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Re: [Qemu-devel] [PATCH v3] blockjob: Fix hang in block_job_finish_sync
From: |
Fam Zheng |
Subject: |
Re: [Qemu-devel] [PATCH v3] blockjob: Fix hang in block_job_finish_sync |
Date: |
Mon, 1 Feb 2016 10:49:00 +0800 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Fri, 01/29 11:31, Stefan Hajnoczi wrote:
> On Fri, Jan 29, 2016 at 10:19:49AM +0800, Fam Zheng wrote:
> > @@ -402,6 +407,10 @@ typedef void BlockJobDeferToMainLoopFn(BlockJob *job,
> > void *opaque);
> > * AioContext acquired. Block jobs must call bdrv_unref(), bdrv_close(),
> > and
> > * anything that uses bdrv_drain_all() in the main loop.
> > *
> > + * The job->deferred_to_main_loop flag will be set. Caller must clear it
> > once
> > + * the deferred work is done and the block job coroutine continues, unless
> > it's
> > + * completing immediately.
> > + *
>
> It's not necessary to expose job->deferred_to_main_loop to the user.
> Just clear it:
>
> static void block_job_defer_to_main_loop_bh(void *opaque)
> {
> BlockJobDeferToMainLoopData *data = opaque;
> AioContext *aio_context;
>
> qemu_bh_delete(data->bh);
>
> /* Prevent race with block_job_defer_to_main_loop() */
> aio_context_acquire(data->aio_context);
>
> /* Fetch BDS AioContext again, in case it has changed */
> aio_context = bdrv_get_aio_context(data->job->bs);
> aio_context_acquire(aio_context);
>
> data->fn(data->job, data->opaque);
> job->deferred_to_main_loop = false; /* <----- HERE */
Maybe move one line above in case data->fn() does another
block_job_defer_to_main_loop()?
Fam
>
> aio_context_release(aio_context);
>
> aio_context_release(data->aio_context);
>
> g_free(data);
> }