[PATCH v3 09/10] sstate: add caching to rootfs

[Adriaan Schmidt <adriaan.schmidt@siemens.com>]

We cache the output of do_rootfs. Again "sudo tar" to preserve
ownerships and permissions. In addition, it can happen that there are
active mounts while tar'ing the rootfs (there shouldn't be, but I've
seen cases where deb-src is mounted). Unfortunately --one-file-system
does not stop at bind mounts, so we use a trick with a temporary mount
to ensure that we don't package more than we want.

Signed-off-by: Adriaan Schmidt <adriaan.schmidt@siemens.com>
---
 meta/classes/rootfs.bbclass | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/meta/classes/rootfs.bbclass b/meta/classes/rootfs.bbclass
index b38de66..e0604e0 100644
--- a/meta/classes/rootfs.bbclass
+++ b/meta/classes/rootfs.bbclass
@@ -265,3 +265,30 @@ python do_rootfs() {
     pass
 }
 addtask rootfs before do_build
+
+do_rootfs[depends] = "base-apt:do_cache isar-apt:do_cache_config"
+
+SSTATETASKS += "do_rootfs"
+ROOTFS_SSTATE = "${WORKDIR}/rootfs-sstate"
+do_rootfs[dirs] += "${ROOTFS_SSTATE} ${WORKDIR}/mnt/rootfs"
+do_rootfs[cleandirs] += "${ROOTFS_SSTATE}"
+do_rootfs[sstate-plaindirs] = "${ROOTFS_SSTATE}"
+do_rootfs[sstate-interceptfuncs] = "rootfs_sstate_prepare"
+
+# the buildchroot is owned by root, so we need some sudoing to pack and unpack
+rootfs_sstate_prepare() {
+    sudo mount --bind ${WORKDIR}/rootfs ${WORKDIR}/mnt/rootfs -o ro
+    sudo tar -C ${WORKDIR}/mnt -cpf ${ROOTFS_SSTATE}/rootfs.tar --one-file-system rootfs
+    sudo umount ${WORKDIR}/mnt/rootfs
+}
+do_rootfs_sstate_prepare[lockfiles] = "${REPO_ISAR_DIR}/isar.lock"
+
+rootfs_sstate_finalize() {
+    sudo tar -C ${WORKDIR} -xpf ${ROOTFS_SSTATE}/rootfs.tar
+}
+
+python do_rootfs_setscene() {
+    sstate_setscene(d)
+    bb.build.exec_func('rootfs_sstate_finalize', d)
+}
+addtask do_rootfs_setscene
-- 
2.30.2