/******************************************************************************
  *******************************************************************************
  **
  **  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.

  **  Copyright (C) 2005-2008 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.
  **
  *******************************************************************************
  ******************************************************************************/
  
  #include "dlm_internal.h"
  #include "lockspace.h"
  #include "member.h"
  #include "lowcomms.h"
  #include "midcomms.h"
  #include "rcom.h"
  #include "recover.h"
  #include "dir.h"
  #include "config.h"
  #include "memory.h"
  #include "lock.h"
  #include "util.h"
  
  
  static int rcom_response(struct dlm_ls *ls)
  {
  	return test_bit(LSFL_RCOM_READY, &ls->ls_flags);
  }
  
  static int create_rcom(struct dlm_ls *ls, int to_nodeid, int type, int len,
  		       struct dlm_rcom **rc_ret, struct dlm_mhandle **mh_ret)
  {
  	struct dlm_rcom *rc;
  	struct dlm_mhandle *mh;
  	char *mb;
  	int mb_len = sizeof(struct dlm_rcom) + len;

  	mh = dlm_lowcomms_get_buffer(to_nodeid, mb_len, GFP_NOFS, &mb);

  	if (!mh) {
  		log_print("create_rcom to %d type %d len %d ENOBUFS",
  			  to_nodeid, type, len);
  		return -ENOBUFS;
  	}
  	memset(mb, 0, mb_len);
  
  	rc = (struct dlm_rcom *) mb;
  
  	rc->rc_header.h_version = (DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
  	rc->rc_header.h_lockspace = ls->ls_global_id;
  	rc->rc_header.h_nodeid = dlm_our_nodeid();
  	rc->rc_header.h_length = mb_len;
  	rc->rc_header.h_cmd = DLM_RCOM;
  
  	rc->rc_type = type;

  	spin_lock(&ls->ls_recover_lock);
  	rc->rc_seq = ls->ls_recover_seq;
  	spin_unlock(&ls->ls_recover_lock);

  	*mh_ret = mh;
  	*rc_ret = rc;
  	return 0;
  }
  
  static void send_rcom(struct dlm_ls *ls, struct dlm_mhandle *mh,
  		      struct dlm_rcom *rc)
  {
  	dlm_rcom_out(rc);
  	dlm_lowcomms_commit_buffer(mh);
  }
  
  /* When replying to a status request, a node also sends back its
     configuration values.  The requesting node then checks that the remote
     node is configured the same way as itself. */
  
  static void make_config(struct dlm_ls *ls, struct rcom_config *rf)
  {

  	rf->rf_lvblen = cpu_to_le32(ls->ls_lvblen);
  	rf->rf_lsflags = cpu_to_le32(ls->ls_exflags);

  }

  static int check_config(struct dlm_ls *ls, struct dlm_rcom *rc, int nodeid)

  {

  	struct rcom_config *rf = (struct rcom_config *) rc->rc_buf;

  	size_t conf_size = sizeof(struct dlm_rcom) + sizeof(struct rcom_config);

  
  	if ((rc->rc_header.h_version & 0xFFFF0000) != DLM_HEADER_MAJOR) {
  		log_error(ls, "version mismatch: %x nodeid %d: %x",
  			  DLM_HEADER_MAJOR | DLM_HEADER_MINOR, nodeid,
  			  rc->rc_header.h_version);

  		return -EPROTO;

  	}

  	if (rc->rc_header.h_length < conf_size) {
  		log_error(ls, "config too short: %d nodeid %d",
  			  rc->rc_header.h_length, nodeid);
  		return -EPROTO;
  	}

  	if (le32_to_cpu(rf->rf_lvblen) != ls->ls_lvblen ||
  	    le32_to_cpu(rf->rf_lsflags) != ls->ls_exflags) {

  		log_error(ls, "config mismatch: %d,%x nodeid %d: %d,%x",

  			  ls->ls_lvblen, ls->ls_exflags, nodeid,
  			  le32_to_cpu(rf->rf_lvblen),
  			  le32_to_cpu(rf->rf_lsflags));

  		return -EPROTO;

  	}
  	return 0;
  }

  static void allow_sync_reply(struct dlm_ls *ls, uint64_t *new_seq)
  {
  	spin_lock(&ls->ls_rcom_spin);
  	*new_seq = ++ls->ls_rcom_seq;
  	set_bit(LSFL_RCOM_WAIT, &ls->ls_flags);
  	spin_unlock(&ls->ls_rcom_spin);
  }
  
  static void disallow_sync_reply(struct dlm_ls *ls)
  {
  	spin_lock(&ls->ls_rcom_spin);
  	clear_bit(LSFL_RCOM_WAIT, &ls->ls_flags);
  	clear_bit(LSFL_RCOM_READY, &ls->ls_flags);
  	spin_unlock(&ls->ls_rcom_spin);
  }

  int dlm_rcom_status(struct dlm_ls *ls, int nodeid)
  {
  	struct dlm_rcom *rc;
  	struct dlm_mhandle *mh;
  	int error = 0;

  	ls->ls_recover_nodeid = nodeid;

  
  	if (nodeid == dlm_our_nodeid()) {

  		rc = ls->ls_recover_buf;

  		rc->rc_result = dlm_recover_status(ls);
  		goto out;
  	}
  
  	error = create_rcom(ls, nodeid, DLM_RCOM_STATUS, 0, &rc, &mh);
  	if (error)
  		goto out;

  
  	allow_sync_reply(ls, &rc->rc_id);

  	memset(ls->ls_recover_buf, 0, dlm_config.ci_buffer_size);

  
  	send_rcom(ls, mh, rc);
  
  	error = dlm_wait_function(ls, &rcom_response);

  	disallow_sync_reply(ls);

  	if (error)
  		goto out;

  	rc = ls->ls_recover_buf;

  
  	if (rc->rc_result == -ESRCH) {
  		/* we pretend the remote lockspace exists with 0 status */
  		log_debug(ls, "remote node %d not ready", nodeid);
  		rc->rc_result = 0;
  	} else

  		error = check_config(ls, rc, nodeid);

  	/* the caller looks at rc_result for the remote recovery status */
   out:
  	return error;
  }
  
  static void receive_rcom_status(struct dlm_ls *ls, struct dlm_rcom *rc_in)
  {
  	struct dlm_rcom *rc;
  	struct dlm_mhandle *mh;
  	int error, nodeid = rc_in->rc_header.h_nodeid;
  
  	error = create_rcom(ls, nodeid, DLM_RCOM_STATUS_REPLY,
  			    sizeof(struct rcom_config), &rc, &mh);
  	if (error)
  		return;

  	rc->rc_id = rc_in->rc_id;

  	rc->rc_seq_reply = rc_in->rc_seq;

  	rc->rc_result = dlm_recover_status(ls);
  	make_config(ls, (struct rcom_config *) rc->rc_buf);
  
  	send_rcom(ls, mh, rc);
  }

  static void receive_sync_reply(struct dlm_ls *ls, struct dlm_rcom *rc_in)

  {

  	spin_lock(&ls->ls_rcom_spin);
  	if (!test_bit(LSFL_RCOM_WAIT, &ls->ls_flags) ||
  	    rc_in->rc_id != ls->ls_rcom_seq) {
  		log_debug(ls, "reject reply %d from %d seq %llx expect %llx",
  			  rc_in->rc_type, rc_in->rc_header.h_nodeid,

  			  (unsigned long long)rc_in->rc_id,
  			  (unsigned long long)ls->ls_rcom_seq);

  		goto out;

  	}

  	memcpy(ls->ls_recover_buf, rc_in, rc_in->rc_header.h_length);
  	set_bit(LSFL_RCOM_READY, &ls->ls_flags);

  	clear_bit(LSFL_RCOM_WAIT, &ls->ls_flags);

  	wake_up(&ls->ls_wait_general);

   out:
  	spin_unlock(&ls->ls_rcom_spin);

