Grow/bitmap: support adding bitmap via sysfs.

Adding a bitmap via ioctl can only add it at a fixed location.
That location is not suitable for 4K-block devices.

So allow setting the bitmap location via sysfs if kernel supports it
and aim to always use 4K alignments.

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

1 files changed, 3 insertions, 0 deletions

diff --git a/super0.c b/super0.c
index f3d0c07c..dab85db8 100644
--- a/super0.c
+++ b/super0.c
@@ -360,6 +360,9 @@ static void getinfo_super0(struct supertype *st, struct mdinfo *info, char *map)
 	info->array.state = sb->state;
 	info->component_size = sb->size*2;
 
+	if (sb->state & (1<<MD_SB_BITMAP_PRESENT))
+		info->bitmap_offset = 8;
+
 	info->disk.state = sb->this_disk.state;
 	info->disk.major = sb->this_disk.major;
 	info->disk.minor = sb->this_disk.minor;