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v3.15
  1/*
  2 *	fs/bfs/dir.c
  3 *	BFS directory operations.
  4 *	Copyright (C) 1999,2000  Tigran Aivazian <tigran@veritas.com>
  5 *      Made endianness-clean by Andrew Stribblehill <ads@wompom.org> 2005
  6 */
  7
  8#include <linux/time.h>
  9#include <linux/string.h>
 10#include <linux/fs.h>
 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
 23static int bfs_add_entry(struct inode *dir, const unsigned char *name,
 24						int namelen, int ino);
 25static struct buffer_head *bfs_find_entry(struct inode *dir,
 26				const unsigned char *name, int namelen,
 27				struct bfs_dirent **res_dir);
 28
 29static int bfs_readdir(struct file *f, struct dir_context *ctx)
 30{
 31	struct inode *dir = file_inode(f);
 32	struct buffer_head *bh;
 33	struct bfs_dirent *de;
 34	unsigned int offset;
 35	int block;
 36
 37	if (ctx->pos & (BFS_DIRENT_SIZE - 1)) {
 38		printf("Bad f_pos=%08lx for %s:%08lx\n",
 39					(unsigned long)ctx->pos,
 40					dir->i_sb->s_id, dir->i_ino);
 41		return -EINVAL;
 42	}
 43
 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);
 47		bh = sb_bread(dir->i_sb, block);
 48		if (!bh) {
 49			ctx->pos += BFS_BSIZE - offset;
 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);
 56				if (!dir_emit(ctx, de->name, size,
 57						le16_to_cpu(de->ino),
 58						DT_UNKNOWN)) {
 59					brelse(bh);
 60					return 0;
 61				}
 62			}
 63			offset += BFS_DIRENT_SIZE;
 64			ctx->pos += BFS_DIRENT_SIZE;
 65		} while ((offset < BFS_BSIZE) && (ctx->pos < dir->i_size));
 66		brelse(bh);
 67	}
 68	return 0;
 69}
 70
 71const struct file_operations bfs_dir_operations = {
 72	.read		= generic_read_dir,
 73	.iterate	= bfs_readdir,
 74	.fsync		= generic_file_fsync,
 75	.llseek		= generic_file_llseek,
 76};
 77
 78extern void dump_imap(const char *, struct super_block *);
 79
 80static int bfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 81						bool excl)
 82{
 83	int err;
 84	struct inode *inode;
 85	struct super_block *s = dir->i_sb;
 86	struct bfs_sb_info *info = BFS_SB(s);
 87	unsigned long ino;
 88
 89	inode = new_inode(s);
 90	if (!inode)
 91		return -ENOSPC;
 92	mutex_lock(&info->bfs_lock);
 93	ino = find_first_zero_bit(info->si_imap, info->si_lasti + 1);
 94	if (ino > info->si_lasti) {
 95		mutex_unlock(&info->bfs_lock);
 96		iput(inode);
 97		return -ENOSPC;
 98	}
 99	set_bit(ino, info->si_imap);
100	info->si_freei--;
101	inode_init_owner(inode, dir, mode);
102	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
103	inode->i_blocks = 0;
104	inode->i_op = &bfs_file_inops;
105	inode->i_fop = &bfs_file_operations;
106	inode->i_mapping->a_ops = &bfs_aops;
107	inode->i_ino = ino;
108	BFS_I(inode)->i_dsk_ino = ino;
109	BFS_I(inode)->i_sblock = 0;
110	BFS_I(inode)->i_eblock = 0;
111	insert_inode_hash(inode);
112        mark_inode_dirty(inode);
113	dump_imap("create", s);
114
115	err = bfs_add_entry(dir, dentry->d_name.name, dentry->d_name.len,
116							inode->i_ino);
117	if (err) {
118		inode_dec_link_count(inode);
119		mutex_unlock(&info->bfs_lock);
120		iput(inode);
121		return err;
122	}
123	mutex_unlock(&info->bfs_lock);
124	d_instantiate(dentry, inode);
125	return 0;
126}
127
128static struct dentry *bfs_lookup(struct inode *dir, struct dentry *dentry,
129						unsigned int flags)
130{
131	struct inode *inode = NULL;
132	struct buffer_head *bh;
133	struct bfs_dirent *de;
134	struct bfs_sb_info *info = BFS_SB(dir->i_sb);
135
136	if (dentry->d_name.len > BFS_NAMELEN)
137		return ERR_PTR(-ENAMETOOLONG);
138
139	mutex_lock(&info->bfs_lock);
140	bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
141	if (bh) {
142		unsigned long ino = (unsigned long)le16_to_cpu(de->ino);
143		brelse(bh);
144		inode = bfs_iget(dir->i_sb, ino);
145		if (IS_ERR(inode)) {
146			mutex_unlock(&info->bfs_lock);
147			return ERR_CAST(inode);
148		}
149	}
150	mutex_unlock(&info->bfs_lock);
151	d_add(dentry, inode);
152	return NULL;
153}
154
155static int bfs_link(struct dentry *old, struct inode *dir,
156						struct dentry *new)
157{
158	struct inode *inode = old->d_inode;
159	struct bfs_sb_info *info = BFS_SB(inode->i_sb);
160	int err;
161
162	mutex_lock(&info->bfs_lock);
163	err = bfs_add_entry(dir, new->d_name.name, new->d_name.len,
