Introduce Initialize_Last_SysTarget_Snapshot() function

This is in preparation for ZFS support.

diff --git a/bin/backup-script b/bin/backup-script
index b3a3bd8d6776d92c22b70486a32694eb56534e18..8da13700f2c790a323f4e5558588da531a6ae8ce 100755 (executable)
--- a/bin/backup-script
+++ b/bin/backup-script
@@ -182,6 +182,33 @@ DeleteSubvolume() {
        return 0
 }
 
+Initialize_Last_SysTarget_Snapshot() {
+       sys_target="$1"
+       unset last
+       unset snapshot
+
+       fs=$(GetFS "$sys_target")
+       case "$fs" in
+         "btrfs")
+               # Search directory of last generation, if any
+               last=$(ls -1d "$sys_target"/[0-9]* 2>/dev/null | sort -r | head -n1)
+               if [ -n "$last" ]; then
+                       if [ ! -d "$last" ]; then
+                               echo "Last snapshot \"$last\" seems not to be a directory!? \"$system\" skipped!"
+                               echo
+                               return 1
+                       fi
+               fi
+               sys_target="$sys_target/$(date +%Y%m%d-%H%M%S)"
+               snapshot="$sys_target"
+               ;;
+         *)
+               echo "Initialize_Last_SysTarget_Snapshot: Incompatible FS type \"$fs\" on \"$sys_target\"!"
+               return 1
+       esac
+       return 0
+}
+
 while [ $# -gt 0 ]; do
        case "$1" in
          "-n"|"--dry-run")
@@ -355,16 +382,7 @@ for f in $sys; do
                        echo; continue
                fi
 
-               # Search directory of last generation, if any
-               last=$(ls -1d "$sys_target"/[0-9]* 2>/dev/null | sort -r | head -n1)
-               if [ -n "$last" ]; then
-                       if [ ! -d "$last" ]; then
-                               echo "Last snapshot \"$last\" seems not to be a directory!? \"$system\" skipped!"
-                               echo; continue
-                       fi
-               fi
-               sys_target="$sys_target/$(date +%Y%m%d-%H%M%S)"
-               snapshot="$sys_target"
+               Initialize_Last_SysTarget_Snapshot "$sys_target" || continue
 
                if [ -n "$last" -a ! -e "$last/.stamp" ]; then
                        # Old backup directory without "stamp file", continue