118                 return -EINVAL;
 119         }
 120
 121         if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
 122                 return 0;
 123
 124         if (bitmap->bp[page].map) /* page is already allocated, just return */
 125                 return 0;
 126
 127         if (!create)
 128                 return -ENOENT;
 129
 130         /* this page has not been allocated yet */
 131
 132         spin_unlock_irq(&bitmap->lock);
 133         mappage = bitmap_alloc_page(bitmap);
 134         spin_lock_irq(&bitmap->lock);
 135
 136         if (mappage == NULL) {
 137                 PRINTK("%s: bitmap map page allocation failed, hijacking\n",
 138                         bmname(bitmap));
 139                 /* failed - set the hijacked flag so that we can use the
 140                  * pointer as a counter */
 141                 if (!bitmap->bp[page].map)
 142                         bitmap->bp[page].hijacked = 1;
 143         } else if (bitmap->bp[page].map ||
 144                    bitmap->bp[page].hijacked) {
 145                 /* somebody beat us to getting the page */
 146                 bitmap_free_page(bitmap, mappage);
 147                 return 0;
 148         } else {
 149
 150                 /* no page was in place and we have one, so install it */
 151
 152                 bitmap->bp[page].map = mappage;
 153                 bitmap->missing_pages--;
 154         }
 155         return 0;
 156 }
 157
 158 /* if page is completely empty, put it back on the free list, or dealloc it */
 159 /* if page was hijacked, unmark the flag so it might get alloced next time */
 160 /* Note: lock should be held when calling this */
 161 static void bitmap_checkfree(struct bitmap *bitmap, unsigned long page)
 162 {
 163         char *ptr;
 164
 165         if (bitmap->bp[page].count) /* page is still busy */
 166                 return;
 167
 168         /* page is no longer in use, it can be released */
 169
 170         if (bitmap->bp[page].hijacked) { /* page was hijacked, undo this now */
 171                 bitmap->bp[page].hijacked = 0;
 172                 bitmap->bp[page].map = NULL;
 173         } else {
 174                 /* normal case, free the page */
 175                 ptr = bitmap->bp[page].map;
 176                 bitmap->bp[page].map = NULL;
 177                 bitmap->missing_pages++;
 178                 bitmap_free_page(bitmap, ptr);
 179         }
 180 }
 181
 182 /*
 183  * bitmap file handling - read and write the bitmap file and its superblock
 184  */
 185
 186 /*
 187  * basic page I/O operations
 188  */
 189
 190 /* IO operations when bitmap is stored near all superblocks */
 191 static struct page *read_sb_page(mddev_t *mddev, loff_t offset,
 192                                  struct page *page,
 193                                  unsigned long index, int size)
 194 {
 195         /* choose a good rdev and read the page from there */
 196
 197         mdk_rdev_t *rdev;
 198         sector_t target;
 199         int did_alloc = 0;
 200
 201         if (!page) {
 202                 page = alloc_page(GFP_KERNEL);
 203                 if (!page)
 204                         return ERR_PTR(-ENOMEM);
 205                 did_alloc = 1;
 206         }
 207
 208         list_for_each_entry(rdev, &mddev->disks, same_set) {
 209                 if (! test_bit(In_sync, &rdev->flags)
 210                     || test_bit(Faulty, &rdev->flags))
 211                         continue;
 212
 213                 target = offset + index * (PAGE_SIZE/512);
 214
 215                 if (sync_page_io(rdev, target,
 216                                  roundup(size, bdev_logical_block_size(rdev->bdev)),
 217                                  page, READ, true)) {
 218                         page->index = index;
 219                         attach_page_buffers(page, NULL); /* so that free_buffer will
 220                                                           * quietly no-op */
 221                         return page;
 222                 }
 223         }
 224         if (did_alloc)
 225                 put_page(page);
 226         return ERR_PTR(-EIO);
 227
 228 }
 229
 230 static mdk_rdev_t *next_active_rdev(mdk_rdev_t *rdev, mddev_t *mddev)
 231 {
 232         /* Iterate the disks of an mddev, using rcu to protect access to the
 233          * linked list, and raising the refcount of devices we return to ensure
 234          * they don't disappear while in use.
 235          * As devices are only added or removed when raid_disk is < 0 and
 236          * nr_pending is 0 and In_sync is clear, the entries we return will
 237          * still be in the same position on the list when we re-enter
 238          * list_for_each_continue_rcu.
 239          */
 240         struct list_head *pos;
 241         rcu_read_lock();
 242         if (rdev == NULL)
 243                 /* start at the beginning */
 244                 pos = &mddev->disks;
 245         else {
 246                 /* release the previous rdev and start from there. */
 247                 rdev_dec_pending(rdev, mddev);
 248                 pos = &rdev->same_set;
 249         }
 250         list_for_each_continue_rcu(pos, &mddev->disks) {
 251                 rdev = list_entry(pos, mdk_rdev_t, same_set);
 252                 if (rdev->raid_disk >= 0 &&
 253                     !test_bit(Faulty, &rdev->flags)) {
 254                         /* this is a usable devices */
 255                         atomic_inc(&rdev->nr_pending);
 256                         rcu_read_unlock();
 257                         return rdev;
 258                 }
 259         }
 260         rcu_read_unlock();
 261         return NULL;
 262 }
 263
 264 static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
 265 {
 266         mdk_rdev_t *rdev = NULL;
 267         struct block_device *bdev;
 268         mddev_t *mddev = bitmap->mddev;
 269
 270         while ((rdev = next_active_rdev(rdev, mddev)) != NULL) {
 271                 int size = PAGE_SIZE;
 272                 loff_t offset = mddev->bitmap_info.offset;
 273
 274                 bdev = (rdev->meta_bdev) ? rdev->meta_bdev : rdev->bdev;
 275
 276                 if (page->index == bitmap->file_pages-1)
 277                         size = roundup(bitmap->last_page_size,
 278                                        bdev_logical_block_size(bdev));
 279                 /* Just make sure we aren't corrupting data or
 280                  * metadata
 281                  */
 282                 if (mddev->external) {
 283                         /* Bitmap could be anywhere. */
 284                         if (rdev->sb_start + offset + (page->index
 285                                                        * (PAGE_SIZE/512))
 286                             > rdev->data_offset
 287                             &&
 288                             rdev->sb_start + offset
 289                             < (rdev->data_offset + mddev->dev_sectors
 290                              + (PAGE_SIZE/512)))
 291                                 goto bad_alignment;
 292                 } else if (offset < 0) {
 293                         /* DATA  BITMAP METADATA  */
 294                         if (offset
 295                             + (long)(page->index * (PAGE_SIZE/512))
 296                             + size/512 > 0)
 297                                 /* bitmap runs in to metadata */
 298                                 goto bad_alignment;
 299                         if (rdev->data_offset + mddev->dev_sectors
 300                             > rdev->sb_start + offset)
 301                                 /* data runs in to bitmap */
 302                                 goto bad_alignment;
 303                 } else if (rdev->sb_start < rdev->data_offset) {
 304                         /* METADATA BITMAP DATA */
 305                         if (rdev->sb_start
 306                             + offset
 307                             + page->index*(PAGE_SIZE/512) + size/512
 308                             > rdev->data_offset)
 309                                 /* bitmap runs in to data */
 310                                 goto bad_alignment;
 311                 } else {
 312                         /* DATA METADATA BITMAP - no problems */
 313                 }
 314                 md_super_write(mddev, rdev,
 315                                rdev->sb_start + offset
 316                                + page->index * (PAGE_SIZE/512),
 317                                size,
 318                                page);
 319         }
 320
 321         if (wait)
 322                 md_super_wait(mddev);
 323         return 0;
 324
 325  bad_alignment:
 326         return -EINVAL;
 327 }
 328
 329 static void bitmap_file_kick(struct bitmap *bitmap);
 330 /*
 331  * write out a page to a file
 332  */
 333 static void write_page(struct bitmap *bitmap, struct page *page, int wait)
 334 {
 335         struct buffer_head *bh;
 336
 337         if (bitmap->file == NULL) {
 338                 switch (write_sb_page(bitmap, page, wait)) {
 339                 case -EINVAL:
 340                         bitmap->flags |= BITMAP_WRITE_ERROR;
 341                 }
 342         } else {
 343
 344                 bh = page_buffers(page);
 345
 346                 while (bh && bh->b_blocknr) {
 347                         atomic_inc(&bitmap->pending_writes);
 348                         set_buffer_locked(bh);
 349                         set_buffer_mapped(bh);
 350                         submit_bh(WRITE | REQ_SYNC, bh);
 351                         bh = bh->b_this_page;
 352                 }
 353
 354                 if (wait)
 355                         wait_event(bitmap->write_wait,
 356                                    atomic_read(&bitmap->pending_writes)==0);
 357         }
 358         if (bitmap->flags & BITMAP_WRITE_ERROR)
 359                 bitmap_file_kick(bitmap);
 360 }
 361
 362 static void end_bitmap_write(struct buffer_head *bh, int uptodate)
 363 {
 364         struct bitmap *bitmap = bh->b_private;
 365         unsigned long flags;
 366
 367         if (!uptodate) {
 368                 spin_lock_irqsave(&bitmap->lock, flags);
 369                 bitmap->flags |= BITMAP_WRITE_ERROR;
 370                 spin_unlock_irqrestore(&bitmap->lock, flags);
 371         }
 372         if (atomic_dec_and_test(&bitmap->pending_writes))
 373                 wake_up(&bitmap->write_wait);
 374 }
 375
 376 /* copied from buffer.c */
 377 static void
 378 __clear_page_buffers(struct page *page)
 379 {
 380         ClearPagePrivate(page);
 381         set_page_private(page, 0);
 382         page_cache_release(page);
 383 }
 384 static void free_buffers(struct page *page)
 385 {
 386         struct buffer_head *bh = page_buffers(page);
 387
 388         while (bh) {
 389                 struct buffer_head *next = bh->b_this_page;
 390                 free_buffer_head(bh);
 391                 bh = next;
 392         }
 393         __clear_page_buffers(page);
 394         put_page(page);
 395 }
 396
 397 /* read a page from a file.
