Added code for calculating crc of erofs blocks (4K size).for now it calculates checksum of first block. but can modified to calculate crc for any no. of blocks
Fill 'feature_compat' field of erofs_super_block so that it can be used on kernel side. . Signed-off-by: Pratik Shinde <[email protected]> --- include/erofs/internal.h | 1 + include/erofs/io.h | 8 ++++++ include/erofs_fs.h | 5 ++-- lib/io.c | 27 ++++++++++++++++++ mkfs/main.c | 71 ++++++++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 110 insertions(+), 2 deletions(-) diff --git a/include/erofs/internal.h b/include/erofs/internal.h index 5384946..53335bc 100644 --- a/include/erofs/internal.h +++ b/include/erofs/internal.h @@ -55,6 +55,7 @@ struct erofs_sb_info { u32 feature_incompat; u64 build_time; u32 build_time_nsec; + u32 feature; }; /* global sbi */ diff --git a/include/erofs/io.h b/include/erofs/io.h index 9775047..e0ca8d9 100644 --- a/include/erofs/io.h +++ b/include/erofs/io.h @@ -19,6 +19,7 @@ int dev_open(const char *devname); void dev_close(void); int dev_write(const void *buf, u64 offset, size_t len); +int dev_read(void *buf, u64 offset, size_t len); int dev_fillzero(u64 offset, size_t len, bool padding); int dev_fsync(void); int dev_resize(erofs_blk_t nblocks); @@ -31,5 +32,12 @@ static inline int blk_write(const void *buf, erofs_blk_t blkaddr, blknr_to_addr(nblocks)); } +static inline int blk_read(void *buf, erofs_blk_t start, + u32 nblocks) +{ + return dev_read(buf, blknr_to_addr(start), + blknr_to_addr(nblocks)); +} + #endif diff --git a/include/erofs_fs.h b/include/erofs_fs.h index f29aa25..9eda6c2 100644 --- a/include/erofs_fs.h +++ b/include/erofs_fs.h @@ -19,6 +19,7 @@ */ #define EROFS_FEATURE_INCOMPAT_LZ4_0PADDING 0x00000001 #define EROFS_ALL_FEATURE_INCOMPAT EROFS_FEATURE_INCOMPAT_LZ4_0PADDING +#define EROFS_FEATURE_SB_CHKSUM 0x0001 /* 128-byte erofs on-disk super block */ struct erofs_super_block { @@ -39,8 +40,8 @@ struct erofs_super_block { __u8 uuid[16]; /* 128-bit uuid for volume */ __u8 volume_name[16]; /* volume name */ __le32 feature_incompat; - - __u8 reserved2[44]; + __le32 chksum_blocks; /* number of blocks used for checksum */ + __u8 reserved2[40]; }; /* diff --git a/lib/io.c b/lib/io.c index 7f5f94d..52f9424 100644 --- a/lib/io.c +++ b/lib/io.c @@ -207,3 +207,30 @@ int dev_resize(unsigned int blocks) return dev_fillzero(st.st_size, length, true); } +int dev_read(void *buf, u64 offset, size_t len) +{ + int ret; + + if (cfg.c_dry_run) + return 0; + + if (!buf) { + erofs_err("buf is NULL"); + return -EINVAL; + } + if (offset >= erofs_devsz || len > erofs_devsz || + offset > erofs_devsz - len) { + erofs_err("read posion[%" PRIu64 ", %zd] is too large beyond" + "the end of device(%" PRIu64 ").", + offset, len, erofs_devsz); + return -EINVAL; + } + + ret = pread64(erofs_devfd, buf, len, (off64_t)offset); + if (ret != (int)len) { + erofs_err("Failed to read data from device - %s:[%" PRIu64 ", %zd].", + erofs_devname, offset, len); + return -errno; + } + return 0; +} diff --git a/mkfs/main.c b/mkfs/main.c index 91a018f..fa793a9 100644 --- a/mkfs/main.c +++ b/mkfs/main.c @@ -22,6 +22,9 @@ #define EROFS_SUPER_END (EROFS_SUPER_OFFSET + sizeof(struct erofs_super_block)) +/* number of blocks for calculating checksum */ +#define EROFS_CKSUM_BLOCKS 1 + static void usage(void) { fprintf(stderr, "usage: [options] FILE DIRECTORY\n\n"); @@ -85,6 +88,10 @@ static int parse_extended_opts(const char *opts) return -EINVAL; cfg.c_force_inodeversion = FORCE_INODE_EXTENDED; } + + if (MATCH_EXTENTED_OPT("nocrc", token, keylen)) { + sbi.feature &= ~EROFS_FEATURE_SB_CHKSUM; + } } return 0; } @@ -180,6 +187,9 @@ int erofs_mkfs_update_super_block(struct erofs_buffer_head *bh, .meta_blkaddr = sbi.meta_blkaddr, .xattr_blkaddr = 0, .feature_incompat = cpu_to_le32(sbi.feature_incompat), + .feature_compat = cpu_to_le32(sb.feature), + .checksum = 0, + .chksum_blocks = cpu_to_le32(EROFS_CKSUM_BLOCKS) }; const unsigned int sb_blksize = round_up(EROFS_SUPER_END, EROFS_BLKSIZ); @@ -202,6 +212,64 @@ int erofs_mkfs_update_super_block(struct erofs_buffer_head *bh, return 0; } +#define CRCPOLY 0x82F63B78 +static inline u32 crc32c(u32 seed, unsigned char const *in, size_t len) +{ + int i; + u32 crc = seed; + + while (len--) { + crc ^= *in++; + for (i = 0; i < 8; i++) { + crc = (crc >> 1) ^ ((crc & 1) ? CRCPOLY : 0); + } + } + return crc; +} + +/* calculate checksum for first n blocks */ +u32 erofs_calc_blk_checksum(erofs_blk_t nblks, u32 *crc) +{ + char *buf; + int err = 0; + + buf = malloc(nblks * EROFS_BLKSIZ); + err = blk_read(buf, 0, nblks); + if (err) { + return err; + } + *crc = crc32c(0, (const unsigned char *)buf, nblks * EROFS_BLKSIZ); + free(buf); + return 0; +} + +void erofs_write_sb_checksum() +{ + struct erofs_super_block *sb; + char buf[EROFS_BLKSIZ]; + int ret = 0; + u32 crc; + + ret = erofs_calc_blk_checksum(EROFS_CKSUM_BLOCKS, &crc); + if (ret) { + return; + } + ret = blk_read(buf, 0, 1); + if (ret) { + return; + } + + sb = (struct erofs_super_block *)((u8 *)buf + EROFS_SUPER_OFFSET); + if (le32_to_cpu(sb->magic) != EROFS_SUPER_MAGIC_V1) { + return; + } + sb->checksum = cpu_to_le32(crc); + ret = blk_write(buf, 0, 1); + if (ret) { + return; + } +} + int main(int argc, char **argv) { int err = 0; @@ -217,6 +285,7 @@ int main(int argc, char **argv) cfg.c_legacy_compress = false; sbi.feature_incompat = EROFS_FEATURE_INCOMPAT_LZ4_0PADDING; + sbi.feature = EROFS_FEATURE_SB_CHKSUM; err = mkfs_parse_options_cfg(argc, argv); if (err) { @@ -301,6 +370,8 @@ int main(int argc, char **argv) err = -EIO; else err = dev_resize(nblocks); + if (sbi.feature & EROFS_FEATURE_SB_CHKSUM) + erofs_write_sb_checksum(); exit: z_erofs_compress_exit(); dev_close(); -- 2.9.3
