md: reject a re-add request that cannot be honoured.
The 'add_new_disk' ioctl can be used to add a device either as a
spare, or as an active disk that just needs to be resynced based on
write-intent-bitmap information (re-add)
Currently if a re-add is requested but fails we add as a spare
instead. This makes it impossible for user-space to check for
failure.
So change to require that a re-add attempt will either succeed or
completely fail. User-space can then decide what to do next.
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 4a4c0f8..5469ae3 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -5216,6 +5216,16 @@
} else
super_types[mddev->major_version].
validate_super(mddev, rdev);
+ if ((info->state & (1<<MD_DISK_SYNC)) &&
+ (!test_bit(In_sync, &rdev->flags) ||
+ rdev->raid_disk != info->raid_disk)) {
+ /* This was a hot-add request, but events doesn't
+ * match, so reject it.
+ */
+ export_rdev(rdev);
+ return -EINVAL;
+ }
+
if (test_bit(In_sync, &rdev->flags))
rdev->saved_raid_disk = rdev->raid_disk;
else