linux/drivers/md/bitmap.c
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   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
  33static 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 */
  48static 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        mappage = kzalloc(PAGE_SIZE, GFP_NOIO);
  76        spin_lock_irq(&bitmap->lock);
  77
  78        if (mappage == NULL) {
  79                pr_debug("md/bitmap: map page allocation failed, hijacking\n");
  80                /* failed - set the hijacked flag so that we can use the
  81                 * pointer as a counter */
  82                if (!bitmap->bp[page].map)
  83                        bitmap->bp[page].hijacked = 1;
  84        } else if (bitmap->bp[page].map ||
  85                   bitmap->bp[page].hijacked) {
  86                /* somebody beat us to getting the page */
  87                kfree(mappage);
  88                return 0;
  89        } else {
  90
  91                /* no page was in place and we have one, so install it */
  92
  93                bitmap->bp[page].map = mappage;
  94                bitmap->missing_pages--;
  95        }
  96        return 0;
  97}
  98
  99/* if page is completely empty, put it back on the free list, or dealloc it */
 100/* if page was hijacked, unmark the flag so it might get alloced next time */
 101/* Note: lock should be held when calling this */
 102static void bitmap_checkfree(struct bitmap_counts *bitmap, unsigned long page)
 103{
 104        char *ptr;
 105
 106        if (bitmap->bp[page].count) /* page is still busy */
 107                return;
 108
 109        /* page is no longer in use, it can be released */
 110
 111        if (bitmap->bp[page].hijacked) { /* page was hijacked, undo this now */
 112                bitmap->bp[page].hijacked = 0;
 113                bitmap->bp[page].map = NULL;
 114        } else {
 115                /* normal case, free the page */
 116                ptr = bitmap->bp[page].map;
 117                bitmap->bp[page].map = NULL;
 118                bitmap->missing_pages++;
 119                kfree(ptr);
 120        }
 121}
 122
 123/*
 124 * bitmap file handling - read and write the bitmap file and its superblock
 125 */
 126
 127/*
 128 * basic page I/O operations
 129 */
 130
 131/* IO operations when bitmap is stored near all superblocks */
 132static int read_sb_page(struct mddev *mddev, loff_t offset,
 133                        struct page *page,
 134                        unsigned long index, int size)
 135{
 136        /* choose a good rdev and read the page from there */
 137
 138        struct md_rdev *rdev;
 139        sector_t target;
 140
 141        rdev_for_each(rdev, mddev) {
 142                if (! test_bit(In_sync, &rdev->flags)
 143                    || test_bit(Faulty, &rdev->flags))
 144                        continue;
 145
 146                target = offset + index * (PAGE_SIZE/512);
 147
 148                if (sync_page_io(rdev, target,
 149                                 roundup(size, bdev_logical_block_size(rdev->bdev)),
 150                                 page, READ, true)) {
 151                        page->index = index;
 152                        return 0;
 153                }
 154        }
 155        return -EIO;
 156}
 157
 158static struct md_rdev *next_active_rdev(struct md_rdev *rdev, struct mddev *mddev)
 159{
 160        /* Iterate the disks of an mddev, using rcu to protect access to the
 161         * linked list, and raising the refcount of devices we return to ensure
 162         * they don't disappear while in use.
 163         * As devices are only added or removed when raid_disk is < 0 and
 164         * nr_pending is 0 and In_sync is clear, the entries we return will
 165         * still be in the same position on the list when we re-enter
 166         * list_for_each_entry_continue_rcu.
 167         */
 168        rcu_read_lock();
 169        if (rdev == NULL)
 170                /* start at the beginning */
 171                rdev = list_entry_rcu(&mddev->disks, struct md_rdev, same_set);
 172        else {
 173                /* release the previous rdev and start from there. */
 174                rdev_dec_pending(rdev, mddev);
 175        }
 176        list_for_each_entry_continue_rcu(rdev, &mddev->disks, same_set) {
 177                if (rdev->raid_disk >= 0 &&
 178                    !test_bit(Faulty, &rdev->flags)) {
 179                        /* this is a usable devices */
 180                        atomic_inc(&rdev->nr_pending);
 181                        rcu_read_unlock();
 182                        return rdev;
 183                }
 184        }
 185        rcu_read_unlock();
 186        return NULL;
 187}
 188
 189static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
 190{
 191        struct md_rdev *rdev = NULL;
 192        struct block_device *bdev;
 193        struct mddev *mddev = bitmap->mddev;
 194        struct bitmap_storage *store = &bitmap->storage;
 195
 196        while ((rdev = next_active_rdev(rdev, mddev)) != NULL) {
 197                int size = PAGE_SIZE;
 198                loff_t offset = mddev->bitmap_info.offset;
 199
 200                bdev = (rdev->meta_bdev) ? rdev->meta_bdev : rdev->bdev;
 201
 202                if (page->index == store->file_pages-1) {
 203                        int last_page_size = store->bytes & (PAGE_SIZE-1);
 204                        if (last_page_size == 0)
 205                                last_page_size = PAGE_SIZE;
 206                        size = roundup(last_page_size,
 207                                       bdev_logical_block_size(bdev));
 208                }
 209                /* Just make sure we aren't corrupting data or
 210                 * metadata
 211                 */
 212                if (mddev->external) {
 213                        /* Bitmap could be anywhere. */
 214                        if (rdev->sb_start + offset + (page->index
 215                                                       * (PAGE_SIZE/512))
 216                            > rdev->data_offset
 217                            &&
 218                            rdev->sb_start + offset
 219                            < (rdev->data_offset + mddev->dev_sectors
 220                             + (PAGE_SIZE/512)))
 221                                goto bad_alignment;
 222                } else if (offset < 0) {
 223                        /* DATA  BITMAP METADATA  */
 224                        if (offset
 225                            + (long)(page->index * (PAGE_SIZE/512))
 226                            + size/512 > 0)
 227                                /* bitmap runs in to metadata */
 228                                goto bad_alignment;
 229                        if (rdev->data_offset + mddev->dev_sectors
 230                            > rdev->sb_start + offset)
 231                                /* data runs in to bitmap */
 232                                goto bad_alignment;
 233                } else if (rdev->sb_start < rdev->data_offset) {
 234                        /* METADATA BITMAP DATA */
 235                        if (rdev->sb_start
 236                            + offset
 237                            + page->index*(PAGE_SIZE/512) + size/512
 238                            > rdev->data_offset)
 239                                /* bitmap runs in to data */
 240                                goto bad_alignment;
 241                } else {
 242                        /* DATA METADATA BITMAP - no problems */
 243                }
 244                md_super_write(mddev, rdev,
 245                               rdev->sb_start + offset
 246                               + page->index * (PAGE_SIZE/512),
 247                               size,
 248                               page);
 249        }
 250
 251        if (wait)
 252                md_super_wait(mddev);
 253        return 0;
 254
 255 bad_alignment:
 256        return -EINVAL;
 257}
 258
 259static void bitmap_file_kick(struct bitmap *bitmap);
 260/*
 261 * write out a page to a file
 262 */
 263static void write_page(struct bitmap *bitmap, struct page *page, int wait)
 264{
 265        struct buffer_head *bh;
 266
 267        if (bitmap->storage.file == NULL) {
 268                switch (write_sb_page(bitmap, page, wait)) {
 269                case -EINVAL:
 270                        set_bit(BITMAP_WRITE_ERROR, &bitmap->flags);
 271                }
 272        } else {
 273
 274                bh = page_buffers(page);
 275
 276                while (bh && bh->b_blocknr) {
 277                        atomic_inc(&bitmap->pending_writes);
 278                        set_buffer_locked(bh);
 279                        set_buffer_mapped(bh);
 280                        submit_bh(WRITE | REQ_SYNC, bh);
 281                        bh = bh->b_this_page;
 282                }
 283
 284                if (wait)
 285                        wait_event(bitmap->write_wait,
 286                                   atomic_read(&bitmap->pending_writes)==0);
 287        }
 288        if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
 289                bitmap_file_kick(bitmap);
 290}
 291
 292static void end_bitmap_write(struct buffer_head *bh, int uptodate)
 293{
 294        struct bitmap *bitmap = bh->b_private;
 295
 296        if (!uptodate)
 297                set_bit(BITMAP_WRITE_ERROR, &bitmap->flags);
 298        if (atomic_dec_and_test(&bitmap->pending_writes))
 299                wake_up(&bitmap->write_wait);
 300}
 301
 302/* copied from buffer.c */
 303static void
 304__clear_page_buffers(struct page *page)
 305{
 306        ClearPagePrivate(page);
 307        set_page_private(page, 0);
 308        page_cache_release(page);
 309}
 310static void free_buffers(struct page *page)
 311{
 312        struct buffer_head *bh;
 313
 314        if (!PagePrivate(page))
 315                return;
 316
 317        bh = page_buffers(page);
 318        while (bh) {
 319                struct buffer_head *next = bh->b_this_page;
 320                free_buffer_head(bh);
 321                bh = next;
 322        }
 323        __clear_page_buffers(page);
 324        put_page(page);
 325}
 326
 327/* read a page from a file.
 328 * We both read the page, and attach buffers to the page to record the
 329 * address of each block (using bmap).  These addresses will be used
 330 * to write the block later, completely bypassing the filesystem.
 331 * This usage is similar to how swap files are handled, and allows us
 332 * to write to a file with no concerns of memory allocation failing.
 333 */
 334static int read_page(struct file *file, unsigned long index,
 335                     struct bitmap *bitmap,
 336                     unsigned long count,
 337                     struct page *page)
 338{
 339        int ret = 0;
 340        struct inode *inode = file->f_path.dentry->d_inode;
 341        struct buffer_head *bh;
 342        sector_t block;
 343
 344        pr_debug("read bitmap file (%dB @ %llu)\n", (int)PAGE_SIZE,
 345                 (unsigned long long)index << PAGE_SHIFT);
 346
 347        bh = alloc_page_buffers(page, 1<<inode->i_blkbits, 0);
 348        if (!bh) {
 349                ret = -ENOMEM;
 350                goto out;
 351        }
 352        attach_page_buffers(page, bh);
 353        block = index << (PAGE_SHIFT - inode->i_blkbits);
 354        while (bh) {
 355                if (count == 0)
 356                        bh->b_blocknr = 0;
 357                else {
 358                        bh->b_blocknr = bmap(inode, block);
 359                        if (bh->b_blocknr == 0) {
 360                                /* Cannot use this file! */
 361                                ret = -EINVAL;
 362                                goto out;
 363                        }
 364                        bh->b_bdev = inode->i_sb->s_bdev;
 365                        if (count < (1<<inode->i_blkbits))
 366                                count = 0;
 367                        else
 368                                count -= (1<<inode->i_blkbits);
 369
 370                        bh->b_end_io = end_bitmap_write;
 371                        bh->b_private = bitmap;
 372                        atomic_inc(&bitmap->pending_writes);
 373                        set_buffer_locked(bh);
 374                        set_buffer_mapped(bh);
 375                        submit_bh(READ, bh);
 376                }
 377                block++;
 378                bh = bh->b_this_page;
 379        }
 380        page->index = index;
 381
 382        wait_event(bitmap->write_wait,
 383                   atomic_read(&bitmap->pending_writes)==0);
 384        if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
 385                ret = -EIO;
 386out:
 387        if (ret)
 388                printk(KERN_ALERT "md: bitmap read error: (%dB @ %llu): %d\n",
 389                        (int)PAGE_SIZE,
 390                        (unsigned long long)index << PAGE_SHIFT,
 391                        ret);
 392        return ret;
 393}
 394
 395/*
 396 * bitmap file superblock operations
 397 */
 398
 399/* update the event counter and sync the superblock to disk */
 400void bitmap_update_sb(struct bitmap *bitmap)
 401{
 402        bitmap_super_t *sb;
 403
 404        if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
 405                return;
 406        if (bitmap->mddev->bitmap_info.external)
 407                return;
 408        if (!bitmap->storage.sb_page) /* no superblock */
 409                return;
 410        sb = kmap_atomic(bitmap->storage.sb_page);
 411        sb->events = cpu_to_le64(bitmap->mddev->events);
 412        if (bitmap->mddev->events < bitmap->events_cleared)
 413                /* rocking back to read-only */
 414                bitmap->events_cleared = bitmap->mddev->events;
 415        sb->events_cleared = cpu_to_le64(bitmap->events_cleared);
 416        sb->state = cpu_to_le32(bitmap->flags);
 417        /* Just in case these have been changed via sysfs: */
 418        sb->daemon_sleep = cpu_to_le32(bitmap->mddev->bitmap_info.daemon_sleep/HZ);
 419        sb->write_behind = cpu_to_le32(bitmap->mddev->bitmap_info.max_write_behind);
 420        /* This might have been changed by a reshape */
 421        sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 422        sb->chunksize = cpu_to_le32(bitmap->mddev->bitmap_info.chunksize);
 423        sb->sectors_reserved = cpu_to_le32(bitmap->mddev->
 424                                           bitmap_info.space);
 425        kunmap_atomic(sb);
 426        write_page(bitmap, bitmap->storage.sb_page, 1);
 427}
 428
 429/* print out the bitmap file superblock */
 430void bitmap_print_sb(struct bitmap *bitmap)
 431{
 432        bitmap_super_t *sb;
 433
 434        if (!bitmap || !bitmap->storage.sb_page)
 435                return;
 436        sb = kmap_atomic(bitmap->storage.sb_page);
 437        printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
 438        printk(KERN_DEBUG "         magic: %08x\n", le32_to_cpu(sb->magic));
 439        printk(KERN_DEBUG "       version: %d\n", le32_to_cpu(sb->version));
 440        printk(KERN_DEBUG "          uuid: %08x.%08x.%08x.%08x\n",
 441                                        *(__u32 *)(sb->uuid+0),
 442                                        *(__u32 *)(sb->uuid+4),
 443                                        *(__u32 *)(sb->uuid+8),
 444                                        *(__u32 *)(sb->uuid+12));
 445        printk(KERN_DEBUG "        events: %llu\n",
 446                        (unsigned long long) le64_to_cpu(sb->events));
 447        printk(KERN_DEBUG "events cleared: %llu\n",
 448                        (unsigned long long) le64_to_cpu(sb->events_cleared));
 449        printk(KERN_DEBUG "         state: %08x\n", le32_to_cpu(sb->state));
 450        printk(KERN_DEBUG "     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
 451        printk(KERN_DEBUG "  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
 452        printk(KERN_DEBUG "     sync size: %llu KB\n",
 453                        (unsigned long long)le64_to_cpu(sb->sync_size)/2);
 454        printk(KERN_DEBUG "max write behind: %d\n", le32_to_cpu(sb->write_behind));
 455        kunmap_atomic(sb);
 456}
 457
 458/*
 459 * bitmap_new_disk_sb
 460 * @bitmap
 461 *
 462 * This function is somewhat the reverse of bitmap_read_sb.  bitmap_read_sb
 463 * reads and verifies the on-disk bitmap superblock and populates bitmap_info.
 464 * This function verifies 'bitmap_info' and populates the on-disk bitmap
 465 * structure, which is to be written to disk.
 466 *
 467 * Returns: 0 on success, -Exxx on error
 468 */
 469static int bitmap_new_disk_sb(struct bitmap *bitmap)
 470{
 471        bitmap_super_t *sb;
 472        unsigned long chunksize, daemon_sleep, write_behind;
 473
 474        bitmap->storage.sb_page = alloc_page(GFP_KERNEL);
 475        if (bitmap->storage.sb_page == NULL)
 476                return -ENOMEM;
 477        bitmap->storage.sb_page->index = 0;
 478
 479        sb = kmap_atomic(bitmap->storage.sb_page);
 480
 481        sb->magic = cpu_to_le32(BITMAP_MAGIC);
 482        sb->version = cpu_to_le32(BITMAP_MAJOR_HI);
 483
 484        chunksize = bitmap->mddev->bitmap_info.chunksize;
 485        BUG_ON(!chunksize);
 486        if (!is_power_of_2(chunksize)) {
 487                kunmap_atomic(sb);
 488                printk(KERN_ERR "bitmap chunksize not a power of 2\n");
 489                return -EINVAL;
 490        }
 491        sb->chunksize = cpu_to_le32(chunksize);
 492
 493        daemon_sleep = bitmap->mddev->bitmap_info.daemon_sleep;
 494        if (!daemon_sleep ||
 495            (daemon_sleep < 1) || (daemon_sleep > MAX_SCHEDULE_TIMEOUT)) {
 496                printk(KERN_INFO "Choosing daemon_sleep default (5 sec)\n");
 497                daemon_sleep = 5 * HZ;
 498        }
 499        sb->daemon_sleep = cpu_to_le32(daemon_sleep);
 500        bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 501
 502        /*
 503         * FIXME: write_behind for RAID1.  If not specified, what
 504         * is a good choice?  We choose COUNTER_MAX / 2 arbitrarily.
 505         */
 506        write_behind = bitmap->mddev->bitmap_info.max_write_behind;
 507        if (write_behind > COUNTER_MAX)
 508                write_behind = COUNTER_MAX / 2;
 509        sb->write_behind = cpu_to_le32(write_behind);
 510        bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 511
 512        /* keep the array size field of the bitmap superblock up to date */
 513        sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 514
 515        memcpy(sb->uuid, bitmap->mddev->uuid, 16);
 516
 517        set_bit(BITMAP_STALE, &bitmap->flags);
 518        sb->state = cpu_to_le32(bitmap->flags);
 519        bitmap->events_cleared = bitmap->mddev->events;
 520        sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
 521
 522        kunmap_atomic(sb);
 523
 524        return 0;
 525}
 526
 527/* read the superblock from the bitmap file and initialize some bitmap fields */
 528static int bitmap_read_sb(struct bitmap *bitmap)
 529{
 530        char *reason = NULL;
 531        bitmap_super_t *sb;
 532        unsigned long chunksize, daemon_sleep, write_behind;
 533        unsigned long long events;
 534        unsigned long sectors_reserved = 0;
 535        int err = -EINVAL;
 536        struct page *sb_page;
 537
 538        if (!bitmap->storage.file && !bitmap->mddev->bitmap_info.offset) {
 539                chunksize = 128 * 1024 * 1024;
 540                daemon_sleep = 5 * HZ;
 541                write_behind = 0;
 542                set_bit(BITMAP_STALE, &bitmap->flags);
 543                err = 0;
 544                goto out_no_sb;
 545        }
 546        /* page 0 is the superblock, read it... */
 547        sb_page = alloc_page(GFP_KERNEL);
 548        if (!sb_page)
 549                return -ENOMEM;
 550        bitmap->storage.sb_page = sb_page;
 551
 552        if (bitmap->storage.file) {
 553                loff_t isize = i_size_read(bitmap->storage.file->f_mapping->host);
 554                int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
 555
 556                err = read_page(bitmap->storage.file, 0,
 557                                bitmap, bytes, sb_page);
 558        } else {
 559                err = read_sb_page(bitmap->mddev,
 560                                   bitmap->mddev->bitmap_info.offset,
 561                                   sb_page,
 562                                   0, sizeof(bitmap_super_t));
 563        }
 564        if (err)
 565                return err;
 566
 567        sb = kmap_atomic(sb_page);
 568
 569        chunksize = le32_to_cpu(sb->chunksize);
 570        daemon_sleep = le32_to_cpu(sb->daemon_sleep) * HZ;
 571        write_behind = le32_to_cpu(sb->write_behind);
 572        sectors_reserved = le32_to_cpu(sb->sectors_reserved);
 573
 574        /* verify that the bitmap-specific fields are valid */
 575        if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
 576                reason = "bad magic";
 577        else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
 578                 le32_to_cpu(sb->version) > BITMAP_MAJOR_HI)
 579                reason = "unrecognized superblock version";
 580        else if (chunksize < 512)
 581                reason = "bitmap chunksize too small";
 582        else if (!is_power_of_2(chunksize))
 583                reason = "bitmap chunksize not a power of 2";
 584        else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT)
 585                reason = "daemon sleep period out of range";
 586        else if (write_behind > COUNTER_MAX)
 587                reason = "write-behind limit out of range (0 - 16383)";
 588        if (reason) {
 589                printk(KERN_INFO "%s: invalid bitmap file superblock: %s\n",
 590                        bmname(bitmap), reason);
 591                goto out;
 592        }
 593
 594        /* keep the array size field of the bitmap superblock up to date */
 595        sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 596
 597        if (bitmap->mddev->persistent) {
 598                /*
 599                 * We have a persistent array superblock, so compare the
 600                 * bitmap's UUID and event counter to the mddev's
 601                 */
 602                if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
 603                        printk(KERN_INFO
 604                               "%s: bitmap superblock UUID mismatch\n",
 605                               bmname(bitmap));
 606                        goto out;
 607                }
 608                events = le64_to_cpu(sb->events);
 609                if (events < bitmap->mddev->events) {
 610                        printk(KERN_INFO
 611                               "%s: bitmap file is out of date (%llu < %llu) "
 612                               "-- forcing full recovery\n",
 613                               bmname(bitmap), events,
 614                               (unsigned long long) bitmap->mddev->events);
 615                        set_bit(BITMAP_STALE, &bitmap->flags);
 616                }
 617        }
 618
 619        /* assign fields using values from superblock */
 620        bitmap->flags |= le32_to_cpu(sb->state);
 621        if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
 622                set_bit(BITMAP_HOSTENDIAN, &bitmap->flags);
 623        bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
 624        err = 0;
 625out:
 626        kunmap_atomic(sb);
 627out_no_sb:
 628        if (test_bit(BITMAP_STALE, &bitmap->flags))
 629                bitmap->events_cleared = bitmap->mddev->events;
 630        bitmap->mddev->bitmap_info.chunksize = chunksize;
 631        bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 632        bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 633        if (bitmap->mddev->bitmap_info.space == 0 ||
 634            bitmap->mddev->bitmap_info.space > sectors_reserved)
 635                bitmap->mddev->bitmap_info.space = sectors_reserved;
 636        if (err)
 637                bitmap_print_sb(bitmap);
 638        return err;
 639}
 640
 641/*
 642 * general bitmap file operations
 643 */
 644
 645/*
 646 * on-disk bitmap:
 647 *
 648 * Use one bit per "chunk" (block set). We do the disk I/O on the bitmap
 649 * file a page at a time. There's a superblock at the start of the file.
 650 */
 651/* calculate the index of the page that contains this bit */
 652static inline unsigned long file_page_index(struct bitmap_storage *store,
 653                                            unsigned long chunk)
 654{
 655        if (store->sb_page)
 656                chunk += sizeof(bitmap_super_t) << 3;
 657        return chunk >> PAGE_BIT_SHIFT;
 658}
 659
 660/* calculate the (bit) offset of this bit within a page */
 661static inline unsigned long file_page_offset(struct bitmap_storage *store,
 662                                             unsigned long chunk)
 663{
 664        if (store->sb_page)
 665                chunk += sizeof(bitmap_super_t) << 3;
 666        return chunk & (PAGE_BITS - 1);
 667}
 668
 669/*
 670 * return a pointer to the page in the filemap that contains the given bit
 671 *
 672 * this lookup is complicated by the fact that the bitmap sb might be exactly
 673 * 1 page (e.g., x86) or less than 1 page -- so the bitmap might start on page
 674 * 0 or page 1
 675 */
 676static inline struct page *filemap_get_page(struct bitmap_storage *store,
 677                                            unsigned long chunk)
 678{
 679        if (file_page_index(store, chunk) >= store->file_pages)
 680                return NULL;
 681        return store->filemap[file_page_index(store, chunk)
 682                              - file_page_index(store, 0)];
 683}
 684
 685static int bitmap_storage_alloc(struct bitmap_storage *store,
 686                                unsigned long chunks, int with_super)
 687{
 688        int pnum;
 689        unsigned long num_pages;
 690        unsigned long bytes;
 691
 692        bytes = DIV_ROUND_UP(chunks, 8);
 693        if (with_super)
 694                bytes += sizeof(bitmap_super_t);
 695
 696        num_pages = DIV_ROUND_UP(bytes, PAGE_SIZE);
 697
 698        store->filemap = kmalloc(sizeof(struct page *)
 699                                 * num_pages, GFP_KERNEL);
 700        if (!store->filemap)
 701                return -ENOMEM;
 702
 703        if (with_super && !store->sb_page) {
 704                store->sb_page = alloc_page(GFP_KERNEL|__GFP_ZERO);
 705                if (store->sb_page == NULL)
 706                        return -ENOMEM;
 707                store->sb_page->index = 0;
 708        }
 709        pnum = 0;
 710        if (store->sb_page) {
 711                store->filemap[0] = store->sb_page;
 712                pnum = 1;
 713        }
 714        for ( ; pnum < num_pages; pnum++) {
 715                store->filemap[pnum] = alloc_page(GFP_KERNEL|__GFP_ZERO);
 716                if (!store->filemap[pnum]) {
 717                        store->file_pages = pnum;
 718                        return -ENOMEM;
 719                }
 720                store->filemap[pnum]->index = pnum;
 721        }
 722        store->file_pages = pnum;
 723
 724        /* We need 4 bits per page, rounded up to a multiple
 725         * of sizeof(unsigned long) */
 726        store->filemap_attr = kzalloc(
 727                roundup(DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
 728                GFP_KERNEL);
 729        if (!store->filemap_attr)
 730                return -ENOMEM;
 731
 732        store->bytes = bytes;
 733
 734        return 0;
 735}
 736
 737static void bitmap_file_unmap(struct bitmap_storage *store)
 738{
 739        struct page **map, *sb_page;
 740        int pages;
 741        struct file *file;
 742
 743        file = store->file;
 744        map = store->filemap;
 745        pages = store->file_pages;
 746        sb_page = store->sb_page;
 747
 748        while (pages--)
 749                if (map[pages] != sb_page) /* 0 is sb_page, release it below */
 750                        free_buffers(map[pages]);
 751        kfree(map);
 752        kfree(store->filemap_attr);
 753
 754        if (sb_page)
 755                free_buffers(sb_page);
 756
 757        if (file) {
 758                struct inode *inode = file->f_path.dentry->d_inode;
 759                invalidate_mapping_pages(inode->i_mapping, 0, -1);
 760                fput(file);
 761        }
 762}
 763
 764/*
 765 * bitmap_file_kick - if an error occurs while manipulating the bitmap file
 766 * then it is no longer reliable, so we stop using it and we mark the file
 767 * as failed in the superblock
 768 */
 769static void bitmap_file_kick(struct bitmap *bitmap)
 770{
 771        char *path, *ptr = NULL;
 772
 773        if (!test_and_set_bit(BITMAP_STALE, &bitmap->flags)) {
 774                bitmap_update_sb(bitmap);
 775
 776                if (bitmap->storage.file) {
 777                        path = kmalloc(PAGE_SIZE, GFP_KERNEL);
 778                        if (path)
 779                                ptr = d_path(&bitmap->storage.file->f_path,
 780                                             path, PAGE_SIZE);
 781
 782                        printk(KERN_ALERT
 783                              "%s: kicking failed bitmap file %s from array!\n",
 784                              bmname(bitmap), IS_ERR(ptr) ? "" : ptr);
 785
 786                        kfree(path);
 787                } else
 788                        printk(KERN_ALERT
 789                               "%s: disabling internal bitmap due to errors\n",
 790                               bmname(bitmap));
 791        }
 792}
 793
 794enum bitmap_page_attr {
 795        BITMAP_PAGE_DIRTY = 0,     /* there are set bits that need to be synced */
 796        BITMAP_PAGE_PENDING = 1,   /* there are bits that are being cleaned.
 797                                    * i.e. counter is 1 or 2. */
 798        BITMAP_PAGE_NEEDWRITE = 2, /* there are cleared bits that need to be synced */
 799};
 800
 801static inline void set_page_attr(struct bitmap *bitmap, int pnum,
 802                                 enum bitmap_page_attr attr)
 803{
 804        set_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 805}
 806
 807static inline void clear_page_attr(struct bitmap *bitmap, int pnum,
 808                                   enum bitmap_page_attr attr)
 809{
 810        clear_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 811}
 812
 813static inline int test_page_attr(struct bitmap *bitmap, int pnum,
 814                                 enum bitmap_page_attr attr)
 815{
 816        return test_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 817}
 818
 819static inline int test_and_clear_page_attr(struct bitmap *bitmap, int pnum,
 820                                           enum bitmap_page_attr attr)
 821{
 822        return test_and_clear_bit((pnum<<2) + attr,
 823                                  bitmap->storage.filemap_attr);
 824}
 825/*
 826 * bitmap_file_set_bit -- called before performing a write to the md device
 827 * to set (and eventually sync) a particular bit in the bitmap file
 828 *
 829 * we set the bit immediately, then we record the page number so that
 830 * when an unplug occurs, we can flush the dirty pages out to disk
 831 */
 832static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 833{
 834        unsigned long bit;
 835        struct page *page;
 836        void *kaddr;
 837        unsigned long chunk = block >> bitmap->counts.chunkshift;
 838
 839        page = filemap_get_page(&bitmap->storage, chunk);
 840        if (!page)
 841                return;
 842        bit = file_page_offset(&bitmap->storage, chunk);
 843
 844        /* set the bit */
 845        kaddr = kmap_atomic(page);
 846        if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
 847                set_bit(bit, kaddr);
 848        else
 849                test_and_set_bit_le(bit, kaddr);
 850        kunmap_atomic(kaddr);
 851        pr_debug("set file bit %lu page %lu\n", bit, page->index);
 852        /* record page number so it gets flushed to disk when unplug occurs */
 853        set_page_attr(bitmap, page->index, BITMAP_PAGE_DIRTY);
 854}
 855
 856static void bitmap_file_clear_bit(struct bitmap *bitmap, sector_t block)
 857{
 858        unsigned long bit;
 859        struct page *page;
 860        void *paddr;
 861        unsigned long chunk = block >> bitmap->counts.chunkshift;
 862
 863        page = filemap_get_page(&bitmap->storage, chunk);
 864        if (!page)
 865                return;
 866        bit = file_page_offset(&bitmap->storage, chunk);
 867        paddr = kmap_atomic(page);
 868        if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
 869                clear_bit(bit, paddr);
 870        else
 871                test_and_clear_bit_le(bit, paddr);
 872        kunmap_atomic(paddr);
 873        if (!test_page_attr(bitmap, page->index, BITMAP_PAGE_NEEDWRITE)) {
 874                set_page_attr(bitmap, page->index, BITMAP_PAGE_PENDING);
 875                bitmap->allclean = 0;
 876        }
 877}
 878
 879/* this gets called when the md device is ready to unplug its underlying
 880 * (slave) device queues -- before we let any writes go down, we need to
 881 * sync the dirty pages of the bitmap file to disk */
 882void bitmap_unplug(struct bitmap *bitmap)
 883{
 884        unsigned long i;
 885        int dirty, need_write;
 886        int wait = 0;
 887
 888        if (!bitmap || !bitmap->storage.filemap ||
 889            test_bit(BITMAP_STALE, &bitmap->flags))
 890                return;
 891
 892        /* look at each page to see if there are any set bits that need to be
 893         * flushed out to disk */
 894        for (i = 0; i < bitmap->storage.file_pages; i++) {
 895                if (!bitmap->storage.filemap)
 896                        return;
 897                dirty = test_and_clear_page_attr(bitmap, i, BITMAP_PAGE_DIRTY);
 898                need_write = test_and_clear_page_attr(bitmap, i,
 899                                                      BITMAP_PAGE_NEEDWRITE);
 900                if (dirty || need_write) {
 901                        clear_page_attr(bitmap, i, BITMAP_PAGE_PENDING);
 902                        write_page(bitmap, bitmap->storage.filemap[i], 0);
 903                }
 904                if (dirty)
 905                        wait = 1;
 906        }
 907        if (wait) { /* if any writes were performed, we need to wait on them */
 908                if (bitmap->storage.file)
 909                        wait_event(bitmap->write_wait,
 910                                   atomic_read(&bitmap->pending_writes)==0);
 911                else
 912                        md_super_wait(bitmap->mddev);
 913        }
 914        if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
 915                bitmap_file_kick(bitmap);
 916}
 917EXPORT_SYMBOL(bitmap_unplug);
 918
 919static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
 920/* * bitmap_init_from_disk -- called at bitmap_create time to initialize
 921 * the in-memory bitmap from the on-disk bitmap -- also, sets up the
 922 * memory mapping of the bitmap file
 923 * Special cases:
 924 *   if there's no bitmap file, or if the bitmap file had been
 925 *   previously kicked from the array, we mark all the bits as
 926 *   1's in order to cause a full resync.
