diff --git a/driver/device-mapper/device-mapper.h b/driver/device-mapper/device-mapper.h
index 9a6a48bb0..487fd8746 100644
--- a/driver/device-mapper/device-mapper.h
+++ b/driver/device-mapper/device-mapper.h
@@ -46,7 +46,8 @@ typedef int (*dm_ctr_fn)(struct dm_table *t,
 			 dm_error_fn fn, void *private);
 
 typedef void (*dm_dtr_fn)(struct dm_table *t, void *c);
-typedef int (*dm_map_fn)(struct buffer_head *bh, void *context);
+typedef int (*dm_map_fn)(struct buffer_head *bh, int rw, void *context);
+typedef int (*dm_err_fn)(struct buffer_head *bh, int rw, void *context);
 
 /*
  * information about a target type
@@ -59,6 +60,7 @@ struct target_type {
         dm_ctr_fn ctr;
         dm_dtr_fn dtr;
         dm_map_fn map;
+	dm_err_fn err;
 	unsigned long flags;
 };
 
diff --git a/driver/device-mapper/dm-linear.c b/driver/device-mapper/dm-linear.c
index 7264e0bf3..31400d7b7 100644
--- a/driver/device-mapper/dm-linear.c
+++ b/driver/device-mapper/dm-linear.c
@@ -103,7 +103,7 @@ static void linear_dtr(struct dm_table *t, void *c)
 	kfree(c);
 }
 
-static int linear_map(struct buffer_head *bh, void *context)
+static int linear_map(struct buffer_head *bh, int rw, void *context)
 {
 	struct linear_c *lc = (struct linear_c *) context;
 
diff --git a/driver/device-mapper/dm-target.c b/driver/device-mapper/dm-target.c
index 90770ab84..f92f5f2c0 100644
--- a/driver/device-mapper/dm-target.c
+++ b/driver/device-mapper/dm-target.c
@@ -134,7 +134,7 @@ static void io_err_dtr(struct dm_table *t, void *c)
 	/* empty */
 }
 
-static int io_err_map(struct buffer_head *bh, void *context)
+static int io_err_map(struct buffer_head *bh, int rw, void *context)
 {
 	buffer_IO_error(bh);
 	return 0;
diff --git a/driver/device-mapper/dm.c b/driver/device-mapper/dm.c
index 3332ba413..1ea0e4f06 100644
--- a/driver/device-mapper/dm.c
+++ b/driver/device-mapper/dm.c
@@ -48,6 +48,8 @@ int _version[3] = { 0, 1, 0 };
 
 struct io_hook {
 	struct mapped_device *md;
+	struct target *target;
+	int rw;
 	void (*end_io) (struct buffer_head * bh, int uptodate);
 	void *context;
 };
@@ -297,6 +299,11 @@ static void dec_pending(struct buffer_head *bh, int uptodate)
 {
 	struct io_hook *ih = bh->b_private;
 
+	if (!uptodate && ih->target->type->err) {
+		if (ih->target->type->err(bh, ih->rw, ih->target->private))
+			return;
+	}
+
 	if (atomic_dec_and_test(&ih->md->pending))
 		/* nudge anyone waiting on suspend queue */
 		wake_up(&ih->md->wait);
@@ -337,11 +344,11 @@ static int queue_io(struct mapped_device *md, struct buffer_head *bh, int rw)
  * do the bh mapping for a given leaf
  */
 static inline int __map_buffer(struct mapped_device *md,
-			       struct buffer_head *bh, int leaf)
+			       struct buffer_head *bh, int rw, int leaf)
 {
 	dm_map_fn fn;
 	void *context;
-	struct io_hook *ih = 0;
+	struct io_hook *ih = NULL;
 	int r;
 	struct target *ti = md->map->targets + leaf;
 
@@ -357,10 +364,12 @@ static inline int __map_buffer(struct mapped_device *md,
 		return 0;
 
 	ih->md = md;
+	ih->rw = rw;
+	ih->target = ti;
 	ih->end_io = bh->b_end_io;
 	ih->context = bh->b_private;
 
-	r = fn(bh, context);
+	r = fn(bh, rw, context);
 
 	if (r > 0) {
 		/* hook the end io request fn */
@@ -430,7 +439,7 @@ static int dm_user_bmap(struct inode *inode, struct lv_bmap *lvb)
 		struct target *t = md->map->targets + __find_node(md->map, &bh);
 		struct target_type *target = t->type;
 		if (target->flags & TF_BMAP) {
-			err = target->map(&bh, t->private);
+			err = target->map(&bh, READ, t->private);
 		}
 	}
 	up_read(&_dev_lock);
@@ -473,7 +482,7 @@ static int request(request_queue_t *q, int rw, struct buffer_head *bh)
 		down_read(&_dev_lock);	/* FIXME: there's still a race here */
 	}
 
-	if (!__map_buffer(md, bh, __find_node(md->map, bh)))
+	if (!__map_buffer(md, bh, rw, __find_node(md->map, bh)))
 		goto bad;
 
 	up_read(&_dev_lock);