[PATCH 5.2 154/162] xfs: fix missing ILOCK unlock when xfs_setattr_nonsize fails due to EDQUOT

From: Greg Kroah-Hartman
Date: Tue Aug 27 2019 - 04:07:20 EST

From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>

commit 1fb254aa983bf190cfd685d40c64a480a9bafaee upstream.

Benjamin Moody reported to Debian that XFS partially wedges when a chgrp
fails on account of being out of disk quota. I ran his reproducer

# adduser dummy
# adduser dummy plugdev

# dd if=/dev/zero bs=1M count=100 of=test.img
# mkfs.xfs test.img
# mount -t xfs -o gquota test.img /mnt
# mkdir -p /mnt/dummy
# chown -c dummy /mnt/dummy
# xfs_quota -xc 'limit -g bsoft=100k bhard=100k plugdev' /mnt

(and then as user dummy)

$ dd if=/dev/urandom bs=1M count=50 of=/mnt/dummy/foo
$ chgrp plugdev /mnt/dummy/foo

and saw:

WARNING: lock held when returning to user space!
5.3.0-rc5 #rc5 Tainted: G W
chgrp/47006 is leaving the kernel with locks still held!
1 lock held by chgrp/47006:
#0: 000000006664ea2d (&xfs_nondir_ilock_class){++++}, at: xfs_ilock+0xd2/0x290 [xfs]

...which is clearly caused by xfs_setattr_nonsize failing to unlock the
ILOCK after the xfs_qm_vop_chown_reserve call fails. Add the missing

Reported-by: benjamin.moody@xxxxxxxxx
Fixes: 253f4911f297 ("xfs: better xfs_trans_alloc interface")
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Reviewed-by: Dave Chinner <dchinner@xxxxxxxxxx>
Tested-by: Salvatore Bonaccorso <carnil@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

fs/xfs/xfs_iops.c | 1 +
1 file changed, 1 insertion(+)

--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -803,6 +803,7 @@ xfs_setattr_nonsize(

+ xfs_iunlock(ip, XFS_ILOCK_EXCL);