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dmsquash-live-root: Extend rd.live.overlay.readonly support 

Support the rd.live.overlay.readonly option for writable images,
such as rd.live.overlay=none and rd.writable.fsimg.
master
Frederick Grose 2017-03-11 18:53:35 -05:00
parent f1b65e92af
commit 3c6337f68e
2 changed files with 25 additions and 19 deletions
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3
dracut.cmdline.7.asc
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@ -954,7 +954,8 @@ Specifies a non-persistent overlay size in MiB. The default is _32768_.


**rd.live.overlay.readonly=**1:: **rd.live.overlay.readonly=**1::
Specifies a non-persistent, writable snapshot overlay to be stacked over a Specifies a non-persistent, writable snapshot overlay to be stacked over a
read-only snapshot of the root filesystem, `/dev/mapper/live-ro`. read-only snapshot of the root filesystem, `/dev/mapper/live-ro`, or a read-
only loop device of a writable `rootfs.img`.


**rd.live.overlay.reset=**1:: **rd.live.overlay.reset=**1::
Specifies that a persistent overlay should be reset on boot. All root Specifies that a persistent overlay should be reset on boot. All root

41
modules.d/90dmsquash-live/dmsquash-live-root.sh
View File

@ -90,7 +90,6 @@ do_live_overlay() {
# create a sparse file for the overlay # create a sparse file for the overlay
# overlay: if non-ram overlay searching is desired, do it, # overlay: if non-ram overlay searching is desired, do it,
# otherwise, create traditional overlay in ram # otherwise, create traditional overlay in ram
OVERLAY_LOOPDEV=$( losetup -f )


l=$(blkid -s LABEL -o value $livedev) || l="" l=$(blkid -s LABEL -o value $livedev) || l=""
u=$(blkid -s UUID -o value $livedev) || u="" u=$(blkid -s UUID -o value $livedev) || u=""
@ -108,14 +107,14 @@ do_live_overlay() {
devspec=$( echo $overlay | sed -e 's/:.*$//' ) devspec=$( echo $overlay | sed -e 's/:.*$//' )


# need to know where to look for the overlay # need to know where to look for the overlay
setup="" if [ -z "$setup" -a -n "$devspec" -a -n "$pathspec" -a -n "$overlay" ]; then
if [ -n "$devspec" -a -n "$pathspec" -a -n "$overlay" ]; then
mkdir -m 0755 /run/initramfs/overlayfs mkdir -m 0755 /run/initramfs/overlayfs
opt='' opt=''
[ -n "$readonly_overlay" ] && opt=-r [ -n "$readonly_overlay" ] && opt=-r
mount -n -t auto $devspec /run/initramfs/overlayfs || : mount -n -t auto $devspec /run/initramfs/overlayfs || :
if [ -f /run/initramfs/overlayfs$pathspec -a -w /run/initramfs/overlayfs$pathspec ]; then if [ -f /run/initramfs/overlayfs$pathspec -a -w /run/initramfs/overlayfs$pathspec ]; then
losetup $opt $OVERLAY_LOOPDEV /run/initramfs/overlayfs$pathspec OVERLAY_LOOPDEV=$(losetup -f --show $opt /run/initramfs/overlayfs$pathspec)
over=$OVERLAY_LOOPDEV
umount -l /run/initramfs/overlayfs || : umount -l /run/initramfs/overlayfs || :
oltype=$(det_img_fs $OVERLAY_LOOPDEV) oltype=$(det_img_fs $OVERLAY_LOOPDEV)
if [ -z "$oltype" ] || [ "$oltype" = DM_snapshot_cow ]; then if [ -z "$oltype" ] || [ "$oltype" = DM_snapshot_cow ]; then
@ -197,24 +196,22 @@ do_live_overlay() {
else else
dd if=/dev/null of=/overlay bs=1024 count=1 seek=$((overlay_size*1024)) 2> /dev/null dd if=/dev/null of=/overlay bs=1024 count=1 seek=$((overlay_size*1024)) 2> /dev/null
if [ -n "$setup" -a -n "$readonly_overlay" ]; then if [ -n "$setup" -a -n "$readonly_overlay" ]; then
RO_OVERLAY_LOOPDEV=$( losetup -f ) RO_OVERLAY_LOOPDEV=$(losetup -f --show /overlay)
losetup $RO_OVERLAY_LOOPDEV /overlay over=$RO_OVERLAY_LOOPDEV
else else
losetup $OVERLAY_LOOPDEV /overlay OVERLAY_LOOPDEV=$(losetup -f --show /overlay)
over=$OVERLAY_LOOPDEV
fi fi
fi fi
fi fi


# set up the snapshot # set up the snapshot
sz=$(blockdev --getsz $BASE_LOOPDEV)
if [ -z "$overlayfs" ]; then if [ -z "$overlayfs" ]; then
if [ -n "$readonly_overlay" ]; then if [ -n "$readonly_overlay" ] && [ -n "$OVERLAY_LOOPDEV" ]; then
echo 0 $sz snapshot $BASE_LOOPDEV $OVERLAY_LOOPDEV P 8 | dmsetup create --readonly live-ro echo 0 $sz snapshot $BASE_LOOPDEV $OVERLAY_LOOPDEV P 8 | dmsetup create --readonly live-ro
base="/dev/mapper/live-ro" base="/dev/mapper/live-ro"
over=$RO_OVERLAY_LOOPDEV
else else
base=$BASE_LOOPDEV base=$BASE_LOOPDEV
over=$OVERLAY_LOOPDEV
fi fi
fi fi


@ -301,8 +298,6 @@ else
fi fi


if [ -n "$FSIMG" ] ; then if [ -n "$FSIMG" ] ; then
BASE_LOOPDEV=$( losetup -f )

if [ -n "$writable_fsimg" ] ; then if [ -n "$writable_fsimg" ] ; then
# mount the provided filesystem read/write # mount the provided filesystem read/write
echo "Unpacking live filesystem (may take some time)" > /dev/kmsg echo "Unpacking live filesystem (may take some time)" > /dev/kmsg
@ -314,14 +309,24 @@ if [ -n "$FSIMG" ] ; then
fi fi
FSIMG=/run/initramfs/fsimg/rootfs.img FSIMG=/run/initramfs/fsimg/rootfs.img
fi fi
if [ -n "$writable_fsimg" ] || [ -z "$SQUASHED" -a -n "$live_ram" -a -z "$overlayfs" ] || opt=-r
# For writable DM images...
if [ -z "$SQUASHED" -a -n "$live_ram" -a -z "$overlayfs" ] ||
[ -n "$writable_fsimg" ] ||
[ "$overlay" = none -o "$overlay" = None -o "$overlay" = NONE ]; then [ "$overlay" = none -o "$overlay" = None -o "$overlay" = NONE ]; then
losetup $BASE_LOOPDEV $FSIMG if [ -z "$readonly_overlay" ]; then
sz=$(blockdev --getsz $BASE_LOOPDEV) opt=''
setup=rw
else
setup=yes
fi
fi
BASE_LOOPDEV=$(losetup -f --show $opt $FSIMG)
sz=$(blockdev --getsz $BASE_LOOPDEV)
if [ "$setup" == rw ]; then
echo 0 $sz linear $BASE_LOOPDEV 0 | dmsetup create live-rw echo 0 $sz linear $BASE_LOOPDEV 0 | dmsetup create live-rw
else else
# Attach the filesystem read-only and add a DM snapshot or OverlayFS for writes. # Add a DM snapshot or OverlayFS for writes.
losetup -r $BASE_LOOPDEV $FSIMG
do_live_overlay do_live_overlay
fi fi
fi fi