v4.19.13 snapshot.
diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c
new file mode 100644
index 0000000..08c3a9f
--- /dev/null
+++ b/drivers/md/bcache/writeback.c
@@ -0,0 +1,816 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * background writeback - scan btree for dirty data and write it to the backing
+ * device
+ *
+ * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
+ * Copyright 2012 Google, Inc.
+ */
+
+#include "bcache.h"
+#include "btree.h"
+#include "debug.h"
+#include "writeback.h"
+
+#include <linux/delay.h>
+#include <linux/kthread.h>
+#include <linux/sched/clock.h>
+#include <trace/events/bcache.h>
+
+/* Rate limiting */
+static uint64_t __calc_target_rate(struct cached_dev *dc)
+{
+ struct cache_set *c = dc->disk.c;
+
+ /*
+ * This is the size of the cache, minus the amount used for
+ * flash-only devices
+ */
+ uint64_t cache_sectors = c->nbuckets * c->sb.bucket_size -
+ atomic_long_read(&c->flash_dev_dirty_sectors);
+
+ /*
+ * Unfortunately there is no control of global dirty data. If the
+ * user states that they want 10% dirty data in the cache, and has,
+ * e.g., 5 backing volumes of equal size, we try and ensure each
+ * backing volume uses about 2% of the cache for dirty data.
+ */
+ uint32_t bdev_share =
+ div64_u64(bdev_sectors(dc->bdev) << WRITEBACK_SHARE_SHIFT,
+ c->cached_dev_sectors);
+
+ uint64_t cache_dirty_target =
+ div_u64(cache_sectors * dc->writeback_percent, 100);
+
+ /* Ensure each backing dev gets at least one dirty share */
+ if (bdev_share < 1)
+ bdev_share = 1;
+
+ return (cache_dirty_target * bdev_share) >> WRITEBACK_SHARE_SHIFT;
+}
+
+static void __update_writeback_rate(struct cached_dev *dc)
+{
+ /*
+ * PI controller:
+ * Figures out the amount that should be written per second.
+ *
+ * First, the error (number of sectors that are dirty beyond our
+ * target) is calculated. The error is accumulated (numerically
+ * integrated).
+ *
+ * Then, the proportional value and integral value are scaled
+ * based on configured values. These are stored as inverses to
+ * avoid fixed point math and to make configuration easy-- e.g.
+ * the default value of 40 for writeback_rate_p_term_inverse
+ * attempts to write at a rate that would retire all the dirty
+ * blocks in 40 seconds.
+ *
+ * The writeback_rate_i_inverse value of 10000 means that 1/10000th
+ * of the error is accumulated in the integral term per second.
+ * This acts as a slow, long-term average that is not subject to
+ * variations in usage like the p term.
+ */
+ int64_t target = __calc_target_rate(dc);
+ int64_t dirty = bcache_dev_sectors_dirty(&dc->disk);
+ int64_t error = dirty - target;
+ int64_t proportional_scaled =
+ div_s64(error, dc->writeback_rate_p_term_inverse);
+ int64_t integral_scaled;
+ uint32_t new_rate;
+
+ if ((error < 0 && dc->writeback_rate_integral > 0) ||
+ (error > 0 && time_before64(local_clock(),
+ dc->writeback_rate.next + NSEC_PER_MSEC))) {
+ /*
+ * Only decrease the integral term if it's more than
+ * zero. Only increase the integral term if the device
+ * is keeping up. (Don't wind up the integral
+ * ineffectively in either case).
+ *
+ * It's necessary to scale this by
+ * writeback_rate_update_seconds to keep the integral
+ * term dimensioned properly.
+ */
+ dc->writeback_rate_integral += error *
+ dc->writeback_rate_update_seconds;
+ }
+
+ integral_scaled = div_s64(dc->writeback_rate_integral,
+ dc->writeback_rate_i_term_inverse);
+
+ new_rate = clamp_t(int32_t, (proportional_scaled + integral_scaled),
+ dc->writeback_rate_minimum, NSEC_PER_SEC);
+
+ dc->writeback_rate_proportional = proportional_scaled;
+ dc->writeback_rate_integral_scaled = integral_scaled;
+ dc->writeback_rate_change = new_rate -
+ atomic_long_read(&dc->writeback_rate.rate);
+ atomic_long_set(&dc->writeback_rate.rate, new_rate);
+ dc->writeback_rate_target = target;
+}
+
+static bool set_at_max_writeback_rate(struct cache_set *c,
+ struct cached_dev *dc)
+{
+ /*
+ * Idle_counter is increased everytime when update_writeback_rate() is
+ * called. If all backing devices attached to the same cache set have
+ * identical dc->writeback_rate_update_seconds values, it is about 6
+ * rounds of update_writeback_rate() on each backing device before
+ * c->at_max_writeback_rate is set to 1, and then max wrteback rate set
+ * to each dc->writeback_rate.rate.
+ * In order to avoid extra locking cost for counting exact dirty cached
+ * devices number, c->attached_dev_nr is used to calculate the idle
+ * throushold. It might be bigger if not all cached device are in write-
+ * back mode, but it still works well with limited extra rounds of
+ * update_writeback_rate().
+ */
+ if (atomic_inc_return(&c->idle_counter) <
+ atomic_read(&c->attached_dev_nr) * 6)
+ return false;
+
+ if (atomic_read(&c->at_max_writeback_rate) != 1)
+ atomic_set(&c->at_max_writeback_rate, 1);
+
+ atomic_long_set(&dc->writeback_rate.rate, INT_MAX);
+
+ /* keep writeback_rate_target as existing value */
+ dc->writeback_rate_proportional = 0;
+ dc->writeback_rate_integral_scaled = 0;
+ dc->writeback_rate_change = 0;
+
+ /*
+ * Check c->idle_counter and c->at_max_writeback_rate agagain in case
+ * new I/O arrives during before set_at_max_writeback_rate() returns.
+ * Then the writeback rate is set to 1, and its new value should be
+ * decided via __update_writeback_rate().
+ */
+ if ((atomic_read(&c->idle_counter) <
+ atomic_read(&c->attached_dev_nr) * 6) ||
+ !atomic_read(&c->at_max_writeback_rate))
+ return false;
+
+ return true;
+}
+
+static void update_writeback_rate(struct work_struct *work)
+{
+ struct cached_dev *dc = container_of(to_delayed_work(work),
+ struct cached_dev,
+ writeback_rate_update);
+ struct cache_set *c = dc->disk.c;
+
+ /*
+ * should check BCACHE_DEV_RATE_DW_RUNNING before calling
+ * cancel_delayed_work_sync().
+ */
+ set_bit(BCACHE_DEV_RATE_DW_RUNNING, &dc->disk.flags);
+ /* paired with where BCACHE_DEV_RATE_DW_RUNNING is tested */
+ smp_mb();
+
+ /*
+ * CACHE_SET_IO_DISABLE might be set via sysfs interface,
+ * check it here too.
+ */
+ if (!test_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags) ||
+ test_bit(CACHE_SET_IO_DISABLE, &c->flags)) {
+ clear_bit(BCACHE_DEV_RATE_DW_RUNNING, &dc->disk.flags);
+ /* paired with where BCACHE_DEV_RATE_DW_RUNNING is tested */
+ smp_mb();
+ return;
+ }
+
+ if (atomic_read(&dc->has_dirty) && dc->writeback_percent) {
+ /*
+ * If the whole cache set is idle, set_at_max_writeback_rate()
+ * will set writeback rate to a max number. Then it is
+ * unncessary to update writeback rate for an idle cache set
+ * in maximum writeback rate number(s).
+ */
+ if (!set_at_max_writeback_rate(c, dc)) {
+ down_read(&dc->writeback_lock);
+ __update_writeback_rate(dc);
+ up_read(&dc->writeback_lock);
+ }
+ }
+
+
+ /*
+ * CACHE_SET_IO_DISABLE might be set via sysfs interface,
+ * check it here too.
+ */
+ if (test_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags) &&
+ !test_bit(CACHE_SET_IO_DISABLE, &c->flags)) {
+ schedule_delayed_work(&dc->writeback_rate_update,
+ dc->writeback_rate_update_seconds * HZ);
+ }
+
+ /*
+ * should check BCACHE_DEV_RATE_DW_RUNNING before calling
+ * cancel_delayed_work_sync().
