2 * BTRFS filesystem implementation for U-Boot
4 * 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
6 * SPDX-License-Identifier: GPL-2.0+
11 #define BTRFS_SUPER_FLAG_SUPP (BTRFS_HEADER_FLAG_WRITTEN \
12 | BTRFS_HEADER_FLAG_RELOC \
13 | BTRFS_SUPER_FLAG_ERROR \
14 | BTRFS_SUPER_FLAG_SEEDING \
15 | BTRFS_SUPER_FLAG_METADUMP)
17 #define BTRFS_SUPER_INFO_SIZE 4096
19 static int btrfs_newest_root_backup(struct btrfs_super_block *sb)
21 struct btrfs_root_backup *root_backup;
24 for (i = 0; i < BTRFS_NUM_BACKUP_ROOTS; ++i) {
25 root_backup = sb->super_roots + i;
26 if (root_backup->tree_root_gen == sb->generation)
33 static inline int is_power_of_2(u64 x)
35 return !(x & (x - 1));
38 static int btrfs_check_super_csum(char *raw_disk_sb)
40 struct btrfs_super_block *disk_sb =
41 (struct btrfs_super_block *) raw_disk_sb;
42 u16 csum_type = le16_to_cpu(disk_sb->csum_type);
44 if (csum_type == BTRFS_CSUM_TYPE_CRC32) {
46 const int csum_size = sizeof(crc);
47 char result[csum_size];
49 crc = btrfs_csum_data(raw_disk_sb + BTRFS_CSUM_SIZE, crc,
50 BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
51 btrfs_csum_final(crc, result);
53 if (memcmp(raw_disk_sb, result, csum_size))
62 static int btrfs_check_super(struct btrfs_super_block *sb)
66 if (sb->flags & ~BTRFS_SUPER_FLAG_SUPP) {
67 printf("%s: Unsupported flags: %llu\n", __func__,
68 sb->flags & ~BTRFS_SUPER_FLAG_SUPP);
71 if (sb->root_level > BTRFS_MAX_LEVEL) {
72 printf("%s: tree_root level too big: %d >= %d\n", __func__,
73 sb->root_level, BTRFS_MAX_LEVEL);
77 if (sb->chunk_root_level > BTRFS_MAX_LEVEL) {
78 printf("%s: chunk_root level too big: %d >= %d\n", __func__,
79 sb->chunk_root_level, BTRFS_MAX_LEVEL);
83 if (sb->log_root_level > BTRFS_MAX_LEVEL) {
84 printf("%s: log_root level too big: %d >= %d\n", __func__,
85 sb->log_root_level, BTRFS_MAX_LEVEL);
89 if (!is_power_of_2(sb->sectorsize) || sb->sectorsize < 4096 ||
90 sb->sectorsize > BTRFS_MAX_METADATA_BLOCKSIZE) {
91 printf("%s: invalid sectorsize %u\n", __func__,
96 if (!is_power_of_2(sb->nodesize) || sb->nodesize < sb->sectorsize ||
97 sb->nodesize > BTRFS_MAX_METADATA_BLOCKSIZE) {
98 printf("%s: invalid nodesize %u\n", __func__, sb->nodesize);
102 if (sb->nodesize != sb->__unused_leafsize) {
103 printf("%s: invalid leafsize %u, should be %u\n", __func__,
104 sb->__unused_leafsize, sb->nodesize);
108 if (!IS_ALIGNED(sb->root, sb->sectorsize)) {
109 printf("%s: tree_root block unaligned: %llu\n", __func__,
114 if (!IS_ALIGNED(sb->chunk_root, sb->sectorsize)) {
115 printf("%s: chunk_root block unaligned: %llu\n", __func__,
120 if (!IS_ALIGNED(sb->log_root, sb->sectorsize)) {
121 printf("%s: log_root block unaligned: %llu\n", __func__,
126 if (memcmp(sb->fsid, sb->dev_item.fsid, BTRFS_UUID_SIZE) != 0) {
127 printf("%s: dev_item UUID does not match fsid\n", __func__);
131 if (sb->bytes_used < 6*sb->nodesize) {
132 printf("%s: bytes_used is too small %llu\n", __func__,
137 if (!is_power_of_2(sb->stripesize)) {
138 printf("%s: invalid stripesize %u\n", __func__, sb->stripesize);
142 if (sb->sys_chunk_array_size > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE) {
143 printf("%s: system chunk array too big %u > %u\n", __func__,
144 sb->sys_chunk_array_size, BTRFS_SYSTEM_CHUNK_ARRAY_SIZE);
148 if (sb->sys_chunk_array_size < sizeof(struct btrfs_key) +
149 sizeof(struct btrfs_chunk)) {
150 printf("%s: system chunk array too small %u < %zu\n", __func__,
151 sb->sys_chunk_array_size, sizeof(struct btrfs_key)
152 + sizeof(struct btrfs_chunk));
159 int btrfs_read_superblock(void)
161 const u64 superblock_offsets[4] = {
167 char raw_sb[BTRFS_SUPER_INFO_SIZE];
168 struct btrfs_super_block *sb = (struct btrfs_super_block *) raw_sb;
170 int i, root_backup_idx;
172 dev_total_bytes = (u64) btrfs_part_info->size * btrfs_part_info->blksz;
174 btrfs_info.sb.generation = 0;
176 for (i = 0; i < 4; ++i) {
177 if (superblock_offsets[i] + sizeof(sb) > dev_total_bytes)
180 if (!btrfs_devread(superblock_offsets[i], BTRFS_SUPER_INFO_SIZE,
184 if (btrfs_check_super_csum(raw_sb)) {
185 printf("%s: invalid checksum at superblock mirror %i\n",
190 btrfs_super_block_to_cpu(sb);
192 if (sb->magic != BTRFS_MAGIC) {
193 printf("%s: invalid BTRFS magic 0x%016llX at "
194 "superblock mirror %i\n", __func__, sb->magic,
196 } else if (sb->bytenr != superblock_offsets[i]) {
197 printf("%s: invalid bytenr 0x%016llX (expected "
198 "0x%016llX) at superblock mirror %i\n",
199 __func__, sb->bytenr, superblock_offsets[i], i);
200 } else if (btrfs_check_super(sb)) {
201 printf("%s: Checking superblock mirror %i failed\n",
203 } else if (sb->generation > btrfs_info.sb.generation) {
204 memcpy(&btrfs_info.sb, sb, sizeof(*sb));
210 if (!btrfs_info.sb.generation) {
211 printf("%s: No valid BTRFS superblock found!\n", __func__);
215 root_backup_idx = btrfs_newest_root_backup(&btrfs_info.sb);
216 if (root_backup_idx < 0) {
217 printf("%s: No valid root_backup found!\n", __func__);
220 btrfs_info.root_backup = btrfs_info.sb.super_roots + root_backup_idx;
222 if (btrfs_info.root_backup->num_devices != 1) {
223 printf("%s: Unsupported number of devices (%lli). This driver "
224 "only supports filesystem on one device.\n", __func__,
225 btrfs_info.root_backup->num_devices);
229 debug("Chosen superblock with generation = %llu\n",
230 btrfs_info.sb.generation);