SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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  * wait if count gets too high, wake when it drops to half.
  17  */
  18
  19 #include <linux/blkdev.h>
  20 #include <linux/module.h>
  21 #include <linux/errno.h>
  22 #include <linux/slab.h>
  23 #include <linux/init.h>
  24 #include <linux/timer.h>
  25 #include <linux/sched.h>
  26 #include <linux/list.h>
  27 #include <linux/file.h>
  28 #include <linux/mount.h>
  29 #include <linux/buffer_head.h>
  30 #include "md.h"
  31 #include "bitmap.h"
  32
  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 //#define DPRINTK PRINTK /* set this NULL to avoid verbose debug output */
  55 #define DPRINTK(x...) do { } while(0)
  56
  57 #ifndef PRINTK
  58 #  if DEBUG > 0
  59 #    define PRINTK(x...) printk(KERN_DEBUG x)
  60 #  else
  61 #    define PRINTK(x...)
  62 #  endif
  63 #endif
  64
  65 static inline char * bmname(struct bitmap *bitmap)
  66 {
  67         return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
  68 }
  69
  70
  71 /*
  72  * just a placeholder - calls kmalloc for bitmap pages
  73  */
  74 static unsigned char *bitmap_alloc_page(struct bitmap *bitmap)
  75 {
  76         unsigned char *page;
  77
  78 #ifdef INJECT_FAULTS_1
  79         page = NULL;
  80 #else
  81         page = kmalloc(PAGE_SIZE, GFP_NOIO);
  82 #endif
  83         if (!page)
  84                 printk("%s: bitmap_alloc_page FAILED\n", bmname(bitmap));
  85         else
  86                 PRINTK("%s: bitmap_alloc_page: allocated page at %p\n",
  87                         bmname(bitmap), page);
  88         return page;
  89 }
  90
  91 /*
  92  * for now just a placeholder -- just calls kfree for bitmap pages
  93  */
  94 static void bitmap_free_page(struct bitmap *bitmap, unsigned char *page)
  95 {
  96         PRINTK("%s: bitmap_free_page: free page %p\n", bmname(bitmap), page);
  97         kfree(page);
  98 }
  99
 100 /*
 101  * check a page and, if necessary, allocate it (or hijack it if the alloc fails)
 102  *
 103  * 1) check to see if this page is allocated, if it's not then try to alloc
 104  * 2) if the alloc fails, set the page's hijacked flag so we'll use the
 105  *    page pointer directly as a counter
 106  *
 107  * if we find our page, we increment the page's refcount so that it stays
 108  * allocated while we're using it
 109  */
 110 static int bitmap_checkpage(struct bitmap *bitmap, unsigned long page, int create)
 111 __releases(bitmap->lock)
 112 __acquires(bitmap->lock)
 113 {
 114         unsigned char *mappage;
 115
 116         if (page >= bitmap->pages) {
 117                 /* This can happen if bitmap_start_sync goes beyond
 118                  * End-of-device while looking for a whole page.
 119                  * It is harmless.
 120                  */
 121                 return -EINVAL;
 122         }
 123
 124
 125         if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
 126                 return 0;
 127
 128         if (bitmap->bp[page].map) /* page is already allocated, just return */
 129                 return 0;
 130
 131         if (!create)
 132                 return -ENOENT;
 133
 134         spin_unlock_irq(&bitmap->lock);
 135
 136         /* this page has not been allocated yet */
 137
 138         if ((mappage = bitmap_alloc_page(bitmap)) == NULL) {
 139                 PRINTK("%s: bitmap map page allocation failed, hijacking\n",
 140                         bmname(bitmap));
 141                 /* failed - set the hijacked flag so that we can use the
 142                  * pointer as a counter */
 143                 spin_lock_irq(&bitmap->lock);
 144                 if (!bitmap->bp[page].map)
 145                         bitmap->bp[page].hijacked = 1;
 146                 goto out;
 147         }
 148
 149         /* got a page */
 150
 151         spin_lock_irq(&bitmap->lock);
 152
 153         /* recheck the page */
 154
 155         if (bitmap->bp[page].map || bitmap->bp[page].hijacked) {
 156                 /* somebody beat us to getting the page */
 157                 bitmap_free_page(bitmap, mappage);
 158                 return 0;
 159         }
 160
 161         /* no page was in place and we have one, so install it */
 162
 163         memset(mappage, 0, PAGE_SIZE);
 164         bitmap->bp[page].map = mappage;
 165         bitmap->missing_pages--;
 166 out:
 167         return 0;
 168 }
 169
 170
 171 /* if page is completely empty, put it back on the free list, or dealloc it */
 172 /* if page was hijacked, unmark the flag so it might get alloced next time */
 173 /* Note: lock should be held when calling this */
 174 static void bitmap_checkfree(struct bitmap *bitmap, unsigned long page)
 175 {
 176         char *ptr;
 177
 178         if (bitmap->bp[page].count) /* page is still busy */
 179                 return;
 180
 181         /* page is no longer in use, it can be released */
 182
 183         if (bitmap->bp[page].hijacked) { /* page was hijacked, undo this now */
 184                 bitmap->bp[page].hijacked = 0;
 185                 bitmap->bp[page].map = NULL;
 186                 return;
 187         }
 188
 189         /* normal case, free the page */
 190
 191 #if 0
 192 /* actually ... let's not.  We will probably need the page again exactly when
 193  * memory is tight and we are flusing to disk
 194  */
 195         return;
 196 #else
 197         ptr = bitmap->bp[page].map;
 198         bitmap->bp[page].map = NULL;
 199         bitmap->missing_pages++;
 200         bitmap_free_page(bitmap, ptr);
 201         return;
 202 #endif
 203 }
 204
 205
 206 /*
 207  * bitmap file handling - read and write the bitmap file and its superblock
 208  */
 209
 210 /*
 211  * basic page I/O operations
 212  */
 213
 214 /* IO operations when bitmap is stored near all superblocks */
 215 static struct page *read_sb_page(mddev_t *mddev, loff_t offset,
 216                                  struct page *page,
 217                                  unsigned long index, int size)
 218 {
 219         /* choose a good rdev and read the page from there */
 220
 221         mdk_rdev_t *rdev;
 222         sector_t target;
 223
 224         if (!page)
 225                 page = alloc_page(GFP_KERNEL);
 226         if (!page)
 227                 return ERR_PTR(-ENOMEM);
 228
 229         list_for_each_entry(rdev, &mddev->disks, same_set) {
 230                 if (! test_bit(In_sync, &rdev->flags)
 231                     || test_bit(Faulty, &rdev->flags))
 232                         continue;
 233
 234                 target = rdev->sb_start + offset + index * (PAGE_SIZE/512);
 235
 236                 if (sync_page_io(rdev->bdev, target,
 237                                  roundup(size, bdev_logical_block_size(rdev->bdev)),
 238                                  page, READ)) {
 239                         page->index = index;
 240                         attach_page_buffers(page, NULL); /* so that free_buffer will
 241                                                           * quietly no-op */
 242                         return page;
 243                 }
 244         }
 245         return ERR_PTR(-EIO);
 246
 247 }
 248
 249 static mdk_rdev_t *next_active_rdev(mdk_rdev_t *rdev, mddev_t *mddev)
 250 {
 251         /* Iterate the disks of an mddev, using rcu to protect access to the
 252          * linked list, and raising the refcount of devices we return to ensure
 253          * they don't disappear while in use.
 254          * As devices are only added or removed when raid_disk is < 0 and
 255          * nr_pending is 0 and In_sync is clear, the entries we return will
 256          * still be in the same position on the list when we re-enter
 257          * list_for_each_continue_rcu.
