linux-ext4 - Re: [PATCH 1/5] mbcache: correctly handle 'e

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: <20161203202838.ahd32zz3q7a5k4nr@thunk.org>
Date:   Sat, 3 Dec 2016 15:28:38 -0500
From:   Theodore Ts'o <tytso@....edu>
To:     Eric Biggers <ebiggers@...gle.com>
Cc:     linux-ext4@...r.kernel.org, Jan Kara <jack@...e.cz>,
        Andreas Gruenbacher <agruenba@...hat.com>
Subject: Re: [PATCH 1/5] mbcache: correctly handle 'e_referenced' bit

On Sat, Nov 26, 2016 at 10:17:57PM -0800, Eric Biggers wrote:
> mbcache entries have an 'e_referenced' bit which users can set with
> mb_cache_entry_touch() to indicate that an entry should be given another
> pass through the LRU list before the shrinker can delete it.  However,
> mb_cache_shrink() actually would, when seeing an e_referenced entry at
> the front of the list (the least-recently used end), place it right at
> the front of the list again.  The next iteration would then remove the
> entry from the list and delete it.  Consequently, e_referenced had
> essentially no effect, so ext2/ext4 xattr blocks would sometimes not be
> reused as often as expected.
> 
> Fix this by making the shrinker move e_referenced entries to the back of
> the list rather than the front.
> 
> Signed-off-by: Eric Biggers <ebiggers@...gle.com>

Thanks, applied.

					- Ted
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html