/*
   *  linux/fs/adfs/dir.c
   *
   *  Copyright (C) 1999-2000 Russell King
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   *
   *  Common directory handling for ADFS
   */
  #include "adfs.h"
  
  /*
   * For future.  This should probably be per-directory.
   */
  static DEFINE_RWLOCK(adfs_dir_lock);
  
  static int
  adfs_readdir(struct file *file, struct dir_context *ctx)
  {
  	struct inode *inode = file_inode(file);
  	struct super_block *sb = inode->i_sb;
  	struct adfs_dir_ops *ops = ADFS_SB(sb)->s_dir;
  	struct object_info obj;
  	struct adfs_dir dir;
  	int ret = 0;
  
  	if (ctx->pos >> 32)
  		return 0;
  
  	ret = ops->read(sb, inode->i_ino, inode->i_size, &dir);
  	if (ret)
  		return ret;
  
  	if (ctx->pos == 0) {
  		if (!dir_emit_dot(file, ctx))
  			goto free_out;
  		ctx->pos = 1;
  	}
  	if (ctx->pos == 1) {
  		if (!dir_emit(ctx, "..", 2, dir.parent_id, DT_DIR))
  			goto free_out;
  		ctx->pos = 2;
  	}
  
  	read_lock(&adfs_dir_lock);
  
  	ret = ops->setpos(&dir, ctx->pos - 2);
  	if (ret)
  		goto unlock_out;
  	while (ops->getnext(&dir, &obj) == 0) {
  		if (!dir_emit(ctx, obj.name, obj.name_len,
  			    obj.file_id, DT_UNKNOWN))
  			break;
  		ctx->pos++;
  	}
  
  unlock_out:
  	read_unlock(&adfs_dir_lock);
  
  free_out:
  	ops->free(&dir);
  	return ret;
  }
  
  int
  adfs_dir_update(struct super_block *sb, struct object_info *obj, int wait)
  {
  	int ret = -EINVAL;
  #ifdef CONFIG_ADFS_FS_RW
  	struct adfs_dir_ops *ops = ADFS_SB(sb)->s_dir;
  	struct adfs_dir dir;
  
  	printk(KERN_INFO "adfs_dir_update: object %06X in dir %06X
  ",
  		 obj->file_id, obj->parent_id);
  
  	if (!ops->update) {
  		ret = -EINVAL;
  		goto out;
  	}
  
  	ret = ops->read(sb, obj->parent_id, 0, &dir);
  	if (ret)
  		goto out;
  
  	write_lock(&adfs_dir_lock);
  	ret = ops->update(&dir, obj);
  	write_unlock(&adfs_dir_lock);
  
  	if (wait) {
  		int err = ops->sync(&dir);
  		if (!ret)
  			ret = err;
  	}
  
  	ops->free(&dir);
  out:
  #endif
  	return ret;
  }
  
  static int
  adfs_match(struct qstr *name, struct object_info *obj)
  {
  	int i;
  
  	if (name->len != obj->name_len)
  		return 0;
  
  	for (i = 0; i < name->len; i++) {
  		char c1, c2;
  
  		c1 = name->name[i];
  		c2 = obj->name[i];
  
  		if (c1 >= 'A' && c1 <= 'Z')
  			c1 += 'a' - 'A';
  		if (c2 >= 'A' && c2 <= 'Z')
  			c2 += 'a' - 'A';
  
  		if (c1 != c2)
  			return 0;
  	}
  	return 1;
  }
  
  static int
  adfs_dir_lookup_byname(struct inode *inode, struct qstr *name, struct object_info *obj)
  {
  	struct super_block *sb = inode->i_sb;
  	struct adfs_dir_ops *ops = ADFS_SB(sb)->s_dir;
  	struct adfs_dir dir;
  	int ret;
  
  	ret = ops->read(sb, inode->i_ino, inode->i_size, &dir);
  	if (ret)
  		goto out;
  
  	if (ADFS_I(inode)->parent_id != dir.parent_id) {
  		adfs_error(sb, "parent directory changed under me! (%lx but got %lx)
  ",
  			   ADFS_I(inode)->parent_id, dir.parent_id);
  		ret = -EIO;
  		goto free_out;
  	}
  
  	obj->parent_id = inode->i_ino;
  
