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  */
  11
  12 /*
  13  * Still to do:
  14  *
  15  * flush after percent set rather than just time based. (maybe both).
  16  * wait if count gets too high, wake when it drops to half.
  17  * allow bitmap to be mirrored with superblock (before or after...)
  18  * allow hot-add to re-instate a current device.
  19  * allow hot-add of bitmap after quiessing device
  20  */
  21
  22 #include <linux/module.h>
  23 #include <linux/errno.h>
  24 #include <linux/slab.h>
  25 #include <linux/init.h>
  26 #include <linux/config.h>
  27 #include <linux/timer.h>
  28 #include <linux/sched.h>
  29 #include <linux/list.h>
  30 #include <linux/file.h>
  31 #include <linux/mount.h>
  32 #include <linux/buffer_head.h>
  33 #include <linux/raid/md.h>
  34 #include <linux/raid/bitmap.h>
  35
  36 /* debug macros */
  37
  38 #define DEBUG 0
  39
  40 #if DEBUG
  41 /* these are for debugging purposes only! */
  42
  43 /* define one and only one of these */
  44 #define INJECT_FAULTS_1 0 /* cause bitmap_alloc_page to fail always */
  45 #define INJECT_FAULTS_2 0 /* cause bitmap file to be kicked when first bit set*/
  46 #define INJECT_FAULTS_3 0 /* treat bitmap file as kicked at init time */
  47 #define INJECT_FAULTS_4 0 /* undef */
  48 #define INJECT_FAULTS_5 0 /* undef */
  49 #define INJECT_FAULTS_6 0
  50
  51 /* if these are defined, the driver will fail! debug only */
  52 #define INJECT_FATAL_FAULT_1 0 /* fail kmalloc, causing bitmap_create to fail */
  53 #define INJECT_FATAL_FAULT_2 0 /* undef */
  54 #define INJECT_FATAL_FAULT_3 0 /* undef */
  55 #endif
  56
  57 //#define DPRINTK PRINTK /* set this NULL to avoid verbose debug output */
  58 #define DPRINTK(x...) do { } while(0)
  59
  60 #ifndef PRINTK
  61 #  if DEBUG > 0
  62 #    define PRINTK(x...) printk(KERN_DEBUG x)
  63 #  else
  64 #    define PRINTK(x...)
  65 #  endif
  66 #endif
  67
  68 static inline char * bmname(struct bitmap *bitmap)
  69 {
  70         return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
  71 }
  72
  73
  74 /*
  75  * test if the bitmap is active
  76  */
  77 int bitmap_active(struct bitmap *bitmap)
  78 {
  79         unsigned long flags;
  80         int res = 0;
  81
  82         if (!bitmap)
  83                 return res;
  84         spin_lock_irqsave(&bitmap->lock, flags);
  85         res = bitmap->flags & BITMAP_ACTIVE;
  86         spin_unlock_irqrestore(&bitmap->lock, flags);
  87         return res;
  88 }
  89
  90 #define WRITE_POOL_SIZE 256
  91
  92 /*
  93  * just a placeholder - calls kmalloc for bitmap pages
  94  */
  95 static unsigned char *bitmap_alloc_page(struct bitmap *bitmap)
  96 {
  97         unsigned char *page;
  98
  99 #ifdef INJECT_FAULTS_1
 100         page = NULL;
 101 #else
 102         page = kmalloc(PAGE_SIZE, GFP_NOIO);
 103 #endif
 104         if (!page)
 105                 printk("%s: bitmap_alloc_page FAILED\n", bmname(bitmap));
 106         else
 107                 PRINTK("%s: bitmap_alloc_page: allocated page at %p\n",
 108                         bmname(bitmap), page);
 109         return page;
 110 }
 111
 112 /*
 113  * for now just a placeholder -- just calls kfree for bitmap pages
 114  */
 115 static void bitmap_free_page(struct bitmap *bitmap, unsigned char *page)
 116 {
 117         PRINTK("%s: bitmap_free_page: free page %p\n", bmname(bitmap), page);
 118         kfree(page);
 119 }
 120
 121 /*
 122  * check a page and, if necessary, allocate it (or hijack it if the alloc fails)
 123  *
 124  * 1) check to see if this page is allocated, if it's not then try to alloc
 125  * 2) if the alloc fails, set the page's hijacked flag so we'll use the
 126  *    page pointer directly as a counter
 127  *
 128  * if we find our page, we increment the page's refcount so that it stays
 129  * allocated while we're using it
 130  */
 131 static int bitmap_checkpage(struct bitmap *bitmap, unsigned long page, int create)
 132 {
 133         unsigned char *mappage;
 134
 135         if (page >= bitmap->pages) {
 136                 printk(KERN_ALERT
 137                         "%s: invalid bitmap page request: %lu (> %lu)\n",
 138                         bmname(bitmap), page, bitmap->pages-1);
 139                 return -EINVAL;
 140         }
 141
 142
 143         if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
 144                 return 0;
 145
 146         if (bitmap->bp[page].map) /* page is already allocated, just return */
 147                 return 0;
 148
 149         if (!create)
 150                 return -ENOENT;
 151
 152         spin_unlock_irq(&bitmap->lock);
 153
 154         /* this page has not been allocated yet */
 155
 156         if ((mappage = bitmap_alloc_page(bitmap)) == NULL) {
 157                 PRINTK("%s: bitmap map page allocation failed, hijacking\n",
 158                         bmname(bitmap));
 159                 /* failed - set the hijacked flag so that we can use the
 160                  * pointer as a counter */
 161                 spin_lock_irq(&bitmap->lock);
 162                 if (!bitmap->bp[page].map)
 163                         bitmap->bp[page].hijacked = 1;
 164                 goto out;
 165         }
 166
 167         /* got a page */
 168
 169         spin_lock_irq(&bitmap->lock);
 170
 171         /* recheck the page */
 172
 173         if (bitmap->bp[page].map || bitmap->bp[page].hijacked) {
 174                 /* somebody beat us to getting the page */
 175                 bitmap_free_page(bitmap, mappage);
 176                 return 0;
 177         }
 178
 179         /* no page was in place and we have one, so install it */
 180
 181         memset(mappage, 0, PAGE_SIZE);
 182         bitmap->bp[page].map = mappage;
 183         bitmap->missing_pages--;
 184 out:
 185         return 0;
 186 }
 187
 188
 189 /* if page is completely empty, put it back on the free list, or dealloc it */
 190 /* if page was hijacked, unmark the flag so it might get alloced next time */
 191 /* Note: lock should be held when calling this */
 192 static void bitmap_checkfree(struct bitmap *bitmap, unsigned long page)
 193 {
 194         char *ptr;
 195
 196         if (bitmap->bp[page].count) /* page is still busy */
 197                 return;
 198
 199         /* page is no longer in use, it can be released */
 200
 201         if (bitmap->bp[page].hijacked) { /* page was hijacked, undo this now */
 202                 bitmap->bp[page].hijacked = 0;
 203                 bitmap->bp[page].map = NULL;
 204                 return;
 205         }
 206
 207         /* normal case, free the page */
 208
 209 #if 0
 210 /* actually ... let's not.  We will probably need the page again exactly when
 211  * memory is tight and we are flusing to disk
 212  */
 213         return;
 214 #else
 215         ptr = bitmap->bp[page].map;
 216         bitmap->bp[page].map = NULL;
 217         bitmap->missing_pages++;
 218         bitmap_free_page(bitmap, ptr);
 219         return;
 220 #endif
 221 }
 222
 223
 224 /*
 225  * bitmap file handling - read and write the bitmap file and its superblock
 226  */
 227
 228 /* copy the pathname of a file to a buffer */
 229 char *file_path(struct file *file, char *buf, int count)
 230 {
 231         struct dentry *d;
 232         struct vfsmount *v;
 233
 234         if (!buf)
 235                 return NULL;
 236
 237         d = file->f_dentry;
 238         v = file->f_vfsmnt;
 239
 240         buf = d_path(d, v, buf, count);
 241
 242         return IS_ERR(buf) ? NULL : buf;
 243 }
 244
 245 /*
 246  * basic page I/O operations
 247  */
 248
 249 /* IO operations when bitmap is stored near all superblocks */
 250 static struct page *read_sb_page(mddev_t *mddev, long offset, unsigned long index)
 251 {
 252         /* choose a good rdev and read the page from there */
 253
 254         mdk_rdev_t *rdev;
 255         struct list_head *tmp;
 256         struct page *page = alloc_page(GFP_KERNEL);
 257         sector_t target;
 258
 259         if (!page)
 260                 return ERR_PTR(-ENOMEM);
 261
 262         ITERATE_RDEV(mddev, rdev, tmp) {
 263                 if (! test_bit(In_sync, &rdev->flags)
 264                     || test_bit(Faulty, &rdev->flags))
 265                         continue;
 266
 267                 target = (rdev->sb_offset << 1) + offset + index * (PAGE_SIZE/512);
 268
 269                 if (sync_page_io(rdev->bdev, target, PAGE_SIZE, page, READ)) {
 270                         page->index = index;
 271                         return page;
 272                 }
 273         }
 274         return ERR_PTR(-EIO);
 275
 276 }
 277
 278 static int write_sb_page(mddev_t *mddev, long offset, struct page *page, int wait)
 279 {
 280         mdk_rdev_t *rdev;
 281         struct list_head *tmp;
 282
 283         ITERATE_RDEV(mddev, rdev, tmp)
 284                 if (test_bit(In_sync, &rdev->flags)
 285                     && !test_bit(Faulty, &rdev->flags))
 286                         md_super_write(mddev, rdev,
 287                                        (rdev->sb_offset<<1) + offset
 288                                        + page->index * (PAGE_SIZE/512),
 289                                        PAGE_SIZE,
 290                                        page);
 291
 292         if (wait)
 293                 md_super_wait(mddev);
 294         return 0;
 295 }
 296
 297 /*
 298  * write out a page to a file
 299  */
 300 static int write_page(struct bitmap *bitmap, struct page *page, int wait)
 301 {
 302         int ret = -ENOMEM;
 303
 304         if (bitmap->file == NULL)
 305                 return write_sb_page(bitmap->mddev, bitmap->offset, page, wait);
 306
 307         flush_dcache_page(page); /* make sure visible to anyone reading the file */
 308
 309         if (wait)
 310                 lock_page(page);
 311         else {
 312                 if (TestSetPageLocked(page))
 313                         return -EAGAIN; /* already locked */
 314                 if (PageWriteback(page)) {
 315                         unlock_page(page);
 316                         return -EAGAIN;
 317                 }
 318         }
 319
 320         ret = page->mapping->a_ops->prepare_write(bitmap->file, page, 0, PAGE_SIZE);
 321         if (!ret)
 322                 ret = page->mapping->a_ops->commit_write(bitmap->file, page, 0,
 323                         PAGE_SIZE);
 324         if (ret) {
 325                 unlock_page(page);
 326                 return ret;
 327         }
 328
 329         set_page_dirty(page); /* force it to be written out */
 330
 331         if (!wait) {
 332                 /* add to list to be waited for */
 333                 struct page_list *item = mempool_alloc(bitmap->write_pool, GFP_NOIO);
 334                 item->page = page;
 335                 get_page(page);
 336                 spin_lock(&bitmap->write_lock);
 337                 list_add(&item->list, &bitmap->complete_pages);
 338                 spin_unlock(&bitmap->write_lock);
 339         }
 340         return write_one_page(page, wait);
 341 }
 342
 343 /* read a page from a file, pinning it into cache, and return bytes_read */
 344 static struct page *read_page(struct file *file, unsigned long index,
 345                                         unsigned long *bytes_read)
 346 {
 347         struct inode *inode = file->f_mapping->host;
 348         struct page *page = NULL;
 349         loff_t isize = i_size_read(inode);
 350         unsigned long end_index = isize >> PAGE_SHIFT;
 351
 352         PRINTK("read bitmap file (%dB @ %Lu)\n", (int)PAGE_SIZE,
 353                         (unsigned long long)index << PAGE_SHIFT);
 354
 355         page = read_cache_page(inode->i_mapping, index,
 356                         (filler_t *)inode->i_mapping->a_ops->readpage, file);
 357         if (IS_ERR(page))
 358                 goto out;
 359         wait_on_page_locked(page);
 360         if (!PageUptodate(page) || PageError(page)) {
 361                 put_page(page);
 362                 page = ERR_PTR(-EIO);
 363                 goto out;
 364         }
 365
 366         if (index > end_index) /* we have read beyond EOF */
 367                 *bytes_read = 0;
 368         else if (index == end_index) /* possible short read */
 369                 *bytes_read = isize & ~PAGE_MASK;
 370         else
 371                 *bytes_read = PAGE_SIZE; /* got a full page */
 372 out:
 373         if (IS_ERR(page))
 374                 printk(KERN_ALERT "md: bitmap read error: (%dB @ %Lu): %ld\n",
 375                         (int)PAGE_SIZE,
 376                         (unsigned long long)index << PAGE_SHIFT,
 377                         PTR_ERR(page));
 378         return page;
 379 }
 380
 381 /*
 382  * bitmap file superblock operations
 383  */
 384
 385 /* update the event counter and sync the superblock to disk */
 386 int bitmap_update_sb(struct bitmap *bitmap)
 387 {
 388         bitmap_super_t *sb;
 389         unsigned long flags;
 390
 391         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
 392                 return 0;
 393         spin_lock_irqsave(&bitmap->lock, flags);
 394         if (!bitmap->sb_page) { /* no superblock */
 395                 spin_unlock_irqrestore(&bitmap->lock, flags);
 396                 return 0;
 397         }
 398         spin_unlock_irqrestore(&bitmap->lock, flags);
 399         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
 400         sb->events = cpu_to_le64(bitmap->mddev->events);
 401         if (!bitmap->mddev->degraded)
 402                 sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
 403         kunmap_atomic(sb, KM_USER0);
 404         return write_page(bitmap, bitmap->sb_page, 1);
 405 }
 406
 407 /* print out the bitmap file superblock */
 408 void bitmap_print_sb(struct bitmap *bitmap)
 409 {
 410         bitmap_super_t *sb;
 411
 412         if (!bitmap || !bitmap->sb_page)
 413                 return;
 414         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
 415         printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
 416         printk(KERN_DEBUG "         magic: %08x\n", le32_to_cpu(sb->magic));
 417         printk(KERN_DEBUG "       version: %d\n", le32_to_cpu(sb->version));
 418         printk(KERN_DEBUG "          uuid: %08x.%08x.%08x.%08x\n",
 419                                         *(__u32 *)(sb->uuid+0),
 420                                         *(__u32 *)(sb->uuid+4),
 421                                         *(__u32 *)(sb->uuid+8),
 422                                         *(__u32 *)(sb->uuid+12));
 423         printk(KERN_DEBUG "        events: %llu\n",
 424                         (unsigned long long) le64_to_cpu(sb->events));
 425         printk(KERN_DEBUG "events cleared: %llu\n",
 426                         (unsigned long long) le64_to_cpu(sb->events_cleared));
 427         printk(KERN_DEBUG "         state: %08x\n", le32_to_cpu(sb->state));
 428         printk(KERN_DEBUG "     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
 429         printk(KERN_DEBUG "  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
 430         printk(KERN_DEBUG "     sync size: %llu KB\n",
 431                         (unsigned long long)le64_to_cpu(sb->sync_size)/2);
