Re: Random IO errors on nfs clients running linux > 4.20

[Chuck Lever <chuck.lever@oracle.com>]

> On Oct 26, 2020, at 9:42 AM, Alberto Gonzalez Iniesta <alberto.gonzalez@udima.es> wrote:
> 
> On Wed, Sep 09, 2020 at 09:47:27AM -0400, J. Bruce Fields wrote:
>> On Wed, Sep 09, 2020 at 11:29:00AM +0200, Alberto Gonzalez Iniesta wrote:
>>> On Thu, Apr 30, 2020 at 01:32:00PM -0400, J. Bruce Fields wrote:
>>>> On Wed, Apr 29, 2020 at 07:15:27PM +0200, Alberto Gonzalez Iniesta wrote:
>>>>> We can run the previous "ls -lR" 20 times and get no error, or get
>>>>> this "ls: leyendo el directorio 'Becas y ayudas/': Error de entrada/salida"
>>>>> (ls: reading directorio 'Becas y ayudas/': Input/Output Error") every
>>>>> now and then.
>>>>> 
>>>>> The error happens (obviously?) with ls, rsync and the users's GUI tools.
>>>>> 
>>>>> There's nothing in dmesg (or elsewhere).
>>>>> These are the kernels with tried:
>>>>> 4.18.0-25   -> Can't reproduce
>>>>> 4.19.0      -> Can't reproduce
>>>>> 4.20.17     -> Happening (hard to reproduce)
>>>>> 5.0.0-15    -> Happening (hard to reproduce)
>>>>> 5.3.0-45    -> Happening (more frequently)
>>>>> 5.6.0-rc7   -> Reproduced a couple of times after boot, then nothing
>>>>> 
>>>>> We did long (as in daylong) testing trying to reproduce this with all
>>>>> those kernel versions, so we are pretty sure 4.18 and 4.19 don't
>>>>> experience this and our Ubuntu 16.04 clients don't have any issue.
>>>>> 
>>>>> I know we aren't providing much info but we are really looking forward
>>>>> to doing all the testing required (we already spent lots of time in it).
>>>>> 
>>>>> Thanks for your work.
>> 
>> So all I notice from this one is the readdir EIO came from call_decode.
>> I suspect that means it failed in the xdr decoding.  Looks like xdr
>> decoding of the actual directory data (which is the complicated part) is
>> done later, so this means it failed decoding the header or verifier,
>> which is a little odd:
>> 
>>> Sep  8 16:03:23 portatil264 kernel: [15033.016276] RPC:  3284 call_decode result -5
>>> Sep  8 16:03:23 portatil264 kernel: [15033.016281] nfs41_sequence_process: Error 1 free the slot 
>>> Sep  8 16:03:23 portatil264 kernel: [15033.016286] RPC:       wake_up_first(00000000d3f50f4d "ForeChannel Slot table")
>>> Sep  8 16:03:23 portatil264 kernel: [15033.016288] nfs4_free_slot: slotid 0 highest_used_slotid 4294967295
>>> Sep  8 16:03:23 portatil264 kernel: [15033.016290] RPC:  3284 return 0, status -5
>>> Sep  8 16:03:23 portatil264 kernel: [15033.016291] RPC:  3284 release task
>>> Sep  8 16:03:23 portatil264 kernel: [15033.016295] RPC:       freeing buffer of size 4144 at 00000000a3649daf
>>> Sep  8 16:03:23 portatil264 kernel: [15033.016298] RPC:  3284 release request 0000000079df89b2
>>> Sep  8 16:03:23 portatil264 kernel: [15033.016300] RPC:       wake_up_first(00000000c5ee49ee "xprt_backlog")
>>> Sep  8 16:03:23 portatil264 kernel: [15033.016302] RPC:       rpc_release_client(00000000b930c343)
>>> Sep  8 16:03:23 portatil264 kernel: [15033.016304] RPC:  3284 freeing task
>>> Sep  8 16:03:23 portatil264 kernel: [15033.016309] _nfs4_proc_readdir: returns -5
>>> Sep  8 16:03:23 portatil264 kernel: [15033.016318] NFS: readdir(departamentos/innovacion) returns -5
> 
> Hi, Bruce et al.
> 
> Is there anything we can do to help debugging/fixing this? It's still
> biting our users with a +4.20.x kernel.

Alberto, can you share a snippet of a raw network capture that shows
the READDIR Reply that fails to decode?


--
Chuck Lever