> On Oct 26, 2018, at 8:54 AM, Olga Kornievskaia <aglo@xxxxxxxxx> wrote: > > Hi Chuck, > > In the context of doing a copy between different "types" of > filesystems, it was pointed out to me that NFS has many types: > nfs4_fs_type, nfs4_remote_fs_type, nfs4_remote_referral_fs_type, > nfs4_referral_fs_type. So doing a simple check that fs type of "in" > and "out" might not be sufficient. Do you see any issues allowing a > copy offload between different types? Basically checking that "in" and > "out" descriptions come from any of the these types? I'm no expert... so what follows is an uninformed opinion. All of these are NFSv4 file systems. But I don't think that's an adequate check (it's necessary, but not sufficient). The minor version of the mount point has to be 2 or higher, and the client must confirm that the mounted server supports copy offload (because all NFSv4.2 features are OPTIONAL). -- Chuck Lever
