14.10.2020 14:57, Max Reitz wrote:
On 14.10.20 13:09, Max Reitz wrote:
On 12.10.20 19:43, Andrey Shinkevich wrote:
We are going to use the COR-filter for a block-stream job.
To limit COR operations by the base node in the backing chain during
stream job, pass the name of overlay base node to the copy-on-read
driver as base node itself may change due to possible concurrent jobs.
The rest of the functionality will be implemented in the patch that
follows.
Signed-off-by: Andrey Shinkevich <andrey.shinkevich@xxxxxxxxxxxxx>
---
block/copy-on-read.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
Is there a reason why you didn’t add this option to QAPI (as part of a
yet-to-be-created BlockdevOptionsCor)? Because I’d really like it there.
diff --git a/block/copy-on-read.c b/block/copy-on-read.c
index bcccf0f..c578b1b 100644
--- a/block/copy-on-read.c
+++ b/block/copy-on-read.c
@@ -24,19 +24,24 @@
#include "block/block_int.h"
#include "qemu/module.h"
#include "qapi/error.h"
+#include "qapi/qmp/qerror.h"
#include "qapi/qmp/qdict.h"
#include "block/copy-on-read.h"
typedef struct BDRVStateCOR {
bool active;
+ BlockDriverState *base_overlay;
} BDRVStateCOR;
static int cor_open(BlockDriverState *bs, QDict *options, int flags,
Error **errp)
{
+ BlockDriverState *base_overlay = NULL;
BDRVStateCOR *state = bs->opaque;
+ /* We need the base overlay node rather than the base itself */
+ const char *base_overlay_node = qdict_get_try_str(options, "base");
Shouldn’t it be called base-overlay or above-base then?
While reviewing patch 5, I realized this sould indeed be base-overlay
(i.e. the next allocation-bearing layer above the base, not just a
filter on top of base), but that should be noted somewhere, of course.
Best would be the QAPI documentation for this option. O:)
What about naming it just "bottom" or "bottom-node"? If we don't have base, it's strange to have something "relative to base". And we can document, that "bottom" must be a non-filter node in a backing chain of "top".
--
Best regards,
Vladimir
