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From: Mike Fedyk <mfedyk@matchmail.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: Thu, 4 Dec 2003 13:48:50 -0800	[thread overview]
Message-ID: <20031204214850.GG29119@mis-mike-wstn.matchmail.com> (raw)
In-Reply-To: <200312041432.23907.rob@landley.net>

On Thu, Dec 04, 2003 at 02:32:23PM -0600, Rob Landley wrote:
> You can make a file with a hole by seeking past it and never writing to that 
> bit, but is there any way to punch a hole in a file after the fact?  (I mean 
> other with lseek and write.  Having a sparse file as the result....)
> 

No, Linux doesn't have this feature.

> What are the downsides of holes?  (How big do they have to be to actually save 
> space, is there a performance penalty to having a file with 1000 4k holes in 
> it, etc...)

When you copy them, you need to use tools that know about sparse files and
how to deal with them.  Also, you will only save space on block aligned
contiguous zeros at least the length of one block.

  parent reply	other threads:[~2003-12-04 21:49 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 [this message]
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
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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