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         path = btrfs_alloc_path();
  35         BUG_ON(!path);
  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 = btrfs_buffer_leaf(path->nodes[0]);
  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         btrfs_free_path(path);
  85         BUG_ON(*objectid < search_start);
  86         return 0;
  87 error:
  88         btrfs_release_path(root, path);
  89         btrfs_free_path(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         path = btrfs_alloc_path();
 108         BUG_ON(!path);
 109         btrfs_init_path(path);
 110         ret = btrfs_insert_empty_item(trans, inode_root, path, &key,
 111                                       sizeof(struct btrfs_inode_map_item));
 112         if (ret)
 113                 goto out;
 114
 115         inode_item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
 116                                     path->slots[0], struct btrfs_inode_map_item);
 117         btrfs_cpu_key_to_disk(&inode_item->key, location);
 118         btrfs_mark_buffer_dirty(path->nodes[0]);
 119 out:
 120         btrfs_release_path(inode_root, path);
 121         btrfs_free_path(path);
 122         return ret;
 123 }
 124
 125 int btrfs_lookup_inode_map(struct btrfs_trans_handle *trans,
 126                            struct btrfs_root *fs_root, struct btrfs_path *path,
 127                            u64 objectid, int mod)
 128 {
 129         int ret;
 130         struct btrfs_key key;
 131         int ins_len = mod < 0 ? -1 : 0;
 132         int cow = mod != 0;
 133         struct btrfs_root *inode_root = fs_root->fs_info->inode_root;
 134
 135         key.objectid = objectid;
 136         key.flags = 0;
 137         key.offset = 0;
 138         btrfs_set_key_type(&key, BTRFS_INODE_MAP_ITEM_KEY);
 139         ret = btrfs_search_slot(trans, inode_root, &key, path, ins_len, cow);
 140         return ret;
 141 }
 142