btrfs-progs/tune/change-csum.c
David Sterba 316f221908 btrfs-progs: btrfstune: add injection points to btrfsune --csum
Add points after each commit when changing the checksum type.

Signed-off-by: David Sterba <dsterba@suse.com>
2023-07-27 14:45:29 +02:00

1080 lines
29 KiB
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.
*/
#include "kerncompat.h"
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include "kernel-shared/ctree.h"
#include "kernel-shared/disk-io.h"
#include "kernel-shared/volumes.h"
#include "kernel-shared/file-item.h"
#include "kernel-shared/extent_io.h"
#include "kernel-shared/transaction.h"
#include "common/messages.h"
#include "common/internal.h"
#include "common/utils.h"
#include "common/inject-error.h"
#include "tune/tune.h"
static int check_csum_change_requreiment(struct btrfs_fs_info *fs_info, u16 new_csum_type)
{
struct btrfs_root *tree_root = fs_info->tree_root;
struct btrfs_root *dev_root = fs_info->dev_root;
struct btrfs_path path = { 0 };
struct btrfs_key key;
int ret;
if (btrfs_super_log_root(fs_info->super_copy)) {
error("dirty log tree detected, please replay the log or zero it.");
return -EINVAL;
}
if (btrfs_fs_incompat(fs_info, EXTENT_TREE_V2)) {
error("no csum change support for extent-tree-v2 feature yet.");
return -EOPNOTSUPP;
}
key.objectid = BTRFS_BALANCE_OBJECTID;
key.type = BTRFS_TEMPORARY_ITEM_KEY;
key.offset = 0;
ret = btrfs_search_slot(NULL, tree_root, &key, &path, 0, 0);
btrfs_release_path(&path);
if (ret < 0) {
errno = -ret;
error("failed to check the balance status: %m");
return ret;
}
if (ret == 0) {
error("running balance detected, please finish or cancel it.");
return -EINVAL;
}
key.objectid = 0;
key.type = BTRFS_DEV_REPLACE_KEY;
key.offset = 0;
ret = btrfs_search_slot(NULL, dev_root, &key, &path, 0, 0);
btrfs_release_path(&path);
if (ret < 0) {
errno = -ret;
error("failed to check the dev-reaplce status: %m");
return ret;
}
if (ret == 0) {
error("running dev-replace detected, please finish or cancel it.");
return -EINVAL;
}
if (fs_info->csum_type == new_csum_type) {
error("the fs is already using csum type %s (%u)",
btrfs_super_csum_name(new_csum_type), new_csum_type);
return -EINVAL;
}
return 0;
}
static int get_last_csum_bytenr(struct btrfs_fs_info *fs_info, u64 *result)
{
struct btrfs_root *csum_root = btrfs_csum_root(fs_info, 0);
struct btrfs_path path = { 0 };
struct btrfs_key key;
int ret;
key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
key.type = BTRFS_EXTENT_CSUM_KEY;
key.offset = (u64)-1;
ret = btrfs_search_slot(NULL, csum_root, &key, &path, 0, 0);
if (ret < 0)
return ret;
assert(ret > 0);
ret = btrfs_previous_item(csum_root, &path, BTRFS_EXTENT_CSUM_OBJECTID,
BTRFS_EXTENT_CSUM_KEY);
if (ret < 0)
return ret;
/*
* Emptry csum tree, set last csum byte to 0 so we can skip new data
* csum generation.
