[LTP] [PATCH] unshare01.sh: Setup parent mount flag before unshare testing

[zhaogongyi]

Hi Yang,

> I don't like the approach which enforces mountpoint to be shared in
> parent mount namespace.
> I think we can tune expected value by checking propagation flag in parent
> mount namespace because of two reasons:
> 1) Make test cover more cases.
> 2) Don't depend on the fixed tmpfs.


If we have no fixed parent mount namespace, the test looks like will pass at any cases since we judge result by "grep -w 'dir_B' /proc/self/mountinfo | grep -qw 'shared'".

It seems a bit tangential to our test objective as " # 6) If we run with "--mount --propagation shared", mount and unmount events propagate to its parent mount namespace. "


Thanks!

==========================================================

> 
> Hi Zhongyi, Petr
> 
> I don't like the approach which enforces mountpoint to be shared in
> parent mount namespace.
> I think we can tune expected value by checking propagation flag in parent
> mount namespace because of two reasons:
> 1) Make test cover more cases.
> 2) Don't depend on the fixed tmpfs.
> 
> Zhongyi,  could you test the following patch on your enviorment?
> -------------------------------------------------------------------------------------------------
> diff --git a/testcases/commands/unshare/unshare01.sh
> b/testcases/commands/unshare/unshare01.sh
> index bf163a7f4..78ea83fc0 100755
> --- a/testcases/commands/unshare/unshare01.sh
> +++ b/testcases/commands/unshare/unshare01.sh
> @@ -40,6 +40,17 @@
> max_mntns_path="/proc/sys/user/max_mnt_namespaces"
>   default_max_userns=-1
>   default_max_mntns=-1
> 
> +parse_propagation_flag()
> +{
> +       mount --bind dir_A dir_B
> +       if grep -w 'dir_B' /proc/self/mountinfo | grep -qw 'shared'; then
> +               echo "mounted"
> +       else
> +               echo "unmounted"
> +       fi
> +       umount dir_B
> +}
> +
>   setup()
>   {
>          # On some distributions(e.g RHEL7.4), the default value of @@
> -149,7 +160,8 @@ do_test()
>          4) unshare_test "--user --map-root-user" "id -g" "0";;
>          5) unshare_test "--mount" "mount --bind dir_A dir_B"
> "unmounted";;
>          6) unshare_test "--mount --propagation shared" \
> -                       "mount --bind dir_A dir_B" "mounted";;
> +                       "mount --bind dir_A dir_B" \
> +                       "$(parse_propagation_flag)";;
>          7) unshare_test "--user --map-root-user --mount" \
>                          "mount --bind dir_A dir_B" "unmounted";;
>          8) unshare_test "--user --map-root-user --mount --propagation
> shared" \
> --
> ------------------------------------------------------------------------------------------
> 
> Best Regards,
> Xiao Yang
> On 2021/2/24 9:40, Petr Vorel wrote:
> > Hi,
> >
> >> We need setup parent mount flag to shared before unshare testing, or
> >> it will fail for system which has no systemd service since the
> >> propagation flag is changed by systemd. From man 7
> mount_namespaces.
> > Do I understand correctly that all distros without systemd are
> > affected, because systemd "automatically remounts all mount points as
> > MS_SHARED on system startup" and test expect it?
> >
