git.oblomov.eu Git - linux-2.6/blob - drivers/md/bitmap.c

   1 /*
   2  * bitmap.c two-level bitmap (C) Peter T. Breuer (ptb@ot.uc3m.es) 2003
   3  *
   4  * bitmap_create  - sets up the bitmap structure
   5  * bitmap_destroy - destroys the bitmap structure
   6  *
   7  * additions, Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.:
   8  * - added disk storage for bitmap
   9  * - changes to allow various bitmap chunk sizes
  10  */
  11
  12 /*
  13  * Still to do:
  14  *
  15  * flush after percent set rather than just time based. (maybe both).
  16  * wait if count gets too high, wake when it drops to half.
  17  */
  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 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_start + bitmap->offset)
 266                                         /* data runs in to bitmap */
 267                                         return -EINVAL;
 268                         } else if (rdev->sb_start < rdev->data_offset) {
 269                                 /* METADATA BITMAP DATA */
 270                                 if (rdev->sb_start
 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_start + 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->events < bitmap->events_cleared) {
 458                 /* rocking back to read-only */
 459                 bitmap->events_cleared = bitmap->mddev->events;
 460                 sb->events_cleared = cpu_to_le64(bitmap->events_cleared);
 461         }
 462         kunmap_atomic(sb, KM_USER0);
 463         write_page(bitmap, bitmap->sb_page, 1);
 464 }
 465
 466 /* print out the bitmap file superblock */
 467 void bitmap_print_sb(struct bitmap *bitmap)
 468 {
 469         bitmap_super_t *sb;
 470
 471         if (!bitmap || !bitmap->sb_page)
 472                 return;
 473         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
 474         printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
 475         printk(KERN_DEBUG "         magic: %08x\n", le32_to_cpu(sb->magic));
 476         printk(KERN_DEBUG "       version: %d\n", le32_to_cpu(sb->version));
 477         printk(KERN_DEBUG "          uuid: %08x.%08x.%08x.%08x\n",
 478                                         *(__u32 *)(sb->uuid+0),
 479                                         *(__u32 *)(sb->uuid+4),
 480                                         *(__u32 *)(sb->uuid+8),
 481                                         *(__u32 *)(sb->uuid+12));
 482         printk(KERN_DEBUG "        events: %llu\n",
 483                         (unsigned long long) le64_to_cpu(sb->events));
 484         printk(KERN_DEBUG "events cleared: %llu\n",
 485                         (unsigned long long) le64_to_cpu(sb->events_cleared));
 486         printk(KERN_DEBUG "         state: %08x\n", le32_to_cpu(sb->state));
 487         printk(KERN_DEBUG "     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
 488         printk(KERN_DEBUG "  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
 489         printk(KERN_DEBUG "     sync size: %llu KB\n",
 490                         (unsigned long long)le64_to_cpu(sb->sync_size)/2);
 491         printk(KERN_DEBUG "max write behind: %d\n", le32_to_cpu(sb->write_behind));
 492         kunmap_atomic(sb, KM_USER0);
 493 }
 494
 495 /* read the superblock from the bitmap file and initialize some bitmap fields */
 496 static int bitmap_read_sb(struct bitmap *bitmap)
 497 {
 498         char *reason = NULL;
 499         bitmap_super_t *sb;
 500         unsigned long chunksize, daemon_sleep, write_behind;
 501         unsigned long long events;
 502         int err = -EINVAL;
 503
 504         /* page 0 is the superblock, read it... */
 505         if (bitmap->file) {
 506                 loff_t isize = i_size_read(bitmap->file->f_mapping->host);
 507                 int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
 508
 509                 bitmap->sb_page = read_page(bitmap->file, 0, bitmap, bytes);
 510         } else {
 511                 bitmap->sb_page = read_sb_page(bitmap->mddev, bitmap->offset, 0);
 512         }
 513         if (IS_ERR(bitmap->sb_page)) {
 514                 err = PTR_ERR(bitmap->sb_page);
 515                 bitmap->sb_page = NULL;
 516                 return err;
 517         }
 518
 519         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
 520
 521         chunksize = le32_to_cpu(sb->chunksize);
 522         daemon_sleep = le32_to_cpu(sb->daemon_sleep);
 523         write_behind = le32_to_cpu(sb->write_behind);
 524
 525         /* verify that the bitmap-specific fields are valid */
 526         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
 527                 reason = "bad magic";
 528         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
 529                  le32_to_cpu(sb->version) > BITMAP_MAJOR_HI)
 530                 reason = "unrecognized superblock version";
 531         else if (chunksize < PAGE_SIZE)
 532                 reason = "bitmap chunksize too small";
 533         else if ((1 << ffz(~chunksize)) != chunksize)
 534                 reason = "bitmap chunksize not a power of 2";
 535         else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT / HZ)
 536                 reason = "daemon sleep period out of range";
 537         else if (write_behind > COUNTER_MAX)
 538                 reason = "write-behind limit out of range (0 - 16383)";
 539         if (reason) {
 540                 printk(KERN_INFO "%s: invalid bitmap file superblock: %s\n",
 541                         bmname(bitmap), reason);
 542                 goto out;
 543         }
 544
 545         /* keep the array size field of the bitmap superblock up to date */
 546         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 547
 548         if (!bitmap->mddev->persistent)
 549                 goto success;
 550
 551         /*
 552          * if we have a persistent array superblock, compare the
 553          * bitmap's UUID and event counter to the mddev's
 554          */
 555         if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
 556                 printk(KERN_INFO "%s: bitmap superblock UUID mismatch\n",
 557                         bmname(bitmap));
 558                 goto out;
 559         }
 560         events = le64_to_cpu(sb->events);
 561         if (events < bitmap->mddev->events) {
 562                 printk(KERN_INFO "%s: bitmap file is out of date (%llu < %llu) "
 563                         "-- forcing full recovery\n", bmname(bitmap), events,
 564                         (unsigned long long) bitmap->mddev->events);
 565                 sb->state |= cpu_to_le32(BITMAP_STALE);
 566         }
 567 success:
 568         /* assign fields using values from superblock */
 569         bitmap->chunksize = chunksize;
 570         bitmap->daemon_sleep = daemon_sleep;
 571         bitmap->daemon_lastrun = jiffies;
 572         bitmap->max_write_behind = write_behind;
 573         bitmap->flags |= le32_to_cpu(sb->state);
 574         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
 575                 bitmap->flags |= BITMAP_HOSTENDIAN;
 576         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
 577         if (sb->state & cpu_to_le32(BITMAP_STALE))
 578                 bitmap->events_cleared = bitmap->mddev->events;
 579         err = 0;
 580 out:
 581         kunmap_atomic(sb, KM_USER0);
 582         if (err)
 583                 bitmap_print_sb(bitmap);
 584         return err;
 585 }
 586
 587 enum bitmap_mask_op {
 588         MASK_SET,
 589         MASK_UNSET
 590 };
 591
 592 /* record the state of the bitmap in the superblock.  Return the old value */
 593 static int bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
 594                              enum bitmap_mask_op op)
 595 {
 596         bitmap_super_t *sb;
 597         unsigned long flags;
 598         int old;
 599
 600         spin_lock_irqsave(&bitmap->lock, flags);
 601         if (!bitmap->sb_page) { /* can't set the state */
 602                 spin_unlock_irqrestore(&bitmap->lock, flags);
 603                 return 0;
 604         }
 605         spin_unlock_irqrestore(&bitmap->lock, flags);
 606         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
 607         old = le32_to_cpu(sb->state) & bits;
 608         switch (op) {
 609                 case MASK_SET: sb->state |= cpu_to_le32(bits);
 610                                 break;
 611                 case MASK_UNSET: sb->state &= cpu_to_le32(~bits);
 612                                 break;
 613                 default: BUG();
 614         }
 615         kunmap_atomic(sb, KM_USER0);
 616         return old;
 617 }
 618
 619 /*
 620  * general bitmap file operations
 621  */
 622
 623 /* calculate the index of the page that contains this bit */
 624 static inline unsigned long file_page_index(unsigned long chunk)
 625 {
 626         return CHUNK_BIT_OFFSET(chunk) >> PAGE_BIT_SHIFT;
 627 }
 628
 629 /* calculate the (bit) offset of this bit within a page */
 630 static inline unsigned long file_page_offset(unsigned long chunk)
 631 {
 632         return CHUNK_BIT_OFFSET(chunk) & (PAGE_BITS - 1);
 633 }
 634
 635 /*
 636  * return a pointer to the page in the filemap that contains the given bit
 637  *
 638  * this lookup is complicated by the fact that the bitmap sb might be exactly
 639  * 1 page (e.g., x86) or less than 1 page -- so the bitmap might start on page
 640  * 0 or page 1
 641  */
 642 static inline struct page *filemap_get_page(struct bitmap *bitmap,
 643                                         unsigned long chunk)
 644 {
 645         if (file_page_index(chunk) >= bitmap->file_pages) return NULL;
 646         return bitmap->filemap[file_page_index(chunk) - file_page_index(0)];
 647 }
 648
 649
 650 static void bitmap_file_unmap(struct bitmap *bitmap)
 651 {
 652         struct page **map, *sb_page;
 653         unsigned long *attr;
 654         int pages;
 655         unsigned long flags;
 656
 657         spin_lock_irqsave(&bitmap->lock, flags);
 658         map = bitmap->filemap;
 659         bitmap->filemap = NULL;
 660         attr = bitmap->filemap_attr;
 661         bitmap->filemap_attr = NULL;
 662         pages = bitmap->file_pages;
 663         bitmap->file_pages = 0;
 664         sb_page = bitmap->sb_page;
 665         bitmap->sb_page = NULL;
 666         spin_unlock_irqrestore(&bitmap->lock, flags);
 667
 668         while (pages--)
 669                 if (map[pages]->index != 0) /* 0 is sb_page, release it below */
 670                         free_buffers(map[pages]);
 671         kfree(map);
 672         kfree(attr);
 673
 674         if (sb_page)
 675                 free_buffers(sb_page);
 676 }
 677
 678 static void bitmap_file_put(struct bitmap *bitmap)
 679 {
 680         struct file *file;
 681         unsigned long flags;
 682
 683         spin_lock_irqsave(&bitmap->lock, flags);
 684         file = bitmap->file;
 685         bitmap->file = NULL;
 686         spin_unlock_irqrestore(&bitmap->lock, flags);
 687
 688         if (file)
 689                 wait_event(bitmap->write_wait,
 690                            atomic_read(&bitmap->pending_writes)==0);
 691         bitmap_file_unmap(bitmap);
 692
 693         if (file) {
 694                 struct inode *inode = file->f_path.dentry->d_inode;
 695                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
 696                 fput(file);
 697         }
 698 }
 699
 700
 701 /*
 702  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
 703  * then it is no longer reliable, so we stop using it and we mark the file
 704  * as failed in the superblock
 705  */
 706 static void bitmap_file_kick(struct bitmap *bitmap)
