1 /*
2  * Copyright (C) 2011 Red Hat, Inc.
3  *
4  * This file is released under the GPL.
5  */
6 
7 #include "dm-space-map.h"
8 #include "dm-space-map-common.h"
9 #include "dm-space-map-metadata.h"
10 
11 #include <linux/list.h>
12 #include <linux/slab.h>
13 #include <linux/device-mapper.h>
14 #include <linux/kernel.h>
15 
16 #define DM_MSG_PREFIX "space map metadata"
17 
18 /*----------------------------------------------------------------*/
19 
20 /*
21  * An edge triggered threshold.
22  */
23 struct threshold {
24 	bool threshold_set;
25 	bool value_set;
26 	dm_block_t threshold;
27 	dm_block_t current_value;
28 	dm_sm_threshold_fn fn;
29 	void *context;
30 };
31 
threshold_init(struct threshold * t)32 static void threshold_init(struct threshold *t)
33 {
34 	t->threshold_set = false;
35 	t->value_set = false;
36 }
37 
set_threshold(struct threshold * t,dm_block_t value,dm_sm_threshold_fn fn,void * context)38 static void set_threshold(struct threshold *t, dm_block_t value,
39 			  dm_sm_threshold_fn fn, void *context)
40 {
41 	t->threshold_set = true;
42 	t->threshold = value;
43 	t->fn = fn;
44 	t->context = context;
45 }
46 
below_threshold(struct threshold * t,dm_block_t value)47 static bool below_threshold(struct threshold *t, dm_block_t value)
48 {
49 	return t->threshold_set && value <= t->threshold;
50 }
51 
threshold_already_triggered(struct threshold * t)52 static bool threshold_already_triggered(struct threshold *t)
53 {
54 	return t->value_set && below_threshold(t, t->current_value);
55 }
56 
check_threshold(struct threshold * t,dm_block_t value)57 static void check_threshold(struct threshold *t, dm_block_t value)
58 {
59 	if (below_threshold(t, value) &&
60 	    !threshold_already_triggered(t))
61 		t->fn(t->context);
62 
63 	t->value_set = true;
64 	t->current_value = value;
65 }
66 
67 /*----------------------------------------------------------------*/
68 
69 /*
70  * Space map interface.
71  *
72  * The low level disk format is written using the standard btree and
73  * transaction manager.  This means that performing disk operations may
74  * cause us to recurse into the space map in order to allocate new blocks.
75  * For this reason we have a pool of pre-allocated blocks large enough to
76  * service any metadata_ll_disk operation.
77  */
78 
79 /*
80  * FIXME: we should calculate this based on the size of the device.
81  * Only the metadata space map needs this functionality.
82  */
83 #define MAX_RECURSIVE_ALLOCATIONS 1024
84 
85 enum block_op_type {
86 	BOP_INC,
87 	BOP_DEC
88 };
89 
90 struct block_op {
91 	enum block_op_type type;
92 	dm_block_t b;
93 	dm_block_t e;
94 };
95 
96 struct bop_ring_buffer {
97 	unsigned begin;
98 	unsigned end;
99 	struct block_op bops[MAX_RECURSIVE_ALLOCATIONS + 1];
100 };
101 
brb_init(struct bop_ring_buffer * brb)102 static void brb_init(struct bop_ring_buffer *brb)
103 {
104 	brb->begin = 0;
105 	brb->end = 0;
106 }
107 
brb_empty(struct bop_ring_buffer * brb)108 static bool brb_empty(struct bop_ring_buffer *brb)
109 {
110 	return brb->begin == brb->end;
111 }
112 
brb_next(struct bop_ring_buffer * brb,unsigned old)113 static unsigned brb_next(struct bop_ring_buffer *brb, unsigned old)
114 {
115 	unsigned r = old + 1;
116 	return r >= ARRAY_SIZE(brb->bops) ? 0 : r;
117 }
118 
brb_push(struct bop_ring_buffer * brb,enum block_op_type type,dm_block_t b,dm_block_t e)119 static int brb_push(struct bop_ring_buffer *brb,
120 		    enum block_op_type type, dm_block_t b, dm_block_t e)
121 {
122 	struct block_op *bop;
123 	unsigned next = brb_next(brb, brb->end);
124 
125 	/*
126 	 * We don't allow the last bop to be filled, this way we can
127 	 * differentiate between full and empty.
