Re: [Qemu-devel] [PATCH 1/3] block: Check for inserted BlockDriverState in blk_io_limits_disable()

From: Max Reitz <mreitz@redhat.com>
To: Alberto Garcia <berto@igalia.com>, qemu-devel@nongnu.org
Cc: qemu-block@nongnu.org, Stefan Hajnoczi <stefanha@redhat.com>,
	Kevin Wolf <kwolf@redhat.com>,
	sochin jiang <sochin.jiang@huawei.com>
Subject: Re: [Qemu-devel] [PATCH 1/3] block: Check for inserted BlockDriverState in blk_io_limits_disable()
Date: Fri, 10 Nov 2017 21:16:06 +0100	[thread overview]
Message-ID: <aacee0cf-d5bc-0279-da04-8d898dbc18a4@redhat.com> (raw)
In-Reply-To: <0d3a67ce8d948bb33e08672564714dcfb76a3d8c.1510339534.git.berto@igalia.com>

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On 2017-11-10 19:54, Alberto Garcia wrote:
> When you set I/O limits using block_set_io_throttle or the command
> line throttling.* options they are kept in the BlockBackend regardless
> of whether a BlockDriverState is attached to the backend or not.
> 
> Therefore when removing the limits using blk_io_limits_disable() we
> need to check if there's a BDS before attempting to drain it, else it
> will crash QEMU. This can be reproduced very easily using HMP:
> 
>      (qemu) drive_add 0 if=none,throttling.iops-total=5000
>      (qemu) drive_del none0
> 
> Reported-by: sochin jiang <sochin.jiang@huawei.com>
> Signed-off-by: Alberto Garcia <berto@igalia.com>
> ---
>  block/block-backend.c | 14 ++++++++++----
>  1 file changed, 10 insertions(+), 4 deletions(-)

Reviewed-by: Max Reitz <mreitz@redhat.com>


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