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[Qemu-devel] [PATCH 4/5] block: Make backing files always writeback
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [PATCH 4/5] block: Make backing files always writeback |
Date: |
Mon, 14 Mar 2016 16:44:51 +0100 |
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 <address@hidden>
---
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 698e2c7..666fe61 100644
--- a/block.c
+++ b/block.c
@@ -762,8 +762,9 @@ 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
- [Qemu-devel] [PATCH 0/5] block: API changes for 2.6, Kevin Wolf, 2016/03/14
- [Qemu-devel] [PATCH 2/5] block: Remove dirty bitmaps from bdrv_move_feature_fields(), Kevin Wolf, 2016/03/14
- [Qemu-devel] [PATCH 1/5] block: Remove copy-on-read from bdrv_move_feature_fields(), Kevin Wolf, 2016/03/14
- [Qemu-devel] [PATCH 4/5] block: Make backing files always writeback,
Kevin Wolf <=
- [Qemu-devel] [PATCH 3/5] block: Remove cache.writeback from blockdev-add, Kevin Wolf, 2016/03/14
- [Qemu-devel] [PATCH 5/5] block: Reject writethrough mode except at the root, Kevin Wolf, 2016/03/14
- Re: [Qemu-devel] [PATCH 0/5] block: API changes for 2.6, Kevin Wolf, 2016/03/18