Simpler mdb_env_write_meta()

libraries/liblmdb/mdb.c

@@ -3694,15 +3694,12 @@ mdb_env_write_meta(MDB_txn *txn)
 		if (!(flags & (MDB_NOMETASYNC|MDB_NOSYNC))) {
 			unsigned meta_size = env->me_psize;
 			rc = (env->me_flags & MDB_MAPASYNC) ? MS_ASYNC : MS_SYNC;
-			ptr = env->me_map;
-			if (toggle) {
+			ptr = (char *)mp - PAGEHDRSZ;
 #ifndef _WIN32	/* POSIX msync() requires ptr = start of OS page */
-				if (meta_size < env->me_os_psize)
-					meta_size += meta_size;
-				else
+			r2 = (ptr - env->me_map) & (env->me_os_psize - 1);
+			ptr -= r2;
+			meta_size += r2;
 #endif
-					ptr += meta_size;
-			}
 			if (MDB_MSYNC(ptr, meta_size, rc)) {
 				rc = ErrCode();
 				goto fail;
@@ -3710,8 +3707,8 @@ mdb_env_write_meta(MDB_txn *txn)
 		}
 		goto done;
 	}
-	metab.mm_txnid = env->me_metas[toggle]->mm_txnid;
-	metab.mm_last_pg = env->me_metas[toggle]->mm_last_pg;
+	metab.mm_txnid = mp->mm_txnid;
+	metab.mm_last_pg = mp->mm_last_pg;
 
 	meta.mm_mapsize = mapsize;
 	meta.mm_dbs[FREE_DBI] = txn->mt_dbs[FREE_DBI];
@@ -3722,9 +3719,7 @@ mdb_env_write_meta(MDB_txn *txn)
 	off = offsetof(MDB_meta, mm_mapsize);
 	ptr = (char *)&meta + off;
 	len = sizeof(MDB_meta) - off;
-	if (toggle)
-		off += env->me_psize;
-	off += PAGEHDRSZ;
+	off += (char *)mp - env->me_map;
 
 	/* Write to the SYNC fd */
 	mfd = (flags & (MDB_NOSYNC|MDB_NOMETASYNC)) ? env->me_fd : env->me_mfd;