From 2391618e08f43e2d64013ac9a32e3cc7fa45e92c Mon Sep 17 00:00:00 2001
From: Nick Piggin <npiggin@kernel.dk>
Date: Fri, 7 Jan 2011 17:49:45 +1100
Subject: [PATCH] --- yaml --- r: 226717 b: refs/heads/master c:
 89e6054836a7b1e7500cd70a14b5579e752c9250 h: refs/heads/master i:   226715:
 f10692791b6459ee3a3d88a78e09617e254aad1e v: v3

---
 [refs]            |  2 +-
 trunk/fs/dcache.c | 27 +++++++++++++++------------
 2 files changed, 16 insertions(+), 13 deletions(-)

diff --git a/[refs] b/[refs]
index 1a8da51dd54d..93c6a7461a73 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: a734eb458ab2bd11479a27dd54f48e1b26a55845
+refs/heads/master: 89e6054836a7b1e7500cd70a14b5579e752c9250
diff --git a/trunk/fs/dcache.c b/trunk/fs/dcache.c
index a8f89765d602..195706374697 100644
--- a/trunk/fs/dcache.c
+++ b/trunk/fs/dcache.c
@@ -582,26 +582,29 @@ static void prune_one_dentry(struct dentry *dentry, struct dentry *parent)
 	 * Prune ancestors.
 	 */
 	while (dentry) {
-		spin_lock(&dcache_inode_lock);
-again:
+relock:
 		spin_lock(&dentry->d_lock);
+		if (dentry->d_count > 1) {
+			dentry->d_count--;
+			spin_unlock(&dentry->d_lock);
+			return;
+		}
+		if (!spin_trylock(&dcache_inode_lock)) {
+relock2:
+			spin_unlock(&dentry->d_lock);
+			cpu_relax();
+			goto relock;
+		}
+
 		if (IS_ROOT(dentry))
 			parent = NULL;
 		else
 			parent = dentry->d_parent;
 		if (parent && !spin_trylock(&parent->d_lock)) {
-			spin_unlock(&dentry->d_lock);
-			goto again;
-		}
-		dentry->d_count--;
-		if (dentry->d_count) {
-			if (parent)
-				spin_unlock(&parent->d_lock);
-			spin_unlock(&dentry->d_lock);
 			spin_unlock(&dcache_inode_lock);
-			return;
+			goto relock2;
 		}
-
+		dentry->d_count--;
 		dentry_lru_del(dentry);
 		__d_drop(dentry);
 		dentry = d_kill(dentry, parent);