md: Don't read past end of bitmap when reading bitmap.
[safe/jmp/linux-2.6] / drivers / md / bitmap.c
index ae94f3b..ab7c8e4 100644 (file)
@@ -203,48 +203,36 @@ static void bitmap_checkfree(struct bitmap *bitmap, unsigned long page)
  * bitmap file handling - read and write the bitmap file and its superblock
  */
 
-/* copy the pathname of a file to a buffer */
-char *file_path(struct file *file, char *buf, int count)
-{
-       struct dentry *d;
-       struct vfsmount *v;
-
-       if (!buf)
-               return NULL;
-
-       d = file->f_path.dentry;
-       v = file->f_path.mnt;
-
-       buf = d_path(d, v, buf, count);
-
-       return IS_ERR(buf) ? NULL : buf;
-}
-
 /*
  * basic page I/O operations
  */
 
 /* IO operations when bitmap is stored near all superblocks */
-static struct page *read_sb_page(mddev_t *mddev, long offset, unsigned long index)
+static struct page *read_sb_page(mddev_t *mddev, long offset,
+                                struct page *page,
+                                unsigned long index, int size)
 {
        /* choose a good rdev and read the page from there */
 
        mdk_rdev_t *rdev;
        struct list_head *tmp;
-       struct page *page = alloc_page(GFP_KERNEL);
        sector_t target;
 
        if (!page)
+               page = alloc_page(GFP_KERNEL);
+       if (!page)
                return ERR_PTR(-ENOMEM);
 
-       ITERATE_RDEV(mddev, rdev, tmp) {
+       rdev_for_each(rdev, tmp, mddev) {
                if (! test_bit(In_sync, &rdev->flags)
                    || test_bit(Faulty, &rdev->flags))
                        continue;
 
-               target = (rdev->sb_offset << 1) + offset + index * (PAGE_SIZE/512);
+               target = rdev->sb_start + offset + index * (PAGE_SIZE/512);
 
-               if (sync_page_io(rdev->bdev, target, PAGE_SIZE, page, READ)) {
+               if (sync_page_io(rdev->bdev, target,
+                                roundup(size, bdev_hardsect_size(rdev->bdev)),
+                                page, READ)) {
                        page->index = index;
                        attach_page_buffers(page, NULL); /* so that free_buffer will
                                                          * quietly no-op */
@@ -255,15 +243,47 @@ static struct page *read_sb_page(mddev_t *mddev, long offset, unsigned long inde
 
 }
 
+static mdk_rdev_t *next_active_rdev(mdk_rdev_t *rdev, mddev_t *mddev)
+{
+       /* Iterate the disks of an mddev, using rcu to protect access to the
+        * linked list, and raising the refcount of devices we return to ensure
+        * they don't disappear while in use.
+        * As devices are only added or removed when raid_disk is < 0 and
+        * nr_pending is 0 and In_sync is clear, the entries we return will
+        * still be in the same position on the list when we re-enter
+        * list_for_each_continue_rcu.
+        */
+       struct list_head *pos;
+       rcu_read_lock();
+       if (rdev == NULL)
+               /* start at the beginning */
+               pos = &mddev->disks;
+       else {
+               /* release the previous rdev and start from there. */
+               rdev_dec_pending(rdev, mddev);
+               pos = &rdev->same_set;
+       }
+       list_for_each_continue_rcu(pos, &mddev->disks) {
+               rdev = list_entry(pos, mdk_rdev_t, same_set);
+               if (rdev->raid_disk >= 0 &&
+                   test_bit(In_sync, &rdev->flags) &&
+                   !test_bit(Faulty, &rdev->flags)) {
+                       /* this is a usable devices */
+                       atomic_inc(&rdev->nr_pending);
+                       rcu_read_unlock();
+                       return rdev;
+               }
+       }
+       rcu_read_unlock();
+       return NULL;
+}
+
 static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
 {
-       mdk_rdev_t *rdev;
-       struct list_head *tmp;
+       mdk_rdev_t *rdev = NULL;
        mddev_t *mddev = bitmap->mddev;
 
