On Wed, Dec 12, 2018 at 2:43 PM Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote: > > On Wed, Dec 12, 2018 at 01:55:28PM -0500, Olga Kornievskaia wrote: > > On Wed, Dec 12, 2018 at 6:31 AM Luis Henriques <lhenriques@xxxxxxxx> wrote: > > > I was wondering if, with the above check, it would make sense to also > > > have an extra patch changing some filesystems (ceph, nfs and cifs) to > > > simply return -EOPNOTSUPP (instead of -EINVAL) when inode_in == > > > inode_out. Something like the diff below (not tested!). > > > > +++ b/fs/nfs/nfs4file.c > > > @@ -136,7 +136,7 @@ static ssize_t nfs4_copy_file_range(struct file *file_in, loff_t pos_in, > > > ssize_t ret; > > > > > > if (file_inode(file_in) == file_inode(file_out)) > > > - return -EINVAL; > > > + return -EOPNOTSUPP; > > > > Please don't change the NFS bits. This is against the NFS > > specifications. RFC 7862 15.2.3 > > > > (snippet) > > SAVED_FH and CURRENT_FH must be different files. If SAVED_FH and > > CURRENT_FH refer to the same file, the operation MUST fail with > > NFS4ERR_INVAL. > > I don't see how that applies. That refers to a requirement _in the > protocol_ that determines what the server MUST do if the client sends > it two FHs which refer to the same file. > > What we're talking about here is how a Linux filesystem behaves when > receiving a copy_file_range() referring to the same file. As long as > the Linux filesystem doesn't react by sending out one of these invalid > protocol messages, I don't see the problem. Ok then this should be changed to call generic_copy_file_range() not returning the EOPNOTSUPP since there is no longer fallback in vfs to call the generic_copy_file_range() and in turn responsibility of each file system.
