From: Al Viro <viro@ZenIV.linux.org.uk>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Ian Kent <raven@themaw.net>
Subject: Re: [git pull] vfs fixes
Date: Mon, 3 Apr 2017 08:46:53 +0100 [thread overview]
Message-ID: <20170403074653.GN29622@ZenIV.linux.org.uk> (raw)
In-Reply-To: <87inmmvxlz.fsf@xmission.com>
On Mon, Apr 03, 2017 at 01:00:56AM -0500, Eric W. Biederman wrote:
> Refereshing my memory. d_automount mounts things and is what
> is used for nfs referrals. d_manage blocks waiting for
> an automounts to complete or expire. follow_down just calls d_manage,
> follow_manage calls both d_manage and d_automount as appropriate.
D'oh... Right. What's more, by that point getting back to original
state on error is needed.
> If the concern is nfs referral points calling follow_down is wrong and
> what is wanted is follow_managed.
... except that follow_managed() takes nameidata and there is no way in
hell we are letting that animal out of fs/namei.c ever again. Too low-level.
> The intent of the logic in mntns_install is to just pick a reasonable
> looking place somewhere in that mount namespace to use as a root
> directory. I arbitrarily picked the top of the mount stack on "/". Which
> is typically used as the root directory. If people really care where
> their root is they save a directory file descriptor off somewhere and
> call chroot. So there is a little wiggle room exactly what the code
> does.
Hmm... If anything, I'm tempted to add LOOKUP_DOWN that would have
path_lookupat() do
if (unlikely(flags & LOOKUP_DOWN)) {
struct path path = nd->path;
dget(nd->path.dentry);
err = follow_managed(&path, nd);
if (unlikely(err < 0))
terminate_walk(nd);
return err;
}
path_to_nameidate(&path, nd);
}
right after path_init(). Then your stuff would've turned into
get_mnt_ns(mnt_ns);
old_mnt_ns = nsproxy->mnt_ns;
nsproxy->mnt_ns = mnt_ns;
/* Find the root */
err = vfs_path_lookup(mnt_ns->root->mnt.mnt_root, &mnt_ns->root->mnt,
"/", LOOKUP_DOWN, &root);
if (err) {
/* revert to old namespace */
nsproxy->mnt_ns = old_mnt_ns;
put_mnt_ns(mnt_ns);
return err;
}
/* Update the pwd and root */
set_fs_pwd(fs, &root);
set_fs_root(fs, &root);
path_put(&root);
put_mnt_ns(old_mnt_ns);
return 0;
This is absolutely untested, and I won't get around to testing it until
tomorrow, but something along those lines would IMO be better than
exposing a trimmed-down follow_managed(), not to mention struct nameidata
itself...
next prev parent reply other threads:[~2017-04-03 7:46 UTC|newest]
Thread overview: 113+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-02 17:01 [git pull] vfs fixes Al Viro
2017-04-02 23:59 ` Linus Torvalds
2017-04-03 0:10 ` Linus Torvalds
2017-04-03 0:30 ` Al Viro
2017-04-03 0:43 ` Al Viro
2017-04-03 0:58 ` Linus Torvalds
2017-04-03 2:21 ` Al Viro
2017-04-03 6:00 ` Eric W. Biederman
2017-04-03 7:46 ` Al Viro [this message]
2017-04-04 0:22 ` Ian Kent
2017-04-04 0:47 ` Ian Kent
2017-04-03 0:20 ` Al Viro
-- strict thread matches above, loose matches on Subject: below --
2024-04-26 14:59 [GIT PULL] " Christian Brauner
2024-04-26 18:09 ` pr-tracker-bot
2024-04-05 11:22 Christian Brauner
2024-04-05 17:09 ` pr-tracker-bot
2024-03-18 12:19 Christian Brauner
2024-03-18 16:48 ` pr-tracker-bot
2024-03-18 19:14 ` Linus Torvalds
2024-03-18 19:41 ` Linus Torvalds
2024-03-19 6:58 ` Christian Brauner
2024-03-20 10:21 ` Christian Brauner
2024-03-06 15:45 Christian Brauner
