fs: btrfs: Crossport rbtree-utils from btrfs-progs

This is needed for incoming extent-cache infrastructure.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Marek Behún <marek.behun@nic.cz>

fs/btrfs/Makefile

@@ -3,4 +3,5 @@
 # 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
 
 obj-y := btrfs.o chunk-map.o compression.o ctree.o dev.o dir-item.o \
-	extent-io.o inode.o root.o subvolume.o crypto/hash.o disk-io.o
+	extent-io.o inode.o root.o subvolume.o crypto/hash.o disk-io.o \
+	common/rbtree-utils.o extent-cache.o

fs/btrfs/common/rbtree-utils.c

@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) 2014 Facebook.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <linux/errno.h>
+#include "rbtree-utils.h"
+
+int rb_insert(struct rb_root *root, struct rb_node *node,
+	      rb_compare_nodes comp)
+{
+	struct rb_node **p = &root->rb_node;
+	struct rb_node *parent = NULL;
+	int ret;
+
+	while(*p) {
+		parent = *p;
+
+		ret = comp(parent, node);
+		if (ret < 0)
+			p = &(*p)->rb_left;
+		else if (ret > 0)
+			p = &(*p)->rb_right;
+		else
+			return -EEXIST;
+	}
+
+	rb_link_node(node, parent, p);
+	rb_insert_color(node, root);
+	return 0;
+}
+
+struct rb_node *rb_search(struct rb_root *root, void *key, rb_compare_keys comp,
+			  struct rb_node **next_ret)
+{
+	struct rb_node *n = root->rb_node;
+	struct rb_node *parent = NULL;
+	int ret = 0;
+
+	while(n) {
+		parent = n;
+
+		ret = comp(n, key);
+		if (ret < 0)
+			n = n->rb_left;
+		else if (ret > 0)
+			n = n->rb_right;
+		else
+			return n;
+	}
+
+	if (!next_ret)
+		return NULL;
+
+	if (parent && ret > 0)
+		parent = rb_next(parent);
+
+	*next_ret = parent;
+	return NULL;
+}
+
+void rb_free_nodes(struct rb_root *root, rb_free_node free_node)
+{
+	struct rb_node *node;
+
+	while ((node = rb_first(root))) {
+		rb_erase(node, root);
+		free_node(node);
+	}
+}

fs/btrfs/common/rbtree-utils.h

@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2014 Facebook.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#ifndef __RBTREE_UTILS__
+#define __RBTREE_UTILS__
+
+#include <linux/rbtree.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* The common insert/search/free functions */
+typedef int (*rb_compare_nodes)(struct rb_node *node1, struct rb_node *node2);
+typedef int (*rb_compare_keys)(struct rb_node *node, void *key);
+typedef void (*rb_free_node)(struct rb_node *node);
+
+int rb_insert(struct rb_root *root, struct rb_node *node,
+	      rb_compare_nodes comp);
+/*
+ * In some cases, we need return the next node if we don't find the node we
+ * specify. At this time, we can use next_ret.
+ */
+struct rb_node *rb_search(struct rb_root *root, void *key, rb_compare_keys comp,
+			  struct rb_node **next_ret);
+void rb_free_nodes(struct rb_root *root, rb_free_node free_node);
+
+#define FREE_RB_BASED_TREE(name, free_func)		\
+static void free_##name##_tree(struct rb_root *root)	\
+{							\
+	rb_free_nodes(root, free_func);			\
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif