README.md

@@ -14,6 +14,7 @@ Btrfs snapshot managing bash script
 - Snapshots can be listed with `snapsh -l` or `snapsh --list`
 - Delete snapshots with the `-r` or `--remove` option. List snapshots first with `snapsh -l`, then delete snapshot with e.g. `snapsh -r 2`, where 2 is the number of the deletable snapshot in the `-l` listing. The list numbers always start from 1 and increment from there, so always check the number before deletion. Batch deletion might be implemented later.
 - Rollback to a snapshot with `snapsh --rollback NUMBER`, where NUMBER is the number listed in `snapsh -l`. The subvolume will be detected from the snapshot. E.g. `snapsh --rollback 14`. Script will ask to reboot system once done.
+  - Rollback renames your currently active subvolume to SUBVOLUME.backup, if you want these backups to be deleted automatically, copy the included `snapsh-post-rollback.service` to `/etc/systemd/system` and `systemctl enable snapsh-post-rollback.service`. It will check if `*.backup` subvolumes exist and delete them on every boot. This is recommended to be enabled, since rollbacks also take a "regular" readonly snapshot as `SUBVOLUME_backup_YYYY.MM.DD-hh:mm:ss`. The unit will be enabled automatically with the `--install` option which will be done later.
 - Snapshot type displayed in listing can be set with the `-t, --type` option. When used in conjunction with `-l | --list`, it will filter the results based on the type. E.g. `snapsh -l -t manual` will list all the snapshots with the type `manual`. Type can be one of `manual, auto, boot` or `backup`. Note that only `manual` and `backup` are implemented properly at this stage, but you can still use the other types as well.
 
 ### Planned features:

snapsh

@@ -16,16 +16,25 @@
 ## You should have received a copy of the GNU General Public License
 ## along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+printf "\n"     # Print an empty line for readability
+
 # Environment set up:
 
-TOPLEVEL="/root/btrfs-toplevel"
+# If config file exists, source it, otherwise use default values
-SNAPSHOTS_LOCATION="/root/btrfs-toplevel/snapshots"
+if [[ -e /etc/snapsh.conf ]]; then
+    . /etc/snapsh.conf
+else
+    TOPLEVEL="/root/btrfs-toplevel"                     # Mountpoint of subvolid=6
+    SNAPSHOTS_LOCATION="/root/btrfs-toplevel/snapshots" # Mountpoint of subvolume for snapshots
 
+    TIMESTAMP="$(date +%Y.%m.%d-%H.%M.%S)"              # Timestamp used in naming snapshots
+fi                                                      # (Not the one used in --list)
+
+## In case of problems, define the path to the 'btrfs' executable here
 BTRFS_EXECUTABLE=$(which btrfs)
-TIMESTAMP=$(date +%Y.%m.%d-%H:%M:%S)
-SUBVOLUME="root"
-DESCRIPTION=""
 
+SUBVOLUME="root"    # Default subvolume
+DESCRIPTION=""      # Description is blank unless set with the -d|--description option
 
 
 help() {
@@ -52,7 +61,7 @@ Options:
 snapshot() {
 
     EXIT_CODE=0
-    root_check
+    root_check          #Check that script is run with root privileges.
 
     # Check that the subvolume storing snapshots exists
     if [[ ! -d ${SNAPSHOTS_LOCATION} ]]; then
@@ -60,6 +69,7 @@ snapshot() {
         read -n 1 -p "y/n: "
         
         if [[ "${REPLY}" == "y" ]]; then
+            # Create subvolume defined with SNAPSHOTS_LOCATION
             ${BTRFS_EXECUTABLE} subvolume create ${SNAPSHOTS_LOCATION}
             unset ${REPLY}
         else
@@ -74,7 +84,7 @@ snapshot() {
         printf "Creating snapshot of subvolume ${SUBVOLUME} as ${SUBVOLUME}_snapshot_${TIMESTAMP}\n"
 
         # Create info file for listing snapshots
-        # Created first on the source subvolume, then deleted
+        # Created first on the source subvolume, then deleted from the source
         printf "DATE=\"$(date)\"
         SOURCE_SUBVOLUME=\"${SUBVOLUME}\"
         DESCRIPTION=\"${DESCRIPTION}\"
@@ -122,8 +132,11 @@ list() {
 
 remove() {
     root_check
+
+    # List snapshots in to array SNAPSHOTS
     SNAPSHOTS=(${SNAPSHOTS_LOCATION}/*/)
 
