#include <linux/ceph/ceph_debug.h>

  #include <linux/module.h>

  #include <linux/types.h>

  #include <linux/slab.h>

  #include <linux/random.h>
  #include <linux/sched.h>

  #include <linux/ceph/mon_client.h>
  #include <linux/ceph/libceph.h>
  #include <linux/ceph/decode.h>
  
  #include <linux/ceph/auth.h>

  
  /*
   * Interact with Ceph monitor cluster.  Handle requests for new map
   * versions, and periodically resend as needed.  Also implement
   * statfs() and umount().
   *
   * A small cluster of Ceph "monitors" are responsible for managing critical
   * cluster configuration and state information.  An odd number (e.g., 3, 5)
   * of cmon daemons use a modified version of the Paxos part-time parliament
   * algorithm to manage the MDS map (mds cluster membership), OSD map, and
   * list of clients who have mounted the file system.
   *
   * We maintain an open, active session with a monitor at all times in order to
   * receive timely MDSMap updates.  We periodically send a keepalive byte on the
   * TCP socket to ensure we detect a failure.  If the connection does break, we
   * randomly hunt for a new monitor.  Once the connection is reestablished, we
   * resend any outstanding requests.
   */

  static const struct ceph_connection_operations mon_con_ops;

  static int __validate_auth(struct ceph_mon_client *monc);

  /*
   * Decode a monmap blob (e.g., during mount).
   */
  struct ceph_monmap *ceph_monmap_decode(void *p, void *end)
  {
  	struct ceph_monmap *m = NULL;
  	int i, err = -EINVAL;
  	struct ceph_fsid fsid;
  	u32 epoch, num_mon;
  	u16 version;

  	u32 len;
  
  	ceph_decode_32_safe(&p, end, len, bad);
  	ceph_decode_need(&p, end, len, bad);

  
  	dout("monmap_decode %p %p len %d
  ", p, end, (int)(end-p));
  
  	ceph_decode_16_safe(&p, end, version, bad);
  
  	ceph_decode_need(&p, end, sizeof(fsid) + 2*sizeof(u32), bad);
  	ceph_decode_copy(&p, &fsid, sizeof(fsid));

  	epoch = ceph_decode_32(&p);

  	num_mon = ceph_decode_32(&p);

  	ceph_decode_need(&p, end, num_mon*sizeof(m->mon_inst[0]), bad);
  
  	if (num_mon >= CEPH_MAX_MON)
  		goto bad;
  	m = kmalloc(sizeof(*m) + sizeof(m->mon_inst[0])*num_mon, GFP_NOFS);
  	if (m == NULL)
  		return ERR_PTR(-ENOMEM);
  	m->fsid = fsid;
  	m->epoch = epoch;
  	m->num_mon = num_mon;
  	ceph_decode_copy(&p, m->mon_inst, num_mon*sizeof(m->mon_inst[0]));

  	for (i = 0; i < num_mon; i++)
  		ceph_decode_addr(&m->mon_inst[i].addr);

  	dout("monmap_decode epoch %d, num_mon %d
  ", m->epoch,
  	     m->num_mon);
  	for (i = 0; i < m->num_mon; i++)
  		dout("monmap_decode  mon%d is %s
  ", i,

  		     ceph_pr_addr(&m->mon_inst[i].addr.in_addr));

  	return m;
  
  bad:
  	dout("monmap_decode failed with %d
  ", err);
  	kfree(m);
  	return ERR_PTR(err);
  }
  
  /*
   * return true if *addr is included in the monmap.
   */
  int ceph_monmap_contains(struct ceph_monmap *m, struct ceph_entity_addr *addr)
  {
  	int i;
  
  	for (i = 0; i < m->num_mon; i++)

  		if (memcmp(addr, &m->mon_inst[i].addr, sizeof(*addr)) == 0)

  			return 1;
  	return 0;
  }
  
  /*

   * Send an auth request.
   */
  static void __send_prepared_auth_request(struct ceph_mon_client *monc, int len)
  {
  	monc->pending_auth = 1;
  	monc->m_auth->front.iov_len = len;
  	monc->m_auth->hdr.front_len = cpu_to_le32(len);

  	ceph_con_revoke(monc->con, monc->m_auth);

  	ceph_msg_get(monc->m_auth);  /* keep our ref */
  	ceph_con_send(monc->con, monc->m_auth);
  }
  
  /*

   * Close monitor session, if any.
   */
  static void __close_session(struct ceph_mon_client *monc)
  {

  	dout("__close_session closing mon%d
  ", monc->cur_mon);
  	ceph_con_revoke(monc->con, monc->m_auth);
  	ceph_con_close(monc->con);
  	monc->cur_mon = -1;
  	monc->pending_auth = 0;
  	ceph_auth_reset(monc->auth);

  }
  
  /*
   * Open a session with a (new) monitor.
   */
  static int __open_session(struct ceph_mon_client *monc)
  {
  	char r;

  	int ret;

  
  	if (monc->cur_mon < 0) {
  		get_random_bytes(&r, 1);
  		monc->cur_mon = r % monc->monmap->num_mon;
  		dout("open_session num=%d r=%d -> mon%d
  ",
  		     monc->monmap->num_mon, r, monc->cur_mon);
  		monc->sub_sent = 0;
  		monc->sub_renew_after = jiffies;  /* i.e., expired */
  		monc->want_next_osdmap = !!monc->want_next_osdmap;
  
  		dout("open_session mon%d opening
  ", monc->cur_mon);
  		monc->con->peer_name.type = CEPH_ENTITY_TYPE_MON;
  		monc->con->peer_name.num = cpu_to_le64(monc->cur_mon);
  		ceph_con_open(monc->con,
  			      &monc->monmap->mon_inst[monc->cur_mon].addr);

  
  		/* initiatiate authentication handshake */
  		ret = ceph_auth_build_hello(monc->auth,
  					    monc->m_auth->front.iov_base,
  					    monc->m_auth->front_max);

  		__send_prepared_auth_request(monc, ret);

  	} else {
  		dout("open_session mon%d already open
  ", monc->cur_mon);
  	}
  	return 0;
  }
  
  static bool __sub_expired(struct ceph_mon_client *monc)
  {
  	return time_after_eq(jiffies, monc->sub_renew_after);
  }
  
  /*
   * Reschedule delayed work timer.
   */
  static void __schedule_delayed(struct ceph_mon_client *monc)
  {
  	unsigned delay;

  	if (monc->cur_mon < 0 || __sub_expired(monc))

  		delay = 10 * HZ;
  	else
  		delay = 20 * HZ;
  	dout("__schedule_delayed after %u
  ", delay);
  	schedule_delayed_work(&monc->delayed_work, delay);
  }
  
  /*
   * Send subscribe request for mdsmap and/or osdmap.
   */
  static void __send_subscribe(struct ceph_mon_client *monc)
  {
  	dout("__send_subscribe sub_sent=%u exp=%u want_osd=%d
  ",
  	     (unsigned)monc->sub_sent, __sub_expired(monc),
  	     monc->want_next_osdmap);
  	if ((__sub_expired(monc) && !monc->sub_sent) ||
  	    monc->want_next_osdmap == 1) {

  		struct ceph_msg *msg = monc->m_subscribe;

  		struct ceph_mon_subscribe_item *i;
  		void *p, *end;

  		int num;

  		p = msg->front.iov_base;

  		end = p + msg->front_max;

  		num = 1 + !!monc->want_next_osdmap + !!monc->want_mdsmap;
  		ceph_encode_32(&p, num);

  		if (monc->want_next_osdmap) {
  			dout("__send_subscribe to 'osdmap' %u
  ",
  			     (unsigned)monc->have_osdmap);

  			ceph_encode_string(&p, end, "osdmap", 6);
  			i = p;
  			i->have = cpu_to_le64(monc->have_osdmap);
  			i->onetime = 1;
  			p += sizeof(*i);
  			monc->want_next_osdmap = 2;  /* requested */

  		}

  		if (monc->want_mdsmap) {
  			dout("__send_subscribe to 'mdsmap' %u+
  ",
  			     (unsigned)monc->have_mdsmap);
  			ceph_encode_string(&p, end, "mdsmap", 6);
  			i = p;
  			i->have = cpu_to_le64(monc->have_mdsmap);
  			i->onetime = 0;
  			p += sizeof(*i);
  		}

  		ceph_encode_string(&p, end, "monmap", 6);
  		i = p;
  		i->have = 0;
  		i->onetime = 0;
  		p += sizeof(*i);

  
  		msg->front.iov_len = p - msg->front.iov_base;
  		msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);

  		ceph_con_revoke(monc->con, msg);
  		ceph_con_send(monc->con, ceph_msg_get(msg));

  
  		monc->sub_sent = jiffies | 1;  /* never 0 */
  	}
  }
  
  static void handle_subscribe_ack(struct ceph_mon_client *monc,
  				 struct ceph_msg *msg)
  {
  	unsigned seconds;

