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 /*
 262  * write out a page
 263  */
 264 static int write_page(struct page *page, int wait)
 265 {
 266         int ret = -ENOMEM;
 267
 268         lock_page(page);
 269
 270         if (page->mapping == NULL)
 271                 goto unlock_out;
 272         else if (i_size_read(page->mapping->host) < page->index << PAGE_SHIFT) {
 273                 ret = -ENOENT;
 274                 goto unlock_out;
 275         }
 276
 277         ret = page->mapping->a_ops->prepare_write(NULL, page, 0, PAGE_SIZE);
 278         if (!ret)
 279                 ret = page->mapping->a_ops->commit_write(NULL, page, 0,
 280                         PAGE_SIZE);
 281         if (ret) {
 282 unlock_out:
 283                 unlock_page(page);
 284                 return ret;
 285         }
 286
 287         set_page_dirty(page); /* force it to be written out */
 288         return write_one_page(page, wait);
 289 }
 290
 291 /* read a page from a file, pinning it into cache, and return bytes_read */
 292 static struct page *read_page(struct file *file, unsigned long index,
 293                                         unsigned long *bytes_read)
 294 {
 295         struct inode *inode = file->f_mapping->host;
 296         struct page *page = NULL;
 297         loff_t isize = i_size_read(inode);
 298         unsigned long end_index = isize >> PAGE_CACHE_SHIFT;
 299
 300         PRINTK("read bitmap file (%dB @ %Lu)\n", (int)PAGE_CACHE_SIZE,
 301                         (unsigned long long)index << PAGE_CACHE_SHIFT);
 302
 303         page = read_cache_page(inode->i_mapping, index,
 304                         (filler_t *)inode->i_mapping->a_ops->readpage, file);
 305         if (IS_ERR(page))
 306                 goto out;
 307         wait_on_page_locked(page);
 308         if (!PageUptodate(page) || PageError(page)) {
 309                 page_cache_release(page);
 310                 page = ERR_PTR(-EIO);
 311                 goto out;
 312         }
 313
 314         if (index > end_index) /* we have read beyond EOF */
 315                 *bytes_read = 0;
 316         else if (index == end_index) /* possible short read */
 317                 *bytes_read = isize & ~PAGE_CACHE_MASK;
 318         else
 319                 *bytes_read = PAGE_CACHE_SIZE; /* got a full page */
 320 out:
 321         if (IS_ERR(page))
 322                 printk(KERN_ALERT "md: bitmap read error: (%dB @ %Lu): %ld\n",
 323                         (int)PAGE_CACHE_SIZE,
 324                         (unsigned long long)index << PAGE_CACHE_SHIFT,
 325                         PTR_ERR(page));
 326         return page;
 327 }
 328
 329 /*
 330  * bitmap file superblock operations
 331  */
 332
 333 /* update the event counter and sync the superblock to disk */
 334 int bitmap_update_sb(struct bitmap *bitmap)
 335 {
 336         bitmap_super_t *sb;
 337         unsigned long flags;
 338
 339         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
 340                 return 0;
 341         spin_lock_irqsave(&bitmap->lock, flags);
 342         if (!bitmap->sb_page) { /* no superblock */
 343                 spin_unlock_irqrestore(&bitmap->lock, flags);
 344                 return 0;
 345         }
 346         page_cache_get(bitmap->sb_page);
 347         spin_unlock_irqrestore(&bitmap->lock, flags);
 348         sb = (bitmap_super_t *)kmap(bitmap->sb_page);
 349         sb->events = cpu_to_le64(bitmap->mddev->events);
 350         if (!bitmap->mddev->degraded)
 351                 sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
 352         kunmap(bitmap->sb_page);
 353         write_page(bitmap->sb_page, 0);
 354         return 0;
 355 }
 356
 357 /* print out the bitmap file superblock */
 358 void bitmap_print_sb(struct bitmap *bitmap)
 359 {
 360         bitmap_super_t *sb;
 361
 362         if (!bitmap || !bitmap->sb_page)
 363                 return;
 364         sb = (bitmap_super_t *)kmap(bitmap->sb_page);
 365         printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
 366         printk(KERN_DEBUG "       magic: %08x\n", le32_to_cpu(sb->magic));
 367         printk(KERN_DEBUG "     version: %d\n", le32_to_cpu(sb->version));
 368         printk(KERN_DEBUG "        uuid: %08x.%08x.%08x.%08x\n",
 369                                         *(__u32 *)(sb->uuid+0),
 370                                         *(__u32 *)(sb->uuid+4),
 371                                         *(__u32 *)(sb->uuid+8),
 372                                         *(__u32 *)(sb->uuid+12));
 373         printk(KERN_DEBUG "      events: %llu\n",
 374                         (unsigned long long) le64_to_cpu(sb->events));
 375         printk(KERN_DEBUG "events_clred: %llu\n",
 376                         (unsigned long long) le64_to_cpu(sb->events_cleared));
 377         printk(KERN_DEBUG "       state: %08x\n", le32_to_cpu(sb->state));
 378         printk(KERN_DEBUG "   chunksize: %d B\n", le32_to_cpu(sb->chunksize));
 379         printk(KERN_DEBUG "daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
 380         printk(KERN_DEBUG "   sync size: %llu KB\n", le64_to_cpu(sb->sync_size));
 381         kunmap(bitmap->sb_page);
 382 }
 383
 384 /* read the superblock from the bitmap file and initialize some bitmap fields */
 385 static int bitmap_read_sb(struct bitmap *bitmap)
 386 {
 387         char *reason = NULL;
 388         bitmap_super_t *sb;
 389         unsigned long chunksize, daemon_sleep;
 390         unsigned long bytes_read;
 391         unsigned long long events;
 392         int err = -EINVAL;
 393
 394         /* page 0 is the superblock, read it... */
 395         bitmap->sb_page = read_page(bitmap->file, 0, &bytes_read);
 396         if (IS_ERR(bitmap->sb_page)) {
 397                 err = PTR_ERR(bitmap->sb_page);
 398                 bitmap->sb_page = NULL;
 399                 return err;
 400         }
 401
 402         sb = (bitmap_super_t *)kmap(bitmap->sb_page);
 403
 404         if (bytes_read < sizeof(*sb)) { /* short read */
 405                 printk(KERN_INFO "%s: bitmap file superblock truncated\n",
 406                         bmname(bitmap));
