Re: [Fedora-livecd-list] [PATCH] Boot a Live USB device as read-only after persisting some changes.

[Frederick Grose]

Harald has pushed the dracut part of this.  Is this acceptable for
Rawhide spins?

       --Fred

On Wed, Aug 14, 2013 at 4:42 PM,  <fgrose(a)gmail.com&gt; wrote:
>  From: Frederick Grose <fgrose(a)sugarlabs.org&gt;
>
>  commit a6cd70fc9df2d299ed4f347461c33e4824df62f0
>  Author: Frederick Grose <fgrose(a)sugarlabs.org&gt;
>
>      Enable read-only mounting of a persistent home.img filesystem.
>      Enable one to call for filesystem checking of home.img before
>      mounting on the next boot.
>
>  ---
>   fedora-live-base.ks | 24 ++++++++++++++++++++++--
>   1 file changed, 22 insertions(+), 2 deletions(-)
>
>  diff --git a/fedora-live-base.ks b/fedora-live-base.ks
>  index 6c76e96..0512f67 100644
>  --- a/fedora-live-base.ks
>  +++ b/fedora-live-base.ks
>  @@ -116,9 +116,13 @@ mountPersistentHome() {
>     elif [ ! -b "\$homedev" ]; then
>       loopdev=\`losetup -f\`
>       if [ "\${homedev##/run/initramfs/live}" != "\${homedev}" ];
> then
>  -      action "Remounting live store r/w" mount -o remount,rw
> /run/initramfs/live
>  +        if [ "\$liverw" = rw ]; then
>  +            action "Remounting live store r/w" mount -o remount,rw
> /run/initramfs/live
>  +        else
>  +            opts="-r"
>  +        fi
>       fi
>  -    losetup \$loopdev \$homedev
>  +    losetup \$opts \$loopdev \$homedev
>       homedev=\$loopdev
>     fi
>
>  @@ -130,6 +134,22 @@ mountPersistentHome() {
>       homedev=/dev/mapper/EncHome
>     fi
>
>  +  # If read-only is requested, prepare a non-persistent overlay and snapshot target.
>  +  if [ "\$opts" = "-r" ]; then
>  +    dd if=/dev/null of=/run/initramfs/overlayfs/home_overlay bs=1024 count=1
> seek=\$((512*1024)) 2> /dev/null
>  +    HOME_OVERLAY_LOOPDEV=\$(losetup -f)
>  +    losetup \$HOME_OVERLAY_LOOPDEV /run/initramfs/overlayfs/home_overlay
>  +    sz=\$(blockdev --getsz \$homedev)
>  +    echo 0 \$sz snapshot \$homedev \$HOME_OVERLAY_LOOPDEV N 8 | dmsetup create home-rw
>  +    homedev=/dev/mapper/home-rw
>  +  fi
>  +
>  +  # Check the filesystem, if requested.
>  +  if [ -e /forcehomefsck ]; then
>  +    e2fsck -f -y -v \$homedev || e2fsck -f -y \$homedev
>  +    rm /forcehomefsck
>  +  fi
>  +
>     # and finally do the mount
>     mount \$mountopts \$homedev /home
>     # if we have /home under what's passed for persistent home, then
>  --
>  1.8.3.1
>