drivers/md/bitmap.c

   1 /*
   2  * bitmap.c two-level bitmap (C) Peter T. Breuer (ptb@ot.uc3m.es) 2003
   3  *
   4  * bitmap_create  - sets up the bitmap structure
   5  * bitmap_destroy - destroys the bitmap structure
   6  *
   7  * additions, Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.:
   8  * - added disk storage for bitmap
   9  * - changes to allow various bitmap chunk sizes
  10  */
  11
  12 /*
  13  * Still to do:
  14  *
  15  * flush after percent set rather than just time based. (maybe both).
  16  * wait if count gets too high, wake when it drops to half.
  17  */
  18
  19 #include <linux/module.h>
  20 #include <linux/errno.h>
  21 #include <linux/slab.h>
  22 #include <linux/init.h>
  23 #include <linux/timer.h>
  24 #include <linux/sched.h>
  25 #include <linux/list.h>
  26 #include <linux/file.h>
  27 #include <linux/mount.h>
  28 #include <linux/buffer_head.h>
  29 #include <linux/raid/md.h>
  30 #include <linux/raid/bitmap.h>
  31
  32 /* debug macros */
  33
  34 #define DEBUG 0
  35
  36 #if DEBUG
  37 /* these are for debugging purposes only! */
  38
  39 /* define one and only one of these */
  40 #define INJECT_FAULTS_1 0 /* cause bitmap_alloc_page to fail always */
  41 #define INJECT_FAULTS_2 0 /* cause bitmap file to be kicked when first bit set*/
  42 #define INJECT_FAULTS_3 0 /* treat bitmap file as kicked at init time */
  43 #define INJECT_FAULTS_4 0 /* undef */
  44 #define INJECT_FAULTS_5 0 /* undef */
  45 #define INJECT_FAULTS_6 0
  46
  47 /* if these are defined, the driver will fail! debug only */
  48 #define INJECT_FATAL_FAULT_1 0 /* fail kmalloc, causing bitmap_create to fail */
  49 #define INJECT_FATAL_FAULT_2 0 /* undef */
  50 #define INJECT_FATAL_FAULT_3 0 /* undef */
  51 #endif
  52
  53 //#define DPRINTK PRINTK /* set this NULL to avoid verbose debug output */
  54 #define DPRINTK(x...) do { } while(0)
  55
  56 #ifndef PRINTK
  57 #  if DEBUG > 0
  58 #    define PRINTK(x...) printk(KERN_DEBUG x)
  59 #  else
  60 #    define PRINTK(x...)
  61 #  endif
  62 #endif
  63
  64 static inline char * bmname(struct bitmap *bitmap)
  65 {
  66         return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
  67 }
  68
  69
  70 /*
  71  * just a placeholder - calls kmalloc for bitmap pages
  72  */
  73 static unsigned char *bitmap_alloc_page(struct bitmap *bitmap)
  74 {
  75         unsigned char *page;
  76
  77 #ifdef INJECT_FAULTS_1
  78         page = NULL;
  79 #else
  80         page = kmalloc(PAGE_SIZE, GFP_NOIO);
  81 #endif
  82         if (!page)
  83                 printk("%s: bitmap_alloc_page FAILED\n", bmname(bitmap));
  84         else
  85                 PRINTK("%s: bitmap_alloc_page: allocated page at %p\n",
  86                         bmname(bitmap), page);
  87         return page;
  88 }
  89
  90 /*
  91  * for now just a placeholder -- just calls kfree for bitmap pages
  92  */
  93 static void bitmap_free_page(struct bitmap *bitmap, unsigned char *page)
  94 {
  95         PRINTK("%s: bitmap_free_page: free page %p\n", bmname(bitmap), page);
  96         kfree(page);
  97 }
  98
  99 /*
 100  * check a page and, if necessary, allocate it (or hijack it if the alloc fails)
 101  *
 102  * 1) check to see if this page is allocated, if it's not then try to alloc
 103  * 2) if the alloc fails, set the page's hijacked flag so we'll use the
 104  *    page pointer directly as a counter
 105  *
 106  * if we find our page, we increment the page's refcount so that it stays
 107  * allocated while we're using it
 108  */
 109 static int bitmap_checkpage(struct bitmap *bitmap, unsigned long page, int create)
 110 {
 111         unsigned char *mappage;
 112
 113         if (page >= bitmap->pages) {
 114                 printk(KERN_ALERT
 115                         "%s: invalid bitmap page request: %lu (> %lu)\n",
 116                         bmname(bitmap), page, bitmap->pages-1);
 117                 return -EINVAL;
 118         }
 119
 120
 121         if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
 122                 return 0;
 123
 124         if (bitmap->bp[page].map) /* page is already allocated, just return */
 125                 return 0;
 126
 127         if (!create)
 128                 return -ENOENT;
 129
 130         spin_unlock_irq(&bitmap->lock);
 131
 132         /* this page has not been allocated yet */
 133
 134         if ((mappage = bitmap_alloc_page(bitmap)) == NULL) {
 135                 PRINTK("%s: bitmap map page allocation failed, hijacking\n",
 136                         bmname(bitmap));
 137                 /* failed - set the hijacked flag so that we can use the
 138                  * pointer as a counter */
 139                 spin_lock_irq(&bitmap->lock);
 140                 if (!bitmap->bp[page].map)
 141                         bitmap->bp[page].hijacked = 1;
 142                 goto out;
 143         }
 144
 145         /* got a page */
 146
 147         spin_lock_irq(&bitmap->lock);
 148
 149         /* recheck the page */
 150
 151         if (bitmap->bp[page].map || bitmap->bp[page].hijacked) {
 152                 /* somebody beat us to getting the page */
 153                 bitmap_free_page(bitmap, mappage);
 154                 return 0;
 155         }
 156
 157         /* no page was in place and we have one, so install it */
 158
 159         memset(mappage, 0, PAGE_SIZE);
 160         bitmap->bp[page].map = mappage;
 161         bitmap->missing_pages--;
 162 out:
 163         return 0;
 164 }
 165
 166
 167 /* if page is completely empty, put it back on the free list, or dealloc it */
 168 /* if page was hijacked, unmark the flag so it might get alloced next time */
 169 /* Note: lock should be held when calling this */
 170 static void bitmap_checkfree(struct bitmap *bitmap, unsigned long page)
 171 {
 172         char *ptr;
 173
 174         if (bitmap->bp[page].count) /* page is still busy */
 175                 return;
 176
 177         /* page is no longer in use, it can be released */
 178
 179         if (bitmap->bp[page].hijacked) { /* page was hijacked, undo this now */
 180                 bitmap->bp[page].hijacked = 0;
 181                 bitmap->bp[page].map = NULL;
 182                 return;
 183         }
 184
 185         /* normal case, free the page */
 186
 187 #if 0
 188 /* actually ... let's not.  We will probably need the page again exactly when
 189  * memory is tight and we are flusing to disk
 190  */
 191         return;
 192 #else
 193         ptr = bitmap->bp[page].map;
 194         bitmap->bp[page].map = NULL;
 195         bitmap->missing_pages++;
 196         bitmap_free_page(bitmap, ptr);
 197         return;
 198 #endif
 199 }
 200
 201
 202 /*
 203  * bitmap file handling - read and write the bitmap file and its superblock
 204  */
 205
 206 /* copy the pathname of a file to a buffer */
 207 char *file_path(struct file *file, char *buf, int count)
 208 {
 209         struct dentry *d;
 210         struct vfsmount *v;
 211
 212         if (!buf)
 213                 return NULL;
 214
 215         d = file->f_path.dentry;
 216         v = file->f_path.mnt;
 217
 218         buf = d_path(d, v, buf, count);
 219
 220         return IS_ERR(buf) ? NULL : buf;
 221 }
 222
 223 /*
 224  * basic page I/O operations
 225  */
 226
 227 /* IO operations when bitmap is stored near all superblocks */
 228 static struct page *read_sb_page(mddev_t *mddev, long offset, unsigned long index)
 229 {
 230         /* choose a good rdev and read the page from there */
 231
 232         mdk_rdev_t *rdev;
 233         struct list_head *tmp;
 234         struct page *page = alloc_page(GFP_KERNEL);
 235         sector_t target;
 236
 237         if (!page)
 238                 return ERR_PTR(-ENOMEM);
 239
 240         ITERATE_RDEV(mddev, rdev, tmp) {
 241                 if (! test_bit(In_sync, &rdev->flags)
 242                     || test_bit(Faulty, &rdev->flags))
 243                         continue;
 244
 245                 target = (rdev->sb_offset << 1) + offset + index * (PAGE_SIZE/512);
 246
 247                 if (sync_page_io(rdev->bdev, target, PAGE_SIZE, page, READ)) {
 248                         page->index = index;
 249                         attach_page_buffers(page, NULL); /* so that free_buffer will
 250                                                           * quietly no-op */
 251                         return page;
 252                 }
 253         }
 254         return ERR_PTR(-EIO);
 255
 256 }
 257
 258 static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
 259 {
 260         mdk_rdev_t *rdev;
 261         struct list_head *tmp;
 262         mddev_t *mddev = bitmap->mddev;
 263
 264         ITERATE_RDEV(mddev, rdev, tmp)
 265                 if (test_bit(In_sync, &rdev->flags)
 266                     && !test_bit(Faulty, &rdev->flags)) {
 267                         int size = PAGE_SIZE;
 268                         if (page->index == bitmap->file_pages-1)
 269                                 size = roundup(bitmap->last_page_size,
 270                                                bdev_hardsect_size(rdev->bdev));
 271                         md_super_write(mddev, rdev,
 272                                        (rdev->sb_offset<<1) + bitmap->offset
 273                                        + page->index * (PAGE_SIZE/512),
 274                                        size,
 275                                        page);
 276                 }
 277
 278         if (wait)
 279                 md_super_wait(mddev);
 280         return 0;
 281 }
 282
 283 /*
 284  * write out a page to a file
 285  */
 286 static int write_page(struct bitmap *bitmap, struct page *page, int wait)
 287 {
 288         struct buffer_head *bh;
 289
 290         if (bitmap->file == NULL)
 291                 return write_sb_page(bitmap, page, wait);
 292
 293         bh = page_buffers(page);
 294
 295         while (bh && bh->b_blocknr) {
 296                 atomic_inc(&bitmap->pending_writes);
 297                 set_buffer_locked(bh);
 298                 set_buffer_mapped(bh);
 299                 submit_bh(WRITE, bh);
 300                 bh = bh->b_this_page;
 301         }
 302
 303         if (wait) {
 304                 wait_event(bitmap->write_wait,
 305                            atomic_read(&bitmap->pending_writes)==0);
 306                 return (bitmap->flags & BITMAP_WRITE_ERROR) ? -EIO : 0;
 307         }
 308         return 0;
 309 }
 310
 311 static void end_bitmap_write(struct buffer_head *bh, int uptodate)
 312 {
 313         struct bitmap *bitmap = bh->b_private;
 314         unsigned long flags;
 315
 316         if (!uptodate) {
 317                 spin_lock_irqsave(&bitmap->lock, flags);
 318                 bitmap->flags |= BITMAP_WRITE_ERROR;
 319                 spin_unlock_irqrestore(&bitmap->lock, flags);
 320         }
 321         if (atomic_dec_and_test(&bitmap->pending_writes))
 322                 wake_up(&bitmap->write_wait);
 323 }
 324
 325 /* copied from buffer.c */
 326 static void
 327 __clear_page_buffers(struct page *page)
 328 {
 329         ClearPagePrivate(page);
 330         set_page_private(page, 0);
 331         page_cache_release(page);
 332 }
 333 static void free_buffers(struct page *page)
 334 {
 335         struct buffer_head *bh = page_buffers(page);
 336
 337         while (bh) {
 338                 struct buffer_head *next = bh->b_this_page;
 339                 free_buffer_head(bh);
 340                 bh = next;
 341         }
 342         __clear_page_buffers(page);
 343         put_page(page);
 344 }
 345
 346 /* read a page from a file.
 347  * We both read the page, and attach buffers to the page to record the
 348  * address of each block (using bmap).  These addresses will be used
 349  * to write the block later, completely bypassing the filesystem.
 350  * This usage is similar to how swap files are handled, and allows us
 351  * to write to a file with no concerns of memory allocation failing.
 352  */
 353 static struct page *read_page(struct file *file, unsigned long index,
 354                               struct bitmap *bitmap,
 355                               unsigned long count)
 356 {
 357         struct page *page = NULL;
 358         struct inode *inode = file->f_path.dentry->d_inode;
 359         struct buffer_head *bh;
 360         sector_t block;
 361
 362         PRINTK("read bitmap file (%dB @ %Lu)\n", (int)PAGE_SIZE,
 363                         (unsigned long long)index << PAGE_SHIFT);
 364
 365         page = alloc_page(GFP_KERNEL);
 366         if (!page)
 367                 page = ERR_PTR(-ENOMEM);
 368         if (IS_ERR(page))
 369                 goto out;
 370
 371         bh = alloc_page_buffers(page, 1<<inode->i_blkbits, 0);
 372         if (!bh) {
 373                 put_page(page);
 374                 page = ERR_PTR(-ENOMEM);
 375                 goto out;
 376         }
 377         attach_page_buffers(page, bh);
 378         block = index << (PAGE_SHIFT - inode->i_blkbits);
 379         while (bh) {
 380                 if (count == 0)
 381                         bh->b_blocknr = 0;
 382                 else {
 383                         bh->b_blocknr = bmap(inode, block);
 384                         if (bh->b_blocknr == 0) {
 385                                 /* Cannot use this file! */
 386                                 free_buffers(page);
 387                                 page = ERR_PTR(-EINVAL);
 388                                 goto out;
 389                         }
 390                         bh->b_bdev = inode->i_sb->s_bdev;
 391                         if (count < (1<<inode->i_blkbits))
 392                                 count = 0;
 393                         else
 394                                 count -= (1<<inode->i_blkbits);
 395
 396                         bh->b_end_io = end_bitmap_write;
 397                         bh->b_private = bitmap;
 398                         atomic_inc(&bitmap->pending_writes);
 399                         set_buffer_locked(bh);
 400                         set_buffer_mapped(bh);
 401                         submit_bh(READ, bh);
 402                 }
 403                 block++;
 404                 bh = bh->b_this_page;
 405         }
 406         page->index = index;
 407
 408         wait_event(bitmap->write_wait,
 409                    atomic_read(&bitmap->pending_writes)==0);
 410         if (bitmap->flags & BITMAP_WRITE_ERROR) {
 411                 free_buffers(page);
 412                 page = ERR_PTR(-EIO);
 413         }
 414 out:
 415         if (IS_ERR(page))
 416                 printk(KERN_ALERT "md: bitmap read error: (%dB @ %Lu): %ld\n",
 417                         (int)PAGE_SIZE,
 418                         (unsigned long long)index << PAGE_SHIFT,
 419                         PTR_ERR(page));
 420         return page;
 421 }
 422
 423 /*
 424  * bitmap file superblock operations
 425  */
 426
 427 /* update the event counter and sync the superblock to disk */
 428 int bitmap_update_sb(struct bitmap *bitmap)
 429 {
 430         bitmap_super_t *sb;
 431         unsigned long flags;
 432
 433         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
 434                 return 0;
 435         spin_lock_irqsave(&bitmap->lock, flags);
 436         if (!bitmap->sb_page) { /* no superblock */
 437                 spin_unlock_irqrestore(&bitmap->lock, flags);
 438                 return 0;
 439         }
 440         spin_unlock_irqrestore(&bitmap->lock, flags);
 441         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
 442         sb->events = cpu_to_le64(bitmap->mddev->events);
 443         if (!bitmap->mddev->degraded)
 444                 sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
 445         kunmap_atomic(sb, KM_USER0);
 446         return write_page(bitmap, bitmap->sb_page, 1);
 447 }
 448
 449 /* print out the bitmap file superblock */
 450 void bitmap_print_sb(struct bitmap *bitmap)
 451 {
 452         bitmap_super_t *sb;
 453
 454         if (!bitmap || !bitmap->sb_page)
 455                 return;
 456         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
 457         printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
 458         printk(KERN_DEBUG "         magic: %08x\n", le32_to_cpu(sb->magic));
 459         printk(KERN_DEBUG "       version: %d\n", le32_to_cpu(sb->version));
 460         printk(KERN_DEBUG "          uuid: %08x.%08x.%08x.%08x\n",
 461                                         *(__u32 *)(sb->uuid+0),
 462                                         *(__u32 *)(sb->uuid+4),
 463                                         *(__u32 *)(sb->uuid+8),
 464                                         *(__u32 *)(sb->uuid+12));
 465         printk(KERN_DEBUG "        events: %llu\n",
 466                         (unsigned long long) le64_to_cpu(sb->events));
 467         printk(KERN_DEBUG "events cleared: %llu\n",
 468                         (unsigned long long) le64_to_cpu(sb->events_cleared));
 469         printk(KERN_DEBUG "         state: %08x\n", le32_to_cpu(sb->state));
 470         printk(KERN_DEBUG "     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
 471         printk(KERN_DEBUG "  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
 472         printk(KERN_DEBUG "     sync size: %llu KB\n",
 473                         (unsigned long long)le64_to_cpu(sb->sync_size)/2);
 474         printk(KERN_DEBUG "max write behind: %d\n", le32_to_cpu(sb->write_behind));
 475         kunmap_atomic(sb, KM_USER0);
 476 }
 477
 478 /* read the superblock from the bitmap file and initialize some bitmap fields */
 479 static int bitmap_read_sb(struct bitmap *bitmap)
 480 {
 481         char *reason = NULL;
 482         bitmap_super_t *sb;
 483         unsigned long chunksize, daemon_sleep, write_behind;
 484         unsigned long long events;
 485         int err = -EINVAL;
 486
 487         /* page 0 is the superblock, read it... */
 488         if (bitmap->file) {
 489                 loff_t isize = i_size_read(bitmap->file->f_mapping->host);
 490                 int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
 491
 492                 bitmap->sb_page = read_page(bitmap->file, 0, bitmap, bytes);
 493         } else {
 494                 bitmap->sb_page = read_sb_page(bitmap->mddev, bitmap->offset, 0);
 495         }
 496         if (IS_ERR(bitmap->sb_page)) {
 497                 err = PTR_ERR(bitmap->sb_page);
 498                 bitmap->sb_page = NULL;
 499                 return err;
 500         }
 501
 502         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
 503
 504         chunksize = le32_to_cpu(sb->chunksize);
 505         daemon_sleep = le32_to_cpu(sb->daemon_sleep);
 506         write_behind = le32_to_cpu(sb->write_behind);
 507
 508         /* verify that the bitmap-specific fields are valid */
 509         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
 510                 reason = "bad magic";
 511         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
 512                  le32_to_cpu(sb->version) > BITMAP_MAJOR_HI)
 513                 reason = "unrecognized superblock version";
 514         else if (chunksize < PAGE_SIZE)
 515                 reason = "bitmap chunksize too small";
 516         else if ((1 << ffz(~chunksize)) != chunksize)
 517                 reason = "bitmap chunksize not a power of 2";
 518         else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT / HZ)
 519                 reason = "daemon sleep period out of range";
 520         else if (write_behind > COUNTER_MAX)
 521                 reason = "write-behind limit out of range (0 - 16383)";
 522         if (reason) {
 523                 printk(KERN_INFO "%s: invalid bitmap file superblock: %s\n",
 524                         bmname(bitmap), reason);
 525                 goto out;
 526         }
 527
 528         /* keep the array size field of the bitmap superblock up to date */
 529         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 530
 531         if (!bitmap->mddev->persistent)
 532                 goto success;
 533
 534         /*
 535          * if we have a persistent array superblock, compare the
