kernel/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         int node_offset = 0;
 214
 215         if (mddev_is_clustered(bitmap->mddev))
 216                 node_offset = bitmap->cluster_slot * store->file_pages;
 217
 218         while ((rdev = next_active_rdev(rdev, mddev)) != NULL) {
 219                 int size = PAGE_SIZE;
 220                 loff_t offset = mddev->bitmap_info.offset;
 221
 222                 bdev = (rdev->meta_bdev) ? rdev->meta_bdev : rdev->bdev;
 223
 224                 if (page->index == store->file_pages-1) {
 225                         int last_page_size = store->bytes & (PAGE_SIZE-1);
 226                         if (last_page_size == 0)
 227                                 last_page_size = PAGE_SIZE;
 228                         size = roundup(last_page_size,
 229                                        bdev_logical_block_size(bdev));
 230                 }
 231                 /* Just make sure we aren't corrupting data or
 232                  * metadata
 233                  */
 234                 if (mddev->external) {
 235                         /* Bitmap could be anywhere. */
 236                         if (rdev->sb_start + offset + (page->index
 237                                                        * (PAGE_SIZE/512))
 238                             > rdev->data_offset
 239                             &&
 240                             rdev->sb_start + offset
 241                             < (rdev->data_offset + mddev->dev_sectors
 242                              + (PAGE_SIZE/512)))
 243                                 goto bad_alignment;
 244                 } else if (offset < 0) {
 245                         /* DATA  BITMAP METADATA  */
 246                         if (offset
 247                             + (long)(page->index * (PAGE_SIZE/512))
 248                             + size/512 > 0)
 249                                 /* bitmap runs in to metadata */
 250                                 goto bad_alignment;
 251                         if (rdev->data_offset + mddev->dev_sectors
 252                             > rdev->sb_start + offset)
 253                                 /* data runs in to bitmap */
 254                                 goto bad_alignment;
 255                 } else if (rdev->sb_start < rdev->data_offset) {
 256                         /* METADATA BITMAP DATA */
 257                         if (rdev->sb_start
 258                             + offset
 259                             + page->index*(PAGE_SIZE/512) + size/512
 260                             > rdev->data_offset)
 261                                 /* bitmap runs in to data */
 262                                 goto bad_alignment;
 263                 } else {
 264                         /* DATA METADATA BITMAP - no problems */
 265                 }
 266                 md_super_write(mddev, rdev,
 267                                rdev->sb_start + offset
 268                                + page->index * (PAGE_SIZE/512),
 269                                size,
 270                                page);
 271         }
 272
 273         if (wait)
 274                 md_super_wait(mddev);
 275         return 0;
 276
 277  bad_alignment:
 278         return -EINVAL;
 279 }
 280
 281 static void bitmap_file_kick(struct bitmap *bitmap);
 282 /*
 283  * write out a page to a file
 284  */
 285 static void write_page(struct bitmap *bitmap, struct page *page, int wait)
 286 {
 287         struct buffer_head *bh;
 288
 289         if (bitmap->storage.file == NULL) {
 290                 switch (write_sb_page(bitmap, page, wait)) {
 291                 case -EINVAL:
 292                         set_bit(BITMAP_WRITE_ERROR, &bitmap->flags);
 293                 }
 294         } else {
 295
 296                 bh = page_buffers(page);
 297
 298                 while (bh && bh->b_blocknr) {
 299                         atomic_inc(&bitmap->pending_writes);
 300                         set_buffer_locked(bh);
 301                         set_buffer_mapped(bh);
 302                         submit_bh(WRITE | REQ_SYNC, bh);
 303                         bh = bh->b_this_page;
 304                 }
 305
 306                 if (wait)
 307                         wait_event(bitmap->write_wait,
 308                                    atomic_read(&bitmap->pending_writes)==0);
 309         }
 310         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
 311                 bitmap_file_kick(bitmap);
 312 }
 313
 314 static void end_bitmap_write(struct buffer_head *bh, int uptodate)
 315 {
 316         struct bitmap *bitmap = bh->b_private;
 317
 318         if (!uptodate)
 319                 set_bit(BITMAP_WRITE_ERROR, &bitmap->flags);
 320         if (atomic_dec_and_test(&bitmap->pending_writes))
 321                 wake_up(&bitmap->write_wait);
 322 }
 323
 324 /* copied from buffer.c */
 325 static void
 326 __clear_page_buffers(struct page *page)
 327 {
 328         ClearPagePrivate(page);
 329         set_page_private(page, 0);
 330         page_cache_release(page);
 331 }
 332 static void free_buffers(struct page *page)
 333 {
 334         struct buffer_head *bh;
 335
 336         if (!PagePrivate(page))
 337                 return;
 338
 339         bh = page_buffers(page);
 340         while (bh) {
 341                 struct buffer_head *next = bh->b_this_page;
 342                 free_buffer_head(bh);
 343                 bh = next;
 344         }
 345         __clear_page_buffers(page);
 346         put_page(page);
 347 }
 348
 349 /* read a page from a file.
 350  * We both read the page, and attach buffers to the page to record the
 351  * address of each block (using bmap).  These addresses will be used
 352  * to write the block later, completely bypassing the filesystem.
 353  * This usage is similar to how swap files are handled, and allows us
 354  * to write to a file with no concerns of memory allocation failing.
 355  */
 356 static int read_page(struct file *file, unsigned long index,
 357                      struct bitmap *bitmap,
 358                      unsigned long count,
 359                      struct page *page)
 360 {
 361         int ret = 0;
 362         struct inode *inode = file_inode(file);
 363         struct buffer_head *bh;
 364         sector_t block;
 365
 366         pr_debug("read bitmap file (%dB @ %llu)\n", (int)PAGE_SIZE,
 367                  (unsigned long long)index << PAGE_SHIFT);
 368
 369         bh = alloc_page_buffers(page, 1<<inode->i_blkbits, 0);
 370         if (!bh) {
 371                 ret = -ENOMEM;
 372                 goto out;
 373         }
 374         attach_page_buffers(page, bh);
 375         block = index << (PAGE_SHIFT - inode->i_blkbits);
 376         while (bh) {
 377                 if (count == 0)
 378                         bh->b_blocknr = 0;
 379                 else {
 380                         bh->b_blocknr = bmap(inode, block);
 381                         if (bh->b_blocknr == 0) {
 382                                 /* Cannot use this file! */
 383                                 ret = -EINVAL;
 384                                 goto out;
 385                         }
 386                         bh->b_bdev = inode->i_sb->s_bdev;
 387                         if (count < (1<<inode->i_blkbits))
 388                                 count = 0;
 389                         else
 390                                 count -= (1<<inode->i_blkbits);
 391
 392                         bh->b_end_io = end_bitmap_write;
 393                         bh->b_private = bitmap;
 394                         atomic_inc(&bitmap->pending_writes);
 395                         set_buffer_locked(bh);
 396                         set_buffer_mapped(bh);
 397                         submit_bh(READ, bh);
 398                 }
 399                 block++;
 400                 bh = bh->b_this_page;
 401         }
 402         page->index = index;
 403
 404         wait_event(bitmap->write_wait,
 405                    atomic_read(&bitmap->pending_writes)==0);
 406         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
 407                 ret = -EIO;
 408 out:
 409         if (ret)
 410                 printk(KERN_ALERT "md: bitmap read error: (%dB @ %llu): %d\n",
 411                         (int)PAGE_SIZE,
 412                         (unsigned long long)index << PAGE_SHIFT,
 413                         ret);
 414         return ret;
 415 }
 416
 417 /*
 418  * bitmap file superblock operations
 419  */
 420
 421 /* update the event counter and sync the superblock to disk */
 422 void bitmap_update_sb(struct bitmap *bitmap)
 423 {
 424         bitmap_super_t *sb;
 425
 426         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
 427                 return;
 428         if (bitmap->mddev->bitmap_info.external)
 429                 return;
 430         if (!bitmap->storage.sb_page) /* no superblock */
 431                 return;
 432         sb = kmap_atomic(bitmap->storage.sb_page);
 433         sb->events = cpu_to_le64(bitmap->mddev->events);
 434         if (bitmap->mddev->events < bitmap->events_cleared)
 435                 /* rocking back to read-only */
 436                 bitmap->events_cleared = bitmap->mddev->events;
 437         sb->events_cleared = cpu_to_le64(bitmap->events_cleared);
 438         sb->state = cpu_to_le32(bitmap->flags);
 439         /* Just in case these have been changed via sysfs: */
 440         sb->daemon_sleep = cpu_to_le32(bitmap->mddev->bitmap_info.daemon_sleep/HZ);
 441         sb->write_behind = cpu_to_le32(bitmap->mddev->bitmap_info.max_write_behind);
 442         /* This might have been changed by a reshape */
 443         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 444         sb->chunksize = cpu_to_le32(bitmap->mddev->bitmap_info.chunksize);
 445         sb->nodes = cpu_to_le32(bitmap->mddev->bitmap_info.nodes);
 446         sb->sectors_reserved = cpu_to_le32(bitmap->mddev->
 447                                            bitmap_info.space);
 448         kunmap_atomic(sb);
 449         write_page(bitmap, bitmap->storage.sb_page, 1);
 450 }
 451
 452 /* print out the bitmap file superblock */
 453 void bitmap_print_sb(struct bitmap *bitmap)
 454 {
 455         bitmap_super_t *sb;
 456
 457         if (!bitmap || !bitmap->storage.sb_page)
 458                 return;
 459         sb = kmap_atomic(bitmap->storage.sb_page);
 460         printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
 461         printk(KERN_DEBUG "         magic: %08x\n", le32_to_cpu(sb->magic));
 462         printk(KERN_DEBUG "       version: %d\n", le32_to_cpu(sb->version));
 463         printk(KERN_DEBUG "          uuid: %08x.%08x.%08x.%08x\n",
 464                                         *(__u32 *)(sb->uuid+0),
 465                                         *(__u32 *)(sb->uuid+4),
 466                                         *(__u32 *)(sb->uuid+8),
 467                                         *(__u32 *)(sb->uuid+12));
 468         printk(KERN_DEBUG "        events: %llu\n",
 469                         (unsigned long long) le64_to_cpu(sb->events));
 470         printk(KERN_DEBUG "events cleared: %llu\n",
 471                         (unsigned long long) le64_to_cpu(sb->events_cleared));
 472         printk(KERN_DEBUG "         state: %08x\n", le32_to_cpu(sb->state));
 473         printk(KERN_DEBUG "     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
 474         printk(KERN_DEBUG "  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
 475         printk(KERN_DEBUG "     sync size: %llu KB\n",
 476                         (unsigned long long)le64_to_cpu(sb->sync_size)/2);
 477         printk(KERN_DEBUG "max write behind: %d\n", le32_to_cpu(sb->write_behind));
 478         kunmap_atomic(sb);
 479 }
 480
 481 /*
 482  * bitmap_new_disk_sb
 483  * @bitmap
 484  *
 485  * This function is somewhat the reverse of bitmap_read_sb.  bitmap_read_sb
 486  * reads and verifies the on-disk bitmap superblock and populates bitmap_info.
