+static __u32 lod_gen_component_id(struct lod_object *lo,
+ int mirror_id, int comp_idx);
+
+/**
+ * Repeat an existing component
+ *
+ * Creates a new layout by replicating an existing component. Uses striping
+ * policy from previous component as a template for the striping for the new
+ * new component.
+ *
+ * New component starts with zero length, will be extended (or removed) before
+ * returning layout to client.
+ *
+ * NB: Reallocates layout components array (lo->ldo_comp_entries), invalidating
+ * any pre-existing pointers to components. Handle with care.
+ *
+ * \param[in] env execution environment for this thread
+ * \param[in,out] lo object to update the layout of
+ * \param[in] index index of component to copy
+ *
+ * \retval 0 on success
+ * \retval negative errno on error
+ */
+static int lod_layout_repeat_comp(const struct lu_env *env,
+ struct lod_object *lo, int index)
+{
+ struct lod_layout_component *lod_comp;
+ struct lod_layout_component *new_comp = NULL;
+ struct lod_layout_component *comp_array;
+ int rc = 0, i, new_cnt = lo->ldo_comp_cnt + 1;
+ __u16 mirror_id;
+ int offset = 0;
+ ENTRY;
+
+ lod_comp = &lo->ldo_comp_entries[index];
+ LASSERT(lod_comp_inited(lod_comp) && lod_comp->llc_id != LCME_ID_INVAL);
+
+ CDEBUG(D_LAYOUT, "repeating component %d\n", index);
+
+ OBD_ALLOC(comp_array, sizeof(*comp_array) * new_cnt);
+ if (comp_array == NULL)
+ GOTO(out, rc = -ENOMEM);
+
+ for (i = 0; i < lo->ldo_comp_cnt; i++) {
+ memcpy(&comp_array[i + offset], &lo->ldo_comp_entries[i],
+ sizeof(*comp_array));
+
+ /* Duplicate this component in to the next slot */
+ if (i == index) {
+ new_comp = &comp_array[i + 1];
+ memcpy(&comp_array[i + 1], &lo->ldo_comp_entries[i],
+ sizeof(*comp_array));
+ /* We must now skip this new component when copying */
+ offset = 1;
+ }
+ }
+
+ /* Set up copied component */
+ new_comp->llc_flags &= ~LCME_FL_INIT;
+ new_comp->llc_stripe = NULL;
+ new_comp->llc_stripes_allocated = 0;
+ new_comp->llc_stripe_offset = LOV_OFFSET_DEFAULT;
+ /* for uninstantiated components, layout gen stores default stripe
+ * offset */
+ new_comp->llc_layout_gen = lod_comp->llc_stripe_offset;
+ /* This makes the repeated component zero-length, placed at the end of
+ * the preceding component */
+ new_comp->llc_extent.e_start = new_comp->llc_extent.e_end;
+ new_comp->llc_timestamp = lod_comp->llc_timestamp;
+ new_comp->llc_pool = NULL;
+
+ rc = lod_set_pool(&new_comp->llc_pool, lod_comp->llc_pool);
+ if (rc)
+ GOTO(out, rc);
+
+ if (new_comp->llc_ostlist.op_array) {
+ __u32 *op_array = NULL;
+
+ OBD_ALLOC(op_array, new_comp->llc_ostlist.op_size);
+ if (!op_array)
+ GOTO(out, rc = -ENOMEM);
+ memcpy(op_array, &new_comp->llc_ostlist.op_array,
+ new_comp->llc_ostlist.op_size);
+ new_comp->llc_ostlist.op_array = op_array;
+ }
+
+ OBD_FREE(lo->ldo_comp_entries,
+ sizeof(*comp_array) * lo->ldo_comp_cnt);
+ lo->ldo_comp_entries = comp_array;
+ lo->ldo_comp_cnt = new_cnt;
+
+ /* Generate an id for the new component */
+ mirror_id = mirror_id_of(new_comp->llc_id);
+ new_comp->llc_id = LCME_ID_INVAL;
+ new_comp->llc_id = lod_gen_component_id(lo, mirror_id, index + 1);
+ if (new_comp->llc_id == LCME_ID_INVAL)
+ GOTO(out, rc = -ERANGE);
+
+ EXIT;
+out:
+ if (rc)
+ OBD_FREE(comp_array, sizeof(*comp_array) * new_cnt);
+
+ return rc;
+}
+