> >> Signed-off-by: Zhao Gongyi<zhaogongyi@huawei.com>
> >> ---
> >>   testcases/commands/unshare/unshare01.sh | 9 ++++++++-
> >>   1 file changed, 8 insertions(+), 1 deletion(-) diff --git
> >> a/testcases/commands/unshare/unshare01.sh
> >> b/testcases/commands/unshare/unshare01.sh
> >> index bf163a7f4..e1fb15035 100755
> >> --- a/testcases/commands/unshare/unshare01.sh
> >> +++ b/testcases/commands/unshare/unshare01.sh
> >> @@ -31,7 +31,6 @@ TST_SETUP=setup
> >>   TST_CLEANUP=cleanup
> >>   TST_TESTFUNC=do_test
> >>   TST_NEEDS_ROOT=1
> >> -TST_NEEDS_TMPDIR=1
> > You still need TST_NEEDS_TMPDIR=1, because you create files and
> directories.
> >
> > Also your patch breaks bind test on very old systems (kernel 2.6,
> > util-linux 2.17.2, glibc 2.12):
> > unshare01 5 TFAIL: unshare --mount mount --bind dir_A dir_B got bind
> > info
> >
> > Any idea why (how to avoid this regression)?
> >
> >>   TST_NEEDS_CMDS="unshare id mount umount"
> >>   . tst_test.sh
> >> @@ -39,6 +38,7 @@
> max_userns_path="/proc/sys/user/max_user_namespaces"
> >>   max_mntns_path="/proc/sys/user/max_mnt_namespaces"
> >>   default_max_userns=-1
> >>   default_max_mntns=-1
> >> +CURR=$(pwd)
> > Instead of $CURR, cd - can be used.
> >
> >>   setup()
> >>   {
> >> @@ -55,6 +55,10 @@ setup()
> >>   		echo 1024>  "${max_mntns_path}"
> >>   	fi
> >> +	mkdir $CURR/dir_C
> > just mkdir dir_C
> >> +	mount -t tmpfs none dir_C
> >> +	mount --make-shared dir_C
> > FYI We have tst_mount, but it'd not help much here.
> >
> >> +	cd dir_C
> >>   	mkdir -p dir_A dir_B
> >>   	touch dir_A/A dir_B/B
> >>   }
> >> @@ -66,6 +70,9 @@ cleanup()
> >>   		echo ${default_max_userns}>  "${max_userns_path}"
> >>   	[ ${default_max_mntns} -ne -1 ]&&  \
> >>   		echo ${default_max_mntns}>  "${max_mntns_path}"
> >> +	cd $CURR
> >> +	umount dir_C
> > tst_umount dir_C
> >
> >> +	rm -rf dir_C
> > rm is not needed (cleanup is done automatically).
> >>   }
> >>   check_id()
> > Full diff of changes I propose below.
> >
> > Kind regards,
> > Petr
> >
> > diff --git testcases/commands/unshare/unshare01.sh
> > testcases/commands/unshare/unshare01.sh
> > index e1fb15035..0b5c56811 100755
> > --- testcases/commands/unshare/unshare01.sh
> > +++ testcases/commands/unshare/unshare01.sh
> > @@ -31,6 +31,7 @@ TST_SETUP=setup
> >   TST_CLEANUP=cleanup
> >   TST_TESTFUNC=do_test
> >   TST_NEEDS_ROOT=1
> > +TST_NEEDS_TMPDIR=1
> >   TST_NEEDS_CMDS="unshare id mount umount"
> >   . tst_test.sh
> >
> > @@ -38,7 +39,6 @@
> max_userns_path="/proc/sys/user/max_user_namespaces"
> >   max_mntns_path="/proc/sys/user/max_mnt_namespaces"
> >   default_max_userns=-1
> >   default_max_mntns=-1
> > -CURR=$(pwd)
> >
> >   setup()
> >   {
> > @@ -55,7 +55,7 @@ setup()
> >   		echo 1024>  "${max_mntns_path}"
> >   	fi
> >
> > -	mkdir $CURR/dir_C
> > +	mkdir dir_C
> >   	mount -t tmpfs none dir_C
> >   	mount --make-shared dir_C
> >   	cd dir_C
> > @@ -70,9 +70,8 @@ cleanup()
> >   		echo ${default_max_userns}>  "${max_userns_path}"
> >   	[ ${default_max_mntns} -ne -1 ]&&  \
> >   		echo ${default_max_mntns}>  "${max_mntns_path}"
> > -	cd $CURR
> > -	umount dir_C
> > -	rm -rf dir_C
> > +	cd ->/dev/null
> > +	tst_umount dir_C
> >   }
> >
> >   check_id()
> >
> 
>