+ */
+ clear_bit(BCACHE_DEV_RATE_DW_RUNNING, &dc->disk.flags);
+ /* paired with where BCACHE_DEV_RATE_DW_RUNNING is tested */
+ smp_mb();
+}
+
+static unsigned int writeback_delay(struct cached_dev *dc,
+ unsigned int sectors)
+{
+ if (test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) ||
+ !dc->writeback_percent)
+ return 0;
+
+ return bch_next_delay(&dc->writeback_rate, sectors);
+}
+
+struct dirty_io {
+ struct closure cl;
+ struct cached_dev *dc;
+ uint16_t sequence;
+ struct bio bio;
+};
+
+static void dirty_init(struct keybuf_key *w)
+{
+ struct dirty_io *io = w->private;
+ struct bio *bio = &io->bio;
+
+ bio_init(bio, bio->bi_inline_vecs,
+ DIV_ROUND_UP(KEY_SIZE(&w->key), PAGE_SECTORS));
+ if (!io->dc->writeback_percent)
+ bio_set_prio(bio, IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0));
+
+ bio->bi_iter.bi_size = KEY_SIZE(&w->key) << 9;
+ bio->bi_private = w;
+ bch_bio_map(bio, NULL);
+}
+
+static void dirty_io_destructor(struct closure *cl)
+{
+ struct dirty_io *io = container_of(cl, struct dirty_io, cl);
+
+ kfree(io);
+}
+
+static void write_dirty_finish(struct closure *cl)
+{
+ struct dirty_io *io = container_of(cl, struct dirty_io, cl);
+ struct keybuf_key *w = io->bio.bi_private;
+ struct cached_dev *dc = io->dc;
+
+ bio_free_pages(&io->bio);
+
+ /* This is kind of a dumb way of signalling errors. */
+ if (KEY_DIRTY(&w->key)) {
+ int ret;
+ unsigned int i;
+ struct keylist keys;
+
+ bch_keylist_init(&keys);
+
+ bkey_copy(keys.top, &w->key);
+ SET_KEY_DIRTY(keys.top, false);
+ bch_keylist_push(&keys);
+
+ for (i = 0; i < KEY_PTRS(&w->key); i++)
+ atomic_inc(&PTR_BUCKET(dc->disk.c, &w->key, i)->pin);
+
+ ret = bch_btree_insert(dc->disk.c, &keys, NULL, &w->key);
+
+ if (ret)
+ trace_bcache_writeback_collision(&w->key);
+
+ atomic_long_inc(ret
+ ? &dc->disk.c->writeback_keys_failed
+ : &dc->disk.c->writeback_keys_done);
+ }
+
+ bch_keybuf_del(&dc->writeback_keys, w);
+ up(&dc->in_flight);
+
+ closure_return_with_destructor(cl, dirty_io_destructor);
+}
+
+static void dirty_endio(struct bio *bio)
+{
+ struct keybuf_key *w = bio->bi_private;
+ struct dirty_io *io = w->private;
+
+ if (bio->bi_status) {
+ SET_KEY_DIRTY(&w->key, false);
+ bch_count_backing_io_errors(io->dc, bio);
+ }
+
+ closure_put(&io->cl);
+}
+
+static void write_dirty(struct closure *cl)
+{
+ struct dirty_io *io = container_of(cl, struct dirty_io, cl);
+ struct keybuf_key *w = io->bio.bi_private;
+ struct cached_dev *dc = io->dc;
+
+ uint16_t next_sequence;
+
+ if (atomic_read(&dc->writeback_sequence_next) != io->sequence) {
+ /* Not our turn to write; wait for a write to complete */
+ closure_wait(&dc->writeback_ordering_wait, cl);
+
+ if (atomic_read(&dc->writeback_sequence_next) == io->sequence) {
+ /*
+ * Edge case-- it happened in indeterminate order
+ * relative to when we were added to wait list..
+ */
+ closure_wake_up(&dc->writeback_ordering_wait);
+ }
+
+ continue_at(cl, write_dirty, io->dc->writeback_write_wq);
+ return;
+ }
+
+ next_sequence = io->sequence + 1;
+
+ /*
+ * IO errors are signalled using the dirty bit on the key.
+ * If we failed to read, we should not attempt to write to the
+ * backing device. Instead, immediately go to write_dirty_finish
+ * to clean up.
+ */
+ if (KEY_DIRTY(&w->key)) {
+ dirty_init(w);
+ bio_set_op_attrs(&io->bio, REQ_OP_WRITE, 0);
+ io->bio.bi_iter.bi_sector = KEY_START(&w->key);
+ bio_set_dev(&io->bio, io->dc->bdev);
+ io->bio.bi_end_io = dirty_endio;
+
+ /* I/O request sent to backing device */
+ closure_bio_submit(io->dc->disk.c, &io->bio, cl);
+ }
+
+ atomic_set(&dc->writeback_sequence_next, next_sequence);
+ closure_wake_up(&dc->writeback_ordering_wait);
+
+ continue_at(cl, write_dirty_finish, io->dc->writeback_write_wq);
+}
+
+static void read_dirty_endio(struct bio *bio)
+{
+ struct keybuf_key *w = bio->bi_private;
+ struct dirty_io *io = w->private;
+
+ /* is_read = 1 */
+ bch_count_io_errors(PTR_CACHE(io->dc->disk.c, &w->key, 0),
+ bio->bi_status, 1,
+ "reading dirty data from cache");
+
+ dirty_endio(bio);
+}
+
+static void read_dirty_submit(struct closure *cl)
+{
+ struct dirty_io *io = container_of(cl, struct dirty_io, cl);
+
+ closure_bio_submit(io->dc->disk.c, &io->bio, cl);
+
+ continue_at(cl, write_dirty, io->dc->writeback_write_wq);
+}
+
+static void read_dirty(struct cached_dev *dc)
+{
+ unsigned int delay = 0;
+ struct keybuf_key *next, *keys[MAX_WRITEBACKS_IN_PASS], *w;
+ size_t size;
+ int nk, i;
+ struct dirty_io *io;
+ struct closure cl;
+ uint16_t sequence = 0;
+
+ BUG_ON(!llist_empty(&dc->writeback_ordering_wait.list));
+ atomic_set(&dc->writeback_sequence_next, sequence);
+ closure_init_stack(&cl);
+
+ /*
+ * XXX: if we error, background writeback just spins. Should use some
+ * mempools.
+ */
+
+ next = bch_keybuf_next(&dc->writeback_keys);
+
+ while (!kthread_should_stop() &&
+ !test_bit(CACHE_SET_IO_DISABLE, &dc->disk.c->flags) &&
+ next) {
+ size = 0;
+ nk = 0;
+
+ do {
+ BUG_ON(ptr_stale(dc->disk.c, &next->key, 0));
+
+ /*
+ * Don't combine too many operations, even if they
+ * are all small.
+ */
+ if (nk >= MAX_WRITEBACKS_IN_PASS)
+ break;
+
+ /*
+ * If the current operation is very large, don't
+ * further combine operations.
+ */
+ if (size >= MAX_WRITESIZE_IN_PASS)
+ break;
+
+ /*
+ * Operations are only eligible to be combined
+ * if they are contiguous.
+ *
+ * TODO: add a heuristic willing to fire a
+ * certain amount of non-contiguous IO per pass,
+ * so that we can benefit from backing device
+ * command queueing.
