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