/*
   * Copyright (C) 2005, 2006

   * Avishay Traeger (avishay@gmail.com)

   * Copyright (C) 2008, 2009

   * Boaz Harrosh <ooo@electrozaur.com>

   *
   * Copyrights for code taken from ext2:
   *     Copyright (C) 1992, 1993, 1994, 1995
   *     Remy Card (card@masi.ibp.fr)
   *     Laboratoire MASI - Institut Blaise Pascal
   *     Universite Pierre et Marie Curie (Paris VI)
   *     from
   *     linux/fs/minix/inode.c
   *     Copyright (C) 1991, 1992  Linus Torvalds
   *
   * This file is part of exofs.
   *
   * exofs 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.  Since it is based on ext2, and the only
   * valid version of GPL for the Linux kernel is version 2, the only valid
   * version of GPL for exofs is version 2.
   *
   * exofs 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 exofs; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
   */
  
  #include "exofs.h"
  
  static inline int exofs_add_nondir(struct dentry *dentry, struct inode *inode)
  {
  	int err = exofs_add_link(dentry, inode);
  	if (!err) {
  		d_instantiate(dentry, inode);
  		return 0;
  	}
  	inode_dec_link_count(inode);
  	iput(inode);
  	return err;
  }
  
  static struct dentry *exofs_lookup(struct inode *dir, struct dentry *dentry,

  				   unsigned int flags)

  {
  	struct inode *inode;
  	ino_t ino;
  
  	if (dentry->d_name.len > EXOFS_NAME_LEN)
  		return ERR_PTR(-ENAMETOOLONG);
  
  	ino = exofs_inode_by_name(dir, dentry);

  	inode = ino ? exofs_iget(dir->i_sb, ino) : NULL;

  	return d_splice_alias(inode, dentry);
  }

  static int exofs_create(struct inode *dir, struct dentry *dentry, umode_t mode,

  			 bool excl)

  {
  	struct inode *inode = exofs_new_inode(dir, mode);
  	int err = PTR_ERR(inode);
  	if (!IS_ERR(inode)) {
  		inode->i_op = &exofs_file_inode_operations;
  		inode->i_fop = &exofs_file_operations;
  		inode->i_mapping->a_ops = &exofs_aops;
  		mark_inode_dirty(inode);
  		err = exofs_add_nondir(dentry, inode);
  	}
  	return err;
  }

  static int exofs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,

  		       dev_t rdev)
  {
  	struct inode *inode;
  	int err;

  	inode = exofs_new_inode(dir, mode);
  	err = PTR_ERR(inode);
  	if (!IS_ERR(inode)) {
  		init_special_inode(inode, inode->i_mode, rdev);
  		mark_inode_dirty(inode);
  		err = exofs_add_nondir(dentry, inode);
  	}
  	return err;
  }
  
  static int exofs_symlink(struct inode *dir, struct dentry *dentry,
  			  const char *symname)
  {
  	struct super_block *sb = dir->i_sb;
  	int err = -ENAMETOOLONG;
  	unsigned l = strlen(symname)+1;
  	struct inode *inode;
  	struct exofs_i_info *oi;
  
  	if (l > sb->s_blocksize)
  		goto out;
  
  	inode = exofs_new_inode(dir, S_IFLNK | S_IRWXUGO);
  	err = PTR_ERR(inode);
  	if (IS_ERR(inode))
  		goto out;
  
  	oi = exofs_i(inode);
  	if (l > sizeof(oi->i_data)) {
  		/* slow symlink */

  		inode->i_op = &page_symlink_inode_operations;

  		inode_nohighmem(inode);

  		inode->i_mapping->a_ops = &exofs_aops;
  		memset(oi->i_data, 0, sizeof(oi->i_data));
  
  		err = page_symlink(inode, symname, l);
  		if (err)
  			goto out_fail;
  	} else {
  		/* fast symlink */

  		inode->i_op = &simple_symlink_inode_operations;
  		inode->i_link = (char *)oi->i_data;

  		memcpy(oi->i_data, symname, l);
  		inode->i_size = l-1;
  	}
  	mark_inode_dirty(inode);
  
  	err = exofs_add_nondir(dentry, inode);
  out:
  	return err;
  
  out_fail:
  	inode_dec_link_count(inode);
  	iput(inode);
  	goto out;
  }
  
  static int exofs_link(struct dentry *old_dentry, struct inode *dir,
  		struct dentry *dentry)
  {

  	struct inode *inode = d_inode(old_dentry);

  	inode->i_ctime = current_time(inode);

  	inode_inc_link_count(inode);

  	ihold(inode);

  
  	return exofs_add_nondir(dentry, inode);
  }

  static int exofs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)

