1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2010 Kent Overstreet <kent.overstreet@gmail.com>
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
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.
14 * Buckets have an 8 bit counter; freeing is accomplished by incrementing the
15 * counter. Garbage collection is used to remove stale pointers.
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.
21 * All configuration is done via sysfs; see Documentation/bcache.txt.
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>
39 #include <trace/events/bcache.h>
43 * register_bcache: Return errors out to userspace correctly
45 * Writeback: don't undirty key until after a cache flush
47 * Create an iterator for key pointers
49 * On btree write error, mark bucket such that it won't be freed from the cache
52 * Check for bad keys in replay
54 * Refcount journal entries in journal_replay
57 * Finish incremental gc
58 * Gc should free old UUIDs, data for invalid UUIDs
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
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
68 * Add a tracepoint or somesuch to watch for writeback starvation
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
76 * If data write is less than hard sector size of ssd, round up offset in open
77 * bucket to the next whole sector
79 * Superblock needs to be fleshed out for multiple cache devices
81 * Add a sysfs tunable for the number of writeback IOs in flight
83 * Add a sysfs tunable for the number of open data buckets
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
88 * Test module load/unload
91 #define MAX_NEED_GC 64
92 #define MAX_SAVE_PRIO 72
94 #define PTR_DIRTY_BIT (((uint64_t) 1 << 36))
96 #define PTR_HASH(c, k) \
97 (((k)->ptr[0] >> c->bucket_bits) | PTR_GEN(k, 0))
99 #define insert_lock(s, b) ((b)->level <= (s)->lock)
102 * These macros are for recursing down the btree - they handle the details of
103 * locking and looking up nodes in the cache for you. They're best treated as
104 * mere syntax when reading code that uses them.
106 * op->lock determines whether we take a read or a write lock at a given depth.
107 * If you've got a read lock and find that you need a write lock (i.e. you're
108 * going to have to split), set op->lock and return -EINTR; btree_root() will
109 * call you again and you'll have the correct lock.
113 * btree - recurse down the btree on a specified key
114 * @fn: function to call, which will be passed the child node
115 * @key: key to recurse on
116 * @b: parent btree node
117 * @op: pointer to struct btree_op
119 #define btree(fn, key, b, op, ...) \
121 int _r, l = (b)->level - 1; \
122 bool _w = l <= (op)->lock; \
123 struct btree *_child = bch_btree_node_get((b)->c, op, key, l, \
125 if (!IS_ERR(_child)) { \
126 _r = bch_btree_ ## fn(_child, op, ##__VA_ARGS__); \
127 rw_unlock(_w, _child); \
129 _r = PTR_ERR(_child); \
134 * btree_root - call a function on the root of the btree
135 * @fn: function to call, which will be passed the child node
137 * @op: pointer to struct btree_op
139 #define btree_root(fn, c, op, ...) \
143 struct btree *_b = (c)->root; \
144 bool _w = insert_lock(op, _b); \
145 rw_lock(_w, _b, _b->level); \
146 if (_b == (c)->root && \
147 _w == insert_lock(op, _b)) { \
148 _r = bch_btree_ ## fn(_b, op, ##__VA_ARGS__); \
151 bch_cannibalize_unlock(c); \
154 } while (_r == -EINTR); \
156 finish_wait(&(c)->btree_cache_wait, &(op)->wait); \
160 static inline struct bset *write_block(struct btree *b)
162 return ((void *) btree_bset_first(b)) + b->written * block_bytes(b->c);
165 static void bch_btree_init_next(struct btree *b)
167 /* If not a leaf node, always sort */
168 if (b->level && b->keys.nsets)
169 bch_btree_sort(&b->keys, &b->c->sort);
171 bch_btree_sort_lazy(&b->keys, &b->c->sort);
173 if (b->written < btree_blocks(b))
174 bch_bset_init_next(&b->keys, write_block(b),
175 bset_magic(&b->c->sb));
179 /* Btree key manipulation */
181 void bkey_put(struct cache_set *c, struct bkey *k)
185 for (i = 0; i < KEY_PTRS(k); i++)
186 if (ptr_available(c, k, i))
187 atomic_dec_bug(&PTR_BUCKET(c, k, i)->pin);
192 static uint64_t btree_csum_set(struct btree *b, struct bset *i)
194 uint64_t crc = b->key.ptr[0];
195 void *data = (void *) i + 8, *end = bset_bkey_last(i);
197 crc = bch_crc64_update(crc, data, end - data);
198 return crc ^ 0xffffffffffffffffULL;
201 void bch_btree_node_read_done(struct btree *b)
203 const char *err = "bad btree header";
204 struct bset *i = btree_bset_first(b);
205 struct btree_iter *iter;
207 iter = mempool_alloc(&b->c->fill_iter, GFP_NOIO);
208 iter->size = b->c->sb.bucket_size / b->c->sb.block_size;
211 #ifdef CONFIG_BCACHE_DEBUG
219 b->written < btree_blocks(b) && i->seq == b->keys.set[0].data->seq;
220 i = write_block(b)) {
221 err = "unsupported bset version";
222 if (i->version > BCACHE_BSET_VERSION)
225 err = "bad btree header";
226 if (b->written + set_blocks(i, block_bytes(b->c)) >
231 if (i->magic != bset_magic(&b->c->sb))
234 err = "bad checksum";
235 switch (i->version) {
237 if (i->csum != csum_set(i))
240 case BCACHE_BSET_VERSION:
241 if (i->csum != btree_csum_set(b, i))
247 if (i != b->keys.set[0].data && !i->keys)
250 bch_btree_iter_push(iter, i->start, bset_bkey_last(i));
252 b->written += set_blocks(i, block_bytes(b->c));
255 err = "corrupted btree";
256 for (i = write_block(b);
257 bset_sector_offset(&b->keys, i) < KEY_SIZE(&b->key);
258 i = ((void *) i) + block_bytes(b->c))
259 if (i->seq == b->keys.set[0].data->seq)
262 bch_btree_sort_and_fix_extents(&b->keys, iter, &b->c->sort);
264 i = b->keys.set[0].data;
265 err = "short btree key";
266 if (b->keys.set[0].size &&
267 bkey_cmp(&b->key, &b->keys.set[0].end) < 0)
270 if (b->written < btree_blocks(b))
271 bch_bset_init_next(&b->keys, write_block(b),
272 bset_magic(&b->c->sb));
274 mempool_free(iter, &b->c->fill_iter);
277 set_btree_node_io_error(b);
278 bch_cache_set_error(b->c, "%s at bucket %zu, block %u, %u keys",
279 err, PTR_BUCKET_NR(b->c, &b->key, 0),
280 bset_block_offset(b, i), i->keys);
284 static void btree_node_read_endio(struct bio *bio)
286 struct closure *cl = bio->bi_private;
290 static void bch_btree_node_read(struct btree *b)
292 uint64_t start_time = local_clock();
296 trace_bcache_btree_read(b);
298 closure_init_stack(&cl);
300 bio = bch_bbio_alloc(b->c);
301 bio->bi_iter.bi_size = KEY_SIZE(&b->key) << 9;
302 bio->bi_end_io = btree_node_read_endio;
303 bio->bi_private = &cl;
304 bio->bi_opf = REQ_OP_READ | REQ_META;
306 bch_bio_map(bio, b->keys.set[0].data);
308 bch_submit_bbio(bio, b->c, &b->key, 0);
312 set_btree_node_io_error(b);
314 bch_bbio_free(bio, b->c);
316 if (btree_node_io_error(b))
319 bch_btree_node_read_done(b);
320 bch_time_stats_update(&b->c->btree_read_time, start_time);
324 bch_cache_set_error(b->c, "io error reading bucket %zu",
325 PTR_BUCKET_NR(b->c, &b->key, 0));
328 static void btree_complete_write(struct btree *b, struct btree_write *w)
330 if (w->prio_blocked &&
331 !atomic_sub_return(w->prio_blocked, &b->c->prio_blocked))
332 wake_up_allocators(b->c);
335 atomic_dec_bug(w->journal);
336 __closure_wake_up(&b->c->journal.wait);
343 static void btree_node_write_unlock(struct closure *cl)
345 struct btree *b = container_of(cl, struct btree, io);
350 static void __btree_node_write_done(struct closure *cl)
352 struct btree *b = container_of(cl, struct btree, io);
353 struct btree_write *w = btree_prev_write(b);
355 bch_bbio_free(b->bio, b->c);
357 btree_complete_write(b, w);
359 if (btree_node_dirty(b))
360 schedule_delayed_work(&b->work, 30 * HZ);
362 closure_return_with_destructor(cl, btree_node_write_unlock);
365 static void btree_node_write_done(struct closure *cl)
367 struct btree *b = container_of(cl, struct btree, io);
369 bio_free_pages(b->bio);
370 __btree_node_write_done(cl);
373 static void btree_node_write_endio(struct bio *bio)
375 struct closure *cl = bio->bi_private;
376 struct btree *b = container_of(cl, struct btree, io);
379 set_btree_node_io_error(b);
381 bch_bbio_count_io_errors(b->c, bio, bio->bi_status, "writing btree");
385 static void do_btree_node_write(struct btree *b)
387 struct closure *cl = &b->io;
388 struct bset *i = btree_bset_last(b);
391 i->version = BCACHE_BSET_VERSION;
392 i->csum = btree_csum_set(b, i);
395 b->bio = bch_bbio_alloc(b->c);
397 b->bio->bi_end_io = btree_node_write_endio;
398 b->bio->bi_private = cl;
399 b->bio->bi_iter.bi_size = roundup(set_bytes(i), block_bytes(b->c));
400 b->bio->bi_opf = REQ_OP_WRITE | REQ_META | REQ_FUA;
401 bch_bio_map(b->bio, i);
404 * If we're appending to a leaf node, we don't technically need FUA -
405 * this write just needs to be persisted before the next journal write,
406 * which will be marked FLUSH|FUA.
