[linux-block.git] / fs / bcachefs / btree_locking.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _BCACHEFS_BTREE_LOCKING_H
#define _BCACHEFS_BTREE_LOCKING_H

/*
 * Only for internal btree use:
 *
 * The btree iterator tracks what locks it wants to take, and what locks it
 * currently has - here we have wrappers for locking/unlocking btree nodes and
 * updating the iterator state
 */

#include "btree_iter.h"
#include "six.h"

/* matches six lock types */
enum btree_node_locked_type {
	BTREE_NODE_UNLOCKED		= -1,
	BTREE_NODE_READ_LOCKED		= SIX_LOCK_read,
	BTREE_NODE_INTENT_LOCKED	= SIX_LOCK_intent,
};

static inline int btree_node_locked_type(struct btree_iter *iter,
					 unsigned level)
{
	/*
	 * We're relying on the fact that if nodes_intent_locked is set
	 * nodes_locked must be set as well, so that we can compute without
	 * branches:
	 */
	return BTREE_NODE_UNLOCKED +
		((iter->nodes_locked >> level) & 1) +
		((iter->nodes_intent_locked >> level) & 1);
}

static inline bool btree_node_intent_locked(struct btree_iter *iter,
					    unsigned level)
{
	return btree_node_locked_type(iter, level) == BTREE_NODE_INTENT_LOCKED;
}

static inline bool btree_node_read_locked(struct btree_iter *iter,
					  unsigned level)
{
	return btree_node_locked_type(iter, level) == BTREE_NODE_READ_LOCKED;
}

static inline bool btree_node_locked(struct btree_iter *iter, unsigned level)
{
	return iter->nodes_locked & (1 << level);
}

static inline void mark_btree_node_unlocked(struct btree_iter *iter,
					    unsigned level)
{
	iter->nodes_locked &= ~(1 << level);
	iter->nodes_intent_locked &= ~(1 << level);
}

static inline void mark_btree_node_locked(struct btree_iter *iter,
					  unsigned level,
					  enum six_lock_type type)
{
	/* relying on this to avoid a branch */
	BUILD_BUG_ON(SIX_LOCK_read   != 0);
	BUILD_BUG_ON(SIX_LOCK_intent != 1);

	iter->nodes_locked |= 1 << level;
	iter->nodes_intent_locked |= type << level;
}

static inline void mark_btree_node_intent_locked(struct btree_iter *iter,
						 unsigned level)
{
	mark_btree_node_locked(iter, level, SIX_LOCK_intent);
}

static inline enum six_lock_type __btree_lock_want(struct btree_iter *iter, int level)
{
	return level < iter->locks_want
		? SIX_LOCK_intent
		: SIX_LOCK_read;
}

static inline enum btree_node_locked_type
btree_lock_want(struct btree_iter *iter, int level)
{
	if (level < iter->level)
		return BTREE_NODE_UNLOCKED;
	if (level < iter->locks_want)
		return BTREE_NODE_INTENT_LOCKED;
	if (level == iter->level)
		return BTREE_NODE_READ_LOCKED;
	return BTREE_NODE_UNLOCKED;
}

static inline void btree_node_unlock(struct btree_iter *iter, unsigned level)
{
	int lock_type = btree_node_locked_type(iter, level);

	EBUG_ON(level >= BTREE_MAX_DEPTH);

	if (lock_type != BTREE_NODE_UNLOCKED)
		six_unlock_type(&iter->l[level].b->c.lock, lock_type);
	mark_btree_node_unlocked(iter, level);
}

static inline void __bch2_btree_iter_unlock(struct btree_iter *iter)
{
	btree_iter_set_dirty(iter, BTREE_ITER_NEED_RELOCK);

	while (iter->nodes_locked)
		btree_node_unlock(iter, __ffs(iter->nodes_locked));
}

static inline enum bch_time_stats lock_to_time_stat(enum six_lock_type type)
{
	switch (type) {
	case SIX_LOCK_read:
		return BCH_TIME_btree_lock_contended_read;
	case SIX_LOCK_intent:
		return BCH_TIME_btree_lock_contended_intent;
	case SIX_LOCK_write:
		return BCH_TIME_btree_lock_contended_write;
	default:
		BUG();
	}
}

/*
 * wrapper around six locks that just traces lock contended time
 */
static inline void __btree_node_lock_type(struct bch_fs *c, struct btree *b,
					  enum six_lock_type type)
{
	u64 start_time = local_clock();

	six_lock_type(&b->c.lock, type, NULL, NULL);
	bch2_time_stats_update(&c->times[lock_to_time_stat(type)], start_time);
}

static inline void btree_node_lock_type(struct bch_fs *c, struct btree *b,
					enum six_lock_type type)
{
	if (!six_trylock_type(&b->c.lock, type))
		__btree_node_lock_type(c, b, type);
}

