Commit | Line | Data |
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5db53f3e JE |
1 | /* |
2 | * fs/logfs/dir.c - directory-related code | |
3 | * | |
4 | * As should be obvious for Linux kernel code, license is GPLv2 | |
5 | * | |
6 | * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org> | |
7 | */ | |
8 | #include "logfs.h" | |
9 | ||
10 | ||
11 | /* | |
12 | * Atomic dir operations | |
13 | * | |
14 | * Directory operations are by default not atomic. Dentries and Inodes are | |
15 | * created/removed/altered in seperate operations. Therefore we need to do | |
16 | * a small amount of journaling. | |
17 | * | |
18 | * Create, link, mkdir, mknod and symlink all share the same function to do | |
19 | * the work: __logfs_create. This function works in two atomic steps: | |
20 | * 1. allocate inode (remember in journal) | |
21 | * 2. allocate dentry (clear journal) | |
22 | * | |
23 | * As we can only get interrupted between the two, when the inode we just | |
24 | * created is simply stored in the anchor. On next mount, if we were | |
25 | * interrupted, we delete the inode. From a users point of view the | |
26 | * operation never happened. | |
27 | * | |
28 | * Unlink and rmdir also share the same function: unlink. Again, this | |
29 | * function works in two atomic steps | |
30 | * 1. remove dentry (remember inode in journal) | |
31 | * 2. unlink inode (clear journal) | |
32 | * | |
33 | * And again, on the next mount, if we were interrupted, we delete the inode. | |
34 | * From a users point of view the operation succeeded. | |
35 | * | |
36 | * Rename is the real pain to deal with, harder than all the other methods | |
37 | * combined. Depending on the circumstances we can run into three cases. | |
38 | * A "target rename" where the target dentry already existed, a "local | |
39 | * rename" where both parent directories are identical or a "cross-directory | |
40 | * rename" in the remaining case. | |
41 | * | |
42 | * Local rename is atomic, as the old dentry is simply rewritten with a new | |
43 | * name. | |
44 | * | |
45 | * Cross-directory rename works in two steps, similar to __logfs_create and | |
46 | * logfs_unlink: | |
47 | * 1. Write new dentry (remember old dentry in journal) | |
48 | * 2. Remove old dentry (clear journal) | |
49 | * | |
50 | * Here we remember a dentry instead of an inode. On next mount, if we were | |
51 | * interrupted, we delete the dentry. From a users point of view, the | |
52 | * operation succeeded. | |
53 | * | |
54 | * Target rename works in three atomic steps: | |
55 | * 1. Attach old inode to new dentry (remember old dentry and new inode) | |
56 | * 2. Remove old dentry (still remember the new inode) | |
57 | * 3. Remove victim inode | |
58 | * | |
59 | * Here we remember both an inode an a dentry. If we get interrupted | |
60 | * between steps 1 and 2, we delete both the dentry and the inode. If | |
61 | * we get interrupted between steps 2 and 3, we delete just the inode. | |
62 | * In either case, the remaining objects are deleted on next mount. From | |
63 | * a users point of view, the operation succeeded. | |
64 | */ | |
65 | ||
66 | static int write_dir(struct inode *dir, struct logfs_disk_dentry *dd, | |
67 | loff_t pos) | |
68 | { | |
69 | return logfs_inode_write(dir, dd, sizeof(*dd), pos, WF_LOCK, NULL); | |
70 | } | |
71 | ||
72 | static int write_inode(struct inode *inode) | |
73 | { | |
74 | return __logfs_write_inode(inode, WF_LOCK); | |
75 | } | |
76 | ||
77 | static s64 dir_seek_data(struct inode *inode, s64 pos) | |
78 | { | |