408 * Similarly if we're writing a new btree root - the pointer is going to
409 * be in the next journal entry.
411 * But if we're writing a new btree node (that isn't a root) or
412 * appending to a non leaf btree node, we need either FUA or a flush
413 * when we write the parent with the new pointer. FUA is cheaper than a
414 * flush, and writes appending to leaf nodes aren't blocking anything so
415 * just make all btree node writes FUA to keep things sane.
418 bkey_copy(&k.key, &b->key);
419 SET_PTR_OFFSET(&k.key, 0, PTR_OFFSET(&k.key, 0) +
420 bset_sector_offset(&b->keys, i));
422 if (!bch_bio_alloc_pages(b->bio, __GFP_NOWARN|GFP_NOWAIT)) {
425 void *base = (void *) ((unsigned long) i & ~(PAGE_SIZE - 1));
427 bio_for_each_segment_all(bv, b->bio, j)
428 memcpy(page_address(bv->bv_page),
429 base + j * PAGE_SIZE, PAGE_SIZE);
431 bch_submit_bbio(b->bio, b->c, &k.key, 0);
433 continue_at(cl, btree_node_write_done, NULL);
435 /* No problem for multipage bvec since the bio is just allocated */
437 bch_bio_map(b->bio, i);
439 bch_submit_bbio(b->bio, b->c, &k.key, 0);
442 continue_at_nobarrier(cl, __btree_node_write_done, NULL);
446 void __bch_btree_node_write(struct btree *b, struct closure *parent)
448 struct bset *i = btree_bset_last(b);
450 lockdep_assert_held(&b->write_lock);
452 trace_bcache_btree_write(b);
454 BUG_ON(current->bio_list);
455 BUG_ON(b->written >= btree_blocks(b));
456 BUG_ON(b->written && !i->keys);
457 BUG_ON(btree_bset_first(b)->seq != i->seq);
458 bch_check_keys(&b->keys, "writing");
460 cancel_delayed_work(&b->work);
462 /* If caller isn't waiting for write, parent refcount is cache set */
464 closure_init(&b->io, parent ?: &b->c->cl);
466 clear_bit(BTREE_NODE_dirty, &b->flags);
467 change_bit(BTREE_NODE_write_idx, &b->flags);
469 do_btree_node_write(b);
471 atomic_long_add(set_blocks(i, block_bytes(b->c)) * b->c->sb.block_size,
472 &PTR_CACHE(b->c, &b->key, 0)->btree_sectors_written);
474 b->written += set_blocks(i, block_bytes(b->c));
477 void bch_btree_node_write(struct btree *b, struct closure *parent)
479 unsigned nsets = b->keys.nsets;
481 lockdep_assert_held(&b->lock);
483 __bch_btree_node_write(b, parent);
486 * do verify if there was more than one set initially (i.e. we did a
487 * sort) and we sorted down to a single set:
489 if (nsets && !b->keys.nsets)
492 bch_btree_init_next(b);
495 static void bch_btree_node_write_sync(struct btree *b)
499 closure_init_stack(&cl);
501 mutex_lock(&b->write_lock);
502 bch_btree_node_write(b, &cl);
503 mutex_unlock(&b->write_lock);
508 static void btree_node_write_work(struct work_struct *w)
510 struct btree *b = container_of(to_delayed_work(w), struct btree, work);
512 mutex_lock(&b->write_lock);
513 if (btree_node_dirty(b))
514 __bch_btree_node_write(b, NULL);
515 mutex_unlock(&b->write_lock);
518 static void bch_btree_leaf_dirty(struct btree *b, atomic_t *journal_ref)
520 struct bset *i = btree_bset_last(b);
521 struct btree_write *w = btree_current_write(b);
523 lockdep_assert_held(&b->write_lock);
528 if (!btree_node_dirty(b))
529 schedule_delayed_work(&b->work, 30 * HZ);
531 set_btree_node_dirty(b);
535 journal_pin_cmp(b->c, w->journal, journal_ref)) {
536 atomic_dec_bug(w->journal);
541 w->journal = journal_ref;
542 atomic_inc(w->journal);
546 /* Force write if set is too big */
547 if (set_bytes(i) > PAGE_SIZE - 48 &&
549 bch_btree_node_write(b, NULL);
553 * Btree in memory cache - allocation/freeing
554 * mca -> memory cache
557 #define mca_reserve(c) (((c->root && c->root->level) \
558 ? c->root->level : 1) * 8 + 16)
559 #define mca_can_free(c) \
560 max_t(int, 0, c->btree_cache_used - mca_reserve(c))
562 static void mca_data_free(struct btree *b)
564 BUG_ON(b->io_mutex.count != 1);
566 bch_btree_keys_free(&b->keys);
568 b->c->btree_cache_used--;
569 list_move(&b->list, &b->c->btree_cache_freed);
572 static void mca_bucket_free(struct btree *b)
574 BUG_ON(btree_node_dirty(b));
577 hlist_del_init_rcu(&b->hash);
578 list_move(&b->list, &b->c->btree_cache_freeable);
581 static unsigned btree_order(struct bkey *k)
583 return ilog2(KEY_SIZE(k) / PAGE_SECTORS ?: 1);
586 static void mca_data_alloc(struct btree *b, struct bkey *k, gfp_t gfp)
588 if (!bch_btree_keys_alloc(&b->keys,
590 ilog2(b->c->btree_pages),
593 b->c->btree_cache_used++;
594 list_move(&b->list, &b->c->btree_cache);
596 list_move(&b->list, &b->c->btree_cache_freed);
600 static struct btree *mca_bucket_alloc(struct cache_set *c,
601 struct bkey *k, gfp_t gfp)
603 struct btree *b = kzalloc(sizeof(struct btree), gfp);
607 init_rwsem(&b->lock);
608 lockdep_set_novalidate_class(&b->lock);
609 mutex_init(&b->write_lock);
610 lockdep_set_novalidate_class(&b->write_lock);
611 INIT_LIST_HEAD(&b->list);
612 INIT_DELAYED_WORK(&b->work, btree_node_write_work);
614 sema_init(&b->io_mutex, 1);
616 mca_data_alloc(b, k, gfp);
620 static int mca_reap(struct btree *b, unsigned min_order, bool flush)
624 closure_init_stack(&cl);
625 lockdep_assert_held(&b->c->bucket_lock);
627 if (!down_write_trylock(&b->lock))
630 BUG_ON(btree_node_dirty(b) && !b->keys.set[0].data);
632 if (b->keys.page_order < min_order)
636 if (btree_node_dirty(b))
639 if (down_trylock(&b->io_mutex))
644 mutex_lock(&b->write_lock);
645 if (btree_node_dirty(b))
646 __bch_btree_node_write(b, &cl);
647 mutex_unlock(&b->write_lock);
651 /* wait for any in flight btree write */
661 static unsigned long bch_mca_scan(struct shrinker *shrink,
662 struct shrink_control *sc)
664 struct cache_set *c = container_of(shrink, struct cache_set, shrink);
666 unsigned long i, nr = sc->nr_to_scan;
667 unsigned long freed = 0;
668 unsigned int btree_cache_used;
670 if (c->shrinker_disabled)
673 if (c->btree_cache_alloc_lock)
676 /* Return -1 if we can't do anything right now */
677 if (sc->gfp_mask & __GFP_IO)
678 mutex_lock(&c->bucket_lock);
679 else if (!mutex_trylock(&c->bucket_lock))
683 * It's _really_ critical that we don't free too many btree nodes - we
