From: jeff.liu-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org Subject: [PATCH 02/12] container quota: lock/unlock mount namespace when performing quotactl. Date: Wed, 30 May 2012 22:58:56 +0800 Message-ID: <1338389946-13711-3-git-send-email-jeff.liu@oracle.com> References: <1338389946-13711-1-git-send-email-jeff.liu@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: tytso-3s7WtUTddSA@public.gmane.org, jack-AlSwsSmVLrQ@public.gmane.org, david-FqsqvQoI3Ljby3iVrkZq2A@public.gmane.org, hch-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org, bpm-sJ/iWh9BUns@public.gmane.org, christopher.jones-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org, linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, tm-d1IQDZat3X0@public.gmane.org, linux-ext4-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, chris.mason-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org, tinguely-sJ/iWh9BUns@public.gmane.org To: containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Return-path: In-Reply-To: <1338389946-13711-1-git-send-email-jeff.liu-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org List-Id: linux-ext4.vger.kernel.org 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; -- 1.7.9