1 files changed, 252 insertions, 0 deletions
diff --git a/drivers/md/bcache/movinggc.c b/drivers/md/bcache/movinggc.c
new file mode 100644
index 000000000..99499d1f6
--- /dev/null
+++ b/drivers/md/bcache/movinggc.c
@@ -0,0 +1,252 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Moving/copying garbage collector
+ *
+ * Copyright 2012 Google, Inc.
+ */
+
+#include "bcache.h"
+#include "btree.h"
+#include "debug.h"
+#include "request.h"
+
+#include <trace/events/bcache.h>
+
+struct moving_io {
+	struct closure		cl;
+	struct keybuf_key	*w;
+	struct data_insert_op	op;
+	struct bbio		bio;
+};
+
+static bool moving_pred(struct keybuf *buf, struct bkey *k)
+{
+	struct cache_set *c = container_of(buf, struct cache_set,
+					   moving_gc_keys);
+	unsigned int i;
+
+	for (i = 0; i < KEY_PTRS(k); i++)
+		if (ptr_available(c, k, i) &&
+		    GC_MOVE(PTR_BUCKET(c, k, i)))
+			return true;
+
+	return false;
+}
+
+/* Moving GC - IO loop */
+
+static void moving_io_destructor(struct closure *cl)
+{
+	struct moving_io *io = container_of(cl, struct moving_io, cl);
+
+	kfree(io);
+}
+
+static void write_moving_finish(struct closure *cl)
+{
+	struct moving_io *io = container_of(cl, struct moving_io, cl);
+	struct bio *bio = &io->bio.bio;
+
+	bio_free_pages(bio);
+
+	if (io->op.replace_collision)
+		trace_bcache_gc_copy_collision(&io->w->key);
+
+	bch_keybuf_del(&io->op.c->moving_gc_keys, io->w);
+
+	up(&io->op.c->moving_in_flight);
+
+	closure_return_with_destructor(cl, moving_io_destructor);
+}
+
+static void read_moving_endio(struct bio *bio)
+{
+	struct bbio *b = container_of(bio, struct bbio, bio);
+	struct moving_io *io = container_of(bio->bi_private,
+					    struct moving_io, cl);
+
+	if (bio->bi_status)
+		io->op.status = bio->bi_status;
+	else if (!KEY_DIRTY(&b->key) &&
+		 ptr_stale(io->op.c, &b->key, 0)) {
+		io->op.status = BLK_STS_IOERR;
+	}
+
+	bch_bbio_endio(io->op.c, bio, bio->bi_status, "reading data to move");
+}
+
+static void moving_init(struct moving_io *io)
+{
+	struct bio *bio = &io->bio.bio;
+
+	bio_init(bio, NULL, bio->bi_inline_vecs,
+		 DIV_ROUND_UP(KEY_SIZE(&io->w->key), PAGE_SECTORS), 0);
+	bio_get(bio);
+	bio_set_prio(bio, IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0));
+
+	bio->bi_iter.bi_size	= KEY_SIZE(&io->w->key) << 9;
+	bio->bi_private		= &io->cl;
+	bch_bio_map(bio, NULL);
+}
+
+static void write_moving(struct closure *cl)
+{
+	struct moving_io *io = container_of(cl, struct moving_io, cl);
+	struct data_insert_op *op = &io->op;
+
+	if (!op->status) {
+		moving_init(io);
+
+		io->bio.bio.bi_iter.bi_sector = KEY_START(&io->w->key);
+		op->write_prio		= 1;
+		op->bio			= &io->bio.bio;
+
+		op->writeback		= KEY_DIRTY(&io->w->key);
+		op->csum		= KEY_CSUM(&io->w->key);
+
+		bkey_copy(&op->replace_key, &io->w->key);
+		op->replace		= true;
+
+		closure_call(&op->cl, bch_data_insert, NULL, cl);
+	}
+
+	continue_at(cl, write_moving_finish, op->wq);
+}
+
+static void read_moving_submit(struct closure *cl)
+{
+	struct moving_io *io = container_of(cl, struct moving_io, cl);