684 * have to always leave ourselves a reserve. The reserve is how we
685 * guarantee that allocating memory for a new btree node can always
686 * succeed, so that inserting keys into the btree can always succeed and
687 * IO can always make forward progress:
689 nr /= c->btree_pages;
690 nr = min_t(unsigned long, nr, mca_can_free(c));
693 btree_cache_used = c->btree_cache_used;
694 list_for_each_entry_safe(b, t, &c->btree_cache_freeable, list) {
699 !mca_reap(b, 0, false)) {
707 for (; (nr--) && i < btree_cache_used; i++) {
708 if (list_empty(&c->btree_cache))
711 b = list_first_entry(&c->btree_cache, struct btree, list);
712 list_rotate_left(&c->btree_cache);
715 !mca_reap(b, 0, false)) {
724 mutex_unlock(&c->bucket_lock);
725 return freed * c->btree_pages;
728 static unsigned long bch_mca_count(struct shrinker *shrink,
729 struct shrink_control *sc)
731 struct cache_set *c = container_of(shrink, struct cache_set, shrink);
733 if (c->shrinker_disabled)
736 if (c->btree_cache_alloc_lock)
739 return mca_can_free(c) * c->btree_pages;
742 void bch_btree_cache_free(struct cache_set *c)
746 closure_init_stack(&cl);
748 if (c->shrink.list.next)
749 unregister_shrinker(&c->shrink);
751 mutex_lock(&c->bucket_lock);
753 #ifdef CONFIG_BCACHE_DEBUG
755 list_move(&c->verify_data->list, &c->btree_cache);
757 free_pages((unsigned long) c->verify_ondisk, ilog2(bucket_pages(c)));
760 list_splice(&c->btree_cache_freeable,
763 while (!list_empty(&c->btree_cache)) {
764 b = list_first_entry(&c->btree_cache, struct btree, list);
766 if (btree_node_dirty(b))
767 btree_complete_write(b, btree_current_write(b));
768 clear_bit(BTREE_NODE_dirty, &b->flags);
773 while (!list_empty(&c->btree_cache_freed)) {
774 b = list_first_entry(&c->btree_cache_freed,
777 cancel_delayed_work_sync(&b->work);
781 mutex_unlock(&c->bucket_lock);
784 int bch_btree_cache_alloc(struct cache_set *c)
788 for (i = 0; i < mca_reserve(c); i++)
789 if (!mca_bucket_alloc(c, &ZERO_KEY, GFP_KERNEL))
792 list_splice_init(&c->btree_cache,
793 &c->btree_cache_freeable);
795 #ifdef CONFIG_BCACHE_DEBUG
796 mutex_init(&c->verify_lock);
798 c->verify_ondisk = (void *)
799 __get_free_pages(GFP_KERNEL, ilog2(bucket_pages(c)));
801 c->verify_data = mca_bucket_alloc(c, &ZERO_KEY, GFP_KERNEL);
803 if (c->verify_data &&
804 c->verify_data->keys.set->data)
805 list_del_init(&c->verify_data->list);
807 c->verify_data = NULL;
810 c->shrink.count_objects = bch_mca_count;
811 c->shrink.scan_objects = bch_mca_scan;
813 c->shrink.batch = c->btree_pages * 2;
815 if (register_shrinker(&c->shrink))
816 pr_warn("bcache: %s: could not register shrinker",
822 /* Btree in memory cache - hash table */
824 static struct hlist_head *mca_hash(struct cache_set *c, struct bkey *k)
826 return &c->bucket_hash[hash_32(PTR_HASH(c, k), BUCKET_HASH_BITS)];
829 static struct btree *mca_find(struct cache_set *c, struct bkey *k)
834 hlist_for_each_entry_rcu(b, mca_hash(c, k), hash)
835 if (PTR_HASH(c, &b->key) == PTR_HASH(c, k))
843 static int mca_cannibalize_lock(struct cache_set *c, struct btree_op *op)
845 struct task_struct *old;
847 old = cmpxchg(&c->btree_cache_alloc_lock, NULL, current);
848 if (old && old != current) {
850 prepare_to_wait(&c->btree_cache_wait, &op->wait,
851 TASK_UNINTERRUPTIBLE);
858 static struct btree *mca_cannibalize(struct cache_set *c, struct btree_op *op,
863 trace_bcache_btree_cache_cannibalize(c);
865 if (mca_cannibalize_lock(c, op))
866 return ERR_PTR(-EINTR);
868 list_for_each_entry_reverse(b, &c->btree_cache, list)
869 if (!mca_reap(b, btree_order(k), false))
872 list_for_each_entry_reverse(b, &c->btree_cache, list)
873 if (!mca_reap(b, btree_order(k), true))
876 WARN(1, "btree cache cannibalize failed\n");
877 return ERR_PTR(-ENOMEM);
881 * We can only have one thread cannibalizing other cached btree nodes at a time,
882 * or we'll deadlock. We use an open coded mutex to ensure that, which a
883 * cannibalize_bucket() will take. This means every time we unlock the root of
884 * the btree, we need to release this lock if we have it held.
886 static void bch_cannibalize_unlock(struct cache_set *c)
888 if (c->btree_cache_alloc_lock == current) {
889 c->btree_cache_alloc_lock = NULL;
890 wake_up(&c->btree_cache_wait);
894 static struct btree *mca_alloc(struct cache_set *c, struct btree_op *op,
895 struct bkey *k, int level)
899 BUG_ON(current->bio_list);
901 lockdep_assert_held(&c->bucket_lock);
906 /* btree_free() doesn't free memory; it sticks the node on the end of
907 * the list. Check if there's any freed nodes there:
909 list_for_each_entry(b, &c->btree_cache_freeable, list)
910 if (!mca_reap(b, btree_order(k), false))
913 /* We never free struct btree itself, just the memory that holds the on
914 * disk node. Check the freed list before allocating a new one:
916 list_for_each_entry(b, &c->btree_cache_freed, list)
917 if (!mca_reap(b, 0, false)) {
918 mca_data_alloc(b, k, __GFP_NOWARN|GFP_NOIO);
919 if (!b->keys.set[0].data)
925 b = mca_bucket_alloc(c, k, __GFP_NOWARN|GFP_NOIO);
929 BUG_ON(!down_write_trylock(&b->lock));
930 if (!b->keys.set->data)
933 BUG_ON(b->io_mutex.count != 1);
935 bkey_copy(&b->key, k);
936 list_move(&b->list, &c->btree_cache);
937 hlist_del_init_rcu(&b->hash);
938 hlist_add_head_rcu(&b->hash, mca_hash(c, k));
940 lock_set_subclass(&b->lock.dep_map, level + 1, _THIS_IP_);
941 b->parent = (void *) ~0UL;
947 bch_btree_keys_init(&b->keys, &bch_extent_keys_ops,
948 &b->c->expensive_debug_checks);
950 bch_btree_keys_init(&b->keys, &bch_btree_keys_ops,
951 &b->c->expensive_debug_checks);
958 b = mca_cannibalize(c, op, k);
966 * bch_btree_node_get - find a btree node in the cache and lock it, reading it
967 * in from disk if necessary.
969 * If IO is necessary and running under generic_make_request, returns -EAGAIN.
971 * The btree node will have either a read or a write lock held, depending on
972 * level and op->lock.
