v4.19.13 snapshot.
diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
new file mode 100644
index 0000000..3f4211b
--- /dev/null
+++ b/drivers/md/bcache/btree.c
@@ -0,0 +1,2604 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2010 Kent Overstreet <kent.overstreet@gmail.com>
+ *
+ * Uses a block device as cache for other block devices; optimized for SSDs.
+ * All allocation is done in buckets, which should match the erase block size
+ * of the device.
+ *
+ * Buckets containing cached data are kept on a heap sorted by priority;
+ * bucket priority is increased on cache hit, and periodically all the buckets
+ * on the heap have their priority scaled down. This currently is just used as
+ * an LRU but in the future should allow for more intelligent heuristics.
+ *
+ * Buckets have an 8 bit counter; freeing is accomplished by incrementing the
+ * counter. Garbage collection is used to remove stale pointers.
+ *
+ * Indexing is done via a btree; nodes are not necessarily fully sorted, rather
+ * as keys are inserted we only sort the pages that have not yet been written.
+ * When garbage collection is run, we resort the entire node.
+ *
+ * All configuration is done via sysfs; see Documentation/admin-guide/bcache.rst.
+ */
+
+#include "bcache.h"
+#include "btree.h"
+#include "debug.h"
+#include "extents.h"
+
+#include <linux/slab.h>
+#include <linux/bitops.h>
+#include <linux/hash.h>
+#include <linux/kthread.h>
+#include <linux/prefetch.h>
+#include <linux/random.h>
+#include <linux/rcupdate.h>
+#include <linux/sched/clock.h>
+#include <linux/rculist.h>
+
+#include <trace/events/bcache.h>
+
+/*
+ * Todo:
+ * register_bcache: Return errors out to userspace correctly
+ *
+ * Writeback: don't undirty key until after a cache flush
+ *
+ * Create an iterator for key pointers
+ *
+ * On btree write error, mark bucket such that it won't be freed from the cache
+ *
+ * Journalling:
+ * Check for bad keys in replay
+ * Propagate barriers
+ * Refcount journal entries in journal_replay
+ *
+ * Garbage collection:
+ * Finish incremental gc
+ * Gc should free old UUIDs, data for invalid UUIDs
+ *
+ * Provide a way to list backing device UUIDs we have data cached for, and
+ * probably how long it's been since we've seen them, and a way to invalidate
+ * dirty data for devices that will never be attached again
+ *
+ * Keep 1 min/5 min/15 min statistics of how busy a block device has been, so
+ * that based on that and how much dirty data we have we can keep writeback
+ * from being starved
+ *
+ * Add a tracepoint or somesuch to watch for writeback starvation
+ *
+ * When btree depth > 1 and splitting an interior node, we have to make sure
+ * alloc_bucket() cannot fail. This should be true but is not completely
+ * obvious.
+ *
+ * Plugging?
+ *
+ * If data write is less than hard sector size of ssd, round up offset in open
+ * bucket to the next whole sector
+ *
+ * Superblock needs to be fleshed out for multiple cache devices
+ *
+ * Add a sysfs tunable for the number of writeback IOs in flight
+ *
+ * Add a sysfs tunable for the number of open data buckets
+ *
+ * IO tracking: Can we track when one process is doing io on behalf of another?
+ * IO tracking: Don't use just an average, weigh more recent stuff higher
+ *
+ * Test module load/unload
+ */
+
+#define MAX_NEED_GC 64
+#define MAX_SAVE_PRIO 72
+#define MAX_GC_TIMES 100
+#define MIN_GC_NODES 100
+#define GC_SLEEP_MS 100
+
+#define PTR_DIRTY_BIT (((uint64_t) 1 << 36))
+
+#define PTR_HASH(c, k) \
+ (((k)->ptr[0] >> c->bucket_bits) | PTR_GEN(k, 0))
+
+#define insert_lock(s, b) ((b)->level <= (s)->lock)
+
+/*
+ * These macros are for recursing down the btree - they handle the details of
+ * locking and looking up nodes in the cache for you. They're best treated as
+ * mere syntax when reading code that uses them.
+ *
+ * op->lock determines whether we take a read or a write lock at a given depth.
+ * If you've got a read lock and find that you need a write lock (i.e. you're
+ * going to have to split), set op->lock and return -EINTR; btree_root() will
+ * call you again and you'll have the correct lock.
+ */
+
+/**
+ * btree - recurse down the btree on a specified key
+ * @fn: function to call, which will be passed the child node
+ * @key: key to recurse on
+ * @b: parent btree node
+ * @op: pointer to struct btree_op
+ */
+#define btree(fn, key, b, op, ...) \
+({ \
+ int _r, l = (b)->level - 1; \
+ bool _w = l <= (op)->lock; \
+ struct btree *_child = bch_btree_node_get((b)->c, op, key, l, \
+ _w, b); \
+ if (!IS_ERR(_child)) { \
+ _r = bch_btree_ ## fn(_child, op, ##__VA_ARGS__); \
+ rw_unlock(_w, _child); \
+ } else \
+ _r = PTR_ERR(_child); \
+ _r; \
+})
+
+/**
+ * btree_root - call a function on the root of the btree
+ * @fn: function to call, which will be passed the child node
+ * @c: cache set
+ * @op: pointer to struct btree_op
+ */
+#define btree_root(fn, c, op, ...) \
+({ \
+ int _r = -EINTR; \
+ do { \
+ struct btree *_b = (c)->root; \
+ bool _w = insert_lock(op, _b); \
+ rw_lock(_w, _b, _b->level); \
+ if (_b == (c)->root && \
+ _w == insert_lock(op, _b)) { \
+ _r = bch_btree_ ## fn(_b, op, ##__VA_ARGS__); \
+ } \
+ rw_unlock(_w, _b); \
+ bch_cannibalize_unlock(c); \
+ if (_r == -EINTR) \
+ schedule(); \
+ } while (_r == -EINTR); \
+ \
+ finish_wait(&(c)->btree_cache_wait, &(op)->wait); \
+ _r; \
+})
+
+static inline struct bset *write_block(struct btree *b)
+{
+ return ((void *) btree_bset_first(b)) + b->written * block_bytes(b->c);
+}
+
+static void bch_btree_init_next(struct btree *b)
+{
+ /* If not a leaf node, always sort */
+ if (b->level && b->keys.nsets)
+ bch_btree_sort(&b->keys, &b->c->sort);
+ else
+ bch_btree_sort_lazy(&b->keys, &b->c->sort);
+
+ if (b->written < btree_blocks(b))
+ bch_bset_init_next(&b->keys, write_block(b),
+ bset_magic(&b->c->sb));
+
+}
+
+/* Btree key manipulation */
+
+void bkey_put(struct cache_set *c, struct bkey *k)
+{
+ unsigned int i;
+
+ for (i = 0; i < KEY_PTRS(k); i++)
+ if (ptr_available(c, k, i))
+ atomic_dec_bug(&PTR_BUCKET(c, k, i)->pin);
+}
+
+/* Btree IO */
+
+static uint64_t btree_csum_set(struct btree *b, struct bset *i)
+{
+ uint64_t crc = b->key.ptr[0];
+ void *data = (void *) i + 8, *end = bset_bkey_last(i);
+
+ crc = bch_crc64_update(crc, data, end - data);
+ return crc ^ 0xffffffffffffffffULL;
+}
+
+void bch_btree_node_read_done(struct btree *b)
+{
+ const char *err = "bad btree header";
+ struct bset *i = btree_bset_first(b);
+ struct btree_iter *iter;
+
+ iter = mempool_alloc(&b->c->fill_iter, GFP_NOIO);
+ iter->size = b->c->sb.bucket_size / b->c->sb.block_size;
+ iter->used = 0;
+
+#ifdef CONFIG_BCACHE_DEBUG
+ iter->b = &b->keys;
+#endif
+
+ if (!i->seq)
+ goto err;
+
+ for (;
+ b->written < btree_blocks(b) && i->seq == b->keys.set[0].data->seq;
+ i = write_block(b)) {
+ err = "unsupported bset version";
+ if (i->version > BCACHE_BSET_VERSION)
+ goto err;
+
+ err = "bad btree header";
+ if (b->written + set_blocks(i, block_bytes(b->c)) >
+ btree_blocks(b))
+ goto err;
+
+ err = "bad magic";
+ if (i->magic != bset_magic(&b->c->sb))
+ goto err;
+
+ err = "bad checksum";
+ switch (i->version) {
+ case 0:
+ if (i->csum != csum_set(i))
+ goto err;
+ break;
+ case BCACHE_BSET_VERSION:
+ if (i->csum != btree_csum_set(b, i))
+ goto err;
+ break;
+ }
+
+ err = "empty set";
+ if (i != b->keys.set[0].data && !i->keys)
+ goto err;
+
+ bch_btree_iter_push(iter, i->start, bset_bkey_last(i));
+
+ b->written += set_blocks(i, block_bytes(b->c));
+ }
+
+ err = "corrupted btree";
+ for (i = write_block(b);
+ bset_sector_offset(&b->keys, i) < KEY_SIZE(&b->key);
+ i = ((void *) i) + block_bytes(b->c))
+ if (i->seq == b->keys.set[0].data->seq)
+ goto err;
+
+ bch_btree_sort_and_fix_extents(&b->keys, iter, &b->c->sort);
+
+ i = b->keys.set[0].data;
+ err = "short btree key";
+ if (b->keys.set[0].size &&
+ bkey_cmp(&b->key, &b->keys.set[0].end) < 0)
+ goto err;
+
+ if (b->written < btree_blocks(b))
+ bch_bset_init_next(&b->keys, write_block(b),
+ bset_magic(&b->c->sb));
+out:
+ mempool_free(iter, &b->c->fill_iter);
+ return;
+err:
+ set_btree_node_io_error(b);
+ bch_cache_set_error(b->c, "%s at bucket %zu, block %u, %u keys",
+ err, PTR_BUCKET_NR(b->c, &b->key, 0),
+ bset_block_offset(b, i), i->keys);
