Release 4.10 fs/dlm/lowcomms.c

/******************************************************************************
*******************************************************************************
**
**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
**  Copyright (C) 2004-2009 Red Hat, Inc.  All rights reserved.
**
**  This copyrighted material is made available to anyone wishing to use,
**  modify, copy, or redistribute it subject to the terms and conditions
**  of the GNU General Public License v.2.
**
*******************************************************************************
******************************************************************************/

/*
 * lowcomms.c
 *
 * This is the "low-level" comms layer.
 *
 * It is responsible for sending/receiving messages
 * from other nodes in the cluster.
 *
 * Cluster nodes are referred to by their nodeids. nodeids are
 * simply 32 bit numbers to the locking module - if they need to
 * be expanded for the cluster infrastructure then that is its
 * responsibility. It is this layer's
 * responsibility to resolve these into IP address or
 * whatever it needs for inter-node communication.
 *
 * The comms level is two kernel threads that deal mainly with
 * the receiving of messages from other nodes and passing them
 * up to the mid-level comms layer (which understands the
 * message format) for execution by the locking core, and
 * a send thread which does all the setting up of connections
 * to remote nodes and the sending of data. Threads are not allowed
 * to send their own data because it may cause them to wait in times
 * of high load. Also, this way, the sending thread can collect together
 * messages bound for one node and send them in one block.
 *
 * lowcomms will choose to use either TCP or SCTP as its transport layer
 * depending on the configuration variable 'protocol'. This should be set
 * to 0 (default) for TCP or 1 for SCTP. It should be configured using a
 * cluster-wide mechanism as it must be the same on all nodes of the cluster
 * for the DLM to function.
 *
 */

#include <asm/ioctls.h>
#include <net/sock.h>
#include <net/tcp.h>
#include <linux/pagemap.h>
#include <linux/file.h>
#include <linux/mutex.h>
#include <linux/sctp.h>
#include <linux/slab.h>
#include <net/sctp/sctp.h>
#include <net/ipv6.h>

#include "dlm_internal.h"
#include "lowcomms.h"
#include "midcomms.h"
#include "config.h"


#define NEEDED_RMEM (4*1024*1024)

#define CONN_HASH_SIZE 32

/* Number of messages to send before rescheduling */

#define MAX_SEND_MSG_COUNT 25


struct cbuf {
	
unsigned int base;
	
unsigned int len;
	
unsigned int mask;
};



static void cbuf_add(struct cbuf *cb, int n)
{
	cb->len += n;
}

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static int cbuf_data(struct cbuf *cb)
{
	return ((cb->base + cb->len) & cb->mask);
}

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static void cbuf_init(struct cbuf *cb, int size)
{
	cb->base = cb->len = 0;
	cb->mask = size-1;
}

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static void cbuf_eat(struct cbuf *cb, int n)
{
	cb->len  -= n;
	cb->base += n;
	cb->base &= cb->mask;
}

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static bool cbuf_empty(struct cbuf *cb)
{
	return cb->len == 0;
}

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struct connection {
	
struct socket *sock;	/* NULL if not connected */
	
uint32_t nodeid;	/* So we know who we are in the list */
	
struct mutex sock_mutex;
	
unsigned long flags;

#define CF_READ_PENDING 1

#define CF_WRITE_PENDING 2

#define CF_CONNECT_PENDING 3

#define CF_INIT_PENDING 4

#define CF_IS_OTHERCON 5

#define CF_CLOSE 6

#define CF_APP_LIMITED 7
	
struct list_head writequeue;  /* List of outgoing writequeue_entries */
	
spinlock_t writequeue_lock;
	
int (*rx_action) (struct connection *);	/* What to do when active */
	
void (*connect_action) (struct connection *);	/* What to do to connect */
	
struct page *rx_page;
	
struct cbuf cb;
	
int retries;

