![Kent Overstreet](/assets/img/avatar_default.png)
More testing ftw! Also, now verify mode doesn't break if you read dirty data. Signed-off-by: Kent Overstreet <kmo@daterainc.com>
1339 lines
32 KiB
C
1339 lines
32 KiB
C
/*
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* Main bcache entry point - handle a read or a write request and decide what to
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* do with it; the make_request functions are called by the block layer.
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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 "btree.h"
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#include "debug.h"
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#include "request.h"
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#include "writeback.h"
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#include <linux/cgroup.h>
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#include <linux/module.h>
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#include <linux/hash.h>
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#include <linux/random.h>
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#include "blk-cgroup.h"
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#include <trace/events/bcache.h>
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#define CUTOFF_CACHE_ADD 95
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#define CUTOFF_CACHE_READA 90
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struct kmem_cache *bch_search_cache;
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static void bch_data_insert_start(struct closure *);
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/* Cgroup interface */
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#ifdef CONFIG_CGROUP_BCACHE
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static struct bch_cgroup bcache_default_cgroup = { .cache_mode = -1 };
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static struct bch_cgroup *cgroup_to_bcache(struct cgroup *cgroup)
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{
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struct cgroup_subsys_state *css;
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return cgroup &&
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(css = cgroup_subsys_state(cgroup, bcache_subsys_id))
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? container_of(css, struct bch_cgroup, css)
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: &bcache_default_cgroup;
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}
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struct bch_cgroup *bch_bio_to_cgroup(struct bio *bio)
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{
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struct cgroup_subsys_state *css = bio->bi_css
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? cgroup_subsys_state(bio->bi_css->cgroup, bcache_subsys_id)
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: task_subsys_state(current, bcache_subsys_id);
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return css
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? container_of(css, struct bch_cgroup, css)
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: &bcache_default_cgroup;
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}
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static ssize_t cache_mode_read(struct cgroup *cgrp, struct cftype *cft,
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struct file *file,
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char __user *buf, size_t nbytes, loff_t *ppos)
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{
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char tmp[1024];
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int len = bch_snprint_string_list(tmp, PAGE_SIZE, bch_cache_modes,
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cgroup_to_bcache(cgrp)->cache_mode + 1);
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if (len < 0)
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return len;
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return simple_read_from_buffer(buf, nbytes, ppos, tmp, len);
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}
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static int cache_mode_write(struct cgroup *cgrp, struct cftype *cft,
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const char *buf)
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{
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int v = bch_read_string_list(buf, bch_cache_modes);
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if (v < 0)
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return v;
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cgroup_to_bcache(cgrp)->cache_mode = v - 1;
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return 0;
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}
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static u64 bch_verify_read(struct cgroup *cgrp, struct cftype *cft)
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{
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return cgroup_to_bcache(cgrp)->verify;
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}
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static int bch_verify_write(struct cgroup *cgrp, struct cftype *cft, u64 val)
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{
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cgroup_to_bcache(cgrp)->verify = val;
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return 0;
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}
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static u64 bch_cache_hits_read(struct cgroup *cgrp, struct cftype *cft)
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{
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struct bch_cgroup *bcachecg = cgroup_to_bcache(cgrp);
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return atomic_read(&bcachecg->stats.cache_hits);
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}
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static u64 bch_cache_misses_read(struct cgroup *cgrp, struct cftype *cft)
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{
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struct bch_cgroup *bcachecg = cgroup_to_bcache(cgrp);
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return atomic_read(&bcachecg->stats.cache_misses);
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}
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static u64 bch_cache_bypass_hits_read(struct cgroup *cgrp,
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struct cftype *cft)
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{
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struct bch_cgroup *bcachecg = cgroup_to_bcache(cgrp);
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return atomic_read(&bcachecg->stats.cache_bypass_hits);
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}
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static u64 bch_cache_bypass_misses_read(struct cgroup *cgrp,
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struct cftype *cft)
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{
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struct bch_cgroup *bcachecg = cgroup_to_bcache(cgrp);
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return atomic_read(&bcachecg->stats.cache_bypass_misses);
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}
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static struct cftype bch_files[] = {
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{
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.name = "cache_mode",
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.read = cache_mode_read,
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.write_string = cache_mode_write,
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},
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{
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.name = "verify",
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.read_u64 = bch_verify_read,
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.write_u64 = bch_verify_write,
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},
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{
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.name = "cache_hits",
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.read_u64 = bch_cache_hits_read,
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},
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{
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.name = "cache_misses",
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.read_u64 = bch_cache_misses_read,
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},
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{
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.name = "cache_bypass_hits",
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.read_u64 = bch_cache_bypass_hits_read,
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},
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{
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.name = "cache_bypass_misses",
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.read_u64 = bch_cache_bypass_misses_read,
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},
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{ } /* terminate */
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};
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static void init_bch_cgroup(struct bch_cgroup *cg)
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{
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cg->cache_mode = -1;
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}
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static struct cgroup_subsys_state *bcachecg_create(struct cgroup *cgroup)
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{
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struct bch_cgroup *cg;
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cg = kzalloc(sizeof(*cg), GFP_KERNEL);
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if (!cg)
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return ERR_PTR(-ENOMEM);
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init_bch_cgroup(cg);
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return &cg->css;
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}
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static void bcachecg_destroy(struct cgroup *cgroup)
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{
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struct bch_cgroup *cg = cgroup_to_bcache(cgroup);
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free_css_id(&bcache_subsys, &cg->css);
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kfree(cg);
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}
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struct cgroup_subsys bcache_subsys = {
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.create = bcachecg_create,
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.destroy = bcachecg_destroy,
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.subsys_id = bcache_subsys_id,
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.name = "bcache",
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.module = THIS_MODULE,
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};
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EXPORT_SYMBOL_GPL(bcache_subsys);
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#endif
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static unsigned cache_mode(struct cached_dev *dc, struct bio *bio)
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{
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#ifdef CONFIG_CGROUP_BCACHE
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int r = bch_bio_to_cgroup(bio)->cache_mode;
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if (r >= 0)
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return r;
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#endif
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return BDEV_CACHE_MODE(&dc->sb);
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}
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static bool verify(struct cached_dev *dc, struct bio *bio)
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{
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#ifdef CONFIG_CGROUP_BCACHE
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if (bch_bio_to_cgroup(bio)->verify)
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return true;
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#endif
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return dc->verify;
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}
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static void bio_csum(struct bio *bio, struct bkey *k)
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{
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struct bio_vec *bv;
