From afebe4a531c1a03a5da3033ffd8984208fdc520c Mon Sep 17 00:00:00 2001
From: Fan Yong <fan.yong@intel.com>
Date: Tue, 16 Aug 2016 16:18:49 -0400
Subject: [PATCH] staging: lustre: reorder LOV_MAGIC_* definition
Since all the LOV_MAGIC_* definitions have the same
postfix values break that value out into its own
definition. With this we can check whether the magic's
postfix match the LOV_MAGIC_MAGIC or not: if yes,
then it is quite possible that the clients has
encountered an newer LOV magic. This extra information
can let us handle those cases more gracefully.
Signed-off-by: Fan Yong <fan.yong@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-4941
Reviewed-on: http://review.whamcloud.com/10045
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
.../lustre/lustre/include/lustre/lustre_idl.h | 20 ++++++++++++++-----
1 file changed, 15 insertions(+), 5 deletions(-)
diff --git a/drivers/staging/lustre/lustre/include/lustre/lustre_idl.h b/drivers/staging/lustre/lustre/include/lustre/lustre_idl.h
index d3a9db921a06c..3444addc3f6b1 100644
--- a/drivers/staging/lustre/lustre/include/lustre/lustre_idl.h
+++ b/drivers/staging/lustre/lustre/include/lustre/lustre_idl.h
@@ -1478,11 +1478,21 @@ enum obdo_flags {
OBD_FL_LOCAL_MASK = 0xF0000000,
};
-#define LOV_MAGIC_V1 0x0BD10BD0
-#define LOV_MAGIC LOV_MAGIC_V1
-#define LOV_MAGIC_JOIN_V1 0x0BD20BD0
-#define LOV_MAGIC_V3 0x0BD30BD0
-#define LOV_MAGIC_MIGRATE 0x0BD40BD0
+/*
+ * All LOV EA magics should have the same postfix, if some new version
+ * Lustre instroduces new LOV EA magic, then when down-grade to an old
+ * Lustre, even though the old version system does not recognizes such
+ * new magic, it still can distinguish the corrupted cases by checking
+ * the magic's postfix.
+ */
+#define LOV_MAGIC_MAGIC 0x0BD0
+#define LOV_MAGIC_MASK 0xFFFF
+
+#define LOV_MAGIC_V1 (0x0BD10000 | LOV_MAGIC_MAGIC)
+#define LOV_MAGIC_JOIN_V1 (0x0BD20000 | LOV_MAGIC_MAGIC)
+#define LOV_MAGIC_V3 (0x0BD30000 | LOV_MAGIC_MAGIC)
+#define LOV_MAGIC_MIGRATE (0x0BD40000 | LOV_MAGIC_MAGIC)
+#define LOV_MAGIC LOV_MAGIC_V1
/*
* magic for fully defined striping
--
2.30.2