btrfs-progs/mkfs/common.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 <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <limits.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <uuid/uuid.h>
#include <blkid/blkid.h>
#include "kernel-shared/ctree.h"
#include "kernel-shared/accessors.h"
#include "kernel-shared/disk-io.h"
#include "kernel-shared/volumes.h"
#include "kernel-shared/transaction.h"
#include "kernel-shared/extent_io.h"
#include "kernel-shared/zoned.h"
#include "common/fsfeatures.h"
#include "common/internal.h"
#include "common/messages.h"
#include "common/path-utils.h"
#include "common/device-utils.h"
#include "common/open-utils.h"
#include "common/string-utils.h"
#include "mkfs/common.h"

static u64 reference_root_table[] = {
	[MKFS_ROOT_TREE]	=	BTRFS_ROOT_TREE_OBJECTID,
	[MKFS_EXTENT_TREE]	=	BTRFS_EXTENT_TREE_OBJECTID,
	[MKFS_CHUNK_TREE]	=	BTRFS_CHUNK_TREE_OBJECTID,
	[MKFS_DEV_TREE]		=	BTRFS_DEV_TREE_OBJECTID,
	[MKFS_FS_TREE]		=	BTRFS_FS_TREE_OBJECTID,
	[MKFS_CSUM_TREE]	=	BTRFS_CSUM_TREE_OBJECTID,
	[MKFS_FREE_SPACE_TREE]	=	BTRFS_FREE_SPACE_TREE_OBJECTID,
	[MKFS_BLOCK_GROUP_TREE]	=	BTRFS_BLOCK_GROUP_TREE_OBJECTID,
};

static int btrfs_write_empty_tree(int fd, struct btrfs_mkfs_config *cfg,
				  struct extent_buffer *buf, u64 objectid,
				  u64 block)
{
	int ret;

	memset(buf->data + sizeof(struct btrfs_header), 0,
	       cfg->nodesize - sizeof(struct btrfs_header));
	btrfs_set_header_bytenr(buf, block);
	btrfs_set_header_owner(buf, objectid);
	btrfs_set_header_nritems(buf, 0);
	csum_tree_block_size(buf, btrfs_csum_type_size(cfg->csum_type), 0,
			     cfg->csum_type);
	ret = btrfs_pwrite(fd, buf->data, cfg->nodesize, block, cfg->zone_size);
	if (ret != cfg->nodesize)
		return ret < 0 ? -errno : -EIO;
	return 0;
}

static int btrfs_create_tree_root(int fd, struct btrfs_mkfs_config *cfg,
				  struct extent_buffer *buf,
				  const enum btrfs_mkfs_block *blocks,
				  int blocks_nr)
{
	struct btrfs_root_item root_item;
	struct btrfs_inode_item *inode_item;
	struct btrfs_disk_key disk_key;
	u32 nritems = 0;
	u32 itemoff;
	int ret = 0;
	int blk;
	int i;
	u8 uuid[BTRFS_UUID_SIZE];
	bool block_group_tree = !!(cfg->features.compat_ro_flags &
				   BTRFS_FEATURE_COMPAT_RO_BLOCK_GROUP_TREE);

	memset(buf->data + sizeof(struct btrfs_header), 0,
		cfg->nodesize - sizeof(struct btrfs_header));
	memset(&root_item, 0, sizeof(root_item));
	memset(&disk_key, 0, sizeof(disk_key));

	/* create the items for the root tree */
	inode_item = &root_item.inode;
	btrfs_set_stack_inode_generation(inode_item, 1);
	btrfs_set_stack_inode_size(inode_item, 3);
	btrfs_set_stack_inode_nlink(inode_item, 1);
	btrfs_set_stack_inode_nbytes(inode_item, cfg->nodesize);
	btrfs_set_stack_inode_mode(inode_item, S_IFDIR | 0755);
	btrfs_set_root_refs(&root_item, 1);
	btrfs_set_root_used(&root_item, cfg->nodesize);
	btrfs_set_root_generation(&root_item, 1);

	btrfs_set_disk_key_type(&disk_key, BTRFS_ROOT_ITEM_KEY);
	btrfs_set_disk_key_offset(&disk_key, 0);
	itemoff = cfg->leaf_data_size - sizeof(root_item);

	for (i = 0; i < blocks_nr; i++) {
		blk = blocks[i];
		if (blk == MKFS_ROOT_TREE || blk == MKFS_CHUNK_TREE)
			continue;

		if (!block_group_tree && blk == MKFS_BLOCK_GROUP_TREE)
			continue;

		btrfs_set_root_bytenr(&root_item, cfg->blocks[blk]);
		btrfs_set_disk_key_objectid(&disk_key,
			reference_root_table[blk]);
		btrfs_set_item_key(buf, &disk_key, nritems);
		btrfs_set_item_offset(buf, nritems, itemoff);
		btrfs_set_item_size(buf, nritems, sizeof(root_item));
		if (blk == MKFS_FS_TREE) {
			time_t now = time(NULL);

			uuid_generate(uuid);
			memcpy(root_item.uuid, uuid, BTRFS_UUID_SIZE);
			btrfs_set_stack_timespec_sec(&root_item.otime, now);
			btrfs_set_stack_timespec_sec(&root_item.ctime, now);
		} else {
			memset(uuid, 0, BTRFS_UUID_SIZE);
			memcpy(root_item.uuid, uuid, BTRFS_UUID_SIZE);
			btrfs_set_stack_timespec_sec(&root_item.otime, 0);
			btrfs_set_stack_timespec_sec(&root_item.ctime, 0);
		}
		write_extent_buffer(buf, &root_item,
			btrfs_item_ptr_offset(buf, nritems),
			sizeof(root_item));
		nritems++;
		itemoff -= sizeof(root_item);
	}

	btrfs_set_header_nritems(buf, nritems);

