Re: [libvirt] [PATCH 3/4] Trim /proc & /sys subtrees before mounting new instances

From: "Daniel P. Berrange&quot;&lt;berrange(a)redhat.com&gt; Both /proc and /sys may have sub-mounts in them from the host OS. We must explicitly unmount them all before mounting the new instance over that location. If we don't then /proc/mounts will show the sub-mounts as existing, even though nothing will be able to access them, due to the over-mount. Signed-off-by: Daniel P. Berrange&lt;berrange(a)redhat.com&gt; --- src/lxc/lxc_container.c | 61 ++++++++++++++++++++++++++++++++++++----------- 1 file changed, 47 insertions(+), 14 deletions(-) @@ -1054,13 +1057,36 @@ static int lxcContainerUnmountOldFS(void) qsort(mounts, nmounts, sizeof(mounts[0]), lxcContainerChildMountSort); + *mountsret = mounts; + *nmountsret = nmounts; + ret = 0; + +cleanup: + endmntent(procmnt); + return ret; +} + +static int lxcContainerUnmountSubtree(const char *prefix, + bool isOldRootFS) +{ + char **mounts = NULL; + size_t nmounts = 0; + size_t i; + int saveErrno; + const char *failedUmount = NULL; + int ret = -1; + + VIR_DEBUG("Unmount subtreee from %s", prefix); + + if (lxcContainerGetSubtree(prefix,&mounts,&nmounts)< 0) + return -1; for (i = 0 ; i< nmounts ; i++) { VIR_DEBUG("Umount %s", mounts[i]); if (umount(mounts[i])< 0) { char ebuf[1024]; failedUmount = mounts[i]; saveErrno = errno; - VIR_WARN("Failed to unmount '%s', trying to detach root '%s': %s", + VIR_WARN("Failed to unmount '%s', trying to detach subtree '%s': %s", failedUmount, mounts[nmounts-1], virStrerror(errno, ebuf, sizeof(ebuf))); break;