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);
 }