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 <linux/seq_file.h>
  30 #include "md.h"
  31 #include "bitmap.h"
  32
  33 static inline char *bmname(struct bitmap *bitmap)
  34 {
  35         return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
  36 }
  37
  38 /*
  39  * check a page and, if necessary, allocate it (or hijack it if the alloc fails)
  40  *
  41  * 1) check to see if this page is allocated, if it's not then try to alloc
  42  * 2) if the alloc fails, set the page's hijacked flag so we'll use the
  43  *    page pointer directly as a counter
  44  *
  45  * if we find our page, we increment the page's refcount so that it stays
  46  * allocated while we're using it
  47  */
  48 static int bitmap_checkpage(struct bitmap_counts *bitmap,
  49                             unsigned long page, int create)
  50 __releases(bitmap->lock)
  51 __acquires(bitmap->lock)
  52 {
  53         unsigned char *mappage;
  54
  55         if (page >= bitmap->pages) {
  56                 /* This can happen if bitmap_start_sync goes beyond
  57                  * End-of-device while looking for a whole page.
  58                  * It is harmless.
  59                  */
  60                 return -EINVAL;
  61         }
  62
  63         if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
  64                 return 0;
  65
  66         if (bitmap->bp[page].map) /* page is already allocated, just return */
  67                 return 0;
  68
  69         if (!create)
  70                 return -ENOENT;
  71
  72         /* this page has not been allocated yet */
  73
  74         spin_unlock_irq(&bitmap->lock);
  75         mappage = kzalloc(PAGE_SIZE, GFP_NOIO);
  76         spin_lock_irq(&bitmap->lock);
  77
  78         if (mappage == NULL) {
  79                 pr_debug("md/bitmap: map page allocation failed, hijacking\n");
  80                 /* failed - set the hijacked flag so that we can use the
  81                  * pointer as a counter */
  82                 if (!bitmap->bp[page].map)
  83                         bitmap->bp[page].hijacked = 1;
  84         } else if (bitmap->bp[page].map ||
  85                    bitmap->bp[page].hijacked) {
  86                 /* somebody beat us to getting the page */
  87                 kfree(mappage);
  88                 return 0;
  89         } else {
  90
  91                 /* no page was in place and we have one, so install it */
  92
  93                 bitmap->bp[page].map = mappage;
  94                 bitmap->missing_pages--;
  95         }
  96         return 0;
  97 }
  98
  99 /* if page is completely empty, put it back on the free list, or dealloc it */
 100 /* if page was hijacked, unmark the flag so it might get alloced next time */
 101 /* Note: lock should be held when calling this */
 102 static void bitmap_checkfree(struct bitmap_counts *bitmap, unsigned long page)
 103 {
 104         char *ptr;
 105
 106         if (bitmap->bp[page].count) /* page is still busy */
 107                 return;
 108
 109         /* page is no longer in use, it can be released */
 110
 111         if (bitmap->bp[page].hijacked) { /* page was hijacked, undo this now */
 112                 bitmap->bp[page].hijacked = 0;
 113                 bitmap->bp[page].map = NULL;
 114         } else {
 115                 /* normal case, free the page */
 116                 ptr = bitmap->bp[page].map;
 117                 bitmap->bp[page].map = NULL;
 118                 bitmap->missing_pages++;
 119                 kfree(ptr);
 120         }
 121 }
 122
 123 /*
 124  * bitmap file handling - read and write the bitmap file and its superblock
 125  */
 126
 127 /*
 128  * basic page I/O operations
 129  */
 130
 131 /* IO operations when bitmap is stored near all superblocks */
 132 static int read_sb_page(struct mddev *mddev, loff_t offset,
 133                         struct page *page,
 134                         unsigned long index, int size)
 135 {
 136         /* choose a good rdev and read the page from there */
 137
 138         struct md_rdev *rdev;
 139         sector_t target;
 140
 141         rdev_for_each(rdev, mddev) {
 142                 if (! test_bit(In_sync, &rdev->flags)
 143                     || test_bit(Faulty, &rdev->flags))
 144                         continue;
 145
 146                 target = offset + index * (PAGE_SIZE/512);
 147
 148                 if (sync_page_io(rdev, target,
 149                                  roundup(size, bdev_logical_block_size(rdev->bdev)),
 150                                  page, READ, true)) {
 151                         page->index = index;
 152                         return 0;
 153                 }
 154         }
 155         return -EIO;
 156 }
 157
 158 static struct md_rdev *next_active_rdev(struct md_rdev *rdev, struct mddev *mddev)
 159 {
 160         /* Iterate the disks of an mddev, using rcu to protect access to the
 161          * linked list, and raising the refcount of devices we return to ensure
 162          * they don't disappear while in use.
 163          * As devices are only added or removed when raid_disk is < 0 and
 164          * nr_pending is 0 and In_sync is clear, the entries we return will
 165          * still be in the same position on the list when we re-enter
 166          * list_for_each_entry_continue_rcu.
 167          */
 168         rcu_read_lock();
 169         if (rdev == NULL)
 170                 /* start at the beginning */
 171                 rdev = list_entry_rcu(&mddev->disks, struct md_rdev, same_set);
 172         else {
 173                 /* release the previous rdev and start from there. */
 174                 rdev_dec_pending(rdev, mddev);
 175         }
 176         list_for_each_entry_continue_rcu(rdev, &mddev->disks, same_set) {
 177                 if (rdev->raid_disk >= 0 &&
 178                     !test_bit(Faulty, &rdev->flags)) {
 179                         /* this is a usable devices */
 180                         atomic_inc(&rdev->nr_pending);
 181                         rcu_read_unlock();
 182                         return rdev;
 183                 }
 184         }
 185         rcu_read_unlock();
 186         return NULL;
 187 }
 188
 189 static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
 190 {
 191         struct md_rdev *rdev = NULL;
 192         struct block_device *bdev;
 193         struct mddev *mddev = bitmap->mddev;
 194         struct bitmap_storage *store = &bitmap->storage;
 195
 196         while ((rdev = next_active_rdev(rdev, mddev)) != NULL) {
 197                 int size = PAGE_SIZE;
 198                 loff_t offset = mddev->bitmap_info.offset;
 199
 200                 bdev = (rdev->meta_bdev) ? rdev->meta_bdev : rdev->bdev;
 201
 202                 if (page->index == store->file_pages-1) {
 203                         int last_page_size = store->bytes & (PAGE_SIZE-1);
 204                         if (last_page_size == 0)
 205                                 last_page_size = PAGE_SIZE;
 206                         size = roundup(last_page_size,
 207                                        bdev_logical_block_size(bdev));
 208                 }
 209                 /* Just make sure we aren't corrupting data or
 210                  * metadata
 211                  */
 212                 if (mddev->external) {
 213                         /* Bitmap could be anywhere. */
 214                         if (rdev->sb_start + offset + (page->index
 215                                                        * (PAGE_SIZE/512))
 216                             > rdev->data_offset
 217                             &&
 218                             rdev->sb_start + offset
 219                             < (rdev->data_offset + mddev->dev_sectors
 220                              + (PAGE_SIZE/512)))
 221                                 goto bad_alignment;
 222                 } else if (offset < 0) {
 223                         /* DATA  BITMAP METADATA  */
 224                         if (offset
 225                             + (long)(page->index * (PAGE_SIZE/512))
 226                             + size/512 > 0)
 227                                 /* bitmap runs in to metadata */
 228                                 goto bad_alignment;
 229                         if (rdev->data_offset + mddev->dev_sectors
 230                             > rdev->sb_start + offset)
 231                                 /* data runs in to bitmap */
 232                                 goto bad_alignment;
 233                 } else if (rdev->sb_start < rdev->data_offset) {
 234                         /* METADATA BITMAP DATA */
 235                         if (rdev->sb_start
 236                             + offset
 237                             + page->index*(PAGE_SIZE/512) + size/512
 238                             > rdev->data_offset)
 239                                 /* bitmap runs in to data */
 240                                 goto bad_alignment;
 241                 } else {
 242                         /* DATA METADATA BITMAP - no problems */
 243                 }
 244                 md_super_write(mddev, rdev,
 245                                rdev->sb_start + offset
 246                                + page->index * (PAGE_SIZE/512),
 247                                size,
 248                                page);
 249         }
 250
 251         if (wait)
 252                 md_super_wait(mddev);
 253         return 0;
 254
 255  bad_alignment:
 256         return -EINVAL;
 257 }
 258
 259 static void bitmap_file_kick(struct bitmap *bitmap);
 260 /*
 261  * write out a page to a file
 262  */
 263 static void write_page(struct bitmap *bitmap, struct page *page, int wait)
 264 {
 265         struct buffer_head *bh;
 266
 267         if (bitmap->storage.file == NULL) {
 268                 switch (write_sb_page(bitmap, page, wait)) {
 269                 case -EINVAL:
 270                         set_bit(BITMAP_WRITE_ERROR, &bitmap->flags);
 271                 }
 272         } else {
 273
 274                 bh = page_buffers(page);
 275
 276                 while (bh && bh->b_blocknr) {
 277                         atomic_inc(&bitmap->pending_writes);
 278                         set_buffer_locked(bh);
 279                         set_buffer_mapped(bh);
 280                         submit_bh(WRITE | REQ_SYNC, bh);
 281                         bh = bh->b_this_page;
 282                 }
 283
 284                 if (wait)
 285                         wait_event(bitmap->write_wait,
 286                                    atomic_read(&bitmap->pending_writes)==0);
 287         }
 288         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
 289                 bitmap_file_kick(bitmap);
 290 }
 291
 292 static void end_bitmap_write(struct buffer_head *bh, int uptodate)
 293 {
 294         struct bitmap *bitmap = bh->b_private;
 295
 296         if (!uptodate)
 297                 set_bit(BITMAP_WRITE_ERROR, &bitmap->flags);
 298         if (atomic_dec_and_test(&bitmap->pending_writes))
 299                 wake_up(&bitmap->write_wait);
 300 }
 301
 302 /* copied from buffer.c */
 303 static void
 304 __clear_page_buffers(struct page *page)
 305 {
 306         ClearPagePrivate(page);
 307         set_page_private(page, 0);
 308         page_cache_release(page);
 309 }
 310 static void free_buffers(struct page *page)
 311 {
 312         struct buffer_head *bh;
 313
 314         if (!PagePrivate(page))
 315                 return;
 316
 317         bh = page_buffers(page);
 318         while (bh) {
 319                 struct buffer_head *next = bh->b_this_page;
 320                 free_buffer_head(bh);
 321                 bh = next;
 322         }
 323         __clear_page_buffers(page);
 324         put_page(page);
 325 }
 326
 327 /* read a page from a file.
