From: Ingo Oeser <ingo.oeser@informatik.tu-chemnitz.de>
To: Bob McElrath <mcelrath+linux@draal.physics.wisc.edu>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Editing-in-place of a large file
Date: Sun, 2 Sep 2001 23:30:08 +0200 [thread overview]
Message-ID: <20010902233008.Q9870@nightmaster.csn.tu-chemnitz.de> (raw)
In-Reply-To: <20010902152137.L23180@draal.physics.wisc.edu>
In-Reply-To: <20010902152137.L23180@draal.physics.wisc.edu>; from mcelrath+linux@draal.physics.wisc.edu on Sun, Sep 02, 2001 at 03:21:37PM -0500
On Sun, Sep 02, 2001 at 03:21:37PM -0500, Bob McElrath wrote:
> I would like to take an extremely large file (multi-gigabyte) and edit
> it by removing a chunk out of the middle. This is easy enough by
> reading in the entire file and spitting it back out again, but it's
> hardly efficent to read in an 8GB file just to remove a 100MB segment.
>
> Is there another way to do this?
It's basically changing ownership (in terms of "which inode owns
which blocks") of blocks.
There is just no POSIX-API to do this, that's why there is no
simple way to do this.
Applications handling such large files usally implement a chunk
management, which can mark chunks as "unused" and skip them while
processing the file.
What's needed is a generalisation of sparse files and truncate().
They both handle similar problems.
For now I would seriously consider editing the ext2-structures
for this, because that's the only way you can do this right now.
Regards
Ingo Oeser
--
In der Wunschphantasie vieler Mann-Typen [ist die Frau] unsigned und
operatorvertraeglich. --- Dietz Proepper in dasr
next prev parent reply other threads:[~2001-09-02 21:30 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 ` Ingo Oeser [this message]
2001-09-03 0:59 ` Editing-in-place of a large file 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
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