 927 *
 928 * We ignore all bits for sectors that end earlier than 'start'.
 929 * This is used when reading an out-of-date bitmap...
 930 */
 931static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
 932{
 933        unsigned long i, chunks, index, oldindex, bit;
 934        struct page *page = NULL;
 935        unsigned long bit_cnt = 0;
 936        struct file *file;
 937        unsigned long offset;
 938        int outofdate;
 939        int ret = -ENOSPC;
 940        void *paddr;
 941        struct bitmap_storage *store = &bitmap->storage;
 942
 943        chunks = bitmap->counts.chunks;
 944        file = store->file;
 945
 946        if (!file && !bitmap->mddev->bitmap_info.offset) {
 947                /* No permanent bitmap - fill with '1s'. */
 948                store->filemap = NULL;
 949                store->file_pages = 0;
 950                for (i = 0; i < chunks ; i++) {
 951                        /* if the disk bit is set, set the memory bit */
 952                        int needed = ((sector_t)(i+1) << (bitmap->counts.chunkshift)
 953                                      >= start);
 954                        bitmap_set_memory_bits(bitmap,
 955                                               (sector_t)i << bitmap->counts.chunkshift,
 956                                               needed);
 957                }
 958                return 0;
 959        }
 960
 961        outofdate = test_bit(BITMAP_STALE, &bitmap->flags);
 962        if (outofdate)
 963                printk(KERN_INFO "%s: bitmap file is out of date, doing full "
 964                        "recovery\n", bmname(bitmap));
 965
 966        if (file && i_size_read(file->f_mapping->host) < store->bytes) {
 967                printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
 968                       bmname(bitmap),
 969                       (unsigned long) i_size_read(file->f_mapping->host),
 970                       store->bytes);
 971                goto err;
 972        }
 973
 974        oldindex = ~0L;
 975        offset = 0;
 976        if (!bitmap->mddev->bitmap_info.external)
 977                offset = sizeof(bitmap_super_t);
 978
 979        for (i = 0; i < chunks; i++) {
 980                int b;
 981                index = file_page_index(&bitmap->storage, i);
 982                bit = file_page_offset(&bitmap->storage, i);
 983                if (index != oldindex) { /* this is a new page, read it in */
 984                        int count;
 985                        /* unmap the old page, we're done with it */
 986                        if (index == store->file_pages-1)
 987                                count = store->bytes - index * PAGE_SIZE;
 988                        else
 989                                count = PAGE_SIZE;
 990                        page = store->filemap[index];
 991                        if (file)
 992                                ret = read_page(file, index, bitmap,
 993                                                count, page);
 994                        else
 995                                ret = read_sb_page(
 996                                        bitmap->mddev,
 997                                        bitmap->mddev->bitmap_info.offset,
 998                                        page,
 999                                        index, count);
1000
1001                        if (ret)
1002                                goto err;
1003
1004                        oldindex = index;
1005
1006                        if (outofdate) {
1007                                /*
1008                                 * if bitmap is out of date, dirty the
1009                                 * whole page and write it out
1010                                 */
1011                                paddr = kmap_atomic(page);
1012                                memset(paddr + offset, 0xff,
1013                                       PAGE_SIZE - offset);
1014                                kunmap_atomic(paddr);
1015                                write_page(bitmap, page, 1);
1016
1017                                ret = -EIO;
1018                                if (test_bit(BITMAP_WRITE_ERROR,
1019                                             &bitmap->flags))
1020                                        goto err;
1021                        }
1022                }
1023                paddr = kmap_atomic(page);
1024                if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
1025                        b = test_bit(bit, paddr);
1026                else
1027                        b = test_bit_le(bit, paddr);
1028                kunmap_atomic(paddr);
1029                if (b) {
1030                        /* if the disk bit is set, set the memory bit */
1031                        int needed = ((sector_t)(i+1) << bitmap->counts.chunkshift
1032                                      >= start);
1033                        bitmap_set_memory_bits(bitmap,
1034                                               (sector_t)i << bitmap->counts.chunkshift,
1035                                               needed);
1036                        bit_cnt++;
1037                }
1038                offset = 0;
1039        }
1040
1041        printk(KERN_INFO "%s: bitmap initialized from disk: "
1042               "read %lu pages, set %lu of %lu bits\n",
1043               bmname(bitmap), store->file_pages,
1044               bit_cnt, chunks);
1045
1046        return 0;
1047
1048 err:
1049        printk(KERN_INFO "%s: bitmap initialisation failed: %d\n",
1050               bmname(bitmap), ret);
1051        return ret;
1052}
1053
1054void bitmap_write_all(struct bitmap *bitmap)
1055{
1056        /* We don't actually write all bitmap blocks here,
1057         * just flag them as needing to be written
1058         */
1059        int i;
1060
1061        if (!bitmap || !bitmap->storage.filemap)
1062                return;
1063        if (bitmap->storage.file)
1064                /* Only one copy, so nothing needed */
1065                return;
1066
1067        for (i = 0; i < bitmap->storage.file_pages; i++)
1068                set_page_attr(bitmap, i,
1069                              BITMAP_PAGE_NEEDWRITE);
1070        bitmap->allclean = 0;
1071}
1072
1073static void bitmap_count_page(struct bitmap_counts *bitmap,
1074                              sector_t offset, int inc)
1075{
1076        sector_t chunk = offset >> bitmap->chunkshift;
1077        unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1078        bitmap->bp[page].count += inc;
1079        bitmap_checkfree(bitmap, page);
1080}
1081
1082static void bitmap_set_pending(struct bitmap_counts *bitmap, sector_t offset)
1083{
1084        sector_t chunk = offset >> bitmap->chunkshift;
1085        unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1086        struct bitmap_page *bp = &bitmap->bp[page];
1087
1088        if (!bp->pending)
1089                bp->pending = 1;
1090}
1091
1092static bitmap_counter_t *bitmap_get_counter(struct bitmap_counts *bitmap,
1093                                            sector_t offset, sector_t *blocks,
1094                                            int create);
1095
1096/*
1097 * bitmap daemon -- periodically wakes up to clean bits and flush pages
1098 *                      out to disk
1099 */
1100
1101void bitmap_daemon_work(struct mddev *mddev)
1102{
1103        struct bitmap *bitmap;
1104        unsigned long j;
1105        unsigned long nextpage;
1106        sector_t blocks;
1107        struct bitmap_counts *counts;
1108
1109        /* Use a mutex to guard daemon_work against
1110         * bitmap_destroy.
1111         */
1112        mutex_lock(&mddev->bitmap_info.mutex);
1113        bitmap = mddev->bitmap;
1114        if (bitmap == NULL) {
1115                mutex_unlock(&mddev->bitmap_info.mutex);
1116                return;
1117        }
1118        if (time_before(jiffies, bitmap->daemon_lastrun
1119                        + mddev->bitmap_info.daemon_sleep))
1120                goto done;
1121
1122        bitmap->daemon_lastrun = jiffies;
1123        if (bitmap->allclean) {
1124                mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1125                goto done;
1126        }
1127        bitmap->allclean = 1;
1128
1129        /* Any file-page which is PENDING now needs to be written.
1130         * So set NEEDWRITE now, then after we make any last-minute changes
1131         * we will write it.
1132         */
1133        for (j = 0; j < bitmap->storage.file_pages; j++)
1134                if (test_and_clear_page_attr(bitmap, j,
1135                                             BITMAP_PAGE_PENDING))
1136                        set_page_attr(bitmap, j,
1137                                      BITMAP_PAGE_NEEDWRITE);
1138
1139        if (bitmap->need_sync &&
1140            mddev->bitmap_info.external == 0) {
1141                /* Arrange for superblock update as well as
1142                 * other changes */
1143                bitmap_super_t *sb;
1144                bitmap->need_sync = 0;
1145                if (bitmap->storage.filemap) {
1146                        sb = kmap_atomic(bitmap->storage.sb_page);
1147                        sb->events_cleared =
1148                                cpu_to_le64(bitmap->events_cleared);
1149                        kunmap_atomic(sb);
1150                        set_page_attr(bitmap, 0,
1151                                      BITMAP_PAGE_NEEDWRITE);
1152                }
1153        }
1154        /* Now look at the bitmap counters and if any are '2' or '1',
1155         * decrement and handle accordingly.
