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
1397         while (sectors) {
1398                 sector_t blocks;
1399                 unsigned long flags;
1400                 bitmap_counter_t *bmc;
1401
1402                 spin_lock_irqsave(&bitmap->lock, flags);
1403                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 0);
1404                 if (!bmc) {
1405                         spin_unlock_irqrestore(&bitmap->lock, flags);
1406                         return;
1407                 }
1408
1409                 if (success && !bitmap->mddev->degraded &&
1410                     bitmap->events_cleared < bitmap->mddev->events) {
1411                         bitmap->events_cleared = bitmap->mddev->events;
1412                         bitmap->need_sync = 1;
1413                         sysfs_notify_dirent_safe(bitmap->sysfs_can_clear);
1414                 }
1415
1416                 if (!success && !NEEDED(*bmc))
1417                         *bmc |= NEEDED_MASK;
1418
1419                 if (COUNTER(*bmc) == COUNTER_MAX)
1420                         wake_up(&bitmap->overflow_wait);
1421
1422                 (*bmc)--;
1423                 if (*bmc <= 2) {
1424                         set_page_attr(bitmap,
1425                                       filemap_get_page(
1426                                               bitmap,
1427                                               offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1428                                       BITMAP_PAGE_PENDING);
1429                         bitmap->allclean = 0;
1430                 }
1431                 spin_unlock_irqrestore(&bitmap->lock, flags);
1432                 offset += blocks;
1433                 if (sectors > blocks)
1434                         sectors -= blocks;
1435                 else
1436                         sectors = 0;
1437         }
1438 }
1439 EXPORT_SYMBOL(bitmap_endwrite);
1440
1441 static int __bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1442                                int degraded)
1443 {
1444         bitmap_counter_t *bmc;
1445         int rv;
1446         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1447                 *blocks = 1024;
1448                 return 1; /* always resync if no bitmap */
1449         }
1450         spin_lock_irq(&bitmap->lock);
1451         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1452         rv = 0;
1453         if (bmc) {
1454                 /* locked */
1455                 if (RESYNC(*bmc))
1456                         rv = 1;
1457                 else if (NEEDED(*bmc)) {
1458                         rv = 1;
1459                         if (!degraded) { /* don't set/clear bits if degraded */
1460                                 *bmc |= RESYNC_MASK;
1461                                 *bmc &= ~NEEDED_MASK;
1462                         }
1463                 }
1464         }
1465         spin_unlock_irq(&bitmap->lock);
1466         return rv;
1467 }
1468
1469 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1470                       int degraded)
1471 {
1472         /* bitmap_start_sync must always report on multiples of whole
1473          * pages, otherwise resync (which is very PAGE_SIZE based) will
1474          * get confused.
1475          * So call __bitmap_start_sync repeatedly (if needed) until
1476          * At least PAGE_SIZE>>9 blocks are covered.
1477          * Return the 'or' of the result.
1478          */
1479         int rv = 0;
1480         sector_t blocks1;
1481
1482         *blocks = 0;
1483         while (*blocks < (PAGE_SIZE>>9)) {
1484                 rv |= __bitmap_start_sync(bitmap, offset,
1485                                           &blocks1, degraded);
1486                 offset += blocks1;
1487                 *blocks += blocks1;
1488         }
1489         return rv;
1490 }
1491 EXPORT_SYMBOL(bitmap_start_sync);
1492
1493 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks, int aborted)
1494 {
1495         bitmap_counter_t *bmc;
1496         unsigned long flags;
1497
1498         if (bitmap == NULL) {
1499                 *blocks = 1024;
1500                 return;
1501         }
1502         spin_lock_irqsave(&bitmap->lock, flags);
1503         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1504         if (bmc == NULL)
1505                 goto unlock;
1506         /* locked */
1507         if (RESYNC(*bmc)) {
