movefile: support in-kernel file copying on Linux (bug 607868)
Perform in-kernel file copying when possible, and also support
reflinks and sparse files. If the optimized implementation
fails at runtime, gracefully fallback to a plain read/write
loop.
Compile-time and run-time fallbacks are implemented, so that
any incompatiblities will be handled gracefully. For example,
if the code is compiled on a system that supports the
copy_file_range syscall, but at run-time an older kernel that
does not support this syscall is detected, it will be handled
gracefully. There are similar fallbacks for lack of lseek
SEEK_DATA and sendfile support.
X-Gentoo-Bug: 607868
X-Gentoo-Bug-Url: https://bugs.gentoo.org/show_bug.cgi?id=607868
Acked-by: Brian Dolbec <dolsen@gentoo.org>
7 files changed
