[dm-devel] reinstate path not working
Tejaswini Poluri
tejaswinipoluri3 at gmail.com
Fri Jun 26 06:51:48 UTC 2015
Yes I agree that having the same code in both cli_add_map() and ev_add_map
is not necessary. Hence I would suggest removing get_refwwid() code from
ev_add_map as it is not being used by anyone.
ev_add_map(param, NULL, vecs) would create the multipath device by using
the get_refwwid() code and but all the functions above it like
(dm_get_minor, dm_get_major and dm_mapname) would fail and it wouldn't
enter any of the other code in ev_add_map like
1.dm_map_present,
2.add_map_without_path
3. sync_map_state
which are responsible for registering the map and displaying it.
So, I think moving the below code from ev_add_map to cli_add_map should be
a good idea right.
r = get_refwwid(dev, DEV_DEVMAP, vecs->pathvec,&refwwid);
>
> if (refwwid) {
> r = coalesce_paths(vecs, NULL, refwwid,0);
> dm_lib_release();
> }
What do u think?
Regards,
Tejaswini
On Fri, Jun 26, 2015 at 4:32 AM, Benjamin Marzinski <bmarzins at redhat.com>
wrote:
> On Tue, Jun 23, 2015 at 03:48:26PM +0530, Tejaswini Poluri wrote:
> > Hi Ben,
> >
> > This is regarding the add map issue I have been discussing. Posting
> the
> > issue again to remind.
> >
> > Case 1 : remove and add map.
> > root at x86-generic-64:~# multipathd -k'show maps'
> > name sysfs uuid
> > dmpath0 dm-0 1IET_00010001
> > root at x86-generic-64:~# multipathd -k'remove map dmpath0'
> > ok
> > root at x86-generic-64:~# multipathd -k'show maps'
> > root at x86-generic-64:~# multipathd -k'add map dmpath0'
> > ok
> > root at x86-generic-64:~# multipathd -k'show maps'
> > root at x86-generic-64:~#
> > Once a map is removed, we are able to add it only using #multipath
> > command and not using multipathd tools.
> >
> > I have fixed the problem with two approaches. I would like you to
> review
> > the same.
> > Patch1 : By making 'remove map dmpath0' to remove only the map and
> not the
> > device. I have added extra functions discard_map and dm_remove_map so
> as
> > to not interfere with the existing code.
> >
> > Patch 2: The approach you have suggested.By getting wwid from the
> mapname
> > and doing coalesce_paths. I have just moved the following code in
> > ev_add_map to cli_add_map.
>
> This is the general idea we'd like to go with. However, looking at the
> latest upstream code, I don't think you should pull code in from
> ev_add_map() to cli_add_map() like your patch does. cli_add_map()
> already calls ev_add_map(), and ev_add_map() is certainly able to add
> the map if it doesn't already exist.
>
> You would just need to call it with
>
> ev_add_map(param, NULL, vecs);
>
> and ev_add_map() will happily create you a new multipath device. All
> you need to do is make sure that all the functions that ev_add_map()
> calls with alias can accept a NULL value there.
>
> This might not be the best way to go about this, however. It turns out
> that right now, even though ev_add_map() technically has the ability to
> create new maps, nothing currently uses it, and it really doesn't make
> sense for it to be there. Instead of just copying that code, you could
> pull the map creation code out of ev_add_map() and add it to
> cli_add_map(), for those situations where the requested device doesn't
> already exist.
>
> But having the code in both cli_add_map() and ev_add_map() when one
> already calls the other doesn't seem necessary.
>
> -Ben
>
>
> >
> > r = get_refwwid(dev, DEV_DEVMAP, vecs->pathvec,&refwwid);
> >
> > if (refwwid) {
> > r = coalesce_paths(vecs, NULL, refwwid,0);
> > dm_lib_release();
> > }
> >
> > changed dev to param.