*/
if (ret > 0) {
*result = 0;
btrfs_release_path(&path);
return 0;
}
btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
*result = key.offset + btrfs_item_size(path.nodes[0], path.slots[0]) /
fs_info->csum_size * fs_info->sectorsize;
btrfs_release_path(&path);
return 0;
}
static int read_verify_one_data_sector(struct btrfs_fs_info *fs_info,
u64 logical, void *data_buf,
const void *old_csums, u16 old_csum_type,
bool output_error)
{
const u32 sectorsize = fs_info->sectorsize;
int num_copies = btrfs_num_copies(fs_info, logical, sectorsize);
bool found_good = false;
for (int mirror = 1; mirror <= num_copies; mirror++) {
u8 csum_has[BTRFS_CSUM_SIZE];
u64 readlen = sectorsize;
int ret;
ret = read_data_from_disk(fs_info, data_buf, logical, &readlen,
mirror);
if (ret < 0) {
errno = -ret;
error("failed to read logical %llu: %m", logical);
continue;
}
btrfs_csum_data(fs_info, fs_info->csum_type, data_buf, csum_has,
sectorsize);
if (memcmp(csum_has, old_csums, fs_info->csum_size) == 0) {
found_good = true;
break;
} else if (output_error){
char found[BTRFS_CSUM_STRING_LEN];
char want[BTRFS_CSUM_STRING_LEN];
btrfs_format_csum(fs_info->csum_type, old_csums, want);
btrfs_format_csum(fs_info->csum_type, csum_has, found);
error("csum mismatch for logical %llu mirror %u, has %s expected %s",
logical, mirror, found, want);
}
}
if (!found_good)
return -EIO;
return 0;
}
static int generate_new_csum_range(struct btrfs_trans_handle *trans,
u64 logical, u64 length, u16 new_csum_type,
const void *old_csums)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
const u32 sectorsize = fs_info->sectorsize;
int ret = 0;
void *buf;
buf = malloc(fs_info->sectorsize);
if (!buf)
return -ENOMEM;
for (u64 cur = logical; cur < logical + length; cur += sectorsize) {
ret = read_verify_one_data_sector(fs_info, cur, buf, old_csums +
(cur - logical) / sectorsize * fs_info->csum_size,
fs_info->csum_type, true);
if (ret < 0) {
error("failed to recover a good copy for data at logical %llu",
logical);
goto out;
}
/* Calculate new csum and insert it into the csum tree. */
ret = btrfs_csum_file_block(trans, cur,
BTRFS_CSUM_CHANGE_OBJECTID, new_csum_type, buf);
if (ret < 0) {
errno = -ret;
error("failed to insert new csum for data at logical %llu: %m",
cur);
goto out;
}
}
out:
free(buf);
return ret;
}
/*
* After reading this many bytes of data, commit the current transaction.
*
* Only a soft cap, we can exceed the threshold if hitting a large enough csum
* item.
*/
#define CSUM_CHANGE_BYTES_THRESHOLD (SZ_2M)
static int generate_new_data_csums_range(struct btrfs_fs_info *fs_info, u64 start,
u16 new_csum_type)
{
struct btrfs_root *csum_root = btrfs_csum_root(fs_info, 0);
struct btrfs_trans_handle *trans;
struct btrfs_path path = { 0 };
struct btrfs_key key;
const u32 new_csum_size = btrfs_csum_type_size(new_csum_type);
void *csum_buffer;
u64 converted_bytes = 0;
u64 last_csum;
u64 cur = start;
int ret;
ret = get_last_csum_bytenr(fs_info, &last_csum);
if (ret < 0) {
errno = -ret;
error("failed to get the last csum item: %m");
return ret;
}
csum_buffer = malloc(fs_info->nodesize);
if (!csum_buffer)
return -ENOMEM;
trans = btrfs_start_transaction(csum_root,
CSUM_CHANGE_BYTES_THRESHOLD / fs_info->sectorsize *
new_csum_size);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
errno = -ret;
error("failed to start transaction: %m");
return ret;
}
while (cur < last_csum) {
u64 start;
u64 len;
u32 item_size;
key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
key.type = BTRFS_EXTENT_CSUM_KEY;
key.offset = cur;
ret = btrfs_search_slot(NULL, csum_root, &key, &path, 0, 0);
if (ret < 0)
goto out;
if (ret > 0 && path.slots[0] >=
btrfs_header_nritems(path.nodes[0])) {
ret = btrfs_next_leaf(csum_root, &path);
if (ret > 0) {
ret = 0;
btrfs_release_path(&path);
break;
}
if (ret < 0) {
btrfs_release_path(&path);
goto out;
}
}
btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
assert(key.offset >= cur);
item_size = btrfs_item_size(path.nodes[0], path.slots[0]);
start = key.offset;
len = item_size / fs_info->csum_size * fs_info->sectorsize;
