Attachment 597007 Details for Bug 838047 – proposed patch

[patch] proposed patch

838047.patch (text/plain), 3.67 KB, created by Fabio Massimo Di Nitto on 2012-07-09 06:39:23 UTC

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Creator: Fabio Massimo Di Nitto

Created: 2012-07-09 06:39:23 UTC

Size: 3.67 KB

patch

obsolete

>commit ed1d76c919f8e9d7e0652969b3f8584b150f38bd
>Author: Fabio M. Di Nitto <fdinitto@redhat.com>
>Date:   Mon Jul 9 08:33:37 2012 +0200
>
>    qdiskd: restrict master_wins to 2 node cluster
>    
>    given enough mingling of cluster.conf it was possible to
>    break quorum rule #1: there is only one quorum in a cluster at
>    any given time.
>    
>    this change restricts master_wins to 2 node cluster only
>    and provides extra feedback to the user (via logging) on why
>    the mode is disabled.
>    
>    Resolves: rhbz#838047
>    
>    Signed-off-by: Fabio M. Di Nitto <fdinitto@redhat.com>
>
>diff --git a/cman/man/qdisk.5 b/cman/man/qdisk.5
>index ca974fa..938ed69 100644
>--- a/cman/man/qdisk.5
>+++ b/cman/man/qdisk.5
>@@ -297,8 +297,9 @@ and qdiskd's timeout (interval*tko) should be less than half of
> Totem's token timeout.  See section 3.3.1 for more information.
> 
> This option only takes effect if there are no heuristics
>-configured.  Usage of this option in configurations with more than
>-two cluster nodes is undefined and should not be done.
>+configured and it is valid only for 2 node cluster.
>+This option is automatically disabled if heuristics are
>+defined or cluster has more than 2 nodes configured.
> 
> In a two-node cluster with no heuristics and no defined vote
> count (see above), this mode is turned by default.  If enabled in
>diff --git a/cman/qdisk/disk.h b/cman/qdisk/disk.h
>index fd80fa6..1792377 100644
>--- a/cman/qdisk/disk.h
>+++ b/cman/qdisk/disk.h
>@@ -249,6 +249,7 @@ typedef struct {
> 	int qc_master;		/* Master?! */
> 	int qc_config;
> 	int qc_token_timeout;
>+	int qc_auto_votes;
> 	disk_node_state_t qc_disk_status;
> 	disk_node_state_t qc_status;
> 	run_flag_t qc_flags;
>diff --git a/cman/qdisk/main.c b/cman/qdisk/main.c
>index 32677a2..e14d534 100644
>--- a/cman/qdisk/main.c
>+++ b/cman/qdisk/main.c
>@@ -1444,7 +1444,7 @@ auto_qdisk_votes(int desc)
> 		logt_print(LOG_ERR, "Unable to determine qdiskd votes "
> 			   "automatically\n");
> 	else
>-		logt_print(LOG_DEBUG, "Setting votes to %d\n", ret);
>+		logt_print(LOG_DEBUG, "Setting autocalculated votes to %d\n", ret);
>  
>  	return (ret);
> }
>@@ -1606,6 +1606,8 @@ get_dynamic_config_data(qd_ctx *ctx, int ccsfd)
> 		ctx->qc_flags &= ~RF_AUTO_VOTES;
> 	}
> 
>+	ctx->qc_auto_votes = auto_qdisk_votes(ccsfd);
>+
> 	snprintf(query, sizeof(query), "/cluster/quorumd/@votes");
> 	if (ccs_get(ccsfd, query, &val) == 0) {
> 		ctx->qc_votes = atoi(val);
>@@ -1613,7 +1615,7 @@ get_dynamic_config_data(qd_ctx *ctx, int ccsfd)
> 		if (ctx->qc_votes < 0)
> 			ctx->qc_votes = 0;
> 	} else {
>-		ctx->qc_votes = auto_qdisk_votes(ccsfd);
>+		ctx->qc_votes = ctx->qc_auto_votes;
> 		if (ctx->qc_votes < 0) {
> 			if (ctx->qc_config) {
> 				logt_print(LOG_WARNING, "Unable to determine "
>@@ -1879,15 +1881,21 @@ get_config_data(qd_ctx *ctx, struct h_data *h, int maxh, int *cfh)
> 	*cfh = configure_heuristics(ccsfd, h, maxh,
> 				    ctx->qc_interval * (ctx->qc_tko - 1));
> 
>-	if (*cfh) {
>-		if (ctx->qc_flags & RF_MASTER_WINS) {
>-			logt_print(LOG_WARNING, "Master-wins mode disabled\n");
>+	if (ctx->qc_flags & RF_MASTER_WINS) {
>+		if (*cfh) {
>+			logt_print(LOG_WARNING, "Master-wins mode disabled "
>+						"(not compatible with heuristics)\n");
>+			ctx->qc_flags &= ~RF_MASTER_WINS;
>+		}
>+		if (ctx->qc_auto_votes != 1) {
>+			logt_print(LOG_WARNING, "Master-wins mode disabled "
>+						"(not compatible with more than 2 nodes)\n");
> 			ctx->qc_flags &= ~RF_MASTER_WINS;
> 		}
> 	} else {
> 		if (ctx->qc_flags & RF_AUTO_VOTES &&
>-		    !(ctx->qc_flags & RF_MASTER_WINS) &&
>-		    ctx->qc_votes == 1) { 
>+		    !*cfh &&
>+		    ctx->qc_auto_votes == 1) { 
> 			/* Two node cluster, no heuristics, 1 vote for
> 			 * quorum disk daemon.  Safe to enable master-wins.
> 			 * In fact, qdiskd without master-wins in this config

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