On Fri, 09/11 20:52, Max Reitz wrote:
> On 07.09.2015 09:34, Fam Zheng wrote:
> > Sometimes block jobs must execute as a transaction group. Finishing
> > jobs wait until all other jobs are ready to complete successfully.
> > Failure or cancellation of one job cancels the other jobs in the group.
> >
> > Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
> > [Rewrite the implementation which is now contained in block_job_completed.
> > --Fam]
> > Signed-off-by: Fam Zheng <f...@redhat.com>
> > ---
> > blockjob.c | 134
> > ++++++++++++++++++++++++++++++++++++++++++++++-
> > include/block/block.h | 1 +
> > include/block/blockjob.h | 38 ++++++++++++++
> > 3 files changed, 171 insertions(+), 2 deletions(-)
> >
> > diff --git a/blockjob.c b/blockjob.c
> > index 36c18e0..1b4eb20 100644
> > --- a/blockjob.c
> > +++ b/blockjob.c
> > @@ -36,6 +36,19 @@
> > #include "qemu/timer.h"
> > #include "qapi-event.h"
> >
> > +/* Transactional group of block jobs */
> > +struct BlockJobTxn {
> > +
> > + /* Is this txn being cancelled? */
> > + bool aborting;
> > +
> > + /* List of jobs */
> > + QLIST_HEAD(, BlockJob) jobs;
> > +
> > + /* Reference count */
> > + int refcnt;
> > +};
> > +
> > void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs,
> > int64_t speed, BlockCompletionFunc *cb,
> > void *opaque, Error **errp)
> > @@ -90,6 +103,85 @@ void block_job_unref(BlockJob *job)
> > }
> > }
> >
> > +static void block_job_completed_single(BlockJob *job)
> > +{
> > + if (!job->ret) {
> > + if (job->driver->commit) {
> > + job->driver->commit(job);
> > + }
> > + } else {
> > + if (job->driver->abort) {
> > + job->driver->abort(job);
> > + }
> > + }
> > + job->cb(job->opaque, job->ret);
> > + block_job_unref(job);
> > +}
> > +
> > +static void block_job_completed_txn_abort(BlockJob *job)
> > +{
> > + AioContext *ctx;
> > + BlockJobTxn *txn = job->txn;
> > + BlockJob *other_job, *next;
> > +
> > + if (txn->aborting) {
> > + /*
> > + * We are cancelled by another job, which will handle everything.
> > + */
>
> After having reviewed patch 11, I think we need to call
> block_job_txn_unref(txn) here.
>
> > + return;
> > + }
> > + txn->aborting = true;
> > + /* We are the first failed job. Cancel other jobs. */
> > + QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
> > + ctx = bdrv_get_aio_context(other_job->bs);
> > + aio_context_acquire(ctx);
> > + }
> > + QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
> > + if (other_job == job || other_job->completed) {
> > + /* Other jobs are "effectively" cancelled by us, set the
> > status for
> > + * them; this job, however, may or may not be cancelled,
> > depending
> > + * on the caller, so leave it. */
> > + if (other_job != job) {
> > + other_job->cancelled = true;
> > + }
> > + continue;
> > + }
> > + block_job_cancel_sync(other_job);
> > + assert(other_job->completed);
> > + }
> > + QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) {
> > + ctx = bdrv_get_aio_context(other_job->bs);
> > + block_job_completed_single(other_job);
> > + aio_context_release(ctx);
> > + }
> > + block_job_txn_unref(txn);
> > +}
> > +
> > +static void block_job_completed_txn_success(BlockJob *job)
> > +{
> > + AioContext *ctx;
> > + BlockJobTxn *txn = job->txn;
> > + BlockJob *other_job, *next;
> > + /*
> > + * Successful completion, see if there are other running jobs in this
> > + * txn.
> > + **/
> > + QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
> > + if (!other_job->completed) {
>
> Same here.
Yes. Will add at ...
> > + return;
> > + }
> > + }
> > + /* We are the last completed job, commit the transaction. */
> > + QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) {
> > + ctx = bdrv_get_aio_context(other_job->bs);
> > + aio_context_acquire(ctx);
> > + assert(other_job->ret == 0);
> > + block_job_completed_single(other_job);
> > + aio_context_release(ctx);
> > + }
> > + block_job_txn_unref(txn);
> > +}
> > +
> > void block_job_completed(BlockJob *job, int ret)
> > {
> > BlockDriverState *bs = job->bs;
> > @@ -98,8 +190,13 @@ void block_job_completed(BlockJob *job, int ret)
> > assert(!job->completed);
> > job->completed = true;
> > job->ret = ret;
> > - job->cb(job->opaque, ret);
> > - block_job_unref(job);
> > + if (!job->txn) {
> > + block_job_completed_single(job);
> > + } else if (ret < 0 || block_job_is_cancelled(job)) {
> > + block_job_completed_txn_abort(job);
> > + } else {
> > + block_job_completed_txn_success(job);
> > + }
Here in an "if (job->txn)" branch.
Fam
> > }
