On Tue, May 29, 2018 at 10:38:57PM +0200, Kevin Wolf wrote:
> So far we relied on job->ret and strerror() to produce an error message
> for failed jobs. Not surprisingly, this tends to result in completely
> useless messages.
>
> This adds a Job.error field that can contain an error string for a
> failing job, and a parameter to job_completed() that sets the field. As
> a default, if NULL is passed, we continue to use strerror(job->ret).
>
> All existing callers are changed to pass NULL. They can be improved in
> separate patches.
>
> Signed-off-by: Kevin Wolf <kw...@redhat.com>
> ---
> include/qemu/job.h | 7 ++++++-
> block/backup.c | 2 +-
> block/commit.c | 2 +-
> block/mirror.c | 2 +-
> block/stream.c | 2 +-
> job-qmp.c | 9 ++-------
> job.c | 16 ++++++++++++++--
> tests/test-bdrv-drain.c | 2 +-
> tests/test-blockjob-txn.c | 2 +-
> tests/test-blockjob.c | 2 +-
> 10 files changed, 29 insertions(+), 17 deletions(-)
>
> diff --git a/include/qemu/job.h b/include/qemu/job.h
> index 8c8badf75e..1d820530fa 100644
> --- a/include/qemu/job.h
> +++ b/include/qemu/job.h
> @@ -124,6 +124,9 @@ typedef struct Job {
> /** Estimated progress_current value at the completion of the job */
> int64_t progress_total;
>
> + /** Error string for a failed job (NULL if, and only if, job->ret == 0)
> */
> + char *error;
> +
> /** ret code passed to job_completed. */
> int ret;
>
> @@ -466,13 +469,15 @@ void job_transition_to_ready(Job *job);
> /**
> * @job: The job being completed.
> * @ret: The status code.
> + * @error: The error message for a failing job (only with @ret < 0). If @ret
> is
> + * negative, but NULL is given for @error, strerror() is used.
> *
> * Marks @job as completed. If @ret is non-zero, the job transaction it is
> part
> * of is aborted. If @ret is zero, the job moves into the WAITING state. If
> it
> * is the last job to complete in its transaction, all jobs in the
> transaction
> * move from WAITING to PENDING.
> */
> -void job_completed(Job *job, int ret);
> +void job_completed(Job *job, int ret, Error *error);
>
> /** Asynchronously complete the specified @job. */
> void job_complete(Job *job, Error **errp);
> diff --git a/block/backup.c b/block/backup.c
> index 4e228e959b..5661435675 100644
> --- a/block/backup.c
> +++ b/block/backup.c
> @@ -321,7 +321,7 @@ static void backup_complete(Job *job, void *opaque)
> {
> BackupCompleteData *data = opaque;
>
> - job_completed(job, data->ret);
> + job_completed(job, data->ret, NULL);
> g_free(data);
> }
>
> diff --git a/block/commit.c b/block/commit.c
> index 620666161b..e1814d9693 100644
> --- a/block/commit.c
> +++ b/block/commit.c
> @@ -117,7 +117,7 @@ static void commit_complete(Job *job, void *opaque)
> * bdrv_set_backing_hd() to fail. */
> block_job_remove_all_bdrv(bjob);
>
> - job_completed(job, ret);
> + job_completed(job, ret, NULL);
> g_free(data);
>
> /* If bdrv_drop_intermediate() didn't already do that, remove the commit
> diff --git a/block/mirror.c b/block/mirror.c
> index dcb66ec3be..435268bbbf 100644
> --- a/block/mirror.c
> +++ b/block/mirror.c
> @@ -581,7 +581,7 @@ static void mirror_exit(Job *job, void *opaque)
> blk_set_perm(bjob->blk, 0, BLK_PERM_ALL, &error_abort);
> blk_insert_bs(bjob->blk, mirror_top_bs, &error_abort);
>
> - job_completed(job, data->ret);
> + job_completed(job, data->ret, NULL);
>
> g_free(data);
> bdrv_drained_end(src);
> diff --git a/block/stream.c b/block/stream.c
> index a5d6e0cf8a..9264b68a1e 100644
> --- a/block/stream.c
> +++ b/block/stream.c
> @@ -93,7 +93,7 @@ out:
> }
>
> g_free(s->backing_file_str);
> - job_completed(job, data->ret);
> + job_completed(job, data->ret, NULL);
> g_free(data);
> }
>
> diff --git a/job-qmp.c b/job-qmp.c
> index 7f38f63336..410775df61 100644
> --- a/job-qmp.c
> +++ b/job-qmp.c
