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// SPDX-License-Identifier: GPL-2.0+
#include <common.h>
#include <fs_internal.h>
#include <uuid.h>
#include <memalign.h>
#include "kernel-shared/btrfs_tree.h"
#include "disk-io.h"
#include "ctree.h"
#include "btrfs.h"
#include "crypto/hash.h"
int btrfs_csum_data(u16 csum_type, const u8 *data, u8 *out, size_t len)
{
memset(out, 0, BTRFS_CSUM_SIZE);
switch (csum_type) {
case BTRFS_CSUM_TYPE_CRC32:
return hash_crc32c(data, len, out);
case BTRFS_CSUM_TYPE_XXHASH:
return hash_xxhash(data, len, out);
case BTRFS_CSUM_TYPE_SHA256:
return hash_sha256(data, len, out);
default:
printf("Unknown csum type %d\n", csum_type);
return -EINVAL;
}
}
/*
* Check if the super is valid:
* - nodesize/sectorsize - minimum, maximum, alignment
* - tree block starts - alignment
* - number of devices - something sane
* - sys array size - maximum
*/
static int btrfs_check_super(struct btrfs_super_block *sb)
{
u8 result[BTRFS_CSUM_SIZE];
u16 csum_type;
int csum_size;
u8 *metadata_uuid;
if (btrfs_super_magic(sb) != BTRFS_MAGIC)
return -EIO;
csum_type = btrfs_super_csum_type(sb);
if (csum_type >= btrfs_super_num_csums()) {
error("unsupported checksum algorithm %u", csum_type);
return -EIO;
}
csum_size = btrfs_super_csum_size(sb);
btrfs_csum_data(csum_type, (u8 *)sb + BTRFS_CSUM_SIZE,
result, BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
if (memcmp(result, sb->csum, csum_size)) {
error("superblock checksum mismatch");
return -EIO;
}
if (btrfs_super_root_level(sb) >= BTRFS_MAX_LEVEL) {
error("tree_root level too big: %d >= %d",
btrfs_super_root_level(sb), BTRFS_MAX_LEVEL);
goto error_out;
}
if (btrfs_super_chunk_root_level(sb) >= BTRFS_MAX_LEVEL) {
error("chunk_root level too big: %d >= %d",
btrfs_super_chunk_root_level(sb), BTRFS_MAX_LEVEL);
goto error_out;
}
if (btrfs_super_log_root_level(sb) >= BTRFS_MAX_LEVEL) {
error("log_root level too big: %d >= %d",
btrfs_super_log_root_level(sb), BTRFS_MAX_LEVEL);
goto error_out;
}
if (!IS_ALIGNED(btrfs_super_root(sb), 4096)) {
error("tree_root block unaligned: %llu", btrfs_super_root(sb));
goto error_out;
}
if (!IS_ALIGNED(btrfs_super_chunk_root(sb), 4096)) {
error("chunk_root block unaligned: %llu",
btrfs_super_chunk_root(sb));
goto error_out;
}
if (!IS_ALIGNED(btrfs_super_log_root(sb), 4096)) {
error("log_root block unaligned: %llu",
btrfs_super_log_root(sb));
goto error_out;
}
if (btrfs_super_nodesize(sb) < 4096) {
error("nodesize too small: %u < 4096",
btrfs_super_nodesize(sb));
goto error_out;
}
if (!IS_ALIGNED(btrfs_super_nodesize(sb), 4096)) {
error("nodesize unaligned: %u", btrfs_super_nodesize(sb));
goto error_out;
}
if (btrfs_super_sectorsize(sb) < 4096) {
error("sectorsize too small: %u < 4096",
btrfs_super_sectorsize(sb));
goto error_out;
}
if (!IS_ALIGNED(btrfs_super_sectorsize(sb), 4096)) {
error("sectorsize unaligned: %u", btrfs_super_sectorsize(sb));
goto error_out;
}
if (btrfs_super_total_bytes(sb) == 0) {
error("invalid total_bytes 0");
goto error_out;
}
if (btrfs_super_bytes_used(sb) < 6 * btrfs_super_nodesize(sb)) {
error("invalid bytes_used %llu", btrfs_super_bytes_used(sb));
goto error_out;
}
