Subject: Re: lseek() extension for spare files
To: Jason Thorpe <email@example.com>
From: Steven M. Bellovin <firstname.lastname@example.org>
Date: 09/21/2006 17:07:05
On Thu, 21 Sep 2006 13:51:28 -0700, Jason Thorpe <email@example.com>
> On Sep 20, 2006, at 6:44 PM, Reinoud Zandijk wrote:
> > Dear folks,
> > attached is a patch that implements the lseek() extension for sparse
> > files
> > as can be found in Solaris 10. Linux aparently has already
> > adopted/implented it also.
> > It adds the SEEK_DATA and SEEK_HOLE `whence' arguments to lseek().
> > For a
> > more detailed look see the solaris 10 man page :
> > http://tinyurl.com/fk6we
> So, it looks like these new whence arguments are essentially designed
> to enumerate the holes or filled regions of the file.
> I don't see anything particularly wrong with having it (note I have
> not yet reviewed the actual patch), but what's the application usage?
Copying and/or backing up large, sparse files.
--Steven M. Bellovin, http://www.cs.columbia.edu/~smb