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  */
  18
  19 #include <linux/module.h>
  20 #include <linux/errno.h>
  21 #include <linux/slab.h>
  22 #include <linux/init.h>
  23 #include <linux/timer.h>
  24 #include <linux/sched.h>
  25 #include <linux/list.h>
  26 #include <linux/file.h>
  27 #include <linux/mount.h>
  28 #include <linux/buffer_head.h>
  29 #include <linux/raid/md.h>
  30 #include <linux/raid/bitmap.h>
  31
  32 /* debug macros */
  33
  34 #define DEBUG 0
  35
  36 #if DEBUG
  37 /* these are for debugging purposes only! */
  38
  39 /* define one and only one of these */
  40 #define INJECT_FAULTS_1 0 /* cause bitmap_alloc_page to fail always */
  41 #define INJECT_FAULTS_2 0 /* cause bitmap file to be kicked when first bit set*/
  42 #define INJECT_FAULTS_3 0 /* treat bitmap file as kicked at init time */
  43 #define INJECT_FAULTS_4 0 /* undef */
  44 #define INJECT_FAULTS_5 0 /* undef */
  45 #define INJECT_FAULTS_6 0
  46
  47 /* if these are defined, the driver will fail! debug only */
  48 #define INJECT_FATAL_FAULT_1 0 /* fail kmalloc, causing bitmap_create to fail */
  49 #define INJECT_FATAL_FAULT_2 0 /* undef */
  50 #define INJECT_FATAL_FAULT_3 0 /* undef */
  51 #endif
  52
  53 //#define DPRINTK PRINTK /* set this NULL to avoid verbose debug output */
  54 #define DPRINTK(x...) do { } while(0)
  55
  56 #ifndef PRINTK
  57 #  if DEBUG > 0
  58 #    define PRINTK(x...) printk(KERN_DEBUG x)
  59 #  else
  60 #    define PRINTK(x...)
  61 #  endif
  62 #endif
  63
  64 static inline char * bmname(struct bitmap *bitmap)
  65 {
  66         return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
  67 }
  68
  69
  70 /*
  71  * just a placeholder - calls kmalloc for bitmap pages
  72  */
  73 static unsigned char *bitmap_alloc_page(struct bitmap *bitmap)
  74 {
  75         unsigned char *page;
  76
  77 #ifdef INJECT_FAULTS_1
  78         page = NULL;
  79 #else
  80         page = kmalloc(PAGE_SIZE, GFP_NOIO);
  81 #endif
  82         if (!page)
  83                 printk("%s: bitmap_alloc_page FAILED\n", bmname(bitmap));
  84         else
  85                 PRINTK("%s: bitmap_alloc_page: allocated page at %p\n",
  86                         bmname(bitmap), page);
  87         return page;
  88 }
  89
  90 /*
  91  * for now just a placeholder -- just calls kfree for bitmap pages
  92  */
  93 static void bitmap_free_page(struct bitmap *bitmap, unsigned char *page)
  94 {
  95         PRINTK("%s: bitmap_free_page: free page %p\n", bmname(bitmap), page);
  96         kfree(page);
  97 }
  98
  99 /*
 100  * check a page and, if necessary, allocate it (or hijack it if the alloc fails)
 101  *
 102  * 1) check to see if this page is allocated, if it's not then try to alloc
 103  * 2) if the alloc fails, set the page's hijacked flag so we'll use the
 104  *    page pointer directly as a counter
 105  *
 106  * if we find our page, we increment the page's refcount so that it stays
 107  * allocated while we're using it
 108  */
 109 static int bitmap_checkpage(struct bitmap *bitmap, unsigned long page, int create)
 110 {
 111         unsigned char *mappage;
 112
 113         if (page >= bitmap->pages) {
 114                 printk(KERN_ALERT
 115                         "%s: invalid bitmap page request: %lu (> %lu)\n",
 116                         bmname(bitmap), page, bitmap->pages-1);
 117                 return -EINVAL;
 118         }
 119
 120
 121         if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
 122                 return 0;
 123
 124         if (bitmap->bp[page].map) /* page is already allocated, just return */
 125                 return 0;
 126
 127         if (!create)
 128                 return -ENOENT;
 129
 130         spin_unlock_irq(&bitmap->lock);
 131
 132         /* this page has not been allocated yet */
 133
 134         if ((mappage = bitmap_alloc_page(bitmap)) == NULL) {
 135                 PRINTK("%s: bitmap map page allocation failed, hijacking\n",
 136                         bmname(bitmap));
 137                 /* failed - set the hijacked flag so that we can use the
 138                  * pointer as a counter */
 139                 spin_lock_irq(&bitmap->lock);
 140                 if (!bitmap->bp[page].map)
 141                         bitmap->bp[page].hijacked = 1;
 142                 goto out;
 143         }
 144
 145         /* got a page */
 146
 147         spin_lock_irq(&bitmap->lock);
 148
 149         /* recheck the page */
 150
 151         if (bitmap->bp[page].map || bitmap->bp[page].hijacked) {
 152                 /* somebody beat us to getting the page */
 153                 bitmap_free_page(bitmap, mappage);
 154                 return 0;
 155         }
 156
 157         /* no page was in place and we have one, so install it */
 158
 159         memset(mappage, 0, PAGE_SIZE);
 160         bitmap->bp[page].map = mappage;
 161         bitmap->missing_pages--;
 162 out:
 163         return 0;
 164 }
 165
 166
 167 /* if page is completely empty, put it back on the free list, or dealloc it */
 168 /* if page was hijacked, unmark the flag so it might get alloced next time */
 169 /* Note: lock should be held when calling this */
 170 static void bitmap_checkfree(struct bitmap *bitmap, unsigned long page)
 171 {
 172         char *ptr;
 173
 174         if (bitmap->bp[page].count) /* page is still busy */
 175                 return;
 176
 177         /* page is no longer in use, it can be released */
 178
 179         if (bitmap->bp[page].hijacked) { /* page was hijacked, undo this now */
 180                 bitmap->bp[page].hijacked = 0;
 181                 bitmap->bp[page].map = NULL;
 182                 return;
 183         }
 184
 185         /* normal case, free the page */
 186
 187 #if 0
 188 /* actually ... let's not.  We will probably need the page again exactly when
 189  * memory is tight and we are flusing to disk
 190  */
 191         return;
 192 #else
 193         ptr = bitmap->bp[page].map;
 194         bitmap->bp[page].map = NULL;
 195         bitmap->missing_pages++;
 196         bitmap_free_page(bitmap, ptr);
 197         return;
 198 #endif
 199 }
 200
 201
 202 /*
 203  * bitmap file handling - read and write the bitmap file and its superblock
 204  */
 205
 206 /*
 207  * basic page I/O operations
 208  */
 209
 210 /* IO operations when bitmap is stored near all superblocks */
 211 static struct page *read_sb_page(mddev_t *mddev, long offset, unsigned long index)
 212 {
 213         /* choose a good rdev and read the page from there */
 214
 215         mdk_rdev_t *rdev;
 216         struct list_head *tmp;
 217         struct page *page = alloc_page(GFP_KERNEL);
 218         sector_t target;
 219
 220         if (!page)
 221                 return ERR_PTR(-ENOMEM);
 222
 223         rdev_for_each(rdev, tmp, mddev) {
 224                 if (! test_bit(In_sync, &rdev->flags)
 225                     || test_bit(Faulty, &rdev->flags))
 226                         continue;
 227
 228                 target = rdev->sb_start + offset + index * (PAGE_SIZE/512);
 229
 230                 if (sync_page_io(rdev->bdev, target, PAGE_SIZE, page, READ)) {
 231                         page->index = index;
 232                         attach_page_buffers(page, NULL); /* so that free_buffer will
 233                                                           * quietly no-op */
 234                         return page;
 235                 }
 236         }
 237         return ERR_PTR(-EIO);
 238
 239 }
 240
 241 static mdk_rdev_t *next_active_rdev(mdk_rdev_t *rdev, mddev_t *mddev)
 242 {
 243         /* Iterate the disks of an mddev, using rcu to protect access to the
 244          * linked list, and raising the refcount of devices we return to ensure
 245          * they don't disappear while in use.
