diff --git a/drivers/md/md.h b/drivers/md/md.h
index 7c930c0..d449d51 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -109,6 +109,14 @@ struct md_rdev {
 					   * for reporting to userspace and storing
 					   * in superblock.
 					   */
+
+	/*
+	 * The members for check collision of write behind IOs.
+	 */
+	struct list_head wb_list;
+	spinlock_t wb_list_lock;
+	wait_queue_head_t wb_io_wait;
+
 	struct work_struct del_work;	/* used for delayed sysfs removal */
 
 	struct kernfs_node *sysfs_state; /* handle for 'state'
@@ -193,6 +201,10 @@ enum flag_bits {
 				 * it didn't fail, so don't use FailFast
 				 * any more for metadata
 				 */
+	WBCollisionCheck,	/*
+				 * multiqueue device should check if there
+				 * is collision between write behind bios.
+				 */
 };
 
 static inline int is_badblock(struct md_rdev *rdev, sector_t s, int sectors,
@@ -245,6 +257,14 @@ enum mddev_sb_flags {
 	MD_SB_NEED_REWRITE,	/* metadata write needs to be repeated */
 };
 
+#define NR_WB_INFOS	8
+/* record current range of write behind IOs */
+struct wb_info {
+	sector_t lo;
+	sector_t hi;
+	struct list_head list;
+};
+
 struct mddev {
 	void				*private;
 	struct md_personality		*pers;
@@ -461,6 +481,7 @@ struct mddev {
 					  */
 	struct work_struct flush_work;
 	struct work_struct event_work;	/* used by dm to report failure event */
+	mempool_t *wb_info_pool;
 	void (*sync_super)(struct mddev *mddev, struct md_rdev *rdev);
 	struct md_cluster_info		*cluster_info;
 	unsigned int			good_device_nr;	/* good device num within cluster raid */