1098 lines
31 KiB
C
1098 lines
31 KiB
C
/*
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* Quorum Block filter
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*
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* Copyright (C) 2012-2014 Nodalink, EURL.
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*
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* Author:
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* Benoît Canet <benoit.canet@irqsave.net>
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*
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* Based on the design and code of blkverify.c (Copyright (C) 2010 IBM, Corp)
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* and blkmirror.c (Copyright (C) 2011 Red Hat, Inc).
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or later.
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* See the COPYING file in the top-level directory.
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*/
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#include <gnutls/gnutls.h>
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#include <gnutls/crypto.h>
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#include "block/block_int.h"
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#include "qapi/qmp/qbool.h"
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#include "qapi/qmp/qdict.h"
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#include "qapi/qmp/qint.h"
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#include "qapi/qmp/qjson.h"
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#include "qapi/qmp/qlist.h"
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#include "qapi/qmp/qstring.h"
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#include "qapi-event.h"
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#define HASH_LENGTH 32
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#define QUORUM_OPT_VOTE_THRESHOLD "vote-threshold"
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#define QUORUM_OPT_BLKVERIFY "blkverify"
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#define QUORUM_OPT_REWRITE "rewrite-corrupted"
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#define QUORUM_OPT_READ_PATTERN "read-pattern"
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/* This union holds a vote hash value */
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typedef union QuorumVoteValue {
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char h[HASH_LENGTH]; /* SHA-256 hash */
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int64_t l; /* simpler 64 bits hash */
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} QuorumVoteValue;
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/* A vote item */
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typedef struct QuorumVoteItem {
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int index;
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QLIST_ENTRY(QuorumVoteItem) next;
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} QuorumVoteItem;
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/* this structure is a vote version. A version is the set of votes sharing the
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* same vote value.
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* The set of votes will be tracked with the items field and its cardinality is
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* vote_count.
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*/
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typedef struct QuorumVoteVersion {
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QuorumVoteValue value;
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int index;
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int vote_count;
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QLIST_HEAD(, QuorumVoteItem) items;
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QLIST_ENTRY(QuorumVoteVersion) next;
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} QuorumVoteVersion;
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/* this structure holds a group of vote versions together */
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typedef struct QuorumVotes {
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QLIST_HEAD(, QuorumVoteVersion) vote_list;
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bool (*compare)(QuorumVoteValue *a, QuorumVoteValue *b);
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} QuorumVotes;
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/* the following structure holds the state of one quorum instance */
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typedef struct BDRVQuorumState {
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BlockDriverState **bs; /* children BlockDriverStates */
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int num_children; /* children count */
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int threshold; /* if less than threshold children reads gave the
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* same result a quorum error occurs.
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*/
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bool is_blkverify; /* true if the driver is in blkverify mode
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* Writes are mirrored on two children devices.
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* On reads the two children devices' contents are
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* compared and if a difference is spotted its
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* location is printed and the code aborts.
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* It is useful to debug other block drivers by
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* comparing them with a reference one.
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*/
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bool rewrite_corrupted;/* true if the driver must rewrite-on-read corrupted
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* block if Quorum is reached.
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*/
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QuorumReadPattern read_pattern;
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} BDRVQuorumState;
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typedef struct QuorumAIOCB QuorumAIOCB;
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/* Quorum will create one instance of the following structure per operation it
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* performs on its children.
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* So for each read/write operation coming from the upper layer there will be
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* $children_count QuorumChildRequest.
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*/
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typedef struct QuorumChildRequest {
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BlockDriverAIOCB *aiocb;
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QEMUIOVector qiov;
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uint8_t *buf;
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int ret;
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QuorumAIOCB *parent;
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} QuorumChildRequest;
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/* Quorum will use the following structure to track progress of each read/write
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* operation received by the upper layer.
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* This structure hold pointers to the QuorumChildRequest structures instances
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* used to do operations on each children and track overall progress.
