Btrfs migration 4: build stamping

Dockerfile

@@ -22,6 +22,7 @@ RUN apt-get install -y \
     flex \
     parted \
     fdisk \
+    btrfs-progs \
     python3-dev \
     python3-libfdt \
     python3-setuptools \

README.md

@@ -119,7 +119,7 @@ sudo apt install git build-essential crossbuild-essential-arm64 bc bison flex \
 For assembling disk images — debos, bmaptool, and zeekstd all need to be installed from source:
 
 ```bash
-sudo apt install golang pipx pigz cargo parted fdisk mmdebstrap \
+sudo apt install golang pipx pigz cargo parted fdisk btrfs-progs mmdebstrap \
     systemd-resolved systemd-container qemu-user-binfmt \
     libglib2.0-dev libostree-dev fakemachine
 

build-images.sh

@@ -23,20 +23,10 @@ trap cleanup EXIT
 
 bmaptool copy "$IMG_OUT"/debian-rootfs.img.zst "$IMG_OUT"/debian-rootfs.img
 sync "$IMG_OUT"/debian-rootfs.img
-TMP=`mktemp`
-chmod 644 "$TMP"
 
 # Boot entries are pure BLS in /boot/loader/entries, read directly by U-Boot's
 # 'bls' bootmeth (no extlinux.conf). Nothing to rewrite here for the boot menu.
 
-debugfs -R "cat /usr/lib/os-release"  "$IMG_OUT"/debian-rootfs.img > "$TMP"
-echo "BUILD_ID=$BUILD_ID" >> "$TMP"
-debugfs -w -R "rm /usr/lib/os-release" "$IMG_OUT"/debian-rootfs.img
-debugfs -w -R "write $TMP /usr/lib/os-release" "$IMG_OUT"/debian-rootfs.img
-sync "$IMG_OUT"/debian-rootfs.img
-
-rm -f "$TMP"
-
 for s in 512 4096; do
 	echo "Creating images for $s-byte sector size"
 	truncate -s "$IMGSIZE" "$TMPDIR"/debian-"$s"-nobootloader-"$BUILD_ID".img

build-rootfs-img.sh

@@ -5,6 +5,17 @@
 
 set -e
 
+# Capture Git information
+[ -n "${GIT_HASH}" ] || GIT_HASH=$(git rev-parse --short HEAD 2>/dev/null || echo "unknown")
+[ -n "${GIT_BRANCH}" ] || GIT_BRANCH=$(git symbolic-ref --short HEAD 2>/dev/null || git describe --tags --exact-match 2>/dev/null || echo "detached")
+[ -n "${GIT_MSG}" ] || GIT_MSG=$(git log -1 --pretty=format:"%s" 2>/dev/null | sed 's/[\"()]/\\&/g; s/'"'"'/\\&/g' || echo "unknown")
+[ -n "${GIT_INFO}" ] || GIT_INFO="${GIT_BRANCH}@${GIT_HASH}: ${GIT_MSG}"
+GIT_INFO=$(echo "$GIT_INFO" | tr -dc '[:alnum:][:space:]')
+
+# Build identifier: CI sets BUILD_ID in the environment (e.g. "build-1419"); otherwise
+# fall back to a UTC timestamp, same default/format as build-images.sh.
