Implement a new type of zfs receive: corrective receive (-c)

This type of recv is used to heal corrupted data when a replica
of the data already exists (in the form of a send file for example).
With the provided send stream, corrective receive will read from
disk blocks described by the WRITE records. When any of the reads
come back with ECKSUM we use the data from the corresponding WRITE
record to rewrite the corrupted block.

Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Paul Zuchowski <pzuchowski@datto.com>
Signed-off-by: Alek Pinchuk <apinchuk@axcient.com>
Closes #9372

include/sys/spa.h

@@ -26,10 +26,10 @@
  * Copyright 2013 Saso Kiselkov. All rights reserved.
  * Copyright (c) 2014 Integros [integros.com]
  * Copyright 2017 Joyent, Inc.
- * Copyright (c) 2017, 2019, Datto Inc. All rights reserved.
  * Copyright (c) 2017, Intel Corporation.
  * Copyright (c) 2019, Allan Jude
  * Copyright (c) 2019, Klara Inc.
+ * Copyright (c) 2019, Datto Inc.
  */
 
 #ifndef _SYS_SPA_H
@@ -1134,6 +1134,7 @@ extern const char *spa_state_to_name(spa_t *spa);
 /* error handling */
 struct zbookmark_phys;
 extern void spa_log_error(spa_t *spa, const zbookmark_phys_t *zb);
+extern void spa_remove_error(spa_t *spa, zbookmark_phys_t *zb);
 extern int zfs_ereport_post(const char *clazz, spa_t *spa, vdev_t *vd,
     const zbookmark_phys_t *zb, zio_t *zio, uint64_t state);
 extern boolean_t zfs_ereport_is_valid(const char *clazz, spa_t *spa, vdev_t *vd,