/*
   * Copyright (C) 2007 Oracle.  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 "ctree.h"
  #include "disk-io.h"

  #include "transaction.h"

  static int find_name_in_backref(struct btrfs_path *path, const char *name,

  			 int name_len, struct btrfs_inode_ref **ref_ret)
  {
  	struct extent_buffer *leaf;
  	struct btrfs_inode_ref *ref;
  	unsigned long ptr;
  	unsigned long name_ptr;
  	u32 item_size;
  	u32 cur_offset = 0;
  	int len;
  
  	leaf = path->nodes[0];
  	item_size = btrfs_item_size_nr(leaf, path->slots[0]);
  	ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
  	while (cur_offset < item_size) {
  		ref = (struct btrfs_inode_ref *)(ptr + cur_offset);
  		len = btrfs_inode_ref_name_len(leaf, ref);
  		name_ptr = (unsigned long)(ref + 1);
  		cur_offset += len + sizeof(*ref);
  		if (len != name_len)
  			continue;
  		if (memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0) {
  			*ref_ret = ref;
  			return 1;
  		}
  	}
  	return 0;
  }

  struct btrfs_inode_ref *
  btrfs_lookup_inode_ref(struct btrfs_trans_handle *trans,
  			struct btrfs_root *root,
  			struct btrfs_path *path,
  			const char *name, int name_len,
  			u64 inode_objectid, u64 ref_objectid, int mod)
  {
  	struct btrfs_key key;
  	struct btrfs_inode_ref *ref;
  	int ins_len = mod < 0 ? -1 : 0;
  	int cow = mod != 0;
  	int ret;
  
  	key.objectid = inode_objectid;
  	key.type = BTRFS_INODE_REF_KEY;
  	key.offset = ref_objectid;
  
  	ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
  	if (ret < 0)
  		return ERR_PTR(ret);
  	if (ret > 0)
  		return NULL;
  	if (!find_name_in_backref(path, name, name_len, &ref))
  		return NULL;
  	return ref;
  }

  int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
  			   struct btrfs_root *root,
  			   const char *name, int name_len,

  			   u64 inode_objectid, u64 ref_objectid, u64 *index)

  {
  	struct btrfs_path *path;
  	struct btrfs_key key;
  	struct btrfs_inode_ref *ref;
  	struct extent_buffer *leaf;
  	unsigned long ptr;
  	unsigned long item_start;
  	u32 item_size;
  	u32 sub_item_len;
  	int ret;
  	int del_len = name_len + sizeof(*ref);
  
  	key.objectid = inode_objectid;
  	key.offset = ref_objectid;
  	btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
  
  	path = btrfs_alloc_path();
  	if (!path)
  		return -ENOMEM;

  	path->leave_spinning = 1;

  	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
  	if (ret > 0) {
  		ret = -ENOENT;
  		goto out;
  	} else if (ret < 0) {
  		goto out;
  	}
  	if (!find_name_in_backref(path, name, name_len, &ref)) {
  		ret = -ENOENT;
  		goto out;
  	}
  	leaf = path->nodes[0];
  	item_size = btrfs_item_size_nr(leaf, path->slots[0]);

  
  	if (index)
  		*index = btrfs_inode_ref_index(leaf, ref);

  	if (del_len == item_size) {
  		ret = btrfs_del_item(trans, root, path);
  		goto out;
  	}
  	ptr = (unsigned long)ref;
  	sub_item_len = name_len + sizeof(*ref);
  	item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
  	memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
  			      item_size - (ptr + sub_item_len - item_start));
  	ret = btrfs_truncate_item(trans, root, path,
  				  item_size - sub_item_len, 1);

  out:
  	btrfs_free_path(path);
  	return ret;
  }
  
  int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
  			   struct btrfs_root *root,
  			   const char *name, int name_len,

  			   u64 inode_objectid, u64 ref_objectid, u64 index)

  {
  	struct btrfs_path *path;
  	struct btrfs_key key;
  	struct btrfs_inode_ref *ref;
  	unsigned long ptr;
  	int ret;
  	int ins_len = name_len + sizeof(*ref);
  
  	key.objectid = inode_objectid;
  	key.offset = ref_objectid;
  	btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
  
  	path = btrfs_alloc_path();
  	if (!path)
  		return -ENOMEM;

  	path->leave_spinning = 1;

  	ret = btrfs_insert_empty_item(trans, root, path, &key,
  				      ins_len);
  	if (ret == -EEXIST) {
  		u32 old_size;
  
  		if (find_name_in_backref(path, name, name_len, &ref))
  			goto out;
  
  		old_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
  		ret = btrfs_extend_item(trans, root, path, ins_len);

  		ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
  				     struct btrfs_inode_ref);
  		ref = (struct btrfs_inode_ref *)((unsigned long)ref + old_size);
  		btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);

  		btrfs_set_inode_ref_index(path->nodes[0], ref, index);

  		ptr = (unsigned long)(ref + 1);
  		ret = 0;
  	} else if (ret < 0) {

  		if (ret == -EOVERFLOW)
  			ret = -EMLINK;

  		goto out;
  	} else {
  		ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
  				     struct btrfs_inode_ref);
  		btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);

  		btrfs_set_inode_ref_index(path->nodes[0], ref, index);

  		ptr = (unsigned long)(ref + 1);
  	}
  	write_extent_buffer(path->nodes[0], name, ptr, name_len);
  	btrfs_mark_buffer_dirty(path->nodes[0]);
  
  out:
  	btrfs_free_path(path);
  	return ret;
  }

  int btrfs_insert_empty_inode(struct btrfs_trans_handle *trans,
  			     struct btrfs_root *root,
  			     struct btrfs_path *path, u64 objectid)

  {

  	struct btrfs_key key;
  	int ret;
  	key.objectid = objectid;

  	btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
  	key.offset = 0;

  	ret = btrfs_insert_empty_item(trans, root, path, &key,
  				      sizeof(struct btrfs_inode_item));

  	return ret;
  }

  int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root

  		       *root, struct btrfs_path *path,
  		       struct btrfs_key *location, int mod)

  {

  	int ins_len = mod < 0 ? -1 : 0;
  	int cow = mod != 0;

  	int ret;
  	int slot;

  	struct extent_buffer *leaf;

  	struct btrfs_key found_key;

  	ret = btrfs_search_slot(trans, root, location, path, ins_len, cow);
  	if (ret > 0 && btrfs_key_type(location) == BTRFS_ROOT_ITEM_KEY &&
  	    location->offset == (u64)-1 && path->slots[0] != 0) {
  		slot = path->slots[0] - 1;

  		leaf = path->nodes[0];
  		btrfs_item_key_to_cpu(leaf, &found_key, slot);

  		if (found_key.objectid == location->objectid &&
  		    btrfs_key_type(&found_key) == btrfs_key_type(location)) {
  			path->slots[0]--;
  			return 0;
  		}
  	}
  	return ret;

  }