Hi Pratik, On Tue, Oct 15, 2019 at 10:48:30AM +0530, Pratik Shinde wrote: > 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 > > 1) Added 'chksum_blocks' field to erofs_super_block > 2) removed unnecessary prints
I think leaving some prints is necessary, but users should know something is wrong when doing checksumming, so these prints should be better with words "checksumming".... > 3) moved EROFS_FEATURE_SB_CHKSUM include/erofs_fs.h > > Signed-off-by: Pratik Shinde <pratikshinde...@gmail.com> > --- > include/erofs/internal.h | 1 + > include/erofs/io.h | 8 ++++++ > include/erofs_fs.h | 3 ++- > lib/io.c | 27 +++++++++++++++++++ > mkfs/main.c | 70 > ++++++++++++++++++++++++++++++++++++++++++++++++ > 5 files changed, 108 insertions(+), 1 deletion(-) > > 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..8bd29d6 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 { > @@ -39,7 +40,7 @@ struct erofs_super_block { > __u8 uuid[16]; /* 128-bit uuid for volume */ > __u8 volume_name[16]; /* volume name */ > __le32 feature_incompat; > - > + __le32 chksum_blocks; /* number of blocks used for checksum */ > __u8 reserved2[44]; reserved2[44] --> reserved2[40]; I think totally this patch is ok, you can resend or I will take this version to experimental branch with small modification tonight... And after the kernel side is ready, we can test properly and merge into mainline. Thanks, Gao Xiang > }; > > 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..0633e83 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 +187,8 @@ 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), > + .checksum = 0, > + .chksum_blocks = cpu_to_le32(EROFS_CKSUM_BLOCKS) > }; > const unsigned int sb_blksize = > round_up(EROFS_SUPER_END, EROFS_BLKSIZ); > @@ -202,6 +211,64 @@ 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 +284,7 @@ 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 +369,8 @@ 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 >