linux-ext4 - Re: sparsify - utility to punch out blocks of 0s in a file

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Message-ID: <20120205172302.GA7057@citd.de>
Date:	Sun, 5 Feb 2012 18:23:02 +0100
From:	Matthias Schniedermeyer <ms@...d.de>
To:	Andreas Dilger <adilger@...ger.ca>
Cc:	Eric Sandeen <sandeen@...hat.com>,
	"linux-ext4@...r.kernel.org" <linux-ext4@...r.kernel.org>,
	Ron Yorston <rmy@...ress.co.uk>,
	"xfs@....sgi.com" <xfs@....sgi.com>
Subject: Re: sparsify - utility to punch out blocks of 0s in a file

On 05.02.2012 09:55, Andreas Dilger wrote:

> > Matthias' suggestion of adding SEEK_HOLE/SEEK_DATA makes very good sense too.
> 
> I thought about this, but if SEEK_HOLE/SEEK_DATA (or FIEMAP) worked, then the file would already be sparse, so I don't think that will help in this case...

With that argumentation you wouldn't need the tool in the first place.

"How can a bunch of zeros be in a file in the first place?"
"Can only be because of the deficiency of another program."

And who is to say that you wouldn't want to repeat such a thing from 
time to time, without SEEK_HOLE/SEEK_DATE you MAY crunch through big 
regions of zeros for no gain at all.



Bis denn

-- 
Real Programmers consider "what you see is what you get" to be just as 
bad a concept in Text Editors as it is in women. No, the Real Programmer
wants a "you asked for it, you got it" text editor -- complicated, 
cryptic, powerful, unforgiving, dangerous.

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