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  */
  17
  18 #include <linux/blkdev.h>
  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/seq_file.h>
  30 #include "md.h"
  31 #include "bitmap.h"
  32
  33 static inline char *bmname(struct bitmap *bitmap)
  34 {
  35         return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
  36 }
  37
  38 /*
  39  * check a page and, if necessary, allocate it (or hijack it if the alloc fails)
  40  *
  41  * 1) check to see if this page is allocated, if it's not then try to alloc
  42  * 2) if the alloc fails, set the page's hijacked flag so we'll use the
  43  *    page pointer directly as a counter
  44  *
  45  * if we find our page, we increment the page's refcount so that it stays
  46  * allocated while we're using it
  47  */
  48 static int bitmap_checkpage(struct bitmap *bitmap,
  49                             unsigned long page, int create)
  50 __releases(bitmap->lock)
  51 __acquires(bitmap->lock)
  52 {
  53         unsigned char *mappage;
  54
  55         if (page >= bitmap->pages) {
  56                 /* This can happen if bitmap_start_sync goes beyond
  57                  * End-of-device while looking for a whole page.
  58                  * It is harmless.
  59                  */
  60                 return -EINVAL;
  61         }
  62
  63         if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
  64                 return 0;
  65
  66         if (bitmap->bp[page].map) /* page is already allocated, just return */
  67                 return 0;
  68
  69         if (!create)
  70                 return -ENOENT;
  71
  72         /* this page has not been allocated yet */
  73
  74         spin_unlock_irq(&bitmap->lock);
  75         mappage = kzalloc(PAGE_SIZE, GFP_NOIO);
  76         spin_lock_irq(&bitmap->lock);
  77
  78         if (mappage == NULL) {
  79                 pr_debug("%s: bitmap map page allocation failed, hijacking\n",
  80                          bmname(bitmap));
  81                 /* failed - set the hijacked flag so that we can use the
  82                  * pointer as a counter */
  83                 if (!bitmap->bp[page].map)
  84                         bitmap->bp[page].hijacked = 1;
  85         } else if (bitmap->bp[page].map ||
  86                    bitmap->bp[page].hijacked) {
  87                 /* somebody beat us to getting the page */
  88                 kfree(mappage);
  89                 return 0;
  90         } else {
  91
  92                 /* no page was in place and we have one, so install it */
  93
  94                 bitmap->bp[page].map = mappage;
  95                 bitmap->missing_pages--;
  96         }
  97         return 0;
  98 }
  99
 100 /* if page is completely empty, put it back on the free list, or dealloc it */
 101 /* if page was hijacked, unmark the flag so it might get alloced next time */
 102 /* Note: lock should be held when calling this */
 103 static void bitmap_checkfree(struct bitmap *bitmap, unsigned long page)
 104 {
 105         char *ptr;
 106
 107         if (bitmap->bp[page].count) /* page is still busy */
 108                 return;
 109
 110         /* page is no longer in use, it can be released */
 111
 112         if (bitmap->bp[page].hijacked) { /* page was hijacked, undo this now */
 113                 bitmap->bp[page].hijacked = 0;
 114                 bitmap->bp[page].map = NULL;
 115         } else {
 116                 /* normal case, free the page */
 117                 ptr = bitmap->bp[page].map;
 118                 bitmap->bp[page].map = NULL;
 119                 bitmap->missing_pages++;
 120                 kfree(ptr);
 121         }
 122 }
 123
 124 /*
 125  * bitmap file handling - read and write the bitmap file and its superblock
 126  */
 127
 128 /*
 129  * basic page I/O operations
 130  */
 131
 132 /* IO operations when bitmap is stored near all superblocks */
 133 static struct page *read_sb_page(struct mddev *mddev, loff_t offset,
 134                                  struct page *page,
 135                                  unsigned long index, int size)
 136 {
 137         /* choose a good rdev and read the page from there */
 138
 139         struct md_rdev *rdev;
 140         sector_t target;
 141         int did_alloc = 0;
 142
 143         if (!page) {
 144                 page = alloc_page(GFP_KERNEL);
 145                 if (!page)
 146                         return ERR_PTR(-ENOMEM);
 147                 did_alloc = 1;
 148         }
 149
 150         rdev_for_each(rdev, mddev) {
 151                 if (! test_bit(In_sync, &rdev->flags)
 152                     || test_bit(Faulty, &rdev->flags))
 153                         continue;
 154
 155                 target = offset + index * (PAGE_SIZE/512);
 156
 157                 if (sync_page_io(rdev, target,
 158                                  roundup(size, bdev_logical_block_size(rdev->bdev)),
 159                                  page, READ, true)) {
 160                         page->index = index;
 161                         attach_page_buffers(page, NULL); /* so that free_buffer will
 162                                                           * quietly no-op */
 163                         return page;
 164                 }
 165         }
 166         if (did_alloc)
 167                 put_page(page);
 168         return ERR_PTR(-EIO);
 169
 170 }
 171
 172 static struct md_rdev *next_active_rdev(struct md_rdev *rdev, struct mddev *mddev)
 173 {
 174         /* Iterate the disks of an mddev, using rcu to protect access to the
 175          * linked list, and raising the refcount of devices we return to ensure
 176          * they don't disappear while in use.
 177          * As devices are only added or removed when raid_disk is < 0 and
 178          * nr_pending is 0 and In_sync is clear, the entries we return will
 179          * still be in the same position on the list when we re-enter
 180          * list_for_each_continue_rcu.
 181          */
 182         struct list_head *pos;
 183         rcu_read_lock();
 184         if (rdev == NULL)
 185                 /* start at the beginning */
 186                 pos = &mddev->disks;
 187         else {
 188                 /* release the previous rdev and start from there. */
 189                 rdev_dec_pending(rdev, mddev);
 190                 pos = &rdev->same_set;
 191         }
 192         list_for_each_continue_rcu(pos, &mddev->disks) {
 193                 rdev = list_entry(pos, struct md_rdev, same_set);
 194                 if (rdev->raid_disk >= 0 &&
 195                     !test_bit(Faulty, &rdev->flags)) {
 196                         /* this is a usable devices */
 197                         atomic_inc(&rdev->nr_pending);
 198                         rcu_read_unlock();
 199                         return rdev;
 200                 }
 201         }
 202         rcu_read_unlock();
 203         return NULL;
 204 }
 205
 206 static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
 207 {
 208         struct md_rdev *rdev = NULL;
 209         struct block_device *bdev;
 210         struct mddev *mddev = bitmap->mddev;
 211
 212         while ((rdev = next_active_rdev(rdev, mddev)) != NULL) {
 213                 int size = PAGE_SIZE;
 214                 loff_t offset = mddev->bitmap_info.offset;
 215
 216                 bdev = (rdev->meta_bdev) ? rdev->meta_bdev : rdev->bdev;
 217
 218                 if (page->index == bitmap->file_pages-1)
 219                         size = roundup(bitmap->last_page_size,
 220                                        bdev_logical_block_size(bdev));
 221                 /* Just make sure we aren't corrupting data or
 222                  * metadata
 223                  */
 224                 if (mddev->external) {
 225                         /* Bitmap could be anywhere. */
 226                         if (rdev->sb_start + offset + (page->index
 227                                                        * (PAGE_SIZE/512))
 228                             > rdev->data_offset
 229                             &&
 230                             rdev->sb_start + offset
 231                             < (rdev->data_offset + mddev->dev_sectors
 232                              + (PAGE_SIZE/512)))
 233                                 goto bad_alignment;
 234                 } else if (offset < 0) {
 235                         /* DATA  BITMAP METADATA  */
 236                         if (offset
 237                             + (long)(page->index * (PAGE_SIZE/512))
 238                             + size/512 > 0)
 239                                 /* bitmap runs in to metadata */
 240                                 goto bad_alignment;
 241                         if (rdev->data_offset + mddev->dev_sectors
 242                             > rdev->sb_start + offset)
 243                                 /* data runs in to bitmap */
 244                                 goto bad_alignment;
 245                 } else if (rdev->sb_start < rdev->data_offset) {
 246                         /* METADATA BITMAP DATA */
 247                         if (rdev->sb_start
 248                             + offset
 249                             + page->index*(PAGE_SIZE/512) + size/512
 250                             > rdev->data_offset)
 251                                 /* bitmap runs in to data */
 252                                 goto bad_alignment;
 253                 } else {
 254                         /* DATA METADATA BITMAP - no problems */
 255                 }
 256                 md_super_write(mddev, rdev,
 257                                rdev->sb_start + offset
 258                                + page->index * (PAGE_SIZE/512),
 259                                size,
 260                                page);
 261         }
 262
 263         if (wait)
 264                 md_super_wait(mddev);
 265         return 0;
 266
 267  bad_alignment:
 268         return -EINVAL;
 269 }
 270
 271 static void bitmap_file_kick(struct bitmap *bitmap);
 272 /*
 273  * write out a page to a file
 274  */
 275 static void write_page(struct bitmap *bitmap, struct page *page, int wait)
 276 {
 277         struct buffer_head *bh;
 278
 279         if (bitmap->file == NULL) {
 280                 switch (write_sb_page(bitmap, page, wait)) {
 281                 case -EINVAL:
 282                         bitmap->flags |= BITMAP_WRITE_ERROR;
 283                 }
 284         } else {
 285
 286                 bh = page_buffers(page);
 287
 288                 while (bh && bh->b_blocknr) {
 289                         atomic_inc(&bitmap->pending_writes);
 290                         set_buffer_locked(bh);
 291                         set_buffer_mapped(bh);
 292                         submit_bh(WRITE | REQ_SYNC, bh);
 293                         bh = bh->b_this_page;
 294                 }
 295
 296                 if (wait)
 297                         wait_event(bitmap->write_wait,
 298                                    atomic_read(&bitmap->pending_writes)==0);
 299         }
 300         if (bitmap->flags & BITMAP_WRITE_ERROR)
 301                 bitmap_file_kick(bitmap);
 302 }
 303
 304 static void end_bitmap_write(struct buffer_head *bh, int uptodate)
 305 {
 306         struct bitmap *bitmap = bh->b_private;
 307         unsigned long flags;
 308
 309         if (!uptodate) {
 310                 spin_lock_irqsave(&bitmap->lock, flags);
 311                 bitmap->flags |= BITMAP_WRITE_ERROR;
 312                 spin_unlock_irqrestore(&bitmap->lock, flags);
 313         }
 314         if (atomic_dec_and_test(&bitmap->pending_writes))
 315                 wake_up(&bitmap->write_wait);
 316 }
 317
 318 /* copied from buffer.c */
 319 static void
 320 __clear_page_buffers(struct page *page)
 321 {
 322         ClearPagePrivate(page);
 323         set_page_private(page, 0);
 324         page_cache_release(page);
 325 }
 326 static void free_buffers(struct page *page)
 327 {
 328         struct buffer_head *bh = page_buffers(page);
 329
 330         while (bh) {
 331                 struct buffer_head *next = bh->b_this_page;
 332                 free_buffer_head(bh);
 333                 bh = next;
 334         }
 335         __clear_page_buffers(page);
 336         put_page(page);
 337 }
 338
 339 /* read a page from a file.
