S390: Don't test nanoseconds in io/tst-stat.c
Commit Message
Both new tests io/tst-stat and io/tst-stat-lfs (_FILE_OFFSET_BITS=64)
are comparing the nanosecond fields with the statx result. Unfortunately
on s390(31bit) those fields are always zero if old KABI with non-LFS
support is used. With _FILE_OFFSET_BITS=64 stat is using statx internally.
As suggested by Adhemerval this patch disables the nanosecond check for
s390(31bit).
---
io/tst-stat.c | 7 +++++--
support/Makefile | 1 +
support/support.h | 3 +++
support/support_stat_nanoseconds.c | 31 ++++++++++++++++++++++++++++++
4 files changed, 40 insertions(+), 2 deletions(-)
create mode 100644 support/support_stat_nanoseconds.c
Comments
On Wed, 17 Mar 2021, Stefan Liebler via Libc-alpha wrote:
> Both new tests io/tst-stat and io/tst-stat-lfs (_FILE_OFFSET_BITS=64)
> are comparing the nanosecond fields with the statx result. Unfortunately
> on s390(31bit) those fields are always zero if old KABI with non-LFS
> support is used. With _FILE_OFFSET_BITS=64 stat is using statx internally.
My understanding is that, if using a kernel that supports statx, this
disabling is not needed.
If so, we want to be sure to remove this disabling once we can assume a
kernel supporting statx (on s390). The way we ensure that is having a
conditional on __ASSUME_STATX in the code in question so that it's
immediately visible when we remove __ASSUME_STATX that this disabling can
be removed from the glibc source code as well.
On 17/03/2021 18:01, Joseph Myers wrote:
> On Wed, 17 Mar 2021, Stefan Liebler via Libc-alpha wrote:
>
>> Both new tests io/tst-stat and io/tst-stat-lfs (_FILE_OFFSET_BITS=64)
>> are comparing the nanosecond fields with the statx result. Unfortunately
>> on s390(31bit) those fields are always zero if old KABI with non-LFS
>> support is used. With _FILE_OFFSET_BITS=64 stat is using statx internally.
>
> My understanding is that, if using a kernel that supports statx, this
> disabling is not needed.
The non-LFS stat does not call statx, so the nanoseconds call should be
disable only for non-LFS mode.
>
> If so, we want to be sure to remove this disabling once we can assume a
> kernel supporting statx (on s390). The way we ensure that is having a
> conditional on __ASSUME_STATX in the code in question so that it's
> immediately visible when we remove __ASSUME_STATX that this disabling can
> be removed from the glibc source code as well.
>
On 17/03/2021 10:03, Stefan Liebler wrote:
> Both new tests io/tst-stat and io/tst-stat-lfs (_FILE_OFFSET_BITS=64)
> are comparing the nanosecond fields with the statx result. Unfortunately
> on s390(31bit) those fields are always zero if old KABI with non-LFS
> support is used. With _FILE_OFFSET_BITS=64 stat is using statx internally.
>
> As suggested by Adhemerval this patch disables the nanosecond check for
> s390(31bit).
LGTM, the fstatat call does not call statx and even for LFS that call statx
it might ended calling old stat syscall in the fallback part that does not
About the __ASSUME_STATX note Joseph has raised, I think we should add it
on Linux at least for fstatat64 implementation. However it does not really
help on the fstatat one. I will try to spare some time to make fstatat.c
use statx as well, so we can tie the test to __ASSUME_STATX.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
> ---
> io/tst-stat.c | 7 +++++--
> support/Makefile | 1 +
> support/support.h | 3 +++
> support/support_stat_nanoseconds.c | 31 ++++++++++++++++++++++++++++++
> 4 files changed, 40 insertions(+), 2 deletions(-)
> create mode 100644 support/support_stat_nanoseconds.c
>
> diff --git a/io/tst-stat.c b/io/tst-stat.c
> index 445ac4176c..397d480ecc 100644
> --- a/io/tst-stat.c
> +++ b/io/tst-stat.c
> @@ -91,9 +91,12 @@ do_test (void)
> TEST_COMPARE (stx.stx_blocks, st.st_blocks);
>
> TEST_COMPARE (stx.stx_ctime.tv_sec, st.st_ctim.tv_sec);
> - TEST_COMPARE (stx.stx_ctime.tv_nsec, st.st_ctim.tv_nsec);
> TEST_COMPARE (stx.stx_mtime.tv_sec, st.st_mtim.tv_sec);
> - TEST_COMPARE (stx.stx_mtime.tv_nsec, st.st_mtim.tv_nsec);
> + if (support_stat_nanoseconds ())
> + {
> + TEST_COMPARE (stx.stx_ctime.tv_nsec, st.st_ctim.tv_nsec);
> + TEST_COMPARE (stx.stx_mtime.tv_nsec, st.st_mtim.tv_nsec);
> + }
> }
>
> return 0;
> diff --git a/support/Makefile b/support/Makefile
> index fc9f4936a8..900e17f94f 100644
> --- a/support/Makefile
> +++ b/support/Makefile
> @@ -71,6 +71,7 @@ libsupport-routines = \
> support_set_small_thread_stack_size \
> support_shared_allocate \
> support_small_stack_thread_attribute \
> + support_stat_nanoseconds \
> support_subprocess \
> support_test_compare_blob \
> support_test_compare_failure \
> diff --git a/support/support.h b/support/support.h
> index 2e477c9e7c..90f3ff9d1a 100644
> --- a/support/support.h
> +++ b/support/support.h
> @@ -134,6 +134,9 @@ extern ssize_t support_copy_file_range (int, off64_t *, int, off64_t *,
> operations (such as fstatat or utimensat). */
> extern bool support_path_support_time64 (const char *path);
>
> +/* Return true if stat supports nanoseconds resolution. */
> +extern bool support_stat_nanoseconds (void);
> +
> __END_DECLS
>
> #endif /* SUPPORT_H */
> diff --git a/support/support_stat_nanoseconds.c b/support/support_stat_nanoseconds.c
> new file mode 100644
> index 0000000000..c0d5b2c3a9
> --- /dev/null
> +++ b/support/support_stat_nanoseconds.c
> @@ -0,0 +1,31 @@
> +/* Check if stat supports nanosecond resolution.
> + Copyright (C) 2021 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <https://www.gnu.org/licenses/>. */
> +
> +#include <stdbool.h>
> +
> +bool
> +support_stat_nanoseconds (void)
> +{
> + /* s390 stat64 compat symbol does not support nanoseconds resolution
> + and it used on non-LFS [f,l]stat[at] implementations. */
> +#if defined __linux__ && !defined __s390x__ && defined __s390__
> + return false;
> +#else
> + return true;
> +#endif
> +}
>
On 18/03/2021 14:31, Adhemerval Zanella wrote:
>
>
> On 17/03/2021 10:03, Stefan Liebler wrote:
>> Both new tests io/tst-stat and io/tst-stat-lfs (_FILE_OFFSET_BITS=64)
>> are comparing the nanosecond fields with the statx result. Unfortunately
>> on s390(31bit) those fields are always zero if old KABI with non-LFS
>> support is used. With _FILE_OFFSET_BITS=64 stat is using statx internally.
>>
>> As suggested by Adhemerval this patch disables the nanosecond check for
>> s390(31bit).
>
> LGTM, the fstatat call does not call statx and even for LFS that call statx
> it might ended calling old stat syscall in the fallback part that does not
>
> About the __ASSUME_STATX note Joseph has raised, I think we should add it
> on Linux at least for fstatat64 implementation. However it does not really
> help on the fstatat one. I will try to spare some time to make fstatat.c
> use statx as well, so we can tie the test to __ASSUME_STATX.
>
> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
>
Hi Adhemerval,
Sorry for the delay, I was busy with another project.
Thanks for your series
"[PATCH 1/5] linux: Implement fstatat with __fstatat64_time64"
https://sourceware.org/pipermail/libc-alpha/2021-March/124191.html
As also mentioned there, with your series, at least on my s390 systems,
stat is then using statx and the nanosecond fields are not zero anymore.
Shall I commit my patch as is and as soon as you've commited your
series, you can adjust support_stat_nanoseconds to return false if
__ASSUME_STATX is not defined?
Thanks,
Stefan
On 23/03/2021 13:13, Stefan Liebler wrote:
> On 18/03/2021 14:31, Adhemerval Zanella wrote:
>>
>>
>> On 17/03/2021 10:03, Stefan Liebler wrote:
>>> Both new tests io/tst-stat and io/tst-stat-lfs (_FILE_OFFSET_BITS=64)
>>> are comparing the nanosecond fields with the statx result. Unfortunately
>>> on s390(31bit) those fields are always zero if old KABI with non-LFS
>>> support is used. With _FILE_OFFSET_BITS=64 stat is using statx internally.
>>>
>>> As suggested by Adhemerval this patch disables the nanosecond check for
>>> s390(31bit).
>>
>> LGTM, the fstatat call does not call statx and even for LFS that call statx
>> it might ended calling old stat syscall in the fallback part that does not
>>
>> About the __ASSUME_STATX note Joseph has raised, I think we should add it
>> on Linux at least for fstatat64 implementation. However it does not really
>> help on the fstatat one. I will try to spare some time to make fstatat.c
>> use statx as well, so we can tie the test to __ASSUME_STATX.
>>
>> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
>>
>
> Hi Adhemerval,
>
> Sorry for the delay, I was busy with another project.