+ */
+ if ((nk != 0) && bkey_cmp(&keys[nk-1]->key,
+ &START_KEY(&next->key)))
+ break;
+
+ size += KEY_SIZE(&next->key);
+ keys[nk++] = next;
+ } while ((next = bch_keybuf_next(&dc->writeback_keys)));
+
+ /* Now we have gathered a set of 1..5 keys to write back. */
+ for (i = 0; i < nk; i++) {
+ w = keys[i];
+
+ io = kzalloc(sizeof(struct dirty_io) +
+ sizeof(struct bio_vec) *
+ DIV_ROUND_UP(KEY_SIZE(&w->key),
+ PAGE_SECTORS),
+ GFP_KERNEL);
+ if (!io)
+ goto err;
+
+ w->private = io;
+ io->dc = dc;
+ io->sequence = sequence++;
+
+ dirty_init(w);
+ bio_set_op_attrs(&io->bio, REQ_OP_READ, 0);
+ io->bio.bi_iter.bi_sector = PTR_OFFSET(&w->key, 0);
+ bio_set_dev(&io->bio,
+ PTR_CACHE(dc->disk.c, &w->key, 0)->bdev);
+ io->bio.bi_end_io = read_dirty_endio;
+
+ if (bch_bio_alloc_pages(&io->bio, GFP_KERNEL))
+ goto err_free;
+
+ trace_bcache_writeback(&w->key);
+
+ down(&dc->in_flight);
+
+ /*
+ * We've acquired a semaphore for the maximum
+ * simultaneous number of writebacks; from here
+ * everything happens asynchronously.
+ */
+ closure_call(&io->cl, read_dirty_submit, NULL, &cl);
+ }
+
+ delay = writeback_delay(dc, size);
+
+ while (!kthread_should_stop() &&
+ !test_bit(CACHE_SET_IO_DISABLE, &dc->disk.c->flags) &&
+ delay) {
+ schedule_timeout_interruptible(delay);
+ delay = writeback_delay(dc, 0);
+ }
+ }
+
+ if (0) {
+err_free:
+ kfree(w->private);
+err:
+ bch_keybuf_del(&dc->writeback_keys, w);
+ }
+
+ /*
+ * Wait for outstanding writeback IOs to finish (and keybuf slots to be
+ * freed) before refilling again
+ */
+ closure_sync(&cl);
+}
+
+/* Scan for dirty data */
+
+void bcache_dev_sectors_dirty_add(struct cache_set *c, unsigned int inode,
+ uint64_t offset, int nr_sectors)
+{
+ struct bcache_device *d = c->devices[inode];
+ unsigned int stripe_offset, stripe, sectors_dirty;
+
+ if (!d)
+ return;
+
+ if (UUID_FLASH_ONLY(&c->uuids[inode]))
+ atomic_long_add(nr_sectors, &c->flash_dev_dirty_sectors);
+
+ stripe = offset_to_stripe(d, offset);
+ stripe_offset = offset & (d->stripe_size - 1);
+
+ while (nr_sectors) {
+ int s = min_t(unsigned int, abs(nr_sectors),
+ d->stripe_size - stripe_offset);
+
+ if (nr_sectors < 0)
+ s = -s;
+
+ if (stripe >= d->nr_stripes)
+ return;
+
+ sectors_dirty = atomic_add_return(s,
+ d->stripe_sectors_dirty + stripe);
+ if (sectors_dirty == d->stripe_size)
+ set_bit(stripe, d->full_dirty_stripes);
+ else
+ clear_bit(stripe, d->full_dirty_stripes);
+
+ nr_sectors -= s;
+ stripe_offset = 0;
+ stripe++;
+ }
+}
+
+static bool dirty_pred(struct keybuf *buf, struct bkey *k)
+{
+ struct cached_dev *dc = container_of(buf,
+ struct cached_dev,
+ writeback_keys);
+
+ BUG_ON(KEY_INODE(k) != dc->disk.id);
+
+ return KEY_DIRTY(k);
+}
+
+static void refill_full_stripes(struct cached_dev *dc)
+{
+ struct keybuf *buf = &dc->writeback_keys;
+ unsigned int start_stripe, stripe, next_stripe;
+ bool wrapped = false;
+
+ stripe = offset_to_stripe(&dc->disk, KEY_OFFSET(&buf->last_scanned));
+
+ if (stripe >= dc->disk.nr_stripes)
+ stripe = 0;
+
+ start_stripe = stripe;
+
+ while (1) {
+ stripe = find_next_bit(dc->disk.full_dirty_stripes,
+ dc->disk.nr_stripes, stripe);
+
