drivers/md/bitmap.c

   1 /*
   2  * bitmap.c two-level bitmap (C) Peter T. Breuer (ptb@ot.uc3m.es) 2003
   3  *
   4  * bitmap_create  - sets up the bitmap structure
   5  * bitmap_destroy - destroys the bitmap structure
   6  *
   7  * additions, Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.:
   8  * - added disk storage for bitmap
   9  * - changes to allow various bitmap chunk sizes
  10  */
  11
  12 /*
  13  * Still to do:
  14  *
  15  * flush after percent set rather than just time based. (maybe both).
  16  */
  17
  18 #include <linux/blkdev.h>
  19 #include <linux/module.h>
  20 #include <linux/errno.h>
  21 #include <linux/slab.h>
  22 #include <linux/init.h>
  23 #include <linux/timer.h>
  24 #include <linux/sched.h>
  25 #include <linux/list.h>
  26 #include <linux/file.h>
  27 #include <linux/mount.h>
  28 #include <linux/buffer_head.h>
  29 #include "md.h"
  30 #include "bitmap.h"
  31
  32 static inline char *bmname(struct bitmap *bitmap)
  33 {
  34         return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
  35 }
  36
  37 /*
  38  * just a placeholder - calls kmalloc for bitmap pages
  39  */
  40 static unsigned char *bitmap_alloc_page(struct bitmap *bitmap)
  41 {
  42         unsigned char *page;
  43
  44         page = kzalloc(PAGE_SIZE, GFP_NOIO);
  45         if (!page)
  46                 printk("%s: bitmap_alloc_page FAILED\n", bmname(bitmap));
  47         else
  48                 pr_debug("%s: bitmap_alloc_page: allocated page at %p\n",
  49                          bmname(bitmap), page);
  50         return page;
  51 }
  52
  53 /*
  54  * for now just a placeholder -- just calls kfree for bitmap pages
  55  */
  56 static void bitmap_free_page(struct bitmap *bitmap, unsigned char *page)
  57 {
  58         pr_debug("%s: bitmap_free_page: free page %p\n", bmname(bitmap), page);
  59         kfree(page);
  60 }
  61
  62 /*
  63  * check a page and, if necessary, allocate it (or hijack it if the alloc fails)
  64  *
  65  * 1) check to see if this page is allocated, if it's not then try to alloc
  66  * 2) if the alloc fails, set the page's hijacked flag so we'll use the
  67  *    page pointer directly as a counter
  68  *
  69  * if we find our page, we increment the page's refcount so that it stays
  70  * allocated while we're using it
  71  */
  72 static int bitmap_checkpage(struct bitmap *bitmap,
  73                             unsigned long page, int create)
  74 __releases(bitmap->lock)
  75 __acquires(bitmap->lock)
  76 {
  77         unsigned char *mappage;
  78
  79         if (page >= bitmap->pages) {
  80                 /* This can happen if bitmap_start_sync goes beyond
  81                  * End-of-device while looking for a whole page.
  82                  * It is harmless.
  83                  */
  84                 return -EINVAL;
  85         }
  86
  87         if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
  88                 return 0;
  89
  90         if (bitmap->bp[page].map) /* page is already allocated, just return */
  91                 return 0;
  92
  93         if (!create)
  94                 return -ENOENT;
  95
  96         /* this page has not been allocated yet */
  97
  98         spin_unlock_irq(&bitmap->lock);
  99         mappage = bitmap_alloc_page(bitmap);
 100         spin_lock_irq(&bitmap->lock);
 101
 102         if (mappage == NULL) {
 103                 pr_debug("%s: bitmap map page allocation failed, hijacking\n",
 104                          bmname(bitmap));
 105                 /* failed - set the hijacked flag so that we can use the
 106                  * pointer as a counter */
 107                 if (!bitmap->bp[page].map)
 108                         bitmap->bp[page].hijacked = 1;
 109         } else if (bitmap->bp[page].map ||
 110                    bitmap->bp[page].hijacked) {
 111                 /* somebody beat us to getting the page */
 112                 bitmap_free_page(bitmap, mappage);
 113                 return 0;
 114         } else {
 115
 116                 /* no page was in place and we have one, so install it */
 117
 118                 bitmap->bp[page].map = mappage;
 119                 bitmap->missing_pages--;
 120         }
 121         return 0;
 122 }
 123
 124 /* if page is completely empty, put it back on the free list, or dealloc it */
 125 /* if page was hijacked, unmark the flag so it might get alloced next time */
 126 /* Note: lock should be held when calling this */
 127 static void bitmap_checkfree(struct bitmap *bitmap, unsigned long page)
 128 {
 129         char *ptr;
 130
 131         if (bitmap->bp[page].count) /* page is still busy */
 132                 return;
 133
 134         /* page is no longer in use, it can be released */
 135
 136         if (bitmap->bp[page].hijacked) { /* page was hijacked, undo this now */
 137                 bitmap->bp[page].hijacked = 0;
 138                 bitmap->bp[page].map = NULL;
 139         } else {
 140                 /* normal case, free the page */
 141                 ptr = bitmap->bp[page].map;
 142                 bitmap->bp[page].map = NULL;
 143                 bitmap->missing_pages++;
 144                 bitmap_free_page(bitmap, ptr);
 145         }
 146 }
 147
 148 /*
 149  * bitmap file handling - read and write the bitmap file and its superblock
 150  */
 151
 152 /*
 153  * basic page I/O operations
 154  */
 155
 156 /* IO operations when bitmap is stored near all superblocks */
 157 static struct page *read_sb_page(struct mddev *mddev, loff_t offset,
 158                                  struct page *page,
 159                                  unsigned long index, int size)
 160 {
 161         /* choose a good rdev and read the page from there */
 162
 163         struct md_rdev *rdev;
 164         sector_t target;
 165         int did_alloc = 0;
 166
 167         if (!page) {
 168                 page = alloc_page(GFP_KERNEL);
 169                 if (!page)
 170                         return ERR_PTR(-ENOMEM);
 171                 did_alloc = 1;
 172         }
 173
 174         list_for_each_entry(rdev, &mddev->disks, same_set) {
 175                 if (! test_bit(In_sync, &rdev->flags)
 176                     || test_bit(Faulty, &rdev->flags))
 177                         continue;
 178
 179                 target = offset + index * (PAGE_SIZE/512);
 180
 181                 if (sync_page_io(rdev, target,
 182                                  roundup(size, bdev_logical_block_size(rdev->bdev)),
 183                                  page, READ, true)) {
 184                         page->index = index;
 185                         attach_page_buffers(page, NULL); /* so that free_buffer will
 186                                                           * quietly no-op */
 187                         return page;
 188                 }
 189         }
 190         if (did_alloc)
 191                 put_page(page);
 192         return ERR_PTR(-EIO);
 193
 194 }
 195
 196 static struct md_rdev *next_active_rdev(struct md_rdev *rdev, struct mddev *mddev)
 197 {
 198         /* Iterate the disks of an mddev, using rcu to protect access to the
 199          * linked list, and raising the refcount of devices we return to ensure
 200          * they don't disappear while in use.
 201          * As devices are only added or removed when raid_disk is < 0 and
 202          * nr_pending is 0 and In_sync is clear, the entries we return will
 203          * still be in the same position on the list when we re-enter
 204          * list_for_each_continue_rcu.
