Re: [Xen-devel] [PATCH] [RFC] Fix RegEx Issues with xendomains for both SXP and JSON outputs of lx list -l

[Ian Murray <murrayie@xxxxxxxxxxx>]

----- Original Message -----
> From: Ian Campbell <Ian.Campbell@xxxxxxxxxx>
> To: Ian Murray <murrayie@xxxxxxxxxxx>
> Cc: George Dunlap <george.dunlap@xxxxxxxxxxxxx>; Joshua Tuttle 
> <jtuttle@xxxxxxxxx>; Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>; David Sutton 
> <kantras@xxxxxxxxx>; "xen-devel@xxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxx>
> Sent: Tuesday, 25 June 2013, 14:44
> Subject: Re: [Xen-devel] [PATCH] [RFC] Fix RegEx Issues with xendomains for
 both SXP and JSON outputs of lx list -l
> 
> On Tue, 2013-06-25 at 11:56 +0100, Ian Murray wrote:
>> 
>> 
>> 
>>  ----- Original Message -----
>>  > From: Ian Campbell <Ian.Campbell@xxxxxxxxxx>
>>  > To: Ian Murray <murrayie@xxxxxxxxxxx>
>>  > Cc: "xen-devel@xxxxxxxxxxxxx" 
> <xen-devel@xxxxxxxxxxxxx>; David Sutton <kantras@xxxxxxxxx>; Joshua 
> Tuttle <jtuttle@xxxxxxxxx>; George Dunlap 
> <george.dunlap@xxxxxxxxxxxxx>; Ian Jackson 
> <Ian.Jackson@xxxxxxxxxxxxx>
>>  > Sent: Tuesday, 25 June 2013, 10:40
>>  > Subject: Re: [PATCH] [RFC] Fix RegEx Issues with xendomains for both 
> SXP and
>>   JSON outputs of lx list -l
>>  > 
>>  > On Thu, 2013-06-20 at 13:00 +0100, Ian Murray wrote:
>>  >>  (Resent, as Yahoo seems to silently drop sentemail with the 
> subject
>>  >>  starting with a square open bracket. Space inserted - apologies 
> if
>>  >>  received more than once)
>>  > 
>>  > How very unhelpful of them! FWIW This seems to be the first one which
>>  > made it into the list archives as well as my INBOX.
>>  > 
>>  > I'm working through my post-vacation backlog this morning but I 
> hope to
>>  > have a chance to look at this vs. 4.3-rc soon since I think it is a
>>  > worthwhile bugfix for 4.3. George, what does your release 
> manager's hat
>>  > think?
>> 
>>  There are white space issues with this patch on this thread as it is,
>>  so I re-issued it more recently directly from git, as is the preferred
>>  method I think.
> 
> It's certainly less error prone. Do you have the message-id handy so I
> can find the right version?
> 

Date: Sat, 22 Jun 2013 13:38:11 +0100
Message-Id: <1371904691-9842-1-git-send-email-murrayie@xxxxxxxxxxx>


>>  As was suggested by David Sutton, there are probably more issues with
>>  this script than has been covered so far, but this change makes
>>  suspension and restoration work for me, at least. He suggests there
>>  are problems with zombies, etc.
> 
> You mean the handling of zombies by this script, rather than it somehow
> causing zombies?

Yes, handling of zombies.

> 
> Zombie domains are already themselves a bug in and of themselves so if
> that can be reproduced we'd like to hear about it, as for the script's
> handling of those zombies if/when they occur, I think it's probably
> something to deal with in 4.4.

This is something that David Sutton made comment on the original "users" 
thread. Without looking back, I seem to recall he'd spotted a bug in the 
xendomains script's handling rather than experiencing it. I have no experience 
of the issue. The reason for mentioning it was I just wanted to comment that my 
patch and testing wasn't a designed to fix all issues with xendomains, just the 
ones I had experience of. 

> 
>>  >>  Modifications to xendomains so that it correctly identifies a new 
> domain
>>  >>  entry when parsing the output of xl list -l. For both SXP and 
> JSON
>>  >>  outputs, it was failing to spot a new domain entry and was saving 
> the
>>  >>  second domain under a filename generated from the first 
> domain's name.
>>  >> 
>>  >>  I have listed this as RFC because although it is a patch against 
> 4.3RC5,
>>  >>  I have not had a chance to test against RC5, only 4.2.2. I 
> won't get an
>>  >>  opportunity until the weekend, so I invite comment and anybody to 
> give
>>  >>  it a test against RC5. Ian C has already commented elsewhere that 
> the xl
>>  >>  list -l JSON output has been altered between 4.2.x and 4.3RC5, so 
> this
>>  >>  might affect the indentation (the 4 spaces in the middle of the
>>  >>  LIST_GREP variable) - the trigger for new domain data is '    
> {' in 
>>  > JSON
>>  >>  version (in at least 4.2.2) and '(domain' in SXP version. 
> Not 
>>  > tested
>>  >>  against xm.
>>  >> 
>>  >>  It seems there is a problem in 4.2.2's implementation of SXP 
> output of
>>  >>  xl list -l in that all domain ID's are outputted as -1. Ian C 
> suggested
>>  >>  applying a change that originally went into 4.3 to resolve this 
> issue.
>>  >>  This seemed to do the trick (see thread [Xen-users] DomU
>>  >>  suspension/hibernation )
>>  > 
>>  > Would you be able to submit that backport as a patch against the 4.2
>>  > staging branch and CC myself and Ian Jackson
>>  > <ian.jackson@xxxxxxxxxxxxx> ?
>>  > 
>>  > This isn't a straight forward backport, since the majority of the 
> commit
>>  > is not a suitable candidate, but if you reference in the commit 
> message
>>  > the original commit id/subject and point out that only the one hunk is 
> a
>>  > useful bug fix which is why it's been split out then I think it 
> would be
>>  > fine to have in the next 4.2 release.
>> 
>>  I'll give this a go, but it will be a learning experience. I don't
>>  recall seeing any backporting info in the patch submission notes but I
>>  will take another look.
> 
> Thanks. It's not that common to have to do things this way (mostly we
> take the entire patch) so there isn't much in the way of docs. If you
> just treat it for the most part like a regular submission and explain
> what is going on in the commit message with references to the original
> commit ID and title then you won't go far wrong.
> 
>>   Who signs a (partial) backport off? Can't be me, because I didn't
>>  write it. Or can it? or is it copied from the original submission?
> 
> I think it would be appropriate to retain the original signed-off-by(s)
> and acks etc and append your own. Some people like to do:
> 
>   Commit message
> 
>   Signed-off-by: Original Author <original.author@xxxxxxxxxxx>
>   Acked-by: 
> 
>   Backported to X.Y
> 
>   Signed-off-by: Back Porter <bporter@xxxxxxxxxxx>
> 
> Or something like that, which is fine IMHO. Or if your commit message
> makes it clear enough what is going on then just tacking your S-o-b onto
> the original blocks of S-o-b's would be fine.
> 
> Ian J, does that sound about right? The issue is that one hunk of
> a73a7a0c647a "xl: Remove global domid and enable -Wshadow" is actually 
> a
> useful fix but the commit as a whole is large and unsuitable for
> backporting IMHO.
> 

Okay, will look into it.


> Ian.
> 
> 
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