[3.19.y-ckt stable] Patch "btrfs: initialize the seq counter in struct btrfs_device" has been added to the 3.19.y-ckt tree

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    btrfs: initialize the seq counter in struct btrfs_device

to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.8-ckt14.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From d37eba3d5d468f186e9f4406005092ac052d65a8 Mon Sep 17 00:00:00 2001
From: Sebastian Andrzej Siewior <bigeasy at linutronix.de>
Date: Fri, 15 Jan 2016 14:37:15 +0100
Subject: btrfs: initialize the seq counter in struct btrfs_device

commit 546bed631203344611f42b2af1d224d2eedb4e6b upstream.

I managed to trigger this:
| INFO: trying to register non-static key.
| the code is fine but needs lockdep annotation.
| turning off the locking correctness validator.
| CPU: 1 PID: 781 Comm: systemd-gpt-aut Not tainted 4.4.0-rt2+ #14
| Hardware name: ARM-Versatile Express
| [<80307cec>] (dump_stack)
| [<80070e98>] (__lock_acquire)
| [<8007184c>] (lock_acquire)
| [<80287800>] (btrfs_ioctl)
| [<8012a8d4>] (do_vfs_ioctl)
| [<8012ac14>] (SyS_ioctl)

so I think that btrfs_device_data_ordered_init() is not invoked behind
a macro somewhere.

Fixes: 7cc8e58d53cd ("Btrfs: fix unprotected device's variants on 32bits machine")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy at linutronix.de>
Reviewed-by: David Sterba <dsterba at suse.com>
Signed-off-by: David Sterba <dsterba at suse.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 fs/btrfs/volumes.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 50c5a87..ee927c6 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -152,6 +152,7 @@ static struct btrfs_device *__alloc_device(void)
 	spin_lock_init(&dev->reada_lock);
 	atomic_set(&dev->reada_in_flight, 0);
 	atomic_set(&dev->dev_stats_ccnt, 0);
+	btrfs_device_data_ordered_init(dev);
 	INIT_RADIX_TREE(&dev->reada_zones, GFP_NOFS & ~__GFP_WAIT);
 	INIT_RADIX_TREE(&dev->reada_extents, GFP_NOFS & ~__GFP_WAIT);

--
1.9.1