dm vdo: add repair of damaged vdo volumes

When a vdo is restarted after a crash, it will automatically attempt to
recover from its journals.

If a vdo encounters an unrecoverable error, it will enter read-only mode.
This mode indicates that some previously acknowledged data may have been
lost. The vdo may be instructed to rebuild as best it can in order to
return to a writable state. Although some data may be lost, this process
will ensure that the vdo's own metadata is self-consistent.
Co-developed-by: J. corwin Coburn <corwin@hurlbutnet.net>
Signed-off-by: J. corwin Coburn <corwin@hurlbutnet.net>
Co-developed-by: Michael Sclafani <dm-devel@lists.linux.dev>
Signed-off-by: Michael Sclafani <dm-devel@lists.linux.dev>
Co-developed-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Signed-off-by: Matthew Sakai <msakai@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

drivers/md/dm-vdo/repair.h

+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright 2023 Red Hat
+ */
+
+#ifndef VDO_REPAIR_H
+#define VDO_REPAIR_H
+
+#include "types.h"
+
+void vdo_replay_into_slab_journals(struct block_allocator *allocator, void *context);
+void vdo_repair(struct vdo_completion *parent);
+
+#endif /* VDO_REPAIR_H */