fs/adfs/dir_f.c - third_party/linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  *  linux/fs/adfs/dir_f.c
  *
  * Copyright (C) 1997-1999 Russell King
  *
  *  E and F format directory handling
  */
 #include "adfs.h"
 #include "dir_f.h"

 static void adfs_f_free(struct adfs_dir *dir);

 /*
  * Read an (unaligned) value of length 1..4 bytes
  */
 static inline unsigned int adfs_readval(unsigned char *p, int len)
 {
 	unsigned int val = 0;

 	switch (len) {
 	case 4:		val |= p[3] << 24;
 			/* fall through */
 	case 3:		val |= p[2] << 16;
 			/* fall through */
 	case 2:		val |= p[1] << 8;
 			/* fall through */
 	default:	val |= p[0];
 	}
 	return val;
 }

 static inline void adfs_writeval(unsigned char *p, int len, unsigned int val)
 {
 	switch (len) {
 	case 4:		p[3] = val >> 24;
 			/* fall through */
 	case 3:		p[2] = val >> 16;
 			/* fall through */
 	case 2:		p[1] = val >> 8;
 			/* fall through */
 	default:	p[0] = val;
 	}
 }

 #define ror13(v) ((v >> 13) | (v << 19))

 #define dir_u8(idx)				\
 	({ int _buf = idx >> blocksize_bits;	\
 	   int _off = idx - (_buf << blocksize_bits);\
 	  *(u8 *)(bh[_buf]->b_data + _off);	\
 	})

 #define dir_u32(idx)				\
 	({ int _buf = idx >> blocksize_bits;	\
 	   int _off = idx - (_buf << blocksize_bits);\
 	  *(__le32 *)(bh[_buf]->b_data + _off);	\
 	})

 #define bufoff(_bh,_idx)			\
 	({ int _buf = _idx >> blocksize_bits;	\
 	   int _off = _idx - (_buf << blocksize_bits);\
 	  (u8 *)(_bh[_buf]->b_data + _off);	\
 	})

 /*
  * There are some algorithms that are nice in
  * assembler, but a bitch in C...  This is one
  * of them.
  */
 static u8
 adfs_dir_checkbyte(const struct adfs_dir *dir)
 {
 	struct buffer_head * const *bh = dir->bh;
 	const int blocksize_bits = dir->sb->s_blocksize_bits;
 	union { __le32 *ptr32; u8 *ptr8; } ptr, end;
 	u32 dircheck = 0;
 	int last = 5 - 26;
 	int i = 0;

 	/*
 	 * Accumulate each word up to the last whole
 	 * word of the last directory entry.  This
 	 * can spread across several buffer heads.
 	 */
 	do {
 		last += 26;
 		do {
 			dircheck = le32_to_cpu(dir_u32(i)) ^ ror13(dircheck);

 			i += sizeof(u32);
 		} while (i < (last & ~3));
 	} while (dir_u8(last) != 0);

 	/*
 	 * Accumulate the last few bytes.  These
 	 * bytes will be within the same bh.
 	 */
 	if (i != last) {
 		ptr.ptr8 = bufoff(bh, i);
 		end.ptr8 = ptr.ptr8 + last - i;

 		do {
 			dircheck = *ptr.ptr8++ ^ ror13(dircheck);
 		} while (ptr.ptr8 < end.ptr8);
 	}

 	/*
 	 * The directory tail is in the final bh
 	 * Note that contary to the RISC OS PRMs,
 	 * the first few bytes are NOT included
 	 * in the check.  All bytes are in the
 	 * same bh.
 	 */
 	ptr.ptr8 = bufoff(bh, 2008);
 	end.ptr8 = ptr.ptr8 + 36;

 	do {
 		__le32 v = *ptr.ptr32++;
 		dircheck = le32_to_cpu(v) ^ ror13(dircheck);
 	} while (ptr.ptr32 < end.ptr32);

 	return (dircheck ^ (dircheck >> 8) ^ (dircheck >> 16) ^ (dircheck >> 24)) & 0xff;
 }

