drop out of RCU in return_reval

... thus killing the need to handle drop-from-RCU in d_revalidate()

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

1 files changed, 6 insertions, 19 deletions

diff --git a/fs/namei.c b/fs/namei.c
index a98f7f141780..10635d329175 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -571,25 +571,9 @@ void release_open_intent(struct nameidata *nd)
         }
 }
 
-/*
- * Call d_revalidate and handle filesystems that request rcu-walk
- * to be dropped. This may be called and return in rcu-walk mode,
- * regardless of success or error. If -ECHILD is returned, the caller
- * must return -ECHILD back up the path walk stack so path walk may
- * be restarted in ref-walk mode.
- */
-static int d_revalidate(struct dentry *dentry, struct nameidata *nd)
+static inline int d_revalidate(struct dentry *dentry, struct nameidata *nd)
 {
-        int status;
-
-        status = dentry->d_op->d_revalidate(dentry, nd);
-        if (status == -ECHILD) {
-                if (nameidata_dentry_drop_rcu(nd, dentry))
-                        return status;
-                status = dentry->d_op->d_revalidate(dentry, nd);
-        }
-
-        return status;
+        return dentry->d_op->d_revalidate(dentry, nd);
 }
 
 static struct dentry *
@@ -617,7 +601,7 @@ do_revalidate(struct dentry *dentry, struct nameidata *nd)
 static inline struct dentry *
 do_revalidate_rcu(struct dentry *dentry, struct nameidata *nd)
 {
-        int status = dentry->d_op->d_revalidate(dentry, nd);
+        int status = d_revalidate(dentry, nd);
         if (likely(status > 0))
                 return dentry;
         if (status == -ECHILD) {
@@ -1517,12 +1501,15 @@ return_reval:
                  * We may need to check the cached dentry for staleness.
                  */
                 if (need_reval_dot(nd->path.dentry)) {
+                        if (nameidata_drop_rcu_last_maybe(nd))
+                                return -ECHILD;
                         /* Note: we do not d_invalidate() */
                         err = d_revalidate(nd->path.dentry, nd);
                         if (!err)
                                 err = -ESTALE;
                         if (err < 0)
                                 break;
+                        return 0;
                 }
 return_base:
                 if (nameidata_drop_rcu_last_maybe(nd))