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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 | ||
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); | |
28 | ||
29 | static int bfs_readdir(struct file *f, void *dirent, filldir_t filldir) | |
30 | { | |
31 | struct inode *dir = f->f_path.dentry->d_inode; | |
32 | struct buffer_head *bh; | |
33 | struct bfs_dirent *de; | |
34 | struct bfs_sb_info *info = BFS_SB(dir->i_sb); | |
35 | unsigned int offset; | |
36 | int block; | |
37 | ||
38 | mutex_lock(&info->bfs_lock); | |
39 | ||
40 | if (f->f_pos & (BFS_DIRENT_SIZE - 1)) { | |
41 | printf("Bad f_pos=%08lx for %s:%08lx\n", | |
42 | (unsigned long)f->f_pos, | |
43 | dir->i_sb->s_id, dir->i_ino); | |
44 | mutex_unlock(&info->bfs_lock); | |
45 | return -EBADF; | |
46 | } | |
47 | ||
48 | while (f->f_pos < dir->i_size) { | |
49 | offset = f->f_pos & (BFS_BSIZE - 1); | |
50 | block = BFS_I(dir)->i_sblock + (f->f_pos >> BFS_BSIZE_BITS); | |
51 | bh = sb_bread(dir->i_sb, block); | |
52 | if (!bh) { | |
53 | f->f_pos += BFS_BSIZE - offset; | |
54 | continue; | |
55 | } | |
56 | do { | |
57 | de = (struct bfs_dirent *)(bh->b_data + offset); | |
58 | if (de->ino) { | |
59 | int size = strnlen(de->name, BFS_NAMELEN); | |
60 | if (filldir(dirent, de->name, size, f->f_pos, | |
61 | le16_to_cpu(de->ino), | |
62 | DT_UNKNOWN) < 0) { | |
63 | brelse(bh); | |
64 | mutex_unlock(&info->bfs_lock); | |
65 | return 0; | |
66 | } | |
67 | } | |
68 | offset += BFS_DIRENT_SIZE; | |
69 | f->f_pos += BFS_DIRENT_SIZE; | |
70 | } while ((offset < BFS_BSIZE) && (f->f_pos < dir->i_size)); | |
71 | brelse(bh); | |
72 | } | |
73 | ||
74 | mutex_unlock(&info->bfs_lock); | |
75 | return 0; | |
76 | } | |
77 | ||
78 | const struct file_operations bfs_dir_operations = { | |
79 | .read = generic_read_dir, | |
80 | .readdir = bfs_readdir, | |
81 | .fsync = generic_file_fsync, | |
82 | .llseek = generic_file_llseek, | |
83 | }; | |
84 | ||
85 | extern void dump_imap(const char *, struct super_block *); | |
86 | ||
87 | static int bfs_create(struct inode *dir, struct dentry *dentry, int mode, | |
88 | struct nameidata *nd) | |
89 | { | |
90 | int err; | |
91 | struct inode *inode; | |
92 | struct super_block *s = dir->i_sb; | |
93 | struct bfs_sb_info *info = BFS_SB(s); | |
94 | unsigned long ino; | |
95 | ||
96 | inode = new_inode(s); | |
97 | if (!inode) | |
98 | return -ENOSPC; | |
99 | mutex_lock(&info->bfs_lock); | |
100 | ino = find_first_zero_bit(info->si_imap, info->si_lasti); | |
101 | if (ino > info->si_lasti) { | |
102 | mutex_unlock(&info->bfs_lock); | |
103 | iput(inode); | |
104 | return -ENOSPC; | |
105 | } | |
106 | set_bit(ino, info->si_imap); | |
107 | info->si_freei--; | |
108 | inode_init_owner(inode, dir, mode); | |
109 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC; | |
110 | inode->i_blocks = 0; | |
111 | inode->i_op = &bfs_file_inops; | |
112 | inode->i_fop = &bfs_file_operations; | |
113 | inode->i_mapping->a_ops = &bfs_aops; | |
114 | inode->i_ino = ino; | |
115 | BFS_I(inode)->i_dsk_ino = ino; | |
116 | BFS_I(inode)->i_sblock = 0; | |
117 | BFS_I(inode)->i_eblock = 0; | |
118 | insert_inode_hash(inode); | |
119 | mark_inode_dirty(inode); | |
120 | dump_imap("create", s); | |
121 | ||
122 | err = bfs_add_entry(dir, dentry->d_name.name, dentry->d_name.len, | |
123 | inode->i_ino); | |
124 | if (err) { | |
125 | inode_dec_link_count(inode); | |
126 | mutex_unlock(&info->bfs_lock); | |
127 | iput(inode); | |
128 | return err; | |
129 | } | |
130 | mutex_unlock(&info->bfs_lock); | |
131 | d_instantiate(dentry, inode); | |
132 | return 0; | |
133 | } | |
134 | ||
135 | static struct dentry *bfs_lookup(struct inode *dir, struct dentry *dentry, | |
136 | struct nameidata *nd) | |
137 | { | |
