md/raid5: Allow reshape while a bitmap is present.

We always should have allowed this.  A raid5 reshape doesn't change
the size of the bitmap, so not need to restrict it.

Also add a test to make sure we don't try to start a reshape on a
failed array.

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

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index eab6168bb7f46fa5110369311de7dacdb732fa7a..8fba57e8f78becae1b1b0216e9a6526d26d9ebe2 100644 (file)
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -5559,9 +5559,6 @@ static int check_reshape(struct mddev *mddev)
            mddev->new_layout == mddev->layout &&
            mddev->new_chunk_sectors == mddev->chunk_sectors)
                return 0; /* nothing to do */
-       if (mddev->bitmap)
-               /* Cannot grow a bitmap yet */
-               return -EBUSY;
        if (has_failed(conf))
                return -EINVAL;
        if (mddev->delta_disks < 0) {
@@ -5596,6 +5593,9 @@ static int raid5_start_reshape(struct mddev *mddev)
        if (!check_stripe_cache(mddev))
                return -ENOSPC;
 
+       if (has_failed(conf))
+               return -EINVAL;
+
        rdev_for_each(rdev, mddev) {
                if (!test_bit(In_sync, &rdev->flags)
                    && !test_bit(Faulty, &rdev->flags))