+    # Check that given NUMBER is a valid snapshot
     if [[ "${REMOVE_TARGET}" -gt "${#SNAPSHOTS[@]}" ]]; then
         printf "Snapshot number ${REMOVE_TARGET} does not exist.\n"
         exit 1
@@ -140,8 +153,8 @@ remove() {
     read -n 1
     if [[ "${REPLY}" == "y" ]]; then
         printf "\n"
-        ${BTRFS_EXECUTABLE} property set ${TARGET} ro false
+        ${BTRFS_EXECUTABLE} property set ${TARGET} ro false     # Set snapshot as read-write first
-        ${BTRFS_EXECUTABLE} subvolume delete ${TARGET}
+        ${BTRFS_EXECUTABLE} subvolume delete ${TARGET}          # Delete snapshot
         exit 0
     else
         printf "\nAborted by user.\n"
@@ -152,9 +165,10 @@ remove() {
 
 
 rollback() {
-    root_check
+    root_check      # Check root privileges
-    SNAPSHOTS=(${SNAPSHOTS_LOCATION}/*/)
+    SNAPSHOTS=(${SNAPSHOTS_LOCATION}/*/)    # List snapshots to array
 
+    # Check that NUBER to roll back to is a valid snapshot
     if [[ "${ROLLBACK_TARGET}" -gt "${#SNAPSHOTS[@]}" ]]; then
         printf "Snapshot number ${ROLLBACK_TARGET} does not exist.\n"
         exit 1
@@ -167,12 +181,12 @@ rollback() {
     TARGET=${SNAPSHOTS[${INDEX}]}
     . ${TARGET}/.snapsh
 
-    printf "You are about to roll back to snapshot ${ROLLBACK_TARGET}: ${DATE}, subvolume ${SOURCE_SUBVOLUME}, type ${TYPE}, ${DESCRIPTION}.\nAre you sure (yes/no)? "
+    printf "\nYou are about to roll back to snapshot ${ROLLBACK_TARGET}: ${DATE}, subvolume ${SOURCE_SUBVOLUME}, type ${TYPE}, ${DESCRIPTION}.\n\nAre you sure (yes/no)? "
     read
 
     if [[ "${REPLY}" == "yes" ]]; then
         unset ${REPLY}
-        printf "\nCreating a backup snapshot of ${SOURCE_SUBVOLUME}...\n"
+        printf "\nCreating a backup snapshot of ${SOURCE_SUBVOLUME}...\n\n"
         # Create info file
         printf "DATE=\"$(date)\"
         SOURCE_SUBVOLUME=\"${SOURCE_SUBVOLUME}\"
@@ -180,9 +194,12 @@ rollback() {
         TYPE=\"backup\"\n" > ${TOPLEVEL}/${SOURCE_SUBVOLUME}/.snapsh
 
         # Create backup snapshot
-        ${BTRFS_EXECUTABLE} subvolume snapshot -r ${TOPLEVEL}/${SUBVOLUME} ${SNAPSHOTS_LOCATION}/${SUBVOLUME}_snapshot_${TIMESTAMP}
+        printf "\nCreating snapshot of ${SUBVOLUME} as ${SNAPSHOTS_LOCATION}/${SUBVOLUME}_backup_${TIMESTAMP}...\n"
+        ${BTRFS_EXECUTABLE} subvolume snapshot -r ${TOPLEVEL}/${SUBVOLUME} ${SNAPSHOTS_LOCATION}/${SUBVOLUME}_backup_${TIMESTAMP}
         rm -f ${TOPLEVEL}/${SOURCE_SUBVOLUME}/.snapsh
 
+        printf "\n"
+
         # Rename current subvolume
         printf "Renaming ${SOURCE_SUBVOLUME} to ${SOURCE_SUBVOLUME}.backup...\n"
         mv ${TOPLEVEL}/${SOURCE_SUBVOLUME} ${TOPLEVEL}/${SOURCE_SUBVOLUME}.backup
@@ -190,13 +207,13 @@ rollback() {
         printf "Copying ${TARGET} to ${TOPLEVEL}/${SOURCE_SUBVOLUME}...\n"
         ${BTRFS_EXECUTABLE} subvolume snapshot ${TARGET} ${TOPLEVEL}/${SOURCE_SUBVOLUME}
 
