Re: [PATCH 1/2] Add discard/nodiscard mount option for ext3

[Lukas Czerner <lczerner@redhat.com>]

On Mon, 12 Jul 2010, Ric Wheeler wrote:

> On 07/12/2010 11:19 AM, Jan Kara wrote:
> > > Those mount option has the same meaning as in ext4 file system. It
> > > provide a way to enable/disable file system's trim support. The trim
> > > support is off by default, thus nodiscard option is not actually
> > > necessary.
> >    I kind of miss why ext3 should have a 'discard' mount option. When
> > user calls DISCARD ioctl on the filesystem, then he probably wants
> > discard to be performed.
> > 
> > 								Honza
> > 
> 
> Sorry I misunderstood your original question.
> 
> One reason that you might want to have a "discard" option is to allow a system
> admin to mount without barriers to protect flaky hardware (we have had some
> mixed results for example). As you say, the user probably wants to have the
> ioctl do the discard and should be reasonable for doing it only on solid
> devices,

The question is what in does on device other than SSD. I know it does
not harm the deivce, but is there some kernel logic preventing the trim
command to be send to device that does not support it ? I hope so.

-Lukas

> 
> Regards,
> 
> Ric
>