[Qemu-devel] [PATCH] block: fix cache flushing in bdrv_commit

[Christoph Hellwig <hch@lst.de>]

On Thu, Jan 14, 2010 at 11:21:15AM +0100, Kevin Wolf wrote:
> Anthony, you seem to have missed the v2 patch that considered my review
> comments. Can you please apply the diff between v1 and v2 on top?

Here is the differences in patch form:

---
From: Christoph Hellwig <hch@lst.de>
Subject: block: fix cache flushing in bdrv_commit

As pointed out by Kevin Wolf the previous patch returned early if we
there is a bdrv_make_empty method and it missed a cache flush for the
frontend device after the bdev_make_empty call.  This patch fixes it
up.

Signed-off-by: Christoph Hellwig <hch@lst.de>


Index: qemu/block.c
===================================================================
--- qemu.orig/block.c	2010-01-17 12:27:03.589006970 +0100
+++ qemu/block.c	2010-01-17 12:27:55.718008519 +0100
@@ -589,6 +589,7 @@ int bdrv_commit(BlockDriverState *bs)
     BlockDriver *drv = bs->drv;
     int64_t i, total_sectors;
     int n, j;
+    int ret = 0;
     unsigned char sector[512];
 
     if (!drv)
@@ -620,8 +621,10 @@ int bdrv_commit(BlockDriverState *bs)
         }
     }
 
-    if (drv->bdrv_make_empty)
-	return drv->bdrv_make_empty(bs);
+    if (drv->bdrv_make_empty) {
+        ret = drv->bdrv_make_empty(bs);
+        bdrv_flush(bs);
+    }
 
     /*
      * Make sure all data we wrote to the backing device is actually
@@ -629,7 +632,7 @@ int bdrv_commit(BlockDriverState *bs)
      */
     if (bs->backing_hd)
         bdrv_flush(bs->backing_hd);
-    return 0;
+    return ret;
 }
 
 /*