diff options
Diffstat (limited to 'drivers/md/bcache/io.c')
| -rw-r--r-- | drivers/md/bcache/io.c | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/drivers/md/bcache/io.c b/drivers/md/bcache/io.c new file mode 100644 index 000000000..dad71a6b7 --- /dev/null +++ b/drivers/md/bcache/io.c @@ -0,0 +1,174 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Some low level IO code, and hacks for various block layer limitations + * + * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com> + * Copyright 2012 Google, Inc. + */ + +#include "bcache.h" +#include "bset.h" +#include "debug.h" + +#include <linux/blkdev.h> + +/* Bios with headers */ + +void bch_bbio_free(struct bio *bio, struct cache_set *c) +{ + struct bbio *b = container_of(bio, struct bbio, bio); + + mempool_free(b, &c->bio_meta); +} + +struct bio *bch_bbio_alloc(struct cache_set *c) +{ + struct bbio *b = mempool_alloc(&c->bio_meta, GFP_NOIO); + struct bio *bio = &b->bio; + + bio_init(bio, bio->bi_inline_vecs, meta_bucket_pages(&c->cache->sb)); + + return bio; +} + +void __bch_submit_bbio(struct bio *bio, struct cache_set *c) +{ + struct bbio *b = container_of(bio, struct bbio, bio); + + bio->bi_iter.bi_sector = PTR_OFFSET(&b->key, 0); + bio_set_dev(bio, PTR_CACHE(c, &b->key, 0)->bdev); + + b->submit_time_us = local_clock_us(); + closure_bio_submit(c, bio, bio->bi_private); +} + +void bch_submit_bbio(struct bio *bio, struct cache_set *c, + struct bkey *k, unsigned int ptr) +{ + struct bbio *b = container_of(bio, struct bbio, bio); + + bch_bkey_copy_single_ptr(&b->key, k, ptr); + __bch_submit_bbio(bio, c); +} + +/* IO errors */ +void bch_count_backing_io_errors(struct cached_dev *dc, struct bio *bio) +{ + unsigned int errors; + + WARN_ONCE(!dc, "NULL pointer of struct cached_dev"); + + /* + * Read-ahead requests on a degrading and recovering md raid + * (e.g. raid6) device might be failured immediately by md + * raid code, which is not a real hardware media failure. So + * we shouldn't count failed REQ_RAHEAD bio to dc->io_errors. + */ + if (bio->bi_opf & REQ_RAHEAD) { + pr_warn_ratelimited("%s: Read-ahead I/O failed on backing device, ignore\n", + dc->backing_dev_name); + return; + } + + errors = atomic_add_return(1, &dc->io_errors); + if (errors < dc->error_limit) + pr_err("%s: IO error on backing device, unrecoverable\n", + dc->backing_dev_name); + else + bch_cached_dev_error(dc); +} + +void bch_count_io_errors(struct cache *ca, + blk_status_t error, + int is_read, + const char *m) +{ + /* + * The halflife of an error is: + * log2(1/2)/log2(127/128) * refresh ~= 88 * refresh + */ + + if (ca->set->error_decay) { + unsigned int count = atomic_inc_return(&ca->io_count); + + while (count > ca->set->error_decay) { + unsigned int errors; + unsigned int old = count; + unsigned int new = count - ca->set->error_decay; + + /* + * First we subtract refresh from count; each time we + * successfully do so, we rescale the errors once: + */ + + count = atomic_cmpxchg(&ca->io_count, old, new); + + if (count == old) { + count = new; + + errors = atomic_read(&ca->io_errors); + do { + old = errors; + new = ((uint64_t) errors * 127) / 128; + errors = atomic_cmpxchg(&ca->io_errors, + old, new); + } while (old != errors); + } + } + } + + if (error) { + unsigned int errors = atomic_add_return(1 << IO_ERROR_SHIFT, + &ca->io_errors); + errors >>= IO_ERROR_SHIFT; + + if (errors < ca->set->error_limit) + pr_err("%s: IO error on %s%s\n", + ca->cache_dev_name, m, + is_read ? ", recovering." : "."); + else + bch_cache_set_error(ca->set, + "%s: too many IO errors %s\n", + ca->cache_dev_name, m); + } +} + +void bch_bbio_count_io_errors(struct cache_set *c, struct bio *bio, + blk_status_t error, const char *m) +{ + struct bbio *b = container_of(bio, struct bbio, bio); + struct cache *ca = PTR_CACHE(c, &b->key, 0); + int is_read = (bio_data_dir(bio) == READ ? 1 : 0); + + unsigned int threshold = op_is_write(bio_op(bio)) + ? c->congested_write_threshold_us + : c->congested_read_threshold_us; + + if (threshold) { + unsigned int t = local_clock_us(); + int us = t - b->submit_time_us; + int congested = atomic_read(&c->congested); + + if (us > (int) threshold) { + int ms = us / 1024; + + c->congested_last_us = t; + + ms = min(ms, CONGESTED_MAX + congested); + atomic_sub(ms, &c->congested); + } else if (congested < 0) + atomic_inc(&c->congested); + } + + bch_count_io_errors(ca, error, is_read, m); +} + +void bch_bbio_endio(struct cache_set *c, struct bio *bio, + blk_status_t error, const char *m) +{ + struct closure *cl = bio->bi_private; + + bch_bbio_count_io_errors(c, bio, error, m); + bio_put(bio); + closure_put(cl); +} |