128 	 */
129 	if (next == brb->begin)
130 		return -ENOMEM;
131 
132 	bop = brb->bops + brb->end;
133 	bop->type = type;
134 	bop->b = b;
135 	bop->e = e;
136 
137 	brb->end = next;
138 
139 	return 0;
140 }
141 
brb_peek(struct bop_ring_buffer * brb,struct block_op * result)142 static int brb_peek(struct bop_ring_buffer *brb, struct block_op *result)
143 {
144 	struct block_op *bop;
145 
146 	if (brb_empty(brb))
147 		return -ENODATA;
148 
149 	bop = brb->bops + brb->begin;
150 	memcpy(result, bop, sizeof(*result));
151 	return 0;
152 }
153 
brb_pop(struct bop_ring_buffer * brb)154 static int brb_pop(struct bop_ring_buffer *brb)
155 {
156 	if (brb_empty(brb))
157 		return -ENODATA;
158 
159 	brb->begin = brb_next(brb, brb->begin);
160 
161 	return 0;
162 }
163 
164 /*----------------------------------------------------------------*/
165 
166 struct sm_metadata {
167 	struct dm_space_map sm;
168 
169 	struct ll_disk ll;
170 	struct ll_disk old_ll;
171 
172 	dm_block_t begin;
173 
174 	unsigned recursion_count;
175 	unsigned allocated_this_transaction;
176 	struct bop_ring_buffer uncommitted;
177 
178 	struct threshold threshold;
179 };
180 
add_bop(struct sm_metadata * smm,enum block_op_type type,dm_block_t b,dm_block_t e)181 static int add_bop(struct sm_metadata *smm, enum block_op_type type, dm_block_t b, dm_block_t e)
182 {
183 	int r = brb_push(&smm->uncommitted, type, b, e);
184 	if (r) {
185 		DMERR("too many recursive allocations");
186 		return -ENOMEM;
187 	}
188 
189 	return 0;
190 }
191 
commit_bop(struct sm_metadata * smm,struct block_op * op)192 static int commit_bop(struct sm_metadata *smm, struct block_op *op)
193 {
194 	int r = 0;
195 	int32_t nr_allocations;
196 
197 	switch (op->type) {
198 	case BOP_INC:
199 		r = sm_ll_inc(&smm->ll, op->b, op->e, &nr_allocations);
200 		break;
201 
202 	case BOP_DEC:
203 		r = sm_ll_dec(&smm->ll, op->b, op->e, &nr_allocations);
204 		break;
205 	}
206 
207 	return r;
208 }
209 
in(struct sm_metadata * smm)210 static void in(struct sm_metadata *smm)
211 {
212 	smm->recursion_count++;
213 }
214 
apply_bops(struct sm_metadata * smm)215 static int apply_bops(struct sm_metadata *smm)
216 {
217 	int r = 0;
218 
219 	while (!brb_empty(&smm->uncommitted)) {
220 		struct block_op bop;
221 
222 		r = brb_peek(&smm->uncommitted, &bop);
223 		if (r) {
224 			DMERR("bug in bop ring buffer");
225 			break;
226 		}
227 
228 		r = commit_bop(smm, &bop);
229 		if (r)
230 			break;
231 
232 		brb_pop(&smm->uncommitted);
233 	}
234 
235 	return r;
236 }
237 
out(struct sm_metadata * smm)238 static int out(struct sm_metadata *smm)
239 {
240 	int r = 0;
241 
242 	/*
243 	 * If we're not recursing then very bad things are happening.
244 	 */
245 	if (!smm->recursion_count) {
246 		DMERR("lost track of recursion depth");
247 		return -ENOMEM;
248 	}
249 
250 	if (smm->recursion_count == 1)
251 		r = apply_bops(smm);
252 
253 	smm->recursion_count--;
254 
255 	return r;
256 }
257 
258 /*
259  * When using the out() function above, we often want to combine an error
260  * code for the operation run in the recursive context with that from
261  * out().
