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Date: Sun, 31 Dec 2000 02:02:34 +0100
From: Andrea Arcangeli <andrea@suse.de>
To: "Eric W. Biederman" <ebiederman@uswest.net>
Cc: Linus Torvalds <torvalds@transmeta.com>,
        Alexander Viro <viro@math.psu.edu>,
        Daniel Phillips <phillips@innominate.de>, linux-kernel@vger.kernel.org
Subject: Re: [RFC] Generic deferred file writing
Message-ID: <20001231020234.A15179@athlon.random>
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In-Reply-To: <m1u27lpo1g.fsf@frodo.biederman.org>; from ebiederman@uswest.net on Sat, Dec 30, 2000 at 03:00:43PM -0700
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On Sat, Dec 30, 2000 at 03:00:43PM -0700, Eric W. Biederman wrote:
> To get ENOSPC handling 99% correct all we need to do is decrement a counter,
> that remembers how many disks blocks are free.  If we need a better

Yes, we need to add one field to the in-core superblock to do this accounting.

> estimate than just the data blocks it should not be hard to add an
> extra callback to the filesystem.  

Yes, I was thinking at this callback too. Such a callback is nearly the only
support we need from the filesystem to provide allocate on flush. Allocate on
flush is a pagecache issue, not really a filesystem issue. When a filesystem
doesn't implement such callback we can simply get_block(create) at pagecache
creation time as usual.

Andrea
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