1126 lines
32 KiB
C
1126 lines
32 KiB
C
/*
|
|
* Quorum Block filter
|
|
*
|
|
* Copyright (C) 2012-2014 Nodalink, EURL.
|
|
*
|
|
* Author:
|
|
* Benoît Canet <benoit.canet@irqsave.net>
|
|
*
|
|
* Based on the design and code of blkverify.c (Copyright (C) 2010 IBM, Corp)
|
|
* and blkmirror.c (Copyright (C) 2011 Red Hat, Inc).
|
|
*
|
|
* This work is licensed under the terms of the GNU GPL, version 2 or later.
|
|
* See the COPYING file in the top-level directory.
|
|
*/
|
|
|
|
#include "qemu/osdep.h"
|
|
#include "qemu/cutils.h"
|
|
#include "block/block_int.h"
|
|
#include "qapi/qmp/qbool.h"
|
|
#include "qapi/qmp/qdict.h"
|
|
#include "qapi/qmp/qerror.h"
|
|
#include "qapi/qmp/qint.h"
|
|
#include "qapi/qmp/qjson.h"
|
|
#include "qapi/qmp/qlist.h"
|
|
#include "qapi/qmp/qstring.h"
|
|
#include "qapi-event.h"
|
|
#include "crypto/hash.h"
|
|
|
|
#define HASH_LENGTH 32
|
|
|
|
#define QUORUM_OPT_VOTE_THRESHOLD "vote-threshold"
|
|
#define QUORUM_OPT_BLKVERIFY "blkverify"
|
|
#define QUORUM_OPT_REWRITE "rewrite-corrupted"
|
|
#define QUORUM_OPT_READ_PATTERN "read-pattern"
|
|
|
|
/* This union holds a vote hash value */
|
|
typedef union QuorumVoteValue {
|
|
uint8_t h[HASH_LENGTH]; /* SHA-256 hash */
|
|
int64_t l; /* simpler 64 bits hash */
|
|
} QuorumVoteValue;
|
|
|
|
/* A vote item */
|
|
typedef struct QuorumVoteItem {
|
|
int index;
|
|
QLIST_ENTRY(QuorumVoteItem) next;
|
|
} QuorumVoteItem;
|
|
|
|
/* this structure is a vote version. A version is the set of votes sharing the
|
|
* same vote value.
|
|
* The set of votes will be tracked with the items field and its cardinality is
|
|
* vote_count.
|
|
*/
|
|
typedef struct QuorumVoteVersion {
|
|
QuorumVoteValue value;
|
|
int index;
|
|
int vote_count;
|
|
QLIST_HEAD(, QuorumVoteItem) items;
|
|
QLIST_ENTRY(QuorumVoteVersion) next;
|
|
} QuorumVoteVersion;
|
|
|
|
/* this structure holds a group of vote versions together */
|
|
typedef struct QuorumVotes {
|
|
QLIST_HEAD(, QuorumVoteVersion) vote_list;
|
|
bool (*compare)(QuorumVoteValue *a, QuorumVoteValue *b);
|
|
} QuorumVotes;
|
|
|
|
/* the following structure holds the state of one quorum instance */
|
|
typedef struct BDRVQuorumState {
|
|
BdrvChild **children; /* children BlockDriverStates */
|
|
int num_children; /* children count */
|
|
unsigned next_child_index; /* the index of the next child that should
|
|
* be added
|
|
*/
|
|
int threshold; /* if less than threshold children reads gave the
|
|
* same result a quorum error occurs.
|
|
*/
|
|
bool is_blkverify; /* true if the driver is in blkverify mode
|
|
* Writes are mirrored on two children devices.
|
|
* On reads the two children devices' contents are
|
|
* compared and if a difference is spotted its
|
|
* location is printed and the code aborts.
|
|
* It is useful to debug other block drivers by
|
|
* comparing them with a reference one.
|
|
*/
|
|
bool rewrite_corrupted;/* true if the driver must rewrite-on-read corrupted
|
|
* block if Quorum is reached.
|
|
*/
|
|
|
|
QuorumReadPattern read_pattern;
|
|
} BDRVQuorumState;
|
|
|
|
typedef struct QuorumAIOCB QuorumAIOCB;
|
|
|
|
/* Quorum will create one instance of the following structure per operation it
|
|
* performs on its children.
|
|
* So for each read/write operation coming from the upper layer there will be
|
|
* $children_count QuorumChildRequest.
|
|
*/
|
|
typedef struct QuorumChildRequest {
|
|
BlockAIOCB *aiocb;
|
|
QEMUIOVector qiov;
|
|
uint8_t *buf;
|
|
int ret;
|
|
QuorumAIOCB *parent;
|
|
} QuorumChildRequest;
|
|
|
|
/* Quorum will use the following structure to track progress of each read/write
|
|
* operation received by the upper layer.
|
|
* This structure hold pointers to the QuorumChildRequest structures instances
|
|
* used to do operations on each children and track overall progress.