 432         printk(KERN_DEBUG "max write behind: %d\n", le32_to_cpu(sb->write_behind));
 433         kunmap_atomic(sb, KM_USER0);
 434 }
 435
 436 /* read the superblock from the bitmap file and initialize some bitmap fields */
 437 static int bitmap_read_sb(struct bitmap *bitmap)
 438 {
 439         char *reason = NULL;
 440         bitmap_super_t *sb;
 441         unsigned long chunksize, daemon_sleep, write_behind;
 442         unsigned long bytes_read;
 443         unsigned long long events;
 444         int err = -EINVAL;
 445
 446         /* page 0 is the superblock, read it... */
 447         if (bitmap->file)
 448                 bitmap->sb_page = read_page(bitmap->file, 0, &bytes_read);
 449         else {
 450                 bitmap->sb_page = read_sb_page(bitmap->mddev, bitmap->offset, 0);
 451                 bytes_read = PAGE_SIZE;
 452         }
 453         if (IS_ERR(bitmap->sb_page)) {
 454                 err = PTR_ERR(bitmap->sb_page);
 455                 bitmap->sb_page = NULL;
 456                 return err;
 457         }
 458
 459         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
 460
 461         if (bytes_read < sizeof(*sb)) { /* short read */
 462                 printk(KERN_INFO "%s: bitmap file superblock truncated\n",
 463                         bmname(bitmap));
 464                 err = -ENOSPC;
 465                 goto out;
 466         }
 467
 468         chunksize = le32_to_cpu(sb->chunksize);
 469         daemon_sleep = le32_to_cpu(sb->daemon_sleep);
 470         write_behind = le32_to_cpu(sb->write_behind);
 471
 472         /* verify that the bitmap-specific fields are valid */
 473         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
 474                 reason = "bad magic";
 475         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
 476                  le32_to_cpu(sb->version) > BITMAP_MAJOR_HI)
 477                 reason = "unrecognized superblock version";
 478         else if (chunksize < PAGE_SIZE)
 479                 reason = "bitmap chunksize too small";
 480         else if ((1 << ffz(~chunksize)) != chunksize)
 481                 reason = "bitmap chunksize not a power of 2";
 482         else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT / HZ)
 483                 reason = "daemon sleep period out of range";
 484         else if (write_behind > COUNTER_MAX)
 485                 reason = "write-behind limit out of range (0 - 16383)";
 486         if (reason) {
 487                 printk(KERN_INFO "%s: invalid bitmap file superblock: %s\n",
 488                         bmname(bitmap), reason);
 489                 goto out;
 490         }
 491
 492         /* keep the array size field of the bitmap superblock up to date */
 493         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 494
 495         if (!bitmap->mddev->persistent)
 496                 goto success;
 497
 498         /*
 499          * if we have a persistent array superblock, compare the
 500          * bitmap's UUID and event counter to the mddev's
 501          */
 502         if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
 503                 printk(KERN_INFO "%s: bitmap superblock UUID mismatch\n",
 504                         bmname(bitmap));
 505                 goto out;
 506         }
 507         events = le64_to_cpu(sb->events);
 508         if (events < bitmap->mddev->events) {
 509                 printk(KERN_INFO "%s: bitmap file is out of date (%llu < %llu) "
 510                         "-- forcing full recovery\n", bmname(bitmap), events,
 511                         (unsigned long long) bitmap->mddev->events);
 512                 sb->state |= BITMAP_STALE;
 513         }
 514 success:
 515         /* assign fields using values from superblock */
 516         bitmap->chunksize = chunksize;
 517         bitmap->daemon_sleep = daemon_sleep;
 518         bitmap->daemon_lastrun = jiffies;
 519         bitmap->max_write_behind = write_behind;
 520         bitmap->flags |= sb->state;
 521         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
 522                 bitmap->flags |= BITMAP_HOSTENDIAN;
 523         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
 524         if (sb->state & BITMAP_STALE)
 525                 bitmap->events_cleared = bitmap->mddev->events;
 526         err = 0;
 527 out:
 528         kunmap_atomic(sb, KM_USER0);
 529         if (err)
 530                 bitmap_print_sb(bitmap);
 531         return err;
 532 }
 533
 534 enum bitmap_mask_op {
 535         MASK_SET,
 536         MASK_UNSET
 537 };
 538
 539 /* record the state of the bitmap in the superblock */
 540 static void bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
 541                                 enum bitmap_mask_op op)
 542 {
 543         bitmap_super_t *sb;
 544         unsigned long flags;
 545
 546         spin_lock_irqsave(&bitmap->lock, flags);
 547         if (!bitmap->sb_page) { /* can't set the state */
 548                 spin_unlock_irqrestore(&bitmap->lock, flags);
 549                 return;
 550         }
 551         get_page(bitmap->sb_page);
 552         spin_unlock_irqrestore(&bitmap->lock, flags);
 553         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
 554         switch (op) {
 555                 case MASK_SET: sb->state |= bits;
 556                                 break;
 557                 case MASK_UNSET: sb->state &= ~bits;
 558                                 break;
 559                 default: BUG();
 560         }
 561         kunmap_atomic(sb, KM_USER0);
 562         put_page(bitmap->sb_page);
 563 }
 564
 565 /*
 566  * general bitmap file operations
 567  */
 568
 569 /* calculate the index of the page that contains this bit */
 570 static inline unsigned long file_page_index(unsigned long chunk)
 571 {
 572         return CHUNK_BIT_OFFSET(chunk) >> PAGE_BIT_SHIFT;
 573 }
 574
 575 /* calculate the (bit) offset of this bit within a page */
 576 static inline unsigned long file_page_offset(unsigned long chunk)
 577 {
 578         return CHUNK_BIT_OFFSET(chunk) & (PAGE_BITS - 1);
 579 }
 580
 581 /*
 582  * return a pointer to the page in the filemap that contains the given bit
 583  *
 584  * this lookup is complicated by the fact that the bitmap sb might be exactly
 585  * 1 page (e.g., x86) or less than 1 page -- so the bitmap might start on page
 586  * 0 or page 1
 587  */
 588 static inline struct page *filemap_get_page(struct bitmap *bitmap,
 589                                         unsigned long chunk)
 590 {
 591         return bitmap->filemap[file_page_index(chunk) - file_page_index(0)];
 592 }
 593
 594
 595 static void bitmap_file_unmap(struct bitmap *bitmap)
 596 {
 597         struct page **map, *sb_page;
 598         unsigned long *attr;
 599         int pages;
 600         unsigned long flags;
 601
 602         spin_lock_irqsave(&bitmap->lock, flags);
 603         map = bitmap->filemap;
 604         bitmap->filemap = NULL;
 605         attr = bitmap->filemap_attr;
 606         bitmap->filemap_attr = NULL;
 607         pages = bitmap->file_pages;
 608         bitmap->file_pages = 0;
 609         sb_page = bitmap->sb_page;
 610         bitmap->sb_page = NULL;
 611         spin_unlock_irqrestore(&bitmap->lock, flags);
 612
 613         while (pages--)
 614                 if (map[pages]->index != 0) /* 0 is sb_page, release it below */
 615                         put_page(map[pages]);
 616         kfree(map);
 617         kfree(attr);
 618
 619         safe_put_page(sb_page);
 620 }
 621
 622 /* dequeue the next item in a page list -- don't call from irq context */
 623 static struct page_list *dequeue_page(struct bitmap *bitmap)
 624 {
