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PM / sleep: Asynchronous threads for suspend_noirq
[linux/fpc-iii.git] / drivers / md / bcache / extents.c
blob416d1a3e028e03a34a9d03e31b9e6fa583c9b357
1 /*
2 * Copyright (C) 2010 Kent Overstreet <kent.overstreet@gmail.com>
3 *
4 * Uses a block device as cache for other block devices; optimized for SSDs.
5 * All allocation is done in buckets, which should match the erase block size
6 * of the device.
7 *
8 * Buckets containing cached data are kept on a heap sorted by priority;
9 * bucket priority is increased on cache hit, and periodically all the buckets
10 * on the heap have their priority scaled down. This currently is just used as
11 * an LRU but in the future should allow for more intelligent heuristics.
12 *
13 * Buckets have an 8 bit counter; freeing is accomplished by incrementing the
14 * counter. Garbage collection is used to remove stale pointers.
15 *
16 * Indexing is done via a btree; nodes are not necessarily fully sorted, rather
17 * as keys are inserted we only sort the pages that have not yet been written.
18 * When garbage collection is run, we resort the entire node.
19 *
20 * All configuration is done via sysfs; see Documentation/bcache.txt.
21 */
22
23 #include "bcache.h"
24 #include "btree.h"
25 #include "debug.h"
26 #include "extents.h"
27 #include "writeback.h"
28
29 static void sort_key_next(struct btree_iter *iter,
30 struct btree_iter_set *i)
31 {
32 i->k = bkey_next(i->k);
33
34 if (i->k == i->end)
35 *i = iter->data[--iter->used];
36 }
37
38 static bool bch_key_sort_cmp(struct btree_iter_set l,
39 struct btree_iter_set r)
40 {
41 int64_t c = bkey_cmp(l.k, r.k);
42
43 return c ? c > 0 : l.k < r.k;
44 }
45
46 static bool __ptr_invalid(struct cache_set *c, const struct bkey *k)
47 {
48 unsigned i;
49
50 for (i = 0; i < KEY_PTRS(k); i++)
51 if (ptr_available(c, k, i)) {
52 struct cache *ca = PTR_CACHE(c, k, i);
53 size_t bucket = PTR_BUCKET_NR(c, k, i);
54 size_t r = bucket_remainder(c, PTR_OFFSET(k, i));
55
56 if (KEY_SIZE(k) + r > c->sb.bucket_size ||
57 bucket < ca->sb.first_bucket ||
58 bucket >= ca->sb.nbuckets)
59 return true;
60 }
61
62 return false;
63 }
64
65 /* Common among btree and extent ptrs */
66
67 static const char *bch_ptr_status(struct cache_set *c, const struct bkey *k)
68 {
69 unsigned i;
70
71 for (i = 0; i < KEY_PTRS(k); i++)
72 if (ptr_available(c, k, i)) {
73 struct cache *ca = PTR_CACHE(c, k, i);
74 size_t bucket = PTR_BUCKET_NR(c, k, i);
75 size_t r = bucket_remainder(c, PTR_OFFSET(k, i));
76
77 if (KEY_SIZE(k) + r > c->sb.bucket_size)
78 return "bad, length too big";
79 if (bucket < ca->sb.first_bucket)
80 return "bad, short offset";
81 if (bucket >= ca->sb.nbuckets)
82 return "bad, offset past end of device";
83 if (ptr_stale(c, k, i))
84 return "stale";
85 }
86
87 if (!bkey_cmp(k, &ZERO_KEY))
88 return "bad, null key";
89 if (!KEY_PTRS(k))
90 return "bad, no pointers";
91 if (!KEY_SIZE(k))
92 return "zeroed key";
93 return "";
94 }
95
96 void bch_extent_to_text(char *buf, size_t size, const struct bkey *k)
97 {
98 unsigned i = 0;
99 char *out = buf, *end = buf + size;
100
101 #define p(...) (out += scnprintf(out, end - out, __VA_ARGS__))
102
103 p("%llu:%llu len %llu -> [", KEY_INODE(k), KEY_START(k), KEY_SIZE(k));
104
105 for (i = 0; i < KEY_PTRS(k); i++) {
106 if (i)
107 p(", ");
108
109 if (PTR_DEV(k, i) == PTR_CHECK_DEV)
110 p("check dev");
111 else
112 p("%llu:%llu gen %llu", PTR_DEV(k, i),
