[PATCH v10 3/6] common/rc: add _scratch_{u}mount_idmapped() helpers

[Christian Brauner <brauner@kernel.org>]

From: Christian Brauner <christian.brauner@ubuntu.com>

They will be used in follow-up patches for xfs quota tests but might be
useful for other tests in the future.

Cc: Eryu Guan <guan@eryu.me>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: fstests@vger.kernel.org
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
---
 common/rc | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/common/rc b/common/rc
index a8b375a2..351996fc 100644
--- a/common/rc
+++ b/common/rc
@@ -342,6 +342,36 @@ _scratch_mount()
 	_try_scratch_mount $* || _fail "mount failed"
 }
 
+_scratch_mount_idmapped()
+{
+	local type="$1"
+	local id="$2"
+
+	if [ "$type" = "u" ]; then
+		# This means root will be able to create files as uid %id in
+		# the underlying filesystem by going through the idmapped mount.
+		$here/src/idmapped-mounts/mount-idmapped --map-mount u:0:$id:1 \
+							 --map-mount u:$id:0:1 \
+							 --map-mount g:0:0:1 \
+							 "$SCRATCH_MNT" "$SCRATCH_MNT" || _fail "mount-idmapped failed"
+	elif [ "$type" = "g" ]; then
+		# This means root will be able to create files as gid %id in
+		# the underlying filesystem by going through the idmapped mount.
+		$here/src/idmapped-mounts/mount-idmapped --map-mount g:0:$id:1 \
+							 --map-mount g:$id:0:1 \
+							 --map-mount u:0:0:1 \
+							 "$SCRATCH_MNT" "$SCRATCH_MNT" || _fail "mount-idmapped failed"
+	elif [ "$type" = "b" ]; then
+		# This means root will be able to create files as uid and gid
+		# %id in the underlying filesystem by going through the idmapped mount.
+		$here/src/idmapped-mounts/mount-idmapped --map-mount b:0:$id:1 \
+							 --map-mount b:$id:0:1 \
+							 "$SCRATCH_MNT" "$SCRATCH_MNT" || _fail "mount-idmapped failed"
+	else
+		_fail "usage: either \"u\" (uid), \"g\" (gid), or \"b\" (uid and gid) must be specified "
+	fi
+}
+
 _scratch_unmount()
 {
 	case "$FSTYP" in
@@ -357,6 +387,11 @@ _scratch_unmount()
 	esac
 }
 
+_scratch_umount_idmapped()
+{
+	$UMOUNT_PROG $SCRATCH_MNT
+}
+
 _scratch_remount()
 {
     local opts="$1"
-- 
2.27.0