On Thu, Mar 04, 2021 at 07:24:02PM +0100, Alejandro Colomar (man-pages) wrote: > Hi Darrick, > > On 3/4/21 6:13 PM, Darrick J. Wong wrote: > > On Thu, Mar 04, 2021 at 10:38:07AM +0100, Alejandro Colomar wrote: > > > +However, on some virtual filesystems, > > > +the call failed to copy, while still reporting success. > > > > ...success, or merely a short copy? > > Okay. > > > > > (The rest looks reasonable (at least by c_f_r standards) to me.) > > I'm curious, what does "c_f_r standards" mean? :) c_f_r is shorthand for "copy_file_range". As for standards... well... I'll just say that this being the /second/ major shift in behavior reflects our poor community development processes. The door to general cross-fs copies should not have been thrown open with as little testing as it did. There are legendary dchinner rants about how obviously broken the generic fallback was when it was introduced. There's a reason why we usually wire up new kernel functionality on an opt-in basis, and that is to foster gradual enablement as QA resources permit. It's one thing for maintainers to blow up their own subsystems in isolation, and an entirely different thing to do it between projects with no coordination. Did c_f_r work between an ext4 and an xfs? I have no idea. It seemed to work between xfses of a similar vintage and featureset, at least, but that's about as much testing as I have ever managed. --D > > Cheers, > > Alex > > -- > Alejandro Colomar > Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/ > http://www.alejandro-colomar.es/