Re: [PATCH] rootfs: Use separate mounts lock file

[Jan Kiszka <jan.kiszka@siemens.com>]

On 08.07.21 17:22, Anton Mikanovich wrote:
> MOUNTS_LOCKFILE value inside rootfs.bbclass is overwritten by later
> inherited buildchroot.bbclass. We need to use other value name.
> 
> Signed-off-by: Anton Mikanovich <amikan@ilbers.de>
> ---
>  meta/classes/rootfs.bbclass | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/meta/classes/rootfs.bbclass b/meta/classes/rootfs.bbclass
> index 50d6408..6ce2cf9 100644
> --- a/meta/classes/rootfs.bbclass
> +++ b/meta/classes/rootfs.bbclass
> @@ -26,7 +26,7 @@ export LANG = "C"
>  export LANGUAGE = "C"
>  export LC_ALL = "C"
>  
> -MOUNT_LOCKFILE = "${ROOTFSDIR}.lock"
> +IMAGE_MOUNT_LOCKFILE = "${ROOTFSDIR}.lock"
>  
>  rootfs_do_mounts[weight] = "3"
>  rootfs_do_mounts() {
> @@ -70,7 +70,7 @@ rootfs_do_mounts() {
>                  mount --bind '${REPO_BASE_DIR}' '${ROOTFSDIR}/base-apt'
>          fi
>  
> -        ) 9>'${MOUNT_LOCKFILE}'
> +        ) 9>'${IMAGE_MOUNT_LOCKFILE}'
>  EOSUDO
>  }
>  
> @@ -103,7 +103,7 @@ rootfs_undo_mounts() {
>              umount -R ${ROOTFSDIR}/proc
>          mountpoint -q '${ROOTFSDIR}/dev' && \
>              umount -R ${ROOTFSDIR}/dev
> -        ) 9>'${MOUNT_LOCKFILE}'
> +        ) 9>'${IMAGE_MOUNT_LOCKFILE}'
>  EOSUDO
>  }
>  
> 

Definitely a good catch, but I'm still wrapping my head around it. We
either have really separated rootfs'es here so that separated lock files
are fine, or we rather want rootfs_do_mounts to be locked against
buildchroot_do_mounts as well. At least conceptually, even if they well
never run in parallel in practice. In that case, MOUNT_LOCKFILE in
rootfs.bbclass should be made a weak assignment, to clarify that
buildchroot.bbclass will win, irrespective of any ordering.

Jan

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