Re: data corruption using raid0+lvm2+jfs with 2.6.0-test3

[Mike Fedyk <mfedyk@matchmail.com>]

On Wed, Aug 13, 2003 at 09:05:58AM +1000, Neil Brown wrote:
> On Tuesday August 12, akpm@osdl.org wrote:
> > Tupshin Harper <tupshin@tupshin.com> wrote:
> > >
> > > raid0_make_request bug: can't convert block across chunks or bigger than 
> > > 8k 12436792 8
> > 
> > There is a fix for this at
> > 
> > ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.0-test3/2.6.0-test3-mm1/broken-out/bio-too-big-fix.patch
> > 
> > Results of testing are always appreciated...
> 
> I don't think this will help.  It is a different problem.
> 
> As far as I can tell, the problem is that dm doesn't honour the
> merge_bvec_fn of the underlying device (neither does md for that
> matter).
> I think it does honour the max_sectors restriction, so it will only
> allow a request as big as one chunk, but it will allow such a requests
> to span a chunk boundary.
> 
> Probably the simplest solution to this is to put in calls to
> bio_split, which will need to be strengthed to handle multi-page bios.
> 
> The policy would be:
>   "a client of a block device *should* honour the various bio size 
>    restrictions, and may suffer performance loss if it doesn't;
>    a block device driver *must* handle any bio it is passed, and may
>    call bio_split to help out".
> 

Any progress on this?