quota: Pass information that quota is stored in system file to userspace

Quota tools need to know whether quota is stored in a system file or in
classical aquota.{user|group} files. So pass this information as a flag
in GETINFO quotactl.

Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/include/linux/quota.h b/include/linux/quota.h
index cb78556..c09fa04 100644
--- a/include/linux/quota.h
+++ b/include/linux/quota.h
@@ -230,7 +230,11 @@
 struct super_block;
 
 #define DQF_MASK 0xffff		/* Mask for format specific flags */
-#define DQF_INFO_DIRTY_B 16
+#define DQF_GETINFO_MASK 0x1ffff	/* Mask for flags passed to userspace */
+#define DQF_SETINFO_MASK 0xffff		/* Mask for flags modifiable from userspace */
+#define DQF_SYS_FILE_B		16
+#define DQF_SYS_FILE (1 << DQF_SYS_FILE_B)	/* Quota file stored as system file */
+#define DQF_INFO_DIRTY_B	31
 #define DQF_INFO_DIRTY (1 << DQF_INFO_DIRTY_B)	/* Is info dirty? */
 
 extern void mark_info_dirty(struct super_block *sb, int type);