Re: [Qemu-block] [PATCH 08/18] block/mirror: Use source as a BdrvChild

[Max Reitz]

On 2017-10-10 11:27, Kevin Wolf wrote:
> Am 13.09.2017 um 20:19 hat Max Reitz geschrieben:
>> With this, the mirror_top_bs is no longer just a technically required
>> node in the BDS graph but actually represents the block job operation.
>>
>> Signed-off-by: Max Reitz 
>> ---
>>  block/mirror.c | 18 ++
>>  1 file changed, 10 insertions(+), 8 deletions(-)
>>
>> diff --git a/block/mirror.c b/block/mirror.c
>> index 2ece38094d..9df4157511 100644
>> --- a/block/mirror.c
>> +++ b/block/mirror.c
>> @@ -43,8 +43,8 @@ typedef struct MirrorBlockJob {
>>  RateLimit limit;
>>  BlockBackend *target;
>>  BlockDriverState *mirror_top_bs;
>> -BlockDriverState *source;
>>  BlockDriverState *base;
>> +BdrvChild *source;
> 
> Is it actually useful to store source seperately when we already have
> mirror_top_bs->backing?

I'll take a look whether it is, and if it isn't, I'll probably add that
as a separate patch (to keep this one as simple as it is).

I imagine it is not, right.

Max



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Re: [Qemu-block] [PATCH 08/18] block/mirror: Use source as a BdrvChild

[Kevin Wolf]

Am 13.09.2017 um 20:19 hat Max Reitz geschrieben:
> With this, the mirror_top_bs is no longer just a technically required
> node in the BDS graph but actually represents the block job operation.
> 
> Signed-off-by: Max Reitz 
> ---
>  block/mirror.c | 18 ++
>  1 file changed, 10 insertions(+), 8 deletions(-)
> 
> diff --git a/block/mirror.c b/block/mirror.c
> index 2ece38094d..9df4157511 100644
> --- a/block/mirror.c
> +++ b/block/mirror.c
> @@ -43,8 +43,8 @@ typedef struct MirrorBlockJob {
>  RateLimit limit;
>  BlockBackend *target;
>  BlockDriverState *mirror_top_bs;
> -BlockDriverState *source;
>  BlockDriverState *base;
> +BdrvChild *source;

Is it actually useful to store source seperately when we already have
mirror_top_bs->backing?

Kevin

[Qemu-block] [PATCH 08/18] block/mirror: Use source as a BdrvChild

[Max Reitz]

With this, the mirror_top_bs is no longer just a technically required
node in the BDS graph but actually represents the block job operation.

Signed-off-by: Max Reitz 
---
 block/mirror.c | 18 ++
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/block/mirror.c b/block/mirror.c
index 2ece38094d..9df4157511 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -43,8 +43,8 @@ typedef struct MirrorBlockJob {
 RateLimit limit;
 BlockBackend *target;
 BlockDriverState *mirror_top_bs;
-BlockDriverState *source;
 BlockDriverState *base;
+BdrvChild *source;
 
 /* The name of the graph node to replace */
 char *replaces;
@@ -294,7 +294,6 @@ static void coroutine_fn mirror_co_read(void *opaque)
 {
 MirrorOp *op = opaque;
 MirrorBlockJob *s = op->s;
-BlockBackend *source = s->common.blk;
 int nb_chunks;
 uint64_t ret;
 uint64_t max_bytes;
@@ -344,7 +343,7 @@ static void coroutine_fn mirror_co_read(void *opaque)
 s->bytes_in_flight += op->bytes;
 trace_mirror_one_iteration(s, op->offset, op->bytes);
 
-ret = blk_co_preadv(source, op->offset, op->bytes, &op->qiov, 0);
+ret = bdrv_co_preadv(s->source, op->offset, op->bytes, &op->qiov, 0);
 mirror_read_complete(op, ret);
 }
 
@@ -416,7 +415,7 @@ static unsigned mirror_perform(MirrorBlockJob *s, int64_t 
offset,
 
 static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
 {
-BlockDriverState *source = s->source;
+BlockDriverState *source = s->source->bs;
 MirrorOp *pseudo_op;
 int64_t offset;
 uint64_t delay_ns = 0, ret = 0;
@@ -597,7 +596,7 @@ static void mirror_exit(BlockJob *job, void *opaque)
 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
 MirrorExitData *data = opaque;
 AioContext *replace_aio_context = NULL;
-BlockDriverState *src = s->source;
+BlockDriverState *src = s->source->bs;
 BlockDriverState *target_bs = blk_bs(s->target);
 BlockDriverState *mirror_top_bs = s->mirror_top_bs;
 Error *local_err = NULL;
@@ -712,7 +711,7 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s)
 {
 int64_t sector_num, end;
 BlockDriverState *base = s->base;
-BlockDriverState *bs = s->source;
+BlockDriverState *bs = s->source->bs;
 BlockDriverState *target_bs = blk_bs(s->target);
 int ret, n;
 int64_t count;
@@ -802,7 +801,7 @@ static void coroutine_fn mirror_run(void *opaque)
 {
 MirrorBlockJob *s = opaque;
 MirrorExitData *data;
-BlockDriverState *bs = s->source;
+BlockDriverState *bs = s->source->bs;
 BlockDriverState *target_bs = blk_bs(s->target);
 bool need_drain = true;
 int64_t length;
@@ -1284,7 +1283,7 @@ static void mirror_start_job(const char *job_id, 
BlockDriverState *bs,
 /* The block job now has a reference to this node */
 bdrv_unref(mirror_top_bs);
 
-s->source = bs;
+s->source = mirror_top_bs->backing;
 s->mirror_top_bs = mirror_top_bs;
 
 /* No resize for the target either; while the mirror is still running, a
@@ -1330,6 +1329,9 @@ static void mirror_start_job(const char *job_id, 
BlockDriverState *bs,
 s->should_complete = true;
 }
 
+s->source = mirror_top_bs->backing;
+s->mirror_top_bs = mirror_top_bs;
+
 s->dirty_bitmap = bdrv_create_dirty_bitmap(bs, granularity, NULL, errp);
 if (!s->dirty_bitmap) {
 goto fail;
-- 
2.13.5