#define MAX_CONNECT_RETRIES 3
	
struct hlist_node list;
	
struct connection *othercon;
	
struct work_struct rwork; /* Receive workqueue */
	
struct work_struct swork; /* Send workqueue */
	
void (*orig_error_report)(struct sock *);
	
void (*orig_data_ready)(struct sock *);
	
void (*orig_state_change)(struct sock *);
	
void (*orig_write_space)(struct sock *);
};

#define sock2con(x) ((struct connection *)(x)->sk_user_data)

/* An entry waiting to be sent */

struct writequeue_entry {
	
struct list_head list;
	
struct page *page;
	
int offset;
	
int len;
	
int end;
	
int users;
	
struct connection *con;
};


struct dlm_node_addr {
	
struct list_head list;
	
int nodeid;
	
int addr_count;
	
int curr_addr_index;
	
struct sockaddr_storage *addr[DLM_MAX_ADDR_COUNT];
};

static LIST_HEAD(dlm_node_addrs);
static DEFINE_SPINLOCK(dlm_node_addrs_spin);


static struct sockaddr_storage *dlm_local_addr[DLM_MAX_ADDR_COUNT];

static int dlm_local_count;

static int dlm_allow_conn;

/* Work queues */

static struct workqueue_struct *recv_workqueue;

static struct workqueue_struct *send_workqueue;


static struct hlist_head connection_hash[CONN_HASH_SIZE];
static DEFINE_MUTEX(connections_lock);

static struct kmem_cache *con_cache;

static void process_recv_sockets(struct work_struct *work);
static void process_send_sockets(struct work_struct *work);


/* This is deliberately very simple because most clusters have simple
   sequential nodeids, so we should be able to go straight to a connection
   struct in the array */


static inline int nodeid_hash(int nodeid)
{
	return nodeid & (CONN_HASH_SIZE-1);
}

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static struct connection *__find_con(int nodeid)
{
	int r;
	struct connection *con;

	r = nodeid_hash(nodeid);

	hlist_for_each_entry(con, &connection_hash[r], list) {
		if (con->nodeid == nodeid)
			return con;
	}
	return NULL;
}

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/*
 * If 'allocation' is zero then we don't attempt to create a new
 * connection structure for this node.
 */


static struct connection *__nodeid2con(int nodeid, gfp_t alloc)
{
	struct connection *con = NULL;
	int r;

	con = __find_con(nodeid);
	if (con || !alloc)
		return con;

	con = kmem_cache_zalloc(con_cache, alloc);
	if (!con)
		return NULL;

	r = nodeid_hash(nodeid);
	hlist_add_head(&con->list, &connection_hash[r]);

	con->nodeid = nodeid;
	mutex_init(&con->sock_mutex);
	INIT_LIST_HEAD(&con->writequeue);
	spin_lock_init(&con->writequeue_lock);
	INIT_WORK(&con->swork, process_send_sockets);
	INIT_WORK(&con->rwork, process_recv_sockets);

	/* Setup action pointers for child sockets */
	if (con->nodeid) {
		struct connection *zerocon = __find_con(0);

		con->connect_action = zerocon->connect_action;
		if (!con->rx_action)
			con->rx_action = zerocon->rx_action;
	}

	return con;
}

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patrick caulfield
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david teigland
58
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1
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christine caulfield
christine caulfield
12
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1
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/* Loop round all connections */


static void foreach_conn(void (*conn_func)(struct connection *c))
{
	int i;
	struct hlist_node *n;
	struct connection *con;

	for (i = 0; i < CONN_HASH_SIZE; i++) {
		hlist_for_each_entry_safe(con, n, &connection_hash[i], list)
			conn_func(con);
	}
}

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static struct connection *nodeid2con(int nodeid, gfp_t allocation)
{
	struct connection *con;

	mutex_lock(&connections_lock);
	con = __nodeid2con(nodeid, allocation);
	mutex_unlock(&connections_lock);

	return con;
}

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patrick caulfield
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matthias kaehlcke
matthias kaehlcke
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static struct dlm_node_addr *find_node_addr(int nodeid)
{
	struct dlm_node_addr *na;

	list_for_each_entry(na, &dlm_node_addrs, list) {
		if (na->nodeid == nodeid)
			return na;
	}
	return NULL;
}