+ if (stripe == dc->disk.nr_stripes)
+ goto next;
+
+ next_stripe = find_next_zero_bit(dc->disk.full_dirty_stripes,
+ dc->disk.nr_stripes, stripe);
+
+ buf->last_scanned = KEY(dc->disk.id,
+ stripe * dc->disk.stripe_size, 0);
+
+ bch_refill_keybuf(dc->disk.c, buf,
+ &KEY(dc->disk.id,
+ next_stripe * dc->disk.stripe_size, 0),
+ dirty_pred);
+
+ if (array_freelist_empty(&buf->freelist))
+ return;
+
+ stripe = next_stripe;
+next:
+ if (wrapped && stripe > start_stripe)
+ return;
+
+ if (stripe == dc->disk.nr_stripes) {
+ stripe = 0;
+ wrapped = true;
+ }
+ }
+}
+
+/*
+ * Returns true if we scanned the entire disk
+ */
+static bool refill_dirty(struct cached_dev *dc)
+{
+ struct keybuf *buf = &dc->writeback_keys;
+ struct bkey start = KEY(dc->disk.id, 0, 0);
+ struct bkey end = KEY(dc->disk.id, MAX_KEY_OFFSET, 0);
+ struct bkey start_pos;
+
+ /*
+ * make sure keybuf pos is inside the range for this disk - at bringup
+ * we might not be attached yet so this disk's inode nr isn't
+ * initialized then
+ */
+ if (bkey_cmp(&buf->last_scanned, &start) < 0 ||
+ bkey_cmp(&buf->last_scanned, &end) > 0)
+ buf->last_scanned = start;
+
+ if (dc->partial_stripes_expensive) {
+ refill_full_stripes(dc);
+ if (array_freelist_empty(&buf->freelist))
+ return false;
+ }
+
+ start_pos = buf->last_scanned;
+ bch_refill_keybuf(dc->disk.c, buf, &end, dirty_pred);
+
+ if (bkey_cmp(&buf->last_scanned, &end) < 0)
+ return false;
+
+ /*
+ * If we get to the end start scanning again from the beginning, and
+ * only scan up to where we initially started scanning from:
+ */
+ buf->last_scanned = start;
+ bch_refill_keybuf(dc->disk.c, buf, &start_pos, dirty_pred);
+
+ return bkey_cmp(&buf->last_scanned, &start_pos) >= 0;
+}
+
+static int bch_writeback_thread(void *arg)
+{
+ struct cached_dev *dc = arg;
+ struct cache_set *c = dc->disk.c;
+ bool searched_full_index;
+
+ bch_ratelimit_reset(&dc->writeback_rate);
+
+ while (!kthread_should_stop() &&
+ !test_bit(CACHE_SET_IO_DISABLE, &c->flags)) {
+ down_write(&dc->writeback_lock);
+ set_current_state(TASK_INTERRUPTIBLE);
+ /*
+ * If the bache device is detaching, skip here and continue
+ * to perform writeback. Otherwise, if no dirty data on cache,
+ * or there is dirty data on cache but writeback is disabled,
+ * the writeback thread should sleep here and wait for others
+ * to wake up it.
+ */
+ if (!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) &&
+ (!atomic_read(&dc->has_dirty) || !dc->writeback_running)) {
+ up_write(&dc->writeback_lock);
+
+ if (kthread_should_stop() ||
+ test_bit(CACHE_SET_IO_DISABLE, &c->flags)) {
+ set_current_state(TASK_RUNNING);
+ break;
+ }
+
+ schedule();
+ continue;
+ }
+ set_current_state(TASK_RUNNING);
+
+ searched_full_index = refill_dirty(dc);
+
+ if (searched_full_index &&
+ RB_EMPTY_ROOT(&dc->writeback_keys.keys)) {
+ atomic_set(&dc->has_dirty, 0);
+ SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN);
+ bch_write_bdev_super(dc, NULL);
+ /*
+ * If bcache device is detaching via sysfs interface,
+ * writeback thread should stop after there is no dirty
+ * data on cache. BCACHE_DEV_DETACHING flag is set in
+ * bch_cached_dev_detach().