1508                 *bmc &= ~RESYNC_MASK;
1509
1510                 if (!NEEDED(*bmc) && aborted)
1511                         *bmc |= NEEDED_MASK;
1512                 else {
1513                         if (*bmc <= 2) {
1514                                 set_page_attr(bitmap,
1515                                               filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1516                                               BITMAP_PAGE_PENDING);
1517                                 bitmap->allclean = 0;
1518                         }
1519                 }
1520         }
1521  unlock:
1522         spin_unlock_irqrestore(&bitmap->lock, flags);
1523 }
1524 EXPORT_SYMBOL(bitmap_end_sync);
1525
1526 void bitmap_close_sync(struct bitmap *bitmap)
1527 {
1528         /* Sync has finished, and any bitmap chunks that weren't synced
1529          * properly have been aborted.  It remains to us to clear the
1530          * RESYNC bit wherever it is still on
1531          */
1532         sector_t sector = 0;
1533         sector_t blocks;
1534         if (!bitmap)
1535                 return;
1536         while (sector < bitmap->mddev->resync_max_sectors) {
1537                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1538                 sector += blocks;
1539         }
1540 }
1541 EXPORT_SYMBOL(bitmap_close_sync);
1542
1543 void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector)
1544 {
1545         sector_t s = 0;
1546         sector_t blocks;
1547
1548         if (!bitmap)
1549                 return;
1550         if (sector == 0) {
1551                 bitmap->last_end_sync = jiffies;
1552                 return;
1553         }
1554         if (time_before(jiffies, (bitmap->last_end_sync
1555                                   + bitmap->mddev->bitmap_info.daemon_sleep)))
1556                 return;
1557         wait_event(bitmap->mddev->recovery_wait,
1558                    atomic_read(&bitmap->mddev->recovery_active) == 0);
1559
1560         bitmap->mddev->curr_resync_completed = sector;
1561         set_bit(MD_CHANGE_CLEAN, &bitmap->mddev->flags);
1562         sector &= ~((1ULL << CHUNK_BLOCK_SHIFT(bitmap)) - 1);
1563         s = 0;
1564         while (s < sector && s < bitmap->mddev->resync_max_sectors) {
1565                 bitmap_end_sync(bitmap, s, &blocks, 0);
1566                 s += blocks;
1567         }
1568         bitmap->last_end_sync = jiffies;
1569         sysfs_notify(&bitmap->mddev->kobj, NULL, "sync_completed");
1570 }
1571 EXPORT_SYMBOL(bitmap_cond_end_sync);
1572
1573 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1574 {
1575         /* For each chunk covered by any of these sectors, set the
1576          * counter to 1 and set resync_needed.  They should all
1577          * be 0 at this point
1578          */
1579
1580         sector_t secs;
1581         bitmap_counter_t *bmc;
1582         spin_lock_irq(&bitmap->lock);
1583         bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
1584         if (!bmc) {
1585                 spin_unlock_irq(&bitmap->lock);
1586                 return;
1587         }
1588         if (!*bmc) {
1589                 struct page *page;
1590                 *bmc = 1 | (needed ? NEEDED_MASK : 0);
1591                 bitmap_count_page(bitmap, offset, 1);
1592                 page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));
1593                 set_page_attr(bitmap, page, BITMAP_PAGE_PENDING);
1594                 bitmap->allclean = 0;
1595         }
1596         spin_unlock_irq(&bitmap->lock);
1597 }
1598
1599 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
1600 void bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1601 {
1602         unsigned long chunk;
1603
1604         for (chunk = s; chunk <= e; chunk++) {
1605                 sector_t sec = (sector_t)chunk << CHUNK_BLOCK_SHIFT(bitmap);
1606                 bitmap_set_memory_bits(bitmap, sec, 1);
1607                 spin_lock_irq(&bitmap->lock);
1608                 bitmap_file_set_bit(bitmap, sec);
1609                 spin_unlock_irq(&bitmap->lock);
1610                 if (sec < bitmap->mddev->recovery_cp)
1611                         /* We are asserting that the array is dirty,
1612                          * so move the recovery_cp address back so
1613                          * that it is obvious that it is dirty
1614                          */
1615                         bitmap->mddev->recovery_cp = sec;
