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/config.h>
  24 #include <linux/timer.h>
  25 #include <linux/sched.h>
  26 #include <linux/list.h>
  27 #include <linux/file.h>
  28 #include <linux/mount.h>
  29 #include <linux/buffer_head.h>
  30 #include <linux/raid/md.h>
  31 #include <linux/raid/bitmap.h>
  32
  33 /* debug macros */
  34
  35 #define DEBUG 0
  36
  37 #if DEBUG
  38 /* these are for debugging purposes only! */
  39
  40 /* define one and only one of these */
  41 #define INJECT_FAULTS_1 0 /* cause bitmap_alloc_page to fail always */
  42 #define INJECT_FAULTS_2 0 /* cause bitmap file to be kicked when first bit set*/
  43 #define INJECT_FAULTS_3 0 /* treat bitmap file as kicked at init time */
  44 #define INJECT_FAULTS_4 0 /* undef */
  45 #define INJECT_FAULTS_5 0 /* undef */
  46 #define INJECT_FAULTS_6 0
  47
  48 /* if these are defined, the driver will fail! debug only */
  49 #define INJECT_FATAL_FAULT_1 0 /* fail kmalloc, causing bitmap_create to fail */
  50 #define INJECT_FATAL_FAULT_2 0 /* undef */
  51 #define INJECT_FATAL_FAULT_3 0 /* undef */
  52 #endif
  53
  54 //#define DPRINTK PRINTK /* set this NULL to avoid verbose debug output */
  55 #define DPRINTK(x...) do { } while(0)
  56
  57 #ifndef PRINTK
  58 #  if DEBUG > 0
  59 #    define PRINTK(x...) printk(KERN_DEBUG x)
  60 #  else
  61 #    define PRINTK(x...)
  62 #  endif
  63 #endif
  64
  65 static inline char * bmname(struct bitmap *bitmap)
  66 {
  67         return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
  68 }
  69
  70
  71 /*
  72  * just a placeholder - calls kmalloc for bitmap pages
  73  */
  74 static unsigned char *bitmap_alloc_page(struct bitmap *bitmap)
  75 {
  76         unsigned char *page;
  77
  78 #ifdef INJECT_FAULTS_1
  79         page = NULL;
  80 #else
  81         page = kmalloc(PAGE_SIZE, GFP_NOIO);
  82 #endif
  83         if (!page)
  84                 printk("%s: bitmap_alloc_page FAILED\n", bmname(bitmap));
  85         else
  86                 PRINTK("%s: bitmap_alloc_page: allocated page at %p\n",
  87                         bmname(bitmap), page);
  88         return page;
  89 }
  90
  91 /*
  92  * for now just a placeholder -- just calls kfree for bitmap pages
  93  */
  94 static void bitmap_free_page(struct bitmap *bitmap, unsigned char *page)
  95 {
  96         PRINTK("%s: bitmap_free_page: free page %p\n", bmname(bitmap), page);
  97         kfree(page);
  98 }
  99
 100 /*
 101  * check a page and, if necessary, allocate it (or hijack it if the alloc fails)
 102  *
 103  * 1) check to see if this page is allocated, if it's not then try to alloc
 104  * 2) if the alloc fails, set the page's hijacked flag so we'll use the
 105  *    page pointer directly as a counter
 106  *
 107  * if we find our page, we increment the page's refcount so that it stays
 108  * allocated while we're using it
 109  */
 110 static int bitmap_checkpage(struct bitmap *bitmap, unsigned long page, int create)
 111 {
 112         unsigned char *mappage;
 113
 114         if (page >= bitmap->pages) {
 115                 printk(KERN_ALERT
 116                         "%s: invalid bitmap page request: %lu (> %lu)\n",
 117                         bmname(bitmap), page, bitmap->pages-1);
 118                 return -EINVAL;
 119         }
 120
 121
 122         if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
 123                 return 0;
 124
 125         if (bitmap->bp[page].map) /* page is already allocated, just return */
 126                 return 0;
 127
 128         if (!create)
 129                 return -ENOENT;
 130
 131         spin_unlock_irq(&bitmap->lock);
 132
 133         /* this page has not been allocated yet */
 134
 135         if ((mappage = bitmap_alloc_page(bitmap)) == NULL) {
 136                 PRINTK("%s: bitmap map page allocation failed, hijacking\n",
 137                         bmname(bitmap));
 138                 /* failed - set the hijacked flag so that we can use the
 139                  * pointer as a counter */
 140                 spin_lock_irq(&bitmap->lock);
 141                 if (!bitmap->bp[page].map)
 142                         bitmap->bp[page].hijacked = 1;
 143                 goto out;
 144         }
 145
 146         /* got a page */
 147
 148         spin_lock_irq(&bitmap->lock);
 149
 150         /* recheck the page */
 151
 152         if (bitmap->bp[page].map || bitmap->bp[page].hijacked) {
 153                 /* somebody beat us to getting the page */
 154                 bitmap_free_page(bitmap, mappage);
 155                 return 0;
 156         }
 157
 158         /* no page was in place and we have one, so install it */
 159
 160         memset(mappage, 0, PAGE_SIZE);
 161         bitmap->bp[page].map = mappage;
 162         bitmap->missing_pages--;
 163 out:
 164         return 0;
 165 }
 166
 167
 168 /* if page is completely empty, put it back on the free list, or dealloc it */
 169 /* if page was hijacked, unmark the flag so it might get alloced next time */
 170 /* Note: lock should be held when calling this */
 171 static void bitmap_checkfree(struct bitmap *bitmap, unsigned long page)
 172 {
 173         char *ptr;
 174
 175         if (bitmap->bp[page].count) /* page is still busy */
 176                 return;
 177
 178         /* page is no longer in use, it can be released */
 179
 180         if (bitmap->bp[page].hijacked) { /* page was hijacked, undo this now */
 181                 bitmap->bp[page].hijacked = 0;
