Merge branch 'for-linus' of git://neil.brown.name/md

* 'for-linus' of git://neil.brown.name/md: (27 commits)
  md: add 'recovery_start' per-device sysfs attribute
  md: rcu_read_lock() walk of mddev->disks in md_do_sync()
  md: integrate spares into array at earliest opportunity.
  md: move compat_ioctl handling into md.c
  md: revise Kconfig help for MD_MULTIPATH
  md: add MODULE_DESCRIPTION for all md related modules.
  raid: improve MD/raid10 handling of correctable read errors.
  md/raid10: print more useful messages on device failure.
  md/bitmap: update dirty flag when bitmap bits are explicitly set.
  md: Support write-intent bitmaps with externally managed metadata.
  md/bitmap: move setting of daemon_lastrun out of bitmap_read_sb
  md: support updating bitmap parameters via sysfs.
  md: factor out parsing of fixed-point numbers
  md: support bitmap offset appropriate for external-metadata arrays.
  md: remove needless setting of thread->timeout in raid10_quiesce
  md: change daemon_sleep to be in 'jiffies' rather than 'seconds'.
  md: move offset, daemon_sleep and chunksize out of bitmap structure
  md: collect bitmap-specific fields into one structure.
  md/raid1: add takeover support for raid5->raid1
  md: add honouring of suspend_{lo,hi} to raid1.
  ...

14 files changed, 1059 insertions, 293 deletions

diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index 2158377a135..acb3a4e404f 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -185,11 +185,10 @@ config MD_MULTIPATH
 	tristate "Multipath I/O support"
 	depends on BLK_DEV_MD
 	help
-	  Multipath-IO is the ability of certain devices to address the same
-	  physical disk over multiple 'IO paths'. The code ensures that such
-	  paths can be defined and handled at runtime, and ensures that a
-	  transparent failover to the backup path(s) happens if a IO errors
-	  arrives on the primary path.
+	  MD_MULTIPATH provides a simple multi-path personality for use
+	  the MD framework.  It is not under active development.  New
+	  projects should consider using DM_MULTIPATH which has more
+	  features and more testing.
 
 	  If unsure, say N.
 
diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 60e2b322db1..26ac8aad0b1 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -212,7 +212,7 @@ 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(mddev_t *mddev, loff_t offset,
 				 struct page *page,
 				 unsigned long index, int size)
 {
@@ -287,27 +287,36 @@ static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
 
 	while ((rdev = next_active_rdev(rdev, mddev)) != NULL) {
 			int size = PAGE_SIZE;
+			loff_t offset = mddev->bitmap_info.offset;
 			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) {
+			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 (bitmap->offset
+				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 + bitmap->offset)
+				    > 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
-				    + bitmap->offset
+				    + offset
 				    + page->index*(PAGE_SIZE/512) + size/512
 				    > rdev->data_offset)
 					/* bitmap runs in to data */
@@ -316,7 +325,7 @@ static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
 				/* DATA METADATA BITMAP - no problems */
 			}
 			md_super_write(mddev, rdev,
-				       rdev->sb_start + bitmap->offset
+				       rdev->sb_start + offset
 				       + page->index * (PAGE_SIZE/512),
 				       size,
 				       page);
@@ -488,6 +497,8 @@ 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);
@@ -501,6 +512,9 @@ void bitmap_update_sb(struct bitmap *bitmap)
 		bitmap->events_cleared = bitmap->mddev->events;
 		sb->events_cleared = cpu_to_le64(bitmap->events_cleared);
 	}
+	/* 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);
 }
@@ -550,7 +564,8 @@ 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));
 	}
@@ -563,7 +578,7 @@ static int bitmap_read_sb(struct bitmap *bitmap)
 	sb = (bitmap_super_t *)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 */
@@ -576,7 +591,7 @@ static int bitmap_read_sb(struct bitmap *bitmap)
 		reason = "bitmap chunksize too small";
 	else if ((1 << ffz(~chunksize)) != 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)";
@@ -610,10 +625,9 @@ 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;
@@ -664,16 +678,26 @@ 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);
 }
 
 /*
@@ -686,8 +710,9 @@ 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)];
+	if (file_page_index(bitmap, chunk) >= bitmap->file_pages) return NULL;
+	return bitmap->filemap[file_page_index(bitmap, chunk)
+			       - file_page_index(bitmap, 0)];
 }
 
 
@@ -710,7 +735,7 @@ 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);
@@ -821,7 +846,7 @@ 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);
+	bit = file_page_offset(bitmap, chunk);
 
  	/* set the bit */
 	kaddr = kmap_atomic(page, KM_USER0);
@@ -907,7 +932,7 @@ 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;
@@ -919,14 +944,17 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
 			"recovery\n", bmname(bitmap));
 
 	bytes = (chunks + 7) / 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 = (bytes + PAGE_SIZE - 1) / 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;
 	}
 
@@ -947,17 +975,16 @@ 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)
@@ -967,14 +994,15 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
 				offset = sizeof(bitmap_super_t);
 				if (!file)
 					read_sb_page(bitmap->mddev,
-						     bitmap->offset,
+						     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;
@@ -1078,23 +1106,32 @@ static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
  *			out to disk
  */
 
-void bitmap_daemon_work(struct bitmap *bitmap)
+void bitmap_daemon_work(mddev_t *mddev)
 {
+	struct bitmap *bitmap;
 	unsigned long j;
 	unsigned long flags;
 	struct page *page = NULL, *lastpage = NULL;
 	int 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;
 
@@ -1142,7 +1179,8 @@ 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);
@@ -1152,7 +1190,8 @@ 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);
+			if (!bitmap->need_sync)
+				clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
 		}
 		bmc = bitmap_get_counter(bitmap,
 					 (sector_t)j << CHUNK_BLOCK_SHIFT(bitmap),
@@ -1167,7 +1206,7 @@ void bitmap_daemon_work(struct bitmap *bitmap)
 			if (*bmc == 2) {
 				*bmc=1; /* maybe clear the bit next time */
 				set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
-			} else if (*bmc == 1) {
+			} else if (*bmc == 1 && !bitmap->need_sync) {
 				/* we can clear the bit */
 				*bmc = 0;
 				bitmap_count_page(bitmap,
@@ -1177,9 +1216,11 @@ void bitmap_daemon_work(struct bitmap *bitmap)
 				/* 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);
+					ext2_clear_bit(file_page_offset(bitmap, j),
+						       paddr);
 				kunmap_atomic(paddr, KM_USER0);
 			}
 		} else
@@ -1202,7 +1243,9 @@ void bitmap_daemon_work(struct bitmap *bitmap)
 
  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,
@@ -1332,6 +1375,7 @@ void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long secto
 		    bitmap->events_cleared < bitmap->mddev->events) {
 			bitmap->events_cleared = bitmap->mddev->events;
 			bitmap->need_sync = 1;
+			sysfs_notify_dirent(bitmap->sysfs_can_clear);
 		}
 
 		if (!success && ! (*bmc & NEEDED_MASK))
@@ -1470,7 +1514,7 @@ 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);
@@ -1522,6 +1566,12 @@ void bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
 		sector_t sec = (sector_t)chunk << CHUNK_BLOCK_SHIFT(bitmap);
 		bitmap_set_memory_bits(bitmap, sec, 1);
 		bitmap_file_set_bit(bitmap, sec);
+		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;
 	}
 }
 
@@ -1531,7 +1581,7 @@ void bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
 void bitmap_flush(mddev_t *mddev)
 {
 	struct bitmap *bitmap = mddev->bitmap;
-	int sleep;
+	long sleep;
 
 	if (!bitmap) /* there was no bitmap */
 		return;
@@ -1539,12 +1589,13 @@ 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);
 }
 
@@ -1574,6 +1625,7 @@ static void bitmap_free(struct bitmap *bitmap)
 	kfree(bp);
 	kfree(bitmap);
 }
+
 void bitmap_destroy(mddev_t *mddev)
 {
 	struct bitmap *bitmap = mddev->bitmap;
@@ -1581,10 +1633,15 @@ void bitmap_destroy(mddev_t *mddev)
 	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);
 }
 
@@ -1598,16 +1655,17 @@ int bitmap_create(mddev_t *mddev)
 	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;
 
 	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)
@@ -1620,8 +1678,14 @@ int bitmap_create(mddev_t *mddev)
 
 	bitmap->mddev = mddev;
 
+	bm = sysfs_get_dirent(mddev->kobj.sd, "bitmap");
+	if (bm) {
+		bitmap->sysfs_can_clear = sysfs_get_dirent(bm, "can_clear");
+		sysfs_put(bm);
+	} else
+		bitmap->sysfs_can_clear = NULL;
+
 	bitmap->file = file;
-	bitmap->offset = mddev->bitmap_offset;
 	if (file) {
 		get_file(file);
 		/* As future accesses to this file will use bmap,
@@ -1630,12 +1694,22 @@ int bitmap_create(mddev_t *mddev)
 		 */
 		vfs_fsync(file, file->f_dentry, 1);
 	}
-	/* read superblock from bitmap file (this sets bitmap->chunksize) */
-	err = bitmap_read_sb(bitmap);
+	/* read superblock from bitmap file (this sets mddev->bitmap_info.chunksize) */
+	if (!mddev->bitmap_info.external)
+		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;
+	}
 	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) >>
@@ -1677,7 +1751,8 @@ int bitmap_create(mddev_t *mddev)
 
 	mddev->bitmap = bitmap;
 
-	mddev->thread->timeout = bitmap->daemon_sleep * HZ;
+	mddev->thread->timeout = mddev->bitmap_info.daemon_sleep;
+	md_wakeup_thread(mddev->thread);
 
 	bitmap_update_sb(bitmap);
 
