| From neilb@suse.de Wed Dec 14 16:01:18 2011 |
| From: NeilBrown <neilb@suse.de> |
| Date: Thu, 15 Dec 2011 10:54:39 +1100 |
| Subject: md/raid5: fix bug that could result in reads from a failed device. |
| To: stable@vger.kernel.org |
| Cc: linux RAID <linux-raid@vger.kernel.org>, Alexander Lyakas <alex.bolshoy@gmail.com>, tim.gardner@canonical.com |
| Message-ID: <20111215105439.628fe074@notabene.brown> |
| |
| |
| From: NeilBrown <neilb@suse.de> |
| |
| commit 355840e7a7e56bb2834fd3b0da64da5465f8aeaa upstream. |
| |
| commit a847627709b3402163d99f7c6fda4a77bcd6b51b in linux-3.0.9 |
| attempted to backport this to 3.0 but only made one change were two |
| were necessary. This add the second change. |
| |
| This bug was introduced in 415e72d034c50520ddb7ff79e7d1792c1306f0c9 |
| which was in 2.6.36. |
| |
| There is a small window of time between when a device fails and when |
| it is removed from the array. During this time we might still read |
| from it, but we won't write to it - so it is possible that we could |
| read stale data. |
| |
| We didn't need the test of 'Faulty' before because the test on |
| In_sync is sufficient. Since we started allowing reads from the early |
| part of non-In_sync devices we need a test on Faulty too. |
| |
| This is suitable for any kernel from 2.6.36 onwards, though the patch |
| might need a bit of tweaking in 3.0 and earlier. |
| |
| Signed-off-by: NeilBrown <neilb@suse.de> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
| --- |
| drivers/md/raid5.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- a/drivers/md/raid5.c |
| +++ b/drivers/md/raid5.c |
| @@ -3078,7 +3078,7 @@ static void handle_stripe5(struct stripe |
| /* Not in-sync */; |
| else if (test_bit(In_sync, &rdev->flags)) |
| set_bit(R5_Insync, &dev->flags); |
| - else { |
| + else if (!test_bit(Faulty, &rdev->flags)) { |
| /* could be in-sync depending on recovery/reshape status */ |
| if (sh->sector + STRIPE_SECTORS <= rdev->recovery_offset) |
| set_bit(R5_Insync, &dev->flags); |