79 | s64 new_pos = logfs_seek_data(inode, pos); | |
80 | ||
81 | return max(pos, new_pos - 1); | |
82 | } | |
83 | ||
84 | static int beyond_eof(struct inode *inode, loff_t bix) | |
85 | { | |
86 | loff_t pos = bix << inode->i_sb->s_blocksize_bits; | |
87 | return pos >= i_size_read(inode); | |
88 | } | |
89 | ||
90 | /* | |
91 | * Prime value was chosen to be roughly 256 + 26. r5 hash uses 11, | |
92 | * so short names (len <= 9) don't even occupy the complete 32bit name | |
93 | * space. A prime >256 ensures short names quickly spread the 32bit | |
94 | * name space. Add about 26 for the estimated amount of information | |
95 | * of each character and pick a prime nearby, preferrably a bit-sparse | |
96 | * one. | |
97 | */ | |
98 | static u32 hash_32(const char *s, int len, u32 seed) | |
99 | { | |
100 | u32 hash = seed; | |
101 | int i; | |
102 | ||
103 | for (i = 0; i < len; i++) | |
104 | hash = hash * 293 + s[i]; | |
105 | return hash; | |
106 | } | |
107 | ||
108 | /* | |
109 | * We have to satisfy several conflicting requirements here. Small | |
110 | * directories should stay fairly compact and not require too many | |
111 | * indirect blocks. The number of possible locations for a given hash | |
112 | * should be small to make lookup() fast. And we should try hard not | |
113 | * to overflow the 32bit name space or nfs and 32bit host systems will | |
114 | * be unhappy. | |
115 | * | |
116 | * So we use the following scheme. First we reduce the hash to 0..15 | |
117 | * and try a direct block. If that is occupied we reduce the hash to | |
118 | * 16..255 and try an indirect block. Same for 2x and 3x indirect | |
119 | * blocks. Lastly we reduce the hash to 0x800_0000 .. 0xffff_ffff, | |
120 | * but use buckets containing eight entries instead of a single one. | |
121 | * | |
122 | * Using 16 entries should allow for a reasonable amount of hash | |
123 | * collisions, so the 32bit name space can be packed fairly tight | |
124 | * before overflowing. Oh and currently we don't overflow but return | |
125 | * and error. | |
126 | * | |
127 | * How likely are collisions? Doing the appropriate math is beyond me | |
128 | * and the Bronstein textbook. But running a test program to brute | |
129 | * force collisions for a couple of days showed that on average the | |
130 | * first collision occurs after 598M entries, with 290M being the | |
131 | * smallest result. Obviously 21 entries could already cause a | |
132 | * collision if all entries are carefully chosen. | |
133 | */ | |
134 | static pgoff_t hash_index(u32 hash, int round) | |
135 | { | |
136 | switch (round) { | |
137 | case 0: | |
138 | return hash % I0_BLOCKS; | |
139 | case 1: | |
140 | return I0_BLOCKS + hash % (I1_BLOCKS - I0_BLOCKS); | |
141 | case 2: | |
142 | return I1_BLOCKS + hash % (I2_BLOCKS - I1_BLOCKS); | |
143 | case 3: | |
144 | return I2_BLOCKS + hash % (I3_BLOCKS - I2_BLOCKS); | |
145 | case 4 ... 19: | |
146 | return I3_BLOCKS + 16 * (hash % (((1<<31) - I3_BLOCKS) / 16)) | |
147 | + round - 4; | |
148 | } | |
149 | BUG(); | |
150 | } | |
151 | ||
152 | static struct page *logfs_get_dd_page(struct inode *dir, struct dentry *dentry) | |
153 | { | |
154 | struct qstr *name = &dentry->d_name; | |
155 | struct page *page; | |
156 | struct logfs_disk_dentry *dd; | |
157 | u32 hash = hash_32(name->name, name->len, 0); | |
158 | pgoff_t index; | |
159 | int round; | |
160 | ||
161 | if (name->len > LOGFS_MAX_NAMELEN) | |
162 | return ERR_PTR(-ENAMETOOLONG); | |
163 | ||
164 | for (round = 0; round < 20; round++) { | |