 536          * bitmap's UUID and event counter to the mddev's
 537          */
 538         if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
 539                 printk(KERN_INFO "%s: bitmap superblock UUID mismatch\n",
 540                         bmname(bitmap));
 541                 goto out;
 542         }
 543         events = le64_to_cpu(sb->events);
 544         if (events < bitmap->mddev->events) {
 545                 printk(KERN_INFO "%s: bitmap file is out of date (%llu < %llu) "
 546                         "-- forcing full recovery\n", bmname(bitmap), events,
 547                         (unsigned long long) bitmap->mddev->events);
 548                 sb->state |= cpu_to_le32(BITMAP_STALE);
 549         }
 550 success:
 551         /* assign fields using values from superblock */
 552         bitmap->chunksize = chunksize;
 553         bitmap->daemon_sleep = daemon_sleep;
 554         bitmap->daemon_lastrun = jiffies;
 555         bitmap->max_write_behind = write_behind;
 556         bitmap->flags |= le32_to_cpu(sb->state);
 557         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
 558                 bitmap->flags |= BITMAP_HOSTENDIAN;
 559         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
 560         if (sb->state & cpu_to_le32(BITMAP_STALE))
 561                 bitmap->events_cleared = bitmap->mddev->events;
 562         err = 0;
 563 out:
 564         kunmap_atomic(sb, KM_USER0);
 565         if (err)
 566                 bitmap_print_sb(bitmap);
 567         return err;
 568 }
 569
 570 enum bitmap_mask_op {
 571         MASK_SET,
 572         MASK_UNSET
 573 };
 574
 575 /* record the state of the bitmap in the superblock */
 576 static void bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
 577                                 enum bitmap_mask_op op)
 578 {
 579         bitmap_super_t *sb;
 580         unsigned long flags;
 581
 582         spin_lock_irqsave(&bitmap->lock, flags);
 583         if (!bitmap->sb_page) { /* can't set the state */
 584                 spin_unlock_irqrestore(&bitmap->lock, flags);
 585                 return;
 586         }
 587         spin_unlock_irqrestore(&bitmap->lock, flags);
 588         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
 589         switch (op) {
 590                 case MASK_SET: sb->state |= cpu_to_le32(bits);
 591                                 break;
 592                 case MASK_UNSET: sb->state &= cpu_to_le32(~bits);
 593                                 break;
 594                 default: BUG();
 595         }
 596         kunmap_atomic(sb, KM_USER0);
 597 }
 598
 599 /*
 600  * general bitmap file operations
 601  */
 602
 603 /* calculate the index of the page that contains this bit */
 604 static inline unsigned long file_page_index(unsigned long chunk)
 605 {
 606         return CHUNK_BIT_OFFSET(chunk) >> PAGE_BIT_SHIFT;
 607 }
 608
 609 /* calculate the (bit) offset of this bit within a page */
 610 static inline unsigned long file_page_offset(unsigned long chunk)
 611 {
 612         return CHUNK_BIT_OFFSET(chunk) & (PAGE_BITS - 1);
 613 }
 614
 615 /*
 616  * return a pointer to the page in the filemap that contains the given bit
 617  *
 618  * this lookup is complicated by the fact that the bitmap sb might be exactly
 619  * 1 page (e.g., x86) or less than 1 page -- so the bitmap might start on page
 620  * 0 or page 1
 621  */
 622 static inline struct page *filemap_get_page(struct bitmap *bitmap,
 623                                         unsigned long chunk)
 624 {
 625         if (file_page_index(chunk) >= bitmap->file_pages) return NULL;
 626         return bitmap->filemap[file_page_index(chunk) - file_page_index(0)];
 627 }
 628
 629
 630 static void bitmap_file_unmap(struct bitmap *bitmap)
 631 {
 632         struct page **map, *sb_page;
 633         unsigned long *attr;
 634         int pages;
 635         unsigned long flags;
 636
 637         spin_lock_irqsave(&bitmap->lock, flags);
 638         map = bitmap->filemap;
 639         bitmap->filemap = NULL;
 640         attr = bitmap->filemap_attr;
 641         bitmap->filemap_attr = NULL;
 642         pages = bitmap->file_pages;
 643         bitmap->file_pages = 0;
 644         sb_page = bitmap->sb_page;
 645         bitmap->sb_page = NULL;
 646         spin_unlock_irqrestore(&bitmap->lock, flags);
 647
 648         while (pages--)
 649                 if (map[pages]->index != 0) /* 0 is sb_page, release it below */
 650                         free_buffers(map[pages]);
 651         kfree(map);
 652         kfree(attr);
 653
 654         if (sb_page)
 655                 free_buffers(sb_page);
 656 }
 657
 658 static void bitmap_file_put(struct bitmap *bitmap)
 659 {
 660         struct file *file;
 661         unsigned long flags;
 662
 663         spin_lock_irqsave(&bitmap->lock, flags);
 664         file = bitmap->file;
 665         bitmap->file = NULL;
 666         spin_unlock_irqrestore(&bitmap->lock, flags);
 667
 668         if (file)
 669                 wait_event(bitmap->write_wait,
 670                            atomic_read(&bitmap->pending_writes)==0);
 671         bitmap_file_unmap(bitmap);
 672
 673         if (file) {
 674                 struct inode *inode = file->f_path.dentry->d_inode;
 675                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
 676                 fput(file);
 677         }
 678 }
 679
 680
 681 /*
 682  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
 683  * then it is no longer reliable, so we stop using it and we mark the file
 684  * as failed in the superblock
 685  */
 686 static void bitmap_file_kick(struct bitmap *bitmap)
 687 {
 688         char *path, *ptr = NULL;
 689
 690         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET);
 691         bitmap_update_sb(bitmap);
 692
 693         if (bitmap->file) {
 694                 path = kmalloc(PAGE_SIZE, GFP_KERNEL);
 695                 if (path)
 696                         ptr = file_path(bitmap->file, path, PAGE_SIZE);
 697
 698                 printk(KERN_ALERT "%s: kicking failed bitmap file %s from array!\n",
 699                        bmname(bitmap), ptr ? ptr : "");
 700
 701                 kfree(path);
 702         }
 703
 704         bitmap_file_put(bitmap);
 705
 706         return;
 707 }
 708
 709 enum bitmap_page_attr {
 710         BITMAP_PAGE_DIRTY = 0, // there are set bits that need to be synced
 711         BITMAP_PAGE_CLEAN = 1, // there are bits that might need to be cleared
 712         BITMAP_PAGE_NEEDWRITE=2, // there are cleared bits that need to be synced
 713 };
 714
 715 static inline void set_page_attr(struct bitmap *bitmap, struct page *page,
 716                                 enum bitmap_page_attr attr)
 717 {
 718         __set_bit((page->index<<2) + attr, bitmap->filemap_attr);
 719 }
 720
 721 static inline void clear_page_attr(struct bitmap *bitmap, struct page *page,
 722                                 enum bitmap_page_attr attr)
 723 {
 724         __clear_bit((page->index<<2) + attr, bitmap->filemap_attr);
 725 }
 726
 727 static inline unsigned long test_page_attr(struct bitmap *bitmap, struct page *page,
 728                                            enum bitmap_page_attr attr)
 729 {
 730         return test_bit((page->index<<2) + attr, bitmap->filemap_attr);
 731 }
 732
 733 /*
 734  * bitmap_file_set_bit -- called before performing a write to the md device
 735  * to set (and eventually sync) a particular bit in the bitmap file
 736  *
 737  * we set the bit immediately, then we record the page number so that
 738  * when an unplug occurs, we can flush the dirty pages out to disk
 739  */
 740 static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 741 {
 742         unsigned long bit;
 743         struct page *page;
 744         void *kaddr;
 745         unsigned long chunk = block >> CHUNK_BLOCK_SHIFT(bitmap);
 746
 747         if (!bitmap->filemap) {
 748                 return;
 749         }
 750
 751         page = filemap_get_page(bitmap, chunk);
 752         if (!page) return;
 753         bit = file_page_offset(chunk);
 754
 755         /* set the bit */
 756         kaddr = kmap_atomic(page, KM_USER0);
 757         if (bitmap->flags & BITMAP_HOSTENDIAN)