+ goto out;
+}
+
+static void btree_node_read_endio(struct bio *bio)
+{
+ struct closure *cl = bio->bi_private;
+
+ closure_put(cl);
+}
+
+static void bch_btree_node_read(struct btree *b)
+{
+ uint64_t start_time = local_clock();
+ struct closure cl;
+ struct bio *bio;
+
+ trace_bcache_btree_read(b);
+
+ closure_init_stack(&cl);
+
+ bio = bch_bbio_alloc(b->c);
+ bio->bi_iter.bi_size = KEY_SIZE(&b->key) << 9;
+ bio->bi_end_io = btree_node_read_endio;
+ bio->bi_private = &cl;
+ bio->bi_opf = REQ_OP_READ | REQ_META;
+
+ bch_bio_map(bio, b->keys.set[0].data);
+
+ bch_submit_bbio(bio, b->c, &b->key, 0);
+ closure_sync(&cl);
+
+ if (bio->bi_status)
+ set_btree_node_io_error(b);
+
+ bch_bbio_free(bio, b->c);
+
+ if (btree_node_io_error(b))
+ goto err;
+
+ bch_btree_node_read_done(b);
+ bch_time_stats_update(&b->c->btree_read_time, start_time);
+
+ return;
+err:
+ bch_cache_set_error(b->c, "io error reading bucket %zu",
+ PTR_BUCKET_NR(b->c, &b->key, 0));
+}
+
+static void btree_complete_write(struct btree *b, struct btree_write *w)
+{
+ if (w->prio_blocked &&
+ !atomic_sub_return(w->prio_blocked, &b->c->prio_blocked))
+ wake_up_allocators(b->c);
+
+ if (w->journal) {
+ atomic_dec_bug(w->journal);
+ __closure_wake_up(&b->c->journal.wait);
+ }
+
+ w->prio_blocked = 0;
+ w->journal = NULL;
+}
+
+static void btree_node_write_unlock(struct closure *cl)
+{
+ struct btree *b = container_of(cl, struct btree, io);
+
+ up(&b->io_mutex);
+}
+
+static void __btree_node_write_done(struct closure *cl)
+{
+ struct btree *b = container_of(cl, struct btree, io);
+ struct btree_write *w = btree_prev_write(b);
+
+ bch_bbio_free(b->bio, b->c);
+ b->bio = NULL;
+ btree_complete_write(b, w);
+
+ if (btree_node_dirty(b))
+ schedule_delayed_work(&b->work, 30 * HZ);
+
+ closure_return_with_destructor(cl, btree_node_write_unlock);
+}
+
+static void btree_node_write_done(struct closure *cl)
+{
+ struct btree *b = container_of(cl, struct btree, io);
+
+ bio_free_pages(b->bio);
+ __btree_node_write_done(cl);
+}
+
+static void btree_node_write_endio(struct bio *bio)
+{
+ struct closure *cl = bio->bi_private;
+ struct btree *b = container_of(cl, struct btree, io);
+
+ if (bio->bi_status)
+ set_btree_node_io_error(b);
+
+ bch_bbio_count_io_errors(b->c, bio, bio->bi_status, "writing btree");
+ closure_put(cl);
+}
+
+static void do_btree_node_write(struct btree *b)
+{
+ struct closure *cl = &b->io;
+ struct bset *i = btree_bset_last(b);
+ BKEY_PADDED(key) k;
+
+ i->version = BCACHE_BSET_VERSION;
+ i->csum = btree_csum_set(b, i);
+
+ BUG_ON(b->bio);
+ b->bio = bch_bbio_alloc(b->c);
+
+ b->bio->bi_end_io = btree_node_write_endio;
+ b->bio->bi_private = cl;
+ b->bio->bi_iter.bi_size = roundup(set_bytes(i), block_bytes(b->c));
+ b->bio->bi_opf = REQ_OP_WRITE | REQ_META | REQ_FUA;
+ bch_bio_map(b->bio, i);
+
+ /*
+ * If we're appending to a leaf node, we don't technically need FUA -
+ * this write just needs to be persisted before the next journal write,
+ * which will be marked FLUSH|FUA.
+ *
+ * Similarly if we're writing a new btree root - the pointer is going to
+ * be in the next journal entry.
+ *
+ * But if we're writing a new btree node (that isn't a root) or
+ * appending to a non leaf btree node, we need either FUA or a flush
+ * when we write the parent with the new pointer. FUA is cheaper than a
+ * flush, and writes appending to leaf nodes aren't blocking anything so
+ * just make all btree node writes FUA to keep things sane.
+ */
+
+ bkey_copy(&k.key, &b->key);
+ SET_PTR_OFFSET(&k.key, 0, PTR_OFFSET(&k.key, 0) +
+ bset_sector_offset(&b->keys, i));
+
+ if (!bch_bio_alloc_pages(b->bio, __GFP_NOWARN|GFP_NOWAIT)) {
+ int j;
+ struct bio_vec *bv;
+ void *base = (void *) ((unsigned long) i & ~(PAGE_SIZE - 1));
+
+ bio_for_each_segment_all(bv, b->bio, j)
+ memcpy(page_address(bv->bv_page),
+ base + j * PAGE_SIZE, PAGE_SIZE);
+
+ bch_submit_bbio(b->bio, b->c, &k.key, 0);
+
+ continue_at(cl, btree_node_write_done, NULL);
+ } else {
+ /*
+ * No problem for multipage bvec since the bio is
+ * just allocated
+ */
+ b->bio->bi_vcnt = 0;
+ bch_bio_map(b->bio, i);
+
+ bch_submit_bbio(b->bio, b->c, &k.key, 0);
+
+ closure_sync(cl);
+ continue_at_nobarrier(cl, __btree_node_write_done, NULL);
+ }
+}
+
+void __bch_btree_node_write(struct btree *b, struct closure *parent)
+{
+ struct bset *i = btree_bset_last(b);
+
+ lockdep_assert_held(&b->write_lock);
+
+ trace_bcache_btree_write(b);
+
+ BUG_ON(current->bio_list);
+ BUG_ON(b->written >= btree_blocks(b));
+ BUG_ON(b->written && !i->keys);
+ BUG_ON(btree_bset_first(b)->seq != i->seq);
+ bch_check_keys(&b->keys, "writing");
+
+ cancel_delayed_work(&b->work);
+
+ /* If caller isn't waiting for write, parent refcount is cache set */
+ down(&b->io_mutex);
+ closure_init(&b->io, parent ?: &b->c->cl);
+
+ clear_bit(BTREE_NODE_dirty, &b->flags);
+ change_bit(BTREE_NODE_write_idx, &b->flags);
+
+ do_btree_node_write(b);
+
+ atomic_long_add(set_blocks(i, block_bytes(b->c)) * b->c->sb.block_size,
+ &PTR_CACHE(b->c, &b->key, 0)->btree_sectors_written);
+
+ b->written += set_blocks(i, block_bytes(b->c));
+}
+
+void bch_btree_node_write(struct btree *b, struct closure *parent)
+{
+ unsigned int nsets = b->keys.nsets;
+
+ lockdep_assert_held(&b->lock);
+
+ __bch_btree_node_write(b, parent);
+
+ /*
+ * do verify if there was more than one set initially (i.e. we did a
+ * sort) and we sorted down to a single set:
+ */
+ if (nsets && !b->keys.nsets)
+ bch_btree_verify(b);
+
+ bch_btree_init_next(b);
+}
+
+static void bch_btree_node_write_sync(struct btree *b)
+{
+ struct closure cl;
+
+ closure_init_stack(&cl);
+
+ mutex_lock(&b->write_lock);
+ bch_btree_node_write(b, &cl);
+ mutex_unlock(&b->write_lock);
+
+ closure_sync(&cl);
+}
+
+static void btree_node_write_work(struct work_struct *w)
+{
+ struct btree *b = container_of(to_delayed_work(w), struct btree, work);
+
+ mutex_lock(&b->write_lock);
+ if (btree_node_dirty(b))
+ __bch_btree_node_write(b, NULL);
+ mutex_unlock(&b->write_lock);
+}
+
+static void bch_btree_leaf_dirty(struct btree *b, atomic_t *journal_ref)
+{
+ struct bset *i = btree_bset_last(b);
+ struct btree_write *w = btree_current_write(b);
+
+ lockdep_assert_held(&b->write_lock);
+
+ BUG_ON(!b->written);
+ BUG_ON(!i->keys);
+
+ if (!btree_node_dirty(b))
+ schedule_delayed_work(&b->work, 30 * HZ);
+
+ set_btree_node_dirty(b);
+
+ if (journal_ref) {
+ if (w->journal &&
+ journal_pin_cmp(b->c, w->journal, journal_ref)) {
+ atomic_dec_bug(w->journal);
+ w->journal = NULL;
+ }
+
+ if (!w->journal) {
+ w->journal = journal_ref;
+ atomic_inc(w->journal);
+ }
+ }
+
+ /* Force write if set is too big */
+ if (set_bytes(i) > PAGE_SIZE - 48 &&
+ !current->bio_list)
+ bch_btree_node_write(b, NULL);
+}
+
+/*
+ * Btree in memory cache - allocation/freeing
+ * mca -> memory cache
+ */
+
+#define mca_reserve(c) (((c->root && c->root->level) \
+ ? c->root->level : 1) * 8 + 16)
+#define mca_can_free(c) \
+ max_t(int, 0, c->btree_cache_used - mca_reserve(c))
+
+static void mca_data_free(struct btree *b)
+{
+ BUG_ON(b->io_mutex.count != 1);
+
+ bch_btree_keys_free(&b->keys);
+
+ b->c->btree_cache_used--;
+ list_move(&b->list, &b->c->btree_cache_freed);
+}
+
+static void mca_bucket_free(struct btree *b)
+{
+ BUG_ON(btree_node_dirty(b));
+
+ b->key.ptr[0] = 0;
+ hlist_del_init_rcu(&b->hash);
+ list_move(&b->list, &b->c->btree_cache_freeable);
+}
+
+static unsigned int btree_order(struct bkey *k)
+{
+ return ilog2(KEY_SIZE(k) / PAGE_SECTORS ?: 1);
+}
+
+static void mca_data_alloc(struct btree *b, struct bkey *k, gfp_t gfp)
+{
+ if (!bch_btree_keys_alloc(&b->keys,
+ max_t(unsigned int,
+ ilog2(b->c->btree_pages),
+ btree_order(k)),
+ gfp)) {
+ b->c->btree_cache_used++;
+ list_move(&b->list, &b->c->btree_cache);
+ } else {
+ list_move(&b->list, &b->c->btree_cache_freed);
+ }
+}
+
+static struct btree *mca_bucket_alloc(struct cache_set *c,
+ struct bkey *k, gfp_t gfp)
+{
+ struct btree *b = kzalloc(sizeof(struct btree), gfp);
+
+ if (!b)
+ return NULL;
+
+ init_rwsem(&b->lock);
+ lockdep_set_novalidate_class(&b->lock);
+ mutex_init(&b->write_lock);
+ lockdep_set_novalidate_class(&b->write_lock);
+ INIT_LIST_HEAD(&b->list);
+ INIT_DELAYED_WORK(&b->work, btree_node_write_work);
+ b->c = c;
+ sema_init(&b->io_mutex, 1);
