> > Yup, it's already not too bad. I haven't looked into it in much
> > detail, but I'd like to reduce it even a bit more. In particular, the
> > backup_info field in the BlockDriverState feels wrong to me. In the
> > long term the generic block layer shouldn't know at all what a backup
> > is, and baking it into BDS couples it very tightly.
>
> My plan was to have something like bs->job->job_type->{before,after}_write.
>
> int coroutine_fn (*before_write)(BlockDriverState *bs,
> int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
> void **cookie);
> int coroutine_fn (*after_write)(BlockDriverState *bs,
> int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
> void *cookie);
I don't think that job is the right place. Instead I would put a list
of filters into BDS:
typedef struct BlockFilter {
void *opaque;
int cluster_size;
int coroutine_fn (before_read)(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
BdrvRequestFlags flags, void **cookie);
int coroutine_fn (after_read)(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
BdrvRequestFlags flags, void *cookie);
int coroutine_fn (*before_write)(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
void **cookie);
int coroutine_fn (*after_write)(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
void *cookie);
} BlockFilter;
struct BlockDriverState {
...
QLIST_HEAD(, BlockFilters) filters;
};
Would that work for you?
