nothing in do_follow_link() is going to see RCU

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

1 files changed, 7 insertions, 8 deletions

diff --git a/fs/namei.c b/fs/namei.c
index ec4b2d0190a8..9ce6d272f4f2 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -668,9 +668,6 @@ force_reval_path(struct path *path, struct nameidata *nd)
                 return 0;
 
         if (!status) {
-                /* Don't d_invalidate in rcu-walk mode */
-                if (nameidata_drop_rcu(nd))
-                        return -ECHILD;
                 d_invalidate(dentry);
                 status = -ESTALE;
         }
@@ -777,6 +774,8 @@ __do_follow_link(const struct path *link, struct nameidata *nd, void **p)
         int error;
         struct dentry *dentry = link->dentry;
 
+        BUG_ON(nd->flags & LOOKUP_RCU);
+
         touch_atime(link->mnt, dentry);
         nd_set_link(nd, NULL);
 
@@ -811,6 +810,11 @@ static inline int do_follow_link(struct path *path, struct nameidata *nd)
 {
         void *cookie;
         int err = -ELOOP;
+
+        /* We drop rcu-walk here */
+        if (nameidata_dentry_drop_rcu_maybe(nd, path->dentry))
+                return -ECHILD;
+
         if (current->link_count >= MAX_NESTED_LINKS)
                 goto loop;
         if (current->total_link_count >= 40)
@@ -1419,9 +1423,6 @@ exec_again:
                         goto out_dput;
 
                 if (inode->i_op->follow_link) {
-                        /* We commonly drop rcu-walk here */
-                        if (nameidata_dentry_drop_rcu_maybe(nd, next.dentry))
-                                return -ECHILD;
                         BUG_ON(inode != next.dentry->d_inode);
                         err = do_follow_link(&next, nd);
                         if (err)
@@ -1467,8 +1468,6 @@ last_component:
                         break;
                 if (inode && unlikely(inode->i_op->follow_link) &&
                     (lookup_flags & LOOKUP_FOLLOW)) {
-                        if (nameidata_dentry_drop_rcu_maybe(nd, next.dentry))
-                                return -ECHILD;
                         BUG_ON(inode != next.dentry->d_inode);
                         err = do_follow_link(&next, nd);
                         if (err)