Btrfs: cleanup the similar code of the fs root read

There are several functions whose code is similar, such as
  btrfs_find_last_root()
  btrfs_read_fs_root_no_radix()

Besides that, some functions are invoked twice, it is unnecessary,
for example, we are sure that all roots which is found in
  btrfs_find_orphan_roots()
have their orphan items, so it is unnecessary to check the orphan
item again.

So cleanup it.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

1 files changed, 11 insertions, 2 deletions

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 24940085cdac..440de708f9eb 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -5367,7 +5367,6 @@ static struct btrfs_device *add_missing_dev(struct btrfs_root *root,
                 return NULL;
         list_add(&device->dev_list,
                  &fs_devices->devices);
-        device->dev_root = root->fs_info->dev_root;
         device->devid = devid;
         device->work.func = pending_bios_fn;
         device->fs_devices = fs_devices;
@@ -5593,7 +5592,6 @@ static int read_one_dev(struct btrfs_root *root,
         }
 
         fill_device_from_item(leaf, dev_item, device);
-        device->dev_root = root->fs_info->dev_root;
         device->in_fs_metadata = 1;
         if (device->writeable && !device->is_tgtdev_for_dev_replace) {
                 device->fs_devices->total_rw_bytes += device->total_bytes;
@@ -5751,6 +5749,17 @@ error:
         return ret;
 }
 
+void btrfs_init_devices_late(struct btrfs_fs_info *fs_info)
+{
+        struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
+        struct btrfs_device *device;
+
+        mutex_lock(&fs_devices->device_list_mutex);
+        list_for_each_entry(device, &fs_devices->devices, dev_list)
+                device->dev_root = fs_info->dev_root;
+        mutex_unlock(&fs_devices->device_list_mutex);
+}
+
 static void __btrfs_reset_dev_stats(struct btrfs_device *dev)
 {
         int i;