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inode-item.c

/*
 * 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"

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;
}

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)
{
      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;

      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 (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);
      BUG_ON(ret);
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;

      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);
            BUG_ON(ret);
            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) {
            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));
      if (ret == 0 && objectid > root->highest_inode)
            root->highest_inode = objectid;
      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;
}

int btrfs_insert_inode(struct btrfs_trans_handle *trans, struct btrfs_root
                   *root, u64 objectid, struct btrfs_inode_item
                   *inode_item)
{
      int ret;
      struct btrfs_key key;

      key.objectid = objectid;
      key.type = BTRFS_INODE_ITEM_KEY;
      key.offset = 0;

      ret = btrfs_insert_item(trans, root, &key, inode_item,
                        sizeof(*inode_item));
      return ret;
}

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