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, 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 | REQ_UNPLUG | REQ_SYNC, 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                                         page = read_sb_page(
1004                                                 bitmap->mddev,
1005                                                 bitmap->mddev->bitmap_info.offset,
1006                                                 page,
1007                                                 index, count);
1008                         } else if (file) {
1009                                 page = read_page(file, index, bitmap, count);
1010                                 offset = 0;
1011                         } else {
1012                                 page = read_sb_page(bitmap->mddev,
1013                                                     bitmap->mddev->bitmap_info.offset,
1014                                                     NULL,
1015                                                     index, count);
1016                                 offset = 0;
1017                         }
1018                         if (IS_ERR(page)) { /* read error */
1019                                 ret = PTR_ERR(page);
1020                                 goto err;
1021                         }
1022
1023                         oldindex = index;
1024                         oldpage = page;
1025
1026                         bitmap->filemap[bitmap->file_pages++] = page;
1027                         bitmap->last_page_size = count;
1028
1029                         if (outofdate) {
1030                                 /*
1031                                  * if bitmap is out of date, dirty the
1032                                  * whole page and write it out
1033                                  */
1034                                 paddr = kmap_atomic(page, KM_USER0);
1035                                 memset(paddr + offset, 0xff,
1036                                        PAGE_SIZE - offset);
1037                                 kunmap_atomic(paddr, KM_USER0);
1038                                 write_page(bitmap, page, 1);
1039
1040                                 ret = -EIO;
1041                                 if (bitmap->flags & BITMAP_WRITE_ERROR)
1042                                         goto err;
1043                         }
1044                 }
1045                 paddr = kmap_atomic(page, KM_USER0);
1046                 if (bitmap->flags & BITMAP_HOSTENDIAN)
1047                         b = test_bit(bit, paddr);
1048                 else
1049                         b = ext2_test_bit(bit, paddr);
1050                 kunmap_atomic(paddr, KM_USER0);
1051                 if (b) {
1052                         /* if the disk bit is set, set the memory bit */
1053                         int needed = ((sector_t)(i+1) << (CHUNK_BLOCK_SHIFT(bitmap))
1054                                       >= start);
1055                         bitmap_set_memory_bits(bitmap,
1056                                                (sector_t)i << CHUNK_BLOCK_SHIFT(bitmap),
1057                                                needed);
1058                         bit_cnt++;
1059                         set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1060                 }
1061         }
1062
1063         /* everything went OK */
1064         ret = 0;
1065         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_UNSET);
1066
1067         if (bit_cnt) { /* Kick recovery if any bits were set */
1068                 set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
1069                 md_wakeup_thread(bitmap->mddev->thread);
1070         }
1071
1072         printk(KERN_INFO "%s: bitmap initialized from disk: "
1073                 "read %lu/%lu pages, set %lu bits\n",
1074                 bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt);
1075
1076         return 0;
1077
1078  err:
1079         printk(KERN_INFO "%s: bitmap initialisation failed: %d\n",
1080                bmname(bitmap), ret);
1081         return ret;
1082 }
1083
1084 void bitmap_write_all(struct bitmap *bitmap)
1085 {
1086         /* We don't actually write all bitmap blocks here,
1087          * just flag them as needing to be written
1088          */
1089         int i;
1090
1091         for (i = 0; i < bitmap->file_pages; i++)
1092                 set_page_attr(bitmap, bitmap->filemap[i],
1093                               BITMAP_PAGE_NEEDWRITE);
1094 }
1095
1096 static void bitmap_count_page(struct bitmap *bitmap, sector_t offset, int inc)
1097 {
1098         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1099         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1100         bitmap->bp[page].count += inc;
1101         bitmap_checkfree(bitmap, page);
1102 }
1103 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1104                                             sector_t offset, sector_t *blocks,
1105                                             int create);
1106
1107 /*
1108  * bitmap daemon -- periodically wakes up to clean bits and flush pages
1109  *                      out to disk
1110  */
1111
1112 void bitmap_daemon_work(mddev_t *mddev)
1113 {
1114         struct bitmap *bitmap;
1115         unsigned long j;
1116         unsigned long flags;
1117         struct page *page = NULL, *lastpage = NULL;
1118         sector_t blocks;
1119         void *paddr;
1120         struct dm_dirty_log *log = mddev->bitmap_info.log;
1121
1122         /* Use a mutex to guard daemon_work against
1123          * bitmap_destroy.
