BIO_FLUSH on twe driver. Why is it not there?

Pawel Jakub Dawidek pjd at
Fri Nov 2 03:21:22 PDT 2007

On Thu, Nov 01, 2007 at 10:41:00PM +0100, Dag-Erling Sm??rgrav wrote:
> "Artem Kuchin" <matrix at> writes:
> > However, twe is working via scsi subsystem and the authour of gjournal
> > said somewhere that he has had implemeneted BIO_FLISH for scsi and he
> > specifically mentioned that he has tested twe and twa and they both
> > support BIO_FLUSH.
> twa(4) uses CAM, but twe(4) doesn't (and never has).

That was my mistake. Someone told me (I think it was jhb@), that twe(4)
turns off write cache automatically when there is no battery, so
BIO_FLUSH isn't really needed and if there is a battery, it also isn't
really needed. It would be nice to hide the warning in this case
somehow, but for now you should be safe by simply ignoring the warning.

Pawel Jakub Dawidek             
pjd at                 
FreeBSD committer                         Am I Evil? Yes, I Am!
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