974 struct btree *bch_btree_node_get(struct cache_set *c, struct btree_op *op,
975 struct bkey *k, int level, bool write,
976 struct btree *parent)
986 if (current->bio_list)
987 return ERR_PTR(-EAGAIN);
989 mutex_lock(&c->bucket_lock);
990 b = mca_alloc(c, op, k, level);
991 mutex_unlock(&c->bucket_lock);
998 bch_btree_node_read(b);
1001 downgrade_write(&b->lock);
1003 rw_lock(write, b, level);
1004 if (PTR_HASH(c, &b->key) != PTR_HASH(c, k)) {
1005 rw_unlock(write, b);
1008 BUG_ON(b->level != level);
1014 for (; i <= b->keys.nsets && b->keys.set[i].size; i++) {
1015 prefetch(b->keys.set[i].tree);
1016 prefetch(b->keys.set[i].data);
1019 for (; i <= b->keys.nsets; i++)
1020 prefetch(b->keys.set[i].data);
1022 if (btree_node_io_error(b)) {
1023 rw_unlock(write, b);
1024 return ERR_PTR(-EIO);
1027 BUG_ON(!b->written);
1032 static void btree_node_prefetch(struct btree *parent, struct bkey *k)
1036 mutex_lock(&parent->c->bucket_lock);
1037 b = mca_alloc(parent->c, NULL, k, parent->level - 1);
1038 mutex_unlock(&parent->c->bucket_lock);
1040 if (!IS_ERR_OR_NULL(b)) {
1042 bch_btree_node_read(b);
1049 static void btree_node_free(struct btree *b)
1051 trace_bcache_btree_node_free(b);
1053 BUG_ON(b == b->c->root);
1055 mutex_lock(&b->write_lock);
1057 if (btree_node_dirty(b))
1058 btree_complete_write(b, btree_current_write(b));
1059 clear_bit(BTREE_NODE_dirty, &b->flags);
1061 mutex_unlock(&b->write_lock);
1063 cancel_delayed_work(&b->work);
1065 mutex_lock(&b->c->bucket_lock);
1066 bch_bucket_free(b->c, &b->key);
1068 mutex_unlock(&b->c->bucket_lock);
1071 struct btree *__bch_btree_node_alloc(struct cache_set *c, struct btree_op *op,
1072 int level, bool wait,
1073 struct btree *parent)
1076 struct btree *b = ERR_PTR(-EAGAIN);
1078 mutex_lock(&c->bucket_lock);
1080 if (__bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, 1, wait))
1083 bkey_put(c, &k.key);
1084 SET_KEY_SIZE(&k.key, c->btree_pages * PAGE_SECTORS);
1086 b = mca_alloc(c, op, &k.key, level);
1092 "Tried to allocate bucket that was in btree cache");
1098 bch_bset_init_next(&b->keys, b->keys.set->data, bset_magic(&b->c->sb));
1100 mutex_unlock(&c->bucket_lock);
1102 trace_bcache_btree_node_alloc(b);
1105 bch_bucket_free(c, &k.key);
1107 mutex_unlock(&c->bucket_lock);
1109 trace_bcache_btree_node_alloc_fail(c);
1113 static struct btree *bch_btree_node_alloc(struct cache_set *c,
1114 struct btree_op *op, int level,
1115 struct btree *parent)
1117 return __bch_btree_node_alloc(c, op, level, op != NULL, parent);
1120 static struct btree *btree_node_alloc_replacement(struct btree *b,
1121 struct btree_op *op)
1123 struct btree *n = bch_btree_node_alloc(b->c, op, b->level, b->parent);
1124 if (!IS_ERR_OR_NULL(n)) {
1125 mutex_lock(&n->write_lock);
1126 bch_btree_sort_into(&b->keys, &n->keys, &b->c->sort);
1127 bkey_copy_key(&n->key, &b->key);
1128 mutex_unlock(&n->write_lock);
1134 static void make_btree_freeing_key(struct btree *b, struct bkey *k)
1138 mutex_lock(&b->c->bucket_lock);
1140 atomic_inc(&b->c->prio_blocked);
1142 bkey_copy(k, &b->key);
1143 bkey_copy_key(k, &ZERO_KEY);
1145 for (i = 0; i < KEY_PTRS(k); i++)
1147 bch_inc_gen(PTR_CACHE(b->c, &b->key, i),
1148 PTR_BUCKET(b->c, &b->key, i)));
1150 mutex_unlock(&b->c->bucket_lock);
1153 static int btree_check_reserve(struct btree *b, struct btree_op *op)
1155 struct cache_set *c = b->c;
1157 unsigned i, reserve = (c->root->level - b->level) * 2 + 1;
1159 mutex_lock(&c->bucket_lock);
1161 for_each_cache(ca, c, i)
1162 if (fifo_used(&ca->free[RESERVE_BTREE]) < reserve) {
1164 prepare_to_wait(&c->btree_cache_wait, &op->wait,
1165 TASK_UNINTERRUPTIBLE);
1166 mutex_unlock(&c->bucket_lock);
1170 mutex_unlock(&c->bucket_lock);
1172 return mca_cannibalize_lock(b->c, op);
1175 /* Garbage collection */
1177 static uint8_t __bch_btree_mark_key(struct cache_set *c, int level,
1185 * ptr_invalid() can't return true for the keys that mark btree nodes as
1186 * freed, but since ptr_bad() returns true we'll never actually use them
1187 * for anything and thus we don't want mark their pointers here
1189 if (!bkey_cmp(k, &ZERO_KEY))
1192 for (i = 0; i < KEY_PTRS(k); i++) {
1193 if (!ptr_available(c, k, i))
1196 g = PTR_BUCKET(c, k, i);
1198 if (gen_after(g->last_gc, PTR_GEN(k, i)))
1199 g->last_gc = PTR_GEN(k, i);
1201 if (ptr_stale(c, k, i)) {
1202 stale = max(stale, ptr_stale(c, k, i));
1206 cache_bug_on(GC_MARK(g) &&
1207 (GC_MARK(g) == GC_MARK_METADATA) != (level != 0),
1208 c, "inconsistent ptrs: mark = %llu, level = %i",
1212 SET_GC_MARK(g, GC_MARK_METADATA);
1213 else if (KEY_DIRTY(k))
1214 SET_GC_MARK(g, GC_MARK_DIRTY);
1215 else if (!GC_MARK(g))
1216 SET_GC_MARK(g, GC_MARK_RECLAIMABLE);
1218 /* guard against overflow */
1219 SET_GC_SECTORS_USED(g, min_t(unsigned,
1220 GC_SECTORS_USED(g) + KEY_SIZE(k),
1221 MAX_GC_SECTORS_USED));
1223 BUG_ON(!GC_SECTORS_USED(g));
1229 #define btree_mark_key(b, k) __bch_btree_mark_key(b->c, b->level, k)
1231 void bch_initial_mark_key(struct cache_set *c, int level, struct bkey *k)
1235 for (i = 0; i < KEY_PTRS(k); i++)
1236 if (ptr_available(c, k, i) &&
1237 !ptr_stale(c, k, i)) {
1238 struct bucket *b = PTR_BUCKET(c, k, i);
1240 b->gen = PTR_GEN(k, i);
1242 if (level && bkey_cmp(k, &ZERO_KEY))
1243 b->prio = BTREE_PRIO;
1244 else if (!level && b->prio == BTREE_PRIO)
1245 b->prio = INITIAL_PRIO;
1248 __bch_btree_mark_key(c, level, k);
1251 void bch_update_bucket_in_use(struct cache_set *c, struct gc_stat *stats)
1253 stats->in_use = (c->nbuckets - c->avail_nbuckets) * 100 / c->nbuckets;
1256 static bool btree_gc_mark_node(struct btree *b, struct gc_stat *gc)
1259 unsigned keys = 0, good_keys = 0;
1261 struct btree_iter iter;
1262 struct bset_tree *t;
1266 for_each_key_filter(&b->keys, k, &iter, bch_ptr_invalid) {
1267 stale = max(stale, btree_mark_key(b, k));
1270 if (bch_ptr_bad(&b->keys, k))
1273 gc->key_bytes += bkey_u64s(k);
1277 gc->data += KEY_SIZE(k);
1280 for (t = b->keys.set; t <= &b->keys.set[b->keys.nsets]; t++)
1281 btree_bug_on(t->size &&
1282 bset_written(&b->keys, t) &&
1283 bkey_cmp(&b->key, &t->end) < 0,
1284 b, "found short btree key in gc");
1286 if (b->c->gc_always_rewrite)
1292 if ((keys - good_keys) * 2 > keys)
1298 #define GC_MERGE_NODES 4U
1300 struct gc_merge_info {
1305 static int bch_btree_insert_node(struct btree *, struct btree_op *,
1306 struct keylist *, atomic_t *, struct bkey *);
1308 static int btree_gc_coalesce(struct btree *b, struct btree_op *op,
1309 struct gc_stat *gc, struct gc_merge_info *r)
1311 unsigned i, nodes = 0, keys = 0, blocks;
1312 struct btree *new_nodes[GC_MERGE_NODES];
1313 struct keylist keylist;
1317 bch_keylist_init(&keylist);
1319 if (btree_check_reserve(b, NULL))
1322 memset(new_nodes, 0, sizeof(new_nodes));
1323 closure_init_stack(&cl);
1325 while (nodes < GC_MERGE_NODES && !IS_ERR_OR_NULL(r[nodes].b))
1326 keys += r[nodes++].keys;
1328 blocks = btree_default_blocks(b->c) * 2 / 3;
1331 __set_blocks(b->keys.set[0].data, keys,
1332 block_bytes(b->c)) > blocks * (nodes - 1))
1335 for (i = 0; i < nodes; i++) {
1336 new_nodes[i] = btree_node_alloc_replacement(r[i].b, NULL);
1337 if (IS_ERR_OR_NULL(new_nodes[i]))
1338 goto out_nocoalesce;
1342 * We have to check the reserve here, after we've allocated our new
1343 * nodes, to make sure the insert below will succeed - we also check
1344 * before as an optimization to potentially avoid a bunch of expensive
1347 if (btree_check_reserve(b, NULL))
1348 goto out_nocoalesce;
1350 for (i = 0; i < nodes; i++)
1351 mutex_lock(&new_nodes[i]->write_lock);
1353 for (i = nodes - 1; i > 0; --i) {
1354 struct bset *n1 = btree_bset_first(new_nodes[i]);
1355 struct bset *n2 = btree_bset_first(new_nodes[i - 1]);
1356 struct bkey *k, *last = NULL;
1362 k < bset_bkey_last(n2);
1364 if (__set_blocks(n1, n1->keys + keys +
1366 block_bytes(b->c)) > blocks)
1370 keys += bkey_u64s(k);
1374 * Last node we're not getting rid of - we're getting
1375 * rid of the node at r[0]. Have to try and fit all of
1376 * the remaining keys into this node; we can't ensure
1377 * they will always fit due to rounding and variable
1378 * length keys (shouldn't be possible in practice,
1381 if (__set_blocks(n1, n1->keys + n2->keys,
1382 block_bytes(b->c)) >
1383 btree_blocks(new_nodes[i]))
1384 goto out_nocoalesce;
1387 /* Take the key of the node we're getting rid of */
1391 BUG_ON(__set_blocks(n1, n1->keys + keys, block_bytes(b->c)) >
1392 btree_blocks(new_nodes[i]));
1395 bkey_copy_key(&new_nodes[i]->key, last);
1397 memcpy(bset_bkey_last(n1),
1399 (void *) bset_bkey_idx(n2, keys) - (void *) n2->start);
1402 r[i].keys = n1->keys;
1405 bset_bkey_idx(n2, keys),
1406 (void *) bset_bkey_last(n2) -
1407 (void *) bset_bkey_idx(n2, keys));
1411 if (__bch_keylist_realloc(&keylist,
1412 bkey_u64s(&new_nodes[i]->key)))
1413 goto out_nocoalesce;
1415 bch_btree_node_write(new_nodes[i], &cl);
1416 bch_keylist_add(&keylist, &new_nodes[i]->key);
1419 for (i = 0; i < nodes; i++)
1420 mutex_unlock(&new_nodes[i]->write_lock);
1424 /* We emptied out this node */
1425 BUG_ON(btree_bset_first(new_nodes[0])->keys);
1426 btree_node_free(new_nodes[0]);
1427 rw_unlock(true, new_nodes[0]);
1428 new_nodes[0] = NULL;
1430 for (i = 0; i < nodes; i++) {
1431 if (__bch_keylist_realloc(&keylist, bkey_u64s(&r[i].b->key)))
1432 goto out_nocoalesce;
1434 make_btree_freeing_key(r[i].b, keylist.top);
1435 bch_keylist_push(&keylist);
1438 bch_btree_insert_node(b, op, &keylist, NULL, NULL);
1439 BUG_ON(!bch_keylist_empty(&keylist));
1441 for (i = 0; i < nodes; i++) {
1442 btree_node_free(r[i].b);
1443 rw_unlock(true, r[i].b);
1445 r[i].b = new_nodes[i];
1448 memmove(r, r + 1, sizeof(r[0]) * (nodes - 1));
1449 r[nodes - 1].b = ERR_PTR(-EINTR);
1451 trace_bcache_btree_gc_coalesce(nodes);
1454 bch_keylist_free(&keylist);
1456 /* Invalidated our iterator */
1461 bch_keylist_free(&keylist);
1463 while ((k = bch_keylist_pop(&keylist)))
1464 if (!bkey_cmp(k, &ZERO_KEY))
1465 atomic_dec(&b->c->prio_blocked);
1467 for (i = 0; i < nodes; i++)
1468 if (!IS_ERR_OR_NULL(new_nodes[i])) {
1469 btree_node_free(new_nodes[i]);
1470 rw_unlock(true, new_nodes[i]);
1475 static int btree_gc_rewrite_node(struct btree *b, struct btree_op *op,
1476 struct btree *replace)
1478 struct keylist keys;
1481 if (btree_check_reserve(b, NULL))
1484 n = btree_node_alloc_replacement(replace, NULL);
1486 /* recheck reserve after allocating replacement node */
1487 if (btree_check_reserve(b, NULL)) {
1493 bch_btree_node_write_sync(n);
1495 bch_keylist_init(&keys);
1496 bch_keylist_add(&keys, &n->key);
1498 make_btree_freeing_key(replace, keys.top);
1499 bch_keylist_push(&keys);
1501 bch_btree_insert_node(b, op, &keys, NULL, NULL);
1502 BUG_ON(!bch_keylist_empty(&keys));
1504 btree_node_free(replace);
1507 /* Invalidated our iterator */
1511 static unsigned btree_gc_count_keys(struct btree *b)
1514 struct btree_iter iter;
1517 for_each_key_filter(&b->keys, k, &iter, bch_ptr_bad)
1518 ret += bkey_u64s(k);
1523 static int btree_gc_recurse(struct btree *b, struct btree_op *op,
1524 struct closure *writes, struct gc_stat *gc)
1527 bool should_rewrite;
1529 struct btree_iter iter;
1530 struct gc_merge_info r[GC_MERGE_NODES];
1531 struct gc_merge_info *i, *last = r + ARRAY_SIZE(r) - 1;
1533 bch_btree_iter_init(&b->keys, &iter, &b->c->gc_done);
1535 for (i = r; i < r + ARRAY_SIZE(r); i++)
1536 i->b = ERR_PTR(-EINTR);
1539 k = bch_btree_iter_next_filter(&iter, &b->keys, bch_ptr_bad);
1541 r->b = bch_btree_node_get(b->c, op, k, b->level - 1,
1544 ret = PTR_ERR(r->b);
1548 r->keys = btree_gc_count_keys(r->b);
1550 ret = btree_gc_coalesce(b, op, gc, r);
1558 if (!IS_ERR(last->b)) {
1559 should_rewrite = btree_gc_mark_node(last->b, gc);
