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| author | NeilBrown <neilb@suse.de> | 2010-02-09 12:31:47 +1100 |
|---|---|---|
| committer | NeilBrown <neilb@suse.de> | 2010-02-09 16:34:29 +1100 |
| commit | 9eb07c259207d048e3ee8be2a77b2a4680b1edd4 (patch) | |
| tree | aad711b891fd43920c832da2158aab0764c7fe49 /drivers/md | |
| parent | 6339204ecc2aa2067a99595522de0403f0854bb8 (diff) | |
| download | linux-9eb07c259207d048e3ee8be2a77b2a4680b1edd4.tar.gz linux-9eb07c259207d048e3ee8be2a77b2a4680b1edd4.tar.bz2 linux-9eb07c259207d048e3ee8be2a77b2a4680b1edd4.zip | |
md: fix 'degraded' calculation when starting a reshape.
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: stable@kernel.org
Reported-by: Michael Evans <mjevans1983@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/raid5.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index e84204eb12df..b5629c3e14fa 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); } |