 258          */
 259         struct list_head *pos;
 260         rcu_read_lock();
 261         if (rdev == NULL)
 262                 /* start at the beginning */
 263                 pos = &mddev->disks;
 264         else {
 265                 /* release the previous rdev and start from there. */
 266                 rdev_dec_pending(rdev, mddev);
 267                 pos = &rdev->same_set;
 268         }
 269         list_for_each_continue_rcu(pos, &mddev->disks) {
 270                 rdev = list_entry(pos, mdk_rdev_t, same_set);
 271                 if (rdev->raid_disk >= 0 &&
 272                     !test_bit(Faulty, &rdev->flags)) {
 273                         /* this is a usable devices */
 274                         atomic_inc(&rdev->nr_pending);
 275                         rcu_read_unlock();
 276                         return rdev;
 277                 }
 278         }
 279         rcu_read_unlock();
 280         return NULL;
 281 }
 282
 283 static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
 284 {
 285         mdk_rdev_t *rdev = NULL;
 286         mddev_t *mddev = bitmap->mddev;
 287
 288         while ((rdev = next_active_rdev(rdev, mddev)) != NULL) {
 289                         int size = PAGE_SIZE;
 290                         loff_t offset = mddev->bitmap_info.offset;
 291                         if (page->index == bitmap->file_pages-1)
 292                                 size = roundup(bitmap->last_page_size,
 293                                                bdev_logical_block_size(rdev->bdev));
 294                         /* Just make sure we aren't corrupting data or
 295                          * metadata
 296                          */
 297                         if (mddev->external) {
 298                                 /* Bitmap could be anywhere. */
 299                                 if (rdev->sb_start + offset + (page->index *(PAGE_SIZE/512)) >
 300                                     rdev->data_offset &&
 301                                     rdev->sb_start + offset <
 302                                     rdev->data_offset + mddev->dev_sectors +
 303                                     (PAGE_SIZE/512))
 304                                         goto bad_alignment;
 305                         } else if (offset < 0) {
 306                                 /* DATA  BITMAP METADATA  */
 307                                 if (offset
 308                                     + (long)(page->index * (PAGE_SIZE/512))
 309                                     + size/512 > 0)
 310                                         /* bitmap runs in to metadata */
 311                                         goto bad_alignment;
 312                                 if (rdev->data_offset + mddev->dev_sectors
 313                                     > rdev->sb_start + offset)
 314                                         /* data runs in to bitmap */
 315                                         goto bad_alignment;
 316                         } else if (rdev->sb_start < rdev->data_offset) {
 317                                 /* METADATA BITMAP DATA */
 318                                 if (rdev->sb_start
 319                                     + offset
 320                                     + page->index*(PAGE_SIZE/512) + size/512
 321                                     > rdev->data_offset)
 322                                         /* bitmap runs in to data */
 323                                         goto bad_alignment;
 324                         } else {
 325                                 /* DATA METADATA BITMAP - no problems */
 326                         }
 327                         md_super_write(mddev, rdev,
 328                                        rdev->sb_start + offset
 329                                        + page->index * (PAGE_SIZE/512),
 330                                        size,
 331                                        page);
 332         }
 333
 334         if (wait)
 335                 md_super_wait(mddev);
 336         return 0;
 337
 338  bad_alignment:
 339         return -EINVAL;
 340 }
 341
 342 static void bitmap_file_kick(struct bitmap *bitmap);
 343 /*
 344  * write out a page to a file
 345  */
 346 static void write_page(struct bitmap *bitmap, struct page *page, int wait)
 347 {
 348         struct buffer_head *bh;
 349
 350         if (bitmap->file == NULL) {
 351                 switch (write_sb_page(bitmap, page, wait)) {
 352                 case -EINVAL:
 353                         bitmap->flags |= BITMAP_WRITE_ERROR;
 354                 }
 355         } else {
 356
 357                 bh = page_buffers(page);
 358
 359                 while (bh && bh->b_blocknr) {
 360                         atomic_inc(&bitmap->pending_writes);
 361                         set_buffer_locked(bh);
 362                         set_buffer_mapped(bh);
 363                         submit_bh(WRITE, bh);
 364                         bh = bh->b_this_page;
 365                 }
 366
 367                 if (wait) {
 368                         wait_event(bitmap->write_wait,
 369                                    atomic_read(&bitmap->pending_writes)==0);
 370                 }
 371         }
 372         if (bitmap->flags & BITMAP_WRITE_ERROR)
 373                 bitmap_file_kick(bitmap);
 374 }
 375
 376 static void end_bitmap_write(struct buffer_head *bh, int uptodate)
 377 {
 378         struct bitmap *bitmap = bh->b_private;
 379         unsigned long flags;
 380
 381         if (!uptodate) {
 382                 spin_lock_irqsave(&bitmap->lock, flags);
 383                 bitmap->flags |= BITMAP_WRITE_ERROR;
 384                 spin_unlock_irqrestore(&bitmap->lock, flags);
 385         }
 386         if (atomic_dec_and_test(&bitmap->pending_writes))
 387                 wake_up(&bitmap->write_wait);
 388 }
 389
 390 /* copied from buffer.c */
 391 static void
 392 __clear_page_buffers(struct page *page)
 393 {
 394         ClearPagePrivate(page);
 395         set_page_private(page, 0);
 396         page_cache_release(page);
 397 }
 398 static void free_buffers(struct page *page)
 399 {
 400         struct buffer_head *bh = page_buffers(page);
 401
 402         while (bh) {
 403                 struct buffer_head *next = bh->b_this_page;
 404                 free_buffer_head(bh);
 405                 bh = next;
 406         }
 407         __clear_page_buffers(page);
 408         put_page(page);
 409 }
 410
 411 /* read a page from a file.
 412  * We both read the page, and attach buffers to the page to record the
 413  * address of each block (using bmap).  These addresses will be used
 414  * to write the block later, completely bypassing the filesystem.
 415  * This usage is similar to how swap files are handled, and allows us
 416  * to write to a file with no concerns of memory allocation failing.
 417  */
 418 static struct page *read_page(struct file *file, unsigned long index,
 419                               struct bitmap *bitmap,
 420                               unsigned long count)
 421 {
 422         struct page *page = NULL;
 423         struct inode *inode = file->f_path.dentry->d_inode;
 424         struct buffer_head *bh;
 425         sector_t block;
 426
 427         PRINTK("read bitmap file (%dB @ %Lu)\n", (int)PAGE_SIZE,
 428                         (unsigned long long)index << PAGE_SHIFT);
 429
 430         page = alloc_page(GFP_KERNEL);
 431         if (!page)
 432                 page = ERR_PTR(-ENOMEM);
 433         if (IS_ERR(page))
 434                 goto out;
 435
 436         bh = alloc_page_buffers(page, 1<<inode->i_blkbits, 0);
 437         if (!bh) {
 438                 put_page(page);
 439                 page = ERR_PTR(-ENOMEM);
 440                 goto out;
 441         }
 442         attach_page_buffers(page, bh);
 443         block = index << (PAGE_SHIFT - inode->i_blkbits);
 444         while (bh) {
 445                 if (count == 0)
 446                         bh->b_blocknr = 0;
 447                 else {
 448                         bh->b_blocknr = bmap(inode, block);
 449                         if (bh->b_blocknr == 0) {
 450                                 /* Cannot use this file! */
 451                                 free_buffers(page);
 452                                 page = ERR_PTR(-EINVAL);
 453                                 goto out;
 454                         }
 455                         bh->b_bdev = inode->i_sb->s_bdev;
 456                         if (count < (1<<inode->i_blkbits))
 457                                 count = 0;
 458                         else
 459                                 count -= (1<<inode->i_blkbits);
 460
 461                         bh->b_end_io = end_bitmap_write;
 462                         bh->b_private = bitmap;
 463                         atomic_inc(&bitmap->pending_writes);
 464                         set_buffer_locked(bh);
 465                         set_buffer_mapped(bh);
 466                         submit_bh(READ, bh);
 467                 }
 468                 block++;
 469                 bh = bh->b_this_page;
 470         }
 471         page->index = index;
 472
 473         wait_event(bitmap->write_wait,
 474                    atomic_read(&bitmap->pending_writes)==0);
 475         if (bitmap->flags & BITMAP_WRITE_ERROR) {
 476                 free_buffers(page);
 477                 page = ERR_PTR(-EIO);
 478         }
 479 out:
 480         if (IS_ERR(page))
 481                 printk(KERN_ALERT "md: bitmap read error: (%dB @ %Lu): %ld\n",
 482                         (int)PAGE_SIZE,
 483                         (unsigned long long)index << PAGE_SHIFT,
 484                         PTR_ERR(page));
 485         return page;
 486 }
 487
 488 /*
 489  * bitmap file superblock operations
 490  */
 491
 492 /* update the event counter and sync the superblock to disk */
 493 void bitmap_update_sb(struct bitmap *bitmap)
 494 {
 495         bitmap_super_t *sb;
 496         unsigned long flags;
 497
 498         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
 499                 return;
 500         spin_lock_irqsave(&bitmap->lock, flags);
 501         if (!bitmap->sb_page) { /* no superblock */
 502                 spin_unlock_irqrestore(&bitmap->lock, flags);
