diff --git a/coverage.sh b/coverage.sh
index 1eb87e4..c4765b6 100755
--- a/coverage.sh
+++ b/coverage.sh
@@ -126,8 +126,23 @@ if [ ! -e shared/hooks/eatmydata/customize.sh ] || [ hooks/eatmydata/customize.s
 		cp -a /usr/share/mmdebstrap/hooks/eatmydata/customize.sh shared/hooks/eatmydata/
 	fi
 fi
+mkdir -p shared/hooks/file-mirror-automount
+if [ ! -e shared/hooks/file-mirror-automount/setup00.sh ] || [ hooks/file-mirror-automount/setup00.sh -nt shared/hooks/file-mirror-automount/setup00.sh ]; then
+	if [ -e hooks/file-mirror-automount/setup00.sh ]; then
+		cp -a hooks/file-mirror-automount/setup00.sh shared/hooks/file-mirror-automount/
+	else
+		cp -a /usr/share/mmdebstrap/hooks/file-mirror-automount/setup00.sh shared/hooks/file-mirror-automount/
+	fi
+fi
+if [ ! -e shared/hooks/file-mirror-automount/customize00.sh ] || [ hooks/file-mirror-automount/customize00.sh -nt shared/hooks/file-mirror-automount/customize00.sh ]; then
+	if [ -e hooks/file-mirror-automount/customize00.sh ]; then
+		cp -a hooks/file-mirror-automount/customize00.sh shared/hooks/file-mirror-automount/
+	else
+		cp -a /usr/share/mmdebstrap/hooks/file-mirror-automount/customize00.sh shared/hooks/file-mirror-automount/
+	fi
+fi
 starttime=
-total=183
+total=184
 skipped=0
 runtests=0
 i=1
@@ -1556,6 +1571,27 @@ else
 	skipped=$((skipped+1))
 fi
 