-       ITERATE_RDEV(mddev, rdev, tmp)
-               if (test_bit(In_sync, &rdev->flags)
-                   && !test_bit(Faulty, &rdev->flags)) {
+       while ((rdev = next_active_rdev(rdev, mddev)) != NULL) {
                        int size = PAGE_SIZE;
                        if (page->index == bitmap->file_pages-1)
                                size = roundup(bitmap->last_page_size,
@@ -274,41 +294,46 @@ static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
                        if (bitmap->offset < 0) {
                                /* DATA  BITMAP METADATA  */
                                if (bitmap->offset
-                                   + page->index * (PAGE_SIZE/512)
+                                   + (long)(page->index * (PAGE_SIZE/512))
                                    + size/512 > 0)
                                        /* bitmap runs in to metadata */
-                                       return -EINVAL;
+                                       goto bad_alignment;
                                if (rdev->data_offset + mddev->size*2
-                                   > rdev->sb_offset*2 + bitmap->offset)
+                                   > rdev->sb_start + bitmap->offset)
                                        /* data runs in to bitmap */
-                                       return -EINVAL;
-                       } else if (rdev->sb_offset*2 < rdev->data_offset) {
+                                       goto bad_alignment;
+                       } else if (rdev->sb_start < rdev->data_offset) {
                                /* METADATA BITMAP DATA */
-                               if (rdev->sb_offset*2
+                               if (rdev->sb_start
                                    + bitmap->offset
                                    + page->index*(PAGE_SIZE/512) + size/512
                                    > rdev->data_offset)
                                        /* bitmap runs in to data */
-                                       return -EINVAL;
+                                       goto bad_alignment;
                        } else {
                                /* DATA METADATA BITMAP - no problems */
                        }
                        md_super_write(mddev, rdev,
-                                      (rdev->sb_offset<<1) + bitmap->offset
+                                      rdev->sb_start + bitmap->offset
                                       + page->index * (PAGE_SIZE/512),
                                       size,
                                       page);
-               }
+       }
 
        if (wait)
                md_super_wait(mddev);
        return 0;
+
+ bad_alignment:
+       rcu_read_unlock();
+       return -EINVAL;
 }
 
+static void bitmap_file_kick(struct bitmap *bitmap);
 /*
  * write out a page to a file
  */
-static int write_page(struct bitmap *bitmap, struct page *page, int wait)
+static void write_page(struct bitmap *bitmap, struct page *page, int wait)
 {
        struct buffer_head *bh;
 
@@ -316,27 +341,26 @@ static int write_page(struct bitmap *bitmap, struct page *page, int wait)
                switch (write_sb_page(bitmap, page, wait)) {
                case -EINVAL:
                        bitmap->flags |= BITMAP_WRITE_ERROR;
-                       return -EIO;
                }
-               return 0;
-       }
+       } else {
 
-       bh = page_buffers(page);
+               bh = page_buffers(page);
 
-       while (bh && bh->b_blocknr) {
-               atomic_inc(&bitmap->pending_writes);
-               set_buffer_locked(bh);
-               set_buffer_mapped(bh);
-               submit_bh(WRITE, bh);
-               bh = bh->b_this_page;
-       }
+               while (bh && bh->b_blocknr) {
+                       atomic_inc(&bitmap->pending_writes);
+                       set_buffer_locked(bh);
+                       set_buffer_mapped(bh);
+                       submit_bh(WRITE, bh);
+                       bh = bh->b_this_page;
+               }
 
-       if (wait) {
-               wait_event(bitmap->write_wait,
-                          atomic_read(&bitmap->pending_writes)==0);
-               return (bitmap->flags & BITMAP_WRITE_ERROR) ? -EIO : 0;
+               if (wait) {
+                       wait_event(bitmap->write_wait,
+                                  atomic_read(&bitmap->pending_writes)==0);
+               }
        }
-       return 0;
+       if (bitmap->flags & BITMAP_WRITE_ERROR)
+               bitmap_file_kick(bitmap);
 }
 
 static void end_bitmap_write(struct buffer_head *bh, int uptodate)
@@ -456,25 +480,28 @@ out:
  */
 