1156         */
1157        counts = &bitmap->counts;
1158        spin_lock_irq(&counts->lock);
1159        nextpage = 0;
1160        for (j = 0; j < counts->chunks; j++) {
1161                bitmap_counter_t *bmc;
1162                sector_t  block = (sector_t)j << counts->chunkshift;
1163
1164                if (j == nextpage) {
1165                        nextpage += PAGE_COUNTER_RATIO;
1166                        if (!counts->bp[j >> PAGE_COUNTER_SHIFT].pending) {
1167                                j |= PAGE_COUNTER_MASK;
1168                                continue;
1169                        }
1170                        counts->bp[j >> PAGE_COUNTER_SHIFT].pending = 0;
1171                }
1172                bmc = bitmap_get_counter(counts,
1173                                         block,
1174                                         &blocks, 0);
1175
1176                if (!bmc) {
1177                        j |= PAGE_COUNTER_MASK;
1178                        continue;
1179                }
1180                if (*bmc == 1 && !bitmap->need_sync) {
1181                        /* We can clear the bit */
1182                        *bmc = 0;
1183                        bitmap_count_page(counts, block, -1);
1184                        bitmap_file_clear_bit(bitmap, block);
1185                } else if (*bmc && *bmc <= 2) {
1186                        *bmc = 1;
1187                        bitmap_set_pending(counts, block);
1188                        bitmap->allclean = 0;
1189                }
1190        }
1191        spin_unlock_irq(&counts->lock);
1192
1193        /* Now start writeout on any page in NEEDWRITE that isn't DIRTY.
1194         * DIRTY pages need to be written by bitmap_unplug so it can wait
1195         * for them.
1196         * If we find any DIRTY page we stop there and let bitmap_unplug
1197         * handle all the rest.  This is important in the case where
1198         * the first blocking holds the superblock and it has been updated.
1199         * We mustn't write any other blocks before the superblock.
1200         */
1201        for (j = 0;
1202             j < bitmap->storage.file_pages
1203                     && !test_bit(BITMAP_STALE, &bitmap->flags);
1204             j++) {
1205
1206                if (test_page_attr(bitmap, j,
1207                                   BITMAP_PAGE_DIRTY))
1208                        /* bitmap_unplug will handle the rest */
1209                        break;
1210                if (test_and_clear_page_attr(bitmap, j,
1211                                             BITMAP_PAGE_NEEDWRITE)) {
1212                        write_page(bitmap, bitmap->storage.filemap[j], 0);
1213                }
1214        }
1215
1216 done:
1217        if (bitmap->allclean == 0)
1218                mddev->thread->timeout =
1219                        mddev->bitmap_info.daemon_sleep;
1220        mutex_unlock(&mddev->bitmap_info.mutex);
1221}
1222
1223static bitmap_counter_t *bitmap_get_counter(struct bitmap_counts *bitmap,
1224                                            sector_t offset, sector_t *blocks,
1225                                            int create)
1226__releases(bitmap->lock)
1227__acquires(bitmap->lock)
1228{
1229        /* If 'create', we might release the lock and reclaim it.
1230         * The lock must have been taken with interrupts enabled.
1231         * If !create, we don't release the lock.
1232         */
1233        sector_t chunk = offset >> bitmap->chunkshift;
1234        unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1235        unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1236        sector_t csize;
1237        int err;
1238
1239        err = bitmap_checkpage(bitmap, page, create);
1240
1241        if (bitmap->bp[page].hijacked ||
1242            bitmap->bp[page].map == NULL)
1243                csize = ((sector_t)1) << (bitmap->chunkshift +
1244                                          PAGE_COUNTER_SHIFT - 1);
1245        else
1246                csize = ((sector_t)1) << bitmap->chunkshift;
1247        *blocks = csize - (offset & (csize - 1));
1248
1249        if (err < 0)
1250                return NULL;
1251
1252        /* now locked ... */
1253
1254        if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1255                /* should we use the first or second counter field
1256                 * of the hijacked pointer? */
1257                int hi = (pageoff > PAGE_COUNTER_MASK);
1258                return  &((bitmap_counter_t *)
1259                          &bitmap->bp[page].map)[hi];
1260        } else /* page is allocated */
1261                return (bitmap_counter_t *)
1262                        &(bitmap->bp[page].map[pageoff]);
1263}
1264
1265int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1266{
1267        if (!bitmap)
1268                return 0;
1269
1270        if (behind) {
1271                int bw;
1272                atomic_inc(&bitmap->behind_writes);
1273                bw = atomic_read(&bitmap->behind_writes);
1274                if (bw > bitmap->behind_writes_used)
1275                        bitmap->behind_writes_used = bw;
1276
1277                pr_debug("inc write-behind count %d/%lu\n",
1278                         bw, bitmap->mddev->bitmap_info.max_write_behind);
1279        }
1280
1281        while (sectors) {
1282                sector_t blocks;
1283                bitmap_counter_t *bmc;
1284
1285                spin_lock_irq(&bitmap->counts.lock);
1286                bmc = bitmap_get_counter(&bitmap->counts, offset, &blocks, 1);
1287                if (!bmc) {
1288                        spin_unlock_irq(&bitmap->counts.lock);
1289                        return 0;
1290                }
1291
1292                if (unlikely(COUNTER(*bmc) == COUNTER_MAX)) {
1293                        DEFINE_WAIT(__wait);
1294                        /* note that it is safe to do the prepare_to_wait
1295                         * after the test as long as we do it before dropping
1296                         * the spinlock.
1297                         */
1298                        prepare_to_wait(&bitmap->overflow_wait, &__wait,
1299                                        TASK_UNINTERRUPTIBLE);
1300                        spin_unlock_irq(&bitmap->counts.lock);
1301                        schedule();
1302                        finish_wait(&bitmap->overflow_wait, &__wait);
1303                        continue;
1304                }
1305
1306                switch (*bmc) {
1307                case 0:
1308                        bitmap_file_set_bit(bitmap, offset);
1309                        bitmap_count_page(&bitmap->counts, offset, 1);
1310                        /* fall through */
1311                case 1:
1312                        *bmc = 2;
1313                }
1314
1315                (*bmc)++;
1316
1317                spin_unlock_irq(&bitmap->counts.lock);
1318
1319                offset += blocks;
1320                if (sectors > blocks)
1321                        sectors -= blocks;
1322                else
1323                        sectors = 0;
1324        }
1325        return 0;
1326}
1327EXPORT_SYMBOL(bitmap_startwrite);
1328
1329void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1330                     int success, int behind)
1331{
1332        if (!bitmap)
1333                return;
1334        if (behind) {
1335                if (atomic_dec_and_test(&bitmap->behind_writes))
1336                        wake_up(&bitmap->behind_wait);
1337                pr_debug("dec write-behind count %d/%lu\n",
1338                         atomic_read(&bitmap->behind_writes),
1339                         bitmap->mddev->bitmap_info.max_write_behind);
1340        }
1341
1342        while (sectors) {
1343                sector_t blocks;
1344                unsigned long flags;
1345                bitmap_counter_t *bmc;
1346
1347                spin_lock_irqsave(&bitmap->counts.lock, flags);
1348                bmc = bitmap_get_counter(&bitmap->counts, offset, &blocks, 0);
1349                if (!bmc) {
1350                        spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1351                        return;
1352                }
1353
1354                if (success && !bitmap->mddev->degraded &&
1355                    bitmap->events_cleared < bitmap->mddev->events) {
1356                        bitmap->events_cleared = bitmap->mddev->events;
1357                        bitmap->need_sync = 1;
1358                        sysfs_notify_dirent_safe(bitmap->sysfs_can_clear);
1359                }
1360
1361                if (!success && !NEEDED(*bmc))
1362                        *bmc |= NEEDED_MASK;
1363
1364                if (COUNTER(*bmc) == COUNTER_MAX)
1365                        wake_up(&bitmap->overflow_wait);
1366
1367                (*bmc)--;
1368                if (*bmc <= 2) {
1369                        bitmap_set_pending(&bitmap->counts, offset);
1370                        bitmap->allclean = 0;
1371                }
1372                spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1373                offset += blocks;
1374                if (sectors > blocks)
1375                        sectors -= blocks;
1376                else
1377                        sectors = 0;
1378        }
1379}
1380EXPORT_SYMBOL(bitmap_endwrite);
1381
1382static int __bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1383                               int degraded)
1384{
1385        bitmap_counter_t *bmc;
1386        int rv;
1387        if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1388                *blocks = 1024;
1389                return 1; /* always resync if no bitmap */
1390        }
1391        spin_lock_irq(&bitmap->counts.lock);
1392        bmc = bitmap_get_counter(&bitmap->counts, offset, blocks, 0);
1393        rv = 0;
1394        if (bmc) {
1395                /* locked */
1396                if (RESYNC(*bmc))
1397                        rv = 1;
1398                else if (NEEDED(*bmc)) {
1399                        rv = 1;
1400                        if (!degraded) { /* don't set/clear bits if degraded */
1401                                *bmc |= RESYNC_MASK;
1402                                *bmc &= ~NEEDED_MASK;
1403                        }
1404                }
1405        }
1406        spin_unlock_irq(&bitmap->counts.lock);
1407        return rv;
1408}
1409
1410int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1411                      int degraded)
1412{
1413        /* bitmap_start_sync must always report on multiples of whole
1414         * pages, otherwise resync (which is very PAGE_SIZE based) will
1415         * get confused.
1416         * So call __bitmap_start_sync repeatedly (if needed) until
1417         * At least PAGE_SIZE>>9 blocks are covered.
1418         * Return the 'or' of the result.
