btrfs-progs/common/root-tree-utils.h
Qu Wenruo d3cf350e21 btrfs-progs: introduce btrfs_rebuild_uuid_tree() for mkfs and btrfs-convert
Currently mkfs uses its own create_uuid_tree(), but that function is
only handling FS_TREE.  This means for btrfs-convert we do not generate
the uuid tree, nor add the UUID of the image subvolume.  This can be a
problem if we're going to support multiple subvolumes during mkfs time.

To address this, introduce a new helper, btrfs_rebuild_uuid_tree():

- Create a new uuid tree if there is not one

- Remove all the existing items from uuid tree

- Iterate through all subvolumes
  * If the subvolume has no valid UUID, regenerate one
  * Add the uuid entry for the subvolume UUID
  * If the subvolume has received UUID, also add it to UUID tree

By this, this new helper can handle all the uuid tree generation needs for:

- Current mkfs
  Only one uuid entry for FS_TREE

- Current btrfs-convert
  Only FS_TREE and the image subvolume

- Future multi-subvolume mkfs
  As we do the scan for all subvolumes.

- Future "btrfs rescue rebuild-uuid-tree"

Signed-off-by: Qu Wenruo <wqu@suse.com>
2024-07-30 20:02:56 +02:00

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C

/*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#ifndef __ROOT_TREE_UTILS_H__
#define __ROOT_TREE_UTILS_H__
#include "kernel-shared/transaction.h"
int btrfs_make_root_dir(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 objectid);
int btrfs_make_subvolume(struct btrfs_trans_handle *trans, u64 objectid);
int btrfs_link_subvolume(struct btrfs_trans_handle *trans,
struct btrfs_root *parent_root,
u64 parent_dir, const char *name,
int namelen, struct btrfs_root *subvol);
int btrfs_rebuild_uuid_tree(struct btrfs_fs_info *fs_info);
#endif