linux-kernel - Re: ext3_dx_add_entry: Directory index full!

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: <20080518210435.GA8335@mit.edu>
Date:	Sun, 18 May 2008 17:04:35 -0400
From:	Theodore Tso <tytso@....EDU>
To:	bernie@...ewiz.org
Cc:	lkml <linux-kernel@...r.kernel.org>,
	David Woodhouse <dwmw2@...radead.org>, ext3-users@...hat.com,
	ext2-devel@...ts.sourceforge.net,
	Stefano Fedrigo <aleph@...eler.com>
Subject: Re: ext3_dx_add_entry: Directory index full!

On Sun, May 18, 2008 at 05:38:58PM +0200, Bernie Innocenti wrote:
> Bernie Innocenti wrote:
>> On 2.6.24.4-64.fc8, I createed and mounted a filesystem like this:
>>   mke2fs -m0 -b 1024 -R stride=64 -I 128 -i 2048 -j  -L mail -O 
>> dir_index,sparse_super -v /dev/sdc1
>
> I cannot reproduce it any more if I reformat omitting "-b 1024".
> Maybe it would reappear with 200K * 4 = 800K files?

Using a filesystem with 4k blocks, and assuming the filenames are of
the same average length, you should be able to get approximately 200k
* (4**3) = 12.8 million files in a single directory.  If you use a 2k
block filesystem, the limit will be approximately 200k * (2**3) = 1.6
million files in a single directory.

Regards,

						- Ted

P.S.  Past a certain point, you really don't want to have that many
files in a Maildir directory; if the user is never going to be
deleting his SPAM, then you should seriously think about using a Unix
mbox style storage scheme.  Even with a 1k block filesystem, at 12
million files you'll be wasting 6 gigabytes of disk space of slack
space that is totally being wasted since the whole point of using
Maildir is to make it easy to delete or replace individual mail
messages.  If you want to archive all of your SPAM, why use a Maildir
format mbox at all?
--
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/