	/* generate checksum */
	csum_tree_block_size(buf, btrfs_csum_type_size(cfg->csum_type), 0,
			     cfg->csum_type);

	/* write back root tree */
	ret = btrfs_pwrite(fd, buf->data, cfg->nodesize,
			   cfg->blocks[MKFS_ROOT_TREE], cfg->zone_size);
	if (ret != cfg->nodesize)
		return (ret < 0 ? -errno : -EIO);

	return ret;
}

static int create_free_space_tree(int fd, struct btrfs_mkfs_config *cfg,
				  struct extent_buffer *buf, u64 group_start,
				  u64 group_size, u64 free_start)
{
	struct btrfs_free_space_info *info;
	struct btrfs_disk_key disk_key;
	int itemoff = cfg->leaf_data_size;
	int nritems = 0;
	int ret;

	memset(buf->data + sizeof(struct btrfs_header), 0,
	       cfg->nodesize - sizeof(struct btrfs_header));
	itemoff -= sizeof(*info);

	btrfs_set_disk_key_objectid(&disk_key, group_start);
	btrfs_set_disk_key_offset(&disk_key, group_size);
	btrfs_set_disk_key_type(&disk_key, BTRFS_FREE_SPACE_INFO_KEY);
	btrfs_set_item_key(buf, &disk_key, nritems);
	btrfs_set_item_offset(buf, nritems, itemoff);
	btrfs_set_item_size(buf, nritems, sizeof(*info));

	info = btrfs_item_ptr(buf, nritems, struct btrfs_free_space_info);
	btrfs_set_free_space_extent_count(buf, info, 1);
	btrfs_set_free_space_flags(buf, info, 0);

	nritems++;
	btrfs_set_disk_key_objectid(&disk_key, free_start);
	btrfs_set_disk_key_offset(&disk_key, group_start + group_size - free_start);
	btrfs_set_disk_key_type(&disk_key, BTRFS_FREE_SPACE_EXTENT_KEY);
	btrfs_set_item_key(buf, &disk_key, nritems);
	btrfs_set_item_offset(buf, nritems, itemoff);
	btrfs_set_item_size(buf, nritems, 0);

	nritems++;
	btrfs_set_header_bytenr(buf, cfg->blocks[MKFS_FREE_SPACE_TREE]);
	btrfs_set_header_owner(buf, BTRFS_FREE_SPACE_TREE_OBJECTID);
	btrfs_set_header_nritems(buf, nritems);
	csum_tree_block_size(buf, btrfs_csum_type_size(cfg->csum_type), 0,
			     cfg->csum_type);
	ret = btrfs_pwrite(fd, buf->data, cfg->nodesize,
			   cfg->blocks[MKFS_FREE_SPACE_TREE], cfg->zone_size);
	if (ret != cfg->nodesize)
		return ret < 0 ? -errno : -EIO;
	return 0;
}

static void write_block_group_item(struct extent_buffer *buf, u32 nr,
				   u64 objectid, u64 offset, u64 used,
				   u64 chunk_objectid, u32 itemoff)
{
	struct btrfs_block_group_item *bg_item;
	struct btrfs_disk_key disk_key;

	btrfs_set_disk_key_objectid(&disk_key, objectid);
	btrfs_set_disk_key_offset(&disk_key, offset);
	btrfs_set_disk_key_type(&disk_key, BTRFS_BLOCK_GROUP_ITEM_KEY);
	btrfs_set_item_key(buf, &disk_key, nr);
	btrfs_set_item_offset(buf, nr, itemoff);
	btrfs_set_item_size(buf, nr, sizeof(*bg_item));

	bg_item = btrfs_item_ptr(buf, nr, struct btrfs_block_group_item);
	btrfs_set_block_group_used(buf, bg_item, used);
	btrfs_set_block_group_flags(buf, bg_item, BTRFS_BLOCK_GROUP_SYSTEM);
	btrfs_set_block_group_chunk_objectid(buf, bg_item, chunk_objectid);
}

static int create_block_group_tree(int fd, struct btrfs_mkfs_config *cfg,
				   struct extent_buffer *buf,
				   u64 bg_offset, u64 bg_size, u64 bg_used)
{
	int ret;
	u64 chunk_objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;

	/*
	 * For extent-tree-v2, chunk_objectid of block group item is reused
	 * to indicate which extent-tree the block group is in.
	 *
	 * Thus for the initial image, we should set the chunk_objectid to 0,
	 * as all initial bgs are in the extent tree with global id 0.
	 */
	if (cfg->features.incompat_flags & BTRFS_FEATURE_INCOMPAT_EXTENT_TREE_V2)
		chunk_objectid = 0;

	memset(buf->data + sizeof(struct btrfs_header), 0,
		cfg->nodesize - sizeof(struct btrfs_header));
	write_block_group_item(buf, 0, bg_offset, bg_size, bg_used,
			       chunk_objectid, cfg->leaf_data_size -
			       sizeof(struct btrfs_block_group_item));
	btrfs_set_header_bytenr(buf, cfg->blocks[MKFS_BLOCK_GROUP_TREE]);
	btrfs_set_header_owner(buf, BTRFS_BLOCK_GROUP_TREE_OBJECTID);
	btrfs_set_header_nritems(buf, 1);
	csum_tree_block_size(buf, btrfs_csum_type_size(cfg->csum_type), 0,
			     cfg->csum_type);
	ret = btrfs_pwrite(fd, buf->data, cfg->nodesize,
			   cfg->blocks[MKFS_BLOCK_GROUP_TREE], cfg->zone_size);
	if (ret != cfg->nodesize)
		return ret < 0 ? -errno : -EIO;
	return 0;
}