 625         struct page_list *item = NULL;
 626         struct list_head *head = &bitmap->complete_pages;
 627
 628         spin_lock(&bitmap->write_lock);
 629         if (list_empty(head))
 630                 goto out;
 631         item = list_entry(head->prev, struct page_list, list);
 632         list_del(head->prev);
 633 out:
 634         spin_unlock(&bitmap->write_lock);
 635         return item;
 636 }
 637
 638 static void drain_write_queues(struct bitmap *bitmap)
 639 {
 640         struct page_list *item;
 641
 642         while ((item = dequeue_page(bitmap))) {
 643                 /* don't bother to wait */
 644                 put_page(item->page);
 645                 mempool_free(item, bitmap->write_pool);
 646         }
 647 }
 648
 649 static void bitmap_file_put(struct bitmap *bitmap)
 650 {
 651         struct file *file;
 652         struct inode *inode;
 653         unsigned long flags;
 654
 655         spin_lock_irqsave(&bitmap->lock, flags);
 656         file = bitmap->file;
 657         bitmap->file = NULL;
 658         spin_unlock_irqrestore(&bitmap->lock, flags);
 659
 660         drain_write_queues(bitmap);
 661
 662         bitmap_file_unmap(bitmap);
 663
 664         if (file) {
 665                 inode = file->f_mapping->host;
 666                 spin_lock(&inode->i_lock);
 667                 atomic_set(&inode->i_writecount, 1); /* allow writes again */
 668                 spin_unlock(&inode->i_lock);
 669                 fput(file);
 670         }
 671 }
 672
 673
 674 /*
 675  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
 676  * then it is no longer reliable, so we stop using it and we mark the file
 677  * as failed in the superblock
 678  */
 679 static void bitmap_file_kick(struct bitmap *bitmap)
 680 {
 681         char *path, *ptr = NULL;
 682
 683         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET);
 684         bitmap_update_sb(bitmap);
 685
 686         if (bitmap->file) {
 687                 path = kmalloc(PAGE_SIZE, GFP_KERNEL);
 688                 if (path)
 689                         ptr = file_path(bitmap->file, path, PAGE_SIZE);
 690
 691                 printk(KERN_ALERT "%s: kicking failed bitmap file %s from array!\n",
 692                        bmname(bitmap), ptr ? ptr : "");
 693
 694                 kfree(path);
 695         }
 696
 697         bitmap_file_put(bitmap);
 698
 699         return;
 700 }
 701
 702 enum bitmap_page_attr {
 703         BITMAP_PAGE_DIRTY = 0, // there are set bits that need to be synced
 704         BITMAP_PAGE_CLEAN = 1, // there are bits that might need to be cleared
 705         BITMAP_PAGE_NEEDWRITE=2, // there are cleared bits that need to be synced
 706 };
 707
 708 static inline void set_page_attr(struct bitmap *bitmap, struct page *page,
 709                                 enum bitmap_page_attr attr)
 710 {
 711         __set_bit((page->index<<2) + attr, bitmap->filemap_attr);
 712 }
 713
 714 static inline void clear_page_attr(struct bitmap *bitmap, struct page *page,
 715                                 enum bitmap_page_attr attr)
 716 {
 717         __clear_bit((page->index<<2) + attr, bitmap->filemap_attr);
 718 }
 719
 720 static inline unsigned long test_page_attr(struct bitmap *bitmap, struct page *page,
 721                                            enum bitmap_page_attr attr)
 722 {
 723         return test_bit((page->index<<2) + attr, bitmap->filemap_attr);
 724 }
 725
 726 /*
 727  * bitmap_file_set_bit -- called before performing a write to the md device
 728  * to set (and eventually sync) a particular bit in the bitmap file
 729  *
 730  * we set the bit immediately, then we record the page number so that
 731  * when an unplug occurs, we can flush the dirty pages out to disk
 732  */
 733 static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 734 {
 735         unsigned long bit;
 736         struct page *page;
 737         void *kaddr;
 738         unsigned long chunk = block >> CHUNK_BLOCK_SHIFT(bitmap);
 739
 740         if (!bitmap->filemap) {
 741                 return;
 742         }
 743
 744         page = filemap_get_page(bitmap, chunk);
 745         bit = file_page_offset(chunk);
 746
 747
 748         /* make sure the page stays cached until it gets written out */
 749         if (! test_page_attr(bitmap, page, BITMAP_PAGE_DIRTY))
 750                 get_page(page);
 751
 752         /* set the bit */
 753         kaddr = kmap_atomic(page, KM_USER0);
 754         if (bitmap->flags & BITMAP_HOSTENDIAN)
 755                 set_bit(bit, kaddr);
 756         else
 757                 ext2_set_bit(bit, kaddr);
 758         kunmap_atomic(kaddr, KM_USER0);
 759         PRINTK("set file bit %lu page %lu\n", bit, page->index);
 760
 761         /* record page number so it gets flushed to disk when unplug occurs */
 762         set_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 763
 764 }
 765
 766 static void bitmap_writeback(struct bitmap *bitmap);
 767
 768 /* this gets called when the md device is ready to unplug its underlying
 769  * (slave) device queues -- before we let any writes go down, we need to
 770  * sync the dirty pages of the bitmap file to disk */
 771 int bitmap_unplug(struct bitmap *bitmap)
 772 {
 773         unsigned long i, flags;
 774         int dirty, need_write;
 775         struct page *page;
 776         int wait = 0;
 777         int err;
 778
 779         if (!bitmap)
 780                 return 0;
 781
 782         /* look at each page to see if there are any set bits that need to be
 783          * flushed out to disk */
 784         for (i = 0; i < bitmap->file_pages; i++) {
 785                 spin_lock_irqsave(&bitmap->lock, flags);
 786                 if (!bitmap->filemap) {
 787                         spin_unlock_irqrestore(&bitmap->lock, flags);
 788                         return 0;
 789                 }
 790                 page = bitmap->filemap[i];
 791                 dirty = test_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 792                 need_write = test_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 793                 clear_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 794                 clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 795                 if (dirty)
 796                         wait = 1;
 797                 spin_unlock_irqrestore(&bitmap->lock, flags);
 798
 799                 if (dirty | need_write) {
 800                         err = write_page(bitmap, page, 0);
 801                         if (err == -EAGAIN) {
 802                                 if (dirty)
 803                                         err = write_page(bitmap, page, 1);
 804                                 else
 805                                         err = 0;
 806                         }
 807                         if (err)
 808                                 return 1;
 809                 }
 810         }
 811         if (wait) { /* if any writes were performed, we need to wait on them */
 812                 if (bitmap->file)
 813                         bitmap_writeback(bitmap);
 814                 else
 815                         md_super_wait(bitmap->mddev);
 816         }
 817         return 0;
 818 }
 819
 820 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
 821 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
 822  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
 823  * memory mapping of the bitmap file
 824  * Special cases:
 825  *   if there's no bitmap file, or if the bitmap file had been
 826  *   previously kicked from the array, we mark all the bits as
 827  *   1's in order to cause a full resync.
