Re: [PATCH v1 2/2] fs/writeback: skip inodes with potential writeback hang in wait_sb_inodes()

[Joanne Koong <joannelkoong@gmail.com>]

On Wed, Nov 26, 2025 at 2:55 AM David Hildenbrand (Red Hat)
<david@kernel.org> wrote:
> >
> >> having a flag that states something like that that
> >> "AS_NO_WRITEBACK_WAIT_ON_DATA_SYNC" would probable be what we would want
> >> to add to avoid waiting for writeback with clear semantics why it is ok
> >> in that specific scenario.
> >
> > Having a separate AS_NO_WRITEBACK_WAIT_ON_DATA_SYNC mapping flag
> > sounds reasonable to me and I agree is more clearer semantically.
>
> Good. Then it's clear that we are not waiting because writeback is
> shaky, but because even if it would be working, because we don't have to
> because there are no such guarantees.
>
> Maybe
>
> AS_NO_DATA_INTEGRITY
>
> or similar would be cleaner, I'll have to leave that to you and Miklos
> to decide what exactly the semantics are that fuse currently doesn't
> provide.

After reading Miklos's reply, I must have misunderstood this then - my
understanding was that the reason we couldn't guarantee data integrity
in fuse was because of the temp pages design where checking the
writeback flag on the real folio doesn't reflect writeback state, but
that removing the temp pages and using the real folio now does
guarantee this. But it seems like it's not as simple as that and
there's no data integrity guarantees for other reasons.

Changing this to AS_NO_DATA_INTEGRITY sounds good to me, if that
sounds good to Miklos as well. Or do you have another preference,
Miklos?

Thanks,
Joanne
>
>
> --
> Cheers
>
> David