|
|
*/
|
|
struct QuorumAIOCB {
|
|
BlockAIOCB common;
|
|
|
|
/* Request metadata */
|
|
uint64_t sector_num;
|
|
int nb_sectors;
|
|
|
|
QEMUIOVector *qiov; /* calling IOV */
|
|
|
|
QuorumChildRequest *qcrs; /* individual child requests */
|
|
int count; /* number of completed AIOCB */
|
|
int success_count; /* number of successfully completed AIOCB */
|
|
|
|
int rewrite_count; /* number of replica to rewrite: count down to
|
|
* zero once writes are fired
|
|
*/
|
|
|
|
QuorumVotes votes;
|
|
|
|
bool is_read;
|
|
int vote_ret;
|
|
int child_iter; /* which child to read in fifo pattern */
|
|
};
|
|
|
|
static bool quorum_vote(QuorumAIOCB *acb);
|
|
|
|
static void quorum_aio_cancel(BlockAIOCB *blockacb)
|
|
{
|
|
QuorumAIOCB *acb = container_of(blockacb, QuorumAIOCB, common);
|
|
BDRVQuorumState *s = acb->common.bs->opaque;
|
|
int i;
|
|
|
|
/* cancel all callbacks */
|
|
for (i = 0; i < s->num_children; i++) {
|
|
if (acb->qcrs[i].aiocb) {
|
|
bdrv_aio_cancel_async(acb->qcrs[i].aiocb);
|
|
}
|
|
}
|
|
}
|
|
|
|
static AIOCBInfo quorum_aiocb_info = {
|
|
.aiocb_size = sizeof(QuorumAIOCB),
|
|
.cancel_async = quorum_aio_cancel,
|
|
};
|
|
|
|
static void quorum_aio_finalize(QuorumAIOCB *acb)
|
|
{
|
|
int i, ret = 0;
|
|
|
|
if (acb->vote_ret) {
|
|
ret = acb->vote_ret;
|
|
}
|
|
|
|
acb->common.cb(acb->common.opaque, ret);
|
|
|
|
if (acb->is_read) {
|
|
/* on the quorum case acb->child_iter == s->num_children - 1 */
|
|
for (i = 0; i <= acb->child_iter; i++) {
|
|
qemu_vfree(acb->qcrs[i].buf);
|
|
qemu_iovec_destroy(&acb->qcrs[i].qiov);
|
|
}
|
|
}
|
|
|
|
g_free(acb->qcrs);
|
|
qemu_aio_unref(acb);
|
|
}
|
|
|
|
static bool quorum_sha256_compare(QuorumVoteValue *a, QuorumVoteValue *b)
|
|
{
|
|
return !memcmp(a->h, b->h, HASH_LENGTH);
|
|
}
|
|
|
|
static bool quorum_64bits_compare(QuorumVoteValue *a, QuorumVoteValue *b)
|
|
{
|
|
return a->l == b->l;
|
|
}
|
|
|
|
static QuorumAIOCB *quorum_aio_get(BDRVQuorumState *s,
|
|
BlockDriverState *bs,
|
|
QEMUIOVector *qiov,
|
|
uint64_t sector_num,
|
|
int nb_sectors,
|
|
BlockCompletionFunc *cb,
|
|
void *opaque)
|
|
{
|
|
QuorumAIOCB *acb = qemu_aio_get(&quorum_aiocb_info, bs, cb, opaque);
|
|
int i;
|
|
|
|
acb->common.bs->opaque = s;
|
|
acb->sector_num = sector_num;
|
|
acb->nb_sectors = nb_sectors;
|
|
acb->qiov = qiov;
|
|
acb->qcrs = g_new0(QuorumChildRequest, s->num_children);
|
|
acb->count = 0;
|
|
acb->success_count = 0;
|
|
acb->rewrite_count = 0;
|
|
acb->votes.compare = quorum_sha256_compare;
|
|
QLIST_INIT(&acb->votes.vote_list);
|
|
acb->is_read = false;
|
|
acb->vote_ret = 0;
|
|
|
|
for (i = 0; i < s->num_children; i++) {
|
|
acb->qcrs[i].buf = NULL;
|
|
acb->qcrs[i].ret = 0;
|
|
acb->qcrs[i].parent = acb;
|
|
}
|
|
|
|
return acb;
|
|
}
|
|
|
|
static void quorum_report_bad(QuorumOpType type, uint64_t sector_num,
|
|
int nb_sectors, char *node_name, int ret)
|
|
{
|
|
const char *msg = NULL;
|
|
if (ret < 0) {
|
|
msg = strerror(-ret);
|
|
}
|
|
|
|
qapi_event_send_quorum_report_bad(type, !!msg, msg, node_name,
|
|
sector_num, nb_sectors, &error_abort);
|
|
}
|
|
|
|
static void quorum_report_failure(QuorumAIOCB *acb)
|
|
{
|
|
const char *reference = bdrv_get_device_or_node_name(acb->common.bs);
|
|
qapi_event_send_quorum_failure(reference, acb->sector_num,
|
|
acb->nb_sectors, &error_abort);