> >
> > I have tested the same in all 3 versions -0.4.8, 0.4.9 and 0.5.0. It
> would
> > be great if you can review the same so that it doesn't cause any extra
> > side effects.
> > I guess Patch2 is the way u have suggested me in the previous mail.
> Please
> > review it and share your views.
> > Regards,
> > Tejaswini
> > On Fri, Jun 12, 2015 at 2:21 AM, Benjamin Marzinski
> > <[1]bmarzins at redhat.com> wrote:
> >
> > On Wed, Jun 10, 2015 at 11:46:51AM +0530, Tejaswini Poluri wrote:
> > >
> > > > We are testing multipathd tools with all the possible
> options
> > and the
> > > > following fails.
> > > >
> > > > Case 1 : remove and add map.
> > > > root at x86-generic-64:~# multipathd -k'show maps'
> > > > name sysfs uuid
> > > > dmpath0 dm-0 1IET_00010001
> > > > root at x86-generic-64:~# multipathd -k'remove map dmpath0'
> > > > ok
> > > > root at x86-generic-64:~# multipathd -k'show maps'
> > > > root at x86-generic-64:~# multipathd -k'add map dmpath0'
> > > > ok
> > > > root at x86-generic-64:~# multipathd -k'show maps'
> > > > root at x86-generic-64:~#
> > > > Once a map is removed, we are able to add it only using
> > #multipath
> > > > command and not using multipathd tools.
> > >
> > > It is working the way it was designed, but possibly it would
> make
> > sense
> > > to change the design.
> > >
> > > You have mentioned that it would make sense to change the
> design to
> > add
> > > map. Are there plans to change the design ?
> > > I am trying to understand the code flow to change the design.
> Can
> > you
> > > guide me if we should stop removing the device from in the
> remove
> > map code
> > > flow or start adding the device and the map in the add map code
> > flow.
> > >
> > > have tried to understand the remove map code flow of
> multipathd in
> > 0.4.8
> > > code.
> >
> > I think that we want multipath to actually remove the map (instead
> of
> > just not monitoring it) when you call "remove map <map>". We just
> want
> > "add map <map>" to try to create the map if it doesn't exist. To do
> > that, you would need to first firgure out what WWID is associated
> with
> > <map>. Presumably, <map> could either be an alias, wwid, or even the
> > name of a path in the map. Once you found the map, you would have to
> > call the code to create the map.
> >
> > Also, to answer your IRC question, no the 0.4.8 code is not still
> being
> > developed upstream. All upstream patches only go against the
> current
> > head. There are no other upstream branches.
> >
> > -Ben
> > >
> > > ev_remove_map (char * devname, struct vectors * vecs)
> > >
> > > flush_map(mpp, vecs);
> > >
> > > dm_flush_map(mpp->alias,
> DEFAULT_TARGET);
> > >
> > > if (!dm_map_present(mapname))
> > >
> > > return 0;
> > >
> > > if (dm_type(mapname, type) <= 0)
> > >
> > > return 1;
> > >
> > > if (dm_remove_partmaps(mapname))
> > >
> > > return 1;
> > >
> > > if (dm_get_opencount(mapname)) {
> > >
> > > condlog(2, "%s: map in use", mapname);
> > >
> > > return 1;
> > >
> > > }
> > >
> > > r = dm_simplecmd(DM_DEVICE_REMOVE, mapname);
> > >
> > > if (r) {
> > >
> > > condlog(4, "multipath map %s removed", mapname);
> > >
> > > return 0;
> > >
> > > }
> > >
> > >
> > >
> > > orphan_paths(vecs->pathvec, mpp);
> > >
> > > remove_map(mpp, vecs,
> stop_waiter_thread,
> > 1);
> > >
> > > Is removing this below line, the right step to stop removing
> the
> > device ?
> > > r = dm_simplecmd(DM_DEVICE_REMOVE, mapname);
> > >
> > > Regards,
> > >
> > > Tejaswini
> > >
> > > On Mon, Jun 8, 2015 at 11:15 AM, Tejaswini Poluri
> > > <[1][2]tejaswinipoluri3 at gmail.com> wrote:
> > >
> > > Thanks a lot Ben for the quick and detailed reply. I have
> been
> > > struggling to understand and conclude the issues with
> multipath
> > as I am
> > > the only one working from my team. Your inputs help me a lot.
> > Thanks
> > > again.
> > > Regards,
> > > Tejaswini
> > > On Sat, Jun 6, 2015 at 3:36 AM, Benjamin Marzinski
> > > <[2][3]bmarzins at redhat.com> wrote:
> > >
> > > On Fri, Jun 05, 2015 at 02:31:20PM +0530, Tejaswini Poluri
> > wrote:
> > > > Hii Ben,
> > > >
> > > > We are testing multipathd tools with all the possible
> > options and
> > > the
> > > > following fails.
> > > >
> > > > Case 1 : remove and add map.
> > > > root at x86-generic-64:~# multipathd -k'show maps'
> > > > name sysfs uuid
> > > > dmpath0 dm-0 1IET_00010001
> > > > root at x86-generic-64:~# multipathd -k'remove map
> dmpath0'
> > > > ok
> > > > root at x86-generic-64:~# multipathd -k'show maps'
> > > > root at x86-generic-64:~# multipathd -k'add map dmpath0'
> > > > ok
> > > > root at x86-generic-64:~# multipathd -k'show maps'
> > > > root at x86-generic-64:~#
> > > > Once a map is removed, we are able to add it only
> using
> > > #multipath
> > > > command and not using multipathd tools.
> > >
> > > It is working the way it was designed, but possibly it
> would
> > make
> > > sense
> > > to change the design. The "remove map" command, not only
> stops
> > > multipathd from monitoring the multipath device, but it
> removes
> > it
> > > from
> > > the system as well. The "add map" command makes multipath
> > monitor an
> > > already existing multipath device that in wasn't previously
> > > monitoring.
> > > These commands do this for historical reasons. multipathd
> > wasn't
> > > originally in charge of creating multipath devices,
> multipath
> > was.
> > > Once
> > > it had created the device, it ran
> > >
> > > multipathd -k"add map <MAP>"
> > >
> > > to make multipathd start monitoring it. However things
> haven't
> > worked
> > > this way since RHEL4, so possibly "add map" should actually
> > create the
> > > device if it doesn't currently exist.
> > > > Case 2 : Active paths test case
> > > > # while true ; do sleep 3 ; multipathd -k'remove path
> sdb'
> > ;
> > > multipathd
> > > > -k'add path sdb' ; multipathd -k'show maps status' ;
> done
> > > > ok
> > > > ok
> > > > name failback queueing paths dm-st
> > > > dmpath0 - - 1 active // It should be 2.
> > >
> > > This is simply a timing issue. What you are seeing it the
> > number of
> > > active paths. These are paths that the kernel can use. The
> > "add path"
> > > command doesn't update the kernel state. This happens
> later in
> > > response
> > > to the kernel reloading the device table. So, in a second
> or
> > two, this
> > > will say 2, as expected.
> > >
> > > > We would like to know if the test cases are valid and
> if
> > these
> > > are bugs or
> > > > any design issues.
> > > >
> > > > Case 3 : Fail path and reinstate path
> > > > root at x86-generic-64:~# multipathd -k"fail path sdc";
> > multipathd
> > > > -k'reinstate path sdc'; multipathd -k"show paths";
> > > > > [ 3962.708523] device-mapper: multipath: Failing
> path
> > 8:32.
> > > > > ok
> > > > > ok
> > > > > hcil dev dev_t pri dm_st chk_st next_check
> > > > > 4:0:0:1 sdc 8:32 1 [active][faulty] ..........
> > 1/20
> > > <==CHECK
> > > > > 5:0:0:1 sdd 8:48 1 [active][ready] XX........
> > 4/20
> > > > sdc path becomes [active][ready] only after the
> polling
> > interval
> > > but not
> > > > immediately after the reinstate path command.
> > > > You have answered that this is a design issue. But we
> have
> > heard
> > > from our
> > > > test team that the same test case works in RHEL6. Did
> you
> > observe
> > > it?
> > > > I am also finding that the test cases fail because we
> are
> > trying
> > > to do
> > > > multiple commands at one shot. Please share your
> thoughts
> > so
> > > that it
> > > > could help me in debugging the issues further.
> > > >
> > >
> > > It's totally possible that the checker state is immediately
> > updated in
> > > RHEL6. Like I said before, what it currently does,
> although
> > correct,
> > > is confusing, and perhaps we need a different checker
> state for
> > paths
> > > where the "fail path" command has been used.
> > >
> > > -Ben
> > > > Regards,
> > > > Tejaswini
> > > > On Tue, May 19, 2015 at 5:37 PM, Tejaswini Poluri
> > > > <[1][3][4]tejaswinipoluri3 at gmail.com> wrote:
> > > >
> > > > Thanks a lot Ben. I will look into it more.
> > > > On Mon, May 18, 2015 at 9:57 PM, Benjamin Marzinski
> > > > <[2][4][5]bmarzins at redhat.com> wrote:
> > > >
> > > > On Mon, May 18, 2015 at 02:09:27PM +0530,
> Tejaswini
> > Poluri
> > > wrote:
> > > > > Hii,
> > > > > We are trying to test multipath setup in our
> > target and
> > > tried the
> > > > various
> > > > > commands of multipathd demaon and we find the
> > following
> > > error:
> > > > > root at x86-generic-64:~# multipathd -k"fail
> path
> > sdc";
> > > multipathd
> > > > > -k'reinstate path
> > > > > sdc'; multipathd -k"show paths";
> > > > > [ 3962.708523] device-mapper: multipath:
> Failing
> > > path 8:32.
> > > > > ok
> > > > > ok
> > > > > hcil dev dev_t pri dm_st chk_st
> next_check
> > > > > 4:0:0:1 sdc 8:32 1 [active][faulty]
> ..........
> > 1/20
> > > <<<===
> > > > CHECK
> > > > > 5:0:0:1 sdd 8:48 1 [active][ready]
> XX........
> > 4/20
> > > > > sdc path becomes [active][ready] only after
> the
> > polling
> > > interval
> > > > but not
> > > > > immediately after the reinstate path
> command.
> > > > > I am observing this in latest multipath
> tools in
> > ubuntu
> > > machine
> > > > as well.
> > > > > Please let me know if its a known issue or
> if I
> > am doing
> > > > something wrong.
> > > > > Regards.
> > > > > Tejaswini
> > > >
> > > > the reinstate command is supposed to reinstate the
> > device
> > > with the
> > > > kernel, and it does that. The checker state
> doesn't
> > change
> > > until the
> > > > next time that the path is checked. I agree that
> it's
> > odd
> > > that the
> > > > check state switches to faulty as soon as you
> fail the
> > path,
> > > but it
> > > > doesn't switch back until the next check after you
> > reinistate
> > > it.
> > > >
> > > > The issue is that multipathd needs to override the
> > checker
> > > output,
> > > > so that a failed path won't be immeditately
> > reinstated. Once
> > > the
> > > > path comes back, multipathd wants to record the
> switch
> > in the
> > > checker
> > > > thread, so that it can refresh path information
> what
> > wasn't
> > > > automatically done when the path was reinstated.
> > However, it
> > > may make
> > > > more sense to have a different checker state for
> when
> > the
> > > device is
> > > > in the failed state, so that it's obvious that the
> > checker
> > > state is
> > > > being overruled.
