From mboxrd@z Thu Jan  1 00:00:00 1970
From: Hubert Chan <hubert@uhoreg.ca>
Subject: Re: reiser4 plugins
Date: Wed, 06 Jul 2005 16:57:20 -0400
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In-Reply-To: <1120681998.13341.23.camel@localhost> (Jonathan Briggs's
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To: Jonathan Briggs <jbriggs@esoft.com>
Cc: "Alexander G. M. Smith" <agmsmith@rogers.com>, ross.biro@gmail.com, vonbrand@inf.utfsm.cl, mrmacman_g4@mac.com, Valdis.Kletnieks@vt.edu, ltd@cisco.com, gmaxwell@gmail.com, jgarzik@pobox.com, hch@infradead.org, akpm@osdl.org, linux-kernel@vger.kernel.org, reiserfs-list@namesys.com, zam@namesys.com, vs@thebsh.namesys.com, ndiller@namesys.com, ninja@slaphack.com, vitaly@thebsh.namesys.com

On Wed, 06 Jul 2005 14:33:18 -0600, Jonathan Briggs <jbriggs@esoft.com> said:

> On Wed, 2005-07-06 at 15:51 -0400, Hubert Chan wrote:
>> On Wed, 06 Jul 2005 12:52:23 -0600, Jonathan Briggs
>> <jbriggs@esoft.com> said:
> [snip]
>>> It still has the performance and locking problem of having to
>>> update every child file when moving a directory tree to a new
>>> parent.  On the other hand, maybe the benefit is worth the cost.

>> Every node should store the inode number(s) for its parent(s).  Not
>> the path name.  So you don't need to do any updates, since when you
>> move a tree, inode numbers don't change.

> You do need the updates if you change what inode is the parent.

> /a/b/c, /a/b/d, /a/b/e, /b
> mv /a/b /b
> Now you have to change the stored grand-parent inodes for /a/b/c,
> /a/b/d and /a/b/e so that they reference /b/b instead of /a/b.

Don't store (great)*grand-parent pointers; only parent pointers.  c
points to b, b points to a, a points to root.  c doesn't need to know
about /a or root directly.

-- 
Hubert Chan <hubert@uhoreg.ca> - http://www.uhoreg.ca/
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