1124          */
1125         mutex_lock(&mddev->bitmap_info.mutex);
1126         bitmap = mddev->bitmap;
1127         if (bitmap == NULL) {
1128                 mutex_unlock(&mddev->bitmap_info.mutex);
1129                 return;
1130         }
1131         if (time_before(jiffies, bitmap->daemon_lastrun
1132                         + bitmap->mddev->bitmap_info.daemon_sleep))
1133                 goto done;
1134
1135         bitmap->daemon_lastrun = jiffies;
1136         if (bitmap->allclean) {
1137                 bitmap->mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1138                 goto done;
1139         }
1140         bitmap->allclean = 1;
1141
1142         spin_lock_irqsave(&bitmap->lock, flags);
1143         for (j = 0; j < bitmap->chunks; j++) {
1144                 bitmap_counter_t *bmc;
1145                 if (!bitmap->filemap) {
1146                         if (!log)
1147                                 /* error or shutdown */
1148                                 break;
1149                 } else
1150                         page = filemap_get_page(bitmap, j);
1151
1152                 if (page != lastpage) {
1153                         /* skip this page unless it's marked as needing cleaning */
1154                         if (!test_page_attr(bitmap, page, BITMAP_PAGE_CLEAN)) {
1155                                 int need_write = test_page_attr(bitmap, page,
1156                                                                 BITMAP_PAGE_NEEDWRITE);
1157                                 if (need_write)
1158                                         clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
1159
1160                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1161                                 if (need_write) {
1162                                         write_page(bitmap, page, 0);
1163                                         bitmap->allclean = 0;
1164                                 }
1165                                 spin_lock_irqsave(&bitmap->lock, flags);
1166                                 j |= (PAGE_BITS - 1);
1167                                 continue;
1168                         }
1169
1170                         /* grab the new page, sync and release the old */
1171                         if (lastpage != NULL) {
1172                                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1173                                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1174                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1175                                         write_page(bitmap, lastpage, 0);
1176                                 } else {
1177                                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1178                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1179                                 }
1180                         } else
1181                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1182                         lastpage = page;
1183
1184                         /* We are possibly going to clear some bits, so make
1185                          * sure that events_cleared is up-to-date.
1186                          */
1187                         if (bitmap->need_sync &&
1188                             bitmap->mddev->bitmap_info.external == 0) {
1189                                 bitmap_super_t *sb;
1190                                 bitmap->need_sync = 0;
1191                                 sb = kmap_atomic(bitmap->sb_page, KM_USER0);
1192                                 sb->events_cleared =
1193                                         cpu_to_le64(bitmap->events_cleared);
1194                                 kunmap_atomic(sb, KM_USER0);
1195                                 write_page(bitmap, bitmap->sb_page, 1);
1196                         }
1197                         spin_lock_irqsave(&bitmap->lock, flags);
1198                         if (!bitmap->need_sync)
1199                                 clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1200                 }
1201                 bmc = bitmap_get_counter(bitmap,
1202                                          (sector_t)j << CHUNK_BLOCK_SHIFT(bitmap),
1203                                          &blocks, 0);
1204                 if (bmc) {
1205                         if (*bmc)
1206                                 bitmap->allclean = 0;
1207
1208                         if (*bmc == 2) {
1209                                 *bmc = 1; /* maybe clear the bit next time */
1210                                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1211                         } else if (*bmc == 1 && !bitmap->need_sync) {
1212                                 /* we can clear the bit */
1213                                 *bmc = 0;
1214                                 bitmap_count_page(bitmap,
1215                                                   (sector_t)j << CHUNK_BLOCK_SHIFT(bitmap),
1216                                                   -1);
1217
1218                                 /* clear the bit */
1219                                 if (page) {
1220                                         paddr = kmap_atomic(page, KM_USER0);
1221                                         if (bitmap->flags & BITMAP_HOSTENDIAN)
1222                                                 clear_bit(file_page_offset(bitmap, j),
1223                                                           paddr);
1224                                         else
1225                                                 ext2_clear_bit(file_page_offset(bitmap, j),
1226                                                                paddr);
1227                                         kunmap_atomic(paddr, KM_USER0);
1228                                 } else
1229                                         log->type->clear_region(log, j);
1230                         }
1231                 } else
1232                         j |= PAGE_COUNTER_MASK;
1233         }
1234         spin_unlock_irqrestore(&bitmap->lock, flags);
1235
1236         /* now sync the final page */
1237         if (lastpage != NULL || log != NULL) {
1238                 spin_lock_irqsave(&bitmap->lock, flags);
1239                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1240                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1241                         spin_unlock_irqrestore(&bitmap->lock, flags);
1242                         if (lastpage)
1243                                 write_page(bitmap, lastpage, 0);
1244                         else
1245                                 if (log->type->flush(log))
1246                                         bitmap->flags |= BITMAP_WRITE_ERROR;
1247                 } else {
1248                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1249                         spin_unlock_irqrestore(&bitmap->lock, flags);
1250                 }
1251         }
1252
1253  done:
1254         if (bitmap->allclean == 0)
1255                 bitmap->mddev->thread->timeout =
1256                         bitmap->mddev->bitmap_info.daemon_sleep;
1257         mutex_unlock(&mddev->bitmap_info.mutex);
1258 }
1259
1260 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1261                                             sector_t offset, sector_t *blocks,
1262                                             int create)
1263 __releases(bitmap->lock)
1264 __acquires(bitmap->lock)
1265 {
1266         /* If 'create', we might release the lock and reclaim it.
1267          * The lock must have been taken with interrupts enabled.
1268          * If !create, we don't release the lock.