1419         */
1420        int rv = 0;
1421        sector_t blocks1;
1422
1423        *blocks = 0;
1424        while (*blocks < (PAGE_SIZE>>9)) {
1425                rv |= __bitmap_start_sync(bitmap, offset,
1426                                          &blocks1, degraded);
1427                offset += blocks1;
1428                *blocks += blocks1;
1429        }
1430        return rv;
1431}
1432EXPORT_SYMBOL(bitmap_start_sync);
1433
1434void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks, int aborted)
1435{
1436        bitmap_counter_t *bmc;
1437        unsigned long flags;
1438
1439        if (bitmap == NULL) {
1440                *blocks = 1024;
1441                return;
1442        }
1443        spin_lock_irqsave(&bitmap->counts.lock, flags);
1444        bmc = bitmap_get_counter(&bitmap->counts, offset, blocks, 0);
1445        if (bmc == NULL)
1446                goto unlock;
1447        /* locked */
1448        if (RESYNC(*bmc)) {
1449                *bmc &= ~RESYNC_MASK;
1450
1451                if (!NEEDED(*bmc) && aborted)
1452                        *bmc |= NEEDED_MASK;
1453                else {
1454                        if (*bmc <= 2) {
1455                                bitmap_set_pending(&bitmap->counts, offset);
1456                                bitmap->allclean = 0;
1457                        }
1458                }
1459        }
1460 unlock:
1461        spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1462}
1463EXPORT_SYMBOL(bitmap_end_sync);
1464
1465void bitmap_close_sync(struct bitmap *bitmap)
1466{
1467        /* Sync has finished, and any bitmap chunks that weren't synced
1468         * properly have been aborted.  It remains to us to clear the
1469         * RESYNC bit wherever it is still on
1470         */
1471        sector_t sector = 0;
1472        sector_t blocks;
1473        if (!bitmap)
1474                return;
1475        while (sector < bitmap->mddev->resync_max_sectors) {
1476                bitmap_end_sync(bitmap, sector, &blocks, 0);
1477                sector += blocks;
1478        }
1479}
1480EXPORT_SYMBOL(bitmap_close_sync);
1481
1482void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector)
1483{
1484        sector_t s = 0;
1485        sector_t blocks;
1486
1487        if (!bitmap)
1488                return;
1489        if (sector == 0) {
1490                bitmap->last_end_sync = jiffies;
1491                return;
1492        }
1493        if (time_before(jiffies, (bitmap->last_end_sync
1494                                  + bitmap->mddev->bitmap_info.daemon_sleep)))
1495                return;
1496        wait_event(bitmap->mddev->recovery_wait,
1497                   atomic_read(&bitmap->mddev->recovery_active) == 0);
1498
1499        bitmap->mddev->curr_resync_completed = sector;
1500        set_bit(MD_CHANGE_CLEAN, &bitmap->mddev->flags);
1501        sector &= ~((1ULL << bitmap->counts.chunkshift) - 1);
1502        s = 0;
1503        while (s < sector && s < bitmap->mddev->resync_max_sectors) {
1504                bitmap_end_sync(bitmap, s, &blocks, 0);
1505                s += blocks;
1506        }
1507        bitmap->last_end_sync = jiffies;
1508        sysfs_notify(&bitmap->mddev->kobj, NULL, "sync_completed");
1509}
1510EXPORT_SYMBOL(bitmap_cond_end_sync);
1511
1512static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1513{
1514        /* For each chunk covered by any of these sectors, set the
1515         * counter to 2 and possibly set resync_needed.  They should all
1516         * be 0 at this point
1517         */
1518
1519        sector_t secs;
1520        bitmap_counter_t *bmc;
1521        spin_lock_irq(&bitmap->counts.lock);
1522        bmc = bitmap_get_counter(&bitmap->counts, offset, &secs, 1);
1523        if (!bmc) {
1524                spin_unlock_irq(&bitmap->counts.lock);
1525                return;
1526        }
1527        if (!*bmc) {
1528                *bmc = 2 | (needed ? NEEDED_MASK : 0);
1529                bitmap_count_page(&bitmap->counts, offset, 1);
1530                bitmap_set_pending(&bitmap->counts, offset);
1531                bitmap->allclean = 0;
1532        }
1533        spin_unlock_irq(&bitmap->counts.lock);
1534}
1535
1536/* dirty the memory and file bits for bitmap chunks "s" to "e" */
1537void bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1538{
1539        unsigned long chunk;
1540
1541        for (chunk = s; chunk <= e; chunk++) {
1542                sector_t sec = (sector_t)chunk << bitmap->counts.chunkshift;
1543                bitmap_set_memory_bits(bitmap, sec, 1);
1544                bitmap_file_set_bit(bitmap, sec);
1545                if (sec < bitmap->mddev->recovery_cp)
1546                        /* We are asserting that the array is dirty,
1547                         * so move the recovery_cp address back so
1548                         * that it is obvious that it is dirty
1549                         */
1550                        bitmap->mddev->recovery_cp = sec;
1551        }
1552}
1553
1554/*
1555 * flush out any pending updates
1556 */
1557void bitmap_flush(struct mddev *mddev)
1558{
1559        struct bitmap *bitmap = mddev->bitmap;
1560        long sleep;
1561
1562        if (!bitmap) /* there was no bitmap */
1563                return;
1564
1565        /* run the daemon_work three time to ensure everything is flushed
1566         * that can be
1567         */
1568        sleep = mddev->bitmap_info.daemon_sleep * 2;
1569        bitmap->daemon_lastrun -= sleep;
1570        bitmap_daemon_work(mddev);
1571        bitmap->daemon_lastrun -= sleep;
1572        bitmap_daemon_work(mddev);
1573        bitmap->daemon_lastrun -= sleep;
1574        bitmap_daemon_work(mddev);
1575        bitmap_update_sb(bitmap);
1576}
1577
1578/*
1579 * free memory that was allocated
1580 */
1581static void bitmap_free(struct bitmap *bitmap)
1582{
1583        unsigned long k, pages;
1584        struct bitmap_page *bp;
1585
1586        if (!bitmap) /* there was no bitmap */
1587                return;
1588
1589        /* Shouldn't be needed - but just in case.... */
1590        wait_event(bitmap->write_wait,
1591                   atomic_read(&bitmap->pending_writes) == 0);
1592
1593        /* release the bitmap file  */
1594        bitmap_file_unmap(&bitmap->storage);
1595
1596        bp = bitmap->counts.bp;
1597        pages = bitmap->counts.pages;
1598
1599        /* free all allocated memory */
1600
1601        if (bp) /* deallocate the page memory */
1602                for (k = 0; k < pages; k++)
1603                        if (bp[k].map && !bp[k].hijacked)
1604                                kfree(bp[k].map);
1605        kfree(bp);
1606        kfree(bitmap);
1607}
1608
1609void bitmap_destroy(struct mddev *mddev)
1610{
1611        struct bitmap *bitmap = mddev->bitmap;
1612
1613        if (!bitmap) /* there was no bitmap */
1614                return;
1615
1616        mutex_lock(&mddev->bitmap_info.mutex);
1617        mddev->bitmap = NULL; /* disconnect from the md device */
1618        mutex_unlock(&mddev->bitmap_info.mutex);
1619        if (mddev->thread)
1620                mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1621
1622        if (bitmap->sysfs_can_clear)
1623                sysfs_put(bitmap->sysfs_can_clear);
1624
1625        bitmap_free(bitmap);
1626}
1627
1628/*
1629 * initialize the bitmap structure
1630 * if this returns an error, bitmap_destroy must be called to do clean up
1631 */
1632int bitmap_create(struct mddev *mddev)
1633{
1634        struct bitmap *bitmap;
1635        sector_t blocks = mddev->resync_max_sectors;
1636        struct file *file = mddev->bitmap_info.file;
1637        int err;
1638        struct sysfs_dirent *bm = NULL;
1639
1640        BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
1641
1642        BUG_ON(file && mddev->bitmap_info.offset);
1643
1644        bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1645        if (!bitmap)
1646                return -ENOMEM;
1647
1648        spin_lock_init(&bitmap->counts.lock);
1649        atomic_set(&bitmap->pending_writes, 0);
1650        init_waitqueue_head(&bitmap->write_wait);
1651        init_waitqueue_head(&bitmap->overflow_wait);
1652        init_waitqueue_head(&bitmap->behind_wait);
1653
1654        bitmap->mddev = mddev;
1655
1656        if (mddev->kobj.sd)
1657                bm = sysfs_get_dirent(mddev->kobj.sd, NULL, "bitmap");
1658        if (bm) {
1659                bitmap->sysfs_can_clear = sysfs_get_dirent(bm, NULL, "can_clear");
1660                sysfs_put(bm);
1661        } else
1662                bitmap->sysfs_can_clear = NULL;
1663
1664        bitmap->storage.file = file;
1665        if (file) {
1666                get_file(file);
1667                /* As future accesses to this file will use bmap,
1668                 * and bypass the page cache, we must sync the file
1669                 * first.
1670                 */
1671                vfs_fsync(file, 1);
1672        }
1673        /* read superblock from bitmap file (this sets mddev->bitmap_info.chunksize) */
1674        if (!mddev->bitmap_info.external) {
1675                /*
1676                 * If 'MD_ARRAY_FIRST_USE' is set, then device-mapper is
1677                 * instructing us to create a new on-disk bitmap instance.
1678                 */
1679                if (test_and_clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags))
1680                        err = bitmap_new_disk_sb(bitmap);
1681                else
1682                        err = bitmap_read_sb(bitmap);
1683        } else {
1684                err = 0;
1685                if (mddev->bitmap_info.chunksize == 0 ||
1686                    mddev->bitmap_info.daemon_sleep == 0)
1687                        /* chunksize and time_base need to be
1688                         * set first. */
1689                        err = -EINVAL;
1690        }
1691        if (err)
1692                goto error;
1693
1694        bitmap->daemon_lastrun = jiffies;
1695        err = bitmap_resize(bitmap, blocks, mddev->bitmap_info.chunksize, 1);
1696        if (err)
1697                goto error;
1698
1699        printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
1700               bitmap->counts.pages, bmname(bitmap));
1701
1702        mddev->bitmap = bitmap;
1703        return test_bit(BITMAP_WRITE_ERROR, &bitmap->flags) ? -EIO : 0;
1704
1705 error:
1706        bitmap_free(bitmap);
1707        return err;
1708}
1709
1710int bitmap_load(struct mddev *mddev)
1711{
1712        int err = 0;
1713        sector_t start = 0;
1714        sector_t sector = 0;
1715        struct bitmap *bitmap = mddev->bitmap;
1716
1717        if (!bitmap)
1718                goto out;
1719
1720        /* Clear out old bitmap info first:  Either there is none, or we
1721         * are resuming after someone else has possibly changed things,
1722         * so we should forget old cached info.
1723         * All chunks should be clean, but some might need_sync.
1724         */
1725        while (sector < mddev->resync_max_sectors) {
1726                sector_t blocks;
1727                bitmap_start_sync(bitmap, sector, &blocks, 0);
1728                sector += blocks;
1729        }
1730        bitmap_close_sync(bitmap);
1731
1732        if (mddev->degraded == 0
1733            || bitmap->events_cleared == mddev->events)
1734                /* no need to keep dirty bits to optimise a
1735                 * re-add of a missing device */
1736                start = mddev->recovery_cp;
1737
1738        mutex_lock(&mddev->bitmap_info.mutex);
1739        err = bitmap_init_from_disk(bitmap, start);
1740        mutex_unlock(&mddev->bitmap_info.mutex);
1741
1742        if (err)
1743                goto out;
1744        clear_bit(BITMAP_STALE, &bitmap->flags);
1745
1746        /* Kick recovery in case any bits were set */
1747        set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
1748
1749        mddev->thread->timeout = mddev->bitmap_info.daemon_sleep;
1750        md_wakeup_thread(mddev->thread);
1751
1752        bitmap_update_sb(bitmap);
1753
1754        if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
1755                err = -EIO;
1756out:
1757        return err;
1758}
1759EXPORT_SYMBOL_GPL(bitmap_load);
1760
1761void bitmap_status(struct seq_file *seq, struct bitmap *bitmap)
1762{
1763        unsigned long chunk_kb;
1764        struct bitmap_counts *counts;
1765
1766        if (!bitmap)
1767                return;
1768
1769        counts = &bitmap->counts;
1770
1771        chunk_kb = bitmap->mddev->bitmap_info.chunksize >> 10;
1772        seq_printf(seq, "bitmap: %lu/%lu pages [%luKB], "
1773                   "%lu%s chunk",
1774                   counts->pages - counts->missing_pages,
1775                   counts->pages,
1776                   (counts->pages - counts->missing_pages)
1777                   << (PAGE_SHIFT - 10),
1778                   chunk_kb ? chunk_kb : bitmap->mddev->bitmap_info.chunksize,
1779                   chunk_kb ? "KB" : "B");
1780        if (bitmap->storage.file) {
1781                seq_printf(seq, ", file: ");
1782                seq_path(seq, &bitmap->storage.file->f_path, " \t\n");
1783        }
1784
1785        seq_printf(seq, "\n");
1786}
1787
1788int bitmap_resize(struct bitmap *bitmap, sector_t blocks,
1789                  int chunksize, int init)
1790{
1791        /* If chunk_size is 0, choose an appropriate chunk size.
1792         * Then possibly allocate new storage space.
1793         * Then quiesce, copy bits, replace bitmap, and re-start
1794         *
1795         * This function is called both to set up the initial bitmap
1796         * and to resize the bitmap while the array is active.
1797         * If this happens as a result of the array being resized,
1798         * chunksize will be zero, and we need to choose a suitable
1799         * chunksize, otherwise we use what we are given.
1800         */
1801        struct bitmap_storage store;
1802        struct bitmap_counts old_counts;
1803        unsigned long chunks;
1804        sector_t block;
1805        sector_t old_blocks, new_blocks;
1806        int chunkshift;
1807        int ret = 0;
1808        long pages;
1809        struct bitmap_page *new_bp;
1810
1811        if (chunksize == 0) {
1812                /* If there is enough space, leave the chunk size unchanged,
1813                 * else increase by factor of two until there is enough space.
1814                 */
1815                long bytes;
1816                long space = bitmap->mddev->bitmap_info.space;
1817
1818                if (space == 0) {
1819                        /* We don't know how much space there is, so limit
1820                         * to current size - in sectors.
1821                         */
1822                        bytes = DIV_ROUND_UP(bitmap->counts.chunks, 8);
1823                        if (!bitmap->mddev->bitmap_info.external)
1824                                bytes += sizeof(bitmap_super_t);
1825                        space = DIV_ROUND_UP(bytes, 512);
1826                        bitmap->mddev->bitmap_info.space = space;
1827                }
1828                chunkshift = bitmap->counts.chunkshift;
1829                chunkshift--;
1830                do {
1831                        /* 'chunkshift' is shift from block size to chunk size */
1832                        chunkshift++;
1833                        chunks = DIV_ROUND_UP_SECTOR_T(blocks, 1 << chunkshift);
1834                        bytes = DIV_ROUND_UP(chunks, 8);
1835                        if (!bitmap->mddev->bitmap_info.external)
1836                                bytes += sizeof(bitmap_super_t);
1837                } while (bytes > (space << 9));
1838        } else
1839                chunkshift = ffz(~chunksize) - BITMAP_BLOCK_SHIFT;
1840
1841        chunks = DIV_ROUND_UP_SECTOR_T(blocks, 1 << chunkshift);
1842        memset(&store, 0, sizeof(store));
1843        if (bitmap->mddev->bitmap_info.offset || bitmap->mddev->bitmap_info.file)
1844                ret = bitmap_storage_alloc(&store, chunks,
1845                                           !bitmap->mddev->bitmap_info.external);
1846        if (ret)
1847                goto err;
1848
1849        pages = DIV_ROUND_UP(chunks, PAGE_COUNTER_RATIO);
1850
1851        new_bp = kzalloc(pages * sizeof(*new_bp), GFP_KERNEL);
1852        ret = -ENOMEM;
1853        if (!new_bp) {
1854                bitmap_file_unmap(&store);
1855                goto err;
1856        }
1857
1858        if (!init)
1859                bitmap->mddev->pers->quiesce(bitmap->mddev, 1);
1860
1861        store.file = bitmap->storage.file;
1862        bitmap->storage.file = NULL;
1863
1864        if (store.sb_page && bitmap->storage.sb_page)
1865                memcpy(page_address(store.sb_page),
1866                       page_address(bitmap->storage.sb_page),
1867                       sizeof(bitmap_super_t));
1868        bitmap_file_unmap(&bitmap->storage);
1869        bitmap->storage = store;
1870
1871        old_counts = bitmap->counts;
1872        bitmap->counts.bp = new_bp;
1873        bitmap->counts.pages = pages;
1874        bitmap->counts.missing_pages = pages;
1875        bitmap->counts.chunkshift = chunkshift;
1876        bitmap->counts.chunks = chunks;
1877        bitmap->mddev->bitmap_info.chunksize = 1 << (chunkshift +
1878                                                     BITMAP_BLOCK_SHIFT);
1879
1880        blocks = min(old_counts.chunks << old_counts.chunkshift,
1881                     chunks << chunkshift);
1882
1883        spin_lock_irq(&bitmap->counts.lock);
1884        for (block = 0; block < blocks; ) {
1885                bitmap_counter_t *bmc_old, *bmc_new;
1886                int set;
1887
1888                bmc_old = bitmap_get_counter(&old_counts, block,
1889                                             &old_blocks, 0);
1890                set = bmc_old && NEEDED(*bmc_old);
1891
1892                if (set) {
1893                        bmc_new = bitmap_get_counter(&bitmap->counts, block,
1894                                                     &new_blocks, 1);
1895                        if (*bmc_new == 0) {
1896                                /* need to set on-disk bits too. */
1897                                sector_t end = block + new_blocks;
1898                                sector_t start = block >> chunkshift;
1899                                start <<= chunkshift;
1900                                while (start < end) {
1901                                        bitmap_file_set_bit(bitmap, block);
1902                                        start += 1 << chunkshift;
1903                                }
1904                                *bmc_new = 2;
1905                                bitmap_count_page(&bitmap->counts,
1906                                                  block, 1);
1907                                bitmap_set_pending(&bitmap->counts,
1908                                                   block);
1909                        }
1910                        *bmc_new |= NEEDED_MASK;
1911                        if (new_blocks < old_blocks)
1912                                old_blocks = new_blocks;
1913                }
1914                block += old_blocks;
1915        }
1916
1917        if (!init) {
1918                int i;
1919                while (block < (chunks << chunkshift)) {
1920                        bitmap_counter_t *bmc;
1921                        bmc = bitmap_get_counter(&bitmap->counts, block,
1922                                                 &new_blocks, 1);
1923                        if (bmc) {
1924                                /* new space.  It needs to be resynced, so
1925                                 * we set NEEDED_MASK.
1926                                 */
1927                                if (*bmc == 0) {
1928                                        *bmc = NEEDED_MASK | 2;
1929                                        bitmap_count_page(&bitmap->counts,
1930                                                          block, 1);
1931                                        bitmap_set_pending(&bitmap->counts,
1932                                                           block);
1933                                }
1934                        }
1935                        block += new_blocks;
1936                }
1937                for (i = 0; i < bitmap->storage.file_pages; i++)
1938                        set_page_attr(bitmap, i, BITMAP_PAGE_DIRTY);
1939        }
1940        spin_unlock_irq(&bitmap->counts.lock);
1941
1942        if (!init) {
1943                bitmap_unplug(bitmap);
1944                bitmap->mddev->pers->quiesce(bitmap->mddev, 0);
1945        }
1946        ret = 0;
1947err:
1948        return ret;
1949}
1950EXPORT_SYMBOL_GPL(bitmap_resize);
1951
1952static ssize_t
1953location_show(struct mddev *mddev, char *page)
1954{
1955        ssize_t len;
1956        if (mddev->bitmap_info.file)
1957                len = sprintf(page, "file");
1958        else if (mddev->bitmap_info.offset)
1959                len = sprintf(page, "%+lld", (long long)mddev->bitmap_info.offset);
1960        else
1961                len = sprintf(page, "none");
1962        len += sprintf(page+len, "\n");
1963        return len;
1964}
1965
1966static ssize_t
1967location_store(struct mddev *mddev, const char *buf, size_t len)
1968{
1969
1970        if (mddev->pers) {
1971                if (!mddev->pers->quiesce)
1972                        return -EBUSY;
1973                if (mddev->recovery || mddev->sync_thread)
1974                        return -EBUSY;
1975        }
1976
1977        if (mddev->bitmap || mddev->bitmap_info.file ||
1978            mddev->bitmap_info.offset) {
1979                /* bitmap already configured.  Only option is to clear it */
1980                if (strncmp(buf, "none", 4) != 0)
1981                        return -EBUSY;
1982                if (mddev->pers) {
1983                        mddev->pers->quiesce(mddev, 1);
1984                        bitmap_destroy(mddev);
1985                        mddev->pers->quiesce(mddev, 0);
1986                }
1987                mddev->bitmap_info.offset = 0;
1988                if (mddev->bitmap_info.file) {
1989                        struct file *f = mddev->bitmap_info.file;
1990                        mddev->bitmap_info.file = NULL;
1991                        restore_bitmap_write_access(f);
1992                        fput(f);
1993                }
1994        } else {
1995                /* No bitmap, OK to set a location */
1996                long long offset;
1997                if (strncmp(buf, "none", 4) == 0)
1998                        /* nothing to be done */;
1999                else if (strncmp(buf, "file:", 5) == 0) {
2000                        /* Not supported yet */
2001                        return -EINVAL;
2002                } else {
2003                        int rv;
2004                        if (buf[0] == '+')
2005                                rv = strict_strtoll(buf+1, 10, &offset);
2006                        else
2007                                rv = strict_strtoll(buf, 10, &offset);
2008                        if (rv)
2009                                return rv;
2010                        if (offset == 0)
2011                                return -EINVAL;
2012                        if (mddev->bitmap_info.external == 0 &&
2013                            mddev->major_version == 0 &&
2014                            offset != mddev->bitmap_info.default_offset)
2015                                return -EINVAL;
2016                        mddev->bitmap_info.offset = offset;
2017                        if (mddev->pers) {
2018                                mddev->pers->quiesce(mddev, 1);
2019                                rv = bitmap_create(mddev);
2020                                if (!rv)
2021                                        rv = bitmap_load(mddev);
2022                                if (rv) {
2023                                        bitmap_destroy(mddev);
2024                                        mddev->bitmap_info.offset = 0;
2025                                }
2026                                mddev->pers->quiesce(mddev, 0);
2027                                if (rv)
2028                                        return rv;
2029                        }
2030                }
2031        }
2032        if (!mddev->external) {
2033                /* Ensure new bitmap info is stored in
2034                 * metadata promptly.
