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>
This commit is contained in:
Qu Wenruo 2024-07-26 16:59:10 +09:30 committed by David Sterba
parent 99dc37bcfe
commit d3cf350e21
4 changed files with 287 additions and 34 deletions

View File

@ -15,9 +15,11 @@
*/
#include <time.h>
#include <uuid/uuid.h>
#include "common/root-tree-utils.h"
#include "common/messages.h"
#include "kernel-shared/disk-io.h"
#include "kernel-shared/uuid-tree.h"
int btrfs_make_root_dir(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 objectid)
@ -212,3 +214,279 @@ abort:
btrfs_abort_transaction(trans, ret);
return ret;
}
static int remove_all_tree_items(struct btrfs_root *root)
{
struct btrfs_trans_handle *trans;
struct btrfs_path path = { 0 };
struct btrfs_key key = { 0 };
int ret;
trans = btrfs_start_transaction(root, 1);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
errno = -ret;
error_msg(ERROR_MSG_START_TRANS,
"remove all items for tree %lld: %m",
root->root_key.objectid);
return ret;
}
while (true) {
int nr_items;
ret = btrfs_search_slot(trans, root, &key, &path, -1, 1);
if (ret < 0) {
errno = -ret;
error("failed to locate the first key of root %lld: %m",
root->root_key.objectid);
btrfs_abort_transaction(trans, ret);
return ret;
}
if (ret == 0) {
ret = -EUCLEAN;
errno = -ret;
error("unexpected all zero key found in root %lld",
root->root_key.objectid);
btrfs_abort_transaction(trans, ret);
return ret;
}
nr_items = btrfs_header_nritems(path.nodes[0]);
/* The tree is empty. */
if (nr_items == 0) {
btrfs_release_path(&path);
break;
}
ret = btrfs_del_items(trans, root, &path, 0, nr_items);
btrfs_release_path(&path);
if (ret < 0) {
errno = -ret;
error("failed to empty the first leaf of root %lld: %m",
root->root_key.objectid);
btrfs_abort_transaction(trans, ret);
return ret;
}
}
ret = btrfs_commit_transaction(trans, root);
if (ret < 0) {
errno = -ret;
error_msg(ERROR_MSG_COMMIT_TRANS,
"removal all items for tree %lld: %m",
root->root_key.objectid);
}
return ret;
}
static int rescan_subvol_uuid(struct btrfs_trans_handle *trans,
struct btrfs_key *subvol_key)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_root *subvol;
int ret;
UASSERT(is_fstree(subvol_key->objectid));
/*
* Read out the subvolume root and updates root::root_item.
* This is to avoid de-sync between in-memory and on-disk root_items.
*/
subvol = btrfs_read_fs_root(fs_info, subvol_key);
if (IS_ERR(subvol)) {
ret = PTR_ERR(subvol);
error("failed to read subvolume %llu: %m",
subvol_key->objectid);
btrfs_abort_transaction(trans, ret);
return ret;
}
/* The uuid is not set, regenerate one. */
if (uuid_is_null(subvol->root_item.uuid)) {
uuid_generate(subvol->root_item.uuid);
ret = btrfs_update_root(trans, fs_info->tree_root, &subvol->root_key,
&subvol->root_item);
if (ret < 0) {
error("failed to update subvolume %llu: %m",
subvol_key->objectid);
btrfs_abort_transaction(trans, ret);
return ret;
}
}
ret = btrfs_uuid_tree_add(trans, subvol->root_item.uuid,
BTRFS_UUID_KEY_SUBVOL,
subvol->root_key.objectid);
if (ret < 0) {
errno = -ret;
error("failed to add uuid for subvolume %llu: %m",
subvol_key->objectid);
btrfs_abort_transaction(trans, ret);
return ret;
}
if (!uuid_is_null(subvol->root_item.received_uuid)) {
ret = btrfs_uuid_tree_add(trans, subvol->root_item.uuid,
BTRFS_UUID_KEY_RECEIVED_SUBVOL,
subvol->root_key.objectid);
if (ret < 0) {
errno = -ret;
error("failed to add received_uuid for subvol %llu: %m",
subvol->root_key.objectid);
btrfs_abort_transaction(trans, ret);
return ret;
}
}
return 0;
}
static int rescan_uuid_tree(struct btrfs_fs_info *fs_info)
{
struct btrfs_root *tree_root = fs_info->tree_root;
struct btrfs_root *uuid_root = fs_info->uuid_root;
struct btrfs_trans_handle *trans;
struct btrfs_path path = { 0 };
struct btrfs_key key = { 0 };
int ret;
UASSERT(uuid_root);
trans = btrfs_start_transaction(uuid_root, 1);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
errno = -ret;
error_msg(ERROR_MSG_START_TRANS, "rescan uuid tree: %m");
return ret;
}
key.objectid = BTRFS_LAST_FREE_OBJECTID;
key.type = BTRFS_ROOT_ITEM_KEY;
key.offset = (u64)-1;
/* Iterate through all subvolumes except fs tree. */
while (true) {
struct btrfs_key found_key;
struct extent_buffer *leaf;
int slot;
/* No more subvolume. */
if (key.objectid < BTRFS_FIRST_FREE_OBJECTID) {
ret = 0;
break;
}
ret = btrfs_search_slot(NULL, tree_root, &key, &path, 0, 0);
if (ret < 0) {
errno = -ret;
error_msg(ERROR_MSG_READ, "iterate subvolumes: %m");
btrfs_abort_transaction(trans, ret);
return ret;
}
if (ret > 0) {
ret = btrfs_previous_item(tree_root, &path,
BTRFS_FIRST_FREE_OBJECTID,
BTRFS_ROOT_ITEM_KEY);
if (ret < 0) {
errno = -ret;
btrfs_release_path(&path);
error_msg(ERROR_MSG_READ, "iterate subvolumes: %m");
btrfs_abort_transaction(trans, ret);
return ret;
}
/* No more subvolume. */
if (ret > 0) {
ret = 0;
btrfs_release_path(&path);
break;
}
}
leaf = path.nodes[0];
slot = path.slots[0];
btrfs_item_key_to_cpu(leaf, &found_key, slot);
btrfs_release_path(&path);
key.objectid = found_key.objectid - 1;
ret = rescan_subvol_uuid(trans, &found_key);
if (ret < 0) {
errno = -ret;
error("failed to rescan the uuid of subvolume %llu: %m",
found_key.objectid);
btrfs_abort_transaction(trans, ret);
return ret;
}
}
/* Update fs tree uuid. */
key.objectid = BTRFS_FS_TREE_OBJECTID;
key.type = BTRFS_ROOT_ITEM_KEY;
key.offset = 0;
ret = rescan_subvol_uuid(trans, &key);
if (ret < 0) {
errno = -ret;
error("failed to rescan the uuid of subvolume %llu: %m",
key.objectid);
btrfs_abort_transaction(trans, ret);
return ret;
}
ret = btrfs_commit_transaction(trans, uuid_root);
if (ret < 0) {
errno = -ret;
error_msg(ERROR_MSG_COMMIT_TRANS, "rescan uuid tree: %m");
}
return ret;
}
/*
* Rebuild the whole uuid tree.
*
* If no uuid tree is present, create a new one.
* If there is an existing uuid tree, all items will be deleted first.
*
* For all existing subvolumes (except fs tree), any uninitialized uuid
* (all zero) will be generated using a random uuid, and inserted into the new
* tree.
* And if a subvolume has its UUID initialized, it will not be touched and
* added to the new uuid tree.
*/
int btrfs_rebuild_uuid_tree(struct btrfs_fs_info *fs_info)
{
struct btrfs_root *uuid_root;
struct btrfs_key key;
int ret;
if (!fs_info->uuid_root) {
struct btrfs_trans_handle *trans;
trans = btrfs_start_transaction(fs_info->tree_root, 1);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
errno = -ret;
error_msg(ERROR_MSG_START_TRANS, "create uuid tree: %m");
return ret;
}
key.objectid = BTRFS_UUID_TREE_OBJECTID;
key.type = BTRFS_ROOT_ITEM_KEY;
key.offset = 0;
uuid_root = btrfs_create_tree(trans, &key);
if (IS_ERR(uuid_root)) {
ret = PTR_ERR(uuid_root);
errno = -ret;
error("failed to create uuid root: %m");
btrfs_abort_transaction(trans, ret);
return ret;
}
add_root_to_dirty_list(uuid_root);
fs_info->uuid_root = uuid_root;
ret = btrfs_commit_transaction(trans, fs_info->tree_root);
if (ret < 0) {
errno = -ret;
error_msg(ERROR_MSG_COMMIT_TRANS, "create uuid tree: %m");
return ret;
}
} else {
ret = remove_all_tree_items(fs_info->uuid_root);
if (ret < 0) {
errno = -ret;
error("failed to clear the existing uuid tree: %m");
return ret;
}
}
UASSERT(fs_info->uuid_root);
ret = rescan_uuid_tree(fs_info);
if (ret < 0) {
errno = -ret;
error("failed to rescan the uuid tree: %m");
return ret;
}
return 0;
}

