2 # overlayfs specific common functions.
6 # Export overlayfs xattrs and constant value
7 export OVL_XATTR_OPAQUE="trusted.overlay.opaque"
8 export OVL_XATTR_REDIRECT="trusted.overlay.redirect"
9 export OVL_XATTR_IMPURE="trusted.overlay.impure"
10 export OVL_XATTR_ORIGIN="trusted.overlay.origin"
11 export OVL_XATTR_NLINK="trusted.overlay.nlink"
12 export OVL_XATTR_UPPER="trusted.overlay.upper"
14 # helper function to do the actual overlayfs mount operation
22 $MOUNT_PROG -t overlay -o lowerdir=$lowerdir -o upperdir=$upperdir \
23 -o workdir=$workdir `_common_dev_mount_options $*`
26 # Mount with same options/mnt/dev of scratch mount, but optionally
27 # with different lower/upper/work dirs
28 _overlay_scratch_mount_dirs()
35 _overlay_mount_dirs $lowerdir $upperdir $workdir \
36 $* $OVL_BASE_SCRATCH_MNT $SCRATCH_MNT
43 mkdir -p $dir/$OVL_UPPER
44 mkdir -p $dir/$OVL_LOWER
45 mkdir -p $dir/$OVL_WORK
46 mkdir -p $dir/$OVL_MNT
49 # Given a base fs dir, set up overlay directories and mount on the given mnt.
50 # The dir is used as the mount device so it can be seen from df or mount
57 _supports_filetype $dir || _notrun "upper fs needs to support d_type"
61 _overlay_mount_dirs $dir/$OVL_LOWER $dir/$OVL_UPPER $dir/$OVL_WORK \
73 if [ -z "$dev" -o -z "$mnt" ] || \
74 _check_mounted_on $devname $dev $mntname $mnt; then
75 # no base fs or already mounted
77 elif [ $? -ne 1 ]; then
78 # base fs mounted but not on mount point
85 _overlay_base_test_mount()
87 _overlay_base_mount OVL_BASE_TEST_DEV OVL_BASE_TEST_DIR \
88 "$OVL_BASE_TEST_DEV" "$OVL_BASE_TEST_DIR" \
89 $TEST_FS_MOUNT_OPTS $SELINUX_MOUNT_OPTIONS
94 _overlay_base_test_mount && \
95 _overlay_mount $OVL_BASE_TEST_DIR $TEST_DIR $*
98 _overlay_base_scratch_mount()
100 _overlay_base_mount OVL_BASE_SCRATCH_DEV OVL_BASE_SCRATCH_MNT \
101 "$OVL_BASE_SCRATCH_DEV" "$OVL_BASE_SCRATCH_MNT" \
102 $OVL_BASE_MOUNT_OPTIONS $SELINUX_MOUNT_OPTIONS
105 _overlay_scratch_mount()
107 _overlay_base_scratch_mount && \
108 _overlay_mount $OVL_BASE_SCRATCH_MNT $SCRATCH_MNT $*
111 _overlay_base_unmount()
116 [ -n "$dev" -a -n "$mnt" ] || return 0
121 _overlay_test_unmount()
123 $UMOUNT_PROG $TEST_DIR
124 _overlay_base_unmount "$OVL_BASE_TEST_DEV" "$OVL_BASE_TEST_DIR"
127 _overlay_scratch_unmount()
129 $UMOUNT_PROG $SCRATCH_MNT
130 _overlay_base_unmount "$OVL_BASE_SCRATCH_DEV" "$OVL_BASE_SCRATCH_MNT"
133 # Check that a specific overlayfs feature is supported
134 __check_scratch_overlay_feature()
138 # overalyfs features (e.g. redirect_dir, index) are
139 # configurable from Kconfig (the build default), by module
140 # parameter (the system default) and per mount by mount
141 # option ${feature}=[on|off].
143 # If the module parameter does not exist then there is no
144 # point in checking the mount option.
145 local default=`_get_fs_module_param ${feature}`
146 [ "$default" = Y ] || [ "$default" = N ] || \
147 _notrun "feature '${feature}' not supported by ${FSTYP}"
149 # Check options to be sure. For example, Overlayfs will fallback to
150 # index=off if underlying fs does not support file handles.
151 # Overlayfs only displays mount option if it differs from the default.
152 # Overlayfs may enable the feature, but fallback to read-only mount.
153 ((( [ "$default" = N ] && _fs_options $SCRATCH_DEV | grep -q "${feature}=on" ) || \
154 ( [ "$default" = Y ] && ! _fs_options $SCRATCH_DEV | grep -q "${feature}=off" )) && \
155 touch $SCRATCH_MNT/foo 2>/dev/null ) || \
156 _notrun "${FSTYP} feature '${feature}' cannot be enabled on ${SCRATCH_DEV}"
159 # Require a set of overlayfs features
160 _require_scratch_overlay_features()
162 local features=( $* )
165 for feature in ${features[*]}; do
166 opts+=",${feature}=on"
169 _scratch_mkfs > /dev/null 2>&1
170 _try_scratch_mount -o $opts || \
171 _notrun "overlay options '$opts' cannot be enabled on ${SCRATCH_DEV}"
173 for feature in ${features[*]}; do
174 __check_scratch_overlay_feature ${feature}
180 # Helper function to check underlying dirs of overlay filesystem
188 [[ ! -x "$FSCK_OVERLAY_PROG" ]] && return 0
190 $FSCK_OVERLAY_PROG -o lowerdir=$lowerdir -o upperdir=$upperdir \
191 -o workdir=$workdir $*