autofs_clear_leaf_automount_flags(): use ino->count instead of ->d_subdirs (e509d6e9) · Commits · 戴 / test

We want to find out if the parent will become empty after we remove the victim of rmdir(). Checking if the victim is the only element of parent's ->d_subdirs is completely wrong - e.g. opening the parent will end up with a cursor added to its ->d_parent and fooling the check. We do maintain ino->count - 0 for anything removed, 1 + number of children for anything live. Which gives us precisely what we need for that check... Signed-off-by:

Al Viro <viro@zeniv.linux.org.uk>

fs/autofs/root.c

+1 −5

Original line number	Diff line number	Diff line
		@@ -660,7 +660,6 @@ static void autofs_set_leaf_automount_flags(struct dentry *dentry)

		static void autofs_clear_leaf_automount_flags(struct dentry *dentry)
		{
		struct list_head *d_child;
		struct dentry *parent;

		/* flags for dentrys in the root are handled elsewhere */
		@@ -673,10 +672,7 @@ static void autofs_clear_leaf_automount_flags(struct dentry *dentry)
		/* only consider parents below dentrys in the root */
		if (IS_ROOT(parent->d_parent))
		return;
		d_child = &dentry->d_child;
		/* Set parent managed if it's becoming empty */
		if (d_child->next == &parent->d_subdirs &&
		d_child->prev == &parent->d_subdirs)
		if (atomic_read(&autofs_dentry_ino(parent)->count) == 2)
		managed_dentry_set_managed(parent);
		}

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