handle clone of btrfs snapshots

Fix determination of $oldroot from the config file. The old code had the ' in the wrong place and didn't account for whitespace between the = and the rootfs. Set $rootfs based on $oldroot instead of forcing it to be in $lxc_path/$lxc_new/rootfs. This allows for btrfs snapshot to be made even if $lxc_path isn't on the same filesystem. If $oldroot isn't a subvolume, fall back to making a copy. Signed-off-by: Dwight Engen <dwight.engen@oracle.com>

handle clone of btrfs snapshots
d4eb4ab1 · Dwight Engen · Stéphane Graber · 5ae26abb · d4eb4ab1
Commit d4eb4ab1 authored Sep 26, 2012 by Dwight Engen Committed by Stéphane Graber Oct 25, 2012
Hide whitespace changes
Inline Side-by-side

Showing with 9 additions and 10 deletions

lxc-clone.in src/lxc/lxc-clone.in +9 -10

No files found.
--- a/src/lxc/lxc-clone.in
+++ b/src/lxc/lxc-clone.in
@@ -183,13 +183,13 @@ if [ -e  $lxc_path/$lxc_orig/fstab ];then
 fi

 echo "Copying rootfs..."
-rootfs=$lxc_path/$lxc_new/rootfs
+oldroot=`grep lxc.rootfs $lxc_path/$lxc_orig/config | awk -F'[= \t]+' '{ print $2 }'`
+rootfs=`echo $oldroot |sed "s/$lxc_orig/$lxc_new/"`

 container_running=True
 lxc-info -s -n $lxc_orig|grep RUNNING >/dev/null 2>&1 || container_running=False

 sed -i '/lxc.rootfs/d' $lxc_path/$lxc_new/config
-oldroot=`grep lxc.rootfs $lxc_path/$lxc_orig/config | awk -F= '{ print $2 '}`
 if [ -b $oldroot ]; then
    type vgscan || { echo "$(basename $0): lvm is not installed" >&2; false; }
    lvdisplay $oldroot > /dev/null 2>&1 || { echo "$(basename $0): non-lvm blockdev cloning is not supported" >&2; false; }
@@ -221,7 +221,7 @@ if [ -b $oldroot ]; then
        lvcreate -L $lxc_size $lxc_vg -n ${lxc_lv_prefix}$lxc_new
        echo "lxc.rootfs = /dev/$lxc_vg/${lxc_lv_prefix}$lxc_new" >> $lxc_path/$lxc_new/config
        # and mount it so we can tweak it
-        mkdir -p $lxc_path/$lxc_new/rootfs
+        mkdir -p $rootfs
        mkfs -t $fstype /dev/$lxc_vg/${lxc_lv_prefix}$lxc_new
        mount /dev/$lxc_vg/${lxc_lv_prefix}$lxc_new $rootfs || { echo "$(basename $0): failed to mount new rootfs" >&2; false; }
        mounted=1
@@ -233,16 +233,15 @@ if [ -b $oldroot ]; then
        lvrename $lxc_vg/${lxc_lv_prefix}${lxc_new}_snapshot $lxc_vg/${lxc_lv_prefix}$lxc_new
        echo "lxc.rootfs = /dev/$lxc_vg/${lxc_lv_prefix}$lxc_new" >> $lxc_path/$lxc_new/config
        # and mount it so we can tweak it
-        mkdir -p $lxc_path/$lxc_new/rootfs
+        mkdir -p $rootfs
        mount /dev/$lxc_vg/${lxc_lv_prefix}$lxc_new $rootfs || { echo "$(basename $0): failed to mount new rootfs" >&2; false; }
        mounted=1
    fi

-elif out=$(btrfs subvolume list "$lxc_path/$lxc_orig/rootfs" 2>&1); then
-
-    out=$(btrfs subvolume snapshot "$lxc_path/$lxc_orig/rootfs" "$rootfs" 2>&1) || { echo "$(basename $0): btrfs snapshot failed" >&2; false; }
+elif which btrfs >/dev/null 2>&1 && btrfs subvolume list $oldroot >/dev/null 2>&1; then
+    # if oldroot is a btrfs subvolume, assume they want a snapshot
+    btrfs subvolume snapshot "$oldroot" "$rootfs" 2>&1 || { echo "$(basename $0): btrfs snapshot failed" >&2; false; }
    echo "lxc.rootfs = $rootfs" >> "$lxc_path/$lxc_new/config"
-
 else
    if [ $snapshot = "yes" ]; then
        echo "$(basename $0): cannot snapshot a directory" >&2
@@ -252,8 +251,8 @@ else
        lxc-freeze -n $lxc_orig
        frozen=1
    fi
-    mkdir -p $lxc_path/$lxc_new/rootfs/
-    rsync -ax $lxc_path/$lxc_orig/rootfs/ $lxc_path/$lxc_new/rootfs/
+    mkdir -p $rootfs/
+    rsync -ax $oldroot/ $rootfs/
    echo "lxc.rootfs = $rootfs" >> $lxc_path/$lxc_new/config
    if [ $container_running = "True" ]; then
        lxc-unfreeze -n $lxc_orig