 205          */
 206         struct list_head *pos;
 207         rcu_read_lock();
 208         if (rdev == NULL)
 209                 /* start at the beginning */
 210                 pos = &mddev->disks;
 211         else {
 212                 /* release the previous rdev and start from there. */
 213                 rdev_dec_pending(rdev, mddev);
 214                 pos = &rdev->same_set;
 215         }
 216         list_for_each_continue_rcu(pos, &mddev->disks) {
 217                 rdev = list_entry(pos, struct md_rdev, same_set);
 218                 if (rdev->raid_disk >= 0 &&
 219                     !test_bit(Faulty, &rdev->flags)) {
 220                         /* this is a usable devices */
 221                         atomic_inc(&rdev->nr_pending);
 222                         rcu_read_unlock();
 223                         return rdev;
 224                 }
 225         }
 226         rcu_read_unlock();
 227         return NULL;
 228 }
 229
 230 static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
 231 {
 232         struct md_rdev *rdev = NULL;
 233         struct block_device *bdev;
 234         struct mddev *mddev = bitmap->mddev;
 235
 236         while ((rdev = next_active_rdev(rdev, mddev)) != NULL) {
 237                 int size = PAGE_SIZE;
 238                 loff_t offset = mddev->bitmap_info.offset;
 239
 240                 bdev = (rdev->meta_bdev) ? rdev->meta_bdev : rdev->bdev;
 241
 242                 if (page->index == bitmap->file_pages-1)
 243                         size = roundup(bitmap->last_page_size,
 244                                        bdev_logical_block_size(bdev));
 245                 /* Just make sure we aren't corrupting data or
 246                  * metadata
 247                  */
 248                 if (mddev->external) {
 249                         /* Bitmap could be anywhere. */
 250                         if (rdev->sb_start + offset + (page->index
 251                                                        * (PAGE_SIZE/512))
 252                             > rdev->data_offset
 253                             &&
 254                             rdev->sb_start + offset
 255                             < (rdev->data_offset + mddev->dev_sectors
 256                              + (PAGE_SIZE/512)))
 257                                 goto bad_alignment;
 258                 } else if (offset < 0) {
 259                         /* DATA  BITMAP METADATA  */
 260                         if (offset
 261                             + (long)(page->index * (PAGE_SIZE/512))
 262                             + size/512 > 0)
 263                                 /* bitmap runs in to metadata */
 264                                 goto bad_alignment;
 265                         if (rdev->data_offset + mddev->dev_sectors
 266                             > rdev->sb_start + offset)
 267                                 /* data runs in to bitmap */
 268                                 goto bad_alignment;
 269                 } else if (rdev->sb_start < rdev->data_offset) {
 270                         /* METADATA BITMAP DATA */
 271                         if (rdev->sb_start
 272                             + offset
 273                             + page->index*(PAGE_SIZE/512) + size/512
 274                             > rdev->data_offset)
 275                                 /* bitmap runs in to data */
 276                                 goto bad_alignment;
 277                 } else {
 278                         /* DATA METADATA BITMAP - no problems */
 279                 }
 280                 md_super_write(mddev, rdev,
 281                                rdev->sb_start + offset
 282                                + page->index * (PAGE_SIZE/512),
 283                                size,
 284                                page);
 285         }
 286
 287         if (wait)
 288                 md_super_wait(mddev);
 289         return 0;
 290
 291  bad_alignment:
 292         return -EINVAL;
 293 }
 294
 295 static void bitmap_file_kick(struct bitmap *bitmap);
 296 /*
 297  * write out a page to a file
 298  */
 299 static void write_page(struct bitmap *bitmap, struct page *page, int wait)
 300 {
 301         struct buffer_head *bh;
 302
 303         if (bitmap->file == NULL) {
 304                 switch (write_sb_page(bitmap, page, wait)) {
 305                 case -EINVAL:
 306                         bitmap->flags |= BITMAP_WRITE_ERROR;
 307                 }
 308         } else {
 309
 310                 bh = page_buffers(page);
 311
 312                 while (bh && bh->b_blocknr) {
 313                         atomic_inc(&bitmap->pending_writes);
 314                         set_buffer_locked(bh);
 315                         set_buffer_mapped(bh);
 316                         submit_bh(WRITE | REQ_SYNC, bh);
 317                         bh = bh->b_this_page;
 318                 }
 319
 320                 if (wait)
 321                         wait_event(bitmap->write_wait,
 322                                    atomic_read(&bitmap->pending_writes)==0);
 323         }
 324         if (bitmap->flags & BITMAP_WRITE_ERROR)
 325                 bitmap_file_kick(bitmap);
 326 }
 327
 328 static void end_bitmap_write(struct buffer_head *bh, int uptodate)
 329 {
 330         struct bitmap *bitmap = bh->b_private;
 331         unsigned long flags;
 332
 333         if (!uptodate) {
 334                 spin_lock_irqsave(&bitmap->lock, flags);
 335                 bitmap->flags |= BITMAP_WRITE_ERROR;
 336                 spin_unlock_irqrestore(&bitmap->lock, flags);
 337         }
 338         if (atomic_dec_and_test(&bitmap->pending_writes))
 339                 wake_up(&bitmap->write_wait);
 340 }
 341
 342 /* copied from buffer.c */
 343 static void
 344 __clear_page_buffers(struct page *page)
 345 {
 346         ClearPagePrivate(page);
 347         set_page_private(page, 0);
 348         page_cache_release(page);
 349 }
 350 static void free_buffers(struct page *page)
 351 {
 352         struct buffer_head *bh = page_buffers(page);
 353
 354         while (bh) {
 355                 struct buffer_head *next = bh->b_this_page;
 356                 free_buffer_head(bh);
 357                 bh = next;
 358         }
 359         __clear_page_buffers(page);
 360         put_page(page);
 361 }
 362
 363 /* read a page from a file.
 364  * We both read the page, and attach buffers to the page to record the
 365  * address of each block (using bmap).  These addresses will be used
 366  * to write the block later, completely bypassing the filesystem.
 367  * This usage is similar to how swap files are handled, and allows us
 368  * to write to a file with no concerns of memory allocation failing.
 369  */
 370 static struct page *read_page(struct file *file, unsigned long index,
 371                               struct bitmap *bitmap,
 372                               unsigned long count)
 373 {
 374         struct page *page = NULL;
 375         struct inode *inode = file->f_path.dentry->d_inode;
 376         struct buffer_head *bh;
 377         sector_t block;
 378
 379         pr_debug("read bitmap file (%dB @ %llu)\n", (int)PAGE_SIZE,
 380                  (unsigned long long)index << PAGE_SHIFT);
 381
 382         page = alloc_page(GFP_KERNEL);
 383         if (!page)
 384                 page = ERR_PTR(-ENOMEM);
 385         if (IS_ERR(page))
 386                 goto out;
 387
 388         bh = alloc_page_buffers(page, 1<<inode->i_blkbits, 0);
 389         if (!bh) {
 390                 put_page(page);
 391                 page = ERR_PTR(-ENOMEM);
 392                 goto out;
 393         }
 394         attach_page_buffers(page, bh);
 395         block = index << (PAGE_SHIFT - inode->i_blkbits);
 396         while (bh) {
 397                 if (count == 0)
 398                         bh->b_blocknr = 0;
 399                 else {
 400                         bh->b_blocknr = bmap(inode, block);
 401                         if (bh->b_blocknr == 0) {
 402                                 /* Cannot use this file! */
 403                                 free_buffers(page);
 404                                 page = ERR_PTR(-EINVAL);
 405                                 goto out;
 406                         }
 407                         bh->b_bdev = inode->i_sb->s_bdev;
 408                         if (count < (1<<inode->i_blkbits))
 409                                 count = 0;
 410                         else
 411                                 count -= (1<<inode->i_blkbits);
 412
 413                         bh->b_end_io = end_bitmap_write;
 414                         bh->b_private = bitmap;
 415                         atomic_inc(&bitmap->pending_writes);
 416                         set_buffer_locked(bh);
 417                         set_buffer_mapped(bh);
 418                         submit_bh(READ, bh);
 419                 }
 420                 block++;
 421                 bh = bh->b_this_page;
 422         }
 423         page->index = index;
 424
 425         wait_event(bitmap->write_wait,
 426                    atomic_read(&bitmap->pending_writes)==0);
 427         if (bitmap->flags & BITMAP_WRITE_ERROR) {
 428                 free_buffers(page);
 429                 page = ERR_PTR(-EIO);
 430         }
 431 out:
 432         if (IS_ERR(page))
 433                 printk(KERN_ALERT "md: bitmap read error: (%dB @ %llu): %ld\n",
 434                         (int)PAGE_SIZE,
 435                         (unsigned long long)index << PAGE_SHIFT,
 436                         PTR_ERR(page));
 437         return page;
 438 }
 439
 440 /*
 441  * bitmap file superblock operations
 442  */
 443
 444 /* update the event counter and sync the superblock to disk */
 445 void bitmap_update_sb(struct bitmap *bitmap)
 446 {
 447         bitmap_super_t *sb;
 448         unsigned long flags;
 449
 450         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
 451                 return;
 452         if (bitmap->mddev->bitmap_info.external)
 453                 return;
 454         spin_lock_irqsave(&bitmap->lock, flags);
 455         if (!bitmap->sb_page) { /* no superblock */
 456                 spin_unlock_irqrestore(&bitmap->lock, flags);
 457                 return;
 458         }
 459         spin_unlock_irqrestore(&bitmap->lock, flags);
 460         sb = kmap_atomic(bitmap->sb_page, KM_USER0);
 461         sb->events = cpu_to_le64(bitmap->mddev->events);
 462         if (bitmap->mddev->events < bitmap->events_cleared)
 463                 /* rocking back to read-only */
 464                 bitmap->events_cleared = bitmap->mddev->events;
 465         sb->events_cleared = cpu_to_le64(bitmap->events_cleared);
 466         sb->state = cpu_to_le32(bitmap->flags);
 467         /* Just in case these have been changed via sysfs: */
 468         sb->daemon_sleep = cpu_to_le32(bitmap->mddev->bitmap_info.daemon_sleep/HZ);
 469         sb->write_behind = cpu_to_le32(bitmap->mddev->bitmap_info.max_write_behind);
 470         kunmap_atomic(sb, KM_USER0);
 471         write_page(bitmap, bitmap->sb_page, 1);
 472 }
 473
 474 /* print out the bitmap file superblock */
 475 void bitmap_print_sb(struct bitmap *bitmap)
 476 {
 477         bitmap_super_t *sb;
 478
 479         if (!bitmap || !bitmap->sb_page)
 480                 return;
 481         sb = kmap_atomic(bitmap->sb_page, KM_USER0);
 482         printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
 483         printk(KERN_DEBUG "         magic: %08x\n", le32_to_cpu(sb->magic));
 484         printk(KERN_DEBUG "       version: %d\n", le32_to_cpu(sb->version));
 485         printk(KERN_DEBUG "          uuid: %08x.%08x.%08x.%08x\n",
 486                                         *(__u32 *)(sb->uuid+0),
 487                                         *(__u32 *)(sb->uuid+4),
 488                                         *(__u32 *)(sb->uuid+8),
 489                                         *(__u32 *)(sb->uuid+12));
 490         printk(KERN_DEBUG "        events: %llu\n",
 491                         (unsigned long long) le64_to_cpu(sb->events));
 492         printk(KERN_DEBUG "events cleared: %llu\n",
 493                         (unsigned long long) le64_to_cpu(sb->events_cleared));
 494         printk(KERN_DEBUG "         state: %08x\n", le32_to_cpu(sb->state));
 495         printk(KERN_DEBUG "     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
 496         printk(KERN_DEBUG "  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
 497         printk(KERN_DEBUG "     sync size: %llu KB\n",
 498                         (unsigned long long)le64_to_cpu(sb->sync_size)/2);
 499         printk(KERN_DEBUG "max write behind: %d\n", le32_to_cpu(sb->write_behind));
 500         kunmap_atomic(sb, KM_USER0);
 501 }
 502
 503 /*
 504  * bitmap_new_disk_sb
 505  * @bitmap
 506  *
 507  * This function is somewhat the reverse of bitmap_read_sb.  bitmap_read_sb
 508  * reads and verifies the on-disk bitmap superblock and populates bitmap_info.
 509  * This function verifies 'bitmap_info' and populates the on-disk bitmap
 510  * structure, which is to be written to disk.
 511  *
 512  * Returns: 0 on success, -Exxx on error
 513  */
 514 static int bitmap_new_disk_sb(struct bitmap *bitmap)
 515 {
 516         bitmap_super_t *sb;
 517         unsigned long chunksize, daemon_sleep, write_behind;
 518         int err = -EINVAL;
 519
 520         bitmap->sb_page = alloc_page(GFP_KERNEL);
 521         if (IS_ERR(bitmap->sb_page)) {
 522                 err = PTR_ERR(bitmap->sb_page);
 523                 bitmap->sb_page = NULL;
 524                 return err;
 525         }
 526         bitmap->sb_page->index = 0;
 527
 528         sb = kmap_atomic(bitmap->sb_page, KM_USER0);
 529
 530         sb->magic = cpu_to_le32(BITMAP_MAGIC);
 531         sb->version = cpu_to_le32(BITMAP_MAJOR_HI);
 532
 533         chunksize = bitmap->mddev->bitmap_info.chunksize;
 534         BUG_ON(!chunksize);
 535         if (!is_power_of_2(chunksize)) {
 536                 kunmap_atomic(sb, KM_USER0);
 537                 printk(KERN_ERR "bitmap chunksize not a power of 2\n");
 538                 return -EINVAL;
 539         }
 540         sb->chunksize = cpu_to_le32(chunksize);
 541
 542         daemon_sleep = bitmap->mddev->bitmap_info.daemon_sleep;
 543         if (!daemon_sleep ||
 544             (daemon_sleep < 1) || (daemon_sleep > MAX_SCHEDULE_TIMEOUT)) {
 545                 printk(KERN_INFO "Choosing daemon_sleep default (5 sec)\n");
 546                 daemon_sleep = 5 * HZ;
 547         }
 548         sb->daemon_sleep = cpu_to_le32(daemon_sleep);
 549         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 550
 551         /*
 552          * FIXME: write_behind for RAID1.  If not specified, what
 553          * is a good choice?  We choose COUNTER_MAX / 2 arbitrarily.
 554          */
 555         write_behind = bitmap->mddev->bitmap_info.max_write_behind;
 556         if (write_behind > COUNTER_MAX)
 557                 write_behind = COUNTER_MAX / 2;
 558         sb->write_behind = cpu_to_le32(write_behind);
 559         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 560
 561         /* keep the array size field of the bitmap superblock up to date */
 562         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 563
 564         memcpy(sb->uuid, bitmap->mddev->uuid, 16);
 565
 566         bitmap->flags |= BITMAP_STALE;
 567         sb->state |= cpu_to_le32(BITMAP_STALE);
 568         bitmap->events_cleared = bitmap->mddev->events;
 569         sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
 570
 571         bitmap->flags |= BITMAP_HOSTENDIAN;
 572         sb->version = cpu_to_le32(BITMAP_MAJOR_HOSTENDIAN);
 573
 574         kunmap_atomic(sb, KM_USER0);
 575
 576         return 0;
 577 }
 578
 579 /* read the superblock from the bitmap file and initialize some bitmap fields */
 580 static int bitmap_read_sb(struct bitmap *bitmap)
 581 {
 582         char *reason = NULL;
 583         bitmap_super_t *sb;
 584         unsigned long chunksize, daemon_sleep, write_behind;
 585         unsigned long long events;
 586         int err = -EINVAL;
 587
 588         /* page 0 is the superblock, read it... */
 589         if (bitmap->file) {
 590                 loff_t isize = i_size_read(bitmap->file->f_mapping->host);
 591                 int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
 592
 593                 bitmap->sb_page = read_page(bitmap->file, 0, bitmap, bytes);
 594         } else {
 595                 bitmap->sb_page = read_sb_page(bitmap->mddev,
 596                                                bitmap->mddev->bitmap_info.offset,
 597                                                NULL,
 598                                                0, sizeof(bitmap_super_t));
 599         }
 600         if (IS_ERR(bitmap->sb_page)) {
 601                 err = PTR_ERR(bitmap->sb_page);
 602                 bitmap->sb_page = NULL;
 603                 return err;
 604         }
 605
 606         sb = kmap_atomic(bitmap->sb_page, KM_USER0);
 607
 608         chunksize = le32_to_cpu(sb->chunksize);
 609         daemon_sleep = le32_to_cpu(sb->daemon_sleep) * HZ;
 610         write_behind = le32_to_cpu(sb->write_behind);
 611
 612         /* verify that the bitmap-specific fields are valid */
 613         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
 614                 reason = "bad magic";
 615         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
 616                  le32_to_cpu(sb->version) > BITMAP_MAJOR_HI)
 617                 reason = "unrecognized superblock version";
 618         else if (chunksize < 512)
 619                 reason = "bitmap chunksize too small";
 620         else if (!is_power_of_2(chunksize))
 621                 reason = "bitmap chunksize not a power of 2";
 622         else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT)
 623                 reason = "daemon sleep period out of range";
 624         else if (write_behind > COUNTER_MAX)
 625                 reason = "write-behind limit out of range (0 - 16383)";
 626         if (reason) {
 627                 printk(KERN_INFO "%s: invalid bitmap file superblock: %s\n",
 628                         bmname(bitmap), reason);
 629                 goto out;
 630         }
 631
 632         /* keep the array size field of the bitmap superblock up to date */
 633         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 634
 635         if (!bitmap->mddev->persistent)
 636                 goto success;
 637
 638         /*
 639          * if we have a persistent array superblock, compare the
 640          * bitmap's UUID and event counter to the mddev's
 641          */
 642         if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
 643                 printk(KERN_INFO "%s: bitmap superblock UUID mismatch\n",
 644                         bmname(bitmap));
 645                 goto out;
 646         }
 647         events = le64_to_cpu(sb->events);
 648         if (events < bitmap->mddev->events) {
 649                 printk(KERN_INFO "%s: bitmap file is out of date (%llu < %llu) "
 650                         "-- forcing full recovery\n", bmname(bitmap), events,
 651                         (unsigned long long) bitmap->mddev->events);
 652                 sb->state |= cpu_to_le32(BITMAP_STALE);
 653         }
 654 success:
 655         /* assign fields using values from superblock */
 656         bitmap->mddev->bitmap_info.chunksize = chunksize;
 657         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 658         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 659         bitmap->flags |= le32_to_cpu(sb->state);
 660         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
 661                 bitmap->flags |= BITMAP_HOSTENDIAN;
 662         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
 663         if (bitmap->flags & BITMAP_STALE)
 664                 bitmap->events_cleared = bitmap->mddev->events;
 665         err = 0;
 666 out:
 667         kunmap_atomic(sb, KM_USER0);
 668         if (err)
 669                 bitmap_print_sb(bitmap);
 670         return err;
 671 }
 672
 673 enum bitmap_mask_op {
 674         MASK_SET,
 675         MASK_UNSET
 676 };
 677
 678 /* record the state of the bitmap in the superblock.  Return the old value */
 679 static int bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
 680                              enum bitmap_mask_op op)
 681 {
 682         bitmap_super_t *sb;
 683         unsigned long flags;
 684         int old;
 685
 686         spin_lock_irqsave(&bitmap->lock, flags);
 687         if (!bitmap->sb_page) { /* can't set the state */
 688                 spin_unlock_irqrestore(&bitmap->lock, flags);
 689                 return 0;
 690         }
 691         spin_unlock_irqrestore(&bitmap->lock, flags);
 692         sb = kmap_atomic(bitmap->sb_page, KM_USER0);
 693         old = le32_to_cpu(sb->state) & bits;
 694         switch (op) {
 695         case MASK_SET:
 696                 sb->state |= cpu_to_le32(bits);
 697                 bitmap->flags |= bits;
 698                 break;
 699         case MASK_UNSET:
 700                 sb->state &= cpu_to_le32(~bits);
 701                 bitmap->flags &= ~bits;
 702                 break;
 703         default:
 704                 BUG();
 705         }
 706         kunmap_atomic(sb, KM_USER0);
 707         return old;
 708 }
 709
 710 /*
 711  * general bitmap file operations
 712  */
 713
 714 /*
 715  * on-disk bitmap:
 716  *
 717  * Use one bit per "chunk" (block set). We do the disk I/O on the bitmap
 718  * file a page at a time. There's a superblock at the start of the file.
