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 = rdev->sb_start + offset + index * (PAGE_SIZE/512);
 214
 215                 if (sync_page_io(rdev->bdev, target,
 216                                  roundup(size, bdev_logical_block_size(rdev->bdev)),
 217                                  page, READ)) {
 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         mddev_t *mddev = bitmap->mddev;
 268
 269         while ((rdev = next_active_rdev(rdev, mddev)) != NULL) {
 270                 int size = PAGE_SIZE;
 271                 loff_t offset = mddev->bitmap_info.offset;
 272                 if (page->index == bitmap->file_pages-1)
 273                         size = roundup(bitmap->last_page_size,
 274                                        bdev_logical_block_size(rdev->bdev));
 275                 /* Just make sure we aren't corrupting data or
 276                  * metadata
 277                  */
 278                 if (mddev->external) {
 279                         /* Bitmap could be anywhere. */
 280                         if (rdev->sb_start + offset + (page->index
 281                                                        * (PAGE_SIZE/512))
 282                             > rdev->data_offset
 283                             &&
 284                             rdev->sb_start + offset
 285                             < (rdev->data_offset + mddev->dev_sectors
 286                              + (PAGE_SIZE/512)))
 287                                 goto bad_alignment;
 288                 } else if (offset < 0) {
 289                         /* DATA  BITMAP METADATA  */
 290                         if (offset
 291                             + (long)(page->index * (PAGE_SIZE/512))
 292                             + size/512 > 0)
 293                                 /* bitmap runs in to metadata */
 294                                 goto bad_alignment;
 295                         if (rdev->data_offset + mddev->dev_sectors
 296                             > rdev->sb_start + offset)
 297                                 /* data runs in to bitmap */
 298                                 goto bad_alignment;
 299                 } else if (rdev->sb_start < rdev->data_offset) {
 300                         /* METADATA BITMAP DATA */
 301                         if (rdev->sb_start
 302                             + offset
 303                             + page->index*(PAGE_SIZE/512) + size/512
 304                             > rdev->data_offset)
 305                                 /* bitmap runs in to data */
 306                                 goto bad_alignment;
 307                 } else {
 308                         /* DATA METADATA BITMAP - no problems */
 309                 }
 310                 md_super_write(mddev, rdev,
 311                                rdev->sb_start + offset
 312                                + page->index * (PAGE_SIZE/512),
 313                                size,
 314                                page);
 315         }
 316
 317         if (wait)
 318                 md_super_wait(mddev);
 319         return 0;
 320
 321  bad_alignment:
 322         return -EINVAL;
 323 }
 324
 325 static void bitmap_file_kick(struct bitmap *bitmap);
 326 /*
 327  * write out a page to a file
 328  */
 329 static void write_page(struct bitmap *bitmap, struct page *page, int wait)
 330 {
 331         struct buffer_head *bh;
 332
 333         if (bitmap->file == NULL) {
 334                 switch (write_sb_page(bitmap, page, wait)) {
 335                 case -EINVAL:
 336                         bitmap->flags |= BITMAP_WRITE_ERROR;
 337                 }
 338         } else {
 339
 340                 bh = page_buffers(page);
 341
 342                 while (bh && bh->b_blocknr) {
 343                         atomic_inc(&bitmap->pending_writes);
 344                         set_buffer_locked(bh);
 345                         set_buffer_mapped(bh);
 346                         submit_bh(WRITE, bh);
 347                         bh = bh->b_this_page;
 348                 }
 349
 350                 if (wait)
 351                         wait_event(bitmap->write_wait,
 352                                    atomic_read(&bitmap->pending_writes)==0);
 353         }
 354         if (bitmap->flags & BITMAP_WRITE_ERROR)
 355                 bitmap_file_kick(bitmap);
 356 }
 357
 358 static void end_bitmap_write(struct buffer_head *bh, int uptodate)
 359 {
 360         struct bitmap *bitmap = bh->b_private;
 361         unsigned long flags;
 362
 363         if (!uptodate) {
 364                 spin_lock_irqsave(&bitmap->lock, flags);
 365                 bitmap->flags |= BITMAP_WRITE_ERROR;
 366                 spin_unlock_irqrestore(&bitmap->lock, flags);
 367         }
 368         if (atomic_dec_and_test(&bitmap->pending_writes))
 369                 wake_up(&bitmap->write_wait);
 370 }
 371
 372 /* copied from buffer.c */
 373 static void
 374 __clear_page_buffers(struct page *page)
 375 {
 376         ClearPagePrivate(page);
 377         set_page_private(page, 0);
 378         page_cache_release(page);
 379 }
 380 static void free_buffers(struct page *page)
 381 {
 382         struct buffer_head *bh = page_buffers(page);
 383
 384         while (bh) {
 385                 struct buffer_head *next = bh->b_this_page;
 386                 free_buffer_head(bh);
 387                 bh = next;
 388         }
 389         __clear_page_buffers(page);
 390         put_page(page);
 391 }
 392
 393 /* read a page from a file.
 394  * We both read the page, and attach buffers to the page to record the
 395  * address of each block (using bmap).  These addresses will be used
 396  * to write the block later, completely bypassing the filesystem.
 397  * This usage is similar to how swap files are handled, and allows us
 398  * to write to a file with no concerns of memory allocation failing.
 399  */
 400 static struct page *read_page(struct file *file, unsigned long index,
 401                               struct bitmap *bitmap,
 402                               unsigned long count)
 403 {
 404         struct page *page = NULL;
 405         struct inode *inode = file->f_path.dentry->d_inode;
 406         struct buffer_head *bh;
 407         sector_t block;
 408
 409         PRINTK("read bitmap file (%dB @ %llu)\n", (int)PAGE_SIZE,
 410                         (unsigned long long)index << PAGE_SHIFT);
 411
 412         page = alloc_page(GFP_KERNEL);
 413         if (!page)
 414                 page = ERR_PTR(-ENOMEM);
 415         if (IS_ERR(page))
 416                 goto out;
 417
 418         bh = alloc_page_buffers(page, 1<<inode->i_blkbits, 0);
 419         if (!bh) {
 420                 put_page(page);
 421                 page = ERR_PTR(-ENOMEM);
 422                 goto out;
 423         }
 424         attach_page_buffers(page, bh);
 425         block = index << (PAGE_SHIFT - inode->i_blkbits);
 426         while (bh) {
 427                 if (count == 0)
 428                         bh->b_blocknr = 0;
 429                 else {
 430                         bh->b_blocknr = bmap(inode, block);
 431                         if (bh->b_blocknr == 0) {
 432                                 /* Cannot use this file! */
 433                                 free_buffers(page);
 434                                 page = ERR_PTR(-EINVAL);
 435                                 goto out;
 436                         }
 437                         bh->b_bdev = inode->i_sb->s_bdev;
 438                         if (count < (1<<inode->i_blkbits))
 439                                 count = 0;
 440                         else
 441                                 count -= (1<<inode->i_blkbits);
 442
 443                         bh->b_end_io = end_bitmap_write;
 444                         bh->b_private = bitmap;
 445                         atomic_inc(&bitmap->pending_writes);
 446                         set_buffer_locked(bh);
 447                         set_buffer_mapped(bh);
 448                         submit_bh(READ, bh);
 449                 }
 450                 block++;
 451                 bh = bh->b_this_page;
 452         }
 453         page->index = index;
 454
 455         wait_event(bitmap->write_wait,
 456                    atomic_read(&bitmap->pending_writes)==0);
 457         if (bitmap->flags & BITMAP_WRITE_ERROR) {
 458                 free_buffers(page);
 459                 page = ERR_PTR(-EIO);
 460         }
 461 out:
 462         if (IS_ERR(page))
 463                 printk(KERN_ALERT "md: bitmap read error: (%dB @ %llu): %ld\n",
 464                         (int)PAGE_SIZE,
 465                         (unsigned long long)index << PAGE_SHIFT,
 466                         PTR_ERR(page));
 467         return page;
 468 }
 469
 470 /*
 471  * bitmap file superblock operations
 472  */
 473
