Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754585Ab3JHN4H (ORCPT ); Tue, 8 Oct 2013 09:56:07 -0400 Received: from mail-ee0-f44.google.com ([74.125.83.44]:40661 "EHLO mail-ee0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753266Ab3JHN4D (ORCPT ); Tue, 8 Oct 2013 09:56:03 -0400 Date: Tue, 8 Oct 2013 15:56:48 +0200 From: Miklos Szeredi To: "Eric W. Biederman" Cc: "Serge E. Hallyn" , Al Viro , Linux-Fsdevel , Kernel Mailing List , Andy Lutomirski , Rob Landley , Linus Torvalds Subject: Re: [RFC][PATCH 2/3] vfs: Add a function to lazily unmount all mounts from any dentry. Message-ID: <20131008135648.GH14242@tucsk.piliscsaba.szeredi.hu> References: <87a9kkax0j.fsf@xmission.com> <8761v7h2pt.fsf@tw-ebiederman.twitter.com> <87li281wx6.fsf_-_@xmission.com> <87a9io1wu1.fsf_-_@xmission.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87a9io1wu1.fsf_-_@xmission.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2065 Lines: 70 On Fri, Oct 04, 2013 at 03:43:18PM -0700, Eric W. Biederman wrote: > > 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 d092964fe7f9..8eaee0c14fdb 100644 > --- a/fs/namespace.c > +++ b/fs/namespace.c > @@ -1294,6 +1294,30 @@ static int do_umount(struct mount *mnt, int flags) > return retval; > } > > +void detach_mounts(struct dentry *dentry) > +{ > + struct mount *mnt, *next; > + struct mountpoint *mp; > + > + namespace_lock(); > + if (!d_mountpoint(dentry)) { > + namespace_unlock(); > + return; > + } > + mp = new_mountpoint(dentry); > + if (IS_ERR(mp)) { > + return; > + } > + br_write_lock(&vfsmount_lock); > + list_for_each_entry_safe(mnt, next, &mp->m_list, mnt_mp_list) { I don't think list_for_each_entry_safe is actually safe enough here. Because propageted umounts will likely remove other mounts from the same mountpoint as well. Doing it with "while (!list_empty(&mp->m_list))" should be better, and AFAICS it will always make progress. > + if (!list_empty(&mnt->mnt_list)) > + umount_tree(mnt, 1); > + } > + br_write_unlock(&vfsmount_lock); > + put_mountpoint(mp); > + namespace_unlock(); > +} > + > /* > * Is the caller allowed to modify his namespace? > */ > -- > 1.7.5.4 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/