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*/
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struct QuorumAIOCB {
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BlockDriverAIOCB common;
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/* Request metadata */
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uint64_t sector_num;
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int nb_sectors;
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QEMUIOVector *qiov; /* calling IOV */
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QuorumChildRequest *qcrs; /* individual child requests */
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int count; /* number of completed AIOCB */
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int success_count; /* number of successfully completed AIOCB */
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int rewrite_count; /* number of replica to rewrite: count down to
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* zero once writes are fired
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*/
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QuorumVotes votes;
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bool is_read;
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int vote_ret;
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int child_iter; /* which child to read in fifo pattern */
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};
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static bool quorum_vote(QuorumAIOCB *acb);
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static void quorum_aio_cancel(BlockDriverAIOCB *blockacb)
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{
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QuorumAIOCB *acb = container_of(blockacb, QuorumAIOCB, common);
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BDRVQuorumState *s = acb->common.bs->opaque;
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int i;
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/* cancel all callbacks */
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for (i = 0; i < s->num_children; i++) {
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if (acb->qcrs[i].aiocb) {
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bdrv_aio_cancel_async(acb->qcrs[i].aiocb);
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}
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}
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}
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static AIOCBInfo quorum_aiocb_info = {
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.aiocb_size = sizeof(QuorumAIOCB),
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.cancel_async = quorum_aio_cancel,
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};
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static void quorum_aio_finalize(QuorumAIOCB *acb)
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{
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int i, ret = 0;
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if (acb->vote_ret) {
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ret = acb->vote_ret;
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}
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acb->common.cb(acb->common.opaque, ret);
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if (acb->is_read) {
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/* on the quorum case acb->child_iter == s->num_children - 1 */
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for (i = 0; i <= acb->child_iter; i++) {
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qemu_vfree(acb->qcrs[i].buf);
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qemu_iovec_destroy(&acb->qcrs[i].qiov);
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}
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}
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g_free(acb->qcrs);
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qemu_aio_unref(acb);
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}
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static bool quorum_sha256_compare(QuorumVoteValue *a, QuorumVoteValue *b)
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{
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return !memcmp(a->h, b->h, HASH_LENGTH);
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}
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static bool quorum_64bits_compare(QuorumVoteValue *a, QuorumVoteValue *b)
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{
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return a->l == b->l;
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}
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static QuorumAIOCB *quorum_aio_get(BDRVQuorumState *s,
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BlockDriverState *bs,
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QEMUIOVector *qiov,
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uint64_t sector_num,
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int nb_sectors,
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BlockDriverCompletionFunc *cb,
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void *opaque)
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{
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QuorumAIOCB *acb = qemu_aio_get(&quorum_aiocb_info, bs, cb, opaque);
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int i;
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acb->common.bs->opaque = s;
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acb->sector_num = sector_num;
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acb->nb_sectors = nb_sectors;
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acb->qiov = qiov;
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acb->qcrs = g_new0(QuorumChildRequest, s->num_children);
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acb->count = 0;
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acb->success_count = 0;
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acb->rewrite_count = 0;
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acb->votes.compare = quorum_sha256_compare;
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QLIST_INIT(&acb->votes.vote_list);
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acb->is_read = false;
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acb->vote_ret = 0;
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for (i = 0; i < s->num_children; i++) {
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acb->qcrs[i].buf = NULL;
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acb->qcrs[i].ret = 0;
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acb->qcrs[i].parent = acb;
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}
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return acb;
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}
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static void quorum_report_bad(QuorumAIOCB *acb, char *node_name, int ret)
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{
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const char *msg = NULL;
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if (ret < 0) {
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msg = strerror(-ret);
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}
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qapi_event_send_quorum_report_bad(!!msg, msg, node_name,
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acb->sector_num, acb->nb_sectors, &error_abort);
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}
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static void quorum_report_failure(QuorumAIOCB *acb)
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{
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const char *reference = acb->common.bs->device_name[0] ?