+
+ mca_data_alloc(b, k, gfp);
+ return b;
+}
+
+static int mca_reap(struct btree *b, unsigned int min_order, bool flush)
+{
+ struct closure cl;
+
+ closure_init_stack(&cl);
+ lockdep_assert_held(&b->c->bucket_lock);
+
+ if (!down_write_trylock(&b->lock))
+ return -ENOMEM;
+
+ BUG_ON(btree_node_dirty(b) && !b->keys.set[0].data);
+
+ if (b->keys.page_order < min_order)
+ goto out_unlock;
+
+ if (!flush) {
+ if (btree_node_dirty(b))
+ goto out_unlock;
+
+ if (down_trylock(&b->io_mutex))
+ goto out_unlock;
+ up(&b->io_mutex);
+ }
+
+ mutex_lock(&b->write_lock);
+ if (btree_node_dirty(b))
+ __bch_btree_node_write(b, &cl);
+ mutex_unlock(&b->write_lock);
+
+ closure_sync(&cl);
+
+ /* wait for any in flight btree write */
+ down(&b->io_mutex);
+ up(&b->io_mutex);
+
+ return 0;
+out_unlock:
+ rw_unlock(true, b);
+ return -ENOMEM;
+}
+
+static unsigned long bch_mca_scan(struct shrinker *shrink,
+ struct shrink_control *sc)
+{
+ struct cache_set *c = container_of(shrink, struct cache_set, shrink);
+ struct btree *b, *t;
+ unsigned long i, nr = sc->nr_to_scan;
+ unsigned long freed = 0;
+ unsigned int btree_cache_used;
+
+ if (c->shrinker_disabled)
+ return SHRINK_STOP;
+
+ if (c->btree_cache_alloc_lock)
+ return SHRINK_STOP;
+
+ /* Return -1 if we can't do anything right now */
+ if (sc->gfp_mask & __GFP_IO)
+ mutex_lock(&c->bucket_lock);
+ else if (!mutex_trylock(&c->bucket_lock))
+ return -1;
+
+ /*
+ * It's _really_ critical that we don't free too many btree nodes - we
+ * have to always leave ourselves a reserve. The reserve is how we
+ * guarantee that allocating memory for a new btree node can always
+ * succeed, so that inserting keys into the btree can always succeed and
+ * IO can always make forward progress:
+ */
+ nr /= c->btree_pages;
+ nr = min_t(unsigned long, nr, mca_can_free(c));
+
+ i = 0;
+ btree_cache_used = c->btree_cache_used;
+ list_for_each_entry_safe(b, t, &c->btree_cache_freeable, list) {
+ if (nr <= 0)
+ goto out;
+
+ if (++i > 3 &&
+ !mca_reap(b, 0, false)) {
+ mca_data_free(b);
+ rw_unlock(true, b);
+ freed++;
+ }
+ nr--;
+ }
+
+ for (; (nr--) && i < btree_cache_used; i++) {
+ if (list_empty(&c->btree_cache))
+ goto out;
+
+ b = list_first_entry(&c->btree_cache, struct btree, list);
+ list_rotate_left(&c->btree_cache);
+
+ if (!b->accessed &&
+ !mca_reap(b, 0, false)) {
+ mca_bucket_free(b);
+ mca_data_free(b);
+ rw_unlock(true, b);
+ freed++;
+ } else
+ b->accessed = 0;
+ }
+out:
+ mutex_unlock(&c->bucket_lock);
+ return freed * c->btree_pages;
+}
+
+static unsigned long bch_mca_count(struct shrinker *shrink,
+ struct shrink_control *sc)
+{
+ struct cache_set *c = container_of(shrink, struct cache_set, shrink);
+
+ if (c->shrinker_disabled)
+ return 0;
+
+ if (c->btree_cache_alloc_lock)
+ return 0;
+
+ return mca_can_free(c) * c->btree_pages;
+}
+
+void bch_btree_cache_free(struct cache_set *c)
+{
+ struct btree *b;
+ struct closure cl;
+
+ closure_init_stack(&cl);
+
+ if (c->shrink.list.next)
+ unregister_shrinker(&c->shrink);
+
+ mutex_lock(&c->bucket_lock);
+
+#ifdef CONFIG_BCACHE_DEBUG
+ if (c->verify_data)
+ list_move(&c->verify_data->list, &c->btree_cache);
+
+ free_pages((unsigned long) c->verify_ondisk, ilog2(bucket_pages(c)));
+#endif
+
+ list_splice(&c->btree_cache_freeable,
+ &c->btree_cache);
+
+ while (!list_empty(&c->btree_cache)) {
+ b = list_first_entry(&c->btree_cache, struct btree, list);
+
+ if (btree_node_dirty(b))
+ btree_complete_write(b, btree_current_write(b));
+ clear_bit(BTREE_NODE_dirty, &b->flags);
+
+ mca_data_free(b);
+ }
+
+ while (!list_empty(&c->btree_cache_freed)) {
+ b = list_first_entry(&c->btree_cache_freed,
+ struct btree, list);
+ list_del(&b->list);
+ cancel_delayed_work_sync(&b->work);
+ kfree(b);
+ }
+
+ mutex_unlock(&c->bucket_lock);
+}
+
+int bch_btree_cache_alloc(struct cache_set *c)
+{
+ unsigned int i;
+
+ for (i = 0; i < mca_reserve(c); i++)
+ if (!mca_bucket_alloc(c, &ZERO_KEY, GFP_KERNEL))
+ return -ENOMEM;
+
+ list_splice_init(&c->btree_cache,
+ &c->btree_cache_freeable);
+
+#ifdef CONFIG_BCACHE_DEBUG
+ mutex_init(&c->verify_lock);
+
+ c->verify_ondisk = (void *)
+ __get_free_pages(GFP_KERNEL, ilog2(bucket_pages(c)));
+
+ c->verify_data = mca_bucket_alloc(c, &ZERO_KEY, GFP_KERNEL);
+
+ if (c->verify_data &&
+ c->verify_data->keys.set->data)
+ list_del_init(&c->verify_data->list);
+ else
+ c->verify_data = NULL;
+#endif
+
+ c->shrink.count_objects = bch_mca_count;
+ c->shrink.scan_objects = bch_mca_scan;
+ c->shrink.seeks = 4;
+ c->shrink.batch = c->btree_pages * 2;
+
+ if (register_shrinker(&c->shrink))
+ pr_warn("bcache: %s: could not register shrinker",
+ __func__);
+
+ return 0;
+}
+
+/* Btree in memory cache - hash table */
+
+static struct hlist_head *mca_hash(struct cache_set *c, struct bkey *k)
+{
+ return &c->bucket_hash[hash_32(PTR_HASH(c, k), BUCKET_HASH_BITS)];
+}
+
+static struct btree *mca_find(struct cache_set *c, struct bkey *k)
+{
+ struct btree *b;
+
+ rcu_read_lock();
+ hlist_for_each_entry_rcu(b, mca_hash(c, k), hash)
+ if (PTR_HASH(c, &b->key) == PTR_HASH(c, k))
+ goto out;
+ b = NULL;
+out:
+ rcu_read_unlock();
+ return b;
+}
+
+static int mca_cannibalize_lock(struct cache_set *c, struct btree_op *op)
+{
+ struct task_struct *old;
+
+ old = cmpxchg(&c->btree_cache_alloc_lock, NULL, current);
+ if (old && old != current) {
+ if (op)
+ prepare_to_wait(&c->btree_cache_wait, &op->wait,
+ TASK_UNINTERRUPTIBLE);
+ return -EINTR;
+ }
+
+ return 0;
+}
+
+static struct btree *mca_cannibalize(struct cache_set *c, struct btree_op *op,
+ struct bkey *k)
+{
+ struct btree *b;
+
+ trace_bcache_btree_cache_cannibalize(c);
+
+ if (mca_cannibalize_lock(c, op))
+ return ERR_PTR(-EINTR);
+
+ list_for_each_entry_reverse(b, &c->btree_cache, list)
+ if (!mca_reap(b, btree_order(k), false))
+ return b;
+
+ list_for_each_entry_reverse(b, &c->btree_cache, list)
+ if (!mca_reap(b, btree_order(k), true))
+ return b;
+
+ WARN(1, "btree cache cannibalize failed\n");
+ return ERR_PTR(-ENOMEM);
+}
+
+/*
+ * We can only have one thread cannibalizing other cached btree nodes at a time,
+ * or we'll deadlock. We use an open coded mutex to ensure that, which a
+ * cannibalize_bucket() will take. This means every time we unlock the root of
+ * the btree, we need to release this lock if we have it held.
+ */
+static void bch_cannibalize_unlock(struct cache_set *c)
+{
+ if (c->btree_cache_alloc_lock == current) {
+ c->btree_cache_alloc_lock = NULL;
+ wake_up(&c->btree_cache_wait);
+ }
+}
+
+static struct btree *mca_alloc(struct cache_set *c, struct btree_op *op,
+ struct bkey *k, int level)
+{
+ struct btree *b;
+
+ BUG_ON(current->bio_list);
+
+ lockdep_assert_held(&c->bucket_lock);
+
+ if (mca_find(c, k))
+ return NULL;
+
+ /* btree_free() doesn't free memory; it sticks the node on the end of
+ * the list. Check if there's any freed nodes there:
+ */
+ list_for_each_entry(b, &c->btree_cache_freeable, list)
+ if (!mca_reap(b, btree_order(k), false))
+ goto out;
+
+ /* We never free struct btree itself, just the memory that holds the on
+ * disk node. Check the freed list before allocating a new one:
+ */
+ list_for_each_entry(b, &c->btree_cache_freed, list)
+ if (!mca_reap(b, 0, false)) {
+ mca_data_alloc(b, k, __GFP_NOWARN|GFP_NOIO);
+ if (!b->keys.set[0].data)
+ goto err;
+ else
+ goto out;
+ }
+
+ b = mca_bucket_alloc(c, k, __GFP_NOWARN|GFP_NOIO);
+ if (!b)
+ goto err;
+
+ BUG_ON(!down_write_trylock(&b->lock));
+ if (!b->keys.set->data)
+ goto err;
+out:
+ BUG_ON(b->io_mutex.count != 1);
+
+ bkey_copy(&b->key, k);
+ list_move(&b->list, &c->btree_cache);
+ hlist_del_init_rcu(&b->hash);
+ hlist_add_head_rcu(&b->hash, mca_hash(c, k));
+
+ lock_set_subclass(&b->lock.dep_map, level + 1, _THIS_IP_);
+ b->parent = (void *) ~0UL;
+ b->flags = 0;
+ b->written = 0;
+ b->level = level;
+
+ if (!b->level)
+ bch_btree_keys_init(&b->keys, &bch_extent_keys_ops,
+ &b->c->expensive_debug_checks);
+ else
+ bch_btree_keys_init(&b->keys, &bch_btree_keys_ops,
+ &b->c->expensive_debug_checks);
+
+ return b;
+err:
+ if (b)
+ rw_unlock(true, b);
+
+ b = mca_cannibalize(c, op, k);
+ if (!IS_ERR(b))
+ goto out;
+
+ return b;
+}
+
+/*
+ * bch_btree_node_get - find a btree node in the cache and lock it, reading it
+ * in from disk if necessary.
