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_counts *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         /* It is possible that this is being called inside a
  76          * prepare_to_wait/finish_wait loop from raid5c:make_request().
  77          * In general it is not permitted to sleep in that context as it
  78          * can cause the loop to spin freely.
  79          * That doesn't apply here as we can only reach this point
  80          * once with any loop.
  81          * When this function completes, either bp[page].map or
  82          * bp[page].hijacked.  In either case, this function will
  83          * abort before getting to this point again.  So there is
  84          * no risk of a free-spin, and so it is safe to assert
  85          * that sleeping here is allowed.
  86          */
  87         sched_annotate_sleep();
  88         mappage = kzalloc(PAGE_SIZE, GFP_NOIO);
  89         spin_lock_irq(&bitmap->lock);
  90
  91         if (mappage == NULL) {
  92                 pr_debug("md/bitmap: map page allocation failed, hijacking\n");
  93                 /* failed - set the hijacked flag so that we can use the
  94                  * pointer as a counter */
  95                 if (!bitmap->bp[page].map)
  96                         bitmap->bp[page].hijacked = 1;
  97         } else if (bitmap->bp[page].map ||
  98                    bitmap->bp[page].hijacked) {
  99                 /* somebody beat us to getting the page */
 100                 kfree(mappage);
 101                 return 0;
 102         } else {
 103
 104                 /* no page was in place and we have one, so install it */
 105
 106                 bitmap->bp[page].map = mappage;
 107                 bitmap->missing_pages--;
 108         }
 109         return 0;
 110 }
 111
 112 /* if page is completely empty, put it back on the free list, or dealloc it */
 113 /* if page was hijacked, unmark the flag so it might get alloced next time */
 114 /* Note: lock should be held when calling this */
 115 static void bitmap_checkfree(struct bitmap_counts *bitmap, unsigned long page)
 116 {
 117         char *ptr;
 118
 119         if (bitmap->bp[page].count) /* page is still busy */
 120                 return;
 121
 122         /* page is no longer in use, it can be released */
 123
 124         if (bitmap->bp[page].hijacked) { /* page was hijacked, undo this now */
 125                 bitmap->bp[page].hijacked = 0;
 126                 bitmap->bp[page].map = NULL;
 127         } else {
 128                 /* normal case, free the page */
 129                 ptr = bitmap->bp[page].map;
 130                 bitmap->bp[page].map = NULL;
 131                 bitmap->missing_pages++;
 132                 kfree(ptr);
 133         }
 134 }
 135
 136 /*
 137  * bitmap file handling - read and write the bitmap file and its superblock
 138  */
 139
 140 /*
 141  * basic page I/O operations
 142  */
 143
 144 /* IO operations when bitmap is stored near all superblocks */
 145 static int read_sb_page(struct mddev *mddev, loff_t offset,
 146                         struct page *page,
 147                         unsigned long index, int size)
 148 {
 149         /* choose a good rdev and read the page from there */
 150
 151         struct md_rdev *rdev;
 152         sector_t target;
 153
 154         rdev_for_each(rdev, mddev) {
 155                 if (! test_bit(In_sync, &rdev->flags)
 156                     || test_bit(Faulty, &rdev->flags))
 157                         continue;
 158
 159                 target = offset + index * (PAGE_SIZE/512);
 160
 161                 if (sync_page_io(rdev, target,
 162                                  roundup(size, bdev_logical_block_size(rdev->bdev)),
 163                                  page, READ, true)) {
 164                         page->index = index;
 165                         return 0;
 166                 }
 167         }
 168         return -EIO;
 169 }
 170
 171 static struct md_rdev *next_active_rdev(struct md_rdev *rdev, struct mddev *mddev)
 172 {
 173         /* Iterate the disks of an mddev, using rcu to protect access to the
 174          * linked list, and raising the refcount of devices we return to ensure
 175          * they don't disappear while in use.
 176          * As devices are only added or removed when raid_disk is < 0 and
 177          * nr_pending is 0 and In_sync is clear, the entries we return will
 178          * still be in the same position on the list when we re-enter
 179          * list_for_each_entry_continue_rcu.
 180          *
 181          * Note that if entered with 'rdev == NULL' to start at the
 182          * beginning, we temporarily assign 'rdev' to an address which
 183          * isn't really an rdev, but which can be used by
 184          * list_for_each_entry_continue_rcu() to find the first entry.
 185          */
 186         rcu_read_lock();
 187         if (rdev == NULL)
 188                 /* start at the beginning */
 189                 rdev = list_entry(&mddev->disks, struct md_rdev, same_set);
 190         else {
 191                 /* release the previous rdev and start from there. */
 192                 rdev_dec_pending(rdev, mddev);
 193         }
 194         list_for_each_entry_continue_rcu(rdev, &mddev->disks, same_set) {
 195                 if (rdev->raid_disk >= 0 &&
 196                     !test_bit(Faulty, &rdev->flags)) {
 197                         /* this is a usable devices */
 198                         atomic_inc(&rdev->nr_pending);
 199                         rcu_read_unlock();
 200                         return rdev;
 201                 }
 202         }
 203         rcu_read_unlock();
 204         return NULL;
 205 }
 206
 207 static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
 208 {
 209         struct md_rdev *rdev = NULL;
 210         struct block_device *bdev;
 211         struct mddev *mddev = bitmap->mddev;
 212         struct bitmap_storage *store = &bitmap->storage;
 213
 214         while ((rdev = next_active_rdev(rdev, mddev)) != NULL) {
 215                 int size = PAGE_SIZE;
 216                 loff_t offset = mddev->bitmap_info.offset;
 217
 218                 bdev = (rdev->meta_bdev) ? rdev->meta_bdev : rdev->bdev;
 219
 220                 if (page->index == store->file_pages-1) {
 221                         int last_page_size = store->bytes & (PAGE_SIZE-1);
 222                         if (last_page_size == 0)
 223                                 last_page_size = PAGE_SIZE;
 224                         size = roundup(last_page_size,
 225                                        bdev_logical_block_size(bdev));
 226                 }
 227                 /* Just make sure we aren't corrupting data or
 228                  * metadata
 229                  */
 230                 if (mddev->external) {
 231                         /* Bitmap could be anywhere. */
 232                         if (rdev->sb_start + offset + (page->index
 233                                                        * (PAGE_SIZE/512))
 234                             > rdev->data_offset
 235                             &&
 236                             rdev->sb_start + offset
 237                             < (rdev->data_offset + mddev->dev_sectors
 238                              + (PAGE_SIZE/512)))
 239                                 goto bad_alignment;
 240                 } else if (offset < 0) {
 241                         /* DATA  BITMAP METADATA  */
 242                         if (offset
 243                             + (long)(page->index * (PAGE_SIZE/512))
 244                             + size/512 > 0)
 245                                 /* bitmap runs in to metadata */
 246                                 goto bad_alignment;
 247                         if (rdev->data_offset + mddev->dev_sectors
 248                             > rdev->sb_start + offset)
 249                                 /* data runs in to bitmap */
 250                                 goto bad_alignment;
 251                 } else if (rdev->sb_start < rdev->data_offset) {
 252                         /* METADATA BITMAP DATA */
 253                         if (rdev->sb_start
 254                             + offset
 255                             + page->index*(PAGE_SIZE/512) + size/512
 256                             > rdev->data_offset)
 257                                 /* bitmap runs in to data */
 258                                 goto bad_alignment;
 259                 } else {
 260                         /* DATA METADATA BITMAP - no problems */
 261                 }
 262                 md_super_write(mddev, rdev,
 263                                rdev->sb_start + offset
 264                                + page->index * (PAGE_SIZE/512),
 265                                size,
 266                                page);
 267         }
 268
 269         if (wait)
 270                 md_super_wait(mddev);
 271         return 0;
 272
 273  bad_alignment:
 274         return -EINVAL;
 275 }
 276
 277 static void bitmap_file_kick(struct bitmap *bitmap);
 278 /*
 279  * write out a page to a file
 280  */
 281 static void write_page(struct bitmap *bitmap, struct page *page, int wait)
 282 {
 283         struct buffer_head *bh;
 284
 285         if (bitmap->storage.file == NULL) {
 286                 switch (write_sb_page(bitmap, page, wait)) {
 287                 case -EINVAL:
 288                         set_bit(BITMAP_WRITE_ERROR, &bitmap->flags);
 289                 }
 290         } else {
 291
 292                 bh = page_buffers(page);
 293
 294                 while (bh && bh->b_blocknr) {
 295                         atomic_inc(&bitmap->pending_writes);
 296                         set_buffer_locked(bh);
 297                         set_buffer_mapped(bh);
 298                         submit_bh(WRITE | REQ_SYNC, bh);
 299                         bh = bh->b_this_page;
 300                 }
 301
 302                 if (wait)
 303                         wait_event(bitmap->write_wait,
 304                                    atomic_read(&bitmap->pending_writes)==0);
 305         }
 306         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
 307                 bitmap_file_kick(bitmap);
 308 }
 309
 310 static void end_bitmap_write(struct buffer_head *bh, int uptodate)
 311 {
 312         struct bitmap *bitmap = bh->b_private;
 313
 314         if (!uptodate)
 315                 set_bit(BITMAP_WRITE_ERROR, &bitmap->flags);
 316         if (atomic_dec_and_test(&bitmap->pending_writes))
 317                 wake_up(&bitmap->write_wait);
 318 }
 319
 320 /* copied from buffer.c */
 321 static void
 322 __clear_page_buffers(struct page *page)
 323 {
 324         ClearPagePrivate(page);
 325         set_page_private(page, 0);
 326         page_cache_release(page);
 327 }
 328 static void free_buffers(struct page *page)
 329 {
 330         struct buffer_head *bh;
 331
 332         if (!PagePrivate(page))
 333                 return;
 334
 335         bh = page_buffers(page);
 336         while (bh) {
 337                 struct buffer_head *next = bh->b_this_page;
 338                 free_buffer_head(bh);
 339                 bh = next;
 340         }
 341         __clear_page_buffers(page);
 342         put_page(page);
 343 }
 344
 345 /* read a page from a file.
 346  * We both read the page, and attach buffers to the page to record the
 347  * address of each block (using bmap).  These addresses will be used
 348  * to write the block later, completely bypassing the filesystem.
 349  * This usage is similar to how swap files are handled, and allows us
 350  * to write to a file with no concerns of memory allocation failing.