 328  * We both read the page, and attach buffers to the page to record the
 329  * address of each block (using bmap).  These addresses will be used
 330  * to write the block later, completely bypassing the filesystem.
 331  * This usage is similar to how swap files are handled, and allows us
 332  * to write to a file with no concerns of memory allocation failing.
 333  */
 334 static int read_page(struct file *file, unsigned long index,
 335                      struct bitmap *bitmap,
 336                      unsigned long count,
 337                      struct page *page)
 338 {
 339         int ret = 0;
 340         struct inode *inode = file_inode(file);
 341         struct buffer_head *bh;
 342         sector_t block;
 343
 344         pr_debug("read bitmap file (%dB @ %llu)\n", (int)PAGE_SIZE,
 345                  (unsigned long long)index << PAGE_SHIFT);
 346
 347         bh = alloc_page_buffers(page, 1<<inode->i_blkbits, 0);
 348         if (!bh) {
 349                 ret = -ENOMEM;
 350                 goto out;
 351         }
 352         attach_page_buffers(page, bh);
 353         block = index << (PAGE_SHIFT - inode->i_blkbits);
 354         while (bh) {
 355                 if (count == 0)
 356                         bh->b_blocknr = 0;
 357                 else {
 358                         bh->b_blocknr = bmap(inode, block);
 359                         if (bh->b_blocknr == 0) {
 360                                 /* Cannot use this file! */
 361                                 ret = -EINVAL;
 362                                 goto out;
 363                         }
 364                         bh->b_bdev = inode->i_sb->s_bdev;
 365                         if (count < (1<<inode->i_blkbits))
 366                                 count = 0;
 367                         else
 368                                 count -= (1<<inode->i_blkbits);
 369
 370                         bh->b_end_io = end_bitmap_write;
 371                         bh->b_private = bitmap;
 372                         atomic_inc(&bitmap->pending_writes);
 373                         set_buffer_locked(bh);
 374                         set_buffer_mapped(bh);
 375                         submit_bh(READ, bh);
 376                 }
 377                 block++;
 378                 bh = bh->b_this_page;
 379         }
 380         page->index = index;
 381
 382         wait_event(bitmap->write_wait,
 383                    atomic_read(&bitmap->pending_writes)==0);
 384         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
 385                 ret = -EIO;
 386 out:
 387         if (ret)
 388                 printk(KERN_ALERT "md: bitmap read error: (%dB @ %llu): %d\n",
 389                         (int)PAGE_SIZE,
 390                         (unsigned long long)index << PAGE_SHIFT,
 391                         ret);
 392         return ret;
 393 }
 394
 395 /*
 396  * bitmap file superblock operations
 397  */
 398
 399 /* update the event counter and sync the superblock to disk */
 400 void bitmap_update_sb(struct bitmap *bitmap)
 401 {
 402         bitmap_super_t *sb;
 403
 404         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
 405                 return;
 406         if (bitmap->mddev->bitmap_info.external)
 407                 return;
 408         if (!bitmap->storage.sb_page) /* no superblock */
 409                 return;
 410         sb = kmap_atomic(bitmap->storage.sb_page);
 411         sb->events = cpu_to_le64(bitmap->mddev->events);
 412         if (bitmap->mddev->events < bitmap->events_cleared)
 413                 /* rocking back to read-only */
 414                 bitmap->events_cleared = bitmap->mddev->events;
 415         sb->events_cleared = cpu_to_le64(bitmap->events_cleared);
 416         sb->state = cpu_to_le32(bitmap->flags);
 417         /* Just in case these have been changed via sysfs: */
 418         sb->daemon_sleep = cpu_to_le32(bitmap->mddev->bitmap_info.daemon_sleep/HZ);
 419         sb->write_behind = cpu_to_le32(bitmap->mddev->bitmap_info.max_write_behind);
 420         /* This might have been changed by a reshape */
 421         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 422         sb->chunksize = cpu_to_le32(bitmap->mddev->bitmap_info.chunksize);
 423         sb->sectors_reserved = cpu_to_le32(bitmap->mddev->
 424                                            bitmap_info.space);
 425         kunmap_atomic(sb);
 426         write_page(bitmap, bitmap->storage.sb_page, 1);
 427 }
 428
 429 /* print out the bitmap file superblock */
 430 void bitmap_print_sb(struct bitmap *bitmap)
 431 {
 432         bitmap_super_t *sb;
 433
 434         if (!bitmap || !bitmap->storage.sb_page)
 435                 return;
 436         sb = kmap_atomic(bitmap->storage.sb_page);
 437         printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
 438         printk(KERN_DEBUG "         magic: %08x\n", le32_to_cpu(sb->magic));
 439         printk(KERN_DEBUG "       version: %d\n", le32_to_cpu(sb->version));
 440         printk(KERN_DEBUG "          uuid: %08x.%08x.%08x.%08x\n",
 441                                         *(__u32 *)(sb->uuid+0),
 442                                         *(__u32 *)(sb->uuid+4),
 443                                         *(__u32 *)(sb->uuid+8),
 444                                         *(__u32 *)(sb->uuid+12));
 445         printk(KERN_DEBUG "        events: %llu\n",
 446                         (unsigned long long) le64_to_cpu(sb->events));
 447         printk(KERN_DEBUG "events cleared: %llu\n",
 448                         (unsigned long long) le64_to_cpu(sb->events_cleared));
 449         printk(KERN_DEBUG "         state: %08x\n", le32_to_cpu(sb->state));
 450         printk(KERN_DEBUG "     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
 451         printk(KERN_DEBUG "  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
 452         printk(KERN_DEBUG "     sync size: %llu KB\n",
 453                         (unsigned long long)le64_to_cpu(sb->sync_size)/2);
 454         printk(KERN_DEBUG "max write behind: %d\n", le32_to_cpu(sb->write_behind));
 455         kunmap_atomic(sb);
 456 }
 457
 458 /*
 459  * bitmap_new_disk_sb
 460  * @bitmap
 461  *
 462  * This function is somewhat the reverse of bitmap_read_sb.  bitmap_read_sb
 463  * reads and verifies the on-disk bitmap superblock and populates bitmap_info.
 464  * This function verifies 'bitmap_info' and populates the on-disk bitmap
 465  * structure, which is to be written to disk.
 466  *
 467  * Returns: 0 on success, -Exxx on error
 468  */
 469 static int bitmap_new_disk_sb(struct bitmap *bitmap)
 470 {
 471         bitmap_super_t *sb;
 472         unsigned long chunksize, daemon_sleep, write_behind;
 473
 474         bitmap->storage.sb_page = alloc_page(GFP_KERNEL);
 475         if (bitmap->storage.sb_page == NULL)
 476                 return -ENOMEM;
 477         bitmap->storage.sb_page->index = 0;
 478
 479         sb = kmap_atomic(bitmap->storage.sb_page);
 480
 481         sb->magic = cpu_to_le32(BITMAP_MAGIC);
 482         sb->version = cpu_to_le32(BITMAP_MAJOR_HI);
 483
 484         chunksize = bitmap->mddev->bitmap_info.chunksize;
 485         BUG_ON(!chunksize);
 486         if (!is_power_of_2(chunksize)) {
 487                 kunmap_atomic(sb);
 488                 printk(KERN_ERR "bitmap chunksize not a power of 2\n");
 489                 return -EINVAL;
 490         }
 491         sb->chunksize = cpu_to_le32(chunksize);
 492
 493         daemon_sleep = bitmap->mddev->bitmap_info.daemon_sleep;
 494         if (!daemon_sleep ||
 495             (daemon_sleep < 1) || (daemon_sleep > MAX_SCHEDULE_TIMEOUT)) {
 496                 printk(KERN_INFO "Choosing daemon_sleep default (5 sec)\n");
 497                 daemon_sleep = 5 * HZ;
 498         }
 499         sb->daemon_sleep = cpu_to_le32(daemon_sleep);
 500         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 501
 502         /*
 503          * FIXME: write_behind for RAID1.  If not specified, what
 504          * is a good choice?  We choose COUNTER_MAX / 2 arbitrarily.
