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 /* debug macros */
  33
  34 #define DEBUG 0
  35
  36 #if DEBUG
  37 /* these are for debugging purposes only! */
  38
  39 /* define one and only one of these */
  40 #define INJECT_FAULTS_1 0 /* cause bitmap_alloc_page to fail always */
  41 #define INJECT_FAULTS_2 0 /* cause bitmap file to be kicked when first bit set*/
  42 #define INJECT_FAULTS_3 0 /* treat bitmap file as kicked at init time */
  43 #define INJECT_FAULTS_4 0 /* undef */
  44 #define INJECT_FAULTS_5 0 /* undef */
  45 #define INJECT_FAULTS_6 0
  46
  47 /* if these are defined, the driver will fail! debug only */
  48 #define INJECT_FATAL_FAULT_1 0 /* fail kmalloc, causing bitmap_create to fail */
  49 #define INJECT_FATAL_FAULT_2 0 /* undef */
  50 #define INJECT_FATAL_FAULT_3 0 /* undef */
  51 #endif
  52
  53 #ifndef PRINTK
  54 #  if DEBUG > 0
  55 #    define PRINTK(x...) printk(KERN_DEBUG x)
  56 #  else
  57 #    define PRINTK(x...)
  58 #  endif
  59 #endif
  60
  61 static inline char *bmname(struct bitmap *bitmap)
  62 {
  63         return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
  64 }
  65
  66 /*
  67  * just a placeholder - calls kmalloc for bitmap pages
  68  */
  69 static unsigned char *bitmap_alloc_page(struct bitmap *bitmap)
  70 {
  71         unsigned char *page;
  72
  73 #ifdef INJECT_FAULTS_1
  74         page = NULL;
  75 #else
  76         page = kzalloc(PAGE_SIZE, GFP_NOIO);
  77 #endif
  78         if (!page)
  79                 printk("%s: bitmap_alloc_page FAILED\n", bmname(bitmap));
  80         else
  81                 PRINTK("%s: bitmap_alloc_page: allocated page at %p\n",
  82                         bmname(bitmap), page);
  83         return page;
  84 }
  85
  86 /*
  87  * for now just a placeholder -- just calls kfree for bitmap pages
  88  */
  89 static void bitmap_free_page(struct bitmap *bitmap, unsigned char *page)
  90 {
  91         PRINTK("%s: bitmap_free_page: free page %p\n", bmname(bitmap), page);
  92         kfree(page);
  93 }
  94
  95 /*
  96  * check a page and, if necessary, allocate it (or hijack it if the alloc fails)
  97  *
  98  * 1) check to see if this page is allocated, if it's not then try to alloc
  99  * 2) if the alloc fails, set the page's hijacked flag so we'll use the
 100  *    page pointer directly as a counter
 101  *
 102  * if we find our page, we increment the page's refcount so that it stays
 103  * allocated while we're using it
 104  */
 105 static int bitmap_checkpage(struct bitmap *bitmap,
 106                             unsigned long page, int create)
 107 __releases(bitmap->lock)
 108 __acquires(bitmap->lock)
 109 {
 110         unsigned char *mappage;
 111
 112         if (page >= bitmap->pages) {
 113                 /* This can happen if bitmap_start_sync goes beyond
 114                  * End-of-device while looking for a whole page.
 115                  * It is harmless.
 116                  */
 117                 return -EINVAL;
 118         }
 119
 120         if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
 121                 return 0;
 122
 123         if (bitmap->bp[page].map) /* page is already allocated, just return */
 124                 return 0;
 125
 126         if (!create)
 127                 return -ENOENT;
 128
 129         /* this page has not been allocated yet */
 130
 131         spin_unlock_irq(&bitmap->lock);
 132         mappage = bitmap_alloc_page(bitmap);
 133         spin_lock_irq(&bitmap->lock);
 134
 135         if (mappage == NULL) {
 136                 PRINTK("%s: bitmap map page allocation failed, hijacking\n",
 137                         bmname(bitmap));
 138                 /* failed - set the hijacked flag so that we can use the
 139                  * pointer as a counter */
 140                 if (!bitmap->bp[page].map)
 141                         bitmap->bp[page].hijacked = 1;
 142         } else if (bitmap->bp[page].map ||
 143                    bitmap->bp[page].hijacked) {
 144                 /* somebody beat us to getting the page */
 145                 bitmap_free_page(bitmap, mappage);
 146                 return 0;
 147         } else {
 148
 149                 /* no page was in place and we have one, so install it */
 150
 151                 bitmap->bp[page].map = mappage;
 152                 bitmap->missing_pages--;
 153         }
 154         return 0;
 155 }
 156
 157 /* if page is completely empty, put it back on the free list, or dealloc it */
 158 /* if page was hijacked, unmark the flag so it might get alloced next time */
 159 /* Note: lock should be held when calling this */
 160 static void bitmap_checkfree(struct bitmap *bitmap, unsigned long page)
 161 {
 162         char *ptr;
 163
 164         if (bitmap->bp[page].count) /* page is still busy */
 165                 return;
 166
 167         /* page is no longer in use, it can be released */
 168
 169         if (bitmap->bp[page].hijacked) { /* page was hijacked, undo this now */
 170                 bitmap->bp[page].hijacked = 0;
 171                 bitmap->bp[page].map = NULL;
 172         } else {
 173                 /* normal case, free the page */
 174                 ptr = bitmap->bp[page].map;
 175                 bitmap->bp[page].map = NULL;
 176                 bitmap->missing_pages++;
 177                 bitmap_free_page(bitmap, ptr);
 178         }
 179 }
 180
 181 /*
 182  * bitmap file handling - read and write the bitmap file and its superblock
 183  */
 184
 185 /*
 186  * basic page I/O operations
 187  */
 188
 189 /* IO operations when bitmap is stored near all superblocks */
 190 static struct page *read_sb_page(mddev_t *mddev, loff_t offset,
 191                                  struct page *page,
 192                                  unsigned long index, int size)
 193 {
 194         /* choose a good rdev and read the page from there */
 195
 196         mdk_rdev_t *rdev;
 197         sector_t target;
 198         int did_alloc = 0;
 199
 200         if (!page) {
 201                 page = alloc_page(GFP_KERNEL);
 202                 if (!page)
 203                         return ERR_PTR(-ENOMEM);
 204                 did_alloc = 1;
 205         }
 206
 207         list_for_each_entry(rdev, &mddev->disks, same_set) {
 208                 if (! test_bit(In_sync, &rdev->flags)
 209                     || test_bit(Faulty, &rdev->flags))
 210                         continue;
 211
 212                 target = offset + index * (PAGE_SIZE/512);
 213
 214                 if (sync_page_io(rdev, target,
 215                                  roundup(size, bdev_logical_block_size(rdev->bdev)),
 216                                  page, READ, true)) {
 217                         page->index = index;
 218                         attach_page_buffers(page, NULL); /* so that free_buffer will
 219                                                           * quietly no-op */
 220                         return page;
 221                 }
 222         }
 223         if (did_alloc)
 224                 put_page(page);
 225         return ERR_PTR(-EIO);
 226
 227 }
 228
 229 static mdk_rdev_t *next_active_rdev(mdk_rdev_t *rdev, mddev_t *mddev)
 230 {
 231         /* Iterate the disks of an mddev, using rcu to protect access to the
 232          * linked list, and raising the refcount of devices we return to ensure
 233          * they don't disappear while in use.
 234          * As devices are only added or removed when raid_disk is < 0 and
 235          * nr_pending is 0 and In_sync is clear, the entries we return will
 236          * still be in the same position on the list when we re-enter
 237          * list_for_each_continue_rcu.
 238          */
 239         struct list_head *pos;
 240         rcu_read_lock();
 241         if (rdev == NULL)
 242                 /* start at the beginning */
 243                 pos = &mddev->disks;
 244         else {
 245                 /* release the previous rdev and start from there. */
 246                 rdev_dec_pending(rdev, mddev);
 247                 pos = &rdev->same_set;
 248         }
 249         list_for_each_continue_rcu(pos, &mddev->disks) {
 250                 rdev = list_entry(pos, mdk_rdev_t, same_set);
 251                 if (rdev->raid_disk >= 0 &&
 252                     !test_bit(Faulty, &rdev->flags)) {
 253                         /* this is a usable devices */
 254                         atomic_inc(&rdev->nr_pending);
 255                         rcu_read_unlock();
 256                         return rdev;
 257                 }
 258         }
 259         rcu_read_unlock();
 260         return NULL;
 261 }
 262
 263 static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
 264 {
 265         mdk_rdev_t *rdev = NULL;
 266         struct block_device *bdev;
 267         mddev_t *mddev = bitmap->mddev;
 268
 269         while ((rdev = next_active_rdev(rdev, mddev)) != NULL) {
 270                 int size = PAGE_SIZE;
 271                 loff_t offset = mddev->bitmap_info.offset;
 272
 273                 bdev = (rdev->meta_bdev) ? rdev->meta_bdev : rdev->bdev;
 274
 275                 if (page->index == bitmap->file_pages-1)
 276                         size = roundup(bitmap->last_page_size,
 277                                        bdev_logical_block_size(bdev));
 278                 /* Just make sure we aren't corrupting data or
 279                  * metadata
 280                  */
 281                 if (mddev->external) {
 282                         /* Bitmap could be anywhere. */
 283                         if (rdev->sb_start + offset + (page->index
 284                                                        * (PAGE_SIZE/512))
 285                             > rdev->data_offset
 286                             &&
 287                             rdev->sb_start + offset
 288                             < (rdev->data_offset + mddev->dev_sectors
 289                              + (PAGE_SIZE/512)))
 290                                 goto bad_alignment;
 291                 } else if (offset < 0) {
 292                         /* DATA  BITMAP METADATA  */
 293                         if (offset
 294                             + (long)(page->index * (PAGE_SIZE/512))
 295                             + size/512 > 0)
 296                                 /* bitmap runs in to metadata */
 297                                 goto bad_alignment;
 298                         if (rdev->data_offset + mddev->dev_sectors
 299                             > rdev->sb_start + offset)
 300                                 /* data runs in to bitmap */
 301                                 goto bad_alignment;
 302                 } else if (rdev->sb_start < rdev->data_offset) {
 303                         /* METADATA BITMAP DATA */
 304                         if (rdev->sb_start
 305                             + offset
 306                             + page->index*(PAGE_SIZE/512) + size/512
 307                             > rdev->data_offset)
 308                                 /* bitmap runs in to data */
 309                                 goto bad_alignment;
 310                 } else {
 311                         /* DATA METADATA BITMAP - no problems */
 312                 }
 313                 md_super_write(mddev, rdev,
 314                                rdev->sb_start + offset
 315                                + page->index * (PAGE_SIZE/512),
 316                                size,
 317                                page);
 318         }
 319
 320         if (wait)
 321                 md_super_wait(mddev);
 322         return 0;
 323
 324  bad_alignment:
 325         return -EINVAL;
 326 }
 327
 328 static void bitmap_file_kick(struct bitmap *bitmap);
 329 /*
 330  * write out a page to a file
 331  */
 332 static void write_page(struct bitmap *bitmap, struct page *page, int wait)
 333 {
 334         struct buffer_head *bh;
 335
 336         if (bitmap->file == NULL) {
 337                 switch (write_sb_page(bitmap, page, wait)) {
 338                 case -EINVAL:
 339                         bitmap->flags |= BITMAP_WRITE_ERROR;
 340                 }
 341         } else {
 342
 343                 bh = page_buffers(page);
 344
 345                 while (bh && bh->b_blocknr) {
 346                         atomic_inc(&bitmap->pending_writes);
 347                         set_buffer_locked(bh);
 348                         set_buffer_mapped(bh);
 349                         submit_bh(WRITE | REQ_SYNC, bh);
 350                         bh = bh->b_this_page;
 351                 }
 352
 353                 if (wait)
 354                         wait_event(bitmap->write_wait,
 355                                    atomic_read(&bitmap->pending_writes)==0);
 356         }
 357         if (bitmap->flags & BITMAP_WRITE_ERROR)
 358                 bitmap_file_kick(bitmap);
 359 }
 360
 361 static void end_bitmap_write(struct buffer_head *bh, int uptodate)
 362 {
 363         struct bitmap *bitmap = bh->b_private;
 364         unsigned long flags;
 365
 366         if (!uptodate) {
 367                 spin_lock_irqsave(&bitmap->lock, flags);
 368                 bitmap->flags |= BITMAP_WRITE_ERROR;
 369                 spin_unlock_irqrestore(&bitmap->lock, flags);
 370         }
 371         if (atomic_dec_and_test(&bitmap->pending_writes))
 372                 wake_up(&bitmap->write_wait);
 373 }
 374
 375 /* copied from buffer.c */
 376 static void
 377 __clear_page_buffers(struct page *page)
 378 {
 379         ClearPagePrivate(page);
 380         set_page_private(page, 0);
 381         page_cache_release(page);
 382 }
 383 static void free_buffers(struct page *page)
 384 {
 385         struct buffer_head *bh = page_buffers(page);
 386
 387         while (bh) {
 388                 struct buffer_head *next = bh->b_this_page;
 389                 free_buffer_head(bh);
 390                 bh = next;
 391         }
 392         __clear_page_buffers(page);
 393         put_page(page);
 394 }
 395
 396 /* read a page from a file.
 397  * We both read the page, and attach buffers to the page to record the
 398  * address of each block (using bmap).  These addresses will be used
 399  * to write the block later, completely bypassing the filesystem.
 400  * This usage is similar to how swap files are handled, and allows us
 401  * to write to a file with no concerns of memory allocation failing.
 402  */
 403 static struct page *read_page(struct file *file, unsigned long index,
 404                               struct bitmap *bitmap,
 405                               unsigned long count)
 406 {
 407         struct page *page = NULL;
 408         struct inode *inode = file->f_path.dentry->d_inode;
 409         struct buffer_head *bh;
 410         sector_t block;
 411
 412         PRINTK("read bitmap file (%dB @ %llu)\n", (int)PAGE_SIZE,
 413                         (unsigned long long)index << PAGE_SHIFT);
 414
 415         page = alloc_page(GFP_KERNEL);
 416         if (!page)
 417                 page = ERR_PTR(-ENOMEM);
 418         if (IS_ERR(page))
 419                 goto out;
 420
 421         bh = alloc_page_buffers(page, 1<<inode->i_blkbits, 0);
 422         if (!bh) {
 423                 put_page(page);
 424                 page = ERR_PTR(-ENOMEM);
 425                 goto out;
 426         }
 427         attach_page_buffers(page, bh);
 428         block = index << (PAGE_SHIFT - inode->i_blkbits);
 429         while (bh) {
 430                 if (count == 0)
 431                         bh->b_blocknr = 0;
 432                 else {
 433                         bh->b_blocknr = bmap(inode, block);
 434                         if (bh->b_blocknr == 0) {
 435                                 /* Cannot use this file! */
 436                                 free_buffers(page);
 437                                 page = ERR_PTR(-EINVAL);
 438                                 goto out;
 439                         }
 440                         bh->b_bdev = inode->i_sb->s_bdev;
 441                         if (count < (1<<inode->i_blkbits))
 442                                 count = 0;
 443                         else
 444                                 count -= (1<<inode->i_blkbits);
 445
 446                         bh->b_end_io = end_bitmap_write;
 447                         bh->b_private = bitmap;
 448                         atomic_inc(&bitmap->pending_writes);
 449                         set_buffer_locked(bh);
 450                         set_buffer_mapped(bh);
 451                         submit_bh(READ, bh);
 452                 }
 453                 block++;
 454                 bh = bh->b_this_page;
 455         }
 456         page->index = index;
 457
 458         wait_event(bitmap->write_wait,
 459                    atomic_read(&bitmap->pending_writes)==0);
 460         if (bitmap->flags & BITMAP_WRITE_ERROR) {
 461                 free_buffers(page);
 462                 page = ERR_PTR(-EIO);
 463         }
 464 out:
 465         if (IS_ERR(page))
 466                 printk(KERN_ALERT "md: bitmap read error: (%dB @ %llu): %ld\n",
 467                         (int)PAGE_SIZE,
 468                         (unsigned long long)index << PAGE_SHIFT,
 469                         PTR_ERR(page));
 470         return page;
 471 }
 472
 473 /*
 474  * bitmap file superblock operations
 475  */
 476
 477 /* update the event counter and sync the superblock to disk */
 478 void bitmap_update_sb(struct bitmap *bitmap)
 479 {
 480         bitmap_super_t *sb;
 481         unsigned long flags;
 482
 483         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
 484                 return;
 485         if (bitmap->mddev->bitmap_info.external)
 486                 return;
 487         spin_lock_irqsave(&bitmap->lock, flags);
 488         if (!bitmap->sb_page) { /* no superblock */
 489                 spin_unlock_irqrestore(&bitmap->lock, flags);
 490                 return;
 491         }
 492         spin_unlock_irqrestore(&bitmap->lock, flags);
 493         sb = kmap_atomic(bitmap->sb_page, KM_USER0);
 494         sb->events = cpu_to_le64(bitmap->mddev->events);
 495         if (bitmap->mddev->events < bitmap->events_cleared)
 496                 /* rocking back to read-only */
 497                 bitmap->events_cleared = bitmap->mddev->events;
 498         sb->events_cleared = cpu_to_le64(bitmap->events_cleared);
 499         sb->state = cpu_to_le32(bitmap->flags);
 500         /* Just in case these have been changed via sysfs: */
 501         sb->daemon_sleep = cpu_to_le32(bitmap->mddev->bitmap_info.daemon_sleep/HZ);
 502         sb->write_behind = cpu_to_le32(bitmap->mddev->bitmap_info.max_write_behind);
 503         kunmap_atomic(sb, KM_USER0);
 504         write_page(bitmap, bitmap->sb_page, 1);
 505 }
 506
 507 /* print out the bitmap file superblock */
 508 void bitmap_print_sb(struct bitmap *bitmap)
 509 {
 510         bitmap_super_t *sb;
 511
 512         if (!bitmap || !bitmap->sb_page)
 513                 return;
 514         sb = kmap_atomic(bitmap->sb_page, KM_USER0);
 515         printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
 516         printk(KERN_DEBUG "         magic: %08x\n", le32_to_cpu(sb->magic));
 517         printk(KERN_DEBUG "       version: %d\n", le32_to_cpu(sb->version));
 518         printk(KERN_DEBUG "          uuid: %08x.%08x.%08x.%08x\n",
 519                                         *(__u32 *)(sb->uuid+0),
 520                                         *(__u32 *)(sb->uuid+4),
 521                                         *(__u32 *)(sb->uuid+8),
 522                                         *(__u32 *)(sb->uuid+12));
 523         printk(KERN_DEBUG "        events: %llu\n",
 524                         (unsigned long long) le64_to_cpu(sb->events));
 525         printk(KERN_DEBUG "events cleared: %llu\n",
 526                         (unsigned long long) le64_to_cpu(sb->events_cleared));
 527         printk(KERN_DEBUG "         state: %08x\n", le32_to_cpu(sb->state));
 528         printk(KERN_DEBUG "     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
 529         printk(KERN_DEBUG "  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
 530         printk(KERN_DEBUG "     sync size: %llu KB\n",
 531                         (unsigned long long)le64_to_cpu(sb->sync_size)/2);
 532         printk(KERN_DEBUG "max write behind: %d\n", le32_to_cpu(sb->write_behind));
 533         kunmap_atomic(sb, KM_USER0);
 534 }
 535
 536 /*
 537  * bitmap_new_disk_sb
 538  * @bitmap
 539  *
 540  * This function is somewhat the reverse of bitmap_read_sb.  bitmap_read_sb
 541  * reads and verifies the on-disk bitmap superblock and populates bitmap_info.
