#ifndef _BCACHE_WRITEBACK_H
#define _BCACHE_WRITEBACK_H

#include "blockdev.h"
#include "buckets.h"

#define CUTOFF_WRITEBACK	60
#define CUTOFF_WRITEBACK_SYNC	30

static inline uint64_t bcache_dev_sectors_dirty(struct bcache_device *d)
{
	uint64_t i, ret = 0;

	for (i = 0; i < d->nr_stripes; i++)
		ret += atomic_read(d->stripe_sectors_dirty + i);

	return ret;
}

static inline unsigned offset_to_stripe(struct bcache_device *d,
					uint64_t offset)
{
	do_div(offset, d->stripe_size);
	return offset;
}

static inline bool bcache_dev_stripe_dirty(struct cached_dev *dc,
					   uint64_t offset,
					   unsigned nr_sectors)
{
	unsigned stripe = offset_to_stripe(&dc->disk, offset);

	while (1) {
		if (atomic_read(dc->disk.stripe_sectors_dirty + stripe))
			return true;

		if (nr_sectors <= dc->disk.stripe_size)
			return false;

		nr_sectors -= dc->disk.stripe_size;
		stripe++;
	}
}

static inline bool should_writeback(struct cached_dev *dc, struct bio *bio,
				    unsigned cache_mode, bool would_skip)
{
	struct bch_fs *c = dc->disk.c;
	u64 available = sectors_available(c);

	if (cache_mode != CACHE_MODE_WRITEBACK ||
	    test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) ||
	    available * 100 < c->capacity * CUTOFF_WRITEBACK_SYNC)
		return false;

	if (dc->partial_stripes_expensive &&
	    bcache_dev_stripe_dirty(dc, bio->bi_iter.bi_sector,
				    bio_sectors(bio)))
		return true;

	if (would_skip)
		return false;

	return bio->bi_opf & REQ_SYNC ||
		available * 100 < c->capacity * CUTOFF_WRITEBACK;
}

static inline void bch_writeback_queue(struct cached_dev *dc)
{
	if (!IS_ERR_OR_NULL(dc->writeback_thread))
		wake_up_process(dc->writeback_thread);
}

static inline void bch_writeback_add(struct cached_dev *dc)
{
	if (!atomic_read(&dc->has_dirty) &&
	    !atomic_xchg(&dc->has_dirty, 1)) {
		atomic_inc(&dc->count);

		if (BDEV_STATE(dc->disk_sb.sb) != BDEV_STATE_DIRTY) {
			SET_BDEV_STATE(dc->disk_sb.sb, BDEV_STATE_DIRTY);
			/* XXX: should do this synchronously */
			bch_write_bdev_super(dc, NULL);
		}

		bch_writeback_queue(dc);
	}
}

#ifndef NO_BCACHE_WRITEBACK

void bcache_dev_sectors_dirty_add(struct bch_fs *, unsigned, u64, int);

void bch_writeback_recalc_oldest_gens(struct bch_fs *);
void bch_sectors_dirty_init(struct cached_dev *, struct bch_fs *c);

void bch_cached_dev_writeback_stop(struct cached_dev *);
void bch_cached_dev_writeback_free(struct cached_dev *);
int bch_cached_dev_writeback_init(struct cached_dev *);
int bch_cached_dev_writeback_start(struct cached_dev *);

#else

static inline void bcache_dev_sectors_dirty_add(struct bch_fs *c,
						unsigned i, u64 o, int n) {}
static inline void bch_writeback_recalc_oldest_gens(struct bch_fs *c) {}
static inline void bch_sectors_dirty_init(struct cached_dev *dc,
					  struct bch_fs *c) {}
static inline void bch_cached_dev_writeback_stop(struct cached_dev *dc) {}
static inline void bch_cached_dev_writeback_free(struct cached_dev *dc) {}
static inline int bch_cached_dev_writeback_init(struct cached_dev *dc)
{
	return 0;
}
static inline int bch_cached_dev_writeback_start(struct cached_dev *dc)
{
	return 0;
}

#endif

#endif