Commit | Line | Data |
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3241b1d3 JT |
1 | /* |
2 | * Copyright (C) 2011 Red Hat, Inc. | |
3 | * | |
4 | * This file is released under the GPL. | |
5 | */ | |
6 | #include "dm-block-manager.h" | |
7 | #include "dm-persistent-data-internal.h" | |
8 | #include "../dm-bufio.h" | |
9 | ||
10 | #include <linux/crc32c.h> | |
11 | #include <linux/module.h> | |
12 | #include <linux/slab.h> | |
13 | #include <linux/rwsem.h> | |
14 | #include <linux/device-mapper.h> | |
15 | #include <linux/stacktrace.h> | |
16 | ||
17 | #define DM_MSG_PREFIX "block manager" | |
18 | ||
19 | /*----------------------------------------------------------------*/ | |
20 | ||
21 | /* | |
22 | * This is a read/write semaphore with a couple of differences. | |
23 | * | |
24 | * i) There is a restriction on the number of concurrent read locks that | |
25 | * may be held at once. This is just an implementation detail. | |
26 | * | |
27 | * ii) Recursive locking attempts are detected and return EINVAL. A stack | |
83f0d77a | 28 | * trace is also emitted for the previous lock acquisition. |
3241b1d3 JT |
29 | * |
30 | * iii) Priority is given to write locks. | |
31 | */ | |
32 | #define MAX_HOLDERS 4 | |
33 | #define MAX_STACK 10 | |
34 | ||
35 | typedef unsigned long stack_entries[MAX_STACK]; | |
36 | ||
37 | struct block_lock { | |
38 | spinlock_t lock; | |
39 | __s32 count; | |
40 | struct list_head waiters; | |
41 | struct task_struct *holders[MAX_HOLDERS]; | |
42 | ||
43 | #ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING | |
44 | struct stack_trace traces[MAX_HOLDERS]; | |
45 | stack_entries entries[MAX_HOLDERS]; | |
46 | #endif | |
47 | }; | |
48 | ||
49 | struct waiter { | |
50 | struct list_head list; | |
51 | struct task_struct *task; | |
52 | int wants_write; | |
53 | }; | |
54 | ||
55 | static unsigned __find_holder(struct block_lock *lock, | |
56 | struct task_struct *task) | |
57 | { | |
58 | unsigned i; | |
59 | ||
60 | for (i = 0; i < MAX_HOLDERS; i++) | |
61 | if (lock->holders[i] == task) | |
62 | break; | |
63 | ||
64 | BUG_ON(i == MAX_HOLDERS); | |
65 | return i; | |
66 | } | |
67 | ||
68 | /* call this *after* you increment lock->count */ | |
69 | static void __add_holder(struct block_lock *lock, struct task_struct *task) | |
70 | { | |
71 | unsigned h = __find_holder(lock, NULL); | |
72 | #ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING | |
73 | struct stack_trace *t; | |
74 | #endif | |
75 | ||
76 | get_task_struct(task); | |
77 | lock->holders[h] = task; | |
78 | ||
79 | #ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING | |
80 | t = lock->traces + h; | |
81 | t->nr_entries = 0; | |
82 | t->max_entries = MAX_STACK; | |
83 | t->entries = lock->entries[h]; | |
84 | t->skip = 2; | |
85 | save_stack_trace(t); | |
86 | #endif | |
87 | } | |
88 | ||
89 | /* call this *before* you decrement lock->count */ | |
90 | static void __del_holder(struct block_lock *lock, struct task_struct *task) | |
91 | { | |
92 | unsigned h = __find_holder(lock, task); | |
93 | lock->holders[h] = NULL; | |
94 | put_task_struct(task); | |
95 | } | |
96 | ||
97 | static int __check_holder(struct block_lock *lock) | |
98 | { | |
99 | unsigned i; | |
3241b1d3 JT |
100 | |
101 | for (i = 0; i < MAX_HOLDERS; i++) { | |
