2 * Some low level IO code, and hacks for various block layer limitations
4 * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
5 * Copyright 2012 Google, Inc.
12 #include <linux/blkdev.h>
14 /* Bios with headers */
16 void bch_bbio_free(struct bio *bio, struct cache_set *c)
18 struct bbio *b = container_of(bio, struct bbio, bio);
19 mempool_free(b, c->bio_meta);
22 struct bio *bch_bbio_alloc(struct cache_set *c)
24 struct bbio *b = mempool_alloc(c->bio_meta, GFP_NOIO);
25 struct bio *bio = &b->bio;
28 bio->bi_flags |= BIO_POOL_NONE << BIO_POOL_OFFSET;
29 bio->bi_max_vecs = bucket_pages(c);
30 bio->bi_io_vec = bio->bi_inline_vecs;
35 void __bch_submit_bbio(struct bio *bio, struct cache_set *c)
37 struct bbio *b = container_of(bio, struct bbio, bio);
39 bio->bi_iter.bi_sector = PTR_OFFSET(&b->key, 0);
40 bio->bi_bdev = PTR_CACHE(c, &b->key, 0)->bdev;
42 b->submit_time_us = local_clock_us();
43 closure_bio_submit(bio, bio->bi_private);
46 void bch_submit_bbio(struct bio *bio, struct cache_set *c,
47 struct bkey *k, unsigned ptr)
49 struct bbio *b = container_of(bio, struct bbio, bio);
50 bch_bkey_copy_single_ptr(&b->key, k, ptr);
51 __bch_submit_bbio(bio, c);
56 void bch_count_io_errors(struct cache *ca, int error, const char *m)
59 * The halflife of an error is:
60 * log2(1/2)/log2(127/128) * refresh ~= 88 * refresh
63 if (ca->set->error_decay) {
64 unsigned count = atomic_inc_return(&ca->io_count);
66 while (count > ca->set->error_decay) {
69 unsigned new = count - ca->set->error_decay;
72 * First we subtract refresh from count; each time we
73 * succesfully do so, we rescale the errors once:
76 count = atomic_cmpxchg(&ca->io_count, old, new);
81 errors = atomic_read(&ca->io_errors);
84 new = ((uint64_t) errors * 127) / 128;
85 errors = atomic_cmpxchg(&ca->io_errors,
87 } while (old != errors);
93 char buf[BDEVNAME_SIZE];
94 unsigned errors = atomic_add_return(1 << IO_ERROR_SHIFT,
96 errors >>= IO_ERROR_SHIFT;
98 if (errors < ca->set->error_limit)
99 pr_err("%s: IO error on %s, recovering",
100 bdevname(ca->bdev, buf), m);
102 bch_cache_set_error(ca->set,
103 "%s: too many IO errors %s",
104 bdevname(ca->bdev, buf), m);
108 void bch_bbio_count_io_errors(struct cache_set *c, struct bio *bio,
109 int error, const char *m)
111 struct bbio *b = container_of(bio, struct bbio, bio);
112 struct cache *ca = PTR_CACHE(c, &b->key, 0);
114 unsigned threshold = bio->bi_rw & REQ_WRITE
115 ? c->congested_write_threshold_us
116 : c->congested_read_threshold_us;
119 unsigned t = local_clock_us();
121 int us = t - b->submit_time_us;
122 int congested = atomic_read(&c->congested);
124 if (us > (int) threshold) {
126 c->congested_last_us = t;
128 ms = min(ms, CONGESTED_MAX + congested);
129 atomic_sub(ms, &c->congested);
130 } else if (congested < 0)
131 atomic_inc(&c->congested);
134 bch_count_io_errors(ca, error, m);
137 void bch_bbio_endio(struct cache_set *c, struct bio *bio,
138 int error, const char *m)
140 struct closure *cl = bio->bi_private;
142 bch_bbio_count_io_errors(c, bio, error, m);