  	/*
  	 * '.' is handled by reserved_lookup() in fs/namei.c
  	 */
  	if (name->len == 2 && name->name[0] == '.' && name->name[1] == '.') {
  		/*
  		 * Currently unable to fill in the rest of 'obj',
  		 * but this is better than nothing.  We need to
  		 * ascend one level to find it's parent.
  		 */
  		obj->name_len = 0;
  		obj->file_id  = obj->parent_id;
  		goto free_out;
  	}
  
  	read_lock(&adfs_dir_lock);
  
  	ret = ops->setpos(&dir, 0);
  	if (ret)
  		goto unlock_out;
  
  	ret = -ENOENT;
  	while (ops->getnext(&dir, obj) == 0) {
  		if (adfs_match(name, obj)) {
  			ret = 0;
  			break;
  		}
  	}
  
  unlock_out:
  	read_unlock(&adfs_dir_lock);
  
  free_out:
  	ops->free(&dir);
  out:
  	return ret;
  }
  
  const struct file_operations adfs_dir_operations = {
  	.read		= generic_read_dir,
  	.llseek		= generic_file_llseek,
  	.iterate	= adfs_readdir,
  	.fsync		= generic_file_fsync,
  };
  
  static int
  adfs_hash(const struct dentry *parent, struct qstr *qstr)
  {
  	const unsigned int name_len = ADFS_SB(parent->d_sb)->s_namelen;
  	const unsigned char *name;
  	unsigned long hash;
  	int i;
  
  	if (qstr->len < name_len)
  		return 0;
  
  	/*
  	 * Truncate the name in place, avoids
  	 * having to define a compare function.
  	 */
  	qstr->len = i = name_len;
  	name = qstr->name;
  	hash = init_name_hash();
  	while (i--) {
  		char c;
  
  		c = *name++;
  		if (c >= 'A' && c <= 'Z')
  			c += 'a' - 'A';
  
  		hash = partial_name_hash(c, hash);
  	}
  	qstr->hash = end_name_hash(hash);
  
  	return 0;
  }
  
  /*
   * Compare two names, taking note of the name length
   * requirements of the underlying filesystem.
   */
  static int
  adfs_compare(const struct dentry *parent, const struct dentry *dentry,
  		unsigned int len, const char *str, const struct qstr *name)
  {
  	int i;
  
  	if (len != name->len)
  		return 1;
  
  	for (i = 0; i < name->len; i++) {
  		char a, b;
  
  		a = str[i];
  		b = name->name[i];
  
  		if (a >= 'A' && a <= 'Z')
  			a += 'a' - 'A';
  		if (b >= 'A' && b <= 'Z')
  			b += 'a' - 'A';
  
  		if (a != b)
  			return 1;
  	}
  	return 0;
  }
  
  const struct dentry_operations adfs_dentry_operations = {
  	.d_hash		= adfs_hash,
  	.d_compare	= adfs_compare,
  };
  
  static struct dentry *
  adfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
  {
  	struct inode *inode = NULL;
  	struct object_info obj;
  	int error;
  
  	error = adfs_dir_lookup_byname(dir, &dentry->d_name, &obj);
  	if (error == 0) {
  		error = -EACCES;
  		/*
  		 * This only returns NULL if get_empty_inode
  		 * fails.
  		 */
  		inode = adfs_iget(dir->i_sb, &obj);
  		if (inode)
  			error = 0;
  	}
  	d_add(dentry, inode);
  	return ERR_PTR(error);
  }
  
  /*
   * directories can handle most operations...
   */
  const struct inode_operations adfs_dir_inode_operations = {
  	.lookup		= adfs_lookup,
  	.setattr	= adfs_notify_change,
  };