[Lxc-users] [PATCH 1/1] cgroups: fix broken support for deprecated ns cgroup
Arun M
arunmahadevaiyer at gmail.com
Mon Mar 5 20:38:21 UTC 2012
Applied the patch. Able to lxc-execute without any issues (2.6.32 kernel).
Thanks,
Arun
On Tue, Mar 6, 2012 at 12:43 AM, Serge Hallyn <serge.hallyn at canonical.com>wrote:
> when using ns cgroup, use /cgroup/<init-cgroup> rather than
> /cgroup/<init-cgroup>/lxc
>
> At least lxc-start, lxc-stop, lxc-cgroup, lxc-console and lxc-ls work
> with this patch. I've tested this in a 2.6.35 kernel with ns cgroup,
> and in a 3.2 kernel without ns cgroup.
>
> Note also that because of the check for container reboot support,
> if we're using the ns cgroup we now end up with a /cgroup/<container>/2
> cgroup created, empty, by the clone(CLONE_NEWPID). I'm really not
> sure how much time we want to spend cleaning such things up since
> ns cgroup is deprecated in kernel.
>
> Signed-off-by: Serge Hallyn <serge at hallyn.com>
> ---
> src/lxc/cgroup.c | 60
> +++++++++++++++++++++++++++++++---------------------
> src/lxc/lxc-ls.in | 6 ++++-
> 2 files changed, 41 insertions(+), 25 deletions(-)
>
> diff --git a/src/lxc/cgroup.c b/src/lxc/cgroup.c
> index cc3910a..9af199d 100644
> --- a/src/lxc/cgroup.c
> +++ b/src/lxc/cgroup.c
> @@ -137,6 +137,21 @@ found:
> return dsg;
> }
>
> +static int get_cgroup_flags(struct mntent *mntent)
> +{
> + int flags = 0;
> +
> +
> + if (hasmntopt(mntent, "ns"))
> + flags |= CGROUP_NS_CGROUP;
> +
> + if (hasmntopt(mntent, "clone_children"))
> + flags |= CGROUP_CLONE_CHILDREN;
> +
> + DEBUG("cgroup %s has flags 0x%x", mntent->mnt_dir, flags);
> + return flags;
> +}
> +
> static int get_cgroup_mount(const char *subsystem, char *mnt)
> {
> struct mntent *mntent;
> @@ -155,10 +170,12 @@ static int get_cgroup_mount(const char *subsystem,
> char *mnt)
> continue;
> if (!subsystem || hasmntopt_multiple(mntent, subsystem)) {
> int ret;
> - ret = snprintf(mnt, MAXPATHLEN, "%s%s/lxc",
> + int flags = get_cgroup_flags(mntent);
> + ret = snprintf(mnt, MAXPATHLEN, "%s%s%s",
> mntent->mnt_dir,
> get_init_cgroup(subsystem, NULL,
> - initcgroup));
> + initcgroup),
> + (flags & CGROUP_NS_CGROUP) ? "" :
> "/lxc");
> if (ret < 0 || ret >= MAXPATHLEN)
> goto fail;
> fclose(file);
> @@ -183,33 +200,26 @@ int lxc_ns_is_mounted(void)
> return (get_cgroup_mount("ns", buf) == 0);
> }
>
> -static int get_cgroup_flags(struct mntent *mntent)
> -{
> - int flags = 0;
> -
> -
> - if (hasmntopt(mntent, "ns"))
> - flags |= CGROUP_NS_CGROUP;
> -
> - if (hasmntopt(mntent, "clone_children"))
> - flags |= CGROUP_CLONE_CHILDREN;
> -
> - DEBUG("cgroup %s has flags 0x%x", mntent->mnt_dir, flags);
> - return flags;
> -}
> -
> static int cgroup_rename_nsgroup(const char *mnt, const char *name, pid_t
> pid)
> {
> char oldname[MAXPATHLEN];
> + char newname[MAXPATHLEN];
> + int ret;
> +
> + ret = snprintf(oldname, MAXPATHLEN, "%s/%d", mnt, pid);
> + if (ret >= MAXPATHLEN)
> + return -1;
>
> - snprintf(oldname, MAXPATHLEN, "%s/%d", mnt, pid);
> + ret = snprintf(newname, MAXPATHLEN, "%s/%s", mnt, name);
> + if (ret >= MAXPATHLEN)
> + return -1;
>
> - if (rename(oldname, name)) {
> - SYSERROR("failed to rename cgroup %s->%s", oldname, name);
> + if (rename(oldname, newname)) {
> + SYSERROR("failed to rename cgroup %s->%s", oldname,
> newname);
> return -1;
> }
>
> - DEBUG("'%s' renamed to '%s'", oldname, name);
> + DEBUG("'%s' renamed to '%s'", oldname, newname);
>
> return 0;
> }
> @@ -321,7 +331,7 @@ static int lxc_one_cgroup_create(const char *name,
> /* Do we have the deprecated ns_cgroup subsystem? */
> if (flags & CGROUP_NS_CGROUP) {
> WARN("using deprecated ns_cgroup");
> - return cgroup_rename_nsgroup(cgparent, cgname, pid);
> + return cgroup_rename_nsgroup(cginit, name, pid);
> }
>
> ret = snprintf(clonechild, MAXPATHLEN, "%s/cgroup.clone_children",
> @@ -464,9 +474,11 @@ int lxc_one_cgroup_destroy(struct mntent *mntent,
> const char *name)
> {
> char cgname[MAXPATHLEN], initcgroup[MAXPATHLEN];
> char *cgmnt = mntent->mnt_dir;
> + int flags = get_cgroup_flags(mntent);
>
> - snprintf(cgname, MAXPATHLEN, "%s%s/lxc/%s", cgmnt,
> - get_init_cgroup(NULL, mntent, initcgroup), name);
> + snprintf(cgname, MAXPATHLEN, "%s%s%s/%s", cgmnt,
> + get_init_cgroup(NULL, mntent, initcgroup),
> + (flags & CGROUP_NS_CGROUP) ? "" : "/lxc", name);
> DEBUG("destroying %s\n", cgname);
> if (recursive_rmdir(cgname)) {
> SYSERROR("failed to remove cgroup '%s'", cgname);
> diff --git a/src/lxc/lxc-ls.in b/src/lxc/lxc-ls.in
> index d200509..a1ad642 100644
> --- a/src/lxc/lxc-ls.in
> +++ b/src/lxc/lxc-ls.in
> @@ -33,7 +33,11 @@ if test -n "$active"; then
> if test -n "$mount_point"; then
> # get cgroup for init
> init_cgroup=`cat /proc/1/cgroup | awk -F: '{ print $3 }' |
> head -1`
> - cd $mount_point/$init_cgroup/lxc
> + if [ ! -d $mount_point/$init_cgroup/lxc ]; then
> + cd $mount_point/$init_cgroup
> + else
> + cd $mount_point/$init_cgroup/lxc
> + fi
> ls "$@" -d $active
> fi
> fi
> --
> 1.7.1
>
>
>
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