1 // SPDX-License-Identifier: GPL-2.0 2 3 #include "bcachefs.h" 4 #include "buckets_waiting_for_journal.h" 5 #include <linux/hash.h> 6 #include <linux/random.h> 7 8 static inline struct bucket_hashed * 9 bucket_hash(struct buckets_waiting_for_journal_table *t, 10 unsigned hash_seed_idx, u64 dev_bucket) 11 { 12 return t->d + hash_64(dev_bucket ^ t->hash_seeds[hash_seed_idx], t->bits); 13 } 14 15 static void bucket_table_init(struct buckets_waiting_for_journal_table *t, size_t bits) 16 { 17 unsigned i; 18 19 t->bits = bits; 20 for (i = 0; i < ARRAY_SIZE(t->hash_seeds); i++) 21 get_random_bytes(&t->hash_seeds[i], sizeof(t->hash_seeds[i])); 22 memset(t->d, 0, sizeof(t->d[0]) << t->bits); 23 } 24 25 u64 bch2_bucket_journal_seq_ready(struct buckets_waiting_for_journal *b, 26 unsigned dev, u64 bucket) 27 { 28 struct buckets_waiting_for_journal_table *t; 29 u64 dev_bucket = (u64) dev << 56 | bucket; 30 u64 ret = 0; 31 32 mutex_lock(&b->lock); 33 t = b->t; 34 35 for (unsigned i = 0; i < ARRAY_SIZE(t->hash_seeds); i++) { 36 struct bucket_hashed *h = bucket_hash(t, i, dev_bucket); 37 38 if (h->dev_bucket == dev_bucket) { 39 ret = h->journal_seq; 40 break; 41 } 42 } 43 44 mutex_unlock(&b->lock); 45 46 return ret; 47 } 48 49 static bool bucket_table_insert(struct buckets_waiting_for_journal_table *t, 50 struct bucket_hashed *new, 51 u64 flushed_seq) 52 { 53 struct bucket_hashed *last_evicted = NULL; 54 unsigned tries, i; 55 56 for (tries = 0; tries < 10; tries++) { 57 struct bucket_hashed *old, *victim = NULL; 58 59 for (i = 0; i < ARRAY_SIZE(t->hash_seeds); i++) { 60 old = bucket_hash(t, i, new->dev_bucket); 61 62 if (old->dev_bucket == new->dev_bucket || 63 old->journal_seq <= flushed_seq) { 64 *old = *new; 65 return true; 66 } 67 68 if (last_evicted != old) 69 victim = old; 70 } 71 72 /* hashed to same slot 3 times: */ 73 if (!victim) 74 break; 75 76 /* Failed to find an empty slot: */ 77 swap(*new, *victim); 78 last_evicted = victim; 79 } 80 81 return false; 82 } 83 84 int bch2_set_bucket_needs_journal_commit(struct buckets_waiting_for_journal *b, 85 u64 flushed_seq, 86 unsigned dev, u64 bucket, 87 u64 journal_seq) 88 { 89 struct buckets_waiting_for_journal_table *t, *n; 90 struct bucket_hashed tmp, new = { 91 .dev_bucket = (u64) dev << 56 | bucket, 92 .journal_seq = journal_seq, 93 }; 94 size_t i, size, new_bits, nr_elements = 1, nr_rehashes = 0, nr_rehashes_this_size = 0; 95 int ret = 0; 96 97 mutex_lock(&b->lock); 98 99 if (likely(bucket_table_insert(b->t, &new, flushed_seq))) 100 goto out; 101 102 t = b->t; 103 size = 1UL << t->bits; 104 for (i = 0; i < size; i++) 105 nr_elements += t->d[i].journal_seq > flushed_seq; 106 107 new_bits = ilog2(roundup_pow_of_two(nr_elements * 3)); 108 realloc: 109 n = kvmalloc(sizeof(*n) + (sizeof(n->d[0]) << new_bits), GFP_KERNEL); 110 if (!n) { 111 ret = -BCH_ERR_ENOMEM_buckets_waiting_for_journal_set; 112 goto out; 113 } 114 115 retry_rehash: 116 if (nr_rehashes_this_size == 3) { 117 new_bits++; 118 nr_rehashes_this_size = 0; 119 kvfree(n); 120 goto realloc; 121 } 122 123 nr_rehashes++; 124 nr_rehashes_this_size++; 125 126 bucket_table_init(n, new_bits); 127 128 tmp = new; 129 BUG_ON(!bucket_table_insert(n, &tmp, flushed_seq)); 130 131 for (i = 0; i < 1UL << t->bits; i++) { 132 if (t->d[i].journal_seq <= flushed_seq) 133 continue; 134 135 tmp = t->d[i]; 136 if (!bucket_table_insert(n, &tmp, flushed_seq)) 137 goto retry_rehash; 138 } 139 140 b->t = n; 141 kvfree(t); 142 143 pr_debug("took %zu rehashes, table at %zu/%lu elements", 144 nr_rehashes, nr_elements, 1UL << b->t->bits); 145 out: 146 mutex_unlock(&b->lock); 147 148 return ret; 149 } 150 151 void bch2_fs_buckets_waiting_for_journal_exit(struct bch_fs *c) 152 { 153 struct buckets_waiting_for_journal *b = &c->buckets_waiting_for_journal; 154 155 kvfree(b->t); 156 } 157 158 #define INITIAL_TABLE_BITS 3 159 160 int bch2_fs_buckets_waiting_for_journal_init(struct bch_fs *c) 161 { 162 struct buckets_waiting_for_journal *b = &c->buckets_waiting_for_journal; 163 164 mutex_init(&b->lock); 165 166 b->t = kvmalloc(sizeof(*b->t) + 167 (sizeof(b->t->d[0]) << INITIAL_TABLE_BITS), GFP_KERNEL); 168 if (!b->t) 169 return -BCH_ERR_ENOMEM_buckets_waiting_for_journal_init; 170 171 bucket_table_init(b->t, INITIAL_TABLE_BITS); 172 return 0; 173 } 174