dm snapshot: create function for chunk_is_tracked wait
[safe/jmp/linux-2.6] / drivers / md / bitmap.c
index bedd66e..60e2b32 100644 (file)
  * 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/init.h>
-#include <linux/config.h>
 #include <linux/timer.h>
 #include <linux/sched.h>
 #include <linux/list.h>
 #include <linux/file.h>
 #include <linux/mount.h>
 #include <linux/buffer_head.h>
-#include <linux/raid/md.h>
-#include <linux/raid/bitmap.h>
+#include "md.h"
+#include "bitmap.h"
 
 /* debug macros */
 
@@ -108,13 +108,16 @@ static void bitmap_free_page(struct bitmap *bitmap, unsigned char *page)
  * allocated while we're using it
  */
 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;
        }
 
@@ -204,49 +207,38 @@ static void bitmap_checkfree(struct bitmap *bitmap, unsigned long page)
  * bitmap file handling - read and write the bitmap file and its superblock
  */
 
-/* copy the pathname of a file to a buffer */
-char *file_path(struct file *file, char *buf, int count)
-{
-       struct dentry *d;
-       struct vfsmount *v;
-
-       if (!buf)
-               return NULL;
-
-       d = file->f_dentry;
-       v = file->f_vfsmnt;
-
-       buf = d_path(d, v, buf, count);
-
-       return IS_ERR(buf) ? NULL : buf;
-}
-
 /*
  * basic page I/O operations
  */
 
 /* IO operations when bitmap is stored near all superblocks */
-static struct page *read_sb_page(mddev_t *mddev, long offset, unsigned long index)
+static struct page *read_sb_page(mddev_t *mddev, long offset,
+                                struct page *page,
+                                unsigned long index, int size)
 {
        /* choose a good rdev and read the page from there */
 
        mdk_rdev_t *rdev;
-       struct list_head *tmp;
-       struct page *page = alloc_page(GFP_KERNEL);
        sector_t target;
 
        if (!page)
+               page = alloc_page(GFP_KERNEL);
+       if (!page)
                return ERR_PTR(-ENOMEM);
 
-       ITERATE_RDEV(mddev, rdev, tmp) {
+       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_offset << 1) + offset + index * (PAGE_SIZE/512);
+               target = rdev->sb_start + offset + index * (PAGE_SIZE/512);
 
-               if (sync_page_io(rdev->bdev, target, PAGE_SIZE, page, READ)) {
+               if (sync_page_io(rdev->bdev, target,
+                                roundup(size, bdev_logical_block_size(rdev->bdev)),
+                                page, READ)) {
                        page->index = index;
+                       attach_page_buffers(page, NULL); /* so that free_buffer will
+                                                         * quietly no-op */
                        return page;
                }
        }
@@ -254,51 +246,122 @@ static struct page *read_sb_page(mddev_t *mddev, long offset, unsigned long inde
 
 }
 
-static int write_sb_page(mddev_t *mddev, long offset, struct page *page, int wait)
+static mdk_rdev_t *next_active_rdev(mdk_rdev_t *rdev, mddev_t *mddev)
 {
-       mdk_rdev_t *rdev;
-       struct list_head *tmp;
+       /* Iterate the disks of an mddev, using rcu to protect access to the
+        * linked list, and raising the refcount of devices we return to ensure
+        * they don't disappear while in use.
+        * As devices are only added or removed when raid_disk is < 0 and
+        * nr_pending is 0 and In_sync is clear, the entries we return will
+        * still be in the same position on the list when we re-enter
+        * list_for_each_continue_rcu.
+        */
+       struct list_head *pos;
+       rcu_read_lock();
+       if (rdev == NULL)
+               /* start at the beginning */
+               pos = &mddev->disks;
+       else {
+               /* release the previous rdev and start from there. */
+               rdev_dec_pending(rdev, mddev);
+               pos = &rdev->same_set;
+       }
+       list_for_each_continue_rcu(pos, &mddev->disks) {
+               rdev = list_entry(pos, mdk_rdev_t, same_set);
+               if (rdev->raid_disk >= 0 &&
+                   !test_bit(Faulty, &rdev->flags)) {
+                       /* this is a usable devices */
+                       atomic_inc(&rdev->nr_pending);
+                       rcu_read_unlock();
+                       return rdev;
+               }
+       }
+       rcu_read_unlock();
+       return NULL;
+}
 
-       ITERATE_RDEV(mddev, rdev, tmp)
-               if (test_bit(In_sync, &rdev->flags)
-                   && !test_bit(Faulty, &rdev->flags))
+static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
+{
+       mdk_rdev_t *rdev = NULL;
+       mddev_t *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_logical_block_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->dev_sectors
+                                   > 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_offset<<1) + offset
+                                      rdev->sb_start + bitmap->offset
                                       + page->index * (PAGE_SIZE/512),
-                                      PAGE_SIZE,
+                                      size,
                                       page);
+       }
 
        if (wait)
                md_super_wait(mddev);
        return 0;
+
+ bad_alignment:
+       return -EINVAL;
 }
 
+static void bitmap_file_kick(struct bitmap *bitmap);
 /*
  * write out a page to a file
  */
-static int write_page(struct bitmap *bitmap, struct page *page, int wait)
+static void write_page(struct bitmap *bitmap, struct page *page, int wait)
 {
        struct buffer_head *bh;
 
-       if (bitmap->file == NULL)
-               return write_sb_page(bitmap->mddev, bitmap->offset, page, wait);
+       if (bitmap->file == NULL) {
+               switch (write_sb_page(bitmap, page, wait)) {
+               case -EINVAL:
+                       bitmap->flags |= BITMAP_WRITE_ERROR;
+               }
+       } else {
 
-       bh = page_buffers(page);
+               bh = page_buffers(page);
 
-       while (bh && bh->b_blocknr) {
-               atomic_inc(&bitmap->pending_writes);
-               set_buffer_locked(bh);
-               set_buffer_mapped(bh);
-               submit_bh(WRITE, bh);
-               bh = bh->b_this_page;
-       }
+               while (bh && bh->b_blocknr) {
+                       atomic_inc(&bitmap->pending_writes);
+                       set_buffer_locked(bh);
+                       set_buffer_mapped(bh);
+                       submit_bh(WRITE, bh);
+                       bh = bh->b_this_page;
+               }
 
-       if (wait) {
-               wait_event(bitmap->write_wait,
-                          atomic_read(&bitmap->pending_writes)==0);
-               return (bitmap->flags & BITMAP_WRITE_ERROR) ? -EIO : 0;
+               if (wait) {
+                       wait_event(bitmap->write_wait,
+                                  atomic_read(&bitmap->pending_writes)==0);
+               }
        }
-       return 0;
+       if (bitmap->flags & BITMAP_WRITE_ERROR)
+               bitmap_file_kick(bitmap);
 }
 
 static void end_bitmap_write(struct buffer_head *bh, int uptodate)
@@ -348,12 +411,9 @@ static struct page *read_page(struct file *file, unsigned long index,
                              unsigned long count)
 {
        struct page *page = NULL;
-       struct inode *inode = file->f_dentry->d_inode;
-       loff_t pos = index << PAGE_SHIFT;
-       int ret;
+       struct inode *inode = file->f_path.dentry->d_inode;
        struct buffer_head *bh;
        sector_t block;
-       mm_segment_t oldfs;
 
        PRINTK("read bitmap file (%dB @ %Lu)\n", (int)PAGE_SIZE,
                        (unsigned long long)index << PAGE_SHIFT);
@@ -364,18 +424,6 @@ static struct page *read_page(struct file *file, unsigned long index,
        if (IS_ERR(page))
                goto out;
 
-       oldfs = get_fs();
-       set_fs(KERNEL_DS);
-       ret = vfs_read(file, (char __user*) page_address(page), count, &pos);
-       set_fs(oldfs);
-
-       if (ret >= 0 && ret != count)
-               ret = -EIO;
-       if (ret < 0) {
-               put_page(page);
-               page = ERR_PTR(ret);
-               goto out;
-       }
        bh = alloc_page_buffers(page, 1<<inode->i_blkbits, 0);
        if (!bh) {
                put_page(page);
@@ -403,12 +451,22 @@ static struct page *read_page(struct file *file, unsigned long index,
 