 487  * This function verifies 'bitmap_info' and populates the on-disk bitmap
 488  * structure, which is to be written to disk.
 489  *
 490  * Returns: 0 on success, -Exxx on error
 491  */
 492 static int bitmap_new_disk_sb(struct bitmap *bitmap)
 493 {
 494         bitmap_super_t *sb;
 495         unsigned long chunksize, daemon_sleep, write_behind;
 496
 497         bitmap->storage.sb_page = alloc_page(GFP_KERNEL | __GFP_ZERO);
 498         if (bitmap->storage.sb_page == NULL)
 499                 return -ENOMEM;
 500         bitmap->storage.sb_page->index = 0;
 501
 502         sb = kmap_atomic(bitmap->storage.sb_page);
 503
 504         sb->magic = cpu_to_le32(BITMAP_MAGIC);
 505         sb->version = cpu_to_le32(BITMAP_MAJOR_HI);
 506
 507         chunksize = bitmap->mddev->bitmap_info.chunksize;
 508         BUG_ON(!chunksize);
 509         if (!is_power_of_2(chunksize)) {
 510                 kunmap_atomic(sb);
 511                 printk(KERN_ERR "bitmap chunksize not a power of 2\n");
 512                 return -EINVAL;
 513         }
 514         sb->chunksize = cpu_to_le32(chunksize);
 515
 516         daemon_sleep = bitmap->mddev->bitmap_info.daemon_sleep;
 517         if (!daemon_sleep ||
 518             (daemon_sleep < 1) || (daemon_sleep > MAX_SCHEDULE_TIMEOUT)) {
 519                 printk(KERN_INFO "Choosing daemon_sleep default (5 sec)\n");
 520                 daemon_sleep = 5 * HZ;
 521         }
 522         sb->daemon_sleep = cpu_to_le32(daemon_sleep);
 523         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 524
 525         /*
 526          * FIXME: write_behind for RAID1.  If not specified, what
 527          * is a good choice?  We choose COUNTER_MAX / 2 arbitrarily.
 528          */
 529         write_behind = bitmap->mddev->bitmap_info.max_write_behind;
 530         if (write_behind > COUNTER_MAX)
 531                 write_behind = COUNTER_MAX / 2;
 532         sb->write_behind = cpu_to_le32(write_behind);
 533         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 534
 535         /* keep the array size field of the bitmap superblock up to date */
 536         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 537
 538         memcpy(sb->uuid, bitmap->mddev->uuid, 16);
 539
 540         set_bit(BITMAP_STALE, &bitmap->flags);
 541         sb->state = cpu_to_le32(bitmap->flags);
 542         bitmap->events_cleared = bitmap->mddev->events;
 543         sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
 544         bitmap->mddev->bitmap_info.nodes = 0;
 545
 546         kunmap_atomic(sb);
 547
 548         return 0;
 549 }
 550
 551 /* read the superblock from the bitmap file and initialize some bitmap fields */
 552 static int bitmap_read_sb(struct bitmap *bitmap)
 553 {
 554         char *reason = NULL;
 555         bitmap_super_t *sb;
 556         unsigned long chunksize, daemon_sleep, write_behind;
 557         unsigned long long events;
 558         int nodes = 0;
 559         unsigned long sectors_reserved = 0;
 560         int err = -EINVAL;
 561         struct page *sb_page;
 562         loff_t offset = bitmap->mddev->bitmap_info.offset;
 563
 564         if (!bitmap->storage.file && !bitmap->mddev->bitmap_info.offset) {
 565                 chunksize = 128 * 1024 * 1024;
 566                 daemon_sleep = 5 * HZ;
 567                 write_behind = 0;
 568                 set_bit(BITMAP_STALE, &bitmap->flags);
 569                 err = 0;
 570                 goto out_no_sb;
 571         }
 572         /* page 0 is the superblock, read it... */
 573         sb_page = alloc_page(GFP_KERNEL);
 574         if (!sb_page)
 575                 return -ENOMEM;
 576         bitmap->storage.sb_page = sb_page;
 577
 578 re_read:
 579         /* If cluster_slot is set, the cluster is setup */
 580         if (bitmap->cluster_slot >= 0) {
 581                 sector_t bm_blocks = bitmap->mddev->resync_max_sectors;
 582
 583                 sector_div(bm_blocks,
 584                            bitmap->mddev->bitmap_info.chunksize >> 9);
 585                 /* bits to bytes */
 586                 bm_blocks = ((bm_blocks+7) >> 3) + sizeof(bitmap_super_t);
 587                 /* to 4k blocks */
 588                 bm_blocks = DIV_ROUND_UP_SECTOR_T(bm_blocks, 4096);
 589                 offset = bitmap->mddev->bitmap_info.offset + (bitmap->cluster_slot * (bm_blocks << 3));
 590                 pr_info("%s:%d bm slot: %d offset: %llu\n", __func__, __LINE__,
 591                         bitmap->cluster_slot, offset);
 592         }
 593
 594         if (bitmap->storage.file) {
 595                 loff_t isize = i_size_read(bitmap->storage.file->f_mapping->host);
 596                 int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
 597
 598                 err = read_page(bitmap->storage.file, 0,
 599                                 bitmap, bytes, sb_page);
 600         } else {
 601                 err = read_sb_page(bitmap->mddev,
 602                                    offset,
 603                                    sb_page,
 604                                    0, sizeof(bitmap_super_t));
 605         }
 606         if (err)
 607                 return err;
 608
 609         err = -EINVAL;
 610         sb = kmap_atomic(sb_page);
 611
 612         chunksize = le32_to_cpu(sb->chunksize);
 613         daemon_sleep = le32_to_cpu(sb->daemon_sleep) * HZ;
 614         write_behind = le32_to_cpu(sb->write_behind);
 615         sectors_reserved = le32_to_cpu(sb->sectors_reserved);
 616         /* Setup nodes/clustername only if bitmap version is
 617          * cluster-compatible
 618          */
 619         if (sb->version == cpu_to_le32(BITMAP_MAJOR_CLUSTERED)) {
 620                 nodes = le32_to_cpu(sb->nodes);
 621                 strlcpy(bitmap->mddev->bitmap_info.cluster_name,
 622                                 sb->cluster_name, 64);
 623         }
 624
 625         /* verify that the bitmap-specific fields are valid */
 626         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
 627                 reason = "bad magic";
 628         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
 629                  le32_to_cpu(sb->version) > BITMAP_MAJOR_CLUSTERED)
 630                 reason = "unrecognized superblock version";
 631         else if (chunksize < 512)
 632                 reason = "bitmap chunksize too small";
 633         else if (!is_power_of_2(chunksize))
 634                 reason = "bitmap chunksize not a power of 2";
 635         else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT)
 636                 reason = "daemon sleep period out of range";
 637         else if (write_behind > COUNTER_MAX)
 638                 reason = "write-behind limit out of range (0 - 16383)";
 639         if (reason) {
 640                 printk(KERN_INFO "%s: invalid bitmap file superblock: %s\n",
 641                         bmname(bitmap), reason);
 642                 goto out;
 643         }
 644
 645         /* keep the array size field of the bitmap superblock up to date */
 646         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 647
 648         if (bitmap->mddev->persistent) {
 649                 /*
 650                  * We have a persistent array superblock, so compare the
 651                  * bitmap's UUID and event counter to the mddev's
 652                  */
 653                 if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
 654                         printk(KERN_INFO
 655                                "%s: bitmap superblock UUID mismatch\n",
 656                                bmname(bitmap));
 657                         goto out;
 658                 }
 659                 events = le64_to_cpu(sb->events);
 660                 if (!nodes && (events < bitmap->mddev->events)) {
 661                         printk(KERN_INFO
 662                                "%s: bitmap file is out of date (%llu < %llu) "
 663                                "-- forcing full recovery\n",
 664                                bmname(bitmap), events,
 665                                (unsigned long long) bitmap->mddev->events);
 666                         set_bit(BITMAP_STALE, &bitmap->flags);
 667                 }
 668         }
 669
 670         /* assign fields using values from superblock */
 671         bitmap->flags |= le32_to_cpu(sb->state);
 672         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
 673                 set_bit(BITMAP_HOSTENDIAN, &bitmap->flags);
 674         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
 675         strlcpy(bitmap->mddev->bitmap_info.cluster_name, sb->cluster_name, 64);
 676         err = 0;
 677
 678 out:
 679         kunmap_atomic(sb);
 680         /* Assiging chunksize is required for "re_read" */
 681         bitmap->mddev->bitmap_info.chunksize = chunksize;
 682         if (err == 0 && nodes && (bitmap->cluster_slot < 0)) {
 683                 err = md_setup_cluster(bitmap->mddev, nodes);
 684                 if (err) {
 685                         pr_err("%s: Could not setup cluster service (%d)\n",
 686                                         bmname(bitmap), err);
 687                         goto out_no_sb;
 688                 }
 689                 bitmap->cluster_slot = md_cluster_ops->slot_number(bitmap->mddev);
 690                 goto re_read;
 691         }
 692
 693
 694 out_no_sb:
 695         if (test_bit(BITMAP_STALE, &bitmap->flags))
 696                 bitmap->events_cleared = bitmap->mddev->events;
 697         bitmap->mddev->bitmap_info.chunksize = chunksize;
 698         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 699         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 700         bitmap->mddev->bitmap_info.nodes = nodes;
 701         if (bitmap->mddev->bitmap_info.space == 0 ||
 702             bitmap->mddev->bitmap_info.space > sectors_reserved)
 703                 bitmap->mddev->bitmap_info.space = sectors_reserved;
 704         if (err) {
 705                 bitmap_print_sb(bitmap);
 706                 if (bitmap->cluster_slot < 0)
 707                         md_cluster_stop(bitmap->mddev);
 708         }
 709         return err;
 710 }
 711
 712 /*
 713  * general bitmap file operations
 714  */
 715
 716 /*
 717  * on-disk bitmap:
 718  *
 719  * Use one bit per "chunk" (block set). We do the disk I/O on the bitmap
 720  * file a page at a time. There's a superblock at the start of the file.
