RE: Software raid0 will crash the file-system, when each disk is 5TB

On Wednesday May 16, david@lang.hm wrote:

On Thu, 17 May 2007, Neil Brown wrote:

quoted

On Thursday May 17, Jeff.Zheng@endace.com wrote:

quoted

quoted

The only difference of any significance between the working
and non-working configurations is that in the non-working,
the component devices are larger than 2Gig, and hence have
sector offsets greater than 32 bits.

Do u mean 2T here?, but in both configuartion, the component devices are
larger than 2T (2.25T&5.5T).

Yes, I meant 2T, and yes, the components are always over 2T.

2T decimal or 2T binary?

Either.  The smallest as actually 2.75T (typo above).
Precisely it was
  2929641472  kilobytes
or 
  5859282944 sectors
or 
  0x15D3D9000 sectors.

So it is over 32bits already...

Uhm, I just noticed something.
'chunk' is unsigned long, and when it gets shifted up, we might lose
bits.  That could still happen with the 4*2.75T arrangement, but is
much more likely in the 2*5.5T arrangement.

Jeff, can you try this patch?

Thanks.
NeilBrown


Signed-off-by: Neil Brown <redacted>

### Diffstat output
 ./drivers/md/raid0.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff .prev/drivers/md/raid0.c ./drivers/md/raid0.c

--- .prev/drivers/md/raid0.c	2007-05-17 10:33:30.000000000 +1000
+++ ./drivers/md/raid0.c	2007-05-17 15:02:15.000000000 +1000

@@ -475,7 +475,7 @@ static int raid0_make_request (request_q
 		x = block >> chunksize_bits;
 		tmp_dev = zone->dev[sector_div(x, zone->nb_dev)];
 	}
-	rsect = (((chunk << chunksize_bits) + zone->dev_offset)<<1)
+	rsect = ((((sector_t)chunk << chunksize_bits) + zone->dev_offset)<<1)
 		+ sect_in_chunk;
  
 	bio->bi_bdev = tmp_dev->bdev;