                        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;
+
+       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",
@@ -423,25 +481,28 @@ out:
  */
 
 /* update the event counter and sync the superblock to disk */
-int bitmap_update_sb(struct bitmap *bitmap)
+void bitmap_update_sb(struct bitmap *bitmap)
 {
        bitmap_super_t *sb;
        unsigned long flags;
 
        if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
-               return 0;
+               return;
        spin_lock_irqsave(&bitmap->lock, flags);
        if (!bitmap->sb_page) { /* no superblock */
                spin_unlock_irqrestore(&bitmap->lock, flags);
-               return 0;
+               return;
        }
        spin_unlock_irqrestore(&bitmap->lock, flags);
        sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
        sb->events = cpu_to_le64(bitmap->mddev->events);
-       if (!bitmap->mddev->degraded)
-               sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
+       if (bitmap->mddev->events < bitmap->events_cleared) {
+               /* rocking back to read-only */
+               bitmap->events_cleared = bitmap->mddev->events;
+               sb->events_cleared = cpu_to_le64(bitmap->events_cleared);
+       }
        kunmap_atomic(sb, KM_USER0);
-       return write_page(bitmap, bitmap->sb_page, 1);
+       write_page(bitmap, bitmap->sb_page, 1);
 }
 
 /* print out the bitmap file superblock */
@@ -483,10 +544,15 @@ static int bitmap_read_sb(struct bitmap *bitmap)
        int err = -EINVAL;
 
        /* page 0 is the superblock, read it... */
-       if (bitmap->file)
-               bitmap->sb_page = read_page(bitmap->file, 0, bitmap, PAGE_SIZE);
-       else {
-               bitmap->sb_page = read_sb_page(bitmap->mddev, bitmap->offset, 0);
+       if (bitmap->file) {
+               loff_t isize = i_size_read(bitmap->file->f_mapping->host);
+               int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
+
+               bitmap->sb_page = read_page(bitmap->file, 0, bitmap, bytes);
+       } else {
+               bitmap->sb_page = read_sb_page(bitmap->mddev, bitmap->offset,
+                                              NULL,
+                                              0, sizeof(bitmap_super_t));
        }
        if (IS_ERR(bitmap->sb_page)) {
                err = PTR_ERR(bitmap->sb_page);
@@ -506,7 +572,7 @@ 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)
                reason = "bitmap chunksize not a power of 2";
@@ -540,7 +606,7 @@ static int bitmap_read_sb(struct bitmap *bitmap)
                printk(KERN_INFO "%s: bitmap file is out of date (%llu < %llu) "
                        "-- forcing full recovery\n", bmname(bitmap), events,
                        (unsigned long long) bitmap->mddev->events);
-               sb->state |= BITMAP_STALE;
+               sb->state |= cpu_to_le32(BITMAP_STALE);
        }
 success:
        /* assign fields using values from superblock */
@@ -548,11 +614,11 @@ success:
        bitmap->daemon_sleep = daemon_sleep;
        bitmap->daemon_lastrun = jiffies;
        bitmap->max_write_behind = write_behind;
-       bitmap->flags |= sb->state;
+       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 & BITMAP_STALE)
+       if (sb->state & cpu_to_le32(BITMAP_STALE))
                bitmap->events_cleared = bitmap->mddev->events;
        err = 0;
 out:
@@ -567,28 +633,31 @@ enum bitmap_mask_op {
        MASK_UNSET
 };
 
-/* record the state of the bitmap in the superblock */
-static void bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
-                               enum bitmap_mask_op op)
+/* record the state of the bitmap in the superblock.  Return the old value */
+static int bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
+                            enum bitmap_mask_op op)
 {
        bitmap_super_t *sb;
        unsigned long flags;
+       int old;
 
        spin_lock_irqsave(&bitmap->lock, flags);
        if (!bitmap->sb_page) { /* can't set the state */
                spin_unlock_irqrestore(&bitmap->lock, flags);
-               return;
+               return 0;
        }
        spin_unlock_irqrestore(&bitmap->lock, flags);
        sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
+       old = le32_to_cpu(sb->state) & bits;
        switch (op) {
-               case MASK_SET: sb->state |= bits;
+               case MASK_SET: sb->state |= cpu_to_le32(bits);
                                break;
-               case MASK_UNSET: sb->state &= ~bits;
+               case MASK_UNSET: sb->state &= cpu_to_le32(~bits);
                                break;
                default: BUG();
        }
        kunmap_atomic(sb, KM_USER0);
+       return old;
 }
 
