LXR linux/fs/btrfs/inode-map.c

   1/*
   2 * Copyright (C) 2007 Oracle.  All rights reserved.
   3 *
   4 * This program is free software; you can redistribute it and/or
   5 * modify it under the terms of the GNU General Public
   6 * License v2 as published by the Free Software Foundation.
   7 *
   8 * This program is distributed in the hope that it will be useful,
   9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11 * General Public License for more details.
  12 *
  13 * You should have received a copy of the GNU General Public
  14 * License along with this program; if not, write to the
  15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16 * Boston, MA 021110-1307, USA.
  17 */
  18
  19#include "ctree.h"
  20#include "disk-io.h"
  21#include "transaction.h"
  22
  23int btrfs_find_highest_inode(struct btrfs_root *root, u64 *objectid)
  24{
  25        struct btrfs_path *path;
  26        int ret;
  27        struct extent_buffer *l;
  28        struct btrfs_key search_key;
  29        struct btrfs_key found_key;
  30        int slot;
  31
  32        path = btrfs_alloc_path();
  33        BUG_ON(!path);
  34
  35        search_key.objectid = BTRFS_LAST_FREE_OBJECTID;
  36        search_key.type = -1;
  37        search_key.offset = (u64)-1;
  38        ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
  39        if (ret < 0)
  40                goto error;
  41        BUG_ON(ret == 0);
  42        if (path->slots[0] > 0) {
  43                slot = path->slots[0] - 1;
  44                l = path->nodes[0];
  45                btrfs_item_key_to_cpu(l, &found_key, slot);
  46                *objectid = max_t(u64, found_key.objectid,
  47                                  BTRFS_FIRST_FREE_OBJECTID - 1);
  48        } else {
  49                *objectid = BTRFS_FIRST_FREE_OBJECTID - 1;
  50        }
  51        ret = 0;
  52error:
  53        btrfs_free_path(path);
  54        return ret;
  55}
  56
  57int btrfs_find_free_objectid(struct btrfs_trans_handle *trans,
  58                             struct btrfs_root *root,
  59                             u64 dirid, u64 *objectid)
  60{
  61        int ret;
  62        mutex_lock(&root->objectid_mutex);
  63
  64        if (unlikely(root->highest_objectid < BTRFS_FIRST_FREE_OBJECTID)) {
  65                ret = btrfs_find_highest_inode(root, &root->highest_objectid);
  66                if (ret)
  67                        goto out;
  68        }
  69
  70        if (unlikely(root->highest_objectid >= BTRFS_LAST_FREE_OBJECTID)) {
  71                ret = -ENOSPC;
  72                goto out;
  73        }
  74
  75        *objectid = ++root->highest_objectid;
  76        ret = 0;
  77out:
  78        mutex_unlock(&root->objectid_mutex);
  79        return ret;
  80}
  81