UBIFS: fix division by zero

 */

long long ubifs_reported_space(const struct ubifs_info *c, uint64_t free)

{

	int divisor, factor;

	int divisor, factor, f;

	/*

	 * Reported space size is @free * X, where X is UBIFS block size

	 * divided by UBIFS block size + all overhead one data block

	 * introduces. The overhead is the node header + indexing overhead.

	 *

	 * Indexing overhead is calculations are based on the following

	 * formula: I = N/(f - 1) + 1, where I - number of indexing nodes, N -

	 * number of data nodes, f - fanout. Because effective UBIFS fanout is

	 * twice as less than maximum fanout, we assume that each data node

	 * Indexing overhead calculations are based on the following formula:

	 * I = N/(f - 1) + 1, where I - number of indexing nodes, N - number

	 * of data nodes, f - fanout. Because effective UBIFS fanout is twice

	 * as less than maximum fanout, we assume that each data node

	 * introduces 3 * @c->max_idx_node_sz / (@c->fanout/2 - 1) bytes.

	 * Note, the multiplier 3 is because UBIFS reseves thrice as more space

	 * for the index.

	 */

	f = c->fanout > 3 ? c->fanout >> 1 : 2;

	factor = UBIFS_BLOCK_SIZE;

	divisor = UBIFS_MAX_DATA_NODE_SZ;

	divisor += (c->max_idx_node_sz * 3) / ((c->fanout >> 1) - 1);

	divisor += (c->max_idx_node_sz * 3) / (f - 1);

	free *= factor;

	do_div(free, divisor);

	return free;