+: "${BUILD_ID:=$(date -u '+%Y%m%d-%H%M')}"
+
 if [ -c /dev/kvm -a -w /dev/kvm ]; then
 	# Have virtualization support, can use fakemachine (default, fast, safe)
 	DEBOS="debos -c $(nproc) -m 6Gb"
@@ -29,7 +40,7 @@ mkdir -p "$IMG_OUT"/linux_tmp
 cp -r "$LINUX_OUT"/* "$IMG_OUT"/linux_tmp
 
 echo "Creating the root FS image"
-$DEBOS --artifactdir="$IMG_OUT" -t imagesize:"$IMGSIZE" -t kerneldir:linux_tmp debian-rk3576-img.yaml
+$DEBOS --artifactdir="$IMG_OUT" -t imagesize:"$IMGSIZE" -t kerneldir:linux_tmp -t gitinfo:"$GIT_INFO" -t buildid:"$BUILD_ID" debian-rk3576-img.yaml
 sync "$IMG_OUT"/debian-nobootloader.img
 
 owner=$(stat -c %u "$IMG_OUT"/debian-nobootloader.img)

debian-rk3576-img.yaml

@@ -1,16 +1,25 @@
 {{ $sectorsize := or .sectorsize 512 }}
-{{ $imagesize := or .imagesize "4GiB" }}
-{{ $kerneldir := or .kerneldir "prebuilt/linux" }}
-{{ $cmdline := or .cmdline "audit=0 console=tty1 console=ttyS0,1500000n8" }}
+{{ $imagesize  := or .imagesize  "4GiB" }}
+{{ $kerneldir  := or .kerneldir  "prebuilt/linux" }}
+{{ $cmdline    := or .cmdline    "audit=0 console=tty1 console=ttyS0,1500000n8" }}
+{{ $fslabel    := or .fslabel    "flipperos" }}
+{{ $gitinfo    := or .gitinfo    "unknown" }}
+{{ $buildid    := or .buildid    "unknown" }}
+{{- /* fs-wide btrfs mount options. ssd is FORCED (loopback/eMMC isn't reliably
+       detected as non-rotational). */ -}}
+{{ $btrfsopts  := or .btrfsopts  "compress=zstd,noatime,ssd,discard=async" }}
+{{ $rootdev    := "findmnt -fn --nofsroot -o SOURCE --target $IMAGEMNTDIR" }}
 
 architecture: arm64
 sectorsize: {{ $sectorsize }}
-
 actions:
   - action: unpack
     description: Load a tarball of the root filesystem
     file: debian-ospack.tar.gz
 
+  # debos formats btrfs (default flags, random FSUUID), mounts the top level at
+  # $IMAGEMNTDIR, and records the standard root fstab line + root=UUID.
+  # fsck:false -> passno 0 (no boot-time fsck for btrfs).
   - action: image-partition
     imagename: debian-nobootloader.img
     imagesize: {{ $imagesize }}
@@ -21,17 +30,85 @@ actions:
         start: 32KiB
         end: 64MiB
       - name: root
-        fs: ext4
+        fs: btrfs
+        fslabel: {{ $fslabel }}
+        fsck: false
         start: 64MiB
         end: -1MiB
-        flags: [ boot ]
     mountpoints:
       - mountpoint: /
         partition: root
-        options: [ x-systemd.growfs ]
+        options: [ compress=zstd, noatime, ssd, discard=async, x-systemd.growfs ]
+
+  # Subvolume layout (no reformat). /boot is a TOP-LEVEL subvolume named "boot"
+  # (not "@boot") so it sits outside the per-profile root subvolumes -> a single shared
+  # /boot that root snapshots never capture, and so U-Boot, which reads the default
+  # (top-level) subvolume, resolves /boot/extlinux/... straight into it. Keep the default
+  # subvolume as the top level (do NOT set a default subvolume) or U-Boot won't see /boot.
+  - action: run
+    description: Create subvolumes and mount the layout
+    chroot: false
+    command: |
+      set -eu
+      ROOTPART="$({{ $rootdev }})"
+
+      # debos has the top level (subvolid=5) mounted here; create subvolumes on it.
+      # @Minimal is the common base / build target; @snapshots holds runtime snapshots.
+      for sv in @Minimal boot @home @snapshots @var-log @var-cache; do
+        btrfs subvolume create "$IMAGEMNTDIR/$sv"
+      done
+      umount "$IMAGEMNTDIR"
+
+      # Mount @Minimal at the mount point debos owns, then nest the rest under it.
+      mount -t btrfs -o "{{ $btrfsopts }},subvol=@Minimal" "$ROOTPART" "$IMAGEMNTDIR"
+      mkdir -p "$IMAGEMNTDIR/boot" \
+               "$IMAGEMNTDIR/home" \
+               "$IMAGEMNTDIR/var/log" \
+               "$IMAGEMNTDIR/var/cache"
+      mount -t btrfs -o "{{ $btrfsopts }},subvol=boot"       "$ROOTPART" "$IMAGEMNTDIR/boot"
+      # Keep /boot uncompressed so U-Boot can read the kernel/dtb/initrd regardless
+      # of whether its btrfs driver was built with zstd support. The property is
+      # stored on the subvolume and inherited by files added later (kernel updates).