 398  * We both read the page, and attach buffers to the page to record the
 399  * address of each block (using bmap).  These addresses will be used
 400  * to write the block later, completely bypassing the filesystem.
 401  * This usage is similar to how swap files are handled, and allows us
 402  * to write to a file with no concerns of memory allocation failing.
 403  */
 404 static struct page *read_page(struct file *file, unsigned long index,
 405                               struct bitmap *bitmap,
 406                               unsigned long count)
 407 {
 408         struct page *page = NULL;
 409         struct inode *inode = file->f_path.dentry->d_inode;
 410         struct buffer_head *bh;
 411         sector_t block;
 412
 413         PRINTK("read bitmap file (%dB @ %llu)\n", (int)PAGE_SIZE,
 414                         (unsigned long long)index << PAGE_SHIFT);
 415
 416         page = alloc_page(GFP_KERNEL);
 417         if (!page)
 418                 page = ERR_PTR(-ENOMEM);
 419         if (IS_ERR(page))
 420                 goto out;
 421
 422         bh = alloc_page_buffers(page, 1<<inode->i_blkbits, 0);
 423         if (!bh) {
 424                 put_page(page);
 425                 page = ERR_PTR(-ENOMEM);
 426                 goto out;
 427         }
 428         attach_page_buffers(page, bh);
 429         block = index << (PAGE_SHIFT - inode->i_blkbits);
 430         while (bh) {
 431                 if (count == 0)
 432                         bh->b_blocknr = 0;
 433                 else {
 434                         bh->b_blocknr = bmap(inode, block);
 435                         if (bh->b_blocknr == 0) {
 436                                 /* Cannot use this file! */
 437                                 free_buffers(page);
 438                                 page = ERR_PTR(-EINVAL);
 439                                 goto out;
 440                         }
 441                         bh->b_bdev = inode->i_sb->s_bdev;
 442                         if (count < (1<<inode->i_blkbits))
 443                                 count = 0;
 444                         else
 445                                 count -= (1<<inode->i_blkbits);
 446
 447                         bh->b_end_io = end_bitmap_write;
 448                         bh->b_private = bitmap;
 449                         atomic_inc(&bitmap->pending_writes);
 450                         set_buffer_locked(bh);
 451                         set_buffer_mapped(bh);
 452                         submit_bh(READ, bh);
 453                 }
 454                 block++;
 455                 bh = bh->b_this_page;
 456         }
 457         page->index = index;
 458
 459         wait_event(bitmap->write_wait,
 460                    atomic_read(&bitmap->pending_writes)==0);
 461         if (bitmap->flags & BITMAP_WRITE_ERROR) {
 462                 free_buffers(page);
 463                 page = ERR_PTR(-EIO);
 464         }
 465 out:
 466         if (IS_ERR(page))
 467                 printk(KERN_ALERT "md: bitmap read error: (%dB @ %llu): %ld\n",
 468                         (int)PAGE_SIZE,
 469                         (unsigned long long)index << PAGE_SHIFT,
 470                         PTR_ERR(page));
 471         return page;
 472 }
 473
 474 /*
 475  * bitmap file superblock operations
 476  */
 477
 478 /* update the event counter and sync the superblock to disk */
 479 void bitmap_update_sb(struct bitmap *bitmap)
 480 {
 481         bitmap_super_t *sb;
 482         unsigned long flags;
 483
 484         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
 485                 return;
 486         if (bitmap->mddev->bitmap_info.external)
 487                 return;
 488         spin_lock_irqsave(&bitmap->lock, flags);
 489         if (!bitmap->sb_page) { /* no superblock */
 490                 spin_unlock_irqrestore(&bitmap->lock, flags);
 491                 return;
 492         }
 493         spin_unlock_irqrestore(&bitmap->lock, flags);
 494         sb = kmap_atomic(bitmap->sb_page, KM_USER0);
 495         sb->events = cpu_to_le64(bitmap->mddev->events);
 496         if (bitmap->mddev->events < bitmap->events_cleared)
 497                 /* rocking back to read-only */
 498                 bitmap->events_cleared = bitmap->mddev->events;
 499         sb->events_cleared = cpu_to_le64(bitmap->events_cleared);
 500         sb->state = cpu_to_le32(bitmap->flags);
 501         /* Just in case these have been changed via sysfs: */
 502         sb->daemon_sleep = cpu_to_le32(bitmap->mddev->bitmap_info.daemon_sleep/HZ);
 503         sb->write_behind = cpu_to_le32(bitmap->mddev->bitmap_info.max_write_behind);
 504         kunmap_atomic(sb, KM_USER0);
 505         write_page(bitmap, bitmap->sb_page, 1);
 506 }
 507
 508 /* print out the bitmap file superblock */
 509 void bitmap_print_sb(struct bitmap *bitmap)
 510 {
 511         bitmap_super_t *sb;
 512
 513         if (!bitmap || !bitmap->sb_page)
 514                 return;
 515         sb = kmap_atomic(bitmap->sb_page, KM_USER0);
 516         printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
 517         printk(KERN_DEBUG "         magic: %08x\n", le32_to_cpu(sb->magic));
 518         printk(KERN_DEBUG "       version: %d\n", le32_to_cpu(sb->version));
 519         printk(KERN_DEBUG "          uuid: %08x.%08x.%08x.%08x\n",
 520                                         *(__u32 *)(sb->uuid+0),
 521                                         *(__u32 *)(sb->uuid+4),
 522                                         *(__u32 *)(sb->uuid+8),
 523                                         *(__u32 *)(sb->uuid+12));
 524         printk(KERN_DEBUG "        events: %llu\n",
 525                         (unsigned long long) le64_to_cpu(sb->events));
 526         printk(KERN_DEBUG "events cleared: %llu\n",
 527                         (unsigned long long) le64_to_cpu(sb->events_cleared));
 528         printk(KERN_DEBUG "         state: %08x\n", le32_to_cpu(sb->state));
 529         printk(KERN_DEBUG "     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
 530         printk(KERN_DEBUG "  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
 531         printk(KERN_DEBUG "     sync size: %llu KB\n",
 532                         (unsigned long long)le64_to_cpu(sb->sync_size)/2);
 533         printk(KERN_DEBUG "max write behind: %d\n", le32_to_cpu(sb->write_behind));
 534         kunmap_atomic(sb, KM_USER0);
 535 }
 536
 537 /* read the superblock from the bitmap file and initialize some bitmap fields */
 538 static int bitmap_read_sb(struct bitmap *bitmap)
 539 {
 540         char *reason = NULL;
 541         bitmap_super_t *sb;
 542         unsigned long chunksize, daemon_sleep, write_behind;
 543         unsigned long long events;
 544         int err = -EINVAL;
 545
 546         /* page 0 is the superblock, read it... */
 547         if (bitmap->file) {
 548                 loff_t isize = i_size_read(bitmap->file->f_mapping->host);
 549                 int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
 550
 551                 bitmap->sb_page = read_page(bitmap->file, 0, bitmap, bytes);
 552         } else {
 553                 bitmap->sb_page = read_sb_page(bitmap->mddev,
 554                                                bitmap->mddev->bitmap_info.offset,
 555                                                NULL,
 556                                                0, sizeof(bitmap_super_t));
 557         }
 558         if (IS_ERR(bitmap->sb_page)) {
 559                 err = PTR_ERR(bitmap->sb_page);
 560                 bitmap->sb_page = NULL;
 561                 return err;
 562         }
 563
 564         sb = kmap_atomic(bitmap->sb_page, KM_USER0);
 565
 566         chunksize = le32_to_cpu(sb->chunksize);
 567         daemon_sleep = le32_to_cpu(sb->daemon_sleep) * HZ;
 568         write_behind = le32_to_cpu(sb->write_behind);
 569
 570         /* verify that the bitmap-specific fields are valid */
 571         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
 572                 reason = "bad magic";
 573         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
 574                  le32_to_cpu(sb->version) > BITMAP_MAJOR_HI)
 575                 reason = "unrecognized superblock version";
 576         else if (chunksize < 512)
 577                 reason = "bitmap chunksize too small";
 578         else if ((1 << ffz(~chunksize)) != chunksize)
 579                 reason = "bitmap chunksize not a power of 2";
 580         else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT)
 581                 reason = "daemon sleep period out of range";
 582         else if (write_behind > COUNTER_MAX)
 583                 reason = "write-behind limit out of range (0 - 16383)";
 584         if (reason) {
 585                 printk(KERN_INFO "%s: invalid bitmap file superblock: %s\n",
 586                         bmname(bitmap), reason);
 587                 goto out;
 588         }
 589
 590         /* keep the array size field of the bitmap superblock up to date */
 591         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 592
 593         if (!bitmap->mddev->persistent)
 594                 goto success;
 595
 596         /*
 597          * if we have a persistent array superblock, compare the
 598          * bitmap's UUID and event counter to the mddev's
 599          */
 600         if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
 601                 printk(KERN_INFO "%s: bitmap superblock UUID mismatch\n",
 602                         bmname(bitmap));
 603                 goto out;
 604         }
 605         events = le64_to_cpu(sb->events);
 606         if (events < bitmap->mddev->events) {
 607                 printk(KERN_INFO "%s: bitmap file is out of date (%llu < %llu) "
 608                         "-- forcing full recovery\n", bmname(bitmap), events,
 609                         (unsigned long long) bitmap->mddev->events);
 610                 sb->state |= cpu_to_le32(BITMAP_STALE);
 611         }
 612 success:
 613         /* assign fields using values from superblock */
 614         bitmap->mddev->bitmap_info.chunksize = chunksize;
 615         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 616         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 617         bitmap->flags |= le32_to_cpu(sb->state);
 618         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
 619                 bitmap->flags |= BITMAP_HOSTENDIAN;
 620         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
 621         if (bitmap->flags & BITMAP_STALE)
 622                 bitmap->events_cleared = bitmap->mddev->events;
 623         err = 0;
 624 out:
 625         kunmap_atomic(sb, KM_USER0);
 626         if (err)
 627                 bitmap_print_sb(bitmap);
 628         return err;
 629 }
 630
 631 enum bitmap_mask_op {
 632         MASK_SET,
 633         MASK_UNSET
 634 };
 635
 636 /* record the state of the bitmap in the superblock.  Return the old value */
 637 static int bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
 638                              enum bitmap_mask_op op)
 639 {
 640         bitmap_super_t *sb;
 641         unsigned long flags;
 642         int old;
 643
 644         spin_lock_irqsave(&bitmap->lock, flags);
 645         if (!bitmap->sb_page) { /* can't set the state */
 646                 spin_unlock_irqrestore(&bitmap->lock, flags);
 647                 return 0;
 648         }
 649         spin_unlock_irqrestore(&bitmap->lock, flags);
 650         sb = kmap_atomic(bitmap->sb_page, KM_USER0);
 651         old = le32_to_cpu(sb->state) & bits;
 652         switch (op) {
 653         case MASK_SET:
 654                 sb->state |= cpu_to_le32(bits);
 655                 bitmap->flags |= bits;
 656                 break;
 657         case MASK_UNSET:
 658                 sb->state &= cpu_to_le32(~bits);
 659                 bitmap->flags &= ~bits;
 660                 break;
 661         default:
 662                 BUG();
 663         }
 664         kunmap_atomic(sb, KM_USER0);
 665         return old;
 666 }
 667
 668 /*
 669  * general bitmap file operations
 670  */
 671
 672 /*
 673  * on-disk bitmap:
 674  *
 675  * Use one bit per "chunk" (block set). We do the disk I/O on the bitmap
 676  * file a page at a time. There's a superblock at the start of the file.
 677  */
 678 /* calculate the index of the page that contains this bit */
 679 static inline unsigned long file_page_index(struct bitmap *bitmap, unsigned long chunk)
 680 {
 681         if (!bitmap->mddev->bitmap_info.external)
 682                 chunk += sizeof(bitmap_super_t) << 3;
 683         return chunk >> PAGE_BIT_SHIFT;
 684 }
 685
 686 /* calculate the (bit) offset of this bit within a page */
 687 static inline unsigned long file_page_offset(struct bitmap *bitmap, unsigned long chunk)
 688 {
 689         if (!bitmap->mddev->bitmap_info.external)
 690                 chunk += sizeof(bitmap_super_t) << 3;
 691         return chunk & (PAGE_BITS - 1);
 692 }
 693
 694 /*
 695  * return a pointer to the page in the filemap that contains the given bit
 696  *
 697  * this lookup is complicated by the fact that the bitmap sb might be exactly
 698  * 1 page (e.g., x86) or less than 1 page -- so the bitmap might start on page
 699  * 0 or page 1
 700  */
 701 static inline struct page *filemap_get_page(struct bitmap *bitmap,
 702                                         unsigned long chunk)
 703 {
 704         if (bitmap->filemap == NULL)
 705                 return NULL;
 706         if (file_page_index(bitmap, chunk) >= bitmap->file_pages)
 707                 return NULL;
 708         return bitmap->filemap[file_page_index(bitmap, chunk)
 709                                - file_page_index(bitmap, 0)];
 710 }
 711
 712 static void bitmap_file_unmap(struct bitmap *bitmap)
 713 {
 714         struct page **map, *sb_page;
 715         unsigned long *attr;
 716         int pages;
 717         unsigned long flags;
 718
 719         spin_lock_irqsave(&bitmap->lock, flags);
 720         map = bitmap->filemap;
 721         bitmap->filemap = NULL;
 722         attr = bitmap->filemap_attr;
 723         bitmap->filemap_attr = NULL;
 724         pages = bitmap->file_pages;
 725         bitmap->file_pages = 0;
 726         sb_page = bitmap->sb_page;
 727         bitmap->sb_page = NULL;
 728         spin_unlock_irqrestore(&bitmap->lock, flags);
 729
 730         while (pages--)
 731                 if (map[pages] != sb_page) /* 0 is sb_page, release it below */
 732                         free_buffers(map[pages]);
 733         kfree(map);
 734         kfree(attr);
 735
 736         if (sb_page)
 737                 free_buffers(sb_page);
 738 }
 739
 740 static void bitmap_file_put(struct bitmap *bitmap)
 741 {
 742         struct file *file;
 743         unsigned long flags;
 744
 745         spin_lock_irqsave(&bitmap->lock, flags);
 746         file = bitmap->file;
 747         bitmap->file = NULL;
 748         spin_unlock_irqrestore(&bitmap->lock, flags);
 749
 750         if (file)
 751                 wait_event(bitmap->write_wait,
 752                            atomic_read(&bitmap->pending_writes)==0);
 753         bitmap_file_unmap(bitmap);
 754
 755         if (file) {
 756                 struct inode *inode = file->f_path.dentry->d_inode;
 757                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
 758                 fput(file);
 759         }
 760 }
 761
 762 /*
 763  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
 764  * then it is no longer reliable, so we stop using it and we mark the file
 765  * as failed in the superblock
 766  */
 767 static void bitmap_file_kick(struct bitmap *bitmap)
 768 {
 769         char *path, *ptr = NULL;
 770
 771         if (bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET) == 0) {
 772                 bitmap_update_sb(bitmap);
 773
 774                 if (bitmap->file) {
 775                         path = kmalloc(PAGE_SIZE, GFP_KERNEL);
 776                         if (path)
 777                                 ptr = d_path(&bitmap->file->f_path, path,
 778                                              PAGE_SIZE);
 779
 780                         printk(KERN_ALERT
 781                               "%s: kicking failed bitmap file %s from array!\n",
 782                               bmname(bitmap), IS_ERR(ptr) ? "" : ptr);
 783
 784                         kfree(path);
 785                 } else
 786                         printk(KERN_ALERT
 787                                "%s: disabling internal bitmap due to errors\n",
 788                                bmname(bitmap));
 789         }
 790
 791         bitmap_file_put(bitmap);
 792
 793         return;
 794 }
 795
 796 enum bitmap_page_attr {
 797         BITMAP_PAGE_DIRTY = 0,     /* there are set bits that need to be synced */
 798         BITMAP_PAGE_CLEAN = 1,     /* there are bits that might need to be cleared */
 799         BITMAP_PAGE_NEEDWRITE = 2, /* there are cleared bits that need to be synced */
 800 };
 801
 802 static inline void set_page_attr(struct bitmap *bitmap, struct page *page,
 803                                 enum bitmap_page_attr attr)
 804 {
 805         if (page)
 806                 __set_bit((page->index<<2) + attr, bitmap->filemap_attr);
 807         else
 808                 __set_bit(attr, &bitmap->logattrs);
 809 }
 810
 811 static inline void clear_page_attr(struct bitmap *bitmap, struct page *page,
 812                                 enum bitmap_page_attr attr)
 813 {
 814         if (page)
 815                 __clear_bit((page->index<<2) + attr, bitmap->filemap_attr);
 816         else
 817                 __clear_bit(attr, &bitmap->logattrs);
 818 }
 819
 820 static inline unsigned long test_page_attr(struct bitmap *bitmap, struct page *page,
 821                                            enum bitmap_page_attr attr)
 822 {
 823         if (page)
 824                 return test_bit((page->index<<2) + attr, bitmap->filemap_attr);
 825         else
 826                 return test_bit(attr, &bitmap->logattrs);
 827 }
 828
 829 /*
 830  * bitmap_file_set_bit -- called before performing a write to the md device
 831  * to set (and eventually sync) a particular bit in the bitmap file
 832  *
 833  * we set the bit immediately, then we record the page number so that
 834  * when an unplug occurs, we can flush the dirty pages out to disk
 835  */
 836 static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 837 {
 838         unsigned long bit;
 839         struct page *page = NULL;
 840         void *kaddr;
 841         unsigned long chunk = block >> CHUNK_BLOCK_SHIFT(bitmap);
 842
 843         if (!bitmap->filemap) {
 844                 struct dm_dirty_log *log = bitmap->mddev->bitmap_info.log;
 845                 if (log)
 846                         log->type->mark_region(log, chunk);
 847         } else {
 848
 849                 page = filemap_get_page(bitmap, chunk);
 850                 if (!page)
 851                         return;
 852                 bit = file_page_offset(bitmap, chunk);
 853
 854                 /* set the bit */
 855                 kaddr = kmap_atomic(page, KM_USER0);
 856                 if (bitmap->flags & BITMAP_HOSTENDIAN)
 857                         set_bit(bit, kaddr);
 858                 else
 859                         __test_and_set_bit_le(bit, kaddr);
 860                 kunmap_atomic(kaddr, KM_USER0);
 861                 PRINTK("set file bit %lu page %lu\n", bit, page->index);
 862         }
 863         /* record page number so it gets flushed to disk when unplug occurs */
 864         set_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 865 }
 866
 867 /* this gets called when the md device is ready to unplug its underlying
 868  * (slave) device queues -- before we let any writes go down, we need to
 869  * sync the dirty pages of the bitmap file to disk */
 870 void bitmap_unplug(struct bitmap *bitmap)
 871 {
 872         unsigned long i, flags;
 873         int dirty, need_write;
 874         struct page *page;
 875         int wait = 0;
 876
 877         if (!bitmap)
 878                 return;
 879         if (!bitmap->filemap) {
 880                 /* Must be using a dirty_log */
 881                 struct dm_dirty_log *log = bitmap->mddev->bitmap_info.log;
 882                 dirty = test_and_clear_bit(BITMAP_PAGE_DIRTY, &bitmap->logattrs);
 883                 need_write = test_and_clear_bit(BITMAP_PAGE_NEEDWRITE, &bitmap->logattrs);
 884                 if (dirty || need_write)
 885                         if (log->type->flush(log))
 886                                 bitmap->flags |= BITMAP_WRITE_ERROR;
 887                 goto out;
 888         }
 889
 890         /* look at each page to see if there are any set bits that need to be
 891          * flushed out to disk */
 892         for (i = 0; i < bitmap->file_pages; i++) {
 893                 spin_lock_irqsave(&bitmap->lock, flags);