 351  */
 352 static int read_page(struct file *file, unsigned long index,
 353                      struct bitmap *bitmap,
 354                      unsigned long count,
 355                      struct page *page)
 356 {
 357         int ret = 0;
 358         struct inode *inode = file_inode(file);
 359         struct buffer_head *bh;
 360         sector_t block;
 361
 362         pr_debug("read bitmap file (%dB @ %llu)\n", (int)PAGE_SIZE,
 363                  (unsigned long long)index << PAGE_SHIFT);
 364
 365         bh = alloc_page_buffers(page, 1<<inode->i_blkbits, 0);
 366         if (!bh) {
 367                 ret = -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                                 ret = -EINVAL;
 380                                 goto out;
 381                         }
 382                         bh->b_bdev = inode->i_sb->s_bdev;
 383                         if (count < (1<<inode->i_blkbits))
 384                                 count = 0;
 385                         else
 386                                 count -= (1<<inode->i_blkbits);
 387
 388                         bh->b_end_io = end_bitmap_write;
 389                         bh->b_private = bitmap;
 390                         atomic_inc(&bitmap->pending_writes);
 391                         set_buffer_locked(bh);
 392                         set_buffer_mapped(bh);
 393                         submit_bh(READ, bh);
 394                 }
 395                 block++;
 396                 bh = bh->b_this_page;
 397         }
 398         page->index = index;
 399
 400         wait_event(bitmap->write_wait,
 401                    atomic_read(&bitmap->pending_writes)==0);
 402         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
 403                 ret = -EIO;
 404 out:
 405         if (ret)
 406                 printk(KERN_ALERT "md: bitmap read error: (%dB @ %llu): %d\n",
 407                         (int)PAGE_SIZE,
 408                         (unsigned long long)index << PAGE_SHIFT,
 409                         ret);
 410         return ret;
 411 }
 412
 413 /*
 414  * bitmap file superblock operations
 415  */
 416
 417 /* update the event counter and sync the superblock to disk */
 418 void bitmap_update_sb(struct bitmap *bitmap)
 419 {
 420         bitmap_super_t *sb;
 421
 422         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
 423                 return;
 424         if (bitmap->mddev->bitmap_info.external)
 425                 return;
 426         if (!bitmap->storage.sb_page) /* no superblock */
 427                 return;
 428         sb = kmap_atomic(bitmap->storage.sb_page);
 429         sb->events = cpu_to_le64(bitmap->mddev->events);
 430         if (bitmap->mddev->events < bitmap->events_cleared)
 431                 /* rocking back to read-only */
 432                 bitmap->events_cleared = bitmap->mddev->events;
 433         sb->events_cleared = cpu_to_le64(bitmap->events_cleared);
 434         sb->state = cpu_to_le32(bitmap->flags);
 435         /* Just in case these have been changed via sysfs: */
 436         sb->daemon_sleep = cpu_to_le32(bitmap->mddev->bitmap_info.daemon_sleep/HZ);
 437         sb->write_behind = cpu_to_le32(bitmap->mddev->bitmap_info.max_write_behind);
 438         /* This might have been changed by a reshape */
 439         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 440         sb->chunksize = cpu_to_le32(bitmap->mddev->bitmap_info.chunksize);
 441         sb->nodes = cpu_to_le32(bitmap->mddev->bitmap_info.nodes);
 442         sb->sectors_reserved = cpu_to_le32(bitmap->mddev->
 443                                            bitmap_info.space);
 444         kunmap_atomic(sb);
 445         write_page(bitmap, bitmap->storage.sb_page, 1);
 446 }
 447
 448 /* print out the bitmap file superblock */
 449 void bitmap_print_sb(struct bitmap *bitmap)
 450 {
 451         bitmap_super_t *sb;
 452
 453         if (!bitmap || !bitmap->storage.sb_page)
 454                 return;
 455         sb = kmap_atomic(bitmap->storage.sb_page);
 456         printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
 457         printk(KERN_DEBUG "         magic: %08x\n", le32_to_cpu(sb->magic));
 458         printk(KERN_DEBUG "       version: %d\n", le32_to_cpu(sb->version));
 459         printk(KERN_DEBUG "          uuid: %08x.%08x.%08x.%08x\n",
 460                                         *(__u32 *)(sb->uuid+0),
 461                                         *(__u32 *)(sb->uuid+4),
 462                                         *(__u32 *)(sb->uuid+8),
 463                                         *(__u32 *)(sb->uuid+12));
 464         printk(KERN_DEBUG "        events: %llu\n",
 465                         (unsigned long long) le64_to_cpu(sb->events));
 466         printk(KERN_DEBUG "events cleared: %llu\n",
 467                         (unsigned long long) le64_to_cpu(sb->events_cleared));
 468         printk(KERN_DEBUG "         state: %08x\n", le32_to_cpu(sb->state));
 469         printk(KERN_DEBUG "     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
 470         printk(KERN_DEBUG "  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
 471         printk(KERN_DEBUG "     sync size: %llu KB\n",
 472                         (unsigned long long)le64_to_cpu(sb->sync_size)/2);
 473         printk(KERN_DEBUG "max write behind: %d\n", le32_to_cpu(sb->write_behind));
 474         kunmap_atomic(sb);
 475 }
 476
 477 /*
 478  * bitmap_new_disk_sb
 479  * @bitmap
 480  *
 481  * This function is somewhat the reverse of bitmap_read_sb.  bitmap_read_sb
 482  * reads and verifies the on-disk bitmap superblock and populates bitmap_info.
 483  * This function verifies 'bitmap_info' and populates the on-disk bitmap
 484  * structure, which is to be written to disk.
 485  *
 486  * Returns: 0 on success, -Exxx on error
 487  */
 488 static int bitmap_new_disk_sb(struct bitmap *bitmap)
 489 {
 490         bitmap_super_t *sb;
 491         unsigned long chunksize, daemon_sleep, write_behind;
 492
 493         bitmap->storage.sb_page = alloc_page(GFP_KERNEL | __GFP_ZERO);
 494         if (bitmap->storage.sb_page == NULL)
 495                 return -ENOMEM;
 496         bitmap->storage.sb_page->index = 0;
 497
 498         sb = kmap_atomic(bitmap->storage.sb_page);
 499
 500         sb->magic = cpu_to_le32(BITMAP_MAGIC);
 501         sb->version = cpu_to_le32(BITMAP_MAJOR_HI);
 502
 503         chunksize = bitmap->mddev->bitmap_info.chunksize;
 504         BUG_ON(!chunksize);
 505         if (!is_power_of_2(chunksize)) {
 506                 kunmap_atomic(sb);
 507                 printk(KERN_ERR "bitmap chunksize not a power of 2\n");
 508                 return -EINVAL;
 509         }
 510         sb->chunksize = cpu_to_le32(chunksize);
 511
 512         daemon_sleep = bitmap->mddev->bitmap_info.daemon_sleep;
 513         if (!daemon_sleep ||
 514             (daemon_sleep < 1) || (daemon_sleep > MAX_SCHEDULE_TIMEOUT)) {
 515                 printk(KERN_INFO "Choosing daemon_sleep default (5 sec)\n");
 516                 daemon_sleep = 5 * HZ;
 517         }
 518         sb->daemon_sleep = cpu_to_le32(daemon_sleep);
 519         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 520
 521         /*
 522          * FIXME: write_behind for RAID1.  If not specified, what
 523          * is a good choice?  We choose COUNTER_MAX / 2 arbitrarily.
 524          */
 525         write_behind = bitmap->mddev->bitmap_info.max_write_behind;
 526         if (write_behind > COUNTER_MAX)
 527                 write_behind = COUNTER_MAX / 2;
 528         sb->write_behind = cpu_to_le32(write_behind);
 529         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 530
 531         /* keep the array size field of the bitmap superblock up to date */
 532         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 533
 534         memcpy(sb->uuid, bitmap->mddev->uuid, 16);
 535
 536         set_bit(BITMAP_STALE, &bitmap->flags);
 537         sb->state = cpu_to_le32(bitmap->flags);
 538         bitmap->events_cleared = bitmap->mddev->events;
 539         sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
 540         bitmap->mddev->bitmap_info.nodes = 0;
 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 nodes = 0;
 555         unsigned long sectors_reserved = 0;
 556         int err = -EINVAL;
 557         struct page *sb_page;
 558         loff_t offset = bitmap->mddev->bitmap_info.offset;
 559
 560         if (!bitmap->storage.file && !bitmap->mddev->bitmap_info.offset) {
 561                 chunksize = 128 * 1024 * 1024;
 562                 daemon_sleep = 5 * HZ;
 563                 write_behind = 0;
 564                 set_bit(BITMAP_STALE, &bitmap->flags);
 565                 err = 0;
 566                 goto out_no_sb;
 567         }
 568         /* page 0 is the superblock, read it... */
 569         sb_page = alloc_page(GFP_KERNEL);
 570         if (!sb_page)
 571                 return -ENOMEM;
 572         bitmap->storage.sb_page = sb_page;
 573
 574 re_read:
 575         /* If cluster_slot is set, the cluster is setup */
 576         if (bitmap->cluster_slot >= 0) {
 577                 sector_t bm_blocks = bitmap->mddev->resync_max_sectors;
 578
 579                 sector_div(bm_blocks,
 580                            bitmap->mddev->bitmap_info.chunksize >> 9);
 581                 /* bits to bytes */
 582                 bm_blocks = ((bm_blocks+7) >> 3) + sizeof(bitmap_super_t);
 583                 /* to 4k blocks */
 584                 bm_blocks = DIV_ROUND_UP_SECTOR_T(bm_blocks, 4096);
 585                 offset = bitmap->mddev->bitmap_info.offset + (bitmap->cluster_slot * (bm_blocks << 3));
 586                 pr_info("%s:%d bm slot: %d offset: %llu\n", __func__, __LINE__,
 587                         bitmap->cluster_slot, offset);
 588         }
 589
 590         if (bitmap->storage.file) {
 591                 loff_t isize = i_size_read(bitmap->storage.file->f_mapping->host);
 592                 int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
 593
 594                 err = read_page(bitmap->storage.file, 0,
 595                                 bitmap, bytes, sb_page);
 596         } else {
 597                 err = read_sb_page(bitmap->mddev,
 598                                    offset,
 599                                    sb_page,
 600                                    0, sizeof(bitmap_super_t));
 601         }
 602         if (err)
 603                 return err;
 604
 605         err = -EINVAL;
 606         sb = kmap_atomic(sb_page);
 607
 608         chunksize = le32_to_cpu(sb->chunksize);
 609         daemon_sleep = le32_to_cpu(sb->daemon_sleep) * HZ;
 610         write_behind = le32_to_cpu(sb->write_behind);
 611         sectors_reserved = le32_to_cpu(sb->sectors_reserved);
 612         /* Setup nodes/clustername only if bitmap version is
 613          * cluster-compatible
 614          */
 615         if (sb->version == cpu_to_le32(BITMAP_MAJOR_CLUSTERED)) {
 616                 nodes = le32_to_cpu(sb->nodes);
 617                 strlcpy(bitmap->mddev->bitmap_info.cluster_name,
 618                                 sb->cluster_name, 64);
 619         }
 620
 621         /* verify that the bitmap-specific fields are valid */
 622         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
 623                 reason = "bad magic";
 624         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
 625                  le32_to_cpu(sb->version) > BITMAP_MAJOR_CLUSTERED)
 626                 reason = "unrecognized superblock version";
 627         else if (chunksize < 512)
 628                 reason = "bitmap chunksize too small";
 629         else if (!is_power_of_2(chunksize))
 630                 reason = "bitmap chunksize not a power of 2";
 631         else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT)
 632                 reason = "daemon sleep period out of range";
 633         else if (write_behind > COUNTER_MAX)
 634                 reason = "write-behind limit out of range (0 - 16383)";
 635         if (reason) {
 636                 printk(KERN_INFO "%s: invalid bitmap file superblock: %s\n",
 637                         bmname(bitmap), reason);
 638                 goto out;
 639         }
 640
 641         /* keep the array size field of the bitmap superblock up to date */
 642         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 643
 644         if (bitmap->mddev->persistent) {
 645                 /*
 646                  * We have a persistent array superblock, so compare the
 647                  * bitmap's UUID and event counter to the mddev's
 648                  */
 649                 if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
 650                         printk(KERN_INFO
 651                                "%s: bitmap superblock UUID mismatch\n",
 652                                bmname(bitmap));
 653                         goto out;
 654                 }
 655                 events = le64_to_cpu(sb->events);
 656                 if (!nodes && (events < bitmap->mddev->events)) {
 657                         printk(KERN_INFO
 658                                "%s: bitmap file is out of date (%llu < %llu) "
 659                                "-- forcing full recovery\n",
 660                                bmname(bitmap), events,
 661                                (unsigned long long) bitmap->mddev->events);
 662                         set_bit(BITMAP_STALE, &bitmap->flags);
 663                 }
 664         }
 665
 666         /* assign fields using values from superblock */
 667         bitmap->flags |= le32_to_cpu(sb->state);
 668         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
 669                 set_bit(BITMAP_HOSTENDIAN, &bitmap->flags);
 670         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
 671         strlcpy(bitmap->mddev->bitmap_info.cluster_name, sb->cluster_name, 64);
 672         err = 0;
 673
 674 out:
 675         kunmap_atomic(sb);
 676         /* Assiging chunksize is required for "re_read" */
 677         bitmap->mddev->bitmap_info.chunksize = chunksize;
 678         if (err == 0 && nodes && (bitmap->cluster_slot < 0)) {
 679                 err = md_setup_cluster(bitmap->mddev, nodes);
 680                 if (err) {
 681                         pr_err("%s: Could not setup cluster service (%d)\n",
 682                                         bmname(bitmap), err);
 683                         goto out_no_sb;
 684                 }
 685                 bitmap->cluster_slot = md_cluster_ops->slot_number(bitmap->mddev);
 686                 goto re_read;
 687         }
 688
 689
 690 out_no_sb:
 691         if (test_bit(BITMAP_STALE, &bitmap->flags))
 692                 bitmap->events_cleared = bitmap->mddev->events;
 693         bitmap->mddev->bitmap_info.chunksize = chunksize;
 694         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 695         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 696         bitmap->mddev->bitmap_info.nodes = nodes;
 697         if (bitmap->mddev->bitmap_info.space == 0 ||
 698             bitmap->mddev->bitmap_info.space > sectors_reserved)
 699                 bitmap->mddev->bitmap_info.space = sectors_reserved;
 700         if (err) {
 701                 bitmap_print_sb(bitmap);
 702                 if (bitmap->cluster_slot < 0)
 703                         md_cluster_stop(bitmap->mddev);
 704         }
 705         return err;
 706 }
 707
 708 /*
 709  * general bitmap file operations
 710  */
 711
 712 /*
 713  * on-disk bitmap:
 714  *
 715  * Use one bit per "chunk" (block set). We do the disk I/O on the bitmap
 716  * file a page at a time. There's a superblock at the start of the file.
 717  */
 718 /* calculate the index of the page that contains this bit */
 719 static inline unsigned long file_page_index(struct bitmap_storage *store,
 720                                             unsigned long chunk)
 721 {
 722         if (store->sb_page)
 723                 chunk += sizeof(bitmap_super_t) << 3;
 724         return chunk >> PAGE_BIT_SHIFT;
 725 }
 726
 727 /* calculate the (bit) offset of this bit within a page */
 728 static inline unsigned long file_page_offset(struct bitmap_storage *store,
 729                                              unsigned long chunk)
 730 {
 731         if (store->sb_page)
 732                 chunk += sizeof(bitmap_super_t) << 3;
 733         return chunk & (PAGE_BITS - 1);
 734 }
 735
 736 /*
 737  * return a pointer to the page in the filemap that contains the given bit
 738  *
 739  */
 740 static inline struct page *filemap_get_page(struct bitmap_storage *store,
 741                                             unsigned long chunk)
 742 {
 743         if (file_page_index(store, chunk) >= store->file_pages)
 744                 return NULL;
 745         return store->filemap[file_page_index(store, chunk)];
 746 }
 747
 748 static int bitmap_storage_alloc(struct bitmap_storage *store,
 749                                 unsigned long chunks, int with_super,
 750                                 int slot_number)
 751 {
 752         int pnum, offset = 0;
 753         unsigned long num_pages;
 754         unsigned long bytes;
 755
 756         bytes = DIV_ROUND_UP(chunks, 8);
 757         if (with_super)
 758                 bytes += sizeof(bitmap_super_t);
 759
 760         num_pages = DIV_ROUND_UP(bytes, PAGE_SIZE);
 761         offset = slot_number * (num_pages - 1);
 762
 763         store->filemap = kmalloc(sizeof(struct page *)
 764                                  * num_pages, GFP_KERNEL);
 765         if (!store->filemap)
 766                 return -ENOMEM;
 767
 768         if (with_super && !store->sb_page) {
 769                 store->sb_page = alloc_page(GFP_KERNEL|__GFP_ZERO);
 770                 if (store->sb_page == NULL)
 771                         return -ENOMEM;
 772         }
 773
 774         pnum = 0;
 775         if (store->sb_page) {
 776                 store->filemap[0] = store->sb_page;
 777                 pnum = 1;
 778                 store->sb_page->index = offset;
 779         }
 780
 781         for ( ; pnum < num_pages; pnum++) {
 782                 store->filemap[pnum] = alloc_page(GFP_KERNEL|__GFP_ZERO);
 783                 if (!store->filemap[pnum]) {
 784                         store->file_pages = pnum;
 785                         return -ENOMEM;
 786                 }
 787                 store->filemap[pnum]->index = pnum + offset;
 788         }
 789         store->file_pages = pnum;
 790
 791         /* We need 4 bits per page, rounded up to a multiple
 792          * of sizeof(unsigned long) */
 793         store->filemap_attr = kzalloc(
 794                 roundup(DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
 795                 GFP_KERNEL);
 796         if (!store->filemap_attr)
 797                 return -ENOMEM;
 798
 799         store->bytes = bytes;
 800
 801         return 0;
 802 }
 803
 804 static void bitmap_file_unmap(struct bitmap_storage *store)
 805 {
 806         struct page **map, *sb_page;
 807         int pages;
 808         struct file *file;
 809
 810         file = store->file;
 811         map = store->filemap;
 812         pages = store->file_pages;
 813         sb_page = store->sb_page;
 814
 815         while (pages--)
 816                 if (map[pages] != sb_page) /* 0 is sb_page, release it below */
 817                         free_buffers(map[pages]);
 818         kfree(map);
 819         kfree(store->filemap_attr);
 820
 821         if (sb_page)
 822                 free_buffers(sb_page);
 823
 824         if (file) {
 825                 struct inode *inode = file_inode(file);
 826                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
 827                 fput(file);
 828         }
 829 }
 830
 831 /*
 832  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
 833  * then it is no longer reliable, so we stop using it and we mark the file
 834  * as failed in the superblock
 835  */
 836 static void bitmap_file_kick(struct bitmap *bitmap)
 837 {
 838         char *path, *ptr = NULL;
 839
 840         if (!test_and_set_bit(BITMAP_STALE, &bitmap->flags)) {
 841                 bitmap_update_sb(bitmap);
 842
 843                 if (bitmap->storage.file) {
 844                         path = kmalloc(PAGE_SIZE, GFP_KERNEL);
 845                         if (path)
 846                                 ptr = file_path(bitmap->storage.file,
 847                                              path, PAGE_SIZE);
 848
 849                         printk(KERN_ALERT
 850                               "%s: kicking failed bitmap file %s from array!\n",
 851                               bmname(bitmap), IS_ERR(ptr) ? "" : ptr);
 852
 853                         kfree(path);
 854                 } else
 855                         printk(KERN_ALERT
 856                                "%s: disabling internal bitmap due to errors\n",
 857                                bmname(bitmap));
 858         }
 859 }
 860
 861 enum bitmap_page_attr {
 862         BITMAP_PAGE_DIRTY = 0,     /* there are set bits that need to be synced */
 863         BITMAP_PAGE_PENDING = 1,   /* there are bits that are being cleaned.
 864                                     * i.e. counter is 1 or 2. */
 865         BITMAP_PAGE_NEEDWRITE = 2, /* there are cleared bits that need to be synced */
 866 };
 867
 868 static inline void set_page_attr(struct bitmap *bitmap, int pnum,
 869                                  enum bitmap_page_attr attr)
 870 {
 871         set_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 872 }
 873
 874 static inline void clear_page_attr(struct bitmap *bitmap, int pnum,
 875                                    enum bitmap_page_attr attr)
 876 {
 877         clear_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 878 }
 879
 880 static inline int test_page_attr(struct bitmap *bitmap, int pnum,
 881                                  enum bitmap_page_attr attr)
 882 {
 883         return test_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 884 }
 885
 886 static inline int test_and_clear_page_attr(struct bitmap *bitmap, int pnum,
 887                                            enum bitmap_page_attr attr)
 888 {
 889         return test_and_clear_bit((pnum<<2) + attr,
 890                                   bitmap->storage.filemap_attr);
 891 }
 892 /*
 893  * bitmap_file_set_bit -- called before performing a write to the md device
 894  * to set (and eventually sync) a particular bit in the bitmap file
 895  *
 896  * we set the bit immediately, then we record the page number so that
 897  * when an unplug occurs, we can flush the dirty pages out to disk
 898  */
 899 static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 900 {
 901         unsigned long bit;
 902         struct page *page;
 903         void *kaddr;
 904         unsigned long chunk = block >> bitmap->counts.chunkshift;
 905
 906         page = filemap_get_page(&bitmap->storage, chunk);
 907         if (!page)
 908                 return;
 909         bit = file_page_offset(&bitmap->storage, chunk);
 910
 911         /* set the bit */
 912         kaddr = kmap_atomic(page);
 913         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
 914                 set_bit(bit, kaddr);
 915         else
 916                 set_bit_le(bit, kaddr);
 917         kunmap_atomic(kaddr);
 918         pr_debug("set file bit %lu page %lu\n", bit, page->index);
 919         /* record page number so it gets flushed to disk when unplug occurs */
 920         set_page_attr(bitmap, page->index, BITMAP_PAGE_DIRTY);
 921 }
 922
 923 static void bitmap_file_clear_bit(struct bitmap *bitmap, sector_t block)
 924 {
 925         unsigned long bit;
 926         struct page *page;
 927         void *paddr;
 928         unsigned long chunk = block >> bitmap->counts.chunkshift;
 929
 930         page = filemap_get_page(&bitmap->storage, chunk);
 931         if (!page)
 932                 return;
 933         bit = file_page_offset(&bitmap->storage, chunk);
 934         paddr = kmap_atomic(page);
 935         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
 936                 clear_bit(bit, paddr);
 937         else
 938                 clear_bit_le(bit, paddr);
 939         kunmap_atomic(paddr);
 940         if (!test_page_attr(bitmap, page->index, BITMAP_PAGE_NEEDWRITE)) {
 941                 set_page_attr(bitmap, page->index, BITMAP_PAGE_PENDING);
 942                 bitmap->allclean = 0;
 943         }
 944 }
 945
 946 static int bitmap_file_test_bit(struct bitmap *bitmap, sector_t block)
 947 {
 948         unsigned long bit;
 949         struct page *page;
 950         void *paddr;
 951         unsigned long chunk = block >> bitmap->counts.chunkshift;
 952         int set = 0;
 953
 954         page = filemap_get_page(&bitmap->storage, chunk);
 955         if (!page)
 956                 return -EINVAL;
 957         bit = file_page_offset(&bitmap->storage, chunk);
 958         paddr = kmap_atomic(page);
 959         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
 960                 set = test_bit(bit, paddr);
 961         else
 962                 set = test_bit_le(bit, paddr);
 963         kunmap_atomic(paddr);
 964         return set;
 965 }
 966
 967
 968 /* this gets called when the md device is ready to unplug its underlying
 969  * (slave) device queues -- before we let any writes go down, we need to
 970  * sync the dirty pages of the bitmap file to disk */
 971 void bitmap_unplug(struct bitmap *bitmap)
 972 {
 973         unsigned long i;
 974         int dirty, need_write;
 975
 976         if (!bitmap || !bitmap->storage.filemap ||
 977             test_bit(BITMAP_STALE, &bitmap->flags))
 978                 return;
 979
 980         /* look at each page to see if there are any set bits that need to be
 981          * flushed out to disk */
 982         for (i = 0; i < bitmap->storage.file_pages; i++) {
 983                 if (!bitmap->storage.filemap)
 984                         return;
 985                 dirty = test_and_clear_page_attr(bitmap, i, BITMAP_PAGE_DIRTY);
 986                 need_write = test_and_clear_page_attr(bitmap, i,
 987                                                       BITMAP_PAGE_NEEDWRITE);
 988                 if (dirty || need_write) {
 989                         clear_page_attr(bitmap, i, BITMAP_PAGE_PENDING);
 990                         write_page(bitmap, bitmap->storage.filemap[i], 0);
 991                 }
 992         }
 993         if (bitmap->storage.file)
 994                 wait_event(bitmap->write_wait,
 995                            atomic_read(&bitmap->pending_writes)==0);
 996         else
 997                 md_super_wait(bitmap->mddev);
 998
 999         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
1000                 bitmap_file_kick(bitmap);
1001 }
1002 EXPORT_SYMBOL(bitmap_unplug);
1003
1004 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
1005 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
1006  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
1007  * memory mapping of the bitmap file
1008  * Special cases:
1009  *   if there's no bitmap file, or if the bitmap file had been
1010  *   previously kicked from the array, we mark all the bits as
1011  *   1's in order to cause a full resync.
1012  *
1013  * We ignore all bits for sectors that end earlier than 'start'.
1014  * This is used when reading an out-of-date bitmap...
1015  */
1016 static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
1017 {
1018         unsigned long i, chunks, index, oldindex, bit, node_offset = 0;
1019         struct page *page = NULL;
1020         unsigned long bit_cnt = 0;
1021         struct file *file;
1022         unsigned long offset;
1023         int outofdate;
1024         int ret = -ENOSPC;
1025         void *paddr;
1026         struct bitmap_storage *store = &bitmap->storage;
1027
1028         chunks = bitmap->counts.chunks;
1029         file = store->file;
1030
1031         if (!file && !bitmap->mddev->bitmap_info.offset) {
1032                 /* No permanent bitmap - fill with '1s'. */
1033                 store->filemap = NULL;
1034                 store->file_pages = 0;
1035                 for (i = 0; i < chunks ; i++) {
1036                         /* if the disk bit is set, set the memory bit */
1037                         int needed = ((sector_t)(i+1) << (bitmap->counts.chunkshift)
1038                                       >= start);
1039                         bitmap_set_memory_bits(bitmap,
1040                                                (sector_t)i << bitmap->counts.chunkshift,
1041                                                needed);
1042                 }
1043                 return 0;
1044         }
1045
1046         outofdate = test_bit(BITMAP_STALE, &bitmap->flags);
1047         if (outofdate)
1048                 printk(KERN_INFO "%s: bitmap file is out of date, doing full "
1049                         "recovery\n", bmname(bitmap));
1050
1051         if (file && i_size_read(file->f_mapping->host) < store->bytes) {
1052                 printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
1053                        bmname(bitmap),
1054                        (unsigned long) i_size_read(file->f_mapping->host),
1055                        store->bytes);
1056                 goto err;
1057         }
1058
1059         oldindex = ~0L;
1060         offset = 0;
1061         if (!bitmap->mddev->bitmap_info.external)
1062                 offset = sizeof(bitmap_super_t);
1063
1064         if (mddev_is_clustered(bitmap->mddev))
1065                 node_offset = bitmap->cluster_slot * (DIV_ROUND_UP(store->bytes, PAGE_SIZE));
1066
1067         for (i = 0; i < chunks; i++) {
1068                 int b;
1069                 index = file_page_index(&bitmap->storage, i);
1070                 bit = file_page_offset(&bitmap->storage, i);
1071                 if (index != oldindex) { /* this is a new page, read it in */
1072                         int count;
1073                         /* unmap the old page, we're done with it */
1074                         if (index == store->file_pages-1)
1075                                 count = store->bytes - index * PAGE_SIZE;
1076                         else
1077                                 count = PAGE_SIZE;
1078                         page = store->filemap[index];
1079                         if (file)
1080                                 ret = read_page(file, index, bitmap,
1081                                                 count, page);
1082                         else
1083                                 ret = read_sb_page(
1084                                         bitmap->mddev,
1085                                         bitmap->mddev->bitmap_info.offset,
1086                                         page,
1087                                         index + node_offset, count);
1088
1089                         if (ret)
1090                                 goto err;
1091
1092                         oldindex = index;
1093
1094                         if (outofdate) {
1095                                 /*
1096                                  * if bitmap is out of date, dirty the
1097                                  * whole page and write it out
1098                                  */
1099                                 paddr = kmap_atomic(page);
1100                                 memset(paddr + offset, 0xff,
1101                                        PAGE_SIZE - offset);
1102                                 kunmap_atomic(paddr);
1103                                 write_page(bitmap, page, 1);
1104
1105                                 ret = -EIO;
1106                                 if (test_bit(BITMAP_WRITE_ERROR,
1107                                              &bitmap->flags))
1108                                         goto err;
1109                         }
1110                 }
1111                 paddr = kmap_atomic(page);
1112                 if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
1113                         b = test_bit(bit, paddr);
1114                 else
1115                         b = test_bit_le(bit, paddr);
1116                 kunmap_atomic(paddr);
1117                 if (b) {
1118                         /* if the disk bit is set, set the memory bit */
1119                         int needed = ((sector_t)(i+1) << bitmap->counts.chunkshift
1120                                       >= start);
1121                         bitmap_set_memory_bits(bitmap,
1122                                                (sector_t)i << bitmap->counts.chunkshift,
1123                                                needed);
1124                         bit_cnt++;
1125                 }
1126                 offset = 0;
1127         }
1128
1129         printk(KERN_INFO "%s: bitmap initialized from disk: "
1130                "read %lu pages, set %lu of %lu bits\n",
1131                bmname(bitmap), store->file_pages,
1132                bit_cnt, chunks);
1133
1134         return 0;
1135
1136  err:
1137         printk(KERN_INFO "%s: bitmap initialisation failed: %d\n",
1138                bmname(bitmap), ret);
1139         return ret;
1140 }
1141
1142 void bitmap_write_all(struct bitmap *bitmap)
1143 {
1144         /* We don't actually write all bitmap blocks here,
1145          * just flag them as needing to be written
1146          */
1147         int i;
1148
1149         if (!bitmap || !bitmap->storage.filemap)
1150                 return;
1151         if (bitmap->storage.file)
1152                 /* Only one copy, so nothing needed */
1153                 return;
1154
1155         for (i = 0; i < bitmap->storage.file_pages; i++)
1156                 set_page_attr(bitmap, i,
1157                               BITMAP_PAGE_NEEDWRITE);
1158         bitmap->allclean = 0;
1159 }
1160
1161 static void bitmap_count_page(struct bitmap_counts *bitmap,
1162                               sector_t offset, int inc)
1163 {
1164         sector_t chunk = offset >> bitmap->chunkshift;
1165         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1166         bitmap->bp[page].count += inc;
1167         bitmap_checkfree(bitmap, page);
1168 }
1169
1170 static void bitmap_set_pending(struct bitmap_counts *bitmap, sector_t offset)
1171 {
1172         sector_t chunk = offset >> bitmap->chunkshift;
1173         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1174         struct bitmap_page *bp = &bitmap->bp[page];
1175
1176         if (!bp->pending)
1177                 bp->pending = 1;
1178 }
1179
1180 static bitmap_counter_t *bitmap_get_counter(struct bitmap_counts *bitmap,
1181                                             sector_t offset, sector_t *blocks,
1182                                             int create);
1183
1184 /*
1185  * bitmap daemon -- periodically wakes up to clean bits and flush pages
1186  *                      out to disk
1187  */
1188
1189 void bitmap_daemon_work(struct mddev *mddev)
1190 {
1191         struct bitmap *bitmap;
1192         unsigned long j;
1193         unsigned long nextpage;
1194         sector_t blocks;
1195         struct bitmap_counts *counts;
1196
1197         /* Use a mutex to guard daemon_work against
1198          * bitmap_destroy.
1199          */
1200         mutex_lock(&mddev->bitmap_info.mutex);
1201         bitmap = mddev->bitmap;
1202         if (bitmap == NULL) {
1203                 mutex_unlock(&mddev->bitmap_info.mutex);
1204                 return;
1205         }
1206         if (time_before(jiffies, bitmap->daemon_lastrun
1207                         + mddev->bitmap_info.daemon_sleep))
1208                 goto done;
1209
1210         bitmap->daemon_lastrun = jiffies;
1211         if (bitmap->allclean) {
1212                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1213                 goto done;
1214         }
1215         bitmap->allclean = 1;
1216
1217         /* Any file-page which is PENDING now needs to be written.
1218          * So set NEEDWRITE now, then after we make any last-minute changes
1219          * we will write it.
1220          */
1221         for (j = 0; j < bitmap->storage.file_pages; j++)
1222                 if (test_and_clear_page_attr(bitmap, j,
1223                                              BITMAP_PAGE_PENDING))
1224                         set_page_attr(bitmap, j,
1225                                       BITMAP_PAGE_NEEDWRITE);
1226
1227         if (bitmap->need_sync &&
1228             mddev->bitmap_info.external == 0) {
1229                 /* Arrange for superblock update as well as
1230                  * other changes */
1231                 bitmap_super_t *sb;
1232                 bitmap->need_sync = 0;
1233                 if (bitmap->storage.filemap) {
1234                         sb = kmap_atomic(bitmap->storage.sb_page);
1235                         sb->events_cleared =
1236                                 cpu_to_le64(bitmap->events_cleared);
1237                         kunmap_atomic(sb);
1238                         set_page_attr(bitmap, 0,
1239                                       BITMAP_PAGE_NEEDWRITE);
1240                 }
1241         }
1242         /* Now look at the bitmap counters and if any are '2' or '1',
1243          * decrement and handle accordingly.