@@ -1688,6 +1763,264 @@ int bitmap_create(mddev_t *mddev)
 	return err;
 }
 
+static ssize_t
+location_show(mddev_t *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;
+}
+
+static ssize_t
+location_store(mddev_t *mddev, const char *buf, size_t len)
+{
+
+	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) {
+					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;
+}
+
+static struct md_sysfs_entry bitmap_location =
+__ATTR(location, S_IRUGO|S_IWUSR, location_show, location_store);
+
+static ssize_t
+timeout_show(mddev_t *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(mddev_t *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(mddev_t *mddev, char *page)
+{
+	return sprintf(page, "%lu\n", mddev->bitmap_info.max_write_behind);
+}
+
+static ssize_t
+backlog_store(mddev_t *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(mddev_t *mddev, char *page)
+{
+	return sprintf(page, "%lu\n", mddev->bitmap_info.chunksize);
+}
+
+static ssize_t
+chunksize_store(mddev_t *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(mddev_t *mddev, char *page)
+{
+	return sprintf(page, "%s\n", (mddev->bitmap_info.external
+				      ? "external" : "internal"));
+}
+
+static ssize_t metadata_store(mddev_t *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(mddev_t *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(mddev_t *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 struct attribute *md_bitmap_attrs[] = {
+	&bitmap_location.attr,
+	&bitmap_timeout.attr,
+	&bitmap_backlog.attr,
+	&bitmap_chunksize.attr,
+	&bitmap_metadata.attr,
+	&bitmap_can_clear.attr,
+	NULL
+};
+struct attribute_group md_bitmap_group = {
+	.name = "bitmap",
+	.attrs = md_bitmap_attrs,
+};
+
+
 /* the bitmap API -- for raid personalities */
 EXPORT_SYMBOL(bitmap_startwrite);
 EXPORT_SYMBOL(bitmap_endwrite);
diff --git a/drivers/md/bitmap.h b/drivers/md/bitmap.h
index e98900671ca..cb821d76d1b 100644
--- a/drivers/md/bitmap.h
+++ b/drivers/md/bitmap.h
@@ -106,7 +106,7 @@ typedef __u16 bitmap_counter_t;
 #define BITMAP_BLOCK_SHIFT 9
 
 /* how many blocks per chunk? (this is variable) */
-#define CHUNK_BLOCK_RATIO(bitmap) ((bitmap)->chunksize >> BITMAP_BLOCK_SHIFT)
+#define CHUNK_BLOCK_RATIO(bitmap) ((bitmap)->mddev->bitmap_info.chunksize >> BITMAP_BLOCK_SHIFT)
 #define CHUNK_BLOCK_SHIFT(bitmap) ((bitmap)->chunkshift - BITMAP_BLOCK_SHIFT)
 #define CHUNK_BLOCK_MASK(bitmap) (CHUNK_BLOCK_RATIO(bitmap) - 1)
 
@@ -118,16 +118,6 @@ typedef __u16 bitmap_counter_t;
 			(CHUNK_BLOCK_SHIFT(bitmap) + PAGE_COUNTER_SHIFT - 1)
 #define PAGEPTR_BLOCK_MASK(bitmap) (PAGEPTR_BLOCK_RATIO(bitmap) - 1)
 
-/*
- * 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.
- */
-
-/* map chunks (bits) to file pages - offset by the size of the superblock */
-#define CHUNK_BIT_OFFSET(chunk) ((chunk) + (sizeof(bitmap_super_t) << 3))
-
 #endif
 
 /*
@@ -209,7 +199,6 @@ struct bitmap {
 	int counter_bits; /* how many bits per block counter */
 
 	/* bitmap chunksize -- how much data does each bit represent? */
-	unsigned long chunksize;
 	unsigned long chunkshift; /* chunksize = 2^chunkshift (for bitops) */
 	unsigned long chunks; /* total number of data chunks for the array */
 
@@ -226,7 +215,6 @@ struct bitmap {
 	/* bitmap spinlock */
 	spinlock_t lock;
 
-	long offset; /* offset from superblock if file is NULL */
 	struct file *file; /* backing disk file */
 	struct page *sb_page; /* cached copy of the bitmap file superblock */
 	struct page **filemap; /* list of cache pages for the file */
@@ -238,7 +226,6 @@ struct bitmap {
 
 	int allclean;
 
-	unsigned long max_write_behind; /* write-behind mode */
 	atomic_t behind_writes;
 
 	/*
@@ -246,7 +233,6 @@ struct bitmap {
 	 * file, cleaning up bits and flushing out pages to disk as necessary
 	 */
 	unsigned long daemon_lastrun; /* jiffies of last run */
-	unsigned long daemon_sleep; /* how many seconds between updates? */
 	unsigned long last_end_sync; /* when we lasted called end_sync to
 				      * update bitmap with resync progress */
 
@@ -254,6 +240,7 @@ struct bitmap {
 	wait_queue_head_t write_wait;
 	wait_queue_head_t overflow_wait;
 
+	struct sysfs_dirent *sysfs_can_clear;
 };
 
 /* the bitmap API */
@@ -282,7 +269,7 @@ void bitmap_close_sync(struct bitmap *bitmap);
 void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector);
 
 void bitmap_unplug(struct bitmap *bitmap);
-void bitmap_daemon_work(struct bitmap *bitmap);
+void bitmap_daemon_work(mddev_t *mddev);
 #endif
 
 #endif
diff --git a/drivers/md/faulty.c b/drivers/md/faulty.c
index 87d88dbb667..713acd02ab3 100644
--- a/drivers/md/faulty.c
+++ b/drivers/md/faulty.c
@@ -360,6 +360,7 @@ static void raid_exit(void)
 module_init(raid_init);
 module_exit(raid_exit);
 MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Fault injection personality for MD");
 MODULE_ALIAS("md-personality-10"); /* faulty */
 MODULE_ALIAS("md-faulty");
 MODULE_ALIAS("md-level--5");
diff --git a/drivers/md/linear.c b/drivers/md/linear.c
index 1ceceb334d5..00435bd2069 100644
--- a/drivers/md/linear.c
+++ b/drivers/md/linear.c
@@ -292,7 +292,7 @@ static int linear_make_request (struct request_queue *q, struct bio *bio)
 	int cpu;
 
 	if (unlikely(bio_rw_flagged(bio, BIO_RW_BARRIER))) {
-		bio_endio(bio, -EOPNOTSUPP);
+		md_barrier_request(mddev, bio);
 		return 0;
 	}
 
@@ -383,6 +383,7 @@ static void linear_exit (void)
 module_init(linear_init);
 module_exit(linear_exit);
 MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Linear device concatenation personality for MD");
 MODULE_ALIAS("md-personality-1"); /* LINEAR - deprecated*/
 MODULE_ALIAS("md-linear");
 MODULE_ALIAS("md-level--1");
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 5f154ef1e4b..e1f3c1715cc 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -44,6 +44,7 @@
 #include <linux/random.h>
 #include <linux/reboot.h>
 #include <linux/file.h>
+#include <linux/compat.h>
 #include <linux/delay.h>
 #include <linux/raid/md_p.h>
 #include <linux/raid/md_u.h>
@@ -68,6 +69,12 @@ static DECLARE_WAIT_QUEUE_HEAD(resync_wait);
 #define MD_BUG(x...) { printk("md: bug in file %s, line %d\n", __FILE__, __LINE__); md_print_devices(); }
 
 /*
+ * Default number of read corrections we'll attempt on an rdev
+ * before ejecting it from the array. We divide the read error
+ * count by 2 for every hour elapsed between read errors.
+ */
+#define MD_DEFAULT_MAX_CORRECTED_READ_ERRORS 20
+/*
  * Current RAID-1,4,5 parallel reconstruction 'guaranteed speed limit'
  * is 1000 KB/sec, so the extra system load does not show up that much.
  * Increase it if you want to have more _guaranteed_ speed. Note that
@@ -213,12 +220,12 @@ static int md_make_request(struct request_queue *q, struct bio *bio)
 		return 0;
 	}
 	rcu_read_lock();
-	if (mddev->suspended) {
+	if (mddev->suspended || mddev->barrier) {
 		DEFINE_WAIT(__wait);
 		for (;;) {
 			prepare_to_wait(&mddev->sb_wait, &__wait,
 					TASK_UNINTERRUPTIBLE);
-			if (!mddev->suspended)
+			if (!mddev->suspended && !mddev->barrier)
 				break;
 			rcu_read_unlock();
 			schedule();
@@ -260,10 +267,110 @@ static void mddev_resume(mddev_t *mddev)
 
 int mddev_congested(mddev_t *mddev, int bits)
 {
+	if (mddev->barrier)
+		return 1;
 	return mddev->suspended;
 }
 EXPORT_SYMBOL(mddev_congested);
 
+/*
+ * Generic barrier handling for md
+ */
+
+#define POST_REQUEST_BARRIER ((void*)1)
+
+static void md_end_barrier(struct bio *bio, int err)
+{
+	mdk_rdev_t *rdev = bio->bi_private;
+	mddev_t *mddev = rdev->mddev;
+	if (err == -EOPNOTSUPP && mddev->barrier != POST_REQUEST_BARRIER)
+		set_bit(BIO_EOPNOTSUPP, &mddev->barrier->bi_flags);
+
+	rdev_dec_pending(rdev, mddev);
+
+	if (atomic_dec_and_test(&mddev->flush_pending)) {
+		if (mddev->barrier == POST_REQUEST_BARRIER) {
+			/* This was a post-request barrier */
+			mddev->barrier = NULL;
+			wake_up(&mddev->sb_wait);
+		} else
+			/* The pre-request barrier has finished */
+			schedule_work(&mddev->barrier_work);
+	}
+	bio_put(bio);
+}
+
+static void submit_barriers(mddev_t *mddev)
+{
+	mdk_rdev_t *rdev;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(rdev, &mddev->disks, same_set)
+		if (rdev->raid_disk >= 0 &&
+		    !test_bit(Faulty, &rdev->flags)) {
+			/* Take two references, one is dropped
+			 * when request finishes, one after
+			 * we reclaim rcu_read_lock
+			 */
+			struct bio *bi;
+			atomic_inc(&rdev->nr_pending);
+			atomic_inc(&rdev->nr_pending);
+			rcu_read_unlock();
+			bi = bio_alloc(GFP_KERNEL, 0);
+			bi->bi_end_io = md_end_barrier;
+			bi->bi_private = rdev;
+			bi->bi_bdev = rdev->bdev;
+			atomic_inc(&mddev->flush_pending);
+			submit_bio(WRITE_BARRIER, bi);
+			rcu_read_lock();
+			rdev_dec_pending(rdev, mddev);
+		}
+	rcu_read_unlock();
+}
+
+static void md_submit_barrier(struct work_struct *ws)
+{
+	mddev_t *mddev = container_of(ws, mddev_t, barrier_work);
+	struct bio *bio = mddev->barrier;
+
+	atomic_set(&mddev->flush_pending, 1);
+
+	if (test_bit(BIO_EOPNOTSUPP, &bio->bi_flags))
+		bio_endio(bio, -EOPNOTSUPP);
+	else if (bio->bi_size == 0)
+		/* an empty barrier - all done */
+		bio_endio(bio, 0);
+	else {
+		bio->bi_rw &= ~(1<<BIO_RW_BARRIER);
+		if (mddev->pers->make_request(mddev->queue, bio))
+			generic_make_request(bio);
+		mddev->barrier = POST_REQUEST_BARRIER;
+		submit_barriers(mddev);
+	}
+	if (atomic_dec_and_test(&mddev->flush_pending)) {
+		mddev->barrier = NULL;
+		wake_up(&mddev->sb_wait);
+	}
+}
+
+void md_barrier_request(mddev_t *mddev, struct bio *bio)
+{
+	spin_lock_irq(&mddev->write_lock);
+	wait_event_lock_irq(mddev->sb_wait,
+			    !mddev->barrier,
+			    mddev->write_lock, /*nothing*/);
+	mddev->barrier = bio;
+	spin_unlock_irq(&mddev->write_lock);
+
+	atomic_set(&mddev->flush_pending, 1);
+	INIT_WORK(&mddev->barrier_work, md_submit_barrier);
+
+	submit_barriers(mddev);
+
+	if (atomic_dec_and_test(&mddev->flush_pending))
+		schedule_work(&mddev->barrier_work);
+}
+EXPORT_SYMBOL(md_barrier_request);
 
