qemu-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Qemu-devel] [PATCH] nbd: wait all read/write requests finished when


From: Wen Congyang
Subject: Re: [Qemu-devel] [PATCH] nbd: wait all read/write requests finished when shutdowning nbd socket
Date: Wed, 16 Sep 2015 16:22:59 +0800
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0

On 09/16/2015 04:17 PM, Paolo Bonzini wrote:
> 
> 
> On 16/09/2015 09:16, Wen Congyang wrote:
>> If the socket fd is shutdown, there may be some data which is received before
>> shutdown. We will read the data and do read/write in nbd_trip(). But the 
>> exp's
>> blk is NULL, and it will cause qemu crashed.
>>
>> Reported-by: Li Zhijian <address@hidden>
>> Signed-off-by: Wen Congyang <address@hidden>
>> ---
>>  nbd.c | 9 +++++++++
>>  1 file changed, 9 insertions(+)
>>
>> diff --git a/nbd.c b/nbd.c
>> index 06b501b..d8586a1 100644
>> --- a/nbd.c
>> +++ b/nbd.c
>> @@ -1132,6 +1132,7 @@ void nbd_export_close(NBDExport *exp)
>>      nbd_export_set_name(exp, NULL);
>>      nbd_export_put(exp);
>>      if (exp->blk) {
>> +        bdrv_drain(blk_bs(exp->blk));
>>          blk_remove_aio_context_notifier(exp->blk, blk_aio_attached,
>>                                          blk_aio_detach, exp);
>>          blk_unref(exp->blk);
> 
> I think a better fix is to move the whole "if" to nbd_export_put.  In
> fact, nbd_export_close is wrong because exp can be freed by
> nbd_export_close's call to nbd_export_put.

OK, I will fix it in the next version.

Thanks
Wen Congyang


> 
>> @@ -1305,6 +1306,14 @@ static void nbd_trip(void *opaque)
>>          goto invalid_request;
>>      }
>>  
>> +    if (client->closing) {
>> +        /*
>> +         * The client may be closed when we are blocked in
>> +         * nbd_co_receive_request()
>> +         */
>> +        goto done;
>> +    }
> 
> This is okay.
> 
> Paolo
> 
>>      switch (command) {
>>      case NBD_CMD_READ:
>>          TRACE("Request type is READ");
>>
> .
> 




reply via email to

[Prev in Thread] Current Thread [Next in Thread]