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
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 -ENOSPC;
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_SEC;
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 = old->d_inode;
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_SEC;
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 = dentry->d_inode;
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_SEC;
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{
212	struct inode *old_inode, *new_inode;
213	struct buffer_head *old_bh, *new_bh;
214	struct bfs_dirent *old_de, *new_de;
215	struct bfs_sb_info *info;
216	int error = -ENOENT;
217
218	old_bh = new_bh = NULL;
219	old_inode = old_dentry->d_inode;
220	if (S_ISDIR(old_inode->i_mode))
221		return -EINVAL;
222
223	info = BFS_SB(old_inode->i_sb);
224
225	mutex_lock(&info->bfs_lock);
226	old_bh = bfs_find_entry(old_dir,
227				old_dentry->d_name.name,
228				old_dentry->d_name.len, &old_de);
229
230	if (!old_bh || (le16_to_cpu(old_de->ino) != old_inode->i_ino))
231		goto end_rename;
232
233	error = -EPERM;
234	new_inode = new_dentry->d_inode;
235	new_bh = bfs_find_entry(new_dir,
236				new_dentry->d_name.name,
237				new_dentry->d_name.len, &new_de);
238
239	if (new_bh && !new_inode) {
240		brelse(new_bh);
241		new_bh = NULL;
242	}
243	if (!new_bh) {
244		error = bfs_add_entry(new_dir,
245					new_dentry->d_name.name,
246					new_dentry->d_name.len,
247					old_inode->i_ino);
248		if (error)
249			goto end_rename;
250	}
251	old_de->ino = 0;
252	old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
253	mark_inode_dirty(old_dir);
254	if (new_inode) {
255		new_inode->i_ctime = CURRENT_TIME_SEC;
256		inode_dec_link_count(new_inode);
257	}
258	mark_buffer_dirty_inode(old_bh, old_dir);
259	error = 0;
260
261end_rename:
262	mutex_unlock(&info->bfs_lock);
263	brelse(old_bh);
264	brelse(new_bh);
265	return error;
266}
267
268const struct inode_operations bfs_dir_inops = {
269	.create			= bfs_create,
270	.lookup			= bfs_lookup,
271	.link			= bfs_link,
272	.unlink			= bfs_unlink,
273	.rename			= bfs_rename,
274};
275
276static int bfs_add_entry(struct inode *dir, const unsigned char *name,
277							int namelen, int ino)
278{
279	struct buffer_head *bh;
280	struct bfs_dirent *de;
281	int block, sblock, eblock, off, pos;
282	int i;
283
284	dprintf("name=%s, namelen=%d\n", name, namelen);
285
286	if (!namelen)
287		return -ENOENT;
288	if (namelen > BFS_NAMELEN)
289		return -ENAMETOOLONG;
290
291	sblock = BFS_I(dir)->i_sblock;
292	eblock = BFS_I(dir)->i_eblock;
293	for (block = sblock; block <= eblock; block++) {
294		bh = sb_bread(dir->i_sb, block);
295		if (!bh)
296			return -ENOSPC;
297		for (off = 0; off < BFS_BSIZE; off += BFS_DIRENT_SIZE) {
298			de = (struct bfs_dirent *)(bh->b_data + off);
299			if (!de->ino) {
300				pos = (block - sblock) * BFS_BSIZE + off;
301				if (pos >= dir->i_size) {
302					dir->i_size += BFS_DIRENT_SIZE;
303					dir->i_ctime = CURRENT_TIME_SEC;
304				}
305				dir->i_mtime = CURRENT_TIME_SEC;
306				mark_inode_dirty(dir);
307				de->ino = cpu_to_le16((u16)ino);
308				for (i = 0; i < BFS_NAMELEN; i++)
309					de->name[i] =
310						(i < namelen) ? name[i] : 0;
311				mark_buffer_dirty_inode(bh, dir);
312				brelse(bh);
313				return 0;
314			}
315		}
316		brelse(bh);
317	}
318	return -ENOSPC;
319}
320
321static inline int bfs_namecmp(int len, const unsigned char *name,
322							const char *buffer)
323{
324	if ((len < BFS_NAMELEN) && buffer[len])
325		return 0;
326	return !memcmp(name, buffer, len);
327}
328
329static struct buffer_head *bfs_find_entry(struct inode *dir,
330			const unsigned char *name, int namelen,
331			struct bfs_dirent **res_dir)
332{
333	unsigned long block = 0, offset = 0;
334	struct buffer_head *bh = NULL;
335	struct bfs_dirent *de;
336
337	*res_dir = NULL;
338	if (namelen > BFS_NAMELEN)
339		return NULL;
340
341	while (block * BFS_BSIZE + offset < dir->i_size) {
342		if (!bh) {
343			bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block);
344			if (!bh) {
345				block++;
346				continue;
347			}
348		}
349		de = (struct bfs_dirent *)(bh->b_data + offset);
350		offset += BFS_DIRENT_SIZE;
351		if (le16_to_cpu(de->ino) &&
352				bfs_namecmp(namelen, name, de->name)) {
353			*res_dir = de;
354			return bh;
355		}
356		if (offset < bh->b_size)
357			continue;
358		brelse(bh);
359		bh = NULL;
360		offset = 0;
361		block++;
362	}
363	brelse(bh);
364	return NULL;
365}
366