 894                 if (!bitmap->filemap) {
 895                         spin_unlock_irqrestore(&bitmap->lock, flags);
 896                         return;
 897                 }
 898                 page = bitmap->filemap[i];
 899                 dirty = test_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 900                 need_write = test_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 901                 clear_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 902                 clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 903                 if (dirty)
 904                         wait = 1;
 905                 spin_unlock_irqrestore(&bitmap->lock, flags);
 906
 907                 if (dirty || need_write)
 908                         write_page(bitmap, page, 0);
 909         }
 910         if (wait) { /* if any writes were performed, we need to wait on them */
 911                 if (bitmap->file)
 912                         wait_event(bitmap->write_wait,
 913                                    atomic_read(&bitmap->pending_writes)==0);
 914                 else
 915                         md_super_wait(bitmap->mddev);
 916         }
 917 out:
 918         if (bitmap->flags & BITMAP_WRITE_ERROR)
 919                 bitmap_file_kick(bitmap);
 920 }
 921 EXPORT_SYMBOL(bitmap_unplug);
 922
 923 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
 924 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
 925  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
 926  * memory mapping of the bitmap file
 927  * Special cases:
 928  *   if there's no bitmap file, or if the bitmap file had been
 929  *   previously kicked from the array, we mark all the bits as
 930  *   1's in order to cause a full resync.
 931  *
 932  * We ignore all bits for sectors that end earlier than 'start'.
 933  * This is used when reading an out-of-date bitmap...
 934  */
 935 static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
 936 {
 937         unsigned long i, chunks, index, oldindex, bit;
 938         struct page *page = NULL, *oldpage = NULL;
 939         unsigned long num_pages, bit_cnt = 0;
 940         struct file *file;
 941         unsigned long bytes, offset;
 942         int outofdate;
 943         int ret = -ENOSPC;
 944         void *paddr;
 945
 946         chunks = bitmap->chunks;
 947         file = bitmap->file;
 948
 949         BUG_ON(!file && !bitmap->mddev->bitmap_info.offset);
 950
 951 #ifdef INJECT_FAULTS_3
 952         outofdate = 1;
 953 #else
 954         outofdate = bitmap->flags & BITMAP_STALE;
 955 #endif
 956         if (outofdate)
 957                 printk(KERN_INFO "%s: bitmap file is out of date, doing full "
 958                         "recovery\n", bmname(bitmap));
 959
 960         bytes = DIV_ROUND_UP(bitmap->chunks, 8);
 961         if (!bitmap->mddev->bitmap_info.external)
 962                 bytes += sizeof(bitmap_super_t);
 963
 964         num_pages = DIV_ROUND_UP(bytes, PAGE_SIZE);
 965
 966         if (file && i_size_read(file->f_mapping->host) < bytes) {
 967                 printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
 968                         bmname(bitmap),
 969                         (unsigned long) i_size_read(file->f_mapping->host),
 970                         bytes);
 971                 goto err;
 972         }
 973
 974         ret = -ENOMEM;
 975
 976         bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
 977         if (!bitmap->filemap)
 978                 goto err;
 979
 980         /* We need 4 bits per page, rounded up to a multiple of sizeof(unsigned long) */
 981         bitmap->filemap_attr = kzalloc(
 982                 roundup(DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
 983                 GFP_KERNEL);
 984         if (!bitmap->filemap_attr)
 985                 goto err;
 986
 987         oldindex = ~0L;
 988
 989         for (i = 0; i < chunks; i++) {
 990                 int b;
 991                 index = file_page_index(bitmap, i);
 992                 bit = file_page_offset(bitmap, i);
 993                 if (index != oldindex) { /* this is a new page, read it in */
 994                         int count;
 995                         /* unmap the old page, we're done with it */
 996                         if (index == num_pages-1)
 997                                 count = bytes - index * PAGE_SIZE;
 998                         else
 999                                 count = PAGE_SIZE;
1000                         if (index == 0 && bitmap->sb_page) {
1001                                 /*
1002                                  * if we're here then the superblock page
1003                                  * contains some bits (PAGE_SIZE != sizeof sb)
1004                                  * we've already read it in, so just use it
1005                                  */
1006                                 page = bitmap->sb_page;
1007                                 offset = sizeof(bitmap_super_t);
1008                                 if (!file)
1009                                         page = read_sb_page(
1010                                                 bitmap->mddev,
1011                                                 bitmap->mddev->bitmap_info.offset,
1012                                                 page,
1013                                                 index, count);
1014                         } else if (file) {
1015                                 page = read_page(file, index, bitmap, count);
1016                                 offset = 0;
1017                         } else {
1018                                 page = read_sb_page(bitmap->mddev,
1019                                                     bitmap->mddev->bitmap_info.offset,
1020                                                     NULL,
1021                                                     index, count);
1022                                 offset = 0;
1023                         }
1024                         if (IS_ERR(page)) { /* read error */
1025                                 ret = PTR_ERR(page);
1026                                 goto err;
1027                         }
1028
1029                         oldindex = index;
1030                         oldpage = page;
1031
1032                         bitmap->filemap[bitmap->file_pages++] = page;
1033                         bitmap->last_page_size = count;
1034
1035                         if (outofdate) {
1036                                 /*
1037                                  * if bitmap is out of date, dirty the
1038                                  * whole page and write it out
1039                                  */
1040                                 paddr = kmap_atomic(page, KM_USER0);
1041                                 memset(paddr + offset, 0xff,
1042                                        PAGE_SIZE - offset);
1043                                 kunmap_atomic(paddr, KM_USER0);
1044                                 write_page(bitmap, page, 1);
1045
1046                                 ret = -EIO;
1047                                 if (bitmap->flags & BITMAP_WRITE_ERROR)
1048                                         goto err;
1049                         }
1050                 }
1051                 paddr = kmap_atomic(page, KM_USER0);
1052                 if (bitmap->flags & BITMAP_HOSTENDIAN)
1053                         b = test_bit(bit, paddr);
1054                 else
1055                         b = test_bit_le(bit, paddr);
1056                 kunmap_atomic(paddr, KM_USER0);
1057                 if (b) {
1058                         /* if the disk bit is set, set the memory bit */
1059                         int needed = ((sector_t)(i+1) << (CHUNK_BLOCK_SHIFT(bitmap))
1060                                       >= start);
1061                         bitmap_set_memory_bits(bitmap,
1062                                                (sector_t)i << CHUNK_BLOCK_SHIFT(bitmap),
1063                                                needed);
1064                         bit_cnt++;
1065                         set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1066                 }
1067         }
1068
1069         /* everything went OK */
1070         ret = 0;
1071         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_UNSET);
1072
1073         if (bit_cnt) { /* Kick recovery if any bits were set */
1074                 set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
1075                 md_wakeup_thread(bitmap->mddev->thread);
1076         }
1077
1078         printk(KERN_INFO "%s: bitmap initialized from disk: "
1079                 "read %lu/%lu pages, set %lu bits\n",
1080                 bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt);
1081
1082         return 0;
1083
1084  err:
1085         printk(KERN_INFO "%s: bitmap initialisation failed: %d\n",
1086                bmname(bitmap), ret);
1087         return ret;
1088 }
1089
1090 void bitmap_write_all(struct bitmap *bitmap)
1091 {
1092         /* We don't actually write all bitmap blocks here,
1093          * just flag them as needing to be written
1094          */
1095         int i;
1096
1097         for (i = 0; i < bitmap->file_pages; i++)
1098                 set_page_attr(bitmap, bitmap->filemap[i],
1099                               BITMAP_PAGE_NEEDWRITE);
1100 }
1101
1102 static void bitmap_count_page(struct bitmap *bitmap, sector_t offset, int inc)
1103 {
1104         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1105         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1106         bitmap->bp[page].count += inc;
1107         bitmap_checkfree(bitmap, page);
1108 }
1109 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1110                                             sector_t offset, sector_t *blocks,
1111                                             int create);
1112
1113 /*
1114  * bitmap daemon -- periodically wakes up to clean bits and flush pages
1115  *                      out to disk
1116  */
1117
1118 void bitmap_daemon_work(mddev_t *mddev)
1119 {
1120         struct bitmap *bitmap;
1121         unsigned long j;
1122         unsigned long flags;
1123         struct page *page = NULL, *lastpage = NULL;
1124         sector_t blocks;
1125         void *paddr;
1126         struct dm_dirty_log *log = mddev->bitmap_info.log;
1127
1128         /* Use a mutex to guard daemon_work against
1129          * bitmap_destroy.