 /*
@@ -617,6 +686,7 @@ static inline unsigned long file_page_offset(unsigned long chunk)
 static inline struct page *filemap_get_page(struct bitmap *bitmap,
                                        unsigned long chunk)
 {
+       if (file_page_index(chunk) >= bitmap->file_pages) return NULL;
        return bitmap->filemap[file_page_index(chunk) - file_page_index(0)];
 }
 
@@ -665,8 +735,8 @@ static void bitmap_file_put(struct bitmap *bitmap)
        bitmap_file_unmap(bitmap);
 
        if (file) {
-               struct inode *inode = file->f_dentry->d_inode;
-               invalidate_inode_pages(inode->i_mapping);
+               struct inode *inode = file->f_path.dentry->d_inode;
+               invalidate_mapping_pages(inode->i_mapping, 0, -1);
                fput(file);
        }
 }
@@ -681,18 +751,25 @@ static void bitmap_file_kick(struct bitmap *bitmap)
 {
        char *path, *ptr = NULL;
 
-       bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET);
-       bitmap_update_sb(bitmap);
+       if (bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET) == 0) {
+               bitmap_update_sb(bitmap);
+
+               if (bitmap->file) {
+                       path = kmalloc(PAGE_SIZE, GFP_KERNEL);
+                       if (path)
+                               ptr = d_path(&bitmap->file->f_path, path,
+                                            PAGE_SIZE);
 
-       if (bitmap->file) {
-               path = kmalloc(PAGE_SIZE, GFP_KERNEL);
-               if (path)
-                       ptr = file_path(bitmap->file, path, PAGE_SIZE);
 
-               printk(KERN_ALERT "%s: kicking failed bitmap file %s from array!\n",
-                      bmname(bitmap), ptr ? ptr : "");
+                       printk(KERN_ALERT
+                             "%s: kicking failed bitmap file %s from array!\n",
+                             bmname(bitmap), IS_ERR(ptr) ? "" : ptr);
 
-               kfree(path);
+                       kfree(path);
+               } else
+                       printk(KERN_ALERT
+                              "%s: disabling internal bitmap due to errors\n",
+                              bmname(bitmap));
        }
 
        bitmap_file_put(bitmap);
@@ -743,6 +820,7 @@ static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
        }
 
        page = filemap_get_page(bitmap, chunk);
+       if (!page) return;
        bit = file_page_offset(chunk);
 
        /* set the bit */
@@ -762,16 +840,15 @@ static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 /* this gets called when the md device is ready to unplug its underlying
  * (slave) device queues -- before we let any writes go down, we need to
  * sync the dirty pages of the bitmap file to disk */
-int bitmap_unplug(struct bitmap *bitmap)
+void bitmap_unplug(struct bitmap *bitmap)
 {
        unsigned long i, flags;
        int dirty, need_write;
        struct page *page;
        int wait = 0;
-       int err;
 
        if (!bitmap)
-               return 0;
+               return;
 
        /* look at each page to see if there are any set bits that need to be
         * flushed out to disk */
@@ -779,7 +856,7 @@ int bitmap_unplug(struct bitmap *bitmap)
                spin_lock_irqsave(&bitmap->lock, flags);
                if (!bitmap->filemap) {
                        spin_unlock_irqrestore(&bitmap->lock, flags);
-                       return 0;
+                       return;
                }
                page = bitmap->filemap[i];
                dirty = test_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
@@ -791,7 +868,7 @@ int bitmap_unplug(struct bitmap *bitmap)
                spin_unlock_irqrestore(&bitmap->lock, flags);
 
                if (dirty | need_write)
-                       err = write_page(bitmap, page, 0);
+                       write_page(bitmap, page, 0);
        }
        if (wait) { /* if any writes were performed, we need to wait on them */
                if (bitmap->file)
@@ -802,7 +879,6 @@ int bitmap_unplug(struct bitmap *bitmap)
        }
        if (bitmap->flags & BITMAP_WRITE_ERROR)
                bitmap_file_kick(bitmap);
-       return 0;
 }
 