 /* Read and check that a directory is valid */
 static int adfs_dir_read(struct super_block *sb, u32 indaddr,
 			 unsigned int size, struct adfs_dir *dir)
 {
 	const unsigned int blocksize_bits = sb->s_blocksize_bits;
 	int blk = 0;

 	/*
 	 * Directories which are not a multiple of 2048 bytes
 	 * are considered bad v2 [3.6]
 	 */
 	if (size & 2047)
 		goto bad_dir;

 	size >>= blocksize_bits;

 	dir->nr_buffers = 0;
 	dir->sb = sb;

 	for (blk = 0; blk < size; blk++) {
 		int phys;

 		phys = __adfs_block_map(sb, indaddr, blk);
 		if (!phys) {
 			adfs_error(sb, "dir %06x has a hole at offset %d",
 				   indaddr, blk);
 			goto release_buffers;
 		}

 		dir->bh[blk] = sb_bread(sb, phys);
 		if (!dir->bh[blk])
 			goto release_buffers;
 	}

 	memcpy(&dir->dirhead, bufoff(dir->bh, 0), sizeof(dir->dirhead));
 	memcpy(&dir->dirtail, bufoff(dir->bh, 2007), sizeof(dir->dirtail));

 	if (dir->dirhead.startmasseq != dir->dirtail.new.endmasseq ||
 	    memcmp(&dir->dirhead.startname, &dir->dirtail.new.endname, 4))
 		goto bad_dir;

 	if (memcmp(&dir->dirhead.startname, "Nick", 4) &&
 	    memcmp(&dir->dirhead.startname, "Hugo", 4))
 		goto bad_dir;

 	if (adfs_dir_checkbyte(dir) != dir->dirtail.new.dircheckbyte)
 		goto bad_dir;

 	dir->nr_buffers = blk;

 	return 0;

 bad_dir:
 	adfs_error(sb, "dir %06x is corrupted", indaddr);
 release_buffers:
 	for (blk -= 1; blk >= 0; blk -= 1)
 		brelse(dir->bh[blk]);

 	dir->sb = NULL;

 	return -EIO;
 }

 /*
  * convert a disk-based directory entry to a Linux ADFS directory entry
  */
 static inline void
 adfs_dir2obj(struct adfs_dir *dir, struct object_info *obj,
 	struct adfs_direntry *de)
 {
 	unsigned int name_len;

 	for (name_len = 0; name_len < ADFS_F_NAME_LEN; name_len++) {
 		if (de->dirobname[name_len] < ' ')
 			break;

 		obj->name[name_len] = de->dirobname[name_len];
 	}

 	obj->name_len =	name_len;
 	obj->indaddr  = adfs_readval(de->dirinddiscadd, 3);
 	obj->loadaddr = adfs_readval(de->dirload, 4);
 	obj->execaddr = adfs_readval(de->direxec, 4);
 	obj->size     = adfs_readval(de->dirlen,  4);
 	obj->attr     = de->newdiratts;

 	adfs_object_fixup(dir, obj);
 }

 /*
  * convert a Linux ADFS directory entry to a disk-based directory entry
  */
 static inline void
 adfs_obj2dir(struct adfs_direntry *de, struct object_info *obj)
 {
 	adfs_writeval(de->dirinddiscadd, 3, obj->indaddr);
 	adfs_writeval(de->dirload, 4, obj->loadaddr);
 	adfs_writeval(de->direxec, 4, obj->execaddr);
 	adfs_writeval(de->dirlen,  4, obj->size);
 	de->newdiratts = obj->attr;
 }

