From patchwork Wed May 30 14:58:56 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [02/12] container quota: lock/unlock mount namespace when performing quotactl. Date: Wed, 30 May 2012 04:58:56 -0000 From: "jeff.liu" X-Patchwork-Id: 161991 Message-Id: <1338389946-13711-3-git-send-email-jeff.liu@oracle.com> To: containers@lists.linux-foundation.org Cc: cgroups@vger.kernel.org, jack@suse.cz, glommer@parallels.com, daniel.lezcano@free.fr, tytso@mit.edu, bpm@sgi.com, chris.mason@oracle.com, hch@infradead.org, christopher.jones@oracle.com, david@fromorbit.com, tinguely@sgi.com, tm@tao.ma, linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, Jie Liu Introduce two functions to lock/unlock a particular mount namespace when container quota operations is performed. Signed-off-by: Jie Liu --- fs/namespace.c | 17 +++++++++++++++++ include/linux/mnt_namespace.h | 13 +++++++++++++ 2 files changed, 30 insertions(+), 0 deletions(-) diff --git a/fs/namespace.c b/fs/namespace.c index e608199..8823ba8 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -2633,3 +2633,20 @@ bool our_mnt(struct vfsmount *mnt) { return check_mnt(real_mount(mnt)); } + +/* + * Lock the mount namespace when performing a particular container + * disk quotactl operation, especially to protect removing it. + */ +void lock_mnt_ns(struct mnt_namespace *ns) +{ + down_write(&namespace_sem); +} + +/* + * Unlock the mount namespace after quotactl on that was done. + */ +void unlock_mnt_ns(struct mnt_namespace *ns) +{ + up_write(&namespace_sem); +} diff --git a/include/linux/mnt_namespace.h b/include/linux/mnt_namespace.h index 5a8e390..ff72ed5 100644 --- a/include/linux/mnt_namespace.h +++ b/include/linux/mnt_namespace.h @@ -9,6 +9,19 @@ extern struct mnt_namespace *copy_mnt_ns(unsigned long, struct mnt_namespace *, struct fs_struct *); extern void put_mnt_ns(struct mnt_namespace *ns); +#ifdef CONFIG_NS_QUOTA +extern void lock_mnt_ns(struct mnt_namespace *); +extern void unlock_mnt_ns(struct mnt_namespace *); +#else +void lock_mnt_ns(struct mnt_namespace *) +{ +} + +void unlock_mnt_ns(struct mnt_namespace *) +{ +} +#endif + extern const struct file_operations proc_mounts_operations; extern const struct file_operations proc_mountinfo_operations; extern const struct file_operations proc_mountstats_operations;