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