if ((btrfs_super_stripesize(sb) != 4096)
&& (btrfs_super_stripesize(sb) != btrfs_super_sectorsize(sb))) {
error("invalid stripesize %u", btrfs_super_stripesize(sb));
goto error_out;
}
if (btrfs_super_incompat_flags(sb) & BTRFS_FEATURE_INCOMPAT_METADATA_UUID)
metadata_uuid = sb->metadata_uuid;
else
metadata_uuid = sb->fsid;
if (memcmp(metadata_uuid, sb->dev_item.fsid, BTRFS_FSID_SIZE) != 0) {
char fsid[BTRFS_UUID_UNPARSED_SIZE];
char dev_fsid[BTRFS_UUID_UNPARSED_SIZE];
uuid_unparse(sb->metadata_uuid, fsid);
uuid_unparse(sb->dev_item.fsid, dev_fsid);
error("dev_item UUID does not match fsid: %s != %s",
dev_fsid, fsid);
goto error_out;
}
/*
* Hint to catch really bogus numbers, bitflips or so
*/
if (btrfs_super_num_devices(sb) > (1UL << 31)) {
error("suspicious number of devices: %llu",
btrfs_super_num_devices(sb));
}
if (btrfs_super_num_devices(sb) == 0) {
error("number of devices is 0");
goto error_out;
}
/*
* Obvious sys_chunk_array corruptions, it must hold at least one key
* and one chunk
*/
if (btrfs_super_sys_array_size(sb) > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE) {
error("system chunk array too big %u > %u",
btrfs_super_sys_array_size(sb),
BTRFS_SYSTEM_CHUNK_ARRAY_SIZE);
goto error_out;
}
if (btrfs_super_sys_array_size(sb) < sizeof(struct btrfs_disk_key)
+ sizeof(struct btrfs_chunk)) {
error("system chunk array too small %u < %zu",
btrfs_super_sys_array_size(sb),
sizeof(struct btrfs_disk_key) +
sizeof(struct btrfs_chunk));
goto error_out;
}
return 0;
error_out:
error("superblock checksum matches but it has invalid members");
return -EIO;
}
/*
* btrfs_read_dev_super - read a valid primary superblock from a block device
* @desc,@part: file descriptor of the device
* @sb: buffer where the superblock is going to be read in
*
* Unlike the btrfs-progs/kernel version, here we ony care about the first
* super block, thus it's much simpler.
*/
int btrfs_read_dev_super(struct blk_desc *desc, struct disk_partition *part,
struct btrfs_super_block *sb)
{
char tmp[BTRFS_SUPER_INFO_SIZE];
struct btrfs_super_block *buf = (struct btrfs_super_block *)tmp;
int ret;
ret = __btrfs_devread(desc, part, tmp, BTRFS_SUPER_INFO_SIZE,
BTRFS_SUPER_INFO_OFFSET);
if (ret < BTRFS_SUPER_INFO_SIZE)
return -EIO;
if (btrfs_super_bytenr(buf) != BTRFS_SUPER_INFO_OFFSET)
return -EIO;
if (btrfs_check_super(buf))
return -EIO;
memcpy(sb, buf, BTRFS_SUPER_INFO_SIZE);
return 0;
}
int btrfs_read_superblock(void)
{
ALLOC_CACHE_ALIGN_BUFFER(char, raw_sb, BTRFS_SUPER_INFO_SIZE);
struct btrfs_super_block *sb = (struct btrfs_super_block *) raw_sb;
int ret;
btrfs_info.sb.generation = 0;
ret = btrfs_read_dev_super(btrfs_blk_desc, btrfs_part_info, sb);
if (ret < 0) {
pr_debug("%s: No valid BTRFS superblock found!\n", __func__);
return ret;
}
btrfs_super_block_to_cpu(sb);
memcpy(&btrfs_info.sb, sb, sizeof(*sb));
if (btrfs_info.sb.num_devices != 1) {
printf("%s: Unsupported number of devices (%lli). This driver "
"only supports filesystem on one device.\n", __func__,
btrfs_info.sb.num_devices);
return -1;
}
pr_debug("Chosen superblock with generation = %llu\n",
btrfs_info.sb.generation);
return 0;
}
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