generic/563: selectively remove the io cgroup controller

If a system configuration tool such as systemd sets up the io cgroup
controller for its own purposes, it's possible that the last line of
this test will not be able to remove the io controller from the system
configuration.  This causes the test to fail even though the inability
to tear down systemd should not be considered (in this case) a failure.

Change this test to set the "io" component of subtree control back to
whatever it was when the test started.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>

diff --git a/tests/generic/563 b/tests/generic/563
index b113eacf60e7eb4f5e87e45663e73fc23cb2bf1b..fe7394c0910ce1dad507e4d1a6f1244ac694e2fd 100755 (executable)
--- a/tests/generic/563
+++ b/tests/generic/563
@@ -103,6 +103,9 @@ sminor=$((0x`stat -L -c %T $LOOP_DEV`))
 _mkfs_dev $LOOP_DEV >> $seqres.full 2>&1
 _mount $LOOP_DEV $SCRATCH_MNT || _fail "mount failed"
 
+drop_io_cgroup=
+grep -q -w io $cgdir/cgroup.subtree_control || drop_io_cgroup=1
+
 echo "+io" > $cgdir/cgroup.subtree_control || _fail "subtree control"
 
 # Read and write from a single group.
@@ -143,7 +146,9 @@ $XFS_IO_PROG -c fsync $SCRATCH_MNT/file
 check_cg $cgdir/$seq-cg $iosize $iosize
 check_cg $cgdir/$seq-cg-2 0 0
 
-echo "-io" > $cgdir/cgroup.subtree_control || _fail "subtree control"
+if [ "$drop_io_cgroup" = 1 ]; then
+       echo "-io" > $cgdir/cgroup.subtree_control || _fail "subtree control"
+fi
 
 # success, all done
 status=0