fuse_buf_copy_flags

Don't use splice(2)

Always fall back to using read and write instead of splice(2) to copy data from one file descriptor to another.

If this flag is not set, then only fall back if splice is unavailable.

Force splice

Always use splice(2) to copy data from one file descriptor to another. If splice is not available, return -EINVAL.

Try to move data with splice.

If splice is used, try to move pages from the source to the destination instead of copying. See documentation of SPLICE_F_MOVE in splice(2) man page.

Don't block on the pipe when copying data with splice

Makes the operations on the pipe non-blocking (if the pipe is full or empty). See SPLICE_F_NONBLOCK in the splice(2) man page.