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mdadm/raid6check.c

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/*
* raid6check - extended consistency check for RAID-6
*
* Copyright (C) 2011 Piergiorgio Sartor
*
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Author: Piergiorgio Sartor
* Based on "restripe.c" from "mdadm" codebase
*/
#include "mdadm.h"
#include <stdint.h>
#include <sys/mman.h>
#define CHECK_PAGE_BITS (12)
#define CHECK_PAGE_SIZE (1 << CHECK_PAGE_BITS)
char const Name[] = "raid6check";
enum repair {
NO_REPAIR = 0,
MANUAL_REPAIR,
AUTO_REPAIR
};
int geo_map(int block, unsigned long long stripe, int raid_disks,
int level, int layout);
int is_ddf(int layout);
void qsyndrome(uint8_t *p, uint8_t *q, uint8_t **sources, int disks, int size);
void make_tables(void);
void ensure_zero_has_size(int chunk_size);
void raid6_datap_recov(int disks, size_t bytes, int faila, uint8_t **ptrs,
int neg_offset);
void raid6_2data_recov(int disks, size_t bytes, int faila, int failb,
uint8_t **ptrs, int neg_offset);
void xor_blocks(char *target, char **sources, int disks, int size);
/* Collect per stripe consistency information */
void raid6_collect(int chunk_size, uint8_t *p, uint8_t *q,
char *chunkP, char *chunkQ, int *results)
{
int i;
int data_id;
uint8_t Px, Qx;
extern uint8_t raid6_gflog[];
for(i = 0; i < chunk_size; i++) {
Px = (uint8_t)chunkP[i] ^ (uint8_t)p[i];
Qx = (uint8_t)chunkQ[i] ^ (uint8_t)q[i];
if((Px != 0) && (Qx == 0))
results[i] = -1;
if((Px == 0) && (Qx != 0))
results[i] = -2;
if((Px != 0) && (Qx != 0)) {
data_id = (raid6_gflog[Qx] - raid6_gflog[Px]);
if(data_id < 0) data_id += 255;
results[i] = data_id;
}
if((Px == 0) && (Qx == 0))
results[i] = -255;
}
}
/* Try to find out if a specific disk has problems in a CHECK_PAGE_SIZE page size */
int raid6_stats_blk(int *results, int raid_disks)
{
int i;
int curr_broken_disk = -255;
int prev_broken_disk = -255;
int broken_status = 0;
for(i = 0; i < CHECK_PAGE_SIZE; i++) {
if(results[i] != -255)
curr_broken_disk = results[i];
if(curr_broken_disk >= raid_disks)
broken_status = 2;
switch(broken_status) {
case 0:
if(curr_broken_disk != -255) {
prev_broken_disk = curr_broken_disk;
broken_status = 1;
}
break;
case 1:
if(curr_broken_disk != prev_broken_disk)
broken_status = 2;
break;
case 2:
default:
curr_broken_disk = prev_broken_disk = -65535;
break;
}
}
return curr_broken_disk;
}
/* Collect disks status for a strip in CHECK_PAGE_SIZE page size blocks */
void raid6_stats(int *disk, int *results, int raid_disks, int chunk_size)
{
int i, j;
for(i = 0, j = 0; i < chunk_size; i += CHECK_PAGE_SIZE, j++) {
disk[j] = raid6_stats_blk(&results[i], raid_disks);
}
}
int lock_stripe(struct mdinfo *info, unsigned long long start,
int chunk_size, int data_disks, sighandler_t *sig)
{
int rv;
sig[0] = signal_s(SIGTERM, SIG_IGN);
sig[1] = signal_s(SIGINT, SIG_IGN);
sig[2] = signal_s(SIGQUIT, SIG_IGN);
if (sig[0] == SIG_ERR || sig[1] == SIG_ERR || sig[2] == SIG_ERR)
return 1;
if(mlockall(MCL_CURRENT | MCL_FUTURE) != 0) {
return 2;
}
rv = sysfs_set_num(info, NULL, "suspend_lo", start * chunk_size * data_disks);
rv |= sysfs_set_num(info, NULL, "suspend_hi", (start + 1) * chunk_size * data_disks);
return rv * 256;
}
int unlock_all_stripes(struct mdinfo *info, sighandler_t *sig)
{
int rv;
rv = sysfs_set_num(info, NULL, "suspend_lo", 0x7FFFFFFFFFFFFFFFULL);
rv |= sysfs_set_num(info, NULL, "suspend_hi", 0);
rv |= sysfs_set_num(info, NULL, "suspend_lo", 0);
signal_s(SIGQUIT, sig[2]);
signal_s(SIGINT, sig[1]);