 707 {
 708         char *path, *ptr = NULL;
 709
 710         if (bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET) == 0) {
 711                 bitmap_update_sb(bitmap);
 712
 713                 if (bitmap->file) {
 714                         path = kmalloc(PAGE_SIZE, GFP_KERNEL);
 715                         if (path)
 716                                 ptr = d_path(&bitmap->file->f_path, path,
 717                                              PAGE_SIZE);
 718
 719
 720                         printk(KERN_ALERT
 721                               "%s: kicking failed bitmap file %s from array!\n",
 722                               bmname(bitmap), IS_ERR(ptr) ? "" : ptr);
 723
 724                         kfree(path);
 725                 } else
 726                         printk(KERN_ALERT
 727                                "%s: disabling internal bitmap due to errors\n",
 728                                bmname(bitmap));
 729         }
 730
 731         bitmap_file_put(bitmap);
 732
 733         return;
 734 }
 735
 736 enum bitmap_page_attr {
 737         BITMAP_PAGE_DIRTY = 0, // there are set bits that need to be synced
 738         BITMAP_PAGE_CLEAN = 1, // there are bits that might need to be cleared
 739         BITMAP_PAGE_NEEDWRITE=2, // there are cleared bits that need to be synced
 740 };
 741
 742 static inline void set_page_attr(struct bitmap *bitmap, struct page *page,
 743                                 enum bitmap_page_attr attr)
 744 {
 745         __set_bit((page->index<<2) + attr, bitmap->filemap_attr);
 746 }
 747
 748 static inline void clear_page_attr(struct bitmap *bitmap, struct page *page,
 749                                 enum bitmap_page_attr attr)
 750 {
 751         __clear_bit((page->index<<2) + attr, bitmap->filemap_attr);
 752 }
 753
 754 static inline unsigned long test_page_attr(struct bitmap *bitmap, struct page *page,
 755                                            enum bitmap_page_attr attr)
 756 {
 757         return test_bit((page->index<<2) + attr, bitmap->filemap_attr);
 758 }
 759
 760 /*
 761  * bitmap_file_set_bit -- called before performing a write to the md device
 762  * to set (and eventually sync) a particular bit in the bitmap file
 763  *
 764  * we set the bit immediately, then we record the page number so that
 765  * when an unplug occurs, we can flush the dirty pages out to disk
 766  */
 767 static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 768 {
 769         unsigned long bit;
 770         struct page *page;
 771         void *kaddr;
 772         unsigned long chunk = block >> CHUNK_BLOCK_SHIFT(bitmap);
 773
 774         if (!bitmap->filemap) {
 775                 return;
 776         }
 777
 778         page = filemap_get_page(bitmap, chunk);
 779         if (!page) return;
 780         bit = file_page_offset(chunk);
 781
 782         /* set the bit */
 783         kaddr = kmap_atomic(page, KM_USER0);
 784         if (bitmap->flags & BITMAP_HOSTENDIAN)
 785                 set_bit(bit, kaddr);
 786         else
 787                 ext2_set_bit(bit, kaddr);
 788         kunmap_atomic(kaddr, KM_USER0);
 789         PRINTK("set file bit %lu page %lu\n", bit, page->index);
 790
 791         /* record page number so it gets flushed to disk when unplug occurs */
 792         set_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 793
 794 }
 795
 796 /* this gets called when the md device is ready to unplug its underlying
 797  * (slave) device queues -- before we let any writes go down, we need to
 798  * sync the dirty pages of the bitmap file to disk */
 799 void bitmap_unplug(struct bitmap *bitmap)
 800 {
 801         unsigned long i, flags;
 802         int dirty, need_write;
 803         struct page *page;
 804         int wait = 0;
 805
 806         if (!bitmap)
 807                 return;
 808
 809         /* look at each page to see if there are any set bits that need to be
 810          * flushed out to disk */
 811         for (i = 0; i < bitmap->file_pages; i++) {
 812                 spin_lock_irqsave(&bitmap->lock, flags);
 813                 if (!bitmap->filemap) {
 814                         spin_unlock_irqrestore(&bitmap->lock, flags);
 815                         return;
 816                 }
 817                 page = bitmap->filemap[i];
 818                 dirty = test_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 819                 need_write = test_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 820                 clear_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 821                 clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 822                 if (dirty)
 823                         wait = 1;
 824                 spin_unlock_irqrestore(&bitmap->lock, flags);
 825
 826                 if (dirty | need_write)
 827                         write_page(bitmap, page, 0);
 828         }
 829         if (wait) { /* if any writes were performed, we need to wait on them */
 830                 if (bitmap->file)
 831                         wait_event(bitmap->write_wait,
 832                                    atomic_read(&bitmap->pending_writes)==0);
 833                 else
 834                         md_super_wait(bitmap->mddev);
 835         }
 836         if (bitmap->flags & BITMAP_WRITE_ERROR)
 837                 bitmap_file_kick(bitmap);
 838 }
 839
 840 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
 841 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
 842  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
 843  * memory mapping of the bitmap file
 844  * Special cases:
 845  *   if there's no bitmap file, or if the bitmap file had been
 846  *   previously kicked from the array, we mark all the bits as
 847  *   1's in order to cause a full resync.