 719  */
 720 /* calculate the index of the page that contains this bit */
 721 static inline unsigned long file_page_index(struct bitmap *bitmap, unsigned long chunk)
 722 {
 723         if (!bitmap->mddev->bitmap_info.external)
 724                 chunk += sizeof(bitmap_super_t) << 3;
 725         return chunk >> PAGE_BIT_SHIFT;
 726 }
 727
 728 /* calculate the (bit) offset of this bit within a page */
 729 static inline unsigned long file_page_offset(struct bitmap *bitmap, unsigned long chunk)
 730 {
 731         if (!bitmap->mddev->bitmap_info.external)
 732                 chunk += sizeof(bitmap_super_t) << 3;
 733         return chunk & (PAGE_BITS - 1);
 734 }
 735
 736 /*
 737  * return a pointer to the page in the filemap that contains the given bit
 738  *
 739  * this lookup is complicated by the fact that the bitmap sb might be exactly
 740  * 1 page (e.g., x86) or less than 1 page -- so the bitmap might start on page
 741  * 0 or page 1
 742  */
 743 static inline struct page *filemap_get_page(struct bitmap *bitmap,
 744                                             unsigned long chunk)
 745 {
 746         if (file_page_index(bitmap, chunk) >= bitmap->file_pages)
 747                 return NULL;
 748         return bitmap->filemap[file_page_index(bitmap, chunk)
 749                                - file_page_index(bitmap, 0)];
 750 }
 751
 752 static void bitmap_file_unmap(struct bitmap *bitmap)
 753 {
 754         struct page **map, *sb_page;
 755         unsigned long *attr;
 756         int pages;
 757         unsigned long flags;
 758
 759         spin_lock_irqsave(&bitmap->lock, flags);
 760         map = bitmap->filemap;
 761         bitmap->filemap = NULL;
 762         attr = bitmap->filemap_attr;
 763         bitmap->filemap_attr = NULL;
 764         pages = bitmap->file_pages;
 765         bitmap->file_pages = 0;
 766         sb_page = bitmap->sb_page;
 767         bitmap->sb_page = NULL;
 768         spin_unlock_irqrestore(&bitmap->lock, flags);
 769
 770         while (pages--)
 771                 if (map[pages] != sb_page) /* 0 is sb_page, release it below */
 772                         free_buffers(map[pages]);
 773         kfree(map);
 774         kfree(attr);
 775
 776         if (sb_page)
 777                 free_buffers(sb_page);
 778 }
 779
 780 static void bitmap_file_put(struct bitmap *bitmap)
 781 {
 782         struct file *file;
 783         unsigned long flags;
 784
 785         spin_lock_irqsave(&bitmap->lock, flags);
 786         file = bitmap->file;
 787         bitmap->file = NULL;
 788         spin_unlock_irqrestore(&bitmap->lock, flags);
 789
 790         if (file)
 791                 wait_event(bitmap->write_wait,
 792                            atomic_read(&bitmap->pending_writes)==0);
 793         bitmap_file_unmap(bitmap);
 794
 795         if (file) {
 796                 struct inode *inode = file->f_path.dentry->d_inode;
 797                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
 798                 fput(file);
 799         }
 800 }
 801
 802 /*
 803  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
 804  * then it is no longer reliable, so we stop using it and we mark the file
 805  * as failed in the superblock
 806  */
 807 static void bitmap_file_kick(struct bitmap *bitmap)
 808 {
 809         char *path, *ptr = NULL;
 810
 811         if (bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET) == 0) {
 812                 bitmap_update_sb(bitmap);
 813
 814                 if (bitmap->file) {
 815                         path = kmalloc(PAGE_SIZE, GFP_KERNEL);
 816                         if (path)
 817                                 ptr = d_path(&bitmap->file->f_path, path,
 818                                              PAGE_SIZE);
 819
 820                         printk(KERN_ALERT
 821                               "%s: kicking failed bitmap file %s from array!\n",
 822                               bmname(bitmap), IS_ERR(ptr) ? "" : ptr);
 823
 824                         kfree(path);
 825                 } else
 826                         printk(KERN_ALERT
 827                                "%s: disabling internal bitmap due to errors\n",
 828                                bmname(bitmap));
 829         }
 830
 831         bitmap_file_put(bitmap);
 832
 833         return;
 834 }
 835
 836 enum bitmap_page_attr {
 837         BITMAP_PAGE_DIRTY = 0,     /* there are set bits that need to be synced */
 838         BITMAP_PAGE_PENDING = 1,   /* there are bits that are being cleaned.
 839                                     * i.e. counter is 1 or 2. */
 840         BITMAP_PAGE_NEEDWRITE = 2, /* there are cleared bits that need to be synced */
 841 };
 842
 843 static inline void set_page_attr(struct bitmap *bitmap, struct page *page,
 844                                 enum bitmap_page_attr attr)
 845 {
 846         __set_bit((page->index<<2) + attr, bitmap->filemap_attr);
 847 }
 848
 849 static inline void clear_page_attr(struct bitmap *bitmap, struct page *page,
 850                                 enum bitmap_page_attr attr)
 851 {
 852         __clear_bit((page->index<<2) + attr, bitmap->filemap_attr);
 853 }
 854
 855 static inline unsigned long test_page_attr(struct bitmap *bitmap, struct page *page,
 856                                            enum bitmap_page_attr attr)
 857 {
 858         return test_bit((page->index<<2) + attr, bitmap->filemap_attr);
 859 }
 860
 861 /*
 862  * bitmap_file_set_bit -- called before performing a write to the md device
 863  * to set (and eventually sync) a particular bit in the bitmap file
 864  *
 865  * we set the bit immediately, then we record the page number so that
 866  * when an unplug occurs, we can flush the dirty pages out to disk
 867  */
 868 static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 869 {
 870         unsigned long bit;
 871         struct page *page;
 872         void *kaddr;
 873         unsigned long chunk = block >> CHUNK_BLOCK_SHIFT(bitmap);
 874
 875         if (!bitmap->filemap)
 876                 return;
 877
 878         page = filemap_get_page(bitmap, chunk);
 879         if (!page)
 880                 return;
 881         bit = file_page_offset(bitmap, chunk);
 882
 883         /* set the bit */
 884         kaddr = kmap_atomic(page, KM_USER0);
 885         if (bitmap->flags & BITMAP_HOSTENDIAN)
 886                 set_bit(bit, kaddr);
 887         else
 888                 __set_bit_le(bit, kaddr);
 889         kunmap_atomic(kaddr, KM_USER0);
 890         pr_debug("set file bit %lu page %lu\n", bit, page->index);
 891         /* record page number so it gets flushed to disk when unplug occurs */
 892         set_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 893 }
 894
 895 /* this gets called when the md device is ready to unplug its underlying
 896  * (slave) device queues -- before we let any writes go down, we need to
 897  * sync the dirty pages of the bitmap file to disk */
 898 void bitmap_unplug(struct bitmap *bitmap)
 899 {
 900         unsigned long i, flags;
 901         int dirty, need_write;
 902         struct page *page;
 903         int wait = 0;
 904
 905         if (!bitmap)
 906                 return;
 907
 908         /* look at each page to see if there are any set bits that need to be
 909          * flushed out to disk */
 910         for (i = 0; i < bitmap->file_pages; i++) {
 911                 spin_lock_irqsave(&bitmap->lock, flags);
 912                 if (!bitmap->filemap) {
 913                         spin_unlock_irqrestore(&bitmap->lock, flags);
 914                         return;
 915                 }
 916                 page = bitmap->filemap[i];
 917                 dirty = test_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 918                 need_write = test_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 919                 clear_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 920                 clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 921                 if (dirty)
 922                         wait = 1;
 923                 spin_unlock_irqrestore(&bitmap->lock, flags);
 924
 925                 if (dirty || need_write)
 926                         write_page(bitmap, page, 0);
 927         }
 928         if (wait) { /* if any writes were performed, we need to wait on them */
 929                 if (bitmap->file)
 930                         wait_event(bitmap->write_wait,
 931                                    atomic_read(&bitmap->pending_writes)==0);
 932                 else
 933                         md_super_wait(bitmap->mddev);
 934         }
 935         if (bitmap->flags & BITMAP_WRITE_ERROR)
 936                 bitmap_file_kick(bitmap);
 937 }
 938 EXPORT_SYMBOL(bitmap_unplug);
 939
 940 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
 941 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
 942  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
 943  * memory mapping of the bitmap file
 944  * Special cases:
 945  *   if there's no bitmap file, or if the bitmap file had been
 946  *   previously kicked from the array, we mark all the bits as
 947  *   1's in order to cause a full resync.
 948  *
 949  * We ignore all bits for sectors that end earlier than 'start'.
 950  * This is used when reading an out-of-date bitmap...
