nfs: pass string length to pr_notice message about readdir loops

There is no guarantee that the strings in the nfs_cache_array will be
NULL-terminated. In the event that we end up hitting a readdir loop, we
need to ensure that we pass the warning message the length of the
string.

Reported-by: Lachlan McIlroy <lmcilroy@redhat.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

fs/nfs/dir.c

@@ -313,10 +313,9 @@ int nfs_readdir_search_for_cookie(struct nfs_cache_array *array, nfs_readdir_des
 					if (printk_ratelimit()) {
 						pr_notice("NFS: directory %pD2 contains a readdir loop."
 								"Please contact your server vendor.  "
-								"The file: %s has duplicate cookie %llu\n",
-								desc->file,
-								array->array[i].string.name,
-								*desc->dir_cookie);
+								"The file: %.*s has duplicate cookie %llu\n",
+								desc->file, array->array[i].string.len,
+								array->array[i].string.name, *desc->dir_cookie);
 					}
 					status = -ELOOP;
 					goto out;