diff options
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/raid5.c | 22 |
1 files changed, 16 insertions, 6 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 9aab66fd1003..657634a7e8d1 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -3557,6 +3557,7 @@ static int need_this_block(struct stripe_head *sh, struct stripe_head_state *s, struct r5dev *fdev[2] = { &sh->dev[s->failed_num[0]], &sh->dev[s->failed_num[1]] }; int i; + bool force_rcw = (sh->raid_conf->rmw_level == PARITY_DISABLE_RMW); if (test_bit(R5_LOCKED, &dev->flags) || @@ -3615,18 +3616,27 @@ static int need_this_block(struct stripe_head *sh, struct stripe_head_state *s, * devices must be read. */ return 1; + + if (s->failed >= 2 && + (fdev[i]->towrite || + s->failed_num[i] == sh->pd_idx || + s->failed_num[i] == sh->qd_idx) && + !test_bit(R5_UPTODATE, &fdev[i]->flags)) + /* In max degraded raid6, If the failed disk is P, Q, + * or we want to read the failed disk, we need to do + * reconstruct-write. + */ + force_rcw = true; } - /* If we are forced to do a reconstruct-write, either because - * the current RAID6 implementation only supports that, or - * because parity cannot be trusted and we are currently - * recovering it, there is extra need to be careful. + /* If we are forced to do a reconstruct-write, because parity + * cannot be trusted and we are currently recovering it, there + * is extra need to be careful. * If one of the devices that we would need to read, because * it is not being overwritten (and maybe not written at all) * is missing/faulty, then we need to read everything we can. */ - if (sh->raid_conf->level != 6 && - sh->raid_conf->rmw_level != PARITY_DISABLE_RMW && + if (!force_rcw && sh->sector < sh->raid_conf->mddev->recovery_cp) /* reconstruct-write isn't being forced */ return 0; |