[LSF/MM/BPF TOPIC] File system checksum offload

Kanchan Joshi
2025-01-30T09:24:07Z

Hi All,

I would like to propose a discussion on employing checksum offload in
filesystems.
It would be good to co-locate this with the storage track, as the
finer details lie in the block layer and NVMe driver.

For Btrfs, I had a fleeting chat with Joseph during the last LSFMM.
It seemed there will be value in optimizing writes induced by the
separate checksum tree.
Anuj and I have developed an RFC. This may help us have a clearer
discussion and decide the path forward.

https://lore.kernel.org/linux-block/20250129140207.22718-1-joshi.k@samsung.com/

The proposed RFC maintains a generic infrastructure, allowing other
filesystems to adopt it easily.
XFS/Ext4 have native checksumming for metadata but not for data.
With this approach, they could just instruct the SSD to checksum the
data.
But I am unsure if there are FS-specific trade-offs. Maybe that can
also be up for the discussion.