linux-kernel - Re: [RFC 2/8] Aufs2: structure

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: <49A268A7.1010708@slax.org>
Date:	Mon, 23 Feb 2009 10:13:11 +0100
From:	Tomas M <tomas@...x.org>
To:	hooanon05@...oo.co.jp
CC:	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC 2/8] Aufs2: structure

> The struct of a xino file is simple, just a sequence of aufs inode
> numbers which is indexed by the lower inode number.
> In the above sample, assume the inode number of /ro/fileA is i111 and
> aufs assigns the inode number i999 for fileA. Then aufs writes 999 as
> 4(8) bytes at 111 * 4(8) bytes offset in the xino file.

I think it is worth mentioning that the xino file, if I understand it correctly, is a 'sparse file', that means it is full of 'holes' and doesn't consume as much disk space as it might appear.

In my opinion, the current xino-file approach is not much usable on filesystems which do not support sparse files (for example, if you wish to union two vfats), since some 'seeks' would probably write a lot of nulls. But I am not any kernel developer so I don't even know if there exists any filesystem which would be unable to support sparse files (except the mentioned VFAT, of course).

Tomas M
slax.org

--
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/