+      btrfs property set "$IMAGEMNTDIR/boot" compression none
+      mount -t btrfs -o "{{ $btrfsopts }},subvol=@home"      "$ROOTPART" "$IMAGEMNTDIR/home"
+      mount -t btrfs -o "{{ $btrfsopts }},subvol=@var-log"   "$ROOTPART" "$IMAGEMNTDIR/var/log"
+      mount -t btrfs -o "{{ $btrfsopts }},subvol=@var-cache" "$ROOTPART" "$IMAGEMNTDIR/var/cache"
 
+  # debos writes the standard root line into /etc/fstab and root=UUID into the cmdline;
+  # the root subvolume is selected by the appended rootflags. @Desktop is the default root
+  # (the desktop); the other profiles' BLS entries append rootflags=subvol=@<profile>
+  # and the last rootflags= on the line wins. (Deploy still happens into @Minimal.)
   - action: filesystem-deploy
-    append-kernel-cmdline: {{ $cmdline }}
+    append-kernel-cmdline: rootflags=subvol=@Desktop {{ $cmdline }}
+
+  # Add fstab entries for the non-root subvolumes (debos only generated the root
+  # line). The FSUUID is read back at build time. These (/boot, /home, /var/log,
+  # /var/cache) are shared by every profile root. @snapshots is intentionally omitted
+  # -- it holds runtime snapshots, managed on demand, never auto-mounted.
+  - action: run
+    description: Append subvolume entries to /etc/fstab
+    chroot: false
+    command: |
+      set -eu
+      ROOTPART="$({{ $rootdev }})"
+      FSUUID="$(blkid -o value -s UUID -p -c none "$ROOTPART")"
+      cat >> "$IMAGEMNTDIR/etc/fstab" <<EOF
+      UUID=$FSUUID  /boot        btrfs  {{ $btrfsopts }},subvol=boot        0  0
+      UUID=$FSUUID  /home        btrfs  {{ $btrfsopts }},subvol=@home       0  0
+      UUID=$FSUUID  /var/log     btrfs  {{ $btrfsopts }},subvol=@var-log    0  0
+      UUID=$FSUUID  /var/cache   btrfs  {{ $btrfsopts }},subvol=@var-cache  0  0
+      EOF
+
+  # journald's append-heavy writes fragment badly under btrfs copy-on-write. Pre-create
+  # the journal dir with NODATACOW (chattr +C) while it's still empty, so the journal
+  # files written on first boot inherit it. (+C also implies no compression.)
+  - action: run
+    description: Disable CoW on the systemd journal directory
+    chroot: false
+    command: |
+      set -eu
+      mkdir -p "$IMAGEMNTDIR/var/log/journal"
+      chattr +C "$IMAGEMNTDIR/var/log/journal"
 
   - action: overlay
     description: Copy Linux kernel packages into the target
@@ -43,3 +120,191 @@ actions:
     description: Install Linux kernel packages inside the target
     chroot: true
     command: find /var/cache/linux-kernel -name linux-image-\*.deb -a ! -name \*-dbg_\* -print0 | xargs -0 apt install -y
+
+  # Default session for every profile: the no-DE multi-user target, where the cog-seat1
+  # kiosk runs (and @TV's kodi, enabled under multi-user). Only @Desktop overrides this to
+  # graphical.target (for sddm); @Minimal/@Router/@TV all stay on multi-user.
+  - action: run
+    description: Set the default boot target to multi-user (only @Desktop overrides)
+    chroot: true
+    command: systemctl set-default multi-user.target
+
+  # The ospack tarball already carries a BUILD_GIT (the ospack build's git state), and the
+  # ospack is cached/reused across image builds. Replace it with THIS image build's git
+  # state so the stamp reflects the actual image. Stamped into @Minimal before it is snapshotted 
+  # to @Minimal_stock, so every profile inherits it via COW. Both are consumed by the MOTD/banner.
+  - action: run
+    description: Save GIT info
+    chroot: true
+    command: |
+      # /etc/os-release is normally a symlink to /usr/lib/os-release; resolve it so
+      # sed edits the real file in place instead of replacing the symlink.