 848  *
 849  * We ignore all bits for sectors that end earlier than 'start'.
 850  * This is used when reading an out-of-date bitmap...
 851  */
 852 static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
 853 {
 854         unsigned long i, chunks, index, oldindex, bit;
 855         struct page *page = NULL, *oldpage = NULL;
 856         unsigned long num_pages, bit_cnt = 0;
 857         struct file *file;
 858         unsigned long bytes, offset;
 859         int outofdate;
 860         int ret = -ENOSPC;
 861         void *paddr;
 862
 863         chunks = bitmap->chunks;
 864         file = bitmap->file;
 865
 866         BUG_ON(!file && !bitmap->offset);
 867
 868 #ifdef INJECT_FAULTS_3
 869         outofdate = 1;
 870 #else
 871         outofdate = bitmap->flags & BITMAP_STALE;
 872 #endif
 873         if (outofdate)
 874                 printk(KERN_INFO "%s: bitmap file is out of date, doing full "
 875                         "recovery\n", bmname(bitmap));
 876
 877         bytes = (chunks + 7) / 8;
 878
 879         num_pages = (bytes + sizeof(bitmap_super_t) + PAGE_SIZE - 1) / PAGE_SIZE;
 880
 881         if (file && i_size_read(file->f_mapping->host) < bytes + sizeof(bitmap_super_t)) {
 882                 printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
 883                         bmname(bitmap),
 884                         (unsigned long) i_size_read(file->f_mapping->host),
 885                         bytes + sizeof(bitmap_super_t));
 886                 goto err;
 887         }
 888
 889         ret = -ENOMEM;
 890
 891         bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
 892         if (!bitmap->filemap)
 893                 goto err;
 894
 895         /* We need 4 bits per page, rounded up to a multiple of sizeof(unsigned long) */
 896         bitmap->filemap_attr = kzalloc(
 897                 roundup( DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
 898                 GFP_KERNEL);
 899         if (!bitmap->filemap_attr)
 900                 goto err;
 901
 902         oldindex = ~0L;
 903
 904         for (i = 0; i < chunks; i++) {
 905                 int b;
 906                 index = file_page_index(i);
 907                 bit = file_page_offset(i);
 908                 if (index != oldindex) { /* this is a new page, read it in */
 909                         int count;
 910                         /* unmap the old page, we're done with it */
 911                         if (index == num_pages-1)
 912                                 count = bytes + sizeof(bitmap_super_t)
 913                                         - index * PAGE_SIZE;
 914                         else
 915                                 count = PAGE_SIZE;
 916                         if (index == 0) {
 917                                 /*
 918                                  * if we're here then the superblock page
 919                                  * contains some bits (PAGE_SIZE != sizeof sb)
 920                                  * we've already read it in, so just use it
 921                                  */
 922                                 page = bitmap->sb_page;
 923                                 offset = sizeof(bitmap_super_t);
 924                         } else if (file) {
 925                                 page = read_page(file, index, bitmap, count);
 926                                 offset = 0;
 927                         } else {
 928                                 page = read_sb_page(bitmap->mddev, bitmap->offset, index);
 929                                 offset = 0;
 930                         }
 931                         if (IS_ERR(page)) { /* read error */
 932                                 ret = PTR_ERR(page);
 933                                 goto err;
 934                         }
 935
 936                         oldindex = index;
 937                         oldpage = page;
 938
 939                         if (outofdate) {
 940                                 /*
 941                                  * if bitmap is out of date, dirty the
 942                                  * whole page and write it out
 943                                  */
 944                                 paddr = kmap_atomic(page, KM_USER0);
 945                                 memset(paddr + offset, 0xff,
 946                                        PAGE_SIZE - offset);
 947                                 kunmap_atomic(paddr, KM_USER0);
 948                                 write_page(bitmap, page, 1);
 949
 950                                 ret = -EIO;
 951                                 if (bitmap->flags & BITMAP_WRITE_ERROR) {
 952                                         /* release, page not in filemap yet */
 953                                         put_page(page);
 954                                         goto err;
 955                                 }
 956                         }
 957
 958                         bitmap->filemap[bitmap->file_pages++] = page;
 959                         bitmap->last_page_size = count;
 960                 }
 961                 paddr = kmap_atomic(page, KM_USER0);
 962                 if (bitmap->flags & BITMAP_HOSTENDIAN)
 963                         b = test_bit(bit, paddr);
 964                 else
 965                         b = ext2_test_bit(bit, paddr);
 966                 kunmap_atomic(paddr, KM_USER0);
 967                 if (b) {
 968                         /* if the disk bit is set, set the memory bit */
 969                         bitmap_set_memory_bits(bitmap, i << CHUNK_BLOCK_SHIFT(bitmap),
 970                                                ((i+1) << (CHUNK_BLOCK_SHIFT(bitmap)) >= start)
 971                                 );
 972                         bit_cnt++;
 973                         set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
 974                 }
 975         }
 976
 977         /* everything went OK */
 978         ret = 0;
 979         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_UNSET);
 980
 981         if (bit_cnt) { /* Kick recovery if any bits were set */
 982                 set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
 983                 md_wakeup_thread(bitmap->mddev->thread);
 984         }
 985
 986         printk(KERN_INFO "%s: bitmap initialized from disk: "
 987                 "read %lu/%lu pages, set %lu bits\n",
 988                 bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt);
 989
 990         return 0;
 991
 992  err:
 993         printk(KERN_INFO "%s: bitmap initialisation failed: %d\n",
 994                bmname(bitmap), ret);
 995         return ret;
 996 }
 997
 998 void bitmap_write_all(struct bitmap *bitmap)
 999 {
1000         /* We don't actually write all bitmap blocks here,
1001          * just flag them as needing to be written
1002          */
1003         int i;
1004
1005         for (i=0; i < bitmap->file_pages; i++)
1006                 set_page_attr(bitmap, bitmap->filemap[i],
1007                               BITMAP_PAGE_NEEDWRITE);
1008 }
1009
1010
1011 static void bitmap_count_page(struct bitmap *bitmap, sector_t offset, int inc)
1012 {
1013         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1014         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1015         bitmap->bp[page].count += inc;
1016 /*
1017         if (page == 0) printk("count page 0, offset %llu: %d gives %d\n",
1018                               (unsigned long long)offset, inc, bitmap->bp[page].count);
1019 */
1020         bitmap_checkfree(bitmap, page);
1021 }
1022 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1023                                             sector_t offset, int *blocks,
1024                                             int create);
1025
1026 /*
1027  * bitmap daemon -- periodically wakes up to clean bits and flush pages
1028  *                      out to disk
1029  */
1030
1031 void bitmap_daemon_work(struct bitmap *bitmap)
1032 {
1033         unsigned long j;
1034         unsigned long flags;
1035         struct page *page = NULL, *lastpage = NULL;
1036         int blocks;
1037         void *paddr;
1038
1039         if (bitmap == NULL)
1040                 return;
1041         if (time_before(jiffies, bitmap->daemon_lastrun + bitmap->daemon_sleep*HZ))
1042                 goto done;
1043
1044         bitmap->daemon_lastrun = jiffies;
1045         if (bitmap->allclean) {
1046                 bitmap->mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1047                 return;
1048         }
1049         bitmap->allclean = 1;
1050
1051         for (j = 0; j < bitmap->chunks; j++) {
1052                 bitmap_counter_t *bmc;
1053                 spin_lock_irqsave(&bitmap->lock, flags);
1054                 if (!bitmap->filemap) {
1055                         /* error or shutdown */
1056                         spin_unlock_irqrestore(&bitmap->lock, flags);
1057                         break;
1058                 }
1059
1060                 page = filemap_get_page(bitmap, j);
1061
1062                 if (page != lastpage) {
1063                         /* skip this page unless it's marked as needing cleaning */
1064                         if (!test_page_attr(bitmap, page, BITMAP_PAGE_CLEAN)) {
1065                                 int need_write = test_page_attr(bitmap, page,
1066                                                                 BITMAP_PAGE_NEEDWRITE);
1067                                 if (need_write)
1068                                         clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
1069
1070                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1071                                 if (need_write) {
1072                                         write_page(bitmap, page, 0);
1073                                         bitmap->allclean = 0;
1074                                 }
1075                                 continue;
1076                         }
1077
1078                         /* grab the new page, sync and release the old */
1079                         if (lastpage != NULL) {
1080                                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1081                                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1082                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1083                                         write_page(bitmap, lastpage, 0);
1084                                 } else {
1085                                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1086                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1087                                 }
1088                         } else
1089                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1090                         lastpage = page;
1091
1092                         /* We are possibly going to clear some bits, so make
1093                          * sure that events_cleared is up-to-date.
1094                          */
1095                         if (bitmap->need_sync) {
1096                                 bitmap_super_t *sb;
1097                                 bitmap->need_sync = 0;
1098                                 sb = kmap_atomic(bitmap->sb_page, KM_USER0);
1099                                 sb->events_cleared =
1100                                         cpu_to_le64(bitmap->events_cleared);
1101                                 kunmap_atomic(sb, KM_USER0);
1102                                 write_page(bitmap, bitmap->sb_page, 1);
1103                         }
1104                         spin_lock_irqsave(&bitmap->lock, flags);
1105                         clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1106                 }
1107                 bmc = bitmap_get_counter(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
1108                                         &blocks, 0);
1109                 if (bmc) {
1110 /*
1111   if (j < 100) printk("bitmap: j=%lu, *bmc = 0x%x\n", j, *bmc);
1112 */
1113                         if (*bmc)
1114                                 bitmap->allclean = 0;
1115
1116                         if (*bmc == 2) {
1117                                 *bmc=1; /* maybe clear the bit next time */
1118                                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1119                         } else if (*bmc == 1) {
1120                                 /* we can clear the bit */
1121                                 *bmc = 0;
1122                                 bitmap_count_page(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
1123                                                   -1);
1124
1125                                 /* clear the bit */
1126                                 paddr = kmap_atomic(page, KM_USER0);
1127                                 if (bitmap->flags & BITMAP_HOSTENDIAN)
1128                                         clear_bit(file_page_offset(j), paddr);
1129                                 else
1130                                         ext2_clear_bit(file_page_offset(j), paddr);
1131                                 kunmap_atomic(paddr, KM_USER0);
1132                         }
1133                 }
1134                 spin_unlock_irqrestore(&bitmap->lock, flags);
1135         }
1136
1137         /* now sync the final page */
1138         if (lastpage != NULL) {
1139                 spin_lock_irqsave(&bitmap->lock, flags);
1140                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1141                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1142                         spin_unlock_irqrestore(&bitmap->lock, flags);
1143                         write_page(bitmap, lastpage, 0);
1144                 } else {
1145                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1146                         spin_unlock_irqrestore(&bitmap->lock, flags);
1147                 }
1148         }
1149
1150  done:
1151         if (bitmap->allclean == 0)
1152                 bitmap->mddev->thread->timeout = bitmap->daemon_sleep * HZ;
1153 }
1154
1155 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1156                                             sector_t offset, int *blocks,
1157                                             int create)
1158 {
1159         /* If 'create', we might release the lock and reclaim it.
