[LTP] syscalls/statx13: Add basic test for STATX_WRITE_ATOMIC on regular file

[linuxtestproject.agent@gmail.com]

Hi Gaurav,

On Thu Sep 17 16:23:04 2026 +0530, Gaurav Pathak wrote:
> syscalls/statx13: Add basic test for STATX_WRITE_ATOMIC on regular file

> Fixes: #1224
> 
> Signed-off-by: Gaurav Pathak <gaurav.pathak@suse.com>
> Closes: #1224 or a Link tag to reference an issue.

Fixes: tags must reference a commit SHA present in git history, not an issue.
Use Closes: #1224 to reference the issue. Also remove the unedited template
instruction "or a Link tag to reference an issue." from the Closes tag.

> diff --git a/configure.ac b/configure.ac
> index 18bfdb88c..72f423c56 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -181,7 +181,7 @@ AC_CHECK_MEMBERS([struct iocb.aio_rw_flags],,,[#include <linux/aio_abi.h>])
>  AC_CHECK_MEMBERS([struct fanotify_event_info_fid.fsid.__val],,,[#include <sys/fanotify.h>])
>  AC_CHECK_MEMBERS([struct perf_event_mmap_page.aux_head],,,[#include <linux/perf_event.h>])
>  AC_CHECK_MEMBERS([struct sigaction.sa_sigaction],[],[],[#include <signal.h>])
> -AC_CHECK_MEMBERS([struct statx.stx_mnt_id, struct statx.stx_dio_mem_align],,,[
> +AC_CHECK_MEMBERS([struct statx.stx_mnt_id, struct statx.stx_dio_mem_align, struct statx.stx_atomic_write_unit_max_opt],,,[
>  #define _GNU_SOURCE
>  #include <sys/stat.h>
>  ])

configure.ac checks may only enable fallback API definitions in
include/lapi/. Fallback definitions for struct statx extensions and atomic
write flags should be added to include/lapi/stat.h instead.

> diff --git a/testcases/kernel/syscalls/statx/statx13.c b/testcases/kernel/syscalls/statx/statx13.c
> new file mode 100644
> index 000000000..ea42a102c
> --- /dev/null
> +++ b/testcases/kernel/syscalls/statx/statx13.c

Add an entry for statx13 to runtest/syscalls.

> +/*\
> + * This test validates the STATX_WRITE_ATOMIC feature (introduced in Linux 6.13).
> + * It ensures that supported filesystems (xfs as of now) correctly report their
> + * atomic write limits to user space when queried via statx().
> + *
> + * The test performs the following validations:
> + * - Creates a test file using O_DIRECT (a prerequisite for atomic writes).

Insert a blank line before the bulleted list so Sphinx can parse the reST
block correctly. Also, reference the syscall as :manpage:`statx(2)`.

> +#define TESTFILE MNTPOINT"/testfile"

Add a space between concatenated string literals: MNTPOINT "/testfile".

> +#define _GNU_SOURCE
> +#include <sys/param.h>
> +#include "tst_test.h"

Include "lapi/stat.h". Fallback definitions for STATX_WRITE_ATOMIC,
STATX_ATTR_WRITE_ATOMIC, and atomic write fields in struct statx must be
provided in include/lapi/stat.h so the test compiles on older C libraries.

> +#ifdef HAVE_STRUCT_STATX_STX_ATOMIC_WRITE_UNIT_MAX_OPT
> +	if (buff.stx_atomic_write_unit_max_opt == 0) {

Do not place #ifdef guards inside function bodies. Define the fallback
struct in include/lapi/stat.h so the test code compiles unconditionally.

> +		if (buff.stx_atomic_write_unit_max_opt > buff.stx_atomic_write_unit_max)
> +			tst_res(TFAIL, "stx_atomic_write_unit_max_opt (%u) exceeds max (%u)",
> +					buff.stx_atomic_write_unit_max_opt,
> +					buff.stx_atomic_write_unit_max);
> +
> +		else if (buff.stx_atomic_write_unit_max_opt < buff.stx_atomic_write_unit_min)

Remove the blank line between if and else if to follow kernel coding style.

> +static void setup(void)
> +{
> +	char *data_buff = SAFE_MEMALIGN(ALIGNMENT, WRITE_SIZE);
> +
> +	if (strcmp(tst_device->fs_type, "xfs") && strcmp(tst_device->fs_type, "ext4"))
> +		tst_brk(TCONF, "This test only supports ext4 and xfs");
> +
> +	umask(0);
> +	memset(data_buff, '@', WRITE_SIZE);
> +
> +	file_fd =  SAFE_OPEN(TESTFILE, O_RDWR | O_CREAT | O_DIRECT, MODE);
> +	SAFE_WRITE(SAFE_WRITE_ALL, file_fd, data_buff, WRITE_SIZE);
> +}

data_buff is never freed, leaking memory. Move the allocation after the
filesystem check and call free(data_buff) after SAFE_WRITE(). Also remove
the double space after '=' in file_fd assignment.

> +static void cleanup(void)
> +{
> +	if (file_fd > -1)
> +		SAFE_CLOSE(file_fd);
> +}

Use if (file_fd != -1) instead of file_fd > -1 to match the LTP convention.

Verdict - Needs revision

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