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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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#include "bcache.h"#include "btree.h"#include "debug.h"#include "request.h"#include "writeback.h"
#include <linux/module.h>#include <linux/hash.h>#include <linux/random.h>#include <linux/backing-dev.h>
#include <trace/events/bcache.h>
#define CUTOFF_CACHE_ADD 95#define CUTOFF_CACHE_READA 90
struct kmem_cache *bch_search_cache;
static CLOSURE_CALLBACK(bch_data_insert_start);
static unsigned int cache_mode(struct cached_dev *dc){ return BDEV_CACHE_MODE(&dc->sb);}
static bool verify(struct cached_dev *dc){ return dc->verify;}
static void bio_csum(struct bio *bio, struct bkey *k){ struct bio_vec bv; struct bvec_iter iter; uint64_t csum = 0;
bio_for_each_segment(bv, bio, iter) { void *d = bvec_kmap_local(&bv);
csum = crc64_be(csum, d, bv.bv_len); kunmap_local(d); }
k->ptr[KEY_PTRS(k)] = csum & (~0ULL >> 1);}
/* Insert data into cache */
static CLOSURE_CALLBACK(bch_data_insert_keys){ closure_type(op, struct data_insert_op, cl); atomic_t *journal_ref = NULL; struct bkey *replace_key = op->replace ? &op->replace_key : NULL; int ret;
if (!op->replace) journal_ref = bch_journal(op->c, &op->insert_keys, op->flush_journal ? cl : NULL);
ret = bch_btree_insert(op->c, &op->insert_keys, journal_ref, replace_key); if (ret == -ESRCH) { op->replace_collision = true; } else if (ret) { op->status = BLK_STS_RESOURCE; op->insert_data_done = true; }
if (journal_ref) atomic_dec_bug(journal_ref);
if (!op->insert_data_done) { continue_at(cl, bch_data_insert_start, op->wq); return; }
bch_keylist_free(&op->insert_keys); closure_return(cl);}
static int bch_keylist_realloc(struct keylist *l, unsigned int u64s, struct cache_set *c){ size_t oldsize = bch_keylist_nkeys(l); size_t newsize = oldsize + u64s;
/* * The journalling code doesn't handle the case where the keys to insert * is bigger than an empty write: If we just return -ENOMEM here, * bch_data_insert_keys() will insert the keys created so far * and finish the rest when the keylist is empty. */ if (newsize * sizeof(uint64_t) > block_bytes(c->cache) - sizeof(struct jset)) return -ENOMEM;
return __bch_keylist_realloc(l, u64s);}
static void bch_data_invalidate(struct closure *cl){ struct data_insert_op *op = container_of(cl, struct data_insert_op, cl); struct bio *bio = op->bio;
pr_debug("invalidating %i sectors from %llu\n", bio_sectors(bio), (uint64_t) bio->bi_iter.bi_sector);
while (bio_sectors(bio)) { unsigned int sectors = min(bio_sectors(bio), 1U << (KEY_SIZE_BITS - 1));
if (bch_keylist_realloc(&op->insert_keys, 2, op->c)) goto out;
bio->bi_iter.bi_sector += sectors; bio->bi_iter.bi_size -= sectors << 9;
bch_keylist_add(&op->insert_keys, &KEY(op->inode, bio->bi_iter.bi_sector, sectors)); }
op->insert_data_done = true; /* get in bch_data_insert() */ bio_put(bio);out: continue_at(cl, bch_data_insert_keys, op->wq);}
static CLOSURE_CALLBACK(bch_data_insert_error){ closure_type(op, struct data_insert_op, cl);
/* * Our data write just errored, which means we've got a bunch of keys to * insert that point to data that wasn't successfully written. * * We don't have to insert those keys but we still have to invalidate * that region of the cache - so, if we just strip off all the pointers * from the keys we'll accomplish just that. */