 /*
  * get a directory entry.  Note that the caller is responsible
  * for holding the relevant locks.
  */
 static int
 __adfs_dir_get(struct adfs_dir *dir, int pos, struct object_info *obj)
 {
 	struct super_block *sb = dir->sb;
 	struct adfs_direntry de;
 	int thissize, buffer, offset;

 	buffer = pos >> sb->s_blocksize_bits;

 	if (buffer > dir->nr_buffers)
 		return -EINVAL;

 	offset = pos & (sb->s_blocksize - 1);
 	thissize = sb->s_blocksize - offset;
 	if (thissize > 26)
 		thissize = 26;

 	memcpy(&de, dir->bh[buffer]->b_data + offset, thissize);
 	if (thissize != 26)
 		memcpy(((char *)&de) + thissize, dir->bh[buffer + 1]->b_data,
 		       26 - thissize);

 	if (!de.dirobname[0])
 		return -ENOENT;

 	adfs_dir2obj(dir, obj, &de);

 	return 0;
 }

 static int
 __adfs_dir_put(struct adfs_dir *dir, int pos, struct object_info *obj)
 {
 	struct super_block *sb = dir->sb;
 	struct adfs_direntry de;
 	int thissize, buffer, offset;

 	buffer = pos >> sb->s_blocksize_bits;

 	if (buffer > dir->nr_buffers)
 		return -EINVAL;

 	offset = pos & (sb->s_blocksize - 1);
 	thissize = sb->s_blocksize - offset;
 	if (thissize > 26)
 		thissize = 26;

 	/*
 	 * Get the entry in total
 	 */
 	memcpy(&de, dir->bh[buffer]->b_data + offset, thissize);
 	if (thissize != 26)
 		memcpy(((char *)&de) + thissize, dir->bh[buffer + 1]->b_data,
 		       26 - thissize);

 	/*
 	 * update it
 	 */
 	adfs_obj2dir(&de, obj);

 	/*
 	 * Put the new entry back
 	 */
 	memcpy(dir->bh[buffer]->b_data + offset, &de, thissize);
 	if (thissize != 26)
 		memcpy(dir->bh[buffer + 1]->b_data, ((char *)&de) + thissize,
 		       26 - thissize);

 	return 0;
 }

 /*
  * the caller is responsible for holding the necessary
  * locks.
  */
 static int adfs_dir_find_entry(struct adfs_dir *dir, u32 indaddr)
 {
 	int pos, ret;

 	ret = -ENOENT;

 	for (pos = 5; pos < ADFS_NUM_DIR_ENTRIES * 26 + 5; pos += 26) {
 		struct object_info obj;

 		if (!__adfs_dir_get(dir, pos, &obj))
 			break;

 		if (obj.indaddr == indaddr) {
 			ret = pos;
 			break;
 		}
 	}

 	return ret;
 }

 static int adfs_f_read(struct super_block *sb, u32 indaddr, unsigned int size,
 		       struct adfs_dir *dir)
 {
 	int ret;

 	if (size != ADFS_NEWDIR_SIZE)
 		return -EIO;

 	ret = adfs_dir_read(sb, indaddr, size, dir);
 	if (ret)
 		adfs_error(sb, "unable to read directory");
 	else
 		dir->parent_id = adfs_readval(dir->dirtail.new.dirparent, 3);

 	return ret;
 }

 static int
 adfs_f_setpos(struct adfs_dir *dir, unsigned int fpos)
 {
 	if (fpos >= ADFS_NUM_DIR_ENTRIES)
 		return -ENOENT;

 	dir->pos = 5 + fpos * 26;
 	return 0;
 }

 static int
 adfs_f_getnext(struct adfs_dir *dir, struct object_info *obj)
 {
 	unsigned int ret;

 	ret = __adfs_dir_get(dir, dir->pos, obj);
 	if (ret == 0)
 		dir->pos += 26;

 	return ret;
 }

 static int
 adfs_f_update(struct adfs_dir *dir, struct object_info *obj)
 {
 	struct super_block *sb = dir->sb;
 	int ret, i;

 	ret = adfs_dir_find_entry(dir, obj->indaddr);
 	if (ret < 0) {
 		adfs_error(dir->sb, "unable to locate entry to update");
 		goto out;
 	}

 	__adfs_dir_put(dir, ret, obj);

 	/*
 	 * Increment directory sequence number
 	 */
 	dir->bh[0]->b_data[0] += 1;
 	dir->bh[dir->nr_buffers - 1]->b_data[sb->s_blocksize - 6] += 1;

 	ret = adfs_dir_checkbyte(dir);
 	/*
 	 * Update directory check byte
 	 */
 	dir->bh[dir->nr_buffers - 1]->b_data[sb->s_blocksize - 1] = ret;

