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From: Nikita Danilov <nikita@clusterfs.com>
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Date: Sun, 11 Jun 2006 20:30:57 +0400
To: Arjan van de Ven <arjan@infradead.org>
Cc: Matthew Frost <artusemrys@sbcglobal.net>, Alex Tomas <alex@clusterfs.com>,
       Linus Torvalds <torvalds@osdl.org>, Andrew Morton <akpm@osdl.org>,
       ext2-devel <ext2-devel@lists.sourceforge.net>,
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       linux-fsdevel@vger.kernel.org
Subject: Re: [Ext2-devel] [RFC 0/13] extents and 48bit ext3
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Arjan van de Ven writes:
 > On Fri, 2006-06-09 at 14:51 -0400, Jeff Garzik wrote:
 > > PRECISELY.  So you should stop modifying a filesystem whose design is 
 > > admittedly _not_ modern!
 > > 
 > > ext3 is already essentially xiafs-on-life-support, when you consider 
 > > today's large storage systems and today's filesystem technology.  Just 
 > > look at the ugly hacks needed to support expanding an ext3 filesystem 
 > > online.
 > 
 > 
 > actually I think I disagree with you. One thing I've noticed over the
 > years is that ext2 layout has one thing going for it: it is simple and
 > robust. Maybe "ext2 layout" is the wrong word, "block bitmap and
 > direct/indirect block based" may be better. It seems that once you go
 > into tree space (and I would call htree a borderline thing there) you
 > get both really complex code and fragile behavior all over (mostly in
 > terms of "when something goes wrong")

Huh? Direct/indirect/double-indirect/... _is_ a tree, albeit not
balanced one. What makes s5fs/ffs/ufs/ext* so exceptionally robust is
fixed position of inode tables, which provides a guaranteed starting
point for fsck under almost any circumstances.

Nikita.