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, NULL, bio->bi_inline_vecs, 30 meta_bucket_pages(&c->cache->sb), 0); 31 32 return bio; 33 } 34 35 void __bch_submit_bbio(struct bio *bio, struct cache_set *c) 36 { 37 struct bbio *b = container_of(bio, struct bbio, bio); 38 39 bio->bi_iter.bi_sector = PTR_OFFSET(&b->key, 0); 40 bio_set_dev(bio, c->cache->bdev); 41 42 b->submit_time_us = local_clock_us(); 43 closure_bio_submit(c, bio, bio->bi_private); 44 } 45 46 void bch_submit_bbio(struct bio *bio, struct cache_set *c, 47 struct bkey *k, unsigned int ptr) 48 { 49 struct bbio *b = container_of(bio, struct bbio, bio); 50 51 bch_bkey_copy_single_ptr(&b->key, k, ptr); 52 __bch_submit_bbio(bio, c); 53 } 54 55 /* IO errors */ 56 void bch_count_backing_io_errors(struct cached_dev *dc, struct bio *bio) 57 { 58 unsigned int errors; 59 60 WARN_ONCE(!dc, "NULL pointer of struct cached_dev"); 61 62 /* 63 * Read-ahead requests on a degrading and recovering md raid 64 * (e.g. raid6) device might be failured immediately by md 65 * raid code, which is not a real hardware media failure. So 66 * we shouldn't count failed REQ_RAHEAD bio to dc->io_errors. 67 */ 68 if (bio->bi_opf & REQ_RAHEAD) { 69 pr_warn_ratelimited("%pg: Read-ahead I/O failed on backing device, ignore\n", 70 dc->bdev); 71 return; 72 } 73 74 errors = atomic_add_return(1, &dc->io_errors); 75 if (errors < dc->error_limit) 76 pr_err("%pg: IO error on backing device, unrecoverable\n", 77 dc->bdev); 78 else 79 bch_cached_dev_error(dc); 80 } 81 82 void bch_count_io_errors(struct cache *ca, 83 blk_status_t error, 84 int is_read, 85 const char *m) 86 { 87 /* 88 * The halflife of an error is: 89 * log2(1/2)/log2(127/128) * refresh ~= 88 * refresh 90 */ 91 92 if (ca->set->error_decay) { 93 unsigned int count = atomic_inc_return(&ca->io_count); 94 95 while (count > ca->set->error_decay) { 96 unsigned int errors; 97 unsigned int old = count; 98 unsigned int new = count - ca->set->error_decay; 99 100 /* 101 * First we subtract refresh from count; each time we 102 * successfully do so, we rescale the errors once: 103 */ 104 105 count = atomic_cmpxchg(&ca->io_count, old, new); 106 107 if (count == old) { 108 count = new; 109 110 errors = atomic_read(&ca->io_errors); 111 do { 112 old = errors; 113 new = ((uint64_t) errors * 127) / 128; 114 errors = atomic_cmpxchg(&ca->io_errors, 115 old, new); 116 } while (old != errors); 117 } 118 } 119 } 120 121 if (error) { 122 unsigned int errors = atomic_add_return(1 << IO_ERROR_SHIFT, 123 &ca->io_errors); 124 errors >>= IO_ERROR_SHIFT; 125 126 if (errors < ca->set->error_limit) 127 pr_err("%pg: IO error on %s%s\n", 128 ca->bdev, m, 129 is_read ? ", recovering." : "."); 130 else 131 bch_cache_set_error(ca->set, 132 "%pg: too many IO errors %s\n", 133 ca->bdev, m); 134 } 135 } 136 137 void bch_bbio_count_io_errors(struct cache_set *c, struct bio *bio, 138 blk_status_t error, const char *m) 139 { 140 struct bbio *b = container_of(bio, struct bbio, bio); 141 struct cache *ca = c->cache; 142 int is_read = (bio_data_dir(bio) == READ ? 1 : 0); 143 144 unsigned int threshold = op_is_write(bio_op(bio)) 145 ? c->congested_write_threshold_us 146 : c->congested_read_threshold_us; 147 148 if (threshold) { 149 unsigned int t = local_clock_us(); 150 int us = t - b->submit_time_us; 151 int congested = atomic_read(&c->congested); 152 153 if (us > (int) threshold) { 154 int ms = us / 1024; 155 156 c->congested_last_us = t; 157 158 ms = min(ms, CONGESTED_MAX + congested); 159 atomic_sub(ms, &c->congested); 160 } else if (congested < 0) 161 atomic_inc(&c->congested); 162 } 163 164 bch_count_io_errors(ca, error, is_read, m); 165 } 166 167 void bch_bbio_endio(struct cache_set *c, struct bio *bio, 168 blk_status_t error, const char *m) 169 { 170 struct closure *cl = bio->bi_private; 171 172 bch_bbio_count_io_errors(c, bio, error, m); 173 bio_put(bio); 174 closure_put(cl); 175 } 176