minor btrfs backup fixes

Signed-off-by: kitzman <kitzman@disroot.org>

scripts/generic_btrfs_backups/btrfs_backups.sh

@@ -4,7 +4,10 @@ set -e
 
 backup_filename=".snapshot-$(date -I)"
 
+#
 # runtime
+#
+
 progname=$(basename $0)
 
 if [[ "$progname" != backup\.* ]]; then
@@ -14,7 +17,10 @@ fi
 
 jobname=${progname:7}
 
+#
 # configuration
+#
+
 . /etc/conf.d/backup.$jobname
 
 logger_ident="${logger_ident:-backups}"
@@ -29,7 +35,9 @@ if [ -z "$source_storage_path" ]; then
     echo "source_storage_path not set!"
 fi
 
+#
 # utils & sanity checks
+#
 
 function log() { echo $@; logger -t $logger_ident $@; }
 
@@ -55,13 +63,15 @@ fi
 
 log "removing old backups from $target_backups_path"
 
-for backup_vol in $(find $target_backups_path -maxdepth 1 -type d \
+for backup_vol_path in $(find $target_backups_path -maxdepth 1 -type d \
 			 -name ".snapshot*" | \
-			sort | head -n $backup_retency); do
-    
+			sort | head -n "-$backup_retency"); do
+
+    backup_vol=$(basename $backup_vol_path)
+
     log "removing $backup_vol"
     backup_volid=$(btrfs sub list $target_backups_path | \
-		       grep $backup_vol | awk '{print $1}')
+		       grep $backup_vol | awk '{print $2}')
     btrfs sub del $target_backups_path/$backup_vol
 
     qgroup_id="0/$backup_volid"
@@ -100,7 +110,7 @@ fi
 if [ ! -z "$backup_qgroupid" ]; then
     log "assigning qgroup $backup_qgroupid"
     backup_volid=$(btrfs sub list $target_backups_path | \
-		       grep $backup_filename | awk '{print $1}')
+		       grep $backup_filename | awk '{print $2}')
 
     btrfs qgroup assign --rescan "0/$backup_volid" "$backup_qgroupid" $target_backups_path
 fi
@@ -112,7 +122,15 @@ fi
 log "removing old backups from $source_storage_path"
 
 if [ ! -z "$parent_backup" ]; then
+    log "removing $source_storage_path/$parent_backup"
+
+    backup_volid=$(btrfs sub list $target_backups_path | \
+		       grep $backup_vol | awk '{print $2}')
     btrfs subvolume delete $source_storage_path/$parent_backup
+
+    qgroup_id="0/$backup_volid"
+
+    btrfs qgroup destroy $qgroup_id || log "could not find qgroup $qgroup_id"
 fi
 
 #