NFS: Move details of nfs4_get_sb() to a helper

Clean up: Refactor nfs4_get_sb() to allow its guts to be invoked by
nfs_get_sb().

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index 599e8c5..c105e12 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -274,6 +274,8 @@
 #ifdef CONFIG_NFS_V4
 static int nfs4_validate_text_mount_data(void *options,
 	struct nfs_parsed_mount_data *args, const char *dev_name);
+static int nfs4_try_mount(int flags, const char *dev_name,
+	struct nfs_parsed_mount_data *data, struct vfsmount *mnt);
 static int nfs4_get_sb(struct file_system_type *fs_type,
 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
 static int nfs4_remote_get_sb(struct file_system_type *fs_type,
@@ -2565,25 +2567,15 @@
 	return ret;
 }
 
-/*
- * Get the superblock for an NFS4 mountpoint
- */
-static int nfs4_get_sb(struct file_system_type *fs_type,
-	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
+static int nfs4_try_mount(int flags, const char *dev_name,
+			 struct nfs_parsed_mount_data *data,
+			 struct vfsmount *mnt)
 {
-	struct nfs_parsed_mount_data *data;
 	char *export_path;
 	struct vfsmount *root_mnt;
-	int error = -ENOMEM;
+	int error;
 
-	data = kzalloc(sizeof(*data), GFP_KERNEL);
-	if (data == NULL)
-		goto out_free_data;
-
-	/* Validate the mount data */
-	error = nfs4_validate_mount_data(raw_data, data, dev_name);
-	if (error < 0)
-		goto out;
+	dfprintk(MOUNT, "--> nfs4_try_mount()\n");
 
 	export_path = data->nfs_server.export_path;
 	data->nfs_server.export_path = "/";
@@ -2598,6 +2590,32 @@
 	error = nfs_follow_remote_path(root_mnt, export_path, mnt);
 
 out:
+	dfprintk(MOUNT, "<-- nfs4_try_mount() = %d%s\n", error,
+			error != 0 ? " [error]" : "");
+	return error;
+}
+
+/*
+ * Get the superblock for an NFS4 mountpoint
+ */
+static int nfs4_get_sb(struct file_system_type *fs_type,
+	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
+{
+	struct nfs_parsed_mount_data *data;
+	int error = -ENOMEM;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (data == NULL)
+		goto out_free_data;
+
+	/* Validate the mount data */
+	error = nfs4_validate_mount_data(raw_data, data, dev_name);
+	if (error < 0)
+		goto out;
+
+	error = nfs4_try_mount(flags, dev_name, data, mnt);
+
+out:
 	kfree(data->client_address);
 	kfree(data->nfs_server.export_path);
 	kfree(data->nfs_server.hostname);