145 lines
3.3 KiB
C
145 lines
3.3 KiB
C
/*
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* Some low level IO code, and hacks for various block layer limitations
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*
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* Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
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* Copyright 2012 Google, Inc.
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*/
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#include "bcache.h"
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#include "bset.h"
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#include "debug.h"
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#include <linux/blkdev.h>
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/* Bios with headers */
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void bch_bbio_free(struct bio *bio, struct cache_set *c)
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{
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struct bbio *b = container_of(bio, struct bbio, bio);
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mempool_free(b, c->bio_meta);
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}
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struct bio *bch_bbio_alloc(struct cache_set *c)
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{
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struct bbio *b = mempool_alloc(c->bio_meta, GFP_NOIO);
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struct bio *bio = &b->bio;
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bio_init(bio);
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bio->bi_max_vecs = bucket_pages(c);
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bio->bi_io_vec = bio->bi_inline_vecs;
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return bio;
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}
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void __bch_submit_bbio(struct bio *bio, struct cache_set *c)
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{
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struct bbio *b = container_of(bio, struct bbio, bio);
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bio->bi_iter.bi_sector = PTR_OFFSET(&b->key, 0);
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bio->bi_bdev = PTR_CACHE(c, &b->key, 0)->bdev;
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b->submit_time_us = local_clock_us();
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closure_bio_submit(bio, bio->bi_private);
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}
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void bch_submit_bbio(struct bio *bio, struct cache_set *c,
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struct bkey *k, unsigned ptr)
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{
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struct bbio *b = container_of(bio, struct bbio, bio);
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bch_bkey_copy_single_ptr(&b->key, k, ptr);
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__bch_submit_bbio(bio, c);
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}
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/* IO errors */
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void bch_count_io_errors(struct cache *ca, int error, const char *m)
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{
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/*
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* The halflife of an error is:
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* log2(1/2)/log2(127/128) * refresh ~= 88 * refresh
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*/
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if (ca->set->error_decay) {
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unsigned count = atomic_inc_return(&ca->io_count);
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while (count > ca->set->error_decay) {
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unsigned errors;
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unsigned old = count;
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unsigned new = count - ca->set->error_decay;
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/*
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* First we subtract refresh from count; each time we
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* succesfully do so, we rescale the errors once:
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*/
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count = atomic_cmpxchg(&ca->io_count, old, new);
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if (count == old) {
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count = new;
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errors = atomic_read(&ca->io_errors);
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do {
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old = errors;
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new = ((uint64_t) errors * 127) / 128;
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errors = atomic_cmpxchg(&ca->io_errors,
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old, new);
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} while (old != errors);
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}
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}
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}
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if (error) {
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char buf[BDEVNAME_SIZE];
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unsigned errors = atomic_add_return(1 << IO_ERROR_SHIFT,
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&ca->io_errors);
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errors >>= IO_ERROR_SHIFT;
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if (errors < ca->set->error_limit)
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pr_err("%s: IO error on %s, recovering",
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bdevname(ca->bdev, buf), m);
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else
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bch_cache_set_error(ca->set,
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"%s: too many IO errors %s",
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bdevname(ca->bdev, buf), m);
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}
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}
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void bch_bbio_count_io_errors(struct cache_set *c, struct bio *bio,
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int error, const char *m)
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{
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struct bbio *b = container_of(bio, struct bbio, bio);
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struct cache *ca = PTR_CACHE(c, &b->key, 0);
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unsigned threshold = op_is_write(bio_op(bio))
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? c->congested_write_threshold_us
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: c->congested_read_threshold_us;
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if (threshold) {
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unsigned t = local_clock_us();
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int us = t - b->submit_time_us;
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int congested = atomic_read(&c->congested);
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if (us > (int) threshold) {
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int ms = us / 1024;
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c->congested_last_us = t;
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ms = min(ms, CONGESTED_MAX + congested);
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atomic_sub(ms, &c->congested);
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} else if (congested < 0)
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atomic_inc(&c->congested);
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}
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bch_count_io_errors(ca, error, m);
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}
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void bch_bbio_endio(struct cache_set *c, struct bio *bio,
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int error, const char *m)
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{
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struct closure *cl = bio->bi_private;
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bch_bbio_count_io_errors(c, bio, error, m);
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bio_put(bio);
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closure_put(cl);
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}
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