 721  */
 722 /* calculate the index of the page that contains this bit */
 723 static inline unsigned long file_page_index(struct bitmap_storage *store,
 724                                             unsigned long chunk)
 725 {
 726         if (store->sb_page)
 727                 chunk += sizeof(bitmap_super_t) << 3;
 728         return chunk >> PAGE_BIT_SHIFT;
 729 }
 730
 731 /* calculate the (bit) offset of this bit within a page */
 732 static inline unsigned long file_page_offset(struct bitmap_storage *store,
 733                                              unsigned long chunk)
 734 {
 735         if (store->sb_page)
 736                 chunk += sizeof(bitmap_super_t) << 3;
 737         return chunk & (PAGE_BITS - 1);
 738 }
 739
 740 /*
 741  * return a pointer to the page in the filemap that contains the given bit
 742  *
 743  */
 744 static inline struct page *filemap_get_page(struct bitmap_storage *store,
 745                                             unsigned long chunk)
 746 {
 747         if (file_page_index(store, chunk) >= store->file_pages)
 748                 return NULL;
 749         return store->filemap[file_page_index(store, chunk)];
 750 }
 751
 752 static int bitmap_storage_alloc(struct bitmap_storage *store,
 753                                 unsigned long chunks, int with_super,
 754                                 int slot_number)
 755 {
 756         int pnum, offset = 0;
 757         unsigned long num_pages;
 758         unsigned long bytes;
 759
 760         bytes = DIV_ROUND_UP(chunks, 8);
 761         if (with_super)
 762                 bytes += sizeof(bitmap_super_t);
 763
 764         num_pages = DIV_ROUND_UP(bytes, PAGE_SIZE);
 765         offset = slot_number * (num_pages - 1);
 766
 767         store->filemap = kmalloc(sizeof(struct page *)
 768                                  * num_pages, GFP_KERNEL);
 769         if (!store->filemap)
 770                 return -ENOMEM;
 771
 772         if (with_super && !store->sb_page) {
 773                 store->sb_page = alloc_page(GFP_KERNEL|__GFP_ZERO);
 774                 if (store->sb_page == NULL)
 775                         return -ENOMEM;
 776         }
 777
 778         pnum = 0;
 779         if (store->sb_page) {
 780                 store->filemap[0] = store->sb_page;
 781                 pnum = 1;
 782                 store->sb_page->index = offset;
 783         }
 784
 785         for ( ; pnum < num_pages; pnum++) {
 786                 store->filemap[pnum] = alloc_page(GFP_KERNEL|__GFP_ZERO);
 787                 if (!store->filemap[pnum]) {
 788                         store->file_pages = pnum;
 789                         return -ENOMEM;
 790                 }
 791                 store->filemap[pnum]->index = pnum + offset;
 792         }
 793         store->file_pages = pnum;
 794
 795         /* We need 4 bits per page, rounded up to a multiple
 796          * of sizeof(unsigned long) */
 797         store->filemap_attr = kzalloc(
 798                 roundup(DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
 799                 GFP_KERNEL);
 800         if (!store->filemap_attr)
 801                 return -ENOMEM;
 802
 803         store->bytes = bytes;
 804
 805         return 0;
 806 }
 807
 808 static void bitmap_file_unmap(struct bitmap_storage *store)
 809 {
 810         struct page **map, *sb_page;
 811         int pages;
 812         struct file *file;
 813
 814         file = store->file;
 815         map = store->filemap;
 816         pages = store->file_pages;
 817         sb_page = store->sb_page;
 818
 819         while (pages--)
 820                 if (map[pages] != sb_page) /* 0 is sb_page, release it below */
 821                         free_buffers(map[pages]);
 822         kfree(map);
 823         kfree(store->filemap_attr);
 824
 825         if (sb_page)
 826                 free_buffers(sb_page);
 827
 828         if (file) {
 829                 struct inode *inode = file_inode(file);
 830                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
 831                 fput(file);
 832         }
 833 }
 834
 835 /*
 836  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
 837  * then it is no longer reliable, so we stop using it and we mark the file
 838  * as failed in the superblock
 839  */
 840 static void bitmap_file_kick(struct bitmap *bitmap)
 841 {
 842         char *path, *ptr = NULL;
 843
 844         if (!test_and_set_bit(BITMAP_STALE, &bitmap->flags)) {
 845                 bitmap_update_sb(bitmap);
 846
 847                 if (bitmap->storage.file) {
 848                         path = kmalloc(PAGE_SIZE, GFP_KERNEL);
 849                         if (path)
 850                                 ptr = file_path(bitmap->storage.file,
 851                                              path, PAGE_SIZE);
 852
 853                         printk(KERN_ALERT
 854                               "%s: kicking failed bitmap file %s from array!\n",
 855                               bmname(bitmap), IS_ERR(ptr) ? "" : ptr);
 856
 857                         kfree(path);
 858                 } else
 859                         printk(KERN_ALERT
 860                                "%s: disabling internal bitmap due to errors\n",
 861                                bmname(bitmap));
 862         }
 863 }
 864
 865 enum bitmap_page_attr {
 866         BITMAP_PAGE_DIRTY = 0,     /* there are set bits that need to be synced */
 867         BITMAP_PAGE_PENDING = 1,   /* there are bits that are being cleaned.
 868                                     * i.e. counter is 1 or 2. */
 869         BITMAP_PAGE_NEEDWRITE = 2, /* there are cleared bits that need to be synced */
 870 };
 871
 872 static inline void set_page_attr(struct bitmap *bitmap, int pnum,
 873                                  enum bitmap_page_attr attr)
 874 {
 875         set_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 876 }
 877
 878 static inline void clear_page_attr(struct bitmap *bitmap, int pnum,
 879                                    enum bitmap_page_attr attr)
 880 {
 881         clear_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 882 }
 883
 884 static inline int test_page_attr(struct bitmap *bitmap, int pnum,
 885                                  enum bitmap_page_attr attr)
 886 {
 887         return test_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 888 }
 889
 890 static inline int test_and_clear_page_attr(struct bitmap *bitmap, int pnum,
 891                                            enum bitmap_page_attr attr)
 892 {
 893         return test_and_clear_bit((pnum<<2) + attr,
 894                                   bitmap->storage.filemap_attr);
 895 }
 896 /*
 897  * bitmap_file_set_bit -- called before performing a write to the md device
 898  * to set (and eventually sync) a particular bit in the bitmap file
 899  *
 900  * we set the bit immediately, then we record the page number so that
 901  * when an unplug occurs, we can flush the dirty pages out to disk
 902  */
 903 static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 904 {
 905         unsigned long bit;
 906         struct page *page;
 907         void *kaddr;
 908         unsigned long chunk = block >> bitmap->counts.chunkshift;
 909
 910         page = filemap_get_page(&bitmap->storage, chunk);
 911         if (!page)
 912                 return;
 913         bit = file_page_offset(&bitmap->storage, chunk);
 914
 915         /* set the bit */
 916         kaddr = kmap_atomic(page);
 917         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
 918                 set_bit(bit, kaddr);
 919         else
 920                 set_bit_le(bit, kaddr);
 921         kunmap_atomic(kaddr);
 922         pr_debug("set file bit %lu page %lu\n", bit, page->index);
 923         /* record page number so it gets flushed to disk when unplug occurs */
 924         set_page_attr(bitmap, page->index, BITMAP_PAGE_DIRTY);
 925 }
 926
 927 static void bitmap_file_clear_bit(struct bitmap *bitmap, sector_t block)
 928 {
 929         unsigned long bit;
 930         struct page *page;
 931         void *paddr;
 932         unsigned long chunk = block >> bitmap->counts.chunkshift;
 933
 934         page = filemap_get_page(&bitmap->storage, chunk);
 935         if (!page)
 936                 return;
 937         bit = file_page_offset(&bitmap->storage, chunk);
 938         paddr = kmap_atomic(page);
 939         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
 940                 clear_bit(bit, paddr);
 941         else
 942                 clear_bit_le(bit, paddr);
 943         kunmap_atomic(paddr);
 944         if (!test_page_attr(bitmap, page->index, BITMAP_PAGE_NEEDWRITE)) {
 945                 set_page_attr(bitmap, page->index, BITMAP_PAGE_PENDING);
 946                 bitmap->allclean = 0;
 947         }
 948 }
 949
 950 static int bitmap_file_test_bit(struct bitmap *bitmap, sector_t block)
 951 {
 952         unsigned long bit;
 953         struct page *page;
 954         void *paddr;
 955         unsigned long chunk = block >> bitmap->counts.chunkshift;
 956         int set = 0;
 957
 958         page = filemap_get_page(&bitmap->storage, chunk);
 959         if (!page)
 960                 return -EINVAL;
 961         bit = file_page_offset(&bitmap->storage, chunk);
 962         paddr = kmap_atomic(page);
 963         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
 964                 set = test_bit(bit, paddr);
 965         else
 966                 set = test_bit_le(bit, paddr);
 967         kunmap_atomic(paddr);
 968         return set;
 969 }
 970
 971
 972 /* this gets called when the md device is ready to unplug its underlying
 973  * (slave) device queues -- before we let any writes go down, we need to
 974  * sync the dirty pages of the bitmap file to disk */
 975 void bitmap_unplug(struct bitmap *bitmap)
 976 {
 977         unsigned long i;
 978         int dirty, need_write;
 979
 980         if (!bitmap || !bitmap->storage.filemap ||
 981             test_bit(BITMAP_STALE, &bitmap->flags))
 982                 return;
 983
 984         /* look at each page to see if there are any set bits that need to be
 985          * flushed out to disk */
 986         for (i = 0; i < bitmap->storage.file_pages; i++) {
 987                 if (!bitmap->storage.filemap)
 988                         return;
 989                 dirty = test_and_clear_page_attr(bitmap, i, BITMAP_PAGE_DIRTY);
 990                 need_write = test_and_clear_page_attr(bitmap, i,
 991                                                       BITMAP_PAGE_NEEDWRITE);
 992                 if (dirty || need_write) {
 993                         clear_page_attr(bitmap, i, BITMAP_PAGE_PENDING);
 994                         write_page(bitmap, bitmap->storage.filemap[i], 0);
 995                 }
 996         }
 997         if (bitmap->storage.file)
 998                 wait_event(bitmap->write_wait,
 999                            atomic_read(&bitmap->pending_writes)==0);
1000         else
1001                 md_super_wait(bitmap->mddev);
1002
1003         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
1004                 bitmap_file_kick(bitmap);
1005 }
1006 EXPORT_SYMBOL(bitmap_unplug);
1007
1008 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
1009 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
1010  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
1011  * memory mapping of the bitmap file
1012  * Special cases:
1013  *   if there's no bitmap file, or if the bitmap file had been
1014  *   previously kicked from the array, we mark all the bits as
1015  *   1's in order to cause a full resync.
1016  *
1017  * We ignore all bits for sectors that end earlier than 'start'.
1018  * This is used when reading an out-of-date bitmap...
