Function dbuf_remap_impl

freebsd/contrib/openzfs/module/zfs/dbuf.c:4687–4736

}

static void
dbuf_remap_impl(dnode_t *dn, blkptr_t *bp, krwlock_t *rw, dmu_tx_t *tx)
{
	blkptr_t bp_copy = *bp;
	spa_t *spa = dmu_objset_spa(dn->dn_objset);
	dbuf_remap_impl_callback_arg_t drica;

	ASSERT(dsl_pool_sync_context(spa_get_dsl(spa)));

	drica.drica_os = dn->dn_objset;
	drica.drica_blk_birth = bp->blk_birth;
	drica.drica_tx = tx;
	if (spa_remap_blkptr(spa, &bp_copy, dbuf_remap_impl_callback,
	    &drica)) {
		/*
		 * If the blkptr being remapped is tracked by a livelist,
		 * then we need to make sure the livelist reflects the update.
		 * First, cancel out the old blkptr by appending a 'FREE'
		 * entry. Next, add an 'ALLOC' to track the new version. This
		 * way we avoid trying to free an inaccurate blkptr at delete.
		 * Note that embedded blkptrs are not tracked in livelists.
		 */
		if (dn->dn_objset != spa_meta_objset(spa)) {
			dsl_dataset_t *ds = dmu_objset_ds(dn->dn_objset);
			if (dsl_deadlist_is_open(&ds->ds_dir->dd_livelist) &&
			    bp->blk_birth > ds->ds_dir->dd_origin_txg) {
				ASSERT(!BP_IS_EMBEDDED(bp));
				ASSERT(dsl_dir_is_clone(ds->ds_dir));
				ASSERT(spa_feature_is_enabled(spa,
				    SPA_FEATURE_LIVELIST));
				bplist_append(&ds->ds_dir->dd_pending_frees,
				    bp);
				bplist_append(&ds->ds_dir->dd_pending_allocs,
				    &bp_copy);
			}
		}

		/*
		 * The db_rwlock prevents dbuf_read_impl() from
		 * dereferencing the BP while we are changing it.  To
		 * avoid lock contention, only grab it when we are actually
		 * changing the BP.
		 */
		if (rw != NULL)
			rw_enter(rw, RW_WRITER);
		*bp = bp_copy;
		if (rw != NULL)
			rw_exit(rw);
	}
}

/*
 * Remap any existing BP's to concrete vdevs, if possible.