Fiona reported that an ext4 filesystem on top of LVM can sometimes
report over-allocation to du (based on the heuristics the filesystem
is making while observing the contents being mirrored); even though
the contents and actual size matched, about 50% of the time the size
reported by disk_usage was too large by 4k, failing the test. In
auditing other iotests, this is a common problem we've had to deal
with.
Meanwhile, Markus reported that an xfs filesystem reports disk usage
at a default granularity of 1M (so the sparse file occupies 3M, since
it has just over 2M data).
Reported-by: Fiona Ebner <f.eb...@proxmox.com>
Reported-by: Markus Armbruster <arm...@redhat.com>
Fixes: c0ddcb2c ("tests: Add iotest mirror-sparse for recent patches")
Signed-off-by: Eric Blake <ebl...@redhat.com>
Reviewed-by: Fiona Ebner <f.eb...@proxmox.com>
Tested-by: Fiona Ebner <f.eb...@proxmox.com>
Message-ID: <20250523163041.2548675-7-ebl...@redhat.com>
[eblake: Also fix xfs issue]
Signed-off-by: Eric Blake <ebl...@redhat.com>
---
tests/qemu-iotests/tests/mirror-sparse | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/tests/qemu-iotests/tests/mirror-sparse
b/tests/qemu-iotests/tests/mirror-sparse
index 8c52a4e2448..11418c08713 100755
--- a/tests/qemu-iotests/tests/mirror-sparse
+++ b/tests/qemu-iotests/tests/mirror-sparse
@@ -96,13 +96,15 @@ _send_qemu_cmd $h1 '{"execute": "blockdev-del", "arguments":
{"node-name": "dst"}}' 'return' \
| _filter_block_job_offset | _filter_block_job_len
$QEMU_IMG compare -U -f $IMGFMT -F raw $TEST_IMG.base $TEST_IMG
+# Some filesystems can fudge allocations for various reasons; rather
+# than expecting precise 2M and 20M images, it is better to allow for slop.
result=$(disk_usage $TEST_IMG)
-if test $result -lt $((3*1024*1024)); then
+if test $result -lt $((4*1024*1024)); then
actual=sparse
-elif test $result = $((20*1024*1024)); then
+elif test $result -gt $((19*1024*1024)); then
actual=full
else
- actual=unknown
+ actual="unexpected size ($result)"
fi
echo "Destination is $actual; expected $expected"
}
--
2.49.0
