RE: [PATCH v2] exfat: do not clear VolumeDirty in writeback

[Yuezhang.Mo@xxxxxxxx]

Hi T.Kohada,

> > exfat_clear_volume_dirty() is only called in sync or umount context.
> > In sync or umount context, all requests will be issued with REQ_SYNC
> > regardless of whether REQ_SYNC is set when submitting buffer.
> >
> > And since the request of set VolumeDirty is issued with REQ_SYNC. So
> > for simplicity, call sync_dirty_buffer() unconditionally.
> 
> REQ_FUA and REQ_PREFLUSH may not make much sense on SD cards or USB
> sticks.
> However, the behavior of SCSI/ATAPI type devices with lazy write cache is
>  - Issue the SYNCHRONIZE_CACHE command to write all the data to the
> medium.
>  - Issue a WRITE command with FORCE_UNIT_ACCESS (device does not use
> write cache) for the boot sector.
> This guarantees a strict write order.

Thank you for your detailed explanation.
I will update my patch.

Best Regards,
Yuezhang Mo