/* -*- mode: c; c-basic-offset: 8; -*-
   * vim: noexpandtab sw=8 ts=8 sts=0:
   *
   * export.c
   *
   * Functions to facilitate NFS exporting
   *
   * Copyright (C) 2002, 2005 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 <cluster/masklog.h>
  
  #include "ocfs2.h"

  #include "alloc.h"

  #include "dir.h"
  #include "dlmglue.h"

  #include "dcache.h"

  #include "export.h"
  #include "inode.h"
  
  #include "buffer_head_io.h"

  #include "suballoc.h"

  #include "ocfs2_trace.h"

  
  struct ocfs2_inode_handle
  {
  	u64 ih_blkno;
  	u32 ih_generation;
  };

  static struct dentry *ocfs2_get_dentry(struct super_block *sb,
  		struct ocfs2_inode_handle *handle)

  {

  	struct inode *inode;

  	struct ocfs2_super *osb = OCFS2_SB(sb);
  	u64 blkno = handle->ih_blkno;
  	int status, set;

  	struct dentry *result;

  	trace_ocfs2_get_dentry_begin(sb, handle, (unsigned long long)blkno);

  	if (blkno == 0) {

  		result = ERR_PTR(-ESTALE);
  		goto bail;

  	}

  	inode = ocfs2_ilookup(sb, blkno);
  	/*
  	 * If the inode exists in memory, we only need to check it's
  	 * generation number
  	 */
  	if (inode)
  		goto check_gen;

  	/*
  	 * This will synchronize us against ocfs2_delete_inode() on
  	 * all nodes
  	 */
  	status = ocfs2_nfs_sync_lock(osb, 1);
  	if (status < 0) {
  		mlog(ML_ERROR, "getting nfs sync lock(EX) failed %d
  ", status);
  		goto check_err;
  	}
  
  	status = ocfs2_test_inode_bit(osb, blkno, &set);

  	trace_ocfs2_get_dentry_test_bit(status, set);

  	if (status < 0) {
  		if (status == -EINVAL) {
  			/*
  			 * The blkno NFS gave us doesn't even show up
  			 * as an inode, we return -ESTALE to be
  			 * nice
  			 */

  			status = -ESTALE;

  		} else

  			mlog(ML_ERROR, "test inode bit failed %d
  ", status);

  		goto unlock_nfs_sync;
  	}
  
  	/* If the inode allocator bit is clear, this inode must be stale */
  	if (!set) {

  		status = -ESTALE;
  		goto unlock_nfs_sync;
  	}
  
  	inode = ocfs2_iget(osb, blkno, 0, 0);
  
  unlock_nfs_sync:
  	ocfs2_nfs_sync_unlock(osb, 1);
  
  check_err:
  	if (status < 0) {
  		if (status == -ESTALE) {

  			trace_ocfs2_get_dentry_stale((unsigned long long)blkno,
  						     handle->ih_generation);

  		}
  		result = ERR_PTR(status);
  		goto bail;
  	}
  
  	if (IS_ERR(inode)) {
  		mlog_errno(PTR_ERR(inode));
  		result = (void *)inode;
  		goto bail;
  	}

  check_gen:

  	if (handle->ih_generation != inode->i_generation) {
  		iput(inode);

  		trace_ocfs2_get_dentry_generation((unsigned long long)blkno,
  						  handle->ih_generation,
  						  inode->i_generation);

  		result = ERR_PTR(-ESTALE);
  		goto bail;

  	}

  	result = d_obtain_alias(inode);

  	if (IS_ERR(result))

  		mlog_errno(PTR_ERR(result));

  bail:

  	trace_ocfs2_get_dentry_end(result);

  	return result;
  }
  
  static struct dentry *ocfs2_get_parent(struct dentry *child)
  {
  	int status;
  	u64 blkno;
  	struct dentry *parent;

  	struct inode *dir = child->d_inode;

  	trace_ocfs2_get_parent(child, child->d_name.len, child->d_name.name,
  			       (unsigned long long)OCFS2_I(dir)->ip_blkno);

  	status = ocfs2_inode_lock(dir, NULL, 0);

  	if (status < 0) {
  		if (status != -ENOENT)
  			mlog_errno(status);
  		parent = ERR_PTR(status);
  		goto bail;
  	}

  	status = ocfs2_lookup_ino_from_name(dir, "..", 2, &blkno);

  	if (status < 0) {
  		parent = ERR_PTR(-ENOENT);
  		goto bail_unlock;
  	}

  	parent = d_obtain_alias(ocfs2_iget(OCFS2_SB(dir->i_sb), blkno, 0, 0));

  bail_unlock:

  	ocfs2_inode_unlock(dir, 0);

  bail:

  	trace_ocfs2_get_parent_end(parent);

  
  	return parent;
  }

  static int ocfs2_encode_fh(struct dentry *dentry, u32 *fh_in, int *max_len,

  			   int connectable)
  {
  	struct inode *inode = dentry->d_inode;
  	int len = *max_len;
  	int type = 1;
  	u64 blkno;
  	u32 generation;

  	__le32 *fh = (__force __le32 *) fh_in;

  	trace_ocfs2_encode_fh_begin(dentry, dentry->d_name.len,
  				    dentry->d_name.name,
  				    fh, len, connectable);

  	if (connectable && (len < 6)) {
  		*max_len = 6;
  		type = 255;
  		goto bail;
  	} else if (len < 3) {
  		*max_len = 3;

  		type = 255;
  		goto bail;
  	}
  
  	blkno = OCFS2_I(inode)->ip_blkno;
  	generation = inode->i_generation;

  	trace_ocfs2_encode_fh_self((unsigned long long)blkno, generation);

  
  	len = 3;
  	fh[0] = cpu_to_le32((u32)(blkno >> 32));
  	fh[1] = cpu_to_le32((u32)(blkno & 0xffffffff));
  	fh[2] = cpu_to_le32(generation);
  
  	if (connectable && !S_ISDIR(inode->i_mode)) {
  		struct inode *parent;
  
  		spin_lock(&dentry->d_lock);
  
  		parent = dentry->d_parent->d_inode;
  		blkno = OCFS2_I(parent)->ip_blkno;
  		generation = parent->i_generation;
  
  		fh[3] = cpu_to_le32((u32)(blkno >> 32));
  		fh[4] = cpu_to_le32((u32)(blkno & 0xffffffff));
  		fh[5] = cpu_to_le32(generation);
  
  		spin_unlock(&dentry->d_lock);
  
  		len = 6;
  		type = 2;

  		trace_ocfs2_encode_fh_parent((unsigned long long)blkno,
  					     generation);

  	}

  	*max_len = len;
  
  bail:

  	trace_ocfs2_encode_fh_type(type);

  	return type;
  }

  static struct dentry *ocfs2_fh_to_dentry(struct super_block *sb,
  		struct fid *fid, int fh_len, int fh_type)

  {

  	struct ocfs2_inode_handle handle;

  	if (fh_len < 3 || fh_type > 2)
  		return NULL;

  	handle.ih_blkno = (u64)le32_to_cpu(fid->raw[0]) << 32;
  	handle.ih_blkno |= (u64)le32_to_cpu(fid->raw[1]);
  	handle.ih_generation = le32_to_cpu(fid->raw[2]);
  	return ocfs2_get_dentry(sb, &handle);
  }

  static struct dentry *ocfs2_fh_to_parent(struct super_block *sb,
  		struct fid *fid, int fh_len, int fh_type)
  {
  	struct ocfs2_inode_handle parent;

  	if (fh_type != 2 || fh_len < 6)
  		return NULL;

  	parent.ih_blkno = (u64)le32_to_cpu(fid->raw[3]) << 32;
  	parent.ih_blkno |= (u64)le32_to_cpu(fid->raw[4]);
  	parent.ih_generation = le32_to_cpu(fid->raw[5]);
  	return ocfs2_get_dentry(sb, &parent);

  }

  const struct export_operations ocfs2_export_ops = {

  	.encode_fh	= ocfs2_encode_fh,

  	.fh_to_dentry	= ocfs2_fh_to_dentry,
  	.fh_to_parent	= ocfs2_fh_to_parent,

  	.get_parent	= ocfs2_get_parent,

  };