/*
 * Lock a btree node if we already have it locked on one of our linked
 * iterators:
 */
static inline bool btree_node_lock_increment(struct btree_trans *trans,
					     struct btree *b, unsigned level,
					     enum btree_node_locked_type want)
{
	struct btree_iter *iter;

	trans_for_each_iter(trans, iter)
		if (iter->l[level].b == b &&
		    btree_node_locked_type(iter, level) >= want) {
			six_lock_increment(&b->c.lock, want);
			return true;
		}

	return false;
}

bool __bch2_btree_node_lock(struct btree *, struct bpos, unsigned,
			    struct btree_iter *, enum six_lock_type,
			    six_lock_should_sleep_fn, void *,
			    unsigned long);

static inline bool btree_node_lock(struct btree *b,
			struct bpos pos, unsigned level,
			struct btree_iter *iter,
			enum six_lock_type type,
			six_lock_should_sleep_fn should_sleep_fn, void *p,
			unsigned long ip)
{
	struct btree_trans *trans = iter->trans;

	EBUG_ON(level >= BTREE_MAX_DEPTH);
	EBUG_ON(!(trans->iters_linked & (1ULL << iter->idx)));

	return likely(six_trylock_type(&b->c.lock, type)) ||
		btree_node_lock_increment(trans, b, level, type) ||
		__bch2_btree_node_lock(b, pos, level, iter, type,
				       should_sleep_fn, p, ip);
}

bool __bch2_btree_node_relock(struct btree_iter *, unsigned);

static inline bool bch2_btree_node_relock(struct btree_iter *iter,
					  unsigned level)
{
	EBUG_ON(btree_node_locked(iter, level) &&
		btree_node_locked_type(iter, level) !=
		__btree_lock_want(iter, level));

	return likely(btree_node_locked(iter, level)) ||
		__bch2_btree_node_relock(iter, level);
}

/*
 * Updates the saved lock sequence number, so that bch2_btree_node_relock() will
 * succeed:
 */
static inline void
bch2_btree_node_unlock_write_inlined(struct btree *b, struct btree_iter *iter)
{
	struct btree_iter *linked;

	EBUG_ON(iter->l[b->c.level].b != b);
	EBUG_ON(iter->l[b->c.level].lock_seq + 1 != b->c.lock.state.seq);

	trans_for_each_iter_with_node(iter->trans, b, linked)
		linked->l[b->c.level].lock_seq += 2;

	six_unlock_write(&b->c.lock);
}

void bch2_btree_node_unlock_write(struct btree *, struct btree_iter *);

void __bch2_btree_node_lock_write(struct btree *, struct btree_iter *);

static inline void bch2_btree_node_lock_write(struct btree *b, struct btree_iter *iter)
{
	EBUG_ON(iter->l[b->c.level].b != b);
	EBUG_ON(iter->l[b->c.level].lock_seq != b->c.lock.state.seq);

	if (unlikely(!six_trylock_write(&b->c.lock)))
		__bch2_btree_node_lock_write(b, iter);
}

