SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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  * - added bitmap daemon (to asynchronously clear bitmap bits from disk)
  11  */
  12
  13 /*
  14  * Still to do:
  15  *
  16  * flush after percent set rather than just time based. (maybe both).
  17  * wait if count gets too high, wake when it drops to half.
  18  * allow bitmap to be mirrored with superblock (before or after...)
  19  * allow hot-add to re-instate a current device.
  20  * allow hot-add of bitmap after quiessing device
  21  */
  22
  23 #include <linux/module.h>
  24 #include <linux/version.h>
  25 #include <linux/errno.h>
  26 #include <linux/slab.h>
  27 #include <linux/init.h>
  28 #include <linux/config.h>
  29 #include <linux/timer.h>
  30 #include <linux/sched.h>
  31 #include <linux/list.h>
  32 #include <linux/file.h>
  33 #include <linux/mount.h>
  34 #include <linux/buffer_head.h>
  35 #include <linux/raid/md.h>
  36 #include <linux/raid/bitmap.h>
  37
  38 /* debug macros */
  39
  40 #define DEBUG 0
  41
  42 #if DEBUG
  43 /* these are for debugging purposes only! */
  44
  45 /* define one and only one of these */
  46 #define INJECT_FAULTS_1 0 /* cause bitmap_alloc_page to fail always */
  47 #define INJECT_FAULTS_2 0 /* cause bitmap file to be kicked when first bit set*/
  48 #define INJECT_FAULTS_3 0 /* treat bitmap file as kicked at init time */
  49 #define INJECT_FAULTS_4 0 /* undef */
  50 #define INJECT_FAULTS_5 0 /* undef */
  51 #define INJECT_FAULTS_6 0
  52
  53 /* if these are defined, the driver will fail! debug only */
  54 #define INJECT_FATAL_FAULT_1 0 /* fail kmalloc, causing bitmap_create to fail */
  55 #define INJECT_FATAL_FAULT_2 0 /* undef */
  56 #define INJECT_FATAL_FAULT_3 0 /* undef */
  57 #endif
  58
  59 //#define DPRINTK PRINTK /* set this NULL to avoid verbose debug output */
  60 #define DPRINTK(x...) do { } while(0)
  61
  62 #ifndef PRINTK
  63 #  if DEBUG > 0
  64 #    define PRINTK(x...) printk(KERN_DEBUG x)
  65 #  else
  66 #    define PRINTK(x...)
  67 #  endif
  68 #endif
  69
  70 static inline char * bmname(struct bitmap *bitmap)
  71 {
  72         return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
  73 }
  74
  75
  76 /*
  77  * test if the bitmap is active
  78  */
  79 int bitmap_active(struct bitmap *bitmap)
  80 {
  81         unsigned long flags;
  82         int res = 0;
  83
  84         if (!bitmap)
  85                 return res;
  86         spin_lock_irqsave(&bitmap->lock, flags);
  87         res = bitmap->flags & BITMAP_ACTIVE;
  88         spin_unlock_irqrestore(&bitmap->lock, flags);
  89         return res;
  90 }
  91
  92 #define WRITE_POOL_SIZE 256
  93 /* mempool for queueing pending writes on the bitmap file */
  94 static void *write_pool_alloc(unsigned int gfp_flags, void *data)
  95 {
  96         return kmalloc(sizeof(struct page_list), gfp_flags);
  97 }
  98
  99 static void write_pool_free(void *ptr, void *data)
 100 {
 101         kfree(ptr);
 102 }
 103
 104 /*
 105  * just a placeholder - calls kmalloc for bitmap pages
 106  */
 107 static unsigned char *bitmap_alloc_page(struct bitmap *bitmap)
 108 {
 109         unsigned char *page;
 110
 111 #if INJECT_FAULTS_1
 112         page = NULL;
 113 #else
 114         page = kmalloc(PAGE_SIZE, GFP_NOIO);
 115 #endif
 116         if (!page)
 117                 printk("%s: bitmap_alloc_page FAILED\n", bmname(bitmap));
 118         else
 119                 PRINTK("%s: bitmap_alloc_page: allocated page at %p\n",
 120                         bmname(bitmap), page);
 121         return page;
 122 }
 123
 124 /*
 125  * for now just a placeholder -- just calls kfree for bitmap pages
 126  */
 127 static void bitmap_free_page(struct bitmap *bitmap, unsigned char *page)
 128 {
 129         PRINTK("%s: bitmap_free_page: free page %p\n", bmname(bitmap), page);
 130         kfree(page);
 131 }
 132
 133 /*
 134  * check a page and, if necessary, allocate it (or hijack it if the alloc fails)
 135  *
 136  * 1) check to see if this page is allocated, if it's not then try to alloc
 137  * 2) if the alloc fails, set the page's hijacked flag so we'll use the
 138  *    page pointer directly as a counter
 139  *
 140  * if we find our page, we increment the page's refcount so that it stays
 141  * allocated while we're using it
 142  */
 143 static int bitmap_checkpage(struct bitmap *bitmap, unsigned long page, int create)
 144 {
 145         unsigned char *mappage;
 146
 147         if (page >= bitmap->pages) {
 148                 printk(KERN_ALERT
 149                         "%s: invalid bitmap page request: %lu (> %lu)\n",
 150                         bmname(bitmap), page, bitmap->pages-1);
 151                 return -EINVAL;
 152         }
 153
 154
 155         if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
 156                 return 0;
 157
 158         if (bitmap->bp[page].map) /* page is already allocated, just return */
 159                 return 0;
 160
 161         if (!create)
 162                 return -ENOENT;
 163
 164         spin_unlock_irq(&bitmap->lock);
 165
 166         /* this page has not been allocated yet */
 167
 168         if ((mappage = bitmap_alloc_page(bitmap)) == NULL) {
 169                 PRINTK("%s: bitmap map page allocation failed, hijacking\n",
 170                         bmname(bitmap));
 171                 /* failed - set the hijacked flag so that we can use the
 172                  * pointer as a counter */
 173                 spin_lock_irq(&bitmap->lock);
 174                 if (!bitmap->bp[page].map)
 175                         bitmap->bp[page].hijacked = 1;
 176                 goto out;
 177         }
 178
 179         /* got a page */
 180
 181         spin_lock_irq(&bitmap->lock);
 182
 183         /* recheck the page */
 184
 185         if (bitmap->bp[page].map || bitmap->bp[page].hijacked) {
 186                 /* somebody beat us to getting the page */
 187                 bitmap_free_page(bitmap, mappage);
 188                 return 0;
 189         }
 190
 191         /* no page was in place and we have one, so install it */
 192
 193         memset(mappage, 0, PAGE_SIZE);
 194         bitmap->bp[page].map = mappage;
 195         bitmap->missing_pages--;
 196 out:
 197         return 0;
 198 }
 199
 200
 201 /* if page is completely empty, put it back on the free list, or dealloc it */
 202 /* if page was hijacked, unmark the flag so it might get alloced next time */
 203 /* Note: lock should be held when calling this */
 204 static inline void bitmap_checkfree(struct bitmap *bitmap, unsigned long page)
 205 {
 206         char *ptr;
 207
 208         if (bitmap->bp[page].count) /* page is still busy */
 209                 return;
 210
 211         /* page is no longer in use, it can be released */
 212
 213         if (bitmap->bp[page].hijacked) { /* page was hijacked, undo this now */
 214                 bitmap->bp[page].hijacked = 0;
 215                 bitmap->bp[page].map = NULL;
 216                 return;
 217         }
 218
 219         /* normal case, free the page */
 220
 221 #if 0
 222 /* actually ... let's not.  We will probably need the page again exactly when
 223  * memory is tight and we are flusing to disk
 224  */
 225         return;
 226 #else
 227         ptr = bitmap->bp[page].map;
 228         bitmap->bp[page].map = NULL;
 229         bitmap->missing_pages++;
 230         bitmap_free_page(bitmap, ptr);
 231         return;
 232 #endif
 233 }
 234
 235
 236 /*
 237  * bitmap file handling - read and write the bitmap file and its superblock
 238  */
 239
 240 /* copy the pathname of a file to a buffer */
 241 char *file_path(struct file *file, char *buf, int count)
 242 {
 243         struct dentry *d;
 244         struct vfsmount *v;
 245
 246         if (!buf)
 247                 return NULL;
 248
 249         d = file->f_dentry;
 250         v = file->f_vfsmnt;
 251
 252         buf = d_path(d, v, buf, count);
 253
 254         return IS_ERR(buf) ? NULL : buf;
 255 }
 256
 257 /*
 258  * basic page I/O operations
 259  */
 260
 261 /* IO operations when bitmap is stored near all superblocks */
 262 static struct page *read_sb_page(mddev_t *mddev, long offset, unsigned long index)
 263 {
 264         /* choose a good rdev and read the page from there */
 265
 266         mdk_rdev_t *rdev;
 267         struct list_head *tmp;
 268         struct page *page = alloc_page(GFP_KERNEL);
 269         sector_t target;
 270
 271         if (!page)
 272                 return ERR_PTR(-ENOMEM);
 273         do {
 274                 ITERATE_RDEV(mddev, rdev, tmp)
 275                         if (rdev->in_sync && !rdev->faulty)
 276                                 goto found;
 277                 return ERR_PTR(-EIO);
 278
 279         found:
 280                 target = (rdev->sb_offset << 1) + offset + index * (PAGE_SIZE/512);
 281
 282         } while (!sync_page_io(rdev->bdev, target, PAGE_SIZE, page, READ));
 283
 284         page->index = index;
 285         return page;
 286 }
 287
 288 static int write_sb_page(mddev_t *mddev, long offset, struct page *page, int wait)
 289 {
 290         mdk_rdev_t *rdev;
 291         struct list_head *tmp;
 292
 293         ITERATE_RDEV(mddev, rdev, tmp)
 294                 if (rdev->in_sync && !rdev->faulty)
 295                         md_super_write(mddev, rdev,
 296                                        (rdev->sb_offset<<1) + offset
 297                                        + page->index * (PAGE_SIZE/512),
 298                                        PAGE_SIZE,
 299                                        page);
 300
 301         if (wait)
 302                 wait_event(mddev->sb_wait, atomic_read(&mddev->pending_writes)==0);
 303         return 0;
 304 }
 305
 306 /*
 307  * write out a page to a file
 308  */
 309 static int write_page(struct bitmap *bitmap, struct page *page, int wait)
 310 {
 311         int ret = -ENOMEM;
 312
 313         if (bitmap->file == NULL)
 314                 return write_sb_page(bitmap->mddev, bitmap->offset, page, wait);
 315
 316         lock_page(page);
 317
 318         ret = page->mapping->a_ops->prepare_write(NULL, page, 0, PAGE_SIZE);
 319         if (!ret)
 320                 ret = page->mapping->a_ops->commit_write(NULL, page, 0,
 321                         PAGE_SIZE);
 322         if (ret) {
 323                 unlock_page(page);
 324                 return ret;
 325         }
 326
 327         set_page_dirty(page); /* force it to be written out */
 328
 329         if (!wait) {
 330                 /* add to list to be waited for by daemon */
 331                 struct page_list *item = mempool_alloc(bitmap->write_pool, GFP_NOIO);
 332                 item->page = page;
 333                 page_cache_get(page);
 334                 spin_lock(&bitmap->write_lock);
 335                 list_add(&item->list, &bitmap->complete_pages);
 336                 spin_unlock(&bitmap->write_lock);
 337                 md_wakeup_thread(bitmap->writeback_daemon);
 338         }
 339         return write_one_page(page, wait);
 340 }
 341
 342 /* read a page from a file, pinning it into cache, and return bytes_read */
 343 static struct page *read_page(struct file *file, unsigned long index,
 344                                         unsigned long *bytes_read)
 345 {
 346         struct inode *inode = file->f_mapping->host;
 347         struct page *page = NULL;
 348         loff_t isize = i_size_read(inode);
 349         unsigned long end_index = isize >> PAGE_CACHE_SHIFT;
 350
 351         PRINTK("read bitmap file (%dB @ %Lu)\n", (int)PAGE_CACHE_SIZE,
 352                         (unsigned long long)index << PAGE_CACHE_SHIFT);
 353
 354         page = read_cache_page(inode->i_mapping, index,
 355                         (filler_t *)inode->i_mapping->a_ops->readpage, file);
 356         if (IS_ERR(page))
 357                 goto out;
 358         wait_on_page_locked(page);
 359         if (!PageUptodate(page) || PageError(page)) {
 360                 page_cache_release(page);
 361                 page = ERR_PTR(-EIO);
 362                 goto out;
 363         }
 364
 365         if (index > end_index) /* we have read beyond EOF */
 366                 *bytes_read = 0;
 367         else if (index == end_index) /* possible short read */
 368                 *bytes_read = isize & ~PAGE_CACHE_MASK;
 369         else
 370                 *bytes_read = PAGE_CACHE_SIZE; /* got a full page */
 371 out:
 372         if (IS_ERR(page))
 373                 printk(KERN_ALERT "md: bitmap read error: (%dB @ %Lu): %ld\n",
 374                         (int)PAGE_CACHE_SIZE,
 375                         (unsigned long long)index << PAGE_CACHE_SHIFT,
 376                         PTR_ERR(page));
 377         return page;
 378 }
 379
 380 /*
 381  * bitmap file superblock operations
 382  */
 383
 384 /* update the event counter and sync the superblock to disk */
 385 int bitmap_update_sb(struct bitmap *bitmap)
 386 {
 387         bitmap_super_t *sb;
 388         unsigned long flags;
 389
 390         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
 391                 return 0;
 392         spin_lock_irqsave(&bitmap->lock, flags);
 393         if (!bitmap->sb_page) { /* no superblock */
 394                 spin_unlock_irqrestore(&bitmap->lock, flags);
 395                 return 0;
 396         }
 397         spin_unlock_irqrestore(&bitmap->lock, flags);
 398         sb = (bitmap_super_t *)kmap(bitmap->sb_page);
 399         sb->events = cpu_to_le64(bitmap->mddev->events);
 400         if (!bitmap->mddev->degraded)
 401                 sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
 402         kunmap(bitmap->sb_page);
 403         return write_page(bitmap, bitmap->sb_page, 0);
 404 }
 405
 406 /* print out the bitmap file superblock */
 407 void bitmap_print_sb(struct bitmap *bitmap)
 408 {
 409         bitmap_super_t *sb;
 410
 411         if (!bitmap || !bitmap->sb_page)
 412                 return;
 413         sb = (bitmap_super_t *)kmap(bitmap->sb_page);
 414         printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
 415         printk(KERN_DEBUG "         magic: %08x\n", le32_to_cpu(sb->magic));
 416         printk(KERN_DEBUG "       version: %d\n", le32_to_cpu(sb->version));
 417         printk(KERN_DEBUG "          uuid: %08x.%08x.%08x.%08x\n",
 418                                         *(__u32 *)(sb->uuid+0),
 419                                         *(__u32 *)(sb->uuid+4),
 420                                         *(__u32 *)(sb->uuid+8),
 421                                         *(__u32 *)(sb->uuid+12));
 422         printk(KERN_DEBUG "        events: %llu\n",
 423                         (unsigned long long) le64_to_cpu(sb->events));
 424         printk(KERN_DEBUG "events cleared: %llu\n",
 425                         (unsigned long long) le64_to_cpu(sb->events_cleared));
 426         printk(KERN_DEBUG "         state: %08x\n", le32_to_cpu(sb->state));
