2:46 p.m.
Dan and I chatted more on IRC.
So if there is no need to run FSAL_PROXY with other FSALs, returning ERR_FSAL_NOT_OPENED
should work to eliminate the LogCrit.
However, the NFS v3 CREATE case will still cause increment of open_fd_count, however, no
messages will ensue (the count going above the hi water mark is only logged in a function
never called in the FSAL_PROXY paths). Unfortunately this will eventually result in
Futility count behavior...
A not too ugly hack is for FSAL_PROXY to decrement open_fd_count in the NFS v3 CREATE case
(which will go negative unless there are other non-PROXY opens...) so that it gets
incremented back up by open2_by_name. If other FSALs are in use, there is some possibility
of a race such that fsal_close is called to close the last global fd from another FSAL
between the decrement and increment, thus resulting in a negative count and a LogCrit.
Another option would be for FSAL_PROXY to note that an fsal_obj_handle was created in such
a create case, and the first time fsal_close is called, return ERR_FSAL_NO_ERROR so the
extra open_fd_count is decremented.
Frank
-----Original Message-----
From: Daniel Gryniewicz [mailto:dang@redhat.com]
Sent: Wednesday, May 16, 2018 7:36 AM
To: devel(a)lists.nfs-ganesha.org
Subject: [Nfs-ganesha-devel] Re: FSAL_PROXY : "open_fd_count is negative"
Yeah, this is a problem. Mixing doing it in common code and in the FSALs will
always cause this problem. I'm tempted to say it should always be done in
common code, so it never breaks; but that way we can't have FSALs that don't
actually use real FDs control their contribution.
We're a long way from that working, though.
I don't see a good way to fix this, other than PROXY actually using the proper
infrastructure. The way it is now, you cannot mix PROXY and any other FSAL and
have a working system.
Daniel
On 05/16/2018 10:16 AM, Frank Filz wrote:
>> How about this:
>>
>> pxy_close() just returns ERR_FSAL_NO_ERROR. How about, instead, it
>> returns ERR_FSAL_NOT_OPENED?
>
> Yea, that would do it. I see that fsal_close converts ERR_FSAL_NOT_OPENED
to ERR_FSAL_NO_ERROR.
>
> Though that leaves us with this increment occurring without decrement:
>
> FSAL/fsal_helper.c:413 open2_by_name : (void )
> atomic_inc_size_t(&open_fd_count);
>
>> Daniel
>>
>> On 05/16/2018 09:28 AM, Frank Filz wrote:
>>> This is an example of why we need help from the FSAL in managing
>> open_fd_count.
>>>
>>> The counter is decremented in fsal_close.
>>>
>>> The primary place it is incremented is in fsal_reopen_obj, which
>>> FSAL_PROXY
>> never calls since it has absolutely no need to maintain a global file
>> descriptor (it uses the always available special stateids).
>>>
>>> We could move the decrement into the FSAL itself which would then
>>> know
>> exactly when it has closed a resource it was counting with open_fd_count.
>>>
>>> Frank
>>>
>>>> -----Original Message-----
>>>> From: Daniel Gryniewicz [mailto:dang@redhat.com]
>>>> Sent: Wednesday, May 16, 2018 5:29 AM
>>>> To: devel(a)lists.nfs-ganesha.org
>>>> Subject: [Nfs-ganesha-devel] Re: FSAL_PROXY : "open_fd_count is
negative"
>>>>
>>>> Hi, Patrice,
>>>>
>>>> This is definitely a problem. The LRU uses open_fd_count to
>>>> determine when it needs to run, and when it's having problems. I
>>>> made that change specifically to catch problems where it goes
>>>> negative (which the LRU counts as huge...)
>>>>
>>>> Do you have a reproducer? Preferably a relatively simple one? I'd
>>>> love to get this fixed.
>>>>
>>>> Daniel
>>>>
>>>> On 05/16/2018 04:28 AM, patrice.lucas(a)cea.fr wrote:
>>>>> Since 2.7-dev.8 and the Daniel's patch fc5e13ecb "adding a
message
>>>>> when open_fd_count comes negative", FSAL_PROXY tests logs are
full
>>>>> of these critical messages : "open_fd_count is negative".
>>>>>
>>>>>
>>>>> Should I worry about and try to fix it ? Or is this open_fd_count
>>>>> deprecated and unused ?
>>>>>
>>>>>
>>>>> Best regards,
>>>>>
>>>>> Patrice
>>>>> _______________________________________________
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>>>
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