[3.11.y.z extended stable] Patch "dm mpath: fix stalls when handling invalid ioctls" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    dm mpath: fix stalls when handling invalid ioctls

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From b3ddd7a4c73e9091799f6952a8b3b7e2088f104a Mon Sep 17 00:00:00 2001
From: Hannes Reinecke <hare at suse.de>
Date: Wed, 26 Feb 2014 10:07:04 +0100
Subject: dm mpath: fix stalls when handling invalid ioctls

commit a1989b330093578ea5470bea0a00f940c444c466 upstream.

An invalid ioctl will never be valid, irrespective of whether multipath
has active paths or not.  So for invalid ioctls we do not have to wait
for multipath to activate any paths, but can rather return an error
code immediately.  This fix resolves numerous instances of:

 udevd[]: worker [] unexpectedly returned with status 0x0100

that have been seen during testing.

Signed-off-by: Hannes Reinecke <hare at suse.de>
Signed-off-by: Mike Snitzer <snitzer at redhat.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/md/dm-mpath.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index eb7ddb2..0ba21b0 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -1608,8 +1608,11 @@ static int multipath_ioctl(struct dm_target *ti, unsigned int cmd,
 	/*
 	 * Only pass ioctls through if the device sizes match exactly.
 	 */
-	if (!r && ti->len != i_size_read(bdev->bd_inode) >> SECTOR_SHIFT)
-		r = scsi_verify_blk_ioctl(NULL, cmd);
+	if (!bdev || ti->len != i_size_read(bdev->bd_inode) >> SECTOR_SHIFT) {
+		int err = scsi_verify_blk_ioctl(NULL, cmd);
+		if (err)
+			r = err;
+	}

 	if (r == -ENOTCONN && !fatal_signal_pending(current))
 		queue_work(kmultipathd, &m->process_queued_ios);
--
1.9.0