// SPDX-License-Identifier: GPL-2.0

  /*
   *  linux/fs/minix/namei.c
   *
   *  Copyright (C) 1991, 1992  Linus Torvalds
   */
  
  #include "minix.h"

  static int add_nondir(struct dentry *dentry, struct inode *inode)
  {
  	int err = minix_add_link(dentry, inode);
  	if (!err) {
  		d_instantiate(dentry, inode);
  		return 0;
  	}

  	inode_dec_link_count(inode);

  	iput(inode);
  	return err;
  }

  static struct dentry *minix_lookup(struct inode * dir, struct dentry *dentry, unsigned int flags)

  {
  	struct inode * inode = NULL;
  	ino_t ino;

  	if (dentry->d_name.len > minix_sb(dir->i_sb)->s_namelen)
  		return ERR_PTR(-ENAMETOOLONG);
  
  	ino = minix_inode_by_name(dentry);

  	if (ino)

  		inode = minix_iget(dir->i_sb, ino);

  	return d_splice_alias(inode, dentry);

  }

  static int minix_mknod(struct inode * dir, struct dentry *dentry, umode_t mode, dev_t rdev)

  {
  	int error;
  	struct inode *inode;
  
  	if (!old_valid_dev(rdev))
  		return -EINVAL;

  	inode = minix_new_inode(dir, mode, &error);

  
  	if (inode) {

  		minix_set_inode(inode, rdev);
  		mark_inode_dirty(inode);
  		error = add_nondir(dentry, inode);
  	}
  	return error;
  }

  static int minix_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
  {
  	int error;
  	struct inode *inode = minix_new_inode(dir, mode, &error);
  	if (inode) {
  		minix_set_inode(inode, 0);
  		mark_inode_dirty(inode);
  		d_tmpfile(dentry, inode);
  	}
  	return error;
  }

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

  		bool excl)

  {
  	return minix_mknod(dir, dentry, mode, 0);
  }
  
  static int minix_symlink(struct inode * dir, struct dentry *dentry,
  	  const char * symname)
  {
  	int err = -ENAMETOOLONG;
  	int i = strlen(symname)+1;
  	struct inode * inode;
  
  	if (i > dir->i_sb->s_blocksize)
  		goto out;

  	inode = minix_new_inode(dir, S_IFLNK | 0777, &err);

  	if (!inode)
  		goto out;

  	minix_set_inode(inode, 0);
  	err = page_symlink(inode, symname, i);
  	if (err)
  		goto out_fail;
  
  	err = add_nondir(dentry, inode);
  out:
  	return err;
  
  out_fail:

  	inode_dec_link_count(inode);

  	iput(inode);
  	goto out;
  }
  
  static int minix_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 add_nondir(dentry, inode);
  }

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

  {
  	struct inode * inode;

  	int err;

  	inode_inc_link_count(dir);

  	inode = minix_new_inode(dir, S_IFDIR | mode, &err);

  	if (!inode)
  		goto out_dir;

  	minix_set_inode(inode, 0);

  	inode_inc_link_count(inode);

  
  	err = minix_make_empty(inode, dir);
  	if (err)
  		goto out_fail;
  
  	err = minix_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 minix_unlink(struct inode * dir, struct dentry *dentry)
  {
  	int err = -ENOENT;

  	struct inode * inode = d_inode(dentry);

  	struct page * page;
  	struct minix_dir_entry * de;
  
  	de = minix_find_entry(dentry, &page);
  	if (!de)
  		goto end_unlink;
  
  	err = minix_delete_entry(de, page);
  	if (err)
  		goto end_unlink;
  
  	inode->i_ctime = dir->i_ctime;

  	inode_dec_link_count(inode);

  end_unlink:
  	return err;
  }
  
  static int minix_rmdir(struct inode * dir, struct dentry *dentry)
  {

  	struct inode * inode = d_inode(dentry);

  	int err = -ENOTEMPTY;
  
  	if (minix_empty_dir(inode)) {
  		err = minix_unlink(dir, dentry);
  		if (!err) {

  			inode_dec_link_count(dir);
  			inode_dec_link_count(inode);

  		}
  	}
  	return err;
  }
  
  static int minix_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 minix_dir_entry * dir_de = NULL;
  	struct page * old_page;
  	struct minix_dir_entry * old_de;
  	int err = -ENOENT;

  	if (flags & ~RENAME_NOREPLACE)
  		return -EINVAL;

  	old_de = minix_find_entry(old_dentry, &old_page);
  	if (!old_de)
  		goto out;
  
  	if (S_ISDIR(old_inode->i_mode)) {
  		err = -EIO;
  		dir_de = minix_dotdot(old_inode, &dir_page);
  		if (!dir_de)
  			goto out_old;
  	}
  
  	if (new_inode) {
  		struct page * new_page;
  		struct minix_dir_entry * new_de;
  
  		err = -ENOTEMPTY;
  		if (dir_de && !minix_empty_dir(new_inode))
  			goto out_dir;
  
  		err = -ENOENT;
  		new_de = minix_find_entry(new_dentry, &new_page);
  		if (!new_de)
  			goto out_dir;

  		minix_set_link(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);

  	} else {

  		err = minix_add_link(new_dentry, old_inode);

  		if (err)

  			goto out_dir;

  		if (dir_de)

  			inode_inc_link_count(new_dir);

  	}
  
  	minix_delete_entry(old_de, old_page);

  	mark_inode_dirty(old_inode);

  
  	if (dir_de) {
  		minix_set_link(dir_de, dir_page, new_dir);

  		inode_dec_link_count(old_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;
  }
  
  /*
   * directories can handle most operations...
   */

  const struct inode_operations minix_dir_inode_operations = {

  	.create		= minix_create,
  	.lookup		= minix_lookup,
  	.link		= minix_link,
  	.unlink		= minix_unlink,
  	.symlink	= minix_symlink,
  	.mkdir		= minix_mkdir,
  	.rmdir		= minix_rmdir,
  	.mknod		= minix_mknod,
  	.rename		= minix_rename,
  	.getattr	= minix_getattr,

  	.tmpfile	= minix_tmpfile,

  };