ocfs2: Add the local node id to the handshake.
Joel Becker [Wed, 20 Feb 2008 22:44:34 +0000 (14:44 -0800)]
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@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

fs/ocfs2/stack_user.c

index a5e58e2..43e6105 100644 (file)
  * 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>
  *
  */
 #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;