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acb->common.bs->device_name :
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acb->common.bs->node_name;
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qapi_event_send_quorum_failure(reference, acb->sector_num,
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acb->nb_sectors, &error_abort);
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}
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static int quorum_vote_error(QuorumAIOCB *acb);
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static bool quorum_has_too_much_io_failed(QuorumAIOCB *acb)
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{
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BDRVQuorumState *s = acb->common.bs->opaque;
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if (acb->success_count < s->threshold) {
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acb->vote_ret = quorum_vote_error(acb);
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quorum_report_failure(acb);
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return true;
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}
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return false;
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}
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static void quorum_rewrite_aio_cb(void *opaque, int ret)
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{
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QuorumAIOCB *acb = opaque;
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/* one less rewrite to do */
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acb->rewrite_count--;
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/* wait until all rewrite callbacks have completed */
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if (acb->rewrite_count) {
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return;
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}
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quorum_aio_finalize(acb);
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}
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static BlockDriverAIOCB *read_fifo_child(QuorumAIOCB *acb);
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static void quorum_copy_qiov(QEMUIOVector *dest, QEMUIOVector *source)
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{
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int i;
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assert(dest->niov == source->niov);
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assert(dest->size == source->size);
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for (i = 0; i < source->niov; i++) {
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assert(dest->iov[i].iov_len == source->iov[i].iov_len);
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memcpy(dest->iov[i].iov_base,
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source->iov[i].iov_base,
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source->iov[i].iov_len);
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}
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}
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static void quorum_aio_cb(void *opaque, int ret)
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{
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QuorumChildRequest *sacb = opaque;
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QuorumAIOCB *acb = sacb->parent;
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BDRVQuorumState *s = acb->common.bs->opaque;
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bool rewrite = false;
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if (acb->is_read && s->read_pattern == QUORUM_READ_PATTERN_FIFO) {
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/* We try to read next child in FIFO order if we fail to read */
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if (ret < 0 && ++acb->child_iter < s->num_children) {
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read_fifo_child(acb);
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return;
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}
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if (ret == 0) {
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quorum_copy_qiov(acb->qiov, &acb->qcrs[acb->child_iter].qiov);
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}
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acb->vote_ret = ret;
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quorum_aio_finalize(acb);
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return;
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}
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sacb->ret = ret;
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acb->count++;
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if (ret == 0) {
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acb->success_count++;
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} else {
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quorum_report_bad(acb, sacb->aiocb->bs->node_name, ret);
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}
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assert(acb->count <= s->num_children);
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assert(acb->success_count <= s->num_children);
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if (acb->count < s->num_children) {
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return;
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}
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/* Do the vote on read */
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if (acb->is_read) {
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rewrite = quorum_vote(acb);
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} else {
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quorum_has_too_much_io_failed(acb);
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}
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/* if no rewrite is done the code will finish right away */
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if (!rewrite) {
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quorum_aio_finalize(acb);
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}
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}
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static void quorum_report_bad_versions(BDRVQuorumState *s,
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QuorumAIOCB *acb,
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QuorumVoteValue *value)
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{
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QuorumVoteVersion *version;
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QuorumVoteItem *item;
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QLIST_FOREACH(version, &acb->votes.vote_list, next) {
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if (acb->votes.compare(&version->value, value)) {
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continue;
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}
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QLIST_FOREACH(item, &version->items, next) {
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quorum_report_bad(acb, s->bs[item->index]->node_name, 0);
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}
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}
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}
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static bool quorum_rewrite_bad_versions(BDRVQuorumState *s, QuorumAIOCB *acb,
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QuorumVoteValue *value)
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{
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QuorumVoteVersion *version;
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QuorumVoteItem *item;
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int count = 0;
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/* first count the number of bad versions: done first to avoid concurrency
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* issues.
