+static int create_subvol(struct btrfs_root *root, char *name, int namelen)
+{
+ struct btrfs_trans_handle *trans;
+ struct btrfs_key key;
+ struct btrfs_root_item root_item;
+ struct btrfs_inode_item *inode_item;
+ struct buffer_head *subvol;
+ struct btrfs_leaf *leaf;
+ struct btrfs_root *new_root;
+ struct inode *inode;
+ struct inode *dir;
+ int ret;
+ u64 objectid;
+ u64 new_dirid = BTRFS_FIRST_FREE_OBJECTID;
+
+ mutex_lock(&root->fs_info->fs_mutex);
+ trans = btrfs_start_transaction(root, 1);
+ BUG_ON(!trans);
+
+ subvol = btrfs_alloc_free_block(trans, root, 0);
+ if (subvol == NULL)
+ return -ENOSPC;
+ leaf = btrfs_buffer_leaf(subvol);
+ btrfs_set_header_nritems(&leaf->header, 0);
+ btrfs_set_header_level(&leaf->header, 0);
+ btrfs_set_header_blocknr(&leaf->header, bh_blocknr(subvol));
+ btrfs_set_header_generation(&leaf->header, trans->transid);
+ btrfs_set_header_owner(&leaf->header, root->root_key.objectid);
+ memcpy(leaf->header.fsid, root->fs_info->disk_super->fsid,
+ sizeof(leaf->header.fsid));
+ mark_buffer_dirty(subvol);
+
+ inode_item = &root_item.inode;
+ memset(inode_item, 0, sizeof(*inode_item));
+ btrfs_set_inode_generation(inode_item, 1);
+ btrfs_set_inode_size(inode_item, 3);
+ btrfs_set_inode_nlink(inode_item, 1);
+ btrfs_set_inode_nblocks(inode_item, 1);
+ btrfs_set_inode_mode(inode_item, S_IFDIR | 0755);
+
+ btrfs_set_root_blocknr(&root_item, bh_blocknr(subvol));
+ btrfs_set_root_refs(&root_item, 1);
+ brelse(subvol);
+ subvol = NULL;
+
+ ret = btrfs_find_free_objectid(trans, root->fs_info->tree_root,
+ 0, &objectid);
+ BUG_ON(ret);
+
+ btrfs_set_root_dirid(&root_item, new_dirid);
+
+ key.objectid = objectid;
+ key.offset = 1;
+ key.flags = 0;
+ btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
+ ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
+ &root_item);
+ BUG_ON(ret);
+
+ /*
+ * insert the directory item
+ */
+ key.offset = (u64)-1;
+ dir = root->fs_info->sb->s_root->d_inode;
+ ret = btrfs_insert_dir_item(trans, root->fs_info->tree_root,
+ name, namelen, dir->i_ino, &key, 0);
+ BUG_ON(ret);
+
+ ret = btrfs_commit_transaction(trans, root);
+ BUG_ON(ret);
+
+ new_root = btrfs_read_fs_root(root->fs_info, &key);
+ BUG_ON(!new_root);
+
+ trans = btrfs_start_transaction(new_root, 1);
+ BUG_ON(!trans);
+
+ inode = btrfs_new_inode(trans, new_root, new_dirid,
+ BTRFS_I(dir)->block_group, S_IFDIR | 0700);
+ inode->i_op = &btrfs_dir_inode_operations;
+ inode->i_fop = &btrfs_dir_file_operations;
+
+ ret = btrfs_make_empty_dir(trans, new_root, new_dirid, new_dirid);
+ BUG_ON(ret);
+
+ inode->i_nlink = 1;
+ inode->i_size = 6;
+ ret = btrfs_update_inode(trans, new_root, inode);
+ BUG_ON(ret);
+
+ ret = btrfs_commit_transaction(trans, new_root);
+ BUG_ON(ret);
+
+ iput(inode);
+
+ mutex_unlock(&root->fs_info->fs_mutex);
+ btrfs_btree_balance_dirty(root);
+ return 0;
+}
+
+static int create_snapshot(struct btrfs_root *root, char *name, int namelen)
+{
+ struct btrfs_trans_handle *trans;
+ struct btrfs_key key;
+ struct btrfs_root_item new_root_item;
+ int ret;
+ u64 objectid;
+
+ if (!root->ref_cows)
+ return -EINVAL;
+
+ mutex_lock(&root->fs_info->fs_mutex);
+ trans = btrfs_start_transaction(root, 1);
+ BUG_ON(!trans);
+
+ ret = btrfs_update_inode(trans, root, root->inode);
+ BUG_ON(ret);
+
+ ret = btrfs_find_free_objectid(trans, root->fs_info->tree_root,
+ 0, &objectid);
+ BUG_ON(ret);
+
+ memcpy(&new_root_item, &root->root_item,
+ sizeof(new_root_item));
+
+ key.objectid = objectid;
+ key.offset = 1;
+ key.flags = 0;
+ btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
+ btrfs_set_root_blocknr(&new_root_item, bh_blocknr(root->node));
+
+ ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
+ &new_root_item);
+ BUG_ON(ret);
+
+ /*
+ * insert the directory item
+ */
+ key.offset = (u64)-1;
+ ret = btrfs_insert_dir_item(trans, root->fs_info->tree_root,
+ name, namelen,
+ root->fs_info->sb->s_root->d_inode->i_ino,
+ &key, 0);
+
+ BUG_ON(ret);
+
+ ret = btrfs_inc_root_ref(trans, root);