 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
@@ -851,23 +927,21 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
                        bmname(bitmap),
                        (unsigned long) i_size_read(file->f_mapping->host),
                        bytes + sizeof(bitmap_super_t));
-               goto out;
+               goto err;
        }
 
        ret = -ENOMEM;
 
        bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
        if (!bitmap->filemap)
-               goto out;
+               goto err;
 
        /* We need 4 bits per page, rounded up to a multiple of sizeof(unsigned long) */
        bitmap->filemap_attr = kzalloc(
-               (((num_pages*4/8)+sizeof(unsigned long)-1)
-                /sizeof(unsigned long))
-               *sizeof(unsigned long),
+               roundup( DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
                GFP_KERNEL);
        if (!bitmap->filemap_attr)
-               goto out;
+               goto err;
 
        oldindex = ~0L;
 
@@ -879,7 +953,8 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
                        int count;
                        /* unmap the old page, we're done with it */
                        if (index == num_pages-1)
-                               count = bytes - index * PAGE_SIZE;
+                               count = bytes + sizeof(bitmap_super_t)
+                                       - index * PAGE_SIZE;
                        else
                                count = PAGE_SIZE;
                        if (index == 0) {
@@ -890,21 +965,31 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
                                 */
                                page = bitmap->sb_page;
                                offset = sizeof(bitmap_super_t);
+                               if (!file)
+                                       read_sb_page(bitmap->mddev,
+                                                    bitmap->offset,
+                                                    page,
+                                                    index, count);
                        } else if (file) {
                                page = read_page(file, index, bitmap, count);
                                offset = 0;
                        } else {
-                               page = read_sb_page(bitmap->mddev, bitmap->offset, index);
+                               page = read_sb_page(bitmap->mddev, bitmap->offset,
+                                                   NULL,
+                                                   index, count);
                                offset = 0;
                        }
                        if (IS_ERR(page)) { /* read error */
                                ret = PTR_ERR(page);
-                               goto out;
+                               goto err;
                        }
 
                        oldindex = index;
                        oldpage = page;
 
+                       bitmap->filemap[bitmap->file_pages++] = page;
+                       bitmap->last_page_size = count;
+
                        if (outofdate) {
                                /*
                                 * if bitmap is out of date, dirty the
@@ -914,15 +999,12 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
                                memset(paddr + offset, 0xff,
                                       PAGE_SIZE - offset);
                                kunmap_atomic(paddr, KM_USER0);
-                               ret = write_page(bitmap, page, 1);
-                               if (ret) {
-                                       /* release, page not in filemap yet */
-                                       put_page(page);
-                                       goto out;
-                               }
-                       }
+                               write_page(bitmap, page, 1);
 
-                       bitmap->filemap[bitmap->file_pages++] = page;
+                               ret = -EIO;
+                               if (bitmap->flags & BITMAP_WRITE_ERROR)
+                                       goto err;
+                       }
                }
                paddr = kmap_atomic(page, KM_USER0);
                if (bitmap->flags & BITMAP_HOSTENDIAN)
@@ -932,9 +1014,11 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
                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);
                }
@@ -949,11 +1033,15 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
                md_wakeup_thread(bitmap->mddev->thread);
        }
 
-out:
        printk(KERN_INFO "%s: bitmap initialized from disk: "
-               "read %lu/%lu pages, set %lu bits, status: %d\n",
-               bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt, ret);
+               "read %lu/%lu pages, set %lu bits\n",
+               bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt);
 
+       return 0;
+
+ err:
+       printk(KERN_INFO "%s: bitmap initialisation failed: %d\n",
+              bmname(bitmap), ret);
        return ret;
 }
 
@@ -990,29 +1078,32 @@ static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
  *                     out to disk
  */
 
