Re: [PATCH v2 08/11] ftrfs: add CRC32 checksumming and Reed-Solomon FEC skeleton

Eric Biggers
2026-04-14T17:34:26Z

On Tue, Apr 14, 2026 at 01:05:49AM +0200, Aurelien DESBRIERES wrote:
> Implement data integrity layer:
>
> - ftrfs_crc32(): CRC32 wrapper via kernel crc32_le(), used for
> per-inode and per-superblock checksums
> - init_gf_tables(): initialize GF(2^8) Galois Field lookup tables
> (primitive polynomial 0x1d) for Reed-Solomon arithmetic
> - gf_mul(): GF(2^8) multiplication via log/exp tables
> - ftrfs_rs_encode(): systematic Reed-Solomon encoder over
> FTRFS_SUBBLOCK_DATA bytes with FTRFS_RS_PARITY check symbols
>
> The RS encoder operates on sub-blocks within each 4096-byte data
> block. Decoding (error correction) is not yet implemented.
>
> Signed-off-by: Aurelien DESBRIERES <aurelien@hackers.camp>

Is there a reason why the kernel's existing Reed-Solomon
encoding/decoding library isn't being used?

- Eric