 828  *
 829  * We ignore all bits for sectors that end earlier than 'start'.
 830  * This is used when reading an out-of-date bitmap...
 831  */
 832 static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
 833 {
 834         unsigned long i, chunks, index, oldindex, bit;
 835         struct page *page = NULL, *oldpage = NULL;
 836         unsigned long num_pages, bit_cnt = 0;
 837         struct file *file;
 838         unsigned long bytes, offset, dummy;
 839         int outofdate;
 840         int ret = -ENOSPC;
 841         void *paddr;
 842
 843         chunks = bitmap->chunks;
 844         file = bitmap->file;
 845
 846         BUG_ON(!file && !bitmap->offset);
 847
 848 #ifdef INJECT_FAULTS_3
 849         outofdate = 1;
 850 #else
 851         outofdate = bitmap->flags & BITMAP_STALE;
 852 #endif
 853         if (outofdate)
 854                 printk(KERN_INFO "%s: bitmap file is out of date, doing full "
 855                         "recovery\n", bmname(bitmap));
 856
 857         bytes = (chunks + 7) / 8;
 858
 859         num_pages = (bytes + sizeof(bitmap_super_t) + PAGE_SIZE - 1) / PAGE_SIZE;
 860
 861         if (file && i_size_read(file->f_mapping->host) < bytes + sizeof(bitmap_super_t)) {
 862                 printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
 863                         bmname(bitmap),
 864                         (unsigned long) i_size_read(file->f_mapping->host),
 865                         bytes + sizeof(bitmap_super_t));
 866                 goto out;
 867         }
 868
 869         ret = -ENOMEM;
 870
 871         bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
 872         if (!bitmap->filemap)
 873                 goto out;
 874
 875         /* We need 4 bits per page, rounded up to a multiple of sizeof(unsigned long) */
 876         bitmap->filemap_attr = kzalloc(
 877                 (((num_pages*4/8)+sizeof(unsigned long)-1)
 878                  /sizeof(unsigned long))
 879                 *sizeof(unsigned long),
 880                 GFP_KERNEL);
 881         if (!bitmap->filemap_attr)
 882                 goto out;
 883
 884         oldindex = ~0L;
 885
 886         for (i = 0; i < chunks; i++) {
 887                 int b;
 888                 index = file_page_index(i);
 889                 bit = file_page_offset(i);
 890                 if (index != oldindex) { /* this is a new page, read it in */
 891                         /* unmap the old page, we're done with it */
 892                         if (index == 0) {
 893                                 /*
 894                                  * if we're here then the superblock page
 895                                  * contains some bits (PAGE_SIZE != sizeof sb)
 896                                  * we've already read it in, so just use it
 897                                  */
 898                                 page = bitmap->sb_page;
 899                                 offset = sizeof(bitmap_super_t);
 900                         } else if (file) {
 901                                 page = read_page(file, index, &dummy);
 902                                 offset = 0;
 903                         } else {
 904                                 page = read_sb_page(bitmap->mddev, bitmap->offset, index);
 905                                 offset = 0;
 906                         }
 907                         if (IS_ERR(page)) { /* read error */
 908                                 ret = PTR_ERR(page);
 909                                 goto out;
 910                         }
 911
 912                         oldindex = index;
 913                         oldpage = page;
 914
 915                         if (outofdate) {
 916                                 /*
 917                                  * if bitmap is out of date, dirty the
 918                                  * whole page and write it out
 919                                  */
 920                                 paddr = kmap_atomic(page, KM_USER0);
 921                                 memset(paddr + offset, 0xff,
 922                                        PAGE_SIZE - offset);
 923                                 kunmap_atomic(paddr, KM_USER0);
 924                                 ret = write_page(bitmap, page, 1);
 925                                 if (ret) {
 926                                         /* release, page not in filemap yet */
 927                                         put_page(page);
 928                                         goto out;
 929                                 }
 930                         }
 931
 932                         bitmap->filemap[bitmap->file_pages++] = page;
 933                 }
 934                 paddr = kmap_atomic(page, KM_USER0);
 935                 if (bitmap->flags & BITMAP_HOSTENDIAN)
 936                         b = test_bit(bit, paddr);
 937                 else
 938                         b = ext2_test_bit(bit, paddr);
 939                 kunmap_atomic(paddr, KM_USER0);
 940                 if (b) {
 941                         /* if the disk bit is set, set the memory bit */
 942                         bitmap_set_memory_bits(bitmap, i << CHUNK_BLOCK_SHIFT(bitmap),
 943                                                ((i+1) << (CHUNK_BLOCK_SHIFT(bitmap)) >= start)
 944                                 );
 945                         bit_cnt++;
 946                         set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
 947                 }
 948         }
 949
 950         /* everything went OK */
 951         ret = 0;
 952         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_UNSET);
 953
 954         if (bit_cnt) { /* Kick recovery if any bits were set */
 955                 set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
 956                 md_wakeup_thread(bitmap->mddev->thread);
 957         }
 958
 959 out:
 960         printk(KERN_INFO "%s: bitmap initialized from disk: "
 961                 "read %lu/%lu pages, set %lu bits, status: %d\n",
 962                 bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt, ret);
 963
 964         return ret;
 965 }
 966
 967 void bitmap_write_all(struct bitmap *bitmap)
 968 {
 969         /* We don't actually write all bitmap blocks here,
 970          * just flag them as needing to be written
 971          */
 972         int i;
 973
 974         for (i=0; i < bitmap->file_pages; i++)
 975                 set_page_attr(bitmap, bitmap->filemap[i],
 976                               BITMAP_PAGE_NEEDWRITE);
 977 }
 978
 979
 980 static void bitmap_count_page(struct bitmap *bitmap, sector_t offset, int inc)
 981 {
 982         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
 983         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
 984         bitmap->bp[page].count += inc;
 985 /*
 986         if (page == 0) printk("count page 0, offset %llu: %d gives %d\n",
 987                               (unsigned long long)offset, inc, bitmap->bp[page].count);
 988 */
 989         bitmap_checkfree(bitmap, page);
 990 }
 991 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
 992                                             sector_t offset, int *blocks,
 993                                             int create);
 994
 995 /*
 996  * bitmap daemon -- periodically wakes up to clean bits and flush pages
 997  *                      out to disk
 998  */
 999
1000 int bitmap_daemon_work(struct bitmap *bitmap)
1001 {
1002         unsigned long j;
1003         unsigned long flags;
1004         struct page *page = NULL, *lastpage = NULL;
1005         int err = 0;
1006         int blocks;
1007         void *paddr;
