[OE-core] [RFC] Hybrid live image?
Yong, Jonathan
jonathan.yong at intel.com
Fri Apr 28 02:09:42 UTC 2017
Hi,
Attached patch makes the init script attempt to find an writable image
to use with Overlay/AUFS, and probably does so poorly.
The idea is to eventually allow users to do a "RESET" option in case
they mess up the system. The underlying image can be something read-only
like cramfs or squashfs.
Any comments or suggestions?
-------------- next part --------------
diff --git a/meta/recipes-core/initrdscripts/files/init-live.sh b/meta/recipes-core/initrdscripts/files/init-live.sh
index 441b41c..35047c8 100644
--- a/meta/recipes-core/initrdscripts/files/init-live.sh
+++ b/meta/recipes-core/initrdscripts/files/init-live.sh
@@ -152,6 +152,25 @@ do
sleep 1
done
+try_rw_image() {
+ for i in /run/media/$ROOT_DISK/$ISOLINUX/${ROOT_IMAGE}.rw; do
+ if [ -w $i ]; then
+ mount -o rw,loop,noatime,sync $i /rootfs.rw
+ if [ "$?" -ne 0 ]; then
+ break
+ fi
+ touch /rootfs.rw/.rwtest 2>/dev/null
+ if [ "$?" -ne 0 ]; then
+ break
+ fi
+ rm /rootfs.rw/.rwtest
+ return
+ fi
+ done
+ umount /rootfs.rw
+ mount -t tmpfs -o rw,noatime,mode=755 tmpfs /rootfs.rw
+}
+
# Try to mount the root image read-write and then boot it up.
# This function distinguishes between a read-only image and a read-write image.
# In the former case (typically an iso), it tries to make a union mount if possible.
@@ -159,6 +178,7 @@ done
mount_and_boot() {
mkdir $ROOT_MOUNT
mknod /dev/loop0 b 7 0 2>/dev/null
+ mknod /dev/loop1 b 7 1 2>/dev/null
if ! mount -o rw,loop,noatime,nodiratime /run/media/$ROOT_DISK/$ISOLINUX/$ROOT_IMAGE $ROOT_MOUNT ; then
fatal "Could not mount rootfs image"
@@ -187,7 +207,7 @@ mount_and_boot() {
rm -rf /rootfs.ro /rootfs.rw
fatal "Could not move rootfs mount point"
else
- mount -t tmpfs -o rw,noatime,mode=755 tmpfs /rootfs.rw
+ try_rw_image
mkdir -p /rootfs.rw/upperdir /rootfs.rw/work
mount -t overlay overlay -o "lowerdir=/rootfs.ro,upperdir=/rootfs.rw/upperdir,workdir=/rootfs.rw/work" $ROOT_MOUNT
mkdir -p $ROOT_MOUNT/rootfs.ro $ROOT_MOUNT/rootfs.rw
@@ -201,7 +221,7 @@ mount_and_boot() {
rm -rf /rootfs.ro /rootfs.rw
fatal "Could not move rootfs mount point"
else
- mount -t tmpfs -o rw,noatime,mode=755 tmpfs /rootfs.rw
+ try_rw_image
mount -t aufs -o "dirs=/rootfs.rw=rw:/rootfs.ro=ro" aufs $ROOT_MOUNT
mkdir -p $ROOT_MOUNT/rootfs.ro $ROOT_MOUNT/rootfs.rw
mount --move /rootfs.ro $ROOT_MOUNT/rootfs.ro
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