From: Daniel Phillips <phillips@bonn-fries.net>
To: Larry McVoy <lm@bitmover.com>,
Ingo Oeser <ingo.oeser@informatik.tu-chemnitz.de>
Cc: Bob McElrath <mcelrath+linux@draal.physics.wisc.edu>,
linux-kernel@vger.kernel.org
Subject: Re: Editing-in-place of a large file
Date: Mon, 3 Sep 2001 03:30:14 +0200 [thread overview]
Message-ID: <20010903012327Z16086-32383+3082@humbolt.nl.linux.org> (raw)
In-Reply-To: <20010902152137.L23180@draal.physics.wisc.edu> <20010902233008.Q9870@nightmaster.csn.tu-chemnitz.de> <20010902175938.D21576@work.bitmover.com>
In-Reply-To: <20010902175938.D21576@work.bitmover.com>
On September 3, 2001 02:59 am, Larry McVoy wrote:
> > What's needed is a generalisation of sparse files and truncate().
> > They both handle similar problems.
>
> how about
>
> fzero(int fd, off_t off, size_t len)
sys_clear :-)
> which zeros the blocks and if it can creates a holey file?
>
> However, that's not what Bob wants, he wants to remove commercials from
> recorded TV. So what he wants is
>
> fdelete(int fd, off_t off, size_t len)
>
> which has the semantics of shifting the rest of the file backwards to "off".
>
> The main problem with this is if the off/len are not block aligned. If they
> are, then this is just block twiddling, if they aren't, then this is a file
> rewrite anyway.
He could insert blank video frames to pad to the edges of blocks. Very
theoretical since we are ages away from having fzero/sys_clear. Ask Al Viro
if you want to hear the whole ugly story. (Executive summary: it's hard
enough handling remove/create races with just one boundary per file, now try
it with an unbounded number.)
--
Daniel
prev parent reply other threads:[~2001-09-03 1:23 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-09-02 20:21 Editing-in-place of a large file Bob McElrath
2001-09-02 21:28 ` COW fs (Re: Editing-in-place of a large file) VDA
2001-09-09 14:46 ` John Ripley
2001-09-09 16:30 ` John Ripley
2001-09-10 2:43 ` Daniel Phillips
2001-09-10 2:58 ` David Lang
2001-09-09 17:41 ` Xavier Bestel
2001-09-10 1:29 ` John Ripley
2001-09-10 6:45 ` Ragnar Kjørstad
2001-09-14 10:06 ` Pavel Machek
2001-09-10 11:11 ` Ihar Filipau
2001-09-10 16:10 ` Kari Hurtta
2001-09-14 10:03 ` Pavel Machek
2001-09-10 9:28 ` VDA
2001-09-10 9:35 ` John P. Looney
2001-09-02 21:30 ` Editing-in-place of a large file Ingo Oeser
2001-09-03 0:59 ` Larry McVoy
2001-09-03 1:24 ` Ingo Oeser
2001-09-03 1:31 ` Alan Cox
2001-09-03 1:50 ` Ingo Oeser
2001-09-03 10:48 ` Alan Cox
2001-09-03 14:31 ` Daniel Phillips
2001-09-03 14:46 ` Bob McElrath
2001-09-03 14:54 ` Alan Cox
2001-09-03 15:42 ` Doug McNaught
2001-09-03 15:11 ` Richard Guenther
2001-09-03 21:19 ` Ben Ford
2001-09-03 4:27 ` Bob McElrath
2001-09-03 1:30 ` Daniel Phillips [this message]
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