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-rw-r--r--drivers/md/bcache/request.c1345
1 files changed, 1345 insertions, 0 deletions
diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c
new file mode 100644
index 000000000..a9b1f3896
--- /dev/null
+++ b/drivers/md/bcache/request.c
@@ -0,0 +1,1345 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Main bcache entry point - handle a read or a write request and decide what to
+ * do with it; the make_request functions are called by the block layer.
+ *
+ * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
+ * Copyright 2012 Google, Inc.
+ */
+
+#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 void bch_data_insert_start(struct closure *cl);
+
+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 void bch_data_insert_keys(struct closure *cl)
+{
+ struct data_insert_op *op = container_of(cl, 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 void bch_data_insert_error(struct closure *cl)
+{
+ struct data_insert_op *op = container_of(cl, 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);
+}
+
+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 void bch_data_insert_start(struct closure *cl)
+{
+ struct data_insert_op *op = container_of(cl, 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.
+ */
+void bch_data_insert(struct closure *cl)
+{
+ struct data_insert_op *op = container_of(cl, 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);
+}
+
+/*
+ * 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) ||
+ c->gc_stats.in_use > CUTOFF_CACHE_ADD ||
+ (bio_op(bio) == REQ_OP_DISCARD))
+ 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 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, 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 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, 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;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-14 09:47:14 +0000