Re: [PATCH] generic/4[13,62]: restore TEST mount options

Eryu Guan
2017-11-02T12:13:25Z

On Wed, Nov 01, 2017 at 05:03:21PM +0200, Omer Zilberberg wrote:
>
>
> On 11/01/2017 02:52 PM, Eryu Guan wrote:
> > On Wed, Nov 01, 2017 at 02:06:27PM +0200, Omer Zilberberg wrote:
> >>
> >> On 10/31/2017 01:34 PM, Eryu Guan wrote:
> >>> On Tue, Oct 31, 2017 at 12:25:51PM +0200, Omer Zilberberg wrote:
> >>>> On 10/31/2017 06:37 AM, Eryu Guan wrote:
> >>>>> On Tue, Oct 31, 2017 at 07:36:58AM +1100, Dave Chinner wrote:
> >>>>>> On Mon, Oct 30, 2017 at 10:08:31AM +0200, Omer Zilberberg wrote:
> >>>>>>> These tests locally change the TEST_FS_MOUNT_OPTS/MOUNT_OPTIONS
> >>>>>>> environment variables, and run _test_cycle_mount. As a result, following
> >>>>>>> tests using the TEST mount point may start with different mount options,
> >>>>>>> depending on run order.
> >>>>>> I don't think that's the case. The change of the environment
> >>>>>> variable should only affect the current test process and it's
> >>>>>> children. When the test exits, we go back to the environment of the
> >>>>>> check process, where the TEST_FS_MOUNT_OPTS environment variable is
> >>>>>> still correctly set, and all future tests inherit from that. i.e.:
> >>>>>>
> >>>>>> $ export FOO=foo
> >>>>>> $ echo $FOO
> >>>>>> foo
> >>>>>> $ bash
> >>>>>> $ echo $FOO
> >>>>>> foo
> >>>>>> $ export FOO=bar
> >>>>>> $ echo $FOO
> >>>>>> bar
> >>>>>> $ exit
> >>>>>> $ echo $FOO
> >>>>>> foo
> >>>>>> $
> >>>>>>
> >>>>>> And after each test, check runs _check_filesystems(), which cycles
> >>>>>> the test mount, so for each new test process that is run they should
> >>>>>> already start in the correct state...
> >>>>> I agreed, the changing of variables in a sub-shell won't affect the
> >>>>> parent's copy, and check will restore the mounts with the untouched
> >>>>> options.
> >>>>>
> >>>>> But the problem is that _check_test_fs() will cycle mount TEST_DEV with
> >>>>> MOUNT_OPTIONS not TEST_FS_MOUNT_OPTS, so if you have different mount
> >>>>> options set for TEST_DEV and SCRATCH_DEV, you'll see mount options
> >>>>> changed for TEST_DEV. e.g.
> >>>>>
> >>>>> MOUNT_OPTIONS="-o dax" TEST_FS_MOUNT_OPTS="" ./check generic/413 generic/445
> >>>>> generic/445 mount TEST_DEV with "-o dax" too
> >>>>>
> >>>>> MOUNT_OPTIONS="" TEST_FS_MOUNT_OPTS="-o dax" ./check generic/413 generic/445
> >>>>> generic/445 mount TEST_DEV without "-o dax"
> >>>>>
> >>>>> MOUNT_OPTIONS="-o dax" TEST_FS_MOUNT_OPTS="-o dax" ./check generic/413 generic/445
> >>>>> both tests and both devices mount with "-o dax"
> >>>>>
> >>>>> That's been discussed in this thread:
> >>>>> https://patchwork.kernel.org/patch/9742039/
> >>>>>
> >>>>> Omer, can you please confirm if you're hitting this issue?
> >>>> I'm not 100% that's the case, so I better describe my settings more clearly:
> >>>> I have a debug mount option on my system to recover the FS from a backup.
> >>>> When that flag is set, umount writes everything to the backup.
> >>>> Mount restores from it, overwriting everything.
> >>> If you're testing with setting your debug mount option to both
> >>> TEST_FS_MOUNT_OPTS and MOUNT_OPTIONS, and you still see the failure you
> >>> were seeing, then that's a different problem.
> >> Yeah, that's what I'm doing, setting both with that flag.
> >>>> As long as generic/413 is not involved, everything works well.
> >>>> All _test_cycle_mount() calls first back everything up on umount,
> >>>> then restore upon mount. So I get the same FS contents.
> >>>>
> >>>> But, consider generic/118 running after generic/413:
> >>>> - generic/413 finishes with a mount point with no mount options
> >>>> - generic/118 begins with restored TEST_FS_MOUNT_OPTS, as you've pointed out.
> >>>> - some writes are performed to the FS
> >>>> - next _test_cycle_mount:
> >>>>   calls umount w/o backing up (debug flag previously unset by generic/413).
> >>> Does this clear the backup too? If so, I suspect TEST_DEV got cleared on
> >>> first mount with the debug option in generic/118, because the backup has
> >>> been cleared in the _test_cycle_mount call in generic/413.
> >> Yeah the backup is cleared, which is normal behavior when the debug flag is off.
> >> And exactly, it's generic/413 clearing the flag from the mount point,
> >> that's caused this.
> > IMHO, in this case fstests doesn't do anything wrong, all the mount
> > options are restored when running the next test, it's just not
> > compatible with your debug option and workflow.
> But the mount options are not restored when running the next test...
> Only the first _test_cycle_mount restores them.
> In case I haven't made myself clear, here's a final demonstration.
> If you still think this is valid, I'll back down :)
>
> I've edited generic/118 locally, and after _require_test_reflink, I've added:
> mount | grep $TEST_DIR
> Just to see the mount options the TEST FS has.
>
> I've also put aside my debug option, and used -o strictatime instead.
> If I mount w/o special options, I get the "relatime" mount option as default.
> If I mount with -o strictatime, I do not see "relatime". Now back to fstests:

