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

// SPDX-License-Identifier: GPL-2.0
/*
 *	fs/bfs/dir.c
 *	BFS directory operations.
 *	Copyright (C) 1999-2018  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 struct qstr *child, int ino);
static struct buffer_head *bfs_find_entry(struct inode *dir,
				const struct qstr *child,
				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_shared	= bfs_readdir,
	.fsync		= generic_file_fsync,
	.llseek		= generic_file_llseek,
};

static int bfs_create(struct mnt_idmap *idmap, 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 -ENOMEM;
	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(&nop_mnt_idmap, inode, dir, mode);
	simple_inode_init_ts(inode);
	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);
	bfs_dump_imap("create", s);

	err = bfs_add_entry(dir, &dentry->d_name, 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, &de);
	if (bh) {
		unsigned long ino = (unsigned long)le16_to_cpu(de->ino);
		brelse(bh);
		inode = bfs_iget(dir->i_sb, ino);
	}
	mutex_unlock(&info->bfs_lock);
	return d_splice_alias(inode, dentry);
}

static int bfs_link(struct dentry *old, struct inode *dir,
						struct dentry *new)
{
	struct inode *inode = d_inode(old);
	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, inode->i_ino);
	if (err) {
		mutex_unlock(&info->bfs_lock);
		return err;
	}
	inc_nlink(inode);
	inode_set_ctime_current(inode);
	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 = d_inode(dentry);
	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, &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);
	inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
	mark_inode_dirty(dir);
	inode_set_ctime_to_ts(inode, inode_get_ctime(dir));
	inode_dec_link_count(inode);
	error = 0;

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

static int bfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
		      struct dentry *old_dentry, struct inode *new_dir,
		      struct dentry *new_dentry, unsigned int flags)
{
	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;

	if (flags & ~RENAME_NOREPLACE)
		return -EINVAL;

	old_bh = new_bh = NULL;
	old_inode = d_inode(old_dentry);
	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, &old_de);

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

	error = -EPERM;
	new_inode = d_inode(new_dentry);
	new_bh = bfs_find_entry(new_dir, &new_dentry->d_name, &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,
					old_inode->i_ino);
		if (error)
			goto end_rename;
	}
	old_de->ino = 0;
	inode_set_mtime_to_ts(old_dir, inode_set_ctime_current(old_dir));
	mark_inode_dirty(old_dir);
	if (new_inode) {
		inode_set_ctime_current(new_inode);
		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 struct qstr *child, int ino)
{
	const unsigned char *name = child->name;
	int namelen = child->len;
	struct buffer_head *bh;
	struct bfs_dirent *de;
	int block, sblock, eblock, off, pos;
	int i;

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

	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 -EIO;
		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;
					inode_set_ctime_current(dir);
				}
				inode_set_mtime_to_ts(dir,
						      inode_set_ctime_current(dir));
				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 struct qstr *child,
			struct bfs_dirent **res_dir)
{
	unsigned long block = 0, offset = 0;
	struct buffer_head *bh = NULL;
	struct bfs_dirent *de;
	const unsigned char *name = child->name;
	int namelen = child->len;

