[lxc-devel] [PATCH 1/1] cgroup: recursively delete cgroups when asked
S.Çağlar Onur
caglar at 10ur.org
Mon Jan 13 17:05:34 UTC 2014
Hi Serge,
On Mon, Jan 13, 2014 at 11:24 AM, Serge Hallyn <serge.hallyn at ubuntu.com> wrote:
> Quoting S.Çağlar Onur (caglar at 10ur.org):
>> Hey there,
>>
>> On Sun, Jan 12, 2014 at 7:24 PM, Stéphane Graber <stgraber at ubuntu.com> wrote:
>> > On Sat, Jan 11, 2014 at 12:14:26AM -0600, Serge Hallyn wrote:
>> >> Currently when a container is shut down, lxc walks the set of all
>> >> cgroup paths it created, in reverse order, and tries to remove them.
>> >> This doesn't suffice if the container has also created new cgroups.
>> >>
>> >> It'd be impolite to recursively remove all the cgroup paths we created,
>> >> since this can include '/lxc' and thereunder all other containers
>> >> started since.
>> >>
>> >> This patch changes container shutdown to only delete the container's own
>> >> path, but do so recursively. Note that if we fail during startup,
>> >> the container won't have created any cgroup paths so it the old
>> >> way works fine.
>> >>
>> >> Signed-off-by: Serge Hallyn <serge.hallyn at ubuntu.com>
>> >
>> > Acked-by: Stéphane Graber <stgraber at ubuntu.com>
>>
>> This patch started to cause my add_remove_device_node tests to fail
>> (rmdir started to return EBUSY), following seems to solve it but I'm
>> not sure whether it's a fix or just a workaround. Any ideas what might
>> be triggering that?
>
> Are you sure it was that patch? You can drop my patch and your
> test succeeds again?
Hmm you are right, after a git bisect it pointed following
df2d4205073d3f57543951ca7ffabf891b230634 is the first bad commit
commit df2d4205073d3f57543951ca7ffabf891b230634
Author: Dwight Engen <dwight.engen at oracle.com>
Date: Thu Jan 9 15:36:13 2014 -0500
ensure all config items are duplicated on clone/write_config
Since previously I had found a config item that wasn't being propagated
by lxc-clone, I went through all the config items and made sure that:
a) Each item is documented in lxc.conf
b) Each item is written out by write_config
The only one that isn't is lxc.include, which by its nature only pulls
in other config item types.
Signed-off-by: Dwight Engen <dwight.engen at oracle.com>
Acked-by: Serge E. Hallyn <serge.hallyn at ubuntu.com>
>> diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c
>> index 48fef74..80e68fb 100644
>> --- a/src/lxc/lxccontainer.c
>> +++ b/src/lxc/lxccontainer.c
>> @@ -2934,7 +2934,7 @@ static bool add_remove_device_node(struct
>> lxc_container *c, const char *src_path
>> ERROR("unlink failed");
>> goto out;
>> }
>> - if (rmdir(directory_path) < 0 && errno != ENOTEMPTY) {
>> + if (rmdir(directory_path) < 0 && errno != ENOTEMPTY &&
>> errno != EBUSY) {
>> ERROR("rmdir failed");
>> goto out;
>> }
>>
>>
>> >> ---
>> >> src/lxc/cgroup.c | 101 ++++++++++++++++++++++++++++++++++++++++++++++++-------
>> >> 1 file changed, 88 insertions(+), 13 deletions(-)
>> >>
>> >> diff --git a/src/lxc/cgroup.c b/src/lxc/cgroup.c
>> >> index b1196b4..be43c73 100644
>> >> --- a/src/lxc/cgroup.c
>> >> +++ b/src/lxc/cgroup.c
>> >> @@ -68,9 +68,9 @@ static char **subsystems_from_mount_options(const char *mount_options, char **ke
>> >> static void lxc_cgroup_mount_point_free(struct cgroup_mount_point *mp);
>> >> static void lxc_cgroup_hierarchy_free(struct cgroup_hierarchy *h);
>> >> static bool is_valid_cgroup(const char *name);
>> >> -static int create_or_remove_cgroup(bool remove, struct cgroup_mount_point *mp, const char *path);
