[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH v5] blockdev: acquire aio_context for bitmap add
Re: [Qemu-devel] [PATCH v5] blockdev: acquire aio_context for bitmap add/remove
Tue, 19 Feb 2019 08:59:47 -0600
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.0
On 2/18/19 5:31 PM, John Snow wrote:
> When bitmaps are persistent, they may incur a disk read or write when bitmaps
> are added or removed. For configurations like virtio-dataplane, failing to
> acquire this lock will abort QEMU when disk IO occurs.
> We used to acquire aio_context as part of the bitmap lookup, so re-introduce
> the lock for just the cases that have an IO penalty. Commit 2119882c removed
> these locks, and I failed to notice this when we committed fd5ae4cc, so this
> has been broken since persistent bitmaps were introduced.
> Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1672010
> Reported-By: Aihua Liang <address@hidden>
> Signed-off-by: John Snow <address@hidden>
> v5: I'm having a really bad day. This version actually has the semicolon.
> blockdev.c | 26 ++++++++++++++++++++------
> 1 file changed, 20 insertions(+), 6 deletions(-)
Reviewed-by: Eric Blake <address@hidden>
and yes, this time it builds.
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3226
Virtualization: qemu.org | libvirt.org