1616         }
1617 }
1618
1619 /*
1620  * flush out any pending updates
1621  */
1622 void bitmap_flush(struct mddev *mddev)
1623 {
1624         struct bitmap *bitmap = mddev->bitmap;
1625         long sleep;
1626
1627         if (!bitmap) /* there was no bitmap */
1628                 return;
1629
1630         /* run the daemon_work three time to ensure everything is flushed
1631          * that can be
1632          */
1633         sleep = mddev->bitmap_info.daemon_sleep * 2;
1634         bitmap->daemon_lastrun -= sleep;
1635         bitmap_daemon_work(mddev);
1636         bitmap->daemon_lastrun -= sleep;
1637         bitmap_daemon_work(mddev);
1638         bitmap->daemon_lastrun -= sleep;
1639         bitmap_daemon_work(mddev);
1640         bitmap_update_sb(bitmap);
1641 }
1642
1643 /*
1644  * free memory that was allocated
1645  */
1646 static void bitmap_free(struct bitmap *bitmap)
1647 {
1648         unsigned long k, pages;
1649         struct bitmap_page *bp;
1650
1651         if (!bitmap) /* there was no bitmap */
1652                 return;
1653
1654         /* release the bitmap file and kill the daemon */
1655         bitmap_file_put(bitmap);
1656
1657         bp = bitmap->bp;
1658         pages = bitmap->pages;
1659
1660         /* free all allocated memory */
1661
1662         if (bp) /* deallocate the page memory */
1663                 for (k = 0; k < pages; k++)
1664                         if (bp[k].map && !bp[k].hijacked)
1665                                 kfree(bp[k].map);
1666         kfree(bp);
1667         kfree(bitmap);
1668 }
1669
1670 void bitmap_destroy(struct mddev *mddev)
1671 {
1672         struct bitmap *bitmap = mddev->bitmap;
1673
1674         if (!bitmap) /* there was no bitmap */
1675                 return;
1676
1677         mutex_lock(&mddev->bitmap_info.mutex);
1678         mddev->bitmap = NULL; /* disconnect from the md device */
1679         mutex_unlock(&mddev->bitmap_info.mutex);
1680         if (mddev->thread)
1681                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1682
1683         if (bitmap->sysfs_can_clear)
1684                 sysfs_put(bitmap->sysfs_can_clear);
1685
1686         bitmap_free(bitmap);
1687 }
1688
1689 /*
1690  * initialize the bitmap structure
1691  * if this returns an error, bitmap_destroy must be called to do clean up
1692  */
1693 int bitmap_create(struct mddev *mddev)
1694 {
1695         struct bitmap *bitmap;
1696         sector_t blocks = mddev->resync_max_sectors;
1697         unsigned long chunks;
1698         unsigned long pages;
1699         struct file *file = mddev->bitmap_info.file;
1700         int err;
1701         struct sysfs_dirent *bm = NULL;
1702
1703         BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
1704
1705         if (!file
1706             && !mddev->bitmap_info.offset) /* bitmap disabled, nothing to do */
1707                 return 0;
1708
1709         BUG_ON(file && mddev->bitmap_info.offset);
1710
1711         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1712         if (!bitmap)
1713                 return -ENOMEM;
1714
1715         spin_lock_init(&bitmap->lock);
1716         atomic_set(&bitmap->pending_writes, 0);
1717         init_waitqueue_head(&bitmap->write_wait);
1718         init_waitqueue_head(&bitmap->overflow_wait);
1719         init_waitqueue_head(&bitmap->behind_wait);
1720
1721         bitmap->mddev = mddev;
1722
1723         if (mddev->kobj.sd)
1724                 bm = sysfs_get_dirent(mddev->kobj.sd, NULL, "bitmap");
1725         if (bm) {
1726                 bitmap->sysfs_can_clear = sysfs_get_dirent(bm, NULL, "can_clear");
1727                 sysfs_put(bm);
1728         } else
1729                 bitmap->sysfs_can_clear = NULL;
1730
1731         bitmap->file = file;
1732         if (file) {
1733                 get_file(file);
1734                 /* As future accesses to this file will use bmap,
1735                  * and bypass the page cache, we must sync the file
1736                  * first.
1737                  */
1738                 vfs_fsync(file, 1);
1739         }
1740         /* read superblock from bitmap file (this sets mddev->bitmap_info.chunksize) */
1741         if (!mddev->bitmap_info.external) {
1742                 /*
1743                  * If 'MD_ARRAY_FIRST_USE' is set, then device-mapper is
1744                  * instructing us to create a new on-disk bitmap instance.