  }
  
  int dlm_rcom_names(struct dlm_ls *ls, int nodeid, char *last_name, int last_len)
  {
  	struct dlm_rcom *rc;
  	struct dlm_mhandle *mh;

  	int error = 0;
  	int max_size = dlm_config.ci_buffer_size - sizeof(struct dlm_rcom);

  	ls->ls_recover_nodeid = nodeid;

  
  	if (nodeid == dlm_our_nodeid()) {

  		ls->ls_recover_buf->rc_header.h_length =
  			dlm_config.ci_buffer_size;

  		dlm_copy_master_names(ls, last_name, last_len,

  		                      ls->ls_recover_buf->rc_buf,
  		                      max_size, nodeid);

  		goto out;
  	}
  
  	error = create_rcom(ls, nodeid, DLM_RCOM_NAMES, last_len, &rc, &mh);
  	if (error)
  		goto out;
  	memcpy(rc->rc_buf, last_name, last_len);

  
  	allow_sync_reply(ls, &rc->rc_id);

  	memset(ls->ls_recover_buf, 0, dlm_config.ci_buffer_size);

  
  	send_rcom(ls, mh, rc);
  
  	error = dlm_wait_function(ls, &rcom_response);

  	disallow_sync_reply(ls);

   out:
  	return error;
  }
  
  static void receive_rcom_names(struct dlm_ls *ls, struct dlm_rcom *rc_in)
  {
  	struct dlm_rcom *rc;
  	struct dlm_mhandle *mh;

  	int error, inlen, outlen, nodeid;

  
  	nodeid = rc_in->rc_header.h_nodeid;
  	inlen = rc_in->rc_header.h_length - sizeof(struct dlm_rcom);

  	outlen = dlm_config.ci_buffer_size - sizeof(struct dlm_rcom);

  
  	error = create_rcom(ls, nodeid, DLM_RCOM_NAMES_REPLY, outlen, &rc, &mh);
  	if (error)
  		return;

  	rc->rc_id = rc_in->rc_id;

  	rc->rc_seq_reply = rc_in->rc_seq;

  
  	dlm_copy_master_names(ls, rc_in->rc_buf, inlen, rc->rc_buf, outlen,
  			      nodeid);
  	send_rcom(ls, mh, rc);
  }

  int dlm_send_rcom_lookup(struct dlm_rsb *r, int dir_nodeid)
  {
  	struct dlm_rcom *rc;
  	struct dlm_mhandle *mh;
  	struct dlm_ls *ls = r->res_ls;
  	int error;
  
  	error = create_rcom(ls, dir_nodeid, DLM_RCOM_LOOKUP, r->res_length,
  			    &rc, &mh);
  	if (error)
  		goto out;
  	memcpy(rc->rc_buf, r->res_name, r->res_length);
  	rc->rc_id = (unsigned long) r;
  
  	send_rcom(ls, mh, rc);
   out:
  	return error;
  }
  
  static void receive_rcom_lookup(struct dlm_ls *ls, struct dlm_rcom *rc_in)
  {
  	struct dlm_rcom *rc;
  	struct dlm_mhandle *mh;
  	int error, ret_nodeid, nodeid = rc_in->rc_header.h_nodeid;
  	int len = rc_in->rc_header.h_length - sizeof(struct dlm_rcom);
  
  	error = create_rcom(ls, nodeid, DLM_RCOM_LOOKUP_REPLY, 0, &rc, &mh);
  	if (error)
  		return;
  
  	error = dlm_dir_lookup(ls, nodeid, rc_in->rc_buf, len, &ret_nodeid);
  	if (error)
  		ret_nodeid = error;
  	rc->rc_result = ret_nodeid;
  	rc->rc_id = rc_in->rc_id;

  	rc->rc_seq_reply = rc_in->rc_seq;

  
  	send_rcom(ls, mh, rc);
  }
  
  static void receive_rcom_lookup_reply(struct dlm_ls *ls, struct dlm_rcom *rc_in)
  {
  	dlm_recover_master_reply(ls, rc_in);
  }
  