262  */
combine_errors(int r1,int r2)263 static int combine_errors(int r1, int r2)
264 {
265 	return r1 ? r1 : r2;
266 }
267 
recursing(struct sm_metadata * smm)268 static int recursing(struct sm_metadata *smm)
269 {
270 	return smm->recursion_count;
271 }
272 
sm_metadata_destroy(struct dm_space_map * sm)273 static void sm_metadata_destroy(struct dm_space_map *sm)
274 {
275 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
276 
277 	kfree(smm);
278 }
279 
sm_metadata_get_nr_blocks(struct dm_space_map * sm,dm_block_t * count)280 static int sm_metadata_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
281 {
282 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
283 
284 	*count = smm->ll.nr_blocks;
285 
286 	return 0;
287 }
288 
sm_metadata_get_nr_free(struct dm_space_map * sm,dm_block_t * count)289 static int sm_metadata_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
290 {
291 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
292 
293 	*count = smm->old_ll.nr_blocks - smm->old_ll.nr_allocated -
294 		 smm->allocated_this_transaction;
295 
296 	return 0;
297 }
298 
sm_metadata_get_count(struct dm_space_map * sm,dm_block_t b,uint32_t * result)299 static int sm_metadata_get_count(struct dm_space_map *sm, dm_block_t b,
300 				 uint32_t *result)
301 {
302 	int r;
303 	unsigned i;
304 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
305 	unsigned adjustment = 0;
306 
307 	/*
308 	 * We may have some uncommitted adjustments to add.  This list
309 	 * should always be really short.
310 	 */
311 	for (i = smm->uncommitted.begin;
312 	     i != smm->uncommitted.end;
313 	     i = brb_next(&smm->uncommitted, i)) {
314 		struct block_op *op = smm->uncommitted.bops + i;
315 
316 		if (b < op->b || b >= op->e)
317 			continue;
318 
319 		switch (op->type) {
320 		case BOP_INC:
321 			adjustment++;
322 			break;
323 
324 		case BOP_DEC:
325 			adjustment--;
326 			break;
327 		}
328 	}
329 
330 	r = sm_ll_lookup(&smm->ll, b, result);
331 	if (r)
332 		return r;
333 
334 	*result += adjustment;
335 
336 	return 0;
337 }
338 
sm_metadata_count_is_more_than_one(struct dm_space_map * sm,dm_block_t b,int * result)339 static int sm_metadata_count_is_more_than_one(struct dm_space_map *sm,
340 					      dm_block_t b, int *result)
341 {
342 	int r, adjustment = 0;
343 	unsigned i;
344 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
345 	uint32_t rc;
346 
347 	/*
348 	 * We may have some uncommitted adjustments to add.  This list
349 	 * should always be really short.
350 	 */
351 	for (i = smm->uncommitted.begin;
352 	     i != smm->uncommitted.end;
353 	     i = brb_next(&smm->uncommitted, i)) {
354 
355 		struct block_op *op = smm->uncommitted.bops + i;
356 
357 		if (b < op->b || b >= op->e)
358 			continue;
359 
360 		switch (op->type) {
361 		case BOP_INC:
362 			adjustment++;
363 			break;
364 
365 		case BOP_DEC:
366 			adjustment--;
367 			break;
368 		}
369 	}
370 
371 	if (adjustment > 1) {
372 		*result = 1;
373 		return 0;
374 	}
375 
376 	r = sm_ll_lookup_bitmap(&smm->ll, b, &rc);
377 	if (r)
378 		return r;
379 
380 	if (rc == 3)
381 		/*
382 		 * We err on the side of caution, and always return true.
