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1 | /* |
2 | * OMFS (as used by RIO Karma) directory operations. |
3 | * Copyright (C) 2005 Bob Copeland <me@bobcopeland.com> |
4 | * Released under GPL v2. |
5 | */ |
6 | |
7 | #include <linux/fs.h> |
8 | #include <linux/ctype.h> |
9 | #include <linux/buffer_head.h> |
10 | #include "omfs.h" |
11 | |
12 | static int omfs_hash(const char *name, int namelen, int mod) |
13 | { |
14 | int i, hash = 0; |
15 | for (i = 0; i < namelen; i++) |
16 | hash ^= tolower(name[i]) << (i % 24); |
17 | return hash % mod; |
18 | } |
19 | |
20 | /* |
21 | * Finds the bucket for a given name and reads the containing block; |
22 | * *ofs is set to the offset of the first list entry. |
23 | */ |
24 | static struct buffer_head *omfs_get_bucket(struct inode *dir, |
25 | const char *name, int namelen, int *ofs) |
26 | { |
27 | int nbuckets = (dir->i_size - OMFS_DIR_START)/8; |
28 | int block = clus_to_blk(OMFS_SB(dir->i_sb), dir->i_ino); |
29 | int bucket = omfs_hash(name, namelen, nbuckets); |
30 | |
31 | *ofs = OMFS_DIR_START + bucket * 8; |
32 | return sb_bread(dir->i_sb, block); |
33 | } |
34 | |
35 | static struct buffer_head *omfs_scan_list(struct inode *dir, u64 block, |
36 | const char *name, int namelen, |
37 | u64 *prev_block) |
38 | { |
39 | struct buffer_head *bh; |
40 | struct omfs_inode *oi; |
41 | int err = -ENOENT; |
42 | *prev_block = ~0; |
43 | |
44 | while (block != ~0) { |
45 | bh = sb_bread(dir->i_sb, |
46 | clus_to_blk(OMFS_SB(dir->i_sb), block)); |
47 | if (!bh) { |
48 | err = -EIO; |
49 | goto err; |
50 | } |
51 | |
52 | oi = (struct omfs_inode *) bh->b_data; |
53 | if (omfs_is_bad(OMFS_SB(dir->i_sb), &oi->i_head, block)) { |
54 | brelse(bh); |
55 | goto err; |
56 | } |
57 | |
58 | if (strncmp(oi->i_name, name, namelen) == 0) |
59 | return bh; |
60 | |
61 | *prev_block = block; |
62 | block = be64_to_cpu(oi->i_sibling); |
63 | brelse(bh); |
64 | } |
65 | err: |
66 | return ERR_PTR(err); |
67 | } |
68 | |
69 | static struct buffer_head *omfs_find_entry(struct inode *dir, |
70 | const char *name, int namelen) |
71 | { |
72 | struct buffer_head *bh; |
73 | int ofs; |
74 | u64 block, dummy; |
75 | |
76 | bh = omfs_get_bucket(dir, name, namelen, &ofs); |
77 | if (!bh) |
78 | return ERR_PTR(-EIO); |
79 | |
80 | block = be64_to_cpu(*((__be64 *) &bh->b_data[ofs])); |
81 | brelse(bh); |
82 | |
83 | return omfs_scan_list(dir, block, name, namelen, &dummy); |
84 | } |
85 | |
86 | int omfs_make_empty(struct inode *inode, struct super_block *sb) |
87 | { |
88 | struct omfs_sb_info *sbi = OMFS_SB(sb); |
89 | int block = clus_to_blk(sbi, inode->i_ino); |
90 | struct buffer_head *bh; |
91 | struct omfs_inode *oi; |
92 | |
93 | bh = sb_bread(sb, block); |
94 | if (!bh) |
95 | return -ENOMEM; |
96 | |
97 | memset(bh->b_data, 0, sizeof(struct omfs_inode)); |
98 | |
99 | if (inode->i_mode & S_IFDIR) { |