1269          */
1270         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1271         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1272         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1273         sector_t csize;
1274         int err;
1275
1276         err = bitmap_checkpage(bitmap, page, create);
1277
1278         if (bitmap->bp[page].hijacked ||
1279             bitmap->bp[page].map == NULL)
1280                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap) +
1281                                           PAGE_COUNTER_SHIFT - 1);
1282         else
1283                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1284         *blocks = csize - (offset & (csize - 1));
1285
1286         if (err < 0)
1287                 return NULL;
1288
1289         /* now locked ... */
1290
1291         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1292                 /* should we use the first or second counter field
1293                  * of the hijacked pointer? */
1294                 int hi = (pageoff > PAGE_COUNTER_MASK);
1295                 return  &((bitmap_counter_t *)
1296                           &bitmap->bp[page].map)[hi];
1297         } else /* page is allocated */
1298                 return (bitmap_counter_t *)
1299                         &(bitmap->bp[page].map[pageoff]);
1300 }
1301
1302 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1303 {
1304         if (!bitmap)
1305                 return 0;
1306
1307         if (behind) {
1308                 int bw;
1309                 atomic_inc(&bitmap->behind_writes);
1310                 bw = atomic_read(&bitmap->behind_writes);
1311                 if (bw > bitmap->behind_writes_used)
1312                         bitmap->behind_writes_used = bw;
1313
1314                 PRINTK(KERN_DEBUG "inc write-behind count %d/%d\n",
1315                        bw, bitmap->max_write_behind);
1316         }
1317
1318         while (sectors) {
1319                 sector_t blocks;
1320                 bitmap_counter_t *bmc;
1321
1322                 spin_lock_irq(&bitmap->lock);
1323                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 1);
1324                 if (!bmc) {
1325                         spin_unlock_irq(&bitmap->lock);
1326                         return 0;
1327                 }
1328
1329                 if (unlikely((*bmc & COUNTER_MAX) == COUNTER_MAX)) {
1330                         DEFINE_WAIT(__wait);
1331                         /* note that it is safe to do the prepare_to_wait
1332                          * after the test as long as we do it before dropping
1333                          * the spinlock.
1334                          */
1335                         prepare_to_wait(&bitmap->overflow_wait, &__wait,
1336                                         TASK_UNINTERRUPTIBLE);
1337                         spin_unlock_irq(&bitmap->lock);
1338                         md_unplug(bitmap->mddev);
1339                         schedule();
1340                         finish_wait(&bitmap->overflow_wait, &__wait);
1341                         continue;
1342                 }
1343
1344                 switch (*bmc) {
1345                 case 0:
1346                         bitmap_file_set_bit(bitmap, offset);
1347                         bitmap_count_page(bitmap, offset, 1);
1348                         /* fall through */
1349                 case 1:
1350                         *bmc = 2;
1351                 }
1352
1353                 (*bmc)++;
1354
1355                 spin_unlock_irq(&bitmap->lock);
1356
1357                 offset += blocks;
1358                 if (sectors > blocks)
1359                         sectors -= blocks;
1360                 else
1361                         sectors = 0;
1362         }
1363         bitmap->allclean = 0;
1364         return 0;
1365 }
1366 EXPORT_SYMBOL(bitmap_startwrite);
1367
1368 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1369                      int success, int behind)
1370 {
1371         if (!bitmap)
1372                 return;
1373         if (behind) {
1374                 if (atomic_dec_and_test(&bitmap->behind_writes))
1375                         wake_up(&bitmap->behind_wait);
1376                 PRINTK(KERN_DEBUG "dec write-behind count %d/%d\n",
1377                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1378         }
1379         if (bitmap->mddev->degraded)
1380                 /* Never clear bits or update events_cleared when degraded */
1381                 success = 0;
1382
1383         while (sectors) {
1384                 sector_t blocks;
1385                 unsigned long flags;
1386                 bitmap_counter_t *bmc;
1387
1388                 spin_lock_irqsave(&bitmap->lock, flags);
1389                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 0);
1390                 if (!bmc) {
1391                         spin_unlock_irqrestore(&bitmap->lock, flags);
1392                         return;
1393                 }
1394
1395                 if (success &&
1396                     bitmap->events_cleared < bitmap->mddev->events) {
1397                         bitmap->events_cleared = bitmap->mddev->events;
1398                         bitmap->need_sync = 1;
1399                         sysfs_notify_dirent_safe(bitmap->sysfs_can_clear);
1400                 }
1401
1402                 if (!success && ! (*bmc & NEEDED_MASK))
1403                         *bmc |= NEEDED_MASK;
1404
1405                 if ((*bmc & COUNTER_MAX) == COUNTER_MAX)
1406                         wake_up(&bitmap->overflow_wait);
1407
1408                 (*bmc)--;
1409                 if (*bmc <= 2)
1410                         set_page_attr(bitmap,
1411                                       filemap_get_page(
1412                                               bitmap,
1413                                               offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1414                                       BITMAP_PAGE_CLEAN);
1415
1416                 spin_unlock_irqrestore(&bitmap->lock, flags);
1417                 offset += blocks;
1418                 if (sectors > blocks)
1419                         sectors -= blocks;
1420                 else
1421                         sectors = 0;
1422         }
1423 }
1424 EXPORT_SYMBOL(bitmap_endwrite);
1425
1426 static int __bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1427                                int degraded)
1428 {
1429         bitmap_counter_t *bmc;
1430         int rv;
1431         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1432                 *blocks = 1024;
1433                 return 1; /* always resync if no bitmap */
1434         }
1435         spin_lock_irq(&bitmap->lock);
1436         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1437         rv = 0;
1438         if (bmc) {
1439                 /* locked */
1440                 if (RESYNC(*bmc))
1441                         rv = 1;
1442                 else if (NEEDED(*bmc)) {
1443                         rv = 1;
1444                         if (!degraded) { /* don't set/clear bits if degraded */
1445                                 *bmc |= RESYNC_MASK;
1446                                 *bmc &= ~NEEDED_MASK;
1447                         }
1448                 }
1449         }
1450         spin_unlock_irq(&bitmap->lock);
1451         bitmap->allclean = 0;
1452         return rv;
1453 }
1454
1455 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1456                       int degraded)
1457 {
1458         /* bitmap_start_sync must always report on multiples of whole
1459          * pages, otherwise resync (which is very PAGE_SIZE based) will
1460          * get confused.
