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 <stdio.h>
  20 #include <stdlib.h>
  21 #include "kerncompat.h"
  22 #include "radix-tree.h"
  23 #include "ctree.h"
  24 #include "disk-io.h"
  25 #include "transaction.h"
  26
  27 /*
  28  * walks the btree of allocated inodes and find a hole.
  29  */
  30 int btrfs_find_free_objectid(struct btrfs_trans_handle *trans,
  31                              struct btrfs_root *root,
  32                              u64 dirid, u64 *objectid)
  33 {
  34         struct btrfs_path path;
  35         struct btrfs_key key;
  36         int ret;
  37         u64 hole_size = 0;
  38         int slot = 0;
  39         u64 last_ino = 0;
  40         int start_found;
  41         struct btrfs_leaf *l;
  42         struct btrfs_key search_key;
  43         u64 search_start = dirid;
  44
  45         if (root->fs_info->last_inode_alloc_dirid == dirid)
  46                 search_start = root->fs_info->last_inode_alloc;
  47
  48         if (search_start < BTRFS_FIRST_FREE_OBJECTID)
  49                 search_start = BTRFS_FIRST_FREE_OBJECTID;
  50         search_key.objectid = search_start;
  51         search_key.flags = 0;
  52         search_key.offset = 0;
  53
  54         btrfs_init_path(&path);
  55         start_found = 0;
  56         ret = btrfs_search_slot(trans, root, &search_key, &path, 0, 0);
  57         if (ret < 0)
  58                 goto error;
  59
  60         if (path.slots[0] > 0)
  61                 path.slots[0]--;
  62
  63         while (1) {
  64                 l = &path.nodes[0]->leaf;
  65                 slot = path.slots[0];
  66                 if (slot >= btrfs_header_nritems(&l->header)) {
  67                         ret = btrfs_next_leaf(root, &path);
  68                         if (ret == 0)
  69                                 continue;
  70                         if (ret < 0)
  71                                 goto error;
  72                         if (!start_found) {
  73                                 *objectid = search_start;
  74                                 start_found = 1;
  75                                 goto found;
  76                         }
  77                         *objectid = last_ino > search_start ?
  78                                 last_ino : search_start;
  79                         goto found;
  80                 }
  81                 btrfs_disk_key_to_cpu(&key, &l->items[slot].key);
  82                 if (key.objectid >= search_start) {
  83                         if (start_found) {
  84                                 if (last_ino < search_start)
  85                                         last_ino = search_start;
  86                                 hole_size = key.objectid - last_ino;
  87                                 if (hole_size > 0) {
  88                                         *objectid = last_ino;
  89                                         goto found;
  90                                 }
  91                         }
  92                 }
  93                 start_found = 1;
  94                 last_ino = key.objectid + 1;
  95                 path.slots[0]++;
  96         }
  97         // FIXME -ENOSPC
  98 found:
  99         root->fs_info->last_inode_alloc = *objectid;
 100         root->fs_info->last_inode_alloc_dirid = dirid;
 101         btrfs_release_path(root, &path);
 102         BUG_ON(*objectid < search_start);
 103         return 0;
 104 error:
 105         btrfs_release_path(root, &path);
 106         return ret;
 107 }