 503                 return;
 504         }
 505         spin_unlock_irqrestore(&bitmap->lock, flags);
 506         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
 507         sb->events = cpu_to_le64(bitmap->mddev->events);
 508         if (bitmap->mddev->events < bitmap->events_cleared) {
 509                 /* rocking back to read-only */
 510                 bitmap->events_cleared = bitmap->mddev->events;
 511                 sb->events_cleared = cpu_to_le64(bitmap->events_cleared);
 512         }
 513         /* Just in case these have been changed via sysfs: */
 514         sb->daemon_sleep = cpu_to_le32(bitmap->mddev->bitmap_info.daemon_sleep/HZ);
 515         sb->write_behind = cpu_to_le32(bitmap->mddev->bitmap_info.max_write_behind);
 516         kunmap_atomic(sb, KM_USER0);
 517         write_page(bitmap, bitmap->sb_page, 1);
 518 }
 519
 520 /* print out the bitmap file superblock */
 521 void bitmap_print_sb(struct bitmap *bitmap)
 522 {
 523         bitmap_super_t *sb;
 524
 525         if (!bitmap || !bitmap->sb_page)
 526                 return;
 527         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
 528         printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
 529         printk(KERN_DEBUG "         magic: %08x\n", le32_to_cpu(sb->magic));
 530         printk(KERN_DEBUG "       version: %d\n", le32_to_cpu(sb->version));
 531         printk(KERN_DEBUG "          uuid: %08x.%08x.%08x.%08x\n",
 532                                         *(__u32 *)(sb->uuid+0),
 533                                         *(__u32 *)(sb->uuid+4),
 534                                         *(__u32 *)(sb->uuid+8),
 535                                         *(__u32 *)(sb->uuid+12));
 536         printk(KERN_DEBUG "        events: %llu\n",
 537                         (unsigned long long) le64_to_cpu(sb->events));
 538         printk(KERN_DEBUG "events cleared: %llu\n",
 539                         (unsigned long long) le64_to_cpu(sb->events_cleared));
 540         printk(KERN_DEBUG "         state: %08x\n", le32_to_cpu(sb->state));
 541         printk(KERN_DEBUG "     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
 542         printk(KERN_DEBUG "  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
 543         printk(KERN_DEBUG "     sync size: %llu KB\n",
 544                         (unsigned long long)le64_to_cpu(sb->sync_size)/2);
 545         printk(KERN_DEBUG "max write behind: %d\n", le32_to_cpu(sb->write_behind));
 546         kunmap_atomic(sb, KM_USER0);
 547 }
 548
 549 /* read the superblock from the bitmap file and initialize some bitmap fields */
 550 static int bitmap_read_sb(struct bitmap *bitmap)
 551 {
 552         char *reason = NULL;
 553         bitmap_super_t *sb;
 554         unsigned long chunksize, daemon_sleep, write_behind;
 555         unsigned long long events;
 556         int err = -EINVAL;
 557
 558         /* page 0 is the superblock, read it... */
 559         if (bitmap->file) {
 560                 loff_t isize = i_size_read(bitmap->file->f_mapping->host);
 561                 int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
 562
 563                 bitmap->sb_page = read_page(bitmap->file, 0, bitmap, bytes);
 564         } else {
 565                 bitmap->sb_page = read_sb_page(bitmap->mddev,
 566                                                bitmap->mddev->bitmap_info.offset,
 567                                                NULL,
 568                                                0, sizeof(bitmap_super_t));
 569         }
 570         if (IS_ERR(bitmap->sb_page)) {
 571                 err = PTR_ERR(bitmap->sb_page);
 572                 bitmap->sb_page = NULL;
 573                 return err;
 574         }
 575
 576         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
 577
 578         chunksize = le32_to_cpu(sb->chunksize);
 579         daemon_sleep = le32_to_cpu(sb->daemon_sleep) * HZ;
 580         write_behind = le32_to_cpu(sb->write_behind);
 581
 582         /* verify that the bitmap-specific fields are valid */
 583         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
 584                 reason = "bad magic";
 585         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
 586                  le32_to_cpu(sb->version) > BITMAP_MAJOR_HI)
 587                 reason = "unrecognized superblock version";
 588         else if (chunksize < 512)
 589                 reason = "bitmap chunksize too small";
 590         else if ((1 << ffz(~chunksize)) != chunksize)
 591                 reason = "bitmap chunksize not a power of 2";
 592         else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT)
 593                 reason = "daemon sleep period out of range";
 594         else if (write_behind > COUNTER_MAX)
 595                 reason = "write-behind limit out of range (0 - 16383)";
 596         if (reason) {
 597                 printk(KERN_INFO "%s: invalid bitmap file superblock: %s\n",
 598                         bmname(bitmap), reason);
 599                 goto out;
 600         }
 601
 602         /* keep the array size field of the bitmap superblock up to date */
 603         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 604
 605         if (!bitmap->mddev->persistent)
 606                 goto success;
 607
 608         /*
 609          * if we have a persistent array superblock, compare the
 610          * bitmap's UUID and event counter to the mddev's
 611          */
 612         if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
 613                 printk(KERN_INFO "%s: bitmap superblock UUID mismatch\n",
 614                         bmname(bitmap));
 615                 goto out;
 616         }
 617         events = le64_to_cpu(sb->events);
 618         if (events < bitmap->mddev->events) {
 619                 printk(KERN_INFO "%s: bitmap file is out of date (%llu < %llu) "
 620                         "-- forcing full recovery\n", bmname(bitmap), events,
 621                         (unsigned long long) bitmap->mddev->events);
 622                 sb->state |= cpu_to_le32(BITMAP_STALE);
 623         }
 624 success:
 625         /* assign fields using values from superblock */
 626         bitmap->mddev->bitmap_info.chunksize = chunksize;
 627         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 628         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 629         bitmap->flags |= le32_to_cpu(sb->state);
 630         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
 631                 bitmap->flags |= BITMAP_HOSTENDIAN;
 632         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
 633         if (sb->state & cpu_to_le32(BITMAP_STALE))
 634                 bitmap->events_cleared = bitmap->mddev->events;
 635         err = 0;
 636 out:
 637         kunmap_atomic(sb, KM_USER0);
 638         if (err)
 639                 bitmap_print_sb(bitmap);
 640         return err;
 641 }
 642
 643 enum bitmap_mask_op {
 644         MASK_SET,
 645         MASK_UNSET
 646 };
 647
 648 /* record the state of the bitmap in the superblock.  Return the old value */
 649 static int bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
 650                              enum bitmap_mask_op op)
 651 {
 652         bitmap_super_t *sb;
 653         unsigned long flags;
 654         int old;
 655
 656         spin_lock_irqsave(&bitmap->lock, flags);
 657         if (!bitmap->sb_page) { /* can't set the state */
 658                 spin_unlock_irqrestore(&bitmap->lock, flags);
 659                 return 0;
 660         }
 661         spin_unlock_irqrestore(&bitmap->lock, flags);
 662         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
 663         old = le32_to_cpu(sb->state) & bits;
 664         switch (op) {
 665                 case MASK_SET: sb->state |= cpu_to_le32(bits);
 666                                 break;
 667                 case MASK_UNSET: sb->state &= cpu_to_le32(~bits);
 668                                 break;
 669                 default: BUG();
 670         }
 671         kunmap_atomic(sb, KM_USER0);
 672         return old;
 673 }
 674
 675 /*
 676  * general bitmap file operations
 677  */
 678
 679 /* calculate the index of the page that contains this bit */
 680 static inline unsigned long file_page_index(unsigned long chunk)
 681 {
 682         return CHUNK_BIT_OFFSET(chunk) >> PAGE_BIT_SHIFT;
 683 }
 684
 685 /* calculate the (bit) offset of this bit within a page */
 686 static inline unsigned long file_page_offset(unsigned long chunk)
 687 {
 688         return CHUNK_BIT_OFFSET(chunk) & (PAGE_BITS - 1);
 689 }
 690
 691 /*
 692  * return a pointer to the page in the filemap that contains the given bit
 693  *
 694  * this lookup is complicated by the fact that the bitmap sb might be exactly
 695  * 1 page (e.g., x86) or less than 1 page -- so the bitmap might start on page
 696  * 0 or page 1
 697  */
 698 static inline struct page *filemap_get_page(struct bitmap *bitmap,
 699                                         unsigned long chunk)
 700 {
 701         if (file_page_index(chunk) >= bitmap->file_pages) return NULL;
 702         return bitmap->filemap[file_page_index(chunk) - file_page_index(0)];
 703 }
 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]->index != 0) /* 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 /*
 758  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
 759  * then it is no longer reliable, so we stop using it and we mark the file
 760  * as failed in the superblock
 761  */
 762 static void bitmap_file_kick(struct bitmap *bitmap)
 763 {
 764         char *path, *ptr = NULL;
 765
 766         if (bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET) == 0) {
 767                 bitmap_update_sb(bitmap);
 768
 769                 if (bitmap->file) {
 770                         path = kmalloc(PAGE_SIZE, GFP_KERNEL);
 771                         if (path)
 772                                 ptr = d_path(&bitmap->file->f_path, path,
 773                                              PAGE_SIZE);
 774
 775
 776                         printk(KERN_ALERT
 777                               "%s: kicking failed bitmap file %s from array!\n",
 778                               bmname(bitmap), IS_ERR(ptr) ? "" : ptr);
 779
 780                         kfree(path);