	*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
b2441318	1	// SPDX-License-Identifier: GPL-2.0
1da177e4 LT	2	/*
	3	* fs/bfs/dir.c
	4	* BFS directory operations.
d1877155 TA	5	* Copyright (C) 1999-2018 Tigran Aivazian <[email protected]>
d1877155 TA	6	* Made endianness-clean by Andrew Stribblehill <[email protected]> 2005
1da177e4 LT	7	*/
	8
	9	#include <linux/time.h>
	10	#include <linux/string.h>
	11	#include <linux/fs.h>
1da177e4 LT	12	#include <linux/buffer_head.h>
	13	#include <linux/sched.h>
	14	#include "bfs.h"
	15
	16	#undef DEBUG
	17
	18	#ifdef DEBUG
	19	#define dprintf(x...) printf(x)
	20	#else
	21	#define dprintf(x...)
	22	#endif
	23
b455ecd4	24	static int bfs_add_entry(struct inode dir, const struct qstr child, int ino);
f433dc56	25	static struct buffer_head bfs_find_entry(struct inode dir,
33ebdebe	26	const struct qstr *child,
f433dc56	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,
c51da20c	73	.iterate_shared = bfs_readdir,
1b061d92	74	.fsync = generic_file_fsync,
3222a3e5	75	.llseek = generic_file_llseek,
1da177e4 LT	76	};
1da177e4 LT	77
6c960e68	78	static int bfs_create(struct mnt_idmap idmap, struct inode dir,
549c7297	79	struct dentry *dentry, umode_t mode, bool excl)
1da177e4 LT	80	{
1da177e4 LT	81	int err;
f433dc56 DV	82	struct inode *inode;
	83	struct super_block *s = dir->i_sb;
	84	struct bfs_sb_info *info = BFS_SB(s);
1da177e4 LT	85	unsigned long ino;
	86
	87	inode = new_inode(s);
	88	if (!inode)
c3fe5872	89	return -ENOMEM;
3f165e4c	90	mutex_lock(&info->bfs_lock);
69b195be	91	ino = find_first_zero_bit(info->si_imap, info->si_lasti + 1);
1da177e4	92	if (ino > info->si_lasti) {
3f165e4c	93	mutex_unlock(&info->bfs_lock);
1da177e4 LT	94	iput(inode);
	95	return -ENOSPC;
	96	}
f433dc56	97	set_bit(ino, info->si_imap);
1da177e4	98	info->si_freei--;
f2d40141	99	inode_init_owner(&nop_mnt_idmap, inode, dir, mode);
ce17a80c	100	simple_inode_init_ts(inode);
ba52de12	101	inode->i_blocks = 0;
1da177e4 LT	102	inode->i_op = &bfs_file_inops;
	103	inode->i_fop = &bfs_file_operations;
	104	inode->i_mapping->a_ops = &bfs_aops;
1da177e4	105	inode->i_ino = ino;
ce0fe7e7	106	BFS_I(inode)->i_dsk_ino = ino;
1da177e4 LT	107	BFS_I(inode)->i_sblock = 0;
	108	BFS_I(inode)->i_eblock = 0;
	109	insert_inode_hash(inode);
	110	mark_inode_dirty(inode);
1da85fdf	111	bfs_dump_imap("create", s);
1da177e4	112
b455ecd4	113	err = bfs_add_entry(dir, &dentry->d_name, inode->i_ino);
1da177e4	114	if (err) {
9a53c3a7	115	inode_dec_link_count(inode);
3f165e4c	116	mutex_unlock(&info->bfs_lock);
1558182f	117	iput(inode);
1da177e4 LT	118	return err;
1da177e4 LT	119	}
3f165e4c	120	mutex_unlock(&info->bfs_lock);
1da177e4 LT	121	d_instantiate(dentry, inode);
	122	return 0;
	123	}
	124
f433dc56	125	static struct dentry bfs_lookup(struct inode dir, struct dentry *dentry,
00cd8dd3	126	unsigned int flags)
1da177e4	127	{
f433dc56 DV	128	struct inode *inode = NULL;
	129	struct buffer_head *bh;
	130	struct bfs_dirent *de;
3f165e4c	131	struct bfs_sb_info *info = BFS_SB(dir->i_sb);
1da177e4 LT	132
	133	if (dentry->d_name.len > BFS_NAMELEN)
	134	return ERR_PTR(-ENAMETOOLONG);
	135
3f165e4c	136	mutex_lock(&info->bfs_lock);
33ebdebe	137	bh = bfs_find_entry(dir, &dentry->d_name, &de);
1da177e4	138	if (bh) {
fac92bec	139	unsigned long ino = (unsigned long)le16_to_cpu(de->ino);
1da177e4	140	brelse(bh);
e33ab086	141	inode = bfs_iget(dir->i_sb, ino);
1da177e4	142	}
3f165e4c	143	mutex_unlock(&info->bfs_lock);
a596a23b	144	return d_splice_alias(inode, dentry);
