1#ifndef _BCACHE_WRITEBACK_H
2#define _BCACHE_WRITEBACK_H
3
4#define CUTOFF_WRITEBACK	40
5#define CUTOFF_WRITEBACK_SYNC	70
6
7static inline uint64_t bcache_dev_sectors_dirty(struct bcache_device *d)
8{
9	uint64_t i, ret = 0;
10
11	for (i = 0; i < d->nr_stripes; i++)
12		ret += atomic_read(d->stripe_sectors_dirty + i);
13
14	return ret;
15}
16
17static inline unsigned offset_to_stripe(struct bcache_device *d,
18					uint64_t offset)
19{
20	do_div(offset, d->stripe_size);
21	return offset;
22}
23
24static inline bool bcache_dev_stripe_dirty(struct cached_dev *dc,
25					   uint64_t offset,
26					   unsigned nr_sectors)
27{
28	unsigned stripe = offset_to_stripe(&dc->disk, offset);
29
30	while (1) {
31		if (atomic_read(dc->disk.stripe_sectors_dirty + stripe))
32			return true;
33
34		if (nr_sectors <= dc->disk.stripe_size)
35			return false;
36
37		nr_sectors -= dc->disk.stripe_size;
38		stripe++;
39	}
40}
41
42static inline bool should_writeback(struct cached_dev *dc, struct bio *bio,
43				    unsigned cache_mode, bool would_skip)
44{
45	unsigned in_use = dc->disk.c->gc_stats.in_use;
46
47	if (cache_mode != CACHE_MODE_WRITEBACK ||
48	    test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) ||
49	    in_use > CUTOFF_WRITEBACK_SYNC)
50		return false;
51
52	if (dc->partial_stripes_expensive &&
53	    bcache_dev_stripe_dirty(dc, bio->bi_iter.bi_sector,
54				    bio_sectors(bio)))
55		return true;
56
57	if (would_skip)
58		return false;
59
60	return bio->bi_rw & REQ_SYNC ||
61		in_use <= CUTOFF_WRITEBACK;
62}
63
64static inline void bch_writeback_queue(struct cached_dev *dc)
65{
66	if (!IS_ERR_OR_NULL(dc->writeback_thread))
67		wake_up_process(dc->writeback_thread);
68}
69
70static inline void bch_writeback_add(struct cached_dev *dc)
71{
72	if (!atomic_read(&dc->has_dirty) &&
73	    !atomic_xchg(&dc->has_dirty, 1)) {
74		atomic_inc(&dc->count);
75
76		if (BDEV_STATE(&dc->sb) != BDEV_STATE_DIRTY) {
77			SET_BDEV_STATE(&dc->sb, BDEV_STATE_DIRTY);
78			/* XXX: should do this synchronously */
79			bch_write_bdev_super(dc, NULL);
80		}
81
82		bch_writeback_queue(dc);
83	}
84}
85
86void bcache_dev_sectors_dirty_add(struct cache_set *, unsigned, uint64_t, int);
87
88void bch_sectors_dirty_init(struct cached_dev *dc);
89void bch_cached_dev_writeback_init(struct cached_dev *);
90int bch_cached_dev_writeback_start(struct cached_dev *);
91
92#endif
93