Re: [PATCH v11 04/13] copy-on-read: pass overlay base node name to COR driver

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(a)virtuozzo.com&gt; >> --- >> 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:)