From: Adam Kupczyk <akupczyk@ibm.com>
Date: Thu, 6 Jun 2024 18:10:45 +0000 (+0000)
Subject: include/denc: Add protection against bumping up compat
X-Git-Tag: v19.1.1~100^2~5
X-Git-Url: http://git.apps.os.sepia.ceph.com/?a=commitdiff_plain;h=ea0ef1cbce0bee226c166333e901f29160a95e14;p=ceph.git

include/denc: Add protection against bumping up compat

Added protection against bumping up compat until U_____ release (SQUID+2)

Signed-off-by: Adam Kupczyk <akupczyk@ibm.com>
(cherry picked from commit c94c8baf012b66ba2fe13abbeb2f27c16c717df4)
---

diff --git a/src/include/denc.h b/src/include/denc.h
index 623e4639cb57f..1ebc395e70ee4 100644
--- a/src/include/denc.h
+++ b/src/include/denc.h
@@ -51,6 +51,7 @@
 
 #include "common/convenience.h"
 #include "common/error_code.h"
+#include "ceph_ver.h"
 
 template<typename T, typename=void>
 struct denc_traits {
@@ -1845,11 +1846,26 @@ inline std::enable_if_t<traits::supported && !traits::featured> decode_nohead(
 // Helpers for versioning the encoding.  These correspond to the
 // {ENCODE,DECODE}_{START,FINISH} macros.
 
+// DENC_START interface suggests it is checking compatibility,
+// but the feature was unimplemented until SQUID.
+// Due to -2 compatibility rule we cannot bump up compat until U____ release.
+
 #define DENC_START(v, compat, p)					\
   __u8 struct_v = v;							\
   __u8 struct_compat = compat;						\
   char *_denc_pchar;							\
   uint32_t _denc_u32;							\
+  static_assert(CEPH_RELEASE >= 21 || compat == 1);			\
+  _denc_start(p, &struct_v, &struct_compat, &_denc_pchar, &_denc_u32);	\
+  do {
+
+// For the only type that is with compat 2, osd_reqid_t, and unittest.
+#define DENC_START_COMPAT_2(v, compat, p)				\
+  __u8 struct_v = v;							\
+  __u8 struct_compat = compat;						\
+  char *_denc_pchar;							\
+  uint32_t _denc_u32;							\
+  static_assert(CEPH_RELEASE >= 21 || compat == 2);			\
   _denc_start(p, &struct_v, &struct_compat, &_denc_pchar, &_denc_u32);	\
   do {
 
diff --git a/src/osd/osd_types.h b/src/osd/osd_types.h
index 4a80101c26977..2427fc9ab10f0 100644
--- a/src/osd/osd_types.h
+++ b/src/osd/osd_types.h
@@ -164,7 +164,7 @@ struct osd_reqid_t {
   {}
 
   DENC(osd_reqid_t, v, p) {
-    DENC_START(2, 2, p);
+    DENC_START_COMPAT_2(2, 2, p);
     denc(v.name, p);
     denc(v.tid, p);
     denc(v.inc, p);
diff --git a/src/test/test_denc.cc b/src/test/test_denc.cc
index 46dfe67e9eeef..02dd1454ef8cc 100644
--- a/src/test/test_denc.cc
+++ b/src/test/test_denc.cc
@@ -375,7 +375,7 @@ struct foo2_only2_t {
   uint32_t c = 55;
 
   DENC(foo2_only2_t, v, p) {
-    DENC_START(2, 2, p);
+    DENC_START_COMPAT_2(2, 2, p);
     ::denc(v.a, p);
     ::denc(v.b, p);
     ::denc(v.c, p);