split the slow part of lock_parent() off

Turn the "trylock failed" part into uninlined __lock_parent().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 12 insertions, 6 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index 916fd57b9d18..61819fb32e13 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -588,13 +588,9 @@ static void __dentry_kill(struct dentry *dentry)
                 dentry_free(dentry);
 }
 
-static inline struct dentry *lock_parent(struct dentry *dentry)
+static struct dentry *__lock_parent(struct dentry *dentry)
 {
-        struct dentry *parent = dentry->d_parent;
-        if (IS_ROOT(dentry))
-                return NULL;
-        if (likely(spin_trylock(&parent->d_lock)))
-                return parent;
+        struct dentry *parent;
         rcu_read_lock();
         spin_unlock(&dentry->d_lock);
 again:
@@ -620,6 +616,16 @@ again:
         return parent;
 }
 
+static inline struct dentry *lock_parent(struct dentry *dentry)
+{
+        struct dentry *parent = dentry->d_parent;
+        if (IS_ROOT(dentry))
+                return NULL;
+        if (likely(spin_trylock(&parent->d_lock)))
+                return parent;
+        return __lock_parent(dentry);
+}
+
 /*
  * Finish off a dentry we've decided to kill.
  * dentry->d_lock must be held, returns with it unlocked.