On Mon 10-04-17 07:39:43, Christoph Hellwig wrote:
> On Mon, Apr 10, 2017 at 02:37:50PM +0200, Jan Kara wrote:
> > I don't understand here. Do you want that all filesystems support NOWAIT
> > direct IO?
>
> No. Per-file_system_type is way to coarse grained. All feature flag
> needs to be per-file_operation at least for cases like ext4 with our
> without extents (or journal) XFS v4 vs v5, different NFS versions, etc.
Ah, I see your point now. Thanks for patience. I think we could make this
work by making generic_file_write/read_iter() refuse NOWAIT IO with
EOPNOTSUPP and then only modify those few filesystems that implement their
own iter helpers and will not initially support NOWAIT IO. Sounds easy
enough.
Honza
--
Jan Kara <[email protected]>
SUSE Labs, CR
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