 #if 1
 	{
 	const unsigned int blocksize_bits = sb->s_blocksize_bits;

 	memcpy(&dir->dirhead, bufoff(dir->bh, 0), sizeof(dir->dirhead));
 	memcpy(&dir->dirtail, bufoff(dir->bh, 2007), sizeof(dir->dirtail));

 	if (dir->dirhead.startmasseq != dir->dirtail.new.endmasseq ||
 	    memcmp(&dir->dirhead.startname, &dir->dirtail.new.endname, 4))
 		goto bad_dir;

 	if (memcmp(&dir->dirhead.startname, "Nick", 4) &&
 	    memcmp(&dir->dirhead.startname, "Hugo", 4))
 		goto bad_dir;

 	if (adfs_dir_checkbyte(dir) != dir->dirtail.new.dircheckbyte)
 		goto bad_dir;
 	}
 #endif
 	for (i = dir->nr_buffers - 1; i >= 0; i--)
 		mark_buffer_dirty(dir->bh[i]);

 	ret = 0;
 out:
 	return ret;
 #if 1
 bad_dir:
 	adfs_error(dir->sb, "whoops!  I broke a directory!");
 	return -EIO;
 #endif
 }

 static int
 adfs_f_sync(struct adfs_dir *dir)
 {
 	int err = 0;
 	int i;

 	for (i = dir->nr_buffers - 1; i >= 0; i--) {
 		struct buffer_head *bh = dir->bh[i];
 		sync_dirty_buffer(bh);
 		if (buffer_req(bh) && !buffer_uptodate(bh))
 			err = -EIO;
 	}

 	return err;
 }

 static void
 adfs_f_free(struct adfs_dir *dir)
 {
 	int i;

 	for (i = dir->nr_buffers - 1; i >= 0; i--) {
 		brelse(dir->bh[i]);
 		dir->bh[i] = NULL;
 	}

 	dir->nr_buffers = 0;
 	dir->sb = NULL;
 }

 const struct adfs_dir_ops adfs_f_dir_ops = {
 	.read		= adfs_f_read,
 	.setpos		= adfs_f_setpos,
 	.getnext	= adfs_f_getnext,
 	.update		= adfs_f_update,
 	.sync		= adfs_f_sync,
 	.free		= adfs_f_free
 };
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* linux/fs/adfs/dir_f.c
	*
	* Copyright (C) 1997-1999 Russell King
	*
	* E and F format directory handling
	*/
	#include "adfs.h"
	#include "dir_f.h"

	static void adfs_f_free(struct adfs_dir *dir);

	/*
	* Read an (unaligned) value of length 1..4 bytes
	*/
	static inline unsigned int adfs_readval(unsigned char *p, int len)
	{
	unsigned int val = 0;

	switch (len) {
	case 4: val \|= p[3] << 24;
	/* fall through */
	case 3: val \|= p[2] << 16;
	/* fall through */
	case 2: val \|= p[1] << 8;
	/* fall through */
	default: val \|= p[0];
	}
	return val;
	}

	static inline void adfs_writeval(unsigned char *p, int len, unsigned int val)
	{
	switch (len) {
	case 4: p[3] = val >> 24;
	/* fall through */
	case 3: p[2] = val >> 16;
	/* fall through */
	case 2: p[1] = val >> 8;
	/* fall through */
	default: p[0] = val;
	}
	}

	#define ror13(v) ((v >> 13) \| (v << 19))

	#define dir_u8(idx) \
	({ int _buf = idx >> blocksize_bits; \
	int _off = idx - (_buf << blocksize_bits);\
	(u8 )(bh[_buf]->b_data + _off); \
	})

	#define dir_u32(idx) \
	({ int _buf = idx >> blocksize_bits; \
	int _off = idx - (_buf << blocksize_bits);\
	(__le32 )(bh[_buf]->b_data + _off); \
	})

