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

   * Copyright (C) 2004-2006 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 version 2.

   */

  #include <linux/spinlock.h>
  #include <linux/completion.h>
  #include <linux/buffer_head.h>

  #include <linux/gfs2_ondisk.h>

  #include <linux/namei.h>

  #include <linux/crc32.h>

  
  #include "gfs2.h"

  #include "incore.h"

  #include "dir.h"
  #include "glock.h"

  #include "super.h"

  #include "util.h"

  #include "inode.h"

  
  /**
   * gfs2_drevalidate - Check directory lookup consistency
   * @dentry: the mapping to check

   * @flags: lookup flags

   *
   * Check to make sure the lookup necessary to arrive at this inode from its
   * parent is still good.
   *
   * Returns: 1 if the dentry is ok, 0 if it isn't
   */

  static int gfs2_drevalidate(struct dentry *dentry, unsigned int flags)

  {

  	struct dentry *parent;
  	struct gfs2_sbd *sdp;
  	struct gfs2_inode *dip;
  	struct inode *inode;

  	struct gfs2_holder d_gh;

  	struct gfs2_inode *ip = NULL;

  	int error;

  	int had_lock = 0;

  	if (flags & LOOKUP_RCU)

  		return -ECHILD;
  
  	parent = dget_parent(dentry);
  	sdp = GFS2_SB(parent->d_inode);
  	dip = GFS2_I(parent->d_inode);
  	inode = dentry->d_inode;

  	if (inode) {
  		if (is_bad_inode(inode))
  			goto invalid;
  		ip = GFS2_I(inode);
  	}

  	if (sdp->sd_lockstruct.ls_ops->lm_mount == NULL)

  		goto valid;

  	had_lock = (gfs2_glock_is_locked_by_me(dip->i_gl) != NULL);

  	if (!had_lock) {
  		error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh);
  		if (error)
  			goto fail;
  	} 

  	error = gfs2_dir_check(parent->d_inode, &dentry->d_name, ip);

  	switch (error) {
  	case 0:
  		if (!inode)
  			goto invalid_gunlock;
  		break;
  	case -ENOENT:
  		if (!inode)
  			goto valid_gunlock;
  		goto invalid_gunlock;
  	default:
  		goto fail_gunlock;
  	}

  valid_gunlock:

  	if (!had_lock)
  		gfs2_glock_dq_uninit(&d_gh);

  valid:

  	dput(parent);
  	return 1;

  invalid_gunlock:

  	if (!had_lock)
  		gfs2_glock_dq_uninit(&d_gh);

  invalid:

  	if (check_submounts_and_drop(dentry) != 0)
  		goto valid;

  	dput(parent);
  	return 0;

  fail_gunlock:

  	gfs2_glock_dq_uninit(&d_gh);

  fail:

  	dput(parent);
  	return 0;
  }

  static int gfs2_dhash(const struct dentry *dentry, struct qstr *str)

  {
  	str->hash = gfs2_disk_hash(str->name, str->len);
  	return 0;
  }

  static int gfs2_dentry_delete(const struct dentry *dentry)

  {
  	struct gfs2_inode *ginode;
  
  	if (!dentry->d_inode)
  		return 0;
  
  	ginode = GFS2_I(dentry->d_inode);
  	if (!ginode->i_iopen_gh.gh_gl)
  		return 0;
  
  	if (test_bit(GLF_DEMOTE, &ginode->i_iopen_gh.gh_gl->gl_flags))
  		return 1;
  
  	return 0;
  }

  const struct dentry_operations gfs2_dops = {

  	.d_revalidate = gfs2_drevalidate,

  	.d_hash = gfs2_dhash,

  	.d_delete = gfs2_dentry_delete,

  };