diff --git a/fs/ioctl.c b/fs/ioctl.c
index 2005529af560..0400297c8d72 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -669,6 +669,9 @@ int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
 		return ioctl_fiemap(filp, arg);
 
 	case FIGETBSZ:
+		/* anon_bdev filesystems may not have a block size */
+		if (!inode->i_sb->s_blocksize)
+			return -EINVAL;
 		return put_user(inode->i_sb->s_blocksize, argp);
 
 	case FICLONE: