Re: RAID10 overwrites partition tables

[Felix Bellaby <member@bellaby.freeserve.co.uk>]

On Friday November 27, Neil Brown wrote
>>    	 mdadm --level 10 does not seem to respect disk partition boundaries.
> 
> Hmmm, yes, thanks.
>
> I think the following should fix the bug.  It only affects 'resync'
> not normal IO or recovery (after a drive has failed).
> ...
> diff ./drivers/md/raid10.c~current~ ./drivers/md/raid10.c
>  --- ./drivers/md/raid10.c~current~	2004-11-16 16:33:50.000000000 +1100
> +++ ./drivers/md/raid10.c	2004-11-27 11:00:06.000000000 +1100
> @@ -1150,6 +1150,7 @@ static void sync_request_write(mddev_t *
>  		md_sync_acct(conf->mirrors[d].rdev->bdev, tbio->bi_size >> 9);
>  
>  		tbio->bi_sector += conf->mirrors[d].rdev->data_offset;
> +		tbio->bi_bdev = conf->mirrors[d].rdev->bdev;
>  		generic_make_request(tbio);
>  	}
 
Thanks, the adjustments to the bio before the generic_make_request do the trick
nicely.

Note that the version of raid10.c in the current Fedora 3 series does not include
either of the adjustments so the patch required against that version becomes:

diff ./drivers/md/raid10.c~ ./drivers/md/raid10.c
 --- ./drivers/md/raid10.c~	2004-11-16 16:33:50.000000000 +1100
+++ ./drivers/md/raid10.c     2004-11-27 11:00:06.000000000 +1100
@@ -1145,6 +1145,8 @@
                atomic_inc(&r10_bio->remaining);
 		md_sync_acct(conf->mirrors[d].rdev->bdev, tbio->bi_size >> 9);
 
+	       tbio->bi_sector += conf->mirrors[d].rdev->data_offset;
+	       tbio->bi_bdev = conf->mirrors[d].rdev->bdev;
 	 	generic_make_request(tbio);
 	}

Thanks again,

Felix

 

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