Loading...
Note: File does not exist in v3.1.
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2010 Kent Overstreet <kent.overstreet@gmail.com>
4 *
5 * Uses a block device as cache for other block devices; optimized for SSDs.
6 * All allocation is done in buckets, which should match the erase block size
7 * of the device.
8 *
9 * Buckets containing cached data are kept on a heap sorted by priority;
10 * bucket priority is increased on cache hit, and periodically all the buckets
11 * on the heap have their priority scaled down. This currently is just used as
12 * an LRU but in the future should allow for more intelligent heuristics.
13 *
14 * Buckets have an 8 bit counter; freeing is accomplished by incrementing the
15 * counter. Garbage collection is used to remove stale pointers.
16 *
17 * Indexing is done via a btree; nodes are not necessarily fully sorted, rather
18 * as keys are inserted we only sort the pages that have not yet been written.
19 * When garbage collection is run, we resort the entire node.
20 *
21 * All configuration is done via sysfs; see Documentation/admin-guide/bcache.rst.
22 */
23
24#include "bcache.h"
25#include "btree.h"
26#include "debug.h"
27#include "extents.h"
28
29#include <linux/slab.h>
30#include <linux/bitops.h>
31#include <linux/hash.h>
32#include <linux/kthread.h>
33#include <linux/prefetch.h>
34#include <linux/random.h>
35#include <linux/rcupdate.h>
36#include <linux/sched/clock.h>
37#include <linux/rculist.h>
38#include <linux/delay.h>
39#include <trace/events/bcache.h>
40
41/*
42 * Todo:
43 * register_bcache: Return errors out to userspace correctly
44 *
45 * Writeback: don't undirty key until after a cache flush
46 *
47 * Create an iterator for key pointers
48 *
49 * On btree write error, mark bucket such that it won't be freed from the cache
50 *
51 * Journalling:
52 * Check for bad keys in replay
53 * Propagate barriers
54 * Refcount journal entries in journal_replay
55 *
56 * Garbage collection:
57 * Finish incremental gc
58 * Gc should free old UUIDs, data for invalid UUIDs
59 *
60 * Provide a way to list backing device UUIDs we have data cached for, and
61 * probably how long it's been since we've seen them, and a way to invalidate
62 * dirty data for devices that will never be attached again
63 *
64 * Keep 1 min/5 min/15 min statistics of how busy a block device has been, so
65 * that based on that and how much dirty data we have we can keep writeback
66 * from being starved
67 *
68 * Add a tracepoint or somesuch to watch for writeback starvation
69 *
70 * When btree depth > 1 and splitting an interior node, we have to make sure
71 * alloc_bucket() cannot fail. This should be true but is not completely
72 * obvious.
73 *
74 * Plugging?
75 *
76 * If data write is less than hard sector size of ssd, round up offset in open
77 * bucket to the next whole sector
78 *
79 * Superblock needs to be fleshed out for multiple cache devices
80 *
81 * Add a sysfs tunable for the number of writeback IOs in flight
82 *
83 * Add a sysfs tunable for the number of open data buckets
84 *
85 * IO tracking: Can we track when one process is doing io on behalf of another?
86 * IO tracking: Don't use just an average, weigh more recent stuff higher
87 *
88 * Test module load/unload
89 */
90
91#define MAX_NEED_GC 64
92#define MAX_SAVE_PRIO 72
93#define MAX_GC_TIMES 100
94#define MIN_GC_NODES 100
95#define GC_SLEEP_MS 100
96
97#define PTR_DIRTY_BIT (((uint64_t) 1 << 36))
98
99#define PTR_HASH(c, k) \
100 (((k)->ptr[0] >> c->bucket_bits) | PTR_GEN(k, 0))
101
102#define insert_lock(s, b) ((b)->level <= (s)->lock)
103
104/*
105 * These macros are for recursing down the btree - they handle the details of
106 * locking and looking up nodes in the cache for you. They're best treated as
107 * mere syntax when reading code that uses them.
108 *
109 * op->lock determines whether we take a read or a write lock at a given depth.
110 * If you've got a read lock and find that you need a write lock (i.e. you're
111 * going to have to split), set op->lock and return -EINTR; btree_root() will
112 * call you again and you'll have the correct lock.
113 */
114
115/**
116 * btree - recurse down the btree on a specified key
117 * @fn: function to call, which will be passed the child node
118 * @key: key to recurse on
119 * @b: parent btree node
120 * @op: pointer to struct btree_op
121 */
122#define btree(fn, key, b, op, ...) \
123({ \
124 int _r, l = (b)->level - 1; \
125 bool _w = l <= (op)->lock; \
126 struct btree *_child = bch_btree_node_get((b)->c, op, key, l, \
127 _w, b); \
128 if (!IS_ERR(_child)) { \
129 _r = bch_btree_ ## fn(_child, op, ##__VA_ARGS__); \
130 rw_unlock(_w, _child); \
131 } else \
132 _r = PTR_ERR(_child); \
133 _r; \
134})
135
136/**
137 * btree_root - call a function on the root of the btree
138 * @fn: function to call, which will be passed the child node
139 * @c: cache set
140 * @op: pointer to struct btree_op
141 */
142#define btree_root(fn, c, op, ...) \
143({ \
144 int _r = -EINTR; \
145 do { \
146 struct btree *_b = (c)->root; \
147 bool _w = insert_lock(op, _b); \
148 rw_lock(_w, _b, _b->level); \
149 if (_b == (c)->root && \
150 _w == insert_lock(op, _b)) { \
151 _r = bch_btree_ ## fn(_b, op, ##__VA_ARGS__); \
152 } \
153 rw_unlock(_w, _b); \
154 bch_cannibalize_unlock(c); \
155 if (_r == -EINTR) \
156 schedule(); \
157 } while (_r == -EINTR); \
158 \
159 finish_wait(&(c)->btree_cache_wait, &(op)->wait); \
160 _r; \
161})
162
163static inline struct bset *write_block(struct btree *b)
164{
165 return ((void *) btree_bset_first(b)) + b->written * block_bytes(b->c);
166}
167
168static void bch_btree_init_next(struct btree *b)
169{
170 /* If not a leaf node, always sort */
171 if (b->level && b->keys.nsets)
172 bch_btree_sort(&b->keys, &b->c->sort);
173 else
174 bch_btree_sort_lazy(&b->keys, &b->c->sort);
175
176 if (b->written < btree_blocks(b))
177 bch_bset_init_next(&b->keys, write_block(b),
178 bset_magic(&b->c->sb));
179
180}
181
182/* Btree key manipulation */
183
184void bkey_put(struct cache_set *c, struct bkey *k)
185{
186 unsigned int i;
187
188 for (i = 0; i < KEY_PTRS(k); i++)
189 if (ptr_available(c, k, i))
190 atomic_dec_bug(&PTR_BUCKET(c, k, i)->pin);
191}
192
193/* Btree IO */
194
195static uint64_t btree_csum_set(struct btree *b, struct bset *i)
196{
197 uint64_t crc = b->key.ptr[0];
198 void *data = (void *) i + 8, *end = bset_bkey_last(i);
199
200 crc = bch_crc64_update(crc, data, end - data);
201 return crc ^ 0xffffffffffffffffULL;
202}
203
204void bch_btree_node_read_done(struct btree *b)
205{
206 const char *err = "bad btree header";
207 struct bset *i = btree_bset_first(b);
208 struct btree_iter *iter;
209
210 /*
211 * c->fill_iter can allocate an iterator with more memory space
212 * than static MAX_BSETS.
213 * See the comment arount cache_set->fill_iter.
214 */
215 iter = mempool_alloc(&b->c->fill_iter, GFP_NOIO);
216 iter->size = b->c->sb.bucket_size / b->c->sb.block_size;
217 iter->used = 0;
218
219#ifdef CONFIG_BCACHE_DEBUG
220 iter->b = &b->keys;
221#endif
222
223 if (!i->seq)
224 goto err;
225
226 for (;
227 b->written < btree_blocks(b) && i->seq == b->keys.set[0].data->seq;
228 i = write_block(b)) {
229 err = "unsupported bset version";
230 if (i->version > BCACHE_BSET_VERSION)
231 goto err;
232
233 err = "bad btree header";
234 if (b->written + set_blocks(i, block_bytes(b->c)) >
235 btree_blocks(b))
236 goto err;
237
238 err = "bad magic";
239 if (i->magic != bset_magic(&b->c->sb))
240 goto err;
241
242 err = "bad checksum";
243 switch (i->version) {
244 case 0:
245 if (i->csum != csum_set(i))
246 goto err;
247 break;
248 case BCACHE_BSET_VERSION:
249 if (i->csum != btree_csum_set(b, i))
250 goto err;
251 break;
252 }
253
254 err = "empty set";
255 if (i != b->keys.set[0].data && !i->keys)
256 goto err;
257
258 bch_btree_iter_push(iter, i->start, bset_bkey_last(i));
259
260 b->written += set_blocks(i, block_bytes(b->c));
261 }
262
263 err = "corrupted btree";
264 for (i = write_block(b);
265 bset_sector_offset(&b->keys, i) < KEY_SIZE(&b->key);
266 i = ((void *) i) + block_bytes(b->c))
267 if (i->seq == b->keys.set[0].data->seq)
268 goto err;
269
270 bch_btree_sort_and_fix_extents(&b->keys, iter, &b->c->sort);
271
272 i = b->keys.set[0].data;
273 err = "short btree key";
274 if (b->keys.set[0].size &&
275 bkey_cmp(&b->key, &b->keys.set[0].end) < 0)
276 goto err;
277
278 if (b->written < btree_blocks(b))
279 bch_bset_init_next(&b->keys, write_block(b),
280 bset_magic(&b->c->sb));
281out:
282 mempool_free(iter, &b->c->fill_iter);
283 return;
284err:
285 set_btree_node_io_error(b);
286 bch_cache_set_error(b->c, "%s at bucket %zu, block %u, %u keys",
287 err, PTR_BUCKET_NR(b->c, &b->key, 0),
288 bset_block_offset(b, i), i->keys);
289 goto out;
290}
291
292static void btree_node_read_endio(struct bio *bio)
293{
294 struct closure *cl = bio->bi_private;
295
296 closure_put(cl);
297}
298
299static void bch_btree_node_read(struct btree *b)
300{
301 uint64_t start_time = local_clock();
302 struct closure cl;
303 struct bio *bio;
304
305 trace_bcache_btree_read(b);
306
307 closure_init_stack(&cl);
308
309 bio = bch_bbio_alloc(b->c);
310 bio->bi_iter.bi_size = KEY_SIZE(&b->key) << 9;
311 bio->bi_end_io = btree_node_read_endio;
312 bio->bi_private = &cl;
313 bio->bi_opf = REQ_OP_READ | REQ_META;
314
315 bch_bio_map(bio, b->keys.set[0].data);
316
317 bch_submit_bbio(bio, b->c, &b->key, 0);
318 closure_sync(&cl);
319
320 if (bio->bi_status)
321 set_btree_node_io_error(b);
322
323 bch_bbio_free(bio, b->c);
324
325 if (btree_node_io_error(b))
326 goto err;
327
328 bch_btree_node_read_done(b);
329 bch_time_stats_update(&b->c->btree_read_time, start_time);
330
331 return;
332err:
333 bch_cache_set_error(b->c, "io error reading bucket %zu",
334 PTR_BUCKET_NR(b->c, &b->key, 0));
335}
336
337static void btree_complete_write(struct btree *b, struct btree_write *w)
338{
339 if (w->prio_blocked &&
340 !atomic_sub_return(w->prio_blocked, &b->c->prio_blocked))
341 wake_up_allocators(b->c);
342
343 if (w->journal) {
344 atomic_dec_bug(w->journal);
345 __closure_wake_up(&b->c->journal.wait);
346 }
347
348 w->prio_blocked = 0;
349 w->journal = NULL;
350}
351
352static void btree_node_write_unlock(struct closure *cl)
353{
354 struct btree *b = container_of(cl, struct btree, io);
355
356 up(&b->io_mutex);
357}
358
359static void __btree_node_write_done(struct closure *cl)
360{
361 struct btree *b = container_of(cl, struct btree, io);
362 struct btree_write *w = btree_prev_write(b);
363
364 bch_bbio_free(b->bio, b->c);
365 b->bio = NULL;
366 btree_complete_write(b, w);
367
368 if (btree_node_dirty(b))
369 schedule_delayed_work(&b->work, 30 * HZ);
370
371 closure_return_with_destructor(cl, btree_node_write_unlock);
372}
373
374static void btree_node_write_done(struct closure *cl)
375{
376 struct btree *b = container_of(cl, struct btree, io);
377
378 bio_free_pages(b->bio);
379 __btree_node_write_done(cl);
380}
381
382static void btree_node_write_endio(struct bio *bio)
383{
384 struct closure *cl = bio->bi_private;
385 struct btree *b = container_of(cl, struct btree, io);
386
387 if (bio->bi_status)
388 set_btree_node_io_error(b);
389
390 bch_bbio_count_io_errors(b->c, bio, bio->bi_status, "writing btree");
391 closure_put(cl);
392}
393
394static void do_btree_node_write(struct btree *b)
395{
396 struct closure *cl = &b->io;
397 struct bset *i = btree_bset_last(b);
398 BKEY_PADDED(key) k;
399
400 i->version = BCACHE_BSET_VERSION;
401 i->csum = btree_csum_set(b, i);
402
403 BUG_ON(b->bio);
404 b->bio = bch_bbio_alloc(b->c);
405
406 b->bio->bi_end_io = btree_node_write_endio;
407 b->bio->bi_private = cl;
408 b->bio->bi_iter.bi_size = roundup(set_bytes(i), block_bytes(b->c));
409 b->bio->bi_opf = REQ_OP_WRITE | REQ_META | REQ_FUA;
410 bch_bio_map(b->bio, i);
411
412 /*
413 * If we're appending to a leaf node, we don't technically need FUA -
414 * this write just needs to be persisted before the next journal write,
415 * which will be marked FLUSH|FUA.
