Add orange flavor btrfs support

examples/orange/Dockerfile

@@ -51,7 +51,10 @@ RUN apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install -y --no-ins
   locales \
   kbd \
   podman \
-  xz-utils
+  btrfs-progs \
+  btrfsmaintenance \
+  xz-utils && \
+  apt-get clean && rm -rf /var/lib/apt/lists/*
 
 # Hack to prevent systemd-firstboot failures while setting keymap, this is known
 # Debian issue (T_T) https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=790955
@@ -75,6 +78,9 @@ RUN cp /usr/share/systemd/tmp.mount /etc/systemd/system
 # the default cloud-init
 RUN locale-gen --lang en_US.UTF-8
 
+# Add default snapshotter setup
+ADD snapshotter.yaml /etc/elemental/config.d/snapshotter.yaml
+
 # Generate initrd with required elemental services
 RUN elemental --debug init -f
 

examples/orange/snapshotter.yaml

@@ -0,0 +1,5 @@
+snapshotter:
+  type: btrfs
+  max-snaps: 4
+  config:
+    snapper: false

pkg/action/init.go

@@ -18,6 +18,7 @@ package action
 
 import (
 	"fmt"
+	"path/filepath"
 	"strings"
 
 	"github.com/rancher/elemental-toolkit/v2/pkg/constants"
@@ -69,7 +70,12 @@ func RunInit(cfg *types.RunConfig, spec *types.InitSpec) error {
 	if kernel != constants.KernelPath {
 		cfg.Config.Logger.Debugf("Creating kernel symlink from %s to %s", kernel, constants.KernelPath)
 		_ = cfg.Fs.Remove(constants.KernelPath)
-		err = cfg.Fs.Symlink(kernel, constants.KernelPath)
+		relKernel, err := filepath.Rel(filepath.Dir(constants.KernelPath), kernel)
+		if err != nil {
+			cfg.Config.Logger.Errorf("could set a relative path from '%s' to '%s': %v", constants.KernelPath, kernel, err)
+			return err
+		}
+		err = cfg.Fs.Symlink(relKernel, constants.KernelPath)
 		if err != nil {
 			cfg.Config.Logger.Errorf("failed creating kernel symlink")
 			return err
@@ -89,7 +95,7 @@ func RunInit(cfg *types.RunConfig, spec *types.InitSpec) error {
 		cfg.Config.Logger.Errorf("dracut failed with output: %s", output)
 	}
 
-	cfg.Config.Logger.Debugf("darcut output: %s", output)
+	cfg.Config.Logger.Debugf("dracut output: %s", output)
 
 	initrd, err := utils.FindInitrd(cfg.Fs, "/")
 	if err != nil || !strings.HasPrefix(initrd, constants.ElementalInitrd) {
@@ -99,9 +105,15 @@ func RunInit(cfg *types.RunConfig, spec *types.InitSpec) error {
 
 	cfg.Config.Logger.Debugf("Creating initrd symlink from %s to %s", initrd, constants.InitrdPath)
 	_ = cfg.Fs.Remove(constants.InitrdPath)
-	err = cfg.Fs.Symlink(initrd, constants.InitrdPath)
+	relInitrd, err := filepath.Rel(filepath.Dir(constants.InitrdPath), initrd)
+	if err != nil {
+		cfg.Config.Logger.Errorf("could set a relative path from '%s' to '%s': %v", constants.InitrdPath, initrd, err)
+		return err
+	}
+	err = cfg.Fs.Symlink(relInitrd, constants.InitrdPath)
 	if err != nil {
 		cfg.Config.Logger.Errorf("failed creating initrd symlink")
+		return err
 	}
 
 	return err

pkg/constants/constants.go

@@ -89,6 +89,7 @@ const (
 	GrubDefEntry           = "Elemental"
 	GrubFallback           = "default_fallback"
 	GrubPassiveSnapshots   = "passive_snaps"
+	GrubActiveSnapshot     = "active_snap"
 	ElementalBootloaderBin = "/usr/lib/elemental/bootloader"
 
 	// Mountpoints or links to images and partitions

pkg/features/embedded/grub-config/etc/elemental/grub.cfg

@@ -65,30 +65,45 @@ function set_loopdevice {
 
 ## Sources bootargs from the current volume
 function source_bootargs {
-  source (${volume})/etc/cos/bootargs.cfg
-  source (${volume})/etc/elemental/bootargs.cfg
+  source (${volume})/${root_subpath}etc/cos/bootargs.cfg
+  source (${volume})/${root_subpath}etc/elemental/bootargs.cfg
 }
 
