md/bitmap: prevent bitmap_daemon_work running while initialising bitmap
[linux-flexiantxendom0.git] / drivers / md / bitmap.c
index ab7c8e4..62a8e68 100644 (file)
@@ -13,9 +13,9 @@
  * Still to do:
  *
  * flush after percent set rather than just time based. (maybe both).
- * wait if count gets too high, wake when it drops to half.
  */
 
+#include <linux/blkdev.h>
 #include <linux/module.h>
 #include <linux/errno.h>
 #include <linux/slab.h>
 #include <linux/file.h>
 #include <linux/mount.h>
 #include <linux/buffer_head.h>
-#include <linux/raid/md.h>
-#include <linux/raid/bitmap.h>
-
-/* debug macros */
-
-#define DEBUG 0
-
-#if DEBUG
-/* these are for debugging purposes only! */
-
-/* define one and only one of these */
-#define INJECT_FAULTS_1 0 /* cause bitmap_alloc_page to fail always */
-#define INJECT_FAULTS_2 0 /* cause bitmap file to be kicked when first bit set*/
-#define INJECT_FAULTS_3 0 /* treat bitmap file as kicked at init time */
-#define INJECT_FAULTS_4 0 /* undef */
-#define INJECT_FAULTS_5 0 /* undef */
-#define INJECT_FAULTS_6 0
-
-/* if these are defined, the driver will fail! debug only */
-#define INJECT_FATAL_FAULT_1 0 /* fail kmalloc, causing bitmap_create to fail */
-#define INJECT_FATAL_FAULT_2 0 /* undef */
-#define INJECT_FATAL_FAULT_3 0 /* undef */
-#endif
-
-//#define DPRINTK PRINTK /* set this NULL to avoid verbose debug output */
-#define DPRINTK(x...) do { } while(0)
-
-#ifndef PRINTK
-#  if DEBUG > 0
-#    define PRINTK(x...) printk(KERN_DEBUG x)
-#  else
-#    define PRINTK(x...)
-#  endif
-#endif
-
-static inline char * bmname(struct bitmap *bitmap)
+#include "md.h"
+#include "bitmap.h"
+
+static inline char *bmname(struct bitmap *bitmap)
 {
        return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
 }
 
-
 /*
  * just a placeholder - calls kmalloc for bitmap pages
  */
@@ -74,16 +41,12 @@ static unsigned char *bitmap_alloc_page(struct bitmap *bitmap)
 {
        unsigned char *page;
 
-#ifdef INJECT_FAULTS_1
-       page = NULL;
-#else
-       page = kmalloc(PAGE_SIZE, GFP_NOIO);
-#endif
+       page = kzalloc(PAGE_SIZE, GFP_NOIO);
        if (!page)
                printk("%s: bitmap_alloc_page FAILED\n", bmname(bitmap));
        else
-               PRINTK("%s: bitmap_alloc_page: allocated page at %p\n",
-                       bmname(bitmap), page);
+               pr_debug("%s: bitmap_alloc_page: allocated page at %p\n",
+                        bmname(bitmap), page);
        return page;
 }
 
@@ -92,7 +55,7 @@ static unsigned char *bitmap_alloc_page(struct bitmap *bitmap)
  */
 static void bitmap_free_page(struct bitmap *bitmap, unsigned char *page)
 {
-       PRINTK("%s: bitmap_free_page: free page %p\n", bmname(bitmap), page);
+       pr_debug("%s: bitmap_free_page: free page %p\n", bmname(bitmap), page);
        kfree(page);
 }
 
@@ -106,18 +69,21 @@ static void bitmap_free_page(struct bitmap *bitmap, unsigned char *page)
  * if we find our page, we increment the page's refcount so that it stays
  * allocated while we're using it
  */
-static int bitmap_checkpage(struct bitmap *bitmap, unsigned long page, int create)
+static int bitmap_checkpage(struct bitmap *bitmap,
+                           unsigned long page, int create)
+__releases(bitmap->lock)
+__acquires(bitmap->lock)
 {
        unsigned char *mappage;
 
        if (page >= bitmap->pages) {
-               printk(KERN_ALERT
-                       "%s: invalid bitmap page request: %lu (> %lu)\n",
-                       bmname(bitmap), page, bitmap->pages-1);
+               /* This can happen if bitmap_start_sync goes beyond
+                * End-of-device while looking for a whole page.
+                * It is harmless.
+                */
                return -EINVAL;
        }
 
-
        if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
                return 0;
 
@@ -127,43 +93,34 @@ static int bitmap_checkpage(struct bitmap *bitmap, unsigned long page, int creat
        if (!create)
                return -ENOENT;
 
-       spin_unlock_irq(&bitmap->lock);
-
        /* this page has not been allocated yet */
 
-       if ((mappage = bitmap_alloc_page(bitmap)) == NULL) {
-               PRINTK("%s: bitmap map page allocation failed, hijacking\n",
-                       bmname(bitmap));
+       spin_unlock_irq(&bitmap->lock);
+       mappage = bitmap_alloc_page(bitmap);
+       spin_lock_irq(&bitmap->lock);
+
+       if (mappage == NULL) {
+               pr_debug("%s: bitmap map page allocation failed, hijacking\n",
+                        bmname(bitmap));
                /* failed - set the hijacked flag so that we can use the
                 * pointer as a counter */
-               spin_lock_irq(&bitmap->lock);
                if (!bitmap->bp[page].map)
                        bitmap->bp[page].hijacked = 1;
-               goto out;
-       }
-
-       /* got a page */
-
-       spin_lock_irq(&bitmap->lock);
-
-       /* recheck the page */
-
-       if (bitmap->bp[page].map || bitmap->bp[page].hijacked) {
+       } else if (bitmap->bp[page].map ||
+                  bitmap->bp[page].hijacked) {
                /* somebody beat us to getting the page */
                bitmap_free_page(bitmap, mappage);
                return 0;
-       }
+       } else {
 
-       /* no page was in place and we have one, so install it */
+               /* no page was in place and we have one, so install it */
 
-       memset(mappage, 0, PAGE_SIZE);
-       bitmap->bp[page].map = mappage;
-       bitmap->missing_pages--;
-out:
+               bitmap->bp[page].map = mappage;
+               bitmap->missing_pages--;
+       }
        return 0;
 }
 
-
 /* if page is completely empty, put it back on the free list, or dealloc it */
 /* if page was hijacked, unmark the flag so it might get alloced next time */
 /* Note: lock should be held when calling this */
@@ -179,26 +136,15 @@ static void bitmap_checkfree(struct bitmap *bitmap, unsigned long page)
        if (bitmap->bp[page].hijacked) { /* page was hijacked, undo this now */
                bitmap->bp[page].hijacked = 0;
                bitmap->bp[page].map = NULL;
-               return;
+       } else {
+               /* normal case, free the page */
+               ptr = bitmap->bp[page].map;
+               bitmap->bp[page].map = NULL;
+               bitmap->missing_pages++;
+               bitmap_free_page(bitmap, ptr);
        }
-
-       /* normal case, free the page */
-
-#if 0
-/* actually ... let's not.  We will probably need the page again exactly when
- * memory is tight and we are flusing to disk
- */
-       return;
-#else
-       ptr = bitmap->bp[page].map;
-       bitmap->bp[page].map = NULL;
-       bitmap->missing_pages++;
-       bitmap_free_page(bitmap, ptr);
-       return;
-#endif
 }
 
-
 /*
  * bitmap file handling - read and write the bitmap file and its superblock
  */
@@ -208,42 +154,46 @@ static void bitmap_checkfree(struct bitmap *bitmap, unsigned long page)
  */
 
 /* IO operations when bitmap is stored near all superblocks */
-static struct page *read_sb_page(mddev_t *mddev, long offset,
+static struct page *read_sb_page(struct mddev *mddev, loff_t 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 md_rdev *rdev;
        sector_t target;
+       int did_alloc = 0;
 
-       if (!page)
+       if (!page) {
                page = alloc_page(GFP_KERNEL);
-       if (!page)
-               return ERR_PTR(-ENOMEM);
+               if (!page)
+                       return ERR_PTR(-ENOMEM);
+               did_alloc = 1;
+       }
 
-       rdev_for_each(rdev, tmp, mddev) {
+       list_for_each_entry(rdev, &mddev->disks, same_set) {
                if (! test_bit(In_sync, &rdev->flags)
                    || test_bit(Faulty, &rdev->flags))
                        continue;
 
-               target = rdev->sb_start + offset + index * (PAGE_SIZE/512);
+               target = offset + index * (PAGE_SIZE/512);
 
-               if (sync_page_io(rdev->bdev, target,
-                                roundup(size, bdev_hardsect_size(rdev->bdev)),
-                                page, READ)) {
+               if (sync_page_io(rdev, target,
+                                roundup(size, bdev_logical_block_size(rdev->bdev)),
+                                page, READ, true)) {
                        page->index = index;
                        attach_page_buffers(page, NULL); /* so that free_buffer will
                                                          * quietly no-op */
                        return page;
                }
        }
+       if (did_alloc)
+               put_page(page);
        return ERR_PTR(-EIO);
 
 }
 
-static mdk_rdev_t *next_active_rdev(mdk_rdev_t *rdev, mddev_t *mddev)
+static struct md_rdev *next_active_rdev(struct md_rdev *rdev, struct mddev *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
@@ -264,9 +214,8 @@ static mdk_rdev_t *next_active_rdev(mdk_rdev_t *rdev, mddev_t *mddev)
                pos = &rdev->same_set;
        }
        list_for_each_continue_rcu(pos, &mddev->disks) {
-               rdev = list_entry(pos, mdk_rdev_t, same_set);
+               rdev = list_entry(pos, struct md_rdev, 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);
@@ -280,44 +229,59 @@ static mdk_rdev_t *next_active_rdev(mdk_rdev_t *rdev, mddev_t *mddev)
 
 static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
 {
-       mdk_rdev_t *rdev = NULL;
-       mddev_t *mddev = bitmap->mddev;
+       struct md_rdev *rdev = NULL;
+       struct block_device *bdev;
+       struct mddev *mddev = bitmap->mddev;
 
        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,
-                                              bdev_hardsect_size(rdev->bdev));
-                       /* Just make sure we aren't corrupting data or
-                        * metadata
-                        */
-                       if (bitmap->offset < 0) {
-                               /* DATA  BITMAP METADATA  */
-                               if (bitmap->offset
-                                   + (long)(page->index * (PAGE_SIZE/512))
-                                   + size/512 > 0)
-                                       /* bitmap runs in to metadata */
-                                       goto bad_alignment;
-                               if (rdev->data_offset + mddev->size*2
-                                   > rdev->sb_start + bitmap->offset)
-                                       /* data runs in to bitmap */
-                                       goto bad_alignment;
-                       } else if (rdev->sb_start < rdev->data_offset) {
-                               /* METADATA BITMAP DATA */
-                               if (rdev->sb_start
-                                   + bitmap->offset
-                                   + page->index*(PAGE_SIZE/512) + size/512
-                                   > rdev->data_offset)
-                                       /* bitmap runs in to data */
-                                       goto bad_alignment;
-                       } else {
-                               /* DATA METADATA BITMAP - no problems */
-                       }
-                       md_super_write(mddev, rdev,
-                                      rdev->sb_start + bitmap->offset
-                                      + page->index * (PAGE_SIZE/512),
-                                      size,
-                                      page);
+               int size = PAGE_SIZE;
+               loff_t offset = mddev->bitmap_info.offset;
+
+               bdev = (rdev->meta_bdev) ? rdev->meta_bdev : rdev->bdev;
+
+               if (page->index == bitmap->file_pages-1)
+                       size = roundup(bitmap->last_page_size,
+                                      bdev_logical_block_size(bdev));
+               /* Just make sure we aren't corrupting data or
+                * metadata
+                */
+               if (mddev->external) {
+                       /* Bitmap could be anywhere. */
+                       if (rdev->sb_start + offset + (page->index
+                                                      * (PAGE_SIZE/512))
+                           > rdev->data_offset
+                           &&
+                           rdev->sb_start + offset
+                           < (rdev->data_offset + mddev->dev_sectors
+                            + (PAGE_SIZE/512)))
+                               goto bad_alignment;
+               } else if (offset < 0) {
+                       /* DATA  BITMAP METADATA  */
+                       if (offset
+                           + (long)(page->index * (PAGE_SIZE/512))
+                           + size/512 > 0)
+                               /* bitmap runs in to metadata */
+                               goto bad_alignment;
+                       if (rdev->data_offset + mddev->dev_sectors
+                           > rdev->sb_start + offset)
+                               /* data runs in to bitmap */
+                               goto bad_alignment;
+               } else if (rdev->sb_start < rdev->data_offset) {
+                       /* METADATA BITMAP DATA */
+                       if (rdev->sb_start
+                           + offset
+                           + page->index*(PAGE_SIZE/512) + size/512
+                           > rdev->data_offset)
+                               /* bitmap runs in to data */
+                               goto bad_alignment;
+               } else {
+                       /* DATA METADATA BITMAP - no problems */
+               }
+               md_super_write(mddev, rdev,
+                              rdev->sb_start + offset
+                              + page->index * (PAGE_SIZE/512),
+                              size,
+                              page);
        }
 
        if (wait)
@@ -325,7 +289,6 @@ static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
        return 0;
 
  bad_alignment:
-       rcu_read_unlock();
        return -EINVAL;
 }
 
@@ -350,14 +313,13 @@ static void write_page(struct bitmap *bitmap, struct page *page, int wait)
                        atomic_inc(&bitmap->pending_writes);
                        set_buffer_locked(bh);
                        set_buffer_mapped(bh);
-                       submit_bh(WRITE, bh);
+                       submit_bh(WRITE | REQ_SYNC, bh);
                        bh = bh->b_this_page;
                }
 
-               if (wait) {
+               if (wait)
                        wait_event(bitmap->write_wait,
                                   atomic_read(&bitmap->pending_writes)==0);
-               }
        }
        if (bitmap->flags & BITMAP_WRITE_ERROR)
                bitmap_file_kick(bitmap);
@@ -414,8 +376,8 @@ static struct page *read_page(struct file *file, unsigned long index,
        struct buffer_head *bh;
        sector_t block;
 
-       PRINTK("read bitmap file (%dB @ %Lu)\n", (int)PAGE_SIZE,
-                       (unsigned long long)index << PAGE_SHIFT);
+       pr_debug("read bitmap file (%dB @ %llu)\n", (int)PAGE_SIZE,
+                (unsigned long long)index << PAGE_SHIFT);
 
        page = alloc_page(GFP_KERNEL);
        if (!page)
@@ -468,7 +430,7 @@ static struct page *read_page(struct file *file, unsigned long index,
        }
 out:
        if (IS_ERR(page))
-               printk(KERN_ALERT "md: bitmap read error: (%dB @ %Lu): %ld\n",
+               printk(KERN_ALERT "md: bitmap read error: (%dB @ %llu): %ld\n",
                        (int)PAGE_SIZE,
                        (unsigned long long)index << PAGE_SHIFT,
                        PTR_ERR(page));
@@ -487,19 +449,24 @@ void bitmap_update_sb(struct bitmap *bitmap)
 
        if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
                return;
+       if (bitmap->mddev->bitmap_info.external)
+               return;
        spin_lock_irqsave(&bitmap->lock, flags);
        if (!bitmap->sb_page) { /* no superblock */
                spin_unlock_irqrestore(&bitmap->lock, flags);
                return;
        }
        spin_unlock_irqrestore(&bitmap->lock, flags);
-       sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
+       sb = kmap_atomic(bitmap->sb_page, KM_USER0);
        sb->events = cpu_to_le64(bitmap->mddev->events);
-       if (bitmap->mddev->events < bitmap->events_cleared) {
+       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);
-       }
+       sb->events_cleared = cpu_to_le64(bitmap->events_cleared);
+       sb->state = cpu_to_le32(bitmap->flags);
+       /* Just in case these have been changed via sysfs: */
+       sb->daemon_sleep = cpu_to_le32(bitmap->mddev->bitmap_info.daemon_sleep/HZ);
+       sb->write_behind = cpu_to_le32(bitmap->mddev->bitmap_info.max_write_behind);
        kunmap_atomic(sb, KM_USER0);
        write_page(bitmap, bitmap->sb_page, 1);
 }
@@ -511,7 +478,7 @@ void bitmap_print_sb(struct bitmap *bitmap)
 
        if (!bitmap || !bitmap->sb_page)
                return;
-       sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
+       sb = kmap_atomic(bitmap->sb_page, KM_USER0);
        printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
        printk(KERN_DEBUG "         magic: %08x\n", le32_to_cpu(sb->magic));
        printk(KERN_DEBUG "       version: %d\n", le32_to_cpu(sb->version));
@@ -533,6 +500,82 @@ void bitmap_print_sb(struct bitmap *bitmap)
        kunmap_atomic(sb, KM_USER0);
 }
 