View File

@ -26,5 +26,6 @@ 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

View File

@ -1339,6 +1339,11 @@ static int do_convert(const char *devname, u32 convert_flags, u32 nodesize,
goto fail;
}
ret = btrfs_rebuild_uuid_tree(image_root->fs_info);
if (ret < 0) {
errno = -ret;
goto fail;
}
memset(root->fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
if (convert_flags & CONVERT_FLAG_COPY_LABEL) {
strncpy_null(root->fs_info->super_copy->label, cctx.label, BTRFS_LABEL_SIZE);

View File

@ -736,35 +736,6 @@ static void update_chunk_allocation(struct btrfs_fs_info *fs_info,
}
}
static int create_uuid_tree(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_root *root;
struct btrfs_key key = {
.objectid = BTRFS_UUID_TREE_OBJECTID,
.type = BTRFS_ROOT_ITEM_KEY,
};
int ret = 0;
UASSERT(fs_info->uuid_root == NULL);
root = btrfs_create_tree(trans, &key);
if (IS_ERR(root)) {
ret = PTR_ERR(root);
goto out;
}
add_root_to_dirty_list(root);
fs_info->uuid_root = root;
ret = btrfs_uuid_tree_add(trans, fs_info->fs_root->root_item.uuid,
BTRFS_UUID_KEY_SUBVOL,
fs_info->fs_root->root_key.objectid);
if (ret < 0)
btrfs_abort_transaction(trans, ret);
out:
return ret;
}
static int create_global_root(struct btrfs_trans_handle *trans, u64 objectid,
int root_id)
{
@ -1822,17 +1793,15 @@ raid_groups:
goto out;
}
ret = create_uuid_tree(trans);
if (ret)
warning(
"unable to create uuid tree, will be created after mount: %d", ret);
ret = btrfs_commit_transaction(trans, root);
if (ret) {
errno = -ret;
error_msg(ERROR_MSG_START_TRANS, "%m");
goto out;
}
ret = btrfs_rebuild_uuid_tree(fs_info);
if (ret < 0)
goto out;
ret = cleanup_temp_chunks(fs_info, &allocation, data_profile,
metadata_profile, metadata_profile);