btrfs-progs: tune csum-change: add leaf based threshold

For "btrfstune --csum", currently we do the following operations in just
one transaction for each:

- Delete old data csums
- Change new data csums objectid

Both operation can modify up to GiB or even TiB level of metadata, doing
them in just one transaction is definitely going to cause problems.

This patch adds a leaf number based threshold (32 leaves), after
modifying/deleting this many leaves, we commit a transaction to avoid
huge amount of dirty leaves piling up.

Signed-off-by: Qu Wenruo <wqu@suse.com>
This commit is contained in:
Qu Wenruo 2024-06-19 14:34:12 +09:30 committed by David Sterba
parent 6f99038a5f
commit fdbab93ca5

View File

@ -371,29 +371,48 @@ static int generate_new_data_csums(struct btrfs_fs_info *fs_info, u16 new_csum_t
return generate_new_data_csums_range(fs_info, 0, new_csum_type);
}
/* After deleting/modifying this many leaves, commit a transaction. */
#define CSUM_CHANGE_LEAVES_THRESHOLD 32
static int delete_old_data_csums(struct btrfs_fs_info *fs_info)
{
struct btrfs_root *csum_root = btrfs_csum_root(fs_info, 0);
struct btrfs_trans_handle *trans;
struct btrfs_trans_handle *trans = 0;
struct btrfs_path path = { 0 };
struct btrfs_key last_key;
unsigned int deleted_leaves = 0;
int ret;
last_key.objectid = BTRFS_EXTENT_CSUM_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 delete old data csums: %m");
return ret;
}
while (true) {
int start_slot;
int nr;
if (deleted_leaves >= CSUM_CHANGE_LEAVES_THRESHOLD) {
UASSERT(trans);
ret = btrfs_commit_transaction(trans, csum_root);
if (ret < 0) {
errno = -ret;
error_msg(ERROR_MSG_COMMIT_TRANS,
"deleting old data csums: %m");
return ret;
}
trans = NULL;
deleted_leaves = 0;
}
if (!trans) {
trans = btrfs_start_transaction(csum_root, 1);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
errno = -ret;
error_msg(ERROR_MSG_START_TRANS,
"deleting old data csums: %m");
return ret;
}
}
ret = btrfs_search_slot(trans, csum_root, &last_key, &path, -1, 1);
if (ret < 0) {
errno = -ret;
@ -428,6 +447,7 @@ static int delete_old_data_csums(struct btrfs_fs_info *fs_info)
break;
}
btrfs_release_path(&path);
deleted_leaves++;
}
btrfs_release_path(&path);
if (ret < 0)
@ -445,9 +465,10 @@ static int delete_old_data_csums(struct btrfs_fs_info *fs_info)
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_trans_handle *trans = NULL;
struct btrfs_path path = { 0 };
struct btrfs_key last_key;
unsigned int changed_leaves = 0;
u64 super_flags;
int ret = 0;
@ -455,17 +476,32 @@ static int change_csum_objectids(struct btrfs_fs_info *fs_info)
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;
if (changed_leaves >= CSUM_CHANGE_LEAVES_THRESHOLD) {
UASSERT(trans);
ret = btrfs_commit_transaction(trans, csum_root);
if (ret < 0) {
errno = -ret;
error_msg(ERROR_MSG_COMMIT_TRANS,
"changing data csum objectid: %m");
return ret;
}
trans = NULL;
changed_leaves = 0;
}
if (!trans) {
trans = btrfs_start_transaction(csum_root, 1);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
errno = -ret;
error_msg(ERROR_MSG_START_TRANS,
"changing data csum objectid: %m");
return ret;
}
}
ret = btrfs_search_slot(trans, csum_root, &last_key, &path, 0, 1);
if (ret < 0)
goto out;