NFSD: detect mismatch of file handle and delegation stateid in OPEN op

NFSD: detect mismatch of file handle and delegation stateid in OPEN op

When the client sends an OPEN with claim type CLAIM_DELEG_CUR_FH or
CLAIM_DELEGATION_CUR, the delegation stateid and the file handle
must belong to the same file, otherwise return NFS4ERR_INVAL.

Note that RFC8881, section 8.2.4, mandates the server to return
NFS4ERR_BAD_STATEID if the selected table entry does not match the
current filehandle. However returning NFS4ERR_BAD_STATEID in the
OPEN causes the client to retry the operation and therefor get the
client into a loop. To avoid this situation we return NFS4ERR_INVAL
instead.

Reported-by: Petro Pavlov <petro.pavlov@vastdata.com>
Fixes: c44c5eeb2c02 ("[PATCH] nfsd4: add open state code for CLAIM_DELEGATE_CUR")
Cc: stable@vger.kernel.org
Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>