diff options
Diffstat (limited to 'block/quorum.c')
| -rw-r--r-- | block/quorum.c | 97 |
1 files changed, 91 insertions, 6 deletions
diff --git a/block/quorum.c b/block/quorum.c index 86802d306b..d5ee9c0059 100644 --- a/block/quorum.c +++ b/block/quorum.c @@ -23,6 +23,7 @@ #define QUORUM_OPT_VOTE_THRESHOLD "vote-threshold" #define QUORUM_OPT_BLKVERIFY "blkverify" +#define QUORUM_OPT_REWRITE "rewrite-corrupted" /* This union holds a vote hash value */ typedef union QuorumVoteValue { @@ -70,6 +71,9 @@ typedef struct BDRVQuorumState { * 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. + */ } BDRVQuorumState; typedef struct QuorumAIOCB QuorumAIOCB; @@ -105,13 +109,17 @@ struct QuorumAIOCB { 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; }; -static void quorum_vote(QuorumAIOCB *acb); +static bool quorum_vote(QuorumAIOCB *acb); static void quorum_aio_cancel(BlockDriverAIOCB *blockacb) { @@ -183,6 +191,7 @@ static QuorumAIOCB *quorum_aio_get(BDRVQuorumState *s, 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; @@ -232,11 +241,27 @@ static bool quorum_has_too_much_io_failed(QuorumAIOCB *acb) 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 void quorum_aio_cb(void *opaque, int ret) { QuorumChildRequest *sacb = opaque; QuorumAIOCB *acb = sacb->parent; BDRVQuorumState *s = acb->common.bs->opaque; + bool rewrite = false; sacb->ret = ret; acb->count++; @@ -253,12 +278,15 @@ static void quorum_aio_cb(void *opaque, int ret) /* Do the vote on read */ if (acb->is_read) { - quorum_vote(acb); + rewrite = quorum_vote(acb); } else { quorum_has_too_much_io_failed(acb); } - quorum_aio_finalize(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, @@ -278,6 +306,43 @@ static void quorum_report_bad_versions(BDRVQuorumState *s, } } +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_copy_qiov(QEMUIOVector *dest, QEMUIOVector *source) { int i; @@ -468,16 +533,17 @@ static int quorum_vote_error(QuorumAIOCB *acb) return ret; } -static void quorum_vote(QuorumAIOCB *acb) +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; + return false; } /* get the index of the first successful read */ @@ -505,7 +571,7 @@ static void quorum_vote(QuorumAIOCB *acb) /* Every successful read agrees */ if (quorum) { quorum_copy_qiov(acb->qiov, &acb->qcrs[i].qiov); - return; + return false; } /* compute hashes for each successful read, also store indexes */ @@ -538,9 +604,15 @@ static void quorum_vote(QuorumAIOCB *acb) /* 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 *quorum_aio_readv(BlockDriverState *bs, @@ -705,6 +777,11 @@ static QemuOptsList quorum_runtime_opts = { .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", + }, { /* end of list */ } }, }; @@ -766,6 +843,14 @@ static int quorum_open(BlockDriverState *bs, QDict *options, int flags, "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); |