read_extent_buffer(path.nodes[0], csum_buffer,
btrfs_item_ptr_offset(path.nodes[0], path.slots[0]),
item_size);
btrfs_release_path(&path);
ret = generate_new_csum_range(trans, start, len, new_csum_type,
csum_buffer);
if (ret < 0)
goto out;
converted_bytes += len;
if (converted_bytes >= CSUM_CHANGE_BYTES_THRESHOLD) {
converted_bytes = 0;
ret = btrfs_commit_transaction(trans, csum_root);
if (inject_error(0xfc35ae54))
return -EUCLEAN;
if (ret < 0)
goto out;
trans = btrfs_start_transaction(csum_root,
CSUM_CHANGE_BYTES_THRESHOLD /
fs_info->sectorsize * new_csum_size);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
goto out;
}
}
cur = start + len;
}
ret = btrfs_commit_transaction(trans, csum_root);
if (inject_error(0x4de02239))
return -EUCLEAN;
out:
free(csum_buffer);
return ret;
}
static int generate_new_data_csums(struct btrfs_fs_info *fs_info, u16 new_csum_type)
{
struct btrfs_root *tree_root = fs_info->tree_root;
struct btrfs_trans_handle *trans;
struct btrfs_path path = { 0 };
struct btrfs_key key;
int ret;
trans = btrfs_start_transaction(tree_root, 1);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
errno = -ret;
error("failed to start transaction: %m");
return ret;
}
key.objectid = BTRFS_CSUM_CHANGE_OBJECTID;
key.type = BTRFS_TEMPORARY_ITEM_KEY;
key.offset = new_csum_type;
ret = btrfs_insert_empty_item(trans, tree_root, &path, &key, 0);
btrfs_release_path(&path);
if (ret < 0) {
errno = -ret;
error("failed to insert csum change item: %m");
btrfs_abort_transaction(trans, ret);
return ret;
}
btrfs_set_super_flags(fs_info->super_copy,
btrfs_super_flags(fs_info->super_copy) |
BTRFS_SUPER_FLAG_CHANGING_DATA_CSUM);
ret = btrfs_commit_transaction(trans, tree_root);
if (inject_error(0x3964edd9))
return -EUCLEAN;
if (ret < 0) {
errno = -ret;
error("failed to commit the initial transaction: %m");
return ret;
}
return generate_new_data_csums_range(fs_info, 0, new_csum_type);
}
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_path path = { 0 };
struct btrfs_key last_key;
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;
ret = btrfs_search_slot(trans, csum_root, &last_key, &path, -1, 1);
nr = btrfs_header_nritems(path.nodes[0]);
/* No item left (empty csum tree), exit. */
if (!nr)
break;
for (start_slot = 0; start_slot < nr; start_slot++) {
struct btrfs_key found_key;
btrfs_item_key_to_cpu(path.nodes[0], &found_key, start_slot);
/* Break from the for loop, we found the first old csum. */
if (found_key.objectid == BTRFS_EXTENT_CSUM_OBJECTID)
break;
}
/* No more old csum item detected, exit. */
if (start_slot == nr)
break;
/* Delete items starting from @start_slot to the end. */
ret = btrfs_del_items(trans, csum_root, &path, start_slot,
nr - start_slot);
if (ret < 0) {
errno = -ret;
error("failed to delete items: %m");
break;
}
btrfs_release_path(&path);
}
btrfs_release_path(&path);
if (ret < 0)
btrfs_abort_transaction(trans, ret);
ret = btrfs_commit_transaction(trans, csum_root);
if (inject_error(0x55fb4d13))
return -EUCLEAN;
if (ret < 0) {
errno = -ret;
error("failed to commit transaction after deleting the old data csums: %m");
}
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 (inject_error(0x2628b3fe))
return -EUCLEAN;
if (ret < 0) {
errno = -ret;
error("failed to commit transaction after changing data csum objectids: %m");
}
return ret;
}
static int rewrite_tree_block_csum(struct btrfs_fs_info *fs_info, u64 logical,
u16 new_csum_type)
{
struct extent_buffer *eb;
u8 result_old[BTRFS_CSUM_SIZE];
u8 result_new[BTRFS_CSUM_SIZE];
int ret;
eb = alloc_dummy_extent_buffer(fs_info, logical, fs_info->nodesize);
if (!eb)
return -ENOMEM;
ret = btrfs_read_extent_buffer(eb, 0, 0, NULL);
if (ret < 0) {
errno = -ret;
error("failed to read tree block at logical %llu: %m", logical);
goto out;
}
/* Verify the csum first. */
btrfs_csum_data(fs_info, fs_info->csum_type, (u8 *)eb->data + BTRFS_CSUM_SIZE,
result_old, fs_info->nodesize - BTRFS_CSUM_SIZE);
btrfs_csum_data(fs_info, new_csum_type, (u8 *)eb->data + BTRFS_CSUM_SIZE,
