/* -*- mode: c; c-basic-offset: 8; -*-
   * vim: noexpandtab sw=8 ts=8 sts=0:
   *
   * stack_o2cb.c
   *
   * Code which interfaces ocfs2 with the o2cb stack.
   *
   * Copyright (C) 2007 Oracle.  All rights reserved.
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public
   * License as published by the Free Software Foundation, version 2.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * General Public License for more details.
   */

  #include <linux/kernel.h>

  #include <linux/crc32.h>

  #include <linux/slab.h>

  #include <linux/module.h>

  
  /* Needed for AOP_TRUNCATED_PAGE in mlog_errno() */
  #include <linux/fs.h>
  
  #include "cluster/masklog.h"
  #include "cluster/nodemanager.h"
  #include "cluster/heartbeat.h"
  
  #include "stackglue.h"
  
  struct o2dlm_private {
  	struct dlm_eviction_cb op_eviction_cb;
  };

  static struct ocfs2_stack_plugin o2cb_stack;

  /* These should be identical */
  #if (DLM_LOCK_IV != LKM_IVMODE)
  # error Lock modes do not match
  #endif
  #if (DLM_LOCK_NL != LKM_NLMODE)
  # error Lock modes do not match
  #endif
  #if (DLM_LOCK_CR != LKM_CRMODE)
  # error Lock modes do not match
  #endif
  #if (DLM_LOCK_CW != LKM_CWMODE)
  # error Lock modes do not match
  #endif
  #if (DLM_LOCK_PR != LKM_PRMODE)
  # error Lock modes do not match
  #endif
  #if (DLM_LOCK_PW != LKM_PWMODE)
  # error Lock modes do not match
  #endif
  #if (DLM_LOCK_EX != LKM_EXMODE)
  # error Lock modes do not match
  #endif
  static inline int mode_to_o2dlm(int mode)
  {
  	BUG_ON(mode > LKM_MAXMODE);
  
  	return mode;
  }
  
  #define map_flag(_generic, _o2dlm)		\
  	if (flags & (_generic)) {		\
  		flags &= ~(_generic);		\
  		o2dlm_flags |= (_o2dlm);	\
  	}
  static int flags_to_o2dlm(u32 flags)
  {
  	int o2dlm_flags = 0;
  
  	map_flag(DLM_LKF_NOQUEUE, LKM_NOQUEUE);
  	map_flag(DLM_LKF_CANCEL, LKM_CANCEL);
  	map_flag(DLM_LKF_CONVERT, LKM_CONVERT);
  	map_flag(DLM_LKF_VALBLK, LKM_VALBLK);
  	map_flag(DLM_LKF_IVVALBLK, LKM_INVVALBLK);
  	map_flag(DLM_LKF_ORPHAN, LKM_ORPHAN);
  	map_flag(DLM_LKF_FORCEUNLOCK, LKM_FORCE);
  	map_flag(DLM_LKF_TIMEOUT, LKM_TIMEOUT);
  	map_flag(DLM_LKF_LOCAL, LKM_LOCAL);
  
  	/* map_flag() should have cleared every flag passed in */
  	BUG_ON(flags != 0);
  
