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Commit f6656d26 authored by Sunil Mushran's avatar Sunil Mushran Committed by Joel Becker
Browse files

ocfs2/cluster: Make fence method configurable - v2 



By default, o2cb fences the box by calling emergency_restart(). While this
scheme works well in production, it comes in the way during testing as it
does not let the tester take stack/core dumps for analysis.

This patch allows user to dynamically change the fence method to panic() by:
# echo "panic" > /sys/kernel/config/cluster/<clustername>/fence_method

Signed-off-by: default avatarSunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: default avatarJoel Becker <joel.becker@oracle.com>
parent 57b09bb5

fs/ocfs2/cluster/nodemanager.c

+51 −0
Original line number Diff line number Diff line
@@ -35,6 +35,10 @@ 
 * cluster references throughout where nodes are looked up */

struct o2nm_cluster *o2nm_single_cluster = NULL;



char *o2nm_fence_method_desc[O2NM_FENCE_METHODS] = {

		"reset",	/* O2NM_FENCE_RESET */

		"panic",	/* O2NM_FENCE_PANIC */

};



struct o2nm_node *o2nm_get_node_by_num(u8 node_num)

{
@@ -579,6 +583,43 @@ static ssize_t o2nm_cluster_attr_reconnect_delay_ms_write( 
	return o2nm_cluster_attr_write(page, count,

	                               &cluster->cl_reconnect_delay_ms);

}



static ssize_t o2nm_cluster_attr_fence_method_read(

	struct o2nm_cluster *cluster, char *page)

{

	ssize_t ret = 0;



	if (cluster)

		ret = sprintf(page, "%s\n",

			      o2nm_fence_method_desc[cluster->cl_fence_method]);

	return ret;

}



static ssize_t o2nm_cluster_attr_fence_method_write(

	struct o2nm_cluster *cluster, const char *page, size_t count)

{

	unsigned int i;



	if (page[count - 1] != '\n')

		goto bail;



	for (i = 0; i < O2NM_FENCE_METHODS; ++i) {

		if (count != strlen(o2nm_fence_method_desc[i]) + 1)

			continue;

		if (strncasecmp(page, o2nm_fence_method_desc[i], count - 1))

			continue;

		if (cluster->cl_fence_method != i) {

			printk(KERN_INFO "ocfs2: Changing fence method to %s\n",

			       o2nm_fence_method_desc[i]);

			cluster->cl_fence_method = i;

		}

		return count;

	}



bail:

	return -EINVAL;

}



static struct o2nm_cluster_attribute o2nm_cluster_attr_idle_timeout_ms = {

	.attr	= { .ca_owner = THIS_MODULE,

		    .ca_name = "idle_timeout_ms",
@@ -603,10 +644,19 @@ static struct o2nm_cluster_attribute o2nm_cluster_attr_reconnect_delay_ms = { 
	.store	= o2nm_cluster_attr_reconnect_delay_ms_write,

};



static struct o2nm_cluster_attribute o2nm_cluster_attr_fence_method = {

	.attr	= { .ca_owner = THIS_MODULE,

		    .ca_name = "fence_method",

		    .ca_mode = S_IRUGO | S_IWUSR },

	.show	= o2nm_cluster_attr_fence_method_read,

	.store	= o2nm_cluster_attr_fence_method_write,

};



static struct configfs_attribute *o2nm_cluster_attrs[] = {

	&o2nm_cluster_attr_idle_timeout_ms.attr,

	&o2nm_cluster_attr_keepalive_delay_ms.attr,

	&o2nm_cluster_attr_reconnect_delay_ms.attr,

	&o2nm_cluster_attr_fence_method.attr,

	NULL,

};

static ssize_t o2nm_cluster_show(struct config_item *item,
@@ -778,6 +828,7 @@ static struct config_group *o2nm_cluster_group_make_group(struct config_group *g 
	cluster->cl_reconnect_delay_ms = O2NET_RECONNECT_DELAY_MS_DEFAULT;

	cluster->cl_idle_timeout_ms    = O2NET_IDLE_TIMEOUT_MS_DEFAULT;

	cluster->cl_keepalive_delay_ms = O2NET_KEEPALIVE_DELAY_MS_DEFAULT;

	cluster->cl_fence_method       = O2NM_FENCE_RESET;



	ret = &cluster->cl_group;

	o2nm_single_cluster = cluster;

fs/ocfs2/cluster/nodemanager.h

+7 −0
Original line number Diff line number Diff line
@@ -33,6 +33,12 @@ 
#include <linux/configfs.h>

#include <linux/rbtree.h>



enum o2nm_fence_method {

	O2NM_FENCE_RESET	= 0,

	O2NM_FENCE_PANIC,

	O2NM_FENCE_METHODS,	/* Number of fence methods */

};



struct o2nm_node {

	spinlock_t		nd_lock;

	struct config_item	nd_item;
@@ -58,6 +64,7 @@ struct o2nm_cluster { 
	unsigned int		cl_idle_timeout_ms;

	unsigned int		cl_keepalive_delay_ms;

	unsigned int		cl_reconnect_delay_ms;

	enum o2nm_fence_method	cl_fence_method;



	/* this bitmap is part of a hack for disk bitmap.. will go eventually. - zab */

	unsigned long	cl_nodes_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];

fs/ocfs2/cluster/quorum.c

+14 −2
Original line number Diff line number Diff line
@@ -74,8 +74,20 @@ static void o2quo_fence_self(void) 
	 * threads can still schedule, etc, etc */

	o2hb_stop_all_regions();



	printk("ocfs2 is very sorry to be fencing this system by restarting\n");

	switch (o2nm_single_cluster->cl_fence_method) {

	case O2NM_FENCE_PANIC:

		panic("*** ocfs2 is very sorry to be fencing this system by "

		      "panicing ***\n");

		break;

	default:

		WARN_ON(o2nm_single_cluster->cl_fence_method >=

			O2NM_FENCE_METHODS);

	case O2NM_FENCE_RESET:

		printk(KERN_ERR "*** ocfs2 is very sorry to be fencing this "

		       "system by restarting ***\n");

		emergency_restart();

		break;

	};

}



/* Indicate that a timeout occured on a hearbeat region write. The