Beispiel #1
0
/*
 * test if the @h_dentry sets opaque or not.
 */
int au_diropq_test(struct dentry *h_dentry, struct au_branch *br)
{
	int err;
	struct inode *h_dir;

	h_dir = h_dentry->d_inode;
	err = au_wh_test(h_dentry, &diropq_name, br,
			 au_test_h_perm_sio(h_dir, MAY_EXEC));
	return err;
}
/*
 * returns positive/negative dentry, NULL or an error.
 * NULL means whiteout-ed or not-found.
 */
static struct dentry*
au_do_lookup(struct dentry *h_parent, struct dentry *dentry,
	     aufs_bindex_t bindex, struct qstr *wh_name,
	     struct au_do_lookup_args *args)
{
	struct dentry *h_dentry;
	struct inode *h_inode, *inode;
	struct au_branch *br;
	int wh_found, opq;
	unsigned char wh_able;
	const unsigned char allow_neg = !!au_ftest_lkup(args->flags, ALLOW_NEG);

	wh_found = 0;
	br = au_sbr(dentry->d_sb, bindex);
	wh_able = !!au_br_whable(br->br_perm);
	if (wh_able)
		wh_found = au_wh_test(h_parent, wh_name, br, /*try_sio*/0);
	h_dentry = ERR_PTR(wh_found);
	if (!wh_found)
		goto real_lookup;
	if (unlikely(wh_found < 0))
		goto out;

	/* We found a whiteout */
	/* au_set_dbend(dentry, bindex); */
	au_set_dbwh(dentry, bindex);
	if (!allow_neg)
		return NULL; /* success */

real_lookup:
	h_dentry = au_lkup_one(&dentry->d_name, h_parent, br, args->nd);
	if (IS_ERR(h_dentry))
		goto out;

	h_inode = h_dentry->d_inode;
	if (!h_inode) {
		if (!allow_neg)
			goto out_neg;
	} else if (wh_found
		   || (args->type && args->type != (h_inode->i_mode & S_IFMT)))
		goto out_neg;

	if (au_dbend(dentry) <= bindex)
		au_set_dbend(dentry, bindex);
	if (au_dbstart(dentry) < 0 || bindex < au_dbstart(dentry))
		au_set_dbstart(dentry, bindex);
	au_set_h_dptr(dentry, bindex, h_dentry);

	inode = dentry->d_inode;
	if (!h_inode || !S_ISDIR(h_inode->i_mode) || !wh_able
	    || (inode && !S_ISDIR(inode->i_mode)))
		goto out; /* success */

	mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
	opq = au_diropq_test(h_dentry, br);
	mutex_unlock(&h_inode->i_mutex);
	if (opq > 0)
		au_set_dbdiropq(dentry, bindex);
	else if (unlikely(opq < 0)) {
		au_set_h_dptr(dentry, bindex, NULL);
		h_dentry = ERR_PTR(opq);
	}
	goto out;

out_neg:
	dput(h_dentry);
	h_dentry = NULL;
out:
	return h_dentry;
}