 505          */
 506         write_behind = bitmap->mddev->bitmap_info.max_write_behind;
 507         if (write_behind > COUNTER_MAX)
 508                 write_behind = COUNTER_MAX / 2;
 509         sb->write_behind = cpu_to_le32(write_behind);
 510         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 511
 512         /* keep the array size field of the bitmap superblock up to date */
 513         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 514
 515         memcpy(sb->uuid, bitmap->mddev->uuid, 16);
 516
 517         set_bit(BITMAP_STALE, &bitmap->flags);
 518         sb->state = cpu_to_le32(bitmap->flags);
 519         bitmap->events_cleared = bitmap->mddev->events;
 520         sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
 521
 522         kunmap_atomic(sb);
 523
 524         return 0;
 525 }
 526
 527 /* read the superblock from the bitmap file and initialize some bitmap fields */
 528 static int bitmap_read_sb(struct bitmap *bitmap)
 529 {
 530         char *reason = NULL;
 531         bitmap_super_t *sb;
 532         unsigned long chunksize, daemon_sleep, write_behind;
 533         unsigned long long events;
 534         unsigned long sectors_reserved = 0;
 535         int err = -EINVAL;
 536         struct page *sb_page;
 537
 538         if (!bitmap->storage.file && !bitmap->mddev->bitmap_info.offset) {
 539                 chunksize = 128 * 1024 * 1024;
 540                 daemon_sleep = 5 * HZ;
 541                 write_behind = 0;
 542                 set_bit(BITMAP_STALE, &bitmap->flags);
 543                 err = 0;
 544                 goto out_no_sb;
 545         }
 546         /* page 0 is the superblock, read it... */
 547         sb_page = alloc_page(GFP_KERNEL);
 548         if (!sb_page)
 549                 return -ENOMEM;
 550         bitmap->storage.sb_page = sb_page;
 551
 552         if (bitmap->storage.file) {
 553                 loff_t isize = i_size_read(bitmap->storage.file->f_mapping->host);
 554                 int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
 555
 556                 err = read_page(bitmap->storage.file, 0,
 557                                 bitmap, bytes, sb_page);
 558         } else {
 559                 err = read_sb_page(bitmap->mddev,
 560                                    bitmap->mddev->bitmap_info.offset,
 561                                    sb_page,
 562                                    0, sizeof(bitmap_super_t));
 563         }
 564         if (err)
 565                 return err;
 566
 567         sb = kmap_atomic(sb_page);
 568
 569         chunksize = le32_to_cpu(sb->chunksize);
 570         daemon_sleep = le32_to_cpu(sb->daemon_sleep) * HZ;
 571         write_behind = le32_to_cpu(sb->write_behind);
 572         sectors_reserved = le32_to_cpu(sb->sectors_reserved);
 573
 574         /* verify that the bitmap-specific fields are valid */
 575         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
 576                 reason = "bad magic";
 577         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
 578                  le32_to_cpu(sb->version) > BITMAP_MAJOR_HI)
 579                 reason = "unrecognized superblock version";
 580         else if (chunksize < 512)
 581                 reason = "bitmap chunksize too small";
 582         else if (!is_power_of_2(chunksize))
 583                 reason = "bitmap chunksize not a power of 2";
 584         else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT)
 585                 reason = "daemon sleep period out of range";
 586         else if (write_behind > COUNTER_MAX)
 587                 reason = "write-behind limit out of range (0 - 16383)";
 588         if (reason) {
 589                 printk(KERN_INFO "%s: invalid bitmap file superblock: %s\n",
 590                         bmname(bitmap), reason);
 591                 goto out;
 592         }
 593
 594         /* keep the array size field of the bitmap superblock up to date */
 595         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 596
 597         if (bitmap->mddev->persistent) {
 598                 /*
 599                  * We have a persistent array superblock, so compare the
 600                  * bitmap's UUID and event counter to the mddev's
 601                  */
 602                 if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
 603                         printk(KERN_INFO
 604                                "%s: bitmap superblock UUID mismatch\n",
 605                                bmname(bitmap));
 606                         goto out;
 607                 }
 608                 events = le64_to_cpu(sb->events);
 609                 if (events < bitmap->mddev->events) {
 610                         printk(KERN_INFO
 611                                "%s: bitmap file is out of date (%llu < %llu) "
 612                                "-- forcing full recovery\n",
 613                                bmname(bitmap), events,
 614                                (unsigned long long) bitmap->mddev->events);
 615                         set_bit(BITMAP_STALE, &bitmap->flags);
 616                 }
 617         }
 618
 619         /* assign fields using values from superblock */
 620         bitmap->flags |= le32_to_cpu(sb->state);
 621         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
 622                 set_bit(BITMAP_HOSTENDIAN, &bitmap->flags);
 623         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
 624         err = 0;
 625 out:
 626         kunmap_atomic(sb);
 627 out_no_sb:
 628         if (test_bit(BITMAP_STALE, &bitmap->flags))
 629                 bitmap->events_cleared = bitmap->mddev->events;
 630         bitmap->mddev->bitmap_info.chunksize = chunksize;
 631         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 632         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 633         if (bitmap->mddev->bitmap_info.space == 0 ||
 634             bitmap->mddev->bitmap_info.space > sectors_reserved)
 635                 bitmap->mddev->bitmap_info.space = sectors_reserved;
 636         if (err)
 637                 bitmap_print_sb(bitmap);
 638         return err;
 639 }
 640
 641 /*
 642  * general bitmap file operations
 643  */
 644
 645 /*
 646  * on-disk bitmap:
 647  *
 648  * Use one bit per "chunk" (block set). We do the disk I/O on the bitmap
 649  * file a page at a time. There's a superblock at the start of the file.
 650  */
 651 /* calculate the index of the page that contains this bit */
 652 static inline unsigned long file_page_index(struct bitmap_storage *store,
 653                                             unsigned long chunk)
 654 {
 655         if (store->sb_page)
 656                 chunk += sizeof(bitmap_super_t) << 3;
 657         return chunk >> PAGE_BIT_SHIFT;
 658 }
 659
 660 /* calculate the (bit) offset of this bit within a page */
 661 static inline unsigned long file_page_offset(struct bitmap_storage *store,
 662                                              unsigned long chunk)
 663 {
 664         if (store->sb_page)
 665                 chunk += sizeof(bitmap_super_t) << 3;
 666         return chunk & (PAGE_BITS - 1);
 667 }
 668
 669 /*
 670  * return a pointer to the page in the filemap that contains the given bit
 671  *
 672  */
 673 static inline struct page *filemap_get_page(struct bitmap_storage *store,
 674                                             unsigned long chunk)
 675 {
 676         if (file_page_index(store, chunk) >= store->file_pages)
 677                 return NULL;
 678         return store->filemap[file_page_index(store, chunk)];
 679 }
 680
 681 static int bitmap_storage_alloc(struct bitmap_storage *store,
 682                                 unsigned long chunks, int with_super)
 683 {
 684         int pnum;
 685         unsigned long num_pages;
 686         unsigned long bytes;
 687
 688         bytes = DIV_ROUND_UP(chunks, 8);
 689         if (with_super)
 690                 bytes += sizeof(bitmap_super_t);
 691
 692         num_pages = DIV_ROUND_UP(bytes, PAGE_SIZE);
 693
 694         store->filemap = kmalloc(sizeof(struct page *)
 695                                  * num_pages, GFP_KERNEL);
 696         if (!store->filemap)
 697                 return -ENOMEM;
 698
 699         if (with_super && !store->sb_page) {
 700                 store->sb_page = alloc_page(GFP_KERNEL|__GFP_ZERO);
 701                 if (store->sb_page == NULL)
 702                         return -ENOMEM;
 703                 store->sb_page->index = 0;
 704         }
 705         pnum = 0;
 706         if (store->sb_page) {
 707                 store->filemap[0] = store->sb_page;
 708                 pnum = 1;
 709         }
 710         for ( ; pnum < num_pages; pnum++) {
 711                 store->filemap[pnum] = alloc_page(GFP_KERNEL|__GFP_ZERO);
 712                 if (!store->filemap[pnum]) {
 713                         store->file_pages = pnum;
 714                         return -ENOMEM;
 715                 }
 716                 store->filemap[pnum]->index = pnum;
 717         }
 718         store->file_pages = pnum;
 719
 720         /* We need 4 bits per page, rounded up to a multiple
 721          * of sizeof(unsigned long) */
 722         store->filemap_attr = kzalloc(
 723                 roundup(DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
 724                 GFP_KERNEL);
 725         if (!store->filemap_attr)
 726                 return -ENOMEM;
 727
 728         store->bytes = bytes;
 729
 730         return 0;
 731 }
 732
 733 static void bitmap_file_unmap(struct bitmap_storage *store)
 734 {
 735         struct page **map, *sb_page;
 736         int pages;
 737         struct file *file;
 738
 739         file = store->file;
 740         map = store->filemap;
 741         pages = store->file_pages;
 742         sb_page = store->sb_page;
 743
 744         while (pages--)
 745                 if (map[pages] != sb_page) /* 0 is sb_page, release it below */
 746                         free_buffers(map[pages]);
 747         kfree(map);
 748         kfree(store->filemap_attr);
 749
 750         if (sb_page)
 751                 free_buffers(sb_page);
 752
 753         if (file) {
 754                 struct inode *inode = file_inode(file);
 755                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
 756                 fput(file);
 757         }
 758 }
 759
 760 /*
 761  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
 762  * then it is no longer reliable, so we stop using it and we mark the file
 763  * as failed in the superblock
 764  */
 765 static void bitmap_file_kick(struct bitmap *bitmap)
 766 {
 767         char *path, *ptr = NULL;
 768
 769         if (!test_and_set_bit(BITMAP_STALE, &bitmap->flags)) {
 770                 bitmap_update_sb(bitmap);
 771
 772                 if (bitmap->storage.file) {
 773                         path = kmalloc(PAGE_SIZE, GFP_KERNEL);
 774                         if (path)
 775                                 ptr = d_path(&bitmap->storage.file->f_path,
 776                                              path, PAGE_SIZE);
 777
 778                         printk(KERN_ALERT
 779                               "%s: kicking failed bitmap file %s from array!\n",
 780                               bmname(bitmap), IS_ERR(ptr) ? "" : ptr);
 781
 782                         kfree(path);
 783                 } else
 784                         printk(KERN_ALERT
 785                                "%s: disabling internal bitmap due to errors\n",
 786                                bmname(bitmap));