>> >> +static int create_or_remove_cgroup(bool remove, struct cgroup_mount_point *mp, const char *path, int recurse);
>> >> static int create_cgroup(struct cgroup_mount_point *mp, const char *path);
>> >> -static int remove_cgroup(struct cgroup_mount_point *mp, const char *path);
>> >> +static int remove_cgroup(struct cgroup_mount_point *mp, const char *path, bool recurse);
>> >> static char *cgroup_to_absolute_path(struct cgroup_mount_point *mp, const char *path, const char *suffix);
>> >> static struct cgroup_process_info *find_info_for_subsystem(struct cgroup_process_info *info, const char *subsystem);
>> >> static int do_cgroup_get(const char *cgroup_path, const char *sub_filename, char *value, size_t len);
>> >> @@ -81,6 +81,75 @@ static int cgroup_recursive_task_count(const char *cgroup_path);
>> >> static int count_lines(const char *fn);
>> >> static int handle_cgroup_settings(struct cgroup_mount_point *mp, char *cgroup_path);
>> >>
>> >> +static int cgroup_rmdir(char *dirname)
>> >> +{
>> >> + struct dirent dirent, *direntp;
>> >> + int saved_errno = 0;
>> >> + DIR *dir;
>> >> + int ret, failed=0;
>> >> + char pathname[MAXPATHLEN];
>> >> +
>> >> + dir = opendir(dirname);
>> >> + if (!dir) {
>> >> + ERROR("%s: failed to open %s", __func__, dirname);
>> >> + return -1;
>> >> + }
>> >> +
>> >> + while (!readdir_r(dir, &dirent, &direntp)) {
>> >> + struct stat mystat;
>> >> + int rc;
>> >> +
>> >> + if (!direntp)
>> >> + break;
>> >> +
>> >> + if (!strcmp(direntp->d_name, ".") ||
>> >> + !strcmp(direntp->d_name, ".."))
>> >> + continue;
>> >> +
>> >> + rc = snprintf(pathname, MAXPATHLEN, "%s/%s", dirname, direntp->d_name);
>> >> + if (rc < 0 || rc >= MAXPATHLEN) {
>> >> + ERROR("pathname too long");
>> >> + failed=1;
>> >> + if (!saved_errno)
>> >> + saved_errno = -ENOMEM;
>> >> + continue;
>> >> + }
>> >> + ret = lstat(pathname, &mystat);
>> >> + if (ret) {
>> >> + SYSERROR("%s: failed to stat %s", __func__, pathname);
>> >> + failed=1;
>> >> + if (!saved_errno)
>> >> + saved_errno = errno;
>> >> + continue;
>> >> + }
>> >> + if (S_ISDIR(mystat.st_mode)) {
>> >> + if (cgroup_rmdir(pathname) < 0) {
>> >> + if (!saved_errno)
>> >> + saved_errno = errno;
>> >> + failed=1;
>> >> + }
>> >> + }
>> >> + }
>> >> +
>> >> + if (rmdir(dirname) < 0) {
>> >> + SYSERROR("%s: failed to delete %s", __func__, dirname);
>> >> + if (!saved_errno)
>> >> + saved_errno = errno;
>> >> + failed=1;
>> >> + }
>> >> +
>> >> + ret = closedir(dir);
>> >> + if (ret) {
>> >> + SYSERROR("%s: failed to close directory %s", __func__, dirname);
>> >> + if (!saved_errno)
>> >> + saved_errno = errno;
>> >> + failed=1;
>> >> + }
>> >> +
>> >> + errno = saved_errno;
>> >> + return failed ? -1 : 0;
>> >> +}
>> >> +
>> >> struct cgroup_meta_data *lxc_cgroup_load_meta()
>> >> {
>> >> const char *cgroup_use = NULL;
>> >> @@ -745,7 +814,7 @@ extern struct cgroup_process_info *lxc_cgroup_create(const char *name, const cha
>> >> * In that case, remove the cgroup from all previous hierarchies
>> >> */
>> >> for (j = 0, info_ptr = base_info; j < i && info_ptr; info_ptr = info_ptr->next, j++) {
>> >> - r = remove_cgroup(info_ptr->designated_mount_point, info_ptr->created_paths[info_ptr->created_paths_count - 1]);
>> >> + r = remove_cgroup(info_ptr->designated_mount_point, info_ptr->created_paths[info_ptr->created_paths_count - 1], false);
>> >> if (r < 0)
>> >> WARN("could not clean up cgroup we created when trying to create container");
>> >> free(info_ptr->created_paths[info_ptr->created_paths_count - 1]);
>> >> @@ -1039,8 +1108,7 @@ void lxc_cgroup_process_info_free_and_remove(struct cgroup_process_info *info)
