Kindly ping. Any comments and reviews are wellcome :) Thanks, Jiahui
On 2021/2/5 18:13, 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. > > v4->v5: > * Add document for 'retry' in qapi. > * Support werror=/rerror=retry for scsi-disk. > * Pause retry when draining. > > 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 > > Jiahui Cen (9): > 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 > scsi-bus: Refactor the code that retries requests > scsi-disk: Add support for retry on errors > > block/block-backend.c | 68 ++++++++++++++++++++ > blockdev.c | 52 +++++++++++++++ > hw/block/block.c | 10 +++ > hw/block/virtio-blk.c | 21 +++++- > hw/scsi/scsi-bus.c | 16 +++-- > hw/scsi/scsi-disk.c | 16 +++++ > include/hw/block/block.h | 7 +- > include/hw/scsi/scsi.h | 1 + > include/sysemu/block-backend.h | 10 +++ > qapi/block-core.json | 9 ++- > 10 files changed, 199 insertions(+), 11 deletions(-) >