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static int addr_compare(struct sockaddr_storage *x, struct sockaddr_storage *y)
{
	switch (x->ss_family) {
	case AF_INET: {
		struct sockaddr_in *sinx = (struct sockaddr_in *)x;
		struct sockaddr_in *siny = (struct sockaddr_in *)y;
		if (sinx->sin_addr.s_addr != siny->sin_addr.s_addr)
			return 0;
		if (sinx->sin_port != siny->sin_port)
			return 0;
		break;
	}
	case AF_INET6: {
		struct sockaddr_in6 *sinx = (struct sockaddr_in6 *)x;
		struct sockaddr_in6 *siny = (struct sockaddr_in6 *)y;
		if (!ipv6_addr_equal(&sinx->sin6_addr, &siny->sin6_addr))
			return 0;
		if (sinx->sin6_port != siny->sin6_port)
			return 0;
		break;
	}
	default:
		return 0;
	}
	return 1;
}

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static int nodeid_to_addr(int nodeid, struct sockaddr_storage *sas_out,
			  struct sockaddr *sa_out, bool try_new_addr)
{
	struct sockaddr_storage sas;
	struct dlm_node_addr *na;

	if (!dlm_local_count)
		return -1;

	spin_lock(&dlm_node_addrs_spin);
	na = find_node_addr(nodeid);
	if (na && na->addr_count) {
		memcpy(&sas, na->addr[na->curr_addr_index],
		       sizeof(struct sockaddr_storage));

		if (try_new_addr) {
			na->curr_addr_index++;
			if (na->curr_addr_index == na->addr_count)
				na->curr_addr_index = 0;
		}
	}
	spin_unlock(&dlm_node_addrs_spin);

	if (!na)
		return -EEXIST;

	if (!na->addr_count)
		return -ENOENT;

	if (sas_out)
		memcpy(sas_out, &sas, sizeof(struct sockaddr_storage));

	if (!sa_out)
		return 0;

	if (dlm_local_addr[0]->ss_family == AF_INET) {
		struct sockaddr_in *in4  = (struct sockaddr_in *) &sas;
		struct sockaddr_in *ret4 = (struct sockaddr_in *) sa_out;
		ret4->sin_addr.s_addr = in4->sin_addr.s_addr;
	} else {
		struct sockaddr_in6 *in6  = (struct sockaddr_in6 *) &sas;
		struct sockaddr_in6 *ret6 = (struct sockaddr_in6 *) sa_out;
		ret6->sin6_addr = in6->sin6_addr;
	}

	return 0;
}

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patrick caulfield
42
16.67%
1
16.67%
mike christie
mike christie
32
12.70%
1
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marcelo ricardo leitner
marcelo ricardo leitner
21
8.33%
1
16.67%
steven whitehouse
steven whitehouse
2
0.79%
1
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252
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6
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static int addr_to_nodeid(struct sockaddr_storage *addr, int *nodeid)
{
	struct dlm_node_addr *na;
	int rv = -EEXIST;
	int addr_i;

	spin_lock(&dlm_node_addrs_spin);
	list_for_each_entry(na, &dlm_node_addrs, list) {
		if (!na->addr_count)
			continue;

		for (addr_i = 0; addr_i < na->addr_count; addr_i++) {
			if (addr_compare(na->addr[addr_i], addr)) {
				*nodeid = na->nodeid;
				rv = 0;
				goto unlock;
			}
		}
	}
unlock:
	spin_unlock(&dlm_node_addrs_spin);
	return rv;
}