1461          * So call __bitmap_start_sync repeatedly (if needed) until
1462          * At least PAGE_SIZE>>9 blocks are covered.
1463          * Return the 'or' of the result.
1464          */
1465         int rv = 0;
1466         sector_t blocks1;
1467
1468         *blocks = 0;
1469         while (*blocks < (PAGE_SIZE>>9)) {
1470                 rv |= __bitmap_start_sync(bitmap, offset,
1471                                           &blocks1, degraded);
1472                 offset += blocks1;
1473                 *blocks += blocks1;
1474         }
1475         return rv;
1476 }
1477 EXPORT_SYMBOL(bitmap_start_sync);
1478
1479 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks, int aborted)
1480 {
1481         bitmap_counter_t *bmc;
1482         unsigned long flags;
1483
1484         if (bitmap == NULL) {
1485                 *blocks = 1024;
1486                 return;
1487         }
1488         spin_lock_irqsave(&bitmap->lock, flags);
1489         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1490         if (bmc == NULL)
1491                 goto unlock;
1492         /* locked */
1493         if (RESYNC(*bmc)) {
1494                 *bmc &= ~RESYNC_MASK;
1495
1496                 if (!NEEDED(*bmc) && aborted)
1497                         *bmc |= NEEDED_MASK;
1498                 else {
1499                         if (*bmc <= 2)
1500                                 set_page_attr(bitmap,
1501                                               filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1502                                               BITMAP_PAGE_CLEAN);
1503                 }
1504         }
1505  unlock:
1506         spin_unlock_irqrestore(&bitmap->lock, flags);
1507         bitmap->allclean = 0;
1508 }
1509 EXPORT_SYMBOL(bitmap_end_sync);
1510
1511 void bitmap_close_sync(struct bitmap *bitmap)
1512 {
1513         /* Sync has finished, and any bitmap chunks that weren't synced
1514          * properly have been aborted.  It remains to us to clear the
1515          * RESYNC bit wherever it is still on
1516          */
1517         sector_t sector = 0;
1518         sector_t blocks;
1519         if (!bitmap)
1520                 return;
1521         while (sector < bitmap->mddev->resync_max_sectors) {
1522                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1523                 sector += blocks;
1524         }
1525 }
1526 EXPORT_SYMBOL(bitmap_close_sync);
1527
1528 void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector)
1529 {
1530         sector_t s = 0;
1531         sector_t blocks;
1532
1533         if (!bitmap)
1534                 return;
1535         if (sector == 0) {
1536                 bitmap->last_end_sync = jiffies;
1537                 return;
1538         }
1539         if (time_before(jiffies, (bitmap->last_end_sync
1540                                   + bitmap->mddev->bitmap_info.daemon_sleep)))
1541                 return;
1542         wait_event(bitmap->mddev->recovery_wait,
1543                    atomic_read(&bitmap->mddev->recovery_active) == 0);
1544
1545         bitmap->mddev->curr_resync_completed = bitmap->mddev->curr_resync;
1546         set_bit(MD_CHANGE_CLEAN, &bitmap->mddev->flags);
1547         sector &= ~((1ULL << CHUNK_BLOCK_SHIFT(bitmap)) - 1);
1548         s = 0;
1549         while (s < sector && s < bitmap->mddev->resync_max_sectors) {
1550                 bitmap_end_sync(bitmap, s, &blocks, 0);
1551                 s += blocks;
1552         }
1553         bitmap->last_end_sync = jiffies;
1554         sysfs_notify(&bitmap->mddev->kobj, NULL, "sync_completed");
1555 }
1556 EXPORT_SYMBOL(bitmap_cond_end_sync);
1557
1558 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1559 {
1560         /* For each chunk covered by any of these sectors, set the
1561          * counter to 1 and set resync_needed.  They should all
1562          * be 0 at this point
1563          */
1564
1565         sector_t secs;
1566         bitmap_counter_t *bmc;
1567         spin_lock_irq(&bitmap->lock);
1568         bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
1569         if (!bmc) {
1570                 spin_unlock_irq(&bitmap->lock);
1571                 return;
1572         }
1573         if (!*bmc) {
1574                 struct page *page;
1575                 *bmc = 1 | (needed ? NEEDED_MASK : 0);
1576                 bitmap_count_page(bitmap, offset, 1);
1577                 page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));
1578                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1579         }
1580         spin_unlock_irq(&bitmap->lock);
1581         bitmap->allclean = 0;
1582 }
1583
1584 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
1585 void bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1586 {