1008
1009         if (bitmap == NULL)
1010                 return 0;
1011         if (time_before(jiffies, bitmap->daemon_lastrun + bitmap->daemon_sleep*HZ))
1012                 return 0;
1013         bitmap->daemon_lastrun = jiffies;
1014
1015         for (j = 0; j < bitmap->chunks; j++) {
1016                 bitmap_counter_t *bmc;
1017                 spin_lock_irqsave(&bitmap->lock, flags);
1018                 if (!bitmap->filemap) {
1019                         /* error or shutdown */
1020                         spin_unlock_irqrestore(&bitmap->lock, flags);
1021                         break;
1022                 }
1023
1024                 page = filemap_get_page(bitmap, j);
1025
1026                 if (page != lastpage) {
1027                         /* skip this page unless it's marked as needing cleaning */
1028                         if (!test_page_attr(bitmap, page, BITMAP_PAGE_CLEAN)) {
1029                                 int need_write = test_page_attr(bitmap, page,
1030                                                                 BITMAP_PAGE_NEEDWRITE);
1031                                 if (need_write) {
1032                                         get_page(page);
1033                                         clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
1034                                 }
1035                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1036                                 if (need_write) {
1037                                         switch (write_page(bitmap, page, 0)) {
1038                                         case -EAGAIN:
1039                                                 set_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
1040                                                 break;
1041                                         case 0:
1042                                                 break;
1043                                         default:
1044                                                 bitmap_file_kick(bitmap);
1045                                         }
1046                                         put_page(page);
1047                                 }
1048                                 continue;
1049                         }
1050
1051                         /* grab the new page, sync and release the old */
1052                         get_page(page);
1053                         if (lastpage != NULL) {
1054                                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1055                                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1056                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1057                                         err = write_page(bitmap, lastpage, 0);
1058                                         if (err == -EAGAIN) {
1059                                                 err = 0;
1060                                                 set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1061                                         }
1062                                 } else {
1063                                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1064                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1065                                 }
1066                                 put_page(lastpage);
1067                                 if (err)
1068                                         bitmap_file_kick(bitmap);
1069                         } else
1070                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1071                         lastpage = page;
1072 /*
1073                         printk("bitmap clean at page %lu\n", j);
1074 */
1075                         spin_lock_irqsave(&bitmap->lock, flags);
1076                         clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1077                 }
1078                 bmc = bitmap_get_counter(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
1079                                         &blocks, 0);
1080                 if (bmc) {
1081 /*
1082   if (j < 100) printk("bitmap: j=%lu, *bmc = 0x%x\n", j, *bmc);
1083 */
1084                         if (*bmc == 2) {
1085                                 *bmc=1; /* maybe clear the bit next time */
1086                                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1087                         } else if (*bmc == 1) {
1088                                 /* we can clear the bit */
1089                                 *bmc = 0;
1090                                 bitmap_count_page(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
1091                                                   -1);
1092
1093                                 /* clear the bit */
1094                                 paddr = kmap_atomic(page, KM_USER0);
1095                                 if (bitmap->flags & BITMAP_HOSTENDIAN)
1096                                         clear_bit(file_page_offset(j), paddr);
1097                                 else
1098                                         ext2_clear_bit(file_page_offset(j), paddr);
1099                                 kunmap_atomic(paddr, KM_USER0);
1100                         }
1101                 }
1102                 spin_unlock_irqrestore(&bitmap->lock, flags);
1103         }
1104
1105         /* now sync the final page */
1106         if (lastpage != NULL) {
1107                 spin_lock_irqsave(&bitmap->lock, flags);
1108                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1109                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1110                         spin_unlock_irqrestore(&bitmap->lock, flags);
1111                         err = write_page(bitmap, lastpage, 0);
1112                         if (err == -EAGAIN) {
1113                                 set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1114                                 err = 0;
1115                         }
1116                 } else {
1117                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1118                         spin_unlock_irqrestore(&bitmap->lock, flags);
1119                 }
1120
1121                 put_page(lastpage);
1122         }
1123
1124         return err;
1125 }
1126
1127 static void bitmap_writeback(struct bitmap *bitmap)
1128 {
1129         struct page *page;
1130         struct page_list *item;
1131         int err = 0;
1132
1133         PRINTK("%s: bitmap writeback daemon woke up...\n", bmname(bitmap));
1134         /* wait on bitmap page writebacks */
1135         while ((item = dequeue_page(bitmap))) {
1136                 page = item->page;
1137                 mempool_free(item, bitmap->write_pool);
1138                 PRINTK("wait on page writeback: %p\n", page);
1139                 wait_on_page_writeback(page);
1140                 PRINTK("finished page writeback: %p\n", page);
1141
1142                 err = PageError(page);
1143                 put_page(page);
1144                 if (err) {
1145                         printk(KERN_WARNING "%s: bitmap file writeback "
1146                                "failed (page %lu): %d\n",
1147                                bmname(bitmap), page->index, err);
1148                         bitmap_file_kick(bitmap);
1149                         break;
1150                 }
1151         }
1152 }
1153
1154 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1155                                             sector_t offset, int *blocks,
1156                                             int create)
1157 {
1158         /* If 'create', we might release the lock and reclaim it.