416 *
417 * Similarly if we're writing a new btree root - the pointer is going to
418 * be in the next journal entry.
419 *
420 * But if we're writing a new btree node (that isn't a root) or
421 * appending to a non leaf btree node, we need either FUA or a flush
422 * when we write the parent with the new pointer. FUA is cheaper than a
423 * flush, and writes appending to leaf nodes aren't blocking anything so
424 * just make all btree node writes FUA to keep things sane.
425 */
426
427 bkey_copy(&k.key, &b->key);
428 SET_PTR_OFFSET(&k.key, 0, PTR_OFFSET(&k.key, 0) +
429 bset_sector_offset(&b->keys, i));
430
431 if (!bch_bio_alloc_pages(b->bio, __GFP_NOWARN|GFP_NOWAIT)) {
432 struct bio_vec *bv;
433 void *addr = (void *) ((unsigned long) i & ~(PAGE_SIZE - 1));
434 struct bvec_iter_all iter_all;
435
436 bio_for_each_segment_all(bv, b->bio, iter_all) {
437 memcpy(page_address(bv->bv_page), addr, PAGE_SIZE);
438 addr += PAGE_SIZE;
439 }
440
441 bch_submit_bbio(b->bio, b->c, &k.key, 0);
442
443 continue_at(cl, btree_node_write_done, NULL);
444 } else {
445 /*
446 * No problem for multipage bvec since the bio is
447 * just allocated
448 */
449 b->bio->bi_vcnt = 0;
450 bch_bio_map(b->bio, i);
451
452 bch_submit_bbio(b->bio, b->c, &k.key, 0);
453
454 closure_sync(cl);
455 continue_at_nobarrier(cl, __btree_node_write_done, NULL);
456 }
457}
458
459void __bch_btree_node_write(struct btree *b, struct closure *parent)
460{
461 struct bset *i = btree_bset_last(b);
462
463 lockdep_assert_held(&b->write_lock);
464
465 trace_bcache_btree_write(b);
466
467 BUG_ON(current->bio_list);
468 BUG_ON(b->written >= btree_blocks(b));
469 BUG_ON(b->written && !i->keys);
470 BUG_ON(btree_bset_first(b)->seq != i->seq);
471 bch_check_keys(&b->keys, "writing");
472
473 cancel_delayed_work(&b->work);
474
475 /* If caller isn't waiting for write, parent refcount is cache set */
476 down(&b->io_mutex);
477 closure_init(&b->io, parent ?: &b->c->cl);
478
479 clear_bit(BTREE_NODE_dirty, &b->flags);
480 change_bit(BTREE_NODE_write_idx, &b->flags);
481
482 do_btree_node_write(b);
483
484 atomic_long_add(set_blocks(i, block_bytes(b->c)) * b->c->sb.block_size,
485 &PTR_CACHE(b->c, &b->key, 0)->btree_sectors_written);
486
487 b->written += set_blocks(i, block_bytes(b->c));
488}
489
490void bch_btree_node_write(struct btree *b, struct closure *parent)
491{
492 unsigned int nsets = b->keys.nsets;
493
494 lockdep_assert_held(&b->lock);
495
496 __bch_btree_node_write(b, parent);
497
498 /*
499 * do verify if there was more than one set initially (i.e. we did a
500 * sort) and we sorted down to a single set:
501 */
502 if (nsets && !b->keys.nsets)
503 bch_btree_verify(b);
504
505 bch_btree_init_next(b);
506}
507
508static void bch_btree_node_write_sync(struct btree *b)
509{
510 struct closure cl;
511
512 closure_init_stack(&cl);
513
514 mutex_lock(&b->write_lock);
515 bch_btree_node_write(b, &cl);
516 mutex_unlock(&b->write_lock);
517
518 closure_sync(&cl);
519}
520
521static void btree_node_write_work(struct work_struct *w)
522{
523 struct btree *b = container_of(to_delayed_work(w), struct btree, work);
524
525 mutex_lock(&b->write_lock);
526 if (btree_node_dirty(b))
527 __bch_btree_node_write(b, NULL);
528 mutex_unlock(&b->write_lock);
529}
530
531static void bch_btree_leaf_dirty(struct btree *b, atomic_t *journal_ref)
532{
533 struct bset *i = btree_bset_last(b);
534 struct btree_write *w = btree_current_write(b);
535
536 lockdep_assert_held(&b->write_lock);
537
538 BUG_ON(!b->written);
539 BUG_ON(!i->keys);
540
541 if (!btree_node_dirty(b))
542 schedule_delayed_work(&b->work, 30 * HZ);
543
544 set_btree_node_dirty(b);
545
546 if (journal_ref) {
547 if (w->journal &&
548 journal_pin_cmp(b->c, w->journal, journal_ref)) {
549 atomic_dec_bug(w->journal);
550 w->journal = NULL;
551 }
552
553 if (!w->journal) {
554 w->journal = journal_ref;
555 atomic_inc(w->journal);
556 }
557 }
558
559 /* Force write if set is too big */
560 if (set_bytes(i) > PAGE_SIZE - 48 &&
561 !current->bio_list)
562 bch_btree_node_write(b, NULL);
563}
564
565/*
566 * Btree in memory cache - allocation/freeing
567 * mca -> memory cache
568 */
569
570#define mca_reserve(c) (((c->root && c->root->level) \
571 ? c->root->level : 1) * 8 + 16)
572#define mca_can_free(c) \
573 max_t(int, 0, c->btree_cache_used - mca_reserve(c))
574
575static void mca_data_free(struct btree *b)
576{
577 BUG_ON(b->io_mutex.count != 1);
578
579 bch_btree_keys_free(&b->keys);
580
581 b->c->btree_cache_used--;
582 list_move(&b->list, &b->c->btree_cache_freed);
583}
584
585static void mca_bucket_free(struct btree *b)
586{
587 BUG_ON(btree_node_dirty(b));
588
589 b->key.ptr[0] = 0;
590 hlist_del_init_rcu(&b->hash);
591 list_move(&b->list, &b->c->btree_cache_freeable);
592}
593
594static unsigned int btree_order(struct bkey *k)
595{
596 return ilog2(KEY_SIZE(k) / PAGE_SECTORS ?: 1);
597}
598
599static void mca_data_alloc(struct btree *b, struct bkey *k, gfp_t gfp)
600{
601 if (!bch_btree_keys_alloc(&b->keys,
602 max_t(unsigned int,
603 ilog2(b->c->btree_pages),
604 btree_order(k)),
605 gfp)) {
606 b->c->btree_cache_used++;
607 list_move(&b->list, &b->c->btree_cache);
608 } else {
609 list_move(&b->list, &b->c->btree_cache_freed);
610 }
611}
612
613static struct btree *mca_bucket_alloc(struct cache_set *c,
614 struct bkey *k, gfp_t gfp)
615{
616 /*
617 * kzalloc() is necessary here for initialization,
618 * see code comments in bch_btree_keys_init().
619 */
620 struct btree *b = kzalloc(sizeof(struct btree), gfp);
621
622 if (!b)
623 return NULL;
624
625 init_rwsem(&b->lock);
626 lockdep_set_novalidate_class(&b->lock);
627 mutex_init(&b->write_lock);
628 lockdep_set_novalidate_class(&b->write_lock);
629 INIT_LIST_HEAD(&b->list);
630 INIT_DELAYED_WORK(&b->work, btree_node_write_work);
631 b->c = c;
632 sema_init(&b->io_mutex, 1);
633
634 mca_data_alloc(b, k, gfp);
635 return b;
636}
637
638static int mca_reap(struct btree *b, unsigned int min_order, bool flush)
639{
640 struct closure cl;
641
642 closure_init_stack(&cl);
643 lockdep_assert_held(&b->c->bucket_lock);
644
645 if (!down_write_trylock(&b->lock))
646 return -ENOMEM;
647
648 BUG_ON(btree_node_dirty(b) && !b->keys.set[0].data);
649
650 if (b->keys.page_order < min_order)
651 goto out_unlock;
652
653 if (!flush) {
654 if (btree_node_dirty(b))
655 goto out_unlock;
656
657 if (down_trylock(&b->io_mutex))
658 goto out_unlock;
659 up(&b->io_mutex);
660 }
661
662retry:
663 /*
664 * BTREE_NODE_dirty might be cleared in btree_flush_btree() by
665 * __bch_btree_node_write(). To avoid an extra flush, acquire
666 * b->write_lock before checking BTREE_NODE_dirty bit.
667 */
668 mutex_lock(&b->write_lock);
669 /*
670 * If this btree node is selected in btree_flush_write() by journal
671 * code, delay and retry until the node is flushed by journal code
672 * and BTREE_NODE_journal_flush bit cleared by btree_flush_write().
673 */
674 if (btree_node_journal_flush(b)) {
675 pr_debug("bnode %p is flushing by journal, retry", b);
676 mutex_unlock(&b->write_lock);
677 udelay(1);
678 goto retry;
679 }
680
681 if (btree_node_dirty(b))
682 __bch_btree_node_write(b, &cl);
683 mutex_unlock(&b->write_lock);
684
685 closure_sync(&cl);
686
687 /* wait for any in flight btree write */
688 down(&b->io_mutex);
689 up(&b->io_mutex);
690
691 return 0;
692out_unlock:
693 rw_unlock(true, b);
694 return -ENOMEM;
695}
696
697static unsigned long bch_mca_scan(struct shrinker *shrink,
698 struct shrink_control *sc)
699{
700 struct cache_set *c = container_of(shrink, struct cache_set, shrink);
701 struct btree *b, *t;
702 unsigned long i, nr = sc->nr_to_scan;
703 unsigned long freed = 0;
704 unsigned int btree_cache_used;
705
706 if (c->shrinker_disabled)
707 return SHRINK_STOP;
708
709 if (c->btree_cache_alloc_lock)
710 return SHRINK_STOP;
711
712 /* Return -1 if we can't do anything right now */
713 if (sc->gfp_mask & __GFP_IO)
714 mutex_lock(&c->bucket_lock);
715 else if (!mutex_trylock(&c->bucket_lock))
716 return -1;
717
718 /*
719 * It's _really_ critical that we don't free too many btree nodes - we
720 * have to always leave ourselves a reserve. The reserve is how we
721 * guarantee that allocating memory for a new btree node can always
722 * succeed, so that inserting keys into the btree can always succeed and
723 * IO can always make forward progress:
724 */
725 nr /= c->btree_pages;
726 nr = min_t(unsigned long, nr, mca_can_free(c));
727
728 i = 0;
729 btree_cache_used = c->btree_cache_used;
730 list_for_each_entry_safe(b, t, &c->btree_cache_freeable, list) {
731 if (nr <= 0)
732 goto out;
733
734 if (++i > 3 &&
735 !mca_reap(b, 0, false)) {
736 mca_data_free(b);
737 rw_unlock(true, b);
738 freed++;
739 }
740 nr--;
741 }
742
743 for (; (nr--) && i < btree_cache_used; i++) {
744 if (list_empty(&c->btree_cache))
745 goto out;
746
747 b = list_first_entry(&c->btree_cache, struct btree, list);
748 list_rotate_left(&c->btree_cache);
749
750 if (!b->accessed &&
751 !mca_reap(b, 0, false)) {
752 mca_bucket_free(b);
753 mca_data_free(b);
754 rw_unlock(true, b);
755 freed++;
756 } else
757 b->accessed = 0;
758 }
759out:
760 mutex_unlock(&c->bucket_lock);
761 return freed * c->btree_pages;
762}
763
764static unsigned long bch_mca_count(struct shrinker *shrink,
765 struct shrink_control *sc)
766{
767 struct cache_set *c = container_of(shrink, struct cache_set, shrink);
768
769 if (c->shrinker_disabled)
770 return 0;
771
772 if (c->btree_cache_alloc_lock)
773 return 0;
774
775 return mca_can_free(c) * c->btree_pages;
776}
777
778void bch_btree_cache_free(struct cache_set *c)
779{
780 struct btree *b;
781 struct closure cl;
782
783 closure_init_stack(&cl);
784
785 if (c->shrink.list.next)
786 unregister_shrinker(&c->shrink);
787
788 mutex_lock(&c->bucket_lock);
789
790#ifdef CONFIG_BCACHE_DEBUG
791 if (c->verify_data)
792 list_move(&c->verify_data->list, &c->btree_cache);
793
794 free_pages((unsigned long) c->verify_ondisk, ilog2(bucket_pages(c)));
795#endif
796
797 list_splice(&c->btree_cache_freeable,
798 &c->btree_cache);
799
800 while (!list_empty(&c->btree_cache)) {
801 b = list_first_entry(&c->btree_cache, struct btree, list);
802
803 /*
804 * This function is called by cache_set_free(), no I/O
805 * request on cache now, it is unnecessary to acquire
806 * b->write_lock before clearing BTREE_NODE_dirty anymore.
807 */
808 if (btree_node_dirty(b)) {
809 btree_complete_write(b, btree_current_write(b));
810 clear_bit(BTREE_NODE_dirty, &b->flags);
811 }
812 mca_data_free(b);
813 }
814
815 while (!list_empty(&c->btree_cache_freed)) {
816 b = list_first_entry(&c->btree_cache_freed,
817 struct btree, list);
818 list_del(&b->list);
819 cancel_delayed_work_sync(&b->work);
820 kfree(b);
821 }
822
823 mutex_unlock(&c->bucket_lock);
824}
825
826int bch_btree_cache_alloc(struct cache_set *c)
827{
828 unsigned int i;
829
830 for (i = 0; i < mca_reserve(c); i++)
831 if (!mca_bucket_alloc(c, &ZERO_KEY, GFP_KERNEL))
832 return -ENOMEM;
833
834 list_splice_init(&c->btree_cache,
835 &c->btree_cache_freeable);
836
837#ifdef CONFIG_BCACHE_DEBUG
838 mutex_init(&c->verify_lock);
839
840 c->verify_ondisk = (void *)
841 __get_free_pages(GFP_KERNEL, ilog2(bucket_pages(c)));
842
843 c->verify_data = mca_bucket_alloc(c, &ZERO_KEY, GFP_KERNEL);
844
845 if (c->verify_data &&
846 c->verify_data->keys.set->data)
847 list_del_init(&c->verify_data->list);
848 else
849 c->verify_data = NULL;
850#endif
851
852 c->shrink.count_objects = bch_mca_count;
853 c->shrink.scan_objects = bch_mca_scan;
854 c->shrink.seeks = 4;
855 c->shrink.batch = c->btree_pages * 2;
856
857 if (register_shrinker(&c->shrink))
858 pr_warn("bcache: %s: could not register shrinker",
859 __func__);
860
861 return 0;
862}
863
864/* Btree in memory cache - hash table */
865
866static struct hlist_head *mca_hash(struct cache_set *c, struct bkey *k)
867{
868 return &c->bucket_hash[hash_32(PTR_HASH(c, k), BUCKET_HASH_BITS)];
869}
870
871static struct btree *mca_find(struct cache_set *c, struct bkey *k)
872{
873 struct btree *b;
874
875 rcu_read_lock();
876 hlist_for_each_entry_rcu(b, mca_hash(c, k), hash)
877 if (PTR_HASH(c, &b->key) == PTR_HASH(c, k))
878 goto out;
879 b = NULL;
880out:
881 rcu_read_unlock();
882 return b;
883}
884
885static int mca_cannibalize_lock(struct cache_set *c, struct btree_op *op)
886{
887 struct task_struct *old;
888
889 old = cmpxchg(&c->btree_cache_alloc_lock, NULL, current);
890 if (old && old != current) {
891 if (op)
892 prepare_to_wait(&c->btree_cache_wait, &op->wait,
893 TASK_UNINTERRUPTIBLE);
894 return -EINTR;
895 }
896
897 return 0;
898}
899
900static struct btree *mca_cannibalize(struct cache_set *c, struct btree_op *op,
901 struct bkey *k)
902{
903 struct btree *b;
904
905 trace_bcache_btree_cache_cannibalize(c);
906
907 if (mca_cannibalize_lock(c, op))
908 return ERR_PTR(-EINTR);
909
910 list_for_each_entry_reverse(b, &c->btree_cache, list)
911 if (!mca_reap(b, btree_order(k), false))
912 return b;
913
914 list_for_each_entry_reverse(b, &c->btree_cache, list)
915 if (!mca_reap(b, btree_order(k), true))
916 return b;
917
918 WARN(1, "btree cache cannibalize failed\n");
919 return ERR_PTR(-ENOMEM);
920}
921
922/*
923 * We can only have one thread cannibalizing other cached btree nodes at a time,
924 * or we'll deadlock. We use an open coded mutex to ensure that, which a
925 * cannibalize_bucket() will take. This means every time we unlock the root of
926 * the btree, we need to release this lock if we have it held.
927 */
928static void bch_cannibalize_unlock(struct cache_set *c)
929{
930 if (c->btree_cache_alloc_lock == current) {
931 c->btree_cache_alloc_lock = NULL;
932 wake_up(&c->btree_cache_wait);
933 }
934}
935
936static struct btree *mca_alloc(struct cache_set *c, struct btree_op *op,
937 struct bkey *k, int level)
938{
939 struct btree *b;
940
941 BUG_ON(current->bio_list);
942
943 lockdep_assert_held(&c->bucket_lock);
944
945 if (mca_find(c, k))
946 return NULL;
947
948 /* btree_free() doesn't free memory; it sticks the node on the end of
949 * the list. Check if there's any freed nodes there:
950 */
951 list_for_each_entry(b, &c->btree_cache_freeable, list)
952 if (!mca_reap(b, btree_order(k), false))
953 goto out;
954
955 /* We never free struct btree itself, just the memory that holds the on
956 * disk node. Check the freed list before allocating a new one:
957 */
958 list_for_each_entry(b, &c->btree_cache_freed, list)
959 if (!mca_reap(b, 0, false)) {
960 mca_data_alloc(b, k, __GFP_NOWARN|GFP_NOIO);
961 if (!b->keys.set[0].data)
962 goto err;
963 else
964 goto out;
965 }
966
967 b = mca_bucket_alloc(c, k, __GFP_NOWARN|GFP_NOIO);
968 if (!b)
969 goto err;
970
971 BUG_ON(!down_write_trylock(&b->lock));
972 if (!b->keys.set->data)
973 goto err;
974out:
975 BUG_ON(b->io_mutex.count != 1);
976
977 bkey_copy(&b->key, k);
978 list_move(&b->list, &c->btree_cache);
979 hlist_del_init_rcu(&b->hash);
980 hlist_add_head_rcu(&b->hash, mca_hash(c, k));
981
982 lock_set_subclass(&b->lock.dep_map, level + 1, _THIS_IP_);
983 b->parent = (void *) ~0UL;
984 b->flags = 0;
985 b->written = 0;
986 b->level = level;
987
988 if (!b->level)
989 bch_btree_keys_init(&b->keys, &bch_extent_keys_ops,
990 &b->c->expensive_debug_checks);
991 else
992 bch_btree_keys_init(&b->keys, &bch_btree_keys_ops,
993 &b->c->expensive_debug_checks);
994
995 return b;
996err:
997 if (b)
998 rw_unlock(true, b);
999
1000 b = mca_cannibalize(c, op, k);
1001 if (!IS_ERR(b))
1002 goto out;
1003
1004 return b;
1005}
1006
1007/*
1008 * bch_btree_node_get - find a btree node in the cache and lock it, reading it
1009 * in from disk if necessary.
1010 *
1011 * If IO is necessary and running under generic_make_request, returns -EAGAIN.
1012 *
1013 * The btree node will have either a read or a write lock held, depending on
1014 * level and op->lock.
