[people/ms/linux.git] / fs / adfs / dir_f.c

/*
 *  linux/fs/adfs/dir_f.c
 *
 * Copyright (C) 1997-1999 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.
 *
 *  E and F format directory handling
 */
#include <linux/buffer_head.h>
#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;
	case 3:		val |= p[2] << 16;
	case 2:		val |= p[1] << 8;
	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;
	case 3:		p[2] = val >> 16;
	case 2:		p[1] = val >> 8;
	default:	p[0] = val;
	}
}

static inline int adfs_readname(char *buf, char *ptr, int maxlen)
{
	char *old_buf = buf;

	while ((unsigned char)*ptr >= ' ' && maxlen--) {
		if (*ptr == '/')
			*buf++ = '.';
		else
			*buf++ = *ptr;
		ptr++;
	}

	return buf - old_buf;
}

#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, unsigned long object_id,
	      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, object_id, blk);
		if (!phys) {
			adfs_error(sb, "dir object %lX has a hole at offset %d",
				   object_id, 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, "corrupted directory fragment %lX",
		   object_id);
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)
{
	obj->name_len =	adfs_readname(obj->name, de->dirobname, ADFS_F_NAME_LEN);
	obj->file_id  = 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;
	obj->filetype = -1;

	/*
	 * object is a file and is filetyped and timestamped?
	 * RISC OS 12-bit filetype is stored in load_address[19:8]
	 */
	if ((0 == (obj->attr & ADFS_NDA_DIRECTORY)) &&
		(0xfff00000 == (0xfff00000 & obj->loadaddr))) {
		obj->filetype = (__u16) ((0x000fff00 & obj->loadaddr) >> 8);

		/* optionally append the ,xyz hex filetype suffix */
		if (ADFS_SB(dir->sb)->s_ftsuffix)
			obj->name_len +=
				append_filetype_suffix(
					&obj->name[obj->name_len],
					obj->filetype);
	}
}

/*
 * 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->file_id);
	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, unsigned long object_id)
{
	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.file_id == object_id) {
			ret = pos;
			break;
		}
	}

	return ret;
}

static int
adfs_f_read(struct super_block *sb, unsigned int id, unsigned int sz, struct adfs_dir *dir)
{
	int ret;

	if (sz != ADFS_NEWDIR_SIZE)
		return -EIO;

	ret = adfs_dir_read(sb, id, sz, 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->file_id);
	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;
}

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
};
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/adfs/dir_f.c
	3	*
	4	* Copyright (C) 1997-1999 Russell King
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*
	10	* E and F format directory handling
	11	*/
1da177e4	12	#include <linux/buffer_head.h>
1da177e4 LT	13	#include "adfs.h"
	14	#include "dir_f.h"
	15
	16	static void adfs_f_free(struct adfs_dir *dir);
	17
	18	/*
	19	* Read an (unaligned) value of length 1..4 bytes
	20	*/
	21	static inline unsigned int adfs_readval(unsigned char *p, int len)
	22	{
	23	unsigned int val = 0;
	24
	25	switch (len) {
	26	case 4: val \|= p[3] << 24;
	27	case 3: val \|= p[2] << 16;
	28	case 2: val \|= p[1] << 8;
	29	default: val \|= p[0];
	30	}
	31	return val;
	32	}
	33
	34	static inline void adfs_writeval(unsigned char *p, int len, unsigned int val)
	35	{
	36	switch (len) {
	37	case 4: p[3] = val >> 24;
	38	case 3: p[2] = val >> 16;
	39	case 2: p[1] = val >> 8;
	40	default: p[0] = val;
	41	}
	42	}
	43
	44	static inline int adfs_readname(char buf, char ptr, int maxlen)
	45	{
	46	char *old_buf = buf;
	47
3223ea8c	48	while ((unsigned char)*ptr >= ' ' && maxlen--) {
1da177e4 LT	49	if (*ptr == '/')
	50	*buf++ = '.';
	51	else
	52	buf++ = ptr;
	53	ptr++;
	54	}
1da177e4 LT	55
	56	return buf - old_buf;
	57	}
	58
	59	#define ror13(v) ((v >> 13) \| (v << 19))
	60
	61	#define dir_u8(idx) \
	62	({ int _buf = idx >> blocksize_bits; \
	63	int _off = idx - (_buf << blocksize_bits);\
	64	(u8 )(bh[_buf]->b_data + _off); \
	65	})
	66
	67	#define dir_u32(idx) \
	68	({ int _buf = idx >> blocksize_bits; \
	69	int _off = idx - (_buf << blocksize_bits);\
	70	(__le32 )(bh[_buf]->b_data + _off); \
	71	})
	72
	73	#define bufoff(_bh,_idx) \
	74	({ int _buf = _idx >> blocksize_bits; \
	75	int _off = _idx - (_buf << blocksize_bits);\
	76	(u8 *)(_bh[_buf]->b_data + _off); \
	77	})
	78
	79	/*
	80	* There are some algorithms that are nice in
	81	* assembler, but a bitch in C... This is one
	82	* of them.
	83	*/
	84	static u8
	85	adfs_dir_checkbyte(const struct adfs_dir *dir)
	86	{
	87	struct buffer_head * const *bh = dir->bh;
	88	const int blocksize_bits = dir->sb->s_blocksize_bits;
	89	union { __le32 ptr32; u8 ptr8; } ptr, end;
	90	u32 dircheck = 0;
	91	int last = 5 - 26;
	92	int i = 0;
	93
	94	/*
	95	* Accumulate each word up to the last whole
	96	* word of the last directory entry. This
	97	* can spread across several buffer heads.
	98	*/
	99	do {
	100	last += 26;
	101	do {
	102	dircheck = le32_to_cpu(dir_u32(i)) ^ ror13(dircheck);
	103
	104	i += sizeof(u32);
	105	} while (i < (last & ~3));
	106	} while (dir_u8(last) != 0);
	107
	108	/*
	109	* Accumulate the last few bytes. These
	110	* bytes will be within the same bh.
	111	*/
	112	if (i != last) {
	113	ptr.ptr8 = bufoff(bh, i);
	114	end.ptr8 = ptr.ptr8 + last - i;
	115
e5949050	116	do {
1da177e4	117	dircheck = *ptr.ptr8++ ^ ror13(dircheck);
e5949050	118	} while (ptr.ptr8 < end.ptr8);
1da177e4 LT	119	}
	120
	121	/*
	122	* The directory tail is in the final bh
	123	* Note that contary to the RISC OS PRMs,