138 | struct inode *inode = NULL; | |
139 | struct buffer_head *bh; | |
140 | struct bfs_dirent *de; | |
141 | struct bfs_sb_info *info = BFS_SB(dir->i_sb); | |
142 | ||
143 | if (dentry->d_name.len > BFS_NAMELEN) | |
144 | return ERR_PTR(-ENAMETOOLONG); | |
145 | ||
146 | mutex_lock(&info->bfs_lock); | |
147 | bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de); | |
148 | if (bh) { | |
149 | unsigned long ino = (unsigned long)le16_to_cpu(de->ino); | |
150 | brelse(bh); | |
151 | inode = bfs_iget(dir->i_sb, ino); | |
152 | if (IS_ERR(inode)) { | |
153 | mutex_unlock(&info->bfs_lock); | |
154 | return ERR_CAST(inode); | |
155 | } | |
156 | } | |
157 | mutex_unlock(&info->bfs_lock); | |
158 | d_add(dentry, inode); | |
159 | return NULL; | |
160 | } | |
161 | ||
162 | static int bfs_link(struct dentry *old, struct inode *dir, | |
163 | struct dentry *new) | |
164 | { | |
165 | struct inode *inode = old->d_inode; | |
166 | struct bfs_sb_info *info = BFS_SB(inode->i_sb); | |
167 | int err; | |
168 | ||
169 | mutex_lock(&info->bfs_lock); | |
170 | err = bfs_add_entry(dir, new->d_name.name, new->d_name.len, | |
171 | inode->i_ino); | |
172 | if (err) { | |
173 | mutex_unlock(&info->bfs_lock); | |
174 | return err; | |
175 | } | |
176 | inc_nlink(inode); | |
177 | inode->i_ctime = CURRENT_TIME_SEC; | |
178 | mark_inode_dirty(inode); | |
179 | atomic_inc(&inode->i_count); | |
180 | d_instantiate(new, inode); | |
181 | mutex_unlock(&info->bfs_lock); | |
182 | return 0; | |
183 | } | |
184 | ||
185 | static int bfs_unlink(struct inode *dir, struct dentry *dentry) | |
186 | { | |
187 | int error = -ENOENT; | |
188 | struct inode *inode = dentry->d_inode; | |
189 | struct buffer_head *bh; | |
190 | struct bfs_dirent *de; | |
191 | struct bfs_sb_info *info = BFS_SB(inode->i_sb); | |
192 | ||
193 | mutex_lock(&info->bfs_lock); | |
194 | bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de); | |
195 | if (!bh || (le16_to_cpu(de->ino) != inode->i_ino)) | |
196 | goto out_brelse; | |
197 | ||
198 | if (!inode->i_nlink) { | |
199 | printf("unlinking non-existent file %s:%lu (nlink=%d)\n", | |
200 | inode->i_sb->s_id, inode->i_ino, | |
201 | inode->i_nlink); | |
202 | inode->i_nlink = 1; | |
203 | } | |
204 | de->ino = 0; | |
205 | mark_buffer_dirty_inode(bh, dir); | |
206 | dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC; | |
207 | mark_inode_dirty(dir); | |
208 | inode->i_ctime = dir->i_ctime; | |
209 | inode_dec_link_count(inode); | |
210 | error = 0; | |
211 | ||
212 | out_brelse: | |
213 | brelse(bh); | |
214 | mutex_unlock(&info->bfs_lock); | |
215 | return error; | |
216 | } | |
217 | ||
218 | static int bfs_rename(struct inode *old_dir, struct dentry *old_dentry, | |
219 | struct inode *new_dir, struct dentry *new_dentry) | |
220 | { | |
221 | struct inode *old_inode, *new_inode; | |
222 | struct buffer_head *old_bh, *new_bh; | |
223 | struct bfs_dirent *old_de, *new_de; | |
224 | struct bfs_sb_info *info; | |
225 | int error = -ENOENT; | |
226 | ||
227 | old_bh = new_bh = NULL; | |
228 | old_inode = old_dentry->d_inode; | |
229 | if (S_ISDIR(old_inode->i_mode)) | |
230 | return -EINVAL; | |
231 | ||
232 | info = BFS_SB(old_inode->i_sb); | |
233 | ||
234 | mutex_lock(&info->bfs_lock); | |
235 | old_bh = bfs_find_entry(old_dir, | |
236 | old_dentry->d_name.name, | |
237 | old_dentry->d_name.len, &old_de); | |
238 | ||
239 | if (!old_bh || (le16_to_cpu(old_de->ino) != old_inode->i_ino)) | |
240 | goto end_rename; | |
241 | ||
242 | error = -EPERM; | |
243 | new_inode = new_dentry->d_inode; | |
244 | new_bh = bfs_find_entry(new_dir, | |
245 | new_dentry->d_name.name, | |
246 | new_dentry->d_name.len, &new_de); | |
247 | ||
248 | if (new_bh && !new_inode) { | |
249 | brelse(new_bh); | |
250 | new_bh = NULL; | |
251 | } | |
252 | if (!new_bh) { | |
253 | error = bfs_add_entry(new_dir, | |
254 | new_dentry->d_name.name, | |
255 | new_dentry->d_name.len, | |
256 | old_inode->i_ino); | |
257 | if (error) | |
258 | goto end_rename; | |
259 | } | |
260 | old_de->ino = 0; | |
261 | old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC; | |
262 | mark_inode_dirty(old_dir); | |
263 | if (new_inode) { | |
264 | new_inode->i_ctime = CURRENT_TIME_SEC; | |
265 | inode_dec_link_count(new_inode); | |
266 | } | |
267 | mark_buffer_dirty_inode(old_bh, old_dir); | |
268 | error = 0; | |
269 | ||
270 | end_rename: | |
271 | mutex_unlock(&info->bfs_lock); | |
272 | brelse(old_bh); | |
273 | brelse(new_bh); | |
274 | return error; | |
275 | } | |
276 | ||
277 | const struct inode_operations bfs_dir_inops = { | |
278 | .create = bfs_create, | |
279 | .lookup = bfs_lookup, | |
280 | .link = bfs_link, | |
281 | .unlink = bfs_unlink, | |
282 | .rename = bfs_rename, | |
283 | }; | |
284 | ||
285 | static int bfs_add_entry(struct inode *dir, const unsigned char *name, | |
286 | int namelen, int ino) | |
287 | { | |
288 | struct buffer_head *bh; | |
289 | struct bfs_dirent *de; | |
290 | int block, sblock, eblock, off, pos; | |
291 | int i; | |
292 | ||
293 | dprintf("name=%s, namelen=%d\n", name, namelen); | |
294 | ||
295 | if (!namelen) | |
296 | return -ENOENT; | |
297 | if (namelen > BFS_NAMELEN) | |
298 | return -ENAMETOOLONG; | |
299 | ||
300 | sblock = BFS_I(dir)->i_sblock; | |
301 | eblock = BFS_I(dir)->i_eblock; | |
302 | for (block = sblock; block <= eblock; block++) { | |
303 | bh = sb_bread(dir->i_sb, block); | |
304 | if (!bh) | |
305 | return -ENOSPC; | |
306 | for (off = 0; off < BFS_BSIZE; off += BFS_DIRENT_SIZE) { | |
307 | de = (struct bfs_dirent *)(bh->b_data + off); | |
308 | if (!de->ino) { | |
309 | pos = (block - sblock) * BFS_BSIZE + off; | |
310 | if (pos >= dir->i_size) { | |
311 | dir->i_size += BFS_DIRENT_SIZE; | |
312 | dir->i_ctime = CURRENT_TIME_SEC; | |
313 | } | |
314 | dir->i_mtime = CURRENT_TIME_SEC; | |
315 | mark_inode_dirty(dir); | |
316 | de->ino = cpu_to_le16((u16)ino); | |
317 | for (i = 0; i < BFS_NAMELEN; i++) | |
318 | de->name[i] = | |
319 | (i < namelen) ? name[i] : 0; | |
320 | mark_buffer_dirty_inode(bh, dir); | |
321 | brelse(bh); | |
322 | return 0; | |
323 | } | |
324 | } | |
325 | brelse(bh); | |
326 | } | |
327 | return -ENOSPC; | |
328 | } | |
329 | ||
330 | static inline int bfs_namecmp(int len, const unsigned char *name, | |
331 | const char *buffer) | |
332 | { | |
333 | if ((len < BFS_NAMELEN) && buffer[len]) | |
334 | return 0; | |
335 | return !memcmp(name, buffer, len); | |
336 | } | |
337 | ||
338 | static struct buffer_head *bfs_find_entry(struct inode *dir, | |
339 | const unsigned char *name, int namelen, | |
340 | struct bfs_dirent **res_dir) | |
341 | { | |
342 | unsigned long block = 0, offset = 0; | |
343 | struct buffer_head *bh = NULL; | |
344 | struct bfs_dirent *de; | |
345 | ||
346 | *res_dir = NULL; | |
347 | if (namelen > BFS_NAMELEN) | |
348 | return NULL; | |
349 | ||
350 | while (block * BFS_BSIZE + offset < dir->i_size) { | |
351 | if (!bh) { | |
352 | bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block); | |
353 | if (!bh) { | |
354 | block++; | |
355 | continue; | |
356 | } | |
357 | } | |
358 | de = (struct bfs_dirent *)(bh->b_data + offset); | |
359 | offset += BFS_DIRENT_SIZE; | |
360 | if (le16_to_cpu(de->ino) && | |
361 | bfs_namecmp(namelen, name, de->name)) { | |
362 | *res_dir = de; | |
363 | return bh; | |
364 | } | |
365 | if (offset < bh->b_size) | |
366 | continue; | |
367 | brelse(bh); | |
368 | bh = NULL; | |
369 | offset = 0; | |
370 | block++; | |
371 | } | |
372 | brelse(bh); | |
373 | return NULL; | |
374 | } |