md: Avoid OOPS when reshaping raid1 to raid0
raid1 arrays do not have the notion of chunk size. Calculate the
largest chunk sector size we can use to avoid a divide by zero OOPS
when aligning the size of the new array to the chunk size.
Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index c980945..de63a1f 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -632,6 +632,7 @@
static void *raid0_takeover_raid1(struct mddev *mddev)
{
struct r0conf *priv_conf;
+ int chunksect;
/* Check layout:
* - (N - 1) mirror drives must be already faulty
@@ -642,10 +643,25 @@
return ERR_PTR(-EINVAL);
}
+ /*
+ * a raid1 doesn't have the notion of chunk size, so
+ * figure out the largest suitable size we can use.
+ */
+ chunksect = 64 * 2; /* 64K by default */
+
+ /* The array must be an exact multiple of chunksize */
+ while (chunksect && (mddev->array_sectors & (chunksect - 1)))
+ chunksect >>= 1;
+
+ if ((chunksect << 9) < PAGE_SIZE)
+ /* array size does not allow a suitable chunk size */
+ return ERR_PTR(-EINVAL);
+
/* Set new parameters */
mddev->new_level = 0;
mddev->new_layout = 0;
- mddev->new_chunk_sectors = 128; /* by default set chunk size to 64k */
+ mddev->new_chunk_sectors = chunksect;
+ mddev->chunk_sectors = chunksect;
mddev->delta_disks = 1 - mddev->raid_disks;
mddev->raid_disks = 1;
/* make sure it will be not marked as dirty */