1244          */
1245         counts = &bitmap->counts;
1246         spin_lock_irq(&counts->lock);
1247         nextpage = 0;
1248         for (j = 0; j < counts->chunks; j++) {
1249                 bitmap_counter_t *bmc;
1250                 sector_t  block = (sector_t)j << counts->chunkshift;
1251
1252                 if (j == nextpage) {
1253                         nextpage += PAGE_COUNTER_RATIO;
1254                         if (!counts->bp[j >> PAGE_COUNTER_SHIFT].pending) {
1255                                 j |= PAGE_COUNTER_MASK;
1256                                 continue;
1257                         }
1258                         counts->bp[j >> PAGE_COUNTER_SHIFT].pending = 0;
1259                 }
1260                 bmc = bitmap_get_counter(counts,
1261                                          block,
1262                                          &blocks, 0);
1263
1264                 if (!bmc) {
1265                         j |= PAGE_COUNTER_MASK;
1266                         continue;
1267                 }
1268                 if (*bmc == 1 && !bitmap->need_sync) {
1269                         /* We can clear the bit */
1270                         *bmc = 0;
1271                         bitmap_count_page(counts, block, -1);
1272                         bitmap_file_clear_bit(bitmap, block);
1273                 } else if (*bmc && *bmc <= 2) {
1274                         *bmc = 1;
1275                         bitmap_set_pending(counts, block);
1276                         bitmap->allclean = 0;
1277                 }
1278         }
1279         spin_unlock_irq(&counts->lock);
1280
1281         /* Now start writeout on any page in NEEDWRITE that isn't DIRTY.
1282          * DIRTY pages need to be written by bitmap_unplug so it can wait
1283          * for them.
1284          * If we find any DIRTY page we stop there and let bitmap_unplug
1285          * handle all the rest.  This is important in the case where
1286          * the first blocking holds the superblock and it has been updated.
1287          * We mustn't write any other blocks before the superblock.
1288          */
1289         for (j = 0;
1290              j < bitmap->storage.file_pages
1291                      && !test_bit(BITMAP_STALE, &bitmap->flags);
1292              j++) {
1293                 if (test_page_attr(bitmap, j,
1294                                    BITMAP_PAGE_DIRTY))
1295                         /* bitmap_unplug will handle the rest */
1296                         break;
1297                 if (test_and_clear_page_attr(bitmap, j,
1298                                              BITMAP_PAGE_NEEDWRITE)) {
1299                         write_page(bitmap, bitmap->storage.filemap[j], 0);
1300                 }
1301         }
1302
1303  done:
1304         if (bitmap->allclean == 0)
1305                 mddev->thread->timeout =
1306                         mddev->bitmap_info.daemon_sleep;
1307         mutex_unlock(&mddev->bitmap_info.mutex);
1308 }
1309
1310 static bitmap_counter_t *bitmap_get_counter(struct bitmap_counts *bitmap,
1311                                             sector_t offset, sector_t *blocks,
1312                                             int create)
1313 __releases(bitmap->lock)
1314 __acquires(bitmap->lock)
1315 {
1316         /* If 'create', we might release the lock and reclaim it.
1317          * The lock must have been taken with interrupts enabled.
1318          * If !create, we don't release the lock.
1319          */
1320         sector_t chunk = offset >> bitmap->chunkshift;
1321         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1322         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1323         sector_t csize;
1324         int err;
1325
1326         err = bitmap_checkpage(bitmap, page, create);
1327
1328         if (bitmap->bp[page].hijacked ||
1329             bitmap->bp[page].map == NULL)
1330                 csize = ((sector_t)1) << (bitmap->chunkshift +
1331                                           PAGE_COUNTER_SHIFT - 1);
1332         else
1333                 csize = ((sector_t)1) << bitmap->chunkshift;
1334         *blocks = csize - (offset & (csize - 1));
1335
1336         if (err < 0)
1337                 return NULL;
1338
1339         /* now locked ... */
1340
1341         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1342                 /* should we use the first or second counter field
1343                  * of the hijacked pointer? */
1344                 int hi = (pageoff > PAGE_COUNTER_MASK);
1345                 return  &((bitmap_counter_t *)
1346                           &bitmap->bp[page].map)[hi];
1347         } else /* page is allocated */
1348                 return (bitmap_counter_t *)
1349                         &(bitmap->bp[page].map[pageoff]);
1350 }
1351
1352 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1353 {
1354         if (!bitmap)
1355                 return 0;
1356
1357         if (behind) {
1358                 int bw;
1359                 atomic_inc(&bitmap->behind_writes);
1360                 bw = atomic_read(&bitmap->behind_writes);
1361                 if (bw > bitmap->behind_writes_used)
1362                         bitmap->behind_writes_used = bw;
1363
1364                 pr_debug("inc write-behind count %d/%lu\n",
1365                          bw, bitmap->mddev->bitmap_info.max_write_behind);
1366         }
1367
1368         while (sectors) {
1369                 sector_t blocks;
1370                 bitmap_counter_t *bmc;
1371
1372                 spin_lock_irq(&bitmap->counts.lock);
1373                 bmc = bitmap_get_counter(&bitmap->counts, offset, &blocks, 1);
1374                 if (!bmc) {
1375                         spin_unlock_irq(&bitmap->counts.lock);
1376                         return 0;
1377                 }
1378
1379                 if (unlikely(COUNTER(*bmc) == COUNTER_MAX)) {
1380                         DEFINE_WAIT(__wait);
1381                         /* note that it is safe to do the prepare_to_wait
1382                          * after the test as long as we do it before dropping
1383                          * the spinlock.
1384                          */
1385                         prepare_to_wait(&bitmap->overflow_wait, &__wait,
1386                                         TASK_UNINTERRUPTIBLE);
1387                         spin_unlock_irq(&bitmap->counts.lock);
1388                         schedule();
1389                         finish_wait(&bitmap->overflow_wait, &__wait);
1390                         continue;
1391                 }
1392
1393                 switch (*bmc) {
1394                 case 0:
1395                         bitmap_file_set_bit(bitmap, offset);
1396                         bitmap_count_page(&bitmap->counts, offset, 1);
1397                         /* fall through */
1398                 case 1:
1399                         *bmc = 2;
1400                 }
1401
1402                 (*bmc)++;
1403
1404                 spin_unlock_irq(&bitmap->counts.lock);
1405
1406                 offset += blocks;
1407                 if (sectors > blocks)
1408                         sectors -= blocks;
1409                 else
1410                         sectors = 0;
1411         }
1412         return 0;
1413 }
1414 EXPORT_SYMBOL(bitmap_startwrite);
1415
1416 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1417                      int success, int behind)
1418 {
1419         if (!bitmap)
1420                 return;
1421         if (behind) {
1422                 if (atomic_dec_and_test(&bitmap->behind_writes))
1423                         wake_up(&bitmap->behind_wait);
1424                 pr_debug("dec write-behind count %d/%lu\n",
1425                          atomic_read(&bitmap->behind_writes),
1426                          bitmap->mddev->bitmap_info.max_write_behind);
1427         }
1428
1429         while (sectors) {
1430                 sector_t blocks;
1431                 unsigned long flags;
1432                 bitmap_counter_t *bmc;
1433
1434                 spin_lock_irqsave(&bitmap->counts.lock, flags);
1435                 bmc = bitmap_get_counter(&bitmap->counts, offset, &blocks, 0);
1436                 if (!bmc) {
1437                         spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1438                         return;
1439                 }
1440
1441                 if (success && !bitmap->mddev->degraded &&
1442                     bitmap->events_cleared < bitmap->mddev->events) {
1443                         bitmap->events_cleared = bitmap->mddev->events;
1444                         bitmap->need_sync = 1;
1445                         sysfs_notify_dirent_safe(bitmap->sysfs_can_clear);
1446                 }
1447
1448                 if (!success && !NEEDED(*bmc))
1449                         *bmc |= NEEDED_MASK;
1450
1451                 if (COUNTER(*bmc) == COUNTER_MAX)
1452                         wake_up(&bitmap->overflow_wait);
1453
1454                 (*bmc)--;
1455                 if (*bmc <= 2) {
1456                         bitmap_set_pending(&bitmap->counts, offset);
1457                         bitmap->allclean = 0;
1458                 }
1459                 spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1460                 offset += blocks;
1461                 if (sectors > blocks)
1462                         sectors -= blocks;
1463                 else
1464                         sectors = 0;
1465         }
1466 }
1467 EXPORT_SYMBOL(bitmap_endwrite);
1468
1469 static int __bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1470                                int degraded)
1471 {
1472         bitmap_counter_t *bmc;
1473         int rv;
1474         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1475                 *blocks = 1024;
1476                 return 1; /* always resync if no bitmap */
1477         }
1478         spin_lock_irq(&bitmap->counts.lock);
1479         bmc = bitmap_get_counter(&bitmap->counts, offset, blocks, 0);
1480         rv = 0;
1481         if (bmc) {
1482                 /* locked */
1483                 if (RESYNC(*bmc))
1484                         rv = 1;
1485                 else if (NEEDED(*bmc)) {
1486                         rv = 1;
1487                         if (!degraded) { /* don't set/clear bits if degraded */
1488                                 *bmc |= RESYNC_MASK;
1489                                 *bmc &= ~NEEDED_MASK;
1490                         }
1491                 }
1492         }
1493         spin_unlock_irq(&bitmap->counts.lock);
1494         return rv;
1495 }
1496
1497 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1498                       int degraded)
1499 {
1500         /* bitmap_start_sync must always report on multiples of whole
1501          * pages, otherwise resync (which is very PAGE_SIZE based) will
1502          * get confused.
1503          * So call __bitmap_start_sync repeatedly (if needed) until
1504          * At least PAGE_SIZE>>9 blocks are covered.
1505          * Return the 'or' of the result.
