From 1dc432094af8212842e513ff7360f25b5d3ee1da Mon Sep 17 00:00:00 2001
From: Nick Piggin <npiggin@kernel.dk>
Date: Fri, 7 Jan 2011 17:49:59 +1100
Subject: [PATCH] --- yaml --- r: 226731 b: refs/heads/master c:
 1e1743ebe35ec7e3c1fa732408358fbc614cbbe5 h: refs/heads/master i:   226729:
 9322819a85492ec5f24d4e70041a0851c9c8ad64   226727:
 ab777f0dc4d967e1c1852cf53cd2aa3e9d22a5a4 v: v3

---
 [refs]                          |  2 +-
 trunk/fs/generic_acl.c          | 22 ++++++++++++----------
 trunk/include/linux/posix_acl.h | 19 +++++++++++++++++++
 3 files changed, 32 insertions(+), 11 deletions(-)

diff --git a/[refs] b/[refs]
index 222100d67923..be0439a78d9d 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: b74c79e99389cd79b31fcc08f82c24e492e63c7e
+refs/heads/master: 1e1743ebe35ec7e3c1fa732408358fbc614cbbe5
diff --git a/trunk/fs/generic_acl.c b/trunk/fs/generic_acl.c
index 628004282130..06c48a891832 100644
--- a/trunk/fs/generic_acl.c
+++ b/trunk/fs/generic_acl.c
@@ -192,16 +192,18 @@ generic_acl_chmod(struct inode *inode)
 int
 generic_check_acl(struct inode *inode, int mask, unsigned int flags)
 {
-	struct posix_acl *acl;
-
-	if (flags & IPERM_FLAG_RCU)
-		return -ECHILD;
-
-	acl = get_cached_acl(inode, ACL_TYPE_ACCESS);
-	if (acl) {
-		int error = posix_acl_permission(inode, acl, mask);
-		posix_acl_release(acl);
-		return error;
+	if (flags & IPERM_FLAG_RCU) {
+		if (!negative_cached_acl(inode, ACL_TYPE_ACCESS))
+			return -ECHILD;
+	} else {
+		struct posix_acl *acl;
+
+		acl = get_cached_acl(inode, ACL_TYPE_ACCESS);
+		if (acl) {
+			int error = posix_acl_permission(inode, acl, mask);
+			posix_acl_release(acl);
+			return error;
+		}
 	}
 	return -EAGAIN;
 }
diff --git a/trunk/include/linux/posix_acl.h b/trunk/include/linux/posix_acl.h
index 67608161df6b..d68283a898bb 100644
--- a/trunk/include/linux/posix_acl.h
+++ b/trunk/include/linux/posix_acl.h
@@ -108,6 +108,25 @@ static inline struct posix_acl *get_cached_acl(struct inode *inode, int type)
 	return acl;
 }
 
+static inline int negative_cached_acl(struct inode *inode, int type)
+{
+	struct posix_acl **p, *acl;
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		p = &inode->i_acl;
+		break;
+	case ACL_TYPE_DEFAULT:
+		p = &inode->i_default_acl;
+		break;
+	default:
+		BUG();
+	}
+	acl = ACCESS_ONCE(*p);
+	if (acl)
+		return 0;
+	return 1;
+}
+
 static inline void set_cached_acl(struct inode *inode,
 				  int type,
 				  struct posix_acl *acl)