1da177e4 LT	145	}
1da177e4 LT	146
f433dc56 DV	147	static int bfs_link(struct dentry old, struct inode dir,
f433dc56 DV	148	struct dentry *new)
1da177e4	149	{
2b0143b5	150	struct inode *inode = d_inode(old);
3f165e4c	151	struct bfs_sb_info *info = BFS_SB(inode->i_sb);
1da177e4 LT	152	int err;
1da177e4 LT	153
3f165e4c	154	mutex_lock(&info->bfs_lock);
b455ecd4	155	err = bfs_add_entry(dir, &new->d_name, inode->i_ino);
1da177e4	156	if (err) {
3f165e4c	157	mutex_unlock(&info->bfs_lock);
1da177e4 LT	158	return err;
1da177e4 LT	159	}
d8c76e6f	160	inc_nlink(inode);
73d9b9d0	161	inode_set_ctime_current(inode);
1da177e4	162	mark_inode_dirty(inode);
7de9c6ee	163	ihold(inode);
1da177e4	164	d_instantiate(new, inode);
3f165e4c	165	mutex_unlock(&info->bfs_lock);
1da177e4 LT	166	return 0;
	167	}
	168
f433dc56	169	static int bfs_unlink(struct inode dir, struct dentry dentry)
1da177e4 LT	170	{
1da177e4 LT	171	int error = -ENOENT;
2b0143b5	172	struct inode *inode = d_inode(dentry);
f433dc56 DV	173	struct buffer_head *bh;
f433dc56 DV	174	struct bfs_dirent *de;
3f165e4c	175	struct bfs_sb_info *info = BFS_SB(inode->i_sb);
1da177e4	176
3f165e4c	177	mutex_lock(&info->bfs_lock);
33ebdebe	178	bh = bfs_find_entry(dir, &dentry->d_name, &de);
f433dc56	179	if (!bh \|\| (le16_to_cpu(de->ino) != inode->i_ino))
1da177e4 LT	180	goto out_brelse;
	181
	182	if (!inode->i_nlink) {
f433dc56 DV	183	printf("unlinking non-existent file %s:%lu (nlink=%d)\n",
	184	inode->i_sb->s_id, inode->i_ino,
	185	inode->i_nlink);
bfe86848	186	set_nlink(inode, 1);
1da177e4 LT	187	}
1da177e4 LT	188	de->ino = 0;
4427f0c3	189	mark_buffer_dirty_inode(bh, dir);
ce17a80c	190	inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
1da177e4	191	mark_inode_dirty(dir);
73d9b9d0	192	inode_set_ctime_to_ts(inode, inode_get_ctime(dir));
9a53c3a7	193	inode_dec_link_count(inode);
1da177e4 LT	194	error = 0;
	195
	196	out_brelse:
	197	brelse(bh);
3f165e4c	198	mutex_unlock(&info->bfs_lock);
1da177e4 LT	199	return error;
	200	}
	201
e18275ae	202	static int bfs_rename(struct mnt_idmap idmap, struct inode old_dir,
549c7297 CB	203	struct dentry old_dentry, struct inode new_dir,
549c7297 CB	204	struct dentry *new_dentry, unsigned int flags)
1da177e4	205	{
f433dc56 DV	206	struct inode old_inode, new_inode;
	207	struct buffer_head old_bh, new_bh;
	208	struct bfs_dirent old_de, new_de;
3f165e4c	209	struct bfs_sb_info *info;
1da177e4 LT	210	int error = -ENOENT;
1da177e4 LT	211
f03b8ad8 MS	212	if (flags & ~RENAME_NOREPLACE)
	213	return -EINVAL;
	214
1da177e4	215	old_bh = new_bh = NULL;
2b0143b5	216	old_inode = d_inode(old_dentry);
1da177e4 LT	217	if (S_ISDIR(old_inode->i_mode))
	218	return -EINVAL;
	219
3f165e4c DV	220	info = BFS_SB(old_inode->i_sb);
	221
	222	mutex_lock(&info->bfs_lock);
33ebdebe	223	old_bh = bfs_find_entry(old_dir, &old_dentry->d_name, &old_de);
1da177e4	224
f433dc56	225	if (!old_bh \|\| (le16_to_cpu(old_de->ino) != old_inode->i_ino))
1da177e4 LT	226	goto end_rename;
	227
	228	error = -EPERM;
2b0143b5	229	new_inode = d_inode(new_dentry);
33ebdebe	230	new_bh = bfs_find_entry(new_dir, &new_dentry->d_name, &new_de);
1da177e4 LT	231
	232	if (new_bh && !new_inode) {
	233	brelse(new_bh);
	234	new_bh = NULL;
	235	}
	236	if (!new_bh) {
b455ecd4	237	error = bfs_add_entry(new_dir, &new_dentry->d_name,
f433dc56	238	old_inode->i_ino);
1da177e4 LT	239	if (error)
	240	goto end_rename;
	241	}
	242	old_de->ino = 0;
ce17a80c	243	inode_set_mtime_to_ts(old_dir, inode_set_ctime_current(old_dir));
