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

[linuxtestproject.agent@gmail.com]

Hi Gaurav,

On 12 Oct 2026, Gaurav Pathak wrote:
> syscalls/statx13: Add basic test for STATX_WRITE_ATOMIC on regular file

> #if HAVE_STRUCT_STATX_STX_ATOMIC_WRITE_UNIT_MIN
>
> #if HAVE_STRUCT_STATX_STX_ATOMIC_WRITE_UNIT_MAX_OPT

High: These probes inspect libc's struct statx, but buff.data is the
unconditionally extended statx_fallback. With glibc 2.39, a valid atomic
write response yields two TCONF results and no limit checks. Remove both
HAVE_* guards and the new, unnecessary configure probes; detect support
at runtime.

> 	if (!(buff.data.stx_attributes & STATX_ATTR_WRITE_ATOMIC))
> 		tst_brk(TCONF, "Filesystem does not support STATX_WRITE_ATOMIC");

Medium: Valid-looking limits pass even with stx_mask and
stx_attributes_mask both zero, while nonzero advertised limits with a
missing active attribute produce only TCONF. Validate both masks before
interpreting the fields, and report inconsistent advertised support as
TFAIL rather than skipping it.

> 	TST_EXP_PASS_SILENT(SAFE_STATX(AT_FDCWD, TESTFILE, 0, STATX_BASIC_STATS | STATX_WRITE_ATOMIC, &buff));

Medium: SAFE_STATX aborts with TBROK before the expectation can classify
a syscall failure; returning -1/EIO reproduces this. Since statx is the
syscall under test, call statx(..., &buff.buff) directly inside
TST_EXP_PASS_SILENT.

> 	struct ltp_statx buff;

Low: Allocate the tested syscall output through .bufs using a static
struct ltp_statx pointer and .size = sizeof(*buff), rather than a stack
struct, as required for new LTP tests.

>  * It ensures that supported filesystems (xfs and nfs) correctly report their
>  * atomic write limits to user space when queried via statx().

Low: The filesystem array tests xfs and ext4, not nfs. Describe the
actual coverage using :manpage:`statx(2)`, and document that root is
required to format and mount the test device.

Verdict - Needs revision

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