	124	* the first few bytes are NOT included
	125	* in the check. All bytes are in the
	126	* same bh.
	127	*/
	128	ptr.ptr8 = bufoff(bh, 2008);
	129	end.ptr8 = ptr.ptr8 + 36;
	130
	131	do {
	132	__le32 v = *ptr.ptr32++;
	133	dircheck = le32_to_cpu(v) ^ ror13(dircheck);
	134	} while (ptr.ptr32 < end.ptr32);
	135
	136	return (dircheck ^ (dircheck >> 8) ^ (dircheck >> 16) ^ (dircheck >> 24)) & 0xff;
	137	}
	138
	139	/*
	140	* Read and check that a directory is valid
	141	*/
	142	static int
	143	adfs_dir_read(struct super_block *sb, unsigned long object_id,
	144	unsigned int size, struct adfs_dir *dir)
	145	{
	146	const unsigned int blocksize_bits = sb->s_blocksize_bits;
	147	int blk = 0;
	148
	149	/*
	150	* Directories which are not a multiple of 2048 bytes
	151	* are considered bad v2 [3.6]
	152	*/
	153	if (size & 2047)
	154	goto bad_dir;
	155
	156	size >>= blocksize_bits;
	157
	158	dir->nr_buffers = 0;
	159	dir->sb = sb;
	160
	161	for (blk = 0; blk < size; blk++) {
	162	int phys;
	163
	164	phys = __adfs_block_map(sb, object_id, blk);
	165	if (!phys) {
	166	adfs_error(sb, "dir object %lX has a hole at offset %d",
	167	object_id, blk);
	168	goto release_buffers;
	169	}
	170
	171	dir->bh[blk] = sb_bread(sb, phys);
	172	if (!dir->bh[blk])
	173	goto release_buffers;
	174	}
	175
	176	memcpy(&dir->dirhead, bufoff(dir->bh, 0), sizeof(dir->dirhead));
	177	memcpy(&dir->dirtail, bufoff(dir->bh, 2007), sizeof(dir->dirtail));
	178
	179	if (dir->dirhead.startmasseq != dir->dirtail.new.endmasseq \|\|
	180	memcmp(&dir->dirhead.startname, &dir->dirtail.new.endname, 4))
	181	goto bad_dir;
	182
183	if (memcmp(&dir->dirhead.startname, "Nick", 4) &&
184	memcmp(&dir->dirhead.startname, "Hugo", 4))
185	goto bad_dir;
186
187	if (adfs_dir_checkbyte(dir) != dir->dirtail.new.dircheckbyte)
188	goto bad_dir;
189
190	dir->nr_buffers = blk;
191
192	return 0;
193
194	bad_dir:
195	adfs_error(sb, "corrupted directory fragment %lX",
196	object_id);
197	release_buffers:
198	for (blk -= 1; blk >= 0; blk -= 1)
199	brelse(dir->bh[blk]);
200
201	dir->sb = NULL;
202
203	return -EIO;
204	}
205
206	/*
207	* convert a disk-based directory entry to a Linux ADFS directory entry
208	*/
209	static inline void
da23ef05 SS	210	adfs_dir2obj(struct adfs_dir dir, struct object_info obj,
da23ef05 SS	211	struct adfs_direntry *de)
1da177e4 LT	212	{
	213	obj->name_len = adfs_readname(obj->name, de->dirobname, ADFS_F_NAME_LEN);
	214	obj->file_id = adfs_readval(de->dirinddiscadd, 3);
	215	obj->loadaddr = adfs_readval(de->dirload, 4);
	216	obj->execaddr = adfs_readval(de->direxec, 4);
	217	obj->size = adfs_readval(de->dirlen, 4);
	218	obj->attr = de->newdiratts;
da23ef05 SS	219	obj->filetype = -1;
	220
	221	/*
	222	* object is a file and is filetyped and timestamped?
	223	* RISC OS 12-bit filetype is stored in load_address[19:8]
	224	*/
	225	if ((0 == (obj->attr & ADFS_NDA_DIRECTORY)) &&
	226	(0xfff00000 == (0xfff00000 & obj->loadaddr))) {
	227	obj->filetype = (__u16) ((0x000fff00 & obj->loadaddr) >> 8);
	228
	229	/* optionally append the ,xyz hex filetype suffix */