 951  */
 952 static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
 953 {
 954         unsigned long i, chunks, index, oldindex, bit;
 955         struct page *page = NULL, *oldpage = NULL;
 956         unsigned long num_pages, bit_cnt = 0;
 957         struct file *file;
 958         unsigned long bytes, offset;
 959         int outofdate;
 960         int ret = -ENOSPC;
 961         void *paddr;
 962
 963         chunks = bitmap->chunks;
 964         file = bitmap->file;
 965
 966         BUG_ON(!file && !bitmap->mddev->bitmap_info.offset);
 967
 968         outofdate = bitmap->flags & BITMAP_STALE;
 969         if (outofdate)
 970                 printk(KERN_INFO "%s: bitmap file is out of date, doing full "
 971                         "recovery\n", bmname(bitmap));
 972
 973         bytes = DIV_ROUND_UP(bitmap->chunks, 8);
 974         if (!bitmap->mddev->bitmap_info.external)
 975                 bytes += sizeof(bitmap_super_t);
 976
 977         num_pages = DIV_ROUND_UP(bytes, PAGE_SIZE);
 978
 979         if (file && i_size_read(file->f_mapping->host) < bytes) {
 980                 printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
 981                         bmname(bitmap),
 982                         (unsigned long) i_size_read(file->f_mapping->host),
 983                         bytes);
 984                 goto err;
 985         }
 986
 987         ret = -ENOMEM;
 988
 989         bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
 990         if (!bitmap->filemap)
 991                 goto err;
 992
 993         /* We need 4 bits per page, rounded up to a multiple of sizeof(unsigned long) */
 994         bitmap->filemap_attr = kzalloc(
 995                 roundup(DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
 996                 GFP_KERNEL);
 997         if (!bitmap->filemap_attr)
 998                 goto err;
 999
1000         oldindex = ~0L;
1001
1002         for (i = 0; i < chunks; i++) {
1003                 int b;
1004                 index = file_page_index(bitmap, i);
1005                 bit = file_page_offset(bitmap, i);
1006                 if (index != oldindex) { /* this is a new page, read it in */
1007                         int count;
1008                         /* unmap the old page, we're done with it */
1009                         if (index == num_pages-1)
1010                                 count = bytes - index * PAGE_SIZE;
1011                         else
1012                                 count = PAGE_SIZE;
1013                         if (index == 0 && bitmap->sb_page) {
1014                                 /*
1015                                  * if we're here then the superblock page
1016                                  * contains some bits (PAGE_SIZE != sizeof sb)
1017                                  * we've already read it in, so just use it
1018                                  */
1019                                 page = bitmap->sb_page;
1020                                 offset = sizeof(bitmap_super_t);
1021                                 if (!file)
1022                                         page = read_sb_page(
1023                                                 bitmap->mddev,
1024                                                 bitmap->mddev->bitmap_info.offset,
1025                                                 page,
1026                                                 index, count);
1027                         } else if (file) {
1028                                 page = read_page(file, index, bitmap, count);
1029                                 offset = 0;
1030                         } else {
1031                                 page = read_sb_page(bitmap->mddev,
1032                                                     bitmap->mddev->bitmap_info.offset,
1033                                                     NULL,
1034                                                     index, count);
1035                                 offset = 0;
1036                         }
1037                         if (IS_ERR(page)) { /* read error */
1038                                 ret = PTR_ERR(page);
1039                                 goto err;
1040                         }
1041
1042                         oldindex = index;
1043                         oldpage = page;
1044
1045                         bitmap->filemap[bitmap->file_pages++] = page;
1046                         bitmap->last_page_size = count;
1047
1048                         if (outofdate) {
1049                                 /*
1050                                  * if bitmap is out of date, dirty the
1051                                  * whole page and write it out
1052                                  */
1053                                 paddr = kmap_atomic(page, KM_USER0);
1054                                 memset(paddr + offset, 0xff,
1055                                        PAGE_SIZE - offset);
1056                                 kunmap_atomic(paddr, KM_USER0);
1057                                 write_page(bitmap, page, 1);
1058
1059                                 ret = -EIO;
1060                                 if (bitmap->flags & BITMAP_WRITE_ERROR)
1061                                         goto err;
1062                         }
1063                 }
1064                 paddr = kmap_atomic(page, KM_USER0);
1065                 if (bitmap->flags & BITMAP_HOSTENDIAN)
1066                         b = test_bit(bit, paddr);
1067                 else
1068                         b = test_bit_le(bit, paddr);
1069                 kunmap_atomic(paddr, KM_USER0);
1070                 if (b) {
1071                         /* if the disk bit is set, set the memory bit */
1072                         int needed = ((sector_t)(i+1) << (CHUNK_BLOCK_SHIFT(bitmap))
1073                                       >= start);
1074                         bitmap_set_memory_bits(bitmap,
1075                                                (sector_t)i << CHUNK_BLOCK_SHIFT(bitmap),
1076                                                needed);
1077                         bit_cnt++;
1078                 }
1079         }
1080
1081         /* everything went OK */
1082         ret = 0;
1083         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_UNSET);
1084
1085         if (bit_cnt) { /* Kick recovery if any bits were set */
1086                 set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
1087                 md_wakeup_thread(bitmap->mddev->thread);
1088         }
1089
1090         printk(KERN_INFO "%s: bitmap initialized from disk: "
1091                "read %lu/%lu pages, set %lu of %lu bits\n",
1092                bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt, chunks);
1093
1094         return 0;
1095
1096  err:
1097         printk(KERN_INFO "%s: bitmap initialisation failed: %d\n",
1098                bmname(bitmap), ret);
1099         return ret;
1100 }
1101
1102 void bitmap_write_all(struct bitmap *bitmap)
1103 {
1104         /* We don't actually write all bitmap blocks here,
1105          * just flag them as needing to be written
1106          */
1107         int i;
1108
1109         spin_lock_irq(&bitmap->lock);
1110         for (i = 0; i < bitmap->file_pages; i++)
1111                 set_page_attr(bitmap, bitmap->filemap[i],
1112                               BITMAP_PAGE_NEEDWRITE);
1113         bitmap->allclean = 0;
1114         spin_unlock_irq(&bitmap->lock);
1115 }
1116
1117 static void bitmap_count_page(struct bitmap *bitmap, sector_t offset, int inc)
1118 {
1119         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1120         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1121         bitmap->bp[page].count += inc;
1122         bitmap_checkfree(bitmap, page);
1123 }
1124 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1125                                             sector_t offset, sector_t *blocks,
1126                                             int create);
1127
1128 /*
1129  * bitmap daemon -- periodically wakes up to clean bits and flush pages
1130  *                      out to disk
1131  */
1132
1133 void bitmap_daemon_work(struct mddev *mddev)
1134 {
1135         struct bitmap *bitmap;
1136         unsigned long j;
1137         unsigned long flags;
1138         struct page *page = NULL, *lastpage = NULL;
1139         sector_t blocks;
1140         void *paddr;
1141
1142         /* Use a mutex to guard daemon_work against
1143          * bitmap_destroy.
1144          */
1145         mutex_lock(&mddev->bitmap_info.mutex);
1146         bitmap = mddev->bitmap;
1147         if (bitmap == NULL) {
1148                 mutex_unlock(&mddev->bitmap_info.mutex);
1149                 return;
1150         }
1151         if (time_before(jiffies, bitmap->daemon_lastrun
1152                         + bitmap->mddev->bitmap_info.daemon_sleep))
1153                 goto done;
1154
1155         bitmap->daemon_lastrun = jiffies;
1156         if (bitmap->allclean) {
1157                 bitmap->mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1158                 goto done;
1159         }
1160         bitmap->allclean = 1;
1161
1162         spin_lock_irqsave(&bitmap->lock, flags);
1163         for (j = 0; j < bitmap->chunks; j++) {
1164                 bitmap_counter_t *bmc;
1165                 if (!bitmap->filemap)
1166                         /* error or shutdown */
1167                         break;
1168
1169                 page = filemap_get_page(bitmap, j);
1170
1171                 if (page != lastpage) {
1172                         /* skip this page unless it's marked as needing cleaning */
1173                         if (!test_page_attr(bitmap, page, BITMAP_PAGE_PENDING)) {
1174                                 int need_write = test_page_attr(bitmap, page,
1175                                                                 BITMAP_PAGE_NEEDWRITE);
1176                                 if (need_write)
1177                                         clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
1178
1179                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1180                                 if (need_write)
1181                                         write_page(bitmap, page, 0);
1182                                 spin_lock_irqsave(&bitmap->lock, flags);
1183                                 j |= (PAGE_BITS - 1);
1184                                 continue;
1185                         }
1186
1187                         /* grab the new page, sync and release the old */
1188                         if (lastpage != NULL) {
1189                                 if (test_page_attr(bitmap, lastpage,
1190                                                    BITMAP_PAGE_NEEDWRITE)) {
1191                                         clear_page_attr(bitmap, lastpage,
1192                                                         BITMAP_PAGE_NEEDWRITE);
1193                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1194                                         write_page(bitmap, lastpage, 0);
1195                                 } else {
1196                                         set_page_attr(bitmap, lastpage,
1197                                                       BITMAP_PAGE_NEEDWRITE);
1198                                         bitmap->allclean = 0;
1199                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1200                                 }
1201                         } else
1202                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1203                         lastpage = page;
1204
1205                         /* We are possibly going to clear some bits, so make
1206                          * sure that events_cleared is up-to-date.
1207                          */
1208                         if (bitmap->need_sync &&
1209                             bitmap->mddev->bitmap_info.external == 0) {
1210                                 bitmap_super_t *sb;
1211                                 bitmap->need_sync = 0;
1212                                 sb = kmap_atomic(bitmap->sb_page, KM_USER0);
1213                                 sb->events_cleared =
1214                                         cpu_to_le64(bitmap->events_cleared);
1215                                 kunmap_atomic(sb, KM_USER0);
1216                                 write_page(bitmap, bitmap->sb_page, 1);
1217                         }
1218                         spin_lock_irqsave(&bitmap->lock, flags);
1219                         if (!bitmap->need_sync)
1220                                 clear_page_attr(bitmap, page, BITMAP_PAGE_PENDING);
1221                         else
1222                                 bitmap->allclean = 0;
1223                 }
1224                 bmc = bitmap_get_counter(bitmap,
1225                                          (sector_t)j << CHUNK_BLOCK_SHIFT(bitmap),
1226                                          &blocks, 0);
1227                 if (!bmc)
1228                         j |= PAGE_COUNTER_MASK;
1229                 else if (*bmc) {
1230                         if (*bmc == 1 && !bitmap->need_sync) {
1231                                 /* we can clear the bit */
1232                                 *bmc = 0;
1233                                 bitmap_count_page(bitmap,
1234                                                   (sector_t)j << CHUNK_BLOCK_SHIFT(bitmap),
1235                                                   -1);
1236
1237                                 /* clear the bit */
1238                                 paddr = kmap_atomic(page, KM_USER0);
1239                                 if (bitmap->flags & BITMAP_HOSTENDIAN)
1240                                         clear_bit(file_page_offset(bitmap, j),
1241                                                   paddr);
1242                                 else
1243                                         __clear_bit_le(
1244                                                 file_page_offset(bitmap,
1245                                                                  j),
1246                                                 paddr);
1247                                 kunmap_atomic(paddr, KM_USER0);
1248                         } else if (*bmc <= 2) {
1249                                 *bmc = 1; /* maybe clear the bit next time */
1250                                 set_page_attr(bitmap, page, BITMAP_PAGE_PENDING);
1251                                 bitmap->allclean = 0;
1252                         }
1253                 }
1254         }
1255         spin_unlock_irqrestore(&bitmap->lock, flags);
1256
1257         /* now sync the final page */
1258         if (lastpage != NULL) {
1259                 spin_lock_irqsave(&bitmap->lock, flags);
1260                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1261                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1262                         spin_unlock_irqrestore(&bitmap->lock, flags);
1263                         write_page(bitmap, lastpage, 0);
1264                 } else {
1265                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1266                         bitmap->allclean = 0;
1267                         spin_unlock_irqrestore(&bitmap->lock, flags);
1268                 }
1269         }
1270
1271  done:
1272         if (bitmap->allclean == 0)
1273                 bitmap->mddev->thread->timeout =
1274                         bitmap->mddev->bitmap_info.daemon_sleep;
1275         mutex_unlock(&mddev->bitmap_info.mutex);
1276 }
1277
1278 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1279                                             sector_t offset, sector_t *blocks,
1280                                             int create)
1281 __releases(bitmap->lock)
1282 __acquires(bitmap->lock)
1283 {
1284         /* If 'create', we might release the lock and reclaim it.
1285          * The lock must have been taken with interrupts enabled.
1286          * If !create, we don't release the lock.