  	struct ceph_mon_subscribe_ack *h = msg->front.iov_base;
  
  	if (msg->front.iov_len < sizeof(*h))
  		goto bad;
  	seconds = le32_to_cpu(h->duration);

  	mutex_lock(&monc->mutex);
  	if (monc->hunting) {
  		pr_info("mon%d %s session established
  ",

  			monc->cur_mon,
  			ceph_pr_addr(&monc->con->peer_addr.in_addr));

  		monc->hunting = false;
  	}
  	dout("handle_subscribe_ack after %d seconds
  ", seconds);

  	monc->sub_renew_after = monc->sub_sent + (seconds >> 1)*HZ - 1;

  	monc->sub_sent = 0;
  	mutex_unlock(&monc->mutex);
  	return;
  bad:
  	pr_err("got corrupt subscribe-ack msg
  ");

  	ceph_msg_dump(msg);

  }
  
  /*
   * Keep track of which maps we have
   */
  int ceph_monc_got_mdsmap(struct ceph_mon_client *monc, u32 got)
  {
  	mutex_lock(&monc->mutex);
  	monc->have_mdsmap = got;
  	mutex_unlock(&monc->mutex);
  	return 0;
  }

  EXPORT_SYMBOL(ceph_monc_got_mdsmap);

  
  int ceph_monc_got_osdmap(struct ceph_mon_client *monc, u32 got)
  {
  	mutex_lock(&monc->mutex);
  	monc->have_osdmap = got;
  	monc->want_next_osdmap = 0;
  	mutex_unlock(&monc->mutex);
  	return 0;
  }
  
  /*
   * Register interest in the next osdmap
   */
  void ceph_monc_request_next_osdmap(struct ceph_mon_client *monc)
  {
  	dout("request_next_osdmap have %u
  ", monc->have_osdmap);
  	mutex_lock(&monc->mutex);
  	if (!monc->want_next_osdmap)
  		monc->want_next_osdmap = 1;
  	if (monc->want_next_osdmap < 2)
  		__send_subscribe(monc);
  	mutex_unlock(&monc->mutex);
  }

  /*

   *

   */
  int ceph_monc_open_session(struct ceph_mon_client *monc)

  {

  	mutex_lock(&monc->mutex);

  	__open_session(monc);

  	__schedule_delayed(monc);
  	mutex_unlock(&monc->mutex);
  	return 0;
  }

  EXPORT_SYMBOL(ceph_monc_open_session);

  /*
   * The monitor responds with mount ack indicate mount success.  The
   * included client ticket allows the client to talk to MDSs and OSDs.
   */

  static void ceph_monc_handle_map(struct ceph_mon_client *monc,
  				 struct ceph_msg *msg)

  {
  	struct ceph_client *client = monc->client;
  	struct ceph_monmap *monmap = NULL, *old = monc->monmap;
  	void *p, *end;
  
  	mutex_lock(&monc->mutex);
  
  	dout("handle_monmap
  ");
  	p = msg->front.iov_base;
  	end = p + msg->front.iov_len;
  
  	monmap = ceph_monmap_decode(p, end);
  	if (IS_ERR(monmap)) {
  		pr_err("problem decoding monmap, %d
  ",
  		       (int)PTR_ERR(monmap));

  		goto out;

  	}

  
  	if (ceph_check_fsid(monc->client, &monmap->fsid) < 0) {

  		kfree(monmap);

  		goto out;

  	}
  
  	client->monc.monmap = monmap;

  	kfree(old);

  out:

  	mutex_unlock(&monc->mutex);

  	wake_up_all(&client->auth_wq);

  }

  /*

   * generic requests (e.g., statfs, poolop)

   */

  static struct ceph_mon_generic_request *__lookup_generic_req(

  	struct ceph_mon_client *monc, u64 tid)
  {

  	struct ceph_mon_generic_request *req;
  	struct rb_node *n = monc->generic_request_tree.rb_node;

  
  	while (n) {

  		req = rb_entry(n, struct ceph_mon_generic_request, node);

  		if (tid < req->tid)
  			n = n->rb_left;
  		else if (tid > req->tid)
  			n = n->rb_right;
  		else
  			return req;
  	}
  	return NULL;
  }

  static void __insert_generic_request(struct ceph_mon_client *monc,
  			    struct ceph_mon_generic_request *new)