 474 /* update the event counter and sync the superblock to disk */
 475 void bitmap_update_sb(struct bitmap *bitmap)
 476 {
 477         bitmap_super_t *sb;
 478         unsigned long flags;
 479
 480         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
 481                 return;
 482         if (bitmap->mddev->bitmap_info.external)
 483                 return;
 484         spin_lock_irqsave(&bitmap->lock, flags);
 485         if (!bitmap->sb_page) { /* no superblock */
 486                 spin_unlock_irqrestore(&bitmap->lock, flags);
 487                 return;
 488         }
 489         spin_unlock_irqrestore(&bitmap->lock, flags);
 490         sb = kmap_atomic(bitmap->sb_page, KM_USER0);
 491         sb->events = cpu_to_le64(bitmap->mddev->events);
 492         if (bitmap->mddev->events < bitmap->events_cleared) {
 493                 /* rocking back to read-only */
 494                 bitmap->events_cleared = bitmap->mddev->events;
 495                 sb->events_cleared = cpu_to_le64(bitmap->events_cleared);
 496         }
 497         /* Just in case these have been changed via sysfs: */
 498         sb->daemon_sleep = cpu_to_le32(bitmap->mddev->bitmap_info.daemon_sleep/HZ);
 499         sb->write_behind = cpu_to_le32(bitmap->mddev->bitmap_info.max_write_behind);
 500         kunmap_atomic(sb, KM_USER0);
 501         write_page(bitmap, bitmap->sb_page, 1);
 502 }
 503
 504 /* print out the bitmap file superblock */
 505 void bitmap_print_sb(struct bitmap *bitmap)
 506 {
 507         bitmap_super_t *sb;
 508
 509         if (!bitmap || !bitmap->sb_page)
 510                 return;
 511         sb = kmap_atomic(bitmap->sb_page, KM_USER0);
 512         printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
 513         printk(KERN_DEBUG "         magic: %08x\n", le32_to_cpu(sb->magic));
 514         printk(KERN_DEBUG "       version: %d\n", le32_to_cpu(sb->version));
 515         printk(KERN_DEBUG "          uuid: %08x.%08x.%08x.%08x\n",
 516                                         *(__u32 *)(sb->uuid+0),
 517                                         *(__u32 *)(sb->uuid+4),
 518                                         *(__u32 *)(sb->uuid+8),
 519                                         *(__u32 *)(sb->uuid+12));
 520         printk(KERN_DEBUG "        events: %llu\n",
 521                         (unsigned long long) le64_to_cpu(sb->events));
 522         printk(KERN_DEBUG "events cleared: %llu\n",
 523                         (unsigned long long) le64_to_cpu(sb->events_cleared));
 524         printk(KERN_DEBUG "         state: %08x\n", le32_to_cpu(sb->state));
 525         printk(KERN_DEBUG "     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
 526         printk(KERN_DEBUG "  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
 527         printk(KERN_DEBUG "     sync size: %llu KB\n",
 528                         (unsigned long long)le64_to_cpu(sb->sync_size)/2);
 529         printk(KERN_DEBUG "max write behind: %d\n", le32_to_cpu(sb->write_behind));
 530         kunmap_atomic(sb, KM_USER0);
 531 }
 532
 533 /* read the superblock from the bitmap file and initialize some bitmap fields */
 534 static int bitmap_read_sb(struct bitmap *bitmap)
 535 {
 536         char *reason = NULL;
 537         bitmap_super_t *sb;
 538         unsigned long chunksize, daemon_sleep, write_behind;
 539         unsigned long long events;
 540         int err = -EINVAL;
 541
 542         /* page 0 is the superblock, read it... */
 543         if (bitmap->file) {
 544                 loff_t isize = i_size_read(bitmap->file->f_mapping->host);
 545                 int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
 546
 547                 bitmap->sb_page = read_page(bitmap->file, 0, bitmap, bytes);
 548         } else {
 549                 bitmap->sb_page = read_sb_page(bitmap->mddev,
 550                                                bitmap->mddev->bitmap_info.offset,
 551                                                NULL,
 552                                                0, sizeof(bitmap_super_t));
 553         }
 554         if (IS_ERR(bitmap->sb_page)) {
 555                 err = PTR_ERR(bitmap->sb_page);
 556                 bitmap->sb_page = NULL;
 557                 return err;
 558         }
 559
 560         sb = kmap_atomic(bitmap->sb_page, KM_USER0);
 561
 562         chunksize = le32_to_cpu(sb->chunksize);
 563         daemon_sleep = le32_to_cpu(sb->daemon_sleep) * HZ;
 564         write_behind = le32_to_cpu(sb->write_behind);
 565
 566         /* verify that the bitmap-specific fields are valid */
 567         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
 568                 reason = "bad magic";
 569         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
 570                  le32_to_cpu(sb->version) > BITMAP_MAJOR_HI)
 571                 reason = "unrecognized superblock version";
 572         else if (chunksize < 512)
 573                 reason = "bitmap chunksize too small";
 574         else if ((1 << ffz(~chunksize)) != chunksize)
 575                 reason = "bitmap chunksize not a power of 2";
 576         else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT)
 577                 reason = "daemon sleep period out of range";
 578         else if (write_behind > COUNTER_MAX)
 579                 reason = "write-behind limit out of range (0 - 16383)";
 580         if (reason) {
 581                 printk(KERN_INFO "%s: invalid bitmap file superblock: %s\n",
 582                         bmname(bitmap), reason);
 583                 goto out;
 584         }
 585
 586         /* keep the array size field of the bitmap superblock up to date */
 587         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 588
 589         if (!bitmap->mddev->persistent)
 590                 goto success;
 591
 592         /*
 593          * if we have a persistent array superblock, compare the
 594          * bitmap's UUID and event counter to the mddev's
 595          */
 596         if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
 597                 printk(KERN_INFO "%s: bitmap superblock UUID mismatch\n",
 598                         bmname(bitmap));
 599                 goto out;
 600         }
 601         events = le64_to_cpu(sb->events);
 602         if (events < bitmap->mddev->events) {
 603                 printk(KERN_INFO "%s: bitmap file is out of date (%llu < %llu) "
 604                         "-- forcing full recovery\n", bmname(bitmap), events,
 605                         (unsigned long long) bitmap->mddev->events);
 606                 sb->state |= cpu_to_le32(BITMAP_STALE);
 607         }
 608 success:
 609         /* assign fields using values from superblock */
 610         bitmap->mddev->bitmap_info.chunksize = chunksize;
 611         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 612         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 613         bitmap->flags |= le32_to_cpu(sb->state);
 614         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
 615                 bitmap->flags |= BITMAP_HOSTENDIAN;
 616         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
 617         if (sb->state & cpu_to_le32(BITMAP_STALE))
 618                 bitmap->events_cleared = bitmap->mddev->events;
 619         err = 0;
 620 out:
 621         kunmap_atomic(sb, KM_USER0);
 622         if (err)
 623                 bitmap_print_sb(bitmap);
 624         return err;
 625 }
 626
 627 enum bitmap_mask_op {
 628         MASK_SET,
 629         MASK_UNSET
 630 };
 631
 632 /* record the state of the bitmap in the superblock.  Return the old value */
 633 static int bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
 634                              enum bitmap_mask_op op)
 635 {
 636         bitmap_super_t *sb;
 637         unsigned long flags;
 638         int old;
 639
 640         spin_lock_irqsave(&bitmap->lock, flags);
 641         if (!bitmap->sb_page) { /* can't set the state */
 642                 spin_unlock_irqrestore(&bitmap->lock, flags);
 643                 return 0;
 644         }
 645         spin_unlock_irqrestore(&bitmap->lock, flags);
 646         sb = kmap_atomic(bitmap->sb_page, KM_USER0);
 647         old = le32_to_cpu(sb->state) & bits;
 648         switch (op) {
 649         case MASK_SET:
 650                 sb->state |= cpu_to_le32(bits);
 651                 break;
 652         case MASK_UNSET:
 653                 sb->state &= cpu_to_le32(~bits);
 654                 break;
 655         default:
 656                 BUG();
 657         }
 658         kunmap_atomic(sb, KM_USER0);
 659         return old;
 660 }
 661
 662 /*
 663  * general bitmap file operations
 664  */
 665
 666 /*
 667  * on-disk bitmap:
 668  *
 669  * Use one bit per "chunk" (block set). We do the disk I/O on the bitmap
 670  * file a page at a time. There's a superblock at the start of the file.
