[PATCH 6/4] xfs/007: fix regressions on V4 filesystems

["Darrick J. Wong" <djwong@kernel.org>]

From: Darrick J. Wong <djwong@kernel.org>

Following commit eae40404, I noticed the following regression when
running a V4 fstests run on an 5.13 kernel:

--- /tmp/fstests/tests/xfs/007.out      2021-05-13 11:47:55.793859995 -0700
+++ /var/tmp/fstests/xfs/007.out.bad    2021-07-28 09:23:42.856000000 -0700
@@ -16,4 +16,4 @@
 *** umount
 *** Usage after quotarm ***
 core.nblocks = 0
-core.nblocks = 0
+core.nblocks = 1

The underlying cause of this problem is the fact that we now remount the
filesystem with no quota options because that will (soon) become the
only means to turn off quota accounting on XFS.  Because V4 filesystems
don't support simultaneous project and group quotas and play weird
remapping games with the incore superblock field, we actually have to
issue a remove command for the group quota file if we're trying to
truncate the project quota file on a V4 filesystem.

Due to stupid limitations in xfs_quota we actually have to issue a
separate 'remove' command.

Fixes: eae40404 ("xfs/007: unmount after disabling quota")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
 tests/xfs/007 |   19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/tests/xfs/007 b/tests/xfs/007
index 796db960..6d6d828b 100755
--- a/tests/xfs/007
+++ b/tests/xfs/007
@@ -43,10 +43,27 @@ do_test()
 	_qmount
 	echo "*** turn off $off_opts quotas"
 	$XFS_QUOTA_PROG -x -c "off -$off_opts" $SCRATCH_MNT
+
+	# Remount the filesystem with no quota options to force quotas off.
+	# This takes care of newer kernels where quotaoff clears the superblock
+	# quota enforcement flags but doesn't shut down accounting.
 	_scratch_unmount
 	_qmount_option ""
 	_scratch_mount
-	$XFS_QUOTA_PROG -x -c "remove -$off_opts" $SCRATCH_MNT
+
+	rm_commands=(-x -c "remove -$off_opts")
+
+	# Remounting a V4 fs with no quota options means that the internal
+	# gquotino -> pquotino remapping does not happen.  If we want to
+	# truncate the "project" quota file we must run remove -g.  However,
+	# xfs_quota has a nasty sharp edge wherein passing '-g' and '-p' only
+	# results in a QUOTARM call for the group quota file, so we must make
+	# a separate remove call.
+	[ $_fs_has_crcs == 0 ] && [ "$off_opts" = "up" ] && \
+		rm_commands+=(-c "remove -g")
+
+	$XFS_QUOTA_PROG "${rm_commands[@]}" $SCRATCH_MNT
+
 	echo "*** umount"
 	_scratch_unmount