1346 lines
34 KiB
C
1346 lines
34 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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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/module.h>
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#include <linux/hash.h>
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#include <linux/random.h>
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#include <linux/backing-dev.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 *cl);
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static unsigned int cache_mode(struct cached_dev *dc)
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{
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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)
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{
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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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struct bvec_iter iter;
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uint64_t csum = 0;
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bio_for_each_segment(bv, bio, iter) {
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void *d = bvec_kmap_local(&bv);
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csum = crc64_be(csum, d, bv.bv_len);
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kunmap_local(d);
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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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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->status = BLK_STS_RESOURCE;
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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, op->wq);
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return;
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}
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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 int bch_keylist_realloc(struct keylist *l, unsigned int u64s,
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struct cache_set *c)
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{
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size_t oldsize = bch_keylist_nkeys(l);
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size_t newsize = oldsize + u64s;
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/*
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* The journalling code doesn't handle the case where the keys to insert
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* is bigger than an empty write: If we just return -ENOMEM here,
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* bch_data_insert_keys() will insert the keys created so far
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* and finish the rest when the keylist is empty.
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*/
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if (newsize * sizeof(uint64_t) > block_bytes(c->cache) - sizeof(struct jset))
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return -ENOMEM;
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return __bch_keylist_realloc(l, u64s);
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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\n",
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bio_sectors(bio), (uint64_t) bio->bi_iter.bi_sector);
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while (bio_sectors(bio)) {
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unsigned int 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, 2, op->c))
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goto out;
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bio->bi_iter.bi_sector += sectors;
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bio->bi_iter.bi_size -= sectors << 9;
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bch_keylist_add(&op->insert_keys,
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&KEY(op->inode,
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bio->bi_iter.bi_sector,
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sectors));
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}
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op->insert_data_done = true;
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/* get in bch_data_insert() */
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bio_put(bio);
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out:
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continue_at(cl, bch_data_insert_keys, op->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 successfully 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)
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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 (bio->bi_status) {
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/* TODO: We could try to recover from this. */
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if (op->writeback)
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op->status = bio->bi_status;
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else if (!op->replace)
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set_closure_fn(cl, bch_data_insert_error, op->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, bio->bi_status, "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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wake_up_gc(op->c);
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/*
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* Journal writes are marked REQ_PREFLUSH; 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_opf &= ~(REQ_PREFLUSH|REQ_FUA);
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do {
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unsigned int 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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3 + (op->csum ? 1 : 0),
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op->c)) {
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continue_at(cl, bch_data_insert_keys, op->wq);
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return;
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}
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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_iter.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 = bio_next_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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bio_set_op_attrs(n, REQ_OP_WRITE, 0);
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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, op->wq);
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return;
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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, op->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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* @cl: closure pointer.
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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 op->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 op->bypass is true, instead of inserting the data it invalidates the
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* region of the cache represented by op->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->c, op->inode, op->bio,
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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? Return 0 (not congested) or the limit (in sectors)
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* beyond which we should bypass the cache due to congestion.
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*/
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unsigned int bch_get_congested(const struct cache_set *c)
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{
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int i;
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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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i -= hweight32(get_random_u32());
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return i > 0 ? i : 1;
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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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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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static bool check_should_bypass(struct cached_dev *dc, struct bio *bio)
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{
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struct cache_set *c = dc->disk.c;
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unsigned int mode = cache_mode(dc);
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unsigned int sectors, congested;
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struct task_struct *task = current;
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struct io *i;
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if (test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) ||
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c->gc_stats.in_use > CUTOFF_CACHE_ADD ||
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(bio_op(bio) == REQ_OP_DISCARD))
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goto skip;
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if (mode == CACHE_MODE_NONE ||
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(mode == CACHE_MODE_WRITEAROUND &&
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op_is_write(bio_op(bio))))
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goto skip;
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/*
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* If the bio is for read-ahead or background IO, bypass it or
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* not depends on the following situations,
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* - If the IO is for meta data, always cache it and no bypass
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* - If the IO is not meta data, check dc->cache_reada_policy,
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* BCH_CACHE_READA_ALL: cache it and not bypass
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* BCH_CACHE_READA_META_ONLY: not cache it and bypass
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* That is, read-ahead request for metadata always get cached
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* (eg, for gfs2 or xfs).