 182                 bitmap->bp[page].map = NULL;
 183                 return;
 184         }
 185
 186         /* normal case, free the page */
 187
 188 #if 0
 189 /* actually ... let's not.  We will probably need the page again exactly when
 190  * memory is tight and we are flusing to disk
 191  */
 192         return;
 193 #else
 194         ptr = bitmap->bp[page].map;
 195         bitmap->bp[page].map = NULL;
 196         bitmap->missing_pages++;
 197         bitmap_free_page(bitmap, ptr);
 198         return;
 199 #endif
 200 }
 201
 202
 203 /*
 204  * bitmap file handling - read and write the bitmap file and its superblock
 205  */
 206
 207 /* copy the pathname of a file to a buffer */
 208 char *file_path(struct file *file, char *buf, int count)
 209 {
 210         struct dentry *d;
 211         struct vfsmount *v;
 212
 213         if (!buf)
 214                 return NULL;
 215
 216         d = file->f_dentry;
 217         v = file->f_vfsmnt;
 218
 219         buf = d_path(d, v, buf, count);
 220
 221         return IS_ERR(buf) ? NULL : buf;
 222 }
 223
 224 /*
 225  * basic page I/O operations
 226  */
 227
 228 /* IO operations when bitmap is stored near all superblocks */
 229 static struct page *read_sb_page(mddev_t *mddev, long offset, unsigned long index)
 230 {
 231         /* choose a good rdev and read the page from there */
 232
 233         mdk_rdev_t *rdev;
 234         struct list_head *tmp;
 235         struct page *page = alloc_page(GFP_KERNEL);
 236         sector_t target;
 237
 238         if (!page)
 239                 return ERR_PTR(-ENOMEM);
 240
 241         ITERATE_RDEV(mddev, rdev, tmp) {
 242                 if (! test_bit(In_sync, &rdev->flags)
 243                     || test_bit(Faulty, &rdev->flags))
 244                         continue;
 245
 246                 target = (rdev->sb_offset << 1) + offset + index * (PAGE_SIZE/512);
 247
 248                 if (sync_page_io(rdev->bdev, target, PAGE_SIZE, page, READ)) {
 249                         page->index = index;
 250                         attach_page_buffers(page, NULL); /* so that free_buffer will
 251                                                           * quietly no-op */
 252                         return page;
 253                 }
 254         }
 255         return ERR_PTR(-EIO);
 256
 257 }
 258
 259 static int write_sb_page(mddev_t *mddev, long offset, struct page *page, int wait)
 260 {
 261         mdk_rdev_t *rdev;
 262         struct list_head *tmp;
 263
 264         ITERATE_RDEV(mddev, rdev, tmp)
 265                 if (test_bit(In_sync, &rdev->flags)
 266                     && !test_bit(Faulty, &rdev->flags))
 267                         md_super_write(mddev, rdev,
 268                                        (rdev->sb_offset<<1) + offset
 269                                        + page->index * (PAGE_SIZE/512),
 270                                        PAGE_SIZE,
 271                                        page);
 272
 273         if (wait)
 274                 md_super_wait(mddev);
 275         return 0;
 276 }
 277
 278 /*
 279  * write out a page to a file
 280  */
 281 static int write_page(struct bitmap *bitmap, struct page *page, int wait)
 282 {
 283         struct buffer_head *bh;
 284
 285         if (bitmap->file == NULL)
 286                 return write_sb_page(bitmap->mddev, bitmap->offset, page, wait);
 287
 288         bh = page_buffers(page);
 289
 290         while (bh && bh->b_blocknr) {
 291                 atomic_inc(&bitmap->pending_writes);
 292                 set_buffer_locked(bh);
 293                 set_buffer_mapped(bh);
 294                 submit_bh(WRITE, bh);
 295                 bh = bh->b_this_page;
 296         }
 297
 298         if (wait) {
 299                 wait_event(bitmap->write_wait,
 300                            atomic_read(&bitmap->pending_writes)==0);
 301                 return (bitmap->flags & BITMAP_WRITE_ERROR) ? -EIO : 0;
 302         }
 303         return 0;
 304 }
 305
 306 static void end_bitmap_write(struct buffer_head *bh, int uptodate)
 307 {
 308         struct bitmap *bitmap = bh->b_private;
 309         unsigned long flags;
 310
 311         if (!uptodate) {
 312                 spin_lock_irqsave(&bitmap->lock, flags);
 313                 bitmap->flags |= BITMAP_WRITE_ERROR;
 314                 spin_unlock_irqrestore(&bitmap->lock, flags);
 315         }
 316         if (atomic_dec_and_test(&bitmap->pending_writes))
 317                 wake_up(&bitmap->write_wait);
 318 }
 319
 320 /* copied from buffer.c */
 321 static void
 322 __clear_page_buffers(struct page *page)
 323 {
 324         ClearPagePrivate(page);
 325         set_page_private(page, 0);
 326         page_cache_release(page);
 327 }
 328 static void free_buffers(struct page *page)
 329 {
 330         struct buffer_head *bh = page_buffers(page);
 331
 332         while (bh) {
 333                 struct buffer_head *next = bh->b_this_page;
 334                 free_buffer_head(bh);
 335                 bh = next;
 336         }
 337         __clear_page_buffers(page);
 338         put_page(page);
 339 }
 340
 341 /* read a page from a file.
 342  * We both read the page, and attach buffers to the page to record the
 343  * address of each block (using bmap).  These addresses will be used
 344  * to write the block later, completely bypassing the filesystem.
 345  * This usage is similar to how swap files are handled, and allows us
 346  * to write to a file with no concerns of memory allocation failing.
