425 lines
12 KiB
C
425 lines
12 KiB
C
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/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _BCACHEFS_BTREE_LOCKING_H
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#define _BCACHEFS_BTREE_LOCKING_H
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/*
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* Only for internal btree use:
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*
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* The btree iterator tracks what locks it wants to take, and what locks it
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* currently has - here we have wrappers for locking/unlocking btree nodes and
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* updating the iterator state
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*/
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#include "btree_iter.h"
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#include "six.h"
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void bch2_btree_lock_init(struct btree_bkey_cached_common *, enum six_lock_init_flags);
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#ifdef CONFIG_LOCKDEP
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void bch2_assert_btree_nodes_not_locked(void);
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#else
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static inline void bch2_assert_btree_nodes_not_locked(void) {}
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#endif
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void bch2_trans_unlock_noassert(struct btree_trans *);
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static inline bool is_btree_node(struct btree_path *path, unsigned l)
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{
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return l < BTREE_MAX_DEPTH && !IS_ERR_OR_NULL(path->l[l].b);
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}
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static inline struct btree_transaction_stats *btree_trans_stats(struct btree_trans *trans)
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{
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return trans->fn_idx < ARRAY_SIZE(trans->c->btree_transaction_stats)
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? &trans->c->btree_transaction_stats[trans->fn_idx]
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: NULL;
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}
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/* matches six lock types */
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enum btree_node_locked_type {
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BTREE_NODE_UNLOCKED = -1,
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BTREE_NODE_READ_LOCKED = SIX_LOCK_read,
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BTREE_NODE_INTENT_LOCKED = SIX_LOCK_intent,
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BTREE_NODE_WRITE_LOCKED = SIX_LOCK_write,
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};
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static inline int btree_node_locked_type(struct btree_path *path,
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unsigned level)
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{
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return BTREE_NODE_UNLOCKED + ((path->nodes_locked >> (level << 1)) & 3);
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}
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static inline bool btree_node_write_locked(struct btree_path *path, unsigned l)
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{
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return btree_node_locked_type(path, l) == BTREE_NODE_WRITE_LOCKED;
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}
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static inline bool btree_node_intent_locked(struct btree_path *path, unsigned l)
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{
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return btree_node_locked_type(path, l) == BTREE_NODE_INTENT_LOCKED;
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}
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static inline bool btree_node_read_locked(struct btree_path *path, unsigned l)
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{
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return btree_node_locked_type(path, l) == BTREE_NODE_READ_LOCKED;
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}
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static inline bool btree_node_locked(struct btree_path *path, unsigned level)
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{
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return btree_node_locked_type(path, level) != BTREE_NODE_UNLOCKED;
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}
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static inline void mark_btree_node_locked_noreset(struct btree_path *path,
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unsigned level,
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enum btree_node_locked_type type)
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{
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/* relying on this to avoid a branch */
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BUILD_BUG_ON(SIX_LOCK_read != 0);
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BUILD_BUG_ON(SIX_LOCK_intent != 1);
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path->nodes_locked &= ~(3U << (level << 1));
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path->nodes_locked |= (type + 1) << (level << 1);
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}
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static inline void mark_btree_node_unlocked(struct btree_path *path,
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unsigned level)
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{
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EBUG_ON(btree_node_write_locked(path, level));
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mark_btree_node_locked_noreset(path, level, BTREE_NODE_UNLOCKED);
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}
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static inline void mark_btree_node_locked(struct btree_trans *trans,
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struct btree_path *path,
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unsigned level,
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enum btree_node_locked_type type)
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{
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mark_btree_node_locked_noreset(path, level, (enum btree_node_locked_type) type);
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#ifdef CONFIG_BCACHEFS_LOCK_TIME_STATS
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path->l[level].lock_taken_time = local_clock();
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#endif
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}
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static inline enum six_lock_type __btree_lock_want(struct btree_path *path, int level)
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{
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return level < path->locks_want
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? SIX_LOCK_intent
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: SIX_LOCK_read;
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}
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static inline enum btree_node_locked_type
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btree_lock_want(struct btree_path *path, int level)
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{
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if (level < path->level)
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return BTREE_NODE_UNLOCKED;
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if (level < path->locks_want)
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return BTREE_NODE_INTENT_LOCKED;
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if (level == path->level)
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return BTREE_NODE_READ_LOCKED;
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return BTREE_NODE_UNLOCKED;
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}
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static void btree_trans_lock_hold_time_update(struct btree_trans *trans,
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struct btree_path *path, unsigned level)
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{
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#ifdef CONFIG_BCACHEFS_LOCK_TIME_STATS
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__bch2_time_stats_update(&btree_trans_stats(trans)->lock_hold_times,
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path->l[level].lock_taken_time,
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local_clock());
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#endif
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}
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/* unlock: */
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static inline void btree_node_unlock(struct btree_trans *trans,
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struct btree_path *path, unsigned level)
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{
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int lock_type = btree_node_locked_type(path, level);
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EBUG_ON(level >= BTREE_MAX_DEPTH);
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if (lock_type != BTREE_NODE_UNLOCKED) {
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six_unlock_type(&path->l[level].b->c.lock, lock_type);
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btree_trans_lock_hold_time_update(trans, path, level);
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}
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mark_btree_node_unlocked(path, level);
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}
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static inline int btree_path_lowest_level_locked(struct btree_path *path)
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{
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return __ffs(path->nodes_locked) >> 1;
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}
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static inline int btree_path_highest_level_locked(struct btree_path *path)
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{
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return __fls(path->nodes_locked) >> 1;
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}
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static inline void __bch2_btree_path_unlock(struct btree_trans *trans,
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struct btree_path *path)
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{
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btree_path_set_dirty(path, BTREE_ITER_NEED_RELOCK);
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while (path->nodes_locked)
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btree_node_unlock(trans, path, btree_path_lowest_level_locked(path));
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}
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/*
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* Updates the saved lock sequence number, so that bch2_btree_node_relock() will
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* succeed:
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*/
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static inline void
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bch2_btree_node_unlock_write_inlined(struct btree_trans *trans, struct btree_path *path,
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struct btree *b)
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{
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struct btree_path *linked;
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unsigned i;
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EBUG_ON(path->l[b->c.level].b != b);
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EBUG_ON(path->l[b->c.level].lock_seq != six_lock_seq(&b->c.lock));
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EBUG_ON(btree_node_locked_type(path, b->c.level) != SIX_LOCK_write);
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mark_btree_node_locked_noreset(path, b->c.level, BTREE_NODE_INTENT_LOCKED);
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trans_for_each_path_with_node(trans, b, linked, i)
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linked->l[b->c.level].lock_seq++;
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six_unlock_write(&b->c.lock);
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}
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void bch2_btree_node_unlock_write(struct btree_trans *,
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struct btree_path *, struct btree *);
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int bch2_six_check_for_deadlock(struct six_lock *lock, void *p);
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/* lock: */
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static inline int __btree_node_lock_nopath(struct btree_trans *trans,
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struct btree_bkey_cached_common *b,