 /* update the event counter and sync the superblock to disk */
-int bitmap_update_sb(struct bitmap *bitmap)
+void bitmap_update_sb(struct bitmap *bitmap)
 {
        bitmap_super_t *sb;
        unsigned long flags;
 
        if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
-               return 0;
+               return;
        spin_lock_irqsave(&bitmap->lock, flags);
        if (!bitmap->sb_page) { /* no superblock */
                spin_unlock_irqrestore(&bitmap->lock, flags);
-               return 0;
+               return;
        }
        spin_unlock_irqrestore(&bitmap->lock, flags);
        sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
        sb->events = cpu_to_le64(bitmap->mddev->events);
-       if (!bitmap->mddev->degraded)
-               sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
+       if (bitmap->mddev->events < bitmap->events_cleared) {
+               /* rocking back to read-only */
+               bitmap->events_cleared = bitmap->mddev->events;
+               sb->events_cleared = cpu_to_le64(bitmap->events_cleared);
+       }
        kunmap_atomic(sb, KM_USER0);
-       return write_page(bitmap, bitmap->sb_page, 1);
+       write_page(bitmap, bitmap->sb_page, 1);
 }
 
 /* print out the bitmap file superblock */
@@ -522,7 +549,9 @@ static int bitmap_read_sb(struct bitmap *bitmap)
 
                bitmap->sb_page = read_page(bitmap->file, 0, bitmap, bytes);
        } else {
-               bitmap->sb_page = read_sb_page(bitmap->mddev, bitmap->offset, 0);
+               bitmap->sb_page = read_sb_page(bitmap->mddev, bitmap->offset,
+                                              NULL,
+                                              0, sizeof(bitmap_super_t));
        }
        if (IS_ERR(bitmap->sb_page)) {
                err = PTR_ERR(bitmap->sb_page);
@@ -603,20 +632,22 @@ enum bitmap_mask_op {
        MASK_UNSET
 };
 
-/* record the state of the bitmap in the superblock */
-static void bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
-                               enum bitmap_mask_op op)
+/* record the state of the bitmap in the superblock.  Return the old value */
+static int bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
+                            enum bitmap_mask_op op)
 {
        bitmap_super_t *sb;
        unsigned long flags;
+       int old;
 
        spin_lock_irqsave(&bitmap->lock, flags);
        if (!bitmap->sb_page) { /* can't set the state */
                spin_unlock_irqrestore(&bitmap->lock, flags);
-               return;
+               return 0;
        }
        spin_unlock_irqrestore(&bitmap->lock, flags);
        sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
+       old = le32_to_cpu(sb->state) & bits;
        switch (op) {
                case MASK_SET: sb->state |= cpu_to_le32(bits);
                                break;
@@ -625,6 +656,7 @@ static void bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
                default: BUG();
        }
        kunmap_atomic(sb, KM_USER0);
+       return old;
 }
 
 /*
@@ -718,18 +750,25 @@ static void bitmap_file_kick(struct bitmap *bitmap)
 {
        char *path, *ptr = NULL;
 
-       bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET);
-       bitmap_update_sb(bitmap);
+       if (bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET) == 0) {
+               bitmap_update_sb(bitmap);
 
-       if (bitmap->file) {
-               path = kmalloc(PAGE_SIZE, GFP_KERNEL);
-               if (path)
-                       ptr = file_path(bitmap->file, path, PAGE_SIZE);
+               if (bitmap->file) {
+                       path = kmalloc(PAGE_SIZE, GFP_KERNEL);
+                       if (path)
+                               ptr = d_path(&bitmap->file->f_path, path,
+                                            PAGE_SIZE);
 
-               printk(KERN_ALERT "%s: kicking failed bitmap file %s from array!\n",
-                      bmname(bitmap), ptr ? ptr : "");
 