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*/
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QLIST_FOREACH(version, &acb->votes.vote_list, next) {
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if (acb->votes.compare(&version->value, value)) {
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continue;
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}
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QLIST_FOREACH(item, &version->items, next) {
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count++;
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}
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}
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/* quorum_rewrite_aio_cb will count down this to zero */
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acb->rewrite_count = count;
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/* now fire the correcting rewrites */
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QLIST_FOREACH(version, &acb->votes.vote_list, next) {
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if (acb->votes.compare(&version->value, value)) {
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continue;
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}
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QLIST_FOREACH(item, &version->items, next) {
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bdrv_aio_writev(s->bs[item->index], acb->sector_num, acb->qiov,
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acb->nb_sectors, quorum_rewrite_aio_cb, acb);
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}
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}
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/* return true if any rewrite is done else false */
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return count;
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}
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static void quorum_count_vote(QuorumVotes *votes,
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QuorumVoteValue *value,
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int index)
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{
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QuorumVoteVersion *v = NULL, *version = NULL;
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QuorumVoteItem *item;
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/* look if we have something with this hash */
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QLIST_FOREACH(v, &votes->vote_list, next) {
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if (votes->compare(&v->value, value)) {
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version = v;
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break;
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}
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}
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/* It's a version not yet in the list add it */
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if (!version) {
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version = g_new0(QuorumVoteVersion, 1);
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QLIST_INIT(&version->items);
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memcpy(&version->value, value, sizeof(version->value));
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version->index = index;
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version->vote_count = 0;
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QLIST_INSERT_HEAD(&votes->vote_list, version, next);
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}
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version->vote_count++;
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item = g_new0(QuorumVoteItem, 1);
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item->index = index;
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QLIST_INSERT_HEAD(&version->items, item, next);
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}
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static void quorum_free_vote_list(QuorumVotes *votes)
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{
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QuorumVoteVersion *version, *next_version;
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QuorumVoteItem *item, *next_item;
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QLIST_FOREACH_SAFE(version, &votes->vote_list, next, next_version) {
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QLIST_REMOVE(version, next);
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QLIST_FOREACH_SAFE(item, &version->items, next, next_item) {
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QLIST_REMOVE(item, next);
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g_free(item);
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}
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g_free(version);
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}
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}
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static int quorum_compute_hash(QuorumAIOCB *acb, int i, QuorumVoteValue *hash)
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{
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int j, ret;
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gnutls_hash_hd_t dig;
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QEMUIOVector *qiov = &acb->qcrs[i].qiov;
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ret = gnutls_hash_init(&dig, GNUTLS_DIG_SHA256);
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if (ret < 0) {
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return ret;
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}
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for (j = 0; j < qiov->niov; j++) {
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ret = gnutls_hash(dig, qiov->iov[j].iov_base, qiov->iov[j].iov_len);
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if (ret < 0) {
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break;
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}
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}
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gnutls_hash_deinit(dig, (void *) hash);
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return ret;
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}
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static QuorumVoteVersion *quorum_get_vote_winner(QuorumVotes *votes)
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{
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int max = 0;
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QuorumVoteVersion *candidate, *winner = NULL;
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QLIST_FOREACH(candidate, &votes->vote_list, next) {
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if (candidate->vote_count > max) {
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max = candidate->vote_count;
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winner = candidate;
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}
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}
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return winner;
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}
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/* qemu_iovec_compare is handy for blkverify mode because it returns the first
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* differing byte location. Yet it is handcoded to compare vectors one byte
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* after another so it does not benefit from the libc SIMD optimizations.
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* quorum_iovec_compare is written for speed and should be used in the non
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* blkverify mode of quorum.
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*/
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static bool quorum_iovec_compare(QEMUIOVector *a, QEMUIOVector *b)
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{
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int i;
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int result;
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assert(a->niov == b->niov);
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for (i = 0; i < a->niov; i++) {
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assert(a->iov[i].iov_len == b->iov[i].iov_len);
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result = memcmp(a->iov[i].iov_base,
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b->iov[i].iov_base,
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a->iov[i].iov_len);
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if (result) {
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return false;
|
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}
|
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}
|
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|
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return true;
|
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}
|
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|
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static void GCC_FMT_ATTR(2, 3) quorum_err(QuorumAIOCB *acb,
|
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const char *fmt, ...)
