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block: Drop out of coroutine in bdrv_do_drained_begin_quiesce() 

The next patch adds a parent drain to bdrv_attach_child_common(), which
shouldn't be, but is currently called from coroutines in some cases (e.g.
.bdrv_co_create implementations generally open new nodes). Therefore,
the assertion that we're not in a coroutine doesn't hold true any more.

We could just remove the assertion because there is nothing in the
function that should be in conflict with running in a coroutine, but
just to be on the safe side, we can reverse the caller relationship
between bdrv_do_drained_begin() and bdrv_do_drained_begin_quiesce() so
that the latter also just drops out of coroutine context and we can
still be certain in the future that any drain code doesn't run in
coroutines.

As a nice side effect, the structure of bdrv_do_drained_begin() is now
symmetrical with bdrv_do_drained_end().

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20221118174110.55183-14-kwolf@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Kevin Wolf 2022-11-18 18:41:08 +01:00
parent a82a3bd135
commit 05c272ff0c
1 changed files with 12 additions and 13 deletions
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25
block/io.c
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@ -346,10 +346,15 @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs,
}
}
void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, BdrvChild *parent)
static void bdrv_do_drained_begin(BlockDriverState *bs, BdrvChild *parent,
bool poll)
{
IO_OR_GS_CODE();
assert(!qemu_in_coroutine());
if (qemu_in_coroutine()) {
bdrv_co_yield_to_drain(bs, true, parent, poll);
return;
}
/* Stop things in parent-to-child order */
if (qatomic_fetch_inc(&bs->quiesce_counter) == 0) {
@ -359,17 +364,6 @@ void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, BdrvChild *parent)
bs->drv->bdrv_drain_begin(bs);
}
}
}
static void bdrv_do_drained_begin(BlockDriverState *bs, BdrvChild *parent,
bool poll)
{
if (qemu_in_coroutine()) {
bdrv_co_yield_to_drain(bs, true, parent, poll);
return;
}
bdrv_do_drained_begin_quiesce(bs, parent);
/*
* Wait for drained requests to finish.
@ -385,6 +379,11 @@ static void bdrv_do_drained_begin(BlockDriverState *bs, BdrvChild *parent,
}
}
void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, BdrvChild *parent)
{
bdrv_do_drained_begin(bs, parent, false);
}
void bdrv_drained_begin(BlockDriverState *bs)
{
IO_OR_GS_CODE();