164							inode->i_ino);
165	if (err) {
166		mutex_unlock(&info->bfs_lock);
167		return err;
168	}
169	inc_nlink(inode);
170	inode->i_ctime = CURRENT_TIME_SEC;
171	mark_inode_dirty(inode);
172	ihold(inode);
173	d_instantiate(new, inode);
174	mutex_unlock(&info->bfs_lock);
175	return 0;
176}
177
178static int bfs_unlink(struct inode *dir, struct dentry *dentry)
179{
180	int error = -ENOENT;
181	struct inode *inode = dentry->d_inode;
182	struct buffer_head *bh;
183	struct bfs_dirent *de;
184	struct bfs_sb_info *info = BFS_SB(inode->i_sb);
185
186	mutex_lock(&info->bfs_lock);
187	bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
188	if (!bh || (le16_to_cpu(de->ino) != inode->i_ino))
189		goto out_brelse;
190
191	if (!inode->i_nlink) {
192		printf("unlinking non-existent file %s:%lu (nlink=%d)\n",
193					inode->i_sb->s_id, inode->i_ino,
194					inode->i_nlink);
195		set_nlink(inode, 1);
196	}
197	de->ino = 0;
198	mark_buffer_dirty_inode(bh, dir);
199	dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
200	mark_inode_dirty(dir);
201	inode->i_ctime = dir->i_ctime;
202	inode_dec_link_count(inode);
203	error = 0;
204
205out_brelse:
206	brelse(bh);
207	mutex_unlock(&info->bfs_lock);
208	return error;
209}
210
211static int bfs_rename(struct inode *old_dir, struct dentry *old_dentry,
212			struct inode *new_dir, struct dentry *new_dentry)
 
213{
214	struct inode *old_inode, *new_inode;
215	struct buffer_head *old_bh, *new_bh;
216	struct bfs_dirent *old_de, *new_de;
217	struct bfs_sb_info *info;
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
225	info = BFS_SB(old_inode->i_sb);
226
227	mutex_lock(&info->bfs_lock);
228	old_bh = bfs_find_entry(old_dir, 
229				old_dentry->d_name.name, 
230				old_dentry->d_name.len, &old_de);
231
232	if (!old_bh || (le16_to_cpu(old_de->ino) != old_inode->i_ino))
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,
248					new_dentry->d_name.len,
249					old_inode->i_ino);
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) {
257		new_inode->i_ctime = CURRENT_TIME_SEC;
258		inode_dec_link_count(new_inode);
259	}
260	mark_buffer_dirty_inode(old_bh, old_dir);
261	error = 0;
262
263end_rename:
264	mutex_unlock(&info->bfs_lock);
265	brelse(old_bh);
266	brelse(new_bh);
267	return error;
268}
269
270const struct inode_operations bfs_dir_inops = {
271	.create			= bfs_create,
272	.lookup			= bfs_lookup,
273	.link			= bfs_link,
274	.unlink			= bfs_unlink,
275	.rename			= bfs_rename,
276};
277
278static int bfs_add_entry(struct inode *dir, const unsigned char *name,
279							int namelen, int ino)
280{
281	struct buffer_head *bh;
282	struct bfs_dirent *de;
283	int block, sblock, eblock, off, pos;
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;
295	for (block = sblock; block <= eblock; block++) {
296		bh = sb_bread(dir->i_sb, block);
297		if (!bh)
298			return -ENOSPC;
299		for (off = 0; off < BFS_BSIZE; off += BFS_DIRENT_SIZE) {
300			de = (struct bfs_dirent *)(bh->b_data + off);
301			if (!de->ino) {
302				pos = (block - sblock) * BFS_BSIZE + off;
303				if (pos >= dir->i_size) {
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);
309				de->ino = cpu_to_le16((u16)ino);
310				for (i = 0; i < BFS_NAMELEN; i++)
311					de->name[i] =
312						(i < namelen) ? name[i] : 0;
313				mark_buffer_dirty_inode(bh, dir);
314				brelse(bh);
315				return 0;
316			}
317		}
318		brelse(bh);
319	}
320	return -ENOSPC;
321}
322
323static inline int bfs_namecmp(int len, const unsigned char *name,
324							const char *buffer)
325{
326	if ((len < BFS_NAMELEN) && buffer[len])
327		return 0;
328	return !memcmp(name, buffer, len);
329}
330
331static struct buffer_head *bfs_find_entry(struct inode *dir,
332			const unsigned char *name, int namelen,
333			struct bfs_dirent **res_dir)
334{
335	unsigned long block = 0, offset = 0;
336	struct buffer_head *bh = NULL;
337	struct bfs_dirent *de;
338
339	*res_dir = NULL;
340	if (namelen > BFS_NAMELEN)
341		return NULL;
342
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;
353		if (le16_to_cpu(de->ino) &&
354				bfs_namecmp(namelen, name, de->name)) {
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}
v4.10.11
  1/*
  2 *	fs/bfs/dir.c
  3 *	BFS directory operations.
