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_UNPLUG | 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         }
 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 (sb->state & cpu_to_le32(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                 break;
 656         case MASK_UNSET:
 657                 sb->state &= cpu_to_le32(~bits);
 658                 break;
 659         default:
 660                 BUG();
 661         }
 662         kunmap_atomic(sb, KM_USER0);
 663         return old;
 664 }
 665
 666 /*
 667  * general bitmap file operations
 668  */
 669
 670 /*
 671  * on-disk bitmap:
 672  *
 673  * Use one bit per "chunk" (block set). We do the disk I/O on the bitmap
 674  * file a page at a time. There's a superblock at the start of the file.
 675  */
 676 /* calculate the index of the page that contains this bit */
 677 static inline unsigned long file_page_index(struct bitmap *bitmap, unsigned long chunk)
 678 {
 679         if (!bitmap->mddev->bitmap_info.external)
 680                 chunk += sizeof(bitmap_super_t) << 3;
 681         return chunk >> PAGE_BIT_SHIFT;
 682 }
 683
 684 /* calculate the (bit) offset of this bit within a page */
 685 static inline unsigned long file_page_offset(struct bitmap *bitmap, unsigned long chunk)
 686 {
 687         if (!bitmap->mddev->bitmap_info.external)
 688                 chunk += sizeof(bitmap_super_t) << 3;
 689         return chunk & (PAGE_BITS - 1);
 690 }
 691
 692 /*
 693  * return a pointer to the page in the filemap that contains the given bit
 694  *
 695  * this lookup is complicated by the fact that the bitmap sb might be exactly
 696  * 1 page (e.g., x86) or less than 1 page -- so the bitmap might start on page
 697  * 0 or page 1
 698  */
 699 static inline struct page *filemap_get_page(struct bitmap *bitmap,
 700                                         unsigned long chunk)
 701 {
 702         if (bitmap->filemap == NULL)
 703                 return NULL;
 704         if (file_page_index(bitmap, chunk) >= bitmap->file_pages)
 705                 return NULL;
 706         return bitmap->filemap[file_page_index(bitmap, chunk)
 707                                - file_page_index(bitmap, 0)];
 708 }
 709
 710 static void bitmap_file_unmap(struct bitmap *bitmap)
 711 {
 712         struct page **map, *sb_page;
 713         unsigned long *attr;
 714         int pages;
 715         unsigned long flags;
 716
 717         spin_lock_irqsave(&bitmap->lock, flags);
 718         map = bitmap->filemap;
 719         bitmap->filemap = NULL;
 720         attr = bitmap->filemap_attr;
 721         bitmap->filemap_attr = NULL;
 722         pages = bitmap->file_pages;
 723         bitmap->file_pages = 0;
 724         sb_page = bitmap->sb_page;
 725         bitmap->sb_page = NULL;
 726         spin_unlock_irqrestore(&bitmap->lock, flags);
 727
 728         while (pages--)
 729                 if (map[pages] != sb_page) /* 0 is sb_page, release it below */
 730                         free_buffers(map[pages]);
 731         kfree(map);
 732         kfree(attr);
 733
 734         if (sb_page)
 735                 free_buffers(sb_page);
 736 }
 737
 738 static void bitmap_file_put(struct bitmap *bitmap)
 739 {
 740         struct file *file;
 741         unsigned long flags;
 742
 743         spin_lock_irqsave(&bitmap->lock, flags);
 744         file = bitmap->file;
 745         bitmap->file = NULL;
 746         spin_unlock_irqrestore(&bitmap->lock, flags);
 747
 748         if (file)
 749                 wait_event(bitmap->write_wait,
 750                            atomic_read(&bitmap->pending_writes)==0);
 751         bitmap_file_unmap(bitmap);
 752
 753         if (file) {
 754                 struct inode *inode = file->f_path.dentry->d_inode;
 755                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
 756                 fput(file);
 757         }
 758 }
 759
 760 /*
 761  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
 762  * then it is no longer reliable, so we stop using it and we mark the file
 763  * as failed in the superblock
 764  */
 765 static void bitmap_file_kick(struct bitmap *bitmap)
 766 {
 767         char *path, *ptr = NULL;
 768
 769         if (bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET) == 0) {
 770                 bitmap_update_sb(bitmap);
 771
 772                 if (bitmap->file) {
 773                         path = kmalloc(PAGE_SIZE, GFP_KERNEL);
 774                         if (path)
 775                                 ptr = d_path(&bitmap->file->f_path, path,
 776                                              PAGE_SIZE);
 777
 778                         printk(KERN_ALERT
 779                               "%s: kicking failed bitmap file %s from array!\n",
 780                               bmname(bitmap), IS_ERR(ptr) ? "" : ptr);
 781
 782                         kfree(path);
 783                 } else
 784                         printk(KERN_ALERT
 785                                "%s: disabling internal bitmap due to errors\n",
 786                                bmname(bitmap));
 787         }
 788
 789         bitmap_file_put(bitmap);
 790
 791         return;
 792 }
 793
 794 enum bitmap_page_attr {
 795         BITMAP_PAGE_DIRTY = 0,     /* there are set bits that need to be synced */
 796         BITMAP_PAGE_CLEAN = 1,     /* there are bits that might need to be cleared */
 797         BITMAP_PAGE_NEEDWRITE = 2, /* there are cleared bits that need to be synced */
 798 };
 799
 800 static inline void set_page_attr(struct bitmap *bitmap, struct page *page,
 801                                 enum bitmap_page_attr attr)
 802 {
 803         if (page)
 804                 __set_bit((page->index<<2) + attr, bitmap->filemap_attr);
 805         else
 806                 __set_bit(attr, &bitmap->logattrs);
 807 }
 808
 809 static inline void clear_page_attr(struct bitmap *bitmap, struct page *page,
 810                                 enum bitmap_page_attr attr)
 811 {
 812         if (page)
 813                 __clear_bit((page->index<<2) + attr, bitmap->filemap_attr);
 814         else
 815                 __clear_bit(attr, &bitmap->logattrs);
 816 }
 817
 818 static inline unsigned long test_page_attr(struct bitmap *bitmap, struct page *page,
 819                                            enum bitmap_page_attr attr)
 820 {
 821         if (page)
 822                 return test_bit((page->index<<2) + attr, bitmap->filemap_attr);
 823         else
 824                 return test_bit(attr, &bitmap->logattrs);
 825 }
 826
 827 /*
 828  * bitmap_file_set_bit -- called before performing a write to the md device
 829  * to set (and eventually sync) a particular bit in the bitmap file
 830  *
 831  * we set the bit immediately, then we record the page number so that
 832  * when an unplug occurs, we can flush the dirty pages out to disk
 833  */
 834 static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 835 {
 836         unsigned long bit;
 837         struct page *page = NULL;
 838         void *kaddr;
 839         unsigned long chunk = block >> CHUNK_BLOCK_SHIFT(bitmap);
 840
 841         if (!bitmap->filemap) {
 842                 struct dm_dirty_log *log = bitmap->mddev->bitmap_info.log;
 843                 if (log)
 844                         log->type->mark_region(log, chunk);
 845         } else {
 846
 847                 page = filemap_get_page(bitmap, chunk);
 848                 if (!page)
 849                         return;
 850                 bit = file_page_offset(bitmap, chunk);
 851
 852                 /* set the bit */
 853                 kaddr = kmap_atomic(page, KM_USER0);
 854                 if (bitmap->flags & BITMAP_HOSTENDIAN)
 855                         set_bit(bit, kaddr);
 856                 else
 857                         ext2_set_bit(bit, kaddr);
 858                 kunmap_atomic(kaddr, KM_USER0);
 859                 PRINTK("set file bit %lu page %lu\n", bit, page->index);
 860         }
 861         /* record page number so it gets flushed to disk when unplug occurs */
 862         set_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 863 }
 864
 865 /* this gets called when the md device is ready to unplug its underlying
 866  * (slave) device queues -- before we let any writes go down, we need to
 867  * sync the dirty pages of the bitmap file to disk */
 868 void bitmap_unplug(struct bitmap *bitmap)
 869 {
 870         unsigned long i, flags;
 871         int dirty, need_write;
 872         struct page *page;
 873         int wait = 0;
 874
 875         if (!bitmap)
 876                 return;
 877         if (!bitmap->filemap) {
 878                 /* Must be using a dirty_log */
 879                 struct dm_dirty_log *log = bitmap->mddev->bitmap_info.log;
 880                 dirty = test_and_clear_bit(BITMAP_PAGE_DIRTY, &bitmap->logattrs);
 881                 need_write = test_and_clear_bit(BITMAP_PAGE_NEEDWRITE, &bitmap->logattrs);
 882                 if (dirty || need_write)
 883                         if (log->type->flush(log))
 884                                 bitmap->flags |= BITMAP_WRITE_ERROR;
 885                 goto out;
 886         }
 887
 888         /* look at each page to see if there are any set bits that need to be
 889          * flushed out to disk */
 890         for (i = 0; i < bitmap->file_pages; i++) {
 891                 spin_lock_irqsave(&bitmap->lock, flags);
 892                 if (!bitmap->filemap) {
 893                         spin_unlock_irqrestore(&bitmap->lock, flags);
 894                         return;
 895                 }
 896                 page = bitmap->filemap[i];
 897                 dirty = test_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 898                 need_write = test_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 899                 clear_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 900                 clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 901                 if (dirty)
 902                         wait = 1;
 903                 spin_unlock_irqrestore(&bitmap->lock, flags);
 904
 905                 if (dirty || need_write)
 906                         write_page(bitmap, page, 0);
 907         }
 908         if (wait) { /* if any writes were performed, we need to wait on them */
 909                 if (bitmap->file)
 910                         wait_event(bitmap->write_wait,
 911                                    atomic_read(&bitmap->pending_writes)==0);
 912                 else
 913                         md_super_wait(bitmap->mddev);
 914         }
 915 out:
 916         if (bitmap->flags & BITMAP_WRITE_ERROR)
 917                 bitmap_file_kick(bitmap);
 918 }
 919 EXPORT_SYMBOL(bitmap_unplug);
 920
 921 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
 922 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
 923  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
 924  * memory mapping of the bitmap file
 925  * Special cases:
 926  *   if there's no bitmap file, or if the bitmap file had been
 927  *   previously kicked from the array, we mark all the bits as
 928  *   1's in order to cause a full resync.
 929  *
 930  * We ignore all bits for sectors that end earlier than 'start'.
 931  * This is used when reading an out-of-date bitmap...
 932  */
 933 static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
 934 {
 935         unsigned long i, chunks, index, oldindex, bit;
 936         struct page *page = NULL, *oldpage = NULL;
 937         unsigned long num_pages, bit_cnt = 0;
 938         struct file *file;
 939         unsigned long bytes, offset;
 940         int outofdate;
 941         int ret = -ENOSPC;
 942         void *paddr;
 943
 944         chunks = bitmap->chunks;
 945         file = bitmap->file;
 946
 947         BUG_ON(!file && !bitmap->mddev->bitmap_info.offset);
 948
 949 #ifdef INJECT_FAULTS_3
 950         outofdate = 1;
 951 #else
 952         outofdate = bitmap->flags & BITMAP_STALE;
 953 #endif
 954         if (outofdate)
 955                 printk(KERN_INFO "%s: bitmap file is out of date, doing full "
 956                         "recovery\n", bmname(bitmap));
 957
 958         bytes = DIV_ROUND_UP(bitmap->chunks, 8);
 959         if (!bitmap->mddev->bitmap_info.external)
 960                 bytes += sizeof(bitmap_super_t);
 961
 962         num_pages = DIV_ROUND_UP(bytes, PAGE_SIZE);
 963
 964         if (file && i_size_read(file->f_mapping->host) < bytes) {
 965                 printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
 966                         bmname(bitmap),
 967                         (unsigned long) i_size_read(file->f_mapping->host),
 968                         bytes);
 969                 goto err;
 970         }
 971
 972         ret = -ENOMEM;
 973
 974         bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
 975         if (!bitmap->filemap)
 976                 goto err;
 977
 978         /* We need 4 bits per page, rounded up to a multiple of sizeof(unsigned long) */
 979         bitmap->filemap_attr = kzalloc(
 980                 roundup(DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
 981                 GFP_KERNEL);
 982         if (!bitmap->filemap_attr)
 983                 goto err;
 984
 985         oldindex = ~0L;
 986
 987         for (i = 0; i < chunks; i++) {
 988                 int b;
 989                 index = file_page_index(bitmap, i);
 990                 bit = file_page_offset(bitmap, i);
 991                 if (index != oldindex) { /* this is a new page, read it in */
 992                         int count;
 993                         /* unmap the old page, we're done with it */
 994                         if (index == num_pages-1)
 995                                 count = bytes - index * PAGE_SIZE;
 996                         else
 997                                 count = PAGE_SIZE;
 998                         if (index == 0 && bitmap->sb_page) {
 999                                 /*
1000                                  * if we're here then the superblock page
1001                                  * contains some bits (PAGE_SIZE != sizeof sb)
1002                                  * we've already read it in, so just use it
1003                                  */
1004                                 page = bitmap->sb_page;
1005                                 offset = sizeof(bitmap_super_t);
1006                                 if (!file)
1007                                         page = read_sb_page(
1008                                                 bitmap->mddev,
1009                                                 bitmap->mddev->bitmap_info.offset,
1010                                                 page,
1011                                                 index, count);
1012                         } else if (file) {
1013                                 page = read_page(file, index, bitmap, count);
1014                                 offset = 0;
1015                         } else {
1016                                 page = read_sb_page(bitmap->mddev,
1017                                                     bitmap->mddev->bitmap_info.offset,
1018                                                     NULL,
1019                                                     index, count);
1020                                 offset = 0;
1021                         }
1022                         if (IS_ERR(page)) { /* read error */
1023                                 ret = PTR_ERR(page);
1024                                 goto err;
1025                         }
1026
1027                         oldindex = index;
1028                         oldpage = page;
1029
1030                         bitmap->filemap[bitmap->file_pages++] = page;
1031                         bitmap->last_page_size = count;
1032
1033                         if (outofdate) {
1034                                 /*
1035                                  * if bitmap is out of date, dirty the
1036                                  * whole page and write it out
1037                                  */
1038                                 paddr = kmap_atomic(page, KM_USER0);
1039                                 memset(paddr + offset, 0xff,
1040                                        PAGE_SIZE - offset);
1041                                 kunmap_atomic(paddr, KM_USER0);
1042                                 write_page(bitmap, page, 1);
1043
1044                                 ret = -EIO;
1045                                 if (bitmap->flags & BITMAP_WRITE_ERROR)
1046                                         goto err;
1047                         }
1048                 }
1049                 paddr = kmap_atomic(page, KM_USER0);
1050                 if (bitmap->flags & BITMAP_HOSTENDIAN)
1051                         b = test_bit(bit, paddr);
1052                 else
1053                         b = ext2_test_bit(bit, paddr);
1054                 kunmap_atomic(paddr, KM_USER0);
1055                 if (b) {
1056                         /* if the disk bit is set, set the memory bit */
1057                         int needed = ((sector_t)(i+1) << (CHUNK_BLOCK_SHIFT(bitmap))
1058                                       >= start);
1059                         bitmap_set_memory_bits(bitmap,
1060                                                (sector_t)i << CHUNK_BLOCK_SHIFT(bitmap),
1061                                                needed);
1062                         bit_cnt++;
1063                         set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1064                 }
1065         }
1066
1067         /* everything went OK */
1068         ret = 0;
1069         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_UNSET);
1070
1071         if (bit_cnt) { /* Kick recovery if any bits were set */
1072                 set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
1073                 md_wakeup_thread(bitmap->mddev->thread);
1074         }
1075
1076         printk(KERN_INFO "%s: bitmap initialized from disk: "
1077                 "read %lu/%lu pages, set %lu bits\n",
1078                 bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt);
1079
1080         return 0;
1081
1082  err:
1083         printk(KERN_INFO "%s: bitmap initialisation failed: %d\n",
1084                bmname(bitmap), ret);
1085         return ret;
1086 }
1087
1088 void bitmap_write_all(struct bitmap *bitmap)
1089 {
1090         /* We don't actually write all bitmap blocks here,
1091          * just flag them as needing to be written
1092          */
1093         int i;
1094
1095         for (i = 0; i < bitmap->file_pages; i++)
1096                 set_page_attr(bitmap, bitmap->filemap[i],
1097                               BITMAP_PAGE_NEEDWRITE);
1098 }
1099
1100 static void bitmap_count_page(struct bitmap *bitmap, sector_t offset, int inc)
1101 {
1102         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1103         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1104         bitmap->bp[page].count += inc;
1105         bitmap_checkfree(bitmap, page);
1106 }
1107 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1108                                             sector_t offset, sector_t *blocks,
1109                                             int create);
1110
1111 /*
1112  * bitmap daemon -- periodically wakes up to clean bits and flush pages
1113  *                      out to disk
1114  */
1115
1116 void bitmap_daemon_work(mddev_t *mddev)
1117 {
1118         struct bitmap *bitmap;
1119         unsigned long j;
1120         unsigned long flags;
1121         struct page *page = NULL, *lastpage = NULL;
1122         sector_t blocks;
1123         void *paddr;
1124         struct dm_dirty_log *log = mddev->bitmap_info.log;
1125
1126         /* Use a mutex to guard daemon_work against
1127          * bitmap_destroy.
1128          */
1129         mutex_lock(&mddev->bitmap_info.mutex);
1130         bitmap = mddev->bitmap;
1131         if (bitmap == NULL) {
1132                 mutex_unlock(&mddev->bitmap_info.mutex);
1133                 return;
1134         }
1135         if (time_before(jiffies, bitmap->daemon_lastrun
1136                         + bitmap->mddev->bitmap_info.daemon_sleep))
1137                 goto done;
1138
1139         bitmap->daemon_lastrun = jiffies;
1140         if (bitmap->allclean) {
1141                 bitmap->mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1142                 goto done;
1143         }
1144         bitmap->allclean = 1;
1145
1146         spin_lock_irqsave(&bitmap->lock, flags);
1147         for (j = 0; j < bitmap->chunks; j++) {
1148                 bitmap_counter_t *bmc;
1149                 if (!bitmap->filemap) {
1150                         if (!log)
1151                                 /* error or shutdown */
1152                                 break;
1153                 } else
1154                         page = filemap_get_page(bitmap, j);
1155
1156                 if (page != lastpage) {
1157                         /* skip this page unless it's marked as needing cleaning */
1158                         if (!test_page_attr(bitmap, page, BITMAP_PAGE_CLEAN)) {
1159                                 int need_write = test_page_attr(bitmap, page,
1160                                                                 BITMAP_PAGE_NEEDWRITE);
1161                                 if (need_write)
1162                                         clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
1163
1164                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1165                                 if (need_write) {
1166                                         write_page(bitmap, page, 0);
1167                                         bitmap->allclean = 0;
1168                                 }
1169                                 spin_lock_irqsave(&bitmap->lock, flags);
1170                                 j |= (PAGE_BITS - 1);
1171                                 continue;
1172                         }
1173
1174                         /* grab the new page, sync and release the old */
1175                         if (lastpage != NULL) {
1176                                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1177                                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1178                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1179                                         write_page(bitmap, lastpage, 0);
1180                                 } else {
1181                                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1182                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1183                                 }
1184                         } else
1185                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1186                         lastpage = page;
1187
1188                         /* We are possibly going to clear some bits, so make
1189                          * sure that events_cleared is up-to-date.
1190                          */
1191                         if (bitmap->need_sync &&
1192                             bitmap->mddev->bitmap_info.external == 0) {
1193                                 bitmap_super_t *sb;
1194                                 bitmap->need_sync = 0;
1195                                 sb = kmap_atomic(bitmap->sb_page, KM_USER0);
1196                                 sb->events_cleared =
1197                                         cpu_to_le64(bitmap->events_cleared);
1198                                 kunmap_atomic(sb, KM_USER0);
1199                                 write_page(bitmap, bitmap->sb_page, 1);
1200                         }
1201                         spin_lock_irqsave(&bitmap->lock, flags);
1202                         if (!bitmap->need_sync)
1203                                 clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1204                 }
1205                 bmc = bitmap_get_counter(bitmap,
1206                                          (sector_t)j << CHUNK_BLOCK_SHIFT(bitmap),
1207                                          &blocks, 0);
1208                 if (bmc) {
1209                         if (*bmc)
1210                                 bitmap->allclean = 0;
1211
1212                         if (*bmc == 2) {
1213                                 *bmc = 1; /* maybe clear the bit next time */
1214                                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1215                         } else if (*bmc == 1 && !bitmap->need_sync) {
1216                                 /* we can clear the bit */
1217                                 *bmc = 0;
1218                                 bitmap_count_page(bitmap,
1219                                                   (sector_t)j << CHUNK_BLOCK_SHIFT(bitmap),
1220                                                   -1);
1221
1222                                 /* clear the bit */
1223                                 if (page) {
1224                                         paddr = kmap_atomic(page, KM_USER0);
1225                                         if (bitmap->flags & BITMAP_HOSTENDIAN)
1226                                                 clear_bit(file_page_offset(bitmap, j),
1227                                                           paddr);
1228                                         else
1229                                                 ext2_clear_bit(file_page_offset(bitmap, j),
1230                                                                paddr);
1231                                         kunmap_atomic(paddr, KM_USER0);
1232                                 } else
1233                                         log->type->clear_region(log, j);
1234                         }
1235                 } else
1236                         j |= PAGE_COUNTER_MASK;
1237         }
1238         spin_unlock_irqrestore(&bitmap->lock, flags);
1239
1240         /* now sync the final page */
1241         if (lastpage != NULL || log != NULL) {
1242                 spin_lock_irqsave(&bitmap->lock, flags);
1243                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1244                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1245                         spin_unlock_irqrestore(&bitmap->lock, flags);
1246                         if (lastpage)
1247                                 write_page(bitmap, lastpage, 0);
1248                         else
1249                                 if (log->type->flush(log))
1250                                         bitmap->flags |= BITMAP_WRITE_ERROR;
1251                 } else {
1252                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1253                         spin_unlock_irqrestore(&bitmap->lock, flags);
1254                 }
1255         }
1256
1257  done:
1258         if (bitmap->allclean == 0)
1259                 bitmap->mddev->thread->timeout =
1260                         bitmap->mddev->bitmap_info.daemon_sleep;
1261         mutex_unlock(&mddev->bitmap_info.mutex);
1262 }
1263
1264 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1265                                             sector_t offset, sector_t *blocks,
1266                                             int create)
1267 __releases(bitmap->lock)
1268 __acquires(bitmap->lock)
1269 {
1270         /* If 'create', we might release the lock and reclaim it.
1271          * The lock must have been taken with interrupts enabled.
1272          * If !create, we don't release the lock.
1273          */
1274         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1275         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1276         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1277         sector_t csize;
1278         int err;
1279
1280         err = bitmap_checkpage(bitmap, page, create);
1281
1282         if (bitmap->bp[page].hijacked ||
1283             bitmap->bp[page].map == NULL)
1284                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap) +
1285                                           PAGE_COUNTER_SHIFT - 1);
1286         else
1287                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1288         *blocks = csize - (offset & (csize - 1));
1289
1290         if (err < 0)
1291                 return NULL;
1292
1293         /* now locked ... */
1294
1295         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1296                 /* should we use the first or second counter field
1297                  * of the hijacked pointer? */
1298                 int hi = (pageoff > PAGE_COUNTER_MASK);
1299                 return  &((bitmap_counter_t *)
1300                           &bitmap->bp[page].map)[hi];
1301         } else /* page is allocated */
1302                 return (bitmap_counter_t *)
1303                         &(bitmap->bp[page].map[pageoff]);
1304 }
1305
1306 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1307 {
1308         if (!bitmap)
1309                 return 0;
1310
1311         if (behind) {
1312                 int bw;
1313                 atomic_inc(&bitmap->behind_writes);
1314                 bw = atomic_read(&bitmap->behind_writes);
1315                 if (bw > bitmap->behind_writes_used)
1316                         bitmap->behind_writes_used = bw;
1317
1318                 PRINTK(KERN_DEBUG "inc write-behind count %d/%d\n",
1319                        bw, bitmap->max_write_behind);
1320         }
1321
1322         while (sectors) {
1323                 sector_t blocks;
1324                 bitmap_counter_t *bmc;
1325
1326                 spin_lock_irq(&bitmap->lock);
1327                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 1);
1328                 if (!bmc) {
1329                         spin_unlock_irq(&bitmap->lock);
1330                         return 0;
1331                 }
1332
1333                 if (unlikely((*bmc & COUNTER_MAX) == COUNTER_MAX)) {
1334                         DEFINE_WAIT(__wait);
1335                         /* note that it is safe to do the prepare_to_wait
1336                          * after the test as long as we do it before dropping
1337                          * the spinlock.
1338                          */
1339                         prepare_to_wait(&bitmap->overflow_wait, &__wait,
1340                                         TASK_UNINTERRUPTIBLE);
1341                         spin_unlock_irq(&bitmap->lock);
1342                         md_unplug(bitmap->mddev);
1343                         schedule();
1344                         finish_wait(&bitmap->overflow_wait, &__wait);
1345                         continue;
1346                 }
1347
1348                 switch (*bmc) {
1349                 case 0:
1350                         bitmap_file_set_bit(bitmap, offset);
1351                         bitmap_count_page(bitmap, offset, 1);
1352                         /* fall through */
1353                 case 1:
1354                         *bmc = 2;
1355                 }
1356
1357                 (*bmc)++;
1358
1359                 spin_unlock_irq(&bitmap->lock);
1360
1361                 offset += blocks;
1362                 if (sectors > blocks)
1363                         sectors -= blocks;
1364                 else
1365                         sectors = 0;
1366         }
1367         bitmap->allclean = 0;
1368         return 0;
1369 }
1370 EXPORT_SYMBOL(bitmap_startwrite);
1371
1372 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1373                      int success, int behind)
1374 {
1375         if (!bitmap)
1376                 return;
1377         if (behind) {
1378                 if (atomic_dec_and_test(&bitmap->behind_writes))
1379                         wake_up(&bitmap->behind_wait);
1380                 PRINTK(KERN_DEBUG "dec write-behind count %d/%d\n",
1381                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1382         }
1383         if (bitmap->mddev->degraded)
1384                 /* Never clear bits or update events_cleared when degraded */
1385                 success = 0;
1386
1387         while (sectors) {
1388                 sector_t blocks;
1389                 unsigned long flags;
1390                 bitmap_counter_t *bmc;
1391
1392                 spin_lock_irqsave(&bitmap->lock, flags);
1393                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 0);
1394                 if (!bmc) {
1395                         spin_unlock_irqrestore(&bitmap->lock, flags);
1396                         return;
1397                 }
1398
1399                 if (success &&
1400                     bitmap->events_cleared < bitmap->mddev->events) {
1401                         bitmap->events_cleared = bitmap->mddev->events;
1402                         bitmap->need_sync = 1;
1403                         sysfs_notify_dirent_safe(bitmap->sysfs_can_clear);
1404                 }
1405
1406                 if (!success && ! (*bmc & NEEDED_MASK))
1407                         *bmc |= NEEDED_MASK;
1408
1409                 if ((*bmc & COUNTER_MAX) == COUNTER_MAX)
1410                         wake_up(&bitmap->overflow_wait);
1411
1412                 (*bmc)--;
1413                 if (*bmc <= 2)
1414                         set_page_attr(bitmap,
1415                                       filemap_get_page(
1416                                               bitmap,
1417                                               offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1418                                       BITMAP_PAGE_CLEAN);
1419
1420                 spin_unlock_irqrestore(&bitmap->lock, flags);
1421                 offset += blocks;
1422                 if (sectors > blocks)
1423                         sectors -= blocks;
1424                 else
1425                         sectors = 0;
1426         }
1427 }
1428 EXPORT_SYMBOL(bitmap_endwrite);
1429
1430 static int __bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1431                                int degraded)
1432 {
1433         bitmap_counter_t *bmc;
1434         int rv;
1435         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1436                 *blocks = 1024;
1437                 return 1; /* always resync if no bitmap */
1438         }
1439         spin_lock_irq(&bitmap->lock);
1440         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1441         rv = 0;
1442         if (bmc) {
1443                 /* locked */
1444                 if (RESYNC(*bmc))
1445                         rv = 1;
1446                 else if (NEEDED(*bmc)) {
1447                         rv = 1;
1448                         if (!degraded) { /* don't set/clear bits if degraded */
1449                                 *bmc |= RESYNC_MASK;
1450                                 *bmc &= ~NEEDED_MASK;
1451                         }
1452                 }
1453         }
1454         spin_unlock_irq(&bitmap->lock);
1455         bitmap->allclean = 0;
1456         return rv;
1457 }
1458
1459 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1460                       int degraded)
1461 {
1462         /* bitmap_start_sync must always report on multiples of whole
1463          * pages, otherwise resync (which is very PAGE_SIZE based) will
1464          * get confused.
1465          * So call __bitmap_start_sync repeatedly (if needed) until
1466          * At least PAGE_SIZE>>9 blocks are covered.
1467          * Return the 'or' of the result.
1468          */
1469         int rv = 0;
1470         sector_t blocks1;
1471
1472         *blocks = 0;
1473         while (*blocks < (PAGE_SIZE>>9)) {
1474                 rv |= __bitmap_start_sync(bitmap, offset,
1475                                           &blocks1, degraded);
1476                 offset += blocks1;
1477                 *blocks += blocks1;
1478         }
1479         return rv;
1480 }
1481 EXPORT_SYMBOL(bitmap_start_sync);
1482
1483 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks, int aborted)
1484 {
1485         bitmap_counter_t *bmc;
1486         unsigned long flags;
1487
1488         if (bitmap == NULL) {
1489                 *blocks = 1024;
1490                 return;
1491         }
1492         spin_lock_irqsave(&bitmap->lock, flags);
1493         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1494         if (bmc == NULL)
1495                 goto unlock;
1496         /* locked */
1497         if (RESYNC(*bmc)) {
1498                 *bmc &= ~RESYNC_MASK;
1499
1500                 if (!NEEDED(*bmc) && aborted)
1501                         *bmc |= NEEDED_MASK;
1502                 else {
1503                         if (*bmc <= 2)
1504                                 set_page_attr(bitmap,
1505                                               filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1506                                               BITMAP_PAGE_CLEAN);
1507                 }
1508         }
1509  unlock:
1510         spin_unlock_irqrestore(&bitmap->lock, flags);
1511         bitmap->allclean = 0;
1512 }
1513 EXPORT_SYMBOL(bitmap_end_sync);
1514
1515 void bitmap_close_sync(struct bitmap *bitmap)
1516 {
1517         /* Sync has finished, and any bitmap chunks that weren't synced
1518          * properly have been aborted.  It remains to us to clear the
1519          * RESYNC bit wherever it is still on
1520          */
1521         sector_t sector = 0;
1522         sector_t blocks;
1523         if (!bitmap)
1524                 return;
1525         while (sector < bitmap->mddev->resync_max_sectors) {
1526                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1527                 sector += blocks;
1528         }
1529 }
1530 EXPORT_SYMBOL(bitmap_close_sync);
1531
1532 void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector)
1533 {
1534         sector_t s = 0;
1535         sector_t blocks;
1536
1537         if (!bitmap)
1538                 return;
1539         if (sector == 0) {
1540                 bitmap->last_end_sync = jiffies;
1541                 return;
1542         }
1543         if (time_before(jiffies, (bitmap->last_end_sync
1544                                   + bitmap->mddev->bitmap_info.daemon_sleep)))
1545                 return;
1546         wait_event(bitmap->mddev->recovery_wait,
1547                    atomic_read(&bitmap->mddev->recovery_active) == 0);
1548
1549         bitmap->mddev->curr_resync_completed = sector;
1550         set_bit(MD_CHANGE_CLEAN, &bitmap->mddev->flags);
1551         sector &= ~((1ULL << CHUNK_BLOCK_SHIFT(bitmap)) - 1);
1552         s = 0;
1553         while (s < sector && s < bitmap->mddev->resync_max_sectors) {
1554                 bitmap_end_sync(bitmap, s, &blocks, 0);
1555                 s += blocks;
1556         }
1557         bitmap->last_end_sync = jiffies;
1558         sysfs_notify(&bitmap->mddev->kobj, NULL, "sync_completed");
1559 }
1560 EXPORT_SYMBOL(bitmap_cond_end_sync);
1561
1562 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1563 {
1564         /* For each chunk covered by any of these sectors, set the
1565          * counter to 1 and set resync_needed.  They should all
1566          * be 0 at this point
1567          */
1568
1569         sector_t secs;
1570         bitmap_counter_t *bmc;
1571         spin_lock_irq(&bitmap->lock);
1572         bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
1573         if (!bmc) {
1574                 spin_unlock_irq(&bitmap->lock);
1575                 return;
1576         }
1577         if (!*bmc) {
1578                 struct page *page;
1579                 *bmc = 1 | (needed ? NEEDED_MASK : 0);
1580                 bitmap_count_page(bitmap, offset, 1);
1581                 page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));
1582                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1583         }
1584         spin_unlock_irq(&bitmap->lock);
1585         bitmap->allclean = 0;
1586 }
1587
1588 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
1589 void bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1590 {
1591         unsigned long chunk;
1592
1593         for (chunk = s; chunk <= e; chunk++) {
1594                 sector_t sec = (sector_t)chunk << CHUNK_BLOCK_SHIFT(bitmap);
1595                 bitmap_set_memory_bits(bitmap, sec, 1);
1596                 bitmap_file_set_bit(bitmap, sec);
1597                 if (sec < bitmap->mddev->recovery_cp)
1598                         /* We are asserting that the array is dirty,
1599                          * so move the recovery_cp address back so
1600                          * that it is obvious that it is dirty
1601                          */
1602                         bitmap->mddev->recovery_cp = sec;
1603         }
1604 }
1605
1606 /*
1607  * flush out any pending updates
1608  */
1609 void bitmap_flush(mddev_t *mddev)
1610 {
1611         struct bitmap *bitmap = mddev->bitmap;
1612         long sleep;
1613
1614         if (!bitmap) /* there was no bitmap */
1615                 return;
1616
1617         /* run the daemon_work three time to ensure everything is flushed
1618          * that can be
1619          */
1620         sleep = mddev->bitmap_info.daemon_sleep * 2;
1621         bitmap->daemon_lastrun -= sleep;
1622         bitmap_daemon_work(mddev);
1623         bitmap->daemon_lastrun -= sleep;
1624         bitmap_daemon_work(mddev);
1625         bitmap->daemon_lastrun -= sleep;
1626         bitmap_daemon_work(mddev);
1627         bitmap_update_sb(bitmap);
1628 }
1629
1630 /*
1631  * free memory that was allocated
1632  */
1633 static void bitmap_free(struct bitmap *bitmap)
1634 {
1635         unsigned long k, pages;
1636         struct bitmap_page *bp;
1637
1638         if (!bitmap) /* there was no bitmap */
1639                 return;
1640
1641         /* release the bitmap file and kill the daemon */
1642         bitmap_file_put(bitmap);
1643
1644         bp = bitmap->bp;
1645         pages = bitmap->pages;
1646
1647         /* free all allocated memory */
1648
1649         if (bp) /* deallocate the page memory */
1650                 for (k = 0; k < pages; k++)
1651                         if (bp[k].map && !bp[k].hijacked)
1652                                 kfree(bp[k].map);
1653         kfree(bp);
1654         kfree(bitmap);
1655 }
1656
1657 void bitmap_destroy(mddev_t *mddev)
1658 {
1659         struct bitmap *bitmap = mddev->bitmap;
1660
1661         if (!bitmap) /* there was no bitmap */
1662                 return;
1663
1664         mutex_lock(&mddev->bitmap_info.mutex);
1665         mddev->bitmap = NULL; /* disconnect from the md device */
1666         mutex_unlock(&mddev->bitmap_info.mutex);
1667         if (mddev->thread)
1668                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1669
1670         if (bitmap->sysfs_can_clear)
1671                 sysfs_put(bitmap->sysfs_can_clear);
1672
1673         bitmap_free(bitmap);
1674 }
1675
1676 /*
1677  * initialize the bitmap structure
1678  * if this returns an error, bitmap_destroy must be called to do clean up
1679  */
1680 int bitmap_create(mddev_t *mddev)
1681 {
1682         struct bitmap *bitmap;
1683         sector_t blocks = mddev->resync_max_sectors;
1684         unsigned long chunks;
1685         unsigned long pages;
1686         struct file *file = mddev->bitmap_info.file;
1687         int err;
1688         struct sysfs_dirent *bm = NULL;
1689
1690         BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
1691
1692         if (!file
1693             && !mddev->bitmap_info.offset
1694             && !mddev->bitmap_info.log) /* bitmap disabled, nothing to do */
1695                 return 0;
1696
1697         BUG_ON(file && mddev->bitmap_info.offset);
1698         BUG_ON(mddev->bitmap_info.offset && mddev->bitmap_info.log);
1699
1700         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1701         if (!bitmap)
1702                 return -ENOMEM;
1703
1704         spin_lock_init(&bitmap->lock);
1705         atomic_set(&bitmap->pending_writes, 0);
1706         init_waitqueue_head(&bitmap->write_wait);
1707         init_waitqueue_head(&bitmap->overflow_wait);
1708         init_waitqueue_head(&bitmap->behind_wait);
1709
1710         bitmap->mddev = mddev;
1711
1712         if (mddev->kobj.sd)
1713                 bm = sysfs_get_dirent(mddev->kobj.sd, NULL, "bitmap");
1714         if (bm) {
1715                 bitmap->sysfs_can_clear = sysfs_get_dirent(bm, NULL, "can_clear");
1716                 sysfs_put(bm);
1717         } else
1718                 bitmap->sysfs_can_clear = NULL;
1719
1720         bitmap->file = file;
1721         if (file) {
1722                 get_file(file);
1723                 /* As future accesses to this file will use bmap,
1724                  * and bypass the page cache, we must sync the file
1725                  * first.
1726                  */
1727                 vfs_fsync(file, 1);
1728         }
1729         /* read superblock from bitmap file (this sets mddev->bitmap_info.chunksize) */
1730         if (!mddev->bitmap_info.external)
1731                 err = bitmap_read_sb(bitmap);
1732         else {
1733                 err = 0;
1734                 if (mddev->bitmap_info.chunksize == 0 ||
1735                     mddev->bitmap_info.daemon_sleep == 0)
1736                         /* chunksize and time_base need to be
1737                          * set first. */
1738                         err = -EINVAL;
1739         }
1740         if (err)
1741                 goto error;
1742
1743         bitmap->daemon_lastrun = jiffies;
1744         bitmap->chunkshift = ffz(~mddev->bitmap_info.chunksize);
1745
1746         /* now that chunksize and chunkshift are set, we can use these macros */
1747         chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) >>
1748                         CHUNK_BLOCK_SHIFT(bitmap);
1749         pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
1750
1751         BUG_ON(!pages);
1752
1753         bitmap->chunks = chunks;
1754         bitmap->pages = pages;
1755         bitmap->missing_pages = pages;
1756         bitmap->counter_bits = COUNTER_BITS;
1757
1758         bitmap->syncchunk = ~0UL;
1759
1760 #ifdef INJECT_FATAL_FAULT_1
1761         bitmap->bp = NULL;
1762 #else
1763         bitmap->bp = kzalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
1764 #endif
1765         err = -ENOMEM;
1766         if (!bitmap->bp)
1767                 goto error;
1768
1769         printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
1770                 pages, bmname(bitmap));
1771
1772         mddev->bitmap = bitmap;
1773
1774
1775         return (bitmap->flags & BITMAP_WRITE_ERROR) ? -EIO : 0;
1776
1777  error:
1778         bitmap_free(bitmap);
1779         return err;
1780 }
1781
1782 int bitmap_load(mddev_t *mddev)
1783 {
1784         int err = 0;
1785         sector_t sector = 0;
1786         struct bitmap *bitmap = mddev->bitmap;
1787
1788         if (!bitmap)
1789                 goto out;
1790
1791         /* Clear out old bitmap info first:  Either there is none, or we
1792          * are resuming after someone else has possibly changed things,
1793          * so we should forget old cached info.
1794          * All chunks should be clean, but some might need_sync.
1795          */
1796         while (sector < mddev->resync_max_sectors) {
1797                 sector_t blocks;
1798                 bitmap_start_sync(bitmap, sector, &blocks, 0);
1799                 sector += blocks;
1800         }
1801         bitmap_close_sync(bitmap);
1802
1803         if (mddev->bitmap_info.log) {
1804                 unsigned long i;
1805                 struct dm_dirty_log *log = mddev->bitmap_info.log;
1806                 for (i = 0; i < bitmap->chunks; i++)
1807                         if (!log->type->in_sync(log, i, 1))
1808                                 bitmap_set_memory_bits(bitmap,
1809                                                        (sector_t)i << CHUNK_BLOCK_SHIFT(bitmap),
1810                                                        1);
1811         } else {
1812                 sector_t start = 0;
1813                 if (mddev->degraded == 0
1814                     || bitmap->events_cleared == mddev->events)
1815                         /* no need to keep dirty bits to optimise a
1816                          * re-add of a missing device */
1817                         start = mddev->recovery_cp;
1818
1819                 err = bitmap_init_from_disk(bitmap, start);
1820         }
1821         if (err)
1822                 goto out;
1823
1824         mddev->thread->timeout = mddev->bitmap_info.daemon_sleep;
1825         md_wakeup_thread(mddev->thread);
1826
1827         bitmap_update_sb(bitmap);
1828
1829         if (bitmap->flags & BITMAP_WRITE_ERROR)
1830                 err = -EIO;
1831 out:
1832         return err;
1833 }
1834 EXPORT_SYMBOL_GPL(bitmap_load);
1835
1836 static ssize_t
1837 location_show(mddev_t *mddev, char *page)
1838 {
1839         ssize_t len;
1840         if (mddev->bitmap_info.file)
1841                 len = sprintf(page, "file");
1842         else if (mddev->bitmap_info.offset)
1843                 len = sprintf(page, "%+lld", (long long)mddev->bitmap_info.offset);
1844         else
1845                 len = sprintf(page, "none");
1846         len += sprintf(page+len, "\n");
1847         return len;
1848 }
1849
1850 static ssize_t
1851 location_store(mddev_t *mddev, const char *buf, size_t len)
1852 {
1853
1854         if (mddev->pers) {
1855                 if (!mddev->pers->quiesce)
1856                         return -EBUSY;
1857                 if (mddev->recovery || mddev->sync_thread)
1858                         return -EBUSY;
1859         }
1860
1861         if (mddev->bitmap || mddev->bitmap_info.file ||
1862             mddev->bitmap_info.offset) {
1863                 /* bitmap already configured.  Only option is to clear it */
1864                 if (strncmp(buf, "none", 4) != 0)
1865                         return -EBUSY;
1866                 if (mddev->pers) {
1867                         mddev->pers->quiesce(mddev, 1);
1868                         bitmap_destroy(mddev);
1869                         mddev->pers->quiesce(mddev, 0);
1870                 }
1871                 mddev->bitmap_info.offset = 0;
1872                 if (mddev->bitmap_info.file) {
1873                         struct file *f = mddev->bitmap_info.file;
1874                         mddev->bitmap_info.file = NULL;
1875                         restore_bitmap_write_access(f);
1876                         fput(f);
1877                 }
1878         } else {
1879                 /* No bitmap, OK to set a location */
1880                 long long offset;
1881                 if (strncmp(buf, "none", 4) == 0)
1882                         /* nothing to be done */;
1883                 else if (strncmp(buf, "file:", 5) == 0) {
1884                         /* Not supported yet */
1885                         return -EINVAL;
1886                 } else {
1887                         int rv;
1888                         if (buf[0] == '+')
1889                                 rv = strict_strtoll(buf+1, 10, &offset);
1890                         else
1891                                 rv = strict_strtoll(buf, 10, &offset);
1892                         if (rv)
1893                                 return rv;
1894                         if (offset == 0)
1895                                 return -EINVAL;
1896                         if (mddev->bitmap_info.external == 0 &&
1897                             mddev->major_version == 0 &&
1898                             offset != mddev->bitmap_info.default_offset)
1899                                 return -EINVAL;
1900                         mddev->bitmap_info.offset = offset;
1901                         if (mddev->pers) {
1902                                 mddev->pers->quiesce(mddev, 1);
1903                                 rv = bitmap_create(mddev);
1904                                 if (rv) {
1905                                         bitmap_destroy(mddev);
1906                                         mddev->bitmap_info.offset = 0;
1907                                 }
1908                                 mddev->pers->quiesce(mddev, 0);
1909                                 if (rv)
1910                                         return rv;
1911                         }
1912                 }
1913         }
1914         if (!mddev->external) {
1915                 /* Ensure new bitmap info is stored in
1916                  * metadata promptly.
