Man page 9 : drop_nlink

drop_nlink - directly drop an inodeAqs link count

void drop_nlink(struct inode *  inode );

inode
    inode

This is a low-level filesystem helper to replace any direct filesystem manipulation of i_nlink. In cases where we are attempting to track writes to the filesystem, a decrement to zero means an imminent write when the file is truncated and actually unlinked on the filesystem.