  {

  	struct rb_node **p = &monc->generic_request_tree.rb_node;

  	struct rb_node *parent = NULL;

  	struct ceph_mon_generic_request *req = NULL;

  
  	while (*p) {
  		parent = *p;

  		req = rb_entry(parent, struct ceph_mon_generic_request, node);

  		if (new->tid < req->tid)
  			p = &(*p)->rb_left;
  		else if (new->tid > req->tid)
  			p = &(*p)->rb_right;
  		else
  			BUG();
  	}
  
  	rb_link_node(&new->node, parent, p);

  	rb_insert_color(&new->node, &monc->generic_request_tree);

  }

  static void release_generic_request(struct kref *kref)

  {

  	struct ceph_mon_generic_request *req =
  		container_of(kref, struct ceph_mon_generic_request, kref);

  
  	if (req->reply)
  		ceph_msg_put(req->reply);
  	if (req->request)
  		ceph_msg_put(req->request);

  
  	kfree(req);

  }

  static void put_generic_request(struct ceph_mon_generic_request *req)

  {

  	kref_put(&req->kref, release_generic_request);

  }

  static void get_generic_request(struct ceph_mon_generic_request *req)

  {
  	kref_get(&req->kref);
  }

  static struct ceph_msg *get_generic_reply(struct ceph_connection *con,

  					 struct ceph_msg_header *hdr,
  					 int *skip)
  {
  	struct ceph_mon_client *monc = con->private;

  	struct ceph_mon_generic_request *req;

  	u64 tid = le64_to_cpu(hdr->tid);
  	struct ceph_msg *m;
  
  	mutex_lock(&monc->mutex);

  	req = __lookup_generic_req(monc, tid);

  	if (!req) {

  		dout("get_generic_reply %lld dne
  ", tid);

  		*skip = 1;
  		m = NULL;
  	} else {

  		dout("get_generic_reply %lld got %p
  ", tid, req->reply);

  		m = ceph_msg_get(req->reply);
  		/*
  		 * we don't need to track the connection reading into
  		 * this reply because we only have one open connection
  		 * at a time, ever.
  		 */
  	}
  	mutex_unlock(&monc->mutex);
  	return m;
  }

  static int do_generic_request(struct ceph_mon_client *monc,
  			      struct ceph_mon_generic_request *req)
  {
  	int err;
  
  	/* register request */
  	mutex_lock(&monc->mutex);
  	req->tid = ++monc->last_tid;
  	req->request->hdr.tid = cpu_to_le64(req->tid);
  	__insert_generic_request(monc, req);
  	monc->num_generic_requests++;
  	ceph_con_send(monc->con, ceph_msg_get(req->request));
  	mutex_unlock(&monc->mutex);
  
  	err = wait_for_completion_interruptible(&req->completion);
  
  	mutex_lock(&monc->mutex);
  	rb_erase(&req->node, &monc->generic_request_tree);
  	monc->num_generic_requests--;
  	mutex_unlock(&monc->mutex);
  
  	if (!err)
  		err = req->result;
  	return err;
  }
  
  /*
   * statfs
   */

  static void handle_statfs_reply(struct ceph_mon_client *monc,
  				struct ceph_msg *msg)
  {

  	struct ceph_mon_generic_request *req;

  	struct ceph_mon_statfs_reply *reply = msg->front.iov_base;

  	u64 tid = le64_to_cpu(msg->hdr.tid);

  
  	if (msg->front.iov_len != sizeof(*reply))
  		goto bad;

  	dout("handle_statfs_reply %p tid %llu
  ", msg, tid);
  
  	mutex_lock(&monc->mutex);

  	req = __lookup_generic_req(monc, tid);

  	if (req) {

  		*(struct ceph_statfs *)req->buf = reply->st;

  		req->result = 0;

  		get_generic_request(req);

  	}
  	mutex_unlock(&monc->mutex);

  	if (req) {

  		complete_all(&req->completion);

  		put_generic_request(req);

  	}

  	return;
  
  bad:

  	pr_err("corrupt generic reply, tid %llu
  ", tid);

  	ceph_msg_dump(msg);

  }
  
  /*

   * Do a synchronous statfs().