165 | index = hash_index(hash, round); | |
166 | ||
167 | if (beyond_eof(dir, index)) | |
168 | return NULL; | |
169 | if (!logfs_exist_block(dir, index)) | |
170 | continue; | |
171 | page = read_cache_page(dir->i_mapping, index, | |
172 | (filler_t *)logfs_readpage, NULL); | |
173 | if (IS_ERR(page)) | |
174 | return page; | |
175 | dd = kmap_atomic(page, KM_USER0); | |
176 | BUG_ON(dd->namelen == 0); | |
177 | ||
178 | if (name->len != be16_to_cpu(dd->namelen) || | |
179 | memcmp(name->name, dd->name, name->len)) { | |
180 | kunmap_atomic(dd, KM_USER0); | |
181 | page_cache_release(page); | |
182 | continue; | |
183 | } | |
184 | ||
185 | kunmap_atomic(dd, KM_USER0); | |
186 | return page; | |
187 | } | |
188 | return NULL; | |
189 | } | |
190 | ||
191 | static int logfs_remove_inode(struct inode *inode) | |
192 | { | |
193 | int ret; | |
194 | ||
195 | inode->i_nlink--; | |
196 | ret = write_inode(inode); | |
197 | LOGFS_BUG_ON(ret, inode->i_sb); | |
198 | return ret; | |
199 | } | |
200 | ||
201 | static void abort_transaction(struct inode *inode, struct logfs_transaction *ta) | |
202 | { | |
203 | if (logfs_inode(inode)->li_block) | |
204 | logfs_inode(inode)->li_block->ta = NULL; | |
205 | kfree(ta); | |
206 | } | |
207 | ||
208 | static int logfs_unlink(struct inode *dir, struct dentry *dentry) | |
209 | { | |
210 | struct logfs_super *super = logfs_super(dir->i_sb); | |
211 | struct inode *inode = dentry->d_inode; | |
212 | struct logfs_transaction *ta; | |
213 | struct page *page; | |
214 | pgoff_t index; | |
215 | int ret; | |
216 | ||
217 | ta = kzalloc(sizeof(*ta), GFP_KERNEL); | |
218 | if (!ta) | |
219 | return -ENOMEM; | |
220 | ||
221 | ta->state = UNLINK_1; | |
222 | ta->ino = inode->i_ino; | |
223 | ||
224 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
225 | ||
226 | page = logfs_get_dd_page(dir, dentry); | |
ddfd1f04 JE |
227 | if (!page) { |
228 | kfree(ta); | |
5db53f3e | 229 | return -ENOENT; |
ddfd1f04 JE |
230 | } |
231 | if (IS_ERR(page)) { | |
232 | kfree(ta); | |
5db53f3e | 233 | return PTR_ERR(page); |
ddfd1f04 | 234 | } |
5db53f3e JE |
235 | index = page->index; |
236 | page_cache_release(page); | |
237 | ||
238 | mutex_lock(&super->s_dirop_mutex); | |
239 | logfs_add_transaction(dir, ta); | |
240 | ||
241 | ret = logfs_delete(dir, index, NULL); | |
242 | if (!ret) | |
243 | ret = write_inode(dir); | |
244 | ||
245 | if (ret) { | |
246 | abort_transaction(dir, ta); | |
247 | printk(KERN_ERR"LOGFS: unable to delete inode\n"); | |
248 | goto out; | |
249 | } | |
250 | ||
251 | ta->state = UNLINK_2; | |
252 | logfs_add_transaction(inode, ta); | |
253 | ret = logfs_remove_inode(inode); | |
254 | out: | |
255 | mutex_unlock(&super->s_dirop_mutex); | |
256 | return ret; | |
257 | } | |
258 | ||
259 | static inline int logfs_empty_dir(struct inode *dir) | |
260 | { | |
261 | u64 data; | |
262 | ||
263 | data = logfs_seek_data(dir, 0) << dir->i_sb->s_blocksize_bits; | |
264 | return data >= i_size_read(dir); | |
265 | } | |
266 | ||
267 | static int logfs_rmdir(struct inode *dir, struct dentry *dentry) | |
268 | { | |
269 | struct inode *inode = dentry->d_inode; | |
270 | ||
271 | if (!logfs_empty_dir(inode)) | |
272 | return -ENOTEMPTY; | |
273 | ||
274 | return logfs_unlink(dir, dentry); | |
275 | } | |
276 | ||
277 | /* FIXME: readdir currently has it's own dir_walk code. I don't see a good | |
278 | * way to combine the two copies */ | |
279 | #define IMPLICIT_NODES 2 | |
280 | static int __logfs_readdir(struct file *file, void *buf, filldir_t filldir) | |
281 | { | |
