Implement brute-force error locator for EC

src/osd_rmw_test.cpp

@@ -28,6 +28,7 @@ void test14();
 void test15(bool second);
 void test16();
 void test_recover_22_d2();
+void test_ec42_error_bruteforce();
 
 int main(int narg, char *args[])
 {
@@ -64,6 +65,8 @@ int main(int narg, char *args[])
     test16();
     // Test 17
     test_recover_22_d2();
+    // Error bruteforce
+    test_ec42_error_bruteforce();
     // End
     printf("all ok\n");
     return 0;
@@ -1106,3 +1109,64 @@ void test_recover_22_d2()
     // Done
     use_ec(4, 2, false);
 }
+
+/***
+
+EC 4+2 error location bruteforce
+
+***/
+
+static void assert_eq_vec(const std::vector<int> & a, const std::vector<int> & b)
+{
+    printf("Expect [");
+    for (int i = 0; i < a.size(); i++)
+        printf(" %d", a[i]);
+    printf(" ] have [");
+    for (int i = 0; i < b.size(); i++)
+        printf(" %d", b[i]);
+    printf(" ]\n");
+    assert(a == b);
+}
+
+void test_ec42_error_bruteforce()
+{
+    use_ec(6, 4, true);
+    osd_num_t osd_set[6] = { 1, 2, 3, 4, 5, 6 };
+    osd_rmw_stripe_t stripes[6] = {};
+    split_stripes(4, 4096, 0, 4096 * 4, stripes);
+    uint8_t *write_buf = (uint8_t*)malloc_or_die(4096 * 6);
+    set_pattern(write_buf+0*4096, 4096, PATTERN0);
+    set_pattern(write_buf+1*4096, 4096, PATTERN1);
+    set_pattern(write_buf+2*4096, 4096, PATTERN2);
+    set_pattern(write_buf+3*4096, 4096, PATTERN3);
+    uint8_t *rmw_buf = (uint8_t*)calc_rmw(write_buf, stripes, osd_set, 6, 4, 6, osd_set, 4096, 0);
+    calc_rmw_parity_ec(stripes, 6, 4, osd_set, osd_set, 4096, 0);
+    check_pattern(stripes[4].write_buf, 4096, PATTERN0^PATTERN1^PATTERN2^PATTERN3);
+    check_pattern(stripes[5].write_buf, 4096, 0x139274739ae6f387); // 2nd EC chunk
+    memcpy(write_buf+4*4096, stripes[4].write_buf, 4096);
+    memcpy(write_buf+5*4096, stripes[5].write_buf, 4096);
+    // Try to locate errors
+    for (int i = 0; i < 6; i++)
+    {
+        stripes[i].read_start = 0;
+        stripes[i].read_end = 4096;
+        stripes[i].read_buf = write_buf+i*4096;
+        stripes[i].write_buf = NULL;
+    }
+    // All good chunks
+    auto res = ec_find_good(stripes, 6, 4, false, 4096, 0, 100);
+    assert_eq_vec(res, std::vector<int>({0, 1, 2, 3, 4, 5}));
+    // 1 missing chunk
+    set_pattern(write_buf+1*4096, 4096, 0);
+    res = ec_find_good(stripes, 6, 4, false, 4096, 0, 100);
+    assert_eq_vec(res, std::vector<int>({0, 2, 3, 4, 5}));
+    // 2 missing chunks
+    set_pattern(write_buf+1*4096, 4096, 0);
+    set_pattern(write_buf+5*4096, 4096, 0);
+    res = ec_find_good(stripes, 6, 4, false, 4096, 0, 100);
+    assert_eq_vec(res, std::vector<int>());
+    // Done
+    free(rmw_buf);
+    free(write_buf);
+    use_ec(6, 4, false);
+}