 671  */
 672 /* calculate the index of the page that contains this bit */
 673 static inline unsigned long file_page_index(struct bitmap *bitmap, unsigned long chunk)
 674 {
 675         if (!bitmap->mddev->bitmap_info.external)
 676                 chunk += sizeof(bitmap_super_t) << 3;
 677         return chunk >> PAGE_BIT_SHIFT;
 678 }
 679
 680 /* calculate the (bit) offset of this bit within a page */
 681 static inline unsigned long file_page_offset(struct bitmap *bitmap, unsigned long chunk)
 682 {
 683         if (!bitmap->mddev->bitmap_info.external)
 684                 chunk += sizeof(bitmap_super_t) << 3;
 685         return chunk & (PAGE_BITS - 1);
 686 }
 687
 688 /*
 689  * return a pointer to the page in the filemap that contains the given bit
 690  *
 691  * this lookup is complicated by the fact that the bitmap sb might be exactly
 692  * 1 page (e.g., x86) or less than 1 page -- so the bitmap might start on page
 693  * 0 or page 1
 694  */
 695 static inline struct page *filemap_get_page(struct bitmap *bitmap,
 696                                         unsigned long chunk)
 697 {
 698         if (bitmap->filemap == NULL)
 699                 return NULL;
 700         if (file_page_index(bitmap, chunk) >= bitmap->file_pages)
 701                 return NULL;
 702         return bitmap->filemap[file_page_index(bitmap, chunk)
 703                                - file_page_index(bitmap, 0)];
 704 }
 705
 706 static void bitmap_file_unmap(struct bitmap *bitmap)
 707 {
 708         struct page **map, *sb_page;
 709         unsigned long *attr;
 710         int pages;
 711         unsigned long flags;
 712
 713         spin_lock_irqsave(&bitmap->lock, flags);
 714         map = bitmap->filemap;
 715         bitmap->filemap = NULL;
 716         attr = bitmap->filemap_attr;
 717         bitmap->filemap_attr = NULL;
 718         pages = bitmap->file_pages;
 719         bitmap->file_pages = 0;
 720         sb_page = bitmap->sb_page;
 721         bitmap->sb_page = NULL;
 722         spin_unlock_irqrestore(&bitmap->lock, flags);
 723
 724         while (pages--)
 725                 if (map[pages] != sb_page) /* 0 is sb_page, release it below */
 726                         free_buffers(map[pages]);
 727         kfree(map);
 728         kfree(attr);
 729
 730         if (sb_page)
 731                 free_buffers(sb_page);
 732 }
 733
 734 static void bitmap_file_put(struct bitmap *bitmap)
 735 {
 736         struct file *file;
 737         unsigned long flags;
 738
 739         spin_lock_irqsave(&bitmap->lock, flags);
 740         file = bitmap->file;
 741         bitmap->file = NULL;
 742         spin_unlock_irqrestore(&bitmap->lock, flags);
 743
 744         if (file)
 745                 wait_event(bitmap->write_wait,
 746                            atomic_read(&bitmap->pending_writes)==0);
 747         bitmap_file_unmap(bitmap);
 748
 749         if (file) {
 750                 struct inode *inode = file->f_path.dentry->d_inode;
 751                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
 752                 fput(file);
 753         }
 754 }
 755
 756 /*
 757  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
 758  * then it is no longer reliable, so we stop using it and we mark the file
 759  * as failed in the superblock
 760  */
 761 static void bitmap_file_kick(struct bitmap *bitmap)
 762 {
 763         char *path, *ptr = NULL;
 764
 765         if (bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET) == 0) {
 766                 bitmap_update_sb(bitmap);
 767
 768                 if (bitmap->file) {
 769                         path = kmalloc(PAGE_SIZE, GFP_KERNEL);
 770                         if (path)
 771                                 ptr = d_path(&bitmap->file->f_path, path,
 772                                              PAGE_SIZE);
 773
 774                         printk(KERN_ALERT
 775                               "%s: kicking failed bitmap file %s from array!\n",
 776                               bmname(bitmap), IS_ERR(ptr) ? "" : ptr);
 777
 778                         kfree(path);
 779                 } else
 780                         printk(KERN_ALERT
 781                                "%s: disabling internal bitmap due to errors\n",
 782                                bmname(bitmap));
 783         }
 784
 785         bitmap_file_put(bitmap);
 786
 787         return;
 788 }
 789
 790 enum bitmap_page_attr {
 791         BITMAP_PAGE_DIRTY = 0,     /* there are set bits that need to be synced */
 792         BITMAP_PAGE_CLEAN = 1,     /* there are bits that might need to be cleared */
 793         BITMAP_PAGE_NEEDWRITE = 2, /* there are cleared bits that need to be synced */
 794 };
 795
 796 static inline void set_page_attr(struct bitmap *bitmap, struct page *page,
 797                                 enum bitmap_page_attr attr)
 798 {
 799         if (page)
 800                 __set_bit((page->index<<2) + attr, bitmap->filemap_attr);
 801         else
 802                 __set_bit(attr, &bitmap->logattrs);
 803 }
 804
 805 static inline void clear_page_attr(struct bitmap *bitmap, struct page *page,
 806                                 enum bitmap_page_attr attr)
 807 {
 808         if (page)
 809                 __clear_bit((page->index<<2) + attr, bitmap->filemap_attr);
 810         else
 811                 __clear_bit(attr, &bitmap->logattrs);
 812 }
 813
 814 static inline unsigned long test_page_attr(struct bitmap *bitmap, struct page *page,
 815                                            enum bitmap_page_attr attr)
 816 {
 817         if (page)
 818                 return test_bit((page->index<<2) + attr, bitmap->filemap_attr);
 819         else
 820                 return test_bit(attr, &bitmap->logattrs);
 821 }
 822
 823 /*
 824  * bitmap_file_set_bit -- called before performing a write to the md device
 825  * to set (and eventually sync) a particular bit in the bitmap file
 826  *
 827  * we set the bit immediately, then we record the page number so that
 828  * when an unplug occurs, we can flush the dirty pages out to disk
 829  */
 830 static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 831 {
 832         unsigned long bit;
 833         struct page *page = NULL;
 834         void *kaddr;
 835         unsigned long chunk = block >> CHUNK_BLOCK_SHIFT(bitmap);
 836
 837         if (!bitmap->filemap) {
 838                 struct dm_dirty_log *log = bitmap->mddev->bitmap_info.log;
 839                 if (log)
 840                         log->type->mark_region(log, chunk);
 841         } else {
 842
 843                 page = filemap_get_page(bitmap, chunk);
 844                 if (!page)
 845                         return;
 846                 bit = file_page_offset(bitmap, chunk);
 847
 848                 /* set the bit */
 849                 kaddr = kmap_atomic(page, KM_USER0);
 850                 if (bitmap->flags & BITMAP_HOSTENDIAN)
 851                         set_bit(bit, kaddr);
 852                 else
 853                         ext2_set_bit(bit, kaddr);
 854                 kunmap_atomic(kaddr, KM_USER0);
 855                 PRINTK("set file bit %lu page %lu\n", bit, page->index);
 856         }
 857         /* record page number so it gets flushed to disk when unplug occurs */
 858         set_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 859 }
 860
 861 /* this gets called when the md device is ready to unplug its underlying
 862  * (slave) device queues -- before we let any writes go down, we need to
 863  * sync the dirty pages of the bitmap file to disk */
 864 void bitmap_unplug(struct bitmap *bitmap)
 865 {
 866         unsigned long i, flags;
 867         int dirty, need_write;
 868         struct page *page;
 869         int wait = 0;
 870
 871         if (!bitmap)
 872                 return;
 873         if (!bitmap->filemap) {
 874                 /* Must be using a dirty_log */
 875                 struct dm_dirty_log *log = bitmap->mddev->bitmap_info.log;
 876                 dirty = test_and_clear_bit(BITMAP_PAGE_DIRTY, &bitmap->logattrs);
 877                 need_write = test_and_clear_bit(BITMAP_PAGE_NEEDWRITE, &bitmap->logattrs);
 878                 if (dirty || need_write)
 879                         if (log->type->flush(log))
 880                                 bitmap->flags |= BITMAP_WRITE_ERROR;
 881                 goto out;
 882         }
 883
 884         /* look at each page to see if there are any set bits that need to be
 885          * flushed out to disk */
 886         for (i = 0; i < bitmap->file_pages; i++) {
 887                 spin_lock_irqsave(&bitmap->lock, flags);
 888                 if (!bitmap->filemap) {
 889                         spin_unlock_irqrestore(&bitmap->lock, flags);
 890                         return;
 891                 }
 892                 page = bitmap->filemap[i];
 893                 dirty = test_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 894                 need_write = test_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 895                 clear_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 896                 clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 897                 if (dirty)
 898                         wait = 1;
 899                 spin_unlock_irqrestore(&bitmap->lock, flags);
 900
 901                 if (dirty || need_write)
 902                         write_page(bitmap, page, 0);
 903         }
 904         if (wait) { /* if any writes were performed, we need to wait on them */
 905                 if (bitmap->file)
 906                         wait_event(bitmap->write_wait,
 907                                    atomic_read(&bitmap->pending_writes)==0);
 908                 else
 909                         md_super_wait(bitmap->mddev);
 910         }
 911 out:
 912         if (bitmap->flags & BITMAP_WRITE_ERROR)
 913                 bitmap_file_kick(bitmap);
 914 }
 915 EXPORT_SYMBOL(bitmap_unplug);
 916
 917 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
 918 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
 919  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
 920  * memory mapping of the bitmap file
 921  * Special cases:
 922  *   if there's no bitmap file, or if the bitmap file had been
 923  *   previously kicked from the array, we mark all the bits as
 924  *   1's in order to cause a full resync.
 925  *
 926  * We ignore all bits for sectors that end earlier than 'start'.
 927  * This is used when reading an out-of-date bitmap...
 928  */
 929 static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
 930 {
 931         unsigned long i, chunks, index, oldindex, bit;
 932         struct page *page = NULL, *oldpage = NULL;
 933         unsigned long num_pages, bit_cnt = 0;
 934         struct file *file;
 935         unsigned long bytes, offset;
 936         int outofdate;
 937         int ret = -ENOSPC;
 938         void *paddr;
 939
 940         chunks = bitmap->chunks;
 941         file = bitmap->file;
 942
 943         BUG_ON(!file && !bitmap->mddev->bitmap_info.offset);
 944
 945 #ifdef INJECT_FAULTS_3
 946         outofdate = 1;
 947 #else
 948         outofdate = bitmap->flags & BITMAP_STALE;
 949 #endif
 950         if (outofdate)
 951                 printk(KERN_INFO "%s: bitmap file is out of date, doing full "
 952                         "recovery\n", bmname(bitmap));
 953
 954         bytes = DIV_ROUND_UP(bitmap->chunks, 8);
 955         if (!bitmap->mddev->bitmap_info.external)
 956                 bytes += sizeof(bitmap_super_t);
 957
 958         num_pages = DIV_ROUND_UP(bytes, PAGE_SIZE);
 959
 960         if (file && i_size_read(file->f_mapping->host) < bytes) {
 961                 printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
 962                         bmname(bitmap),
 963                         (unsigned long) i_size_read(file->f_mapping->host),
 964                         bytes);
 965                 goto err;
 966         }
 967
 968         ret = -ENOMEM;
 969
 970         bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
 971         if (!bitmap->filemap)
 972                 goto err;
 973
 974         /* We need 4 bits per page, rounded up to a multiple of sizeof(unsigned long) */
 975         bitmap->filemap_attr = kzalloc(
 976                 roundup(DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
 977                 GFP_KERNEL);
 978         if (!bitmap->filemap_attr)
 979                 goto err;
 980
 981         oldindex = ~0L;
 982
 983         for (i = 0; i < chunks; i++) {
 984                 int b;
 985                 index = file_page_index(bitmap, i);
 986                 bit = file_page_offset(bitmap, i);
 987                 if (index != oldindex) { /* this is a new page, read it in */
 988                         int count;
 989                         /* unmap the old page, we're done with it */
 990                         if (index == num_pages-1)
 991                                 count = bytes - index * PAGE_SIZE;
 992                         else
 993                                 count = PAGE_SIZE;
 994                         if (index == 0 && bitmap->sb_page) {
 995                                 /*
 996                                  * if we're here then the superblock page
 997                                  * contains some bits (PAGE_SIZE != sizeof sb)
 998                                  * we've already read it in, so just use it
 999                                  */
1000                                 page = bitmap->sb_page;
1001                                 offset = sizeof(bitmap_super_t);
1002                                 if (!file)
1003                                         read_sb_page(bitmap->mddev,
1004                                                      bitmap->mddev->bitmap_info.offset,
1005                                                      page,
1006                                                      index, count);
1007                         } else if (file) {
1008                                 page = read_page(file, index, bitmap, count);
1009                                 offset = 0;
1010                         } else {
1011                                 page = read_sb_page(bitmap->mddev,
1012                                                     bitmap->mddev->bitmap_info.offset,
1013                                                     NULL,
1014                                                     index, count);
1015                                 offset = 0;
1016                         }
1017                         if (IS_ERR(page)) { /* read error */
1018                                 ret = PTR_ERR(page);
1019                                 goto err;
1020                         }
1021
1022                         oldindex = index;
1023                         oldpage = page;
1024
1025                         bitmap->filemap[bitmap->file_pages++] = page;
1026                         bitmap->last_page_size = count;
1027
1028                         if (outofdate) {
1029                                 /*
1030                                  * if bitmap is out of date, dirty the
1031                                  * whole page and write it out
1032                                  */
1033                                 paddr = kmap_atomic(page, KM_USER0);
1034                                 memset(paddr + offset, 0xff,
1035                                        PAGE_SIZE - offset);
1036                                 kunmap_atomic(paddr, KM_USER0);
1037                                 write_page(bitmap, page, 1);
1038
1039                                 ret = -EIO;
1040                                 if (bitmap->flags & BITMAP_WRITE_ERROR)
1041                                         goto err;
1042                         }
1043                 }
1044                 paddr = kmap_atomic(page, KM_USER0);
1045                 if (bitmap->flags & BITMAP_HOSTENDIAN)
1046                         b = test_bit(bit, paddr);
1047                 else
1048                         b = ext2_test_bit(bit, paddr);
1049                 kunmap_atomic(paddr, KM_USER0);
1050                 if (b) {
1051                         /* if the disk bit is set, set the memory bit */
1052                         int needed = ((sector_t)(i+1) << (CHUNK_BLOCK_SHIFT(bitmap))
1053                                       >= start);
1054                         bitmap_set_memory_bits(bitmap,
1055                                                (sector_t)i << CHUNK_BLOCK_SHIFT(bitmap),
1056                                                needed);
1057                         bit_cnt++;
1058                         set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1059                 }
1060         }
1061
1062         /* everything went OK */
1063         ret = 0;
1064         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_UNSET);
1065
1066         if (bit_cnt) { /* Kick recovery if any bits were set */
1067                 set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
1068                 md_wakeup_thread(bitmap->mddev->thread);
1069         }
1070
1071         printk(KERN_INFO "%s: bitmap initialized from disk: "
1072                 "read %lu/%lu pages, set %lu bits\n",
1073                 bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt);
1074
1075         return 0;
1076
1077  err:
1078         printk(KERN_INFO "%s: bitmap initialisation failed: %d\n",
1079                bmname(bitmap), ret);
1080         return ret;
1081 }
1082
1083 void bitmap_write_all(struct bitmap *bitmap)
1084 {
1085         /* We don't actually write all bitmap blocks here,
1086          * just flag them as needing to be written
1087          */
1088         int i;
1089
1090         for (i = 0; i < bitmap->file_pages; i++)
1091                 set_page_attr(bitmap, bitmap->filemap[i],
1092                               BITMAP_PAGE_NEEDWRITE);
1093 }
1094
1095 static void bitmap_count_page(struct bitmap *bitmap, sector_t offset, int inc)
1096 {
1097         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1098         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1099         bitmap->bp[page].count += inc;
1100         bitmap_checkfree(bitmap, page);
1101 }
1102 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1103                                             sector_t offset, int *blocks,
1104                                             int create);
1105
1106 /*
1107  * bitmap daemon -- periodically wakes up to clean bits and flush pages
1108  *                      out to disk
1109  */
1110
1111 void bitmap_daemon_work(mddev_t *mddev)
1112 {
1113         struct bitmap *bitmap;
1114         unsigned long j;
1115         unsigned long flags;
1116         struct page *page = NULL, *lastpage = NULL;
1117         int blocks;
1118         void *paddr;
1119         struct dm_dirty_log *log = mddev->bitmap_info.log;
1120
1121         /* Use a mutex to guard daemon_work against
1122          * bitmap_destroy.
1123          */
1124         mutex_lock(&mddev->bitmap_info.mutex);
1125         bitmap = mddev->bitmap;
1126         if (bitmap == NULL) {
1127                 mutex_unlock(&mddev->bitmap_info.mutex);
1128                 return;
1129         }
1130         if (time_before(jiffies, bitmap->daemon_lastrun
1131                         + bitmap->mddev->bitmap_info.daemon_sleep))
1132                 goto done;
1133
1134         bitmap->daemon_lastrun = jiffies;
1135         if (bitmap->allclean) {
1136                 bitmap->mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1137                 goto done;
1138         }
1139         bitmap->allclean = 1;
1140
1141         spin_lock_irqsave(&bitmap->lock, flags);
1142         for (j = 0; j < bitmap->chunks; j++) {
1143                 bitmap_counter_t *bmc;
1144                 if (!bitmap->filemap) {
1145                         if (!log)
1146                                 /* error or shutdown */
1147                                 break;
1148                 } else
1149                         page = filemap_get_page(bitmap, j);
1150
1151                 if (page != lastpage) {
1152                         /* skip this page unless it's marked as needing cleaning */
1153                         if (!test_page_attr(bitmap, page, BITMAP_PAGE_CLEAN)) {
1154                                 int need_write = test_page_attr(bitmap, page,
1155                                                                 BITMAP_PAGE_NEEDWRITE);
1156                                 if (need_write)
1157                                         clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
1158
1159                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1160                                 if (need_write) {
1161                                         write_page(bitmap, page, 0);
1162                                         bitmap->allclean = 0;
1163                                 }
1164                                 spin_lock_irqsave(&bitmap->lock, flags);
1165                                 j |= (PAGE_BITS - 1);
1166                                 continue;
1167                         }
1168
1169                         /* grab the new page, sync and release the old */
1170                         if (lastpage != NULL) {
1171                                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1172                                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1173                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1174                                         write_page(bitmap, lastpage, 0);
1175                                 } else {
1176                                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1177                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1178                                 }
1179                         } else
1180                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1181                         lastpage = page;
1182
1183                         /* We are possibly going to clear some bits, so make
1184                          * sure that events_cleared is up-to-date.