282 | struct inode *dir = file->f_dentry->d_inode; | |
283 | loff_t pos = file->f_pos - IMPLICIT_NODES; | |
284 | struct page *page; | |
285 | struct logfs_disk_dentry *dd; | |
286 | int full; | |
287 | ||
288 | BUG_ON(pos < 0); | |
289 | for (;; pos++) { | |
290 | if (beyond_eof(dir, pos)) | |
291 | break; | |
292 | if (!logfs_exist_block(dir, pos)) { | |
293 | /* deleted dentry */ | |
294 | pos = dir_seek_data(dir, pos); | |
295 | continue; | |
296 | } | |
297 | page = read_cache_page(dir->i_mapping, pos, | |
298 | (filler_t *)logfs_readpage, NULL); | |
299 | if (IS_ERR(page)) | |
300 | return PTR_ERR(page); | |
301 | dd = kmap_atomic(page, KM_USER0); | |
302 | BUG_ON(dd->namelen == 0); | |
303 | ||
304 | full = filldir(buf, (char *)dd->name, be16_to_cpu(dd->namelen), | |
305 | pos, be64_to_cpu(dd->ino), dd->type); | |
306 | kunmap_atomic(dd, KM_USER0); | |
307 | page_cache_release(page); | |
308 | if (full) | |
309 | break; | |
310 | } | |
311 | ||
312 | file->f_pos = pos + IMPLICIT_NODES; | |
313 | return 0; | |
314 | } | |
315 | ||
316 | static int logfs_readdir(struct file *file, void *buf, filldir_t filldir) | |
317 | { | |
318 | struct inode *inode = file->f_dentry->d_inode; | |
319 | ino_t pino = parent_ino(file->f_dentry); | |
320 | int err; | |
321 | ||
322 | if (file->f_pos < 0) | |
323 | return -EINVAL; | |
324 | ||
325 | if (file->f_pos == 0) { | |
326 | if (filldir(buf, ".", 1, 1, inode->i_ino, DT_DIR) < 0) | |
327 | return 0; | |
328 | file->f_pos++; | |
329 | } | |
330 | if (file->f_pos == 1) { | |
331 | if (filldir(buf, "..", 2, 2, pino, DT_DIR) < 0) | |
332 | return 0; | |
333 | file->f_pos++; | |
334 | } | |
335 | ||
336 | err = __logfs_readdir(file, buf, filldir); | |
337 | return err; | |
338 | } | |
339 | ||
340 | static void logfs_set_name(struct logfs_disk_dentry *dd, struct qstr *name) | |
341 | { | |
342 | dd->namelen = cpu_to_be16(name->len); | |
343 | memcpy(dd->name, name->name, name->len); | |
344 | } | |
345 | ||
346 | static struct dentry *logfs_lookup(struct inode *dir, struct dentry *dentry, | |
347 | struct nameidata *nd) | |
348 | { | |
349 | struct page *page; | |
350 | struct logfs_disk_dentry *dd; | |
351 | pgoff_t index; | |
352 | u64 ino = 0; | |
353 | struct inode *inode; | |
354 | ||
355 | page = logfs_get_dd_page(dir, dentry); | |
356 | if (IS_ERR(page)) | |
357 | return ERR_CAST(page); | |
358 | if (!page) { | |
359 | d_add(dentry, NULL); | |
360 | return NULL; | |
361 | } | |
362 | index = page->index; | |
363 | dd = kmap_atomic(page, KM_USER0); | |
364 | ino = be64_to_cpu(dd->ino); | |
365 | kunmap_atomic(dd, KM_USER0); | |
366 | page_cache_release(page); | |
367 | ||
368 | inode = logfs_iget(dir->i_sb, ino); | |
369 | if (IS_ERR(inode)) { | |
370 | printk(KERN_ERR"LogFS: Cannot read inode #%llx for dentry (%lx, %lx)n", | |
371 | ino, dir->i_ino, index); | |
372 | return ERR_CAST(inode); | |
373 | } | |
374 | return d_splice_alias(inode, dentry); | |
375 | } | |
376 | ||
377 | static void grow_dir(struct inode *dir, loff_t index) | |
378 | { | |
379 | index = (index + 1) << dir->i_sb->s_blocksize_bits; | |
380 | if (i_size_read(dir) < index) | |
381 | i_size_write(dir, index); | |
382 | } | |
383 | ||
384 | static int logfs_write_dir(struct inode *dir, struct dentry *dentry, | |
385 | struct inode *inode) | |
386 | { | |
387 | struct page *page; | |
388 | struct logfs_disk_dentry *dd; | |
389 | u32 hash = hash_32(dentry->d_name.name, dentry->d_name.len, 0); | |
390 | pgoff_t index; | |
391 | int round, err; | |
392 | ||
393 | for (round = 0; round < 20; round++) { | |
