[Lustre-discuss] Lustre, NFS and mds_getattr_lock operation

[Frederik Ferner]

Andreas,

thanks for your reply.

Andreas Dilger wrote:
> On 2010-05-06, at 11:57, Frederik Ferner wrote:
>> On our Lustre system we are seeing the following error fairly
>> regularly, so far we have not had complaints from users and have
>> not noticed any negative effects, but it would still be nice to
>> understand the errors better. The systems reporting these errors
>> are NFS exporters for subtrees of the Lustre file system.
>> 
>> One the Lustre client/NFS server:
>> 
>> May  6 14:23:09 i16-storage1 kernel: LustreError: 11-0: an error 
>> occurred while communicating with 172.23.68.8 at tcp. The
>> mds_getattr_lock operation failed with -13
> 
> -13 is -EACCESS (per /usr/include/asm-generic/errno-base.h) or
> equivalent
> 
> That just means that someone tried to access a file they don't have
> permission to access.  As to why this is being printed on the console
> is a bit of a mystery, since I haven't seen anything similar.  I
> wonder if NFS is going down some obscure code path that is returning
> the error to the RPC handler instead of stashing this "normal" error
> code inside the reply.

It does not happen every time someone tries to access a directory/file 
they don't have access, i.e. a simple attempt to change into a directory 
where you don't have enough permissions does not trigger the log entry. 
I still suspect some of our users/applications is doing something 
strange but I'm happy to ignore these errors unless some user complains 
and we can reproduce it.

> In any case it is harmless and expected (sigh).  I'd hope it would
> have been removed in newer versions, but I don't know at all.
> 
>> Does anyone know if we should worry about those messages or if we
>> can safely ignore them? Or should we assume that some of our users
>> might have a problem accessing data that they have just not
>> reported? Even though I find that unlikely.

Thanks,

Frederik

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Frederik Ferner
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