[PATCH vfs-2.6 2/6] vfs: add d_ancestor()

This adds d_ancestor() instead of d_isparent(), then use it.

If new_dentry == old_dentry, is_subdir() returns 1, looks strange.
"new_dentry == old_dentry" is not subdir obviously. But I'm not
checking callers for now, so this keeps current behavior.

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>

1 files changed, 10 insertions, 12 deletions

diff --git a/fs/namei.c b/fs/namei.c
index 068a9e50c8c0..b7cd65224d60 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1454,20 +1454,18 @@ struct dentry *lock_rename(struct dentry *p1, struct dentry *p2)
 
         mutex_lock(&p1->d_inode->i_sb->s_vfs_rename_mutex);
 
-        for (p = p1; !IS_ROOT(p); p = p->d_parent) {
-                if (p->d_parent == p2) {
-                        mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_PARENT);
-                        mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_CHILD);
-                        return p;
-                }
+        p = d_ancestor(p2, p1);
+        if (p) {
+                mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_PARENT);
+                mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_CHILD);
+                return p;
         }
 
-        for (p = p2; !IS_ROOT(p); p = p->d_parent) {
-                if (p->d_parent == p1) {
-                        mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT);
-                        mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_CHILD);
-                        return p;
-                }
+        p = d_ancestor(p1, p2);
+        if (p) {
+                mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT);
+                mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_CHILD);
+                return p;
         }
 
         mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT);