Commit de870ef0 authored by Joel Becker's avatar Joel Becker Committed by Mark Fasheh
Browse files

ocfs2: Introduce the DOWN message to ocfs2_control 



When the control daemon sees a node go down, it sends a DOWN message
through the ocfs2_control device.

Signed-off-by: default avatarJoel Becker <joel.becker@oracle.com>
Signed-off-by: default avatarMark Fasheh <mfasheh@suse.com>
parent 462c7e6a

fs/ocfs2/stack_user.c

+89 −5
Original line number Diff line number Diff line
@@ -35,9 +35,21 @@ 
 * of output is a supported protocol tag.  All protocol tags are a single

 * character followed by a two hex digit version number.  Currently the

 * only things supported is T01, for "Text-base version 0x01".  Next, the

 * client writes the version they would like to use.  If the version tag

 * written is unknown, -EINVAL is returned.  Once the negotiation is

 * complete, the client can start sending messages.

 * client writes the version they would like to use, including the newline.

 * Thus, the protocol tag is 'T01\n'.  If the version tag written is

 * 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:

 *

 *  DOWN<space><32-char-cap-hex-uuid><space><8-char-hex-nodenum><newline>

 *

 * eg:

 *

 *  DOWN 632A924FDD844190BDA93C0DF6B94899 00000001\n

 *

 * This is 47 characters.

 */



/*
@@ -49,6 +61,11 @@ 
#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_MESSAGE_DOWN_TOTAL_LEN	47

#define OCFS2_TEXT_UUID_LEN			32

#define OCFS2_CONTROL_MESSAGE_NODENUM_LEN	8



/*

 * ocfs2_live_connection is refcounted because the filesystem and
@@ -149,7 +166,7 @@ static void ocfs2_live_connection_drop(struct ocfs2_live_connection *c) 
	kfree(c);

}



static ssize_t ocfs2_control_cfu(char *target, size_t target_len,

static ssize_t 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 */
@@ -185,6 +202,73 @@ static ssize_t ocfs2_control_validate_handshake(struct file *file, 
	return count;

}



static void ocfs2_control_send_down(const char *uuid,

				    int nodenum)

{

	struct ocfs2_live_connection *c;



	mutex_lock(&ocfs2_control_lock);



	c = ocfs2_connection_find(uuid);

	if (c) {

		BUG_ON(c->oc_conn == NULL);

		c->oc_conn->cc_recovery_handler(nodenum,

						c->oc_conn->cc_recovery_data);

	}



	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;

};



static ssize_t ocfs2_control_message(struct file *file,

				     const char __user *buf,

				     size_t count)

{

	ssize_t ret;

	char *p = NULL;

	long nodenum;

	struct ocfs2_control_message_down msg;



	/* Try to catch padding issues */

	WARN_ON(offsetof(struct ocfs2_control_message_down, uuid) !=

		(sizeof(msg.tag) + sizeof(msg.space1)));



	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_DOWN,

		    strlen(OCFS2_CONTROL_MESSAGE_DOWN)))

		return -EINVAL;



	if ((msg.space1 != ' ') || (msg.space2 != ' ') ||

	    (msg.newline != '\n'))

		return -EINVAL;

	msg.space1 = msg.space2 = msg.newline = '\0';



	nodenum = simple_strtol(msg.nodestr, &p, 16);

	if (!p || *p)

		return -EINVAL;



	if ((nodenum == LONG_MIN) || (nodenum == LONG_MAX) ||

	    (nodenum > INT_MAX) || (nodenum < 0))

		return -ERANGE;



	ocfs2_control_send_down(msg.uuid, nodenum);



	return count;

}



static ssize_t ocfs2_control_write(struct file *file,

				   const char __user *buf,
@@ -204,7 +288,7 @@ static ssize_t ocfs2_control_write(struct file *file, 
			break;



		case OCFS2_CONTROL_HANDSHAKE_VALID:

			ret = count;  /* XXX */

			ret = ocfs2_control_message(file, buf, count);

			break;



		default: