Re: [Qemu-devel] [Qemu-block] [PATCH RFC v3 3/8] block: add throttle block filter driver

From: Manos Pitsidianakis <el13635@mail.ntua.gr>
To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: qemu-devel <qemu-devel@nongnu.org>, Kevin Wolf <kwolf@redhat.com>,
	Stefan Hajnoczi <stefanha@redhat.com>,
	qemu-block <qemu-block@nongnu.org>,
	Alberto Garcia <berto@igalia.com>
Subject: Re: [Qemu-devel] [Qemu-block] [PATCH RFC v3 3/8] block: add throttle block filter driver
Date: Mon, 26 Jun 2017 19:26:41 +0300	[thread overview]
Message-ID: <20170626162641.cavidsn7d67absxb@postretch> (raw)
In-Reply-To: <20170626143055.GC29664@stefanha-x1.localdomain>

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On Mon, Jun 26, 2017 at 03:30:55PM +0100, Stefan Hajnoczi wrote:
>> +    bs->file = bdrv_open_child(NULL, options, "file",
>> +                                    bs, &child_file, false, &local_err);
>> +
>> +    if (local_err) {
>> +        error_propagate(errp, local_err);
>> +        return -EINVAL;
>> +    }
>> +
>> +    qdict_flatten(options);
>> +    return throttle_configure_tgm(bs, tgm, options, errp);
>
>Who destroys bs->file on error?

It is reaped by bdrv_open_inherit() on failure, if I'm not mistaken.
That's how other drivers handle this as well. Some (eg block/qcow2.c)
check if bs->file is NULL instead of the error pointer they pass, so
this is not not very consistent.

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