Am 22.11.2013 um 06:24 hat Fam Zheng geschrieben:
> BlockDriverState.op_blockers is an array of list with BLOCK_OP_TYPE_MAX
s/list/lists/
> elements. Each list is a list of blockers of an operation type
> (BlockOpType), that marks this BDS is currently blocked for certain type
s/is/as/
s/for/for a/
> of operation with reason errors stored in the list. The rule of usage
> is:
>
> * BDS user who wants to take an operation should check if there's any
> blocker of the type with bdrv_op_is_blocked().
>
> * BDS user who wants to block certain types of operation, should call
> bdrv_op_block (or bdrv_op_block_all to block all types of operations,
> which is similar to bdrv_set_in_use of now).
>
> * A blocker is only referenced by op_blockers, so the lifecycle is
> managed by caller, and shouldn't be lost until unblock, so typically
> a caller does these:
>
> - Allocate a blocker with error_setg or similar, call bdrv_op_block()
> to block some operations.
> - Hold the blocker, do his job.
> - Unblock operations that it blocked, with the same reason pointer
> passed to bdrv_op_unblock().
> - Release the blocker with error_free().
>
> Signed-off-by: Fam Zheng <f...@redhat.com>
> ---
> block.c | 55
> +++++++++++++++++++++++++++++++++++++++++++++++
> include/block/block.h | 6 ++++++
> include/block/block_int.h | 5 +++++
> 3 files changed, 66 insertions(+)
>
> diff --git a/block.c b/block.c
> index 382ea71..2b18a43 100644
> --- a/block.c
> +++ b/block.c
> @@ -4425,6 +4425,61 @@ void bdrv_unref(BlockDriverState *bs)
> }
> }
>
> +struct BdrvOpBlocker {
> + Error *reason;
> + QLIST_ENTRY(BdrvOpBlocker) list;
> +};
> +
> +bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp)
> +{
> + BdrvOpBlocker *blocker;
> + assert(op >=0 && op < BLOCK_OP_TYPE_MAX);
Missing space after >= (same in all other functions)
The logic looks fine.
Kevin