1287          */
1288         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1289         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1290         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1291         sector_t csize;
1292         int err;
1293
1294         err = bitmap_checkpage(bitmap, page, create);
1295
1296         if (bitmap->bp[page].hijacked ||
1297             bitmap->bp[page].map == NULL)
1298                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap) +
1299                                           PAGE_COUNTER_SHIFT - 1);
1300         else
1301                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1302         *blocks = csize - (offset & (csize - 1));
1303
1304         if (err < 0)
1305                 return NULL;
1306
1307         /* now locked ... */
1308
1309         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1310                 /* should we use the first or second counter field
1311                  * of the hijacked pointer? */
1312                 int hi = (pageoff > PAGE_COUNTER_MASK);
1313                 return  &((bitmap_counter_t *)
1314                           &bitmap->bp[page].map)[hi];
1315         } else /* page is allocated */
1316                 return (bitmap_counter_t *)
1317                         &(bitmap->bp[page].map[pageoff]);
1318 }
1319
1320 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1321 {
1322         if (!bitmap)
1323                 return 0;
1324
1325         if (behind) {
1326                 int bw;
1327                 atomic_inc(&bitmap->behind_writes);
1328                 bw = atomic_read(&bitmap->behind_writes);
1329                 if (bw > bitmap->behind_writes_used)
1330                         bitmap->behind_writes_used = bw;
1331
1332                 pr_debug("inc write-behind count %d/%lu\n",
1333                          bw, bitmap->mddev->bitmap_info.max_write_behind);
1334         }
1335
1336         while (sectors) {
1337                 sector_t blocks;
1338                 bitmap_counter_t *bmc;
1339
1340                 spin_lock_irq(&bitmap->lock);
1341                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 1);
1342                 if (!bmc) {
1343                         spin_unlock_irq(&bitmap->lock);
1344                         return 0;
1345                 }
1346
1347                 if (unlikely(COUNTER(*bmc) == COUNTER_MAX)) {
1348                         DEFINE_WAIT(__wait);
1349                         /* note that it is safe to do the prepare_to_wait
1350                          * after the test as long as we do it before dropping
1351                          * the spinlock.
1352                          */
1353                         prepare_to_wait(&bitmap->overflow_wait, &__wait,
1354                                         TASK_UNINTERRUPTIBLE);
1355                         spin_unlock_irq(&bitmap->lock);
1356                         io_schedule();
1357                         finish_wait(&bitmap->overflow_wait, &__wait);
1358                         continue;
1359                 }
1360
1361                 switch (*bmc) {
1362                 case 0:
1363                         bitmap_file_set_bit(bitmap, offset);
1364                         bitmap_count_page(bitmap, offset, 1);
1365                         /* fall through */
1366                 case 1:
1367                         *bmc = 2;
1368                 }
1369
1370                 (*bmc)++;
1371
1372                 spin_unlock_irq(&bitmap->lock);
1373
1374                 offset += blocks;
1375                 if (sectors > blocks)
1376                         sectors -= blocks;
1377                 else
1378                         sectors = 0;
1379         }
1380         return 0;
1381 }
1382 EXPORT_SYMBOL(bitmap_startwrite);
1383
1384 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1385                      int success, int behind)
1386 {
1387         if (!bitmap)
1388                 return;
1389         if (behind) {
1390                 if (atomic_dec_and_test(&bitmap->behind_writes))
1391                         wake_up(&bitmap->behind_wait);
1392                 pr_debug("dec write-behind count %d/%lu\n",
1393                          atomic_read(&bitmap->behind_writes),
1394                          bitmap->mddev->bitmap_info.max_write_behind);
1395         }
1396         if (bitmap->mddev->degraded)
1397                 /* Never clear bits or update events_cleared when degraded */
1398                 success = 0;
1399
1400         while (sectors) {
1401                 sector_t blocks;
1402                 unsigned long flags;
1403                 bitmap_counter_t *bmc;
1404
1405                 spin_lock_irqsave(&bitmap->lock, flags);
1406                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 0);
1407                 if (!bmc) {
1408                         spin_unlock_irqrestore(&bitmap->lock, flags);
1409                         return;
1410                 }
1411
1412                 if (success &&
1413                     bitmap->events_cleared < bitmap->mddev->events) {
1414                         bitmap->events_cleared = bitmap->mddev->events;
1415                         bitmap->need_sync = 1;
1416                         sysfs_notify_dirent_safe(bitmap->sysfs_can_clear);
1417                 }
1418
1419                 if (!success && !NEEDED(*bmc))
1420                         *bmc |= NEEDED_MASK;
1421
1422                 if (COUNTER(*bmc) == COUNTER_MAX)
1423                         wake_up(&bitmap->overflow_wait);
1424
1425                 (*bmc)--;
1426                 if (*bmc <= 2) {
1427                         set_page_attr(bitmap,
1428                                       filemap_get_page(
1429                                               bitmap,
1430                                               offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1431                                       BITMAP_PAGE_PENDING);
1432                         bitmap->allclean = 0;
1433                 }
1434                 spin_unlock_irqrestore(&bitmap->lock, flags);
1435                 offset += blocks;
1436                 if (sectors > blocks)
1437                         sectors -= blocks;
1438                 else
1439                         sectors = 0;
1440         }
1441 }
1442 EXPORT_SYMBOL(bitmap_endwrite);
1443
1444 static int __bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1445                                int degraded)
1446 {
1447         bitmap_counter_t *bmc;
1448         int rv;
1449         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1450                 *blocks = 1024;
1451                 return 1; /* always resync if no bitmap */
1452         }
1453         spin_lock_irq(&bitmap->lock);
1454         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1455         rv = 0;
1456         if (bmc) {
1457                 /* locked */
1458                 if (RESYNC(*bmc))
1459                         rv = 1;
1460                 else if (NEEDED(*bmc)) {
1461                         rv = 1;
1462                         if (!degraded) { /* don't set/clear bits if degraded */
1463                                 *bmc |= RESYNC_MASK;
1464                                 *bmc &= ~NEEDED_MASK;
1465                         }
1466                 }
1467         }
1468         spin_unlock_irq(&bitmap->lock);
1469         return rv;
1470 }
1471
1472 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1473                       int degraded)
1474 {
1475         /* bitmap_start_sync must always report on multiples of whole
1476          * pages, otherwise resync (which is very PAGE_SIZE based) will
1477          * get confused.
1478          * So call __bitmap_start_sync repeatedly (if needed) until
1479          * At least PAGE_SIZE>>9 blocks are covered.
1480          * Return the 'or' of the result.
1481          */
1482         int rv = 0;
1483         sector_t blocks1;
1484
1485         *blocks = 0;
1486         while (*blocks < (PAGE_SIZE>>9)) {
1487                 rv |= __bitmap_start_sync(bitmap, offset,
1488                                           &blocks1, degraded);
1489                 offset += blocks1;
1490                 *blocks += blocks1;
1491         }
1492         return rv;
1493 }
1494 EXPORT_SYMBOL(bitmap_start_sync);
1495
1496 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks, int aborted)
1497 {
1498         bitmap_counter_t *bmc;
1499         unsigned long flags;
1500
1501         if (bitmap == NULL) {
1502                 *blocks = 1024;
1503                 return;
1504         }
1505         spin_lock_irqsave(&bitmap->lock, flags);
1506         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1507         if (bmc == NULL)
1508                 goto unlock;
1509         /* locked */
1510         if (RESYNC(*bmc)) {
1511                 *bmc &= ~RESYNC_MASK;
1512
1513                 if (!NEEDED(*bmc) && aborted)
1514                         *bmc |= NEEDED_MASK;
1515                 else {
1516                         if (*bmc <= 2) {
1517                                 set_page_attr(bitmap,
1518                                               filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1519                                               BITMAP_PAGE_PENDING);
1520                                 bitmap->allclean = 0;
1521                         }
1522                 }
1523         }
1524  unlock:
1525         spin_unlock_irqrestore(&bitmap->lock, flags);
1526 }
1527 EXPORT_SYMBOL(bitmap_end_sync);
1528
1529 void bitmap_close_sync(struct bitmap *bitmap)
1530 {
1531         /* Sync has finished, and any bitmap chunks that weren't synced
1532          * properly have been aborted.  It remains to us to clear the
1533          * RESYNC bit wherever it is still on
1534          */
1535         sector_t sector = 0;
1536         sector_t blocks;
1537         if (!bitmap)
1538                 return;
