[linux.git] / fs / bfs / dir.c

/*
 *	fs/bfs/dir.c
 *	BFS directory operations.
 *	Copyright (C) 1999,2000  Tigran Aivazian <[email protected]>
 *      Made endianness-clean by Andrew Stribblehill <[email protected]> 2005
 */

#include <linux/time.h>
#include <linux/string.h>
#include <linux/fs.h>
#include <linux/buffer_head.h>
#include <linux/sched.h>
#include "bfs.h"

#undef DEBUG

#ifdef DEBUG
#define dprintf(x...)	printf(x)
#else
#define dprintf(x...)
#endif

static int bfs_add_entry(struct inode *dir, const unsigned char *name,
						int namelen, int ino);
static struct buffer_head *bfs_find_entry(struct inode *dir,
				const unsigned char *name, int namelen,
				struct bfs_dirent **res_dir);

static int bfs_readdir(struct file *f, struct dir_context *ctx)
{
	struct inode *dir = file_inode(f);
	struct buffer_head *bh;
	struct bfs_dirent *de;
	unsigned int offset;
	int block;

	if (ctx->pos & (BFS_DIRENT_SIZE - 1)) {
		printf("Bad f_pos=%08lx for %s:%08lx\n",
					(unsigned long)ctx->pos,
					dir->i_sb->s_id, dir->i_ino);
		return -EINVAL;
	}

	while (ctx->pos < dir->i_size) {
		offset = ctx->pos & (BFS_BSIZE - 1);
		block = BFS_I(dir)->i_sblock + (ctx->pos >> BFS_BSIZE_BITS);
		bh = sb_bread(dir->i_sb, block);
		if (!bh) {
			ctx->pos += BFS_BSIZE - offset;
			continue;
		}
		do {
			de = (struct bfs_dirent *)(bh->b_data + offset);
			if (de->ino) {
				int size = strnlen(de->name, BFS_NAMELEN);
				if (!dir_emit(ctx, de->name, size,
						le16_to_cpu(de->ino),
						DT_UNKNOWN)) {
					brelse(bh);
					return 0;
				}
			}
			offset += BFS_DIRENT_SIZE;
			ctx->pos += BFS_DIRENT_SIZE;
		} while ((offset < BFS_BSIZE) && (ctx->pos < dir->i_size));
		brelse(bh);
	}
	return 0;
}

const struct file_operations bfs_dir_operations = {
	.read		= generic_read_dir,
	.iterate	= bfs_readdir,
	.fsync		= generic_file_fsync,
	.llseek		= generic_file_llseek,
};

extern void dump_imap(const char *, struct super_block *);

static int bfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
						bool excl)
{
	int err;
	struct inode *inode;
	struct super_block *s = dir->i_sb;
	struct bfs_sb_info *info = BFS_SB(s);
	unsigned long ino;

	inode = new_inode(s);
	if (!inode)
		return -ENOSPC;
	mutex_lock(&info->bfs_lock);
	ino = find_first_zero_bit(info->si_imap, info->si_lasti + 1);
	if (ino > info->si_lasti) {
		mutex_unlock(&info->bfs_lock);
		iput(inode);
		return -ENOSPC;
	}
	set_bit(ino, info->si_imap);
	info->si_freei--;
	inode_init_owner(inode, dir, mode);
	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
	inode->i_blocks = 0;
	inode->i_op = &bfs_file_inops;
	inode->i_fop = &bfs_file_operations;
	inode->i_mapping->a_ops = &bfs_aops;
	inode->i_ino = ino;
	BFS_I(inode)->i_dsk_ino = ino;
	BFS_I(inode)->i_sblock = 0;
	BFS_I(inode)->i_eblock = 0;
	insert_inode_hash(inode);
        mark_inode_dirty(inode);
	dump_imap("create", s);

	err = bfs_add_entry(dir, dentry->d_name.name, dentry->d_name.len,
							inode->i_ino);
	if (err) {
		inode_dec_link_count(inode);
		mutex_unlock(&info->bfs_lock);
		iput(inode);
		return err;
	}
	mutex_unlock(&info->bfs_lock);
	d_instantiate(dentry, inode);
	return 0;
}