+ *
+ * If IO is necessary and running under generic_make_request, returns -EAGAIN.
+ *
+ * The btree node will have either a read or a write lock held, depending on
+ * level and op->lock.
+ */
+struct btree *bch_btree_node_get(struct cache_set *c, struct btree_op *op,
+ struct bkey *k, int level, bool write,
+ struct btree *parent)
+{
+ int i = 0;
+ struct btree *b;
+
+ BUG_ON(level < 0);
+retry:
+ b = mca_find(c, k);
+
+ if (!b) {
+ if (current->bio_list)
+ return ERR_PTR(-EAGAIN);
+
+ mutex_lock(&c->bucket_lock);
+ b = mca_alloc(c, op, k, level);
+ mutex_unlock(&c->bucket_lock);
+
+ if (!b)
+ goto retry;
+ if (IS_ERR(b))
+ return b;
+
+ bch_btree_node_read(b);
+
+ if (!write)
+ downgrade_write(&b->lock);
+ } else {
+ rw_lock(write, b, level);
+ if (PTR_HASH(c, &b->key) != PTR_HASH(c, k)) {
+ rw_unlock(write, b);
+ goto retry;
+ }
+ BUG_ON(b->level != level);
+ }
+
+ if (btree_node_io_error(b)) {
+ rw_unlock(write, b);
+ return ERR_PTR(-EIO);
+ }
+
+ BUG_ON(!b->written);
+
+ b->parent = parent;
+ b->accessed = 1;
+
+ for (; i <= b->keys.nsets && b->keys.set[i].size; i++) {
+ prefetch(b->keys.set[i].tree);
+ prefetch(b->keys.set[i].data);
+ }
+
+ for (; i <= b->keys.nsets; i++)
+ prefetch(b->keys.set[i].data);
+
+ return b;
+}
+
+static void btree_node_prefetch(struct btree *parent, struct bkey *k)
+{
+ struct btree *b;
+
+ mutex_lock(&parent->c->bucket_lock);
+ b = mca_alloc(parent->c, NULL, k, parent->level - 1);
+ mutex_unlock(&parent->c->bucket_lock);
+
+ if (!IS_ERR_OR_NULL(b)) {
+ b->parent = parent;
+ bch_btree_node_read(b);
+ rw_unlock(true, b);
+ }
+}
+
+/* Btree alloc */
+
+static void btree_node_free(struct btree *b)
+{
+ trace_bcache_btree_node_free(b);
+
+ BUG_ON(b == b->c->root);
+
+ mutex_lock(&b->write_lock);
+
+ if (btree_node_dirty(b))
+ btree_complete_write(b, btree_current_write(b));
+ clear_bit(BTREE_NODE_dirty, &b->flags);
+
+ mutex_unlock(&b->write_lock);
+
+ cancel_delayed_work(&b->work);
+
+ mutex_lock(&b->c->bucket_lock);
+ bch_bucket_free(b->c, &b->key);
+ mca_bucket_free(b);
+ mutex_unlock(&b->c->bucket_lock);
+}
+
+struct btree *__bch_btree_node_alloc(struct cache_set *c, struct btree_op *op,
+ int level, bool wait,
+ struct btree *parent)
+{
+ BKEY_PADDED(key) k;
+ struct btree *b = ERR_PTR(-EAGAIN);
+
+ mutex_lock(&c->bucket_lock);
+retry:
+ if (__bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, 1, wait))
+ goto err;
+
+ bkey_put(c, &k.key);
+ SET_KEY_SIZE(&k.key, c->btree_pages * PAGE_SECTORS);
+
+ b = mca_alloc(c, op, &k.key, level);
+ if (IS_ERR(b))
+ goto err_free;
+
+ if (!b) {
+ cache_bug(c,
+ "Tried to allocate bucket that was in btree cache");
+ goto retry;
+ }
+
+ b->accessed = 1;
+ b->parent = parent;
+ bch_bset_init_next(&b->keys, b->keys.set->data, bset_magic(&b->c->sb));
+
+ mutex_unlock(&c->bucket_lock);
+
+ trace_bcache_btree_node_alloc(b);
+ return b;
+err_free:
+ bch_bucket_free(c, &k.key);
+err:
+ mutex_unlock(&c->bucket_lock);
+
+ trace_bcache_btree_node_alloc_fail(c);
+ return b;
+}
+
+static struct btree *bch_btree_node_alloc(struct cache_set *c,
+ struct btree_op *op, int level,
+ struct btree *parent)
+{
+ return __bch_btree_node_alloc(c, op, level, op != NULL, parent);
+}
+
+static struct btree *btree_node_alloc_replacement(struct btree *b,
+ struct btree_op *op)
+{
+ struct btree *n = bch_btree_node_alloc(b->c, op, b->level, b->parent);
+
+ if (!IS_ERR_OR_NULL(n)) {
+ mutex_lock(&n->write_lock);
+ bch_btree_sort_into(&b->keys, &n->keys, &b->c->sort);
+ bkey_copy_key(&n->key, &b->key);
+ mutex_unlock(&n->write_lock);
+ }
+
+ return n;
+}
+
+static void make_btree_freeing_key(struct btree *b, struct bkey *k)
+{
+ unsigned int i;
+
+ mutex_lock(&b->c->bucket_lock);
+
+ atomic_inc(&b->c->prio_blocked);
+
+ bkey_copy(k, &b->key);
+ bkey_copy_key(k, &ZERO_KEY);
+
+ for (i = 0; i < KEY_PTRS(k); i++)
+ SET_PTR_GEN(k, i,
+ bch_inc_gen(PTR_CACHE(b->c, &b->key, i),
+ PTR_BUCKET(b->c, &b->key, i)));
+
+ mutex_unlock(&b->c->bucket_lock);
+}
+
+static int btree_check_reserve(struct btree *b, struct btree_op *op)
+{
+ struct cache_set *c = b->c;
+ struct cache *ca;
+ unsigned int i, reserve = (c->root->level - b->level) * 2 + 1;
+
+ mutex_lock(&c->bucket_lock);
+
+ for_each_cache(ca, c, i)
+ if (fifo_used(&ca->free[RESERVE_BTREE]) < reserve) {
+ if (op)
+ prepare_to_wait(&c->btree_cache_wait, &op->wait,
+ TASK_UNINTERRUPTIBLE);
+ mutex_unlock(&c->bucket_lock);
+ return -EINTR;
+ }
+
+ mutex_unlock(&c->bucket_lock);
+
+ return mca_cannibalize_lock(b->c, op);
+}
+
+/* Garbage collection */
+
+static uint8_t __bch_btree_mark_key(struct cache_set *c, int level,
+ struct bkey *k)
+{
+ uint8_t stale = 0;
+ unsigned int i;
+ struct bucket *g;
+
+ /*
+ * ptr_invalid() can't return true for the keys that mark btree nodes as
+ * freed, but since ptr_bad() returns true we'll never actually use them
+ * for anything and thus we don't want mark their pointers here
+ */
+ if (!bkey_cmp(k, &ZERO_KEY))
+ return stale;
+
+ for (i = 0; i < KEY_PTRS(k); i++) {
+ if (!ptr_available(c, k, i))
+ continue;
+
+ g = PTR_BUCKET(c, k, i);
+
+ if (gen_after(g->last_gc, PTR_GEN(k, i)))
+ g->last_gc = PTR_GEN(k, i);
+
+ if (ptr_stale(c, k, i)) {
+ stale = max(stale, ptr_stale(c, k, i));
+ continue;
+ }
+
+ cache_bug_on(GC_MARK(g) &&
+ (GC_MARK(g) == GC_MARK_METADATA) != (level != 0),
+ c, "inconsistent ptrs: mark = %llu, level = %i",
+ GC_MARK(g), level);
+
+ if (level)
+ SET_GC_MARK(g, GC_MARK_METADATA);
+ else if (KEY_DIRTY(k))
+ SET_GC_MARK(g, GC_MARK_DIRTY);
+ else if (!GC_MARK(g))
+ SET_GC_MARK(g, GC_MARK_RECLAIMABLE);
+
+ /* guard against overflow */
+ SET_GC_SECTORS_USED(g, min_t(unsigned int,
+ GC_SECTORS_USED(g) + KEY_SIZE(k),
+ MAX_GC_SECTORS_USED));
+
+ BUG_ON(!GC_SECTORS_USED(g));
+ }
+
+ return stale;
+}
+
+#define btree_mark_key(b, k) __bch_btree_mark_key(b->c, b->level, k)
+
+void bch_initial_mark_key(struct cache_set *c, int level, struct bkey *k)
+{
+ unsigned int i;
+
+ for (i = 0; i < KEY_PTRS(k); i++)
+ if (ptr_available(c, k, i) &&
+ !ptr_stale(c, k, i)) {
+ struct bucket *b = PTR_BUCKET(c, k, i);
+
+ b->gen = PTR_GEN(k, i);
+
+ if (level && bkey_cmp(k, &ZERO_KEY))
+ b->prio = BTREE_PRIO;
+ else if (!level && b->prio == BTREE_PRIO)
+ b->prio = INITIAL_PRIO;
+ }
+
+ __bch_btree_mark_key(c, level, k);
+}
+
+void bch_update_bucket_in_use(struct cache_set *c, struct gc_stat *stats)
+{
+ stats->in_use = (c->nbuckets - c->avail_nbuckets) * 100 / c->nbuckets;
+}
+
+static bool btree_gc_mark_node(struct btree *b, struct gc_stat *gc)
+{
