[PATCH 3.4 044/107] md/raid1: fix test for 'was read error from last working device'.

lizf
2016-03-16T08:09:47Z

From: NeilBrown <neilb@suse.com>

3.4.111-rc1 review patch. If anyone has any objections, please let me know.

------------------

commit 34cab6f42003cb06f48f86a86652984dec338ae9 upstream.

When we get a read error from the last working device, we don't
try to repair it, and don't fail the device. We simple report a
read error to the caller.

However the current test for 'is this the last working device' is
wrong.
When there is only one fully working device, it assumes that a
non-faulty device is that device. However a spare which is rebuilding
would be non-faulty but so not the only working device.

So change the test from "!Faulty" to "In_sync". If ->degraded says
there is only one fully working device and this device is in_sync,
this must be the one.

This bug has existed since we allowed read_balance to read from
a recovering spare in v3.0

Reported-and-tested-by: Alexander Lyakas <alex.bolshoy@gmail.com>
Fixes: 76073054c95b ("md/raid1: clean up read_balance.")
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Zefan Li <lizefan@huawei.com>
---
drivers/md/raid1.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 75e66c6..27af2f3 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -314,7 +314,7 @@ static void raid1_end_read_request(struct bio *bio, int error)
spin_lock_irqsave(&conf->device_lock, flags);
if (r1_bio->mddev->degraded == conf->raid_disks ||
(r1_bio->mddev->degraded == conf->raid_disks-1 &&
- !test_bit(Faulty, &conf->mirrors[mirror].rdev->flags)))
+ test_bit(In_sync, &conf->mirrors[mirror].rdev->flags)))
uptodate = 1;
spin_unlock_irqrestore(&conf->device_lock, flags);
}
--
1.9.1