On Thu, Aug 14, 2025 at 03:18:01PM +1000, David Disseldorp wrote: > The copy_file_range syscall can improve copy performance by cloning > extents between cpio archive source and destination files. > Existing read / write based copy logic is retained for fallback in case > the copy_file_range syscall is unsupported or unavailable due to > cross-filesystem EXDEV, etc. > > Clone or reflink, as opposed to copy, of source file extents into the > output cpio archive may (e.g. on Btrfs and XFS) require alignment of the > output to the filesystem block size. This could be achieved by inserting > padding entries into the cpio archive manifest. > > Signed-off-by: David Disseldorp <ddiss@xxxxxxx> > --- > usr/gen_init_cpio.c | 14 +++++++++++++- > 1 file changed, 13 insertions(+), 1 deletion(-) Thanks. I like introducing copy_file_range() here, it reduces the cpio generation time on my system by a about 30% on a btrfs filesystem. May cpio_mkfile_csum() now the slowest part? Kind regards, Nicolas