static struct dentry *bfs_lookup(struct inode *dir, struct dentry *dentry,
						unsigned int flags)
{
	struct inode *inode = NULL;
	struct buffer_head *bh;
	struct bfs_dirent *de;
	struct bfs_sb_info *info = BFS_SB(dir->i_sb);

	if (dentry->d_name.len > BFS_NAMELEN)
		return ERR_PTR(-ENAMETOOLONG);

	mutex_lock(&info->bfs_lock);
	bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
	if (bh) {
		unsigned long ino = (unsigned long)le16_to_cpu(de->ino);
		brelse(bh);
		inode = bfs_iget(dir->i_sb, ino);
		if (IS_ERR(inode)) {
			mutex_unlock(&info->bfs_lock);
			return ERR_CAST(inode);
		}
	}
	mutex_unlock(&info->bfs_lock);
	d_add(dentry, inode);
	return NULL;
}

static int bfs_link(struct dentry *old, struct inode *dir,
						struct dentry *new)
{
	struct inode *inode = old->d_inode;
	struct bfs_sb_info *info = BFS_SB(inode->i_sb);
	int err;

	mutex_lock(&info->bfs_lock);
	err = bfs_add_entry(dir, new->d_name.name, new->d_name.len,
							inode->i_ino);
	if (err) {
		mutex_unlock(&info->bfs_lock);
		return err;
	}
	inc_nlink(inode);
	inode->i_ctime = CURRENT_TIME_SEC;
	mark_inode_dirty(inode);
	ihold(inode);
	d_instantiate(new, inode);
	mutex_unlock(&info->bfs_lock);
	return 0;
}

static int bfs_unlink(struct inode *dir, struct dentry *dentry)
{
	int error = -ENOENT;
	struct inode *inode = dentry->d_inode;
	struct buffer_head *bh;
	struct bfs_dirent *de;
	struct bfs_sb_info *info = BFS_SB(inode->i_sb);

	mutex_lock(&info->bfs_lock);
	bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
	if (!bh || (le16_to_cpu(de->ino) != inode->i_ino))
		goto out_brelse;

	if (!inode->i_nlink) {
		printf("unlinking non-existent file %s:%lu (nlink=%d)\n",
					inode->i_sb->s_id, inode->i_ino,
					inode->i_nlink);
		set_nlink(inode, 1);
	}
	de->ino = 0;
	mark_buffer_dirty_inode(bh, dir);
	dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
	mark_inode_dirty(dir);
	inode->i_ctime = dir->i_ctime;
	inode_dec_link_count(inode);
	error = 0;

out_brelse:
	brelse(bh);
	mutex_unlock(&info->bfs_lock);
	return error;
}

static int bfs_rename(struct inode *old_dir, struct dentry *old_dentry,
			struct inode *new_dir, struct dentry *new_dentry)
{
	struct inode *old_inode, *new_inode;
	struct buffer_head *old_bh, *new_bh;
	struct bfs_dirent *old_de, *new_de;
	struct bfs_sb_info *info;
	int error = -ENOENT;

	old_bh = new_bh = NULL;
	old_inode = old_dentry->d_inode;
	if (S_ISDIR(old_inode->i_mode))
		return -EINVAL;

	info = BFS_SB(old_inode->i_sb);

	mutex_lock(&info->bfs_lock);
	old_bh = bfs_find_entry(old_dir, 
				old_dentry->d_name.name, 
				old_dentry->d_name.len, &old_de);

	if (!old_bh || (le16_to_cpu(old_de->ino) != old_inode->i_ino))
		goto end_rename;

	error = -EPERM;
	new_inode = new_dentry->d_inode;
	new_bh = bfs_find_entry(new_dir, 
				new_dentry->d_name.name, 
				new_dentry->d_name.len, &new_de);

	if (new_bh && !new_inode) {
		brelse(new_bh);
		new_bh = NULL;
	}
	if (!new_bh) {
		error = bfs_add_entry(new_dir, 
					new_dentry->d_name.name,
					new_dentry->d_name.len,
					old_inode->i_ino);
		if (error)
			goto end_rename;
	}
	old_de->ino = 0;
	old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
	mark_inode_dirty(old_dir);
	if (new_inode) {
		new_inode->i_ctime = CURRENT_TIME_SEC;
		inode_dec_link_count(new_inode);
	}
	mark_buffer_dirty_inode(old_bh, old_dir);
	error = 0;

end_rename:
	mutex_unlock(&info->bfs_lock);
	brelse(old_bh);
	brelse(new_bh);
	return error;
}

const struct inode_operations bfs_dir_inops = {
	.create			= bfs_create,
	.lookup			= bfs_lookup,
	.link			= bfs_link,
	.unlink			= bfs_unlink,
	.rename			= bfs_rename,
};

static int bfs_add_entry(struct inode *dir, const unsigned char *name,
							int namelen, int ino)
{
	struct buffer_head *bh;
	struct bfs_dirent *de;
	int block, sblock, eblock, off, pos;
	int i;

	dprintf("name=%s, namelen=%d\n", name, namelen);

	if (!namelen)
		return -ENOENT;
	if (namelen > BFS_NAMELEN)
		return -ENAMETOOLONG;

	sblock = BFS_I(dir)->i_sblock;
	eblock = BFS_I(dir)->i_eblock;
	for (block = sblock; block <= eblock; block++) {
		bh = sb_bread(dir->i_sb, block);
		if (!bh)
			return -ENOSPC;
		for (off = 0; off < BFS_BSIZE; off += BFS_DIRENT_SIZE) {
			de = (struct bfs_dirent *)(bh->b_data + off);
			if (!de->ino) {
				pos = (block - sblock) * BFS_BSIZE + off;
				if (pos >= dir->i_size) {
					dir->i_size += BFS_DIRENT_SIZE;
					dir->i_ctime = CURRENT_TIME_SEC;
				}
				dir->i_mtime = CURRENT_TIME_SEC;
				mark_inode_dirty(dir);
				de->ino = cpu_to_le16((u16)ino);
				for (i = 0; i < BFS_NAMELEN; i++)
					de->name[i] =
						(i < namelen) ? name[i] : 0;
				mark_buffer_dirty_inode(bh, dir);
				brelse(bh);
				return 0;
			}
		}
		brelse(bh);
	}
	return -ENOSPC;
}

static inline int bfs_namecmp(int len, const unsigned char *name,
							const char *buffer)
{
	if ((len < BFS_NAMELEN) && buffer[len])
		return 0;
	return !memcmp(name, buffer, len);
}

static struct buffer_head *bfs_find_entry(struct inode *dir,
			const unsigned char *name, int namelen,
			struct bfs_dirent **res_dir)
{
	unsigned long block = 0, offset = 0;
	struct buffer_head *bh = NULL;
	struct bfs_dirent *de;

	*res_dir = NULL;
	if (namelen > BFS_NAMELEN)
		return NULL;

	while (block * BFS_BSIZE + offset < dir->i_size) {
		if (!bh) {
			bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block);
			if (!bh) {
				block++;
				continue;
			}
		}
		de = (struct bfs_dirent *)(bh->b_data + offset);
		offset += BFS_DIRENT_SIZE;
		if (le16_to_cpu(de->ino) &&
				bfs_namecmp(namelen, name, de->name)) {
			*res_dir = de;
			return bh;
		}
		if (offset < bh->b_size)
			continue;
		brelse(bh);
		bh = NULL;
		offset = 0;
		block++;
	}
	brelse(bh);
	return NULL;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* fs/bfs/dir.c
	3	* BFS directory operations.
	4	* Copyright (C) 1999,2000 Tigran Aivazian <[email protected]>
fac92bec	5	* Made endianness-clean by Andrew Stribblehill <[email protected]> 2005
1da177e4 LT	6	*/
	7
	8	#include <linux/time.h>
	9	#include <linux/string.h>
	10	#include <linux/fs.h>
1da177e4 LT	11	#include <linux/buffer_head.h>
	12	#include <linux/sched.h>
	13	#include "bfs.h"
	14
	15	#undef DEBUG
	16
	17	#ifdef DEBUG
	18	#define dprintf(x...) printf(x)
	19	#else
	20	#define dprintf(x...)
	21	#endif
	22
f433dc56 DV	23	static int bfs_add_entry(struct inode dir, const unsigned char name,
	24	int namelen, int ino);
	25	static struct buffer_head bfs_find_entry(struct inode dir,
	26	const unsigned char *name, int namelen,
	27	struct bfs_dirent **res_dir);
1da177e4	28
81b9f66e	29	static int bfs_readdir(struct file f, struct dir_context ctx)
1da177e4	30	{
496ad9aa	31	struct inode *dir = file_inode(f);
f433dc56 DV	32	struct buffer_head *bh;
f433dc56 DV	33	struct bfs_dirent *de;
1da177e4 LT	34	unsigned int offset;
	35	int block;
	36
81b9f66e	37	if (ctx->pos & (BFS_DIRENT_SIZE - 1)) {
f433dc56	38	printf("Bad f_pos=%08lx for %s:%08lx\n",
81b9f66e	39	(unsigned long)ctx->pos,
f433dc56	40	dir->i_sb->s_id, dir->i_ino);
81b9f66e	41	return -EINVAL;
1da177e4 LT	42	}
1da177e4 LT	43
81b9f66e AV	44	while (ctx->pos < dir->i_size) {
	45	offset = ctx->pos & (BFS_BSIZE - 1);
	46	block = BFS_I(dir)->i_sblock + (ctx->pos >> BFS_BSIZE_BITS);
1da177e4 LT	47	bh = sb_bread(dir->i_sb, block);
1da177e4 LT	48	if (!bh) {
81b9f66e	49	ctx->pos += BFS_BSIZE - offset;
1da177e4 LT	50	continue;
	51	}
	52	do {
	53	de = (struct bfs_dirent *)(bh->b_data + offset);
	54	if (de->ino) {
	55	int size = strnlen(de->name, BFS_NAMELEN);
81b9f66e	56	if (!dir_emit(ctx, de->name, size,
f433dc56	57	le16_to_cpu(de->ino),
81b9f66e	58	DT_UNKNOWN)) {
1da177e4	59	brelse(bh);
1da177e4 LT	60	return 0;
	61	}
	62	}
	63	offset += BFS_DIRENT_SIZE;
81b9f66e AV	64	ctx->pos += BFS_DIRENT_SIZE;
81b9f66e AV	65	} while ((offset < BFS_BSIZE) && (ctx->pos < dir->i_size));
1da177e4 LT	66	brelse(bh);
1da177e4 LT	67	}
81b9f66e	68	return 0;
1da177e4 LT	69	}
1da177e4 LT	70
4b6f5d20	71	const struct file_operations bfs_dir_operations = {
1da177e4	72	.read = generic_read_dir,
81b9f66e	73	.iterate = bfs_readdir,
1b061d92	74	.fsync = generic_file_fsync,
3222a3e5	75	.llseek = generic_file_llseek,
1da177e4 LT	76	};
	77
	78	extern void dump_imap(const char , struct super_block );
	79
4acdaf27	80	static int bfs_create(struct inode dir, struct dentry dentry, umode_t mode,
ebfc3b49	81	bool excl)
1da177e4 LT	82	{
1da177e4 LT	83	int err;
f433dc56 DV	84	struct inode *inode;
	85	struct super_block *s = dir->i_sb;
	86	struct bfs_sb_info *info = BFS_SB(s);
1da177e4 LT	87	unsigned long ino;
	88
	89	inode = new_inode(s);
	90	if (!inode)
	91	return -ENOSPC;
3f165e4c	92	mutex_lock(&info->bfs_lock);
69b195be	93	ino = find_first_zero_bit(info->si_imap, info->si_lasti + 1);
1da177e4	94	if (ino > info->si_lasti) {
3f165e4c	95	mutex_unlock(&info->bfs_lock);
1da177e4 LT	96	iput(inode);
	97	return -ENOSPC;
	98	}
f433dc56	99	set_bit(ino, info->si_imap);
1da177e4	100	info->si_freei--;
e6ecdc70	101	inode_init_owner(inode, dir, mode);
1da177e4	102	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
ba52de12	103	inode->i_blocks = 0;
1da177e4 LT	104	inode->i_op = &bfs_file_inops;
	105	inode->i_fop = &bfs_file_operations;
	106	inode->i_mapping->a_ops = &bfs_aops;
1da177e4	107	inode->i_ino = ino;
ce0fe7e7	108	BFS_I(inode)->i_dsk_ino = ino;
1da177e4 LT	109	BFS_I(inode)->i_sblock = 0;
	110	BFS_I(inode)->i_eblock = 0;
	111	insert_inode_hash(inode);
	112	mark_inode_dirty(inode);
f433dc56	113	dump_imap("create", s);
1da177e4	114
f433dc56 DV	115	err = bfs_add_entry(dir, dentry->d_name.name, dentry->d_name.len,
f433dc56 DV	116	inode->i_ino);
1da177e4	117	if (err) {
9a53c3a7	118	inode_dec_link_count(inode);
3f165e4c	119	mutex_unlock(&info->bfs_lock);
1558182f	120	iput(inode);
1da177e4 LT	121	return err;
1da177e4 LT	122	}
3f165e4c	123	mutex_unlock(&info->bfs_lock);
1da177e4 LT	124	d_instantiate(dentry, inode);
	125	return 0;
	126	}
	127
f433dc56	128	static struct dentry bfs_lookup(struct inode dir, struct dentry *dentry,
00cd8dd3	129	unsigned int flags)
1da177e4	130	{
f433dc56 DV	131	struct inode *inode = NULL;
	132	struct buffer_head *bh;
	133	struct bfs_dirent *de;
3f165e4c	134	struct bfs_sb_info *info = BFS_SB(dir->i_sb);
1da177e4 LT	135
	136	if (dentry->d_name.len > BFS_NAMELEN)
	137	return ERR_PTR(-ENAMETOOLONG);
	138
3f165e4c	139	mutex_lock(&info->bfs_lock);
1da177e4 LT	140	bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
1da177e4 LT	141	if (bh) {
fac92bec	142	unsigned long ino = (unsigned long)le16_to_cpu(de->ino);
1da177e4	143	brelse(bh);
e33ab086 DH	144	inode = bfs_iget(dir->i_sb, ino);
e33ab086 DH	145	if (IS_ERR(inode)) {
3f165e4c	146	mutex_unlock(&info->bfs_lock);
e33ab086	147	return ERR_CAST(inode);
1da177e4 LT	148	}
1da177e4 LT	149	}
3f165e4c	150	mutex_unlock(&info->bfs_lock);
1da177e4 LT	151	d_add(dentry, inode);
	152	return NULL;
	153	}
	154
f433dc56 DV	155	static int bfs_link(struct dentry old, struct inode dir,
f433dc56 DV	156	struct dentry *new)
1da177e4	157	{
f433dc56	158	struct inode *inode = old->d_inode;
3f165e4c	159	struct bfs_sb_info *info = BFS_SB(inode->i_sb);
1da177e4 LT	160	int err;
1da177e4 LT	161
3f165e4c	162	mutex_lock(&info->bfs_lock);
f433dc56 DV	163	err = bfs_add_entry(dir, new->d_name.name, new->d_name.len,
f433dc56 DV	164	inode->i_ino);
1da177e4	165	if (err) {
3f165e4c	166	mutex_unlock(&info->bfs_lock);
1da177e4 LT	167	return err;
1da177e4 LT	168	}
d8c76e6f	169	inc_nlink(inode);
1da177e4 LT	170	inode->i_ctime = CURRENT_TIME_SEC;
1da177e4 LT	171	mark_inode_dirty(inode);
7de9c6ee	172	ihold(inode);
1da177e4	173	d_instantiate(new, inode);
3f165e4c	174	mutex_unlock(&info->bfs_lock);
1da177e4 LT	175	return 0;
	176	}
	177
f433dc56	178	static int bfs_unlink(struct inode dir, struct dentry dentry)
1da177e4 LT	179	{
1da177e4 LT	180	int error = -ENOENT;
3f165e4c	181	struct inode *inode = dentry->d_inode;
f433dc56 DV	182	struct buffer_head *bh;
f433dc56 DV	183	struct bfs_dirent *de;
3f165e4c	184	struct bfs_sb_info *info = BFS_SB(inode->i_sb);
1da177e4	185
3f165e4c	186	mutex_lock(&info->bfs_lock);
1da177e4	187	bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
f433dc56	188	if (!bh \|\| (le16_to_cpu(de->ino) != inode->i_ino))
1da177e4 LT	189	goto out_brelse;
	190
	191	if (!inode->i_nlink) {
f433dc56 DV	192	printf("unlinking non-existent file %s:%lu (nlink=%d)\n",
	193	inode->i_sb->s_id, inode->i_ino,
	194	inode->i_nlink);
bfe86848	195	set_nlink(inode, 1);
1da177e4 LT	196	}
1da177e4 LT	197	de->ino = 0;
4427f0c3	198	mark_buffer_dirty_inode(bh, dir);
1da177e4 LT	199	dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
1da177e4 LT	200	mark_inode_dirty(dir);
1da177e4	201	inode->i_ctime = dir->i_ctime;
9a53c3a7	202	inode_dec_link_count(inode);
1da177e4 LT	203	error = 0;
	204
	205	out_brelse:
	206	brelse(bh);
3f165e4c	207	mutex_unlock(&info->bfs_lock);
1da177e4 LT	208	return error;
	209	}
	210
f433dc56 DV	211	static int bfs_rename(struct inode old_dir, struct dentry old_dentry,
f433dc56 DV	212	struct inode new_dir, struct dentry new_dentry)
1da177e4	213	{
f433dc56 DV	214	struct inode old_inode, new_inode;
	215	struct buffer_head old_bh, new_bh;
	216	struct bfs_dirent old_de, new_de;
3f165e4c	217	struct bfs_sb_info *info;
1da177e4 LT	218	int error = -ENOENT;
	219
	220	old_bh = new_bh = NULL;
	221	old_inode = old_dentry->d_inode;
	222	if (S_ISDIR(old_inode->i_mode))
	223	return -EINVAL;
	224
3f165e4c DV	225	info = BFS_SB(old_inode->i_sb);
	226
	227	mutex_lock(&info->bfs_lock);
1da177e4 LT	228	old_bh = bfs_find_entry(old_dir,
	229	old_dentry->d_name.name,
	230	old_dentry->d_name.len, &old_de);
	231
f433dc56	232	if (!old_bh \|\| (le16_to_cpu(old_de->ino) != old_inode->i_ino))
1da177e4 LT	233	goto end_rename;
	234
	235	error = -EPERM;
	236	new_inode = new_dentry->d_inode;
	237	new_bh = bfs_find_entry(new_dir,
	238	new_dentry->d_name.name,
	239	new_dentry->d_name.len, &new_de);
	240
	241	if (new_bh && !new_inode) {
	242	brelse(new_bh);
	243	new_bh = NULL;
	244	}
	245	if (!new_bh) {
	246	error = bfs_add_entry(new_dir,
	247	new_dentry->d_name.name,
f433dc56 DV	248	new_dentry->d_name.len,
f433dc56 DV	249	old_inode->i_ino);
1da177e4 LT	250	if (error)
	251	goto end_rename;
	252	}
	253	old_de->ino = 0;
	254	old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
	255	mark_inode_dirty(old_dir);
	256	if (new_inode) {
1da177e4	257	new_inode->i_ctime = CURRENT_TIME_SEC;
9a53c3a7	258	inode_dec_link_count(new_inode);
1da177e4	259	}
4427f0c3	260	mark_buffer_dirty_inode(old_bh, old_dir);