1159          * The lock must have been taken with interrupts enabled.
1160          * If !create, we don't release the lock.
1161          */
1162         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1163         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1164         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1165         sector_t csize;
1166
1167         if (bitmap_checkpage(bitmap, page, create) < 0) {
1168                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1169                 *blocks = csize - (offset & (csize- 1));
1170                 return NULL;
1171         }
1172         /* now locked ... */
1173
1174         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1175                 /* should we use the first or second counter field
1176                  * of the hijacked pointer? */
1177                 int hi = (pageoff > PAGE_COUNTER_MASK);
1178                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap) +
1179                                           PAGE_COUNTER_SHIFT - 1);
1180                 *blocks = csize - (offset & (csize- 1));
1181                 return  &((bitmap_counter_t *)
1182                           &bitmap->bp[page].map)[hi];
1183         } else { /* page is allocated */
1184                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1185                 *blocks = csize - (offset & (csize- 1));
1186                 return (bitmap_counter_t *)
1187                         &(bitmap->bp[page].map[pageoff]);
1188         }
1189 }
1190
1191 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1192 {
1193         if (!bitmap) return 0;
1194
1195         if (behind) {
1196                 atomic_inc(&bitmap->behind_writes);
1197                 PRINTK(KERN_DEBUG "inc write-behind count %d/%d\n",
1198                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1199         }
1200
1201         while (sectors) {
1202                 int blocks;
1203                 bitmap_counter_t *bmc;
1204
1205                 spin_lock_irq(&bitmap->lock);
1206                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 1);
1207                 if (!bmc) {
1208                         spin_unlock_irq(&bitmap->lock);
1209                         return 0;
1210                 }
1211
1212                 switch(*bmc) {
1213                 case 0:
1214                         bitmap_file_set_bit(bitmap, offset);
1215                         bitmap_count_page(bitmap,offset, 1);
1216                         blk_plug_device(bitmap->mddev->queue);
1217                         /* fall through */
1218                 case 1:
1219                         *bmc = 2;
1220                 }
1221                 BUG_ON((*bmc & COUNTER_MAX) == COUNTER_MAX);
1222                 (*bmc)++;
1223
1224                 spin_unlock_irq(&bitmap->lock);
1225
1226                 offset += blocks;
1227                 if (sectors > blocks)
1228                         sectors -= blocks;
1229                 else sectors = 0;
1230         }
1231         return 0;
1232 }
1233
1234 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1235                      int success, int behind)
1236 {
1237         if (!bitmap) return;
1238         if (behind) {
1239                 atomic_dec(&bitmap->behind_writes);
1240                 PRINTK(KERN_DEBUG "dec write-behind count %d/%d\n",
1241                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1242         }
1243
1244         while (sectors) {
1245                 int blocks;
1246                 unsigned long flags;
1247                 bitmap_counter_t *bmc;
1248
1249                 spin_lock_irqsave(&bitmap->lock, flags);
1250                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 0);
1251                 if (!bmc) {
1252                         spin_unlock_irqrestore(&bitmap->lock, flags);
1253                         return;
1254                 }
1255
1256                 if (!success && ! (*bmc & NEEDED_MASK))
1257                         *bmc |= NEEDED_MASK;
1258
1259                 (*bmc)--;
1260                 if (*bmc <= 2) {
1261                         set_page_attr(bitmap,
1262                                       filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1263                                       BITMAP_PAGE_CLEAN);
1264                 }
1265                 spin_unlock_irqrestore(&bitmap->lock, flags);
1266                 offset += blocks;
1267                 if (sectors > blocks)
1268                         sectors -= blocks;
1269                 else sectors = 0;
1270         }
1271 }
1272
1273 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
1274                         int degraded)
1275 {
1276         bitmap_counter_t *bmc;
1277         int rv;
1278         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1279                 *blocks = 1024;
1280                 return 1; /* always resync if no bitmap */
1281         }
1282         spin_lock_irq(&bitmap->lock);
1283         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1284         rv = 0;
1285         if (bmc) {
1286                 /* locked */
1287                 if (RESYNC(*bmc))
1288                         rv = 1;
1289                 else if (NEEDED(*bmc)) {
1290                         rv = 1;
1291                         if (!degraded) { /* don't set/clear bits if degraded */
1292                                 *bmc |= RESYNC_MASK;
1293                                 *bmc &= ~NEEDED_MASK;
1294                         }
1295                 }
1296         }
1297         spin_unlock_irq(&bitmap->lock);
1298         return rv;
1299 }
1300
1301 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int aborted)
1302 {
1303         bitmap_counter_t *bmc;
1304         unsigned long flags;
1305 /*
1306         if (offset == 0) printk("bitmap_end_sync 0 (%d)\n", aborted);
1307 */      if (bitmap == NULL) {
1308                 *blocks = 1024;
1309                 return;
1310         }
1311         spin_lock_irqsave(&bitmap->lock, flags);
1312         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1313         if (bmc == NULL)
1314                 goto unlock;
1315         /* locked */
1316 /*
1317         if (offset == 0) printk("bitmap_end sync found 0x%x, blocks %d\n", *bmc, *blocks);
1318 */
1319         if (RESYNC(*bmc)) {
1320                 *bmc &= ~RESYNC_MASK;
1321
1322                 if (!NEEDED(*bmc) && aborted)
1323                         *bmc |= NEEDED_MASK;
1324                 else {
1325                         if (*bmc <= 2) {
1326                                 set_page_attr(bitmap,
1327                                               filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1328                                               BITMAP_PAGE_CLEAN);
1329                         }
1330                 }
1331         }
1332  unlock:
1333         spin_unlock_irqrestore(&bitmap->lock, flags);
1334 }
1335
1336 void bitmap_close_sync(struct bitmap *bitmap)
1337 {
1338         /* Sync has finished, and any bitmap chunks that weren't synced
1339          * properly have been aborted.  It remains to us to clear the