 787         }
 788 }
 789
 790 enum bitmap_page_attr {
 791         BITMAP_PAGE_DIRTY = 0,     /* there are set bits that need to be synced */
 792         BITMAP_PAGE_PENDING = 1,   /* there are bits that are being cleaned.
 793                                     * i.e. counter is 1 or 2. */
 794         BITMAP_PAGE_NEEDWRITE = 2, /* there are cleared bits that need to be synced */
 795 };
 796
 797 static inline void set_page_attr(struct bitmap *bitmap, int pnum,
 798                                  enum bitmap_page_attr attr)
 799 {
 800         set_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 801 }
 802
 803 static inline void clear_page_attr(struct bitmap *bitmap, int pnum,
 804                                    enum bitmap_page_attr attr)
 805 {
 806         clear_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 807 }
 808
 809 static inline int test_page_attr(struct bitmap *bitmap, int pnum,
 810                                  enum bitmap_page_attr attr)
 811 {
 812         return test_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 813 }
 814
 815 static inline int test_and_clear_page_attr(struct bitmap *bitmap, int pnum,
 816                                            enum bitmap_page_attr attr)
 817 {
 818         return test_and_clear_bit((pnum<<2) + attr,
 819                                   bitmap->storage.filemap_attr);
 820 }
 821 /*
 822  * bitmap_file_set_bit -- called before performing a write to the md device
 823  * to set (and eventually sync) a particular bit in the bitmap file
 824  *
 825  * we set the bit immediately, then we record the page number so that
 826  * when an unplug occurs, we can flush the dirty pages out to disk
 827  */
 828 static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 829 {
 830         unsigned long bit;
 831         struct page *page;
 832         void *kaddr;
 833         unsigned long chunk = block >> bitmap->counts.chunkshift;
 834
 835         page = filemap_get_page(&bitmap->storage, chunk);
 836         if (!page)
 837                 return;
 838         bit = file_page_offset(&bitmap->storage, chunk);
 839
 840         /* set the bit */
 841         kaddr = kmap_atomic(page);
 842         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
 843                 set_bit(bit, kaddr);
 844         else
 845                 set_bit_le(bit, kaddr);
 846         kunmap_atomic(kaddr);
 847         pr_debug("set file bit %lu page %lu\n", bit, page->index);
 848         /* record page number so it gets flushed to disk when unplug occurs */
 849         set_page_attr(bitmap, page->index, BITMAP_PAGE_DIRTY);
 850 }
 851
 852 static void bitmap_file_clear_bit(struct bitmap *bitmap, sector_t block)
 853 {
 854         unsigned long bit;
 855         struct page *page;
 856         void *paddr;
 857         unsigned long chunk = block >> bitmap->counts.chunkshift;
 858
 859         page = filemap_get_page(&bitmap->storage, chunk);
 860         if (!page)
 861                 return;
 862         bit = file_page_offset(&bitmap->storage, chunk);
 863         paddr = kmap_atomic(page);
 864         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
 865                 clear_bit(bit, paddr);
 866         else
 867                 clear_bit_le(bit, paddr);
 868         kunmap_atomic(paddr);
 869         if (!test_page_attr(bitmap, page->index, BITMAP_PAGE_NEEDWRITE)) {
 870                 set_page_attr(bitmap, page->index, BITMAP_PAGE_PENDING);
 871                 bitmap->allclean = 0;
 872         }
 873 }
 874
 875 /* this gets called when the md device is ready to unplug its underlying
 876  * (slave) device queues -- before we let any writes go down, we need to
 877  * sync the dirty pages of the bitmap file to disk */
 878 void bitmap_unplug(struct bitmap *bitmap)
 879 {
 880         unsigned long i;
 881         int dirty, need_write;
 882
 883         if (!bitmap || !bitmap->storage.filemap ||
 884             test_bit(BITMAP_STALE, &bitmap->flags))
 885                 return;
 886
 887         /* look at each page to see if there are any set bits that need to be
 888          * flushed out to disk */
 889         for (i = 0; i < bitmap->storage.file_pages; i++) {
 890                 if (!bitmap->storage.filemap)
 891                         return;
 892                 dirty = test_and_clear_page_attr(bitmap, i, BITMAP_PAGE_DIRTY);
 893                 need_write = test_and_clear_page_attr(bitmap, i,
 894                                                       BITMAP_PAGE_NEEDWRITE);
 895                 if (dirty || need_write) {
 896                         clear_page_attr(bitmap, i, BITMAP_PAGE_PENDING);
 897                         write_page(bitmap, bitmap->storage.filemap[i], 0);
 898                 }
 899         }
 900         if (bitmap->storage.file)
 901                 wait_event(bitmap->write_wait,
 902                            atomic_read(&bitmap->pending_writes)==0);
 903         else
 904                 md_super_wait(bitmap->mddev);
 905
 906         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
 907                 bitmap_file_kick(bitmap);
 908 }
 909 EXPORT_SYMBOL(bitmap_unplug);
 910
 911 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
 912 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
 913  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
 914  * memory mapping of the bitmap file
 915  * Special cases:
 916  *   if there's no bitmap file, or if the bitmap file had been
 917  *   previously kicked from the array, we mark all the bits as
 918  *   1's in order to cause a full resync.
 919  *
 920  * We ignore all bits for sectors that end earlier than 'start'.
 921  * This is used when reading an out-of-date bitmap...
 922  */
 923 static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
 924 {
 925         unsigned long i, chunks, index, oldindex, bit;
 926         struct page *page = NULL;
 927         unsigned long bit_cnt = 0;
 928         struct file *file;
 929         unsigned long offset;
 930         int outofdate;
 931         int ret = -ENOSPC;
 932         void *paddr;
 933         struct bitmap_storage *store = &bitmap->storage;
 934
 935         chunks = bitmap->counts.chunks;
 936         file = store->file;
 937
 938         if (!file && !bitmap->mddev->bitmap_info.offset) {
 939                 /* No permanent bitmap - fill with '1s'. */
 940                 store->filemap = NULL;
 941                 store->file_pages = 0;
 942                 for (i = 0; i < chunks ; i++) {
 943                         /* if the disk bit is set, set the memory bit */
 944                         int needed = ((sector_t)(i+1) << (bitmap->counts.chunkshift)
 945                                       >= start);
 946                         bitmap_set_memory_bits(bitmap,
 947                                                (sector_t)i << bitmap->counts.chunkshift,
 948                                                needed);
 949                 }
 950                 return 0;
 951         }
 952
 953         outofdate = test_bit(BITMAP_STALE, &bitmap->flags);
 954         if (outofdate)
 955                 printk(KERN_INFO "%s: bitmap file is out of date, doing full "
 956                         "recovery\n", bmname(bitmap));
 957
 958         if (file && i_size_read(file->f_mapping->host) < store->bytes) {
 959                 printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
 960                        bmname(bitmap),
 961                        (unsigned long) i_size_read(file->f_mapping->host),
 962                        store->bytes);
 963                 goto err;
 964         }
 965
 966         oldindex = ~0L;
 967         offset = 0;
 968         if (!bitmap->mddev->bitmap_info.external)
 969                 offset = sizeof(bitmap_super_t);
 970
 971         for (i = 0; i < chunks; i++) {
 972                 int b;
 973                 index = file_page_index(&bitmap->storage, i);
 974                 bit = file_page_offset(&bitmap->storage, i);
 975                 if (index != oldindex) { /* this is a new page, read it in */
 976                         int count;
 977                         /* unmap the old page, we're done with it */
 978                         if (index == store->file_pages-1)
 979                                 count = store->bytes - index * PAGE_SIZE;
 980                         else
 981                                 count = PAGE_SIZE;
 982                         page = store->filemap[index];
 983                         if (file)
 984                                 ret = read_page(file, index, bitmap,
 985                                                 count, page);
 986                         else
 987                                 ret = read_sb_page(
 988                                         bitmap->mddev,
 989                                         bitmap->mddev->bitmap_info.offset,
 990                                         page,
 991                                         index, count);
 992
 993                         if (ret)
 994                                 goto err;
 995
 996                         oldindex = index;
 997
 998                         if (outofdate) {
 999                                 /*
1000                                  * if bitmap is out of date, dirty the
1001                                  * whole page and write it out
1002                                  */
1003                                 paddr = kmap_atomic(page);
1004                                 memset(paddr + offset, 0xff,
1005                                        PAGE_SIZE - offset);
1006                                 kunmap_atomic(paddr);
1007                                 write_page(bitmap, page, 1);
1008
1009                                 ret = -EIO;
1010                                 if (test_bit(BITMAP_WRITE_ERROR,
1011                                              &bitmap->flags))
1012                                         goto err;
1013                         }
1014                 }
1015                 paddr = kmap_atomic(page);
1016                 if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
1017                         b = test_bit(bit, paddr);
1018                 else
1019                         b = test_bit_le(bit, paddr);
1020                 kunmap_atomic(paddr);
1021                 if (b) {
1022                         /* if the disk bit is set, set the memory bit */
1023                         int needed = ((sector_t)(i+1) << bitmap->counts.chunkshift
1024                                       >= start);
1025                         bitmap_set_memory_bits(bitmap,
1026                                                (sector_t)i << bitmap->counts.chunkshift,
1027                                                needed);
1028                         bit_cnt++;
1029                 }
1030                 offset = 0;
1031         }
1032
1033         printk(KERN_INFO "%s: bitmap initialized from disk: "
1034                "read %lu pages, set %lu of %lu bits\n",
1035                bmname(bitmap), store->file_pages,
1036                bit_cnt, chunks);
1037
1038         return 0;
1039
1040  err:
1041         printk(KERN_INFO "%s: bitmap initialisation failed: %d\n",
1042                bmname(bitmap), ret);
1043         return ret;
1044 }
1045
1046 void bitmap_write_all(struct bitmap *bitmap)
1047 {
1048         /* We don't actually write all bitmap blocks here,
1049          * just flag them as needing to be written
1050          */
1051         int i;
1052
1053         if (!bitmap || !bitmap->storage.filemap)
1054                 return;
1055         if (bitmap->storage.file)
1056                 /* Only one copy, so nothing needed */
1057                 return;
1058
1059         for (i = 0; i < bitmap->storage.file_pages; i++)
1060                 set_page_attr(bitmap, i,
1061                               BITMAP_PAGE_NEEDWRITE);
1062         bitmap->allclean = 0;
1063 }
1064
1065 static void bitmap_count_page(struct bitmap_counts *bitmap,
1066                               sector_t offset, int inc)
1067 {
1068         sector_t chunk = offset >> bitmap->chunkshift;
1069         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1070         bitmap->bp[page].count += inc;
1071         bitmap_checkfree(bitmap, page);
1072 }
1073
1074 static void bitmap_set_pending(struct bitmap_counts *bitmap, sector_t offset)
1075 {
1076         sector_t chunk = offset >> bitmap->chunkshift;
1077         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1078         struct bitmap_page *bp = &bitmap->bp[page];
1079
1080         if (!bp->pending)
1081                 bp->pending = 1;
1082 }
1083
1084 static bitmap_counter_t *bitmap_get_counter(struct bitmap_counts *bitmap,
1085                                             sector_t offset, sector_t *blocks,
1086                                             int create);
1087
1088 /*
1089  * bitmap daemon -- periodically wakes up to clean bits and flush pages
1090  *                      out to disk
1091  */
1092
1093 void bitmap_daemon_work(struct mddev *mddev)
1094 {
1095         struct bitmap *bitmap;
1096         unsigned long j;
1097         unsigned long nextpage;
1098         sector_t blocks;
1099         struct bitmap_counts *counts;
1100
1101         /* Use a mutex to guard daemon_work against
1102          * bitmap_destroy.
1103          */
1104         mutex_lock(&mddev->bitmap_info.mutex);
1105         bitmap = mddev->bitmap;
1106         if (bitmap == NULL) {
1107                 mutex_unlock(&mddev->bitmap_info.mutex);
1108                 return;
1109         }
1110         if (time_before(jiffies, bitmap->daemon_lastrun
1111                         + mddev->bitmap_info.daemon_sleep))
1112                 goto done;
1113
1114         bitmap->daemon_lastrun = jiffies;
1115         if (bitmap->allclean) {
1116                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1117                 goto done;
1118         }
1119         bitmap->allclean = 1;
1120
1121         /* Any file-page which is PENDING now needs to be written.
1122          * So set NEEDWRITE now, then after we make any last-minute changes
1123          * we will write it.
1124          */
1125         for (j = 0; j < bitmap->storage.file_pages; j++)
1126                 if (test_and_clear_page_attr(bitmap, j,
1127                                              BITMAP_PAGE_PENDING))
1128                         set_page_attr(bitmap, j,
1129                                       BITMAP_PAGE_NEEDWRITE);
1130
1131         if (bitmap->need_sync &&
1132             mddev->bitmap_info.external == 0) {
1133                 /* Arrange for superblock update as well as
1134                  * other changes */
1135                 bitmap_super_t *sb;
1136                 bitmap->need_sync = 0;
1137                 if (bitmap->storage.filemap) {
1138                         sb = kmap_atomic(bitmap->storage.sb_page);
1139                         sb->events_cleared =
1140                                 cpu_to_le64(bitmap->events_cleared);
1141                         kunmap_atomic(sb);
1142                         set_page_attr(bitmap, 0,
1143                                       BITMAP_PAGE_NEEDWRITE);
1144                 }
1145         }
1146         /* Now look at the bitmap counters and if any are '2' or '1',
1147          * decrement and handle accordingly.
