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: <20080519004955.GD8335@mit.edu>
Date:	Sun, 18 May 2008 20:49:55 -0400
From:	Theodore Tso <tytso@....EDU>
To:	Stefano Fedrigo <aleph@...eler.com>
Cc:	Bernie Innocenti <bernie@...ewiz.org>,
	lkml <linux-kernel@...r.kernel.org>,
	David Woodhouse <dwmw2@...radead.org>, ext3-users@...hat.com,
	ext2-devel@...ts.sourceforge.net
Subject: Re: ext3_dx_add_entry: Directory index full!

On Mon, May 19, 2008 at 01:01:57AM +0200, Stefano Fedrigo wrote:
>
> So, if I understand correctly, with a 1024 bytes blocksize, dir_index, and 
> inode size of 128 byte, the maximum number of files in a directory is 
> 123008.  With 4k blocks this limit rises to 8,258,048 files?

It depends on the length of the directory entries, and how full the
various directory blocks end up getting (which is a function of the
directory names used and the per-filesystem hash seed).  But in
general, the maximum limit goes up as the cube of the blocksize.  So a
4k filesystem can store roughly 64 times as many files ; a filesystem
using 16k blocks (say, on a Power or IA64 architecture) will be able
to store roughly 4,096 as many files in a single directory.  (So
around 819 million files in a single directory, using the original
maildir example).

Seriously, though, past a certain point, if you really want to store
that many small datums, you should really consider a database....

     	  		    	   	  - 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/