Function vdev_metaslab_init

freebsd/contrib/openzfs/module/zfs/vdev.c:1339–1434

}

int
vdev_metaslab_init(vdev_t *vd, uint64_t txg)
{
	spa_t *spa = vd->vdev_spa;
	objset_t *mos = spa->spa_meta_objset;
	uint64_t m;
	uint64_t oldc = vd->vdev_ms_count;
	uint64_t newc = vd->vdev_asize >> vd->vdev_ms_shift;
	metaslab_t **mspp;
	int error;
	boolean_t expanding = (oldc != 0);

	ASSERT(txg == 0 || spa_config_held(spa, SCL_ALLOC, RW_WRITER));

	/*
	 * This vdev is not being allocated from yet or is a hole.
	 */
	if (vd->vdev_ms_shift == 0)
		return (0);

	ASSERT(!vd->vdev_ishole);

	ASSERT(oldc <= newc);

	mspp = vmem_zalloc(newc * sizeof (*mspp), KM_SLEEP);

	if (expanding) {
		bcopy(vd->vdev_ms, mspp, oldc * sizeof (*mspp));
		vmem_free(vd->vdev_ms, oldc * sizeof (*mspp));
	}

	vd->vdev_ms = mspp;
	vd->vdev_ms_count = newc;
	for (m = oldc; m < newc; m++) {
		uint64_t object = 0;

		/*
		 * vdev_ms_array may be 0 if we are creating the "fake"
		 * metaslabs for an indirect vdev for zdb's leak detection.
		 * See zdb_leak_init().
		 */
		if (txg == 0 && vd->vdev_ms_array != 0) {
			error = dmu_read(mos, vd->vdev_ms_array,
			    m * sizeof (uint64_t), sizeof (uint64_t), &object,
			    DMU_READ_PREFETCH);
			if (error != 0) {
				vdev_dbgmsg(vd, "unable to read the metaslab "
				    "array [error=%d]", error);
				return (error);
			}
		}

#ifndef _KERNEL
		/*
		 * To accommodate zdb_leak_init() fake indirect
		 * metaslabs, we allocate a metaslab group for
		 * indirect vdevs which normally don't have one.
		 */