+ BUG_ON(ret);
+
+ ret = btrfs_commit_transaction(trans, root);
+ BUG_ON(ret);
+ mutex_unlock(&root->fs_info->fs_mutex);
+ btrfs_btree_balance_dirty(root);
+ return 0;
+}
+
+static int add_disk(struct btrfs_root *root, char *name, int namelen)
+{
+ struct block_device *bdev;
+ struct btrfs_path *path;
+ struct super_block *sb = root->fs_info->sb;
+ struct btrfs_root *dev_root = root->fs_info->dev_root;
+ struct btrfs_trans_handle *trans;
+ struct btrfs_device_item *dev_item;
+ struct btrfs_key key;
+ u16 item_size;
+ u64 num_blocks;
+ u64 new_blocks;
+ u64 device_id;
+ int ret;
+
+printk("adding disk %s\n", name);
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+ num_blocks = btrfs_super_total_blocks(root->fs_info->disk_super);
+ bdev = open_bdev_excl(name, O_RDWR, sb);
+ if (IS_ERR(bdev)) {
+ ret = PTR_ERR(bdev);
+printk("open bdev excl failed ret %d\n", ret);
+ goto out_nolock;
+ }
+ set_blocksize(bdev, sb->s_blocksize);
+ new_blocks = bdev->bd_inode->i_size >> sb->s_blocksize_bits;
+ key.objectid = num_blocks;
+ key.offset = new_blocks;
+ key.flags = 0;
+ btrfs_set_key_type(&key, BTRFS_DEV_ITEM_KEY);
+
+ mutex_lock(&dev_root->fs_info->fs_mutex);
+ trans = btrfs_start_transaction(dev_root, 1);
+ item_size = sizeof(*dev_item) + namelen;
+printk("insert empty on %Lu %Lu %u size %d\n", num_blocks, new_blocks, key.flags, item_size);
+ ret = btrfs_insert_empty_item(trans, dev_root, path, &key, item_size);
+ if (ret) {
+printk("insert failed %d\n", ret);
+ close_bdev_excl(bdev);
+ if (ret > 0)
+ ret = -EEXIST;
+ goto out;
+ }
+ dev_item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
+ path->slots[0], struct btrfs_device_item);
+ btrfs_set_device_pathlen(dev_item, namelen);
+ memcpy(dev_item + 1, name, namelen);
+
+ device_id = btrfs_super_last_device_id(root->fs_info->disk_super) + 1;
+ btrfs_set_super_last_device_id(root->fs_info->disk_super, device_id);
+ btrfs_set_device_id(dev_item, device_id);
+ mark_buffer_dirty(path->nodes[0]);
+
+ ret = btrfs_insert_dev_radix(root, bdev, device_id, num_blocks,
+ new_blocks);
+
+ if (!ret) {
+ btrfs_set_super_total_blocks(root->fs_info->disk_super,
+ num_blocks + new_blocks);
+ i_size_write(root->fs_info->btree_inode,
+ (num_blocks + new_blocks) <<
+ root->fs_info->btree_inode->i_blkbits);
+ }
+
+out:
+ ret = btrfs_commit_transaction(trans, dev_root);
+ BUG_ON(ret);
+ mutex_unlock(&root->fs_info->fs_mutex);
+out_nolock:
+ btrfs_free_path(path);
+ btrfs_btree_balance_dirty(root);
+
+ return ret;
+}
+
+static int btrfs_ioctl(struct inode *inode, struct file *filp, unsigned int
+ cmd, unsigned long arg)
+{
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ struct btrfs_ioctl_vol_args vol_args;
+ int ret = 0;
+ struct btrfs_dir_item *di;
+ int namelen;
+ struct btrfs_path *path;
+ u64 root_dirid;
+
+ switch (cmd) {
+ case BTRFS_IOC_SNAP_CREATE:
+ if (copy_from_user(&vol_args,
+ (struct btrfs_ioctl_vol_args __user *)arg,
+ sizeof(vol_args)))
+ return -EFAULT;
+ namelen = strlen(vol_args.name);
+ if (namelen > BTRFS_VOL_NAME_MAX)
+ return -EINVAL;
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+ root_dirid = root->fs_info->sb->s_root->d_inode->i_ino,
+ mutex_lock(&root->fs_info->fs_mutex);
+ di = btrfs_lookup_dir_item(NULL, root->fs_info->tree_root,
+ path, root_dirid,
+ vol_args.name, namelen, 0);
+ mutex_unlock(&root->fs_info->fs_mutex);
+ btrfs_free_path(path);
+ if (di && !IS_ERR(di))
+ return -EEXIST;
+
+ if (root == root->fs_info->tree_root)
+ ret = create_subvol(root, vol_args.name, namelen);
+ else
+ ret = create_snapshot(root, vol_args.name, namelen);
+ WARN_ON(ret);
+ break;
+ case BTRFS_IOC_ADD_DISK:
+ if (copy_from_user(&vol_args,
+ (struct btrfs_ioctl_vol_args __user *)arg,
+ sizeof(vol_args)))
+ return -EFAULT;
+ namelen = strlen(vol_args.name);
+ if (namelen > BTRFS_VOL_NAME_MAX)
+ return -EINVAL;
+ vol_args.name[namelen] = '\0';
+ ret = add_disk(root, vol_args.name, namelen);
+ break;
+ default:
+ return -ENOTTY;
+ }
+ return ret;
+}
+