+/*
+ * bitmap_new_disk_sb
+ * @bitmap
+ *
+ * This function is somewhat the reverse of bitmap_read_sb.  bitmap_read_sb
+ * reads and verifies the on-disk bitmap superblock and populates bitmap_info.
+ * This function verifies 'bitmap_info' and populates the on-disk bitmap
+ * structure, which is to be written to disk.
+ *
+ * Returns: 0 on success, -Exxx on error
+ */
+static int bitmap_new_disk_sb(struct bitmap *bitmap)
+{
+       bitmap_super_t *sb;
+       unsigned long chunksize, daemon_sleep, write_behind;
+       int err = -EINVAL;
+
+       bitmap->sb_page = alloc_page(GFP_KERNEL);
+       if (IS_ERR(bitmap->sb_page)) {
+               err = PTR_ERR(bitmap->sb_page);
+               bitmap->sb_page = NULL;
+               return err;
+       }
+       bitmap->sb_page->index = 0;
+
+       sb = kmap_atomic(bitmap->sb_page, KM_USER0);
+
+       sb->magic = cpu_to_le32(BITMAP_MAGIC);
+       sb->version = cpu_to_le32(BITMAP_MAJOR_HI);
+
+       chunksize = bitmap->mddev->bitmap_info.chunksize;
+       BUG_ON(!chunksize);
+       if (!is_power_of_2(chunksize)) {
+               kunmap_atomic(sb, KM_USER0);
+               printk(KERN_ERR "bitmap chunksize not a power of 2\n");
+               return -EINVAL;
+       }
+       sb->chunksize = cpu_to_le32(chunksize);
+
+       daemon_sleep = bitmap->mddev->bitmap_info.daemon_sleep;
+       if (!daemon_sleep ||
+           (daemon_sleep < 1) || (daemon_sleep > MAX_SCHEDULE_TIMEOUT)) {
+               printk(KERN_INFO "Choosing daemon_sleep default (5 sec)\n");
+               daemon_sleep = 5 * HZ;
+       }
+       sb->daemon_sleep = cpu_to_le32(daemon_sleep);
+       bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
+
+       /*
+        * FIXME: write_behind for RAID1.  If not specified, what
+        * is a good choice?  We choose COUNTER_MAX / 2 arbitrarily.
+        */
+       write_behind = bitmap->mddev->bitmap_info.max_write_behind;
+       if (write_behind > COUNTER_MAX)
+               write_behind = COUNTER_MAX / 2;
+       sb->write_behind = cpu_to_le32(write_behind);
+       bitmap->mddev->bitmap_info.max_write_behind = write_behind;
+
+       /* keep the array size field of the bitmap superblock up to date */
+       sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
+
+       memcpy(sb->uuid, bitmap->mddev->uuid, 16);
+
+       bitmap->flags |= BITMAP_STALE;
+       sb->state |= cpu_to_le32(BITMAP_STALE);
+       bitmap->events_cleared = bitmap->mddev->events;
+       sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
+
+       bitmap->flags |= BITMAP_HOSTENDIAN;
+       sb->version = cpu_to_le32(BITMAP_MAJOR_HOSTENDIAN);
+
+       kunmap_atomic(sb, KM_USER0);
+
+       return 0;
+}
+
 /* read the superblock from the bitmap file and initialize some bitmap fields */
 static int bitmap_read_sb(struct bitmap *bitmap)
 {
@@ -549,7 +592,8 @@ 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,
+               bitmap->sb_page = read_sb_page(bitmap->mddev,
+                                              bitmap->mddev->bitmap_info.offset,
                                               NULL,
                                               0, sizeof(bitmap_super_t));
        }
@@ -559,10 +603,10 @@ static int bitmap_read_sb(struct bitmap *bitmap)
                return err;
        }
 
-       sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
+       sb = kmap_atomic(bitmap->sb_page, KM_USER0);
 
        chunksize = le32_to_cpu(sb->chunksize);
-       daemon_sleep = le32_to_cpu(sb->daemon_sleep);
+       daemon_sleep = le32_to_cpu(sb->daemon_sleep) * HZ;
        write_behind = le32_to_cpu(sb->write_behind);
 
        /* verify that the bitmap-specific fields are valid */
@@ -571,11 +615,11 @@ static int bitmap_read_sb(struct bitmap *bitmap)
        else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
                 le32_to_cpu(sb->version) > BITMAP_MAJOR_HI)
                reason = "unrecognized superblock version";
-       else if (chunksize < PAGE_SIZE)
+       else if (chunksize < 512)
                reason = "bitmap chunksize too small";
-       else if ((1 << ffz(~chunksize)) != chunksize)
+       else if (!is_power_of_2(chunksize))
                reason = "bitmap chunksize not a power of 2";
-       else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT / HZ)
+       else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT)
                reason = "daemon sleep period out of range";
        else if (write_behind > COUNTER_MAX)
                reason = "write-behind limit out of range (0 - 16383)";
@@ -609,15 +653,14 @@ static int bitmap_read_sb(struct bitmap *bitmap)
        }
 success:
        /* assign fields using values from superblock */
-       bitmap->chunksize = chunksize;
-       bitmap->daemon_sleep = daemon_sleep;
-       bitmap->daemon_lastrun = jiffies;
-       bitmap->max_write_behind = write_behind;
+       bitmap->mddev->bitmap_info.chunksize = chunksize;
+       bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
+       bitmap->mddev->bitmap_info.max_write_behind = write_behind;
        bitmap->flags |= le32_to_cpu(sb->state);
        if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
                bitmap->flags |= BITMAP_HOSTENDIAN;
        bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
-       if (sb->state & cpu_to_le32(BITMAP_STALE))
+       if (bitmap->flags & BITMAP_STALE)
                bitmap->events_cleared = bitmap->mddev->events;
        err = 0;
 out:
@@ -646,14 +689,19 @@ static int bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
                return 0;
        }
        spin_unlock_irqrestore(&bitmap->lock, flags);
-       sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
+       sb = 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;
-               case MASK_UNSET: sb->state &= cpu_to_le32(~bits);
-                               break;
-               default: BUG();
+       case MASK_SET:
+               sb->state |= cpu_to_le32(bits);
+               bitmap->flags |= bits;
+               break;
+       case MASK_UNSET:
+               sb->state &= cpu_to_le32(~bits);
+               bitmap->flags &= ~bits;
+               break;
+       default:
+               BUG();
        }
        kunmap_atomic(sb, KM_USER0);
        return old;
@@ -663,16 +711,26 @@ static int bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
  * general bitmap file operations
  */
 
+/*
+ * on-disk bitmap:
+ *
+ * Use one bit per "chunk" (block set). We do the disk I/O on the bitmap
+ * file a page at a time. There's a superblock at the start of the file.
+ */
 /* calculate the index of the page that contains this bit */
-static inline unsigned long file_page_index(unsigned long chunk)
+static inline unsigned long file_page_index(struct bitmap *bitmap, unsigned long chunk)
 {
-       return CHUNK_BIT_OFFSET(chunk) >> PAGE_BIT_SHIFT;
+       if (!bitmap->mddev->bitmap_info.external)
+               chunk += sizeof(bitmap_super_t) << 3;
+       return chunk >> PAGE_BIT_SHIFT;
 }
 
 /* calculate the (bit) offset of this bit within a page */
-static inline unsigned long file_page_offset(unsigned long chunk)
+static inline unsigned long file_page_offset(struct bitmap *bitmap, unsigned long chunk)
 {
-       return CHUNK_BIT_OFFSET(chunk) & (PAGE_BITS - 1);
+       if (!bitmap->mddev->bitmap_info.external)
+               chunk += sizeof(bitmap_super_t) << 3;
+       return chunk & (PAGE_BITS - 1);
 }
 
 /*
@@ -683,13 +741,14 @@ static inline unsigned long file_page_offset(unsigned long chunk)
  * 0 or page 1
  */
 static inline struct page *filemap_get_page(struct bitmap *bitmap,
-                                       unsigned long chunk)
+                                           unsigned long chunk)
 {
-       if (file_page_index(chunk) >= bitmap->file_pages) return NULL;
-       return bitmap->filemap[file_page_index(chunk) - file_page_index(0)];
+       if (file_page_index(bitmap, chunk) >= bitmap->file_pages)
+               return NULL;
+       return bitmap->filemap[file_page_index(bitmap, chunk)
+                              - file_page_index(bitmap, 0)];
 }
 
-
 static void bitmap_file_unmap(struct bitmap *bitmap)
 {
        struct page **map, *sb_page;
@@ -709,7 +768,7 @@ static void bitmap_file_unmap(struct bitmap *bitmap)
        spin_unlock_irqrestore(&bitmap->lock, flags);
 
        while (pages--)
-               if (map[pages]->index != 0) /* 0 is sb_page, release it below */
+               if (map[pages] != sb_page) /* 0 is sb_page, release it below */
                        free_buffers(map[pages]);
        kfree(map);
        kfree(attr);
@@ -740,7 +799,6 @@ static void bitmap_file_put(struct bitmap *bitmap)
        }
 }
 
-
 /*
  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
  * then it is no longer reliable, so we stop using it and we mark the file
@@ -759,7 +817,6 @@ static void bitmap_file_kick(struct bitmap *bitmap)
                                ptr = d_path(&bitmap->file->f_path, path,
                                             PAGE_SIZE);
 
-
                        printk(KERN_ALERT
                              "%s: kicking failed bitmap file %s from array!\n",
                              bmname(bitmap), IS_ERR(ptr) ? "" : ptr);
@@ -777,9 +834,10 @@ static void bitmap_file_kick(struct bitmap *bitmap)
 }
 
 enum bitmap_page_attr {
-       BITMAP_PAGE_DIRTY = 0, // there are set bits that need to be synced
-       BITMAP_PAGE_CLEAN = 1, // there are bits that might need to be cleared
-       BITMAP_PAGE_NEEDWRITE=2, // there are cleared bits that need to be synced
+       BITMAP_PAGE_DIRTY = 0,     /* there are set bits that need to be synced */
+       BITMAP_PAGE_PENDING = 1,   /* there are bits that are being cleaned.
+                                   * i.e. counter is 1 or 2. */
+       BITMAP_PAGE_NEEDWRITE = 2, /* there are cleared bits that need to be synced */
 };
 
 static inline void set_page_attr(struct bitmap *bitmap, struct page *page,
@@ -814,26 +872,24 @@ static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
        void *kaddr;
        unsigned long chunk = block >> CHUNK_BLOCK_SHIFT(bitmap);
 