1015 */
1016struct btree *bch_btree_node_get(struct cache_set *c, struct btree_op *op,
1017 struct bkey *k, int level, bool write,
1018 struct btree *parent)
1019{
1020 int i = 0;
1021 struct btree *b;
1022
1023 BUG_ON(level < 0);
1024retry:
1025 b = mca_find(c, k);
1026
1027 if (!b) {
1028 if (current->bio_list)
1029 return ERR_PTR(-EAGAIN);
1030
1031 mutex_lock(&c->bucket_lock);
1032 b = mca_alloc(c, op, k, level);
1033 mutex_unlock(&c->bucket_lock);
1034
1035 if (!b)
1036 goto retry;
1037 if (IS_ERR(b))
1038 return b;
1039
1040 bch_btree_node_read(b);
1041
1042 if (!write)
1043 downgrade_write(&b->lock);
1044 } else {
1045 rw_lock(write, b, level);
1046 if (PTR_HASH(c, &b->key) != PTR_HASH(c, k)) {
1047 rw_unlock(write, b);
1048 goto retry;
1049 }
1050 BUG_ON(b->level != level);
1051 }
1052
1053 if (btree_node_io_error(b)) {
1054 rw_unlock(write, b);
1055 return ERR_PTR(-EIO);
1056 }
1057
1058 BUG_ON(!b->written);
1059
1060 b->parent = parent;
1061 b->accessed = 1;
1062
1063 for (; i <= b->keys.nsets && b->keys.set[i].size; i++) {
1064 prefetch(b->keys.set[i].tree);
1065 prefetch(b->keys.set[i].data);
1066 }
1067
1068 for (; i <= b->keys.nsets; i++)
1069 prefetch(b->keys.set[i].data);
1070
1071 return b;
1072}
1073
1074static void btree_node_prefetch(struct btree *parent, struct bkey *k)
1075{
1076 struct btree *b;
1077
1078 mutex_lock(&parent->c->bucket_lock);
1079 b = mca_alloc(parent->c, NULL, k, parent->level - 1);
1080 mutex_unlock(&parent->c->bucket_lock);
1081
1082 if (!IS_ERR_OR_NULL(b)) {
1083 b->parent = parent;
1084 bch_btree_node_read(b);
1085 rw_unlock(true, b);
1086 }
1087}
1088
1089/* Btree alloc */
1090
1091static void btree_node_free(struct btree *b)
1092{
1093 trace_bcache_btree_node_free(b);
1094
1095 BUG_ON(b == b->c->root);
1096
1097retry:
1098 mutex_lock(&b->write_lock);
1099 /*
1100 * If the btree node is selected and flushing in btree_flush_write(),
1101 * delay and retry until the BTREE_NODE_journal_flush bit cleared,
1102 * then it is safe to free the btree node here. Otherwise this btree
1103 * node will be in race condition.
1104 */
1105 if (btree_node_journal_flush(b)) {
1106 mutex_unlock(&b->write_lock);
1107 pr_debug("bnode %p journal_flush set, retry", b);
1108 udelay(1);
1109 goto retry;
1110 }
1111
1112 if (btree_node_dirty(b)) {
1113 btree_complete_write(b, btree_current_write(b));
1114 clear_bit(BTREE_NODE_dirty, &b->flags);
1115 }
1116
1117 mutex_unlock(&b->write_lock);
1118
1119 cancel_delayed_work(&b->work);
1120
1121 mutex_lock(&b->c->bucket_lock);
1122 bch_bucket_free(b->c, &b->key);
1123 mca_bucket_free(b);
1124 mutex_unlock(&b->c->bucket_lock);
1125}
1126
1127struct btree *__bch_btree_node_alloc(struct cache_set *c, struct btree_op *op,
1128 int level, bool wait,
1129 struct btree *parent)
1130{
1131 BKEY_PADDED(key) k;
1132 struct btree *b = ERR_PTR(-EAGAIN);
1133
1134 mutex_lock(&c->bucket_lock);
1135retry:
1136 if (__bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, 1, wait))
1137 goto err;
1138
1139 bkey_put(c, &k.key);
1140 SET_KEY_SIZE(&k.key, c->btree_pages * PAGE_SECTORS);
1141
1142 b = mca_alloc(c, op, &k.key, level);
1143 if (IS_ERR(b))
1144 goto err_free;
1145
1146 if (!b) {
1147 cache_bug(c,
1148 "Tried to allocate bucket that was in btree cache");
1149 goto retry;
1150 }
1151
1152 b->accessed = 1;
1153 b->parent = parent;
1154 bch_bset_init_next(&b->keys, b->keys.set->data, bset_magic(&b->c->sb));
1155
1156 mutex_unlock(&c->bucket_lock);
1157
1158 trace_bcache_btree_node_alloc(b);
1159 return b;
1160err_free:
1161 bch_bucket_free(c, &k.key);
1162err:
1163 mutex_unlock(&c->bucket_lock);
1164
1165 trace_bcache_btree_node_alloc_fail(c);
1166 return b;
1167}
1168
1169static struct btree *bch_btree_node_alloc(struct cache_set *c,
1170 struct btree_op *op, int level,
1171 struct btree *parent)
1172{
1173 return __bch_btree_node_alloc(c, op, level, op != NULL, parent);
1174}
1175
1176static struct btree *btree_node_alloc_replacement(struct btree *b,
1177 struct btree_op *op)
1178{
1179 struct btree *n = bch_btree_node_alloc(b->c, op, b->level, b->parent);
1180
1181 if (!IS_ERR_OR_NULL(n)) {
1182 mutex_lock(&n->write_lock);
1183 bch_btree_sort_into(&b->keys, &n->keys, &b->c->sort);
1184 bkey_copy_key(&n->key, &b->key);
1185 mutex_unlock(&n->write_lock);
1186 }
1187
1188 return n;
1189}
1190
1191static void make_btree_freeing_key(struct btree *b, struct bkey *k)
1192{
1193 unsigned int i;
1194
1195 mutex_lock(&b->c->bucket_lock);
1196
1197 atomic_inc(&b->c->prio_blocked);
1198
1199 bkey_copy(k, &b->key);
1200 bkey_copy_key(k, &ZERO_KEY);
1201
1202 for (i = 0; i < KEY_PTRS(k); i++)
1203 SET_PTR_GEN(k, i,
1204 bch_inc_gen(PTR_CACHE(b->c, &b->key, i),
1205 PTR_BUCKET(b->c, &b->key, i)));
1206
1207 mutex_unlock(&b->c->bucket_lock);
1208}
1209
1210static int btree_check_reserve(struct btree *b, struct btree_op *op)
1211{
1212 struct cache_set *c = b->c;
1213 struct cache *ca;
1214 unsigned int i, reserve = (c->root->level - b->level) * 2 + 1;
1215
1216 mutex_lock(&c->bucket_lock);
1217
1218 for_each_cache(ca, c, i)
1219 if (fifo_used(&ca->free[RESERVE_BTREE]) < reserve) {
1220 if (op)
1221 prepare_to_wait(&c->btree_cache_wait, &op->wait,
1222 TASK_UNINTERRUPTIBLE);
1223 mutex_unlock(&c->bucket_lock);
1224 return -EINTR;
1225 }
1226
1227 mutex_unlock(&c->bucket_lock);
1228
1229 return mca_cannibalize_lock(b->c, op);
1230}
1231
1232/* Garbage collection */
1233
1234static uint8_t __bch_btree_mark_key(struct cache_set *c, int level,
1235 struct bkey *k)
1236{
1237 uint8_t stale = 0;
1238 unsigned int i;
1239 struct bucket *g;
1240
1241 /*
1242 * ptr_invalid() can't return true for the keys that mark btree nodes as
1243 * freed, but since ptr_bad() returns true we'll never actually use them
1244 * for anything and thus we don't want mark their pointers here
1245 */
1246 if (!bkey_cmp(k, &ZERO_KEY))
1247 return stale;
1248
1249 for (i = 0; i < KEY_PTRS(k); i++) {
1250 if (!ptr_available(c, k, i))
1251 continue;
1252
1253 g = PTR_BUCKET(c, k, i);
1254
1255 if (gen_after(g->last_gc, PTR_GEN(k, i)))
1256 g->last_gc = PTR_GEN(k, i);
1257
1258 if (ptr_stale(c, k, i)) {
1259 stale = max(stale, ptr_stale(c, k, i));
1260 continue;
1261 }
1262
1263 cache_bug_on(GC_MARK(g) &&
1264 (GC_MARK(g) == GC_MARK_METADATA) != (level != 0),
1265 c, "inconsistent ptrs: mark = %llu, level = %i",
1266 GC_MARK(g), level);
1267
1268 if (level)
1269 SET_GC_MARK(g, GC_MARK_METADATA);
1270 else if (KEY_DIRTY(k))
1271 SET_GC_MARK(g, GC_MARK_DIRTY);
1272 else if (!GC_MARK(g))
1273 SET_GC_MARK(g, GC_MARK_RECLAIMABLE);
1274
1275 /* guard against overflow */
1276 SET_GC_SECTORS_USED(g, min_t(unsigned int,
1277 GC_SECTORS_USED(g) + KEY_SIZE(k),
1278 MAX_GC_SECTORS_USED));
1279
1280 BUG_ON(!GC_SECTORS_USED(g));
1281 }
1282
1283 return stale;
1284}
1285
1286#define btree_mark_key(b, k) __bch_btree_mark_key(b->c, b->level, k)
1287
1288void bch_initial_mark_key(struct cache_set *c, int level, struct bkey *k)
1289{
1290 unsigned int i;
1291
1292 for (i = 0; i < KEY_PTRS(k); i++)
1293 if (ptr_available(c, k, i) &&
1294 !ptr_stale(c, k, i)) {
1295 struct bucket *b = PTR_BUCKET(c, k, i);
1296
1297 b->gen = PTR_GEN(k, i);
1298
1299 if (level && bkey_cmp(k, &ZERO_KEY))
1300 b->prio = BTREE_PRIO;
1301 else if (!level && b->prio == BTREE_PRIO)
1302 b->prio = INITIAL_PRIO;
1303 }
1304
1305 __bch_btree_mark_key(c, level, k);
1306}
1307
1308void bch_update_bucket_in_use(struct cache_set *c, struct gc_stat *stats)
1309{
