Messages in this thread | | | Date | Tue, 2 Sep 2003 19:04:28 -0700 | From | Mike Fedyk <> | Subject | Re: 2.6 md raid5 disk faulty marking bug was: md: bug in file raid5.c, line 1909 in 2.4.22-pre7 |
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On Tue, Aug 26, 2003 at 09:20:05AM +1000, Neil Brown wrote: > On Friday August 22, mfedyk@matchmail.com wrote: > > > As far as I can see, the 2.4 code would never set just MD_DISK_REMOVED > > > (though it really should cope with it). It is possible that the 2.6 > > > code does. Has this array had 2.6 running on it? Does it have any > > > interesting history? > > > > Yes, it was running 2.6-test2-mm2 or so (don't remember exactly, I can check > > though if needed) previously, but I didn't notice any bug messages from > > there, and seeing that it was 2.4 I was surprised to see bug > > messages from md. > > The 2.4 code is very fragile. It can easily bug if the superblock > looks wrong in some obscure way. > > > > > Do you have any patches for 2.6 md? Right now this system is still in > > testing, and I'd like to help get this code path tested, and fixed. > > The following should fix it. > With this applied to 2.6, you can simply > start the array under 2.6 > stop the array > reboot into 2.4 > and it should be fine again. > > NeilBrown > > ================================================== > Fix md superblock incompatabilities with 2.4 kernels. > > 2.4 kernels are very fussy about some values in the superblock, and > 2.6 got them wrong. This fixes it. >
Yes, I can confirm this fixes it for me. I applied it to 2.6.0-test4-mm3-1, without any troubles.
I tried rebuilding the array with 2.4 (zeroing the superblock in mdadm and everything), but that didn't fix it, so I rebuilt with 2.6 and the below patch, and do far so good. I'll be beating on this machine some more...
Mike
> > ----------- Diffstat output ------------ > ./drivers/md/md.c | 13 ++++++------- > 1 files changed, 6 insertions(+), 7 deletions(-) > > diff ./drivers/md/md.c~current~ ./drivers/md/md.c > --- ./drivers/md/md.c~current~ 2003-08-24 08:07:18.000000000 +1000 > +++ ./drivers/md/md.c 2003-08-26 09:11:39.000000000 +1000 > @@ -638,14 +638,13 @@ static void super_90_sync(mddev_t *mddev > /* make rdev->sb match mddev data.. > * > * 1/ zero out disks > - * 2/ Add info for each disk, keeping track of highest desc_nr > - * 3/ any empty disks < highest become removed > + * 2/ Add info for each disk, keeping track of highest desc_nr (next_spare); > + * 3/ any empty disks < next_spare become removed > * > * disks[0] gets initialised to REMOVED because > * we cannot be sure from other fields if it has > * been initialised or not. > */ > - int highest = 0; > int i; > int active=0, working=0,failed=0,spare=0,nr_disks=0; > > @@ -716,17 +715,17 @@ static void super_90_sync(mddev_t *mddev > spare++; > working++; > } > - if (rdev2->desc_nr > highest) > - highest = rdev2->desc_nr; > } > > - /* now set the "removed" bit on any non-trailing holes */ > - for (i=0; i<highest; i++) { > + /* now set the "removed" and "faulty" bits on any missing devices */ > + for (i=0 ; i < mddev->raid_disks ; i++) { > mdp_disk_t *d = &sb->disks[i]; > if (d->state == 0 && d->number == 0) { > d->number = i; > d->raid_disk = i; > d->state = (1<<MD_DISK_REMOVED); > + d->state |= (1<<MD_DISK_FAULTY); > + failed++; > } > } > sb->nr_disks = nr_disks; > - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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