 781                 } else
 782                         printk(KERN_ALERT
 783                                "%s: disabling internal bitmap due to errors\n",
 784                                bmname(bitmap));
 785         }
 786
 787         bitmap_file_put(bitmap);
 788
 789         return;
 790 }
 791
 792 enum bitmap_page_attr {
 793         BITMAP_PAGE_DIRTY = 0, // there are set bits that need to be synced
 794         BITMAP_PAGE_CLEAN = 1, // there are bits that might need to be cleared
 795         BITMAP_PAGE_NEEDWRITE=2, // there are cleared bits that need to be synced
 796 };
 797
 798 static inline void set_page_attr(struct bitmap *bitmap, struct page *page,
 799                                 enum bitmap_page_attr attr)
 800 {
 801         __set_bit((page->index<<2) + attr, bitmap->filemap_attr);
 802 }
 803
 804 static inline void clear_page_attr(struct bitmap *bitmap, struct page *page,
 805                                 enum bitmap_page_attr attr)
 806 {
 807         __clear_bit((page->index<<2) + attr, bitmap->filemap_attr);
 808 }
 809
 810 static inline unsigned long test_page_attr(struct bitmap *bitmap, struct page *page,
 811                                            enum bitmap_page_attr attr)
 812 {
 813         return test_bit((page->index<<2) + attr, bitmap->filemap_attr);
 814 }
 815
 816 /*
 817  * bitmap_file_set_bit -- called before performing a write to the md device
 818  * to set (and eventually sync) a particular bit in the bitmap file
 819  *
 820  * we set the bit immediately, then we record the page number so that
 821  * when an unplug occurs, we can flush the dirty pages out to disk
 822  */
 823 static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 824 {
 825         unsigned long bit;
 826         struct page *page;
 827         void *kaddr;
 828         unsigned long chunk = block >> CHUNK_BLOCK_SHIFT(bitmap);
 829
 830         if (!bitmap->filemap) {
 831                 return;
 832         }
 833
 834         page = filemap_get_page(bitmap, chunk);
 835         if (!page) return;
 836         bit = file_page_offset(chunk);
 837
 838         /* set the bit */
 839         kaddr = kmap_atomic(page, KM_USER0);
 840         if (bitmap->flags & BITMAP_HOSTENDIAN)
 841                 set_bit(bit, kaddr);
 842         else
 843                 ext2_set_bit(bit, kaddr);
 844         kunmap_atomic(kaddr, KM_USER0);
 845         PRINTK("set file bit %lu page %lu\n", bit, page->index);
 846
 847         /* record page number so it gets flushed to disk when unplug occurs */
 848         set_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 849
 850 }
 851
 852 /* this gets called when the md device is ready to unplug its underlying
 853  * (slave) device queues -- before we let any writes go down, we need to
 854  * sync the dirty pages of the bitmap file to disk */
 855 void bitmap_unplug(struct bitmap *bitmap)
 856 {
 857         unsigned long i, flags;
 858         int dirty, need_write;
 859         struct page *page;
 860         int wait = 0;
 861
 862         if (!bitmap)
 863                 return;
 864
 865         /* look at each page to see if there are any set bits that need to be
 866          * flushed out to disk */
 867         for (i = 0; i < bitmap->file_pages; i++) {
 868                 spin_lock_irqsave(&bitmap->lock, flags);
 869                 if (!bitmap->filemap) {
 870                         spin_unlock_irqrestore(&bitmap->lock, flags);
 871                         return;
 872                 }
 873                 page = bitmap->filemap[i];
 874                 dirty = test_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 875                 need_write = test_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 876                 clear_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 877                 clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 878                 if (dirty)
 879                         wait = 1;
 880                 spin_unlock_irqrestore(&bitmap->lock, flags);
 881
 882                 if (dirty | need_write)
 883                         write_page(bitmap, page, 0);
 884         }
 885         if (wait) { /* if any writes were performed, we need to wait on them */
 886                 if (bitmap->file)
 887                         wait_event(bitmap->write_wait,
 888                                    atomic_read(&bitmap->pending_writes)==0);
 889                 else
 890                         md_super_wait(bitmap->mddev);
 891         }
 892         if (bitmap->flags & BITMAP_WRITE_ERROR)
 893                 bitmap_file_kick(bitmap);
 894 }
 895
 896 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
 897 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
 898  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
 899  * memory mapping of the bitmap file
 900  * Special cases:
 901  *   if there's no bitmap file, or if the bitmap file had been
 902  *   previously kicked from the array, we mark all the bits as
 903  *   1's in order to cause a full resync.
 904  *
 905  * We ignore all bits for sectors that end earlier than 'start'.
 906  * This is used when reading an out-of-date bitmap...
 907  */
 908 static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
 909 {
 910         unsigned long i, chunks, index, oldindex, bit;
 911         struct page *page = NULL, *oldpage = NULL;
 912         unsigned long num_pages, bit_cnt = 0;
 913         struct file *file;
 914         unsigned long bytes, offset;
 915         int outofdate;
 916         int ret = -ENOSPC;
 917         void *paddr;
 918
 919         chunks = bitmap->chunks;
 920         file = bitmap->file;
 921
 922         BUG_ON(!file && !bitmap->mddev->bitmap_info.offset);
 923
 924 #ifdef INJECT_FAULTS_3
 925         outofdate = 1;
 926 #else
 927         outofdate = bitmap->flags & BITMAP_STALE;
 928 #endif
 929         if (outofdate)
 930                 printk(KERN_INFO "%s: bitmap file is out of date, doing full "
 931                         "recovery\n", bmname(bitmap));
 932
 933         bytes = (chunks + 7) / 8;
 934
 935         num_pages = (bytes + sizeof(bitmap_super_t) + PAGE_SIZE - 1) / PAGE_SIZE;
 936
 937         if (file && i_size_read(file->f_mapping->host) < bytes + sizeof(bitmap_super_t)) {
 938                 printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
 939                         bmname(bitmap),
 940                         (unsigned long) i_size_read(file->f_mapping->host),
 941                         bytes + sizeof(bitmap_super_t));
 942                 goto err;
 943         }
 944
 945         ret = -ENOMEM;
 946
 947         bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
 948         if (!bitmap->filemap)
 949                 goto err;
 950
 951         /* We need 4 bits per page, rounded up to a multiple of sizeof(unsigned long) */
 952         bitmap->filemap_attr = kzalloc(
 953                 roundup( DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
 954                 GFP_KERNEL);
 955         if (!bitmap->filemap_attr)
 956                 goto err;
 957
 958         oldindex = ~0L;
 959
 960         for (i = 0; i < chunks; i++) {
 961                 int b;
 962                 index = file_page_index(i);
 963                 bit = file_page_offset(i);
 964                 if (index != oldindex) { /* this is a new page, read it in */
 965                         int count;
 966                         /* unmap the old page, we're done with it */
 967                         if (index == num_pages-1)
 968                                 count = bytes + sizeof(bitmap_super_t)
 969                                         - index * PAGE_SIZE;
 970                         else
 971                                 count = PAGE_SIZE;
 972                         if (index == 0) {
 973                                 /*
 974                                  * if we're here then the superblock page
 975                                  * contains some bits (PAGE_SIZE != sizeof sb)
 976                                  * we've already read it in, so just use it
 977                                  */
 978                                 page = bitmap->sb_page;
 979                                 offset = sizeof(bitmap_super_t);
 980                                 if (!file)
 981                                         read_sb_page(bitmap->mddev,
 982                                                      bitmap->mddev->bitmap_info.offset,
 983                                                      page,
 984                                                      index, count);
 985                         } else if (file) {
 986                                 page = read_page(file, index, bitmap, count);
 987                                 offset = 0;
 988                         } else {
 989                                 page = read_sb_page(bitmap->mddev,
 990                                                     bitmap->mddev->bitmap_info.offset,
 991                                                     NULL,
 992                                                     index, count);
 993                                 offset = 0;
 994                         }
 995                         if (IS_ERR(page)) { /* read error */
 996                                 ret = PTR_ERR(page);
 997                                 goto err;
 998                         }
 999
1000                         oldindex = index;
1001                         oldpage = page;
1002
1003                         bitmap->filemap[bitmap->file_pages++] = page;
1004                         bitmap->last_page_size = count;
1005
1006                         if (outofdate) {
1007                                 /*
1008                                  * if bitmap is out of date, dirty the
1009                                  * whole page and write it out
1010                                  */
1011                                 paddr = kmap_atomic(page, KM_USER0);
1012                                 memset(paddr + offset, 0xff,
1013                                        PAGE_SIZE - offset);
1014                                 kunmap_atomic(paddr, KM_USER0);
1015                                 write_page(bitmap, page, 1);
1016
1017                                 ret = -EIO;
1018                                 if (bitmap->flags & BITMAP_WRITE_ERROR)
1019                                         goto err;
1020                         }
1021                 }
1022                 paddr = kmap_atomic(page, KM_USER0);
1023                 if (bitmap->flags & BITMAP_HOSTENDIAN)
1024                         b = test_bit(bit, paddr);
1025                 else
1026                         b = ext2_test_bit(bit, paddr);
1027                 kunmap_atomic(paddr, KM_USER0);
1028                 if (b) {
1029                         /* if the disk bit is set, set the memory bit */
1030                         int needed = ((sector_t)(i+1) << (CHUNK_BLOCK_SHIFT(bitmap))
1031                                       >= start);
1032                         bitmap_set_memory_bits(bitmap,
1033                                                (sector_t)i << CHUNK_BLOCK_SHIFT(bitmap),
1034                                                needed);
1035                         bit_cnt++;
1036                         set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1037                 }
1038         }
1039
1040         /* everything went OK */
1041         ret = 0;
1042         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_UNSET);
1043
1044         if (bit_cnt) { /* Kick recovery if any bits were set */
1045                 set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
1046                 md_wakeup_thread(bitmap->mddev->thread);
1047         }
1048
1049         printk(KERN_INFO "%s: bitmap initialized from disk: "
1050                 "read %lu/%lu pages, set %lu bits\n",
1051                 bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt);
1052
1053         return 0;
1054
1055  err:
1056         printk(KERN_INFO "%s: bitmap initialisation failed: %d\n",
1057                bmname(bitmap), ret);
1058         return ret;
1059 }
1060
1061 void bitmap_write_all(struct bitmap *bitmap)
1062 {
1063         /* We don't actually write all bitmap blocks here,
1064          * just flag them as needing to be written
1065          */
1066         int i;
1067
1068         for (i=0; i < bitmap->file_pages; i++)
1069                 set_page_attr(bitmap, bitmap->filemap[i],
1070                               BITMAP_PAGE_NEEDWRITE);
1071 }
1072
1073
1074 static void bitmap_count_page(struct bitmap *bitmap, sector_t offset, int inc)
1075 {
1076         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1077         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1078         bitmap->bp[page].count += inc;
1079 /*
1080         if (page == 0) printk("count page 0, offset %llu: %d gives %d\n",
1081                               (unsigned long long)offset, inc, bitmap->bp[page].count);
1082 */
1083         bitmap_checkfree(bitmap, page);
1084 }
1085 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1086                                             sector_t offset, int *blocks,
1087                                             int create);
1088
1089 /*
1090  * bitmap daemon -- periodically wakes up to clean bits and flush pages
1091  *                      out to disk
1092  */
1093
1094 void bitmap_daemon_work(mddev_t *mddev)
1095 {
1096         struct bitmap *bitmap;
1097         unsigned long j;
1098         unsigned long flags;
1099         struct page *page = NULL, *lastpage = NULL;
1100         int blocks;
1101         void *paddr;
1102
1103         /* Use a mutex to guard daemon_work against
1104          * bitmap_destroy.
1105          */
1106         mutex_lock(&mddev->bitmap_info.mutex);
1107         bitmap = mddev->bitmap;
1108         if (bitmap == NULL) {
1109                 mutex_unlock(&mddev->bitmap_info.mutex);
1110                 return;
1111         }
1112         if (time_before(jiffies, bitmap->daemon_lastrun
1113                         + bitmap->mddev->bitmap_info.daemon_sleep))
1114                 goto done;
1115
1116         bitmap->daemon_lastrun = jiffies;
1117         if (bitmap->allclean) {
1118                 bitmap->mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1119                 goto done;
1120         }
1121         bitmap->allclean = 1;
1122
1123         spin_lock_irqsave(&bitmap->lock, flags);
1124         for (j = 0; j < bitmap->chunks; j++) {
1125                 bitmap_counter_t *bmc;
1126                 if (!bitmap->filemap)
1127                         /* error or shutdown */
1128                         break;
1129
1130                 page = filemap_get_page(bitmap, j);
1131
1132                 if (page != lastpage) {
1133                         /* skip this page unless it's marked as needing cleaning */
1134                         if (!test_page_attr(bitmap, page, BITMAP_PAGE_CLEAN)) {
1135                                 int need_write = test_page_attr(bitmap, page,
1136                                                                 BITMAP_PAGE_NEEDWRITE);
1137                                 if (need_write)
1138                                         clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
1139
1140                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1141                                 if (need_write) {
1142                                         write_page(bitmap, page, 0);
1143                                         bitmap->allclean = 0;
1144                                 }
1145                                 spin_lock_irqsave(&bitmap->lock, flags);
1146                                 j |= (PAGE_BITS - 1);
1147                                 continue;
1148                         }
1149
1150                         /* grab the new page, sync and release the old */
1151                         if (lastpage != NULL) {
1152                                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1153                                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1154                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1155                                         write_page(bitmap, lastpage, 0);
1156                                 } else {
1157                                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1158                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1159                                 }
1160                         } else
1161                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1162                         lastpage = page;
1163
1164                         /* We are possibly going to clear some bits, so make
1165                          * sure that events_cleared is up-to-date.
1166                          */
1167                         if (bitmap->need_sync) {
1168                                 bitmap_super_t *sb;
1169                                 bitmap->need_sync = 0;
1170                                 sb = kmap_atomic(bitmap->sb_page, KM_USER0);
1171                                 sb->events_cleared =
1172                                         cpu_to_le64(bitmap->events_cleared);
1173                                 kunmap_atomic(sb, KM_USER0);
1174                                 write_page(bitmap, bitmap->sb_page, 1);
1175                         }
1176                         spin_lock_irqsave(&bitmap->lock, flags);
1177                         clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1178                 }
1179                 bmc = bitmap_get_counter(bitmap,
1180                                          (sector_t)j << CHUNK_BLOCK_SHIFT(bitmap),
1181                                          &blocks, 0);
1182                 if (bmc) {
1183 /*
1184   if (j < 100) printk("bitmap: j=%lu, *bmc = 0x%x\n", j, *bmc);
1185 */
1186                         if (*bmc)
1187                                 bitmap->allclean = 0;
1188
1189                         if (*bmc == 2) {
1190                                 *bmc=1; /* maybe clear the bit next time */
1191                                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1192                         } else if (*bmc == 1) {
1193                                 /* we can clear the bit */
1194                                 *bmc = 0;
1195                                 bitmap_count_page(bitmap,
1196                                                   (sector_t)j << CHUNK_BLOCK_SHIFT(bitmap),
1197                                                   -1);
1198
1199                                 /* clear the bit */
1200                                 paddr = kmap_atomic(page, KM_USER0);
1201                                 if (bitmap->flags & BITMAP_HOSTENDIAN)
1202                                         clear_bit(file_page_offset(j), paddr);
1203                                 else
1204                                         ext2_clear_bit(file_page_offset(j), paddr);
1205                                 kunmap_atomic(paddr, KM_USER0);
1206                         }
1207                 } else
1208                         j |= PAGE_COUNTER_MASK;
1209         }
1210         spin_unlock_irqrestore(&bitmap->lock, flags);
1211
1212         /* now sync the final page */
1213         if (lastpage != NULL) {
1214                 spin_lock_irqsave(&bitmap->lock, flags);
1215                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1216                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1217                         spin_unlock_irqrestore(&bitmap->lock, flags);
1218                         write_page(bitmap, lastpage, 0);
1219                 } else {
1220                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1221                         spin_unlock_irqrestore(&bitmap->lock, flags);
1222                 }
1223         }
1224
1225  done:
1226         if (bitmap->allclean == 0)
1227                 bitmap->mddev->thread->timeout =
1228                         bitmap->mddev->bitmap_info.daemon_sleep;
1229         mutex_unlock(&mddev->bitmap_info.mutex);
1230 }
1231
1232 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1233                                             sector_t offset, int *blocks,
1234                                             int create)
1235 __releases(bitmap->lock)
1236 __acquires(bitmap->lock)
1237 {
1238         /* If 'create', we might release the lock and reclaim it.