1019  */
1020 static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
1021 {
1022         unsigned long i, chunks, index, oldindex, bit, node_offset = 0;
1023         struct page *page = NULL;
1024         unsigned long bit_cnt = 0;
1025         struct file *file;
1026         unsigned long offset;
1027         int outofdate;
1028         int ret = -ENOSPC;
1029         void *paddr;
1030         struct bitmap_storage *store = &bitmap->storage;
1031
1032         chunks = bitmap->counts.chunks;
1033         file = store->file;
1034
1035         if (!file && !bitmap->mddev->bitmap_info.offset) {
1036                 /* No permanent bitmap - fill with '1s'. */
1037                 store->filemap = NULL;
1038                 store->file_pages = 0;
1039                 for (i = 0; i < chunks ; i++) {
1040                         /* if the disk bit is set, set the memory bit */
1041                         int needed = ((sector_t)(i+1) << (bitmap->counts.chunkshift)
1042                                       >= start);
1043                         bitmap_set_memory_bits(bitmap,
1044                                                (sector_t)i << bitmap->counts.chunkshift,
1045                                                needed);
1046                 }
1047                 return 0;
1048         }
1049
1050         outofdate = test_bit(BITMAP_STALE, &bitmap->flags);
1051         if (outofdate)
1052                 printk(KERN_INFO "%s: bitmap file is out of date, doing full "
1053                         "recovery\n", bmname(bitmap));
1054
1055         if (file && i_size_read(file->f_mapping->host) < store->bytes) {
1056                 printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
1057                        bmname(bitmap),
1058                        (unsigned long) i_size_read(file->f_mapping->host),
1059                        store->bytes);
1060                 goto err;
1061         }
1062
1063         oldindex = ~0L;
1064         offset = 0;
1065         if (!bitmap->mddev->bitmap_info.external)
1066                 offset = sizeof(bitmap_super_t);
1067
1068         if (mddev_is_clustered(bitmap->mddev))
1069                 node_offset = bitmap->cluster_slot * (DIV_ROUND_UP(store->bytes, PAGE_SIZE));
1070
1071         for (i = 0; i < chunks; i++) {
1072                 int b;
1073                 index = file_page_index(&bitmap->storage, i);
1074                 bit = file_page_offset(&bitmap->storage, i);
1075                 if (index != oldindex) { /* this is a new page, read it in */
1076                         int count;
1077                         /* unmap the old page, we're done with it */
1078                         if (index == store->file_pages-1)
1079                                 count = store->bytes - index * PAGE_SIZE;
1080                         else
1081                                 count = PAGE_SIZE;
1082                         page = store->filemap[index];
1083                         if (file)
1084                                 ret = read_page(file, index, bitmap,
1085                                                 count, page);
1086                         else
1087                                 ret = read_sb_page(
1088                                         bitmap->mddev,
1089                                         bitmap->mddev->bitmap_info.offset,
1090                                         page,
1091                                         index + node_offset, count);
1092
1093                         if (ret)
1094                                 goto err;
1095
1096                         oldindex = index;
1097
1098                         if (outofdate) {
1099                                 /*
1100                                  * if bitmap is out of date, dirty the
1101                                  * whole page and write it out
1102                                  */
1103                                 paddr = kmap_atomic(page);
1104                                 memset(paddr + offset, 0xff,
1105                                        PAGE_SIZE - offset);
1106                                 kunmap_atomic(paddr);
1107                                 write_page(bitmap, page, 1);
1108
1109                                 ret = -EIO;
1110                                 if (test_bit(BITMAP_WRITE_ERROR,
1111                                              &bitmap->flags))
1112                                         goto err;
1113                         }
1114                 }
1115                 paddr = kmap_atomic(page);
1116                 if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
1117                         b = test_bit(bit, paddr);
1118                 else
1119                         b = test_bit_le(bit, paddr);
1120                 kunmap_atomic(paddr);
1121                 if (b) {
1122                         /* if the disk bit is set, set the memory bit */
1123                         int needed = ((sector_t)(i+1) << bitmap->counts.chunkshift
1124                                       >= start);
1125                         bitmap_set_memory_bits(bitmap,
1126                                                (sector_t)i << bitmap->counts.chunkshift,
1127                                                needed);
1128                         bit_cnt++;
1129                 }
1130                 offset = 0;
1131         }
1132
1133         printk(KERN_INFO "%s: bitmap initialized from disk: "
1134                "read %lu pages, set %lu of %lu bits\n",
1135                bmname(bitmap), store->file_pages,
1136                bit_cnt, chunks);
1137
1138         return 0;
1139
1140  err:
1141         printk(KERN_INFO "%s: bitmap initialisation failed: %d\n",
1142                bmname(bitmap), ret);
1143         return ret;
1144 }
1145
1146 void bitmap_write_all(struct bitmap *bitmap)
1147 {
1148         /* We don't actually write all bitmap blocks here,
1149          * just flag them as needing to be written
1150          */
1151         int i;
1152
1153         if (!bitmap || !bitmap->storage.filemap)
1154                 return;
1155         if (bitmap->storage.file)
1156                 /* Only one copy, so nothing needed */
1157                 return;
1158
1159         for (i = 0; i < bitmap->storage.file_pages; i++)
1160                 set_page_attr(bitmap, i,
1161                               BITMAP_PAGE_NEEDWRITE);
1162         bitmap->allclean = 0;
1163 }
1164
1165 static void bitmap_count_page(struct bitmap_counts *bitmap,
1166                               sector_t offset, int inc)
1167 {
1168         sector_t chunk = offset >> bitmap->chunkshift;
1169         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1170         bitmap->bp[page].count += inc;
1171         bitmap_checkfree(bitmap, page);
1172 }
1173
1174 static void bitmap_set_pending(struct bitmap_counts *bitmap, sector_t offset)
1175 {
1176         sector_t chunk = offset >> bitmap->chunkshift;
1177         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1178         struct bitmap_page *bp = &bitmap->bp[page];
1179
1180         if (!bp->pending)
1181                 bp->pending = 1;
1182 }
1183
1184 static bitmap_counter_t *bitmap_get_counter(struct bitmap_counts *bitmap,
1185                                             sector_t offset, sector_t *blocks,
1186                                             int create);
1187
1188 /*
1189  * bitmap daemon -- periodically wakes up to clean bits and flush pages
1190  *                      out to disk
1191  */
1192
1193 void bitmap_daemon_work(struct mddev *mddev)
1194 {
1195         struct bitmap *bitmap;
1196         unsigned long j;
1197         unsigned long nextpage;
1198         sector_t blocks;
1199         struct bitmap_counts *counts;
1200
1201         /* Use a mutex to guard daemon_work against
1202          * bitmap_destroy.
1203          */
1204         mutex_lock(&mddev->bitmap_info.mutex);
1205         bitmap = mddev->bitmap;
1206         if (bitmap == NULL) {
1207                 mutex_unlock(&mddev->bitmap_info.mutex);
1208                 return;
1209         }
1210         if (time_before(jiffies, bitmap->daemon_lastrun
1211                         + mddev->bitmap_info.daemon_sleep))
1212                 goto done;
1213
1214         bitmap->daemon_lastrun = jiffies;
1215         if (bitmap->allclean) {
1216                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1217                 goto done;
1218         }
1219         bitmap->allclean = 1;
1220
1221         /* Any file-page which is PENDING now needs to be written.
1222          * So set NEEDWRITE now, then after we make any last-minute changes
1223          * we will write it.
1224          */
1225         for (j = 0; j < bitmap->storage.file_pages; j++)
1226                 if (test_and_clear_page_attr(bitmap, j,
1227                                              BITMAP_PAGE_PENDING))
1228                         set_page_attr(bitmap, j,
1229                                       BITMAP_PAGE_NEEDWRITE);
1230
1231         if (bitmap->need_sync &&
1232             mddev->bitmap_info.external == 0) {
1233                 /* Arrange for superblock update as well as
1234                  * other changes */
1235                 bitmap_super_t *sb;
1236                 bitmap->need_sync = 0;
1237                 if (bitmap->storage.filemap) {
1238                         sb = kmap_atomic(bitmap->storage.sb_page);
1239                         sb->events_cleared =
1240                                 cpu_to_le64(bitmap->events_cleared);
1241                         kunmap_atomic(sb);
1242                         set_page_attr(bitmap, 0,
1243                                       BITMAP_PAGE_NEEDWRITE);
1244                 }
1245         }
1246         /* Now look at the bitmap counters and if any are '2' or '1',
1247          * decrement and handle accordingly.
1248          */
1249         counts = &bitmap->counts;
1250         spin_lock_irq(&counts->lock);
1251         nextpage = 0;
1252         for (j = 0; j < counts->chunks; j++) {
1253                 bitmap_counter_t *bmc;
1254                 sector_t  block = (sector_t)j << counts->chunkshift;
1255
1256                 if (j == nextpage) {
1257                         nextpage += PAGE_COUNTER_RATIO;
1258                         if (!counts->bp[j >> PAGE_COUNTER_SHIFT].pending) {
1259                                 j |= PAGE_COUNTER_MASK;
1260                                 continue;
1261                         }
1262                         counts->bp[j >> PAGE_COUNTER_SHIFT].pending = 0;
1263                 }
1264                 bmc = bitmap_get_counter(counts,
1265                                          block,
1266                                          &blocks, 0);
1267
1268                 if (!bmc) {
1269                         j |= PAGE_COUNTER_MASK;
1270                         continue;
1271                 }
1272                 if (*bmc == 1 && !bitmap->need_sync) {
1273                         /* We can clear the bit */
1274                         *bmc = 0;
1275                         bitmap_count_page(counts, block, -1);
1276                         bitmap_file_clear_bit(bitmap, block);
1277                 } else if (*bmc && *bmc <= 2) {
1278                         *bmc = 1;
1279                         bitmap_set_pending(counts, block);
1280                         bitmap->allclean = 0;
1281                 }
1282         }
1283         spin_unlock_irq(&counts->lock);
1284
1285         /* Now start writeout on any page in NEEDWRITE that isn't DIRTY.
1286          * DIRTY pages need to be written by bitmap_unplug so it can wait
1287          * for them.
1288          * If we find any DIRTY page we stop there and let bitmap_unplug
1289          * handle all the rest.  This is important in the case where
1290          * the first blocking holds the superblock and it has been updated.
1291          * We mustn't write any other blocks before the superblock.