> > > >
> > > > -Ben
> > > >
> > > > > --
> > > > > dm-devel mailing list
> > > > > [3][5][6]dm-devel at redhat.com
> > > > >
> > [4][6][7]https://www.redhat.com/mailman/listinfo/dm-devel
> > > >
> > > > --
> > > > dm-devel mailing list
> > > > [5][7][8]dm-devel at redhat.com
> > > >
> > [6][8][9]https://www.redhat.com/mailman/listinfo/dm-devel
> > > >
> > > > References
> > > >
> > > > Visible links
> > > > 1. mailto:[9][10]tejaswinipoluri3 at gmail.com
> > > > 2. mailto:[10][11]bmarzins at redhat.com
> > > > 3. mailto:[11][12]dm-devel at redhat.com
> > > > 4.
> > [12][13]https://www.redhat.com/mailman/listinfo/dm-devel
> > > > 5. mailto:[13][14]dm-devel at redhat.com
> > > > 6.
> > [14][15]https://www.redhat.com/mailman/listinfo/dm-devel
> > >
> > > References
> > >
> > > Visible links
> > > 1. mailto:[16]tejaswinipoluri3 at gmail.com
> > > 2. mailto:[17]bmarzins at redhat.com
> > > 3. mailto:[18]tejaswinipoluri3 at gmail.com
> > > 4. mailto:[19]bmarzins at redhat.com
> > > 5. mailto:[20]dm-devel at redhat.com
> > > 6. [21]https://www.redhat.com/mailman/listinfo/dm-devel
> > > 7. mailto:[22]dm-devel at redhat.com
> > > 8. [23]https://www.redhat.com/mailman/listinfo/dm-devel
> > > 9. mailto:[24]tejaswinipoluri3 at gmail.com
> > > 10. mailto:[25]bmarzins at redhat.com
> > > 11. mailto:[26]dm-devel at redhat.com
> > > 12. [27]https://www.redhat.com/mailman/listinfo/dm-devel
> > > 13. mailto:[28]dm-devel at redhat.com
> > > 14. [29]https://www.redhat.com/mailman/listinfo/dm-devel
> >
> > References
> >
> > Visible links
> > 1. mailto:bmarzins at redhat.com
> > 2. mailto:tejaswinipoluri3 at gmail.com
> > 3. mailto:bmarzins at redhat.com
> > 4. mailto:tejaswinipoluri3 at gmail.com
> > 5. mailto:bmarzins at redhat.com
> > 6. mailto:dm-devel at redhat.com
> > 7. https://www.redhat.com/mailman/listinfo/dm-devel
> > 8. mailto:dm-devel at redhat.com
> > 9. https://www.redhat.com/mailman/listinfo/dm-devel
> > 10. mailto:tejaswinipoluri3 at gmail.com
> > 11. mailto:bmarzins at redhat.com
> > 12. mailto:dm-devel at redhat.com
> > 13. https://www.redhat.com/mailman/listinfo/dm-devel
> > 14. mailto:dm-devel at redhat.com
> > 15. https://www.redhat.com/mailman/listinfo/dm-devel
> > 16. mailto:tejaswinipoluri3 at gmail.com
> > 17. mailto:bmarzins at redhat.com
> > 18. mailto:tejaswinipoluri3 at gmail.com
> > 19. mailto:bmarzins at redhat.com
> > 20. mailto:dm-devel at redhat.com
> > 21. https://www.redhat.com/mailman/listinfo/dm-devel
> > 22. mailto:dm-devel at redhat.com
> > 23. https://www.redhat.com/mailman/listinfo/dm-devel
> > 24. mailto:tejaswinipoluri3 at gmail.com
> > 25. mailto:bmarzins at redhat.com
> > 26. mailto:dm-devel at redhat.com
> > 27. https://www.redhat.com/mailman/listinfo/dm-devel
> > 28. mailto:dm-devel at redhat.com
> > 29. https://www.redhat.com/mailman/listinfo/dm-devel
>
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listman.redhat.com/archives/dm-devel/attachments/20150626/0b3875eb/attachment.htm>
More information about the dm-devel
mailing list