1239          * The lock must have been taken with interrupts enabled.
1240          * If !create, we don't release the lock.
1241          */
1242         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1243         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1244         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1245         sector_t csize;
1246
1247         if (bitmap_checkpage(bitmap, page, create) < 0) {
1248                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1249                 *blocks = csize - (offset & (csize- 1));
1250                 return NULL;
1251         }
1252         /* now locked ... */
1253
1254         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1255                 /* should we use the first or second counter field
1256                  * of the hijacked pointer? */
1257                 int hi = (pageoff > PAGE_COUNTER_MASK);
1258                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap) +
1259                                           PAGE_COUNTER_SHIFT - 1);
1260                 *blocks = csize - (offset & (csize- 1));
1261                 return  &((bitmap_counter_t *)
1262                           &bitmap->bp[page].map)[hi];
1263         } else { /* page is allocated */
1264                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1265                 *blocks = csize - (offset & (csize- 1));
1266                 return (bitmap_counter_t *)
1267                         &(bitmap->bp[page].map[pageoff]);
1268         }
1269 }
1270
1271 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1272 {
1273         if (!bitmap) return 0;
1274
1275         if (behind) {
1276                 atomic_inc(&bitmap->behind_writes);
1277                 PRINTK(KERN_DEBUG "inc write-behind count %d/%d\n",
1278                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1279         }
1280
1281         while (sectors) {
1282                 int blocks;
1283                 bitmap_counter_t *bmc;
1284
1285                 spin_lock_irq(&bitmap->lock);
1286                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 1);
1287                 if (!bmc) {
1288                         spin_unlock_irq(&bitmap->lock);
1289                         return 0;
1290                 }
1291
1292                 if (unlikely((*bmc & COUNTER_MAX) == COUNTER_MAX)) {
1293                         DEFINE_WAIT(__wait);
1294                         /* note that it is safe to do the prepare_to_wait
1295                          * after the test as long as we do it before dropping
1296                          * the spinlock.
1297                          */
1298                         prepare_to_wait(&bitmap->overflow_wait, &__wait,
1299                                         TASK_UNINTERRUPTIBLE);
1300                         spin_unlock_irq(&bitmap->lock);
1301                         blk_unplug(bitmap->mddev->queue);
1302                         schedule();
1303                         finish_wait(&bitmap->overflow_wait, &__wait);
1304                         continue;
1305                 }
1306
1307                 switch(*bmc) {
1308                 case 0:
1309                         bitmap_file_set_bit(bitmap, offset);
1310                         bitmap_count_page(bitmap,offset, 1);
1311                         blk_plug_device_unlocked(bitmap->mddev->queue);
1312                         /* fall through */
1313                 case 1:
1314                         *bmc = 2;
1315                 }
1316
1317                 (*bmc)++;
1318
1319                 spin_unlock_irq(&bitmap->lock);
1320
1321                 offset += blocks;
1322                 if (sectors > blocks)
1323                         sectors -= blocks;
1324                 else sectors = 0;
1325         }
1326         bitmap->allclean = 0;
1327         return 0;
1328 }
1329
1330 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1331                      int success, int behind)
1332 {
1333         if (!bitmap) return;
1334         if (behind) {
1335                 atomic_dec(&bitmap->behind_writes);
1336                 PRINTK(KERN_DEBUG "dec write-behind count %d/%d\n",
1337                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1338         }
1339         if (bitmap->mddev->degraded)
1340                 /* Never clear bits or update events_cleared when degraded */
1341                 success = 0;
1342
1343         while (sectors) {
1344                 int blocks;
1345                 unsigned long flags;
1346                 bitmap_counter_t *bmc;
1347
1348                 spin_lock_irqsave(&bitmap->lock, flags);
1349                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 0);
1350                 if (!bmc) {
1351                         spin_unlock_irqrestore(&bitmap->lock, flags);
1352                         return;
1353                 }
1354
1355                 if (success &&
1356                     bitmap->events_cleared < bitmap->mddev->events) {
1357                         bitmap->events_cleared = bitmap->mddev->events;
1358                         bitmap->need_sync = 1;
1359                 }
1360
1361                 if (!success && ! (*bmc & NEEDED_MASK))
1362                         *bmc |= NEEDED_MASK;
1363
1364                 if ((*bmc & COUNTER_MAX) == COUNTER_MAX)
1365                         wake_up(&bitmap->overflow_wait);
1366
1367                 (*bmc)--;
1368                 if (*bmc <= 2) {
1369                         set_page_attr(bitmap,
1370                                       filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1371                                       BITMAP_PAGE_CLEAN);
1372                 }
1373                 spin_unlock_irqrestore(&bitmap->lock, flags);
1374                 offset += blocks;
1375                 if (sectors > blocks)
1376                         sectors -= blocks;
1377                 else sectors = 0;
1378         }
1379 }
1380
1381 static int __bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
1382                                int degraded)
1383 {
1384         bitmap_counter_t *bmc;
1385         int rv;
1386         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1387                 *blocks = 1024;
1388                 return 1; /* always resync if no bitmap */
1389         }
1390         spin_lock_irq(&bitmap->lock);
1391         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1392         rv = 0;
1393         if (bmc) {
1394                 /* locked */
1395                 if (RESYNC(*bmc))
1396                         rv = 1;
1397                 else if (NEEDED(*bmc)) {
1398                         rv = 1;
1399                         if (!degraded) { /* don't set/clear bits if degraded */
1400                                 *bmc |= RESYNC_MASK;
1401                                 *bmc &= ~NEEDED_MASK;
1402                         }
1403                 }
1404         }
1405         spin_unlock_irq(&bitmap->lock);
1406         bitmap->allclean = 0;
1407         return rv;
1408 }
1409
1410 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
1411                       int degraded)
1412 {
1413         /* bitmap_start_sync must always report on multiples of whole
1414          * pages, otherwise resync (which is very PAGE_SIZE based) will
1415          * get confused.
1416          * So call __bitmap_start_sync repeatedly (if needed) until
1417          * At least PAGE_SIZE>>9 blocks are covered.
1418          * Return the 'or' of the result.
