* Li Zefan <lizf@xxxxxxxxxxxxxx> [2009-05-22 11:00:12]:
> Now we have 'stat' file in both memory and cpuacct subsystems. If we
> mount these 2 subsystems with option 'noprefix', the creation of 'stat'
> file for cpuacct will fail, but without any notificatin to the user.
>
> With this patch, we fail the mount/remount in this case.
>
> Signed-off-by: Li Zefan <lizf@xxxxxxxxxxxxxx>
> ---
> kernel/cgroup.c | 18 ++++++++++++++++--
> 1 files changed, 16 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/cgroup.c b/kernel/cgroup.c
> index a7267bf..eab83f7 100644
> --- a/kernel/cgroup.c
> +++ b/kernel/cgroup.c
> @@ -896,6 +896,7 @@ static int parse_cgroupfs_options(char *data,
> static int cgroup_remount(struct super_block *sb, int *flags, char *data)
> {
> int ret = 0;
> + unsigned long subsys_bits;
> struct cgroupfs_root *root = sb->s_fs_info;
> struct cgroup *cgrp = &root->top_cgroup;
> struct cgroup_sb_opts opts;
> @@ -914,12 +915,17 @@ static int cgroup_remount(struct super_block *sb, int *flags, char *data)
> goto out_unlock;
> }
>
> + subsys_bits = root->subsys_bits;
> ret = rebind_subsystems(root, opts.subsys_bits);
> if (ret)
> goto out_unlock;
>
> /* (re)populate subsystem files */
> - cgroup_populate_dir(cgrp);
> + ret = cgroup_populate_dir(cgrp);
> + if (ret) {
if (ret) means a failure right? So we rebind_subsystems to the older
subsys_bits? Could you please add a comment, the code can be misread.
> + rebind_subsystems(root, subsys_bits);
> + goto out_unlock;
> + }
>
> if (opts.release_agent)
> strcpy(root->release_agent_path, opts.release_agent);
> @@ -1122,9 +1128,13 @@ static int cgroup_get_sb(struct file_system_type *fs_type,
> BUG_ON(!list_empty(&root_cgrp->children));
> BUG_ON(root->number_of_cgroups != 1);
>
> - cgroup_populate_dir(root_cgrp);
> + ret = cgroup_populate_dir(root_cgrp);
> +
> mutex_unlock(&inode->i_mutex);
> mutex_unlock(&cgroup_mutex);
> +
> + if (ret)
> + goto drop_new_super;
> }
>
> simple_set_mnt(mnt, sb);
> @@ -1803,6 +1813,10 @@ int cgroup_add_file(struct cgroup *cgrp,
> dput(dentry);
> } else
> error = PTR_ERR(dentry);
> +
> + if (error)
> + printk(KERN_WARNING "cgroup: Failed to create file '%s': %d\n",
> + name, error);
> return error;
> }
>
Looks good, should we mark cgroup_populate_dir with __must_check?
--
Balbir
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