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ocfs2/cluster: move locking into attribute store methods 

The test and separate set bit scheme was racy to start with, so move to do
a test_and_set_bit after doing the earlier error checks inside the actual
store methods.  Also remove the locking for the local attribute which
already has a different scheme to synchronize.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Christoph Hellwig 2015-10-03 15:32:57 +02:00 committed by Nicholas Bellinger
parent ea9ed9cff4
commit 13a83fc909
1 changed files with 19 additions and 35 deletions
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54
fs/ocfs2/cluster/nodemanager.c
View File

@ -188,7 +188,6 @@ enum {
O2NM_NODE_ATTR_NUM = 0,
O2NM_NODE_ATTR_PORT,
O2NM_NODE_ATTR_ADDRESS,
O2NM_NODE_ATTR_LOCAL,
};
static ssize_t o2nm_node_num_write(struct o2nm_node *node, const char *page,
@ -197,6 +196,7 @@ static ssize_t o2nm_node_num_write(struct o2nm_node *node, const char *page,
struct o2nm_cluster *cluster = to_o2nm_cluster_from_node(node);
unsigned long tmp;
char *p = (char *)page;
int ret = 0;
tmp = simple_strtoul(p, &p, 0);
if (!p || (*p && (*p != '\n')))
@ -215,15 +215,18 @@ static ssize_t o2nm_node_num_write(struct o2nm_node *node, const char *page,
write_lock(&cluster->cl_nodes_lock);
if (cluster->cl_nodes[tmp])
p = NULL;
ret = -EEXIST;
else if (test_and_set_bit(O2NM_NODE_ATTR_NUM,
&node->nd_set_attributes))
ret = -EBUSY;
else {
cluster->cl_nodes[tmp] = node;
node->nd_num = tmp;
set_bit(tmp, cluster->cl_nodes_bitmap);
}
write_unlock(&cluster->cl_nodes_lock);
if (p == NULL)
return -EEXIST;
if (ret)
return ret;
return count;
}
@ -247,6 +250,8 @@ static ssize_t o2nm_node_ipv4_port_write(struct o2nm_node *node,
if (tmp >= (u16)-1)
return -ERANGE;
if (test_and_set_bit(O2NM_NODE_ATTR_PORT, &node->nd_set_attributes))
return -EBUSY;
node->nd_ipv4_port = htons(tmp);
return count;
@ -282,6 +287,9 @@ static ssize_t o2nm_node_ipv4_address_write(struct o2nm_node *node,
write_lock(&cluster->cl_nodes_lock);
if (o2nm_node_ip_tree_lookup(cluster, ipv4_addr, &p, &parent))
ret = -EEXIST;
else if (test_and_set_bit(O2NM_NODE_ATTR_ADDRESS,
&node->nd_set_attributes))
ret = -EBUSY;
else {
rb_link_node(&node->nd_ip_node, parent, p);
rb_insert_color(&node->nd_ip_node, &cluster->cl_node_ip_tree);
@ -388,24 +396,13 @@ static struct o2nm_node_attribute o2nm_node_attr_local = {
};
static struct configfs_attribute *o2nm_node_attrs[] = {
[O2NM_NODE_ATTR_NUM] = &o2nm_node_attr_num.attr,
[O2NM_NODE_ATTR_PORT] = &o2nm_node_attr_ipv4_port.attr,
[O2NM_NODE_ATTR_ADDRESS] = &o2nm_node_attr_ipv4_address.attr,
[O2NM_NODE_ATTR_LOCAL] = &o2nm_node_attr_local.attr,
&o2nm_node_attr_num.attr,
&o2nm_node_attr_ipv4_port.attr,
&o2nm_node_attr_ipv4_address.attr,
&o2nm_node_attr_local.attr,
NULL,
};
static int o2nm_attr_index(struct configfs_attribute *attr)
{
int i;
for (i = 0; i < ARRAY_SIZE(o2nm_node_attrs); i++) {
if (attr == o2nm_node_attrs[i])
return i;
}
BUG();
return 0;
}
static ssize_t o2nm_node_show(struct config_item *item,
struct configfs_attribute *attr,
char *page)
@ -427,24 +424,11 @@ static ssize_t o2nm_node_store(struct config_item *item,
struct o2nm_node *node = to_o2nm_node(item);
struct o2nm_node_attribute *o2nm_node_attr =
container_of(attr, struct o2nm_node_attribute, attr);
ssize_t ret;
int attr_index = o2nm_attr_index(attr);
if (o2nm_node_attr->store == NULL) {
ret = -EINVAL;
goto out;
}
if (o2nm_node_attr->store == NULL)
return -EINVAL;
if (test_bit(attr_index, &node->nd_set_attributes))
return -EBUSY;
ret = o2nm_node_attr->store(node, page, count);
if (ret < count)
goto out;
set_bit(attr_index, &node->nd_set_attributes);
out:
return ret;
return o2nm_node_attr->store(node, page, count);
}
static struct configfs_item_operations o2nm_node_item_ops = {