Skip site navigation (1)Skip section navigation (2)
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>

next in thread | previous in thread | raw e-mail | index | archive | help
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



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20040720081051.GB3001>