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{
|
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va_list ap;
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|
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va_start(ap, fmt);
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fprintf(stderr, "quorum: sector_num=%" PRId64 " nb_sectors=%d ",
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acb->sector_num, acb->nb_sectors);
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vfprintf(stderr, fmt, ap);
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fprintf(stderr, "\n");
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va_end(ap);
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exit(1);
|
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}
|
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|
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static bool quorum_compare(QuorumAIOCB *acb,
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QEMUIOVector *a,
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QEMUIOVector *b)
|
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{
|
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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 BlockDriverAIOCB *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->bs[i], 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++) {
|
|
bdrv_aio_readv(s->bs[i], acb->sector_num, &acb->qcrs[i].qiov,
|
|
acb->nb_sectors, quorum_aio_cb, &acb->qcrs[i]);
|
|
}
|
|
|
|
return &acb->common;
|
|
}
|
|
|
|
static BlockDriverAIOCB *read_fifo_child(QuorumAIOCB *acb)
|
|
{
|
|
BDRVQuorumState *s = acb->common.bs->opaque;
|
|
|
|
acb->qcrs[acb->child_iter].buf = qemu_blockalign(s->bs[acb->child_iter],
|
|
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);
|
|
bdrv_aio_readv(s->bs[acb->child_iter], acb->sector_num,
|
|
&acb->qcrs[acb->child_iter].qiov, acb->nb_sectors,
|
|
quorum_aio_cb, &acb->qcrs[acb->child_iter]);
|
|
|
|
return &acb->common;
|
|
}
|
|
|
|
static BlockDriverAIOCB *quorum_aio_readv(BlockDriverState *bs,
|
|
int64_t sector_num,
|
|
QEMUIOVector *qiov,
|
|
int nb_sectors,
|
|
BlockDriverCompletionFunc *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 BlockDriverAIOCB *quorum_aio_writev(BlockDriverState *bs,
|
|
int64_t sector_num,
|
|
QEMUIOVector *qiov,
|
|
int nb_sectors,
|
|
BlockDriverCompletionFunc *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->bs[i], 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->bs[0]);
|
|
if (result < 0) {
|
|
return result;
|
|
}
|
|
for (i = 1; i < s->num_children; i++) {
|
|
int64_t value = bdrv_getlength(s->bs[i]);
|
|
if (value < 0) {
|
|
return value;
|
|
}
|
|
if (value != result) {
|
|
return -EIO;
|
|
}
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
static void quorum_invalidate_cache(BlockDriverState *bs, Error **errp)
|
|
{
|
|
BDRVQuorumState *s = bs->opaque;
|
|
Error *local_err = NULL;
|
|
int i;
|
|
|
|
for (i = 0; i < s->num_children; i++) {
|
|
bdrv_invalidate_cache(s->bs[i], &local_err);
|
|
if (local_err) {
|
|
error_propagate(errp, local_err);
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
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;
|
|
|
|
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->bs[i]);
|
|
result_value.l = result;
|
|
quorum_count_vote(&error_votes, &result_value, i);
|
|
}
|
|
|
|
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->bs[i],
|
|
candidate);
|
|
if (perm) {
|
|
return true;
|
|
}
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
static int quorum_valid_threshold(int threshold, int num_children, Error **errp)
|
|
{
|
|
|
|
if (threshold < 1) {
|
|
error_set(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;
|
|
QDict *sub = NULL;
|
|
QList *list = NULL;
|
|
const QListEntry *lentry;
|
|
int i;
|
|
int ret = 0;
|
|
|
|
qdict_flatten(options);
|
|
