Merge branch 'overlayfs' of https://github.com/FGrose/dracut into FGrose-overlayfs

dracut.cmdline.7.asc

@@ -820,10 +820,12 @@ only filesystem from the SquashFS and apply a writable device-mapper snapshot
 over the read only filesystem.  Using this method ensures a relatively fast
 boot and lower RAM usage. Users **must be careful** to avoid writing too many
 blocks to the snapshot volume.  Once the blocks of the snapshot overlay are
-exhausted, the root filesystem becomes unusable and requires a reboot.  A
-persistent overlay is marked Invalid, and requires a difficult recovery.
-Non-persistent overlays default to 512 MiB in RAM, but the size can be adjusted
-with the **rd.live.overlay.size=** kernel command line option.
+exhausted, the root filesystem becomes read only and may cause application
+failures.  The overlay file is marked 'Overflow', and a difficult recovery is
+required to repair and enlarge the overlay offline.  Non-persistent overlays
+are sparse files in RAM that only consume content space as required blocks are
+allocated.  They default to an apparent size of 32 GiB in RAM.  The size can be
+adjusted with the **rd.live.overlay.size=** kernel command line option.
 +
 The filesystem structure is expected to be:
 +
@@ -832,7 +834,7 @@ The filesystem structure is expected to be:
 squashfs.img          |  Squashfs from LiveCD .iso downloaded via network
    !(mount)
    /LiveOS
-       |- ext3fs.img  |  Filesystem image to mount read-only
+       |- rootfs.img  |  Filesystem image to mount read-only
             !(mount)
             /bin      |  Live filesystem
             /boot     |
@@ -854,7 +856,7 @@ of the root filesystem.
 Uncompressed live filesystem image:::
 When the live system was installed with the '--skipcompress' option of the
 __livecd-iso-to-disk__ installation script for Live USB devices, the root
-filesystem image, `ext3fs.img`, is expanded on installation and no SquashFS
+filesystem image, `rootfs.img`, is expanded on installation and no SquashFS
 is involved during boot.
 +
 - If **rd.live.ram=1** is used in this situation, the full, uncompressed
@@ -919,8 +921,8 @@ root=live:torrent://example.com/liveboot.img.torrent
 Enables debug output from the live boot process.
 
 **rd.live.dir=**__<path>__::
-Specifies the directory within the squashfs where the ext3fs.img or rootfs.img
-can be found.  By default, this is __LiveOS__.
+Specifies the directory within the boot device where the squashfs.img or
+rootfs.img can be found.  By default, this is __LiveOS__.
 
 **rd.live.squashimg=**__<filename of SquashFS image>__::
 Specifies the filename for a SquashFS image of the root filesystem.
@@ -938,6 +940,8 @@ used to persist the changes made to the device specified by the
 **root=live:__<url>__** option.
 - _none_ specifies no overlay when an uncompressed live root filesystem is
 available.
+If a persistent overlay is detected at the standard LiveOS path, the overlay &
+overlay type detected (whether Device-mapper or OverlayFS) will be used.
 +
 [listing]
 .Example
@@ -946,11 +950,12 @@ rd.live.overlay=/dev/sdb1:persistent-overlay.img
 --
 
 **rd.live.overlay.size=**__<size_MiB>__::
-Specifies a non-persistent overlay size in MiB.  The default is _512_.
+Specifies a non-persistent overlay size in MiB.  The default is _32768_.
 
 **rd.live.overlay.readonly=**1::
 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::
 Specifies that a persistent overlay should be reset on boot.  All root
@@ -963,6 +968,28 @@ blocks that are not claimed by the filesystem. In this use case, this means
 that memory is given back to the kernel when the filesystem does not claim it
 anymore.
 
+**rd.live.overlay.overlayfs=**1::
+Enables the use of the **OverlayFS** kernel module, if available, to provide a
+copy-on-write union directory for the root filesystem.  OverlayFS overlays are
+directories of the files that have changed on the read-only base (lower)
+filesystem.  The root filesystem is provided through a special overlay type
+mount that merges the lower and upper directories.  If an OverlayFS upper
+directory is not present on the boot device, a tmpfs directory will be created
+at /run/overlayfs to provide temporary storage.  Persistent storage can be
+provided on vfat or msdos formatted devices by supplying the OverlayFS upper
+directory within an embedded filesystem that supports the creation of trusted.*
+extended attributes and provides a valid d_type in readdir responses, such as
+with ext4 and xfs.  On non-vfat-formatted devices, a persistent OverlayFS
+overlay can extend the available root filesystem storage up to the capacity of
+the LiveOS device.