1da177e4 LT	244	mark_inode_dirty(old_dir);
1da177e4 LT	245	if (new_inode) {
73d9b9d0	246	inode_set_ctime_current(new_inode);
9a53c3a7	247	inode_dec_link_count(new_inode);
1da177e4	248	}
4427f0c3	249	mark_buffer_dirty_inode(old_bh, old_dir);
1da177e4 LT	250	error = 0;
	251
	252	end_rename:
3f165e4c	253	mutex_unlock(&info->bfs_lock);
1da177e4 LT	254	brelse(old_bh);
	255	brelse(new_bh);
	256	return error;
	257	}
	258
754661f1	259	const struct inode_operations bfs_dir_inops = {
1da177e4 LT	260	.create = bfs_create,
	261	.lookup = bfs_lookup,
	262	.link = bfs_link,
	263	.unlink = bfs_unlink,
	264	.rename = bfs_rename,
	265	};
	266
b455ecd4	267	static int bfs_add_entry(struct inode dir, const struct qstr child, int ino)
1da177e4	268	{
b455ecd4 AV	269	const unsigned char *name = child->name;
b455ecd4 AV	270	int namelen = child->len;
f433dc56 DV	271	struct buffer_head *bh;
	272	struct bfs_dirent *de;
	273	int block, sblock, eblock, off, pos;
1da177e4 LT	274	int i;
	275
	276	dprintf("name=%s, namelen=%d\n", name, namelen);
	277
1da177e4 LT	278	sblock = BFS_I(dir)->i_sblock;
1da177e4 LT	279	eblock = BFS_I(dir)->i_eblock;
f433dc56	280	for (block = sblock; block <= eblock; block++) {
1da177e4	281	bh = sb_bread(dir->i_sb, block);
f433dc56	282	if (!bh)
c3fe5872	283	return -EIO;
f433dc56	284	for (off = 0; off < BFS_BSIZE; off += BFS_DIRENT_SIZE) {
1da177e4	285	de = (struct bfs_dirent *)(bh->b_data + off);
1da177e4	286	if (!de->ino) {
f433dc56 DV	287	pos = (block - sblock) * BFS_BSIZE + off;
f433dc56 DV	288	if (pos >= dir->i_size) {
1da177e4	289	dir->i_size += BFS_DIRENT_SIZE;
73d9b9d0	290	inode_set_ctime_current(dir);
1da177e4	291	}
ce17a80c JL	292	inode_set_mtime_to_ts(dir,
ce17a80c JL	293	inode_set_ctime_current(dir));
1da177e4	294	mark_inode_dirty(dir);
fac92bec	295	de->ino = cpu_to_le16((u16)ino);
f433dc56 DV	296	for (i = 0; i < BFS_NAMELEN; i++)
	297	de->name[i] =
	298	(i < namelen) ? name[i] : 0;
4427f0c3	299	mark_buffer_dirty_inode(bh, dir);
1da177e4 LT	300	brelse(bh);
	301	return 0;
	302	}
	303	}
	304	brelse(bh);
	305	}
	306	return -ENOSPC;
	307	}
	308
f433dc56 DV	309	static inline int bfs_namecmp(int len, const unsigned char *name,
f433dc56 DV	310	const char *buffer)
1da177e4	311	{
f433dc56	312	if ((len < BFS_NAMELEN) && buffer[len])
1da177e4 LT	313	return 0;
	314	return !memcmp(name, buffer, len);
	315	}
	316
f433dc56	317	static struct buffer_head bfs_find_entry(struct inode dir,
33ebdebe	318	const struct qstr *child,
f433dc56	319	struct bfs_dirent **res_dir)
1da177e4	320	{
f433dc56 DV	321	unsigned long block = 0, offset = 0;
	322	struct buffer_head *bh = NULL;
	323	struct bfs_dirent *de;
33ebdebe AV	324	const unsigned char *name = child->name;
33ebdebe AV	325	int namelen = child->len;
1da177e4 LT	326
	327	*res_dir = NULL;
	328	if (namelen > BFS_NAMELEN)
	329	return NULL;
f433dc56	330
1da177e4 LT	331	while (block * BFS_BSIZE + offset < dir->i_size) {
	332	if (!bh) {
	333	bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block);
	334	if (!bh) {
	335	block++;
	336	continue;
	337	}
	338	}
	339	de = (struct bfs_dirent *)(bh->b_data + offset);
	340	offset += BFS_DIRENT_SIZE;
f433dc56 DV	341	if (le16_to_cpu(de->ino) &&
f433dc56 DV	342	bfs_namecmp(namelen, name, de->name)) {
1da177e4 LT	343	*res_dir = de;
	344	return bh;
	345	}
	346	if (offset < bh->b_size)
	347	continue;
	348	brelse(bh);
	349	bh = NULL;
	350	offset = 0;
	351	block++;
	352	}
	353	brelse(bh);
	354	return NULL;
	355	}