	#define bufoff(_bh,_idx) \
	({ int _buf = _idx >> blocksize_bits; \
	int _off = _idx - (_buf << blocksize_bits);\
	(u8 *)(_bh[_buf]->b_data + _off); \
	})

	/*
	* There are some algorithms that are nice in
	* assembler, but a bitch in C... This is one
	* of them.
	*/
	static u8
	adfs_dir_checkbyte(const struct adfs_dir *dir)
	{
	struct buffer_head * const *bh = dir->bh;
	const int blocksize_bits = dir->sb->s_blocksize_bits;
	union { __le32 ptr32; u8 ptr8; } ptr, end;
	u32 dircheck = 0;
	int last = 5 - 26;
	int i = 0;

	/*
	* Accumulate each word up to the last whole
	* word of the last directory entry. This
	* can spread across several buffer heads.
	*/
	do {
	last += 26;
	do {
	dircheck = le32_to_cpu(dir_u32(i)) ^ ror13(dircheck);

	i += sizeof(u32);
	} while (i < (last & ~3));
	} while (dir_u8(last) != 0);

	/*
	* Accumulate the last few bytes. These
	* bytes will be within the same bh.
	*/
	if (i != last) {
	ptr.ptr8 = bufoff(bh, i);
	end.ptr8 = ptr.ptr8 + last - i;

	do {
	dircheck = *ptr.ptr8++ ^ ror13(dircheck);
	} while (ptr.ptr8 < end.ptr8);
	}

	/*
	* The directory tail is in the final bh
	* Note that contary to the RISC OS PRMs,
	* the first few bytes are NOT included
	* in the check. All bytes are in the
	* same bh.
	*/
	ptr.ptr8 = bufoff(bh, 2008);
	end.ptr8 = ptr.ptr8 + 36;

	do {
	__le32 v = *ptr.ptr32++;
	dircheck = le32_to_cpu(v) ^ ror13(dircheck);
	} while (ptr.ptr32 < end.ptr32);

	return (dircheck ^ (dircheck >> 8) ^ (dircheck >> 16) ^ (dircheck >> 24)) & 0xff;
	}

	/* Read and check that a directory is valid */
	static int adfs_dir_read(struct super_block *sb, u32 indaddr,
	unsigned int size, struct adfs_dir *dir)
	{
	const unsigned int blocksize_bits = sb->s_blocksize_bits;
	int blk = 0;

	/*
	* Directories which are not a multiple of 2048 bytes
	* are considered bad v2 [3.6]
	*/
	if (size & 2047)
	goto bad_dir;

	size >>= blocksize_bits;

	dir->nr_buffers = 0;
	dir->sb = sb;

	for (blk = 0; blk < size; blk++) {
	int phys;

	phys = __adfs_block_map(sb, indaddr, blk);
	if (!phys) {
	adfs_error(sb, "dir %06x has a hole at offset %d",
	indaddr, blk);
	goto release_buffers;
	}

	dir->bh[blk] = sb_bread(sb, phys);
	if (!dir->bh[blk])
	goto release_buffers;
	}

	memcpy(&dir->dirhead, bufoff(dir->bh, 0), sizeof(dir->dirhead));
	memcpy(&dir->dirtail, bufoff(dir->bh, 2007), sizeof(dir->dirtail));

	if (dir->dirhead.startmasseq != dir->dirtail.new.endmasseq \|\|
	memcmp(&dir->dirhead.startname, &dir->dirtail.new.endname, 4))
	goto bad_dir;

	if (memcmp(&dir->dirhead.startname, "Nick", 4) &&
	memcmp(&dir->dirhead.startname, "Hugo", 4))
	goto bad_dir;

	if (adfs_dir_checkbyte(dir) != dir->dirtail.new.dircheckbyte)
	goto bad_dir;

	dir->nr_buffers = blk;

	return 0;

	bad_dir:
	adfs_error(sb, "dir %06x is corrupted", indaddr);
	release_buffers:
	for (blk -= 1; blk >= 0; blk -= 1)
	brelse(dir->bh[blk]);

	dir->sb = NULL;

	return -EIO;
	}

	/*
	* convert a disk-based directory entry to a Linux ADFS directory entry
	*/
	static inline void
	adfs_dir2obj(struct adfs_dir dir, struct object_info obj,
	struct adfs_direntry *de)
	{
	unsigned int name_len;

	for (name_len = 0; name_len < ADFS_F_NAME_LEN; name_len++) {
	if (de->dirobname[name_len] < ' ')
	break;

	obj->name[name_len] = de->dirobname[name_len];
	}

	obj->name_len = name_len;
	obj->indaddr = adfs_readval(de->dirinddiscadd, 3);
	obj->loadaddr = adfs_readval(de->dirload, 4);
	obj->execaddr = adfs_readval(de->direxec, 4);
	obj->size = adfs_readval(de->dirlen, 4);
	obj->attr = de->newdiratts;

	adfs_object_fixup(dir, obj);
	}

	/*
	* convert a Linux ADFS directory entry to a disk-based directory entry
	*/
	static inline void
	adfs_obj2dir(struct adfs_direntry de, struct object_info obj)
	{
	adfs_writeval(de->dirinddiscadd, 3, obj->indaddr);
	adfs_writeval(de->dirload, 4, obj->loadaddr);
	adfs_writeval(de->direxec, 4, obj->execaddr);
	adfs_writeval(de->dirlen, 4, obj->size);
	de->newdiratts = obj->attr;
	}

	/*
	* get a directory entry. Note that the caller is responsible
	* for holding the relevant locks.
	*/
	static int
	__adfs_dir_get(struct adfs_dir dir, int pos, struct object_info obj)
	{
	struct super_block *sb = dir->sb;
	struct adfs_direntry de;
	int thissize, buffer, offset;

	buffer = pos >> sb->s_blocksize_bits;

	if (buffer > dir->nr_buffers)
	return -EINVAL;

	offset = pos & (sb->s_blocksize - 1);
	thissize = sb->s_blocksize - offset;
	if (thissize > 26)
	thissize = 26;

	memcpy(&de, dir->bh[buffer]->b_data + offset, thissize);
	if (thissize != 26)
	memcpy(((char *)&de) + thissize, dir->bh[buffer + 1]->b_data,
	26 - thissize);

	if (!de.dirobname[0])
	return -ENOENT;

	adfs_dir2obj(dir, obj, &de);

	return 0;
	}

	static int
	__adfs_dir_put(struct adfs_dir dir, int pos, struct object_info obj)
	{
	struct super_block *sb = dir->sb;
	struct adfs_direntry de;
	int thissize, buffer, offset;

	buffer = pos >> sb->s_blocksize_bits;

	if (buffer > dir->nr_buffers)
	return -EINVAL;

	offset = pos & (sb->s_blocksize - 1);
	thissize = sb->s_blocksize - offset;
	if (thissize > 26)
	thissize = 26;

	/*
	* Get the entry in total
	*/
	memcpy(&de, dir->bh[buffer]->b_data + offset, thissize);
	if (thissize != 26)
	memcpy(((char *)&de) + thissize, dir->bh[buffer + 1]->b_data,
	26 - thissize);

	/*
	* update it
	*/
	adfs_obj2dir(&de, obj);

	/*
	* Put the new entry back
	*/
	memcpy(dir->bh[buffer]->b_data + offset, &de, thissize);
	if (thissize != 26)
	memcpy(dir->bh[buffer + 1]->b_data, ((char *)&de) + thissize,
	26 - thissize);

	return 0;
	}

	/*
	* the caller is responsible for holding the necessary
	* locks.
	*/
	static int adfs_dir_find_entry(struct adfs_dir *dir, u32 indaddr)
	{
	int pos, ret;

	ret = -ENOENT;

	for (pos = 5; pos < ADFS_NUM_DIR_ENTRIES * 26 + 5; pos += 26) {
	struct object_info obj;

	if (!__adfs_dir_get(dir, pos, &obj))
	break;

