From 4c241cf5d6ca06c682e033cf8b327b63b1f4b784 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Mon, 8 May 2017 16:13:06 +0200 Subject: blockjob: introduce block_job_cancel_async, check iostatus invariants The new functions helps respecting the invariant that the coroutine is entered with false user_resume, zero pause count and no error recorded in the iostatus. Resetting the iostatus is now common to all of block_job_cancel_async, block_job_user_resume and block_job_iostatus_reset, albeit with slight differences: - block_job_cancel_async resets the iostatus, and resumes the job if there was an error, but the coroutine is not restarted immediately. For example the caller may continue with a call to block_job_finish_sync. - block_job_user_resume resets the iostatus. It wants to resume the job unconditionally, even if there was no error. - block_job_iostatus_reset doesn't resume the job at all. Maybe that's a bug but it should be fixed separately. block_job_iostatus_reset does the least common denominator, so add some checking but otherwise leave it as the entry point for resetting the iostatus. Reviewed-by: Stefan Hajnoczi Signed-off-by: Paolo Bonzini Message-id: 20170508141310.8674-8-pbonzini@redhat.com Signed-off-by: Jeff Cody --- blockjob.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) (limited to 'blockjob.c') diff --git a/blockjob.c b/blockjob.c index cd1f4c0712..eae8fe7cbf 100644 --- a/blockjob.c +++ b/blockjob.c @@ -304,6 +304,19 @@ static void block_job_completed_single(BlockJob *job) block_job_unref(job); } +static void block_job_cancel_async(BlockJob *job) +{ + if (job->iostatus != BLOCK_DEVICE_IO_STATUS_OK) { + block_job_iostatus_reset(job); + } + if (job->user_paused) { + /* Do not call block_job_enter here, the caller will handle it. */ + job->user_paused = false; + job->pause_count--; + } + job->cancelled = true; +} + static void block_job_completed_txn_abort(BlockJob *job) { AioContext *ctx; @@ -328,7 +341,7 @@ static void block_job_completed_txn_abort(BlockJob *job) * 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; + block_job_cancel_async(other_job); } continue; } @@ -411,8 +424,8 @@ bool block_job_user_paused(BlockJob *job) void block_job_user_resume(BlockJob *job) { if (job && job->user_paused && job->pause_count > 0) { - job->user_paused = false; block_job_iostatus_reset(job); + job->user_paused = false; block_job_resume(job); } } @@ -420,8 +433,7 @@ void block_job_user_resume(BlockJob *job) void block_job_cancel(BlockJob *job) { if (block_job_started(job)) { - job->cancelled = true; - block_job_iostatus_reset(job); + block_job_cancel_async(job); block_job_enter(job); } else { block_job_completed(job, -ECANCELED); @@ -765,6 +777,10 @@ void block_job_yield(BlockJob *job) void block_job_iostatus_reset(BlockJob *job) { + if (job->iostatus == BLOCK_DEVICE_IO_STATUS_OK) { + return; + } + assert(job->user_paused && job->pause_count > 0); job->iostatus = BLOCK_DEVICE_IO_STATUS_OK; } -- cgit v1.2.1