   */

  int ceph_monc_do_statfs(struct ceph_mon_client *monc, struct ceph_statfs *buf)

  {

  	struct ceph_mon_generic_request *req;

  	struct ceph_mon_statfs *h;

  	int err;

  	req = kzalloc(sizeof(*req), GFP_NOFS);

  	if (!req)
  		return -ENOMEM;

  	kref_init(&req->kref);
  	req->buf = buf;

  	req->buf_len = sizeof(*buf);

  	init_completion(&req->completion);

  	err = -ENOMEM;

  	req->request = ceph_msg_new(CEPH_MSG_STATFS, sizeof(*h), GFP_NOFS,
  				    true);

  	if (!req->request)

  		goto out;

  	req->reply = ceph_msg_new(CEPH_MSG_STATFS_REPLY, 1024, GFP_NOFS,
  				  true);

  	if (!req->reply)

  		goto out;

  
  	/* fill out request */
  	h = req->request->front.iov_base;

  	h->monhdr.have_version = 0;
  	h->monhdr.session_mon = cpu_to_le16(-1);
  	h->monhdr.session_mon_tid = 0;

  	h->fsid = monc->monmap->fsid;

  	err = do_generic_request(monc, req);

  out:
  	kref_put(&req->kref, release_generic_request);
  	return err;
  }

  EXPORT_SYMBOL(ceph_monc_do_statfs);

  
  /*
   * pool ops
   */
  static int get_poolop_reply_buf(const char *src, size_t src_len,
  				char *dst, size_t dst_len)
  {
  	u32 buf_len;
  
  	if (src_len != sizeof(u32) + dst_len)
  		return -EINVAL;
  
  	buf_len = le32_to_cpu(*(u32 *)src);
  	if (buf_len != dst_len)
  		return -EINVAL;
  
  	memcpy(dst, src + sizeof(u32), dst_len);
  	return 0;
  }
  
  static void handle_poolop_reply(struct ceph_mon_client *monc,
  				struct ceph_msg *msg)
  {
  	struct ceph_mon_generic_request *req;
  	struct ceph_mon_poolop_reply *reply = msg->front.iov_base;
  	u64 tid = le64_to_cpu(msg->hdr.tid);
  
  	if (msg->front.iov_len < sizeof(*reply))
  		goto bad;
  	dout("handle_poolop_reply %p tid %llu
  ", msg, tid);

  
  	mutex_lock(&monc->mutex);

  	req = __lookup_generic_req(monc, tid);
  	if (req) {
  		if (req->buf_len &&
  		    get_poolop_reply_buf(msg->front.iov_base + sizeof(*reply),
  				     msg->front.iov_len - sizeof(*reply),
  				     req->buf, req->buf_len) < 0) {
  			mutex_unlock(&monc->mutex);
  			goto bad;
  		}
  		req->result = le32_to_cpu(reply->reply_code);
  		get_generic_request(req);
  	}

  	mutex_unlock(&monc->mutex);

  	if (req) {
  		complete(&req->completion);
  		put_generic_request(req);
  	}
  	return;

  bad:
  	pr_err("corrupt generic reply, tid %llu
  ", tid);
  	ceph_msg_dump(msg);
  }
  
  /*
   * Do a synchronous pool op.
   */
  int ceph_monc_do_poolop(struct ceph_mon_client *monc, u32 op,
  			u32 pool, u64 snapid,
  			char *buf, int len)
  {
  	struct ceph_mon_generic_request *req;
  	struct ceph_mon_poolop *h;
  	int err;
  
  	req = kzalloc(sizeof(*req), GFP_NOFS);
  	if (!req)
  		return -ENOMEM;
  
  	kref_init(&req->kref);
  	req->buf = buf;
  	req->buf_len = len;
  	init_completion(&req->completion);
  
  	err = -ENOMEM;

  	req->request = ceph_msg_new(CEPH_MSG_POOLOP, sizeof(*h), GFP_NOFS,
  				    true);

  	if (!req->request)
  		goto out;

  	req->reply = ceph_msg_new(CEPH_MSG_POOLOP_REPLY, 1024, GFP_NOFS,
  				  true);

  	if (!req->reply)
  		goto out;
  
  	/* fill out request */
  	req->request->hdr.version = cpu_to_le16(2);
  	h = req->request->front.iov_base;
  	h->monhdr.have_version = 0;
  	h->monhdr.session_mon = cpu_to_le16(-1);
  	h->monhdr.session_mon_tid = 0;
  	h->fsid = monc->monmap->fsid;
  	h->pool = cpu_to_le32(pool);
  	h->op = cpu_to_le32(op);
  	h->auid = 0;
  	h->snapid = cpu_to_le64(snapid);
  	h->name_len = 0;
  
  	err = do_generic_request(monc, req);

  
  out:

  	kref_put(&req->kref, release_generic_request);

  	return err;
  }

  int ceph_monc_create_snapid(struct ceph_mon_client *monc,
  			    u32 pool, u64 *snapid)
  {
  	return ceph_monc_do_poolop(monc,  POOL_OP_CREATE_UNMANAGED_SNAP,
  				   pool, 0, (char *)snapid, sizeof(*snapid));
  