  4 *	Copyright (C) 1999,2000  Tigran Aivazian <tigran@veritas.com>
  5 *      Made endianness-clean by Andrew Stribblehill <ads@wompom.org> 2005
  6 */
  7
  8#include <linux/time.h>
  9#include <linux/string.h>
 10#include <linux/fs.h>
 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
 23static int bfs_add_entry(struct inode *dir, const unsigned char *name,
 24						int namelen, int ino);
 25static struct buffer_head *bfs_find_entry(struct inode *dir,
 26				const unsigned char *name, int namelen,
 27				struct bfs_dirent **res_dir);
 28
 29static int bfs_readdir(struct file *f, struct dir_context *ctx)
 30{
 31	struct inode *dir = file_inode(f);
 32	struct buffer_head *bh;
 33	struct bfs_dirent *de;
 34	unsigned int offset;
 35	int block;
 36
 37	if (ctx->pos & (BFS_DIRENT_SIZE - 1)) {
 38		printf("Bad f_pos=%08lx for %s:%08lx\n",
 39					(unsigned long)ctx->pos,
 40					dir->i_sb->s_id, dir->i_ino);
 41		return -EINVAL;
 42	}
 43
 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);
 47		bh = sb_bread(dir->i_sb, block);
 48		if (!bh) {
 49			ctx->pos += BFS_BSIZE - offset;
 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);
 56				if (!dir_emit(ctx, de->name, size,
 57						le16_to_cpu(de->ino),
 58						DT_UNKNOWN)) {
 59					brelse(bh);
 60					return 0;
 61				}
 62			}
 63			offset += BFS_DIRENT_SIZE;
 64			ctx->pos += BFS_DIRENT_SIZE;
 65		} while ((offset < BFS_BSIZE) && (ctx->pos < dir->i_size));
 66		brelse(bh);
 67	}
 68	return 0;
 69}
 70
 71const struct file_operations bfs_dir_operations = {
 72	.read		= generic_read_dir,
 73	.iterate_shared	= bfs_readdir,
 74	.fsync		= generic_file_fsync,
 75	.llseek		= generic_file_llseek,
 76};
 77
 
 
 78static int bfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 79						bool excl)
 80{
 81	int err;
 82	struct inode *inode;
 83	struct super_block *s = dir->i_sb;
 84	struct bfs_sb_info *info = BFS_SB(s);
 85	unsigned long ino;
 86
 87	inode = new_inode(s);
 88	if (!inode)
 89		return -ENOMEM;
 90	mutex_lock(&info->bfs_lock);
 91	ino = find_first_zero_bit(info->si_imap, info->si_lasti + 1);
 92	if (ino > info->si_lasti) {
 93		mutex_unlock(&info->bfs_lock);
 94		iput(inode);
 95		return -ENOSPC;
 96	}
 97	set_bit(ino, info->si_imap);
 98	info->si_freei--;
 99	inode_init_owner(inode, dir, mode);
100	inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
101	inode->i_blocks = 0;
102	inode->i_op = &bfs_file_inops;
103	inode->i_fop = &bfs_file_operations;
104	inode->i_mapping->a_ops = &bfs_aops;
105	inode->i_ino = ino;
106	BFS_I(inode)->i_dsk_ino = ino;
107	BFS_I(inode)->i_sblock = 0;
108	BFS_I(inode)->i_eblock = 0;
109	insert_inode_hash(inode);
110        mark_inode_dirty(inode);
111	bfs_dump_imap("create", s);
112
113	err = bfs_add_entry(dir, dentry->d_name.name, dentry->d_name.len,
114							inode->i_ino);
115	if (err) {
116		inode_dec_link_count(inode);
117		mutex_unlock(&info->bfs_lock);
118		iput(inode);
119		return err;
120	}
121	mutex_unlock(&info->bfs_lock);
122	d_instantiate(dentry, inode);
123	return 0;
124}
125
126static struct dentry *bfs_lookup(struct inode *dir, struct dentry *dentry,
127						unsigned int flags)
128{
129	struct inode *inode = NULL;
130	struct buffer_head *bh;
131	struct bfs_dirent *de;
132	struct bfs_sb_info *info = BFS_SB(dir->i_sb);
133
134	if (dentry->d_name.len > BFS_NAMELEN)
135		return ERR_PTR(-ENAMETOOLONG);
136
137	mutex_lock(&info->bfs_lock);
138	bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
139	if (bh) {
140		unsigned long ino = (unsigned long)le16_to_cpu(de->ino);
141		brelse(bh);
142		inode = bfs_iget(dir->i_sb, ino);
143		if (IS_ERR(inode)) {
144			mutex_unlock(&info->bfs_lock);
145			return ERR_CAST(inode);
146		}
147	}
148	mutex_unlock(&info->bfs_lock);
149	d_add(dentry, inode);
150	return NULL;
151}
152
153static int bfs_link(struct dentry *old, struct inode *dir,
154						struct dentry *new)
155{
156	struct inode *inode = d_inode(old);
157	struct bfs_sb_info *info = BFS_SB(inode->i_sb);
158	int err;
159
160	mutex_lock(&info->bfs_lock);
161	err = bfs_add_entry(dir, new->d_name.name, new->d_name.len,
162							inode->i_ino);
163	if (err) {
164		mutex_unlock(&info->bfs_lock);
165		return err;
166	}
167	inc_nlink(inode);
168	inode->i_ctime = current_time(inode);
169	mark_inode_dirty(inode);
170	ihold(inode);
171	d_instantiate(new, inode);
172	mutex_unlock(&info->bfs_lock);
173	return 0;
174}
175
176static int bfs_unlink(struct inode *dir, struct dentry *dentry)
177{
178	int error = -ENOENT;
179	struct inode *inode = d_inode(dentry);
180	struct buffer_head *bh;
181	struct bfs_dirent *de;
182	struct bfs_sb_info *info = BFS_SB(inode->i_sb);
183
184	mutex_lock(&info->bfs_lock);
185	bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
186	if (!bh || (le16_to_cpu(de->ino) != inode->i_ino))
187		goto out_brelse;
188
189	if (!inode->i_nlink) {
190		printf("unlinking non-existent file %s:%lu (nlink=%d)\n",
191					inode->i_sb->s_id, inode->i_ino,
192					inode->i_nlink);
193		set_nlink(inode, 1);
194	}
195	de->ino = 0;
196	mark_buffer_dirty_inode(bh, dir);
197	dir->i_ctime = dir->i_mtime = current_time(dir);
198	mark_inode_dirty(dir);
199	inode->i_ctime = dir->i_ctime;
200	inode_dec_link_count(inode);
201	error = 0;
202
203out_brelse:
204	brelse(bh);
205	mutex_unlock(&info->bfs_lock);
206	return error;
207}
208
209static int bfs_rename(struct inode *old_dir, struct dentry *old_dentry,
210		      struct inode *new_dir, struct dentry *new_dentry,
211		      unsigned int flags)
212{
213	struct inode *old_inode, *new_inode;
214	struct buffer_head *old_bh, *new_bh;
215	struct bfs_dirent *old_de, *new_de;
216	struct bfs_sb_info *info;
217	int error = -ENOENT;
218
219	if (flags & ~RENAME_NOREPLACE)
220		return -EINVAL;
221
222	old_bh = new_bh = NULL;
223	old_inode = d_inode(old_dentry);
224	if (S_ISDIR(old_inode->i_mode))
225		return -EINVAL;
226
227	info = BFS_SB(old_inode->i_sb);
228
229	mutex_lock(&info->bfs_lock);
230	old_bh = bfs_find_entry(old_dir, 
231				old_dentry->d_name.name, 
232				old_dentry->d_name.len, &old_de);
233
234	if (!old_bh || (le16_to_cpu(old_de->ino) != old_inode->i_ino))
235		goto end_rename;
236
237	error = -EPERM;
238	new_inode = d_inode(new_dentry);
239	new_bh = bfs_find_entry(new_dir, 
240				new_dentry->d_name.name, 
241				new_dentry->d_name.len, &new_de);
242
243	if (new_bh && !new_inode) {
244		brelse(new_bh);