static u64 zoned_system_group_offset(u64 zone_size)
{
	const int zone_shift = ilog2(zone_size);
	u32 zone_num = BTRFS_NR_SB_LOG_ZONES;
	u64 start = (u64)zone_num * zone_size;
	u32 sb_zones[BTRFS_SUPER_MIRROR_MAX];
	int i;

	for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++)
		sb_zones[i] = sb_zone_number(zone_shift, i);

	for (;;) {
		for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
			if (zone_num == sb_zones[i] ||
			    !(btrfs_sb_offset(i) + BTRFS_SUPER_INFO_SIZE <= start ||
			      start + zone_size <= btrfs_sb_offset(i)))
				goto next;
		}

		return start;
next:
		zone_num++;
		start += zone_size;
	}

	__builtin_unreachable();
}

/*
 * Add @block into the @blocks array.
 *
 * The @blocks should already be in ascending order and no duplicate.
 */
static void mkfs_blocks_add(enum btrfs_mkfs_block *blocks, int *blocks_nr,
			    enum btrfs_mkfs_block to_add)
{
	int i;

	for (i = 0; i < *blocks_nr; i++) {
		/* The target is already in the array. */
		if (blocks[i] == to_add)
			return;

		/*
		 * We find the first one past @to_add, move the array one slot
		 * right, insert a new one.
		 */
		if (blocks[i] > to_add) {
			memmove(blocks + i + 1, blocks + i, *blocks_nr - i);
			blocks[i] = to_add;
			(*blocks_nr)++;
			return;
		}
		/* Current one still smaller than @to_add, go to next slot. */
	}
	/* All slots iterated and not match, insert into the last slot. */
	blocks[i] = to_add;
	(*blocks_nr)++;
	return;
}

/*
 * Remove @block from the @blocks array.
 *
 * The @blocks should already be in ascending order and no duplicate.
 */
static void mkfs_blocks_remove(enum btrfs_mkfs_block *blocks, int *blocks_nr,
			       enum btrfs_mkfs_block to_remove)
{
	int i;

	for (i = 0; i < *blocks_nr; i++) {
		/* Found the target, move the array one slot left. */
		if (blocks[i] == to_remove) {
			memmove(blocks + i, blocks + i + 1, *blocks_nr - i - 1);
			(*blocks_nr)--;
		}
	}
	/* Nothing found, exit directly. */
	return;
}

/*
 * @fs_uuid - if NULL, generates a UUID, returns back the new filesystem UUID
 *
 * The superblock signature is not valid, denotes a partially created
 * filesystem, needs to be finalized.
 *
 * The temporary fs will have the following chunk layout:
 * Device extent:
 * 0		1M				5M	......
 * | Reserved	| dev extent for SYS chunk      |
 *
 * And chunk mapping will be:
 * Chunk mapping:
 * 0		1M				5M
 * |		| System chunk, 1:1 mapped	|
 *
 * That's to say, there will only be *ONE* system chunk, mapped to
 * [1M, 5M) physical offset.
 * And the only chunk is also in logical address [1M, 5M), containing
 * all essential tree blocks.
 */
int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
{
	struct btrfs_super_block super;
	struct extent_buffer *buf;
	struct btrfs_disk_key disk_key;
	struct btrfs_extent_item *extent_item;
	struct btrfs_chunk *chunk;
	struct btrfs_dev_item *dev_item;
	struct btrfs_dev_extent *dev_extent;
	enum btrfs_mkfs_block blocks[MKFS_BLOCK_COUNT];
	u8 chunk_tree_uuid[BTRFS_UUID_SIZE];
	u8 *ptr;
	int i;
	int ret;
	int blocks_nr;
	int blk;
	u32 itemoff;
	u32 nritems = 0;
	u64 first_free;
	u64 ref_root;
	u32 array_size;
	u32 item_size;
	u64 total_used = 0;
	int skinny_metadata = !!(cfg->features.incompat_flags &
				 BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA);
	u64 num_bytes;
	u64 system_group_offset = BTRFS_BLOCK_RESERVED_1M_FOR_SUPER;
	u64 system_group_size = BTRFS_MKFS_SYSTEM_GROUP_SIZE;
	bool add_block_group = true;
	bool free_space_tree = !!(cfg->features.compat_ro_flags &
				  BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE);
	bool block_group_tree = !!(cfg->features.compat_ro_flags &
				   BTRFS_FEATURE_COMPAT_RO_BLOCK_GROUP_TREE);
	bool extent_tree_v2 = !!(cfg->features.incompat_flags &
				 BTRFS_FEATURE_INCOMPAT_EXTENT_TREE_V2);

	memcpy(blocks, default_blocks,
	       sizeof(enum btrfs_mkfs_block) * ARRAY_SIZE(default_blocks));
	blocks_nr = ARRAY_SIZE(default_blocks);

	/*
	 * Add one new block for block group tree.
	 * And for block group tree, we don't need to add block group item
	 * into extent tree, the item will be handled in block group tree
	 * initialization.
	 */
	if (block_group_tree) {
		mkfs_blocks_add(blocks, &blocks_nr, MKFS_BLOCK_GROUP_TREE);
		add_block_group = false;
	}

	/* Don't include the free space tree in the blocks to process. */
	if (!free_space_tree)
		mkfs_blocks_remove(blocks, &blocks_nr, MKFS_FREE_SPACE_TREE);

	if ((cfg->features.incompat_flags & BTRFS_FEATURE_INCOMPAT_ZONED)) {
		system_group_offset = zoned_system_group_offset(cfg->zone_size);
		system_group_size = cfg->zone_size;
	}

	buf = malloc(sizeof(*buf) + max(cfg->sectorsize, cfg->nodesize));
	if (!buf)
		return -ENOMEM;

	first_free = BTRFS_SUPER_INFO_OFFSET + cfg->sectorsize * 2 - 1;
	first_free &= ~((u64)cfg->sectorsize - 1);

	memset(&super, 0, sizeof(super));

	num_bytes = (cfg->num_bytes / cfg->sectorsize) * cfg->sectorsize;
	if (!*cfg->fs_uuid) {
		uuid_generate(super.fsid);
		uuid_unparse(super.fsid, cfg->fs_uuid);
	} else {
		uuid_parse(cfg->fs_uuid, super.fsid);
	}
	if (!*cfg->dev_uuid) {
		uuid_generate(super.dev_item.uuid);
		uuid_unparse(super.dev_item.uuid, cfg->dev_uuid);
	} else {
		uuid_parse(cfg->dev_uuid, super.dev_item.uuid);
	}
	uuid_generate(chunk_tree_uuid);

	for (i = 0; i < blocks_nr; i++) {
		blk = blocks[i];
		cfg->blocks[blk] = system_group_offset + cfg->nodesize * i;
		total_used += cfg->nodesize;
	}

	btrfs_set_super_bytenr(&super, BTRFS_SUPER_INFO_OFFSET);
	btrfs_set_super_num_devices(&super, 1);
	btrfs_set_super_magic(&super, BTRFS_MAGIC_TEMPORARY);
	btrfs_set_super_generation(&super, 1);
	btrfs_set_super_root(&super, cfg->blocks[MKFS_ROOT_TREE]);
	btrfs_set_super_chunk_root(&super, cfg->blocks[MKFS_CHUNK_TREE]);
	btrfs_set_super_total_bytes(&super, num_bytes);
	btrfs_set_super_bytes_used(&super, total_used);
	btrfs_set_super_sectorsize(&super, cfg->sectorsize);
	super.__unused_leafsize = cpu_to_le32(cfg->nodesize);
	btrfs_set_super_nodesize(&super, cfg->nodesize);
	btrfs_set_super_stripesize(&super, cfg->stripesize);
	btrfs_set_super_csum_type(&super, cfg->csum_type);
	btrfs_set_super_chunk_root_generation(&super, 1);
	if (cfg->features.incompat_flags & BTRFS_FEATURE_INCOMPAT_ZONED)
		btrfs_set_super_cache_generation(&super, 0);
	else
		btrfs_set_super_cache_generation(&super, -1);
	btrfs_set_super_incompat_flags(&super, cfg->features.incompat_flags);
	if (free_space_tree)
		btrfs_set_super_cache_generation(&super, 0);
	btrfs_set_super_compat_ro_flags(&super, cfg->features.compat_ro_flags);

	if (extent_tree_v2)
		btrfs_set_super_nr_global_roots(&super, 1);

	if (cfg->label)
		strncpy_null(super.label, cfg->label, BTRFS_LABEL_SIZE);

	/* create the tree of root objects */
	memset(buf->data, 0, cfg->nodesize);
	buf->len = cfg->nodesize;
	btrfs_set_header_bytenr(buf, cfg->blocks[MKFS_ROOT_TREE]);
	btrfs_set_header_generation(buf, 1);
	btrfs_set_header_backref_rev(buf, BTRFS_MIXED_BACKREF_REV);
	btrfs_set_header_owner(buf, BTRFS_ROOT_TREE_OBJECTID);
	write_extent_buffer(buf, super.fsid, btrfs_header_fsid(),
			    BTRFS_FSID_SIZE);

	write_extent_buffer(buf, chunk_tree_uuid,
			    btrfs_header_chunk_tree_uuid(buf),
			    BTRFS_UUID_SIZE);

	ret = btrfs_create_tree_root(fd, cfg, buf, blocks, blocks_nr);
	if (ret < 0)
		goto out;

	/* create the items for the extent tree */
	memset(buf->data + sizeof(struct btrfs_header), 0,
		cfg->nodesize - sizeof(struct btrfs_header));
	nritems = 0;
	itemoff = cfg->leaf_data_size;
	for (i = 0; i < blocks_nr; i++) {
		blk = blocks[i];

		/* Add the block group item for our temporary chunk. */
		if (cfg->blocks[blk] > system_group_offset && add_block_group) {
			itemoff -= sizeof(struct btrfs_block_group_item);
			write_block_group_item(buf, nritems,
					       system_group_offset,
					       system_group_size, total_used,
					       BTRFS_FIRST_CHUNK_TREE_OBJECTID,
					       itemoff);
			add_block_group = false;
			nritems++;
		}

		item_size = sizeof(struct btrfs_extent_item);
		if (!skinny_metadata)
			item_size += sizeof(struct btrfs_tree_block_info);

		if (cfg->blocks[blk] < first_free) {
			error("block[%d] below first free: %llu < %llu",
					i, cfg->blocks[blk], first_free);
			ret = -EINVAL;
			goto out;
		}
		if (i > 0 && cfg->blocks[blk] < cfg->blocks[blocks[i - 1]]) {
			error("blocks %d and %d in reverse order: %llu < %llu",
				blk, blocks[i - 1],
				cfg->blocks[blk], cfg->blocks[blocks[i - 1]]);
			ret = -EINVAL;
			goto out;
		}

		/* create extent item */
		itemoff -= item_size;
		btrfs_set_disk_key_objectid(&disk_key, cfg->blocks[blk]);
		if (skinny_metadata) {
			btrfs_set_disk_key_type(&disk_key,
						BTRFS_METADATA_ITEM_KEY);
			btrfs_set_disk_key_offset(&disk_key, 0);
		} else {
			btrfs_set_disk_key_type(&disk_key,
						BTRFS_EXTENT_ITEM_KEY);
			btrfs_set_disk_key_offset(&disk_key, cfg->nodesize);
		}
		btrfs_set_item_key(buf, &disk_key, nritems);
		btrfs_set_item_offset(buf, nritems, itemoff);
		btrfs_set_item_size(buf, nritems, item_size);
		extent_item = btrfs_item_ptr(buf, nritems,
					     struct btrfs_extent_item);
		btrfs_set_extent_refs(buf, extent_item, 1);
		btrfs_set_extent_generation(buf, extent_item, 1);
		btrfs_set_extent_flags(buf, extent_item,
				       BTRFS_EXTENT_FLAG_TREE_BLOCK);
		nritems++;