struct bkey *src = op->insert_keys.keys, *dst = op->insert_keys.keys;
while (src != op->insert_keys.top) { struct bkey *n = bkey_next(src);
SET_KEY_PTRS(src, 0); memmove(dst, src, bkey_bytes(src));
dst = bkey_next(dst); src = n; }
op->insert_keys.top = dst;
bch_data_insert_keys(&cl->work);}
static void bch_data_insert_endio(struct bio *bio){ struct closure *cl = bio->bi_private; struct data_insert_op *op = container_of(cl, struct data_insert_op, cl);
if (bio->bi_status) { /* TODO: We could try to recover from this. */ if (op->writeback) op->status = bio->bi_status; else if (!op->replace) set_closure_fn(cl, bch_data_insert_error, op->wq); else set_closure_fn(cl, NULL, NULL); }
bch_bbio_endio(op->c, bio, bio->bi_status, "writing data to cache");}
static CLOSURE_CALLBACK(bch_data_insert_start){ closure_type(op, struct data_insert_op, cl); struct bio *bio = op->bio, *n;
if (op->bypass) return bch_data_invalidate(cl);
if (atomic_sub_return(bio_sectors(bio), &op->c->sectors_to_gc) < 0) wake_up_gc(op->c);
/* * Journal writes are marked REQ_PREFLUSH; if the original write was a * flush, it'll wait on the journal write. */ bio->bi_opf &= ~(REQ_PREFLUSH|REQ_FUA);
do { unsigned int i; struct bkey *k; struct bio_set *split = &op->c->bio_split;
/* 1 for the device pointer and 1 for the chksum */ if (bch_keylist_realloc(&op->insert_keys, 3 + (op->csum ? 1 : 0), op->c)) { continue_at(cl, bch_data_insert_keys, op->wq); return; }
k = op->insert_keys.top; bkey_init(k); SET_KEY_INODE(k, op->inode); SET_KEY_OFFSET(k, bio->bi_iter.bi_sector);
if (!bch_alloc_sectors(op->c, k, bio_sectors(bio), op->write_point, op->write_prio, op->writeback)) goto err;
n = bio_next_split(bio, KEY_SIZE(k), GFP_NOIO, split);
n->bi_end_io = bch_data_insert_endio; n->bi_private = cl;
if (op->writeback) { SET_KEY_DIRTY(k, true);
for (i = 0; i < KEY_PTRS(k); i++) SET_GC_MARK(PTR_BUCKET(op->c, k, i), GC_MARK_DIRTY); }
SET_KEY_CSUM(k, op->csum); if (KEY_CSUM(k)) bio_csum(n, k);
trace_bcache_cache_insert(k); bch_keylist_push(&op->insert_keys);
n->bi_opf = REQ_OP_WRITE; bch_submit_bbio(n, op->c, k, 0); } while (n != bio);
op->insert_data_done = true; continue_at(cl, bch_data_insert_keys, op->wq); return;err: /* bch_alloc_sectors() blocks if s->writeback = true */ BUG_ON(op->writeback);
/* * But if it's not a writeback write we'd rather just bail out if * there aren't any buckets ready to write to - it might take awhile and * we might be starving btree writes for gc or something. */
if (!op->replace) { /* * Writethrough write: We can't complete the write until we've * updated the index. But we don't want to delay the write while * we wait for buckets to be freed up, so just invalidate the * rest of the write. */ op->bypass = true; return bch_data_invalidate(cl); } else { /* * From a cache miss, we can just insert the keys for the data * we have written or bail out if we didn't do anything. */ op->insert_data_done = true; bio_put(bio);
if (!bch_keylist_empty(&op->insert_keys)) continue_at(cl, bch_data_insert_keys, op->wq); else closure_return(cl); }}
