nilfs2: add support for FS_IOC_GETFSSYSFSPATH

Use the standard helper super_set_sysfs_name_bdev() to give the sysfs
subpath of the filesystem for the FS_IOC_GETFSSYSFSPATH ioctl.

For nilfs2, it will output "nilfs2/<dev>".

Link: https://lkml.kernel.org/r/20240815074408.5550-3-konishi.ryusuke@gmail.comSigned-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/nilfs2/super.c

@@ -1065,6 +1065,7 @@ nilfs_fill_super(struct super_block *sb, struct fs_context *fc)
 
 	super_set_uuid(sb, nilfs->ns_sbp[0]->s_uuid,
 		       sizeof(nilfs->ns_sbp[0]->s_uuid));
+	super_set_sysfs_name_bdev(sb);
 
 	cno = nilfs_last_cno(nilfs);
 	err = nilfs_attach_checkpoint(sb, cno, true, &fsroot);