[PATCH] generic/050: handle f2fs as nojournal filesystem

[PATCH] generic/050: handle f2fs as nojournal filesystem

[Jan Prusakowski]

F2FS uses a checkpoint mechanism for metadata consistency rather than a
traditional journal. Roll-forward recovery is only needed if there are
fsync'd files since the last checkpoint.

In this test case, files are created without fsync, so there is no
roll-forward data to replay during mount.

Therefore, F2FS does not need to write to the device to recover, and
successfully mounts on the read-only block device. Thus, it should be
treated as nojournal in this case.

Signed-off-by: Jan Prusakowski <jprusakowski@google.com>
---
 tests/generic/050 | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/tests/generic/050 b/tests/generic/050
index 3bc37175..3a641a65 100755
--- a/tests/generic/050
+++ b/tests/generic/050
@@ -46,6 +46,18 @@ elif [ "$FSTYP" = "btrfs" ]; then
 	# So for this test case, btrfs will not get any dirty log tree thus
 	# it can be treated as "nojournal".
 	features="nojournal"
+elif [ "$FSTYP" = "f2fs" ]; then
+	# F2FS uses a checkpoint mechanism for metadata consistency rather than a
+	# traditional journal. Roll-forward recovery is only needed if there are
+	# fsync'd files since the last checkpoint.
+	#
+	# In this test case, files are created without fsync, so there is no
+	# roll-forward data to replay during mount.
+	#
+	# Therefore, F2FS does not need to write to the device to recover, and
+	# successfully mounts on the read-only block device. Thus, it should be
+	# treated as "nojournal" in this case.
+	features="nojournal"
 fi
 _link_out_file "$features"
 
-- 
2.53.0.1213.gd9a14994de-goog

Re: [PATCH] generic/050: handle f2fs as nojournal filesystem

[Christoph Hellwig]

On Fri, Apr 10, 2026 at 01:18:20PM +0000, Jan Prusakowski wrote:
> F2FS uses a checkpoint mechanism for metadata consistency rather than a
> traditional journal. Roll-forward recovery is only needed if there are
> fsync'd files since the last checkpoint.
> 
> In this test case, files are created without fsync, so there is no
> roll-forward data to replay during mount.
> 
> Therefore, F2FS does not need to write to the device to recover, and
> successfully mounts on the read-only block device. Thus, it should be
> treated as nojournal in this case.

This looks ok, but I always wonder if we want an opt-in for this
"journaling" behavior and/or define it clear in common/.