113 PTR_OFFSET(k, i), PTR_GEN(k, i));
114 }
115
116 p("]");
117
118 if (KEY_DIRTY(k))
119 p(" dirty");
120 if (KEY_CSUM(k))
121 p(" cs%llu %llx", KEY_CSUM(k), k->ptr[1]);
122 #undef p
123 }
124
125 static void bch_bkey_dump(struct btree_keys *keys, const struct bkey *k)
126 {
127 struct btree *b = container_of(keys, struct btree, keys);
128 unsigned j;
129 char buf[80];
130
131 bch_extent_to_text(buf, sizeof(buf), k);
132 printk(" %s", buf);
133
134 for (j = 0; j < KEY_PTRS(k); j++) {
135 size_t n = PTR_BUCKET_NR(b->c, k, j);
136 printk(" bucket %zu", n);
137
138 if (n >= b->c->sb.first_bucket && n < b->c->sb.nbuckets)
139 printk(" prio %i",
140 PTR_BUCKET(b->c, k, j)->prio);
141 }
142
143 printk(" %s\n", bch_ptr_status(b->c, k));
144 }
145
146 /* Btree ptrs */
147
148 bool __bch_btree_ptr_invalid(struct cache_set *c, const struct bkey *k)
149 {
150 char buf[80];
151
152 if (!KEY_PTRS(k) || !KEY_SIZE(k) || KEY_DIRTY(k))
153 goto bad;
154
155 if (__ptr_invalid(c, k))
156 goto bad;
157
158 return false;
159 bad:
160 bch_extent_to_text(buf, sizeof(buf), k);
161 cache_bug(c, "spotted btree ptr %s: %s", buf, bch_ptr_status(c, k));
162 return true;
163 }
164
165 static bool bch_btree_ptr_invalid(struct btree_keys *bk, const struct bkey *k)
166 {
167 struct btree *b = container_of(bk, struct btree, keys);
168 return __bch_btree_ptr_invalid(b->c, k);
169 }
170
171 static bool btree_ptr_bad_expensive(struct btree *b, const struct bkey *k)
172 {
173 unsigned i;
174 char buf[80];
175 struct bucket *g;
176
177 if (mutex_trylock(&b->c->bucket_lock)) {
178 for (i = 0; i < KEY_PTRS(k); i++)
179 if (ptr_available(b->c, k, i)) {
180 g = PTR_BUCKET(b->c, k, i);
181
182 if (KEY_DIRTY(k) ||
183 g->prio != BTREE_PRIO ||
184 (b->c->gc_mark_valid &&
185 GC_MARK(g) != GC_MARK_METADATA))
186 goto err;
187 }
188
189 mutex_unlock(&b->c->bucket_lock);
190 }
191
192 return false;
193 err:
194 mutex_unlock(&b->c->bucket_lock);
195 bch_extent_to_text(buf, sizeof(buf), k);
196 btree_bug(b,
197 "inconsistent btree pointer %s: bucket %zi pin %i prio %i gen %i last_gc %i mark %llu gc_gen %i",
198 buf, PTR_BUCKET_NR(b->c, k, i), atomic_read(&g->pin),
199 g->prio, g->gen, g->last_gc, GC_MARK(g), g->gc_gen);
200 return true;
201 }
202
203 static bool bch_btree_ptr_bad(struct btree_keys *bk, const struct bkey *k)
204 {
205 struct btree *b = container_of(bk, struct btree, keys);
206 unsigned i;
207
208 if (!bkey_cmp(k, &ZERO_KEY) ||
209 !KEY_PTRS(k) ||
210 bch_ptr_invalid(bk, k))
211 return true;
212
213 for (i = 0; i < KEY_PTRS(k); i++)
214 if (!ptr_available(b->c, k, i) ||
215 ptr_stale(b->c, k, i))
216 return true;
217
218 if (expensive_debug_checks(b->c) &&
219 btree_ptr_bad_expensive(b, k))
220 return true;
221
222 return false;
223 }
224
225 static bool bch_btree_ptr_insert_fixup(struct btree_keys *bk,
226 struct bkey *insert,
227 struct btree_iter *iter,
228 struct bkey *replace_key)
229 {
230 struct btree *b = container_of(bk, struct btree, keys);
231
232 if (!KEY_OFFSET(insert))
233 btree_current_write(b)->prio_blocked++;
234
235 return false;
236 }
237
238 const struct btree_keys_ops bch_btree_keys_ops = {
239 .sort_cmp = bch_key_sort_cmp,
240 .insert_fixup = bch_btree_ptr_insert_fixup,
241 .key_invalid = bch_btree_ptr_invalid,
242 .key_bad = bch_btree_ptr_bad,
243 .key_to_text = bch_extent_to_text,
244 .key_dump = bch_bkey_dump,
245 };
246
247 /* Extents */
248
249 /*
250 * Returns true if l > r - unless l == r, in which case returns true if l is
251 * older than r.
