{Create|Clone|Rename|Delete}Subvolume: Prepare for multiple FS

Currently only btrfs is supported, but support for ZFS is planned.
Introduce GetFS() function to detect the file system type.

diff --git a/bin/backup-script b/bin/backup-script
index 326046e0c4ef869286e1642fca6e41b1b01777d5..3131e3e6bb949a62fa8c7b91e98cd7f0f3f48e92 100755 (executable)
--- a/bin/backup-script
+++ b/bin/backup-script
@@ -95,30 +95,82 @@ ExecJob() {
        return $ret
 }
 
+GetFS() {
+       dir="$1"
+       while [ -n "$dir" ]; do
+               findmnt -fn -o FSTYPE --raw "$dir" 2>/dev/null; r=$?
+               if [ $r -eq 0 ]; then
+                       return 0
+               elif [ $r -eq 127 ]; then
+                       echo "UNKNOWN"
+                       return 1
+               fi
+               dir=$(dirname "$dir") || return 1
+       done
+}
+
 CreateSubvolume() {
        volume="$1"
 
-       btrfs subvolume create "$volume"
+       dir=$(dirname "$volume")
+       fs=$(GetFS "$dir")
+       case "$fs" in
+         "btrfs")
+               btrfs subvolume create "$volume"  >/dev/null || return 1
+               ;;
+         *)
+               echo "CreateSubvolume: Incompatible FS type \"$fs\" on \"$dir\"!"
+               return 9
+       esac
+       return 0
 }
 
 CloneSubvolume() {
        source="$1"
        volume="$2"
 
-       btrfs subvolume snapshot "$source" "$volume"
+       dir=$(dirname "source")
+       fs=$(GetFS "$source")
+       case "$fs" in
+         "btrfs")
+               btrfs subvolume snapshot "$source" "$volume"  >/dev/null || return 1
+               ;;
+         *)
+               echo "CloneSubvolume: Incompatible FS type \"$fs\" on \"$source\"!"
+               return 9
+       esac
+       return 0
 }
 
 RenameSubvolume() {
        source="$1"
        target="$2"
 
-       mv "$source" "$target"
+       fs=$(GetFS "$source")
+       case "$fs" in
+         "btrfs")
+               mv "$source" "$target" || return 1
+               ;;
+         *)
+               echo "RenameSubvolume: Incompatible FS type \"$fs\" on \"$source\"!"
+               return 9
+       esac
+       return 0
 }
 
 DeleteSubvolume() {
        volume="$1"
 
-       btrfs subvolume delete "$volume"
+       fs=$(GetFS "$source")
+       case "$fs" in
+         "btrfs")
+               btrfs subvolume delete "$volume" >/dev/null || return 1
+               ;;
+         *)
+               echo "DeleteSubvolume: Incompatible FS type \"$fs\" on \"$volume\"!"
+               return 9
+       esac
+       return 0
 }
 
 while [ $# -gt 0 ]; do
@@ -282,7 +334,7 @@ for f in $sys; do
                if [ -n "$last" -a ! -e "$last/.stamp" ]; then
                        # Old backup directory without "stamp file", continue
                        echo "Found incomplete snapshot in \"$last\", reusing and renaming it ..."
-                       RenameSubvolume "$last" "$sys_target" >/dev/null 2>&1
+                       RenameSubvolume "$last" "$sys_target"
                        if [ $? -ne 0 ]; then
                                echo "Failed to rename last snapshot \"$last\" to \"$sys_target\"!? \"$system\" skipped!"
                                echo; continue
@@ -291,8 +343,7 @@ for f in $sys; do
                        # Old backup directory found, create new snapshot
                        echo "Found last snapshot in \"$last\"."
                        if [ "$DRYRUN" -eq 0 ]; then
-                               CloneSubvolume \
-                                 "$last" "$sys_target" >/dev/null 2>&1; r=$?
+                               CloneSubvolume "$last" "$sys_target"; r=$?
                                if [ $r -ne 0 ]; then
                                        echo "Can't create snapshot \"$sys_target\" of \"$last\", code $r!? \"$system\" skipped!"
                                        echo; continue
@@ -304,8 +355,7 @@ for f in $sys; do
                else
                        # No old backup found, create new subvolume
                        if [ "$DRYRUN" -eq 0 ]; then
-                               CreateSubvolume \
-                                 "$sys_target" >/dev/null 2>&1; r=$?
+                               CreateSubvolume "$sys_target"; r=$?
                                if [ $r -ne 0 ]; then
                                        echo "Can't create subvolume \"$sys_target\", code $r!? \"$system\" skipped!"
                                        echo; continue
@@ -405,10 +455,9 @@ for f in $sys; do
                                 | cut -d':' -f2- | cut -d. -f1)
                                echo "Removing backup from" $last "..."
                                if [ "$DRYRUN" -eq 0 ]; then
-                                       DeleteSubvolume \
-                                        "$dir" >/dev/null 2>&1
+                                       DeleteSubvolume "$dir"
                                        [ $? -eq 0 ] || \
-                                        echo "Failed to delete \"$dir\"!"
+                                         echo "Failed to delete \"$dir\"!"
                                fi
                        done
                        echo -n "Clean up finished: "; date