#endif /* _BCACHEFS_BTREE_LOCKING_H */
Commit	Line	Data
1c6fdbd8 KO	1	/* SPDX-License-Identifier: GPL-2.0 */
	2	#ifndef _BCACHEFS_BTREE_LOCKING_H
	3	#define _BCACHEFS_BTREE_LOCKING_H
	4
	5	/*
	6	* Only for internal btree use:
	7	*
	8	* The btree iterator tracks what locks it wants to take, and what locks it
	9	* currently has - here we have wrappers for locking/unlocking btree nodes and
	10	* updating the iterator state
	11	*/
	12
	13	#include "btree_iter.h"
1c6fdbd8 KO	14	#include "six.h"
	15
	16	/* matches six lock types */
	17	enum btree_node_locked_type {
	18	BTREE_NODE_UNLOCKED = -1,
	19	BTREE_NODE_READ_LOCKED = SIX_LOCK_read,
	20	BTREE_NODE_INTENT_LOCKED = SIX_LOCK_intent,
	21	};
	22
	23	static inline int btree_node_locked_type(struct btree_iter *iter,
	24	unsigned level)
	25	{
	26	/*
	27	* We're relying on the fact that if nodes_intent_locked is set
	28	* nodes_locked must be set as well, so that we can compute without
	29	* branches:
	30	*/
	31	return BTREE_NODE_UNLOCKED +
	32	((iter->nodes_locked >> level) & 1) +
	33	((iter->nodes_intent_locked >> level) & 1);
	34	}
	35
	36	static inline bool btree_node_intent_locked(struct btree_iter *iter,
	37	unsigned level)
	38	{
	39	return btree_node_locked_type(iter, level) == BTREE_NODE_INTENT_LOCKED;
	40	}
	41
	42	static inline bool btree_node_read_locked(struct btree_iter *iter,
	43	unsigned level)
	44	{
	45	return btree_node_locked_type(iter, level) == BTREE_NODE_READ_LOCKED;
	46	}
	47
	48	static inline bool btree_node_locked(struct btree_iter *iter, unsigned level)
	49	{
	50	return iter->nodes_locked & (1 << level);
	51	}
	52
	53	static inline void mark_btree_node_unlocked(struct btree_iter *iter,
	54	unsigned level)
	55	{
	56	iter->nodes_locked &= ~(1 << level);
	57	iter->nodes_intent_locked &= ~(1 << level);
	58	}
	59
	60	static inline void mark_btree_node_locked(struct btree_iter *iter,
	61	unsigned level,
	62	enum six_lock_type type)
	63	{
	64	/* relying on this to avoid a branch */
	65	BUILD_BUG_ON(SIX_LOCK_read != 0);
	66	BUILD_BUG_ON(SIX_LOCK_intent != 1);
	67
	68	iter->nodes_locked \|= 1 << level;
	69	iter->nodes_intent_locked \|= type << level;
	70	}
	71
	72	static inline void mark_btree_node_intent_locked(struct btree_iter *iter,
	73	unsigned level)
	74	{
	75	mark_btree_node_locked(iter, level, SIX_LOCK_intent);
	76	}
	77
78	static inline enum six_lock_type __btree_lock_want(struct btree_iter *iter, int level)
79	{
80	return level < iter->locks_want
81	? SIX_LOCK_intent
82	: SIX_LOCK_read;
83	}
84
85	static inline enum btree_node_locked_type
86	btree_lock_want(struct btree_iter *iter, int level)
87	{
88	if (level < iter->level)
89	return BTREE_NODE_UNLOCKED;
90	if (level < iter->locks_want)
91	return BTREE_NODE_INTENT_LOCKED;
92	if (level == iter->level)
93	return BTREE_NODE_READ_LOCKED;
94	return BTREE_NODE_UNLOCKED;
95	}
96
5c1d808a	97	static inline void btree_node_unlock(struct btree_iter *iter, unsigned level)
1c6fdbd8 KO	98	{
	99	int lock_type = btree_node_locked_type(iter, level);
	100
	101	EBUG_ON(level >= BTREE_MAX_DEPTH);
	102
	103	if (lock_type != BTREE_NODE_UNLOCKED)
c43a6ef9	104	six_unlock_type(&iter->l[level].b->c.lock, lock_type);
1c6fdbd8 KO	105	mark_btree_node_unlocked(iter, level);
	106	}
	107
	108	static inline void __bch2_btree_iter_unlock(struct btree_iter *iter)
	109	{
	110	btree_iter_set_dirty(iter, BTREE_ITER_NEED_RELOCK);
	111
	112	while (iter->nodes_locked)
	113	btree_node_unlock(iter, __ffs(iter->nodes_locked));
	114	}
	115
	116	static inline enum bch_time_stats lock_to_time_stat(enum six_lock_type type)
	117	{
	118	switch (type) {
	119	case SIX_LOCK_read:
	120	return BCH_TIME_btree_lock_contended_read;
	121	case SIX_LOCK_intent:
	122	return BCH_TIME_btree_lock_contended_intent;
	123	case SIX_LOCK_write:
	124	return BCH_TIME_btree_lock_contended_write;
