bpf, inode_storage: Put file handler if no storage was found

Put file f if inode_storage_ptr() returns NULL.

Fixes: 8ea636848a ("bpf: Implement bpf_local_storage for inodes")
Signed-off-by: Pan Bian <bianpan2016@163.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: KP Singh <kpsingh@kernel.org>
Link: https://lore.kernel.org/bpf/20210121020856.25507-1-bianpan2016@163.com

kernel/bpf/bpf_inode_storage.c

@@ -125,8 +125,12 @@ static int bpf_fd_inode_storage_update_elem(struct bpf_map *map, void *key,
 
 	fd = *(int *)key;
 	f = fget_raw(fd);
-	if (!f || !inode_storage_ptr(f->f_inode))
+	if (!f)
 		return -EBADF;
+	if (!inode_storage_ptr(f->f_inode)) {
+		fput(f);
+		return -EBADF;
+	}
 
 	sdata = bpf_local_storage_update(f->f_inode,
 					 (struct bpf_local_storage_map *)map,