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enum six_lock_type type,
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bool lock_may_not_fail,
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unsigned long ip)
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{
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int ret;
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trans->lock_may_not_fail = lock_may_not_fail;
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trans->lock_must_abort = false;
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trans->locking = b;
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ret = six_lock_ip_waiter(&b->lock, type, &trans->locking_wait,
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bch2_six_check_for_deadlock, trans, ip);
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WRITE_ONCE(trans->locking, NULL);
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WRITE_ONCE(trans->locking_wait.start_time, 0);
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return ret;
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}
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static inline int __must_check
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btree_node_lock_nopath(struct btree_trans *trans,
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struct btree_bkey_cached_common *b,
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enum six_lock_type type,
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unsigned long ip)
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{
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return __btree_node_lock_nopath(trans, b, type, false, ip);
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}
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static inline void btree_node_lock_nopath_nofail(struct btree_trans *trans,
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struct btree_bkey_cached_common *b,
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enum six_lock_type type)
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{
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int ret = __btree_node_lock_nopath(trans, b, type, true, _THIS_IP_);
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BUG_ON(ret);
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}
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/*
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* Lock a btree node if we already have it locked on one of our linked
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* iterators:
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*/
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static inline bool btree_node_lock_increment(struct btree_trans *trans,
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struct btree_bkey_cached_common *b,
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unsigned level,
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enum btree_node_locked_type want)
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{
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struct btree_path *path;
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unsigned i;
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trans_for_each_path(trans, path, i)
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if (&path->l[level].b->c == b &&
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btree_node_locked_type(path, level) >= want) {
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six_lock_increment(&b->lock, (enum six_lock_type) want);
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return true;
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}
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return false;
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}
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static inline int btree_node_lock(struct btree_trans *trans,
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struct btree_path *path,
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struct btree_bkey_cached_common *b,
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unsigned level,
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enum six_lock_type type,
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unsigned long ip)
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{
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int ret = 0;
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EBUG_ON(level >= BTREE_MAX_DEPTH);
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if (likely(six_trylock_type(&b->lock, type)) ||
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btree_node_lock_increment(trans, b, level, (enum btree_node_locked_type) type) ||
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!(ret = btree_node_lock_nopath(trans, b, type, btree_path_ip_allocated(path)))) {
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#ifdef CONFIG_BCACHEFS_LOCK_TIME_STATS
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path->l[b->level].lock_taken_time = local_clock();
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#endif
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}
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return ret;
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}
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int __bch2_btree_node_lock_write(struct btree_trans *, struct btree_path *,
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struct btree_bkey_cached_common *b, bool);
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static inline int __btree_node_lock_write(struct btree_trans *trans,
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struct btree_path *path,
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struct btree_bkey_cached_common *b,
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bool lock_may_not_fail)
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{
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EBUG_ON(&path->l[b->level].b->c != b);
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EBUG_ON(path->l[b->level].lock_seq != six_lock_seq(&b->lock));
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EBUG_ON(!btree_node_intent_locked(path, b->level));
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/*
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* six locks are unfair, and read locks block while a thread wants a
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* write lock: thus, we need to tell the cycle detector we have a write
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* lock _before_ taking the lock:
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*/
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mark_btree_node_locked_noreset(path, b->level, BTREE_NODE_WRITE_LOCKED);
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return likely(six_trylock_write(&b->lock))
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? 0
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: __bch2_btree_node_lock_write(trans, path, b, lock_may_not_fail);
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}
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static inline int __must_check
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bch2_btree_node_lock_write(struct btree_trans *trans,
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struct btree_path *path,
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struct btree_bkey_cached_common *b)
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{
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return __btree_node_lock_write(trans, path, b, false);
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}
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void bch2_btree_node_lock_write_nofail(struct btree_trans *,
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struct btree_path *,
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struct btree_bkey_cached_common *);
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/* relock: */
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bool bch2_btree_path_relock_norestart(struct btree_trans *, struct btree_path *);
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int __bch2_btree_path_relock(struct btree_trans *,
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struct btree_path *, unsigned long);
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static inline int bch2_btree_path_relock(struct btree_trans *trans,
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struct btree_path *path, unsigned long trace_ip)
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{
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return btree_node_locked(path, path->level)
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? 0
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: __bch2_btree_path_relock(trans, path, trace_ip);
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}
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bool __bch2_btree_node_relock(struct btree_trans *, struct btree_path *, unsigned, bool trace);
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static inline bool bch2_btree_node_relock(struct btree_trans *trans,
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struct btree_path *path, unsigned level)
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{
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EBUG_ON(btree_node_locked(path, level) &&
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!btree_node_write_locked(path, level) &&
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btree_node_locked_type(path, level) != __btree_lock_want(path, level));
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return likely(btree_node_locked(path, level)) ||
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(!IS_ERR_OR_NULL(path->l[level].b) &&
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__bch2_btree_node_relock(trans, path, level, true));
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}
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static inline bool bch2_btree_node_relock_notrace(struct btree_trans *trans,
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struct btree_path *path, unsigned level)
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{
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EBUG_ON(btree_node_locked(path, level) &&
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!btree_node_write_locked(path, level) &&
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btree_node_locked_type(path, level) != __btree_lock_want(path, level));
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return likely(btree_node_locked(path, level)) ||
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(!IS_ERR_OR_NULL(path->l[level].b) &&
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__bch2_btree_node_relock(trans, path, level, false));
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}
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/* upgrade */
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|
bool bch2_btree_path_upgrade_noupgrade_sibs(struct btree_trans *,
|
||
|
|
struct btree_path *, unsigned,
|
||
|
|
struct get_locks_fail *);
|
||
|
|
|
||
|
|
bool __bch2_btree_path_upgrade(struct btree_trans *,
|
||
|
|
struct btree_path *, unsigned,
|
||
|
|
struct get_locks_fail *);
|
||
|
|
|
||
|
|
static inline int bch2_btree_path_upgrade(struct btree_trans *trans,
|
||
|
|
struct btree_path *path,
|
||
|
|
unsigned new_locks_want)
|
||
|
|
{
|
||
|
|
struct get_locks_fail f;
|
||
|
|
unsigned old_locks_want = path->locks_want;
|
||
|
|
|
||
|
|
new_locks_want = min(new_locks_want, BTREE_MAX_DEPTH);
|
||
|
|
|
||
|
|
if (path->locks_want < new_locks_want
|
||
|
|
? __bch2_btree_path_upgrade(trans, path, new_locks_want, &f)
|
||
|
|
: path->uptodate == BTREE_ITER_UPTODATE)
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
trace_and_count(trans->c, trans_restart_upgrade, trans, _THIS_IP_, path,
|
||
|
|
old_locks_want, new_locks_want, &f);
|
||
|
|
return btree_trans_restart(trans, BCH_ERR_transaction_restart_upgrade);
|
||
|
|
}
|
||
|
|
|
||
|
|
/* misc: */
|
||
|
|
|
||
|
|
static inline void btree_path_set_should_be_locked(struct btree_path *path)
|
||
|
|
{
|
||
|
|
EBUG_ON(!btree_node_locked(path, path->level));
|
||
|
|
EBUG_ON(path->uptodate);
|
||
|
|
|
||
|
|
path->should_be_locked = true;
|
||
|
|
}
|
||
|
|
|
||
|
|
static inline void __btree_path_set_level_up(struct btree_trans *trans,
|
||
|
|
struct btree_path *path,
|
||
|
|
unsigned l)
|
||
|
|
{
|
||
|
|
btree_node_unlock(trans, path, l);
|
||
|
|
path->l[l].b = ERR_PTR(-BCH_ERR_no_btree_node_up);
|
||
|
|
}
|
||
|
|
|
||
|
|
static inline void btree_path_set_level_up(struct btree_trans *trans,
|
||
|
|
struct btree_path *path)
|
||
|
|
{
|
||
|
|
__btree_path_set_level_up(trans, path, path->level++);
|
||
|
|
btree_path_set_dirty(path, BTREE_ITER_NEED_TRAVERSE);
|
||
|
|
}
|
||
|
|
|
||
|
|
/* debug */
|
||
|
|
|
||
|
|
struct six_lock_count bch2_btree_node_lock_counts(struct btree_trans *,
|
||
|
|
struct btree_path *,
|
||
|
|
struct btree_bkey_cached_common *b,
|
||
|
|
unsigned);
|
||
|
|
|
||
|
|
int bch2_check_for_deadlock(struct btree_trans *, struct printbuf *);
|
||
|
|
|
||
|
|
#ifdef CONFIG_BCACHEFS_DEBUG
|
||
|
|
void bch2_btree_path_verify_locks(struct btree_path *);
|
||
|
|
void bch2_trans_verify_locks(struct btree_trans *);
|
||
|
|
#else
|
||
|
|
static inline void bch2_btree_path_verify_locks(struct btree_path *path) {}
|
||
|
|
static inline void bch2_trans_verify_locks(struct btree_trans *trans) {}
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#endif /* _BCACHEFS_BTREE_LOCKING_H */
|