 246          * As devices are only added or removed when raid_disk is < 0 and
 247          * nr_pending is 0 and In_sync is clear, the entries we return will
 248          * still be in the same position on the list when we re-enter
 249          * list_for_each_continue_rcu.
 250          */
 251         struct list_head *pos;
 252         rcu_read_lock();
 253         if (rdev == NULL)
 254                 /* start at the beginning */
 255                 pos = &mddev->disks;
 256         else {
 257                 /* release the previous rdev and start from there. */
 258                 rdev_dec_pending(rdev, mddev);
 259                 pos = &rdev->same_set;
 260         }
 261         list_for_each_continue_rcu(pos, &mddev->disks) {
 262                 rdev = list_entry(pos, mdk_rdev_t, same_set);
 263                 if (rdev->raid_disk >= 0 &&
 264                     test_bit(In_sync, &rdev->flags) &&
 265                     !test_bit(Faulty, &rdev->flags)) {
 266                         /* this is a usable devices */
 267                         atomic_inc(&rdev->nr_pending);
 268                         rcu_read_unlock();
 269                         return rdev;
 270                 }
 271         }
 272         rcu_read_unlock();
 273         return NULL;
 274 }
 275
 276 static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
 277 {
 278         mdk_rdev_t *rdev = NULL;
 279         mddev_t *mddev = bitmap->mddev;
 280
 281         while ((rdev = next_active_rdev(rdev, mddev)) != NULL) {
 282                         int size = PAGE_SIZE;
 283                         if (page->index == bitmap->file_pages-1)
 284                                 size = roundup(bitmap->last_page_size,
 285                                                bdev_hardsect_size(rdev->bdev));
 286                         /* Just make sure we aren't corrupting data or
 287                          * metadata
 288                          */
 289                         if (bitmap->offset < 0) {
 290                                 /* DATA  BITMAP METADATA  */
 291                                 if (bitmap->offset
 292                                     + (long)(page->index * (PAGE_SIZE/512))
 293                                     + size/512 > 0)
 294                                         /* bitmap runs in to metadata */
 295                                         goto bad_alignment;
 296                                 if (rdev->data_offset + mddev->size*2
 297                                     > rdev->sb_start + bitmap->offset)
 298                                         /* data runs in to bitmap */
 299                                         goto bad_alignment;
 300                         } else if (rdev->sb_start < rdev->data_offset) {
 301                                 /* METADATA BITMAP DATA */
 302                                 if (rdev->sb_start
 303                                     + bitmap->offset
 304                                     + page->index*(PAGE_SIZE/512) + size/512
 305                                     > rdev->data_offset)
 306                                         /* bitmap runs in to data */
 307                                         goto bad_alignment;
 308                         } else {
 309                                 /* DATA METADATA BITMAP - no problems */
 310                         }
 311                         md_super_write(mddev, rdev,
 312                                        rdev->sb_start + bitmap->offset
 313                                        + page->index * (PAGE_SIZE/512),
 314                                        size,
 315                                        page);
 316         }
 317
 318         if (wait)
 319                 md_super_wait(mddev);
 320         return 0;
 321
 322  bad_alignment:
 323         rcu_read_unlock();
 324         return -EINVAL;
 325 }
 326
 327 static void bitmap_file_kick(struct bitmap *bitmap);
 328 /*
 329  * write out a page to a file
 330  */
 331 static void write_page(struct bitmap *bitmap, struct page *page, int wait)
 332 {
 333         struct buffer_head *bh;
 334
 335         if (bitmap->file == NULL) {
 336                 switch (write_sb_page(bitmap, page, wait)) {
 337                 case -EINVAL:
 338                         bitmap->flags |= BITMAP_WRITE_ERROR;
 339                 }
 340         } else {
 341
 342                 bh = page_buffers(page);
 343
 344                 while (bh && bh->b_blocknr) {
 345                         atomic_inc(&bitmap->pending_writes);
 346                         set_buffer_locked(bh);
 347                         set_buffer_mapped(bh);
 348                         submit_bh(WRITE, bh);
 349                         bh = bh->b_this_page;
 350                 }
 351
 352                 if (wait) {
 353                         wait_event(bitmap->write_wait,
 354                                    atomic_read(&bitmap->pending_writes)==0);
 355                 }
 356         }
 357         if (bitmap->flags & BITMAP_WRITE_ERROR)
 358                 bitmap_file_kick(bitmap);
 359 }
 360
 361 static void end_bitmap_write(struct buffer_head *bh, int uptodate)
 362 {
 363         struct bitmap *bitmap = bh->b_private;
 364         unsigned long flags;
 365
 366         if (!uptodate) {
 367                 spin_lock_irqsave(&bitmap->lock, flags);
 368                 bitmap->flags |= BITMAP_WRITE_ERROR;
 369                 spin_unlock_irqrestore(&bitmap->lock, flags);
 370         }
 371         if (atomic_dec_and_test(&bitmap->pending_writes))
 372                 wake_up(&bitmap->write_wait);
 373 }
 374
 375 /* copied from buffer.c */
 376 static void
 377 __clear_page_buffers(struct page *page)
 378 {
 379         ClearPagePrivate(page);
 380         set_page_private(page, 0);
 381         page_cache_release(page);
 382 }
 383 static void free_buffers(struct page *page)
 384 {
 385         struct buffer_head *bh = page_buffers(page);
 386
 387         while (bh) {
 388                 struct buffer_head *next = bh->b_this_page;
 389                 free_buffer_head(bh);
 390                 bh = next;
 391         }
 392         __clear_page_buffers(page);
 393         put_page(page);
 394 }
 395
 396 /* read a page from a file.
 397  * We both read the page, and attach buffers to the page to record the
 398  * address of each block (using bmap).  These addresses will be used
 399  * to write the block later, completely bypassing the filesystem.
 400  * This usage is similar to how swap files are handled, and allows us
 401  * to write to a file with no concerns of memory allocation failing.
