[XFS] Add a mechanism for XFS to use the generic quota sync method.
This is now used to issue a delayed allocation flush before reporting
quota, which allows the used space quota report to match reality.

Signed-off-by: Nathan Scott <nathans@sgi.com>
diff --git a/fs/quota.c b/fs/quota.c
index f5d1cff..1df7832 100644
--- a/fs/quota.c
+++ b/fs/quota.c
@@ -118,6 +118,10 @@
 			if (!sb->s_qcop->get_xquota)
 				return -ENOSYS;
 			break;
+		case Q_XQUOTASYNC:
+			if (!sb->s_qcop->quota_sync)
+				return -ENOSYS;
+			break;
 		default:
 			return -EINVAL;
 	}
@@ -128,7 +132,7 @@
 		     (type == XQM_GRPQUOTA && !in_egroup_p(id))) &&
 		     !capable(CAP_SYS_ADMIN))
 			return -EPERM;
-	} else if (cmd != Q_XGETQSTAT) {
+	} else if (cmd != Q_XGETQSTAT && cmd != Q_XQUOTASYNC) {
 		if (!capable(CAP_SYS_ADMIN))
 			return -EPERM;
 	}
@@ -322,6 +326,8 @@
 				return -EFAULT;
 			return 0;
 		}
+		case Q_XQUOTASYNC:
+			return sb->s_qcop->quota_sync(sb, type);
 		/* We never reach here unless validity check is broken */
 		default:
 			BUG();