This patchset adds copy_file_range() support to gen_init_cpio. When
combined with data segment alignment, large-file archiving performance
is improved on Btrfs and XFS due to reflinks (see 7/7 benchmarks).
cpio data segment alignment is provided by "bending" the newc spec
to zero-pad the filename field. GNU cpio and Linux initramfs extractors
handle this fine as long as PATH_MAX isn't exceeded.
Changes since v1 RFC
- add alignment patches 6-7
- slightly rework commit and error messages
- rename l->len to avoid 1/i confusion
David Disseldorp (7):
gen_init_cpio: write to fd instead of stdout stream
gen_init_cpio: support -o <output_path> parameter
gen_init_cpio: attempt copy_file_range for file data
gen_init_cpio: avoid duplicate strlen calls
gen_initramfs.sh: use gen_init_cpio -o parameter
docs: initramfs: file data alignment via name padding
gen_init_cpio: add -a <data_align> as reflink optimization
.../driver-api/early-userspace/buffer-format.rst | 5 +
usr/gen_init_cpio.c | 234 ++++++++++++++-------
usr/gen_initramfs.sh | 7 +-
3 files changed, 166 insertions(+), 80 deletions(-)
