Jens Axboe wrote:
> On Tue, Feb 03 2009, Alan D. Brunelle wrote:
>> According to the recv(2) man page:
>>
>> The return value will be 0 when the peer has performed an orderly
>> shutdown.
>>
>> Yet the code in read_data_net and net_get_header both attempt to re-read
>> from a socket that will _never_ have data. (I hit this problem today on
>> blktrace2 - I've got orderly shut downs in place.)
>>
>> Does this pseudo-patch break something?
>>
>> diff --git a/blktrace.c b/blktrace.c
>> index c55b491..9ef7313 100644
>> --- a/blktrace.c
>> +++ b/blktrace.c
>> @@ -550,7 +550,7 @@ static int read_data_net(struct thread_information
>> *tip, voi
>> ret = recv(nc->in_fd, buf, bytes_left, MSG_WAITALL);
>>
>> if (!ret)
>> - continue;
>> + return 0;
>> else if (ret < 0) {
>> if (errno != EAGAIN) {
>> perror(tip->fn);
>> @@ -1466,8 +1466,7 @@ static int net_get_header(struct net_connection *nc,
>> usleep(1000);
>> continue;
>> } else if (!ret) {
>> - usleep(1000);
>> - continue;
>> + return 0;
>> } else {
>> p += ret;
>> bytes_left -= ret;
>
> My bad, I think the patch looks correct. Feel free to commit it, you can
> add my acked-by to it.
>
OK, but this patch may not be sufficient: need to look at it some more
(in particular, just doing this causes other errors to occur because the
connections still try to be read - typically an infinite hang (reading
0)). In blktrace2 I'm adding in orderly shutdowns on both ends of the
socket.
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