NFS: fix an incorrect limit in filelayout_decode_layout()

stable inclusion
from linux-4.19.193
commit 945ebef997227ca8c20bad7f8a8358c8ee57a84a

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

commit 769b01ea68b6c49dc3cde6adf7e53927dacbd3a8 upstream.

The "sizeof(struct nfs_fh)" is two bytes too large and could lead to
memory corruption.  It should be NFS_MAXFHSIZE because that's the size
of the ->data[] buffer.

I reversed the size of the arguments to put the variable on the left.

Fixes: 16b374ca ("NFSv4.1: pnfs: filelayout: add driver's LAYOUTGET and GETDEVICEINFO infrastructure")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>

fs/nfs/filelayout/filelayout.c

@@ -717,7 +717,7 @@ filelayout_decode_layout(struct pnfs_layout_hdr *flo,
 		if (unlikely(!p))
 			goto out_err;
 		fl->fh_array[i]->size = be32_to_cpup(p++);
-		if (sizeof(struct nfs_fh) < fl->fh_array[i]->size) {
+		if (fl->fh_array[i]->size > NFS_MAXFHSIZE) {
 			printk(KERN_ERR "NFS: Too big fh %d received %d\n",
 			       i, fl->fh_array[i]->size);
 			goto out_err;