RE: [PATCH] FIX: Cannot continue reshape if incremental assembly is used

From: "Dorau, Lukasz" <lukasz.dorau@intel.com>
To: NeilBrown <neilb@suse.de>
Cc: "linux-raid@vger.kernel.org" <linux-raid@vger.kernel.org>,
	"Labun, Marcin" <Marcin.Labun@intel.com>,
	"Ciechanowski, Ed" <ed.ciechanowski@intel.com>,
	"Williams, Dan J" <dan.j.williams@intel.com>
Subject: RE: [PATCH] FIX: Cannot continue reshape if incremental assembly is used
Date: Thu, 8 Sep 2011 08:26:53 +0000	[thread overview]
Message-ID: <D9FFE20C522965449E182ACE73889AEB02034E@IRSMSX101.ger.corp.intel.com> (raw)
In-Reply-To: <20110907123759.3b4106bb@notabene.brown>

On Wed, Sep 07, 2011 4:38 AM Neil Brown <neilb@suse.de> wrote:
> 
> On Tue, 6 Sep 2011 14:34:42 -0700 Dan Williams <dan.j.williams@intel.com>
> wrote:
> 
> > On Thu, Sep 1, 2011 at 6:18 AM, Lukasz Dorau <lukasz.dorau@intel.com>
> wrote:
> > > Description of the bug:
> > > Interrupted reshape cannot be continued using incremental assembly.
> > > Array becomes inactive.
> > >
> > > Cause of the bug:
> > > Reshape tried to continue with insufficient number of disks
> > > added by incremental assembly (tested using capacity expansion).
> > >
> > > Solution:
> > > During reshape adding disks to array should be blocked until
> > > minimum required number of disks is ready to be added.
> >
> > Can you provide a script test-case to reproduce the problem?
> 

The patch originally was intended to fix the following issue:

export MDADM_EXPERIMENTAL=1
mdadm -C /dev/md/imsm0 -amd -e imsm -n 2 /dev/sda /dev/sdb -R
mdadm -C /dev/md/raid1-0 -amd -l1  --size 5G -n 2 /dev/sda /dev/sdb -R 
mdadm --wait /dev/md/raid1-0 
mdadm /dev/md/imsm0 --add /dev/sdc
mdadm /dev/md/imsm0 --add /dev/sdd
mdadm -G /dev/md/raid1-0 -l0 
mdadm -G /dev/md/imsm0 -n 4 
sleep 5
mdadm -Ss
mdadm -I /dev/sda
mdadm -I /dev/sdb
# At this moment mdadm tries to start array and continue reshape,
# however there is insufficient number of disks, so it fails
# (not enough operational devices - failed to run raid set)
# - see syslog below.
mdadm -I /dev/sdc
# array is not started and reshape does not continue
mdadm -I /dev/sdd
# array is not started and reshape does not continue

### syslog:
kernel: md: bind<sda>
kernel: md: bind<sdb>
kernel: md: bind<sda>
kernel: md: bind<sdb>
kernel: bio: create slab <bio-1> at 1
kernel: md/raid:md126: reshape will continue
kernel: md/raid:md126: device sdb operational as raid disk 0
kernel: md/raid:md126: device sda operational as raid disk 1
kernel: md/raid:md126: allocated 5334kB
kernel: md/raid:md126: not enough operational devices (3/5 failed)
kernel: md/raid:md126: failed to run raid set.
kernel: md: pers->run() failed ...
kernel: md: bind<sdc>
kernel: md: bind<sdd>
kernel: md: bind<sdd>
kernel: md: bind<sdc>
kernel: md: export_rdev(sda)
kernel: md: export_rdev(sdb)

Regards,
Lukasz 

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