Re: [PATCH] fstests Fix build errors on kernels before v5.1

[Zorro Lang <zlang@kernel.org>]

On Wed, Jul 22, 2026 at 11:35:44AM +0200, Andrey Albershteyn wrote:
> On 2026-07-22 07:22:58, Lukas Herbolt wrote:
> > The FAN_REPORT_FID and fanotify_event_info_fid were introduced
> > in v5.1. Currently there is no check if the kernel supports it
> > making xfstests build to fail on older kernels.
> > 
> > Fixes: 29d120e41c3d ("generic: test fsnotify filesystem error reporting")
> > 
> > Signed-off-by: Lukas Herbolt <lukas@herbolt.com>
> 
> Looks good to me
> Reviewed-by: Andrey Albershteyn <aalbersh@kernel.org>
> 
> > ---
> >  configure.ac          |  1 +
> >  include/builddefs.in  |  1 +
> >  m4/package_libcdev.m4 | 14 ++++++++++++++
> >  src/Makefile          |  6 +++++-
> >  4 files changed, 21 insertions(+), 1 deletion(-)
> > 
> > diff --git a/configure.ac b/configure.ac
> > index 441f543c6089..feb24ddd8854 100644
> > --- a/configure.ac
> > +++ b/configure.ac
> > @@ -74,6 +74,7 @@ AC_NEED_INTERNAL_XFS_IOC_EXCHANGE_RANGE
> >  AC_HAVE_FICLONE
> >  AC_HAVE_TRIVIAL_AUTO_VAR_INIT
> >  AC_HAVE_FILE_GETATTR
> > +AC_HAVE_FANOTIFY_FID
> >  
> >  AC_CHECK_FUNCS([renameat2])
> >  AC_CHECK_FUNCS([reallocarray])
> > diff --git a/include/builddefs.in b/include/builddefs.in
> > index 708d75b24d76..8e9e2e3b4113 100644
> > --- a/include/builddefs.in
> > +++ b/include/builddefs.in
> > @@ -75,6 +75,7 @@ HAVE_RLIMIT_NOFILE = @have_rlimit_nofile@
> >  NEED_INTERNAL_XFS_IOC_EXCHANGE_RANGE = @need_internal_xfs_ioc_exchange_range@
> >  HAVE_FICLONE = @have_ficlone@
> >  HAVE_FILE_GETATTR = @have_file_getattr@
> > +HAVE_FANOTIFY_FID = @have_fanotify_fid@
> >  
> >  GCCFLAGS = -std=gnu11 -funsigned-char -fno-strict-aliasing -Wall
> >  SANITIZER_CFLAGS += @autovar_init_cflags@
> > diff --git a/m4/package_libcdev.m4 b/m4/package_libcdev.m4
> > index 17f57f427410..340cdad3faf9 100644
> > --- a/m4/package_libcdev.m4
> > +++ b/m4/package_libcdev.m4
> > @@ -102,3 +102,17 @@ AC_DEFUN([AC_HAVE_FILE_GETATTR],
> >         AC_MSG_RESULT(yes)],[AC_MSG_RESULT(no)])
> >      AC_SUBST(have_file_getattr)
> >    ])
> > +
> > +# Check if we have fanotify FID support (Linux 5.1+)
> > +AC_DEFUN([AC_HAVE_FANOTIFY_FID],
> > +  [ AC_MSG_CHECKING([for fanotify FID support])
> > +    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
> > +#include <sys/fanotify.h>
> > +    ]], [[
> > +       int x = FAN_REPORT_FID;
> > +       struct fanotify_event_info_fid fid;
> > +       (void)x; (void)fid;
> > +    ]])],[have_fanotify_fid=yes
> > +       AC_MSG_RESULT(yes)],[AC_MSG_RESULT(no)])
> > +    AC_SUBST(have_fanotify_fid)
> > +  ])
> > diff --git a/src/Makefile b/src/Makefile
> > index 31ac43b215e9..847fb168181e 100644
> > --- a/src/Makefile
> > +++ b/src/Makefile
> > @@ -36,7 +36,7 @@ LINUX_TARGETS = xfsctl bstat t_mtab getdevicesize preallo_rw_pattern_reader \
> >  	fscrypt-crypt-util bulkstat_null_ocount splice-test chprojid_fail \
> >  	detached_mounts_propagation ext4_resize t_readdir_3 splice2pipe \
> >  	uuid_ioctl t_snapshot_deleted_subvolume fiemap-fault min_dio_alignment \
> > -	rw_hint fs-monitor
> > +	rw_hint
> >  
> >  EXTRA_EXECS = dmerror fill2attr fill2fs fill2fs_check scaleread.sh \
> >  	      btrfs_crc32c_forged_name.py popdir.pl popattr.py \
> > @@ -107,6 +107,10 @@ ifeq ($(HAVE_FICLONE),yes)
> >       TARGETS += t_reflink_read_race
> >  endif
> >  
> > +ifeq ($(HAVE_FANOTIFY_FID),yes)
> > +     TARGETS += fs-monitor
> ...
> >       LINUX_TARGETS += t_btrfs_received_uuid_ioctl
> 
> hah just noticed that fstests "supports" different targets (darwin,
> freebsd), not sure if it works at all

As far as I know, fstests is currently a Linux filesystem testing suite. I don't
recall us ever being asked to support FreeBSD or other operating systems, though
I'm not sure if anyone is actually using it that way :)

> 
> -- 
> - Andrey
>