drivers/md/bitmap.c

   1 /*
   2  * bitmap.c two-level bitmap (C) Peter T. Breuer (ptb@ot.uc3m.es) 2003
   3  *
   4  * bitmap_create  - sets up the bitmap structure
   5  * bitmap_destroy - destroys the bitmap structure
   6  *
   7  * additions, Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.:
   8  * - added disk storage for bitmap
   9  * - changes to allow various bitmap chunk sizes
  10  */
  11
  12 /*
  13  * Still to do:
  14  *
  15  * flush after percent set rather than just time based. (maybe both).
  16  * wait if count gets too high, wake when it drops to half.
  17  */
  18
  19 #include <linux/blkdev.h>
  20 #include <linux/module.h>
  21 #include <linux/errno.h>
  22 #include <linux/slab.h>
  23 #include <linux/init.h>
  24 #include <linux/timer.h>
  25 #include <linux/sched.h>
  26 #include <linux/list.h>
  27 #include <linux/file.h>
  28 #include <linux/mount.h>
  29 #include <linux/buffer_head.h>
  30 #include "md.h"
  31 #include "bitmap.h"
  32
  33 /* debug macros */
  34
  35 #define DEBUG 0
  36
  37 #if DEBUG
  38 /* these are for debugging purposes only! */
  39
  40 /* define one and only one of these */
  41 #define INJECT_FAULTS_1 0 /* cause bitmap_alloc_page to fail always */
  42 #define INJECT_FAULTS_2 0 /* cause bitmap file to be kicked when first bit set*/
  43 #define INJECT_FAULTS_3 0 /* treat bitmap file as kicked at init time */
  44 #define INJECT_FAULTS_4 0 /* undef */
  45 #define INJECT_FAULTS_5 0 /* undef */
  46 #define INJECT_FAULTS_6 0
  47
  48 /* if these are defined, the driver will fail! debug only */
  49 #define INJECT_FATAL_FAULT_1 0 /* fail kmalloc, causing bitmap_create to fail */
  50 #define INJECT_FATAL_FAULT_2 0 /* undef */
  51 #define INJECT_FATAL_FAULT_3 0 /* undef */
  52 #endif
  53
  54 //#define DPRINTK PRINTK /* set this NULL to avoid verbose debug output */
  55 #define DPRINTK(x...) do { } while(0)
  56
  57 #ifndef PRINTK
  58 #  if DEBUG > 0
  59 #    define PRINTK(x...) printk(KERN_DEBUG x)
  60 #  else
  61 #    define PRINTK(x...)
  62 #  endif
  63 #endif
  64
  65 static inline char * bmname(struct bitmap *bitmap)
  66 {
  67         return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
  68 }
  69
  70
  71 /*
  72  * just a placeholder - calls kmalloc for bitmap pages
  73  */
  74 static unsigned char *bitmap_alloc_page(struct bitmap *bitmap)
  75 {
  76         unsigned char *page;
  77
  78 #ifdef INJECT_FAULTS_1
  79         page = NULL;
  80 #else
  81         page = kmalloc(PAGE_SIZE, GFP_NOIO);
  82 #endif
  83         if (!page)
  84                 printk("%s: bitmap_alloc_page FAILED\n", bmname(bitmap));
  85         else
  86                 PRINTK("%s: bitmap_alloc_page: allocated page at %p\n",
  87                         bmname(bitmap), page);
  88         return page;
  89 }
  90
  91 /*
  92  * for now just a placeholder -- just calls kfree for bitmap pages
  93  */
  94 static void bitmap_free_page(struct bitmap *bitmap, unsigned char *page)
  95 {
  96         PRINTK("%s: bitmap_free_page: free page %p\n", bmname(bitmap), page);
  97         kfree(page);
  98 }
  99
 100 /*
 101  * check a page and, if necessary, allocate it (or hijack it if the alloc fails)
 102  *
 103  * 1) check to see if this page is allocated, if it's not then try to alloc
 104  * 2) if the alloc fails, set the page's hijacked flag so we'll use the
 105  *    page pointer directly as a counter
 106  *
 107  * if we find our page, we increment the page's refcount so that it stays
 108  * allocated while we're using it
 109  */
 110 static int bitmap_checkpage(struct bitmap *bitmap, unsigned long page, int create)
 111 __releases(bitmap->lock)
 112 __acquires(bitmap->lock)
 113 {
 114         unsigned char *mappage;
 115
 116         if (page >= bitmap->pages) {
 117                 /* This can happen if bitmap_start_sync goes beyond
 118                  * End-of-device while looking for a whole page.
 119                  * It is harmless.
 120                  */
 121                 return -EINVAL;
 122         }
 123
 124
 125         if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
 126                 return 0;
 127
 128         if (bitmap->bp[page].map) /* page is already allocated, just return */
 129                 return 0;
 130
 131         if (!create)
 132                 return -ENOENT;
 133
 134         spin_unlock_irq(&bitmap->lock);
 135
 136         /* this page has not been allocated yet */
 137
 138         if ((mappage = bitmap_alloc_page(bitmap)) == NULL) {
 139                 PRINTK("%s: bitmap map page allocation failed, hijacking\n",
 140                         bmname(bitmap));
 141                 /* failed - set the hijacked flag so that we can use the
 142                  * pointer as a counter */
 143                 spin_lock_irq(&bitmap->lock);
 144                 if (!bitmap->bp[page].map)
 145                         bitmap->bp[page].hijacked = 1;
 146                 goto out;
 147         }
 148
 149         /* got a page */
 150
 151         spin_lock_irq(&bitmap->lock);
 152
 153         /* recheck the page */
 154
 155         if (bitmap->bp[page].map || bitmap->bp[page].hijacked) {
 156                 /* somebody beat us to getting the page */
 157                 bitmap_free_page(bitmap, mappage);
 158                 return 0;
 159         }
 160
 161         /* no page was in place and we have one, so install it */
 162
 163         memset(mappage, 0, PAGE_SIZE);
 164         bitmap->bp[page].map = mappage;
 165         bitmap->missing_pages--;
 166 out:
 167         return 0;
 168 }
 169
 170
 171 /* if page is completely empty, put it back on the free list, or dealloc it */
 172 /* if page was hijacked, unmark the flag so it might get alloced next time */
 173 /* Note: lock should be held when calling this */
 174 static void bitmap_checkfree(struct bitmap *bitmap, unsigned long page)
 175 {
 176         char *ptr;
 177
 178         if (bitmap->bp[page].count) /* page is still busy */
 179                 return;
 180
 181         /* page is no longer in use, it can be released */
 182
 183         if (bitmap->bp[page].hijacked) { /* page was hijacked, undo this now */
 184                 bitmap->bp[page].hijacked = 0;
 185                 bitmap->bp[page].map = NULL;
 186                 return;
 187         }
 188
 189         /* normal case, free the page */
 190
 191 #if 0
 192 /* actually ... let's not.  We will probably need the page again exactly when
 193  * memory is tight and we are flusing to disk
 194  */
 195         return;
 196 #else
 197         ptr = bitmap->bp[page].map;
 198         bitmap->bp[page].map = NULL;
 199         bitmap->missing_pages++;
 200         bitmap_free_page(bitmap, ptr);
 201         return;
 202 #endif
 203 }
 204
 205
 206 /*
 207  * bitmap file handling - read and write the bitmap file and its superblock
 208  */
 209
 210 /*
 211  * basic page I/O operations
 212  */
 213
 214 /* IO operations when bitmap is stored near all superblocks */
 215 static struct page *read_sb_page(mddev_t *mddev, loff_t offset,
 216                                  struct page *page,
 217                                  unsigned long index, int size)
 218 {
 219         /* choose a good rdev and read the page from there */
 220
 221         mdk_rdev_t *rdev;
 222         sector_t target;
 223
 224         if (!page)
 225                 page = alloc_page(GFP_KERNEL);
 226         if (!page)
 227                 return ERR_PTR(-ENOMEM);
 228
 229         list_for_each_entry(rdev, &mddev->disks, same_set) {
 230                 if (! test_bit(In_sync, &rdev->flags)
 231                     || test_bit(Faulty, &rdev->flags))
 232                         continue;
 233
 234                 target = rdev->sb_start + offset + index * (PAGE_SIZE/512);
 235
 236                 if (sync_page_io(rdev->bdev, target,
 237                                  roundup(size, bdev_logical_block_size(rdev->bdev)),
 238                                  page, READ)) {
 239                         page->index = index;
 240                         attach_page_buffers(page, NULL); /* so that free_buffer will
 241                                                           * quietly no-op */
 242                         return page;
 243                 }
 244         }
 245         return ERR_PTR(-EIO);
 246
 247 }
 248
 249 static mdk_rdev_t *next_active_rdev(mdk_rdev_t *rdev, mddev_t *mddev)
 250 {
 251         /* Iterate the disks of an mddev, using rcu to protect access to the
 252          * linked list, and raising the refcount of devices we return to ensure
 253          * they don't disappear while in use.
 254          * As devices are only added or removed when raid_disk is < 0 and
 255          * nr_pending is 0 and In_sync is clear, the entries we return will
 256          * still be in the same position on the list when we re-enter
 257          * list_for_each_continue_rcu.
