Re: 回复: [PATCH] xfs,fstrim: fix to return correct minlen

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Thu, Apr 11, 2019 at 02:05:08AM +0000, Wang Shilong wrote:
> Hi Darrick,
> 
> 
> On Wed, Apr 10, 2019 at 05:42:28PM +0900, Wang Shilong wrote:
> > From: Wang Shilong <wshilong@ddn.com>
> >
> > This patch tries to address two problems:
> >
> > 1) return @minlen we used to trim to
> > user space.
> >
> > 2) return EINVAL if granularity is larger than
> > avg size, even most of cases, granularity is small(4K),
> > but if devices return a lager granularity for some reaons
> > (testing, bugs etc), fstrim should return failure directly.
> 
> It really is a pity^W^Wannoying that there's no manual page for FITRIM,
> because I have no idea if this is the right or desired behavior for this
> ioctl.
> 
> Do the other filesystems update @minlen so that userspace knows the
> granularity?
> 
> --D
> 
> --------->
> As far as I checked ext4, f2fs, Btrfs did so,

Fair enough.

> I think it makes sense we return this value to userspace, we'd better
> to doc it somewhere 'man fstrim'?

Ok, please cc me when you send the documentation update.

--D

> thanks,
> Shilong