1148          */
1149         counts = &bitmap->counts;
1150         spin_lock_irq(&counts->lock);
1151         nextpage = 0;
1152         for (j = 0; j < counts->chunks; j++) {
1153                 bitmap_counter_t *bmc;
1154                 sector_t  block = (sector_t)j << counts->chunkshift;
1155
1156                 if (j == nextpage) {
1157                         nextpage += PAGE_COUNTER_RATIO;
1158                         if (!counts->bp[j >> PAGE_COUNTER_SHIFT].pending) {
1159                                 j |= PAGE_COUNTER_MASK;
1160                                 continue;
1161                         }
1162                         counts->bp[j >> PAGE_COUNTER_SHIFT].pending = 0;
1163                 }
1164                 bmc = bitmap_get_counter(counts,
1165                                          block,
1166                                          &blocks, 0);
1167
1168                 if (!bmc) {
1169                         j |= PAGE_COUNTER_MASK;
1170                         continue;
1171                 }
1172                 if (*bmc == 1 && !bitmap->need_sync) {
1173                         /* We can clear the bit */
1174                         *bmc = 0;
1175                         bitmap_count_page(counts, block, -1);
1176                         bitmap_file_clear_bit(bitmap, block);
1177                 } else if (*bmc && *bmc <= 2) {
1178                         *bmc = 1;
1179                         bitmap_set_pending(counts, block);
1180                         bitmap->allclean = 0;
1181                 }
1182         }
1183         spin_unlock_irq(&counts->lock);
1184
1185         /* Now start writeout on any page in NEEDWRITE that isn't DIRTY.
1186          * DIRTY pages need to be written by bitmap_unplug so it can wait
1187          * for them.
1188          * If we find any DIRTY page we stop there and let bitmap_unplug
1189          * handle all the rest.  This is important in the case where
1190          * the first blocking holds the superblock and it has been updated.
1191          * We mustn't write any other blocks before the superblock.
1192          */
1193         for (j = 0;
1194              j < bitmap->storage.file_pages
1195                      && !test_bit(BITMAP_STALE, &bitmap->flags);
1196              j++) {
1197
1198                 if (test_page_attr(bitmap, j,
1199                                    BITMAP_PAGE_DIRTY))
1200                         /* bitmap_unplug will handle the rest */
1201                         break;
1202                 if (test_and_clear_page_attr(bitmap, j,
1203                                              BITMAP_PAGE_NEEDWRITE)) {
1204                         write_page(bitmap, bitmap->storage.filemap[j], 0);
1205                 }
1206         }
1207
1208  done:
1209         if (bitmap->allclean == 0)
1210                 mddev->thread->timeout =
1211                         mddev->bitmap_info.daemon_sleep;
1212         mutex_unlock(&mddev->bitmap_info.mutex);
1213 }
1214
1215 static bitmap_counter_t *bitmap_get_counter(struct bitmap_counts *bitmap,
1216                                             sector_t offset, sector_t *blocks,
1217                                             int create)
1218 __releases(bitmap->lock)
1219 __acquires(bitmap->lock)
1220 {
1221         /* If 'create', we might release the lock and reclaim it.
1222          * The lock must have been taken with interrupts enabled.
1223          * If !create, we don't release the lock.
1224          */
1225         sector_t chunk = offset >> bitmap->chunkshift;
1226         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1227         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1228         sector_t csize;
1229         int err;
1230
1231         err = bitmap_checkpage(bitmap, page, create);
1232
1233         if (bitmap->bp[page].hijacked ||
1234             bitmap->bp[page].map == NULL)
1235                 csize = ((sector_t)1) << (bitmap->chunkshift +
1236                                           PAGE_COUNTER_SHIFT - 1);
1237         else
1238                 csize = ((sector_t)1) << bitmap->chunkshift;
1239         *blocks = csize - (offset & (csize - 1));
1240
1241         if (err < 0)
1242                 return NULL;
1243
1244         /* now locked ... */
1245
1246         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1247                 /* should we use the first or second counter field
1248                  * of the hijacked pointer? */
1249                 int hi = (pageoff > PAGE_COUNTER_MASK);
1250                 return  &((bitmap_counter_t *)
1251                           &bitmap->bp[page].map)[hi];
1252         } else /* page is allocated */
1253                 return (bitmap_counter_t *)
1254                         &(bitmap->bp[page].map[pageoff]);
1255 }
1256
1257 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1258 {
1259         if (!bitmap)
1260                 return 0;
1261
1262         if (behind) {
1263                 int bw;
1264                 atomic_inc(&bitmap->behind_writes);
1265                 bw = atomic_read(&bitmap->behind_writes);
1266                 if (bw > bitmap->behind_writes_used)
1267                         bitmap->behind_writes_used = bw;
1268
1269                 pr_debug("inc write-behind count %d/%lu\n",
1270                          bw, bitmap->mddev->bitmap_info.max_write_behind);
1271         }
1272
1273         while (sectors) {
1274                 sector_t blocks;
1275                 bitmap_counter_t *bmc;
1276
1277                 spin_lock_irq(&bitmap->counts.lock);
1278                 bmc = bitmap_get_counter(&bitmap->counts, offset, &blocks, 1);
1279                 if (!bmc) {
1280                         spin_unlock_irq(&bitmap->counts.lock);
1281                         return 0;
1282                 }
1283
1284                 if (unlikely(COUNTER(*bmc) == COUNTER_MAX)) {
1285                         DEFINE_WAIT(__wait);
1286                         /* note that it is safe to do the prepare_to_wait
1287                          * after the test as long as we do it before dropping
1288                          * the spinlock.
1289                          */
1290                         prepare_to_wait(&bitmap->overflow_wait, &__wait,
1291                                         TASK_UNINTERRUPTIBLE);
1292                         spin_unlock_irq(&bitmap->counts.lock);
1293                         schedule();
1294                         finish_wait(&bitmap->overflow_wait, &__wait);
1295                         continue;
1296                 }
1297
1298                 switch (*bmc) {
1299                 case 0:
1300                         bitmap_file_set_bit(bitmap, offset);
1301                         bitmap_count_page(&bitmap->counts, offset, 1);
1302                         /* fall through */
1303                 case 1:
1304                         *bmc = 2;
1305                 }
1306
1307                 (*bmc)++;
1308
1309                 spin_unlock_irq(&bitmap->counts.lock);
1310
1311                 offset += blocks;
1312                 if (sectors > blocks)
1313                         sectors -= blocks;
1314                 else
1315                         sectors = 0;
1316         }
1317         return 0;
1318 }
1319 EXPORT_SYMBOL(bitmap_startwrite);
1320
1321 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1322                      int success, int behind)
1323 {
1324         if (!bitmap)
1325                 return;
1326         if (behind) {
1327                 if (atomic_dec_and_test(&bitmap->behind_writes))
1328                         wake_up(&bitmap->behind_wait);
1329                 pr_debug("dec write-behind count %d/%lu\n",
1330                          atomic_read(&bitmap->behind_writes),
1331                          bitmap->mddev->bitmap_info.max_write_behind);
1332         }
1333
1334         while (sectors) {
1335                 sector_t blocks;
1336                 unsigned long flags;
1337                 bitmap_counter_t *bmc;
1338
1339                 spin_lock_irqsave(&bitmap->counts.lock, flags);
1340                 bmc = bitmap_get_counter(&bitmap->counts, offset, &blocks, 0);
1341                 if (!bmc) {
1342                         spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1343                         return;
1344                 }
1345
1346                 if (success && !bitmap->mddev->degraded &&
1347                     bitmap->events_cleared < bitmap->mddev->events) {
1348                         bitmap->events_cleared = bitmap->mddev->events;
1349                         bitmap->need_sync = 1;
1350                         sysfs_notify_dirent_safe(bitmap->sysfs_can_clear);
1351                 }
1352
1353                 if (!success && !NEEDED(*bmc))
1354                         *bmc |= NEEDED_MASK;
1355
1356                 if (COUNTER(*bmc) == COUNTER_MAX)
1357                         wake_up(&bitmap->overflow_wait);
1358
1359                 (*bmc)--;
1360                 if (*bmc <= 2) {
1361                         bitmap_set_pending(&bitmap->counts, offset);
1362                         bitmap->allclean = 0;
1363                 }
1364                 spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1365                 offset += blocks;
1366                 if (sectors > blocks)
1367                         sectors -= blocks;
1368                 else
1369                         sectors = 0;
1370         }
1371 }
1372 EXPORT_SYMBOL(bitmap_endwrite);
1373
1374 static int __bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1375                                int degraded)
1376 {
1377         bitmap_counter_t *bmc;
1378         int rv;
1379         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1380                 *blocks = 1024;
1381                 return 1; /* always resync if no bitmap */
1382         }
1383         spin_lock_irq(&bitmap->counts.lock);
1384         bmc = bitmap_get_counter(&bitmap->counts, offset, blocks, 0);
1385         rv = 0;
1386         if (bmc) {
1387                 /* locked */
1388                 if (RESYNC(*bmc))
1389                         rv = 1;
1390                 else if (NEEDED(*bmc)) {
1391                         rv = 1;
1392                         if (!degraded) { /* don't set/clear bits if degraded */
1393                                 *bmc |= RESYNC_MASK;
1394                                 *bmc &= ~NEEDED_MASK;
1395                         }
1396                 }
1397         }
1398         spin_unlock_irq(&bitmap->counts.lock);
1399         return rv;
1400 }
1401
1402 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1403                       int degraded)
1404 {
1405         /* bitmap_start_sync must always report on multiples of whole
1406          * pages, otherwise resync (which is very PAGE_SIZE based) will
1407          * get confused.
1408          * So call __bitmap_start_sync repeatedly (if needed) until
1409          * At least PAGE_SIZE>>9 blocks are covered.
1410          * Return the 'or' of the result.
1411          */
1412         int rv = 0;
1413         sector_t blocks1;
1414
1415         *blocks = 0;
1416         while (*blocks < (PAGE_SIZE>>9)) {
1417                 rv |= __bitmap_start_sync(bitmap, offset,
1418                                           &blocks1, degraded);
1419                 offset += blocks1;
1420                 *blocks += blocks1;
1421         }
1422         return rv;
1423 }
1424 EXPORT_SYMBOL(bitmap_start_sync);
1425
1426 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks, int aborted)
1427 {
1428         bitmap_counter_t *bmc;
1429         unsigned long flags;
1430
1431         if (bitmap == NULL) {
1432                 *blocks = 1024;
1433                 return;
1434         }
1435         spin_lock_irqsave(&bitmap->counts.lock, flags);
1436         bmc = bitmap_get_counter(&bitmap->counts, offset, blocks, 0);
1437         if (bmc == NULL)
1438                 goto unlock;
1439         /* locked */
1440         if (RESYNC(*bmc)) {
1441                 *bmc &= ~RESYNC_MASK;
1442
1443                 if (!NEEDED(*bmc) && aborted)
1444                         *bmc |= NEEDED_MASK;
1445                 else {
1446                         if (*bmc <= 2) {
1447                                 bitmap_set_pending(&bitmap->counts, offset);
1448                                 bitmap->allclean = 0;
1449                         }
1450                 }
1451         }
1452  unlock:
1453         spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1454 }
1455 EXPORT_SYMBOL(bitmap_end_sync);
1456
1457 void bitmap_close_sync(struct bitmap *bitmap)
1458 {
1459         /* Sync has finished, and any bitmap chunks that weren't synced
1460          * properly have been aborted.  It remains to us to clear the
1461          * RESYNC bit wherever it is still on
1462          */
1463         sector_t sector = 0;
1464         sector_t blocks;
1465         if (!bitmap)
1466                 return;
1467         while (sector < bitmap->mddev->resync_max_sectors) {
1468                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1469                 sector += blocks;
1470         }
1471 }
1472 EXPORT_SYMBOL(bitmap_close_sync);
1473
1474 void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector)
1475 {
1476         sector_t s = 0;
1477         sector_t blocks;
1478
1479         if (!bitmap)
1480                 return;
1481         if (sector == 0) {
1482                 bitmap->last_end_sync = jiffies;
1483                 return;
1484         }
1485         if (time_before(jiffies, (bitmap->last_end_sync
1486                                   + bitmap->mddev->bitmap_info.daemon_sleep)))
1487                 return;
1488         wait_event(bitmap->mddev->recovery_wait,
1489                    atomic_read(&bitmap->mddev->recovery_active) == 0);
1490
1491         bitmap->mddev->curr_resync_completed = sector;
1492         set_bit(MD_CHANGE_CLEAN, &bitmap->mddev->flags);
1493         sector &= ~((1ULL << bitmap->counts.chunkshift) - 1);
1494         s = 0;
1495         while (s < sector && s < bitmap->mddev->resync_max_sectors) {
1496                 bitmap_end_sync(bitmap, s, &blocks, 0);
1497                 s += blocks;
1498         }
1499         bitmap->last_end_sync = jiffies;
1500         sysfs_notify(&bitmap->mddev->kobj, NULL, "sync_completed");
1501 }
1502 EXPORT_SYMBOL(bitmap_cond_end_sync);
1503
1504 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1505 {
1506         /* For each chunk covered by any of these sectors, set the
1507          * counter to 2 and possibly set resync_needed.  They should all
1508          * be 0 at this point
1509          */
1510
1511         sector_t secs;
1512         bitmap_counter_t *bmc;
1513         spin_lock_irq(&bitmap->counts.lock);
1514         bmc = bitmap_get_counter(&bitmap->counts, offset, &secs, 1);
1515         if (!bmc) {
1516                 spin_unlock_irq(&bitmap->counts.lock);
1517                 return;
1518         }
1519         if (!*bmc) {
1520                 *bmc = 2 | (needed ? NEEDED_MASK : 0);
1521                 bitmap_count_page(&bitmap->counts, offset, 1);
1522                 bitmap_set_pending(&bitmap->counts, offset);
1523                 bitmap->allclean = 0;
1524         }
1525         spin_unlock_irq(&bitmap->counts.lock);
1526 }
1527
1528 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
1529 void bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1530 {
1531         unsigned long chunk;
1532
1533         for (chunk = s; chunk <= e; chunk++) {
1534                 sector_t sec = (sector_t)chunk << bitmap->counts.chunkshift;
1535                 bitmap_set_memory_bits(bitmap, sec, 1);
1536                 bitmap_file_set_bit(bitmap, sec);
1537                 if (sec < bitmap->mddev->recovery_cp)
1538                         /* We are asserting that the array is dirty,
1539                          * so move the recovery_cp address back so
1540                          * that it is obvious that it is dirty
1541                          */
1542                         bitmap->mddev->recovery_cp = sec;
1543         }
1544 }
1545
1546 /*
1547  * flush out any pending updates
1548  */
1549 void bitmap_flush(struct mddev *mddev)
1550 {
1551         struct bitmap *bitmap = mddev->bitmap;
1552         long sleep;
1553
1554         if (!bitmap) /* there was no bitmap */
1555                 return;
1556
1557         /* run the daemon_work three time to ensure everything is flushed
1558          * that can be
1559          */
1560         sleep = mddev->bitmap_info.daemon_sleep * 2;
1561         bitmap->daemon_lastrun -= sleep;
1562         bitmap_daemon_work(mddev);
1563         bitmap->daemon_lastrun -= sleep;
1564         bitmap_daemon_work(mddev);
1565         bitmap->daemon_lastrun -= sleep;
1566         bitmap_daemon_work(mddev);
1567         bitmap_update_sb(bitmap);
1568 }
1569
1570 /*
1571  * free memory that was allocated
1572  */
1573 static void bitmap_free(struct bitmap *bitmap)
1574 {
1575         unsigned long k, pages;
1576         struct bitmap_page *bp;
1577
1578         if (!bitmap) /* there was no bitmap */
1579                 return;
1580
1581         /* Shouldn't be needed - but just in case.... */
1582         wait_event(bitmap->write_wait,
1583                    atomic_read(&bitmap->pending_writes) == 0);
1584
1585         /* release the bitmap file  */
1586         bitmap_file_unmap(&bitmap->storage);
1587
1588         bp = bitmap->counts.bp;
1589         pages = bitmap->counts.pages;
1590
1591         /* free all allocated memory */
1592
1593         if (bp) /* deallocate the page memory */
1594                 for (k = 0; k < pages; k++)
1595                         if (bp[k].map && !bp[k].hijacked)
1596                                 kfree(bp[k].map);
1597         kfree(bp);
1598         kfree(bitmap);
1599 }
1600
1601 void bitmap_destroy(struct mddev *mddev)
1602 {
1603         struct bitmap *bitmap = mddev->bitmap;
1604
1605         if (!bitmap) /* there was no bitmap */
1606                 return;
1607
1608         mutex_lock(&mddev->bitmap_info.mutex);
1609         mddev->bitmap = NULL; /* disconnect from the md device */
1610         mutex_unlock(&mddev->bitmap_info.mutex);
1611         if (mddev->thread)
1612                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1613
1614         if (bitmap->sysfs_can_clear)
1615                 sysfs_put(bitmap->sysfs_can_clear);
1616
1617         bitmap_free(bitmap);
1618 }
1619
1620 /*
1621  * initialize the bitmap structure
1622  * if this returns an error, bitmap_destroy must be called to do clean up
1623  */
1624 int bitmap_create(struct mddev *mddev)
1625 {
1626         struct bitmap *bitmap;
1627         sector_t blocks = mddev->resync_max_sectors;
1628         struct file *file = mddev->bitmap_info.file;
1629         int err;
1630         struct kernfs_node *bm = NULL;
1631
1632         BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
1633
1634         BUG_ON(file && mddev->bitmap_info.offset);
1635
1636         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1637         if (!bitmap)
1638                 return -ENOMEM;
1639
1640         spin_lock_init(&bitmap->counts.lock);
1641         atomic_set(&bitmap->pending_writes, 0);
1642         init_waitqueue_head(&bitmap->write_wait);
1643         init_waitqueue_head(&bitmap->overflow_wait);
1644         init_waitqueue_head(&bitmap->behind_wait);
1645
1646         bitmap->mddev = mddev;
1647
1648         if (mddev->kobj.sd)
1649                 bm = sysfs_get_dirent(mddev->kobj.sd, "bitmap");
1650         if (bm) {
1651                 bitmap->sysfs_can_clear = sysfs_get_dirent(bm, "can_clear");
1652                 sysfs_put(bm);
1653         } else
1654                 bitmap->sysfs_can_clear = NULL;
1655
1656         bitmap->storage.file = file;
1657         if (file) {
1658                 get_file(file);
1659                 /* As future accesses to this file will use bmap,
1660                  * and bypass the page cache, we must sync the file
1661                  * first.
1662                  */
1663                 vfs_fsync(file, 1);
1664         }
1665         /* read superblock from bitmap file (this sets mddev->bitmap_info.chunksize) */
1666         if (!mddev->bitmap_info.external) {
1667                 /*
1668                  * If 'MD_ARRAY_FIRST_USE' is set, then device-mapper is
1669                  * instructing us to create a new on-disk bitmap instance.
1670                  */
1671                 if (test_and_clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags))
1672                         err = bitmap_new_disk_sb(bitmap);
1673                 else
1674                         err = bitmap_read_sb(bitmap);
1675         } else {
1676                 err = 0;
1677                 if (mddev->bitmap_info.chunksize == 0 ||
1678                     mddev->bitmap_info.daemon_sleep == 0)
1679                         /* chunksize and time_base need to be
1680                          * set first. */
1681                         err = -EINVAL;
1682         }
1683         if (err)
1684                 goto error;
1685
1686         bitmap->daemon_lastrun = jiffies;
1687         err = bitmap_resize(bitmap, blocks, mddev->bitmap_info.chunksize, 1);
1688         if (err)
1689                 goto error;
1690
1691         printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
1692                bitmap->counts.pages, bmname(bitmap));
1693
1694         mddev->bitmap = bitmap;
1695         return test_bit(BITMAP_WRITE_ERROR, &bitmap->flags) ? -EIO : 0;
1696
1697  error:
1698         bitmap_free(bitmap);
1699         return err;
1700 }
1701
1702 int bitmap_load(struct mddev *mddev)
1703 {
1704         int err = 0;
1705         sector_t start = 0;
1706         sector_t sector = 0;
1707         struct bitmap *bitmap = mddev->bitmap;
1708
1709         if (!bitmap)
1710                 goto out;
1711
1712         /* Clear out old bitmap info first:  Either there is none, or we
1713          * are resuming after someone else has possibly changed things,
1714          * so we should forget old cached info.
1715          * All chunks should be clean, but some might need_sync.