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david teigland
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mike christie
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1
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int dlm_lowcomms_addr(int nodeid, struct sockaddr_storage *addr, int len)
{
	struct sockaddr_storage *new_addr;
	struct dlm_node_addr *new_node, *na;

	new_node = kzalloc(sizeof(struct dlm_node_addr), GFP_NOFS);
	if (!new_node)
		return -ENOMEM;

	new_addr = kzalloc(sizeof(struct sockaddr_storage), GFP_NOFS);
	if (!new_addr) {
		kfree(new_node);
		return -ENOMEM;
	}

	memcpy(new_addr, addr, len);

	spin_lock(&dlm_node_addrs_spin);
	na = find_node_addr(nodeid);
	if (!na) {
		new_node->nodeid = nodeid;
		new_node->addr[0] = new_addr;
		new_node->addr_count = 1;
		list_add(&new_node->list, &dlm_node_addrs);
		spin_unlock(&dlm_node_addrs_spin);
		return 0;
	}

	if (na->addr_count >= DLM_MAX_ADDR_COUNT) {
		spin_unlock(&dlm_node_addrs_spin);
		kfree(new_addr);
		kfree(new_node);
		return -ENOSPC;
	}

	na->addr[na->addr_count++] = new_addr;
	spin_unlock(&dlm_node_addrs_spin);
	kfree(new_node);
	return 0;
}

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david teigland
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patrick caulfield
5
2.43%
1
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alexey dobriyan
alexey dobriyan
1
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1
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/* Data available on socket or listen socket received a connect */


static void lowcomms_data_ready(struct sock *sk)
{
	struct connection *con = sock2con(sk);
	if (con && !test_and_set_bit(CF_READ_PENDING, &con->flags))
		queue_work(recv_workqueue, &con->rwork);
}

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patrick caulfield
38
82.61%
2
66.67%
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david teigland
8
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1
33.33%
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46
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3
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static void lowcomms_write_space(struct sock *sk)
{
	struct connection *con = sock2con(sk);

	if (!con)
		return;

	clear_bit(SOCK_NOSPACE, &con->sock->flags);

	if (test_and_clear_bit(CF_APP_LIMITED, &con->flags)) {
		con->sock->sk->sk_write_pending--;
		clear_bit(SOCKWQ_ASYNC_NOSPACE, &con->sock->flags);
	}

	if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags))
		queue_work(send_workqueue, &con->swork);
}

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david s. miller
david s. miller
51
52.58%
1
20.00%
patrick caulfield
patrick caulfield
32
32.99%
2
40.00%
david teigland
david teigland
13
13.40%
1
20.00%
eric dumazet
eric dumazet
1
1.03%
1
20.00%
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97
100.00%
5
100.00%



static inline void lowcomms_connect_sock(struct connection *con)
{
	if (test_bit(CF_CLOSE, &con->flags))
		return;
	if (!test_and_set_bit(CF_CONNECT_PENDING, &con->flags))
		queue_work(send_workqueue, &con->swork);
}

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patrick caulfield
23
47.92%
1
33.33%
lars marowsky-bree
lars marowsky-bree
13
27.08%
1
33.33%
david teigland
david teigland
12
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1
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48
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3
100.00%



static void lowcomms_state_change(struct sock *sk)
{
	/* SCTP layer is not calling sk_data_ready when the connection
         * is done, so we catch the signal through here. Also, it
         * doesn't switch socket state when entering shutdown, so we
         * skip the write in that case.
         */
	if (sk->sk_shutdown) {
		if (sk->sk_shutdown == RCV_SHUTDOWN)
			lowcomms_data_ready(sk);
	} else if (sk->sk_state == TCP_ESTABLISHED) {
		lowcomms_write_space(sk);
	}
}

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marcelo ricardo leitner
25
51.02%
1
33.33%
patrick caulfield
patrick caulfield
17
34.69%
1
33.33%
david teigland
david teigland
7
14.29%
1
33.33%
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49
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3
100.00%



int dlm_lowcomms_connect_node(int nodeid)
{
	struct connection *con;

	if (nodeid == dlm_our_nodeid())
		return 0;

	con = nodeid2con(nodeid, GFP_NOFS);
	if (!con)
		return -ENOMEM;
	lowcomms_connect_sock(con);
	return 0;
}

