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Date: Tue, 9 Aug 2016 16:46:35 +0100
From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Message-ID: <20160809154635.GD2025@work-vm>
References: <1470702146-24399-1-git-send-email-liang.z.li@intel.com>
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In-Reply-To: <1470702146-24399-1-git-send-email-liang.z.li@intel.com>
Subject: Re: [Qemu-devel] [PATCH] migration: fix live migration failure with
 compression
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To: Liang Li <liang.z.li@intel.com>
Cc: qemu-devel@nongnu.org, quintela@redhat.com, amit.shah@redhat.com, berrange@redhat.com

* Liang Li (liang.z.li@intel.com) wrote:
> Because of commit 11808bb0c422, which remove some condition checks
> of 'f->ops->writev_buffer', 'qemu_put_qemu_file' should be enhanced
> to clear the 'f_src->iovcnt', or 'f_src->iovcnt' may exceed the
> MAX_IOV_SIZE which will break live migration. This should be fixed.
> 
> Signed-off-by: Liang Li <liang.z.li@intel.com>
> Reported-by: Jinshi Zhang <jinshi.c.zhang@intel.com>
> ---
>  migration/qemu-file.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/migration/qemu-file.c b/migration/qemu-file.c
> index bbc565e..e9fae31 100644
> --- a/migration/qemu-file.c
> +++ b/migration/qemu-file.c
> @@ -668,6 +668,7 @@ int qemu_put_qemu_file(QEMUFile *f_des, QEMUFile *f_src)
>          len = f_src->buf_index;
>          qemu_put_buffer(f_des, f_src->buf, f_src->buf_index);
>          f_src->buf_index = 0;
> +        f_src->iovcnt = 0;
>      }

If you're just using the buf[] in the src, how does it end up incrementing
the iovcnt?

Dave

>      return len;
>  }
> -- 
> 1.9.1
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK