linux/fs/dlm/lowcomms.c
David Teigland 573c24c4af dlm: always use GFP_NOFS
Replace all GFP_KERNEL and ls_allocation with GFP_NOFS.
ls_allocation would be GFP_KERNEL for userland lockspaces
and GFP_NOFS for file system lockspaces.

It was discovered that any lockspaces on the system can
affect all others by triggering memory reclaim in the
file system which could in turn call back into the dlm
to acquire locks, deadlocking dlm threads that were
shared by all lockspaces, like dlm_recv.

Signed-off-by: David Teigland <teigland@redhat.com>
2009-11-30 16:34:43 -06:00

1535 lines
37 KiB
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 <net/sctp/user.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
struct cbuf {
unsigned int base;
unsigned int len;
unsigned int mask;
};
static void cbuf_add(struct cbuf *cb, int n)
{
cb->len += n;
}
static int cbuf_data(struct cbuf *cb)
{
return ((cb->base + cb->len) & cb->mask);
}
static void cbuf_init(struct cbuf *cb, int size)
{
cb->base = cb->len = 0;
cb->mask = size-1;
}
static void cbuf_eat(struct cbuf *cb, int n)
{
cb->len -= n;
cb->base += n;
cb->base &= cb->mask;
}
static bool cbuf_empty(struct cbuf *cb)
{
return cb->len == 0;
}
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
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
int sctp_assoc;
struct hlist_node list;
struct connection *othercon;
struct work_struct rwork; /* Receive workqueue */
struct work_struct swork; /* Send workqueue */
};
#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;
};
static struct sockaddr_storage *dlm_local_addr[DLM_MAX_ADDR_COUNT];
static int dlm_local_count;
/* 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);
}
static struct connection *__find_con(int nodeid)
{
int r;
struct hlist_node *h;
struct connection *con;
r = nodeid_hash(nodeid);
hlist_for_each_entry(con, h, &connection_hash[r], list) {
if (con->nodeid == nodeid)
return con;
}
return NULL;
}
/*
* 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;
}
/* Loop round all connections */
static void foreach_conn(void (*conn_func)(struct connection *c))
{
int i;
struct hlist_node *h, *n;
struct connection *con;
for (i = 0; i < CONN_HASH_SIZE; i++) {
hlist_for_each_entry_safe(con, h, n, &connection_hash[i], list){
conn_func(con);
}
}
}
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;
}
/* This is a bit drastic, but only called when things go wrong */
static struct connection *assoc2con(int assoc_id)
{
int i;
struct hlist_node *h;
struct connection *con;
mutex_lock(&connections_lock);
for (i = 0 ; i < CONN_HASH_SIZE; i++) {
hlist_for_each_entry(con, h, &connection_hash[i], list) {
if (con && con->sctp_assoc == assoc_id) {
mutex_unlock(&connections_lock);
return con;
}
}
}
mutex_unlock(&connections_lock);
return NULL;
}
static int nodeid_to_addr(int nodeid, struct sockaddr *retaddr)
{
struct sockaddr_storage addr;
int error;
if (!dlm_local_count)
return -1;
error = dlm_nodeid_to_addr(nodeid, &addr);
if (error)
return error;
if (dlm_local_addr[0]->ss_family == AF_INET) {
struct sockaddr_in *in4 = (struct sockaddr_in *) &addr;
struct sockaddr_in *ret4 = (struct sockaddr_in *) retaddr;
ret4->sin_addr.s_addr = in4->sin_addr.s_addr;
} else {
struct sockaddr_in6 *in6 = (struct sockaddr_in6 *) &addr;
struct sockaddr_in6 *ret6 = (struct sockaddr_in6 *) retaddr;
ipv6_addr_copy(&ret6->sin6_addr, &in6->sin6_addr);
}
return 0;
}
/* Data available on socket or listen socket received a connect */
static void lowcomms_data_ready(struct sock *sk, int count_unused)
{
struct connection *con = sock2con(sk);
if (con && !test_and_set_bit(CF_READ_PENDING, &con->flags))
queue_work(recv_workqueue, &con->rwork);
}
static void lowcomms_write_space(struct sock *sk)