 static inline mddev_t *mddev_get(mddev_t *mddev)
 {
@@ -363,6 +470,7 @@ static mddev_t * mddev_find(dev_t unit)
 
 	mutex_init(&new->open_mutex);
 	mutex_init(&new->reconfig_mutex);
+	mutex_init(&new->bitmap_info.mutex);
 	INIT_LIST_HEAD(&new->disks);
 	INIT_LIST_HEAD(&new->all_mddevs);
 	init_timer(&new->safemode_timer);
@@ -370,6 +478,7 @@ static mddev_t * mddev_find(dev_t unit)
 	atomic_set(&new->openers, 0);
 	atomic_set(&new->active_io, 0);
 	spin_lock_init(&new->write_lock);
+	atomic_set(&new->flush_pending, 0);
 	init_waitqueue_head(&new->sb_wait);
 	init_waitqueue_head(&new->recovery_wait);
 	new->reshape_position = MaxSector;
@@ -748,7 +857,7 @@ struct super_type  {
  */
 int md_check_no_bitmap(mddev_t *mddev)
 {
-	if (!mddev->bitmap_file && !mddev->bitmap_offset)
+	if (!mddev->bitmap_info.file && !mddev->bitmap_info.offset)
 		return 0;
 	printk(KERN_ERR "%s: bitmaps are not supported for %s\n",
 		mdname(mddev), mddev->pers->name);
@@ -876,8 +985,8 @@ static int super_90_validate(mddev_t *mddev, mdk_rdev_t *rdev)
 		mddev->raid_disks = sb->raid_disks;
 		mddev->dev_sectors = sb->size * 2;
 		mddev->events = ev1;
-		mddev->bitmap_offset = 0;
-		mddev->default_bitmap_offset = MD_SB_BYTES >> 9;
+		mddev->bitmap_info.offset = 0;
+		mddev->bitmap_info.default_offset = MD_SB_BYTES >> 9;
 
 		if (mddev->minor_version >= 91) {
 			mddev->reshape_position = sb->reshape_position;
@@ -911,8 +1020,9 @@ static int super_90_validate(mddev_t *mddev, mdk_rdev_t *rdev)
 		mddev->max_disks = MD_SB_DISKS;
 
 		if (sb->state & (1<<MD_SB_BITMAP_PRESENT) &&
-		    mddev->bitmap_file == NULL)
-			mddev->bitmap_offset = mddev->default_bitmap_offset;
+		    mddev->bitmap_info.file == NULL)
+			mddev->bitmap_info.offset =
+				mddev->bitmap_info.default_offset;
 
 	} else if (mddev->pers == NULL) {
 		/* Insist on good event counter while assembling */
@@ -1029,7 +1139,7 @@ static void super_90_sync(mddev_t *mddev, mdk_rdev_t *rdev)
 	sb->layout = mddev->layout;
 	sb->chunk_size = mddev->chunk_sectors << 9;
 
-	if (mddev->bitmap && mddev->bitmap_file == NULL)
+	if (mddev->bitmap && mddev->bitmap_info.file == NULL)
 		sb->state |= (1<<MD_SB_BITMAP_PRESENT);
 
 	sb->disks[0].state = (1<<MD_DISK_REMOVED);
@@ -1107,7 +1217,7 @@ super_90_rdev_size_change(mdk_rdev_t *rdev, sector_t num_sectors)
 {
 	if (num_sectors && num_sectors < rdev->mddev->dev_sectors)
 		return 0; /* component must fit device */
-	if (rdev->mddev->bitmap_offset)
+	if (rdev->mddev->bitmap_info.offset)
 		return 0; /* can't move bitmap */
 	rdev->sb_start = calc_dev_sboffset(rdev->bdev);
 	if (!num_sectors || num_sectors > rdev->sb_start)
@@ -1286,8 +1396,8 @@ static int super_1_validate(mddev_t *mddev, mdk_rdev_t *rdev)
 		mddev->raid_disks = le32_to_cpu(sb->raid_disks);
 		mddev->dev_sectors = le64_to_cpu(sb->size);
 		mddev->events = ev1;
-		mddev->bitmap_offset = 0;
-		mddev->default_bitmap_offset = 1024 >> 9;
+		mddev->bitmap_info.offset = 0;
+		mddev->bitmap_info.default_offset = 1024 >> 9;
 		
 		mddev->recovery_cp = le64_to_cpu(sb->resync_offset);
 		memcpy(mddev->uuid, sb->set_uuid, 16);
@@ -1295,8 +1405,9 @@ static int super_1_validate(mddev_t *mddev, mdk_rdev_t *rdev)
 		mddev->max_disks =  (4096-256)/2;
 
 		if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_BITMAP_OFFSET) &&
-		    mddev->bitmap_file == NULL )
-			mddev->bitmap_offset = (__s32)le32_to_cpu(sb->bitmap_offset);
+		    mddev->bitmap_info.file == NULL )
+			mddev->bitmap_info.offset =
+				(__s32)le32_to_cpu(sb->bitmap_offset);
 
 		if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_RESHAPE_ACTIVE)) {
 			mddev->reshape_position = le64_to_cpu(sb->reshape_position);
@@ -1390,19 +1501,17 @@ static void super_1_sync(mddev_t *mddev, mdk_rdev_t *rdev)
 	sb->level = cpu_to_le32(mddev->level);
 	sb->layout = cpu_to_le32(mddev->layout);
 
-	if (mddev->bitmap && mddev->bitmap_file == NULL) {
-		sb->bitmap_offset = cpu_to_le32((__u32)mddev->bitmap_offset);
+	if (mddev->bitmap && mddev->bitmap_info.file == NULL) {
+		sb->bitmap_offset = cpu_to_le32((__u32)mddev->bitmap_info.offset);
 		sb->feature_map = cpu_to_le32(MD_FEATURE_BITMAP_OFFSET);
 	}
 
 	if (rdev->raid_disk >= 0 &&
 	    !test_bit(In_sync, &rdev->flags)) {
-		if (rdev->recovery_offset > 0) {
-			sb->feature_map |=
-				cpu_to_le32(MD_FEATURE_RECOVERY_OFFSET);
-			sb->recovery_offset =
-				cpu_to_le64(rdev->recovery_offset);
-		}
+		sb->feature_map |=
+			cpu_to_le32(MD_FEATURE_RECOVERY_OFFSET);
+		sb->recovery_offset =
+			cpu_to_le64(rdev->recovery_offset);
 	}
 
 	if (mddev->reshape_position != MaxSector) {
@@ -1436,7 +1545,7 @@ static void super_1_sync(mddev_t *mddev, mdk_rdev_t *rdev)
 			sb->dev_roles[i] = cpu_to_le16(0xfffe);
 		else if (test_bit(In_sync, &rdev2->flags))
 			sb->dev_roles[i] = cpu_to_le16(rdev2->raid_disk);
-		else if (rdev2->raid_disk >= 0 && rdev2->recovery_offset > 0)
+		else if (rdev2->raid_disk >= 0)
 			sb->dev_roles[i] = cpu_to_le16(rdev2->raid_disk);
 		else
 			sb->dev_roles[i] = cpu_to_le16(0xffff);
@@ -1458,7 +1567,7 @@ super_1_rdev_size_change(mdk_rdev_t *rdev, sector_t num_sectors)
 		max_sectors -= rdev->data_offset;
 		if (!num_sectors || num_sectors > max_sectors)
 			num_sectors = max_sectors;
-	} else if (rdev->mddev->bitmap_offset) {
+	} else if (rdev->mddev->bitmap_info.offset) {
 		/* minor version 0 with bitmap we can't move */
 		return 0;
 	} else {
@@ -2442,12 +2551,49 @@ rdev_size_store(mdk_rdev_t *rdev, const char *buf, size_t len)
 static struct rdev_sysfs_entry rdev_size =
 __ATTR(size, S_IRUGO|S_IWUSR, rdev_size_show, rdev_size_store);
 
