1 files changed, 54 insertions, 5 deletions
diff --git a/meta/recipes-core/volatile-binds/files/mount-copybind b/meta/recipes-core/volatile-binds/files/mount-copybind
index 2aeaf84ddb..ddc4357615 100755
--- a/meta/recipes-core/volatile-binds/files/mount-copybind
+++ b/meta/recipes-core/volatile-binds/files/mount-copybind
@@ -2,13 +2,19 @@
 #
 # Perform a bind mount, copying existing files as we do so to ensure the
 # overlaid path has the necessary content.
+# If the target is a directory and overlayfs is available (and the environment
+# variable MOUNT_COPYBIND_AVOID_OVERLAYFS=1 is not set), then an overlay mount
+# will be attempted first.
 
 if [ $# -lt 2 ]; then
     echo >&2 "Usage: $0 spec mountpoint [OPTIONS]"
     exit 1
 fi
 
+# e.g. /var/volatile/lib
 spec=$1
+
+# e.g. /var/lib
 mountpoint=$2
 
 if [ $# -gt 2 ]; then
@@ -20,15 +26,58 @@ fi
 [ -n "$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/"
+        # If the $spec directory is created we need to take care that
+        # the selinux context is correct
+        if command -v selinuxenabled > /dev/null 2>&1; then
+            if selinuxenabled; then
+                restorecon "$spec"
+            fi
+        fi
+    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 command -v selinuxenabled > /dev/null 2>&1; then
+        if selinuxenabled; then
+            mountcontext=",rootcontext=$(matchpathcon -n "$mountpoint")"
+        fi
+    fi
+    if [ "$MOUNT_COPYBIND_AVOID_OVERLAYFS" = 1 ] || ! mount -t overlay overlay -olowerdir="$mountpoint",upperdir="$spec",workdir="$overlay_workdir""$mountcontext" "$mountpoint" > /dev/null 2>&1; then
+
+        if [ "$specdir_existed" != "yes" ]; then
+            cp -aPR "$mountpoint"/. "$spec/"
+        fi
+
+        mount -o "bind$options" "$spec" "$mountpoint"
+        # restore the selinux context.
+        if command -v selinuxenabled > /dev/null 2>&1; then
+            if selinuxenabled; then
+                restorecon -R "$mountpoint"
+            fi
+        fi
     fi
 elif [ -f "$mountpoint" ]; then
     if [ ! -f "$spec" ]; then
-        cp -pP "$mountpoint" "$spec"
+        cp -aP "$mountpoint" "$spec"
     fi
-fi
 
-mount -o "bind$options" "$spec" "$mountpoint"
+    mount -o "bind$options" "$spec" "$mountpoint"
+    # restore the selinux context.
+    if command -v selinuxenabled > /dev/null 2>&1; then
+        if selinuxenabled; then
+            restorecon -R "$mountpoint"
+        fi
+    fi
+fi