1185                          */
1186                         if (bitmap->need_sync &&
1187                             bitmap->mddev->bitmap_info.external == 0) {
1188                                 bitmap_super_t *sb;
1189                                 bitmap->need_sync = 0;
1190                                 sb = kmap_atomic(bitmap->sb_page, KM_USER0);
1191                                 sb->events_cleared =
1192                                         cpu_to_le64(bitmap->events_cleared);
1193                                 kunmap_atomic(sb, KM_USER0);
1194                                 write_page(bitmap, bitmap->sb_page, 1);
1195                         }
1196                         spin_lock_irqsave(&bitmap->lock, flags);
1197                         if (!bitmap->need_sync)
1198                                 clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1199                 }
1200                 bmc = bitmap_get_counter(bitmap,
1201                                          (sector_t)j << CHUNK_BLOCK_SHIFT(bitmap),
1202                                          &blocks, 0);
1203                 if (bmc) {
1204                         if (*bmc)
1205                                 bitmap->allclean = 0;
1206
1207                         if (*bmc == 2) {
1208                                 *bmc = 1; /* maybe clear the bit next time */
1209                                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1210                         } else if (*bmc == 1 && !bitmap->need_sync) {
1211                                 /* we can clear the bit */
1212                                 *bmc = 0;
1213                                 bitmap_count_page(bitmap,
1214                                                   (sector_t)j << CHUNK_BLOCK_SHIFT(bitmap),
1215                                                   -1);
1216
1217                                 /* clear the bit */
1218                                 if (page) {
1219                                         paddr = kmap_atomic(page, KM_USER0);
1220                                         if (bitmap->flags & BITMAP_HOSTENDIAN)
1221                                                 clear_bit(file_page_offset(bitmap, j),
1222                                                           paddr);
1223                                         else
1224                                                 ext2_clear_bit(file_page_offset(bitmap, j),
1225                                                                paddr);
1226                                         kunmap_atomic(paddr, KM_USER0);
1227                                 } else
1228                                         log->type->clear_region(log, j);
1229                         }
1230                 } else
1231                         j |= PAGE_COUNTER_MASK;
1232         }
1233         spin_unlock_irqrestore(&bitmap->lock, flags);
1234
1235         /* now sync the final page */
1236         if (lastpage != NULL || log != NULL) {
1237                 spin_lock_irqsave(&bitmap->lock, flags);
1238                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1239                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1240                         spin_unlock_irqrestore(&bitmap->lock, flags);
1241                         if (lastpage)
1242                                 write_page(bitmap, lastpage, 0);
1243                         else
1244                                 if (log->type->flush(log))
1245                                         bitmap->flags |= BITMAP_WRITE_ERROR;
1246                 } else {
1247                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1248                         spin_unlock_irqrestore(&bitmap->lock, flags);
1249                 }
1250         }
1251
1252  done:
1253         if (bitmap->allclean == 0)
1254                 bitmap->mddev->thread->timeout =
1255                         bitmap->mddev->bitmap_info.daemon_sleep;
1256         mutex_unlock(&mddev->bitmap_info.mutex);
1257 }
1258
1259 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1260                                             sector_t offset, int *blocks,
1261                                             int create)
1262 __releases(bitmap->lock)
1263 __acquires(bitmap->lock)
1264 {
1265         /* If 'create', we might release the lock and reclaim it.
1266          * The lock must have been taken with interrupts enabled.
1267          * If !create, we don't release the lock.
1268          */
1269         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1270         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1271         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1272         sector_t csize;
1273         int err;
1274
1275         err = bitmap_checkpage(bitmap, page, create);
1276
1277         if (bitmap->bp[page].hijacked ||
1278             bitmap->bp[page].map == NULL)
1279                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap) +
1280                                           PAGE_COUNTER_SHIFT - 1);
1281         else
1282                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1283         *blocks = csize - (offset & (csize - 1));
1284
1285         if (err < 0)
1286                 return NULL;
1287
1288         /* now locked ... */
1289
1290         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1291                 /* should we use the first or second counter field
1292                  * of the hijacked pointer? */
1293                 int hi = (pageoff > PAGE_COUNTER_MASK);
1294                 return  &((bitmap_counter_t *)
1295                           &bitmap->bp[page].map)[hi];
1296         } else /* page is allocated */
1297                 return (bitmap_counter_t *)
1298                         &(bitmap->bp[page].map[pageoff]);
1299 }
1300
1301 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1302 {
1303         if (!bitmap)
1304                 return 0;
1305
1306         if (behind) {
1307                 int bw;
1308                 atomic_inc(&bitmap->behind_writes);
1309                 bw = atomic_read(&bitmap->behind_writes);
1310                 if (bw > bitmap->behind_writes_used)
1311                         bitmap->behind_writes_used = bw;
1312
1313                 PRINTK(KERN_DEBUG "inc write-behind count %d/%d\n",
1314                        bw, bitmap->max_write_behind);
1315         }
1316
1317         while (sectors) {
1318                 int blocks;
1319                 bitmap_counter_t *bmc;
1320
1321                 spin_lock_irq(&bitmap->lock);
1322                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 1);
1323                 if (!bmc) {
1324                         spin_unlock_irq(&bitmap->lock);
1325                         return 0;
1326                 }
1327
1328                 if (unlikely((*bmc & COUNTER_MAX) == COUNTER_MAX)) {
1329                         DEFINE_WAIT(__wait);
1330                         /* note that it is safe to do the prepare_to_wait
1331                          * after the test as long as we do it before dropping
1332                          * the spinlock.
1333                          */
1334                         prepare_to_wait(&bitmap->overflow_wait, &__wait,
1335                                         TASK_UNINTERRUPTIBLE);
1336                         spin_unlock_irq(&bitmap->lock);
1337                         md_unplug(bitmap->mddev);
1338                         schedule();
1339                         finish_wait(&bitmap->overflow_wait, &__wait);
1340                         continue;
1341                 }
1342
1343                 switch (*bmc) {
1344                 case 0:
1345                         bitmap_file_set_bit(bitmap, offset);
1346                         bitmap_count_page(bitmap, offset, 1);
1347                         /* fall through */
1348                 case 1:
1349                         *bmc = 2;
1350                 }
1351
1352                 (*bmc)++;
1353
1354                 spin_unlock_irq(&bitmap->lock);
1355
1356                 offset += blocks;
1357                 if (sectors > blocks)
1358                         sectors -= blocks;
1359                 else
1360                         sectors = 0;
1361         }
1362         bitmap->allclean = 0;
1363         return 0;
1364 }
1365 EXPORT_SYMBOL(bitmap_startwrite);
1366
1367 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1368                      int success, int behind)
1369 {
1370         if (!bitmap)
1371                 return;
1372         if (behind) {
1373                 if (atomic_dec_and_test(&bitmap->behind_writes))
1374                         wake_up(&bitmap->behind_wait);
1375                 PRINTK(KERN_DEBUG "dec write-behind count %d/%d\n",
1376                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1377         }
1378         if (bitmap->mddev->degraded)
1379                 /* Never clear bits or update events_cleared when degraded */
1380                 success = 0;
1381
1382         while (sectors) {
1383                 int blocks;
1384                 unsigned long flags;
1385                 bitmap_counter_t *bmc;
1386
1387                 spin_lock_irqsave(&bitmap->lock, flags);
1388                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 0);
1389                 if (!bmc) {
1390                         spin_unlock_irqrestore(&bitmap->lock, flags);
1391                         return;
1392                 }
1393
1394                 if (success &&
1395                     bitmap->events_cleared < bitmap->mddev->events) {
1396                         bitmap->events_cleared = bitmap->mddev->events;
1397                         bitmap->need_sync = 1;
1398                         sysfs_notify_dirent_safe(bitmap->sysfs_can_clear);
1399                 }
1400
1401                 if (!success && ! (*bmc & NEEDED_MASK))
1402                         *bmc |= NEEDED_MASK;
1403
1404                 if ((*bmc & COUNTER_MAX) == COUNTER_MAX)
1405                         wake_up(&bitmap->overflow_wait);
1406
1407                 (*bmc)--;
1408                 if (*bmc <= 2)
1409                         set_page_attr(bitmap,
1410                                       filemap_get_page(
1411                                               bitmap,
1412                                               offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1413                                       BITMAP_PAGE_CLEAN);
1414
1415                 spin_unlock_irqrestore(&bitmap->lock, flags);
1416                 offset += blocks;
1417                 if (sectors > blocks)
1418                         sectors -= blocks;
1419                 else
1420                         sectors = 0;
1421         }
1422 }
1423 EXPORT_SYMBOL(bitmap_endwrite);
1424
1425 static int __bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
1426                                int degraded)
1427 {
1428         bitmap_counter_t *bmc;
1429         int rv;
1430         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1431                 *blocks = 1024;
1432                 return 1; /* always resync if no bitmap */
1433         }
1434         spin_lock_irq(&bitmap->lock);
1435         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1436         rv = 0;
1437         if (bmc) {
1438                 /* locked */
1439                 if (RESYNC(*bmc))
1440                         rv = 1;
1441                 else if (NEEDED(*bmc)) {
1442                         rv = 1;
1443                         if (!degraded) { /* don't set/clear bits if degraded */
1444                                 *bmc |= RESYNC_MASK;
1445                                 *bmc &= ~NEEDED_MASK;
1446                         }
1447                 }
1448         }
1449         spin_unlock_irq(&bitmap->lock);
1450         bitmap->allclean = 0;
1451         return rv;
1452 }
1453
1454 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
1455                       int degraded)
1456 {
1457         /* bitmap_start_sync must always report on multiples of whole
1458          * pages, otherwise resync (which is very PAGE_SIZE based) will
1459          * get confused.