1da177e4 LT	261	error = 0;
	262
	263	end_rename:
3f165e4c	264	mutex_unlock(&info->bfs_lock);
1da177e4 LT	265	brelse(old_bh);
	266	brelse(new_bh);
	267	return error;
	268	}
	269
754661f1	270	const struct inode_operations bfs_dir_inops = {
1da177e4 LT	271	.create = bfs_create,
	272	.lookup = bfs_lookup,
	273	.link = bfs_link,
	274	.unlink = bfs_unlink,
	275	.rename = bfs_rename,
	276	};
	277
f433dc56 DV	278	static int bfs_add_entry(struct inode dir, const unsigned char name,
f433dc56 DV	279	int namelen, int ino)
1da177e4	280	{
f433dc56 DV	281	struct buffer_head *bh;
	282	struct bfs_dirent *de;
	283	int block, sblock, eblock, off, pos;
1da177e4 LT	284	int i;
	285
	286	dprintf("name=%s, namelen=%d\n", name, namelen);
	287
	288	if (!namelen)
	289	return -ENOENT;
	290	if (namelen > BFS_NAMELEN)
	291	return -ENAMETOOLONG;
	292
	293	sblock = BFS_I(dir)->i_sblock;
	294	eblock = BFS_I(dir)->i_eblock;
f433dc56	295	for (block = sblock; block <= eblock; block++) {
1da177e4	296	bh = sb_bread(dir->i_sb, block);
f433dc56	297	if (!bh)
1da177e4	298	return -ENOSPC;
f433dc56	299	for (off = 0; off < BFS_BSIZE; off += BFS_DIRENT_SIZE) {
1da177e4	300	de = (struct bfs_dirent *)(bh->b_data + off);
1da177e4	301	if (!de->ino) {
f433dc56 DV	302	pos = (block - sblock) * BFS_BSIZE + off;
f433dc56 DV	303	if (pos >= dir->i_size) {
1da177e4 LT	304	dir->i_size += BFS_DIRENT_SIZE;
	305	dir->i_ctime = CURRENT_TIME_SEC;
	306	}
	307	dir->i_mtime = CURRENT_TIME_SEC;
	308	mark_inode_dirty(dir);
fac92bec	309	de->ino = cpu_to_le16((u16)ino);
f433dc56 DV	310	for (i = 0; i < BFS_NAMELEN; i++)
	311	de->name[i] =
	312	(i < namelen) ? name[i] : 0;
4427f0c3	313	mark_buffer_dirty_inode(bh, dir);
1da177e4 LT	314	brelse(bh);
	315	return 0;
	316	}
	317	}
	318	brelse(bh);
	319	}
	320	return -ENOSPC;
	321	}
	322
f433dc56 DV	323	static inline int bfs_namecmp(int len, const unsigned char *name,
f433dc56 DV	324	const char *buffer)
1da177e4	325	{
f433dc56	326	if ((len < BFS_NAMELEN) && buffer[len])
1da177e4 LT	327	return 0;
	328	return !memcmp(name, buffer, len);
	329	}
	330
f433dc56 DV	331	static struct buffer_head bfs_find_entry(struct inode dir,
	332	const unsigned char *name, int namelen,
	333	struct bfs_dirent **res_dir)
1da177e4	334	{
f433dc56 DV	335	unsigned long block = 0, offset = 0;
	336	struct buffer_head *bh = NULL;
	337	struct bfs_dirent *de;
1da177e4 LT	338
	339	*res_dir = NULL;
	340	if (namelen > BFS_NAMELEN)
	341	return NULL;
f433dc56	342
1da177e4 LT	343	while (block * BFS_BSIZE + offset < dir->i_size) {
	344	if (!bh) {
	345	bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block);
	346	if (!bh) {
	347	block++;
	348	continue;
	349	}
	350	}
	351	de = (struct bfs_dirent *)(bh->b_data + offset);
	352	offset += BFS_DIRENT_SIZE;
f433dc56 DV	353	if (le16_to_cpu(de->ino) &&
f433dc56 DV	354	bfs_namecmp(namelen, name, de->name)) {
1da177e4 LT	355	*res_dir = de;
	356	return bh;
	357	}
	358	if (offset < bh->b_size)
	359	continue;
	360	brelse(bh);
	361	bh = NULL;
	362	offset = 0;
	363	block++;
	364	}
	365	brelse(bh);
	366	return NULL;
	367	}