1745                  */
1746                 if (test_and_clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags))
1747                         err = bitmap_new_disk_sb(bitmap);
1748                 else
1749                         err = bitmap_read_sb(bitmap);
1750         } else {
1751                 err = 0;
1752                 if (mddev->bitmap_info.chunksize == 0 ||
1753                     mddev->bitmap_info.daemon_sleep == 0)
1754                         /* chunksize and time_base need to be
1755                          * set first. */
1756                         err = -EINVAL;
1757         }
1758         if (err)
1759                 goto error;
1760
1761         bitmap->daemon_lastrun = jiffies;
1762         bitmap->chunkshift = ffz(~mddev->bitmap_info.chunksize);
1763
1764         /* now that chunksize and chunkshift are set, we can use these macros */
1765         chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) >>
1766                         CHUNK_BLOCK_SHIFT(bitmap);
1767         pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
1768
1769         BUG_ON(!pages);
1770
1771         bitmap->chunks = chunks;
1772         bitmap->pages = pages;
1773         bitmap->missing_pages = pages;
1774
1775         bitmap->bp = kzalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
1776
1777         err = -ENOMEM;
1778         if (!bitmap->bp)
1779                 goto error;
1780
1781         printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
1782                 pages, bmname(bitmap));
1783
1784         mddev->bitmap = bitmap;
1785
1786
1787         return (bitmap->flags & BITMAP_WRITE_ERROR) ? -EIO : 0;
1788
1789  error:
1790         bitmap_free(bitmap);
1791         return err;
1792 }
1793
1794 int bitmap_load(struct mddev *mddev)
1795 {
1796         int err = 0;
1797         sector_t start = 0;
1798         sector_t sector = 0;
1799         struct bitmap *bitmap = mddev->bitmap;
1800
1801         if (!bitmap)
1802                 goto out;
1803
1804         /* Clear out old bitmap info first:  Either there is none, or we
1805          * are resuming after someone else has possibly changed things,
1806          * so we should forget old cached info.
1807          * All chunks should be clean, but some might need_sync.
1808          */
1809         while (sector < mddev->resync_max_sectors) {
1810                 sector_t blocks;
1811                 bitmap_start_sync(bitmap, sector, &blocks, 0);
1812                 sector += blocks;
1813         }
1814         bitmap_close_sync(bitmap);
1815
1816         if (mddev->degraded == 0
1817             || bitmap->events_cleared == mddev->events)
1818                 /* no need to keep dirty bits to optimise a
1819                  * re-add of a missing device */
1820                 start = mddev->recovery_cp;
1821
1822         err = bitmap_init_from_disk(bitmap, start);
1823
1824         if (err)
1825                 goto out;
1826
1827         mddev->thread->timeout = mddev->bitmap_info.daemon_sleep;
1828         md_wakeup_thread(mddev->thread);
1829
1830         bitmap_update_sb(bitmap);
1831
1832         if (bitmap->flags & BITMAP_WRITE_ERROR)
1833                 err = -EIO;
1834 out:
1835         return err;
1836 }
1837 EXPORT_SYMBOL_GPL(bitmap_load);
1838
1839 static ssize_t
1840 location_show(struct mddev *mddev, char *page)
1841 {
1842         ssize_t len;
1843         if (mddev->bitmap_info.file)
1844                 len = sprintf(page, "file");
1845         else if (mddev->bitmap_info.offset)
1846                 len = sprintf(page, "%+lld", (long long)mddev->bitmap_info.offset);
1847         else
1848                 len = sprintf(page, "none");
1849         len += sprintf(page+len, "\n");
1850         return len;
1851 }
1852
1853 static ssize_t
1854 location_store(struct mddev *mddev, const char *buf, size_t len)
1855 {
1856
1857         if (mddev->pers) {
1858                 if (!mddev->pers->quiesce)
1859                         return -EBUSY;
1860                 if (mddev->recovery || mddev->sync_thread)
1861                         return -EBUSY;
1862         }
1863
1864         if (mddev->bitmap || mddev->bitmap_info.file ||
1865             mddev->bitmap_info.offset) {
1866                 /* bitmap already configured.  Only option is to clear it */
1867                 if (strncmp(buf, "none", 4) != 0)
1868                         return -EBUSY;
1869                 if (mddev->pers) {
1870                         mddev->pers->quiesce(mddev, 1);
1871                         bitmap_destroy(mddev);
1872                         mddev->pers->quiesce(mddev, 0);
1873                 }
1874                 mddev->bitmap_info.offset = 0;
1875                 if (mddev->bitmap_info.file) {
1876                         struct file *f = mddev->bitmap_info.file;
1877                         mddev->bitmap_info.file = NULL;
1878                         restore_bitmap_write_access(f);
1879                         fput(f);
1880                 }
1881         } else {
1882                 /* No bitmap, OK to set a location */
1883                 long long offset;
1884                 if (strncmp(buf, "none", 4) == 0)
1885                         /* nothing to be done */;
1886                 else if (strncmp(buf, "file:", 5) == 0) {
1887                         /* Not supported yet */
1888                         return -EINVAL;
1889                 } else {
1890                         int rv;
1891                         if (buf[0] == '+')
1892                                 rv = strict_strtoll(buf+1, 10, &offset);
1893                         else
1894                                 rv = strict_strtoll(buf, 10, &offset);
1895                         if (rv)
1896                                 return rv;
1897                         if (offset == 0)
1898                                 return -EINVAL;
1899                         if (mddev->bitmap_info.external == 0 &&
1900                             mddev->major_version == 0 &&
1901                             offset != mddev->bitmap_info.default_offset)
1902                                 return -EINVAL;
1903                         mddev->bitmap_info.offset = offset;
1904                         if (mddev->pers) {
1905                                 mddev->pers->quiesce(mddev, 1);
1906                                 rv = bitmap_create(mddev);
1907                                 if (rv) {
1908                                         bitmap_destroy(mddev);
1909                                         mddev->bitmap_info.offset = 0;
1910                                 }
1911                                 mddev->pers->quiesce(mddev, 0);
1912                                 if (rv)
1913                                         return rv;
1914                         }
1915                 }
1916         }
1917         if (!mddev->external) {
1918                 /* Ensure new bitmap info is stored in
1919                  * metadata promptly.
1920                  */
1921                 set_bit(MD_CHANGE_DEVS, &mddev->flags);
1922                 md_wakeup_thread(mddev->thread);
1923         }
1924         return len;
1925 }
1926
1927 static struct md_sysfs_entry bitmap_location =
1928 __ATTR(location, S_IRUGO|S_IWUSR, location_show, location_store);
1929
1930 static ssize_t
1931 timeout_show(struct mddev *mddev, char *page)
1932 {
1933         ssize_t len;
1934         unsigned long secs = mddev->bitmap_info.daemon_sleep / HZ;
1935         unsigned long jifs = mddev->bitmap_info.daemon_sleep % HZ;
1936
1937         len = sprintf(page, "%lu", secs);
1938         if (jifs)
1939                 len += sprintf(page+len, ".%03u", jiffies_to_msecs(jifs));
1940         len += sprintf(page+len, "\n");
1941         return len;
1942 }
1943
1944 static ssize_t
1945 timeout_store(struct mddev *mddev, const char *buf, size_t len)
1946 {
1947         /* timeout can be set at any time */
1948         unsigned long timeout;
1949         int rv = strict_strtoul_scaled(buf, &timeout, 4);
1950         if (rv)
1951                 return rv;
1952
1953         /* just to make sure we don't overflow... */
1954         if (timeout >= LONG_MAX / HZ)
1955                 return -EINVAL;
1956
1957         timeout = timeout * HZ / 10000;
1958
1959         if (timeout >= MAX_SCHEDULE_TIMEOUT)
1960                 timeout = MAX_SCHEDULE_TIMEOUT-1;
1961         if (timeout < 1)
1962                 timeout = 1;
1963         mddev->bitmap_info.daemon_sleep = timeout;
1964         if (mddev->thread) {
1965                 /* if thread->timeout is MAX_SCHEDULE_TIMEOUT, then
1966                  * the bitmap is all clean and we don't need to
1967                  * adjust the timeout right now
1968                  */
1969                 if (mddev->thread->timeout < MAX_SCHEDULE_TIMEOUT) {
1970                         mddev->thread->timeout = timeout;
1971                         md_wakeup_thread(mddev->thread);
1972                 }
1973         }
1974         return len;
1975 }
1976
1977 static struct md_sysfs_entry bitmap_timeout =
1978 __ATTR(time_base, S_IRUGO|S_IWUSR, timeout_show, timeout_store);
1979
1980 static ssize_t
1981 backlog_show(struct mddev *mddev, char *page)
1982 {
1983         return sprintf(page, "%lu\n", mddev->bitmap_info.max_write_behind);
1984 }
1985
1986 static ssize_t
1987 backlog_store(struct mddev *mddev, const char *buf, size_t len)
1988 {
1989         unsigned long backlog;
1990         int rv = strict_strtoul(buf, 10, &backlog);
1991         if (rv)
1992                 return rv;
1993         if (backlog > COUNTER_MAX)
1994                 return -EINVAL;
1995         mddev->bitmap_info.max_write_behind = backlog;
1996         return len;
1997 }
1998
1999 static struct md_sysfs_entry bitmap_backlog =
2000 __ATTR(backlog, S_IRUGO|S_IWUSR, backlog_show, backlog_store);
2001
2002 static ssize_t
2003 chunksize_show(struct mddev *mddev, char *page)
2004 {
2005         return sprintf(page, "%lu\n", mddev->bitmap_info.chunksize);
2006 }
2007
2008 static ssize_t
2009 chunksize_store(struct mddev *mddev, const char *buf, size_t len)
2010 {
2011         /* Can only be changed when no bitmap is active */
2012         int rv;
2013         unsigned long csize;
2014         if (mddev->bitmap)
2015                 return -EBUSY;
2016         rv = strict_strtoul(buf, 10, &csize);
2017         if (rv)
2018                 return rv;