I assume you still set "-o strictatime" to both TEST_FS_MOUNT_OPTS and
MOUNT_OPTIONS, so all went well so far.

>
> If the order of run is generic/118 followed by generic/413,
> Then generic/118 does NOT print "relatime" in its options, because strictatime
> is active.

Yeah, I saw the same result, which was also expected.

> However, if the order of run is reversed, then "relatime" IS printed, because
> the TEST FS' was left with default mount options by generic/413.

I saw different result here, generic/118 didn't print relatime for me.

[root@ibm-x3550m3-05 xfstests]# TEST_FS_MOUNT_OPTS="-o strictatime" MOUNT_OPTIONS="-o strictatime" ./check generic/413 generic/118
FSTYP -- xfs (debug)
PLATFORM -- Linux/x86_64 ibm-x3550m3-05 4.14.0-rc7
MKFS_OPTIONS -- -f -bsize=4096 /dev/sdc2
MOUNT_OPTIONS -- -o strictatime /dev/sdc2 /mnt/testarea/scratch

generic/413 1s ... - output mismatch (see /root/xfstests/results//generic/413.out.bad)
--- tests/generic/413.out 2017-10-11 18:15:46.720424655 +0800
+++ /root/xfstests/results//generic/413.out.bad 2017-11-02 20:02:39.546307209 +0800
@@ -1,2 +1,4 @@
QA output created by 413
+/dev/sdc1 on /mnt/testarea/test type xfs (rw,seclabel,attr2,inode64,noquota) # right after _require_test
+/dev/sdc1 on /mnt/testarea/test type xfs (rw,relatime,attr2,inode64,noquota) # after _cycle_test_mount
Silence is golden
...
(Run 'diff -u tests/generic/413.out /root/xfstests/results//generic/413.out.bad' to see the entire diff)
generic/118 0s ... - output mismatch (see /root/xfstests/results//generic/118.out.bad)
--- tests/generic/118.out 2017-10-11 18:15:46.644423183 +0800
+++ /root/xfstests/results//generic/118.out.bad 2017-11-02 20:02:41.080336481 +0800
@@ -1,5 +1,7 @@
QA output created by 118
+/dev/sdc1 on /mnt/testarea/test type xfs (rw,seclabel,attr2,inode64,noquota) # right after _require_test_reflink
Create the original files
+/dev/sdc1 on /mnt/testarea/test type xfs (rw,attr2,inode64,noquota) # after _cycle_test_mount

Note that I hacked 'check' too to not sort the tests by seq number.

Did I miss anything?

Thanks,
Eryu

>
> So, generic/118's start conditions depend on its predecessor.
> Is that valid for TEST fs mount options?
>
> >
> >>>>   calls mount WITH the debug flag, and recovers from an empty backup,
> >>>>   deleting the earlier writes.
> >>>> - subsequent md5sum fails on "No such file or directory", as FS is now empty.
> >>>>
> >>>>> I think fixing _check_<fs>_filesystem() is the correct way. And I guess
> >>>>> we can refactor out a common function and call it in
> >>>>> _check_[xfs|btrfs|generic]_filesystem, pass the correct mount options
> >>>>> based on what device we're working on.
> >>>> If indeed we're talking about the same problem,
> >>>> please let me know if you'd like me to prepare a different patch.
> >>> Sure, really appreciated if you can prepare a different patch, even if
> >>> it's not the same problem :)
> >> Ok.
> >> But are we in agreement that there are 2 different issues here?
> > Yes, the problem you hit is different with the issue I described above.
> >
> >> If so, please let me know what you think of this patch,
> >> which does resolve that issue I had originally (at least locally for me).
> > I prefer not merging your patch, sorry. Because in this specific case,
> > from fstests' point of view, it's all doing well and everything works as
> > expected.
> >
> >> And I'll explore the issue with check_test_fs and the different mount options,
> >> based on what you've both written here and the thread you've pointed to.
> >> I'll send another patch to address that later.
> > Thanks a lot!
> >
> > Eryu
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