1560 if (should_rewrite) {
1561 ret = btree_gc_rewrite_node(b, op, last->b);
1566 if (last->b->level) {
1567 ret = btree_gc_recurse(last->b, op, writes, gc);
1572 bkey_copy_key(&b->c->gc_done, &last->b->key);
1575 * Must flush leaf nodes before gc ends, since replace
1576 * operations aren't journalled
1578 mutex_lock(&last->b->write_lock);
1579 if (btree_node_dirty(last->b))
1580 bch_btree_node_write(last->b, writes);
1581 mutex_unlock(&last->b->write_lock);
1582 rw_unlock(true, last->b);
1585 memmove(r + 1, r, sizeof(r[0]) * (GC_MERGE_NODES - 1));
1588 if (need_resched()) {
1594 for (i = r; i < r + ARRAY_SIZE(r); i++)
1595 if (!IS_ERR_OR_NULL(i->b)) {
1596 mutex_lock(&i->b->write_lock);
1597 if (btree_node_dirty(i->b))
1598 bch_btree_node_write(i->b, writes);
1599 mutex_unlock(&i->b->write_lock);
1600 rw_unlock(true, i->b);
1606 static int bch_btree_gc_root(struct btree *b, struct btree_op *op,
1607 struct closure *writes, struct gc_stat *gc)
1609 struct btree *n = NULL;
1611 bool should_rewrite;
1613 should_rewrite = btree_gc_mark_node(b, gc);
1614 if (should_rewrite) {
1615 n = btree_node_alloc_replacement(b, NULL);
1617 if (!IS_ERR_OR_NULL(n)) {
1618 bch_btree_node_write_sync(n);
1620 bch_btree_set_root(n);
1628 __bch_btree_mark_key(b->c, b->level + 1, &b->key);
1631 ret = btree_gc_recurse(b, op, writes, gc);
1636 bkey_copy_key(&b->c->gc_done, &b->key);
1641 static void btree_gc_start(struct cache_set *c)
1647 if (!c->gc_mark_valid)
1650 mutex_lock(&c->bucket_lock);
1652 c->gc_mark_valid = 0;
1653 c->gc_done = ZERO_KEY;
1655 for_each_cache(ca, c, i)
1656 for_each_bucket(b, ca) {
1657 b->last_gc = b->gen;
1658 if (!atomic_read(&b->pin)) {
1660 SET_GC_SECTORS_USED(b, 0);
1664 mutex_unlock(&c->bucket_lock);
1667 static void bch_btree_gc_finish(struct cache_set *c)
1673 mutex_lock(&c->bucket_lock);
1676 c->gc_mark_valid = 1;
1679 for (i = 0; i < KEY_PTRS(&c->uuid_bucket); i++)
1680 SET_GC_MARK(PTR_BUCKET(c, &c->uuid_bucket, i),
1683 /* don't reclaim buckets to which writeback keys point */
1685 for (i = 0; i < c->devices_max_used; i++) {
1686 struct bcache_device *d = c->devices[i];
1687 struct cached_dev *dc;
1688 struct keybuf_key *w, *n;
1691 if (!d || UUID_FLASH_ONLY(&c->uuids[i]))
1693 dc = container_of(d, struct cached_dev, disk);
1695 spin_lock(&dc->writeback_keys.lock);
1696 rbtree_postorder_for_each_entry_safe(w, n,
1697 &dc->writeback_keys.keys, node)
1698 for (j = 0; j < KEY_PTRS(&w->key); j++)
1699 SET_GC_MARK(PTR_BUCKET(c, &w->key, j),
1701 spin_unlock(&dc->writeback_keys.lock);
1705 c->avail_nbuckets = 0;
1706 for_each_cache(ca, c, i) {
1709 ca->invalidate_needs_gc = 0;
1711 for (i = ca->sb.d; i < ca->sb.d + ca->sb.keys; i++)
1712 SET_GC_MARK(ca->buckets + *i, GC_MARK_METADATA);
1714 for (i = ca->prio_buckets;
1715 i < ca->prio_buckets + prio_buckets(ca) * 2; i++)
1716 SET_GC_MARK(ca->buckets + *i, GC_MARK_METADATA);
1718 for_each_bucket(b, ca) {
1719 c->need_gc = max(c->need_gc, bucket_gc_gen(b));
1721 if (atomic_read(&b->pin))
1724 BUG_ON(!GC_MARK(b) && GC_SECTORS_USED(b));
1726 if (!GC_MARK(b) || GC_MARK(b) == GC_MARK_RECLAIMABLE)
1727 c->avail_nbuckets++;
1731 mutex_unlock(&c->bucket_lock);
1734 static void bch_btree_gc(struct cache_set *c)
1737 struct gc_stat stats;
1738 struct closure writes;
1740 uint64_t start_time = local_clock();
1742 trace_bcache_gc_start(c);
1744 memset(&stats, 0, sizeof(struct gc_stat));
1745 closure_init_stack(&writes);
1746 bch_btree_op_init(&op, SHRT_MAX);
1750 /* if CACHE_SET_IO_DISABLE set, gc thread should stop too */
1752 ret = btree_root(gc_root, c, &op, &writes, &stats);
1753 closure_sync(&writes);
1756 if (ret && ret != -EAGAIN)
1757 pr_warn("gc failed!");
1758 } while (ret && !test_bit(CACHE_SET_IO_DISABLE, &c->flags));
1760 bch_btree_gc_finish(c);
1761 wake_up_allocators(c);
1763 bch_time_stats_update(&c->btree_gc_time, start_time);
1765 stats.key_bytes *= sizeof(uint64_t);
1767 bch_update_bucket_in_use(c, &stats);
1768 memcpy(&c->gc_stats, &stats, sizeof(struct gc_stat));
1770 trace_bcache_gc_end(c);
1775 static bool gc_should_run(struct cache_set *c)
1780 for_each_cache(ca, c, i)
1781 if (ca->invalidate_needs_gc)
1784 if (atomic_read(&c->sectors_to_gc) < 0)
1790 static int bch_gc_thread(void *arg)
1792 struct cache_set *c = arg;
1795 wait_event_interruptible(c->gc_wait,
1796 kthread_should_stop() ||
1797 test_bit(CACHE_SET_IO_DISABLE, &c->flags) ||
1800 if (kthread_should_stop() ||
1801 test_bit(CACHE_SET_IO_DISABLE, &c->flags))
1808 wait_for_kthread_stop();
1812 int bch_gc_thread_start(struct cache_set *c)
1814 c->gc_thread = kthread_run(bch_gc_thread, c, "bcache_gc");
1815 return PTR_ERR_OR_ZERO(c->gc_thread);
1818 /* Initial partial gc */
1820 static int bch_btree_check_recurse(struct btree *b, struct btree_op *op)
1823 struct bkey *k, *p = NULL;
1824 struct btree_iter iter;
1826 for_each_key_filter(&b->keys, k, &iter, bch_ptr_invalid)
1827 bch_initial_mark_key(b->c, b->level, k);
1829 bch_initial_mark_key(b->c, b->level + 1, &b->key);
1832 bch_btree_iter_init(&b->keys, &iter, NULL);
1835 k = bch_btree_iter_next_filter(&iter, &b->keys,
1838 btree_node_prefetch(b, k);
1841 ret = btree(check_recurse, p, b, op);
1844 } while (p && !ret);
1850 int bch_btree_check(struct cache_set *c)
1854 bch_btree_op_init(&op, SHRT_MAX);
1856 return btree_root(check_recurse, c, &op);
1859 void bch_initial_gc_finish(struct cache_set *c)
1865 bch_btree_gc_finish(c);
1867 mutex_lock(&c->bucket_lock);
1870 * We need to put some unused buckets directly on the prio freelist in
1871 * order to get the allocator thread started - it needs freed buckets in
1872 * order to rewrite the prios and gens, and it needs to rewrite prios
1873 * and gens in order to free buckets.
1875 * This is only safe for buckets that have no live data in them, which
1876 * there should always be some of.
