linux-ext4 - Re: Large directories and poor order correlation

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]

Date:	Tue, 15 Mar 2011 07:59:21 +0000
From:	Florian Weimer <fweimer@....de>
To:	Eric Sandeen <sandeen@...hat.com>
Cc:	Phillip Susi <psusi@....rr.com>,
	"linux-ext4\@vger.kernel.org" <linux-ext4@...r.kernel.org>
Subject: Re: Large directories and poor order correlation

* Eric Sandeen:

> No, because htree (dir_index) dirs returns names in hash-value
> order, not inode number order.  i.e. "at random."
>
> As you say, sorting by inode number will work much better...

The dpkg folks tested this and it turns out that you get better
results if you open the file and use FIBMAP to get the first block
number, and sort by that.  You could sort by inode number before the
open/fstat calls, but it does not seem to help much.

-- 
Florian Weimer                <fweimer@....de>
BFK edv-consulting GmbH       http://www.bfk.de/
Kriegsstraße 100              tel: +49-721-96201-1
D-76133 Karlsruhe             fax: +49-721-96201-99
--
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