252 *
253 * Necessary for btree_sort_fixup() - if there are multiple keys that compare
254 * equal in different sets, we have to process them newest to oldest.
255 */
256 static bool bch_extent_sort_cmp(struct btree_iter_set l,
257 struct btree_iter_set r)
258 {
259 int64_t c = bkey_cmp(&START_KEY(l.k), &START_KEY(r.k));
260
261 return c ? c > 0 : l.k < r.k;
262 }
263
264 static struct bkey *bch_extent_sort_fixup(struct btree_iter *iter,
265 struct bkey *tmp)
266 {
267 while (iter->used > 1) {
268 struct btree_iter_set *top = iter->data, *i = top + 1;
269
270 if (iter->used > 2 &&
271 bch_extent_sort_cmp(i[0], i[1]))
272 i++;
273
274 if (bkey_cmp(top->k, &START_KEY(i->k)) <= 0)
275 break;
276
277 if (!KEY_SIZE(i->k)) {
278 sort_key_next(iter, i);
279 heap_sift(iter, i - top, bch_extent_sort_cmp);
280 continue;
281 }
282
283 if (top->k > i->k) {
284 if (bkey_cmp(top->k, i->k) >= 0)
285 sort_key_next(iter, i);
286 else
287 bch_cut_front(top->k, i->k);
288
289 heap_sift(iter, i - top, bch_extent_sort_cmp);
290 } else {
291 /* can't happen because of comparison func */
292 BUG_ON(!bkey_cmp(&START_KEY(top->k), &START_KEY(i->k)));
293
294 if (bkey_cmp(i->k, top->k) < 0) {
295 bkey_copy(tmp, top->k);
296
297 bch_cut_back(&START_KEY(i->k), tmp);
298 bch_cut_front(i->k, top->k);
299 heap_sift(iter, 0, bch_extent_sort_cmp);
300
301 return tmp;
302 } else {
303 bch_cut_back(&START_KEY(i->k), top->k);
304 }
305 }
306 }
307
308 return NULL;
309 }
310
311 static bool bch_extent_insert_fixup(struct btree_keys *b,
312 struct bkey *insert,
313 struct btree_iter *iter,
314 struct bkey *replace_key)
315 {
316 struct cache_set *c = container_of(b, struct btree, keys)->c;
317
318 void subtract_dirty(struct bkey *k, uint64_t offset, int sectors)
319 {
320 if (KEY_DIRTY(k))
321 bcache_dev_sectors_dirty_add(c, KEY_INODE(k),
322 offset, -sectors);
323 }
324
325 uint64_t old_offset;
326 unsigned old_size, sectors_found = 0;
327
328 BUG_ON(!KEY_OFFSET(insert));
329 BUG_ON(!KEY_SIZE(insert));
330
331 while (1) {
332 struct bkey *k = bch_btree_iter_next(iter);
333 if (!k)
334 break;
335
336 if (bkey_cmp(&START_KEY(k), insert) >= 0) {
337 if (KEY_SIZE(k))
338 break;
339 else
340 continue;
341 }
342
343 if (bkey_cmp(k, &START_KEY(insert)) <= 0)
344 continue;
345
346 old_offset = KEY_START(k);
347 old_size = KEY_SIZE(k);
348
349 /*
350 * We might overlap with 0 size extents; we can't skip these
351 * because if they're in the set we're inserting to we have to
352 * adjust them so they don't overlap with the key we're
353 * inserting. But we don't want to check them for replace
354 * operations.