  }

  EXPORT_SYMBOL(ceph_monc_create_snapid);

  
  int ceph_monc_delete_snapid(struct ceph_mon_client *monc,
  			    u32 pool, u64 snapid)
  {
  	return ceph_monc_do_poolop(monc,  POOL_OP_CREATE_UNMANAGED_SNAP,
  				   pool, snapid, 0, 0);
  
  }

  /*

   * Resend pending generic requests.

   */

  static void __resend_generic_request(struct ceph_mon_client *monc)

  {

  	struct ceph_mon_generic_request *req;

  	struct rb_node *p;

  	for (p = rb_first(&monc->generic_request_tree); p; p = rb_next(p)) {
  		req = rb_entry(p, struct ceph_mon_generic_request, node);

  		ceph_con_revoke(monc->con, req->request);

  		ceph_con_send(monc->con, ceph_msg_get(req->request));

  	}
  }
  
  /*
   * Delayed work.  If we haven't mounted yet, retry.  Otherwise,
   * renew/retry subscription as needed (in case it is timing out, or we
   * got an ENOMEM).  And keep the monitor connection alive.
   */
  static void delayed_work(struct work_struct *work)
  {
  	struct ceph_mon_client *monc =
  		container_of(work, struct ceph_mon_client, delayed_work.work);
  
  	dout("monc delayed_work
  ");
  	mutex_lock(&monc->mutex);

  	if (monc->hunting) {
  		__close_session(monc);
  		__open_session(monc);  /* continue hunting */

  	} else {

  		ceph_con_keepalive(monc->con);

  
  		__validate_auth(monc);

  		if (monc->auth->ops->is_authenticated(monc->auth))
  			__send_subscribe(monc);

  	}

  	__schedule_delayed(monc);
  	mutex_unlock(&monc->mutex);
  }

  /*
   * On startup, we build a temporary monmap populated with the IPs
   * provided by mount(2).
   */
  static int build_initial_monmap(struct ceph_mon_client *monc)
  {

  	struct ceph_options *opt = monc->client->options;
  	struct ceph_entity_addr *mon_addr = opt->mon_addr;
  	int num_mon = opt->num_mon;

  	int i;
  
  	/* build initial monmap */
  	monc->monmap = kzalloc(sizeof(*monc->monmap) +
  			       num_mon*sizeof(monc->monmap->mon_inst[0]),
  			       GFP_KERNEL);
  	if (!monc->monmap)
  		return -ENOMEM;
  	for (i = 0; i < num_mon; i++) {
  		monc->monmap->mon_inst[i].addr = mon_addr[i];

  		monc->monmap->mon_inst[i].addr.nonce = 0;
  		monc->monmap->mon_inst[i].name.type =
  			CEPH_ENTITY_TYPE_MON;
  		monc->monmap->mon_inst[i].name.num = cpu_to_le64(i);
  	}
  	monc->monmap->num_mon = num_mon;

  	monc->have_fsid = false;

  	return 0;
  }

  int ceph_monc_init(struct ceph_mon_client *monc, struct ceph_client *cl)
  {
  	int err = 0;
  
  	dout("init
  ");
  	memset(monc, 0, sizeof(*monc));
  	monc->client = cl;
  	monc->monmap = NULL;
  	mutex_init(&monc->mutex);

  	err = build_initial_monmap(monc);
  	if (err)
  		goto out;

  	/* connection */
  	monc->con = kmalloc(sizeof(*monc->con), GFP_KERNEL);
  	if (!monc->con)
  		goto out_monmap;
  	ceph_con_init(monc->client->msgr, monc->con);
  	monc->con->private = monc;
  	monc->con->ops = &mon_con_ops;

  	/* authentication */

  	monc->auth = ceph_auth_init(cl->options->name,

  				    cl->options->key);

  	if (IS_ERR(monc->auth)) {
  		err = PTR_ERR(monc->auth);
  		goto out_con;
  	}

  	monc->auth->want_keys =
  		CEPH_ENTITY_TYPE_AUTH | CEPH_ENTITY_TYPE_MON |
  		CEPH_ENTITY_TYPE_OSD | CEPH_ENTITY_TYPE_MDS;

