Re: [PATCH 4/7] fuse[24]fs: suppress clang warnings which were breaking the github CI

Darrick J. Wong
2026-05-05T00:20:06Z

On Mon, May 04, 2026 at 07:32:58PM -0400, Theodore Ts'o wrote:
> fuse[24]fs.c defines some functions which might or might not be used
> depending on the version of the fuse library installed on the system.
> Unfortunately while gcc won't complain if there are static inline
> functions which are not used, clang will only suppress such complaints
> if the static inline functions are in a header file.

<groan>

> Since the github CI runs a test build with -Wall -Werror this was
> breaking the CI build.
>
> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
> ---
> fuse4fs/fuse4fs.c | 21 +++++++++++++++++++++
> misc/fuse2fs.c | 21 +++++++++++++++++++++
> 2 files changed, 42 insertions(+)
>
> diff --git a/fuse4fs/fuse4fs.c b/fuse4fs/fuse4fs.c
> index 13e1aae4b..b883083f8 100644
> --- a/fuse4fs/fuse4fs.c
> +++ b/fuse4fs/fuse4fs.c
> @@ -502,6 +502,27 @@ static inline off_t FUSE4FS_FSB_TO_B(const struct fuse4fs *ff, blk64_t bno)
> return bno << ff->blocklog;
> }
>
> +#ifdef __clang__
> +#define SUPPRESS_UNUSED_FUNCTION(func) (void)func
> +/*
> + * These functions might or might not be used depending on the version
> + * of the fuse library installed on the system. Unfortunately while
> + * gcc won't complain if there are static inline functions which are
> + * not used, clang will only suppress such complaints if the static
> + * inline functions are in a header file.
> + */
> +void fuse2fs_shut_up_stupid_clang_warnings(void)
> +{
> + SUPPRESS_UNUSED_FUNCTION(fuse2fs_shut_up_stupid_clang_warnings);

Why is this stupid recursive shi ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
even necessary?

> + SUPPRESS_UNUSED_FUNCTION(round_up);
> + SUPPRESS_UNUSED_FUNCTION(round_down);
> + SUPPRESS_UNUSED_FUNCTION(FUSE4FS_B_TO_FSBT);
> + SUPPRESS_UNUSED_FUNCTION(FUSE4FS_OFF_IN_FSB);
> + SUPPRESS_UNUSED_FUNCTION(FUSE4FS_B_TO_FSB);
> + SUPPRESS_UNUSED_FUNCTION(FUSE4FS_FSB_TO_B);

Hrmm some of these aren't strictly necessary, but ... oh. The first
three are actively used in the punch hole helpers, but that only applies
on a platform that *supports* hole punching. So my guess is that these
clang warnings appear on macos, where there isn't holepunching?

--D

> +}
> +#endif
> +
> static double gettime_monotonic(void)
> {
> #ifdef CLOCK_MONOTONIC
> diff --git a/misc/fuse2fs.c b/misc/fuse2fs.c
> index 0f4781bc4..c46cfc236 100644
> --- a/misc/fuse2fs.c
> +++ b/misc/fuse2fs.c
> @@ -339,6 +339,27 @@ static inline off_t FUSE2FS_FSB_TO_B(const struct fuse2fs *ff, blk64_t bno)
> return bno << ff->blocklog;
> }
>
> +#ifdef __clang__
> +#define SUPPRESS_UNUSED_FUNCTION(func) (void)func
> +/*
> + * These functions might or might not be used depending on the version
> + * of the fuse library installed on the system. Unfortunately while
> + * gcc won't complain if there are static inline functions which are
> + * not used, clang will only suppress such complaints if the static
> + * inline functions are in a header file.
> + */
> +void fuse2fs_shut_up_stupid_clang_warnings(void)
> +{
> + SUPPRESS_UNUSED_FUNCTION(fuse2fs_shut_up_stupid_clang_warnings);
> + SUPPRESS_UNUSED_FUNCTION(round_up);
> + SUPPRESS_UNUSED_FUNCTION(round_down);
> + SUPPRESS_UNUSED_FUNCTION(FUSE2FS_B_TO_FSBT);
> + SUPPRESS_UNUSED_FUNCTION(FUSE2FS_OFF_IN_FSB);
> + SUPPRESS_UNUSED_FUNCTION(FUSE2FS_B_TO_FSB);
> + SUPPRESS_UNUSED_FUNCTION(FUSE2FS_FSB_TO_B);
> +}
> +#endif
> +
> static double gettime_monotonic(void)
> {
> #ifdef CLOCK_MONOTONIC
> --
> 2.53.0
>
>