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uint64_t csum = 0;
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int i;
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bio_for_each_segment(bv, bio, i) {
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void *d = kmap(bv->bv_page) + bv->bv_offset;
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csum = bch_crc64_update(csum, d, bv->bv_len);
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kunmap(bv->bv_page);
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}
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k->ptr[KEY_PTRS(k)] = csum & (~0ULL >> 1);
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}
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/* Insert data into cache */
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static void bch_data_insert_keys(struct closure *cl)
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{
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struct data_insert_op *op = container_of(cl, struct data_insert_op, cl);
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atomic_t *journal_ref = NULL;
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struct bkey *replace_key = op->replace ? &op->replace_key : NULL;
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int ret;
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/*
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* If we're looping, might already be waiting on
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* another journal write - can't wait on more than one journal write at
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* a time
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*
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* XXX: this looks wrong
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*/
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#if 0
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while (atomic_read(&s->cl.remaining) & CLOSURE_WAITING)
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closure_sync(&s->cl);
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#endif
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if (!op->replace)
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journal_ref = bch_journal(op->c, &op->insert_keys,
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op->flush_journal ? cl : NULL);
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ret = bch_btree_insert(op->c, &op->insert_keys,
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journal_ref, replace_key);
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if (ret == -ESRCH) {
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op->replace_collision = true;
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} else if (ret) {
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op->error = -ENOMEM;
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op->insert_data_done = true;
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}
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if (journal_ref)
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atomic_dec_bug(journal_ref);
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if (!op->insert_data_done)
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continue_at(cl, bch_data_insert_start, bcache_wq);
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bch_keylist_free(&op->insert_keys);
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closure_return(cl);
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}
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static void bch_data_invalidate(struct closure *cl)
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{
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struct data_insert_op *op = container_of(cl, struct data_insert_op, cl);
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struct bio *bio = op->bio;
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pr_debug("invalidating %i sectors from %llu",
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bio_sectors(bio), (uint64_t) bio->bi_sector);
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while (bio_sectors(bio)) {
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unsigned sectors = min(bio_sectors(bio),
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1U << (KEY_SIZE_BITS - 1));
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if (bch_keylist_realloc(&op->insert_keys, 0, op->c))
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goto out;
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bio->bi_sector += sectors;
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bio->bi_size -= sectors << 9;
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bch_keylist_add(&op->insert_keys,
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&KEY(op->inode, bio->bi_sector, sectors));
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}
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op->insert_data_done = true;
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bio_put(bio);
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out:
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continue_at(cl, bch_data_insert_keys, bcache_wq);
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}
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static void bch_data_insert_error(struct closure *cl)
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{
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struct data_insert_op *op = container_of(cl, struct data_insert_op, cl);
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/*
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* Our data write just errored, which means we've got a bunch of keys to
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* insert that point to data that wasn't succesfully written.
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*
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* We don't have to insert those keys but we still have to invalidate
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* that region of the cache - so, if we just strip off all the pointers
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* from the keys we'll accomplish just that.
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*/
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struct bkey *src = op->insert_keys.keys, *dst = op->insert_keys.keys;
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while (src != op->insert_keys.top) {
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struct bkey *n = bkey_next(src);
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SET_KEY_PTRS(src, 0);
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memmove(dst, src, bkey_bytes(src));
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dst = bkey_next(dst);
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src = n;
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}
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op->insert_keys.top = dst;
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bch_data_insert_keys(cl);
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}
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static void bch_data_insert_endio(struct bio *bio, int error)
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{
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struct closure *cl = bio->bi_private;
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struct data_insert_op *op = container_of(cl, struct data_insert_op, cl);
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if (error) {
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/* TODO: We could try to recover from this. */
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if (op->writeback)
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op->error = error;
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else if (!op->replace)
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set_closure_fn(cl, bch_data_insert_error, bcache_wq);
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else
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set_closure_fn(cl, NULL, NULL);
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}
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bch_bbio_endio(op->c, bio, error, "writing data to cache");
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}
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static void bch_data_insert_start(struct closure *cl)
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{
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struct data_insert_op *op = container_of(cl, struct data_insert_op, cl);
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struct bio *bio = op->bio, *n;
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if (op->bypass)
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return bch_data_invalidate(cl);
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if (atomic_sub_return(bio_sectors(bio), &op->c->sectors_to_gc) < 0) {
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set_gc_sectors(op->c);
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wake_up_gc(op->c);
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}
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/*
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* Journal writes are marked REQ_FLUSH; if the original write was a
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* flush, it'll wait on the journal write.
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*/
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bio->bi_rw &= ~(REQ_FLUSH|REQ_FUA);
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do {
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unsigned i;
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struct bkey *k;
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struct bio_set *split = op->c->bio_split;
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/* 1 for the device pointer and 1 for the chksum */
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if (bch_keylist_realloc(&op->insert_keys,
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1 + (op->csum ? 1 : 0),
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op->c))
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continue_at(cl, bch_data_insert_keys, bcache_wq);
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k = op->insert_keys.top;
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bkey_init(k);
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SET_KEY_INODE(k, op->inode);
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SET_KEY_OFFSET(k, bio->bi_sector);
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if (!bch_alloc_sectors(op->c, k, bio_sectors(bio),
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op->write_point, op->write_prio,
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op->writeback))
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goto err;
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n = bch_bio_split(bio, KEY_SIZE(k), GFP_NOIO, split);
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n->bi_end_io = bch_data_insert_endio;
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n->bi_private = cl;
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if (op->writeback) {
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SET_KEY_DIRTY(k, true);
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for (i = 0; i < KEY_PTRS(k); i++)
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SET_GC_MARK(PTR_BUCKET(op->c, k, i),
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GC_MARK_DIRTY);
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}
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SET_KEY_CSUM(k, op->csum);
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if (KEY_CSUM(k))
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bio_csum(n, k);
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trace_bcache_cache_insert(k);
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bch_keylist_push(&op->insert_keys);
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n->bi_rw |= REQ_WRITE;
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bch_submit_bbio(n, op->c, k, 0);
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} while (n != bio);
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op->insert_data_done = true;
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continue_at(cl, bch_data_insert_keys, bcache_wq);
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err:
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/* bch_alloc_sectors() blocks if s->writeback = true */
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BUG_ON(op->writeback);
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/*
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* But if it's not a writeback write we'd rather just bail out if
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* there aren't any buckets ready to write to - it might take awhile and
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* we might be starving btree writes for gc or something.
