Update fs.sh

tools/ceph/fs.sh

@@ -172,6 +172,11 @@ cmd_mount() {
         exit 1
     fi
 
+    if grep -qs "/mnt/ceph/storage " /proc/mounts; then
+        logError "The mount point is already in use: /mnt/ceph/storage. Try unmounting it first."
+        exit 1
+    fi
+
     sudo mount -t ceph -o name=webisstud,secretfile=/etc/ceph/ceph.client.webisstud.secret ceph.dw.webis.de:/storage /mnt/ceph/storage
 }
 
@@ -187,6 +192,11 @@ cmd_mount_rw() {
         exit 1
     fi
 
+    if grep -qs "/mnt/ceph/storage " /proc/mounts; then
+        logError "The mount point is already in use: /mnt/ceph/storage. Try unmounting it first."
+        exit 1
+    fi
+
     sudo mount -t ceph -o name=webis,secretfile=/etc/ceph/ceph.client.webis.secret ceph.dw.webis.de:/storage /mnt/ceph/storage
 }
 
@@ -197,6 +207,11 @@ cmd_umount() {
         exit 1
     fi
 
+    if ! grep -qs "/mnt/ceph/storage " /proc/mounts; then
+        logError "There is no mount at the mount point: /mnt/ceph/storage."
+        exit 1
+    fi
+
     sudo umount /mnt/ceph/storage
 }