 407                 err = -ENOSPC;
 408                 goto out;
 409         }
 410
 411         chunksize = le32_to_cpu(sb->chunksize);
 412         daemon_sleep = le32_to_cpu(sb->daemon_sleep);
 413
 414         /* verify that the bitmap-specific fields are valid */
 415         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
 416                 reason = "bad magic";
 417         else if (sb->version != cpu_to_le32(BITMAP_MAJOR))
 418                 reason = "unrecognized superblock version";
 419         else if (chunksize < 512 || chunksize > (1024 * 1024 * 4))
 420                 reason = "bitmap chunksize out of range (512B - 4MB)";
 421         else if ((1 << ffz(~chunksize)) != chunksize)
 422                 reason = "bitmap chunksize not a power of 2";
 423         else if (daemon_sleep < 1 || daemon_sleep > 15)
 424                 reason = "daemon sleep period out of range";
 425         if (reason) {
 426                 printk(KERN_INFO "%s: invalid bitmap file superblock: %s\n",
 427                         bmname(bitmap), reason);
 428                 goto out;
 429         }
 430
 431         /* keep the array size field of the bitmap superblock up to date */
 432         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 433
 434         if (!bitmap->mddev->persistent)
 435                 goto success;
 436
 437         /*
 438          * if we have a persistent array superblock, compare the
 439          * bitmap's UUID and event counter to the mddev's
 440          */
 441         if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
 442                 printk(KERN_INFO "%s: bitmap superblock UUID mismatch\n",
 443                         bmname(bitmap));
 444                 goto out;
 445         }
 446         events = le64_to_cpu(sb->events);
 447         if (events < bitmap->mddev->events) {
 448                 printk(KERN_INFO "%s: bitmap file is out of date (%llu < %llu) "
 449                         "-- forcing full recovery\n", bmname(bitmap), events,
 450                         (unsigned long long) bitmap->mddev->events);
 451                 sb->state |= BITMAP_STALE;
 452         }
 453 success:
 454         /* assign fields using values from superblock */
 455         bitmap->chunksize = chunksize;
 456         bitmap->daemon_sleep = daemon_sleep;
 457         bitmap->flags |= sb->state;
 458         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
 459         err = 0;
 460 out:
 461         kunmap(bitmap->sb_page);
 462         if (err)
 463                 bitmap_print_sb(bitmap);
 464         return err;
 465 }
 466
 467 enum bitmap_mask_op {
 468         MASK_SET,
 469         MASK_UNSET
 470 };
 471
 472 /* record the state of the bitmap in the superblock */
 473 static void bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
 474                                 enum bitmap_mask_op op)
 475 {
 476         bitmap_super_t *sb;
 477         unsigned long flags;
 478
 479         spin_lock_irqsave(&bitmap->lock, flags);
 480         if (!bitmap || !bitmap->sb_page) { /* can't set the state */
 481                 spin_unlock_irqrestore(&bitmap->lock, flags);
 482                 return;
 483         }
 484         page_cache_get(bitmap->sb_page);
 485         spin_unlock_irqrestore(&bitmap->lock, flags);
 486         sb = (bitmap_super_t *)kmap(bitmap->sb_page);
 487         switch (op) {
 488                 case MASK_SET: sb->state |= bits;
 489                                 break;
 490                 case MASK_UNSET: sb->state &= ~bits;
 491                                 break;
 492                 default: BUG();
 493         }
 494         kunmap(bitmap->sb_page);
 495         page_cache_release(bitmap->sb_page);
 496 }
 497
 498 /*
 499  * general bitmap file operations
 500  */
 501
 502 /* calculate the index of the page that contains this bit */
 503 static inline unsigned long file_page_index(unsigned long chunk)
 504 {
 505         return CHUNK_BIT_OFFSET(chunk) >> PAGE_BIT_SHIFT;
 506 }
 507
 508 /* calculate the (bit) offset of this bit within a page */
 509 static inline unsigned long file_page_offset(unsigned long chunk)
 510 {
 511         return CHUNK_BIT_OFFSET(chunk) & (PAGE_BITS - 1);
 512 }
 513
 514 /*
 515  * return a pointer to the page in the filemap that contains the given bit
 516  *
 517  * this lookup is complicated by the fact that the bitmap sb might be exactly
 518  * 1 page (e.g., x86) or less than 1 page -- so the bitmap might start on page
 519  * 0 or page 1
 520  */
 521 static inline struct page *filemap_get_page(struct bitmap *bitmap,
 522                                         unsigned long chunk)
 523 {
 524         return bitmap->filemap[file_page_index(chunk) - file_page_index(0)];
 525 }
 526
 527
 528 static void bitmap_file_unmap(struct bitmap *bitmap)
 529 {
 530         struct page **map, *sb_page;
 531         unsigned long *attr;
 532         int pages;
 533         unsigned long flags;
 534
 535         spin_lock_irqsave(&bitmap->lock, flags);
 536         map = bitmap->filemap;
 537         bitmap->filemap = NULL;
 538         attr = bitmap->filemap_attr;
 539         bitmap->filemap_attr = NULL;
 540         pages = bitmap->file_pages;
 541         bitmap->file_pages = 0;
 542         sb_page = bitmap->sb_page;
 543         bitmap->sb_page = NULL;
 544         spin_unlock_irqrestore(&bitmap->lock, flags);
 545
 546         while (pages--)
 547                 if (map[pages]->index != 0) /* 0 is sb_page, release it below */
 548                         page_cache_release(map[pages]);
 549         kfree(map);
 550         kfree(attr);
 551
 552         if (sb_page)
 553                 page_cache_release(sb_page);
 554 }
 555
 556 static void bitmap_stop_daemons(struct bitmap *bitmap);
 557
 558 /* dequeue the next item in a page list -- don't call from irq context */
 559 static struct page_list *dequeue_page(struct bitmap *bitmap,
 560                                         struct list_head *head)
 561 {
 562         struct page_list *item = NULL;
 563
 564         spin_lock(&bitmap->write_lock);
 565         if (list_empty(head))