+      osr="$(readlink -f /etc/os-release)"
+      sed -i '/^BUILD_GIT=/d; /^BUILD_ID=/d' "$osr"
+      echo 'BUILD_GIT="{{ $gitinfo }}"' >> "$osr"
+      echo 'BUILD_ID={{ $buildid }}' >> "$osr"
+
+  # ===========================================================================
+  # Stock (RO) bases + per-profile bootable roots.
+  #
+  # @Minimal_stock is the RO golden image of the common base. Each profile is a
+  # WRITABLE snapshot of it (COW: shares the base, only profile packages add new extents),
+  # mounted at $IMAGEMNTDIR so standard debos `apt`/`overlay` actions install into it;
+  # it is then locked RO and the writable @<profile> bootable root is snapshotted from it.
+  # BLS selects a profile via rootflags=subvol=@<profile>. The kernel lives in
+  # @Minimal_stock (installed above), so every profile inherits it via COW. /boot,
+  # @home and @var-* are separate top-level subvols shared by all profiles.
+  #
+  # KDE and TV-Media-Box install their packages (apt) + config (overlay); only @Desktop changes
+  # its default target (to graphical, for sddm) -- TV/Router/Minimal stay on multi-user.
+  # Router applies only its config overlay (NM AP/WAN + ip-forwarding); no packages needed.
+  # ===========================================================================
+
+  - action: run
+    description: Lock @Minimal_stock (RO), re-create @Minimal from it, free the mountpoint
+    chroot: false
+    command: |
+      set -eu
+      sync
+      ROOTPART="$({{ $rootdev }})"                 # @Minimal is still mounted at $IMAGEMNTDIR
+      # Mount the btrfs top level at a fixed path and KEEP it mounted for the whole profile
+      # sequence: it is our stable handle for `findmnt --target` (device lookup then works in
+      # every debos mode, whether or not $IMAGEMNTDIR is mounted) and where the subvols live.
+      TOP="${IMAGEMNTDIR%/}.toplevel"
+      mkdir -p "$TOP"
+      mount -t btrfs -o subvolid=5 "$ROOTPART" "$TOP"
+      btrfs subvolume snapshot -r "$TOP/@Minimal" "$TOP/@Minimal_stock"
+      # release @Minimal and its nested submounts so we can replace it and profile
+      # factories can mount here
+      findmnt -rno TARGET --submounts "$IMAGEMNTDIR" \
+        | awk '{ print length, $0 }' | sort -rn | cut -d" " -f2- \
+        | while read -r mp; do umount "$mp"; done
+      # Re-create @Minimal as a writable child of the golden base (parent = @Minimal_stock)
+      # so it matches the other profiles -- which are snapshots of their _stock -- instead
+      # of being the build origin with no parent.
+      btrfs subvolume delete "$TOP/@Minimal"
+      btrfs subvolume snapshot "$TOP/@Minimal_stock" "$TOP/@Minimal"
+
+  # --- @Desktop ------------------------------------------------------------------
+  - action: run
+    description: Snapshot writable @Desktop_stock and mount it
+    chroot: false
+    command: |
+      set -eu
+      TOP="${IMAGEMNTDIR%/}.toplevel"
+      ROOTPART="$(findmnt -fn --nofsroot -o SOURCE --target "$TOP")"
+      btrfs subvolume snapshot "$TOP/@Minimal_stock" "$TOP/@Desktop_stock"
+      mount -t btrfs -o "{{ $btrfsopts }},subvol=@Desktop_stock" "$ROOTPART" "$IMAGEMNTDIR"
+  - action: apt
+    description: KDE desktop packages
+    recommends: false        # image is minbase/no-recommends; deps are listed explicitly
+    packages:
+      - bluedevil
+      - blueman
+      - breeze-gtk-theme
+      - kde-config-gtk-style
+      - kde-config-screenlocker
+      - kde-spectacle
+      - kde-standard
+      - konsole
+      - kscreen
+      - mpv
+      - plasma-discover
+      - plasma-nm
+      - plasma-systemmonitor
+      - powerdevil
+      - sddm
+      - sddm-theme-breeze
+      - systemsettings
+  - action: overlay
+    description: KDE profile config (sddm autologin, plasma, wallpaper)