 340  * We both read the page, and attach buffers to the page to record the
 341  * address of each block (using bmap).  These addresses will be used
 342  * to write the block later, completely bypassing the filesystem.
 343  * This usage is similar to how swap files are handled, and allows us
 344  * to write to a file with no concerns of memory allocation failing.
 345  */
 346 static struct page *read_page(struct file *file, unsigned long index,
 347                               struct bitmap *bitmap,
 348                               unsigned long count)
 349 {
 350         struct page *page = NULL;
 351         struct inode *inode = file->f_path.dentry->d_inode;
 352         struct buffer_head *bh;
 353         sector_t block;
 354
 355         pr_debug("read bitmap file (%dB @ %llu)\n", (int)PAGE_SIZE,
 356                  (unsigned long long)index << PAGE_SHIFT);
 357
 358         page = alloc_page(GFP_KERNEL);
 359         if (!page)
 360                 page = ERR_PTR(-ENOMEM);
 361         if (IS_ERR(page))
 362                 goto out;
 363
 364         bh = alloc_page_buffers(page, 1<<inode->i_blkbits, 0);
 365         if (!bh) {
 366                 put_page(page);
 367                 page = ERR_PTR(-ENOMEM);
 368                 goto out;
 369         }
 370         attach_page_buffers(page, bh);
 371         block = index << (PAGE_SHIFT - inode->i_blkbits);
 372         while (bh) {
 373                 if (count == 0)
 374                         bh->b_blocknr = 0;
 375                 else {
 376                         bh->b_blocknr = bmap(inode, block);
 377                         if (bh->b_blocknr == 0) {
 378                                 /* Cannot use this file! */
 379                                 free_buffers(page);
 380                                 page = ERR_PTR(-EINVAL);
 381                                 goto out;
 382                         }
 383                         bh->b_bdev = inode->i_sb->s_bdev;
 384                         if (count < (1<<inode->i_blkbits))
 385                                 count = 0;
 386                         else
 387                                 count -= (1<<inode->i_blkbits);
 388
 389                         bh->b_end_io = end_bitmap_write;
 390                         bh->b_private = bitmap;
 391                         atomic_inc(&bitmap->pending_writes);
 392                         set_buffer_locked(bh);
 393                         set_buffer_mapped(bh);
 394                         submit_bh(READ, bh);
 395                 }
 396                 block++;
 397                 bh = bh->b_this_page;
 398         }
 399         page->index = index;
 400
 401         wait_event(bitmap->write_wait,
 402                    atomic_read(&bitmap->pending_writes)==0);
 403         if (bitmap->flags & BITMAP_WRITE_ERROR) {
 404                 free_buffers(page);
 405                 page = ERR_PTR(-EIO);
 406         }
 407 out:
 408         if (IS_ERR(page))
 409                 printk(KERN_ALERT "md: bitmap read error: (%dB @ %llu): %ld\n",
 410                         (int)PAGE_SIZE,
 411                         (unsigned long long)index << PAGE_SHIFT,
 412                         PTR_ERR(page));
 413         return page;
 414 }
 415
 416 /*
 417  * bitmap file superblock operations
 418  */
 419
 420 /* update the event counter and sync the superblock to disk */
 421 void bitmap_update_sb(struct bitmap *bitmap)
 422 {
 423         bitmap_super_t *sb;
 424
 425         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
 426                 return;
 427         if (bitmap->mddev->bitmap_info.external)
 428                 return;
 429         if (!bitmap->sb_page) /* no superblock */
 430                 return;
 431         sb = kmap_atomic(bitmap->sb_page);
 432         sb->events = cpu_to_le64(bitmap->mddev->events);
 433         if (bitmap->mddev->events < bitmap->events_cleared)
 434                 /* rocking back to read-only */
 435                 bitmap->events_cleared = bitmap->mddev->events;
 436         sb->events_cleared = cpu_to_le64(bitmap->events_cleared);
 437         sb->state = cpu_to_le32(bitmap->flags);
 438         /* Just in case these have been changed via sysfs: */
 439         sb->daemon_sleep = cpu_to_le32(bitmap->mddev->bitmap_info.daemon_sleep/HZ);
 440         sb->write_behind = cpu_to_le32(bitmap->mddev->bitmap_info.max_write_behind);
 441         kunmap_atomic(sb);
 442         write_page(bitmap, bitmap->sb_page, 1);
 443 }
 444
 445 /* print out the bitmap file superblock */
 446 void bitmap_print_sb(struct bitmap *bitmap)
 447 {
 448         bitmap_super_t *sb;
 449
 450         if (!bitmap || !bitmap->sb_page)
 451                 return;
 452         sb = kmap_atomic(bitmap->sb_page);
 453         printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
 454         printk(KERN_DEBUG "         magic: %08x\n", le32_to_cpu(sb->magic));
 455         printk(KERN_DEBUG "       version: %d\n", le32_to_cpu(sb->version));
 456         printk(KERN_DEBUG "          uuid: %08x.%08x.%08x.%08x\n",
 457                                         *(__u32 *)(sb->uuid+0),
 458                                         *(__u32 *)(sb->uuid+4),
 459                                         *(__u32 *)(sb->uuid+8),
 460                                         *(__u32 *)(sb->uuid+12));
 461         printk(KERN_DEBUG "        events: %llu\n",
 462                         (unsigned long long) le64_to_cpu(sb->events));
 463         printk(KERN_DEBUG "events cleared: %llu\n",
 464                         (unsigned long long) le64_to_cpu(sb->events_cleared));
 465         printk(KERN_DEBUG "         state: %08x\n", le32_to_cpu(sb->state));
 466         printk(KERN_DEBUG "     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
 467         printk(KERN_DEBUG "  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
 468         printk(KERN_DEBUG "     sync size: %llu KB\n",
 469                         (unsigned long long)le64_to_cpu(sb->sync_size)/2);
 470         printk(KERN_DEBUG "max write behind: %d\n", le32_to_cpu(sb->write_behind));
 471         kunmap_atomic(sb);
 472 }
 473
 474 /*
 475  * bitmap_new_disk_sb
 476  * @bitmap
 477  *
 478  * This function is somewhat the reverse of bitmap_read_sb.  bitmap_read_sb
 479  * reads and verifies the on-disk bitmap superblock and populates bitmap_info.
 480  * This function verifies 'bitmap_info' and populates the on-disk bitmap
 481  * structure, which is to be written to disk.
 482  *
 483  * Returns: 0 on success, -Exxx on error
 484  */
 485 static int bitmap_new_disk_sb(struct bitmap *bitmap)
 486 {
 487         bitmap_super_t *sb;
 488         unsigned long chunksize, daemon_sleep, write_behind;
 489         int err = -EINVAL;
 490
 491         bitmap->sb_page = alloc_page(GFP_KERNEL);
 492         if (IS_ERR(bitmap->sb_page)) {
 493                 err = PTR_ERR(bitmap->sb_page);
 494                 bitmap->sb_page = NULL;
 495                 return err;
 496         }
 497         bitmap->sb_page->index = 0;
 498
 499         sb = kmap_atomic(bitmap->sb_page);
 500
 501         sb->magic = cpu_to_le32(BITMAP_MAGIC);
 502         sb->version = cpu_to_le32(BITMAP_MAJOR_HI);
 503
 504         chunksize = bitmap->mddev->bitmap_info.chunksize;
 505         BUG_ON(!chunksize);
 506         if (!is_power_of_2(chunksize)) {
 507                 kunmap_atomic(sb);
 508                 printk(KERN_ERR "bitmap chunksize not a power of 2\n");
 509                 return -EINVAL;
 510         }
 511         sb->chunksize = cpu_to_le32(chunksize);
 512
 513         daemon_sleep = bitmap->mddev->bitmap_info.daemon_sleep;
 514         if (!daemon_sleep ||
 515             (daemon_sleep < 1) || (daemon_sleep > MAX_SCHEDULE_TIMEOUT)) {
 516                 printk(KERN_INFO "Choosing daemon_sleep default (5 sec)\n");
 517                 daemon_sleep = 5 * HZ;
 518         }
 519         sb->daemon_sleep = cpu_to_le32(daemon_sleep);
 520         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 521
 522         /*
 523          * FIXME: write_behind for RAID1.  If not specified, what
 524          * is a good choice?  We choose COUNTER_MAX / 2 arbitrarily.
 525          */
 526         write_behind = bitmap->mddev->bitmap_info.max_write_behind;
 527         if (write_behind > COUNTER_MAX)
 528                 write_behind = COUNTER_MAX / 2;
 529         sb->write_behind = cpu_to_le32(write_behind);
 530         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 531
 532         /* keep the array size field of the bitmap superblock up to date */
 533         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 534
 535         memcpy(sb->uuid, bitmap->mddev->uuid, 16);
 536
 537         bitmap->flags |= BITMAP_STALE;
 538         sb->state |= cpu_to_le32(BITMAP_STALE);
 539         bitmap->events_cleared = bitmap->mddev->events;
 540         sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
 541
 542         kunmap_atomic(sb);
 543
 544         return 0;
 545 }
 546
 547 /* read the superblock from the bitmap file and initialize some bitmap fields */
 548 static int bitmap_read_sb(struct bitmap *bitmap)
 549 {
 550         char *reason = NULL;
 551         bitmap_super_t *sb;
 552         unsigned long chunksize, daemon_sleep, write_behind;
 553         unsigned long long events;
 554         int err = -EINVAL;
 555
 556         /* page 0 is the superblock, read it... */
 557         if (bitmap->file) {
 558                 loff_t isize = i_size_read(bitmap->file->f_mapping->host);
 559                 int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
 560
 561                 bitmap->sb_page = read_page(bitmap->file, 0, bitmap, bytes);
 562         } else {
 563                 bitmap->sb_page = read_sb_page(bitmap->mddev,
 564                                                bitmap->mddev->bitmap_info.offset,
 565                                                NULL,
 566                                                0, sizeof(bitmap_super_t));
 567         }
 568         if (IS_ERR(bitmap->sb_page)) {
 569                 err = PTR_ERR(bitmap->sb_page);
 570                 bitmap->sb_page = NULL;
 571                 return err;
 572         }
 573
 574         sb = kmap_atomic(bitmap->sb_page);
 575
 576         chunksize = le32_to_cpu(sb->chunksize);
 577         daemon_sleep = le32_to_cpu(sb->daemon_sleep) * HZ;
 578         write_behind = le32_to_cpu(sb->write_behind);
 579
 580         /* verify that the bitmap-specific fields are valid */
 581         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
 582                 reason = "bad magic";
 583         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
 584                  le32_to_cpu(sb->version) > BITMAP_MAJOR_HI)
 585                 reason = "unrecognized superblock version";
 586         else if (chunksize < 512)
 587                 reason = "bitmap chunksize too small";
 588         else if (!is_power_of_2(chunksize))
 589                 reason = "bitmap chunksize not a power of 2";
 590         else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT)
 591                 reason = "daemon sleep period out of range";
 592         else if (write_behind > COUNTER_MAX)
 593                 reason = "write-behind limit out of range (0 - 16383)";
 594         if (reason) {
 595                 printk(KERN_INFO "%s: invalid bitmap file superblock: %s\n",
 596                         bmname(bitmap), reason);
 597                 goto out;
 598         }
 599
 600         /* keep the array size field of the bitmap superblock up to date */
 601         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 602
 603         if (bitmap->mddev->persistent) {
 604                 /*
 605                  * We have a persistent array superblock, so compare the
 606                  * bitmap's UUID and event counter to the mddev's
 607                  */
 608                 if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
 609                         printk(KERN_INFO
 610                                "%s: bitmap superblock UUID mismatch\n",
 611                                bmname(bitmap));
 612                         goto out;
 613                 }
 614                 events = le64_to_cpu(sb->events);
 615                 if (events < bitmap->mddev->events) {
 616                         printk(KERN_INFO
 617                                "%s: bitmap file is out of date (%llu < %llu) "
 618                                "-- forcing full recovery\n",
 619                                bmname(bitmap), events,
 620                                (unsigned long long) bitmap->mddev->events);
 621                         sb->state |= cpu_to_le32(BITMAP_STALE);
 622                 }
 623         }
 624
 625         /* assign fields using values from superblock */
 626         bitmap->mddev->bitmap_info.chunksize = chunksize;
 627         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 628         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 629         bitmap->flags |= le32_to_cpu(sb->state);
 630         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
 631                 bitmap->flags |= BITMAP_HOSTENDIAN;
 632         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
 633         if (bitmap->flags & BITMAP_STALE)
 634                 bitmap->events_cleared = bitmap->mddev->events;
 635         err = 0;
 636 out:
 637         kunmap_atomic(sb);
 638         if (err)
 639                 bitmap_print_sb(bitmap);
 640         return err;
 641 }
 642
 643 enum bitmap_mask_op {
 644         MASK_SET,
 645         MASK_UNSET
 646 };
 647
 648 /* record the state of the bitmap in the superblock.  Return the old value */
 649 static int bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
 650                              enum bitmap_mask_op op)
 651 {
 652         bitmap_super_t *sb;
 653         int old;
 654
 655         if (!bitmap->sb_page) /* can't set the state */
 656                 return 0;
 657         sb = kmap_atomic(bitmap->sb_page);
 658         old = le32_to_cpu(sb->state) & bits;
 659         switch (op) {
 660         case MASK_SET:
 661                 sb->state |= cpu_to_le32(bits);
 662                 bitmap->flags |= bits;
 663                 break;
 664         case MASK_UNSET:
 665                 sb->state &= cpu_to_le32(~bits);
 666                 bitmap->flags &= ~bits;
 667                 break;
 668         default:
 669                 BUG();
 670         }
 671         kunmap_atomic(sb);
 672         return old;
 673 }
 674
 675 /*
 676  * general bitmap file operations
 677  */
 678
 679 /*
 680  * on-disk bitmap:
 681  *
 682  * Use one bit per "chunk" (block set). We do the disk I/O on the bitmap
 683  * file a page at a time. There's a superblock at the start of the file.
 684  */
 685 /* calculate the index of the page that contains this bit */
 686 static inline unsigned long file_page_index(struct bitmap *bitmap, unsigned long chunk)
 687 {
 688         if (!bitmap->mddev->bitmap_info.external)
 689                 chunk += sizeof(bitmap_super_t) << 3;
 690         return chunk >> PAGE_BIT_SHIFT;
 691 }
 692
 693 /* calculate the (bit) offset of this bit within a page */
 694 static inline unsigned long file_page_offset(struct bitmap *bitmap, unsigned long chunk)
 695 {
 696         if (!bitmap->mddev->bitmap_info.external)
 697                 chunk += sizeof(bitmap_super_t) << 3;
 698         return chunk & (PAGE_BITS - 1);
 699 }
 700
 701 /*
 702  * return a pointer to the page in the filemap that contains the given bit
 703  *
 704  * this lookup is complicated by the fact that the bitmap sb might be exactly
 705  * 1 page (e.g., x86) or less than 1 page -- so the bitmap might start on page
 706  * 0 or page 1
 707  */
 708 static inline struct page *filemap_get_page(struct bitmap *bitmap,
 709                                             unsigned long chunk)
 710 {
 711         if (file_page_index(bitmap, chunk) >= bitmap->file_pages)
 712                 return NULL;
 713         return bitmap->filemap[file_page_index(bitmap, chunk)
 714                                - file_page_index(bitmap, 0)];
 715 }
 716
 717 static void bitmap_file_unmap(struct bitmap *bitmap)
 718 {
 719         struct page **map, *sb_page;
 720         unsigned long *attr;
 721         int pages;
 722         unsigned long flags;
 723
 724         spin_lock_irqsave(&bitmap->lock, flags);
 725         map = bitmap->filemap;
 726         bitmap->filemap = NULL;
 727         attr = bitmap->filemap_attr;
 728         bitmap->filemap_attr = NULL;
 729         pages = bitmap->file_pages;
 730         bitmap->file_pages = 0;
 731         sb_page = bitmap->sb_page;
 732         bitmap->sb_page = NULL;
 733         spin_unlock_irqrestore(&bitmap->lock, flags);
 734
 735         while (pages--)
 736                 if (map[pages] != sb_page) /* 0 is sb_page, release it below */
 737                         free_buffers(map[pages]);
 738         kfree(map);
 739         kfree(attr);
 740
 741         if (sb_page)
 742                 free_buffers(sb_page);
 743 }
 744
 745 static void bitmap_file_put(struct bitmap *bitmap)
 746 {
 747         struct file *file;
 748         unsigned long flags;
 749
 750         spin_lock_irqsave(&bitmap->lock, flags);
 751         file = bitmap->file;
 752         bitmap->file = NULL;
 753         spin_unlock_irqrestore(&bitmap->lock, flags);
 754
 755         if (file)
 756                 wait_event(bitmap->write_wait,
 757                            atomic_read(&bitmap->pending_writes)==0);
 758         bitmap_file_unmap(bitmap);
 759
 760         if (file) {
 761                 struct inode *inode = file->f_path.dentry->d_inode;
 762                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
 763                 fput(file);
 764         }
 765 }
 766
 767 /*
 768  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
 769  * then it is no longer reliable, so we stop using it and we mark the file
 770  * as failed in the superblock
 771  */
 772 static void bitmap_file_kick(struct bitmap *bitmap)
 773 {
 774         char *path, *ptr = NULL;
 775
 776         if (bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET) == 0) {
 777                 bitmap_update_sb(bitmap);
 778
 779                 if (bitmap->file) {
 780                         path = kmalloc(PAGE_SIZE, GFP_KERNEL);
 781                         if (path)
 782                                 ptr = d_path(&bitmap->file->f_path, path,
 783                                              PAGE_SIZE);
 784
 785                         printk(KERN_ALERT
 786                               "%s: kicking failed bitmap file %s from array!\n",
 787                               bmname(bitmap), IS_ERR(ptr) ? "" : ptr);
 788
 789                         kfree(path);
 790                 } else
 791                         printk(KERN_ALERT
 792                                "%s: disabling internal bitmap due to errors\n",
 793                                bmname(bitmap));
 794         }
 795
 796         bitmap_file_put(bitmap);
 797
 798         return;