		/* create extent ref */
		ref_root = reference_root_table[blk];
		btrfs_set_disk_key_objectid(&disk_key, cfg->blocks[blk]);
		btrfs_set_disk_key_offset(&disk_key, ref_root);
		btrfs_set_disk_key_type(&disk_key, BTRFS_TREE_BLOCK_REF_KEY);
		btrfs_set_item_key(buf, &disk_key, nritems);
		btrfs_set_item_offset(buf, nritems, itemoff);
		btrfs_set_item_size(buf, nritems, 0);
		nritems++;
	}
	btrfs_set_header_bytenr(buf, cfg->blocks[MKFS_EXTENT_TREE]);
	btrfs_set_header_owner(buf, BTRFS_EXTENT_TREE_OBJECTID);
	btrfs_set_header_nritems(buf, nritems);
	csum_tree_block_size(buf, btrfs_csum_type_size(cfg->csum_type), 0,
			     cfg->csum_type);
	ret = btrfs_pwrite(fd, buf->data, cfg->nodesize,
			   cfg->blocks[MKFS_EXTENT_TREE], cfg->zone_size);
	if (ret != cfg->nodesize) {
		ret = (ret < 0 ? -errno : -EIO);
		goto out;
	}

	/* create the chunk tree */
	memset(buf->data + sizeof(struct btrfs_header), 0,
		cfg->nodesize - sizeof(struct btrfs_header));
	nritems = 0;
	item_size = sizeof(*dev_item);
	itemoff = cfg->leaf_data_size - item_size;

	/* first device 1 (there is no device 0) */
	btrfs_set_disk_key_objectid(&disk_key, BTRFS_DEV_ITEMS_OBJECTID);
	btrfs_set_disk_key_offset(&disk_key, 1);
	btrfs_set_disk_key_type(&disk_key, BTRFS_DEV_ITEM_KEY);
	btrfs_set_item_key(buf, &disk_key, nritems);
	btrfs_set_item_offset(buf, nritems, itemoff);
	btrfs_set_item_size(buf, nritems, item_size);

	dev_item = btrfs_item_ptr(buf, nritems, struct btrfs_dev_item);
	btrfs_set_device_id(buf, dev_item, 1);
	btrfs_set_device_generation(buf, dev_item, 0);
	btrfs_set_device_total_bytes(buf, dev_item, num_bytes);
	btrfs_set_device_bytes_used(buf, dev_item, system_group_size);
	btrfs_set_device_io_align(buf, dev_item, cfg->sectorsize);
	btrfs_set_device_io_width(buf, dev_item, cfg->sectorsize);
	btrfs_set_device_sector_size(buf, dev_item, cfg->sectorsize);
	btrfs_set_device_type(buf, dev_item, 0);

	write_extent_buffer(buf, super.dev_item.uuid,
			    (unsigned long)btrfs_device_uuid(dev_item),
			    BTRFS_UUID_SIZE);
	write_extent_buffer(buf, super.fsid,
			    (unsigned long)btrfs_device_fsid(dev_item),
			    BTRFS_UUID_SIZE);
	read_extent_buffer(buf, &super.dev_item, (unsigned long)dev_item,
			   sizeof(*dev_item));

	nritems++;
	item_size = btrfs_chunk_item_size(1);
	itemoff = itemoff - item_size;

	/* then we have chunk 0 */
	btrfs_set_disk_key_objectid(&disk_key, BTRFS_FIRST_CHUNK_TREE_OBJECTID);
	btrfs_set_disk_key_offset(&disk_key, system_group_offset);
	btrfs_set_disk_key_type(&disk_key, BTRFS_CHUNK_ITEM_KEY);
	btrfs_set_item_key(buf, &disk_key, nritems);
	btrfs_set_item_offset(buf, nritems, itemoff);
	btrfs_set_item_size(buf, nritems, item_size);

	chunk = btrfs_item_ptr(buf, nritems, struct btrfs_chunk);
	btrfs_set_chunk_length(buf, chunk, system_group_size);
	btrfs_set_chunk_owner(buf, chunk, BTRFS_EXTENT_TREE_OBJECTID);
	btrfs_set_chunk_stripe_len(buf, chunk, BTRFS_STRIPE_LEN);
	btrfs_set_chunk_type(buf, chunk, BTRFS_BLOCK_GROUP_SYSTEM);
	btrfs_set_chunk_io_align(buf, chunk, cfg->sectorsize);
	btrfs_set_chunk_io_width(buf, chunk, cfg->sectorsize);
	btrfs_set_chunk_sector_size(buf, chunk, cfg->sectorsize);
	btrfs_set_chunk_num_stripes(buf, chunk, 1);
	btrfs_set_stripe_devid_nr(buf, chunk, 0, 1);
	btrfs_set_stripe_offset_nr(buf, chunk, 0,
				   system_group_offset);
	nritems++;

	write_extent_buffer(buf, super.dev_item.uuid,
			    (unsigned long)btrfs_stripe_dev_uuid(&chunk->stripe),
			    BTRFS_UUID_SIZE);

	/* copy the key for the chunk to the system array */
	ptr = super.sys_chunk_array;
	array_size = sizeof(disk_key);

	memcpy(ptr, &disk_key, sizeof(disk_key));
	ptr += sizeof(disk_key);