1419          */
1420         int rv = 0;
1421         int blocks1;
1422
1423         *blocks = 0;
1424         while (*blocks < (PAGE_SIZE>>9)) {
1425                 rv |= __bitmap_start_sync(bitmap, offset,
1426                                           &blocks1, degraded);
1427                 offset += blocks1;
1428                 *blocks += blocks1;
1429         }
1430         return rv;
1431 }
1432
1433 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int aborted)
1434 {
1435         bitmap_counter_t *bmc;
1436         unsigned long flags;
1437 /*
1438         if (offset == 0) printk("bitmap_end_sync 0 (%d)\n", aborted);
1439 */      if (bitmap == NULL) {
1440                 *blocks = 1024;
1441                 return;
1442         }
1443         spin_lock_irqsave(&bitmap->lock, flags);
1444         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1445         if (bmc == NULL)
1446                 goto unlock;
1447         /* locked */
1448 /*
1449         if (offset == 0) printk("bitmap_end sync found 0x%x, blocks %d\n", *bmc, *blocks);
1450 */
1451         if (RESYNC(*bmc)) {
1452                 *bmc &= ~RESYNC_MASK;
1453
1454                 if (!NEEDED(*bmc) && aborted)
1455                         *bmc |= NEEDED_MASK;
1456                 else {
1457                         if (*bmc <= 2) {
1458                                 set_page_attr(bitmap,
1459                                               filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1460                                               BITMAP_PAGE_CLEAN);
1461                         }
1462                 }
1463         }
1464  unlock:
1465         spin_unlock_irqrestore(&bitmap->lock, flags);
1466         bitmap->allclean = 0;
1467 }
1468
1469 void bitmap_close_sync(struct bitmap *bitmap)
1470 {
1471         /* Sync has finished, and any bitmap chunks that weren't synced
1472          * properly have been aborted.  It remains to us to clear the
1473          * RESYNC bit wherever it is still on
1474          */
1475         sector_t sector = 0;
1476         int blocks;
1477         if (!bitmap)
1478                 return;
1479         while (sector < bitmap->mddev->resync_max_sectors) {
1480                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1481                 sector += blocks;
1482         }
1483 }
1484
1485 void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector)
1486 {
1487         sector_t s = 0;
1488         int blocks;
1489
1490         if (!bitmap)
1491                 return;
1492         if (sector == 0) {
1493                 bitmap->last_end_sync = jiffies;
1494                 return;
1495         }
1496         if (time_before(jiffies, (bitmap->last_end_sync
1497                                   + bitmap->mddev->bitmap_info.daemon_sleep)))
1498                 return;
1499         wait_event(bitmap->mddev->recovery_wait,
1500                    atomic_read(&bitmap->mddev->recovery_active) == 0);
1501
1502         bitmap->mddev->curr_resync_completed = bitmap->mddev->curr_resync;
1503         set_bit(MD_CHANGE_CLEAN, &bitmap->mddev->flags);
1504         sector &= ~((1ULL << CHUNK_BLOCK_SHIFT(bitmap)) - 1);
1505         s = 0;
1506         while (s < sector && s < bitmap->mddev->resync_max_sectors) {
1507                 bitmap_end_sync(bitmap, s, &blocks, 0);
1508                 s += blocks;
1509         }
1510         bitmap->last_end_sync = jiffies;
1511         sysfs_notify(&bitmap->mddev->kobj, NULL, "sync_completed");
1512 }
1513
1514 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1515 {
1516         /* For each chunk covered by any of these sectors, set the
1517          * counter to 1 and set resync_needed.  They should all
1518          * be 0 at this point
1519          */
1520
1521         int secs;
1522         bitmap_counter_t *bmc;
1523         spin_lock_irq(&bitmap->lock);
1524         bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
1525         if (!bmc) {
1526                 spin_unlock_irq(&bitmap->lock);
1527                 return;
1528         }
1529         if (! *bmc) {
1530                 struct page *page;
1531                 *bmc = 1 | (needed?NEEDED_MASK:0);
1532                 bitmap_count_page(bitmap, offset, 1);
1533                 page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));
1534                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1535         }
1536         spin_unlock_irq(&bitmap->lock);
1537         bitmap->allclean = 0;
1538 }
1539
1540 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
1541 void bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1542 {
1543         unsigned long chunk;
1544
1545         for (chunk = s; chunk <= e; chunk++) {
1546                 sector_t sec = (sector_t)chunk << CHUNK_BLOCK_SHIFT(bitmap);
1547                 bitmap_set_memory_bits(bitmap, sec, 1);
1548                 bitmap_file_set_bit(bitmap, sec);
1549         }
1550 }
1551
1552 /*
1553  * flush out any pending updates
1554  */
1555 void bitmap_flush(mddev_t *mddev)
1556 {
1557         struct bitmap *bitmap = mddev->bitmap;
1558         long sleep;
1559
1560         if (!bitmap) /* there was no bitmap */
1561                 return;
1562
1563         /* run the daemon_work three time to ensure everything is flushed
1564          * that can be
1565          */
1566         sleep = mddev->bitmap_info.daemon_sleep * 2;
1567         bitmap->daemon_lastrun -= sleep;
1568         bitmap_daemon_work(mddev);
1569         bitmap->daemon_lastrun -= sleep;
1570         bitmap_daemon_work(mddev);
1571         bitmap->daemon_lastrun -= sleep;
1572         bitmap_daemon_work(mddev);
1573         bitmap_update_sb(bitmap);
1574 }
1575
1576 /*
1577  * free memory that was allocated
1578  */
1579 static void bitmap_free(struct bitmap *bitmap)
1580 {
1581         unsigned long k, pages;
1582         struct bitmap_page *bp;
1583
1584         if (!bitmap) /* there was no bitmap */
1585                 return;
1586
1587         /* release the bitmap file and kill the daemon */
1588         bitmap_file_put(bitmap);
1589
1590         bp = bitmap->bp;
1591         pages = bitmap->pages;
1592
1593         /* free all allocated memory */
1594
1595         if (bp) /* deallocate the page memory */
1596                 for (k = 0; k < pages; k++)
1597                         if (bp[k].map && !bp[k].hijacked)
1598                                 kfree(bp[k].map);
1599         kfree(bp);
1600         kfree(bitmap);
1601 }
1602
1603 void bitmap_destroy(mddev_t *mddev)
1604 {
1605         struct bitmap *bitmap = mddev->bitmap;
1606
1607         if (!bitmap) /* there was no bitmap */
1608                 return;
1609
1610         mutex_lock(&mddev->bitmap_info.mutex);
1611         mddev->bitmap = NULL; /* disconnect from the md device */
1612         mutex_unlock(&mddev->bitmap_info.mutex);
1613         if (mddev->thread)
1614                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1615
1616         bitmap_free(bitmap);
1617 }
1618
1619 /*
1620  * initialize the bitmap structure
1621  * if this returns an error, bitmap_destroy must be called to do clean up
1622  */
1623 int bitmap_create(mddev_t *mddev)
1624 {
1625         struct bitmap *bitmap;
1626         sector_t blocks = mddev->resync_max_sectors;
1627         unsigned long chunks;
1628         unsigned long pages;
1629         struct file *file = mddev->bitmap_info.file;
1630         int err;
1631         sector_t start;
1632
1633         BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
1634
1635         if (!file && !mddev->bitmap_info.offset) /* bitmap disabled, nothing to do */
1636                 return 0;
1637
1638         BUG_ON(file && mddev->bitmap_info.offset);
1639
1640         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1641         if (!bitmap)
1642                 return -ENOMEM;
1643
1644         spin_lock_init(&bitmap->lock);
1645         atomic_set(&bitmap->pending_writes, 0);
1646         init_waitqueue_head(&bitmap->write_wait);
1647         init_waitqueue_head(&bitmap->overflow_wait);
1648
1649         bitmap->mddev = mddev;
1650
1651         bitmap->file = file;
1652         if (file) {
1653                 get_file(file);
1654                 /* As future accesses to this file will use bmap,
1655                  * and bypass the page cache, we must sync the file
1656                  * first.