-       if (!bitmap->filemap) {
+       if (!bitmap->filemap)
                return;
-       }
 
        page = filemap_get_page(bitmap, chunk);
-       if (!page) return;
-       bit = file_page_offset(chunk);
+       if (!page)
+               return;
+       bit = file_page_offset(bitmap, chunk);
 
-       /* set the bit */
+       /* set the bit */
        kaddr = kmap_atomic(page, KM_USER0);
        if (bitmap->flags & BITMAP_HOSTENDIAN)
                set_bit(bit, kaddr);
        else
-               ext2_set_bit(bit, kaddr);
+               __set_bit_le(bit, kaddr);
        kunmap_atomic(kaddr, KM_USER0);
-       PRINTK("set file bit %lu page %lu\n", bit, page->index);
-
+       pr_debug("set file bit %lu page %lu\n", bit, page->index);
        /* record page number so it gets flushed to disk when unplug occurs */
        set_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
-
 }
 
 /* this gets called when the md device is ready to unplug its underlying
@@ -866,7 +922,7 @@ void bitmap_unplug(struct bitmap *bitmap)
                        wait = 1;
                spin_unlock_irqrestore(&bitmap->lock, flags);
 
-               if (dirty | need_write)
+               if (dirty || need_write)
                        write_page(bitmap, page, 0);
        }
        if (wait) { /* if any writes were performed, we need to wait on them */
@@ -879,6 +935,7 @@ void bitmap_unplug(struct bitmap *bitmap)
        if (bitmap->flags & BITMAP_WRITE_ERROR)
                bitmap_file_kick(bitmap);
 }
+EXPORT_SYMBOL(bitmap_unplug);
 
 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
@@ -906,26 +963,24 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
        chunks = bitmap->chunks;
        file = bitmap->file;
 
-       BUG_ON(!file && !bitmap->offset);
+       BUG_ON(!file && !bitmap->mddev->bitmap_info.offset);
 
-#ifdef INJECT_FAULTS_3
-       outofdate = 1;
-#else
        outofdate = bitmap->flags & BITMAP_STALE;
-#endif
        if (outofdate)
                printk(KERN_INFO "%s: bitmap file is out of date, doing full "
                        "recovery\n", bmname(bitmap));
 
-       bytes = (chunks + 7) / 8;
+       bytes = DIV_ROUND_UP(bitmap->chunks, 8);
+       if (!bitmap->mddev->bitmap_info.external)
+               bytes += sizeof(bitmap_super_t);
 
-       num_pages = (bytes + sizeof(bitmap_super_t) + PAGE_SIZE - 1) / PAGE_SIZE;
+       num_pages = DIV_ROUND_UP(bytes, PAGE_SIZE);
 
-       if (file && i_size_read(file->f_mapping->host) < bytes + sizeof(bitmap_super_t)) {
+       if (file && i_size_read(file->f_mapping->host) < bytes) {
                printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
                        bmname(bitmap),
                        (unsigned long) i_size_read(file->f_mapping->host),
-                       bytes + sizeof(bitmap_super_t));
+                       bytes);
                goto err;
        }
 
@@ -937,7 +992,7 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
 
        /* 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)),
+               roundup(DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
                GFP_KERNEL);
        if (!bitmap->filemap_attr)
                goto err;
@@ -946,17 +1001,16 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
 
        for (i = 0; i < chunks; i++) {
                int b;
-               index = file_page_index(i);
-               bit = file_page_offset(i);
+               index = file_page_index(bitmap, i);
+               bit = file_page_offset(bitmap, i);
                if (index != oldindex) { /* this is a new page, read it in */
                        int count;
                        /* unmap the old page, we're done with it */
                        if (index == num_pages-1)
-                               count = bytes + sizeof(bitmap_super_t)
-                                       - index * PAGE_SIZE;
+                               count = bytes - index * PAGE_SIZE;
                        else
                                count = PAGE_SIZE;
-                       if (index == 0) {
+                       if (index == 0 && bitmap->sb_page) {
                                /*
                                 * if we're here then the superblock page
                                 * contains some bits (PAGE_SIZE != sizeof sb)
@@ -964,14 +1018,18 @@ 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);
+                               if (!file)
+                                       page = read_sb_page(
+                                               bitmap->mddev,
+                                               bitmap->mddev->bitmap_info.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,
+                               page = read_sb_page(bitmap->mddev,
+                                                   bitmap->mddev->bitmap_info.offset,
                                                    NULL,
                                                    index, count);
                                offset = 0;
@@ -984,10 +1042,13 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
                        oldindex = index;
                        oldpage = page;
 
+                       bitmap->filemap[bitmap->file_pages++] = page;
+                       bitmap->last_page_size = count;
+
                        if (outofdate) {
                                /*
                                 * if bitmap is out of date, dirty the
-                                * whole page and write it out
+                                * whole page and write it out
                                 */
                                paddr = kmap_atomic(page, KM_USER0);
                                memset(paddr + offset, 0xff,
@@ -996,33 +1057,28 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
                                write_page(bitmap, page, 1);
 
                                ret = -EIO;
-                               if (bitmap->flags & BITMAP_WRITE_ERROR) {
-                                       /* release, page not in filemap yet */
-                                       put_page(page);
+                               if (bitmap->flags & BITMAP_WRITE_ERROR)
                                        goto err;
-                               }
                        }
-
-                       bitmap->filemap[bitmap->file_pages++] = page;
-                       bitmap->last_page_size = count;
                }
                paddr = kmap_atomic(page, KM_USER0);
                if (bitmap->flags & BITMAP_HOSTENDIAN)
                        b = test_bit(bit, paddr);
                else
-                       b = ext2_test_bit(bit, paddr);
+                       b = test_bit_le(bit, paddr);
                kunmap_atomic(paddr, KM_USER0);
                if (b) {
                        /* if the disk bit is set, set the memory bit */
-                       bitmap_set_memory_bits(bitmap, i << CHUNK_BLOCK_SHIFT(bitmap),
-                                              ((i+1) << (CHUNK_BLOCK_SHIFT(bitmap)) >= start)
-                               );
+                       int needed = ((sector_t)(i+1) << (CHUNK_BLOCK_SHIFT(bitmap))
+                                     >= start);
+                       bitmap_set_memory_bits(bitmap,
+                                              (sector_t)i << CHUNK_BLOCK_SHIFT(bitmap),
+                                              needed);
                        bit_cnt++;
-                       set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
                }
        }
 
-       /* everything went OK */
+       /* everything went OK */
        ret = 0;
        bitmap_mask_state(bitmap, BITMAP_STALE, MASK_UNSET);
 
@@ -1032,8 +1088,8 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
        }
 
        printk(KERN_INFO "%s: bitmap initialized from disk: "
-               "read %lu/%lu pages, set %lu bits\n",
-               bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt);
+              "read %lu/%lu pages, set %lu of %lu bits\n",
+              bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt, chunks);
 
        return 0;
 
@@ -1050,25 +1106,23 @@ void bitmap_write_all(struct bitmap *bitmap)
         */
        int i;
 
-       for (i=0; i < bitmap->file_pages; i++)
+       spin_lock_irq(&bitmap->lock);
+       for (i = 0; i < bitmap->file_pages; i++)
                set_page_attr(bitmap, bitmap->filemap[i],
                              BITMAP_PAGE_NEEDWRITE);
+       bitmap->allclean = 0;
+       spin_unlock_irq(&bitmap->lock);
 }
 
-
 static void bitmap_count_page(struct bitmap *bitmap, sector_t offset, int inc)
 {
        sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
        unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
        bitmap->bp[page].count += inc;
-/*
-       if (page == 0) printk("count page 0, offset %llu: %d gives %d\n",
-                             (unsigned long long)offset, inc, bitmap->bp[page].count);
-*/
        bitmap_checkfree(bitmap, page);
 }
 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
-                                           sector_t offset, int *blocks,
+                                           sector_t offset, sector_t *blocks,
                                            int create);
 
 /*
@@ -1076,61 +1130,72 @@ static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
  *                     out to disk
  */
 
-void bitmap_daemon_work(struct bitmap *bitmap)
+void bitmap_daemon_work(struct mddev *mddev)
 {
+       struct bitmap *bitmap;
        unsigned long j;
        unsigned long flags;
        struct page *page = NULL, *lastpage = NULL;
-       int blocks;
+       sector_t blocks;
        void *paddr;
 
-       if (bitmap == NULL)
+       /* Use a mutex to guard daemon_work against
+        * bitmap_destroy.
+        */
+       mutex_lock(&mddev->bitmap_info.mutex);
+       bitmap = mddev->bitmap;
+       if (bitmap == NULL) {
+               mutex_unlock(&mddev->bitmap_info.mutex);
                return;
-       if (time_before(jiffies, bitmap->daemon_lastrun + bitmap->daemon_sleep*HZ))
+       }
+       if (time_before(jiffies, bitmap->daemon_lastrun
+                       + bitmap->mddev->bitmap_info.daemon_sleep))
                goto done;
 
        bitmap->daemon_lastrun = jiffies;
        if (bitmap->allclean) {
                bitmap->mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
-               return;
+               goto done;
        }
        bitmap->allclean = 1;
 