 566                 goto out;
 567         item = list_entry(head->prev, struct page_list, list);
 568         list_del(head->prev);
 569 out:
 570         spin_unlock(&bitmap->write_lock);
 571         return item;
 572 }
 573
 574 static void drain_write_queues(struct bitmap *bitmap)
 575 {
 576         struct list_head *queues[] = {  &bitmap->complete_pages, NULL };
 577         struct list_head *head;
 578         struct page_list *item;
 579         int i;
 580
 581         for (i = 0; queues[i]; i++) {
 582                 head = queues[i];
 583                 while ((item = dequeue_page(bitmap, head))) {
 584                         page_cache_release(item->page);
 585                         mempool_free(item, bitmap->write_pool);
 586                 }
 587         }
 588
 589         spin_lock(&bitmap->write_lock);
 590         bitmap->writes_pending = 0; /* make sure waiters continue */
 591         wake_up(&bitmap->write_wait);
 592         spin_unlock(&bitmap->write_lock);
 593 }
 594
 595 static void bitmap_file_put(struct bitmap *bitmap)
 596 {
 597         struct file *file;
 598         struct inode *inode;
 599         unsigned long flags;
 600
 601         spin_lock_irqsave(&bitmap->lock, flags);
 602         file = bitmap->file;
 603         bitmap->file = NULL;
 604         spin_unlock_irqrestore(&bitmap->lock, flags);
 605
 606         bitmap_stop_daemons(bitmap);
 607
 608         drain_write_queues(bitmap);
 609
 610         bitmap_file_unmap(bitmap);
 611
 612         if (file) {
 613                 inode = file->f_mapping->host;
 614                 spin_lock(&inode->i_lock);
 615                 atomic_set(&inode->i_writecount, 1); /* allow writes again */
 616                 spin_unlock(&inode->i_lock);
 617                 fput(file);
 618         }
 619 }
 620
 621
 622 /*
 623  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
 624  * then it is no longer reliable, so we stop using it and we mark the file
 625  * as failed in the superblock
 626  */
 627 static void bitmap_file_kick(struct bitmap *bitmap)
 628 {
 629         char *path, *ptr = NULL;
 630
 631         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET);
 632         bitmap_update_sb(bitmap);
 633
 634         path = kmalloc(PAGE_SIZE, GFP_KERNEL);
 635         if (path)
 636                 ptr = file_path(bitmap->file, path, PAGE_SIZE);
 637
 638         printk(KERN_ALERT "%s: kicking failed bitmap file %s from array!\n",
 639                 bmname(bitmap), ptr ? ptr : "");
 640
 641         kfree(path);
 642
 643         bitmap_file_put(bitmap);
 644
 645         return;
 646 }
 647
 648 enum bitmap_page_attr {
 649         BITMAP_PAGE_DIRTY = 1, // there are set bits that need to be synced
 650         BITMAP_PAGE_CLEAN = 2, // there are bits that might need to be cleared
 651         BITMAP_PAGE_NEEDWRITE=4, // there are cleared bits that need to be synced
 652 };
 653
 654 static inline void set_page_attr(struct bitmap *bitmap, struct page *page,
 655                                 enum bitmap_page_attr attr)
 656 {
 657         bitmap->filemap_attr[page->index] |= attr;
 658 }
 659
 660 static inline void clear_page_attr(struct bitmap *bitmap, struct page *page,
 661                                 enum bitmap_page_attr attr)
 662 {
 663         bitmap->filemap_attr[page->index] &= ~attr;
 664 }
 665
 666 static inline unsigned long get_page_attr(struct bitmap *bitmap, struct page *page)
 667 {
 668         return bitmap->filemap_attr[page->index];
 669 }
 670
 671 /*
 672  * bitmap_file_set_bit -- called before performing a write to the md device
 673  * to set (and eventually sync) a particular bit in the bitmap file
 674  *
 675  * we set the bit immediately, then we record the page number so that
 676  * when an unplug occurs, we can flush the dirty pages out to disk
 677  */
 678 static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 679 {
 680         unsigned long bit;
 681         struct page *page;
 682         void *kaddr;
 683         unsigned long chunk = block >> CHUNK_BLOCK_SHIFT(bitmap);
 684
 685         if (!bitmap->file || !bitmap->filemap) {
 686                 return;
 687         }
 688
 689         page = filemap_get_page(bitmap, chunk);
 690         bit = file_page_offset(chunk);
 691
 692
 693         /* make sure the page stays cached until it gets written out */
 694         if (! (get_page_attr(bitmap, page) & BITMAP_PAGE_DIRTY))
 695                 page_cache_get(page);
 696
 697         /* set the bit */
 698         kaddr = kmap_atomic(page, KM_USER0);
 699         set_bit(bit, kaddr);
 700         kunmap_atomic(kaddr, KM_USER0);
 701         PRINTK("set file bit %lu page %lu\n", bit, page->index);
 702
 703         /* record page number so it gets flushed to disk when unplug occurs */
 704         set_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 705
 706 }
 707
 708 /* this gets called when the md device is ready to unplug its underlying
 709  * (slave) device queues -- before we let any writes go down, we need to
 710  * sync the dirty pages of the bitmap file to disk */
 711 int bitmap_unplug(struct bitmap *bitmap)
 712 {
 713         unsigned long i, attr, flags;
 714         struct page *page;
 715         int wait = 0;
 716
 717         if (!bitmap)
 718                 return 0;
 719
 720         /* look at each page to see if there are any set bits that need to be
 721          * flushed out to disk */
 722         for (i = 0; i < bitmap->file_pages; i++) {
 723                 spin_lock_irqsave(&bitmap->lock, flags);
 724                 if (!bitmap->file || !bitmap->filemap) {
 725                         spin_unlock_irqrestore(&bitmap->lock, flags);
 726                         return 0;
 727                 }
 728                 page = bitmap->filemap[i];
 729                 attr = get_page_attr(bitmap, page);
 730                 clear_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 731                 clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 732                 if ((attr & BITMAP_PAGE_DIRTY))
 733                         wait = 1;
 734                 spin_unlock_irqrestore(&bitmap->lock, flags);