1506          */
1507         int rv = 0;
1508         sector_t blocks1;
1509
1510         *blocks = 0;
1511         while (*blocks < (PAGE_SIZE>>9)) {
1512                 rv |= __bitmap_start_sync(bitmap, offset,
1513                                           &blocks1, degraded);
1514                 offset += blocks1;
1515                 *blocks += blocks1;
1516         }
1517         return rv;
1518 }
1519 EXPORT_SYMBOL(bitmap_start_sync);
1520
1521 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks, int aborted)
1522 {
1523         bitmap_counter_t *bmc;
1524         unsigned long flags;
1525
1526         if (bitmap == NULL) {
1527                 *blocks = 1024;
1528                 return;
1529         }
1530         spin_lock_irqsave(&bitmap->counts.lock, flags);
1531         bmc = bitmap_get_counter(&bitmap->counts, offset, blocks, 0);
1532         if (bmc == NULL)
1533                 goto unlock;
1534         /* locked */
1535         if (RESYNC(*bmc)) {
1536                 *bmc &= ~RESYNC_MASK;
1537
1538                 if (!NEEDED(*bmc) && aborted)
1539                         *bmc |= NEEDED_MASK;
1540                 else {
1541                         if (*bmc <= 2) {
1542                                 bitmap_set_pending(&bitmap->counts, offset);
1543                                 bitmap->allclean = 0;
1544                         }
1545                 }
1546         }
1547  unlock:
1548         spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1549 }
1550 EXPORT_SYMBOL(bitmap_end_sync);
1551
1552 void bitmap_close_sync(struct bitmap *bitmap)
1553 {
1554         /* Sync has finished, and any bitmap chunks that weren't synced
1555          * properly have been aborted.  It remains to us to clear the
1556          * RESYNC bit wherever it is still on
1557          */
1558         sector_t sector = 0;
1559         sector_t blocks;
1560         if (!bitmap)
1561                 return;
1562         while (sector < bitmap->mddev->resync_max_sectors) {
1563                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1564                 sector += blocks;
1565         }
1566 }
1567 EXPORT_SYMBOL(bitmap_close_sync);
1568
1569 void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector, bool force)
1570 {
1571         sector_t s = 0;
1572         sector_t blocks;
1573
1574         if (!bitmap)
1575                 return;
1576         if (sector == 0) {
1577                 bitmap->last_end_sync = jiffies;
1578                 return;
1579         }
1580         if (!force && time_before(jiffies, (bitmap->last_end_sync
1581                                   + bitmap->mddev->bitmap_info.daemon_sleep)))
1582                 return;
1583         wait_event(bitmap->mddev->recovery_wait,
1584                    atomic_read(&bitmap->mddev->recovery_active) == 0);
1585
1586         bitmap->mddev->curr_resync_completed = sector;
1587         set_bit(MD_CHANGE_CLEAN, &bitmap->mddev->flags);
1588         sector &= ~((1ULL << bitmap->counts.chunkshift) - 1);
1589         s = 0;
1590         while (s < sector && s < bitmap->mddev->resync_max_sectors) {
1591                 bitmap_end_sync(bitmap, s, &blocks, 0);
1592                 s += blocks;
1593         }
1594         bitmap->last_end_sync = jiffies;
1595         sysfs_notify(&bitmap->mddev->kobj, NULL, "sync_completed");
1596 }
1597 EXPORT_SYMBOL(bitmap_cond_end_sync);
1598
1599 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1600 {
1601         /* For each chunk covered by any of these sectors, set the
1602          * counter to 2 and possibly set resync_needed.  They should all
1603          * be 0 at this point
1604          */
1605
1606         sector_t secs;
1607         bitmap_counter_t *bmc;
1608         spin_lock_irq(&bitmap->counts.lock);
1609         bmc = bitmap_get_counter(&bitmap->counts, offset, &secs, 1);
1610         if (!bmc) {
1611                 spin_unlock_irq(&bitmap->counts.lock);
1612                 return;
1613         }
1614         if (!*bmc) {
1615                 *bmc = 2;
1616                 bitmap_count_page(&bitmap->counts, offset, 1);
1617                 bitmap_set_pending(&bitmap->counts, offset);
1618                 bitmap->allclean = 0;
1619         }
1620         if (needed)
1621                 *bmc |= NEEDED_MASK;
1622         spin_unlock_irq(&bitmap->counts.lock);
1623 }
1624
1625 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
1626 void bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1627 {
1628         unsigned long chunk;
1629
1630         for (chunk = s; chunk <= e; chunk++) {
1631                 sector_t sec = (sector_t)chunk << bitmap->counts.chunkshift;
1632                 bitmap_set_memory_bits(bitmap, sec, 1);
1633                 bitmap_file_set_bit(bitmap, sec);
1634                 if (sec < bitmap->mddev->recovery_cp)
1635                         /* We are asserting that the array is dirty,
1636                          * so move the recovery_cp address back so
1637                          * that it is obvious that it is dirty
1638                          */
1639                         bitmap->mddev->recovery_cp = sec;
1640         }
1641 }
1642
1643 /*
1644  * flush out any pending updates
1645  */
1646 void bitmap_flush(struct mddev *mddev)
1647 {
1648         struct bitmap *bitmap = mddev->bitmap;
1649         long sleep;
1650
1651         if (!bitmap) /* there was no bitmap */
1652                 return;
1653
1654         /* run the daemon_work three time to ensure everything is flushed
1655          * that can be
1656          */
1657         sleep = mddev->bitmap_info.daemon_sleep * 2;
1658         bitmap->daemon_lastrun -= sleep;
1659         bitmap_daemon_work(mddev);
1660         bitmap->daemon_lastrun -= sleep;
1661         bitmap_daemon_work(mddev);
1662         bitmap->daemon_lastrun -= sleep;
1663         bitmap_daemon_work(mddev);
1664         bitmap_update_sb(bitmap);
1665 }
1666
1667 /*
1668  * free memory that was allocated
1669  */
1670 static void bitmap_free(struct bitmap *bitmap)
1671 {
1672         unsigned long k, pages;
1673         struct bitmap_page *bp;
1674
1675         if (!bitmap) /* there was no bitmap */
1676                 return;
1677
1678         if (mddev_is_clustered(bitmap->mddev) && bitmap->mddev->cluster_info &&
1679                 bitmap->cluster_slot == md_cluster_ops->slot_number(bitmap->mddev))
1680                 md_cluster_stop(bitmap->mddev);
1681
1682         /* Shouldn't be needed - but just in case.... */
1683         wait_event(bitmap->write_wait,
1684                    atomic_read(&bitmap->pending_writes) == 0);
1685
1686         /* release the bitmap file  */
1687         bitmap_file_unmap(&bitmap->storage);
1688
1689         bp = bitmap->counts.bp;
1690         pages = bitmap->counts.pages;
1691
1692         /* free all allocated memory */
1693
1694         if (bp) /* deallocate the page memory */
1695                 for (k = 0; k < pages; k++)
1696                         if (bp[k].map && !bp[k].hijacked)
1697                                 kfree(bp[k].map);
1698         kfree(bp);
1699         kfree(bitmap);
1700 }
1701
1702 void bitmap_destroy(struct mddev *mddev)
1703 {
1704         struct bitmap *bitmap = mddev->bitmap;
1705
1706         if (!bitmap) /* there was no bitmap */
1707                 return;
1708
1709         mutex_lock(&mddev->bitmap_info.mutex);
1710         spin_lock(&mddev->lock);
1711         mddev->bitmap = NULL; /* disconnect from the md device */
1712         spin_unlock(&mddev->lock);
1713         mutex_unlock(&mddev->bitmap_info.mutex);
1714         if (mddev->thread)
1715                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1716
1717         if (bitmap->sysfs_can_clear)
1718                 sysfs_put(bitmap->sysfs_can_clear);
1719
1720         bitmap_free(bitmap);
1721 }
1722
1723 /*
1724  * initialize the bitmap structure
1725  * if this returns an error, bitmap_destroy must be called to do clean up
1726  */
1727 struct bitmap *bitmap_create(struct mddev *mddev, int slot)
1728 {
1729         struct bitmap *bitmap;
1730         sector_t blocks = mddev->resync_max_sectors;
1731         struct file *file = mddev->bitmap_info.file;
1732         int err;
1733         struct kernfs_node *bm = NULL;
1734
1735         BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
1736
1737         BUG_ON(file && mddev->bitmap_info.offset);
1738
1739         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1740         if (!bitmap)
1741                 return ERR_PTR(-ENOMEM);
1742
1743         spin_lock_init(&bitmap->counts.lock);
1744         atomic_set(&bitmap->pending_writes, 0);
1745         init_waitqueue_head(&bitmap->write_wait);
1746         init_waitqueue_head(&bitmap->overflow_wait);
1747         init_waitqueue_head(&bitmap->behind_wait);
1748
1749         bitmap->mddev = mddev;
1750         bitmap->cluster_slot = slot;
1751
1752         if (mddev->kobj.sd)
1753                 bm = sysfs_get_dirent(mddev->kobj.sd, "bitmap");
1754         if (bm) {
1755                 bitmap->sysfs_can_clear = sysfs_get_dirent(bm, "can_clear");
1756                 sysfs_put(bm);
1757         } else
1758                 bitmap->sysfs_can_clear = NULL;
1759
1760         bitmap->storage.file = file;
1761         if (file) {
1762                 get_file(file);
1763                 /* As future accesses to this file will use bmap,
1764                  * and bypass the page cache, we must sync the file
1765                  * first.
1766                  */
1767                 vfs_fsync(file, 1);
1768         }
1769         /* read superblock from bitmap file (this sets mddev->bitmap_info.chunksize) */
1770         if (!mddev->bitmap_info.external) {
1771                 /*
1772                  * If 'MD_ARRAY_FIRST_USE' is set, then device-mapper is
1773                  * instructing us to create a new on-disk bitmap instance.
1774                  */
1775                 if (test_and_clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags))
1776                         err = bitmap_new_disk_sb(bitmap);
1777                 else
1778                         err = bitmap_read_sb(bitmap);
1779         } else {
1780                 err = 0;
1781                 if (mddev->bitmap_info.chunksize == 0 ||
1782                     mddev->bitmap_info.daemon_sleep == 0)
1783                         /* chunksize and time_base need to be
1784                          * set first. */
1785                         err = -EINVAL;
1786         }
1787         if (err)
1788                 goto error;
1789
1790         bitmap->daemon_lastrun = jiffies;
1791         err = bitmap_resize(bitmap, blocks, mddev->bitmap_info.chunksize, 1);
1792         if (err)
1793                 goto error;
1794
1795         printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
1796                bitmap->counts.pages, bmname(bitmap));
1797
1798         err = test_bit(BITMAP_WRITE_ERROR, &bitmap->flags) ? -EIO : 0;
1799         if (err)
1800                 goto error;
1801
1802         return bitmap;
1803  error:
1804         bitmap_free(bitmap);
1805         return ERR_PTR(err);
1806 }
1807
1808 int bitmap_load(struct mddev *mddev)
1809 {
1810         int err = 0;
1811         sector_t start = 0;
1812         sector_t sector = 0;
1813         struct bitmap *bitmap = mddev->bitmap;
1814
1815         if (!bitmap)
1816                 goto out;
1817
1818         /* Clear out old bitmap info first:  Either there is none, or we
1819          * are resuming after someone else has possibly changed things,
1820          * so we should forget old cached info.
1821          * All chunks should be clean, but some might need_sync.
1822          */
1823         while (sector < mddev->resync_max_sectors) {
1824                 sector_t blocks;
1825                 bitmap_start_sync(bitmap, sector, &blocks, 0);
1826                 sector += blocks;
1827         }
1828         bitmap_close_sync(bitmap);
1829
1830         if (mddev->degraded == 0
1831             || bitmap->events_cleared == mddev->events)
1832                 /* no need to keep dirty bits to optimise a
1833                  * re-add of a missing device */
1834                 start = mddev->recovery_cp;
1835
1836         mutex_lock(&mddev->bitmap_info.mutex);
1837         err = bitmap_init_from_disk(bitmap, start);
1838         mutex_unlock(&mddev->bitmap_info.mutex);
1839
1840         if (err)
1841                 goto out;
1842         clear_bit(BITMAP_STALE, &bitmap->flags);
1843
1844         /* Kick recovery in case any bits were set */
1845         set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
1846
1847         mddev->thread->timeout = mddev->bitmap_info.daemon_sleep;
1848         md_wakeup_thread(mddev->thread);
1849
1850         bitmap_update_sb(bitmap);
1851
1852         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
1853                 err = -EIO;
1854 out:
1855         return err;
1856 }
1857 EXPORT_SYMBOL_GPL(bitmap_load);
1858
1859 /* Loads the bitmap associated with slot and copies the resync information
1860  * to our bitmap
1861  */
1862 int bitmap_copy_from_slot(struct mddev *mddev, int slot,
1863                 sector_t *low, sector_t *high, bool clear_bits)
1864 {
1865         int rv = 0, i, j;
1866         sector_t block, lo = 0, hi = 0;
1867         struct bitmap_counts *counts;
1868         struct bitmap *bitmap = bitmap_create(mddev, slot);
1869
1870         if (IS_ERR(bitmap))
1871                 return PTR_ERR(bitmap);
1872
1873         rv = bitmap_init_from_disk(bitmap, 0);
1874         if (rv)
1875                 goto err;
1876
1877         counts = &bitmap->counts;
1878         for (j = 0; j < counts->chunks; j++) {
1879                 block = (sector_t)j << counts->chunkshift;
1880                 if (bitmap_file_test_bit(bitmap, block)) {
1881                         if (!lo)
1882                                 lo = block;
1883                         hi = block;
1884                         bitmap_file_clear_bit(bitmap, block);
1885                         bitmap_set_memory_bits(mddev->bitmap, block, 1);
1886                         bitmap_file_set_bit(mddev->bitmap, block);
1887                 }
1888         }
1889
1890         if (clear_bits) {
1891                 bitmap_update_sb(bitmap);
1892                 /* Setting this for the ev_page should be enough.