+
+static ssize_t recovery_start_show(mdk_rdev_t *rdev, char *page)
+{
+	unsigned long long recovery_start = rdev->recovery_offset;
+
+	if (test_bit(In_sync, &rdev->flags) ||
+	    recovery_start == MaxSector)
+		return sprintf(page, "none\n");
+
+	return sprintf(page, "%llu\n", recovery_start);
+}
+
+static ssize_t recovery_start_store(mdk_rdev_t *rdev, const char *buf, size_t len)
+{
+	unsigned long long recovery_start;
+
+	if (cmd_match(buf, "none"))
+		recovery_start = MaxSector;
+	else if (strict_strtoull(buf, 10, &recovery_start))
+		return -EINVAL;
+
+	if (rdev->mddev->pers &&
+	    rdev->raid_disk >= 0)
+		return -EBUSY;
+
+	rdev->recovery_offset = recovery_start;
+	if (recovery_start == MaxSector)
+		set_bit(In_sync, &rdev->flags);
+	else
+		clear_bit(In_sync, &rdev->flags);
+	return len;
+}
+
+static struct rdev_sysfs_entry rdev_recovery_start =
+__ATTR(recovery_start, S_IRUGO|S_IWUSR, recovery_start_show, recovery_start_store);
+
 static struct attribute *rdev_default_attrs[] = {
 	&rdev_state.attr,
 	&rdev_errors.attr,
 	&rdev_slot.attr,
 	&rdev_offset.attr,
 	&rdev_size.attr,
+	&rdev_recovery_start.attr,
 	NULL,
 };
 static ssize_t
@@ -2549,6 +2695,8 @@ static mdk_rdev_t *md_import_device(dev_t newdev, int super_format, int super_mi
 	rdev->flags = 0;
 	rdev->data_offset = 0;
 	rdev->sb_events = 0;
+	rdev->last_read_error.tv_sec  = 0;
+	rdev->last_read_error.tv_nsec = 0;
 	atomic_set(&rdev->nr_pending, 0);
 	atomic_set(&rdev->read_errors, 0);
 	atomic_set(&rdev->corrected_errors, 0);
@@ -2659,6 +2807,47 @@ static void analyze_sbs(mddev_t * mddev)
 	}
 }
 
+/* Read a fixed-point number.
+ * Numbers in sysfs attributes should be in "standard" units where
+ * possible, so time should be in seconds.
+ * However we internally use a a much smaller unit such as 
+ * milliseconds or jiffies.
+ * This function takes a decimal number with a possible fractional
+ * component, and produces an integer which is the result of
+ * multiplying that number by 10^'scale'.
+ * all without any floating-point arithmetic.
+ */
+int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale)
+{
+	unsigned long result = 0;
+	long decimals = -1;
+	while (isdigit(*cp) || (*cp == '.' && decimals < 0)) {
+		if (*cp == '.')
+			decimals = 0;
+		else if (decimals < scale) {
+			unsigned int value;
+			value = *cp - '0';
+			result = result * 10 + value;
+			if (decimals >= 0)
+				decimals++;
+		}
+		cp++;
+	}
+	if (*cp == '\n')
+		cp++;
+	if (*cp)
+		return -EINVAL;
+	if (decimals < 0)
+		decimals = 0;
+	while (decimals < scale) {
+		result *= 10;
+		decimals ++;
+	}
+	*res = result;
+	return 0;
+}
+
+
 static void md_safemode_timeout(unsigned long data);
 
 static ssize_t
@@ -2670,31 +2859,10 @@ safe_delay_show(mddev_t *mddev, char *page)
 static ssize_t
 safe_delay_store(mddev_t *mddev, const char *cbuf, size_t len)
 {
-	int scale=1;
-	int dot=0;
-	int i;
 	unsigned long msec;
-	char buf[30];
 
-	/* remove a period, and count digits after it */
-	if (len >= sizeof(buf))
-		return -EINVAL;
-	strlcpy(buf, cbuf, sizeof(buf));
-	for (i=0; i<len; i++) {
-		if (dot) {
-			if (isdigit(buf[i])) {
-				buf[i-1] = buf[i];
-				scale *= 10;
-			}
-			buf[i] = 0;
-		} else if (buf[i] == '.') {
-			dot=1;
-			buf[i] = 0;
-		}
-	}
-	if (strict_strtoul(buf, 10, &msec) < 0)
+	if (strict_strtoul_scaled(cbuf, &msec, 3) < 0)
 		return -EINVAL;
-	msec = (msec * 1000) / scale;
 	if (msec == 0)
 		mddev->safemode_delay = 0;
 	else {
@@ -2970,7 +3138,9 @@ resync_start_store(mddev_t *mddev, const char *buf, size_t len)
 
 	if (mddev->pers)
 		return -EBUSY;
-	if (!*buf || (*e && *e != '\n'))
+	if (cmd_match(buf, "none"))
+		n = MaxSector;
+	else if (!*buf || (*e && *e != '\n'))
 		return -EINVAL;
 
 	mddev->recovery_cp = n;
@@ -3166,6 +3336,29 @@ static struct md_sysfs_entry md_array_state =
 __ATTR(array_state, S_IRUGO|S_IWUSR, array_state_show, array_state_store);
 
 static ssize_t
+max_corrected_read_errors_show(mddev_t *mddev, char *page) {
+	return sprintf(page, "%d\n",
+		       atomic_read(&mddev->max_corr_read_errors));
+}
+
+static ssize_t
+max_corrected_read_errors_store(mddev_t *mddev, const char *buf, size_t len)
+{
+	char *e;
+	unsigned long n = simple_strtoul(buf, &e, 10);
+
+	if (*buf && (*e == 0 || *e == '\n')) {
+		atomic_set(&mddev->max_corr_read_errors, n);
+		return len;
+	}
+	return -EINVAL;
+}
+
+static struct md_sysfs_entry max_corr_read_errors =
+__ATTR(max_read_errors, S_IRUGO|S_IWUSR, max_corrected_read_errors_show,
+	max_corrected_read_errors_store);
+
+static ssize_t
 null_show(mddev_t *mddev, char *page)
 {
 	return -EINVAL;
@@ -3790,6 +3983,7 @@ static struct attribute *md_default_attrs[] = {
 	&md_array_state.attr,
 	&md_reshape_position.attr,
 	&md_array_size.attr,
+	&max_corr_read_errors.attr,
 	NULL,
 };
 
@@ -3894,6 +4088,7 @@ static void mddev_delayed_delete(struct work_struct *ws)
 		mddev->sysfs_action = NULL;
 		mddev->private = NULL;
 	}
+	sysfs_remove_group(&mddev->kobj, &md_bitmap_group);
 	kobject_del(&mddev->kobj);
 	kobject_put(&mddev->kobj);
 }
@@ -3985,6 +4180,8 @@ static int md_alloc(dev_t dev, char *name)
 		       disk->disk_name);
 		error = 0;
 	}
+	if (sysfs_create_group(&mddev->kobj, &md_bitmap_group))
+		printk(KERN_DEBUG "pointless warning\n");
  abort:
 	mutex_unlock(&disks_mutex);
 	if (!error) {
@@ -4206,6 +4403,8 @@ static int do_md_run(mddev_t * mddev)
 		mddev->ro = 0;
 
  	atomic_set(&mddev->writes_pending,0);
+	atomic_set(&mddev->max_corr_read_errors,
+		   MD_DEFAULT_MAX_CORRECTED_READ_ERRORS);
 	mddev->safemode = 0;
 	mddev->safemode_timer.function = md_safemode_timeout;
 	mddev->safemode_timer.data = (unsigned long) mddev;
@@ -4310,7 +4509,7 @@ static int deny_bitmap_write_access(struct file * file)
 	return 0;
 }
 
-static void restore_bitmap_write_access(struct file *file)
+void restore_bitmap_write_access(struct file *file)
 {
 	struct inode *inode = file->f_mapping->host;
 
@@ -4405,12 +4604,12 @@ out:
 		printk(KERN_INFO "md: %s stopped.\n", mdname(mddev));
 
 		bitmap_destroy(mddev);
-		if (mddev->bitmap_file) {
-			restore_bitmap_write_access(mddev->bitmap_file);
-			fput(mddev->bitmap_file);
-			mddev->bitmap_file = NULL;
+		if (mddev->bitmap_info.file) {
+			restore_bitmap_write_access(mddev->bitmap_info.file);
+			fput(mddev->bitmap_info.file);
+			mddev->bitmap_info.file = NULL;
 		}
-		mddev->bitmap_offset = 0;
+		mddev->bitmap_info.offset = 0;
 
 		/* make sure all md_delayed_delete calls have finished */
 		flush_scheduled_work();
@@ -4451,6 +4650,11 @@ out:
 		mddev->degraded = 0;
 		mddev->barriers_work = 0;
 		mddev->safemode = 0;
+		mddev->bitmap_info.offset = 0;
+		mddev->bitmap_info.default_offset = 0;
+		mddev->bitmap_info.chunksize = 0;
+		mddev->bitmap_info.daemon_sleep = 0;
+		mddev->bitmap_info.max_write_behind = 0;
 		kobject_uevent(&disk_to_dev(mddev->gendisk)->kobj, KOBJ_CHANGE);
 		if (mddev->hold_active == UNTIL_STOP)
 			mddev->hold_active = 0;
@@ -4636,7 +4840,7 @@ static int get_array_info(mddev_t * mddev, void __user * arg)
 	info.state         = 0;
 	if (mddev->in_sync)
 		info.state = (1<<MD_SB_CLEAN);
-	if (mddev->bitmap && mddev->bitmap_offset)
+	if (mddev->bitmap && mddev->bitmap_info.offset)
 		info.state = (1<<MD_SB_BITMAP_PRESENT);
 	info.active_disks  = insync;
 	info.working_disks = working;
@@ -4994,23 +5198,23 @@ static int set_bitmap_file(mddev_t *mddev, int fd)
 	if (fd >= 0) {
 		if (mddev->bitmap)
 			return -EEXIST; /* cannot add when bitmap is present */
-		mddev->bitmap_file = fget(fd);
+		mddev->bitmap_info.file = fget(fd);
 
-		if (mddev->bitmap_file == NULL) {
+		if (mddev->bitmap_info.file == NULL) {
 			printk(KERN_ERR "%s: error: failed to get bitmap file\n",
 			       mdname(mddev));
 			return -EBADF;
 		}
 
-		err = deny_bitmap_write_access(mddev->bitmap_file);
+		err = deny_bitmap_write_access(mddev->bitmap_info.file);
 		if (err) {
 			printk(KERN_ERR "%s: error: bitmap file is already in use\n",
 			       mdname(mddev));
-			fput(mddev->bitmap_file);
-			mddev->bitmap_file = NULL;
+			fput(mddev->bitmap_info.file);
+			mddev->bitmap_info.file = NULL;
 			return err;
 		}
-		mddev->bitmap_offset = 0; /* file overrides offset */
+		mddev->bitmap_info.offset = 0; /* file overrides offset */
 	} else if (mddev->bitmap == NULL)
 		return -ENOENT; /* cannot remove what isn't there */
 	err = 0;
@@ -5025,11 +5229,11 @@ static int set_bitmap_file(mddev_t *mddev, int fd)
 		mddev->pers->quiesce(mddev, 0);
 	}
 	if (fd < 0) {
-		if (mddev->bitmap_file) {
-			restore_bitmap_write_access(mddev->bitmap_file);
-			fput(mddev->bitmap_file);
+		if (mddev->bitmap_info.file) {
+			restore_bitmap_write_access(mddev->bitmap_info.file);
+			fput(mddev->bitmap_info.file);
 		}
-		mddev->bitmap_file = NULL;
+		mddev->bitmap_info.file = NULL;
 	}
 
 	return err;
@@ -5096,8 +5300,8 @@ static int set_array_info(mddev_t * mddev, mdu_array_info_t *info)
 		mddev->flags         = 0;
 	set_bit(MD_CHANGE_DEVS, &mddev->flags);
 
