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