	/* copy the chunk to the system array */
	read_extent_buffer(buf, ptr, (unsigned long)chunk, item_size);
	array_size += item_size;
	ptr += item_size;
	btrfs_set_super_sys_array_size(&super, array_size);

	btrfs_set_header_bytenr(buf, cfg->blocks[MKFS_CHUNK_TREE]);
	btrfs_set_header_owner(buf, BTRFS_CHUNK_TREE_OBJECTID);
	btrfs_set_header_nritems(buf, nritems);
	csum_tree_block_size(buf, btrfs_csum_type_size(cfg->csum_type), 0,
			     cfg->csum_type);
	ret = btrfs_pwrite(fd, buf->data, cfg->nodesize,
			   cfg->blocks[MKFS_CHUNK_TREE], cfg->zone_size);
	if (ret != cfg->nodesize) {
		ret = (ret < 0 ? -errno : -EIO);
		goto out;
	}

	/* create the device tree */
	memset(buf->data + sizeof(struct btrfs_header), 0,
		cfg->nodesize - sizeof(struct btrfs_header));
	nritems = 0;
	itemoff = cfg->leaf_data_size - sizeof(struct btrfs_dev_extent);

	btrfs_set_disk_key_objectid(&disk_key, 1);
	btrfs_set_disk_key_offset(&disk_key, system_group_offset);
	btrfs_set_disk_key_type(&disk_key, BTRFS_DEV_EXTENT_KEY);
	btrfs_set_item_key(buf, &disk_key, nritems);
	btrfs_set_item_offset(buf, nritems, itemoff);
	btrfs_set_item_size(buf, nritems, sizeof(struct btrfs_dev_extent));
	dev_extent = btrfs_item_ptr(buf, nritems, struct btrfs_dev_extent);
	btrfs_set_dev_extent_chunk_tree(buf, dev_extent,
					BTRFS_CHUNK_TREE_OBJECTID);
	btrfs_set_dev_extent_chunk_objectid(buf, dev_extent,
					BTRFS_FIRST_CHUNK_TREE_OBJECTID);
	btrfs_set_dev_extent_chunk_offset(buf, dev_extent,
					  system_group_offset);

	write_extent_buffer(buf, chunk_tree_uuid,
		    (unsigned long)btrfs_dev_extent_chunk_tree_uuid(dev_extent),
		    BTRFS_UUID_SIZE);

	btrfs_set_dev_extent_length(buf, dev_extent, system_group_size);
	nritems++;

	btrfs_set_header_bytenr(buf, cfg->blocks[MKFS_DEV_TREE]);
	btrfs_set_header_owner(buf, BTRFS_DEV_TREE_OBJECTID);
	btrfs_set_header_nritems(buf, nritems);
	csum_tree_block_size(buf, btrfs_csum_type_size(cfg->csum_type), 0,
			     cfg->csum_type);
	ret = btrfs_pwrite(fd, buf->data, cfg->nodesize,
			   cfg->blocks[MKFS_DEV_TREE], cfg->zone_size);
	if (ret != cfg->nodesize) {
		ret = (ret < 0 ? -errno : -EIO);
		goto out;
	}

	/* create the FS root */
	ret = btrfs_write_empty_tree(fd, cfg, buf, BTRFS_FS_TREE_OBJECTID,
				     cfg->blocks[MKFS_FS_TREE]);
	if (ret)
		goto out;
	/* finally create the csum root */
	ret = btrfs_write_empty_tree(fd, cfg, buf, BTRFS_CSUM_TREE_OBJECTID,
				     cfg->blocks[MKFS_CSUM_TREE]);
	if (ret)
		goto out;

	if (free_space_tree) {
		ret = create_free_space_tree(fd, cfg, buf, system_group_offset,
					     system_group_size,
					     system_group_offset + total_used);
		if (ret)
			goto out;
	}

	if (block_group_tree) {
		ret = create_block_group_tree(fd, cfg, buf,
					      system_group_offset,
					      system_group_size, total_used);
		if (ret)
			goto out;
	}

	/* and write out the super block */
	memset(buf->data, 0, BTRFS_SUPER_INFO_SIZE);
	memcpy(buf->data, &super, sizeof(super));
	buf->len = BTRFS_SUPER_INFO_SIZE;
	csum_tree_block_size(buf, btrfs_csum_type_size(cfg->csum_type), 0,
			     cfg->csum_type);
	ret = sbwrite(fd, buf->data, BTRFS_SUPER_INFO_OFFSET);
	if (ret != BTRFS_SUPER_INFO_SIZE) {
		ret = (ret < 0 ? -errno : -EIO);
		goto out;
	}

	ret = fsync(fd);
	if (ret)
		goto out;

	ret = 0;

out:
	free(buf);
	return ret;
}

/*
 * Btrfs minimum size calculation is complicated, it should include at least:
 * 1. system group size
 * 2. minimum global block reserve
 * 3. metadata used at mkfs
 * 4. space reservation to create uuid for first mount.
 * Also, raid factor should also be taken into consideration.
 * To avoid the overkill calculation, (system group + global block rsv) * 2
 * for *EACH* device should be good enough.
 */
static u64 btrfs_min_global_blk_rsv_size(u32 nodesize)
{
	return (u64)nodesize << 10;
}

u64 btrfs_min_dev_size(u32 nodesize, bool mixed, u64 zone_size, u64 meta_profile,
		       u64 data_profile)
{
	u64 reserved = 0;
	u64 meta_size;
	u64 data_size;
	u64 dev_stripes;

	if (zone_size) {
		/* 2 zones for the primary superblock. */
		reserved += 2 * zone_size;

		/*
		 * 1 zone each for the initial SINGLE system, SINGLE metadata,
		 * and SINGLE data block group.
		 */
		reserved += 3 * zone_size;

