btrfs-progs/tune/convert-bgt.c
Qu Wenruo 68a04bc710 btrfs-progs: tune: add new option to convert back to extent tree
With previous btrfstune support to convert to block-group-tree, it has
implemented most of the infrastructure for bi-directional conversion.

This patch will implement the remaining conversion support to go back to
extent tree.

The modification includes:

- New convert_to_extent_tree() function in btrfstune.c
  It's almost the same as convert_to_bg_tree(), but with small changes:
  * No need to set extra features like NO_HOLES/FST.
  * Need to delete the block group tree when everything finished.

- Update btrfs_delete_and_free_root() to handle non-global roots
  Currently the function can only accepts global roots (extent/csum/free
  space trees)

  If we pass a non-global root into the function, we will screw up
  global_roots_tree and crash.

  Since we're going to use btrfs_delete_and_free_root() to free block
  group tree which is not a global tree, this is needed.

- New handling for half converted fs in get_last_converted_bg()
  There are two cases need to be handled:

  * The bg tree is already empty
    We need to grab the first bg in extent tree.
    Or at conversion function we will fail at grabbing the first bg.

  * The bg tree is not empty
    Then we need to grab the last bg in extent tree.

- Extra root switching in involved functions. This involves:

  * read_converting_block_groups()
  * insert_block_group_item()
  * update_block_group_item()

  We just need to update our target root according to the current
  compat_ro and super flags.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-04-19 01:10:24 +02:00