  	return o2dlm_flags;
  }
  #undef map_flag
  
  /*
   * Map an o2dlm status to standard errno values.
   *
   * o2dlm only uses a handful of these, and returns even fewer to the
   * caller. Still, we try to assign sane values to each error.
   *
   * The following value pairs have special meanings to dlmglue, thus
   * the right hand side needs to stay unique - never duplicate the
   * mapping elsewhere in the table!
   *
   * DLM_NORMAL:		0
   * DLM_NOTQUEUED:	-EAGAIN
   * DLM_CANCELGRANT:	-EBUSY
   * DLM_CANCEL:		-DLM_ECANCEL
   */
  /* Keep in sync with dlmapi.h */
  static int status_map[] = {
  	[DLM_NORMAL]			= 0,		/* Success */
  	[DLM_GRANTED]			= -EINVAL,
  	[DLM_DENIED]			= -EACCES,
  	[DLM_DENIED_NOLOCKS]		= -EACCES,
  	[DLM_WORKING]			= -EACCES,
  	[DLM_BLOCKED]			= -EINVAL,
  	[DLM_BLOCKED_ORPHAN]		= -EINVAL,
  	[DLM_DENIED_GRACE_PERIOD]	= -EACCES,
  	[DLM_SYSERR]			= -ENOMEM,	/* It is what it is */
  	[DLM_NOSUPPORT]			= -EPROTO,
  	[DLM_CANCELGRANT]		= -EBUSY,	/* Cancel after grant */
  	[DLM_IVLOCKID]			= -EINVAL,
  	[DLM_SYNC]			= -EINVAL,
  	[DLM_BADTYPE]			= -EINVAL,
  	[DLM_BADRESOURCE]		= -EINVAL,
  	[DLM_MAXHANDLES]		= -ENOMEM,
  	[DLM_NOCLINFO]			= -EINVAL,
  	[DLM_NOLOCKMGR]			= -EINVAL,
  	[DLM_NOPURGED]			= -EINVAL,
  	[DLM_BADARGS]			= -EINVAL,
  	[DLM_VOID]			= -EINVAL,
  	[DLM_NOTQUEUED]			= -EAGAIN,	/* Trylock failed */
  	[DLM_IVBUFLEN]			= -EINVAL,
  	[DLM_CVTUNGRANT]		= -EPERM,
  	[DLM_BADPARAM]			= -EINVAL,
  	[DLM_VALNOTVALID]		= -EINVAL,
  	[DLM_REJECTED]			= -EPERM,
  	[DLM_ABORT]			= -EINVAL,
  	[DLM_CANCEL]			= -DLM_ECANCEL,	/* Successful cancel */
  	[DLM_IVRESHANDLE]		= -EINVAL,
  	[DLM_DEADLOCK]			= -EDEADLK,
  	[DLM_DENIED_NOASTS]		= -EINVAL,
  	[DLM_FORWARD]			= -EINVAL,
  	[DLM_TIMEOUT]			= -ETIMEDOUT,
  	[DLM_IVGROUPID]			= -EINVAL,
  	[DLM_VERS_CONFLICT]		= -EOPNOTSUPP,
  	[DLM_BAD_DEVICE_PATH]		= -ENOENT,
  	[DLM_NO_DEVICE_PERMISSION]	= -EPERM,
  	[DLM_NO_CONTROL_DEVICE]		= -ENOENT,
  	[DLM_RECOVERING]		= -ENOTCONN,
  	[DLM_MIGRATING]			= -ERESTART,
  	[DLM_MAXSTATS]			= -EINVAL,
  };
  
  static int dlm_status_to_errno(enum dlm_status status)
  {

  	BUG_ON(status < 0 || status >= ARRAY_SIZE(status_map));

  
  	return status_map[status];
  }
  
  static void o2dlm_lock_ast_wrapper(void *astarg)
  {

  	struct ocfs2_dlm_lksb *lksb = astarg;

  	lksb->lksb_conn->cc_proto->lp_lock_ast(lksb);

  }
  
  static void o2dlm_blocking_ast_wrapper(void *astarg, int level)
  {

  	struct ocfs2_dlm_lksb *lksb = astarg;

  	lksb->lksb_conn->cc_proto->lp_blocking_ast(lksb, level);

  }
  
  static void o2dlm_unlock_ast_wrapper(void *astarg, enum dlm_status status)
  {

  	struct ocfs2_dlm_lksb *lksb = astarg;

  	int error = dlm_status_to_errno(status);

