[PATCH v2 1/2] btrfs: add function to device list delete

[Anand Jain <anand.jain@oracle.com>]

We need device delete from the dev_list so create a new function,
instead of refactor of btrfs_free_stale_device() because,
btrfs_free_stale_device() doesn't hold device_list_mutex which
is actually needed here.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
---
v1: title of this patch
  btrfs: refactor btrfs_free_stale_device() to get device list delete
v2:
 add new function instead of peal from
 btrfs_free_stale_device() to delete a device from the device list,
 since btrfs_free_stale_device() does not hold device_list_mutex,
 may be it can be fixed later.


 /btrfs/volumes.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index bddf75d5e6a0..68f1dd44385b 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -546,6 +546,27 @@ static void pending_bios_fn(struct btrfs_work *work)
 	run_scheduled_bios(device);
 }
 
+static void delete_device_from_list(struct btrfs_device *device)
+{
+	struct btrfs_fs_devices *fs_devices;
+	fs_devices = device->fs_devices;
+
+	lockdep_assert_held(&uuid_mutex);
+
+	mutex_lock(&fs_devices->device_list_mutex);
+	fs_devices->num_devices--;
+	list_del(&device->dev_list);
+	mutex_unlock(&fs_devices->device_list_mutex);
+
+	rcu_string_free(device->name);
+	kfree(device);
+
+	if (fs_devices->num_devices == 0) {
+		btrfs_sysfs_remove_fsid(fs_devices);
+		list_del(&fs_devices->list);
+		free_fs_devices(fs_devices);
+	}
+}
 
 void btrfs_free_stale_device(struct btrfs_device *cur_dev)
 {
-- 
2.15.0