1340          * RESYNC bit wherever it is still on
1341          */
1342         sector_t sector = 0;
1343         int blocks;
1344         if (!bitmap) return;
1345         while (sector < bitmap->mddev->resync_max_sectors) {
1346                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1347 /*
1348                 if (sector < 500) printk("bitmap_close_sync: sec %llu blks %d\n",
1349                                          (unsigned long long)sector, blocks);
1350 */              sector += blocks;
1351         }
1352 }
1353
1354 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1355 {
1356         /* For each chunk covered by any of these sectors, set the
1357          * counter to 1 and set resync_needed.  They should all
1358          * be 0 at this point
1359          */
1360
1361         int secs;
1362         bitmap_counter_t *bmc;
1363         spin_lock_irq(&bitmap->lock);
1364         bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
1365         if (!bmc) {
1366                 spin_unlock_irq(&bitmap->lock);
1367                 return;
1368         }
1369         if (! *bmc) {
1370                 struct page *page;
1371                 *bmc = 1 | (needed?NEEDED_MASK:0);
1372                 bitmap_count_page(bitmap, offset, 1);
1373                 page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));
1374                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1375         }
1376         spin_unlock_irq(&bitmap->lock);
1377
1378 }
1379
1380 /*
1381  * flush out any pending updates
1382  */
1383 void bitmap_flush(mddev_t *mddev)
1384 {
1385         struct bitmap *bitmap = mddev->bitmap;
1386         int sleep;
1387
1388         if (!bitmap) /* there was no bitmap */
1389                 return;
1390
1391         /* run the daemon_work three time to ensure everything is flushed
1392          * that can be
1393          */
1394         sleep = bitmap->daemon_sleep;
1395         bitmap->daemon_sleep = 0;
1396         bitmap_daemon_work(bitmap);
1397         bitmap_daemon_work(bitmap);
1398         bitmap_daemon_work(bitmap);
1399         bitmap->daemon_sleep = sleep;
1400         bitmap_update_sb(bitmap);
1401 }
1402
1403 /*
1404  * free memory that was allocated
1405  */
1406 static void bitmap_free(struct bitmap *bitmap)
1407 {
1408         unsigned long k, pages;
1409         struct bitmap_page *bp;
1410
1411         if (!bitmap) /* there was no bitmap */
1412                 return;
1413
1414         /* release the bitmap file and kill the daemon */
1415         bitmap_file_put(bitmap);
1416
1417         bp = bitmap->bp;
1418         pages = bitmap->pages;
1419
1420         /* free all allocated memory */
1421
1422         mempool_destroy(bitmap->write_pool);
1423
1424         if (bp) /* deallocate the page memory */
1425                 for (k = 0; k < pages; k++)
1426                         if (bp[k].map && !bp[k].hijacked)
1427                                 kfree(bp[k].map);
1428         kfree(bp);
1429         kfree(bitmap);
1430 }
1431 void bitmap_destroy(mddev_t *mddev)
1432 {
1433         struct bitmap *bitmap = mddev->bitmap;
1434
1435         if (!bitmap) /* there was no bitmap */
1436                 return;
1437
1438         mddev->bitmap = NULL; /* disconnect from the md device */
1439         if (mddev->thread)
1440                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1441
1442         bitmap_free(bitmap);
1443 }
1444
1445 /*
1446  * initialize the bitmap structure
1447  * if this returns an error, bitmap_destroy must be called to do clean up
1448  */
1449 int bitmap_create(mddev_t *mddev)
1450 {
1451         struct bitmap *bitmap;
1452         unsigned long blocks = mddev->resync_max_sectors;
1453         unsigned long chunks;
1454         unsigned long pages;
1455         struct file *file = mddev->bitmap_file;
1456         int err;
1457         sector_t start;
1458
1459         BUG_ON(sizeof(bitmap_super_t) != 256);
1460
1461         if (!file && !mddev->bitmap_offset) /* bitmap disabled, nothing to do */
1462                 return 0;
1463
1464         BUG_ON(file && mddev->bitmap_offset);
1465
1466         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1467         if (!bitmap)
1468                 return -ENOMEM;
1469
1470         spin_lock_init(&bitmap->lock);
1471         bitmap->mddev = mddev;
1472
1473         spin_lock_init(&bitmap->write_lock);
1474         INIT_LIST_HEAD(&bitmap->complete_pages);
1475         bitmap->write_pool = mempool_create_kmalloc_pool(WRITE_POOL_SIZE,
1476                                                 sizeof(struct page_list));
1477         err = -ENOMEM;
1478         if (!bitmap->write_pool)
1479                 goto error;
1480
1481         bitmap->file = file;
1482         bitmap->offset = mddev->bitmap_offset;
1483         if (file) get_file(file);
1484         /* read superblock from bitmap file (this sets bitmap->chunksize) */
1485         err = bitmap_read_sb(bitmap);
1486         if (err)
1487                 goto error;
1488
1489         bitmap->chunkshift = find_first_bit(&bitmap->chunksize,
1490                                         sizeof(bitmap->chunksize));
1491
1492         /* now that chunksize and chunkshift are set, we can use these macros */
1493         chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) /
1494                         CHUNK_BLOCK_RATIO(bitmap);
1495         pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
1496
1497         BUG_ON(!pages);
1498
1499         bitmap->chunks = chunks;
1500         bitmap->pages = pages;
1501         bitmap->missing_pages = pages;
1502         bitmap->counter_bits = COUNTER_BITS;
1503
1504         bitmap->syncchunk = ~0UL;
1505
1506 #ifdef INJECT_FATAL_FAULT_1
1507         bitmap->bp = NULL;
1508 #else
1509         bitmap->bp = kzalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
1510 #endif
1511         err = -ENOMEM;
1512         if (!bitmap->bp)
1513                 goto error;
1514
1515         bitmap->flags |= BITMAP_ACTIVE;
1516
1517         /* now that we have some pages available, initialize the in-memory
1518          * bitmap from the on-disk bitmap */
1519         start = 0;
1520         if (mddev->degraded == 0
1521             || bitmap->events_cleared == mddev->events)
1522                 /* no need to keep dirty bits to optimise a re-add of a missing device */
1523                 start = mddev->recovery_cp;
1524         err = bitmap_init_from_disk(bitmap, start);
1525
1526         if (err)
1527                 goto error;
1528
1529         printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
1530                 pages, bmname(bitmap));
1531
1532         mddev->bitmap = bitmap;
1533
1534         mddev->thread->timeout = bitmap->daemon_sleep * HZ;
1535
1536         return bitmap_update_sb(bitmap);
1537
1538  error:
1539         bitmap_free(bitmap);
1540         return err;
1541 }
1542
1543 /* the bitmap API -- for raid personalities */
1544 EXPORT_SYMBOL(bitmap_startwrite);
1545 EXPORT_SYMBOL(bitmap_endwrite);
1546 EXPORT_SYMBOL(bitmap_start_sync);
1547 EXPORT_SYMBOL(bitmap_end_sync);
1548 EXPORT_SYMBOL(bitmap_unplug);
1549 EXPORT_SYMBOL(bitmap_close_sync);
1550 EXPORT_SYMBOL(bitmap_daemon_work);