On Tue, Jul 21, 2020 at 05:16:16PM +0200, Christoph Hellwig wrote: > On Tue, Jul 21, 2020 at 04:14:37PM +0100, Matthew Wilcox wrote: > > On Tue, Jul 21, 2020 at 05:06:15PM +0200, Christoph Hellwig wrote: > > > On Tue, Jul 21, 2020 at 04:04:32PM +0100, Matthew Wilcox wrote: > > > > I thought you were going to respin this with EREMCHG changed to ENOTBLK? > > > > > > Oh, true. I'll do that ASAP. > > > > Michael, could we add this to manpages? > > Umm, no. -ENOTBLK is internal - the file systems will retry using > buffered I/O and the error shall never escape to userspace (or even the > VFS for that matter). Ah, I made the mistake of believing the comments that I could see in your patch instead of reading the code. Can I suggest deleting this comment: /* * No fallback to buffered IO on errors for XFS, direct IO will either * complete fully or fail. */ and rewording this one: /* * Allow a directio write to fall back to a buffered * write *only* in the case that we're doing a reflink * CoW. In all other directio scenarios we do not * allow an operation to fall back to buffered mode. */ as part of your revised patchset?