This is the second part of the ocfs2_control handshake. After
negotiating the ocfs2_control protocol, the daemon tells the filesystem
what the local node id is via the SETN message.
Signed-off-by: Joel Becker <joel.becker@xxxxxxxxxx>
---
fs/ocfs2/stack_user.c | 222 ++++++++++++++++++++++++++++++++++++++-----------
1 files changed, 173 insertions(+), 49 deletions(-)
diff --git a/fs/ocfs2/stack_user.c b/fs/ocfs2/stack_user.c
index a5e58e2..43e6105 100644
--- a/fs/ocfs2/stack_user.c
+++ b/fs/ocfs2/stack_user.c
@@ -40,8 +40,18 @@
* unknown, -EINVAL is returned. Once the negotiation is complete, the
* client can start sending messages.
*
- * The T01 protocol only has one message, "DOWN". It has the following
- * syntax:
+ * The T01 protocol only has two messages. First is the "SETN" message.
+ * It has the following syntax:
+ *
+ * SETN<space><8-char-hex-nodenum><newline>
+ *
+ * This is 14 characters.
+ *
+ * The "SETN" message must be the first message following the protocol.
+ * It tells ocfs2_control the local node number.
+ *
+ * Once the local node number has been set, the "DOWN" message can be
+ * sent for node down notification. It has the following syntax:
*
* DOWN<space><32-char-cap-hex-uuid><space><8-char-hex-nodenum><newline>
*
@@ -58,11 +68,18 @@
*/
#define OCFS2_CONTROL_PROTO "T01\n"
#define OCFS2_CONTROL_PROTO_LEN 4
+
+/* Handshake states */
#define OCFS2_CONTROL_HANDSHAKE_INVALID (0)
#define OCFS2_CONTROL_HANDSHAKE_READ (1)
-#define OCFS2_CONTROL_HANDSHAKE_VALID (2)
-#define OCFS2_CONTROL_MESSAGE_DOWN "DOWN"
-#define OCFS2_CONTROL_MESSAGE_DOWN_LEN 4
+#define OCFS2_CONTROL_HANDSHAKE_PROTOCOL (2)
+#define OCFS2_CONTROL_HANDSHAKE_VALID (3)
+
+/* Messages */
+#define OCFS2_CONTROL_MESSAGE_OP_LEN 4
+#define OCFS2_CONTROL_MESSAGE_SETNODE_OP "SETN"
+#define OCFS2_CONTROL_MESSAGE_SETNODE_TOTAL_LEN 14
+#define OCFS2_CONTROL_MESSAGE_DOWN_OP "DOWN"
#define OCFS2_CONTROL_MESSAGE_DOWN_TOTAL_LEN 47
#define OCFS2_TEXT_UUID_LEN 32
#define OCFS2_CONTROL_MESSAGE_NODENUM_LEN 8
@@ -79,9 +96,35 @@ struct ocfs2_live_connection {
struct ocfs2_control_private {
struct list_head op_list;
int op_state;
+ int op_this_node;
+};
+
+/* SETN<space><8-char-hex-nodenum><newline> */
+struct ocfs2_control_message_setn {
+ char tag[OCFS2_CONTROL_MESSAGE_OP_LEN];
+ char space;
+ char nodestr[OCFS2_CONTROL_MESSAGE_NODENUM_LEN];
+ char newline;
+};
+
+/* DOWN<space><32-char-cap-hex-uuid><space><8-char-hex-nodenum><newline> */
+struct ocfs2_control_message_down {
+ char tag[OCFS2_CONTROL_MESSAGE_OP_LEN];
+ char space1;
+ char uuid[OCFS2_TEXT_UUID_LEN];
+ char space2;
+ char nodestr[OCFS2_CONTROL_MESSAGE_NODENUM_LEN];
+ char newline;
+};
+
+union ocfs2_control_message {
+ char tag[OCFS2_CONTROL_MESSAGE_OP_LEN];
+ struct ocfs2_control_message_setn u_setn;
+ struct ocfs2_control_message_down u_down;
};
static atomic_t ocfs2_control_opened;
+static int ocfs2_control_this_node = -1;
static LIST_HEAD(ocfs2_live_connection_list);
static LIST_HEAD(ocfs2_control_private_list);
@@ -166,38 +209,37 @@ static void ocfs2_live_connection_drop(struct ocfs2_live_connection *c)
kfree(c);
}
-static ssize_t ocfs2_control_cfu(void *target, size_t target_len,
- const char __user *buf, size_t count)
+static int ocfs2_control_cfu(void *target, size_t target_len,
+ const char __user *buf, size_t count)
{
/* The T01 expects write(2) calls to have exactly one command */
- if (count != target_len)
+ if ((count != target_len) ||
+ (count > sizeof(union ocfs2_control_message)))
return -EINVAL;
if (copy_from_user(target, buf, target_len))
return -EFAULT;
- return count;
+ return 0;
}
-static ssize_t ocfs2_control_validate_handshake(struct file *file,
- const char __user *buf,
- size_t count)
+static ssize_t ocfs2_control_validate_protocol(struct file *file,
+ const char __user *buf,
+ size_t count)
{
ssize_t ret;
char kbuf[OCFS2_CONTROL_PROTO_LEN];
ret = ocfs2_control_cfu(kbuf, OCFS2_CONTROL_PROTO_LEN,
buf, count);
- if (ret != count)
+ if (ret)
return ret;
if (strncmp(kbuf, OCFS2_CONTROL_PROTO, OCFS2_CONTROL_PROTO_LEN))
return -EINVAL;
- atomic_inc(&ocfs2_control_opened);
ocfs2_control_set_handshake_state(file,
- OCFS2_CONTROL_HANDSHAKE_VALID);
-
+ OCFS2_CONTROL_HANDSHAKE_PROTOCOL);
return count;
}
@@ -219,45 +261,92 @@ static void ocfs2_control_send_down(const char *uuid,
mutex_unlock(&ocfs2_control_lock);
}
-/* DOWN<space><32-char-cap-hex-uuid><space><8-char-hex-nodenum><newline> */
-struct ocfs2_control_message_down {
- char tag[OCFS2_CONTROL_MESSAGE_DOWN_LEN];
- char space1;
- char uuid[OCFS2_TEXT_UUID_LEN];
- char space2;
- char nodestr[OCFS2_CONTROL_MESSAGE_NODENUM_LEN];
- char newline;
-};
+/*
+ * Called whenever configuration elements are sent to /dev/ocfs2_control.
+ * If all configuration elements are present, try to set the global
+ * values. If not, return -EAGAIN. If there is a problem, return a
+ * different error.
+ */
+static int ocfs2_control_install_private(struct file *file)
+{
+ int rc = 0;
+ int set_p = 1;
+ struct ocfs2_control_private *p = file->private_data;
-static ssize_t ocfs2_control_message(struct file *file,
- const char __user *buf,
- size_t count)
+ BUG_ON(p->op_state != OCFS2_CONTROL_HANDSHAKE_PROTOCOL);
+
+ if (p->op_this_node < 0)
+ set_p = 0;
+
+ mutex_lock(&ocfs2_control_lock);
+ if (ocfs2_control_this_node < 0) {
+ if (set_p)
+ ocfs2_control_this_node = p->op_this_node;
+ } else if (ocfs2_control_this_node != p->op_this_node)
+ rc = -EINVAL;
+ mutex_unlock(&ocfs2_control_lock);
+
+ if (!rc && set_p) {
+ /* We set the global values successfully */
+ atomic_inc(&ocfs2_control_opened);
+ ocfs2_control_set_handshake_state(file,
+ OCFS2_CONTROL_HANDSHAKE_VALID);
+ }
+
+ return rc;
+}
+
+static int ocfs2_control_do_setnode_msg(struct file *file,
+ struct ocfs2_control_message_setn *msg)
{
- ssize_t ret;
- char *p = NULL;
long nodenum;
- struct ocfs2_control_message_down msg;
+ char *ptr = NULL;
+ struct ocfs2_control_private *p = file->private_data;
- /* Try to catch padding issues */
- WARN_ON(offsetof(struct ocfs2_control_message_down, uuid) !=
- (sizeof(msg.tag) + sizeof(msg.space1)));
+ if (ocfs2_control_get_handshake_state(file) !=
+ OCFS2_CONTROL_HANDSHAKE_PROTOCOL)
+ return -EINVAL;
- memset(&msg, 0, sizeof(struct ocfs2_control_message_down));
- ret = ocfs2_control_cfu(&msg, OCFS2_CONTROL_MESSAGE_DOWN_TOTAL_LEN,
- buf, count);
- if (ret != count)
- return ret;
+ if (strncmp(msg->tag, OCFS2_CONTROL_MESSAGE_SETNODE_OP,
+ OCFS2_CONTROL_MESSAGE_OP_LEN))
+ return -EINVAL;
+
+ if ((msg->space != ' ') || (msg->newline != '\n'))
+ return -EINVAL;
+ msg->space = msg->newline = '\0';