1460          * So call __bitmap_start_sync repeatedly (if needed) until
1461          * At least PAGE_SIZE>>9 blocks are covered.
1462          * Return the 'or' of the result.
1463          */
1464         int rv = 0;
1465         int blocks1;
1466
1467         *blocks = 0;
1468         while (*blocks < (PAGE_SIZE>>9)) {
1469                 rv |= __bitmap_start_sync(bitmap, offset,
1470                                           &blocks1, degraded);
1471                 offset += blocks1;
1472                 *blocks += blocks1;
1473         }
1474         return rv;
1475 }
1476 EXPORT_SYMBOL(bitmap_start_sync);
1477
1478 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int aborted)
1479 {
1480         bitmap_counter_t *bmc;
1481         unsigned long flags;
1482
1483         if (bitmap == NULL) {
1484                 *blocks = 1024;
1485                 return;
1486         }
1487         spin_lock_irqsave(&bitmap->lock, flags);
1488         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1489         if (bmc == NULL)
1490                 goto unlock;
1491         /* locked */
1492         if (RESYNC(*bmc)) {
1493                 *bmc &= ~RESYNC_MASK;
1494
1495                 if (!NEEDED(*bmc) && aborted)
1496                         *bmc |= NEEDED_MASK;
1497                 else {
1498                         if (*bmc <= 2)
1499                                 set_page_attr(bitmap,
1500                                               filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1501                                               BITMAP_PAGE_CLEAN);
1502                 }
1503         }
1504  unlock:
1505         spin_unlock_irqrestore(&bitmap->lock, flags);
1506         bitmap->allclean = 0;
1507 }
1508 EXPORT_SYMBOL(bitmap_end_sync);
1509
1510 void bitmap_close_sync(struct bitmap *bitmap)
1511 {
1512         /* Sync has finished, and any bitmap chunks that weren't synced
1513          * properly have been aborted.  It remains to us to clear the
1514          * RESYNC bit wherever it is still on
1515          */
1516         sector_t sector = 0;
1517         int blocks;
1518         if (!bitmap)
1519                 return;
1520         while (sector < bitmap->mddev->resync_max_sectors) {
1521                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1522                 sector += blocks;
1523         }
1524 }
1525 EXPORT_SYMBOL(bitmap_close_sync);
1526
1527 void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector)
1528 {
1529         sector_t s = 0;
1530         int blocks;
1531
1532         if (!bitmap)
1533                 return;
1534         if (sector == 0) {
1535                 bitmap->last_end_sync = jiffies;
1536                 return;
1537         }
1538         if (time_before(jiffies, (bitmap->last_end_sync
1539                                   + bitmap->mddev->bitmap_info.daemon_sleep)))
1540                 return;
1541         wait_event(bitmap->mddev->recovery_wait,
1542                    atomic_read(&bitmap->mddev->recovery_active) == 0);
1543
1544         bitmap->mddev->curr_resync_completed = bitmap->mddev->curr_resync;
1545         set_bit(MD_CHANGE_CLEAN, &bitmap->mddev->flags);
1546         sector &= ~((1ULL << CHUNK_BLOCK_SHIFT(bitmap)) - 1);
1547         s = 0;
1548         while (s < sector && s < bitmap->mddev->resync_max_sectors) {
1549                 bitmap_end_sync(bitmap, s, &blocks, 0);
1550                 s += blocks;
1551         }
1552         bitmap->last_end_sync = jiffies;
1553         sysfs_notify(&bitmap->mddev->kobj, NULL, "sync_completed");
1554 }
1555 EXPORT_SYMBOL(bitmap_cond_end_sync);
1556
1557 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1558 {
1559         /* For each chunk covered by any of these sectors, set the
1560          * counter to 1 and set resync_needed.  They should all
1561          * be 0 at this point
1562          */
1563
1564         int secs;
1565         bitmap_counter_t *bmc;
1566         spin_lock_irq(&bitmap->lock);
1567         bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
1568         if (!bmc) {
1569                 spin_unlock_irq(&bitmap->lock);
1570                 return;
1571         }
1572         if (!*bmc) {
1573                 struct page *page;
1574                 *bmc = 1 | (needed ? NEEDED_MASK : 0);
1575                 bitmap_count_page(bitmap, offset, 1);
1576                 page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));
1577                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1578         }
1579         spin_unlock_irq(&bitmap->lock);
1580         bitmap->allclean = 0;
1581 }
1582
1583 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
1584 void bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1585 {
1586         unsigned long chunk;
1587
1588         for (chunk = s; chunk <= e; chunk++) {
1589                 sector_t sec = (sector_t)chunk << CHUNK_BLOCK_SHIFT(bitmap);
1590                 bitmap_set_memory_bits(bitmap, sec, 1);
1591                 bitmap_file_set_bit(bitmap, sec);
1592                 if (sec < bitmap->mddev->recovery_cp)
1593                         /* We are asserting that the array is dirty,
1594                          * so move the recovery_cp address back so
1595                          * that it is obvious that it is dirty
1596                          */
1597                         bitmap->mddev->recovery_cp = sec;
1598         }
1599 }
1600
1601 /*
1602  * flush out any pending updates
1603  */
1604 void bitmap_flush(mddev_t *mddev)
1605 {
1606         struct bitmap *bitmap = mddev->bitmap;
1607         long sleep;
1608
1609         if (!bitmap) /* there was no bitmap */
1610                 return;
1611
1612         /* run the daemon_work three time to ensure everything is flushed
1613          * that can be
1614          */
1615         sleep = mddev->bitmap_info.daemon_sleep * 2;
1616         bitmap->daemon_lastrun -= sleep;
1617         bitmap_daemon_work(mddev);
1618         bitmap->daemon_lastrun -= sleep;
1619         bitmap_daemon_work(mddev);
1620         bitmap->daemon_lastrun -= sleep;
1621         bitmap_daemon_work(mddev);
1622         bitmap_update_sb(bitmap);
1623 }
1624
1625 /*
1626  * free memory that was allocated
1627  */
1628 static void bitmap_free(struct bitmap *bitmap)
1629 {
1630         unsigned long k, pages;
1631         struct bitmap_page *bp;
1632
1633         if (!bitmap) /* there was no bitmap */
1634                 return;
1635
1636         /* release the bitmap file and kill the daemon */
1637         bitmap_file_put(bitmap);
1638
1639         bp = bitmap->bp;
1640         pages = bitmap->pages;
1641
1642         /* free all allocated memory */
1643
1644         if (bp) /* deallocate the page memory */
1645                 for (k = 0; k < pages; k++)
1646                         if (bp[k].map && !bp[k].hijacked)
1647                                 kfree(bp[k].map);
1648         kfree(bp);
1649         kfree(bitmap);
1650 }
1651
1652 void bitmap_destroy(mddev_t *mddev)
1653 {
1654         struct bitmap *bitmap = mddev->bitmap;
1655
1656         if (!bitmap) /* there was no bitmap */
1657                 return;
1658
1659         mutex_lock(&mddev->bitmap_info.mutex);
1660         mddev->bitmap = NULL; /* disconnect from the md device */
1661         mutex_unlock(&mddev->bitmap_info.mutex);
1662         if (mddev->thread)
1663                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1664
1665         if (bitmap->sysfs_can_clear)
1666                 sysfs_put(bitmap->sysfs_can_clear);
1667
1668         bitmap_free(bitmap);
1669 }
1670
1671 /*
1672  * initialize the bitmap structure
1673  * if this returns an error, bitmap_destroy must be called to do clean up
1674  */
1675 int bitmap_create(mddev_t *mddev)
1676 {
1677         struct bitmap *bitmap;
1678         sector_t blocks = mddev->resync_max_sectors;
1679         unsigned long chunks;
1680         unsigned long pages;
1681         struct file *file = mddev->bitmap_info.file;
1682         int err;
1683         struct sysfs_dirent *bm = NULL;
1684
1685         BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
1686
1687         if (!file
1688             && !mddev->bitmap_info.offset
1689             && !mddev->bitmap_info.log) /* bitmap disabled, nothing to do */
1690                 return 0;
1691
1692         BUG_ON(file && mddev->bitmap_info.offset);
1693         BUG_ON(mddev->bitmap_info.offset && mddev->bitmap_info.log);
1694
1695         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1696         if (!bitmap)
1697                 return -ENOMEM;
1698
1699         spin_lock_init(&bitmap->lock);
1700         atomic_set(&bitmap->pending_writes, 0);
1701         init_waitqueue_head(&bitmap->write_wait);
1702         init_waitqueue_head(&bitmap->overflow_wait);
1703         init_waitqueue_head(&bitmap->behind_wait);
1704
1705         bitmap->mddev = mddev;
1706
1707         if (mddev->kobj.sd)
1708                 bm = sysfs_get_dirent(mddev->kobj.sd, NULL, "bitmap");
1709         if (bm) {
1710                 bitmap->sysfs_can_clear = sysfs_get_dirent(bm, NULL, "can_clear");
1711                 sysfs_put(bm);
1712         } else
1713                 bitmap->sysfs_can_clear = NULL;
1714
1715         bitmap->file = file;
1716         if (file) {
1717                 get_file(file);
1718                 /* As future accesses to this file will use bmap,
1719                  * and bypass the page cache, we must sync the file
1720                  * first.
1721                  */
1722                 vfs_fsync(file, 1);
1723         }
1724         /* read superblock from bitmap file (this sets mddev->bitmap_info.chunksize) */
1725         if (!mddev->bitmap_info.external)
1726                 err = bitmap_read_sb(bitmap);
1727         else {
1728                 err = 0;
1729                 if (mddev->bitmap_info.chunksize == 0 ||
1730                     mddev->bitmap_info.daemon_sleep == 0)
1731                         /* chunksize and time_base need to be
1732                          * set first. */
1733                         err = -EINVAL;
1734         }
1735         if (err)
1736                 goto error;
1737
1738         bitmap->daemon_lastrun = jiffies;
1739         bitmap->chunkshift = ffz(~mddev->bitmap_info.chunksize);
1740
1741         /* now that chunksize and chunkshift are set, we can use these macros */
1742         chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) >>
1743                         CHUNK_BLOCK_SHIFT(bitmap);
1744         pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
1745
1746         BUG_ON(!pages);
1747
1748         bitmap->chunks = chunks;
1749         bitmap->pages = pages;
1750         bitmap->missing_pages = pages;
1751         bitmap->counter_bits = COUNTER_BITS;
1752
1753         bitmap->syncchunk = ~0UL;
1754
1755 #ifdef INJECT_FATAL_FAULT_1
1756         bitmap->bp = NULL;
1757 #else
1758         bitmap->bp = kzalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
1759 #endif
1760         err = -ENOMEM;
1761         if (!bitmap->bp)
1762                 goto error;
1763
1764         printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
1765                 pages, bmname(bitmap));
1766
1767         mddev->bitmap = bitmap;
1768
1769
1770         return (bitmap->flags & BITMAP_WRITE_ERROR) ? -EIO : 0;
1771
1772  error:
1773         bitmap_free(bitmap);
1774         return err;
1775 }
1776
1777 int bitmap_load(mddev_t *mddev)
1778 {
1779         int err = 0;
1780         sector_t sector = 0;
1781         struct bitmap *bitmap = mddev->bitmap;
1782
1783         if (!bitmap)
1784                 goto out;
1785
1786         /* Clear out old bitmap info first:  Either there is none, or we
1787          * are resuming after someone else has possibly changed things,
1788          * so we should forget old cached info.
1789          * All chunks should be clean, but some might need_sync.
1790          */
1791         while (sector < mddev->resync_max_sectors) {
1792                 int blocks;
1793                 bitmap_start_sync(bitmap, sector, &blocks, 0);
1794                 sector += blocks;
1795         }
1796         bitmap_close_sync(bitmap);
1797
1798         if (mddev->bitmap_info.log) {
1799                 unsigned long i;
1800                 struct dm_dirty_log *log = mddev->bitmap_info.log;
1801                 for (i = 0; i < bitmap->chunks; i++)
1802                         if (!log->type->in_sync(log, i, 1))
1803                                 bitmap_set_memory_bits(bitmap,
1804                                                        (sector_t)i << CHUNK_BLOCK_SHIFT(bitmap),
1805                                                        1);
1806         } else {
1807                 sector_t start = 0;
1808                 if (mddev->degraded == 0
1809                     || bitmap->events_cleared == mddev->events)
1810                         /* no need to keep dirty bits to optimise a
1811                          * re-add of a missing device */
1812                         start = mddev->recovery_cp;
1813
1814                 err = bitmap_init_from_disk(bitmap, start);
1815         }
1816         if (err)
1817                 goto out;
1818
1819         mddev->thread->timeout = mddev->bitmap_info.daemon_sleep;
1820         md_wakeup_thread(mddev->thread);
1821
1822         bitmap_update_sb(bitmap);
1823
1824         if (bitmap->flags & BITMAP_WRITE_ERROR)
1825                 err = -EIO;
1826 out:
1827         return err;
1828 }
1829 EXPORT_SYMBOL_GPL(bitmap_load);
1830
1831 static ssize_t
1832 location_show(mddev_t *mddev, char *page)
1833 {
1834         ssize_t len;
1835         if (mddev->bitmap_info.file)
1836                 len = sprintf(page, "file");
1837         else if (mddev->bitmap_info.offset)
1838                 len = sprintf(page, "%+lld", (long long)mddev->bitmap_info.offset);
1839         else
1840                 len = sprintf(page, "none");
1841         len += sprintf(page+len, "\n");
1842         return len;
1843 }
1844
1845 static ssize_t
1846 location_store(mddev_t *mddev, const char *buf, size_t len)
1847 {
1848
1849         if (mddev->pers) {
1850                 if (!mddev->pers->quiesce)
1851                         return -EBUSY;
1852                 if (mddev->recovery || mddev->sync_thread)
1853                         return -EBUSY;
1854         }
1855
1856         if (mddev->bitmap || mddev->bitmap_info.file ||
1857             mddev->bitmap_info.offset) {
1858                 /* bitmap already configured.  Only option is to clear it */
1859                 if (strncmp(buf, "none", 4) != 0)
1860                         return -EBUSY;
1861                 if (mddev->pers) {
1862                         mddev->pers->quiesce(mddev, 1);
1863                         bitmap_destroy(mddev);
1864                         mddev->pers->quiesce(mddev, 0);
1865                 }
1866                 mddev->bitmap_info.offset = 0;
1867                 if (mddev->bitmap_info.file) {
1868                         struct file *f = mddev->bitmap_info.file;
1869                         mddev->bitmap_info.file = NULL;
1870                         restore_bitmap_write_access(f);
1871                         fput(f);
1872                 }
1873         } else {
1874                 /* No bitmap, OK to set a location */
1875                 long long offset;
1876                 if (strncmp(buf, "none", 4) == 0)
1877                         /* nothing to be done */;
1878                 else if (strncmp(buf, "file:", 5) == 0) {
1879                         /* Not supported yet */
1880                         return -EINVAL;
1881                 } else {
1882                         int rv;
1883                         if (buf[0] == '+')
1884                                 rv = strict_strtoll(buf+1, 10, &offset);
1885                         else
1886                                 rv = strict_strtoll(buf, 10, &offset);
1887                         if (rv)
1888                                 return rv;
1889                         if (offset == 0)
1890                                 return -EINVAL;
1891                         if (mddev->bitmap_info.external == 0 &&
1892                             mddev->major_version == 0 &&
1893                             offset != mddev->bitmap_info.default_offset)
1894                                 return -EINVAL;
1895                         mddev->bitmap_info.offset = offset;
1896                         if (mddev->pers) {
1897                                 mddev->pers->quiesce(mddev, 1);
1898                                 rv = bitmap_create(mddev);
1899                                 if (rv) {
1900                                         bitmap_destroy(mddev);
1901                                         mddev->bitmap_info.offset = 0;
1902                                 }
1903                                 mddev->pers->quiesce(mddev, 0);
1904                                 if (rv)
1905                                         return rv;
1906                         }
1907                 }
1908         }
1909         if (!mddev->external) {
1910                 /* Ensure new bitmap info is stored in
1911                  * metadata promptly.