1878 for_each_cache(ca, c, i) {
1879 for_each_bucket(b, ca) {
1880 if (fifo_full(&ca->free[RESERVE_PRIO]) &&
1881 fifo_full(&ca->free[RESERVE_BTREE]))
1884 if (bch_can_invalidate_bucket(ca, b) &&
1886 __bch_invalidate_one_bucket(ca, b);
1887 if (!fifo_push(&ca->free[RESERVE_PRIO],
1889 fifo_push(&ca->free[RESERVE_BTREE],
1895 mutex_unlock(&c->bucket_lock);
1898 /* Btree insertion */
1900 static bool btree_insert_key(struct btree *b, struct bkey *k,
1901 struct bkey *replace_key)
1905 BUG_ON(bkey_cmp(k, &b->key) > 0);
1907 status = bch_btree_insert_key(&b->keys, k, replace_key);
1908 if (status != BTREE_INSERT_STATUS_NO_INSERT) {
1909 bch_check_keys(&b->keys, "%u for %s", status,
1910 replace_key ? "replace" : "insert");
1912 trace_bcache_btree_insert_key(b, k, replace_key != NULL,
1919 static size_t insert_u64s_remaining(struct btree *b)
1921 long ret = bch_btree_keys_u64s_remaining(&b->keys);
1924 * Might land in the middle of an existing extent and have to split it
1926 if (b->keys.ops->is_extents)
1927 ret -= KEY_MAX_U64S;
1929 return max(ret, 0L);
1932 static bool bch_btree_insert_keys(struct btree *b, struct btree_op *op,
1933 struct keylist *insert_keys,
1934 struct bkey *replace_key)
1937 int oldsize = bch_count_data(&b->keys);
1939 while (!bch_keylist_empty(insert_keys)) {
1940 struct bkey *k = insert_keys->keys;
1942 if (bkey_u64s(k) > insert_u64s_remaining(b))
1945 if (bkey_cmp(k, &b->key) <= 0) {
1949 ret |= btree_insert_key(b, k, replace_key);
1950 bch_keylist_pop_front(insert_keys);
1951 } else if (bkey_cmp(&START_KEY(k), &b->key) < 0) {
1952 BKEY_PADDED(key) temp;
1953 bkey_copy(&temp.key, insert_keys->keys);
1955 bch_cut_back(&b->key, &temp.key);
1956 bch_cut_front(&b->key, insert_keys->keys);
1958 ret |= btree_insert_key(b, &temp.key, replace_key);
1966 op->insert_collision = true;
1968 BUG_ON(!bch_keylist_empty(insert_keys) && b->level);
1970 BUG_ON(bch_count_data(&b->keys) < oldsize);
1974 static int btree_split(struct btree *b, struct btree_op *op,
1975 struct keylist *insert_keys,
1976 struct bkey *replace_key)
1979 struct btree *n1, *n2 = NULL, *n3 = NULL;
1980 uint64_t start_time = local_clock();
1982 struct keylist parent_keys;
1984 closure_init_stack(&cl);
1985 bch_keylist_init(&parent_keys);
1987 if (btree_check_reserve(b, op)) {
1991 WARN(1, "insufficient reserve for split\n");
1994 n1 = btree_node_alloc_replacement(b, op);
1998 split = set_blocks(btree_bset_first(n1),
1999 block_bytes(n1->c)) > (btree_blocks(b) * 4) / 5;
2004 trace_bcache_btree_node_split(b, btree_bset_first(n1)->keys);
2006 n2 = bch_btree_node_alloc(b->c, op, b->level, b->parent);
2011 n3 = bch_btree_node_alloc(b->c, op, b->level + 1, NULL);
2016 mutex_lock(&n1->write_lock);
2017 mutex_lock(&n2->write_lock);
2019 bch_btree_insert_keys(n1, op, insert_keys, replace_key);
2022 * Has to be a linear search because we don't have an auxiliary
2026 while (keys < (btree_bset_first(n1)->keys * 3) / 5)
2027 keys += bkey_u64s(bset_bkey_idx(btree_bset_first(n1),
2030 bkey_copy_key(&n1->key,
2031 bset_bkey_idx(btree_bset_first(n1), keys));
2032 keys += bkey_u64s(bset_bkey_idx(btree_bset_first(n1), keys));
2034 btree_bset_first(n2)->keys = btree_bset_first(n1)->keys - keys;
2035 btree_bset_first(n1)->keys = keys;
2037 memcpy(btree_bset_first(n2)->start,
2038 bset_bkey_last(btree_bset_first(n1)),
2039 btree_bset_first(n2)->keys * sizeof(uint64_t));
2041 bkey_copy_key(&n2->key, &b->key);
2043 bch_keylist_add(&parent_keys, &n2->key);
2044 bch_btree_node_write(n2, &cl);
2045 mutex_unlock(&n2->write_lock);
2046 rw_unlock(true, n2);
2048 trace_bcache_btree_node_compact(b, btree_bset_first(n1)->keys);
2050 mutex_lock(&n1->write_lock);
2051 bch_btree_insert_keys(n1, op, insert_keys, replace_key);
2054 bch_keylist_add(&parent_keys, &n1->key);
2055 bch_btree_node_write(n1, &cl);
2056 mutex_unlock(&n1->write_lock);
2059 /* Depth increases, make a new root */
2060 mutex_lock(&n3->write_lock);
2061 bkey_copy_key(&n3->key, &MAX_KEY);
2062 bch_btree_insert_keys(n3, op, &parent_keys, NULL);
2063 bch_btree_node_write(n3, &cl);
2064 mutex_unlock(&n3->write_lock);
2067 bch_btree_set_root(n3);
2068 rw_unlock(true, n3);
2069 } else if (!b->parent) {
2070 /* Root filled up but didn't need to be split */
2072 bch_btree_set_root(n1);
2074 /* Split a non root node */
2076 make_btree_freeing_key(b, parent_keys.top);
2077 bch_keylist_push(&parent_keys);
2079 bch_btree_insert_node(b->parent, op, &parent_keys, NULL, NULL);
2080 BUG_ON(!bch_keylist_empty(&parent_keys));
2084 rw_unlock(true, n1);
2086 bch_time_stats_update(&b->c->btree_split_time, start_time);
2090 bkey_put(b->c, &n2->key);
2091 btree_node_free(n2);
2092 rw_unlock(true, n2);
2094 bkey_put(b->c, &n1->key);
2095 btree_node_free(n1);
2096 rw_unlock(true, n1);
2098 WARN(1, "bcache: btree split failed (level %u)", b->level);
2100 if (n3 == ERR_PTR(-EAGAIN) ||
2101 n2 == ERR_PTR(-EAGAIN) ||
2102 n1 == ERR_PTR(-EAGAIN))
2108 static int bch_btree_insert_node(struct btree *b, struct btree_op *op,
2109 struct keylist *insert_keys,
2110 atomic_t *journal_ref,
2111 struct bkey *replace_key)
2115 BUG_ON(b->level && replace_key);
2117 closure_init_stack(&cl);
2119 mutex_lock(&b->write_lock);
2121 if (write_block(b) != btree_bset_last(b) &&
2122 b->keys.last_set_unwritten)
2123 bch_btree_init_next(b); /* just wrote a set */
2125 if (bch_keylist_nkeys(insert_keys) > insert_u64s_remaining(b)) {
2126 mutex_unlock(&b->write_lock);
2130 BUG_ON(write_block(b) != btree_bset_last(b));
2132 if (bch_btree_insert_keys(b, op, insert_keys, replace_key)) {
2134 bch_btree_leaf_dirty(b, journal_ref);
2136 bch_btree_node_write(b, &cl);
2139 mutex_unlock(&b->write_lock);
2141 /* wait for btree node write if necessary, after unlock */
2146 if (current->bio_list) {
2147 op->lock = b->c->root->level + 1;
2149 } else if (op->lock <= b->c->root->level) {
2150 op->lock = b->c->root->level + 1;
2153 /* Invalidated all iterators */
2154 int ret = btree_split(b, op, insert_keys, replace_key);
2156 if (bch_keylist_empty(insert_keys))
2164 int bch_btree_insert_check_key(struct btree *b, struct btree_op *op,
2165 struct bkey *check_key)
2168 uint64_t btree_ptr = b->key.ptr[0];
2169 unsigned long seq = b->seq;
2170 struct keylist insert;
2171 bool upgrade = op->lock == -1;
2173 bch_keylist_init(&insert);
2176 rw_unlock(false, b);
2177 rw_lock(true, b, b->level);
2179 if (b->key.ptr[0] != btree_ptr ||
2180 b->seq != seq + 1) {
2181 op->lock = b->level;
