Re: [PATCH 20/25] xfs: verify data checksums during media verification

[Christoph Hellwig <hch@lst.de>]

On Wed, Nov 11, 2026 at 12:57:39PM +0100, Pankaj Raghav (Samsung) wrote:
> > +/*
> > + * Data checksums are per-FSB, so we can only validate FSB-aligned regions.
> > + *
> > + * When the alignment leads to an empty range, give up.
> > + */
> 
> A comment here would be helpful about the return values.
> 0 for success,
> 1 for media errors
> errno for other errors.

Ok, I'll add it.

> > +	unsigned int		bbcount;
> > +	xfs_filblks_t		len;
> > +	struct bio		bio;
> > +	struct bio_vec		bv;
> > +	int			error;
> > +
> > +	len = min3(end - bno, xfs_rtcsum_max_len(mp, bno),
> > +			XFS_B_TO_FSBT(mp, folio_size(folio)));
> 
> For large block size systems, if we allocate a single page in the folio
> due to fragmentation, len will always be zero (4096 >> (blocklog > 12)).
> 
> > +	if (!len) {
> > +		*daddr = me->me_end_daddr;
> > +		return 0;
> > +	}
> 
> And we skip those ranges without verifying anything with a success.
> 
> I think we should raise the iosize to a single FSB in
> xfs_verify_alloc_folio and should return ENOMEM if we cannot allocate
> one?

Yes, I'll do that.