On Tue, 27 Nov 2012 18:10:20 -0800 Ross Boylan <ross@xxxxxxxxxxxxxxxx> wrote:
> On Wed, 2012-11-28 at 08:30 +1100, NeilBrown wrote:
> > On Tue, 27 Nov 2012 10:28:33 -0800 Ross Boylan <ross@xxxxxxxxxxxxxxxx> wrote:
> >
> > > On Wed, 2012-11-21 at 08:43 +1100, NeilBrown wrote:
> > > > On Tue, 20 Nov 2012 09:55:41 -0800 Ross Boylan <ross@xxxxxxxxxxxxxxxx> wrote:
> > > >
> > > > > While switching the disks a RAID 1 is based on I used the --wait command
> > > > > to wait for the rebuild to finish. It returned immediately, but a
> > > > > subsequent query showed it had not been rebuilt. Have I misunderstood
> > > > > something, or is this an error?
> > > > >
> > > > > While doing these commands a much larger rebuild was going on with a
> > > > > different array, involving some of the same physical disks but different
> > > > > partitions. The partitions being rebuilt are on different physical
> > > > > disks for the different arrays.
> > > > >
> > > > > Here are the logs, with version info at the end (Debian Lenny + more
> > > > > recent kernel):
> > > > ....
> > > >
> > > > > markov:~# uname -a
> > > > > Linux markov 2.6.32-5-amd64 #1 SMP Wed Jan 12 03:40:32 UTC 2011 x86_64 GNU/Linux
> > > > > markov:~# mdadm --version
> > > > > mdadm - v2.6.7.2 - 14th November 2008
> > > > >
> > > > >
> > > > > I notice that in this case, unlike the other array, the message during
> > > > > the rebuild (the last detail report) does not include a line like
> > > > > Rebuild Status : 0% complete
> > > > >
> > > > > I just tried --wait again to see if there was some kind of race, but
> > > > > once again it returned immediately, though detail says the spare is
> > > > > rebuilding.
> > > >
> > > > Can you test this patch to see if it fixes the problem?
> > > >
> > > > diff --git a/Monitor.c b/Monitor.c
> > > > index c4d57c3..a5e7aaa 100644
> > > > --- a/Monitor.c
> > > > +++ b/Monitor.c
> > > > @@ -973,7 +973,7 @@ int Wait(char *dev)
> > > > if (e->devnum == devnum)
> > > > break;
> > > >
> > > > - if (!e || e->percent < 0) {
> > > > + if (!e || e->percent == RESYNC_NONE) {
> > > > if (e && e->metadata_version &&
> > > > strncmp(e->metadata_version, "external:", 9) == 0) {
> > > > if (is_subarray(&e->metadata_version[9]))
> > > >
> > > >
> > > > NeilBrown
> > > My source for 2.6.7.2 looks somewhat different. It only has 627 lines;
> > > I think this is the relevant code (at the end of the file):
> > > /* Not really Monitor but ... */
> > > int Wait(char *dev)
> > > {
> > > struct stat stb;
> > > int devnum;
> > > int rv = 1;
> > >
> > > if (stat(dev, &stb) != 0) {
> > > fprintf(stderr, Name ": Cannot find %s: %s\n", dev,
> > > strerror(errno));
> > > return 2;
> > > }
> > > if (major(stb.st_rdev) == MD_MAJOR)
> > > devnum = minor(stb.st_rdev);
> > > else
> > > devnum = -1-(minor(stb.st_rdev)/64);
> > >
> > > while(1) {
> > > struct mdstat_ent *ms = mdstat_read(1, 0);
> > > struct mdstat_ent *e;
> > >
> > > for (e=ms ; e; e=e->next)
> > > if (e->devnum == devnum)
> > > break;
> > >
> > > if (!e || e->percent < 0) {
> > > free_mdstat(ms);
> > > return rv;
> > > }
> > > free(ms);
> > > rv = 0;
> > > mdstat_wait(5);
> > > }
> > > }
> > >
> > >
> > > The section
> > > if (!e || e->percent < 0) {
> > > free_mdstat(ms);
> > > return rv;
> > > is the only one with e->percent < 0. Is it OK to change that to
> > > if (!e || e->percent == RESYNC_NONE) {?
> > >
> > >
> >
> > That's the right place to make the change, bit it won't compile.
> > RESYNC_NONE isn't defined in that version of mdadm, and you would need to
> > make some changes in mdstat.c where ent->percent is set.
> > Current code has
> >
> >
> > if (l > 8 && strcmp(w+l-8, "=DELAYED") == 0)
> > ent->percent = RESYNC_DELAYED;
> > if (l > 8 && strcmp(w+l-8, "=PENDING") == 0)
> > ent->percent = RESYNC_PENDING;
> >
> > which is completely missing from 2.6.7.2. You'd be a lot better off starting
> > with 3.2.6 and adding the patch to that.
> >
> > NeilBrown
> I think I'm going to have to pass on testing for now, as the
> alternatives appear too high risk:
> 1) I got the debianized source for 3.2.5 (for some reason 3.2.6 is not
> there yet). It depends on a variety of package versions that post-date
> my lenny system. So it will not install unless I override those, or
> located/backport more recent versions of the other packages. Since this
> is messing with core areas of the system (grub, udev, initscripts) it
> seems unwise to attempt backports.
>
> 2) I considered patching 2.6.7.2 in place with the additional info you
> provided, but I'm not sure if you're sayiing the mdstat.c changes alone
> are sufficient, or if I need to change Monitor.c in some way.
Looks like I communicated quite effectively :-) I'm not sure. I thought
about making a patch fro 2.6.7.2 and quickly decided that just upgrading
would be easiest.
You don't need to use the debian version. Just
git clone git://neil.brown.name/mdadm
cd mdadm
git checkout 3.2.5
make
make install
Of course you would void your support contract with Debian....
>
> 3) I could just dump your 3.2.6 upstream source over my current 2.6.7.2
> Debianized directory. But then I'd need to figure out what Debian
> patches I need to reapply, and wonder if it would all work in a Lenny
> environment.
I don't think you need any Debian patches.
>
> I'd like to help, but since this is just a reporting problem for me I
> don't want to risk screwing things up further. I might be able to do 2)
> with a little more information.
>
> BTW, I reviewed the udev rules for mdadm on my system and in the 2.6.7.2
> package, and it does not appear that incremental assembly is being
> attempted. That's not relevant to this thread, but does matter for
> some of my other ones. Also, the 3.2.5 Debian package's udev rules say
> ## DISABLED: Incremental udev assembly disabled
> ## ** this is a Debian-specific change **
> GOTO="md_inc_skip"
>
>
Ahhh.. "make install" will change the udev script. So maybe "make install"
wouldn't quite be such a good idea.
NeilBrown
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