-        printf "System needs to be restarted. Do you wish to do that now? (recommended!)? (y/n) "
+        printf "\nSystem needs to be restarted. Do you wish to do that now? (recommended!)? (y/n) "
         read -n 1
 
         if [[ "${REPLY}" == "y" ]]; then
             systemctl reboot & exit 0
         else
-            printf "\nPlease restart system as soon as possible. Any changes to subvolume ${SOURCE_SUBVOLUME} will not persist after rebooting.\n"
+            printf "\n\nPlease restart system as soon as possible. Any changes to subvolume ${SOURCE_SUBVOLUME} will not persist after rebooting.\n"
             exit 1
         fi
 
@@ -209,6 +226,34 @@ rollback() {
 
 
 
+post-rollback() {
+    ## This function is meant to be executed by the included systemd unit on every boot
+    ## Outputs to systemd-journal, use journalctl -t snapsh to check output
+
+    EXIT_CODE=0
+
+    shopt -s nullglob
+
+    echo "Checking for leftover subvolumes..." | systemd-cat -t snapsh
+
+    BACKUPS=("${TOPLEVEL}/*.backup/")
+
+    if [[ -n "$BACKUPS" ]]; then
+        for backup in ${TOPLEVEL}/*.backup/; do
+            echo "${backup} found" | systemd-cat -t snapsh
+            echo "Deleting ${backup}..." | systemd-cat -t snapsh
+            ${BTRFS_EXECUTABLE} subvolume delete ${backup} > /dev/null
+            let EXIT_CODE=${EXIT_CODE}+$?
+        done
+        exit ${EXIT_CODE}
+    else
+        echo "No leftovers found." | systemd-cat -t snapsh
+        exit 0
+    fi
+}
+
+
+
 # Check for root permissions
 root_check() {
     if [[ "$UID" -ne 0 ]]; then
@@ -227,7 +272,7 @@ fi
 
 
 # Options parsing:
-OPTIONS=$(getopt -a -n snapsh -o hs:d:lr:t: --long help,snapshot:,description:,list,remove:,rollback:,type: -- "$@")
+OPTIONS=$(getopt -a -n snapsh -o hs:d:lr:t: --long help,snapshot:,description:,list,remove:,rollback:,type:,post-rollback -- "$@")
 
 # Invalid options (getopt returns nonzero)
 if [[ "$?" -ne 0 ]]; then
@@ -237,6 +282,8 @@ if [[ "$?" -ne 0 ]]; then
 fi
 
 eval set -- "$OPTIONS"
+
+# Loop through options until -- is reached
 while true; do
     case "$1" in
 
@@ -274,6 +321,11 @@ while true; do
             shift 2
             ;;
 
+        --post-rollback)
+            post-rollback
+            shift
+            ;;
+        
         -t | --type)
             case "$2" in
                 manual)
@@ -285,7 +337,7 @@ while true; do
                 backup)
                     SET_TYPE="backup";;
                 *)
-                    printf "\nIncorrect type value.\n"
+                    printf "\nIncorrect TYPE value.\n"
                     exit 1;;
             esac
             shift 2

snapsh-post-rollback.service

@@ -0,0 +1,10 @@
+[Unit]
+Description=Remove leftover *.backup subvolumes
+
+[Service]
+Type=oneshot
+ExecStart=/usr/sbin/snapsh --post-rollback
+RemainAfterExit=yes
+
+[Install]
+WantedBy=default.target

snapsh.conf

@@ -0,0 +1,25 @@
+## Snapsh requires the toplevel (subvolid=5) mounted somewhere
+## You can define your mount point here.
+## Default: "/root/btrfs-toplevel"
+TOPLEVEL="/root/btrfs-toplevel"
+
+## You should create a subvolume for snapshots. Snapsh will do this
+## automatically, define the subvolume here. It is recommended
+## to have the subvolume directly under the btrfs root (id=5)
+## Use the full path
+## Default: "/root/"
+SNAPSHOTS_LOCATION="/root/btrfs-toplevel/snapshots"
+
+## Timestamp format. See 'date --help' for formatting options.
+## This will only be used for the name of the snapshot (=subvolume)
+## created. E.g. with default setting snapshots will be created as 
+## "/root/btrfs-toplevel/snapshots/root_snapshot_2020_07_31-01.59.23"
+## Default: $(date +%Y.%m.%d-%H.%M.%S)
+TIMESTAMP="$(date +%Y.%m.%d-%H.%M.%S)"
+
+
+
+## Experimental:
+## Define the list of subvolumes to be handled by snapsh here.
+## Defaut: (root home)
+SUBVOLUMES=(root home)