1 files changed, 167 insertions, 317 deletions

diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index f8ffaee20ff..ecc56765d94 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -7,7 +7,6 @@
  * additions, Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.:
  * - added disk storage for bitmap
  * - changes to allow various bitmap chunk sizes
- * - added bitmap daemon (to asynchronously clear bitmap bits from disk)
  */
 
 /*
@@ -15,16 +14,12 @@
  *
  * flush after percent set rather than just time based. (maybe both).
  * wait if count gets too high, wake when it drops to half.
- * allow bitmap to be mirrored with superblock (before or after...)
- * allow hot-add to re-instate a current device.
- * allow hot-add of bitmap after quiessing device
  */
 
 #include <linux/module.h>
 #include <linux/errno.h>
 #include <linux/slab.h>
 #include <linux/init.h>
-#include <linux/config.h>
 #include <linux/timer.h>
 #include <linux/sched.h>
 #include <linux/list.h>
@@ -73,24 +68,6 @@ static inline char * bmname(struct bitmap *bitmap)
 
 
 /*
- * test if the bitmap is active
- */
-int bitmap_active(struct bitmap *bitmap)
-{
-        unsigned long flags;
-        int res = 0;
-
-        if (!bitmap)
-                return res;
-        spin_lock_irqsave(&bitmap->lock, flags);
-        res = bitmap->flags & BITMAP_ACTIVE;
-        spin_unlock_irqrestore(&bitmap->lock, flags);
-        return res;
-}
-
-#define WRITE_POOL_SIZE 256
-
-/*
  * just a placeholder - calls kmalloc for bitmap pages
  */
 static unsigned char *bitmap_alloc_page(struct bitmap *bitmap)
@@ -269,6 +246,8 @@ static struct page *read_sb_page(mddev_t *mddev, long offset, unsigned long inde
 
                 if (sync_page_io(rdev->bdev, target, PAGE_SIZE, page, READ)) {
                         page->index = index;
+                        attach_page_buffers(page, NULL); /* so that free_buffer will
+                                                          * quietly no-op */
                         return page;
                 }
         }
@@ -300,77 +279,132 @@ static int write_sb_page(mddev_t *mddev, long offset, struct page *page, int wai
  */
 static int write_page(struct bitmap *bitmap, struct page *page, int wait)
 {
-        int ret = -ENOMEM;
+        struct buffer_head *bh;
 
         if (bitmap->file == NULL)
                 return write_sb_page(bitmap->mddev, bitmap->offset, page, wait);
 
-        flush_dcache_page(page); /* make sure visible to anyone reading the file */
+        bh = page_buffers(page);
 
-        if (wait)
-                lock_page(page);
-        else {
-                if (TestSetPageLocked(page))
-                        return -EAGAIN; /* already locked */
-                if (PageWriteback(page)) {
-                        unlock_page(page);
-                        return -EAGAIN;
-                }
+        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;
         }
 
-        ret = page->mapping->a_ops->prepare_write(bitmap->file, page, 0, PAGE_SIZE);
-        if (!ret)
-                ret = page->mapping->a_ops->commit_write(bitmap->file, page, 0,
-                        PAGE_SIZE);
-        if (ret) {
-                unlock_page(page);
-                return ret;
+        if (wait) {
+                wait_event(bitmap->write_wait,
+                           atomic_read(&bitmap->pending_writes)==0);
+                return (bitmap->flags & BITMAP_WRITE_ERROR) ? -EIO : 0;
         }
+        return 0;
+}
 
