raid5-cache: correct condition for empty metadata write

shligit · shligit · commit 9a8b27fac5bb · 2016-10-28T22:04:03.000-07:00
As long as we recover one metadata block, we should write the empty metadata
write. The original code could make recovery corrupted if only one meta is
valid.

Reported-by: Zhengyuan Liu &lt;liuzhengyuan@kylinos.cn&gt;
Signed-off-by: Shaohua Li &lt;shli@fb.com&gt;
diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
@@ -1087,7 +1087,7 @@ static int r5l_recovery_log(struct r5l_log *log)
 	 * 1's seq + 10 and let superblock points to meta2. The same recovery will
 	 * not think meta 3 is a valid meta, because its seq doesn't match
 	 */
-	if (ctx.seq > log->last_cp_seq + 1) {
+	if (ctx.seq > log->last_cp_seq) {
 		int ret;
 
 		ret = r5l_log_write_empty_meta_block(log, ctx.pos, ctx.seq + 10);