 258          */
 259         struct list_head *pos;
 260         rcu_read_lock();
 261         if (rdev == NULL)
 262                 /* start at the beginning */
 263                 pos = &mddev->disks;
 264         else {
 265                 /* release the previous rdev and start from there. */
 266                 rdev_dec_pending(rdev, mddev);
 267                 pos = &rdev->same_set;
 268         }
 269         list_for_each_continue_rcu(pos, &mddev->disks) {
 270                 rdev = list_entry(pos, mdk_rdev_t, same_set);
 271                 if (rdev->raid_disk >= 0 &&
 272                     !test_bit(Faulty, &rdev->flags)) {
 273                         /* this is a usable devices */
 274                         atomic_inc(&rdev->nr_pending);
 275                         rcu_read_unlock();
 276                         return rdev;
 277                 }
 278         }
 279         rcu_read_unlock();
 280         return NULL;
 281 }
 282
 283 static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
 284 {
 285         mdk_rdev_t *rdev = NULL;
 286         mddev_t *mddev = bitmap->mddev;
 287
 288         while ((rdev = next_active_rdev(rdev, mddev)) != NULL) {
 289                         int size = PAGE_SIZE;
 290                         loff_t offset = mddev->bitmap_info.offset;
 291                         if (page->index == bitmap->file_pages-1)
 292                                 size = roundup(bitmap->last_page_size,
 293                                                bdev_logical_block_size(rdev->bdev));
 294                         /* Just make sure we aren't corrupting data or
 295                          * metadata
 296                          */
 297                         if (mddev->external) {
 298                                 /* Bitmap could be anywhere. */
 299                                 if (rdev->sb_start + offset + (page->index *(PAGE_SIZE/512)) >
 300                                     rdev->data_offset &&
 301                                     rdev->sb_start + offset <
 302                                     rdev->data_offset + mddev->dev_sectors +
 303                                     (PAGE_SIZE/512))
 304                                         goto bad_alignment;
 305                         } else if (offset < 0) {
 306                                 /* DATA  BITMAP METADATA  */
 307                                 if (offset
 308                                     + (long)(page->index * (PAGE_SIZE/512))
 309                                     + size/512 > 0)
 310                                         /* bitmap runs in to metadata */
 311                                         goto bad_alignment;
 312                                 if (rdev->data_offset + mddev->dev_sectors
 313                                     > rdev->sb_start + offset)
 314                                         /* data runs in to bitmap */
 315                                         goto bad_alignment;
 316                         } else if (rdev->sb_start < rdev->data_offset) {
 317                                 /* METADATA BITMAP DATA */
 318                                 if (rdev->sb_start
 319                                     + offset
 320                                     + page->index*(PAGE_SIZE/512) + size/512
 321                                     > rdev->data_offset)
 322                                         /* bitmap runs in to data */
 323                                         goto bad_alignment;
 324                         } else {
 325                                 /* DATA METADATA BITMAP - no problems */
 326                         }
 327                         md_super_write(mddev, rdev,
 328                                        rdev->sb_start + offset
 329                                        + page->index * (PAGE_SIZE/512),
 330                                        size,
 331                                        page);
 332         }
 333
 334         if (wait)
 335                 md_super_wait(mddev);
 336         return 0;
 337
 338  bad_alignment:
 339         return -EINVAL;
 340 }
 341
 342 static void bitmap_file_kick(struct bitmap *bitmap);
 343 /*
 344  * write out a page to a file
 345  */
 346 static void write_page(struct bitmap *bitmap, struct page *page, int wait)
 347 {
 348         struct buffer_head *bh;
 349
 350         if (bitmap->file == NULL) {
 351                 switch (write_sb_page(bitmap, page, wait)) {
 352                 case -EINVAL:
 353                         bitmap->flags |= BITMAP_WRITE_ERROR;
 354                 }
 355         } else {
 356
 357                 bh = page_buffers(page);
 358
 359                 while (bh && bh->b_blocknr) {
 360                         atomic_inc(&bitmap->pending_writes);
 361                         set_buffer_locked(bh);
 362                         set_buffer_mapped(bh);
 363                         submit_bh(WRITE, bh);
 364                         bh = bh->b_this_page;
 365                 }
 366
 367                 if (wait) {
 368                         wait_event(bitmap->write_wait,
 369                                    atomic_read(&bitmap->pending_writes)==0);
 370                 }
 371         }
 372         if (bitmap->flags & BITMAP_WRITE_ERROR)
 373                 bitmap_file_kick(bitmap);
 374 }
 375
 376 static void end_bitmap_write(struct buffer_head *bh, int uptodate)
 377 {
 378         struct bitmap *bitmap = bh->b_private;
 379         unsigned long flags;
 380
 381         if (!uptodate) {
 382                 spin_lock_irqsave(&bitmap->lock, flags);
 383                 bitmap->flags |= BITMAP_WRITE_ERROR;
 384                 spin_unlock_irqrestore(&bitmap->lock, flags);
 385         }
 386         if (atomic_dec_and_test(&bitmap->pending_writes))
 387                 wake_up(&bitmap->write_wait);
 388 }
 389
 390 /* copied from buffer.c */
 391 static void
 392 __clear_page_buffers(struct page *page)
 393 {
 394         ClearPagePrivate(page);
 395         set_page_private(page, 0);
 396         page_cache_release(page);
 397 }
 398 static void free_buffers(struct page *page)
 399 {
 400         struct buffer_head *bh = page_buffers(page);
 401
 402         while (bh) {
 403                 struct buffer_head *next = bh->b_this_page;
 404                 free_buffer_head(bh);
 405                 bh = next;
 406         }
 407         __clear_page_buffers(page);
 408         put_page(page);
 409 }
 410
 411 /* read a page from a file.
 412  * We both read the page, and attach buffers to the page to record the
 413  * address of each block (using bmap).  These addresses will be used
 414  * to write the block later, completely bypassing the filesystem.
 415  * This usage is similar to how swap files are handled, and allows us
 416  * to write to a file with no concerns of memory allocation failing.
 417  */
 418 static struct page *read_page(struct file *file, unsigned long index,
 419                               struct bitmap *bitmap,
 420                               unsigned long count)
 421 {
 422         struct page *page = NULL;
 423         struct inode *inode = file->f_path.dentry->d_inode;
 424         struct buffer_head *bh;
 425         sector_t block;
 426
 427         PRINTK("read bitmap file (%dB @ %Lu)\n", (int)PAGE_SIZE,
 428                         (unsigned long long)index << PAGE_SHIFT);
 429
 430         page = alloc_page(GFP_KERNEL);
 431         if (!page)
 432                 page = ERR_PTR(-ENOMEM);
 433         if (IS_ERR(page))
 434                 goto out;
 435
 436         bh = alloc_page_buffers(page, 1<<inode->i_blkbits, 0);
 437         if (!bh) {
 438                 put_page(page);
 439                 page = ERR_PTR(-ENOMEM);
 440                 goto out;
 441         }
 442         attach_page_buffers(page, bh);
 443         block = index << (PAGE_SHIFT - inode->i_blkbits);
 444         while (bh) {
 445                 if (count == 0)
 446                         bh->b_blocknr = 0;
 447                 else {
 448                         bh->b_blocknr = bmap(inode, block);
 449                         if (bh->b_blocknr == 0) {
 450                                 /* Cannot use this file! */
 451                                 free_buffers(page);
 452                                 page = ERR_PTR(-EINVAL);
 453                                 goto out;
 454                         }
 455                         bh->b_bdev = inode->i_sb->s_bdev;
 456                         if (count < (1<<inode->i_blkbits))
 457                                 count = 0;
 458                         else
 459                                 count -= (1<<inode->i_blkbits);
 460
 461                         bh->b_end_io = end_bitmap_write;
 462                         bh->b_private = bitmap;
 463                         atomic_inc(&bitmap->pending_writes);
 464                         set_buffer_locked(bh);
 465                         set_buffer_mapped(bh);
 466                         submit_bh(READ, bh);
 467                 }
 468                 block++;
 469                 bh = bh->b_this_page;
 470         }
 471         page->index = index;
 472
 473         wait_event(bitmap->write_wait,
 474                    atomic_read(&bitmap->pending_writes)==0);
 475         if (bitmap->flags & BITMAP_WRITE_ERROR) {
 476                 free_buffers(page);
 477                 page = ERR_PTR(-EIO);
 478         }
 479 out:
 480         if (IS_ERR(page))
 481                 printk(KERN_ALERT "md: bitmap read error: (%dB @ %Lu): %ld\n",
 482                         (int)PAGE_SIZE,
 483                         (unsigned long long)index << PAGE_SHIFT,
 484                         PTR_ERR(page));
 485         return page;
 486 }
 487
 488 /*
 489  * bitmap file superblock operations
 490  */
 491
 492 /* update the event counter and sync the superblock to disk */
 493 void bitmap_update_sb(struct bitmap *bitmap)
 494 {
 495         bitmap_super_t *sb;
 496         unsigned long flags;
 497
 498         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
 499                 return;
 500         if (bitmap->mddev->bitmap_info.external)
 501                 return;
 502         spin_lock_irqsave(&bitmap->lock, flags);
 503         if (!bitmap->sb_page) { /* no superblock */
 504                 spin_unlock_irqrestore(&bitmap->lock, flags);
 505                 return;
 506         }
 507         spin_unlock_irqrestore(&bitmap->lock, flags);
 508         sb = kmap_atomic(bitmap->sb_page, KM_USER0);
 509         sb->events = cpu_to_le64(bitmap->mddev->events);
 510         if (bitmap->mddev->events < bitmap->events_cleared) {
 511                 /* rocking back to read-only */
 512                 bitmap->events_cleared = bitmap->mddev->events;
 513                 sb->events_cleared = cpu_to_le64(bitmap->events_cleared);
 514         }
 515         /* Just in case these have been changed via sysfs: */
 516         sb->daemon_sleep = cpu_to_le32(bitmap->mddev->bitmap_info.daemon_sleep/HZ);
 517         sb->write_behind = cpu_to_le32(bitmap->mddev->bitmap_info.max_write_behind);
 518         kunmap_atomic(sb, KM_USER0);
 519         write_page(bitmap, bitmap->sb_page, 1);
 520 }
 521
 522 /* print out the bitmap file superblock */
 523 void bitmap_print_sb(struct bitmap *bitmap)
 524 {
 525         bitmap_super_t *sb;
 526
 527         if (!bitmap || !bitmap->sb_page)
 528                 return;
 529         sb = kmap_atomic(bitmap->sb_page, KM_USER0);
 530         printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
 531         printk(KERN_DEBUG "         magic: %08x\n", le32_to_cpu(sb->magic));
 532         printk(KERN_DEBUG "       version: %d\n", le32_to_cpu(sb->version));
 533         printk(KERN_DEBUG "          uuid: %08x.%08x.%08x.%08x\n",
 534                                         *(__u32 *)(sb->uuid+0),
 535                                         *(__u32 *)(sb->uuid+4),
 536                                         *(__u32 *)(sb->uuid+8),
 537                                         *(__u32 *)(sb->uuid+12));
 538         printk(KERN_DEBUG "        events: %llu\n",
 539                         (unsigned long long) le64_to_cpu(sb->events));
 540         printk(KERN_DEBUG "events cleared: %llu\n",
 541                         (unsigned long long) le64_to_cpu(sb->events_cleared));
 542         printk(KERN_DEBUG "         state: %08x\n", le32_to_cpu(sb->state));
 543         printk(KERN_DEBUG "     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
 544         printk(KERN_DEBUG "  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
 545         printk(KERN_DEBUG "     sync size: %llu KB\n",
 546                         (unsigned long long)le64_to_cpu(sb->sync_size)/2);
 547         printk(KERN_DEBUG "max write behind: %d\n", le32_to_cpu(sb->write_behind));
 548         kunmap_atomic(sb, KM_USER0);
 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 err = -EINVAL;
 559
 560         /* page 0 is the superblock, read it... */
 561         if (bitmap->file) {
 562                 loff_t isize = i_size_read(bitmap->file->f_mapping->host);
 563                 int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
 564
 565                 bitmap->sb_page = read_page(bitmap->file, 0, bitmap, bytes);
 566         } else {
 567                 bitmap->sb_page = read_sb_page(bitmap->mddev,
 568                                                bitmap->mddev->bitmap_info.offset,
 569                                                NULL,
 570                                                0, sizeof(bitmap_super_t));
 571         }
 572         if (IS_ERR(bitmap->sb_page)) {
 573                 err = PTR_ERR(bitmap->sb_page);
 574                 bitmap->sb_page = NULL;
 575                 return err;
 576         }
 577
 578         sb = kmap_atomic(bitmap->sb_page, KM_USER0);
 579
 580         chunksize = le32_to_cpu(sb->chunksize);
 581         daemon_sleep = le32_to_cpu(sb->daemon_sleep) * HZ;
 582         write_behind = le32_to_cpu(sb->write_behind);
 583
 584         /* verify that the bitmap-specific fields are valid */
 585         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
 586                 reason = "bad magic";
 587         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
 588                  le32_to_cpu(sb->version) > BITMAP_MAJOR_HI)
 589                 reason = "unrecognized superblock version";
 590         else if (chunksize < 512)
 591                 reason = "bitmap chunksize too small";
 592         else if ((1 << ffz(~chunksize)) != chunksize)
 593                 reason = "bitmap chunksize not a power of 2";
 594         else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT)
 595                 reason = "daemon sleep period out of range";
 596         else if (write_behind > COUNTER_MAX)
 597                 reason = "write-behind limit out of range (0 - 16383)";
 598         if (reason) {
 599                 printk(KERN_INFO "%s: invalid bitmap file superblock: %s\n",
 600                         bmname(bitmap), reason);
 601                 goto out;
 602         }
 603
 604         /* keep the array size field of the bitmap superblock up to date */
 605         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 606
 607         if (!bitmap->mddev->persistent)
 608                 goto success;
 609
 610         /*
 611          * if we have a persistent array superblock, compare the
 612          * bitmap's UUID and event counter to the mddev's
 613          */
 614         if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
 615                 printk(KERN_INFO "%s: bitmap superblock UUID mismatch\n",
 616                         bmname(bitmap));
 617                 goto out;
 618         }
 619         events = le64_to_cpu(sb->events);
 620         if (events < bitmap->mddev->events) {
 621                 printk(KERN_INFO "%s: bitmap file is out of date (%llu < %llu) "
 622                         "-- forcing full recovery\n", bmname(bitmap), events,
 623                         (unsigned long long) bitmap->mddev->events);
 624                 sb->state |= cpu_to_le32(BITMAP_STALE);
 625         }
 626 success:
 627         /* assign fields using values from superblock */
 628         bitmap->mddev->bitmap_info.chunksize = chunksize;
 629         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 630         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 631         bitmap->flags |= le32_to_cpu(sb->state);
 632         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
 633                 bitmap->flags |= BITMAP_HOSTENDIAN;
 634         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
 635         if (sb->state & cpu_to_le32(BITMAP_STALE))
 636                 bitmap->events_cleared = bitmap->mddev->events;
 637         err = 0;
 638 out:
 639         kunmap_atomic(sb, KM_USER0);
 640         if (err)
 641                 bitmap_print_sb(bitmap);
 642         return err;
 643 }
 644
 645 enum bitmap_mask_op {
 646         MASK_SET,
 647         MASK_UNSET
 648 };
 649
 650 /* record the state of the bitmap in the superblock.  Return the old value */
 651 static int bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
 652                              enum bitmap_mask_op op)
 653 {
 654         bitmap_super_t *sb;
 655         unsigned long flags;
 656         int old;
 657
 658         spin_lock_irqsave(&bitmap->lock, flags);
 659         if (!bitmap->sb_page) { /* can't set the state */
 660                 spin_unlock_irqrestore(&bitmap->lock, flags);
 661                 return 0;
 662         }
 663         spin_unlock_irqrestore(&bitmap->lock, flags);
 664         sb = kmap_atomic(bitmap->sb_page, KM_USER0);
 665         old = le32_to_cpu(sb->state) & bits;
 666         switch (op) {
 667                 case MASK_SET: sb->state |= cpu_to_le32(bits);
 668                                 break;
 669                 case MASK_UNSET: sb->state &= cpu_to_le32(~bits);
 670                                 break;
 671                 default: BUG();
 672         }
 673         kunmap_atomic(sb, KM_USER0);
 674         return old;
 675 }
 676
 677 /*
 678  * general bitmap file operations
 679  */
 680
 681 /*
 682  * on-disk bitmap:
 683  *
 684  * Use one bit per "chunk" (block set). We do the disk I/O on the bitmap
 685  * file a page at a time. There's a superblock at the start of the file.