signal_s(SIGTERM, sig[0]);
if(munlockall() != 0)
return 3;
return rv * 256;
}
/* Autorepair */
int autorepair(int *disk, unsigned long long start, int chunk_size,
char *name[], int raid_disks, int syndrome_disks, char **blocks_page,
char **blocks, uint8_t *p, int *block_index_for_slot,
int *source, unsigned long long *offsets)
{
int i, j;
int pages_to_write_count = 0;
int page_to_write[chunk_size >> CHECK_PAGE_BITS];
for(j = 0; j < (chunk_size >> CHECK_PAGE_BITS); j++) {
if (disk[j] >= -2 && block_index_for_slot[disk[j]] >= 0) {
int slot = block_index_for_slot[disk[j]];
printf("Auto-repairing slot %d (%s)\n", slot, name[slot]);
pages_to_write_count++;
page_to_write[j] = 1;
for(i = -2; i < syndrome_disks; i++) {
blocks_page[i] = blocks[i] + j * CHECK_PAGE_SIZE;
}
if (disk[j] == -2) {
qsyndrome(p, (uint8_t*)blocks_page[-2],
(uint8_t**)blocks_page,
syndrome_disks, CHECK_PAGE_SIZE);
}
else {
char *all_but_failed_blocks[syndrome_disks];
for(i = 0; i < syndrome_disks; i++) {
if (i == disk[j])
all_but_failed_blocks[i] = blocks_page[-1];
else
all_but_failed_blocks[i] = blocks_page[i];
}
xor_blocks(blocks_page[disk[j]],
all_but_failed_blocks, syndrome_disks,
CHECK_PAGE_SIZE);
}
}
else {
page_to_write[j] = 0;
}
}
if(pages_to_write_count > 0) {
int write_res = 0;
for(j = 0; j < (chunk_size >> CHECK_PAGE_BITS); j++) {
if(page_to_write[j] == 1) {
int slot = block_index_for_slot[disk[j]];
lseek64(source[slot], offsets[slot] + start * chunk_size + j * CHECK_PAGE_SIZE, SEEK_SET);
write_res += write(source[slot],
blocks[disk[j]] + j * CHECK_PAGE_SIZE,
CHECK_PAGE_SIZE);
}
}
if (write_res != (CHECK_PAGE_SIZE * pages_to_write_count)) {
fprintf(stderr, "Failed to write a full chunk.\n");
return -1;
}
}
return 0;
}
/* Manual repair */
int manual_repair(int chunk_size, int syndrome_disks,
int failed_slot1, int failed_slot2,
unsigned long long start, int *block_index_for_slot,
char *name[], char **stripes, char **blocks, uint8_t *p,
int *source, unsigned long long *offsets)
{
int i;
int fd1 = block_index_for_slot[failed_slot1];
int fd2 = block_index_for_slot[failed_slot2];
printf("Repairing stripe %llu\n", start);
printf("Assuming slots %d (%s) and %d (%s) are incorrect\n",
fd1, name[fd1],
fd2, name[fd2]);
if (failed_slot1 == -2 || failed_slot2 == -2) {
char *all_but_failed_blocks[syndrome_disks];
int failed_data_or_p;
if (failed_slot1 == -2)
failed_data_or_p = failed_slot2;
else
failed_data_or_p = failed_slot1;
printf("Repairing D/P(%d) and Q\n", failed_data_or_p);
for (i = 0; i < syndrome_disks; i++) {
if (i == failed_data_or_p)
all_but_failed_blocks[i] = blocks[-1];
else
all_but_failed_blocks[i] = blocks[i];
}
xor_blocks(blocks[failed_data_or_p],
all_but_failed_blocks, syndrome_disks, chunk_size);
qsyndrome(p, (uint8_t*)blocks[-2], (uint8_t**)blocks,
syndrome_disks, chunk_size);
} else {
ensure_zero_has_size(chunk_size);
if (failed_slot1 == -1 || failed_slot2 == -1) {
int failed_data;
if (failed_slot1 == -1)
failed_data = failed_slot2;
else
failed_data = failed_slot1;
printf("Repairing D(%d) and P\n", failed_data);
raid6_datap_recov(syndrome_disks+2, chunk_size,
failed_data, (uint8_t**)blocks, 1);
} else {
printf("Repairing D and D\n");
raid6_2data_recov(syndrome_disks+2, chunk_size,
failed_slot1, failed_slot2,
(uint8_t**)blocks, 1);
}
}
int write_res1, write_res2;
off64_t seek_res;
seek_res = lseek64(source[fd1],
offsets[fd1] + start * chunk_size, SEEK_SET);
if (seek_res < 0) {
fprintf(stderr, "lseek failed for failed_disk1\n");
return -1;
}
