Merge lp:~smoser/ubuntu/precise/lxc/btrfs-clone-support into lp:ubuntu/precise/lxc

[Scott Moser]

This adds minimally tested btrfs clone support.

[lp:~smoser/ubuntu/precise/lxc/btrfs-clone-support]

52. By Scott Moser on 2012-01-26

0029-btrfs-clone-support.patch: add support for cloning via
btrfs snapshots (LP: #921921).

53. By Scott Moser on 2012-01-26

fix issue in clone, where rootfs was not written

54. By Scott Moser on 2012-01-26

lxc-create: if no '-B' flag is given and btrfs is available, use it

=== modified file '.pc/applied-patches'
--- .pc/applied-patches	2012-01-25 14:22:51 +0000
+++ .pc/applied-patches	2012-01-26 16:18:34 +0000
@@ -39,3 +39,4 @@
 0026-support-new-reboot.patch
 0027-fix-lxc-netstat.patch
 0028-recursively-rmdir-cgroups.patch
+0029-btrfs-clone-support.patch

=== modified file 'debian/changelog'
--- debian/changelog	2012-01-25 14:22:51 +0000
+++ debian/changelog	2012-01-26 16:18:34 +0000
@@ -1,3 +1,10 @@
+lxc (0.7.5-3ubuntu13) precise; urgency=low
+
+  * 0029-btrfs-clone-support.patch: add support for cloning via
+    btrfs snapshots (LP: #921921).
+
+ -- Scott Moser <[e-mail]>  Thu, 26 Jan 2012 09:14:49 -0500
+
 lxc (0.7.5-3ubuntu12) precise; urgency=low
 