 402  */
 403 static struct page *read_page(struct file *file, unsigned long index,
 404                               struct bitmap *bitmap,
 405                               unsigned long count)
 406 {
 407         struct page *page = NULL;
 408         struct inode *inode = file->f_path.dentry->d_inode;
 409         struct buffer_head *bh;
 410         sector_t block;
 411
 412         PRINTK("read bitmap file (%dB @ %Lu)\n", (int)PAGE_SIZE,
 413                         (unsigned long long)index << PAGE_SHIFT);
 414
 415         page = alloc_page(GFP_KERNEL);
 416         if (!page)
 417                 page = ERR_PTR(-ENOMEM);
 418         if (IS_ERR(page))
 419                 goto out;
 420
 421         bh = alloc_page_buffers(page, 1<<inode->i_blkbits, 0);
 422         if (!bh) {
 423                 put_page(page);
 424                 page = ERR_PTR(-ENOMEM);
 425                 goto out;
 426         }
 427         attach_page_buffers(page, bh);
 428         block = index << (PAGE_SHIFT - inode->i_blkbits);
 429         while (bh) {
 430                 if (count == 0)
 431                         bh->b_blocknr = 0;
 432                 else {
 433                         bh->b_blocknr = bmap(inode, block);
 434                         if (bh->b_blocknr == 0) {
 435                                 /* Cannot use this file! */
 436                                 free_buffers(page);
 437                                 page = ERR_PTR(-EINVAL);
 438                                 goto out;
 439                         }
 440                         bh->b_bdev = inode->i_sb->s_bdev;
 441                         if (count < (1<<inode->i_blkbits))
 442                                 count = 0;
 443                         else
 444                                 count -= (1<<inode->i_blkbits);
 445
 446                         bh->b_end_io = end_bitmap_write;
 447                         bh->b_private = bitmap;
 448                         atomic_inc(&bitmap->pending_writes);
 449                         set_buffer_locked(bh);
 450                         set_buffer_mapped(bh);
 451                         submit_bh(READ, bh);
 452                 }
 453                 block++;
 454                 bh = bh->b_this_page;
 455         }
 456         page->index = index;
 457
 458         wait_event(bitmap->write_wait,
 459                    atomic_read(&bitmap->pending_writes)==0);
 460         if (bitmap->flags & BITMAP_WRITE_ERROR) {
 461                 free_buffers(page);
 462                 page = ERR_PTR(-EIO);
 463         }
 464 out:
 465         if (IS_ERR(page))
 466                 printk(KERN_ALERT "md: bitmap read error: (%dB @ %Lu): %ld\n",
 467                         (int)PAGE_SIZE,
 468                         (unsigned long long)index << PAGE_SHIFT,
 469                         PTR_ERR(page));
 470         return page;
 471 }
 472
 473 /*
 474  * bitmap file superblock operations
 475  */
 476
 477 /* update the event counter and sync the superblock to disk */
 478 void bitmap_update_sb(struct bitmap *bitmap)
 479 {
 480         bitmap_super_t *sb;
 481         unsigned long flags;
 482
 483         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
 484                 return;
 485         spin_lock_irqsave(&bitmap->lock, flags);
 486         if (!bitmap->sb_page) { /* no superblock */
 487                 spin_unlock_irqrestore(&bitmap->lock, flags);
 488                 return;
 489         }
 490         spin_unlock_irqrestore(&bitmap->lock, flags);
 491         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
 492         sb->events = cpu_to_le64(bitmap->mddev->events);
 493         if (bitmap->mddev->events < bitmap->events_cleared) {
 494                 /* rocking back to read-only */
 495                 bitmap->events_cleared = bitmap->mddev->events;
 496                 sb->events_cleared = cpu_to_le64(bitmap->events_cleared);
 497         }
 498         kunmap_atomic(sb, KM_USER0);
 499         write_page(bitmap, bitmap->sb_page, 1);
 500 }
 501
 502 /* print out the bitmap file superblock */
 503 void bitmap_print_sb(struct bitmap *bitmap)
 504 {
 505         bitmap_super_t *sb;
 506
 507         if (!bitmap || !bitmap->sb_page)
 508                 return;
 509         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
 510         printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
 511         printk(KERN_DEBUG "         magic: %08x\n", le32_to_cpu(sb->magic));
 512         printk(KERN_DEBUG "       version: %d\n", le32_to_cpu(sb->version));
 513         printk(KERN_DEBUG "          uuid: %08x.%08x.%08x.%08x\n",
 514                                         *(__u32 *)(sb->uuid+0),
 515                                         *(__u32 *)(sb->uuid+4),
 516                                         *(__u32 *)(sb->uuid+8),
 517                                         *(__u32 *)(sb->uuid+12));
 518         printk(KERN_DEBUG "        events: %llu\n",
 519                         (unsigned long long) le64_to_cpu(sb->events));
 520         printk(KERN_DEBUG "events cleared: %llu\n",
 521                         (unsigned long long) le64_to_cpu(sb->events_cleared));
 522         printk(KERN_DEBUG "         state: %08x\n", le32_to_cpu(sb->state));
 523         printk(KERN_DEBUG "     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
 524         printk(KERN_DEBUG "  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
 525         printk(KERN_DEBUG "     sync size: %llu KB\n",
 526                         (unsigned long long)le64_to_cpu(sb->sync_size)/2);
 527         printk(KERN_DEBUG "max write behind: %d\n", le32_to_cpu(sb->write_behind));
 528         kunmap_atomic(sb, KM_USER0);
 529 }
 530
 531 /* read the superblock from the bitmap file and initialize some bitmap fields */
 532 static int bitmap_read_sb(struct bitmap *bitmap)
 533 {
 534         char *reason = NULL;
 535         bitmap_super_t *sb;
 536         unsigned long chunksize, daemon_sleep, write_behind;
 537         unsigned long long events;
 538         int err = -EINVAL;
 539
 540         /* page 0 is the superblock, read it... */
 541         if (bitmap->file) {
 542                 loff_t isize = i_size_read(bitmap->file->f_mapping->host);
 543                 int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
 544
 545                 bitmap->sb_page = read_page(bitmap->file, 0, bitmap, bytes);
 546         } else {
 547                 bitmap->sb_page = read_sb_page(bitmap->mddev, bitmap->offset, 0);
 548         }
 549         if (IS_ERR(bitmap->sb_page)) {
 550                 err = PTR_ERR(bitmap->sb_page);
 551                 bitmap->sb_page = NULL;
 552                 return err;
 553         }
 554
 555         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
 556
 557         chunksize = le32_to_cpu(sb->chunksize);
 558         daemon_sleep = le32_to_cpu(sb->daemon_sleep);
 559         write_behind = le32_to_cpu(sb->write_behind);
 560
 561         /* verify that the bitmap-specific fields are valid */
 562         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
 563                 reason = "bad magic";
 564         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
 565                  le32_to_cpu(sb->version) > BITMAP_MAJOR_HI)
 566                 reason = "unrecognized superblock version";
 567         else if (chunksize < PAGE_SIZE)
 568                 reason = "bitmap chunksize too small";
 569         else if ((1 << ffz(~chunksize)) != chunksize)
 570                 reason = "bitmap chunksize not a power of 2";
 571         else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT / HZ)
 572                 reason = "daemon sleep period out of range";
 573         else if (write_behind > COUNTER_MAX)
 574                 reason = "write-behind limit out of range (0 - 16383)";
 575         if (reason) {
 576                 printk(KERN_INFO "%s: invalid bitmap file superblock: %s\n",
 577                         bmname(bitmap), reason);
 578                 goto out;
 579         }
 580
 581         /* keep the array size field of the bitmap superblock up to date */
 582         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 583
 584         if (!bitmap->mddev->persistent)
 585                 goto success;
 586
 587         /*
 588          * if we have a persistent array superblock, compare the
 589          * bitmap's UUID and event counter to the mddev's
 590          */
 591         if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
 592                 printk(KERN_INFO "%s: bitmap superblock UUID mismatch\n",
