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-rw-r--r--fs/btrfs/super.c233
1 files changed, 233 insertions, 0 deletions
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
new file mode 100644
index 0000000000..706286ee2d
--- /dev/null
+++ b/fs/btrfs/super.c
@@ -0,0 +1,233 @@
+/*
+ * BTRFS filesystem implementation for U-Boot
+ *
+ * 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#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 < %u\n", __func__,
+ sb->sys_chunk_array_size, (u32) 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;
+}
generated by cgit (git 2.34.1) at 2024-12-23 05:28:53 +0000