  	/*
  	 * In o2dlm, you can get both the lock_ast() for the lock being
  	 * granted and the unlock_ast() for the CANCEL failing.  A
  	 * successful cancel sends DLM_NORMAL here.  If the
  	 * lock grant happened before the cancel arrived, you get
  	 * DLM_CANCELGRANT.
  	 *
  	 * There's no need for the double-ast.  If we see DLM_CANCELGRANT,
  	 * we just ignore it.  We expect the lock_ast() to handle the
  	 * granted lock.
  	 */
  	if (status == DLM_CANCELGRANT)
  		return;

  	lksb->lksb_conn->cc_proto->lp_unlock_ast(lksb, error);

  }
  
  static int o2cb_dlm_lock(struct ocfs2_cluster_connection *conn,
  			 int mode,

  			 struct ocfs2_dlm_lksb *lksb,

  			 u32 flags,
  			 void *name,

  			 unsigned int namelen)

  {
  	enum dlm_status status;
  	int o2dlm_mode = mode_to_o2dlm(mode);
  	int o2dlm_flags = flags_to_o2dlm(flags);
  	int ret;
  
  	status = dlmlock(conn->cc_lockspace, o2dlm_mode, &lksb->lksb_o2dlm,
  			 o2dlm_flags, name, namelen,

  			 o2dlm_lock_ast_wrapper, lksb,

  			 o2dlm_blocking_ast_wrapper);
  	ret = dlm_status_to_errno(status);
  	return ret;
  }
  
  static int o2cb_dlm_unlock(struct ocfs2_cluster_connection *conn,

  			   struct ocfs2_dlm_lksb *lksb,

  			   u32 flags)

  {
  	enum dlm_status status;
  	int o2dlm_flags = flags_to_o2dlm(flags);
  	int ret;
  
  	status = dlmunlock(conn->cc_lockspace, &lksb->lksb_o2dlm,

  			   o2dlm_flags, o2dlm_unlock_ast_wrapper, lksb);

  	ret = dlm_status_to_errno(status);
  	return ret;
  }

  static int o2cb_dlm_lock_status(struct ocfs2_dlm_lksb *lksb)

  {
  	return dlm_status_to_errno(lksb->lksb_o2dlm.status);
  }

  /*
   * o2dlm aways has a "valid" LVB. If the dlm loses track of the LVB
   * contents, it will zero out the LVB.  Thus the caller can always trust
   * the contents.
   */

  static int o2cb_dlm_lvb_valid(struct ocfs2_dlm_lksb *lksb)

  {
  	return 1;
  }

  static void *o2cb_dlm_lvb(struct ocfs2_dlm_lksb *lksb)

  {
  	return (void *)(lksb->lksb_o2dlm.lvb);
  }

  static void o2cb_dump_lksb(struct ocfs2_dlm_lksb *lksb)

  {
  	dlm_print_one_lock(lksb->lksb_o2dlm.lockid);
  }
  
  /*
   * Called from the dlm when it's about to evict a node. This is how the
   * classic stack signals node death.
   */
  static void o2dlm_eviction_cb(int node_num, void *data)
  {
  	struct ocfs2_cluster_connection *conn = data;
  
  	mlog(ML_NOTICE, "o2dlm has evicted node %d from group %.*s
  ",
  	     node_num, conn->cc_namelen, conn->cc_name);
  
  	conn->cc_recovery_handler(node_num, conn->cc_recovery_data);
  }
  
  static int o2cb_cluster_connect(struct ocfs2_cluster_connection *conn)
  {
  	int rc = 0;
  	u32 dlm_key;
  	struct dlm_ctxt *dlm;
  	struct o2dlm_private *priv;

  	struct dlm_protocol_version fs_version;

  
  	BUG_ON(conn == NULL);

  	BUG_ON(conn->cc_proto == NULL);