 542  * This function verifies 'bitmap_info' and populates the on-disk bitmap
 543  * structure, which is to be written to disk.
 544  *
 545  * Returns: 0 on success, -Exxx on error
 546  */
 547 static int bitmap_new_disk_sb(struct bitmap *bitmap)
 548 {
 549         bitmap_super_t *sb;
 550         unsigned long chunksize, daemon_sleep, write_behind;
 551         int err = -EINVAL;
 552
 553         bitmap->sb_page = alloc_page(GFP_KERNEL);
 554         if (IS_ERR(bitmap->sb_page)) {
 555                 err = PTR_ERR(bitmap->sb_page);
 556                 bitmap->sb_page = NULL;
 557                 return err;
 558         }
 559         bitmap->sb_page->index = 0;
 560
 561         sb = kmap_atomic(bitmap->sb_page, KM_USER0);
 562
 563         sb->magic = cpu_to_le32(BITMAP_MAGIC);
 564         sb->version = cpu_to_le32(BITMAP_MAJOR_HI);
 565
 566         chunksize = bitmap->mddev->bitmap_info.chunksize;
 567         BUG_ON(!chunksize);
 568         if (!is_power_of_2(chunksize)) {
 569                 kunmap_atomic(sb, KM_USER0);
 570                 printk(KERN_ERR "bitmap chunksize not a power of 2\n");
 571                 return -EINVAL;
 572         }
 573         sb->chunksize = cpu_to_le32(chunksize);
 574
 575         daemon_sleep = bitmap->mddev->bitmap_info.daemon_sleep;
 576         if (!daemon_sleep ||
 577             (daemon_sleep < 1) || (daemon_sleep > MAX_SCHEDULE_TIMEOUT)) {
 578                 printk(KERN_INFO "Choosing daemon_sleep default (5 sec)\n");
 579                 daemon_sleep = 5 * HZ;
 580         }
 581         sb->daemon_sleep = cpu_to_le32(daemon_sleep);
 582         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 583
 584         /*
 585          * FIXME: write_behind for RAID1.  If not specified, what
 586          * is a good choice?  We choose COUNTER_MAX / 2 arbitrarily.
 587          */
 588         write_behind = bitmap->mddev->bitmap_info.max_write_behind;
 589         if (write_behind > COUNTER_MAX)
 590                 write_behind = COUNTER_MAX / 2;
 591         sb->write_behind = cpu_to_le32(write_behind);
 592         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 593
 594         /* keep the array size field of the bitmap superblock up to date */
 595         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 596
 597         memcpy(sb->uuid, bitmap->mddev->uuid, 16);
 598
 599         bitmap->flags |= BITMAP_STALE;
 600         sb->state |= cpu_to_le32(BITMAP_STALE);
 601         bitmap->events_cleared = bitmap->mddev->events;
 602         sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
 603
 604         bitmap->flags |= BITMAP_HOSTENDIAN;
 605         sb->version = cpu_to_le32(BITMAP_MAJOR_HOSTENDIAN);
 606
 607         kunmap_atomic(sb, KM_USER0);
 608
 609         return 0;
 610 }
 611
 612 /* read the superblock from the bitmap file and initialize some bitmap fields */
 613 static int bitmap_read_sb(struct bitmap *bitmap)
 614 {
 615         char *reason = NULL;
 616         bitmap_super_t *sb;
 617         unsigned long chunksize, daemon_sleep, write_behind;
 618         unsigned long long events;
 619         int err = -EINVAL;
 620
 621         /* page 0 is the superblock, read it... */
 622         if (bitmap->file) {
 623                 loff_t isize = i_size_read(bitmap->file->f_mapping->host);
 624                 int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
 625
 626                 bitmap->sb_page = read_page(bitmap->file, 0, bitmap, bytes);
 627         } else {
 628                 bitmap->sb_page = read_sb_page(bitmap->mddev,
 629                                                bitmap->mddev->bitmap_info.offset,
 630                                                NULL,
 631                                                0, sizeof(bitmap_super_t));
 632         }
 633         if (IS_ERR(bitmap->sb_page)) {
 634                 err = PTR_ERR(bitmap->sb_page);
 635                 bitmap->sb_page = NULL;
 636                 return err;
 637         }
 638
 639         sb = kmap_atomic(bitmap->sb_page, KM_USER0);
 640
 641         chunksize = le32_to_cpu(sb->chunksize);
 642         daemon_sleep = le32_to_cpu(sb->daemon_sleep) * HZ;
 643         write_behind = le32_to_cpu(sb->write_behind);
 644
 645         /* verify that the bitmap-specific fields are valid */
 646         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
 647                 reason = "bad magic";
 648         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
 649                  le32_to_cpu(sb->version) > BITMAP_MAJOR_HI)
 650                 reason = "unrecognized superblock version";
 651         else if (chunksize < 512)
 652                 reason = "bitmap chunksize too small";
 653         else if (!is_power_of_2(chunksize))
 654                 reason = "bitmap chunksize not a power of 2";
 655         else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT)
 656                 reason = "daemon sleep period out of range";
 657         else if (write_behind > COUNTER_MAX)
 658                 reason = "write-behind limit out of range (0 - 16383)";
 659         if (reason) {
 660                 printk(KERN_INFO "%s: invalid bitmap file superblock: %s\n",
 661                         bmname(bitmap), reason);
 662                 goto out;
 663         }
 664
 665         /* keep the array size field of the bitmap superblock up to date */
 666         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 667
 668         if (!bitmap->mddev->persistent)
 669                 goto success;
 670
 671         /*
 672          * if we have a persistent array superblock, compare the
 673          * bitmap's UUID and event counter to the mddev's
 674          */
 675         if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
 676                 printk(KERN_INFO "%s: bitmap superblock UUID mismatch\n",
 677                         bmname(bitmap));
 678                 goto out;
 679         }
 680         events = le64_to_cpu(sb->events);
 681         if (events < bitmap->mddev->events) {
 682                 printk(KERN_INFO "%s: bitmap file is out of date (%llu < %llu) "
 683                         "-- forcing full recovery\n", bmname(bitmap), events,
 684                         (unsigned long long) bitmap->mddev->events);
 685                 sb->state |= cpu_to_le32(BITMAP_STALE);
 686         }
 687 success:
 688         /* assign fields using values from superblock */
 689         bitmap->mddev->bitmap_info.chunksize = chunksize;
 690         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 691         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 692         bitmap->flags |= le32_to_cpu(sb->state);
 693         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
 694                 bitmap->flags |= BITMAP_HOSTENDIAN;
 695         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
 696         if (bitmap->flags & BITMAP_STALE)
 697                 bitmap->events_cleared = bitmap->mddev->events;
 698         err = 0;
 699 out:
 700         kunmap_atomic(sb, KM_USER0);
 701         if (err)
 702                 bitmap_print_sb(bitmap);
 703         return err;
 704 }
 705
 706 enum bitmap_mask_op {
 707         MASK_SET,
 708         MASK_UNSET
 709 };
 710
 711 /* record the state of the bitmap in the superblock.  Return the old value */
 712 static int bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
 713                              enum bitmap_mask_op op)
 714 {
 715         bitmap_super_t *sb;
 716         unsigned long flags;
 717         int old;
 718
 719         spin_lock_irqsave(&bitmap->lock, flags);
 720         if (!bitmap->sb_page) { /* can't set the state */
 721                 spin_unlock_irqrestore(&bitmap->lock, flags);
 722                 return 0;
 723         }
 724         spin_unlock_irqrestore(&bitmap->lock, flags);
 725         sb = kmap_atomic(bitmap->sb_page, KM_USER0);
 726         old = le32_to_cpu(sb->state) & bits;
 727         switch (op) {
 728         case MASK_SET:
 729                 sb->state |= cpu_to_le32(bits);
 730                 bitmap->flags |= bits;
 731                 break;
 732         case MASK_UNSET:
 733                 sb->state &= cpu_to_le32(~bits);
 734                 bitmap->flags &= ~bits;
 735                 break;
 736         default:
 737                 BUG();
 738         }
 739         kunmap_atomic(sb, KM_USER0);
 740         return old;
 741 }
 742
 743 /*
 744  * general bitmap file operations
 745  */
 746
 747 /*
 748  * on-disk bitmap:
 749  *
 750  * Use one bit per "chunk" (block set). We do the disk I/O on the bitmap
 751  * file a page at a time. There's a superblock at the start of the file.
 752  */
 753 /* calculate the index of the page that contains this bit */
 754 static inline unsigned long file_page_index(struct bitmap *bitmap, unsigned long chunk)
 755 {
 756         if (!bitmap->mddev->bitmap_info.external)
 757                 chunk += sizeof(bitmap_super_t) << 3;
 758         return chunk >> PAGE_BIT_SHIFT;
 759 }
 760
 761 /* calculate the (bit) offset of this bit within a page */
 762 static inline unsigned long file_page_offset(struct bitmap *bitmap, unsigned long chunk)
 763 {
 764         if (!bitmap->mddev->bitmap_info.external)
 765                 chunk += sizeof(bitmap_super_t) << 3;
 766         return chunk & (PAGE_BITS - 1);
 767 }
 768
 769 /*
 770  * return a pointer to the page in the filemap that contains the given bit
 771  *
 772  * this lookup is complicated by the fact that the bitmap sb might be exactly
 773  * 1 page (e.g., x86) or less than 1 page -- so the bitmap might start on page
 774  * 0 or page 1
 775  */
 776 static inline struct page *filemap_get_page(struct bitmap *bitmap,
 777                                             unsigned long chunk)
 778 {
 779         if (file_page_index(bitmap, chunk) >= bitmap->file_pages)
 780                 return NULL;
 781         return bitmap->filemap[file_page_index(bitmap, chunk)
 782                                - file_page_index(bitmap, 0)];
 783 }
 784
 785 static void bitmap_file_unmap(struct bitmap *bitmap)
 786 {
 787         struct page **map, *sb_page;
 788         unsigned long *attr;
 789         int pages;
 790         unsigned long flags;
 791
 792         spin_lock_irqsave(&bitmap->lock, flags);
 793         map = bitmap->filemap;
 794         bitmap->filemap = NULL;
 795         attr = bitmap->filemap_attr;
 796         bitmap->filemap_attr = NULL;
 797         pages = bitmap->file_pages;
 798         bitmap->file_pages = 0;
 799         sb_page = bitmap->sb_page;
 800         bitmap->sb_page = NULL;
 801         spin_unlock_irqrestore(&bitmap->lock, flags);
 802
 803         while (pages--)
 804                 if (map[pages] != sb_page) /* 0 is sb_page, release it below */
 805                         free_buffers(map[pages]);
 806         kfree(map);
 807         kfree(attr);
 808
 809         if (sb_page)
 810                 free_buffers(sb_page);
 811 }
 812
 813 static void bitmap_file_put(struct bitmap *bitmap)
 814 {
 815         struct file *file;
 816         unsigned long flags;
 817
 818         spin_lock_irqsave(&bitmap->lock, flags);
 819         file = bitmap->file;
 820         bitmap->file = NULL;
 821         spin_unlock_irqrestore(&bitmap->lock, flags);
 822
 823         if (file)
 824                 wait_event(bitmap->write_wait,
 825                            atomic_read(&bitmap->pending_writes)==0);
 826         bitmap_file_unmap(bitmap);
 827
 828         if (file) {
 829                 struct inode *inode = file->f_path.dentry->d_inode;
 830                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
 831                 fput(file);
 832         }
 833 }
 834
 835 /*
 836  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
 837  * then it is no longer reliable, so we stop using it and we mark the file
 838  * as failed in the superblock
 839  */
 840 static void bitmap_file_kick(struct bitmap *bitmap)
 841 {
 842         char *path, *ptr = NULL;
 843
 844         if (bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET) == 0) {
 845                 bitmap_update_sb(bitmap);
 846
 847                 if (bitmap->file) {
 848                         path = kmalloc(PAGE_SIZE, GFP_KERNEL);
 849                         if (path)
 850                                 ptr = d_path(&bitmap->file->f_path, path,
 851                                              PAGE_SIZE);
 852
 853                         printk(KERN_ALERT
 854                               "%s: kicking failed bitmap file %s from array!\n",
 855                               bmname(bitmap), IS_ERR(ptr) ? "" : ptr);
 856
 857                         kfree(path);
 858                 } else
 859                         printk(KERN_ALERT
 860                                "%s: disabling internal bitmap due to errors\n",
 861                                bmname(bitmap));
 862         }
 863
 864         bitmap_file_put(bitmap);
 865
 866         return;
 867 }
 868
 869 enum bitmap_page_attr {
 870         BITMAP_PAGE_DIRTY = 0,     /* there are set bits that need to be synced */
 871         BITMAP_PAGE_CLEAN = 1,     /* there are bits that might need to be cleared */
 872         BITMAP_PAGE_NEEDWRITE = 2, /* there are cleared bits that need to be synced */
 873 };
 874
 875 static inline void set_page_attr(struct bitmap *bitmap, struct page *page,
 876                                 enum bitmap_page_attr attr)
 877 {
 878         __set_bit((page->index<<2) + attr, bitmap->filemap_attr);
 879 }
 880
 881 static inline void clear_page_attr(struct bitmap *bitmap, struct page *page,
 882                                 enum bitmap_page_attr attr)
 883 {
 884         __clear_bit((page->index<<2) + attr, bitmap->filemap_attr);
 885 }
 886
 887 static inline unsigned long test_page_attr(struct bitmap *bitmap, struct page *page,
 888                                            enum bitmap_page_attr attr)
 889 {
 890         return test_bit((page->index<<2) + attr, bitmap->filemap_attr);
 891 }
 892
 893 /*
 894  * bitmap_file_set_bit -- called before performing a write to the md device
 895  * to set (and eventually sync) a particular bit in the bitmap file
 896  *
 897  * we set the bit immediately, then we record the page number so that
 898  * when an unplug occurs, we can flush the dirty pages out to disk
 899  */
 900 static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 901 {
 902         unsigned long bit;
 903         struct page *page;
 904         void *kaddr;
 905         unsigned long chunk = block >> CHUNK_BLOCK_SHIFT(bitmap);
 906
 907         if (!bitmap->filemap)
 908                 return;
 909
 910         page = filemap_get_page(bitmap, chunk);
 911         if (!page)
 912                 return;
 913         bit = file_page_offset(bitmap, chunk);
 914
 915         /* set the bit */
 916         kaddr = kmap_atomic(page, KM_USER0);
 917         if (bitmap->flags & BITMAP_HOSTENDIAN)
 918                 set_bit(bit, kaddr);
 919         else
 920                 __set_bit_le(bit, kaddr);
 921         kunmap_atomic(kaddr, KM_USER0);
 922         PRINTK("set file bit %lu page %lu\n", bit, page->index);
 923         /* record page number so it gets flushed to disk when unplug occurs */
 924         set_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 925 }
 926
 927 /* this gets called when the md device is ready to unplug its underlying
 928  * (slave) device queues -- before we let any writes go down, we need to
 929  * sync the dirty pages of the bitmap file to disk */
 930 void bitmap_unplug(struct bitmap *bitmap)
 931 {
 932         unsigned long i, flags;
 933         int dirty, need_write;
 934         struct page *page;
 935         int wait = 0;
 936
 937         if (!bitmap)
 938                 return;
 939
 940         /* look at each page to see if there are any set bits that need to be
 941          * flushed out to disk */
 942         for (i = 0; i < bitmap->file_pages; i++) {
 943                 spin_lock_irqsave(&bitmap->lock, flags);
 944                 if (!bitmap->filemap) {
 945                         spin_unlock_irqrestore(&bitmap->lock, flags);
 946                         return;
 947                 }
 948                 page = bitmap->filemap[i];
 949                 dirty = test_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 950                 need_write = test_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 951                 clear_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 952                 clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 953                 if (dirty)
 954                         wait = 1;
 955                 spin_unlock_irqrestore(&bitmap->lock, flags);
 956
 957                 if (dirty || need_write)
 958                         write_page(bitmap, page, 0);
 959         }
 960         if (wait) { /* if any writes were performed, we need to wait on them */
 961                 if (bitmap->file)
 962                         wait_event(bitmap->write_wait,
 963                                    atomic_read(&bitmap->pending_writes)==0);
 964                 else
 965                         md_super_wait(bitmap->mddev);
 966         }
 967         if (bitmap->flags & BITMAP_WRITE_ERROR)
 968                 bitmap_file_kick(bitmap);
 969 }
 970 EXPORT_SYMBOL(bitmap_unplug);
 971
 972 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
 973 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
 974  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
 975  * memory mapping of the bitmap file
 976  * Special cases:
 977  *   if there's no bitmap file, or if the bitmap file had been
 978  *   previously kicked from the array, we mark all the bits as
 979  *   1's in order to cause a full resync.
 980  *
 981  * We ignore all bits for sectors that end earlier than 'start'.
 982  * This is used when reading an out-of-date bitmap...
 983  */
 984 static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
 985 {
 986         unsigned long i, chunks, index, oldindex, bit;
 987         struct page *page = NULL, *oldpage = NULL;
 988         unsigned long num_pages, bit_cnt = 0;
 989         struct file *file;
 990         unsigned long bytes, offset;
 991         int outofdate;
 992         int ret = -ENOSPC;
 993         void *paddr;
 994
 995         chunks = bitmap->chunks;
 996         file = bitmap->file;
 997
 998         BUG_ON(!file && !bitmap->mddev->bitmap_info.offset);
 999
1000 #ifdef INJECT_FAULTS_3
1001         outofdate = 1;
1002 #else
1003         outofdate = bitmap->flags & BITMAP_STALE;
1004 #endif
1005         if (outofdate)
1006                 printk(KERN_INFO "%s: bitmap file is out of date, doing full "
1007                         "recovery\n", bmname(bitmap));
1008
1009         bytes = DIV_ROUND_UP(bitmap->chunks, 8);
1010         if (!bitmap->mddev->bitmap_info.external)
1011                 bytes += sizeof(bitmap_super_t);
1012
1013         num_pages = DIV_ROUND_UP(bytes, PAGE_SIZE);
1014
1015         if (file && i_size_read(file->f_mapping->host) < bytes) {
1016                 printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
1017                         bmname(bitmap),
1018                         (unsigned long) i_size_read(file->f_mapping->host),
1019                         bytes);
1020                 goto err;
1021         }
1022
1023         ret = -ENOMEM;
1024
1025         bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
1026         if (!bitmap->filemap)
1027                 goto err;
1028
1029         /* We need 4 bits per page, rounded up to a multiple of sizeof(unsigned long) */
1030         bitmap->filemap_attr = kzalloc(
1031                 roundup(DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
1032                 GFP_KERNEL);
1033         if (!bitmap->filemap_attr)
1034                 goto err;
1035
1036         oldindex = ~0L;
1037
1038         for (i = 0; i < chunks; i++) {
1039                 int b;
1040                 index = file_page_index(bitmap, i);
1041                 bit = file_page_offset(bitmap, i);
1042                 if (index != oldindex) { /* this is a new page, read it in */
1043                         int count;
1044                         /* unmap the old page, we're done with it */
1045                         if (index == num_pages-1)
1046                                 count = bytes - index * PAGE_SIZE;
1047                         else
1048                                 count = PAGE_SIZE;
1049                         if (index == 0 && bitmap->sb_page) {
1050                                 /*
1051                                  * if we're here then the superblock page
1052                                  * contains some bits (PAGE_SIZE != sizeof sb)
1053                                  * we've already read it in, so just use it
1054                                  */
1055                                 page = bitmap->sb_page;
1056                                 offset = sizeof(bitmap_super_t);
1057                                 if (!file)
1058                                         page = read_sb_page(
1059                                                 bitmap->mddev,
1060                                                 bitmap->mddev->bitmap_info.offset,
1061                                                 page,
1062                                                 index, count);
1063                         } else if (file) {
1064                                 page = read_page(file, index, bitmap, count);
1065                                 offset = 0;
1066                         } else {
1067                                 page = read_sb_page(bitmap->mddev,
1068                                                     bitmap->mddev->bitmap_info.offset,
1069                                                     NULL,
1070                                                     index, count);
1071                                 offset = 0;
1072                         }
1073                         if (IS_ERR(page)) { /* read error */
1074                                 ret = PTR_ERR(page);
1075                                 goto err;
1076                         }
1077
1078                         oldindex = index;
1079                         oldpage = page;
1080
1081                         bitmap->filemap[bitmap->file_pages++] = page;
1082                         bitmap->last_page_size = count;
1083
1084                         if (outofdate) {
1085                                 /*
1086                                  * if bitmap is out of date, dirty the
1087                                  * whole page and write it out
1088                                  */
1089                                 paddr = kmap_atomic(page, KM_USER0);
1090                                 memset(paddr + offset, 0xff,
1091                                        PAGE_SIZE - offset);
1092                                 kunmap_atomic(paddr, KM_USER0);
1093                                 write_page(bitmap, page, 1);
1094
1095                                 ret = -EIO;
1096                                 if (bitmap->flags & BITMAP_WRITE_ERROR)
1097                                         goto err;
1098                         }
1099                 }
1100                 paddr = kmap_atomic(page, KM_USER0);
1101                 if (bitmap->flags & BITMAP_HOSTENDIAN)
1102                         b = test_bit(bit, paddr);
1103                 else
1104                         b = test_bit_le(bit, paddr);
1105                 kunmap_atomic(paddr, KM_USER0);
1106                 if (b) {
1107                         /* if the disk bit is set, set the memory bit */
1108                         int needed = ((sector_t)(i+1) << (CHUNK_BLOCK_SHIFT(bitmap))
1109                                       >= start);
1110                         bitmap_set_memory_bits(bitmap,
1111                                                (sector_t)i << CHUNK_BLOCK_SHIFT(bitmap),
1112                                                needed);
1113                         bit_cnt++;
1114                         set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1115                 }
1116         }
1117
1118         /* everything went OK */
1119         ret = 0;
1120         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_UNSET);
1121
1122         if (bit_cnt) { /* Kick recovery if any bits were set */
1123                 set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
1124                 md_wakeup_thread(bitmap->mddev->thread);
1125         }
1126
1127         printk(KERN_INFO "%s: bitmap initialized from disk: "
1128                "read %lu/%lu pages, set %lu of %lu bits\n",
1129                bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt, chunks);
1130
1131         return 0;
1132
1133  err:
1134         printk(KERN_INFO "%s: bitmap initialisation failed: %d\n",
1135                bmname(bitmap), ret);
1136         return ret;
1137 }
1138
1139 void bitmap_write_all(struct bitmap *bitmap)
1140 {
1141         /* We don't actually write all bitmap blocks here,
1142          * just flag them as needing to be written
1143          */
1144         int i;
1145
1146         for (i = 0; i < bitmap->file_pages; i++)
1147                 set_page_attr(bitmap, bitmap->filemap[i],
1148                               BITMAP_PAGE_NEEDWRITE);
1149 }
1150
1151 static void bitmap_count_page(struct bitmap *bitmap, sector_t offset, int inc)
1152 {
1153         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1154         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1155         bitmap->bp[page].count += inc;
1156         bitmap_checkfree(bitmap, page);
1157 }
1158 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1159                                             sector_t offset, sector_t *blocks,
1160                                             int create);
1161
1162 /*
1163  * bitmap daemon -- periodically wakes up to clean bits and flush pages
1164  *                      out to disk
1165  */
1166
1167 void bitmap_daemon_work(mddev_t *mddev)
1168 {
1169         struct bitmap *bitmap;
1170         unsigned long j;
1171         unsigned long flags;
1172         struct page *page = NULL, *lastpage = NULL;
1173         sector_t blocks;
1174         void *paddr;
1175
1176         /* Use a mutex to guard daemon_work against
1177          * bitmap_destroy.
1178          */
1179         mutex_lock(&mddev->bitmap_info.mutex);
1180         bitmap = mddev->bitmap;
1181         if (bitmap == NULL) {
1182                 mutex_unlock(&mddev->bitmap_info.mutex);
1183                 return;
1184         }
1185         if (time_before(jiffies, bitmap->daemon_lastrun
1186                         + bitmap->mddev->bitmap_info.daemon_sleep))
1187                 goto done;
1188
1189         bitmap->daemon_lastrun = jiffies;
1190         if (bitmap->allclean) {
1191                 bitmap->mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1192                 goto done;
1193         }
1194         bitmap->allclean = 1;
1195
1196         spin_lock_irqsave(&bitmap->lock, flags);
1197         for (j = 0; j < bitmap->chunks; j++) {
1198                 bitmap_counter_t *bmc;
1199                 if (!bitmap->filemap)
1200                         /* error or shutdown */
1201                         break;
1202
1203                 page = filemap_get_page(bitmap, j);
1204
1205                 if (page != lastpage) {
1206                         /* skip this page unless it's marked as needing cleaning */
1207                         if (!test_page_attr(bitmap, page, BITMAP_PAGE_CLEAN)) {
1208                                 int need_write = test_page_attr(bitmap, page,
1209                                                                 BITMAP_PAGE_NEEDWRITE);
1210                                 if (need_write)
1211                                         clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
1212
1213                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1214                                 if (need_write) {
1215                                         write_page(bitmap, page, 0);
1216                                         bitmap->allclean = 0;
1217                                 }
1218                                 spin_lock_irqsave(&bitmap->lock, flags);
1219                                 j |= (PAGE_BITS - 1);
1220                                 continue;
1221                         }
1222
1223                         /* grab the new page, sync and release the old */
1224                         if (lastpage != NULL) {
1225                                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1226                                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1227                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1228                                         write_page(bitmap, lastpage, 0);
1229                                 } else {
1230                                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1231                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1232                                 }
1233                         } else
1234                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1235                         lastpage = page;
1236
1237                         /* We are possibly going to clear some bits, so make
1238                          * sure that events_cleared is up-to-date.
1239                          */
1240                         if (bitmap->need_sync &&
1241                             bitmap->mddev->bitmap_info.external == 0) {
1242                                 bitmap_super_t *sb;
1243                                 bitmap->need_sync = 0;
1244                                 sb = kmap_atomic(bitmap->sb_page, KM_USER0);
1245                                 sb->events_cleared =
1246                                         cpu_to_le64(bitmap->events_cleared);
1247                                 kunmap_atomic(sb, KM_USER0);
1248                                 write_page(bitmap, bitmap->sb_page, 1);
1249                         }
1250                         spin_lock_irqsave(&bitmap->lock, flags);
1251                         if (!bitmap->need_sync)
1252                                 clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1253                 }
1254                 bmc = bitmap_get_counter(bitmap,
1255                                          (sector_t)j << CHUNK_BLOCK_SHIFT(bitmap),
1256                                          &blocks, 0);
1257                 if (bmc) {
1258                         if (*bmc)
1259                                 bitmap->allclean = 0;
1260
1261                         if (*bmc == 2) {
1262                                 *bmc = 1; /* maybe clear the bit next time */
1263                                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1264                         } else if (*bmc == 1 && !bitmap->need_sync) {
1265                                 /* we can clear the bit */
1266                                 *bmc = 0;
1267                                 bitmap_count_page(bitmap,
1268                                                   (sector_t)j << CHUNK_BLOCK_SHIFT(bitmap),
1269                                                   -1);
1270
1271                                 /* clear the bit */
1272                                 paddr = kmap_atomic(page, KM_USER0);
1273                                 if (bitmap->flags & BITMAP_HOSTENDIAN)
1274                                         clear_bit(file_page_offset(bitmap, j),
1275                                                   paddr);
1276                                 else
1277                                         __clear_bit_le(
1278                                                         file_page_offset(bitmap,
1279                                                                          j),
1280                                                         paddr);
1281                                 kunmap_atomic(paddr, KM_USER0);
1282                         }
1283                 } else
1284                         j |= PAGE_COUNTER_MASK;
1285         }
1286         spin_unlock_irqrestore(&bitmap->lock, flags);
1287
1288         /* now sync the final page */
1289         if (lastpage != NULL) {
1290                 spin_lock_irqsave(&bitmap->lock, flags);
1291                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1292                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1293                         spin_unlock_irqrestore(&bitmap->lock, flags);
1294                         write_page(bitmap, lastpage, 0);
1295                 } else {
1296                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1297                         spin_unlock_irqrestore(&bitmap->lock, flags);
1298                 }
1299         }
1300
1301  done:
1302         if (bitmap->allclean == 0)
1303                 bitmap->mddev->thread->timeout =
1304                         bitmap->mddev->bitmap_info.daemon_sleep;
1305         mutex_unlock(&mddev->bitmap_info.mutex);
1306 }
1307
1308 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1309                                             sector_t offset, sector_t *blocks,
1310                                             int create)
1311 __releases(bitmap->lock)
1312 __acquires(bitmap->lock)
1313 {
1314         /* If 'create', we might release the lock and reclaim it.
1315          * The lock must have been taken with interrupts enabled.
1316          * If !create, we don't release the lock.