1160          * The lock must have been taken with interrupts enabled.
1161          * If !create, we don't release the lock.
1162          */
1163         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1164         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1165         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1166         sector_t csize;
1167
1168         if (bitmap_checkpage(bitmap, page, create) < 0) {
1169                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1170                 *blocks = csize - (offset & (csize- 1));
1171                 return NULL;
1172         }
1173         /* now locked ... */
1174
1175         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1176                 /* should we use the first or second counter field
1177                  * of the hijacked pointer? */
1178                 int hi = (pageoff > PAGE_COUNTER_MASK);
1179                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap) +
1180                                           PAGE_COUNTER_SHIFT - 1);
1181                 *blocks = csize - (offset & (csize- 1));
1182                 return  &((bitmap_counter_t *)
1183                           &bitmap->bp[page].map)[hi];
1184         } else { /* page is allocated */
1185                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1186                 *blocks = csize - (offset & (csize- 1));
1187                 return (bitmap_counter_t *)
1188                         &(bitmap->bp[page].map[pageoff]);
1189         }
1190 }
1191
1192 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1193 {
1194         if (!bitmap) return 0;
1195
1196         if (behind) {
1197                 atomic_inc(&bitmap->behind_writes);
1198                 PRINTK(KERN_DEBUG "inc write-behind count %d/%d\n",
1199                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1200         }
1201
1202         while (sectors) {
1203                 int blocks;
1204                 bitmap_counter_t *bmc;
1205
1206                 spin_lock_irq(&bitmap->lock);
1207                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 1);
1208                 if (!bmc) {
1209                         spin_unlock_irq(&bitmap->lock);
1210                         return 0;
1211                 }
1212
1213                 if (unlikely((*bmc & COUNTER_MAX) == COUNTER_MAX)) {
1214                         DEFINE_WAIT(__wait);
1215                         /* note that it is safe to do the prepare_to_wait
1216                          * after the test as long as we do it before dropping
1217                          * the spinlock.
1218                          */
1219                         prepare_to_wait(&bitmap->overflow_wait, &__wait,
1220                                         TASK_UNINTERRUPTIBLE);
1221                         spin_unlock_irq(&bitmap->lock);
1222                         blk_unplug(bitmap->mddev->queue);
1223                         schedule();
1224                         finish_wait(&bitmap->overflow_wait, &__wait);
1225                         continue;
1226                 }
1227
1228                 switch(*bmc) {
1229                 case 0:
1230                         bitmap_file_set_bit(bitmap, offset);
1231                         bitmap_count_page(bitmap,offset, 1);
1232                         blk_plug_device(bitmap->mddev->queue);
1233                         /* fall through */
1234                 case 1:
1235                         *bmc = 2;
1236                 }
1237
1238                 (*bmc)++;
1239
1240                 spin_unlock_irq(&bitmap->lock);
1241
1242                 offset += blocks;
1243                 if (sectors > blocks)
1244                         sectors -= blocks;
1245                 else sectors = 0;
1246         }
1247         bitmap->allclean = 0;
1248         return 0;
1249 }
1250
1251 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1252                      int success, int behind)
1253 {
1254         if (!bitmap) return;
1255         if (behind) {
1256                 atomic_dec(&bitmap->behind_writes);
1257                 PRINTK(KERN_DEBUG "dec write-behind count %d/%d\n",
1258                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1259         }
1260
1261         while (sectors) {
1262                 int blocks;
1263                 unsigned long flags;
1264                 bitmap_counter_t *bmc;
1265
1266                 spin_lock_irqsave(&bitmap->lock, flags);
1267                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 0);
1268                 if (!bmc) {
1269                         spin_unlock_irqrestore(&bitmap->lock, flags);
1270                         return;
1271                 }
1272
1273                 if (success &&
1274                     bitmap->events_cleared < bitmap->mddev->events) {
1275                         bitmap->events_cleared = bitmap->mddev->events;
1276                         bitmap->need_sync = 1;
1277                 }
1278
1279                 if (!success && ! (*bmc & NEEDED_MASK))
1280                         *bmc |= NEEDED_MASK;
1281
1282                 if ((*bmc & COUNTER_MAX) == COUNTER_MAX)
1283                         wake_up(&bitmap->overflow_wait);
1284
1285                 (*bmc)--;
1286                 if (*bmc <= 2) {
1287                         set_page_attr(bitmap,
1288                                       filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1289                                       BITMAP_PAGE_CLEAN);
1290                 }
1291                 spin_unlock_irqrestore(&bitmap->lock, flags);
1292                 offset += blocks;
