[PATCH] dm: Handle READA requests in dm-mpath.c
READA errors failing with EWOULDBLOCK/EAGAIN do not constitute a valid
reason for failing the path; this lead to erratic errors on DM multipath
devices. This error can be safely propagated upwards without failing the
path.
Acked-by: Kevin Corry <kevcorry@us.ibm.com>
Acked-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Lars Marowsky-Bree <lmb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 1e97b3c..0c1b852 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -985,6 +985,9 @@
if (!error)
return 0; /* I/O complete */
+ if ((error == -EWOULDBLOCK) && bio_rw_ahead(bio))
+ return error;
+
spin_lock(&m->lock);
if (!m->nr_valid_paths) {
if (!m->queue_if_no_path || m->suspended) {