394 | index = hash_index(hash, round); | |
395 | ||
396 | if (logfs_exist_block(dir, index)) | |
397 | continue; | |
398 | page = find_or_create_page(dir->i_mapping, index, GFP_KERNEL); | |
399 | if (!page) | |
400 | return -ENOMEM; | |
401 | ||
402 | dd = kmap_atomic(page, KM_USER0); | |
403 | memset(dd, 0, sizeof(*dd)); | |
404 | dd->ino = cpu_to_be64(inode->i_ino); | |
405 | dd->type = logfs_type(inode); | |
406 | logfs_set_name(dd, &dentry->d_name); | |
407 | kunmap_atomic(dd, KM_USER0); | |
408 | ||
409 | err = logfs_write_buf(dir, page, WF_LOCK); | |
410 | unlock_page(page); | |
411 | page_cache_release(page); | |
412 | if (!err) | |
413 | grow_dir(dir, index); | |
414 | return err; | |
415 | } | |
416 | /* FIXME: Is there a better return value? In most cases neither | |
417 | * the filesystem nor the directory are full. But we have had | |
418 | * too many collisions for this particular hash and no fallback. | |
419 | */ | |
420 | return -ENOSPC; | |
421 | } | |
422 | ||
423 | static int __logfs_create(struct inode *dir, struct dentry *dentry, | |
424 | struct inode *inode, const char *dest, long destlen) | |
425 | { | |
426 | struct logfs_super *super = logfs_super(dir->i_sb); | |
427 | struct logfs_inode *li = logfs_inode(inode); | |
428 | struct logfs_transaction *ta; | |
429 | int ret; | |
430 | ||
431 | ta = kzalloc(sizeof(*ta), GFP_KERNEL); | |
432 | if (!ta) | |
433 | return -ENOMEM; | |
434 | ||
435 | ta->state = CREATE_1; | |
436 | ta->ino = inode->i_ino; | |
437 | mutex_lock(&super->s_dirop_mutex); | |
438 | logfs_add_transaction(inode, ta); | |
439 | ||
440 | if (dest) { | |
441 | /* symlink */ | |
442 | ret = logfs_inode_write(inode, dest, destlen, 0, WF_LOCK, NULL); | |
443 | if (!ret) | |
444 | ret = write_inode(inode); | |
445 | } else { | |
446 | /* creat/mkdir/mknod */ | |
447 | ret = write_inode(inode); | |
448 | } | |
449 | if (ret) { | |
450 | abort_transaction(inode, ta); | |
451 | li->li_flags |= LOGFS_IF_STILLBORN; | |
452 | /* FIXME: truncate symlink */ | |
453 | inode->i_nlink--; | |
454 | iput(inode); | |
455 | goto out; | |
456 | } | |
457 | ||
458 | ta->state = CREATE_2; | |
459 | logfs_add_transaction(dir, ta); | |
460 | ret = logfs_write_dir(dir, dentry, inode); | |
461 | /* sync directory */ | |
462 | if (!ret) | |
463 | ret = write_inode(dir); | |
464 | ||
465 | if (ret) { | |
466 | logfs_del_transaction(dir, ta); | |
467 | ta->state = CREATE_2; | |
468 | logfs_add_transaction(inode, ta); | |
469 | logfs_remove_inode(inode); | |
470 | iput(inode); | |
471 | goto out; | |
472 | } | |
473 | d_instantiate(dentry, inode); | |
474 | out: | |
475 | mutex_unlock(&super->s_dirop_mutex); | |
476 | return ret; | |
477 | } | |
478 | ||
479 | static int logfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) | |
480 | { | |
481 | struct inode *inode; | |
482 | ||
483 | /* | |
484 | * FIXME: why do we have to fill in S_IFDIR, while the mode is | |
485 | * correct for mknod, creat, etc.? Smells like the vfs *should* | |
486 | * do it for us but for some reason fails to do so. | |
487 | */ | |
488 | inode = logfs_new_inode(dir, S_IFDIR | mode); | |
489 | if (IS_ERR(inode)) | |
490 | return PTR_ERR(inode); | |
491 | ||
492 | inode->i_op = &logfs_dir_iops; | |
493 | inode->i_fop = &logfs_dir_fops; | |
494 | ||
495 | return __logfs_create(dir, dentry, inode, NULL, 0); | |
496 | } | |
497 | ||
498 | static int logfs_create(struct inode *dir, struct dentry *dentry, int mode, | |
499 | struct nameidata *nd) | |
500 | { | |
501 | struct inode *inode; | |
502 | ||
