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[Qemu-devel] [PATCH 3/6] block: Remove BDRV_O_COPY_ON_READ for bs->file
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [PATCH 3/6] block: Remove BDRV_O_COPY_ON_READ for bs->file |
Date: |
Fri, 25 Apr 2014 19:51:09 +0200 |
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 <address@hidden>
---
block.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/block.c b/block.c
index 25c5663..7070cdb 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;
}
--
1.8.3.1
- [Qemu-devel] [PATCH 0/6] block: bdrv_open() fixes and cleanups, Kevin Wolf, 2014/04/25
- [Qemu-devel] [PATCH 1/6] block: Create bdrv_inherited_flags(), Kevin Wolf, 2014/04/25
- [Qemu-devel] [PATCH 4/6] block: Unlink temporary files in raw-posix/win32, Kevin Wolf, 2014/04/25
- [Qemu-devel] [PATCH 5/6] Revert "block: another bdrv_append fix", Kevin Wolf, 2014/04/25
- [Qemu-devel] [PATCH 2/6] block: Create bdrv_backing_flags(), Kevin Wolf, 2014/04/25
- [Qemu-devel] [PATCH 3/6] block: Remove BDRV_O_COPY_ON_READ for bs->file,
Kevin Wolf <=
- [Qemu-devel] [PATCH 6/6] block: Fix open_flags in bdrv_reopen(), Kevin Wolf, 2014/04/25