100 | memset(&bh->b_data[OMFS_DIR_START], 0xff, |
101 | sbi->s_sys_blocksize - OMFS_DIR_START); |
102 | } else |
103 | omfs_make_empty_table(bh, OMFS_EXTENT_START); |
104 | |
105 | oi = (struct omfs_inode *) bh->b_data; |
106 | oi->i_head.h_self = cpu_to_be64(inode->i_ino); |
107 | oi->i_sibling = ~cpu_to_be64(0ULL); |
108 | |
109 | mark_buffer_dirty(bh); |
110 | brelse(bh); |
111 | return 0; |
112 | } |
113 | |
114 | static int omfs_add_link(struct dentry *dentry, struct inode *inode) |
115 | { |
116 | struct inode *dir = dentry->d_parent->d_inode; |
117 | const char *name = dentry->d_name.name; |
118 | int namelen = dentry->d_name.len; |
119 | struct omfs_inode *oi; |
120 | struct buffer_head *bh; |
121 | u64 block; |
122 | __be64 *entry; |
123 | int ofs; |
124 | |
125 | /* just prepend to head of queue in proper bucket */ |
126 | bh = omfs_get_bucket(dir, name, namelen, &ofs); |
127 | if (!bh) |
128 | goto out; |
129 | |
130 | entry = (__be64 *) &bh->b_data[ofs]; |
131 | block = be64_to_cpu(*entry); |
132 | *entry = cpu_to_be64(inode->i_ino); |
133 | mark_buffer_dirty(bh); |
134 | brelse(bh); |
135 | |
136 | /* now set the sibling and parent pointers on the new inode */ |
137 | bh = sb_bread(dir->i_sb, clus_to_blk(OMFS_SB(dir->i_sb), inode->i_ino)); |
138 | if (!bh) |
139 | goto out; |
140 | |
141 | oi = (struct omfs_inode *) bh->b_data; |
142 | memcpy(oi->i_name, name, namelen); |
143 | memset(oi->i_name + namelen, 0, OMFS_NAMELEN - namelen); |
144 | oi->i_sibling = cpu_to_be64(block); |
145 | oi->i_parent = cpu_to_be64(dir->i_ino); |
146 | mark_buffer_dirty(bh); |
147 | brelse(bh); |
148 | |
149 | dir->i_ctime = CURRENT_TIME_SEC; |
150 | |
151 | /* mark affected inodes dirty to rebuild checksums */ |
152 | mark_inode_dirty(dir); |
153 | mark_inode_dirty(inode); |
154 | return 0; |
155 | out: |
156 | return -ENOMEM; |
157 | } |
158 | |
159 | static int omfs_delete_entry(struct dentry *dentry) |
160 | { |
161 | struct inode *dir = dentry->d_parent->d_inode; |
162 | struct inode *dirty; |
163 | const char *name = dentry->d_name.name; |
164 | int namelen = dentry->d_name.len; |
165 | struct omfs_inode *oi; |
166 | struct buffer_head *bh, *bh2; |
167 | __be64 *entry, next; |
168 | u64 block, prev; |
169 | int ofs; |
170 | int err = -ENOMEM; |
171 | |
172 | /* delete the proper node in the bucket's linked list */ |
173 | bh = omfs_get_bucket(dir, name, namelen, &ofs); |
174 | if (!bh) |
175 | goto out; |
176 | |
177 | entry = (__be64 *) &bh->b_data[ofs]; |
178 | block = be64_to_cpu(*entry); |
179 | |
180 | bh2 = omfs_scan_list(dir, block, name, namelen, &prev); |
181 | if (IS_ERR(bh2)) { |
182 | err = PTR_ERR(bh2); |
183 | goto out_free_bh; |
184 | } |
185 | |
186 | oi = (struct omfs_inode *) bh2->b_data; |
187 | next = oi->i_sibling; |
188 | brelse(bh2); |
189 | |
190 | if (prev != ~0) { |
191 | /* found in middle of list, get list ptr */ |
192 | brelse(bh); |
193 | bh = sb_bread(dir->i_sb, |
194 | clus_to_blk(OMFS_SB(dir->i_sb), prev)); |
195 | if (!bh) |
196 | goto out; |
197 | |
198 | oi = (struct omfs_inode *) bh->b_data; |
199 | entry = &oi->i_sibling; |
200 | } |
201 | |
202 | *entry = next; |
203 | mark_buffer_dirty(bh); |
204 | |
205 | if (prev != ~0) { |
206 | dirty = omfs_iget(dir->i_sb, prev); |
207 | if (!IS_ERR(dirty)) { |
208 | mark_inode_dirty(dirty); |
209 | iput(dirty); |
210 | } |
211 | } |
212 | |
213 | err = 0; |
214 | out_free_bh: |
215 | brelse(bh); |
216 | out: |
217 | return err; |
218 | } |
219 | |
220 | static int omfs_dir_is_empty(struct inode *inode) |
221 | { |
222 | int nbuckets = (inode->i_size - OMFS_DIR_START) / 8; |
223 | struct buffer_head *bh; |
224 | u64 *ptr; |
225 | int i; |
226 | |
227 | bh = sb_bread(inode->i_sb, clus_to_blk(OMFS_SB(inode->i_sb), |
228 | inode->i_ino)); |
229 | |
230 | if (!bh) |
231 | return 0; |
232 | |
233 | ptr = (u64 *) &bh->b_data[OMFS_DIR_START]; |
234 | |
235 | for (i = 0; i < nbuckets; i++, ptr++) |
236 | if (*ptr != ~0) |
237 | break; |
238 | |
239 | brelse(bh); |
240 | return *ptr != ~0; |
241 | } |
242 | |
243 | static int omfs_unlink(struct inode *dir, struct dentry *dentry) |
244 | { |
245 | int ret; |
246 | struct inode *inode = dentry->d_inode; |
247 | |
248 | ret = omfs_delete_entry(dentry); |
249 | if (ret) |
250 | goto end_unlink; |
251 | |
252 | inode_dec_link_count(inode); |
253 | mark_inode_dirty(dir); |
254 | |
255 | end_unlink: |
256 | return ret; |
257 | } |
258 | |
259 | static int omfs_rmdir(struct inode *dir, struct dentry *dentry) |
260 | { |
261 | int err = -ENOTEMPTY; |
262 | struct inode *inode = dentry->d_inode; |
263 | |
264 | if (omfs_dir_is_empty(inode)) { |
265 | err = omfs_unlink(dir, dentry); |
266 | if (!err) |
267 | inode_dec_link_count(inode); |
268 | } |
269 | return err; |
270 | } |
271 | |
272 | static int omfs_add_node(struct inode *dir, struct dentry *dentry, int mode) |
273 | { |
274 | int err; |
275 | struct inode *inode = omfs_new_inode(dir, mode); |
276 | |
277 | if (IS_ERR(inode)) |
278 | return PTR_ERR(inode); |
279 | |
280 | err = omfs_make_empty(inode, dir->i_sb); |
281 | if (err) |
282 | goto out_free_inode; |
283 | |
284 | err = omfs_add_link(dentry, inode); |
285 | if (err) |
286 | goto out_free_inode; |
287 | |
288 | d_instantiate(dentry, inode); |
289 | return 0; |
290 | |
291 | out_free_inode: |
292 | iput(inode); |
293 | return err; |
294 | } |
295 | |
296 | static int omfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) |
297 | { |
298 | return omfs_add_node(dir, dentry, mode | S_IFDIR); |
299 | } |
300 | |
301 | static int omfs_create(struct inode *dir, struct dentry *dentry, int mode, |
302 | struct nameidata *nd) |
303 | { |
304 | return omfs_add_node(dir, dentry, mode | S_IFREG); |
305 | } |
306 | |
307 | static struct dentry *omfs_lookup(struct inode *dir, struct dentry *dentry, |