{
struct connection *con = sock2con(sk);
if (con && !test_and_set_bit(CF_WRITE_PENDING, &con->flags))
queue_work(send_workqueue, &con->swork);
}
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);
}
static void lowcomms_state_change(struct sock *sk)
{
if (sk->sk_state == TCP_ESTABLISHED)
lowcomms_write_space(sk);
}
int dlm_lowcomms_connect_node(int nodeid)
{
struct connection *con;
/* with sctp there's no connecting without sending */
if (dlm_config.ci_protocol != 0)
return 0;
if (nodeid == dlm_our_nodeid())
return 0;
con = nodeid2con(nodeid, GFP_NOFS);
if (!con)
return -ENOMEM;
lowcomms_connect_sock(con);
return 0;
}
/* Make a socket active */
static int add_sock(struct socket *sock, struct connection *con)
{
con->sock = sock;
/* Install a data_ready callback */
con->sock->sk->sk_data_ready = lowcomms_data_ready;
con->sock->sk->sk_write_space = lowcomms_write_space;
con->sock->sk->sk_state_change = lowcomms_state_change;
con->sock->sk->sk_user_data = con;
con->sock->sk->sk_allocation = GFP_NOFS;
return 0;
}
/* 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);
}
/* Close a remote connection and tidy up */
static void close_connection(struct connection *con, bool and_other)
{
mutex_lock(&con->sock_mutex);
if (con->sock) {
sock_release(con->sock);
con->sock = NULL;
}
if (con->othercon && and_other) {
/* Will only re-enter once. */
close_connection(con->othercon, false);
}
if (con->rx_page) {
__free_page(con->rx_page);
con->rx_page = NULL;
}
con->retries = 0;
mutex_unlock(&con->sock_mutex);
}
/* We only send shutdown messages to nodes that are not part of the cluster */
static void sctp_send_shutdown(sctp_assoc_t associd)
{
static char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
struct msghdr outmessage;
struct cmsghdr *cmsg;
struct sctp_sndrcvinfo *sinfo;
int ret;
struct connection *con;
con = nodeid2con(0,0);
BUG_ON(con == NULL);
outmessage.msg_name = NULL;
outmessage.msg_namelen = 0;
outmessage.msg_control = outcmsg;
outmessage.msg_controllen = sizeof(outcmsg);
outmessage.msg_flags = MSG_EOR;
cmsg = CMSG_FIRSTHDR(&outmessage);
cmsg->cmsg_level = IPPROTO_SCTP;
cmsg->cmsg_type = SCTP_SNDRCV;
cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo));
outmessage.msg_controllen = cmsg->cmsg_len;
sinfo = CMSG_DATA(cmsg);
memset(sinfo, 0x00, sizeof(struct sctp_sndrcvinfo));
sinfo->sinfo_flags |= MSG_EOF;
sinfo->sinfo_assoc_id = associd;
ret = kernel_sendmsg(con->sock, &outmessage, NULL, 0, 0);
if (ret != 0)
log_print("send EOF to node failed: %d", ret);
}
static void sctp_init_failed_foreach(struct connection *con)
{
con->sctp_assoc = 0;
if (test_and_clear_bit(CF_CONNECT_PENDING, &con->flags)) {
if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags))
queue_work(send_workqueue, &con->swork);
}
}
/* INIT failed but we don't know which node...
restart INIT on all pending nodes */
static void sctp_init_failed(void)
{
mutex_lock(&connections_lock);
foreach_conn(sctp_init_failed_foreach);
mutex_unlock(&connections_lock);
}
/* Something happened to an association */
static void process_sctp_notification(struct connection *con,
struct msghdr *msg, char *buf)
{
union sctp_notification *sn = (union sctp_notification *)buf;
if (sn->sn_header.sn_type == SCTP_ASSOC_CHANGE) {
switch (sn->sn_assoc_change.sac_state) {
case SCTP_COMM_UP:
case SCTP_RESTART:
{
/* Check that the new node is in the lockspace */
struct sctp_prim prim;
int nodeid;
int prim_len, ret;
int addr_len;
struct connection *new_con;
sctp_peeloff_arg_t parg;
int parglen = sizeof(parg);
int err;
/*
* We get this before any data for an association.
* We verify that the node is in the cluster and
* then peel off a socket for it.
*/
if ((int)sn->sn_assoc_change.sac_assoc_id <= 0) {
log_print("COMM_UP for invalid assoc ID %d",
(int)sn->sn_assoc_change.sac_assoc_id);
sctp_init_failed();
return;
}
memset(&prim, 0, sizeof(struct sctp_prim));
prim_len = sizeof(struct sctp_prim);
prim.ssp_assoc_id = sn->sn_assoc_change.sac_assoc_id;
ret = kernel_getsockopt(con->sock,
IPPROTO_SCTP,
SCTP_PRIMARY_ADDR,
(char*)&prim,
&prim_len);
if (ret < 0) {
log_print("getsockopt/sctp_primary_addr on "
"new assoc %d failed : %d",
(int)sn->sn_assoc_change.sac_assoc_id,
ret);
/* Retry INIT later */
new_con = assoc2con(sn->sn_assoc_change.sac_assoc_id);
if (new_con)
clear_bit(CF_CONNECT_PENDING, &con->flags);
return;
}
make_sockaddr(&prim.ssp_addr, 0, &addr_len);
if (dlm_addr_to_nodeid(&prim.ssp_addr, &nodeid)) {
int i;
unsigned char *b=(unsigned char *)&prim.ssp_addr;
log_print("reject connect from unknown addr");
for (i=0; i<sizeof(struct sockaddr_storage);i++)
printk("%02x ", b[i]);
printk("\n");
sctp_send_shutdown(prim.ssp_assoc_id);
return;
}
new_con = nodeid2con(nodeid, GFP_NOFS);
if (!new_con)
return;
/* Peel off a new sock */
parg.associd = sn->sn_assoc_change.sac_assoc_id;
ret = kernel_getsockopt(con->sock, IPPROTO_SCTP,
SCTP_SOCKOPT_PEELOFF,
(void *)&parg, &parglen);
if (ret < 0) {
log_print("Can't peel off a socket for "
"connection %d to node %d: err=%d",
parg.associd, nodeid, ret);
return;
}
new_con->sock = sockfd_lookup(parg.sd, &err);
if (!new_con->sock) {
log_print("sockfd_lookup error %d", err);
return;
}
add_sock(new_con->sock, new_con);
sockfd_put(new_con->sock);
log_print("connecting to %d sctp association %d",
nodeid, (int)sn->sn_assoc_change.sac_assoc_id);
/* Send any pending writes */
clear_bit(CF_CONNECT_PENDING, &new_con->flags);
clear_bit(CF_INIT_PENDING, &con->flags);
if (!test_and_set_bit(CF_WRITE_PENDING, &new_con->flags)) {
queue_work(send_workqueue, &new_con->swork);
}
if (!test_and_set_bit(CF_READ_PENDING, &new_con->flags))
queue_work(recv_workqueue, &new_con->rwork);
}
break;
case SCTP_COMM_LOST:
case SCTP_SHUTDOWN_COMP:
{
con = assoc2con(sn->sn_assoc_change.sac_assoc_id);
if (con) {
con->sctp_assoc = 0;
}
}
break;
/* We don't know which INIT failed, so clear the PENDING flags
* on them all. if assoc_id is zero then it will then try
* again */
case SCTP_CANT_STR_ASSOC:
{
log_print("Can't start SCTP association - retrying");
sctp_init_failed();
}
break;
default:
log_print("unexpected SCTP assoc change id=%d state=%d",
(int)sn->sn_assoc_change.sac_assoc_id,
sn->sn_assoc_change.sac_state);
}
}
}
/* 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;
char incmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
mutex_lock(&con->sock_mutex);
if (con->sock == NULL) {
ret = -EAGAIN;
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(&con->cb, PAGE_CACHE_SIZE);
}
/* Only SCTP needs these really */
memset(&incmsg, 0, sizeof(incmsg));
msg.msg_control = incmsg;
msg.msg_controllen = sizeof(incmsg);
/*
* iov[0] is the bit of the circular buffer between the current end
* point (cb.base + cb.len) and the end of the buffer.
*/
iov[0].iov_len = con->cb.base - cbuf_data(&con->cb);
iov[0].iov_base = page_address(con->rx_page) + cbuf_data(&con->cb);
iov[1].iov_len = 0;
nvec = 1;
/*
* iov[1] is the bit of the circular buffer between the start of the
* buffer and the start of the currently used section (cb.base)
*/
if (cbuf_data(&con->cb) >= con->cb.base) {
iov[0].iov_len = PAGE_CACHE_SIZE - cbuf_data(&con->cb);
iov[1].iov_len = con->cb.base;
iov[1].iov_base = page_address(con->rx_page);
nvec = 2;
}
len = iov[0].iov_len + iov[1].iov_len;
r = ret = kernel_recvmsg(con->sock, &msg, iov, nvec, len,
MSG_DONTWAIT | MSG_NOSIGNAL);
if (ret <= 0)
goto out_close;
/* Process SCTP notifications */
if (msg.msg_flags & MSG_NOTIFICATION) {
msg.msg_control = incmsg;
msg.msg_controllen = sizeof(incmsg);
process_sctp_notification(con, &msg,
page_address(con->rx_page) + con->cb.base);
mutex_unlock(&con->sock_mutex);
return 0;
}
BUG_ON(con->nodeid == 0);
if (ret == len)
call_again_soon = 1;
cbuf_add(&con->cb, ret);
ret = dlm_process_incoming_buffer(con->nodeid,
page_address(con->rx_page),
con->cb.base, con->cb.len,
PAGE_CACHE_SIZE);
if (ret == -EBADMSG) {
log_print("lowcomms: addr=%p, base=%u, len=%u, "
"iov_len=%u, iov_base[0]=%p, read=%d",
page_address(con->rx_page), con->cb.base, con->cb.len,
len, iov[0].iov_base, r);
}
if (ret < 0)
goto out_close;
cbuf_eat(&con->cb, ret);
if (cbuf_empty(&con->cb) && !call_again_soon) {
__free_page(con->rx_page);
con->rx_page = NULL;
}
if (call_again_soon)
goto out_resched;
mutex_unlock(&con->sock_mutex);
return 0;
out_resched:
if (!test_and_set_bit(CF_READ_PENDING, &con->flags))
queue_work(recv_workqueue, &con->rwork);
mutex_unlock(&con->sock_mutex);
return -EAGAIN;
out_close:
mutex_unlock(&con->sock_mutex);
if (ret != -EAGAIN) {
close_connection(con, false);
/* Reconnect when there is something to send */
}
/* Don't return success if we really got EOF */
if (ret == 0)
ret = -EAGAIN;
return ret;
}
/* Listening socket is busy, accept a connection */
static int tcp_accept_from_sock(struct connection *con)
{
int result;
struct sockaddr_storage peeraddr;
struct socket *newsock;
int len;
int nodeid;
struct connection *newcon;
struct connection *addcon;
memset(&peeraddr, 0, sizeof(peeraddr));
result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM,
IPPROTO_TCP, &newsock);
if (result < 0)
return -ENOMEM;
mutex_lock_nested(&con->sock_mutex, 0);
result = -ENOTCONN;
if (con->sock == NULL)
goto accept_err;
newsock->type = con->sock->type;
newsock->ops = con->sock->ops;
result = con->sock->ops->accept(con->sock, newsock, O_NONBLOCK);
if (result < 0)
goto accept_err;
/* Get the connected socket's peer */
memset(&peeraddr, 0, sizeof(peeraddr));
if (newsock->ops->getname(newsock, (struct sockaddr *)&peeraddr,
&len, 2)) {
result = -ECONNABORTED;
goto accept_err;
}
/* Get the new node's NODEID */
make_sockaddr(&peeraddr, 0, &len);
if (dlm_addr_to_nodeid(&peeraddr, &nodeid)) {
log_print("connect from non cluster node");
sock_release(newsock);
mutex_unlock(&con->sock_mutex);
return -1;
}
log_print("got connection from %d", nodeid);
/* Check to see if we already have a connection to this node. This
* could happen if the two nodes initiate a connection at roughly
* the same time and the connections cross on the wire.
* In this case we store the incoming one in "othercon"
*/
newcon = nodeid2con(nodeid, GFP_NOFS);
if (!newcon) {
result = -ENOMEM;
goto accept_err;
}
mutex_lock_nested(&newcon->sock_mutex, 1);
if (newcon->sock) {
struct connection *othercon = newcon->othercon;
if (!othercon) {
othercon = kmem_cache_zalloc(con_cache, GFP_NOFS);
if (!othercon) {
log_print("failed to allocate incoming socket");
mutex_unlock(&newcon->sock_mutex);
result = -ENOMEM;
goto accept_err;
}
othercon->nodeid = nodeid;
othercon->rx_action = receive_from_sock;
mutex_init(&othercon->sock_mutex);
INIT_WORK(&othercon->swork, process_send_sockets);
INIT_WORK(&othercon->rwork, process_recv_sockets);
set_bit(CF_IS_OTHERCON, &othercon->flags);
}
if (!othercon->sock) {
newcon->othercon = othercon;
othercon->sock = newsock;
newsock->sk->sk_user_data = othercon;
add_sock(newsock, othercon);
addcon = othercon;
}
else {
printk("Extra connection from node %d attempted\n", nodeid);
result = -EAGAIN;
mutex_unlock(&newcon->sock_mutex);
goto accept_err;
}
}
else {
newsock->sk->sk_user_data = newcon;
newcon->rx_action = receive_from_sock;
add_sock(newsock, newcon);
addcon = newcon;
}
mutex_unlock(&newcon->sock_mutex);
/*
* Add it to the active queue in case we got data
* beween processing the accept adding the socket
* to the read_sockets list
*/
if (!test_and_set_bit(CF_READ_PENDING, &addcon->flags))
queue_work(recv_workqueue, &addcon->rwork);
mutex_unlock(&con->sock_mutex);
return 0;
accept_err:
mutex_unlock(&con->sock_mutex);
sock_release(newsock);
if (result != -EAGAIN)
log_print("error accepting connection from node: %d", result);
return result;
}
static void free_entry(struct writequeue_entry *e)
{
__free_page(e->page);
kfree(e);
}
/* Initiate an SCTP association.