-        set_page_dirty(page); /* force it to be written out */
-
-        if (!wait) {
-                /* add to list to be waited for by daemon */
-                struct page_list *item = mempool_alloc(bitmap->write_pool, GFP_NOIO);
-                item->page = page;
-                get_page(page);
-                spin_lock(&bitmap->write_lock);
-                list_add(&item->list, &bitmap->complete_pages);
-                spin_unlock(&bitmap->write_lock);
-                md_wakeup_thread(bitmap->writeback_daemon);
+static void end_bitmap_write(struct buffer_head *bh, int uptodate)
+{
+        struct bitmap *bitmap = bh->b_private;
+        unsigned long flags;
+
+        if (!uptodate) {
+                spin_lock_irqsave(&bitmap->lock, flags);
+                bitmap->flags |= BITMAP_WRITE_ERROR;
+                spin_unlock_irqrestore(&bitmap->lock, flags);
+        }
+        if (atomic_dec_and_test(&bitmap->pending_writes))
+                wake_up(&bitmap->write_wait);
+}
+
+/* copied from buffer.c */
+static void
+__clear_page_buffers(struct page *page)
+{
+        ClearPagePrivate(page);
+        set_page_private(page, 0);
+        page_cache_release(page);
+}
+static void free_buffers(struct page *page)
+{
+        struct buffer_head *bh = page_buffers(page);
+
+        while (bh) {
+                struct buffer_head *next = bh->b_this_page;
+                free_buffer_head(bh);
+                bh = next;
         }
-        return write_one_page(page, wait);
+        __clear_page_buffers(page);
+        put_page(page);
 }
 
-/* read a page from a file, pinning it into cache, and return bytes_read */
+/* read a page from a file.
+ * We both read the page, and attach buffers to the page to record the
+ * address of each block (using bmap).  These addresses will be used
+ * to write the block later, completely bypassing the filesystem.
+ * This usage is similar to how swap files are handled, and allows us
+ * to write to a file with no concerns of memory allocation failing.
+ */
 static struct page *read_page(struct file *file, unsigned long index,
-                                        unsigned long *bytes_read)
+                              struct bitmap *bitmap,
+                              unsigned long count)
 {
-        struct inode *inode = file->f_mapping->host;
         struct page *page = NULL;
-        loff_t isize = i_size_read(inode);
-        unsigned long end_index = isize >> PAGE_SHIFT;
+        struct inode *inode = file->f_dentry->d_inode;
+        struct buffer_head *bh;
+        sector_t block;
 
         PRINTK("read bitmap file (%dB @ %Lu)\n", (int)PAGE_SIZE,
                         (unsigned long long)index << PAGE_SHIFT);
 
-        page = read_cache_page(inode->i_mapping, index,
-                        (filler_t *)inode->i_mapping->a_ops->readpage, file);
+        page = alloc_page(GFP_KERNEL);
+        if (!page)
+                page = ERR_PTR(-ENOMEM);
         if (IS_ERR(page))
                 goto out;
-        wait_on_page_locked(page);
-        if (!PageUptodate(page) || PageError(page)) {
+
+        bh = alloc_page_buffers(page, 1<<inode->i_blkbits, 0);
+        if (!bh) {
                 put_page(page);
-                page = ERR_PTR(-EIO);
+                page = ERR_PTR(-ENOMEM);
                 goto out;
         }
+        attach_page_buffers(page, bh);
+        block = index << (PAGE_SHIFT - inode->i_blkbits);
+        while (bh) {
+                if (count == 0)
+                        bh->b_blocknr = 0;
+                else {
+                        bh->b_blocknr = bmap(inode, block);
+                        if (bh->b_blocknr == 0) {
+                                /* Cannot use this file! */
+                                free_buffers(page);
+                                page = ERR_PTR(-EINVAL);
+                                goto out;
+                        }
+                        bh->b_bdev = inode->i_sb->s_bdev;
+                        if (count < (1<<inode->i_blkbits))
+                                count = 0;
+                        else
+                                count -= (1<<inode->i_blkbits);
+
+                        bh->b_end_io = end_bitmap_write;
+                        bh->b_private = bitmap;
+                        atomic_inc(&bitmap->pending_writes);
+                        set_buffer_locked(bh);
+                        set_buffer_mapped(bh);
+                        submit_bh(READ, bh);
+                }
+                block++;
+                bh = bh->b_this_page;
+        }
+        page->index = index;
 
