get rid of the last LOOKUP_RCU dependencies in link_path_walk()

New helper: terminate_walk().  An error has happened during pathname
resolution and we either drop nd->path or terminate RCU, depending
the mode we had been in.  After that, nd is essentially empty.
Switch link_path_walk() to using that for cleanup.

Now the top-level logics in link_path_walk() is back to sanity.  RCU
dependencies are in the lower-level functions.

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

1 files changed, 13 insertions, 8 deletions

diff --git a/fs/namei.c b/fs/namei.c
index 53bba7c1a520..85f6e39b4034 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1343,6 +1343,18 @@ static inline int handle_dots(struct nameidata *nd, int type)
         return 0;
 }
 
+static void terminate_walk(struct nameidata *nd)
+{
+        if (!(nd->flags & LOOKUP_RCU)) {
+                path_put(&nd->path);
+        } else {
+                nd->flags &= ~LOOKUP_RCU;
+                nd->root.mnt = NULL;
+                rcu_read_unlock();
+                br_read_unlock(vfsmount_lock);
+        }
+}
+
 /*
  * Name resolution.
  * This is the basic name resolution function, turning a pathname into
@@ -1482,14 +1494,7 @@ lookup_parent:
                 nd->last_type = type;
                 return 0;
         }
-        if (!(nd->flags & LOOKUP_RCU))
-                path_put(&nd->path);
-        if (nd->flags & LOOKUP_RCU) {
-                nd->flags &= ~LOOKUP_RCU;
-                nd->root.mnt = NULL;
-                rcu_read_unlock();
-                br_read_unlock(vfsmount_lock);
-        }
+        terminate_walk(nd);
         return err;
 }