+       spin_lock_irqsave(&bitmap->lock, flags);
        for (j = 0; j < bitmap->chunks; j++) {
                bitmap_counter_t *bmc;
-               spin_lock_irqsave(&bitmap->lock, flags);
-               if (!bitmap->filemap) {
+               if (!bitmap->filemap)
                        /* error or shutdown */
-                       spin_unlock_irqrestore(&bitmap->lock, flags);
                        break;
-               }
 
                page = filemap_get_page(bitmap, j);
 
                if (page != lastpage) {
                        /* skip this page unless it's marked as needing cleaning */
-                       if (!test_page_attr(bitmap, page, BITMAP_PAGE_CLEAN)) {
+                       if (!test_page_attr(bitmap, page, BITMAP_PAGE_PENDING)) {
                                int need_write = test_page_attr(bitmap, page,
                                                                BITMAP_PAGE_NEEDWRITE);
                                if (need_write)
                                        clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 
                                spin_unlock_irqrestore(&bitmap->lock, flags);
-                               if (need_write) {
+                               if (need_write)
                                        write_page(bitmap, page, 0);
-                                       bitmap->allclean = 0;
-                               }
+                               spin_lock_irqsave(&bitmap->lock, flags);
+                               j |= (PAGE_BITS - 1);
                                continue;
                        }
 
                        /* grab the new page, sync and release the old */
                        if (lastpage != NULL) {
-                               if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
-                                       clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
+                               if (test_page_attr(bitmap, lastpage,
+                                                  BITMAP_PAGE_NEEDWRITE)) {
+                                       clear_page_attr(bitmap, lastpage,
+                                                       BITMAP_PAGE_NEEDWRITE);
                                        spin_unlock_irqrestore(&bitmap->lock, flags);
                                        write_page(bitmap, lastpage, 0);
                                } else {
-                                       set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
+                                       set_page_attr(bitmap, lastpage,
+                                                     BITMAP_PAGE_NEEDWRITE);
+                                       bitmap->allclean = 0;
                                        spin_unlock_irqrestore(&bitmap->lock, flags);
                                }
                        } else
@@ -1140,7 +1205,8 @@ void bitmap_daemon_work(struct bitmap *bitmap)
                        /* We are possibly going to clear some bits, so make
                         * sure that events_cleared is up-to-date.
                         */
-                       if (bitmap->need_sync) {
+                       if (bitmap->need_sync &&
+                           bitmap->mddev->bitmap_info.external == 0) {
                                bitmap_super_t *sb;
                                bitmap->need_sync = 0;
                                sb = kmap_atomic(bitmap->sb_page, KM_USER0);
@@ -1150,37 +1216,43 @@ void bitmap_daemon_work(struct bitmap *bitmap)
                                write_page(bitmap, bitmap->sb_page, 1);
                        }
                        spin_lock_irqsave(&bitmap->lock, flags);
-                       clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
-               }
-               bmc = bitmap_get_counter(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
-                                       &blocks, 0);
-               if (bmc) {
-/*
-  if (j < 100) printk("bitmap: j=%lu, *bmc = 0x%x\n", j, *bmc);
-*/
-                       if (*bmc)
+                       if (!bitmap->need_sync)
+                               clear_page_attr(bitmap, page, BITMAP_PAGE_PENDING);
+                       else
                                bitmap->allclean = 0;
-
-                       if (*bmc == 2) {
-                               *bmc=1; /* maybe clear the bit next time */
-                               set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
-                       } else if (*bmc == 1) {
+               }
+               bmc = bitmap_get_counter(bitmap,
+                                        (sector_t)j << CHUNK_BLOCK_SHIFT(bitmap),
+                                        &blocks, 0);
+               if (!bmc)
+                       j |= PAGE_COUNTER_MASK;
+               else if (*bmc) {
+                       if (*bmc == 1 && !bitmap->need_sync) {
                                /* we can clear the bit */
                                *bmc = 0;
-                               bitmap_count_page(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
+                               bitmap_count_page(bitmap,
+                                                 (sector_t)j << CHUNK_BLOCK_SHIFT(bitmap),
                                                  -1);
 
                                /* clear the bit */
                                paddr = kmap_atomic(page, KM_USER0);
                                if (bitmap->flags & BITMAP_HOSTENDIAN)
-                                       clear_bit(file_page_offset(j), paddr);
+                                       clear_bit(file_page_offset(bitmap, j),
+                                                 paddr);
                                else
-                                       ext2_clear_bit(file_page_offset(j), paddr);
+                                       __clear_bit_le(
+                                               file_page_offset(bitmap,
+                                                                j),
+                                               paddr);
                                kunmap_atomic(paddr, KM_USER0);
+                       } else if (*bmc <= 2) {
+                               *bmc = 1; /* maybe clear the bit next time */
+                               set_page_attr(bitmap, page, BITMAP_PAGE_PENDING);
+                               bitmap->allclean = 0;
                        }
                }
-               spin_unlock_irqrestore(&bitmap->lock, flags);
        }
+       spin_unlock_irqrestore(&bitmap->lock, flags);
 
        /* now sync the final page */
        if (lastpage != NULL) {
@@ -1191,18 +1263,23 @@ void bitmap_daemon_work(struct bitmap *bitmap)
                        write_page(bitmap, lastpage, 0);
                } else {
                        set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
+                       bitmap->allclean = 0;
                        spin_unlock_irqrestore(&bitmap->lock, flags);
                }
        }
 
  done:
        if (bitmap->allclean == 0)
-               bitmap->mddev->thread->timeout = bitmap->daemon_sleep * HZ;
+               bitmap->mddev->thread->timeout =
+                       bitmap->mddev->bitmap_info.daemon_sleep;
+       mutex_unlock(&mddev->bitmap_info.mutex);
 }
 
 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
-                                           sector_t offset, int *blocks,
+                                           sector_t offset, sector_t *blocks,
                                            int create)
+__releases(bitmap->lock)
+__acquires(bitmap->lock)
 {
        /* If 'create', we might release the lock and reclaim it.
         * The lock must have been taken with interrupts enabled.
@@ -1212,43 +1289,52 @@ static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
        unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
        unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
        sector_t csize;
+       int err;
 
-       if (bitmap_checkpage(bitmap, page, create) < 0) {
+       err = bitmap_checkpage(bitmap, page, create);
+
+       if (bitmap->bp[page].hijacked ||
+           bitmap->bp[page].map == NULL)
+               csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap) +
+                                         PAGE_COUNTER_SHIFT - 1);
+       else
                csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
-               *blocks = csize - (offset & (csize- 1));
+       *blocks = csize - (offset & (csize - 1));
+
+       if (err < 0)
                return NULL;
-       }
+
        /* now locked ... */
 
        if (bitmap->bp[page].hijacked) { /* hijacked pointer */
                /* should we use the first or second counter field
                 * of the hijacked pointer? */
                int hi = (pageoff > PAGE_COUNTER_MASK);
-               csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap) +
-                                         PAGE_COUNTER_SHIFT - 1);
-               *blocks = csize - (offset & (csize- 1));
                return  &((bitmap_counter_t *)
                          &bitmap->bp[page].map)[hi];
-       } else { /* page is allocated */
-               csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
-               *blocks = csize - (offset & (csize- 1));
+       } else /* page is allocated */
                return (bitmap_counter_t *)
                        &(bitmap->bp[page].map[pageoff]);
-       }
 }
 
 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
 {
-       if (!bitmap) return 0;
+       if (!bitmap)
+               return 0;
 
        if (behind) {
+               int bw;
                atomic_inc(&bitmap->behind_writes);
-               PRINTK(KERN_DEBUG "inc write-behind count %d/%d\n",
-                 atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
+               bw = atomic_read(&bitmap->behind_writes);
+               if (bw > bitmap->behind_writes_used)
+                       bitmap->behind_writes_used = bw;
+
+               pr_debug("inc write-behind count %d/%lu\n",
+                        bw, bitmap->mddev->bitmap_info.max_write_behind);
        }
 
        while (sectors) {
-               int blocks;
+               sector_t blocks;
                bitmap_counter_t *bmc;
 
                spin_lock_irq(&bitmap->lock);
@@ -1258,7 +1344,7 @@ int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sect
                        return 0;
                }
 
-               if (unlikely((*bmc & COUNTER_MAX) == COUNTER_MAX)) {
+               if (unlikely(COUNTER(*bmc) == COUNTER_MAX)) {
                        DEFINE_WAIT(__wait);
                        /* note that it is safe to do the prepare_to_wait
                         * after the test as long as we do it before dropping
@@ -1267,17 +1353,15 @@ 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);
-                       blk_unplug(bitmap->mddev->queue);
-                       schedule();
+                       io_schedule();
                        finish_wait(&bitmap->overflow_wait, &__wait);
                        continue;
                }
 
-               switch(*bmc) {
+               switch (*bmc) {
                case 0:
                        bitmap_file_set_bit(bitmap, offset);
-                       bitmap_count_page(bitmap,offset, 1);
-                       blk_plug_device_unlocked(bitmap->mddev->queue);
+                       bitmap_count_page(bitmap, offset, 1);
                        /* fall through */
                case 1:
                        *bmc = 2;
@@ -1290,24 +1374,28 @@ int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sect
                offset += blocks;
                if (sectors > blocks)
                        sectors -= blocks;
-               else sectors = 0;
+               else
+                       sectors = 0;
        }
-       bitmap->allclean = 0;
        return 0;
 }
+EXPORT_SYMBOL(bitmap_startwrite);
 
 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
                     int success, int behind)
 {
-       if (!bitmap) return;
+       if (!bitmap)
+               return;
        if (behind) {
-               atomic_dec(&bitmap->behind_writes);
-               PRINTK(KERN_DEBUG "dec write-behind count %d/%d\n",
-                 atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
+               if (atomic_dec_and_test(&bitmap->behind_writes))
+                       wake_up(&bitmap->behind_wait);
+               pr_debug("dec write-behind count %d/%lu\n",
+                        atomic_read(&bitmap->behind_writes),
+                        bitmap->mddev->bitmap_info.max_write_behind);
        }
 
        while (sectors) {
-               int blocks;
+               sector_t blocks;
                unsigned long flags;
                bitmap_counter_t *bmc;
 
@@ -1318,34 +1406,40 @@ void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long secto
                        return;
                }
 
-               if (success &&
+               if (success && !bitmap->mddev->degraded &&
                    bitmap->events_cleared < bitmap->mddev->events) {
                        bitmap->events_cleared = bitmap->mddev->events;
                        bitmap->need_sync = 1;
+                       sysfs_notify_dirent_safe(bitmap->sysfs_can_clear);
                }
 
-               if (!success && ! (*bmc & NEEDED_MASK))
+               if (!success && !NEEDED(*bmc))
                        *bmc |= NEEDED_MASK;
 
-               if ((*bmc & COUNTER_MAX) == COUNTER_MAX)
+               if (COUNTER(*bmc) == COUNTER_MAX)
                        wake_up(&bitmap->overflow_wait);
 
                (*bmc)--;
                if (*bmc <= 2) {
                        set_page_attr(bitmap,
-                                     filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
-                                     BITMAP_PAGE_CLEAN);
+                                     filemap_get_page(
+                                             bitmap,
+                                             offset >> CHUNK_BLOCK_SHIFT(bitmap)),
+                                     BITMAP_PAGE_PENDING);
+                       bitmap->allclean = 0;
                }
                spin_unlock_irqrestore(&bitmap->lock, flags);
                offset += blocks;
                if (sectors > blocks)
                        sectors -= blocks;
-               else sectors = 0;
+               else
+                       sectors = 0;
        }
 }
+EXPORT_SYMBOL(bitmap_endwrite);
 
-int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
-                       int degraded)
+static int __bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
+                              int degraded)
 {
        bitmap_counter_t *bmc;
        int rv;
@@ -1369,17 +1463,39 @@ int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
                }
        }
        spin_unlock_irq(&bitmap->lock);
-       bitmap->allclean = 0;
        return rv;
 }
 
-void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int aborted)
+int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
+                     int degraded)
+{
+       /* bitmap_start_sync must always report on multiples of whole
+        * pages, otherwise resync (which is very PAGE_SIZE based) will
+        * get confused.
+        * So call __bitmap_start_sync repeatedly (if needed) until
+        * At least PAGE_SIZE>>9 blocks are covered.
+        * Return the 'or' of the result.
+        */
+       int rv = 0;
+       sector_t blocks1;
+
+       *blocks = 0;
+       while (*blocks < (PAGE_SIZE>>9)) {
+               rv |= __bitmap_start_sync(bitmap, offset,
+                                         &blocks1, degraded);
+               offset += blocks1;
+               *blocks += blocks1;
+       }
+       return rv;
+}
+EXPORT_SYMBOL(bitmap_start_sync);
+
+void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks, int aborted)
 {
        bitmap_counter_t *bmc;
        unsigned long flags;
-/*
-       if (offset == 0) printk("bitmap_end_sync 0 (%d)\n", aborted);
-*/     if (bitmap == NULL) {
+
+       if (bitmap == NULL) {
                *blocks = 1024;
                return;
        }
@@ -1388,9 +1504,6 @@ void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int ab
        if (bmc == NULL)
                goto unlock;
        /* locked */
-/*
-       if (offset == 0) printk("bitmap_end sync found 0x%x, blocks %d\n", *bmc, *blocks);
-*/
        if (RESYNC(*bmc)) {
                *bmc &= ~RESYNC_MASK;
 
@@ -1400,14 +1513,15 @@ void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int ab
                        if (*bmc <= 2) {
                                set_page_attr(bitmap,
                                              filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
-                                             BITMAP_PAGE_CLEAN);
+                                             BITMAP_PAGE_PENDING);
+                               bitmap->allclean = 0;
                        }
                }
        }
  unlock:
        spin_unlock_irqrestore(&bitmap->lock, flags);
-       bitmap->allclean = 0;
 }
+EXPORT_SYMBOL(bitmap_end_sync);
 
 void bitmap_close_sync(struct bitmap *bitmap)
 {
@@ -1416,7 +1530,7 @@ void bitmap_close_sync(struct bitmap *bitmap)
         * RESYNC bit wherever it is still on
         */
        sector_t sector = 0;
-       int blocks;
+       sector_t blocks;
        if (!bitmap)
                return;
        while (sector < bitmap->mddev->resync_max_sectors) {
@@ -1424,11 +1538,12 @@ void bitmap_close_sync(struct bitmap *bitmap)
                sector += blocks;
        }
 }
+EXPORT_SYMBOL(bitmap_close_sync);
 
 void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector)
 {
        sector_t s = 0;
-       int blocks;
+       sector_t blocks;
 
        if (!bitmap)
                return;
@@ -1437,11 +1552,13 @@ void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector)
                return;
        }
        if (time_before(jiffies, (bitmap->last_end_sync
-                                 + bitmap->daemon_sleep * HZ)))
+                                 + bitmap->mddev->bitmap_info.daemon_sleep)))
                return;
        wait_event(bitmap->mddev->recovery_wait,
                   atomic_read(&bitmap->mddev->recovery_active) == 0);
 
+       bitmap->mddev->curr_resync_completed = sector;
+       set_bit(MD_CHANGE_CLEAN, &bitmap->mddev->flags);
        sector &= ~((1ULL << CHUNK_BLOCK_SHIFT(bitmap)) - 1);
        s = 0;
        while (s < sector && s < bitmap->mddev->resync_max_sectors) {
@@ -1449,7 +1566,9 @@ void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector)
                s += blocks;
        }
        bitmap->last_end_sync = jiffies;
+       sysfs_notify(&bitmap->mddev->kobj, NULL, "sync_completed");
 }
+EXPORT_SYMBOL(bitmap_cond_end_sync);
 
 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
 {
@@ -1458,7 +1577,7 @@ static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int n
         * be 0 at this point
         */
 
-       int secs;
+       sector_t secs;
        bitmap_counter_t *bmc;
        spin_lock_irq(&bitmap->lock);
        bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
@@ -1466,15 +1585,15 @@ static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int n
                spin_unlock_irq(&bitmap->lock);
                return;
        }
-       if (! *bmc) {
+       if (!*bmc) {
                struct page *page;
-               *bmc = 1 | (needed?NEEDED_MASK:0);
+               *bmc = 1 | (needed ? NEEDED_MASK : 0);
                bitmap_count_page(bitmap, offset, 1);
                page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));
-               set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
+               set_page_attr(bitmap, page, BITMAP_PAGE_PENDING);
+               bitmap->allclean = 0;
        }
        spin_unlock_irq(&bitmap->lock);
-       bitmap->allclean = 0;
 }
 
 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
@@ -1483,19 +1602,27 @@ void bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
        unsigned long chunk;
 
        for (chunk = s; chunk <= e; chunk++) {
-               sector_t sec = chunk << CHUNK_BLOCK_SHIFT(bitmap);
+               sector_t sec = (sector_t)chunk << CHUNK_BLOCK_SHIFT(bitmap);
                bitmap_set_memory_bits(bitmap, sec, 1);
+               spin_lock_irq(&bitmap->lock);
                bitmap_file_set_bit(bitmap, sec);
+               spin_unlock_irq(&bitmap->lock);
+               if (sec < bitmap->mddev->recovery_cp)
+                       /* We are asserting that the array is dirty,
+                        * so move the recovery_cp address back so
+                        * that it is obvious that it is dirty
+                        */
+                       bitmap->mddev->recovery_cp = sec;
        }
 }
 