 735
 736                 if (attr & (BITMAP_PAGE_DIRTY | BITMAP_PAGE_NEEDWRITE))
 737                         write_page(page, 0);
 738         }
 739         if (wait) { /* if any writes were performed, we need to wait on them */
 740                 spin_lock_irq(&bitmap->write_lock);
 741                 wait_event_lock_irq(bitmap->write_wait,
 742                         bitmap->writes_pending == 0, bitmap->write_lock,
 743                         wake_up_process(bitmap->writeback_daemon->tsk));
 744                 spin_unlock_irq(&bitmap->write_lock);
 745         }
 746         return 0;
 747 }
 748
 749 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset,
 750         unsigned long sectors, int in_sync);
 751 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
 752  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
 753  * memory mapping of the bitmap file
 754  * Special cases:
 755  *   if there's no bitmap file, or if the bitmap file had been
 756  *   previously kicked from the array, we mark all the bits as
 757  *   1's in order to cause a full resync.
 758  */
 759 static int bitmap_init_from_disk(struct bitmap *bitmap, int in_sync)
 760 {
 761         unsigned long i, chunks, index, oldindex, bit;
 762         struct page *page = NULL, *oldpage = NULL;
 763         unsigned long num_pages, bit_cnt = 0;
 764         struct file *file;
 765         unsigned long bytes, offset, dummy;
 766         int outofdate;
 767         int ret = -ENOSPC;
 768
 769         chunks = bitmap->chunks;
 770         file = bitmap->file;
 771
 772         BUG_ON(!file);
 773
 774 #if INJECT_FAULTS_3
 775         outofdate = 1;
 776 #else
 777         outofdate = bitmap->flags & BITMAP_STALE;
 778 #endif
 779         if (outofdate)
 780                 printk(KERN_INFO "%s: bitmap file is out of date, doing full "
 781                         "recovery\n", bmname(bitmap));
 782
 783         bytes = (chunks + 7) / 8;
 784
 785         num_pages = (bytes + sizeof(bitmap_super_t) + PAGE_SIZE - 1) / PAGE_SIZE;
 786
 787         if (i_size_read(file->f_mapping->host) < bytes + sizeof(bitmap_super_t)) {
 788                 printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
 789                         bmname(bitmap),
 790                         (unsigned long) i_size_read(file->f_mapping->host),
 791                         bytes + sizeof(bitmap_super_t));
 792                 goto out;
 793         }
 794
 795         ret = -ENOMEM;
 796
 797         bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
 798         if (!bitmap->filemap)
 799                 goto out;
 800
 801         bitmap->filemap_attr = kmalloc(sizeof(long) * num_pages, GFP_KERNEL);
 802         if (!bitmap->filemap_attr)
 803                 goto out;
 804
 805         memset(bitmap->filemap_attr, 0, sizeof(long) * num_pages);
 806
 807         oldindex = ~0L;
 808
 809         for (i = 0; i < chunks; i++) {
 810                 index = file_page_index(i);
 811                 bit = file_page_offset(i);
 812                 if (index != oldindex) { /* this is a new page, read it in */
 813                         /* unmap the old page, we're done with it */
 814                         if (oldpage != NULL)
 815                                 kunmap(oldpage);
 816                         if (index == 0) {
 817                                 /*
 818                                  * if we're here then the superblock page
 819                                  * contains some bits (PAGE_SIZE != sizeof sb)
 820                                  * we've already read it in, so just use it
 821                                  */
 822                                 page = bitmap->sb_page;
 823                                 offset = sizeof(bitmap_super_t);
 824                         } else {
 825                                 page = read_page(file, index, &dummy);
 826                                 if (IS_ERR(page)) { /* read error */
 827                                         ret = PTR_ERR(page);
 828                                         goto out;
 829                                 }
 830                                 offset = 0;
 831                         }
 832                         oldindex = index;
 833                         oldpage = page;
 834                         kmap(page);
 835
 836                         if (outofdate) {
 837                                 /*
 838                                  * if bitmap is out of date, dirty the
 839                                  * whole page and write it out
 840                                  */
 841                                 memset(page_address(page) + offset, 0xff,
 842                                         PAGE_SIZE - offset);
 843                                 ret = write_page(page, 1);
 844                                 if (ret) {
 845                                         kunmap(page);
 846                                         /* release, page not in filemap yet */
 847                                         page_cache_release(page);
 848                                         goto out;
 849                                 }
 850                         }
 851
 852                         bitmap->filemap[bitmap->file_pages++] = page;
 853                 }
 854                 if (test_bit(bit, page_address(page))) {
 855                         /* if the disk bit is set, set the memory bit */
 856                         bitmap_set_memory_bits(bitmap,
 857                                         i << CHUNK_BLOCK_SHIFT(bitmap), 1, in_sync);
 858                         bit_cnt++;
 859                 }
 860         }
 861
 862         /* everything went OK */
 863         ret = 0;
 864         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_UNSET);
 865
 866         if (page) /* unmap the last page */
 867                 kunmap(page);
 868
 869         if (bit_cnt) { /* Kick recovery if any bits were set */
 870                 set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
 871                 md_wakeup_thread(bitmap->mddev->thread);
 872         }
