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 #include "internal.h"
  23
  24 /*
  25  * walks the btree of allocated inodes and find a hole.
  26  */
  27 int btrfs_find_free_objectid(struct btrfs_trans_handle *trans,
  28                              struct btrfs_root *root,
  29                              u64 dirid, u64 *objectid)
  30 {
  31         struct btrfs_path *path;
  32         struct btrfs_key key;
  33         int ret;
  34         int slot = 0;
  35         u64 last_ino = 0;
  36         int start_found;
  37         struct extent_buffer *l;
  38         struct btrfs_key search_key;
  39         u64 search_start = dirid;
  40
  41         path = btrfs_alloc_path();
  42         BUG_ON(!path);
  43         search_start = root->last_inode_alloc;
  44         search_start = max((unsigned long long)search_start,
  45                                 BTRFS_FIRST_FREE_OBJECTID);
  46         search_key.objectid = search_start;
  47         search_key.offset = 0;
  48         search_key.type = 0;
  49
  50         btrfs_init_path(path);
  51         start_found = 0;
  52         ret = btrfs_search_slot(trans, root, &search_key, path, 0, 0);
  53         if (ret < 0)
  54                 goto error;
  55
  56         if (path->slots[0] > 0)
  57                 path->slots[0]--;
  58
  59         while (1) {
  60                 l = path->nodes[0];
  61                 slot = path->slots[0];
  62                 if (slot >= btrfs_header_nritems(l)) {
  63                         ret = btrfs_next_leaf(root, path);
  64                         if (ret == 0)
  65                                 continue;
  66                         if (ret < 0)
  67                                 goto error;
  68                         if (!start_found) {
  69                                 *objectid = search_start;
  70                                 start_found = 1;
  71                                 goto found;
  72                         }
  73                         *objectid = last_ino > search_start ?
  74                                 last_ino : search_start;
  75                         goto found;
  76                 }
  77                 btrfs_item_key_to_cpu(l, &key, slot);
  78                 if (key.objectid >= search_start) {
  79                         if (start_found) {
  80                                 if (last_ino < search_start)
  81                                         last_ino = search_start;
  82                                 if (key.objectid > last_ino) {
  83                                         *objectid = last_ino;
  84                                         goto found;
  85                                 }
  86                         }
  87                 }
  88                 start_found = 1;
  89                 last_ino = key.objectid + 1;
  90                 path->slots[0]++;
  91         }
  92         // FIXME -ENOSPC
  93 found:
  94         root->last_inode_alloc = *objectid;
  95         btrfs_free_path(path);
  96         BUG_ON(*objectid < search_start);
  97         return 0;
  98 error:
  99         btrfs_free_path(path);
 100         return ret;
 101 }