Merge branch 'work.audit' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull RCU-safe common_lsm_audit() from Al Viro:
 "Make common_lsm_audit() non-blocking and usable from RCU pathwalk
  context.

  We don't really need to grab/drop dentry in there - rcu_read_lock() is
  enough. There's a couple of followups using that to simplify the
  logics in selinux, but those hadn't soaked in -next yet, so they'll
  have to go in next window"

* 'work.audit' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  make dump_common_audit_data() safe to be called from RCU pathwalk
  new helper: d_find_alias_rcu()

1 files changed, 25 insertions, 0 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index c17fd15b01d4..799d9e4f0bcd 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1044,6 +1044,31 @@ struct dentry *d_find_alias(struct inode *inode)
 EXPORT_SYMBOL(d_find_alias);
 
 /*
+ *  Caller MUST be holding rcu_read_lock() and be guaranteed
+ *  that inode won't get freed until rcu_read_unlock().
+ */
+struct dentry *d_find_alias_rcu(struct inode *inode)
+{
+	struct hlist_head *l = &inode->i_dentry;
+	struct dentry *de = NULL;
+
+	spin_lock(&inode->i_lock);
+	// ->i_dentry and ->i_rcu are colocated, but the latter won't be
+	// used without having I_FREEING set, which means no aliases left
+	if (likely(!(inode->i_state & I_FREEING) && !hlist_empty(l))) {
+		if (S_ISDIR(inode->i_mode)) {
+			de = hlist_entry(l->first, struct dentry, d_u.d_alias);
+		} else {
+			hlist_for_each_entry(de, l, d_u.d_alias)
+				if (!d_unhashed(de))
+					break;
+		}
+	}
+	spin_unlock(&inode->i_lock);
+	return de;
+}
+
+/*
  *	Try to kill dentries associated with this inode.
  * WARNING: you must own a reference to inode.
  */