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Re: [Qemu-devel] [PATCH for-2.9 1/5] block: Fix unpaired aio_disable_ext
From: |
Fam Zheng |
Subject: |
Re: [Qemu-devel] [PATCH for-2.9 1/5] block: Fix unpaired aio_disable_external in external snapshot |
Date: |
Fri, 7 Apr 2017 07:38:56 +0800 |
User-agent: |
Mutt/1.8.0 (2017-02-23) |
On Thu, 04/06 16:36, Kevin Wolf wrote:
> Am 06.04.2017 um 16:25 hat Fam Zheng geschrieben:
> > bdrv_replace_child_noperm tries to hand over the quiesce_counter state
> > from old bs to the new one, but if they are not on the same aio context
> > this causes unbalance.
> >
> > Fix this by forcing callers to move the aio context first, and assert
> > it.
> >
> > Reported-by: Ed Swierk <address@hidden>
> > Signed-off-by: Fam Zheng <address@hidden>
> > ---
> > block.c | 3 +++
> > blockdev.c | 4 ++--
> > 2 files changed, 5 insertions(+), 2 deletions(-)
> >
> > diff --git a/block.c b/block.c
> > index 927ba89..8893ac1 100644
> > --- a/block.c
> > +++ b/block.c
> > @@ -1752,6 +1752,9 @@ static void bdrv_replace_child_noperm(BdrvChild
> > *child,
> > {
> > BlockDriverState *old_bs = child->bs;
> >
> > + if (old_bs && new_bs) {
> > + assert(bdrv_get_aio_context(old_bs) ==
> > bdrv_get_aio_context(new_bs));
> > + }
> > if (old_bs) {
> > if (old_bs->quiesce_counter && child->role->drained_end) {
> > child->role->drained_end(child);
>
> Can we move this to a separate patch and also add this hunk for
> asserting the same thing for newly attached child nodes:
>
> @@ -1852,6 +1855,7 @@ BdrvChild *bdrv_attach_child(BlockDriverState
> *parent_bs,
> bdrv_get_cumulative_perm(parent_bs, &perm, &shared_perm);
>
> assert(parent_bs->drv);
> + assert(bdrv_get_aio_context(parent_bs) ==
> bdrv_get_aio_context(child_bs));
> parent_bs->drv->bdrv_child_perm(parent_bs, NULL, child_role,
> perm, shared_perm, &perm, &shared_perm);
OK, will do.