1 // SPDX-License-Identifier: GPL-2.0+
3 * BTRFS filesystem implementation for U-Boot
5 * 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
12 #include <linux/compat.h>
15 #define BTRFS_SUPER_FLAG_SUPP (BTRFS_HEADER_FLAG_WRITTEN \
16 | BTRFS_HEADER_FLAG_RELOC \
17 | BTRFS_SUPER_FLAG_ERROR \
18 | BTRFS_SUPER_FLAG_SEEDING \
19 | BTRFS_SUPER_FLAG_METADUMP)
21 #define BTRFS_SUPER_INFO_SIZE 4096
24 * checks if a valid root backup is present.
25 * considers the case when all root backups empty valid.
26 * returns -1 in case of invalid root backup and 0 for valid.
28 static int btrfs_check_super_roots(struct btrfs_super_block *sb)
30 struct btrfs_root_backup *root_backup;
34 for (i = 0; i < BTRFS_NUM_BACKUP_ROOTS; ++i) {
35 root_backup = sb->super_roots + i;
37 if (root_backup->tree_root == 0 && root_backup->tree_root_gen == 0)
40 if (root_backup->tree_root_gen == sb->generation)
44 if (num_empty == BTRFS_NUM_BACKUP_ROOTS) {
46 } else if (newest >= 0) {
53 static inline int is_power_of_2(u64 x)
55 return !(x & (x - 1));
58 static int btrfs_check_super_csum(char *raw_disk_sb)
60 struct btrfs_super_block *disk_sb =
61 (struct btrfs_super_block *) raw_disk_sb;
62 u16 csum_type = le16_to_cpu(disk_sb->csum_type);
64 if (csum_type == BTRFS_CSUM_TYPE_CRC32) {
66 const int csum_size = sizeof(crc);
67 char result[csum_size];
69 crc = btrfs_csum_data(raw_disk_sb + BTRFS_CSUM_SIZE, crc,
70 BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
71 btrfs_csum_final(crc, result);
73 if (memcmp(raw_disk_sb, result, csum_size))
82 static int btrfs_check_super(struct btrfs_super_block *sb)
86 if (sb->flags & ~BTRFS_SUPER_FLAG_SUPP) {
87 printf("%s: Unsupported flags: %llu\n", __func__,
88 sb->flags & ~BTRFS_SUPER_FLAG_SUPP);
91 if (sb->root_level > BTRFS_MAX_LEVEL) {
92 printf("%s: tree_root level too big: %d >= %d\n", __func__,
93 sb->root_level, BTRFS_MAX_LEVEL);
97 if (sb->chunk_root_level > BTRFS_MAX_LEVEL) {
98 printf("%s: chunk_root level too big: %d >= %d\n", __func__,
99 sb->chunk_root_level, BTRFS_MAX_LEVEL);
103 if (sb->log_root_level > BTRFS_MAX_LEVEL) {
104 printf("%s: log_root level too big: %d >= %d\n", __func__,
105 sb->log_root_level, BTRFS_MAX_LEVEL);
109 if (!is_power_of_2(sb->sectorsize) || sb->sectorsize < 4096 ||
110 sb->sectorsize > BTRFS_MAX_METADATA_BLOCKSIZE) {
111 printf("%s: invalid sectorsize %u\n", __func__,
116 if (!is_power_of_2(sb->nodesize) || sb->nodesize < sb->sectorsize ||
117 sb->nodesize > BTRFS_MAX_METADATA_BLOCKSIZE) {
118 printf("%s: invalid nodesize %u\n", __func__, sb->nodesize);
122 if (sb->nodesize != sb->__unused_leafsize) {
123 printf("%s: invalid leafsize %u, should be %u\n", __func__,
124 sb->__unused_leafsize, sb->nodesize);
128 if (!IS_ALIGNED(sb->root, sb->sectorsize)) {
129 printf("%s: tree_root block unaligned: %llu\n", __func__,
134 if (!IS_ALIGNED(sb->chunk_root, sb->sectorsize)) {
135 printf("%s: chunk_root block unaligned: %llu\n", __func__,
140 if (!IS_ALIGNED(sb->log_root, sb->sectorsize)) {
141 printf("%s: log_root block unaligned: %llu\n", __func__,
146 if (memcmp(sb->fsid, sb->dev_item.fsid, BTRFS_UUID_SIZE) != 0) {
147 printf("%s: dev_item UUID does not match fsid\n", __func__);
151 if (sb->bytes_used < 6*sb->nodesize) {
152 printf("%s: bytes_used is too small %llu\n", __func__,
157 if (!is_power_of_2(sb->stripesize)) {
158 printf("%s: invalid stripesize %u\n", __func__, sb->stripesize);
162 if (sb->sys_chunk_array_size > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE) {
163 printf("%s: system chunk array too big %u > %u\n", __func__,
164 sb->sys_chunk_array_size, BTRFS_SYSTEM_CHUNK_ARRAY_SIZE);
168 if (sb->sys_chunk_array_size < sizeof(struct btrfs_key) +
169 sizeof(struct btrfs_chunk)) {
170 printf("%s: system chunk array too small %u < %zu\n", __func__,
171 sb->sys_chunk_array_size, sizeof(struct btrfs_key)
172 + sizeof(struct btrfs_chunk));
179 int btrfs_read_superblock(void)
181 const u64 superblock_offsets[4] = {
187 ALLOC_CACHE_ALIGN_BUFFER(char, raw_sb, BTRFS_SUPER_INFO_SIZE);
188 struct btrfs_super_block *sb = (struct btrfs_super_block *) raw_sb;
192 dev_total_bytes = (u64) btrfs_part_info->size * btrfs_part_info->blksz;
194 btrfs_info.sb.generation = 0;
196 for (i = 0; i < 4; ++i) {
197 if (superblock_offsets[i] + sizeof(sb) > dev_total_bytes)
200 if (!btrfs_devread(superblock_offsets[i], BTRFS_SUPER_INFO_SIZE,
204 if (btrfs_check_super_csum(raw_sb)) {
205 debug("%s: invalid checksum at superblock mirror %i\n",
210 btrfs_super_block_to_cpu(sb);
212 if (sb->magic != BTRFS_MAGIC) {
213 debug("%s: invalid BTRFS magic 0x%016llX at "
214 "superblock mirror %i\n", __func__, sb->magic, i);
215 } else if (sb->bytenr != superblock_offsets[i]) {
216 printf("%s: invalid bytenr 0x%016llX (expected "
217 "0x%016llX) at superblock mirror %i\n",
218 __func__, sb->bytenr, superblock_offsets[i], i);
219 } else if (btrfs_check_super(sb)) {
220 printf("%s: Checking superblock mirror %i failed\n",
222 } else if (sb->generation > btrfs_info.sb.generation) {
223 memcpy(&btrfs_info.sb, sb, sizeof(*sb));
229 if (!btrfs_info.sb.generation) {
230 debug("%s: No valid BTRFS superblock found!\n", __func__);
234 if (btrfs_check_super_roots(&btrfs_info.sb)) {
235 printf("%s: No valid root_backup found!\n", __func__);
239 if (sb->sectorsize != PAGE_SIZE) {
241 "%s: Unsupported sector size (%u), only supports %u as sector size\n",
242 __func__, sb->sectorsize, PAGE_SIZE);
246 if (btrfs_info.sb.num_devices != 1) {
247 printf("%s: Unsupported number of devices (%lli). This driver "
248 "only supports filesystem on one device.\n", __func__,
249 btrfs_info.sb.num_devices);
253 debug("Chosen superblock with generation = %llu\n",
254 btrfs_info.sb.generation);