block: Improve blk_revalidate_disk_zones() checks

Improves the checks on the zones of a zoned block device done in
blk_revalidate_disk_zones() by making sure that the device report_zones
method did report at least one zone and that the zones reported exactly
cover the entire disk capacity, that is, that there are no missing zones
at the end of the disk sector range.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-zoned.c

@@ -508,15 +508,29 @@ int blk_revalidate_disk_zones(struct gendisk *disk,
 	noio_flag = memalloc_noio_save();
 	ret = disk->fops->report_zones(disk, 0, UINT_MAX,
 				       blk_revalidate_zone_cb, &args);
+	if (!ret) {
+		pr_warn("%s: No zones reported\n", disk->disk_name);
+		ret = -ENODEV;
+	}
 	memalloc_noio_restore(noio_flag);
 
+	/*
+	 * If zones where reported, make sure that the entire disk capacity
+	 * has been checked.
+	 */
+	if (ret > 0 && args.sector != get_capacity(disk)) {
+		pr_warn("%s: Missing zones from sector %llu\n",
+			disk->disk_name, args.sector);
+		ret = -ENODEV;
+	}
+
 	/*
 	 * Install the new bitmaps and update nr_zones only once the queue is
 	 * stopped and all I/Os are completed (i.e. a scheduler is not
 	 * referencing the bitmaps).
 	 */
 	blk_mq_freeze_queue(q);
-	if (ret >= 0) {
+	if (ret > 0) {
 		blk_queue_chunk_sectors(q, args.zone_sectors);
 		q->nr_zones = args.nr_zones;
 		swap(q->seq_zones_wlock, args.seq_zones_wlock);