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*/
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if (!op->replace) {
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/*
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* Writethrough write: We can't complete the write until we've
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* updated the index. But we don't want to delay the write while
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* we wait for buckets to be freed up, so just invalidate the
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* rest of the write.
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*/
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op->bypass = true;
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return bch_data_invalidate(cl);
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} else {
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/*
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* From a cache miss, we can just insert the keys for the data
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* we have written or bail out if we didn't do anything.
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*/
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op->insert_data_done = true;
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bio_put(bio);
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if (!bch_keylist_empty(&op->insert_keys))
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continue_at(cl, bch_data_insert_keys, bcache_wq);
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else
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closure_return(cl);
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}
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}
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/**
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* bch_data_insert - stick some data in the cache
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*
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* This is the starting point for any data to end up in a cache device; it could
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* be from a normal write, or a writeback write, or a write to a flash only
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* volume - it's also used by the moving garbage collector to compact data in
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* mostly empty buckets.
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*
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* It first writes the data to the cache, creating a list of keys to be inserted
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* (if the data had to be fragmented there will be multiple keys); after the
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* data is written it calls bch_journal, and after the keys have been added to
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* the next journal write they're inserted into the btree.
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*
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* It inserts the data in s->cache_bio; bi_sector is used for the key offset,
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* and op->inode is used for the key inode.
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*
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* If s->bypass is true, instead of inserting the data it invalidates the
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* region of the cache represented by s->cache_bio and op->inode.
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*/
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void bch_data_insert(struct closure *cl)
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{
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struct data_insert_op *op = container_of(cl, struct data_insert_op, cl);
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trace_bcache_write(op->bio, op->writeback, op->bypass);
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bch_keylist_init(&op->insert_keys);
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bio_get(op->bio);
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bch_data_insert_start(cl);
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}
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|
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/* Congested? */
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|
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unsigned bch_get_congested(struct cache_set *c)
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{
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int i;
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long rand;
|
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if (!c->congested_read_threshold_us &&
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!c->congested_write_threshold_us)
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return 0;
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i = (local_clock_us() - c->congested_last_us) / 1024;
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if (i < 0)
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return 0;
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i += atomic_read(&c->congested);
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if (i >= 0)
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return 0;
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i += CONGESTED_MAX;
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if (i > 0)
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i = fract_exp_two(i, 6);
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rand = get_random_int();
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i -= bitmap_weight(&rand, BITS_PER_LONG);
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return i > 0 ? i : 1;
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}
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|
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static void add_sequential(struct task_struct *t)
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{
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ewma_add(t->sequential_io_avg,
