diff options
Diffstat (limited to 'fs/btrfs/disk-io.c')
| -rw-r--r-- | fs/btrfs/disk-io.c | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 58c32b548e..edebf741fd 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -1,7 +1,12 @@ // 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) @@ -20,3 +25,211 @@ int btrfs_csum_data(u16 csum_type, const u8 *data, u8 *out, size_t len) 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; +} |