From: NeilBrown <[email protected]> This code was written long ago when it was not possible to reshape a degraded array. Now it is so the current level of degraded-ness needs to be taken in to account. Also newly addded devices should only reduce degradedness if they are deemed to be in-sync.
In particular, if you convert a RAID5 to a RAID6, and increase the number of devices at the same time, then the 5->6 conversion will make the array degraded so the current code will produce a wrong value for 'degraded' - "-1" to be precise. If the reshape runs to completion end_reshape will calculate a correct new value for 'degraded', but if a device fails during the reshape an incorrect decision might be made based on the incorrect value of "degraded". This patch is suitable for 2.6.32-stable and if they are still open, 2.6.31-stable and 2.6.30-stable as well. Cc: [email protected] Reported-by: Michael Evans <[email protected]> Signed-off-by: NeilBrown <[email protected]> drivers/md/raid5.c | 11 +++++++---- 1 files changed, 7 insertions(+), 4 deletions(-) --- http://git.linuxtv.org/v4l-dvb.git?a=commitdiff;h=9eb07c259207d048e3ee8be2a77b2a4680b1edd4 diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index e84204e..b5629c3 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -5464,11 +5464,11 @@ static int raid5_start_reshape(mddev_t *mddev) !test_bit(Faulty, &rdev->flags)) { if (raid5_add_disk(mddev, rdev) == 0) { char nm[20]; - if (rdev->raid_disk >= conf->previous_raid_disks) + if (rdev->raid_disk >= conf->previous_raid_disks) { set_bit(In_sync, &rdev->flags); - else + added_devices++; + } else rdev->recovery_offset = 0; - added_devices++; sprintf(nm, "rd%d", rdev->raid_disk); if (sysfs_create_link(&mddev->kobj, &rdev->kobj, nm)) @@ -5480,9 +5480,12 @@ static int raid5_start_reshape(mddev_t *mddev) break; } + /* When a reshape changes the number of devices, ->degraded + * is measured against the large of the pre and post number of + * devices.*/ if (mddev->delta_disks > 0) { spin_lock_irqsave(&conf->device_lock, flags); - mddev->degraded = (conf->raid_disks - conf->previous_raid_disks) + mddev->degraded += (conf->raid_disks - conf->previous_raid_disks) - added_devices; spin_unlock_irqrestore(&conf->device_lock, flags); } _______________________________________________ linuxtv-commits mailing list [email protected] http://www.linuxtv.org/cgi-bin/mailman/listinfo/linuxtv-commits