+
+If a persistent overlay is detected at the standard LiveOS path, the overlay &
+overlay type detected (whether OverlayFS or Device-mapper) will be used.
+
+The **rd.live.overlay.readonly** option, which allows a persistent overlayfs to
+be mounted read only through a higher level transient overlay directory, has
+been implemented through the multiple lower layers feature of OverlayFS.
+
 
 Plymouth Boot Splash
 ~~~~~~~~~~~~~~~~~~~~

modules.d/90dm/dm-shutdown.sh

@@ -14,7 +14,8 @@ _do_dm_shutdown() {
     return $ret
 }
 
-if command -v dmsetup >/dev/null; then
+if command -v dmsetup >/dev/null &&
+    [ "x$(dmsetup status)" != "xNo devices found" ]; then
     _do_dm_shutdown $1
 else
     :

modules.d/90dmsquash-live/apply-live-updates.sh

@@ -1,6 +1,6 @@
 #!/bin/sh
 
-if [ -b /dev/mapper/live-rw ] && [ -d /run/initramfs/live/updates -o -d /updates ]; then
+if [ -L /run/rootfsbase ] && [ -d /run/initramfs/live/updates -o -d /updates ]; then
     info "Applying updates to live image..."
     mount -o bind /run $NEWROOT/run
     # avoid overwriting symlinks (e.g. /lib -> /usr/lib) with directories

modules.d/90dmsquash-live/dmsquash-generator.sh

@@ -52,21 +52,30 @@ esac
 
 GENERATOR_DIR="$2"
 [ -z "$GENERATOR_DIR" ] && exit 1
-
 [ -d "$GENERATOR_DIR" ] || mkdir "$GENERATOR_DIR"
 
+getargbool 0 rd.live.overlay.overlayfs && overlayfs="yes"
+[ -e /xor_overlayfs ] && xor_overlayfs="yes"
 ROOTFLAGS="$(getarg rootflags)"
 {
     echo "[Unit]"
     echo "Before=initrd-root-fs.target"
     echo "[Mount]"
     echo "Where=/sysroot"
-    echo "What=/dev/mapper/live-rw"
-    [ -n "$ROOTFLAGS" ] && echo "Options=${ROOTFLAGS}"
+    if [ "$overlayfs$xor_overlayfs" = "yes" ]; then
+        echo "What=LiveOS_rootfs"
+        echo "Options=${ROOTFLAGS},lowerdir=/run/rootfsbase,upperdir=/run/overlayfs,workdir=/run/ovlwork"
+        echo "Type=overlay"
+        _dev=LiveOS_rootfs
+    else
+        echo "What=/dev/mapper/live-rw"
+        [ -n "$ROOTFLAGS" ] && echo "Options=${ROOTFLAGS}"
+        _dev=dev-mapper-live\x2drw
+    fi
 } > "$GENERATOR_DIR"/sysroot.mount
 
-mkdir -p "$GENERATOR_DIR/dev-mapper-live\x2drw.device.d"
+mkdir -p "$GENERATOR_DIR/$_dev.device.d"
 {
     echo "[Unit]"
     echo "JobTimeoutSec=3000"
-} > "$GENERATOR_DIR/dev-mapper-live\x2drw.device.d/timeout.conf"
+} > "$GENERATOR_DIR/$_dev.device.d/timeout.conf"

modules.d/90dmsquash-live/dmsquash-live-root.sh

@@ -28,9 +28,10 @@ getargbool 0 rd.live.overlay.readonly -d -y readonly_overlay && readonly_overlay
 overlay=$(getarg rd.live.overlay -d overlay)
 getargbool 0 rd.writable.fsimg -d -y writable_fsimg && writable_fsimg="yes"
 overlay_size=$(getarg rd.live.overlay.size=)
-[ -z "$overlay_size" ] && overlay_size=512
+[ -z "$overlay_size" ] && overlay_size=32768
 
 getargbool 0 rd.live.overlay.thin && thin_snapshot="yes"
+getargbool 0 rd.live.overlay.overlayfs && overlayfs="yes"
 
 # CD/DVD media check
 [ -b $livedev ] && fs=$(blkid -s TYPE -o value $livedev)
@@ -89,7 +90,6 @@ do_live_overlay() {
     # create a sparse file for the overlay
     # overlay: if non-ram overlay searching is desired, do it,
     #              otherwise, create traditional overlay in ram
-    OVERLAY_LOOPDEV=$( losetup -f )
 
     l=$(blkid -s LABEL -o value $livedev) || l=""
     u=$(blkid -s UUID -o value $livedev) || u=""
@@ -107,51 +107,117 @@ do_live_overlay() {
     devspec=$( echo $overlay | sed -e 's/:.*$//' )
 
     # need to know where to look for the overlay
-    setup=""
-    if [ -n "$devspec" -a -n "$pathspec" -a -n "$overlay" ]; then
+    if [ -z "$setup" -a -n "$devspec" -a -n "$pathspec" -a -n "$overlay" ]; then
         mkdir -m 0755 /run/initramfs/overlayfs
+        opt=''
+        [ -n "$readonly_overlay" ] && opt=-r
         mount -n -t auto $devspec /run/initramfs/overlayfs || :
         if [ -f /run/initramfs/overlayfs$pathspec -a -w /run/initramfs/overlayfs$pathspec ]; then
-            losetup $OVERLAY_LOOPDEV /run/initramfs/overlayfs$pathspec
-            if [ -n "$reset_overlay" ]; then
-                dd if=/dev/zero of=$OVERLAY_LOOPDEV bs=64k count=1 conv=fsync 2>/dev/null
+            OVERLAY_LOOPDEV=$(losetup -f --show $opt /run/initramfs/overlayfs$pathspec)
+            over=$OVERLAY_LOOPDEV
+            umount -l /run/initramfs/overlayfs || :
+            oltype=$(det_img_fs $OVERLAY_LOOPDEV)
+            if [ -z "$oltype" ] || [ "$oltype" = DM_snapshot_cow ]; then
+                if [ -n "$reset_overlay" ]; then
+                    info "Resetting the Device-mapper overlay."
+                    dd if=/dev/zero of=$OVERLAY_LOOPDEV bs=64k count=1 conv=fsync 2>/dev/null
+                fi
+                if [ -n "$overlayfs" ]; then
+                    unset -v overlayfs
+                    [ -n "$DRACUT_SYSTEMD" ] && reloadsysrootmountunit="yes"
+                fi
+                setup="yes"
+            else
+                mount -n -t $oltype $opt $OVERLAY_LOOPDEV /run/initramfs/overlayfs
+                if [ -d /run/initramfs/overlayfs/overlayfs ] &&
+                    [ -d /run/initramfs/overlayfs/ovlwork ]; then
+                    ln -s /run/initramfs/overlayfs/overlayfs /run/overlayfs$opt
+                    ln -s /run/initramfs/overlayfs/ovlwork /run/ovlwork$opt
+                    if [ -z "$overlayfs" ]; then
+                        overlayfs="yes"
+                        [ -n "$DRACUT_SYSTEMD" ] && reloadsysrootmountunit="yes"
+                    fi
+                    setup="yes"
+                fi
+            fi
+        elif [ -d /run/initramfs/overlayfs$pathspec ] &&
+            [ -d /run/initramfs/overlayfs$pathspec/../ovlwork ]; then
+            ln -s /run/initramfs/overlayfs$pathspec /run/overlayfs$opt
+            ln -s /run/initramfs/overlayfs$pathspec/../ovlwork /run/ovlwork$opt
+            if [ -z "$overlayfs" ]; then
+                overlayfs="yes"
+                [ -n "$DRACUT_SYSTEMD" ] && reloadsysrootmountunit="yes"
             fi
             setup="yes"
         fi
-        umount -l /run/initramfs/overlayfs || :
+    fi
+    if [ -n "$overlayfs" ]; then
+        modprobe overlay
+        if [ $? != 0 ]; then
+            m='OverlayFS is not available; using temporary Device-mapper overlay.'
+            unset -v overlayfs setup
+            [ -n "$reloadsysrootmountunit" ] && unset -v reloadsysrootmountunit
+        fi
     fi
 
     if [ -z "$setup" -o -n "$readonly_overlay" ]; then
         if [ -n "$setup" ]; then
             warn "Using temporary overlay."
         elif [ -n "$devspec" -a -n "$pathspec" ]; then
-            warn "Unable to find persistent overlay; using temporary"
-            sleep 5
+            [ -z "$m" ] &&
+                m='  Unable to find a persistent overlay; using a temporary one.'
+            m=($'\n' "$m" $'\n'
+               '     All root filesystem changes will be lost on shutdown.'