-        if (index > end_index) /* we have read beyond EOF */
-                *bytes_read = 0;
-        else if (index == end_index) /* possible short read */
-                *bytes_read = isize & ~PAGE_MASK;
-        else
-                *bytes_read = PAGE_SIZE; /* got a full page */
+        wait_event(bitmap->write_wait,
+                   atomic_read(&bitmap->pending_writes)==0);
+        if (bitmap->flags & BITMAP_WRITE_ERROR) {
+                free_buffers(page);
+                page = ERR_PTR(-EIO);
+        }
 out:
         if (IS_ERR(page))
                 printk(KERN_ALERT "md: bitmap read error: (%dB @ %Lu): %ld\n",
@@ -441,16 +475,14 @@ static int bitmap_read_sb(struct bitmap *bitmap)
         char *reason = NULL;
         bitmap_super_t *sb;
         unsigned long chunksize, daemon_sleep, write_behind;
-        unsigned long bytes_read;
         unsigned long long events;
         int err = -EINVAL;
 
         /* page 0 is the superblock, read it... */
         if (bitmap->file)
-                bitmap->sb_page = read_page(bitmap->file, 0, &bytes_read);
+                bitmap->sb_page = read_page(bitmap->file, 0, bitmap, PAGE_SIZE);
         else {
                 bitmap->sb_page = read_sb_page(bitmap->mddev, bitmap->offset, 0);
-                bytes_read = PAGE_SIZE;
         }
         if (IS_ERR(bitmap->sb_page)) {
                 err = PTR_ERR(bitmap->sb_page);
@@ -460,13 +492,6 @@ static int bitmap_read_sb(struct bitmap *bitmap)
 
         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
 
-        if (bytes_read < sizeof(*sb)) { /* short read */
-                printk(KERN_INFO "%s: bitmap file superblock truncated\n",
-                        bmname(bitmap));
-                err = -ENOSPC;
-                goto out;
-        }
-
         chunksize = le32_to_cpu(sb->chunksize);
         daemon_sleep = le32_to_cpu(sb->daemon_sleep);
         write_behind = le32_to_cpu(sb->write_behind);
@@ -550,7 +575,6 @@ static void bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
                 spin_unlock_irqrestore(&bitmap->lock, flags);
                 return;
         }
-        get_page(bitmap->sb_page);
         spin_unlock_irqrestore(&bitmap->lock, flags);
         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
         switch (op) {
@@ -561,7 +585,6 @@ static void bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
                 default: BUG();
         }
         kunmap_atomic(sb, KM_USER0);
-        put_page(bitmap->sb_page);
 }
 
 /*
@@ -614,48 +637,17 @@ static void bitmap_file_unmap(struct bitmap *bitmap)
 
         while (pages--)
                 if (map[pages]->index != 0) /* 0 is sb_page, release it below */
-                        put_page(map[pages]);
+                        free_buffers(map[pages]);
         kfree(map);
         kfree(attr);
 
-        safe_put_page(sb_page);
-}
-
-static void bitmap_stop_daemon(struct bitmap *bitmap);
-
-/* dequeue the next item in a page list -- don't call from irq context */
-static struct page_list *dequeue_page(struct bitmap *bitmap)
-{
-        struct page_list *item = NULL;
-        struct list_head *head = &bitmap->complete_pages;
-
-        spin_lock(&bitmap->write_lock);
-        if (list_empty(head))
-                goto out;
-        item = list_entry(head->prev, struct page_list, list);
-        list_del(head->prev);
-out:
-        spin_unlock(&bitmap->write_lock);
-        return item;
-}
-
-static void drain_write_queues(struct bitmap *bitmap)
-{
-        struct page_list *item;
-
-        while ((item = dequeue_page(bitmap))) {
-                /* don't bother to wait */
-                put_page(item->page);
-                mempool_free(item, bitmap->write_pool);
-        }
-
-        wake_up(&bitmap->write_wait);
+        if (sb_page)
+                free_buffers(sb_page);
 }
 
 static void bitmap_file_put(struct bitmap *bitmap)
 {
         struct file *file;
-        struct inode *inode;
         unsigned long flags;
 
         spin_lock_irqsave(&bitmap->lock, flags);
@@ -663,17 +655,14 @@ static void bitmap_file_put(struct bitmap *bitmap)
         bitmap->file = NULL;
         spin_unlock_irqrestore(&bitmap->lock, flags);
 
