NAME
check_submounts_and_drop - prune dcache, check for submounts and drop
SYNOPSIS
int check_submounts_and_drop(struct dentry * dentry);
ARGUMENTS
dentry
dentry to prune and drop
DESCRIPTION
All done as a single atomic operation relative to has_unlinked_ancestor. Returns 0 if successfully unhashed parent. If there were submounts then return -EBUSY.