Kindly ping for it. Thanks for Stefan's suggestion, we have re-implement the concept by introducing the 'retry' feature base on the werror=/rerror= mechanism.
Hope this thread won't be missed. Any comments and reviews are wellcome. Thanks. Ying Fang. On 12/15/2020 8:30 PM, 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 <cenjia...@huawei.com> Signed-off-by: Ying Fang <fangyi...@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(-)
