nothing in do_follow_link() is going to see RCU (844a3917) · Commits · e / devices / android_kernel_fairphone_FP3

fs/namei.c

+7 −8

Original line number	Diff line number	Diff line
		@@ -668,9 +668,6 @@ force_reval_path(struct path path, struct nameidata nd)
		return 0;

		if (!status) {
		/* Don't d_invalidate in rcu-walk mode */
		if (nameidata_drop_rcu(nd))
		return -ECHILD;
		d_invalidate(dentry);
		status = -ESTALE;
		}
		@@ -777,6 +774,8 @@ __do_follow_link(const struct path link, struct nameidata nd, void **p)
		int error;
		struct dentry *dentry = link->dentry;

		BUG_ON(nd->flags & LOOKUP_RCU);

		touch_atime(link->mnt, dentry);
		nd_set_link(nd, NULL);

		@@ -811,6 +810,11 @@ static inline int do_follow_link(struct path path, struct nameidata nd)
		{
		void *cookie;
		int err = -ELOOP;

		/* We drop rcu-walk here */
		if (nameidata_dentry_drop_rcu_maybe(nd, path->dentry))
		return -ECHILD;

		if (current->link_count >= MAX_NESTED_LINKS)
		goto loop;
		if (current->total_link_count >= 40)
		@@ -1419,9 +1423,6 @@ static int link_path_walk(const char name, struct nameidata nd)
		goto out_dput;

		if (inode->i_op->follow_link) {
		/* We commonly drop rcu-walk here */
		if (nameidata_dentry_drop_rcu_maybe(nd, next.dentry))
		return -ECHILD;
		BUG_ON(inode != next.dentry->d_inode);
		err = do_follow_link(&next, nd);
		if (err)
		@@ -1467,8 +1468,6 @@ static int link_path_walk(const char name, struct nameidata nd)
		break;
		if (inode && unlikely(inode->i_op->follow_link) &&
		(lookup_flags & LOOKUP_FOLLOW)) {
		if (nameidata_dentry_drop_rcu_maybe(nd, next.dentry))
		return -ECHILD;
		BUG_ON(inode != next.dentry->d_inode);
		err = do_follow_link(&next, nd);
		if (err)