2035                 */
2036                set_bit(MD_CHANGE_DEVS, &mddev->flags);
2037                md_wakeup_thread(mddev->thread);
2038        }
2039        return len;
2040}
2041
2042static struct md_sysfs_entry bitmap_location =
2043__ATTR(location, S_IRUGO|S_IWUSR, location_show, location_store);
2044
2045/* 'bitmap/space' is the space available at 'location' for the
2046 * bitmap.  This allows the kernel to know when it is safe to
2047 * resize the bitmap to match a resized array.
2048 */
2049static ssize_t
2050space_show(struct mddev *mddev, char *page)
2051{
2052        return sprintf(page, "%lu\n", mddev->bitmap_info.space);
2053}
2054
2055static ssize_t
2056space_store(struct mddev *mddev, const char *buf, size_t len)
2057{
2058        unsigned long sectors;
2059        int rv;
2060
2061        rv = kstrtoul(buf, 10, &sectors);
2062        if (rv)
2063                return rv;
2064
2065        if (sectors == 0)
2066                return -EINVAL;
2067
2068        if (mddev->bitmap &&
2069            sectors < (mddev->bitmap->storage.bytes + 511) >> 9)
2070                return -EFBIG; /* Bitmap is too big for this small space */
2071
2072        /* could make sure it isn't too big, but that isn't really
2073         * needed - user-space should be careful.
2074         */
2075        mddev->bitmap_info.space = sectors;
2076        return len;
2077}
2078
2079static struct md_sysfs_entry bitmap_space =
2080__ATTR(space, S_IRUGO|S_IWUSR, space_show, space_store);
2081
2082static ssize_t
2083timeout_show(struct mddev *mddev, char *page)
2084{
2085        ssize_t len;
2086        unsigned long secs = mddev->bitmap_info.daemon_sleep / HZ;
2087        unsigned long jifs = mddev->bitmap_info.daemon_sleep % HZ;
2088
2089        len = sprintf(page, "%lu", secs);
2090        if (jifs)
2091                len += sprintf(page+len, ".%03u", jiffies_to_msecs(jifs));
2092        len += sprintf(page+len, "\n");
2093        return len;
2094}
2095
2096static ssize_t
2097timeout_store(struct mddev *mddev, const char *buf, size_t len)
2098{
2099        /* timeout can be set at any time */
2100        unsigned long timeout;
2101        int rv = strict_strtoul_scaled(buf, &timeout, 4);
2102        if (rv)
2103                return rv;
2104
2105        /* just to make sure we don't overflow... */
2106        if (timeout >= LONG_MAX / HZ)
2107                return -EINVAL;
2108
2109        timeout = timeout * HZ / 10000;
2110
2111        if (timeout >= MAX_SCHEDULE_TIMEOUT)
2112                timeout = MAX_SCHEDULE_TIMEOUT-1;
2113        if (timeout < 1)
2114                timeout = 1;
2115        mddev->bitmap_info.daemon_sleep = timeout;
2116        if (mddev->thread) {
2117                /* if thread->timeout is MAX_SCHEDULE_TIMEOUT, then
2118                 * the bitmap is all clean and we don't need to
2119                 * adjust the timeout right now
2120                 */
2121                if (mddev->thread->timeout < MAX_SCHEDULE_TIMEOUT) {
2122                        mddev->thread->timeout = timeout;
2123                        md_wakeup_thread(mddev->thread);
2124                }
2125        }
2126        return len;
2127}
2128
2129static struct md_sysfs_entry bitmap_timeout =
2130__ATTR(time_base, S_IRUGO|S_IWUSR, timeout_show, timeout_store);
2131
2132static ssize_t
2133backlog_show(struct mddev *mddev, char *page)
2134{
2135        return sprintf(page, "%lu\n", mddev->bitmap_info.max_write_behind);
2136}
2137
2138static ssize_t
2139backlog_store(struct mddev *mddev, const char *buf, size_t len)
2140{
2141        unsigned long backlog;
2142        int rv = strict_strtoul(buf, 10, &backlog);
2143        if (rv)
2144                return rv;
2145        if (backlog > COUNTER_MAX)
2146                return -EINVAL;
2147        mddev->bitmap_info.max_write_behind = backlog;
2148        return len;
2149}
2150
2151static struct md_sysfs_entry bitmap_backlog =
2152__ATTR(backlog, S_IRUGO|S_IWUSR, backlog_show, backlog_store);
2153
2154static ssize_t
2155chunksize_show(struct mddev *mddev, char *page)
2156{
2157        return sprintf(page, "%lu\n", mddev->bitmap_info.chunksize);
2158}
2159
2160static ssize_t
2161chunksize_store(struct mddev *mddev, const char *buf, size_t len)
2162{
2163        /* Can only be changed when no bitmap is active */
2164        int rv;
2165        unsigned long csize;
2166        if (mddev->bitmap)
2167                return -EBUSY;
2168        rv = strict_strtoul(buf, 10, &csize);
2169        if (rv)
2170                return rv;
2171        if (csize < 512 ||
2172            !is_power_of_2(csize))
2173                return -EINVAL;
2174        mddev->bitmap_info.chunksize = csize;
2175        return len;
2176}
2177
2178static struct md_sysfs_entry bitmap_chunksize =
2179__ATTR(chunksize, S_IRUGO|S_IWUSR, chunksize_show, chunksize_store);
2180
2181static ssize_t metadata_show(struct mddev *mddev, char *page)
2182{
2183        return sprintf(page, "%s\n", (mddev->bitmap_info.external
2184                                      ? "external" : "internal"));
2185}
2186
2187static ssize_t metadata_store(struct mddev *mddev, const char *buf, size_t len)
2188{
2189        if (mddev->bitmap ||
2190            mddev->bitmap_info.file ||
2191            mddev->bitmap_info.offset)
2192                return -EBUSY;
2193        if (strncmp(buf, "external", 8) == 0)
2194                mddev->bitmap_info.external = 1;
2195        else if (strncmp(buf, "internal", 8) == 0)
2196                mddev->bitmap_info.external = 0;
2197        else
2198                return -EINVAL;
2199        return len;
2200}
2201
2202static struct md_sysfs_entry bitmap_metadata =
2203__ATTR(metadata, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
2204
2205static ssize_t can_clear_show(struct mddev *mddev, char *page)
2206{
2207        int len;
2208        if (mddev->bitmap)
2209                len = sprintf(page, "%s\n", (mddev->bitmap->need_sync ?
2210                                             "false" : "true"));
2211        else
2212                len = sprintf(page, "\n");
2213        return len;
2214}
2215
2216static ssize_t can_clear_store(struct mddev *mddev, const char *buf, size_t len)
2217{
2218        if (mddev->bitmap == NULL)
2219                return -ENOENT;
2220        if (strncmp(buf, "false", 5) == 0)
2221                mddev->bitmap->need_sync = 1;
2222        else if (strncmp(buf, "true", 4) == 0) {
2223                if (mddev->degraded)
2224                        return -EBUSY;
2225                mddev->bitmap->need_sync = 0;
2226        } else
2227                return -EINVAL;
2228        return len;
2229}
2230
2231static struct md_sysfs_entry bitmap_can_clear =
2232__ATTR(can_clear, S_IRUGO|S_IWUSR, can_clear_show, can_clear_store);
2233
2234static ssize_t
2235behind_writes_used_show(struct mddev *mddev, char *page)
2236{
2237        if (mddev->bitmap == NULL)
2238                return sprintf(page, "0\n");
2239        return sprintf(page, "%lu\n",
2240                       mddev->bitmap->behind_writes_used);
2241}
2242
2243static ssize_t
2244behind_writes_used_reset(struct mddev *mddev, const char *buf, size_t len)
2245{
2246        if (mddev->bitmap)
2247                mddev->bitmap->behind_writes_used = 0;
2248        return len;
2249}
2250
2251static struct md_sysfs_entry max_backlog_used =
2252__ATTR(max_backlog_used, S_IRUGO | S_IWUSR,
2253       behind_writes_used_show, behind_writes_used_reset);
2254
2255static struct attribute *md_bitmap_attrs[] = {
2256        &bitmap_location.attr,
2257        &bitmap_space.attr,
2258        &bitmap_timeout.attr,
2259        &bitmap_backlog.attr,
2260        &bitmap_chunksize.attr,
2261        &bitmap_metadata.attr,
2262        &bitmap_can_clear.attr,
2263        &max_backlog_used.attr,
2264        NULL
2265};
2266struct attribute_group md_bitmap_group = {
2267        .name = "bitmap",
2268        .attrs = md_bitmap_attrs,
2269};
2270
2271
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