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