[BUG / BUILD FAILURE] selftests/fuse: build failure with libfuse < 3.17.0 (RHEL 10 / fuse3-3.16.2)

[BUG / BUILD FAILURE] selftests/fuse: build failure with libfuse < 3.17.0 (RHEL 10 / fuse3-3.16.2)

[Venkat Rao Bagalkote]

Hi Miklos, Luis,


IBM CI has reported a build failure, while building selftests/fuse, due 
to missing definitions in libfuse3 headers.

Environment:

OS: RHEL 10 (ppc64le)
Kernel: upstream (linux-next / mainline)
libfuse package: fuse3-devel-3.16.2-5.el10.ppc64le (pkg-config 
--modversion fuse3 -> 3.16.2)

Build Errors:

In fuse_acl_cache_test.c & fuse_symlink_cache_test.c:

fuse_acl_cache_test.c: In function ‘fs_init’:
fuse_acl_cache_test.c:105:17: error: implicit declaration of function 
‘fuse_set_feature_flag’ [-Wimplicit-function-declaration]
   105 |                 fuse_set_feature_flag(conn, FUSE_CAP_POSIX_ACL);
       |                 ^~~~~~~~~~~~~~~~~~~~~
make: *** [../../lib.mk:226: 
/home/upstreamci/linux/tools/testing/selftests/filesystems/fuse/fuse_acl_cache_test] 
Error 1

In fuse_mnt.c:

fuse_mnt.c: In function ‘test_readdir’:
fuse_mnt.c:51:35: error: ‘FUSE_FILL_DIR_DEFAULTS’ undeclared (first use 
in this function); did you mean ‘FUSE_FILL_DIR_PLUS’?
    51 |         filler(buf, ".", NULL, 0, FUSE_FILL_DIR_DEFAULTS);
       |                                   ^~~~~~~~~~~~~~~~~~~~~~
       |                                   FUSE_FILL_DIR_PLUS
make: *** [../../lib.mk:226: 
/home/upstreamci/linux/tools/testing/selftests/filesystems/fuse/fuse_mnt] 
Error 1


If you happen to fix this, please add below tag.


Reported-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>

Regards,

Venkat.

Re: [BUG / BUILD FAILURE] selftests/fuse: build failure with libfuse < 3.17.0 (RHEL 10 / fuse3-3.16.2)

[Luis Henriques]

Hi Venkat,

[ CC'ing the fuse mailing-list ]

On Thu, Nov 12 2026, Venkat Rao Bagalkote wrote:

> Hi Miklos, Luis,
>
>
> IBM CI has reported a build failure, while building selftests/fuse, due to
> missing definitions in libfuse3 headers.
>
> Environment:
>
> OS: RHEL 10 (ppc64le)
> Kernel: upstream (linux-next / mainline)
> libfuse package: fuse3-devel-3.16.2-5.el10.ppc64le (pkg-config --modversion
> fuse3 -> 3.16.2)
>
> Build Errors:
>
> In fuse_acl_cache_test.c & fuse_symlink_cache_test.c:
>
> fuse_acl_cache_test.c: In function ‘fs_init’:
> fuse_acl_cache_test.c:105:17: error: implicit declaration of function
> ‘fuse_set_feature_flag’ [-Wimplicit-function-declaration]
>   105 |                 fuse_set_feature_flag(conn, FUSE_CAP_POSIX_ACL);
>       |                 ^~~~~~~~~~~~~~~~~~~~~
> make: *** [../../lib.mk:226:
> /home/upstreamci/linux/tools/testing/selftests/filesystems/fuse/fuse_acl_cache_test]
> Error 1
>
> In fuse_mnt.c:
>
> fuse_mnt.c: In function ‘test_readdir’:
> fuse_mnt.c:51:35: error: ‘FUSE_FILL_DIR_DEFAULTS’ undeclared (first use in this
> function); did you mean ‘FUSE_FILL_DIR_PLUS’?
>    51 |         filler(buf, ".", NULL, 0, FUSE_FILL_DIR_DEFAULTS);
>       |                                   ^~~~~~~~~~~~~~~~~~~~~~
>       |                                   FUSE_FILL_DIR_PLUS
> make: *** [../../lib.mk:226:
> /home/upstreamci/linux/tools/testing/selftests/filesystems/fuse/fuse_mnt] Error
> 1

Thank you for your report.

This issue was already identified and fixed by Sasha[1].  Looks like there
was some problem when my patchest[2] was applied to the git tree:
commit 3e14f079d7a0 ("selftests/fuse: add fuse symlink caching test")
dropped the actual test code that was present in the patch.

I believe Sasha's fix wasn't yet applied, but I guess that will eventually
happen.

[1] https://lore.kernel.org/all/20261026194008.274349-1-sashal@kernel.org/
[2] https://lore.kernel.org/all/20261001164916.15311-1-luis@igalia.com

Cheers,
-- 
Luís