+ uint8_t stale = 0;
+ unsigned int keys = 0, good_keys = 0;
+ struct bkey *k;
+ struct btree_iter iter;
+ struct bset_tree *t;
+
+ gc->nodes++;
+
+ for_each_key_filter(&b->keys, k, &iter, bch_ptr_invalid) {
+ stale = max(stale, btree_mark_key(b, k));
+ keys++;
+
+ if (bch_ptr_bad(&b->keys, k))
+ continue;
+
+ gc->key_bytes += bkey_u64s(k);
+ gc->nkeys++;
+ good_keys++;
+
+ gc->data += KEY_SIZE(k);
+ }
+
+ for (t = b->keys.set; t <= &b->keys.set[b->keys.nsets]; t++)
+ btree_bug_on(t->size &&
+ bset_written(&b->keys, t) &&
+ bkey_cmp(&b->key, &t->end) < 0,
+ b, "found short btree key in gc");
+
+ if (b->c->gc_always_rewrite)
+ return true;
+
+ if (stale > 10)
+ return true;
+
+ if ((keys - good_keys) * 2 > keys)
+ return true;
+
+ return false;
+}
+
+#define GC_MERGE_NODES 4U
+
+struct gc_merge_info {
+ struct btree *b;
+ unsigned int keys;
+};
+
+static int bch_btree_insert_node(struct btree *b, struct btree_op *op,
+ struct keylist *insert_keys,
+ atomic_t *journal_ref,
+ struct bkey *replace_key);
+
+static int btree_gc_coalesce(struct btree *b, struct btree_op *op,
+ struct gc_stat *gc, struct gc_merge_info *r)
+{
+ unsigned int i, nodes = 0, keys = 0, blocks;
+ struct btree *new_nodes[GC_MERGE_NODES];
+ struct keylist keylist;
+ struct closure cl;
+ struct bkey *k;
+
+ bch_keylist_init(&keylist);
+
+ if (btree_check_reserve(b, NULL))
+ return 0;
+
+ memset(new_nodes, 0, sizeof(new_nodes));
+ closure_init_stack(&cl);
+
+ while (nodes < GC_MERGE_NODES && !IS_ERR_OR_NULL(r[nodes].b))
+ keys += r[nodes++].keys;
+
+ blocks = btree_default_blocks(b->c) * 2 / 3;
+
+ if (nodes < 2 ||
+ __set_blocks(b->keys.set[0].data, keys,
+ block_bytes(b->c)) > blocks * (nodes - 1))
+ return 0;
+
+ for (i = 0; i < nodes; i++) {
+ new_nodes[i] = btree_node_alloc_replacement(r[i].b, NULL);
+ if (IS_ERR_OR_NULL(new_nodes[i]))
+ goto out_nocoalesce;
+ }
+
+ /*
+ * We have to check the reserve here, after we've allocated our new
+ * nodes, to make sure the insert below will succeed - we also check
+ * before as an optimization to potentially avoid a bunch of expensive
+ * allocs/sorts
+ */
+ if (btree_check_reserve(b, NULL))
+ goto out_nocoalesce;
+
+ for (i = 0; i < nodes; i++)
+ mutex_lock(&new_nodes[i]->write_lock);
+
+ for (i = nodes - 1; i > 0; --i) {
+ struct bset *n1 = btree_bset_first(new_nodes[i]);
+ struct bset *n2 = btree_bset_first(new_nodes[i - 1]);
+ struct bkey *k, *last = NULL;
+
+ keys = 0;
+
+ if (i > 1) {
+ for (k = n2->start;
+ k < bset_bkey_last(n2);
+ k = bkey_next(k)) {
+ if (__set_blocks(n1, n1->keys + keys +
+ bkey_u64s(k),
+ block_bytes(b->c)) > blocks)
+ break;
+
+ last = k;
+ keys += bkey_u64s(k);
+ }
+ } else {
+ /*
+ * Last node we're not getting rid of - we're getting
+ * rid of the node at r[0]. Have to try and fit all of
+ * the remaining keys into this node; we can't ensure
+ * they will always fit due to rounding and variable
+ * length keys (shouldn't be possible in practice,
+ * though)
+ */
+ if (__set_blocks(n1, n1->keys + n2->keys,
+ block_bytes(b->c)) >
+ btree_blocks(new_nodes[i]))
+ goto out_nocoalesce;
+
+ keys = n2->keys;
+ /* Take the key of the node we're getting rid of */
+ last = &r->b->key;
+ }
+
+ BUG_ON(__set_blocks(n1, n1->keys + keys, block_bytes(b->c)) >
+ btree_blocks(new_nodes[i]));
+
+ if (last)
+ bkey_copy_key(&new_nodes[i]->key, last);
+
+ memcpy(bset_bkey_last(n1),
+ n2->start,
+ (void *) bset_bkey_idx(n2, keys) - (void *) n2->start);
+
+ n1->keys += keys;
+ r[i].keys = n1->keys;
+
+ memmove(n2->start,
+ bset_bkey_idx(n2, keys),
+ (void *) bset_bkey_last(n2) -
+ (void *) bset_bkey_idx(n2, keys));
+
+ n2->keys -= keys;
+
+ if (__bch_keylist_realloc(&keylist,
+ bkey_u64s(&new_nodes[i]->key)))
+ goto out_nocoalesce;
+
+ bch_btree_node_write(new_nodes[i], &cl);
+ bch_keylist_add(&keylist, &new_nodes[i]->key);
+ }
+
+ for (i = 0; i < nodes; i++)
+ mutex_unlock(&new_nodes[i]->write_lock);
+
+ closure_sync(&cl);
+
+ /* We emptied out this node */
+ BUG_ON(btree_bset_first(new_nodes[0])->keys);
+ btree_node_free(new_nodes[0]);
+ rw_unlock(true, new_nodes[0]);
+ new_nodes[0] = NULL;
+
+ for (i = 0; i < nodes; i++) {
+ if (__bch_keylist_realloc(&keylist, bkey_u64s(&r[i].b->key)))
+ goto out_nocoalesce;
+
+ make_btree_freeing_key(r[i].b, keylist.top);
+ bch_keylist_push(&keylist);
+ }
+
+ bch_btree_insert_node(b, op, &keylist, NULL, NULL);
+ BUG_ON(!bch_keylist_empty(&keylist));
+
+ for (i = 0; i < nodes; i++) {
+ btree_node_free(r[i].b);
+ rw_unlock(true, r[i].b);
+
+ r[i].b = new_nodes[i];
+ }
+
+ memmove(r, r + 1, sizeof(r[0]) * (nodes - 1));
+ r[nodes - 1].b = ERR_PTR(-EINTR);
+
+ trace_bcache_btree_gc_coalesce(nodes);
+ gc->nodes--;
+
+ bch_keylist_free(&keylist);
+
+ /* Invalidated our iterator */
+ return -EINTR;
+
+out_nocoalesce:
+ closure_sync(&cl);
+ bch_keylist_free(&keylist);
+
+ while ((k = bch_keylist_pop(&keylist)))
+ if (!bkey_cmp(k, &ZERO_KEY))
+ atomic_dec(&b->c->prio_blocked);
+
+ for (i = 0; i < nodes; i++)
+ if (!IS_ERR_OR_NULL(new_nodes[i])) {
+ btree_node_free(new_nodes[i]);
+ rw_unlock(true, new_nodes[i]);
+ }
+ return 0;
+}
+
+static int btree_gc_rewrite_node(struct btree *b, struct btree_op *op,
+ struct btree *replace)
+{
+ struct keylist keys;
+ struct btree *n;
+
+ if (btree_check_reserve(b, NULL))
+ return 0;
+
+ n = btree_node_alloc_replacement(replace, NULL);
+
+ /* recheck reserve after allocating replacement node */
+ if (btree_check_reserve(b, NULL)) {
+ btree_node_free(n);
+ rw_unlock(true, n);
+ return 0;
+ }
+
+ bch_btree_node_write_sync(n);
+
+ bch_keylist_init(&keys);
+ bch_keylist_add(&keys, &n->key);
+
+ make_btree_freeing_key(replace, keys.top);
+ bch_keylist_push(&keys);
+
+ bch_btree_insert_node(b, op, &keys, NULL, NULL);
+ BUG_ON(!bch_keylist_empty(&keys));
+
+ btree_node_free(replace);
+ rw_unlock(true, n);
+
+ /* Invalidated our iterator */
+ return -EINTR;
+}
+
+static unsigned int btree_gc_count_keys(struct btree *b)
+{
+ struct bkey *k;
+ struct btree_iter iter;
+ unsigned int ret = 0;
+
+ for_each_key_filter(&b->keys, k, &iter, bch_ptr_bad)
+ ret += bkey_u64s(k);
+
+ return ret;
+}
+
+static size_t btree_gc_min_nodes(struct cache_set *c)
+{
+ size_t min_nodes;
+
+ /*
+ * Since incremental GC would stop 100ms when front
+ * side I/O comes, so when there are many btree nodes,
+ * if GC only processes constant (100) nodes each time,
+ * GC would last a long time, and the front side I/Os
+ * would run out of the buckets (since no new bucket
+ * can be allocated during GC), and be blocked again.
