From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34595) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XZNIM-0002mB-Mg for qemu-devel@nongnu.org; Wed, 01 Oct 2014 13:02:38 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XZNIF-0001hI-M2 for qemu-devel@nongnu.org; Wed, 01 Oct 2014 13:02:30 -0400 Received: from mx1.redhat.com ([209.132.183.28]:18706) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XZNIF-0001hE-FU for qemu-devel@nongnu.org; Wed, 01 Oct 2014 13:02:23 -0400 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s91H2MEq000953 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL) for ; Wed, 1 Oct 2014 13:02:23 -0400 From: Stefan Hajnoczi Date: Wed, 1 Oct 2014 18:01:56 +0100 Message-Id: <1412182919-9550-9-git-send-email-stefanha@redhat.com> In-Reply-To: <1412182919-9550-1-git-send-email-stefanha@redhat.com> References: <1412182919-9550-1-git-send-email-stefanha@redhat.com> Subject: [Qemu-devel] [PATCH 08/11] block: let stream blockjob run in BDS AioContext List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Kevin Wolf , Paolo Bonzini , Fam Zheng , Stefan Hajnoczi , Max Reitz The stream block job must run in the BlockDriverState AioContext so that it works with dataplane. The basics of acquiring the AioContext are easy in blockdev.c. The tricky part is the completion code which drops part of the backing file chain. This must be done in the main loop where bdrv_unref() and bdrv_close() are safe to call. Use block_job_defer_to_main_loop() to achieve that. Signed-off-by: Stefan Hajnoczi --- block/stream.c | 50 ++++++++++++++++++++++++++++++++++++-------------- blockdev.c | 16 ++++++++++++---- 2 files changed, 48 insertions(+), 18 deletions(-) diff --git a/block/stream.c b/block/stream.c index cdea3e8..21bce12 100644 --- a/block/stream.c +++ b/block/stream.c @@ -79,9 +79,39 @@ static void close_unused_images(BlockDriverState *top, BlockDriverState *base, bdrv_refresh_limits(top, NULL); } +typedef struct { + int ret; + bool reached_end; +} StreamCompleteData; + +static void stream_complete(BlockJob *job, void *opaque) +{ + StreamBlockJob *s = container_of(job, StreamBlockJob, common); + StreamCompleteData *data = opaque; + BlockDriverState *base = s->base; + + if (!block_job_is_cancelled(&s->common) && data->reached_end && + data->ret == 0) { + const char *base_id = NULL, *base_fmt = NULL; + if (base) { + base_id = s->backing_file_str; + if (base->drv) { + base_fmt = base->drv->format_name; + } + } + data->ret = bdrv_change_backing_file(job->bs, base_id, base_fmt); + close_unused_images(job->bs, base, base_id); + } + + g_free(s->backing_file_str); + block_job_completed(&s->common, data->ret); + g_free(data); +} + static void coroutine_fn stream_run(void *opaque) { StreamBlockJob *s = opaque; + StreamCompleteData *data; BlockDriverState *bs = s->common.bs; BlockDriverState *base = s->base; int64_t sector_num, end; @@ -183,21 +213,13 @@ wait: /* Do not remove the backing file if an error was there but ignored. */ ret = error; - if (!block_job_is_cancelled(&s->common) && sector_num == end && ret == 0) { - const char *base_id = NULL, *base_fmt = NULL; - if (base) { - base_id = s->backing_file_str; - if (base->drv) { - base_fmt = base->drv->format_name; - } - } - ret = bdrv_change_backing_file(bs, base_id, base_fmt); - close_unused_images(bs, base, base_id); - } - qemu_vfree(buf); - g_free(s->backing_file_str); - block_job_completed(&s->common, ret); + + /* Modify backing chain and close BDSes in main loop */ + data = g_malloc(sizeof(*data)); + data->ret = ret; + data->reached_end = sector_num == end; + block_job_defer_to_main_loop(&s->common, stream_complete, data); } static void stream_set_speed(BlockJob *job, int64_t speed, Error **errp) diff --git a/blockdev.c b/blockdev.c index 44f0cc7..5473cd0 100644 --- a/blockdev.c +++ b/blockdev.c @@ -1923,6 +1923,7 @@ void qmp_block_stream(const char *device, { BlockDriverState *bs; BlockDriverState *base_bs = NULL; + AioContext *aio_context; Error *local_err = NULL; const char *base_name = NULL; @@ -1936,16 +1937,20 @@ void qmp_block_stream(const char *device, return; } + aio_context = bdrv_get_aio_context(bs); + aio_context_acquire(aio_context); + if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_STREAM, errp)) { - return; + goto out; } if (has_base) { base_bs = bdrv_find_backing_image(bs, base); if (base_bs == NULL) { error_set(errp, QERR_BASE_NOT_FOUND, base); - return; + goto out; } + assert(bdrv_get_aio_context(base_bs) == aio_context); base_name = base; } @@ -1954,7 +1959,7 @@ void qmp_block_stream(const char *device, if (base_bs == NULL && has_backing_file) { error_setg(errp, "backing file specified, but streaming the " "entire chain"); - return; + goto out; } /* backing_file string overrides base bs filename */ @@ -1964,10 +1969,13 @@ void qmp_block_stream(const char *device, on_error, block_job_cb, bs, &local_err); if (local_err) { error_propagate(errp, local_err); - return; + goto out; } trace_qmp_block_stream(bs, bs->job); + +out: + aio_context_release(aio_context); } void qmp_block_commit(const char *device, -- 1.9.3