[Devel] [RFC PATCH vz9 v6 56/62] dm-ploop: support REQ_FUA for data pios

[Andrey Zhadchenko]

On 12/13/24 14:12, Alexander Atanasov wrote:
> On 13.12.24 14:58, Andrey Zhadchenko wrote:
>> No, REQ_FUA does not oblige us to make sync. REQ_FUA is translated 
>> into IOCB_DSYNC. It is IOCB layer job to datasync this exact request.
>> Also REQ_FUA usually is coupled with REQ_PREFLUSH and we already 
>> handle that.
>>
> 
> We do this only for metadata in previous patches - pure data pios do not 
> handle it. And you are right about REQ_PREFLUSH but i think the vfs 
> layer will handle it along the sync - which is translated to PREFLUSH+FUA
> 

I think in "[RFC PATCH vz9 v6 17/62] dm-ploop: set IOCB_DSYNC on all FUA 
requests" we just save rq->cmd_flags and set IOCB_DSYNC if initial 
request contained REQ_FUA. Does this not cover pure data pios?

I suppose you are talking about an extra code to mark piwb if one of 
data pios with REQ_FUA triggered metadata change.