-               kfree(path);
+                       printk(KERN_ALERT
+                             "%s: kicking failed bitmap file %s from array!\n",
+                             bmname(bitmap), IS_ERR(ptr) ? "" : ptr);
+
+                       kfree(path);
+               } else
+                       printk(KERN_ALERT
+                              "%s: disabling internal bitmap due to errors\n",
+                              bmname(bitmap));
        }
 
        bitmap_file_put(bitmap);
@@ -800,16 +839,15 @@ static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 /* this gets called when the md device is ready to unplug its underlying
  * (slave) device queues -- before we let any writes go down, we need to
  * sync the dirty pages of the bitmap file to disk */
-int bitmap_unplug(struct bitmap *bitmap)
+void bitmap_unplug(struct bitmap *bitmap)
 {
        unsigned long i, flags;
        int dirty, need_write;
        struct page *page;
        int wait = 0;
-       int err;
 
        if (!bitmap)
-               return 0;
+               return;
 
        /* look at each page to see if there are any set bits that need to be
         * flushed out to disk */
@@ -817,7 +855,7 @@ int bitmap_unplug(struct bitmap *bitmap)
                spin_lock_irqsave(&bitmap->lock, flags);
                if (!bitmap->filemap) {
                        spin_unlock_irqrestore(&bitmap->lock, flags);
-                       return 0;
+                       return;
                }
                page = bitmap->filemap[i];
                dirty = test_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
@@ -829,7 +867,7 @@ int bitmap_unplug(struct bitmap *bitmap)
                spin_unlock_irqrestore(&bitmap->lock, flags);
 
                if (dirty | need_write)
-                       err = write_page(bitmap, page, 0);
+                       write_page(bitmap, page, 0);
        }
        if (wait) { /* if any writes were performed, we need to wait on them */
                if (bitmap->file)
@@ -840,7 +878,6 @@ int bitmap_unplug(struct bitmap *bitmap)
        }
        if (bitmap->flags & BITMAP_WRITE_ERROR)
                bitmap_file_kick(bitmap);
-       return 0;
 }
 
 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
@@ -889,21 +926,21 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
                        bmname(bitmap),
                        (unsigned long) i_size_read(file->f_mapping->host),
                        bytes + sizeof(bitmap_super_t));
-               goto out;
+               goto err;
        }
 
        ret = -ENOMEM;
 
        bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
        if (!bitmap->filemap)
-               goto out;
+               goto err;
 
        /* We need 4 bits per page, rounded up to a multiple of sizeof(unsigned long) */
        bitmap->filemap_attr = kzalloc(
                roundup( DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
                GFP_KERNEL);
        if (!bitmap->filemap_attr)
-               goto out;
+               goto err;
 
        oldindex = ~0L;
 
@@ -927,16 +964,21 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
                                 */
                                page = bitmap->sb_page;
                                offset = sizeof(bitmap_super_t);
+                               read_sb_page(bitmap->mddev, bitmap->offset,
+                                            page,
+                                            index, count);
                        } else if (file) {
                                page = read_page(file, index, bitmap, count);
                                offset = 0;
                        } else {
-                               page = read_sb_page(bitmap->mddev, bitmap->offset, index);
+                               page = read_sb_page(bitmap->mddev, bitmap->offset,
+                                                   NULL,
+                                                   index, count);
                                offset = 0;
                        }
                        if (IS_ERR(page)) { /* read error */
                                ret = PTR_ERR(page);
-                               goto out;
+                               goto err;
                        }
 
                        oldindex = index;
@@ -951,11 +993,13 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
                                memset(paddr + offset, 0xff,
                                       PAGE_SIZE - offset);
                                kunmap_atomic(paddr, KM_USER0);
-                               ret = write_page(bitmap, page, 1);
-                               if (ret) {
+                               write_page(bitmap, page, 1);
+
+                               ret = -EIO;
+                               if (bitmap->flags & BITMAP_WRITE_ERROR) {
                                        /* release, page not in filemap yet */
                                        put_page(page);
-                                       goto out;
+                                       goto err;
                                }
                        }
 
@@ -987,11 +1031,15 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
                md_wakeup_thread(bitmap->mddev->thread);
        }
 
-out:
        printk(KERN_INFO "%s: bitmap initialized from disk: "
-               "read %lu/%lu pages, set %lu bits, status: %d\n",
-               bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt, ret);
+               "read %lu/%lu pages, set %lu bits\n",
+               bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt);
+
+       return 0;
 