 873
 874 out:
 875         printk(KERN_INFO "%s: bitmap initialized from disk: "
 876                 "read %lu/%lu pages, set %lu bits, status: %d\n",
 877                 bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt, ret);
 878
 879         return ret;
 880 }
 881
 882
 883 static void bitmap_count_page(struct bitmap *bitmap, sector_t offset, int inc)
 884 {
 885         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
 886         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
 887         bitmap->bp[page].count += inc;
 888 /*
 889         if (page == 0) printk("count page 0, offset %llu: %d gives %d\n",
 890                               (unsigned long long)offset, inc, bitmap->bp[page].count);
 891 */
 892         bitmap_checkfree(bitmap, page);
 893 }
 894 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
 895                                             sector_t offset, int *blocks,
 896                                             int create);
 897
 898 /*
 899  * bitmap daemon -- periodically wakes up to clean bits and flush pages
 900  *                      out to disk
 901  */
 902
 903 int bitmap_daemon_work(struct bitmap *bitmap)
 904 {
 905         unsigned long bit, j;
 906         unsigned long flags;
 907         struct page *page = NULL, *lastpage = NULL;
 908         int err = 0;
 909         int blocks;
 910         int attr;
 911
 912         if (bitmap == NULL)
 913                 return 0;
 914         if (time_before(jiffies, bitmap->daemon_lastrun + bitmap->daemon_sleep*HZ))
 915                 return 0;
 916         bitmap->daemon_lastrun = jiffies;
 917
 918         for (j = 0; j < bitmap->chunks; j++) {
 919                 bitmap_counter_t *bmc;
 920                 spin_lock_irqsave(&bitmap->lock, flags);
 921                 if (!bitmap->file || !bitmap->filemap) {
 922                         /* error or shutdown */
 923                         spin_unlock_irqrestore(&bitmap->lock, flags);
 924                         break;
 925                 }
 926
 927                 page = filemap_get_page(bitmap, j);
 928                 /* skip this page unless it's marked as needing cleaning */
 929                 if (!((attr=get_page_attr(bitmap, page)) & BITMAP_PAGE_CLEAN)) {
 930                         if (attr & BITMAP_PAGE_NEEDWRITE) {
 931                                 page_cache_get(page);
 932                                 clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 933                         }
 934                         spin_unlock_irqrestore(&bitmap->lock, flags);
 935                         if (attr & BITMAP_PAGE_NEEDWRITE) {
 936                                 if (write_page(page, 0))
 937                                         bitmap_file_kick(bitmap);
 938                                 page_cache_release(page);
 939                         }
 940                         continue;
 941                 }
 942
 943                 bit = file_page_offset(j);
 944
 945                 if (page != lastpage) {
 946                         /* grab the new page, sync and release the old */
 947                         page_cache_get(page);
 948                         if (lastpage != NULL) {
 949                                 if (get_page_attr(bitmap, lastpage) & BITMAP_PAGE_NEEDWRITE) {
 950                                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
 951                                         spin_unlock_irqrestore(&bitmap->lock, flags);
 952                                         write_page(lastpage, 0);
 953                                 } else {
 954                                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
 955                                         spin_unlock_irqrestore(&bitmap->lock, flags);
 956                                 }
 957                                 kunmap(lastpage);
 958                                 page_cache_release(lastpage);
 959                                 if (err)
 960                                         bitmap_file_kick(bitmap);
 961                         } else
 962                                 spin_unlock_irqrestore(&bitmap->lock, flags);
 963                         lastpage = page;
 964                         kmap(page);
 965 /*
 966                         printk("bitmap clean at page %lu\n", j);
 967 */
 968                         spin_lock_irqsave(&bitmap->lock, flags);
 969                         clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
 970                 }
 971                 bmc = bitmap_get_counter(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
 972                                         &blocks, 0);
 973                 if (bmc) {
 974 /*
 975   if (j < 100) printk("bitmap: j=%lu, *bmc = 0x%x\n", j, *bmc);
 976 */
 977                         if (*bmc == 2) {
 978                                 *bmc=1; /* maybe clear the bit next time */
 979                                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
 980                         } else if (*bmc == 1) {
 981                                 /* we can clear the bit */
 982                                 *bmc = 0;
 983                                 bitmap_count_page(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
 984                                                   -1);
 985
 986                                 /* clear the bit */
 987                                 clear_bit(bit, page_address(page));
 988                         }
 989                 }
 990                 spin_unlock_irqrestore(&bitmap->lock, flags);
 991         }
 992
 993         /* now sync the final page */
 994         if (lastpage != NULL) {
 995                 kunmap(lastpage);
 996                 spin_lock_irqsave(&bitmap->lock, flags);
 997                 if (get_page_attr(bitmap, lastpage) &BITMAP_PAGE_NEEDWRITE) {
 998                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
 999                         spin_unlock_irqrestore(&bitmap->lock, flags);
1000                         write_page(lastpage, 0);
1001                 } else {