 427         printk(KERN_DEBUG "     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
 428         printk(KERN_DEBUG "  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
 429         printk(KERN_DEBUG "     sync size: %llu KB\n",
 430                         (unsigned long long)le64_to_cpu(sb->sync_size)/2);
 431         kunmap(bitmap->sb_page);
 432 }
 433
 434 /* read the superblock from the bitmap file and initialize some bitmap fields */
 435 static int bitmap_read_sb(struct bitmap *bitmap)
 436 {
 437         char *reason = NULL;
 438         bitmap_super_t *sb;
 439         unsigned long chunksize, daemon_sleep;
 440         unsigned long bytes_read;
 441         unsigned long long events;
 442         int err = -EINVAL;
 443
 444         /* page 0 is the superblock, read it... */
 445         if (bitmap->file)
 446                 bitmap->sb_page = read_page(bitmap->file, 0, &bytes_read);
 447         else {
 448                 bitmap->sb_page = read_sb_page(bitmap->mddev, bitmap->offset, 0);
 449                 bytes_read = PAGE_SIZE;
 450         }
 451         if (IS_ERR(bitmap->sb_page)) {
 452                 err = PTR_ERR(bitmap->sb_page);
 453                 bitmap->sb_page = NULL;
 454                 return err;
 455         }
 456
 457         sb = (bitmap_super_t *)kmap(bitmap->sb_page);
 458
 459         if (bytes_read < sizeof(*sb)) { /* short read */
 460                 printk(KERN_INFO "%s: bitmap file superblock truncated\n",
 461                         bmname(bitmap));
 462                 err = -ENOSPC;
 463                 goto out;
 464         }
 465
 466         chunksize = le32_to_cpu(sb->chunksize);
 467         daemon_sleep = le32_to_cpu(sb->daemon_sleep);
 468
 469         /* verify that the bitmap-specific fields are valid */
 470         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
 471                 reason = "bad magic";
 472         else if (sb->version != cpu_to_le32(BITMAP_MAJOR))
 473                 reason = "unrecognized superblock version";
 474         else if (chunksize < 512 || chunksize > (1024 * 1024 * 4))
 475                 reason = "bitmap chunksize out of range (512B - 4MB)";
 476         else if ((1 << ffz(~chunksize)) != chunksize)
 477                 reason = "bitmap chunksize not a power of 2";
 478         else if (daemon_sleep < 1 || daemon_sleep > 15)
 479                 reason = "daemon sleep period out of range";
 480         if (reason) {
 481                 printk(KERN_INFO "%s: invalid bitmap file superblock: %s\n",
 482                         bmname(bitmap), reason);
 483                 goto out;
 484         }
 485
 486         /* keep the array size field of the bitmap superblock up to date */
 487         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 488
 489         if (!bitmap->mddev->persistent)
 490                 goto success;
 491
 492         /*
 493          * if we have a persistent array superblock, compare the
 494          * bitmap's UUID and event counter to the mddev's
 495          */
 496         if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
 497                 printk(KERN_INFO "%s: bitmap superblock UUID mismatch\n",
 498                         bmname(bitmap));
 499                 goto out;
 500         }
 501         events = le64_to_cpu(sb->events);
 502         if (events < bitmap->mddev->events) {
 503                 printk(KERN_INFO "%s: bitmap file is out of date (%llu < %llu) "
 504                         "-- forcing full recovery\n", bmname(bitmap), events,
 505                         (unsigned long long) bitmap->mddev->events);
 506                 sb->state |= BITMAP_STALE;
 507         }
 508 success:
 509         /* assign fields using values from superblock */
 510         bitmap->chunksize = chunksize;
 511         bitmap->daemon_sleep = daemon_sleep;
 512         bitmap->flags |= sb->state;
 513         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
 514         err = 0;
 515 out:
 516         kunmap(bitmap->sb_page);
 517         if (err)
 518                 bitmap_print_sb(bitmap);
 519         return err;
 520 }
 521
 522 enum bitmap_mask_op {
 523         MASK_SET,
 524         MASK_UNSET
 525 };
 526
 527 /* record the state of the bitmap in the superblock */
 528 static void bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
 529                                 enum bitmap_mask_op op)
 530 {
 531         bitmap_super_t *sb;
 532         unsigned long flags;
 533
 534         spin_lock_irqsave(&bitmap->lock, flags);
 535         if (!bitmap || !bitmap->sb_page) { /* can't set the state */
 536                 spin_unlock_irqrestore(&bitmap->lock, flags);
 537                 return;
 538         }
 539         page_cache_get(bitmap->sb_page);
 540         spin_unlock_irqrestore(&bitmap->lock, flags);
 541         sb = (bitmap_super_t *)kmap(bitmap->sb_page);
 542         switch (op) {
 543                 case MASK_SET: sb->state |= bits;
 544                                 break;
 545                 case MASK_UNSET: sb->state &= ~bits;
 546                                 break;
 547                 default: BUG();
 548         }
 549         kunmap(bitmap->sb_page);
 550         page_cache_release(bitmap->sb_page);
 551 }
 552
 553 /*
 554  * general bitmap file operations
 555  */
 556
 557 /* calculate the index of the page that contains this bit */
 558 static inline unsigned long file_page_index(unsigned long chunk)
 559 {
 560         return CHUNK_BIT_OFFSET(chunk) >> PAGE_BIT_SHIFT;
 561 }
 562
 563 /* calculate the (bit) offset of this bit within a page */
 564 static inline unsigned long file_page_offset(unsigned long chunk)
 565 {
 566         return CHUNK_BIT_OFFSET(chunk) & (PAGE_BITS - 1);
 567 }
 568
 569 /*
 570  * return a pointer to the page in the filemap that contains the given bit
 571  *
 572  * this lookup is complicated by the fact that the bitmap sb might be exactly
 573  * 1 page (e.g., x86) or less than 1 page -- so the bitmap might start on page
 574  * 0 or page 1
 575  */
 576 static inline struct page *filemap_get_page(struct bitmap *bitmap,
 577                                         unsigned long chunk)
 578 {
 579         return bitmap->filemap[file_page_index(chunk) - file_page_index(0)];
 580 }
 581
 582
 583 static void bitmap_file_unmap(struct bitmap *bitmap)
 584 {
 585         struct page **map, *sb_page;
 586         unsigned long *attr;
 587         int pages;
 588         unsigned long flags;
 589
 590         spin_lock_irqsave(&bitmap->lock, flags);
 591         map = bitmap->filemap;
 592         bitmap->filemap = NULL;
 593         attr = bitmap->filemap_attr;
 594         bitmap->filemap_attr = NULL;
 595         pages = bitmap->file_pages;
 596         bitmap->file_pages = 0;
 597         sb_page = bitmap->sb_page;
 598         bitmap->sb_page = NULL;
 599         spin_unlock_irqrestore(&bitmap->lock, flags);
 600
 601         while (pages--)
 602                 if (map[pages]->index != 0) /* 0 is sb_page, release it below */
 603                         page_cache_release(map[pages]);
 604         kfree(map);
 605         kfree(attr);
 606
 607         if (sb_page)
 608                 page_cache_release(sb_page);
 609 }
 610
 611 static void bitmap_stop_daemons(struct bitmap *bitmap);
 612
 613 /* dequeue the next item in a page list -- don't call from irq context */
 614 static struct page_list *dequeue_page(struct bitmap *bitmap)
 615 {
 616         struct page_list *item = NULL;
 617         struct list_head *head = &bitmap->complete_pages;
 618
 619         spin_lock(&bitmap->write_lock);
 620         if (list_empty(head))
 621                 goto out;
 622         item = list_entry(head->prev, struct page_list, list);
 623         list_del(head->prev);
 624 out:
 625         spin_unlock(&bitmap->write_lock);
 626         return item;
 627 }
 628
 629 static void drain_write_queues(struct bitmap *bitmap)
 630 {
 631         struct page_list *item;
 632
 633         while ((item = dequeue_page(bitmap))) {
 634                 /* don't bother to wait */
 635                 page_cache_release(item->page);
 636                 mempool_free(item, bitmap->write_pool);
 637         }
 638
 639         wake_up(&bitmap->write_wait);
 640 }
 641
 642 static void bitmap_file_put(struct bitmap *bitmap)
 643 {
 644         struct file *file;
 645         struct inode *inode;
 646         unsigned long flags;
 647
 648         spin_lock_irqsave(&bitmap->lock, flags);
 649         file = bitmap->file;
 650         bitmap->file = NULL;
 651         spin_unlock_irqrestore(&bitmap->lock, flags);
 652
 653         bitmap_stop_daemons(bitmap);
 654
 655         drain_write_queues(bitmap);
 656
 657         bitmap_file_unmap(bitmap);
 658
 659         if (file) {
 660                 inode = file->f_mapping->host;
 661                 spin_lock(&inode->i_lock);
 662                 atomic_set(&inode->i_writecount, 1); /* allow writes again */
 663                 spin_unlock(&inode->i_lock);
 664                 fput(file);
 665         }
 666 }
 667
 668
 669 /*
 670  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
 671  * then it is no longer reliable, so we stop using it and we mark the file
 672  * as failed in the superblock
 673  */
 674 static void bitmap_file_kick(struct bitmap *bitmap)
 675 {
 676         char *path, *ptr = NULL;
 677
 678         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET);
 679         bitmap_update_sb(bitmap);
 680
 681         if (bitmap->file) {
 682                 path = kmalloc(PAGE_SIZE, GFP_KERNEL);
 683                 if (path)
 684                         ptr = file_path(bitmap->file, path, PAGE_SIZE);
 685
 686                 printk(KERN_ALERT "%s: kicking failed bitmap file %s from array!\n",
 687                        bmname(bitmap), ptr ? ptr : "");
 688
 689                 kfree(path);
 690         }
 691
 692         bitmap_file_put(bitmap);
 693
 694         return;
 695 }
 696
 697 enum bitmap_page_attr {
 698         BITMAP_PAGE_DIRTY = 1, // there are set bits that need to be synced
 699         BITMAP_PAGE_CLEAN = 2, // there are bits that might need to be cleared
 700         BITMAP_PAGE_NEEDWRITE=4, // there are cleared bits that need to be synced
 701 };
 702
 703 static inline void set_page_attr(struct bitmap *bitmap, struct page *page,
 704                                 enum bitmap_page_attr attr)
 705 {
 706         bitmap->filemap_attr[page->index] |= attr;
 707 }
 708
 709 static inline void clear_page_attr(struct bitmap *bitmap, struct page *page,
 710                                 enum bitmap_page_attr attr)
 711 {
 712         bitmap->filemap_attr[page->index] &= ~attr;
 713 }
 714
 715 static inline unsigned long get_page_attr(struct bitmap *bitmap, struct page *page)
 716 {
 717         return bitmap->filemap_attr[page->index];
 718 }
 719
 720 /*
 721  * bitmap_file_set_bit -- called before performing a write to the md device
 722  * to set (and eventually sync) a particular bit in the bitmap file
 723  *
 724  * we set the bit immediately, then we record the page number so that
 725  * when an unplug occurs, we can flush the dirty pages out to disk
 726  */
 727 static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 728 {
 729         unsigned long bit;
 730         struct page *page;
 731         void *kaddr;
 732         unsigned long chunk = block >> CHUNK_BLOCK_SHIFT(bitmap);
 733
 734         if (!bitmap->filemap) {
 735                 return;
 736         }
 737
 738         page = filemap_get_page(bitmap, chunk);
 739         bit = file_page_offset(chunk);
 740
 741
 742         /* make sure the page stays cached until it gets written out */
 743         if (! (get_page_attr(bitmap, page) & BITMAP_PAGE_DIRTY))
 744                 page_cache_get(page);
 745
 746         /* set the bit */
 747         kaddr = kmap_atomic(page, KM_USER0);
 748         set_bit(bit, kaddr);
 749         kunmap_atomic(kaddr, KM_USER0);
 750         PRINTK("set file bit %lu page %lu\n", bit, page->index);
 751
 752         /* record page number so it gets flushed to disk when unplug occurs */
 753         set_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 754
 755 }
 756
 757 /* this gets called when the md device is ready to unplug its underlying
 758  * (slave) device queues -- before we let any writes go down, we need to
 759  * sync the dirty pages of the bitmap file to disk */
 760 int bitmap_unplug(struct bitmap *bitmap)
 761 {
 762         unsigned long i, attr, flags;
 763         struct page *page;
 764         int wait = 0;
 765
 766         if (!bitmap)
 767                 return 0;
 768
 769         /* look at each page to see if there are any set bits that need to be
 770          * flushed out to disk */
 771         for (i = 0; i < bitmap->file_pages; i++) {
 772                 spin_lock_irqsave(&bitmap->lock, flags);
 773                 if (!bitmap->filemap) {
 774                         spin_unlock_irqrestore(&bitmap->lock, flags);
 775                         return 0;
 776                 }
 777                 page = bitmap->filemap[i];
 778                 attr = get_page_attr(bitmap, page);
 779                 clear_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 780                 clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 781                 if ((attr & BITMAP_PAGE_DIRTY))
 782                         wait = 1;
 783                 spin_unlock_irqrestore(&bitmap->lock, flags);
 784
 785                 if (attr & (BITMAP_PAGE_DIRTY | BITMAP_PAGE_NEEDWRITE))
 786                         if (write_page(bitmap, page, 0))
 787                                 return 1;
 788         }
 789         if (wait) { /* if any writes were performed, we need to wait on them */
 790                 if (bitmap->file) {
 791                         spin_lock_irq(&bitmap->write_lock);
 792                         wait_event_lock_irq(bitmap->write_wait,
 793                                             list_empty(&bitmap->complete_pages), bitmap->write_lock,
 794                                             wake_up_process(bitmap->writeback_daemon->tsk));
 795                         spin_unlock_irq(&bitmap->write_lock);
 796                 } else
 797                         wait_event(bitmap->mddev->sb_wait,
 798                                    atomic_read(&bitmap->mddev->pending_writes)==0);
 799         }
 800         return 0;
 801 }
 802
 803 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset,
 804         unsigned long sectors, int in_sync);
 805 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
 806  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
 807  * memory mapping of the bitmap file
 808  * Special cases:
 809  *   if there's no bitmap file, or if the bitmap file had been
 810  *   previously kicked from the array, we mark all the bits as
 811  *   1's in order to cause a full resync.