 593                         bmname(bitmap));
 594                 goto out;
 595         }
 596         events = le64_to_cpu(sb->events);
 597         if (events < bitmap->mddev->events) {
 598                 printk(KERN_INFO "%s: bitmap file is out of date (%llu < %llu) "
 599                         "-- forcing full recovery\n", bmname(bitmap), events,
 600                         (unsigned long long) bitmap->mddev->events);
 601                 sb->state |= cpu_to_le32(BITMAP_STALE);
 602         }
 603 success:
 604         /* assign fields using values from superblock */
 605         bitmap->chunksize = chunksize;
 606         bitmap->daemon_sleep = daemon_sleep;
 607         bitmap->daemon_lastrun = jiffies;
 608         bitmap->max_write_behind = write_behind;
 609         bitmap->flags |= le32_to_cpu(sb->state);
 610         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
 611                 bitmap->flags |= BITMAP_HOSTENDIAN;
 612         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
 613         if (sb->state & cpu_to_le32(BITMAP_STALE))
 614                 bitmap->events_cleared = bitmap->mddev->events;
 615         err = 0;
 616 out:
 617         kunmap_atomic(sb, KM_USER0);
 618         if (err)
 619                 bitmap_print_sb(bitmap);
 620         return err;
 621 }
 622
 623 enum bitmap_mask_op {
 624         MASK_SET,
 625         MASK_UNSET
 626 };
 627
 628 /* record the state of the bitmap in the superblock.  Return the old value */
 629 static int bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
 630                              enum bitmap_mask_op op)
 631 {
 632         bitmap_super_t *sb;
 633         unsigned long flags;
 634         int old;
 635
 636         spin_lock_irqsave(&bitmap->lock, flags);
 637         if (!bitmap->sb_page) { /* can't set the state */
 638                 spin_unlock_irqrestore(&bitmap->lock, flags);
 639                 return 0;
 640         }
 641         spin_unlock_irqrestore(&bitmap->lock, flags);
 642         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
 643         old = le32_to_cpu(sb->state) & bits;
 644         switch (op) {
 645                 case MASK_SET: sb->state |= cpu_to_le32(bits);
 646                                 break;
 647                 case MASK_UNSET: sb->state &= cpu_to_le32(~bits);
 648                                 break;
 649                 default: BUG();
 650         }
 651         kunmap_atomic(sb, KM_USER0);
 652         return old;
 653 }
 654
 655 /*
 656  * general bitmap file operations
 657  */
 658
 659 /* calculate the index of the page that contains this bit */
 660 static inline unsigned long file_page_index(unsigned long chunk)
 661 {
 662         return CHUNK_BIT_OFFSET(chunk) >> PAGE_BIT_SHIFT;
 663 }
 664
 665 /* calculate the (bit) offset of this bit within a page */
 666 static inline unsigned long file_page_offset(unsigned long chunk)
 667 {
 668         return CHUNK_BIT_OFFSET(chunk) & (PAGE_BITS - 1);
 669 }
 670
 671 /*
 672  * return a pointer to the page in the filemap that contains the given bit
 673  *
 674  * this lookup is complicated by the fact that the bitmap sb might be exactly
 675  * 1 page (e.g., x86) or less than 1 page -- so the bitmap might start on page
 676  * 0 or page 1
 677  */
 678 static inline struct page *filemap_get_page(struct bitmap *bitmap,
 679                                         unsigned long chunk)
 680 {
 681         if (file_page_index(chunk) >= bitmap->file_pages) return NULL;
 682         return bitmap->filemap[file_page_index(chunk) - file_page_index(0)];
 683 }
 684
 685
 686 static void bitmap_file_unmap(struct bitmap *bitmap)
 687 {
 688         struct page **map, *sb_page;
 689         unsigned long *attr;
 690         int pages;
 691         unsigned long flags;
 692
 693         spin_lock_irqsave(&bitmap->lock, flags);
 694         map = bitmap->filemap;
 695         bitmap->filemap = NULL;
 696         attr = bitmap->filemap_attr;
 697         bitmap->filemap_attr = NULL;
 698         pages = bitmap->file_pages;
 699         bitmap->file_pages = 0;
 700         sb_page = bitmap->sb_page;
 701         bitmap->sb_page = NULL;
 702         spin_unlock_irqrestore(&bitmap->lock, flags);
 703
 704         while (pages--)
 705                 if (map[pages]->index != 0) /* 0 is sb_page, release it below */
 706                         free_buffers(map[pages]);
 707         kfree(map);
 708         kfree(attr);
 709
 710         if (sb_page)
 711                 free_buffers(sb_page);
 712 }
 713
 714 static void bitmap_file_put(struct bitmap *bitmap)
 715 {
 716         struct file *file;
 717         unsigned long flags;
 718
 719         spin_lock_irqsave(&bitmap->lock, flags);
 720         file = bitmap->file;
 721         bitmap->file = NULL;
 722         spin_unlock_irqrestore(&bitmap->lock, flags);
 723
 724         if (file)
 725                 wait_event(bitmap->write_wait,
 726                            atomic_read(&bitmap->pending_writes)==0);
 727         bitmap_file_unmap(bitmap);
 728
 729         if (file) {
 730                 struct inode *inode = file->f_path.dentry->d_inode;
 731                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
 732                 fput(file);
 733         }
 734 }
 735
 736
 737 /*
 738  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
 739  * then it is no longer reliable, so we stop using it and we mark the file
 740  * as failed in the superblock
 741  */
 742 static void bitmap_file_kick(struct bitmap *bitmap)
 743 {
 744         char *path, *ptr = NULL;
 745
 746         if (bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET) == 0) {
 747                 bitmap_update_sb(bitmap);
 748
 749                 if (bitmap->file) {
 750                         path = kmalloc(PAGE_SIZE, GFP_KERNEL);
 751                         if (path)
 752                                 ptr = d_path(&bitmap->file->f_path, path,
 753                                              PAGE_SIZE);
 754
 755
 756                         printk(KERN_ALERT
 757                               "%s: kicking failed bitmap file %s from array!\n",
 758                               bmname(bitmap), IS_ERR(ptr) ? "" : ptr);
 759
 760                         kfree(path);
 761                 } else
 762                         printk(KERN_ALERT
 763                                "%s: disabling internal bitmap due to errors\n",
 764                                bmname(bitmap));
 765         }
 766
 767         bitmap_file_put(bitmap);
 768
 769         return;
 770 }
 771
 772 enum bitmap_page_attr {
 773         BITMAP_PAGE_DIRTY = 0, // there are set bits that need to be synced
 774         BITMAP_PAGE_CLEAN = 1, // there are bits that might need to be cleared
 775         BITMAP_PAGE_NEEDWRITE=2, // there are cleared bits that need to be synced
 776 };
 777
 778 static inline void set_page_attr(struct bitmap *bitmap, struct page *page,
 779                                 enum bitmap_page_attr attr)
 780 {
 781         __set_bit((page->index<<2) + attr, bitmap->filemap_attr);
 782 }
 783
 784 static inline void clear_page_attr(struct bitmap *bitmap, struct page *page,
 785                                 enum bitmap_page_attr attr)
 786 {
 787         __clear_bit((page->index<<2) + attr, bitmap->filemap_attr);
 788 }
 789
 790 static inline unsigned long test_page_attr(struct bitmap *bitmap, struct page *page,
 791                                            enum bitmap_page_attr attr)
 792 {
 793         return test_bit((page->index<<2) + attr, bitmap->filemap_attr);
 794 }
 795
 796 /*
 797  * bitmap_file_set_bit -- called before performing a write to the md device
 798  * to set (and eventually sync) a particular bit in the bitmap file
 799  *
 800  * we set the bit immediately, then we record the page number so that
 801  * when an unplug occurs, we can flush the dirty pages out to disk
 802  */
 803 static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 804 {
 805         unsigned long bit;
 806         struct page *page;
 807         void *kaddr;
 808         unsigned long chunk = block >> CHUNK_BLOCK_SHIFT(bitmap);
 809
 810         if (!bitmap->filemap) {
 811                 return;
 812         }
 813
 814         page = filemap_get_page(bitmap, chunk);
 815         if (!page) return;
 816         bit = file_page_offset(chunk);
 817
 818         /* set the bit */
 819         kaddr = kmap_atomic(page, KM_USER0);
 820         if (bitmap->flags & BITMAP_HOSTENDIAN)
 821                 set_bit(bit, kaddr);
 822         else
 823                 ext2_set_bit(bit, kaddr);
