[PATCH 001 of 2] md: Fix two raid10 bugs.

[NeilBrown]

1/ When resyncing a degraded raid10 which has more than 2 copies of each block,
  garbage can get synced on top of good data.

2/ We round the wrong way in part of the device size calculation, which
  can cause confusion.

Signed-off-by: Neil Brown <neilb@xxxxxxx>
Cc: stable@xxxxxxxxxx

### Diffstat output
 ./drivers/md/raid10.c |    6 ++++++
 1 file changed, 6 insertions(+)

diff .prev/drivers/md/raid10.c ./drivers/md/raid10.c
--- .prev/drivers/md/raid10.c	2007-06-12 10:19:04.000000000 +1000
+++ ./drivers/md/raid10.c	2007-06-12 10:20:31.000000000 +1000
@@ -1866,6 +1866,7 @@ static sector_t sync_request(mddev_t *md
 			int d = r10_bio->devs[i].devnum;
 			bio = r10_bio->devs[i].bio;
 			bio->bi_end_io = NULL;
+			clear_bit(BIO_UPTODATE, &bio->bi_flags);
 			if (conf->mirrors[d].rdev == NULL ||
 			    test_bit(Faulty, &conf->mirrors[d].rdev->flags))
 				continue;
@@ -2036,6 +2037,11 @@ static int run(mddev_t *mddev)
 	/* 'size' is now the number of chunks in the array */
 	/* calculate "used chunks per device" in 'stride' */
 	stride = size * conf->copies;
+
+	/* We need to round up when dividing by raid_disks to
+	 * get the stride size.
+	 */
+	stride += conf->raid_disks - 1;
 	sector_div(stride, conf->raid_disks);
 	mddev->size = stride  << (conf->chunk_shift-1);
 
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