1292          */
1293         for (j = 0;
1294              j < bitmap->storage.file_pages
1295                      && !test_bit(BITMAP_STALE, &bitmap->flags);
1296              j++) {
1297                 if (test_page_attr(bitmap, j,
1298                                    BITMAP_PAGE_DIRTY))
1299                         /* bitmap_unplug will handle the rest */
1300                         break;
1301                 if (test_and_clear_page_attr(bitmap, j,
1302                                              BITMAP_PAGE_NEEDWRITE)) {
1303                         write_page(bitmap, bitmap->storage.filemap[j], 0);
1304                 }
1305         }
1306
1307  done:
1308         if (bitmap->allclean == 0)
1309                 mddev->thread->timeout =
1310                         mddev->bitmap_info.daemon_sleep;
1311         mutex_unlock(&mddev->bitmap_info.mutex);
1312 }
1313
1314 static bitmap_counter_t *bitmap_get_counter(struct bitmap_counts *bitmap,
1315                                             sector_t offset, sector_t *blocks,
1316                                             int create)
1317 __releases(bitmap->lock)
1318 __acquires(bitmap->lock)
1319 {
1320         /* If 'create', we might release the lock and reclaim it.
1321          * The lock must have been taken with interrupts enabled.
1322          * If !create, we don't release the lock.
1323          */
1324         sector_t chunk = offset >> bitmap->chunkshift;
1325         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1326         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1327         sector_t csize;
1328         int err;
1329
1330         err = bitmap_checkpage(bitmap, page, create);
1331
1332         if (bitmap->bp[page].hijacked ||
1333             bitmap->bp[page].map == NULL)
1334                 csize = ((sector_t)1) << (bitmap->chunkshift +
1335                                           PAGE_COUNTER_SHIFT - 1);
1336         else
1337                 csize = ((sector_t)1) << bitmap->chunkshift;
1338         *blocks = csize - (offset & (csize - 1));
1339
1340         if (err < 0)
1341                 return NULL;
1342
1343         /* now locked ... */
1344
1345         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1346                 /* should we use the first or second counter field
1347                  * of the hijacked pointer? */
1348                 int hi = (pageoff > PAGE_COUNTER_MASK);
1349                 return  &((bitmap_counter_t *)
1350                           &bitmap->bp[page].map)[hi];
1351         } else /* page is allocated */
1352                 return (bitmap_counter_t *)
1353                         &(bitmap->bp[page].map[pageoff]);
1354 }
1355
1356 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1357 {
1358         if (!bitmap)
1359                 return 0;
1360
1361         if (behind) {
1362                 int bw;
1363                 atomic_inc(&bitmap->behind_writes);
1364                 bw = atomic_read(&bitmap->behind_writes);
1365                 if (bw > bitmap->behind_writes_used)
1366                         bitmap->behind_writes_used = bw;
1367
1368                 pr_debug("inc write-behind count %d/%lu\n",
1369                          bw, bitmap->mddev->bitmap_info.max_write_behind);
1370         }
1371
1372         while (sectors) {
1373                 sector_t blocks;
1374                 bitmap_counter_t *bmc;
1375
1376                 spin_lock_irq(&bitmap->counts.lock);
1377                 bmc = bitmap_get_counter(&bitmap->counts, offset, &blocks, 1);
1378                 if (!bmc) {
1379                         spin_unlock_irq(&bitmap->counts.lock);
1380                         return 0;
1381                 }
1382
1383                 if (unlikely(COUNTER(*bmc) == COUNTER_MAX)) {
1384                         DEFINE_WAIT(__wait);
1385                         /* note that it is safe to do the prepare_to_wait
1386                          * after the test as long as we do it before dropping
1387                          * the spinlock.
1388                          */
1389                         prepare_to_wait(&bitmap->overflow_wait, &__wait,
1390                                         TASK_UNINTERRUPTIBLE);
1391                         spin_unlock_irq(&bitmap->counts.lock);
1392                         schedule();
1393                         finish_wait(&bitmap->overflow_wait, &__wait);
1394                         continue;
1395                 }
1396
1397                 switch (*bmc) {
1398                 case 0:
1399                         bitmap_file_set_bit(bitmap, offset);
1400                         bitmap_count_page(&bitmap->counts, offset, 1);
1401                         /* fall through */
1402                 case 1:
1403                         *bmc = 2;
1404                 }
1405
1406                 (*bmc)++;
1407
1408                 spin_unlock_irq(&bitmap->counts.lock);
1409
1410                 offset += blocks;
1411                 if (sectors > blocks)
1412                         sectors -= blocks;
1413                 else
1414                         sectors = 0;
1415         }
1416         return 0;
1417 }
1418 EXPORT_SYMBOL(bitmap_startwrite);
1419
1420 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1421                      int success, int behind)
1422 {
1423         if (!bitmap)
1424                 return;
1425         if (behind) {
1426                 if (atomic_dec_and_test(&bitmap->behind_writes))
1427                         wake_up(&bitmap->behind_wait);
1428                 pr_debug("dec write-behind count %d/%lu\n",
1429                          atomic_read(&bitmap->behind_writes),
1430                          bitmap->mddev->bitmap_info.max_write_behind);
1431         }
1432
1433         while (sectors) {
1434                 sector_t blocks;
1435                 unsigned long flags;
1436                 bitmap_counter_t *bmc;
1437
1438                 spin_lock_irqsave(&bitmap->counts.lock, flags);
1439                 bmc = bitmap_get_counter(&bitmap->counts, offset, &blocks, 0);
1440                 if (!bmc) {
1441                         spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1442                         return;
1443                 }
1444
1445                 if (success && !bitmap->mddev->degraded &&
1446                     bitmap->events_cleared < bitmap->mddev->events) {
1447                         bitmap->events_cleared = bitmap->mddev->events;
1448                         bitmap->need_sync = 1;
1449                         sysfs_notify_dirent_safe(bitmap->sysfs_can_clear);
1450                 }
1451
1452                 if (!success && !NEEDED(*bmc))
1453                         *bmc |= NEEDED_MASK;
1454
1455                 if (COUNTER(*bmc) == COUNTER_MAX)
1456                         wake_up(&bitmap->overflow_wait);
1457
1458                 (*bmc)--;
1459                 if (*bmc <= 2) {
1460                         bitmap_set_pending(&bitmap->counts, offset);
1461                         bitmap->allclean = 0;
1462                 }
1463                 spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1464                 offset += blocks;
1465                 if (sectors > blocks)
1466                         sectors -= blocks;
1467                 else
1468                         sectors = 0;
1469         }
1470 }
1471 EXPORT_SYMBOL(bitmap_endwrite);
1472
1473 static int __bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1474                                int degraded)
1475 {
1476         bitmap_counter_t *bmc;
1477         int rv;
1478         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1479                 *blocks = 1024;
1480                 return 1; /* always resync if no bitmap */
1481         }
1482         spin_lock_irq(&bitmap->counts.lock);
1483         bmc = bitmap_get_counter(&bitmap->counts, offset, blocks, 0);
1484         rv = 0;
1485         if (bmc) {
1486                 /* locked */
1487                 if (RESYNC(*bmc))
1488                         rv = 1;
1489                 else if (NEEDED(*bmc)) {
1490                         rv = 1;
1491                         if (!degraded) { /* don't set/clear bits if degraded */
1492                                 *bmc |= RESYNC_MASK;
1493                                 *bmc &= ~NEEDED_MASK;
1494                         }
1495                 }
1496         }
1497         spin_unlock_irq(&bitmap->counts.lock);
1498         return rv;
1499 }
1500
1501 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1502                       int degraded)
1503 {
1504         /* bitmap_start_sync must always report on multiples of whole
1505          * pages, otherwise resync (which is very PAGE_SIZE based) will
1506          * get confused.
1507          * So call __bitmap_start_sync repeatedly (if needed) until
1508          * At least PAGE_SIZE>>9 blocks are covered.
1509          * Return the 'or' of the result.
1510          */
1511         int rv = 0;
1512         sector_t blocks1;
1513
1514         *blocks = 0;
1515         while (*blocks < (PAGE_SIZE>>9)) {
1516                 rv |= __bitmap_start_sync(bitmap, offset,
1517                                           &blocks1, degraded);
1518                 offset += blocks1;
1519                 *blocks += blocks1;
1520         }
1521         return rv;
1522 }
1523 EXPORT_SYMBOL(bitmap_start_sync);
1524
1525 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks, int aborted)
1526 {
1527         bitmap_counter_t *bmc;
1528         unsigned long flags;
1529
1530         if (bitmap == NULL) {
1531                 *blocks = 1024;
1532                 return;
1533         }
1534         spin_lock_irqsave(&bitmap->counts.lock, flags);
1535         bmc = bitmap_get_counter(&bitmap->counts, offset, blocks, 0);
1536         if (bmc == NULL)
1537                 goto unlock;
1538         /* locked */
1539         if (RESYNC(*bmc)) {
1540                 *bmc &= ~RESYNC_MASK;
1541
1542                 if (!NEEDED(*bmc) && aborted)
1543                         *bmc |= NEEDED_MASK;
1544                 else {
1545                         if (*bmc <= 2) {
1546                                 bitmap_set_pending(&bitmap->counts, offset);
1547                                 bitmap->allclean = 0;
1548                         }
1549                 }
1550         }
1551  unlock:
1552         spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1553 }
1554 EXPORT_SYMBOL(bitmap_end_sync);
1555
1556 void bitmap_close_sync(struct bitmap *bitmap)
1557 {
1558         /* Sync has finished, and any bitmap chunks that weren't synced
1559          * properly have been aborted.  It remains to us to clear the
1560          * RESYNC bit wherever it is still on
1561          */
1562         sector_t sector = 0;
1563         sector_t blocks;
1564         if (!bitmap)
1565                 return;
1566         while (sector < bitmap->mddev->resync_max_sectors) {
1567                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1568                 sector += blocks;
1569         }
1570 }
1571 EXPORT_SYMBOL(bitmap_close_sync);
1572
1573 void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector, bool force)
1574 {
1575         sector_t s = 0;
1576         sector_t blocks;
1577
1578         if (!bitmap)
1579                 return;
1580         if (sector == 0) {
1581                 bitmap->last_end_sync = jiffies;
1582                 return;
1583         }
1584         if (!force && time_before(jiffies, (bitmap->last_end_sync
1585                                   + bitmap->mddev->bitmap_info.daemon_sleep)))
1586                 return;
1587         wait_event(bitmap->mddev->recovery_wait,
1588                    atomic_read(&bitmap->mddev->recovery_active) == 0);
1589
1590         bitmap->mddev->curr_resync_completed = sector;
1591         set_bit(MD_CHANGE_CLEAN, &bitmap->mddev->flags);
1592         sector &= ~((1ULL << bitmap->counts.chunkshift) - 1);
1593         s = 0;
1594         while (s < sector && s < bitmap->mddev->resync_max_sectors) {
1595                 bitmap_end_sync(bitmap, s, &blocks, 0);
1596                 s += blocks;
1597         }
1598         bitmap->last_end_sync = jiffies;
1599         sysfs_notify(&bitmap->mddev->kobj, NULL, "sync_completed");
1600 }
1601 EXPORT_SYMBOL(bitmap_cond_end_sync);
1602
1603 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1604 {
1605         /* For each chunk covered by any of these sectors, set the
1606          * counter to 2 and possibly set resync_needed.  They should all
1607          * be 0 at this point
1608          */
1609
1610         sector_t secs;
1611         bitmap_counter_t *bmc;
1612         spin_lock_irq(&bitmap->counts.lock);
1613         bmc = bitmap_get_counter(&bitmap->counts, offset, &secs, 1);
1614         if (!bmc) {
1615                 spin_unlock_irq(&bitmap->counts.lock);
1616                 return;
1617         }
1618         if (!*bmc) {
1619                 *bmc = 2;
1620                 bitmap_count_page(&bitmap->counts, offset, 1);
1621                 bitmap_set_pending(&bitmap->counts, offset);
1622                 bitmap->allclean = 0;
1623         }
1624         if (needed)
1625                 *bmc |= NEEDED_MASK;
1626         spin_unlock_irq(&bitmap->counts.lock);
1627 }
1628
1629 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
1630 void bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1631 {
1632         unsigned long chunk;
1633
1634         for (chunk = s; chunk <= e; chunk++) {
1635                 sector_t sec = (sector_t)chunk << bitmap->counts.chunkshift;
1636                 bitmap_set_memory_bits(bitmap, sec, 1);
1637                 bitmap_file_set_bit(bitmap, sec);
1638                 if (sec < bitmap->mddev->recovery_cp)
1639                         /* We are asserting that the array is dirty,
1640                          * so move the recovery_cp address back so
1641                          * that it is obvious that it is dirty
1642                          */
1643                         bitmap->mddev->recovery_cp = sec;
1644         }
1645 }
1646
1647 /*
1648  * flush out any pending updates
1649  */
1650 void bitmap_flush(struct mddev *mddev)
1651 {
1652         struct bitmap *bitmap = mddev->bitmap;
1653         long sleep;
1654
1655         if (!bitmap) /* there was no bitmap */
1656                 return;
1657
1658         /* run the daemon_work three time to ensure everything is flushed
1659          * that can be
1660          */
1661         sleep = mddev->bitmap_info.daemon_sleep * 2;
1662         bitmap->daemon_lastrun -= sleep;
1663         bitmap_daemon_work(mddev);
1664         bitmap->daemon_lastrun -= sleep;
1665         bitmap_daemon_work(mddev);
1666         bitmap->daemon_lastrun -= sleep;
1667         bitmap_daemon_work(mddev);
1668         bitmap_update_sb(bitmap);
1669 }
1670
1671 /*
1672  * free memory that was allocated
1673  */
1674 static void bitmap_free(struct bitmap *bitmap)
1675 {
1676         unsigned long k, pages;
1677         struct bitmap_page *bp;
1678
1679         if (!bitmap) /* there was no bitmap */
1680                 return;
1681
1682         if (mddev_is_clustered(bitmap->mddev) && bitmap->mddev->cluster_info &&
1683                 bitmap->cluster_slot == md_cluster_ops->slot_number(bitmap->mddev))
1684                 md_cluster_stop(bitmap->mddev);
1685
1686         /* Shouldn't be needed - but just in case.... */
1687         wait_event(bitmap->write_wait,
1688                    atomic_read(&bitmap->pending_writes) == 0);
1689
1690         /* release the bitmap file  */
1691         bitmap_file_unmap(&bitmap->storage);
1692
1693         bp = bitmap->counts.bp;
1694         pages = bitmap->counts.pages;
1695
1696         /* free all allocated memory */
1697
1698         if (bp) /* deallocate the page memory */
1699                 for (k = 0; k < pages; k++)
1700                         if (bp[k].map && !bp[k].hijacked)
1701                                 kfree(bp[k].map);
1702         kfree(bp);
1703         kfree(bitmap);
1704 }
1705
1706 void bitmap_destroy(struct mddev *mddev)
1707 {
1708         struct bitmap *bitmap = mddev->bitmap;
1709
1710         if (!bitmap) /* there was no bitmap */
1711                 return;
1712
1713         mutex_lock(&mddev->bitmap_info.mutex);
1714         spin_lock(&mddev->lock);
1715         mddev->bitmap = NULL; /* disconnect from the md device */
1716         spin_unlock(&mddev->lock);
1717         mutex_unlock(&mddev->bitmap_info.mutex);
1718         if (mddev->thread)
1719                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1720
1721         if (bitmap->sysfs_can_clear)
1722                 sysfs_put(bitmap->sysfs_can_clear);
1723
1724         bitmap_free(bitmap);
1725 }
1726
1727 /*
1728  * initialize the bitmap structure
1729  * if this returns an error, bitmap_destroy must be called to do clean up
1730  */
1731 struct bitmap *bitmap_create(struct mddev *mddev, int slot)
1732 {
1733         struct bitmap *bitmap;
1734         sector_t blocks = mddev->resync_max_sectors;
1735         struct file *file = mddev->bitmap_info.file;
1736         int err;
1737         struct kernfs_node *bm = NULL;
1738
1739         BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
1740
1741         BUG_ON(file && mddev->bitmap_info.offset);
1742
1743         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1744         if (!bitmap)
1745                 return ERR_PTR(-ENOMEM);
1746
1747         spin_lock_init(&bitmap->counts.lock);
1748         atomic_set(&bitmap->pending_writes, 0);
1749         init_waitqueue_head(&bitmap->write_wait);
1750         init_waitqueue_head(&bitmap->overflow_wait);
1751         init_waitqueue_head(&bitmap->behind_wait);
1752
1753         bitmap->mddev = mddev;
1754         bitmap->cluster_slot = slot;
1755
1756         if (mddev->kobj.sd)
1757                 bm = sysfs_get_dirent(mddev->kobj.sd, "bitmap");
1758         if (bm) {
1759                 bitmap->sysfs_can_clear = sysfs_get_dirent(bm, "can_clear");
1760                 sysfs_put(bm);
1761         } else
1762                 bitmap->sysfs_can_clear = NULL;
1763
1764         bitmap->storage.file = file;
1765         if (file) {
1766                 get_file(file);
1767                 /* As future accesses to this file will use bmap,
1768                  * and bypass the page cache, we must sync the file
1769                  * first.
1770                  */
1771                 vfs_fsync(file, 1);
1772         }
1773         /* read superblock from bitmap file (this sets mddev->bitmap_info.chunksize) */
1774         if (!mddev->bitmap_info.external) {
1775                 /*
1776                  * If 'MD_ARRAY_FIRST_USE' is set, then device-mapper is
1777                  * instructing us to create a new on-disk bitmap instance.
1778                  */
1779                 if (test_and_clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags))
1780                         err = bitmap_new_disk_sb(bitmap);
1781                 else
1782                         err = bitmap_read_sb(bitmap);
1783         } else {
1784                 err = 0;
1785                 if (mddev->bitmap_info.chunksize == 0 ||
1786                     mddev->bitmap_info.daemon_sleep == 0)
1787                         /* chunksize and time_base need to be
1788                          * set first. */
1789                         err = -EINVAL;
1790         }
1791         if (err)
1792                 goto error;
1793
1794         bitmap->daemon_lastrun = jiffies;
1795         err = bitmap_resize(bitmap, blocks, mddev->bitmap_info.chunksize, 1);
1796         if (err)
1797                 goto error;
1798
1799         printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
1800                bitmap->counts.pages, bmname(bitmap));
1801
1802         err = test_bit(BITMAP_WRITE_ERROR, &bitmap->flags) ? -EIO : 0;
1803         if (err)
1804                 goto error;
1805
1806         return bitmap;
1807  error:
1808         bitmap_free(bitmap);
1809         return ERR_PTR(err);
1810 }
1811
1812 int bitmap_load(struct mddev *mddev)
1813 {
1814         int err = 0;
1815         sector_t start = 0;
1816         sector_t sector = 0;
1817         struct bitmap *bitmap = mddev->bitmap;
1818
1819         if (!bitmap)
1820                 goto out;
1821
1822         /* Clear out old bitmap info first:  Either there is none, or we
1823          * are resuming after someone else has possibly changed things,
1824          * so we should forget old cached info.
1825          * All chunks should be clean, but some might need_sync.
1826          */
1827         while (sector < mddev->resync_max_sectors) {
1828                 sector_t blocks;
1829                 bitmap_start_sync(bitmap, sector, &blocks, 0);
1830                 sector += blocks;
1831         }
1832         bitmap_close_sync(bitmap);
1833
1834         if (mddev->degraded == 0
1835             || bitmap->events_cleared == mddev->events)
1836                 /* no need to keep dirty bits to optimise a
1837                  * re-add of a missing device */
1838                 start = mddev->recovery_cp;
1839
1840         mutex_lock(&mddev->bitmap_info.mutex);
1841         err = bitmap_init_from_disk(bitmap, start);
1842         mutex_unlock(&mddev->bitmap_info.mutex);
1843
1844         if (err)
1845                 goto out;
1846         clear_bit(BITMAP_STALE, &bitmap->flags);
1847
1848         /* Kick recovery in case any bits were set */
1849         set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
1850
1851         mddev->thread->timeout = mddev->bitmap_info.daemon_sleep;
1852         md_wakeup_thread(mddev->thread);
1853
1854         bitmap_update_sb(bitmap);
1855
1856         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
1857                 err = -EIO;
1858 out:
1859         return err;
1860 }
1861 EXPORT_SYMBOL_GPL(bitmap_load);
1862
1863 /* Loads the bitmap associated with slot and copies the resync information
1864  * to our bitmap
1865  */
1866 int bitmap_copy_from_slot(struct mddev *mddev, int slot,
1867                 sector_t *low, sector_t *high, bool clear_bits)
1868 {
1869         int rv = 0, i, j;
1870         sector_t block, lo = 0, hi = 0;
1871         struct bitmap_counts *counts;
1872         struct bitmap *bitmap = bitmap_create(mddev, slot);
1873
1874         if (IS_ERR(bitmap))
1875                 return PTR_ERR(bitmap);
1876
1877         rv = bitmap_init_from_disk(bitmap, 0);
1878         if (rv)
1879                 goto err;
1880
1881         counts = &bitmap->counts;
1882         for (j = 0; j < counts->chunks; j++) {
1883                 block = (sector_t)j << counts->chunkshift;
1884                 if (bitmap_file_test_bit(bitmap, block)) {
1885                         if (!lo)
1886                                 lo = block;
1887                         hi = block;
1888                         bitmap_file_clear_bit(bitmap, block);
1889                         bitmap_set_memory_bits(mddev->bitmap, block, 1);
1890                         bitmap_file_set_bit(mddev->bitmap, block);
1891                 }
1892         }
1893
1894         if (clear_bits) {
1895                 bitmap_update_sb(bitmap);
1896                 /* Setting this for the ev_page should be enough.