 758                 set_bit(bit, kaddr);
 759         else
 760                 ext2_set_bit(bit, kaddr);
 761         kunmap_atomic(kaddr, KM_USER0);
 762         PRINTK("set file bit %lu page %lu\n", bit, page->index);
 763
 764         /* record page number so it gets flushed to disk when unplug occurs */
 765         set_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 766
 767 }
 768
 769 /* this gets called when the md device is ready to unplug its underlying
 770  * (slave) device queues -- before we let any writes go down, we need to
 771  * sync the dirty pages of the bitmap file to disk */
 772 int bitmap_unplug(struct bitmap *bitmap)
 773 {
 774         unsigned long i, flags;
 775         int dirty, need_write;
 776         struct page *page;
 777         int wait = 0;
 778         int err;
 779
 780         if (!bitmap)
 781                 return 0;
 782
 783         /* look at each page to see if there are any set bits that need to be
 784          * flushed out to disk */
 785         for (i = 0; i < bitmap->file_pages; i++) {
 786                 spin_lock_irqsave(&bitmap->lock, flags);
 787                 if (!bitmap->filemap) {
 788                         spin_unlock_irqrestore(&bitmap->lock, flags);
 789                         return 0;
 790                 }
 791                 page = bitmap->filemap[i];
 792                 dirty = test_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 793                 need_write = test_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 794                 clear_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 795                 clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 796                 if (dirty)
 797                         wait = 1;
 798                 spin_unlock_irqrestore(&bitmap->lock, flags);
 799
 800                 if (dirty | need_write)
 801                         err = write_page(bitmap, page, 0);
 802         }
 803         if (wait) { /* if any writes were performed, we need to wait on them */
 804                 if (bitmap->file)
 805                         wait_event(bitmap->write_wait,
 806                                    atomic_read(&bitmap->pending_writes)==0);
 807                 else
 808                         md_super_wait(bitmap->mddev);
 809         }
 810         if (bitmap->flags & BITMAP_WRITE_ERROR)
 811                 bitmap_file_kick(bitmap);
 812         return 0;
 813 }
 814
 815 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
 816 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
 817  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
 818  * memory mapping of the bitmap file
 819  * Special cases:
 820  *   if there's no bitmap file, or if the bitmap file had been
 821  *   previously kicked from the array, we mark all the bits as
 822  *   1's in order to cause a full resync.
 823  *
 824  * We ignore all bits for sectors that end earlier than 'start'.
 825  * This is used when reading an out-of-date bitmap...
 826  */
 827 static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
 828 {
 829         unsigned long i, chunks, index, oldindex, bit;
 830         struct page *page = NULL, *oldpage = NULL;
 831         unsigned long num_pages, bit_cnt = 0;
 832         struct file *file;
 833         unsigned long bytes, offset;
 834         int outofdate;
 835         int ret = -ENOSPC;
 836         void *paddr;
 837
 838         chunks = bitmap->chunks;
 839         file = bitmap->file;
 840
 841         BUG_ON(!file && !bitmap->offset);
 842
 843 #ifdef INJECT_FAULTS_3
 844         outofdate = 1;
 845 #else
 846         outofdate = bitmap->flags & BITMAP_STALE;
 847 #endif
 848         if (outofdate)
 849                 printk(KERN_INFO "%s: bitmap file is out of date, doing full "
 850                         "recovery\n", bmname(bitmap));
 851
 852         bytes = (chunks + 7) / 8;
 853
 854         num_pages = (bytes + sizeof(bitmap_super_t) + PAGE_SIZE - 1) / PAGE_SIZE;
 855
 856         if (file && i_size_read(file->f_mapping->host) < bytes + sizeof(bitmap_super_t)) {
 857                 printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
 858                         bmname(bitmap),
 859                         (unsigned long) i_size_read(file->f_mapping->host),
 860                         bytes + sizeof(bitmap_super_t));
 861                 goto out;
 862         }
 863
 864         ret = -ENOMEM;
 865
 866         bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
 867         if (!bitmap->filemap)
 868                 goto out;
 869
 870         /* We need 4 bits per page, rounded up to a multiple of sizeof(unsigned long) */
 871         bitmap->filemap_attr = kzalloc(
 872                 roundup( DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
 873                 GFP_KERNEL);
 874         if (!bitmap->filemap_attr)
 875                 goto out;
 876
 877         oldindex = ~0L;
 878
 879         for (i = 0; i < chunks; i++) {
 880                 int b;
 881                 index = file_page_index(i);
 882                 bit = file_page_offset(i);
 883                 if (index != oldindex) { /* this is a new page, read it in */
 884                         int count;
 885                         /* unmap the old page, we're done with it */
 886                         if (index == num_pages-1)
 887                                 count = bytes + sizeof(bitmap_super_t)
 888                                         - index * PAGE_SIZE;
 889                         else
 890                                 count = PAGE_SIZE;
 891                         if (index == 0) {
 892                                 /*
 893                                  * if we're here then the superblock page
 894                                  * contains some bits (PAGE_SIZE != sizeof sb)
 895                                  * we've already read it in, so just use it
 896                                  */
 897                                 page = bitmap->sb_page;
 898                                 offset = sizeof(bitmap_super_t);
 899                         } else if (file) {
 900                                 page = read_page(file, index, bitmap, count);
 901                                 offset = 0;
 902                         } else {
 903                                 page = read_sb_page(bitmap->mddev, bitmap->offset, index);
 904                                 offset = 0;
 905                         }
 906                         if (IS_ERR(page)) { /* read error */
 907                                 ret = PTR_ERR(page);
 908                                 goto out;
 909                         }
 910
 911                         oldindex = index;
 912                         oldpage = page;
 913
 914                         if (outofdate) {
 915                                 /*
 916                                  * if bitmap is out of date, dirty the
 917                                  * whole page and write it out
 918                                  */
 919                                 paddr = kmap_atomic(page, KM_USER0);
 920                                 memset(paddr + offset, 0xff,
 921                                        PAGE_SIZE - offset);
 922                                 kunmap_atomic(paddr, KM_USER0);
 923                                 ret = write_page(bitmap, page, 1);
 924                                 if (ret) {
 925                                         /* release, page not in filemap yet */
 926                                         put_page(page);
 927                                         goto out;
 928                                 }
 929                         }
 930
 931                         bitmap->filemap[bitmap->file_pages++] = page;
 932                         bitmap->last_page_size = count;
 933                 }
 934                 paddr = kmap_atomic(page, KM_USER0);
 935                 if (bitmap->flags & BITMAP_HOSTENDIAN)
 936                         b = test_bit(bit, paddr);
 937                 else
 938                         b = ext2_test_bit(bit, paddr);
 939                 kunmap_atomic(paddr, KM_USER0);
 940                 if (b) {