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*/
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if ((bio->bi_opf & (REQ_RAHEAD|REQ_BACKGROUND))) {
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if (!(bio->bi_opf & (REQ_META|REQ_PRIO)) &&
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(dc->cache_readahead_policy != BCH_CACHE_READA_ALL))
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goto skip;
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}
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if (bio->bi_iter.bi_sector & (c->cache->sb.block_size - 1) ||
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bio_sectors(bio) & (c->cache->sb.block_size - 1)) {
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pr_debug("skipping unaligned io\n");
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goto skip;
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}
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if (bypass_torture_test(dc)) {
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if ((get_random_int() & 3) == 3)
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goto skip;
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else
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goto rescale;
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}
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congested = bch_get_congested(c);
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if (!congested && !dc->sequential_cutoff)
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goto rescale;
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spin_lock(&dc->io_lock);
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hlist_for_each_entry(i, iohash(dc, bio->bi_iter.bi_sector), hash)
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if (i->last == bio->bi_iter.bi_sector &&
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time_before(jiffies, i->jiffies))
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goto found;
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i = list_first_entry(&dc->io_lru, struct io, lru);
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add_sequential(task);
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i->sequential = 0;
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found:
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if (i->sequential + bio->bi_iter.bi_size > i->sequential)
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i->sequential += bio->bi_iter.bi_size;
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i->last = bio_end_sector(bio);
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i->jiffies = jiffies + msecs_to_jiffies(5000);
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task->sequential_io = i->sequential;
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hlist_del(&i->hash);
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hlist_add_head(&i->hash, iohash(dc, i->last));
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list_move_tail(&i->lru, &dc->io_lru);
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spin_unlock(&dc->io_lock);
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sectors = max(task->sequential_io,
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task->sequential_io_avg) >> 9;
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|
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if (dc->sequential_cutoff &&
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sectors >= dc->sequential_cutoff >> 9) {
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trace_bcache_bypass_sequential(bio);
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goto skip;
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}
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|
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if (congested && sectors >= congested) {
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trace_bcache_bypass_congested(bio);
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goto skip;
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}
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rescale:
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bch_rescale_priorities(c, bio_sectors(bio));
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return false;
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skip:
|
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bch_mark_sectors_bypassed(c, dc, bio_sectors(bio));
|
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return true;
|
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}
|
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|
|
/* Cache lookup */
|
|
|
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struct search {
|
|
/* Stack frame for bio_complete */
|
|
struct closure cl;
|
|
|
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struct bbio bio;
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struct bio *orig_bio;
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struct bio *cache_miss;
|
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struct bcache_device *d;
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|
|
|
unsigned int insert_bio_sectors;
|
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unsigned int recoverable:1;
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|
unsigned int write:1;
|
|
unsigned int read_dirty_data:1;
|
|
unsigned int cache_missed:1;
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|
|
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struct block_device *orig_bdev;
|
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unsigned long start_time;
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|
|
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struct btree_op op;
|
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struct data_insert_op iop;
|
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};
|
|
|
|
static void bch_cache_read_endio(struct bio *bio)
|
|
{
|
|
struct bbio *b = container_of(bio, struct bbio, bio);
|
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struct closure *cl = bio->bi_private;
|
|
struct search *s = container_of(cl, struct search, cl);
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|
|
/*
|
|
* 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 void cache_lookup(struct closure *cl)
|
|
{
|
|
struct search *s = container_of(cl, 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 void search_free(struct closure *cl)
|
|
{
|
|
struct search *s = container_of(cl, 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 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);
|
|
|
|
cached_dev_put(dc);
|
|
search_free(cl);
|
|
}
|
|
|
|
/* Process reads */
|
|
|
|
static void cached_dev_read_error_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)
|
|
bio_free_pages(s->iop.bio);
|
|
|
|
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;
|
|
|
|
/*
|
|
* 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 void cached_dev_cache_miss_done(struct closure *cl)
|
|
{
|
|
struct search *s = container_of(cl, 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);
|
|
closure_put(&d->cl);
|
|
}
|
|
|
|
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->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 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_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 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_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 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 */
|
|
bio->bi_end_io = backing_request_endio;
|
|
closure_bio_submit(s->iop.c, bio, cl);
|
|
|
|
continue_at(cl, cached_dev_bio_complete, NULL);
|
|
}
|
|
|
|
struct detached_dev_io_private {
|
|
struct bcache_device *d;
|
|
unsigned long start_time;
|
|
bio_end_io_t *bi_end_io;
|
|
void *bi_private;
|
|
struct block_device *orig_bdev;
|
|
};
|
|
|
|
static void detached_dev_end_io(struct bio *bio)
|
|
{
|
|
struct detached_dev_io_private *ddip;
|
|
|
|
ddip = bio->bi_private;
|
|
bio->bi_end_io = ddip->bi_end_io;
|
|
bio->bi_private = ddip->bi_private;
|
|
|
|
/* Count on the bcache device */
|
|
bio_end_io_acct_remapped(bio, ddip->start_time, ddip->orig_bdev);
|
|
|
|
if (bio->bi_status) {
|
|
struct cached_dev *dc = container_of(ddip->d,
|
|
struct cached_dev, disk);
|
|
/* should count I/O error for backing device here */
|
|
bch_count_backing_io_errors(dc, bio);
|
|
}
|
|
|
|
kfree(ddip);
|
|
bio->bi_end_io(bio);
|
|
}
|
|
|
|
static void detached_dev_do_request(struct bcache_device *d, struct bio *bio,
|
|
struct block_device *orig_bdev, unsigned long start_time)
|
|
{
|
|
struct detached_dev_io_private *ddip;
|
|
struct cached_dev *dc = container_of(d, struct cached_dev, disk);
|
|
|
|
/*
|
|
* no need to call closure_get(&dc->disk.cl),
|
|
* because upper layer had already opened bcache device,
|
|
* which would call closure_get(&dc->disk.cl)
|
|
*/
|
|
ddip = kzalloc(sizeof(struct detached_dev_io_private), GFP_NOIO);
|
|
if (!ddip) {
|
|
bio->bi_status = BLK_STS_RESOURCE;
|
|
bio->bi_end_io(bio);
|
|
return;
|
|
}
|
|
|
|
ddip->d = d;
|
|
/* Count on the bcache device */
|
|
ddip->orig_bdev = orig_bdev;
|
|
ddip->start_time = start_time;
|
|
ddip->bi_end_io = bio->bi_end_io;
|
|
ddip->bi_private = bio->bi_private;
|
|
bio->bi_end_io = detached_dev_end_io;
|
|
bio->bi_private = ddip;
|
|
|
|
if ((bio_op(bio) == REQ_OP_DISCARD) &&
|
|
!bdev_max_discard_sectors(dc->bdev))
|
|
bio->bi_end_io(bio);
|
|
else
|
|
submit_bio_noacct(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_set_dev(bio, dc->bdev);
|
|
bio->bi_iter.bi_sector += dc->sb.data_offset;
|
|
|
|
if (cached_dev_get(dc)) {
|
|
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, orig_bdev, start_time);
|
|
}
|
|
|
|
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);
|
|
|
|
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 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);
|
|
}
|
|
|
|
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, fmode_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;
|
|
}
|