1897                  * And we do not require both write_all and PAGE_DIRT either
1898                  */
1899                 for (i = 0; i < bitmap->storage.file_pages; i++)
1900                         set_page_attr(bitmap, i, BITMAP_PAGE_DIRTY);
1901                 bitmap_write_all(bitmap);
1902                 bitmap_unplug(bitmap);
1903         }
1904         *low = lo;
1905         *high = hi;
1906 err:
1907         bitmap_free(bitmap);
1908         return rv;
1909 }
1910 EXPORT_SYMBOL_GPL(bitmap_copy_from_slot);
1911
1912
1913 void bitmap_status(struct seq_file *seq, struct bitmap *bitmap)
1914 {
1915         unsigned long chunk_kb;
1916         struct bitmap_counts *counts;
1917
1918         if (!bitmap)
1919                 return;
1920
1921         counts = &bitmap->counts;
1922
1923         chunk_kb = bitmap->mddev->bitmap_info.chunksize >> 10;
1924         seq_printf(seq, "bitmap: %lu/%lu pages [%luKB], "
1925                    "%lu%s chunk",
1926                    counts->pages - counts->missing_pages,
1927                    counts->pages,
1928                    (counts->pages - counts->missing_pages)
1929                    << (PAGE_SHIFT - 10),
1930                    chunk_kb ? chunk_kb : bitmap->mddev->bitmap_info.chunksize,
1931                    chunk_kb ? "KB" : "B");
1932         if (bitmap->storage.file) {
1933                 seq_printf(seq, ", file: ");
1934                 seq_file_path(seq, bitmap->storage.file, " \t\n");
1935         }
1936
1937         seq_printf(seq, "\n");
1938 }
1939
1940 int bitmap_resize(struct bitmap *bitmap, sector_t blocks,
1941                   int chunksize, int init)
1942 {
1943         /* If chunk_size is 0, choose an appropriate chunk size.
1944          * Then possibly allocate new storage space.
1945          * Then quiesce, copy bits, replace bitmap, and re-start
1946          *
1947          * This function is called both to set up the initial bitmap
1948          * and to resize the bitmap while the array is active.
1949          * If this happens as a result of the array being resized,
1950          * chunksize will be zero, and we need to choose a suitable
1951          * chunksize, otherwise we use what we are given.
1952          */
1953         struct bitmap_storage store;
1954         struct bitmap_counts old_counts;
1955         unsigned long chunks;
1956         sector_t block;
1957         sector_t old_blocks, new_blocks;
1958         int chunkshift;
1959         int ret = 0;
1960         long pages;
1961         struct bitmap_page *new_bp;
1962
1963         if (chunksize == 0) {
1964                 /* If there is enough space, leave the chunk size unchanged,
1965                  * else increase by factor of two until there is enough space.
1966                  */
1967                 long bytes;
1968                 long space = bitmap->mddev->bitmap_info.space;
1969
1970                 if (space == 0) {
1971                         /* We don't know how much space there is, so limit
1972                          * to current size - in sectors.
1973                          */
1974                         bytes = DIV_ROUND_UP(bitmap->counts.chunks, 8);
1975                         if (!bitmap->mddev->bitmap_info.external)
1976                                 bytes += sizeof(bitmap_super_t);
1977                         space = DIV_ROUND_UP(bytes, 512);
1978                         bitmap->mddev->bitmap_info.space = space;
1979                 }
1980                 chunkshift = bitmap->counts.chunkshift;
1981                 chunkshift--;
1982                 do {
1983                         /* 'chunkshift' is shift from block size to chunk size */
1984                         chunkshift++;
1985                         chunks = DIV_ROUND_UP_SECTOR_T(blocks, 1 << chunkshift);
1986                         bytes = DIV_ROUND_UP(chunks, 8);
1987                         if (!bitmap->mddev->bitmap_info.external)
1988                                 bytes += sizeof(bitmap_super_t);
1989                 } while (bytes > (space << 9));
1990         } else
1991                 chunkshift = ffz(~chunksize) - BITMAP_BLOCK_SHIFT;
1992
1993         chunks = DIV_ROUND_UP_SECTOR_T(blocks, 1 << chunkshift);
1994         memset(&store, 0, sizeof(store));
1995         if (bitmap->mddev->bitmap_info.offset || bitmap->mddev->bitmap_info.file)
1996                 ret = bitmap_storage_alloc(&store, chunks,
1997                                            !bitmap->mddev->bitmap_info.external,
1998                                            mddev_is_clustered(bitmap->mddev)
1999                                            ? bitmap->cluster_slot : 0);
2000         if (ret)
2001                 goto err;
2002
2003         pages = DIV_ROUND_UP(chunks, PAGE_COUNTER_RATIO);
2004
2005         new_bp = kzalloc(pages * sizeof(*new_bp), GFP_KERNEL);
2006         ret = -ENOMEM;
2007         if (!new_bp) {
2008                 bitmap_file_unmap(&store);
2009                 goto err;
2010         }
2011
2012         if (!init)
2013                 bitmap->mddev->pers->quiesce(bitmap->mddev, 1);
2014
2015         store.file = bitmap->storage.file;
2016         bitmap->storage.file = NULL;
2017
2018         if (store.sb_page && bitmap->storage.sb_page)
2019                 memcpy(page_address(store.sb_page),
2020                        page_address(bitmap->storage.sb_page),
2021                        sizeof(bitmap_super_t));
2022         bitmap_file_unmap(&bitmap->storage);
2023         bitmap->storage = store;
2024
2025         old_counts = bitmap->counts;
2026         bitmap->counts.bp = new_bp;
2027         bitmap->counts.pages = pages;
2028         bitmap->counts.missing_pages = pages;
2029         bitmap->counts.chunkshift = chunkshift;
2030         bitmap->counts.chunks = chunks;
2031         bitmap->mddev->bitmap_info.chunksize = 1 << (chunkshift +
2032                                                      BITMAP_BLOCK_SHIFT);
2033
2034         blocks = min(old_counts.chunks << old_counts.chunkshift,
2035                      chunks << chunkshift);
2036
2037         spin_lock_irq(&bitmap->counts.lock);
2038         for (block = 0; block < blocks; ) {
2039                 bitmap_counter_t *bmc_old, *bmc_new;
2040                 int set;
2041
2042                 bmc_old = bitmap_get_counter(&old_counts, block,
2043                                              &old_blocks, 0);
2044                 set = bmc_old && NEEDED(*bmc_old);
2045
2046                 if (set) {
2047                         bmc_new = bitmap_get_counter(&bitmap->counts, block,
2048                                                      &new_blocks, 1);
2049                         if (*bmc_new == 0) {
2050                                 /* need to set on-disk bits too. */
2051                                 sector_t end = block + new_blocks;
2052                                 sector_t start = block >> chunkshift;
2053                                 start <<= chunkshift;
2054                                 while (start < end) {
2055                                         bitmap_file_set_bit(bitmap, block);
2056                                         start += 1 << chunkshift;
2057                                 }
2058                                 *bmc_new = 2;
2059                                 bitmap_count_page(&bitmap->counts,
2060                                                   block, 1);
2061                                 bitmap_set_pending(&bitmap->counts,
2062                                                    block);
2063                         }
2064                         *bmc_new |= NEEDED_MASK;
2065                         if (new_blocks < old_blocks)
2066                                 old_blocks = new_blocks;
2067                 }
2068                 block += old_blocks;
2069         }
2070
2071         if (!init) {
2072                 int i;
2073                 while (block < (chunks << chunkshift)) {
2074                         bitmap_counter_t *bmc;
2075                         bmc = bitmap_get_counter(&bitmap->counts, block,
2076                                                  &new_blocks, 1);
2077                         if (bmc) {
2078                                 /* new space.  It needs to be resynced, so
2079                                  * we set NEEDED_MASK.
2080                                  */
2081                                 if (*bmc == 0) {
2082                                         *bmc = NEEDED_MASK | 2;
2083                                         bitmap_count_page(&bitmap->counts,
2084                                                           block, 1);
2085                                         bitmap_set_pending(&bitmap->counts,
2086                                                            block);
2087                                 }
2088                         }
2089                         block += new_blocks;
2090                 }
2091                 for (i = 0; i < bitmap->storage.file_pages; i++)
2092                         set_page_attr(bitmap, i, BITMAP_PAGE_DIRTY);
2093         }
2094         spin_unlock_irq(&bitmap->counts.lock);
2095
2096         if (!init) {
2097                 bitmap_unplug(bitmap);
2098                 bitmap->mddev->pers->quiesce(bitmap->mddev, 0);
2099         }
2100         ret = 0;
2101 err:
2102         return ret;
2103 }
2104 EXPORT_SYMBOL_GPL(bitmap_resize);
2105
2106 static ssize_t
2107 location_show(struct mddev *mddev, char *page)
2108 {
2109         ssize_t len;
2110         if (mddev->bitmap_info.file)
2111                 len = sprintf(page, "file");
2112         else if (mddev->bitmap_info.offset)
2113                 len = sprintf(page, "%+lld", (long long)mddev->bitmap_info.offset);
2114         else
2115                 len = sprintf(page, "none");
2116         len += sprintf(page+len, "\n");
2117         return len;
2118 }
2119
2120 static ssize_t
2121 location_store(struct mddev *mddev, const char *buf, size_t len)
2122 {
2123
2124         if (mddev->pers) {
2125                 if (!mddev->pers->quiesce)
2126                         return -EBUSY;
2127                 if (mddev->recovery || mddev->sync_thread)
2128                         return -EBUSY;
2129         }
2130
2131         if (mddev->bitmap || mddev->bitmap_info.file ||
2132             mddev->bitmap_info.offset) {
2133                 /* bitmap already configured.  Only option is to clear it */
2134                 if (strncmp(buf, "none", 4) != 0)
2135                         return -EBUSY;
2136                 if (mddev->pers) {
2137                         mddev->pers->quiesce(mddev, 1);
2138                         bitmap_destroy(mddev);
2139                         mddev->pers->quiesce(mddev, 0);
2140                 }
2141                 mddev->bitmap_info.offset = 0;
2142                 if (mddev->bitmap_info.file) {
2143                         struct file *f = mddev->bitmap_info.file;
2144                         mddev->bitmap_info.file = NULL;
2145                         fput(f);
2146                 }
2147         } else {
2148                 /* No bitmap, OK to set a location */
2149                 long long offset;
2150                 if (strncmp(buf, "none", 4) == 0)
2151                         /* nothing to be done */;
2152                 else if (strncmp(buf, "file:", 5) == 0) {
2153                         /* Not supported yet */
2154                         return -EINVAL;
2155                 } else {
2156                         int rv;
2157                         if (buf[0] == '+')
2158                                 rv = kstrtoll(buf+1, 10, &offset);
2159                         else
2160                                 rv = kstrtoll(buf, 10, &offset);
2161                         if (rv)
2162                                 return rv;
2163                         if (offset == 0)
2164                                 return -EINVAL;
2165                         if (mddev->bitmap_info.external == 0 &&
2166                             mddev->major_version == 0 &&
2167                             offset != mddev->bitmap_info.default_offset)
2168                                 return -EINVAL;
2169                         mddev->bitmap_info.offset = offset;
2170                         if (mddev->pers) {
2171                                 struct bitmap *bitmap;
2172                                 mddev->pers->quiesce(mddev, 1);
2173                                 bitmap = bitmap_create(mddev, -1);
2174                                 if (IS_ERR(bitmap))
2175                                         rv = PTR_ERR(bitmap);
2176                                 else {
2177                                         mddev->bitmap = bitmap;
2178                                         rv = bitmap_load(mddev);
2179                                         if (rv) {
2180                                                 bitmap_destroy(mddev);
2181                                                 mddev->bitmap_info.offset = 0;
2182                                         }
2183                                 }
2184                                 mddev->pers->quiesce(mddev, 0);
2185                                 if (rv)
2186                                         return rv;
2187                         }
2188                 }
2189         }
2190         if (!mddev->external) {
2191                 /* Ensure new bitmap info is stored in
2192                  * metadata promptly.