write_res1 = write(source[fd1], blocks[failed_slot1], chunk_size);
seek_res = lseek64(source[fd2],
offsets[fd2] + start * chunk_size, SEEK_SET);
if (seek_res < 0) {
fprintf(stderr, "lseek failed for failed_disk2\n");
return -1;
}
write_res2 = write(source[fd2], blocks[failed_slot2], chunk_size);
if (write_res1 != chunk_size || write_res2 != chunk_size) {
fprintf(stderr, "Failed to write a complete chunk.\n");
return -2;
}
return 0;
}
int check_stripes(struct mdinfo *info, int *source, unsigned long long *offsets,
int raid_disks, int chunk_size, int level, int layout,
unsigned long long start, unsigned long long length, char *name[],
enum repair repair, int failed_disk1, int failed_disk2)
{
/* read the data and p and q blocks, and check we got them right */
int data_disks = raid_disks - 2;
int syndrome_disks = data_disks + is_ddf(layout) * 2;
char *stripe_buf;
/* stripes[] is indexed by raid_disk and holds chunks from each device */
char **stripes = xmalloc(raid_disks * sizeof(char*));
/* blocks[] is indexed by syndrome number and points to either one of the
* chunks from 'stripes[]', or to a chunk of zeros. -1 and -2 are
* P and Q */
char **blocks = xmalloc((syndrome_disks + 2) * sizeof(char*));
/* blocks_page[] is a temporary index to just one page of the chunks
* that blocks[] points to. */
char **blocks_page = xmalloc((syndrome_disks + 2) * sizeof(char*));
/* block_index_for_slot[] provides the reverse mapping from blocks to stripes.
* The index is a syndrome position, the content is a raid_disk number.
* indicies -1 and -2 work, and are P and Q disks */
int *block_index_for_slot = xmalloc((syndrome_disks+2) * sizeof(int));
/* 'p' and 'q' contain calcualted P and Q, to be compared with
* blocks[-1] and blocks[-2];
*/
uint8_t *p = xmalloc(chunk_size);
uint8_t *q = xmalloc(chunk_size);
char *zero = xmalloc(chunk_size);
int *results = xmalloc(chunk_size * sizeof(int));
sighandler_t *sig = xmalloc(3 * sizeof(sighandler_t));
int i, j;
int diskP, diskQ, diskD;
int err = 0;
extern int tables_ready;
if (!tables_ready)
make_tables();
if (posix_memalign((void**)&stripe_buf, 4096, raid_disks * chunk_size) != 0)
exit(4);
block_index_for_slot += 2;
blocks += 2;
blocks_page += 2;
memset(zero, 0, chunk_size);
for ( i = 0 ; i < raid_disks ; i++)
stripes[i] = stripe_buf + i * chunk_size;
while (length > 0) {
/* The syndrome number of the broken disk is recorded
* in 'disk[]' which allows a different broken disk for
* each page.
*/
int disk[chunk_size >> CHECK_PAGE_BITS];
err = lock_stripe(info, start, chunk_size, data_disks, sig);
if(err != 0) {
if (err != 2)
unlock_all_stripes(info, sig);
goto exitCheck;
}
for (i = 0 ; i < raid_disks ; i++) {
off64_t seek_res = lseek64(source[i], offsets[i] + start * chunk_size,
SEEK_SET);
if (seek_res < 0) {
fprintf(stderr, "lseek to source %d failed\n", i);
unlock_all_stripes(info, sig);
err = -1;
goto exitCheck;
}
int read_res = read(source[i], stripes[i], chunk_size);
if (read_res < chunk_size) {
fprintf(stderr, "Failed to read complete chunk disk %d, aborting\n", i);
unlock_all_stripes(info, sig);
err = -1;
goto exitCheck;
}
}
diskP = geo_map(-1, start, raid_disks, level, layout);
block_index_for_slot[-1] = diskP;
blocks[-1] = stripes[diskP];
diskQ = geo_map(-2, start, raid_disks, level, layout);
block_index_for_slot[-2] = diskQ;
blocks[-2] = stripes[diskQ];
if (!is_ddf(layout)) {
/* The syndrome-order of disks starts immediately after 'Q',
* but skips P */
diskD = diskQ;
for (i = 0 ; i < data_disks ; i++) {
diskD = diskD + 1;
if (diskD >= raid_disks)