 941                         /* if the disk bit is set, set the memory bit */
 942                         bitmap_set_memory_bits(bitmap, i << CHUNK_BLOCK_SHIFT(bitmap),
 943                                                ((i+1) << (CHUNK_BLOCK_SHIFT(bitmap)) >= start)
 944                                 );
 945                         bit_cnt++;
 946                         set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
 947                 }
 948         }
 949
 950         /* everything went OK */
 951         ret = 0;
 952         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_UNSET);
 953
 954         if (bit_cnt) { /* Kick recovery if any bits were set */
 955                 set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
 956                 md_wakeup_thread(bitmap->mddev->thread);
 957         }
 958
 959 out:
 960         printk(KERN_INFO "%s: bitmap initialized from disk: "
 961                 "read %lu/%lu pages, set %lu bits, status: %d\n",
 962                 bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt, ret);
 963
 964         return ret;
 965 }
 966
 967 void bitmap_write_all(struct bitmap *bitmap)
 968 {
 969         /* We don't actually write all bitmap blocks here,
 970          * just flag them as needing to be written
 971          */
 972         int i;
 973
 974         for (i=0; i < bitmap->file_pages; i++)
 975                 set_page_attr(bitmap, bitmap->filemap[i],
 976                               BITMAP_PAGE_NEEDWRITE);
 977 }
 978
 979
 980 static void bitmap_count_page(struct bitmap *bitmap, sector_t offset, int inc)
 981 {
 982         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
 983         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
 984         bitmap->bp[page].count += inc;
 985 /*
 986         if (page == 0) printk("count page 0, offset %llu: %d gives %d\n",
 987                               (unsigned long long)offset, inc, bitmap->bp[page].count);
 988 */
 989         bitmap_checkfree(bitmap, page);
 990 }
 991 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
 992                                             sector_t offset, int *blocks,
 993                                             int create);
 994
 995 /*
 996  * bitmap daemon -- periodically wakes up to clean bits and flush pages
 997  *                      out to disk
 998  */
 999
1000 int bitmap_daemon_work(struct bitmap *bitmap)
1001 {
1002         unsigned long j;
1003         unsigned long flags;
1004         struct page *page = NULL, *lastpage = NULL;
1005         int err = 0;
1006         int blocks;
1007         void *paddr;
1008
1009         if (bitmap == NULL)
1010                 return 0;
1011         if (time_before(jiffies, bitmap->daemon_lastrun + bitmap->daemon_sleep*HZ))
1012                 return 0;
1013         bitmap->daemon_lastrun = jiffies;
1014
1015         for (j = 0; j < bitmap->chunks; j++) {
1016                 bitmap_counter_t *bmc;
1017                 spin_lock_irqsave(&bitmap->lock, flags);
1018                 if (!bitmap->filemap) {
1019                         /* error or shutdown */
1020                         spin_unlock_irqrestore(&bitmap->lock, flags);
1021                         break;
1022                 }
1023
1024                 page = filemap_get_page(bitmap, j);
1025
1026                 if (page != lastpage) {
1027                         /* skip this page unless it's marked as needing cleaning */
1028                         if (!test_page_attr(bitmap, page, BITMAP_PAGE_CLEAN)) {
1029                                 int need_write = test_page_attr(bitmap, page,
1030                                                                 BITMAP_PAGE_NEEDWRITE);
1031                                 if (need_write)
1032                                         clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
1033
1034                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1035                                 if (need_write) {
1036                                         switch (write_page(bitmap, page, 0)) {
1037                                         case 0:
1038                                                 break;
1039                                         default:
1040                                                 bitmap_file_kick(bitmap);
1041                                         }
1042                                 }
1043                                 continue;
1044                         }
1045
1046                         /* grab the new page, sync and release the old */
1047                         if (lastpage != NULL) {
1048                                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1049                                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1050                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1051                                         err = write_page(bitmap, lastpage, 0);
1052                                 } else {
1053                                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1054                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1055                                 }
1056                                 if (err)
1057                                         bitmap_file_kick(bitmap);
1058                         } else
1059                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1060                         lastpage = page;
1061 /*
1062                         printk("bitmap clean at page %lu\n", j);
1063 */
1064                         spin_lock_irqsave(&bitmap->lock, flags);
1065                         clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1066                 }
1067                 bmc = bitmap_get_counter(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
1068                                         &blocks, 0);
1069                 if (bmc) {
1070 /*
1071   if (j < 100) printk("bitmap: j=%lu, *bmc = 0x%x\n", j, *bmc);
1072 */
1073                         if (*bmc == 2) {
1074                                 *bmc=1; /* maybe clear the bit next time */
1075                                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1076                         } else if (*bmc == 1) {
1077                                 /* we can clear the bit */
1078                                 *bmc = 0;
1079                                 bitmap_count_page(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
1080                                                   -1);
1081
1082                                 /* clear the bit */
1083                                 paddr = kmap_atomic(page, KM_USER0);
1084                                 if (bitmap->flags & BITMAP_HOSTENDIAN)
1085                                         clear_bit(file_page_offset(j), paddr);
1086                                 else
1087                                         ext2_clear_bit(file_page_offset(j), paddr);
1088                                 kunmap_atomic(paddr, KM_USER0);
1089                         }
1090                 }
1091                 spin_unlock_irqrestore(&bitmap->lock, flags);
1092         }
1093
1094         /* now sync the final page */
1095         if (lastpage != NULL) {
1096                 spin_lock_irqsave(&bitmap->lock, flags);
1097                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1098                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1099                         spin_unlock_irqrestore(&bitmap->lock, flags);
1100                         err = write_page(bitmap, lastpage, 0);
1101                 } else {
1102                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1103                         spin_unlock_irqrestore(&bitmap->lock, flags);
1104                 }
1105         }
1106
1107         return err;
1108 }
1109
1110 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1111                                             sector_t offset, int *blocks,
1112                                             int create)
1113 {
1114         /* If 'create', we might release the lock and reclaim it.
1115          * The lock must have been taken with interrupts enabled.
1116          * If !create, we don't release the lock.
