diff -urN linux-2.6.12-00003/drivers/md/dm-log.h linux-2.6.12-00004/drivers/md/dm-log.h
--- linux-2.6.12-00003/drivers/md/dm-log.h	2005-07-20 16:27:00.000000000 -0500
+++ linux-2.6.12-00004/drivers/md/dm-log.h	2005-07-20 16:33:23.000000000 -0500
@@ -49,6 +49,16 @@
 	int (*is_clean)(struct dirty_log *log, region_t region);
 
 	/*
+	 * Returns: 0, 1
+	 *
+	 * This is necessary for cluster mirroring. It provides
+	 * a way to detect recovery on another node, so we
+	 * aren't writing concurrently.  This function is likely
+	 * to block (when a cluster log is used).
+	 */
+	int (*is_remote_recovering)(struct dirty_log *log, region_t region);
+
+	/*
 	 *  Returns: 0, 1, -EWOULDBLOCK, < 0
 	 *
 	 * A predicate function to check the area given by
diff -urN linux-2.6.12-00003/drivers/md/dm-raid1.c linux-2.6.12-00004/drivers/md/dm-raid1.c
--- linux-2.6.12-00003/drivers/md/dm-raid1.c	2005-07-20 16:32:08.000000000 -0500
+++ linux-2.6.12-00004/drivers/md/dm-raid1.c	2005-07-21 10:44:00.576555874 -0500
@@ -984,6 +984,9 @@
 	int state;
 	struct bio *bio;
 	struct bio_list sync, nosync, recover, *this_list = NULL;
+	struct bio_list requeue;
+	struct dirty_log *log = ms->rh.log;
+	region_t region;
 
 	if (!writes->head)
 		return;
@@ -994,9 +997,18 @@
 	bio_list_init(&sync);
 	bio_list_init(&nosync);
 	bio_list_init(&recover);
+	bio_list_init(&requeue);
 
 	while ((bio = bio_list_pop(writes))) {
-		state = rh_state(&ms->rh, bio_to_region(&ms->rh, bio), 1);
+		region = bio_to_region(&ms->rh, bio);
+
+		if (log->type->is_remote_recovering &&
+		    log->type->is_remote_recovering(log, region)) {
+			bio_list_add(&requeue, bio);
+			continue;
+		}
+
+		state = rh_state(&ms->rh, region, 1);
 		switch (state) {
 		case RH_CLEAN:
 		case RH_DIRTY:
@@ -1015,6 +1027,8 @@
 		bio_list_add(this_list, bio);
 	}
 
+	bio_list_merge(writes, &requeue);
+
 	/*
 	 * Increment the pending counts for any regions that will
 	 * be written to (writes to recover regions are going to