| Date | Wed, 09 Nov 2011 13:32:34 -0800 | From | Greg KH <> | Subject | [107/264] md/raid5: fix bug that could result in reads from a failed device. |
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3.1-stable review patch. If anyone has any objections, please let me know.
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From: NeilBrown <neilb@suse.de>
commit 355840e7a7e56bb2834fd3b0da64da5465f8aeaa upstream.
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 @@ -3069,7 +3069,7 @@ static void analyse_stripe(struct stripe } } else if (test_bit(In_sync, &rdev->flags)) set_bit(R5_Insync, &dev->flags); - else { + else if (!test_bit(Faulty, &rdev->flags)) { /* in sync if before recovery_offset */ if (sh->sector + STRIPE_SECTORS <= rdev->recovery_offset) set_bit(R5_Insync, &dev->flags);
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