1 files changed, 27 insertions, 11 deletions

diff --git a/fs/dcookies.c b/fs/dcookies.c
index 855d4b1d619a..a21cabdbd87b 100644
--- a/fs/dcookies.c
+++ b/fs/dcookies.c
@@ -93,10 +93,15 @@ static struct dcookie_struct *alloc_dcookie(struct path *path)
 {
 	struct dcookie_struct *dcs = kmem_cache_alloc(dcookie_cache,
 							GFP_KERNEL);
+	struct dentry *d;
 	if (!dcs)
 		return NULL;
 
-	path->dentry->d_cookie = dcs;
+	d = path->dentry;
+	spin_lock(&d->d_lock);
+	d->d_flags |= DCACHE_COOKIE;
+	spin_unlock(&d->d_lock);
+
 	dcs->path = *path;
 	path_get(path);
 	hash_dcookie(dcs);
@@ -119,14 +124,14 @@ int get_dcookie(struct path *path, unsigned long *cookie)
 		goto out;
 	}
 
-	dcs = path->dentry->d_cookie;
-
-	if (!dcs)
+	if (path->dentry->d_flags & DCACHE_COOKIE) {
+		dcs = find_dcookie((unsigned long)path->dentry);
+	} else {
 		dcs = alloc_dcookie(path);
-
-	if (!dcs) {
-		err = -ENOMEM;
-		goto out;
+		if (!dcs) {
+			err = -ENOMEM;
+			goto out;
+		}
 	}
 
 	*cookie = dcookie_value(dcs);
@@ -140,7 +145,7 @@ out:
 /* And here is where the userspace process can look up the cookie value
  * to retrieve the path.
  */
-asmlinkage long sys_lookup_dcookie(u64 cookie64, char __user * buf, size_t len)
+SYSCALL_DEFINE(lookup_dcookie)(u64 cookie64, char __user * buf, size_t len)
 {
 	unsigned long cookie = (unsigned long)cookie64;
 	int err = -EINVAL;
@@ -193,7 +198,13 @@ out:
 	mutex_unlock(&dcookie_mutex);
 	return err;
 }
-
+#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
+asmlinkage long SyS_lookup_dcookie(u64 cookie64, long buf, long len)
+{
+	return SYSC_lookup_dcookie(cookie64, (char __user *) buf, (size_t) len);
+}
+SYSCALL_ALIAS(sys_lookup_dcookie, SyS_lookup_dcookie);
+#endif
 
 static int dcookie_init(void)
 {
@@ -251,7 +262,12 @@ out_kmem:
 
 static void free_dcookie(struct dcookie_struct * dcs)
 {
-	dcs->path.dentry->d_cookie = NULL;
+	struct dentry *d = dcs->path.dentry;
+
+	spin_lock(&d->d_lock);
+	d->d_flags &= ~DCACHE_COOKIE;
+	spin_unlock(&d->d_lock);
+
 	path_put(&dcs->path);
 	kmem_cache_free(dcookie_cache, dcs);
 }