  	/* msgs */

  	err = -ENOMEM;

  	monc->m_subscribe_ack = ceph_msg_new(CEPH_MSG_MON_SUBSCRIBE_ACK,

  				     sizeof(struct ceph_mon_subscribe_ack),

  				     GFP_NOFS, true);

  	if (!monc->m_subscribe_ack)

  		goto out_auth;

  	monc->m_subscribe = ceph_msg_new(CEPH_MSG_MON_SUBSCRIBE, 96, GFP_NOFS,
  					 true);

  	if (!monc->m_subscribe)
  		goto out_subscribe_ack;

  	monc->m_auth_reply = ceph_msg_new(CEPH_MSG_AUTH_REPLY, 4096, GFP_NOFS,
  					  true);

  	if (!monc->m_auth_reply)

  		goto out_subscribe;

  	monc->m_auth = ceph_msg_new(CEPH_MSG_AUTH, 4096, GFP_NOFS, true);

  	monc->pending_auth = 0;

  	if (!monc->m_auth)

  		goto out_auth_reply;

  
  	monc->cur_mon = -1;

  	monc->hunting = true;

  	monc->sub_renew_after = jiffies;
  	monc->sub_sent = 0;
  
  	INIT_DELAYED_WORK(&monc->delayed_work, delayed_work);

  	monc->generic_request_tree = RB_ROOT;
  	monc->num_generic_requests = 0;

  	monc->last_tid = 0;
  
  	monc->have_mdsmap = 0;
  	monc->have_osdmap = 0;
  	monc->want_next_osdmap = 1;

  	return 0;

  out_auth_reply:
  	ceph_msg_put(monc->m_auth_reply);

  out_subscribe:
  	ceph_msg_put(monc->m_subscribe);

  out_subscribe_ack:
  	ceph_msg_put(monc->m_subscribe_ack);

  out_auth:
  	ceph_auth_destroy(monc->auth);

  out_con:
  	monc->con->ops->put(monc->con);

  out_monmap:
  	kfree(monc->monmap);

  out:
  	return err;
  }

  EXPORT_SYMBOL(ceph_monc_init);

  
  void ceph_monc_stop(struct ceph_mon_client *monc)
  {
  	dout("stop
  ");
  	cancel_delayed_work_sync(&monc->delayed_work);
  
  	mutex_lock(&monc->mutex);
  	__close_session(monc);

  
  	monc->con->private = NULL;
  	monc->con->ops->put(monc->con);
  	monc->con = NULL;

  	mutex_unlock(&monc->mutex);

  	ceph_auth_destroy(monc->auth);
  
  	ceph_msg_put(monc->m_auth);

  	ceph_msg_put(monc->m_auth_reply);

  	ceph_msg_put(monc->m_subscribe);

  	ceph_msg_put(monc->m_subscribe_ack);

  
  	kfree(monc->monmap);
  }

  EXPORT_SYMBOL(ceph_monc_stop);

  static void handle_auth_reply(struct ceph_mon_client *monc,
  			      struct ceph_msg *msg)
  {
  	int ret;

  	int was_auth = 0;

  
  	mutex_lock(&monc->mutex);

  	if (monc->auth->ops)
  		was_auth = monc->auth->ops->is_authenticated(monc->auth);

  	monc->pending_auth = 0;

  	ret = ceph_handle_auth_reply(monc->auth, msg->front.iov_base,
  				     msg->front.iov_len,
  				     monc->m_auth->front.iov_base,
  				     monc->m_auth->front_max);
  	if (ret < 0) {

  		monc->client->auth_err = ret;

  		wake_up_all(&monc->client->auth_wq);

  	} else if (ret > 0) {

  		__send_prepared_auth_request(monc, ret);

  	} else if (!was_auth && monc->auth->ops->is_authenticated(monc->auth)) {

  		dout("authenticated, starting session
  ");

  
  		monc->client->msgr->inst.name.type = CEPH_ENTITY_TYPE_CLIENT;

  		monc->client->msgr->inst.name.num =
  					cpu_to_le64(monc->auth->global_id);

