/* -*- mode: c; c-basic-offset: 8; -*-
   * vim: noexpandtab sw=8 ts=8 sts=0:
   *
   * slot_map.c
   *
   *
   *
   * Copyright (C) 2002, 2004 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; either
   * version 2 of the License, or (at your option) any later version.
   *
   * 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.
   *
   * You should have received a copy of the GNU General Public
   * License along with this program; if not, write to the
   * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   * Boston, MA 021110-1307, USA.
   */
  
  #include <linux/types.h>
  #include <linux/slab.h>
  #include <linux/highmem.h>

  #include <cluster/masklog.h>
  
  #include "ocfs2.h"
  
  #include "dlmglue.h"
  #include "extent_map.h"
  #include "heartbeat.h"
  #include "inode.h"
  #include "slot_map.h"
  #include "super.h"
  #include "sysfile.h"

  #include "ocfs2_trace.h"

  
  #include "buffer_head_io.h"

  
  struct ocfs2_slot {
  	int sl_valid;
  	unsigned int sl_node_num;
  };

  struct ocfs2_slot_info {

  	int si_extended;
  	int si_slots_per_block;

  	struct inode *si_inode;

  	unsigned int si_blocks;
  	struct buffer_head **si_bh;

  	unsigned int si_num_slots;

  	struct ocfs2_slot *si_slots;

  };

  static int __ocfs2_node_num_to_slot(struct ocfs2_slot_info *si,
  				    unsigned int node_num);
  
  static void ocfs2_invalidate_slot(struct ocfs2_slot_info *si,
  				  int slot_num)
  {
  	BUG_ON((slot_num < 0) || (slot_num >= si->si_num_slots));
  	si->si_slots[slot_num].sl_valid = 0;
  }
  
  static void ocfs2_set_slot(struct ocfs2_slot_info *si,
  			   int slot_num, unsigned int node_num)
  {
  	BUG_ON((slot_num < 0) || (slot_num >= si->si_num_slots));

  
  	si->si_slots[slot_num].sl_valid = 1;
  	si->si_slots[slot_num].sl_node_num = node_num;
  }

  /* This version is for the extended slot map */
  static void ocfs2_update_slot_info_extended(struct ocfs2_slot_info *si)
  {
  	int b, i, slotno;
  	struct ocfs2_slot_map_extended *se;
  
  	slotno = 0;
  	for (b = 0; b < si->si_blocks; b++) {
  		se = (struct ocfs2_slot_map_extended *)si->si_bh[b]->b_data;
  		for (i = 0;
  		     (i < si->si_slots_per_block) &&
  		     (slotno < si->si_num_slots);
  		     i++, slotno++) {
  			if (se->se_slots[i].es_valid)
  				ocfs2_set_slot(si, slotno,
  					       le32_to_cpu(se->se_slots[i].es_node_num));
  			else
  				ocfs2_invalidate_slot(si, slotno);
  		}
  	}
  }

  /*
   * Post the slot information on disk into our slot_info struct.
   * Must be protected by osb_lock.
   */

  static void ocfs2_update_slot_info_old(struct ocfs2_slot_info *si)

  {
  	int i;

  	struct ocfs2_slot_map *sm;

  	sm = (struct ocfs2_slot_map *)si->si_bh[0]->b_data;

  	for (i = 0; i < si->si_num_slots; i++) {

  		if (le16_to_cpu(sm->sm_slots[i]) == (u16)OCFS2_INVALID_SLOT)

  			ocfs2_invalidate_slot(si, i);
  		else

  			ocfs2_set_slot(si, i, le16_to_cpu(sm->sm_slots[i]));

  	}

  }

  static void ocfs2_update_slot_info(struct ocfs2_slot_info *si)
  {
  	/*
  	 * The slot data will have been refreshed when ocfs2_super_lock
  	 * was taken.
  	 */
  	if (si->si_extended)
  		ocfs2_update_slot_info_extended(si);
  	else
  		ocfs2_update_slot_info_old(si);
  }

  int ocfs2_refresh_slot_info(struct ocfs2_super *osb)
  {
  	int ret;
  	struct ocfs2_slot_info *si = osb->slot_info;

  
  	if (si == NULL)
  		return 0;

  	BUG_ON(si->si_blocks == 0);
  	BUG_ON(si->si_bh == NULL);

  	trace_ocfs2_refresh_slot_info(si->si_blocks);