+print_header "mode=$defaultmode,variant=apt: test file-mirror-automount hook"
+cat << END > shared/test.sh
+#!/bin/sh
+set -eu
+export LC_ALL=C.UTF-8
+if [ ! -e /mmdebstrap-testenv ]; then
+	echo "this test requires the cache directory to be mounted on /mnt and should only be run inside a container" >&2
+	exit 1
+fi
+$CMD --mode=$defaultmode --variant=apt --hook-dir=./hooks/file-mirror-automount --customize-hook='rmdir "\$1"/mnt/cache/debian/ "\$1"/mnt/cache' $DEFAULT_DIST /tmp/debian-chroot.tar "deb file:///mnt/cache/debian $DEFAULT_DIST main"
+tar -tf /tmp/debian-chroot.tar | sort | diff -u tar1.txt -
+rm /tmp/debian-chroot.tar
+END
+if [ "$HAVE_QEMU" = "yes" ]; then
+	./run_qemu.sh
+	runtests=$((runtests+1))
+else
+	echo "HAVE_QEMU != yes -- Skipping test..." >&2
+	skipped=$((skipped+1))
+fi
+
 print_header "mode=$defaultmode,variant=apt: mirror is deb..."
 cat << END > shared/test.sh
 #!/bin/sh
diff --git a/hooks/file-mirror-automount/customize00.sh b/hooks/file-mirror-automount/customize00.sh
new file mode 100755
index 0000000..8b181f8
--- /dev/null
+++ b/hooks/file-mirror-automount/customize00.sh
@@ -0,0 +1,26 @@
+#!/bin/sh
+
+set -eu
+
+if [ "$MMDEBSTRAP_VERBOSITY" -ge 3 ]; then
+	set -x
+fi
+
+rootdir="$1"
+
+if [ ! -e "$rootdir/run/mmdebstrap/file-mirror-automount" ]; then
+	exit 0
+fi
+
+xargsopts="--null --no-run-if-empty -I {} --max-args=1"
+
+echo "unmounting the following mountpoints:" >&2
+
+cat "$rootdir/run/mmdebstrap/file-mirror-automount" \
+	| xargs $xargsopts echo "    $rootdir/{}"
+
+cat "$rootdir/run/mmdebstrap/file-mirror-automount" \
+	| xargs $xargsopts umount "$rootdir/{}"
+
+rm "$rootdir/run/mmdebstrap/file-mirror-automount"
+rmdir --ignore-fail-on-non-empty "$rootdir/run/mmdebstrap"
diff --git a/hooks/file-mirror-automount/setup00.sh b/hooks/file-mirror-automount/setup00.sh
new file mode 100755
index 0000000..c1a3c96
--- /dev/null
+++ b/hooks/file-mirror-automount/setup00.sh
@@ -0,0 +1,20 @@
+#!/bin/sh
+
+set -eu
+
+if [ "$MMDEBSTRAP_VERBOSITY" -ge 3 ]; then
+	set -x
+fi
+
+rootdir="$1"
+
+env APT_CONFIG=$MMDEBSTRAP_APT_CONFIG apt-get indextargets --no-release-info \
+	| sed -ne 's/^Repo-URI: file:\/\+//p' \
+	| sort -u \
+	| while read path; do
+		echo "bind-mounting /$path into the chroot" >&2
+		mkdir -p "$rootdir/run/mmdebstrap"
+		mkdir -p "$rootdir/$path"
+		mount -o ro,bind "/$path" "$rootdir/$path"
+		printf '/%s\0' "$path" >> "$rootdir/run/mmdebstrap/file-mirror-automount"
+	done
diff --git a/mmdebstrap b/mmdebstrap
index d0d9ddb..2696348 100755
--- a/mmdebstrap
+++ b/mmdebstrap
@@ -2176,7 +2176,10 @@ sub run_download() {
         if (rindex $deb, $options->{root}, 0) {
             if (!-e "$options->{root}/$deb") {
                 error "package file $deb not accessible from chroot directory"
-                  . " -- use copy:// instead of file:// or a bind-mount";
+                  . " -- use copy:// instead of file:// or a bind-mount. You"
+                  . " can also try using --hook-dir=/usr/share/mmdebstrap/"
+                  . "hooks/file-mirror-automount to automatically create"
+                  . " the necessary bind-mounts.";
             }
             push @essential_pkgs, $deb;
             next;
@@ -6203,6 +6206,11 @@ architecture specific symlinks
 
     --hook-dir=/usr/share/mmdebstrap/hooks/merged-usr
 
+Example 4: Automatically mount all directories referenced by C<file://> mirrors
+into the chroot
+
+    --hook-dir=/usr/share/mmdebstrap/hooks/file-mirror-automount
+
 =item B<--skip>=I<stage>[,I<stage>,...]
 
 B<mmdebstrap> tries hard to implement sensible defaults and will try to stop
@@ -6899,6 +6907,24 @@ inside the chroot.
         --customize-hook='sync-out /var/cache/apt/archives ./cache' \
         unstable /dev/null
 
+Instead of copying potentially large amounts of data with B<sync-in> you can
+also use a bind-mount in combination with a C<file://> mirror to make packages
+from the outside available inside the chroot:
+
+    $ mmdebstrap --variant=apt --skip=essential/unlink \
+        --setup-hook='mkdir "$1/tmp/mirror"' \
+        --setup-hook='mount -o ro,bind /tmp/mirror "$1/tmp/mirror"' \
+        --customize-hook='sync-out /var/cache/apt/archives ./cache' \
+        --customize-hook='umount "$1/tmp/mirror"; rmdir "$1/tmp/mirror";' \
+        unstable /dev/null file:///tmp/mirror http://deb.debian.org/debian
+
+To automatically mount all directories referenced by C<file://> mirrors
+into the chroot you can use a hook:
+
+    $ mmdebstrap --variant=apt \
+        --hook-dir=/usr/share/mmdebstrap/hooks/file-mirror-automount \
+        unstable /dev/null file:///tmp/mirror1 file:///tmp/mirror2
+
 Create a system that can be used with docker:
 
     $ mmdebstrap unstable | sudo docker import - debian