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Re: [Qemu-devel] [PATCH] Add qerror message if the 'change' target filen
Re: [Qemu-devel] [PATCH] Add qerror message if the 'change' target filename can't be opened
Thu, 01 Apr 2010 21:14:30 +0200
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Am 01.04.2010 20:22, schrieb Luiz Capitulino:
> On Thu, 1 Apr 2010 15:15:51 -0300
> Luiz Capitulino <address@hidden> wrote:
>> On Thu, 25 Mar 2010 09:32:58 -0500
>> Ryan Harper <address@hidden> wrote:
>>> Currently when using the change command to switch the file in the cd drive
>>> the command doesn't complain if the file doesn't exit or can't be opened
>>> and the drive keeps the existing image. This patch adds a qerror_report
>>> call to print a message out indicating the failure. This error message
>>> can be used to catch failures.
>> Looks good to me, but it doesn't keep the existing image, it will silently
>> eject it instead.
> And, thinking more about it this seems the wrong behavior to me, if it
> fails to open the file, it should not touch the current one.
> Am I right, Kevin?
Well, it's a monitor command. I guess its meaning has never been clearly
defined, so I tend to say there is no right or wrong. From a user
perspective, intuitively I would expect that it succeeds completely or
maintains the old state, so yes.
However, I don't think it's fixable that easy. You obviously need to
close the image before you can open it. And reopening the image in case
of failure - well, we just had this discussion and I'm sure Juan wants
to comment on it...
It's a case that we should consider if/when we reorganize bdrv_open. The
"bdrv_close, but without closing the fd" thing doesn't work out here
because we need to reuse the same bs. Or maybe open a different bs first
and then copy things over. Could actually work this way.