/** * bch_data_insert - stick some data in the cache * @cl: closure pointer. * * This is the starting point for any data to end up in a cache device; it could * be from a normal write, or a writeback write, or a write to a flash only * volume - it's also used by the moving garbage collector to compact data in * mostly empty buckets. * * It first writes the data to the cache, creating a list of keys to be inserted * (if the data had to be fragmented there will be multiple keys); after the * data is written it calls bch_journal, and after the keys have been added to * the next journal write they're inserted into the btree. * * It inserts the data in op->bio; bi_sector is used for the key offset, * and op->inode is used for the key inode. * * If op->bypass is true, instead of inserting the data it invalidates the * region of the cache represented by op->bio and op->inode. */CLOSURE_CALLBACK(bch_data_insert){ closure_type(op, struct data_insert_op, cl);
trace_bcache_write(op->c, op->inode, op->bio, op->writeback, op->bypass);
bch_keylist_init(&op->insert_keys); bio_get(op->bio); bch_data_insert_start(&cl->work);}
/* * Congested? Return 0 (not congested) or the limit (in sectors) * beyond which we should bypass the cache due to congestion. */unsigned int bch_get_congested(const struct cache_set *c){ int i;
if (!c->congested_read_threshold_us && !c->congested_write_threshold_us) return 0;
i = (local_clock_us() - c->congested_last_us) / 1024; if (i < 0) return 0;
i += atomic_read(&c->congested); if (i >= 0) return 0;
i += CONGESTED_MAX;
if (i > 0) i = fract_exp_two(i, 6);
i -= hweight32(get_random_u32());
return i > 0 ? i : 1;}
static void add_sequential(struct task_struct *t){ ewma_add(t->sequential_io_avg, t->sequential_io, 8, 0);
t->sequential_io = 0;}
static struct hlist_head *iohash(struct cached_dev *dc, uint64_t k){ return &dc->io_hash[hash_64(k, RECENT_IO_BITS)];}
static bool check_should_bypass(struct cached_dev *dc, struct bio *bio){ struct cache_set *c = dc->disk.c; unsigned int mode = cache_mode(dc); unsigned int sectors, congested; struct task_struct *task = current; struct io *i;
if (test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) || (bio_op(bio) == REQ_OP_DISCARD)) goto skip;
if (c->gc_stats.in_use > CUTOFF_CACHE_ADD) { /* * If cached buckets are all clean now, 'true' will be * returned and all requests will bypass the cache device. * Then c->sectors_to_gc has no chance to be negative, and * gc thread won't wake up and caching won't work forever. * Here call force_wake_up_gc() to avoid such aftermath. */ if (BDEV_STATE(&dc->sb) == BDEV_STATE_CLEAN && c->gc_mark_valid) force_wake_up_gc(c);
goto skip; }
if (mode == CACHE_MODE_NONE || (mode == CACHE_MODE_WRITEAROUND && op_is_write(bio_op(bio)))) goto skip;
/* * If the bio is for read-ahead or background IO, bypass it or * not depends on the following situations, * - If the IO is for meta data, always cache it and no bypass * - If the IO is not meta data, check dc->cache_reada_policy, * BCH_CACHE_READA_ALL: cache it and not bypass * BCH_CACHE_READA_META_ONLY: not cache it and bypass * That is, read-ahead request for metadata always get cached * (eg, for gfs2 or xfs). */ if ((bio->bi_opf & (REQ_RAHEAD|REQ_BACKGROUND))) { if (!(bio->bi_opf & (REQ_META|REQ_PRIO)) && (dc->cache_readahead_policy != BCH_CACHE_READA_ALL)) goto skip; }
if (bio->bi_iter.bi_sector & (c->cache->sb.block_size - 1) || bio_sectors(bio) & (c->cache->sb.block_size - 1)) { pr_debug("skipping unaligned io\n"); goto skip; }
if (bypass_torture_test(dc)) { if (get_random_u32_below(4) == 3) goto skip; else goto rescale; }
congested = bch_get_congested(c); if (!congested && !dc->sequential_cutoff) goto rescale;
spin_lock(&dc->io_lock);
