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 *fs_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;
  22         int start_found;
  23         struct btrfs_leaf *l;
  24         struct btrfs_root *root = fs_root->fs_info->inode_root;
  25         struct btrfs_key search_key;
  26         u64 search_start = dirid;
  27
  28         if (fs_root->fs_info->last_inode_alloc_dirid == dirid)
  29                 search_start = fs_root->fs_info->last_inode_alloc;
  30
  31         if (search_start < BTRFS_FIRST_FREE_OBJECTID)
  32                 search_start = BTRFS_FIRST_FREE_OBJECTID;
  33         search_key.objectid = search_start;
  34         search_key.flags = 0;
  35         btrfs_set_key_type(&search_key, BTRFS_INODE_MAP_ITEM_KEY);
  36         search_key.offset = 0;
  37
  38         btrfs_init_path(&path);
  39         start_found = 0;
  40         ret = btrfs_search_slot(trans, root, &search_key, &path, 0, 0);
  41         if (ret < 0)
  42                 goto error;
  43
  44         if (path.slots[0] > 0)
  45                 path.slots[0]--;
  46
  47         while (1) {
  48                 l = &path.nodes[0]->leaf;
  49                 slot = path.slots[0];
  50                 if (slot >= btrfs_header_nritems(&l->header)) {
  51                         ret = btrfs_next_leaf(root, &path);
  52                         if (ret == 0)
  53                                 continue;
  54                         if (ret < 0)
  55                                 goto error;
  56                         if (!start_found) {
  57                                 *objectid = search_start;
  58                                 start_found = 1;
  59                                 goto found;
  60                         }
  61                         *objectid = last_ino > search_start ?
  62                                 last_ino : search_start;
  63                         goto found;
  64                 }
  65                 btrfs_disk_key_to_cpu(&key, &l->items[slot].key);
  66                 if (key.objectid >= search_start) {
  67                         if (start_found) {
  68                                 if (last_ino < search_start)
  69                                         last_ino = search_start;
  70                                 hole_size = key.objectid - last_ino;
  71                                 if (hole_size > 0) {
  72                                         *objectid = last_ino;
  73                                         goto found;
  74                                 }
  75                         }
  76                 }
  77                 start_found = 1;
  78                 last_ino = key.objectid + 1;
  79                 path.slots[0]++;
  80         }
  81         // FIXME -ENOSPC
  82 found:
  83         root->fs_info->last_inode_alloc = *objectid;
  84         root->fs_info->last_inode_alloc_dirid = dirid;
  85         btrfs_release_path(root, &path);
  86         BUG_ON(*objectid < search_start);
  87         return 0;
  88 error:
  89         btrfs_release_path(root, &path);
  90         return ret;
  91 }
  92
  93 int btrfs_insert_inode_map(struct btrfs_trans_handle *trans,
  94                            struct btrfs_root *fs_root,
  95                            u64 objectid, struct btrfs_key *location)
  96 {
  97         int ret = 0;
  98         struct btrfs_path path;
  99         struct btrfs_inode_map_item *inode_item;
 100         struct btrfs_key key;
 101         struct btrfs_root *inode_root = fs_root->fs_info->inode_root;
 102
 103         key.objectid = objectid;
 104         key.flags = 0;
 105         btrfs_set_key_type(&key, BTRFS_INODE_MAP_ITEM_KEY);
 106         key.offset = 0;
 107         btrfs_init_path(&path);
 108         ret = btrfs_insert_empty_item(trans, inode_root, &path, &key,
 109                                       sizeof(struct btrfs_inode_map_item));
 110         if (ret)
 111                 goto out;
 112
 113         inode_item = btrfs_item_ptr(&path.nodes[0]->leaf, path.slots[0],
 114                                   struct btrfs_inode_map_item);
 115         btrfs_cpu_key_to_disk(&inode_item->key, location);
 116 out:
 117         btrfs_release_path(inode_root, &path);
 118         return ret;
 119 }
 120
 121 int btrfs_lookup_inode_map(struct btrfs_trans_handle *trans,
 122                            struct btrfs_root *fs_root, struct btrfs_path *path,
 123                            u64 objectid, int mod)
 124 {
 125         int ret;
 126         struct btrfs_key key;
 127         int ins_len = mod < 0 ? -1 : 0;
 128         int cow = mod != 0;
 129         struct btrfs_root *inode_root = fs_root->fs_info->inode_root;
 130
 131         key.objectid = objectid;
 132         key.flags = 0;
 133         key.offset = 0;
 134         btrfs_set_key_type(&key, BTRFS_INODE_MAP_ITEM_KEY);
 135         ret = btrfs_search_slot(trans, inode_root, &key, path, ins_len, cow);
 136         return ret;
 137 }
 138