 812  */
 813 static int bitmap_init_from_disk(struct bitmap *bitmap, int in_sync)
 814 {
 815         unsigned long i, chunks, index, oldindex, bit;
 816         struct page *page = NULL, *oldpage = NULL;
 817         unsigned long num_pages, bit_cnt = 0;
 818         struct file *file;
 819         unsigned long bytes, offset, dummy;
 820         int outofdate;
 821         int ret = -ENOSPC;
 822
 823         chunks = bitmap->chunks;
 824         file = bitmap->file;
 825
 826         BUG_ON(!file && !bitmap->offset);
 827
 828 #if INJECT_FAULTS_3
 829         outofdate = 1;
 830 #else
 831         outofdate = bitmap->flags & BITMAP_STALE;
 832 #endif
 833         if (outofdate)
 834                 printk(KERN_INFO "%s: bitmap file is out of date, doing full "
 835                         "recovery\n", bmname(bitmap));
 836
 837         bytes = (chunks + 7) / 8;
 838
 839         num_pages = (bytes + sizeof(bitmap_super_t) + PAGE_SIZE - 1) / PAGE_SIZE;
 840
 841         if (file && i_size_read(file->f_mapping->host) < bytes + sizeof(bitmap_super_t)) {
 842                 printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
 843                         bmname(bitmap),
 844                         (unsigned long) i_size_read(file->f_mapping->host),
 845                         bytes + sizeof(bitmap_super_t));
 846                 goto out;
 847         }
 848
 849         ret = -ENOMEM;
 850
 851         bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
 852         if (!bitmap->filemap)
 853                 goto out;
 854
 855         bitmap->filemap_attr = kmalloc(sizeof(long) * num_pages, GFP_KERNEL);
 856         if (!bitmap->filemap_attr)
 857                 goto out;
 858
 859         memset(bitmap->filemap_attr, 0, sizeof(long) * num_pages);
 860
 861         oldindex = ~0L;
 862
 863         for (i = 0; i < chunks; i++) {
 864                 index = file_page_index(i);
 865                 bit = file_page_offset(i);
 866                 if (index != oldindex) { /* this is a new page, read it in */
 867                         /* unmap the old page, we're done with it */
 868                         if (oldpage != NULL)
 869                                 kunmap(oldpage);
 870                         if (index == 0) {
 871                                 /*
 872                                  * if we're here then the superblock page
 873                                  * contains some bits (PAGE_SIZE != sizeof sb)
 874                                  * we've already read it in, so just use it
 875                                  */
 876                                 page = bitmap->sb_page;
 877                                 offset = sizeof(bitmap_super_t);
 878                         } else if (file) {
 879                                 page = read_page(file, index, &dummy);
 880                                 offset = 0;
 881                         } else {
 882                                 page = read_sb_page(bitmap->mddev, bitmap->offset, index);
 883                                 offset = 0;
 884                         }
 885                         if (IS_ERR(page)) { /* read error */
 886                                 ret = PTR_ERR(page);
 887                                 goto out;
 888                         }
 889
 890                         oldindex = index;
 891                         oldpage = page;
 892                         kmap(page);
 893
 894                         if (outofdate) {
 895                                 /*
 896                                  * if bitmap is out of date, dirty the
 897                                  * whole page and write it out
 898                                  */
 899                                 memset(page_address(page) + offset, 0xff,
 900                                         PAGE_SIZE - offset);
 901                                 ret = write_page(bitmap, page, 1);
 902                                 if (ret) {
 903                                         kunmap(page);
 904                                         /* release, page not in filemap yet */
 905                                         page_cache_release(page);
 906                                         goto out;
 907                                 }
 908                         }
 909
 910                         bitmap->filemap[bitmap->file_pages++] = page;
 911                 }
 912                 if (test_bit(bit, page_address(page))) {
 913                         /* if the disk bit is set, set the memory bit */
 914                         bitmap_set_memory_bits(bitmap,
 915                                         i << CHUNK_BLOCK_SHIFT(bitmap), 1, in_sync);
 916                         bit_cnt++;
 917                 }
 918         }
 919
 920         /* everything went OK */
 921         ret = 0;
 922         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_UNSET);
 923
 924         if (page) /* unmap the last page */
 925                 kunmap(page);
 926
 927         if (bit_cnt) { /* Kick recovery if any bits were set */
 928                 set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
 929                 md_wakeup_thread(bitmap->mddev->thread);
 930         }
 931
 932 out:
 933         printk(KERN_INFO "%s: bitmap initialized from disk: "
 934                 "read %lu/%lu pages, set %lu bits, status: %d\n",
 935                 bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt, ret);
 936
 937         return ret;
 938 }
 939
 940 void bitmap_write_all(struct bitmap *bitmap)
 941 {
 942         /* We don't actually write all bitmap blocks here,
 943          * just flag them as needing to be written
 944          */
 945
 946         unsigned long chunks = bitmap->chunks;
 947         unsigned long bytes = (chunks+7)/8 + sizeof(bitmap_super_t);
 948         unsigned long num_pages = (bytes + PAGE_SIZE-1) / PAGE_SIZE;
 949         while (num_pages--)
 950                 bitmap->filemap_attr[num_pages] |= BITMAP_PAGE_NEEDWRITE;
 951 }
 952
 953
 954 static void bitmap_count_page(struct bitmap *bitmap, sector_t offset, int inc)
 955 {
 956         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
 957         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
 958         bitmap->bp[page].count += inc;
 959 /*
 960         if (page == 0) printk("count page 0, offset %llu: %d gives %d\n",
 961                               (unsigned long long)offset, inc, bitmap->bp[page].count);
 962 */
 963         bitmap_checkfree(bitmap, page);
 964 }
 965 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
 966                                             sector_t offset, int *blocks,
 967                                             int create);
 968
 969 /*
 970  * bitmap daemon -- periodically wakes up to clean bits and flush pages
 971  *                      out to disk
 972  */
 973
 974 int bitmap_daemon_work(struct bitmap *bitmap)
 975 {
 976         unsigned long j;
 977         unsigned long flags;
 978         struct page *page = NULL, *lastpage = NULL;
 979         int err = 0;
 980         int blocks;
 981         int attr;
 982
 983         if (bitmap == NULL)
 984                 return 0;
 985         if (time_before(jiffies, bitmap->daemon_lastrun + bitmap->daemon_sleep*HZ))
 986                 return 0;
 987         bitmap->daemon_lastrun = jiffies;
 988
 989         for (j = 0; j < bitmap->chunks; j++) {
 990                 bitmap_counter_t *bmc;
 991                 spin_lock_irqsave(&bitmap->lock, flags);
 992                 if (!bitmap->filemap) {
 993                         /* error or shutdown */
 994                         spin_unlock_irqrestore(&bitmap->lock, flags);
 995                         break;
 996                 }
 997
 998                 page = filemap_get_page(bitmap, j);
 999
1000                 if (page != lastpage) {
1001                         /* skip this page unless it's marked as needing cleaning */
1002                         if (!((attr=get_page_attr(bitmap, page)) & BITMAP_PAGE_CLEAN)) {
1003                                 if (attr & BITMAP_PAGE_NEEDWRITE) {
1004                                         page_cache_get(page);
1005                                         clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
1006                                 }
1007                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1008                                 if (attr & BITMAP_PAGE_NEEDWRITE) {
1009                                         if (write_page(bitmap, page, 0))
1010                                                 bitmap_file_kick(bitmap);
1011                                         page_cache_release(page);
1012                                 }
1013                                 continue;
1014                         }
1015
1016                         /* grab the new page, sync and release the old */
1017                         page_cache_get(page);
1018                         if (lastpage != NULL) {
1019                                 if (get_page_attr(bitmap, lastpage) & BITMAP_PAGE_NEEDWRITE) {
1020                                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1021                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1022                                         err = write_page(bitmap, lastpage, 0);
1023                                 } else {
1024                                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1025                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1026                                 }
1027                                 kunmap(lastpage);
1028                                 page_cache_release(lastpage);
1029                                 if (err)
1030                                         bitmap_file_kick(bitmap);
1031                         } else
1032                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1033                         lastpage = page;
1034                         kmap(page);
1035 /*
1036                         printk("bitmap clean at page %lu\n", j);
1037 */
1038                         spin_lock_irqsave(&bitmap->lock, flags);
1039                         clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1040                 }
1041                 bmc = bitmap_get_counter(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
1042                                         &blocks, 0);
1043                 if (bmc) {
1044 /*
1045   if (j < 100) printk("bitmap: j=%lu, *bmc = 0x%x\n", j, *bmc);
1046 */
1047                         if (*bmc == 2) {
1048                                 *bmc=1; /* maybe clear the bit next time */
1049                                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1050                         } else if (*bmc == 1) {
1051                                 /* we can clear the bit */
1052                                 *bmc = 0;
1053                                 bitmap_count_page(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
1054                                                   -1);
1055
1056                                 /* clear the bit */
1057                                 clear_bit(file_page_offset(j), page_address(page));
1058                         }
1059                 }
1060                 spin_unlock_irqrestore(&bitmap->lock, flags);
1061         }
1062
1063         /* now sync the final page */
1064         if (lastpage != NULL) {
1065                 kunmap(lastpage);
1066                 spin_lock_irqsave(&bitmap->lock, flags);
1067                 if (get_page_attr(bitmap, lastpage) &BITMAP_PAGE_NEEDWRITE) {
1068                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1069                         spin_unlock_irqrestore(&bitmap->lock, flags);
1070                         err = write_page(bitmap, lastpage, 0);
1071                 } else {
1072                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1073                         spin_unlock_irqrestore(&bitmap->lock, flags);
1074                 }
1075
1076                 page_cache_release(lastpage);
1077         }
1078
1079         return err;
1080 }
1081
1082 static void daemon_exit(struct bitmap *bitmap, mdk_thread_t **daemon)
1083 {
1084         mdk_thread_t *dmn;
1085         unsigned long flags;
1086
1087         /* if no one is waiting on us, we'll free the md thread struct
1088          * and exit, otherwise we let the waiter clean things up */
1089         spin_lock_irqsave(&bitmap->lock, flags);
1090         if ((dmn = *daemon)) { /* no one is waiting, cleanup and exit */
1091                 *daemon = NULL;
1092                 spin_unlock_irqrestore(&bitmap->lock, flags);
1093                 kfree(dmn);
1094                 complete_and_exit(NULL, 0); /* do_exit not exported */
1095         }
1096         spin_unlock_irqrestore(&bitmap->lock, flags);
1097 }
1098
1099 static void bitmap_writeback_daemon(mddev_t *mddev)
1100 {
1101         struct bitmap *bitmap = mddev->bitmap;
1102         struct page *page;
1103         struct page_list *item;
1104         int err = 0;
1105
1106         if (signal_pending(current)) {
1107                 printk(KERN_INFO
1108                        "%s: bitmap writeback daemon got signal, exiting...\n",
1109                        bmname(bitmap));
1110                 err = -EINTR;
1111                 goto out;
1112         }
1113
1114         PRINTK("%s: bitmap writeback daemon woke up...\n", bmname(bitmap));
1115         /* wait on bitmap page writebacks */
1116         while ((item = dequeue_page(bitmap))) {
1117                 page = item->page;
1118                 mempool_free(item, bitmap->write_pool);
1119                 PRINTK("wait on page writeback: %p\n", page);
1120                 wait_on_page_writeback(page);
1121                 PRINTK("finished page writeback: %p\n", page);
1122
1123                 err = PageError(page);
1124                 page_cache_release(page);
1125                 if (err) {
1126                         printk(KERN_WARNING "%s: bitmap file writeback "
1127                                "failed (page %lu): %d\n",
1128                                bmname(bitmap), page->index, err);
1129                         bitmap_file_kick(bitmap);
1130                         goto out;
1131                 }
1132         }
1133  out:
1134         wake_up(&bitmap->write_wait);
1135         if (err) {
1136                 printk(KERN_INFO "%s: bitmap writeback daemon exiting (%d)\n",
1137                        bmname(bitmap), err);
1138                 daemon_exit(bitmap, &bitmap->writeback_daemon);
1139         }
1140 }
1141
1142 static int bitmap_start_daemon(struct bitmap *bitmap, mdk_thread_t **ptr,
1143                                 void (*func)(mddev_t *), char *name)
1144 {
1145         mdk_thread_t *daemon;
1146         unsigned long flags;
1147         char namebuf[32];
1148
1149         spin_lock_irqsave(&bitmap->lock, flags);
1150         *ptr = NULL;
1151
1152         if (!bitmap->file) /* no need for daemon if there's no backing file */
1153                 goto out_unlock;
1154
1155         spin_unlock_irqrestore(&bitmap->lock, flags);
1156
1157 #if INJECT_FATAL_FAULT_2
1158         daemon = NULL;
1159 #else
1160         sprintf(namebuf, "%%s_%s", name);
1161         daemon = md_register_thread(func, bitmap->mddev, namebuf);
1162 #endif
1163         if (!daemon) {
1164                 printk(KERN_ERR "%s: failed to start bitmap daemon\n",
1165                         bmname(bitmap));
1166                 return -ECHILD;
1167         }
1168
1169         spin_lock_irqsave(&bitmap->lock, flags);
1170         *ptr = daemon;
1171
1172         md_wakeup_thread(daemon); /* start it running */
1173
1174         PRINTK("%s: %s daemon (pid %d) started...\n",
1175                 bmname(bitmap), name, daemon->tsk->pid);
1176 out_unlock:
1177         spin_unlock_irqrestore(&bitmap->lock, flags);
1178         return 0;
1179 }
1180
1181 static int bitmap_start_daemons(struct bitmap *bitmap)
1182 {
1183         int err = bitmap_start_daemon(bitmap, &bitmap->writeback_daemon,
1184                                         bitmap_writeback_daemon, "bitmap_wb");
1185         return err;
1186 }
1187
1188 static void bitmap_stop_daemon(struct bitmap *bitmap, mdk_thread_t **ptr)
1189 {
1190         mdk_thread_t *daemon;
1191         unsigned long flags;
1192
1193         spin_lock_irqsave(&bitmap->lock, flags);
1194         daemon = *ptr;
1195         *ptr = NULL;
1196         spin_unlock_irqrestore(&bitmap->lock, flags);
1197         if (daemon)
1198                 md_unregister_thread(daemon); /* destroy the thread */
1199 }
1200
1201 static void bitmap_stop_daemons(struct bitmap *bitmap)
1202 {
1203         /* the daemons can't stop themselves... they'll just exit instead... */
1204         if (bitmap->writeback_daemon &&
1205             current->pid != bitmap->writeback_daemon->tsk->pid)
1206                 bitmap_stop_daemon(bitmap, &bitmap->writeback_daemon);
1207 }
1208
1209 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1210                                             sector_t offset, int *blocks,
1211                                             int create)
1212 {
1213         /* If 'create', we might release the lock and reclaim it.
