clear RCU on all failure exits from link_path_walk()

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

1 files changed, 16 insertions, 14 deletions

diff --git a/fs/namei.c b/fs/namei.c
index d29f91e8ff3d..f09887a45831 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1405,8 +1405,9 @@ static int link_path_walk(const char *name, struct nameidata *nd)
                  * parent relationships.
                  */
                 if (unlikely(type != LAST_NORM)) {
-                        if (handle_dots(nd, type))
-                                return -ECHILD;
+                        err = handle_dots(nd, type);
+                        if (err)
+                                goto return_err;
                         continue;
                 }
 
@@ -1441,8 +1442,9 @@ last_component:
                 if (lookup_flags & LOOKUP_PARENT)
                         goto lookup_parent;
                 if (unlikely(type != LAST_NORM)) {
-                        if (handle_dots(nd, type))
-                                return -ECHILD;
+                        err = handle_dots(nd, type);
+                        if (err)
+                                goto return_err;
                         return 0;
                 }
                 err = do_lookup(nd, &this, &next, &inode);
@@ -1475,6 +1477,12 @@ lookup_parent:
         if (!(nd->flags & LOOKUP_RCU))
                 path_put(&nd->path);
 return_err:
+        if (nd->flags & LOOKUP_RCU) {
+                nd->flags &= ~LOOKUP_RCU;
+                nd->root.mnt = NULL;
+                rcu_read_unlock();
+                br_read_unlock(vfsmount_lock);
+        }
         return err;
 }
 
@@ -1585,16 +1593,10 @@ static int path_lookupat(int dfd, const char *name,
         retval = link_path_walk(name, nd);
 
         if (nd->flags & LOOKUP_RCU) {
-                /* RCU dangling. Cancel it. */
-                if (!retval) {
-                        if (nameidata_drop_rcu_last(nd))
-                                retval = -ECHILD;
-                } else {
-                        nd->flags &= ~LOOKUP_RCU;
-                        nd->root.mnt = NULL;
-                        rcu_read_unlock();
-                        br_read_unlock(vfsmount_lock);
-                }
+                /* went all way through without dropping RCU */
+                BUG_ON(retval);
+                if (nameidata_drop_rcu_last(nd))
+                        retval = -ECHILD;
         }
 
         if (!retval)