Apple has a bug in credit handling with their smbfs, it seems :-)

[Stefan Metzmacher]

Am 23.01.19 um 20:44 schrieb Jeremy Allison via samba-technical:
> On Mon, Jan 21, 2019 at 07:22:48PM -0800, Richard Sharpe via samba-technical wrote:
>> Hi folks,
>>
>> Apple has a bug in their handling of credits when Samba returns
>> STATUS_PENDING for a SESSION SETUP request.
>>
>> Such responses only seem to occur when the Samba server is under heavy load.
>>
>> Samba issues one credit in such cases, and, as per the spec issues
>> zero credits in the final successful response to the SESSION SETUP.
>>
>> The Mac then issues a TREE CREATE, consuming one credit and getting one credit.
>>
>> The Mac then issues a compound CREATE and CLOSE. This is a protocol
>> violation and Samba drops the connection.
>>
>> I have communicated this issue to Apple, but I also created the
>> attached patch to mitigate the issue while Apple thinks about fixing
>> their code.
>>
>> Is it worth doing this? Is it going to work?
> 
> So this is sending credits on the SESSION SETUP
> interim reply, and then also on the final SESSION SETUP
> reply, yeah ?
> 
> Have you tested this against the Apple client ?
> 
> It's really ugly and a protocol violation :-).
> 
> How often does this problem occur ? If it did
> go in it'd have to be configured off by default
> but I'm not convinced yet :-).

I'd propose to skip the STATUS_PENDING using
smb2_request_set_async_internal() and leave the credit handling as is.

metze


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