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-rwxr-xr-xmeta/recipes-core/volatile-binds/files/mount-copybind30
1 files changed, 26 insertions, 4 deletions
diff --git a/meta/recipes-core/volatile-binds/files/mount-copybind b/meta/recipes-core/volatile-binds/files/mount-copybind
index 2aeaf84..fddf520 100755
--- a/meta/recipes-core/volatile-binds/files/mount-copybind
+++ b/meta/recipes-core/volatile-binds/files/mount-copybind
@@ -8,7 +8,10 @@ if [ $# -lt 2 ]; then
exit 1
fi
+# e.g. /var/volatile/lib
spec=$1
+
+# e.g. /var/lib
mountpoint=$2
if [ $# -gt 2 ]; then
@@ -20,15 +23,34 @@ fi
[ -n "$options" ] && options=",$options"
mkdir -p "${spec%/*}"
+
if [ -d "$mountpoint" ]; then
- if [ ! -d "$spec" ]; then
+
+ if [ -d "$spec" ]; then
+ specdir_existed=yes
+ else
+ specdir_existed=no
mkdir "$spec"
- cp -pPR "$mountpoint"/. "$spec/"
+ fi
+
+ # Fast version of calculating `dirname ${spec}`/.`basename ${spec}`-work
+ overlay_workdir="${spec%/*}/.${spec##*/}-work"
+ mkdir "${overlay_workdir}"
+
+ # Try to mount using overlay, which is must faster than copying files.
+ # If that fails, fall back to slower copy.
+ if ! mount -t overlay overlay -olowerdir="$mountpoint",upperdir="$spec",workdir="$overlay_workdir" "$mountpoint" > /dev/null 2>&1; then
+
+ if [ "$specdir_existed" != "yes" ]; then
+ cp -pPR "$mountpoint"/. "$spec/"
+ fi
+
+ mount -o "bind$options" "$spec" "$mountpoint"
fi
elif [ -f "$mountpoint" ]; then
if [ ! -f "$spec" ]; then
cp -pP "$mountpoint" "$spec"
fi
-fi
-mount -o "bind$options" "$spec" "$mountpoint"
+ mount -o "bind$options" "$spec" "$mountpoint"
+fi