+	struct bio *bio = &io->bio.bio;
+
+	bch_submit_bbio(bio, io->op.c, &io->w->key, 0);
+
+	continue_at(cl, write_moving, io->op.wq);
+}
+
+static void read_moving(struct cache_set *c)
+{
+	struct keybuf_key *w;
+	struct moving_io *io;
+	struct bio *bio;
+	struct closure cl;
+
+	closure_init_stack(&cl);
+
+	/* XXX: if we error, background writeback could stall indefinitely */
+
+	while (!test_bit(CACHE_SET_STOPPING, &c->flags)) {
+		w = bch_keybuf_next_rescan(c, &c->moving_gc_keys,
+					   &MAX_KEY, moving_pred);
+		if (!w)
+			break;
+
+		if (ptr_stale(c, &w->key, 0)) {
+			bch_keybuf_del(&c->moving_gc_keys, w);
+			continue;
+		}
+
+		io = kzalloc(struct_size(io, bio.bio.bi_inline_vecs,
+					 DIV_ROUND_UP(KEY_SIZE(&w->key), PAGE_SECTORS)),
+			     GFP_KERNEL);
+		if (!io)
+			goto err;
+
+		w->private	= io;
+		io->w		= w;
+		io->op.inode	= KEY_INODE(&w->key);
+		io->op.c	= c;
+		io->op.wq	= c->moving_gc_wq;
+
+		moving_init(io);
+		bio = &io->bio.bio;
+
+		bio_set_op_attrs(bio, REQ_OP_READ, 0);
+		bio->bi_end_io	= read_moving_endio;
+
+		if (bch_bio_alloc_pages(bio, GFP_KERNEL))
+			goto err;
+
+		trace_bcache_gc_copy(&w->key);
+
+		down(&c->moving_in_flight);
+		closure_call(&io->cl, read_moving_submit, NULL, &cl);
+	}
+
+	if (0) {
+err:		if (!IS_ERR_OR_NULL(w->private))
+			kfree(w->private);
+
+		bch_keybuf_del(&c->moving_gc_keys, w);
+	}
+
+	closure_sync(&cl);
+}
+
+static bool bucket_cmp(struct bucket *l, struct bucket *r)
+{
+	return GC_SECTORS_USED(l) < GC_SECTORS_USED(r);
+}
+
+static unsigned int bucket_heap_top(struct cache *ca)
+{
+	struct bucket *b;
+
+	return (b = heap_peek(&ca->heap)) ? GC_SECTORS_USED(b) : 0;
+}
+
+void bch_moving_gc(struct cache_set *c)
+{
+	struct cache *ca = c->cache;
+	struct bucket *b;
+	unsigned long sectors_to_move, reserve_sectors;
+
+	if (!c->copy_gc_enabled)
+		return;
+
+	mutex_lock(&c->bucket_lock);
+
+	sectors_to_move = 0;
+	reserve_sectors = ca->sb.bucket_size *
+			     fifo_used(&ca->free[RESERVE_MOVINGGC]);
+
+	ca->heap.used = 0;
+
+	for_each_bucket(b, ca) {
+		if (GC_MARK(b) == GC_MARK_METADATA ||
+		    !GC_SECTORS_USED(b) ||
+		    GC_SECTORS_USED(b) == ca->sb.bucket_size ||
+		    atomic_read(&b->pin))
+			continue;
+
+		if (!heap_full(&ca->heap)) {
+			sectors_to_move += GC_SECTORS_USED(b);
+			heap_add(&ca->heap, b, bucket_cmp);
+		} else if (bucket_cmp(b, heap_peek(&ca->heap))) {
+			sectors_to_move -= bucket_heap_top(ca);
+			sectors_to_move += GC_SECTORS_USED(b);
+
+			ca->heap.data[0] = b;
+			heap_sift(&ca->heap, 0, bucket_cmp);
+		}
+	}
+
+	while (sectors_to_move > reserve_sectors) {
+		heap_pop(&ca->heap, b, bucket_cmp);
+		sectors_to_move -= GC_SECTORS_USED(b);
+	}
+
+	while (heap_pop(&ca->heap, b, bucket_cmp))
+		SET_GC_MOVE(b, 1);
+
+	mutex_unlock(&c->bucket_lock);
+
+	c->moving_gc_keys.last_scanned = ZERO_KEY;
+
+	read_moving(c);
+}
+
+void bch_moving_init_cache_set(struct cache_set *c)
+{
+	bch_keybuf_init(&c->moving_gc_keys);
+	sema_init(&c->moving_in_flight, 64);
+}