  
  	/*
  	 * We pass -1 as blocknr because we expect all of si->si_bh to
  	 * be !NULL.  Thus, ocfs2_read_blocks() will ignore blocknr.  If
  	 * this is not true, the read of -1 (UINT64_MAX) will fail.
  	 */

  	ret = ocfs2_read_blocks(INODE_CACHE(si->si_inode), -1, si->si_blocks,
  				si->si_bh, OCFS2_BH_IGNORE_CACHE, NULL);

  	if (ret == 0) {
  		spin_lock(&osb->osb_lock);

  		ocfs2_update_slot_info(si);

  		spin_unlock(&osb->osb_lock);
  	}

  
  	return ret;
  }

  /* post the our slot info stuff into it's destination bh and write it
   * out. */

  static void ocfs2_update_disk_slot_extended(struct ocfs2_slot_info *si,
  					    int slot_num,
  					    struct buffer_head **bh)
  {
  	int blkind = slot_num / si->si_slots_per_block;
  	int slotno = slot_num % si->si_slots_per_block;
  	struct ocfs2_slot_map_extended *se;
  
  	BUG_ON(blkind >= si->si_blocks);
  
  	se = (struct ocfs2_slot_map_extended *)si->si_bh[blkind]->b_data;
  	se->se_slots[slotno].es_valid = si->si_slots[slot_num].sl_valid;
  	if (si->si_slots[slot_num].sl_valid)
  		se->se_slots[slotno].es_node_num =
  			cpu_to_le32(si->si_slots[slot_num].sl_node_num);
  	*bh = si->si_bh[blkind];
  }
  
  static void ocfs2_update_disk_slot_old(struct ocfs2_slot_info *si,
  				       int slot_num,
  				       struct buffer_head **bh)

  {

  	int i;

  	struct ocfs2_slot_map *sm;

  	sm = (struct ocfs2_slot_map *)si->si_bh[0]->b_data;

  	for (i = 0; i < si->si_num_slots; i++) {
  		if (si->si_slots[i].sl_valid)

  			sm->sm_slots[i] =

  				cpu_to_le16(si->si_slots[i].sl_node_num);
  		else

  			sm->sm_slots[i] = cpu_to_le16(OCFS2_INVALID_SLOT);

  	}

  	*bh = si->si_bh[0];
  }
  
  static int ocfs2_update_disk_slot(struct ocfs2_super *osb,
  				  struct ocfs2_slot_info *si,
  				  int slot_num)
  {
  	int status;
  	struct buffer_head *bh;
  
  	spin_lock(&osb->osb_lock);
  	if (si->si_extended)
  		ocfs2_update_disk_slot_extended(si, slot_num, &bh);
  	else
  		ocfs2_update_disk_slot_old(si, slot_num, &bh);

  	spin_unlock(&osb->osb_lock);

  	status = ocfs2_write_block(osb, bh, INODE_CACHE(si->si_inode));

  	if (status < 0)
  		mlog_errno(status);
  
  	return status;
  }

  /*
   * Calculate how many bytes are needed by the slot map.  Returns
   * an error if the slot map file is too small.
   */
  static int ocfs2_slot_map_physical_size(struct ocfs2_super *osb,
  					struct inode *inode,
  					unsigned long long *bytes)
  {
  	unsigned long long bytes_needed;

  	if (ocfs2_uses_extended_slot_map(osb)) {
  		bytes_needed = osb->max_slots *
  			sizeof(struct ocfs2_extended_slot);
  	} else {
  		bytes_needed = osb->max_slots * sizeof(__le16);
  	}

  	if (bytes_needed > i_size_read(inode)) {
  		mlog(ML_ERROR,
  		     "Slot map file is too small!  (size %llu, needed %llu)
  ",
  		     i_size_read(inode), bytes_needed);
  		return -ENOSPC;
  	}
  
  	*bytes = bytes_needed;
  	return 0;
  }

  /* try to find global node in the slot info. Returns -ENOENT
   * if nothing is found. */
  static int __ocfs2_node_num_to_slot(struct ocfs2_slot_info *si,
  				    unsigned int node_num)

  {

  	int i, ret = -ENOENT;

  
  	for(i = 0; i < si->si_num_slots; i++) {

  		if (si->si_slots[i].sl_valid &&
  		    (node_num == si->si_slots[i].sl_node_num)) {
  			ret = i;

  			break;
  		}
  	}

  	return ret;
  }

  static int __ocfs2_find_empty_slot(struct ocfs2_slot_info *si,
  				   int preferred)