1587         unsigned long chunk;
1588
1589         for (chunk = s; chunk <= e; chunk++) {
1590                 sector_t sec = (sector_t)chunk << CHUNK_BLOCK_SHIFT(bitmap);
1591                 bitmap_set_memory_bits(bitmap, sec, 1);
1592                 bitmap_file_set_bit(bitmap, sec);
1593                 if (sec < bitmap->mddev->recovery_cp)
1594                         /* We are asserting that the array is dirty,
1595                          * so move the recovery_cp address back so
1596                          * that it is obvious that it is dirty
1597                          */
1598                         bitmap->mddev->recovery_cp = sec;
1599         }
1600 }
1601
1602 /*
1603  * flush out any pending updates
1604  */
1605 void bitmap_flush(mddev_t *mddev)
1606 {
1607         struct bitmap *bitmap = mddev->bitmap;
1608         long sleep;
1609
1610         if (!bitmap) /* there was no bitmap */
1611                 return;
1612
1613         /* run the daemon_work three time to ensure everything is flushed
1614          * that can be
1615          */
1616         sleep = mddev->bitmap_info.daemon_sleep * 2;
1617         bitmap->daemon_lastrun -= sleep;
1618         bitmap_daemon_work(mddev);
1619         bitmap->daemon_lastrun -= sleep;
1620         bitmap_daemon_work(mddev);
1621         bitmap->daemon_lastrun -= sleep;
1622         bitmap_daemon_work(mddev);
1623         bitmap_update_sb(bitmap);
1624 }
1625
1626 /*
1627  * free memory that was allocated
1628  */
1629 static void bitmap_free(struct bitmap *bitmap)
1630 {
1631         unsigned long k, pages;
1632         struct bitmap_page *bp;
1633
1634         if (!bitmap) /* there was no bitmap */
1635                 return;
1636
1637         /* release the bitmap file and kill the daemon */
1638         bitmap_file_put(bitmap);
1639
1640         bp = bitmap->bp;
1641         pages = bitmap->pages;
1642
1643         /* free all allocated memory */
1644
1645         if (bp) /* deallocate the page memory */
1646                 for (k = 0; k < pages; k++)
1647                         if (bp[k].map && !bp[k].hijacked)
1648                                 kfree(bp[k].map);
1649         kfree(bp);
1650         kfree(bitmap);
1651 }
1652
1653 void bitmap_destroy(mddev_t *mddev)
1654 {
1655         struct bitmap *bitmap = mddev->bitmap;
1656
1657         if (!bitmap) /* there was no bitmap */
1658                 return;
1659
1660         mutex_lock(&mddev->bitmap_info.mutex);
1661         mddev->bitmap = NULL; /* disconnect from the md device */
1662         mutex_unlock(&mddev->bitmap_info.mutex);
1663         if (mddev->thread)
1664                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1665
1666         if (bitmap->sysfs_can_clear)
1667                 sysfs_put(bitmap->sysfs_can_clear);
1668
1669         bitmap_free(bitmap);
1670 }
1671
1672 /*
1673  * initialize the bitmap structure
1674  * if this returns an error, bitmap_destroy must be called to do clean up
1675  */
1676 int bitmap_create(mddev_t *mddev)
1677 {
1678         struct bitmap *bitmap;
1679         sector_t blocks = mddev->resync_max_sectors;
1680         unsigned long chunks;
1681         unsigned long pages;
1682         struct file *file = mddev->bitmap_info.file;
1683         int err;
1684         struct sysfs_dirent *bm = NULL;
1685
1686         BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
1687
1688         if (!file
1689             && !mddev->bitmap_info.offset
1690             && !mddev->bitmap_info.log) /* bitmap disabled, nothing to do */
1691                 return 0;
1692
1693         BUG_ON(file && mddev->bitmap_info.offset);
1694         BUG_ON(mddev->bitmap_info.offset && mddev->bitmap_info.log);
1695
1696         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1697         if (!bitmap)
1698                 return -ENOMEM;
1699
1700         spin_lock_init(&bitmap->lock);
1701         atomic_set(&bitmap->pending_writes, 0);
1702         init_waitqueue_head(&bitmap->write_wait);
1703         init_waitqueue_head(&bitmap->overflow_wait);
1704         init_waitqueue_head(&bitmap->behind_wait);
1705
1706         bitmap->mddev = mddev;
1707
1708         if (mddev->kobj.sd)
1709                 bm = sysfs_get_dirent(mddev->kobj.sd, NULL, "bitmap");
1710         if (bm) {
1711                 bitmap->sysfs_can_clear = sysfs_get_dirent(bm, NULL, "can_clear");
1712                 sysfs_put(bm);
1713         } else
1714                 bitmap->sysfs_can_clear = NULL;
1715
1716         bitmap->file = file;
1717         if (file) {
1718                 get_file(file);
1719                 /* As future accesses to this file will use bmap,
1720                  * and bypass the page cache, we must sync the file
1721                  * first.
