namei: lift nameidata into filename_mountpoint()

when we go for on-demand allocation of saved state in
link_path_walk(), we'll want nameidata to stay around
for all 3 calls of path_mountpoint().

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

diff --git a/fs/namei.c b/fs/namei.c
index 293300c..ab2bcbd 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2344,31 +2344,28 @@ out:
  */
 static int
 path_mountpoint(int dfd, const struct filename *name, struct path *path,
-               unsigned int flags)
+               struct nameidata *nd, unsigned int flags)
 {
-       struct nameidata nd;
-       int err;
-
-       err = path_init(dfd, name, flags, &nd);
+       int err = path_init(dfd, name, flags, nd);
        if (unlikely(err))
                goto out;
 
-       err = mountpoint_last(&nd, path);
+       err = mountpoint_last(nd, path);
        while (err > 0) {
                void *cookie;
                struct path link = *path;
-               err = may_follow_link(&link, &nd);
+               err = may_follow_link(&link, nd);
                if (unlikely(err))
                        break;
-               nd.flags |= LOOKUP_PARENT;
-               err = follow_link(&link, &nd, &cookie);
+               nd->flags |= LOOKUP_PARENT;
+               err = follow_link(&link, nd, &cookie);
                if (err)
                        break;
-               err = mountpoint_last(&nd, path);
-               put_link(&nd, &link, cookie);
+               err = mountpoint_last(nd, path);
+               put_link(nd, &link, cookie);
        }
 out:
-       path_cleanup(&nd);
+       path_cleanup(nd);
        return err;
 }
 
@@ -2376,14 +2373,15 @@ static int
 filename_mountpoint(int dfd, struct filename *name, struct path *path,
                        unsigned int flags)
 {
+       struct nameidata nd;
        int error;
        if (IS_ERR(name))
                return PTR_ERR(name);
-       error = path_mountpoint(dfd, name, path, flags | LOOKUP_RCU);
+       error = path_mountpoint(dfd, name, path, &nd, flags | LOOKUP_RCU);
        if (unlikely(error == -ECHILD))
-               error = path_mountpoint(dfd, name, path, flags);
+               error = path_mountpoint(dfd, name, path, &nd, flags);
        if (unlikely(error == -ESTALE))
-               error = path_mountpoint(dfd, name, path, flags | LOOKUP_REVAL);
+               error = path_mountpoint(dfd, name, path, &nd, flags | LOOKUP_REVAL);
        if (likely(!error))
                audit_inode(name, path->dentry, 0);
        putname(name);