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btrfs-progs: introduce btrfs_make_subvolume() 

There are two different subvolume/data reloc tree creation routines:

- create_subvol() from convert/main.c
  * calls btrfs_copy_root() to create an empty root
    This is not safe, as it relies on the source root to be empty.
  * calls btrfs_read_fs_root() to add it to the cache and trace it
    properly
  * calls btrfs_make_root_dir() to initialize the empty new root

- create_data_reloc_tree() from mkfs/main.c
  * calls btrfs_create_tree() to create an empty root
  * Manually add the root to fs_root cache
    This is only safe for data reloc tree as it's never updated
    inside btrfs-progs.
    But not safe for other subvolume trees.
  * manually setup the root dir

Both have their good and bad aspects, so here we introduce a new helper,
btrfs_make_subvolume():

- Calls btrfs_create_tree() to create an empty root
- Calls btrfs_read_fs_root() to setup the cache and tracking properly
- Calls btrfs_make_root_dir() to initialize the root dir
- Calls btrfs_update_root() to reflect the rootdir change

So this new helper can replace both create_subvol() and
create_data_reloc_tree().

Signed-off-by: Qu Wenruo <wqu@suse.com>
This commit is contained in:
Qu Wenruo 2024-07-02 17:06:25 +09:30 committed by David Sterba
parent 9b74d80919
commit 3c555beabf
8 changed files with 140 additions and 151 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
Makefile
View File

@ -221,6 +221,7 @@ objects = \
common/device-utils.o \
common/extent-cache.o \
common/extent-tree-utils.o \
common/root-tree-utils.o \
common/filesystem-utils.o \
common/format-output.o \
common/fsfeatures.o \

1
check/main.c
View File

@ -59,6 +59,7 @@
#include "common/open-utils.h"
#include "common/string-utils.h"
#include "common/clear-cache.h"
#include "common/root-tree-utils.h"
#include "cmds/commands.h"
#include "mkfs/common.h"
#include "check/common.h"

107
common/root-tree-utils.c Normal file
View File

@ -0,0 +1,107 @@
/*
* 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 <time.h>
#include "common/root-tree-utils.h"
#include "common/messages.h"
#include "kernel-shared/disk-io.h"
int btrfs_make_root_dir(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 objectid)
{
int ret;
struct btrfs_inode_item inode_item;
time_t now = time(NULL);
memset(&inode_item, 0, sizeof(inode_item));
btrfs_set_stack_inode_generation(&inode_item, trans->transid);
btrfs_set_stack_inode_size(&inode_item, 0);
btrfs_set_stack_inode_nlink(&inode_item, 1);
btrfs_set_stack_inode_nbytes(&inode_item, root->fs_info->nodesize);
btrfs_set_stack_inode_mode(&inode_item, S_IFDIR | 0755);
btrfs_set_stack_timespec_sec(&inode_item.atime, now);
btrfs_set_stack_timespec_nsec(&inode_item.atime, 0);
btrfs_set_stack_timespec_sec(&inode_item.ctime, now);
btrfs_set_stack_timespec_nsec(&inode_item.ctime, 0);
btrfs_set_stack_timespec_sec(&inode_item.mtime, now);
btrfs_set_stack_timespec_nsec(&inode_item.mtime, 0);
btrfs_set_stack_timespec_sec(&inode_item.otime, now);
btrfs_set_stack_timespec_nsec(&inode_item.otime, 0);
if (root->fs_info->tree_root == root)
btrfs_set_super_root_dir(root->fs_info->super_copy, objectid);
ret = btrfs_insert_inode(trans, root, objectid, &inode_item);
if (ret)
goto error;
ret = btrfs_insert_inode_ref(trans, root, "..", 2, objectid, objectid, 0);
if (ret)
goto error;
btrfs_set_root_dirid(&root->root_item, objectid);
ret = 0;
error:
return ret;
}
/*
* Create a subvolume and initialize its content with the top inode.
*
* The created tree root would have its root_ref as 1.
* Thus for subvolumes caller needs to properly add ROOT_BACKREF items.
*/
int btrfs_make_subvolume(struct btrfs_trans_handle *trans, u64 objectid)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_root *root;
struct btrfs_key key = {
.objectid = objectid,
.type = BTRFS_ROOT_ITEM_KEY,
};
int ret;
/* FSTREE is different and can not be created by this function. */
UASSERT(objectid != BTRFS_FS_TREE_OBJECTID);
UASSERT(is_fstree(objectid) || objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
root = btrfs_create_tree(trans, &key);
if (IS_ERR(root)) {
ret = PTR_ERR(root);
goto error;
}
/*
* Free it for now, and re-read it from disk to setup cache and
* tracking.
*/
btrfs_free_fs_root(root);
root = btrfs_read_fs_root(fs_info, &key);
if (IS_ERR(root)) {
ret = PTR_ERR(root);
goto error;
}
ret = btrfs_make_root_dir(trans, root, BTRFS_FIRST_FREE_OBJECTID);
if (ret < 0)
goto error;
ret = btrfs_update_root(trans, fs_info->tree_root, &root->root_key,
&root->root_item);
if (ret < 0)
goto error;
return 0;
error:
btrfs_abort_transaction(trans, ret);
return ret;
}