	230	if (ADFS_SB(dir->sb)->s_ftsuffix)
	231	obj->name_len +=
	232	append_filetype_suffix(
	233	&obj->name[obj->name_len],
	234	obj->filetype);
	235	}
1da177e4 LT	236	}
	237
	238	/*
	239	* convert a Linux ADFS directory entry to a disk-based directory entry
	240	*/
	241	static inline void
	242	adfs_obj2dir(struct adfs_direntry de, struct object_info obj)
	243	{
	244	adfs_writeval(de->dirinddiscadd, 3, obj->file_id);
	245	adfs_writeval(de->dirload, 4, obj->loadaddr);
	246	adfs_writeval(de->direxec, 4, obj->execaddr);
	247	adfs_writeval(de->dirlen, 4, obj->size);
	248	de->newdiratts = obj->attr;
	249	}
	250
	251	/*
	252	* get a directory entry. Note that the caller is responsible
	253	* for holding the relevant locks.
	254	*/
	255	static int
	256	__adfs_dir_get(struct adfs_dir dir, int pos, struct object_info obj)
	257	{
	258	struct super_block *sb = dir->sb;
	259	struct adfs_direntry de;
	260	int thissize, buffer, offset;
	261
	262	buffer = pos >> sb->s_blocksize_bits;
	263
	264	if (buffer > dir->nr_buffers)
	265	return -EINVAL;
	266
	267	offset = pos & (sb->s_blocksize - 1);
	268	thissize = sb->s_blocksize - offset;
	269	if (thissize > 26)
	270	thissize = 26;
	271
	272	memcpy(&de, dir->bh[buffer]->b_data + offset, thissize);
	273	if (thissize != 26)
	274	memcpy(((char *)&de) + thissize, dir->bh[buffer + 1]->b_data,
	275	26 - thissize);
	276
	277	if (!de.dirobname[0])
	278	return -ENOENT;
	279
da23ef05	280	adfs_dir2obj(dir, obj, &de);
1da177e4 LT	281
	282	return 0;
	283	}
	284
	285	static int
	286	__adfs_dir_put(struct adfs_dir dir, int pos, struct object_info obj)
	287	{
	288	struct super_block *sb = dir->sb;
	289	struct adfs_direntry de;
	290	int thissize, buffer, offset;
	291
	292	buffer = pos >> sb->s_blocksize_bits;
	293
	294	if (buffer > dir->nr_buffers)
	295	return -EINVAL;
	296
	297	offset = pos & (sb->s_blocksize - 1);
	298	thissize = sb->s_blocksize - offset;
	299	if (thissize > 26)
	300	thissize = 26;
	301
	302	/*
	303	* Get the entry in total
	304	*/
	305	memcpy(&de, dir->bh[buffer]->b_data + offset, thissize);
	306	if (thissize != 26)
	307	memcpy(((char *)&de) + thissize, dir->bh[buffer + 1]->b_data,
	308	26 - thissize);
	309
	310	/*
	311	* update it
	312	*/
	313	adfs_obj2dir(&de, obj);
	314
	315	/*
	316	* Put the new entry back
	317	*/
	318	memcpy(dir->bh[buffer]->b_data + offset, &de, thissize);
	319	if (thissize != 26)
	320	memcpy(dir->bh[buffer + 1]->b_data, ((char *)&de) + thissize,
	321	26 - thissize);
	322
	323	return 0;
	324	}
	325
	326	/*
	327	* the caller is responsible for holding the necessary
	328	* locks.
	329	*/
	330	static int
	331	adfs_dir_find_entry(struct adfs_dir *dir, unsigned long object_id)
	332	{
	333	int pos, ret;
	334
	335	ret = -ENOENT;
	336
	337	for (pos = 5; pos < ADFS_NUM_DIR_ENTRIES * 26 + 5; pos += 26) {
	338	struct object_info obj;
	339
	340	if (!__adfs_dir_get(dir, pos, &obj))
	341	break;
	342
	343	if (obj.file_id == object_id) {
	344	ret = pos;
345	break;
346	}
347	}
348
349	return ret;
350	}
351
352	static int
353	adfs_f_read(struct super_block sb, unsigned int id, unsigned int sz, struct adfs_dir dir)