 347  */
 348 static struct page *read_page(struct file *file, unsigned long index,
 349                               struct bitmap *bitmap,
 350                               unsigned long count)
 351 {
 352         struct page *page = NULL;
 353         struct inode *inode = file->f_dentry->d_inode;
 354         struct buffer_head *bh;
 355         sector_t block;
 356
 357         PRINTK("read bitmap file (%dB @ %Lu)\n", (int)PAGE_SIZE,
 358                         (unsigned long long)index << PAGE_SHIFT);
 359
 360         page = alloc_page(GFP_KERNEL);
 361         if (!page)
 362                 page = ERR_PTR(-ENOMEM);
 363         if (IS_ERR(page))
 364                 goto out;
 365
 366         bh = alloc_page_buffers(page, 1<<inode->i_blkbits, 0);
 367         if (!bh) {
 368                 put_page(page);
 369                 page = ERR_PTR(-ENOMEM);
 370                 goto out;
 371         }
 372         attach_page_buffers(page, bh);
 373         block = index << (PAGE_SHIFT - inode->i_blkbits);
 374         while (bh) {
 375                 if (count == 0)
 376                         bh->b_blocknr = 0;
 377                 else {
 378                         bh->b_blocknr = bmap(inode, block);
 379                         if (bh->b_blocknr == 0) {
 380                                 /* Cannot use this file! */
 381                                 free_buffers(page);
 382                                 page = ERR_PTR(-EINVAL);
 383                                 goto out;
 384                         }
 385                         bh->b_bdev = inode->i_sb->s_bdev;
 386                         if (count < (1<<inode->i_blkbits))
 387                                 count = 0;
 388                         else
 389                                 count -= (1<<inode->i_blkbits);
 390
 391                         bh->b_end_io = end_bitmap_write;
 392                         bh->b_private = bitmap;
 393                         atomic_inc(&bitmap->pending_writes);
 394                         set_buffer_locked(bh);
 395                         set_buffer_mapped(bh);
 396                         submit_bh(READ, bh);
 397                 }
 398                 block++;
 399                 bh = bh->b_this_page;
 400         }
 401         page->index = index;
 402
 403         wait_event(bitmap->write_wait,
 404                    atomic_read(&bitmap->pending_writes)==0);
 405         if (bitmap->flags & BITMAP_WRITE_ERROR) {
 406                 free_buffers(page);
 407                 page = ERR_PTR(-EIO);
 408         }
 409 out:
 410         if (IS_ERR(page))
 411                 printk(KERN_ALERT "md: bitmap read error: (%dB @ %Lu): %ld\n",
 412                         (int)PAGE_SIZE,
 413                         (unsigned long long)index << PAGE_SHIFT,
 414                         PTR_ERR(page));
 415         return page;
 416 }
 417
 418 /*
 419  * bitmap file superblock operations
 420  */
 421
 422 /* update the event counter and sync the superblock to disk */
 423 int bitmap_update_sb(struct bitmap *bitmap)
 424 {
 425         bitmap_super_t *sb;
 426         unsigned long flags;
 427
 428         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
 429                 return 0;
 430         spin_lock_irqsave(&bitmap->lock, flags);
 431         if (!bitmap->sb_page) { /* no superblock */
 432                 spin_unlock_irqrestore(&bitmap->lock, flags);
 433                 return 0;
 434         }
 435         spin_unlock_irqrestore(&bitmap->lock, flags);
 436         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
 437         sb->events = cpu_to_le64(bitmap->mddev->events);
 438         if (!bitmap->mddev->degraded)
 439                 sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
 440         kunmap_atomic(sb, KM_USER0);
 441         return write_page(bitmap, bitmap->sb_page, 1);
 442 }
 443
 444 /* print out the bitmap file superblock */
 445 void bitmap_print_sb(struct bitmap *bitmap)
 446 {
 447         bitmap_super_t *sb;
 448
 449         if (!bitmap || !bitmap->sb_page)
 450                 return;
 451         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
 452         printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
 453         printk(KERN_DEBUG "         magic: %08x\n", le32_to_cpu(sb->magic));
 454         printk(KERN_DEBUG "       version: %d\n", le32_to_cpu(sb->version));
 455         printk(KERN_DEBUG "          uuid: %08x.%08x.%08x.%08x\n",
 456                                         *(__u32 *)(sb->uuid+0),
 457                                         *(__u32 *)(sb->uuid+4),
 458                                         *(__u32 *)(sb->uuid+8),
 459                                         *(__u32 *)(sb->uuid+12));
 460         printk(KERN_DEBUG "        events: %llu\n",
 461                         (unsigned long long) le64_to_cpu(sb->events));
 462         printk(KERN_DEBUG "events cleared: %llu\n",
 463                         (unsigned long long) le64_to_cpu(sb->events_cleared));
 464         printk(KERN_DEBUG "         state: %08x\n", le32_to_cpu(sb->state));
 465         printk(KERN_DEBUG "     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
 466         printk(KERN_DEBUG "  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
 467         printk(KERN_DEBUG "     sync size: %llu KB\n",
 468                         (unsigned long long)le64_to_cpu(sb->sync_size)/2);
 469         printk(KERN_DEBUG "max write behind: %d\n", le32_to_cpu(sb->write_behind));
 470         kunmap_atomic(sb, KM_USER0);
 471 }
 472
 473 /* read the superblock from the bitmap file and initialize some bitmap fields */
 474 static int bitmap_read_sb(struct bitmap *bitmap)
 475 {
 476         char *reason = NULL;
 477         bitmap_super_t *sb;
 478         unsigned long chunksize, daemon_sleep, write_behind;
 479         unsigned long long events;
 480         int err = -EINVAL;
 481
 482         /* page 0 is the superblock, read it... */
 483         if (bitmap->file)
 484                 bitmap->sb_page = read_page(bitmap->file, 0, bitmap, PAGE_SIZE);
 485         else {
 486                 bitmap->sb_page = read_sb_page(bitmap->mddev, bitmap->offset, 0);
 487         }
 488         if (IS_ERR(bitmap->sb_page)) {
 489                 err = PTR_ERR(bitmap->sb_page);
 490                 bitmap->sb_page = NULL;
 491                 return err;
 492         }
 493
 494         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
 495
 496         chunksize = le32_to_cpu(sb->chunksize);
 497         daemon_sleep = le32_to_cpu(sb->daemon_sleep);
 498         write_behind = le32_to_cpu(sb->write_behind);
 499
 500         /* verify that the bitmap-specific fields are valid */
 501         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
 502                 reason = "bad magic";
 503         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
 504                  le32_to_cpu(sb->version) > BITMAP_MAJOR_HI)
 505                 reason = "unrecognized superblock version";
 506         else if (chunksize < PAGE_SIZE)
 507                 reason = "bitmap chunksize too small";
 508         else if ((1 << ffz(~chunksize)) != chunksize)
 509                 reason = "bitmap chunksize not a power of 2";
 510         else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT / HZ)