1716          */
1717         while (sector < mddev->resync_max_sectors) {
1718                 sector_t blocks;
1719                 bitmap_start_sync(bitmap, sector, &blocks, 0);
1720                 sector += blocks;
1721         }
1722         bitmap_close_sync(bitmap);
1723
1724         if (mddev->degraded == 0
1725             || bitmap->events_cleared == mddev->events)
1726                 /* no need to keep dirty bits to optimise a
1727                  * re-add of a missing device */
1728                 start = mddev->recovery_cp;
1729
1730         mutex_lock(&mddev->bitmap_info.mutex);
1731         err = bitmap_init_from_disk(bitmap, start);
1732         mutex_unlock(&mddev->bitmap_info.mutex);
1733
1734         if (err)
1735                 goto out;
1736         clear_bit(BITMAP_STALE, &bitmap->flags);
1737
1738         /* Kick recovery in case any bits were set */
1739         set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
1740
1741         mddev->thread->timeout = mddev->bitmap_info.daemon_sleep;
1742         md_wakeup_thread(mddev->thread);
1743
1744         bitmap_update_sb(bitmap);
1745
1746         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
1747                 err = -EIO;
1748 out:
1749         return err;
1750 }
1751 EXPORT_SYMBOL_GPL(bitmap_load);
1752
1753 void bitmap_status(struct seq_file *seq, struct bitmap *bitmap)
1754 {
1755         unsigned long chunk_kb;
1756         struct bitmap_counts *counts;
1757
1758         if (!bitmap)
1759                 return;
1760
1761         counts = &bitmap->counts;
1762
1763         chunk_kb = bitmap->mddev->bitmap_info.chunksize >> 10;
1764         seq_printf(seq, "bitmap: %lu/%lu pages [%luKB], "
1765                    "%lu%s chunk",
1766                    counts->pages - counts->missing_pages,
1767                    counts->pages,
1768                    (counts->pages - counts->missing_pages)
1769                    << (PAGE_SHIFT - 10),
1770                    chunk_kb ? chunk_kb : bitmap->mddev->bitmap_info.chunksize,
1771                    chunk_kb ? "KB" : "B");
1772         if (bitmap->storage.file) {
1773                 seq_printf(seq, ", file: ");
1774                 seq_path(seq, &bitmap->storage.file->f_path, " \t\n");
1775         }
1776
1777         seq_printf(seq, "\n");
1778 }
1779
1780 int bitmap_resize(struct bitmap *bitmap, sector_t blocks,
1781                   int chunksize, int init)
1782 {
1783         /* If chunk_size is 0, choose an appropriate chunk size.
1784          * Then possibly allocate new storage space.
1785          * Then quiesce, copy bits, replace bitmap, and re-start
1786          *
1787          * This function is called both to set up the initial bitmap
1788          * and to resize the bitmap while the array is active.
1789          * If this happens as a result of the array being resized,
1790          * chunksize will be zero, and we need to choose a suitable
1791          * chunksize, otherwise we use what we are given.
1792          */
1793         struct bitmap_storage store;
1794         struct bitmap_counts old_counts;
1795         unsigned long chunks;
1796         sector_t block;
1797         sector_t old_blocks, new_blocks;
1798         int chunkshift;
1799         int ret = 0;
1800         long pages;
1801         struct bitmap_page *new_bp;
1802
1803         if (chunksize == 0) {
1804                 /* If there is enough space, leave the chunk size unchanged,
1805                  * else increase by factor of two until there is enough space.
1806                  */
1807                 long bytes;
1808                 long space = bitmap->mddev->bitmap_info.space;
1809
1810                 if (space == 0) {
1811                         /* We don't know how much space there is, so limit
1812                          * to current size - in sectors.
1813                          */
1814                         bytes = DIV_ROUND_UP(bitmap->counts.chunks, 8);
1815                         if (!bitmap->mddev->bitmap_info.external)
1816                                 bytes += sizeof(bitmap_super_t);
1817                         space = DIV_ROUND_UP(bytes, 512);
1818                         bitmap->mddev->bitmap_info.space = space;
1819                 }
1820                 chunkshift = bitmap->counts.chunkshift;
1821                 chunkshift--;
1822                 do {
1823                         /* 'chunkshift' is shift from block size to chunk size */
1824                         chunkshift++;
1825                         chunks = DIV_ROUND_UP_SECTOR_T(blocks, 1 << chunkshift);
1826                         bytes = DIV_ROUND_UP(chunks, 8);
1827                         if (!bitmap->mddev->bitmap_info.external)
1828                                 bytes += sizeof(bitmap_super_t);
1829                 } while (bytes > (space << 9));
1830         } else
1831                 chunkshift = ffz(~chunksize) - BITMAP_BLOCK_SHIFT;
1832
1833         chunks = DIV_ROUND_UP_SECTOR_T(blocks, 1 << chunkshift);
1834         memset(&store, 0, sizeof(store));
1835         if (bitmap->mddev->bitmap_info.offset || bitmap->mddev->bitmap_info.file)
1836                 ret = bitmap_storage_alloc(&store, chunks,
1837                                            !bitmap->mddev->bitmap_info.external);
1838         if (ret)
1839                 goto err;
1840
1841         pages = DIV_ROUND_UP(chunks, PAGE_COUNTER_RATIO);
1842
1843         new_bp = kzalloc(pages * sizeof(*new_bp), GFP_KERNEL);
1844         ret = -ENOMEM;
1845         if (!new_bp) {
1846                 bitmap_file_unmap(&store);
1847                 goto err;
1848         }
1849
1850         if (!init)
1851                 bitmap->mddev->pers->quiesce(bitmap->mddev, 1);
1852
1853         store.file = bitmap->storage.file;
1854         bitmap->storage.file = NULL;
1855
1856         if (store.sb_page && bitmap->storage.sb_page)
1857                 memcpy(page_address(store.sb_page),
1858                        page_address(bitmap->storage.sb_page),
1859                        sizeof(bitmap_super_t));
1860         bitmap_file_unmap(&bitmap->storage);
1861         bitmap->storage = store;
1862
1863         old_counts = bitmap->counts;
1864         bitmap->counts.bp = new_bp;
1865         bitmap->counts.pages = pages;
1866         bitmap->counts.missing_pages = pages;
1867         bitmap->counts.chunkshift = chunkshift;
1868         bitmap->counts.chunks = chunks;
1869         bitmap->mddev->bitmap_info.chunksize = 1 << (chunkshift +
1870                                                      BITMAP_BLOCK_SHIFT);
1871
1872         blocks = min(old_counts.chunks << old_counts.chunkshift,
1873                      chunks << chunkshift);
1874
1875         spin_lock_irq(&bitmap->counts.lock);
1876         for (block = 0; block < blocks; ) {
1877                 bitmap_counter_t *bmc_old, *bmc_new;
1878                 int set;
1879
1880                 bmc_old = bitmap_get_counter(&old_counts, block,
1881                                              &old_blocks, 0);
1882                 set = bmc_old && NEEDED(*bmc_old);
1883
1884                 if (set) {
1885                         bmc_new = bitmap_get_counter(&bitmap->counts, block,
1886                                                      &new_blocks, 1);
1887                         if (*bmc_new == 0) {
1888                                 /* need to set on-disk bits too. */
1889                                 sector_t end = block + new_blocks;
1890                                 sector_t start = block >> chunkshift;
1891                                 start <<= chunkshift;
1892                                 while (start < end) {
1893                                         bitmap_file_set_bit(bitmap, block);
1894                                         start += 1 << chunkshift;
1895                                 }
1896                                 *bmc_new = 2;
1897                                 bitmap_count_page(&bitmap->counts,
1898                                                   block, 1);
1899                                 bitmap_set_pending(&bitmap->counts,
1900                                                    block);
1901                         }
1902                         *bmc_new |= NEEDED_MASK;
1903                         if (new_blocks < old_blocks)
1904                                 old_blocks = new_blocks;
1905                 }
1906                 block += old_blocks;
1907         }
1908
1909         if (!init) {
1910                 int i;
1911                 while (block < (chunks << chunkshift)) {
1912                         bitmap_counter_t *bmc;
1913                         bmc = bitmap_get_counter(&bitmap->counts, block,
1914                                                  &new_blocks, 1);
1915                         if (bmc) {
1916                                 /* new space.  It needs to be resynced, so
1917                                  * we set NEEDED_MASK.
1918                                  */
1919                                 if (*bmc == 0) {
1920                                         *bmc = NEEDED_MASK | 2;
1921                                         bitmap_count_page(&bitmap->counts,
1922                                                           block, 1);
1923                                         bitmap_set_pending(&bitmap->counts,
1924                                                            block);
1925                                 }
1926                         }
1927                         block += new_blocks;
1928                 }
1929                 for (i = 0; i < bitmap->storage.file_pages; i++)
1930                         set_page_attr(bitmap, i, BITMAP_PAGE_DIRTY);
1931         }
1932         spin_unlock_irq(&bitmap->counts.lock);
1933
1934         if (!init) {
1935                 bitmap_unplug(bitmap);
1936                 bitmap->mddev->pers->quiesce(bitmap->mddev, 0);
1937         }
1938         ret = 0;
1939 err:
1940         return ret;
1941 }
1942 EXPORT_SYMBOL_GPL(bitmap_resize);
1943
1944 static ssize_t
1945 location_show(struct mddev *mddev, char *page)
1946 {
1947         ssize_t len;
1948         if (mddev->bitmap_info.file)
1949                 len = sprintf(page, "file");
1950         else if (mddev->bitmap_info.offset)
1951                 len = sprintf(page, "%+lld", (long long)mddev->bitmap_info.offset);
1952         else
1953                 len = sprintf(page, "none");
1954         len += sprintf(page+len, "\n");
1955         return len;
1956 }
1957
1958 static ssize_t
1959 location_store(struct mddev *mddev, const char *buf, size_t len)
1960 {
1961
1962         if (mddev->pers) {
1963                 if (!mddev->pers->quiesce)
1964                         return -EBUSY;
1965                 if (mddev->recovery || mddev->sync_thread)
1966                         return -EBUSY;
1967         }
1968
1969         if (mddev->bitmap || mddev->bitmap_info.file ||
1970             mddev->bitmap_info.offset) {
1971                 /* bitmap already configured.  Only option is to clear it */
1972                 if (strncmp(buf, "none", 4) != 0)
1973                         return -EBUSY;
1974                 if (mddev->pers) {
1975                         mddev->pers->quiesce(mddev, 1);
1976                         bitmap_destroy(mddev);
1977                         mddev->pers->quiesce(mddev, 0);
1978                 }
1979                 mddev->bitmap_info.offset = 0;
1980                 if (mddev->bitmap_info.file) {
1981                         struct file *f = mddev->bitmap_info.file;
1982                         mddev->bitmap_info.file = NULL;
1983                         fput(f);
1984                 }
1985         } else {
1986                 /* No bitmap, OK to set a location */
1987                 long long offset;
1988                 if (strncmp(buf, "none", 4) == 0)
1989                         /* nothing to be done */;
1990                 else if (strncmp(buf, "file:", 5) == 0) {
1991                         /* Not supported yet */
1992                         return -EINVAL;
1993                 } else {
1994                         int rv;
1995                         if (buf[0] == '+')
1996                                 rv = kstrtoll(buf+1, 10, &offset);
1997                         else
1998                                 rv = kstrtoll(buf, 10, &offset);
1999                         if (rv)
2000                                 return rv;
2001                         if (offset == 0)
2002                                 return -EINVAL;
2003                         if (mddev->bitmap_info.external == 0 &&
2004                             mddev->major_version == 0 &&
2005                             offset != mddev->bitmap_info.default_offset)
2006                                 return -EINVAL;
2007                         mddev->bitmap_info.offset = offset;
2008                         if (mddev->pers) {
2009                                 mddev->pers->quiesce(mddev, 1);
2010                                 rv = bitmap_create(mddev);
2011                                 if (!rv)
2012                                         rv = bitmap_load(mddev);
2013                                 if (rv) {
2014                                         bitmap_destroy(mddev);
2015                                         mddev->bitmap_info.offset = 0;
2016                                 }
2017                                 mddev->pers->quiesce(mddev, 0);
2018                                 if (rv)
2019                                         return rv;
2020                         }
2021                 }
2022         }
2023         if (!mddev->external) {
2024                 /* Ensure new bitmap info is stored in
2025                  * metadata promptly.
