NFS/pNFS: Fix a leak of the layout 'plh_outstanding' counter

stable inclusion
from linux-4.19.169
commit b2f9fbbc3fa20f066e20f1d676175e4af0e177ba

--------------------------------

commit cb2856c5 upstream.

If we exit _lgopen_prepare_attached() without setting a layout, we will
currently leak the plh_outstanding counter.

Fixes: 411ae722 ("pNFS: Wait for stale layoutget calls to complete in pnfs_update_layout()")
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: NCheng Jian <cj.chengjian@huawei.com>

fs/nfs/pnfs.c

@@ -2138,6 +2138,7 @@ static void _lgopen_prepare_attached(struct nfs4_opendata *data,
 					     &rng, GFP_KERNEL);
 	if (!lgp) {
 		pnfs_clear_first_layoutget(lo);
+		nfs_layoutget_end(lo);
 		pnfs_put_layout_hdr(lo);
 		return;
 	}