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generated by cgit v1.2.2 (git 2.25.0) at 2025-11-06 16:15:17 -0500
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/*
 * OMFS (as used by RIO Karma) directory operations.
 * Copyright (C) 2005 Bob Copeland <me@bobcopeland.com>
 * Released under GPL v2.
 */

#include <linux/fs.h>
#include <linux/ctype.h>
#include <linux/buffer_head.h>
#include "omfs.h"

static int omfs_hash(const char *name, int namelen, int mod)
{
	int i, hash = 0;
	for (i = 0; i < namelen; i++)
		hash ^= tolower(name[i]) << (i % 24);
	return hash % mod;
}

/*
 * Finds the bucket for a given name and reads the containing block;
 * *ofs is set to the offset of the first list entry.
 */
static struct buffer_head *omfs_get_bucket(struct inode *dir,
		const char *name, int namelen, int *ofs)
{
	int nbuckets = (dir->i_size - OMFS_DIR_START)/8;
	int bucket = omfs_hash(name, namelen, nbuckets);

	*ofs = OMFS_DIR_START + bucket * 8;
	return omfs_bread(dir->i_sb, dir->i_ino);
}

static struct buffer_head *omfs_scan_list(struct inode *dir, u64 block,
				const char *name, int namelen,
				u64 *prev_block)
{
	struct buffer_head *bh;
	struct omfs_inode *oi;
	int err = -ENOENT;
	*prev_block = ~0;

	while (block != ~0) {
		bh = omfs_bread(dir->i_sb, block);
		if (!bh) {
			err = -EIO;
			goto err;
		}

		oi = (struct omfs_inode *) bh->b_data;
		if (omfs_is_bad(OMFS_SB(dir->i_sb), &oi->i_head, block)) {
			brelse(bh);
			goto err;
		}

		if (strncmp(oi->i_name, name, namelen) == 0)
			return bh;

		*prev_block = block;
		block = be64_to_cpu(oi->i_sibling);
		brelse(bh);
	}
err:
	return ERR_PTR(err);
}

static struct buffer_head *omfs_find_entry(struct inode *dir,
					   const char *name, int namelen)
{
	struct buffer_head *bh;
	int ofs;
	u64 block, dummy;

	bh = omfs_get_bucket(dir, name, namelen, &ofs);
	if (!bh)
		return ERR_PTR(-EIO);

	block = be64_to_cpu(*((__be64 *) &bh->b_data[ofs]));
	brelse(bh);

	return omfs_scan_list(dir, block, name, namelen, &dummy);
}

int omfs_make_empty(struct inode *inode, struct super_block *sb)
{
	struct omfs_sb_info *sbi = OMFS_SB(sb);
	struct buffer_head *bh;
	struct omfs_inode *oi;

	bh = omfs_bread(sb, inode->i_ino);
	if (!bh)
		return -ENOMEM;

	memset(bh->b_data, 0, sizeof(struct omfs_inode));