1893                  * And we do not require both write_all and PAGE_DIRT either
1894                  */
1895                 for (i = 0; i < bitmap->storage.file_pages; i++)
1896                         set_page_attr(bitmap, i, BITMAP_PAGE_DIRTY);
1897                 bitmap_write_all(bitmap);
1898                 bitmap_unplug(bitmap);
1899         }
1900         *low = lo;
1901         *high = hi;
1902 err:
1903         bitmap_free(bitmap);
1904         return rv;
1905 }
1906 EXPORT_SYMBOL_GPL(bitmap_copy_from_slot);
1907
1908
1909 void bitmap_status(struct seq_file *seq, struct bitmap *bitmap)
1910 {
1911         unsigned long chunk_kb;
1912         struct bitmap_counts *counts;
1913
1914         if (!bitmap)
1915                 return;
1916
1917         counts = &bitmap->counts;
1918
1919         chunk_kb = bitmap->mddev->bitmap_info.chunksize >> 10;
1920         seq_printf(seq, "bitmap: %lu/%lu pages [%luKB], "
1921                    "%lu%s chunk",
1922                    counts->pages - counts->missing_pages,
1923                    counts->pages,
1924                    (counts->pages - counts->missing_pages)
1925                    << (PAGE_SHIFT - 10),
1926                    chunk_kb ? chunk_kb : bitmap->mddev->bitmap_info.chunksize,
1927                    chunk_kb ? "KB" : "B");
1928         if (bitmap->storage.file) {
1929                 seq_printf(seq, ", file: ");
1930                 seq_file_path(seq, bitmap->storage.file, " \t\n");
1931         }
1932
1933         seq_printf(seq, "\n");
1934 }
1935
1936 int bitmap_resize(struct bitmap *bitmap, sector_t blocks,
1937                   int chunksize, int init)
1938 {
1939         /* If chunk_size is 0, choose an appropriate chunk size.
1940          * Then possibly allocate new storage space.
1941          * Then quiesce, copy bits, replace bitmap, and re-start
1942          *
1943          * This function is called both to set up the initial bitmap
1944          * and to resize the bitmap while the array is active.
1945          * If this happens as a result of the array being resized,
1946          * chunksize will be zero, and we need to choose a suitable
1947          * chunksize, otherwise we use what we are given.
1948          */
1949         struct bitmap_storage store;
1950         struct bitmap_counts old_counts;
1951         unsigned long chunks;
1952         sector_t block;
1953         sector_t old_blocks, new_blocks;
1954         int chunkshift;
1955         int ret = 0;
1956         long pages;
1957         struct bitmap_page *new_bp;
1958
1959         if (chunksize == 0) {
1960                 /* If there is enough space, leave the chunk size unchanged,
1961                  * else increase by factor of two until there is enough space.
1962                  */
1963                 long bytes;
1964                 long space = bitmap->mddev->bitmap_info.space;
1965
1966                 if (space == 0) {
1967                         /* We don't know how much space there is, so limit
1968                          * to current size - in sectors.
1969                          */
1970                         bytes = DIV_ROUND_UP(bitmap->counts.chunks, 8);
1971                         if (!bitmap->mddev->bitmap_info.external)
1972                                 bytes += sizeof(bitmap_super_t);
1973                         space = DIV_ROUND_UP(bytes, 512);
1974                         bitmap->mddev->bitmap_info.space = space;
1975                 }
1976                 chunkshift = bitmap->counts.chunkshift;
1977                 chunkshift--;
1978                 do {
1979                         /* 'chunkshift' is shift from block size to chunk size */
1980                         chunkshift++;
1981                         chunks = DIV_ROUND_UP_SECTOR_T(blocks, 1 << chunkshift);
1982                         bytes = DIV_ROUND_UP(chunks, 8);
1983                         if (!bitmap->mddev->bitmap_info.external)
1984                                 bytes += sizeof(bitmap_super_t);
1985                 } while (bytes > (space << 9));
1986         } else
1987                 chunkshift = ffz(~chunksize) - BITMAP_BLOCK_SHIFT;
1988
1989         chunks = DIV_ROUND_UP_SECTOR_T(blocks, 1 << chunkshift);
1990         memset(&store, 0, sizeof(store));
1991         if (bitmap->mddev->bitmap_info.offset || bitmap->mddev->bitmap_info.file)
1992                 ret = bitmap_storage_alloc(&store, chunks,
1993                                            !bitmap->mddev->bitmap_info.external,
1994                                            mddev_is_clustered(bitmap->mddev)
1995                                            ? bitmap->cluster_slot : 0);
1996         if (ret)
1997                 goto err;
1998
1999         pages = DIV_ROUND_UP(chunks, PAGE_COUNTER_RATIO);
2000
2001         new_bp = kzalloc(pages * sizeof(*new_bp), GFP_KERNEL);
2002         ret = -ENOMEM;
2003         if (!new_bp) {
2004                 bitmap_file_unmap(&store);
2005                 goto err;
2006         }
2007
2008         if (!init)
2009                 bitmap->mddev->pers->quiesce(bitmap->mddev, 1);
2010
2011         store.file = bitmap->storage.file;
2012         bitmap->storage.file = NULL;
2013
2014         if (store.sb_page && bitmap->storage.sb_page)
2015                 memcpy(page_address(store.sb_page),
2016                        page_address(bitmap->storage.sb_page),
2017                        sizeof(bitmap_super_t));
2018         bitmap_file_unmap(&bitmap->storage);
2019         bitmap->storage = store;
2020
2021         old_counts = bitmap->counts;
2022         bitmap->counts.bp = new_bp;
2023         bitmap->counts.pages = pages;
2024         bitmap->counts.missing_pages = pages;
2025         bitmap->counts.chunkshift = chunkshift;
2026         bitmap->counts.chunks = chunks;
2027         bitmap->mddev->bitmap_info.chunksize = 1 << (chunkshift +
2028                                                      BITMAP_BLOCK_SHIFT);
2029
2030         blocks = min(old_counts.chunks << old_counts.chunkshift,
2031                      chunks << chunkshift);
2032
2033         spin_lock_irq(&bitmap->counts.lock);
2034         for (block = 0; block < blocks; ) {
2035                 bitmap_counter_t *bmc_old, *bmc_new;
2036                 int set;
2037
2038                 bmc_old = bitmap_get_counter(&old_counts, block,
2039                                              &old_blocks, 0);
2040                 set = bmc_old && NEEDED(*bmc_old);
2041
2042                 if (set) {
2043                         bmc_new = bitmap_get_counter(&bitmap->counts, block,
2044                                                      &new_blocks, 1);
2045                         if (*bmc_new == 0) {
2046                                 /* need to set on-disk bits too. */
2047                                 sector_t end = block + new_blocks;
2048                                 sector_t start = block >> chunkshift;
2049                                 start <<= chunkshift;
2050                                 while (start < end) {
2051                                         bitmap_file_set_bit(bitmap, block);
2052                                         start += 1 << chunkshift;
2053                                 }
2054                                 *bmc_new = 2;
2055                                 bitmap_count_page(&bitmap->counts,
2056                                                   block, 1);
2057                                 bitmap_set_pending(&bitmap->counts,
2058                                                    block);
2059                         }
2060                         *bmc_new |= NEEDED_MASK;
2061                         if (new_blocks < old_blocks)
2062                                 old_blocks = new_blocks;
2063                 }
2064                 block += old_blocks;
2065         }
2066
2067         if (!init) {
2068                 int i;
2069                 while (block < (chunks << chunkshift)) {
2070                         bitmap_counter_t *bmc;
2071                         bmc = bitmap_get_counter(&bitmap->counts, block,
2072                                                  &new_blocks, 1);
2073                         if (bmc) {
2074                                 /* new space.  It needs to be resynced, so
2075                                  * we set NEEDED_MASK.
2076                                  */
2077                                 if (*bmc == 0) {
2078                                         *bmc = NEEDED_MASK | 2;
2079                                         bitmap_count_page(&bitmap->counts,
2080                                                           block, 1);
2081                                         bitmap_set_pending(&bitmap->counts,
2082                                                            block);
2083                                 }
2084                         }
2085                         block += new_blocks;
2086                 }
2087                 for (i = 0; i < bitmap->storage.file_pages; i++)
2088                         set_page_attr(bitmap, i, BITMAP_PAGE_DIRTY);
2089         }
2090         spin_unlock_irq(&bitmap->counts.lock);
2091
2092         if (!init) {
2093                 bitmap_unplug(bitmap);
2094                 bitmap->mddev->pers->quiesce(bitmap->mddev, 0);
2095         }
2096         ret = 0;
2097 err:
2098         return ret;
2099 }
2100 EXPORT_SYMBOL_GPL(bitmap_resize);
2101
2102 static ssize_t
2103 location_show(struct mddev *mddev, char *page)
2104 {
2105         ssize_t len;
2106         if (mddev->bitmap_info.file)
2107                 len = sprintf(page, "file");
2108         else if (mddev->bitmap_info.offset)
2109                 len = sprintf(page, "%+lld", (long long)mddev->bitmap_info.offset);
2110         else
2111                 len = sprintf(page, "none");
2112         len += sprintf(page+len, "\n");
2113         return len;
2114 }
2115
2116 static ssize_t
2117 location_store(struct mddev *mddev, const char *buf, size_t len)
2118 {
2119
2120         if (mddev->pers) {
2121                 if (!mddev->pers->quiesce)
2122                         return -EBUSY;
2123                 if (mddev->recovery || mddev->sync_thread)
2124                         return -EBUSY;
2125         }
2126
2127         if (mddev->bitmap || mddev->bitmap_info.file ||
2128             mddev->bitmap_info.offset) {
2129                 /* bitmap already configured.  Only option is to clear it */
2130                 if (strncmp(buf, "none", 4) != 0)
2131                         return -EBUSY;
2132                 if (mddev->pers) {
2133                         mddev->pers->quiesce(mddev, 1);
2134                         bitmap_destroy(mddev);
2135                         mddev->pers->quiesce(mddev, 0);
2136                 }
2137                 mddev->bitmap_info.offset = 0;
2138                 if (mddev->bitmap_info.file) {
2139                         struct file *f = mddev->bitmap_info.file;
2140                         mddev->bitmap_info.file = NULL;
2141                         fput(f);
2142                 }
2143         } else {
2144                 /* No bitmap, OK to set a location */
2145                 long long offset;
2146                 if (strncmp(buf, "none", 4) == 0)
2147                         /* nothing to be done */;
2148                 else if (strncmp(buf, "file:", 5) == 0) {
2149                         /* Not supported yet */
2150                         return -EINVAL;
2151                 } else {
2152                         int rv;
2153                         if (buf[0] == '+')
2154                                 rv = kstrtoll(buf+1, 10, &offset);
2155                         else
2156                                 rv = kstrtoll(buf, 10, &offset);
2157                         if (rv)
2158                                 return rv;
2159                         if (offset == 0)
2160                                 return -EINVAL;
2161                         if (mddev->bitmap_info.external == 0 &&
2162                             mddev->major_version == 0 &&
2163                             offset != mddev->bitmap_info.default_offset)
2164                                 return -EINVAL;
2165                         mddev->bitmap_info.offset = offset;
2166                         if (mddev->pers) {
2167                                 struct bitmap *bitmap;
2168                                 mddev->pers->quiesce(mddev, 1);
2169                                 bitmap = bitmap_create(mddev, -1);
2170                                 if (IS_ERR(bitmap))
2171                                         rv = PTR_ERR(bitmap);
2172                                 else {
2173                                         mddev->bitmap = bitmap;
2174                                         rv = bitmap_load(mddev);
2175                                         if (rv) {
2176                                                 bitmap_destroy(mddev);
2177                                                 mddev->bitmap_info.offset = 0;
2178                                         }
2179                                 }
2180                                 mddev->pers->quiesce(mddev, 0);
2181                                 if (rv)
2182                                         return rv;
2183                         }
2184                 }
2185         }
2186         if (!mddev->external) {
2187                 /* Ensure new bitmap info is stored in
2188                  * metadata promptly.
2189                  */
2190                 set_bit(MD_CHANGE_DEVS, &mddev->flags);
2191                 md_wakeup_thread(mddev->thread);
2192         }
2193         return len;
2194 }
2195
2196 static struct md_sysfs_entry bitmap_location =
2197 __ATTR(location, S_IRUGO|S_IWUSR, location_show, location_store);
2198
2199 /* 'bitmap/space' is the space available at 'location' for the
2200  * bitmap.  This allows the kernel to know when it is safe to
2201  * resize the bitmap to match a resized array.
2202  */
2203 static ssize_t
2204 space_show(struct mddev *mddev, char *page)
2205 {
2206         return sprintf(page, "%lu\n", mddev->bitmap_info.space);
2207 }
2208
2209 static ssize_t
2210 space_store(struct mddev *mddev, const char *buf, size_t len)
2211 {
2212         unsigned long sectors;
2213         int rv;
2214
2215         rv = kstrtoul(buf, 10, &sectors);
2216         if (rv)
2217                 return rv;
2218
2219         if (sectors == 0)
2220                 return -EINVAL;
2221
2222         if (mddev->bitmap &&
2223             sectors < (mddev->bitmap->storage.bytes + 511) >> 9)
2224                 return -EFBIG; /* Bitmap is too big for this small space */
2225
2226         /* could make sure it isn't too big, but that isn't really
2227          * needed - user-space should be careful.
2228          */
2229         mddev->bitmap_info.space = sectors;
2230         return len;
2231 }
2232
2233 static struct md_sysfs_entry bitmap_space =
2234 __ATTR(space, S_IRUGO|S_IWUSR, space_show, space_store);
2235
2236 static ssize_t
2237 timeout_show(struct mddev *mddev, char *page)
2238 {
2239         ssize_t len;
2240         unsigned long secs = mddev->bitmap_info.daemon_sleep / HZ;
2241         unsigned long jifs = mddev->bitmap_info.daemon_sleep % HZ;
2242
2243         len = sprintf(page, "%lu", secs);
2244         if (jifs)
2245                 len += sprintf(page+len, ".%03u", jiffies_to_msecs(jifs));
2246         len += sprintf(page+len, "\n");
2247         return len;
2248 }
2249
2250 static ssize_t
2251 timeout_store(struct mddev *mddev, const char *buf, size_t len)
2252 {
2253         /* timeout can be set at any time */
2254         unsigned long timeout;
2255         int rv = strict_strtoul_scaled(buf, &timeout, 4);
2256         if (rv)
2257                 return rv;
2258
2259         /* just to make sure we don't overflow... */
2260         if (timeout >= LONG_MAX / HZ)
2261                 return -EINVAL;
2262
2263         timeout = timeout * HZ / 10000;
2264
2265         if (timeout >= MAX_SCHEDULE_TIMEOUT)
2266                 timeout = MAX_SCHEDULE_TIMEOUT-1;
2267         if (timeout < 1)
2268                 timeout = 1;
2269         mddev->bitmap_info.daemon_sleep = timeout;
2270         if (mddev->thread) {
2271                 /* if thread->timeout is MAX_SCHEDULE_TIMEOUT, then
2272                  * the bitmap is all clean and we don't need to
2273                  * adjust the timeout right now
2274                  */
2275                 if (mddev->thread->timeout < MAX_SCHEDULE_TIMEOUT) {
2276                         mddev->thread->timeout = timeout;
2277                         md_wakeup_thread(mddev->thread);
2278                 }
2279         }
2280         return len;
2281 }
2282
2283 static struct md_sysfs_entry bitmap_timeout =
2284 __ATTR(time_base, S_IRUGO|S_IWUSR, timeout_show, timeout_store);
2285
2286 static ssize_t
2287 backlog_show(struct mddev *mddev, char *page)
2288 {
2289         return sprintf(page, "%lu\n", mddev->bitmap_info.max_write_behind);
2290 }
2291
2292 static ssize_t
2293 backlog_store(struct mddev *mddev, const char *buf, size_t len)
2294 {
2295         unsigned long backlog;
2296         int rv = kstrtoul(buf, 10, &backlog);
2297         if (rv)
2298                 return rv;
2299         if (backlog > COUNTER_MAX)
2300                 return -EINVAL;
2301         mddev->bitmap_info.max_write_behind = backlog;
2302         return len;
2303 }
2304
2305 static struct md_sysfs_entry bitmap_backlog =
2306 __ATTR(backlog, S_IRUGO|S_IWUSR, backlog_show, backlog_store);
2307
2308 static ssize_t
2309 chunksize_show(struct mddev *mddev, char *page)
2310 {
2311         return sprintf(page, "%lu\n", mddev->bitmap_info.chunksize);
2312 }
2313
2314 static ssize_t
2315 chunksize_store(struct mddev *mddev, const char *buf, size_t len)
2316 {
2317         /* Can only be changed when no bitmap is active */
2318         int rv;
2319         unsigned long csize;
2320         if (mddev->bitmap)
2321                 return -EBUSY;
2322         rv = kstrtoul(buf, 10, &csize);
2323         if (rv)
2324                 return rv;
2325         if (csize < 512 ||
2326             !is_power_of_2(csize))
2327                 return -EINVAL;
2328         mddev->bitmap_info.chunksize = csize;
2329         return len;
2330 }
2331
2332 static struct md_sysfs_entry bitmap_chunksize =
2333 __ATTR(chunksize, S_IRUGO|S_IWUSR, chunksize_show, chunksize_store);
2334
2335 static ssize_t metadata_show(struct mddev *mddev, char *page)
2336 {
2337         if (mddev_is_clustered(mddev))
2338                 return sprintf(page, "clustered\n");
2339         return sprintf(page, "%s\n", (mddev->bitmap_info.external
2340                                       ? "external" : "internal"));
2341 }
2342
2343 static ssize_t metadata_store(struct mddev *mddev, const char *buf, size_t len)
2344 {
2345         if (mddev->bitmap ||
2346             mddev->bitmap_info.file ||
2347             mddev->bitmap_info.offset)
2348                 return -EBUSY;
2349         if (strncmp(buf, "external", 8) == 0)
2350                 mddev->bitmap_info.external = 1;
2351         else if ((strncmp(buf, "internal", 8) == 0) ||
2352                         (strncmp(buf, "clustered", 9) == 0))
2353                 mddev->bitmap_info.external = 0;
2354         else
2355                 return -EINVAL;
2356         return len;
2357 }
2358
2359 static struct md_sysfs_entry bitmap_metadata =
2360 __ATTR(metadata, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
2361
2362 static ssize_t can_clear_show(struct mddev *mddev, char *page)
2363 {
2364         int len;
2365         spin_lock(&mddev->lock);
2366         if (mddev->bitmap)
2367                 len = sprintf(page, "%s\n", (mddev->bitmap->need_sync ?
2368                                              "false" : "true"));
2369         else
2370                 len = sprintf(page, "\n");
2371         spin_unlock(&mddev->lock);
2372         return len;
2373 }
2374
2375 static ssize_t can_clear_store(struct mddev *mddev, const char *buf, size_t len)
2376 {
2377         if (mddev->bitmap == NULL)
2378                 return -ENOENT;
2379         if (strncmp(buf, "false", 5) == 0)
2380                 mddev->bitmap->need_sync = 1;
2381         else if (strncmp(buf, "true", 4) == 0) {
2382                 if (mddev->degraded)
2383                         return -EBUSY;
2384                 mddev->bitmap->need_sync = 0;
2385         } else
2386                 return -EINVAL;
2387         return len;
2388 }
2389
2390 static struct md_sysfs_entry bitmap_can_clear =
2391 __ATTR(can_clear, S_IRUGO|S_IWUSR, can_clear_show, can_clear_store);
2392
2393 static ssize_t
2394 behind_writes_used_show(struct mddev *mddev, char *page)
2395 {
2396         ssize_t ret;
2397         spin_lock(&mddev->lock);
2398         if (mddev->bitmap == NULL)
2399                 ret = sprintf(page, "0\n");
2400         else
2401                 ret = sprintf(page, "%lu\n",
2402                               mddev->bitmap->behind_writes_used);
2403         spin_unlock(&mddev->lock);
2404         return ret;
2405 }
2406
2407 static ssize_t
2408 behind_writes_used_reset(struct mddev *mddev, const char *buf, size_t len)
2409 {
2410         if (mddev->bitmap)
2411                 mddev->bitmap->behind_writes_used = 0;
2412         return len;
2413 }
2414
2415 static struct md_sysfs_entry max_backlog_used =
2416 __ATTR(max_backlog_used, S_IRUGO | S_IWUSR,
2417        behind_writes_used_show, behind_writes_used_reset);
2418
2419 static struct attribute *md_bitmap_attrs[] = {
2420         &bitmap_location.attr,
2421         &bitmap_space.attr,
2422         &bitmap_timeout.attr,
2423         &bitmap_backlog.attr,
2424         &bitmap_chunksize.attr,
2425         &bitmap_metadata.attr,
2426         &bitmap_can_clear.attr,
2427         &max_backlog_used.attr,
2428         NULL
2429 };
2430 struct attribute_group md_bitmap_group = {
2431         .name = "bitmap",
2432         .attrs = md_bitmap_attrs,
2433 };
2434