|
|
}
|
|
|
|
static int quorum_vote_error(QuorumAIOCB *acb);
|
|
|
|
static bool quorum_has_too_much_io_failed(QuorumAIOCB *acb)
|
|
{
|
|
BDRVQuorumState *s = acb->common.bs->opaque;
|
|
|
|
if (acb->success_count < s->threshold) {
|
|
acb->vote_ret = quorum_vote_error(acb);
|
|
quorum_report_failure(acb);
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
static void quorum_rewrite_aio_cb(void *opaque, int ret)
|
|
{
|
|
QuorumAIOCB *acb = opaque;
|
|
|
|
/* one less rewrite to do */
|
|
acb->rewrite_count--;
|
|
|
|
/* wait until all rewrite callbacks have completed */
|
|
if (acb->rewrite_count) {
|
|
return;
|
|
}
|
|
|
|
quorum_aio_finalize(acb);
|
|
}
|
|
|
|
static BlockAIOCB *read_fifo_child(QuorumAIOCB *acb);
|
|
|
|
static void quorum_copy_qiov(QEMUIOVector *dest, QEMUIOVector *source)
|
|
{
|
|
int i;
|
|
assert(dest->niov == source->niov);
|
|
assert(dest->size == source->size);
|
|
for (i = 0; i < source->niov; i++) {
|
|
assert(dest->iov[i].iov_len == source->iov[i].iov_len);
|
|
memcpy(dest->iov[i].iov_base,
|
|
source->iov[i].iov_base,
|
|
source->iov[i].iov_len);
|
|
}
|
|
}
|
|
|
|
static void quorum_aio_cb(void *opaque, int ret)
|
|
{
|
|
QuorumChildRequest *sacb = opaque;
|
|
QuorumAIOCB *acb = sacb->parent;
|
|
BDRVQuorumState *s = acb->common.bs->opaque;
|
|
bool rewrite = false;
|
|
|
|
if (ret == 0) {
|
|
acb->success_count++;
|
|
} else {
|
|
QuorumOpType type;
|
|
type = acb->is_read ? QUORUM_OP_TYPE_READ : QUORUM_OP_TYPE_WRITE;
|
|
quorum_report_bad(type, acb->sector_num, acb->nb_sectors,
|
|
sacb->aiocb->bs->node_name, ret);
|
|
}
|
|
|
|
if (acb->is_read && s->read_pattern == QUORUM_READ_PATTERN_FIFO) {
|
|
/* We try to read next child in FIFO order if we fail to read */
|
|
if (ret < 0 && (acb->child_iter + 1) < s->num_children) {
|
|
acb->child_iter++;
|
|
read_fifo_child(acb);
|
|
return;
|
|
}
|
|
|
|
if (ret == 0) {
|
|
quorum_copy_qiov(acb->qiov, &acb->qcrs[acb->child_iter].qiov);
|
|
}
|
|
acb->vote_ret = ret;
|
|
quorum_aio_finalize(acb);
|
|
return;
|
|
}
|
|
|
|
sacb->ret = ret;
|
|
acb->count++;
|
|
assert(acb->count <= s->num_children);
|
|
assert(acb->success_count <= s->num_children);
|
|
if (acb->count < s->num_children) {
|
|
return;
|
|
}
|
|
|
|
/* Do the vote on read */
|
|
if (acb->is_read) {
|
|
rewrite = quorum_vote(acb);
|
|
} else {
|
|
quorum_has_too_much_io_failed(acb);
|
|
}
|
|
|
|
/* if no rewrite is done the code will finish right away */
|
|
if (!rewrite) {
|
|
quorum_aio_finalize(acb);
|
|
}
|
|
}
|
|
|
|
static void quorum_report_bad_versions(BDRVQuorumState *s,
|
|
QuorumAIOCB *acb,
|
|
QuorumVoteValue *value)
|
|
{
|
|
QuorumVoteVersion *version;
|
|
QuorumVoteItem *item;
|
|
|
|
QLIST_FOREACH(version, &acb->votes.vote_list, next) {
|
|
if (acb->votes.compare(&version->value, value)) {
|
|
continue;
|
|
}
|
|
QLIST_FOREACH(item, &version->items, next) {
|
|
quorum_report_bad(QUORUM_OP_TYPE_READ, acb->sector_num,
|
|
acb->nb_sectors,
|
|
s->children[item->index]->bs->node_name, 0);
|
|
}
|
|
}
|
|
}
|
|
|
|
static bool quorum_rewrite_bad_versions(BDRVQuorumState *s, QuorumAIOCB *acb,
|
|
QuorumVoteValue *value)
|
|
{
|
|
QuorumVoteVersion *version;
|
|
QuorumVoteItem *item;
|
|
int count = 0;
|
|
|
|
/* first count the number of bad versions: done first to avoid concurrency
|
|
* issues.
|
|
*/
|
|
QLIST_FOREACH(version, &acb->votes.vote_list, next) {
|
|
if (acb->votes.compare(&version->value, value)) {
|
|
continue;
|
|
}
|
|
QLIST_FOREACH(item, &version->items, next) {
|
|
count++;
|
|
}
|
|
}
|
|
|
|
/* quorum_rewrite_aio_cb will count down this to zero */
|
|
acb->rewrite_count = count;
|
|
|
|
/* now fire the correcting rewrites */
|
|
QLIST_FOREACH(version, &acb->votes.vote_list, next) {
|
|
if (acb->votes.compare(&version->value, value)) {
|
|
continue;
|
|
}
|
|
QLIST_FOREACH(item, &version->items, next) {
|
|
bdrv_aio_writev(s->children[item->index]->bs, acb->sector_num,
|
|
acb->qiov, acb->nb_sectors, quorum_rewrite_aio_cb,
|
|
acb);
|
|
}
|
|
}
|
|
|
|
/* return true if any rewrite is done else false */
|
|
return count;
|
|
}
|
|
|
|
static void quorum_count_vote(QuorumVotes *votes,
|
|
QuorumVoteValue *value,
|
|
int index)
|
|
{
|
|
QuorumVoteVersion *v = NULL, *version = NULL;
|
|
QuorumVoteItem *item;
|
|
|
|
/* look if we have something with this hash */
|
|
QLIST_FOREACH(v, &votes->vote_list, next) {
|
|
if (votes->compare(&v->value, value)) {
|
|
version = v;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* It's a version not yet in the list add it */
|
|
if (!version) {
|
|
version = g_new0(QuorumVoteVersion, 1);
|
|
QLIST_INIT(&version->items);
|
|
memcpy(&version->value, value, sizeof(version->value));
|
|
version->index = index;
|
|
version->vote_count = 0;
|
|
QLIST_INSERT_HEAD(&votes->vote_list, version, next);
|
|
}
|
|
|
|
version->vote_count++;
|
|
|
|
item = g_new0(QuorumVoteItem, 1);
|
|
item->index = index;
|
|
QLIST_INSERT_HEAD(&version->items, item, next);
|
|
}
|
|
|
|
static void quorum_free_vote_list(QuorumVotes *votes)
|
|
{
|
|
QuorumVoteVersion *version, *next_version;
|
|
QuorumVoteItem *item, *next_item;
|
|
|
|
QLIST_FOREACH_SAFE(version, &votes->vote_list, next, next_version) {
|
|
QLIST_REMOVE(version, next);
|
|
QLIST_FOREACH_SAFE(item, &version->items, next, next_item) {
|
|
QLIST_REMOVE(item, next);
|
|
g_free(item);
|
|
}
|
|
g_free(version);
|
|
}
|
|
}
|
|
|
|
static int quorum_compute_hash(QuorumAIOCB *acb, int i, QuorumVoteValue *hash)
|
|
{
|
|
QEMUIOVector *qiov = &acb->qcrs[i].qiov;
|
|
size_t len = sizeof(hash->h);
|
|
uint8_t *data = hash->h;
|
|
|
|
/* XXX - would be nice if we could pass in the Error **
|
|
* and propagate that back, but this quorum code is
|
|
* restricted to just errno values currently */
|
|
if (qcrypto_hash_bytesv(QCRYPTO_HASH_ALG_SHA256,
|
|
qiov->iov, qiov->niov,
|
|
&data, &len,
|
|
NULL) < 0) {
|
|
return -EINVAL;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static QuorumVoteVersion *quorum_get_vote_winner(QuorumVotes *votes)
|
|
{
|
|
int max = 0;
|
|
QuorumVoteVersion *candidate, *winner = NULL;
|
|
|
|
QLIST_FOREACH(candidate, &votes->vote_list, next) {
|
|
if (candidate->vote_count > max) {
|
|
max = candidate->vote_count;
|
|
winner = candidate;
|
|
}
|
|
}
|
|
|
|
return winner;
|
|
}
|
|
|
|
/* qemu_iovec_compare is handy for blkverify mode because it returns the first
|
|
* differing byte location. Yet it is handcoded to compare vectors one byte
|
|
* after another so it does not benefit from the libc SIMD optimizations.
|
|
* quorum_iovec_compare is written for speed and should be used in the non
|
|
* blkverify mode of quorum.
|
|
*/
|
|
static bool quorum_iovec_compare(QEMUIOVector *a, QEMUIOVector *b)
|
|
{
|
|
int i;
|
|
int result;
|
|
|
|
assert(a->niov == b->niov);
|
|
for (i = 0; i < a->niov; i++) {
|
|
assert(a->iov[i].iov_len == b->iov[i].iov_len);
|
|
result = memcmp(a->iov[i].iov_base,
|
|
b->iov[i].iov_base,
|
|
a->iov[i].iov_len);
|
|
if (result) {
|
|
return false;
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
static void GCC_FMT_ATTR(2, 3) quorum_err(QuorumAIOCB *acb,
|
|
const char *fmt, ...)
|
|
{
|
|
va_list ap;
|
|
|
|
va_start(ap, fmt);
|
|
fprintf(stderr, "quorum: sector_num=%" PRId64 " nb_sectors=%d ",
|
|
acb->sector_num, acb->nb_sectors);
|
|
vfprintf(stderr, fmt, ap);
|
|
fprintf(stderr, "\n");
|
|
va_end(ap);
|
|
exit(1);
|
|
}
|
|
|
|
static bool quorum_compare(QuorumAIOCB *acb,
|
|
QEMUIOVector *a,
|
|
QEMUIOVector *b)
|
|
{
|
|
BDRVQuorumState *s = acb->common.bs->opaque;
|
|
ssize_t offset;
|
|
|
|
/* This driver will replace blkverify in this particular case */
|
|
if (s->is_blkverify) {
|
|
offset = qemu_iovec_compare(a, b);
|
|
if (offset != -1) {
|
|
quorum_err(acb, "contents mismatch in sector %" PRId64,
|
|
acb->sector_num +
|
|
(uint64_t)(offset / BDRV_SECTOR_SIZE));
|
|
}
|
|
return true;
|
|
}
|
|
|
|
return quorum_iovec_compare(a, b);
|
|
}
|
|
|
|
/* Do a vote to get the error code */
|
|
static int quorum_vote_error(QuorumAIOCB *acb)
|
|
{
|
|
BDRVQuorumState *s = acb->common.bs->opaque;
|
|
QuorumVoteVersion *winner = NULL;
|
|
QuorumVotes error_votes;
|
|
QuorumVoteValue result_value;
|
|
int i, ret = 0;
|
|
bool error = false;
|
|
|
|
QLIST_INIT(&error_votes.vote_list);
|
|
error_votes.compare = quorum_64bits_compare;
|
|
|
|
for (i = 0; i < s->num_children; i++) {
|
|
ret = acb->qcrs[i].ret;
|
|
if (ret) {
|
|
error = true;
|
|
result_value.l = ret;
|
|
quorum_count_vote(&error_votes, &result_value, i);
|
|
}
|
|
}
|
|
|
|
if (error) {
|
|
winner = quorum_get_vote_winner(&error_votes);
|
|
ret = winner->value.l;
|
|
}
|
|
|
|
quorum_free_vote_list(&error_votes);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static bool quorum_vote(QuorumAIOCB *acb)
|
|
{
|
|
bool quorum = true;
|
|
bool rewrite = false;
|
|
int i, j, ret;
|
|
QuorumVoteValue hash;
|
|
BDRVQuorumState *s = acb->common.bs->opaque;
|
|
QuorumVoteVersion *winner;
|
|
|
|
if (quorum_has_too_much_io_failed(acb)) {
|
|
return false;
|
|
}
|
|
|
|
/* get the index of the first successful read */
|
|
for (i = 0; i < s->num_children; i++) {
|
|
if (!acb->qcrs[i].ret) {
|
|
break;
|
|
}
|
|
}
|
|
|
|
assert(i < s->num_children);
|
|
|
|
/* compare this read with all other successful reads stopping at quorum
|
|
* failure
|
|
*/
|
|
for (j = i + 1; j < s->num_children; j++) {
|
|
if (acb->qcrs[j].ret) {
|
|
continue;
|
|
}
|
|
quorum = quorum_compare(acb, &acb->qcrs[i].qiov, &acb->qcrs[j].qiov);
|
|
if (!quorum) {
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* Every successful read agrees */
|
|
if (quorum) {
|
|
quorum_copy_qiov(acb->qiov, &acb->qcrs[i].qiov);
|
|
return false;
|
|
}
|
|
|
|
/* compute hashes for each successful read, also store indexes */
|
|
for (i = 0; i < s->num_children; i++) {
|
|
if (acb->qcrs[i].ret) {
|
|
continue;
|
|
}
|
|
ret = quorum_compute_hash(acb, i, &hash);
|
|
/* if ever the hash computation failed */
|
|
if (ret < 0) {
|
|
acb->vote_ret = ret;
|
|
goto free_exit;
|
|
}
|
|
quorum_count_vote(&acb->votes, &hash, i);
|
|
}
|
|
|
|
/* vote to select the most represented version */
|
|
winner = quorum_get_vote_winner(&acb->votes);
|
|
|
|
/* if the winner count is smaller than threshold the read fails */
|
|
if (winner->vote_count < s->threshold) {
|
|
quorum_report_failure(acb);
|
|
acb->vote_ret = -EIO;
|
|
goto free_exit;
|
|
}
|
|
|
|
/* we have a winner: copy it */
|
|
quorum_copy_qiov(acb->qiov, &acb->qcrs[winner->index].qiov);
|
|
|
|
/* some versions are bad print them */
|
|
quorum_report_bad_versions(s, acb, &winner->value);
|
|
|
|
/* corruption correction is enabled */
|
|
if (s->rewrite_corrupted) {
|
|
rewrite = quorum_rewrite_bad_versions(s, acb, &winner->value);
|
|
}
|
|
|
|
free_exit:
|
|
/* free lists */
|
|
quorum_free_vote_list(&acb->votes);
|
|
return rewrite;
|
|
}
|
|
|
|
static BlockAIOCB *read_quorum_children(QuorumAIOCB *acb)
|
|
{
|
|
BDRVQuorumState *s = acb->common.bs->opaque;
|
|
int i;
|
|
|
|
for (i = 0; i < s->num_children; i++) {
|
|
acb->qcrs[i].buf = qemu_blockalign(s->children[i]->bs, acb->qiov->size);
|
|
qemu_iovec_init(&acb->qcrs[i].qiov, acb->qiov->niov);
|
|
qemu_iovec_clone(&acb->qcrs[i].qiov, acb->qiov, acb->qcrs[i].buf);
|
|
}
|
|
|
|
for (i = 0; i < s->num_children; i++) {
|
|
acb->qcrs[i].aiocb = bdrv_aio_readv(s->children[i]->bs, acb->sector_num,
|
|
&acb->qcrs[i].qiov, acb->nb_sectors,
|
|
quorum_aio_cb, &acb->qcrs[i]);
|
|
}
|
|
|
|
return &acb->common;
