From 21b172a3ce13c3b499e4265628f7d7c7e1189749 Mon Sep 17 00:00:00 2001
From: WangJian <wangjian161@huawei.com>
Date: Wed, 9 Feb 2022 11:18:21 +0800
Subject: [PATCH] block: enable cache mode of empty cdrom

enable cache mode even if cdrom is empty

Signed-off-by: wangjian161 <wangjian161@huawei.com>
---
 blockdev.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/blockdev.c b/blockdev.c
index 10a73fa423..37e3ee6f26 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -492,6 +492,7 @@ static BlockBackend *blockdev_init(const char *file, QDict *bs_opts,
     QDict *interval_dict = NULL;
     QList *interval_list = NULL;
     const char *id;
+    const char *cache;
     BlockdevDetectZeroesOptions detect_zeroes =
         BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;
     const char *throttling_group = NULL;
@@ -583,6 +584,21 @@ static BlockBackend *blockdev_init(const char *file, QDict *bs_opts,
 
     read_only = qemu_opt_get_bool(opts, BDRV_OPT_READ_ONLY, false);
 
+    if (!file || !*file) {
+        cache = qdict_get_try_str(bs_opts, BDRV_OPT_CACHE_NO_FLUSH);
+        if (cache && !strcmp(cache, "on")) {
+            bdrv_flags |= BDRV_O_NO_FLUSH;
+        }
+
+        cache = qdict_get_try_str(bs_opts, BDRV_OPT_CACHE_DIRECT);
+        if (cache && !strcmp(cache, "on")) {
+            bdrv_flags |= BDRV_O_NOCACHE;
+        }
+
+        qdict_del(bs_opts, BDRV_OPT_CACHE_NO_FLUSH);
+        qdict_del(bs_opts, BDRV_OPT_CACHE_DIRECT);
+    }
+
     /* init */
     if ((!file || !*file) && !qdict_size(bs_opts)) {
         BlockBackendRootState *blk_rs;
-- 
2.27.0