diff --git a/library/std/src/sys/unix/kernel_copy.rs b/library/std/src/sys/unix/kernel_copy.rs index 7d49bbdcbe063..4d17a1b000229 100644 --- a/library/std/src/sys/unix/kernel_copy.rs +++ b/library/std/src/sys/unix/kernel_copy.rs @@ -89,6 +89,12 @@ enum FdMeta { NoneObtained, } +#[derive(PartialEq)] +enum FdHandle { + Input, + Output, +} + impl FdMeta { fn maybe_fifo(&self) -> bool { match self { @@ -114,12 +120,14 @@ impl FdMeta { } } - fn copy_file_range_candidate(&self) -> bool { + fn copy_file_range_candidate(&self, f: FdHandle) -> bool { match self { // copy_file_range will fail on empty procfs files. `read` can determine whether EOF has been reached // without extra cost and skip the write, thus there is no benefit in attempting copy_file_range - FdMeta::Metadata(meta) if meta.is_file() && meta.len() > 0 => true, - FdMeta::NoneObtained => true, + FdMeta::Metadata(meta) if f == FdHandle::Input && meta.is_file() && meta.len() > 0 => { + true + } + FdMeta::Metadata(meta) if f == FdHandle::Output && meta.is_file() => true, _ => false, } } @@ -197,7 +205,9 @@ impl SpecCopy for Copier<'_, '_, R, W> { written += flush()?; let max_write = reader.min_limit(); - if input_meta.copy_file_range_candidate() && output_meta.copy_file_range_candidate() { + if input_meta.copy_file_range_candidate(FdHandle::Input) + && output_meta.copy_file_range_candidate(FdHandle::Output) + { let result = copy_regular_files(readfd, writefd, max_write); result.update_take(reader);