1917                  */
1918                 set_bit(MD_CHANGE_DEVS, &mddev->flags);
1919                 md_wakeup_thread(mddev->thread);
1920         }
1921         return len;
1922 }
1923
1924 static struct md_sysfs_entry bitmap_location =
1925 __ATTR(location, S_IRUGO|S_IWUSR, location_show, location_store);
1926
1927 static ssize_t
1928 timeout_show(mddev_t *mddev, char *page)
1929 {
1930         ssize_t len;
1931         unsigned long secs = mddev->bitmap_info.daemon_sleep / HZ;
1932         unsigned long jifs = mddev->bitmap_info.daemon_sleep % HZ;
1933
1934         len = sprintf(page, "%lu", secs);
1935         if (jifs)
1936                 len += sprintf(page+len, ".%03u", jiffies_to_msecs(jifs));
1937         len += sprintf(page+len, "\n");
1938         return len;
1939 }
1940
1941 static ssize_t
1942 timeout_store(mddev_t *mddev, const char *buf, size_t len)
1943 {
1944         /* timeout can be set at any time */
1945         unsigned long timeout;
1946         int rv = strict_strtoul_scaled(buf, &timeout, 4);
1947         if (rv)
1948                 return rv;
1949
1950         /* just to make sure we don't overflow... */
1951         if (timeout >= LONG_MAX / HZ)
1952                 return -EINVAL;
1953
1954         timeout = timeout * HZ / 10000;
1955
1956         if (timeout >= MAX_SCHEDULE_TIMEOUT)
1957                 timeout = MAX_SCHEDULE_TIMEOUT-1;
1958         if (timeout < 1)
1959                 timeout = 1;
1960         mddev->bitmap_info.daemon_sleep = timeout;
1961         if (mddev->thread) {
1962                 /* if thread->timeout is MAX_SCHEDULE_TIMEOUT, then
1963                  * the bitmap is all clean and we don't need to
1964                  * adjust the timeout right now
1965                  */
1966                 if (mddev->thread->timeout < MAX_SCHEDULE_TIMEOUT) {
1967                         mddev->thread->timeout = timeout;
1968                         md_wakeup_thread(mddev->thread);
1969                 }
1970         }
1971         return len;
1972 }
1973
1974 static struct md_sysfs_entry bitmap_timeout =
1975 __ATTR(time_base, S_IRUGO|S_IWUSR, timeout_show, timeout_store);
1976
1977 static ssize_t
1978 backlog_show(mddev_t *mddev, char *page)
1979 {
1980         return sprintf(page, "%lu\n", mddev->bitmap_info.max_write_behind);
1981 }
1982
1983 static ssize_t
1984 backlog_store(mddev_t *mddev, const char *buf, size_t len)
1985 {
1986         unsigned long backlog;
1987         int rv = strict_strtoul(buf, 10, &backlog);
1988         if (rv)
1989                 return rv;
1990         if (backlog > COUNTER_MAX)
1991                 return -EINVAL;
1992         mddev->bitmap_info.max_write_behind = backlog;
1993         return len;
1994 }
1995
1996 static struct md_sysfs_entry bitmap_backlog =
1997 __ATTR(backlog, S_IRUGO|S_IWUSR, backlog_show, backlog_store);
1998
1999 static ssize_t
2000 chunksize_show(mddev_t *mddev, char *page)
2001 {
2002         return sprintf(page, "%lu\n", mddev->bitmap_info.chunksize);
2003 }
2004
2005 static ssize_t
2006 chunksize_store(mddev_t *mddev, const char *buf, size_t len)
2007 {
2008         /* Can only be changed when no bitmap is active */
2009         int rv;
2010         unsigned long csize;
2011         if (mddev->bitmap)
2012                 return -EBUSY;
2013         rv = strict_strtoul(buf, 10, &csize);
2014         if (rv)
2015                 return rv;
2016         if (csize < 512 ||
2017             !is_power_of_2(csize))
2018                 return -EINVAL;
2019         mddev->bitmap_info.chunksize = csize;
2020         return len;
2021 }
2022
2023 static struct md_sysfs_entry bitmap_chunksize =
2024 __ATTR(chunksize, S_IRUGO|S_IWUSR, chunksize_show, chunksize_store);
2025
2026 static ssize_t metadata_show(mddev_t *mddev, char *page)
2027 {
2028         return sprintf(page, "%s\n", (mddev->bitmap_info.external
2029                                       ? "external" : "internal"));
2030 }
2031
2032 static ssize_t metadata_store(mddev_t *mddev, const char *buf, size_t len)
2033 {
2034         if (mddev->bitmap ||
2035             mddev->bitmap_info.file ||
2036             mddev->bitmap_info.offset)
2037                 return -EBUSY;
2038         if (strncmp(buf, "external", 8) == 0)
2039                 mddev->bitmap_info.external = 1;
2040         else if (strncmp(buf, "internal", 8) == 0)
2041                 mddev->bitmap_info.external = 0;
2042         else
2043                 return -EINVAL;
2044         return len;
2045 }
2046
2047 static struct md_sysfs_entry bitmap_metadata =
2048 __ATTR(metadata, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
2049
2050 static ssize_t can_clear_show(mddev_t *mddev, char *page)
2051 {
2052         int len;
2053         if (mddev->bitmap)
2054                 len = sprintf(page, "%s\n", (mddev->bitmap->need_sync ?
2055                                              "false" : "true"));
2056         else
2057                 len = sprintf(page, "\n");
2058         return len;
2059 }
2060
2061 static ssize_t can_clear_store(mddev_t *mddev, const char *buf, size_t len)
2062 {
2063         if (mddev->bitmap == NULL)
2064                 return -ENOENT;
2065         if (strncmp(buf, "false", 5) == 0)
2066                 mddev->bitmap->need_sync = 1;
2067         else if (strncmp(buf, "true", 4) == 0) {
2068                 if (mddev->degraded)
2069                         return -EBUSY;
2070                 mddev->bitmap->need_sync = 0;
2071         } else
2072                 return -EINVAL;
2073         return len;
2074 }
2075
2076 static struct md_sysfs_entry bitmap_can_clear =
2077 __ATTR(can_clear, S_IRUGO|S_IWUSR, can_clear_show, can_clear_store);
2078
2079 static ssize_t
2080 behind_writes_used_show(mddev_t *mddev, char *page)
2081 {
2082         if (mddev->bitmap == NULL)
2083                 return sprintf(page, "0\n");
2084         return sprintf(page, "%lu\n",
2085                        mddev->bitmap->behind_writes_used);
2086 }
2087
2088 static ssize_t
2089 behind_writes_used_reset(mddev_t *mddev, const char *buf, size_t len)
2090 {
2091         if (mddev->bitmap)
2092                 mddev->bitmap->behind_writes_used = 0;
2093         return len;
2094 }
2095
2096 static struct md_sysfs_entry max_backlog_used =
2097 __ATTR(max_backlog_used, S_IRUGO | S_IWUSR,
2098        behind_writes_used_show, behind_writes_used_reset);
2099
2100 static struct attribute *md_bitmap_attrs[] = {
2101         &bitmap_location.attr,
2102         &bitmap_timeout.attr,
2103         &bitmap_backlog.attr,
2104         &bitmap_chunksize.attr,
2105         &bitmap_metadata.attr,
2106         &bitmap_can_clear.attr,
2107         &max_backlog_used.attr,
2108         NULL
2109 };
2110 struct attribute_group md_bitmap_group = {
2111         .name = "bitmap",
2112         .attrs = md_bitmap_attrs,
2113 };
2114