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From: Anthony Liguori <anthony@codemonkey.ws>
To: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] Re: qemu disk on vfat
Date: Mon, 08 May 2006 20:36:15 -0500	[thread overview]
Message-ID: <445FF20F.5070309@codemonkey.ws> (raw)
In-Reply-To: <20060508235024.GA18407@jbrown.mylinuxbox.org>

Jim C. Brown wrote:
> Aactually, the bug is in vfat not in qemu-img.
>   

Not really.  POSIX doesn't mandate that ftruncate() increase a file 
size.  This is a Linux-ism and is only valid for filesystems that 
support holes (which vfat doesn't).

Regards,

Anthony Liguori

> qemu-img correctly uses ftruncate() which is suppose to make the file sparse
> if the underlying filesystem supports it, but it should fall back to adding zeros
> to the end of the file. On vfat you aren't able to seek past the end of a file
> period, so this doesn't work.
>
> Probably qemu-img should just bail out in this case (as the other disk formats
> should work fine and you can always use dd). The 2nd patch I released does
> this - the error message just needs to be made more accurate.
>
>   

  reply	other threads:[~2006-05-09  1:36 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-05-08 10:04 [Qemu-devel] qemu disk on vfat Yann Le Doaré
2006-05-07  8:44 ` André Braga
2006-05-08 10:41   ` Yann Le Doaré
2006-05-07 15:50     ` [Qemu-devel] " Alex
2006-05-07 11:00 ` [Qemu-devel] " NyOS
2006-05-07 13:47   ` Jernej Simončič
2006-05-08 19:44   ` Yann Le Doaré
2006-05-08 14:57     ` Jan Marten Simons
2006-05-09 21:05       ` Yann Le Doaré
2006-05-07 11:21 ` Johannes Schindelin
2006-05-08 21:12 ` [Qemu-devel] " Anthony Liguori
2006-05-09 23:41   ` Yann Le Doaré
2006-05-08 22:05     ` Michael McConnell
2006-05-08 22:48       ` Jim C. Brown
2006-05-08 23:10         ` Jim C. Brown
2006-05-08 23:50           ` Jim C. Brown
2006-05-09  1:36             ` Anthony Liguori [this message]
2006-05-09  2:11               ` Paul Brook
2006-05-16 17:21             ` Jim C. Brown
2006-05-08 22:23     ` Ian C. Blenke

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