fs/btrfs/inode-map.c

   1 #include <linux/module.h>
   2 #include "ctree.h"
   3 #include "disk-io.h"
   4 #include "transaction.h"
   5
   6 /*
   7  * walks the btree of allocated inodes and find a hole.
   8  */
   9 int btrfs_find_free_objectid(struct btrfs_trans_handle *trans,
  10                              struct btrfs_root *fs_root,
  11                              u64 dirid, u64 *objectid)
  12 {
  13         struct btrfs_path path;
  14         struct btrfs_key key;
  15         int ret;
  16         u64 hole_size = 0;
  17         int slot = 0;
  18         u64 last_ino = 0;
  19         int start_found;
  20         struct btrfs_leaf *l;
  21         struct btrfs_root *root = fs_root->fs_info->inode_root;
  22         struct btrfs_key search_key;
  23         u64 search_start = dirid;
  24
  25         if (fs_root->fs_info->last_inode_alloc_dirid == dirid)
  26                 search_start = fs_root->fs_info->last_inode_alloc;
  27
  28         search_start = max(search_start, BTRFS_FIRST_FREE_OBJECTID);
  29         search_key.objectid = search_start;
  30         search_key.flags = 0;
  31         btrfs_set_key_type(&search_key, BTRFS_INODE_MAP_ITEM_KEY);
  32         search_key.offset = 0;
  33
  34         btrfs_init_path(&path);
  35         start_found = 0;
  36         ret = btrfs_search_slot(trans, root, &search_key, &path, 0, 0);
  37         if (ret < 0)
  38                 goto error;
  39
  40         if (path.slots[0] > 0)
  41                 path.slots[0]--;
  42
  43         while (1) {
  44                 l = btrfs_buffer_leaf(path.nodes[0]);
  45                 slot = path.slots[0];
  46                 if (slot >= btrfs_header_nritems(&l->header)) {
  47                         ret = btrfs_next_leaf(root, &path);
  48                         if (ret == 0)
  49                                 continue;
  50                         if (ret < 0)
  51                                 goto error;
  52                         if (!start_found) {
  53                                 *objectid = search_start;
  54                                 start_found = 1;
  55                                 goto found;
  56                         }
  57                         *objectid = last_ino > search_start ?
  58                                 last_ino : search_start;
  59                         goto found;
  60                 }
  61                 btrfs_disk_key_to_cpu(&key, &l->items[slot].key);
  62                 if (key.objectid >= search_start) {
  63                         if (start_found) {
  64                                 if (last_ino < search_start)
  65                                         last_ino = search_start;
  66                                 hole_size = key.objectid - last_ino;
  67                                 if (hole_size > 0) {
  68                                         *objectid = last_ino;
  69                                         goto found;
  70                                 }
  71                         }
  72                 }
  73                 start_found = 1;
  74                 last_ino = key.objectid + 1;
  75                 path.slots[0]++;
  76         }
  77         // FIXME -ENOSPC
  78 found:
  79         root->fs_info->last_inode_alloc = *objectid;
  80         root->fs_info->last_inode_alloc_dirid = dirid;
  81         btrfs_release_path(root, &path);
  82         BUG_ON(*objectid < search_start);
  83         return 0;
  84 error:
  85         btrfs_release_path(root, &path);
  86         return ret;
  87 }
  88
  89 int btrfs_insert_inode_map(struct btrfs_trans_handle *trans,
  90                            struct btrfs_root *fs_root,
  91                            u64 objectid, struct btrfs_key *location)
  92 {
  93         int ret = 0;
  94         struct btrfs_path path;
  95         struct btrfs_inode_map_item *inode_item;
  96         struct btrfs_key key;
  97         struct btrfs_root *inode_root = fs_root->fs_info->inode_root;
  98
  99         key.objectid = objectid;
 100         key.flags = 0;
 101         btrfs_set_key_type(&key, BTRFS_INODE_MAP_ITEM_KEY);
 102         key.offset = 0;
 103         btrfs_init_path(&path);
 104         ret = btrfs_insert_empty_item(trans, inode_root, &path, &key,
 105                                       sizeof(struct btrfs_inode_map_item));
 106         if (ret)
 107                 goto out;
 108
 109         inode_item = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]),
 110                                     path.slots[0], struct btrfs_inode_map_item);
 111         btrfs_cpu_key_to_disk(&inode_item->key, location);
 112         mark_buffer_dirty(path.nodes[0]);
 113 out:
 114         btrfs_release_path(inode_root, &path);
 115         return ret;
 116 }
 117
 118 int btrfs_lookup_inode_map(struct btrfs_trans_handle *trans,
 119                            struct btrfs_root *fs_root, struct btrfs_path *path,
 120                            u64 objectid, int mod)
 121 {
 122         int ret;
 123         struct btrfs_key key;
 124         int ins_len = mod < 0 ? -1 : 0;
 125         int cow = mod != 0;
 126         struct btrfs_root *inode_root = fs_root->fs_info->inode_root;
 127
 128         key.objectid = objectid;
 129         key.flags = 0;
 130         key.offset = 0;
 131         btrfs_set_key_type(&key, BTRFS_INODE_MAP_ITEM_KEY);
 132         ret = btrfs_search_slot(trans, inode_root, &key, path, ins_len, cow);
 133         return ret;
 134 }
 135