Messages in this thread | | | From | Neil Brown <> | Date | Thu, 17 May 2007 15:31:07 +1000 | Subject | RE: Software raid0 will crash the file-system, when each disk is 5TB |
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On Thursday May 17, neilb@suse.de wrote: > > 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.
Actually, it cannot be a problem with the 4*2.75T arrangement. chuck << chunksize_bits
will not exceed the size of the underlying device *in*kilobytes*. In that case that is 0xAE9EC800 which will git in a 32bit long. We don't double it to make sectors until after we add zone->dev_offset, which is "sector_t" and so 64bit arithmetic is used.
So I'm quite certain this bug will cause exactly the problems experienced!!
> > Jeff, can you try this patch?
Don't bother about the other tests I mentioned, just try this one. Thanks.
NeilBrown
> Signed-off-by: Neil Brown <neilb@suse.de> > > ### 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; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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