   * If the kernel supports container reboot disambuation, then don't drop

=== added file 'debian/patches/0029-btrfs-clone-support.patch'
--- debian/patches/0029-btrfs-clone-support.patch	1970-01-01 00:00:00 +0000
+++ debian/patches/0029-btrfs-clone-support.patch	2012-01-26 16:18:34 +0000
@@ -0,0 +1,132 @@
+Description: add btrfs cloning support
+ This patch adds support for btrfs filesystem clone support via the 'btrfs'
+ command.  if a container has been created with '-B btrfs', then lxc-clone
+ will automatically use it. Ie, there is no need to specify '-s' or other
+ arguments to lxc-clone.
+ .
+ This patch should probably be forwarded after some testing.
+Author: Scott Moser <[e-mail]>
+Forwarded: no
+Bug: https://bugs.launchpad.net/bugs/921921
+--- a/src/lxc/lxc-clone.in
++++ b/src/lxc/lxc-clone.in
+@@ -40,8 +40,8 @@ help() {
+ 
+ shortoptions='ho:n:sL:v:'
+ longoptions='help,orig:,name:,snapshot,fssize,vgname'
+-lxc_path=@LXCPATH@
+-bindir=@BINDIR@
++lxc_path=/var/lib/lxc
++bindir=/usr/bin
+ snapshot=no
+ lxc_size=2G
+ lxc_vg=lxc
+@@ -197,6 +197,13 @@ if [ -b $oldroot ]; then
+ 	mkdir -p $lxc_path/$lxc_new/rootfs
+ 	mount /dev/$lxc_vg/$lxc_new $rootfs || { echo "failed to mount new rootfs"; cleanup; }
+ 	mounted=1
++elif out=$(btrfs subvolume list "$lxc_path/$lxc_orig/rootfs" 2>&1); then
++	out=$(btrfs subvolume snapshot "$lxc_path/$lxc_orig/rootfs" "$rootfs" 2>&1)
++	if [ $? -ne 0 ]; then
++		echo "failed btrfs subvolume snapshot of $lxc_path/$lxc_orig/rootfs"
++		cleanup
++	fi
++	echo "lxc.rootfs = $rootfs" >> "$lxc_path/$lxc_new/config"
+ else
+ 	cp -a $lxc_path/$lxc_orig/rootfs $lxc_path/$lxc_new/rootfs || cleanup
+ 	echo "lxc.rootfs = $rootfs" >> $lxc_path/$lxc_new/config
+--- a/src/lxc/lxc-create.in
++++ b/src/lxc/lxc-create.in
+@@ -25,6 +25,8 @@ usage() {
+     echo "usage: lxc-create -n <name> [-f configuration] [-t template] [-h] [fsopts] -- [template_options]"
+     echo "   fsopts: -B none"
+     echo "   fsopts: -B lvm [--lvname lvname] [--vgname vgname] [--fstype fstype] [--fssize fssize]"
++    echo "   fsopts: -B btrfs"
++    echo "           flag is not necessary, if possible btrfs support will be used"
+ #    echo "   fsopts: -B union [--uniontype overlayfs]"
+ #    echo "   fsopts: -B loop [--fstype fstype] [--fssize fssize]"
+ #    echo "   fsopts: -B qemu-nbd [--type qed|qcow2|raw] [--fstype fstype] [--fssize fssize] # Qemu qed disk format"
+@@ -67,7 +69,7 @@ longoptions='help,name:,config:,template
+ lxc_path=@LXCPATH@
+ bindir=@BINDIR@
+ templatedir=@LXCTEMPLATEDIR@
+-backingstore=none
++backingstore=_unset
+ fstype=ext4
+ fssize=500M
+ vgname=lxc
+@@ -162,11 +164,13 @@ if [ "$(id -u)" != "0" ]; then
+    exit 1
+ fi
+ 
+-if [ $backingstore != "none" -a $backingstore != "lvm" ]; then
+-    echo "only 'none' and 'lvm' backing stores are known"
+-    usage
+-    exit 1
+-fi
++case "$backingstore" in
++    lvm|none|btrfs|_unset) :;;
++    *) echo "'$backingstore' is not known ('none', 'lvm', 'btrfs')"
++       usage
++       exit 1
++       ;;
++esac
+ 
+ if [ -d "$lxc_path/$lxc_name" ]; then
+     echo "'$lxc_name' already exists"
+@@ -174,6 +178,21 @@ if [ -d "$lxc_path/$lxc_name" ]; then
+ fi
+ 
+ rootfs="$lxc_path/$lxc_name/rootfs"
++
++if [ "$backingstore" = "_unset" -o "$backingstore" = "btrfs" ]; then
++    # if no backing store was given, then see if btrfs would work
++    if which btrfs >/dev/null 2>&1 &&
++        btrfs filesystem df "$lxc_path/" >/dev/null 2>&1; then
++        backingstore="btrfs"
++    else
++        if [ "$backingstore" = "btrfs" ]; then
++            echo "missing 'btrfs' command or $lxc_path is not btrfs";
++            exit 1;
++        fi
++        backingstore="none"
++    fi
++fi
++
+ if [ $backingstore = "lvm" ]; then
+     which vgscan > /dev/null
+     if [ $? -ne 0 ]; then
+@@ -201,6 +220,12 @@ if [ $backingstore = "lvm" ]; then
+         echo "please delete it (using \"lvremove $rootdev\") and try again"
+         exit 1
+     fi
++elif [ "$backingstore" = "btrfs" ]; then
++    mkdir "$lxc_path/$lxc_name"
++    if ! out=$(btrfs subvolume create "$rootfs" 2>&1); then
++        echo "failed to create subvolume in $rootfs: $out";
++        exit 1;
++    fi
+ fi
+ 
+ cleanup() {
+@@ -231,7 +256,7 @@ fi
+ cp $lxc_config $lxc_path/$lxc_name/config
+ 
+ # Create the fs as needed
+-mkdir $rootfs
++[ -d "$rootfs" ] || mkdir "$rootfs"
+ if [ $backingstore = "lvm" ]; then
+     lvcreate -L $fssize -n $lvname $vgname || exit 1
+     udevadm settle
+--- a/src/lxc/lxc-destroy.in
++++ b/src/lxc/lxc-destroy.in
+@@ -105,5 +105,9 @@ if [ ! -z "$rootdev" ]; then
+ 		fi
+ 	fi
+ fi
++if out=$(btrfs subvolume list "$lxc_path/$lxc_name/rootfs" 2>&1); then
++	out=$(btrfs subvolume delete "$lxc_path/$lxc_name/rootfs" 2>&1) ||
++		echo "WARN: failed btrfs subvolume delete: $out"
++fi
+ # recursively remove the container to remove old container configuration
+ rm -rf --preserve-root $lxc_path/$lxc_name

=== modified file 'debian/patches/series'
--- debian/patches/series	2012-01-25 14:22:51 +0000
+++ debian/patches/series	2012-01-26 16:18:34 +0000
@@ -39,3 +39,4 @@
 0026-support-new-reboot.patch
 0027-fix-lxc-netstat.patch
 0028-recursively-rmdir-cgroups.patch
+0029-btrfs-clone-support.patch

=== modified file 'src/lxc/lxc-clone.in'
--- src/lxc/lxc-clone.in	2012-01-20 14:34:54 +0000
+++ src/lxc/lxc-clone.in	2012-01-26 16:18:34 +0000
@@ -40,8 +40,8 @@
 
 shortoptions='ho:n:sL:v:'
 longoptions='help,orig:,name:,snapshot,fssize,vgname'
-lxc_path=@LXCPATH@
-bindir=@BINDIR@
+lxc_path=/var/lib/lxc
+bindir=/usr/bin
 snapshot=no
 lxc_size=2G
 lxc_vg=lxc
@@ -197,6 +197,13 @@
 	mkdir -p $lxc_path/$lxc_new/rootfs
 	mount /dev/$lxc_vg/$lxc_new $rootfs || { echo "failed to mount new rootfs"; cleanup; }
 	mounted=1
+elif out=$(btrfs subvolume list "$lxc_path/$lxc_orig/rootfs" 2>&1); then
+	out=$(btrfs subvolume snapshot "$lxc_path/$lxc_orig/rootfs" "$rootfs" 2>&1)
+	if [ $? -ne 0 ]; then
+		echo "failed btrfs subvolume snapshot of $lxc_path/$lxc_orig/rootfs"
+		cleanup
+	fi
+	echo "lxc.rootfs = $rootfs" >> "$lxc_path/$lxc_new/config"
 else
 	cp -a $lxc_path/$lxc_orig/rootfs $lxc_path/$lxc_new/rootfs || cleanup
 	echo "lxc.rootfs = $rootfs" >> $lxc_path/$lxc_new/config