1310 stats->in_use = (c->nbuckets - c->avail_nbuckets) * 100 / c->nbuckets;
1311}
1312
1313static bool btree_gc_mark_node(struct btree *b, struct gc_stat *gc)
1314{
1315 uint8_t stale = 0;
1316 unsigned int keys = 0, good_keys = 0;
1317 struct bkey *k;
1318 struct btree_iter iter;
1319 struct bset_tree *t;
1320
1321 gc->nodes++;
1322
1323 for_each_key_filter(&b->keys, k, &iter, bch_ptr_invalid) {
1324 stale = max(stale, btree_mark_key(b, k));
1325 keys++;
1326
1327 if (bch_ptr_bad(&b->keys, k))
1328 continue;
1329
1330 gc->key_bytes += bkey_u64s(k);
1331 gc->nkeys++;
1332 good_keys++;
1333
1334 gc->data += KEY_SIZE(k);
1335 }
1336
1337 for (t = b->keys.set; t <= &b->keys.set[b->keys.nsets]; t++)
1338 btree_bug_on(t->size &&
1339 bset_written(&b->keys, t) &&
1340 bkey_cmp(&b->key, &t->end) < 0,
1341 b, "found short btree key in gc");
1342
1343 if (b->c->gc_always_rewrite)
1344 return true;
1345
1346 if (stale > 10)
1347 return true;
1348
1349 if ((keys - good_keys) * 2 > keys)
1350 return true;
1351
1352 return false;
1353}
1354
1355#define GC_MERGE_NODES 4U
1356
1357struct gc_merge_info {
1358 struct btree *b;
1359 unsigned int keys;
1360};
1361
1362static int bch_btree_insert_node(struct btree *b, struct btree_op *op,
1363 struct keylist *insert_keys,
1364 atomic_t *journal_ref,
1365 struct bkey *replace_key);
1366
1367static int btree_gc_coalesce(struct btree *b, struct btree_op *op,
1368 struct gc_stat *gc, struct gc_merge_info *r)
1369{
1370 unsigned int i, nodes = 0, keys = 0, blocks;
1371 struct btree *new_nodes[GC_MERGE_NODES];
1372 struct keylist keylist;
1373 struct closure cl;
1374 struct bkey *k;
1375
1376 bch_keylist_init(&keylist);
1377
1378 if (btree_check_reserve(b, NULL))
1379 return 0;
1380
1381 memset(new_nodes, 0, sizeof(new_nodes));
1382 closure_init_stack(&cl);
1383
1384 while (nodes < GC_MERGE_NODES && !IS_ERR_OR_NULL(r[nodes].b))
1385 keys += r[nodes++].keys;
1386
1387 blocks = btree_default_blocks(b->c) * 2 / 3;
1388
1389 if (nodes < 2 ||
1390 __set_blocks(b->keys.set[0].data, keys,
1391 block_bytes(b->c)) > blocks * (nodes - 1))
1392 return 0;
1393
1394 for (i = 0; i < nodes; i++) {
1395 new_nodes[i] = btree_node_alloc_replacement(r[i].b, NULL);
1396 if (IS_ERR_OR_NULL(new_nodes[i]))
1397 goto out_nocoalesce;
1398 }
1399
1400 /*
1401 * We have to check the reserve here, after we've allocated our new
1402 * nodes, to make sure the insert below will succeed - we also check
1403 * before as an optimization to potentially avoid a bunch of expensive
1404 * allocs/sorts
1405 */
1406 if (btree_check_reserve(b, NULL))
1407 goto out_nocoalesce;
1408
1409 for (i = 0; i < nodes; i++)
1410 mutex_lock(&new_nodes[i]->write_lock);
1411
1412 for (i = nodes - 1; i > 0; --i) {
1413 struct bset *n1 = btree_bset_first(new_nodes[i]);
1414 struct bset *n2 = btree_bset_first(new_nodes[i - 1]);
1415 struct bkey *k, *last = NULL;
1416
1417 keys = 0;
1418
1419 if (i > 1) {
1420 for (k = n2->start;
1421 k < bset_bkey_last(n2);
1422 k = bkey_next(k)) {
1423 if (__set_blocks(n1, n1->keys + keys +
1424 bkey_u64s(k),
1425 block_bytes(b->c)) > blocks)
1426 break;
1427
1428 last = k;
1429 keys += bkey_u64s(k);
1430 }
1431 } else {
1432 /*
1433 * Last node we're not getting rid of - we're getting
1434 * rid of the node at r[0]. Have to try and fit all of
1435 * the remaining keys into this node; we can't ensure
1436 * they will always fit due to rounding and variable
1437 * length keys (shouldn't be possible in practice,
1438 * though)
1439 */
1440 if (__set_blocks(n1, n1->keys + n2->keys,
1441 block_bytes(b->c)) >
1442 btree_blocks(new_nodes[i]))
1443 goto out_nocoalesce;
1444
1445 keys = n2->keys;
1446 /* Take the key of the node we're getting rid of */
1447 last = &r->b->key;
1448 }
1449
1450 BUG_ON(__set_blocks(n1, n1->keys + keys, block_bytes(b->c)) >
1451 btree_blocks(new_nodes[i]));
1452
1453 if (last)
1454 bkey_copy_key(&new_nodes[i]->key, last);
1455
1456 memcpy(bset_bkey_last(n1),
1457 n2->start,
1458 (void *) bset_bkey_idx(n2, keys) - (void *) n2->start);
1459
1460 n1->keys += keys;
1461 r[i].keys = n1->keys;
1462
1463 memmove(n2->start,
1464 bset_bkey_idx(n2, keys),
1465 (void *) bset_bkey_last(n2) -
1466 (void *) bset_bkey_idx(n2, keys));
1467
1468 n2->keys -= keys;
1469
1470 if (__bch_keylist_realloc(&keylist,
1471 bkey_u64s(&new_nodes[i]->key)))
1472 goto out_nocoalesce;
1473
1474 bch_btree_node_write(new_nodes[i], &cl);
1475 bch_keylist_add(&keylist, &new_nodes[i]->key);
1476 }
1477
1478 for (i = 0; i < nodes; i++)
1479 mutex_unlock(&new_nodes[i]->write_lock);
1480
1481 closure_sync(&cl);
1482
1483 /* We emptied out this node */
1484 BUG_ON(btree_bset_first(new_nodes[0])->keys);
1485 btree_node_free(new_nodes[0]);
1486 rw_unlock(true, new_nodes[0]);
1487 new_nodes[0] = NULL;
1488
1489 for (i = 0; i < nodes; i++) {
1490 if (__bch_keylist_realloc(&keylist, bkey_u64s(&r[i].b->key)))
1491 goto out_nocoalesce;
1492
1493 make_btree_freeing_key(r[i].b, keylist.top);
1494 bch_keylist_push(&keylist);
1495 }
1496
1497 bch_btree_insert_node(b, op, &keylist, NULL, NULL);
1498 BUG_ON(!bch_keylist_empty(&keylist));
1499
1500 for (i = 0; i < nodes; i++) {
1501 btree_node_free(r[i].b);
1502 rw_unlock(true, r[i].b);
1503
1504 r[i].b = new_nodes[i];
1505 }
1506
1507 memmove(r, r + 1, sizeof(r[0]) * (nodes - 1));
1508 r[nodes - 1].b = ERR_PTR(-EINTR);
1509
1510 trace_bcache_btree_gc_coalesce(nodes);
1511 gc->nodes--;
1512
1513 bch_keylist_free(&keylist);
1514
1515 /* Invalidated our iterator */
1516 return -EINTR;
1517
1518out_nocoalesce:
1519 closure_sync(&cl);
1520
1521 while ((k = bch_keylist_pop(&keylist)))
1522 if (!bkey_cmp(k, &ZERO_KEY))
1523 atomic_dec(&b->c->prio_blocked);
1524 bch_keylist_free(&keylist);
1525
1526 for (i = 0; i < nodes; i++)
1527 if (!IS_ERR_OR_NULL(new_nodes[i])) {
1528 btree_node_free(new_nodes[i]);
1529 rw_unlock(true, new_nodes[i]);
1530 }
1531 return 0;
1532}
1533
1534static int btree_gc_rewrite_node(struct btree *b, struct btree_op *op,
1535 struct btree *replace)
1536{
1537 struct keylist keys;
1538 struct btree *n;
1539
1540 if (btree_check_reserve(b, NULL))
1541 return 0;
1542
1543 n = btree_node_alloc_replacement(replace, NULL);
1544
1545 /* recheck reserve after allocating replacement node */
1546 if (btree_check_reserve(b, NULL)) {
1547 btree_node_free(n);
1548 rw_unlock(true, n);
1549 return 0;
1550 }
1551
1552 bch_btree_node_write_sync(n);
1553
1554 bch_keylist_init(&keys);
1555 bch_keylist_add(&keys, &n->key);
1556
1557 make_btree_freeing_key(replace, keys.top);
1558 bch_keylist_push(&keys);
1559
1560 bch_btree_insert_node(b, op, &keys, NULL, NULL);
1561 BUG_ON(!bch_keylist_empty(&keys));
1562
1563 btree_node_free(replace);
1564 rw_unlock(true, n);
1565
1566 /* Invalidated our iterator */
1567 return -EINTR;
1568}
1569
1570static unsigned int btree_gc_count_keys(struct btree *b)
1571{
1572 struct bkey *k;
1573 struct btree_iter iter;
1574 unsigned int ret = 0;
1575
1576 for_each_key_filter(&b->keys, k, &iter, bch_ptr_bad)
1577 ret += bkey_u64s(k);
1578
1579 return ret;
1580}
1581
1582static size_t btree_gc_min_nodes(struct cache_set *c)
1583{
1584 size_t min_nodes;
1585
1586 /*
1587 * Since incremental GC would stop 100ms when front
1588 * side I/O comes, so when there are many btree nodes,
1589 * if GC only processes constant (100) nodes each time,
1590 * GC would last a long time, and the front side I/Os
1591 * would run out of the buckets (since no new bucket
1592 * can be allocated during GC), and be blocked again.