  
  	/* for now we only have one cluster/node, make sure we see it
  	 * in the heartbeat universe */
  	if (!o2hb_check_local_node_heartbeating()) {

  		if (o2hb_global_heartbeat_active())
  			mlog(ML_ERROR, "Global heartbeat not started
  ");

  		rc = -EINVAL;
  		goto out;
  	}
  
  	priv = kzalloc(sizeof(struct o2dlm_private), GFP_KERNEL);
  	if (!priv) {
  		rc = -ENOMEM;
  		goto out_free;
  	}
  
  	/* This just fills the structure in.  It is safe to pass conn. */
  	dlm_setup_eviction_cb(&priv->op_eviction_cb, o2dlm_eviction_cb,
  			      conn);
  
  	conn->cc_private = priv;
  
  	/* used by the dlm code to make message headers unique, each
  	 * node in this domain must agree on this. */
  	dlm_key = crc32_le(0, conn->cc_name, conn->cc_namelen);

  	fs_version.pv_major = conn->cc_version.pv_major;
  	fs_version.pv_minor = conn->cc_version.pv_minor;

  	dlm = dlm_register_domain(conn->cc_name, dlm_key, &fs_version);

  	if (IS_ERR(dlm)) {
  		rc = PTR_ERR(dlm);
  		mlog_errno(rc);
  		goto out_free;
  	}

  	conn->cc_version.pv_major = fs_version.pv_major;
  	conn->cc_version.pv_minor = fs_version.pv_minor;

  	conn->cc_lockspace = dlm;
  
  	dlm_register_eviction_cb(dlm, &priv->op_eviction_cb);
  
  out_free:
  	if (rc && conn->cc_private)
  		kfree(conn->cc_private);
  
  out:
  	return rc;
  }

  static int o2cb_cluster_disconnect(struct ocfs2_cluster_connection *conn)

  {
  	struct dlm_ctxt *dlm = conn->cc_lockspace;
  	struct o2dlm_private *priv = conn->cc_private;
  
  	dlm_unregister_eviction_cb(&priv->op_eviction_cb);
  	conn->cc_private = NULL;
  	kfree(priv);
  
  	dlm_unregister_domain(dlm);
  	conn->cc_lockspace = NULL;
  
  	return 0;
  }

  static int o2cb_cluster_this_node(unsigned int *node)
  {
  	int node_num;
  
  	node_num = o2nm_this_node();
  	if (node_num == O2NM_INVALID_NODE_NUM)
  		return -ENOENT;
  
  	if (node_num >= O2NM_MAX_NODES)
  		return -EOVERFLOW;
  
  	*node = node_num;
  	return 0;
  }

  static struct ocfs2_stack_operations o2cb_stack_ops = {

  	.connect	= o2cb_cluster_connect,
  	.disconnect	= o2cb_cluster_disconnect,

  	.this_node	= o2cb_cluster_this_node,
  	.dlm_lock	= o2cb_dlm_lock,
  	.dlm_unlock	= o2cb_dlm_unlock,
  	.lock_status	= o2cb_dlm_lock_status,

  	.lvb_valid	= o2cb_dlm_lvb_valid,

  	.lock_lvb	= o2cb_dlm_lvb,
  	.dump_lksb	= o2cb_dump_lksb,
  };

  static struct ocfs2_stack_plugin o2cb_stack = {
  	.sp_name	= "o2cb",
  	.sp_ops		= &o2cb_stack_ops,
  	.sp_owner	= THIS_MODULE,
  };
  
  static int __init o2cb_stack_init(void)
  {
  	return ocfs2_stack_glue_register(&o2cb_stack);
  }
  
  static void __exit o2cb_stack_exit(void)
  {
  	ocfs2_stack_glue_unregister(&o2cb_stack);
  }
  
  MODULE_AUTHOR("Oracle");
  MODULE_DESCRIPTION("ocfs2 driver for the classic o2cb stack");
  MODULE_LICENSE("GPL");
  module_init(o2cb_stack_init);
  module_exit(o2cb_stack_exit);