	if (obj.indaddr == indaddr) {
	ret = pos;
	break;
	}
	}

	return ret;
	}

	static int adfs_f_read(struct super_block *sb, u32 indaddr, unsigned int size,
	struct adfs_dir *dir)
	{
	int ret;

	if (size != ADFS_NEWDIR_SIZE)
	return -EIO;

	ret = adfs_dir_read(sb, indaddr, size, dir);
	if (ret)
	adfs_error(sb, "unable to read directory");
	else
	dir->parent_id = adfs_readval(dir->dirtail.new.dirparent, 3);

	return ret;
	}

	static int
	adfs_f_setpos(struct adfs_dir *dir, unsigned int fpos)
	{
	if (fpos >= ADFS_NUM_DIR_ENTRIES)
	return -ENOENT;

	dir->pos = 5 + fpos * 26;
	return 0;
	}

	static int
	adfs_f_getnext(struct adfs_dir dir, struct object_info obj)
	{
	unsigned int ret;

	ret = __adfs_dir_get(dir, dir->pos, obj);
	if (ret == 0)
	dir->pos += 26;

	return ret;
	}

	static int
	adfs_f_update(struct adfs_dir dir, struct object_info obj)
	{
	struct super_block *sb = dir->sb;
	int ret, i;

	ret = adfs_dir_find_entry(dir, obj->indaddr);
	if (ret < 0) {
	adfs_error(dir->sb, "unable to locate entry to update");
	goto out;
	}

	__adfs_dir_put(dir, ret, obj);

	/*
	* Increment directory sequence number
	*/
	dir->bh[0]->b_data[0] += 1;
	dir->bh[dir->nr_buffers - 1]->b_data[sb->s_blocksize - 6] += 1;

	ret = adfs_dir_checkbyte(dir);
	/*
	* Update directory check byte
	*/
	dir->bh[dir->nr_buffers - 1]->b_data[sb->s_blocksize - 1] = ret;

	#if 1
	{
	const unsigned int blocksize_bits = sb->s_blocksize_bits;

	memcpy(&dir->dirhead, bufoff(dir->bh, 0), sizeof(dir->dirhead));
	memcpy(&dir->dirtail, bufoff(dir->bh, 2007), sizeof(dir->dirtail));

	if (dir->dirhead.startmasseq != dir->dirtail.new.endmasseq \|\|
	memcmp(&dir->dirhead.startname, &dir->dirtail.new.endname, 4))
	goto bad_dir;

	if (memcmp(&dir->dirhead.startname, "Nick", 4) &&
	memcmp(&dir->dirhead.startname, "Hugo", 4))
	goto bad_dir;

	if (adfs_dir_checkbyte(dir) != dir->dirtail.new.dircheckbyte)
	goto bad_dir;
	}
	#endif
	for (i = dir->nr_buffers - 1; i >= 0; i--)
	mark_buffer_dirty(dir->bh[i]);

	ret = 0;
	out:
	return ret;
	#if 1
	bad_dir:
	adfs_error(dir->sb, "whoops! I broke a directory!");
	return -EIO;
	#endif
	}

	static int
	adfs_f_sync(struct adfs_dir *dir)
	{
	int err = 0;
	int i;

	for (i = dir->nr_buffers - 1; i >= 0; i--) {
	struct buffer_head *bh = dir->bh[i];
	sync_dirty_buffer(bh);
	if (buffer_req(bh) && !buffer_uptodate(bh))
	err = -EIO;
	}

	return err;
	}

	static void
	adfs_f_free(struct adfs_dir *dir)
	{
	int i;

	for (i = dir->nr_buffers - 1; i >= 0; i--) {
	brelse(dir->bh[i]);
	dir->bh[i] = NULL;
	}

	dir->nr_buffers = 0;
	dir->sb = NULL;
	}

	const struct adfs_dir_ops adfs_f_dir_ops = {
	.read = adfs_f_read,
	.setpos = adfs_f_setpos,
	.getnext = adfs_f_getnext,
	.update = adfs_f_update,
	.sync = adfs_f_sync,
	.free = adfs_f_free
	};