qdict_extract_subqdict(options, &sub, "children.");
|
|
qdict_array_split(sub, &list);
|
|
|
|
if (qdict_size(sub)) {
|
|
error_setg(&local_err, "Invalid option children.%s",
|
|
qdict_first(sub)->key);
|
|
ret = -EINVAL;
|
|
goto exit;
|
|
}
|
|
|
|
/* count how many different children are present */
|
|
s->num_children = qlist_size(list);
|
|
if (s->num_children < 2) {
|
|
error_setg(&local_err,
|
|
"Number of provided children must be greater than 1");
|
|
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);
|
|
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) {
|
|
/* and validate it against s->num_children */
|
|
ret = quorum_valid_threshold(s->threshold, s->num_children, &local_err);
|
|
if (ret < 0) {
|
|
goto exit;
|
|
}
|
|
|
|
/* 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 BlockDriverState array */
|
|
s->bs = g_new0(BlockDriverState *, s->num_children);
|
|
opened = g_new0(bool, s->num_children);
|
|
|
|
for (i = 0, lentry = qlist_first(list); lentry;
|
|
lentry = qlist_next(lentry), i++) {
|
|
QDict *d;
|
|
QString *string;
|
|
|
|
switch (qobject_type(lentry->value))
|
|
{
|
|
/* List of options */
|
|
case QTYPE_QDICT:
|
|
d = qobject_to_qdict(lentry->value);
|
|
QINCREF(d);
|
|
ret = bdrv_open(&s->bs[i], NULL, NULL, d, flags, NULL,
|
|
&local_err);
|
|
break;
|
|
|
|
/* QMP reference */
|
|
case QTYPE_QSTRING:
|
|
string = qobject_to_qstring(lentry->value);
|
|
ret = bdrv_open(&s->bs[i], NULL, qstring_get_str(string), NULL,
|
|
flags, NULL, &local_err);
|
|
break;
|
|
|
|
default:
|
|
error_setg(&local_err, "Specification of child block device %i "
|
|
"is invalid", i);
|
|
ret = -EINVAL;
|
|
}
|
|
|
|
if (ret < 0) {
|
|
goto close_exit;
|
|
}
|
|
opened[i] = true;
|
|
}
|
|
|
|
g_free(opened);
|
|
goto exit;
|
|
|
|
close_exit:
|
|
/* cleanup on error */
|
|
for (i = 0; i < s->num_children; i++) {
|
|
if (!opened[i]) {
|
|
continue;
|
|
}
|
|
bdrv_unref(s->bs[i]);
|
|
}
|
|
g_free(s->bs);
|
|
g_free(opened);
|
|
exit:
|
|
qemu_opts_del(opts);
|
|
/* propagate error */
|
|
if (local_err) {
|
|
error_propagate(errp, local_err);
|
|
}
|
|
QDECREF(list);
|
|
QDECREF(sub);
|
|
return ret;
|
|
}
|
|
|
|
static void quorum_close(BlockDriverState *bs)
|
|
{
|
|
BDRVQuorumState *s = bs->opaque;
|
|
int i;
|
|
|
|
for (i = 0; i < s->num_children; i++) {
|
|
bdrv_unref(s->bs[i]);
|
|
}
|
|
|
|
g_free(s->bs);
|
|
}
|
|
|
|
static void quorum_detach_aio_context(BlockDriverState *bs)
|
|
{
|
|
BDRVQuorumState *s = bs->opaque;
|
|
int i;
|
|
|
|
for (i = 0; i < s->num_children; i++) {
|
|
bdrv_detach_aio_context(s->bs[i]);
|
|
}
|
|
}
|
|
|
|
static void quorum_attach_aio_context(BlockDriverState *bs,
|
|
AioContext *new_context)
|
|
{
|
|
BDRVQuorumState *s = bs->opaque;
|
|
int i;
|
|
|
|
for (i = 0; i < s->num_children; i++) {
|
|
bdrv_attach_aio_context(s->bs[i], new_context);
|
|
}
|
|
}
|
|
|
|
static void quorum_refresh_filename(BlockDriverState *bs)
|
|
{
|
|
BDRVQuorumState *s = bs->opaque;
|
|
QDict *opts;
|
|
QList *children;
|
|
int i;
|
|
|
|
for (i = 0; i < s->num_children; i++) {
|
|
bdrv_refresh_filename(s->bs[i]);
|
|
if (!s->bs[i]->full_open_options) {
|
|
return;
|
|
}
|
|
}
|
|
|
|
children = qlist_new();
|
|
for (i = 0; i < s->num_children; i++) {
|
|
QINCREF(s->bs[i]->full_open_options);
|
|
qlist_append_obj(children, QOBJECT(s->bs[i]->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_int(s->is_blkverify)));
|
|
qdict_put_obj(opts, QUORUM_OPT_REWRITE,
|
|
QOBJECT(qbool_from_int(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_invalidate_cache = quorum_invalidate_cache,
|
|
|
|
.bdrv_detach_aio_context = quorum_detach_aio_context,
|
|
.bdrv_attach_aio_context = quorum_attach_aio_context,
|
|
|
|
.is_filter = true,
|
|
.bdrv_recurse_is_first_non_filter = quorum_recurse_is_first_non_filter,
|
|
};
|
|
|
|
static void bdrv_quorum_init(void)
|
|
{
|
|
bdrv_register(&bdrv_quorum);
|
|
}
|
|
|
|
block_init(bdrv_quorum_init);
|