From: ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org (Eric W. Biederman)
To: Christoph Hellwig <hch-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
Cc: Miklos Szeredi <miklos-sUDqSbJrdHQHWmgEVkV9KA@public.gmane.org>,
Linux Containers
<containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>,
Kernel Mailing List
<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Andy Lutomirski <luto-kltTT9wpgjJwATOyAt5JVQ@public.gmane.org>,
Al Viro <viro-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>,
Linux-Fsdevel
<linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Matthias Schniedermeyer <ms-QGhoYOTWWTg@public.gmane.org>,
Linus Torvalds
<torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Subject: Re: [REVIEW][PATCH 1/4] vfs: Don't allow overwriting mounts in the current mount namespace
Date: Thu, 21 Nov 2013 12:58:44 -0800 [thread overview]
Message-ID: <878uwh8oaj.fsf@xmission.com> (raw)
In-Reply-To: <20131109084916.GA21413-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org> (Christoph Hellwig's message of "Sat, 9 Nov 2013 00:49:16 -0800")
Christoph Hellwig <hch-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org> writes:
> On Fri, Nov 08, 2013 at 02:17:31PM -0800, Eric W. Biederman wrote:
>> > Read what you've written a few lines above. The part about target->i_mutex
>> > being held.
>>
>> That works for the rename as unlink case but we don't hold
>> old_dentry->d_inode->i_mutex which is what is needed to prevent a mount
>> on the dentry we are renaming.
>
> It will be held in 3.13.
Only for files, not for directories. And none of those locks turns out
to be good enough today to prevent the races between mount and rename.
With the result that when mount returns your mount point could be
located just about anywhere, and that is just considering renames of the
actual mountpoint itself.
Eric
next prev parent reply other threads:[~2013-11-21 20:58 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <8761v7h2pt.fsf@tw-ebiederman.twitter.com>
[not found] ` <CAJfpegtT7y-1HhbEVAMKkdQugTG_w7G_epGtQHGvQLpcZB5FVA@mail.gmail.com>
[not found] ` <87li281wx6.fsf_-_@xmission.com>
[not found] ` <87a9ioo37a.fsf_-_@xmission.com>
[not found] ` <20131007043919.GB10284@mail.hallyn.com>
[not found] ` <87vc191sf2.fsf@xmission.com>
[not found] ` <CALCETrUaubASZyeoNZcYxn5-GJO68=Ng=GYmas7K_OBsjM7f0Q@mail.gmail.com>
[not found] ` <87d2ngyb02.fsf@xmission.com>
[not found] ` <20131008160601.GJ14242@tucsk.piliscsaba.szeredi.hu>
[not found] ` <CALCETrWw=htmgxqq=RQztdJQ-a8c3860vmJh9Ni=Hhs0TkO3YA@mail.gmail.com>
[not found] ` <20131008161135.GK14242@tucsk.piliscsaba.szeredi.hu>
[not found] ` <87li23trll.fsf@tw-ebiederman.twitter.com>
[not found] ` <CAJfpegv+h7xh_2e-X7is9dq1Fp06A0eKwsyWFMPX=azbbDCX5Q@mail.gmail.com>
[not found] ` <87vc15mjuw.fsf@xmission.com>
[not found] ` <CAJfpegvF89LzAvNB0h0otv7sKoS3rewZzQKAauQx3P+rCkCcSg@mail.gmail.com>
[not found] ` <87iox38fkv.fsf@xmission.com>
[not found] ` <87d2nb8dxy.fsf@xmission.com>
[not found] ` <87d2nb8dxy.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2013-10-15 20:15 ` [REVIEW][PATCH 0/4] vfs: Detach mounts on unlink Eric W. Biederman
[not found] ` <87iowyxpci.fsf_-_-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2013-10-15 20:16 ` [REVIEW][PATCH 1/4] vfs: Don't allow overwriting mounts in the current mount namespace Eric W. Biederman
2013-10-15 20:17 ` [REVIEW][PATCH 2/4] vfs: Keep a list of mounts on a mount point Eric W. Biederman
[not found] ` <877gdexp9s.fsf_-_-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2013-10-22 19:06 ` Serge E. Hallyn
2013-10-15 20:17 ` [REVIEW][PATCH 3/4] vfs: Add a function to lazily unmount all mounts from any dentry. v3 Eric W. Biederman
[not found] ` <871u3mxp8s.fsf_-_-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2013-10-22 19:08 ` Serge E. Hallyn
2013-10-15 20:18 ` [REVIEW][PATCH 4/4] vfs: Lazily remove mounts on unlinked files and directories. v2 Eric W. Biederman
[not found] ` <87vc0ywan7.fsf_-_-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2013-10-22 19:13 ` Serge E. Hallyn
[not found] ` <87d2n6xpan.fsf_-_@xmission.com>
[not found] ` <87d2n6xpan.fsf_-_-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2013-10-22 19:04 ` [REVIEW][PATCH 1/4] vfs: Don't allow overwriting mounts in the current mount namespace Serge E. Hallyn
2013-11-03 3:54 ` Al Viro
[not found] ` <20131103035406.GA8537@ZenIV.linux.org.uk>
[not found] ` <20131103035406.GA8537-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2013-11-08 20:51 ` Eric W. Biederman
[not found] ` <87bo1u8vmf.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2013-11-08 21:35 ` Al Viro
[not found] ` <20131108213551.GR13318@ZenIV.linux.org.uk>
[not found] ` <20131108213551.GR13318-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2013-11-08 22:17 ` Eric W. Biederman
[not found] ` <87fvr61qtg.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2013-11-09 8:49 ` Christoph Hellwig
[not found] ` <20131109084916.GA21413-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
2013-11-21 20:58 ` Eric W. Biederman [this message]
2013-11-21 20:49 ` Eric W. Biederman
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