1002                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1003                         spin_unlock_irqrestore(&bitmap->lock, flags);
1004                 }
1005
1006                 page_cache_release(lastpage);
1007         }
1008
1009         return err;
1010 }
1011
1012 static void daemon_exit(struct bitmap *bitmap, mdk_thread_t **daemon)
1013 {
1014         mdk_thread_t *dmn;
1015         unsigned long flags;
1016
1017         /* if no one is waiting on us, we'll free the md thread struct
1018          * and exit, otherwise we let the waiter clean things up */
1019         spin_lock_irqsave(&bitmap->lock, flags);
1020         if ((dmn = *daemon)) { /* no one is waiting, cleanup and exit */
1021                 *daemon = NULL;
1022                 spin_unlock_irqrestore(&bitmap->lock, flags);
1023                 kfree(dmn);
1024                 complete_and_exit(NULL, 0); /* do_exit not exported */
1025         }
1026         spin_unlock_irqrestore(&bitmap->lock, flags);
1027 }
1028
1029 static void bitmap_writeback_daemon(mddev_t *mddev)
1030 {
1031         struct bitmap *bitmap = mddev->bitmap;
1032         struct page *page;
1033         struct page_list *item;
1034         int err = 0;
1035
1036         while (1) {
1037                 PRINTK("%s: bitmap writeback daemon waiting...\n", bmname(bitmap));
1038                 down_interruptible(&bitmap->write_done);
1039                 if (signal_pending(current)) {
1040                         printk(KERN_INFO
1041                             "%s: bitmap writeback daemon got signal, exiting...\n",
1042                             bmname(bitmap));
1043                         break;
1044                 }
1045
1046                 PRINTK("%s: bitmap writeback daemon woke up...\n", bmname(bitmap));
1047                 /* wait on bitmap page writebacks */
1048                 while ((item = dequeue_page(bitmap, &bitmap->complete_pages))) {
1049                         page = item->page;
1050                         mempool_free(item, bitmap->write_pool);
1051                         PRINTK("wait on page writeback: %p %lu\n", page, bitmap->writes_pending);
1052                         wait_on_page_writeback(page);
1053                         PRINTK("finished page writeback: %p %lu\n", page, bitmap->writes_pending);
1054                         spin_lock(&bitmap->write_lock);
1055                         if (!--bitmap->writes_pending)
1056                                 wake_up(&bitmap->write_wait);
1057                         spin_unlock(&bitmap->write_lock);
1058                         err = PageError(page);
1059                         page_cache_release(page);
1060                         if (err) {
1061                                 printk(KERN_WARNING "%s: bitmap file writeback "
1062                                         "failed (page %lu): %d\n",
1063                                         bmname(bitmap), page->index, err);
1064                                 bitmap_file_kick(bitmap);
1065                                 goto out;
1066                         }
1067                 }
1068         }
1069 out:
1070         if (err) {
1071                 printk(KERN_INFO "%s: bitmap writeback daemon exiting (%d)\n",
1072                         bmname(bitmap), err);
1073                 daemon_exit(bitmap, &bitmap->writeback_daemon);
1074         }
1075         return;
1076 }
1077
1078 static int bitmap_start_daemon(struct bitmap *bitmap, mdk_thread_t **ptr,
1079                                 void (*func)(mddev_t *), char *name)
1080 {
1081         mdk_thread_t *daemon;
1082         unsigned long flags;
1083         char namebuf[32];
1084
1085         spin_lock_irqsave(&bitmap->lock, flags);
1086         *ptr = NULL;
1087         if (!bitmap->file) /* no need for daemon if there's no backing file */
1088                 goto out_unlock;
1089
1090         spin_unlock_irqrestore(&bitmap->lock, flags);
1091
1092 #if INJECT_FATAL_FAULT_2
1093         daemon = NULL;
1094 #else
1095         sprintf(namebuf, "%%s_%s", name);
1096         daemon = md_register_thread(func, bitmap->mddev, namebuf);
1097 #endif
1098         if (!daemon) {
1099                 printk(KERN_ERR "%s: failed to start bitmap daemon\n",
1100                         bmname(bitmap));
1101                 return -ECHILD;
1102         }
1103
1104         spin_lock_irqsave(&bitmap->lock, flags);
1105         *ptr = daemon;
1106
1107         md_wakeup_thread(daemon); /* start it running */
1108
1109         PRINTK("%s: %s daemon (pid %d) started...\n",
1110                 bmname(bitmap), name, daemon->tsk->pid);
1111 out_unlock:
1112         spin_unlock_irqrestore(&bitmap->lock, flags);
1113         return 0;
1114 }
1115
1116 static int bitmap_start_daemons(struct bitmap *bitmap)
1117 {
1118         int err = bitmap_start_daemon(bitmap, &bitmap->writeback_daemon,
1119                                         bitmap_writeback_daemon, "bitmap_wb");
1120         return err;
1121 }
1122
1123 static void bitmap_stop_daemon(struct bitmap *bitmap, mdk_thread_t **ptr)
1124 {
1125         mdk_thread_t *daemon;
1126         unsigned long flags;
1127
1128         spin_lock_irqsave(&bitmap->lock, flags);
1129         daemon = *ptr;
1130         *ptr = NULL;
1131         spin_unlock_irqrestore(&bitmap->lock, flags);
1132         if (daemon)
1133                 md_unregister_thread(daemon); /* destroy the thread */
1134 }
1135
1136 static void bitmap_stop_daemons(struct bitmap *bitmap)
1137 {
1138         /* the daemons can't stop themselves... they'll just exit instead... */
1139         if (bitmap->writeback_daemon &&
1140             current->pid != bitmap->writeback_daemon->tsk->pid)
1141                 bitmap_stop_daemon(bitmap, &bitmap->writeback_daemon);
1142 }
1143
1144 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1145                                             sector_t offset, int *blocks,
1146                                             int create)
1147 {
1148         /* If 'create', we might release the lock and reclaim it.
1149          * The lock must have been taken with interrupts enabled.
1150          * If !create, we don't release the lock.
