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 <linux/module.h>
  20 #include "ctree.h"
  21 #include "disk-io.h"
  22 #include "transaction.h"
  23
  24 int btrfs_find_highest_inode(struct btrfs_root *root, u64 *objectid)
  25 {
  26         struct btrfs_path *path;
  27         int ret;
  28         struct btrfs_leaf *l;
  29         struct btrfs_key search_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 = btrfs_buffer_leaf(path->nodes[0]);
  44                 *objectid = btrfs_disk_key_objectid(&l->items[slot].key);
  45         } else {
  46                 *objectid = BTRFS_FIRST_FREE_OBJECTID;
  47         }
  48         ret = 0;
  49 error:
  50         btrfs_free_path(path);
  51         return ret;
  52 }
  53
  54 /*
  55  * walks the btree of allocated inodes and find a hole.
  56  */
  57 int btrfs_find_free_objectid(struct btrfs_trans_handle *trans,
  58                              struct btrfs_root *root,
  59                              u64 dirid, u64 *objectid)
  60 {
  61         struct btrfs_path *path;
  62         struct btrfs_key key;
  63         int ret;
  64         u64 hole_size = 0;
  65         int slot = 0;
  66         u64 last_ino = 0;
  67         int start_found;
  68         struct btrfs_leaf *l;
  69         struct btrfs_key search_key;
  70         u64 search_start = dirid;
  71
  72         path = btrfs_alloc_path();
  73         BUG_ON(!path);
  74         search_key.flags = 0;
  75         search_start = root->last_inode_alloc;
  76         search_start = max(search_start, BTRFS_FIRST_FREE_OBJECTID);
  77         search_key.objectid = search_start;
  78         search_key.offset = 0;
  79
  80         btrfs_init_path(path);
  81         start_found = 0;
  82         ret = btrfs_search_slot(trans, root, &search_key, path, 0, 0);
  83         if (ret < 0)
  84                 goto error;
  85
  86         if (path->slots[0] > 0)
  87                 path->slots[0]--;
  88
  89         while (1) {
  90                 l = btrfs_buffer_leaf(path->nodes[0]);
  91                 slot = path->slots[0];
  92                 if (slot >= btrfs_header_nritems(&l->header)) {
  93                         ret = btrfs_next_leaf(root, path);
  94                         if (ret == 0)
  95                                 continue;
  96                         if (ret < 0)
  97                                 goto error;
  98                         if (!start_found) {
  99                                 *objectid = search_start;
 100                                 start_found = 1;
 101                                 goto found;
 102                         }
 103                         *objectid = last_ino > search_start ?
 104                                 last_ino : search_start;
 105                         goto found;
 106                 }
 107                 btrfs_disk_key_to_cpu(&key, &l->items[slot].key);
 108                 if (key.objectid >= search_start) {
 109                         if (start_found) {
 110                                 if (last_ino < search_start)
 111                                         last_ino = search_start;
 112                                 hole_size = key.objectid - last_ino;
 113                                 if (hole_size > 0) {
 114                                         *objectid = last_ino;
 115                                         goto found;
 116                                 }
 117                         }
 118                 }
 119                 start_found = 1;
 120                 last_ino = key.objectid + 1;
 121                 path->slots[0]++;
 122         }
 123         // FIXME -ENOSPC
 124 found:
 125         root->last_inode_alloc = *objectid;
 126         btrfs_release_path(root, path);
 127         btrfs_free_path(path);
 128         BUG_ON(*objectid < search_start);
 129         return 0;
 130 error:
 131         btrfs_release_path(root, path);
 132         btrfs_free_path(path);
 133         return ret;
 134 }