1317          */
1318         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1319         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1320         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1321         sector_t csize;
1322         int err;
1323
1324         err = bitmap_checkpage(bitmap, page, create);
1325
1326         if (bitmap->bp[page].hijacked ||
1327             bitmap->bp[page].map == NULL)
1328                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap) +
1329                                           PAGE_COUNTER_SHIFT - 1);
1330         else
1331                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1332         *blocks = csize - (offset & (csize - 1));
1333
1334         if (err < 0)
1335                 return NULL;
1336
1337         /* now locked ... */
1338
1339         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1340                 /* should we use the first or second counter field
1341                  * of the hijacked pointer? */
1342                 int hi = (pageoff > PAGE_COUNTER_MASK);
1343                 return  &((bitmap_counter_t *)
1344                           &bitmap->bp[page].map)[hi];
1345         } else /* page is allocated */
1346                 return (bitmap_counter_t *)
1347                         &(bitmap->bp[page].map[pageoff]);
1348 }
1349
1350 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1351 {
1352         if (!bitmap)
1353                 return 0;
1354
1355         if (behind) {
1356                 int bw;
1357                 atomic_inc(&bitmap->behind_writes);
1358                 bw = atomic_read(&bitmap->behind_writes);
1359                 if (bw > bitmap->behind_writes_used)
1360                         bitmap->behind_writes_used = bw;
1361
1362                 PRINTK(KERN_DEBUG "inc write-behind count %d/%d\n",
1363                        bw, bitmap->max_write_behind);
1364         }
1365
1366         while (sectors) {
1367                 sector_t blocks;
1368                 bitmap_counter_t *bmc;
1369
1370                 spin_lock_irq(&bitmap->lock);
1371                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 1);
1372                 if (!bmc) {
1373                         spin_unlock_irq(&bitmap->lock);
1374                         return 0;
1375                 }
1376
1377                 if (unlikely(COUNTER(*bmc) == COUNTER_MAX)) {
1378                         DEFINE_WAIT(__wait);
1379                         /* note that it is safe to do the prepare_to_wait
1380                          * after the test as long as we do it before dropping
1381                          * the spinlock.
1382                          */
1383                         prepare_to_wait(&bitmap->overflow_wait, &__wait,
1384                                         TASK_UNINTERRUPTIBLE);
1385                         spin_unlock_irq(&bitmap->lock);
1386                         io_schedule();
1387                         finish_wait(&bitmap->overflow_wait, &__wait);
1388                         continue;
1389                 }
1390
1391                 switch (*bmc) {
1392                 case 0:
1393                         bitmap_file_set_bit(bitmap, offset);
1394                         bitmap_count_page(bitmap, offset, 1);
1395                         /* fall through */
1396                 case 1:
1397                         *bmc = 2;
1398                 }
1399
1400                 (*bmc)++;
1401
1402                 spin_unlock_irq(&bitmap->lock);
1403
1404                 offset += blocks;
1405                 if (sectors > blocks)
1406                         sectors -= blocks;
1407                 else
1408                         sectors = 0;
1409         }
1410         bitmap->allclean = 0;
1411         return 0;
1412 }
1413 EXPORT_SYMBOL(bitmap_startwrite);
1414
1415 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1416                      int success, int behind)
1417 {
1418         if (!bitmap)
1419                 return;
1420         if (behind) {
1421                 if (atomic_dec_and_test(&bitmap->behind_writes))
1422                         wake_up(&bitmap->behind_wait);
1423                 PRINTK(KERN_DEBUG "dec write-behind count %d/%d\n",
1424                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1425         }
1426         if (bitmap->mddev->degraded)
1427                 /* Never clear bits or update events_cleared when degraded */
1428                 success = 0;
1429
1430         while (sectors) {
1431                 sector_t blocks;
1432                 unsigned long flags;
1433                 bitmap_counter_t *bmc;
1434
1435                 spin_lock_irqsave(&bitmap->lock, flags);
1436                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 0);
1437                 if (!bmc) {
1438                         spin_unlock_irqrestore(&bitmap->lock, flags);
1439                         return;
1440                 }
1441
1442                 if (success &&
1443                     bitmap->events_cleared < bitmap->mddev->events) {
1444                         bitmap->events_cleared = bitmap->mddev->events;
1445                         bitmap->need_sync = 1;
1446                         sysfs_notify_dirent_safe(bitmap->sysfs_can_clear);
1447                 }
1448
1449                 if (!success && !NEEDED(*bmc))
1450                         *bmc |= NEEDED_MASK;
1451
1452                 if (COUNTER(*bmc) == COUNTER_MAX)
1453                         wake_up(&bitmap->overflow_wait);
1454
1455                 (*bmc)--;
1456                 if (*bmc <= 2)
1457                         set_page_attr(bitmap,
1458                                       filemap_get_page(
1459                                               bitmap,
1460                                               offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1461                                       BITMAP_PAGE_CLEAN);
1462
1463                 spin_unlock_irqrestore(&bitmap->lock, flags);
1464                 offset += blocks;
1465                 if (sectors > blocks)
1466                         sectors -= blocks;
1467                 else
1468                         sectors = 0;
1469         }
1470 }
1471 EXPORT_SYMBOL(bitmap_endwrite);
1472
1473 static int __bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1474                                int degraded)
1475 {
1476         bitmap_counter_t *bmc;
1477         int rv;
1478         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1479                 *blocks = 1024;
1480                 return 1; /* always resync if no bitmap */
1481         }
1482         spin_lock_irq(&bitmap->lock);
1483         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1484         rv = 0;
1485         if (bmc) {
1486                 /* locked */
1487                 if (RESYNC(*bmc))
1488                         rv = 1;
1489                 else if (NEEDED(*bmc)) {
1490                         rv = 1;
1491                         if (!degraded) { /* don't set/clear bits if degraded */
1492                                 *bmc |= RESYNC_MASK;
1493                                 *bmc &= ~NEEDED_MASK;
1494                         }
1495                 }
1496         }
1497         spin_unlock_irq(&bitmap->lock);
1498         bitmap->allclean = 0;
1499         return rv;
1500 }
1501
1502 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1503                       int degraded)
1504 {
1505         /* bitmap_start_sync must always report on multiples of whole
1506          * pages, otherwise resync (which is very PAGE_SIZE based) will
1507          * get confused.
1508          * So call __bitmap_start_sync repeatedly (if needed) until
1509          * At least PAGE_SIZE>>9 blocks are covered.
1510          * Return the 'or' of the result.
1511          */
1512         int rv = 0;
1513         sector_t blocks1;
1514
1515         *blocks = 0;
1516         while (*blocks < (PAGE_SIZE>>9)) {
1517                 rv |= __bitmap_start_sync(bitmap, offset,
1518                                           &blocks1, degraded);
1519                 offset += blocks1;
1520                 *blocks += blocks1;
1521         }
1522         return rv;
1523 }
1524 EXPORT_SYMBOL(bitmap_start_sync);
1525
1526 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks, int aborted)
1527 {
1528         bitmap_counter_t *bmc;
1529         unsigned long flags;
1530
1531         if (bitmap == NULL) {
1532                 *blocks = 1024;
1533                 return;
1534         }
1535         spin_lock_irqsave(&bitmap->lock, flags);
1536         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1537         if (bmc == NULL)
1538                 goto unlock;
1539         /* locked */
1540         if (RESYNC(*bmc)) {
1541                 *bmc &= ~RESYNC_MASK;
1542
1543                 if (!NEEDED(*bmc) && aborted)
1544                         *bmc |= NEEDED_MASK;
1545                 else {
1546                         if (*bmc <= 2)
1547                                 set_page_attr(bitmap,
1548                                               filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1549                                               BITMAP_PAGE_CLEAN);
1550                 }
1551         }
1552  unlock:
1553         spin_unlock_irqrestore(&bitmap->lock, flags);
1554         bitmap->allclean = 0;
1555 }
1556 EXPORT_SYMBOL(bitmap_end_sync);
1557
1558 void bitmap_close_sync(struct bitmap *bitmap)
1559 {
1560         /* Sync has finished, and any bitmap chunks that weren't synced
1561          * properly have been aborted.  It remains to us to clear the
1562          * RESYNC bit wherever it is still on
1563          */
1564         sector_t sector = 0;
1565         sector_t blocks;
1566         if (!bitmap)
1567                 return;
1568         while (sector < bitmap->mddev->resync_max_sectors) {
