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

[Petr Vorel]

Hi all,

> This patch adds a new test to validate these atomic write limit fields.
> The test ensures the filesystem correctly advertises the STATX_ATTR_WRITE_ATOMIC
> attribute when queried on a file opened with O_DIRECT. It also verifies that the
> reported optimized maximum is logically consistent by falling within the
> absolute minimum and maximum boundaries. Furthermore, it checks that all
> reported atomic write unit sizes are valid powers of two, adhering to the strict
> requirements of the kernel block layer.

> If the underlying storage hardware or filesystem lacks atomic write
> support, the test gracefully skips with TCONF.

> Fixes: #1224
...
> 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
...
> +#ifdef HAVE_STRUCT_STATX_STX_ATOMIC_WRITE_UNIT_MAX_OPT
Looking at this, I wonder why this and also older statx10.c, statx11.c does not
use ltp_statx added by Andrea in d89a232a7b ("Add SAFE_STATX macro")

Kind regards,
Petr

> +	if (buff.stx_atomic_write_unit_max_opt == 0) {
> +		tst_res(TINFO, "stx_atomic_write_unit_max_opt is 0 (no optimized max reported)");
> +	} else {
> +		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)
> +			tst_res(TFAIL, "stx_atomic_write_unit_max_opt (%u) is less than min (%u)",
> +					buff.stx_atomic_write_unit_max_opt,
> +					buff.stx_atomic_write_unit_min);
> +		else
> +			tst_res(TPASS, "stx_atomic_write_unit_max_opt (%u) is within valid range [%u, %u]",
> +					buff.stx_atomic_write_unit_max_opt,
> +					buff.stx_atomic_write_unit_min,
> +					buff.stx_atomic_write_unit_max);
> +
> +		if (__builtin_popcount(buff.stx_atomic_write_unit_max_opt) != 1)
> +			tst_res(TFAIL, "stx_atomic_write_unit_max_opt (%u) is not a power of 2",
> +					buff.stx_atomic_write_unit_max_opt);
> +	}
> +#else
> +	tst_res(TCONF, "stx_atomic_write_unit_max_opt is not defined in struct statx");
> +#endif
> +}