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// SPDX-License-Identifier: GPL-2.0+
/*
* BTRFS filesystem implementation for U-Boot
*
* 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
*/
#include "btrfs.h"
#define BTRFS_SUPER_FLAG_SUPP (BTRFS_HEADER_FLAG_WRITTEN \
| BTRFS_HEADER_FLAG_RELOC \
| BTRFS_SUPER_FLAG_ERROR \
| BTRFS_SUPER_FLAG_SEEDING \
| BTRFS_SUPER_FLAG_METADUMP)
#define BTRFS_SUPER_INFO_SIZE 4096
static int btrfs_newest_root_backup(struct btrfs_super_block *sb)
{
struct btrfs_root_backup *root_backup;
int i, newest = -1;
for (i = 0; i < BTRFS_NUM_BACKUP_ROOTS; ++i) {
root_backup = sb->super_roots + i;
if (root_backup->tree_root_gen == sb->generation)
newest = i;
}
return newest;
}
static inline int is_power_of_2(u64 x)
{
return !(x & (x - 1));
}
static int btrfs_check_super_csum(char *raw_disk_sb)
{
struct btrfs_super_block *disk_sb =
(struct btrfs_super_block *) raw_disk_sb;
u16 csum_type = le16_to_cpu(disk_sb->csum_type);
if (csum_type == BTRFS_CSUM_TYPE_CRC32) {
u32 crc = ~(u32) 0;
const int csum_size = sizeof(crc);
char result[csum_size];
crc = btrfs_csum_data(raw_disk_sb + BTRFS_CSUM_SIZE, crc,
BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
btrfs_csum_final(crc, result);
if (memcmp(raw_disk_sb, result, csum_size))
return -1;
} else {
return -1;
}
return 0;
}
static int btrfs_check_super(struct btrfs_super_block *sb)
{
int ret = 0;
if (sb->flags & ~BTRFS_SUPER_FLAG_SUPP) {
printf("%s: Unsupported flags: %llu\n", __func__,
sb->flags & ~BTRFS_SUPER_FLAG_SUPP);
}
if (sb->root_level > BTRFS_MAX_LEVEL) {
printf("%s: tree_root level too big: %d >= %d\n", __func__,
sb->root_level, BTRFS_MAX_LEVEL);
ret = -1;
}
if (sb->chunk_root_level > BTRFS_MAX_LEVEL) {
printf("%s: chunk_root level too big: %d >= %d\n", __func__,
sb->chunk_root_level, BTRFS_MAX_LEVEL);
ret = -1;
}
if (sb->log_root_level > BTRFS_MAX_LEVEL) {
printf("%s: log_root level too big: %d >= %d\n", __func__,
sb->log_root_level, BTRFS_MAX_LEVEL);
ret = -1;
}
if (!is_power_of_2(sb->sectorsize) || sb->sectorsize < 4096 ||
sb->sectorsize > BTRFS_MAX_METADATA_BLOCKSIZE) {
printf("%s: invalid sectorsize %u\n", __func__,
sb->sectorsize);
ret = -1;
}
if (!is_power_of_2(sb->nodesize) || sb->nodesize < sb->sectorsize ||
sb->nodesize > BTRFS_MAX_METADATA_BLOCKSIZE) {
printf("%s: invalid nodesize %u\n", __func__, sb->nodesize);
ret = -1;
}
if (sb->nodesize != sb->__unused_leafsize) {
printf("%s: invalid leafsize %u, should be %u\n", __func__,
sb->__unused_leafsize, sb->nodesize);
ret = -1;
}
if (!IS_ALIGNED(sb->root, sb->sectorsize)) {
printf("%s: tree_root block unaligned: %llu\n", __func__,
sb->root);
ret = -1;
}
if (!IS_ALIGNED(sb->chunk_root, sb->sectorsize)) {
printf("%s: chunk_root block unaligned: %llu\n", __func__,
sb->chunk_root);
ret = -1;
}
if (!IS_ALIGNED(sb->log_root, sb->sectorsize)) {
printf("%s: log_root block unaligned: %llu\n", __func__,
sb->log_root);
ret = -1;
}
if (memcmp(sb->fsid, sb->dev_item.fsid, BTRFS_UUID_SIZE) != 0) {
printf("%s: dev_item UUID does not match fsid\n", __func__);
ret = -1;
}
if (sb->bytes_used < 6*sb->nodesize) {
printf("%s: bytes_used is too small %llu\n", __func__,
sb->bytes_used);
ret = -1;
}
if (!is_power_of_2(sb->stripesize)) {
printf("%s: invalid stripesize %u\n", __func__, sb->stripesize);
ret = -1;
}
if (sb->sys_chunk_array_size > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE) {
printf("%s: system chunk array too big %u > %u\n", __func__,
sb->sys_chunk_array_size, BTRFS_SYSTEM_CHUNK_ARRAY_SIZE);
ret = -1;
}
if (sb->sys_chunk_array_size < sizeof(struct btrfs_key) +
sizeof(struct btrfs_chunk)) {
printf("%s: system chunk array too small %u < %zu\n", __func__,
sb->sys_chunk_array_size, sizeof(struct btrfs_key)
+ sizeof(struct btrfs_chunk));
ret = -1;
}
return ret;
}
int btrfs_read_superblock(void)
{
const u64 superblock_offsets[4] = {
0x10000ull,
0x4000000ull,
0x4000000000ull,
0x4000000000000ull
};
char raw_sb[BTRFS_SUPER_INFO_SIZE];
struct btrfs_super_block *sb = (struct btrfs_super_block *) raw_sb;
u64 dev_total_bytes;
int i, root_backup_idx;
dev_total_bytes = (u64) btrfs_part_info->size * btrfs_part_info->blksz;
btrfs_info.sb.generation = 0;
for (i = 0; i < 4; ++i) {
if (superblock_offsets[i] + sizeof(sb) > dev_total_bytes)
break;
if (!btrfs_devread(superblock_offsets[i], BTRFS_SUPER_INFO_SIZE,
raw_sb))
break;
if (btrfs_check_super_csum(raw_sb)) {
printf("%s: invalid checksum at superblock mirror %i\n",
__func__, i);
continue;
}
btrfs_super_block_to_cpu(sb);
if (sb->magic != BTRFS_MAGIC) {
printf("%s: invalid BTRFS magic 0x%016llX at "
"superblock mirror %i\n", __func__, sb->magic,
i);
} else if (sb->bytenr != superblock_offsets[i]) {
printf("%s: invalid bytenr 0x%016llX (expected "
"0x%016llX) at superblock mirror %i\n",
__func__, sb->bytenr, superblock_offsets[i], i);
} else if (btrfs_check_super(sb)) {
printf("%s: Checking superblock mirror %i failed\n",
__func__, i);
} else if (sb->generation > btrfs_info.sb.generation) {
memcpy(&btrfs_info.sb, sb, sizeof(*sb));
} else {
/* Nothing */
}
}
if (!btrfs_info.sb.generation) {
printf("%s: No valid BTRFS superblock found!\n", __func__);
return -1;
}
root_backup_idx = btrfs_newest_root_backup(&btrfs_info.sb);
if (root_backup_idx < 0) {
printf("%s: No valid root_backup found!\n", __func__);
return -1;
}
btrfs_info.root_backup = btrfs_info.sb.super_roots + root_backup_idx;
if (btrfs_info.root_backup->num_devices != 1) {
printf("%s: Unsupported number of devices (%lli). This driver "
"only supports filesystem on one device.\n", __func__,
btrfs_info.root_backup->num_devices);
return -1;
}
debug("Chosen superblock with generation = %llu\n",
btrfs_info.sb.generation);
return 0;
}
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