383 		 */
384 		*result = 1;
385 	else
386 		*result = rc + adjustment > 1;
387 
388 	return 0;
389 }
390 
sm_metadata_set_count(struct dm_space_map * sm,dm_block_t b,uint32_t count)391 static int sm_metadata_set_count(struct dm_space_map *sm, dm_block_t b,
392 				 uint32_t count)
393 {
394 	int r, r2;
395 	int32_t nr_allocations;
396 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
397 
398 	if (smm->recursion_count) {
399 		DMERR("cannot recurse set_count()");
400 		return -EINVAL;
401 	}
402 
403 	in(smm);
404 	r = sm_ll_insert(&smm->ll, b, count, &nr_allocations);
405 	r2 = out(smm);
406 
407 	return combine_errors(r, r2);
408 }
409 
sm_metadata_inc_blocks(struct dm_space_map * sm,dm_block_t b,dm_block_t e)410 static int sm_metadata_inc_blocks(struct dm_space_map *sm, dm_block_t b, dm_block_t e)
411 {
412 	int r, r2 = 0;
413 	int32_t nr_allocations;
414 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
415 
416 	if (recursing(smm)) {
417 		r = add_bop(smm, BOP_INC, b, e);
418 		if (r)
419 			return r;
420 	} else {
421 		in(smm);
422 		r = sm_ll_inc(&smm->ll, b, e, &nr_allocations);
423 		r2 = out(smm);
424 	}
425 
426 	return combine_errors(r, r2);
427 }
428 
sm_metadata_dec_blocks(struct dm_space_map * sm,dm_block_t b,dm_block_t e)429 static int sm_metadata_dec_blocks(struct dm_space_map *sm, dm_block_t b, dm_block_t e)
430 {
431 	int r, r2 = 0;
432 	int32_t nr_allocations;
433 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
434 
435 	if (recursing(smm))
436 		r = add_bop(smm, BOP_DEC, b, e);
437 	else {
438 		in(smm);
439 		r = sm_ll_dec(&smm->ll, b, e, &nr_allocations);
440 		r2 = out(smm);
441 	}
442 
443 	return combine_errors(r, r2);
444 }
445 
sm_metadata_new_block_(struct dm_space_map * sm,dm_block_t * b)446 static int sm_metadata_new_block_(struct dm_space_map *sm, dm_block_t *b)
447 {
448 	int r, r2 = 0;
449 	int32_t nr_allocations;
450 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
451 
452 	/*
453 	 * Any block we allocate has to be free in both the old and current ll.
454 	 */
455 	r = sm_ll_find_common_free_block(&smm->old_ll, &smm->ll, smm->begin, smm->ll.nr_blocks, b);
456 	if (r == -ENOSPC) {
457 		/*
458 		 * There's no free block between smm->begin and the end of the metadata device.
459 		 * We search before smm->begin in case something has been freed.
460 		 */
461 		r = sm_ll_find_common_free_block(&smm->old_ll, &smm->ll, 0, smm->begin, b);
462 	}
463 
464 	if (r)
465 		return r;
466 
467 	smm->begin = *b + 1;
468 
469 	if (recursing(smm))
470 		r = add_bop(smm, BOP_INC, *b, *b + 1);
471 	else {
472 		in(smm);
473 		r = sm_ll_inc(&smm->ll, *b, *b + 1, &nr_allocations);
474 		r2 = out(smm);
475 	}
476 
477 	if (!r)
478 		smm->allocated_this_transaction++;
479 
480 	return combine_errors(r, r2);
481 }
482 
sm_metadata_new_block(struct dm_space_map * sm,dm_block_t * b)483 static int sm_metadata_new_block(struct dm_space_map *sm, dm_block_t *b)
484 {
485 	dm_block_t count;
486 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
487 
488 	int r = sm_metadata_new_block_(sm, b);
489 	if (r) {
490 		DMERR_LIMIT("unable to allocate new metadata block");
491 		return r;
492 	}
493 
494 	r = sm_metadata_get_nr_free(sm, &count);
495 	if (r) {
496 		DMERR_LIMIT("couldn't get free block count");
497 		return r;
498 	}
499 
500 	check_threshold(&smm->threshold, count);
501 
502 	return r;
503 }
504 
sm_metadata_commit(struct dm_space_map * sm)505 static int sm_metadata_commit(struct dm_space_map *sm)
506 {
507 	int r;
508 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
509 
510 	r = sm_ll_commit(&smm->ll);
511 	if (r)
512 		return r;
513 
514 	memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll));
515 	smm->allocated_this_transaction = 0;
516 
517 	return 0;
518 }
519 
sm_metadata_register_threshold_callback(struct dm_space_map * sm,dm_block_t threshold,dm_sm_threshold_fn fn,void * context)520 static int sm_metadata_register_threshold_callback(struct dm_space_map *sm,
521 						   dm_block_t threshold,
522 						   dm_sm_threshold_fn fn,
523 						   void *context)
