From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Brown Subject: Re: [md PATCH 4/5] md: Fix: BIO I/O Error during reshape for external metadata Date: Wed, 16 Jun 2010 15:02:37 +1000 Message-ID: <20100616150237.0009d6d1@notabene.brown> References: <905EDD02F158D948B186911EB64DB3D11EECE8A6@irsmsx503.ger.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <905EDD02F158D948B186911EB64DB3D11EECE8A6@irsmsx503.ger.corp.intel.com> Sender: linux-raid-owner@vger.kernel.org To: "Kwolek, Adam" Cc: "linux-raid@vger.kernel.org" , "Williams, Dan J" , "Ciechanowski, Ed" List-Id: linux-raid.ids On Wed, 9 Jun 2010 15:22:27 +0100 "Kwolek, Adam" wrote: > (md: Online Capacity Expansion for IMSM) > When sum of added disks and degraded disks is greater than max_degraded number, reshape decides that stripe is broken, so bio i/o error is a result. > Added disks without data has no impact on volume degradation (contains no data so far), so we have to be sure that all disks used to reshape has In_sync flag set. > We have to do this for disks without data. Again, I'm not really following you. I agree that devices that are added to make up numbers for a shape should be marked In_sync, but that is already happening, roughly in the middle of raid5_start_reshape. Again, can you give me a specific situation where the current code does the wrong thing? Thanks, NeilBrown > --- > > drivers/md/raid5.c | 17 ++++++++++++++++- > 1 files changed, 16 insertions(+), 1 deletions(-) > > diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index dc25a32..cb74045 100644 > --- a/drivers/md/raid5.c > +++ b/drivers/md/raid5.c > @@ -5468,7 +5468,7 @@ static int raid5_start_reshape(mddev_t *mddev) > /* Add some new drives, as many as will fit. > * We know there are enough to make the newly sized array work. > */ > - list_for_each_entry(rdev, &mddev->disks, same_set) > + list_for_each_entry(rdev, &mddev->disks, same_set) { > if (rdev->raid_disk < 0 && > !test_bit(Faulty, &rdev->flags)) { > if (raid5_add_disk(mddev, rdev) == 0) { @@ -5488,6 +5488,21 @@ static int raid5_start_reshape(mddev_t *mddev) > } else > break; > } > + /* if there is Online Capacity Expansion > + * on degraded array for external meta > + */ > + if (mddev->external && > + (conf->raid_disks <= (disk_count + conf->max_degraded))) { > + /* check if not spare */ > + if (!(rdev->raid_disk < 0 && > + !test_bit(Faulty, &rdev->flags))) > + /* make sure that all disks, > + * even added previously have > + * in sync flag set > + */ > + set_bit(In_sync, &rdev->flags); > + } > + } > > /* When a reshape changes the number of devices, ->degraded > * is measured against the large of the pre and post number of >