When building in a RHEL 7 container on a RHEL 8 host, the current configure check will detect a working SYS_copy_file_range() syscall.
Later when the resulting smbd binary is run in a RHEL 7 container on a RHEl 7 (vs 8 on the build host) host, SYS_copy_file_range() will fail with EOPNOTSUPP.
We have to catch this in vfs_default and fallback to userspace copy in that case.
This bug was referenced in samba master:
Created attachment 16736 [details]
Patch for 4.15 cherry-picked from master
Pushed to autobuild-v4-15-test.
This bug was referenced in samba v4-15-test:
Closing out bug report.
This bug was referenced in samba v4-15-stable (Release samba-4.15.0rc3):