|
|
}
|
|
|
|
static BlockAIOCB *read_fifo_child(QuorumAIOCB *acb)
|
|
{
|
|
BDRVQuorumState *s = acb->common.bs->opaque;
|
|
|
|
acb->qcrs[acb->child_iter].buf =
|
|
qemu_blockalign(s->children[acb->child_iter]->bs, acb->qiov->size);
|
|
qemu_iovec_init(&acb->qcrs[acb->child_iter].qiov, acb->qiov->niov);
|
|
qemu_iovec_clone(&acb->qcrs[acb->child_iter].qiov, acb->qiov,
|
|
acb->qcrs[acb->child_iter].buf);
|
|
acb->qcrs[acb->child_iter].aiocb =
|
|
bdrv_aio_readv(s->children[acb->child_iter]->bs, acb->sector_num,
|
|
&acb->qcrs[acb->child_iter].qiov, acb->nb_sectors,
|
|
quorum_aio_cb, &acb->qcrs[acb->child_iter]);
|
|
|
|
return &acb->common;
|
|
}
|
|
|
|
static BlockAIOCB *quorum_aio_readv(BlockDriverState *bs,
|
|
int64_t sector_num,
|
|
QEMUIOVector *qiov,
|
|
int nb_sectors,
|
|
BlockCompletionFunc *cb,
|
|
void *opaque)
|
|
{
|
|
BDRVQuorumState *s = bs->opaque;
|
|
QuorumAIOCB *acb = quorum_aio_get(s, bs, qiov, sector_num,
|
|
nb_sectors, cb, opaque);
|
|
acb->is_read = true;
|
|
|
|
if (s->read_pattern == QUORUM_READ_PATTERN_QUORUM) {
|
|
acb->child_iter = s->num_children - 1;
|
|
return read_quorum_children(acb);
|
|
}
|
|
|
|
acb->child_iter = 0;
|
|
return read_fifo_child(acb);
|
|
}
|
|
|
|
static BlockAIOCB *quorum_aio_writev(BlockDriverState *bs,
|
|
int64_t sector_num,
|
|
QEMUIOVector *qiov,
|
|
int nb_sectors,
|
|
BlockCompletionFunc *cb,
|
|
void *opaque)
|
|
{
|
|
BDRVQuorumState *s = bs->opaque;
|
|
QuorumAIOCB *acb = quorum_aio_get(s, bs, qiov, sector_num, nb_sectors,
|
|
cb, opaque);
|
|
int i;
|
|
|
|
for (i = 0; i < s->num_children; i++) {
|
|
acb->qcrs[i].aiocb = bdrv_aio_writev(s->children[i]->bs, sector_num,
|
|
qiov, nb_sectors, &quorum_aio_cb,
|
|
&acb->qcrs[i]);
|
|
}
|
|
|
|
return &acb->common;
|
|
}
|
|
|
|
static int64_t quorum_getlength(BlockDriverState *bs)
|
|
{
|
|
BDRVQuorumState *s = bs->opaque;
|
|
int64_t result;
|
|
int i;
|
|
|
|
/* check that all file have the same length */
|
|
result = bdrv_getlength(s->children[0]->bs);
|
|
if (result < 0) {
|
|
return result;
|
|
}
|
|
for (i = 1; i < s->num_children; i++) {
|
|
int64_t value = bdrv_getlength(s->children[i]->bs);
|
|
if (value < 0) {
|
|
return value;
|
|
}
|
|
if (value != result) {
|
|
return -EIO;
|
|
}
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
static coroutine_fn int quorum_co_flush(BlockDriverState *bs)
|
|
{
|
|
BDRVQuorumState *s = bs->opaque;
|
|
QuorumVoteVersion *winner = NULL;
|
|
QuorumVotes error_votes;
|
|
QuorumVoteValue result_value;
|
|
int i;
|
|
int result = 0;
|
|
int success_count = 0;
|
|
|
|
QLIST_INIT(&error_votes.vote_list);
|
|
error_votes.compare = quorum_64bits_compare;
|
|
|
|
for (i = 0; i < s->num_children; i++) {
|
|
result = bdrv_co_flush(s->children[i]->bs);
|
|
if (result) {
|
|
quorum_report_bad(QUORUM_OP_TYPE_FLUSH, 0,
|
|
bdrv_nb_sectors(s->children[i]->bs),
|
|
s->children[i]->bs->node_name, result);
|
|
result_value.l = result;
|
|
quorum_count_vote(&error_votes, &result_value, i);
|
|
} else {
|
|
success_count++;
|
|
}
|
|
}
|
|
|
|
if (success_count >= s->threshold) {
|
|
result = 0;
|
|
} else {
|
|
winner = quorum_get_vote_winner(&error_votes);
|
|
result = winner->value.l;
|
|
}
|
|
quorum_free_vote_list(&error_votes);
|
|
|
|
return result;
|
|
}
|
|
|
|
static bool quorum_recurse_is_first_non_filter(BlockDriverState *bs,
|
|
BlockDriverState *candidate)
|
|
{
|
|
BDRVQuorumState *s = bs->opaque;
|
|
int i;
|
|
|
|
for (i = 0; i < s->num_children; i++) {
|
|
bool perm = bdrv_recurse_is_first_non_filter(s->children[i]->bs,
|
|
candidate);
|
|
if (perm) {
|
|
return true;
|
|
}
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
static int quorum_valid_threshold(int threshold, int num_children, Error **errp)
|
|
{
|
|
|
|
if (threshold < 1) {
|
|
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
|
|
"vote-threshold", "value >= 1");
|
|
return -ERANGE;
|
|
}
|
|
|
|
if (threshold > num_children) {
|
|
error_setg(errp, "threshold may not exceed children count");
|
|
