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

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(+) 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"); bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds, BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY, @@ -52,7 +57,16 @@ 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_overlay_node) { + qdict_del(options, "base"); + base_overlay = bdrv_lookup_bs(NULL, base_overlay_node, errp); + if (!base_overlay) { + error_setg(errp, QERR_BASE_NOT_FOUND, base_overlay_node); + return -EINVAL; + } + } state->active = true; + state->base_overlay = base_overlay; /* * We don't need to call bdrv_child_refresh_perms() now as the permissions -- 1.8.3.1