diff options
Diffstat (limited to 'library/std/src/sys/unix/kernel_copy.rs')
| -rw-r--r-- | library/std/src/sys/unix/kernel_copy.rs | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/library/std/src/sys/unix/kernel_copy.rs b/library/std/src/sys/unix/kernel_copy.rs index 99533dd3c07..ac2fcfcb53f 100644 --- a/library/std/src/sys/unix/kernel_copy.rs +++ b/library/std/src/sys/unix/kernel_copy.rs @@ -438,7 +438,6 @@ pub(super) enum CopyResult { /// Callers must handle fallback to a generic copy loop. /// `Fallback` may indicate non-zero number of bytes already written /// if one of the files' cursor +`max_len` would exceed u64::MAX (`EOVERFLOW`). -/// If the initial file offset was 0 then `Fallback` will only contain `0`. pub(super) fn copy_regular_files(reader: RawFd, writer: RawFd, max_len: u64) -> CopyResult { use crate::cmp; @@ -462,10 +461,10 @@ pub(super) fn copy_regular_files(reader: RawFd, writer: RawFd, max_len: u64) -> while written < max_len { let copy_result = if has_copy_file_range { let bytes_to_copy = cmp::min(max_len - written, usize::MAX as u64); - // cap to 2GB chunks in case u64::MAX is passed in as file size and the file has a non-zero offset - // this allows us to copy large chunks without hitting the limit, - // unless someone sets a file offset close to u64::MAX - 2GB, in which case the fallback would kick in - let bytes_to_copy = cmp::min(bytes_to_copy as usize, 0x8000_0000usize); + // cap to 1GB chunks in case u64::MAX is passed as max_len and the file has a non-zero seek position + // this allows us to copy large chunks without hitting EOVERFLOW, + // unless someone sets a file offset close to u64::MAX - 1GB, in which case a fallback would be required + let bytes_to_copy = cmp::min(bytes_to_copy as usize, 0x4000_0000usize); let copy_result = unsafe { // We actually don't have to adjust the offsets, // because copy_file_range adjusts the file offset automatically @@ -560,6 +559,7 @@ fn sendfile_splice(mode: SpliceMode, reader: RawFd, writer: RawFd, len: u64) -> let mut written = 0u64; while written < len { + // according to its manpage that's the maximum size sendfile() will copy per invocation let chunk_size = crate::cmp::min(len - written, 0x7ffff000_u64) as usize; let result = match mode { |