1130          */
1131         mutex_lock(&mddev->bitmap_info.mutex);
1132         bitmap = mddev->bitmap;
1133         if (bitmap == NULL) {
1134                 mutex_unlock(&mddev->bitmap_info.mutex);
1135                 return;
1136         }
1137         if (time_before(jiffies, bitmap->daemon_lastrun
1138                         + bitmap->mddev->bitmap_info.daemon_sleep))
1139                 goto done;
1140
1141         bitmap->daemon_lastrun = jiffies;
1142         if (bitmap->allclean) {
1143                 bitmap->mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1144                 goto done;
1145         }
1146         bitmap->allclean = 1;
1147
1148         spin_lock_irqsave(&bitmap->lock, flags);
1149         for (j = 0; j < bitmap->chunks; j++) {
1150                 bitmap_counter_t *bmc;
1151                 if (!bitmap->filemap) {
1152                         if (!log)
1153                                 /* error or shutdown */
1154                                 break;
1155                 } else
1156                         page = filemap_get_page(bitmap, j);
1157
1158                 if (page != lastpage) {
1159                         /* skip this page unless it's marked as needing cleaning */
1160                         if (!test_page_attr(bitmap, page, BITMAP_PAGE_CLEAN)) {
1161                                 int need_write = test_page_attr(bitmap, page,
1162                                                                 BITMAP_PAGE_NEEDWRITE);
1163                                 if (need_write)
1164                                         clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
1165
1166                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1167                                 if (need_write) {
1168                                         write_page(bitmap, page, 0);
1169                                         bitmap->allclean = 0;
1170                                 }
1171                                 spin_lock_irqsave(&bitmap->lock, flags);
1172                                 j |= (PAGE_BITS - 1);
1173                                 continue;
1174                         }
1175
1176                         /* grab the new page, sync and release the old */
1177                         if (lastpage != NULL) {
1178                                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1179                                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1180                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1181                                         write_page(bitmap, lastpage, 0);
1182                                 } else {
1183                                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1184                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1185                                 }
1186                         } else
1187                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1188                         lastpage = page;
1189
1190                         /* We are possibly going to clear some bits, so make
1191                          * sure that events_cleared is up-to-date.
1192                          */
1193                         if (bitmap->need_sync &&
1194                             bitmap->mddev->bitmap_info.external == 0) {
1195                                 bitmap_super_t *sb;
1196                                 bitmap->need_sync = 0;
1197                                 sb = kmap_atomic(bitmap->sb_page, KM_USER0);
1198                                 sb->events_cleared =
1199                                         cpu_to_le64(bitmap->events_cleared);
1200                                 kunmap_atomic(sb, KM_USER0);
1201                                 write_page(bitmap, bitmap->sb_page, 1);
1202                         }
1203                         spin_lock_irqsave(&bitmap->lock, flags);
1204                         if (!bitmap->need_sync)
1205                                 clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1206                 }
1207                 bmc = bitmap_get_counter(bitmap,
1208                                          (sector_t)j << CHUNK_BLOCK_SHIFT(bitmap),
1209                                          &blocks, 0);
1210                 if (bmc) {
1211                         if (*bmc)
1212                                 bitmap->allclean = 0;
1213
1214                         if (*bmc == 2) {
1215                                 *bmc = 1; /* maybe clear the bit next time */
1216                                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1217                         } else if (*bmc == 1 && !bitmap->need_sync) {
1218                                 /* we can clear the bit */
1219                                 *bmc = 0;
1220                                 bitmap_count_page(bitmap,
1221                                                   (sector_t)j << CHUNK_BLOCK_SHIFT(bitmap),
1222                                                   -1);
1223
1224                                 /* clear the bit */
1225                                 if (page) {
1226                                         paddr = kmap_atomic(page, KM_USER0);
1227                                         if (bitmap->flags & BITMAP_HOSTENDIAN)
1228                                                 clear_bit(file_page_offset(bitmap, j),
1229                                                           paddr);
1230                                         else
1231                                                 __test_and_clear_bit_le(file_page_offset(bitmap, j),
1232                                                                paddr);
1233                                         kunmap_atomic(paddr, KM_USER0);
1234                                 } else
1235                                         log->type->clear_region(log, j);
1236                         }
1237                 } else
1238                         j |= PAGE_COUNTER_MASK;
1239         }
1240         spin_unlock_irqrestore(&bitmap->lock, flags);
1241
1242         /* now sync the final page */
1243         if (lastpage != NULL || log != NULL) {
1244                 spin_lock_irqsave(&bitmap->lock, flags);
1245                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1246                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1247                         spin_unlock_irqrestore(&bitmap->lock, flags);
1248                         if (lastpage)
1249                                 write_page(bitmap, lastpage, 0);
1250                         else
1251                                 if (log->type->flush(log))
1252                                         bitmap->flags |= BITMAP_WRITE_ERROR;
1253                 } else {
1254                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1255                         spin_unlock_irqrestore(&bitmap->lock, flags);
1256                 }
1257         }
1258
1259  done:
1260         if (bitmap->allclean == 0)
1261                 bitmap->mddev->thread->timeout =
1262                         bitmap->mddev->bitmap_info.daemon_sleep;
1263         mutex_unlock(&mddev->bitmap_info.mutex);
1264 }
1265
1266 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1267                                             sector_t offset, sector_t *blocks,
1268                                             int create)
1269 __releases(bitmap->lock)
1270 __acquires(bitmap->lock)
1271 {
1272         /* If 'create', we might release the lock and reclaim it.
1273          * The lock must have been taken with interrupts enabled.
1274          * If !create, we don't release the lock.
1275          */
1276         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1277         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1278         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1279         sector_t csize;
1280         int err;
1281
1282         err = bitmap_checkpage(bitmap, page, create);
1283
1284         if (bitmap->bp[page].hijacked ||
1285             bitmap->bp[page].map == NULL)
1286                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap) +
1287                                           PAGE_COUNTER_SHIFT - 1);
1288         else
1289                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1290         *blocks = csize - (offset & (csize - 1));
1291
1292         if (err < 0)
1293                 return NULL;
1294
1295         /* now locked ... */
1296
1297         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1298                 /* should we use the first or second counter field
1299                  * of the hijacked pointer? */
1300                 int hi = (pageoff > PAGE_COUNTER_MASK);
1301                 return  &((bitmap_counter_t *)
1302                           &bitmap->bp[page].map)[hi];
1303         } else /* page is allocated */
1304                 return (bitmap_counter_t *)
1305                         &(bitmap->bp[page].map[pageoff]);
1306 }
1307
1308 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1309 {
1310         if (!bitmap)
1311                 return 0;
1312
1313         if (behind) {
1314                 int bw;
1315                 atomic_inc(&bitmap->behind_writes);
1316                 bw = atomic_read(&bitmap->behind_writes);
1317                 if (bw > bitmap->behind_writes_used)
1318                         bitmap->behind_writes_used = bw;
1319
1320                 PRINTK(KERN_DEBUG "inc write-behind count %d/%d\n",
1321                        bw, bitmap->max_write_behind);
1322         }
1323
1324         while (sectors) {
1325                 sector_t blocks;
1326                 bitmap_counter_t *bmc;
1327
1328                 spin_lock_irq(&bitmap->lock);
1329                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 1);
1330                 if (!bmc) {
1331                         spin_unlock_irq(&bitmap->lock);
1332                         return 0;
1333                 }
1334
1335                 if (unlikely((*bmc & COUNTER_MAX) == COUNTER_MAX)) {
1336                         DEFINE_WAIT(__wait);
1337                         /* note that it is safe to do the prepare_to_wait
1338                          * after the test as long as we do it before dropping
1339                          * the spinlock.
1340                          */
1341                         prepare_to_wait(&bitmap->overflow_wait, &__wait,
1342                                         TASK_UNINTERRUPTIBLE);
1343                         spin_unlock_irq(&bitmap->lock);
1344                         io_schedule();
1345                         finish_wait(&bitmap->overflow_wait, &__wait);
1346                         continue;
1347                 }
1348
1349                 switch (*bmc) {
1350                 case 0:
1351                         bitmap_file_set_bit(bitmap, offset);
1352                         bitmap_count_page(bitmap, offset, 1);
1353                         /* fall through */
1354                 case 1:
1355                         *bmc = 2;
1356                 }
1357
1358                 (*bmc)++;
1359
1360                 spin_unlock_irq(&bitmap->lock);
1361
1362                 offset += blocks;
1363                 if (sectors > blocks)
1364                         sectors -= blocks;
1365                 else
1366                         sectors = 0;
1367         }
1368         bitmap->allclean = 0;
1369         return 0;
1370 }
1371 EXPORT_SYMBOL(bitmap_startwrite);
1372
1373 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1374                      int success, int behind)
1375 {
1376         if (!bitmap)
1377                 return;
1378         if (behind) {
1379                 if (atomic_dec_and_test(&bitmap->behind_writes))
1380                         wake_up(&bitmap->behind_wait);
1381                 PRINTK(KERN_DEBUG "dec write-behind count %d/%d\n",
1382                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1383         }
1384         if (bitmap->mddev->degraded)
1385                 /* Never clear bits or update events_cleared when degraded */
1386                 success = 0;
1387
1388         while (sectors) {
1389                 sector_t blocks;
1390                 unsigned long flags;
1391                 bitmap_counter_t *bmc;
1392
1393                 spin_lock_irqsave(&bitmap->lock, flags);
1394                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 0);
1395                 if (!bmc) {
1396                         spin_unlock_irqrestore(&bitmap->lock, flags);
1397                         return;
1398                 }
1399
1400                 if (success &&
1401                     bitmap->events_cleared < bitmap->mddev->events) {
1402                         bitmap->events_cleared = bitmap->mddev->events;
1403                         bitmap->need_sync = 1;
1404                         sysfs_notify_dirent_safe(bitmap->sysfs_can_clear);
1405                 }
1406
1407                 if (!success && ! (*bmc & NEEDED_MASK))
1408                         *bmc |= NEEDED_MASK;
1409
1410                 if ((*bmc & COUNTER_MAX) == COUNTER_MAX)
1411                         wake_up(&bitmap->overflow_wait);
1412
1413                 (*bmc)--;
1414                 if (*bmc <= 2)
1415                         set_page_attr(bitmap,
1416                                       filemap_get_page(
1417                                               bitmap,
1418                                               offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1419                                       BITMAP_PAGE_CLEAN);
1420
1421                 spin_unlock_irqrestore(&bitmap->lock, flags);
1422                 offset += blocks;
1423                 if (sectors > blocks)
1424                         sectors -= blocks;
1425                 else
1426                         sectors = 0;
1427         }
1428 }
1429 EXPORT_SYMBOL(bitmap_endwrite);
1430
1431 static int __bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1432                                int degraded)
1433 {
1434         bitmap_counter_t *bmc;
1435         int rv;
1436         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1437                 *blocks = 1024;
1438                 return 1; /* always resync if no bitmap */
1439         }
1440         spin_lock_irq(&bitmap->lock);
1441         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1442         rv = 0;
1443         if (bmc) {
1444                 /* locked */
1445                 if (RESYNC(*bmc))
1446                         rv = 1;
1447                 else if (NEEDED(*bmc)) {
1448                         rv = 1;
1449                         if (!degraded) { /* don't set/clear bits if degraded */
1450                                 *bmc |= RESYNC_MASK;
1451                                 *bmc &= ~NEEDED_MASK;
1452                         }
1453                 }
1454         }
1455         spin_unlock_irq(&bitmap->lock);
1456         bitmap->allclean = 0;
1457         return rv;
1458 }
1459
1460 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1461                       int degraded)
1462 {
1463         /* bitmap_start_sync must always report on multiples of whole
1464          * pages, otherwise resync (which is very PAGE_SIZE based) will
1465          * get confused.
1466          * So call __bitmap_start_sync repeatedly (if needed) until
1467          * At least PAGE_SIZE>>9 blocks are covered.
1468          * Return the 'or' of the result.
1469          */
1470         int rv = 0;
1471         sector_t blocks1;
1472
1473         *blocks = 0;
1474         while (*blocks < (PAGE_SIZE>>9)) {
1475                 rv |= __bitmap_start_sync(bitmap, offset,
1476                                           &blocks1, degraded);
1477                 offset += blocks1;
1478                 *blocks += blocks1;
1479         }
1480         return rv;
1481 }
1482 EXPORT_SYMBOL(bitmap_start_sync);
1483
1484 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks, int aborted)
1485 {
1486         bitmap_counter_t *bmc;
1487         unsigned long flags;
1488
1489         if (bitmap == NULL) {
1490                 *blocks = 1024;
1491                 return;
1492         }
1493         spin_lock_irqsave(&bitmap->lock, flags);
1494         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1495         if (bmc == NULL)
1496                 goto unlock;
1497         /* locked */
1498         if (RESYNC(*bmc)) {
1499                 *bmc &= ~RESYNC_MASK;
1500
1501                 if (!NEEDED(*bmc) && aborted)
1502                         *bmc |= NEEDED_MASK;
1503                 else {
1504                         if (*bmc <= 2)
1505                                 set_page_attr(bitmap,
1506                                               filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1507                                               BITMAP_PAGE_CLEAN);
1508                 }
1509         }
1510  unlock:
1511         spin_unlock_irqrestore(&bitmap->lock, flags);
1512         bitmap->allclean = 0;
1513 }
1514 EXPORT_SYMBOL(bitmap_end_sync);
1515
1516 void bitmap_close_sync(struct bitmap *bitmap)
1517 {
1518         /* Sync has finished, and any bitmap chunks that weren't synced
1519          * properly have been aborted.  It remains to us to clear the
1520          * RESYNC bit wherever it is still on
1521          */
1522         sector_t sector = 0;
1523         sector_t blocks;
1524         if (!bitmap)
1525                 return;
1526         while (sector < bitmap->mddev->resync_max_sectors) {
1527                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1528                 sector += blocks;
1529         }
1530 }
1531 EXPORT_SYMBOL(bitmap_close_sync);
1532
1533 void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector)
1534 {
1535         sector_t s = 0;
1536         sector_t blocks;
1537
1538         if (!bitmap)
1539                 return;
1540         if (sector == 0) {
1541                 bitmap->last_end_sync = jiffies;
1542                 return;
1543         }
1544         if (time_before(jiffies, (bitmap->last_end_sync
1545                                   + bitmap->mddev->bitmap_info.daemon_sleep)))
1546                 return;
1547         wait_event(bitmap->mddev->recovery_wait,
1548                    atomic_read(&bitmap->mddev->recovery_active) == 0);
1549
1550         bitmap->mddev->curr_resync_completed = sector;
1551         set_bit(MD_CHANGE_CLEAN, &bitmap->mddev->flags);
1552         sector &= ~((1ULL << CHUNK_BLOCK_SHIFT(bitmap)) - 1);
1553         s = 0;
1554         while (s < sector && s < bitmap->mddev->resync_max_sectors) {
1555                 bitmap_end_sync(bitmap, s, &blocks, 0);
1556                 s += blocks;
1557         }
1558         bitmap->last_end_sync = jiffies;
1559         sysfs_notify(&bitmap->mddev->kobj, NULL, "sync_completed");
1560 }
1561 EXPORT_SYMBOL(bitmap_cond_end_sync);
1562
1563 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1564 {
1565         /* For each chunk covered by any of these sectors, set the
1566          * counter to 1 and set resync_needed.  They should all
1567          * be 0 at this point
1568          */
1569
1570         sector_t secs;
1571         bitmap_counter_t *bmc;
1572         spin_lock_irq(&bitmap->lock);
1573         bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
1574         if (!bmc) {
1575                 spin_unlock_irq(&bitmap->lock);
1576                 return;
1577         }
1578         if (!*bmc) {
1579                 struct page *page;
1580                 *bmc = 1 | (needed ? NEEDED_MASK : 0);
1581                 bitmap_count_page(bitmap, offset, 1);
1582                 page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));
1583                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1584         }
1585         spin_unlock_irq(&bitmap->lock);
1586         bitmap->allclean = 0;
1587 }
1588
1589 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
1590 void bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1591 {
1592         unsigned long chunk;
1593
1594         for (chunk = s; chunk <= e; chunk++) {
1595                 sector_t sec = (sector_t)chunk << CHUNK_BLOCK_SHIFT(bitmap);
1596                 bitmap_set_memory_bits(bitmap, sec, 1);
1597                 bitmap_file_set_bit(bitmap, sec);
1598                 if (sec < bitmap->mddev->recovery_cp)
1599                         /* We are asserting that the array is dirty,
1600                          * so move the recovery_cp address back so
1601                          * that it is obvious that it is dirty
1602                          */
1603                         bitmap->mddev->recovery_cp = sec;
1604         }
1605 }
1606
1607 /*
1608  * flush out any pending updates
1609  */
1610 void bitmap_flush(mddev_t *mddev)
1611 {
1612         struct bitmap *bitmap = mddev->bitmap;
1613         long sleep;
1614
1615         if (!bitmap) /* there was no bitmap */
1616                 return;
1617
1618         /* run the daemon_work three time to ensure everything is flushed
1619          * that can be
1620          */
1621         sleep = mddev->bitmap_info.daemon_sleep * 2;
1622         bitmap->daemon_lastrun -= sleep;
1623         bitmap_daemon_work(mddev);
1624         bitmap->daemon_lastrun -= sleep;
1625         bitmap_daemon_work(mddev);
1626         bitmap->daemon_lastrun -= sleep;
1627         bitmap_daemon_work(mddev);