1722                  */
1723                 vfs_fsync(file, 1);
1724         }
1725         /* read superblock from bitmap file (this sets mddev->bitmap_info.chunksize) */
1726         if (!mddev->bitmap_info.external)
1727                 err = bitmap_read_sb(bitmap);
1728         else {
1729                 err = 0;
1730                 if (mddev->bitmap_info.chunksize == 0 ||
1731                     mddev->bitmap_info.daemon_sleep == 0)
1732                         /* chunksize and time_base need to be
1733                          * set first. */
1734                         err = -EINVAL;
1735         }
1736         if (err)
1737                 goto error;
1738
1739         bitmap->daemon_lastrun = jiffies;
1740         bitmap->chunkshift = ffz(~mddev->bitmap_info.chunksize);
1741
1742         /* now that chunksize and chunkshift are set, we can use these macros */
1743         chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) >>
1744                         CHUNK_BLOCK_SHIFT(bitmap);
1745         pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
1746
1747         BUG_ON(!pages);
1748
1749         bitmap->chunks = chunks;
1750         bitmap->pages = pages;
1751         bitmap->missing_pages = pages;
1752         bitmap->counter_bits = COUNTER_BITS;
1753
1754         bitmap->syncchunk = ~0UL;
1755
1756 #ifdef INJECT_FATAL_FAULT_1
1757         bitmap->bp = NULL;
1758 #else
1759         bitmap->bp = kzalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
1760 #endif
1761         err = -ENOMEM;
1762         if (!bitmap->bp)
1763                 goto error;
1764
1765         printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
1766                 pages, bmname(bitmap));
1767
1768         mddev->bitmap = bitmap;
1769
1770
1771         return (bitmap->flags & BITMAP_WRITE_ERROR) ? -EIO : 0;
1772
1773  error:
1774         bitmap_free(bitmap);
1775         return err;
1776 }
1777
1778 int bitmap_load(mddev_t *mddev)
1779 {
1780         int err = 0;
1781         sector_t sector = 0;
1782         struct bitmap *bitmap = mddev->bitmap;
1783
1784         if (!bitmap)
1785                 goto out;
1786
1787         /* Clear out old bitmap info first:  Either there is none, or we
1788          * are resuming after someone else has possibly changed things,
1789          * so we should forget old cached info.
1790          * All chunks should be clean, but some might need_sync.
1791          */
1792         while (sector < mddev->resync_max_sectors) {
1793                 sector_t blocks;
1794                 bitmap_start_sync(bitmap, sector, &blocks, 0);
1795                 sector += blocks;
1796         }
1797         bitmap_close_sync(bitmap);
1798
1799         if (mddev->bitmap_info.log) {
1800                 unsigned long i;
1801                 struct dm_dirty_log *log = mddev->bitmap_info.log;
1802                 for (i = 0; i < bitmap->chunks; i++)
1803                         if (!log->type->in_sync(log, i, 1))
1804                                 bitmap_set_memory_bits(bitmap,
1805                                                        (sector_t)i << CHUNK_BLOCK_SHIFT(bitmap),
1806                                                        1);
1807         } else {
1808                 sector_t start = 0;
1809                 if (mddev->degraded == 0
1810                     || bitmap->events_cleared == mddev->events)
1811                         /* no need to keep dirty bits to optimise a
1812                          * re-add of a missing device */
1813                         start = mddev->recovery_cp;
1814
1815                 err = bitmap_init_from_disk(bitmap, start);
1816         }
1817         if (err)
1818                 goto out;
1819
1820         mddev->thread->timeout = mddev->bitmap_info.daemon_sleep;
1821         md_wakeup_thread(mddev->thread);
1822
1823         bitmap_update_sb(bitmap);
1824
1825         if (bitmap->flags & BITMAP_WRITE_ERROR)
1826                 err = -EIO;
1827 out:
1828         return err;
1829 }
1830 EXPORT_SYMBOL_GPL(bitmap_load);
1831
1832 static ssize_t
1833 location_show(mddev_t *mddev, char *page)
1834 {
1835         ssize_t len;
1836         if (mddev->bitmap_info.file)
1837                 len = sprintf(page, "file");
1838         else if (mddev->bitmap_info.offset)
1839                 len = sprintf(page, "%+lld", (long long)mddev->bitmap_info.offset);
1840         else
1841                 len = sprintf(page, "none");
1842         len += sprintf(page+len, "\n");
1843         return len;
1844 }
1845
1846 static ssize_t
1847 location_store(mddev_t *mddev, const char *buf, size_t len)
1848 {
1849
1850         if (mddev->pers) {
1851                 if (!mddev->pers->quiesce)
1852                         return -EBUSY;
1853                 if (mddev->recovery || mddev->sync_thread)
1854                         return -EBUSY;
