quota: Make VFS quotas use new interface for getting quota info

Create new internal interface for getting information about quota which
contains everything needed for both VFS quotas and XFS quotas. Make VFS
use this and hook it up to Q_GETINFO.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

fs/quota/quota.c

@@ -118,13 +118,30 @@ static int quota_getfmt(struct super_block *sb, int type, void __user *addr)
 
 static int quota_getinfo(struct super_block *sb, int type, void __user *addr)
 {
-	struct if_dqinfo info;
+	struct qc_state state;
+	struct qc_type_state *tstate;
+	struct if_dqinfo uinfo;
 	int ret;
 
-	if (!sb->s_qcop->get_info)
+	/* This checks whether qc_state has enough entries... */
+	BUILD_BUG_ON(MAXQUOTAS > XQM_MAXQUOTAS);
+	if (!sb->s_qcop->get_state)
 		return -ENOSYS;
-	ret = sb->s_qcop->get_info(sb, type, &info);
-	if (!ret && copy_to_user(addr, &info, sizeof(info)))
+	ret = sb->s_qcop->get_state(sb, &state);
+	if (ret)
+		return ret;
+	tstate = state.s_state + type;
+	if (!(tstate->flags & QCI_ACCT_ENABLED))
+		return -ESRCH;
+	memset(&uinfo, 0, sizeof(uinfo));
+	uinfo.dqi_bgrace = tstate->spc_timelimit;
+	uinfo.dqi_igrace = tstate->ino_timelimit;
+	if (tstate->flags & QCI_SYSFILE)
+		uinfo.dqi_flags |= DQF_SYS_FILE;
+	if (tstate->flags & QCI_ROOT_SQUASH)
+		uinfo.dqi_flags |= DQF_ROOT_SQUASH;
+	uinfo.dqi_valid = IIF_ALL;
+	if (!ret && copy_to_user(addr, &uinfo, sizeof(uinfo)))
 		return -EFAULT;
 	return ret;
 }