102 | if (lock->holders[i] == current) { | |
10343180 | 103 | DMERR("recursive lock detected in metadata"); |
3241b1d3 JT |
104 | #ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING |
105 | DMERR("previously held here:"); | |
106 | print_stack_trace(lock->traces + i, 4); | |
107 | ||
83f0d77a | 108 | DMERR("subsequent acquisition attempted here:"); |
313c9b97 | 109 | dump_stack(); |
3241b1d3 JT |
110 | #endif |
111 | return -EINVAL; | |
112 | } | |
113 | } | |
114 | ||
115 | return 0; | |
116 | } | |
117 | ||
118 | static void __wait(struct waiter *w) | |
119 | { | |
120 | for (;;) { | |
121 | set_task_state(current, TASK_UNINTERRUPTIBLE); | |
122 | ||
123 | if (!w->task) | |
124 | break; | |
125 | ||
126 | schedule(); | |
127 | } | |
128 | ||
129 | set_task_state(current, TASK_RUNNING); | |
130 | } | |
131 | ||
132 | static void __wake_waiter(struct waiter *w) | |
133 | { | |
134 | struct task_struct *task; | |
135 | ||
136 | list_del(&w->list); | |
137 | task = w->task; | |
138 | smp_mb(); | |
139 | w->task = NULL; | |
140 | wake_up_process(task); | |
141 | } | |
142 | ||
143 | /* | |
144 | * We either wake a few readers or a single writer. | |
145 | */ | |
146 | static void __wake_many(struct block_lock *lock) | |
147 | { | |
148 | struct waiter *w, *tmp; | |
149 | ||
150 | BUG_ON(lock->count < 0); | |
151 | list_for_each_entry_safe(w, tmp, &lock->waiters, list) { | |
152 | if (lock->count >= MAX_HOLDERS) | |
153 | return; | |
154 | ||
155 | if (w->wants_write) { | |
156 | if (lock->count > 0) | |
157 | return; /* still read locked */ | |
158 | ||
159 | lock->count = -1; | |
160 | __add_holder(lock, w->task); | |
161 | __wake_waiter(w); | |
162 | return; | |
163 | } | |
164 | ||
165 | lock->count++; | |
166 | __add_holder(lock, w->task); | |
167 | __wake_waiter(w); | |
168 | } | |
169 | } | |
170 | ||
171 | static void bl_init(struct block_lock *lock) | |
172 | { | |
173 | int i; | |
174 | ||
175 | spin_lock_init(&lock->lock); | |
176 | lock->count = 0; | |
177 | INIT_LIST_HEAD(&lock->waiters); | |
178 | for (i = 0; i < MAX_HOLDERS; i++) | |
179 | lock->holders[i] = NULL; | |
180 | } | |
181 | ||
182 | static int __available_for_read(struct block_lock *lock) | |
183 | { | |
184 | return lock->count >= 0 && | |
185 | lock->count < MAX_HOLDERS && | |
186 | list_empty(&lock->waiters); | |
187 | } | |
188 | ||
189 | static int bl_down_read(struct block_lock *lock) | |
190 | { | |
191 | int r; | |
192 | struct waiter w; | |
193 | ||
194 | spin_lock(&lock->lock); | |
195 | r = __check_holder(lock); | |
196 | if (r) { | |
197 | spin_unlock(&lock->lock); | |
198 | return r; | |
199 | } | |
200 | ||
201 | if (__available_for_read(lock)) { | |
202 | lock->count++; | |
203 | __add_holder(lock, current); | |
204 | spin_unlock(&lock->lock); | |
205 | return 0; | |
206 | } | |
207 | ||
208 | get_task_struct(current); | |
209 | ||
210 | w.task = current; | |
211 | w.wants_write = 0; | |
212 | list_add_tail(&w.list, &lock->waiters); | |
213 | spin_unlock(&lock->lock); | |
214 | ||
215 | __wait(&w); | |
216 | put_task_struct(current); | |
217 | return 0; | |
218 | } | |
219 | ||
220 | static int bl_down_read_nonblock(struct block_lock *lock) | |
221 | { | |
222 | int r; | |
223 | ||
224 | spin_lock(&lock->lock); | |
225 | r = __check_holder(lock); | |
226 | if (r) | |
227 | goto out; | |
228 | ||
229 | if (__available_for_read(lock)) { | |
230 | lock->count++; | |
231 | __add_holder(lock, current); | |
232 | r = 0; | |
233 | } else | |
234 | r = -EWOULDBLOCK; | |
235 | ||
236 | out: | |
237 | spin_unlock(&lock->lock); | |
238 | return r; | |
239 | } | |
240 | ||
241 | static void bl_up_read(struct block_lock *lock) | |
242 | { | |
243 | spin_lock(&lock->lock); | |
244 | BUG_ON(lock->count <= 0); | |
245 | __del_holder(lock, current); | |
246 | --lock->count; | |
247 | if (!list_empty(&lock->waiters)) | |
248 | __wake_many(lock); | |
249 | spin_unlock(&lock->lock); | |
250 | } | |
251 | ||
252 | static int bl_down_write(struct block_lock *lock) | |
253 | { | |
254 | int r; | |
255 | struct waiter w; | |
256 | ||
257 | spin_lock(&lock->lock); | |
258 | r = __check_holder(lock); | |
259 | if (r) { | |
260 | spin_unlock(&lock->lock); | |
261 | return r; | |
262 | } | |
263 | ||
264 | if (lock->count == 0 && list_empty(&lock->waiters)) { | |
265 | lock->count = -1; | |
266 | __add_holder(lock, current); | |
267 | spin_unlock(&lock->lock); | |
268 | return 0; | |
269 | } | |
270 | ||
271 | get_task_struct(current); | |
272 | w.task = current; | |
273 | w.wants_write = 1; | |
274 | ||
275 | /* | |
276 | * Writers given priority. We know there's only one mutator in the | |
277 | * system, so ignoring the ordering reversal. | |
278 | */ | |
279 | list_add(&w.list, &lock->waiters); | |
280 | spin_unlock(&lock->lock); | |
281 | ||
282 | __wait(&w); | |
283 | put_task_struct(current); | |
284 | ||
285 | return 0; | |
286 | } | |
287 | ||
288 | static void bl_up_write(struct block_lock *lock) | |
289 | { | |
290 | spin_lock(&lock->lock); | |
291 | __del_holder(lock, current); | |
292 | lock->count = 0; | |
293 | if (!list_empty(&lock->waiters)) | |
294 | __wake_many(lock); | |
295 | spin_unlock(&lock->lock); | |
296 | } | |
297 | ||
298 | static void report_recursive_bug(dm_block_t b, int r) | |
299 | { | |
300 | if (r == -EINVAL) | |
301 | DMERR("recursive acquisition of block %llu requested.", | |
302 | (unsigned long long) b); | |
303 | } | |
304 | ||
305 | /*----------------------------------------------------------------*/ | |
306 | ||
307 | /* | |
308 | * Block manager is currently implemented using dm-bufio. struct | |
309 | * dm_block_manager and struct dm_block map directly onto a couple of | |
310 | * structs in the bufio interface. I want to retain the freedom to move | |
311 | * away from bufio in the future. So these structs are just cast within | |
312 | * this .c file, rather than making it through to the public interface. | |
313 | */ | |
314 | static struct dm_buffer *to_buffer(struct dm_block *b) | |
315 | { | |
316 | return (struct dm_buffer *) b; | |
317 | } | |
318 | ||
3241b1d3 JT |
319 | dm_block_t dm_block_location(struct dm_block *b) |
320 | { | |
321 | return dm_bufio_get_block_number(to_buffer(b)); | |
322 | } | |
323 | EXPORT_SYMBOL_GPL(dm_block_location); | |
324 | ||
325 | void *dm_block_data(struct dm_block *b) | |
326 | { | |
327 | return dm_bufio_get_block_data(to_buffer(b)); | |
328 | } | |
329 | EXPORT_SYMBOL_GPL(dm_block_data); | |
330 | ||
331 | struct buffer_aux { | |
332 | struct dm_block_validator *validator; | |
333 | struct block_lock lock; | |
334 | int write_locked; | |
335 | }; | |
336 | ||
337 | static void dm_block_manager_alloc_callback(struct dm_buffer *buf) | |
338 | { | |
339 | struct buffer_aux *aux = dm_bufio_get_aux_data(buf); | |
340 | aux->validator = NULL; | |
341 | bl_init(&aux->lock); | |
342 | } | |
343 | ||
344 | static void dm_block_manager_write_callback(struct dm_buffer *buf) | |
345 | { | |
346 | struct buffer_aux *aux = dm_bufio_get_aux_data(buf); | |
347 | if (aux->validator) { | |
348 | aux->validator->prepare_for_write(aux->validator, (struct dm_block *) buf, | |
349 | dm_bufio_get_block_size(dm_bufio_get_client(buf))); | |
350 | } | |
351 | } | |
352 | ||
353 | /*---------------------------------------------------------------- | |
354 | * Public interface | |
355 | *--------------------------------------------------------------*/ | |
51a0f659 JT |
356 | struct dm_block_manager { |
357 | struct dm_bufio_client *bufio; | |
31097557 | 358 | bool read_only:1; |
51a0f659 JT |
359 | }; |
360 | ||
3241b1d3 JT |
361 | struct dm_block_manager *dm_block_manager_create(struct block_device *bdev, |
362 | unsigned block_size, | |
363 | unsigned cache_size, | |
364 | unsigned max_held_per_thread) | |
365 | { | |
51a0f659 JT |
366 | int r; |
367 | struct dm_block_manager *bm; | |
368 | ||
369 | bm = kmalloc(sizeof(*bm), GFP_KERNEL); | |
370 | if (!bm) { | |
371 | r = -ENOMEM; | |
372 | goto bad; | |
373 | } | |
374 | ||
375 | bm->bufio = dm_bufio_client_create(bdev, block_size, max_held_per_thread, | |
376 | sizeof(struct buffer_aux), | |
377 | dm_block_manager_alloc_callback, | |
378 | dm_block_manager_write_callback); | |
379 | if (IS_ERR(bm->bufio)) { | |
380 | r = PTR_ERR(bm->bufio); | |
381 | kfree(bm); | |
382 | goto bad; | |
383 | } | |
384 | ||
31097557 JT |
385 | bm->read_only = false; |
386 | ||
51a0f659 JT |
387 | return bm; |
388 | ||
389 | bad: | |
390 | return ERR_PTR(r); | |
3241b1d3 JT |
391 | } |
392 | EXPORT_SYMBOL_GPL(dm_block_manager_create); | |
393 | ||
394 | void dm_block_manager_destroy(struct dm_block_manager *bm) | |
395 | { | |
51a0f659 JT |
396 | dm_bufio_client_destroy(bm->bufio); |
397 | kfree(bm); | |
3241b1d3 JT |
398 | } |
399 | EXPORT_SYMBOL_GPL(dm_block_manager_destroy); | |
400 | ||
401 | unsigned dm_bm_block_size(struct dm_block_manager *bm) | |
402 | { | |
51a0f659 | 403 | return dm_bufio_get_block_size(bm->bufio); |
3241b1d3 JT |
404 | } |
405 | EXPORT_SYMBOL_GPL(dm_bm_block_size); | |
406 | ||
407 | dm_block_t dm_bm_nr_blocks(struct dm_block_manager *bm) | |
408 | { | |
51a0f659 | 409 | return dm_bufio_get_device_size(bm->bufio); |
3241b1d3 JT |
410 | } |
411 | ||
412 | static int dm_bm_validate_buffer(struct dm_block_manager *bm, | |
413 | struct dm_buffer *buf, | |
414 | struct buffer_aux *aux, | |
415 | struct dm_block_validator *v) | |
416 | { | |
417 | if (unlikely(!aux->validator)) { | |
418 | int r; | |
419 | if (!v) | |
420 | return 0; | |
51a0f659 | 421 | r = v->check(v, (struct dm_block *) buf, dm_bufio_get_block_size(bm->bufio)); |
a5bd968a | 422 | if (unlikely(r)) { |
89ddeb8c MS |
423 | DMERR_LIMIT("%s validator check failed for block %llu", v->name, |
424 | (unsigned long long) dm_bufio_get_block_number(buf)); | |
3241b1d3 | 425 | return r; |
a5bd968a | 426 | } |