-        bitmap_stop_daemon(bitmap);
-
-        drain_write_queues(bitmap);
-
+        if (file)
+                wait_event(bitmap->write_wait,
+                           atomic_read(&bitmap->pending_writes)==0);
         bitmap_file_unmap(bitmap);
 
         if (file) {
-                inode = file->f_mapping->host;
-                spin_lock(&inode->i_lock);
-                atomic_set(&inode->i_writecount, 1); /* allow writes again */
-                spin_unlock(&inode->i_lock);
+                struct inode *inode = file->f_dentry->d_inode;
+                invalidate_inode_pages(inode->i_mapping);
                 fput(file);
         }
 }
@@ -708,26 +697,27 @@ static void bitmap_file_kick(struct bitmap *bitmap)
 }
 
 enum bitmap_page_attr {
-        BITMAP_PAGE_DIRTY = 1, // there are set bits that need to be synced
-        BITMAP_PAGE_CLEAN = 2, // there are bits that might need to be cleared
-        BITMAP_PAGE_NEEDWRITE=4, // there are cleared bits that need to be synced
+        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
 };
 
 static inline void set_page_attr(struct bitmap *bitmap, struct page *page,
                                 enum bitmap_page_attr attr)
 {
-        bitmap->filemap_attr[page->index] |= attr;
+        __set_bit((page->index<<2) + attr, bitmap->filemap_attr);
 }
 
 static inline void clear_page_attr(struct bitmap *bitmap, struct page *page,
                                 enum bitmap_page_attr attr)
 {
-        bitmap->filemap_attr[page->index] &= ~attr;
+        __clear_bit((page->index<<2) + attr, bitmap->filemap_attr);
 }
 
-static inline unsigned long get_page_attr(struct bitmap *bitmap, struct page *page)
+static inline unsigned long test_page_attr(struct bitmap *bitmap, struct page *page,
+                                           enum bitmap_page_attr attr)
 {
-        return bitmap->filemap_attr[page->index];
+        return test_bit((page->index<<2) + attr, bitmap->filemap_attr);
 }
 
 /*
@@ -751,11 +741,6 @@ static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
         page = filemap_get_page(bitmap, chunk);
         bit = file_page_offset(chunk);
 
-
-        /* make sure the page stays cached until it gets written out */
-        if (! (get_page_attr(bitmap, page) & BITMAP_PAGE_DIRTY))
-                get_page(page);
-
         /* set the bit */
         kaddr = kmap_atomic(page, KM_USER0);
         if (bitmap->flags & BITMAP_HOSTENDIAN)
@@ -775,7 +760,8 @@ static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
  * sync the dirty pages of the bitmap file to disk */
 int bitmap_unplug(struct bitmap *bitmap)
 {
-        unsigned long i, attr, flags;
+        unsigned long i, flags;
+        int dirty, need_write;
         struct page *page;
         int wait = 0;
         int err;
@@ -792,35 +778,26 @@ int bitmap_unplug(struct bitmap *bitmap)
                         return 0;
                 }
                 page = bitmap->filemap[i];
-                attr = get_page_attr(bitmap, page);
+                dirty = test_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
+                need_write = test_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
                 clear_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
                 clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
-                if ((attr & BITMAP_PAGE_DIRTY))
+                if (dirty)
                         wait = 1;
                 spin_unlock_irqrestore(&bitmap->lock, flags);
 
-                if (attr & (BITMAP_PAGE_DIRTY | BITMAP_PAGE_NEEDWRITE)) {
+                if (dirty | need_write)
                         err = write_page(bitmap, page, 0);
-                        if (err == -EAGAIN) {
-                                if (attr & BITMAP_PAGE_DIRTY)
-                                        err = write_page(bitmap, page, 1);
-                                else
-                                        err = 0;
-                        }
-                        if (err)
-                                return 1;
-                }
         }
         if (wait) { /* if any writes were performed, we need to wait on them */
-                if (bitmap->file) {
-                        spin_lock_irq(&bitmap->write_lock);
-                        wait_event_lock_irq(bitmap->write_wait,
-                                            list_empty(&bitmap->complete_pages), bitmap->write_lock,
-                                            wake_up_process(bitmap->writeback_daemon->tsk));
-                        spin_unlock_irq(&bitmap->write_lock);
-                } else
+                if (bitmap->file)
+                        wait_event(bitmap->write_wait,
+                                   atomic_read(&bitmap->pending_writes)==0);
+                else
                         md_super_wait(bitmap->mddev);
         }
+        if (bitmap->flags & BITMAP_WRITE_ERROR)
+                bitmap_file_kick(bitmap);
         return 0;
 }
 
