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 = found_key.objectid;
  47         } else {
  48                 *objectid = BTRFS_FIRST_FREE_OBJECTID;
  49         }
  50         ret = 0;
  51 error:
  52         btrfs_free_path(path);
  53         return ret;
  54 }
  55
  56 /*
  57  * walks the btree of allocated inodes and find a hole.
  58  */
  59 int btrfs_find_free_objectid(struct btrfs_trans_handle *trans,
  60                              struct btrfs_root *root,
  61                              u64 dirid, u64 *objectid)
  62 {
  63         struct btrfs_path *path;
  64         struct btrfs_key key;
  65         int ret;
  66         int slot = 0;
  67         u64 last_ino = 0;
  68         int start_found;
  69         struct extent_buffer *l;
  70         struct btrfs_key search_key;
  71         u64 search_start = dirid;
  72
  73         mutex_lock(&root->objectid_mutex);
  74         if (root->last_inode_alloc >= BTRFS_FIRST_FREE_OBJECTID &&
  75             root->last_inode_alloc < BTRFS_LAST_FREE_OBJECTID) {
  76                 *objectid = ++root->last_inode_alloc;
  77                 mutex_unlock(&root->objectid_mutex);
  78                 return 0;
  79         }
  80         path = btrfs_alloc_path();
  81         BUG_ON(!path);
  82         search_start = max(search_start, (u64)BTRFS_FIRST_FREE_OBJECTID);
  83         search_key.objectid = search_start;
  84         search_key.type = 0;
  85         search_key.offset = 0;
  86
  87         start_found = 0;
  88         ret = btrfs_search_slot(trans, root, &search_key, path, 0, 0);
  89         if (ret < 0)
  90                 goto error;
  91
  92         while (1) {
  93                 l = path->nodes[0];
  94                 slot = path->slots[0];
  95                 if (slot >= btrfs_header_nritems(l)) {
  96                         ret = btrfs_next_leaf(root, path);
  97                         if (ret == 0)
  98                                 continue;
  99                         if (ret < 0)
 100                                 goto error;
 101                         if (!start_found) {
 102                                 *objectid = search_start;
 103                                 start_found = 1;
 104                                 goto found;
 105                         }
 106                         *objectid = last_ino > search_start ?
 107                                 last_ino : search_start;
 108                         goto found;
 109                 }
 110                 btrfs_item_key_to_cpu(l, &key, slot);
 111                 if (key.objectid >= search_start) {
 112                         if (start_found) {
 113                                 if (last_ino < search_start)
 114                                         last_ino = search_start;
 115                                 if (key.objectid > last_ino) {
 116                                         *objectid = last_ino;
 117                                         goto found;
 118                                 }
 119                         } else if (key.objectid > search_start) {
 120                                 *objectid = search_start;
 121                                 goto found;
 122                         }
 123                 }
 124                 if (key.objectid >= BTRFS_LAST_FREE_OBJECTID)
 125                         break;
 126
 127                 start_found = 1;
 128                 last_ino = key.objectid + 1;
 129                 path->slots[0]++;
 130         }
 131         BUG_ON(1);
 132 found:
 133         btrfs_release_path(root, path);
 134         btrfs_free_path(path);
 135         BUG_ON(*objectid < search_start);
 136         mutex_unlock(&root->objectid_mutex);
 137         return 0;
 138 error:
 139         btrfs_release_path(root, path);
 140         btrfs_free_path(path);
 141         mutex_unlock(&root->objectid_mutex);
 142         return ret;
 143 }