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 <jack@xxxxxxxx> SUSE Labs, CR