503 | inode = logfs_new_inode(dir, mode); | |
504 | if (IS_ERR(inode)) | |
505 | return PTR_ERR(inode); | |
506 | ||
507 | inode->i_op = &logfs_reg_iops; | |
508 | inode->i_fop = &logfs_reg_fops; | |
509 | inode->i_mapping->a_ops = &logfs_reg_aops; | |
510 | ||
511 | return __logfs_create(dir, dentry, inode, NULL, 0); | |
512 | } | |
513 | ||
514 | static int logfs_mknod(struct inode *dir, struct dentry *dentry, int mode, | |
515 | dev_t rdev) | |
516 | { | |
517 | struct inode *inode; | |
518 | ||
519 | if (dentry->d_name.len > LOGFS_MAX_NAMELEN) | |
520 | return -ENAMETOOLONG; | |
521 | ||
522 | inode = logfs_new_inode(dir, mode); | |
523 | if (IS_ERR(inode)) | |
524 | return PTR_ERR(inode); | |
525 | ||
526 | init_special_inode(inode, mode, rdev); | |
527 | ||
528 | return __logfs_create(dir, dentry, inode, NULL, 0); | |
529 | } | |
530 | ||
531 | static int logfs_symlink(struct inode *dir, struct dentry *dentry, | |
532 | const char *target) | |
533 | { | |
534 | struct inode *inode; | |
535 | size_t destlen = strlen(target) + 1; | |
536 | ||
537 | if (destlen > dir->i_sb->s_blocksize) | |
538 | return -ENAMETOOLONG; | |
539 | ||
540 | inode = logfs_new_inode(dir, S_IFLNK | 0777); | |
541 | if (IS_ERR(inode)) | |
542 | return PTR_ERR(inode); | |
543 | ||
544 | inode->i_op = &logfs_symlink_iops; | |
545 | inode->i_mapping->a_ops = &logfs_reg_aops; | |
546 | ||
547 | return __logfs_create(dir, dentry, inode, target, destlen); | |
548 | } | |
549 | ||
550 | static int logfs_permission(struct inode *inode, int mask) | |
551 | { | |
552 | return generic_permission(inode, mask, NULL); | |
553 | } | |
554 | ||
555 | static int logfs_link(struct dentry *old_dentry, struct inode *dir, | |
556 | struct dentry *dentry) | |
557 | { | |
558 | struct inode *inode = old_dentry->d_inode; | |
559 | ||
560 | if (inode->i_nlink >= LOGFS_LINK_MAX) | |
561 | return -EMLINK; | |
562 | ||
563 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
564 | atomic_inc(&inode->i_count); | |
565 | inode->i_nlink++; | |
566 | mark_inode_dirty_sync(inode); | |
567 | ||
568 | return __logfs_create(dir, dentry, inode, NULL, 0); | |
569 | } | |
570 | ||
571 | static int logfs_get_dd(struct inode *dir, struct dentry *dentry, | |
572 | struct logfs_disk_dentry *dd, loff_t *pos) | |
573 | { | |
574 | struct page *page; | |
575 | void *map; | |
576 | ||
577 | page = logfs_get_dd_page(dir, dentry); | |
578 | if (IS_ERR(page)) | |
579 | return PTR_ERR(page); | |
580 | *pos = page->index; | |
581 | map = kmap_atomic(page, KM_USER0); | |
582 | memcpy(dd, map, sizeof(*dd)); | |
583 | kunmap_atomic(map, KM_USER0); | |
584 | page_cache_release(page); | |
585 | return 0; | |
586 | } | |
587 | ||
588 | static int logfs_delete_dd(struct inode *dir, loff_t pos) | |
589 | { | |
590 | /* | |
591 | * Getting called with pos somewhere beyond eof is either a goofup | |
592 | * within this file or means someone maliciously edited the | |
593 | * (crc-protected) journal. | |
594 | */ | |
595 | BUG_ON(beyond_eof(dir, pos)); | |
596 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
597 | log_dir(" Delete dentry (%lx, %llx)\n", dir->i_ino, pos); | |
598 | return logfs_delete(dir, pos, NULL); | |
599 | } | |
600 | ||
601 | /* | |
602 | * Cross-directory rename, target does not exist. Just a little nasty. | |
603 | * Create a new dentry in the target dir, then remove the old dentry, | |
604 | * all the while taking care to remember our operation in the journal. | |
605 | */ | |
606 | static int logfs_rename_cross(struct inode *old_dir, struct dentry *old_dentry, | |