308 | struct nameidata *nd) |
309 | { |
310 | struct buffer_head *bh; |
311 | struct inode *inode = NULL; |
312 | |
313 | if (dentry->d_name.len > OMFS_NAMELEN) |
314 | return ERR_PTR(-ENAMETOOLONG); |
315 | |
316 | bh = omfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len); |
317 | if (!IS_ERR(bh)) { |
318 | struct omfs_inode *oi = (struct omfs_inode *)bh->b_data; |
319 | ino_t ino = be64_to_cpu(oi->i_head.h_self); |
320 | brelse(bh); |
321 | inode = omfs_iget(dir->i_sb, ino); |
322 | if (IS_ERR(inode)) |
323 | return ERR_CAST(inode); |
324 | } |
325 | d_add(dentry, inode); |
326 | return NULL; |
327 | } |
328 | |
329 | /* sanity check block's self pointer */ |
330 | int omfs_is_bad(struct omfs_sb_info *sbi, struct omfs_header *header, |
331 | u64 fsblock) |
332 | { |
333 | int is_bad; |
334 | u64 ino = be64_to_cpu(header->h_self); |
335 | is_bad = ((ino != fsblock) || (ino < sbi->s_root_ino) || |
336 | (ino > sbi->s_num_blocks)); |
337 | |
338 | if (is_bad) |
339 | printk(KERN_WARNING "omfs: bad hash chain detected\n"); |
340 | |
341 | return is_bad; |
342 | } |
343 | |
344 | static int omfs_fill_chain(struct file *filp, void *dirent, filldir_t filldir, |
345 | u64 fsblock, int hindex) |
346 | { |
347 | struct inode *dir = filp->f_dentry->d_inode; |
348 | struct buffer_head *bh; |
349 | struct omfs_inode *oi; |
350 | u64 self; |
351 | int res = 0; |
352 | unsigned char d_type; |
353 | |
354 | /* follow chain in this bucket */ |
355 | while (fsblock != ~0) { |
356 | bh = sb_bread(dir->i_sb, clus_to_blk(OMFS_SB(dir->i_sb), |
357 | fsblock)); |
358 | if (!bh) |
359 | goto out; |
360 | |
361 | oi = (struct omfs_inode *) bh->b_data; |
362 | if (omfs_is_bad(OMFS_SB(dir->i_sb), &oi->i_head, fsblock)) { |
363 | brelse(bh); |
364 | goto out; |
365 | } |
366 | |
367 | self = fsblock; |
368 | fsblock = be64_to_cpu(oi->i_sibling); |
369 | |
370 | /* skip visited nodes */ |
371 | if (hindex) { |
372 | hindex--; |
373 | brelse(bh); |
374 | continue; |
375 | } |
376 | |
377 | d_type = (oi->i_type == OMFS_DIR) ? DT_DIR : DT_REG; |
378 | |
379 | res = filldir(dirent, oi->i_name, strnlen(oi->i_name, |
380 | OMFS_NAMELEN), filp->f_pos, self, d_type); |
381 | if (res == 0) |
382 | filp->f_pos++; |
383 | brelse(bh); |
384 | } |
385 | out: |
386 | return res; |
387 | } |
388 | |
389 | static int omfs_rename(struct inode *old_dir, struct dentry *old_dentry, |
390 | struct inode *new_dir, struct dentry *new_dentry) |
391 | { |
392 | struct inode *new_inode = new_dentry->d_inode; |
393 | struct inode *old_inode = old_dentry->d_inode; |
394 | struct buffer_head *bh; |
395 | int is_dir; |
396 | int err; |
397 | |
398 | is_dir = S_ISDIR(old_inode->i_mode); |
399 | |
400 | if (new_inode) { |
401 | /* overwriting existing file/dir */ |
402 | err = -ENOTEMPTY; |
403 | if (is_dir && !omfs_dir_is_empty(new_inode)) |
404 | goto out; |
405 | |
406 | err = -ENOENT; |