		/*
		 * On non-SINGLE profile, we need to add real system and
		 * metadata block group. And, we also need to add a space for a
		 * tree-log block group.
		 *
		 * SINGLE profile can reuse the initial block groups and only
		 * need to add a tree-log block group
		 */
		dev_stripes = ((meta_profile & BTRFS_BLOCK_GROUP_DUP) ? 2 : 1);
		if (meta_profile & BTRFS_BLOCK_GROUP_PROFILE_MASK)
			meta_size = 3 * dev_stripes * zone_size;
		else
			meta_size = dev_stripes * zone_size;
		reserved += meta_size;

		/*
		 * On non-SINGLE profile, we need to add real data block group.
		 * And, we also need to add a space for a data relocation block
		 * group.
		 *
		 * SINGLE profile can reuse the initial block groups and only
		 * need to add a data relocation block group.
		 */
		dev_stripes = (data_profile & BTRFS_BLOCK_GROUP_DUP) ? 2 : 1;
		if (data_profile & BTRFS_BLOCK_GROUP_PROFILE_MASK)
			data_size = 2 * dev_stripes * zone_size;
		else
			data_size = dev_stripes * zone_size;
		reserved += data_size;

		return reserved;
	}

	if (mixed)
		return 2 * (BTRFS_MKFS_SYSTEM_GROUP_SIZE +
			    btrfs_min_global_blk_rsv_size(nodesize));

	/*
	 * Minimal size calculation is complex due to several factors:
	 * 0) Reserved 1M range.
	 *
	 * 1) Temporary chunk reuse
	 *    If specified chunk profile is SINGLE, we can reuse
	 *    temporary chunks, no need to allocate new chunks.
	 *
	 * 2) Different minimal chunk size for different profiles:
	 *    For initial sys chunk, chunk size is fixed to 4M.
	 *    For single profile, minimal chunk size is 8M for all.
	 *    For other profiles, minimal chunk and stripe size ranges from 8M
	 *    to 64M.
	 *
	 * To calculate it a little easier, here we assume we don't reuse any
	 * temporary chunk, and calculate the size completely by ourselves.
	 *
	 * Temporary chunks sizes are always fixed:
	 * One initial sys chunk, one SINGLE meta, and one SINGLE data.
	 * The latter two are all 8M, according to @calc_size of
	 * btrfs_alloc_chunk().
	 */
	reserved += BTRFS_BLOCK_RESERVED_1M_FOR_SUPER +
		    BTRFS_MKFS_SYSTEM_GROUP_SIZE + SZ_8M * 2;

	/*
	 * For real chunks, we need to select different sizes:
	 * For SINGLE, it's still fixed to 8M (@calc_size).
	 * For other profiles, refer to max(@min_stripe_size, @calc_size).
	 *
	 * And use the stripe size to calculate its physical used space.
	 */
	dev_stripes = ((meta_profile & BTRFS_BLOCK_GROUP_DUP) ? 2 : 1);
	if (meta_profile & BTRFS_BLOCK_GROUP_PROFILE_MASK)
		meta_size = dev_stripes * (SZ_8M + SZ_32M);
	else
		meta_size = dev_stripes * (SZ_8M + SZ_8M);
	reserved += meta_size;

	dev_stripes = ((data_profile & BTRFS_BLOCK_GROUP_DUP) ? 2 : 1);
	if (data_profile & BTRFS_BLOCK_GROUP_PROFILE_MASK)
		data_size = dev_stripes * SZ_64M;
	else
		data_size = dev_stripes * SZ_8M;
	reserved += data_size;

	return reserved;
}

#define isoctal(c)	(((c) & ~7) == '0')

static inline void translate(char *f, char *t)
{
	while (*f != '\0') {
		if (*f == '\\' &&
		    isoctal(f[1]) && isoctal(f[2]) && isoctal(f[3])) {
			*t++ = 64*(f[1] & 7) + 8*(f[2] & 7) + (f[3] & 7);
			f += 4;
		} else
			*t++ = *f++;
	}
	*t = '\0';
	return;
}

/*
 * Checks if the swap device.
 * Returns 1 if swap device, < 0 on error or 0 if not swap device.
 */
static int is_swap_device(const char *file)
{
	FILE	*f;
	struct stat	st_buf;
	dev_t	dev;
	ino_t	ino = 0;
	char	tmp[PATH_MAX];
	char	buf[PATH_MAX];
	char	*cp;
	int	ret = 0;

	if (stat(file, &st_buf) < 0)
		return -errno;
	if (S_ISBLK(st_buf.st_mode))
		dev = st_buf.st_rdev;
	else if (S_ISREG(st_buf.st_mode)) {
		dev = st_buf.st_dev;
		ino = st_buf.st_ino;
	} else
		return 0;

	if ((f = fopen("/proc/swaps", "r")) == NULL)
		return 0;

	/* skip the first line */
	if (fgets(tmp, sizeof(tmp), f) == NULL)
		goto out;

	while (fgets(tmp, sizeof(tmp), f) != NULL) {
		if ((cp = strchr(tmp, ' ')) != NULL)
			*cp = '\0';
		if ((cp = strchr(tmp, '\t')) != NULL)
			*cp = '\0';
		translate(tmp, buf);
		if (stat(buf, &st_buf) != 0)
			continue;
		if (S_ISBLK(st_buf.st_mode)) {
			if (dev == st_buf.st_rdev) {
				ret = 1;
				break;
			}
		} else if (S_ISREG(st_buf.st_mode)) {
			if (dev == st_buf.st_dev && ino == st_buf.st_ino) {
				ret = 1;
				break;
			}
		}
	}

out:
	fclose(f);

	return ret;
}

/*
 * Check for signature at the offset 0 that would be present in case of zoned
 * device. Workaround for old blkid that do not recognize the format to avoid
 * accidental overwrites.
 */
static int check_btrfs_signature_zoned(const char *device)
{
	int fd;
	int ret;
	struct btrfs_super_block sb;

	fd = open(device, O_RDONLY);
	if (fd < 0)
		return -1;
	ret = pread(fd, &sb, BTRFS_SUPER_INFO_SIZE, 0);
	if (ret < 0) {
		ret = -1;
		goto out;
	}
	if (btrfs_super_magic(&sb) == BTRFS_MAGIC)
		ret = 1;
	else
		ret = 0;
out:
	close(fd);
	return ret;
}