1855         }
1856
1857         if (mddev->bitmap || mddev->bitmap_info.file ||
1858             mddev->bitmap_info.offset) {
1859                 /* bitmap already configured.  Only option is to clear it */
1860                 if (strncmp(buf, "none", 4) != 0)
1861                         return -EBUSY;
1862                 if (mddev->pers) {
1863                         mddev->pers->quiesce(mddev, 1);
1864                         bitmap_destroy(mddev);
1865                         mddev->pers->quiesce(mddev, 0);
1866                 }
1867                 mddev->bitmap_info.offset = 0;
1868                 if (mddev->bitmap_info.file) {
1869                         struct file *f = mddev->bitmap_info.file;
1870                         mddev->bitmap_info.file = NULL;
1871                         restore_bitmap_write_access(f);
1872                         fput(f);
1873                 }
1874         } else {
1875                 /* No bitmap, OK to set a location */
1876                 long long offset;
1877                 if (strncmp(buf, "none", 4) == 0)
1878                         /* nothing to be done */;
1879                 else if (strncmp(buf, "file:", 5) == 0) {
1880                         /* Not supported yet */
1881                         return -EINVAL;
1882                 } else {
1883                         int rv;
1884                         if (buf[0] == '+')
1885                                 rv = strict_strtoll(buf+1, 10, &offset);
1886                         else
1887                                 rv = strict_strtoll(buf, 10, &offset);
1888                         if (rv)
1889                                 return rv;
1890                         if (offset == 0)
1891                                 return -EINVAL;
1892                         if (mddev->bitmap_info.external == 0 &&
1893                             mddev->major_version == 0 &&
1894                             offset != mddev->bitmap_info.default_offset)
1895                                 return -EINVAL;
1896                         mddev->bitmap_info.offset = offset;
1897                         if (mddev->pers) {
1898                                 mddev->pers->quiesce(mddev, 1);
1899                                 rv = bitmap_create(mddev);
1900                                 if (rv) {
1901                                         bitmap_destroy(mddev);
1902                                         mddev->bitmap_info.offset = 0;
1903                                 }
1904                                 mddev->pers->quiesce(mddev, 0);
1905                                 if (rv)
1906                                         return rv;
1907                         }
1908                 }
1909         }
1910         if (!mddev->external) {
1911                 /* Ensure new bitmap info is stored in
1912                  * metadata promptly.
1913                  */
1914                 set_bit(MD_CHANGE_DEVS, &mddev->flags);
1915                 md_wakeup_thread(mddev->thread);
1916         }
1917         return len;
1918 }
1919
1920 static struct md_sysfs_entry bitmap_location =
1921 __ATTR(location, S_IRUGO|S_IWUSR, location_show, location_store);
1922
1923 static ssize_t
1924 timeout_show(mddev_t *mddev, char *page)
1925 {
1926         ssize_t len;
1927         unsigned long secs = mddev->bitmap_info.daemon_sleep / HZ;
1928         unsigned long jifs = mddev->bitmap_info.daemon_sleep % HZ;
1929
1930         len = sprintf(page, "%lu", secs);
1931         if (jifs)
1932                 len += sprintf(page+len, ".%03u", jiffies_to_msecs(jifs));
1933         len += sprintf(page+len, "\n");
1934         return len;
1935 }
1936
1937 static ssize_t
1938 timeout_store(mddev_t *mddev, const char *buf, size_t len)
1939 {
1940         /* timeout can be set at any time */
1941         unsigned long timeout;
1942         int rv = strict_strtoul_scaled(buf, &timeout, 4);
1943         if (rv)
1944                 return rv;
1945
1946         /* just to make sure we don't overflow... */
1947         if (timeout >= LONG_MAX / HZ)
1948                 return -EINVAL;
1949
1950         timeout = timeout * HZ / 10000;
1951
1952         if (timeout >= MAX_SCHEDULE_TIMEOUT)
1953                 timeout = MAX_SCHEDULE_TIMEOUT-1;
1954         if (timeout < 1)
1955                 timeout = 1;
1956         mddev->bitmap_info.daemon_sleep = timeout;
1957         if (mddev->thread) {
1958                 /* if thread->timeout is MAX_SCHEDULE_TIMEOUT, then
1959                  * the bitmap is all clean and we don't need to
1960                  * adjust the timeout right now
1961                  */
1962                 if (mddev->thread->timeout < MAX_SCHEDULE_TIMEOUT) {
1963                         mddev->thread->timeout = timeout;
1964                         md_wakeup_thread(mddev->thread);
1965                 }
