On Wed, Feb 24, 2021 at 4:22 PM Luis Henriques <lhenriques@xxxxxxx> wrote: > > Update man-page with recent changes to this syscall. > > Signed-off-by: Luis Henriques <lhenriques@xxxxxxx> > --- > Hi! > > Here's a suggestion for fixing the manpage for copy_file_range(). Note that > I've assumed the fix will hit 5.12. > > man2/copy_file_range.2 | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/man2/copy_file_range.2 b/man2/copy_file_range.2 > index 611a39b8026b..b0fd85e2631e 100644 > --- a/man2/copy_file_range.2 > +++ b/man2/copy_file_range.2 > @@ -169,6 +169,9 @@ Out of memory. > .B ENOSPC > There is not enough space on the target filesystem to complete the copy. > .TP > +.B EOPNOTSUPP > +The filesystem does not support this operation. > +.TP > .B EOVERFLOW > The requested source or destination range is too large to represent in the > specified data types. > @@ -187,7 +190,7 @@ refers to an active swap file. > .B EXDEV > The files referred to by > .IR fd_in " and " fd_out > -are not on the same mounted filesystem (pre Linux 5.3). > +are not on the same mounted filesystem (pre Linux 5.3 and post Linux 5.12). I think you need to drop the (Linux range) altogether. What's missing here is the NFS cross server copy use case. Maybe: ...are not on the same mounted filesystem and the source and target filesystems do not support cross-filesystem copy. You may refer the reader to VERSIONS section where it will say which filesystems support cross-fs copy as of kernel version XXX (i.e. cifs and nfs). > .SH VERSIONS > The > .BR copy_file_range () > @@ -202,6 +205,11 @@ Applications should target the behaviour and requirements of 5.3 kernels. > .PP > First support for cross-filesystem copies was introduced in Linux 5.3. > Older kernels will return -EXDEV when cross-filesystem copies are attempted. > +.PP > +After Linux 5.12, support for copies between different filesystems was dropped. > +However, individual filesystems may still provide > +.BR copy_file_range () > +implementations that allow copies across different devices. Again, this is not likely to stay uptodate for very long. The stable kernels are expected to apply your patch (because it fixes a regression) so this should be phrased differently. If it were me, I would provide all the details of the situation to Michael and ask him to write the best description for this section. Thanks, Amir.