 799 }
 800
 801 enum bitmap_page_attr {
 802         BITMAP_PAGE_DIRTY = 0,     /* there are set bits that need to be synced */
 803         BITMAP_PAGE_PENDING = 1,   /* there are bits that are being cleaned.
 804                                     * i.e. counter is 1 or 2. */
 805         BITMAP_PAGE_NEEDWRITE = 2, /* there are cleared bits that need to be synced */
 806 };
 807
 808 static inline void set_page_attr(struct bitmap *bitmap, struct page *page,
 809                                 enum bitmap_page_attr attr)
 810 {
 811         __set_bit((page->index<<2) + attr, bitmap->filemap_attr);
 812 }
 813
 814 static inline void clear_page_attr(struct bitmap *bitmap, struct page *page,
 815                                 enum bitmap_page_attr attr)
 816 {
 817         __clear_bit((page->index<<2) + attr, bitmap->filemap_attr);
 818 }
 819
 820 static inline unsigned long test_page_attr(struct bitmap *bitmap, struct page *page,
 821                                            enum bitmap_page_attr attr)
 822 {
 823         return test_bit((page->index<<2) + attr, bitmap->filemap_attr);
 824 }
 825
 826 /*
 827  * bitmap_file_set_bit -- called before performing a write to the md device
 828  * to set (and eventually sync) a particular bit in the bitmap file
 829  *
 830  * we set the bit immediately, then we record the page number so that
 831  * when an unplug occurs, we can flush the dirty pages out to disk
 832  */
 833 static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 834 {
 835         unsigned long bit;
 836         struct page *page;
 837         void *kaddr;
 838         unsigned long chunk = block >> bitmap->chunkshift;
 839
 840         if (!bitmap->filemap)
 841                 return;
 842
 843         page = filemap_get_page(bitmap, chunk);
 844         if (!page)
 845                 return;
 846         bit = file_page_offset(bitmap, chunk);
 847
 848         /* set the bit */
 849         kaddr = kmap_atomic(page);
 850         if (bitmap->flags & BITMAP_HOSTENDIAN)
 851                 set_bit(bit, kaddr);
 852         else
 853                 __set_bit_le(bit, kaddr);
 854         kunmap_atomic(kaddr);
 855         pr_debug("set file bit %lu page %lu\n", bit, page->index);
 856         /* record page number so it gets flushed to disk when unplug occurs */
 857         set_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 858 }
 859
 860 /* this gets called when the md device is ready to unplug its underlying
 861  * (slave) device queues -- before we let any writes go down, we need to
 862  * sync the dirty pages of the bitmap file to disk */
 863 void bitmap_unplug(struct bitmap *bitmap)
 864 {
 865         unsigned long i, flags;
 866         int dirty, need_write;
 867         struct page *page;
 868         int wait = 0;
 869
 870         if (!bitmap)
 871                 return;
 872
 873         /* look at each page to see if there are any set bits that need to be
 874          * flushed out to disk */
 875         for (i = 0; i < bitmap->file_pages; i++) {
 876                 spin_lock_irqsave(&bitmap->lock, flags);
 877                 if (!bitmap->filemap) {
 878                         spin_unlock_irqrestore(&bitmap->lock, flags);
 879                         return;
 880                 }
 881                 page = bitmap->filemap[i];
 882                 dirty = test_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 883                 need_write = test_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 884                 clear_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 885                 clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 886                 if (dirty)
 887                         wait = 1;
 888                 spin_unlock_irqrestore(&bitmap->lock, flags);
 889
 890                 if (dirty || need_write)
 891                         write_page(bitmap, page, 0);
 892         }
 893         if (wait) { /* if any writes were performed, we need to wait on them */
 894                 if (bitmap->file)
 895                         wait_event(bitmap->write_wait,
 896                                    atomic_read(&bitmap->pending_writes)==0);
 897                 else
 898                         md_super_wait(bitmap->mddev);
 899         }
 900         if (bitmap->flags & BITMAP_WRITE_ERROR)
 901                 bitmap_file_kick(bitmap);
 902 }
 903 EXPORT_SYMBOL(bitmap_unplug);
 904
 905 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
 906 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
 907  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
 908  * memory mapping of the bitmap file
 909  * Special cases:
 910  *   if there's no bitmap file, or if the bitmap file had been
 911  *   previously kicked from the array, we mark all the bits as
 912  *   1's in order to cause a full resync.
 913  *
 914  * We ignore all bits for sectors that end earlier than 'start'.
 915  * This is used when reading an out-of-date bitmap...
 916  */
 917 static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
 918 {
 919         unsigned long i, chunks, index, oldindex, bit;
 920         struct page *page = NULL, *oldpage = NULL;
 921         unsigned long num_pages, bit_cnt = 0;
 922         struct file *file;
 923         unsigned long bytes, offset;
 924         int outofdate;
 925         int ret = -ENOSPC;
 926         void *paddr;
 927
 928         chunks = bitmap->chunks;
 929         file = bitmap->file;
 930
 931         BUG_ON(!file && !bitmap->mddev->bitmap_info.offset);
 932
 933         outofdate = bitmap->flags & BITMAP_STALE;
 934         if (outofdate)
 935                 printk(KERN_INFO "%s: bitmap file is out of date, doing full "
 936                         "recovery\n", bmname(bitmap));
 937
 938         bytes = DIV_ROUND_UP(bitmap->chunks, 8);
 939         if (!bitmap->mddev->bitmap_info.external)
 940                 bytes += sizeof(bitmap_super_t);
 941
 942         num_pages = DIV_ROUND_UP(bytes, PAGE_SIZE);
 943
 944         if (file && i_size_read(file->f_mapping->host) < bytes) {
 945                 printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
 946                         bmname(bitmap),
 947                         (unsigned long) i_size_read(file->f_mapping->host),
 948                         bytes);
 949                 goto err;
 950         }
 951
 952         ret = -ENOMEM;
 953
 954         bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
 955         if (!bitmap->filemap)
 956                 goto err;
 957
 958         /* We need 4 bits per page, rounded up to a multiple of sizeof(unsigned long) */
 959         bitmap->filemap_attr = kzalloc(
 960                 roundup(DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
 961                 GFP_KERNEL);
 962         if (!bitmap->filemap_attr)
 963                 goto err;
 964
 965         oldindex = ~0L;
 966
 967         for (i = 0; i < chunks; i++) {
 968                 int b;
 969                 index = file_page_index(bitmap, i);
 970                 bit = file_page_offset(bitmap, i);
 971                 if (index != oldindex) { /* this is a new page, read it in */
 972                         int count;
 973                         /* unmap the old page, we're done with it */
 974                         if (index == num_pages-1)
 975                                 count = bytes - index * PAGE_SIZE;
 976                         else
 977                                 count = PAGE_SIZE;
 978                         if (index == 0 && bitmap->sb_page) {
 979                                 /*
 980                                  * if we're here then the superblock page
 981                                  * contains some bits (PAGE_SIZE != sizeof sb)
 982                                  * we've already read it in, so just use it
 983                                  */
 984                                 page = bitmap->sb_page;
 985                                 offset = sizeof(bitmap_super_t);
 986                                 if (!file)
 987                                         page = read_sb_page(
 988                                                 bitmap->mddev,
 989                                                 bitmap->mddev->bitmap_info.offset,
 990                                                 page,
 991                                                 index, count);
 992                         } else if (file) {
 993                                 page = read_page(file, index, bitmap, count);
 994                                 offset = 0;
 995                         } else {
 996                                 page = read_sb_page(bitmap->mddev,
 997                                                     bitmap->mddev->bitmap_info.offset,
 998                                                     NULL,
 999                                                     index, count);
1000                                 offset = 0;
1001                         }
1002                         if (IS_ERR(page)) { /* read error */
1003                                 ret = PTR_ERR(page);
1004                                 goto err;
1005                         }
1006
1007                         oldindex = index;
1008                         oldpage = page;
1009
1010                         bitmap->filemap[bitmap->file_pages++] = page;
1011                         bitmap->last_page_size = count;
1012
1013                         if (outofdate) {
1014                                 /*
1015                                  * if bitmap is out of date, dirty the
1016                                  * whole page and write it out
1017                                  */
1018                                 paddr = kmap_atomic(page);
1019                                 memset(paddr + offset, 0xff,
1020                                        PAGE_SIZE - offset);
1021                                 kunmap_atomic(paddr);
1022                                 write_page(bitmap, page, 1);
1023
1024                                 ret = -EIO;
1025                                 if (bitmap->flags & BITMAP_WRITE_ERROR)
1026                                         goto err;
1027                         }
1028                 }
1029                 paddr = kmap_atomic(page);
1030                 if (bitmap->flags & BITMAP_HOSTENDIAN)
1031                         b = test_bit(bit, paddr);
1032                 else
1033                         b = test_bit_le(bit, paddr);
1034                 kunmap_atomic(paddr);
1035                 if (b) {
1036                         /* if the disk bit is set, set the memory bit */
1037                         int needed = ((sector_t)(i+1) << bitmap->chunkshift
1038                                       >= start);
1039                         bitmap_set_memory_bits(bitmap,
1040                                                (sector_t)i << bitmap->chunkshift,
1041                                                needed);
1042                         bit_cnt++;
1043                 }
1044         }
1045
1046         /* everything went OK */
1047         ret = 0;
1048         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_UNSET);
1049
1050         if (bit_cnt) { /* Kick recovery if any bits were set */
1051                 set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
1052                 md_wakeup_thread(bitmap->mddev->thread);
1053         }
1054
1055         printk(KERN_INFO "%s: bitmap initialized from disk: "
1056                "read %lu/%lu pages, set %lu of %lu bits\n",
1057                bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt, chunks);
1058
1059         return 0;
1060
1061  err:
1062         printk(KERN_INFO "%s: bitmap initialisation failed: %d\n",
1063                bmname(bitmap), ret);
1064         return ret;
1065 }
1066
1067 void bitmap_write_all(struct bitmap *bitmap)
1068 {
1069         /* We don't actually write all bitmap blocks here,
1070          * just flag them as needing to be written
1071          */
1072         int i;
1073
1074         spin_lock_irq(&bitmap->lock);
1075         for (i = 0; i < bitmap->file_pages; i++)
1076                 set_page_attr(bitmap, bitmap->filemap[i],
1077                               BITMAP_PAGE_NEEDWRITE);
1078         bitmap->allclean = 0;
1079         spin_unlock_irq(&bitmap->lock);
1080 }
1081
1082 static void bitmap_count_page(struct bitmap *bitmap, sector_t offset, int inc)
1083 {
1084         sector_t chunk = offset >> bitmap->chunkshift;
1085         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1086         bitmap->bp[page].count += inc;
1087         bitmap_checkfree(bitmap, page);
1088 }
1089 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1090                                             sector_t offset, sector_t *blocks,
1091                                             int create);
1092
1093 /*
1094  * bitmap daemon -- periodically wakes up to clean bits and flush pages
1095  *                      out to disk
1096  */
1097
1098 void bitmap_daemon_work(struct mddev *mddev)
1099 {
1100         struct bitmap *bitmap;
1101         unsigned long j;
1102         unsigned long flags;
1103         struct page *page = NULL, *lastpage = NULL;
1104         sector_t blocks;
1105         void *paddr;
1106
1107         /* Use a mutex to guard daemon_work against
1108          * bitmap_destroy.
