inode-map.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include "kerncompat.h"
   4 #include "radix-tree.h"
   5 #include "ctree.h"
   6 #include "disk-io.h"
   7 #include "transaction.h"
   8
   9 /*
  10  * walks the btree of allocated inodes and find a hole.
  11  */
  12 int btrfs_find_free_objectid(struct btrfs_trans_handle *trans,
  13                              struct btrfs_root *root,
  14                              u64 dirid, u64 *objectid)
  15 {
  16         struct btrfs_path path;
  17         struct btrfs_key key;
  18         int ret;
  19         u64 hole_size = 0;
  20         int slot = 0;
  21         u64 last_ino = 0;
  22         int start_found;
  23         struct btrfs_leaf *l;
  24         struct btrfs_key search_key;
  25         u64 search_start = dirid;
  26
  27         if (root->fs_info->last_inode_alloc_dirid == dirid)
  28                 search_start = root->fs_info->last_inode_alloc;
  29
  30         if (search_start < BTRFS_FIRST_FREE_OBJECTID)
  31                 search_start = BTRFS_FIRST_FREE_OBJECTID;
  32         search_key.objectid = search_start;
  33         search_key.flags = 0;
  34         search_key.offset = 0;
  35
  36         btrfs_init_path(&path);
  37         start_found = 0;
  38         ret = btrfs_search_slot(trans, root, &search_key, &path, 0, 0);
  39         if (ret < 0)
  40                 goto error;
  41
  42         if (path.slots[0] > 0)
  43                 path.slots[0]--;
  44
  45         while (1) {
  46                 l = &path.nodes[0]->leaf;
  47                 slot = path.slots[0];
  48                 if (slot >= btrfs_header_nritems(&l->header)) {
  49                         ret = btrfs_next_leaf(root, &path);
  50                         if (ret == 0)
  51                                 continue;
  52                         if (ret < 0)
  53                                 goto error;
  54                         if (!start_found) {
  55                                 *objectid = search_start;
  56                                 start_found = 1;
  57                                 goto found;
  58                         }
  59                         *objectid = last_ino > search_start ?
  60                                 last_ino : search_start;
  61                         goto found;
  62                 }
  63                 btrfs_disk_key_to_cpu(&key, &l->items[slot].key);
  64                 if (key.objectid >= search_start) {
  65                         if (start_found) {
  66                                 if (last_ino < search_start)
  67                                         last_ino = search_start;
  68                                 hole_size = key.objectid - last_ino;
  69                                 if (hole_size > 0) {
  70                                         *objectid = last_ino;
  71                                         goto found;
  72                                 }
  73                         }
  74                 }
  75                 start_found = 1;
  76                 last_ino = key.objectid + 1;
  77                 path.slots[0]++;
  78         }
  79         // FIXME -ENOSPC
  80 found:
  81         root->fs_info->last_inode_alloc = *objectid;
  82         root->fs_info->last_inode_alloc_dirid = dirid;
  83         btrfs_release_path(root, &path);
  84         BUG_ON(*objectid < search_start);
  85         return 0;
  86 error:
  87         btrfs_release_path(root, &path);
  88         return ret;
  89 }