Grow: allow metadata to indicate that changing data_offset not supported.

If space_after and space_before are zero (the default) then assume that
metadata doesn't support changing data_offset.

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

1 files changed, 5 insertions, 0 deletions

diff --git a/Grow.c b/Grow.c
index 24bf6a9b..3bd0b3ed 100644
--- a/Grow.c
+++ b/Grow.c
@@ -2179,6 +2179,11 @@ static int set_new_data_offset(struct mdinfo *sra, struct supertype *st,
 		st2->ss->getinfo_super(st2, &info2, NULL);
 		st2->ss->free_super(st2);
 		free(st2);
+		if (info2.space_before == 0 &&
+		    info2.space_after == 0) {
+			/* Metadata doesn't support data_offset changes */
+			return 1;
+		}
 		if (delta_disks < 0) {
 			/* Don't need any space as array is shrinking
 			 * just move data_offset up by min