From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christoph Hellwig <hch@infradead.org>
Subject: Re: dm-thin f.req. : SEEK_DATA / SEEK_HOLE / SEEK_DISCARD
Date: Tue, 1 May 2012 09:08:16 -0400
Message-ID: <20120501130816.GA14067@infradead.org>
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On Tue, May 01, 2012 at 02:53:22PM +0200, Spelic wrote:
> Dear dm-thin developers,
> I thought that it would be immensely useful to have a SEEK_DATA /
> SEEK_HOLE implementation for dm-thin and/or even for the older
> non-thin snapshotting mechanism.

You can't implement it direct as device mapper doesn't implement the
file operations.  But I think adding block device operations that back
it would be a good idea, they could also implemented for arrays
implementing thin provisioning using the GET LBA STATUS scsi command.