272 lines
7.4 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 "kernel-shared/ctree.h"
#include "kernel-shared/disk-io.h"
#include "kernel-shared/transaction.h"
#include "common/messages.h"
#include "common/extent-cache.h"
/* After this many block groups we need to commit transaction. */
#define BLOCK_GROUP_BATCH 64
int convert_to_bg_tree(struct btrfs_fs_info *fs_info)
{
struct btrfs_super_block *sb = fs_info->super_copy;
struct btrfs_trans_handle *trans;
struct cache_extent *ce;
int converted_bgs = 0;
int ret;
trans = btrfs_start_transaction(fs_info->tree_root, 2);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
errno = -ret;
error_msg(ERROR_MSG_START_TRANS, "%m");
return ret;
}
/* Set NO_HOLES feature */
btrfs_set_super_incompat_flags(sb, btrfs_super_incompat_flags(sb) |
BTRFS_FEATURE_INCOMPAT_NO_HOLES);
/* We're resuming from previous run. */
if (btrfs_super_flags(sb) & BTRFS_SUPER_FLAG_CHANGING_BG_TREE)
goto iterate_bgs;
ret = btrfs_create_root(trans, fs_info,
BTRFS_BLOCK_GROUP_TREE_OBJECTID);
if (ret < 0) {
error("failed to create block group root: %d", ret);
goto error;
}
btrfs_set_super_flags(sb,
btrfs_super_flags(sb) |
BTRFS_SUPER_FLAG_CHANGING_BG_TREE);
fs_info->last_converted_bg_bytenr = (u64)-1;
/* Now commit the transaction to make above changes to reach disks. */
ret = btrfs_commit_transaction(trans, fs_info->tree_root);
if (ret < 0) {
error_msg(ERROR_MSG_COMMIT_TRANS, "new bg root: %d", ret);
goto error;
}
trans = btrfs_start_transaction(fs_info->tree_root, 2);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
errno = -ret;
error_msg(ERROR_MSG_START_TRANS, "%m");
return ret;
}
iterate_bgs:
if (fs_info->last_converted_bg_bytenr == (u64)-1) {
ce = last_cache_extent(&fs_info->mapping_tree.cache_tree);
} else {
ce = search_cache_extent(&fs_info->mapping_tree.cache_tree,
fs_info->last_converted_bg_bytenr);
if (!ce) {
error("failed to find block group for bytenr %llu",
fs_info->last_converted_bg_bytenr);
ret = -ENOENT;
goto error;
}
ce = prev_cache_extent(ce);
if (!ce) {
error("no more block groups before bytenr %llu",
fs_info->last_converted_bg_bytenr);
ret = -ENOENT;
goto error;
}
}
/* Now convert each block */
while (ce) {
struct cache_extent *prev = prev_cache_extent(ce);
u64 bytenr = ce->start;
ret = btrfs_convert_one_bg(trans, bytenr);
if (ret < 0)
goto error;
converted_bgs++;
ce = prev;
if (converted_bgs % BLOCK_GROUP_BATCH == 0) {
ret = btrfs_commit_transaction(trans,
fs_info->tree_root);
if (ret < 0) {
errno = -ret;
error_msg(ERROR_MSG_COMMIT_TRANS, "%m");
return ret;
}
trans = btrfs_start_transaction(fs_info->tree_root, 2);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
errno = -ret;
error_msg(ERROR_MSG_START_TRANS, "%m");
return ret;
}
}
}
/*
* All bgs converted, remove the CHANGING_BG flag and set the compat ro
* flag.
*/
fs_info->last_converted_bg_bytenr = 0;
btrfs_set_super_flags(sb,
btrfs_super_flags(sb) &
~BTRFS_SUPER_FLAG_CHANGING_BG_TREE);
btrfs_set_super_compat_ro_flags(sb,
btrfs_super_compat_ro_flags(sb) |
BTRFS_FEATURE_COMPAT_RO_BLOCK_GROUP_TREE);
ret = btrfs_commit_transaction(trans, fs_info->tree_root);
if (ret < 0) {
errno = -ret;
error_msg(ERROR_MSG_COMMIT_TRANS, "final transaction: %m");
return ret;
}
pr_verbose(LOG_DEFAULT, "Converted the filesystem to block group tree feature\n");
return 0;
error:
btrfs_abort_transaction(trans, ret);
return ret;
}
int convert_to_extent_tree(struct btrfs_fs_info *fs_info)
{
struct btrfs_super_block *sb = fs_info->super_copy;
struct btrfs_trans_handle *trans;
struct cache_extent *ce;
u32 converted_bgs = 0;
int ret;
trans = btrfs_start_transaction(fs_info->tree_root, 2);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
error_msg(ERROR_MSG_START_TRANS, "%m");
return ret;
}
/* We're resuming from previous run. */
if (btrfs_super_flags(sb) & BTRFS_SUPER_FLAG_CHANGING_BG_TREE)
goto iterate_bgs;
btrfs_set_super_flags(sb, btrfs_super_flags(sb) | BTRFS_SUPER_FLAG_CHANGING_BG_TREE);
fs_info->last_converted_bg_bytenr = (u64)-1;
/* Now commit the transaction to make the above changes to reach disks. */
ret = btrfs_commit_transaction(trans, fs_info->tree_root);
if (ret < 0) {
errno = -ret;
error_msg(ERROR_MSG_COMMIT_TRANS, "new extent tree root: %m");
goto error;
}
trans = btrfs_start_transaction(fs_info->tree_root, 2);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
errno = -ret;
error_msg(ERROR_MSG_START_TRANS, "%m");
return ret;
}
iterate_bgs:
if (fs_info->last_converted_bg_bytenr == (u64)-1) {
ce = last_cache_extent(&fs_info->mapping_tree.cache_tree);
} else {
ce = search_cache_extent(&fs_info->mapping_tree.cache_tree,
fs_info->last_converted_bg_bytenr);
if (!ce) {
error("failed to find block group for bytenr %llu",
fs_info->last_converted_bg_bytenr);
ret = -ENOENT;
goto error;
}
ce = prev_cache_extent(ce);
if (!ce) {
error("no more block groups before bytenr %llu",
fs_info->last_converted_bg_bytenr);
ret = -ENOENT;
goto error;
}
}
/* Now convert each block group. */
while (ce) {
struct cache_extent *prev = prev_cache_extent(ce);
u64 bytenr = ce->start;
ret = btrfs_convert_one_bg(trans, bytenr);
if (ret < 0)
goto error;
converted_bgs++;
ce = prev;
if (converted_bgs % BLOCK_GROUP_BATCH == 0) {
ret = btrfs_commit_transaction(trans, fs_info->tree_root);
if (ret < 0) {
errno = -ret;
error_msg(ERROR_MSG_COMMIT_TRANS, "%m");
return ret;
}
trans = btrfs_start_transaction(fs_info->tree_root, 2);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
errno = -ret;
error_msg(ERROR_MSG_COMMIT_TRANS, "%m");
return ret;
}
}
}
/*
* Remove block group tree, at this stage, the block group tree root
* should be empty.
*/
ASSERT(btrfs_header_nritems(fs_info->block_group_root->node) == 0);
ret = btrfs_delete_and_free_root(trans, fs_info->block_group_root);
if (ret < 0) {
errno = -ret;
error("failed to remove bg tree: %m");
goto error;
}
fs_info->block_group_root = NULL;
/*
* All bgs converted and bg tree removed, remove the CHANGING_BG_TREE
* flag and remove the compat ro flag.
*/
fs_info->last_converted_bg_bytenr = 0;
btrfs_set_super_flags(sb,
btrfs_super_flags(sb) & ~BTRFS_SUPER_FLAG_CHANGING_BG_TREE);
btrfs_set_super_compat_ro_flags(sb,
btrfs_super_compat_ro_flags(sb) &
~BTRFS_FEATURE_COMPAT_RO_BLOCK_GROUP_TREE);
ret = btrfs_commit_transaction(trans, fs_info->tree_root);
if (ret < 0) {
errno = -ret;
error_msg(ERROR_MSG_COMMIT_TRANS, "%m");
return ret;
}
pr_verbose(LOG_DEFAULT,
"Converted filesystem with block-group-tree to extent tree feature");
return 0;
error:
btrfs_abort_transaction(trans, ret);
return ret;
}