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