+               $'\n' '        Press any key to continue')
+            echo -e "\n\n\n${m[*]}\n\n\n" > /dev/kmsg
+            if [ -n "$DRACUT_SYSTEMD" ]; then
+                if plymouth --ping ; then
+                    if getargbool 0 rhgb || getargbool 0 splash ; then
+                        m[0]='>>>'$'\n''>>>'$'\n''>>>'$'\n\n'
+                        m[5]=$'\n''<<<'$'\n''<<<'$'\n''<<<'
+                        plymouth display-message --text="${m[*]}"
+                    else
+                        plymouth ask-question --prompt="${m[*]}" --command=true
+                    fi
+                else
+                    m[0]='>>>'
+                    m[5]='<<<'
+                    unset -v m[2] m[4]
+                    systemd-ask-password --timeout=0 "${m[*]}"
+                fi
+            else
+                plymouth --ping && plymouth --quit
+                read -s -r -p $'\n\n'"${m[*]}:" -n 1 reply
+            fi
         fi
-
-        dd if=/dev/null of=/overlay bs=1024 count=1 seek=$((overlay_size*1024)) 2> /dev/null
-        if [ -n "$setup" -a -n "$readonly_overlay" ]; then
-            RO_OVERLAY_LOOPDEV=$( losetup -f )
-            losetup $RO_OVERLAY_LOOPDEV /overlay
+        if [ -n "$overlayfs" ]; then
+            mkdir -m 0755 /run/overlayfs
+            mkdir -m 0755 /run/ovlwork
         else
-            losetup $OVERLAY_LOOPDEV /overlay
+            dd if=/dev/null of=/overlay bs=1024 count=1 seek=$((overlay_size*1024)) 2> /dev/null
+            if [ -n "$setup" -a -n "$readonly_overlay" ]; then
+                RO_OVERLAY_LOOPDEV=$(losetup -f --show /overlay)
+                over=$RO_OVERLAY_LOOPDEV
+            else
+                OVERLAY_LOOPDEV=$(losetup -f --show /overlay)
+                over=$OVERLAY_LOOPDEV
+            fi
         fi
     fi
 
     # set up the snapshot
-    sz=$(blockdev --getsz $BASE_LOOPDEV)
-    if [ -n "$readonly_overlay" ]; then
-        echo 0 $sz snapshot $BASE_LOOPDEV $OVERLAY_LOOPDEV N 8 | dmsetup create --readonly live-ro
-        base="/dev/mapper/live-ro"
-        over=$RO_OVERLAY_LOOPDEV
-    else
-        base=$BASE_LOOPDEV
-        over=$OVERLAY_LOOPDEV
+    if [ -z "$overlayfs" ]; then
+        if [ -n "$readonly_overlay" ] && [ -n "$OVERLAY_LOOPDEV" ]; then
+            echo 0 $sz snapshot $BASE_LOOPDEV $OVERLAY_LOOPDEV P 8 | dmsetup create --readonly live-ro
+            base="/dev/mapper/live-ro"
+        else
+            base=$BASE_LOOPDEV
+        fi
     fi
 
     if [ -n "$thin_snapshot" ]; then
         modprobe dm_thin_pool
-        mkdir /run/initramfs/thin-overlay
+        mkdir -m 0755 /run/initramfs/thin-overlay
 
         # In block units (512b)
         thin_data_sz=$(( $overlay_size * 1024 * 1024 / 512 ))
@@ -170,7 +236,7 @@ do_live_overlay() {
 
         # Create a snapshot of the base image
         echo 0 $sz thin /dev/mapper/live-overlay-pool 0 $base | dmsetup create live-rw
-    else
+    elif [ -z "$overlayfs" ]; then
         echo 0 $sz snapshot $base $over PO 8 | dmsetup create live-rw
     fi
 
@@ -178,17 +244,9 @@ do_live_overlay() {
     echo 0 $sz linear $BASE_LOOPDEV 0 | dmsetup create --readonly live-base
 }
 
-# live cd helper function
-do_live_from_base_loop() {
-    do_live_overlay
-}
-
 # we might have a genMinInstDelta delta file for anaconda to take advantage of
 if [ -e /run/initramfs/live/${live_dir}/osmin.img ]; then
     OSMINSQFS=/run/initramfs/live/${live_dir}/osmin.img
-fi
-
-if [ -n "$OSMINSQFS" ]; then
     # decompress the delta data
     dd if=$OSMINSQFS of=/run/initramfs/osmin.img 2> /dev/null
     OSMIN_SQUASHED_LOOPDEV=$( losetup -f )
@@ -204,13 +262,12 @@ fi
 if [ -e /run/initramfs/live/${live_dir}/${squash_image} ]; then
     SQUASHED="/run/initramfs/live/${live_dir}/${squash_image}"
 fi
-
-if [ -e "$SQUASHED" ] ; then
+if [ -e "$SQUASHED" ]; then
     if [ -n "$live_ram" ]; then
-        echo "Copying live image to RAM..."
-        echo "(this may take a few minutes)"
+        echo 'Copying live image to RAM...' > /dev/kmsg
+        echo ' (this may take a minute)' > /dev/kmsg
         dd if=$SQUASHED of=/run/initramfs/squashed.img bs=512 2> /dev/null
-        echo "Done copying live image to RAM."
+        echo 'Done copying live image to RAM.' > /dev/kmsg
         SQUASHED="/run/initramfs/squashed.img"
     fi
 
@@ -219,34 +276,32 @@ if [ -e "$SQUASHED" ] ; then
     mkdir -m 0755 -p /run/initramfs/squashfs
     mount -n -t squashfs -o ro $SQUASHED_LOOPDEV /run/initramfs/squashfs
 
-    if [ -f /run/initramfs/squashfs/LiveOS/ext3fs.img ]; then
-        FSIMG="/run/initramfs/squashfs/LiveOS/ext3fs.img"
-    elif [ -f /run/initramfs/squashfs/LiveOS/rootfs.img ]; then
+    if [ -f /run/initramfs/squashfs/LiveOS/rootfs.img ]; then
         FSIMG="/run/initramfs/squashfs/LiveOS/rootfs.img"
+    elif [ -f /run/initramfs/squashfs/LiveOS/ext3fs.img ]; then
+        FSIMG="/run/initramfs/squashfs/LiveOS/ext3fs.img"
     fi
 else
     # we might have an embedded fs image to use as rootfs (uncompressed live)
-    if [ -e /run/initramfs/live/${live_dir}/ext3fs.img ]; then
-        FSIMG="/run/initramfs/live/${live_dir}/ext3fs.img"
-    elif [ -e /run/initramfs/live/${live_dir}/rootfs.img ]; then
+    if [ -e /run/initramfs/live/${live_dir}/rootfs.img ]; then
         FSIMG="/run/initramfs/live/${live_dir}/rootfs.img"
+    elif [ -e /run/initramfs/live/${live_dir}/ext3fs.img ]; then
+        FSIMG="/run/initramfs/live/${live_dir}/ext3fs.img"
     fi
     if [ -n "$live_ram" ]; then
-        echo 'Copying live image to RAM...'
-        echo '(this may take a few minutes)'
+        echo 'Copying live image to RAM...' > /dev/kmsg
+        echo ' (this may take a minute or so)' > /dev/kmsg
         dd if=$FSIMG of=/run/initramfs/rootfs.img bs=512 2> /dev/null
-        echo 'Done copying live image to RAM.'
+        echo 'Done copying live image to RAM.' > /dev/kmsg
         FSIMG='/run/initramfs/rootfs.img'
     fi
 fi
 
 if [ -n "$FSIMG" ] ; then
-    BASE_LOOPDEV=$( losetup -f )
-
     if [ -n "$writable_fsimg" ] ; then
         # mount the provided filesystem read/write
-        echo "Unpacking live filesystem (may take some time)"
-        mkdir /run/initramfs/fsimg/
+        echo "Unpacking live filesystem (may take some time)" > /dev/kmsg
+        mkdir -m 0755 /run/initramfs/fsimg/
         if [ -n "$SQUASHED" ]; then
             cp -v $FSIMG /run/initramfs/fsimg/rootfs.img
         else
@@ -254,35 +309,70 @@ if [ -n "$FSIMG" ] ; then
         fi
         FSIMG=/run/initramfs/fsimg/rootfs.img
     fi
-    if [ -n "$writable_fsimg" ] || [ -z "$SQUASHED" -a -n "$live_ram" ] ||
+    opt=-r
+       # For writable DM images...
+    if [ -z "$SQUASHED" -a -n "$live_ram" -a -z "$overlayfs" ] ||
+       [ -n "$writable_fsimg" ] ||
        [ "$overlay" = none -o "$overlay" = None -o "$overlay" = NONE ]; then
-        losetup $BASE_LOOPDEV $FSIMG
-        sz=$(blockdev --getsz $BASE_LOOPDEV)
+        if [ -z "$readonly_overlay" ]; then
+            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
     else
-        # mount the filesystem read-only and add a dm snapshot for writes
-        losetup -r $BASE_LOOPDEV $FSIMG
-        do_live_from_base_loop
+        # Add a DM snapshot or OverlayFS for writes.
+        do_live_overlay
     fi
 fi
 
-[ -e "$SQUASHED" ] && umount -l /run/initramfs/squashfs
+[ -e "$SQUASHED" ] && [ -z "$overlayfs" ] && umount -l /run/initramfs/squashfs
 
 if [ -b "$OSMIN_LOOPDEV" ]; then
     # set up the devicemapper snapshot device, which will merge
     # the normal live fs image, and the delta, into a minimzied fs image
-    echo "0 $( blockdev --getsz $BASE_LOOPDEV ) snapshot $BASE_LOOPDEV $OSMIN_LOOPDEV N 8" | dmsetup create --readonly live-osimg-min
+    echo "0 $sz snapshot $BASE_LOOPDEV $OSMIN_LOOPDEV P 8" | dmsetup create --readonly live-osimg-min
 fi
 
-ROOTFLAGS="$(getarg rootflags)"
-if [ -n "$ROOTFLAGS" ]; then
-    ROOTFLAGS="-o $ROOTFLAGS"
+if [ -n "$reloadsysrootmountunit" ]; then
+    > /xor_overlayfs
+    systemctl daemon-reload
 fi
 
-ln -s /dev/mapper/live-rw /dev/root
+ROOTFLAGS="$(getarg rootflags)"
 
-if [ -z "$DRACUT_SYSTEMD" ]; then
-    printf 'mount %s /dev/mapper/live-rw %s\n' "$ROOTFLAGS" "$NEWROOT" > $hookdir/mount/01-$$-live.sh
+if [ -n "$overlayfs" ]; then
+    mkdir -m 0755 /run/rootfsbase
+    if [ -n "$reset_overlay" ] && [ -L /run/overlayfs ]; then
+        ovlfs=$(readlink /run/overlayfs)
+        info "Resetting the OverlayFS overlay directory."
+        rm -r -- ${ovlfs}/* ${ovlfs}/.* >/dev/null 2>&1
+    fi
+    if [ -n "$readonly_overlay" ]; then
+        mkdir -m 0755 /run/rootfsbase-r
+        mount -r $FSIMG /run/rootfsbase-r
+        mount -t overlay LiveOS_rootfs-r -oro,lowerdir=/run/overlayfs-r:/run/rootfsbase-r /run/rootfsbase
+    else
+        mount -r $FSIMG /run/rootfsbase
+    fi
+    if [ -z "$DRACUT_SYSTEMD" ]; then
+        #FIXME What to link to /dev/root? Is it even needed?
+        printf 'mount -t overlay LiveOS_rootfs -o%s,%s %s\n' "$ROOTFLAGS" \
+        'lowerdir=/run/rootfsbase,upperdir=/run/overlayfs,workdir=/run/ovlwork' \
+        "$NEWROOT" > $hookdir/mount/01-$$-live.sh
+    fi
+else
+    ln -s /dev/mapper/live-rw /dev/root
+    if [ -z "$DRACUT_SYSTEMD" ]; then
+        [ -n "$ROOTFLAGS" ] && ROOTFLAGS="-o $ROOTFLAGS"
+        printf 'mount %s /dev/mapper/live-rw %s\n' "$ROOTFLAGS" "$NEWROOT" > $hookdir/mount/01-$$-live.sh
+    fi
+    ln -s $BASE_LOOPDEV /run/rootfsbase
 fi
 
 need_shutdown

modules.d/90dmsquash-live/module-setup.sh

@@ -17,7 +17,7 @@ depends() {
 
 # called by dracut
 installkernel() {
-    instmods squashfs loop iso9660
+    instmods squashfs loop iso9660 overlay
 }
 
 # called by dracut

modules.d/90dmsquash-live/parse-dmsquash-live.sh

@@ -57,6 +57,6 @@ info "root was $liveroot, is now $root"
 # make sure that init doesn't complain
 [ -z "$root" ] && root="live"
 
-wait_for_dev -n /dev/mapper/live-rw
+wait_for_dev -n /run/rootfsbase
 
 return 0