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