linux-kernel - Re: [PATCH 05/11] ext4: Make sure blocks are properly allocated under mmaped page even when blocksize

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 for Android: free password hash cracker in your pocket

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

Message-ID: <20090527143006.GC10842@mit.edu>
Date:	Wed, 27 May 2009 10:30:06 -0400
From:	Theodore Tso <tytso@....edu>
To:	Jan Kara <jack@...e.cz>
Cc:	LKML <linux-kernel@...r.kernel.org>, npiggin@...e.de,
	linux-ext4@...r.kernel.org,
	"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
Subject: Re: [PATCH 05/11] ext4: Make sure blocks are properly allocated
	under mmaped page even when blocksize < pagesize

On Wed, May 27, 2009 at 03:01:02PM +0200, Jan Kara wrote:
> In a situation like:
>   truncate(f, 1024);
>   a = mmap(f, 0, 4096);
>   a[0] = 'a';
>   truncate(f, 4096);
> 
> we end up with a dirty page which does not have all blocks allocated /
> reserved.  Fix the problem by using new VFS infrastructure.
> 
> Signed-off-by: Jan Kara <jack@...e.cz>

Hi Jan,

Have you tested with -o nodelalloc?  There is apparently a problem
with ext4 when blocksize < pagesize which Aneesh has been working on.
He has been able to reproduce the problem, and theorized that an
earlier version your patch set would address the problem, but it
apparently did not.  See:

	http://bugzilla.kernel.org/show_bug.cgi?id=13369

... and Aneesh can provide more details.  Aneesh, you might want to
try testing with this latest set and see if you can reproduce the
problem with this set.

						- Ted
--
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/