result_new, fs_info->nodesize - BTRFS_CSUM_SIZE);
/* Matches old csum, rewrite. */
if (memcmp_extent_buffer(eb, result_old, 0, fs_info->csum_size) == 0) {
write_extent_buffer(eb, result_new, 0,
btrfs_csum_type_size(new_csum_type));
ret = write_data_to_disk(fs_info, eb->data, eb->start,
fs_info->nodesize);
if (ret < 0) {
errno = -ret;
error("failed to write tree block at logical %llu: %m",
logical);
}
goto out;
}
/* Already new csum. */
if (memcmp_extent_buffer(eb, result_new, 0, fs_info->csum_size) == 0)
goto out;
/* Csum doesn't match either old or new csum type, bad tree block. */
ret = -EIO;
error("tree block csum mismatch at logical %llu", logical);
out:
free_extent_buffer(eb);
return ret;
}
static int change_meta_csums(struct btrfs_fs_info *fs_info, u16 new_csum_type)
{
struct btrfs_root *extent_root = btrfs_extent_root(fs_info, 0);
struct btrfs_path path = { 0 };
struct btrfs_key key;
u64 super_flags;
int ret;
/* Re-set the super flags, this is for resume cases. */
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 = write_all_supers(fs_info);
if (ret < 0) {
errno = -ret;
error("failed to update super flags: %m");
}
/*
* Disable metadata csum checks first, as we may hit tree blocks with
* either old or new csums.
* We will manually check the meta csums here.
*/
fs_info->skip_csum_check = true;
key.objectid = 0;
key.type = 0;
key.offset = 0;
ret = btrfs_search_slot(NULL, extent_root, &key, &path, 0, 0);
if (ret < 0) {
errno = -ret;
error("failed to get the first tree block of extent tree: %m");
return ret;
}
assert(ret > 0);
while (true) {
btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
if (key.type != BTRFS_EXTENT_ITEM_KEY &&
key.type != BTRFS_METADATA_ITEM_KEY)
goto next;
if (key.type == BTRFS_EXTENT_ITEM_KEY) {
struct btrfs_extent_item *ei;
ei = btrfs_item_ptr(path.nodes[0], path.slots[0],
struct btrfs_extent_item);
if (btrfs_extent_flags(path.nodes[0], ei) &
BTRFS_EXTENT_FLAG_DATA)
goto next;
}
ret = rewrite_tree_block_csum(fs_info, key.objectid, new_csum_type);
if (ret < 0) {
errno = -ret;
error("failed to rewrite csum for tree block %llu: %m",
key.offset);
goto out;
}
next:
ret = btrfs_next_extent_item(extent_root, &path, U64_MAX);
if (ret < 0) {
errno = -ret;
error("failed to get next extent item: %m");
}
if (ret > 0) {
ret = 0;
goto out;
}
}
out:
btrfs_release_path(&path);
/*
* Finish the change by clearing the csum change flag, update the superblock
* csum type, and delete the csum change item in the fs with new csum type.
*/
if (ret == 0) {
struct btrfs_root *tree_root = fs_info->tree_root;
struct btrfs_trans_handle *trans;
u64 super_flags = btrfs_super_flags(fs_info->super_copy);
btrfs_set_super_csum_type(fs_info->super_copy, new_csum_type);
super_flags &= ~(BTRFS_SUPER_FLAG_CHANGING_DATA_CSUM |
BTRFS_SUPER_FLAG_CHANGING_META_CSUM);
btrfs_set_super_flags(fs_info->super_copy, super_flags);
fs_info->csum_type = new_csum_type;
fs_info->csum_size = btrfs_csum_type_size(new_csum_type);
fs_info->skip_csum_check = 0;
trans = btrfs_start_transaction(tree_root, 1);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
errno = -ret;
error("failed to start new transaction with new csum type: %m");
return ret;
}
key.objectid = BTRFS_CSUM_CHANGE_OBJECTID;
key.type = BTRFS_TEMPORARY_ITEM_KEY;
key.offset = new_csum_type;
ret = btrfs_search_slot(trans, tree_root, &key, &path, -1, 1);
if (ret > 0)
ret = -ENOENT;
if (ret < 0) {
errno = -ret;
error("failed to locate the csum change item: %m");
btrfs_release_path(&path);
btrfs_abort_transaction(trans, ret);
return ret;
}
ret = btrfs_del_item(trans, tree_root, &path);
if (ret < 0) {
errno = -ret;
error("failed to delete the csum change item: %m");
btrfs_release_path(&path);
btrfs_abort_transaction(trans, ret);
return ret;
}
btrfs_release_path(&path);
ret = btrfs_commit_transaction(trans, tree_root);
if (inject_error(0x9f0ca518))
return -EUCLEAN;
if (ret < 0) {
errno = -ret;
error("failed to finalize the csum change: %m");
}
}
return ret;
}
/*
* Get the first and last csum items which has @objectid as their objectid.
*
* This would be called to handle data csum resume, which may have both old
* and new csums co-exist in the same csum tree.
*
* Return >0 if there is no such EXTENT_CSUM with given @objectid.
* Return 0 if there is such EXTENT_CSUM and populate @first_ret and @last_ret.
* Return <0 for errors.
*/
static int get_csum_items_range(struct btrfs_fs_info *fs_info,
u64 objectid, u64 *first_ret, u64 *last_ret,
u32 *last_item_size)
{
struct btrfs_root *csum_root = btrfs_csum_root(fs_info, 0);
struct btrfs_path path = { 0 };
struct btrfs_key key;
int ret;
key.objectid = objectid;
key.type = BTRFS_EXTENT_CSUM_KEY;
key.offset = 0;
ret = btrfs_search_slot(NULL, csum_root, &key, &path, 0, 0);
if (ret < 0) {
errno = -ret;
error("failed to search csum tree: %m");
return ret;
}
if (path.slots[0] >= btrfs_header_nritems(path.nodes[0])) {
ret = btrfs_next_leaf(csum_root, &path);
if (ret < 0) {
errno = -ret;
error("failed to search csum tree: %m");
btrfs_release_path(&path);
return ret;
}
/*
* There is no next leaf, meaning we didn't find any csum item
* with given objectid.
*/
if (ret > 0) {
btrfs_release_path(&path);
return ret;
}
}
btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
btrfs_release_path(&path);
if (key.objectid != objectid)
return 1;
*first_ret = key.offset;
key.objectid = objectid;
key.type = BTRFS_EXTENT_CSUM_KEY;
key.offset = (u64)-1;
ret = btrfs_search_slot(NULL, csum_root, &key, &path, 0, 0);
if (ret < 0) {
errno = -ret;
error("failed to search csum tree: %m");
return ret;
}
assert(ret > 0);
ret = btrfs_previous_item(csum_root, &path, objectid,
BTRFS_EXTENT_CSUM_KEY);
if (ret < 0) {
errno = -ret;
error("failed to search csum tree: %m");
btrfs_release_path(&path);
return ret;
}
if (ret > 0) {
btrfs_release_path(&path);
return 1;
}
btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
*last_item_size = btrfs_item_size(path.nodes[0], path.slots[0]);
btrfs_release_path(&path);
*last_ret = key.offset;
return 0;
}
/*
* Verify one data sector to determine which csum type matches the csum.
*
* Return >0 if the current csum type doesn't pass the check (including csum
* item too small compared to csum type).
* Return 0 if the current csum type passes the check.
* Return <0 for other errors.
*/
static int determine_csum_type(struct btrfs_fs_info *fs_info, u64 logical,
u16 csum_type)
{
struct btrfs_root *csum_root = btrfs_csum_root(fs_info, logical);
struct btrfs_path path = { 0 };
struct btrfs_key key;
u16 csum_size = btrfs_csum_type_size(csum_type);
u8 csum_expected[BTRFS_CSUM_SIZE];
void *buf;
int ret;
key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
key.type = BTRFS_EXTENT_CSUM_KEY;
key.offset = logical;
ret = btrfs_search_slot(NULL, csum_root, &key, &path, 0, 0);
if (ret > 0)
ret = -ENOENT;
if (ret < 0) {
errno = -ret;
error("failed to search csum tree: %m");
btrfs_release_path(&path);
return ret;
}
/*
* The csum item size is smaller than expected csum size, no
* more need to check.