1151          */
1152         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1153         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1154         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1155         sector_t csize;
1156
1157         if (bitmap_checkpage(bitmap, page, create) < 0) {
1158                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1159                 *blocks = csize - (offset & (csize- 1));
1160                 return NULL;
1161         }
1162         /* now locked ... */
1163
1164         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1165                 /* should we use the first or second counter field
1166                  * of the hijacked pointer? */
1167                 int hi = (pageoff > PAGE_COUNTER_MASK);
1168                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap) +
1169                                           PAGE_COUNTER_SHIFT - 1);
1170                 *blocks = csize - (offset & (csize- 1));
1171                 return  &((bitmap_counter_t *)
1172                           &bitmap->bp[page].map)[hi];
1173         } else { /* page is allocated */
1174                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1175                 *blocks = csize - (offset & (csize- 1));
1176                 return (bitmap_counter_t *)
1177                         &(bitmap->bp[page].map[pageoff]);
1178         }
1179 }
1180
1181 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors)
1182 {
1183         if (!bitmap) return 0;
1184         while (sectors) {
1185                 int blocks;
1186                 bitmap_counter_t *bmc;
1187
1188                 spin_lock_irq(&bitmap->lock);
1189                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 1);
1190                 if (!bmc) {
1191                         spin_unlock_irq(&bitmap->lock);
1192                         return 0;
1193                 }
1194
1195                 switch(*bmc) {
1196                 case 0:
1197                         bitmap_file_set_bit(bitmap, offset);
1198                         bitmap_count_page(bitmap,offset, 1);
1199                         blk_plug_device(bitmap->mddev->queue);
1200                         /* fall through */
1201                 case 1:
1202                         *bmc = 2;
1203                 }
1204                 if ((*bmc & COUNTER_MAX) == COUNTER_MAX) BUG();
1205                 (*bmc)++;
1206
1207                 spin_unlock_irq(&bitmap->lock);
1208
1209                 offset += blocks;
1210                 if (sectors > blocks)
1211                         sectors -= blocks;
1212                 else sectors = 0;
1213         }
1214         return 0;
1215 }
1216
1217 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1218                      int success)
1219 {
1220         if (!bitmap) return;
1221         while (sectors) {
1222                 int blocks;
1223                 unsigned long flags;
1224                 bitmap_counter_t *bmc;
1225
1226                 spin_lock_irqsave(&bitmap->lock, flags);
1227                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 0);
1228                 if (!bmc) {
1229                         spin_unlock_irqrestore(&bitmap->lock, flags);
1230                         return;
1231                 }
1232
1233                 if (!success && ! (*bmc & NEEDED_MASK))
1234                         *bmc |= NEEDED_MASK;
1235
1236                 (*bmc)--;
1237                 if (*bmc <= 2) {
1238                         set_page_attr(bitmap,
1239                                       filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1240                                       BITMAP_PAGE_CLEAN);
1241                 }
1242                 spin_unlock_irqrestore(&bitmap->lock, flags);
1243                 offset += blocks;
1244                 if (sectors > blocks)
1245                         sectors -= blocks;
1246                 else sectors = 0;
1247         }
1248 }
1249
1250 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks)
1251 {
1252         bitmap_counter_t *bmc;
1253         int rv;
1254         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1255                 *blocks = 1024;
1256                 return 1; /* always resync if no bitmap */
1257         }
1258         spin_lock_irq(&bitmap->lock);
1259         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1260         rv = 0;
1261         if (bmc) {
1262                 /* locked */
1263                 if (RESYNC(*bmc))
1264                         rv = 1;
1265                 else if (NEEDED(*bmc)) {
1266                         rv = 1;
1267                         *bmc |= RESYNC_MASK;
1268                         *bmc &= ~NEEDED_MASK;
1269                 }
1270         }
1271         spin_unlock_irq(&bitmap->lock);
1272         return rv;
1273 }
1274
1275 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int aborted)
1276 {
1277         bitmap_counter_t *bmc;
1278         unsigned long flags;
1279 /*
1280         if (offset == 0) printk("bitmap_end_sync 0 (%d)\n", aborted);
1281 */      if (bitmap == NULL) {
1282                 *blocks = 1024;
1283                 return;
1284         }
1285         spin_lock_irqsave(&bitmap->lock, flags);
1286         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1287         if (bmc == NULL)
1288                 goto unlock;
1289         /* locked */
1290 /*
1291         if (offset == 0) printk("bitmap_end sync found 0x%x, blocks %d\n", *bmc, *blocks);
1292 */
1293         if (RESYNC(*bmc)) {
1294                 *bmc &= ~RESYNC_MASK;
1295
1296                 if (!NEEDED(*bmc) && aborted)
1297                         *bmc |= NEEDED_MASK;
1298                 else {
1299                         if (*bmc <= 2) {
1300                                 set_page_attr(bitmap,
1301                                               filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1302                                               BITMAP_PAGE_CLEAN);
1303                         }
1304                 }
1305         }
1306  unlock:
1307         spin_unlock_irqrestore(&bitmap->lock, flags);
1308 }
1309
1310 void bitmap_close_sync(struct bitmap *bitmap)
1311 {
1312         /* Sync has finished, and any bitmap chunks that weren't synced
1313          * properly have been aborted.  It remains to us to clear the
1314          * RESYNC bit wherever it is still on
1315          */
1316         sector_t sector = 0;
1317         int blocks;
1318         if (!bitmap) return;
1319         while (sector < bitmap->mddev->resync_max_sectors) {
1320                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1321 /*
1322                 if (sector < 500) printk("bitmap_close_sync: sec %llu blks %d\n",