 824         kunmap_atomic(kaddr, KM_USER0);
 825         PRINTK("set file bit %lu page %lu\n", bit, page->index);
 826
 827         /* record page number so it gets flushed to disk when unplug occurs */
 828         set_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 829
 830 }
 831
 832 /* this gets called when the md device is ready to unplug its underlying
 833  * (slave) device queues -- before we let any writes go down, we need to
 834  * sync the dirty pages of the bitmap file to disk */
 835 void bitmap_unplug(struct bitmap *bitmap)
 836 {
 837         unsigned long i, flags;
 838         int dirty, need_write;
 839         struct page *page;
 840         int wait = 0;
 841
 842         if (!bitmap)
 843                 return;
 844
 845         /* look at each page to see if there are any set bits that need to be
 846          * flushed out to disk */
 847         for (i = 0; i < bitmap->file_pages; i++) {
 848                 spin_lock_irqsave(&bitmap->lock, flags);
 849                 if (!bitmap->filemap) {
 850                         spin_unlock_irqrestore(&bitmap->lock, flags);
 851                         return;
 852                 }
 853                 page = bitmap->filemap[i];
 854                 dirty = test_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 855                 need_write = test_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 856                 clear_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 857                 clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 858                 if (dirty)
 859                         wait = 1;
 860                 spin_unlock_irqrestore(&bitmap->lock, flags);
 861
 862                 if (dirty | need_write)
 863                         write_page(bitmap, page, 0);
 864         }
 865         if (wait) { /* if any writes were performed, we need to wait on them */
 866                 if (bitmap->file)
 867                         wait_event(bitmap->write_wait,
 868                                    atomic_read(&bitmap->pending_writes)==0);
 869                 else
 870                         md_super_wait(bitmap->mddev);
 871         }
 872         if (bitmap->flags & BITMAP_WRITE_ERROR)
 873                 bitmap_file_kick(bitmap);
 874 }
 875
 876 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
 877 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
 878  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
 879  * memory mapping of the bitmap file
 880  * Special cases:
 881  *   if there's no bitmap file, or if the bitmap file had been
 882  *   previously kicked from the array, we mark all the bits as
 883  *   1's in order to cause a full resync.
 884  *
 885  * We ignore all bits for sectors that end earlier than 'start'.
 886  * This is used when reading an out-of-date bitmap...
 887  */
 888 static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
 889 {
 890         unsigned long i, chunks, index, oldindex, bit;
 891         struct page *page = NULL, *oldpage = NULL;
 892         unsigned long num_pages, bit_cnt = 0;
 893         struct file *file;
 894         unsigned long bytes, offset;
 895         int outofdate;
 896         int ret = -ENOSPC;
 897         void *paddr;
 898
 899         chunks = bitmap->chunks;
 900         file = bitmap->file;
 901
 902         BUG_ON(!file && !bitmap->offset);
 903
 904 #ifdef INJECT_FAULTS_3
 905         outofdate = 1;
 906 #else
 907         outofdate = bitmap->flags & BITMAP_STALE;
 908 #endif
 909         if (outofdate)
 910                 printk(KERN_INFO "%s: bitmap file is out of date, doing full "
 911                         "recovery\n", bmname(bitmap));
 912
 913         bytes = (chunks + 7) / 8;
 914
 915         num_pages = (bytes + sizeof(bitmap_super_t) + PAGE_SIZE - 1) / PAGE_SIZE;
 916
 917         if (file && i_size_read(file->f_mapping->host) < bytes + sizeof(bitmap_super_t)) {
 918                 printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
 919                         bmname(bitmap),
 920                         (unsigned long) i_size_read(file->f_mapping->host),
 921                         bytes + sizeof(bitmap_super_t));
 922                 goto err;
 923         }
 924
 925         ret = -ENOMEM;
 926
 927         bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
 928         if (!bitmap->filemap)
 929                 goto err;
 930
 931         /* We need 4 bits per page, rounded up to a multiple of sizeof(unsigned long) */
 932         bitmap->filemap_attr = kzalloc(
 933                 roundup( DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
 934                 GFP_KERNEL);
 935         if (!bitmap->filemap_attr)
 936                 goto err;
 937
 938         oldindex = ~0L;
 939
 940         for (i = 0; i < chunks; i++) {
 941                 int b;
 942                 index = file_page_index(i);
 943                 bit = file_page_offset(i);
 944                 if (index != oldindex) { /* this is a new page, read it in */
 945                         int count;
 946                         /* unmap the old page, we're done with it */
 947                         if (index == num_pages-1)
 948                                 count = bytes + sizeof(bitmap_super_t)
 949                                         - index * PAGE_SIZE;
 950                         else
 951                                 count = PAGE_SIZE;
 952                         if (index == 0) {
 953                                 /*
 954                                  * if we're here then the superblock page
 955                                  * contains some bits (PAGE_SIZE != sizeof sb)
 956                                  * we've already read it in, so just use it
 957                                  */
 958                                 page = bitmap->sb_page;
 959                                 offset = sizeof(bitmap_super_t);
 960                         } else if (file) {
 961                                 page = read_page(file, index, bitmap, count);
 962                                 offset = 0;
 963                         } else {
 964                                 page = read_sb_page(bitmap->mddev, bitmap->offset, index);
 965                                 offset = 0;
 966                         }
 967                         if (IS_ERR(page)) { /* read error */
 968                                 ret = PTR_ERR(page);
 969                                 goto err;
 970                         }
 971
 972                         oldindex = index;
 973                         oldpage = page;
 974
 975                         if (outofdate) {
 976                                 /*
 977                                  * if bitmap is out of date, dirty the
 978                                  * whole page and write it out
 979                                  */
 980                                 paddr = kmap_atomic(page, KM_USER0);
 981                                 memset(paddr + offset, 0xff,
 982                                        PAGE_SIZE - offset);
 983                                 kunmap_atomic(paddr, KM_USER0);
 984                                 write_page(bitmap, page, 1);
 985
 986                                 ret = -EIO;
 987                                 if (bitmap->flags & BITMAP_WRITE_ERROR) {
 988                                         /* release, page not in filemap yet */
 989                                         put_page(page);
 990                                         goto err;
 991                                 }
 992                         }
 993
 994                         bitmap->filemap[bitmap->file_pages++] = page;
 995                         bitmap->last_page_size = count;
 996                 }
 997                 paddr = kmap_atomic(page, KM_USER0);
 998                 if (bitmap->flags & BITMAP_HOSTENDIAN)
 999                         b = test_bit(bit, paddr);
1000                 else
1001                         b = ext2_test_bit(bit, paddr);
1002                 kunmap_atomic(paddr, KM_USER0);
1003                 if (b) {
1004                         /* if the disk bit is set, set the memory bit */
1005                         bitmap_set_memory_bits(bitmap, i << CHUNK_BLOCK_SHIFT(bitmap),
1006                                                ((i+1) << (CHUNK_BLOCK_SHIFT(bitmap)) >= start)
1007                                 );
1008                         bit_cnt++;
1009                         set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1010                 }
1011         }
1012
