Re: [Xen-devel] [PATCH v2] fix Remus failover regression

[Shriram Rajagopalan <rshriram@xxxxxxxxx>]

On Jul 28, 2014 12:03 AM, "Yang Hongyang" <yanghy@xxxxxxxxxxxxxx> wrote:
>
> commit: c2ba706c
> tools/libxc: goto correct label on error paths by Andrew Cooper
> broke Remus in Xen 4.4 or earlier versions that has this commit
> backported.
>
> With Remus, this jump essentially discards the current incomplete
> checkpoint received by the backup and restore backup from the
> last complete checkpoint.
> This is required for Remus to work and this does not break live
> migration.
> It has been around since Xen 4.0.
>
> CC: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
> CC: Ian Campbell <ian.campbell@xxxxxxxxxx>
> CC: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> CC: Shriram Rajagopalan <rshriram@xxxxxxxxx>
> Signed-off-by: Yang Hongyang <yanghy@xxxxxxxxxxxxxx>
> ---
> Âtools/libxc/xc_domain_restore.c | 13 +++++++++++--
> Â1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/tools/libxc/xc_domain_restore.c b/tools/libxc/xc_domain_restore.c
> index e73e0a2..b9a56d5 100644
> --- a/tools/libxc/xc_domain_restore.c
> +++ b/tools/libxc/xc_domain_restore.c
> @@ -1783,20 +1783,29 @@ int xc_domain_restore(xc_interface *xch, int io_fd, uint32_t dom,
>
> Â Â Âif ( pagebuf_get(xch, ctx, &pagebuf, io_fd, dom) ) {
> Â Â Â Â ÂPERROR("error when buffering batch, finishing");
> - Â Â Â Âgoto out;
> + Â Â Â Â/*
> + Â Â Â Â * Remus: discard the current incomplete checkpoint and restore
> + Â Â Â Â * backup from the last complete checkpoint.
> + Â Â Â Â */
> + Â Â Â Âgoto finish;
> Â Â Â}
> Â Â Âmemset(&tmptail, 0, sizeof(tmptail));
> Â Â Âtmptail.ishvm = hvm;
> Â Â Âif ( buffer_tail(xch, ctx, &tmptail, io_fd, max_vcpu_id, vcpumap,
> Â Â Â Â Â Â Â Â Â Â Â ext_vcpucontext, vcpuextstate_size) < 0 ) {
> Â Â Â Â ÂERROR ("error buffering image tail, finishing");
> - Â Â Â Âgoto out;
> + Â Â Â Â/*
> + Â Â Â Â * Remus: discard the current incomplete checkpoint and restore
> + Â Â Â Â * backup from the last complete checkpoint.
> + Â Â Â Â */
> + Â Â Â Âgoto finish;
> Â Â Â}
> Â Â Âtailbuf_free(&tailbuf);
> Â Â Âmemcpy(&tailbuf, &tmptail, sizeof(tailbuf));
>
> Â Â Âgoto loadpages;
>
> + Â/* With Remus: restore from last complete checkpoint */
> Â Âfinish:
> Â Â Âif ( hvm )
> Â Â Â Â Âgoto finish_hvm;
> --
> 1.9.1
>

Acked-by: Shriram Rajagopalan <rshriram@xxxxxxxxx>

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