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 21 mempool_free(b, &c->bio_meta); 22 } 23 24 struct bio *bch_bbio_alloc(struct cache_set *c) 25 { 26 struct bbio *b = mempool_alloc(&c->bio_meta, GFP_NOIO); 27 struct bio *bio = &b->bio; 28 29 bio_init(bio, bio->bi_inline_vecs, meta_bucket_pages(&c->cache->sb)); 30 31 return bio; 32 } 33 34 void __bch_submit_bbio(struct bio *bio, struct cache_set *c) 35 { 36 struct bbio *b = container_of(bio, struct bbio, bio); 37 38 bio->bi_iter.bi_sector = PTR_OFFSET(&b->key, 0); 39 bio_set_dev(bio, c->cache->bdev); 40 41 b->submit_time_us = local_clock_us(); 42 closure_bio_submit(c, bio, bio->bi_private); 43 } 44 45 void bch_submit_bbio(struct bio *bio, struct cache_set *c, 46 struct bkey *k, unsigned int ptr) 47 { 48 struct bbio *b = container_of(bio, struct bbio, bio); 49 50 bch_bkey_copy_single_ptr(&b->key, k, ptr); 51 __bch_submit_bbio(bio, c); 52 } 53 54 /* IO errors */ 55 void bch_count_backing_io_errors(struct cached_dev *dc, struct bio *bio) 56 { 57 unsigned int errors; 58 59 WARN_ONCE(!dc, "NULL pointer of struct cached_dev"); 60 61 /* 62 * Read-ahead requests on a degrading and recovering md raid 63 * (e.g. raid6) device might be failured immediately by md 64 * raid code, which is not a real hardware media failure. So 65 * we shouldn't count failed REQ_RAHEAD bio to dc->io_errors. 66 */ 67 if (bio->bi_opf & REQ_RAHEAD) { 68 pr_warn_ratelimited("%s: Read-ahead I/O failed on backing device, ignore\n", 69 dc->backing_dev_name); 70 return; 71 } 72 73 errors = atomic_add_return(1, &dc->io_errors); 74 if (errors < dc->error_limit) 75 pr_err("%s: IO error on backing device, unrecoverable\n", 76 dc->backing_dev_name); 77 else 78 bch_cached_dev_error(dc); 79 } 80 81 void bch_count_io_errors(struct cache *ca, 82 blk_status_t error, 83 int is_read, 84 const char *m) 85 { 86 /* 87 * The halflife of an error is: 88 * log2(1/2)/log2(127/128) * refresh ~= 88 * refresh 89 */ 90 91 if (ca->set->error_decay) { 92 unsigned int count = atomic_inc_return(&ca->io_count); 93 94 while (count > ca->set->error_decay) { 95 unsigned int errors; 96 unsigned int old = count; 97 unsigned int new = count - ca->set->error_decay; 98 99 /* 100 * First we subtract refresh from count; each time we 101 * successfully do so, we rescale the errors once: 102 */ 103 104 count = atomic_cmpxchg(&ca->io_count, old, new); 105 106 if (count == old) { 107 count = new; 108 109 errors = atomic_read(&ca->io_errors); 110 do { 111 old = errors; 112 new = ((uint64_t) errors * 127) / 128; 113 errors = atomic_cmpxchg(&ca->io_errors, 114 old, new); 115 } while (old != errors); 116 } 117 } 118 } 119 120 if (error) { 121 unsigned int errors = atomic_add_return(1 << IO_ERROR_SHIFT, 122 &ca->io_errors); 123 errors >>= IO_ERROR_SHIFT; 124 125 if (errors < ca->set->error_limit) 126 pr_err("%s: IO error on %s%s\n", 127 ca->cache_dev_name, m, 128 is_read ? ", recovering." : "."); 129 else 130 bch_cache_set_error(ca->set, 131 "%s: too many IO errors %s\n", 132 ca->cache_dev_name, m); 133 } 134 } 135 136 void bch_bbio_count_io_errors(struct cache_set *c, struct bio *bio, 137 blk_status_t error, const char *m) 138 { 139 struct bbio *b = container_of(bio, struct bbio, bio); 140 struct cache *ca = c->cache; 141 int is_read = (bio_data_dir(bio) == READ ? 1 : 0); 142 143 unsigned int threshold = op_is_write(bio_op(bio)) 144 ? c->congested_write_threshold_us 145 : c->congested_read_threshold_us; 146 147 if (threshold) { 148 unsigned int t = local_clock_us(); 149 int us = t - b->submit_time_us; 150 int congested = atomic_read(&c->congested); 151 152 if (us > (int) threshold) { 153 int ms = us / 1024; 154 155 c->congested_last_us = t; 156 157 ms = min(ms, CONGESTED_MAX + congested); 158 atomic_sub(ms, &c->congested); 159 } else if (congested < 0) 160 atomic_inc(&c->congested); 161 } 162 163 bch_count_io_errors(ca, error, is_read, m); 164 } 165 166 void bch_bbio_endio(struct cache_set *c, struct bio *bio, 167 blk_status_t error, const char *m) 168 { 169 struct closure *cl = bio->bi_private; 170 171 bch_bbio_count_io_errors(c, bio, error, m); 172 bio_put(bio); 173 closure_put(cl); 174 } 175