607 | struct inode *new_dir, struct dentry *new_dentry) | |
608 | { | |
609 | struct logfs_super *super = logfs_super(old_dir->i_sb); | |
610 | struct logfs_disk_dentry dd; | |
611 | struct logfs_transaction *ta; | |
612 | loff_t pos; | |
613 | int err; | |
614 | ||
615 | /* 1. locate source dd */ | |
616 | err = logfs_get_dd(old_dir, old_dentry, &dd, &pos); | |
617 | if (err) | |
618 | return err; | |
619 | ||
620 | ta = kzalloc(sizeof(*ta), GFP_KERNEL); | |
621 | if (!ta) | |
622 | return -ENOMEM; | |
623 | ||
624 | ta->state = CROSS_RENAME_1; | |
625 | ta->dir = old_dir->i_ino; | |
626 | ta->pos = pos; | |
627 | ||
628 | /* 2. write target dd */ | |
629 | mutex_lock(&super->s_dirop_mutex); | |
630 | logfs_add_transaction(new_dir, ta); | |
631 | err = logfs_write_dir(new_dir, new_dentry, old_dentry->d_inode); | |
632 | if (!err) | |
633 | err = write_inode(new_dir); | |
634 | ||
635 | if (err) { | |
636 | super->s_rename_dir = 0; | |
637 | super->s_rename_pos = 0; | |
638 | abort_transaction(new_dir, ta); | |
639 | goto out; | |
640 | } | |
641 | ||
642 | /* 3. remove source dd */ | |
643 | ta->state = CROSS_RENAME_2; | |
644 | logfs_add_transaction(old_dir, ta); | |
645 | err = logfs_delete_dd(old_dir, pos); | |
646 | if (!err) | |
647 | err = write_inode(old_dir); | |
648 | LOGFS_BUG_ON(err, old_dir->i_sb); | |
649 | out: | |
650 | mutex_unlock(&super->s_dirop_mutex); | |
651 | return err; | |
652 | } | |
653 | ||
654 | static int logfs_replace_inode(struct inode *dir, struct dentry *dentry, | |
655 | struct logfs_disk_dentry *dd, struct inode *inode) | |
656 | { | |
657 | loff_t pos; | |
658 | int err; | |
659 | ||
660 | err = logfs_get_dd(dir, dentry, dd, &pos); | |
661 | if (err) | |
662 | return err; | |
663 | dd->ino = cpu_to_be64(inode->i_ino); | |
664 | dd->type = logfs_type(inode); | |
665 | ||
666 | err = write_dir(dir, dd, pos); | |
667 | if (err) | |
668 | return err; | |
669 | log_dir("Replace dentry (%lx, %llx) %s -> %llx\n", dir->i_ino, pos, | |
670 | dd->name, be64_to_cpu(dd->ino)); | |
671 | return write_inode(dir); | |
672 | } | |
673 | ||
674 | /* Target dentry exists - the worst case. We need to attach the source | |
675 | * inode to the target dentry, then remove the orphaned target inode and | |
676 | * source dentry. | |
677 | */ | |
678 | static int logfs_rename_target(struct inode *old_dir, struct dentry *old_dentry, | |
679 | struct inode *new_dir, struct dentry *new_dentry) | |
680 | { | |
681 | struct logfs_super *super = logfs_super(old_dir->i_sb); | |
682 | struct inode *old_inode = old_dentry->d_inode; | |
683 | struct inode *new_inode = new_dentry->d_inode; | |
684 | int isdir = S_ISDIR(old_inode->i_mode); | |
685 | struct logfs_disk_dentry dd; | |
686 | struct logfs_transaction *ta; | |
687 | loff_t pos; | |
688 | int err; | |
689 | ||
690 | BUG_ON(isdir != S_ISDIR(new_inode->i_mode)); | |
691 | if (isdir) { | |
692 | if (!logfs_empty_dir(new_inode)) | |
693 | return -ENOTEMPTY; | |
694 | } | |
695 | ||
696 | /* 1. locate source dd */ | |
697 | err = logfs_get_dd(old_dir, old_dentry, &dd, &pos); | |
698 | if (err) | |
699 | return err; | |
700 | ||
701 | ta = kzalloc(sizeof(*ta), GFP_KERNEL); | |
702 | if (!ta) | |
703 | return -ENOMEM; | |
704 | ||
705 | ta->state = TARGET_RENAME_1; | |
706 | ta->dir = old_dir->i_ino; | |
707 | ta->pos = pos; | |
708 | ta->ino = new_inode->i_ino; | |
709 | ||
710 | /* 2. attach source inode to target dd */ | |
711 | mutex_lock(&super->s_dirop_mutex); | |
712 | logfs_add_transaction(new_dir, ta); | |
