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
  23 int 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;
  52 error:
  53         btrfs_free_path(path);
  54         return ret;
  55 }
  56
  57 int 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;
  77 out:
  78         mutex_unlock(&root->objectid_mutex);
  79         return ret;
  80 }