pNFS: Fix a memory leak when attempted pnfs fails

pNFS: Fix a memory leak when attempted pnfs fails

commit 1ca018d28d96d07788474abf66a5f3e9594841f5 upstream.

pnfs_do_write() expects the call to pnfs_write_through_mds() to free the
pgio header and to release the layout segment before exiting. The problem
is that nfs_pgio_data_destroy() doesn't actually do this; it only frees
the memory allocated by nfs_generic_pgio().

Ditto for pnfs_do_read()...

Fix in both cases is to add a call to hdr->release(hdr).

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>