On Fri, Oct 26, 2018 at 08:45:38AM -0400, Olga Kornievskaia wrote: > On Thu, Oct 25, 2018 at 6:27 PM Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote: > > > > On Thu, Oct 25, 2018 at 05:51:47PM -0400, Olga Kornievskaia wrote: > > > - if (file_in->f_inode->i_sb != file_out->f_inode->i_sb) > > > + if (file_in->f_inode->i_sb->s_type != file_out->f_inode->i_sb->s_type) > > > > Isn't it simpler to do: > > > > if (file_in->f_inode->i_sb->s_type != &nfs4_fs_type) > > I don't believe that's sufficient. What if "in" fs was NFS and "out" > fs was CIFS? This is the NFS implementation, so you know that 'out' is an NFS file. > > But now I've done some grepping, and I wonder whether it's possible > > / desirable to also copy between inodes on a nfs4_remote_fs_type, > > nfs4_remote_referral_fs_type, nfs4_referral_fs_type or nfs4_xdev_fs_type. > > I haven't kept up with NFS development for a while, so maybe none of > > those are possible. > > Thank you for pointing it out. Grepping thru the code, don't believe > the last one is used but for the migration and replication types, I > don't know if there are any caveats that would preclude support for > copy offload I'll check with Chuck Lever. Then the check should be > that "in" and "out" are any of the 4 NFS types.