/*
 * Check for existing filesystem or partition table on device.
 * Returns:
 *	 1 for existing fs or partition
 *	 0 for nothing found
 *	-1 for internal error
 */
static int check_overwrite(const char *device)
{
	const char	*type;
	blkid_probe	pr = NULL;
	int		ret;
	blkid_loff_t	size;

	if (!device || !*device)
		return 0;

	ret = -1; /* will reset on success of all setup calls */

	pr = blkid_new_probe_from_filename(device);
	if (!pr)
		goto out;

	size = blkid_probe_get_size(pr);
	if (size < 0)
		goto out;

	/* nothing to overwrite on a 0-length device */
	if (size == 0) {
		ret = 0;
		goto out;
	}

	ret = blkid_probe_enable_partitions(pr, 1);
	if (ret < 0)
		goto out;

	ret = blkid_do_fullprobe(pr);
	if (ret < 0)
		goto out;

	/*
	 * Blkid returns 1 for nothing found and 0 when it finds a signature,
	 * but we want the exact opposite, so reverse the return value here.
	 *
	 * In addition print some useful diagnostics about what actually is
	 * on the device.
	 */
	if (ret) {
		ret = 0;
		goto out;
	}

	if (!blkid_probe_lookup_value(pr, "TYPE", &type, NULL)) {
		error("%s appears to contain an existing filesystem (%s)", device, type);
	} else if (!blkid_probe_lookup_value(pr, "PTTYPE", &type, NULL)) {
		error("%s appears to contain a partition table (%s)", device, type);
	} else {
		error("%s appears to contain something weird according to blkid", device);
	}
	ret = 1;

out:
	if (pr)
		blkid_free_probe(pr);
	if (ret == -1)
		error("probe of %s failed, cannot detect existing filesystem", device);

	/* Either nothing found or there was an error is a reason to double check */
	if (ret == 0 || ret == -1) {
		ret = check_btrfs_signature_zoned(device);
		if (ret > 0) {
			warning(
"%s contains zoned btrfs signature but was not detected by blkid, please update",
				device);
			ret = 1;
		} else if (ret < 0) {
			warning(
			"cannot read superblock on %s, please check manually\n",
				device);
			ret = -1;
		}
	}

	return ret;
}

/*
 * Check if a device is suitable for btrfs
 * returns:
 *  1: something is wrong, an error is printed
 *  0: all is fine
 */
bool test_dev_for_mkfs(const char *file, int force_overwrite)
{
	int ret, fd;
	struct stat st;

	ret = is_swap_device(file);
	if (ret < 0) {
		errno = -ret;
		error("checking status of %s: %m", file);
		return true;
	}
	if (ret == 1) {
		error("%s is a swap device", file);
		return true;
	}
	ret = test_status_for_mkfs(file, force_overwrite);
	if (ret)
		return true;
	/*
	 * Check if the device is busy. Open it in read-only mode to avoid triggering
	 * udev events.
	 */
	fd = open(file, O_RDONLY | O_EXCL);
	if (fd < 0) {
		error("unable to open %s: %m", file);
		return true;
	}
	if (fstat(fd, &st)) {
		error("unable to stat %s: %m", file);
		close(fd);
		return true;
	}
	if (!S_ISBLK(st.st_mode)) {
		error("%s is not a block device", file);
		close(fd);
		return true;
	}
	close(fd);
	return false;
}

/*
 * check if the file (device) is formatted or mounted
 */
bool test_status_for_mkfs(const char *file, bool force_overwrite)
{
	int ret;

	if (!force_overwrite) {
		if (check_overwrite(file)) {
			error("use the -f option to force overwrite of %s",
					file);
			return true;
		}
	}
	ret = check_mounted(file);
	if (ret < 0) {
		errno = -ret;
		if (force_overwrite) {
			warning("forced overwrite but cannot check mount status of %s: %m",
				file);
			return false;
		}
		error("cannot check mount status of %s: %m", file);
		return true;
	}
	if (ret == 1) {
		error("%s is mounted", file);
		return true;
	}

	return false;
}

int is_vol_small(const char *file)
{
	int fd = -1;
	int e;
	struct stat st;
	u64 size;

	fd = open(file, O_RDONLY);
	if (fd < 0)
		return -errno;
	if (fstat(fd, &st) < 0) {
		e = -errno;
		close(fd);
		return e;
	}
	size = device_get_partition_size_fd_stat(fd, &st);
	if (size == 0) {
		close(fd);
		return -1;
	}
	if (size < BTRFS_MKFS_SMALL_VOLUME_SIZE) {
		close(fd);
		return 1;
	} else {
		close(fd);
		return 0;
	}
}

int test_minimum_size(const char *file, u64 min_dev_size)
{
	int fd;
	struct stat statbuf;

	fd = open(file, O_RDONLY);
	if (fd < 0)
		return -errno;
	if (stat(file, &statbuf) < 0) {
		close(fd);
		return -errno;
	}
	if (device_get_partition_size_fd_stat(fd, &statbuf) < min_dev_size) {
		close(fd);
		return 1;
	}
	close(fd);
	return 0;
}