Function vdev_draid_cksum_report

freebsd/contrib/openzfs/module/zfs/vdev_draid.c:809–866

* Invoked indirectly by zfs_ereport_start_checksum(), called * below when our read operation fails completely. The main point * is to keep a copy of everything we read from disk, so that at * vdev_draid_cksum_finish() time we can compare it with the good data. */

 * vdev_draid_cksum_finish() time we can compare it with the good data.
 */
static void
vdev_draid_cksum_report(zio_t *zio, zio_cksum_report_t *zcr, void *arg)
{
	size_t c = (size_t)(uintptr_t)arg;
	raidz_map_t *rm = zio->io_vsd;

	/* set up the report and bump the refcount  */
	zcr->zcr_cbdata = rm;
	zcr->zcr_cbinfo = c;
	zcr->zcr_finish = vdev_draid_cksum_finish;
	zcr->zcr_free = vdev_draid_cksum_free;

	rm->rm_reports++;
	ASSERT3U(rm->rm_reports, >, 0);

	if (rm->rm_row[0]->rr_abd_copy != NULL)
		return;

	/*
	 * It's the first time we're called for this raidz_map_t, so we need
	 * to copy the data aside; there's no guarantee that our zio's buffer
	 * won't be re-used for something else.
	 *
	 * Our parity data is already in separate buffers, so there's no need
	 * to copy them.  Furthermore, all columns should have been expanded
	 * by vdev_draid_map_alloc_empty() when attempting reconstruction.
	 */
	for (int i = 0; i < rm->rm_nrows; i++) {
		raidz_row_t *rr = rm->rm_row[i];
		size_t offset = 0;
		size_t size = 0;

		for (c = rr->rr_firstdatacol; c < rr->rr_cols; c++) {
			ASSERT3U(rr->rr_col[c].rc_size, ==,
			    rr->rr_col[0].rc_size);
			size += rr->rr_col[c].rc_size;
		}

		rr->rr_abd_copy = abd_alloc_for_io(size, B_FALSE);

		for (c = rr->rr_firstdatacol; c < rr->rr_cols; c++) {
			raidz_col_t *col = &rr->rr_col[c];
			abd_t *tmp = abd_get_offset_size(rr->rr_abd_copy,
			    offset, col->rc_size);

			abd_copy(tmp, col->rc_abd, col->rc_size);

			if (abd_is_gang(col->rc_abd))
				abd_free(col->rc_abd);
			else
				abd_put(col->rc_abd);

			col->rc_abd = tmp;
			offset += col->rc_size;
		}
		ASSERT3U(offset, ==, size);
	}
}