1593 * So GC should not process constant nodes, but varied
1594 * nodes according to the number of btree nodes, which
1595 * realized by dividing GC into constant(100) times,
1596 * so when there are many btree nodes, GC can process
1597 * more nodes each time, otherwise, GC will process less
1598 * nodes each time (but no less than MIN_GC_NODES)
1599 */
1600 min_nodes = c->gc_stats.nodes / MAX_GC_TIMES;
1601 if (min_nodes < MIN_GC_NODES)
1602 min_nodes = MIN_GC_NODES;
1603
1604 return min_nodes;
1605}
1606
1607
1608static int btree_gc_recurse(struct btree *b, struct btree_op *op,
1609 struct closure *writes, struct gc_stat *gc)
1610{
1611 int ret = 0;
1612 bool should_rewrite;
1613 struct bkey *k;
1614 struct btree_iter iter;
1615 struct gc_merge_info r[GC_MERGE_NODES];
1616 struct gc_merge_info *i, *last = r + ARRAY_SIZE(r) - 1;
1617
1618 bch_btree_iter_init(&b->keys, &iter, &b->c->gc_done);
1619
1620 for (i = r; i < r + ARRAY_SIZE(r); i++)
1621 i->b = ERR_PTR(-EINTR);
1622
1623 while (1) {
1624 k = bch_btree_iter_next_filter(&iter, &b->keys, bch_ptr_bad);
1625 if (k) {
1626 r->b = bch_btree_node_get(b->c, op, k, b->level - 1,
1627 true, b);
1628 if (IS_ERR(r->b)) {
1629 ret = PTR_ERR(r->b);
1630 break;
1631 }
1632
1633 r->keys = btree_gc_count_keys(r->b);
1634
1635 ret = btree_gc_coalesce(b, op, gc, r);
1636 if (ret)
1637 break;
1638 }
1639
1640 if (!last->b)
1641 break;
1642
1643 if (!IS_ERR(last->b)) {
1644 should_rewrite = btree_gc_mark_node(last->b, gc);
1645 if (should_rewrite) {
1646 ret = btree_gc_rewrite_node(b, op, last->b);
1647 if (ret)
1648 break;
1649 }
1650
1651 if (last->b->level) {
1652 ret = btree_gc_recurse(last->b, op, writes, gc);
1653 if (ret)
1654 break;
1655 }
1656
1657 bkey_copy_key(&b->c->gc_done, &last->b->key);
1658
1659 /*
1660 * Must flush leaf nodes before gc ends, since replace
1661 * operations aren't journalled
1662 */
1663 mutex_lock(&last->b->write_lock);
1664 if (btree_node_dirty(last->b))
1665 bch_btree_node_write(last->b, writes);
1666 mutex_unlock(&last->b->write_lock);
1667 rw_unlock(true, last->b);
1668 }
1669
1670 memmove(r + 1, r, sizeof(r[0]) * (GC_MERGE_NODES - 1));
1671 r->b = NULL;
1672
1673 if (atomic_read(&b->c->search_inflight) &&
1674 gc->nodes >= gc->nodes_pre + btree_gc_min_nodes(b->c)) {
1675 gc->nodes_pre = gc->nodes;
1676 ret = -EAGAIN;
1677 break;
1678 }
1679
1680 if (need_resched()) {
1681 ret = -EAGAIN;
1682 break;
1683 }
1684 }
1685
1686 for (i = r; i < r + ARRAY_SIZE(r); i++)
1687 if (!IS_ERR_OR_NULL(i->b)) {
1688 mutex_lock(&i->b->write_lock);
1689 if (btree_node_dirty(i->b))
1690 bch_btree_node_write(i->b, writes);
1691 mutex_unlock(&i->b->write_lock);
1692 rw_unlock(true, i->b);
1693 }
1694
1695 return ret;
1696}
1697
1698static int bch_btree_gc_root(struct btree *b, struct btree_op *op,
1699 struct closure *writes, struct gc_stat *gc)
1700{
1701 struct btree *n = NULL;
1702 int ret = 0;
1703 bool should_rewrite;
1704
1705 should_rewrite = btree_gc_mark_node(b, gc);
1706 if (should_rewrite) {
1707 n = btree_node_alloc_replacement(b, NULL);
1708
1709 if (!IS_ERR_OR_NULL(n)) {
1710 bch_btree_node_write_sync(n);
1711
1712 bch_btree_set_root(n);
1713 btree_node_free(b);
1714 rw_unlock(true, n);
1715
1716 return -EINTR;
1717 }
1718 }
1719
1720 __bch_btree_mark_key(b->c, b->level + 1, &b->key);
1721
1722 if (b->level) {
1723 ret = btree_gc_recurse(b, op, writes, gc);
1724 if (ret)
1725 return ret;
1726 }
1727
1728 bkey_copy_key(&b->c->gc_done, &b->key);
1729
1730 return ret;
1731}
1732
1733static void btree_gc_start(struct cache_set *c)
1734{
1735 struct cache *ca;
1736 struct bucket *b;
1737 unsigned int i;
1738
1739 if (!c->gc_mark_valid)
1740 return;
1741
1742 mutex_lock(&c->bucket_lock);
1743
1744 c->gc_mark_valid = 0;
1745 c->gc_done = ZERO_KEY;
1746
1747 for_each_cache(ca, c, i)
1748 for_each_bucket(b, ca) {
1749 b->last_gc = b->gen;
1750 if (!atomic_read(&b->pin)) {
1751 SET_GC_MARK(b, 0);
1752 SET_GC_SECTORS_USED(b, 0);
1753 }
1754 }
1755
1756 mutex_unlock(&c->bucket_lock);
1757}
1758
1759static void bch_btree_gc_finish(struct cache_set *c)
1760{
1761 struct bucket *b;
1762 struct cache *ca;
1763 unsigned int i;
1764
1765 mutex_lock(&c->bucket_lock);
1766
1767 set_gc_sectors(c);
1768 c->gc_mark_valid = 1;
1769 c->need_gc = 0;
1770
1771 for (i = 0; i < KEY_PTRS(&c->uuid_bucket); i++)
1772 SET_GC_MARK(PTR_BUCKET(c, &c->uuid_bucket, i),
1773 GC_MARK_METADATA);
1774
1775 /* don't reclaim buckets to which writeback keys point */
1776 rcu_read_lock();
1777 for (i = 0; i < c->devices_max_used; i++) {
1778 struct bcache_device *d = c->devices[i];
1779 struct cached_dev *dc;
1780 struct keybuf_key *w, *n;
1781 unsigned int j;
1782
1783 if (!d || UUID_FLASH_ONLY(&c->uuids[i]))
1784 continue;
1785 dc = container_of(d, struct cached_dev, disk);
1786
1787 spin_lock(&dc->writeback_keys.lock);
1788 rbtree_postorder_for_each_entry_safe(w, n,
1789 &dc->writeback_keys.keys, node)
1790 for (j = 0; j < KEY_PTRS(&w->key); j++)
1791 SET_GC_MARK(PTR_BUCKET(c, &w->key, j),
1792 GC_MARK_DIRTY);
1793 spin_unlock(&dc->writeback_keys.lock);
1794 }
1795 rcu_read_unlock();
1796
1797 c->avail_nbuckets = 0;
1798 for_each_cache(ca, c, i) {
1799 uint64_t *i;
1800
1801 ca->invalidate_needs_gc = 0;
1802
1803 for (i = ca->sb.d; i < ca->sb.d + ca->sb.keys; i++)
1804 SET_GC_MARK(ca->buckets + *i, GC_MARK_METADATA);
1805
1806 for (i = ca->prio_buckets;
1807 i < ca->prio_buckets + prio_buckets(ca) * 2; i++)
1808 SET_GC_MARK(ca->buckets + *i, GC_MARK_METADATA);
1809
1810 for_each_bucket(b, ca) {
1811 c->need_gc = max(c->need_gc, bucket_gc_gen(b));
1812
1813 if (atomic_read(&b->pin))
1814 continue;
1815
1816 BUG_ON(!GC_MARK(b) && GC_SECTORS_USED(b));
1817
1818 if (!GC_MARK(b) || GC_MARK(b) == GC_MARK_RECLAIMABLE)
1819 c->avail_nbuckets++;
1820 }
1821 }
1822
1823 mutex_unlock(&c->bucket_lock);
1824}
1825
1826static void bch_btree_gc(struct cache_set *c)
1827{
1828 int ret;
1829 struct gc_stat stats;
1830 struct closure writes;
1831 struct btree_op op;
1832 uint64_t start_time = local_clock();
1833
1834 trace_bcache_gc_start(c);
1835
1836 memset(&stats, 0, sizeof(struct gc_stat));
1837 closure_init_stack(&writes);
1838 bch_btree_op_init(&op, SHRT_MAX);
1839
1840 btree_gc_start(c);
1841
1842 /* if CACHE_SET_IO_DISABLE set, gc thread should stop too */
1843 do {
1844 ret = btree_root(gc_root, c, &op, &writes, &stats);
1845 closure_sync(&writes);
1846 cond_resched();
1847
1848 if (ret == -EAGAIN)
1849 schedule_timeout_interruptible(msecs_to_jiffies
1850 (GC_SLEEP_MS));
1851 else if (ret)
1852 pr_warn("gc failed!");
1853 } while (ret && !test_bit(CACHE_SET_IO_DISABLE, &c->flags));
1854
1855 bch_btree_gc_finish(c);
1856 wake_up_allocators(c);
1857
1858 bch_time_stats_update(&c->btree_gc_time, start_time);
1859
1860 stats.key_bytes *= sizeof(uint64_t);
1861 stats.data <<= 9;
1862 bch_update_bucket_in_use(c, &stats);
1863 memcpy(&c->gc_stats, &stats, sizeof(struct gc_stat));
1864
1865 trace_bcache_gc_end(c);
1866
1867 bch_moving_gc(c);
1868}
1869
1870static bool gc_should_run(struct cache_set *c)
1871{
1872 struct cache *ca;
1873 unsigned int i;
1874
1875 for_each_cache(ca, c, i)
1876 if (ca->invalidate_needs_gc)
1877 return true;
1878
1879 if (atomic_read(&c->sectors_to_gc) < 0)
1880 return true;
1881
1882 return false;
1883}
1884
1885static int bch_gc_thread(void *arg)
1886{
1887 struct cache_set *c = arg;
1888
1889 while (1) {
1890 wait_event_interruptible(c->gc_wait,
1891 kthread_should_stop() ||
1892 test_bit(CACHE_SET_IO_DISABLE, &c->flags) ||
1893 gc_should_run(c));
1894
1895 if (kthread_should_stop() ||
1896 test_bit(CACHE_SET_IO_DISABLE, &c->flags))
1897 break;
1898
1899 set_gc_sectors(c);
1900 bch_btree_gc(c);
1901 }
1902
1903 wait_for_kthread_stop();
1904 return 0;
1905}
1906
1907int bch_gc_thread_start(struct cache_set *c)
1908{
1909 c->gc_thread = kthread_run(bch_gc_thread, c, "bcache_gc");
1910 return PTR_ERR_OR_ZERO(c->gc_thread);
1911}
1912
1913/* Initial partial gc */
1914
1915static int bch_btree_check_recurse(struct btree *b, struct btree_op *op)
1916{
1917 int ret = 0;
1918 struct bkey *k, *p = NULL;
1919 struct btree_iter iter;
1920
1921 for_each_key_filter(&b->keys, k, &iter, bch_ptr_invalid)
1922 bch_initial_mark_key(b->c, b->level, k);
1923
1924 bch_initial_mark_key(b->c, b->level + 1, &b->key);
1925
1926 if (b->level) {
1927 bch_btree_iter_init(&b->keys, &iter, NULL);
1928
1929 do {
1930 k = bch_btree_iter_next_filter(&iter, &b->keys,
1931 bch_ptr_bad);
1932 if (k) {
1933 btree_node_prefetch(b, k);
1934 /*
1935 * initiallize c->gc_stats.nodes
1936 * for incremental GC
1937 */
1938 b->c->gc_stats.nodes++;
1939 }
1940
1941 if (p)
1942 ret = btree(check_recurse, p, b, op);
1943
1944 p = k;
1945 } while (p && !ret);
1946 }
1947
1948 return ret;
1949}
1950
1951int bch_btree_check(struct cache_set *c)
1952{
1953 struct btree_op op;
1954
1955 bch_btree_op_init(&op, SHRT_MAX);
1956
1957 return btree_root(check_recurse, c, &op);
1958}
1959
1960void bch_initial_gc_finish(struct cache_set *c)
1961{
1962 struct cache *ca;
1963 struct bucket *b;
1964 unsigned int i;
1965
1966 bch_btree_gc_finish(c);
1967
1968 mutex_lock(&c->bucket_lock);
1969
1970 /*
1971 * We need to put some unused buckets directly on the prio freelist in
1972 * order to get the allocator thread started - it needs freed buckets in
1973 * order to rewrite the prios and gens, and it needs to rewrite prios
1974 * and gens in order to free buckets.
1975 *
1976 * This is only safe for buckets that have no live data in them, which
1977 * there should always be some of.
