db/db_impl: restrict WALRecoveryMode when using recycled log files

kPointInTimeRecovery is indistinguishable from
kTolerateCorruptedTailRecords in recycle mode since we define
the "end" of the log as the first corrupt record we encounter.

kAbsoluteConsistency doesn't make sense because even a clean
shutdown leaves old junk at the end of the log file.

Signed-off-by: Sage Weil <sage@redhat.com>

db/db_impl.cc

@@ -169,6 +169,17 @@ DBOptions SanitizeOptions(const std::string& dbname, const DBOptions& src) {
     result.recycle_log_file_num = false;
   }
 
+  if (result.recycle_log_file_num &&
+      (result.wal_recovery_mode == WALRecoveryMode::kPointInTimeRecovery ||
+       result.wal_recovery_mode == WALRecoveryMode::kAbsoluteConsistency)) {
+    // kPointInTimeRecovery is indistinguishable from
+    // kTolerateCorruptedTailRecords in recycle mode since we define
+    // the "end" of the log as the first corrupt record we encounter.
+    // kAbsoluteConsistency doesn't make sense because even a clean
+    // shutdown leaves old junk at the end of the log file.
+    result.wal_recovery_mode = WALRecoveryMode::kTolerateCorruptedTailRecords;
+  }
+
   if (result.wal_dir.empty()) {
     // Use dbname as default
     result.wal_dir = dbname;