dm integrity: correctly calculate the size of metadata area

When we use separate devices for data and metadata, dm-integrity would
incorrectly calculate the size of the metadata device as if it had
512-byte block size - and it would refuse activation with larger block
size and smaller metadata device.

Fix this so that it takes actual block size into account, which fixes
the following reported issue:
https://gitlab.com/cryptsetup/cryptsetup/issues/450

Fixes: 356d9d52 ("dm integrity: allow separate metadata device")
Cc: stable@vger.kernel.org # v4.19+
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

drivers/md/dm-integrity.c

@@ -2568,7 +2568,7 @@ static int calculate_device_limits(struct dm_integrity_c *ic)
 		if (last_sector < ic->start || last_sector >= ic->meta_device_sectors)
 			return -EINVAL;
 	} else {
-		__u64 meta_size = ic->provided_data_sectors * ic->tag_size;
+		__u64 meta_size = (ic->provided_data_sectors >> ic->sb->log2_sectors_per_block) * ic->tag_size;
 		meta_size = (meta_size + ((1U << (ic->log2_buffer_sectors + SECTOR_SHIFT)) - 1))
 				>> (ic->log2_buffer_sectors + SECTOR_SHIFT);
 		meta_size <<= ic->log2_buffer_sectors;
@@ -3439,7 +3439,7 @@ static int dm_integrity_ctr(struct dm_target *ti, unsigned argc, char **argv)
 	DEBUG_print("	journal_sections %u\n", (unsigned)le32_to_cpu(ic->sb->journal_sections));
 	DEBUG_print("	journal_entries %u\n", ic->journal_entries);
 	DEBUG_print("	log2_interleave_sectors %d\n", ic->sb->log2_interleave_sectors);
-	DEBUG_print("	device_sectors 0x%llx\n", (unsigned long long)ic->device_sectors);
+	DEBUG_print("	data_device_sectors 0x%llx\n", (unsigned long long)ic->data_device_sectors);
 	DEBUG_print("	initial_sectors 0x%x\n", ic->initial_sectors);
 	DEBUG_print("	metadata_run 0x%x\n", ic->metadata_run);
 	DEBUG_print("	log2_metadata_run %d\n", ic->log2_metadata_run);