hlist_for_each_entry(i, iohash(dc, bio->bi_iter.bi_sector), hash) if (i->last == bio->bi_iter.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_iter.bi_size > i->sequential) i->sequential += bio->bi_iter.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 bbio bio; struct bio *orig_bio; struct bio *cache_miss; struct bcache_device *d;
unsigned int insert_bio_sectors; unsigned int recoverable:1; unsigned int write:1; unsigned int read_dirty_data:1; unsigned int cache_missed:1;
struct block_device *orig_bdev; unsigned long start_time;
struct btree_op op; struct data_insert_op iop;};
static void bch_cache_read_endio(struct bio *bio){ 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 (bio->bi_status) s->iop.status = bio->bi_status; else if (!KEY_DIRTY(&b->key) && ptr_stale(s->iop.c, &b->key, 0)) { atomic_long_inc(&s->iop.c->cache_read_races); s->iop.status = BLK_STS_IOERR; }
bch_bbio_endio(s->iop.c, bio, bio->bi_status, "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 int ptr;
if (bkey_cmp(k, &KEY(s->iop.inode, bio->bi_iter.bi_sector, 0)) <= 0) return MAP_CONTINUE;
if (KEY_INODE(k) != s->iop.inode || KEY_START(k) > bio->bi_iter.bi_sector) { unsigned int bio_sectors = bio_sectors(bio); unsigned int sectors = KEY_INODE(k) == s->iop.inode ? min_t(uint64_t, INT_MAX, KEY_START(k) - bio->bi_iter.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 = bio_next_split(bio, min_t(uint64_t, INT_MAX, KEY_OFFSET(k) - bio->bi_iter.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_iter.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 CLOSURE_CALLBACK(cache_lookup){ closure_type(s, struct search, iop.cl); struct bio *bio = &s->bio.bio; struct cached_dev *dc; int ret;
bch_btree_op_init(&s->op, -1);
ret = bch_btree_map_keys(&s->op, s->iop.c, &KEY(s->iop.inode, bio->bi_iter.bi_sector, 0), cache_lookup_fn, MAP_END_KEY); if (ret == -EAGAIN) { continue_at(cl, cache_lookup, bcache_wq); return; }
/* * We might meet err when searching the btree, If that happens, we will * get negative ret, in this scenario we should not recover data from * backing device (when cache device is dirty) because we don't know * whether bkeys the read request covered are all clean. * * And after that happened, s->iop.status is still its initial value * before we submit s->bio.bio */ if (ret < 0) { BUG_ON(ret == -EINTR); if (s->d && s->d->c && !UUID_FLASH_ONLY(&s->d->c->uuids[s->d->id])) { dc = container_of(s->d, struct cached_dev, disk); if (dc && atomic_read(&dc->has_dirty)) s->recoverable = false; } if (!s->iop.status) s->iop.status = BLK_STS_IOERR; }
closure_return(cl);}
/* Common code for the make_request functions */
static void request_endio(struct bio *bio){ struct closure *cl = bio->bi_private;
if (bio->bi_status) { struct search *s = container_of(cl, struct search, cl);
s->iop.status = bio->bi_status; /* Only cache read errors are recoverable */ s->recoverable = false; }
bio_put(bio); closure_put(cl);}
static void backing_request_endio(struct bio *bio){ struct closure *cl = bio->bi_private;
if (bio->bi_status) { struct search *s = container_of(cl, struct search, cl); struct cached_dev *dc = container_of(s->d, struct cached_dev, disk); /* * If a bio has REQ_PREFLUSH for writeback mode, it is * speically assembled in cached_dev_write() for a non-zero * write request which has REQ_PREFLUSH. we don't set * s->iop.status by this failure, the status will be decided * by result of bch_data_insert() operation. */ if (unlikely(s->iop.writeback && bio->bi_opf & REQ_PREFLUSH)) { pr_err("Can't flush %pg: returned bi_status %i\n", dc->bdev, bio->bi_status); } else { /* set to orig_bio->bi_status in bio_complete() */ s->iop.status = bio->bi_status; } s->recoverable = false; /* should count I/O error for backing device here */ bch_count_backing_io_errors(dc, bio); }
bio_put(bio); closure_put(cl);}
static void bio_complete(struct search *s){ if (s->orig_bio) { /* Count on bcache device */ bio_end_io_acct_remapped(s->orig_bio, s->start_time, s->orig_bdev); trace_bcache_request_end(s->d, s->orig_bio); s->orig_bio->bi_status = s->iop.status; bio_endio(s->orig_bio); s->orig_bio = NULL; }}
static void do_bio_hook(struct search *s, struct bio *orig_bio, bio_end_io_t *end_io_fn){ struct bio *bio = &s->bio.bio;
bio_init_clone(orig_bio->bi_bdev, bio, orig_bio, GFP_NOIO); /* * bi_end_io can be set separately somewhere else, e.g. the * variants in, * - cache_bio->bi_end_io from cached_dev_cache_miss() * - n->bi_end_io from cache_lookup_fn() */ bio->bi_end_io = end_io_fn; bio->bi_private = &s->cl;
bio_cnt_set(bio, 3);}
static CLOSURE_CALLBACK(search_free){ closure_type(s, struct search, cl);
atomic_dec(&s->iop.c->search_inflight);
if (s->iop.bio) bio_put(s->iop.bio);
bio_complete(s); closure_debug_destroy(cl); mempool_free(s, &s->iop.c->search);}
static inline struct search *search_alloc(struct bio *bio, struct bcache_device *d, struct block_device *orig_bdev, unsigned long start_time){ struct search *s;
s = mempool_alloc(&d->c->search, GFP_NOIO);
closure_init(&s->cl, NULL); do_bio_hook(s, bio, request_endio); atomic_inc(&d->c->search_inflight);
s->orig_bio = bio; s->cache_miss = NULL; s->cache_missed = 0; s->d = d; s->recoverable = 1; s->write = op_is_write(bio_op(bio)); s->read_dirty_data = 0; /* Count on the bcache device */ s->orig_bdev = orig_bdev; s->start_time = start_time; s->iop.c = d->c; s->iop.bio = NULL; s->iop.inode = d->id; s->iop.write_point = hash_long((unsigned long) current, 16); s->iop.write_prio = 0; s->iop.status = 0; s->iop.flags = 0; s->iop.flush_journal = op_is_flush(bio->bi_opf); s->iop.wq = bcache_wq;
return s;}
/* Cached devices */
static CLOSURE_CALLBACK(cached_dev_bio_complete){ closure_type(s, struct search, cl); struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
cached_dev_put(dc); search_free(&cl->work);}
/* Process reads */
static CLOSURE_CALLBACK(cached_dev_read_error_done){ closure_type(s, struct search, cl);
if (s->iop.replace_collision) bch_mark_cache_miss_collision(s->iop.c, s->d);
if (s->iop.bio) bio_free_pages(s->iop.bio);
cached_dev_bio_complete(&cl->work);}
static CLOSURE_CALLBACK(cached_dev_read_error){ closure_type(s, struct search, cl); struct bio *bio = &s->bio.bio;
/* * If read request hit dirty data (s->read_dirty_data is true), * then recovery a failed read request from cached device may * get a stale data back. So read failure recovery is only * permitted when read request hit clean data in cache device, * or when cache read race happened. */ if (s->recoverable && !s->read_dirty_data) { /* Retry from the backing device: */ trace_bcache_read_retry(s->orig_bio);
s->iop.status = 0; do_bio_hook(s, s->orig_bio, backing_request_endio);
/* XXX: invalidate cache */
/* I/O request sent to backing device */ closure_bio_submit(s->iop.c, bio, cl); }
continue_at(cl, cached_dev_read_error_done, NULL);}
