btrfs: factor out sysfs code for updating sprout fsid

Wrap the fsid renaming code and move it to sysfs.c.
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/sysfs.c

@@ -946,6 +946,21 @@ void btrfs_kobject_uevent(struct block_device *bdev, enum kobject_action action)
 			&disk_to_dev(bdev->bd_disk)->kobj);
 }
 
+void btrfs_sysfs_update_sprout_fsid(struct btrfs_fs_devices *fs_devices,
+				    const u8 *fsid)
+{
+	char fsid_buf[BTRFS_UUID_UNPARSED_SIZE];
+
+	/*
+	 * Sprouting changes fsid of the mounted filesystem, rename the fsid
+	 * directory
+	 */
+	snprintf(fsid_buf, BTRFS_UUID_UNPARSED_SIZE, "%pU", fsid);
+	if (kobject_rename(&fs_devices->fsid_kobj, fsid_buf))
+		btrfs_warn(fs_devices->fs_info,
+				"sysfs: failed to create fsid for sprout");
+}
+
 /* /sys/fs/btrfs/ entry */
 static struct kset *btrfs_kset;
 

fs/btrfs/sysfs.h

@@ -87,6 +87,8 @@ int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs,
 				struct kobject *parent);
 int btrfs_sysfs_add_device(struct btrfs_fs_devices *fs_devs);
 void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs);
+void btrfs_sysfs_update_sprout_fsid(struct btrfs_fs_devices *fs_devices,
+				    const u8 *fsid);
 void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info,
 		u64 bit, enum btrfs_feature_set set);
 void btrfs_kobject_uevent(struct block_device *bdev, enum kobject_action action);

fs/btrfs/volumes.c

@@ -2680,22 +2680,14 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path
 	}
 
 	if (seeding_dev) {
-		char fsid_buf[BTRFS_UUID_UNPARSED_SIZE];
-
 		ret = btrfs_finish_sprout(trans);
 		if (ret) {
 			btrfs_abort_transaction(trans, ret);
 			goto error_sysfs;
 		}
 
-		/* Sprouting would change fsid of the mounted root,
-		 * so rename the fsid on the sysfs
-		 */
-		snprintf(fsid_buf, BTRFS_UUID_UNPARSED_SIZE, "%pU",
+		btrfs_sysfs_update_sprout_fsid(fs_devices,
 				fs_info->fs_devices->fsid);
-		if (kobject_rename(&fs_devices->fsid_kobj, fsid_buf))
-			btrfs_warn(fs_info,
-				   "sysfs: failed to create fsid for sprout");
 	}
 
 	ret = btrfs_commit_transaction(trans);