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[PATCH v8 4/7] copy-on-read: pass base file name to COR driver
From: |
Andrey Shinkevich |
Subject: |
[PATCH v8 4/7] copy-on-read: pass base file name to COR driver |
Date: |
Fri, 28 Aug 2020 19:52:56 +0300 |
To limit the guest's COR operations by the base node in the backing
chain during stream job, pass the base file name to the copy-on-read
driver. The rest of the functionality will be implemented in the patch
that follows.
Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
---
block/copy-on-read.c | 41 ++++++++++++++++++++++++++++++++++++++++-
block/copy-on-read.h | 1 +
2 files changed, 41 insertions(+), 1 deletion(-)
diff --git a/block/copy-on-read.c b/block/copy-on-read.c
index 0ede7aa..1f858bb 100644
--- a/block/copy-on-read.c
+++ b/block/copy-on-read.c
@@ -24,19 +24,45 @@
#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_bs;
} BDRVStateCOR;
+/*
+ * Non-zero pointers are the caller's responsibility.
+ */
+static BlockDriverState *get_base_by_name(BlockDriverState *bs,
+ const char *base_name, Error **errp)
+{
+ BlockDriverState *base_bs = NULL;
+ AioContext *aio_context;
+
+ base_bs = bdrv_find_backing_image(bs, base_name);
+ if (base_bs == NULL) {
+ error_setg(errp, QERR_BASE_NOT_FOUND, base_name);
+ return NULL;
+ }
+
+ aio_context = bdrv_get_aio_context(bs);
+ aio_context_acquire(aio_context);
+ assert(bdrv_get_aio_context(base_bs) == aio_context);
+ aio_context_release(aio_context);
+
+ return base_bs;
+}
static int cor_open(BlockDriverState *bs, QDict *options, int flags,
Error **errp)
{
+ BlockDriverState *base_bs = NULL;
BDRVStateCOR *state = bs->opaque;
+ const char *base_name = qdict_get_try_str(options, "base");
bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY,
@@ -52,7 +78,15 @@ static int cor_open(BlockDriverState *bs, QDict *options,
int flags,
((BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK) &
bs->file->bs->supported_zero_flags);
+ if (base_name) {
+ qdict_del(options, "base");
+ base_bs = get_base_by_name(bs, base_name, errp);
+ if (!base_bs) {
+ return -EINVAL;
+ }
+ }
state->active = true;
+ state->base_bs = base_bs;
/*
* We don't need to call bdrv_child_refresh_perms() now as the permissions
@@ -190,6 +224,7 @@ static void bdrv_copy_on_read_init(void)
static BlockDriverState *create_filter_node(BlockDriverState *bs,
+ const char *base_name,
const char *filter_node_name,
Error **errp)
{
@@ -197,6 +232,9 @@ static BlockDriverState
*create_filter_node(BlockDriverState *bs,
qdict_put_str(opts, "driver", "copy-on-read");
qdict_put_str(opts, "file", bdrv_get_node_name(bs));
+ if (base_name) {
+ qdict_put_str(opts, "base", base_name);
+ }
if (filter_node_name) {
qdict_put_str(opts, "node-name", filter_node_name);
}
@@ -206,13 +244,14 @@ static BlockDriverState
*create_filter_node(BlockDriverState *bs,
BlockDriverState *bdrv_cor_filter_append(BlockDriverState *bs,
+ const char *base_name,
const char *filter_node_name,
Error **errp)
{
BlockDriverState *cor_filter_bs;
Error *local_err = NULL;
- cor_filter_bs = create_filter_node(bs, filter_node_name, errp);
+ cor_filter_bs = create_filter_node(bs, base_name, filter_node_name, errp);
if (cor_filter_bs == NULL) {
error_prepend(errp, "Could not create filter node: ");
return NULL;
diff --git a/block/copy-on-read.h b/block/copy-on-read.h
index 1686e4e..6a7c8bb 100644
--- a/block/copy-on-read.h
+++ b/block/copy-on-read.h
@@ -28,6 +28,7 @@
#include "block/block_int.h"
BlockDriverState *bdrv_cor_filter_append(BlockDriverState *bs,
+ const char *base_name,
const char *filter_node_name,
Error **errp);
void bdrv_cor_filter_drop(BlockDriverState *cor_filter_bs);
--
1.8.3.1
- [PATCH v8 0/7] Apply COR-filter to the block-stream permanently, Andrey Shinkevich, 2020/08/28
- [PATCH v8 1/7] copy-on-read: Support preadv/pwritev_part functions, Andrey Shinkevich, 2020/08/28
- [PATCH v8 2/7] copy-on-read: add filter append/drop functions, Andrey Shinkevich, 2020/08/28
- [PATCH v8 3/7] qapi: add filter-node-name to block-stream, Andrey Shinkevich, 2020/08/28
- [PATCH v8 4/7] copy-on-read: pass base file name to COR driver,
Andrey Shinkevich <=
- [PATCH v8 5/7] copy-on-read: limit guest writes to base in COR driver, Andrey Shinkevich, 2020/08/28
- [PATCH v8 6/7] block-stream: freeze link to base node during stream job, Andrey Shinkevich, 2020/08/28
- [PATCH v8 7/7] block: apply COR-filter to block-stream jobs, Andrey Shinkevich, 2020/08/28