return -ERANGE;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static QemuOptsList quorum_runtime_opts = {
|
|
.name = "quorum",
|
|
.head = QTAILQ_HEAD_INITIALIZER(quorum_runtime_opts.head),
|
|
.desc = {
|
|
{
|
|
.name = QUORUM_OPT_VOTE_THRESHOLD,
|
|
.type = QEMU_OPT_NUMBER,
|
|
.help = "The number of vote needed for reaching quorum",
|
|
},
|
|
{
|
|
.name = QUORUM_OPT_BLKVERIFY,
|
|
.type = QEMU_OPT_BOOL,
|
|
.help = "Trigger block verify mode if set",
|
|
},
|
|
{
|
|
.name = QUORUM_OPT_REWRITE,
|
|
.type = QEMU_OPT_BOOL,
|
|
.help = "Rewrite corrupted block on read quorum",
|
|
},
|
|
{
|
|
.name = QUORUM_OPT_READ_PATTERN,
|
|
.type = QEMU_OPT_STRING,
|
|
.help = "Allowed pattern: quorum, fifo. Quorum is default",
|
|
},
|
|
{ /* end of list */ }
|
|
},
|
|
};
|
|
|
|
static int parse_read_pattern(const char *opt)
|
|
{
|
|
int i;
|
|
|
|
if (!opt) {
|
|
/* Set quorum as default */
|
|
return QUORUM_READ_PATTERN_QUORUM;
|
|
}
|
|
|
|
for (i = 0; i < QUORUM_READ_PATTERN__MAX; i++) {
|
|
if (!strcmp(opt, QuorumReadPattern_lookup[i])) {
|
|
return i;
|
|
}
|
|
}
|
|
|
|
return -EINVAL;
|
|
}
|
|
|
|
static int quorum_open(BlockDriverState *bs, QDict *options, int flags,
|
|
Error **errp)
|
|
{
|
|
BDRVQuorumState *s = bs->opaque;
|
|
Error *local_err = NULL;
|
|
QemuOpts *opts = NULL;
|
|
bool *opened;
|
|
int i;
|
|
int ret = 0;
|
|
|
|
qdict_flatten(options);
|
|
|
|
/* count how many different children are present */
|
|
s->num_children = qdict_array_entries(options, "children.");
|
|
if (s->num_children < 0) {
|
|
error_setg(&local_err, "Option children is not a valid array");
|
|
ret = -EINVAL;
|
|
goto exit;
|
|
}
|
|
if (s->num_children < 1) {
|
|
error_setg(&local_err,
|
|
"Number of provided children must be 1 or more");
|
|
ret = -EINVAL;
|
|
goto exit;
|
|
}
|
|
|
|
opts = qemu_opts_create(&quorum_runtime_opts, NULL, 0, &error_abort);
|
|
qemu_opts_absorb_qdict(opts, options, &local_err);
|
|
if (local_err) {
|
|
ret = -EINVAL;
|
|
goto exit;
|
|
}
|
|
|
|
s->threshold = qemu_opt_get_number(opts, QUORUM_OPT_VOTE_THRESHOLD, 0);
|
|
/* and validate it against s->num_children */
|
|
ret = quorum_valid_threshold(s->threshold, s->num_children, &local_err);
|
|
if (ret < 0) {
|
|
goto exit;
|
|
}
|
|
|
|
ret = parse_read_pattern(qemu_opt_get(opts, QUORUM_OPT_READ_PATTERN));
|
|
if (ret < 0) {
|
|
error_setg(&local_err, "Please set read-pattern as fifo or quorum");
|
|
goto exit;
|
|
}
|
|
s->read_pattern = ret;
|
|
|
|
if (s->read_pattern == QUORUM_READ_PATTERN_QUORUM) {
|
|
/* is the driver in blkverify mode */
|
|
if (qemu_opt_get_bool(opts, QUORUM_OPT_BLKVERIFY, false) &&
|
|
s->num_children == 2 && s->threshold == 2) {
|
|
s->is_blkverify = true;
|
|
} else if (qemu_opt_get_bool(opts, QUORUM_OPT_BLKVERIFY, false)) {
|
|
fprintf(stderr, "blkverify mode is set by setting blkverify=on "
|
|
"and using two files with vote_threshold=2\n");
|
|
}
|
|
|
|
s->rewrite_corrupted = qemu_opt_get_bool(opts, QUORUM_OPT_REWRITE,
|
|
false);
|
|
if (s->rewrite_corrupted && s->is_blkverify) {
|
|
error_setg(&local_err,
|
|
"rewrite-corrupted=on cannot be used with blkverify=on");
|
|
ret = -EINVAL;
|
|
goto exit;
|
|
}
|
|
}
|
|
|
|
/* allocate the children array */
|
|
s->children = g_new0(BdrvChild *, s->num_children);
|
|
opened = g_new0(bool, s->num_children);
|
|
|
|
for (i = 0; i < s->num_children; i++) {
|
|
char indexstr[32];
|
|
ret = snprintf(indexstr, 32, "children.%d", i);
|
|
assert(ret < 32);
|
|
|
|
s->children[i] = bdrv_open_child(NULL, options, indexstr, bs,
|
|
&child_format, false, &local_err);
|
|
if (local_err) {
|
|
ret = -EINVAL;
|
|
goto close_exit;
|
|
}
|
|
|
|
opened[i] = true;
|
|
}
|
|
s->next_child_index = s->num_children;
|
|
|
|
g_free(opened);
|
|
goto exit;
|
|
|
|
close_exit:
|
|
/* cleanup on error */
|
|
for (i = 0; i < s->num_children; i++) {
|
|
if (!opened[i]) {
|
|
continue;
|
|
}
|
|
bdrv_unref_child(bs, s->children[i]);
|
|
}
|
|
g_free(s->children);
|
|
g_free(opened);
|
|
exit:
|
|
qemu_opts_del(opts);
|
|
/* propagate error */
|
|
if (local_err) {
|
|
