Commit 38f48850 authored by Al Viro's avatar Al Viro
Browse files

mnt_ns_tree_remove(): DTRT if mnt_ns had never been added to mnt_ns_list 



Actual removal is done under the lock, but for checking if need to bother
the lockless RB_EMPTY_NODE() is safe - either that namespace had never
been added to mnt_ns_tree, in which case the the node will stay empty, or
whoever had allocated it has called mnt_ns_tree_add() and it has already
run to completion.  After that point RB_EMPTY_NODE() will become false and
will remain false, no matter what we do with other nodes in the tree.

Reviewed-by: default avatarChristian Brauner <brauner@kernel.org>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent b320789d

fs/namespace.c

+1 −1
Original line number Diff line number Diff line
@@ -187,7 +187,7 @@ static void mnt_ns_release_rcu(struct rcu_head *rcu) 
static void mnt_ns_tree_remove(struct mnt_namespace *ns)

{

	/* remove from global mount namespace list */

	if (!is_anon_ns(ns)) {

	if (!RB_EMPTY_NODE(&ns->mnt_ns_tree_node)) {

		mnt_ns_tree_write_lock();

		rb_erase(&ns->mnt_ns_tree_node, &mnt_ns_tree);

		list_bidir_del_rcu(&ns->mnt_ns_list);