1013         /* everything went OK */
1014         ret = 0;
1015         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_UNSET);
1016
1017         if (bit_cnt) { /* Kick recovery if any bits were set */
1018                 set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
1019                 md_wakeup_thread(bitmap->mddev->thread);
1020         }
1021
1022         printk(KERN_INFO "%s: bitmap initialized from disk: "
1023                 "read %lu/%lu pages, set %lu bits\n",
1024                 bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt);
1025
1026         return 0;
1027
1028  err:
1029         printk(KERN_INFO "%s: bitmap initialisation failed: %d\n",
1030                bmname(bitmap), ret);
1031         return ret;
1032 }
1033
1034 void bitmap_write_all(struct bitmap *bitmap)
1035 {
1036         /* We don't actually write all bitmap blocks here,
1037          * just flag them as needing to be written
1038          */
1039         int i;
1040
1041         for (i=0; i < bitmap->file_pages; i++)
1042                 set_page_attr(bitmap, bitmap->filemap[i],
1043                               BITMAP_PAGE_NEEDWRITE);
1044 }
1045
1046
1047 static void bitmap_count_page(struct bitmap *bitmap, sector_t offset, int inc)
1048 {
1049         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1050         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1051         bitmap->bp[page].count += inc;
1052 /*
1053         if (page == 0) printk("count page 0, offset %llu: %d gives %d\n",
1054                               (unsigned long long)offset, inc, bitmap->bp[page].count);
1055 */
1056         bitmap_checkfree(bitmap, page);
1057 }
1058 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1059                                             sector_t offset, int *blocks,
1060                                             int create);
1061
1062 /*
1063  * bitmap daemon -- periodically wakes up to clean bits and flush pages
1064  *                      out to disk
1065  */
1066
1067 void bitmap_daemon_work(struct bitmap *bitmap)
1068 {
1069         unsigned long j;
1070         unsigned long flags;
1071         struct page *page = NULL, *lastpage = NULL;
1072         int blocks;
1073         void *paddr;
1074
1075         if (bitmap == NULL)
1076                 return;
1077         if (time_before(jiffies, bitmap->daemon_lastrun + bitmap->daemon_sleep*HZ))
1078                 goto done;
1079
1080         bitmap->daemon_lastrun = jiffies;
1081         if (bitmap->allclean) {
1082                 bitmap->mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1083                 return;
1084         }
1085         bitmap->allclean = 1;
1086
1087         for (j = 0; j < bitmap->chunks; j++) {
1088                 bitmap_counter_t *bmc;
1089                 spin_lock_irqsave(&bitmap->lock, flags);
1090                 if (!bitmap->filemap) {
1091                         /* error or shutdown */
1092                         spin_unlock_irqrestore(&bitmap->lock, flags);
1093                         break;
1094                 }
1095
1096                 page = filemap_get_page(bitmap, j);
1097
1098                 if (page != lastpage) {
1099                         /* skip this page unless it's marked as needing cleaning */
1100                         if (!test_page_attr(bitmap, page, BITMAP_PAGE_CLEAN)) {
1101                                 int need_write = test_page_attr(bitmap, page,
1102                                                                 BITMAP_PAGE_NEEDWRITE);
1103                                 if (need_write)
1104                                         clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
1105
1106                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1107                                 if (need_write) {
1108                                         write_page(bitmap, page, 0);
1109                                         bitmap->allclean = 0;
1110                                 }
1111                                 continue;
1112                         }
1113
1114                         /* grab the new page, sync and release the old */
1115                         if (lastpage != NULL) {
1116                                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1117                                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1118                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1119                                         write_page(bitmap, lastpage, 0);
1120                                 } else {
1121                                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1122                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1123                                 }
1124                         } else
1125                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1126                         lastpage = page;
1127
1128                         /* We are possibly going to clear some bits, so make
1129                          * sure that events_cleared is up-to-date.
1130                          */
1131                         if (bitmap->need_sync) {
1132                                 bitmap_super_t *sb;
1133                                 bitmap->need_sync = 0;
1134                                 sb = kmap_atomic(bitmap->sb_page, KM_USER0);
1135                                 sb->events_cleared =
1136                                         cpu_to_le64(bitmap->events_cleared);
1137                                 kunmap_atomic(sb, KM_USER0);
1138                                 write_page(bitmap, bitmap->sb_page, 1);
1139                         }
1140                         spin_lock_irqsave(&bitmap->lock, flags);
1141                         clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1142                 }
1143                 bmc = bitmap_get_counter(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
1144                                         &blocks, 0);
1145                 if (bmc) {
1146 /*
1147   if (j < 100) printk("bitmap: j=%lu, *bmc = 0x%x\n", j, *bmc);
1148 */
1149                         if (*bmc)
1150                                 bitmap->allclean = 0;
1151
1152                         if (*bmc == 2) {
1153                                 *bmc=1; /* maybe clear the bit next time */
1154                                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1155                         } else if (*bmc == 1) {
1156                                 /* we can clear the bit */
1157                                 *bmc = 0;
1158                                 bitmap_count_page(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
1159                                                   -1);
1160
1161                                 /* clear the bit */
1162                                 paddr = kmap_atomic(page, KM_USER0);
1163                                 if (bitmap->flags & BITMAP_HOSTENDIAN)
1164                                         clear_bit(file_page_offset(j), paddr);
1165                                 else
1166                                         ext2_clear_bit(file_page_offset(j), paddr);
1167                                 kunmap_atomic(paddr, KM_USER0);
1168                         }
1169                 }
1170                 spin_unlock_irqrestore(&bitmap->lock, flags);
1171         }
1172
1173         /* now sync the final page */
1174         if (lastpage != NULL) {
1175                 spin_lock_irqsave(&bitmap->lock, flags);
1176                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1177                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1178                         spin_unlock_irqrestore(&bitmap->lock, flags);
1179                         write_page(bitmap, lastpage, 0);
1180                 } else {
1181                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1182                         spin_unlock_irqrestore(&bitmap->lock, flags);
1183                 }
1184         }
1185
1186  done:
1187         if (bitmap->allclean == 0)
1188                 bitmap->mddev->thread->timeout = bitmap->daemon_sleep * HZ;
1189 }
1190
1191 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1192                                             sector_t offset, int *blocks,
1193                                             int create)
1194 {
1195         /* If 'create', we might release the lock and reclaim it.
1196          * The lock must have been taken with interrupts enabled.
1197          * If !create, we don't release the lock.
1198          */
1199         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1200         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1201         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1202         sector_t csize;
1203
1204         if (bitmap_checkpage(bitmap, page, create) < 0) {
1205                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1206                 *blocks = csize - (offset & (csize- 1));
1207                 return NULL;
1208         }
1209         /* now locked ... */
1210
1211         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1212                 /* should we use the first or second counter field
1213                  * of the hijacked pointer? */
1214                 int hi = (pageoff > PAGE_COUNTER_MASK);
1215                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap) +
1216                                           PAGE_COUNTER_SHIFT - 1);
1217                 *blocks = csize - (offset & (csize- 1));
1218                 return  &((bitmap_counter_t *)
1219                           &bitmap->bp[page].map)[hi];
1220         } else { /* page is allocated */
1221                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1222                 *blocks = csize - (offset & (csize- 1));
1223                 return (bitmap_counter_t *)
1224                         &(bitmap->bp[page].map[pageoff]);
1225         }
1226 }
1227
1228 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1229 {
1230         if (!bitmap) return 0;
1231
1232         if (behind) {
1233                 atomic_inc(&bitmap->behind_writes);
1234                 PRINTK(KERN_DEBUG "inc write-behind count %d/%d\n",
1235                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1236         }
1237
1238         while (sectors) {
1239                 int blocks;
1240                 bitmap_counter_t *bmc;
1241
1242                 spin_lock_irq(&bitmap->lock);
1243                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 1);
1244                 if (!bmc) {
1245                         spin_unlock_irq(&bitmap->lock);
1246                         return 0;
1247                 }
1248
1249                 if (unlikely((*bmc & COUNTER_MAX) == COUNTER_MAX)) {
1250                         DEFINE_WAIT(__wait);
1251                         /* note that it is safe to do the prepare_to_wait
1252                          * after the test as long as we do it before dropping
1253                          * the spinlock.
1254                          */
1255                         prepare_to_wait(&bitmap->overflow_wait, &__wait,
1256                                         TASK_UNINTERRUPTIBLE);
1257                         spin_unlock_irq(&bitmap->lock);
1258                         blk_unplug(bitmap->mddev->queue);
1259                         schedule();
1260                         finish_wait(&bitmap->overflow_wait, &__wait);
1261                         continue;
1262                 }
1263
1264                 switch(*bmc) {
1265                 case 0:
1266                         bitmap_file_set_bit(bitmap, offset);
1267                         bitmap_count_page(bitmap,offset, 1);
1268                         blk_plug_device_unlocked(bitmap->mddev->queue);
1269                         /* fall through */
1270                 case 1:
1271                         *bmc = 2;
1272                 }
1273
1274                 (*bmc)++;
1275
1276                 spin_unlock_irq(&bitmap->lock);
1277
1278                 offset += blocks;
1279                 if (sectors > blocks)
1280                         sectors -= blocks;
1281                 else sectors = 0;
1282         }
1283         bitmap->allclean = 0;
1284         return 0;
1285 }
1286
1287 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1288                      int success, int behind)
1289 {
1290         if (!bitmap) return;
1291         if (behind) {
1292                 atomic_dec(&bitmap->behind_writes);
1293                 PRINTK(KERN_DEBUG "dec write-behind count %d/%d\n",
1294                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1295         }
1296
1297         while (sectors) {
1298                 int blocks;
1299                 unsigned long flags;
1300                 bitmap_counter_t *bmc;
1301
1302                 spin_lock_irqsave(&bitmap->lock, flags);
1303                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 0);
1304                 if (!bmc) {
1305                         spin_unlock_irqrestore(&bitmap->lock, flags);
1306                         return;
1307                 }
1308
1309                 if (success &&
1310                     bitmap->events_cleared < bitmap->mddev->events) {
1311                         bitmap->events_cleared = bitmap->mddev->events;
1312                         bitmap->need_sync = 1;
1313                 }
1314
1315                 if (!success && ! (*bmc & NEEDED_MASK))
1316                         *bmc |= NEEDED_MASK;
1317
1318                 if ((*bmc & COUNTER_MAX) == COUNTER_MAX)
1319                         wake_up(&bitmap->overflow_wait);
1320
1321                 (*bmc)--;
1322                 if (*bmc <= 2) {
1323                         set_page_attr(bitmap,
1324                                       filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1325                                       BITMAP_PAGE_CLEAN);
1326                 }
1327                 spin_unlock_irqrestore(&bitmap->lock, flags);
1328                 offset += blocks;
1329                 if (sectors > blocks)
1330                         sectors -= blocks;
1331                 else sectors = 0;
1332         }
1333 }
1334
1335 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
1336                         int degraded)
1337 {
1338         bitmap_counter_t *bmc;
1339         int rv;
1340         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1341                 *blocks = 1024;
1342                 return 1; /* always resync if no bitmap */
1343         }
1344         spin_lock_irq(&bitmap->lock);
1345         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1346         rv = 0;
1347         if (bmc) {
1348                 /* locked */
1349                 if (RESYNC(*bmc))
1350                         rv = 1;
1351                 else if (NEEDED(*bmc)) {
1352                         rv = 1;
1353                         if (!degraded) { /* don't set/clear bits if degraded */
1354                                 *bmc |= RESYNC_MASK;
1355                                 *bmc &= ~NEEDED_MASK;
1356                         }
1357                 }
1358         }
1359         spin_unlock_irq(&bitmap->lock);
1360         bitmap->allclean = 0;
1361         return rv;
1362 }
1363
1364 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int aborted)
1365 {
1366         bitmap_counter_t *bmc;
1367         unsigned long flags;
1368 /*
1369         if (offset == 0) printk("bitmap_end_sync 0 (%d)\n", aborted);
1370 */      if (bitmap == NULL) {
1371                 *blocks = 1024;
1372                 return;
1373         }
1374         spin_lock_irqsave(&bitmap->lock, flags);
1375         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1376         if (bmc == NULL)
1377                 goto unlock;
1378         /* locked */
1379 /*
1380         if (offset == 0) printk("bitmap_end sync found 0x%x, blocks %d\n", *bmc, *blocks);
1381 */
1382         if (RESYNC(*bmc)) {
1383                 *bmc &= ~RESYNC_MASK;
1384
1385                 if (!NEEDED(*bmc) && aborted)
1386                         *bmc |= NEEDED_MASK;
1387                 else {
1388                         if (*bmc <= 2) {
1389                                 set_page_attr(bitmap,
1390                                               filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1391                                               BITMAP_PAGE_CLEAN);
1392                         }
1393                 }
1394         }
1395  unlock:
1396         spin_unlock_irqrestore(&bitmap->lock, flags);
1397         bitmap->allclean = 0;
1398 }
1399
1400 void bitmap_close_sync(struct bitmap *bitmap)
1401 {
1402         /* Sync has finished, and any bitmap chunks that weren't synced
1403          * properly have been aborted.  It remains to us to clear the
1404          * RESYNC bit wherever it is still on
1405          */
1406         sector_t sector = 0;
