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 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 To: Miklos Szeredi Cc: Linux Containers , Kernel Mailing List , Andy Lutomirski , Al Viro , Linux-Fsdevel , Matthias Schniedermeyer , Linus Torvalds List-Id: containers.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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759898Ab3JOUSD (ORCPT ); Tue, 15 Oct 2013 16:18:03 -0400 Received: from out02.mta.xmission.com ([166.70.13.232]:59833 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759706Ab3JOUSB (ORCPT ); Tue, 15 Oct 2013 16:18:01 -0400 From: ebiederm@xmission.com (Eric W. Biederman) To: Miklos Szeredi Cc: Andy Lutomirski , "Serge E. Hallyn" , Al Viro , Linux-Fsdevel , Kernel Mailing List , Rob Landley , Linus Torvalds , Matthias Schniedermeyer , Linux Containers 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> Date: Tue, 15 Oct 2013 13:17:55 -0700 In-Reply-To: <87iowyxpci.fsf_-_@xmission.com> (Eric W. Biederman's message of "Tue, 15 Oct 2013 13:15:41 -0700") Message-ID: <871u3mxp8s.fsf_-_@xmission.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-AID: U2FsdGVkX1+lo7ZZcSe4F2uTc0F+qlM8uuR05IsVVZ0= X-SA-Exim-Connect-IP: 98.207.154.105 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 1.5 XMNoVowels Alpha-numberic number with no vowels * 1.5 TR_Symld_Words too many words that have symbols inside * 0.7 XMSubLong Long Subject * 0.0 T_TM2_M_HEADER_IN_MSG BODY: T_TM2_M_HEADER_IN_MSG * 0.8 BAYES_50 BODY: Bayes spam probability is 40 to 60% * [score: 0.4123] * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa06 1397; Body=1 Fuz1=1 Fuz2=1] * 0.0 T_TooManySym_01 4+ unique symbols in subject X-Spam-DCC: XMission; sa06 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: ***;Miklos Szeredi X-Spam-Relay-Country: Subject: [REVIEW][PATCH 3/4] vfs: Add a function to lazily unmount all mounts from any dentry. v3 X-Spam-Flag: No X-SA-Exim-Version: 4.2.1 (built Wed, 14 Nov 2012 14:26:46 -0700) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@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