tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
17void 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
24struct 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, bucket_pages(c));
30
31 return bio;
32}
33
34void __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, PTR_CACHE(c, &b->key, 0)->bdev);
40
41 b->submit_time_us = local_clock_us();
42 closure_bio_submit(c, bio, bio->bi_private);
43}
44
45void 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 */
55void 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 errors = atomic_add_return(1, &dc->io_errors);
62 if (errors < dc->error_limit)
63 pr_err("%s: IO error on backing device, unrecoverable",
64 dc->backing_dev_name);
65 else
66 bch_cached_dev_error(dc);
67}
68
69void bch_count_io_errors(struct cache *ca,
70 blk_status_t error,
71 int is_read,
72 const char *m)
73{
74 /*
75 * The halflife of an error is:
76 * log2(1/2)/log2(127/128) * refresh ~= 88 * refresh
77 */
78
79 if (ca->set->error_decay) {
80 unsigned int count = atomic_inc_return(&ca->io_count);
81
82 while (count > ca->set->error_decay) {
83 unsigned int errors;
84 unsigned int old = count;
85 unsigned int new = count - ca->set->error_decay;
86
87 /*
88 * First we subtract refresh from count; each time we
89 * successfully do so, we rescale the errors once:
90 */
91
92 count = atomic_cmpxchg(&ca->io_count, old, new);
93
94 if (count == old) {
95 count = new;
96
97 errors = atomic_read(&ca->io_errors);
98 do {
99 old = errors;
100 new = ((uint64_t) errors * 127) / 128;
101 errors = atomic_cmpxchg(&ca->io_errors,
102 old, new);
103 } while (old != errors);
104 }
105 }
106 }
107
108 if (error) {
109 unsigned int errors = atomic_add_return(1 << IO_ERROR_SHIFT,
110 &ca->io_errors);
111 errors >>= IO_ERROR_SHIFT;
112
113 if (errors < ca->set->error_limit)
114 pr_err("%s: IO error on %s%s",
115 ca->cache_dev_name, m,
116 is_read ? ", recovering." : ".");
117 else
118 bch_cache_set_error(ca->set,
119 "%s: too many IO errors %s",
120 ca->cache_dev_name, m);
121 }
122}
123
124void bch_bbio_count_io_errors(struct cache_set *c, struct bio *bio,
125 blk_status_t error, const char *m)
126{
127 struct bbio *b = container_of(bio, struct bbio, bio);
128 struct cache *ca = PTR_CACHE(c, &b->key, 0);
129 int is_read = (bio_data_dir(bio) == READ ? 1 : 0);
130
131 unsigned int threshold = op_is_write(bio_op(bio))
132 ? c->congested_write_threshold_us
133 : c->congested_read_threshold_us;
134
135 if (threshold) {
136 unsigned int t = local_clock_us();
137 int us = t - b->submit_time_us;
138 int congested = atomic_read(&c->congested);
139
140 if (us > (int) threshold) {
141 int ms = us / 1024;
142
143 c->congested_last_us = t;
144
145 ms = min(ms, CONGESTED_MAX + congested);
146 atomic_sub(ms, &c->congested);
147 } else if (congested < 0)
148 atomic_inc(&c->congested);
149 }
150
151 bch_count_io_errors(ca, error, is_read, m);
152}
153
154void bch_bbio_endio(struct cache_set *c, struct bio *bio,
155 blk_status_t error, const char *m)
156{
157 struct closure *cl = bio->bi_private;
158
159 bch_bbio_count_io_errors(c, bio, error, m);
160 bio_put(bio);
161 closure_put(cl);
162}