int ubi_update_fastmap()

in ubi/fastmap.c [1538:1700]

• 134 lines of code
• 25 McCabe index (conditional complexity)

int ubi_update_fastmap(struct ubi_device *ubi)
{
	int ret, i, j;
	struct ubi_fastmap_layout *new_fm, *old_fm;
	struct ubi_wl_entry *tmp_e;

	down_write(&ubi->fm_protect);
	down_write(&ubi->work_sem);
	down_write(&ubi->fm_eba_sem);

	ubi_refill_pools(ubi);

	if (ubi->ro_mode || ubi->fm_disabled) {
		up_write(&ubi->fm_eba_sem);
		up_write(&ubi->work_sem);
		up_write(&ubi->fm_protect);
		return 0;
	}

	new_fm = kzalloc(sizeof(*new_fm), GFP_KERNEL);
	if (!new_fm) {
		up_write(&ubi->fm_eba_sem);
		up_write(&ubi->work_sem);
		up_write(&ubi->fm_protect);
		return -ENOMEM;
	}

	new_fm->used_blocks = ubi->fm_size / ubi->leb_size;
	old_fm = ubi->fm;
	ubi->fm = NULL;

	if (new_fm->used_blocks > UBI_FM_MAX_BLOCKS) {
		ubi_err(ubi, "fastmap too large");
		ret = -ENOSPC;
		goto err;
	}

	for (i = 1; i < new_fm->used_blocks; i++) {
		spin_lock(&ubi->wl_lock);
		tmp_e = ubi_wl_get_fm_peb(ubi, 0);
		spin_unlock(&ubi->wl_lock);

		if (!tmp_e) {
			if (old_fm && old_fm->e[i]) {
				ret = erase_block(ubi, old_fm->e[i]->pnum);
				if (ret < 0) {
					ubi_err(ubi, "could not erase old fastmap PEB");

					for (j = 1; j < i; j++) {
						ubi_wl_put_fm_peb(ubi, new_fm->e[j],
								  j, 0);
						new_fm->e[j] = NULL;
					}
					goto err;
				}
				new_fm->e[i] = old_fm->e[i];
				old_fm->e[i] = NULL;
			} else {
				ubi_err(ubi, "could not get any free erase block");

				for (j = 1; j < i; j++) {
					ubi_wl_put_fm_peb(ubi, new_fm->e[j], j, 0);
					new_fm->e[j] = NULL;
				}

				ret = -ENOSPC;
				goto err;
			}
		} else {
			new_fm->e[i] = tmp_e;

			if (old_fm && old_fm->e[i]) {
				ubi_wl_put_fm_peb(ubi, old_fm->e[i], i,
						  old_fm->to_be_tortured[i]);
				old_fm->e[i] = NULL;
			}
		}
	}

	/* Old fastmap is larger than the new one */
	if (old_fm && new_fm->used_blocks < old_fm->used_blocks) {
		for (i = new_fm->used_blocks; i < old_fm->used_blocks; i++) {
			ubi_wl_put_fm_peb(ubi, old_fm->e[i], i,
					  old_fm->to_be_tortured[i]);
			old_fm->e[i] = NULL;
		}
	}

	spin_lock(&ubi->wl_lock);
	tmp_e = ubi->fm_anchor;
	ubi->fm_anchor = NULL;
	spin_unlock(&ubi->wl_lock);

	if (old_fm) {
		/* no fresh anchor PEB was found, reuse the old one */
		if (!tmp_e) {
			ret = erase_block(ubi, old_fm->e[0]->pnum);
			if (ret < 0) {
				ubi_err(ubi, "could not erase old anchor PEB");

				for (i = 1; i < new_fm->used_blocks; i++) {
					ubi_wl_put_fm_peb(ubi, new_fm->e[i],
							  i, 0);
					new_fm->e[i] = NULL;
				}
				goto err;
			}
			new_fm->e[0] = old_fm->e[0];
			new_fm->e[0]->ec = ret;
			old_fm->e[0] = NULL;
		} else {
			/* we've got a new anchor PEB, return the old one */
			ubi_wl_put_fm_peb(ubi, old_fm->e[0], 0,
					  old_fm->to_be_tortured[0]);
			new_fm->e[0] = tmp_e;
			old_fm->e[0] = NULL;
		}
	} else {
		if (!tmp_e) {
			ubi_err(ubi, "could not find any anchor PEB");

			for (i = 1; i < new_fm->used_blocks; i++) {
				ubi_wl_put_fm_peb(ubi, new_fm->e[i], i, 0);
				new_fm->e[i] = NULL;
			}

			ret = -ENOSPC;
			goto err;
		}
		new_fm->e[0] = tmp_e;
	}

	ret = ubi_write_fastmap(ubi, new_fm);

	if (ret)
		goto err;

out_unlock:
	up_write(&ubi->fm_eba_sem);
	up_write(&ubi->work_sem);
	up_write(&ubi->fm_protect);
	kfree(old_fm);

	ubi_ensure_anchor_pebs(ubi);

	return ret;

err:
	ubi_warn(ubi, "Unable to write new fastmap, err=%i", ret);

	ret = invalidate_fastmap(ubi);
	if (ret < 0) {
		ubi_err(ubi, "Unable to invalidate current fastmap!");
		ubi_ro_mode(ubi);
	} else {
		return_fm_pebs(ubi, old_fm);
		return_fm_pebs(ubi, new_fm);
		ret = 0;
	}

	kfree(new_fm);
	goto out_unlock;
}