  {

  	int i, ret = -ENOSPC;

  	if ((preferred >= 0) && (preferred < si->si_num_slots)) {
  		if (!si->si_slots[preferred].sl_valid) {

  			ret = preferred;
  			goto out;
  		}
  	}

  	for(i = 0; i < si->si_num_slots; i++) {

  		if (!si->si_slots[i].sl_valid) {
  			ret = i;

  			break;
  		}
  	}

  out:

  	return ret;
  }

  int ocfs2_node_num_to_slot(struct ocfs2_super *osb, unsigned int node_num)

  {

  	int slot;

  	struct ocfs2_slot_info *si = osb->slot_info;

  	spin_lock(&osb->osb_lock);
  	slot = __ocfs2_node_num_to_slot(si, node_num);
  	spin_unlock(&osb->osb_lock);

  	return slot;
  }
  
  int ocfs2_slot_to_node_num_locked(struct ocfs2_super *osb, int slot_num,
  				  unsigned int *node_num)
  {
  	struct ocfs2_slot_info *si = osb->slot_info;
  
  	assert_spin_locked(&osb->osb_lock);
  
  	BUG_ON(slot_num < 0);
  	BUG_ON(slot_num > osb->max_slots);

  	if (!si->si_slots[slot_num].sl_valid)

  		return -ENOENT;

  	*node_num = si->si_slots[slot_num].sl_node_num;

  	return 0;

  }

  static void __ocfs2_free_slot_info(struct ocfs2_slot_info *si)
  {

  	unsigned int i;

  	if (si == NULL)
  		return;
  
  	if (si->si_inode)
  		iput(si->si_inode);

  	if (si->si_bh) {
  		for (i = 0; i < si->si_blocks; i++) {
  			if (si->si_bh[i]) {
  				brelse(si->si_bh[i]);
  				si->si_bh[i] = NULL;
  			}
  		}
  		kfree(si->si_bh);
  	}

  
  	kfree(si);
  }

  int ocfs2_clear_slot(struct ocfs2_super *osb, int slot_num)

  {

  	struct ocfs2_slot_info *si = osb->slot_info;
  
  	if (si == NULL)
  		return 0;

  	spin_lock(&osb->osb_lock);

  	ocfs2_invalidate_slot(si, slot_num);

  	spin_unlock(&osb->osb_lock);

  	return ocfs2_update_disk_slot(osb, osb->slot_info, slot_num);

  }

  static int ocfs2_map_slot_buffers(struct ocfs2_super *osb,
  				  struct ocfs2_slot_info *si)
  {
  	int status = 0;
  	u64 blkno;

  	unsigned long long blocks, bytes = 0;

  	unsigned int i;
  	struct buffer_head *bh;
  
  	status = ocfs2_slot_map_physical_size(osb, si->si_inode, &bytes);
  	if (status)
  		goto bail;
  
  	blocks = ocfs2_blocks_for_bytes(si->si_inode->i_sb, bytes);
  	BUG_ON(blocks > UINT_MAX);
  	si->si_blocks = blocks;
  	if (!si->si_blocks)
  		goto bail;

  	if (si->si_extended)
  		si->si_slots_per_block =
  			(osb->sb->s_blocksize /
  			 sizeof(struct ocfs2_extended_slot));
  	else
  		si->si_slots_per_block = osb->sb->s_blocksize / sizeof(__le16);
  
  	/* The size checks above should ensure this */
  	BUG_ON((osb->max_slots / si->si_slots_per_block) > blocks);

  	trace_ocfs2_map_slot_buffers(bytes, si->si_blocks);

  
  	si->si_bh = kzalloc(sizeof(struct buffer_head *) * si->si_blocks,
  			    GFP_KERNEL);
  	if (!si->si_bh) {
  		status = -ENOMEM;
  		mlog_errno(status);
  		goto bail;
  	}
  
  	for (i = 0; i < si->si_blocks; i++) {
  		status = ocfs2_extent_map_get_blocks(si->si_inode, i,
  						     &blkno, NULL, NULL);
  		if (status < 0) {
  			mlog_errno(status);
  			goto bail;
  		}

  		trace_ocfs2_map_slot_buffers_block((unsigned long long)blkno, i);