354	{
355	int ret;
356
357	if (sz != ADFS_NEWDIR_SIZE)
358	return -EIO;
359
360	ret = adfs_dir_read(sb, id, sz, dir);
361	if (ret)
362	adfs_error(sb, "unable to read directory");
363	else
364	dir->parent_id = adfs_readval(dir->dirtail.new.dirparent, 3);
365
366	return ret;
367	}
368
369	static int
370	adfs_f_setpos(struct adfs_dir *dir, unsigned int fpos)
371	{
372	if (fpos >= ADFS_NUM_DIR_ENTRIES)
373	return -ENOENT;
374
375	dir->pos = 5 + fpos * 26;
376	return 0;
377	}
378
379	static int
380	adfs_f_getnext(struct adfs_dir dir, struct object_info obj)
381	{
382	unsigned int ret;
383
384	ret = __adfs_dir_get(dir, dir->pos, obj);
385	if (ret == 0)
386	dir->pos += 26;
387
388	return ret;
389	}
390
391	static int
392	adfs_f_update(struct adfs_dir dir, struct object_info obj)
393	{
394	struct super_block *sb = dir->sb;
395	int ret, i;
396
397	ret = adfs_dir_find_entry(dir, obj->file_id);
398	if (ret < 0) {
399	adfs_error(dir->sb, "unable to locate entry to update");
400	goto out;
401	}
402
403	__adfs_dir_put(dir, ret, obj);
404
405	/*
406	* Increment directory sequence number
407	*/
408	dir->bh[0]->b_data[0] += 1;
409	dir->bh[dir->nr_buffers - 1]->b_data[sb->s_blocksize - 6] += 1;
410
411	ret = adfs_dir_checkbyte(dir);
412	/*
413	* Update directory check byte
414	*/
415	dir->bh[dir->nr_buffers - 1]->b_data[sb->s_blocksize - 1] = ret;
416
417	#if 1
418	{
419	const unsigned int blocksize_bits = sb->s_blocksize_bits;
420
421	memcpy(&dir->dirhead, bufoff(dir->bh, 0), sizeof(dir->dirhead));
422	memcpy(&dir->dirtail, bufoff(dir->bh, 2007), sizeof(dir->dirtail));
423
424	if (dir->dirhead.startmasseq != dir->dirtail.new.endmasseq \|\|
425	memcmp(&dir->dirhead.startname, &dir->dirtail.new.endname, 4))
426	goto bad_dir;
427
428	if (memcmp(&dir->dirhead.startname, "Nick", 4) &&
429	memcmp(&dir->dirhead.startname, "Hugo", 4))
430	goto bad_dir;
431
432	if (adfs_dir_checkbyte(dir) != dir->dirtail.new.dircheckbyte)
433	goto bad_dir;
434	}
435	#endif
436	for (i = dir->nr_buffers - 1; i >= 0; i--)
437	mark_buffer_dirty(dir->bh[i]);
438
439	ret = 0;
440	out:
441	return ret;
442	#if 1
443	bad_dir:
444	adfs_error(dir->sb, "whoops! I broke a directory!");
445	return -EIO;
446	#endif
447	}
448
ffdc9064 AV	449	static int
	450	adfs_f_sync(struct adfs_dir *dir)
	451	{
	452	int err = 0;
	453	int i;
	454
	455	for (i = dir->nr_buffers - 1; i >= 0; i--) {
	456	struct buffer_head *bh = dir->bh[i];
	457	sync_dirty_buffer(bh);
	458	if (buffer_req(bh) && !buffer_uptodate(bh))
	459	err = -EIO;
	460	}
	461
	462	return err;
	463	}
	464
1da177e4 LT	465	static void
	466	adfs_f_free(struct adfs_dir *dir)
	467	{
	468	int i;
	469
	470	for (i = dir->nr_buffers - 1; i >= 0; i--) {
	471	brelse(dir->bh[i]);
	472	dir->bh[i] = NULL;
	473	}
	474
	475	dir->nr_buffers = 0;
	476	dir->sb = NULL;
	477	}
	478
	479	struct adfs_dir_ops adfs_f_dir_ops = {
	480	.read = adfs_f_read,
	481	.setpos = adfs_f_setpos,
	482	.getnext = adfs_f_getnext,
	483	.update = adfs_f_update,
ffdc9064	484	.sync = adfs_f_sync,
1da177e4 LT	485	.free = adfs_f_free
1da177e4 LT	486	};