> Thanks for your series
> "[PATCH 1/5] linux: Implement fstatat with __fstatat64_time64"
> https://sourceware.org/pipermail/libc-alpha/2021-March/124191.html
>
> As also mentioned there, with your series, at least on my s390 systems,
> stat is then using statx and the nanosecond fields are not zero anymore.
>
> Shall I commit my patch as is and as soon as you've commited your
> series, you can adjust support_stat_nanoseconds to return false if
> __ASSUME_STATX is not defined?
Yes, I can rebase on top your patch. I think we still need to handle
the nanosecond missing support on older kernels.
Thanks for checking on s390, if you can review the patchset I would be
grateful
On 24/03/2021 18:40, Adhemerval Zanella wrote:
>
>
> On 23/03/2021 13:13, Stefan Liebler wrote:
>> On 18/03/2021 14:31, Adhemerval Zanella wrote:
>>>
>>>
>>> On 17/03/2021 10:03, Stefan Liebler wrote:
>>>> Both new tests io/tst-stat and io/tst-stat-lfs (_FILE_OFFSET_BITS=64)
>>>> are comparing the nanosecond fields with the statx result. Unfortunately
>>>> on s390(31bit) those fields are always zero if old KABI with non-LFS
>>>> support is used. With _FILE_OFFSET_BITS=64 stat is using statx internally.
>>>>
>>>> As suggested by Adhemerval this patch disables the nanosecond check for
>>>> s390(31bit).
>>>
>>> LGTM, the fstatat call does not call statx and even for LFS that call statx
>>> it might ended calling old stat syscall in the fallback part that does not
>>>
>>> About the __ASSUME_STATX note Joseph has raised, I think we should add it
>>> on Linux at least for fstatat64 implementation. However it does not really
>>> help on the fstatat one. I will try to spare some time to make fstatat.c
>>> use statx as well, so we can tie the test to __ASSUME_STATX.
>>>
>>> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
>>>
>>
>> Hi Adhemerval,
>>
>> Sorry for the delay, I was busy with another project.
>> Thanks for your series
>> "[PATCH 1/5] linux: Implement fstatat with __fstatat64_time64"
>> https://sourceware.org/pipermail/libc-alpha/2021-March/124191.html
>>
>> As also mentioned there, with your series, at least on my s390 systems,
>> stat is then using statx and the nanosecond fields are not zero anymore.
>>
>> Shall I commit my patch as is and as soon as you've commited your
>> series, you can adjust support_stat_nanoseconds to return false if
>> __ASSUME_STATX is not defined?
>
> Yes, I can rebase on top your patch. I think we still need to handle
> the nanosecond missing support on older kernels.
I've just committed this patch.
>
> Thanks for checking on s390, if you can review the patchset I would be
> grateful
Sure. I've left some comments
Thanks,
Stefan
@@ -91,9 +91,12 @@ do_test (void)
TEST_COMPARE (stx.stx_blocks, st.st_blocks);
TEST_COMPARE (stx.stx_ctime.tv_sec, st.st_ctim.tv_sec);
- TEST_COMPARE (stx.stx_ctime.tv_nsec, st.st_ctim.tv_nsec);
TEST_COMPARE (stx.stx_mtime.tv_sec, st.st_mtim.tv_sec);
- TEST_COMPARE (stx.stx_mtime.tv_nsec, st.st_mtim.tv_nsec);
+ if (support_stat_nanoseconds ())
+ {
+ TEST_COMPARE (stx.stx_ctime.tv_nsec, st.st_ctim.tv_nsec);
+ TEST_COMPARE (stx.stx_mtime.tv_nsec, st.st_mtim.tv_nsec);
+ }
}
return 0;
@@ -71,6 +71,7 @@ libsupport-routines = \
support_set_small_thread_stack_size \
support_shared_allocate \
support_small_stack_thread_attribute \
+ support_stat_nanoseconds \
support_subprocess \
support_test_compare_blob \
support_test_compare_failure \
@@ -134,6 +134,9 @@ extern ssize_t support_copy_file_range (int, off64_t *, int, off64_t *,
operations (such as fstatat or utimensat). */
extern bool support_path_support_time64 (const char *path);
+/* Return true if stat supports nanoseconds resolution. */
+extern bool support_stat_nanoseconds (void);
+
__END_DECLS
#endif /* SUPPORT_H */
new file mode 100644
@@ -0,0 +1,31 @@
+/* Check if stat supports nanosecond resolution.
+ Copyright (C) 2021 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#include <stdbool.h>
+
+bool
+support_stat_nanoseconds (void)
+{
+ /* s390 stat64 compat symbol does not support nanoseconds resolution
+ and it used on non-LFS [f,l]stat[at] implementations. */
+#if defined __linux__ && !defined __s390x__ && defined __s390__
+ return false;
+#else
+ return true;
+#endif
+}