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christine caulfield
49
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49
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1
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static void lowcomms_error_report(struct sock *sk)
{
	struct connection *con;
	struct sockaddr_storage saddr;
	int buflen;
	void (*orig_report)(struct sock *) = NULL;

	read_lock_bh(&sk->sk_callback_lock);
	con = sock2con(sk);
	if (con == NULL)
		goto out;

	orig_report = con->orig_error_report;
	if (con->sock == NULL ||
	    kernel_getpeername(con->sock, (struct sockaddr *)&saddr, &buflen)) {
		printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
				   "sending to node %d, port %d, "
				   "sk_err=%d/%d\n", dlm_our_nodeid(),
				   con->nodeid, dlm_config.ci_tcp_port,
				   sk->sk_err, sk->sk_err_soft);
	} else if (saddr.ss_family == AF_INET) {
		struct sockaddr_in *sin4 = (struct sockaddr_in *)&saddr;

		printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
				   "sending to node %d at %pI4, port %d, "
				   "sk_err=%d/%d\n", dlm_our_nodeid(),
				   con->nodeid, &sin4->sin_addr.s_addr,
				   dlm_config.ci_tcp_port, sk->sk_err,
				   sk->sk_err_soft);
	} else {
		struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&saddr;

		printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
				   "sending to node %d at %u.%u.%u.%u, "
				   "port %d, sk_err=%d/%d\n", dlm_our_nodeid(),
				   con->nodeid, sin6->sin6_addr.s6_addr32[0],
				   sin6->sin6_addr.s6_addr32[1],
				   sin6->sin6_addr.s6_addr32[2],
				   sin6->sin6_addr.s6_addr32[3],
				   dlm_config.ci_tcp_port, sk->sk_err,
				   sk->sk_err_soft);
	}
out:
	read_unlock_bh(&sk->sk_callback_lock);
	if (orig_report)
		orig_report(sk);
}

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/* Note: sk_callback_lock must be locked before calling this function. */


static void save_callbacks(struct connection *con, struct sock *sk)
{
	con->orig_data_ready = sk->sk_data_ready;
	con->orig_state_change = sk->sk_state_change;
	con->orig_write_space = sk->sk_write_space;
	con->orig_error_report = sk->sk_error_report;
}

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robert s. peterson
robert s. peterson
21
43.75%
1
25.00%
patrick caulfield
patrick caulfield
16
33.33%
1
25.00%
david teigland
david teigland
10
20.83%
1
25.00%
ying xue
ying xue
1
2.08%
1
25.00%
Total
48
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4
100.00%



static void restore_callbacks(struct connection *con, struct sock *sk)
{
	write_lock_bh(&sk->sk_callback_lock);
	sk->sk_user_data = NULL;
	sk->sk_data_ready = con->orig_data_ready;
	sk->sk_state_change = con->orig_state_change;
	sk->sk_write_space = con->orig_write_space;
	sk->sk_error_report = con->orig_error_report;
	write_unlock_bh(&sk->sk_callback_lock);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
robert s. peterson
robert s. peterson
54
77.14%
1
25.00%
patrick caulfield
patrick caulfield
9
12.86%
1
25.00%
david teigland
david teigland
5
7.14%
1
25.00%
steven whitehouse
steven whitehouse
2
2.86%
1
25.00%
Total
70
100.00%
4
100.00%

