diff --git a/btrfs-snapshots.sh b/btrfs-snapshots.sh
index d54f601..008dfaf 100755
--- a/btrfs-snapshots.sh
+++ b/btrfs-snapshots.sh
@@ -49,34 +49,46 @@ EOF
     fi
     shift
 done
-
-BTRFS_VOLUMES=${BTRFS_VOLUMES:-$(awk '!/^#/ && $3=="btrfs" {print $2}' /etc/fstab)}
-TMP_MNT=${TMP_MNT:-/var/tmp/btrfs-backup}
+if test -n "${vols[*]}"; then
+    BTRFS_VOLUMES="${vols[*]}"
+fi
 
 test -d "${TMP_MNT}" || mkdir -p "${TMP_MNT}"
 for fs in ${BTRFS_VOLUMES}; do
     device=$(mount | awk '$3=="'$fs'" && $5=="btrfs" {print $1}')
     subvol=$(mount | awk '$3=="'$fs'" && $5=="btrfs" {split(substr($6, 2, length($6)-2), res, ","); for (r in res) {if (res[r]~/^subvol=/) {sub(/^subvol=/,"" , res[r]); print res[r]}}}')
     if test -n "$subvol"; then
-        name=${subvol}
+        if test "$subvol" = "/@"; then
+            name=${subvol}
+        else
+            name=${subvol}-
+        fi
     else
         if test "$fs" = "/"; then
-            name="@root"
+            name="/"
         else
             name=${fs#/}
             name=${name%/}
-            name=${name//\//-}
+            name=/${name//\//-}-
         fi
     fi
-    target="${name}-snapshot-$(date +%Y-%m-%d-%H-%M)"
-    if test $dryrun -eq 1; then
-        echo btrfs subvolume snapshot "${TMP_MNT}${subvol}" "${TMP_MNT}/${target}"
-    else
-        if mount | grep -q " on $TMP_MNT type "; then
+    target="${name}snapshot-$(date +%Y-%m-%d-%H-%M)"
+    if test -n "$device"; then
+        if test $dryrun -eq 1; then
+            echo -e "→ \e[1mbackup ${subvol:+subvol $subvol of }$fs on $device\e[0m"
+            echo " " mount "$device" "$TMP_MNT"
+            echo " " btrfs subvolume snapshot "${TMP_MNT}${subvol}" "${TMP_MNT}${target}"
+            echo " " umount "$TMP_MNT"
+        else
+            if mount | grep -q " on $TMP_MNT type "; then
+                sudo umount "$TMP_MNT"
+            fi
+            sudo mount "$device" "$TMP_MNT"
+            sudo btrfs subvolume snapshot "${TMP_MNT}${subvol}" "${TMP_MNT}${target}"
             sudo umount "$TMP_MNT"
         fi
-        sudo mount "$device" "$TMP_MNT"
-        sudo btrfs subvolume snapshot "${TMP_MNT}${subvol}" "${TMP_MNT}/${target}"
-        sudo umount "$TMP_MNT"
+    else
+        echo "ERROR: no device found for $fs" 1>&2
+        exit 2
     fi
 done