1978 */
1979 for_each_cache(ca, c, i) {
1980 for_each_bucket(b, ca) {
1981 if (fifo_full(&ca->free[RESERVE_PRIO]) &&
1982 fifo_full(&ca->free[RESERVE_BTREE]))
1983 break;
1984
1985 if (bch_can_invalidate_bucket(ca, b) &&
1986 !GC_MARK(b)) {
1987 __bch_invalidate_one_bucket(ca, b);
1988 if (!fifo_push(&ca->free[RESERVE_PRIO],
1989 b - ca->buckets))
1990 fifo_push(&ca->free[RESERVE_BTREE],
1991 b - ca->buckets);
1992 }
1993 }
1994 }
1995
1996 mutex_unlock(&c->bucket_lock);
1997}
1998
1999/* Btree insertion */
2000
2001static bool btree_insert_key(struct btree *b, struct bkey *k,
2002 struct bkey *replace_key)
2003{
2004 unsigned int status;
2005
2006 BUG_ON(bkey_cmp(k, &b->key) > 0);
2007
2008 status = bch_btree_insert_key(&b->keys, k, replace_key);
2009 if (status != BTREE_INSERT_STATUS_NO_INSERT) {
2010 bch_check_keys(&b->keys, "%u for %s", status,
2011 replace_key ? "replace" : "insert");
2012
2013 trace_bcache_btree_insert_key(b, k, replace_key != NULL,
2014 status);
2015 return true;
2016 } else
2017 return false;
2018}
2019
2020static size_t insert_u64s_remaining(struct btree *b)
2021{
2022 long ret = bch_btree_keys_u64s_remaining(&b->keys);
2023
2024 /*
2025 * Might land in the middle of an existing extent and have to split it
2026 */
2027 if (b->keys.ops->is_extents)
2028 ret -= KEY_MAX_U64S;
2029
2030 return max(ret, 0L);
2031}
2032
2033static bool bch_btree_insert_keys(struct btree *b, struct btree_op *op,
2034 struct keylist *insert_keys,
2035 struct bkey *replace_key)
2036{
2037 bool ret = false;
2038 int oldsize = bch_count_data(&b->keys);
2039
2040 while (!bch_keylist_empty(insert_keys)) {
2041 struct bkey *k = insert_keys->keys;
2042
2043 if (bkey_u64s(k) > insert_u64s_remaining(b))
2044 break;
2045
2046 if (bkey_cmp(k, &b->key) <= 0) {
2047 if (!b->level)
2048 bkey_put(b->c, k);
2049
2050 ret |= btree_insert_key(b, k, replace_key);
2051 bch_keylist_pop_front(insert_keys);
2052 } else if (bkey_cmp(&START_KEY(k), &b->key) < 0) {
2053 BKEY_PADDED(key) temp;
2054 bkey_copy(&temp.key, insert_keys->keys);
2055
2056 bch_cut_back(&b->key, &temp.key);
2057 bch_cut_front(&b->key, insert_keys->keys);
2058
2059 ret |= btree_insert_key(b, &temp.key, replace_key);
2060 break;
2061 } else {
2062 break;
2063 }
2064 }
2065
2066 if (!ret)
2067 op->insert_collision = true;
2068
2069 BUG_ON(!bch_keylist_empty(insert_keys) && b->level);
2070
2071 BUG_ON(bch_count_data(&b->keys) < oldsize);
2072 return ret;
2073}
2074
2075static int btree_split(struct btree *b, struct btree_op *op,
2076 struct keylist *insert_keys,
2077 struct bkey *replace_key)
2078{
2079 bool split;
2080 struct btree *n1, *n2 = NULL, *n3 = NULL;
2081 uint64_t start_time = local_clock();
2082 struct closure cl;
2083 struct keylist parent_keys;
2084
2085 closure_init_stack(&cl);
2086 bch_keylist_init(&parent_keys);
2087
2088 if (btree_check_reserve(b, op)) {
2089 if (!b->level)
2090 return -EINTR;
2091 else
2092 WARN(1, "insufficient reserve for split\n");
2093 }
2094
2095 n1 = btree_node_alloc_replacement(b, op);
2096 if (IS_ERR(n1))
2097 goto err;
2098
2099 split = set_blocks(btree_bset_first(n1),
2100 block_bytes(n1->c)) > (btree_blocks(b) * 4) / 5;
2101
2102 if (split) {
2103 unsigned int keys = 0;
2104
2105 trace_bcache_btree_node_split(b, btree_bset_first(n1)->keys);
2106
2107 n2 = bch_btree_node_alloc(b->c, op, b->level, b->parent);
2108 if (IS_ERR(n2))
2109 goto err_free1;
2110
2111 if (!b->parent) {
2112 n3 = bch_btree_node_alloc(b->c, op, b->level + 1, NULL);
2113 if (IS_ERR(n3))
2114 goto err_free2;
2115 }
2116
2117 mutex_lock(&n1->write_lock);
2118 mutex_lock(&n2->write_lock);
2119
2120 bch_btree_insert_keys(n1, op, insert_keys, replace_key);
2121
2122 /*
2123 * Has to be a linear search because we don't have an auxiliary
2124 * search tree yet
2125 */
2126
2127 while (keys < (btree_bset_first(n1)->keys * 3) / 5)
2128 keys += bkey_u64s(bset_bkey_idx(btree_bset_first(n1),
2129 keys));
2130
2131 bkey_copy_key(&n1->key,
2132 bset_bkey_idx(btree_bset_first(n1), keys));
2133 keys += bkey_u64s(bset_bkey_idx(btree_bset_first(n1), keys));
2134
2135 btree_bset_first(n2)->keys = btree_bset_first(n1)->keys - keys;
2136 btree_bset_first(n1)->keys = keys;
2137
2138 memcpy(btree_bset_first(n2)->start,
2139 bset_bkey_last(btree_bset_first(n1)),
2140 btree_bset_first(n2)->keys * sizeof(uint64_t));
2141
2142 bkey_copy_key(&n2->key, &b->key);
2143
2144 bch_keylist_add(&parent_keys, &n2->key);
2145 bch_btree_node_write(n2, &cl);
2146 mutex_unlock(&n2->write_lock);
2147 rw_unlock(true, n2);
2148 } else {
2149 trace_bcache_btree_node_compact(b, btree_bset_first(n1)->keys);
2150
2151 mutex_lock(&n1->write_lock);
2152 bch_btree_insert_keys(n1, op, insert_keys, replace_key);
2153 }
2154
2155 bch_keylist_add(&parent_keys, &n1->key);
2156 bch_btree_node_write(n1, &cl);
2157 mutex_unlock(&n1->write_lock);
2158
2159 if (n3) {
2160 /* Depth increases, make a new root */
2161 mutex_lock(&n3->write_lock);
2162 bkey_copy_key(&n3->key, &MAX_KEY);
2163 bch_btree_insert_keys(n3, op, &parent_keys, NULL);
2164 bch_btree_node_write(n3, &cl);
2165 mutex_unlock(&n3->write_lock);
2166
2167 closure_sync(&cl);
2168 bch_btree_set_root(n3);
2169 rw_unlock(true, n3);
2170 } else if (!b->parent) {
2171 /* Root filled up but didn't need to be split */
2172 closure_sync(&cl);
2173 bch_btree_set_root(n1);
2174 } else {
2175 /* Split a non root node */
2176 closure_sync(&cl);
2177 make_btree_freeing_key(b, parent_keys.top);
2178 bch_keylist_push(&parent_keys);
2179
2180 bch_btree_insert_node(b->parent, op, &parent_keys, NULL, NULL);
2181 BUG_ON(!bch_keylist_empty(&parent_keys));
2182 }
2183
2184 btree_node_free(b);
2185 rw_unlock(true, n1);
2186
2187 bch_time_stats_update(&b->c->btree_split_time, start_time);
2188
2189 return 0;
2190err_free2:
2191 bkey_put(b->c, &n2->key);
2192 btree_node_free(n2);
2193 rw_unlock(true, n2);
2194err_free1:
2195 bkey_put(b->c, &n1->key);
2196 btree_node_free(n1);
2197 rw_unlock(true, n1);
2198err:
2199 WARN(1, "bcache: btree split failed (level %u)", b->level);
2200
2201 if (n3 == ERR_PTR(-EAGAIN) ||
2202 n2 == ERR_PTR(-EAGAIN) ||
2203 n1 == ERR_PTR(-EAGAIN))
2204 return -EAGAIN;
2205
2206 return -ENOMEM;
2207}
2208
2209static int bch_btree_insert_node(struct btree *b, struct btree_op *op,
2210 struct keylist *insert_keys,
2211 atomic_t *journal_ref,
2212 struct bkey *replace_key)
2213{
2214 struct closure cl;
2215
2216 BUG_ON(b->level && replace_key);
2217
2218 closure_init_stack(&cl);
2219
2220 mutex_lock(&b->write_lock);
2221
2222 if (write_block(b) != btree_bset_last(b) &&
2223 b->keys.last_set_unwritten)
2224 bch_btree_init_next(b); /* just wrote a set */
2225
2226 if (bch_keylist_nkeys(insert_keys) > insert_u64s_remaining(b)) {
2227 mutex_unlock(&b->write_lock);
2228 goto split;
2229 }
2230
2231 BUG_ON(write_block(b) != btree_bset_last(b));
2232
2233 if (bch_btree_insert_keys(b, op, insert_keys, replace_key)) {
2234 if (!b->level)
2235 bch_btree_leaf_dirty(b, journal_ref);
2236 else
2237 bch_btree_node_write(b, &cl);
2238 }
2239
2240 mutex_unlock(&b->write_lock);
2241
2242 /* wait for btree node write if necessary, after unlock */
2243 closure_sync(&cl);
2244
2245 return 0;
2246split:
2247 if (current->bio_list) {
2248 op->lock = b->c->root->level + 1;
2249 return -EAGAIN;
2250 } else if (op->lock <= b->c->root->level) {
2251 op->lock = b->c->root->level + 1;
2252 return -EINTR;
2253 } else {
2254 /* Invalidated all iterators */
2255 int ret = btree_split(b, op, insert_keys, replace_key);
2256
2257 if (bch_keylist_empty(insert_keys))
2258 return 0;
2259 else if (!ret)
2260 return -EINTR;
2261 return ret;
2262 }
2263}
2264
2265int bch_btree_insert_check_key(struct btree *b, struct btree_op *op,
2266 struct bkey *check_key)
2267{
2268 int ret = -EINTR;
2269 uint64_t btree_ptr = b->key.ptr[0];
2270 unsigned long seq = b->seq;
2271 struct keylist insert;
2272 bool upgrade = op->lock == -1;
2273
2274 bch_keylist_init(&insert);
2275
2276 if (upgrade) {
2277 rw_unlock(false, b);
2278 rw_lock(true, b, b->level);
2279
2280 if (b->key.ptr[0] != btree_ptr ||
2281 b->seq != seq + 1) {
2282 op->lock = b->level;
2283 goto out;
2284 }
2285 }
2286
2287 SET_KEY_PTRS(check_key, 1);
2288 get_random_bytes(&check_key->ptr[0], sizeof(uint64_t));
2289
2290 SET_PTR_DEV(check_key, 0, PTR_CHECK_DEV);
2291
2292 bch_keylist_add(&insert, check_key);
2293
2294 ret = bch_btree_insert_node(b, op, &insert, NULL, NULL);
2295
2296 BUG_ON(!ret && !bch_keylist_empty(&insert));