1657                  */
1658                 vfs_fsync(file, file->f_dentry, 1);
1659         }
1660         /* read superblock from bitmap file (this sets mddev->bitmap_info.chunksize) */
1661         err = bitmap_read_sb(bitmap);
1662         if (err)
1663                 goto error;
1664
1665         bitmap->daemon_lastrun = jiffies;
1666         bitmap->chunkshift = ffz(~mddev->bitmap_info.chunksize);
1667
1668         /* now that chunksize and chunkshift are set, we can use these macros */
1669         chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) >>
1670                         CHUNK_BLOCK_SHIFT(bitmap);
1671         pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
1672
1673         BUG_ON(!pages);
1674
1675         bitmap->chunks = chunks;
1676         bitmap->pages = pages;
1677         bitmap->missing_pages = pages;
1678         bitmap->counter_bits = COUNTER_BITS;
1679
1680         bitmap->syncchunk = ~0UL;
1681
1682 #ifdef INJECT_FATAL_FAULT_1
1683         bitmap->bp = NULL;
1684 #else
1685         bitmap->bp = kzalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
1686 #endif
1687         err = -ENOMEM;
1688         if (!bitmap->bp)
1689                 goto error;
1690
1691         /* now that we have some pages available, initialize the in-memory
1692          * bitmap from the on-disk bitmap */
1693         start = 0;
1694         if (mddev->degraded == 0
1695             || bitmap->events_cleared == mddev->events)
1696                 /* no need to keep dirty bits to optimise a re-add of a missing device */
1697                 start = mddev->recovery_cp;
1698         err = bitmap_init_from_disk(bitmap, start);
1699
1700         if (err)
1701                 goto error;
1702
1703         printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
1704                 pages, bmname(bitmap));
1705
1706         mddev->bitmap = bitmap;
1707
1708         mddev->thread->timeout = mddev->bitmap_info.daemon_sleep;
1709         md_wakeup_thread(mddev->thread);
1710
1711         bitmap_update_sb(bitmap);
1712
1713         return (bitmap->flags & BITMAP_WRITE_ERROR) ? -EIO : 0;
1714
1715  error:
1716         bitmap_free(bitmap);
1717         return err;
1718 }
1719
1720 static ssize_t
1721 location_show(mddev_t *mddev, char *page)
1722 {
1723         ssize_t len;
1724         if (mddev->bitmap_info.file) {
1725                 len = sprintf(page, "file");
1726         } else if (mddev->bitmap_info.offset) {
1727                 len = sprintf(page, "%+lld", (long long)mddev->bitmap_info.offset);
1728         } else
1729                 len = sprintf(page, "none");
1730         len += sprintf(page+len, "\n");
1731         return len;
1732 }
1733
1734 static ssize_t
1735 location_store(mddev_t *mddev, const char *buf, size_t len)
1736 {
1737
1738         if (mddev->pers) {
1739                 if (!mddev->pers->quiesce)
1740                         return -EBUSY;
1741                 if (mddev->recovery || mddev->sync_thread)
1742                         return -EBUSY;
1743         }
1744
1745         if (mddev->bitmap || mddev->bitmap_info.file ||
1746             mddev->bitmap_info.offset) {
1747                 /* bitmap already configured.  Only option is to clear it */
1748                 if (strncmp(buf, "none", 4) != 0)
1749                         return -EBUSY;
1750                 if (mddev->pers) {
1751                         mddev->pers->quiesce(mddev, 1);
1752                         bitmap_destroy(mddev);
1753                         mddev->pers->quiesce(mddev, 0);
1754                 }
1755                 mddev->bitmap_info.offset = 0;
1756                 if (mddev->bitmap_info.file) {
1757                         struct file *f = mddev->bitmap_info.file;
1758                         mddev->bitmap_info.file = NULL;
1759                         restore_bitmap_write_access(f);
1760                         fput(f);
1761                 }
1762         } else {
1763                 /* No bitmap, OK to set a location */
1764                 long long offset;
1765                 if (strncmp(buf, "none", 4) == 0)
1766                         /* nothing to be done */;
1767                 else if (strncmp(buf, "file:", 5) == 0) {
1768                         /* Not supported yet */
1769                         return -EINVAL;
1770                 } else {
1771                         int rv;
1772                         if (buf[0] == '+')
1773                                 rv = strict_strtoll(buf+1, 10, &offset);
1774                         else
1775                                 rv = strict_strtoll(buf, 10, &offset);
1776                         if (rv)
1777                                 return rv;
1778                         if (offset == 0)
1779                                 return -EINVAL;
1780                         if (mddev->major_version == 0 &&
1781                             offset != mddev->bitmap_info.default_offset)
1782                                 return -EINVAL;
1783                         mddev->bitmap_info.offset = offset;
1784                         if (mddev->pers) {
1785                                 mddev->pers->quiesce(mddev, 1);
1786                                 rv = bitmap_create(mddev);
1787                                 if (rv) {
1788                                         bitmap_destroy(mddev);
1789                                         mddev->bitmap_info.offset = 0;
1790                                 }
1791                                 mddev->pers->quiesce(mddev, 0);
1792                                 if (rv)
1793                                         return rv;
1794                         }
1795                 }
1796         }
1797         if (!mddev->external) {
1798                 /* Ensure new bitmap info is stored in
1799                  * metadata promptly.
1800                  */
1801                 set_bit(MD_CHANGE_DEVS, &mddev->flags);
1802                 md_wakeup_thread(mddev->thread);
1803         }
1804         return len;
1805 }
1806
1807 static struct md_sysfs_entry bitmap_location =
1808 __ATTR(location, S_IRUGO|S_IWUSR, location_show, location_store);
1809
1810 static ssize_t
1811 timeout_show(mddev_t *mddev, char *page)
1812 {
1813         ssize_t len;
1814         unsigned long secs = mddev->bitmap_info.daemon_sleep / HZ;
1815         unsigned long jifs = mddev->bitmap_info.daemon_sleep % HZ;
1816
1817         len = sprintf(page, "%lu", secs);
1818         if (jifs)
1819                 len += sprintf(page+len, ".%03u", jiffies_to_msecs(jifs));
1820         len += sprintf(page+len, "\n");
1821         return len;
1822 }
1823
1824 static ssize_t
1825 timeout_store(mddev_t *mddev, const char *buf, size_t len)
1826 {
1827         /* timeout can be set at any time */
1828         unsigned long timeout;
1829         int rv = strict_strtoul_scaled(buf, &timeout, 4);
1830         if (rv)
1831                 return rv;
1832
1833         /* just to make sure we don't overflow... */
1834         if (timeout >= LONG_MAX / HZ)
1835                 return -EINVAL;
1836
1837         timeout = timeout * HZ / 10000;
1838
1839         if (timeout >= MAX_SCHEDULE_TIMEOUT)
1840                 timeout = MAX_SCHEDULE_TIMEOUT-1;
1841         if (timeout < 1)
1842                 timeout = 1;
1843         mddev->bitmap_info.daemon_sleep = timeout;
1844         if (mddev->thread) {
1845                 /* if thread->timeout is MAX_SCHEDULE_TIMEOUT, then
1846                  * the bitmap is all clean and we don't need to
1847                  * adjust the timeout right now
1848                  */
1849                 if (mddev->thread->timeout < MAX_SCHEDULE_TIMEOUT) {
1850                         mddev->thread->timeout = timeout;
1851                         md_wakeup_thread(mddev->thread);
1852                 }
1853         }
1854         return len;
1855 }
1856
1857 static struct md_sysfs_entry bitmap_timeout =
1858 __ATTR(time_base, S_IRUGO|S_IWUSR, timeout_show, timeout_store);
1859
1860 static ssize_t
1861 backlog_show(mddev_t *mddev, char *page)
1862 {
1863         return sprintf(page, "%lu\n", mddev->bitmap_info.max_write_behind);
1864 }
1865
1866 static ssize_t
1867 backlog_store(mddev_t *mddev, const char *buf, size_t len)
1868 {
1869         unsigned long backlog;
1870         int rv = strict_strtoul(buf, 10, &backlog);
1871         if (rv)
1872                 return rv;
1873         if (backlog > COUNTER_MAX)
1874                 return -EINVAL;
1875         mddev->bitmap_info.max_write_behind = backlog;
1876         return len;
1877 }
1878
1879 static struct md_sysfs_entry bitmap_backlog =
1880 __ATTR(backlog, S_IRUGO|S_IWUSR, backlog_show, backlog_store);
1881
1882 static ssize_t
1883 chunksize_show(mddev_t *mddev, char *page)
1884 {
1885         return sprintf(page, "%lu\n", mddev->bitmap_info.chunksize);
1886 }
1887
1888 static ssize_t
1889 chunksize_store(mddev_t *mddev, const char *buf, size_t len)
1890 {
1891         /* Can only be changed when no bitmap is active */
1892         int rv;
1893         unsigned long csize;
1894         if (mddev->bitmap)
1895                 return -EBUSY;
1896         rv = strict_strtoul(buf, 10, &csize);
1897         if (rv)
1898                 return rv;
1899         if (csize < 512 ||
1900             !is_power_of_2(csize))
1901                 return -EINVAL;
1902         mddev->bitmap_info.chunksize = csize;
1903         return len;
1904 }
1905
1906 static struct md_sysfs_entry bitmap_chunksize =
1907 __ATTR(chunksize, S_IRUGO|S_IWUSR, chunksize_show, chunksize_store);
1908
1909 static struct attribute *md_bitmap_attrs[] = {
1910         &bitmap_location.attr,
1911         &bitmap_timeout.attr,
1912         &bitmap_backlog.attr,
1913         &bitmap_chunksize.attr,
1914         NULL
1915 };
1916 struct attribute_group md_bitmap_group = {
1917         .name = "bitmap",
1918         .attrs = md_bitmap_attrs,
1919 };
1920
1921
1922 /* the bitmap API -- for raid personalities */
1923 EXPORT_SYMBOL(bitmap_startwrite);
1924 EXPORT_SYMBOL(bitmap_endwrite);
1925 EXPORT_SYMBOL(bitmap_start_sync);
1926 EXPORT_SYMBOL(bitmap_end_sync);
1927 EXPORT_SYMBOL(bitmap_unplug);
1928 EXPORT_SYMBOL(bitmap_close_sync);
1929 EXPORT_SYMBOL(bitmap_cond_end_sync);