From mboxrd@z Thu Jan  1 00:00:00 1970
From: Wen Congyang <wency@cn.fujitsu.com>
Subject: Re: [PATCH] fix Remus failover regression
Date: Mon, 28 Jul 2014 12:05:15 +0800
Message-ID: <53D5CBFB.30701@cn.fujitsu.com>
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To: Yang Hongyang <yanghy@cn.fujitsu.com>, xen-devel@lists.xen.org
Cc: Shriram Rajagopalan <rshriram@cs.ubc.ca>, Andrew Cooper <andrew.cooper3@citrix.com>, Ian Jackson <ian.jackson@eu.citrix.com>, Ian Campbell <ian.campbell@citrix.com>
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At 07/28/2014 11:35 AM, Yang Hongyang Write:
> commit: c2ba706c
> tools/libxc: goto correct label on error paths by Andrew broke
> Remus in Xen 4.4 or earlier versions that has this commit backported.
> 
> With Remus, this jump essentially discards the last incomplete
> checkpoint received by the backup.
> This is required for Remus to work and this does not break live
> migration.
> 
> CC: Ian Jackson <ian.jackson@eu.citrix.com>
> CC: Ian Campbell <ian.campbell@citrix.com>
> CC: Andrew Cooper <andrew.cooper3@citrix.com>
> CC: Shriram Rajagopalan <rshriram@cs.ubc.ca>
> Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
> ---
>  tools/libxc/xc_domain_restore.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/libxc/xc_domain_restore.c b/tools/libxc/xc_domain_restore.c
> index e73e0a2..5d2fbd6 100644
> --- a/tools/libxc/xc_domain_restore.c
> +++ b/tools/libxc/xc_domain_restore.c
> @@ -1783,14 +1783,14 @@ int xc_domain_restore(xc_interface *xch, int io_fd, uint32_t dom,
>  
>      if ( pagebuf_get(xch, ctx, &pagebuf, io_fd, dom) ) {
>          PERROR("error when buffering batch, finishing");
> -        goto out;
> +        goto finish;
>      }
>      memset(&tmptail, 0, sizeof(tmptail));
>      tmptail.ishvm = hvm;
>      if ( buffer_tail(xch, ctx, &tmptail, io_fd, max_vcpu_id, vcpumap,
>                       ext_vcpucontext, vcpuextstate_size) < 0 ) {
>          ERROR ("error buffering image tail, finishing");
> -        goto out;
> +        goto finish;
>      }
>      tailbuf_free(&tailbuf);
>      memcpy(&tailbuf, &tmptail, sizeof(tailbuf));
> 

The mail is here:
http://lists.xenproject.org/archives/html/xen-devel/2014-01/msg02299.html

> Both of these errors have been discovered by xc_domain_restore() returning
> success after suffering a fatal error during migration, leading to the
> toolstack believing that the VM migrated successfully.

These codes are only for Remus. So, why these codes are executed by migration?

Thanks
Wen Congyang