Fail safely when trying to grow an array with a write-intent bitmap.

We cannot currently change the size of a write-intent bitmap.
So if we change the size of an array which has such a bitmap, it
tries to set bits beyond the end of the bitmap.

For now, simply reject any request to change the size of an array
which has a bitmap.  mdadm can remove the bitmap and add a new one
after the array has changed size.

Signed-off-by: NeilBrown <neilb@suse.de>

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 8d11cd1..6eb9545 100644 (file)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -4639,6 +4639,11 @@ static int update_size(mddev_t *mddev, sector_t num_sectors)
         */
        if (mddev->sync_thread)
                return -EBUSY;
+       if (mddev->bitmap)
+               /* Sorry, cannot grow a bitmap yet, just remove it,
+                * grow, and re-add.
+                */
+               return -EBUSY;
        rdev_for_each(rdev, tmp, mddev) {
                sector_t avail;
                avail = rdev->size * 2;

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 40e9396..17e0953 100644 (file)
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -4446,6 +4446,9 @@ static int raid5_check_reshape(mddev_t *mddev)
                return -EINVAL; /* Cannot shrink array or change level yet */
        if (mddev->delta_disks == 0)
                return 0; /* nothing to do */
+       if (mddev->bitmap)
+               /* Cannot grow a bitmap yet */
+               return -EBUSY;
 
        /* Can only proceed if there are plenty of stripe_heads.
         * We need a minimum of one full stripe,, and for sensible progress