ocfs2: Add the local node id to the handshake.

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>

1 files changed, 173 insertions, 49 deletions

diff --git a/fs/ocfs2/stack_user.c b/fs/ocfs2/stack_user.c
index a5e58e2b9d59..43e6105369c6 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;