static CLOSURE_CALLBACK(cached_dev_cache_miss_done){ closure_type(s, struct search, cl); struct bcache_device *d = s->d;
if (s->iop.replace_collision) bch_mark_cache_miss_collision(s->iop.c, s->d);
if (s->iop.bio) bio_free_pages(s->iop.bio);
cached_dev_bio_complete(&cl->work); closure_put(&d->cl);}
static CLOSURE_CALLBACK(cached_dev_read_done){ closure_type(s, 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->cache_miss->bi_bdev, REQ_OP_READ); s->iop.bio->bi_iter.bi_sector = s->cache_miss->bi_iter.bi_sector; s->iop.bio->bi_iter.bi_size = s->insert_bio_sectors << 9; bio_clone_blkg_association(s->iop.bio, s->cache_miss); 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->recoverable && !s->read_dirty_data) bch_data_verify(dc, s->orig_bio);
closure_get(&dc->disk.cl); 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 CLOSURE_CALLBACK(cached_dev_read_done_bh){ closure_type(s, 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_missed, s->iop.bypass); trace_bcache_read(s->orig_bio, !s->cache_missed, s->iop.bypass);
if (s->iop.status) continue_at_nobarrier(cl, cached_dev_read_error, bcache_wq); else if (s->iop.bio || verify(dc)) 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 int sectors){ int ret = MAP_CONTINUE; struct cached_dev *dc = container_of(s->d, struct cached_dev, disk); struct bio *miss, *cache_bio; unsigned int size_limit;
s->cache_missed = 1;
if (s->cache_miss || s->iop.bypass) { miss = bio_next_split(bio, sectors, GFP_NOIO, &s->d->bio_split); ret = miss == bio ? MAP_DONE : MAP_CONTINUE; goto out_submit; }
/* Limitation for valid replace key size and cache_bio bvecs number */ size_limit = min_t(unsigned int, BIO_MAX_VECS * PAGE_SECTORS, (1 << KEY_SIZE_BITS) - 1); s->insert_bio_sectors = min3(size_limit, sectors, bio_sectors(bio));
s->iop.replace_key = KEY(s->iop.inode, bio->bi_iter.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 = bio_next_split(bio, s->insert_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(miss->bi_bdev, DIV_ROUND_UP(s->insert_bio_sectors, PAGE_SECTORS), 0, GFP_NOWAIT, &dc->disk.bio_split); if (!cache_bio) goto out_submit;
cache_bio->bi_iter.bi_sector = miss->bi_iter.bi_sector; cache_bio->bi_iter.bi_size = s->insert_bio_sectors << 9;
cache_bio->bi_end_io = backing_request_endio; cache_bio->bi_private = &s->cl;
bch_bio_map(cache_bio, NULL); if (bch_bio_alloc_pages(cache_bio, __GFP_NOWARN|GFP_NOIO)) goto out_put;
s->cache_miss = miss; s->iop.bio = cache_bio; bio_get(cache_bio); /* I/O request sent to backing device */ closure_bio_submit(s->iop.c, cache_bio, &s->cl);
return ret;out_put: bio_put(cache_bio);out_submit: miss->bi_end_io = backing_request_endio; miss->bi_private = &s->cl; /* I/O request sent to backing device */ closure_bio_submit(s->iop.c, miss, &s->cl); 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 CLOSURE_CALLBACK(cached_dev_write_complete){ closure_type(s, 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->work);}
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_iter.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_op(bio) == REQ_OP_DISCARD) s->iop.bypass = true;
if (should_writeback(dc, s->orig_bio, cache_mode(dc), 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_op(bio) == REQ_OP_DISCARD && !bdev_max_discard_sectors(dc->bdev)) goto insert_data;
/* I/O request sent to backing device */ bio->bi_end_io = backing_request_endio; closure_bio_submit(s->iop.c, bio, cl);