2297out:
2298 if (upgrade)
2299 downgrade_write(&b->lock);
2300 return ret;
2301}
2302
2303struct btree_insert_op {
2304 struct btree_op op;
2305 struct keylist *keys;
2306 atomic_t *journal_ref;
2307 struct bkey *replace_key;
2308};
2309
2310static int btree_insert_fn(struct btree_op *b_op, struct btree *b)
2311{
2312 struct btree_insert_op *op = container_of(b_op,
2313 struct btree_insert_op, op);
2314
2315 int ret = bch_btree_insert_node(b, &op->op, op->keys,
2316 op->journal_ref, op->replace_key);
2317 if (ret && !bch_keylist_empty(op->keys))
2318 return ret;
2319 else
2320 return MAP_DONE;
2321}
2322
2323int bch_btree_insert(struct cache_set *c, struct keylist *keys,
2324 atomic_t *journal_ref, struct bkey *replace_key)
2325{
2326 struct btree_insert_op op;
2327 int ret = 0;
2328
2329 BUG_ON(current->bio_list);
2330 BUG_ON(bch_keylist_empty(keys));
2331
2332 bch_btree_op_init(&op.op, 0);
2333 op.keys = keys;
2334 op.journal_ref = journal_ref;
2335 op.replace_key = replace_key;
2336
2337 while (!ret && !bch_keylist_empty(keys)) {
2338 op.op.lock = 0;
2339 ret = bch_btree_map_leaf_nodes(&op.op, c,
2340 &START_KEY(keys->keys),
2341 btree_insert_fn);
2342 }
2343
2344 if (ret) {
2345 struct bkey *k;
2346
2347 pr_err("error %i", ret);
2348
2349 while ((k = bch_keylist_pop(keys)))
2350 bkey_put(c, k);
2351 } else if (op.op.insert_collision)
2352 ret = -ESRCH;
2353
2354 return ret;
2355}
2356
2357void bch_btree_set_root(struct btree *b)
2358{
2359 unsigned int i;
2360 struct closure cl;
2361
2362 closure_init_stack(&cl);
2363
2364 trace_bcache_btree_set_root(b);
2365
2366 BUG_ON(!b->written);
2367
2368 for (i = 0; i < KEY_PTRS(&b->key); i++)
2369 BUG_ON(PTR_BUCKET(b->c, &b->key, i)->prio != BTREE_PRIO);
2370
2371 mutex_lock(&b->c->bucket_lock);
2372 list_del_init(&b->list);
2373 mutex_unlock(&b->c->bucket_lock);
2374
2375 b->c->root = b;
2376
2377 bch_journal_meta(b->c, &cl);
2378 closure_sync(&cl);
2379}
2380
2381/* Map across nodes or keys */
2382
2383static int bch_btree_map_nodes_recurse(struct btree *b, struct btree_op *op,
2384 struct bkey *from,
2385 btree_map_nodes_fn *fn, int flags)
2386{
2387 int ret = MAP_CONTINUE;
2388
2389 if (b->level) {
2390 struct bkey *k;
2391 struct btree_iter iter;
2392
2393 bch_btree_iter_init(&b->keys, &iter, from);
2394
2395 while ((k = bch_btree_iter_next_filter(&iter, &b->keys,
2396 bch_ptr_bad))) {
2397 ret = btree(map_nodes_recurse, k, b,
2398 op, from, fn, flags);
2399 from = NULL;
2400
2401 if (ret != MAP_CONTINUE)
2402 return ret;
2403 }
2404 }
2405
2406 if (!b->level || flags == MAP_ALL_NODES)
2407 ret = fn(op, b);
2408
2409 return ret;
2410}
2411
2412int __bch_btree_map_nodes(struct btree_op *op, struct cache_set *c,
2413 struct bkey *from, btree_map_nodes_fn *fn, int flags)
2414{
2415 return btree_root(map_nodes_recurse, c, op, from, fn, flags);
2416}
2417
2418static int bch_btree_map_keys_recurse(struct btree *b, struct btree_op *op,
2419 struct bkey *from, btree_map_keys_fn *fn,
2420 int flags)
2421{
2422 int ret = MAP_CONTINUE;
2423 struct bkey *k;
2424 struct btree_iter iter;
2425
2426 bch_btree_iter_init(&b->keys, &iter, from);
2427
2428 while ((k = bch_btree_iter_next_filter(&iter, &b->keys, bch_ptr_bad))) {
2429 ret = !b->level
2430 ? fn(op, b, k)
2431 : btree(map_keys_recurse, k, b, op, from, fn, flags);
2432 from = NULL;
2433
2434 if (ret != MAP_CONTINUE)
2435 return ret;
2436 }
2437
2438 if (!b->level && (flags & MAP_END_KEY))
2439 ret = fn(op, b, &KEY(KEY_INODE(&b->key),
2440 KEY_OFFSET(&b->key), 0));
2441
2442 return ret;
2443}
2444
2445int bch_btree_map_keys(struct btree_op *op, struct cache_set *c,
2446 struct bkey *from, btree_map_keys_fn *fn, int flags)
2447{
2448 return btree_root(map_keys_recurse, c, op, from, fn, flags);
2449}
2450
2451/* Keybuf code */
2452
2453static inline int keybuf_cmp(struct keybuf_key *l, struct keybuf_key *r)
2454{
2455 /* Overlapping keys compare equal */
2456 if (bkey_cmp(&l->key, &START_KEY(&r->key)) <= 0)
2457 return -1;
2458 if (bkey_cmp(&START_KEY(&l->key), &r->key) >= 0)
2459 return 1;
2460 return 0;
2461}
2462
2463static inline int keybuf_nonoverlapping_cmp(struct keybuf_key *l,
2464 struct keybuf_key *r)
2465{
2466 return clamp_t(int64_t, bkey_cmp(&l->key, &r->key), -1, 1);
2467}
2468
2469struct refill {
2470 struct btree_op op;
2471 unsigned int nr_found;
2472 struct keybuf *buf;
2473 struct bkey *end;
2474 keybuf_pred_fn *pred;
2475};
2476
2477static int refill_keybuf_fn(struct btree_op *op, struct btree *b,
2478 struct bkey *k)
2479{
2480 struct refill *refill = container_of(op, struct refill, op);
2481 struct keybuf *buf = refill->buf;
2482 int ret = MAP_CONTINUE;
2483
2484 if (bkey_cmp(k, refill->end) > 0) {
2485 ret = MAP_DONE;
2486 goto out;
2487 }
2488
2489 if (!KEY_SIZE(k)) /* end key */
2490 goto out;
2491
2492 if (refill->pred(buf, k)) {
2493 struct keybuf_key *w;
2494
2495 spin_lock(&buf->lock);
2496
2497 w = array_alloc(&buf->freelist);
2498 if (!w) {
2499 spin_unlock(&buf->lock);
2500 return MAP_DONE;
2501 }
2502
2503 w->private = NULL;
2504 bkey_copy(&w->key, k);
2505
2506 if (RB_INSERT(&buf->keys, w, node, keybuf_cmp))
2507 array_free(&buf->freelist, w);
2508 else
2509 refill->nr_found++;
2510
2511 if (array_freelist_empty(&buf->freelist))
2512 ret = MAP_DONE;
2513
2514 spin_unlock(&buf->lock);
2515 }
2516out:
2517 buf->last_scanned = *k;
2518 return ret;
2519}
2520
2521void bch_refill_keybuf(struct cache_set *c, struct keybuf *buf,
2522 struct bkey *end, keybuf_pred_fn *pred)
2523{
2524 struct bkey start = buf->last_scanned;
2525 struct refill refill;
2526
2527 cond_resched();
2528
2529 bch_btree_op_init(&refill.op, -1);
2530 refill.nr_found = 0;
2531 refill.buf = buf;
2532 refill.end = end;
2533 refill.pred = pred;
2534
2535 bch_btree_map_keys(&refill.op, c, &buf->last_scanned,
2536 refill_keybuf_fn, MAP_END_KEY);
2537
2538 trace_bcache_keyscan(refill.nr_found,
2539 KEY_INODE(&start), KEY_OFFSET(&start),
2540 KEY_INODE(&buf->last_scanned),
2541 KEY_OFFSET(&buf->last_scanned));
2542
2543 spin_lock(&buf->lock);
2544
2545 if (!RB_EMPTY_ROOT(&buf->keys)) {
2546 struct keybuf_key *w;
2547
2548 w = RB_FIRST(&buf->keys, struct keybuf_key, node);
2549 buf->start = START_KEY(&w->key);
2550
2551 w = RB_LAST(&buf->keys, struct keybuf_key, node);
2552 buf->end = w->key;
2553 } else {
2554 buf->start = MAX_KEY;
2555 buf->end = MAX_KEY;
2556 }
2557
2558 spin_unlock(&buf->lock);
2559}
2560
2561static void __bch_keybuf_del(struct keybuf *buf, struct keybuf_key *w)
2562{
2563 rb_erase(&w->node, &buf->keys);
2564 array_free(&buf->freelist, w);
2565}
2566
2567void bch_keybuf_del(struct keybuf *buf, struct keybuf_key *w)
2568{
2569 spin_lock(&buf->lock);
2570 __bch_keybuf_del(buf, w);
2571 spin_unlock(&buf->lock);
2572}
2573
2574bool bch_keybuf_check_overlapping(struct keybuf *buf, struct bkey *start,
2575 struct bkey *end)
2576{
2577 bool ret = false;
2578 struct keybuf_key *p, *w, s;
2579
2580 s.key = *start;
2581
2582 if (bkey_cmp(end, &buf->start) <= 0 ||
2583 bkey_cmp(start, &buf->end) >= 0)
2584 return false;
2585
2586 spin_lock(&buf->lock);
2587 w = RB_GREATER(&buf->keys, s, node, keybuf_nonoverlapping_cmp);
2588
2589 while (w && bkey_cmp(&START_KEY(&w->key), end) < 0) {
2590 p = w;
2591 w = RB_NEXT(w, node);
2592
2593 if (p->private)
2594 ret = true;
2595 else
2596 __bch_keybuf_del(buf, p);
2597 }
2598
2599 spin_unlock(&buf->lock);
2600 return ret;
2601}
2602
2603struct keybuf_key *bch_keybuf_next(struct keybuf *buf)
2604{
2605 struct keybuf_key *w;
2606
2607 spin_lock(&buf->lock);
2608
2609 w = RB_FIRST(&buf->keys, struct keybuf_key, node);
2610
2611 while (w && w->private)
2612 w = RB_NEXT(w, node);
2613
2614 if (w)
2615 w->private = ERR_PTR(-EINTR);
2616
2617 spin_unlock(&buf->lock);
2618 return w;
2619}
2620
2621struct keybuf_key *bch_keybuf_next_rescan(struct cache_set *c,
2622 struct keybuf *buf,
2623 struct bkey *end,
2624 keybuf_pred_fn *pred)
2625{
2626 struct keybuf_key *ret;
2627
2628 while (1) {
2629 ret = bch_keybuf_next(buf);
2630 if (ret)
2631 break;
2632
2633 if (bkey_cmp(&buf->last_scanned, end) >= 0) {
2634 pr_debug("scan finished");
2635 break;
2636 }
2637
2638 bch_refill_keybuf(c, buf, end, pred);
2639 }
2640
2641 return ret;
2642}
2643
2644void bch_keybuf_init(struct keybuf *buf)
2645{
2646 buf->last_scanned = MAX_KEY;
2647 buf->keys = RB_ROOT;
2648
2649 spin_lock_init(&buf->lock);
2650 array_allocator_init(&buf->freelist);
2651}