From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org (Eric W. Biederman) Subject: [REVIEW][PATCH 3/4] vfs: Add a function to lazily unmount all mounts from any dentry. v3 Date: Tue, 15 Oct 2013 13:17:55 -0700 Message-ID: <871u3mxp8s.fsf_-_@xmission.com> References: <8761v7h2pt.fsf@tw-ebiederman.twitter.com> <87li281wx6.fsf_-_@xmission.com> <87a9ioo37a.fsf_-_@xmission.com> <20131007043919.GB10284@mail.hallyn.com> <87vc191sf2.fsf@xmission.com> <87d2ngyb02.fsf@xmission.com> <20131008160601.GJ14242@tucsk.piliscsaba.szeredi.hu> <20131008161135.GK14242@tucsk.piliscsaba.szeredi.hu> <87li23trll.fsf@tw-ebiederman.twitter.com> <87vc15mjuw.fsf@xmission.com> <87iox38fkv.fsf@xmission.com> <87d2nb8dxy.fsf@xmission.com> <87iowyxpci.fsf_-_@xmission.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Linux Containers , Kernel Mailing List , Andy Lutomirski , Al Viro , Linux-Fsdevel , Matthias Schniedermeyer , Linus Torvalds To: Miklos Szeredi Return-path: In-Reply-To: <87iowyxpci.fsf_-_-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org> (Eric W. Biederman's message of "Tue, 15 Oct 2013 13:15:41 -0700") 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-fsdevel.vger.kernel.org v2: Always drop the lock when exiting early. v3: Make detach_mounts robust about freeing several mounts on the same mountpoint at one time, and remove the unneeded mnt_list list test. Signed-off-by: Eric W. Biederman --- fs/mount.h | 1 + fs/namespace.c | 24 ++++++++++++++++++++++++ 2 files changed, 25 insertions(+), 0 deletions(-) diff --git a/fs/mount.h b/fs/mount.h index e4342b8dfab1..7a6a2bb3f290 100644 --- a/fs/mount.h +++ b/fs/mount.h @@ -79,6 +79,7 @@ static inline int is_mounted(struct vfsmount *mnt) } extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *, int); +extern void detach_mounts(struct dentry *dentry); static inline void get_mnt_ns(struct mnt_namespace *ns) { diff --git a/fs/namespace.c b/fs/namespace.c index e4fe22c23e00..78f7c5c9e673 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1295,6 +1295,30 @@ static int do_umount(struct mount *mnt, int flags) return retval; } +void detach_mounts(struct dentry *dentry) +{ + struct mountpoint *mp; + struct mount *mnt; + + namespace_lock(); + if (!d_mountpoint(dentry)) + goto out_unlock; + + mp = new_mountpoint(dentry); + if (IS_ERR(mp)) + goto out_unlock; + + br_write_lock(&vfsmount_lock); + while (!list_empty(&mp->m_list)) { + mnt = list_first_entry(&mp->m_list, struct mount, mnt_mp_list); + umount_tree(mnt, 1); + } + br_write_unlock(&vfsmount_lock); + put_mountpoint(mp); +out_unlock: + namespace_unlock(); +} + /* * Is the caller allowed to modify his namespace? */ -- 1.7.5.4