2026                  */
2027                 set_bit(MD_CHANGE_DEVS, &mddev->flags);
2028                 md_wakeup_thread(mddev->thread);
2029         }
2030         return len;
2031 }
2032
2033 static struct md_sysfs_entry bitmap_location =
2034 __ATTR(location, S_IRUGO|S_IWUSR, location_show, location_store);
2035
2036 /* 'bitmap/space' is the space available at 'location' for the
2037  * bitmap.  This allows the kernel to know when it is safe to
2038  * resize the bitmap to match a resized array.
2039  */
2040 static ssize_t
2041 space_show(struct mddev *mddev, char *page)
2042 {
2043         return sprintf(page, "%lu\n", mddev->bitmap_info.space);
2044 }
2045
2046 static ssize_t
2047 space_store(struct mddev *mddev, const char *buf, size_t len)
2048 {
2049         unsigned long sectors;
2050         int rv;
2051
2052         rv = kstrtoul(buf, 10, &sectors);
2053         if (rv)
2054                 return rv;
2055
2056         if (sectors == 0)
2057                 return -EINVAL;
2058
2059         if (mddev->bitmap &&
2060             sectors < (mddev->bitmap->storage.bytes + 511) >> 9)
2061                 return -EFBIG; /* Bitmap is too big for this small space */
2062
2063         /* could make sure it isn't too big, but that isn't really
2064          * needed - user-space should be careful.
2065          */
2066         mddev->bitmap_info.space = sectors;
2067         return len;
2068 }
2069
2070 static struct md_sysfs_entry bitmap_space =
2071 __ATTR(space, S_IRUGO|S_IWUSR, space_show, space_store);
2072
2073 static ssize_t
2074 timeout_show(struct mddev *mddev, char *page)
2075 {
2076         ssize_t len;
2077         unsigned long secs = mddev->bitmap_info.daemon_sleep / HZ;
2078         unsigned long jifs = mddev->bitmap_info.daemon_sleep % HZ;
2079
2080         len = sprintf(page, "%lu", secs);
2081         if (jifs)
2082                 len += sprintf(page+len, ".%03u", jiffies_to_msecs(jifs));
2083         len += sprintf(page+len, "\n");
2084         return len;
2085 }
2086
2087 static ssize_t
2088 timeout_store(struct mddev *mddev, const char *buf, size_t len)
2089 {
2090         /* timeout can be set at any time */
2091         unsigned long timeout;
2092         int rv = strict_strtoul_scaled(buf, &timeout, 4);
2093         if (rv)
2094                 return rv;
2095
2096         /* just to make sure we don't overflow... */
2097         if (timeout >= LONG_MAX / HZ)
2098                 return -EINVAL;
2099
2100         timeout = timeout * HZ / 10000;
2101
2102         if (timeout >= MAX_SCHEDULE_TIMEOUT)
2103                 timeout = MAX_SCHEDULE_TIMEOUT-1;
2104         if (timeout < 1)
2105                 timeout = 1;
2106         mddev->bitmap_info.daemon_sleep = timeout;
2107         if (mddev->thread) {
2108                 /* if thread->timeout is MAX_SCHEDULE_TIMEOUT, then
2109                  * the bitmap is all clean and we don't need to
2110                  * adjust the timeout right now
2111                  */
2112                 if (mddev->thread->timeout < MAX_SCHEDULE_TIMEOUT) {
2113                         mddev->thread->timeout = timeout;
2114                         md_wakeup_thread(mddev->thread);
2115                 }
2116         }
2117         return len;
2118 }
2119
2120 static struct md_sysfs_entry bitmap_timeout =
2121 __ATTR(time_base, S_IRUGO|S_IWUSR, timeout_show, timeout_store);
2122
2123 static ssize_t
2124 backlog_show(struct mddev *mddev, char *page)
2125 {
2126         return sprintf(page, "%lu\n", mddev->bitmap_info.max_write_behind);
2127 }
2128
2129 static ssize_t
2130 backlog_store(struct mddev *mddev, const char *buf, size_t len)
2131 {
2132         unsigned long backlog;
2133         int rv = kstrtoul(buf, 10, &backlog);
2134         if (rv)
2135                 return rv;
2136         if (backlog > COUNTER_MAX)
2137                 return -EINVAL;
2138         mddev->bitmap_info.max_write_behind = backlog;
2139         return len;
2140 }
2141
2142 static struct md_sysfs_entry bitmap_backlog =
2143 __ATTR(backlog, S_IRUGO|S_IWUSR, backlog_show, backlog_store);
2144
2145 static ssize_t
2146 chunksize_show(struct mddev *mddev, char *page)
2147 {
2148         return sprintf(page, "%lu\n", mddev->bitmap_info.chunksize);
2149 }
2150
2151 static ssize_t
2152 chunksize_store(struct mddev *mddev, const char *buf, size_t len)
2153 {
2154         /* Can only be changed when no bitmap is active */
2155         int rv;
2156         unsigned long csize;
2157         if (mddev->bitmap)
2158                 return -EBUSY;
2159         rv = kstrtoul(buf, 10, &csize);
2160         if (rv)
2161                 return rv;
2162         if (csize < 512 ||
2163             !is_power_of_2(csize))
2164                 return -EINVAL;
2165         mddev->bitmap_info.chunksize = csize;
2166         return len;
2167 }
2168
2169 static struct md_sysfs_entry bitmap_chunksize =
2170 __ATTR(chunksize, S_IRUGO|S_IWUSR, chunksize_show, chunksize_store);
2171
2172 static ssize_t metadata_show(struct mddev *mddev, char *page)
2173 {
2174         return sprintf(page, "%s\n", (mddev->bitmap_info.external
2175                                       ? "external" : "internal"));
2176 }
2177
2178 static ssize_t metadata_store(struct mddev *mddev, const char *buf, size_t len)
2179 {
2180         if (mddev->bitmap ||
2181             mddev->bitmap_info.file ||
2182             mddev->bitmap_info.offset)
2183                 return -EBUSY;
2184         if (strncmp(buf, "external", 8) == 0)
2185                 mddev->bitmap_info.external = 1;
2186         else if (strncmp(buf, "internal", 8) == 0)
2187                 mddev->bitmap_info.external = 0;
2188         else
2189                 return -EINVAL;
2190         return len;
2191 }
2192
2193 static struct md_sysfs_entry bitmap_metadata =
2194 __ATTR(metadata, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
2195
2196 static ssize_t can_clear_show(struct mddev *mddev, char *page)
2197 {
2198         int len;
2199         if (mddev->bitmap)
2200                 len = sprintf(page, "%s\n", (mddev->bitmap->need_sync ?
2201                                              "false" : "true"));
2202         else
2203                 len = sprintf(page, "\n");
2204         return len;
2205 }
2206
2207 static ssize_t can_clear_store(struct mddev *mddev, const char *buf, size_t len)
2208 {
2209         if (mddev->bitmap == NULL)
2210                 return -ENOENT;
2211         if (strncmp(buf, "false", 5) == 0)
2212                 mddev->bitmap->need_sync = 1;
2213         else if (strncmp(buf, "true", 4) == 0) {
2214                 if (mddev->degraded)
2215                         return -EBUSY;
2216                 mddev->bitmap->need_sync = 0;
2217         } else
2218                 return -EINVAL;
2219         return len;
2220 }
2221
2222 static struct md_sysfs_entry bitmap_can_clear =
2223 __ATTR(can_clear, S_IRUGO|S_IWUSR, can_clear_show, can_clear_store);
2224
2225 static ssize_t
2226 behind_writes_used_show(struct mddev *mddev, char *page)
2227 {
2228         if (mddev->bitmap == NULL)
2229                 return sprintf(page, "0\n");
2230         return sprintf(page, "%lu\n",
2231                        mddev->bitmap->behind_writes_used);
2232 }
2233
2234 static ssize_t
2235 behind_writes_used_reset(struct mddev *mddev, const char *buf, size_t len)
2236 {
2237         if (mddev->bitmap)
2238                 mddev->bitmap->behind_writes_used = 0;
2239         return len;
2240 }
2241
2242 static struct md_sysfs_entry max_backlog_used =
2243 __ATTR(max_backlog_used, S_IRUGO | S_IWUSR,
2244        behind_writes_used_show, behind_writes_used_reset);
2245
2246 static struct attribute *md_bitmap_attrs[] = {
2247         &bitmap_location.attr,
2248         &bitmap_space.attr,
2249         &bitmap_timeout.attr,
2250         &bitmap_backlog.attr,
2251         &bitmap_chunksize.attr,
2252         &bitmap_metadata.attr,
2253         &bitmap_can_clear.attr,
2254         &max_backlog_used.attr,
2255         NULL
2256 };
2257 struct attribute_group md_bitmap_group = {
2258         .name = "bitmap",
2259         .attrs = md_bitmap_attrs,
2260 };
2261