  
  		bh = NULL;  /* Acquire a fresh bh */

  		status = ocfs2_read_blocks(INODE_CACHE(si->si_inode), blkno,
  					   1, &bh, OCFS2_BH_IGNORE_CACHE, NULL);

  		if (status < 0) {
  			mlog_errno(status);
  			goto bail;
  		}
  
  		si->si_bh[i] = bh;
  	}
  
  bail:
  	return status;
  }

  int ocfs2_init_slot_info(struct ocfs2_super *osb)
  {

  	int status;

  	struct inode *inode = NULL;

  	struct ocfs2_slot_info *si;

  	si = kzalloc(sizeof(struct ocfs2_slot_info) +
  		     (sizeof(struct ocfs2_slot) * osb->max_slots),
  		     GFP_KERNEL);

  	if (!si) {
  		status = -ENOMEM;
  		mlog_errno(status);
  		goto bail;
  	}

  	si->si_extended = ocfs2_uses_extended_slot_map(osb);

  	si->si_num_slots = osb->max_slots;

  	si->si_slots = (struct ocfs2_slot *)((char *)si +
  					     sizeof(struct ocfs2_slot_info));

  
  	inode = ocfs2_get_system_file_inode(osb, SLOT_MAP_SYSTEM_INODE,
  					    OCFS2_INVALID_SLOT);
  	if (!inode) {
  		status = -EINVAL;
  		mlog_errno(status);
  		goto bail;
  	}

  	si->si_inode = inode;
  	status = ocfs2_map_slot_buffers(osb, si);

  	if (status < 0) {
  		mlog_errno(status);
  		goto bail;
  	}

  	osb->slot_info = (struct ocfs2_slot_info *)si;

  bail:
  	if (status < 0 && si)

  		__ocfs2_free_slot_info(si);

  
  	return status;
  }

  void ocfs2_free_slot_info(struct ocfs2_super *osb)

  {

  	struct ocfs2_slot_info *si = osb->slot_info;
  
  	osb->slot_info = NULL;
  	__ocfs2_free_slot_info(si);

  }
  
  int ocfs2_find_slot(struct ocfs2_super *osb)
  {
  	int status;

  	int slot;

  	struct ocfs2_slot_info *si;

  	si = osb->slot_info;

  	spin_lock(&osb->osb_lock);

  	ocfs2_update_slot_info(si);

  	/* search for ourselves first and take the slot if it already
  	 * exists. Perhaps we need to mark this in a variable for our
  	 * own journal recovery? Possibly not, though we certainly
  	 * need to warn to the user */
  	slot = __ocfs2_node_num_to_slot(si, osb->node_num);

  	if (slot < 0) {

  		/* if no slot yet, then just take 1st available
  		 * one. */

  		slot = __ocfs2_find_empty_slot(si, osb->preferred_slot);

  		if (slot < 0) {

  			spin_unlock(&osb->osb_lock);

  			mlog(ML_ERROR, "no free slots available!
  ");
  			status = -EINVAL;
  			goto bail;
  		}
  	} else

  		printk(KERN_INFO "ocfs2: Slot %d on device (%s) was already "
  		       "allocated to this node!
  ", slot, osb->dev_str);

  	ocfs2_set_slot(si, slot, osb->node_num);

  	osb->slot_num = slot;

  	spin_unlock(&osb->osb_lock);

  	trace_ocfs2_find_slot(osb->slot_num);

  	status = ocfs2_update_disk_slot(osb, si, osb->slot_num);

  	if (status < 0)
  		mlog_errno(status);
  
  bail:

  	return status;
  }
  
  void ocfs2_put_slot(struct ocfs2_super *osb)
  {

  	int status, slot_num;

  	struct ocfs2_slot_info *si = osb->slot_info;
  
  	if (!si)
  		return;

  	spin_lock(&osb->osb_lock);

  	ocfs2_update_slot_info(si);

  	slot_num = osb->slot_num;

  	ocfs2_invalidate_slot(si, osb->slot_num);

  	osb->slot_num = OCFS2_INVALID_SLOT;

  	spin_unlock(&osb->osb_lock);

  	status = ocfs2_update_disk_slot(osb, si, slot_num);

  	if (status < 0) {
  		mlog_errno(status);
  		goto bail;
  	}
  
  bail:

  	ocfs2_free_slot_info(osb);

  }