btrfs: make btrfs_check_uuid_tree private to disk-io.c

It's used only during filesystem mount as such it can be made private to
disk-io.c file. Also use the occasion to move btrfs_uuid_rescan_kthread
as btrfs_check_uuid_tree is its sole caller.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/disk-io.c

@@ -2835,6 +2835,41 @@ static int init_mount_fs_info(struct btrfs_fs_info *fs_info, struct super_block
 	return ret;
 }
 
+static int btrfs_uuid_rescan_kthread(void *data)
+{
+	struct btrfs_fs_info *fs_info = (struct btrfs_fs_info *)data;
+	int ret;
+
+	/*
+	 * 1st step is to iterate through the existing UUID tree and
+	 * to delete all entries that contain outdated data.
+	 * 2nd step is to add all missing entries to the UUID tree.
+	 */
+	ret = btrfs_uuid_tree_iterate(fs_info);
+	if (ret < 0) {
+		btrfs_warn(fs_info, "iterating uuid_tree failed %d", ret);
+		up(&fs_info->uuid_tree_rescan_sem);
+		return ret;
+	}
+	return btrfs_uuid_scan_kthread(data);
+}
+
+static int btrfs_check_uuid_tree(struct btrfs_fs_info *fs_info)
+{
+	struct task_struct *task;
+
+	down(&fs_info->uuid_tree_rescan_sem);
+	task = kthread_run(btrfs_uuid_rescan_kthread, fs_info, "btrfs-uuid");
+	if (IS_ERR(task)) {
+		/* fs_info->update_uuid_tree_gen remains 0 in all error case */
+		btrfs_warn(fs_info, "failed to start uuid_rescan task");
+		up(&fs_info->uuid_tree_rescan_sem);
+		return PTR_ERR(task);
+	}
+
+	return 0;
+}
+
 int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_devices,
 		      char *options)
 {

fs/btrfs/volumes.c

@@ -4313,7 +4313,7 @@ int btrfs_cancel_balance(struct btrfs_fs_info *fs_info)
 	return 0;
 }
 
-static int btrfs_uuid_scan_kthread(void *data)
+int btrfs_uuid_scan_kthread(void *data)
 {
 	struct btrfs_fs_info *fs_info = data;
 	struct btrfs_root *root = fs_info->tree_root;
@@ -4442,25 +4442,6 @@ static int btrfs_uuid_scan_kthread(void *data)
 	return 0;
 }
 
-static int btrfs_uuid_rescan_kthread(void *data)
-{
-	struct btrfs_fs_info *fs_info = (struct btrfs_fs_info *)data;
-	int ret;
-
-	/*
-	 * 1st step is to iterate through the existing UUID tree and
-	 * to delete all entries that contain outdated data.
-	 * 2nd step is to add all missing entries to the UUID tree.
-	 */
-	ret = btrfs_uuid_tree_iterate(fs_info);
-	if (ret < 0) {
-		btrfs_warn(fs_info, "iterating uuid_tree failed %d", ret);
-		up(&fs_info->uuid_tree_rescan_sem);
-		return ret;
-	}
-	return btrfs_uuid_scan_kthread(data);
-}
-
 int btrfs_create_uuid_tree(struct btrfs_fs_info *fs_info)
 {
 	struct btrfs_trans_handle *trans;
@@ -4503,22 +4484,6 @@ int btrfs_create_uuid_tree(struct btrfs_fs_info *fs_info)
 	return 0;
 }
 
-int btrfs_check_uuid_tree(struct btrfs_fs_info *fs_info)
-{
-	struct task_struct *task;
-
-	down(&fs_info->uuid_tree_rescan_sem);
-	task = kthread_run(btrfs_uuid_rescan_kthread, fs_info, "btrfs-uuid");
-	if (IS_ERR(task)) {
-		/* fs_info->update_uuid_tree_gen remains 0 in all error case */
-		btrfs_warn(fs_info, "failed to start uuid_rescan task");
-		up(&fs_info->uuid_tree_rescan_sem);
-		return PTR_ERR(task);
-	}
-
-	return 0;
-}
-
 /*
  * shrinking a device means finding all of the device extents past
  * the new size, and then following the back refs to the chunks.

fs/btrfs/volumes.h

@@ -459,7 +459,7 @@ int btrfs_recover_balance(struct btrfs_fs_info *fs_info);
 int btrfs_pause_balance(struct btrfs_fs_info *fs_info);
 int btrfs_cancel_balance(struct btrfs_fs_info *fs_info);
 int btrfs_create_uuid_tree(struct btrfs_fs_info *fs_info);
-int btrfs_check_uuid_tree(struct btrfs_fs_info *fs_info);
+int btrfs_uuid_scan_kthread(void *data);
 int btrfs_chunk_readonly(struct btrfs_fs_info *fs_info, u64 chunk_offset);
 int find_free_dev_extent(struct btrfs_device *device, u64 num_bytes,
 			 u64 *start, u64 *max_avail);