/*
* unionfs_lookup is the only special function which takes a dentry, yet we
* do NOT want to call __unionfs_d_revalidate_chain because by definition,
* we don't have a valid dentry here yet.
*/
static struct dentry *unionfs_lookup(struct inode *dir,
struct dentry *dentry,
/* XXX: pass flags to lower? */
unsigned int flags_unused)
{
struct dentry *ret, *parent;
int err = 0;
unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
/*
* As long as we lock/dget the parent, then can skip validating the
* parent now; we may have to rebuild this dentry on the next
* ->d_revalidate, however.
*/
/* allocate dentry private data. We free it in ->d_release */
err = new_dentry_private_data(dentry, UNIONFS_DMUTEX_CHILD);
if (unlikely(err)) {
ret = ERR_PTR(err);
goto out;
}
ret = unionfs_lookup_full(dentry, parent, INTERPOSE_LOOKUP);
if (!IS_ERR(ret)) {
if (ret)
dentry = ret;
/* lookup_full can return multiple positive dentries */
if (dentry->d_inode && !S_ISDIR(dentry->d_inode->i_mode)) {
BUG_ON(dbstart(dentry) < 0);
unionfs_postcopyup_release(dentry);
}
unionfs_copy_attr_times(dentry->d_inode);
}
unionfs_check_inode(dir);
if (!IS_ERR(ret))
unionfs_check_dentry(dentry);
unionfs_check_dentry(parent);
unionfs_unlock_dentry(dentry); /* locked in new_dentry_private data */
out:
unionfs_unlock_parent(dentry, parent);
unionfs_read_unlock(dentry->d_sb);
return ret;
}
/*
* This is a utility function that fills in a unionfs dentry.
* Caller must lock this dentry with unionfs_lock_dentry.
*
* Returns: 0 (ok), or -ERRNO if an error occurred.
* XXX: get rid of _partial_lookup and make callers call _lookup_full directly
*/
int unionfs_partial_lookup(struct dentry *dentry, struct dentry *parent)
{
struct dentry *tmp;
int err = -ENOSYS;
tmp = unionfs_lookup_full(dentry, parent, INTERPOSE_PARTIAL);
if (!tmp) {
err = 0;
goto out;
}
if (IS_ERR(tmp)) {
err = PTR_ERR(tmp);
goto out;
}
/* XXX: need to change the interface */
BUG_ON(tmp != dentry);
out:
return err;
}
