First of all, we're generally not writing to backing files, but when we
do, it's in the context of block jobs which know very well when to flush
the image.
Signed-off-by: Kevin Wolf <kw...@redhat.com>
Reviewed-by: Eric Blake <ebl...@redhat.com>
---
block.c | 5 +++--
tests/qemu-iotests/142.out | 10 +++++-----
2 files changed, 8 insertions(+), 7 deletions(-)
diff --git a/block.c b/block.c
index 6592b35..5da7bb2 100644
--- a/block.c
+++ b/block.c
@@ -737,8 +737,9 @@ static void bdrv_backing_options(int *child_flags, QDict
*child_options,
{
int flags = parent_flags;
- /* The cache mode is inherited unmodified for backing files */
- qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_WB);
+ /* The cache mode is inherited unmodified for backing files; except WCE,
+ * which is only applied on the top level (BlockBackend) */
+ qdict_set_default_str(child_options, BDRV_OPT_CACHE_WB, "on");
qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT);
qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH);
diff --git a/tests/qemu-iotests/142.out b/tests/qemu-iotests/142.out
index b555d5a..abe94c3 100644
--- a/tests/qemu-iotests/142.out
+++ b/tests/qemu-iotests/142.out
@@ -62,7 +62,7 @@ cache.direct=on on backing-file
cache.writeback=off on none0
Cache mode: writethrough
Cache mode: writeback
- Cache mode: writethrough
+ Cache mode: writeback
Cache mode: writeback
cache.writeback=off on file
@@ -143,7 +143,7 @@ cache.writeback=off on none0
Cache mode: writethrough
Cache mode: writethrough
Cache mode: writeback
- Cache mode: writethrough
+ Cache mode: writeback
Cache mode: writeback
cache.writeback=off on file
@@ -302,7 +302,7 @@ cache.direct=on on backing-file
cache.writeback=off on none0
Cache mode: writethrough, direct
Cache mode: writeback, direct
- Cache mode: writethrough, direct
+ Cache mode: writeback, direct
Cache mode: writeback, direct
cache.writeback=off on file
@@ -383,7 +383,7 @@ cache.writeback=off on none0
Cache mode: writeback, direct
Cache mode: writethrough
Cache mode: writeback
- Cache mode: writethrough
+ Cache mode: writeback
Cache mode: writeback
cache.writeback=off on file
@@ -718,7 +718,7 @@ cache.direct=on on backing-file
cache.writeback=off on none0
Cache mode: writethrough
Cache mode: writeback
- Cache mode: writethrough, direct
+ Cache mode: writeback, direct
Cache mode: writeback, direct
cache.writeback=off on file
--
1.8.3.1