1117          */
1118         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1119         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1120         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1121         sector_t csize;
1122
1123         if (bitmap_checkpage(bitmap, page, create) < 0) {
1124                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1125                 *blocks = csize - (offset & (csize- 1));
1126                 return NULL;
1127         }
1128         /* now locked ... */
1129
1130         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1131                 /* should we use the first or second counter field
1132                  * of the hijacked pointer? */
1133                 int hi = (pageoff > PAGE_COUNTER_MASK);
1134                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap) +
1135                                           PAGE_COUNTER_SHIFT - 1);
1136                 *blocks = csize - (offset & (csize- 1));
1137                 return  &((bitmap_counter_t *)
1138                           &bitmap->bp[page].map)[hi];
1139         } else { /* page is allocated */
1140                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1141                 *blocks = csize - (offset & (csize- 1));
1142                 return (bitmap_counter_t *)
1143                         &(bitmap->bp[page].map[pageoff]);
1144         }
1145 }
1146
1147 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1148 {
1149         if (!bitmap) return 0;
1150
1151         if (behind) {
1152                 atomic_inc(&bitmap->behind_writes);
1153                 PRINTK(KERN_DEBUG "inc write-behind count %d/%d\n",
1154                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1155         }
1156
1157         while (sectors) {
1158                 int blocks;
1159                 bitmap_counter_t *bmc;
1160
1161                 spin_lock_irq(&bitmap->lock);
1162                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 1);
1163                 if (!bmc) {
1164                         spin_unlock_irq(&bitmap->lock);
1165                         return 0;
1166                 }
1167
1168                 if (unlikely((*bmc & COUNTER_MAX) == COUNTER_MAX)) {
1169                         DEFINE_WAIT(__wait);
1170                         /* note that it is safe to do the prepare_to_wait
1171                          * after the test as long as we do it before dropping
1172                          * the spinlock.
1173                          */
1174                         prepare_to_wait(&bitmap->overflow_wait, &__wait,
1175                                         TASK_UNINTERRUPTIBLE);
1176                         spin_unlock_irq(&bitmap->lock);
1177                         bitmap->mddev->queue
1178                                 ->unplug_fn(bitmap->mddev->queue);
1179                         schedule();
1180                         finish_wait(&bitmap->overflow_wait, &__wait);
1181                         continue;
1182                 }
1183
1184                 switch(*bmc) {
1185                 case 0:
1186                         bitmap_file_set_bit(bitmap, offset);
1187                         bitmap_count_page(bitmap,offset, 1);
1188                         blk_plug_device(bitmap->mddev->queue);
1189                         /* fall through */
1190                 case 1:
1191                         *bmc = 2;
1192                 }
1193
1194                 (*bmc)++;
1195
1196                 spin_unlock_irq(&bitmap->lock);
1197
1198                 offset += blocks;
1199                 if (sectors > blocks)
1200                         sectors -= blocks;
1201                 else sectors = 0;
1202         }
1203         return 0;
1204 }
1205
1206 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1207                      int success, int behind)
1208 {
1209         if (!bitmap) return;
1210         if (behind) {
1211                 atomic_dec(&bitmap->behind_writes);
1212                 PRINTK(KERN_DEBUG "dec write-behind count %d/%d\n",
1213                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1214         }
1215
1216         while (sectors) {
1217                 int blocks;
1218                 unsigned long flags;
1219                 bitmap_counter_t *bmc;
1220
1221                 spin_lock_irqsave(&bitmap->lock, flags);
1222                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 0);
1223                 if (!bmc) {
1224                         spin_unlock_irqrestore(&bitmap->lock, flags);
1225                         return;
1226                 }
1227
1228                 if (!success && ! (*bmc & NEEDED_MASK))
1229                         *bmc |= NEEDED_MASK;
1230
1231                 if ((*bmc & COUNTER_MAX) == COUNTER_MAX)
1232                         wake_up(&bitmap->overflow_wait);
1233
1234                 (*bmc)--;
1235                 if (*bmc <= 2) {
1236                         set_page_attr(bitmap,
1237                                       filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1238                                       BITMAP_PAGE_CLEAN);
1239                 }
1240                 spin_unlock_irqrestore(&bitmap->lock, flags);
1241                 offset += blocks;
1242                 if (sectors > blocks)
1243                         sectors -= blocks;
1244                 else sectors = 0;
1245         }
1246 }
1247
1248 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
1249                         int degraded)
1250 {
1251         bitmap_counter_t *bmc;
1252         int rv;
1253         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1254                 *blocks = 1024;
1255                 return 1; /* always resync if no bitmap */
1256         }
1257         spin_lock_irq(&bitmap->lock);
1258         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1259         rv = 0;
1260         if (bmc) {
1261                 /* locked */
1262                 if (RESYNC(*bmc))
1263                         rv = 1;
1264                 else if (NEEDED(*bmc)) {
1265                         rv = 1;
1266                         if (!degraded) { /* don't set/clear bits if degraded */
1267                                 *bmc |= RESYNC_MASK;
1268                                 *bmc &= ~NEEDED_MASK;
1269                         }
1270                 }
1271         }
1272         spin_unlock_irq(&bitmap->lock);
1273         return rv;
1274 }
1275
1276 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int aborted)
1277 {
1278         bitmap_counter_t *bmc;
1279         unsigned long flags;
1280 /*
1281         if (offset == 0) printk("bitmap_end_sync 0 (%d)\n", aborted);
1282 */      if (bitmap == NULL) {
1283                 *blocks = 1024;
1284                 return;
1285         }
1286         spin_lock_irqsave(&bitmap->lock, flags);
1287         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1288         if (bmc == NULL)
1289                 goto unlock;
1290         /* locked */
1291 /*
1292         if (offset == 0) printk("bitmap_end sync found 0x%x, blocks %d\n", *bmc, *blocks);
1293 */
1294         if (RESYNC(*bmc)) {
1295                 *bmc &= ~RESYNC_MASK;
1296
1297                 if (!NEEDED(*bmc) && aborted)
1298                         *bmc |= NEEDED_MASK;
1299                 else {
1300                         if (*bmc <= 2) {
1301                                 set_page_attr(bitmap,
1302                                               filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1303                                               BITMAP_PAGE_CLEAN);
1304                         }
1305                 }
1306         }
1307  unlock:
1308         spin_unlock_irqrestore(&bitmap->lock, flags);
1309 }