1109          */
1110         mutex_lock(&mddev->bitmap_info.mutex);
1111         bitmap = mddev->bitmap;
1112         if (bitmap == NULL) {
1113                 mutex_unlock(&mddev->bitmap_info.mutex);
1114                 return;
1115         }
1116         if (time_before(jiffies, bitmap->daemon_lastrun
1117                         + mddev->bitmap_info.daemon_sleep))
1118                 goto done;
1119
1120         bitmap->daemon_lastrun = jiffies;
1121         if (bitmap->allclean) {
1122                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1123                 goto done;
1124         }
1125         bitmap->allclean = 1;
1126
1127         spin_lock_irqsave(&bitmap->lock, flags);
1128         for (j = 0; j < bitmap->chunks; j++) {
1129                 bitmap_counter_t *bmc;
1130                 if (!bitmap->filemap)
1131                         /* error or shutdown */
1132                         break;
1133
1134                 page = filemap_get_page(bitmap, j);
1135
1136                 if (page != lastpage) {
1137                         /* skip this page unless it's marked as needing cleaning */
1138                         if (!test_page_attr(bitmap, page, BITMAP_PAGE_PENDING)) {
1139                                 int need_write = test_page_attr(bitmap, page,
1140                                                                 BITMAP_PAGE_NEEDWRITE);
1141                                 if (need_write)
1142                                         clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
1143
1144                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1145                                 if (need_write)
1146                                         write_page(bitmap, page, 0);
1147                                 spin_lock_irqsave(&bitmap->lock, flags);
1148                                 j |= (PAGE_BITS - 1);
1149                                 continue;
1150                         }
1151
1152                         /* grab the new page, sync and release the old */
1153                         if (lastpage != NULL) {
1154                                 if (test_page_attr(bitmap, lastpage,
1155                                                    BITMAP_PAGE_NEEDWRITE)) {
1156                                         clear_page_attr(bitmap, lastpage,
1157                                                         BITMAP_PAGE_NEEDWRITE);
1158                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1159                                         write_page(bitmap, lastpage, 0);
1160                                 } else {
1161                                         set_page_attr(bitmap, lastpage,
1162                                                       BITMAP_PAGE_NEEDWRITE);
1163                                         bitmap->allclean = 0;
1164                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1165                                 }
1166                         } else
1167                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1168                         lastpage = page;
1169
1170                         /* We are possibly going to clear some bits, so make
1171                          * sure that events_cleared is up-to-date.
1172                          */
1173                         if (bitmap->need_sync &&
1174                             mddev->bitmap_info.external == 0) {
1175                                 bitmap_super_t *sb;
1176                                 bitmap->need_sync = 0;
1177                                 sb = kmap_atomic(bitmap->sb_page);
1178                                 sb->events_cleared =
1179                                         cpu_to_le64(bitmap->events_cleared);
1180                                 kunmap_atomic(sb);
1181                                 write_page(bitmap, bitmap->sb_page, 1);
1182                         }
1183                         spin_lock_irqsave(&bitmap->lock, flags);
1184                         if (!bitmap->need_sync)
1185                                 clear_page_attr(bitmap, page, BITMAP_PAGE_PENDING);
1186                         else
1187                                 bitmap->allclean = 0;
1188                 }
1189                 bmc = bitmap_get_counter(bitmap,
1190                                          (sector_t)j << bitmap->chunkshift,
1191                                          &blocks, 0);
1192                 if (!bmc)
1193                         j |= PAGE_COUNTER_MASK;
1194                 else if (*bmc) {
1195                         if (*bmc == 1 && !bitmap->need_sync) {
1196                                 /* we can clear the bit */
1197                                 *bmc = 0;
1198                                 bitmap_count_page(bitmap,
1199                                                   (sector_t)j << bitmap->chunkshift,
1200                                                   -1);
1201
1202                                 /* clear the bit */
1203                                 paddr = kmap_atomic(page);
1204                                 if (bitmap->flags & BITMAP_HOSTENDIAN)
1205                                         clear_bit(file_page_offset(bitmap, j),
1206                                                   paddr);
1207                                 else
1208                                         __clear_bit_le(
1209                                                 file_page_offset(bitmap,
1210                                                                  j),
1211                                                 paddr);
1212                                 kunmap_atomic(paddr);
1213                         } else if (*bmc <= 2) {
1214                                 *bmc = 1; /* maybe clear the bit next time */
1215                                 set_page_attr(bitmap, page, BITMAP_PAGE_PENDING);
1216                                 bitmap->allclean = 0;
1217                         }
1218                 }
1219         }
1220         spin_unlock_irqrestore(&bitmap->lock, flags);
1221
1222         /* now sync the final page */
1223         if (lastpage != NULL) {
1224                 spin_lock_irqsave(&bitmap->lock, flags);
1225                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1226                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1227                         spin_unlock_irqrestore(&bitmap->lock, flags);
1228                         write_page(bitmap, lastpage, 0);
1229                 } else {
1230                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1231                         bitmap->allclean = 0;
1232                         spin_unlock_irqrestore(&bitmap->lock, flags);
1233                 }
1234         }
1235
1236  done:
1237         if (bitmap->allclean == 0)
1238                 mddev->thread->timeout =
1239                         mddev->bitmap_info.daemon_sleep;
1240         mutex_unlock(&mddev->bitmap_info.mutex);
1241 }
1242
1243 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1244                                             sector_t offset, sector_t *blocks,
1245                                             int create)
1246 __releases(bitmap->lock)
1247 __acquires(bitmap->lock)
1248 {
1249         /* If 'create', we might release the lock and reclaim it.
1250          * The lock must have been taken with interrupts enabled.
1251          * If !create, we don't release the lock.
1252          */
1253         sector_t chunk = offset >> bitmap->chunkshift;
1254         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1255         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1256         sector_t csize;
1257         int err;
1258
1259         err = bitmap_checkpage(bitmap, page, create);
1260
1261         if (bitmap->bp[page].hijacked ||
1262             bitmap->bp[page].map == NULL)
1263                 csize = ((sector_t)1) << (bitmap->chunkshift +
1264                                           PAGE_COUNTER_SHIFT - 1);
1265         else
1266                 csize = ((sector_t)1) << bitmap->chunkshift;
1267         *blocks = csize - (offset & (csize - 1));
1268
1269         if (err < 0)
1270                 return NULL;
1271
1272         /* now locked ... */
1273
1274         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1275                 /* should we use the first or second counter field
1276                  * of the hijacked pointer? */
1277                 int hi = (pageoff > PAGE_COUNTER_MASK);
1278                 return  &((bitmap_counter_t *)
1279                           &bitmap->bp[page].map)[hi];
1280         } else /* page is allocated */
1281                 return (bitmap_counter_t *)
1282                         &(bitmap->bp[page].map[pageoff]);
1283 }
1284
1285 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1286 {
1287         if (!bitmap)
1288                 return 0;
1289
1290         if (behind) {
1291                 int bw;
1292                 atomic_inc(&bitmap->behind_writes);
1293                 bw = atomic_read(&bitmap->behind_writes);
1294                 if (bw > bitmap->behind_writes_used)
1295                         bitmap->behind_writes_used = bw;
1296
1297                 pr_debug("inc write-behind count %d/%lu\n",
1298                          bw, bitmap->mddev->bitmap_info.max_write_behind);
1299         }
1300
1301         while (sectors) {
1302                 sector_t blocks;
1303                 bitmap_counter_t *bmc;
1304
1305                 spin_lock_irq(&bitmap->lock);
1306                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 1);
1307                 if (!bmc) {
1308                         spin_unlock_irq(&bitmap->lock);
1309                         return 0;
1310                 }
1311
1312                 if (unlikely(COUNTER(*bmc) == COUNTER_MAX)) {
1313                         DEFINE_WAIT(__wait);
1314                         /* note that it is safe to do the prepare_to_wait
1315                          * after the test as long as we do it before dropping
1316                          * the spinlock.