1214          * The lock must have been taken with interrupts enabled.
1215          * If !create, we don't release the lock.
1216          */
1217         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1218         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1219         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1220         sector_t csize;
1221
1222         if (bitmap_checkpage(bitmap, page, create) < 0) {
1223                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1224                 *blocks = csize - (offset & (csize- 1));
1225                 return NULL;
1226         }
1227         /* now locked ... */
1228
1229         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1230                 /* should we use the first or second counter field
1231                  * of the hijacked pointer? */
1232                 int hi = (pageoff > PAGE_COUNTER_MASK);
1233                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap) +
1234                                           PAGE_COUNTER_SHIFT - 1);
1235                 *blocks = csize - (offset & (csize- 1));
1236                 return  &((bitmap_counter_t *)
1237                           &bitmap->bp[page].map)[hi];
1238         } else { /* page is allocated */
1239                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1240                 *blocks = csize - (offset & (csize- 1));
1241                 return (bitmap_counter_t *)
1242                         &(bitmap->bp[page].map[pageoff]);
1243         }
1244 }
1245
1246 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors)
1247 {
1248         if (!bitmap) return 0;
1249         while (sectors) {
1250                 int blocks;
1251                 bitmap_counter_t *bmc;
1252
1253                 spin_lock_irq(&bitmap->lock);
1254                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 1);
1255                 if (!bmc) {
1256                         spin_unlock_irq(&bitmap->lock);
1257                         return 0;
1258                 }
1259
1260                 switch(*bmc) {
1261                 case 0:
1262                         bitmap_file_set_bit(bitmap, offset);
1263                         bitmap_count_page(bitmap,offset, 1);
1264                         blk_plug_device(bitmap->mddev->queue);
1265                         /* fall through */
1266                 case 1:
1267                         *bmc = 2;
1268                 }
1269                 if ((*bmc & COUNTER_MAX) == COUNTER_MAX) BUG();
1270                 (*bmc)++;
1271
1272                 spin_unlock_irq(&bitmap->lock);
1273
1274                 offset += blocks;
1275                 if (sectors > blocks)
1276                         sectors -= blocks;
1277                 else sectors = 0;
1278         }
1279         return 0;
1280 }
1281
1282 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1283                      int success)
1284 {
1285         if (!bitmap) return;
1286         while (sectors) {
1287                 int blocks;
1288                 unsigned long flags;
1289                 bitmap_counter_t *bmc;
1290
1291                 spin_lock_irqsave(&bitmap->lock, flags);
1292                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 0);
1293                 if (!bmc) {
1294                         spin_unlock_irqrestore(&bitmap->lock, flags);
1295                         return;
1296                 }
1297
1298                 if (!success && ! (*bmc & NEEDED_MASK))
1299                         *bmc |= NEEDED_MASK;
1300
1301                 (*bmc)--;
1302                 if (*bmc <= 2) {
1303                         set_page_attr(bitmap,
1304                                       filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1305                                       BITMAP_PAGE_CLEAN);
1306                 }
1307                 spin_unlock_irqrestore(&bitmap->lock, flags);
1308                 offset += blocks;
1309                 if (sectors > blocks)
1310                         sectors -= blocks;
1311                 else sectors = 0;
1312         }
1313 }
1314
1315 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks)
1316 {
1317         bitmap_counter_t *bmc;
1318         int rv;
1319         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1320                 *blocks = 1024;
1321                 return 1; /* always resync if no bitmap */
1322         }
1323         spin_lock_irq(&bitmap->lock);
1324         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1325         rv = 0;
1326         if (bmc) {
1327                 /* locked */
1328                 if (RESYNC(*bmc))
1329                         rv = 1;
1330                 else if (NEEDED(*bmc)) {
1331                         rv = 1;
1332                         *bmc |= RESYNC_MASK;
1333                         *bmc &= ~NEEDED_MASK;
1334                 }
1335         }
1336         spin_unlock_irq(&bitmap->lock);
1337         return rv;
1338 }
1339
1340 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int aborted)
1341 {
1342         bitmap_counter_t *bmc;
1343         unsigned long flags;
1344 /*
1345         if (offset == 0) printk("bitmap_end_sync 0 (%d)\n", aborted);
1346 */      if (bitmap == NULL) {
1347                 *blocks = 1024;
1348                 return;
1349         }
1350         spin_lock_irqsave(&bitmap->lock, flags);
1351         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1352         if (bmc == NULL)
1353                 goto unlock;
1354         /* locked */
1355 /*
1356         if (offset == 0) printk("bitmap_end sync found 0x%x, blocks %d\n", *bmc, *blocks);
1357 */
1358         if (RESYNC(*bmc)) {
1359                 *bmc &= ~RESYNC_MASK;
1360
1361                 if (!NEEDED(*bmc) && aborted)
1362                         *bmc |= NEEDED_MASK;
1363                 else {
1364                         if (*bmc <= 2) {
1365                                 set_page_attr(bitmap,
1366                                               filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1367                                               BITMAP_PAGE_CLEAN);
1368                         }
1369                 }
1370         }
1371  unlock:
1372         spin_unlock_irqrestore(&bitmap->lock, flags);
1373 }
1374
1375 void bitmap_close_sync(struct bitmap *bitmap)
1376 {
1377         /* Sync has finished, and any bitmap chunks that weren't synced
1378          * properly have been aborted.  It remains to us to clear the
1379          * RESYNC bit wherever it is still on
1380          */
1381         sector_t sector = 0;
1382         int blocks;
1383         if (!bitmap) return;
1384         while (sector < bitmap->mddev->resync_max_sectors) {
1385                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1386 /*
1387                 if (sector < 500) printk("bitmap_close_sync: sec %llu blks %d\n",
1388                                          (unsigned long long)sector, blocks);
1389 */              sector += blocks;
1390         }
1391 }
1392
1393 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset,
1394                                    unsigned long sectors, int in_sync)
1395 {
1396         /* For each chunk covered by any of these sectors, set the
1397          * counter to 1 and set resync_needed unless in_sync.  They should all
1398          * be 0 at this point
1399          */
1400         while (sectors) {
1401                 int secs;
1402                 bitmap_counter_t *bmc;
1403                 spin_lock_irq(&bitmap->lock);
1404                 bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
1405                 if (!bmc) {
1406                         spin_unlock_irq(&bitmap->lock);
1407                         return;
1408                 }
1409                 if (! *bmc) {
1410                         struct page *page;
1411                         *bmc = 1 | (in_sync? 0 : NEEDED_MASK);
1412                         bitmap_count_page(bitmap, offset, 1);
1413                         page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));
1414                         set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1415                 }
1416                 spin_unlock_irq(&bitmap->lock);
1417                 if (sectors > secs)
1418                         sectors -= secs;
1419                 else
1420                         sectors = 0;
1421         }
1422 }
1423
1424 /* dirty the entire bitmap */
1425 int bitmap_setallbits(struct bitmap *bitmap)
1426 {
1427         unsigned long flags;
1428         unsigned long j;
1429
1430         /* dirty the in-memory bitmap */
1431         bitmap_set_memory_bits(bitmap, 0, bitmap->chunks << CHUNK_BLOCK_SHIFT(bitmap), 1);
1432
1433         /* dirty the bitmap file */
1434         for (j = 0; j < bitmap->file_pages; j++) {
1435                 struct page *page = bitmap->filemap[j];
1436
1437                 spin_lock_irqsave(&bitmap->lock, flags);
1438                 page_cache_get(page);
1439                 spin_unlock_irqrestore(&bitmap->lock, flags);
1440                 memset(kmap(page), 0xff, PAGE_SIZE);
1441                 kunmap(page);
1442                 if (write_page(bitmap, page, 0))
1443                         return 1;
1444         }
1445
1446         return 0;
1447 }
1448
1449 /*
1450  * free memory that was allocated
1451  */
1452 void bitmap_destroy(mddev_t *mddev)
1453 {
1454         unsigned long k, pages;
1455         struct bitmap_page *bp;
1456         struct bitmap *bitmap = mddev->bitmap;
1457
1458         if (!bitmap) /* there was no bitmap */
1459                 return;
1460
1461         mddev->bitmap = NULL; /* disconnect from the md device */
1462
1463         /* release the bitmap file and kill the daemon */
1464         bitmap_file_put(bitmap);
1465
1466         bp = bitmap->bp;
1467         pages = bitmap->pages;
1468
1469         /* free all allocated memory */
1470
1471         mempool_destroy(bitmap->write_pool);
1472
1473         if (bp) /* deallocate the page memory */
1474                 for (k = 0; k < pages; k++)
1475                         if (bp[k].map && !bp[k].hijacked)
1476                                 kfree(bp[k].map);
1477         kfree(bp);
1478         kfree(bitmap);
1479 }
1480
1481 /*
1482  * initialize the bitmap structure
1483  * if this returns an error, bitmap_destroy must be called to do clean up
1484  */
1485 int bitmap_create(mddev_t *mddev)
1486 {
1487         struct bitmap *bitmap;
1488         unsigned long blocks = mddev->resync_max_sectors;
1489         unsigned long chunks;
1490         unsigned long pages;
1491         struct file *file = mddev->bitmap_file;
1492         int err;
1493
1494         BUG_ON(sizeof(bitmap_super_t) != 256);
1495
1496         if (!file && !mddev->bitmap_offset) /* bitmap disabled, nothing to do */
1497                 return 0;
1498
1499         BUG_ON(file && mddev->bitmap_offset);
1500
1501         bitmap = kmalloc(sizeof(*bitmap), GFP_KERNEL);
1502         if (!bitmap)
1503                 return -ENOMEM;
1504
1505         memset(bitmap, 0, sizeof(*bitmap));
1506
1507         spin_lock_init(&bitmap->lock);
1508         bitmap->mddev = mddev;
1509         mddev->bitmap = bitmap;
1510
1511         spin_lock_init(&bitmap->write_lock);
1512         INIT_LIST_HEAD(&bitmap->complete_pages);
1513         init_waitqueue_head(&bitmap->write_wait);
1514         bitmap->write_pool = mempool_create(WRITE_POOL_SIZE, write_pool_alloc,
1515                                 write_pool_free, NULL);
1516         if (!bitmap->write_pool)
1517                 return -ENOMEM;
1518
1519         bitmap->file = file;
1520         bitmap->offset = mddev->bitmap_offset;
1521         if (file) get_file(file);
1522         /* read superblock from bitmap file (this sets bitmap->chunksize) */
1523         err = bitmap_read_sb(bitmap);
1524         if (err)
1525                 return err;
1526
1527         bitmap->chunkshift = find_first_bit(&bitmap->chunksize,
1528                                         sizeof(bitmap->chunksize));
1529
1530         /* now that chunksize and chunkshift are set, we can use these macros */
1531         chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) /
1532                         CHUNK_BLOCK_RATIO(bitmap);
1533         pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
1534
1535         BUG_ON(!pages);
1536
1537         bitmap->chunks = chunks;
1538         bitmap->pages = pages;
1539         bitmap->missing_pages = pages;
1540         bitmap->counter_bits = COUNTER_BITS;
1541
1542         bitmap->syncchunk = ~0UL;
1543
1544 #if INJECT_FATAL_FAULT_1
1545         bitmap->bp = NULL;
1546 #else
1547         bitmap->bp = kmalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
1548 #endif
1549         if (!bitmap->bp)
1550                 return -ENOMEM;
1551         memset(bitmap->bp, 0, pages * sizeof(*bitmap->bp));
1552
1553         bitmap->flags |= BITMAP_ACTIVE;
1554
1555         /* now that we have some pages available, initialize the in-memory
1556          * bitmap from the on-disk bitmap */
1557         err = bitmap_init_from_disk(bitmap, mddev->recovery_cp == MaxSector);
1558         if (err)
1559                 return err;
1560
1561         printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
1562                 pages, bmname(bitmap));
1563
1564         /* kick off the bitmap daemons */
1565         err = bitmap_start_daemons(bitmap);
1566         if (err)
1567                 return err;
1568         return bitmap_update_sb(bitmap);
1569 }
1570
1571 /* the bitmap API -- for raid personalities */
1572 EXPORT_SYMBOL(bitmap_startwrite);
1573 EXPORT_SYMBOL(bitmap_endwrite);
1574 EXPORT_SYMBOL(bitmap_start_sync);
1575 EXPORT_SYMBOL(bitmap_end_sync);
1576 EXPORT_SYMBOL(bitmap_unplug);
1577 EXPORT_SYMBOL(bitmap_close_sync);
1578 EXPORT_SYMBOL(bitmap_daemon_work);