 686  */
 687 /* calculate the index of the page that contains this bit */
 688 static inline unsigned long file_page_index(struct bitmap *bitmap, unsigned long chunk)
 689 {
 690         if (!bitmap->mddev->bitmap_info.external)
 691                 chunk += sizeof(bitmap_super_t) << 3;
 692         return chunk >> PAGE_BIT_SHIFT;
 693 }
 694
 695 /* calculate the (bit) offset of this bit within a page */
 696 static inline unsigned long file_page_offset(struct bitmap *bitmap, unsigned long chunk)
 697 {
 698         if (!bitmap->mddev->bitmap_info.external)
 699                 chunk += sizeof(bitmap_super_t) << 3;
 700         return chunk & (PAGE_BITS - 1);
 701 }
 702
 703 /*
 704  * return a pointer to the page in the filemap that contains the given bit
 705  *
 706  * this lookup is complicated by the fact that the bitmap sb might be exactly
 707  * 1 page (e.g., x86) or less than 1 page -- so the bitmap might start on page
 708  * 0 or page 1
 709  */
 710 static inline struct page *filemap_get_page(struct bitmap *bitmap,
 711                                         unsigned long chunk)
 712 {
 713         if (file_page_index(bitmap, chunk) >= bitmap->file_pages) return NULL;
 714         return bitmap->filemap[file_page_index(bitmap, chunk)
 715                                - file_page_index(bitmap, 0)];
 716 }
 717
 718
 719 static void bitmap_file_unmap(struct bitmap *bitmap)
 720 {
 721         struct page **map, *sb_page;
 722         unsigned long *attr;
 723         int pages;
 724         unsigned long flags;
 725
 726         spin_lock_irqsave(&bitmap->lock, flags);
 727         map = bitmap->filemap;
 728         bitmap->filemap = NULL;
 729         attr = bitmap->filemap_attr;
 730         bitmap->filemap_attr = NULL;
 731         pages = bitmap->file_pages;
 732         bitmap->file_pages = 0;
 733         sb_page = bitmap->sb_page;
 734         bitmap->sb_page = NULL;
 735         spin_unlock_irqrestore(&bitmap->lock, flags);
 736
 737         while (pages--)
 738                 if (map[pages] != sb_page) /* 0 is sb_page, release it below */
 739                         free_buffers(map[pages]);
 740         kfree(map);
 741         kfree(attr);
 742
 743         if (sb_page)
 744                 free_buffers(sb_page);
 745 }
 746
 747 static void bitmap_file_put(struct bitmap *bitmap)
 748 {
 749         struct file *file;
 750         unsigned long flags;
 751
 752         spin_lock_irqsave(&bitmap->lock, flags);
 753         file = bitmap->file;
 754         bitmap->file = NULL;
 755         spin_unlock_irqrestore(&bitmap->lock, flags);
 756
 757         if (file)
 758                 wait_event(bitmap->write_wait,
 759                            atomic_read(&bitmap->pending_writes)==0);
 760         bitmap_file_unmap(bitmap);
 761
 762         if (file) {
 763                 struct inode *inode = file->f_path.dentry->d_inode;
 764                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
 765                 fput(file);
 766         }
 767 }
 768
 769
 770 /*
 771  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
 772  * then it is no longer reliable, so we stop using it and we mark the file
 773  * as failed in the superblock
 774  */
 775 static void bitmap_file_kick(struct bitmap *bitmap)
 776 {
 777         char *path, *ptr = NULL;
 778
 779         if (bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET) == 0) {
 780                 bitmap_update_sb(bitmap);
 781
 782                 if (bitmap->file) {
 783                         path = kmalloc(PAGE_SIZE, GFP_KERNEL);
 784                         if (path)
 785                                 ptr = d_path(&bitmap->file->f_path, path,
 786                                              PAGE_SIZE);
 787
 788
 789                         printk(KERN_ALERT
 790                               "%s: kicking failed bitmap file %s from array!\n",
 791                               bmname(bitmap), IS_ERR(ptr) ? "" : ptr);
 792
 793                         kfree(path);
 794                 } else
 795                         printk(KERN_ALERT
 796                                "%s: disabling internal bitmap due to errors\n",
 797                                bmname(bitmap));
 798         }
 799
 800         bitmap_file_put(bitmap);
 801
 802         return;
 803 }
 804
 805 enum bitmap_page_attr {
 806         BITMAP_PAGE_DIRTY = 0, // there are set bits that need to be synced
 807         BITMAP_PAGE_CLEAN = 1, // there are bits that might need to be cleared
 808         BITMAP_PAGE_NEEDWRITE=2, // there are cleared bits that need to be synced
 809 };
 810
 811 static inline void set_page_attr(struct bitmap *bitmap, struct page *page,
 812                                 enum bitmap_page_attr attr)
 813 {
 814         __set_bit((page->index<<2) + attr, bitmap->filemap_attr);
 815 }
 816
 817 static inline void clear_page_attr(struct bitmap *bitmap, struct page *page,
 818                                 enum bitmap_page_attr attr)
 819 {
 820         __clear_bit((page->index<<2) + attr, bitmap->filemap_attr);
 821 }
 822
 823 static inline unsigned long test_page_attr(struct bitmap *bitmap, struct page *page,
 824                                            enum bitmap_page_attr attr)
 825 {
 826         return test_bit((page->index<<2) + attr, bitmap->filemap_attr);
 827 }
 828
 829 /*
 830  * bitmap_file_set_bit -- called before performing a write to the md device
 831  * to set (and eventually sync) a particular bit in the bitmap file
 832  *
 833  * we set the bit immediately, then we record the page number so that
 834  * when an unplug occurs, we can flush the dirty pages out to disk
 835  */
 836 static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 837 {
 838         unsigned long bit;
 839         struct page *page;
 840         void *kaddr;
 841         unsigned long chunk = block >> CHUNK_BLOCK_SHIFT(bitmap);
 842
 843         if (!bitmap->filemap) {
 844                 return;
 845         }
 846
 847         page = filemap_get_page(bitmap, chunk);
 848         if (!page) return;
 849         bit = file_page_offset(bitmap, chunk);
 850
 851         /* set the bit */
 852         kaddr = kmap_atomic(page, KM_USER0);
 853         if (bitmap->flags & BITMAP_HOSTENDIAN)
 854                 set_bit(bit, kaddr);
 855         else
 856                 ext2_set_bit(bit, kaddr);
 857         kunmap_atomic(kaddr, KM_USER0);
 858         PRINTK("set file bit %lu page %lu\n", bit, page->index);
 859
 860         /* record page number so it gets flushed to disk when unplug occurs */
 861         set_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 862
 863 }
 864
 865 /* this gets called when the md device is ready to unplug its underlying
 866  * (slave) device queues -- before we let any writes go down, we need to
 867  * sync the dirty pages of the bitmap file to disk */
 868 void bitmap_unplug(struct bitmap *bitmap)
 869 {
 870         unsigned long i, flags;
 871         int dirty, need_write;
 872         struct page *page;
 873         int wait = 0;
 874
 875         if (!bitmap)
 876                 return;
 877
 878         /* look at each page to see if there are any set bits that need to be
 879          * flushed out to disk */
 880         for (i = 0; i < bitmap->file_pages; i++) {
 881                 spin_lock_irqsave(&bitmap->lock, flags);
 882                 if (!bitmap->filemap) {
 883                         spin_unlock_irqrestore(&bitmap->lock, flags);
 884                         return;
 885                 }
 886                 page = bitmap->filemap[i];
 887                 dirty = test_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 888                 need_write = test_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 889                 clear_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 890                 clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 891                 if (dirty)
 892                         wait = 1;
 893                 spin_unlock_irqrestore(&bitmap->lock, flags);
 894
 895                 if (dirty | need_write)
 896                         write_page(bitmap, page, 0);
 897         }
 898         if (wait) { /* if any writes were performed, we need to wait on them */
 899                 if (bitmap->file)
 900                         wait_event(bitmap->write_wait,
 901                                    atomic_read(&bitmap->pending_writes)==0);
 902                 else
 903                         md_super_wait(bitmap->mddev);
 904         }
 905         if (bitmap->flags & BITMAP_WRITE_ERROR)
 906                 bitmap_file_kick(bitmap);
 907 }
 908
 909 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
 910 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
 911  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
 912  * memory mapping of the bitmap file
 913  * Special cases:
 914  *   if there's no bitmap file, or if the bitmap file had been
 915  *   previously kicked from the array, we mark all the bits as
 916  *   1's in order to cause a full resync.
 917  *
 918  * We ignore all bits for sectors that end earlier than 'start'.
 919  * This is used when reading an out-of-date bitmap...
 920  */
 921 static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
 922 {
 923         unsigned long i, chunks, index, oldindex, bit;
 924         struct page *page = NULL, *oldpage = NULL;
 925         unsigned long num_pages, bit_cnt = 0;
 926         struct file *file;
 927         unsigned long bytes, offset;
 928         int outofdate;
 929         int ret = -ENOSPC;
 930         void *paddr;
 931
 932         chunks = bitmap->chunks;
 933         file = bitmap->file;
 934
 935         BUG_ON(!file && !bitmap->mddev->bitmap_info.offset);
 936
 937 #ifdef INJECT_FAULTS_3
 938         outofdate = 1;
 939 #else
 940         outofdate = bitmap->flags & BITMAP_STALE;
 941 #endif
 942         if (outofdate)
 943                 printk(KERN_INFO "%s: bitmap file is out of date, doing full "
 944                         "recovery\n", bmname(bitmap));
 945
 946         bytes = (chunks + 7) / 8;
 947         if (!bitmap->mddev->bitmap_info.external)
 948                 bytes += sizeof(bitmap_super_t);
 949
 950
 951         num_pages = (bytes + PAGE_SIZE - 1) / PAGE_SIZE;
 952
 953         if (file && i_size_read(file->f_mapping->host) < bytes) {
 954                 printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
 955                         bmname(bitmap),
 956                         (unsigned long) i_size_read(file->f_mapping->host),
 957                         bytes);
 958                 goto err;
 959         }
 960
 961         ret = -ENOMEM;
 962
 963         bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
 964         if (!bitmap->filemap)
 965                 goto err;
 966
 967         /* We need 4 bits per page, rounded up to a multiple of sizeof(unsigned long) */
 968         bitmap->filemap_attr = kzalloc(
 969                 roundup( DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
 970                 GFP_KERNEL);
 971         if (!bitmap->filemap_attr)
 972                 goto err;
 973
 974         oldindex = ~0L;
 975
 976         for (i = 0; i < chunks; i++) {
 977                 int b;
 978                 index = file_page_index(bitmap, i);
 979                 bit = file_page_offset(bitmap, i);
 980                 if (index != oldindex) { /* this is a new page, read it in */
 981                         int count;
 982                         /* unmap the old page, we're done with it */
 983                         if (index == num_pages-1)
 984                                 count = bytes - index * PAGE_SIZE;
 985                         else
 986                                 count = PAGE_SIZE;
 987                         if (index == 0 && bitmap->sb_page) {
 988                                 /*
 989                                  * if we're here then the superblock page
 990                                  * contains some bits (PAGE_SIZE != sizeof sb)
 991                                  * we've already read it in, so just use it
 992                                  */
 993                                 page = bitmap->sb_page;
 994                                 offset = sizeof(bitmap_super_t);
 995                                 if (!file)
 996                                         read_sb_page(bitmap->mddev,
 997                                                      bitmap->mddev->bitmap_info.offset,
 998                                                      page,
 999                                                      index, count);
1000                         } else if (file) {
1001                                 page = read_page(file, index, bitmap, count);
1002                                 offset = 0;
1003                         } else {
1004                                 page = read_sb_page(bitmap->mddev,
1005                                                     bitmap->mddev->bitmap_info.offset,
1006                                                     NULL,
1007                                                     index, count);
1008                                 offset = 0;
1009                         }
1010                         if (IS_ERR(page)) { /* read error */
1011                                 ret = PTR_ERR(page);
1012                                 goto err;
1013                         }
1014
1015                         oldindex = index;
1016                         oldpage = page;
1017
1018                         bitmap->filemap[bitmap->file_pages++] = page;
1019                         bitmap->last_page_size = count;
1020
1021                         if (outofdate) {
1022                                 /*
1023                                  * if bitmap is out of date, dirty the
1024                                  * whole page and write it out
1025                                  */
1026                                 paddr = kmap_atomic(page, KM_USER0);
1027                                 memset(paddr + offset, 0xff,
1028                                        PAGE_SIZE - offset);
1029                                 kunmap_atomic(paddr, KM_USER0);
1030                                 write_page(bitmap, page, 1);
1031
1032                                 ret = -EIO;
1033                                 if (bitmap->flags & BITMAP_WRITE_ERROR)
1034                                         goto err;
1035                         }
1036                 }
1037                 paddr = kmap_atomic(page, KM_USER0);
1038                 if (bitmap->flags & BITMAP_HOSTENDIAN)
1039                         b = test_bit(bit, paddr);
1040                 else
1041                         b = ext2_test_bit(bit, paddr);
1042                 kunmap_atomic(paddr, KM_USER0);
1043                 if (b) {
1044                         /* if the disk bit is set, set the memory bit */
1045                         int needed = ((sector_t)(i+1) << (CHUNK_BLOCK_SHIFT(bitmap))
1046                                       >= start);
1047                         bitmap_set_memory_bits(bitmap,
1048                                                (sector_t)i << CHUNK_BLOCK_SHIFT(bitmap),
1049                                                needed);
1050                         bit_cnt++;
1051                         set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1052                 }
1053         }
1054
1055         /* everything went OK */
1056         ret = 0;
1057         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_UNSET);
1058
1059         if (bit_cnt) { /* Kick recovery if any bits were set */
1060                 set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
1061                 md_wakeup_thread(bitmap->mddev->thread);
1062         }
1063
1064         printk(KERN_INFO "%s: bitmap initialized from disk: "
1065                 "read %lu/%lu pages, set %lu bits\n",
1066                 bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt);
1067
1068         return 0;
1069
1070  err:
1071         printk(KERN_INFO "%s: bitmap initialisation failed: %d\n",
1072                bmname(bitmap), ret);
1073         return ret;
1074 }
1075
1076 void bitmap_write_all(struct bitmap *bitmap)
1077 {
1078         /* We don't actually write all bitmap blocks here,
1079          * just flag them as needing to be written
1080          */
1081         int i;
1082
1083         for (i=0; i < bitmap->file_pages; i++)
1084                 set_page_attr(bitmap, bitmap->filemap[i],
1085                               BITMAP_PAGE_NEEDWRITE);
1086 }
1087
1088
1089 static void bitmap_count_page(struct bitmap *bitmap, sector_t offset, int inc)
1090 {
1091         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1092         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1093         bitmap->bp[page].count += inc;
1094 /*
1095         if (page == 0) printk("count page 0, offset %llu: %d gives %d\n",
1096                               (unsigned long long)offset, inc, bitmap->bp[page].count);
1097 */
1098         bitmap_checkfree(bitmap, page);
1099 }
1100 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1101                                             sector_t offset, int *blocks,
1102                                             int create);
1103
1104 /*
1105  * bitmap daemon -- periodically wakes up to clean bits and flush pages
1106  *                      out to disk
1107  */
1108
1109 void bitmap_daemon_work(mddev_t *mddev)
1110 {
1111         struct bitmap *bitmap;
1112         unsigned long j;
1113         unsigned long flags;
1114         struct page *page = NULL, *lastpage = NULL;
1115         int blocks;
1116         void *paddr;
1117
1118         /* Use a mutex to guard daemon_work against
1119          * bitmap_destroy.
1120          */
1121         mutex_lock(&mddev->bitmap_info.mutex);
1122         bitmap = mddev->bitmap;
1123         if (bitmap == NULL) {
1124                 mutex_unlock(&mddev->bitmap_info.mutex);
1125                 return;
1126         }
1127         if (time_before(jiffies, bitmap->daemon_lastrun
1128                         + bitmap->mddev->bitmap_info.daemon_sleep))
1129                 goto done;
1130
1131         bitmap->daemon_lastrun = jiffies;
1132         if (bitmap->allclean) {
1133                 bitmap->mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1134                 goto done;
1135         }
1136         bitmap->allclean = 1;
1137
1138         spin_lock_irqsave(&bitmap->lock, flags);
1139         for (j = 0; j < bitmap->chunks; j++) {
1140                 bitmap_counter_t *bmc;
1141                 if (!bitmap->filemap)
1142                         /* error or shutdown */
1143                         break;
1144
1145                 page = filemap_get_page(bitmap, j);
1146
1147                 if (page != lastpage) {
1148                         /* skip this page unless it's marked as needing cleaning */
1149                         if (!test_page_attr(bitmap, page, BITMAP_PAGE_CLEAN)) {
1150                                 int need_write = test_page_attr(bitmap, page,
1151                                                                 BITMAP_PAGE_NEEDWRITE);
1152                                 if (need_write)
1153                                         clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
1154
1155                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1156                                 if (need_write) {
1157                                         write_page(bitmap, page, 0);
1158                                         bitmap->allclean = 0;
1159                                 }
1160                                 spin_lock_irqsave(&bitmap->lock, flags);
1161                                 j |= (PAGE_BITS - 1);
1162                                 continue;
1163                         }
1164
1165                         /* grab the new page, sync and release the old */
1166                         if (lastpage != NULL) {
1167                                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1168                                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1169                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1170                                         write_page(bitmap, lastpage, 0);
1171                                 } else {
1172                                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1173                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1174                                 }
1175                         } else
1176                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1177                         lastpage = page;
1178
1179                         /* We are possibly going to clear some bits, so make
1180                          * sure that events_cleared is up-to-date.
1181                          */
1182                         if (bitmap->need_sync &&
1183                             bitmap->mddev->bitmap_info.external == 0) {
1184                                 bitmap_super_t *sb;
1185                                 bitmap->need_sync = 0;
1186                                 sb = kmap_atomic(bitmap->sb_page, KM_USER0);
1187                                 sb->events_cleared =
1188                                         cpu_to_le64(bitmap->events_cleared);
1189                                 kunmap_atomic(sb, KM_USER0);
1190                                 write_page(bitmap, bitmap->sb_page, 1);
1191                         }
1192                         spin_lock_irqsave(&bitmap->lock, flags);
1193                         if (!bitmap->need_sync)
1194                                 clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1195                 }
1196                 bmc = bitmap_get_counter(bitmap,
1197                                          (sector_t)j << CHUNK_BLOCK_SHIFT(bitmap),
1198                                          &blocks, 0);
1199                 if (bmc) {
1200 /*
1201   if (j < 100) printk("bitmap: j=%lu, *bmc = 0x%x\n", j, *bmc);
1202 */
1203                         if (*bmc)
1204                                 bitmap->allclean = 0;
1205
1206                         if (*bmc == 2) {
1207                                 *bmc=1; /* maybe clear the bit next time */
1208                                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1209                         } else if (*bmc == 1 && !bitmap->need_sync) {
1210                                 /* we can clear the bit */
1211                                 *bmc = 0;
1212                                 bitmap_count_page(bitmap,
1213                                                   (sector_t)j << CHUNK_BLOCK_SHIFT(bitmap),
1214                                                   -1);
1215
1216                                 /* clear the bit */
1217                                 paddr = kmap_atomic(page, KM_USER0);
1218                                 if (bitmap->flags & BITMAP_HOSTENDIAN)
1219                                         clear_bit(file_page_offset(bitmap, j),
1220                                                   paddr);
1221                                 else
1222                                         ext2_clear_bit(file_page_offset(bitmap, j),
1223                                                        paddr);
1224                                 kunmap_atomic(paddr, KM_USER0);
1225                         }
1226                 } else
1227                         j |= PAGE_COUNTER_MASK;
1228         }
1229         spin_unlock_irqrestore(&bitmap->lock, flags);
1230
1231         /* now sync the final page */
1232         if (lastpage != NULL) {
1233                 spin_lock_irqsave(&bitmap->lock, flags);
1234                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1235                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1236                         spin_unlock_irqrestore(&bitmap->lock, flags);
1237                         write_page(bitmap, lastpage, 0);
1238                 } else {
1239                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1240                         spin_unlock_irqrestore(&bitmap->lock, flags);
1241                 }
1242         }
1243
1244  done:
1245         if (bitmap->allclean == 0)
1246                 bitmap->mddev->thread->timeout =
1247                         bitmap->mddev->bitmap_info.daemon_sleep;
1248         mutex_unlock(&mddev->bitmap_info.mutex);
1249 }
1250
1251 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1252                                             sector_t offset, int *blocks,
1253                                             int create)
1254 __releases(bitmap->lock)
1255 __acquires(bitmap->lock)
1256 {
1257         /* If 'create', we might release the lock and reclaim it.
1258          * The lock must have been taken with interrupts enabled.
1259          * If !create, we don't release the lock.