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t->sequential_io, 8, 0);
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t->sequential_io = 0;
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}
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|
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static struct hlist_head *iohash(struct cached_dev *dc, uint64_t k)
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{
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return &dc->io_hash[hash_64(k, RECENT_IO_BITS)];
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}
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|
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static bool check_should_bypass(struct cached_dev *dc, struct bio *bio)
|
|
{
|
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struct cache_set *c = dc->disk.c;
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unsigned mode = cache_mode(dc, bio);
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|
unsigned sectors, congested = bch_get_congested(c);
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|
struct task_struct *task = current;
|
|
struct io *i;
|
|
|
|
if (test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) ||
|
|
c->gc_stats.in_use > CUTOFF_CACHE_ADD ||
|
|
(bio->bi_rw & REQ_DISCARD))
|
|
goto skip;
|
|
|
|
if (mode == CACHE_MODE_NONE ||
|
|
(mode == CACHE_MODE_WRITEAROUND &&
|
|
(bio->bi_rw & REQ_WRITE)))
|
|
goto skip;
|
|
|
|
if (bio->bi_sector & (c->sb.block_size - 1) ||
|
|
bio_sectors(bio) & (c->sb.block_size - 1)) {
|
|
pr_debug("skipping unaligned io");
|
|
goto skip;
|
|
}
|
|
|
|
if (bypass_torture_test(dc)) {
|
|
if ((get_random_int() & 3) == 3)
|
|
goto skip;
|
|
else
|
|
goto rescale;
|
|
}
|
|
|
|
if (!congested && !dc->sequential_cutoff)
|
|
goto rescale;
|
|
|
|
if (!congested &&
|
|
mode == CACHE_MODE_WRITEBACK &&
|
|
(bio->bi_rw & REQ_WRITE) &&
|
|
(bio->bi_rw & REQ_SYNC))
|
|
goto rescale;
|
|
|
|
spin_lock(&dc->io_lock);
|
|
|
|
hlist_for_each_entry(i, iohash(dc, bio->bi_sector), hash)
|
|
if (i->last == bio->bi_sector &&
|
|
time_before(jiffies, i->jiffies))
|
|
goto found;
|
|
|
|
i = list_first_entry(&dc->io_lru, struct io, lru);
|
|
|
|
add_sequential(task);
|
|
i->sequential = 0;
|
|
found:
|
|
if (i->sequential + bio->bi_size > i->sequential)
|
|
i->sequential += bio->bi_size;
|
|
|
|
i->last = bio_end_sector(bio);
|
|
i->jiffies = jiffies + msecs_to_jiffies(5000);
|
|
task->sequential_io = i->sequential;
|
|
|
|
hlist_del(&i->hash);
|
|
hlist_add_head(&i->hash, iohash(dc, i->last));
|
|
list_move_tail(&i->lru, &dc->io_lru);
|
|
|
|
spin_unlock(&dc->io_lock);
|
|
|
|
sectors = max(task->sequential_io,
|
|
task->sequential_io_avg) >> 9;
|
|
|
|
if (dc->sequential_cutoff &&
|
|
sectors >= dc->sequential_cutoff >> 9) {
|
|
trace_bcache_bypass_sequential(bio);
|
|
goto skip;
|
|
}
|
|
|
|
if (congested && sectors >= congested) {
|
|
trace_bcache_bypass_congested(bio);
|
|
goto skip;
|
|
}
|
|
|
|
rescale:
|
|
bch_rescale_priorities(c, bio_sectors(bio));
|
|
return false;
|
|
skip:
|
|
bch_mark_sectors_bypassed(c, dc, bio_sectors(bio));
|
|
return true;
|
|
}
|
|
|
|
/* Cache lookup */
|
|
|
|
struct search {
|
|
/* Stack frame for bio_complete */
|
|
struct closure cl;
|
|
|
|
struct bcache_device *d;
|
|
|
|
struct bbio bio;
|
|
struct bio *orig_bio;
|
|
struct bio *cache_miss;
|
|
|
|
unsigned insert_bio_sectors;
|
|
|
|
unsigned recoverable:1;
|
|
unsigned unaligned_bvec:1;
|
|
unsigned write:1;
|
|
unsigned read_dirty_data:1;
|
|
|
|
unsigned long start_time;
|
|
|
|
struct btree_op op;
|
|
struct data_insert_op iop;
|
|
};
|
|
|
|
static void bch_cache_read_endio(struct bio *bio, int error)
|
|
{
|
|
struct bbio *b = container_of(bio, struct bbio, bio);
|
|
struct closure *cl = bio->bi_private;
|
|
struct search *s = container_of(cl, struct search, cl);
|
|
|
|
/*
|
|
* If the bucket was reused while our bio was in flight, we might have
|
|
* read the wrong data. Set s->error but not error so it doesn't get
|
|
* counted against the cache device, but we'll still reread the data
|
|
* from the backing device.
|
|
*/
|
|
|
|
if (error)
|
|
s->iop.error = error;
|
|
else if (ptr_stale(s->iop.c, &b->key, 0)) {
|
|
atomic_long_inc(&s->iop.c->cache_read_races);
|
|
s->iop.error = -EINTR;
|
|
}
|
|
|
|
bch_bbio_endio(s->iop.c, bio, error, "reading from cache");
|
|
}
|
|
|
|
/*
|
|
* Read from a single key, handling the initial cache miss if the key starts in
|
|
* the middle of the bio
|
|
*/
|
|
static int cache_lookup_fn(struct btree_op *op, struct btree *b, struct bkey *k)
|
|
{
|
|
struct search *s = container_of(op, struct search, op);
|
|
struct bio *n, *bio = &s->bio.bio;
|
|
struct bkey *bio_key;
|
|
unsigned ptr;
|
|
|
|
if (bkey_cmp(k, &KEY(s->iop.inode, bio->bi_sector, 0)) <= 0)
|
|
return MAP_CONTINUE;
|
|
|
|
if (KEY_INODE(k) != s->iop.inode ||
|
|
KEY_START(k) > bio->bi_sector) {
|
|
unsigned bio_sectors = bio_sectors(bio);
|
|
unsigned sectors = KEY_INODE(k) == s->iop.inode
|
|
? min_t(uint64_t, INT_MAX,
|
|
KEY_START(k) - bio->bi_sector)
|
|
: INT_MAX;
|
|
|
|
int ret = s->d->cache_miss(b, s, bio, sectors);
|
|
if (ret != MAP_CONTINUE)
|
|
return ret;
|
|
|
|
/* if this was a complete miss we shouldn't get here */
|
|
BUG_ON(bio_sectors <= sectors);
|
|
}
|
|
|
|
if (!KEY_SIZE(k))
|
|
return MAP_CONTINUE;
|
|
|
|
/* XXX: figure out best pointer - for multiple cache devices */
|
|
ptr = 0;
|
|
|
|
PTR_BUCKET(b->c, k, ptr)->prio = INITIAL_PRIO;
|
|
|
|
if (KEY_DIRTY(k))
|
|
s->read_dirty_data = true;
|
|
|
|
n = bch_bio_split(bio, min_t(uint64_t, INT_MAX,
|
|
KEY_OFFSET(k) - bio->bi_sector),
|
|
GFP_NOIO, s->d->bio_split);
|
|
|
|
bio_key = &container_of(n, struct bbio, bio)->key;
|
|
bch_bkey_copy_single_ptr(bio_key, k, ptr);
|
|
|
|
bch_cut_front(&KEY(s->iop.inode, n->bi_sector, 0), bio_key);
|
|
bch_cut_back(&KEY(s->iop.inode, bio_end_sector(n), 0), bio_key);
|
|
|
|
n->bi_end_io = bch_cache_read_endio;
|
|
n->bi_private = &s->cl;
|
|
|
|
/*
|
|
* The bucket we're reading from might be reused while our bio
|
|
* is in flight, and we could then end up reading the wrong
|
|
* data.
|
|
*
|
|
* We guard against this by checking (in cache_read_endio()) if
|
|
* the pointer is stale again; if so, we treat it as an error
|
|
* and reread from the backing device (but we don't pass that
|
|
* error up anywhere).
|
|
*/
|
|
|
|
__bch_submit_bbio(n, b->c);
|
|
return n == bio ? MAP_DONE : MAP_CONTINUE;
|
|
}
|
|
|
|
static void cache_lookup(struct closure *cl)
|
|
{
|
|
struct search *s = container_of(cl, struct search, iop.cl);
|
|
struct bio *bio = &s->bio.bio;
|
|
|
|
int ret = bch_btree_map_keys(&s->op, s->iop.c,
|
|
&KEY(s->iop.inode, bio->bi_sector, 0),
|
|
cache_lookup_fn, MAP_END_KEY);
|
|
if (ret == -EAGAIN)
|
|
continue_at(cl, cache_lookup, bcache_wq);
|
|
|
|
closure_return(cl);
|
|
}
|
|
|
|
/* Common code for the make_request functions */
|
|
|
|
static void request_endio(struct bio *bio, int error)
|
|
{
|
|
struct closure *cl = bio->bi_private;
|
|
|
|
if (error) {
|
|
struct search *s = container_of(cl, struct search, cl);
|
|
s->iop.error = error;
|
|
/* Only cache read errors are recoverable */
|
|
s->recoverable = false;
|
|
}
|
|
|
|
bio_put(bio);
|
|
closure_put(cl);
|
|
}
|
|
|
|
static void bio_complete(struct search *s)
|
|
{
|
|
if (s->orig_bio) {
|
|
int cpu, rw = bio_data_dir(s->orig_bio);
|
|
unsigned long duration = jiffies - s->start_time;
|
|
|
|
cpu = part_stat_lock();
|
|
part_round_stats(cpu, &s->d->disk->part0);
|
|
part_stat_add(cpu, &s->d->disk->part0, ticks[rw], duration);
|
|
part_stat_unlock();
|
|
|
|
trace_bcache_request_end(s->d, s->orig_bio);
|
|
bio_endio(s->orig_bio, s->iop.error);
|
|
s->orig_bio = NULL;
|
|
}
|
|
}
|
|
|
|
static void do_bio_hook(struct search *s)
|
|
{
|
|
struct bio *bio = &s->bio.bio;
|
|
memcpy(bio, s->orig_bio, sizeof(struct bio));
|
|
|
|
bio->bi_end_io = request_endio;
|
|
bio->bi_private = &s->cl;
|
|
atomic_set(&bio->bi_cnt, 3);
|
|
}
|
|
|
|
static void search_free(struct closure *cl)
|
|
{
|
|
struct search *s = container_of(cl, struct search, cl);
|
|
bio_complete(s);
|
|
|
|
if (s->iop.bio)
|
|
bio_put(s->iop.bio);
|
|
|
|
if (s->unaligned_bvec)
|
|
mempool_free(s->bio.bio.bi_io_vec, s->d->unaligned_bvec);
|
|
|
|
closure_debug_destroy(cl);
|
|
mempool_free(s, s->d->c->search);
|
|
}
|
|
|
|
static struct search *search_alloc(struct bio *bio, struct bcache_device *d)
|
|
{
|
|
struct search *s;
|
|
struct bio_vec *bv;
|
|
|
|
s = mempool_alloc(d->c->search, GFP_NOIO);
|
|
memset(s, 0, offsetof(struct search, iop.insert_keys));
|
|
|
|
__closure_init(&s->cl, NULL);
|
|
|
|
s->iop.inode = d->id;
|
|
s->iop.c = d->c;
|
|
s->d = d;
|
|
s->op.lock = -1;
|
|
s->iop.write_point = hash_long((unsigned long) current, 16);
|
|
s->orig_bio = bio;
|
|
s->write = (bio->bi_rw & REQ_WRITE) != 0;
|
|
s->iop.flush_journal = (bio->bi_rw & (REQ_FLUSH|REQ_FUA)) != 0;
|
|
s->recoverable = 1;
|
|
s->start_time = jiffies;
|
|
do_bio_hook(s);
|
|
|
|
if (bio->bi_size != bio_segments(bio) * PAGE_SIZE) {
|
|
bv = mempool_alloc(d->unaligned_bvec, GFP_NOIO);
|
|
memcpy(bv, bio_iovec(bio),
|
|
sizeof(struct bio_vec) * bio_segments(bio));
|
|
|
|
s->bio.bio.bi_io_vec = bv;
|
|
s->unaligned_bvec = 1;
|
|
}
|
|
|
|
return s;
|
|
}
|
|
|
|
/* Cached devices */
|
|
|
|
static void cached_dev_bio_complete(struct closure *cl)
|
|
{
|
|
struct search *s = container_of(cl, struct search, cl);
|
|
struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
|
|
|
|
search_free(cl);
|
|
cached_dev_put(dc);
|
|
}
|
|
|
|
/* Process reads */
|
|
|
|
static void cached_dev_cache_miss_done(struct closure *cl)
|
|
{
|
|
struct search *s = container_of(cl, struct search, cl);
|
|
|
|
if (s->iop.replace_collision)
|
|
bch_mark_cache_miss_collision(s->iop.c, s->d);
|
|
|
|
if (s->iop.bio) {
|
|
int i;
|
|
struct bio_vec *bv;
|
|
|
|
bio_for_each_segment_all(bv, s->iop.bio, i)
|
|
__free_page(bv->bv_page);
|
|
}
|
|
|
|
cached_dev_bio_complete(cl);
|
|
}
|
|
|
|
static void cached_dev_read_error(struct closure *cl)
|
|
{
|
|
struct search *s = container_of(cl, struct search, cl);
|
|
struct bio *bio = &s->bio.bio;
|
|
struct bio_vec *bv;
|
|
int i;
|
|
|
|
if (s->recoverable) {
|
|
/* Retry from the backing device: */
|
|
trace_bcache_read_retry(s->orig_bio);
|
|
|
|
s->iop.error = 0;
|
|
bv = s->bio.bio.bi_io_vec;
|
|
do_bio_hook(s);
|
|
s->bio.bio.bi_io_vec = bv;
|
|
|
|
if (!s->unaligned_bvec)
|
|
bio_for_each_segment(bv, s->orig_bio, i)
|
|
bv->bv_offset = 0, bv->bv_len = PAGE_SIZE;
|
|
else
|
|
memcpy(s->bio.bio.bi_io_vec,
|
|
bio_iovec(s->orig_bio),
|
|
sizeof(struct bio_vec) *
|
|
bio_segments(s->orig_bio));
|
|
|
|
/* XXX: invalidate cache */
|
|
|
|
closure_bio_submit(bio, cl, s->d);
|
|
}
|
|
|
|
continue_at(cl, cached_dev_cache_miss_done, NULL);
|
|
}
|
|
|
|
static void cached_dev_read_done(struct closure *cl)
|
|
{
|
|
struct search *s = container_of(cl, struct search, cl);
|
|
struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
|
|
|
|
/*
|
|
* We had a cache miss; cache_bio now contains data ready to be inserted
|
|
* into the cache.
|
|
*
|
|
* First, we copy the data we just read from cache_bio's bounce buffers
|
|
* to the buffers the original bio pointed to:
|
|
*/
|
|
|
|
if (s->iop.bio) {
|
|
bio_reset(s->iop.bio);
|
|
s->iop.bio->bi_sector = s->cache_miss->bi_sector;
|
|
s->iop.bio->bi_bdev = s->cache_miss->bi_bdev;
|
|
s->iop.bio->bi_size = s->insert_bio_sectors << 9;
|
|
bch_bio_map(s->iop.bio, NULL);
|
|
|
|
bio_copy_data(s->cache_miss, s->iop.bio);
|
|
|
|
bio_put(s->cache_miss);
|
|
s->cache_miss = NULL;
|
|
}
|
|
|
|
if (verify(dc, &s->bio.bio) && s->recoverable &&
|
|
!s->unaligned_bvec && !s->read_dirty_data)
|
|
bch_data_verify(dc, s->orig_bio);
|
|
|
|
bio_complete(s);
|
|
|
|
if (s->iop.bio &&
|
|
!test_bit(CACHE_SET_STOPPING, &s->iop.c->flags)) {
|
|
BUG_ON(!s->iop.replace);
|
|
closure_call(&s->iop.cl, bch_data_insert, NULL, cl);
|
|
}
|
|
|
|
continue_at(cl, cached_dev_cache_miss_done, NULL);
|
|
}
|
|
|
|
static void cached_dev_read_done_bh(struct closure *cl)
|
|
{
|
|
struct search *s = container_of(cl, struct search, cl);
|
|
struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
|
|
|
|
bch_mark_cache_accounting(s->iop.c, s->d,
|
|
!s->cache_miss, s->iop.bypass);
|
|
trace_bcache_read(s->orig_bio, !s->cache_miss, s->iop.bypass);
|
|
|
|
if (s->iop.error)
|
|
continue_at_nobarrier(cl, cached_dev_read_error, bcache_wq);
|
|
else if (s->iop.bio || verify(dc, &s->bio.bio))
|
|
continue_at_nobarrier(cl, cached_dev_read_done, bcache_wq);
|
|
else
|
|
continue_at_nobarrier(cl, cached_dev_bio_complete, NULL);
|
|
}
|
|
|
|
static int cached_dev_cache_miss(struct btree *b, struct search *s,
|
|
struct bio *bio, unsigned sectors)
|
|
{
|
|
int ret = MAP_CONTINUE;
|
|
unsigned reada = 0;
|
|
struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
|
|
struct bio *miss, *cache_bio;
|
|
|
|
if (s->cache_miss || s->iop.bypass) {
|
|
miss = bch_bio_split(bio, sectors, GFP_NOIO, s->d->bio_split);
|
|
ret = miss == bio ? MAP_DONE : MAP_CONTINUE;
|
|
goto out_submit;
|
|
}
|
|
|
|
if (!(bio->bi_rw & REQ_RAHEAD) &&
|
|
!(bio->bi_rw & REQ_META) &&
|
|
s->iop.c->gc_stats.in_use < CUTOFF_CACHE_READA)
|
|
reada = min_t(sector_t, dc->readahead >> 9,
|
|
bdev_sectors(bio->bi_bdev) - bio_end_sector(bio));
|
|
|
|
s->insert_bio_sectors = min(sectors, bio_sectors(bio) + reada);
|
|
|
|
s->iop.replace_key = KEY(s->iop.inode,
|
|
bio->bi_sector + s->insert_bio_sectors,
|
|
s->insert_bio_sectors);
|
|
|
|
ret = bch_btree_insert_check_key(b, &s->op, &s->iop.replace_key);
|
|
if (ret)
|
|
return ret;
|
|
|
|
s->iop.replace = true;
|
|
|
|
miss = bch_bio_split(bio, sectors, GFP_NOIO, s->d->bio_split);
|
|
|
|
/* btree_search_recurse()'s btree iterator is no good anymore */
|
|
ret = miss == bio ? MAP_DONE : -EINTR;
|
|
|
|
cache_bio = bio_alloc_bioset(GFP_NOWAIT,
|
|
DIV_ROUND_UP(s->insert_bio_sectors, PAGE_SECTORS),
|
|
dc->disk.bio_split);
|
|
if (!cache_bio)
|
|
goto out_submit;
|
|
|
|
cache_bio->bi_sector = miss->bi_sector;
|
|
cache_bio->bi_bdev = miss->bi_bdev;
|
|
cache_bio->bi_size = s->insert_bio_sectors << 9;
|
|
|
|
cache_bio->bi_end_io = request_endio;
|
|
cache_bio->bi_private = &s->cl;
|
|
|
|
bch_bio_map(cache_bio, NULL);
|
|
if (bio_alloc_pages(cache_bio, __GFP_NOWARN|GFP_NOIO))
|
|
goto out_put;
|
|
|
|
if (reada)
|
|
bch_mark_cache_readahead(s->iop.c, s->d);
|
|
|
|
s->cache_miss = miss;
|
|
s->iop.bio = cache_bio;
|
|
bio_get(cache_bio);
|
|
closure_bio_submit(cache_bio, &s->cl, s->d);
|
|
|
|
return ret;
|
|
out_put:
|
|
bio_put(cache_bio);
|
|
out_submit:
|
|
miss->bi_end_io = request_endio;
|
|
miss->bi_private = &s->cl;
|
|
closure_bio_submit(miss, &s->cl, s->d);
|
|
return ret;
|
|
}
|
|
|
|
static void cached_dev_read(struct cached_dev *dc, struct search *s)
|
|
{
|
|
struct closure *cl = &s->cl;
|
|
|
|
closure_call(&s->iop.cl, cache_lookup, NULL, cl);
|
|
continue_at(cl, cached_dev_read_done_bh, NULL);
|
|
}
|
|
|
|
/* Process writes */
|
|
|
|
static void cached_dev_write_complete(struct closure *cl)
|
|
{
|
|
struct search *s = container_of(cl, struct search, cl);
|
|
struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
|
|
|
|
up_read_non_owner(&dc->writeback_lock);
|
|
cached_dev_bio_complete(cl);
|
|
}
|
|
|
|
static void cached_dev_write(struct cached_dev *dc, struct search *s)
|
|
{
|
|
struct closure *cl = &s->cl;
|
|
struct bio *bio = &s->bio.bio;
|
|
struct bkey start = KEY(dc->disk.id, bio->bi_sector, 0);
|
|
struct bkey end = KEY(dc->disk.id, bio_end_sector(bio), 0);
|
|
|
|
bch_keybuf_check_overlapping(&s->iop.c->moving_gc_keys, &start, &end);
|
|
|
|
down_read_non_owner(&dc->writeback_lock);
|
|
if (bch_keybuf_check_overlapping(&dc->writeback_keys, &start, &end)) {
|
|
/*
|
|
* We overlap with some dirty data undergoing background
|
|
* writeback, force this write to writeback
|
|
*/
|
|
s->iop.bypass = false;
|
|
s->iop.writeback = true;
|
|
}
|
|
|
|
/*
|
|
* Discards aren't _required_ to do anything, so skipping if
|
|
* check_overlapping returned true is ok
|
|
*
|
|
* But check_overlapping drops dirty keys for which io hasn't started,
|
|
* so we still want to call it.
|
|
*/
|
|
if (bio->bi_rw & REQ_DISCARD)
|
|
s->iop.bypass = true;
|
|
|
|
if (should_writeback(dc, s->orig_bio,
|
|
cache_mode(dc, bio),
|
|
s->iop.bypass)) {
|
|
s->iop.bypass = false;
|
|
s->iop.writeback = true;
|
|
}
|
|
|
|
if (s->iop.bypass) {
|
|
s->iop.bio = s->orig_bio;
|
|
bio_get(s->iop.bio);
|
|
|
|
if (!(bio->bi_rw & REQ_DISCARD) ||
|
|
blk_queue_discard(bdev_get_queue(dc->bdev)))
|
|
closure_bio_submit(bio, cl, s->d);
|
|
} else if (s->iop.writeback) {
|
|
bch_writeback_add(dc);
|
|
s->iop.bio = bio;
|
|
|
|
if (bio->bi_rw & REQ_FLUSH) {
|
|
/* Also need to send a flush to the backing device */
|
|
struct bio *flush = bio_alloc_bioset(GFP_NOIO, 0,
|
|
dc->disk.bio_split);
|
|
|
|
flush->bi_rw = WRITE_FLUSH;
|
|
flush->bi_bdev = bio->bi_bdev;
|
|
flush->bi_end_io = request_endio;
|
|
flush->bi_private = cl;
|
|
|
|
closure_bio_submit(flush, cl, s->d);
|
|
}
|
|
} else {
|
|
s->iop.bio = bio_clone_bioset(bio, GFP_NOIO,
|
|
dc->disk.bio_split);
|
|
|
|
closure_bio_submit(bio, cl, s->d);
|
|
}
|
|
|
|
closure_call(&s->iop.cl, bch_data_insert, NULL, cl);
|
|
continue_at(cl, cached_dev_write_complete, NULL);
|
|
}
|
|
|
|
static void cached_dev_nodata(struct closure *cl)
|
|
{
|
|
struct search *s = container_of(cl, struct search, cl);
|
|
struct bio *bio = &s->bio.bio;
|
|
|
|
if (s->iop.flush_journal)
|
|
bch_journal_meta(s->iop.c, cl);
|
|
|
|
/* If it's a flush, we send the flush to the backing device too */
|
|
closure_bio_submit(bio, cl, s->d);
|
|
|
|
continue_at(cl, cached_dev_bio_complete, NULL);
|
|
}
|
|
|
|
/* Cached devices - read & write stuff */
|
|
|
|
static void cached_dev_make_request(struct request_queue *q, struct bio *bio)
|
|
{
|
|
struct search *s;
|
|
struct bcache_device *d = bio->bi_bdev->bd_disk->private_data;
|
|
struct cached_dev *dc = container_of(d, struct cached_dev, disk);
|
|
int cpu, rw = bio_data_dir(bio);
|
|
|
|
cpu = part_stat_lock();
|
|
part_stat_inc(cpu, &d->disk->part0, ios[rw]);
|
|
part_stat_add(cpu, &d->disk->part0, sectors[rw], bio_sectors(bio));
|
|
part_stat_unlock();
|
|
|
|
bio->bi_bdev = dc->bdev;
|
|
bio->bi_sector += dc->sb.data_offset;
|
|
|
|
if (cached_dev_get(dc)) {
|
|
s = search_alloc(bio, d);
|
|
trace_bcache_request_start(s->d, bio);
|
|
|
|
if (!bio->bi_size) {
|
|
/*
|
|
* can't call bch_journal_meta from under
|
|
* generic_make_request
|
|
*/
|
|
continue_at_nobarrier(&s->cl,
|
|
cached_dev_nodata,
|
|
bcache_wq);
|
|
} else {
|
|
s->iop.bypass = check_should_bypass(dc, bio);
|
|
|
|
if (rw)
|
|
cached_dev_write(dc, s);
|
|
else
|
|
cached_dev_read(dc, s);
|
|
}
|
|
} else {
|
|
if ((bio->bi_rw & REQ_DISCARD) &&
|
|
!blk_queue_discard(bdev_get_queue(dc->bdev)))
|
|
bio_endio(bio, 0);
|
|
else
|
|
bch_generic_make_request(bio, &d->bio_split_hook);
|
|
}
|
|
}
|
|
|
|
static int cached_dev_ioctl(struct bcache_device *d, fmode_t mode,
|
|
unsigned int cmd, unsigned long arg)
|
|
{
|
|
struct cached_dev *dc = container_of(d, struct cached_dev, disk);
|
|
return __blkdev_driver_ioctl(dc->bdev, mode, cmd, arg);
|
|
}
|
|
|
|
static int cached_dev_congested(void *data, int bits)
|
|
{
|
|
struct bcache_device *d = data;
|
|
struct cached_dev *dc = container_of(d, struct cached_dev, disk);
|
|
struct request_queue *q = bdev_get_queue(dc->bdev);
|
|
int ret = 0;
|
|
|
|
if (bdi_congested(&q->backing_dev_info, bits))
|
|
return 1;
|
|
|
|
if (cached_dev_get(dc)) {
|
|
unsigned i;
|
|
struct cache *ca;
|
|
|
|
for_each_cache(ca, d->c, i) {
|
|
q = bdev_get_queue(ca->bdev);
|
|
ret |= bdi_congested(&q->backing_dev_info, bits);
|
|
}
|
|
|
|
cached_dev_put(dc);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
void bch_cached_dev_request_init(struct cached_dev *dc)
|
|
{
|
|
struct gendisk *g = dc->disk.disk;
|
|
|
|
g->queue->make_request_fn = cached_dev_make_request;
|
|
g->queue->backing_dev_info.congested_fn = cached_dev_congested;
|
|
dc->disk.cache_miss = cached_dev_cache_miss;
|
|
dc->disk.ioctl = cached_dev_ioctl;
|
|
}
|
|
|
|
/* Flash backed devices */
|
|
|
|
static int flash_dev_cache_miss(struct btree *b, struct search *s,
|
|
struct bio *bio, unsigned sectors)
|
|
{
|
|
struct bio_vec *bv;
|
|
int i;
|
|
|
|
/* Zero fill bio */
|
|
|
|
bio_for_each_segment(bv, bio, i) {
|
|
unsigned j = min(bv->bv_len >> 9, sectors);
|
|
|
|
void *p = kmap(bv->bv_page);
|
|
memset(p + bv->bv_offset, 0, j << 9);
|
|
kunmap(bv->bv_page);
|
|
|
|
sectors -= j;
|
|
}
|
|
|
|
bio_advance(bio, min(sectors << 9, bio->bi_size));
|
|
|
|
if (!bio->bi_size)
|
|
return MAP_DONE;
|
|
|
|
return MAP_CONTINUE;
|
|
}
|
|
|
|
static void flash_dev_nodata(struct closure *cl)
|
|
{
|
|
struct search *s = container_of(cl, struct search, cl);
|
|
|
|
if (s->iop.flush_journal)
|
|
bch_journal_meta(s->iop.c, cl);
|
|
|
|
continue_at(cl, search_free, NULL);
|
|
}
|
|
|
|
static void flash_dev_make_request(struct request_queue *q, struct bio *bio)
|
|
{
|
|
struct search *s;
|
|
struct closure *cl;
|
|
struct bcache_device *d = bio->bi_bdev->bd_disk->private_data;
|
|
int cpu, rw = bio_data_dir(bio);
|
|
|
|
cpu = part_stat_lock();
|
|
part_stat_inc(cpu, &d->disk->part0, ios[rw]);
|
|
part_stat_add(cpu, &d->disk->part0, sectors[rw], bio_sectors(bio));
|
|
part_stat_unlock();
|
|
|
|
s = search_alloc(bio, d);
|
|
cl = &s->cl;
|
|
bio = &s->bio.bio;
|
|
|
|
trace_bcache_request_start(s->d, bio);
|
|
|
|
if (!bio->bi_size) {
|
|
/*
|
|
* can't call bch_journal_meta from under
|
|
* generic_make_request
|
|
*/
|
|
continue_at_nobarrier(&s->cl,
|
|
flash_dev_nodata,
|
|
bcache_wq);
|
|
} else if (rw) {
|
|
bch_keybuf_check_overlapping(&s->iop.c->moving_gc_keys,
|
|
&KEY(d->id, bio->bi_sector, 0),
|
|
&KEY(d->id, bio_end_sector(bio), 0));
|
|
|
|
s->iop.bypass = (bio->bi_rw & REQ_DISCARD) != 0;
|
|
s->iop.writeback = true;
|
|
s->iop.bio = bio;
|
|
|
|
closure_call(&s->iop.cl, bch_data_insert, NULL, cl);
|
|
} else {
|
|
closure_call(&s->iop.cl, cache_lookup, NULL, cl);
|
|
}
|
|
|
|
continue_at(cl, search_free, NULL);
|
|
}
|
|
|
|
static int flash_dev_ioctl(struct bcache_device *d, fmode_t mode,
|
|
unsigned int cmd, unsigned long arg)
|
|
{
|
|
return -ENOTTY;
|
|
}
|
|
|
|
static int flash_dev_congested(void *data, int bits)
|
|
{
|
|
struct bcache_device *d = data;
|
|
struct request_queue *q;
|
|
struct cache *ca;
|
|
unsigned i;
|
|
int ret = 0;
|
|
|
|
for_each_cache(ca, d->c, i) {
|
|
q = bdev_get_queue(ca->bdev);
|
|
ret |= bdi_congested(&q->backing_dev_info, bits);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
void bch_flash_dev_request_init(struct bcache_device *d)
|
|
{
|
|
struct gendisk *g = d->disk;
|
|
|
|
g->queue->make_request_fn = flash_dev_make_request;
|
|
g->queue->backing_dev_info.congested_fn = flash_dev_congested;
|
|
d->cache_miss = flash_dev_cache_miss;
|
|
d->ioctl = flash_dev_ioctl;
|
|
}
|
|
|
|
void bch_request_exit(void)
|
|
{
|
|
#ifdef CONFIG_CGROUP_BCACHE
|
|
cgroup_unload_subsys(&bcache_subsys);
|
|
#endif
|
|
if (bch_search_cache)
|
|
kmem_cache_destroy(bch_search_cache);
|
|
}
|
|
|
|
int __init bch_request_init(void)
|
|
{
|
|
bch_search_cache = KMEM_CACHE(search, 0);
|
|
if (!bch_search_cache)
|
|
return -ENOMEM;
|
|
|
|
#ifdef CONFIG_CGROUP_BCACHE
|
|
cgroup_load_subsys(&bcache_subsys);
|
|
init_bch_cgroup(&bcache_default_cgroup);
|
|
|
|
cgroup_add_cftypes(&bcache_subsys, bch_files);
|
|
#endif
|
|
return 0;
|
|
}
|