407 | bh = omfs_find_entry(new_dir, new_dentry->d_name.name, |
408 | new_dentry->d_name.len); |
409 | if (IS_ERR(bh)) |
410 | goto out; |
411 | brelse(bh); |
412 | |
413 | err = omfs_unlink(new_dir, new_dentry); |
414 | if (err) |
415 | goto out; |
416 | } |
417 | |
418 | /* since omfs locates files by name, we need to unlink _before_ |
419 | * adding the new link or we won't find the old one */ |
420 | inode_inc_link_count(old_inode); |
421 | err = omfs_unlink(old_dir, old_dentry); |
422 | if (err) { |
423 | inode_dec_link_count(old_inode); |
424 | goto out; |
425 | } |
426 | |
427 | err = omfs_add_link(new_dentry, old_inode); |
428 | if (err) |
429 | goto out; |
430 | |
431 | old_inode->i_ctime = CURRENT_TIME_SEC; |
432 | out: |
433 | return err; |
434 | } |
435 | |
436 | static int omfs_readdir(struct file *filp, void *dirent, filldir_t filldir) |
437 | { |
438 | struct inode *dir = filp->f_dentry->d_inode; |
439 | struct buffer_head *bh; |
440 | loff_t offset, res; |
441 | unsigned int hchain, hindex; |
442 | int nbuckets; |
443 | u64 fsblock; |
444 | int ret = -EINVAL; |
445 | |
446 | if (filp->f_pos >> 32) |
447 | goto success; |
448 | |
449 | switch ((unsigned long) filp->f_pos) { |
450 | case 0: |
451 | if (filldir(dirent, ".", 1, 0, dir->i_ino, DT_DIR) < 0) |
452 | goto success; |
453 | filp->f_pos++; |
454 | /* fall through */ |
455 | case 1: |
456 | if (filldir(dirent, "..", 2, 1, |
457 | parent_ino(filp->f_dentry), DT_DIR) < 0) |
458 | goto success; |
459 | filp->f_pos = 1 << 20; |
460 | /* fall through */ |
461 | } |
462 | |
463 | nbuckets = (dir->i_size - OMFS_DIR_START) / 8; |
464 | |
465 | /* high 12 bits store bucket + 1 and low 20 bits store hash index */ |
466 | hchain = (filp->f_pos >> 20) - 1; |
467 | hindex = filp->f_pos & 0xfffff; |
468 | |
469 | bh = sb_bread(dir->i_sb, clus_to_blk(OMFS_SB(dir->i_sb), dir->i_ino)); |
470 | if (!bh) |
471 | goto out; |
472 | |
473 | offset = OMFS_DIR_START + hchain * 8; |
474 | |
475 | for (; hchain < nbuckets; hchain++, offset += 8) { |
476 | fsblock = be64_to_cpu(*((__be64 *) &bh->b_data[offset])); |
477 | |
478 | res = omfs_fill_chain(filp, dirent, filldir, fsblock, hindex); |
479 | hindex = 0; |
480 | if (res < 0) |
481 | break; |
482 | |
483 | filp->f_pos = (hchain+2) << 20; |
484 | } |
485 | brelse(bh); |
486 | success: |
487 | ret = 0; |
488 | out: |
489 | return ret; |
490 | } |
491 | |
492 | const struct inode_operations omfs_dir_inops = { |
493 | .lookup = omfs_lookup, |
494 | .mkdir = omfs_mkdir, |
495 | .rename = omfs_rename, |
496 | .create = omfs_create, |
497 | .unlink = omfs_unlink, |
498 | .rmdir = omfs_rmdir, |
499 | }; |
500 | |
501 | const struct file_operations omfs_dir_operations = { |
502 | .read = generic_read_dir, |
503 | .readdir = omfs_readdir, |
504 | .llseek = generic_file_llseek, |
505 | }; |
506 |
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