1310
1311 void bitmap_close_sync(struct bitmap *bitmap)
1312 {
1313         /* Sync has finished, and any bitmap chunks that weren't synced
1314          * properly have been aborted.  It remains to us to clear the
1315          * RESYNC bit wherever it is still on
1316          */
1317         sector_t sector = 0;
1318         int blocks;
1319         if (!bitmap) return;
1320         while (sector < bitmap->mddev->resync_max_sectors) {
1321                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1322 /*
1323                 if (sector < 500) printk("bitmap_close_sync: sec %llu blks %d\n",
1324                                          (unsigned long long)sector, blocks);
1325 */              sector += blocks;
1326         }
1327 }
1328
1329 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1330 {
1331         /* For each chunk covered by any of these sectors, set the
1332          * counter to 1 and set resync_needed.  They should all
1333          * be 0 at this point
1334          */
1335
1336         int secs;
1337         bitmap_counter_t *bmc;
1338         spin_lock_irq(&bitmap->lock);
1339         bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
1340         if (!bmc) {
1341                 spin_unlock_irq(&bitmap->lock);
1342                 return;
1343         }
1344         if (! *bmc) {
1345                 struct page *page;
1346                 *bmc = 1 | (needed?NEEDED_MASK:0);
1347                 bitmap_count_page(bitmap, offset, 1);
1348                 page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));
1349                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1350         }
1351         spin_unlock_irq(&bitmap->lock);
1352
1353 }
1354
1355 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
1356 void bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1357 {
1358         unsigned long chunk;
1359
1360         for (chunk = s; chunk <= e; chunk++) {
1361                 sector_t sec = chunk << CHUNK_BLOCK_SHIFT(bitmap);
1362                 bitmap_set_memory_bits(bitmap, sec, 1);
1363                 bitmap_file_set_bit(bitmap, sec);
1364         }
1365 }
1366
1367 /*
1368  * flush out any pending updates
1369  */
1370 void bitmap_flush(mddev_t *mddev)
1371 {
1372         struct bitmap *bitmap = mddev->bitmap;
1373         int sleep;
1374
1375         if (!bitmap) /* there was no bitmap */
1376                 return;
1377
1378         /* run the daemon_work three time to ensure everything is flushed
1379          * that can be
1380          */
1381         sleep = bitmap->daemon_sleep;
1382         bitmap->daemon_sleep = 0;
1383         bitmap_daemon_work(bitmap);
1384         bitmap_daemon_work(bitmap);
1385         bitmap_daemon_work(bitmap);
1386         bitmap->daemon_sleep = sleep;
1387         bitmap_update_sb(bitmap);
1388 }
1389
1390 /*
1391  * free memory that was allocated
1392  */
1393 static void bitmap_free(struct bitmap *bitmap)
1394 {
1395         unsigned long k, pages;
1396         struct bitmap_page *bp;
1397
1398         if (!bitmap) /* there was no bitmap */
1399                 return;
1400
1401         /* release the bitmap file and kill the daemon */
1402         bitmap_file_put(bitmap);
1403
1404         bp = bitmap->bp;
1405         pages = bitmap->pages;
1406
1407         /* free all allocated memory */
1408
1409         if (bp) /* deallocate the page memory */
1410                 for (k = 0; k < pages; k++)
1411                         if (bp[k].map && !bp[k].hijacked)
1412                                 kfree(bp[k].map);
1413         kfree(bp);
1414         kfree(bitmap);
1415 }
1416 void bitmap_destroy(mddev_t *mddev)
1417 {
1418         struct bitmap *bitmap = mddev->bitmap;
1419
1420         if (!bitmap) /* there was no bitmap */
1421                 return;
1422
1423         mddev->bitmap = NULL; /* disconnect from the md device */
1424         if (mddev->thread)
1425                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1426
1427         bitmap_free(bitmap);
1428 }
1429
1430 /*
1431  * initialize the bitmap structure
1432  * if this returns an error, bitmap_destroy must be called to do clean up
1433  */
1434 int bitmap_create(mddev_t *mddev)
1435 {
1436         struct bitmap *bitmap;
1437         unsigned long blocks = mddev->resync_max_sectors;
1438         unsigned long chunks;
1439         unsigned long pages;
1440         struct file *file = mddev->bitmap_file;
1441         int err;
1442         sector_t start;
1443
1444         BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
1445
1446         if (!file && !mddev->bitmap_offset) /* bitmap disabled, nothing to do */
1447                 return 0;
1448
1449         BUG_ON(file && mddev->bitmap_offset);
1450
1451         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1452         if (!bitmap)
1453                 return -ENOMEM;
1454
1455         spin_lock_init(&bitmap->lock);
1456         atomic_set(&bitmap->pending_writes, 0);
1457         init_waitqueue_head(&bitmap->write_wait);
1458         init_waitqueue_head(&bitmap->overflow_wait);
1459
1460         bitmap->mddev = mddev;
1461
1462         bitmap->file = file;
1463         bitmap->offset = mddev->bitmap_offset;
1464         if (file) {
1465                 get_file(file);
1466                 do_sync_mapping_range(file->f_mapping, 0, LLONG_MAX,
1467                                       SYNC_FILE_RANGE_WAIT_BEFORE |
1468                                       SYNC_FILE_RANGE_WRITE |
1469                                       SYNC_FILE_RANGE_WAIT_AFTER);
1470         }
1471         /* read superblock from bitmap file (this sets bitmap->chunksize) */
1472         err = bitmap_read_sb(bitmap);
1473         if (err)
1474                 goto error;
1475
1476         bitmap->chunkshift = ffz(~bitmap->chunksize);
1477
1478         /* now that chunksize and chunkshift are set, we can use these macros */
1479         chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) /
1480                         CHUNK_BLOCK_RATIO(bitmap);
1481         pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
1482
1483         BUG_ON(!pages);
1484
1485         bitmap->chunks = chunks;
1486         bitmap->pages = pages;
1487         bitmap->missing_pages = pages;
1488         bitmap->counter_bits = COUNTER_BITS;
1489
1490         bitmap->syncchunk = ~0UL;
1491
1492 #ifdef INJECT_FATAL_FAULT_1
1493         bitmap->bp = NULL;
1494 #else
1495         bitmap->bp = kzalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
1496 #endif
1497         err = -ENOMEM;
1498         if (!bitmap->bp)
1499                 goto error;
1500
1501         /* now that we have some pages available, initialize the in-memory
1502          * bitmap from the on-disk bitmap */
1503         start = 0;
1504         if (mddev->degraded == 0
1505             || bitmap->events_cleared == mddev->events)
1506                 /* no need to keep dirty bits to optimise a re-add of a missing device */
1507                 start = mddev->recovery_cp;
1508         err = bitmap_init_from_disk(bitmap, start);
1509
1510         if (err)
1511                 goto error;
1512
1513         printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
1514                 pages, bmname(bitmap));
1515
1516         mddev->bitmap = bitmap;
1517
1518         mddev->thread->timeout = bitmap->daemon_sleep * HZ;
1519
1520         return bitmap_update_sb(bitmap);
1521
1522  error:
1523         bitmap_free(bitmap);
1524         return err;
1525 }
1526
1527 /* the bitmap API -- for raid personalities */
1528 EXPORT_SYMBOL(bitmap_startwrite);
1529 EXPORT_SYMBOL(bitmap_endwrite);
1530 EXPORT_SYMBOL(bitmap_start_sync);
1531 EXPORT_SYMBOL(bitmap_end_sync);
1532 EXPORT_SYMBOL(bitmap_unplug);
1533 EXPORT_SYMBOL(bitmap_close_sync);