-	mddev->default_bitmap_offset = MD_SB_BYTES >> 9;
-	mddev->bitmap_offset = 0;
+	mddev->bitmap_info.default_offset = MD_SB_BYTES >> 9;
+	mddev->bitmap_info.offset = 0;
 
 	mddev->reshape_position = MaxSector;
 
@@ -5197,7 +5401,7 @@ static int update_array_info(mddev_t *mddev, mdu_array_info_t *info)
 	int state = 0;
 
 	/* calculate expected state,ignoring low bits */
-	if (mddev->bitmap && mddev->bitmap_offset)
+	if (mddev->bitmap && mddev->bitmap_info.offset)
 		state |= (1 << MD_SB_BITMAP_PRESENT);
 
 	if (mddev->major_version != info->major_version ||
@@ -5256,9 +5460,10 @@ static int update_array_info(mddev_t *mddev, mdu_array_info_t *info)
 			/* add the bitmap */
 			if (mddev->bitmap)
 				return -EEXIST;
-			if (mddev->default_bitmap_offset == 0)
+			if (mddev->bitmap_info.default_offset == 0)
 				return -EINVAL;
-			mddev->bitmap_offset = mddev->default_bitmap_offset;
+			mddev->bitmap_info.offset =
+				mddev->bitmap_info.default_offset;
 			mddev->pers->quiesce(mddev, 1);
 			rv = bitmap_create(mddev);
 			if (rv)
@@ -5273,7 +5478,7 @@ static int update_array_info(mddev_t *mddev, mdu_array_info_t *info)
 			mddev->pers->quiesce(mddev, 1);
 			bitmap_destroy(mddev);
 			mddev->pers->quiesce(mddev, 0);
-			mddev->bitmap_offset = 0;
+			mddev->bitmap_info.offset = 0;
 		}
 	}
 	md_update_sb(mddev, 1);
@@ -5524,6 +5729,25 @@ done:
 abort:
 	return err;
 }
+#ifdef CONFIG_COMPAT
+static int md_compat_ioctl(struct block_device *bdev, fmode_t mode,
+		    unsigned int cmd, unsigned long arg)
+{
+	switch (cmd) {
+	case HOT_REMOVE_DISK:
+	case HOT_ADD_DISK:
+	case SET_DISK_FAULTY:
+	case SET_BITMAP_FILE:
+		/* These take in integer arg, do not convert */
+		break;
+	default:
+		arg = (unsigned long)compat_ptr(arg);
+		break;
+	}
+
+	return md_ioctl(bdev, mode, cmd, arg);
+}
+#endif /* CONFIG_COMPAT */
 
 static int md_open(struct block_device *bdev, fmode_t mode)
 {
@@ -5589,6 +5813,9 @@ static const struct block_device_operations md_fops =
 	.open		= md_open,
 	.release	= md_release,
 	.ioctl		= md_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= md_compat_ioctl,
+#endif
 	.getgeo		= md_getgeo,
 	.media_changed	= md_media_changed,
 	.revalidate_disk= md_revalidate,
@@ -5982,14 +6209,14 @@ static int md_seq_show(struct seq_file *seq, void *v)
 			unsigned long chunk_kb;
 			unsigned long flags;
 			spin_lock_irqsave(&bitmap->lock, flags);
-			chunk_kb = bitmap->chunksize >> 10;
+			chunk_kb = mddev->bitmap_info.chunksize >> 10;
 			seq_printf(seq, "bitmap: %lu/%lu pages [%luKB], "
 				"%lu%s chunk",
 				bitmap->pages - bitmap->missing_pages,
 				bitmap->pages,
 				(bitmap->pages - bitmap->missing_pages)
 					<< (PAGE_SHIFT - 10),
-				chunk_kb ? chunk_kb : bitmap->chunksize,
+				chunk_kb ? chunk_kb : mddev->bitmap_info.chunksize,
 				chunk_kb ? "KB" : "B");
 			if (bitmap->file) {
 				seq_printf(seq, ", file: ");
@@ -6338,12 +6565,14 @@ void md_do_sync(mddev_t *mddev)
 		/* recovery follows the physical size of devices */
 		max_sectors = mddev->dev_sectors;
 		j = MaxSector;
-		list_for_each_entry(rdev, &mddev->disks, same_set)
+		rcu_read_lock();
+		list_for_each_entry_rcu(rdev, &mddev->disks, same_set)
 			if (rdev->raid_disk >= 0 &&
 			    !test_bit(Faulty, &rdev->flags) &&
 			    !test_bit(In_sync, &rdev->flags) &&
 			    rdev->recovery_offset < j)
 				j = rdev->recovery_offset;
+		rcu_read_unlock();
 	}
 
 	printk(KERN_INFO "md: %s of RAID array %s\n", desc, mdname(mddev));
@@ -6380,6 +6609,7 @@ void md_do_sync(mddev_t *mddev)
 		       desc, mdname(mddev));
 		mddev->curr_resync = j;
 	}
+	mddev->curr_resync_completed = mddev->curr_resync;
 
 	while (j < max_sectors) {
 		sector_t sectors;
@@ -6512,22 +6742,29 @@ void md_do_sync(mddev_t *mddev)
 		} else {
 			if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery))
 				mddev->curr_resync = MaxSector;
-			list_for_each_entry(rdev, &mddev->disks, same_set)
+			rcu_read_lock();
+			list_for_each_entry_rcu(rdev, &mddev->disks, same_set)
 				if (rdev->raid_disk >= 0 &&
 				    !test_bit(Faulty, &rdev->flags) &&
 				    !test_bit(In_sync, &rdev->flags) &&
 				    rdev->recovery_offset < mddev->curr_resync)
 					rdev->recovery_offset = mddev->curr_resync;
+			rcu_read_unlock();
 		}
 	}
 	set_bit(MD_CHANGE_DEVS, &mddev->flags);
 
  skip:
+	if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
+		/* We completed so min/max setting can be forgotten if used. */
+		if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
+			mddev->resync_min = 0;
+		mddev->resync_max = MaxSector;
+	} else if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
+		mddev->resync_min = mddev->curr_resync_completed;
 	mddev->curr_resync = 0;
-	mddev->curr_resync_completed = 0;
 	if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery))
-		/* We completed so max setting can be forgotten. */
-		mddev->resync_max = MaxSector;
+		mddev->curr_resync_completed = 0;
 	sysfs_notify(&mddev->kobj, NULL, "sync_completed");
 	wake_up(&resync_wait);
 	set_bit(MD_RECOVERY_DONE, &mddev->recovery);
@@ -6590,6 +6827,7 @@ static int remove_and_add_spares(mddev_t *mddev)
 						       nm, mdname(mddev));
 					spares++;
 					md_new_event(mddev);
+					set_bit(MD_CHANGE_DEVS, &mddev->flags);
 				} else
 					break;
 			}
@@ -6625,7 +6863,7 @@ void md_check_recovery(mddev_t *mddev)
 
 
 	if (mddev->bitmap)
-		bitmap_daemon_work(mddev->bitmap);
+		bitmap_daemon_work(mddev);
 
 	if (mddev->ro)
 		return;
@@ -6995,5 +7233,6 @@ EXPORT_SYMBOL(md_unregister_thread);
 EXPORT_SYMBOL(md_wakeup_thread);
 EXPORT_SYMBOL(md_check_recovery);
 MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("MD RAID framework");
 MODULE_ALIAS("md");
 MODULE_ALIAS_BLOCKDEV_MAJOR(MD_MAJOR);
diff --git a/drivers/md/md.h b/drivers/md/md.h
index f184b69ef33..8e4c75c00d4 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -97,6 +97,9 @@ struct mdk_rdev_s
 	atomic_t	read_errors;	/* number of consecutive read errors that
 					 * we have tried to ignore.
 					 */
+	struct timespec last_read_error;	/* monotonic time since our
+						 * last read error
+						 */
 	atomic_t	corrected_errors; /* number of corrected read errors,
 					   * for reporting to userspace and storing
 					   * in superblock.
@@ -280,17 +283,38 @@ struct mddev_s
 	unsigned int                    max_write_behind; /* 0 = sync */
 
 	struct bitmap                   *bitmap; /* the bitmap for the device */
-	struct file			*bitmap_file; /* the bitmap file */
-	long				bitmap_offset; /* offset from superblock of
-							* start of bitmap. May be
-							* negative, but not '0'
-							*/
-	long				default_bitmap_offset; /* this is the offset to use when
-								* hot-adding a bitmap.  It should
-								* eventually be settable by sysfs.
-								*/
-
+	struct {
+		struct file		*file; /* the bitmap file */
+		loff_t			offset; /* offset from superblock of
+						 * start of bitmap. May be
+						 * negative, but not '0'
+						 * For external metadata, offset
+						 * from start of device. 
+						 */
+		loff_t			default_offset; /* this is the offset to use when
+							 * hot-adding a bitmap.  It should
+							 * eventually be settable by sysfs.
+							 */
+		struct mutex		mutex;
+		unsigned long		chunksize;
+		unsigned long		daemon_sleep; /* how many seconds between updates? */
+		unsigned long		max_write_behind; /* write-behind mode */
+		int			external;
+	} bitmap_info;
+
+	atomic_t 			max_corr_read_errors; /* max read retries */
 	struct list_head		all_mddevs;
+
+	/* Generic barrier handling.
+	 * If there is a pending barrier request, all other
+	 * writes are blocked while the devices are flushed.
+	 * The last to finish a flush schedules a worker to
+	 * submit the barrier request (without the barrier flag),
+	 * then submit more flush requests.
+	 */
+	struct bio *barrier;
+	atomic_t flush_pending;
+	struct work_struct barrier_work;
 };
 
 
@@ -353,7 +377,7 @@ struct md_sysfs_entry {
 	ssize_t (*show)(mddev_t *, char *);
 	ssize_t (*store)(mddev_t *, const char *, size_t);
 };
-
+extern struct attribute_group md_bitmap_group;
 
 static inline char * mdname (mddev_t * mddev)
 {
@@ -431,6 +455,7 @@ extern void md_done_sync(mddev_t *mddev, int blocks, int ok);
 extern void md_error(mddev_t *mddev, mdk_rdev_t *rdev);
 
 extern int mddev_congested(mddev_t *mddev, int bits);
+extern void md_barrier_request(mddev_t *mddev, struct bio *bio);
 extern void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev,
 			   sector_t sector, int size, struct page *page);
 extern void md_super_wait(mddev_t *mddev);
@@ -443,6 +468,8 @@ extern void md_wait_for_blocked_rdev(mdk_rdev_t *rdev, mddev_t *mddev);
 extern void md_set_array_sectors(mddev_t *mddev, sector_t array_sectors);
 extern int md_check_no_bitmap(mddev_t *mddev);
 extern int md_integrity_register(mddev_t *mddev);
-void md_integrity_add_rdev(mdk_rdev_t *rdev, mddev_t *mddev);
+extern void md_integrity_add_rdev(mdk_rdev_t *rdev, mddev_t *mddev);
+extern int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale);
+extern void restore_bitmap_write_access(struct file *file);
 
 #endif /* _MD_MD_H */
diff --git a/drivers/md/multipath.c b/drivers/md/multipath.c
index ee7646f974a..32a662fc55c 100644
--- a/drivers/md/multipath.c
+++ b/drivers/md/multipath.c
@@ -145,7 +145,7 @@ static int multipath_make_request (struct request_queue *q, struct bio * bio)
 	int cpu;
 
 	if (unlikely(bio_rw_flagged(bio, BIO_RW_BARRIER))) {
-		bio_endio(bio, -EOPNOTSUPP);
+		md_barrier_request(mddev, bio);
 		return 0;
 	}
 
@@ -581,6 +581,7 @@ static void __exit multipath_exit (void)
 module_init(multipath_init);
 module_exit(multipath_exit);
 MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("simple multi-path personality for MD");
 MODULE_ALIAS("md-personality-7"); /* MULTIPATH */
 MODULE_ALIAS("md-multipath");
 MODULE_ALIAS("md-level--4");
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index d3a4ce06015..77605cdceaf 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -453,7 +453,7 @@ static int raid0_make_request(struct request_queue *q, struct bio *bio)
 	int cpu;
 
 	if (unlikely(bio_rw_flagged(bio, BIO_RW_BARRIER))) {
-		bio_endio(bio, -EOPNOTSUPP);
+		md_barrier_request(mddev, bio);
 		return 0;
 	}
 
@@ -567,6 +567,7 @@ static void raid0_exit (void)
 module_init(raid0_init);
 module_exit(raid0_exit);
 MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("RAID0 (striping) personality for MD");
 MODULE_ALIAS("md-personality-2"); /* RAID0 */
 MODULE_ALIAS("md-raid0");
 MODULE_ALIAS("md-level-0");
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index e07ce2e033a..859bd3ffe43 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -677,6 +677,7 @@ static void raise_barrier(conf_t *conf)
 static void lower_barrier(conf_t *conf)
 {
 	unsigned long flags;
+	BUG_ON(conf->barrier <= 0);
 	spin_lock_irqsave(&conf->resync_lock, flags);
 	conf->barrier--;
 	spin_unlock_irqrestore(&conf->resync_lock, flags);
@@ -801,6 +802,25 @@ static int make_request(struct request_queue *q, struct bio * bio)
 
 	md_write_start(mddev, bio); /* wait on superblock update early */
 
+	if (bio_data_dir(bio) == WRITE &&
+	    bio->bi_sector + bio->bi_size/512 > mddev->suspend_lo &&
+	    bio->bi_sector < mddev->suspend_hi) {
+		/* As the suspend_* range is controlled by
+		 * userspace, we want an interruptible
+		 * wait.
+		 */
+		DEFINE_WAIT(w);
+		for (;;) {
+			flush_signals(current);
+			prepare_to_wait(&conf->wait_barrier,
+					&w, TASK_INTERRUPTIBLE);
+			if (bio->bi_sector + bio->bi_size/512 <= mddev->suspend_lo ||
+			    bio->bi_sector >= mddev->suspend_hi)
+				break;
+			schedule();
+		}
+		finish_wait(&conf->wait_barrier, &w);
+	}
 	if (unlikely(!mddev->barriers_work &&
 		     bio_rw_flagged(bio, BIO_RW_BARRIER))) {
 		if (rw == WRITE)
@@ -923,7 +943,8 @@ static int make_request(struct request_queue *q, struct bio * bio)
 
 	/* do behind I/O ? */
 	if (bitmap &&
-	    atomic_read(&bitmap->behind_writes) < bitmap->max_write_behind &&
+	    (atomic_read(&bitmap->behind_writes)
+	     < mddev->bitmap_info.max_write_behind) &&
 	    (behind_pages = alloc_behind_pages(bio)) != NULL)
 		set_bit(R1BIO_BehindIO, &r1_bio->state);
 
@@ -1941,74 +1962,48 @@ static sector_t raid1_size(mddev_t *mddev, sector_t sectors, int raid_disks)
 	return mddev->dev_sectors;
 }
 
-static int run(mddev_t *mddev)
+static conf_t *setup_conf(mddev_t *mddev)
 {
 	conf_t *conf;
-	int i, j, disk_idx;
+	int i;
 	mirror_info_t *disk;
 	mdk_rdev_t *rdev;
+	int err = -ENOMEM;
 
-	if (mddev->level != 1) {
-		printk("raid1: %s: raid level not set to mirroring (%d)\n",
-		       mdname(mddev), mddev->level);
-		goto out;
-	}
-	if (mddev->reshape_position != MaxSector) {
-		printk("raid1: %s: reshape_position set but not supported\n",
-		       mdname(mddev));
-		goto out;
-	}
-	/*
-	 * copy the already verified devices into our private RAID1
-	 * bookkeeping area. [whatever we allocate in run(),
-	 * should be freed in stop()]
-	 */
 	conf = kzalloc(sizeof(conf_t), GFP_KERNEL);
-	mddev->private = conf;
 	if (!conf)
-		goto out_no_mem;
+		goto abort;
 
 	conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks,
 				 GFP_KERNEL);
 	if (!conf->mirrors)
-		goto out_no_mem;
+		goto abort;
 
 	conf->tmppage = alloc_page(GFP_KERNEL);
 	if (!conf->tmppage)
-		goto out_no_mem;
+		goto abort;
 
-	conf->poolinfo = kmalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
+	conf->poolinfo = kzalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
 	if (!conf->poolinfo)
-		goto out_no_mem;
-	conf->poolinfo->mddev = NULL;
+		goto abort;
 	conf->poolinfo->raid_disks = mddev->raid_disks;
 	conf->r1bio_pool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
 					  r1bio_pool_free,
 					  conf->poolinfo);
 	if (!conf->r1bio_pool)
-		goto out_no_mem;
+		goto abort;
+
 	conf->poolinfo->mddev = mddev;
 
 	spin_lock_init(&conf->device_lock);
-	mddev->queue->queue_lock = &conf->device_lock;
-
 	list_for_each_entry(rdev, &mddev->disks, same_set) {
-		disk_idx = rdev->raid_disk;
+		int disk_idx = rdev->raid_disk;
 		if (disk_idx >= mddev->raid_disks
 		    || disk_idx < 0)
 			continue;
 		disk = conf->mirrors + disk_idx;
 
 		disk->rdev = rdev;
-		disk_stack_limits(mddev->gendisk, rdev->bdev,
-				  rdev->data_offset << 9);
-		/* as we don't honour merge_bvec_fn, we must never risk
-		 * violating it, so limit ->max_sector to one PAGE, as
-		 * a one page request is never in violation.
-		 */
-		if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
-		    queue_max_sectors(mddev->queue) > (PAGE_SIZE>>9))
-			blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
 
 		disk->head_position = 0;
 	}
@@ -2022,8 +2017,7 @@ static int run(mddev_t *mddev)
 	bio_list_init(&conf->pending_bio_list);
 	bio_list_init(&conf->flushing_bio_list);
 
-
-	mddev->degraded = 0;
+	conf->last_used = -1;
 	for (i = 0; i < conf->raid_disks; i++) {
 
 		disk = conf->mirrors + i;
@@ -2031,38 +2025,97 @@ static int run(mddev_t *mddev)
 		if (!disk->rdev ||
 		    !test_bit(In_sync, &disk->rdev->flags)) {
 			disk->head_position = 0;
-			mddev->degraded++;
 			if (disk->rdev)
 				conf->fullsync = 1;
-		}
+		} else if (conf->last_used < 0)
+			/*
+			 * The first working device is used as a
+			 * starting point to read balancing.
+			 */
+			conf->last_used = i;
 	}
-	if (mddev->degraded == conf->raid_disks) {
+
+	err = -EIO;
+	if (conf->last_used < 0) {
 		printk(KERN_ERR "raid1: no operational mirrors for %s\n",
-			mdname(mddev));
-		goto out_free_conf;
+		       mdname(mddev));
+		goto abort;
 	}
-	if (conf->raid_disks - mddev->degraded == 1)
-		mddev->recovery_cp = MaxSector;
+	err = -ENOMEM;
+	conf->thread = md_register_thread(raid1d, mddev, NULL);
+	if (!conf->thread) {
+		printk(KERN_ERR
+		       "raid1: couldn't allocate thread for %s\n",
+		       mdname(mddev));
+		goto abort;
+	}
+
+	return conf;
+
+ abort:
+	if (conf) {
+		if (conf->r1bio_pool)
+			mempool_destroy(conf->r1bio_pool);
+		kfree(conf->mirrors);
+		safe_put_page(conf->tmppage);
+		kfree(conf->poolinfo);
+		kfree(conf);
+	}
+	return ERR_PTR(err);
+}
 
+static int run(mddev_t *mddev)
+{
+	conf_t *conf;
+	int i;
+	mdk_rdev_t *rdev;
+
+	if (mddev->level != 1) {
+		printk("raid1: %s: raid level not set to mirroring (%d)\n",
+		       mdname(mddev), mddev->level);
+		return -EIO;
+	}
+	if (mddev->reshape_position != MaxSector) {
+		printk("raid1: %s: reshape_position set but not supported\n",
+		       mdname(mddev));
+		return -EIO;
+	}
 	/*
-	 * find the first working one and use it as a starting point
-	 * to read balancing.
+	 * copy the already verified devices into our private RAID1
+	 * bookkeeping area. [whatever we allocate in run(),
+	 * should be freed in stop()]
 	 */
-	for (j = 0; j < conf->raid_disks &&
-		     (!conf->mirrors[j].rdev ||
-		      !test_bit(In_sync, &conf->mirrors[j].rdev->flags)) ; j++)
-		/* nothing */;
-	conf->last_used = j;
+	if (mddev->private == NULL)
+		conf = setup_conf(mddev);
+	else
+		conf = mddev->private;
 
+	if (IS_ERR(conf))
+		return PTR_ERR(conf);
 
-	mddev->thread = md_register_thread(raid1d, mddev, NULL);
-	if (!mddev->thread) {
-		printk(KERN_ERR
-		       "raid1: couldn't allocate thread for %s\n",
-		       mdname(mddev));
-		goto out_free_conf;
+	mddev->queue->queue_lock = &conf->device_lock;
+	list_for_each_entry(rdev, &mddev->disks, same_set) {
+		disk_stack_limits(mddev->gendisk, rdev->bdev,
+				  rdev->data_offset << 9);
+		/* as we don't honour merge_bvec_fn, we must never risk
+		 * violating it, so limit ->max_sector to one PAGE, as
+		 * a one page request is never in violation.
+		 */
+		if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
+		    queue_max_sectors(mddev->queue) > (PAGE_SIZE>>9))
+			blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
 	}
 
+	mddev->degraded = 0;
+	for (i=0; i < conf->raid_disks; i++)
+		if (conf->mirrors[i].rdev == NULL ||
+		    !test_bit(In_sync, &conf->mirrors[i].rdev->flags) ||
+		    test_bit(Faulty, &conf->mirrors[i].rdev->flags))
+			mddev->degraded++;
+
+	if (conf->raid_disks - mddev->degraded == 1)
+		mddev->recovery_cp = MaxSector;
+
 	if (mddev->recovery_cp != MaxSector)
 		printk(KERN_NOTICE "raid1: %s is not clean"
 		       " -- starting background reconstruction\n",
@@ -2071,9 +2124,14 @@ static int run(mddev_t *mddev)
 		"raid1: raid set %s active with %d out of %d mirrors\n",
 		mdname(mddev), mddev->raid_disks - mddev->degraded, 
 		mddev->raid_disks);
+
 	/*
 	 * Ok, everything is just fine now
 	 */
+	mddev->thread = conf->thread;
+	conf->thread = NULL;
+	mddev->private = conf;
+
 	md_set_array_sectors(mddev, raid1_size(mddev, 0, 0));
 
 	mddev->queue->unplug_fn = raid1_unplug;
@@ -2081,23 +2139,6 @@ static int run(mddev_t *mddev)
 	mddev->queue->backing_dev_info.congested_data = mddev;
 	md_integrity_register(mddev);
 	return 0;
-
-out_no_mem:
-	printk(KERN_ERR "raid1: couldn't allocate memory for %s\n",
-	       mdname(mddev));
-
-out_free_conf:
-	if (conf) {
-		if (conf->r1bio_pool)
-			mempool_destroy(conf->r1bio_pool);
-		kfree(conf->mirrors);
-		safe_put_page(conf->tmppage);
-		kfree(conf->poolinfo);
-		kfree(conf);
-		mddev->private = NULL;
-	}
-out:
-	return -EIO;
 }
 
 static int stop(mddev_t *mddev)
@@ -2271,6 +2312,9 @@ static void raid1_quiesce(mddev_t *mddev, int state)
 	conf_t *conf = mddev->private;
 
 	switch(state) {
+	case 2: /* wake for suspend */
+		wake_up(&conf->wait_barrier);
+		break;
 	case 1:
 		raise_barrier(conf);
 		break;
@@ -2280,6 +2324,23 @@ static void raid1_quiesce(mddev_t *mddev, int state)
 	}
 }
 
+static void *raid1_takeover(mddev_t *mddev)
+{
+	/* raid1 can take over:
+	 *  raid5 with 2 devices, any layout or chunk size
+	 */
+	if (mddev->level == 5 && mddev->raid_disks == 2) {
+		conf_t *conf;
+		mddev->new_level = 1;
+		mddev->new_layout = 0;
+		mddev->new_chunk_sectors = 0;
+		conf = setup_conf(mddev);
+		if (!IS_ERR(conf))
+			conf->barrier = 1;
+		return conf;
+	}
+	return ERR_PTR(-EINVAL);
+}
 
 static struct mdk_personality raid1_personality =
 {
@@ -2299,6 +2360,7 @@ static struct mdk_personality raid1_personality =
 	.size		= raid1_size,
 	.check_reshape	= raid1_reshape,
 	.quiesce	= raid1_quiesce,
+	.takeover	= raid1_takeover,
 };
 
 static int __init raid_init(void)
@@ -2314,6 +2376,7 @@ static void raid_exit(void)
 module_init(raid_init);
 module_exit(raid_exit);
 MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("RAID1 (mirroring) personality for MD");
 MODULE_ALIAS("md-personality-3"); /* RAID1 */
 MODULE_ALIAS("md-raid1");
 MODULE_ALIAS("md-level-1");
diff --git a/drivers/md/raid1.h b/drivers/md/raid1.h
index e87b84deff6..5f2d443ae28 100644
--- a/drivers/md/raid1.h
+++ b/drivers/md/raid1.h
@@ -59,6 +59,11 @@ struct r1_private_data_s {
 
 	mempool_t *r1bio_pool;
 	mempool_t *r1buf_pool;
+
+	/* When taking over an array from a different personality, we store
+	 * the new thread here until we fully activate the array.
+	 */
+	struct mdk_thread_s	*thread;
 };
 
 typedef struct r1_private_data_s conf_t;
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index c2cb7b87b44..d119b7b75e7 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -804,7 +804,7 @@ static int make_request(struct request_queue *q, struct bio * bio)
 	mdk_rdev_t *blocked_rdev;
 
 	if (unlikely(bio_rw_flagged(bio, BIO_RW_BARRIER))) {
-		bio_endio(bio, -EOPNOTSUPP);
+		md_barrier_request(mddev, bio);
 		return 0;
 	}
 
@@ -1432,6 +1432,43 @@ static void recovery_request_write(mddev_t *mddev, r10bio_t *r10_bio)
 
 
 /*
+ * Used by fix_read_error() to decay the per rdev read_errors.
+ * We halve the read error count for every hour that has elapsed
+ * since the last recorded read error.
+ *
+ */
+static void check_decay_read_errors(mddev_t *mddev, mdk_rdev_t *rdev)
+{
+	struct timespec cur_time_mon;
+	unsigned long hours_since_last;
+	unsigned int read_errors = atomic_read(&rdev->read_errors);
+
+	ktime_get_ts(&cur_time_mon);
+
+	if (rdev->last_read_error.tv_sec == 0 &&
+	    rdev->last_read_error.tv_nsec == 0) {
+		/* first time we've seen a read error */
+		rdev->last_read_error = cur_time_mon;
+		return;
+	}
+
+	hours_since_last = (cur_time_mon.tv_sec -
+			    rdev->last_read_error.tv_sec) / 3600;
+
+	rdev->last_read_error = cur_time_mon;
+
+	/*
+	 * if hours_since_last is > the number of bits in read_errors
+	 * just set read errors to 0. We do this to avoid
+	 * overflowing the shift of read_errors by hours_since_last.
+	 */
+	if (hours_since_last >= 8 * sizeof(read_errors))
+		atomic_set(&rdev->read_errors, 0);
+	else
+		atomic_set(&rdev->read_errors, read_errors >> hours_since_last);
+}
+
+/*
  * This is a kernel thread which:
  *
  *	1.	Retries failed read operations on working mirrors.
@@ -1444,6 +1481,43 @@ static void fix_read_error(conf_t *conf, mddev_t *mddev, r10bio_t *r10_bio)
 	int sect = 0; /* Offset from r10_bio->sector */
 	int sectors = r10_bio->sectors;
 	mdk_rdev_t*rdev;
+	int max_read_errors = atomic_read(&mddev->max_corr_read_errors);
+
+	rcu_read_lock();
+	{
+		int d = r10_bio->devs[r10_bio->read_slot].devnum;
+		char b[BDEVNAME_SIZE];
+		int cur_read_error_count = 0;
+
+		rdev = rcu_dereference(conf->mirrors[d].rdev);
+		bdevname(rdev->bdev, b);
+
+		if (test_bit(Faulty, &rdev->flags)) {
+			rcu_read_unlock();
+			/* drive has already been failed, just ignore any
+			   more fix_read_error() attempts */
+			return;
+		}
+
+		check_decay_read_errors(mddev, rdev);
+		atomic_inc(&rdev->read_errors);
+		cur_read_error_count = atomic_read(&rdev->read_errors);
+		if (cur_read_error_count > max_read_errors) {
+			rcu_read_unlock();
+			printk(KERN_NOTICE
+			       "raid10: %s: Raid device exceeded "
+			       "read_error threshold "
+			       "[cur %d:max %d]\n",
+			       b, cur_read_error_count, max_read_errors);
+			printk(KERN_NOTICE
+			       "raid10: %s: Failing raid "
+			       "device\n", b);
+			md_error(mddev, conf->mirrors[d].rdev);
+			return;
+		}
+	}
+	rcu_read_unlock();
+
 	while(sectors) {
 		int s = sectors;
 		int sl = r10_bio->read_slot;
@@ -1488,6 +1562,7 @@ static void fix_read_error(conf_t *conf, mddev_t *mddev, r10bio_t *r10_bio)
 		/* write it back and re-read */
 		rcu_read_lock();
 		while (sl != r10_bio->read_slot) {
+			char b[BDEVNAME_SIZE];
 			int d;
 			if (sl==0)
 				sl = conf->copies;
@@ -1503,9 +1578,21 @@ static void fix_read_error(conf_t *conf, mddev_t *mddev, r10bio_t *r10_bio)
 						 r10_bio->devs[sl].addr +
 						 sect + rdev->data_offset,
 						 s<<9, conf->tmppage, WRITE)
-				    == 0)
+				    == 0) {
 					/* Well, this device is dead */
+					printk(KERN_NOTICE
+					       "raid10:%s: read correction "
+					       "write failed"
+					       " (%d sectors at %llu on %s)\n",
+					       mdname(mddev), s,
+					       (unsigned long long)(sect+
+					       rdev->data_offset),
+					       bdevname(rdev->bdev, b));
+					printk(KERN_NOTICE "raid10:%s: failing "
+					       "drive\n",
+					       bdevname(rdev->bdev, b));
 					md_error(mddev, rdev);
+				}
 				rdev_dec_pending(rdev, mddev);
 				rcu_read_lock();
 			}
@@ -1526,10 +1613,22 @@ static void fix_read_error(conf_t *conf, mddev_t *mddev, r10bio_t *r10_bio)
 				if (sync_page_io(rdev->bdev,
 						 r10_bio->devs[sl].addr +
 						 sect + rdev->data_offset,
-						 s<<9, conf->tmppage, READ) == 0)
+						 s<<9, conf->tmppage,
+						 READ) == 0) {
 					/* Well, this device is dead */
+					printk(KERN_NOTICE
+					       "raid10:%s: unable to read back "
+					       "corrected sectors"
+					       " (%d sectors at %llu on %s)\n",
+					       mdname(mddev), s,
+					       (unsigned long long)(sect+
+						    rdev->data_offset),
+					       bdevname(rdev->bdev, b));
+					printk(KERN_NOTICE "raid10:%s: failing drive\n",
+					       bdevname(rdev->bdev, b));
+
 					md_error(mddev, rdev);
-				else
+				} else {
 					printk(KERN_INFO
 					       "raid10:%s: read error corrected"
 					       " (%d sectors at %llu on %s)\n",
@@ -1537,6 +1636,7 @@ static void fix_read_error(conf_t *conf, mddev_t *mddev, r10bio_t *r10_bio)
 					       (unsigned long long)(sect+
 					            rdev->data_offset),
 					       bdevname(rdev->bdev, b));
+				}
 
 				rdev_dec_pending(rdev, mddev);
 				rcu_read_lock();
@@ -2275,13 +2375,6 @@ static void raid10_quiesce(mddev_t *mddev, int state)
 		lower_barrier(conf);
 		break;
 	}
-	if (mddev->thread) {
-		if (mddev->bitmap)
-			mddev->thread->timeout = mddev->bitmap->daemon_sleep * HZ;
-		else
-			mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
-		md_wakeup_thread(mddev->thread);
-	}
 }
 
 static struct mdk_personality raid10_personality =
@@ -2315,6 +2408,7 @@ static void raid_exit(void)
 module_init(raid_init);
 module_exit(raid_exit);
 MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("RAID10 (striped mirror) personality for MD");
 MODULE_ALIAS("md-personality-9"); /* RAID10 */
 MODULE_ALIAS("md-raid10");
 MODULE_ALIAS("md-level-10");
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index d29215d966d..e84204eb12d 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -2947,6 +2947,7 @@ static void handle_stripe5(struct stripe_head *sh)
 	struct r5dev *dev;
 	mdk_rdev_t *blocked_rdev = NULL;
 	int prexor;
+	int dec_preread_active = 0;
 
 	memset(&s, 0, sizeof(s));
 	pr_debug("handling stripe %llu, state=%#lx cnt=%d, pd_idx=%d check:%d "
@@ -3096,12 +3097,8 @@ static void handle_stripe5(struct stripe_head *sh)
 					set_bit(STRIPE_INSYNC, &sh->state);
 			}
 		}
-		if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
-			atomic_dec(&conf->preread_active_stripes);
-			if (atomic_read(&conf->preread_active_stripes) <
-				IO_THRESHOLD)
-				md_wakeup_thread(conf->mddev->thread);
-		}
+		if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
+			dec_preread_active = 1;
 	}
 
 	/* Now to consider new write requests and what else, if anything
@@ -3208,6 +3205,16 @@ static void handle_stripe5(struct stripe_head *sh)
 
 	ops_run_io(sh, &s);
 
+	if (dec_preread_active) {
+		/* We delay this until after ops_run_io so that if make_request
+		 * is waiting on a barrier, it won't continue until the writes
+		 * have actually been submitted.
+		 */
+		atomic_dec(&conf->preread_active_stripes);
+		if (atomic_read(&conf->preread_active_stripes) <
+		    IO_THRESHOLD)
+			md_wakeup_thread(conf->mddev->thread);
+	}
 	return_io(return_bi);
 }
 
@@ -3221,6 +3228,7 @@ static void handle_stripe6(struct stripe_head *sh)
 	struct r6_state r6s;
 	struct r5dev *dev, *pdev, *qdev;
 	mdk_rdev_t *blocked_rdev = NULL;
+	int dec_preread_active = 0;
 
 	pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
 		"pd_idx=%d, qd_idx=%d\n, check:%d, reconstruct:%d\n",
@@ -3358,7 +3366,6 @@ static void handle_stripe6(struct stripe_head *sh)
 	 * completed
 	 */
 	if (sh->reconstruct_state == reconstruct_state_drain_result) {
-		int qd_idx = sh->qd_idx;
 
 		sh->reconstruct_state = reconstruct_state_idle;
 		/* All the 'written' buffers and the parity blocks are ready to
@@ -3380,12 +3387,8 @@ static void handle_stripe6(struct stripe_head *sh)
 					set_bit(STRIPE_INSYNC, &sh->state);
 			}
 		}
-		if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
-			atomic_dec(&conf->preread_active_stripes);
-			if (atomic_read(&conf->preread_active_stripes) <
-				IO_THRESHOLD)
-				md_wakeup_thread(conf->mddev->thread);
-		}
+		if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
+			dec_preread_active = 1;
 	}
 
 	/* Now to consider new write requests and what else, if anything
@@ -3494,6 +3497,18 @@ static void handle_stripe6(struct stripe_head *sh)
 
 	ops_run_io(sh, &s);
 
+
+	if (dec_preread_active) {
+		/* We delay this until after ops_run_io so that if make_request
+		 * is waiting on a barrier, it won't continue until the writes
+		 * have actually been submitted.
+		 */
+		atomic_dec(&conf->preread_active_stripes);
+		if (atomic_read(&conf->preread_active_stripes) <
+		    IO_THRESHOLD)
+			md_wakeup_thread(conf->mddev->thread);
+	}
+
 	return_io(return_bi);
 }
 
@@ -3741,7 +3756,7 @@ static int chunk_aligned_read(struct request_queue *q, struct bio * raid_bio)
 {
 	mddev_t *mddev = q->queuedata;
 	raid5_conf_t *conf = mddev->private;
-	unsigned int dd_idx;
+	int dd_idx;
 	struct bio* align_bi;
 	mdk_rdev_t *rdev;
 
@@ -3866,7 +3881,13 @@ static int make_request(struct request_queue *q, struct bio * bi)
 	int cpu, remaining;
 
 	if (unlikely(bio_rw_flagged(bi, BIO_RW_BARRIER))) {
-		bio_endio(bi, -EOPNOTSUPP);
+		/* Drain all pending writes.  We only really need
+		 * to ensure they have been submitted, but this is
+		 * easier.
+		 */
+		mddev->pers->quiesce(mddev, 1);
+		mddev->pers->quiesce(mddev, 0);
+		md_barrier_request(mddev, bi);
 		return 0;
 	}
 
@@ -3990,6 +4011,9 @@ static int make_request(struct request_queue *q, struct bio * bi)
 			finish_wait(&conf->wait_for_overlap, &w);
 			set_bit(STRIPE_HANDLE, &sh->state);
 			clear_bit(STRIPE_DELAYED, &sh->state);
+			if (mddev->barrier && 
+			    !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
+				atomic_inc(&conf->preread_active_stripes);
 			release_stripe(sh);
 		} else {
 			/* cannot get stripe for read-ahead, just give-up */
@@ -4009,6 +4033,14 @@ static int make_request(struct request_queue *q, struct bio * bi)
 
 		bio_endio(bi, 0);
 	}
+
+	if (mddev->barrier) {
+		/* We need to wait for the stripes to all be handled.
+		 * So: wait for preread_active_stripes to drop to 0.
+		 */
+		wait_event(mddev->thread->wqueue,
+			   atomic_read(&conf->preread_active_stripes) == 0);
+	}
 	return 0;
 }
 
@@ -5860,6 +5892,7 @@ static void raid5_exit(void)
 module_init(raid5_init);
 module_exit(raid5_exit);
 MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("RAID4/5/6 (striping with parity) personality for MD");
 MODULE_ALIAS("md-personality-4"); /* RAID5 */
 MODULE_ALIAS("md-raid5");
 MODULE_ALIAS("md-raid4");
diff --git a/drivers/md/raid6algos.c b/drivers/md/raid6algos.c
index 866215ac7f2..bffc61bff5a 100644
--- a/drivers/md/raid6algos.c
+++ b/drivers/md/raid6algos.c
@@ -31,25 +31,6 @@ EXPORT_SYMBOL(raid6_empty_zero_page);
 struct raid6_calls raid6_call;
 EXPORT_SYMBOL_GPL(raid6_call);
 
-/* Various routine sets */
-extern const struct raid6_calls raid6_intx1;
-extern const struct raid6_calls raid6_intx2;
-extern const struct raid6_calls raid6_intx4;
-extern const struct raid6_calls raid6_intx8;
-extern const struct raid6_calls raid6_intx16;
-extern const struct raid6_calls raid6_intx32;
-extern const struct raid6_calls raid6_mmxx1;
-extern const struct raid6_calls raid6_mmxx2;
-extern const struct raid6_calls raid6_sse1x1;
-extern const struct raid6_calls raid6_sse1x2;
-extern const struct raid6_calls raid6_sse2x1;
-extern const struct raid6_calls raid6_sse2x2;
-extern const struct raid6_calls raid6_sse2x4;
-extern const struct raid6_calls raid6_altivec1;
-extern const struct raid6_calls raid6_altivec2;
-extern const struct raid6_calls raid6_altivec4;
-extern const struct raid6_calls raid6_altivec8;
-
 const struct raid6_calls * const raid6_algos[] = {
 	&raid6_intx1,
 	&raid6_intx2,
@@ -169,3 +150,4 @@ static void raid6_exit(void)
 subsys_initcall(raid6_select_algo);
 module_exit(raid6_exit);
 MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("RAID6 Q-syndrome calculations");