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
bch_bbio_free(struct bio * bio,struct cache_set * c)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
bch_bbio_alloc(struct cache_set * c)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, bucket_pages(c));
30
31 return bio;
32 }
33
__bch_submit_bbio(struct bio * bio,struct cache_set * c)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, 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
bch_submit_bbio(struct bio * bio,struct cache_set * c,struct bkey * k,unsigned int ptr)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 */
bch_count_backing_io_errors(struct cached_dev * dc,struct bio * bio)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",
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",
76 dc->backing_dev_name);
77 else
78 bch_cached_dev_error(dc);
79 }
80
bch_count_io_errors(struct cache * ca,blk_status_t error,int is_read,const char * m)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",
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",
132 ca->cache_dev_name, m);
133 }
134 }
135
bch_bbio_count_io_errors(struct cache_set * c,struct bio * bio,blk_status_t error,const char * m)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 = PTR_CACHE(c, &b->key, 0);
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
bch_bbio_endio(struct cache_set * c,struct bio * bio,blk_status_t error,const char * m)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
