| Huang Jianan | 024fb2f | 2022-02-26 15:05:47 +0800 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0+ |
| 2 | #include "internal.h" |
| 3 | |
| 4 | static bool check_layout_compatibility(struct erofs_sb_info *sbi, |
| 5 | struct erofs_super_block *dsb) |
| 6 | { |
| 7 | const unsigned int feature = le32_to_cpu(dsb->feature_incompat); |
| 8 | |
| 9 | sbi->feature_incompat = feature; |
| 10 | |
| 11 | /* check if current kernel meets all mandatory requirements */ |
| 12 | if (feature & (~EROFS_ALL_FEATURE_INCOMPAT)) { |
| 13 | erofs_err("unidentified incompatible feature %x, please upgrade kernel version", |
| 14 | feature & ~EROFS_ALL_FEATURE_INCOMPAT); |
| 15 | return false; |
| 16 | } |
| 17 | return true; |
| 18 | } |
| 19 | |
| 20 | static int erofs_init_devices(struct erofs_sb_info *sbi, |
| 21 | struct erofs_super_block *dsb) |
| 22 | { |
| 23 | unsigned int ondisk_extradevs, i; |
| 24 | erofs_off_t pos; |
| 25 | |
| 26 | sbi->total_blocks = sbi->primarydevice_blocks; |
| 27 | |
| 28 | if (!erofs_sb_has_device_table()) |
| 29 | ondisk_extradevs = 0; |
| 30 | else |
| 31 | ondisk_extradevs = le16_to_cpu(dsb->extra_devices); |
| 32 | |
| 33 | if (ondisk_extradevs != sbi->extra_devices) { |
| 34 | erofs_err("extra devices don't match (ondisk %u, given %u)", |
| 35 | ondisk_extradevs, sbi->extra_devices); |
| 36 | return -EINVAL; |
| 37 | } |
| 38 | if (!ondisk_extradevs) |
| 39 | return 0; |
| 40 | |
| 41 | sbi->device_id_mask = roundup_pow_of_two(ondisk_extradevs + 1) - 1; |
| 42 | sbi->devs = calloc(ondisk_extradevs, sizeof(*sbi->devs)); |
| 43 | pos = le16_to_cpu(dsb->devt_slotoff) * EROFS_DEVT_SLOT_SIZE; |
| 44 | for (i = 0; i < ondisk_extradevs; ++i) { |
| 45 | struct erofs_deviceslot dis; |
| 46 | int ret; |
| 47 | |
| 48 | ret = erofs_dev_read(0, &dis, pos, sizeof(dis)); |
| 49 | if (ret < 0) |
| 50 | return ret; |
| 51 | |
| 52 | sbi->devs[i].mapped_blkaddr = dis.mapped_blkaddr; |
| 53 | sbi->total_blocks += dis.blocks; |
| 54 | pos += EROFS_DEVT_SLOT_SIZE; |
| 55 | } |
| 56 | return 0; |
| 57 | } |
| 58 | |
| 59 | int erofs_read_superblock(void) |
| 60 | { |
| 61 | char data[EROFS_BLKSIZ]; |
| 62 | struct erofs_super_block *dsb; |
| 63 | unsigned int blkszbits; |
| 64 | int ret; |
| 65 | |
| 66 | ret = erofs_blk_read(data, 0, 1); |
| 67 | if (ret < 0) { |
| 68 | erofs_err("cannot read erofs superblock: %d", ret); |
| 69 | return -EIO; |
| 70 | } |
| 71 | dsb = (struct erofs_super_block *)(data + EROFS_SUPER_OFFSET); |
| 72 | |
| 73 | ret = -EINVAL; |
| 74 | if (le32_to_cpu(dsb->magic) != EROFS_SUPER_MAGIC_V1) { |
| 75 | erofs_err("cannot find valid erofs superblock"); |
| 76 | return ret; |
| 77 | } |
| 78 | |
| 79 | sbi.feature_compat = le32_to_cpu(dsb->feature_compat); |
| 80 | |
| 81 | blkszbits = dsb->blkszbits; |
| 82 | /* 9(512 bytes) + LOG_SECTORS_PER_BLOCK == LOG_BLOCK_SIZE */ |
| 83 | if (blkszbits != LOG_BLOCK_SIZE) { |
| 84 | erofs_err("blksize %u isn't supported on this platform", |
| 85 | 1 << blkszbits); |
| 86 | return ret; |
| 87 | } |
| 88 | |
| 89 | if (!check_layout_compatibility(&sbi, dsb)) |
| 90 | return ret; |
| 91 | |
| 92 | sbi.primarydevice_blocks = le32_to_cpu(dsb->blocks); |
| 93 | sbi.meta_blkaddr = le32_to_cpu(dsb->meta_blkaddr); |
| 94 | sbi.xattr_blkaddr = le32_to_cpu(dsb->xattr_blkaddr); |
| 95 | sbi.islotbits = EROFS_ISLOTBITS; |
| 96 | sbi.root_nid = le16_to_cpu(dsb->root_nid); |
| 97 | sbi.inos = le64_to_cpu(dsb->inos); |
| 98 | sbi.checksum = le32_to_cpu(dsb->checksum); |
| 99 | |
| 100 | sbi.build_time = le64_to_cpu(dsb->build_time); |
| 101 | sbi.build_time_nsec = le32_to_cpu(dsb->build_time_nsec); |
| 102 | |
| 103 | memcpy(&sbi.uuid, dsb->uuid, sizeof(dsb->uuid)); |
| 104 | return erofs_init_devices(&sbi, dsb); |
| 105 | } |