1260          */
1261         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1262         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1263         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1264         sector_t csize;
1265
1266         if (bitmap_checkpage(bitmap, page, create) < 0) {
1267                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1268                 *blocks = csize - (offset & (csize- 1));
1269                 return NULL;
1270         }
1271         /* now locked ... */
1272
1273         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1274                 /* should we use the first or second counter field
1275                  * of the hijacked pointer? */
1276                 int hi = (pageoff > PAGE_COUNTER_MASK);
1277                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap) +
1278                                           PAGE_COUNTER_SHIFT - 1);
1279                 *blocks = csize - (offset & (csize- 1));
1280                 return  &((bitmap_counter_t *)
1281                           &bitmap->bp[page].map)[hi];
1282         } else { /* page is allocated */
1283                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1284                 *blocks = csize - (offset & (csize- 1));
1285                 return (bitmap_counter_t *)
1286                         &(bitmap->bp[page].map[pageoff]);
1287         }
1288 }
1289
1290 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1291 {
1292         if (!bitmap) return 0;
1293
1294         if (behind) {
1295                 int bw;
1296                 atomic_inc(&bitmap->behind_writes);
1297                 bw = atomic_read(&bitmap->behind_writes);
1298                 if (bw > bitmap->behind_writes_used)
1299                         bitmap->behind_writes_used = bw;
1300
1301                 PRINTK(KERN_DEBUG "inc write-behind count %d/%d\n",
1302                        bw, bitmap->max_write_behind);
1303         }
1304
1305         while (sectors) {
1306                 int blocks;
1307                 bitmap_counter_t *bmc;
1308
1309                 spin_lock_irq(&bitmap->lock);
1310                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 1);
1311                 if (!bmc) {
1312                         spin_unlock_irq(&bitmap->lock);
1313                         return 0;
1314                 }
1315
1316                 if (unlikely((*bmc & COUNTER_MAX) == COUNTER_MAX)) {
1317                         DEFINE_WAIT(__wait);
1318                         /* note that it is safe to do the prepare_to_wait
1319                          * after the test as long as we do it before dropping
1320                          * the spinlock.
1321                          */
1322                         prepare_to_wait(&bitmap->overflow_wait, &__wait,
1323                                         TASK_UNINTERRUPTIBLE);
1324                         spin_unlock_irq(&bitmap->lock);
1325                         blk_unplug(bitmap->mddev->queue);
1326                         schedule();
1327                         finish_wait(&bitmap->overflow_wait, &__wait);
1328                         continue;
1329                 }
1330
1331                 switch(*bmc) {
1332                 case 0:
1333                         bitmap_file_set_bit(bitmap, offset);
1334                         bitmap_count_page(bitmap,offset, 1);
1335                         blk_plug_device_unlocked(bitmap->mddev->queue);
1336                         /* fall through */
1337                 case 1:
1338                         *bmc = 2;
1339                 }
1340
1341                 (*bmc)++;
1342
1343                 spin_unlock_irq(&bitmap->lock);
1344
1345                 offset += blocks;
1346                 if (sectors > blocks)
1347                         sectors -= blocks;
1348                 else sectors = 0;
1349         }
1350         bitmap->allclean = 0;
1351         return 0;
1352 }
1353
1354 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1355                      int success, int behind)
1356 {
1357         if (!bitmap) return;
1358         if (behind) {
1359                 if (atomic_dec_and_test(&bitmap->behind_writes))
1360                         wake_up(&bitmap->behind_wait);
1361                 PRINTK(KERN_DEBUG "dec write-behind count %d/%d\n",
1362                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1363         }
1364         if (bitmap->mddev->degraded)
1365                 /* Never clear bits or update events_cleared when degraded */
1366                 success = 0;
1367
1368         while (sectors) {
1369                 int blocks;
1370                 unsigned long flags;
1371                 bitmap_counter_t *bmc;
1372
1373                 spin_lock_irqsave(&bitmap->lock, flags);
1374                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 0);
1375                 if (!bmc) {
1376                         spin_unlock_irqrestore(&bitmap->lock, flags);
1377                         return;
1378                 }
1379
1380                 if (success &&
1381                     bitmap->events_cleared < bitmap->mddev->events) {
1382                         bitmap->events_cleared = bitmap->mddev->events;
1383                         bitmap->need_sync = 1;
1384                         sysfs_notify_dirent(bitmap->sysfs_can_clear);
1385                 }
1386
1387                 if (!success && ! (*bmc & NEEDED_MASK))
1388                         *bmc |= NEEDED_MASK;
1389
1390                 if ((*bmc & COUNTER_MAX) == COUNTER_MAX)
1391                         wake_up(&bitmap->overflow_wait);
1392
1393                 (*bmc)--;
1394                 if (*bmc <= 2) {
1395                         set_page_attr(bitmap,
1396                                       filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1397                                       BITMAP_PAGE_CLEAN);
1398                 }
1399                 spin_unlock_irqrestore(&bitmap->lock, flags);
1400                 offset += blocks;
1401                 if (sectors > blocks)
1402                         sectors -= blocks;
1403                 else sectors = 0;
1404         }
1405 }
1406
1407 static int __bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
1408                                int degraded)
1409 {
1410         bitmap_counter_t *bmc;
1411         int rv;
1412         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1413                 *blocks = 1024;
1414                 return 1; /* always resync if no bitmap */
1415         }
1416         spin_lock_irq(&bitmap->lock);
1417         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1418         rv = 0;
1419         if (bmc) {
1420                 /* locked */
1421                 if (RESYNC(*bmc))
1422                         rv = 1;
1423                 else if (NEEDED(*bmc)) {
1424                         rv = 1;
1425                         if (!degraded) { /* don't set/clear bits if degraded */
1426                                 *bmc |= RESYNC_MASK;
1427                                 *bmc &= ~NEEDED_MASK;
1428                         }
1429                 }
1430         }
1431         spin_unlock_irq(&bitmap->lock);
1432         bitmap->allclean = 0;
1433         return rv;
1434 }
1435
1436 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
1437                       int degraded)
1438 {
1439         /* bitmap_start_sync must always report on multiples of whole
1440          * pages, otherwise resync (which is very PAGE_SIZE based) will
1441          * get confused.
1442          * So call __bitmap_start_sync repeatedly (if needed) until
1443          * At least PAGE_SIZE>>9 blocks are covered.
1444          * Return the 'or' of the result.
1445          */
1446         int rv = 0;
1447         int blocks1;
1448
1449         *blocks = 0;
1450         while (*blocks < (PAGE_SIZE>>9)) {
1451                 rv |= __bitmap_start_sync(bitmap, offset,
1452                                           &blocks1, degraded);
1453                 offset += blocks1;
1454                 *blocks += blocks1;
1455         }
1456         return rv;
1457 }
1458
1459 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int aborted)
1460 {
1461         bitmap_counter_t *bmc;
1462         unsigned long flags;
1463 /*
1464         if (offset == 0) printk("bitmap_end_sync 0 (%d)\n", aborted);
1465 */      if (bitmap == NULL) {
1466                 *blocks = 1024;
1467                 return;
1468         }
1469         spin_lock_irqsave(&bitmap->lock, flags);
1470         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1471         if (bmc == NULL)
1472                 goto unlock;
1473         /* locked */
1474 /*
1475         if (offset == 0) printk("bitmap_end sync found 0x%x, blocks %d\n", *bmc, *blocks);
1476 */
1477         if (RESYNC(*bmc)) {
1478                 *bmc &= ~RESYNC_MASK;
1479
1480                 if (!NEEDED(*bmc) && aborted)
1481                         *bmc |= NEEDED_MASK;
1482                 else {
1483                         if (*bmc <= 2) {
1484                                 set_page_attr(bitmap,
1485                                               filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1486                                               BITMAP_PAGE_CLEAN);
1487                         }
1488                 }
1489         }
1490  unlock:
1491         spin_unlock_irqrestore(&bitmap->lock, flags);
1492         bitmap->allclean = 0;
1493 }
1494
1495 void bitmap_close_sync(struct bitmap *bitmap)
1496 {
1497         /* Sync has finished, and any bitmap chunks that weren't synced
1498          * properly have been aborted.  It remains to us to clear the
1499          * RESYNC bit wherever it is still on
1500          */
1501         sector_t sector = 0;
1502         int blocks;
1503         if (!bitmap)
1504                 return;
1505         while (sector < bitmap->mddev->resync_max_sectors) {
1506                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1507                 sector += blocks;
1508         }
1509 }
1510
1511 void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector)
1512 {
1513         sector_t s = 0;
1514         int blocks;
1515
1516         if (!bitmap)
1517                 return;
1518         if (sector == 0) {
1519                 bitmap->last_end_sync = jiffies;
1520                 return;
1521         }
1522         if (time_before(jiffies, (bitmap->last_end_sync
1523                                   + bitmap->mddev->bitmap_info.daemon_sleep)))
1524                 return;
1525         wait_event(bitmap->mddev->recovery_wait,
1526                    atomic_read(&bitmap->mddev->recovery_active) == 0);
1527
1528         bitmap->mddev->curr_resync_completed = bitmap->mddev->curr_resync;
1529         if (bitmap->mddev->persistent)
1530                 set_bit(MD_CHANGE_CLEAN, &bitmap->mddev->flags);
1531         sector &= ~((1ULL << CHUNK_BLOCK_SHIFT(bitmap)) - 1);
1532         s = 0;
1533         while (s < sector && s < bitmap->mddev->resync_max_sectors) {
1534                 bitmap_end_sync(bitmap, s, &blocks, 0);
1535                 s += blocks;
1536         }
1537         bitmap->last_end_sync = jiffies;
1538         sysfs_notify(&bitmap->mddev->kobj, NULL, "sync_completed");
1539 }
1540
1541 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1542 {
1543         /* For each chunk covered by any of these sectors, set the
1544          * counter to 1 and set resync_needed.  They should all
1545          * be 0 at this point
1546          */
1547
1548         int secs;
1549         bitmap_counter_t *bmc;
1550         spin_lock_irq(&bitmap->lock);
1551         bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
1552         if (!bmc) {
1553                 spin_unlock_irq(&bitmap->lock);
1554                 return;
1555         }
1556         if (! *bmc) {
1557                 struct page *page;
1558                 *bmc = 1 | (needed?NEEDED_MASK:0);
1559                 bitmap_count_page(bitmap, offset, 1);
1560                 page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));
1561                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1562         }
1563         spin_unlock_irq(&bitmap->lock);
1564         bitmap->allclean = 0;
1565 }
1566
1567 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
1568 void bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1569 {
1570         unsigned long chunk;
1571
1572         for (chunk = s; chunk <= e; chunk++) {
1573                 sector_t sec = (sector_t)chunk << CHUNK_BLOCK_SHIFT(bitmap);
1574                 bitmap_set_memory_bits(bitmap, sec, 1);
1575                 bitmap_file_set_bit(bitmap, sec);
1576                 if (sec < bitmap->mddev->recovery_cp)
1577                         /* We are asserting that the array is dirty,
1578                          * so move the recovery_cp address back so
1579                          * that it is obvious that it is dirty
1580                          */
1581                         bitmap->mddev->recovery_cp = sec;
1582         }
1583 }
1584
1585 /*
1586  * flush out any pending updates
1587  */
1588 void bitmap_flush(mddev_t *mddev)
1589 {
1590         struct bitmap *bitmap = mddev->bitmap;
1591         long sleep;
1592
1593         if (!bitmap) /* there was no bitmap */
1594                 return;
1595
1596         /* run the daemon_work three time to ensure everything is flushed
1597          * that can be
1598          */
1599         sleep = mddev->bitmap_info.daemon_sleep * 2;
1600         bitmap->daemon_lastrun -= sleep;
1601         bitmap_daemon_work(mddev);
1602         bitmap->daemon_lastrun -= sleep;
1603         bitmap_daemon_work(mddev);
1604         bitmap->daemon_lastrun -= sleep;
1605         bitmap_daemon_work(mddev);
1606         bitmap_update_sb(bitmap);
1607 }
1608
1609 /*
1610  * free memory that was allocated
1611  */
1612 static void bitmap_free(struct bitmap *bitmap)
1613 {
1614         unsigned long k, pages;
1615         struct bitmap_page *bp;
1616
1617         if (!bitmap) /* there was no bitmap */
1618                 return;
1619
1620         /* release the bitmap file and kill the daemon */
1621         bitmap_file_put(bitmap);
1622
1623         bp = bitmap->bp;
1624         pages = bitmap->pages;
1625
1626         /* free all allocated memory */
1627
1628         if (bp) /* deallocate the page memory */
1629                 for (k = 0; k < pages; k++)
1630                         if (bp[k].map && !bp[k].hijacked)
1631                                 kfree(bp[k].map);
1632         kfree(bp);
1633         kfree(bitmap);
1634 }
1635
1636 void bitmap_destroy(mddev_t *mddev)
1637 {
1638         struct bitmap *bitmap = mddev->bitmap;
1639
1640         if (!bitmap) /* there was no bitmap */
1641                 return;
1642
1643         mutex_lock(&mddev->bitmap_info.mutex);
1644         mddev->bitmap = NULL; /* disconnect from the md device */
1645         mutex_unlock(&mddev->bitmap_info.mutex);
1646         if (mddev->thread)
1647                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1648
1649         if (bitmap->sysfs_can_clear)
1650                 sysfs_put(bitmap->sysfs_can_clear);
1651
1652         bitmap_free(bitmap);
1653 }
1654
1655 /*
1656  * initialize the bitmap structure
1657  * if this returns an error, bitmap_destroy must be called to do clean up
1658  */
1659 int bitmap_create(mddev_t *mddev)
1660 {
1661         struct bitmap *bitmap;
1662         sector_t blocks = mddev->resync_max_sectors;
1663         unsigned long chunks;
1664         unsigned long pages;
1665         struct file *file = mddev->bitmap_info.file;
1666         int err;
1667         sector_t start;
1668         struct sysfs_dirent *bm;
1669
1670         BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
1671
1672         if (!file && !mddev->bitmap_info.offset) /* bitmap disabled, nothing to do */
1673                 return 0;
1674
1675         BUG_ON(file && mddev->bitmap_info.offset);
1676
1677         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1678         if (!bitmap)
1679                 return -ENOMEM;
1680
1681         spin_lock_init(&bitmap->lock);
1682         atomic_set(&bitmap->pending_writes, 0);
1683         init_waitqueue_head(&bitmap->write_wait);
1684         init_waitqueue_head(&bitmap->overflow_wait);
1685         init_waitqueue_head(&bitmap->behind_wait);
1686
1687         bitmap->mddev = mddev;
1688
1689         bm = sysfs_get_dirent(mddev->kobj.sd, NULL, "bitmap");
1690         if (bm) {
1691                 bitmap->sysfs_can_clear = sysfs_get_dirent(bm, NULL, "can_clear");
1692                 sysfs_put(bm);
1693         } else
1694                 bitmap->sysfs_can_clear = NULL;
1695
1696         bitmap->file = file;
1697         if (file) {
1698                 get_file(file);
1699                 /* As future accesses to this file will use bmap,
1700                  * and bypass the page cache, we must sync the file
1701                  * first.
1702                  */
1703                 vfs_fsync(file, 1);
1704         }
1705         /* read superblock from bitmap file (this sets mddev->bitmap_info.chunksize) */
1706         if (!mddev->bitmap_info.external)
1707                 err = bitmap_read_sb(bitmap);
1708         else {
1709                 err = 0;
1710                 if (mddev->bitmap_info.chunksize == 0 ||
1711                     mddev->bitmap_info.daemon_sleep == 0)
1712                         /* chunksize and time_base need to be
1713                          * set first. */
1714                         err = -EINVAL;
1715         }
1716         if (err)
1717                 goto error;
1718
1719         bitmap->daemon_lastrun = jiffies;
1720         bitmap->chunkshift = ffz(~mddev->bitmap_info.chunksize);
1721
1722         /* now that chunksize and chunkshift are set, we can use these macros */
1723         chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) >>
1724                         CHUNK_BLOCK_SHIFT(bitmap);
1725         pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
1726
1727         BUG_ON(!pages);
1728
1729         bitmap->chunks = chunks;
1730         bitmap->pages = pages;
1731         bitmap->missing_pages = pages;
1732         bitmap->counter_bits = COUNTER_BITS;
1733
1734         bitmap->syncchunk = ~0UL;
1735
1736 #ifdef INJECT_FATAL_FAULT_1
1737         bitmap->bp = NULL;
1738 #else
1739         bitmap->bp = kzalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
1740 #endif
1741         err = -ENOMEM;
1742         if (!bitmap->bp)
1743                 goto error;
1744
1745         /* now that we have some pages available, initialize the in-memory
1746          * bitmap from the on-disk bitmap */
1747         start = 0;
1748         if (mddev->degraded == 0
1749             || bitmap->events_cleared == mddev->events)
1750                 /* no need to keep dirty bits to optimise a re-add of a missing device */
1751                 start = mddev->recovery_cp;
1752         err = bitmap_init_from_disk(bitmap, start);
1753
1754         if (err)
1755                 goto error;
1756
1757         printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
1758                 pages, bmname(bitmap));
1759
1760         mddev->bitmap = bitmap;
1761
1762         mddev->thread->timeout = mddev->bitmap_info.daemon_sleep;
1763         md_wakeup_thread(mddev->thread);
1764
1765         bitmap_update_sb(bitmap);
1766
1767         return (bitmap->flags & BITMAP_WRITE_ERROR) ? -EIO : 0;
1768
1769  error:
1770         bitmap_free(bitmap);
1771         return err;
1772 }
1773
1774 static ssize_t
1775 location_show(mddev_t *mddev, char *page)
1776 {
1777         ssize_t len;
1778         if (mddev->bitmap_info.file) {
1779                 len = sprintf(page, "file");
1780         } else if (mddev->bitmap_info.offset) {
1781                 len = sprintf(page, "%+lld", (long long)mddev->bitmap_info.offset);
1782         } else
1783                 len = sprintf(page, "none");
1784         len += sprintf(page+len, "\n");
1785         return len;
1786 }
1787
1788 static ssize_t
1789 location_store(mddev_t *mddev, const char *buf, size_t len)
1790 {
1791
1792         if (mddev->pers) {
1793                 if (!mddev->pers->quiesce)
1794                         return -EBUSY;
1795                 if (mddev->recovery || mddev->sync_thread)
1796                         return -EBUSY;
1797         }
1798
1799         if (mddev->bitmap || mddev->bitmap_info.file ||
1800             mddev->bitmap_info.offset) {
1801                 /* bitmap already configured.  Only option is to clear it */
1802                 if (strncmp(buf, "none", 4) != 0)
1803                         return -EBUSY;
1804                 if (mddev->pers) {
1805                         mddev->pers->quiesce(mddev, 1);
1806                         bitmap_destroy(mddev);
1807                         mddev->pers->quiesce(mddev, 0);
1808                 }
1809                 mddev->bitmap_info.offset = 0;
1810                 if (mddev->bitmap_info.file) {
1811                         struct file *f = mddev->bitmap_info.file;
1812                         mddev->bitmap_info.file = NULL;
1813                         restore_bitmap_write_access(f);
1814                         fput(f);
1815                 }
1816         } else {
1817                 /* No bitmap, OK to set a location */
1818                 long long offset;
1819                 if (strncmp(buf, "none", 4) == 0)
1820                         /* nothing to be done */;
1821                 else if (strncmp(buf, "file:", 5) == 0) {
1822                         /* Not supported yet */
1823                         return -EINVAL;
1824                 } else {
1825                         int rv;
1826                         if (buf[0] == '+')
1827                                 rv = strict_strtoll(buf+1, 10, &offset);
1828                         else
1829                                 rv = strict_strtoll(buf, 10, &offset);
1830                         if (rv)
1831                                 return rv;
1832                         if (offset == 0)
1833                                 return -EINVAL;
1834                         if (mddev->bitmap_info.external == 0 &&
1835                             mddev->major_version == 0 &&
1836                             offset != mddev->bitmap_info.default_offset)
1837                                 return -EINVAL;
1838                         mddev->bitmap_info.offset = offset;
1839                         if (mddev->pers) {
1840                                 mddev->pers->quiesce(mddev, 1);
1841                                 rv = bitmap_create(mddev);
1842                                 if (rv) {
1843                                         bitmap_destroy(mddev);
1844                                         mddev->bitmap_info.offset = 0;
1845                                 }
1846                                 mddev->pers->quiesce(mddev, 0);
1847                                 if (rv)
1848                                         return rv;
1849                         }
1850                 }
1851         }
1852         if (!mddev->external) {
1853                 /* Ensure new bitmap info is stored in
1854                  * metadata promptly.
