From: Tomas M <tomas@slax.org>
To: hooanon05@yahoo.co.jp
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC 2/8] Aufs2: structure
Date: Mon, 23 Feb 2009 10:13:11 +0100 [thread overview]
Message-ID: <49A268A7.1010708@slax.org> (raw)
In-Reply-To: <7769.1235374482@jrobl>
> 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
next prev parent reply other threads:[~2009-02-23 9:30 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-23 7:31 [RFC 0/8] Aufs2 documents hooanon05
2009-02-23 7:33 ` [RFC 1/8] Aufs2: introduction hooanon05
2009-02-23 7:34 ` [RFC 2/8] Aufs2: structure hooanon05
2009-02-23 9:13 ` Tomas M [this message]
2009-02-23 9:22 ` Tomas M
2009-02-24 8:13 ` New filesystem for Linux kernel Tomas M
2009-02-24 11:52 ` Miklos Szeredi
2009-02-24 13:18 ` hooanon05
2009-02-24 13:45 ` Tarkan Erimer
2009-02-24 13:57 ` hooanon05
2009-02-24 14:16 ` Tarkan Erimer
2009-02-24 14:50 ` Miklos Szeredi
2009-02-24 16:26 ` hooanon05
2009-02-25 10:28 ` Miklos Szeredi
2009-02-26 4:09 ` hooanon05
2009-02-26 5:51 ` hooanon05
2009-02-26 5:55 ` hooanon05
2009-02-24 14:15 ` Theodore Tso
2009-02-24 15:18 ` David P. Quigley
2009-02-24 15:41 ` hooanon05
2009-02-25 15:53 ` David P. Quigley
2009-02-26 4:21 ` hooanon05
2009-02-25 7:31 ` Tomas M
2009-02-25 9:33 ` David Newall
2009-02-25 8:12 ` Tomas M
2009-02-26 14:31 ` Amit Kucheria
2009-02-23 14:23 ` [RFC 2/8] Aufs2: structure hooanon05
2009-02-23 7:35 ` [RFC 3/8] Aufs2: lookup hooanon05
2009-02-23 7:36 ` [RFC 4/8] Aufs2: branch hooanon05
2009-02-23 7:36 ` [RFC 5/8] Aufs2: wbr_policy hooanon05
2009-02-23 7:37 ` [RFC 6/8] Aufs2: fmode_exec hooanon05
2009-02-23 7:37 ` [RFC 7/8] Aufs2: mmap hooanon05
2009-02-23 9:18 ` Tomas M
2009-02-23 14:39 ` hooanon05
2009-02-23 7:38 ` [RFC 8/8] Aufs2: plan hooanon05
2009-02-25 17:50 ` [RFC 0/8] Aufs2 documents David P. Quigley
2009-02-25 19:07 ` Matthew Wilcox
2009-02-26 4:54 ` hooanon05
2009-02-26 17:20 ` David P. Quigley
2009-02-27 14:27 ` hooanon05
2009-02-27 18:17 ` David P. Quigley
2009-02-28 8:04 ` hooanon05
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