+ * So GC should not process constant nodes, but varied
+ * nodes according to the number of btree nodes, which
+ * realized by dividing GC into constant(100) times,
+ * so when there are many btree nodes, GC can process
+ * more nodes each time, otherwise, GC will process less
+ * nodes each time (but no less than MIN_GC_NODES)
+ */
+ min_nodes = c->gc_stats.nodes / MAX_GC_TIMES;
+ if (min_nodes < MIN_GC_NODES)
+ min_nodes = MIN_GC_NODES;
+
+ return min_nodes;
+}
+
+
+static int btree_gc_recurse(struct btree *b, struct btree_op *op,
+ struct closure *writes, struct gc_stat *gc)
+{
+ int ret = 0;
+ bool should_rewrite;
+ struct bkey *k;
+ struct btree_iter iter;
+ struct gc_merge_info r[GC_MERGE_NODES];
+ struct gc_merge_info *i, *last = r + ARRAY_SIZE(r) - 1;
+
+ bch_btree_iter_init(&b->keys, &iter, &b->c->gc_done);
+
+ for (i = r; i < r + ARRAY_SIZE(r); i++)
+ i->b = ERR_PTR(-EINTR);
+
+ while (1) {
+ k = bch_btree_iter_next_filter(&iter, &b->keys, bch_ptr_bad);
+ if (k) {
+ r->b = bch_btree_node_get(b->c, op, k, b->level - 1,
+ true, b);
+ if (IS_ERR(r->b)) {
+ ret = PTR_ERR(r->b);
+ break;
+ }
+
+ r->keys = btree_gc_count_keys(r->b);
+
+ ret = btree_gc_coalesce(b, op, gc, r);
+ if (ret)
+ break;
+ }
+
+ if (!last->b)
+ break;
+
+ if (!IS_ERR(last->b)) {
+ should_rewrite = btree_gc_mark_node(last->b, gc);
+ if (should_rewrite) {
+ ret = btree_gc_rewrite_node(b, op, last->b);
+ if (ret)
+ break;
+ }
+
+ if (last->b->level) {
+ ret = btree_gc_recurse(last->b, op, writes, gc);
+ if (ret)
+ break;
+ }
+
+ bkey_copy_key(&b->c->gc_done, &last->b->key);
+
+ /*
+ * Must flush leaf nodes before gc ends, since replace
+ * operations aren't journalled
+ */
+ mutex_lock(&last->b->write_lock);
+ if (btree_node_dirty(last->b))
+ bch_btree_node_write(last->b, writes);
+ mutex_unlock(&last->b->write_lock);
+ rw_unlock(true, last->b);
+ }
+
+ memmove(r + 1, r, sizeof(r[0]) * (GC_MERGE_NODES - 1));
+ r->b = NULL;
+
+ if (atomic_read(&b->c->search_inflight) &&
+ gc->nodes >= gc->nodes_pre + btree_gc_min_nodes(b->c)) {
+ gc->nodes_pre = gc->nodes;
+ ret = -EAGAIN;
+ break;
+ }
+
+ if (need_resched()) {
+ ret = -EAGAIN;
+ break;
+ }
+ }
+
+ for (i = r; i < r + ARRAY_SIZE(r); i++)
+ if (!IS_ERR_OR_NULL(i->b)) {
+ mutex_lock(&i->b->write_lock);
+ if (btree_node_dirty(i->b))
+ bch_btree_node_write(i->b, writes);
+ mutex_unlock(&i->b->write_lock);
+ rw_unlock(true, i->b);
+ }
+
+ return ret;
+}
+
+static int bch_btree_gc_root(struct btree *b, struct btree_op *op,
+ struct closure *writes, struct gc_stat *gc)
+{
+ struct btree *n = NULL;
+ int ret = 0;
+ bool should_rewrite;
+
+ should_rewrite = btree_gc_mark_node(b, gc);
+ if (should_rewrite) {
+ n = btree_node_alloc_replacement(b, NULL);
+
+ if (!IS_ERR_OR_NULL(n)) {
+ bch_btree_node_write_sync(n);
+
+ bch_btree_set_root(n);
+ btree_node_free(b);
+ rw_unlock(true, n);
+
+ return -EINTR;
+ }
+ }
+
+ __bch_btree_mark_key(b->c, b->level + 1, &b->key);
+
+ if (b->level) {
+ ret = btree_gc_recurse(b, op, writes, gc);
+ if (ret)
+ return ret;
+ }
+
+ bkey_copy_key(&b->c->gc_done, &b->key);
+
+ return ret;
+}
+
+static void btree_gc_start(struct cache_set *c)
+{
+ struct cache *ca;
+ struct bucket *b;
+ unsigned int i;
+
+ if (!c->gc_mark_valid)
+ return;
+
+ mutex_lock(&c->bucket_lock);
+
+ c->gc_mark_valid = 0;
+ c->gc_done = ZERO_KEY;
+
+ for_each_cache(ca, c, i)
+ for_each_bucket(b, ca) {
+ b->last_gc = b->gen;
+ if (!atomic_read(&b->pin)) {
+ SET_GC_MARK(b, 0);
+ SET_GC_SECTORS_USED(b, 0);
+ }
+ }
+
+ mutex_unlock(&c->bucket_lock);
+}
+
+static void bch_btree_gc_finish(struct cache_set *c)
+{
+ struct bucket *b;
+ struct cache *ca;
+ unsigned int i;
+
+ mutex_lock(&c->bucket_lock);
+
+ set_gc_sectors(c);
+ c->gc_mark_valid = 1;
+ c->need_gc = 0;
+
+ for (i = 0; i < KEY_PTRS(&c->uuid_bucket); i++)
+ SET_GC_MARK(PTR_BUCKET(c, &c->uuid_bucket, i),
+ GC_MARK_METADATA);
+
+ /* don't reclaim buckets to which writeback keys point */
+ rcu_read_lock();
+ for (i = 0; i < c->devices_max_used; i++) {
+ struct bcache_device *d = c->devices[i];
+ struct cached_dev *dc;
+ struct keybuf_key *w, *n;
+ unsigned int j;
+
+ if (!d || UUID_FLASH_ONLY(&c->uuids[i]))
+ continue;
+ dc = container_of(d, struct cached_dev, disk);
+
+ spin_lock(&dc->writeback_keys.lock);
+ rbtree_postorder_for_each_entry_safe(w, n,
+ &dc->writeback_keys.keys, node)
+ for (j = 0; j < KEY_PTRS(&w->key); j++)
+ SET_GC_MARK(PTR_BUCKET(c, &w->key, j),
+ GC_MARK_DIRTY);
+ spin_unlock(&dc->writeback_keys.lock);
+ }
+ rcu_read_unlock();
+
+ c->avail_nbuckets = 0;
+ for_each_cache(ca, c, i) {
+ uint64_t *i;
+
+ ca->invalidate_needs_gc = 0;
+
+ for (i = ca->sb.d; i < ca->sb.d + ca->sb.keys; i++)
+ SET_GC_MARK(ca->buckets + *i, GC_MARK_METADATA);
+
+ for (i = ca->prio_buckets;
+ i < ca->prio_buckets + prio_buckets(ca) * 2; i++)
+ SET_GC_MARK(ca->buckets + *i, GC_MARK_METADATA);
+
+ for_each_bucket(b, ca) {
+ c->need_gc = max(c->need_gc, bucket_gc_gen(b));
+
+ if (atomic_read(&b->pin))
+ continue;
+
+ BUG_ON(!GC_MARK(b) && GC_SECTORS_USED(b));
+
+ if (!GC_MARK(b) || GC_MARK(b) == GC_MARK_RECLAIMABLE)
+ c->avail_nbuckets++;
+ }
+ }
+
+ mutex_unlock(&c->bucket_lock);
+}
+
+static void bch_btree_gc(struct cache_set *c)
+{
+ int ret;
+ struct gc_stat stats;
+ struct closure writes;
+ struct btree_op op;
+ uint64_t start_time = local_clock();
+
+ trace_bcache_gc_start(c);
+
+ memset(&stats, 0, sizeof(struct gc_stat));
+ closure_init_stack(&writes);
+ bch_btree_op_init(&op, SHRT_MAX);
+
+ btree_gc_start(c);
+
+ /* if CACHE_SET_IO_DISABLE set, gc thread should stop too */
+ do {
+ ret = btree_root(gc_root, c, &op, &writes, &stats);
+ closure_sync(&writes);
+ cond_resched();
+
+ if (ret == -EAGAIN)
+ schedule_timeout_interruptible(msecs_to_jiffies
+ (GC_SLEEP_MS));
+ else if (ret)
+ pr_warn("gc failed!");
+ } while (ret && !test_bit(CACHE_SET_IO_DISABLE, &c->flags));
+
+ bch_btree_gc_finish(c);
+ wake_up_allocators(c);
+
+ bch_time_stats_update(&c->btree_gc_time, start_time);
+
+ stats.key_bytes *= sizeof(uint64_t);
+ stats.data <<= 9;
+ bch_update_bucket_in_use(c, &stats);
+ memcpy(&c->gc_stats, &stats, sizeof(struct gc_stat));
+
+ trace_bcache_gc_end(c);
+
+ bch_moving_gc(c);
+}
+
+static bool gc_should_run(struct cache_set *c)
+{
+ struct cache *ca;
+ unsigned int i;
+
+ for_each_cache(ca, c, i)
+ if (ca->invalidate_needs_gc)
+ return true;
+
+ if (atomic_read(&c->sectors_to_gc) < 0)
+ return true;
+
+ return false;
+}
+
+static int bch_gc_thread(void *arg)
+{
+ struct cache_set *c = arg;
+
+ while (1) {
+ wait_event_interruptible(c->gc_wait,
+ kthread_should_stop() ||
+ test_bit(CACHE_SET_IO_DISABLE, &c->flags) ||
+ gc_should_run(c));
+
+ if (kthread_should_stop() ||
+ test_bit(CACHE_SET_IO_DISABLE, &c->flags))
+ break;
+
+ set_gc_sectors(c);
+ bch_btree_gc(c);
+ }
+
+ wait_for_kthread_stop();
+ return 0;
+}
+
+int bch_gc_thread_start(struct cache_set *c)
+{
+ c->gc_thread = kthread_run(bch_gc_thread, c, "bcache_gc");
+ return PTR_ERR_OR_ZERO(c->gc_thread);
+}
+
+/* Initial partial gc */
+
+static int bch_btree_check_recurse(struct btree *b, struct btree_op *op)
+{
+ int ret = 0;
+ struct bkey *k, *p = NULL;
+ struct btree_iter iter;
+
+ for_each_key_filter(&b->keys, k, &iter, bch_ptr_invalid)
+ bch_initial_mark_key(b->c, b->level, k);
+
+ bch_initial_mark_key(b->c, b->level + 1, &b->key);
+
+ if (b->level) {
+ bch_btree_iter_init(&b->keys, &iter, NULL);
+
+ do {
+ k = bch_btree_iter_next_filter(&iter, &b->keys,
+ bch_ptr_bad);
+ if (k) {
+ btree_node_prefetch(b, k);
+ /*
+ * initiallize c->gc_stats.nodes
+ * for incremental GC
+ */
+ b->c->gc_stats.nodes++;
+ }
+
+ if (p)
+ ret = btree(check_recurse, p, b, op);
+
+ p = k;
+ } while (p && !ret);
+ }
+
+ return ret;
+}
+
+int bch_btree_check(struct cache_set *c)
+{
+ struct btree_op op;
+
+ bch_btree_op_init(&op, SHRT_MAX);
+
+ return btree_root(check_recurse, c, &op);
+}
+
+void bch_initial_gc_finish(struct cache_set *c)
+{
+ struct cache *ca;
+ struct bucket *b;
+ unsigned int i;
+
+ bch_btree_gc_finish(c);
+
+ mutex_lock(&c->bucket_lock);
+
+ /*
+ * We need to put some unused buckets directly on the prio freelist in
+ * order to get the allocator thread started - it needs freed buckets in
+ * order to rewrite the prios and gens, and it needs to rewrite prios
+ * and gens in order to free buckets.
+ *
+ * This is only safe for buckets that have no live data in them, which
+ * there should always be some of.
