block: Add bdrv_parse_cache_mode()

It's like bdrv_parse_cache_flags(), except that writethrough mode isn't
included in the flags, but returned as a separate bool.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/block.c b/block.c
index af3584389d..14d2ebc35a 100644
--- a/block.c
+++ b/block.c
@@ -667,6 +667,23 @@ int bdrv_parse_cache_flags(const char *mode, int *flags)
     return 0;
 }
 
+int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough)
+{
+    int ret = bdrv_parse_cache_flags(mode, flags);
+    if (ret < 0) {
+        return ret;
+    }
+
+    if (*flags & BDRV_O_CACHE_WB) {
+        *flags &= ~BDRV_O_CACHE_WB;
+        *writethrough = false;
+    } else {
+        *writethrough = true;
+    }
+
+    return 0;
+}
+
 /*
  * Returns the options and flags that a temporary snapshot should get, based on
  * the originally requested flags (the originally requested image will have