> @@ -136,14 +136,9 @@ void qmp_job_dismiss(const char *id, Error **errp)
> static JobInfo *job_query_single(Job *job, Error **errp)
> {
> JobInfo *info;
> - const char *errmsg = NULL;
>
> assert(!job_is_internal(job));
>
> - if (job->ret < 0) {
> - errmsg = strerror(-job->ret);
> - }
> -
> info = g_new(JobInfo, 1);
> *info = (JobInfo) {
> .id = g_strdup(job->id),
> @@ -151,8 +146,8 @@ static JobInfo *job_query_single(Job *job, Error **errp)
> .status = job->status,
> .current_progress = job->progress_current,
> .total_progress = job->progress_total,
> - .has_error = !!errmsg,
> - .error = g_strdup(errmsg),
> + .has_error = !!job->error,
> + .error = g_strdup(job->error),
> };
>
> return info;
> diff --git a/job.c b/job.c
> index f026661b0f..84e140238b 100644
> --- a/job.c
> +++ b/job.c
> @@ -369,6 +369,7 @@ void job_unref(Job *job)
>
> QLIST_REMOVE(job, job_list);
>
> + g_free(job->error);
> g_free(job->id);
> g_free(job);
> }
> @@ -660,6 +661,9 @@ static void job_update_rc(Job *job)
> job->ret = -ECANCELED;
> }
> if (job->ret) {
> + if (!job->error) {
> + job->error = g_strdup(strerror(-job->ret));
> + }
> job_state_transition(job, JOB_STATUS_ABORTING);
> }
> }
> @@ -782,6 +786,7 @@ static int job_prepare(Job *job)
> {
> if (job->ret == 0 && job->driver->prepare) {
> job->ret = job->driver->prepare(job);
> + job_update_rc(job);
> }
> return job->ret;
> }
> @@ -855,10 +860,17 @@ static void job_completed_txn_success(Job *job)
> }
> }
>
> -void job_completed(Job *job, int ret)
> +void job_completed(Job *job, int ret, Error *error)
> {
> assert(job && job->txn && !job_is_completed(job));
Is it worth it to add '&& job->ret <=0' to the compound assert above? As
you said, job->ret being positive is most likely a bug (we treat it like an
error return, and abort on it, though). With the patch as-is, we will only
catch that when 'error' is set... although, I guess maybe that is by design,
since currently nothing sets 'error', we avoid any potential false-positive
asserts.
Either way:
Reviewed-by: Jeff Cody <jc...@redhat.com>
> +
> job->ret = ret;
> + if (error) {
> + assert(job->ret < 0);
> + job->error = g_strdup(error_get_pretty(error));
> + error_free(error);
> + }
> +
> job_update_rc(job);
> trace_job_completed(job, ret, job->ret);
> if (job->ret) {
> @@ -876,7 +888,7 @@ void job_cancel(Job *job, bool force)
> }
> job_cancel_async(job, force);
> if (!job_started(job)) {
> - job_completed(job, -ECANCELED);
> + job_completed(job, -ECANCELED, NULL);
> } else if (job->deferred_to_main_loop) {
> job_completed_txn_abort(job);
> } else {
> diff --git a/tests/test-bdrv-drain.c b/tests/test-bdrv-drain.c
> index 2cba63b881..a11c4cfbf2 100644
> --- a/tests/test-bdrv-drain.c
> +++ b/tests/test-bdrv-drain.c
> @@ -498,7 +498,7 @@ typedef struct TestBlockJob {
>
> static void test_job_completed(Job *job, void *opaque)
> {
> - job_completed(job, 0);
> + job_completed(job, 0, NULL);
> }
>
> static void coroutine_fn test_job_start(void *opaque)
> diff --git a/tests/test-blockjob-txn.c b/tests/test-blockjob-txn.c
> index fce836639a..58d9b87fb2 100644
> --- a/tests/test-blockjob-txn.c
> +++ b/tests/test-blockjob-txn.c
> @@ -34,7 +34,7 @@ static void test_block_job_complete(Job *job, void *opaque)
> rc = -ECANCELED;
> }
>
> - job_completed(job, rc);
> + job_completed(job, rc, NULL);
> bdrv_unref(bs);
> }
>
> diff --git a/tests/test-blockjob.c b/tests/test-blockjob.c
> index e408d52351..cb42f06e61 100644
> --- a/tests/test-blockjob.c
> +++ b/tests/test-blockjob.c
> @@ -167,7 +167,7 @@ static void cancel_job_completed(Job *job, void *opaque)
> {
> CancelJob *s = opaque;
> s->completed = true;
> - job_completed(job, 0);
> + job_completed(job, 0, NULL);
> }
>
> static void cancel_job_complete(Job *job, Error **errp)
> --
> 2.13.6
>