*/
if (btrfs_item_size(path.nodes[0], path.slots[0]) < csum_size) {
btrfs_release_path(&path);
return 1;
}
read_extent_buffer(path.nodes[0], csum_expected,
btrfs_item_ptr_offset(path.nodes[0], path.slots[0]),
csum_size);
btrfs_release_path(&path);
buf = malloc(fs_info->sectorsize);
if (!buf)
return -ENOMEM;
ret = read_verify_one_data_sector(fs_info, logical, buf, csum_expected,
csum_type, false);
if (ret < 0)
ret = 1;
free(buf);
return ret;
}
static int resume_data_csum_change(struct btrfs_fs_info *fs_info, u16 new_csum_type)
{
u64 old_csum_first;
u64 old_csum_last;
u64 new_csum_first;
u64 new_csum_last;
bool old_csum_found = false;
bool new_csum_found = false;
u32 old_last_size;
u32 new_last_size;
u64 resume_start;
int ret;
ret = get_csum_items_range(fs_info, BTRFS_EXTENT_CSUM_OBJECTID,
&old_csum_first, &old_csum_last,
&old_last_size);
if (ret < 0)
return ret;
if (ret == 0)
old_csum_found = true;
ret = get_csum_items_range(fs_info, BTRFS_CSUM_CHANGE_OBJECTID,
&new_csum_first, &new_csum_last,
&new_last_size);
if (ret < 0)
return ret;
if (ret == 0)
new_csum_found = true;
/*
* No csum item found at all, this fs has empty csum tree.
* Just go metadata change.
*/
if (!old_csum_found && !new_csum_found)
goto new_meta_csum;
/*
* Only old csums exists. This can be one of the two cases:
* - Only the csum change item inserted, no new csum generated.
* - All data csum is converted to the new type.
*
* Here we need to check if the csum item is in old or new type.
*/
if (old_csum_found && !new_csum_found) {
ret = determine_csum_type(fs_info, old_csum_first, fs_info->csum_type);
if (ret == 0) {
/* All old data csums, restart generation. */
resume_start = 0;
goto new_data_csums;
}
ret = determine_csum_type(fs_info, old_csum_first, new_csum_type);
if (ret == 0) {
/*
* All new data csums, just go metadata csum change, which
* would drop the CHANGING_DATA_CSUM flag for us.
*/
goto new_meta_csum;
}
error("The data checksum for logical %llu doesn't match either old or new csum type, unable to resume",
old_csum_first);
return -EUCLEAN;
}
/*
* Both old and new csum exist, and new csum is only a subset of the
* old ones.
*
* This means we're still generating new data csums.
*/
if (old_csum_found && new_csum_found && old_csum_first <= new_csum_first &&
old_csum_last >= new_csum_last) {
resume_start = new_csum_last + new_last_size /
btrfs_csum_type_size(new_csum_type) *
fs_info->sectorsize;
goto new_data_csums;
}
/*
* Both old and new csum exist, and old csum is a subset of the new ones.
*
* This means we're deleting the old csums.
*/
if (old_csum_found && new_csum_found && new_csum_first <= old_csum_first &&
new_csum_last >= old_csum_last)
goto delete_old;
/*
* Both csums exist but not covering each other, or only new csum exists.
*
* This means we have already deleted all the old csums, is going to or
* have already started objectid change.