355 */
356
357 if (replace_key && KEY_SIZE(k)) {
358 /*
359 * k might have been split since we inserted/found the
360 * key we're replacing
361 */
362 unsigned i;
363 uint64_t offset = KEY_START(k) -
364 KEY_START(replace_key);
365
366 /* But it must be a subset of the replace key */
367 if (KEY_START(k) < KEY_START(replace_key) ||
368 KEY_OFFSET(k) > KEY_OFFSET(replace_key))
369 goto check_failed;
370
371 /* We didn't find a key that we were supposed to */
372 if (KEY_START(k) > KEY_START(insert) + sectors_found)
373 goto check_failed;
374
375 if (!bch_bkey_equal_header(k, replace_key))
376 goto check_failed;
377
378 /* skip past gen */
379 offset <<= 8;
380
381 BUG_ON(!KEY_PTRS(replace_key));
382
383 for (i = 0; i < KEY_PTRS(replace_key); i++)
384 if (k->ptr[i] != replace_key->ptr[i] + offset)
385 goto check_failed;
386
387 sectors_found = KEY_OFFSET(k) - KEY_START(insert);
388 }
389
390 if (bkey_cmp(insert, k) < 0 &&
391 bkey_cmp(&START_KEY(insert), &START_KEY(k)) > 0) {
392 /*
393 * We overlapped in the middle of an existing key: that
394 * means we have to split the old key. But we have to do
395 * slightly different things depending on whether the
396 * old key has been written out yet.
397 */
398
399 struct bkey *top;
400
401 subtract_dirty(k, KEY_START(insert), KEY_SIZE(insert));
402
403 if (bkey_written(b, k)) {
404 /*
405 * We insert a new key to cover the top of the
406 * old key, and the old key is modified in place
407 * to represent the bottom split.
408 *
409 * It's completely arbitrary whether the new key
410 * is the top or the bottom, but it has to match
411 * up with what btree_sort_fixup() does - it
412 * doesn't check for this kind of overlap, it
413 * depends on us inserting a new key for the top
414 * here.
415 */
416 top = bch_bset_search(b, bset_tree_last(b),
417 insert);
418 bch_bset_insert(b, top, k);
419 } else {
420 BKEY_PADDED(key) temp;
421 bkey_copy(&temp.key, k);
422 bch_bset_insert(b, k, &temp.key);
423 top = bkey_next(k);
424 }
425
426 bch_cut_front(insert, top);
427 bch_cut_back(&START_KEY(insert), k);
428 bch_bset_fix_invalidated_key(b, k);
429 goto out;
430 }
431
432 if (bkey_cmp(insert, k) < 0) {
433 bch_cut_front(insert, k);
434 } else {
435 if (bkey_cmp(&START_KEY(insert), &START_KEY(k)) > 0)
436 old_offset = KEY_START(insert);
437
438 if (bkey_written(b, k) &&
439 bkey_cmp(&START_KEY(insert), &START_KEY(k)) <= 0) {
440 /*
441 * Completely overwrote, so we don't have to
442 * invalidate the binary search tree
443 */
444 bch_cut_front(k, k);
445 } else {
446 __bch_cut_back(&START_KEY(insert), k);
447 bch_bset_fix_invalidated_key(b, k);
448 }
449 }
450
451 subtract_dirty(k, old_offset, old_size - KEY_SIZE(k));
452 }
453
454 check_failed:
455 if (replace_key) {
456 if (!sectors_found) {
457 return true;
458 } else if (sectors_found < KEY_SIZE(insert)) {
459 SET_KEY_OFFSET(insert, KEY_OFFSET(insert) -
460 (KEY_SIZE(insert) - sectors_found));
461 SET_KEY_SIZE(insert, sectors_found);
462 }
463 }
464 out:
465 if (KEY_DIRTY(insert))
466 bcache_dev_sectors_dirty_add(c, KEY_INODE(insert),
467 KEY_START(insert),
468 KEY_SIZE(insert));
469
470 return false;
471 }
472
473 static bool bch_extent_invalid(struct btree_keys *bk, const struct bkey *k)
474 {
475 struct btree *b = container_of(bk, struct btree, keys);
476 char buf[80];
477
478 if (!KEY_SIZE(k))
479 return true;
480
481 if (KEY_SIZE(k) > KEY_OFFSET(k))
482 goto bad;
483
484 if (__ptr_invalid(b->c, k))
485 goto bad;
486