713 | err = logfs_replace_inode(new_dir, new_dentry, &dd, old_inode); | |
714 | if (err) { | |
715 | super->s_rename_dir = 0; | |
716 | super->s_rename_pos = 0; | |
717 | super->s_victim_ino = 0; | |
718 | abort_transaction(new_dir, ta); | |
719 | goto out; | |
720 | } | |
721 | ||
722 | /* 3. remove source dd */ | |
723 | ta->state = TARGET_RENAME_2; | |
724 | logfs_add_transaction(old_dir, ta); | |
725 | err = logfs_delete_dd(old_dir, pos); | |
726 | if (!err) | |
727 | err = write_inode(old_dir); | |
728 | LOGFS_BUG_ON(err, old_dir->i_sb); | |
729 | ||
730 | /* 4. remove target inode */ | |
731 | ta->state = TARGET_RENAME_3; | |
732 | logfs_add_transaction(new_inode, ta); | |
733 | err = logfs_remove_inode(new_inode); | |
734 | ||
735 | out: | |
736 | mutex_unlock(&super->s_dirop_mutex); | |
737 | return err; | |
738 | } | |
739 | ||
740 | static int logfs_rename(struct inode *old_dir, struct dentry *old_dentry, | |
741 | struct inode *new_dir, struct dentry *new_dentry) | |
742 | { | |
743 | if (new_dentry->d_inode) | |
744 | return logfs_rename_target(old_dir, old_dentry, | |
745 | new_dir, new_dentry); | |
746 | return logfs_rename_cross(old_dir, old_dentry, new_dir, new_dentry); | |
747 | } | |
748 | ||
749 | /* No locking done here, as this is called before .get_sb() returns. */ | |
750 | int logfs_replay_journal(struct super_block *sb) | |
751 | { | |
752 | struct logfs_super *super = logfs_super(sb); | |
753 | struct inode *inode; | |
754 | u64 ino, pos; | |
755 | int err; | |
756 | ||
757 | if (super->s_victim_ino) { | |
758 | /* delete victim inode */ | |
759 | ino = super->s_victim_ino; | |
760 | printk(KERN_INFO"LogFS: delete unmapped inode #%llx\n", ino); | |
761 | inode = logfs_iget(sb, ino); | |
762 | if (IS_ERR(inode)) | |
763 | goto fail; | |
764 | ||
765 | LOGFS_BUG_ON(i_size_read(inode) > 0, sb); | |
766 | super->s_victim_ino = 0; | |
767 | err = logfs_remove_inode(inode); | |
768 | iput(inode); | |
769 | if (err) { | |
770 | super->s_victim_ino = ino; | |
771 | goto fail; | |
772 | } | |
773 | } | |
774 | if (super->s_rename_dir) { | |
775 | /* delete old dd from rename */ | |
776 | ino = super->s_rename_dir; | |
777 | pos = super->s_rename_pos; | |
778 | printk(KERN_INFO"LogFS: delete unbacked dentry (%llx, %llx)\n", | |
779 | ino, pos); | |
780 | inode = logfs_iget(sb, ino); | |
781 | if (IS_ERR(inode)) | |
782 | goto fail; | |
783 | ||
784 | super->s_rename_dir = 0; | |
785 | super->s_rename_pos = 0; | |
786 | err = logfs_delete_dd(inode, pos); | |
787 | iput(inode); | |
788 | if (err) { | |
789 | super->s_rename_dir = ino; | |
790 | super->s_rename_pos = pos; | |
791 | goto fail; | |
792 | } | |
793 | } | |
794 | return 0; | |
795 | fail: | |
796 | LOGFS_BUG(sb); | |
797 | return -EIO; | |
798 | } | |
799 | ||
800 | const struct inode_operations logfs_symlink_iops = { | |
801 | .readlink = generic_readlink, | |
802 | .follow_link = page_follow_link_light, | |
803 | }; | |
804 | ||
805 | const struct inode_operations logfs_dir_iops = { | |
806 | .create = logfs_create, | |
807 | .link = logfs_link, | |
808 | .lookup = logfs_lookup, | |
809 | .mkdir = logfs_mkdir, | |
810 | .mknod = logfs_mknod, | |
811 | .rename = logfs_rename, | |
812 | .rmdir = logfs_rmdir, | |
813 | .permission = logfs_permission, | |
814 | .symlink = logfs_symlink, | |
815 | .unlink = logfs_unlink, | |
816 | }; | |
817 | const struct file_operations logfs_dir_fops = { | |
818 | .fsync = logfs_fsync, | |
819 | .ioctl = logfs_ioctl, | |
820 | .readdir = logfs_readdir, | |
821 | .read = generic_read_dir, | |
822 | }; |