	125	default:
	126	BUG();
	127	}
	128	}
	129
	130	/*
	131	* wrapper around six locks that just traces lock contended time
	132	*/
	133	static inline void __btree_node_lock_type(struct bch_fs c, struct btree b,
	134	enum six_lock_type type)
	135	{
	136	u64 start_time = local_clock();
	137
c43a6ef9	138	six_lock_type(&b->c.lock, type, NULL, NULL);
1c6fdbd8 KO	139	bch2_time_stats_update(&c->times[lock_to_time_stat(type)], start_time);
	140	}
	141
	142	static inline void btree_node_lock_type(struct bch_fs c, struct btree b,
	143	enum six_lock_type type)
	144	{
c43a6ef9	145	if (!six_trylock_type(&b->c.lock, type))
1c6fdbd8 KO	146	__btree_node_lock_type(c, b, type);
	147	}
	148
647d7b60 KO	149	/*
	150	* Lock a btree node if we already have it locked on one of our linked
	151	* iterators:
	152	*/
515282ac	153	static inline bool btree_node_lock_increment(struct btree_trans *trans,
647d7b60 KO	154	struct btree *b, unsigned level,
	155	enum btree_node_locked_type want)
	156	{
515282ac	157	struct btree_iter *iter;
647d7b60	158
515282ac KO	159	trans_for_each_iter(trans, iter)
	160	if (iter->l[level].b == b &&
	161	btree_node_locked_type(iter, level) >= want) {
c43a6ef9	162	six_lock_increment(&b->c.lock, want);
647d7b60 KO	163	return true;
	164	}
	165
	166	return false;
	167	}
	168
1c6fdbd8	169	bool __bch2_btree_node_lock(struct btree *, struct bpos, unsigned,
bd2bb273	170	struct btree_iter *, enum six_lock_type,
a301dc38 KO	171	six_lock_should_sleep_fn, void *,
a301dc38 KO	172	unsigned long);
1c6fdbd8	173
bd2bb273 KO	174	static inline bool btree_node_lock(struct btree *b,
	175	struct bpos pos, unsigned level,
	176	struct btree_iter *iter,
	177	enum six_lock_type type,
a301dc38 KO	178	six_lock_should_sleep_fn should_sleep_fn, void *p,
a301dc38 KO	179	unsigned long ip)
1c6fdbd8	180	{
515282ac	181	struct btree_trans *trans = iter->trans;
495aabed	182
1c6fdbd8	183	EBUG_ON(level >= BTREE_MAX_DEPTH);
bd2bb273 KO	184	EBUG_ON(!(trans->iters_linked & (1ULL << iter->idx)));
bd2bb273 KO	185
acb3b26e	186	return likely(six_trylock_type(&b->c.lock, type)) \|\|
515282ac	187	btree_node_lock_increment(trans, b, level, type) \|\|
bd2bb273	188	__bch2_btree_node_lock(b, pos, level, iter, type,
a301dc38	189	should_sleep_fn, p, ip);
1c6fdbd8 KO	190	}
	191
	192	bool __bch2_btree_node_relock(struct btree_iter *, unsigned);
	193
	194	static inline bool bch2_btree_node_relock(struct btree_iter *iter,
	195	unsigned level)
	196	{
	197	EBUG_ON(btree_node_locked(iter, level) &&
	198	btree_node_locked_type(iter, level) !=
	199	__btree_lock_want(iter, level));
	200
	201	return likely(btree_node_locked(iter, level)) \|\|
	202	__bch2_btree_node_relock(iter, level);
	203	}
	204
b7ba66c8 KO	205	/*
	206	* Updates the saved lock sequence number, so that bch2_btree_node_relock() will
	207	* succeed:
	208	*/
	209	static inline void
	210	bch2_btree_node_unlock_write_inlined(struct btree b, struct btree_iter iter)
	211	{
	212	struct btree_iter *linked;
	213
	214	EBUG_ON(iter->l[b->c.level].b != b);
	215	EBUG_ON(iter->l[b->c.level].lock_seq + 1 != b->c.lock.state.seq);
	216
	217	trans_for_each_iter_with_node(iter->trans, b, linked)
	218	linked->l[b->c.level].lock_seq += 2;
	219
	220	six_unlock_write(&b->c.lock);
	221	}
	222
1c6fdbd8 KO	223	void bch2_btree_node_unlock_write(struct btree , struct btree_iter );
	224
	225	void __bch2_btree_node_lock_write(struct btree , struct btree_iter );
	226
	227	static inline void bch2_btree_node_lock_write(struct btree b, struct btree_iter iter)
	228	{
c43a6ef9 KO	229	EBUG_ON(iter->l[b->c.level].b != b);
c43a6ef9 KO	230	EBUG_ON(iter->l[b->c.level].lock_seq != b->c.lock.state.seq);
1c6fdbd8	231
fdfab313	232	if (unlikely(!six_trylock_write(&b->c.lock)))
1c6fdbd8 KO	233	__bch2_btree_node_lock_write(b, iter);
	234	}
	235
	236	#endif /* _BCACHEFS_BTREE_LOCKING_H */
	237
	238