487 return false;
488 bad:
489 bch_extent_to_text(buf, sizeof(buf), k);
490 cache_bug(b->c, "spotted extent %s: %s", buf, bch_ptr_status(b->c, k));
491 return true;
492 }
493
494 static bool bch_extent_bad_expensive(struct btree *b, const struct bkey *k,
495 unsigned ptr)
496 {
497 struct bucket *g = PTR_BUCKET(b->c, k, ptr);
498 char buf[80];
499
500 if (mutex_trylock(&b->c->bucket_lock)) {
501 if (b->c->gc_mark_valid &&
502 ((GC_MARK(g) != GC_MARK_DIRTY &&
503 KEY_DIRTY(k)) ||
504 GC_MARK(g) == GC_MARK_METADATA))
505 goto err;
506
507 if (g->prio == BTREE_PRIO)
508 goto err;
509
510 mutex_unlock(&b->c->bucket_lock);
511 }
512
513 return false;
514 err:
515 mutex_unlock(&b->c->bucket_lock);
516 bch_extent_to_text(buf, sizeof(buf), k);
517 btree_bug(b,
518 "inconsistent extent pointer %s:\nbucket %zu pin %i prio %i gen %i last_gc %i mark %llu gc_gen %i",
519 buf, PTR_BUCKET_NR(b->c, k, ptr), atomic_read(&g->pin),
520 g->prio, g->gen, g->last_gc, GC_MARK(g), g->gc_gen);
521 return true;
522 }
523
524 static bool bch_extent_bad(struct btree_keys *bk, const struct bkey *k)
525 {
526 struct btree *b = container_of(bk, struct btree, keys);
527 struct bucket *g;
528 unsigned i, stale;
529
530 if (!KEY_PTRS(k) ||
531 bch_extent_invalid(bk, k))
532 return true;
533
534 for (i = 0; i < KEY_PTRS(k); i++)
535 if (!ptr_available(b->c, k, i))
536 return true;
537
538 if (!expensive_debug_checks(b->c) && KEY_DIRTY(k))
539 return false;
540
541 for (i = 0; i < KEY_PTRS(k); i++) {
542 g = PTR_BUCKET(b->c, k, i);
543 stale = ptr_stale(b->c, k, i);
544
545 btree_bug_on(stale > 96, b,
546 "key too stale: %i, need_gc %u",
547 stale, b->c->need_gc);
548
549 btree_bug_on(stale && KEY_DIRTY(k) && KEY_SIZE(k),
550 b, "stale dirty pointer");
551
552 if (stale)
553 return true;
554
555 if (expensive_debug_checks(b->c) &&
556 bch_extent_bad_expensive(b, k, i))
557 return true;
558 }
559
560 return false;
561 }
562
563 static uint64_t merge_chksums(struct bkey *l, struct bkey *r)
564 {
565 return (l->ptr[KEY_PTRS(l)] + r->ptr[KEY_PTRS(r)]) &
566 ~((uint64_t)1 << 63);
567 }
568
569 static bool bch_extent_merge(struct btree_keys *bk, struct bkey *l, struct bkey *r)
570 {
571 struct btree *b = container_of(bk, struct btree, keys);
572 unsigned i;
573
574 if (key_merging_disabled(b->c))
575 return false;
576
577 for (i = 0; i < KEY_PTRS(l); i++)
578 if (l->ptr[i] + PTR(0, KEY_SIZE(l), 0) != r->ptr[i] ||
579 PTR_BUCKET_NR(b->c, l, i) != PTR_BUCKET_NR(b->c, r, i))
580 return false;
581
582 /* Keys with no pointers aren't restricted to one bucket and could
583 * overflow KEY_SIZE
584 */
585 if (KEY_SIZE(l) + KEY_SIZE(r) > USHRT_MAX) {
586 SET_KEY_OFFSET(l, KEY_OFFSET(l) + USHRT_MAX - KEY_SIZE(l));
587 SET_KEY_SIZE(l, USHRT_MAX);
588
589 bch_cut_front(l, r);
590 return false;
591 }
592
593 if (KEY_CSUM(l)) {
594 if (KEY_CSUM(r))
595 l->ptr[KEY_PTRS(l)] = merge_chksums(l, r);
596 else
597 SET_KEY_CSUM(l, 0);
598 }
599
600 SET_KEY_OFFSET(l, KEY_OFFSET(l) + KEY_SIZE(r));
601 SET_KEY_SIZE(l, KEY_SIZE(l) + KEY_SIZE(r));
602
603 return true;
604 }
605
606 const struct btree_keys_ops bch_extent_keys_ops = {
607 .sort_cmp = bch_extent_sort_cmp,
608 .sort_fixup = bch_extent_sort_fixup,
609 .insert_fixup = bch_extent_insert_fixup,
610 .key_invalid = bch_extent_invalid,
611 .key_bad = bch_extent_bad,
612 .key_merge = bch_extent_merge,
613 .key_to_text = bch_extent_to_text,
614 .key_dump = bch_bkey_dump,
615 .is_extents = true,
616 };
Linux with added FPC-III support