/* -*- mode: c; c-basic-offset: 8; -*-
   * vim: noexpandtab sw=8 ts=8 sts=0:
   *
   * sysfile.c
   *
   * Initialize, read, write, etc. system files.
   *
   * 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/fs.h>
  #include <linux/types.h>
  #include <linux/highmem.h>
  
  #include <cluster/masklog.h>
  
  #include "ocfs2.h"
  
  #include "alloc.h"
  #include "dir.h"
  #include "inode.h"
  #include "journal.h"
  #include "sysfile.h"
  
  #include "buffer_head_io.h"
  
  static struct inode * _ocfs2_get_system_file_inode(struct ocfs2_super *osb,
  						   int type,
  						   u32 slot);
  
  #ifdef CONFIG_DEBUG_LOCK_ALLOC
  static struct lock_class_key ocfs2_sysfile_cluster_lock_key[NUM_SYSTEM_INODES];
  #endif
  
  static inline int is_global_system_inode(int type)
  {
  	return type >= OCFS2_FIRST_ONLINE_SYSTEM_INODE &&
  		type <= OCFS2_LAST_GLOBAL_SYSTEM_INODE;
  }
  
  static struct inode **get_local_system_inode(struct ocfs2_super *osb,
  					     int type,
  					     u32 slot)
  {
  	int index;
  	struct inode **local_system_inodes, **free = NULL;
  
  	BUG_ON(slot == OCFS2_INVALID_SLOT);
  	BUG_ON(type < OCFS2_FIRST_LOCAL_SYSTEM_INODE ||
  	       type > OCFS2_LAST_LOCAL_SYSTEM_INODE);
  
  	spin_lock(&osb->osb_lock);
  	local_system_inodes = osb->local_system_inodes;
  	spin_unlock(&osb->osb_lock);
  
  	if (unlikely(!local_system_inodes)) {
  		local_system_inodes = kzalloc(sizeof(struct inode *) *
  					      NUM_LOCAL_SYSTEM_INODES *
  					      osb->max_slots,
  					      GFP_NOFS);
  		if (!local_system_inodes) {
  			mlog_errno(-ENOMEM);
  			/*
  			 * return NULL here so that ocfs2_get_sytem_file_inodes
  			 * will try to create an inode and use it. We will try
  			 * to initialize local_system_inodes next time.
  			 */
  			return NULL;
  		}
  
  		spin_lock(&osb->osb_lock);
  		if (osb->local_system_inodes) {
  			/* Someone has initialized it for us. */
  			free = local_system_inodes;
  			local_system_inodes = osb->local_system_inodes;
  		} else
  			osb->local_system_inodes = local_system_inodes;
  		spin_unlock(&osb->osb_lock);
  		kfree(free);
  	}
  
  	index = (slot * NUM_LOCAL_SYSTEM_INODES) +
  		(type - OCFS2_FIRST_LOCAL_SYSTEM_INODE);
  
  	return &local_system_inodes[index];
  }
  
  struct inode *ocfs2_get_system_file_inode(struct ocfs2_super *osb,
  					  int type,
  					  u32 slot)
  {
  	struct inode *inode = NULL;
  	struct inode **arr = NULL;
  
  	/* avoid the lookup if cached in local system file array */
  	if (is_global_system_inode(type)) {
  		arr = &(osb->global_system_inodes[type]);
  	} else
  		arr = get_local_system_inode(osb, type, slot);
  
  	if (arr && ((inode = *arr) != NULL)) {
  		/* get a ref in addition to the array ref */
  		inode = igrab(inode);
  		BUG_ON(!inode);
  
  		return inode;
  	}
  
  	/* this gets one ref thru iget */
  	inode = _ocfs2_get_system_file_inode(osb, type, slot);
  
  	/* add one more if putting into array for first time */
  	if (arr && inode) {
  		*arr = igrab(inode);
  		BUG_ON(!*arr);
  	}
  	return inode;
  }
  
  static struct inode * _ocfs2_get_system_file_inode(struct ocfs2_super *osb,
  						   int type,
  						   u32 slot)
  {
  	char namebuf[40];
  	struct inode *inode = NULL;
  	u64 blkno;
  	int status = 0;
  
  	ocfs2_sprintf_system_inode_name(namebuf,
  					sizeof(namebuf),
  					type, slot);
  
  	status = ocfs2_lookup_ino_from_name(osb->sys_root_inode, namebuf,
  					    strlen(namebuf), &blkno);
  	if (status < 0) {
  		goto bail;
  	}
  
  	inode = ocfs2_iget(osb, blkno, OCFS2_FI_FLAG_SYSFILE, type);
  	if (IS_ERR(inode)) {
  		mlog_errno(PTR_ERR(inode));
  		inode = NULL;
  		goto bail;
  	}
  #ifdef CONFIG_DEBUG_LOCK_ALLOC
  	if (type == LOCAL_USER_QUOTA_SYSTEM_INODE ||
  	    type == LOCAL_GROUP_QUOTA_SYSTEM_INODE ||
  	    type == JOURNAL_SYSTEM_INODE) {
  		/* Ignore inode lock on these inodes as the lock does not
  		 * really belong to any process and lockdep cannot handle
  		 * that */
  		OCFS2_I(inode)->ip_inode_lockres.l_lockdep_map.key = NULL;
  	} else {
  		lockdep_init_map(&OCFS2_I(inode)->ip_inode_lockres.
  								l_lockdep_map,
  				 ocfs2_system_inodes[type].si_name,
  				 &ocfs2_sysfile_cluster_lock_key[type], 0);
  	}
  #endif
  bail:
  
  	return inode;
  }