+++ /dev/null
-/*
- * Copyright (C) 2015 Andrea Mazzoleni
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- */
-
-#include "internal.h"
-#include "combo.h"
-#include "gf.h"
-
-/**
- * Validate the provided failed blocks.
- *
- * This function checks if the specified failed blocks satisfy the redundancy
- * information using the data from the known valid parity blocks.
- *
- * It's similar at raid_check(), just with a different format for arguments.
- *
- * The number of failed blocks @nr must be strictly less than the number of
- * parities @nv, because you need one more parity to validate the recovering.
- *
- * No data or parity blocks are modified.
- *
- * @nr Number of failed data blocks.
- * @id[] Vector of @nr indexes of the failed data blocks.
- * The indexes start from 0. They must be in order.
- * @nv Number of valid parity blocks.
- * @ip[] Vector of @nv indexes of the valid parity blocks.
- * The indexes start from 0. They must be in order.
- * @nd Number of data blocks.
- * @size Size of the blocks pointed by @v. It must be a multipler of 64.
- * @v Vector of pointers to the blocks of data and parity.
- * It has (@nd + @ip[@nv - 1] + 1) elements. The starting elements are the
- * blocks for data, following with the parity blocks.
- * Each block has @size bytes.
- * @return 0 if the check is satisfied. -1 otherwise.
- */
-static int raid_validate(int nr, int *id, int nv, int *ip, int nd, size_t size, void **vv)
-{
- uint8_t **v = (uint8_t **)vv;
- const uint8_t *T[RAID_PARITY_MAX][RAID_PARITY_MAX];
- uint8_t G[RAID_PARITY_MAX * RAID_PARITY_MAX];
- uint8_t V[RAID_PARITY_MAX * RAID_PARITY_MAX];
- size_t i;
- int j, k, l;
-
- BUG_ON(nr >= nv);
-
- /* setup the coefficients matrix */
- for (j = 0; j < nr; ++j)
- for (k = 0; k < nr; ++k)
- G[j * nr + k] = A(ip[j], id[k]);
-
- /* invert it to solve the system of linear equations */
- raid_invert(G, V, nr);
-
- /* get multiplication tables */
- for (j = 0; j < nr; ++j)
- for (k = 0; k < nr; ++k)
- T[j][k] = table(V[j * nr + k]);
-
- /* check all positions */
- for (i = 0; i < size; ++i) {
- uint8_t p[RAID_PARITY_MAX];
-
- /* get parity */
- for (j = 0; j < nv; ++j)
- p[j] = v[nd + ip[j]][i];
-
- /* compute delta parity, skipping broken disks */
- for (j = 0, k = 0; j < nd; ++j) {
- uint8_t b;
-
- /* skip broken disks */
- if (k < nr && id[k] == j) {
- ++k;
- continue;
- }
-
- b = v[j][i];
- for (l = 0; l < nv; ++l)
- p[l] ^= gfmul[b][gfgen[ip[l]][j]];
- }
-
- /* reconstruct data */
- for (j = 0; j < nr; ++j) {
- uint8_t b = 0;
- int idj = id[j];
-
- /* recompute the data */
- for (k = 0; k < nr; ++k)
- b ^= T[j][k][p[k]];
-
- /* add the parity contribution of the reconstructed data */
- for (l = nr; l < nv; ++l)
- p[l] ^= gfmul[b][gfgen[ip[l]][idj]];
- }
-
- /* check that the final parity is 0 */
- for (l = nr; l < nv; ++l)
- if (p[l] != 0)
- return -1;
- }
-
- return 0;
-}
-
-int raid_check(int nr, int *ir, int nd, int np, size_t size, void **v)
-{
- /* valid parity index */
- int ip[RAID_PARITY_MAX];
- int vp;
- int rd;
- int i, j;
-
- /* enforce limit on size */
- BUG_ON(size % 64 != 0);
-
- /* enforce limit on number of failures */
- BUG_ON(nr >= np); /* >= because we check with extra parity */
- BUG_ON(np > RAID_PARITY_MAX);
-
- /* enforce order in index vector */
- BUG_ON(nr >= 2 && ir[0] >= ir[1]);
- BUG_ON(nr >= 3 && ir[1] >= ir[2]);
- BUG_ON(nr >= 4 && ir[2] >= ir[3]);
- BUG_ON(nr >= 5 && ir[3] >= ir[4]);
- BUG_ON(nr >= 6 && ir[4] >= ir[5]);
-
- /* enforce limit on index vector */
- BUG_ON(nr > 0 && ir[nr-1] >= nd + np);
-
- /* count failed data disk */
- rd = 0;
- while (rd < nr && ir[rd] < nd)
- ++rd;
-
- /* put valid parities into ip[] */
- vp = 0;
- for (i = rd, j = 0; j < np; ++j) {
- /* if parity is failed */
- if (i < nr && ir[i] == nd + j) {
- /* skip broken parity */
- ++i;
- } else {
- /* store valid parity */
- ip[vp] = j;
- ++vp;
- }
- }
-
- return raid_validate(rd, ir, vp, ip, nd, size, v);
-}
-
-int raid_scan(int *ir, int nd, int np, size_t size, void **v)
-{
- int r;
-
- /* check the special case of no failure */
- if (np != 0 && raid_check(0, 0, nd, np, size, v) == 0)
- return 0;
-
- /* for each number of possible failures */
- for (r = 1; r < np; ++r) {
- /* try all combinations of r failures on n disks */
- combination_first(r, nd + np, ir);
- do {
- /* verify if the combination is a valid one */
- if (raid_check(r, ir, nd, np, size, v) == 0)
- return r;
- } while (combination_next(r, nd + np, ir));
- }
-
- /* no solution found */
- return -1;
-}
-
projects / bcachefs-tools-debian / blobdiff