1539         while (sector < bitmap->mddev->resync_max_sectors) {
1540                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1541                 sector += blocks;
1542         }
1543 }
1544 EXPORT_SYMBOL(bitmap_close_sync);
1545
1546 void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector)
1547 {
1548         sector_t s = 0;
1549         sector_t blocks;
1550
1551         if (!bitmap)
1552                 return;
1553         if (sector == 0) {
1554                 bitmap->last_end_sync = jiffies;
1555                 return;
1556         }
1557         if (time_before(jiffies, (bitmap->last_end_sync
1558                                   + bitmap->mddev->bitmap_info.daemon_sleep)))
1559                 return;
1560         wait_event(bitmap->mddev->recovery_wait,
1561                    atomic_read(&bitmap->mddev->recovery_active) == 0);
1562
1563         bitmap->mddev->curr_resync_completed = sector;
1564         set_bit(MD_CHANGE_CLEAN, &bitmap->mddev->flags);
1565         sector &= ~((1ULL << CHUNK_BLOCK_SHIFT(bitmap)) - 1);
1566         s = 0;
1567         while (s < sector && s < bitmap->mddev->resync_max_sectors) {
1568                 bitmap_end_sync(bitmap, s, &blocks, 0);
1569                 s += blocks;
1570         }
1571         bitmap->last_end_sync = jiffies;
1572         sysfs_notify(&bitmap->mddev->kobj, NULL, "sync_completed");
1573 }
1574 EXPORT_SYMBOL(bitmap_cond_end_sync);
1575
1576 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1577 {
1578         /* For each chunk covered by any of these sectors, set the
1579          * counter to 1 and set resync_needed.  They should all
1580          * be 0 at this point
1581          */
1582
1583         sector_t secs;
1584         bitmap_counter_t *bmc;
1585         spin_lock_irq(&bitmap->lock);
1586         bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
1587         if (!bmc) {
1588                 spin_unlock_irq(&bitmap->lock);
1589                 return;
1590         }
1591         if (!*bmc) {
1592                 struct page *page;
1593                 *bmc = 1 | (needed ? NEEDED_MASK : 0);
1594                 bitmap_count_page(bitmap, offset, 1);
1595                 page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));
1596                 set_page_attr(bitmap, page, BITMAP_PAGE_PENDING);
1597                 bitmap->allclean = 0;
1598         }
1599         spin_unlock_irq(&bitmap->lock);
1600 }
1601
1602 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
1603 void bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1604 {
1605         unsigned long chunk;
1606
1607         for (chunk = s; chunk <= e; chunk++) {
1608                 sector_t sec = (sector_t)chunk << CHUNK_BLOCK_SHIFT(bitmap);
1609                 bitmap_set_memory_bits(bitmap, sec, 1);
1610                 spin_lock_irq(&bitmap->lock);
1611                 bitmap_file_set_bit(bitmap, sec);
1612                 spin_unlock_irq(&bitmap->lock);
1613                 if (sec < bitmap->mddev->recovery_cp)
1614                         /* We are asserting that the array is dirty,
1615                          * so move the recovery_cp address back so
1616                          * that it is obvious that it is dirty
1617                          */
1618                         bitmap->mddev->recovery_cp = sec;
1619         }
1620 }
1621
1622 /*
1623  * flush out any pending updates
1624  */
1625 void bitmap_flush(struct mddev *mddev)
1626 {
1627         struct bitmap *bitmap = mddev->bitmap;
1628         long sleep;
1629
1630         if (!bitmap) /* there was no bitmap */
1631                 return;
1632
1633         /* run the daemon_work three time to ensure everything is flushed
1634          * that can be
1635          */
1636         sleep = mddev->bitmap_info.daemon_sleep * 2;
1637         bitmap->daemon_lastrun -= sleep;
1638         bitmap_daemon_work(mddev);
1639         bitmap->daemon_lastrun -= sleep;
1640         bitmap_daemon_work(mddev);
1641         bitmap->daemon_lastrun -= sleep;
1642         bitmap_daemon_work(mddev);
1643         bitmap_update_sb(bitmap);
1644 }
1645
1646 /*
1647  * free memory that was allocated
1648  */
1649 static void bitmap_free(struct bitmap *bitmap)
1650 {
1651         unsigned long k, pages;
1652         struct bitmap_page *bp;
1653
1654         if (!bitmap) /* there was no bitmap */
1655                 return;
1656
1657         /* release the bitmap file and kill the daemon */
1658         bitmap_file_put(bitmap);
1659
1660         bp = bitmap->bp;
1661         pages = bitmap->pages;
1662
1663         /* free all allocated memory */
1664
1665         if (bp) /* deallocate the page memory */
1666                 for (k = 0; k < pages; k++)
1667                         if (bp[k].map && !bp[k].hijacked)
1668                                 kfree(bp[k].map);
1669         kfree(bp);
1670         kfree(bitmap);
1671 }
1672
1673 void bitmap_destroy(struct mddev *mddev)
1674 {
1675         struct bitmap *bitmap = mddev->bitmap;
1676
1677         if (!bitmap) /* there was no bitmap */
1678                 return;
1679
1680         mutex_lock(&mddev->bitmap_info.mutex);
1681         mddev->bitmap = NULL; /* disconnect from the md device */
1682         mutex_unlock(&mddev->bitmap_info.mutex);
1683         if (mddev->thread)
1684                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1685
1686         if (bitmap->sysfs_can_clear)
1687                 sysfs_put(bitmap->sysfs_can_clear);
1688
1689         bitmap_free(bitmap);
1690 }
1691
1692 /*
1693  * initialize the bitmap structure
1694  * if this returns an error, bitmap_destroy must be called to do clean up
1695  */
1696 int bitmap_create(struct mddev *mddev)
1697 {
1698         struct bitmap *bitmap;
1699         sector_t blocks = mddev->resync_max_sectors;
1700         unsigned long chunks;
1701         unsigned long pages;
1702         struct file *file = mddev->bitmap_info.file;
1703         int err;
1704         struct sysfs_dirent *bm = NULL;
1705
1706         BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
1707
1708         if (!file
1709             && !mddev->bitmap_info.offset) /* bitmap disabled, nothing to do */
1710                 return 0;
1711
1712         BUG_ON(file && mddev->bitmap_info.offset);
1713
1714         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1715         if (!bitmap)
1716                 return -ENOMEM;
1717
1718         spin_lock_init(&bitmap->lock);
1719         atomic_set(&bitmap->pending_writes, 0);
1720         init_waitqueue_head(&bitmap->write_wait);
1721         init_waitqueue_head(&bitmap->overflow_wait);
1722         init_waitqueue_head(&bitmap->behind_wait);
1723
1724         bitmap->mddev = mddev;
1725
1726         if (mddev->kobj.sd)
1727                 bm = sysfs_get_dirent(mddev->kobj.sd, NULL, "bitmap");
1728         if (bm) {
1729                 bitmap->sysfs_can_clear = sysfs_get_dirent(bm, NULL, "can_clear");
1730                 sysfs_put(bm);
1731         } else
1732                 bitmap->sysfs_can_clear = NULL;
1733
1734         bitmap->file = file;
1735         if (file) {
1736                 get_file(file);
1737                 /* As future accesses to this file will use bmap,
1738                  * and bypass the page cache, we must sync the file
1739                  * first.
1740                  */
1741                 vfs_fsync(file, 1);
1742         }
1743         /* read superblock from bitmap file (this sets mddev->bitmap_info.chunksize) */
1744         if (!mddev->bitmap_info.external) {
1745                 /*
1746                  * If 'MD_ARRAY_FIRST_USE' is set, then device-mapper is
1747                  * instructing us to create a new on-disk bitmap instance.
1748                  */
1749                 if (test_and_clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags))
1750                         err = bitmap_new_disk_sb(bitmap);
1751                 else
1752                         err = bitmap_read_sb(bitmap);
1753         } else {
1754                 err = 0;
1755                 if (mddev->bitmap_info.chunksize == 0 ||
1756                     mddev->bitmap_info.daemon_sleep == 0)
1757                         /* chunksize and time_base need to be
1758                          * set first. */
1759                         err = -EINVAL;
1760         }
1761         if (err)
1762                 goto error;
1763
1764         bitmap->daemon_lastrun = jiffies;
1765         bitmap->chunkshift = ffz(~mddev->bitmap_info.chunksize);
1766
1767         /* now that chunksize and chunkshift are set, we can use these macros */
1768         chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) >>
1769                         CHUNK_BLOCK_SHIFT(bitmap);
1770         pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
1771
1772         BUG_ON(!pages);
1773
1774         bitmap->chunks = chunks;
1775         bitmap->pages = pages;
1776         bitmap->missing_pages = pages;
1777
1778         bitmap->bp = kzalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
1779
1780         err = -ENOMEM;
1781         if (!bitmap->bp)
1782                 goto error;
1783
1784         printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
1785                 pages, bmname(bitmap));
1786
1787         mddev->bitmap = bitmap;
1788
1789
1790         return (bitmap->flags & BITMAP_WRITE_ERROR) ? -EIO : 0;
1791
1792  error:
1793         bitmap_free(bitmap);
1794         return err;
1795 }
1796
1797 int bitmap_load(struct mddev *mddev)
1798 {
1799         int err = 0;
1800         sector_t start = 0;
1801         sector_t sector = 0;
1802         struct bitmap *bitmap = mddev->bitmap;
1803
1804         if (!bitmap)
1805                 goto out;
1806
1807         /* Clear out old bitmap info first:  Either there is none, or we
1808          * are resuming after someone else has possibly changed things,
1809          * so we should forget old cached info.
1810          * All chunks should be clean, but some might need_sync.