2024-03-06 16:33 ` pr-tracker-bot
2024-03-01 12:45 Christian Brauner
2024-03-01 20:37 ` pr-tracker-bot
2024-02-22 14:03 Christian Brauner
2024-02-22 18:18 ` pr-tracker-bot
2024-02-12 13:00 Christian Brauner
2024-02-12 17:03 ` pr-tracker-bot
2024-01-13 12:31 Christian Brauner
2024-01-17 20:03 ` pr-tracker-bot
2023-11-24 10:27 Christian Brauner
2023-11-24 18:25 ` Linus Torvalds
2023-11-24 18:52 ` Linus Torvalds
2023-11-24 20:12 ` Linus Torvalds
2023-11-25 13:05 ` Christian Brauner
2023-11-25 13:10 ` Christian Brauner
2023-11-25 13:28 ` Omar Sandoval
2023-11-25 14:04 ` Christian Brauner
2023-11-24 18:26 ` pr-tracker-bot
2023-10-19 10:07 Christian Brauner
2023-10-19 16:37 ` Linus Torvalds
2023-10-20 11:14 ` Christian Brauner
2023-10-19 18:36 ` pr-tracker-bot
2023-09-26 10:39 Christian Brauner
2023-09-26 16:14 ` pr-tracker-bot
2023-07-06 11:52 Christian Brauner
2023-07-07 2:27 ` pr-tracker-bot
2023-07-02 11:28 Christian Brauner
2023-07-02 18:53 ` pr-tracker-bot
2023-05-25 12:22 Christian Brauner
2023-05-25 18:18 ` pr-tracker-bot
2023-05-12 15:31 Christian Brauner
2023-05-12 22:14 ` pr-tracker-bot
2023-04-03 11:04 Christian Brauner
2023-04-03 16:51 ` pr-tracker-bot
2023-03-12 12:18 Christian Brauner
2023-03-12 16:20 ` pr-tracker-bot
2020-09-22 21:29 [git pull] " Al Viro
2020-09-22 22:15 ` pr-tracker-bot
[not found] <CAHk-=wgdsv1UA+QtgiJM8KQAG7N7_9iK_edchnzZYyj+nxmfLA@mail.gmail.com>
[not found] ` <20200113195448.GT8904@ZenIV.linux.org.uk>
[not found] ` <CAHk-=whn5qk-e-KnYr6HNe5hp45v+XyDbsA2+szXvK3gC06A2w@mail.gmail.com>
2020-01-15 6:41 ` Al Viro
2020-01-15 19:35 ` pr-tracker-bot
2018-07-01 12:31 Al Viro
2018-07-01 19:36 ` Linus Torvalds
2018-07-01 20:05 ` Al Viro
2018-07-01 20:25 ` Linus Torvalds
2018-04-20 15:58 Al Viro
2018-04-20 18:29 ` Andrew Morton
2018-04-20 19:09 ` Al Viro
2018-04-20 19:57 ` Andrew Morton
2017-06-17 2:56 Al Viro
2017-04-09 5:40 Al Viro
2017-04-11 6:10 ` Linus Torvalds
2017-04-11 6:48 ` Al Viro
2017-04-11 21:02 ` Andreas Dilger
2017-04-12 7:00 ` Linus Torvalds
2017-04-15 6:41 ` Vegard Nossum
2017-04-15 16:51 ` Linus Torvalds
2017-04-15 17:08 ` Al Viro
2016-06-17 20:50 Q. hlist_bl_add_head_rcu() in d_alloc_parallel() J. R. Okajima
2016-06-17 22:16 ` Al Viro
2016-06-19 5:24 ` J. R. Okajima
2016-06-19 16:55 ` Al Viro
2016-06-20 4:34 ` J. R. Okajima
2016-06-20 5:35 ` Al Viro
2016-06-20 14:51 ` Al Viro
2016-06-20 17:14 ` [git pull] vfs fixes Al Viro
2016-06-08 2:12 Al Viro
2016-05-28 0:10 Al Viro
2016-02-28 1:09 Al Viro
2014-09-14 19:47 Al Viro
2014-09-26 20:38 ` Joachim Eastwood
2014-09-26 20:46 ` Joachim Eastwood
2014-09-26 20:58 ` Al Viro
2014-09-26 21:28 ` Joachim Eastwood
2014-09-26 21:52 ` Joachim Eastwood
2014-03-24 22:58 Imre Deak
2014-03-25 7:21 ` Sedat Dilek
2014-03-23 7:16 Al Viro
2014-03-23 10:57 ` Sedat Dilek
2014-03-23 15:35 ` Al Viro
2014-03-23 16:56 ` Al Viro
2014-03-23 16:36 ` Linus Torvalds
2014-03-23 16:45 ` Al Viro
2014-03-23 17:01 ` Linus Torvalds
2014-03-24 8:52 ` Sedat Dilek
2014-03-25 0:46 ` Linus Torvalds
2014-03-26 16:36 ` Sedat Dilek
2014-03-26 20:55 ` Linus Torvalds
2014-03-27 6:14 ` Sedat Dilek
2014-03-30 20:33 ` Al Viro
2014-03-30 20:55 ` Al Viro
2014-03-30 22:39 ` Linus Torvalds
2014-03-30 23:21 ` Al Viro
2013-06-22 7:16 Al Viro
2013-03-27 0:36 Al Viro
2012-03-10 21:30 Al Viro
2012-03-10 21:49 ` Linus Torvalds
2012-03-10 22:14 ` Al Viro
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