From: Beno??t Canet <address@hidden>
Example of command line:
-drive if=virtio,driver=quorum,\
children.0.file.filename=1.raw,\
children.0.node-name=1.raw,\
children.0.driver=raw,\
children.1.file.filename=2.raw,\
children.1.node-name=2.raw,\
children.1.driver=raw,\
children.2.file.filename=3.raw,\
children.2.node-name=3.raw,\
children.2.driver=raw,\
vote-threshold=2
blkverify=on with vote-threshold=2 and two files can be passed to
emulate blkverify.
Signed-off-by: Benoit Canet <address@hidden>
---
block/quorum.c | 161 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
monitor.c | 3 ++
qapi-schema.json | 21 +++++++-
3 files changed, 184 insertions(+), 1 deletion(-)
diff --git a/block/quorum.c b/block/quorum.c
index 40832c0..18721ba 100644
--- a/block/quorum.c
+++ b/block/quorum.c
@@ -20,6 +20,9 @@
#define HASH_LENGTH 32
+#define QUORUM_OPT_VOTE_THRESHOLD "vote-threshold"
+#define QUORUM_OPT_BLKVERIFY "blkverify"
+
/* This union holds a vote hash value */
typedef union QuorumVoteValue {
char h[HASH_LENGTH]; /* SHA-256 hash */
@@ -672,12 +675,170 @@ static bool
quorum_recurse_is_first_non_filter(BlockDriverState *bs,
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",
+ },
+ { /* end of list */ }
+ },
+};
+
+static int quorum_open(BlockDriverState *bs, QDict *options, int flags,
+ Error **errp)
+{
+ BDRVQuorumState *s = bs->opaque;
+ Error *local_err = NULL;
+ QemuOpts *opts;
+ bool *opened;
+ QDict *sub = NULL;
+ QList *list = NULL;
+ const QListEntry *lentry;
+ const QDictEntry *dentry;
+ int i;
+ int ret = 0;
+
+ qdict_flatten(options);
+ qdict_extract_subqdict(options, &sub, "children.");
+ qdict_array_split(sub, &list);
+
+ /* count how many different children are present and validate
+ * qdict_size(sub) address the open by reference case
+ */
+ s->num_children = !qlist_size(list) ? qdict_size(sub) : 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 (error_is_set(&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;
+ }
+
+ /* 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");
+ }
+
+ /* allocate the children BlockDriverState array */
+ s->bs = g_new0(BlockDriverState *, s->num_children);
+ opened = g_new0(bool, s->num_children);
+
+ /* Open by file name or options dict (command line or QMP) */
+ if (s->num_children == qlist_size(list)) {
+ for (i = 0, lentry = qlist_first(list); lentry;
+ lentry = qlist_next(lentry), i++) {
+ QDict *d = qobject_to_qdict(lentry->value);
+ QINCREF(d);
+ ret = bdrv_open(&s->bs[i], NULL, NULL, d, flags, NULL, &local_err);