xfs: fix missing ILOCK unlock when xfs_setattr_nonsize fails due to EDQUOT

debian/changelog

@@ -3,6 +3,7 @@ linux (4.19.67-2) UNRELEASED; urgency=medium
   [ Salvatore Bonaccorso ]
   * dm: disable DISCARD if the underlying storage no longer supports it
     (Closes: #934331)
+  * xfs: fix missing ILOCK unlock when xfs_setattr_nonsize fails due to EDQUOT
 
   [ Ben Hutchings ]
   * KVM: Ignore ABI changes

debian/patches/bugfix/all/xfs-fix-missing-ILOCK-unlock-when-xfs_setattr_nonsiz.patch

@@ -0,0 +1,62 @@
+From: "Darrick J. Wong" <darrick.wong@oracle.com>
+Date: Thu, 22 Aug 2019 20:55:28 -0700
+Subject: xfs: fix missing ILOCK unlock when xfs_setattr_nonsize fails due to EDQUOT
+Origin: https://git.kernel.org/linus/1fb254aa983bf190cfd685d40c64a480a9bafaee
+
+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.moody@gmail.com
+Fixes: 253f4911f297 ("xfs: better xfs_trans_alloc interface")
+Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
+Reviewed-by: Dave Chinner <dchinner@redhat.com>
+Tested-by: Salvatore Bonaccorso <carnil@debian.org>
+---
+ fs/xfs/xfs_iops.c | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
+index ff3c1fae5357..fe285d123d69 100644
+--- a/fs/xfs/xfs_iops.c
++++ b/fs/xfs/xfs_iops.c
+@@ -793,6 +793,7 @@ 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);
+-- 
+2.23.0
+

debian/patches/series

@@ -104,6 +104,7 @@ debian/revert-objtool-fix-config_stack_validation-y-warning.patch
 bugfix/all/mt76-use-the-correct-hweight8-function.patch
 bugfix/all/rtc-s35390a-set-uie_unsupported.patch
 bugfix/all/dm-disable-discard-if-the-underlying-storage-no-longer-supports-it.patch
+bugfix/all/xfs-fix-missing-ILOCK-unlock-when-xfs_setattr_nonsiz.patch
 
 # Miscellaneous features