From: Anand Jain <anand.jain@oracle.com>
Date: Thu, 23 Jun 2016 12:54:07 +0000 (+0800)
Subject: btrfs: make sure device is synced before return
X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=e2bf6e89b4c71ea08223f13a700cfd0b576f7e7a;p=deliverable%2Flinux.git

btrfs: make sure device is synced before return

An inconsistent behavior due to stale reads from the
disk was reported

  mail-archive.com/linux-btrfs@vger.kernel.org/msg54188.html

This patch will make sure devices are synced before
return in the unmount thread.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index e54b3fe92e90..51bd3ee8e64f 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -870,6 +870,11 @@ static void btrfs_close_one_device(struct btrfs_device *device)
 	if (device->missing)
 		fs_devices->missing_devices--;
 
+	if (device->bdev && device->writeable) {
+		sync_blockdev(device->bdev);
+		invalidate_bdev(device->bdev);
+	}
+
 	new_device = btrfs_alloc_device(NULL, &device->devid,
 					device->uuid);
 	BUG_ON(IS_ERR(new_device)); /* -ENOMEM */