1811          */
1812         while (sector < mddev->resync_max_sectors) {
1813                 sector_t blocks;
1814                 bitmap_start_sync(bitmap, sector, &blocks, 0);
1815                 sector += blocks;
1816         }
1817         bitmap_close_sync(bitmap);
1818
1819         if (mddev->degraded == 0
1820             || bitmap->events_cleared == mddev->events)
1821                 /* no need to keep dirty bits to optimise a
1822                  * re-add of a missing device */
1823                 start = mddev->recovery_cp;
1824
1825         err = bitmap_init_from_disk(bitmap, start);
1826
1827         if (err)
1828                 goto out;
1829
1830         mddev->thread->timeout = mddev->bitmap_info.daemon_sleep;
1831         md_wakeup_thread(mddev->thread);
1832
1833         bitmap_update_sb(bitmap);
1834
1835         if (bitmap->flags & BITMAP_WRITE_ERROR)
1836                 err = -EIO;
1837 out:
1838         return err;
1839 }
1840 EXPORT_SYMBOL_GPL(bitmap_load);
1841
1842 static ssize_t
1843 location_show(struct mddev *mddev, char *page)
1844 {
1845         ssize_t len;
1846         if (mddev->bitmap_info.file)
1847                 len = sprintf(page, "file");
1848         else if (mddev->bitmap_info.offset)
1849                 len = sprintf(page, "%+lld", (long long)mddev->bitmap_info.offset);
1850         else
1851                 len = sprintf(page, "none");
1852         len += sprintf(page+len, "\n");
1853         return len;
1854 }
1855
1856 static ssize_t
1857 location_store(struct mddev *mddev, const char *buf, size_t len)
1858 {
1859
1860         if (mddev->pers) {
1861                 if (!mddev->pers->quiesce)
1862                         return -EBUSY;
1863                 if (mddev->recovery || mddev->sync_thread)
1864                         return -EBUSY;
1865         }
1866
1867         if (mddev->bitmap || mddev->bitmap_info.file ||
1868             mddev->bitmap_info.offset) {
1869                 /* bitmap already configured.  Only option is to clear it */
1870                 if (strncmp(buf, "none", 4) != 0)
1871                         return -EBUSY;
1872                 if (mddev->pers) {
1873                         mddev->pers->quiesce(mddev, 1);
1874                         bitmap_destroy(mddev);
1875                         mddev->pers->quiesce(mddev, 0);
1876                 }
1877                 mddev->bitmap_info.offset = 0;
1878                 if (mddev->bitmap_info.file) {
1879                         struct file *f = mddev->bitmap_info.file;
1880                         mddev->bitmap_info.file = NULL;
1881                         restore_bitmap_write_access(f);
1882                         fput(f);
1883                 }
1884         } else {
1885                 /* No bitmap, OK to set a location */
1886                 long long offset;
1887                 if (strncmp(buf, "none", 4) == 0)
1888                         /* nothing to be done */;
1889                 else if (strncmp(buf, "file:", 5) == 0) {
1890                         /* Not supported yet */
1891                         return -EINVAL;
1892                 } else {
1893                         int rv;
1894                         if (buf[0] == '+')
1895                                 rv = strict_strtoll(buf+1, 10, &offset);
1896                         else
1897                                 rv = strict_strtoll(buf, 10, &offset);
1898                         if (rv)
1899                                 return rv;
1900                         if (offset == 0)
1901                                 return -EINVAL;
1902                         if (mddev->bitmap_info.external == 0 &&
1903                             mddev->major_version == 0 &&
1904                             offset != mddev->bitmap_info.default_offset)
1905                                 return -EINVAL;
1906                         mddev->bitmap_info.offset = offset;
1907                         if (mddev->pers) {
1908                                 mddev->pers->quiesce(mddev, 1);
1909                                 rv = bitmap_create(mddev);
1910                                 if (rv) {
1911                                         bitmap_destroy(mddev);
1912                                         mddev->bitmap_info.offset = 0;
1913                                 }
1914                                 mddev->pers->quiesce(mddev, 0);
1915                                 if (rv)
1916                                         return rv;
1917                         }
1918                 }
1919         }
1920         if (!mddev->external) {
1921                 /* Ensure new bitmap info is stored in
1922                  * metadata promptly.
1923                  */
1924                 set_bit(MD_CHANGE_DEVS, &mddev->flags);
1925                 md_wakeup_thread(mddev->thread);
1926         }
1927         return len;
1928 }
1929
1930 static struct md_sysfs_entry bitmap_location =
1931 __ATTR(location, S_IRUGO|S_IWUSR, location_show, location_store);
1932
1933 static ssize_t
1934 timeout_show(struct mddev *mddev, char *page)
1935 {
1936         ssize_t len;
1937         unsigned long secs = mddev->bitmap_info.daemon_sleep / HZ;
1938         unsigned long jifs = mddev->bitmap_info.daemon_sleep % HZ;
1939
1940         len = sprintf(page, "%lu", secs);
1941         if (jifs)
1942                 len += sprintf(page+len, ".%03u", jiffies_to_msecs(jifs));
1943         len += sprintf(page+len, "\n");
1944         return len;
1945 }
1946
1947 static ssize_t
1948 timeout_store(struct mddev *mddev, const char *buf, size_t len)
1949 {
1950         /* timeout can be set at any time */
1951         unsigned long timeout;
1952         int rv = strict_strtoul_scaled(buf, &timeout, 4);
1953         if (rv)
1954                 return rv;
1955
1956         /* just to make sure we don't overflow... */
1957         if (timeout >= LONG_MAX / HZ)
1958                 return -EINVAL;
1959
1960         timeout = timeout * HZ / 10000;
1961
1962         if (timeout >= MAX_SCHEDULE_TIMEOUT)
1963                 timeout = MAX_SCHEDULE_TIMEOUT-1;
1964         if (timeout < 1)
1965                 timeout = 1;
1966         mddev->bitmap_info.daemon_sleep = timeout;
1967         if (mddev->thread) {
1968                 /* if thread->timeout is MAX_SCHEDULE_TIMEOUT, then
1969                  * the bitmap is all clean and we don't need to
1970                  * adjust the timeout right now
1971                  */
1972                 if (mddev->thread->timeout < MAX_SCHEDULE_TIMEOUT) {
1973                         mddev->thread->timeout = timeout;
1974                         md_wakeup_thread(mddev->thread);
1975                 }
1976         }
1977         return len;
1978 }
1979
1980 static struct md_sysfs_entry bitmap_timeout =
1981 __ATTR(time_base, S_IRUGO|S_IWUSR, timeout_show, timeout_store);
1982
1983 static ssize_t
1984 backlog_show(struct mddev *mddev, char *page)
1985 {
1986         return sprintf(page, "%lu\n", mddev->bitmap_info.max_write_behind);
1987 }
1988
1989 static ssize_t
1990 backlog_store(struct mddev *mddev, const char *buf, size_t len)
1991 {
1992         unsigned long backlog;
1993         int rv = strict_strtoul(buf, 10, &backlog);
1994         if (rv)
1995                 return rv;
1996         if (backlog > COUNTER_MAX)
1997                 return -EINVAL;
1998         mddev->bitmap_info.max_write_behind = backlog;
1999         return len;
2000 }
2001
2002 static struct md_sysfs_entry bitmap_backlog =
2003 __ATTR(backlog, S_IRUGO|S_IWUSR, backlog_show, backlog_store);
2004
2005 static ssize_t
2006 chunksize_show(struct mddev *mddev, char *page)
2007 {
2008         return sprintf(page, "%lu\n", mddev->bitmap_info.chunksize);
2009 }
2010
2011 static ssize_t
2012 chunksize_store(struct mddev *mddev, const char *buf, size_t len)
2013 {
2014         /* Can only be changed when no bitmap is active */
2015         int rv;
2016         unsigned long csize;
2017         if (mddev->bitmap)
2018                 return -EBUSY;
2019         rv = strict_strtoul(buf, 10, &csize);
2020         if (rv)
2021                 return rv;
2022         if (csize < 512 ||
2023             !is_power_of_2(csize))
2024                 return -EINVAL;
2025         mddev->bitmap_info.chunksize = csize;
2026         return len;
2027 }
2028
2029 static struct md_sysfs_entry bitmap_chunksize =
2030 __ATTR(chunksize, S_IRUGO|S_IWUSR, chunksize_show, chunksize_store);
2031
2032 static ssize_t metadata_show(struct mddev *mddev, char *page)
2033 {
2034         return sprintf(page, "%s\n", (mddev->bitmap_info.external
2035                                       ? "external" : "internal"));
2036 }
2037
2038 static ssize_t metadata_store(struct mddev *mddev, const char *buf, size_t len)
2039 {
2040         if (mddev->bitmap ||
2041             mddev->bitmap_info.file ||
2042             mddev->bitmap_info.offset)
2043                 return -EBUSY;
2044         if (strncmp(buf, "external", 8) == 0)
2045                 mddev->bitmap_info.external = 1;
2046         else if (strncmp(buf, "internal", 8) == 0)
2047                 mddev->bitmap_info.external = 0;
2048         else
2049                 return -EINVAL;
2050         return len;
2051 }
2052
2053 static struct md_sysfs_entry bitmap_metadata =
2054 __ATTR(metadata, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
2055
2056 static ssize_t can_clear_show(struct mddev *mddev, char *page)
2057 {
2058         int len;
2059         if (mddev->bitmap)
2060                 len = sprintf(page, "%s\n", (mddev->bitmap->need_sync ?
2061                                              "false" : "true"));
2062         else
2063                 len = sprintf(page, "\n");
2064         return len;
2065 }
2066
2067 static ssize_t can_clear_store(struct mddev *mddev, const char *buf, size_t len)
2068 {
2069         if (mddev->bitmap == NULL)
2070                 return -ENOENT;
2071         if (strncmp(buf, "false", 5) == 0)
2072                 mddev->bitmap->need_sync = 1;
2073         else if (strncmp(buf, "true", 4) == 0) {
2074                 if (mddev->degraded)
2075                         return -EBUSY;
2076                 mddev->bitmap->need_sync = 0;
2077         } else
2078                 return -EINVAL;
2079         return len;
2080 }
2081
2082 static struct md_sysfs_entry bitmap_can_clear =
2083 __ATTR(can_clear, S_IRUGO|S_IWUSR, can_clear_show, can_clear_store);
2084
2085 static ssize_t
2086 behind_writes_used_show(struct mddev *mddev, char *page)
2087 {
2088         if (mddev->bitmap == NULL)
2089                 return sprintf(page, "0\n");
2090         return sprintf(page, "%lu\n",
2091                        mddev->bitmap->behind_writes_used);
2092 }
2093
2094 static ssize_t
2095 behind_writes_used_reset(struct mddev *mddev, const char *buf, size_t len)
2096 {
2097         if (mddev->bitmap)
2098                 mddev->bitmap->behind_writes_used = 0;
2099         return len;
2100 }
2101
2102 static struct md_sysfs_entry max_backlog_used =
2103 __ATTR(max_backlog_used, S_IRUGO | S_IWUSR,
2104        behind_writes_used_show, behind_writes_used_reset);
2105
2106 static struct attribute *md_bitmap_attrs[] = {
2107         &bitmap_location.attr,
2108         &bitmap_timeout.attr,
2109         &bitmap_backlog.attr,
2110         &bitmap_chunksize.attr,
2111         &bitmap_metadata.attr,
2112         &bitmap_can_clear.attr,
2113         &max_backlog_used.attr,
2114         NULL
2115 };
2116 struct attribute_group md_bitmap_group = {
2117         .name = "bitmap",
2118         .attrs = md_bitmap_attrs,
2119 };
2120