 /*
  * flush out any pending updates
  */
-void bitmap_flush(mddev_t *mddev)
+void bitmap_flush(struct mddev *mddev)
 {
        struct bitmap *bitmap = mddev->bitmap;
-       int sleep;
+       long sleep;
 
        if (!bitmap) /* there was no bitmap */
                return;
@@ -1503,12 +1630,13 @@ void bitmap_flush(mddev_t *mddev)
        /* run the daemon_work three time to ensure everything is flushed
         * that can be
         */
-       sleep = bitmap->daemon_sleep;
-       bitmap->daemon_sleep = 0;
-       bitmap_daemon_work(bitmap);
-       bitmap_daemon_work(bitmap);
-       bitmap_daemon_work(bitmap);
-       bitmap->daemon_sleep = sleep;
+       sleep = mddev->bitmap_info.daemon_sleep * 2;
+       bitmap->daemon_lastrun -= sleep;
+       bitmap_daemon_work(mddev);
+       bitmap->daemon_lastrun -= sleep;
+       bitmap_daemon_work(mddev);
+       bitmap->daemon_lastrun -= sleep;
+       bitmap_daemon_work(mddev);
        bitmap_update_sb(bitmap);
 }
 
@@ -1538,17 +1666,23 @@ static void bitmap_free(struct bitmap *bitmap)
        kfree(bp);
        kfree(bitmap);
 }
-void bitmap_destroy(mddev_t *mddev)
+
+void bitmap_destroy(struct mddev *mddev)
 {
        struct bitmap *bitmap = mddev->bitmap;
 
        if (!bitmap) /* there was no bitmap */
                return;
 
+       mutex_lock(&mddev->bitmap_info.mutex);
        mddev->bitmap = NULL; /* disconnect from the md device */
+       mutex_unlock(&mddev->bitmap_info.mutex);
        if (mddev->thread)
                mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
 
+       if (bitmap->sysfs_can_clear)
+               sysfs_put(bitmap->sysfs_can_clear);
+
        bitmap_free(bitmap);
 }
 
@@ -1556,22 +1690,23 @@ void bitmap_destroy(mddev_t *mddev)
  * initialize the bitmap structure
  * if this returns an error, bitmap_destroy must be called to do clean up
  */
-int bitmap_create(mddev_t *mddev)
+int bitmap_create(struct mddev *mddev)
 {
        struct bitmap *bitmap;
-       unsigned long blocks = mddev->resync_max_sectors;
+       sector_t blocks = mddev->resync_max_sectors;
        unsigned long chunks;
        unsigned long pages;
-       struct file *file = mddev->bitmap_file;
+       struct file *file = mddev->bitmap_info.file;
        int err;
-       sector_t start;
+       struct sysfs_dirent *bm = NULL;
 
        BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
 
-       if (!file && !mddev->bitmap_offset) /* bitmap disabled, nothing to do */
+       if (!file
+           && !mddev->bitmap_info.offset) /* bitmap disabled, nothing to do */
                return 0;
 
-       BUG_ON(file && mddev->bitmap_offset);
+       BUG_ON(file && mddev->bitmap_info.offset);
 
        bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
        if (!bitmap)
@@ -1581,81 +1716,406 @@ int bitmap_create(mddev_t *mddev)
        atomic_set(&bitmap->pending_writes, 0);
        init_waitqueue_head(&bitmap->write_wait);
        init_waitqueue_head(&bitmap->overflow_wait);
+       init_waitqueue_head(&bitmap->behind_wait);
 
        bitmap->mddev = mddev;
 
+       if (mddev->kobj.sd)
+               bm = sysfs_get_dirent(mddev->kobj.sd, NULL, "bitmap");
+       if (bm) {
+               bitmap->sysfs_can_clear = sysfs_get_dirent(bm, NULL, "can_clear");
+               sysfs_put(bm);
+       } else
+               bitmap->sysfs_can_clear = NULL;
+
        bitmap->file = file;
-       bitmap->offset = mddev->bitmap_offset;
        if (file) {
                get_file(file);
-               do_sync_mapping_range(file->f_mapping, 0, LLONG_MAX,
-                                     SYNC_FILE_RANGE_WAIT_BEFORE |
-                                     SYNC_FILE_RANGE_WRITE |
-                                     SYNC_FILE_RANGE_WAIT_AFTER);
+               /* As future accesses to this file will use bmap,
+                * and bypass the page cache, we must sync the file
+                * first.
+                */
+               vfs_fsync(file, 1);
+       }
+       /* read superblock from bitmap file (this sets mddev->bitmap_info.chunksize) */
+       if (!mddev->bitmap_info.external) {
+               /*
+                * If 'MD_ARRAY_FIRST_USE' is set, then device-mapper is
+                * instructing us to create a new on-disk bitmap instance.
+                */
+               if (test_and_clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags))
+                       err = bitmap_new_disk_sb(bitmap);
+               else
+                       err = bitmap_read_sb(bitmap);
+       } else {
+               err = 0;
+               if (mddev->bitmap_info.chunksize == 0 ||
+                   mddev->bitmap_info.daemon_sleep == 0)
+                       /* chunksize and time_base need to be
+                        * set first. */
+                       err = -EINVAL;
        }
-       /* read superblock from bitmap file (this sets bitmap->chunksize) */
-       err = bitmap_read_sb(bitmap);
        if (err)
                goto error;
 
-       bitmap->chunkshift = ffz(~bitmap->chunksize);
+       bitmap->daemon_lastrun = jiffies;
+       bitmap->chunkshift = ffz(~mddev->bitmap_info.chunksize);
 
        /* now that chunksize and chunkshift are set, we can use these macros */
-       chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) /
-                       CHUNK_BLOCK_RATIO(bitmap);
-       pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
+       chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) >>
+                       CHUNK_BLOCK_SHIFT(bitmap);
+       pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
 
        BUG_ON(!pages);
 
        bitmap->chunks = chunks;
        bitmap->pages = pages;
        bitmap->missing_pages = pages;
-       bitmap->counter_bits = COUNTER_BITS;
-
-       bitmap->syncchunk = ~0UL;
 
-#ifdef INJECT_FATAL_FAULT_1
-       bitmap->bp = NULL;
-#else
        bitmap->bp = kzalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
-#endif
+
        err = -ENOMEM;
        if (!bitmap->bp)
                goto error;
 
-       /* now that we have some pages available, initialize the in-memory
-        * bitmap from the on-disk bitmap */
-       start = 0;
+       printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
+               pages, bmname(bitmap));
+
+       mddev->bitmap = bitmap;
+
+
+       return (bitmap->flags & BITMAP_WRITE_ERROR) ? -EIO : 0;
+
+ error:
+       bitmap_free(bitmap);
+       return err;
+}
+
+int bitmap_load(struct mddev *mddev)
+{
+       int err = 0;
+       sector_t start = 0;
+       sector_t sector = 0;
+       struct bitmap *bitmap = mddev->bitmap;
+
+       if (!bitmap)
+               goto out;
+
+       /* Clear out old bitmap info first:  Either there is none, or we
+        * are resuming after someone else has possibly changed things,
+        * so we should forget old cached info.
+        * All chunks should be clean, but some might need_sync.
+        */
+       while (sector < mddev->resync_max_sectors) {
+               sector_t blocks;
+               bitmap_start_sync(bitmap, sector, &blocks, 0);
+               sector += blocks;
+       }
+       bitmap_close_sync(bitmap);
+
        if (mddev->degraded == 0
            || bitmap->events_cleared == mddev->events)
-               /* no need to keep dirty bits to optimise a re-add of a missing device */
+               /* no need to keep dirty bits to optimise a
+                * re-add of a missing device */
                start = mddev->recovery_cp;
+
+       mutex_lock(&mddev->bitmap_info.mutex);
        err = bitmap_init_from_disk(bitmap, start);
+       mutex_unlock(&mddev->bitmap_info.mutex);
 
        if (err)
-               goto error;
+               goto out;
 
-       printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
-               pages, bmname(bitmap));
+       mddev->thread->timeout = mddev->bitmap_info.daemon_sleep;
+       md_wakeup_thread(mddev->thread);
 
-       mddev->bitmap = bitmap;
+       bitmap_update_sb(bitmap);
 
-       mddev->thread->timeout = bitmap->daemon_sleep * HZ;
+       if (bitmap->flags & BITMAP_WRITE_ERROR)
+               err = -EIO;
+out:
+       return err;
+}
+EXPORT_SYMBOL_GPL(bitmap_load);
 
-       bitmap_update_sb(bitmap);
+static ssize_t
+location_show(struct mddev *mddev, char *page)
+{
+       ssize_t len;
+       if (mddev->bitmap_info.file)
+               len = sprintf(page, "file");
+       else if (mddev->bitmap_info.offset)
+               len = sprintf(page, "%+lld", (long long)mddev->bitmap_info.offset);
+       else
+               len = sprintf(page, "none");
+       len += sprintf(page+len, "\n");
+       return len;
+}
 
-       return (bitmap->flags & BITMAP_WRITE_ERROR) ? -EIO : 0;
+static ssize_t
+location_store(struct mddev *mddev, const char *buf, size_t len)
+{
 