1628         bitmap_update_sb(bitmap);
1629 }
1630
1631 /*
1632  * free memory that was allocated
1633  */
1634 static void bitmap_free(struct bitmap *bitmap)
1635 {
1636         unsigned long k, pages;
1637         struct bitmap_page *bp;
1638
1639         if (!bitmap) /* there was no bitmap */
1640                 return;
1641
1642         /* release the bitmap file and kill the daemon */
1643         bitmap_file_put(bitmap);
1644
1645         bp = bitmap->bp;
1646         pages = bitmap->pages;
1647
1648         /* free all allocated memory */
1649
1650         if (bp) /* deallocate the page memory */
1651                 for (k = 0; k < pages; k++)
1652                         if (bp[k].map && !bp[k].hijacked)
1653                                 kfree(bp[k].map);
1654         kfree(bp);
1655         kfree(bitmap);
1656 }
1657
1658 void bitmap_destroy(mddev_t *mddev)
1659 {
1660         struct bitmap *bitmap = mddev->bitmap;
1661
1662         if (!bitmap) /* there was no bitmap */
1663                 return;
1664
1665         mutex_lock(&mddev->bitmap_info.mutex);
1666         mddev->bitmap = NULL; /* disconnect from the md device */
1667         mutex_unlock(&mddev->bitmap_info.mutex);
1668         if (mddev->thread)
1669                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1670
1671         if (bitmap->sysfs_can_clear)
1672                 sysfs_put(bitmap->sysfs_can_clear);
1673
1674         bitmap_free(bitmap);
1675 }
1676
1677 /*
1678  * initialize the bitmap structure
1679  * if this returns an error, bitmap_destroy must be called to do clean up
1680  */
1681 int bitmap_create(mddev_t *mddev)
1682 {
1683         struct bitmap *bitmap;
1684         sector_t blocks = mddev->resync_max_sectors;
1685         unsigned long chunks;
1686         unsigned long pages;
1687         struct file *file = mddev->bitmap_info.file;
1688         int err;
1689         struct sysfs_dirent *bm = NULL;
1690
1691         BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
1692
1693         if (!file
1694             && !mddev->bitmap_info.offset
1695             && !mddev->bitmap_info.log) /* bitmap disabled, nothing to do */
1696                 return 0;
1697
1698         BUG_ON(file && mddev->bitmap_info.offset);
1699         BUG_ON(mddev->bitmap_info.offset && mddev->bitmap_info.log);
1700
1701         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1702         if (!bitmap)
1703                 return -ENOMEM;
1704
1705         spin_lock_init(&bitmap->lock);
1706         atomic_set(&bitmap->pending_writes, 0);
1707         init_waitqueue_head(&bitmap->write_wait);
1708         init_waitqueue_head(&bitmap->overflow_wait);
1709         init_waitqueue_head(&bitmap->behind_wait);
1710
1711         bitmap->mddev = mddev;
1712
1713         if (mddev->kobj.sd)
1714                 bm = sysfs_get_dirent(mddev->kobj.sd, NULL, "bitmap");
1715         if (bm) {
1716                 bitmap->sysfs_can_clear = sysfs_get_dirent(bm, NULL, "can_clear");
1717                 sysfs_put(bm);
1718         } else
1719                 bitmap->sysfs_can_clear = NULL;
1720
1721         bitmap->file = file;
1722         if (file) {
1723                 get_file(file);
1724                 /* As future accesses to this file will use bmap,
1725                  * and bypass the page cache, we must sync the file
1726                  * first.
1727                  */
1728                 vfs_fsync(file, 1);
1729         }
1730         /* read superblock from bitmap file (this sets mddev->bitmap_info.chunksize) */
1731         if (!mddev->bitmap_info.external)
1732                 err = bitmap_read_sb(bitmap);
1733         else {
1734                 err = 0;
1735                 if (mddev->bitmap_info.chunksize == 0 ||
1736                     mddev->bitmap_info.daemon_sleep == 0)
1737                         /* chunksize and time_base need to be
1738                          * set first. */
1739                         err = -EINVAL;
1740         }
1741         if (err)
1742                 goto error;
1743
1744         bitmap->daemon_lastrun = jiffies;
1745         bitmap->chunkshift = ffz(~mddev->bitmap_info.chunksize);
1746
1747         /* now that chunksize and chunkshift are set, we can use these macros */
1748         chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) >>
1749                         CHUNK_BLOCK_SHIFT(bitmap);
1750         pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
1751
1752         BUG_ON(!pages);
1753
1754         bitmap->chunks = chunks;
1755         bitmap->pages = pages;
1756         bitmap->missing_pages = pages;
1757         bitmap->counter_bits = COUNTER_BITS;
1758
1759         bitmap->syncchunk = ~0UL;
1760
1761 #ifdef INJECT_FATAL_FAULT_1
1762         bitmap->bp = NULL;
1763 #else
1764         bitmap->bp = kzalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
1765 #endif
1766         err = -ENOMEM;
1767         if (!bitmap->bp)
1768                 goto error;
1769
1770         printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
1771                 pages, bmname(bitmap));
1772
1773         mddev->bitmap = bitmap;
1774
1775
1776         return (bitmap->flags & BITMAP_WRITE_ERROR) ? -EIO : 0;
1777
1778  error:
1779         bitmap_free(bitmap);
1780         return err;
1781 }
1782
1783 int bitmap_load(mddev_t *mddev)
1784 {
1785         int err = 0;
1786         sector_t sector = 0;
1787         struct bitmap *bitmap = mddev->bitmap;
1788
1789         if (!bitmap)
1790                 goto out;
1791
1792         /* Clear out old bitmap info first:  Either there is none, or we
1793          * are resuming after someone else has possibly changed things,
1794          * so we should forget old cached info.
1795          * All chunks should be clean, but some might need_sync.
1796          */
1797         while (sector < mddev->resync_max_sectors) {
1798                 sector_t blocks;
1799                 bitmap_start_sync(bitmap, sector, &blocks, 0);
1800                 sector += blocks;
1801         }
1802         bitmap_close_sync(bitmap);
1803
1804         if (mddev->bitmap_info.log) {
1805                 unsigned long i;
1806                 struct dm_dirty_log *log = mddev->bitmap_info.log;
1807                 for (i = 0; i < bitmap->chunks; i++)
1808                         if (!log->type->in_sync(log, i, 1))
1809                                 bitmap_set_memory_bits(bitmap,
1810                                                        (sector_t)i << CHUNK_BLOCK_SHIFT(bitmap),
1811                                                        1);
1812         } else {
1813                 sector_t start = 0;
1814                 if (mddev->degraded == 0
1815                     || bitmap->events_cleared == mddev->events)
1816                         /* no need to keep dirty bits to optimise a
1817                          * re-add of a missing device */
1818                         start = mddev->recovery_cp;
1819
1820                 err = bitmap_init_from_disk(bitmap, start);
1821         }
1822         if (err)
1823                 goto out;
1824
1825         mddev->thread->timeout = mddev->bitmap_info.daemon_sleep;
1826         md_wakeup_thread(mddev->thread);
1827
1828         bitmap_update_sb(bitmap);
1829
1830         if (bitmap->flags & BITMAP_WRITE_ERROR)
1831                 err = -EIO;
1832 out:
1833         return err;
1834 }
1835 EXPORT_SYMBOL_GPL(bitmap_load);
1836
1837 static ssize_t
1838 location_show(mddev_t *mddev, char *page)
1839 {
1840         ssize_t len;
1841         if (mddev->bitmap_info.file)
1842                 len = sprintf(page, "file");
1843         else if (mddev->bitmap_info.offset)
1844                 len = sprintf(page, "%+lld", (long long)mddev->bitmap_info.offset);
1845         else
1846                 len = sprintf(page, "none");
1847         len += sprintf(page+len, "\n");
1848         return len;
1849 }
1850
1851 static ssize_t
1852 location_store(mddev_t *mddev, const char *buf, size_t len)
1853 {
1854
1855         if (mddev->pers) {
1856                 if (!mddev->pers->quiesce)
1857                         return -EBUSY;
1858                 if (mddev->recovery || mddev->sync_thread)
1859                         return -EBUSY;
1860         }
1861
1862         if (mddev->bitmap || mddev->bitmap_info.file ||
1863             mddev->bitmap_info.offset) {
1864                 /* bitmap already configured.  Only option is to clear it */
1865                 if (strncmp(buf, "none", 4) != 0)
1866                         return -EBUSY;
1867                 if (mddev->pers) {
1868                         mddev->pers->quiesce(mddev, 1);
1869                         bitmap_destroy(mddev);
1870                         mddev->pers->quiesce(mddev, 0);
1871                 }
1872                 mddev->bitmap_info.offset = 0;
1873                 if (mddev->bitmap_info.file) {
1874                         struct file *f = mddev->bitmap_info.file;
1875                         mddev->bitmap_info.file = NULL;
1876                         restore_bitmap_write_access(f);
1877                         fput(f);
1878                 }
1879         } else {
1880                 /* No bitmap, OK to set a location */
1881                 long long offset;
1882                 if (strncmp(buf, "none", 4) == 0)
1883                         /* nothing to be done */;
1884                 else if (strncmp(buf, "file:", 5) == 0) {
1885                         /* Not supported yet */
1886                         return -EINVAL;
1887                 } else {
1888                         int rv;
1889                         if (buf[0] == '+')
1890                                 rv = strict_strtoll(buf+1, 10, &offset);
1891                         else
1892                                 rv = strict_strtoll(buf, 10, &offset);
1893                         if (rv)
1894                                 return rv;
1895                         if (offset == 0)
1896                                 return -EINVAL;
1897                         if (mddev->bitmap_info.external == 0 &&
1898                             mddev->major_version == 0 &&
1899                             offset != mddev->bitmap_info.default_offset)
1900                                 return -EINVAL;
1901                         mddev->bitmap_info.offset = offset;
1902                         if (mddev->pers) {
1903                                 mddev->pers->quiesce(mddev, 1);
1904                                 rv = bitmap_create(mddev);
1905                                 if (rv) {
1906                                         bitmap_destroy(mddev);
1907                                         mddev->bitmap_info.offset = 0;
1908                                 }
1909                                 mddev->pers->quiesce(mddev, 0);
1910                                 if (rv)
1911                                         return rv;
1912                         }
1913                 }
1914         }
1915         if (!mddev->external) {
1916                 /* Ensure new bitmap info is stored in
1917                  * metadata promptly.
