From: Jeff Layton <jlayton@kernel.org>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>,
Andrew Morton <akpm@linux-foundation.org>,
Mateusz Guzik <mjguzik@gmail.com>,
Josef Bacik <josef@toxicpanda.com>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] fs: try an opportunistic lookup for O_CREAT opens too
Date: Wed, 14 Aug 2024 07:48:17 -0400 [thread overview]
Message-ID: <df9ee1d9d34b07b9d72a3d8ee8d11c40cf07d193.camel@kernel.org> (raw)
In-Reply-To: <20240814024057.GP13701@ZenIV>
On Wed, 2024-08-14 at 03:40 +0100, Al Viro wrote:
> On Wed, Aug 14, 2024 at 03:18:17AM +0100, Al Viro wrote:
>
> > That's not the only problem; your "is it negative" test is inherently
> > racy in RCU mode. IOW, what is positive at the time you get here can
> > bloody well go negative immediately afterwards. Hit that with
> > O_CREAT and you've got a bogus ENOENT...
>
> Hmm... OTOH, in that case you end up in step_into(), which will do the
> right thing...
>
> How well does that series survive NFS client regression tests?
> That's where I'd expect potentially subtle shite, what with short-circuited
> ->d_revalidate() on the final pathwalk step in open()...
Christian took in my v3 patch which is a bit different from this one.
It seems to be doing fine in testing with NFS and otherwise.
I don't think we short-circuit the d_revalidate though, do we? That
version calls lookup_fast on the last component which should
d_revalidate the last dentry before returning it.
--
Jeff Layton <jlayton@kernel.org>
next prev parent reply other threads:[~2024-08-14 11:48 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-08-06 14:32 [PATCH v2] fs: try an opportunistic lookup for O_CREAT opens too Jeff Layton
2024-08-06 15:25 ` Mateusz Guzik
2024-08-06 16:17 ` Jeff Layton
2024-08-06 16:42 ` Mateusz Guzik
2024-08-06 19:11 ` Andi Kleen
2024-08-06 19:22 ` Mateusz Guzik
2024-08-06 20:42 ` Jeff Layton
2024-08-06 19:26 ` Jeff Layton
2024-08-06 20:03 ` Mateusz Guzik
2024-08-06 20:47 ` Andi Kleen
2024-08-15 15:07 ` Mateusz Guzik
2024-08-06 19:51 ` Jeff Layton
2024-08-14 2:18 ` Al Viro
2024-08-14 2:40 ` Al Viro
2024-08-14 11:48 ` Jeff Layton [this message]
2024-08-14 12:40 ` Christian Brauner
2024-08-14 15:44 ` Al Viro
2024-08-16 8:34 ` Christian Brauner
2024-08-14 15:42 ` Al Viro
2024-08-14 16:46 ` Jeff Layton
2024-08-07 14:26 ` Christian Brauner
2024-08-07 14:36 ` Jeff Layton
2024-08-08 10:36 ` Christian Brauner
2024-08-08 10:54 ` Jeff Layton
2024-08-08 11:18 ` Christian Brauner
2024-08-08 17:11 ` Jan Kara
2024-08-08 21:12 ` Paul Moore
2024-08-08 23:43 ` Jeff Layton
2024-08-09 0:28 ` Paul Moore
2024-08-09 0:33 ` Jeff Layton
2024-08-09 1:22 ` Paul Moore
2024-08-09 14:21 ` Jeff Layton
2024-08-11 21:52 ` Paul Moore
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