 511                 reason = "daemon sleep period out of range";
 512         else if (write_behind > COUNTER_MAX)
 513                 reason = "write-behind limit out of range (0 - 16383)";
 514         if (reason) {
 515                 printk(KERN_INFO "%s: invalid bitmap file superblock: %s\n",
 516                         bmname(bitmap), reason);
 517                 goto out;
 518         }
 519
 520         /* keep the array size field of the bitmap superblock up to date */
 521         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 522
 523         if (!bitmap->mddev->persistent)
 524                 goto success;
 525
 526         /*
 527          * if we have a persistent array superblock, compare the
 528          * bitmap's UUID and event counter to the mddev's
 529          */
 530         if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
 531                 printk(KERN_INFO "%s: bitmap superblock UUID mismatch\n",
 532                         bmname(bitmap));
 533                 goto out;
 534         }
 535         events = le64_to_cpu(sb->events);
 536         if (events < bitmap->mddev->events) {
 537                 printk(KERN_INFO "%s: bitmap file is out of date (%llu < %llu) "
 538                         "-- forcing full recovery\n", bmname(bitmap), events,
 539                         (unsigned long long) bitmap->mddev->events);
 540                 sb->state |= BITMAP_STALE;
 541         }
 542 success:
 543         /* assign fields using values from superblock */
 544         bitmap->chunksize = chunksize;
 545         bitmap->daemon_sleep = daemon_sleep;
 546         bitmap->daemon_lastrun = jiffies;
 547         bitmap->max_write_behind = write_behind;
 548         bitmap->flags |= sb->state;
 549         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
 550                 bitmap->flags |= BITMAP_HOSTENDIAN;
 551         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
 552         if (sb->state & BITMAP_STALE)
 553                 bitmap->events_cleared = bitmap->mddev->events;
 554         err = 0;
 555 out:
 556         kunmap_atomic(sb, KM_USER0);
 557         if (err)
 558                 bitmap_print_sb(bitmap);
 559         return err;
 560 }
 561
 562 enum bitmap_mask_op {
 563         MASK_SET,
 564         MASK_UNSET
 565 };
 566
 567 /* record the state of the bitmap in the superblock */
 568 static void bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
 569                                 enum bitmap_mask_op op)
 570 {
 571         bitmap_super_t *sb;
 572         unsigned long flags;
 573
 574         spin_lock_irqsave(&bitmap->lock, flags);
 575         if (!bitmap->sb_page) { /* can't set the state */
 576                 spin_unlock_irqrestore(&bitmap->lock, flags);
 577                 return;
 578         }
 579         spin_unlock_irqrestore(&bitmap->lock, flags);
 580         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
 581         switch (op) {
 582                 case MASK_SET: sb->state |= bits;
 583                                 break;
 584                 case MASK_UNSET: sb->state &= ~bits;
 585                                 break;
 586                 default: BUG();
 587         }
 588         kunmap_atomic(sb, KM_USER0);
 589 }
 590
 591 /*
 592  * general bitmap file operations
 593  */
 594
 595 /* calculate the index of the page that contains this bit */
 596 static inline unsigned long file_page_index(unsigned long chunk)
 597 {
 598         return CHUNK_BIT_OFFSET(chunk) >> PAGE_BIT_SHIFT;
 599 }
 600
 601 /* calculate the (bit) offset of this bit within a page */
 602 static inline unsigned long file_page_offset(unsigned long chunk)
 603 {
 604         return CHUNK_BIT_OFFSET(chunk) & (PAGE_BITS - 1);
 605 }
 606
 607 /*
 608  * return a pointer to the page in the filemap that contains the given bit
 609  *
 610  * this lookup is complicated by the fact that the bitmap sb might be exactly
 611  * 1 page (e.g., x86) or less than 1 page -- so the bitmap might start on page
 612  * 0 or page 1
 613  */
 614 static inline struct page *filemap_get_page(struct bitmap *bitmap,
 615                                         unsigned long chunk)
 616 {
 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         bit = file_page_offset(chunk);
 744
 745         /* set the bit */
 746         kaddr = kmap_atomic(page, KM_USER0);
 747         if (bitmap->flags & BITMAP_HOSTENDIAN)
 748                 set_bit(bit, kaddr);
 749         else
 750                 ext2_set_bit(bit, kaddr);
 751         kunmap_atomic(kaddr, KM_USER0);
 752         PRINTK("set file bit %lu page %lu\n", bit, page->index);
 753
 754         /* record page number so it gets flushed to disk when unplug occurs */
 755         set_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 756
 757 }
 758
 759 /* this gets called when the md device is ready to unplug its underlying
 760  * (slave) device queues -- before we let any writes go down, we need to
 761  * sync the dirty pages of the bitmap file to disk */
 762 int bitmap_unplug(struct bitmap *bitmap)
 763 {
 764         unsigned long i, flags;
 765         int dirty, need_write;
 766         struct page *page;
 767         int wait = 0;
 768         int err;
 769
 770         if (!bitmap)
 771                 return 0;
 772
 773         /* look at each page to see if there are any set bits that need to be
 774          * flushed out to disk */
 775         for (i = 0; i < bitmap->file_pages; i++) {
 776                 spin_lock_irqsave(&bitmap->lock, flags);
 777                 if (!bitmap->filemap) {
 778                         spin_unlock_irqrestore(&bitmap->lock, flags);
 779                         return 0;
 780                 }
 781                 page = bitmap->filemap[i];
 782                 dirty = test_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 783                 need_write = test_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 784                 clear_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 785                 clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 786                 if (dirty)
 787                         wait = 1;
 788                 spin_unlock_irqrestore(&bitmap->lock, flags);
 789
 790                 if (dirty | need_write)
 791                         err = write_page(bitmap, page, 0);
 792         }
 793         if (wait) { /* if any writes were performed, we need to wait on them */
 794                 if (bitmap->file)
 795                         wait_event(bitmap->write_wait,
 796                                    atomic_read(&bitmap->pending_writes)==0);
 797                 else
 798                         md_super_wait(bitmap->mddev);
 799         }
 800         if (bitmap->flags & BITMAP_WRITE_ERROR)
 801                 bitmap_file_kick(bitmap);
 802         return 0;
 803 }
 804
 805 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
 806 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
 807  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
 808  * memory mapping of the bitmap file
 809  * Special cases:
 810  *   if there's no bitmap file, or if the bitmap file had been
 811  *   previously kicked from the array, we mark all the bits as
 812  *   1's in order to cause a full resync.
 813  *
 814  * We ignore all bits for sectors that end earlier than 'start'.
 815  * This is used when reading an out-of-date bitmap...
 816  */
 817 static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
 818 {
 819         unsigned long i, chunks, index, oldindex, bit;
 820         struct page *page = NULL, *oldpage = NULL;
 821         unsigned long num_pages, bit_cnt = 0;
 822         struct file *file;
 823         unsigned long bytes, offset;
 824         int outofdate;
 825         int ret = -ENOSPC;
 826         void *paddr;
 827
 828         chunks = bitmap->chunks;
 829         file = bitmap->file;
 830
 831         BUG_ON(!file && !bitmap->offset);
 832
 833 #ifdef INJECT_FAULTS_3
 834         outofdate = 1;
 835 #else
 836         outofdate = bitmap->flags & BITMAP_STALE;
 837 #endif
 838         if (outofdate)
 839                 printk(KERN_INFO "%s: bitmap file is out of date, doing full "
 840                         "recovery\n", bmname(bitmap));
 841
 842         bytes = (chunks + 7) / 8;
 843
 844         num_pages = (bytes + sizeof(bitmap_super_t) + PAGE_SIZE - 1) / PAGE_SIZE;
 845
 846         if (file && i_size_read(file->f_mapping->host) < bytes + sizeof(bitmap_super_t)) {
 847                 printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
 848                         bmname(bitmap),
 849                         (unsigned long) i_size_read(file->f_mapping->host),
 850                         bytes + sizeof(bitmap_super_t));
 851                 goto out;
 852         }
 853
 854         ret = -ENOMEM;
 855
 856         bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
 857         if (!bitmap->filemap)
 858                 goto out;
 859
 860         /* We need 4 bits per page, rounded up to a multiple of sizeof(unsigned long) */
 861         bitmap->filemap_attr = kzalloc(
 862                 (((num_pages*4/8)+sizeof(unsigned long)-1)
 863                  /sizeof(unsigned long))
 864                 *sizeof(unsigned long),
 865                 GFP_KERNEL);
 866         if (!bitmap->filemap_attr)
 867                 goto out;
 868
 869         oldindex = ~0L;
 870
 871         for (i = 0; i < chunks; i++) {
 872                 int b;
 873                 index = file_page_index(i);
 874                 bit = file_page_offset(i);
 875                 if (index != oldindex) { /* this is a new page, read it in */
 876                         int count;
 877                         /* unmap the old page, we're done with it */
 878                         if (index == num_pages-1)
 879                                 count = bytes - index * PAGE_SIZE;
 880                         else
 881                                 count = PAGE_SIZE;
 882                         if (index == 0) {
 883                                 /*
 884                                  * if we're here then the superblock page
 885                                  * contains some bits (PAGE_SIZE != sizeof sb)
 886                                  * we've already read it in, so just use it
 887                                  */
 888                                 page = bitmap->sb_page;
 889                                 offset = sizeof(bitmap_super_t);
 890                         } else if (file) {
 891                                 page = read_page(file, index, bitmap, count);
 892                                 offset = 0;
 893                         } else {
 894                                 page = read_sb_page(bitmap->mddev, bitmap->offset, index);
 895                                 offset = 0;
 896                         }
 897                         if (IS_ERR(page)) { /* read error */
 898                                 ret = PTR_ERR(page);
 899                                 goto out;
 900                         }
 901
 902                         oldindex = index;
 903                         oldpage = page;
 904
 905                         if (outofdate) {
 906                                 /*
 907                                  * if bitmap is out of date, dirty the
 908                                  * whole page and write it out
 909                                  */
 910                                 paddr = kmap_atomic(page, KM_USER0);
 911                                 memset(paddr + offset, 0xff,
 912                                        PAGE_SIZE - offset);
 913                                 kunmap_atomic(paddr, KM_USER0);
 914                                 ret = write_page(bitmap, page, 1);
 915                                 if (ret) {
 916                                         /* release, page not in filemap yet */
 917                                         put_page(page);
 918                                         goto out;
 919                                 }
 920                         }
 921
 922                         bitmap->filemap[bitmap->file_pages++] = page;
 923                 }
 924                 paddr = kmap_atomic(page, KM_USER0);
 925                 if (bitmap->flags & BITMAP_HOSTENDIAN)
 926                         b = test_bit(bit, paddr);
 927                 else
 928                         b = ext2_test_bit(bit, paddr);
 929                 kunmap_atomic(paddr, KM_USER0);
 930                 if (b) {
 931                         /* if the disk bit is set, set the memory bit */
 932                         bitmap_set_memory_bits(bitmap, i << CHUNK_BLOCK_SHIFT(bitmap),
 933                                                ((i+1) << (CHUNK_BLOCK_SHIFT(bitmap)) >= start)
 934                                 );
 935                         bit_cnt++;
 936                         set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
 937                 }
 938         }
 939
 940         /* everything went OK */
 941         ret = 0;
 942         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_UNSET);
 943
 944         if (bit_cnt) { /* Kick recovery if any bits were set */
 945                 set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
 946                 md_wakeup_thread(bitmap->mddev->thread);
 947         }
 948
 949 out:
 950         printk(KERN_INFO "%s: bitmap initialized from disk: "
 951                 "read %lu/%lu pages, set %lu bits, status: %d\n",
 952                 bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt, ret);
 953
 954         return ret;
 955 }
 956
 957 void bitmap_write_all(struct bitmap *bitmap)
 958 {
 959         /* We don't actually write all bitmap blocks here,
 960          * just flag them as needing to be written
 961          */
 962         int i;
 963
 964         for (i=0; i < bitmap->file_pages; i++)
 965                 set_page_attr(bitmap, bitmap->filemap[i],
 966                               BITMAP_PAGE_NEEDWRITE);