 ## Defines the volume and image to boot from for active or passive boots
 function set_volume {
   if [ "${snapshotter}" == "btrfs" ]; then
+    # apply btrfs default subvolume if applicable
     set btrfs_relative_path="y"
     set volume="${root}"
-    if [ -n "${1}" ]; then
-      set img="@/.snapshots/${1}/snapshot"
-      btrfs-mount-subvol ($root) / ${img}
+    # check if active snap is defined with default top level volume
+    if [ -d "@/.snapshots/${active_snap}/snapshot" ]; then
+      if [ -n "${1}" ]; then
+        set img="@/.snapshots/${1}/snapshot"
+      else
+        set img="@/.snapshots/${active_snap}/snapshot"
+      fi
+      set root_subpath="${img}/"
+    else
+      # if not in top level use subvolume based mounts 
+      set root_subpath=""
+      if [ -n "${1}" ]; then
+        set img="@/.snapshots/${1}/snapshot"
+        btrfs-mount-subvol ($root) / ${img}
+      fi
     fi
   elif [ -z "${1}" ]; then
+    set root_subpath=""
     set_loopdevice /.snapshots/active
   else
+    set root_subpath=""
     set img="/.snapshots/${1}/snapshot.img"
     set_loopdevice ${img}
   fi
 }
 
 menuentry "${display_name}" --id active {
   set mode=active
-  search --no-floppy --label --set=root ${state_label}
+  search --no-floppy --set root --label ${state_label}
   set_volume
   source_bootargs
   linux (${volume})${kernel} ${kernelcmd} ${extra_cmdline} ${extra_active_cmdline}
@@ -98,7 +113,7 @@ menuentry "${display_name}" --id active {
 for passive_snap in ${passive_snaps}; do
   menuentry "${display_name} (snapshot ${passive_snap})" --id passive${passive_snap} ${passive_snap} {
     set mode=passive
-    search --no-floppy --label --set=root ${state_label}
+    search --no-floppy --set root --label ${state_label}
     set_volume ${2}
     source_bootargs
     linux (${volume})${kernel} ${kernelcmd} ${extra_cmdline} ${extra_passive_cmdline}
@@ -108,7 +123,7 @@ done
 
 menuentry "${display_name} recovery" --id recovery {
   set mode=recovery
-  search --no-floppy --label --set=root ${recovery_label}
+  search --no-floppy --set root --label ${recovery_label}
 
   # Check the presence of the image and fallback to legacy path if not present
   set img=/boot/recovery.img

pkg/features/embedded/grub-default-bootargs/etc/elemental/bootargs.cfg

@@ -23,5 +23,5 @@ else
   set kernelcmd="console=tty1 console=ttyS0 root=LABEL=${state_label} ${img_arg} ${snap_arg} elemental.mode=${mode} elemental.oemlabel=${oem_label} panic=5 security=selinux fsck.mode=force fsck.repair=yes"
 fi
 
-set kernel=/boot/vmlinuz
-set initramfs=/boot/initrd
+set kernel=/${root_subpath}boot/vmlinuz
+set initramfs=/${root_subpath}boot/initrd

pkg/snapshotter/btrfs-backend.go

@@ -119,27 +119,14 @@ func newBtrfsBackend(cfg *types.Config, maxSnapshots int) *btrfsBackend {
 
 // Probe tests the given device and returns the found state as a backendStat struct
 func (b *btrfsBackend) Probe(device string, mountpoint string) (backendStat, error) {
-	var rootVolume, snapshotsVolume bool
 	var stat backendStat
 
-	volumes, err := b.getSubvolumes(mountpoint)
+	rootVolume, snapshotsVolume, err := b.getStateSubvolumes(mountpoint)
 	if err != nil {
 		return stat, err
 	}
 
-	b.cfg.Logger.Debugf(
-		"Looking for subvolume ids %d and %d in subvolume list: %v",
-		rootSubvolID, snapshotsSubvolID, volumes,
-	)
-	for _, vol := range volumes {
-		if vol.id == rootSubvolID {
-			rootVolume = true
-		} else if vol.id == snapshotsSubvolID {
-			snapshotsVolume = true
-		}
-	}
-
-	if rootVolume && snapshotsVolume {
+	if (rootVolume != nil) && (snapshotsVolume != nil) {
 		id, err := b.getActiveSnapshot(mountpoint)
 		if err != nil {
 			return stat, err
@@ -411,14 +398,36 @@ func (b btrfsBackend) findSubvolumeByPath(rootDir, path string) (int, error) {
 
 // getSubvolumes lists all btrfs subvolumes for the given root
 func (b btrfsBackend) getSubvolumes(rootDir string) (btrfsSubvolList, error) {
-	out, err := b.cfg.Runner.Run("btrfs", "subvolume", "list", "--sort=path", rootDir)
+	out, err := b.cfg.Runner.Run("btrfs", "subvolume", "list", "-a", "--sort=path", rootDir)
 	if err != nil {
 		b.cfg.Logger.Errorf("failed listing btrfs subvolumes: %s", err.Error())
 		return nil, err
 	}
 	return parseVolumes(strings.TrimSpace(string(out))), nil
 }
 
