On 09/09/2012 04:34 PM, Arvydas Sidorenko wrote:

quoted

Meanwhile there already has a number of SATA disks that have supported
this feature.  So I think maybe we can enable it.

Regards,
Zheng

Blindly enabling FUA by default in my opinion is not a good idea at all.
I believe the focus should be on detecting FUA support on the device
instead, which the kernel at this point cannot reliably do (is it possible?).

Premature assumptions.  It is entirely possible that FUA is detected 
accurately, but the software is missing a flush somewhere that FUA 
requires, if disks are to be used in FUA mode.

The filesystem and the block layer must properly generate and order 
their I/Os based on the FUA enablement bits that appear in the block 
layer after libata discovers the SATA FUA feature.

	Jeff