[PATCH v2] xfs: avoid underflow in xfs_ioc_trim()

[Lukáš Czerner]

On Fri, 12 Oct 2012, Dave Chinner wrote:

> Date: Fri, 12 Oct 2012 08:35:33 +1100
> From: Dave Chinner <david at fromorbit.com>
> To: Lukas Czerner <lczerner at redhat.com>
> Cc: xfs at oss.sgi.com
> Subject: Re: [PATCH v2] xfs: avoid underflow in xfs_ioc_trim()
> 
> On Thu, Oct 11, 2012 at 10:33:52AM +0200, Lukas Czerner wrote:
> > Currently if len argument in xfs_ioc_trim() is smaller than one FSB
> > the 'end' variable underflow. Avoid that by returning EINVAL when
> > range is smaller than FSB.
> > 
> > Signed-off-by: Lukas Czerner <lczerner at redhat.com>
> 
> Just a thought - wouldn't this be better done at the VFS so it is
> consistent across all filesystems? i.e. using inode->i_blkbits?
> 
> Cheers,
> 
> Dave.

Currently I am working on patches for other file system, so we'll
get it fix. Having the check in VFS would require to make FITRIM
file system (inode?) operation, or adding cmd specific sections to
the vfs_ioctl(). All of this just for one check and file system
implementation would have to do other check anyway because we can
hardly do all of that in VFS. So I think it's not worth it.

Thanks!
-Lukas