@@ -842,7 +819,7 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
         struct page *page = NULL, *oldpage = NULL;
         unsigned long num_pages, bit_cnt = 0;
         struct file *file;
-        unsigned long bytes, offset, dummy;
+        unsigned long bytes, offset;
         int outofdate;
         int ret = -ENOSPC;
         void *paddr;
@@ -879,7 +856,12 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
         if (!bitmap->filemap)
                 goto out;
 
-        bitmap->filemap_attr = kzalloc(sizeof(long) * num_pages, GFP_KERNEL);
+        /* We need 4 bits per page, rounded up to a multiple of sizeof(unsigned long) */
+        bitmap->filemap_attr = kzalloc(
+                (((num_pages*4/8)+sizeof(unsigned long)-1)
+                 /sizeof(unsigned long))
+                *sizeof(unsigned long),
+                GFP_KERNEL);
         if (!bitmap->filemap_attr)
                 goto out;
 
@@ -890,7 +872,12 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
                 index = file_page_index(i);
                 bit = file_page_offset(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 - index * PAGE_SIZE;
+                        else
+                                count = PAGE_SIZE;
                         if (index == 0) {
                                 /*
                                  * if we're here then the superblock page
@@ -900,7 +887,7 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
                                 page = bitmap->sb_page;
                                 offset = sizeof(bitmap_super_t);
                         } else if (file) {
-                                page = read_page(file, index, &dummy);
+                                page = read_page(file, index, bitmap, count);
                                 offset = 0;
                         } else {
                                 page = read_sb_page(bitmap->mddev, bitmap->offset, index);
@@ -971,12 +958,11 @@ void bitmap_write_all(struct bitmap *bitmap)
         /* We don't actually write all bitmap blocks here,
          * just flag them as needing to be written
          */
+        int i;
 
-        unsigned long chunks = bitmap->chunks;
-        unsigned long bytes = (chunks+7)/8 + sizeof(bitmap_super_t);
-        unsigned long num_pages = (bytes + PAGE_SIZE-1) / PAGE_SIZE;
-        while (num_pages--)
-                bitmap->filemap_attr[num_pages] |= BITMAP_PAGE_NEEDWRITE;
+        for (i=0; i < bitmap->file_pages; i++)
+                set_page_attr(bitmap, bitmap->filemap[i],
+                              BITMAP_PAGE_NEEDWRITE);
 }
 
 
@@ -1007,7 +993,6 @@ int bitmap_daemon_work(struct bitmap *bitmap)
         struct page *page = NULL, *lastpage = NULL;
         int err = 0;
         int blocks;
-        int attr;
         void *paddr;
 
         if (bitmap == NULL)
@@ -1029,43 +1014,34 @@ int bitmap_daemon_work(struct bitmap *bitmap)
 
                 if (page != lastpage) {
                         /* skip this page unless it's marked as needing cleaning */
-                        if (!((attr=get_page_attr(bitmap, page)) & BITMAP_PAGE_CLEAN)) {
-                                if (attr & BITMAP_PAGE_NEEDWRITE) {
-                                        get_page(page);
+                        if (!test_page_attr(bitmap, page, BITMAP_PAGE_CLEAN)) {
+                                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 (attr & BITMAP_PAGE_NEEDWRITE) {
+                                if (need_write) {
                                         switch (write_page(bitmap, page, 0)) {
-                                        case -EAGAIN:
-                                                set_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
-                                                break;
                                         case 0:
                                                 break;
                                         default:
                                                 bitmap_file_kick(bitmap);
                                         }
-                                        put_page(page);
                                 }
                                 continue;
                         }
 