1569                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1570                 sector += blocks;
1571         }
1572 }
1573 EXPORT_SYMBOL(bitmap_close_sync);
1574
1575 void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector)
1576 {
1577         sector_t s = 0;
1578         sector_t blocks;
1579
1580         if (!bitmap)
1581                 return;
1582         if (sector == 0) {
1583                 bitmap->last_end_sync = jiffies;
1584                 return;
1585         }
1586         if (time_before(jiffies, (bitmap->last_end_sync
1587                                   + bitmap->mddev->bitmap_info.daemon_sleep)))
1588                 return;
1589         wait_event(bitmap->mddev->recovery_wait,
1590                    atomic_read(&bitmap->mddev->recovery_active) == 0);
1591
1592         bitmap->mddev->curr_resync_completed = sector;
1593         set_bit(MD_CHANGE_CLEAN, &bitmap->mddev->flags);
1594         sector &= ~((1ULL << CHUNK_BLOCK_SHIFT(bitmap)) - 1);
1595         s = 0;
1596         while (s < sector && s < bitmap->mddev->resync_max_sectors) {
1597                 bitmap_end_sync(bitmap, s, &blocks, 0);
1598                 s += blocks;
1599         }
1600         bitmap->last_end_sync = jiffies;
1601         sysfs_notify(&bitmap->mddev->kobj, NULL, "sync_completed");
1602 }
1603 EXPORT_SYMBOL(bitmap_cond_end_sync);
1604
1605 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1606 {
1607         /* For each chunk covered by any of these sectors, set the
1608          * counter to 1 and set resync_needed.  They should all
1609          * be 0 at this point
1610          */
1611
1612         sector_t secs;
1613         bitmap_counter_t *bmc;
1614         spin_lock_irq(&bitmap->lock);
1615         bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
1616         if (!bmc) {
1617                 spin_unlock_irq(&bitmap->lock);
1618                 return;
1619         }
1620         if (!*bmc) {
1621                 struct page *page;
1622                 *bmc = 1 | (needed ? NEEDED_MASK : 0);
1623                 bitmap_count_page(bitmap, offset, 1);
1624                 page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));
1625                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1626         }
1627         spin_unlock_irq(&bitmap->lock);
1628         bitmap->allclean = 0;
1629 }
1630
1631 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
1632 void bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1633 {
1634         unsigned long chunk;
1635
1636         for (chunk = s; chunk <= e; chunk++) {
1637                 sector_t sec = (sector_t)chunk << CHUNK_BLOCK_SHIFT(bitmap);
1638                 bitmap_set_memory_bits(bitmap, sec, 1);
1639                 bitmap_file_set_bit(bitmap, sec);
1640                 if (sec < bitmap->mddev->recovery_cp)
1641                         /* We are asserting that the array is dirty,
1642                          * so move the recovery_cp address back so
1643                          * that it is obvious that it is dirty
1644                          */
1645                         bitmap->mddev->recovery_cp = sec;
1646         }
1647 }
1648
1649 /*
1650  * flush out any pending updates
1651  */
1652 void bitmap_flush(mddev_t *mddev)
1653 {
1654         struct bitmap *bitmap = mddev->bitmap;
1655         long sleep;
1656
1657         if (!bitmap) /* there was no bitmap */
1658                 return;
1659
1660         /* run the daemon_work three time to ensure everything is flushed
1661          * that can be
1662          */
1663         sleep = mddev->bitmap_info.daemon_sleep * 2;
1664         bitmap->daemon_lastrun -= sleep;
1665         bitmap_daemon_work(mddev);
1666         bitmap->daemon_lastrun -= sleep;
1667         bitmap_daemon_work(mddev);
1668         bitmap->daemon_lastrun -= sleep;
1669         bitmap_daemon_work(mddev);
1670         bitmap_update_sb(bitmap);
1671 }
1672
1673 /*
1674  * free memory that was allocated
1675  */
1676 static void bitmap_free(struct bitmap *bitmap)
1677 {
1678         unsigned long k, pages;
1679         struct bitmap_page *bp;
1680
1681         if (!bitmap) /* there was no bitmap */
1682                 return;
1683
1684         /* release the bitmap file and kill the daemon */
1685         bitmap_file_put(bitmap);
1686
1687         bp = bitmap->bp;
1688         pages = bitmap->pages;
1689
1690         /* free all allocated memory */
1691
1692         if (bp) /* deallocate the page memory */
1693                 for (k = 0; k < pages; k++)
1694                         if (bp[k].map && !bp[k].hijacked)
1695                                 kfree(bp[k].map);
1696         kfree(bp);
1697         kfree(bitmap);
1698 }
1699
1700 void bitmap_destroy(mddev_t *mddev)
1701 {
1702         struct bitmap *bitmap = mddev->bitmap;
1703
1704         if (!bitmap) /* there was no bitmap */
1705                 return;
1706
1707         mutex_lock(&mddev->bitmap_info.mutex);
1708         mddev->bitmap = NULL; /* disconnect from the md device */
1709         mutex_unlock(&mddev->bitmap_info.mutex);
1710         if (mddev->thread)
1711                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1712
1713         if (bitmap->sysfs_can_clear)
1714                 sysfs_put(bitmap->sysfs_can_clear);
1715
1716         bitmap_free(bitmap);
1717 }
1718
1719 /*
1720  * initialize the bitmap structure
1721  * if this returns an error, bitmap_destroy must be called to do clean up
1722  */
1723 int bitmap_create(mddev_t *mddev)
1724 {
1725         struct bitmap *bitmap;
1726         sector_t blocks = mddev->resync_max_sectors;
1727         unsigned long chunks;
1728         unsigned long pages;
1729         struct file *file = mddev->bitmap_info.file;
1730         int err;
1731         struct sysfs_dirent *bm = NULL;
1732
1733         BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
1734
1735         if (!file
1736             && !mddev->bitmap_info.offset) /* bitmap disabled, nothing to do */
1737                 return 0;
1738
1739         BUG_ON(file && mddev->bitmap_info.offset);
1740
1741         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1742         if (!bitmap)
1743                 return -ENOMEM;
1744
1745         spin_lock_init(&bitmap->lock);
1746         atomic_set(&bitmap->pending_writes, 0);
1747         init_waitqueue_head(&bitmap->write_wait);
1748         init_waitqueue_head(&bitmap->overflow_wait);
1749         init_waitqueue_head(&bitmap->behind_wait);
1750
1751         bitmap->mddev = mddev;
1752
1753         if (mddev->kobj.sd)
1754                 bm = sysfs_get_dirent(mddev->kobj.sd, NULL, "bitmap");
1755         if (bm) {
1756                 bitmap->sysfs_can_clear = sysfs_get_dirent(bm, NULL, "can_clear");
1757                 sysfs_put(bm);
1758         } else
1759                 bitmap->sysfs_can_clear = NULL;
1760
1761         bitmap->file = file;
1762         if (file) {
1763                 get_file(file);
1764                 /* As future accesses to this file will use bmap,
1765                  * and bypass the page cache, we must sync the file
1766                  * first.
1767                  */
1768                 vfs_fsync(file, 1);
1769         }
1770         /* read superblock from bitmap file (this sets mddev->bitmap_info.chunksize) */
1771         if (!mddev->bitmap_info.external) {
1772                 /*
1773                  * If 'MD_ARRAY_FIRST_USE' is set, then device-mapper is
1774                  * instructing us to create a new on-disk bitmap instance.
1775                  */
1776                 if (test_and_clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags))
1777                         err = bitmap_new_disk_sb(bitmap);
1778                 else
1779                         err = bitmap_read_sb(bitmap);
1780         } else {
1781                 err = 0;
1782                 if (mddev->bitmap_info.chunksize == 0 ||
1783                     mddev->bitmap_info.daemon_sleep == 0)
1784                         /* chunksize and time_base need to be
1785                          * set first. */
1786                         err = -EINVAL;
1787         }
1788         if (err)
1789                 goto error;
1790
1791         bitmap->daemon_lastrun = jiffies;
1792         bitmap->chunkshift = ffz(~mddev->bitmap_info.chunksize);
1793
1794         /* now that chunksize and chunkshift are set, we can use these macros */
1795         chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) >>
1796                         CHUNK_BLOCK_SHIFT(bitmap);
1797         pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
1798
1799         BUG_ON(!pages);
1800
1801         bitmap->chunks = chunks;
1802         bitmap->pages = pages;
1803         bitmap->missing_pages = pages;
1804
1805 #ifdef INJECT_FATAL_FAULT_1
1806         bitmap->bp = NULL;
1807 #else
1808         bitmap->bp = kzalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
1809 #endif
1810         err = -ENOMEM;
1811         if (!bitmap->bp)
1812                 goto error;
1813
1814         printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
1815                 pages, bmname(bitmap));
1816
1817         mddev->bitmap = bitmap;
1818
1819
1820         return (bitmap->flags & BITMAP_WRITE_ERROR) ? -EIO : 0;
1821
1822  error:
1823         bitmap_free(bitmap);
1824         return err;
1825 }
1826
1827 int bitmap_load(mddev_t *mddev)
1828 {
1829         int err = 0;
1830         sector_t start = 0;
1831         sector_t sector = 0;
1832         struct bitmap *bitmap = mddev->bitmap;
1833
1834         if (!bitmap)
1835                 goto out;
1836
1837         /* Clear out old bitmap info first:  Either there is none, or we
1838          * are resuming after someone else has possibly changed things,
1839          * so we should forget old cached info.
1840          * All chunks should be clean, but some might need_sync.
