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Date: Tue, 22 May 2012 14:08:51 +0200
From: Kevin Wolf <kwolf@redhat.com>
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Subject: Re: [Qemu-devel] [RFC PATCH 0/4] block: file descriptor passing
 using -filefd and getfd_file
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To: Eric Blake <eblake@redhat.com>
Cc: libvir-list@redhat.com, aliguori@us.ibm.com, Corey Bryant <coreyb@linux.vnet.ibm.com>, qemu-devel@nongnu.org, stefanha@linux.vnet.ibm.com

Am 22.05.2012 14:02, schrieb Eric Blake:
> On 05/22/2012 02:18 AM, Kevin Wolf wrote:
> 
>>> This patch series adds the -filefd command-line option and the
>>> getfd_file monitor command.  This will enable libvirt to open a
>>> file and push the corresponding filename and file descriptor to
>>> QEMU.  When QEMU needs to "open" a file, it will first check if the
>>> file descriptor was passed by either of these methods before
>>> attempting to actually open the file.
>>
>> I thought we decided to avoid making some file names magic, and instead
>> go for the obvious /dev/fd/42?
> 
> This doesn't make "some file names magic", it makes "all file names
> magic".  In other words, _every_ call to open() first checks the
> database for an existing fd for the same file name.

Depends on your definition. You call every database lookup magic, I only
considered cases where the database actually contains something.

But no matter if "some" or "all", there's magic and I dislike that.

Kevin