On Tue, May 20, 2014 at 02:04:29PM +0800, Fam Zheng wrote:
> It makes no sense to check for "any" blocker on bs, we are here only
> because of the mechanical conversion from in_use to op_blockers. Remove
> it now, and let the callers check specific operation types. Backup and
> mirror already have it, add checker to stream and commit.
>
> Signed-off-by: Fam Zheng <f...@redhat.com>
> Reviewed-by: Benoit Canet <ben...@irqsave.net>
> Reviewed-by: Jeff Cody <jc...@redhat.com>
> ---
> blockdev.c | 8 ++++++++
> blockjob.c | 2 +-
> 2 files changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/blockdev.c b/blockdev.c
> index 5d950fa..21fc55b 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -1850,6 +1850,10 @@ void qmp_block_stream(const char *device, bool
> has_base,
> return;
> }
>
> + if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_STREAM, errp)) {
> + return;
> + }
> +
> if (base) {
> base_bs = bdrv_find_backing_image(bs, base);
> if (base_bs == NULL) {
> @@ -1894,6 +1898,10 @@ void qmp_block_commit(const char *device,
> return;
> }
>
> + if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT, errp)) {
> + return;
> + }
> +
Is the blocker intended to operate at the device level, i.e. to mark a
whole chain as 'blocked' for one or more operations? Or, is it
intended to block at the singular BDS level (the commit message in
patch 2 implies this meaning)?
More to the point: if a BDS is marked as blocked, does that also imply
all of the images in its backing chain are also considered blocked?
Conversely, if a BDS is *not* marked as blocked, does that mean all of
its backing chain is also unblocked?
If the answer to the two questions above is 'yes', then the
bdrv_op_block/unblock functions should probably operate recursively
down the chain to the bottom-most backing file.
If the answer is 'no', then for some operations like stream and commit
(and probably others), don't we also need to worry about the blocker
state of a lot more images in the chain?
> /* default top_bs is the active layer */
> top_bs = bs;
>
> diff --git a/blockjob.c b/blockjob.c
> index 60e72f5..7d84ca1 100644
> --- a/blockjob.c
> +++ b/blockjob.c
> @@ -41,7 +41,7 @@ void *block_job_create(const BlockJobDriver *driver,
> BlockDriverState *bs,
> {
> BlockJob *job;
>
> - if (bs->job || !bdrv_op_blocker_is_empty(bs)) {
> + if (bs->job) {
> error_set(errp, QERR_DEVICE_IN_USE, bdrv_get_device_name(bs));
> return NULL;
> }
> --
> 1.9.2
>
