On Wed, Jun 05, 2024 at 08:05:20PM +0530, Kanchan Joshi wrote: > On Wed, Jun 5, 2024 at 12:01???PM Christoph Hellwig <hch@xxxxxx> wrote: > > @@ -446,13 +446,14 @@ bool bio_integrity_prep(struct bio *bio) > > if (bio_integrity(bio)) > > return true; > > > > + if (!bi->csum_type) > > + return true; > > Changes look mostly good, but trigger a behavior change for non-PI > metadata format. > > Earlier nop profile was registered for that case. And the block-layer > continued to attach an appropriately sized meta buffer to incoming IO, even > though it did not generate/verify. Hence, IOs don't fail. > > Now also we show that the nop profile is set, but the above > "csum_type" check ensures that > meta buffer is not attached and REQ_INTEGRITY is not set in the bio. > NVMe will start failing IOs with BLK_STS_NOTSUPP now [*]. Yes. I didn't remember that odd case and failed to test it, but I can trivially reproduce it now. Which brings up another issue: bio_integrity_prep allocates the metadata buffer using kmalloc, so we'll leak write random kernel memory to the devices for this case which is ... not good. I guess for stable fixes and backports I'll add a real generate_fn that just zeroes all the memory for now.