1966         }
1967         return len;
1968 }
1969
1970 static struct md_sysfs_entry bitmap_timeout =
1971 __ATTR(time_base, S_IRUGO|S_IWUSR, timeout_show, timeout_store);
1972
1973 static ssize_t
1974 backlog_show(mddev_t *mddev, char *page)
1975 {
1976         return sprintf(page, "%lu\n", mddev->bitmap_info.max_write_behind);
1977 }
1978
1979 static ssize_t
1980 backlog_store(mddev_t *mddev, const char *buf, size_t len)
1981 {
1982         unsigned long backlog;
1983         int rv = strict_strtoul(buf, 10, &backlog);
1984         if (rv)
1985                 return rv;
1986         if (backlog > COUNTER_MAX)
1987                 return -EINVAL;
1988         mddev->bitmap_info.max_write_behind = backlog;
1989         return len;
1990 }
1991
1992 static struct md_sysfs_entry bitmap_backlog =
1993 __ATTR(backlog, S_IRUGO|S_IWUSR, backlog_show, backlog_store);
1994
1995 static ssize_t
1996 chunksize_show(mddev_t *mddev, char *page)
1997 {
1998         return sprintf(page, "%lu\n", mddev->bitmap_info.chunksize);
1999 }
2000
2001 static ssize_t
2002 chunksize_store(mddev_t *mddev, const char *buf, size_t len)
2003 {
2004         /* Can only be changed when no bitmap is active */
2005         int rv;
2006         unsigned long csize;
2007         if (mddev->bitmap)
2008                 return -EBUSY;
2009         rv = strict_strtoul(buf, 10, &csize);
2010         if (rv)
2011                 return rv;
2012         if (csize < 512 ||
2013             !is_power_of_2(csize))
2014                 return -EINVAL;
2015         mddev->bitmap_info.chunksize = csize;
2016         return len;
2017 }
2018
2019 static struct md_sysfs_entry bitmap_chunksize =
2020 __ATTR(chunksize, S_IRUGO|S_IWUSR, chunksize_show, chunksize_store);
2021
2022 static ssize_t metadata_show(mddev_t *mddev, char *page)
2023 {
2024         return sprintf(page, "%s\n", (mddev->bitmap_info.external
2025                                       ? "external" : "internal"));
2026 }
2027
2028 static ssize_t metadata_store(mddev_t *mddev, const char *buf, size_t len)
2029 {
2030         if (mddev->bitmap ||
2031             mddev->bitmap_info.file ||
2032             mddev->bitmap_info.offset)
2033                 return -EBUSY;
2034         if (strncmp(buf, "external", 8) == 0)
2035                 mddev->bitmap_info.external = 1;
2036         else if (strncmp(buf, "internal", 8) == 0)
2037                 mddev->bitmap_info.external = 0;
2038         else
2039                 return -EINVAL;
2040         return len;
2041 }
2042
2043 static struct md_sysfs_entry bitmap_metadata =
2044 __ATTR(metadata, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
2045
2046 static ssize_t can_clear_show(mddev_t *mddev, char *page)
2047 {
2048         int len;
2049         if (mddev->bitmap)
2050                 len = sprintf(page, "%s\n", (mddev->bitmap->need_sync ?
2051                                              "false" : "true"));
2052         else
2053                 len = sprintf(page, "\n");
2054         return len;
2055 }
2056
2057 static ssize_t can_clear_store(mddev_t *mddev, const char *buf, size_t len)
2058 {
2059         if (mddev->bitmap == NULL)
2060                 return -ENOENT;
2061         if (strncmp(buf, "false", 5) == 0)
2062                 mddev->bitmap->need_sync = 1;
2063         else if (strncmp(buf, "true", 4) == 0) {
2064                 if (mddev->degraded)
2065                         return -EBUSY;
2066                 mddev->bitmap->need_sync = 0;
2067         } else
2068                 return -EINVAL;
2069         return len;
2070 }
2071
2072 static struct md_sysfs_entry bitmap_can_clear =
2073 __ATTR(can_clear, S_IRUGO|S_IWUSR, can_clear_show, can_clear_store);
2074
2075 static ssize_t
2076 behind_writes_used_show(mddev_t *mddev, char *page)
2077 {
2078         if (mddev->bitmap == NULL)
2079                 return sprintf(page, "0\n");
2080         return sprintf(page, "%lu\n",
2081                        mddev->bitmap->behind_writes_used);
2082 }
2083
2084 static ssize_t
2085 behind_writes_used_reset(mddev_t *mddev, const char *buf, size_t len)
2086 {
2087         if (mddev->bitmap)
2088                 mddev->bitmap->behind_writes_used = 0;
2089         return len;
2090 }
2091
2092 static struct md_sysfs_entry max_backlog_used =
2093 __ATTR(max_backlog_used, S_IRUGO | S_IWUSR,
2094        behind_writes_used_show, behind_writes_used_reset);
2095
2096 static struct attribute *md_bitmap_attrs[] = {
2097         &bitmap_location.attr,
2098         &bitmap_timeout.attr,
2099         &bitmap_backlog.attr,
2100         &bitmap_chunksize.attr,
2101         &bitmap_metadata.attr,
2102         &bitmap_can_clear.attr,
2103         &max_backlog_used.attr,
2104         NULL
2105 };
2106 struct attribute_group md_bitmap_group = {
2107         .name = "bitmap",
2108         .attrs = md_bitmap_attrs,
2109 };
2110