From b414487e555d483f893e65d86b75e57d7721710b Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <djwong@kernel.org>
Date: Thu, 20 Feb 2025 13:47:05 -0800
Subject: [PATCH] common/populate: refactor caching of metadumps to a helper

Hoist out of _scratch_populate_cached all the code that we use to save a
metadump of the populated filesystem.  We're going to make this more
involved for XFS in the next few patches so that we can take advantage
of the new support for external devices in metadump/mdrestore.

Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Zorro Lang <zlang@kernel.org>
---
 common/populate | 37 ++++++++++++++++++++++++++++---------
 1 file changed, 28 insertions(+), 9 deletions(-)

diff --git a/common/populate b/common/populate
index 7690f269..627e8ca4 100644
--- a/common/populate
+++ b/common/populate
@@ -1064,6 +1064,31 @@ _scratch_populate_restore_cached() {
 	return 1
 }
 
+# Take a metadump of the scratch filesystem and cache it for later.
+_scratch_populate_save_metadump()
+{
+	local metadump_file="$1"
+
+	case "${FSTYP}" in
+	"xfs")
+		local logdev=none
+		[ "$USE_EXTERNAL" = yes -a ! -z "$SCRATCH_LOGDEV" ] && \
+			logdev=$SCRATCH_LOGDEV
+
+		_xfs_metadump "$metadump_file" "$SCRATCH_DEV" "$logdev" \
+				compress -a -o
+		res=$?
+		;;
+	"ext2"|"ext3"|"ext4")
+		_ext4_metadump "${SCRATCH_DEV}" "${metadump_file}" compress
+		res=$?
+		;;
+	*)
+		_fail "Don't know how to save a ${FSTYP} filesystem."
+	esac
+	return $res
+}
+
 # Populate a scratch FS from scratch or from a cached image.
 _scratch_populate_cached() {
 	local meta_descr="$(_scratch_populate_cache_tag "$@")"
@@ -1087,26 +1112,20 @@ _scratch_populate_cached() {
 
 	# Oh well, just create one from scratch
 	_scratch_mkfs
-	echo "${meta_descr}" > "${populate_metadump_descr}"
 	case "${FSTYP}" in
 	"xfs")
 		_scratch_xfs_populate $@
 		_scratch_xfs_populate_check
-
-		local logdev=none
-		[ "$USE_EXTERNAL" = yes -a ! -z "$SCRATCH_LOGDEV" ] && \
-			logdev=$SCRATCH_LOGDEV
-
-		_xfs_metadump "$POPULATE_METADUMP" "$SCRATCH_DEV" "$logdev" \
-			compress -a -o
 		;;
 	"ext2"|"ext3"|"ext4")
 		_scratch_ext4_populate $@
 		_scratch_ext4_populate_check
-		_ext4_metadump "${SCRATCH_DEV}" "${POPULATE_METADUMP}" compress
 		;;
 	*)
 		_fail "Don't know how to populate a ${FSTYP} filesystem."
 		;;
 	esac
+
+	_scratch_populate_save_metadump "${POPULATE_METADUMP}" && \
+			echo "${meta_descr}" > "${populate_metadump_descr}"
 }
-- 
2.39.5