 967 }
 968
 969
 970 static void bitmap_count_page(struct bitmap *bitmap, sector_t offset, int inc)
 971 {
 972         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
 973         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
 974         bitmap->bp[page].count += inc;
 975 /*
 976         if (page == 0) printk("count page 0, offset %llu: %d gives %d\n",
 977                               (unsigned long long)offset, inc, bitmap->bp[page].count);
 978 */
 979         bitmap_checkfree(bitmap, page);
 980 }
 981 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
 982                                             sector_t offset, int *blocks,
 983                                             int create);
 984
 985 /*
 986  * bitmap daemon -- periodically wakes up to clean bits and flush pages
 987  *                      out to disk
 988  */
 989
 990 int bitmap_daemon_work(struct bitmap *bitmap)
 991 {
 992         unsigned long j;
 993         unsigned long flags;
 994         struct page *page = NULL, *lastpage = NULL;
 995         int err = 0;
 996         int blocks;
 997         void *paddr;
 998
 999         if (bitmap == NULL)
1000                 return 0;
1001         if (time_before(jiffies, bitmap->daemon_lastrun + bitmap->daemon_sleep*HZ))
1002                 return 0;
1003         bitmap->daemon_lastrun = jiffies;
1004
1005         for (j = 0; j < bitmap->chunks; j++) {
1006                 bitmap_counter_t *bmc;
1007                 spin_lock_irqsave(&bitmap->lock, flags);
1008                 if (!bitmap->filemap) {
1009                         /* error or shutdown */
1010                         spin_unlock_irqrestore(&bitmap->lock, flags);
1011                         break;
1012                 }
1013
1014                 page = filemap_get_page(bitmap, j);
1015
1016                 if (page != lastpage) {
1017                         /* skip this page unless it's marked as needing cleaning */
1018                         if (!test_page_attr(bitmap, page, BITMAP_PAGE_CLEAN)) {
1019                                 int need_write = test_page_attr(bitmap, page,
1020                                                                 BITMAP_PAGE_NEEDWRITE);
1021                                 if (need_write)
1022                                         clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
1023
1024                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1025                                 if (need_write) {
1026                                         switch (write_page(bitmap, page, 0)) {
1027                                         case 0:
1028                                                 break;
1029                                         default:
1030                                                 bitmap_file_kick(bitmap);
1031                                         }
1032                                 }
1033                                 continue;
1034                         }
1035
1036                         /* grab the new page, sync and release the old */
1037                         if (lastpage != NULL) {
1038                                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1039                                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1040                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1041                                         err = write_page(bitmap, lastpage, 0);
1042                                 } else {
1043                                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1044                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1045                                 }
1046                                 if (err)
1047                                         bitmap_file_kick(bitmap);
1048                         } else
1049                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1050                         lastpage = page;
1051 /*
1052                         printk("bitmap clean at page %lu\n", j);
1053 */
1054                         spin_lock_irqsave(&bitmap->lock, flags);
1055                         clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1056                 }
1057                 bmc = bitmap_get_counter(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
1058                                         &blocks, 0);
1059                 if (bmc) {
1060 /*
1061   if (j < 100) printk("bitmap: j=%lu, *bmc = 0x%x\n", j, *bmc);
1062 */
1063                         if (*bmc == 2) {
1064                                 *bmc=1; /* maybe clear the bit next time */
1065                                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1066                         } else if (*bmc == 1) {
1067                                 /* we can clear the bit */
1068                                 *bmc = 0;
1069                                 bitmap_count_page(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
1070                                                   -1);
1071
1072                                 /* clear the bit */
1073                                 paddr = kmap_atomic(page, KM_USER0);
1074                                 if (bitmap->flags & BITMAP_HOSTENDIAN)
1075                                         clear_bit(file_page_offset(j), paddr);
1076                                 else
1077                                         ext2_clear_bit(file_page_offset(j), paddr);
1078                                 kunmap_atomic(paddr, KM_USER0);
1079                         }
1080                 }
1081                 spin_unlock_irqrestore(&bitmap->lock, flags);
1082         }
1083
1084         /* now sync the final page */
1085         if (lastpage != NULL) {
1086                 spin_lock_irqsave(&bitmap->lock, flags);
1087                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1088                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1089                         spin_unlock_irqrestore(&bitmap->lock, flags);
1090                         err = write_page(bitmap, lastpage, 0);
1091                 } else {
1092                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1093                         spin_unlock_irqrestore(&bitmap->lock, flags);
1094                 }
1095         }
1096
1097         return err;
1098 }
1099
1100 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1101                                             sector_t offset, int *blocks,
1102                                             int create)
1103 {
1104         /* If 'create', we might release the lock and reclaim it.
1105          * The lock must have been taken with interrupts enabled.
1106          * If !create, we don't release the lock.