1912                  */
1913                 set_bit(MD_CHANGE_DEVS, &mddev->flags);
1914                 md_wakeup_thread(mddev->thread);
1915         }
1916         return len;
1917 }
1918
1919 static struct md_sysfs_entry bitmap_location =
1920 __ATTR(location, S_IRUGO|S_IWUSR, location_show, location_store);
1921
1922 static ssize_t
1923 timeout_show(mddev_t *mddev, char *page)
1924 {
1925         ssize_t len;
1926         unsigned long secs = mddev->bitmap_info.daemon_sleep / HZ;
1927         unsigned long jifs = mddev->bitmap_info.daemon_sleep % HZ;
1928
1929         len = sprintf(page, "%lu", secs);
1930         if (jifs)
1931                 len += sprintf(page+len, ".%03u", jiffies_to_msecs(jifs));
1932         len += sprintf(page+len, "\n");
1933         return len;
1934 }
1935
1936 static ssize_t
1937 timeout_store(mddev_t *mddev, const char *buf, size_t len)
1938 {
1939         /* timeout can be set at any time */
1940         unsigned long timeout;
1941         int rv = strict_strtoul_scaled(buf, &timeout, 4);
1942         if (rv)
1943                 return rv;
1944
1945         /* just to make sure we don't overflow... */
1946         if (timeout >= LONG_MAX / HZ)
1947                 return -EINVAL;
1948
1949         timeout = timeout * HZ / 10000;
1950
1951         if (timeout >= MAX_SCHEDULE_TIMEOUT)
1952                 timeout = MAX_SCHEDULE_TIMEOUT-1;
1953         if (timeout < 1)
1954                 timeout = 1;
1955         mddev->bitmap_info.daemon_sleep = timeout;
1956         if (mddev->thread) {
1957                 /* if thread->timeout is MAX_SCHEDULE_TIMEOUT, then
1958                  * the bitmap is all clean and we don't need to
1959                  * adjust the timeout right now
1960                  */
1961                 if (mddev->thread->timeout < MAX_SCHEDULE_TIMEOUT) {
1962                         mddev->thread->timeout = timeout;
1963                         md_wakeup_thread(mddev->thread);
1964                 }
1965         }
1966         return len;
1967 }
1968
1969 static struct md_sysfs_entry bitmap_timeout =
1970 __ATTR(time_base, S_IRUGO|S_IWUSR, timeout_show, timeout_store);
1971
1972 static ssize_t
1973 backlog_show(mddev_t *mddev, char *page)
1974 {
1975         return sprintf(page, "%lu\n", mddev->bitmap_info.max_write_behind);
1976 }
1977
1978 static ssize_t
1979 backlog_store(mddev_t *mddev, const char *buf, size_t len)
1980 {
1981         unsigned long backlog;
1982         int rv = strict_strtoul(buf, 10, &backlog);
1983         if (rv)
1984                 return rv;
1985         if (backlog > COUNTER_MAX)
1986                 return -EINVAL;
1987         mddev->bitmap_info.max_write_behind = backlog;
1988         return len;
1989 }
1990
1991 static struct md_sysfs_entry bitmap_backlog =
1992 __ATTR(backlog, S_IRUGO|S_IWUSR, backlog_show, backlog_store);
1993
1994 static ssize_t
1995 chunksize_show(mddev_t *mddev, char *page)
1996 {
1997         return sprintf(page, "%lu\n", mddev->bitmap_info.chunksize);
1998 }
1999
2000 static ssize_t
2001 chunksize_store(mddev_t *mddev, const char *buf, size_t len)
2002 {
2003         /* Can only be changed when no bitmap is active */
2004         int rv;
2005         unsigned long csize;
2006         if (mddev->bitmap)
2007                 return -EBUSY;
2008         rv = strict_strtoul(buf, 10, &csize);
2009         if (rv)
2010                 return rv;
2011         if (csize < 512 ||
2012             !is_power_of_2(csize))
2013                 return -EINVAL;
2014         mddev->bitmap_info.chunksize = csize;
2015         return len;
2016 }
2017
2018 static struct md_sysfs_entry bitmap_chunksize =
2019 __ATTR(chunksize, S_IRUGO|S_IWUSR, chunksize_show, chunksize_store);
2020
2021 static ssize_t metadata_show(mddev_t *mddev, char *page)
2022 {
2023         return sprintf(page, "%s\n", (mddev->bitmap_info.external
2024                                       ? "external" : "internal"));
2025 }
2026
2027 static ssize_t metadata_store(mddev_t *mddev, const char *buf, size_t len)
2028 {
2029         if (mddev->bitmap ||
2030             mddev->bitmap_info.file ||
2031             mddev->bitmap_info.offset)
2032                 return -EBUSY;
2033         if (strncmp(buf, "external", 8) == 0)
2034                 mddev->bitmap_info.external = 1;
2035         else if (strncmp(buf, "internal", 8) == 0)
2036                 mddev->bitmap_info.external = 0;
2037         else
2038                 return -EINVAL;
2039         return len;
2040 }
2041
2042 static struct md_sysfs_entry bitmap_metadata =
2043 __ATTR(metadata, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
2044
2045 static ssize_t can_clear_show(mddev_t *mddev, char *page)
2046 {
2047         int len;
2048         if (mddev->bitmap)
2049                 len = sprintf(page, "%s\n", (mddev->bitmap->need_sync ?
2050                                              "false" : "true"));
2051         else
2052                 len = sprintf(page, "\n");
2053         return len;
2054 }
2055
2056 static ssize_t can_clear_store(mddev_t *mddev, const char *buf, size_t len)
2057 {
2058         if (mddev->bitmap == NULL)
2059                 return -ENOENT;
2060         if (strncmp(buf, "false", 5) == 0)
2061                 mddev->bitmap->need_sync = 1;
2062         else if (strncmp(buf, "true", 4) == 0) {
2063                 if (mddev->degraded)
2064                         return -EBUSY;
2065                 mddev->bitmap->need_sync = 0;
2066         } else
2067                 return -EINVAL;
2068         return len;
2069 }
2070
2071 static struct md_sysfs_entry bitmap_can_clear =
2072 __ATTR(can_clear, S_IRUGO|S_IWUSR, can_clear_show, can_clear_store);
2073
2074 static ssize_t
2075 behind_writes_used_show(mddev_t *mddev, char *page)
2076 {
2077         if (mddev->bitmap == NULL)
2078                 return sprintf(page, "0\n");
2079         return sprintf(page, "%lu\n",
2080                        mddev->bitmap->behind_writes_used);
2081 }
2082
2083 static ssize_t
2084 behind_writes_used_reset(mddev_t *mddev, const char *buf, size_t len)
2085 {
2086         if (mddev->bitmap)
2087                 mddev->bitmap->behind_writes_used = 0;
2088         return len;
2089 }
2090
2091 static struct md_sysfs_entry max_backlog_used =
2092 __ATTR(max_backlog_used, S_IRUGO | S_IWUSR,
2093        behind_writes_used_show, behind_writes_used_reset);
2094
2095 static struct attribute *md_bitmap_attrs[] = {
2096         &bitmap_location.attr,
2097         &bitmap_timeout.attr,
2098         &bitmap_backlog.attr,
2099         &bitmap_chunksize.attr,
2100         &bitmap_metadata.attr,
2101         &bitmap_can_clear.attr,
2102         &max_backlog_used.attr,
2103         NULL
2104 };
2105 struct attribute_group md_bitmap_group = {
2106         .name = "bitmap",
2107         .attrs = md_bitmap_attrs,
2108 };
2109