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