1107          */
1108         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1109         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1110         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1111         sector_t csize;
1112
1113         if (bitmap_checkpage(bitmap, page, create) < 0) {
1114                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1115                 *blocks = csize - (offset & (csize- 1));
1116                 return NULL;
1117         }
1118         /* now locked ... */
1119
1120         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1121                 /* should we use the first or second counter field
1122                  * of the hijacked pointer? */
1123                 int hi = (pageoff > PAGE_COUNTER_MASK);
1124                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap) +
1125                                           PAGE_COUNTER_SHIFT - 1);
1126                 *blocks = csize - (offset & (csize- 1));
1127                 return  &((bitmap_counter_t *)
1128                           &bitmap->bp[page].map)[hi];
1129         } else { /* page is allocated */
1130                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1131                 *blocks = csize - (offset & (csize- 1));
1132                 return (bitmap_counter_t *)
1133                         &(bitmap->bp[page].map[pageoff]);
1134         }
1135 }
1136
1137 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1138 {
1139         if (!bitmap) return 0;
1140
1141         if (behind) {
1142                 atomic_inc(&bitmap->behind_writes);
1143                 PRINTK(KERN_DEBUG "inc write-behind count %d/%d\n",
1144                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1145         }
1146
1147         while (sectors) {
1148                 int blocks;
1149                 bitmap_counter_t *bmc;
1150
1151                 spin_lock_irq(&bitmap->lock);
1152                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 1);
1153                 if (!bmc) {
1154                         spin_unlock_irq(&bitmap->lock);
1155                         return 0;
1156                 }
1157
1158                 switch(*bmc) {
1159                 case 0:
1160                         bitmap_file_set_bit(bitmap, offset);
1161                         bitmap_count_page(bitmap,offset, 1);
1162                         blk_plug_device(bitmap->mddev->queue);
1163                         /* fall through */
1164                 case 1:
1165                         *bmc = 2;
1166                 }
1167                 BUG_ON((*bmc & COUNTER_MAX) == COUNTER_MAX);
1168                 (*bmc)++;
1169
1170                 spin_unlock_irq(&bitmap->lock);
1171
1172                 offset += blocks;
1173                 if (sectors > blocks)
1174                         sectors -= blocks;
1175                 else sectors = 0;
1176         }
1177         return 0;
1178 }
1179
1180 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1181                      int success, int behind)
1182 {
1183         if (!bitmap) return;
1184         if (behind) {
1185                 atomic_dec(&bitmap->behind_writes);
1186                 PRINTK(KERN_DEBUG "dec write-behind count %d/%d\n",
1187                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1188         }
1189
1190         while (sectors) {
1191                 int blocks;
1192                 unsigned long flags;
1193                 bitmap_counter_t *bmc;
1194
1195                 spin_lock_irqsave(&bitmap->lock, flags);
1196                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 0);
1197                 if (!bmc) {
1198                         spin_unlock_irqrestore(&bitmap->lock, flags);
1199                         return;
1200                 }
1201
1202                 if (!success && ! (*bmc & NEEDED_MASK))
1203                         *bmc |= NEEDED_MASK;
1204
1205                 (*bmc)--;
1206                 if (*bmc <= 2) {
1207                         set_page_attr(bitmap,
1208                                       filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1209                                       BITMAP_PAGE_CLEAN);
1210                 }
1211                 spin_unlock_irqrestore(&bitmap->lock, flags);
1212                 offset += blocks;
1213                 if (sectors > blocks)
1214                         sectors -= blocks;
1215                 else sectors = 0;
1216         }
1217 }
1218
1219 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
1220                         int degraded)
1221 {
1222         bitmap_counter_t *bmc;
1223         int rv;
1224         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1225                 *blocks = 1024;
1226                 return 1; /* always resync if no bitmap */
1227         }
1228         spin_lock_irq(&bitmap->lock);
1229         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1230         rv = 0;
1231         if (bmc) {
1232                 /* locked */
1233                 if (RESYNC(*bmc))
1234                         rv = 1;
1235                 else if (NEEDED(*bmc)) {
1236                         rv = 1;
1237                         if (!degraded) { /* don't set/clear bits if degraded */
1238                                 *bmc |= RESYNC_MASK;
1239                                 *bmc &= ~NEEDED_MASK;
1240                         }
1241                 }
1242         }
1243         spin_unlock_irq(&bitmap->lock);
1244         return rv;
1245 }
1246
1247 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int aborted)
1248 {
1249         bitmap_counter_t *bmc;
1250         unsigned long flags;
1251 /*
1252         if (offset == 0) printk("bitmap_end_sync 0 (%d)\n", aborted);
1253 */      if (bitmap == NULL) {
1254                 *blocks = 1024;
1255                 return;
1256         }
1257         spin_lock_irqsave(&bitmap->lock, flags);
1258         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1259         if (bmc == NULL)
1260                 goto unlock;
1261         /* locked */
1262 /*
1263         if (offset == 0) printk("bitmap_end sync found 0x%x, blocks %d\n", *bmc, *blocks);
1264 */
1265         if (RESYNC(*bmc)) {
1266                 *bmc &= ~RESYNC_MASK;
1267
1268                 if (!NEEDED(*bmc) && aborted)
1269                         *bmc |= NEEDED_MASK;
1270                 else {
1271                         if (*bmc <= 2) {
1272                                 set_page_attr(bitmap,
1273                                               filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1274                                               BITMAP_PAGE_CLEAN);
1275                         }
1276                 }
1277         }
1278  unlock:
1279         spin_unlock_irqrestore(&bitmap->lock, flags);
1280 }
1281
1282 void bitmap_close_sync(struct bitmap *bitmap)
1283 {
1284         /* Sync has finished, and any bitmap chunks that weren't synced
1285          * properly have been aborted.  It remains to us to clear the
1286          * RESYNC bit wherever it is still on