  		__send_subscribe(monc);

  		__resend_generic_request(monc);

  	}
  	mutex_unlock(&monc->mutex);
  }

  static int __validate_auth(struct ceph_mon_client *monc)
  {
  	int ret;
  
  	if (monc->pending_auth)
  		return 0;
  
  	ret = ceph_build_auth(monc->auth, monc->m_auth->front.iov_base,
  			      monc->m_auth->front_max);
  	if (ret <= 0)
  		return ret; /* either an error, or no need to authenticate */
  	__send_prepared_auth_request(monc, ret);
  	return 0;
  }
  
  int ceph_monc_validate_auth(struct ceph_mon_client *monc)
  {
  	int ret;
  
  	mutex_lock(&monc->mutex);
  	ret = __validate_auth(monc);
  	mutex_unlock(&monc->mutex);
  	return ret;
  }

  EXPORT_SYMBOL(ceph_monc_validate_auth);

  /*
   * handle incoming message
   */
  static void dispatch(struct ceph_connection *con, struct ceph_msg *msg)
  {
  	struct ceph_mon_client *monc = con->private;
  	int type = le16_to_cpu(msg->hdr.type);
  
  	if (!monc)
  		return;
  
  	switch (type) {

  	case CEPH_MSG_AUTH_REPLY:
  		handle_auth_reply(monc, msg);

  		break;
  
  	case CEPH_MSG_MON_SUBSCRIBE_ACK:
  		handle_subscribe_ack(monc, msg);
  		break;
  
  	case CEPH_MSG_STATFS_REPLY:
  		handle_statfs_reply(monc, msg);
  		break;

  	case CEPH_MSG_POOLOP_REPLY:
  		handle_poolop_reply(monc, msg);
  		break;

  	case CEPH_MSG_MON_MAP:
  		ceph_monc_handle_map(monc, msg);
  		break;

  	case CEPH_MSG_OSD_MAP:
  		ceph_osdc_handle_map(&monc->client->osdc, msg);
  		break;
  
  	default:

  		/* can the chained handler handle it? */
  		if (monc->client->extra_mon_dispatch &&
  		    monc->client->extra_mon_dispatch(monc->client, msg) == 0)
  			break;
  			

  		pr_err("received unknown message type %d %s
  ", type,
  		       ceph_msg_type_name(type));
  	}
  	ceph_msg_put(msg);
  }
  
  /*
   * Allocate memory for incoming message
   */
  static struct ceph_msg *mon_alloc_msg(struct ceph_connection *con,

  				      struct ceph_msg_header *hdr,
  				      int *skip)

  {
  	struct ceph_mon_client *monc = con->private;
  	int type = le16_to_cpu(hdr->type);

  	int front_len = le32_to_cpu(hdr->front_len);

  	struct ceph_msg *m = NULL;

  	*skip = 0;

  	switch (type) {

  	case CEPH_MSG_MON_SUBSCRIBE_ACK:

  		m = ceph_msg_get(monc->m_subscribe_ack);

  		break;

  	case CEPH_MSG_POOLOP_REPLY:

  	case CEPH_MSG_STATFS_REPLY:

  		return get_generic_reply(con, hdr, skip);

  	case CEPH_MSG_AUTH_REPLY:

  		m = ceph_msg_get(monc->m_auth_reply);

  		break;

  	case CEPH_MSG_MON_MAP:
  	case CEPH_MSG_MDS_MAP:
  	case CEPH_MSG_OSD_MAP:

  		m = ceph_msg_new(type, front_len, GFP_NOFS, false);

  		break;

  	}

  	if (!m) {
  		pr_info("alloc_msg unknown type %d
  ", type);

  		*skip = 1;

  	}

  	return m;

  }
  
  /*
   * If the monitor connection resets, pick a new monitor and resubmit
   * any pending requests.
   */
  static void mon_fault(struct ceph_connection *con)
  {
  	struct ceph_mon_client *monc = con->private;
  
  	if (!monc)
  		return;
  
  	dout("mon_fault
  ");
  	mutex_lock(&monc->mutex);
  	if (!con->private)
  		goto out;

  	if (!monc->hunting)

  		pr_info("mon%d %s session lost, "
  			"hunting for new mon
  ", monc->cur_mon,

  			ceph_pr_addr(&monc->con->peer_addr.in_addr));

  
  	__close_session(monc);
  	if (!monc->hunting) {
  		/* start hunting */
  		monc->hunting = true;

  		__open_session(monc);

  	} else {
  		/* already hunting, let's wait a bit */
  		__schedule_delayed(monc);
  	}
  out:
  	mutex_unlock(&monc->mutex);
  }

  static const struct ceph_connection_operations mon_con_ops = {

  	.get = ceph_con_get,
  	.put = ceph_con_put,
  	.dispatch = dispatch,
  	.fault = mon_fault,
  	.alloc_msg = mon_alloc_msg,

  };