+ err:
+       printk(KERN_INFO "%s: bitmap initialisation failed: %d\n",
+              bmname(bitmap), ret);
        return ret;
 }
 
@@ -1028,20 +1076,25 @@ static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
  *                     out to disk
  */
 
-int bitmap_daemon_work(struct bitmap *bitmap)
+void bitmap_daemon_work(struct bitmap *bitmap)
 {
        unsigned long j;
        unsigned long flags;
        struct page *page = NULL, *lastpage = NULL;
-       int err = 0;
        int blocks;
        void *paddr;
 
        if (bitmap == NULL)
-               return 0;
+               return;
        if (time_before(jiffies, bitmap->daemon_lastrun + bitmap->daemon_sleep*HZ))
-               return 0;
+               goto done;
+
        bitmap->daemon_lastrun = jiffies;
+       if (bitmap->allclean) {
+               bitmap->mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
+               return;
+       }
+       bitmap->allclean = 1;
 
        for (j = 0; j < bitmap->chunks; j++) {
                bitmap_counter_t *bmc;
@@ -1064,12 +1117,8 @@ int bitmap_daemon_work(struct bitmap *bitmap)
 
                                spin_unlock_irqrestore(&bitmap->lock, flags);
                                if (need_write) {
-                                       switch (write_page(bitmap, page, 0)) {
-                                       case 0:
-                                               break;
-                                       default:
-                                               bitmap_file_kick(bitmap);
-                                       }
+                                       write_page(bitmap, page, 0);
+                                       bitmap->allclean = 0;
                                }
                                continue;
                        }
@@ -1079,19 +1128,27 @@ int bitmap_daemon_work(struct bitmap *bitmap)
                                if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
                                        clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
                                        spin_unlock_irqrestore(&bitmap->lock, flags);
-                                       err = write_page(bitmap, lastpage, 0);
+                                       write_page(bitmap, lastpage, 0);
                                } else {
                                        set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
                                        spin_unlock_irqrestore(&bitmap->lock, flags);
                                }
-                               if (err)
-                                       bitmap_file_kick(bitmap);
                        } else
                                spin_unlock_irqrestore(&bitmap->lock, flags);
                        lastpage = page;
-/*
-                       printk("bitmap clean at page %lu\n", j);
-*/
+
+                       /* We are possibly going to clear some bits, so make
+                        * sure that events_cleared is up-to-date.
+                        */
+                       if (bitmap->need_sync) {
+                               bitmap_super_t *sb;
+                               bitmap->need_sync = 0;
+                               sb = kmap_atomic(bitmap->sb_page, KM_USER0);
+                               sb->events_cleared =
+                                       cpu_to_le64(bitmap->events_cleared);
+                               kunmap_atomic(sb, KM_USER0);
+                               write_page(bitmap, bitmap->sb_page, 1);
+                       }
                        spin_lock_irqsave(&bitmap->lock, flags);
                        clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
                }
@@ -1101,6 +1158,9 @@ int bitmap_daemon_work(struct bitmap *bitmap)
 /*
   if (j < 100) printk("bitmap: j=%lu, *bmc = 0x%x\n", j, *bmc);
 */
+                       if (*bmc)
+                               bitmap->allclean = 0;
+
                        if (*bmc == 2) {
                                *bmc=1; /* maybe clear the bit next time */
                                set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
@@ -1128,14 +1188,16 @@ int bitmap_daemon_work(struct bitmap *bitmap)
                if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
                        clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
                        spin_unlock_irqrestore(&bitmap->lock, flags);
-                       err = write_page(bitmap, lastpage, 0);
+                       write_page(bitmap, lastpage, 0);
                } else {
                        set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
                        spin_unlock_irqrestore(&bitmap->lock, flags);
                }
        }
 
-       return err;
+ done:
+       if (bitmap->allclean == 0)
+               bitmap->mddev->thread->timeout = bitmap->daemon_sleep * HZ;
 }
 
