From: Lars Marowsky-Bree <lmb@suse.de>
Date: Wed, 8 Jun 2005 22:50:31 +0000 (-0700)
Subject: [PATCH] dm: Handle READA requests in dm-mpath.c
X-Git-Tag: v2.6.12~55
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4f58802fae8a51d9e79454746584175c14f84519;p=linux-2.6

[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 1e97b3c12b..0c1b8520ef 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -985,6 +985,9 @@ static int do_end_io(struct multipath *m, struct bio *bio,
 	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) {