linux-kernel - Re: [PATCH 02/11] vfs: More precise tests in d

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CA+55aFyQntJjtVDJ1BsWGaPA5YY96ZjWJSxz-unjWU-RaQiFjw@mail.gmail.com>
Date:	Sat, 15 Feb 2014 16:03:53 -0800
From:	Linus Torvalds <torvalds@...ux-foundation.org>
To:	"Eric W. Biederman" <ebiederm@...ssion.com>
Cc:	Al Viro <viro@...iv.linux.org.uk>,
	"Serge E. Hallyn" <serge@...lyn.com>,
	Linux-Fsdevel <linux-fsdevel@...r.kernel.org>,
	Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Andy Lutomirski <luto@...capital.net>,
	Rob Landley <rob@...dley.net>,
	Miklos Szeredi <miklos@...redi.hu>,
	Christoph Hellwig <hch@...radead.org>,
	Karel Zak <kzak@...hat.com>,
	"J. Bruce Fields" <bfields@...ldses.org>
Subject: Re: [PATCH 02/11] vfs: More precise tests in d_invalidate

On Sat, Feb 15, 2014 at 3:23 PM, Eric W. Biederman
<ebiederm@...ssion.com> wrote:
>
> Except that today d_invalidate drops the dcache lock and
> calls shrink_dcache_parent.  Which gets you into exactly the same
> complex "walk parents and check all siblings" code.

Hmm. It only does that for directories that have sub-entries, though.

I think you may care just about directories (because that's what your
series is about), but d_invalidate() is used for other cases too,
notably d_revalidate() (ie things like stale NFS lookups of normal
files).

That said, I'll have to think about this more. If d_subdir is empty, I
guess d_walk() will be fairly cheap. It's very different, but maybe
not as disastrous as I thought.

                Linus
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/