diskD = 0;
if (diskD == diskP)
diskD += 1;
if (diskD >= raid_disks)
diskD = 0;
blocks[i] = stripes[diskD];
block_index_for_slot[i] = diskD;
}
} else {
/* The syndrome-order exactly follows raid-disk
* numbers, with ZERO in place of P and Q
*/
for (i = 0 ; i < raid_disks; i++) {
if (i == diskP || i == diskQ) {
blocks[i] = zero;
block_index_for_slot[i] = -1;
} else {
blocks[i] = stripes[i];
block_index_for_slot[i] = i;
}
}
}
qsyndrome(p, q, (uint8_t**)blocks, syndrome_disks, chunk_size);
raid6_collect(chunk_size, p, q, stripes[diskP], stripes[diskQ], results);
raid6_stats(disk, results, raid_disks, chunk_size);
for(j = 0; j < (chunk_size >> CHECK_PAGE_BITS); j++) {
int role = disk[j];
if (role >= -2) {
int slot = block_index_for_slot[role];
if (slot >= 0)
printf("Error detected at stripe %llu, page %d: possible failed disk slot %d: %d --> %s\n",
start, j, role, slot, name[slot]);
else
printf("Error detected at stripe %llu, page %d: failed slot %d should be zeros\n",
start, j, role);
} else if(disk[j] == -65535) {
printf("Error detected at stripe %llu, page %d: disk slot unknown\n", start, j);
}
}
if(repair == AUTO_REPAIR) {
err = autorepair(disk, start, chunk_size,
name, raid_disks, syndrome_disks, blocks_page,
blocks, p, block_index_for_slot,
source, offsets);
if(err != 0) {
unlock_all_stripes(info, sig);
goto exitCheck;
}
}
if(repair == MANUAL_REPAIR) {
int failed_slot1 = -1, failed_slot2 = -1;
for (i = -2; i < syndrome_disks; i++) {
if (block_index_for_slot[i] == failed_disk1)
failed_slot1 = i;
if (block_index_for_slot[i] == failed_disk2)
failed_slot2 = i;
}
err = manual_repair(chunk_size, syndrome_disks,
failed_slot1, failed_slot2,
start, block_index_for_slot,
name, stripes, blocks, p,
source, offsets);
if(err == -1) {
unlock_all_stripes(info, sig);
goto exitCheck;
}
}
err = unlock_all_stripes(info, sig);
if(err != 0) {
goto exitCheck;
}
length--;
start++;
}
exitCheck:
free(stripe_buf);
free(stripes);
free(blocks-2);
free(blocks_page-2);
free(block_index_for_slot-2);
free(p);
free(q);
free(results);
free(sig);
return err;
}
unsigned long long getnum(char *str, char **err)
{
char *e;
unsigned long long rv = strtoull(str, &e, 10);
if (e==str || *e) {
*err = str;
return 0;
}
return rv;
}
int main(int argc, char *argv[])
{
/* md_device start length */
int *fds = NULL;
char *buf = NULL;
char **disk_name = NULL;
unsigned long long *offsets = NULL;
int raid_disks = 0;
int active_disks;
int chunk_size = 0;
int layout = -1;
int level = 6;
enum repair repair = NO_REPAIR;
int failed_disk1 = -1;
int failed_disk2 = -1;
unsigned long long start, length;
int i;
int mdfd;
struct mdinfo *info = NULL, *comp = NULL;
char *err = NULL;
int exit_err = 0;
int close_flag = 0;
char *prg = strrchr(argv[0], '/');
if (prg == NULL)
prg = argv[0];
else
prg++;
if (argc < 4) {
fprintf(stderr, "Usage: %s md_device start_stripe length_stripes [autorepair]\n", prg);
fprintf(stderr, " or: %s md_device repair stripe failed_slot_1 failed_slot_2\n", prg);
exit_err = 1;
goto exitHere;
}
mdfd = open(argv[1], O_RDONLY);
if(mdfd < 0) {
perror(argv[1]);
fprintf(stderr, "%s: cannot open %s\n", prg, argv[1]);
exit_err = 2;
goto exitHere;
}
info = sysfs_read(mdfd, NULL,
GET_LEVEL|
GET_LAYOUT|
GET_DISKS|
GET_STATE |
GET_COMPONENT|
GET_CHUNK|
GET_DEVS|
GET_OFFSET|
GET_SIZE);
if(info == NULL) {
fprintf(stderr, "%s: Error reading sysfs information of %s\n", prg, argv[1]);
exit_err = 9;
goto exitHere;
}
if(info->array.level != level) {
fprintf(stderr, "%s: %s not a RAID-6\n", prg, argv[1]);