error_propagate(errp, local_err);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static void quorum_close(BlockDriverState *bs)
|
|
{
|
|
BDRVQuorumState *s = bs->opaque;
|
|
int i;
|
|
|
|
for (i = 0; i < s->num_children; i++) {
|
|
bdrv_unref_child(bs, s->children[i]);
|
|
}
|
|
|
|
g_free(s->children);
|
|
}
|
|
|
|
static void quorum_add_child(BlockDriverState *bs, BlockDriverState *child_bs,
|
|
Error **errp)
|
|
{
|
|
BDRVQuorumState *s = bs->opaque;
|
|
BdrvChild *child;
|
|
char indexstr[32];
|
|
int ret;
|
|
|
|
assert(s->num_children <= INT_MAX / sizeof(BdrvChild *));
|
|
if (s->num_children == INT_MAX / sizeof(BdrvChild *) ||
|
|
s->next_child_index == UINT_MAX) {
|
|
error_setg(errp, "Too many children");
|
|
return;
|
|
}
|
|
|
|
ret = snprintf(indexstr, 32, "children.%u", s->next_child_index);
|
|
if (ret < 0 || ret >= 32) {
|
|
error_setg(errp, "cannot generate child name");
|
|
return;
|
|
}
|
|
s->next_child_index++;
|
|
|
|
bdrv_drained_begin(bs);
|
|
|
|
/* We can safely add the child now */
|
|
bdrv_ref(child_bs);
|
|
child = bdrv_attach_child(bs, child_bs, indexstr, &child_format);
|
|
s->children = g_renew(BdrvChild *, s->children, s->num_children + 1);
|
|
s->children[s->num_children++] = child;
|
|
|
|
bdrv_drained_end(bs);
|
|
}
|
|
|
|
static void quorum_del_child(BlockDriverState *bs, BdrvChild *child,
|
|
Error **errp)
|
|
{
|
|
BDRVQuorumState *s = bs->opaque;
|
|
int i;
|
|
|
|
for (i = 0; i < s->num_children; i++) {
|
|
if (s->children[i] == child) {
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* we have checked it in bdrv_del_child() */
|
|
assert(i < s->num_children);
|
|
|
|
if (s->num_children <= s->threshold) {
|
|
error_setg(errp,
|
|
"The number of children cannot be lower than the vote threshold %d",
|
|
s->threshold);
|
|
return;
|
|
}
|
|
|
|
bdrv_drained_begin(bs);
|
|
|
|
/* We can safely remove this child now */
|
|
memmove(&s->children[i], &s->children[i + 1],
|
|
(s->num_children - i - 1) * sizeof(BdrvChild *));
|
|
s->children = g_renew(BdrvChild *, s->children, --s->num_children);
|
|
bdrv_unref_child(bs, child);
|
|
|
|
bdrv_drained_end(bs);
|
|
}
|
|
|
|
static void quorum_refresh_filename(BlockDriverState *bs, QDict *options)
|
|
{
|
|
BDRVQuorumState *s = bs->opaque;
|
|
QDict *opts;
|
|
QList *children;
|
|
int i;
|
|
|
|
for (i = 0; i < s->num_children; i++) {
|
|
bdrv_refresh_filename(s->children[i]->bs);
|
|
if (!s->children[i]->bs->full_open_options) {
|
|
return;
|
|
}
|
|
}
|
|
|
|
children = qlist_new();
|
|
for (i = 0; i < s->num_children; i++) {
|
|
QINCREF(s->children[i]->bs->full_open_options);
|
|
qlist_append_obj(children,
|
|
QOBJECT(s->children[i]->bs->full_open_options));
|
|
}
|
|
|
|
opts = qdict_new();
|
|
qdict_put_obj(opts, "driver", QOBJECT(qstring_from_str("quorum")));
|
|
qdict_put_obj(opts, QUORUM_OPT_VOTE_THRESHOLD,
|
|
QOBJECT(qint_from_int(s->threshold)));
|
|
qdict_put_obj(opts, QUORUM_OPT_BLKVERIFY,
|
|
QOBJECT(qbool_from_bool(s->is_blkverify)));
|
|
qdict_put_obj(opts, QUORUM_OPT_REWRITE,
|
|
QOBJECT(qbool_from_bool(s->rewrite_corrupted)));
|
|
qdict_put_obj(opts, "children", QOBJECT(children));
|
|
|
|
bs->full_open_options = opts;
|
|
}
|
|
|
|
static BlockDriver bdrv_quorum = {
|
|
.format_name = "quorum",
|
|
.protocol_name = "quorum",
|
|
|
|
.instance_size = sizeof(BDRVQuorumState),
|
|
|
|
.bdrv_file_open = quorum_open,
|
|
.bdrv_close = quorum_close,
|
|
.bdrv_refresh_filename = quorum_refresh_filename,
|
|
|
|
.bdrv_co_flush_to_disk = quorum_co_flush,
|
|
|
|
.bdrv_getlength = quorum_getlength,
|
|
|
|
.bdrv_aio_readv = quorum_aio_readv,
|
|
.bdrv_aio_writev = quorum_aio_writev,
|
|
|
|
.bdrv_add_child = quorum_add_child,
|
|
.bdrv_del_child = quorum_del_child,
|
|
|
|
.is_filter = true,
|
|
.bdrv_recurse_is_first_non_filter = quorum_recurse_is_first_non_filter,
|
|
};
|
|
|
|
static void bdrv_quorum_init(void)
|
|
{
|
|
if (!qcrypto_hash_supports(QCRYPTO_HASH_ALG_SHA256)) {
|
|
/* SHA256 hash support is required for quorum device */
|
|
return;
|
|
}
|
|
bdrv_register(&bdrv_quorum);
|
|
}
|
|
|
|
block_init(bdrv_quorum_init);
|