nfsd4_path() allocates a temporary filehandle and then fails to free it
before the function exits, leaking reference counts to the dentry and
export that it refers to.

Also, nfsd4_lookupp() puts the result of exp_pseudoroot() in a temporary
filehandle which it releases on success of exp_pseudoroot() but not on
failure; fix exp_pseudoroot to ensure that on failure it releases the
filehandle before returning.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>