Date: Tue, 20 Jul 2004 18:10:51 +1000 From: Peter Jeremy <PeterJeremy@optushome.com.au> To: Tim Kientzle <tim@kientzle.com> Cc: current@freebsd.org Subject: Re: NEW TAR Message-ID: <20040720081051.GB3001@cirb503493.alcatel.com.au> In-Reply-To: <40FC9FC2.8050400@kientzle.com> References: <40F963D8.6010201@freebsd.org> <20040719060730.GA87697@nagual.pp.ru> <40FC9FC2.8050400@kientzle.com>
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On Mon, 2004-Jul-19 21:29:54 -0700, Tim Kientzle wrote: >I have some ideas about sparse file handling, >but they're not gtar-compatible. (The gtar >approach has a number of drawbacks. The primary >one being that on many systems it requires reading >the entire file twice, once to find holes and again >to actually archive the file. Actually, it's not possible to accurately determine the holes in a file by reading it - you can't differentiate between a hole and a allocated block of zeroes. What you need is a (new) syscall that invokes a new VOP_... and returns a bitmap of allocated blocks. This would be non-trival unfortunately. -- Peter Jeremy
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