*/
if ((old_csum_found && new_csum_found && old_csum_last <= new_csum_first) &&
(!old_csum_found && new_csum_found))
goto change;
/* The remaining cases should not be possible. */
error("unexpected resume condition:");
error("old csum found=%d start=%llu last=%llu new csum found=%d start=%llu last=%llu",
old_csum_found,
old_csum_found ? old_csum_first : 0,
old_csum_found ? old_csum_last : 0,
new_csum_found,
new_csum_found ? new_csum_first : 0,
new_csum_found ? new_csum_last : 0);
return -EUCLEAN;
new_data_csums:
ret = generate_new_data_csums_range(fs_info, resume_start, new_csum_type);
if (ret < 0) {
errno = -ret;
error("failed to generate new data csums: %m");
return ret;
}
delete_old:
ret = delete_old_data_csums(fs_info);
if (ret < 0)
return ret;
change:
ret = change_csum_objectids(fs_info);
if (ret < 0)
return ret;
new_meta_csum:
ret = change_meta_csums(fs_info, new_csum_type);
return ret;
}
static int resume_csum_change(struct btrfs_fs_info *fs_info, u16 new_csum_type)
{
const u64 super_flags = btrfs_super_flags(fs_info->super_copy);
struct btrfs_root *tree_root = fs_info->tree_root;
struct btrfs_path path = { 0 };
struct btrfs_key key;
int ret;
if ((super_flags & (BTRFS_SUPER_FLAG_CHANGING_DATA_CSUM |
BTRFS_SUPER_FLAG_CHANGING_META_CSUM)) ==
(BTRFS_SUPER_FLAG_CHANGING_DATA_CSUM |
BTRFS_SUPER_FLAG_CHANGING_META_CSUM)) {
error(
"invalid super flags, only one bit of CHANGING_DATA_CSUM or CHANGING_META_CSUM can be set");
return -EUCLEAN;
}
key.objectid = BTRFS_CSUM_CHANGE_OBJECTID;
key.type = BTRFS_TEMPORARY_ITEM_KEY;
key.offset = (u64)-1;
ret = btrfs_search_slot(NULL, tree_root, &key, &path, 0, 0);
if (ret < 0) {
errno = -ret;
error("failed to locate the csum change item: %m");
return ret;
}
assert(ret > 0);
ret = btrfs_previous_item(tree_root, &path, BTRFS_CSUM_CHANGE_OBJECTID,
BTRFS_TEMPORARY_ITEM_KEY);
if (ret > 0)
ret = -ENOENT;
if (ret < 0) {
errno = -ret;
error("failed to locate the csum change item: %m");
btrfs_release_path(&path);
return ret;
}
btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
btrfs_release_path(&path);
if (new_csum_type != key.offset) {
ret = -EINVAL;
error(
"target csum type mismatch with interrupted csum type, has %s (%u) expect %s (%llu)",
btrfs_super_csum_name(new_csum_type), new_csum_type,
btrfs_super_csum_name(key.offset), key.offset);
return ret;
}
if (super_flags & BTRFS_SUPER_FLAG_CHANGING_DATA_CSUM) {
ret = resume_data_csum_change(fs_info, new_csum_type);
if (ret < 0) {
errno = -ret;
error("failed to resume data checksum change: %m");
}
return ret;
}
/*
* For metadata resume, just call the same change_meta_csums(), as we
* have no record on previous converted metadata, thus have to go
* through all metadata anyway.
*/
ret = change_meta_csums(fs_info, new_csum_type);
if (ret < 0) {
errno = -ret;
error("failed to resume metadata csum change: %m");
}
return ret;
}
int btrfs_change_csum_type(struct btrfs_fs_info *fs_info, u16 new_csum_type)
{
u16 old_csum_type = fs_info->csum_type;
int ret;
/* Phase 0, check conflicting features. */
ret = check_csum_change_requreiment(fs_info, new_csum_type);
if (ret < 0)
return ret;
if (btrfs_super_flags(fs_info->super_copy) &
(BTRFS_SUPER_FLAG_CHANGING_DATA_CSUM |
BTRFS_SUPER_FLAG_CHANGING_META_CSUM)) {
ret = resume_csum_change(fs_info, new_csum_type);
if (ret < 0) {
errno = -ret;
error("failed to resume unfinished csum change: %m");
return ret;
}
printf("converted csum type from %s (%u) to %s (%u)\n",
btrfs_super_csum_name(old_csum_type), old_csum_type,
btrfs_super_csum_name(new_csum_type), new_csum_type);
return ret;
}
/*
* Phase 1, generate new data csums.
*
* The new data csums would have a different key objectid, and there
* will be a temporary item in root tree to indicate the new checksum
* algo.
*/
ret = generate_new_data_csums(fs_info, new_csum_type);
if (ret < 0) {
errno = -ret;
error("failed to generate new data csums: %m");
return ret;
}
/* Phase 2, delete the old data csums. */
ret = delete_old_data_csums(fs_info);
if (ret < 0)
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.
*
* This has to be done in-place, as we don't have a good method
* like relocation in progs.
* Thus we have to support reading a tree block with either csum.
*/
ret = change_meta_csums(fs_info, new_csum_type);
if (ret == 0)
printf("converted csum type from %s (%u) to %s (%u)\n",
btrfs_super_csum_name(old_csum_type), old_csum_type,
btrfs_super_csum_name(new_csum_type), new_csum_type);
return ret;
}