[PATCH] common: add scoutfs support.

[PATCH] common: add scoutfs support.

[Auke Kok]

Basic scoutfs support: scoutfs uses 2 devices for a filesystem, one for
metadata, and one for data. This requires that we pass a metadev_path
argument to every mount call, as well as a quorum_slot option.

To run any of these tests on scoutfs, you'll need to build and
install the out-of-tree kernel module `scoutfs.ko`, and the `scoutfs`
userspace utility, which can `mkfs` a scoutfs filesystem. The tests
themselves are unmodified - many of them will be skipped due to
unsupported features.

Signed-off-by: Auke Kok <auke.kok@versity.com>
---
 common/config |  1 +
 common/rc     | 26 ++++++++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/common/config b/common/config
index 22b52432..5273790d 100644
--- a/common/config
+++ b/common/config
@@ -228,6 +228,7 @@ export BTRFS_MAP_LOGICAL_PROG=$(type -P btrfs-map-logical)
 export PARTED_PROG="$(type -P parted)"
 export XFS_PROPERTY_PROG="$(type -P xfs_property)"
 export FSCRYPTCTL_PROG="$(type -P fscryptctl)"
+export SCOUTFS_PROG="$(type -P scoutfs)"
 
 # udev wait functions.
 #
diff --git a/common/rc b/common/rc
index f71cc8f0..47aac12b 100644
--- a/common/rc
+++ b/common/rc
@@ -361,6 +361,9 @@ _scratch_options()
     ext2|ext3|ext4)
 	_scratch_ext4_options "$@"
 	;;
+    scoutfs)
+	SCRATCH_OPTIONS=$SCOUTFS_SCRATCH_MOUNT_OPTIONS_META_DEV
+	;;
     esac
 }
 
@@ -396,7 +399,14 @@ _test_options()
 # hosted on $SCRATCH_DEV, so can't use external scratch devices).
 _common_dev_mount_options()
 {
+    case "$FSTYPE" in
+    scoutfs)
+	echo $MOUNT_OPTIONS $SELINUX_MOUNT_OPTIONS $SCOUTFS_MOUNT_OPTIONS_META_DEV $*
+	;;
+    *)
 	echo $MOUNT_OPTIONS $SELINUX_MOUNT_OPTIONS $*
+	;;
+    esac
 }
 
 _scratch_mount_options()
@@ -851,6 +861,9 @@ _test_mkfs()
     bcachefs)
 	$MKFS_BCACHEFS_PROG $MKFS_OPTIONS $* $TEST_DEV > /dev/null
 	;;
+    scoutfs)
+	$SCOUTFS_PROG mkfs $MKFS_OPTIONS $* $TEST_DEV
+	;;
     *)
 	yes | $MKFS_PROG -t $FSTYP -- $MKFS_OPTIONS $* $TEST_DEV
 	;;
@@ -896,6 +909,9 @@ _try_mkfs_dev()
     xfs)
 	$MKFS_PROG -t $FSTYP -- -f $MKFS_OPTIONS $*
 	;;
+    scoutfs)
+	$SCOUTFS_PROG mkfs $MKFS_OPTIONS $*
+	;;
     *)
 	yes | $MKFS_PROG -t $FSTYP -- $MKFS_OPTIONS $*
 	;;
@@ -1003,6 +1019,10 @@ _scratch_mkfs()
 		mkfs_cmd="$MKFS_BCACHEFS_PROG"
 		mkfs_filter="cat"
 		;;
+     scoutfs)
+		mkfs_cmd="$SCOUTFS_PROG mkfs $MKFS_OPTIONS $MKFS_SCRATCH_OPTIONS $* $SCRATCH_META_DEV"
+		mkfs_filter="cat"
+		;;
 	*)
 		mkfs_cmd="yes | $MKFS_PROG -t $FSTYP --"
 		mkfs_filter="cat"
@@ -3670,6 +3690,9 @@ _check_test_fs()
     f2fs)
         _check_f2fs_filesystem $TEST_DEV
         ;;
+    scoutfs)
+	# currently not checking
+	;;
     *)
 	_check_generic_filesystem $TEST_DEV
 	;;
@@ -3729,6 +3752,9 @@ _check_scratch_fs()
     f2fs)
         _check_f2fs_filesystem $device
         ;;
+    scoutfs)
+	# currently not checking
+	;;
     *)
 	_check_generic_filesystem $device
 	;;
-- 
2.49.0

Re: [PATCH] common: add scoutfs support.

[Christoph Hellwig]

On Fri, Jun 27, 2025 at 11:42:20AM -0700, Auke Kok wrote:
> Basic scoutfs support: scoutfs uses 2 devices for a filesystem, one for
> metadata, and one for data. This requires that we pass a metadev_path
> argument to every mount call, as well as a quorum_slot option.
> 
> To run any of these tests on scoutfs, you'll need to build and
> install the out-of-tree kernel module `scoutfs.ko`, and the `scoutfs`
> userspace utility, which can `mkfs` a scoutfs filesystem. The tests
> themselves are unmodified - many of them will be skipped due to
> unsupported features.

xfstests is only really intended to test in-tree file systems, or at
least those submitted upstream for inclusion and still in-progress.

Re: [PATCH] common: add scoutfs support.

[Auke Kok]

On 6/29/25 10:38 PM, Christoph Hellwig wrote:
> xfstests is only really intended to test in-tree file systems, or at
> least those submitted upstream for inclusion and still in-progress.

I hear you. I don't think this will ever happen.

We've been using xfstests to test scoutfs for many years and rely 
heavily on it, running it practically non-stop on scoutfs in our own CI 
infrastructure, so I thought I'd at least test the waters as I'm in the 
process of updating our local copy of it.

It's entirely likely we'll be maintaining scoutfs for a very long time 
given our main users are deploying large scale archives with it that 
have extensive lifetime spans.

Either way it's no big issue for me/us - this patch is rather small and 
trivial. I do personally prefer to push things upstream once in a while 
to see what feedback comes back, hence this post.

Auke