>> >> if (!info)
>> >> return;
>> >> next = info->next;
>> >> - for (pp = info->created_paths; pp && *pp; pp++);
>> >> - for ((void)(pp && --pp); info->created_paths && pp >= info->created_paths; --pp) {
>> >> + {
>> >> struct cgroup_mount_point *mp = info->designated_mount_point;
>> >> if (!mp)
>> >> mp = lxc_cgroup_find_mount_point(info->hierarchy, info->cgroup_path, true);
>> >> @@ -1049,7 +1117,10 @@ void lxc_cgroup_process_info_free_and_remove(struct cgroup_process_info *info)
>> >> * '/lxc' cgroup in this container but another container
>> >> * is still running (for example)
>> >> */
>> >> - (void)remove_cgroup(mp, *pp);
>> >> + (void)remove_cgroup(mp, info->cgroup_path, true);
>> >> + }
>> >> + for (pp = info->created_paths; pp && *pp; pp++);
>> >> + for ((void)(pp && --pp); info->created_paths && pp >= info->created_paths; --pp) {
>> >> free(*pp);
>> >> }
>> >> free(info->created_paths);
>> >> @@ -1609,7 +1680,7 @@ bool is_valid_cgroup(const char *name)
>> >> return strcmp(name, ".") != 0 && strcmp(name, "..") != 0;
>> >> }
>> >>
>> >> -int create_or_remove_cgroup(bool do_remove, struct cgroup_mount_point *mp, const char *path)
>> >> +int create_or_remove_cgroup(bool do_remove, struct cgroup_mount_point *mp, const char *path, int recurse)
>> >> {
>> >> int r, saved_errno = 0;
>> >> char *buf = cgroup_to_absolute_path(mp, path, NULL);
>> >> @@ -1617,9 +1688,13 @@ int create_or_remove_cgroup(bool do_remove, struct cgroup_mount_point *mp, const
>> >> return -1;
>> >>
>> >> /* create or remove directory */
>> >> - r = do_remove ?
>> >> - rmdir(buf) :
>> >> - mkdir(buf, 0777);
>> >> + if (do_remove) {
>> >> + if (recurse)
>> >> + r = cgroup_rmdir(buf);
>> >> + else
>> >> + r = rmdir(buf);
>> >> + } else
>> >> + r = mkdir(buf, 0777);
>> >> saved_errno = errno;
>> >> free(buf);
>> >> errno = saved_errno;
>> >> @@ -1628,12 +1703,12 @@ int create_or_remove_cgroup(bool do_remove, struct cgroup_mount_point *mp, const
>> >>
>> >> int create_cgroup(struct cgroup_mount_point *mp, const char *path)
>> >> {
>> >> - return create_or_remove_cgroup(false, mp, path);
>> >> + return create_or_remove_cgroup(false, mp, path, false);
>> >> }
>> >>
>> >> -int remove_cgroup(struct cgroup_mount_point *mp, const char *path)
>> >> +int remove_cgroup(struct cgroup_mount_point *mp, const char *path, bool recurse)
>> >> {
>> >> - return create_or_remove_cgroup(true, mp, path);
>> >> + return create_or_remove_cgroup(true, mp, path, recurse);
>> >> }
>> >>
>> >> char *cgroup_to_absolute_path(struct cgroup_mount_point *mp, const char *path, const char *suffix)
>> >> --
>> >> 1.8.5.2
>> >>
>> >> _______________________________________________
>> >> lxc-devel mailing list
>> >> lxc-devel at lists.linuxcontainers.org
>> >> http://lists.linuxcontainers.org/listinfo/lxc-devel
>> >
>> > --
>> > Stéphane Graber
>> > Ubuntu developer
>> > http://www.ubuntu.com
>> >
>> > _______________________________________________
>> > lxc-devel mailing list
>> > lxc-devel at lists.linuxcontainers.org
>> > http://lists.linuxcontainers.org/listinfo/lxc-devel
>> >
>>
>>
>>
>> --
>> S.Çağlar Onur <caglar at 10ur.org>
>> _______________________________________________
>> lxc-devel mailing list
>> lxc-devel at lists.linuxcontainers.org
>> http://lists.linuxcontainers.org/listinfo/lxc-devel
> _______________________________________________
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> lxc-devel at lists.linuxcontainers.org
> http://lists.linuxcontainers.org/listinfo/lxc-devel
--
S.Çağlar Onur <caglar at 10ur.org>
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