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Re: [Qemu-devel] [PATCH v3 4/9] block/commit: utilize job_exit shim
From: |
Jeff Cody |
Subject: |
Re: [Qemu-devel] [PATCH v3 4/9] block/commit: utilize job_exit shim |
Date: |
Fri, 31 Aug 2018 09:58:25 -0400 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
On Wed, Aug 29, 2018 at 09:57:29PM -0400, John Snow wrote:
> Change the manual deferment to commit_complete into the implicit
> callback to job_exit, renaming commit_complete to commit_exit.
>
> This conversion does change the timing of when job_completed is
> called to after the bdrv_replace_node and bdrv_unref calls, which
> could have implications for bjob->blk which will now be put down
> after this cleanup.
>
> Kevin highlights that we did not take any permissions for that backend
> at job creation time, so it is safe to reorder these operations.
>
> Signed-off-by: John Snow <address@hidden>
> Reviewed-by: Max Reitz <address@hidden>
> ---
> block/commit.c | 22 +++++-----------------
> 1 file changed, 5 insertions(+), 17 deletions(-)
>
> diff --git a/block/commit.c b/block/commit.c
> index 4a17bb73ec..da69165de3 100644
> --- a/block/commit.c
> +++ b/block/commit.c
> @@ -68,19 +68,13 @@ static int coroutine_fn commit_populate(BlockBackend *bs,
> BlockBackend *base,
> return 0;
> }
>
> -typedef struct {
> - int ret;
> -} CommitCompleteData;
> -
> -static void commit_complete(Job *job, void *opaque)
> +static void commit_exit(Job *job)
> {
> CommitBlockJob *s = container_of(job, CommitBlockJob, common.job);
> BlockJob *bjob = &s->common;
> - CommitCompleteData *data = opaque;
> BlockDriverState *top = blk_bs(s->top);
> BlockDriverState *base = blk_bs(s->base);
> BlockDriverState *commit_top_bs = s->commit_top_bs;
> - int ret = data->ret;
> bool remove_commit_top_bs = false;
>
> /* Make sure commit_top_bs and top stay around until bdrv_replace_node()
> */
> @@ -91,10 +85,10 @@ static void commit_complete(Job *job, void *opaque)
> * the normal backing chain can be restored. */
> blk_unref(s->base);
>
> - if (!job_is_cancelled(job) && ret == 0) {
> + if (!job_is_cancelled(job) && job->ret == 0) {
> /* success */
> - ret = bdrv_drop_intermediate(s->commit_top_bs, base,
> - s->backing_file_str);
> + job->ret = bdrv_drop_intermediate(s->commit_top_bs, base,
> + s->backing_file_str);
> } else {
> /* XXX Can (or should) we somehow keep 'consistent read' blocked even
> * after the failed/cancelled commit job is gone? If we already wrote
> @@ -117,9 +111,6 @@ static void commit_complete(Job *job, void *opaque)
> * bdrv_set_backing_hd() to fail. */
> block_job_remove_all_bdrv(bjob);
>
> - job_completed(job, ret);
> - g_free(data);
> -
Not having to allocate, track, and free this cumbersome return value for
each of these job specific completions now is pretty nice.
Reviewed-by: Jeff Cody <address@hidden>
> /* If bdrv_drop_intermediate() didn't already do that, remove the commit
> * filter driver from the backing chain. Do this as the final step so
> that
> * the 'consistent read' permission can be granted. */
> @@ -137,7 +128,6 @@ static void commit_complete(Job *job, void *opaque)
> static int coroutine_fn commit_run(Job *job, Error **errp)
> {
> CommitBlockJob *s = container_of(job, CommitBlockJob, common.job);
> - CommitCompleteData *data;
> int64_t offset;
> uint64_t delay_ns = 0;
> int ret = 0;
> @@ -210,9 +200,6 @@ static int coroutine_fn commit_run(Job *job, Error **errp)
> out:
> qemu_vfree(buf);
>
> - data = g_malloc(sizeof(*data));
> - data->ret = ret;
> - job_defer_to_main_loop(&s->common.job, commit_complete, data);
> return ret;
> }
>
> @@ -224,6 +211,7 @@ static const BlockJobDriver commit_job_driver = {
> .user_resume = block_job_user_resume,
> .drain = block_job_drain,
> .run = commit_run,
> + .exit = commit_exit,
> },
> };
>
> --
> 2.14.4
>
- Re: [Qemu-devel] [PATCH v3 2/9] jobs: canonize Error object, (continued)
- [Qemu-devel] [PATCH v3 5/9] block/mirror: utilize job_exit shim, John Snow, 2018/08/29
- [Qemu-devel] [PATCH v3 7/9] block/backup: make function variables consistently named, John Snow, 2018/08/29
- [Qemu-devel] [PATCH v3 8/9] jobs: remove ret argument to job_completed; privatize it, John Snow, 2018/08/29
- [Qemu-devel] [PATCH v3 9/9] jobs: remove job_defer_to_main_loop, John Snow, 2018/08/29
- [Qemu-devel] [PATCH v3 4/9] block/commit: utilize job_exit shim, John Snow, 2018/08/29
- Re: [Qemu-devel] [PATCH v3 4/9] block/commit: utilize job_exit shim,
Jeff Cody <=
- [Qemu-devel] [PATCH v3 6/9] jobs: utilize job_exit shim, John Snow, 2018/08/29
- [Qemu-devel] [PATCH v3 3/9] jobs: add exit shim, John Snow, 2018/08/29
- Re: [Qemu-devel] [PATCH v3 0/9] jobs: Job Exit Refactoring Pt 1, Max Reitz, 2018/08/31