=== modified file 'src/lxc/lxc-create.in'
--- src/lxc/lxc-create.in	2012-01-23 17:24:53 +0000
+++ src/lxc/lxc-create.in	2012-01-26 16:18:34 +0000
@@ -25,6 +25,8 @@
     echo "usage: lxc-create -n <name> [-f configuration] [-t template] [-h] [fsopts] -- [template_options]"
     echo "   fsopts: -B none"
     echo "   fsopts: -B lvm [--lvname lvname] [--vgname vgname] [--fstype fstype] [--fssize fssize]"
+    echo "   fsopts: -B btrfs"
+    echo "           flag is not necessary, if possible btrfs support will be used"
 #    echo "   fsopts: -B union [--uniontype overlayfs]"
 #    echo "   fsopts: -B loop [--fstype fstype] [--fssize fssize]"
 #    echo "   fsopts: -B qemu-nbd [--type qed|qcow2|raw] [--fstype fstype] [--fssize fssize] # Qemu qed disk format"
@@ -67,7 +69,7 @@
 lxc_path=@LXCPATH@
 bindir=@BINDIR@
 templatedir=@LXCTEMPLATEDIR@
-backingstore=none
+backingstore=_unset
 fstype=ext4
 fssize=500M
 vgname=lxc
@@ -162,11 +164,13 @@
    exit 1
 fi
 
-if [ $backingstore != "none" -a $backingstore != "lvm" ]; then
-    echo "only 'none' and 'lvm' backing stores are known"
-    usage
-    exit 1
-fi
+case "$backingstore" in
+    lvm|none|btrfs|_unset) :;;
+    *) echo "'$backingstore' is not known ('none', 'lvm', 'btrfs')"
+       usage
+       exit 1
+       ;;
+esac
 
 if [ -d "$lxc_path/$lxc_name" ]; then
     echo "'$lxc_name' already exists"
@@ -174,6 +178,21 @@
 fi
 
 rootfs="$lxc_path/$lxc_name/rootfs"
+
+if [ "$backingstore" = "_unset" -o "$backingstore" = "btrfs" ]; then
+    # if no backing store was given, then see if btrfs would work
+    if which btrfs >/dev/null 2>&1 &&
+        btrfs filesystem df "$lxc_path/" >/dev/null 2>&1; then
+        backingstore="btrfs"
+    else
+        if [ "$backingstore" = "btrfs" ]; then
+            echo "missing 'btrfs' command or $lxc_path is not btrfs";
+            exit 1;
+        fi
+        backingstore="none"
+    fi
+fi
+
 if [ $backingstore = "lvm" ]; then
     which vgscan > /dev/null
     if [ $? -ne 0 ]; then
@@ -201,6 +220,12 @@
         echo "please delete it (using \"lvremove $rootdev\") and try again"
         exit 1
     fi
+elif [ "$backingstore" = "btrfs" ]; then
+    mkdir "$lxc_path/$lxc_name"
+    if ! out=$(btrfs subvolume create "$rootfs" 2>&1); then
+        echo "failed to create subvolume in $rootfs: $out";
+        exit 1;
+    fi
 fi
 
 cleanup() {
@@ -231,7 +256,7 @@
 cp $lxc_config $lxc_path/$lxc_name/config
 
 # Create the fs as needed
-mkdir $rootfs
+[ -d "$rootfs" ] || mkdir "$rootfs"
 if [ $backingstore = "lvm" ]; then
     lvcreate -L $fssize -n $lvname $vgname || exit 1
     udevadm settle

=== modified file 'src/lxc/lxc-destroy.in'
--- src/lxc/lxc-destroy.in	2012-01-20 10:56:32 +0000
+++ src/lxc/lxc-destroy.in	2012-01-26 16:18:34 +0000
@@ -105,5 +105,9 @@
 		fi
 	fi
 fi
+if out=$(btrfs subvolume list "$lxc_path/$lxc_name/rootfs" 2>&1); then
+	out=$(btrfs subvolume delete "$lxc_path/$lxc_name/rootfs" 2>&1) ||
+		echo "WARN: failed btrfs subvolume delete: $out"
+fi
 # recursively remove the container to remove old container configuration
 rm -rf --preserve-root $lxc_path/$lxc_name