diff options
Diffstat (limited to 'src/internal/poll/copy_file_range_linux.go')
| -rw-r--r-- | src/internal/poll/copy_file_range_linux.go | 24 |
1 files changed, 14 insertions, 10 deletions
diff --git a/src/internal/poll/copy_file_range_linux.go b/src/internal/poll/copy_file_range_linux.go index 66408e4590..ba33f5145d 100644 --- a/src/internal/poll/copy_file_range_linux.go +++ b/src/internal/poll/copy_file_range_linux.go @@ -41,18 +41,22 @@ func CopyFileRange(dst, src *FD, remain int64) (written int64, handled bool, err } n, err := copyFileRange(dst, src, int(max)) switch err { + case syscall.ENOSYS: + // copy_file_range(2) was introduced in Linux 4.5. + // Go supports Linux >= 2.6.33, so the system call + // may not be present. + // + // If we see ENOSYS, we have certainly not transferred + // any data, so we can tell the caller that we + // couldn't handle the transfer and let them fall + // back to more generic code. + return 0, false, nil case syscall.EXDEV, syscall.EINVAL, syscall.EIO, syscall.EOPNOTSUPP, syscall.EPERM: // Prior to Linux 5.3, it was not possible to - // copy_file_range across file systems. An attempt - // to do this will result in a EXDEV error. - // - // Even though we have checked the kernel version and blocked - // the attempts to copy_file_range(2) when the kernel version - // is older than 5.3, but until now the latest kernel (5.19.x) - // may still return EXDEV error in certain cases. - // - // If we see EXDEV, we have not transferred any data, - // and we can let the caller fall back to generic code. + // copy_file_range across file systems. Similarly to + // the ENOSYS case above, if we see EXDEV, we have + // not transferred any data, and we can let the caller + // fall back to generic code. // // As for EINVAL, that is what we see if, for example, // dst or src refer to a pipe rather than a regular |