Re: [PATCH v5 0/9] block: Add retry for werror=/rerror= mechanism

[Jiahui Cen]

Hi Stefan,

On 2021/2/23 17:40, Stefan Hajnoczi wrote:
> On Fri, Feb 05, 2021 at 06:13:06PM +0800, Jiahui Cen wrote:
>> 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.
> 
> This patch series implements a retry followed by werror/rerror=report
> after a timeout. This mechanism could be made more generic (and the code
> could be simplified) by removing the new werror/rerror=retry action and
> instead implementing the retry/timeout followed by *any* werror=/rerror=
> policy chosen by the user.
> 
> In other words, if the retry interval is non-zero, retry the request and
> check for timeouts. When the timeout is reached, obey the
> werror=/rerror= action.
> 
> This is more flexible than hard-coding werror=retry to mean retry
> timeout followed by werror=report.
> 
> For example:
> 
>   werror=stop,write-retry-interval=1000,write-retry-timeout=15000,
>   rerror=report,read-retry-interval=1000,read-retry-timeout=15000
> 
> Failed write requests will be retried once a second for 15 seconds.
> If the timeout is reached the guest is stopped.
> 
> Failed read requests will be retried once a second for 15 seconds. If
> the timeout is reached the error is reported to the guest.

Sounds like a better way for me. I'll refactor this patch series under
your suggestion.

Also thanks for your review.

Thanks,
Jiahui