26
common/root-tree-utils.h Normal file
View File

@ -0,0 +1,26 @@
/*
* 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.
*/
#ifndef __ROOT_TREE_UTILS_H__
#define __ROOT_TREE_UTILS_H__
#include "kernel-shared/transaction.h"
int btrfs_make_root_dir(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 objectid);
int btrfs_make_subvolume(struct btrfs_trans_handle *trans, u64 objectid);
#endif

43
convert/main.c
View File

@ -120,6 +120,7 @@
#include "common/box.h"
#include "common/open-utils.h"
#include "common/extent-tree-utils.h"
#include "common/root-tree-utils.h"
#include "common/clear-cache.h"
#include "cmds/commands.h"
#include "check/repair.h"
@ -916,44 +917,6 @@ out:
return ret;
}
static int create_subvol(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 root_objectid)
{
struct extent_buffer *tmp;
struct btrfs_root *new_root;
struct btrfs_key key;
struct btrfs_root_item root_item;
int ret;
ret = btrfs_copy_root(trans, root, root->node, &tmp,
root_objectid);
if (ret)
return ret;
memcpy(&root_item, &root->root_item, sizeof(root_item));
btrfs_set_root_bytenr(&root_item, tmp->start);
btrfs_set_root_level(&root_item, btrfs_header_level(tmp));
btrfs_set_root_generation(&root_item, trans->transid);
free_extent_buffer(tmp);
key.objectid = root_objectid;
key.type = BTRFS_ROOT_ITEM_KEY;
key.offset = trans->transid;
ret = btrfs_insert_root(trans, root->fs_info->tree_root,
&key, &root_item);
key.offset = (u64)-1;
new_root = btrfs_read_fs_root(root->fs_info, &key);
if (!new_root || IS_ERR(new_root)) {
error("unable to fs read root: %lu", PTR_ERR(new_root));
return PTR_ERR(new_root);
}
ret = btrfs_make_root_dir(trans, new_root, BTRFS_FIRST_FREE_OBJECTID);
return ret;
}
/*
* New make_btrfs() has handle system and meta chunks quite well.
* So only need to add remaining data chunks.
@ -1059,13 +1022,13 @@ static int init_btrfs(struct btrfs_mkfs_config *cfg, struct btrfs_root *root,
BTRFS_FIRST_FREE_OBJECTID);
/* subvol for fs image file */
ret = create_subvol(trans, root, CONV_IMAGE_SUBVOL_OBJECTID);
ret = btrfs_make_subvolume(trans, CONV_IMAGE_SUBVOL_OBJECTID);
if (ret < 0) {
error("failed to create subvolume image root: %d", ret);
goto err;
}
/* subvol for data relocation tree */
ret = create_subvol(trans, root, BTRFS_DATA_RELOC_TREE_OBJECTID);
ret = btrfs_make_subvolume(trans, BTRFS_DATA_RELOC_TREE_OBJECTID);
if (ret < 0) {
error("failed to create DATA_RELOC root: %d", ret);
goto err;