+ */
+ for_each_cache(ca, c, i) {
+ for_each_bucket(b, ca) {
+ if (fifo_full(&ca->free[RESERVE_PRIO]) &&
+ fifo_full(&ca->free[RESERVE_BTREE]))
+ break;
+
+ if (bch_can_invalidate_bucket(ca, b) &&
+ !GC_MARK(b)) {
+ __bch_invalidate_one_bucket(ca, b);
+ if (!fifo_push(&ca->free[RESERVE_PRIO],
+ b - ca->buckets))
+ fifo_push(&ca->free[RESERVE_BTREE],
+ b - ca->buckets);
+ }
+ }
+ }
+
+ mutex_unlock(&c->bucket_lock);
+}
+
+/* Btree insertion */
+
+static bool btree_insert_key(struct btree *b, struct bkey *k,
+ struct bkey *replace_key)
+{
+ unsigned int status;
+
+ BUG_ON(bkey_cmp(k, &b->key) > 0);
+
+ status = bch_btree_insert_key(&b->keys, k, replace_key);
+ if (status != BTREE_INSERT_STATUS_NO_INSERT) {
+ bch_check_keys(&b->keys, "%u for %s", status,
+ replace_key ? "replace" : "insert");
+
+ trace_bcache_btree_insert_key(b, k, replace_key != NULL,
+ status);
+ return true;
+ } else
+ return false;
+}
+
+static size_t insert_u64s_remaining(struct btree *b)
+{
+ long ret = bch_btree_keys_u64s_remaining(&b->keys);
+
+ /*
+ * Might land in the middle of an existing extent and have to split it
+ */
+ if (b->keys.ops->is_extents)
+ ret -= KEY_MAX_U64S;
+
+ return max(ret, 0L);
+}
+
+static bool bch_btree_insert_keys(struct btree *b, struct btree_op *op,
+ struct keylist *insert_keys,
+ struct bkey *replace_key)
+{
+ bool ret = false;
+ int oldsize = bch_count_data(&b->keys);
+
+ while (!bch_keylist_empty(insert_keys)) {
+ struct bkey *k = insert_keys->keys;
+
+ if (bkey_u64s(k) > insert_u64s_remaining(b))
+ break;
+
+ if (bkey_cmp(k, &b->key) <= 0) {
+ if (!b->level)
+ bkey_put(b->c, k);
+
+ ret |= btree_insert_key(b, k, replace_key);
+ bch_keylist_pop_front(insert_keys);
+ } else if (bkey_cmp(&START_KEY(k), &b->key) < 0) {
+ BKEY_PADDED(key) temp;
+ bkey_copy(&temp.key, insert_keys->keys);
+
+ bch_cut_back(&b->key, &temp.key);
+ bch_cut_front(&b->key, insert_keys->keys);
+
+ ret |= btree_insert_key(b, &temp.key, replace_key);
+ break;
+ } else {
+ break;
+ }
+ }
+
+ if (!ret)
+ op->insert_collision = true;
+
+ BUG_ON(!bch_keylist_empty(insert_keys) && b->level);
+
+ BUG_ON(bch_count_data(&b->keys) < oldsize);
+ return ret;
+}
+
+static int btree_split(struct btree *b, struct btree_op *op,
+ struct keylist *insert_keys,
+ struct bkey *replace_key)
+{
+ bool split;
+ struct btree *n1, *n2 = NULL, *n3 = NULL;
+ uint64_t start_time = local_clock();
+ struct closure cl;
+ struct keylist parent_keys;
+
+ closure_init_stack(&cl);
+ bch_keylist_init(&parent_keys);
+
+ if (btree_check_reserve(b, op)) {
+ if (!b->level)
+ return -EINTR;
+ else
+ WARN(1, "insufficient reserve for split\n");
+ }
+
+ n1 = btree_node_alloc_replacement(b, op);
+ if (IS_ERR(n1))
+ goto err;
+
+ split = set_blocks(btree_bset_first(n1),
+ block_bytes(n1->c)) > (btree_blocks(b) * 4) / 5;
+
+ if (split) {
+ unsigned int keys = 0;
+
+ trace_bcache_btree_node_split(b, btree_bset_first(n1)->keys);
+
+ n2 = bch_btree_node_alloc(b->c, op, b->level, b->parent);
+ if (IS_ERR(n2))
+ goto err_free1;
+
+ if (!b->parent) {
+ n3 = bch_btree_node_alloc(b->c, op, b->level + 1, NULL);
+ if (IS_ERR(n3))
+ goto err_free2;
+ }
+
+ mutex_lock(&n1->write_lock);
+ mutex_lock(&n2->write_lock);
+
+ bch_btree_insert_keys(n1, op, insert_keys, replace_key);
+
+ /*
+ * Has to be a linear search because we don't have an auxiliary
+ * search tree yet
+ */
+
+ while (keys < (btree_bset_first(n1)->keys * 3) / 5)
+ keys += bkey_u64s(bset_bkey_idx(btree_bset_first(n1),
+ keys));
+
+ bkey_copy_key(&n1->key,
+ bset_bkey_idx(btree_bset_first(n1), keys));
+ keys += bkey_u64s(bset_bkey_idx(btree_bset_first(n1), keys));
+
+ btree_bset_first(n2)->keys = btree_bset_first(n1)->keys - keys;
+ btree_bset_first(n1)->keys = keys;
+
+ memcpy(btree_bset_first(n2)->start,
+ bset_bkey_last(btree_bset_first(n1)),
+ btree_bset_first(n2)->keys * sizeof(uint64_t));
+
+ bkey_copy_key(&n2->key, &b->key);
+
+ bch_keylist_add(&parent_keys, &n2->key);
+ bch_btree_node_write(n2, &cl);
+ mutex_unlock(&n2->write_lock);
+ rw_unlock(true, n2);
+ } else {
+ trace_bcache_btree_node_compact(b, btree_bset_first(n1)->keys);
+
+ mutex_lock(&n1->write_lock);
+ bch_btree_insert_keys(n1, op, insert_keys, replace_key);
+ }
+
+ bch_keylist_add(&parent_keys, &n1->key);
+ bch_btree_node_write(n1, &cl);
+ mutex_unlock(&n1->write_lock);
+
+ if (n3) {
+ /* Depth increases, make a new root */
+ mutex_lock(&n3->write_lock);
+ bkey_copy_key(&n3->key, &MAX_KEY);
+ bch_btree_insert_keys(n3, op, &parent_keys, NULL);
+ bch_btree_node_write(n3, &cl);
+ mutex_unlock(&n3->write_lock);
+
+ closure_sync(&cl);
+ bch_btree_set_root(n3);
+ rw_unlock(true, n3);
+ } else if (!b->parent) {
+ /* Root filled up but didn't need to be split */
+ closure_sync(&cl);
+ bch_btree_set_root(n1);
+ } else {
+ /* Split a non root node */
+ closure_sync(&cl);
+ make_btree_freeing_key(b, parent_keys.top);
+ bch_keylist_push(&parent_keys);
+
+ bch_btree_insert_node(b->parent, op, &parent_keys, NULL, NULL);
+ BUG_ON(!bch_keylist_empty(&parent_keys));
+ }
+
+ btree_node_free(b);
+ rw_unlock(true, n1);
+
+ bch_time_stats_update(&b->c->btree_split_time, start_time);
+
+ return 0;
+err_free2:
+ bkey_put(b->c, &n2->key);
+ btree_node_free(n2);
+ rw_unlock(true, n2);
+err_free1:
+ bkey_put(b->c, &n1->key);
+ btree_node_free(n1);
+ rw_unlock(true, n1);
+err:
+ WARN(1, "bcache: btree split failed (level %u)", b->level);
+
+ if (n3 == ERR_PTR(-EAGAIN) ||
+ n2 == ERR_PTR(-EAGAIN) ||
+ n1 == ERR_PTR(-EAGAIN))
+ return -EAGAIN;
+
+ return -ENOMEM;
+}
+
+static int bch_btree_insert_node(struct btree *b, struct btree_op *op,
+ struct keylist *insert_keys,
+ atomic_t *journal_ref,
+ struct bkey *replace_key)
+{
+ struct closure cl;
+
+ BUG_ON(b->level && replace_key);
+
+ closure_init_stack(&cl);
+
+ mutex_lock(&b->write_lock);
+
+ if (write_block(b) != btree_bset_last(b) &&
+ b->keys.last_set_unwritten)
+ bch_btree_init_next(b); /* just wrote a set */
+
+ if (bch_keylist_nkeys(insert_keys) > insert_u64s_remaining(b)) {
+ mutex_unlock(&b->write_lock);
+ goto split;
+ }
+
+ BUG_ON(write_block(b) != btree_bset_last(b));
+
+ if (bch_btree_insert_keys(b, op, insert_keys, replace_key)) {
+ if (!b->level)
+ bch_btree_leaf_dirty(b, journal_ref);
+ else
+ bch_btree_node_write(b, &cl);
+ }
+
+ mutex_unlock(&b->write_lock);
+
+ /* wait for btree node write if necessary, after unlock */
+ closure_sync(&cl);
+
+ return 0;
+split:
+ if (current->bio_list) {
+ op->lock = b->c->root->level + 1;
+ return -EAGAIN;
+ } else if (op->lock <= b->c->root->level) {
+ op->lock = b->c->root->level + 1;
+ return -EINTR;
+ } else {
+ /* Invalidated all iterators */
+ int ret = btree_split(b, op, insert_keys, replace_key);
+
+ if (bch_keylist_empty(insert_keys))
+ return 0;
+ else if (!ret)
+ return -EINTR;
+ return ret;
+ }
+}
+
+int bch_btree_insert_check_key(struct btree *b, struct btree_op *op,
+ struct bkey *check_key)
+{
+ int ret = -EINTR;
+ uint64_t btree_ptr = b->key.ptr[0];
+ unsigned long seq = b->seq;
+ struct keylist insert;
+ bool upgrade = op->lock == -1;
+
+ bch_keylist_init(&insert);
+
+ if (upgrade) {
+ rw_unlock(false, b);
+ rw_lock(true, b, b->level);
+
+ if (b->key.ptr[0] != btree_ptr ||
+ b->seq != seq + 1) {
+ op->lock = b->level;
+ goto out;
+ }
+ }
+
+ SET_KEY_PTRS(check_key, 1);
+ get_random_bytes(&check_key->ptr[0], sizeof(uint64_t));
+
+ SET_PTR_DEV(check_key, 0, PTR_CHECK_DEV);
+
+ bch_keylist_add(&insert, check_key);
+
+ ret = bch_btree_insert_node(b, op, &insert, NULL, NULL);
+
+ BUG_ON(!ret && !bch_keylist_empty(&insert));
+out:
+ if (upgrade)
+ downgrade_write(&b->lock);
+ return ret;
+}
+
+struct btree_insert_op {
+ struct btree_op op;
+ struct keylist *keys;
+ atomic_t *journal_ref;
+ struct bkey *replace_key;
+};
+
+static int btree_insert_fn(struct btree_op *b_op, struct btree *b)
+{
+ struct btree_insert_op *op = container_of(b_op,
+ struct btree_insert_op, op);
+
+ int ret = bch_btree_insert_node(b, &op->op, op->keys,
+ op->journal_ref, op->replace_key);
+ if (ret && !bch_keylist_empty(op->keys))
+ return ret;
+ else
+ return MAP_DONE;
+}
+
+int bch_btree_insert(struct cache_set *c, struct keylist *keys,
+ atomic_t *journal_ref, struct bkey *replace_key)
+{
+ struct btree_insert_op op;
+ int ret = 0;
+
+ BUG_ON(current->bio_list);
+ BUG_ON(bch_keylist_empty(keys));
+
+ bch_btree_op_init(&op.op, 0);
+ op.keys = keys;
+ op.journal_ref = journal_ref;
+ op.replace_key = replace_key;
+
+ while (!ret && !bch_keylist_empty(keys)) {
+ op.op.lock = 0;
+ ret = bch_btree_map_leaf_nodes(&op.op, c,
+ &START_KEY(keys->keys),
+ btree_insert_fn);
+ }
+
+ if (ret) {
+ struct bkey *k;
+
+ pr_err("error %i", ret);
+
+ while ((k = bch_keylist_pop(keys)))
+ bkey_put(c, k);
+ } else if (op.op.insert_collision)
+ ret = -ESRCH;
+
+ return ret;
+}
+
+void bch_btree_set_root(struct btree *b)
+{
+ unsigned int i;
+ struct closure cl;
+
+ closure_init_stack(&cl);
+
+ trace_bcache_btree_set_root(b);
+
+ BUG_ON(!b->written);
+
+ for (i = 0; i < KEY_PTRS(&b->key); i++)
+ BUG_ON(PTR_BUCKET(b->c, &b->key, i)->prio != BTREE_PRIO);
+
+ mutex_lock(&b->c->bucket_lock);
+ list_del_init(&b->list);
+ mutex_unlock(&b->c->bucket_lock);
+
+ b->c->root = b;
+
+ bch_journal_meta(b->c, &cl);
+ closure_sync(&cl);
+}
+
+/* Map across nodes or keys */
+
+static int bch_btree_map_nodes_recurse(struct btree *b, struct btree_op *op,
+ struct bkey *from,
+ btree_map_nodes_fn *fn, int flags)
+{
+ int ret = MAP_CONTINUE;
+
+ if (b->level) {
+ struct bkey *k;
+ struct btree_iter iter;
+
+ bch_btree_iter_init(&b->keys, &iter, from);
+
+ while ((k = bch_btree_iter_next_filter(&iter, &b->keys,
+ bch_ptr_bad))) {
+ ret = btree(map_nodes_recurse, k, b,
+ op, from, fn, flags);
+ from = NULL;
+
+ if (ret != MAP_CONTINUE)
+ return ret;
+ }
+ }
+
+ if (!b->level || flags == MAP_ALL_NODES)
+ ret = fn(op, b);
+
+ return ret;
+}
+
+int __bch_btree_map_nodes(struct btree_op *op, struct cache_set *c,
+ struct bkey *from, btree_map_nodes_fn *fn, int flags)
+{
+ return btree_root(map_nodes_recurse, c, op, from, fn, flags);
+}
+
+static int bch_btree_map_keys_recurse(struct btree *b, struct btree_op *op,
+ struct bkey *from, btree_map_keys_fn *fn,
+ int flags)
+{
+ int ret = MAP_CONTINUE;
+ struct bkey *k;
+ struct btree_iter iter;
+
+ bch_btree_iter_init(&b->keys, &iter, from);
+
+ while ((k = bch_btree_iter_next_filter(&iter, &b->keys, bch_ptr_bad))) {
+ ret = !b->level
+ ? fn(op, b, k)
+ : btree(map_keys_recurse, k, b, op, from, fn, flags);
+ from = NULL;
+
+ if (ret != MAP_CONTINUE)
+ return ret;
+ }
+
+ if (!b->level && (flags & MAP_END_KEY))
+ ret = fn(op, b, &KEY(KEY_INODE(&b->key),
+ KEY_OFFSET(&b->key), 0));
+
+ return ret;
+}
+
+int bch_btree_map_keys(struct btree_op *op, struct cache_set *c,
+ struct bkey *from, btree_map_keys_fn *fn, int flags)
+{
+ return btree_root(map_keys_recurse, c, op, from, fn, flags);
+}
+
+/* Keybuf code */
+
+static inline int keybuf_cmp(struct keybuf_key *l, struct keybuf_key *r)
+{
+ /* Overlapping keys compare equal */
+ if (bkey_cmp(&l->key, &START_KEY(&r->key)) <= 0)
+ return -1;
+ if (bkey_cmp(&START_KEY(&l->key), &r->key) >= 0)
+ return 1;
+ return 0;
+}
+
+static inline int keybuf_nonoverlapping_cmp(struct keybuf_key *l,
+ struct keybuf_key *r)
+{
+ return clamp_t(int64_t, bkey_cmp(&l->key, &r->key), -1, 1);
+}
+
+struct refill {
+ struct btree_op op;
+ unsigned int nr_found;
+ struct keybuf *buf;
+ struct bkey *end;
+ keybuf_pred_fn *pred;
+};
+
+static int refill_keybuf_fn(struct btree_op *op, struct btree *b,
+ struct bkey *k)
+{
+ struct refill *refill = container_of(op, struct refill, op);
+ struct keybuf *buf = refill->buf;
+ int ret = MAP_CONTINUE;
+
+ if (bkey_cmp(k, refill->end) > 0) {
+ ret = MAP_DONE;
+ goto out;
+ }
+
+ if (!KEY_SIZE(k)) /* end key */
+ goto out;
+
+ if (refill->pred(buf, k)) {
+ struct keybuf_key *w;
+
+ spin_lock(&buf->lock);
+
+ w = array_alloc(&buf->freelist);
+ if (!w) {
+ spin_unlock(&buf->lock);
+ return MAP_DONE;
+ }
+
+ w->private = NULL;
+ bkey_copy(&w->key, k);
+
+ if (RB_INSERT(&buf->keys, w, node, keybuf_cmp))
+ array_free(&buf->freelist, w);
+ else
+ refill->nr_found++;
+
+ if (array_freelist_empty(&buf->freelist))
+ ret = MAP_DONE;
+
+ spin_unlock(&buf->lock);
+ }
+out:
+ buf->last_scanned = *k;
+ return ret;
+}
+
+void bch_refill_keybuf(struct cache_set *c, struct keybuf *buf,
+ struct bkey *end, keybuf_pred_fn *pred)
+{
+ struct bkey start = buf->last_scanned;
+ struct refill refill;
+
+ cond_resched();
+
+ bch_btree_op_init(&refill.op, -1);
+ refill.nr_found = 0;
+ refill.buf = buf;
+ refill.end = end;
+ refill.pred = pred;
+
+ bch_btree_map_keys(&refill.op, c, &buf->last_scanned,
+ refill_keybuf_fn, MAP_END_KEY);
+
+ trace_bcache_keyscan(refill.nr_found,
+ KEY_INODE(&start), KEY_OFFSET(&start),
+ KEY_INODE(&buf->last_scanned),
+ KEY_OFFSET(&buf->last_scanned));
+
+ spin_lock(&buf->lock);
+
+ if (!RB_EMPTY_ROOT(&buf->keys)) {
+ struct keybuf_key *w;
+
+ w = RB_FIRST(&buf->keys, struct keybuf_key, node);
+ buf->start = START_KEY(&w->key);
+
+ w = RB_LAST(&buf->keys, struct keybuf_key, node);
+ buf->end = w->key;
+ } else {
+ buf->start = MAX_KEY;
+ buf->end = MAX_KEY;
+ }
+
+ spin_unlock(&buf->lock);
+}
+
+static void __bch_keybuf_del(struct keybuf *buf, struct keybuf_key *w)
+{
+ rb_erase(&w->node, &buf->keys);
+ array_free(&buf->freelist, w);
+}
+
+void bch_keybuf_del(struct keybuf *buf, struct keybuf_key *w)
+{
+ spin_lock(&buf->lock);
+ __bch_keybuf_del(buf, w);
+ spin_unlock(&buf->lock);
+}
+
+bool bch_keybuf_check_overlapping(struct keybuf *buf, struct bkey *start,
+ struct bkey *end)
+{
+ bool ret = false;
+ struct keybuf_key *p, *w, s;
+
+ s.key = *start;
+
+ if (bkey_cmp(end, &buf->start) <= 0 ||
+ bkey_cmp(start, &buf->end) >= 0)
+ return false;
+
+ spin_lock(&buf->lock);
+ w = RB_GREATER(&buf->keys, s, node, keybuf_nonoverlapping_cmp);
+
+ while (w && bkey_cmp(&START_KEY(&w->key), end) < 0) {
+ p = w;
+ w = RB_NEXT(w, node);
+
+ if (p->private)
+ ret = true;
+ else
+ __bch_keybuf_del(buf, p);
+ }
+
+ spin_unlock(&buf->lock);
+ return ret;
+}
+
+struct keybuf_key *bch_keybuf_next(struct keybuf *buf)
+{
+ struct keybuf_key *w;
+
+ spin_lock(&buf->lock);
+
+ w = RB_FIRST(&buf->keys, struct keybuf_key, node);
+
+ while (w && w->private)
+ w = RB_NEXT(w, node);
+
+ if (w)
+ w->private = ERR_PTR(-EINTR);
+
+ spin_unlock(&buf->lock);
+ return w;
+}
+
+struct keybuf_key *bch_keybuf_next_rescan(struct cache_set *c,
+ struct keybuf *buf,
+ struct bkey *end,
+ keybuf_pred_fn *pred)
+{
+ struct keybuf_key *ret;
+
+ while (1) {
+ ret = bch_keybuf_next(buf);
+ if (ret)
+ break;
+
+ if (bkey_cmp(&buf->last_scanned, end) >= 0) {
+ pr_debug("scan finished");
+ break;
+ }
+
+ bch_refill_keybuf(c, buf, end, pred);
+ }
+
+ return ret;
+}
+
+void bch_keybuf_init(struct keybuf *buf)
+{
+ buf->last_scanned = MAX_KEY;
+ buf->keys = RB_ROOT;
+
+ spin_lock_init(&buf->lock);
+ array_allocator_init(&buf->freelist);
+}