Re: [PATCH 2/4] execute do_wic_image under a lock to ensure mountpoints remain mounted

[Henning Schild <henning.schild@siemens.com>]

LGTM

Henning

Am Wed, 22 Sep 2021 11:27:52 +0200
schrieb Felix Moessbauer <felix.moessbauer@siemens.com>:

> This patch adds the isar.lock to the do_wic_image task to ensure that
> the mountpoints are not unmounted by a simultaneously running wic
> task. Further, it makes mounting more robust by executing the
> wic task in a try / finally handler so that the mount points are
> unmounted even if the task itself fails.
> 
> Signed-off-by: Felix Moessbauer <felix.moessbauer@siemens.com>
> ---
>  meta/classes/wic-img.bbclass | 36
> ++++++++++++++++++++++-------------- 1 file changed, 22
> insertions(+), 14 deletions(-)
> 
> diff --git a/meta/classes/wic-img.bbclass
> b/meta/classes/wic-img.bbclass index d849ad9..e495c12 100644
> --- a/meta/classes/wic-img.bbclass
> +++ b/meta/classes/wic-img.bbclass
> @@ -138,23 +138,40 @@ python check_for_wic_warnings() {
>  
>  do_wic_image[file-checksums] += "${WKS_FILE_CHECKSUM}"
>  python do_wic_image() {
> -    bb.build.exec_func("generate_wic_image", d)
> -    bb.build.exec_func("check_for_wic_warnings", d)
> +    lock = bb.utils.lockfile(d.getVar("REPO_ISAR_DIR") +
> "/isar.lock", shared=True)
> +    bb.build.exec_func("wic_do_mounts", d)
> +    try:
> +        bb.build.exec_func("generate_wic_image", d)
> +        bb.build.exec_func("check_for_wic_warnings", d)
> +    finally:
> +        bb.build.exec_func("wic_undo_mounts", d)
> +        bb.utils.unlockfile(lock)
>  }
>  addtask wic_image before do_image after do_image_tools
>  
> -generate_wic_image() {
> +wic_do_mounts() {
>      buildchroot_do_mounts
>      sudo -s <<'EOSUDO'
> -        ( flock 9
>          for dir in ${BBLAYERS} ${STAGING_DIR} ${SCRIPTSDIR}
> ${BITBAKEDIR}; do mkdir -p ${BUILDCHROOT_DIR}/$dir
>              if ! mountpoint ${BUILDCHROOT_DIR}/$dir >/dev/null 2>&1;
> then mount --bind --make-private $dir ${BUILDCHROOT_DIR}/$dir
>              fi
>          done
> -        ) 9>${MOUNT_LOCKFILE}
>  EOSUDO
> +}
> +
> +wic_undo_mounts() {
> +    sudo -s <<'EOSUDO'
> +        for dir in ${BBLAYERS} ${STAGING_DIR} ${SCRIPTSDIR}
> ${BITBAKEDIR}; do
> +            if mountpoint -q ${BUILDCHROOT_DIR}/$dir; then
> +                umount ${BUILDCHROOT_DIR}/$dir
> +            fi
> +        done
> +EOSUDO
> +}
> +
> +generate_wic_image() {
>      export FAKEROOTCMD=${FAKEROOTCMD}
>      export BUILDDIR=${BUILDDIR}
>      export MTOOLS_SKIP_CHECK=1
> @@ -200,13 +217,4 @@ EOSUDO
>      done
>      rm -rf ${BUILDCHROOT_DIR}/${WICTMP}
>      rm -rf ${IMAGE_ROOTFS}/../pseudo
> -    sudo -s <<'EOSUDO'
> -        ( flock 9
> -        for dir in ${BBLAYERS} ${STAGING_DIR} ${SCRIPTSDIR}
> ${BITBAKEDIR}; do
> -            if mountpoint -q ${BUILDCHROOT_DIR}/$dir; then
> -                umount ${BUILDCHROOT_DIR}/$dir
> -            fi
> -        done
> -        ) 9>${MOUNT_LOCKFILE}
> -EOSUDO
>  }