2019         if (csize < 512 ||
2020             !is_power_of_2(csize))
2021                 return -EINVAL;
2022         mddev->bitmap_info.chunksize = csize;
2023         return len;
2024 }
2025
2026 static struct md_sysfs_entry bitmap_chunksize =
2027 __ATTR(chunksize, S_IRUGO|S_IWUSR, chunksize_show, chunksize_store);
2028
2029 static ssize_t metadata_show(struct mddev *mddev, char *page)
2030 {
2031         return sprintf(page, "%s\n", (mddev->bitmap_info.external
2032                                       ? "external" : "internal"));
2033 }
2034
2035 static ssize_t metadata_store(struct mddev *mddev, const char *buf, size_t len)
2036 {
2037         if (mddev->bitmap ||
2038             mddev->bitmap_info.file ||
2039             mddev->bitmap_info.offset)
2040                 return -EBUSY;
2041         if (strncmp(buf, "external", 8) == 0)
2042                 mddev->bitmap_info.external = 1;
2043         else if (strncmp(buf, "internal", 8) == 0)
2044                 mddev->bitmap_info.external = 0;
2045         else
2046                 return -EINVAL;
2047         return len;
2048 }
2049
2050 static struct md_sysfs_entry bitmap_metadata =
2051 __ATTR(metadata, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
2052
2053 static ssize_t can_clear_show(struct mddev *mddev, char *page)
2054 {
2055         int len;
2056         if (mddev->bitmap)
2057                 len = sprintf(page, "%s\n", (mddev->bitmap->need_sync ?
2058                                              "false" : "true"));
2059         else
2060                 len = sprintf(page, "\n");
2061         return len;
2062 }
2063
2064 static ssize_t can_clear_store(struct mddev *mddev, const char *buf, size_t len)
2065 {
2066         if (mddev->bitmap == NULL)
2067                 return -ENOENT;
2068         if (strncmp(buf, "false", 5) == 0)
2069                 mddev->bitmap->need_sync = 1;
2070         else if (strncmp(buf, "true", 4) == 0) {
2071                 if (mddev->degraded)
2072                         return -EBUSY;
2073                 mddev->bitmap->need_sync = 0;
2074         } else
2075                 return -EINVAL;
2076         return len;
2077 }
2078
2079 static struct md_sysfs_entry bitmap_can_clear =
2080 __ATTR(can_clear, S_IRUGO|S_IWUSR, can_clear_show, can_clear_store);
2081
2082 static ssize_t
2083 behind_writes_used_show(struct mddev *mddev, char *page)
2084 {
2085         if (mddev->bitmap == NULL)
2086                 return sprintf(page, "0\n");
2087         return sprintf(page, "%lu\n",
2088                        mddev->bitmap->behind_writes_used);
2089 }
2090
2091 static ssize_t
2092 behind_writes_used_reset(struct mddev *mddev, const char *buf, size_t len)
2093 {
2094         if (mddev->bitmap)
2095                 mddev->bitmap->behind_writes_used = 0;
2096         return len;
2097 }
2098
2099 static struct md_sysfs_entry max_backlog_used =
2100 __ATTR(max_backlog_used, S_IRUGO | S_IWUSR,
2101        behind_writes_used_show, behind_writes_used_reset);
2102
2103 static struct attribute *md_bitmap_attrs[] = {
2104         &bitmap_location.attr,
2105         &bitmap_timeout.attr,
2106         &bitmap_backlog.attr,
2107         &bitmap_chunksize.attr,
2108         &bitmap_metadata.attr,
2109         &bitmap_can_clear.attr,
2110         &max_backlog_used.attr,
2111         NULL
2112 };
2113 struct attribute_group md_bitmap_group = {
2114         .name = "bitmap",
2115         .attrs = md_bitmap_attrs,
2116 };
2117