+    source: overlays/profile-kde
+    destination: /
+  - action: run
+    description: Make the KDE desktop the default session on @Desktop
+    chroot: true
+    command: systemctl set-default graphical.target
+  - action: run
+    description: Lock @Desktop_stock RO and spawn writable @Desktop
+    chroot: false
+    command: |
+      set -eu
+      TOP="${IMAGEMNTDIR%/}.toplevel"
+      umount "$IMAGEMNTDIR"
+      btrfs property set "$TOP/@Desktop_stock" ro true
+      btrfs subvolume snapshot "$TOP/@Desktop_stock" "$TOP/@Desktop"
+
+  # --- @TV-Media-Box ---------------------------------------------------------
+  - action: run
+    description: Snapshot writable @TV-Media-Box_stock and mount it
+    chroot: false
+    command: |
+      set -eu
+      TOP="${IMAGEMNTDIR%/}.toplevel"
+      ROOTPART="$(findmnt -fn --nofsroot -o SOURCE --target "$TOP")"
+      btrfs subvolume snapshot "$TOP/@Minimal_stock" "$TOP/@TV-Media-Box_stock"
+      mount -t btrfs -o "{{ $btrfsopts }},subvol=@TV-Media-Box_stock" "$ROOTPART" "$IMAGEMNTDIR"
+  - action: apt
+    description: TV media box packages
+    recommends: false
+    packages:
+      - cage
+      - kodi
+      - kodi-eventclients-kodi-send
+  - action: overlay
+    description: TV media box profile config (kodi, enabled under multi-user)
+    source: overlays/profile-tv-media-box
+    destination: /
+  - action: run
+    description: Lock @TV-Media-Box_stock RO and spawn writable @TV-Media-Box
+    chroot: false
+    command: |
+      set -eu
+      TOP="${IMAGEMNTDIR%/}.toplevel"
+      umount "$IMAGEMNTDIR"
+      btrfs property set "$TOP/@TV-Media-Box_stock" ro true
+      btrfs subvolume snapshot "$TOP/@TV-Media-Box_stock" "$TOP/@TV-Media-Box"
+
+  # --- @Router ---------------------------------------------------------------
+  - action: run
+    description: Snapshot writable @Router_stock and mount it
+    chroot: false
+    command: |
+      set -eu
+      TOP="${IMAGEMNTDIR%/}.toplevel"
+      ROOTPART="$(findmnt -fn --nofsroot -o SOURCE --target "$TOP")"
+      btrfs subvolume snapshot "$TOP/@Minimal_stock" "$TOP/@Router_stock"
+      mount -t btrfs -o "{{ $btrfsopts }},subvol=@Router_stock" "$ROOTPART" "$IMAGEMNTDIR"
+  # @Router needs no packages beyond Minimal (NetworkManager + dnsmasq-base + wpa_supplicant
+  # are common); it just adds the AP/WAN connections + ip-forwarding via the overlay. Its
+  # default session stays multi-user (inherited); NM autoconnect brings the router up.
+  - action: overlay
+    description: Router profile config (NM AP/WAN connections, ip-forwarding)
+    source: overlays/profile-router
+    destination: /
+  - action: run
+    description: Fix NetworkManager connection permissions on @Router
+    chroot: true
+    command: chmod 600 /etc/NetworkManager/system-connections/*.nmconnection
+  - action: run
+    description: Lock @Router_stock RO and spawn writable @Router
+    chroot: false
+    command: |
+      set -eu
+      TOP="${IMAGEMNTDIR%/}.toplevel"
+      umount "$IMAGEMNTDIR"
+      btrfs property set "$TOP/@Router_stock" ro true
+      btrfs subvolume snapshot "$TOP/@Router_stock" "$TOP/@Router"
+
+  # Unmount the top level and remount @Minimal at the mountpoint debos owns, so its
+  # image-partition Cleanup can unmount it and detach the loop. (The profile builds left
+  # $IMAGEMNTDIR unmounted, and the lingering top-level mount would hold the loop busy.)
+  - action: run
+    description: Unmount the top level and remount @Minimal for debos cleanup
+    chroot: false
+    command: |
+      set -eu
+      TOP="${IMAGEMNTDIR%/}.toplevel"
+      ROOTPART="$(findmnt -fn --nofsroot -o SOURCE --target "$TOP")"
+      umount "$TOP"; rmdir "$TOP"
+      mount -t btrfs -o "{{ $btrfsopts }},subvol=@Minimal" "$ROOTPART" "$IMAGEMNTDIR"