1 void
  2 d_move(struct dentry *dentry,
  3        struct dentry *target)
  4 {
  5   spin_lock(&dcache_lock);
  6   write_seqlock(&rename_lock);
  7   if (target < dentry) {
  8     spin_lock(&target->d_lock);
  9     spin_lock(&dentry->d_lock);
 10   } else {
 11     spin_lock(&dentry->d_lock);
 12     spin_lock(&target->d_lock);
 13   }
 14   if (dentry->d_vfs_flags & DCACHE_UNHASHED)
 15     goto already_unhashed;
 16   if (dentry->d_bucket != target->d_bucket) {
 17     hlist_del_rcu(&dentry->d_hash);
 18 already_unhashed:
 19     dentry->d_bucket = target->d_bucket;
 20     hlist_add_head_rcu(&dentry->d_hash,
 21                        target->d_bucket);
 22     dentry->d_vfs_flags &= ~DCACHE_UNHASHED;
 23   }
 24   __d_drop(target);
 25   list_del(&dentry->d_child);
 26   list_del(&target->d_child);
 27   switch_names(dentry, target);
 28   smp_wmb();
 29   do_switch(dentry->d_name.len,
 30             target->d_name.len);
 31   do_switch(dentry->d_name.hash,
 32             target->d_name.hash);
 33   if (IS_ROOT(dentry)) {
 34     dentry->d_parent = target->d_parent;
 35     target->d_parent = target;
 36     INIT_LIST_HEAD(&target->d_child);
 37   } else {
 38     do_switch(dentry->d_parent,
 39               target->d_parent);
 40     list_add(&target->d_child,
 41        &target->d_parent->d_subdirs);
 42   }
 43   list_add(&dentry->d_child,
 44      &dentry->d_parent->d_subdirs);
 45   dentry->d_move_count++;
 46   spin_unlock(&target->d_lock);
 47   spin_unlock(&dentry->d_lock);
 48   write_sequnlock(&rename_lock);
 49   spin_unlock(&dcache_lock);
 50 }