[PATCH] md: Make sure QUEUE_FLAG_CLUSTER is set properly for md.

This flag should be set for a virtual device iff it is set for all underlying
devices.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

block/ll_rw_blk.c

@@ -785,6 +785,8 @@ void blk_queue_stack_limits(request_queue_t *t, request_queue_t *b)
 	t->max_hw_segments = min(t->max_hw_segments,b->max_hw_segments);
 	t->max_segment_size = min(t->max_segment_size,b->max_segment_size);
 	t->hardsect_size = max(t->hardsect_size,b->hardsect_size);
+	if (!test_bit(QUEUE_FLAG_CLUSTER, &b->queue_flags))
+		clear_bit(QUEUE_FLAG_CLUSTER, &t->queue_flags);
 }
 
 EXPORT_SYMBOL(blk_queue_stack_limits);

drivers/md/md.c

@@ -266,6 +266,7 @@ static mddev_t * mddev_find(dev_t unit)
 		kfree(new);
 		return NULL;
 	}
+	set_bit(QUEUE_FLAG_CLUSTER, &new->queue->queue_flags);
 
 	blk_queue_make_request(new->queue, md_fail_request);