On 2019/10/28 22:23, Gao Xiang wrote: > From: Pratik Shinde <[email protected]> > > Added code for calculating crc of erofs blocks (4K size). > For now it calculates checksum of first block. but it can > be modified to calculate crc for any no. of blocks. > > Note that the first 1024 bytes are not checksumed to allow > for the installation of x86 boot sectors and other oddities. > > Fill 'feature_compat' field of erofs_super_block so that it > can be used on kernel side. also fixing one typo. > > Signed-off-by: Pratik Shinde <[email protected]> > Signed-off-by: Gao Xiang <[email protected]> > --- > > changes since v7: > - get rid of `chksum_blocks' pointed out by Chao. > > > include/erofs/internal.h | 1 + > include/erofs/io.h | 8 +++++ > include/erofs_fs.h | 3 +- > lib/io.c | 27 ++++++++++++++++ > mkfs/main.c | 68 ++++++++++++++++++++++++++++++++++++++++ > 5 files changed, 106 insertions(+), 1 deletion(-) > > diff --git a/include/erofs/internal.h b/include/erofs/internal.h > index 25ce7b54442d..9e2bb9ce33b6 100644 > --- a/include/erofs/internal.h > +++ b/include/erofs/internal.h > @@ -52,6 +52,7 @@ struct erofs_sb_info { > erofs_blk_t meta_blkaddr; > erofs_blk_t xattr_blkaddr; > > + u32 feature_compat; > u32 feature_incompat; > u64 build_time; > u32 build_time_nsec; > diff --git a/include/erofs/io.h b/include/erofs/io.h > index 97750478b5ab..e0ca8d949130 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 f29aa2516a99..bcc4f0c630ad 100644 > --- a/include/erofs_fs.h > +++ b/include/erofs_fs.h > @@ -13,6 +13,8 @@ > #define EROFS_SUPER_MAGIC_V1 0xE0F5E1E2 > #define EROFS_SUPER_OFFSET 1024 > > +#define EROFS_FEATURE_COMPAT_SB_CHKSUM 0x00000001 > + > /* > * Any bits that aren't in EROFS_ALL_FEATURE_INCOMPAT should > * be incompatible with this kernel version. > @@ -39,7 +41,6 @@ struct erofs_super_block { > __u8 uuid[16]; /* 128-bit uuid for volume */ > __u8 volume_name[16]; /* volume name */ > __le32 feature_incompat; > - > __u8 reserved2[44]; > }; > > diff --git a/lib/io.c b/lib/io.c > index 7f5f94dd6b1e..52f9424d201b 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;
Minor thing, I notice caller wrap this errno to EIO, so we'd better print errno here or by caller? Other part looks good to me anyway. Reviewed-by: Chao Yu <[email protected]> Thanks, > + } > + return 0; > +} > diff --git a/mkfs/main.c b/mkfs/main.c > index ab57896e9ca8..eeb6ccc55b82 100644 > --- a/mkfs/main.c > +++ b/mkfs/main.c > @@ -109,6 +109,12 @@ static int parse_extended_opts(const char *opts) > return -EINVAL; > cfg.c_force_inodeversion = FORCE_INODE_EXTENDED; > } > + > + if (MATCH_EXTENTED_OPT("nosbcrc", token, keylen)) { > + if (vallen) > + return -EINVAL; > + sbi.feature_compat &= ~EROFS_FEATURE_COMPAT_SB_CHKSUM; > + } > } > return 0; > } > @@ -218,6 +224,8 @@ int erofs_mkfs_update_super_block(struct > erofs_buffer_head *bh, > .meta_blkaddr = sbi.meta_blkaddr, > .xattr_blkaddr = sbi.xattr_blkaddr, > .feature_incompat = cpu_to_le32(sbi.feature_incompat), > + .feature_compat = cpu_to_le32(sbi.feature_compat & > + ~EROFS_FEATURE_COMPAT_SB_CHKSUM), > }; > const unsigned int sb_blksize = > round_up(EROFS_SUPER_END, EROFS_BLKSIZ); > @@ -240,6 +248,62 @@ int erofs_mkfs_update_super_block(struct > erofs_buffer_head *bh, > return 0; > } > > +#define CRC32C_POLY_LE 0x82F63B78 > +static inline u32 crc32c(u32 crc, const u8 *in, size_t len) > +{ > + int i; > + > + while (len--) { > + crc ^= *in++; > + for (i = 0; i < 8; i++) > + crc = (crc >> 1) ^ ((crc & 1) ? CRC32C_POLY_LE : 0); > + } > + return crc; > +} > + > +static int erofs_superblock_csum_set(void) > +{ > + int ret; > + u8 buf[EROFS_BLKSIZ]; > + u32 crc; > + struct erofs_super_block *sb; > + > + ret = blk_read(buf, 0, 1); > + if (ret) { > + erofs_err("failed to read superblock to fill checksum"); > + return -EIO; > + } > + > + /* > + * skip the first 1024 bytes, to allow for the installation > + * of x86 boot sectors and other oddities. > + */ > + sb = (struct erofs_super_block *)(buf + EROFS_SUPER_OFFSET); > + > + if (le32_to_cpu(sb->magic) != EROFS_SUPER_MAGIC_V1) { > + erofs_err("internal error: not an erofs valid image"); > + return -EFAULT; > + } > + > + /* turn on checksum feature */ > + sb->feature_compat = cpu_to_le32(le32_to_cpu(sb->feature_compat) | > + EROFS_FEATURE_COMPAT_SB_CHKSUM); > + crc = crc32c(~0, (u8 *)sb, EROFS_BLKSIZ - EROFS_SUPER_OFFSET); > + > + /* set up checksum field to erofs_super_block */ > + sb->checksum = cpu_to_le32(crc); > + > + ret = blk_write(buf, 0, 1); > + if (ret) { > + erofs_err("failed to write checksumed superblock: %s", > + erofs_strerror(ret)); > + return ret; > + } > + > + erofs_info("superblock checksum 0x%08x written", crc); > + return 0; > +} > + > int main(int argc, char **argv) > { > int err = 0; > @@ -255,6 +319,7 @@ int main(int argc, char **argv) > > cfg.c_legacy_compress = false; > sbi.feature_incompat = EROFS_FEATURE_INCOMPAT_LZ4_0PADDING; > + sbi.feature_compat = EROFS_FEATURE_COMPAT_SB_CHKSUM; > > err = mkfs_parse_options_cfg(argc, argv); > if (err) { > @@ -337,6 +402,9 @@ int main(int argc, char **argv) > err = -EIO; > else > err = dev_resize(nblocks); > + > + if (!err && (sbi.feature_compat & EROFS_FEATURE_COMPAT_SB_CHKSUM)) > + err = erofs_superblock_csum_set(); > exit: > z_erofs_compress_exit(); > dev_close(); >
