Ping: [PATCH v4 0/7] block: Add retry for werror=/rerror= mechanism

[Jiahui Cen]

Hi Kevin,

What do you think of these patches?

Thanks,
Jiahui

On 2020/12/15 20:30, Jiahui Cen wrote:
> A VM in the cloud environment may use a virutal disk as the backend storage,
> and there are usually filesystems on the virtual block device. When backend
> storage is temporarily down, any I/O issued to the virtual block device
> will cause an error. For example, an error occurred in ext4 filesystem would
> make the filesystem readonly. In production environment, a cloud backend
> storage can be soon recovered. For example, an IP-SAN may be down due to
> network failure and will be online soon after network is recovered. However,
> the error in the filesystem may not be recovered unless a device reattach
> or system restart. Thus an I/O retry mechanism is in need to implement a
> self-healing system.
> 
> This patch series propose to extend the werror=/rerror= mechanism to add
> a 'retry' feature. It can automatically retry failed I/O requests on error
> without sending error back to guest, and guest can get back running smoothly
> when I/O is recovred.
> 
> v3->v4:
> * Adapt to werror=/rerror= mechanism.
> 
> v2->v3:
> * Add a doc to describe I/O hang.
> 
> v1->v2:
> * Rebase to fix compile problems.
> * Fix incorrect remove of rehandle list.
> * Provide rehandle pause interface.
> 
> REF: https://lists.gnu.org/archive/html/qemu-devel/2020-10/msg06560.html
> 
> Signed-off-by: Jiahui Cen <cenjiahui@huawei.com>
> Signed-off-by: Ying Fang <fangying1@huawei.com>
> 
> Jiahui Cen (7):
>   qapi/block-core: Add retry option for error action
>   block-backend: Introduce retry timer
>   block-backend: Add device specific retry callback
>   block-backend: Enable retry action on errors
>   block-backend: Add timeout support for retry
>   block: Add error retry param setting
>   virtio_blk: Add support for retry on errors
> 
>  block/block-backend.c          | 66 ++++++++++++++++++++
>  blockdev.c                     | 52 +++++++++++++++
>  hw/block/block.c               | 10 +++
>  hw/block/virtio-blk.c          | 19 +++++-
>  include/hw/block/block.h       |  7 ++-
>  include/sysemu/block-backend.h | 10 +++
>  qapi/block-core.json           |  4 +-
>  7 files changed, 162 insertions(+), 6 deletions(-)
>