1323                                          (unsigned long long)sector, blocks);
1324 */              sector += blocks;
1325         }
1326 }
1327
1328 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset,
1329                                    unsigned long sectors, int in_sync)
1330 {
1331         /* For each chunk covered by any of these sectors, set the
1332          * counter to 1 and set resync_needed unless in_sync.  They should all
1333          * be 0 at this point
1334          */
1335         while (sectors) {
1336                 int secs;
1337                 bitmap_counter_t *bmc;
1338                 spin_lock_irq(&bitmap->lock);
1339                 bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
1340                 if (!bmc) {
1341                         spin_unlock_irq(&bitmap->lock);
1342                         return;
1343                 }
1344                 if (! *bmc) {
1345                         struct page *page;
1346                         *bmc = 1 | (in_sync? 0 : NEEDED_MASK);
1347                         bitmap_count_page(bitmap, offset, 1);
1348                         page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));
1349                         set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1350                 }
1351                 spin_unlock_irq(&bitmap->lock);
1352                 if (sectors > secs)
1353                         sectors -= secs;
1354                 else
1355                         sectors = 0;
1356         }
1357 }
1358
1359 /* dirty the entire bitmap */
1360 int bitmap_setallbits(struct bitmap *bitmap)
1361 {
1362         unsigned long flags;
1363         unsigned long j;
1364
1365         /* dirty the in-memory bitmap */
1366         bitmap_set_memory_bits(bitmap, 0, bitmap->chunks << CHUNK_BLOCK_SHIFT(bitmap), 1);
1367
1368         /* dirty the bitmap file */
1369         for (j = 0; j < bitmap->file_pages; j++) {
1370                 struct page *page = bitmap->filemap[j];
1371
1372                 spin_lock_irqsave(&bitmap->lock, flags);
1373                 page_cache_get(page);
1374                 spin_unlock_irqrestore(&bitmap->lock, flags);
1375                 memset(kmap(page), 0xff, PAGE_SIZE);
1376                 kunmap(page);
1377                 write_page(page, 0);
1378         }
1379
1380         return 0;
1381 }
1382
1383 /*
1384  * free memory that was allocated
1385  */
1386 void bitmap_destroy(mddev_t *mddev)
1387 {
1388         unsigned long k, pages;
1389         struct bitmap_page *bp;
1390         struct bitmap *bitmap = mddev->bitmap;
1391
1392         if (!bitmap) /* there was no bitmap */
1393                 return;
1394
1395         mddev->bitmap = NULL; /* disconnect from the md device */
1396
1397         /* release the bitmap file and kill the daemon */
1398         bitmap_file_put(bitmap);
1399
1400         bp = bitmap->bp;
1401         pages = bitmap->pages;
1402
1403         /* free all allocated memory */
1404
1405         mempool_destroy(bitmap->write_pool);
1406
1407         if (bp) /* deallocate the page memory */
1408                 for (k = 0; k < pages; k++)
1409                         if (bp[k].map && !bp[k].hijacked)
1410                                 kfree(bp[k].map);
1411         kfree(bp);
1412         kfree(bitmap);
1413 }
1414
1415 /*
1416  * initialize the bitmap structure
1417  * if this returns an error, bitmap_destroy must be called to do clean up
1418  */
1419 int bitmap_create(mddev_t *mddev)
1420 {
1421         struct bitmap *bitmap;
1422         unsigned long blocks = mddev->resync_max_sectors;
1423         unsigned long chunks;
1424         unsigned long pages;
1425         struct file *file = mddev->bitmap_file;
1426         int err;
1427
1428         BUG_ON(sizeof(bitmap_super_t) != 256);
1429
1430         if (!file) /* bitmap disabled, nothing to do */
1431                 return 0;
1432
1433         bitmap = kmalloc(sizeof(*bitmap), GFP_KERNEL);
1434         if (!bitmap)
1435                 return -ENOMEM;
1436
1437         memset(bitmap, 0, sizeof(*bitmap));
1438
1439         spin_lock_init(&bitmap->lock);
1440         bitmap->mddev = mddev;
1441         mddev->bitmap = bitmap;
1442
1443         spin_lock_init(&bitmap->write_lock);
1444         init_MUTEX_LOCKED(&bitmap->write_done);
1445         INIT_LIST_HEAD(&bitmap->complete_pages);
1446         init_waitqueue_head(&bitmap->write_wait);
1447         bitmap->write_pool = mempool_create(WRITE_POOL_SIZE, write_pool_alloc,
1448                                 write_pool_free, NULL);
1449         if (!bitmap->write_pool)
1450                 return -ENOMEM;
1451
1452         bitmap->file = file;
1453         get_file(file);
1454         /* read superblock from bitmap file (this sets bitmap->chunksize) */
1455         err = bitmap_read_sb(bitmap);
1456         if (err)
1457                 return err;
1458
1459         bitmap->chunkshift = find_first_bit(&bitmap->chunksize,
1460                                         sizeof(bitmap->chunksize));
1461
1462         /* now that chunksize and chunkshift are set, we can use these macros */
1463         chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) /
1464                         CHUNK_BLOCK_RATIO(bitmap);
1465         pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
1466
1467         BUG_ON(!pages);
1468
1469         bitmap->chunks = chunks;
1470         bitmap->pages = pages;
1471         bitmap->missing_pages = pages;
1472         bitmap->counter_bits = COUNTER_BITS;
1473
1474         bitmap->syncchunk = ~0UL;
1475
1476 #if INJECT_FATAL_FAULT_1
1477         bitmap->bp = NULL;
1478 #else
1479         bitmap->bp = kmalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
1480 #endif
1481         if (!bitmap->bp)
1482                 return -ENOMEM;
1483         memset(bitmap->bp, 0, pages * sizeof(*bitmap->bp));
1484
1485         bitmap->flags |= BITMAP_ACTIVE;
1486
1487         /* now that we have some pages available, initialize the in-memory
1488          * bitmap from the on-disk bitmap */
1489         err = bitmap_init_from_disk(bitmap, mddev->recovery_cp == MaxSector);
1490         if (err)
1491                 return err;
1492
1493         printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
1494                 pages, bmname(bitmap));
1495
1496         /* kick off the bitmap daemons */
1497         err = bitmap_start_daemons(bitmap);
1498         if (err)
1499                 return err;
1500         return bitmap_update_sb(bitmap);
1501 }
1502
1503 /* the bitmap API -- for raid personalities */
1504 EXPORT_SYMBOL(bitmap_startwrite);
1505 EXPORT_SYMBOL(bitmap_endwrite);
1506 EXPORT_SYMBOL(bitmap_start_sync);
1507 EXPORT_SYMBOL(bitmap_end_sync);
1508 EXPORT_SYMBOL(bitmap_unplug);
1509 EXPORT_SYMBOL(bitmap_close_sync);
1510 EXPORT_SYMBOL(bitmap_daemon_work);