2193                  */
2194                 set_bit(MD_CHANGE_DEVS, &mddev->flags);
2195                 md_wakeup_thread(mddev->thread);
2196         }
2197         return len;
2198 }
2199
2200 static struct md_sysfs_entry bitmap_location =
2201 __ATTR(location, S_IRUGO|S_IWUSR, location_show, location_store);
2202
2203 /* 'bitmap/space' is the space available at 'location' for the
2204  * bitmap.  This allows the kernel to know when it is safe to
2205  * resize the bitmap to match a resized array.
2206  */
2207 static ssize_t
2208 space_show(struct mddev *mddev, char *page)
2209 {
2210         return sprintf(page, "%lu\n", mddev->bitmap_info.space);
2211 }
2212
2213 static ssize_t
2214 space_store(struct mddev *mddev, const char *buf, size_t len)
2215 {
2216         unsigned long sectors;
2217         int rv;
2218
2219         rv = kstrtoul(buf, 10, &sectors);
2220         if (rv)
2221                 return rv;
2222
2223         if (sectors == 0)
2224                 return -EINVAL;
2225
2226         if (mddev->bitmap &&
2227             sectors < (mddev->bitmap->storage.bytes + 511) >> 9)
2228                 return -EFBIG; /* Bitmap is too big for this small space */
2229
2230         /* could make sure it isn't too big, but that isn't really
2231          * needed - user-space should be careful.
2232          */
2233         mddev->bitmap_info.space = sectors;
2234         return len;
2235 }
2236
2237 static struct md_sysfs_entry bitmap_space =
2238 __ATTR(space, S_IRUGO|S_IWUSR, space_show, space_store);
2239
2240 static ssize_t
2241 timeout_show(struct mddev *mddev, char *page)
2242 {
2243         ssize_t len;
2244         unsigned long secs = mddev->bitmap_info.daemon_sleep / HZ;
2245         unsigned long jifs = mddev->bitmap_info.daemon_sleep % HZ;
2246
2247         len = sprintf(page, "%lu", secs);
2248         if (jifs)
2249                 len += sprintf(page+len, ".%03u", jiffies_to_msecs(jifs));
2250         len += sprintf(page+len, "\n");
2251         return len;
2252 }
2253
2254 static ssize_t
2255 timeout_store(struct mddev *mddev, const char *buf, size_t len)
2256 {
2257         /* timeout can be set at any time */
2258         unsigned long timeout;
2259         int rv = strict_strtoul_scaled(buf, &timeout, 4);
2260         if (rv)
2261                 return rv;
2262
2263         /* just to make sure we don't overflow... */
2264         if (timeout >= LONG_MAX / HZ)
2265                 return -EINVAL;
2266
2267         timeout = timeout * HZ / 10000;
2268
2269         if (timeout >= MAX_SCHEDULE_TIMEOUT)
2270                 timeout = MAX_SCHEDULE_TIMEOUT-1;
2271         if (timeout < 1)
2272                 timeout = 1;
2273         mddev->bitmap_info.daemon_sleep = timeout;
2274         if (mddev->thread) {
2275                 /* if thread->timeout is MAX_SCHEDULE_TIMEOUT, then
2276                  * the bitmap is all clean and we don't need to
2277                  * adjust the timeout right now
2278                  */
2279                 if (mddev->thread->timeout < MAX_SCHEDULE_TIMEOUT) {
2280                         mddev->thread->timeout = timeout;
2281                         md_wakeup_thread(mddev->thread);
2282                 }
2283         }
2284         return len;
2285 }
2286
2287 static struct md_sysfs_entry bitmap_timeout =
2288 __ATTR(time_base, S_IRUGO|S_IWUSR, timeout_show, timeout_store);
2289
2290 static ssize_t
2291 backlog_show(struct mddev *mddev, char *page)
2292 {
2293         return sprintf(page, "%lu\n", mddev->bitmap_info.max_write_behind);
2294 }
2295
2296 static ssize_t
2297 backlog_store(struct mddev *mddev, const char *buf, size_t len)
2298 {
2299         unsigned long backlog;
2300         int rv = kstrtoul(buf, 10, &backlog);
2301         if (rv)
2302                 return rv;
2303         if (backlog > COUNTER_MAX)
2304                 return -EINVAL;
2305         mddev->bitmap_info.max_write_behind = backlog;
2306         return len;
2307 }
2308
2309 static struct md_sysfs_entry bitmap_backlog =
2310 __ATTR(backlog, S_IRUGO|S_IWUSR, backlog_show, backlog_store);
2311
2312 static ssize_t
2313 chunksize_show(struct mddev *mddev, char *page)
2314 {
2315         return sprintf(page, "%lu\n", mddev->bitmap_info.chunksize);
2316 }
2317
2318 static ssize_t
2319 chunksize_store(struct mddev *mddev, const char *buf, size_t len)
2320 {
2321         /* Can only be changed when no bitmap is active */
2322         int rv;
2323         unsigned long csize;
2324         if (mddev->bitmap)
2325                 return -EBUSY;
2326         rv = kstrtoul(buf, 10, &csize);
2327         if (rv)
2328                 return rv;
2329         if (csize < 512 ||
2330             !is_power_of_2(csize))
2331                 return -EINVAL;
2332         mddev->bitmap_info.chunksize = csize;
2333         return len;
2334 }
2335
2336 static struct md_sysfs_entry bitmap_chunksize =
2337 __ATTR(chunksize, S_IRUGO|S_IWUSR, chunksize_show, chunksize_store);
2338
2339 static ssize_t metadata_show(struct mddev *mddev, char *page)
2340 {
2341         if (mddev_is_clustered(mddev))
2342                 return sprintf(page, "clustered\n");
2343         return sprintf(page, "%s\n", (mddev->bitmap_info.external
2344                                       ? "external" : "internal"));
2345 }
2346
2347 static ssize_t metadata_store(struct mddev *mddev, const char *buf, size_t len)
2348 {
2349         if (mddev->bitmap ||
2350             mddev->bitmap_info.file ||
2351             mddev->bitmap_info.offset)
2352                 return -EBUSY;
2353         if (strncmp(buf, "external", 8) == 0)
2354                 mddev->bitmap_info.external = 1;
2355         else if ((strncmp(buf, "internal", 8) == 0) ||
2356                         (strncmp(buf, "clustered", 9) == 0))
2357                 mddev->bitmap_info.external = 0;
2358         else
2359                 return -EINVAL;
2360         return len;
2361 }
2362
2363 static struct md_sysfs_entry bitmap_metadata =
2364 __ATTR(metadata, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
2365
2366 static ssize_t can_clear_show(struct mddev *mddev, char *page)
2367 {
2368         int len;
2369         spin_lock(&mddev->lock);
2370         if (mddev->bitmap)
2371                 len = sprintf(page, "%s\n", (mddev->bitmap->need_sync ?
2372                                              "false" : "true"));
2373         else
2374                 len = sprintf(page, "\n");
2375         spin_unlock(&mddev->lock);
2376         return len;
2377 }
2378
2379 static ssize_t can_clear_store(struct mddev *mddev, const char *buf, size_t len)
2380 {
2381         if (mddev->bitmap == NULL)
2382                 return -ENOENT;
2383         if (strncmp(buf, "false", 5) == 0)
2384                 mddev->bitmap->need_sync = 1;
2385         else if (strncmp(buf, "true", 4) == 0) {
2386                 if (mddev->degraded)
2387                         return -EBUSY;
2388                 mddev->bitmap->need_sync = 0;
2389         } else
2390                 return -EINVAL;
2391         return len;
2392 }
2393
2394 static struct md_sysfs_entry bitmap_can_clear =
2395 __ATTR(can_clear, S_IRUGO|S_IWUSR, can_clear_show, can_clear_store);
2396
2397 static ssize_t
2398 behind_writes_used_show(struct mddev *mddev, char *page)
2399 {
2400         ssize_t ret;
2401         spin_lock(&mddev->lock);
2402         if (mddev->bitmap == NULL)
2403                 ret = sprintf(page, "0\n");
2404         else
2405                 ret = sprintf(page, "%lu\n",
2406                               mddev->bitmap->behind_writes_used);
2407         spin_unlock(&mddev->lock);
2408         return ret;
2409 }
2410
2411 static ssize_t
2412 behind_writes_used_reset(struct mddev *mddev, const char *buf, size_t len)
2413 {
2414         if (mddev->bitmap)
2415                 mddev->bitmap->behind_writes_used = 0;
2416         return len;
2417 }
2418
2419 static struct md_sysfs_entry max_backlog_used =
2420 __ATTR(max_backlog_used, S_IRUGO | S_IWUSR,
2421        behind_writes_used_show, behind_writes_used_reset);
2422
2423 static struct attribute *md_bitmap_attrs[] = {
2424         &bitmap_location.attr,
2425         &bitmap_space.attr,
2426         &bitmap_timeout.attr,
2427         &bitmap_backlog.attr,
2428         &bitmap_chunksize.attr,
2429         &bitmap_metadata.attr,
2430         &bitmap_can_clear.attr,
2431         &max_backlog_used.attr,
2432         NULL
2433 };
2434 struct attribute_group md_bitmap_group = {
2435         .name = "bitmap",
2436         .attrs = md_bitmap_attrs,
2437 };
2438