} else if (s->iop.writeback) { bch_writeback_add(dc); s->iop.bio = bio;
if (bio->bi_opf & REQ_PREFLUSH) { /* * Also need to send a flush to the backing * device. */ struct bio *flush;
flush = bio_alloc_bioset(bio->bi_bdev, 0, REQ_OP_WRITE | REQ_PREFLUSH, GFP_NOIO, &dc->disk.bio_split); if (!flush) { s->iop.status = BLK_STS_RESOURCE; goto insert_data; } flush->bi_end_io = backing_request_endio; flush->bi_private = cl; /* I/O request sent to backing device */ closure_bio_submit(s->iop.c, flush, cl); } } else { s->iop.bio = bio_alloc_clone(bio->bi_bdev, bio, GFP_NOIO, &dc->disk.bio_split); /* I/O request sent to backing device */ bio->bi_end_io = backing_request_endio; closure_bio_submit(s->iop.c, bio, cl); }
insert_data: closure_call(&s->iop.cl, bch_data_insert, NULL, cl); continue_at(cl, cached_dev_write_complete, NULL);}
static CLOSURE_CALLBACK(cached_dev_nodata){ closure_type(s, 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 */ bio->bi_end_io = backing_request_endio; closure_bio_submit(s->iop.c, bio, cl);
continue_at(cl, cached_dev_bio_complete, NULL);}
static void detached_dev_end_io(struct bio *bio){ struct detached_dev_io_private *ddip = container_of(bio, struct detached_dev_io_private, bio); struct bio *orig_bio = ddip->orig_bio;
/* Count on the bcache device */ bio_end_io_acct(orig_bio, ddip->start_time);
if (bio->bi_status) { struct cached_dev *dc = bio->bi_private;
/* should count I/O error for backing device here */ bch_count_backing_io_errors(dc, bio); orig_bio->bi_status = bio->bi_status; }
bio_put(bio); bio_endio(orig_bio);}
static void detached_dev_do_request(struct bcache_device *d, struct bio *orig_bio, unsigned long start_time){ struct detached_dev_io_private *ddip; struct cached_dev *dc = container_of(d, struct cached_dev, disk); struct bio *clone_bio;
if (bio_op(orig_bio) == REQ_OP_DISCARD && !bdev_max_discard_sectors(dc->bdev)) { bio_end_io_acct(orig_bio, start_time); bio_endio(orig_bio); return; }
clone_bio = bio_alloc_clone(dc->bdev, orig_bio, GFP_NOIO, &d->bio_detached);
ddip = container_of(clone_bio, struct detached_dev_io_private, bio); /* Count on the bcache device */ ddip->d = d; ddip->start_time = start_time; ddip->orig_bio = orig_bio;
clone_bio->bi_end_io = detached_dev_end_io; clone_bio->bi_private = dc;
submit_bio_noacct(clone_bio);}
static void quit_max_writeback_rate(struct cache_set *c, struct cached_dev *this_dc){ int i; struct bcache_device *d; struct cached_dev *dc;
/* * mutex bch_register_lock may compete with other parallel requesters, * or attach/detach operations on other backing device. Waiting to * the mutex lock may increase I/O request latency for seconds or more. * To avoid such situation, if mutext_trylock() failed, only writeback * rate of current cached device is set to 1, and __update_write_back() * will decide writeback rate of other cached devices (remember now * c->idle_counter is 0 already). */ if (mutex_trylock(&bch_register_lock)) { for (i = 0; i < c->devices_max_used; i++) { if (!c->devices[i]) continue;
if (UUID_FLASH_ONLY(&c->uuids[i])) continue;
d = c->devices[i]; dc = container_of(d, struct cached_dev, disk); /* * set writeback rate to default minimum value, * then let update_writeback_rate() to decide the * upcoming rate. */ atomic_long_set(&dc->writeback_rate.rate, 1); } mutex_unlock(&bch_register_lock); } else atomic_long_set(&this_dc->writeback_rate.rate, 1);}