This is a special case of send_to_sock() in that we don't yet have a
peeled-off socket for this association, so we use the listening socket
and add the primary IP address of the remote node.
*/
static void sctp_init_assoc(struct connection *con)
{
struct sockaddr_storage rem_addr;
char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
struct msghdr outmessage;
struct cmsghdr *cmsg;
struct sctp_sndrcvinfo *sinfo;
struct connection *base_con;
struct writequeue_entry *e;
int len, offset;
int ret;
int addrlen;
struct kvec iov[1];
if (test_and_set_bit(CF_INIT_PENDING, &con->flags))
return;
if (con->retries++ > MAX_CONNECT_RETRIES)
return;
if (nodeid_to_addr(con->nodeid, (struct sockaddr *)&rem_addr)) {
log_print("no address for nodeid %d", con->nodeid);
return;
}
base_con = nodeid2con(0, 0);
BUG_ON(base_con == NULL);
make_sockaddr(&rem_addr, dlm_config.ci_tcp_port, &addrlen);
outmessage.msg_name = &rem_addr;
outmessage.msg_namelen = addrlen;
outmessage.msg_control = outcmsg;
outmessage.msg_controllen = sizeof(outcmsg);
outmessage.msg_flags = MSG_EOR;
spin_lock(&con->writequeue_lock);
if (list_empty(&con->writequeue)) {
spin_unlock(&con->writequeue_lock);
log_print("writequeue empty for nodeid %d", con->nodeid);
return;
}
e = list_first_entry(&con->writequeue, struct writequeue_entry, list);
len = e->len;
offset = e->offset;
spin_unlock(&con->writequeue_lock);
/* Send the first block off the write queue */
iov[0].iov_base = page_address(e->page)+offset;
iov[0].iov_len = len;
cmsg = CMSG_FIRSTHDR(&outmessage);
cmsg->cmsg_level = IPPROTO_SCTP;
cmsg->cmsg_type = SCTP_SNDRCV;
cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo));
sinfo = CMSG_DATA(cmsg);
memset(sinfo, 0x00, sizeof(struct sctp_sndrcvinfo));
sinfo->sinfo_ppid = cpu_to_le32(dlm_our_nodeid());
outmessage.msg_controllen = cmsg->cmsg_len;
ret = kernel_sendmsg(base_con->sock, &outmessage, iov, 1, len);
if (ret < 0) {
log_print("Send first packet to node %d failed: %d",
con->nodeid, ret);
/* Try again later */
clear_bit(CF_CONNECT_PENDING, &con->flags);
clear_bit(CF_INIT_PENDING, &con->flags);
}
else {
spin_lock(&con->writequeue_lock);
e->offset += ret;
e->len -= ret;
if (e->len == 0 && e->users == 0) {
list_del(&e->list);
free_entry(e);
}
spin_unlock(&con->writequeue_lock);
}
}
/* Connect a new socket to its peer */
static void tcp_connect_to_sock(struct connection *con)
{
int result = -EHOSTUNREACH;
struct sockaddr_storage saddr, src_addr;
int addr_len;
struct socket *sock = NULL;
if (con->nodeid == 0) {
log_print("attempt to connect sock 0 foiled");
return;
}
mutex_lock(&con->sock_mutex);
if (con->retries++ > MAX_CONNECT_RETRIES)
goto out;
/* Some odd races can cause double-connects, ignore them */
if (con->sock) {
result = 0;
goto out;
}
/* Create a socket to communicate with */
result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM,
IPPROTO_TCP, &sock);
if (result < 0)
goto out_err;
memset(&saddr, 0, sizeof(saddr));
if (dlm_nodeid_to_addr(con->nodeid, &saddr))
goto out_err;
sock->sk->sk_user_data = con;
con->rx_action = receive_from_sock;
con->connect_action = tcp_connect_to_sock;
add_sock(sock, con);
/* Bind to our cluster-known address connecting to avoid
routing problems */
memcpy(&src_addr, dlm_local_addr[0], sizeof(src_addr));
make_sockaddr(&src_addr, 0, &addr_len);
result = sock->ops->bind(sock, (struct sockaddr *) &src_addr,
addr_len);
if (result < 0) {
log_print("could not bind for connect: %d", result);
/* This *may* not indicate a critical error */
}
make_sockaddr(&saddr, dlm_config.ci_tcp_port, &addr_len);
log_print("connecting to %d", con->nodeid);
result =
sock->ops->connect(sock, (struct sockaddr *)&saddr, addr_len,
O_NONBLOCK);
if (result == -EINPROGRESS)
result = 0;
if (result == 0)
goto out;
out_err:
if (con->sock) {
sock_release(con->sock);
con->sock = NULL;
} else if (sock) {
sock_release(sock);
}
/*
* Some errors are fatal and this list might need adjusting. For other
* errors we try again until the max number of retries is reached.
