namei: shift nameidata inside filename_lookup()

pass root instead; non-NULL => copy to nd.root and
set LOOKUP_ROOT in flags

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

1 files changed, 14 insertions, 16 deletions

diff --git a/fs/namei.c b/fs/namei.c
index 847c61a48078..2999404c8d30 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2119,17 +2119,20 @@ static int path_lookupat(int dfd, const struct filename *name, unsigned flags,
 }
 
 static int filename_lookup(int dfd, struct filename *name, unsigned flags,
-                           struct nameidata *nd, struct path *path)
+                           struct path *path, struct path *root)
 {
         int retval;
-        struct nameidata *saved_nd = set_nameidata(nd);
-
-        retval = path_lookupat(dfd, name, flags | LOOKUP_RCU, nd, path);
+        struct nameidata nd, *saved_nd = set_nameidata(&nd);
+        if (unlikely(root)) {
+                nd.root = *root;
+                flags |= LOOKUP_ROOT;
+        }
+        retval = path_lookupat(dfd, name, flags | LOOKUP_RCU, &nd, path);
         if (unlikely(retval == -ECHILD))
-                retval = path_lookupat(dfd, name, flags, nd, path);
+                retval = path_lookupat(dfd, name, flags, &nd, path);
         if (unlikely(retval == -ESTALE))
                 retval = path_lookupat(dfd, name, flags | LOOKUP_REVAL,
-                                       nd, path); 
+                                       &nd, path);
 
         if (likely(!retval))
                 audit_inode(name, path->dentry, flags & LOOKUP_PARENT);
@@ -2209,11 +2212,10 @@ out:
 
 int kern_path(const char *name, unsigned int flags, struct path *path)
 {
-        struct nameidata nd;
         struct filename *filename = getname_kernel(name);
         if (IS_ERR(filename))
                 return PTR_ERR(filename);
-        return filename_lookup(AT_FDCWD, filename, flags, &nd, path);
+        return filename_lookup(AT_FDCWD, filename, flags, path, NULL);
 }
 EXPORT_SYMBOL(kern_path);
 
@@ -2229,7 +2231,7 @@ int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt,
                     const char *name, unsigned int flags,
                     struct path *path)
 {
-        struct nameidata nd;
+        struct path root = {.mnt = mnt, .dentry = dentry};
         struct filename *filename = getname_kernel(name);
 
         BUG_ON(flags & LOOKUP_PARENT);
@@ -2237,11 +2239,8 @@ int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt,
         if (IS_ERR(filename))
                 return PTR_ERR(filename);
 
-        nd.root.dentry = dentry;
-        nd.root.mnt = mnt;
-        /* the first argument of filename_lookup() is ignored with LOOKUP_ROOT */
-        return filename_lookup(AT_FDCWD, filename,
-                                      flags | LOOKUP_ROOT, &nd, path);
+        /* the first argument of filename_lookup() is ignored with root */
+        return filename_lookup(AT_FDCWD, filename, flags , path, &root);
 }
 EXPORT_SYMBOL(vfs_path_lookup);
 
@@ -2299,14 +2298,13 @@ EXPORT_SYMBOL(lookup_one_len);
 int user_path_at_empty(int dfd, const char __user *name, unsigned flags,
                  struct path *path, int *empty)
 {
-        struct nameidata nd;
         struct filename *tmp = getname_flags(name, flags, empty);
         if (IS_ERR(tmp))
                 return PTR_ERR(tmp);
 
         BUG_ON(flags & LOOKUP_PARENT);
 
-        return filename_lookup(dfd, tmp, flags, &nd, path);
+        return filename_lookup(dfd, tmp, flags, path, NULL);
 }
 
 int user_path_at(int dfd, const char __user *name, unsigned flags,