linux-kernel - Re: page_mkwrite caller is racy?

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: <45BFEE7D.7060509@yahoo.com.au>
Date:	Wed, 31 Jan 2007 12:18:53 +1100
From:	Nick Piggin <nickpiggin@...oo.com.au>
To:	Anton Altaparmakov <aia21@....ac.uk>
CC:	Mark Fasheh <mark.fasheh@...cle.com>,
	Hugh Dickins <hugh@...itas.com>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	Linux Memory Management <linux-mm@...ck.org>,
	David Howells <dhowells@...hat.com>,
	Andrew Morton <akpm@...l.org>
Subject: Re: page_mkwrite caller is racy?

Anton Altaparmakov wrote:
> On Mon, 29 Jan 2007, Mark Fasheh wrote:
> 
>>
>>No page lock please. Generally, Ocfs2 wants to order cluster locks outside
>>of page locks. Also, the sparse b-tree support I'm working on right now will
>>need to be able to allocate in ->page_mkwrite() which would become very
>>nasty if we came in with the page lock - aside from the additional cluster
>>locks taken, ocfs2 will want to zero some adjacent pages (because we support
>>atomic allocation up to 1 meg).
> 
> 
> Ditto for NTFS.  I will need to lock pages on both sides of the page for 
> large volume cluster sizes thus I will have to drop the page lock if it is 
> already taken so it might as well not be...  Although I do not feel 
> strongly about it.  If the page is locked I will just drop the lock and 
> then take it again.  If possible to not have the page locked that would 
> make my code a little easier/more efficient I expect...

OK, that makes sense. Thanks to you both.

-- 
SUSE Labs, Novell Inc.
Send instant messages to your online friends http://au.messenger.yahoo.com 
-
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/