*/
if (result != -EHOSTUNREACH && result != -ENETUNREACH &&
result != -ENETDOWN && result != -EINVAL
&& result != -EPROTONOSUPPORT) {
lowcomms_connect_sock(con);
result = 0;
}
out:
mutex_unlock(&con->sock_mutex);
return;
}
static struct socket *tcp_create_listen_sock(struct connection *con,
struct sockaddr_storage *saddr)
{
struct socket *sock = NULL;
int result = 0;
int one = 1;
int addr_len;
if (dlm_local_addr[0]->ss_family == AF_INET)
addr_len = sizeof(struct sockaddr_in);
else
addr_len = sizeof(struct sockaddr_in6);
/* Create a socket to communicate with */
result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM,
IPPROTO_TCP, &sock);
if (result < 0) {
log_print("Can't create listening comms socket");
goto create_out;
}
result = kernel_setsockopt(sock, SOL_SOCKET, SO_REUSEADDR,
(char *)&one, sizeof(one));
if (result < 0) {
log_print("Failed to set SO_REUSEADDR on socket: %d", result);
}
sock->sk->sk_user_data = con;
con->rx_action = tcp_accept_from_sock;
con->connect_action = tcp_connect_to_sock;
con->sock = sock;
/* Bind to our port */
make_sockaddr(saddr, dlm_config.ci_tcp_port, &addr_len);
result = sock->ops->bind(sock, (struct sockaddr *) saddr, addr_len);
if (result < 0) {
log_print("Can't bind to port %d", dlm_config.ci_tcp_port);
sock_release(sock);
sock = NULL;
con->sock = NULL;
goto create_out;
}
result = kernel_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
(char *)&one, sizeof(one));
if (result < 0) {
log_print("Set keepalive failed: %d", result);
}
result = sock->ops->listen(sock, 5);
if (result < 0) {
log_print("Can't listen on port %d", dlm_config.ci_tcp_port);
sock_release(sock);
sock = NULL;
goto create_out;
}
create_out:
return sock;
}
/* Get local addresses */
static void init_local(void)
{
struct sockaddr_storage sas, *addr;
int i;
dlm_local_count = 0;
for (i = 0; i < DLM_MAX_ADDR_COUNT - 1; i++) {
if (dlm_our_addr(&sas, i))
break;
addr = kmalloc(sizeof(*addr), GFP_NOFS);
if (!addr)
break;
memcpy(addr, &sas, sizeof(*addr));
dlm_local_addr[dlm_local_count++] = addr;
}
}
/* Bind to an IP address. SCTP allows multiple address so it can do
multi-homing */
static int add_sctp_bind_addr(struct connection *sctp_con,
struct sockaddr_storage *addr,
int addr_len, int num)
{
int result = 0;
if (num == 1)
result = kernel_bind(sctp_con->sock,
(struct sockaddr *) addr,
addr_len);
else
result = kernel_setsockopt(sctp_con->sock, SOL_SCTP,
SCTP_SOCKOPT_BINDX_ADD,
(char *)addr, addr_len);
if (result < 0)
log_print("Can't bind to port %d addr number %d",
dlm_config.ci_tcp_port, num);
return result;
}
/* Initialise SCTP socket and bind to all interfaces */
static int sctp_listen_for_all(void)
{
struct socket *sock = NULL;
struct sockaddr_storage localaddr;
struct sctp_event_subscribe subscribe;
int result = -EINVAL, num = 1, i, addr_len;
struct connection *con = nodeid2con(0, GFP_NOFS);
int bufsize = NEEDED_RMEM;
if (!con)
return -ENOMEM;
log_print("Using SCTP for communications");
result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_SEQPACKET,
IPPROTO_SCTP, &sock);
if (result < 0) {
log_print("Can't create comms socket, check SCTP is loaded");
goto out;
}
/* Listen for events */
memset(&subscribe, 0, sizeof(subscribe));
subscribe.sctp_data_io_event = 1;
subscribe.sctp_association_event = 1;
subscribe.sctp_send_failure_event = 1;
subscribe.sctp_shutdown_event = 1;
subscribe.sctp_partial_delivery_event = 1;
result = kernel_setsockopt(sock, SOL_SOCKET, SO_RCVBUFFORCE,
(char *)&bufsize, sizeof(bufsize));
if (result)
log_print("Error increasing buffer space on socket %d", result);
result = kernel_setsockopt(sock, SOL_SCTP, SCTP_EVENTS,
(char *)&subscribe, sizeof(subscribe));
if (result < 0) {
log_print("Failed to set SCTP_EVENTS on socket: result=%d",
result);
goto create_delsock;
}
/* Init con struct */
sock->sk->sk_user_data = con;