1918                  */
1919                 set_bit(MD_CHANGE_DEVS, &mddev->flags);
1920                 md_wakeup_thread(mddev->thread);
1921         }
1922         return len;
1923 }
1924
1925 static struct md_sysfs_entry bitmap_location =
1926 __ATTR(location, S_IRUGO|S_IWUSR, location_show, location_store);
1927
1928 static ssize_t
1929 timeout_show(mddev_t *mddev, char *page)
1930 {
1931         ssize_t len;
1932         unsigned long secs = mddev->bitmap_info.daemon_sleep / HZ;
1933         unsigned long jifs = mddev->bitmap_info.daemon_sleep % HZ;
1934
1935         len = sprintf(page, "%lu", secs);
1936         if (jifs)
1937                 len += sprintf(page+len, ".%03u", jiffies_to_msecs(jifs));
1938         len += sprintf(page+len, "\n");
1939         return len;
1940 }
1941
1942 static ssize_t
1943 timeout_store(mddev_t *mddev, const char *buf, size_t len)
1944 {
1945         /* timeout can be set at any time */
1946         unsigned long timeout;
1947         int rv = strict_strtoul_scaled(buf, &timeout, 4);
1948         if (rv)
1949                 return rv;
1950
1951         /* just to make sure we don't overflow... */
1952         if (timeout >= LONG_MAX / HZ)
1953                 return -EINVAL;
1954
1955         timeout = timeout * HZ / 10000;
1956
1957         if (timeout >= MAX_SCHEDULE_TIMEOUT)
1958                 timeout = MAX_SCHEDULE_TIMEOUT-1;
1959         if (timeout < 1)
1960                 timeout = 1;
1961         mddev->bitmap_info.daemon_sleep = timeout;
1962         if (mddev->thread) {
1963                 /* if thread->timeout is MAX_SCHEDULE_TIMEOUT, then
1964                  * the bitmap is all clean and we don't need to
1965                  * adjust the timeout right now
1966                  */
1967                 if (mddev->thread->timeout < MAX_SCHEDULE_TIMEOUT) {
1968                         mddev->thread->timeout = timeout;
1969                         md_wakeup_thread(mddev->thread);
1970                 }
1971         }
1972         return len;
1973 }
1974
1975 static struct md_sysfs_entry bitmap_timeout =
1976 __ATTR(time_base, S_IRUGO|S_IWUSR, timeout_show, timeout_store);
1977
1978 static ssize_t
1979 backlog_show(mddev_t *mddev, char *page)
1980 {
1981         return sprintf(page, "%lu\n", mddev->bitmap_info.max_write_behind);
1982 }
1983
1984 static ssize_t
1985 backlog_store(mddev_t *mddev, const char *buf, size_t len)
1986 {
1987         unsigned long backlog;
1988         int rv = strict_strtoul(buf, 10, &backlog);
1989         if (rv)
1990                 return rv;
1991         if (backlog > COUNTER_MAX)
1992                 return -EINVAL;
1993         mddev->bitmap_info.max_write_behind = backlog;
1994         return len;
1995 }
1996
1997 static struct md_sysfs_entry bitmap_backlog =
1998 __ATTR(backlog, S_IRUGO|S_IWUSR, backlog_show, backlog_store);
1999
2000 static ssize_t
2001 chunksize_show(mddev_t *mddev, char *page)
2002 {
2003         return sprintf(page, "%lu\n", mddev->bitmap_info.chunksize);
2004 }
2005
2006 static ssize_t
2007 chunksize_store(mddev_t *mddev, const char *buf, size_t len)
2008 {
2009         /* Can only be changed when no bitmap is active */
2010         int rv;
2011         unsigned long csize;
2012         if (mddev->bitmap)
2013                 return -EBUSY;
2014         rv = strict_strtoul(buf, 10, &csize);
2015         if (rv)
2016                 return rv;
2017         if (csize < 512 ||
2018             !is_power_of_2(csize))
2019                 return -EINVAL;
2020         mddev->bitmap_info.chunksize = csize;
2021         return len;
2022 }
2023
2024 static struct md_sysfs_entry bitmap_chunksize =
2025 __ATTR(chunksize, S_IRUGO|S_IWUSR, chunksize_show, chunksize_store);
2026
2027 static ssize_t metadata_show(mddev_t *mddev, char *page)
2028 {
2029         return sprintf(page, "%s\n", (mddev->bitmap_info.external
2030                                       ? "external" : "internal"));
2031 }
2032
2033 static ssize_t metadata_store(mddev_t *mddev, const char *buf, size_t len)
2034 {
2035         if (mddev->bitmap ||
2036             mddev->bitmap_info.file ||
2037             mddev->bitmap_info.offset)
2038                 return -EBUSY;
2039         if (strncmp(buf, "external", 8) == 0)
2040                 mddev->bitmap_info.external = 1;
2041         else if (strncmp(buf, "internal", 8) == 0)
2042                 mddev->bitmap_info.external = 0;
2043         else
2044                 return -EINVAL;
2045         return len;
2046 }
2047
2048 static struct md_sysfs_entry bitmap_metadata =
2049 __ATTR(metadata, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
2050
2051 static ssize_t can_clear_show(mddev_t *mddev, char *page)
2052 {
2053         int len;
2054         if (mddev->bitmap)
2055                 len = sprintf(page, "%s\n", (mddev->bitmap->need_sync ?
2056                                              "false" : "true"));
2057         else
2058                 len = sprintf(page, "\n");
2059         return len;
2060 }
2061
2062 static ssize_t can_clear_store(mddev_t *mddev, const char *buf, size_t len)
2063 {
2064         if (mddev->bitmap == NULL)
2065                 return -ENOENT;
2066         if (strncmp(buf, "false", 5) == 0)
2067                 mddev->bitmap->need_sync = 1;
2068         else if (strncmp(buf, "true", 4) == 0) {
2069                 if (mddev->degraded)
2070                         return -EBUSY;
2071                 mddev->bitmap->need_sync = 0;
2072         } else
2073                 return -EINVAL;
2074         return len;
2075 }
2076
2077 static struct md_sysfs_entry bitmap_can_clear =
2078 __ATTR(can_clear, S_IRUGO|S_IWUSR, can_clear_show, can_clear_store);
2079
2080 static ssize_t
2081 behind_writes_used_show(mddev_t *mddev, char *page)
2082 {
2083         if (mddev->bitmap == NULL)
2084                 return sprintf(page, "0\n");
2085         return sprintf(page, "%lu\n",
2086                        mddev->bitmap->behind_writes_used);
2087 }
2088
2089 static ssize_t
2090 behind_writes_used_reset(mddev_t *mddev, const char *buf, size_t len)
2091 {
2092         if (mddev->bitmap)
2093                 mddev->bitmap->behind_writes_used = 0;
2094         return len;
2095 }
2096
2097 static struct md_sysfs_entry max_backlog_used =
2098 __ATTR(max_backlog_used, S_IRUGO | S_IWUSR,
2099        behind_writes_used_show, behind_writes_used_reset);
2100
2101 static struct attribute *md_bitmap_attrs[] = {
2102         &bitmap_location.attr,
2103         &bitmap_timeout.attr,
2104         &bitmap_backlog.attr,
2105         &bitmap_chunksize.attr,
2106         &bitmap_metadata.attr,
2107         &bitmap_can_clear.attr,
2108         &max_backlog_used.attr,
2109         NULL
2110 };
2111 struct attribute_group md_bitmap_group = {
2112         .name = "bitmap",
2113         .attrs = md_bitmap_attrs,
2114 };
2115