Re: [PATCH] NFS: Map minor mismatch error to protocol not support error.

[Steve Dickson <SteveD@redhat.com>]

On 06/06/2012 02:31 PM, Chuck Lever wrote:
> 
> On Jun 6, 2012, at 2:12 PM, Steve Dickson wrote:
> 
>> Sservers that only have NFSv4.1 support the
>> NFS4ERR_MINOR_VERS_MISMATCH error is return on
>> v4.0 mounts. Mapping that error to EPROTONOSUPPORT
>> will cause the mount to back off to v3 instead of
>> failing.
> 
> Should we try NFSv4.0 first?
We do try v4.0 first and that mount fails with 
NFS4ERR_MINOR_VERS_MISMATCH. Today the kenrel sends up
an  EIO error which causes the mount to fail. With this 
patch, the kernel will send up a EPROTONOSUPPORT error
which will cause a v3 mount to be tried... 

steved.

> 
>>
>> Signed-off-by: Steve Dickson <steved@redhat.com>
>> ---
>> fs/nfs/nfs4proc.c |    2 ++
>> 1 files changed, 2 insertions(+), 0 deletions(-)
>>
>> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
>> index d48dbef..eda028b 100644
>> --- a/fs/nfs/nfs4proc.c
>> +++ b/fs/nfs/nfs4proc.c
>> @@ -105,6 +105,8 @@ static int nfs4_map_errors(int err)
>> 		return -EINVAL;
>> 	case -NFS4ERR_SHARE_DENIED:
>> 		return -EACCES;
>> +	case -NFS4ERR_MINOR_VERS_MISMATCH:
>> +		return -EPROTONOSUPPORT;
>> 	default:
>> 		dprintk("%s could not handle NFSv4 error %d\n",
>> 				__func__, -err);
>> -- 
>> 1.7.1
>>
>> --
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> 
> ---
> Chuck Lever
> chuck [dot] lever [at] oracle [dot] com
> 
> 
> 
>