This is a note to let you know that I've just added the patch titled

    md/raid5: fix calculate of 'degraded' when a replacement becomes active.

to the 3.4-stable tree which can be found at:
    
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     md-raid5-fix-calculate-of-degraded-when-a-replacement-becomes-active.patch
and it can be found in the queue-3.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.


>From e5c86471f933608db5d43679f84cb4346c32033e Mon Sep 17 00:00:00 2001
From: NeilBrown <[email protected]>
Date: Wed, 19 Sep 2012 12:52:30 +1000
Subject: md/raid5: fix calculate of 'degraded' when a replacement becomes 
active.

From: NeilBrown <[email protected]>

commit e5c86471f933608db5d43679f84cb4346c32033e upstream.

When a replacement device becomes active, we mark the device that it
replaces as 'faulty' so that it can subsequently get removed.
However 'calc_degraded' only pays attention to the primary device, not
the replacement, so the array appears to become degraded, which is
wrong.

So teach 'calc_degraded' to consider any replacement if a primary
device is faulty.

This is suitable for -stable as an incorrect 'degraded' value can
confuse md and could lead to data corruption.
This is only relevant for 3.3 and later.

Reported-by: Robin Hill <[email protected]>
Reported-by: John Drescher <[email protected]>
Signed-off-by: NeilBrown <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 drivers/md/raid5.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -380,6 +380,8 @@ static int calc_degraded(struct r5conf *
        degraded = 0;
        for (i = 0; i < conf->previous_raid_disks; i++) {
                struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
+               if (rdev && test_bit(Faulty, &rdev->flags))
+                       rdev = rcu_dereference(conf->disks[i].replacement);
                if (!rdev || test_bit(Faulty, &rdev->flags))
                        degraded++;
                else if (test_bit(In_sync, &rdev->flags))
@@ -404,6 +406,8 @@ static int calc_degraded(struct r5conf *
        degraded2 = 0;
        for (i = 0; i < conf->raid_disks; i++) {
                struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
+               if (rdev && test_bit(Faulty, &rdev->flags))
+                       rdev = rcu_dereference(conf->disks[i].replacement);
                if (!rdev || test_bit(Faulty, &rdev->flags))
                        degraded2++;
                else if (test_bit(In_sync, &rdev->flags))


Patches currently in stable-queue which might be from [email protected] are

queue-3.4/md-raid5-fix-calculate-of-degraded-when-a-replacement-becomes-active.patch
queue-3.4/md-make-sure-metadata-is-updated-when-spares-are-activated-or-removed.patch
queue-3.4/md-don-t-truncate-size-at-4tb-for-raid0-and-linear.patch
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