1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Some low level IO code, and hacks for various block layer limitations 4 * 5 * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com> 6 * Copyright 2012 Google, Inc. 7 */ 8 9 #include "bcache.h" 10 #include "bset.h" 11 #include "debug.h" 12 13 #include <linux/blkdev.h> 14 15 /* Bios with headers */ 16 17 void bch_bbio_free(struct bio *bio, struct cache_set *c) 18 { 19 struct bbio *b = container_of(bio, struct bbio, bio); 20 mempool_free(b, &c->bio_meta); 21 } 22 23 struct bio *bch_bbio_alloc(struct cache_set *c) 24 { 25 struct bbio *b = mempool_alloc(&c->bio_meta, GFP_NOIO); 26 struct bio *bio = &b->bio; 27 28 bio_init(bio, bio->bi_inline_vecs, bucket_pages(c)); 29 30 return bio; 31 } 32 33 void __bch_submit_bbio(struct bio *bio, struct cache_set *c) 34 { 35 struct bbio *b = container_of(bio, struct bbio, bio); 36 37 bio->bi_iter.bi_sector = PTR_OFFSET(&b->key, 0); 38 bio_set_dev(bio, PTR_CACHE(c, &b->key, 0)->bdev); 39 40 b->submit_time_us = local_clock_us(); 41 closure_bio_submit(c, bio, bio->bi_private); 42 } 43 44 void bch_submit_bbio(struct bio *bio, struct cache_set *c, 45 struct bkey *k, unsigned ptr) 46 { 47 struct bbio *b = container_of(bio, struct bbio, bio); 48 bch_bkey_copy_single_ptr(&b->key, k, ptr); 49 __bch_submit_bbio(bio, c); 50 } 51 52 /* IO errors */ 53 void bch_count_backing_io_errors(struct cached_dev *dc, struct bio *bio) 54 { 55 unsigned errors; 56 57 WARN_ONCE(!dc, "NULL pointer of struct cached_dev"); 58 59 errors = atomic_add_return(1, &dc->io_errors); 60 if (errors < dc->error_limit) 61 pr_err("%s: IO error on backing device, unrecoverable", 62 dc->backing_dev_name); 63 else 64 bch_cached_dev_error(dc); 65 } 66 67 void bch_count_io_errors(struct cache *ca, 68 blk_status_t error, 69 int is_read, 70 const char *m) 71 { 72 /* 73 * The halflife of an error is: 74 * log2(1/2)/log2(127/128) * refresh ~= 88 * refresh 75 */ 76 77 if (ca->set->error_decay) { 78 unsigned count = atomic_inc_return(&ca->io_count); 79 80 while (count > ca->set->error_decay) { 81 unsigned errors; 82 unsigned old = count; 83 unsigned new = count - ca->set->error_decay; 84 85 /* 86 * First we subtract refresh from count; each time we 87 * succesfully do so, we rescale the errors once: 88 */ 89 90 count = atomic_cmpxchg(&ca->io_count, old, new); 91 92 if (count == old) { 93 count = new; 94 95 errors = atomic_read(&ca->io_errors); 96 do { 97 old = errors; 98 new = ((uint64_t) errors * 127) / 128; 99 errors = atomic_cmpxchg(&ca->io_errors, 100 old, new); 101 } while (old != errors); 102 } 103 } 104 } 105 106 if (error) { 107 unsigned errors = atomic_add_return(1 << IO_ERROR_SHIFT, 108 &ca->io_errors); 109 errors >>= IO_ERROR_SHIFT; 110 111 if (errors < ca->set->error_limit) 112 pr_err("%s: IO error on %s%s", 113 ca->cache_dev_name, m, 114 is_read ? ", recovering." : "."); 115 else 116 bch_cache_set_error(ca->set, 117 "%s: too many IO errors %s", 118 ca->cache_dev_name, m); 119 } 120 } 121 122 void bch_bbio_count_io_errors(struct cache_set *c, struct bio *bio, 123 blk_status_t error, const char *m) 124 { 125 struct bbio *b = container_of(bio, struct bbio, bio); 126 struct cache *ca = PTR_CACHE(c, &b->key, 0); 127 int is_read = (bio_data_dir(bio) == READ ? 1 : 0); 128 129 unsigned threshold = op_is_write(bio_op(bio)) 130 ? c->congested_write_threshold_us 131 : c->congested_read_threshold_us; 132 133 if (threshold) { 134 unsigned t = local_clock_us(); 135 136 int us = t - b->submit_time_us; 137 int congested = atomic_read(&c->congested); 138 139 if (us > (int) threshold) { 140 int ms = us / 1024; 141 c->congested_last_us = t; 142 143 ms = min(ms, CONGESTED_MAX + congested); 144 atomic_sub(ms, &c->congested); 145 } else if (congested < 0) 146 atomic_inc(&c->congested); 147 } 148 149 bch_count_io_errors(ca, error, is_read, m); 150 } 151 152 void bch_bbio_endio(struct cache_set *c, struct bio *bio, 153 blk_status_t error, const char *m) 154 { 155 struct closure *cl = bio->bi_private; 156 157 bch_bbio_count_io_errors(c, bio, error, m); 158 bio_put(bio); 159 closure_put(cl); 160 } 161