1293                 if (sectors > blocks)
1294                         sectors -= blocks;
1295                 else sectors = 0;
1296         }
1297 }
1298
1299 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
1300                         int degraded)
1301 {
1302         bitmap_counter_t *bmc;
1303         int rv;
1304         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1305                 *blocks = 1024;
1306                 return 1; /* always resync if no bitmap */
1307         }
1308         spin_lock_irq(&bitmap->lock);
1309         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1310         rv = 0;
1311         if (bmc) {
1312                 /* locked */
1313                 if (RESYNC(*bmc))
1314                         rv = 1;
1315                 else if (NEEDED(*bmc)) {
1316                         rv = 1;
1317                         if (!degraded) { /* don't set/clear bits if degraded */
1318                                 *bmc |= RESYNC_MASK;
1319                                 *bmc &= ~NEEDED_MASK;
1320                         }
1321                 }
1322         }
1323         spin_unlock_irq(&bitmap->lock);
1324         bitmap->allclean = 0;
1325         return rv;
1326 }
1327
1328 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int aborted)
1329 {
1330         bitmap_counter_t *bmc;
1331         unsigned long flags;
1332 /*
1333         if (offset == 0) printk("bitmap_end_sync 0 (%d)\n", aborted);
1334 */      if (bitmap == NULL) {
1335                 *blocks = 1024;
1336                 return;
1337         }
1338         spin_lock_irqsave(&bitmap->lock, flags);
1339         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1340         if (bmc == NULL)
1341                 goto unlock;
1342         /* locked */
1343 /*
1344         if (offset == 0) printk("bitmap_end sync found 0x%x, blocks %d\n", *bmc, *blocks);
1345 */
1346         if (RESYNC(*bmc)) {
1347                 *bmc &= ~RESYNC_MASK;
1348
1349                 if (!NEEDED(*bmc) && aborted)
1350                         *bmc |= NEEDED_MASK;
1351                 else {
1352                         if (*bmc <= 2) {
1353                                 set_page_attr(bitmap,
1354                                               filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1355                                               BITMAP_PAGE_CLEAN);
1356                         }
1357                 }
1358         }
1359  unlock:
1360         spin_unlock_irqrestore(&bitmap->lock, flags);
1361         bitmap->allclean = 0;
1362 }
1363
1364 void bitmap_close_sync(struct bitmap *bitmap)
1365 {
1366         /* Sync has finished, and any bitmap chunks that weren't synced
1367          * properly have been aborted.  It remains to us to clear the
1368          * RESYNC bit wherever it is still on
1369          */
1370         sector_t sector = 0;
1371         int blocks;
1372         if (!bitmap)
1373                 return;
1374         while (sector < bitmap->mddev->resync_max_sectors) {
1375                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1376                 sector += blocks;
1377         }
1378 }
1379
1380 void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector)
1381 {
1382         sector_t s = 0;
1383         int blocks;
1384
1385         if (!bitmap)
1386                 return;
1387         if (sector == 0) {
1388                 bitmap->last_end_sync = jiffies;
1389                 return;
1390         }
1391         if (time_before(jiffies, (bitmap->last_end_sync
1392                                   + bitmap->daemon_sleep * HZ)))
1393                 return;
1394         wait_event(bitmap->mddev->recovery_wait,
1395                    atomic_read(&bitmap->mddev->recovery_active) == 0);
1396
1397         sector &= ~((1ULL << CHUNK_BLOCK_SHIFT(bitmap)) - 1);
1398         s = 0;
1399         while (s < sector && s < bitmap->mddev->resync_max_sectors) {
1400                 bitmap_end_sync(bitmap, s, &blocks, 0);
1401                 s += blocks;
1402         }
1403         bitmap->last_end_sync = jiffies;
1404 }
1405
1406 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1407 {
1408         /* For each chunk covered by any of these sectors, set the
1409          * counter to 1 and set resync_needed.  They should all
1410          * be 0 at this point
1411          */
1412
1413         int secs;
1414         bitmap_counter_t *bmc;
1415         spin_lock_irq(&bitmap->lock);
1416         bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
1417         if (!bmc) {
1418                 spin_unlock_irq(&bitmap->lock);
1419                 return;
1420         }
1421         if (! *bmc) {
1422                 struct page *page;
1423                 *bmc = 1 | (needed?NEEDED_MASK:0);
1424                 bitmap_count_page(bitmap, offset, 1);
1425                 page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));
1426                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1427         }
1428         spin_unlock_irq(&bitmap->lock);
1429         bitmap->allclean = 0;
1430 }
1431
1432 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
1433 void bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1434 {
1435         unsigned long chunk;
1436
1437         for (chunk = s; chunk <= e; chunk++) {
1438                 sector_t sec = chunk << CHUNK_BLOCK_SHIFT(bitmap);
1439                 bitmap_set_memory_bits(bitmap, sec, 1);
1440                 bitmap_file_set_bit(bitmap, sec);
1441         }
1442 }
1443
1444 /*
1445  * flush out any pending updates
1446  */
1447 void bitmap_flush(mddev_t *mddev)
1448 {
