openstack
/
diskimage-builder
Code Issues Proposed changes

lib: common-functions: Fix tmpfs umounting 

It has been observed that some chroot operations spawn additional
processes which rely on chroot files. More specifically, zypper, uses
gpg-agent to import and validate gpg keys for its repositories. This
gpg-agent process may stay alive for longer which prevents unmounting of
the tmpfs directory since the gpg-agent process still uses libraries etc
which were present in the chroot. We try to solve this by using walking
all the pids in /proc to find out the running processes in the chroot and
kill them gracefully. If that fails for whatever reason, then we simply
keep trying to umount the tmpfs directory before we give up.

The gpg-agent process usually terminates soon after its home directory
disappears but on fast systems we can reach the 'umount tmpfs' point
before gpg-agent terminates by itself. The solution is generic enough so
other 'chroot processes' can also be handled appropriately.

Change-Id: Iccf332678c79266113e76f062884fc5ee79e515d
This commit is contained in:
Markos Chandras 2016-10-31 21:43:47 +00:00
parent be1e563524
commit a1f57b8cad
1 changed files with 29 additions and 2 deletions
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31
lib/common-functions
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@ -134,21 +134,48 @@ function eval_run_d () {
trap - ERR
}
function kill_chroot_processes () {
if [ -z "${1}" ]; then
echo "ERROR: no chroot directory specified"
exit 1
fi
for piddir in /proc/[0-9]*; do
pid=${piddir##/proc/}
pidname=$(cat $piddir/comm 2>/dev/null || echo "unknown")
# If there are open files from the chroot, just kill the process using
# these files.
if sudo readlink -f $piddir/root | grep -q $TMP_BUILD_DIR; then
echo "Killing chroot process: '${pidname}($pid)'"
sudo kill $pid
fi
done
}
function cleanup_build_dir () {
if ! timeout 5 sh -c " while ! sudo rm -rf $TMP_BUILD_DIR/built; do sleep 1; done"; then
echo "ERROR: unable to cleanly remove $TMP_BUILD_DIR/built"
exit 1
fi
sudo rm -rf $TMP_BUILD_DIR/mnt
kill_chroot_processes $TMP_BUILD_DIR
if tmpfs_check 0; then
sudo umount -f $TMP_BUILD_DIR || true
# If kill_chroot_processes did not succeed then we have to wait for
# init to reap the orphaned chroot processes
if ! timeout 120 sh -c "while ! sudo umount -f $TMP_BUILD_DIR; do sleep 1; done"; then
echo "ERROR: failed to umount the $TMP_BUILD_DIR tmpfs mount point"
exit 1
fi
fi
rm -rf --one-file-system $TMP_BUILD_DIR
}
function cleanup_image_dir () {
kill_chroot_processes $TMP_IMAGE_DIR
if tmpfs_check 0; then
sudo umount -f $TMP_IMAGE_DIR || true
if ! timeout 120 sh -c "while ! sudo umount -f $TMP_IMAGE_DIR; do sleep 1; done"; then
echo "ERROR: failed to umount the $TMP_IMAGE_DIR tmpfs mount point"
exit 1
fi
fi
rm -rf --one-file-system $TMP_IMAGE_DIR
}