On Mon, Dec 14, 2020 at 12:18:54PM -0500, Brian Foster wrote: > cgroup writeback accounting does not track partition level > statistics. Instead, I/O is accounted against the parent device. As > a result, the test fails if the scratch device happens to be a > device partition. Since parent level stats are potentially polluted > by factors external to the test, wrap the scratch device in a > loopback device to guarantee the test always runs on a top-level > block device. > > Reported-by: Boyang Xue <bxue@xxxxxxxxxx> > Signed-off-by: Brian Foster <bfoster@xxxxxxxxxx> > --- > > v2: > - Use _require_scratch_nocheck() since the scratch device is not used > directly. V2 looks good to me, thanks Brian. Reviewed-by: Zorro Lang <zlang@xxxxxxxxxx> > v1: https://lore.kernel.org/fstests/20201210161426.1927144-1-bfoster@xxxxxxxxxx/ > > tests/generic/563 | 23 +++++++++++++++-------- > 1 file changed, 15 insertions(+), 8 deletions(-) > > diff --git a/tests/generic/563 b/tests/generic/563 > index 51deaa2f..b113eacf 100755 > --- a/tests/generic/563 > +++ b/tests/generic/563 > @@ -2,7 +2,7 @@ > # SPDX-License-Identifier: GPL-2.0 > # Copyright (c) 2019 Red Hat, Inc. All Rights Reserved. > # > -# FS QA Test No. 011 > +# FS QA Test No. 563 > # > # This test verifies that cgroup aware writeback properly accounts I/Os in > # various scenarios. We perform reads/writes from different combinations of > @@ -26,6 +26,8 @@ _cleanup() > > echo $$ > $cgdir/cgroup.procs > rmdir $cgdir/$seq-cg* > /dev/null 2>&1 > + umount $SCRATCH_MNT > /dev/null 2>&1 > + _destroy_loop_device $LOOP_DEV > /dev/null 2>&1 > } > > # get standard environment, filters and checks > @@ -40,16 +42,14 @@ rm -f $seqres.full > > # Modify as appropriate. > _supported_fs generic > -_require_scratch > +_require_scratch_nocheck > _require_cgroup2 io > +_require_loop > > # cgroup v2 writeback is only support on block devices so far > _require_block_device $SCRATCH_DEV > > -smajor=$((0x`stat -L -c %t $SCRATCH_DEV`)) > -sminor=$((0x`stat -L -c %T $SCRATCH_DEV`)) > cgdir=$CGROUP2_PATH > - > iosize=$((1024 * 1024 * 8)) > > # Check cgroup read/write charges against expected values. Allow for some > @@ -89,12 +89,19 @@ reset() > rmdir $cgdir/$seq-cg* > /dev/null 2>&1 > $XFS_IO_PROG -fc "pwrite 0 $iosize" $SCRATCH_MNT/file \ > >> $seqres.full 2>&1 > - _scratch_cycle_mount || _fail "mount failed" > + umount $SCRATCH_MNT || _fail "umount failed" > + _mount $LOOP_DEV $SCRATCH_MNT || _fail "mount failed" > stat $SCRATCH_MNT/file > /dev/null > } > > -_scratch_mkfs >> $seqres.full 2>&1 > -_scratch_mount > +# cgroup I/O accounting doesn't work on partitions. Use a loop device to rule > +# that out. > +LOOP_DEV=$(_create_loop_device $SCRATCH_DEV) > +smajor=$((0x`stat -L -c %t $LOOP_DEV`)) > +sminor=$((0x`stat -L -c %T $LOOP_DEV`)) > + > +_mkfs_dev $LOOP_DEV >> $seqres.full 2>&1 > +_mount $LOOP_DEV $SCRATCH_MNT || _fail "mount failed" > > echo "+io" > $cgdir/cgroup.subtree_control || _fail "subtree control" > > -- > 2.26.2 >