1317                          */
1318                         prepare_to_wait(&bitmap->overflow_wait, &__wait,
1319                                         TASK_UNINTERRUPTIBLE);
1320                         spin_unlock_irq(&bitmap->lock);
1321                         io_schedule();
1322                         finish_wait(&bitmap->overflow_wait, &__wait);
1323                         continue;
1324                 }
1325
1326                 switch (*bmc) {
1327                 case 0:
1328                         bitmap_file_set_bit(bitmap, offset);
1329                         bitmap_count_page(bitmap, offset, 1);
1330                         /* fall through */
1331                 case 1:
1332                         *bmc = 2;
1333                 }
1334
1335                 (*bmc)++;
1336
1337                 spin_unlock_irq(&bitmap->lock);
1338
1339                 offset += blocks;
1340                 if (sectors > blocks)
1341                         sectors -= blocks;
1342                 else
1343                         sectors = 0;
1344         }
1345         return 0;
1346 }
1347 EXPORT_SYMBOL(bitmap_startwrite);
1348
1349 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1350                      int success, int behind)
1351 {
1352         if (!bitmap)
1353                 return;
1354         if (behind) {
1355                 if (atomic_dec_and_test(&bitmap->behind_writes))
1356                         wake_up(&bitmap->behind_wait);
1357                 pr_debug("dec write-behind count %d/%lu\n",
1358                          atomic_read(&bitmap->behind_writes),
1359                          bitmap->mddev->bitmap_info.max_write_behind);
1360         }
1361
1362         while (sectors) {
1363                 sector_t blocks;
1364                 unsigned long flags;
1365                 bitmap_counter_t *bmc;
1366
1367                 spin_lock_irqsave(&bitmap->lock, flags);
1368                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 0);
1369                 if (!bmc) {
1370                         spin_unlock_irqrestore(&bitmap->lock, flags);
1371                         return;
1372                 }
1373
1374                 if (success && !bitmap->mddev->degraded &&
1375                     bitmap->events_cleared < bitmap->mddev->events) {
1376                         bitmap->events_cleared = bitmap->mddev->events;
1377                         bitmap->need_sync = 1;
1378                         sysfs_notify_dirent_safe(bitmap->sysfs_can_clear);
1379                 }
1380
1381                 if (!success && !NEEDED(*bmc))
1382                         *bmc |= NEEDED_MASK;
1383
1384                 if (COUNTER(*bmc) == COUNTER_MAX)
1385                         wake_up(&bitmap->overflow_wait);
1386
1387                 (*bmc)--;
1388                 if (*bmc <= 2) {
1389                         set_page_attr(bitmap,
1390                                       filemap_get_page(
1391                                               bitmap,
1392                                               offset >> bitmap->chunkshift),
1393                                       BITMAP_PAGE_PENDING);
1394                         bitmap->allclean = 0;
1395                 }
1396                 spin_unlock_irqrestore(&bitmap->lock, flags);
1397                 offset += blocks;
1398                 if (sectors > blocks)
1399                         sectors -= blocks;
1400                 else
1401                         sectors = 0;
1402         }
1403 }
1404 EXPORT_SYMBOL(bitmap_endwrite);
1405
1406 static int __bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1407                                int degraded)
1408 {
1409         bitmap_counter_t *bmc;
1410         int rv;
1411         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1412                 *blocks = 1024;
1413                 return 1; /* always resync if no bitmap */
1414         }
1415         spin_lock_irq(&bitmap->lock);
1416         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1417         rv = 0;
1418         if (bmc) {
1419                 /* locked */
1420                 if (RESYNC(*bmc))
1421                         rv = 1;
1422                 else if (NEEDED(*bmc)) {
1423                         rv = 1;
1424                         if (!degraded) { /* don't set/clear bits if degraded */
1425                                 *bmc |= RESYNC_MASK;
1426                                 *bmc &= ~NEEDED_MASK;
1427                         }
1428                 }
1429         }
1430         spin_unlock_irq(&bitmap->lock);
1431         return rv;
1432 }
1433
1434 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1435                       int degraded)
1436 {
1437         /* bitmap_start_sync must always report on multiples of whole
1438          * pages, otherwise resync (which is very PAGE_SIZE based) will
1439          * get confused.
1440          * So call __bitmap_start_sync repeatedly (if needed) until
1441          * At least PAGE_SIZE>>9 blocks are covered.
1442          * Return the 'or' of the result.
1443          */
1444         int rv = 0;
1445         sector_t blocks1;
1446
1447         *blocks = 0;
1448         while (*blocks < (PAGE_SIZE>>9)) {
1449                 rv |= __bitmap_start_sync(bitmap, offset,
1450                                           &blocks1, degraded);
1451                 offset += blocks1;
1452                 *blocks += blocks1;
1453         }
1454         return rv;
1455 }
1456 EXPORT_SYMBOL(bitmap_start_sync);
1457
1458 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks, int aborted)
1459 {
1460         bitmap_counter_t *bmc;
1461         unsigned long flags;
1462
1463         if (bitmap == NULL) {
1464                 *blocks = 1024;
1465                 return;
1466         }
1467         spin_lock_irqsave(&bitmap->lock, flags);
1468         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1469         if (bmc == NULL)
1470                 goto unlock;
1471         /* locked */
1472         if (RESYNC(*bmc)) {
1473                 *bmc &= ~RESYNC_MASK;
1474
1475                 if (!NEEDED(*bmc) && aborted)
1476                         *bmc |= NEEDED_MASK;
1477                 else {
1478                         if (*bmc <= 2) {
1479                                 set_page_attr(bitmap,
1480                                               filemap_get_page(bitmap, offset >> bitmap->chunkshift),
1481                                               BITMAP_PAGE_PENDING);
1482                                 bitmap->allclean = 0;
1483                         }
1484                 }
1485         }
1486  unlock:
1487         spin_unlock_irqrestore(&bitmap->lock, flags);
1488 }
1489 EXPORT_SYMBOL(bitmap_end_sync);
1490
1491 void bitmap_close_sync(struct bitmap *bitmap)
1492 {
1493         /* Sync has finished, and any bitmap chunks that weren't synced
1494          * properly have been aborted.  It remains to us to clear the
1495          * RESYNC bit wherever it is still on
1496          */
1497         sector_t sector = 0;
1498         sector_t blocks;
1499         if (!bitmap)
1500                 return;
1501         while (sector < bitmap->mddev->resync_max_sectors) {
1502                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1503                 sector += blocks;
1504         }
1505 }
1506 EXPORT_SYMBOL(bitmap_close_sync);
1507
1508 void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector)
1509 {
1510         sector_t s = 0;
1511         sector_t blocks;
1512
1513         if (!bitmap)
1514                 return;
1515         if (sector == 0) {
1516                 bitmap->last_end_sync = jiffies;
1517                 return;
1518         }
1519         if (time_before(jiffies, (bitmap->last_end_sync
1520                                   + bitmap->mddev->bitmap_info.daemon_sleep)))
1521                 return;
1522         wait_event(bitmap->mddev->recovery_wait,
1523                    atomic_read(&bitmap->mddev->recovery_active) == 0);
1524
1525         bitmap->mddev->curr_resync_completed = sector;
1526         set_bit(MD_CHANGE_CLEAN, &bitmap->mddev->flags);
1527         sector &= ~((1ULL << bitmap->chunkshift) - 1);
1528         s = 0;
1529         while (s < sector && s < bitmap->mddev->resync_max_sectors) {
1530                 bitmap_end_sync(bitmap, s, &blocks, 0);
1531                 s += blocks;
1532         }
1533         bitmap->last_end_sync = jiffies;
1534         sysfs_notify(&bitmap->mddev->kobj, NULL, "sync_completed");
1535 }
1536 EXPORT_SYMBOL(bitmap_cond_end_sync);
1537
1538 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1539 {
1540         /* For each chunk covered by any of these sectors, set the
1541          * counter to 1 and set resync_needed.  They should all
1542          * be 0 at this point
1543          */
1544
1545         sector_t secs;
1546         bitmap_counter_t *bmc;
1547         spin_lock_irq(&bitmap->lock);
1548         bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
1549         if (!bmc) {
1550                 spin_unlock_irq(&bitmap->lock);
1551                 return;
1552         }
1553         if (!*bmc) {
1554                 struct page *page;
1555                 *bmc = 2 | (needed ? NEEDED_MASK : 0);
1556                 bitmap_count_page(bitmap, offset, 1);
1557                 page = filemap_get_page(bitmap, offset >> bitmap->chunkshift);
1558                 set_page_attr(bitmap, page, BITMAP_PAGE_PENDING);
1559                 bitmap->allclean = 0;
1560         }
1561         spin_unlock_irq(&bitmap->lock);
1562 }
1563
1564 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
1565 void bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1566 {
1567         unsigned long chunk;
1568
1569         for (chunk = s; chunk <= e; chunk++) {
1570                 sector_t sec = (sector_t)chunk << bitmap->chunkshift;
1571                 bitmap_set_memory_bits(bitmap, sec, 1);
1572                 spin_lock_irq(&bitmap->lock);
1573                 bitmap_file_set_bit(bitmap, sec);
1574                 spin_unlock_irq(&bitmap->lock);
1575                 if (sec < bitmap->mddev->recovery_cp)
1576                         /* We are asserting that the array is dirty,
1577                          * so move the recovery_cp address back so
1578                          * that it is obvious that it is dirty
1579                          */
1580                         bitmap->mddev->recovery_cp = sec;
1581         }
1582 }
1583
1584 /*
1585  * flush out any pending updates
1586  */
1587 void bitmap_flush(struct mddev *mddev)
1588 {
1589         struct bitmap *bitmap = mddev->bitmap;
1590         long sleep;
1591
1592         if (!bitmap) /* there was no bitmap */
1593                 return;
1594
1595         /* run the daemon_work three time to ensure everything is flushed
1596          * that can be
1597          */
1598         sleep = mddev->bitmap_info.daemon_sleep * 2;
1599         bitmap->daemon_lastrun -= sleep;
1600         bitmap_daemon_work(mddev);
1601         bitmap->daemon_lastrun -= sleep;
1602         bitmap_daemon_work(mddev);
1603         bitmap->daemon_lastrun -= sleep;
1604         bitmap_daemon_work(mddev);
1605         bitmap_update_sb(bitmap);
1606 }
1607
1608 /*
1609  * free memory that was allocated
1610  */
1611 static void bitmap_free(struct bitmap *bitmap)
1612 {
1613         unsigned long k, pages;
1614         struct bitmap_page *bp;
1615
1616         if (!bitmap) /* there was no bitmap */
1617                 return;