con->sock = sock;
con->sock->sk->sk_data_ready = lowcomms_data_ready;
con->rx_action = receive_from_sock;
con->connect_action = sctp_init_assoc;
/* Bind to all interfaces. */
for (i = 0; i < dlm_local_count; i++) {
memcpy(&localaddr, dlm_local_addr[i], sizeof(localaddr));
make_sockaddr(&localaddr, dlm_config.ci_tcp_port, &addr_len);
result = add_sctp_bind_addr(con, &localaddr, addr_len, num);
if (result)
goto create_delsock;
++num;
}
result = sock->ops->listen(sock, 5);
if (result < 0) {
log_print("Can't set socket listening");
goto create_delsock;
}
return 0;
create_delsock:
sock_release(sock);
con->sock = NULL;
out:
return result;
}
static int tcp_listen_for_all(void)
{
struct socket *sock = NULL;
struct connection *con = nodeid2con(0, GFP_NOFS);
int result = -EINVAL;
if (!con)
return -ENOMEM;
/* We don't support multi-homed hosts */
if (dlm_local_addr[1] != NULL) {
log_print("TCP protocol can't handle multi-homed hosts, "
"try SCTP");
return -EINVAL;
}
log_print("Using TCP for communications");
sock = tcp_create_listen_sock(con, dlm_local_addr[0]);
if (sock) {
add_sock(sock, con);
result = 0;
}
else {
result = -EADDRINUSE;
}
return result;
}
static struct writequeue_entry *new_writequeue_entry(struct connection *con,
gfp_t allocation)
{
struct writequeue_entry *entry;
entry = kmalloc(sizeof(struct writequeue_entry), allocation);
if (!entry)
return NULL;
entry->page = alloc_page(allocation);
if (!entry->page) {
kfree(entry);
return NULL;
}
entry->offset = 0;
entry->len = 0;
entry->end = 0;
entry->users = 0;
entry->con = con;
return entry;
}
void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
{
struct connection *con;
struct writequeue_entry *e;
int offset = 0;
int users = 0;
con = nodeid2con(nodeid, allocation);
if (!con)
return NULL;
spin_lock(&con->writequeue_lock);
e = list_entry(con->writequeue.prev, struct writequeue_entry, list);
if ((&e->list == &con->writequeue) ||
(PAGE_CACHE_SIZE - e->end < len)) {
e = NULL;
} else {
offset = e->end;
e->end += len;
users = e->users++;
}
spin_unlock(&con->writequeue_lock);
if (e) {
got_one:
*ppc = page_address(e->page) + offset;
return e;
}
e = new_writequeue_entry(con, allocation);
if (e) {
spin_lock(&con->writequeue_lock);
offset = e->end;
e->end += len;
users = e->users++;
list_add_tail(&e->list, &con->writequeue);
spin_unlock(&con->writequeue_lock);
goto got_one;
}
return NULL;
}
void dlm_lowcomms_commit_buffer(void *mh)
{
struct writequeue_entry *e = (struct writequeue_entry *)mh;
struct connection *con = e->con;
int users;
spin_lock(&con->writequeue_lock);
users = --e->users;
if (users)
goto out;
e->len = e->end - e->offset;
spin_unlock(&con->writequeue_lock);
if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags)) {
queue_work(send_workqueue, &con->swork);
}
return;
out:
spin_unlock(&con->writequeue_lock);
return;
}
/* Send a message */
static void send_to_sock(struct connection *con)
{
int ret = 0;
const int msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL;
struct writequeue_entry *e;
int len, offset;
mutex_lock(&con->sock_mutex);
if (con->sock == NULL)
goto out_connect;
spin_lock(&con->writequeue_lock);
for (;;) {
e = list_entry(con->writequeue.next, struct writequeue_entry,
list);
if ((struct list_head *) e == &con->writequeue)
break;
len = e->len;
offset = e->offset;
BUG_ON(len == 0 && e->users == 0);
spin_unlock(&con->writequeue_lock);
ret = 0;
if (len) {
ret = kernel_sendpage(con->sock, e->page, offset, len,
msg_flags);
if (ret == -EAGAIN || ret == 0) {
cond_resched();
goto out;
}
if (ret <= 0)
goto send_error;
}
/* Don't starve people filling buffers */
cond_resched();
spin_lock(&con->writequeue_lock);
e->offset += ret;
e->len -= ret;
if (e->len == 0 && e->users == 0) {
list_del(&e->list);
free_entry(e);
continue;
}
}
spin_unlock(&con->writequeue_lock);
out:
mutex_unlock(&con->sock_mutex);