1287          */
1288         sector_t sector = 0;
1289         int blocks;
1290         if (!bitmap) return;
1291         while (sector < bitmap->mddev->resync_max_sectors) {
1292                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1293 /*
1294                 if (sector < 500) printk("bitmap_close_sync: sec %llu blks %d\n",
1295                                          (unsigned long long)sector, blocks);
1296 */              sector += blocks;
1297         }
1298 }
1299
1300 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1301 {
1302         /* For each chunk covered by any of these sectors, set the
1303          * counter to 1 and set resync_needed.  They should all
1304          * be 0 at this point
1305          */
1306
1307         int secs;
1308         bitmap_counter_t *bmc;
1309         spin_lock_irq(&bitmap->lock);
1310         bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
1311         if (!bmc) {
1312                 spin_unlock_irq(&bitmap->lock);
1313                 return;
1314         }
1315         if (! *bmc) {
1316                 struct page *page;
1317                 *bmc = 1 | (needed?NEEDED_MASK:0);
1318                 bitmap_count_page(bitmap, offset, 1);
1319                 page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));
1320                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1321         }
1322         spin_unlock_irq(&bitmap->lock);
1323
1324 }
1325
1326 /*
1327  * flush out any pending updates
1328  */
1329 void bitmap_flush(mddev_t *mddev)
1330 {
1331         struct bitmap *bitmap = mddev->bitmap;
1332         int sleep;
1333
1334         if (!bitmap) /* there was no bitmap */
1335                 return;
1336
1337         /* run the daemon_work three time to ensure everything is flushed
1338          * that can be
1339          */
1340         sleep = bitmap->daemon_sleep;
1341         bitmap->daemon_sleep = 0;
1342         bitmap_daemon_work(bitmap);
1343         bitmap_daemon_work(bitmap);
1344         bitmap_daemon_work(bitmap);
1345         bitmap->daemon_sleep = sleep;
1346         bitmap_update_sb(bitmap);
1347 }
1348
1349 /*
1350  * free memory that was allocated
1351  */
1352 static void bitmap_free(struct bitmap *bitmap)
1353 {
1354         unsigned long k, pages;
1355         struct bitmap_page *bp;
1356
1357         if (!bitmap) /* there was no bitmap */
1358                 return;
1359
1360         /* release the bitmap file and kill the daemon */
1361         bitmap_file_put(bitmap);
1362
1363         bp = bitmap->bp;
1364         pages = bitmap->pages;
1365
1366         /* free all allocated memory */
1367
1368         if (bp) /* deallocate the page memory */
1369                 for (k = 0; k < pages; k++)
1370                         if (bp[k].map && !bp[k].hijacked)
1371                                 kfree(bp[k].map);
1372         kfree(bp);
1373         kfree(bitmap);
1374 }
1375 void bitmap_destroy(mddev_t *mddev)
1376 {
1377         struct bitmap *bitmap = mddev->bitmap;
1378
1379         if (!bitmap) /* there was no bitmap */
1380                 return;
1381
1382         mddev->bitmap = NULL; /* disconnect from the md device */
1383         if (mddev->thread)
1384                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1385
1386         bitmap_free(bitmap);
1387 }
1388
1389 /*
1390  * initialize the bitmap structure
1391  * if this returns an error, bitmap_destroy must be called to do clean up
1392  */
1393 int bitmap_create(mddev_t *mddev)
1394 {
1395         struct bitmap *bitmap;
1396         unsigned long blocks = mddev->resync_max_sectors;
1397         unsigned long chunks;
1398         unsigned long pages;
1399         struct file *file = mddev->bitmap_file;
1400         int err;
1401         sector_t start;
1402
1403         BUG_ON(sizeof(bitmap_super_t) != 256);
1404
1405         if (!file && !mddev->bitmap_offset) /* bitmap disabled, nothing to do */
1406                 return 0;
1407
1408         BUG_ON(file && mddev->bitmap_offset);
1409
1410         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1411         if (!bitmap)
1412                 return -ENOMEM;
1413
1414         spin_lock_init(&bitmap->lock);
1415         atomic_set(&bitmap->pending_writes, 0);
1416         init_waitqueue_head(&bitmap->write_wait);
1417
1418         bitmap->mddev = mddev;
1419
1420         bitmap->file = file;
1421         bitmap->offset = mddev->bitmap_offset;
1422         if (file) {
1423                 get_file(file);
1424                 do_sync_file_range(file, 0, LLONG_MAX,
1425                                    SYNC_FILE_RANGE_WAIT_BEFORE |
1426                                    SYNC_FILE_RANGE_WRITE |
1427                                    SYNC_FILE_RANGE_WAIT_AFTER);
1428         }
1429         /* read superblock from bitmap file (this sets bitmap->chunksize) */
1430         err = bitmap_read_sb(bitmap);
1431         if (err)
1432                 goto error;
1433
1434         bitmap->chunkshift = find_first_bit(&bitmap->chunksize,
1435                                         sizeof(bitmap->chunksize));
1436
1437         /* now that chunksize and chunkshift are set, we can use these macros */
1438         chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) /
1439                         CHUNK_BLOCK_RATIO(bitmap);
1440         pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
1441
1442         BUG_ON(!pages);
1443
1444         bitmap->chunks = chunks;
1445         bitmap->pages = pages;
1446         bitmap->missing_pages = pages;
1447         bitmap->counter_bits = COUNTER_BITS;
1448
1449         bitmap->syncchunk = ~0UL;
1450
1451 #ifdef INJECT_FATAL_FAULT_1
1452         bitmap->bp = NULL;
1453 #else
1454         bitmap->bp = kzalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
1455 #endif
1456         err = -ENOMEM;
1457         if (!bitmap->bp)
1458                 goto error;
1459
1460         /* now that we have some pages available, initialize the in-memory
1461          * bitmap from the on-disk bitmap */
1462         start = 0;
1463         if (mddev->degraded == 0
1464             || bitmap->events_cleared == mddev->events)
1465                 /* no need to keep dirty bits to optimise a re-add of a missing device */
1466                 start = mddev->recovery_cp;
1467         err = bitmap_init_from_disk(bitmap, start);
1468
1469         if (err)
1470                 goto error;
1471
1472         printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
1473                 pages, bmname(bitmap));
1474
1475         mddev->bitmap = bitmap;
1476
1477         mddev->thread->timeout = bitmap->daemon_sleep * HZ;
1478
1479         return bitmap_update_sb(bitmap);
1480
1481  error:
1482         bitmap_free(bitmap);
1483         return err;
1484 }
1485
1486 /* the bitmap API -- for raid personalities */
1487 EXPORT_SYMBOL(bitmap_startwrite);
1488 EXPORT_SYMBOL(bitmap_endwrite);
1489 EXPORT_SYMBOL(bitmap_start_sync);
1490 EXPORT_SYMBOL(bitmap_end_sync);
1491 EXPORT_SYMBOL(bitmap_unplug);
1492 EXPORT_SYMBOL(bitmap_close_sync);