  static void pack_rcom_lock(struct dlm_rsb *r, struct dlm_lkb *lkb,
  			   struct rcom_lock *rl)
  {
  	memset(rl, 0, sizeof(*rl));

  	rl->rl_ownpid = cpu_to_le32(lkb->lkb_ownpid);
  	rl->rl_lkid = cpu_to_le32(lkb->lkb_id);
  	rl->rl_exflags = cpu_to_le32(lkb->lkb_exflags);
  	rl->rl_flags = cpu_to_le32(lkb->lkb_flags);
  	rl->rl_lvbseq = cpu_to_le32(lkb->lkb_lvbseq);

  	rl->rl_rqmode = lkb->lkb_rqmode;
  	rl->rl_grmode = lkb->lkb_grmode;
  	rl->rl_status = lkb->lkb_status;

  	rl->rl_wait_type = cpu_to_le16(lkb->lkb_wait_type);

  	if (lkb->lkb_bastfn)

  		rl->rl_asts |= DLM_CB_BAST;

  	if (lkb->lkb_astfn)

  		rl->rl_asts |= DLM_CB_CAST;

  	rl->rl_namelen = cpu_to_le16(r->res_length);

  	memcpy(rl->rl_name, r->res_name, r->res_length);
  
  	/* FIXME: might we have an lvb without DLM_LKF_VALBLK set ?
  	   If so, receive_rcom_lock_args() won't take this copy. */
  
  	if (lkb->lkb_lvbptr)
  		memcpy(rl->rl_lvb, lkb->lkb_lvbptr, r->res_ls->ls_lvblen);
  }
  
  int dlm_send_rcom_lock(struct dlm_rsb *r, struct dlm_lkb *lkb)
  {
  	struct dlm_ls *ls = r->res_ls;
  	struct dlm_rcom *rc;
  	struct dlm_mhandle *mh;
  	struct rcom_lock *rl;
  	int error, len = sizeof(struct rcom_lock);
  
  	if (lkb->lkb_lvbptr)
  		len += ls->ls_lvblen;
  
  	error = create_rcom(ls, r->res_nodeid, DLM_RCOM_LOCK, len, &rc, &mh);
  	if (error)
  		goto out;
  
  	rl = (struct rcom_lock *) rc->rc_buf;
  	pack_rcom_lock(r, lkb, rl);
  	rc->rc_id = (unsigned long) r;
  
  	send_rcom(ls, mh, rc);
   out:
  	return error;
  }

  /* needs at least dlm_rcom + rcom_lock */

  static void receive_rcom_lock(struct dlm_ls *ls, struct dlm_rcom *rc_in)
  {
  	struct dlm_rcom *rc;
  	struct dlm_mhandle *mh;
  	int error, nodeid = rc_in->rc_header.h_nodeid;
  
  	dlm_recover_master_copy(ls, rc_in);
  
  	error = create_rcom(ls, nodeid, DLM_RCOM_LOCK_REPLY,
  			    sizeof(struct rcom_lock), &rc, &mh);
  	if (error)
  		return;
  
  	/* We send back the same rcom_lock struct we received, but
  	   dlm_recover_master_copy() has filled in rl_remid and rl_result */
  
  	memcpy(rc->rc_buf, rc_in->rc_buf, sizeof(struct rcom_lock));
  	rc->rc_id = rc_in->rc_id;

  	rc->rc_seq_reply = rc_in->rc_seq;

  
  	send_rcom(ls, mh, rc);
  }

  /* If the lockspace doesn't exist then still send a status message
     back; it's possible that it just doesn't have its global_id yet. */
  
  int dlm_send_ls_not_ready(int nodeid, struct dlm_rcom *rc_in)

  {
  	struct dlm_rcom *rc;

  	struct rcom_config *rf;

  	struct dlm_mhandle *mh;
  	char *mb;

  	int mb_len = sizeof(struct dlm_rcom) + sizeof(struct rcom_config);

  	mh = dlm_lowcomms_get_buffer(nodeid, mb_len, GFP_NOFS, &mb);

  	if (!mh)
  		return -ENOBUFS;
  	memset(mb, 0, mb_len);
  
  	rc = (struct dlm_rcom *) mb;
  
  	rc->rc_header.h_version = (DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
  	rc->rc_header.h_lockspace = rc_in->rc_header.h_lockspace;
  	rc->rc_header.h_nodeid = dlm_our_nodeid();
  	rc->rc_header.h_length = mb_len;
  	rc->rc_header.h_cmd = DLM_RCOM;
  
  	rc->rc_type = DLM_RCOM_STATUS_REPLY;

  	rc->rc_id = rc_in->rc_id;

  	rc->rc_seq_reply = rc_in->rc_seq;

  	rc->rc_result = -ESRCH;

  	rf = (struct rcom_config *) rc->rc_buf;

  	rf->rf_lvblen = cpu_to_le32(~0U);

  	dlm_rcom_out(rc);
  	dlm_lowcomms_commit_buffer(mh);
  
  	return 0;
  }

  static int is_old_reply(struct dlm_ls *ls, struct dlm_rcom *rc)
  {
  	uint64_t seq;
  	int rv = 0;
  
  	switch (rc->rc_type) {
  	case DLM_RCOM_STATUS_REPLY:
  	case DLM_RCOM_NAMES_REPLY:
  	case DLM_RCOM_LOOKUP_REPLY:
  	case DLM_RCOM_LOCK_REPLY:
  		spin_lock(&ls->ls_recover_lock);
  		seq = ls->ls_recover_seq;
  		spin_unlock(&ls->ls_recover_lock);
  		if (rc->rc_seq_reply != seq) {

  			log_debug(ls, "ignoring old reply %x from %d "

  				      "seq_reply %llx expect %llx",
  				      rc->rc_type, rc->rc_header.h_nodeid,
  				      (unsigned long long)rc->rc_seq_reply,
  				      (unsigned long long)seq);
  			rv = 1;
  		}
  	}
  	return rv;
  }

  /* Called by dlm_recv; corresponds to dlm_receive_message() but special

     recovery-only comms are sent through here. */

  void dlm_receive_rcom(struct dlm_ls *ls, struct dlm_rcom *rc, int nodeid)

  {

  	int lock_size = sizeof(struct dlm_rcom) + sizeof(struct rcom_lock);

  	if (dlm_recovery_stopped(ls) && (rc->rc_type != DLM_RCOM_STATUS)) {

  		log_debug(ls, "ignoring recovery message %x from %d",

  			  rc->rc_type, nodeid);
  		goto out;
  	}

  	if (is_old_reply(ls, rc))
  		goto out;

  	switch (rc->rc_type) {
  	case DLM_RCOM_STATUS:
  		receive_rcom_status(ls, rc);
  		break;
  
  	case DLM_RCOM_NAMES:
  		receive_rcom_names(ls, rc);
  		break;
  
  	case DLM_RCOM_LOOKUP:
  		receive_rcom_lookup(ls, rc);
  		break;
  
  	case DLM_RCOM_LOCK:

  		if (rc->rc_header.h_length < lock_size)
  			goto Eshort;

  		receive_rcom_lock(ls, rc);
  		break;
  
  	case DLM_RCOM_STATUS_REPLY:

  		receive_sync_reply(ls, rc);

  		break;
  
  	case DLM_RCOM_NAMES_REPLY:

  		receive_sync_reply(ls, rc);

  		break;
  
  	case DLM_RCOM_LOOKUP_REPLY:
  		receive_rcom_lookup_reply(ls, rc);
  		break;
  
  	case DLM_RCOM_LOCK_REPLY:

  		if (rc->rc_header.h_length < lock_size)
  			goto Eshort;

  		dlm_recover_process_copy(ls, rc);

  		break;
  
  	default:

  		log_error(ls, "receive_rcom bad type %d", rc->rc_type);

  	}

  out:

  	return;

  Eshort:
  	log_error(ls, "recovery message %x from %d is too short",
  			  rc->rc_type, nodeid);

  }