+func (b btrfsBackend) getStateSubvolumes(rootDir string) (rootVolume *btrfsSubvol, snapshotsVolume *btrfsSubvol, err error) {
+	volumes, err := b.getSubvolumes(rootDir)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	snapshots := filepath.Join(rootSubvol, snapshotsPath)
+	b.cfg.Logger.Debugf(
+		"Looking for subvolumes %s and %s in subvolume list: %v",
+		rootSubvol, snapshots, volumes,
+	)
+	for _, vol := range volumes {
+		if vol.path == rootSubvol {
+			rootVolume = &vol
+		} else if vol.path == snapshots {
+			snapshotsVolume = &vol
+		}
+	}
+
+	return rootVolume, snapshotsVolume, err
+}
+
 // getActiveSnapshot returns the active snapshot. Zero value means there is no active or default snapshot
 func (b btrfsBackend) getActiveSnapshot(rootDir string) (int, error) {
 	out, err := b.cfg.Runner.Run("btrfs", "subvolume", "get-default", rootDir)
@@ -448,7 +457,7 @@ func parseVolumes(rawBtrfsList string) btrfsSubvolList {
 		match := re.FindStringSubmatch(strings.TrimSpace(scanner.Text()))
 		if match != nil {
 			id, _ := strconv.Atoi(match[1])
-			path := match[2]
+			path := strings.TrimPrefix(match[2], "<FS_TREE>/")
 			list = append(list, btrfsSubvol{id: id, path: path})
 		}
 	}
@@ -530,11 +539,19 @@ func (b btrfsBackend) findStateMount(device string) (rootDir string, stateMount
 		if len(lineFields) != 2 {
 			continue
 		}
-		if strings.Contains(lineFields[1], constants.RunningStateDir) {
-			stateMount = lineFields[1]
-		} else if match := r.FindStringSubmatch(lineFields[0]); match != nil {
-			rootDir = lineFields[1]
-			snapshotID, _ = strconv.Atoi(match[1])
+
+		subStart := strings.Index(lineFields[0], "[/")
+		subEnd := strings.LastIndex(lineFields[0], "]")
+
+		if subStart != -1 && subEnd != -1 {
+			subVolume := lineFields[0][subStart+2 : subEnd]
+
+			if subVolume == rootSubvol {
+				stateMount = lineFields[1]
+			} else if match := r.FindStringSubmatch(subVolume); match != nil {
+				rootDir = lineFields[1]
+				snapshotID, _ = strconv.Atoi(match[1])
+			}
 		}
 	}
 

pkg/snapshotter/btrfs.go

@@ -31,8 +31,6 @@ import (
 
 const (
 	rootSubvol        = "@"
-	rootSubvolID      = 257
-	snapshotsSubvolID = 258
 	snapshotsPath     = ".snapshots"
 	snapshotPathTmpl  = ".snapshots/%d/snapshot"
 	snapshotPathRegex = `.snapshots/(\d+)/snapshot`
@@ -265,8 +263,9 @@ func (b *Btrfs) CloseTransaction(snapshot *types.Snapshot) (err error) {
 		return err
 	}
 
-	_ = b.setBootloader()
+	// cleanup snapshots before setting bootloader otherwise deleted snapshots may show up in bootloader
 	_ = b.backend.SnapshotsCleanup(b.rootDir)
+	_ = b.setBootloader(snapshot.ID)
 	return nil
 }
 
@@ -379,7 +378,7 @@ func (b *Btrfs) getPassiveSnapshots() ([]int, error) {
 }
 
 // setBootloader sets the bootloader variables to update new passives
-func (b *Btrfs) setBootloader() error {
+func (b *Btrfs) setBootloader(activeSnapshotID int) error {
 	var passives, fallbacks []string
 
 	b.cfg.Logger.Infof("Setting bootloader with current passive snapshots")
@@ -404,6 +403,7 @@ func (b *Btrfs) setBootloader() error {
 	envs := map[string]string{
 		constants.GrubFallback:         fallbackList,
 		constants.GrubPassiveSnapshots: snapsList,
+		constants.GrubActiveSnapshot:   strconv.Itoa(activeSnapshotID),
 		"snapshotter":                  constants.BtrfsSnapshotterType,
 	}
 

pkg/snapshotter/snapper-backend.go

@@ -30,8 +30,9 @@ import (
 )
 
 const (
-	snapperRootConfig = "/etc/snapper/configs/root"
-	snapperSysconfig  = "/etc/sysconfig/snapper"
+	snapperRootConfig    = "/etc/snapper/configs/root"
+	snapperSysconfig     = "/etc/sysconfig/snapper"
+	snapperDefaultconfig = "/etc/default/snapper"
 )
 
 var _ subvolumeBackend = (*snapperBackend)(nil)
@@ -220,7 +221,11 @@ func (s snapperBackend) configureSnapper(snapshotPath string) error {
 	}
 
 	sysconfigData := map[string]string{}
-	sysconfig := filepath.Join(snapshotPath, snapperSysconfig)
+	sysconfig := filepath.Join(snapshotPath, snapperDefaultconfig)
+	if ok, _ := utils.Exists(s.cfg.Fs, sysconfig); !ok {
+		sysconfig = filepath.Join(snapshotPath, snapperSysconfig)
+	}
+
 	if ok, _ := utils.Exists(s.cfg.Fs, sysconfig); ok {
 		sysconfigData, err = utils.LoadEnvFile(s.cfg.Fs, sysconfig)
 		if err != nil {