+
+ nodenum = simple_strtol(msg->nodestr, &ptr, 16);
+ if (!ptr || *ptr)
+ return -EINVAL;
+
+ if ((nodenum == LONG_MIN) || (nodenum == LONG_MAX) ||
+ (nodenum > INT_MAX) || (nodenum < 0))
+ return -ERANGE;
+ p->op_this_node = nodenum;
+
+ return ocfs2_control_install_private(file);
+}
+
+static int ocfs2_control_do_down_msg(struct file *file,
+ struct ocfs2_control_message_down *msg)
+{
+ long nodenum;
+ char *p = NULL;
+
+ if (ocfs2_control_get_handshake_state(file) !=
+ OCFS2_CONTROL_HANDSHAKE_VALID)
+ return -EINVAL;
- if (strncmp(msg.tag, OCFS2_CONTROL_MESSAGE_DOWN,
- strlen(OCFS2_CONTROL_MESSAGE_DOWN)))
+ if (strncmp(msg->tag, OCFS2_CONTROL_MESSAGE_DOWN_OP,
+ OCFS2_CONTROL_MESSAGE_OP_LEN))
return -EINVAL;
- if ((msg.space1 != ' ') || (msg.space2 != ' ') ||
- (msg.newline != '\n'))
+ if ((msg->space1 != ' ') || (msg->space2 != ' ') ||
+ (msg->newline != '\n'))
return -EINVAL;
- msg.space1 = msg.space2 = msg.newline = '\0';
+ msg->space1 = msg->space2 = msg->newline = '\0';
- nodenum = simple_strtol(msg.nodestr, &p, 16);
+ nodenum = simple_strtol(msg->nodestr, &p, 16);
if (!p || *p)
return -EINVAL;
@@ -265,9 +354,40 @@ static ssize_t ocfs2_control_message(struct file *file,
(nodenum > INT_MAX) || (nodenum < 0))
return -ERANGE;
- ocfs2_control_send_down(msg.uuid, nodenum);
+ ocfs2_control_send_down(msg->uuid, nodenum);
- return count;
+ return 0;
+}
+
+static ssize_t ocfs2_control_message(struct file *file,
+ const char __user *buf,
+ size_t count)
+{
+ ssize_t ret;
+ union ocfs2_control_message msg;
+
+ /* Try to catch padding issues */
+ WARN_ON(offsetof(struct ocfs2_control_message_down, uuid) !=
+ (sizeof(msg.u_down.tag) + sizeof(msg.u_down.space1)));
+
+ memset(&msg, 0, sizeof(union ocfs2_control_message));
+ ret = ocfs2_control_cfu(&msg, count, buf, count);
+ if (ret)
+ goto out;
+
+ if ((count == OCFS2_CONTROL_MESSAGE_SETNODE_TOTAL_LEN) &&
+ !strncmp(msg.tag, OCFS2_CONTROL_MESSAGE_SETNODE_OP,
+ OCFS2_CONTROL_MESSAGE_OP_LEN))
+ ret = ocfs2_control_do_setnode_msg(file, &msg.u_setn);
+ else if ((count == OCFS2_CONTROL_MESSAGE_DOWN_TOTAL_LEN) &&
+ !strncmp(msg.tag, OCFS2_CONTROL_MESSAGE_DOWN_OP,
+ OCFS2_CONTROL_MESSAGE_OP_LEN))
+ ret = ocfs2_control_do_down_msg(file, &msg.u_down);
+ else
+ ret = -EINVAL;
+
+out:
+ return ret ? ret : count;
}
static ssize_t ocfs2_control_write(struct file *file,
@@ -283,10 +403,11 @@ static ssize_t ocfs2_control_write(struct file *file,
break;
case OCFS2_CONTROL_HANDSHAKE_READ:
- ret = ocfs2_control_validate_handshake(file, buf,
- count);
+ ret = ocfs2_control_validate_protocol(file, buf,
+ count);
break;
+ case OCFS2_CONTROL_HANDSHAKE_PROTOCOL:
case OCFS2_CONTROL_HANDSHAKE_VALID:
ret = ocfs2_control_message(file, buf, count);
break;
@@ -350,6 +471,8 @@ static int ocfs2_control_release(struct inode *inode, struct file *file)
"an emergency restart!\n");
emergency_restart();
}
+ /* Last valid close clears the node number */
+ ocfs2_control_this_node = -1;
}
out:
@@ -370,6 +493,7 @@ static int ocfs2_control_open(struct inode *inode, struct file *file)
p = kzalloc(sizeof(struct ocfs2_control_private), GFP_KERNEL);
if (!p)
return -ENOMEM;
+ p->op_this_node = -1;
mutex_lock(&ocfs2_control_lock);
file->private_data = p;
--
1.5.3.8
--
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
