Re: [Qemu-devel] [RFC V5 03/11] quorum: Add quorum_open() and quorum_close().

[Eric Blake <eblake@redhat.com>]

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On 08/27/2012 01:30 AM, Benoît Canet wrote:
> Valid quorum resources look like
> quorum:threshold/total:path/to/image_1, ... ,path/to/image_total
> 
> ',' is used as a separator to allow to use networked path

Isn't this a step backwards?  After all, on the command line, we would
have something like:

-drive file=quorum:...,readonly=on

but if the 'quorum:...' portion contains commas, then the qemu option
parsing requires you to write those commas as doubled.  Which means to
escape those commas for _both_ quorum: processing _and_ qemu command
line parsing, I'd have to write:

-drive "file=quorum:2/2:path/to/image\\,,1,,path/to/image\\\\2,readonly=on"

to use the two files:
path/to/image,1
path/to/image\2

with appropriate shell, qemu, and quorum escaping.  Using : rather than
, as the separator between quorum: elements was a bit simpler, since I
don't have to type double commas for every single comma to be taken by
the quorum parsing, escaped or not.

> '\' is the escaping character for filename containing ','
> '\' escape itself

s/escape/escapes/

> 
> On the command line for quorum files "img,test.raw", "img2.raw"
> and "img3.raw" invocation look like:
> 
> -drive file=quorum:2/3:img\\,,test.raw,,img2.raw,,img3.raw
> (note the double ,, and \\)

Yes, that's what I'm worried about.

-- 
Eric Blake   eblake@redhat.com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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