                         /* grab the new page, sync and release the old */
-                        get_page(page);
                         if (lastpage != NULL) {
-                                if (get_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);
                                         err = write_page(bitmap, lastpage, 0);
-                                        if (err == -EAGAIN) {
-                                                err = 0;
-                                                set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
-                                        }
                                 } else {
                                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
                                         spin_unlock_irqrestore(&bitmap->lock, flags);
                                 }
-                                put_page(lastpage);
                                 if (err)
                                         bitmap_file_kick(bitmap);
                         } else
@@ -1107,131 +1083,19 @@ int bitmap_daemon_work(struct bitmap *bitmap)
         /* now sync the final page */
         if (lastpage != NULL) {
                 spin_lock_irqsave(&bitmap->lock, flags);
-                if (get_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);
                         err = write_page(bitmap, lastpage, 0);
-                        if (err == -EAGAIN) {
-                                set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
-                                err = 0;
-                        }
                 } else {
                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
                         spin_unlock_irqrestore(&bitmap->lock, flags);
                 }
-
-                put_page(lastpage);
         }
 
         return err;
 }
 
-static void daemon_exit(struct bitmap *bitmap, mdk_thread_t **daemon)
-{
-        mdk_thread_t *dmn;
-        unsigned long flags;
-
-        /* if no one is waiting on us, we'll free the md thread struct
-         * and exit, otherwise we let the waiter clean things up */
-        spin_lock_irqsave(&bitmap->lock, flags);
-        if ((dmn = *daemon)) { /* no one is waiting, cleanup and exit */
-                *daemon = NULL;
-                spin_unlock_irqrestore(&bitmap->lock, flags);
-                kfree(dmn);
-                complete_and_exit(NULL, 0); /* do_exit not exported */
-        }
-        spin_unlock_irqrestore(&bitmap->lock, flags);
-}
-
-static void bitmap_writeback_daemon(mddev_t *mddev)
-{
-        struct bitmap *bitmap = mddev->bitmap;
-        struct page *page;
-        struct page_list *item;
-        int err = 0;
-
-        if (signal_pending(current)) {
-                printk(KERN_INFO
-                       "%s: bitmap writeback daemon got signal, exiting...\n",
-                       bmname(bitmap));
-                err = -EINTR;
-                goto out;
-        }
-        if (bitmap == NULL)
-                /* about to be stopped. */
-                return;
-
-        PRINTK("%s: bitmap writeback daemon woke up...\n", bmname(bitmap));
-        /* wait on bitmap page writebacks */
-        while ((item = dequeue_page(bitmap))) {
-                page = item->page;
-                mempool_free(item, bitmap->write_pool);
-                PRINTK("wait on page writeback: %p\n", page);
-                wait_on_page_writeback(page);
-                PRINTK("finished page writeback: %p\n", page);
-
-                err = PageError(page);
-                put_page(page);
-                if (err) {
-                        printk(KERN_WARNING "%s: bitmap file writeback "
-                               "failed (page %lu): %d\n",
-                               bmname(bitmap), page->index, err);
-                        bitmap_file_kick(bitmap);
-                        goto out;
-                }
-        }
- out:
-        wake_up(&bitmap->write_wait);
-        if (err) {
-                printk(KERN_INFO "%s: bitmap writeback daemon exiting (%d)\n",
-                       bmname(bitmap), err);
-                daemon_exit(bitmap, &bitmap->writeback_daemon);
-        }
-}
-
-static mdk_thread_t *bitmap_start_daemon(struct bitmap *bitmap,
-                                void (*func)(mddev_t *), char *name)
-{
-        mdk_thread_t *daemon;
-        char namebuf[32];
-
-#ifdef INJECT_FATAL_FAULT_2
-        daemon = NULL;
-#else
-        sprintf(namebuf, "%%s_%s", name);
-        daemon = md_register_thread(func, bitmap->mddev, namebuf);
-#endif
-        if (!daemon) {
-                printk(KERN_ERR "%s: failed to start bitmap daemon\n",
-                        bmname(bitmap));
-                return ERR_PTR(-ECHILD);
-        }
-
-        md_wakeup_thread(daemon); /* start it running */
-
-        PRINTK("%s: %s daemon (pid %d) started...\n",
-                bmname(bitmap), name, daemon->tsk->pid);
-
-        return daemon;
-}
-
-static void bitmap_stop_daemon(struct bitmap *bitmap)
-{
-        /* the daemon can't stop itself... it'll just exit instead... */
-        if (bitmap->writeback_daemon && ! IS_ERR(bitmap->writeback_daemon) &&
-            current->pid != bitmap->writeback_daemon->tsk->pid) {
-                mdk_thread_t *daemon;
-                unsigned long flags;
-
-                spin_lock_irqsave(&bitmap->lock, flags);
-                daemon = bitmap->writeback_daemon;
-                bitmap->writeback_daemon = NULL;
-                spin_unlock_irqrestore(&bitmap->lock, flags);
-                if (daemon && ! IS_ERR(daemon))
-                        md_unregister_thread(daemon); /* destroy the thread */
-        }
-}
-
 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
                                             sector_t offset, int *blocks,
                                             int create)
@@ -1500,8 +1364,6 @@ static void bitmap_free(struct bitmap *bitmap)
 
         /* free all allocated memory */
 
-        mempool_destroy(bitmap->write_pool);
-
         if (bp) /* deallocate the page memory */
                 for (k = 0; k < pages; k++)
                         if (bp[k].map && !bp[k].hijacked)
@@ -1549,20 +1411,20 @@ int bitmap_create(mddev_t *mddev)
                 return -ENOMEM;
 
         spin_lock_init(&bitmap->lock);
-        bitmap->mddev = mddev;
-
-        spin_lock_init(&bitmap->write_lock);
-        INIT_LIST_HEAD(&bitmap->complete_pages);
+        atomic_set(&bitmap->pending_writes, 0);
         init_waitqueue_head(&bitmap->write_wait);
-        bitmap->write_pool = mempool_create_kmalloc_pool(WRITE_POOL_SIZE,
-                                                sizeof(struct page_list));
-        err = -ENOMEM;
-        if (!bitmap->write_pool)
-                goto error;
+
+        bitmap->mddev = mddev;
 
         bitmap->file = file;
         bitmap->offset = mddev->bitmap_offset;
-        if (file) get_file(file);
+        if (file) {
+                get_file(file);
+                do_sync_file_range(file, 0, LLONG_MAX,
+                                   SYNC_FILE_RANGE_WAIT_BEFORE |
+                                   SYNC_FILE_RANGE_WRITE |
+                                   SYNC_FILE_RANGE_WAIT_AFTER);
+        }
         /* read superblock from bitmap file (this sets bitmap->chunksize) */
         err = bitmap_read_sb(bitmap);
         if (err)
@@ -1594,8 +1456,6 @@ int bitmap_create(mddev_t *mddev)
         if (!bitmap->bp)
                 goto error;
 
-        bitmap->flags |= BITMAP_ACTIVE;
-
         /* now that we have some pages available, initialize the in-memory
          * bitmap from the on-disk bitmap */
         start = 0;
@@ -1613,15 +1473,6 @@ int bitmap_create(mddev_t *mddev)
 
         mddev->bitmap = bitmap;
 
-        if (file)
-                /* kick off the bitmap writeback daemon */
-                bitmap->writeback_daemon =
-                        bitmap_start_daemon(bitmap,
-                                            bitmap_writeback_daemon,
-                                            "bitmap_wb");
-
-        if (IS_ERR(bitmap->writeback_daemon))
-                return PTR_ERR(bitmap->writeback_daemon);
         mddev->thread->timeout = bitmap->daemon_sleep * HZ;
 
         return bitmap_update_sb(bitmap);
@@ -1638,4 +1489,3 @@ EXPORT_SYMBOL(bitmap_start_sync);
 EXPORT_SYMBOL(bitmap_end_sync);
 EXPORT_SYMBOL(bitmap_unplug);
 EXPORT_SYMBOL(bitmap_close_sync);
-EXPORT_SYMBOL(bitmap_daemon_work);