1841          */
1842         while (sector < mddev->resync_max_sectors) {
1843                 sector_t blocks;
1844                 bitmap_start_sync(bitmap, sector, &blocks, 0);
1845                 sector += blocks;
1846         }
1847         bitmap_close_sync(bitmap);
1848
1849         if (mddev->degraded == 0
1850             || bitmap->events_cleared == mddev->events)
1851                 /* no need to keep dirty bits to optimise a
1852                  * re-add of a missing device */
1853                 start = mddev->recovery_cp;
1854
1855         err = bitmap_init_from_disk(bitmap, start);
1856
1857         if (err)
1858                 goto out;
1859
1860         mddev->thread->timeout = mddev->bitmap_info.daemon_sleep;
1861         md_wakeup_thread(mddev->thread);
1862
1863         bitmap_update_sb(bitmap);
1864
1865         if (bitmap->flags & BITMAP_WRITE_ERROR)
1866                 err = -EIO;
1867 out:
1868         return err;
1869 }
1870 EXPORT_SYMBOL_GPL(bitmap_load);
1871
1872 static ssize_t
1873 location_show(mddev_t *mddev, char *page)
1874 {
1875         ssize_t len;
1876         if (mddev->bitmap_info.file)
1877                 len = sprintf(page, "file");
1878         else if (mddev->bitmap_info.offset)
1879                 len = sprintf(page, "%+lld", (long long)mddev->bitmap_info.offset);
1880         else
1881                 len = sprintf(page, "none");
1882         len += sprintf(page+len, "\n");
1883         return len;
1884 }
1885
1886 static ssize_t
1887 location_store(mddev_t *mddev, const char *buf, size_t len)
1888 {
1889
1890         if (mddev->pers) {
1891                 if (!mddev->pers->quiesce)
1892                         return -EBUSY;
1893                 if (mddev->recovery || mddev->sync_thread)
1894                         return -EBUSY;
1895         }
1896
1897         if (mddev->bitmap || mddev->bitmap_info.file ||
1898             mddev->bitmap_info.offset) {
1899                 /* bitmap already configured.  Only option is to clear it */
1900                 if (strncmp(buf, "none", 4) != 0)
1901                         return -EBUSY;
1902                 if (mddev->pers) {
1903                         mddev->pers->quiesce(mddev, 1);
1904                         bitmap_destroy(mddev);
1905                         mddev->pers->quiesce(mddev, 0);
1906                 }
1907                 mddev->bitmap_info.offset = 0;
1908                 if (mddev->bitmap_info.file) {
1909                         struct file *f = mddev->bitmap_info.file;
1910                         mddev->bitmap_info.file = NULL;
1911                         restore_bitmap_write_access(f);
1912                         fput(f);
1913                 }
1914         } else {
1915                 /* No bitmap, OK to set a location */
1916                 long long offset;
1917                 if (strncmp(buf, "none", 4) == 0)
1918                         /* nothing to be done */;
1919                 else if (strncmp(buf, "file:", 5) == 0) {
1920                         /* Not supported yet */
1921                         return -EINVAL;
1922                 } else {
1923                         int rv;
1924                         if (buf[0] == '+')
1925                                 rv = strict_strtoll(buf+1, 10, &offset);
1926                         else
1927                                 rv = strict_strtoll(buf, 10, &offset);
1928                         if (rv)
1929                                 return rv;
1930                         if (offset == 0)
1931                                 return -EINVAL;
1932                         if (mddev->bitmap_info.external == 0 &&
1933                             mddev->major_version == 0 &&
1934                             offset != mddev->bitmap_info.default_offset)
1935                                 return -EINVAL;
1936                         mddev->bitmap_info.offset = offset;
1937                         if (mddev->pers) {
1938                                 mddev->pers->quiesce(mddev, 1);
1939                                 rv = bitmap_create(mddev);
1940                                 if (rv) {
1941                                         bitmap_destroy(mddev);
1942                                         mddev->bitmap_info.offset = 0;
1943                                 }
1944                                 mddev->pers->quiesce(mddev, 0);
1945                                 if (rv)
1946                                         return rv;
1947                         }
1948                 }
1949         }
1950         if (!mddev->external) {
1951                 /* Ensure new bitmap info is stored in
1952                  * metadata promptly.
1953                  */
1954                 set_bit(MD_CHANGE_DEVS, &mddev->flags);
1955                 md_wakeup_thread(mddev->thread);
1956         }
1957         return len;
1958 }
1959
1960 static struct md_sysfs_entry bitmap_location =
1961 __ATTR(location, S_IRUGO|S_IWUSR, location_show, location_store);
1962
1963 static ssize_t
1964 timeout_show(mddev_t *mddev, char *page)
1965 {
1966         ssize_t len;
1967         unsigned long secs = mddev->bitmap_info.daemon_sleep / HZ;
1968         unsigned long jifs = mddev->bitmap_info.daemon_sleep % HZ;
1969
1970         len = sprintf(page, "%lu", secs);
1971         if (jifs)
1972                 len += sprintf(page+len, ".%03u", jiffies_to_msecs(jifs));
1973         len += sprintf(page+len, "\n");
1974         return len;
1975 }
1976
1977 static ssize_t
1978 timeout_store(mddev_t *mddev, const char *buf, size_t len)
1979 {
1980         /* timeout can be set at any time */
1981         unsigned long timeout;
1982         int rv = strict_strtoul_scaled(buf, &timeout, 4);
1983         if (rv)
1984                 return rv;
1985
1986         /* just to make sure we don't overflow... */
1987         if (timeout >= LONG_MAX / HZ)
1988                 return -EINVAL;
1989
1990         timeout = timeout * HZ / 10000;
1991
1992         if (timeout >= MAX_SCHEDULE_TIMEOUT)
1993                 timeout = MAX_SCHEDULE_TIMEOUT-1;
1994         if (timeout < 1)
1995                 timeout = 1;
1996         mddev->bitmap_info.daemon_sleep = timeout;
1997         if (mddev->thread) {
1998                 /* if thread->timeout is MAX_SCHEDULE_TIMEOUT, then
1999                  * the bitmap is all clean and we don't need to
2000                  * adjust the timeout right now
2001                  */
2002                 if (mddev->thread->timeout < MAX_SCHEDULE_TIMEOUT) {
2003                         mddev->thread->timeout = timeout;
2004                         md_wakeup_thread(mddev->thread);
2005                 }
2006         }
2007         return len;
2008 }
2009
2010 static struct md_sysfs_entry bitmap_timeout =
2011 __ATTR(time_base, S_IRUGO|S_IWUSR, timeout_show, timeout_store);
2012
2013 static ssize_t
2014 backlog_show(mddev_t *mddev, char *page)
2015 {
2016         return sprintf(page, "%lu\n", mddev->bitmap_info.max_write_behind);
2017 }
2018
2019 static ssize_t
2020 backlog_store(mddev_t *mddev, const char *buf, size_t len)
2021 {
2022         unsigned long backlog;
2023         int rv = strict_strtoul(buf, 10, &backlog);
2024         if (rv)
2025                 return rv;
2026         if (backlog > COUNTER_MAX)
2027                 return -EINVAL;
2028         mddev->bitmap_info.max_write_behind = backlog;
2029         return len;
2030 }
2031
2032 static struct md_sysfs_entry bitmap_backlog =
2033 __ATTR(backlog, S_IRUGO|S_IWUSR, backlog_show, backlog_store);
2034
2035 static ssize_t
2036 chunksize_show(mddev_t *mddev, char *page)
2037 {
2038         return sprintf(page, "%lu\n", mddev->bitmap_info.chunksize);
2039 }
2040
2041 static ssize_t
2042 chunksize_store(mddev_t *mddev, const char *buf, size_t len)
2043 {
2044         /* Can only be changed when no bitmap is active */
2045         int rv;
2046         unsigned long csize;
2047         if (mddev->bitmap)
2048                 return -EBUSY;
2049         rv = strict_strtoul(buf, 10, &csize);
2050         if (rv)
2051                 return rv;
2052         if (csize < 512 ||
2053             !is_power_of_2(csize))
2054                 return -EINVAL;
2055         mddev->bitmap_info.chunksize = csize;
2056         return len;
2057 }
2058
2059 static struct md_sysfs_entry bitmap_chunksize =
2060 __ATTR(chunksize, S_IRUGO|S_IWUSR, chunksize_show, chunksize_store);
2061
2062 static ssize_t metadata_show(mddev_t *mddev, char *page)
2063 {
2064         return sprintf(page, "%s\n", (mddev->bitmap_info.external
2065                                       ? "external" : "internal"));
2066 }
2067
2068 static ssize_t metadata_store(mddev_t *mddev, const char *buf, size_t len)
2069 {
2070         if (mddev->bitmap ||
2071             mddev->bitmap_info.file ||
2072             mddev->bitmap_info.offset)
2073                 return -EBUSY;
2074         if (strncmp(buf, "external", 8) == 0)
2075                 mddev->bitmap_info.external = 1;
2076         else if (strncmp(buf, "internal", 8) == 0)
2077                 mddev->bitmap_info.external = 0;
2078         else
2079                 return -EINVAL;
2080         return len;
2081 }
2082
2083 static struct md_sysfs_entry bitmap_metadata =
2084 __ATTR(metadata, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
2085
2086 static ssize_t can_clear_show(mddev_t *mddev, char *page)
2087 {
2088         int len;
2089         if (mddev->bitmap)
2090                 len = sprintf(page, "%s\n", (mddev->bitmap->need_sync ?
2091                                              "false" : "true"));
2092         else
2093                 len = sprintf(page, "\n");
2094         return len;
2095 }
2096
2097 static ssize_t can_clear_store(mddev_t *mddev, const char *buf, size_t len)
2098 {
2099         if (mddev->bitmap == NULL)
2100                 return -ENOENT;
2101         if (strncmp(buf, "false", 5) == 0)
2102                 mddev->bitmap->need_sync = 1;
2103         else if (strncmp(buf, "true", 4) == 0) {
2104                 if (mddev->degraded)
2105                         return -EBUSY;
2106                 mddev->bitmap->need_sync = 0;
2107         } else
2108                 return -EINVAL;
2109         return len;
2110 }
2111
2112 static struct md_sysfs_entry bitmap_can_clear =
2113 __ATTR(can_clear, S_IRUGO|S_IWUSR, can_clear_show, can_clear_store);
2114
2115 static ssize_t
2116 behind_writes_used_show(mddev_t *mddev, char *page)
2117 {
2118         if (mddev->bitmap == NULL)
2119                 return sprintf(page, "0\n");
2120         return sprintf(page, "%lu\n",
2121                        mddev->bitmap->behind_writes_used);
2122 }
2123
2124 static ssize_t
2125 behind_writes_used_reset(mddev_t *mddev, const char *buf, size_t len)
2126 {
2127         if (mddev->bitmap)
2128                 mddev->bitmap->behind_writes_used = 0;
2129         return len;
2130 }
2131
2132 static struct md_sysfs_entry max_backlog_used =
2133 __ATTR(max_backlog_used, S_IRUGO | S_IWUSR,
2134        behind_writes_used_show, behind_writes_used_reset);
2135
2136 static struct attribute *md_bitmap_attrs[] = {
2137         &bitmap_location.attr,
2138         &bitmap_timeout.attr,
2139         &bitmap_backlog.attr,
2140         &bitmap_chunksize.attr,
2141         &bitmap_metadata.attr,
2142         &bitmap_can_clear.attr,
2143         &max_backlog_used.attr,
2144         NULL
2145 };
2146 struct attribute_group md_bitmap_group = {
2147         .name = "bitmap",
2148         .attrs = md_bitmap_attrs,
2149 };
2150