245		new_bh = NULL;
246	}
247	if (!new_bh) {
248		error = bfs_add_entry(new_dir, 
249					new_dentry->d_name.name,
250					new_dentry->d_name.len,
251					old_inode->i_ino);
252		if (error)
253			goto end_rename;
254	}
255	old_de->ino = 0;
256	old_dir->i_ctime = old_dir->i_mtime = current_time(old_dir);
257	mark_inode_dirty(old_dir);
258	if (new_inode) {
259		new_inode->i_ctime = current_time(new_inode);
260		inode_dec_link_count(new_inode);
261	}
262	mark_buffer_dirty_inode(old_bh, old_dir);
263	error = 0;
264
265end_rename:
266	mutex_unlock(&info->bfs_lock);
267	brelse(old_bh);
268	brelse(new_bh);
269	return error;
270}
271
272const struct inode_operations bfs_dir_inops = {
273	.create			= bfs_create,
274	.lookup			= bfs_lookup,
275	.link			= bfs_link,
276	.unlink			= bfs_unlink,
277	.rename			= bfs_rename,
278};
279
280static int bfs_add_entry(struct inode *dir, const unsigned char *name,
281							int namelen, int ino)
282{
283	struct buffer_head *bh;
284	struct bfs_dirent *de;
285	int block, sblock, eblock, off, pos;
286	int i;
287
288	dprintf("name=%s, namelen=%d\n", name, namelen);
289
290	if (!namelen)
291		return -ENOENT;
292	if (namelen > BFS_NAMELEN)
293		return -ENAMETOOLONG;
294
295	sblock = BFS_I(dir)->i_sblock;
296	eblock = BFS_I(dir)->i_eblock;
297	for (block = sblock; block <= eblock; block++) {
298		bh = sb_bread(dir->i_sb, block);
299		if (!bh)
300			return -EIO;
301		for (off = 0; off < BFS_BSIZE; off += BFS_DIRENT_SIZE) {
302			de = (struct bfs_dirent *)(bh->b_data + off);
303			if (!de->ino) {
304				pos = (block - sblock) * BFS_BSIZE + off;
305				if (pos >= dir->i_size) {
306					dir->i_size += BFS_DIRENT_SIZE;
307					dir->i_ctime = current_time(dir);
308				}
309				dir->i_mtime = current_time(dir);
310				mark_inode_dirty(dir);
311				de->ino = cpu_to_le16((u16)ino);
312				for (i = 0; i < BFS_NAMELEN; i++)
313					de->name[i] =
314						(i < namelen) ? name[i] : 0;
315				mark_buffer_dirty_inode(bh, dir);
316				brelse(bh);
317				return 0;
318			}
319		}
320		brelse(bh);
321	}
322	return -ENOSPC;
323}
324
325static inline int bfs_namecmp(int len, const unsigned char *name,
326							const char *buffer)
327{
328	if ((len < BFS_NAMELEN) && buffer[len])
329		return 0;
330	return !memcmp(name, buffer, len);
331}
332
333static struct buffer_head *bfs_find_entry(struct inode *dir,
334			const unsigned char *name, int namelen,
335			struct bfs_dirent **res_dir)
336{
337	unsigned long block = 0, offset = 0;
338	struct buffer_head *bh = NULL;
339	struct bfs_dirent *de;
340
341	*res_dir = NULL;
342	if (namelen > BFS_NAMELEN)
343		return NULL;
344
345	while (block * BFS_BSIZE + offset < dir->i_size) {
346		if (!bh) {
347			bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block);
348			if (!bh) {
349				block++;
350				continue;
351			}
352		}
353		de = (struct bfs_dirent *)(bh->b_data + offset);
354		offset += BFS_DIRENT_SIZE;
355		if (le16_to_cpu(de->ino) &&
356				bfs_namecmp(namelen, name, de->name)) {
357			*res_dir = de;
358			return bh;
359		}
360		if (offset < bh->b_size)
361			continue;
362		brelse(bh);
363		bh = NULL;
364		offset = 0;
365		block++;
366	}
367	brelse(bh);
368	return NULL;
369}