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

[Kamal Mostafa]

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-3.8.y-queue branch of the 3.8.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-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.20.

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

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 47e1089696e323029c6c13d56f4b4023548deaae 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: Kamal Mostafa <kamal 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 9d11b4e..a555bc7 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -1598,8 +1598,11 @@ 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);
--
1.8.3.2