Commit c14cc63a authored Jan 18, 2011 by Ian Kent Committed by Al Viro Jan 18, 2011

autofs4 - fix get_next_positive_dentry()



The initialization condition in fs/autofs4/expire.c:get_next_positive_dentry()
appears to be incorrect. If prev == NULL I believe that root should be
returned.

Further down, at the current dentry check for it being simple_positive()
it looks like the d_lock for dentry p should be dropped instead of dentry
ret, otherwise when p is assinged to ret we end up with no lock on p and
a lost lock on ret, which leads to a deadlock.

Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

parent 6845a44a

fs/autofs4/expire.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -96,7 +96,7 @@ static struct dentry get_next_positive_dentry(struct dentry prev,
		struct dentry p, ret;

		if (prev == NULL)
		return dget(prev);
		return dget(root);

		spin_lock(&autofs4_lock);
		relock:
		@@ -133,7 +133,7 @@ again:
		spin_lock_nested(&ret->d_lock, DENTRY_D_LOCK_NESTED);
		/* Negative dentry - try next */
		if (!simple_positive(ret)) {
		spin_unlock(&ret->d_lock);
		spin_unlock(&p->d_lock);
		p = ret;
		goto again;
		}