exit_err = 3;
goto exitHere;
}
if(info->array.failed_disks > 0) {
fprintf(stderr, "%s: %s degraded array\n", prg, argv[1]);
exit_err = 8;
goto exitHere;
}
printf("layout: %d\n", info->array.layout);
printf("disks: %d\n", info->array.raid_disks);
printf("component size: %llu\n", info->component_size * 512);
printf("total stripes: %llu\n", (info->component_size * 512) / info->array.chunk_size);
printf("chunk size: %d\n", info->array.chunk_size);
printf("\n");
comp = info->devs;
for(i = 0, active_disks = 0; active_disks < info->array.raid_disks; i++) {
printf("disk: %d - offset: %llu - size: %llu - name: %s - slot: %d\n",
i, comp->data_offset * 512, comp->component_size * 512,
map_dev(comp->disk.major, comp->disk.minor, 0),
comp->disk.raid_disk);
if(comp->disk.raid_disk >= 0)
active_disks++;
comp = comp->next;
}
printf("\n");
close(mdfd);
raid_disks = info->array.raid_disks;
chunk_size = info->array.chunk_size;
layout = info->array.layout;
if (strcmp(argv[2], "repair")==0) {
if (argc < 6) {
fprintf(stderr, "For repair mode, call %s md_device repair stripe failed_slot_1 failed_slot_2\n", prg);
exit_err = 1;
goto exitHere;
}
repair = MANUAL_REPAIR;
start = getnum(argv[3], &err);
length = 1;
failed_disk1 = getnum(argv[4], &err);
failed_disk2 = getnum(argv[5], &err);
if(failed_disk1 >= info->array.raid_disks) {
fprintf(stderr, "%s: failed_slot_1 index is higher than number of devices in raid\n", prg);
exit_err = 4;
goto exitHere;
}
if(failed_disk2 >= info->array.raid_disks) {
fprintf(stderr, "%s: failed_slot_2 index is higher than number of devices in raid\n", prg);
exit_err = 4;
goto exitHere;
}
if(failed_disk1 == failed_disk2) {
fprintf(stderr, "%s: failed_slot_1 and failed_slot_2 are the same\n", prg);
exit_err = 4;
goto exitHere;
}
}
else {
start = getnum(argv[2], &err);
length = getnum(argv[3], &err);
if (argc >= 5 && strcmp(argv[4], "autorepair")==0)
repair = AUTO_REPAIR;
}
if (err) {
fprintf(stderr, "%s: Bad number: %s\n", prg, err);
exit_err = 4;
goto exitHere;
}
if(start > ((info->component_size * 512) / chunk_size)) {
start = (info->component_size * 512) / chunk_size;
fprintf(stderr, "%s: start beyond disks size\n", prg);
}
if((length == 0) ||
((length + start) > ((info->component_size * 512) / chunk_size))) {
length = (info->component_size * 512) / chunk_size - start;
}
disk_name = xmalloc(raid_disks * sizeof(*disk_name));
fds = xmalloc(raid_disks * sizeof(*fds));
offsets = xcalloc(raid_disks, sizeof(*offsets));
buf = xmalloc(raid_disks * chunk_size);
for(i=0; i<raid_disks; i++) {
fds[i] = -1;
}
close_flag = 1;
comp = info->devs;
for (i=0, active_disks=0; active_disks<raid_disks; i++) {
int disk_slot = comp->disk.raid_disk;
if(disk_slot >= 0) {
disk_name[disk_slot] = map_dev(comp->disk.major, comp->disk.minor, 0);
offsets[disk_slot] = comp->data_offset * 512;
fds[disk_slot] = open(disk_name[disk_slot], O_RDWR | O_DIRECT);
if (fds[disk_slot] < 0) {
perror(disk_name[disk_slot]);
fprintf(stderr,"%s: cannot open %s\n", prg, disk_name[disk_slot]);
exit_err = 6;
goto exitHere;
}
active_disks++;
}
comp = comp->next;
}
int rv = check_stripes(info, fds, offsets,
raid_disks, chunk_size, level, layout,
start, length, disk_name, repair, failed_disk1, failed_disk2);
if (rv != 0) {
fprintf(stderr, "%s: check_stripes returned %d\n", prg, rv);
exit_err = 7;
goto exitHere;
}
exitHere:
if (close_flag)
for(i = 0; i < raid_disks; i++)
close(fds[i]);
free(disk_name);
free(fds);
free(offsets);
free(buf);
exit(exit_err);
}
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