  {
  	struct inode *inode;

  	int err;

  
  	inode_inc_link_count(dir);
  
  	inode = exofs_new_inode(dir, S_IFDIR | mode);
  	err = PTR_ERR(inode);
  	if (IS_ERR(inode))
  		goto out_dir;
  
  	inode->i_op = &exofs_dir_inode_operations;
  	inode->i_fop = &exofs_dir_operations;
  	inode->i_mapping->a_ops = &exofs_aops;
  
  	inode_inc_link_count(inode);
  
  	err = exofs_make_empty(inode, dir);
  	if (err)
  		goto out_fail;
  
  	err = exofs_add_link(dentry, inode);
  	if (err)
  		goto out_fail;
  
  	d_instantiate(dentry, inode);
  out:
  	return err;
  
  out_fail:
  	inode_dec_link_count(inode);
  	inode_dec_link_count(inode);
  	iput(inode);
  out_dir:
  	inode_dec_link_count(dir);
  	goto out;
  }
  
  static int exofs_unlink(struct inode *dir, struct dentry *dentry)
  {

  	struct inode *inode = d_inode(dentry);

  	struct exofs_dir_entry *de;
  	struct page *page;
  	int err = -ENOENT;
  
  	de = exofs_find_entry(dir, dentry, &page);
  	if (!de)
  		goto out;
  
  	err = exofs_delete_entry(de, page);
  	if (err)
  		goto out;
  
  	inode->i_ctime = dir->i_ctime;
  	inode_dec_link_count(inode);
  	err = 0;
  out:
  	return err;
  }
  
  static int exofs_rmdir(struct inode *dir, struct dentry *dentry)
  {

  	struct inode *inode = d_inode(dentry);

  	int err = -ENOTEMPTY;
  
  	if (exofs_empty_dir(inode)) {
  		err = exofs_unlink(dir, dentry);
  		if (!err) {
  			inode->i_size = 0;
  			inode_dec_link_count(inode);
  			inode_dec_link_count(dir);
  		}
  	}
  	return err;
  }
  
  static int exofs_rename(struct inode *old_dir, struct dentry *old_dentry,

  			struct inode *new_dir, struct dentry *new_dentry,
  			unsigned int flags)

  {

  	struct inode *old_inode = d_inode(old_dentry);
  	struct inode *new_inode = d_inode(new_dentry);

  	struct page *dir_page = NULL;
  	struct exofs_dir_entry *dir_de = NULL;
  	struct page *old_page;
  	struct exofs_dir_entry *old_de;
  	int err = -ENOENT;

  	if (flags & ~RENAME_NOREPLACE)
  		return -EINVAL;

  	old_de = exofs_find_entry(old_dir, old_dentry, &old_page);
  	if (!old_de)
  		goto out;
  
  	if (S_ISDIR(old_inode->i_mode)) {
  		err = -EIO;
  		dir_de = exofs_dotdot(old_inode, &dir_page);
  		if (!dir_de)
  			goto out_old;
  	}
  
  	if (new_inode) {
  		struct page *new_page;
  		struct exofs_dir_entry *new_de;
  
  		err = -ENOTEMPTY;
  		if (dir_de && !exofs_empty_dir(new_inode))
  			goto out_dir;
  
  		err = -ENOENT;
  		new_de = exofs_find_entry(new_dir, new_dentry, &new_page);
  		if (!new_de)
  			goto out_dir;

  		err = exofs_set_link(new_dir, new_de, new_page, old_inode);

  		new_inode->i_ctime = current_time(new_inode);

  		if (dir_de)
  			drop_nlink(new_inode);
  		inode_dec_link_count(new_inode);
  		if (err)
  			goto out_dir;
  	} else {

  		err = exofs_add_link(new_dentry, old_inode);

  		if (err)

  			goto out_dir;

  		if (dir_de)
  			inode_inc_link_count(new_dir);
  	}

  	old_inode->i_ctime = current_time(old_inode);

  
  	exofs_delete_entry(old_de, old_page);

  	mark_inode_dirty(old_inode);

  
  	if (dir_de) {
  		err = exofs_set_link(old_inode, dir_de, dir_page, new_dir);
  		inode_dec_link_count(old_dir);
  		if (err)
  			goto out_dir;
  	}
  	return 0;
  
  
  out_dir:
  	if (dir_de) {
  		kunmap(dir_page);

  		put_page(dir_page);

  	}
  out_old:
  	kunmap(old_page);

  	put_page(old_page);

  out:
  	return err;
  }
  
  const struct inode_operations exofs_dir_inode_operations = {
  	.create 	= exofs_create,
  	.lookup 	= exofs_lookup,
  	.link   	= exofs_link,
  	.unlink 	= exofs_unlink,
  	.symlink	= exofs_symlink,
  	.mkdir  	= exofs_mkdir,
  	.rmdir  	= exofs_rmdir,
  	.mknod  	= exofs_mknod,

  	.rename		= exofs_rename,

  	.setattr	= exofs_setattr,
  };
  
  const struct inode_operations exofs_special_inode_operations = {
  	.setattr	= exofs_setattr,
  };