void ntfs_put_inode (struct inode * vi);
The VFS calls ntfs_put_inode every time the inode reference count (i_count) is about to be decremented (but before the decrement itself.
If the inode vi is a directory with a single reference, we need to put the attribute inode for the directory index bitmap, if it is present, otherwise the directory inode would remain pinned for ever (or rather until umount time.