[lkml]   [2011]   [Nov]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[086/262] md/raid5: fix bug that could result in reads from a failed device.
3.0-stable review patch.  If anyone has any objections, please let me know.


From: NeilBrown <>

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 <>
Signed-off-by: Greg Kroah-Hartman <>

drivers/md/raid5.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -3369,7 +3369,7 @@ static void handle_stripe6(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)) {
/* in sync if before recovery_offset */
if (sh->sector + STRIPE_SECTORS <= rdev->recovery_offset)
set_bit(R5_Insync, &dev->flags);

 \ /
  Last update: 2011-11-10 06:19    [W:0.984 / U:1.576 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site