From: Vladimir Saveliev <vs@namesys.com>
To: Rob Landley <rob@landley.net>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Is there a "make hole" (truncate in middle) syscall?
Date: Fri, 12 Dec 2003 17:01:59 +0300 [thread overview]
Message-ID: <1071237719.27730.158.camel@tribesman.namesys.com> (raw)
In-Reply-To: <200312120753.11906.rob@landley.net>
On Fri, 2003-12-12 at 16:53, Rob Landley wrote:
> On Friday 12 December 2003 07:28, Vladimir Saveliev wrote:
> > Hi
> >
> > On Fri, 2003-12-12 at 15:55, Jörn Engel wrote:
> > > On Thu, 11 December 2003 14:32:12 -0600, Rob Landley wrote:
> > > > On Thursday 11 December 2003 13:48, Jörn Engel wrote:
> > > > > If you really do it, please don't add a syscall for it. Simply check
> > > > > each written page if it is completely filled with zero. (This will
> > > > > be a very quick check for most pages, as they will contain something
> > > > > nonzero in the first couple of words)
> > > >
> > > > Cache poisoning, streaming writes to large RAID arrays... There are
> > > > about 8 zllion reasons not to do this. Really. (It defeats the whole
> > > > purpose of DMA, doesn't it?)
> >
> > Sorry,
> > but doesn't truncate do almost exactly what "make hole" is supposed to
> > do?
>
> I have a 2 gigabyte file. I want to punch a hole from 257 megabytes to 364
> megabytes, saving over 100 megs of disk space. I do NOT want to have to copy
> off and rewrite 1.6 gigabytes of data from the end of the file. (There may
> not even be enough room on the disk, and it would take a long time anyway.)
>
ok.
But I asked why would "make hole" have problems you list (8 zillions)
and truncate would not have them?
> No, it doesn't do the same thing. Truncate is always to end of file. Punch
> hole is like a write, it takes a length. lseek(pos), punch(length).
>
> Rob
> -
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next prev parent reply other threads:[~2003-12-12 14:02 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-12-04 20:32 Is there a "make hole" (truncate in middle) syscall? Rob Landley
2003-12-04 20:55 ` Måns Rullgård
2003-12-04 21:10 ` Szakacsits Szabolcs
2003-12-05 0:02 ` Rob Landley
2003-12-04 22:33 ` Szakacsits Szabolcs
2003-12-05 11:22 ` Helge Hafting
2003-12-05 12:11 ` Måns Rullgård
2003-12-05 22:41 ` Mike Fedyk
2003-12-05 23:25 ` Måns Rullgård
2003-12-05 23:33 ` Szakacsits Szabolcs
2003-12-05 23:25 ` Szakacsits Szabolcs
2003-12-04 21:48 ` Mike Fedyk
2003-12-04 23:59 ` Rob Landley
2003-12-05 22:42 ` Olaf Titz
2003-12-04 22:53 ` Peter Chubb
2003-12-05 1:04 ` Philippe Troin
2003-12-05 2:39 ` Peter Chubb
2003-12-08 4:03 ` bill davidsen
2003-12-04 23:23 ` Andy Isaacson
2003-12-04 23:42 ` Szakacsits Szabolcs
2003-12-05 2:03 ` Mike Fedyk
2003-12-05 7:09 ` Ville Herva
2003-12-05 11:22 ` Anton Altaparmakov
2003-12-05 11:44 ` viro
2003-12-05 14:27 ` Anton Altaparmakov
2003-12-05 21:00 ` sparse file performance (was Re: Is there a "make hole" (truncate in middle) syscall?) Andy Isaacson
2003-12-05 21:12 ` Linus Torvalds
2003-12-08 20:43 ` Andy Isaacson
2003-12-11 5:13 ` Is there a "make hole" (truncate in middle) syscall? Hua Zhong
2003-12-11 6:19 ` Rob Landley
2003-12-11 18:58 ` Andy Isaacson
2003-12-11 19:15 ` Hua Zhong
2003-12-11 19:43 ` Andreas Dilger
2003-12-12 21:37 ` Daniel Phillips
2003-12-11 19:48 ` Jörn Engel
2003-12-11 19:55 ` Hua Zhong
2003-12-11 19:58 ` Andy Isaacson
2003-12-12 12:18 ` Jörn Engel
2003-12-12 15:40 ` Andy Isaacson
2003-12-12 16:03 ` Jörn Engel
2003-12-11 20:32 ` Rob Landley
2003-12-12 12:55 ` Jörn Engel
2003-12-12 13:28 ` Vladimir Saveliev
2003-12-12 13:43 ` Jörn Engel
2003-12-12 13:52 ` Vladimir Saveliev
2003-12-12 14:04 ` Jörn Engel
2003-12-12 13:53 ` Rob Landley
2003-12-12 14:01 ` Vladimir Saveliev [this message]
2003-12-12 21:35 ` Rob Landley
2003-12-15 10:00 ` Vladimir Saveliev
2003-12-15 11:52 ` Rob Landley
2003-12-15 13:26 ` Jörn Engel
2003-12-12 13:39 ` Rob Landley
2003-12-12 13:56 ` Jörn Engel
2003-12-12 14:24 ` Jörn Engel
2003-12-12 21:37 ` Rob Landley
2003-12-15 12:47 ` Jörn Engel
2003-12-16 5:43 ` Rob Landley
2003-12-16 11:05 ` Jörn Engel
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