Re: [PATCH v2 5/9] Move buildchroot mounts into dpkg-base class

[Alexander Smirnov <asmirnov@ilbers.de>]

On 02/13/2018 11:05 PM, Jan Kiszka wrote:
> From: Jan Kiszka <jan.kiszka@siemens.com>
> 
> This avoids the unfortunate setup_mounts task which is either not
> executed on rebuilds or causes excessive package rebuilds. We just need
> ensure prior to switching into the buildchroot that all mount points are
> populated.
> 
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
> ---
>   meta/classes/dpkg-base.bbclass                   | 13 +++++++++-
>   meta/recipes-devtools/buildchroot/buildchroot.bb | 30 +++---------------------
>   2 files changed, 15 insertions(+), 28 deletions(-)
> 
> diff --git a/meta/classes/dpkg-base.bbclass b/meta/classes/dpkg-base.bbclass
> index a45fbce..66132da 100644
> --- a/meta/classes/dpkg-base.bbclass
> +++ b/meta/classes/dpkg-base.bbclass
> @@ -2,7 +2,7 @@
>   # Copyright (C) 2017 Siemens AG
>   
>   # Add dependency from buildchroot creation
> -do_build[depends] = "buildchroot:do_setup_mounts"
> +do_build[depends] = "buildchroot:do_build"
>   
>   # Add dependency between Isar recipes
>   DEPENDS ?= ""
> @@ -20,11 +20,22 @@ dpkg_runbuild() {
>       die "This should never be called, overwrite it in your derived class"
>   }
>   
> +mount_if_needed() {
> +
> +    # The test may race with parallel builds. So probe, mount if needed, and
> +    # then only fail if both the mount and yet another probe failed as well.
> +    grep -q $2 /proc/mounts || sudo mount $1 $2 || grep -q $2 /proc/mounts

This could lead to have lots of remounts on the same folder during 
parallel execution. This should be done in a separate task and protected 
by [lockfiles].

Alex

> +}
> +
>   # Wrap the function dpkg_runbuild with the bind mount for buildroot
>   do_build() {
>       mkdir -p ${BUILDROOT}
>       sudo mount --bind ${WORKDIR} ${BUILDROOT}
>   
> +    mount_if_needed "--bind ${DEPLOY_DIR_APT}/${DISTRO}" ${BUILDCHROOT_DIR}/isar-apt
> +    mount_if_needed "-t devtmpfs -o mode=0755,nosuid devtmpfs" ${BUILDCHROOT_DIR}/dev
> +    mount_if_needed "-t proc none" ${BUILDCHROOT_DIR}/proc
> +
>       dpkg_runbuild
>   
>       sudo umount ${BUILDROOT} 2>/dev/null || true
> diff --git a/meta/recipes-devtools/buildchroot/buildchroot.bb b/meta/recipes-devtools/buildchroot/buildchroot.bb
> index 570c0ad..cd91228 100644
> --- a/meta/recipes-devtools/buildchroot/buildchroot.bb
> +++ b/meta/recipes-devtools/buildchroot/buildchroot.bb
> @@ -60,7 +60,9 @@ do_build() {
>           -e 's|##DIR_HOOKS##|./'"$WORKDIR_REL"'/hooks_multistrap|g' \
>              "${WORKDIR}/multistrap.conf.in" > "${WORKDIR}/multistrap.conf"
>   
> -    do_setup_mounts
> +    sudo mount --bind ${DEPLOY_DIR_APT}/${DISTRO} ${BUILDCHROOT_DIR}/isar-apt
> +    sudo mount -t devtmpfs -o mode=0755,nosuid devtmpfs ${BUILDCHROOT_DIR}/dev
> +    sudo mount -t proc none ${BUILDCHROOT_DIR}/proc
>   
>       # Create root filesystem
>       sudo -E multistrap -a ${DISTRO_ARCH} -d "${BUILDCHROOT_DIR}" -f "${WORKDIR}/multistrap.conf"
> @@ -70,30 +72,4 @@ do_build() {
>   
>       # Configure root filesystem
>       sudo chroot ${BUILDCHROOT_DIR} /configscript.sh
> -
> -    do_cleanup_mounts
> -}
> -
> -# Invalidate stamp for do_setup_mounts before each build start.
> -# This will guarantee that this function will be executed once
> -# per build.
> -python __anonymous() {
> -    stamp = d.getVar("STAMP") + ".do_setup_mounts." + d.getVarFlag("do_setup_mounts", 'stamp-extra-info')
> -    os.remove(stamp) if os.path.exists(stamp) else None
> -}
> -
> -do_setup_mounts[stamp-extra-info] = "${DISTRO}-${DISTRO_ARCH}"
> -
> -do_setup_mounts() {
> -    sudo mount --bind ${DEPLOY_DIR_APT}/${DISTRO} ${BUILDCHROOT_DIR}/isar-apt
> -    sudo mount -t devtmpfs -o mode=0755,nosuid devtmpfs ${BUILDCHROOT_DIR}/dev
> -    sudo mount -t proc none ${BUILDCHROOT_DIR}/proc
> -}
> -
> -addtask setup_mounts after do_build
> -
> -do_cleanup_mounts() {
> -    sudo umount ${BUILDCHROOT_DIR}/isar-apt 2>/dev/null || true
> -    sudo umount ${BUILDCHROOT_DIR}/dev 2>/dev/null || true
> -    sudo umount ${BUILDCHROOT_DIR}/proc 2>/dev/null || true
>   }
> 

-- 
With best regards,
Alexander Smirnov

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