-/*
- * btrfs_add_log_tree adds a new per-subvolume log tree into the
- * tree of log tree roots. This must be called with a tree log transaction
- * running (see start_log_trans).
- */
-static int btrfs_add_log_tree(struct btrfs_trans_handle *trans,
- struct btrfs_root *root)
-{
- struct btrfs_key key;
- struct btrfs_root_item root_item;
- struct btrfs_inode_item *inode_item;
- struct extent_buffer *leaf;
- struct btrfs_root *new_root = root;
- int ret;
- u64 objectid = root->root_key.objectid;
-
- leaf = btrfs_alloc_free_block(trans, root, root->leafsize, 0,
- BTRFS_TREE_LOG_OBJECTID,
- trans->transid, 0, 0, 0);
- if (IS_ERR(leaf)) {
- ret = PTR_ERR(leaf);
- return ret;
- }
-
- btrfs_set_header_nritems(leaf, 0);
- btrfs_set_header_level(leaf, 0);
- btrfs_set_header_bytenr(leaf, leaf->start);
- btrfs_set_header_generation(leaf, trans->transid);
- btrfs_set_header_owner(leaf, BTRFS_TREE_LOG_OBJECTID);
-
- write_extent_buffer(leaf, root->fs_info->fsid,
- (unsigned long)btrfs_header_fsid(leaf),
- BTRFS_FSID_SIZE);
- btrfs_mark_buffer_dirty(leaf);
-
- inode_item = &root_item.inode;
- memset(inode_item, 0, sizeof(*inode_item));
- inode_item->generation = cpu_to_le64(1);
- inode_item->size = cpu_to_le64(3);
- inode_item->nlink = cpu_to_le32(1);
- inode_item->nbytes = cpu_to_le64(root->leafsize);
- inode_item->mode = cpu_to_le32(S_IFDIR | 0755);
-
- btrfs_set_root_bytenr(&root_item, leaf->start);
- btrfs_set_root_generation(&root_item, trans->transid);
- btrfs_set_root_level(&root_item, 0);
- btrfs_set_root_refs(&root_item, 0);
- btrfs_set_root_used(&root_item, 0);
-
- memset(&root_item.drop_progress, 0, sizeof(root_item.drop_progress));
- root_item.drop_level = 0;
-
- btrfs_tree_unlock(leaf);
- free_extent_buffer(leaf);
- leaf = NULL;
-
- btrfs_set_root_dirid(&root_item, 0);
-
- key.objectid = BTRFS_TREE_LOG_OBJECTID;
- key.offset = objectid;
- btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
- ret = btrfs_insert_root(trans, root->fs_info->log_root_tree, &key,
- &root_item);
- if (ret)
- goto fail;
-
- new_root = btrfs_read_fs_root_no_radix(root->fs_info->log_root_tree,
- &key);
- BUG_ON(!new_root);
-
- WARN_ON(root->log_root);
- root->log_root = new_root;
-
- /*
- * log trees do not get reference counted because they go away
- * before a real commit is actually done. They do store pointers
- * to file data extents, and those reference counts still get
- * updated (along with back refs to the log tree).
- */
- new_root->ref_cows = 0;
- new_root->last_trans = trans->transid;
-
- /*
- * we need to make sure the root block for this new tree
- * is marked as dirty in the dirty_log_pages tree. This
- * is how it gets flushed down to disk at tree log commit time.
- *
- * the tree logging mutex keeps others from coming in and changing
- * the new_root->node, so we can safely access it here
- */
- set_extent_dirty(&new_root->dirty_log_pages, new_root->node->start,
- new_root->node->start + new_root->node->len - 1,
- GFP_NOFS);
-
-fail:
- return ret;
-}
-