Running btrfs/239 on a zoned device often fails with the following error.
btrfs/239 5s ... - output mismatch (see /host/btrfs/239.out.bad)
--- tests/btrfs/239.out 2023-09-21 16:56:37.735204924 +0900
+++ /host/btrfs/239.out.bad 2023-09-21 18:22:45.401433408 +0900
@@ -1,4 +1,6 @@
QA output created by 239
+/testdir/dira still exists
+/dira does not exists
File SCRATCH_MNT/testdir/file1 data:
0000000 ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab
*
...
This happens because "testdir" and "dira" are not logged on the first fsync
(fsync $SCRATCH_MNT/testdir), but are written as a full commit. That
prevents updating the log on "mv" time, leaving them pre-mv state.
The full commit is induced by the creation of a new block group. On the
zoned mode, we use a dedicated block group for tree-log. That block group
is created on-demand or assigned to a metadata block group if there is
none. On the first mount of a file system, we need to create one because
there is only one metadata block group available for the regular
metadata. That creation of a new block group forces tree-log to be a full
commit on that transaction, which prevents logging "testdir" and "dira".
Fix the issue by calling fsync before the first "sync", which creates the
dedicated block group and let the files be properly logged.
Signed-off-by: Naohiro Aota <naohiro.aota@xxxxxxx>
---
tests/btrfs/239 | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/tests/btrfs/239 b/tests/btrfs/239
index 3fbeaedd2c39..5a2dbe58d5fb 100755
--- a/tests/btrfs/239
+++ b/tests/btrfs/239
@@ -83,6 +83,18 @@ done
#
mkdir $SCRATCH_MNT/testdir/dira
+# This fsync is for the zoned mode. On the zoned mode, we use a dedicated block
+# group for tree-log. That block group is created on-demand or assigned to a
+# metadata block group if there is none. On the first mount of a file system, we
+# need to create one because there is only one metadata block group available
+# for the regular metadata. That creation of a new block group forces tree-log
+# to be a full commit on that transaction, which prevents logging "testdir" and
+# "dira" and screws up the result.
+#
+# Calling fsync here will create the dedicated block group, and let them be
+# logged.
+$XFS_IO_PROG -c "fsync" $SCRATCH_MNT
+
# Make sure everything done so far is durably persisted.
sync
--
2.42.0
