| /* |
| * 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 "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 { |
| BlockDriverState **bs; /* children BlockDriverStates */ |
| int num_children; /* children count */ |
| 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(QuorumAIOCB *acb, char *node_name, int ret) |
| { |
| const char *msg = NULL; |
| if (ret < 0) { |
| msg = strerror(-ret); |
| } |
| qapi_event_send_quorum_report_bad(!!msg, msg, node_name, |
| acb->sector_num, acb->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 (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 < s->num_children) { |
| 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++; |
| if (ret == 0) { |
| acb->success_count++; |
| } else { |
| quorum_report_bad(acb, sacb->aiocb->bs->node_name, ret); |
| } |
| 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(acb, s->bs[item->index]->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->bs[item->index], 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->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 BlockAIOCB *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 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->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_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; |
| |
| if (!qcrypto_hash_supports(QCRYPTO_HASH_ALG_SHA256)) { |
| error_setg(errp, |
| "SHA256 hash support is required for quorum device"); |
| return -EINVAL; |
| } |
| |
| 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 < 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; i < s->num_children; i++) { |
| char indexstr[32]; |
| ret = snprintf(indexstr, 32, "children.%d", i); |
| assert(ret < 32); |
| |
| ret = bdrv_open_image(&s->bs[i], NULL, options, indexstr, bs, |
| &child_format, false, &local_err); |
| 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); |
| } |
| 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_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_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); |
