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         if (!path)
  34                 return -ENOMEM;
  35
  36         search_key.objectid = BTRFS_LAST_FREE_OBJECTID;
  37         search_key.type = -1;
  38         search_key.offset = (u64)-1;
  39         ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
  40         if (ret < 0)
  41                 goto error;
  42         BUG_ON(ret == 0);
  43         if (path->slots[0] > 0) {
  44                 slot = path->slots[0] - 1;
  45                 l = path->nodes[0];
  46                 btrfs_item_key_to_cpu(l, &found_key, slot);
  47                 *objectid = max_t(u64, found_key.objectid,
  48                                   BTRFS_FIRST_FREE_OBJECTID - 1);
  49         } else {
  50                 *objectid = BTRFS_FIRST_FREE_OBJECTID - 1;
  51         }
  52         ret = 0;
  53 error:
  54         btrfs_free_path(path);
  55         return ret;
  56 }
  57
  58 int btrfs_find_free_objectid(struct btrfs_trans_handle *trans,
  59                              struct btrfs_root *root,
  60                              u64 dirid, u64 *objectid)
  61 {
  62         int ret;
  63         mutex_lock(&root->objectid_mutex);
  64
  65         if (unlikely(root->highest_objectid < BTRFS_FIRST_FREE_OBJECTID)) {
  66                 ret = btrfs_find_highest_inode(root, &root->highest_objectid);
  67                 if (ret)
  68                         goto out;
  69         }
  70
  71         if (unlikely(root->highest_objectid >= BTRFS_LAST_FREE_OBJECTID)) {
  72                 ret = -ENOSPC;
  73                 goto out;
  74         }
  75
  76         *objectid = ++root->highest_objectid;
  77         ret = 0;
  78 out:
  79         mutex_unlock(&root->objectid_mutex);
  80         return ret;
  81 }