PXB-3374 : Space ID is missing encryption information

With lock-ddl=REDUCED, the following sequence can happen (Not possible
with lock-ddl=ON)

    1. first an IBD with all zero(invalid) encryption is found
    2. so this is added to invalid encryption ids
    3. the same IBD is found again (because of concurrent DDL, they are both found with different names)
    4. this time IBD has proper encryption,  so fil_space_t is created
    5. encryption info from redo is parsed. fil_tablespace_redo_encryption()
    6. because the fil_space_t exists, encryption key is not added to the recovery encryption keys map
    7. later at the end of the backup, we check if we have found a valid encryption key for the invalid encryption space_ids.
    8. we haven’t (remember at step 6, we skipped it)
    9. backup is aborted

Fix:
----
Store keys in recv_sys->keys map even if there exists a tablespace

storage/innobase/fil/fil0fil.cc

@@ -11227,7 +11227,7 @@ const byte *fil_tablespace_redo_encryption(const byte *ptr, const byte *end,
         xb::error() << KEYRING_NOT_LOADED;
         exit(EXIT_FAILURE);
       }
-      return (ptr + len);
+      return (ptr);
     }
   } else {
     ulint master_key_id = mach_read_from_4(ptr + Encryption::MAGIC_SIZE);
@@ -11240,13 +11240,6 @@ const byte *fil_tablespace_redo_encryption(const byte *ptr, const byte *end,
 
   ut_ad(len == Encryption::INFO_SIZE);
 
-  if (space != nullptr) {
-    Encryption::set_or_generate(Encryption::AES, key, iv,
-                                space->m_encryption_metadata);
-    fsp_flags_set_encryption(space->flags);
-    return ptr;
-  }
-
   /* Space is not loaded yet. Remember this key in recv_sys and use it later
   to pupulate space encryption info once it is loaded. */
   DBUG_EXECUTE_IF("dont_update_key_found_during_REDO_scan", return ptr;);
@@ -11256,27 +11249,37 @@ const byte *fil_tablespace_redo_encryption(const byte *ptr, const byte *end,
         ut::new_withkey<recv_sys_t::Encryption_Keys>(UT_NEW_THIS_FILE_PSI_KEY);
   }
 
+  bool key_exists = false;
   /* Search if key entry already exists for this tablespace, update it. */
   for (auto &recv_key : *recv_sys->keys) {
     if (recv_key.space_id == space_id) {
       memcpy(recv_key.iv, iv, Encryption::KEY_LEN);
       memcpy(recv_key.ptr, key, Encryption::KEY_LEN);
       recv_key.lsn = lsn;
-      return ptr;
+      key_exists = true;
+      break;
     }
   }
 
-  /* No existing entry found, create new one and insert it. */
-  recv_sys_t::Encryption_Key new_key;
-  new_key.iv = static_cast<byte *>(
-      ut::malloc_withkey(UT_NEW_THIS_FILE_PSI_KEY, Encryption::KEY_LEN));
-  memcpy(new_key.iv, iv, Encryption::KEY_LEN);
-  new_key.ptr = static_cast<byte *>(
-      ut::malloc_withkey(UT_NEW_THIS_FILE_PSI_KEY, Encryption::KEY_LEN));
-  memcpy(new_key.ptr, key, Encryption::KEY_LEN);
-  new_key.space_id = space_id;
-  new_key.lsn = lsn;
-  recv_sys->keys->push_back(new_key);
+  if (!key_exists) {
+    /* No existing entry found, create new one and insert it. */
+    recv_sys_t::Encryption_Key new_key;
+    new_key.iv = static_cast<byte *>(
+        ut::malloc_withkey(UT_NEW_THIS_FILE_PSI_KEY, Encryption::KEY_LEN));
+    memcpy(new_key.iv, iv, Encryption::KEY_LEN);
+    new_key.ptr = static_cast<byte *>(
+        ut::malloc_withkey(UT_NEW_THIS_FILE_PSI_KEY, Encryption::KEY_LEN));
+    memcpy(new_key.ptr, key, Encryption::KEY_LEN);
+    new_key.space_id = space_id;
+    new_key.lsn = lsn;
+    recv_sys->keys->push_back(new_key);
+  }
+
+  if (space != nullptr) {
+    Encryption::set_or_generate(Encryption::AES, key, iv,
+                                space->m_encryption_metadata);
+    fsp_flags_set_encryption(space->flags);
+  }
 
   return ptr;
 }