524 {
525 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
526 
527 	set_threshold(&smm->threshold, threshold, fn, context);
528 
529 	return 0;
530 }
531 
sm_metadata_root_size(struct dm_space_map * sm,size_t * result)532 static int sm_metadata_root_size(struct dm_space_map *sm, size_t *result)
533 {
534 	*result = sizeof(struct disk_sm_root);
535 
536 	return 0;
537 }
538 
sm_metadata_copy_root(struct dm_space_map * sm,void * where_le,size_t max)539 static int sm_metadata_copy_root(struct dm_space_map *sm, void *where_le, size_t max)
540 {
541 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
542 	struct disk_sm_root root_le;
543 
544 	root_le.nr_blocks = cpu_to_le64(smm->ll.nr_blocks);
545 	root_le.nr_allocated = cpu_to_le64(smm->ll.nr_allocated);
546 	root_le.bitmap_root = cpu_to_le64(smm->ll.bitmap_root);
547 	root_le.ref_count_root = cpu_to_le64(smm->ll.ref_count_root);
548 
549 	if (max < sizeof(root_le))
550 		return -ENOSPC;
551 
552 	memcpy(where_le, &root_le, sizeof(root_le));
553 
554 	return 0;
555 }
556 
557 static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks);
558 
559 static const struct dm_space_map ops = {
560 	.destroy = sm_metadata_destroy,
561 	.extend = sm_metadata_extend,
562 	.get_nr_blocks = sm_metadata_get_nr_blocks,
563 	.get_nr_free = sm_metadata_get_nr_free,
564 	.get_count = sm_metadata_get_count,
565 	.count_is_more_than_one = sm_metadata_count_is_more_than_one,
566 	.set_count = sm_metadata_set_count,
567 	.inc_blocks = sm_metadata_inc_blocks,
568 	.dec_blocks = sm_metadata_dec_blocks,
569 	.new_block = sm_metadata_new_block,
570 	.commit = sm_metadata_commit,
571 	.root_size = sm_metadata_root_size,
572 	.copy_root = sm_metadata_copy_root,
573 	.register_threshold_callback = sm_metadata_register_threshold_callback
574 };
575 
576 /*----------------------------------------------------------------*/
577 
578 /*
579  * When a new space map is created that manages its own space.  We use
580  * this tiny bootstrap allocator.
581  */
sm_bootstrap_destroy(struct dm_space_map * sm)582 static void sm_bootstrap_destroy(struct dm_space_map *sm)
583 {
584 }
585 
sm_bootstrap_extend(struct dm_space_map * sm,dm_block_t extra_blocks)586 static int sm_bootstrap_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
587 {
588 	DMERR("bootstrap doesn't support extend");
589 
590 	return -EINVAL;
591 }
592 
sm_bootstrap_get_nr_blocks(struct dm_space_map * sm,dm_block_t * count)593 static int sm_bootstrap_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
594 {
595 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
596 
597 	*count = smm->ll.nr_blocks;
598 
599 	return 0;
600 }
601 
sm_bootstrap_get_nr_free(struct dm_space_map * sm,dm_block_t * count)602 static int sm_bootstrap_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
603 {
604 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
605 
606 	*count = smm->ll.nr_blocks - smm->begin;
607 
608 	return 0;
609 }
610 
sm_bootstrap_get_count(struct dm_space_map * sm,dm_block_t b,uint32_t * result)611 static int sm_bootstrap_get_count(struct dm_space_map *sm, dm_block_t b,
612 				  uint32_t *result)
613 {
614 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
615 
616 	*result = (b < smm->begin) ? 1 : 0;
617 
618 	return 0;
619 }
620 
sm_bootstrap_count_is_more_than_one(struct dm_space_map * sm,dm_block_t b,int * result)621 static int sm_bootstrap_count_is_more_than_one(struct dm_space_map *sm,
622 					       dm_block_t b, int *result)
623 {
624 	*result = 0;
625 
626 	return 0;
627 }
628 
sm_bootstrap_set_count(struct dm_space_map * sm,dm_block_t b,uint32_t count)629 static int sm_bootstrap_set_count(struct dm_space_map *sm, dm_block_t b,
630 				  uint32_t count)
631 {
632 	DMERR("bootstrap doesn't support set_count");
633 
634 	return -EINVAL;
635 }
636 
sm_bootstrap_new_block(struct dm_space_map * sm,dm_block_t * b)637 static int sm_bootstrap_new_block(struct dm_space_map *sm, dm_block_t *b)
638 {
639 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
640 
641 	/*
642 	 * We know the entire device is unused.
643 	 */
644 	if (smm->begin == smm->ll.nr_blocks)
645 		return -ENOSPC;
646 
647 	*b = smm->begin++;
648 
649 	return 0;
650 }
651 
sm_bootstrap_inc_blocks(struct dm_space_map * sm,dm_block_t b,dm_block_t e)652 static int sm_bootstrap_inc_blocks(struct dm_space_map *sm, dm_block_t b, dm_block_t e)
653 {
654 	int r;
655 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
656 
657 	r = add_bop(smm, BOP_INC, b, e);
658 	if (r)
659 		return r;
660 
661 	return 0;
662 }
663 
sm_bootstrap_dec_blocks(struct dm_space_map * sm,dm_block_t b,dm_block_t e)664 static int sm_bootstrap_dec_blocks(struct dm_space_map *sm, dm_block_t b, dm_block_t e)
665 {
666 	int r;
667 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
668 
669 	r = add_bop(smm, BOP_DEC, b, e);
670 	if (r)
671 		return r;
672 
673 	return 0;
674 }
675 
sm_bootstrap_commit(struct dm_space_map * sm)676 static int sm_bootstrap_commit(struct dm_space_map *sm)
677 {
678 	return 0;
679 }
680 
sm_bootstrap_root_size(struct dm_space_map * sm,size_t * result)681 static int sm_bootstrap_root_size(struct dm_space_map *sm, size_t *result)
682 {
683 	DMERR("bootstrap doesn't support root_size");
684 
685 	return -EINVAL;
686 }
687 
sm_bootstrap_copy_root(struct dm_space_map * sm,void * where,size_t max)688 static int sm_bootstrap_copy_root(struct dm_space_map *sm, void *where,
689 				  size_t max)
690 {
691 	DMERR("bootstrap doesn't support copy_root");
692 
693 	return -EINVAL;
694 }
695 
696 static const struct dm_space_map bootstrap_ops = {
697 	.destroy = sm_bootstrap_destroy,
698 	.extend = sm_bootstrap_extend,
699 	.get_nr_blocks = sm_bootstrap_get_nr_blocks,
700 	.get_nr_free = sm_bootstrap_get_nr_free,
701 	.get_count = sm_bootstrap_get_count,
702 	.count_is_more_than_one = sm_bootstrap_count_is_more_than_one,
703 	.set_count = sm_bootstrap_set_count,
704 	.inc_blocks = sm_bootstrap_inc_blocks,
705 	.dec_blocks = sm_bootstrap_dec_blocks,
706 	.new_block = sm_bootstrap_new_block,
707 	.commit = sm_bootstrap_commit,
708 	.root_size = sm_bootstrap_root_size,
709 	.copy_root = sm_bootstrap_copy_root,
710 	.register_threshold_callback = NULL
711 };
712 
713 /*----------------------------------------------------------------*/
714 
sm_metadata_extend(struct dm_space_map * sm,dm_block_t extra_blocks)715 static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
716 {
717 	int r;
718 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
719 	dm_block_t old_len = smm->ll.nr_blocks;
720 
721 	/*
722 	 * Flick into a mode where all blocks get allocated in the new area.
723 	 */
724 	smm->begin = old_len;
725 	memcpy(sm, &bootstrap_ops, sizeof(*sm));
726 
727 	/*
728 	 * Extend.
729 	 */
730 	r = sm_ll_extend(&smm->ll, extra_blocks);
731 	if (r)
732 		goto out;
733 
734 	/*
735 	 * We repeatedly increment then commit until the commit doesn't
736 	 * allocate any new blocks.
737 	 */
738 	do {
739 		r = add_bop(smm, BOP_INC, old_len, smm->begin);
740 		if (r)
741 			goto out;
742 
743 		old_len = smm->begin;
744 
745 		r = apply_bops(smm);
746 		if (r) {
747 			DMERR("%s: apply_bops failed", __func__);
748 			goto out;
749 		}
750 
751 		r = sm_ll_commit(&smm->ll);
752 		if (r)
753 			goto out;
754 
755 	} while (old_len != smm->begin);
756 
757 out:
758 	/*
759 	 * Switch back to normal behaviour.
760 	 */
761 	memcpy(sm, &ops, sizeof(*sm));
762 	return r;
763 }
764 
765 /*----------------------------------------------------------------*/
766 
dm_sm_metadata_init(void)767 struct dm_space_map *dm_sm_metadata_init(void)
768 {
769 	struct sm_metadata *smm;
770 
771 	smm = kmalloc(sizeof(*smm), GFP_KERNEL);
772 	if (!smm)
773 		return ERR_PTR(-ENOMEM);
774 
775 	memcpy(&smm->sm, &ops, sizeof(smm->sm));
776 
777 	return &smm->sm;
778 }
779 
dm_sm_metadata_create(struct dm_space_map * sm,struct dm_transaction_manager * tm,dm_block_t nr_blocks,dm_block_t superblock)780 int dm_sm_metadata_create(struct dm_space_map *sm,
781 			  struct dm_transaction_manager *tm,
782 			  dm_block_t nr_blocks,
783 			  dm_block_t superblock)
784 {
785 	int r;
786 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
787 
788 	smm->begin = superblock + 1;
789 	smm->recursion_count = 0;
790 	smm->allocated_this_transaction = 0;
791 	brb_init(&smm->uncommitted);
792 	threshold_init(&smm->threshold);
793 
794 	memcpy(&smm->sm, &bootstrap_ops, sizeof(smm->sm));
795 
796 	r = sm_ll_new_metadata(&smm->ll, tm);
797 	if (!r) {
798 		if (nr_blocks > DM_SM_METADATA_MAX_BLOCKS)
799 			nr_blocks = DM_SM_METADATA_MAX_BLOCKS;
800 		r = sm_ll_extend(&smm->ll, nr_blocks);
801 	}
802 	memcpy(&smm->sm, &ops, sizeof(smm->sm));
803 	if (r)
804 		return r;
805 
806 	/*
807 	 * Now we need to update the newly created data structures with the
808 	 * allocated blocks that they were built from.
809 	 */
810 	r = add_bop(smm, BOP_INC, superblock, smm->begin);
811 	if (r)
812 		return r;
813 
814 	r = apply_bops(smm);
815 	if (r) {
816 		DMERR("%s: apply_bops failed", __func__);
817 		return r;
818 	}
819 
820 	return sm_metadata_commit(sm);
821 }
822 
dm_sm_metadata_open(struct dm_space_map * sm,struct dm_transaction_manager * tm,void * root_le,size_t len)823 int dm_sm_metadata_open(struct dm_space_map *sm,
824 			struct dm_transaction_manager *tm,
825 			void *root_le, size_t len)
826 {
827 	int r;
828 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
829 
830 	r = sm_ll_open_metadata(&smm->ll, tm, root_le, len);
831 	if (r)
832 		return r;
833 
834 	smm->begin = 0;
835 	smm->recursion_count = 0;
836 	smm->allocated_this_transaction = 0;
837 	brb_init(&smm->uncommitted);
838 	threshold_init(&smm->threshold);
839 
840 	memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll));
841 	return 0;
842 }
843