On Fri, Feb 21, 2025 at 12:04:32PM +0000, Filipe Manana wrote: > On Tue, Feb 18, 2025 at 10:36 PM Anand Jain <anand.jain@xxxxxxxxxx> wrote: > > > > From: Qu Wenruo <wqu@xxxxxxxx> > > > > Update comments that were previously missed. > > > > Signed-off-by: Anand Jain <anand.jain@xxxxxxxxxx> > > --- > > tests/btrfs/226 | 6 ++---- > > 1 file changed, 2 insertions(+), 4 deletions(-) > > > > diff --git a/tests/btrfs/226 b/tests/btrfs/226 > > index 359813c4f394..ce53b7d48c49 100755 > > --- a/tests/btrfs/226 > > +++ b/tests/btrfs/226 > > @@ -22,10 +22,8 @@ _require_xfs_io_command fpunch > > > > _scratch_mkfs >>$seqres.full 2>&1 > > > > -# This test involves RWF_NOWAIT direct IOs, but for inodes with data checksum, > > -# btrfs will fall back to buffered IO unconditionally to prevent data checksum > > -# mimsatch, and that will break RWF_NOWAIT with -EAGAIN. > > -# So here we have to go with nodatasum mount option. > > +# RWF_NOWAIT works only with direct I/O and requires an inode with nodatasum > > +# to avoid checksum mismatches. Otherwise, it falls back to buffered I/O. > > Btw, this is different from what I suggested before here: > > https://lore.kernel.org/fstests/68aa436b-4ddd-4ee7-ad5a-8eca55aae176@xxxxxxxxxx/T/#mb2369802d2e33c9778c62fcb3c0ee47de28b773b > > Which is: > > # RWF_NOWAIT only works with direct IO, which requires an inode with > nodatasum (otherwise it falls back to buffered IO). > > What is being added in this patch: > > +# RWF_NOWAIT works only with direct I/O and requires an inode with nodatasum > +# to avoid checksum mismatches. Otherwise, it falls back to buffered I/O. > > Is confusing because: > > 1) It gives the suggestion RWF_NOWAIT requires nodatasum. > > 2) The part that says "to avoid checksum mismatches", that's not > related to RWF_NOWAIT at all. > That's the reason why direct IO writes against inodes without > nodatasum fallback to buffered IO. > We don't have to explain that - this is not a test to exercise the > fallback after all, all we have to say > is that RWF_NOWAIT needs direct IO and direct IO can only be done > against inodes with nodatasum. > > So you didn't pick my suggestion after all, you just added your own > rephrasing which IMO is confusing. Hi Anand, please talk with Filipe (or more btrfs folks) and make a final decision about how to write this comment. I'll drop this patch from patches-in-queue branch temporarily, until you reach a consensus :) Thanks, Zorro > > > > > _scratch_mount -o nodatasum > > > > # Test a write against COW file/extent - should fail with -EAGAIN. Disable the > > -- > > 2.47.0 > > > > >