39
mkfs/common.c
View File

@ -758,45 +758,6 @@ out:
return ret;
}
int btrfs_make_root_dir(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 objectid)
{
int ret;
struct btrfs_inode_item inode_item;
time_t now = time(NULL);
memset(&inode_item, 0, sizeof(inode_item));
btrfs_set_stack_inode_generation(&inode_item, trans->transid);
btrfs_set_stack_inode_size(&inode_item, 0);
btrfs_set_stack_inode_nlink(&inode_item, 1);
btrfs_set_stack_inode_nbytes(&inode_item, root->fs_info->nodesize);
btrfs_set_stack_inode_mode(&inode_item, S_IFDIR | 0755);
btrfs_set_stack_timespec_sec(&inode_item.atime, now);
btrfs_set_stack_timespec_nsec(&inode_item.atime, 0);
btrfs_set_stack_timespec_sec(&inode_item.ctime, now);
btrfs_set_stack_timespec_nsec(&inode_item.ctime, 0);
btrfs_set_stack_timespec_sec(&inode_item.mtime, now);
btrfs_set_stack_timespec_nsec(&inode_item.mtime, 0);
btrfs_set_stack_timespec_sec(&inode_item.otime, now);
btrfs_set_stack_timespec_nsec(&inode_item.otime, 0);
if (root->fs_info->tree_root == root)
btrfs_set_super_root_dir(root->fs_info->super_copy, objectid);
ret = btrfs_insert_inode(trans, root, objectid, &inode_item);
if (ret)
goto error;
ret = btrfs_insert_inode_ref(trans, root, "..", 2, objectid, objectid, 0);
if (ret)
goto error;
btrfs_set_root_dirid(&root->root_item, objectid);
ret = 0;
error:
return ret;
}
/*
* Btrfs minimum size calculation is complicated, it should include at least:
* 1. system group size

2
mkfs/common.h
View File

@ -103,8 +103,6 @@ struct btrfs_mkfs_config {
};
int make_btrfs(int fd, struct btrfs_mkfs_config *cfg);
int btrfs_make_root_dir(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 objectid);
u64 btrfs_min_dev_size(u32 nodesize, bool mixed, u64 zone_size, u64 meta_profile,
u64 data_profile);
int test_minimum_size(const char *file, u64 min_dev_size);

72
mkfs/main.c
View File

@ -58,6 +58,7 @@
#include "common/units.h"
#include "common/string-utils.h"
#include "common/string-table.h"
#include "common/root-tree-utils.h"
#include "cmds/commands.h"
#include "check/qgroup-verify.h"
#include "mkfs/common.h"
@ -734,75 +735,6 @@ static void update_chunk_allocation(struct btrfs_fs_info *fs_info,
}
}
static int create_data_reloc_tree(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_inode_item *inode;
struct btrfs_root *root;
struct btrfs_path path = { 0 };
struct btrfs_key key = {
.objectid = BTRFS_DATA_RELOC_TREE_OBJECTID,
.type = BTRFS_ROOT_ITEM_KEY,
};
u64 ino = BTRFS_FIRST_FREE_OBJECTID;
char *name = "..";
int ret;
root = btrfs_create_tree(trans, &key);
if (IS_ERR(root)) {
ret = PTR_ERR(root);
goto out;
}
/* Update dirid as created tree has default dirid 0 */
btrfs_set_root_dirid(&root->root_item, ino);
ret = btrfs_update_root(trans, fs_info->tree_root, &root->root_key,
&root->root_item);
if (ret < 0)
goto out;
/* Cache this tree so it can be cleaned up at close_ctree() */
ret = rb_insert(&fs_info->fs_root_tree, &root->rb_node,
btrfs_fs_roots_compare_roots);
if (ret < 0)
goto out;
/* Insert INODE_ITEM */
ret = btrfs_new_inode(trans, root, ino, 0755 | S_IFDIR);
if (ret < 0)
goto out;
/* then INODE_REF */
ret = btrfs_insert_inode_ref(trans, root, name, strlen(name), ino, ino,
0);
if (ret < 0)
goto out;
/* Update nlink of that inode item */
key.objectid = ino;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
ret = btrfs_search_slot(trans, root, &key, &path, 0, 1);
if (ret > 0) {
ret = -ENOENT;
btrfs_release_path(&path);
goto out;
}
if (ret < 0) {
btrfs_release_path(&path);
goto out;
}
inode = btrfs_item_ptr(path.nodes[0], path.slots[0],
struct btrfs_inode_item);
btrfs_set_inode_nlink(path.nodes[0], inode, 1);
btrfs_mark_buffer_dirty(path.nodes[0]);
btrfs_release_path(&path);
return 0;
out:
btrfs_abort_transaction(trans, ret);
return ret;
}
static int btrfs_uuid_tree_add(struct btrfs_trans_handle *trans, u8 *uuid,
u8 type, u64 subvol_id_cpu)
{
@ -1939,7 +1871,7 @@ raid_groups:
goto out;
}
ret = create_data_reloc_tree(trans);
ret = btrfs_make_subvolume(trans, BTRFS_DATA_RELOC_TREE_OBJECTID);
if (ret) {
error("unable to create data reloc tree: %d", ret);
goto out;