[dm-devel] Better read bio error granularity?

[Qu Wenruo]

Hi,

Since if any of the split bio got an error, the whole bio will have
bi_status set to some error number.

This is completely fine for write bio, but I'm wondering can we get a
better granularity by introducing per-bvec bi_status or using page status?


One situation is, for fs like btrfs or dm device like dm-verify, if a
large bio is submitted, say a 128K one, and one of the page failed to
pass checksum/hmac verification.

Then the whole 128K will be marked error, while in fact the rest 124K
are completely fine.


Can this be solved by something like per-vec bi_status, or using page
error status to indicate where exactly the error is?

Or is such usage case too niche (only makes sense for read, only makes
sense for fs with verification)?

Thanks,
Qu