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btrfs-progs: tune: add the ability to migrate the temporary csum items to regular csum items

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At this stage, the csum tree should only contain the temporary csum
items (CSUM_CHANGE, EXTENT_CSUM, logical), and no more old csum items.

Now we can convert those temporary csum items back to regular csum items
by changing their key objectids back to EXTENT_CSUM.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Qu Wenruo 2023-05-18 10:10:44 +08:00 committed by David Sterba
parent 4cf02fbc84
commit 87016bffbb
1 changed files with 86 additions and 0 deletions
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86
tune/change-csum.c
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@ -388,6 +388,89 @@ static int delete_old_data_csums(struct btrfs_fs_info *fs_info)
return ret;
}
static int change_csum_objectids(struct btrfs_fs_info *fs_info)
{
struct btrfs_root *csum_root = btrfs_csum_root(fs_info, 0);
struct btrfs_trans_handle *trans;
struct btrfs_path path = { 0 };
struct btrfs_key last_key;
u64 super_flags;
int ret = 0;
last_key.objectid = BTRFS_CSUM_CHANGE_OBJECTID;
last_key.type = BTRFS_EXTENT_CSUM_KEY;
last_key.offset = (u64)-1;
trans = btrfs_start_transaction(csum_root, 1);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
errno = -ret;
error("failed to start transaction to change csum objectids: %m");
return ret;
}
while (true) {
struct btrfs_key found_key;
int nr;
ret = btrfs_search_slot(trans, csum_root, &last_key, &path, 0, 1);
if (ret < 0)
goto out;
assert(ret > 0);
nr = btrfs_header_nritems(path.nodes[0]);
/* No item left (empty csum tree), exit. */
if (!nr)
goto out;
/* No more temporary csum items, all converted, exit. */
if (path.slots[0] == 0)
goto out;
/* All csum items should be new csums. */
btrfs_item_key_to_cpu(path.nodes[0], &found_key, 0);
assert(found_key.objectid == BTRFS_CSUM_CHANGE_OBJECTID);
/*
* Start changing the objectids, since EXTENT_CSUM (-10) is
* larger than CSUM_CHANGE (-13), we always change from the tail.
*/
for (int i = nr - 1; i >= 0; i--) {
btrfs_item_key_to_cpu(path.nodes[0], &found_key, i);
found_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
path.slots[0] = i;
ret = btrfs_set_item_key_safe(csum_root, &path, &found_key);
if (ret < 0) {
errno = -ret;
error("failed to set item key for data csum at logical %llu: %m",
found_key.offset);
goto out;
}
}
btrfs_release_path(&path);
}
out:
btrfs_release_path(&path);
if (ret < 0) {
btrfs_abort_transaction(trans, ret);
return ret;
}
/*
* All data csum items has been changed to the new type, we can clear
* the superblock flag for data csum change, and go to the metadata csum
* change phase.
*/
super_flags = btrfs_super_flags(fs_info->super_copy);
super_flags &= ~BTRFS_SUPER_FLAG_CHANGING_DATA_CSUM;
super_flags |= BTRFS_SUPER_FLAG_CHANGING_META_CSUM;
btrfs_set_super_flags(fs_info->super_copy, super_flags);
ret = btrfs_commit_transaction(trans, csum_root);
if (ret < 0) {
errno = -ret;
error("failed to commit transaction after changing data csum objectids: %m");
}
return ret;
}
int btrfs_change_csum_type(struct btrfs_fs_info *fs_info, u16 new_csum_type)
{
int ret;
@ -417,6 +500,9 @@ int btrfs_change_csum_type(struct btrfs_fs_info *fs_info, u16 new_csum_type)
return ret;
/* Phase 3, change the new csum key objectid */
ret = change_csum_objectids(fs_info);
if (ret < 0)
return ret;
/*
* Phase 4, change the csums for metadata.