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From: Szakacsits Szabolcs <szaka@sienet.hu>
To: Chris Wedgwood <cw@f00f.org>
Cc: linux@horizon.com, linux-fsdevel@vger.kernel.org
Subject: Re: SEEK_HOLE and SEEK_DATA
Date: Fri, 3 Feb 2006 20:23:51 +0200 (MET DST)	[thread overview]
Message-ID: <Pine.LNX.4.61.0602032008580.16335@dhcppc0> (raw)
In-Reply-To: <20060203180821.GA4739@taniwha.stupidest.org>


On Fri, 3 Feb 2006, Chris Wedgwood wrote:
> On Thu, Feb 02, 2006 at 04:03:49AM -0500, linux@horizon.com wrote:
> 
> > Solaris 10 has added a moderately useful new feature...  lseek now
> > supports whence = 3 (SEEK_DATA) and 4 (SEEK_HOLE).  What these do is
> > advance the file pointer to the start of the next run of the
> > appropriate kind past the given (absolute) offset.
> 
> Some filesystems in linux (XFS for one, probably others?) already have
> a mechanism (albeit more complex the way it's exposed) to find holes &
> data.

NTFS, though not the Linux driver. Both XFS_IOC_GETBMAPX 
and FSCTL_QUERY_ALLOCATED_RANGE are much more efficient 
than SEEK_HOLE/SEEK_DATA (and let's forget about FIBMAP).

	Szaka

  reply	other threads:[~2006-02-03 18:26 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-02-02  9:03 SEEK_HOLE and SEEK_DATA linux
2006-02-03 18:08 ` Chris Wedgwood
2006-02-03 18:23   ` Szakacsits Szabolcs [this message]
2006-02-03 19:37     ` Chris Wedgwood
2006-02-03 22:00     ` Bryan Henderson
2006-02-03 23:41       ` Szakacsits Szabolcs
2006-02-03 23:53       ` Chris Wedgwood

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