2186 SET_KEY_PTRS(check_key, 1);
2187 get_random_bytes(&check_key->ptr[0], sizeof(uint64_t));
2189 SET_PTR_DEV(check_key, 0, PTR_CHECK_DEV);
2191 bch_keylist_add(&insert, check_key);
2193 ret = bch_btree_insert_node(b, op, &insert, NULL, NULL);
2195 BUG_ON(!ret && !bch_keylist_empty(&insert));
2198 downgrade_write(&b->lock);
2202 struct btree_insert_op {
2204 struct keylist *keys;
2205 atomic_t *journal_ref;
2206 struct bkey *replace_key;
2209 static int btree_insert_fn(struct btree_op *b_op, struct btree *b)
2211 struct btree_insert_op *op = container_of(b_op,
2212 struct btree_insert_op, op);
2214 int ret = bch_btree_insert_node(b, &op->op, op->keys,
2215 op->journal_ref, op->replace_key);
2216 if (ret && !bch_keylist_empty(op->keys))
2222 int bch_btree_insert(struct cache_set *c, struct keylist *keys,
2223 atomic_t *journal_ref, struct bkey *replace_key)
2225 struct btree_insert_op op;
2228 BUG_ON(current->bio_list);
2229 BUG_ON(bch_keylist_empty(keys));
2231 bch_btree_op_init(&op.op, 0);
2233 op.journal_ref = journal_ref;
2234 op.replace_key = replace_key;
2236 while (!ret && !bch_keylist_empty(keys)) {
2238 ret = bch_btree_map_leaf_nodes(&op.op, c,
2239 &START_KEY(keys->keys),
2246 pr_err("error %i", ret);
2248 while ((k = bch_keylist_pop(keys)))
2250 } else if (op.op.insert_collision)
2256 void bch_btree_set_root(struct btree *b)
2261 closure_init_stack(&cl);
2263 trace_bcache_btree_set_root(b);
2265 BUG_ON(!b->written);
2267 for (i = 0; i < KEY_PTRS(&b->key); i++)
2268 BUG_ON(PTR_BUCKET(b->c, &b->key, i)->prio != BTREE_PRIO);
2270 mutex_lock(&b->c->bucket_lock);
2271 list_del_init(&b->list);
2272 mutex_unlock(&b->c->bucket_lock);
2276 bch_journal_meta(b->c, &cl);
2280 /* Map across nodes or keys */
2282 static int bch_btree_map_nodes_recurse(struct btree *b, struct btree_op *op,
2284 btree_map_nodes_fn *fn, int flags)
2286 int ret = MAP_CONTINUE;
2290 struct btree_iter iter;
2292 bch_btree_iter_init(&b->keys, &iter, from);
2294 while ((k = bch_btree_iter_next_filter(&iter, &b->keys,
2296 ret = btree(map_nodes_recurse, k, b,
2297 op, from, fn, flags);
2300 if (ret != MAP_CONTINUE)
2305 if (!b->level || flags == MAP_ALL_NODES)
2311 int __bch_btree_map_nodes(struct btree_op *op, struct cache_set *c,
2312 struct bkey *from, btree_map_nodes_fn *fn, int flags)
2314 return btree_root(map_nodes_recurse, c, op, from, fn, flags);
2317 static int bch_btree_map_keys_recurse(struct btree *b, struct btree_op *op,
2318 struct bkey *from, btree_map_keys_fn *fn,
2321 int ret = MAP_CONTINUE;
2323 struct btree_iter iter;
2325 bch_btree_iter_init(&b->keys, &iter, from);
2327 while ((k = bch_btree_iter_next_filter(&iter, &b->keys, bch_ptr_bad))) {
2330 : btree(map_keys_recurse, k, b, op, from, fn, flags);
2333 if (ret != MAP_CONTINUE)
2337 if (!b->level && (flags & MAP_END_KEY))
2338 ret = fn(op, b, &KEY(KEY_INODE(&b->key),
2339 KEY_OFFSET(&b->key), 0));
2344 int bch_btree_map_keys(struct btree_op *op, struct cache_set *c,
2345 struct bkey *from, btree_map_keys_fn *fn, int flags)
2347 return btree_root(map_keys_recurse, c, op, from, fn, flags);
2352 static inline int keybuf_cmp(struct keybuf_key *l, struct keybuf_key *r)
2354 /* Overlapping keys compare equal */
2355 if (bkey_cmp(&l->key, &START_KEY(&r->key)) <= 0)
2357 if (bkey_cmp(&START_KEY(&l->key), &r->key) >= 0)
2362 static inline int keybuf_nonoverlapping_cmp(struct keybuf_key *l,
2363 struct keybuf_key *r)
2365 return clamp_t(int64_t, bkey_cmp(&l->key, &r->key), -1, 1);
2373 keybuf_pred_fn *pred;
2376 static int refill_keybuf_fn(struct btree_op *op, struct btree *b,
2379 struct refill *refill = container_of(op, struct refill, op);
2380 struct keybuf *buf = refill->buf;
2381 int ret = MAP_CONTINUE;
2383 if (bkey_cmp(k, refill->end) >= 0) {
2388 if (!KEY_SIZE(k)) /* end key */
2391 if (refill->pred(buf, k)) {
2392 struct keybuf_key *w;
2394 spin_lock(&buf->lock);
2396 w = array_alloc(&buf->freelist);
2398 spin_unlock(&buf->lock);
2403 bkey_copy(&w->key, k);
2405 if (RB_INSERT(&buf->keys, w, node, keybuf_cmp))
2406 array_free(&buf->freelist, w);
2410 if (array_freelist_empty(&buf->freelist))
2413 spin_unlock(&buf->lock);
2416 buf->last_scanned = *k;
2420 void bch_refill_keybuf(struct cache_set *c, struct keybuf *buf,
2421 struct bkey *end, keybuf_pred_fn *pred)
2423 struct bkey start = buf->last_scanned;
2424 struct refill refill;
2428 bch_btree_op_init(&refill.op, -1);
2429 refill.nr_found = 0;
2434 bch_btree_map_keys(&refill.op, c, &buf->last_scanned,
2435 refill_keybuf_fn, MAP_END_KEY);
2437 trace_bcache_keyscan(refill.nr_found,
2438 KEY_INODE(&start), KEY_OFFSET(&start),
2439 KEY_INODE(&buf->last_scanned),
2440 KEY_OFFSET(&buf->last_scanned));
2442 spin_lock(&buf->lock);
2444 if (!RB_EMPTY_ROOT(&buf->keys)) {
2445 struct keybuf_key *w;
2446 w = RB_FIRST(&buf->keys, struct keybuf_key, node);
2447 buf->start = START_KEY(&w->key);
2449 w = RB_LAST(&buf->keys, struct keybuf_key, node);
2452 buf->start = MAX_KEY;
2456 spin_unlock(&buf->lock);
2459 static void __bch_keybuf_del(struct keybuf *buf, struct keybuf_key *w)
2461 rb_erase(&w->node, &buf->keys);
2462 array_free(&buf->freelist, w);
2465 void bch_keybuf_del(struct keybuf *buf, struct keybuf_key *w)
2467 spin_lock(&buf->lock);
2468 __bch_keybuf_del(buf, w);
2469 spin_unlock(&buf->lock);
2472 bool bch_keybuf_check_overlapping(struct keybuf *buf, struct bkey *start,
2476 struct keybuf_key *p, *w, s;
2479 if (bkey_cmp(end, &buf->start) <= 0 ||
2480 bkey_cmp(start, &buf->end) >= 0)
2483 spin_lock(&buf->lock);
2484 w = RB_GREATER(&buf->keys, s, node, keybuf_nonoverlapping_cmp);
2486 while (w && bkey_cmp(&START_KEY(&w->key), end) < 0) {
2488 w = RB_NEXT(w, node);
2493 __bch_keybuf_del(buf, p);
2496 spin_unlock(&buf->lock);
2500 struct keybuf_key *bch_keybuf_next(struct keybuf *buf)
2502 struct keybuf_key *w;
2503 spin_lock(&buf->lock);
2505 w = RB_FIRST(&buf->keys, struct keybuf_key, node);
2507 while (w && w->private)
2508 w = RB_NEXT(w, node);
2511 w->private = ERR_PTR(-EINTR);
2513 spin_unlock(&buf->lock);
2517 struct keybuf_key *bch_keybuf_next_rescan(struct cache_set *c,
2520 keybuf_pred_fn *pred)
2522 struct keybuf_key *ret;
2525 ret = bch_keybuf_next(buf);
2529 if (bkey_cmp(&buf->last_scanned, end) >= 0) {
2530 pr_debug("scan finished");
2534 bch_refill_keybuf(c, buf, end, pred);
2540 void bch_keybuf_init(struct keybuf *buf)
2542 buf->last_scanned = MAX_KEY;
2543 buf->keys = RB_ROOT;
2545 spin_lock_init(&buf->lock);
2546 array_allocator_init(&buf->freelist);