1855                  */
1856                 set_bit(MD_CHANGE_DEVS, &mddev->flags);
1857                 md_wakeup_thread(mddev->thread);
1858         }
1859         return len;
1860 }
1861
1862 static struct md_sysfs_entry bitmap_location =
1863 __ATTR(location, S_IRUGO|S_IWUSR, location_show, location_store);
1864
1865 static ssize_t
1866 timeout_show(mddev_t *mddev, char *page)
1867 {
1868         ssize_t len;
1869         unsigned long secs = mddev->bitmap_info.daemon_sleep / HZ;
1870         unsigned long jifs = mddev->bitmap_info.daemon_sleep % HZ;
1871
1872         len = sprintf(page, "%lu", secs);
1873         if (jifs)
1874                 len += sprintf(page+len, ".%03u", jiffies_to_msecs(jifs));
1875         len += sprintf(page+len, "\n");
1876         return len;
1877 }
1878
1879 static ssize_t
1880 timeout_store(mddev_t *mddev, const char *buf, size_t len)
1881 {
1882         /* timeout can be set at any time */
1883         unsigned long timeout;
1884         int rv = strict_strtoul_scaled(buf, &timeout, 4);
1885         if (rv)
1886                 return rv;
1887
1888         /* just to make sure we don't overflow... */
1889         if (timeout >= LONG_MAX / HZ)
1890                 return -EINVAL;
1891
1892         timeout = timeout * HZ / 10000;
1893
1894         if (timeout >= MAX_SCHEDULE_TIMEOUT)
1895                 timeout = MAX_SCHEDULE_TIMEOUT-1;
1896         if (timeout < 1)
1897                 timeout = 1;
1898         mddev->bitmap_info.daemon_sleep = timeout;
1899         if (mddev->thread) {
1900                 /* if thread->timeout is MAX_SCHEDULE_TIMEOUT, then
1901                  * the bitmap is all clean and we don't need to
1902                  * adjust the timeout right now
1903                  */
1904                 if (mddev->thread->timeout < MAX_SCHEDULE_TIMEOUT) {
1905                         mddev->thread->timeout = timeout;
1906                         md_wakeup_thread(mddev->thread);
1907                 }
1908         }
1909         return len;
1910 }
1911
1912 static struct md_sysfs_entry bitmap_timeout =
1913 __ATTR(time_base, S_IRUGO|S_IWUSR, timeout_show, timeout_store);
1914
1915 static ssize_t
1916 backlog_show(mddev_t *mddev, char *page)
1917 {
1918         return sprintf(page, "%lu\n", mddev->bitmap_info.max_write_behind);
1919 }
1920
1921 static ssize_t
1922 backlog_store(mddev_t *mddev, const char *buf, size_t len)
1923 {
1924         unsigned long backlog;
1925         int rv = strict_strtoul(buf, 10, &backlog);
1926         if (rv)
1927                 return rv;
1928         if (backlog > COUNTER_MAX)
1929                 return -EINVAL;
1930         mddev->bitmap_info.max_write_behind = backlog;
1931         return len;
1932 }
1933
1934 static struct md_sysfs_entry bitmap_backlog =
1935 __ATTR(backlog, S_IRUGO|S_IWUSR, backlog_show, backlog_store);
1936
1937 static ssize_t
1938 chunksize_show(mddev_t *mddev, char *page)
1939 {
1940         return sprintf(page, "%lu\n", mddev->bitmap_info.chunksize);
1941 }
1942
1943 static ssize_t
1944 chunksize_store(mddev_t *mddev, const char *buf, size_t len)
1945 {
1946         /* Can only be changed when no bitmap is active */
1947         int rv;
1948         unsigned long csize;
1949         if (mddev->bitmap)
1950                 return -EBUSY;
1951         rv = strict_strtoul(buf, 10, &csize);
1952         if (rv)
1953                 return rv;
1954         if (csize < 512 ||
1955             !is_power_of_2(csize))
1956                 return -EINVAL;
1957         mddev->bitmap_info.chunksize = csize;
1958         return len;
1959 }
1960
1961 static struct md_sysfs_entry bitmap_chunksize =
1962 __ATTR(chunksize, S_IRUGO|S_IWUSR, chunksize_show, chunksize_store);
1963
1964 static ssize_t metadata_show(mddev_t *mddev, char *page)
1965 {
1966         return sprintf(page, "%s\n", (mddev->bitmap_info.external
1967                                       ? "external" : "internal"));
1968 }
1969
1970 static ssize_t metadata_store(mddev_t *mddev, const char *buf, size_t len)
1971 {
1972         if (mddev->bitmap ||
1973             mddev->bitmap_info.file ||
1974             mddev->bitmap_info.offset)
1975                 return -EBUSY;
1976         if (strncmp(buf, "external", 8) == 0)
1977                 mddev->bitmap_info.external = 1;
1978         else if (strncmp(buf, "internal", 8) == 0)
1979                 mddev->bitmap_info.external = 0;
1980         else
1981                 return -EINVAL;
1982         return len;
1983 }
1984
1985 static struct md_sysfs_entry bitmap_metadata =
1986 __ATTR(metadata, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
1987
1988 static ssize_t can_clear_show(mddev_t *mddev, char *page)
1989 {
1990         int len;
1991         if (mddev->bitmap)
1992                 len = sprintf(page, "%s\n", (mddev->bitmap->need_sync ?
1993                                              "false" : "true"));
1994         else
1995                 len = sprintf(page, "\n");
1996         return len;
1997 }
1998
1999 static ssize_t can_clear_store(mddev_t *mddev, const char *buf, size_t len)
2000 {
2001         if (mddev->bitmap == NULL)
2002                 return -ENOENT;
2003         if (strncmp(buf, "false", 5) == 0)
2004                 mddev->bitmap->need_sync = 1;
2005         else if (strncmp(buf, "true", 4) == 0) {
2006                 if (mddev->degraded)
2007                         return -EBUSY;
2008                 mddev->bitmap->need_sync = 0;
2009         } else
2010                 return -EINVAL;
2011         return len;
2012 }
2013
2014 static struct md_sysfs_entry bitmap_can_clear =
2015 __ATTR(can_clear, S_IRUGO|S_IWUSR, can_clear_show, can_clear_store);
2016
2017 static ssize_t
2018 behind_writes_used_show(mddev_t *mddev, char *page)
2019 {
2020         if (mddev->bitmap == NULL)
2021                 return sprintf(page, "0\n");
2022         return sprintf(page, "%lu\n",
2023                        mddev->bitmap->behind_writes_used);
2024 }
2025
2026 static ssize_t
2027 behind_writes_used_reset(mddev_t *mddev, const char *buf, size_t len)
2028 {
2029         if (mddev->bitmap)
2030                 mddev->bitmap->behind_writes_used = 0;
2031         return len;
2032 }
2033
2034 static struct md_sysfs_entry max_backlog_used =
2035 __ATTR(max_backlog_used, S_IRUGO | S_IWUSR,
2036        behind_writes_used_show, behind_writes_used_reset);
2037
2038 static struct attribute *md_bitmap_attrs[] = {
2039         &bitmap_location.attr,
2040         &bitmap_timeout.attr,
2041         &bitmap_backlog.attr,
2042         &bitmap_chunksize.attr,
2043         &bitmap_metadata.attr,
2044         &bitmap_can_clear.attr,
2045         &max_backlog_used.attr,
2046         NULL
2047 };
2048 struct attribute_group md_bitmap_group = {
2049         .name = "bitmap",
2050         .attrs = md_bitmap_attrs,
2051 };
2052
2053
2054 /* the bitmap API -- for raid personalities */
2055 EXPORT_SYMBOL(bitmap_startwrite);
2056 EXPORT_SYMBOL(bitmap_endwrite);
2057 EXPORT_SYMBOL(bitmap_start_sync);
2058 EXPORT_SYMBOL(bitmap_end_sync);
2059 EXPORT_SYMBOL(bitmap_unplug);
2060 EXPORT_SYMBOL(bitmap_close_sync);
2061 EXPORT_SYMBOL(bitmap_cond_end_sync);