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Re: [Qemu-devel] [PATCH for-2.9 1/5] block: Fix unpaired aio_disable_ext
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-devel] [PATCH for-2.9 1/5] block: Fix unpaired aio_disable_external in external snapshot |
Date: |
Thu, 6 Apr 2017 16:36:07 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
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);
Kevin