 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
@@ -1205,8 +1267,7 @@ int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sect
                        prepare_to_wait(&bitmap->overflow_wait, &__wait,
                                        TASK_UNINTERRUPTIBLE);
                        spin_unlock_irq(&bitmap->lock);
-                       bitmap->mddev->queue
-                               ->unplug_fn(bitmap->mddev->queue);
+                       blk_unplug(bitmap->mddev->queue);
                        schedule();
                        finish_wait(&bitmap->overflow_wait, &__wait);
                        continue;
@@ -1216,7 +1277,7 @@ int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sect
                case 0:
                        bitmap_file_set_bit(bitmap, offset);
                        bitmap_count_page(bitmap,offset, 1);
-                       blk_plug_device(bitmap->mddev->queue);
+                       blk_plug_device_unlocked(bitmap->mddev->queue);
                        /* fall through */
                case 1:
                        *bmc = 2;
@@ -1231,6 +1292,7 @@ int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sect
                        sectors -= blocks;
                else sectors = 0;
        }
+       bitmap->allclean = 0;
        return 0;
 }
 
@@ -1256,6 +1318,12 @@ void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long secto
                        return;
                }
 
+               if (success &&
+                   bitmap->events_cleared < bitmap->mddev->events) {
+                       bitmap->events_cleared = bitmap->mddev->events;
+                       bitmap->need_sync = 1;
+               }
+
                if (!success && ! (*bmc & NEEDED_MASK))
                        *bmc |= NEEDED_MASK;
 
@@ -1301,6 +1369,7 @@ int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
                }
        }
        spin_unlock_irq(&bitmap->lock);
+       bitmap->allclean = 0;
        return rv;
 }
 
@@ -1337,6 +1406,7 @@ void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int ab
        }
  unlock:
        spin_unlock_irqrestore(&bitmap->lock, flags);
+       bitmap->allclean = 0;
 }
 
 void bitmap_close_sync(struct bitmap *bitmap)
@@ -1347,14 +1417,38 @@ void bitmap_close_sync(struct bitmap *bitmap)
         */
        sector_t sector = 0;
        int blocks;
-       if (!bitmap) return;
+       if (!bitmap)
+               return;
        while (sector < bitmap->mddev->resync_max_sectors) {
                bitmap_end_sync(bitmap, sector, &blocks, 0);
-/*
-               if (sector < 500) printk("bitmap_close_sync: sec %llu blks %d\n",
-                                        (unsigned long long)sector, blocks);
-*/             sector += blocks;
+               sector += blocks;
+       }
+}
+
+void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector)
+{
+       sector_t s = 0;
+       int blocks;
+
+       if (!bitmap)
+               return;
+       if (sector == 0) {
+               bitmap->last_end_sync = jiffies;
+               return;
+       }
+       if (time_before(jiffies, (bitmap->last_end_sync
+                                 + bitmap->daemon_sleep * HZ)))
+               return;
+       wait_event(bitmap->mddev->recovery_wait,
+                  atomic_read(&bitmap->mddev->recovery_active) == 0);
+
+       sector &= ~((1ULL << CHUNK_BLOCK_SHIFT(bitmap)) - 1);
+       s = 0;
+       while (s < sector && s < bitmap->mddev->resync_max_sectors) {
+               bitmap_end_sync(bitmap, s, &blocks, 0);
+               s += blocks;
        }
+       bitmap->last_end_sync = jiffies;
 }
 
 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
@@ -1380,7 +1474,7 @@ static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int n
                set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
        }
        spin_unlock_irq(&bitmap->lock);
-
+       bitmap->allclean = 0;
 }
 
 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
@@ -1548,7 +1642,9 @@ int bitmap_create(mddev_t *mddev)
 
        mddev->thread->timeout = bitmap->daemon_sleep * HZ;
 
-       return bitmap_update_sb(bitmap);
+       bitmap_update_sb(bitmap);
+
+       return (bitmap->flags & BITMAP_WRITE_ERROR) ? -EIO : 0;
 
  error:
        bitmap_free(bitmap);
@@ -1562,3 +1658,4 @@ EXPORT_SYMBOL(bitmap_start_sync);
 EXPORT_SYMBOL(bitmap_end_sync);
 EXPORT_SYMBOL(bitmap_unplug);
 EXPORT_SYMBOL(bitmap_close_sync);
+EXPORT_SYMBOL(bitmap_cond_end_sync);