[LTP] [PATCH] Fix mountns01/02/03/04 removing unneeded final umounts

[xuyang2018.jy@fujitsu.com]

Hi  Cristian

> Running LTP20220527 release it appears that the recently re-written tests
> mountns02/03/04 now throw a warning on their final umount attempt:
>
> <<<test_output>>>
> tst_test.c:1526: TINFO: Timeout per run is 0h 00m 30s
> mountns04.c:38: TPASS: unbindable mount passed
> tst_device.c:395: TWARN: umount('A') failed with EINVAL
> mountns.h:36: TWARN: umount(A) failed: EINVAL (22)
> tst_device.c:434: TINFO: No device is mounted at B

I guess this failure because /proc/mounts still has "A", so 
tst_is_mounted returns true and umount failed.

we can reproduce it by using a /mnt/A mntpoint in /proc/mounts.
>
> Moreover, the underlying safe_umount() then upgrades the TWARN emitted
> from tst_umount to a TBROK, so causing the test to completely fail:
>
> Summary:
> passed   1
> failed   0
> broken   0
> skipped  0
> warnings 2
> <<<execution_status>>>
> initiation_status="ok"
> duration=0 termination_type=exited termination_id=4 corefile=no
>
> In fact, the final umounts on DIRA seem not needed in mountns02/03/04
> looking at the previous chain of umounts calls and the tests logic and,
> in any case, the .cleanup functions of all these tests take care to
> finally unmount both DIRA/DIRB after having checked if they were still
> mounted at all.
>
> Remove all the final SAFE_UMOUNT calls (even for mountns01) since all the
> possibly needed umounts are already eventually performed by .cleanup.

Yes, it can fix this problem but these case still will fail when 
/proc/mounts has a B mntpoint,

ie
  mount /dev/sda11 /mnt/B
./mountns04
tst_test.c:1528: TINFO: Timeout per run is 0h 00m 30s
mountns04.c:38: TPASS: unbindable mount passed
tst_device.c:395: TWARN: umount('B') failed with EINVAL
mountns.h:39: TWARN: umount(B) failed: EINVAL (22)

So I think a right fix should fix the tst_is_mounted function or 
umount_folders instead of removing final SAFE_UMOUNT.


Best Regards
Yang Xu

>
> Cc: Andrea Cervesato<andrea.cervesato@suse.de>
> Cc: Cyril Hrubis<chrubis@suse.cz>
> Signed-off-by: Cristian Marussi<cristian.marussi@arm.com>
> ---
>   testcases/kernel/containers/mountns/mountns01.c | 2 --
>   testcases/kernel/containers/mountns/mountns02.c | 2 --
>   testcases/kernel/containers/mountns/mountns03.c | 2 --
>   testcases/kernel/containers/mountns/mountns04.c | 2 --
>   4 files changed, 8 deletions(-)
>
> diff --git a/testcases/kernel/containers/mountns/mountns01.c b/testcases/kernel/containers/mountns/mountns01.c
> index 452fe1d10..7c9461e4d 100644
> --- a/testcases/kernel/containers/mountns/mountns01.c
> +++ b/testcases/kernel/containers/mountns/mountns01.c
> @@ -85,8 +85,6 @@ static void run(void)
>   		tst_res(TFAIL, "shared mount in child failed");
>
>   	TST_CHECKPOINT_WAKE(0);
> -
> -	SAFE_UMOUNT(DIRA);
>   }
>
>   static void setup(void)
> diff --git a/testcases/kernel/containers/mountns/mountns02.c b/testcases/kernel/containers/mountns/mountns02.c
> index cbd435958..0693bb9f6 100644
> --- a/testcases/kernel/containers/mountns/mountns02.c
> +++ b/testcases/kernel/containers/mountns/mountns02.c
> @@ -86,8 +86,6 @@ static void run(void)
>   		tst_res(TPASS, "private mount in child passed");
>
>   	TST_CHECKPOINT_WAKE(0);
> -
> -	SAFE_UMOUNT(DIRA);
>   }
>
>   static void setup(void)
> diff --git a/testcases/kernel/containers/mountns/mountns03.c b/testcases/kernel/containers/mountns/mountns03.c
> index 5c19a96a9..aceab32ae 100644
> --- a/testcases/kernel/containers/mountns/mountns03.c
> +++ b/testcases/kernel/containers/mountns/mountns03.c
> @@ -96,8 +96,6 @@ static void run(void)
>   		tst_res(TFAIL, "propagation form slave mount failed");
>
>   	TST_CHECKPOINT_WAKE(0);
> -
> -	SAFE_UMOUNT(DIRA);
>   }
>
>   static void setup(void)
> diff --git a/testcases/kernel/containers/mountns/mountns04.c b/testcases/kernel/containers/mountns/mountns04.c
> index cc63a03d9..d0ecf7667 100644
> --- a/testcases/kernel/containers/mountns/mountns04.c
> +++ b/testcases/kernel/containers/mountns/mountns04.c
> @@ -40,8 +40,6 @@ static void run(void)
>   		SAFE_UMOUNT(DIRB);
>   		tst_res(TFAIL, "unbindable mount faled");
>   	}
> -
> -	SAFE_UMOUNT(DIRA);
>   }
>
>   static void setup(void)