1618
1619         /* release the bitmap file and kill the daemon */
1620         bitmap_file_put(bitmap);
1621
1622         bp = bitmap->bp;
1623         pages = bitmap->pages;
1624
1625         /* free all allocated memory */
1626
1627         if (bp) /* deallocate the page memory */
1628                 for (k = 0; k < pages; k++)
1629                         if (bp[k].map && !bp[k].hijacked)
1630                                 kfree(bp[k].map);
1631         kfree(bp);
1632         kfree(bitmap);
1633 }
1634
1635 void bitmap_destroy(struct mddev *mddev)
1636 {
1637         struct bitmap *bitmap = mddev->bitmap;
1638
1639         if (!bitmap) /* there was no bitmap */
1640                 return;
1641
1642         mutex_lock(&mddev->bitmap_info.mutex);
1643         mddev->bitmap = NULL; /* disconnect from the md device */
1644         mutex_unlock(&mddev->bitmap_info.mutex);
1645         if (mddev->thread)
1646                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1647
1648         if (bitmap->sysfs_can_clear)
1649                 sysfs_put(bitmap->sysfs_can_clear);
1650
1651         bitmap_free(bitmap);
1652 }
1653
1654 /*
1655  * initialize the bitmap structure
1656  * if this returns an error, bitmap_destroy must be called to do clean up
1657  */
1658 int bitmap_create(struct mddev *mddev)
1659 {
1660         struct bitmap *bitmap;
1661         sector_t blocks = mddev->resync_max_sectors;
1662         unsigned long chunks;
1663         unsigned long pages;
1664         struct file *file = mddev->bitmap_info.file;
1665         int err;
1666         struct sysfs_dirent *bm = NULL;
1667
1668         BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
1669
1670         if (!file
1671             && !mddev->bitmap_info.offset) /* bitmap disabled, nothing to do */
1672                 return 0;
1673
1674         BUG_ON(file && mddev->bitmap_info.offset);
1675
1676         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1677         if (!bitmap)
1678                 return -ENOMEM;
1679
1680         spin_lock_init(&bitmap->lock);
1681         atomic_set(&bitmap->pending_writes, 0);
1682         init_waitqueue_head(&bitmap->write_wait);
1683         init_waitqueue_head(&bitmap->overflow_wait);
1684         init_waitqueue_head(&bitmap->behind_wait);
1685
1686         bitmap->mddev = mddev;
1687
1688         if (mddev->kobj.sd)
1689                 bm = sysfs_get_dirent(mddev->kobj.sd, NULL, "bitmap");
1690         if (bm) {
1691                 bitmap->sysfs_can_clear = sysfs_get_dirent(bm, NULL, "can_clear");
1692                 sysfs_put(bm);
1693         } else
1694                 bitmap->sysfs_can_clear = NULL;
1695
1696         bitmap->file = file;
1697         if (file) {
1698                 get_file(file);
1699                 /* As future accesses to this file will use bmap,
1700                  * and bypass the page cache, we must sync the file
1701                  * first.
1702                  */
1703                 vfs_fsync(file, 1);
1704         }
1705         /* read superblock from bitmap file (this sets mddev->bitmap_info.chunksize) */
1706         if (!mddev->bitmap_info.external) {
1707                 /*
1708                  * If 'MD_ARRAY_FIRST_USE' is set, then device-mapper is
1709                  * instructing us to create a new on-disk bitmap instance.
1710                  */
1711                 if (test_and_clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags))
1712                         err = bitmap_new_disk_sb(bitmap);
1713                 else
1714                         err = bitmap_read_sb(bitmap);
1715         } else {
1716                 err = 0;
1717                 if (mddev->bitmap_info.chunksize == 0 ||
1718                     mddev->bitmap_info.daemon_sleep == 0)
1719                         /* chunksize and time_base need to be
1720                          * set first. */
1721                         err = -EINVAL;
1722         }
1723         if (err)
1724                 goto error;
1725
1726         bitmap->daemon_lastrun = jiffies;
1727         bitmap->chunkshift = (ffz(~mddev->bitmap_info.chunksize)
1728                               - BITMAP_BLOCK_SHIFT);
1729
1730         /* now that chunksize and chunkshift are set, we can use these macros */
1731         chunks = (blocks + bitmap->chunkshift - 1) >>
1732                         bitmap->chunkshift;
1733         pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
1734
1735         BUG_ON(!pages);
1736
1737         bitmap->chunks = chunks;
1738         bitmap->pages = pages;
1739         bitmap->missing_pages = pages;
1740
1741         bitmap->bp = kzalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
1742
1743         err = -ENOMEM;
1744         if (!bitmap->bp)
1745                 goto error;
1746
1747         printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
1748                 pages, bmname(bitmap));
1749
1750         mddev->bitmap = bitmap;
1751
1752
1753         return (bitmap->flags & BITMAP_WRITE_ERROR) ? -EIO : 0;
1754
1755  error:
1756         bitmap_free(bitmap);
1757         return err;
1758 }
1759
1760 int bitmap_load(struct mddev *mddev)
1761 {
1762         int err = 0;
1763         sector_t start = 0;
1764         sector_t sector = 0;
1765         struct bitmap *bitmap = mddev->bitmap;
1766
1767         if (!bitmap)
1768                 goto out;
1769
1770         /* Clear out old bitmap info first:  Either there is none, or we
1771          * are resuming after someone else has possibly changed things,
1772          * so we should forget old cached info.
1773          * All chunks should be clean, but some might need_sync.
1774          */
1775         while (sector < mddev->resync_max_sectors) {
1776                 sector_t blocks;
1777                 bitmap_start_sync(bitmap, sector, &blocks, 0);
1778                 sector += blocks;
1779         }
1780         bitmap_close_sync(bitmap);
1781
1782         if (mddev->degraded == 0
1783             || bitmap->events_cleared == mddev->events)
1784                 /* no need to keep dirty bits to optimise a
1785                  * re-add of a missing device */
1786                 start = mddev->recovery_cp;
1787
1788         err = bitmap_init_from_disk(bitmap, start);
1789
1790         if (err)
1791                 goto out;
1792
1793         mddev->thread->timeout = mddev->bitmap_info.daemon_sleep;
1794         md_wakeup_thread(mddev->thread);
1795
1796         bitmap_update_sb(bitmap);
1797
1798         if (bitmap->flags & BITMAP_WRITE_ERROR)
1799                 err = -EIO;
1800 out:
1801         return err;
1802 }
1803 EXPORT_SYMBOL_GPL(bitmap_load);
1804
1805 void bitmap_status(struct seq_file *seq, struct bitmap *bitmap)
1806 {
1807         unsigned long chunk_kb;
1808         unsigned long flags;
1809
1810         if (!bitmap)
1811                 return;
1812
1813         spin_lock_irqsave(&bitmap->lock, flags);
1814         chunk_kb = bitmap->mddev->bitmap_info.chunksize >> 10;
1815         seq_printf(seq, "bitmap: %lu/%lu pages [%luKB], "
1816                    "%lu%s chunk",
1817                    bitmap->pages - bitmap->missing_pages,
1818                    bitmap->pages,
1819                    (bitmap->pages - bitmap->missing_pages)
1820                    << (PAGE_SHIFT - 10),
1821                    chunk_kb ? chunk_kb : bitmap->mddev->bitmap_info.chunksize,
1822                    chunk_kb ? "KB" : "B");
1823         if (bitmap->file) {
1824                 seq_printf(seq, ", file: ");
1825                 seq_path(seq, &bitmap->file->f_path, " \t\n");
1826         }
1827
1828         seq_printf(seq, "\n");
1829         spin_unlock_irqrestore(&bitmap->lock, flags);
1830 }
1831
1832 static ssize_t
1833 location_show(struct mddev *mddev, char *page)
1834 {
1835         ssize_t len;
1836         if (mddev->bitmap_info.file)
1837                 len = sprintf(page, "file");
1838         else if (mddev->bitmap_info.offset)
1839                 len = sprintf(page, "%+lld", (long long)mddev->bitmap_info.offset);
1840         else
1841                 len = sprintf(page, "none");
1842         len += sprintf(page+len, "\n");
1843         return len;
1844 }
1845
1846 static ssize_t
1847 location_store(struct mddev *mddev, const char *buf, size_t len)
1848 {
1849
1850         if (mddev->pers) {
1851                 if (!mddev->pers->quiesce)
1852                         return -EBUSY;
1853                 if (mddev->recovery || mddev->sync_thread)
1854                         return -EBUSY;
1855         }
1856
1857         if (mddev->bitmap || mddev->bitmap_info.file ||
1858             mddev->bitmap_info.offset) {
1859                 /* bitmap already configured.  Only option is to clear it */
1860                 if (strncmp(buf, "none", 4) != 0)
1861                         return -EBUSY;
1862                 if (mddev->pers) {
1863                         mddev->pers->quiesce(mddev, 1);
1864                         bitmap_destroy(mddev);
1865                         mddev->pers->quiesce(mddev, 0);
1866                 }
1867                 mddev->bitmap_info.offset = 0;
1868                 if (mddev->bitmap_info.file) {
1869                         struct file *f = mddev->bitmap_info.file;
1870                         mddev->bitmap_info.file = NULL;
1871                         restore_bitmap_write_access(f);
1872                         fput(f);
1873                 }
1874         } else {
1875                 /* No bitmap, OK to set a location */
1876                 long long offset;
1877                 if (strncmp(buf, "none", 4) == 0)
1878                         /* nothing to be done */;
1879                 else if (strncmp(buf, "file:", 5) == 0) {
1880                         /* Not supported yet */
1881                         return -EINVAL;
1882                 } else {
1883                         int rv;
1884                         if (buf[0] == '+')
1885                                 rv = strict_strtoll(buf+1, 10, &offset);
1886                         else
1887                                 rv = strict_strtoll(buf, 10, &offset);
1888                         if (rv)
1889                                 return rv;
1890                         if (offset == 0)
1891                                 return -EINVAL;
1892                         if (mddev->bitmap_info.external == 0 &&
1893                             mddev->major_version == 0 &&
1894                             offset != mddev->bitmap_info.default_offset)
1895                                 return -EINVAL;
1896                         mddev->bitmap_info.offset = offset;
1897                         if (mddev->pers) {
1898                                 mddev->pers->quiesce(mddev, 1);
1899                                 rv = bitmap_create(mddev);
1900                                 if (!rv)
1901                                         rv = bitmap_load(mddev);
1902                                 if (rv) {
1903                                         bitmap_destroy(mddev);
1904                                         mddev->bitmap_info.offset = 0;
1905                                 }
1906                                 mddev->pers->quiesce(mddev, 0);
1907                                 if (rv)
1908                                         return rv;
1909                         }
1910                 }
1911         }
1912         if (!mddev->external) {
1913                 /* Ensure new bitmap info is stored in
1914                  * metadata promptly.
1915                  */
1916                 set_bit(MD_CHANGE_DEVS, &mddev->flags);
1917                 md_wakeup_thread(mddev->thread);
1918         }
1919         return len;
1920 }
1921
1922 static struct md_sysfs_entry bitmap_location =
1923 __ATTR(location, S_IRUGO|S_IWUSR, location_show, location_store);
1924
1925 static ssize_t
1926 timeout_show(struct mddev *mddev, char *page)
1927 {
1928         ssize_t len;
1929         unsigned long secs = mddev->bitmap_info.daemon_sleep / HZ;
1930         unsigned long jifs = mddev->bitmap_info.daemon_sleep % HZ;
1931
1932         len = sprintf(page, "%lu", secs);
1933         if (jifs)
1934                 len += sprintf(page+len, ".%03u", jiffies_to_msecs(jifs));
1935         len += sprintf(page+len, "\n");
1936         return len;
1937 }
1938
1939 static ssize_t
1940 timeout_store(struct mddev *mddev, const char *buf, size_t len)
1941 {
1942         /* timeout can be set at any time */
1943         unsigned long timeout;
1944         int rv = strict_strtoul_scaled(buf, &timeout, 4);
1945         if (rv)
1946                 return rv;
1947
1948         /* just to make sure we don't overflow... */
1949         if (timeout >= LONG_MAX / HZ)
1950                 return -EINVAL;
1951
1952         timeout = timeout * HZ / 10000;
1953
1954         if (timeout >= MAX_SCHEDULE_TIMEOUT)
1955                 timeout = MAX_SCHEDULE_TIMEOUT-1;
1956         if (timeout < 1)
1957                 timeout = 1;
1958         mddev->bitmap_info.daemon_sleep = timeout;
1959         if (mddev->thread) {
1960                 /* if thread->timeout is MAX_SCHEDULE_TIMEOUT, then
1961                  * the bitmap is all clean and we don't need to
1962                  * adjust the timeout right now
1963                  */
1964                 if (mddev->thread->timeout < MAX_SCHEDULE_TIMEOUT) {
1965                         mddev->thread->timeout = timeout;
1966                         md_wakeup_thread(mddev->thread);
1967                 }
1968         }
1969         return len;
1970 }
1971
1972 static struct md_sysfs_entry bitmap_timeout =
1973 __ATTR(time_base, S_IRUGO|S_IWUSR, timeout_show, timeout_store);
1974
1975 static ssize_t
1976 backlog_show(struct mddev *mddev, char *page)
1977 {
1978         return sprintf(page, "%lu\n", mddev->bitmap_info.max_write_behind);
1979 }
1980
1981 static ssize_t
1982 backlog_store(struct mddev *mddev, const char *buf, size_t len)
1983 {
1984         unsigned long backlog;
1985         int rv = strict_strtoul(buf, 10, &backlog);
1986         if (rv)
1987                 return rv;
1988         if (backlog > COUNTER_MAX)
1989                 return -EINVAL;
1990         mddev->bitmap_info.max_write_behind = backlog;
1991         return len;
1992 }
1993
1994 static struct md_sysfs_entry bitmap_backlog =
1995 __ATTR(backlog, S_IRUGO|S_IWUSR, backlog_show, backlog_store);
1996
1997 static ssize_t
1998 chunksize_show(struct mddev *mddev, char *page)
1999 {
2000         return sprintf(page, "%lu\n", mddev->bitmap_info.chunksize);
2001 }
2002
2003 static ssize_t
2004 chunksize_store(struct mddev *mddev, const char *buf, size_t len)
2005 {
2006         /* Can only be changed when no bitmap is active */
2007         int rv;
2008         unsigned long csize;
2009         if (mddev->bitmap)
2010                 return -EBUSY;
2011         rv = strict_strtoul(buf, 10, &csize);
2012         if (rv)
2013                 return rv;
2014         if (csize < 512 ||
2015             !is_power_of_2(csize))
2016                 return -EINVAL;
2017         mddev->bitmap_info.chunksize = csize;
2018         return len;
2019 }
2020
2021 static struct md_sysfs_entry bitmap_chunksize =
2022 __ATTR(chunksize, S_IRUGO|S_IWUSR, chunksize_show, chunksize_store);
2023
2024 static ssize_t metadata_show(struct mddev *mddev, char *page)
2025 {
2026         return sprintf(page, "%s\n", (mddev->bitmap_info.external
2027                                       ? "external" : "internal"));
2028 }
2029
2030 static ssize_t metadata_store(struct mddev *mddev, const char *buf, size_t len)
2031 {
2032         if (mddev->bitmap ||
2033             mddev->bitmap_info.file ||
2034             mddev->bitmap_info.offset)
2035                 return -EBUSY;
2036         if (strncmp(buf, "external", 8) == 0)
2037                 mddev->bitmap_info.external = 1;
2038         else if (strncmp(buf, "internal", 8) == 0)
2039                 mddev->bitmap_info.external = 0;
2040         else
2041                 return -EINVAL;
2042         return len;
2043 }
2044
2045 static struct md_sysfs_entry bitmap_metadata =
2046 __ATTR(metadata, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
2047
2048 static ssize_t can_clear_show(struct mddev *mddev, char *page)
2049 {
2050         int len;
2051         if (mddev->bitmap)
2052                 len = sprintf(page, "%s\n", (mddev->bitmap->need_sync ?
2053                                              "false" : "true"));
2054         else
2055                 len = sprintf(page, "\n");
2056         return len;
2057 }
2058
2059 static ssize_t can_clear_store(struct mddev *mddev, const char *buf, size_t len)
2060 {
2061         if (mddev->bitmap == NULL)
2062                 return -ENOENT;
2063         if (strncmp(buf, "false", 5) == 0)
2064                 mddev->bitmap->need_sync = 1;
2065         else if (strncmp(buf, "true", 4) == 0) {
2066                 if (mddev->degraded)
2067                         return -EBUSY;
2068                 mddev->bitmap->need_sync = 0;
2069         } else
2070                 return -EINVAL;
2071         return len;
2072 }
2073
2074 static struct md_sysfs_entry bitmap_can_clear =
2075 __ATTR(can_clear, S_IRUGO|S_IWUSR, can_clear_show, can_clear_store);
2076
2077 static ssize_t
2078 behind_writes_used_show(struct mddev *mddev, char *page)
2079 {
2080         if (mddev->bitmap == NULL)
2081                 return sprintf(page, "0\n");
2082         return sprintf(page, "%lu\n",
2083                        mddev->bitmap->behind_writes_used);
2084 }
2085
2086 static ssize_t
2087 behind_writes_used_reset(struct mddev *mddev, const char *buf, size_t len)
2088 {
2089         if (mddev->bitmap)
2090                 mddev->bitmap->behind_writes_used = 0;
2091         return len;
2092 }
2093
2094 static struct md_sysfs_entry max_backlog_used =
2095 __ATTR(max_backlog_used, S_IRUGO | S_IWUSR,
2096        behind_writes_used_show, behind_writes_used_reset);
2097
2098 static struct attribute *md_bitmap_attrs[] = {
2099         &bitmap_location.attr,
2100         &bitmap_timeout.attr,
2101         &bitmap_backlog.attr,
2102         &bitmap_chunksize.attr,
2103         &bitmap_metadata.attr,
2104         &bitmap_can_clear.attr,
2105         &max_backlog_used.attr,
2106         NULL
2107 };
2108 struct attribute_group md_bitmap_group = {
2109         .name = "bitmap",
2110         .attrs = md_bitmap_attrs,
2111 };
2112