/* Make a socket active */


static void add_sock(struct socket *sock, struct connection *con, bool save_cb)
{
	struct sock *sk = sock->sk;

	write_lock_bh(&sk->sk_callback_lock);
	con->sock = sock;

	sk->sk_user_data = con;
	if (save_cb)
		save_callbacks(con, sk);
	/* Install a data_ready callback */
	sk->sk_data_ready = lowcomms_data_ready;
	sk->sk_write_space = lowcomms_write_space;
	sk->sk_state_change = lowcomms_state_change;
	sk->sk_allocation = GFP_NOFS;
	sk->sk_error_report = lowcomms_error_report;
	write_unlock_bh(&sk->sk_callback_lock);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
robert s. peterson
robert s. peterson
92
93.88%
3
60.00%
steven whitehouse
steven whitehouse
5
5.10%
1
20.00%
patrick caulfield
patrick caulfield
1
1.02%
1
20.00%
Total
98
100.00%
5
100.00%

/* Add the port number to an IPv6 or 4 sockaddr and return the address
   length */


static void make_sockaddr(struct sockaddr_storage *saddr, uint16_t port,
			  int *addr_len)
{
	saddr->ss_family =  dlm_local_addr[0]->ss_family;
	if (saddr->ss_family == AF_INET) {
		struct sockaddr_in *in4_addr = (struct sockaddr_in *)saddr;
		in4_addr->sin_port = cpu_to_be16(port);
		*addr_len = sizeof(struct sockaddr_in);
		memset(&in4_addr->sin_zero, 0, sizeof(in4_addr->sin_zero));
	} else {
		struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)saddr;
		in6_addr->sin6_port = cpu_to_be16(port);
		*addr_len = sizeof(struct sockaddr_in6);
	}
	memset((char *)saddr + *addr_len, 0, sizeof(struct sockaddr_storage) - *addr_len);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
patrick caulfield
patrick caulfield
112
78.87%
2
66.67%
david teigland
david teigland
30
21.13%
1
33.33%
Total
142
100.00%
3
100.00%

/* Close a remote connection and tidy up */


static void close_connection(struct connection *con, bool and_other,
			     bool tx, bool rx)
{
	clear_bit(CF_CONNECT_PENDING, &con->flags);
	clear_bit(CF_WRITE_PENDING, &con->flags);
	if (tx && cancel_work_sync(&con->swork))
		log_print("canceled swork for node %d", con->nodeid);
	if (rx && cancel_work_sync(&con->rwork))
		log_print("canceled rwork for node %d", con->nodeid);

	mutex_lock(&con->sock_mutex);
	if (con->sock) {
		if (!test_bit(CF_IS_OTHERCON, &con->flags))
			restore_callbacks(con, con->sock->sk);
		sock_release(con->sock);
		con->sock = NULL;
	}
	if (con->othercon && and_other) {
		/* Will only re-enter once. */
		close_connection(con->othercon, false, true, true);
	}
	if (con->rx_page) {
		__free_page(con->rx_page);
		con->rx_page = NULL;
	}

	con->retries = 0;
	mutex_unlock(&con->sock_mutex);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
marcelo ricardo leitner
marcelo ricardo leitner
72
37.11%
1
14.29%
patrick caulfield
patrick caulfield
66
34.02%
4
57.14%
david teigland
david teigland
32
16.49%
1
14.29%
robert s. peterson
robert s. peterson
24
12.37%
1
14.29%
Total
194
100.00%
7
100.00%

/* Data received from remote end */


static int receive_from_sock(struct connection *con)
{
	int ret = 0;
	struct msghdr msg = {};
	struct kvec iov[2];
	unsigned len;
	int r;
	int call_again_soon = 0;
	int nvec;

	mutex_lock(&con->sock_mutex);

	if (con->sock == NULL) {
		ret = -EAGAIN;
		goto out_close;
	}
	if (con->nodeid == 0) {
		ret = -EINVAL;
		goto out_close;
	}

	if (con->rx_page == NULL) {
		/*
                 * This doesn't need to be atomic, but I think it should
                 * improve performance if it is.
                 */
		con->rx_page = alloc_page(GFP_ATOMIC);
		if (con->rx_page == NULL)
			goto out_resched;
		cbuf_init(&