From 5669b44de5b3b607a3a4749e0c8c5ddfd723e76b Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Fri, 11 Apr 2014 21:36:45 +0200 Subject: [PATCH] block: Remove BDRV_O_COPY_ON_READ for bs->file Copy on Read makes sense on the format level where backing files are implemented, but it's not required on the protocol level. While it shouldn't actively break anything to have COR enabled on both layers, needless serialisation and allocation checks may impact performance. Signed-off-by: Kevin Wolf Reviewed-by: Max Reitz --- block.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/block.c b/block.c index c6d5ab9cb8..9f88bcc088 100644 --- a/block.c +++ b/block.c @@ -793,7 +793,7 @@ static int bdrv_inherited_flags(int flags) } /* Clear flags that only apply to the top layer */ - flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING); + flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_COPY_ON_READ); return flags; }