return;
send_error:
mutex_unlock(&con->sock_mutex);
close_connection(con, false);
lowcomms_connect_sock(con);
return;
out_connect:
mutex_unlock(&con->sock_mutex);
if (!test_bit(CF_INIT_PENDING, &con->flags))
lowcomms_connect_sock(con);
return;
}
static void clean_one_writequeue(struct connection *con)
{
struct writequeue_entry *e, *safe;
spin_lock(&con->writequeue_lock);
list_for_each_entry_safe(e, safe, &con->writequeue, list) {
list_del(&e->list);
free_entry(e);
}
spin_unlock(&con->writequeue_lock);
}
/* Called from recovery when it knows that a node has
left the cluster */
int dlm_lowcomms_close(int nodeid)
{
struct connection *con;
log_print("closing connection to node %d", nodeid);
con = nodeid2con(nodeid, 0);
if (con) {
clear_bit(CF_CONNECT_PENDING, &con->flags);
clear_bit(CF_WRITE_PENDING, &con->flags);
set_bit(CF_CLOSE, &con->flags);
if (cancel_work_sync(&con->swork))
log_print("canceled swork for node %d", nodeid);
if (cancel_work_sync(&con->rwork))
log_print("canceled rwork for node %d", nodeid);
clean_one_writequeue(con);
close_connection(con, true);
}
return 0;
}
/* Receive workqueue function */
static void process_recv_sockets(struct work_struct *work)
{
struct connection *con = container_of(work, struct connection, rwork);
int err;
clear_bit(CF_READ_PENDING, &con->flags);
do {
err = con->rx_action(con);
} while (!err);
}
/* Send workqueue function */
static void process_send_sockets(struct work_struct *work)
{
struct connection *con = container_of(work, struct connection, swork);
if (test_and_clear_bit(CF_CONNECT_PENDING, &con->flags)) {
con->connect_action(con);
set_bit(CF_WRITE_PENDING, &con->flags);
}
if (test_and_clear_bit(CF_WRITE_PENDING, &con->flags))
send_to_sock(con);
}
/* Discard all entries on the write queues */
static void clean_writequeues(void)
{
foreach_conn(clean_one_writequeue);
}
static void work_stop(void)
{
destroy_workqueue(recv_workqueue);
destroy_workqueue(send_workqueue);
}
static int work_start(void)
{
int error;
recv_workqueue = create_workqueue("dlm_recv");
error = IS_ERR(recv_workqueue);
if (error) {
log_print("can't start dlm_recv %d", error);
return error;
}
send_workqueue = create_singlethread_workqueue("dlm_send");
error = IS_ERR(send_workqueue);
if (error) {
log_print("can't start dlm_send %d", error);
destroy_workqueue(recv_workqueue);
return error;
}
return 0;
}
static void stop_conn(struct connection *con)
{
con->flags |= 0x0F;
if (con->sock && con->sock->sk)
con->sock->sk->sk_user_data = NULL;
}
static void free_conn(struct connection *con)
{
close_connection(con, true);
if (con->othercon)
kmem_cache_free(con_cache, con->othercon);
hlist_del(&con->list);
kmem_cache_free(con_cache, con);
}
void dlm_lowcomms_stop(void)
{
/* Set all the flags to prevent any
socket activity.
*/
mutex_lock(&connections_lock);
foreach_conn(stop_conn);
mutex_unlock(&connections_lock);
work_stop();
mutex_lock(&connections_lock);
clean_writequeues();
foreach_conn(free_conn);
mutex_unlock(&connections_lock);
kmem_cache_destroy(con_cache);
}
int dlm_lowcomms_start(void)
{
int error = -EINVAL;
struct connection *con;
int i;
for (i = 0; i < CONN_HASH_SIZE; i++)
INIT_HLIST_HEAD(&connection_hash[i]);
init_local();
if (!dlm_local_count) {
error = -ENOTCONN;
log_print("no local IP address has been set");
goto out;
}
error = -ENOMEM;
con_cache = kmem_cache_create("dlm_conn", sizeof(struct connection),
__alignof__(struct connection), 0,
NULL);
if (!con_cache)
goto out;
/* Start listening */
if (dlm_config.ci_protocol == 0)
error = tcp_listen_for_all();
else
error = sctp_listen_for_all();
if (error)
goto fail_unlisten;
error = work_start();
if (error)
goto fail_unlisten;
return 0;
fail_unlisten:
con = nodeid2con(0,0);
if (con) {
close_connection(con, false);
kmem_cache_free(con_cache, con);
}
kmem_cache_destroy(con_cache);
out:
return error;
}