Re: [PATCH] Don't test nanoseconds for non-LFS interface in io/tst-stat.c

[Adhemerval Zanella <adhemerval.zanella@linaro.org>]

On 16/03/2021 10:56, Stefan Liebler wrote:
> Both new tests io/tst-stat and io/tst-stat-lfs (_FILE_OFFSET_BITS=64)
> are comparing the nanosecond fields with the statx result.  Unfortunately
> e.g. on s390(31bit) those fields are always zero if old KABI with non-LFS
> support is used.  With _FILE_OFFSET_BITS=64 stat is using statx internally.

This might also happens for LFS interface if statx is not supported by the
kernel, since the LFS call will fall back to the use the stat syscall that
has this issue.

Maybe it would be better to make it an internal tests and add a flag
somewhere to just disable it for s390-32. 

> 
> As suggested by Adhemerval this patch disables the nanosecond check for
> non-LFS interface.
> ---
>  io/tst-stat.c | 18 +++++++++++++++++-
>  1 file changed, 17 insertions(+), 1 deletion(-)
> 
> diff --git a/io/tst-stat.c b/io/tst-stat.c
> index 445ac4176c..550128a2a5 100644
> --- a/io/tst-stat.c
> +++ b/io/tst-stat.c
> @@ -26,6 +26,20 @@
>  #include <sys/stat.h>
>  #include <sys/sysmacros.h>
>  #include <unistd.h>
> +#include <kernel_stat.h>
> +
> +#if defined _FILE_OFFSET_BITS && _FILE_OFFSET_BITS == 64
> +/* Test nanoseconds if LFS interface is requested.  */
> +# define TEST_NANOSECONDS 1
> +#elif !XSTAT_IS_XSTAT64
> +/* LFS interface is not requested and we have no LFS support.  E.g. s390(31bit)
> +   is using old KABI with old non-LFS support and the nanoseconds fields are
> +   always zero.  */
> +# define TEST_NANOSECONDS 0
> +#else
> +/* LFS interface is not requested, but we have LFS support.  */
> +# define TEST_NANOSECONDS 1
> +#endif
>  
>  static void
>  stat_check (int fd, const char *path, struct stat *st)
> @@ -91,9 +105,11 @@ do_test (void)
>        TEST_COMPARE (stx.stx_blocks, st.st_blocks);
>  
>        TEST_COMPARE (stx.stx_ctime.tv_sec, st.st_ctim.tv_sec);
> -      TEST_COMPARE (stx.stx_ctime.tv_nsec, st.st_ctim.tv_nsec);
>        TEST_COMPARE (stx.stx_mtime.tv_sec, st.st_mtim.tv_sec);
> +#if TEST_NANOSECONDS
> +      TEST_COMPARE (stx.stx_ctime.tv_nsec, st.st_ctim.tv_nsec);
>        TEST_COMPARE (stx.stx_mtime.tv_nsec, st.st_mtim.tv_nsec);
> +#endif
>      }
>  
>    return 0;
>