[PATCH] tests/file_handle.c: skip if fs can't do handles

[Dmitry V. Levin]

On Mon, May 03, 2021 at 01:12:13PM +0000, Alyssa Ross wrote:
> Quoting name_to_handle_at(2):
> 
> > Some care is needed here as EOVERFLOW can also indicate that no file
> > handle is available for this particular name in a filesystem which
> > does normally support file-handle lookup.  This case can be detected
> > when the EOVERFLOW error is returned without handle_bytes being
> > increased.
> 
> This patch handles that case, resolving 20 failures for me on ZFS, and
> making `make check' able to run successfully.

I must admit I'm a bit surprised that a filesystem supporting file-handle
lookups can fail to return a file handle for ".".

> ---
>  tests/file_handle.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/tests/file_handle.c b/tests/file_handle.c
> index 86d51b63..da544c2f 100644
> --- a/tests/file_handle.c
> +++ b/tests/file_handle.c
> @@ -206,8 +206,11 @@ main(void)
>  	       path, path_secontext,
>  	       handle->handle_bytes, &mount_id);
>  
> -	assert(syscall(__NR_name_to_handle_at, fdcwd, path, handle, &mount_id,
> -		flags) == 0);
> +	errno = 0;
> +	syscall(__NR_name_to_handle_at, fdcwd, path, handle, &mount_id, flags);
> +	if (EOVERFLOW == errno)
> +		perror_msg_and_skip("name_to_handle_at");
> +	assert(!errno);

Please check the syscall return value here, e.g.:

	if (syscall(__NR_name_to_handle_at, fdcwd, path, handle, &mount_id,
		    flags)) {
		if (EOVERFLOW == errno)
			perror_msg_and_skip("name_to_handle_at");
		else
			perror_msg_and_fail("name_to_handle_at");
	}

-- 
ldv