3241b1d3 JT |
427 | aux->validator = v; |
428 | } else { | |
429 | if (unlikely(aux->validator != v)) { | |
89ddeb8c MS |
430 | DMERR_LIMIT("validator mismatch (old=%s vs new=%s) for block %llu", |
431 | aux->validator->name, v ? v->name : "NULL", | |
432 | (unsigned long long) dm_bufio_get_block_number(buf)); | |
3241b1d3 JT |
433 | return -EINVAL; |
434 | } | |
435 | } | |
436 | ||
437 | return 0; | |
438 | } | |
439 | int dm_bm_read_lock(struct dm_block_manager *bm, dm_block_t b, | |
440 | struct dm_block_validator *v, | |
441 | struct dm_block **result) | |
442 | { | |
443 | struct buffer_aux *aux; | |
444 | void *p; | |
445 | int r; | |
446 | ||
51a0f659 | 447 | p = dm_bufio_read(bm->bufio, b, (struct dm_buffer **) result); |
fc0a4461 | 448 | if (IS_ERR(p)) |
3241b1d3 JT |
449 | return PTR_ERR(p); |
450 | ||
451 | aux = dm_bufio_get_aux_data(to_buffer(*result)); | |
452 | r = bl_down_read(&aux->lock); | |
453 | if (unlikely(r)) { | |
454 | dm_bufio_release(to_buffer(*result)); | |
455 | report_recursive_bug(b, r); | |
456 | return r; | |
457 | } | |
458 | ||
459 | aux->write_locked = 0; | |
460 | ||
461 | r = dm_bm_validate_buffer(bm, to_buffer(*result), aux, v); | |
462 | if (unlikely(r)) { | |
463 | bl_up_read(&aux->lock); | |
464 | dm_bufio_release(to_buffer(*result)); | |
465 | return r; | |
466 | } | |
467 | ||
468 | return 0; | |
469 | } | |
470 | EXPORT_SYMBOL_GPL(dm_bm_read_lock); | |
471 | ||
472 | int dm_bm_write_lock(struct dm_block_manager *bm, | |
473 | dm_block_t b, struct dm_block_validator *v, | |
474 | struct dm_block **result) | |
475 | { | |
476 | struct buffer_aux *aux; | |
477 | void *p; | |
478 | int r; | |
479 | ||
31097557 JT |
480 | if (bm->read_only) |
481 | return -EPERM; | |
482 | ||
51a0f659 | 483 | p = dm_bufio_read(bm->bufio, b, (struct dm_buffer **) result); |
fc0a4461 | 484 | if (IS_ERR(p)) |
3241b1d3 JT |
485 | return PTR_ERR(p); |
486 | ||
487 | aux = dm_bufio_get_aux_data(to_buffer(*result)); | |
488 | r = bl_down_write(&aux->lock); | |
489 | if (r) { | |
490 | dm_bufio_release(to_buffer(*result)); | |
491 | report_recursive_bug(b, r); | |
492 | return r; | |
493 | } | |
494 | ||
495 | aux->write_locked = 1; | |
496 | ||
497 | r = dm_bm_validate_buffer(bm, to_buffer(*result), aux, v); | |
498 | if (unlikely(r)) { | |
499 | bl_up_write(&aux->lock); | |
500 | dm_bufio_release(to_buffer(*result)); | |
501 | return r; | |
502 | } | |
503 | ||
504 | return 0; | |
505 | } | |
506 | EXPORT_SYMBOL_GPL(dm_bm_write_lock); | |
507 | ||
508 | int dm_bm_read_try_lock(struct dm_block_manager *bm, | |
509 | dm_block_t b, struct dm_block_validator *v, | |
510 | struct dm_block **result) | |
511 | { | |
512 | struct buffer_aux *aux; | |
513 | void *p; | |
514 | int r; | |
515 | ||
51a0f659 | 516 | p = dm_bufio_get(bm->bufio, b, (struct dm_buffer **) result); |
fc0a4461 | 517 | if (IS_ERR(p)) |
3241b1d3 JT |
518 | return PTR_ERR(p); |
519 | if (unlikely(!p)) | |
520 | return -EWOULDBLOCK; | |
521 | ||
522 | aux = dm_bufio_get_aux_data(to_buffer(*result)); | |
523 | r = bl_down_read_nonblock(&aux->lock); | |
524 | if (r < 0) { | |
525 | dm_bufio_release(to_buffer(*result)); | |
526 | report_recursive_bug(b, r); | |
527 | return r; | |
528 | } | |
529 | aux->write_locked = 0; | |
530 | ||
531 | r = dm_bm_validate_buffer(bm, to_buffer(*result), aux, v); | |
532 | if (unlikely(r)) { | |
533 | bl_up_read(&aux->lock); | |
534 | dm_bufio_release(to_buffer(*result)); | |
535 | return r; | |
536 | } | |
537 | ||
538 | return 0; | |
539 | } | |
540 | ||
541 | int dm_bm_write_lock_zero(struct dm_block_manager *bm, | |
542 | dm_block_t b, struct dm_block_validator *v, | |
543 | struct dm_block **result) | |
544 | { | |
545 | int r; | |
546 | struct buffer_aux *aux; | |
547 | void *p; | |
548 | ||
31097557 JT |
549 | if (bm->read_only) |
550 | return -EPERM; | |
551 | ||
51a0f659 | 552 | p = dm_bufio_new(bm->bufio, b, (struct dm_buffer **) result); |
fc0a4461 | 553 | if (IS_ERR(p)) |
3241b1d3 JT |
554 | return PTR_ERR(p); |
555 | ||
556 | memset(p, 0, dm_bm_block_size(bm)); | |
557 | ||
558 | aux = dm_bufio_get_aux_data(to_buffer(*result)); | |
559 | r = bl_down_write(&aux->lock); | |
560 | if (r) { | |
561 | dm_bufio_release(to_buffer(*result)); | |
562 | return r; | |
563 | } | |
564 | ||
565 | aux->write_locked = 1; | |
566 | aux->validator = v; | |
567 | ||
568 | return 0; | |
569 | } | |
384ef0e6 | 570 | EXPORT_SYMBOL_GPL(dm_bm_write_lock_zero); |
3241b1d3 | 571 | |
4c7da06f | 572 | void dm_bm_unlock(struct dm_block *b) |
3241b1d3 JT |
573 | { |
574 | struct buffer_aux *aux; | |
575 | aux = dm_bufio_get_aux_data(to_buffer(b)); | |
576 | ||
577 | if (aux->write_locked) { | |
578 | dm_bufio_mark_buffer_dirty(to_buffer(b)); | |
579 | bl_up_write(&aux->lock); | |
580 | } else | |
581 | bl_up_read(&aux->lock); | |
582 | ||
583 | dm_bufio_release(to_buffer(b)); | |
3241b1d3 JT |
584 | } |
585 | EXPORT_SYMBOL_GPL(dm_bm_unlock); | |
586 | ||
a9d45396 | 587 | int dm_bm_flush(struct dm_block_manager *bm) |
3241b1d3 | 588 | { |
31097557 JT |
589 | if (bm->read_only) |
590 | return -EPERM; | |
591 | ||
51a0f659 | 592 | return dm_bufio_write_dirty_buffers(bm->bufio); |
3241b1d3 | 593 | } |
a9d45396 | 594 | EXPORT_SYMBOL_GPL(dm_bm_flush); |
3241b1d3 | 595 | |
04f17c80 JT |
596 | void dm_bm_prefetch(struct dm_block_manager *bm, dm_block_t b) |
597 | { | |
598 | dm_bufio_prefetch(bm->bufio, b, 1); | |
599 | } | |
600 | ||
49f154c7 MS |
601 | bool dm_bm_is_read_only(struct dm_block_manager *bm) |
602 | { | |
603 | return bm->read_only; | |
604 | } | |
605 | EXPORT_SYMBOL_GPL(dm_bm_is_read_only); | |
606 | ||
31097557 JT |
607 | void dm_bm_set_read_only(struct dm_block_manager *bm) |
608 | { | |
609 | bm->read_only = true; | |
610 | } | |
611 | EXPORT_SYMBOL_GPL(dm_bm_set_read_only); | |
612 | ||
9b7aaa64 JT |
613 | void dm_bm_set_read_write(struct dm_block_manager *bm) |
614 | { | |
615 | bm->read_only = false; | |
616 | } | |
617 | EXPORT_SYMBOL_GPL(dm_bm_set_read_write); | |
618 | ||
3241b1d3 JT |
619 | u32 dm_bm_checksum(const void *data, size_t len, u32 init_xor) |
620 | { | |
621 | return crc32c(~(u32) 0, data, len) ^ init_xor; | |
622 | } | |
623 | EXPORT_SYMBOL_GPL(dm_bm_checksum); | |
624 | ||
625 | /*----------------------------------------------------------------*/ | |
626 | ||
627 | MODULE_LICENSE("GPL"); | |
628 | MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>"); | |
629 | MODULE_DESCRIPTION("Immutable metadata library for dm"); | |
630 | ||
631 | /*----------------------------------------------------------------*/ |