fixed busy unmount problem

scripts/bootstrap-to-docker.sh

@@ -11,6 +11,9 @@ docker_user=${1:-${docker_user:-$(id -un)}}
 if test -f /etc/setup-debootstrap.conf; then
     . /etc/setup-debootstrap.conf
 fi
+if test -f ~/setup-debootstrap.conf; then
+    . ~/setup-debootstrap.conf
+fi
 
 tmpdir=${tmpdir:-"/var/tmp/chroots"}
 test -d "${tmpdir}" || mkdir -p "${tmpdir}"
@@ -139,6 +142,11 @@ for ((i=0; i<${#distros[@]}; ++i)); do
                 fi
             fi
             echo " ----    mount filesystems in ${tmpdir}/${distro}-${arch}" 1>&2
+            for x in proc sys dev; do
+                if mount | grep -q "${tmpdir}/${distro}-${arch}"/$x/; then
+                    umount -flr "${tmpdir}/${distro}-${arch}"/$x/
+                fi
+            done
             sudo mount -t proc proc "${tmpdir}/${distro}-${arch}"/proc/
             sudo mount -t sysfs sys "${tmpdir}/${distro}-${arch}"/sys/
             sudo mount -o bind /dev "${tmpdir}/${distro}-${arch}"/dev/
@@ -187,9 +195,11 @@ EOF1
             echo " ----    install ${instpkgs} to ${tmpdir}/${distro}-${arch}" 1>&2
             sudo chroot "${tmpdir}/${distro}-${arch}" apt-get -o Acquire::ForceIPv4=true install -y ${instpkgs}
             echo " ----    unmount filesystems in ${tmpdir}/${distro}-${arch}" 1>&2
-            sudo umount "${tmpdir}/${distro}-${arch}"/proc/
-            sudo umount "${tmpdir}/${distro}-${arch}"/sys/
-            sudo umount "${tmpdir}/${distro}-${arch}"/dev/
+            for x in proc sys dev; do
+                if mount | grep -q "${tmpdir}/${distro}-${arch}"/$x/; then
+                    umount -flr "${tmpdir}/${distro}-${arch}"/$x/
+                fi
+            done
             echo " ----    import ${tmpdir}/${distro}-${arch} to ${docker_user}/${type}:${distro}-${arch}" 1>&2
             cd "${tmpdir}/${distro}-${arch}"
             sudo tar c . | docker import - "${docker_user}/${type}:${distro}-${arch}"