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