- error:
-       bitmap_free(bitmap);
-       return err;
+       if (mddev->pers) {
+               if (!mddev->pers->quiesce)
+                       return -EBUSY;
+               if (mddev->recovery || mddev->sync_thread)
+                       return -EBUSY;
+       }
+
+       if (mddev->bitmap || mddev->bitmap_info.file ||
+           mddev->bitmap_info.offset) {
+               /* bitmap already configured.  Only option is to clear it */
+               if (strncmp(buf, "none", 4) != 0)
+                       return -EBUSY;
+               if (mddev->pers) {
+                       mddev->pers->quiesce(mddev, 1);
+                       bitmap_destroy(mddev);
+                       mddev->pers->quiesce(mddev, 0);
+               }
+               mddev->bitmap_info.offset = 0;
+               if (mddev->bitmap_info.file) {
+                       struct file *f = mddev->bitmap_info.file;
+                       mddev->bitmap_info.file = NULL;
+                       restore_bitmap_write_access(f);
+                       fput(f);
+               }
+       } else {
+               /* No bitmap, OK to set a location */
+               long long offset;
+               if (strncmp(buf, "none", 4) == 0)
+                       /* nothing to be done */;
+               else if (strncmp(buf, "file:", 5) == 0) {
+                       /* Not supported yet */
+                       return -EINVAL;
+               } else {
+                       int rv;
+                       if (buf[0] == '+')
+                               rv = strict_strtoll(buf+1, 10, &offset);
+                       else
+                               rv = strict_strtoll(buf, 10, &offset);
+                       if (rv)
+                               return rv;
+                       if (offset == 0)
+                               return -EINVAL;
+                       if (mddev->bitmap_info.external == 0 &&
+                           mddev->major_version == 0 &&
+                           offset != mddev->bitmap_info.default_offset)
+                               return -EINVAL;
+                       mddev->bitmap_info.offset = offset;
+                       if (mddev->pers) {
+                               mddev->pers->quiesce(mddev, 1);
+                               rv = bitmap_create(mddev);
+                               if (!rv)
+                                       rv = bitmap_load(mddev);
+                               if (rv) {
+                                       bitmap_destroy(mddev);
+                                       mddev->bitmap_info.offset = 0;
+                               }
+                               mddev->pers->quiesce(mddev, 0);
+                               if (rv)
+                                       return rv;
+                       }
+               }
+       }
+       if (!mddev->external) {
+               /* Ensure new bitmap info is stored in
+                * metadata promptly.
+                */
+               set_bit(MD_CHANGE_DEVS, &mddev->flags);
+               md_wakeup_thread(mddev->thread);
+       }
+       return len;
 }
 
-/* the bitmap API -- for raid personalities */
-EXPORT_SYMBOL(bitmap_startwrite);
-EXPORT_SYMBOL(bitmap_endwrite);
-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);
+static struct md_sysfs_entry bitmap_location =
+__ATTR(location, S_IRUGO|S_IWUSR, location_show, location_store);
+
+static ssize_t
+timeout_show(struct mddev *mddev, char *page)
+{
+       ssize_t len;
+       unsigned long secs = mddev->bitmap_info.daemon_sleep / HZ;
+       unsigned long jifs = mddev->bitmap_info.daemon_sleep % HZ;
+
+       len = sprintf(page, "%lu", secs);
+       if (jifs)
+               len += sprintf(page+len, ".%03u", jiffies_to_msecs(jifs));
+       len += sprintf(page+len, "\n");
+       return len;
+}
+
+static ssize_t
+timeout_store(struct mddev *mddev, const char *buf, size_t len)
+{
+       /* timeout can be set at any time */
+       unsigned long timeout;
+       int rv = strict_strtoul_scaled(buf, &timeout, 4);
+       if (rv)
+               return rv;
+
+       /* just to make sure we don't overflow... */
+       if (timeout >= LONG_MAX / HZ)
+               return -EINVAL;
+
+       timeout = timeout * HZ / 10000;
+
+       if (timeout >= MAX_SCHEDULE_TIMEOUT)
+               timeout = MAX_SCHEDULE_TIMEOUT-1;
+       if (timeout < 1)
+               timeout = 1;
+       mddev->bitmap_info.daemon_sleep = timeout;
+       if (mddev->thread) {
+               /* if thread->timeout is MAX_SCHEDULE_TIMEOUT, then
+                * the bitmap is all clean and we don't need to
+                * adjust the timeout right now
+                */
+               if (mddev->thread->timeout < MAX_SCHEDULE_TIMEOUT) {
+                       mddev->thread->timeout = timeout;
+                       md_wakeup_thread(mddev->thread);
+               }
+       }
+       return len;
+}
+
+static struct md_sysfs_entry bitmap_timeout =
+__ATTR(time_base, S_IRUGO|S_IWUSR, timeout_show, timeout_store);
+
+static ssize_t
+backlog_show(struct mddev *mddev, char *page)
+{
+       return sprintf(page, "%lu\n", mddev->bitmap_info.max_write_behind);
+}
+
+static ssize_t
+backlog_store(struct mddev *mddev, const char *buf, size_t len)
+{
+       unsigned long backlog;
+       int rv = strict_strtoul(buf, 10, &backlog);
+       if (rv)
+               return rv;
+       if (backlog > COUNTER_MAX)
+               return -EINVAL;
+       mddev->bitmap_info.max_write_behind = backlog;
+       return len;
+}
+
+static struct md_sysfs_entry bitmap_backlog =
+__ATTR(backlog, S_IRUGO|S_IWUSR, backlog_show, backlog_store);
+
+static ssize_t
+chunksize_show(struct mddev *mddev, char *page)
+{
+       return sprintf(page, "%lu\n", mddev->bitmap_info.chunksize);
+}
+
+static ssize_t
+chunksize_store(struct mddev *mddev, const char *buf, size_t len)
+{
+       /* Can only be changed when no bitmap is active */
+       int rv;
+       unsigned long csize;
+       if (mddev->bitmap)
+               return -EBUSY;
+       rv = strict_strtoul(buf, 10, &csize);
+       if (rv)
+               return rv;
+       if (csize < 512 ||
+           !is_power_of_2(csize))
+               return -EINVAL;
+       mddev->bitmap_info.chunksize = csize;
+       return len;
+}
+
+static struct md_sysfs_entry bitmap_chunksize =
+__ATTR(chunksize, S_IRUGO|S_IWUSR, chunksize_show, chunksize_store);
+
+static ssize_t metadata_show(struct mddev *mddev, char *page)
+{
+       return sprintf(page, "%s\n", (mddev->bitmap_info.external
+                                     ? "external" : "internal"));
+}
+
+static ssize_t metadata_store(struct mddev *mddev, const char *buf, size_t len)
+{
+       if (mddev->bitmap ||
+           mddev->bitmap_info.file ||
+           mddev->bitmap_info.offset)
+               return -EBUSY;
+       if (strncmp(buf, "external", 8) == 0)
+               mddev->bitmap_info.external = 1;
+       else if (strncmp(buf, "internal", 8) == 0)
+               mddev->bitmap_info.external = 0;
+       else
+               return -EINVAL;
+       return len;
+}
+
+static struct md_sysfs_entry bitmap_metadata =
+__ATTR(metadata, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
+
+static ssize_t can_clear_show(struct mddev *mddev, char *page)
+{
+       int len;
+       if (mddev->bitmap)
+               len = sprintf(page, "%s\n", (mddev->bitmap->need_sync ?
+                                            "false" : "true"));
+       else
+               len = sprintf(page, "\n");
+       return len;
+}
+
+static ssize_t can_clear_store(struct mddev *mddev, const char *buf, size_t len)
+{
+       if (mddev->bitmap == NULL)
+               return -ENOENT;
+       if (strncmp(buf, "false", 5) == 0)
+               mddev->bitmap->need_sync = 1;
+       else if (strncmp(buf, "true", 4) == 0) {
+               if (mddev->degraded)
+                       return -EBUSY;
+               mddev->bitmap->need_sync = 0;
+       } else
+               return -EINVAL;
+       return len;
+}
+
+static struct md_sysfs_entry bitmap_can_clear =
+__ATTR(can_clear, S_IRUGO|S_IWUSR, can_clear_show, can_clear_store);
+
+static ssize_t
+behind_writes_used_show(struct mddev *mddev, char *page)
+{
+       if (mddev->bitmap == NULL)
+               return sprintf(page, "0\n");
+       return sprintf(page, "%lu\n",
+                      mddev->bitmap->behind_writes_used);
+}
+
+static ssize_t
+behind_writes_used_reset(struct mddev *mddev, const char *buf, size_t len)
+{
+       if (mddev->bitmap)
+               mddev->bitmap->behind_writes_used = 0;
+       return len;
+}
+
+static struct md_sysfs_entry max_backlog_used =
+__ATTR(max_backlog_used, S_IRUGO | S_IWUSR,
+       behind_writes_used_show, behind_writes_used_reset);
+
+static struct attribute *md_bitmap_attrs[] = {
+       &bitmap_location.attr,
+       &bitmap_timeout.attr,
+       &bitmap_backlog.attr,
+       &bitmap_chunksize.attr,
+       &bitmap_metadata.attr,
+       &bitmap_can_clear.attr,
+       &max_backlog_used.attr,
+       NULL
+};
+struct attribute_group md_bitmap_group = {
+       .name = "bitmap",
+       .attrs = md_bitmap_attrs,
+};
+