1449         struct bitmap *bitmap = mddev->bitmap;
1450         int sleep;
1451
1452         if (!bitmap) /* there was no bitmap */
1453                 return;
1454
1455         /* run the daemon_work three time to ensure everything is flushed
1456          * that can be
1457          */
1458         sleep = bitmap->daemon_sleep;
1459         bitmap->daemon_sleep = 0;
1460         bitmap_daemon_work(bitmap);
1461         bitmap_daemon_work(bitmap);
1462         bitmap_daemon_work(bitmap);
1463         bitmap->daemon_sleep = sleep;
1464         bitmap_update_sb(bitmap);
1465 }
1466
1467 /*
1468  * free memory that was allocated
1469  */
1470 static void bitmap_free(struct bitmap *bitmap)
1471 {
1472         unsigned long k, pages;
1473         struct bitmap_page *bp;
1474
1475         if (!bitmap) /* there was no bitmap */
1476                 return;
1477
1478         /* release the bitmap file and kill the daemon */
1479         bitmap_file_put(bitmap);
1480
1481         bp = bitmap->bp;
1482         pages = bitmap->pages;
1483
1484         /* free all allocated memory */
1485
1486         if (bp) /* deallocate the page memory */
1487                 for (k = 0; k < pages; k++)
1488                         if (bp[k].map && !bp[k].hijacked)
1489                                 kfree(bp[k].map);
1490         kfree(bp);
1491         kfree(bitmap);
1492 }
1493 void bitmap_destroy(mddev_t *mddev)
1494 {
1495         struct bitmap *bitmap = mddev->bitmap;
1496
1497         if (!bitmap) /* there was no bitmap */
1498                 return;
1499
1500         mddev->bitmap = NULL; /* disconnect from the md device */
1501         if (mddev->thread)
1502                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1503
1504         bitmap_free(bitmap);
1505 }
1506
1507 /*
1508  * initialize the bitmap structure
1509  * if this returns an error, bitmap_destroy must be called to do clean up
1510  */
1511 int bitmap_create(mddev_t *mddev)
1512 {
1513         struct bitmap *bitmap;
1514         unsigned long blocks = mddev->resync_max_sectors;
1515         unsigned long chunks;
1516         unsigned long pages;
1517         struct file *file = mddev->bitmap_file;
1518         int err;
1519         sector_t start;
1520
1521         BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
1522
1523         if (!file && !mddev->bitmap_offset) /* bitmap disabled, nothing to do */
1524                 return 0;
1525
1526         BUG_ON(file && mddev->bitmap_offset);
1527
1528         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1529         if (!bitmap)
1530                 return -ENOMEM;
1531
1532         spin_lock_init(&bitmap->lock);
1533         atomic_set(&bitmap->pending_writes, 0);
1534         init_waitqueue_head(&bitmap->write_wait);
1535         init_waitqueue_head(&bitmap->overflow_wait);
1536
1537         bitmap->mddev = mddev;
1538
1539         bitmap->file = file;
1540         bitmap->offset = mddev->bitmap_offset;
1541         if (file) {
1542                 get_file(file);
1543                 do_sync_mapping_range(file->f_mapping, 0, LLONG_MAX,
1544                                       SYNC_FILE_RANGE_WAIT_BEFORE |
1545                                       SYNC_FILE_RANGE_WRITE |
1546                                       SYNC_FILE_RANGE_WAIT_AFTER);
1547         }
1548         /* read superblock from bitmap file (this sets bitmap->chunksize) */
1549         err = bitmap_read_sb(bitmap);
1550         if (err)
1551                 goto error;
1552
1553         bitmap->chunkshift = ffz(~bitmap->chunksize);
1554
1555         /* now that chunksize and chunkshift are set, we can use these macros */
1556         chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) /
1557                         CHUNK_BLOCK_RATIO(bitmap);
1558         pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
1559
1560         BUG_ON(!pages);
1561
1562         bitmap->chunks = chunks;
1563         bitmap->pages = pages;
1564         bitmap->missing_pages = pages;
1565         bitmap->counter_bits = COUNTER_BITS;
1566
1567         bitmap->syncchunk = ~0UL;
1568
1569 #ifdef INJECT_FATAL_FAULT_1
1570         bitmap->bp = NULL;
1571 #else
1572         bitmap->bp = kzalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
1573 #endif
1574         err = -ENOMEM;
1575         if (!bitmap->bp)
1576                 goto error;
1577
1578         /* now that we have some pages available, initialize the in-memory
1579          * bitmap from the on-disk bitmap */
1580         start = 0;
1581         if (mddev->degraded == 0
1582             || bitmap->events_cleared == mddev->events)
1583                 /* no need to keep dirty bits to optimise a re-add of a missing device */
1584                 start = mddev->recovery_cp;
1585         err = bitmap_init_from_disk(bitmap, start);
1586
1587         if (err)
1588                 goto error;
1589
1590         printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
1591                 pages, bmname(bitmap));
1592
1593         mddev->bitmap = bitmap;
1594
1595         mddev->thread->timeout = bitmap->daemon_sleep * HZ;
1596
1597         bitmap_update_sb(bitmap);
1598
1599         return (bitmap->flags & BITMAP_WRITE_ERROR) ? -EIO : 0;
1600
1601  error:
1602         bitmap_free(bitmap);
1603         return err;
1604 }
1605
1606 /* the bitmap API -- for raid personalities */
1607 EXPORT_SYMBOL(bitmap_startwrite);
1608 EXPORT_SYMBOL(bitmap_endwrite);
1609 EXPORT_SYMBOL(bitmap_start_sync);
1610 EXPORT_SYMBOL(bitmap_end_sync);
1611 EXPORT_SYMBOL(bitmap_unplug);
1612 EXPORT_SYMBOL(bitmap_close_sync);
1613 EXPORT_SYMBOL(bitmap_cond_end_sync);