+ */
+ if (test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)) {
+ up_write(&dc->writeback_lock);
+ break;
+ }
+ }
+
+ up_write(&dc->writeback_lock);
+
+ read_dirty(dc);
+
+ if (searched_full_index) {
+ unsigned int delay = dc->writeback_delay * HZ;
+
+ while (delay &&
+ !kthread_should_stop() &&
+ !test_bit(CACHE_SET_IO_DISABLE, &c->flags) &&
+ !test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags))
+ delay = schedule_timeout_interruptible(delay);
+
+ bch_ratelimit_reset(&dc->writeback_rate);
+ }
+ }
+
+ cached_dev_put(dc);
+ wait_for_kthread_stop();
+
+ return 0;
+}
+
+/* Init */
+#define INIT_KEYS_EACH_TIME 500000
+#define INIT_KEYS_SLEEP_MS 100
+
+struct sectors_dirty_init {
+ struct btree_op op;
+ unsigned int inode;
+ size_t count;
+ struct bkey start;
+};
+
+static int sectors_dirty_init_fn(struct btree_op *_op, struct btree *b,
+ struct bkey *k)
+{
+ struct sectors_dirty_init *op = container_of(_op,
+ struct sectors_dirty_init, op);
+ if (KEY_INODE(k) > op->inode)
+ return MAP_DONE;
+
+ if (KEY_DIRTY(k))
+ bcache_dev_sectors_dirty_add(b->c, KEY_INODE(k),
+ KEY_START(k), KEY_SIZE(k));
+
+ op->count++;
+ if (atomic_read(&b->c->search_inflight) &&
+ !(op->count % INIT_KEYS_EACH_TIME)) {
+ bkey_copy_key(&op->start, k);
+ return -EAGAIN;
+ }
+
+ return MAP_CONTINUE;
+}
+
+void bch_sectors_dirty_init(struct bcache_device *d)
+{
+ struct sectors_dirty_init op;
+ int ret;
+
+ bch_btree_op_init(&op.op, -1);
+ op.inode = d->id;
+ op.count = 0;
+ op.start = KEY(op.inode, 0, 0);
+
+ do {
+ ret = bch_btree_map_keys(&op.op, d->c, &op.start,
+ sectors_dirty_init_fn, 0);
+ if (ret == -EAGAIN)
+ schedule_timeout_interruptible(
+ msecs_to_jiffies(INIT_KEYS_SLEEP_MS));
+ else if (ret < 0) {
+ pr_warn("sectors dirty init failed, ret=%d!", ret);
+ break;
+ }
+ } while (ret == -EAGAIN);
+}
+
+void bch_cached_dev_writeback_init(struct cached_dev *dc)
+{
+ sema_init(&dc->in_flight, 64);
+ init_rwsem(&dc->writeback_lock);
+ bch_keybuf_init(&dc->writeback_keys);
+
+ dc->writeback_metadata = true;
+ dc->writeback_running = true;
+ dc->writeback_percent = 10;
+ dc->writeback_delay = 30;
+ atomic_long_set(&dc->writeback_rate.rate, 1024);
+ dc->writeback_rate_minimum = 8;
+
+ dc->writeback_rate_update_seconds = WRITEBACK_RATE_UPDATE_SECS_DEFAULT;
+ dc->writeback_rate_p_term_inverse = 40;
+ dc->writeback_rate_i_term_inverse = 10000;
+
+ WARN_ON(test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags));
+ INIT_DELAYED_WORK(&dc->writeback_rate_update, update_writeback_rate);
+}
+
+int bch_cached_dev_writeback_start(struct cached_dev *dc)
+{
+ dc->writeback_write_wq = alloc_workqueue("bcache_writeback_wq",
+ WQ_MEM_RECLAIM, 0);
+ if (!dc->writeback_write_wq)
+ return -ENOMEM;
+
+ cached_dev_get(dc);
+ dc->writeback_thread = kthread_create(bch_writeback_thread, dc,
+ "bcache_writeback");
+ if (IS_ERR(dc->writeback_thread)) {
+ cached_dev_put(dc);
+ return PTR_ERR(dc->writeback_thread);
+ }
+
+ WARN_ON(test_and_set_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags));
+ schedule_delayed_work(&dc->writeback_rate_update,
+ dc->writeback_rate_update_seconds * HZ);
+
+ bch_writeback_queue(dc);
+
+ return 0;
+}