From: Darrick J. Wong <darrick.w...@oracle.com>

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
script:

# 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
unlock.

Reported-by: benjamin.mo...@gmail.com
Fixes: 253f4911f297 ("xfs: better xfs_trans_alloc interface")
Signed-off-by: Darrick J. Wong <darrick.w...@oracle.com>
Reviewed-by: Dave Chinner <dchin...@redhat.com>
Tested-by: Salvatore Bonaccorso <car...@debian.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

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

--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -774,6 +774,7 @@ xfs_setattr_nonsize(
 
 out_cancel:
        xfs_trans_cancel(tp);
+       xfs_iunlock(ip, XFS_ILOCK_EXCL);
 out_dqrele:
        xfs_qm_dqrele(udqp);
        xfs_qm_dqrele(gdqp);


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