-int bitmap_daemon_work(struct bitmap *bitmap)
+void bitmap_daemon_work(struct bitmap *bitmap)
 {
        unsigned long j;
        unsigned long flags;
        struct page *page = NULL, *lastpage = NULL;
-       int err = 0;
        int blocks;
        void *paddr;
 
        if (bitmap == NULL)
-               return 0;
+               return;
        if (time_before(jiffies, bitmap->daemon_lastrun + bitmap->daemon_sleep*HZ))
-               return 0;
+               goto done;
+
        bitmap->daemon_lastrun = jiffies;
+       if (bitmap->allclean) {
+               bitmap->mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
+               return;
+       }
+       bitmap->allclean = 1;
 
+       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);
 
@@ -1026,13 +1117,11 @@ int bitmap_daemon_work(struct bitmap *bitmap)
 
                                spin_unlock_irqrestore(&bitmap->lock, flags);
                                if (need_write) {
-                                       switch (write_page(bitmap, page, 0)) {
-                                       case 0:
-                                               break;
-                                       default:
-                                               bitmap_file_kick(bitmap);
-                                       }
+                                       write_page(bitmap, page, 0);
+                                       bitmap->allclean = 0;
                                }
+                               spin_lock_irqsave(&bitmap->lock, flags);
+                               j |= (PAGE_BITS - 1);
                                continue;
                        }
 
@@ -1041,35 +1130,48 @@ int bitmap_daemon_work(struct bitmap *bitmap)
                                if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
                                        clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
                                        spin_unlock_irqrestore(&bitmap->lock, flags);
-                                       err = write_page(bitmap, lastpage, 0);
+                                       write_page(bitmap, lastpage, 0);
                                } else {
                                        set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
                                        spin_unlock_irqrestore(&bitmap->lock, flags);
                                }
-                               if (err)
-                                       bitmap_file_kick(bitmap);
                        } else
                                spin_unlock_irqrestore(&bitmap->lock, flags);
                        lastpage = page;
-/*
-                       printk("bitmap clean at page %lu\n", j);
-*/
+
+                       /* We are possibly going to clear some bits, so make
+                        * sure that events_cleared is up-to-date.
+                        */
+                       if (bitmap->need_sync) {
+                               bitmap_super_t *sb;
+                               bitmap->need_sync = 0;
+                               sb = kmap_atomic(bitmap->sb_page, KM_USER0);
+                               sb->events_cleared =
+                                       cpu_to_le64(bitmap->events_cleared);
+                               kunmap_atomic(sb, KM_USER0);
+                               write_page(bitmap, bitmap->sb_page, 1);
+                       }
                        spin_lock_irqsave(&bitmap->lock, flags);
                        clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
                }
-               bmc = bitmap_get_counter(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
-                                       &blocks, 0);
+               bmc = bitmap_get_counter(bitmap,
+                                        (sector_t)j << CHUNK_BLOCK_SHIFT(bitmap),
+                                        &blocks, 0);
                if (bmc) {
 /*
   if (j < 100) printk("bitmap: j=%lu, *bmc = 0x%x\n", j, *bmc);
 */
+                       if (*bmc)
+                               bitmap->allclean = 0;
+
                        if (*bmc == 2) {
                                *bmc=1; /* maybe clear the bit next time */
                                set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
                        } else if (*bmc == 1) {
                                /* 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 */
@@ -1080,9 +1182,10 @@ int bitmap_daemon_work(struct bitmap *bitmap)
                                        ext2_clear_bit(file_page_offset(j), paddr);
                                kunmap_atomic(paddr, KM_USER0);
                        }
-               }
-               spin_unlock_irqrestore(&bitmap->lock, flags);
+               } else
+                       j |= PAGE_COUNTER_MASK;
        }
+       spin_unlock_irqrestore(&bitmap->lock, flags);
 
        /* now sync the final page */
        if (lastpage != NULL) {
@@ -1090,19 +1193,23 @@ int bitmap_daemon_work(struct bitmap *bitmap)
                if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
                        clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
                        spin_unlock_irqrestore(&bitmap->lock, flags);
-                       err = write_page(bitmap, lastpage, 0);
+                       write_page(bitmap, lastpage, 0);
                } else {
                        set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
                        spin_unlock_irqrestore(&bitmap->lock, flags);
                }
        }
 
-       return err;
+ done:
+       if (bitmap->allclean == 0)
+               bitmap->mddev->thread->timeout = bitmap->daemon_sleep * HZ;
 }
 
 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
                                            sector_t offset, int *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.
@@ -1158,16 +1265,31 @@ int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sect
                        return 0;
                }
 
+               if (unlikely((*bmc & COUNTER_MAX) == 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
+                        * the spinlock.
+                        */
+                       prepare_to_wait(&bitmap->overflow_wait, &__wait,
+                                       TASK_UNINTERRUPTIBLE);
+                       spin_unlock_irq(&bitmap->lock);
+                       blk_unplug(bitmap->mddev->queue);
+                       schedule();
+                       finish_wait(&bitmap->overflow_wait, &__wait);
+                       continue;
+               }
+
                switch(*bmc) {
                case 0:
                        bitmap_file_set_bit(bitmap, offset);
                        bitmap_count_page(bitmap,offset, 1);
-                       blk_plug_device(bitmap->mddev->queue);
+                       blk_plug_device_unlocked(bitmap->mddev->queue);
                        /* fall through */
                case 1:
                        *bmc = 2;
                }
-               BUG_ON((*bmc & COUNTER_MAX) == COUNTER_MAX);
+
                (*bmc)++;
 
                spin_unlock_irq(&bitmap->lock);
@@ -1177,6 +1299,7 @@ int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sect
                        sectors -= blocks;
                else sectors = 0;
        }
+       bitmap->allclean = 0;
        return 0;
 }
 
@@ -1189,6 +1312,9 @@ void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long secto
                PRINTK(KERN_DEBUG "dec write-behind count %d/%d\n",
                  atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
        }
+       if (bitmap->mddev->degraded)
+               /* Never clear bits or update events_cleared when degraded */
+               success = 0;
 
        while (sectors) {
                int blocks;
@@ -1202,9 +1328,18 @@ void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long secto
                        return;
                }
 
+               if (success &&
+                   bitmap->events_cleared < bitmap->mddev->events) {
+                       bitmap->events_cleared = bitmap->mddev->events;
+                       bitmap->need_sync = 1;
+               }
+
                if (!success && ! (*bmc & NEEDED_MASK))
                        *bmc |= NEEDED_MASK;
 
+               if ((*bmc & COUNTER_MAX) == COUNTER_MAX)
+                       wake_up(&bitmap->overflow_wait);
+
                (*bmc)--;
                if (*bmc <= 2) {
                        set_page_attr(bitmap,
@@ -1219,8 +1354,8 @@ void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long secto
        }
 }
 
-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, int *blocks,
+                              int degraded)
 {
        bitmap_counter_t *bmc;
        int rv;
@@ -1244,6 +1379,30 @@ int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
                }
        }
        spin_unlock_irq(&bitmap->lock);
+       bitmap->allclean = 0;
+       return rv;
+}
+
+int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *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;
+       int blocks1;
+
+       *blocks = 0;
+       while (*blocks < (PAGE_SIZE>>9)) {
+               rv |= __bitmap_start_sync(bitmap, offset,
+                                         &blocks1, degraded);
+               offset += blocks1;
+               *blocks += blocks1;
+       }
        return rv;
 }
 
@@ -1280,6 +1439,7 @@ void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int ab
        }
  unlock:
        spin_unlock_irqrestore(&bitmap->lock, flags);
+       bitmap->allclean = 0;
 }
 
 void bitmap_close_sync(struct bitmap *bitmap)
@@ -1290,14 +1450,41 @@ void bitmap_close_sync(struct bitmap *bitmap)
         */
        sector_t sector = 0;
        int blocks;
-       if (!bitmap) return;
+       if (!bitmap)
+               return;
        while (sector < bitmap->mddev->resync_max_sectors) {
                bitmap_end_sync(bitmap, sector, &blocks, 0);
-/*
-               if (sector < 500) printk("bitmap_close_sync: sec %llu blks %d\n",
-                                        (unsigned long long)sector, blocks);
-*/             sector += blocks;
+               sector += blocks;
+       }
+}
+
+void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector)
+{
+       sector_t s = 0;
+       int blocks;
+
+       if (!bitmap)
+               return;
+       if (sector == 0) {
+               bitmap->last_end_sync = jiffies;
+               return;
+       }
+       if (time_before(jiffies, (bitmap->last_end_sync
+                                 + bitmap->daemon_sleep * HZ)))
+               return;
+       wait_event(bitmap->mddev->recovery_wait,
+                  atomic_read(&bitmap->mddev->recovery_active) == 0);
+
+       bitmap->mddev->curr_resync_completed = bitmap->mddev->curr_resync;
+       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) {
+               bitmap_end_sync(bitmap, s, &blocks, 0);
+               s += blocks;
        }
+       bitmap->last_end_sync = jiffies;
+       sysfs_notify(&bitmap->mddev->kobj, NULL, "sync_completed");
 }
 
