[PATCH] scsi: dm-mpath: do not fail paths when the target returns ALUA state transition

[Brian Bunker <brian@purestorage.com>]

When paths return an ALUA state transition, do not fail those paths.
The expectation is that the transition is short lived until the new
ALUA state is entered. There might not be other paths in an online
state to serve the request which can lead to an unexpected I/O error
on the multipath device.

Signed-off-by: Brian Bunker <brian@purestorage.com>
Acked-by: Krishna Kant <krishna.kant@purestorage.com>
Acked-by: Seamus Connor <sconnor@purestorage.com>
--
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index bced42f082b0..28948cc481f9 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -1652,12 +1652,12 @@ static int multipath_end_io(struct dm_target
*ti, struct request *clone,
        if (error && blk_path_error(error)) {
                struct multipath *m = ti->private;

-               if (error == BLK_STS_RESOURCE)
+               if (error == BLK_STS_RESOURCE || error == BLK_STS_AGAIN)
                        r = DM_ENDIO_DELAY_REQUEUE;
                else
                        r = DM_ENDIO_REQUEUE;

-               if (pgpath)
+               if (pgpath && (error != BLK_STS_AGAIN))
                        fail_path(pgpath);

                if (!atomic_read(&m->nr_valid_paths) &&
--

Thanks,
Brian

Brian Bunker
PURE Storage, Inc.
brian@purestorage.com