Resolved some dmesg errors (#104)

try

@@ -159,7 +159,18 @@ make_overlay() {
     sandbox_dir="$1"
     lowerdirs="$2"
     overlay_mountpoint="$3"
-    mount -t overlay overlay -o userxattr -o "lowerdir=$lowerdirs,upperdir=$sandbox_dir/upperdir/$overlay_mountpoint,workdir=$sandbox_dir/workdir/$overlay_mountpoint" "$sandbox_dir/temproot/$overlay_mountpoint"
+    mount -t overlay overlay -o userxattr -o "lowerdir=$lowerdirs,upperdir=$sandbox_dir/upperdir/$overlay_mountpoint,workdir=$sandbox_dir/workdir/$overlay_mountpoint,index=off" "$sandbox_dir/temproot/$overlay_mountpoint"
+}
+
+check_fstype() {
+    mountpoint="$1"
+    fstype=$(stat -f -c %T "$mountpoint")
+
+    if [[ "$fstype" = "msdos" || "$fstype" = "exfat" || "$fstype" = "hfs" || "$fstype" = "hfs+" ]]; then
+      return 1
+    fi
+
+    return 0
 }
 
 
@@ -225,9 +236,18 @@ do
     esac
 
     # Try mounting everything normally
-    make_overlay "$SANDBOX_DIR" "$mountpoint" "$pure_mountpoint" 2>>"$try_mount_log"
+    # If the fstype is valid we mount everything
+
+    fs_fail_flag=0
+
+    if check_fstype "$pure_mountpoint"; then
+      make_overlay "$SANDBOX_DIR" "$mountpoint" "$pure_mountpoint" 2>>"$try_mount_log"
+    else
+      fs_fail_flag=1
+    fi
+
     # If mounting everything normally fails, we try using either using mergerfs or unionfs to mount them.
-    if [ "$?" -ne 0 ]
+    if [[ "$?" -ne 0 || "$fs_fail_flag" -ne 0 ]]
     then
         ## If the overlay failed, it means that there is a nested mount inside the target mount, e.g., both `/home` and `/home/user/mnt` are mounts.
         ## To address this, we use unionfs/mergerfs (they support the same functionality) to show all mounts under the target mount as normal directories.