 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
@@ -1323,7 +1510,19 @@ static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int n
                set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
        }
        spin_unlock_irq(&bitmap->lock);
+       bitmap->allclean = 0;
+}
 
+/* dirty the memory and file bits for bitmap chunks "s" to "e" */
+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 = (sector_t)chunk << CHUNK_BLOCK_SHIFT(bitmap);
+               bitmap_set_memory_bits(bitmap, sec, 1);
+               bitmap_file_set_bit(bitmap, sec);
+       }
 }
 
 /*
@@ -1396,14 +1595,14 @@ void bitmap_destroy(mddev_t *mddev)
 int bitmap_create(mddev_t *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;
        int err;
        sector_t start;
 
-       BUG_ON(sizeof(bitmap_super_t) != 256);
+       BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
 
        if (!file && !mddev->bitmap_offset) /* bitmap disabled, nothing to do */
                return 0;
@@ -1415,26 +1614,32 @@ int bitmap_create(mddev_t *mddev)
                return -ENOMEM;
 
        spin_lock_init(&bitmap->lock);
+       atomic_set(&bitmap->pending_writes, 0);
+       init_waitqueue_head(&bitmap->write_wait);
+       init_waitqueue_head(&bitmap->overflow_wait);
+
        bitmap->mddev = mddev;
 
        bitmap->file = file;
        bitmap->offset = mddev->bitmap_offset;
-       if (file) get_file(file);
-
-       /* Ensure we read fresh data */
-       invalidate_inode_pages(file->f_dentry->d_inode->i_mapping);
-
+       if (file) {
+               get_file(file);
+               /* As future accesses to this file will use bmap,
+                * and bypass the page cache, we must sync the file
+                * first.
+                */
+               vfs_fsync(file, file->f_dentry, 1);
+       }
        /* read superblock from bitmap file (this sets bitmap->chunksize) */
        err = bitmap_read_sb(bitmap);
        if (err)
                goto error;
 
-       bitmap->chunkshift = find_first_bit(&bitmap->chunksize,
-                                       sizeof(bitmap->chunksize));
+       bitmap->chunkshift = ffz(~bitmap->chunksize);
 
        /* now that chunksize and chunkshift are set, we can use these macros */
-       chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) /
-                       CHUNK_BLOCK_RATIO(bitmap);
+       chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) >>
+                       CHUNK_BLOCK_SHIFT(bitmap);
        pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
 
        BUG_ON(!pages);
@@ -1446,9 +1651,6 @@ int bitmap_create(mddev_t *mddev)
 
        bitmap->syncchunk = ~0UL;
 
-       atomic_set(&bitmap->pending_writes, 0);
-       init_waitqueue_head(&bitmap->write_wait);
-
 #ifdef INJECT_FATAL_FAULT_1
        bitmap->bp = NULL;
 #else
@@ -1477,7 +1679,9 @@ int bitmap_create(mddev_t *mddev)
 
        mddev->thread->timeout = bitmap->daemon_sleep * HZ;
 
-       return bitmap_update_sb(bitmap);
+       bitmap_update_sb(bitmap);
+
+       return (bitmap->flags & BITMAP_WRITE_ERROR) ? -EIO : 0;
 
  error:
        bitmap_free(bitmap);
@@ -1491,3 +1695,4 @@ EXPORT_SYMBOL(bitmap_start_sync);
 EXPORT_SYMBOL(bitmap_end_sync);
 EXPORT_SYMBOL(bitmap_unplug);
 EXPORT_SYMBOL(bitmap_close_sync);
+EXPORT_SYMBOL(bitmap_cond_end_sync);