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