/* Cached devices - read & write stuff */
void cached_dev_submit_bio(struct bio *bio){ struct search *s; struct block_device *orig_bdev = bio->bi_bdev; struct bcache_device *d = orig_bdev->bd_disk->private_data; struct cached_dev *dc = container_of(d, struct cached_dev, disk); unsigned long start_time; int rw = bio_data_dir(bio);
if (unlikely((d->c && test_bit(CACHE_SET_IO_DISABLE, &d->c->flags)) || dc->io_disable)) { bio->bi_status = BLK_STS_IOERR; bio_endio(bio); return; }
if (likely(d->c)) { if (atomic_read(&d->c->idle_counter)) atomic_set(&d->c->idle_counter, 0); /* * If at_max_writeback_rate of cache set is true and new I/O * comes, quit max writeback rate of all cached devices * attached to this cache set, and set at_max_writeback_rate * to false. */ if (unlikely(atomic_read(&d->c->at_max_writeback_rate) == 1)) { atomic_set(&d->c->at_max_writeback_rate, 0); quit_max_writeback_rate(d->c, dc); } }
start_time = bio_start_io_acct(bio);
bio->bi_iter.bi_sector += dc->sb.data_offset;
if (cached_dev_get(dc)) { bio_set_dev(bio, dc->bdev); s = search_alloc(bio, d, orig_bdev, start_time); trace_bcache_request_start(s->d, bio);
if (!bio->bi_iter.bi_size) { /* * can't call bch_journal_meta from under * submit_bio_noacct */ 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 { /* I/O request sent to backing device */ detached_dev_do_request(d, bio, start_time); }}
static int cached_dev_ioctl(struct bcache_device *d, blk_mode_t mode, unsigned int cmd, unsigned long arg){ struct cached_dev *dc = container_of(d, struct cached_dev, disk);
if (dc->io_disable) return -EIO; if (!dc->bdev->bd_disk->fops->ioctl) return -ENOTTY; return dc->bdev->bd_disk->fops->ioctl(dc->bdev, mode, cmd, arg);}
void bch_cached_dev_request_init(struct cached_dev *dc){ 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 int sectors){ unsigned int bytes = min(sectors, bio_sectors(bio)) << 9;
swap(bio->bi_iter.bi_size, bytes); zero_fill_bio(bio); swap(bio->bi_iter.bi_size, bytes);
bio_advance(bio, bytes);
if (!bio->bi_iter.bi_size) return MAP_DONE;
return MAP_CONTINUE;}
static CLOSURE_CALLBACK(flash_dev_nodata){ closure_type(s, struct search, cl);
if (s->iop.flush_journal) bch_journal_meta(s->iop.c, cl);
continue_at(cl, search_free, NULL);}
void flash_dev_submit_bio(struct bio *bio){ struct search *s; struct closure *cl; struct bcache_device *d = bio->bi_bdev->bd_disk->private_data;
if (unlikely(d->c && test_bit(CACHE_SET_IO_DISABLE, &d->c->flags))) { bio->bi_status = BLK_STS_IOERR; bio_endio(bio); return; }
s = search_alloc(bio, d, bio->bi_bdev, bio_start_io_acct(bio)); cl = &s->cl; bio = &s->bio.bio;
trace_bcache_request_start(s->d, bio);
if (!bio->bi_iter.bi_size) { /* * can't call bch_journal_meta from under submit_bio_noacct */ continue_at_nobarrier(&s->cl, flash_dev_nodata, bcache_wq); return; } else if (bio_data_dir(bio)) { bch_keybuf_check_overlapping(&s->iop.c->moving_gc_keys, &KEY(d->id, bio->bi_iter.bi_sector, 0), &KEY(d->id, bio_end_sector(bio), 0));
s->iop.bypass = (bio_op(bio) == REQ_OP_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, blk_mode_t mode, unsigned int cmd, unsigned long arg){ return -ENOTTY;}
void bch_flash_dev_request_init(struct bcache_device *d){ d->cache_miss = flash_dev_cache_miss; d->ioctl = flash_dev_ioctl;}
void bch_request_exit(void){ 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;
return 0;}