1407         int blocks;
1408         if (!bitmap)
1409                 return;
1410         while (sector < bitmap->mddev->resync_max_sectors) {
1411                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1412                 sector += blocks;
1413         }
1414 }
1415
1416 void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector)
1417 {
1418         sector_t s = 0;
1419         int blocks;
1420
1421         if (!bitmap)
1422                 return;
1423         if (sector == 0) {
1424                 bitmap->last_end_sync = jiffies;
1425                 return;
1426         }
1427         if (time_before(jiffies, (bitmap->last_end_sync
1428                                   + bitmap->daemon_sleep * HZ)))
1429                 return;
1430         wait_event(bitmap->mddev->recovery_wait,
1431                    atomic_read(&bitmap->mddev->recovery_active) == 0);
1432
1433         sector &= ~((1ULL << CHUNK_BLOCK_SHIFT(bitmap)) - 1);
1434         s = 0;
1435         while (s < sector && s < bitmap->mddev->resync_max_sectors) {
1436                 bitmap_end_sync(bitmap, s, &blocks, 0);
1437                 s += blocks;
1438         }
1439         bitmap->last_end_sync = jiffies;
1440 }
1441
1442 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1443 {
1444         /* For each chunk covered by any of these sectors, set the
1445          * counter to 1 and set resync_needed.  They should all
1446          * be 0 at this point
1447          */
1448
1449         int secs;
1450         bitmap_counter_t *bmc;
1451         spin_lock_irq(&bitmap->lock);
1452         bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
1453         if (!bmc) {
1454                 spin_unlock_irq(&bitmap->lock);
1455                 return;
1456         }
1457         if (! *bmc) {
1458                 struct page *page;
1459                 *bmc = 1 | (needed?NEEDED_MASK:0);
1460                 bitmap_count_page(bitmap, offset, 1);
1461                 page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));
1462                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1463         }
1464         spin_unlock_irq(&bitmap->lock);
1465         bitmap->allclean = 0;
1466 }
1467
1468 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
1469 void bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1470 {
1471         unsigned long chunk;
1472
1473         for (chunk = s; chunk <= e; chunk++) {
1474                 sector_t sec = chunk << CHUNK_BLOCK_SHIFT(bitmap);
1475                 bitmap_set_memory_bits(bitmap, sec, 1);
1476                 bitmap_file_set_bit(bitmap, sec);
1477         }
1478 }
1479
1480 /*
1481  * flush out any pending updates
1482  */
1483 void bitmap_flush(mddev_t *mddev)
1484 {
1485         struct bitmap *bitmap = mddev->bitmap;
1486         int sleep;
1487
1488         if (!bitmap) /* there was no bitmap */
1489                 return;
1490
1491         /* run the daemon_work three time to ensure everything is flushed
1492          * that can be
1493          */
1494         sleep = bitmap->daemon_sleep;
1495         bitmap->daemon_sleep = 0;
1496         bitmap_daemon_work(bitmap);
1497         bitmap_daemon_work(bitmap);
1498         bitmap_daemon_work(bitmap);
1499         bitmap->daemon_sleep = sleep;
1500         bitmap_update_sb(bitmap);
1501 }
1502
1503 /*
1504  * free memory that was allocated
1505  */
1506 static void bitmap_free(struct bitmap *bitmap)
1507 {
1508         unsigned long k, pages;
1509         struct bitmap_page *bp;
1510
1511         if (!bitmap) /* there was no bitmap */
1512                 return;
1513
1514         /* release the bitmap file and kill the daemon */
1515         bitmap_file_put(bitmap);
1516
1517         bp = bitmap->bp;
1518         pages = bitmap->pages;
1519
1520         /* free all allocated memory */
1521
1522         if (bp) /* deallocate the page memory */
1523                 for (k = 0; k < pages; k++)
1524                         if (bp[k].map && !bp[k].hijacked)
1525                                 kfree(bp[k].map);
1526         kfree(bp);
1527         kfree(bitmap);
1528 }
1529 void bitmap_destroy(mddev_t *mddev)
1530 {
1531         struct bitmap *bitmap = mddev->bitmap;
1532
1533         if (!bitmap) /* there was no bitmap */
1534                 return;
1535
1536         mddev->bitmap = NULL; /* disconnect from the md device */
1537         if (mddev->thread)
1538                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1539
1540         bitmap_free(bitmap);
1541 }
1542
1543 /*
1544  * initialize the bitmap structure
1545  * if this returns an error, bitmap_destroy must be called to do clean up
1546  */
1547 int bitmap_create(mddev_t *mddev)
1548 {
1549         struct bitmap *bitmap;
1550         unsigned long blocks = mddev->resync_max_sectors;
1551         unsigned long chunks;
1552         unsigned long pages;
1553         struct file *file = mddev->bitmap_file;
1554         int err;
1555         sector_t start;
1556
1557         BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
1558
1559         if (!file && !mddev->bitmap_offset) /* bitmap disabled, nothing to do */
1560                 return 0;
1561
1562         BUG_ON(file && mddev->bitmap_offset);
1563
1564         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1565         if (!bitmap)
1566                 return -ENOMEM;
1567
1568         spin_lock_init(&bitmap->lock);
1569         atomic_set(&bitmap->pending_writes, 0);
1570         init_waitqueue_head(&bitmap->write_wait);
1571         init_waitqueue_head(&bitmap->overflow_wait);
1572
1573         bitmap->mddev = mddev;
1574
1575         bitmap->file = file;
1576         bitmap->offset = mddev->bitmap_offset;
1577         if (file) {
1578                 get_file(file);
1579                 do_sync_mapping_range(file->f_mapping, 0, LLONG_MAX,
1580                                       SYNC_FILE_RANGE_WAIT_BEFORE |
1581                                       SYNC_FILE_RANGE_WRITE |
1582                                       SYNC_FILE_RANGE_WAIT_AFTER);
1583         }
1584         /* read superblock from bitmap file (this sets bitmap->chunksize) */
1585         err = bitmap_read_sb(bitmap);
1586         if (err)
1587                 goto error;
1588
1589         bitmap->chunkshift = ffz(~bitmap->chunksize);
1590
1591         /* now that chunksize and chunkshift are set, we can use these macros */
1592         chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) /
1593                         CHUNK_BLOCK_RATIO(bitmap);
1594         pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
1595
1596         BUG_ON(!pages);
1597
1598         bitmap->chunks = chunks;
1599         bitmap->pages = pages;
1600         bitmap->missing_pages = pages;
1601         bitmap->counter_bits = COUNTER_BITS;
1602
1603         bitmap->syncchunk = ~0UL;
1604
1605 #ifdef INJECT_FATAL_FAULT_1
1606         bitmap->bp = NULL;
1607 #else
1608         bitmap->bp = kzalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
1609 #endif
1610         err = -ENOMEM;
1611         if (!bitmap->bp)
1612                 goto error;
1613
1614         /* now that we have some pages available, initialize the in-memory
1615          * bitmap from the on-disk bitmap */
1616         start = 0;
1617         if (mddev->degraded == 0
1618             || bitmap->events_cleared == mddev->events)
1619                 /* no need to keep dirty bits to optimise a re-add of a missing device */
1620                 start = mddev->recovery_cp;
1621         err = bitmap_init_from_disk(bitmap, start);
1622
1623         if (err)
1624                 goto error;
1625
1626         printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
1627                 pages, bmname(bitmap));
1628
1629         mddev->bitmap = bitmap;
1630
1631         mddev->thread->timeout = bitmap->daemon_sleep * HZ;
1632
1633         bitmap_update_sb(bitmap);
1634
1635         return (bitmap->flags & BITMAP_WRITE_ERROR) ? -EIO : 0;
1636
1637  error:
1638         bitmap_free(bitmap);
1639         return err;
1640 }
1641
1642 /* the bitmap API -- for raid personalities */
1643 EXPORT_SYMBOL(bitmap_startwrite);
1644 EXPORT_SYMBOL(bitmap_endwrite);
1645 EXPORT_SYMBOL(bitmap_start_sync);
1646 EXPORT_SYMBOL(bitmap_end_sync);
1647 EXPORT_SYMBOL(bitmap_unplug);
1648 EXPORT_SYMBOL(bitmap_close_sync);
1649 EXPORT_SYMBOL(bitmap_cond_end_sync);