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// SPDX-License-Identifier: GPL-2.0
#include "bcachefs.h"
#include "journal.h"
#include "journal_io.h"
#include "journal_reclaim.h"
#include "replicas.h"
#include "super.h"
/* Free space calculations: */
static unsigned journal_space_from(struct journal_device *ja,
enum journal_space_from from)
{
switch (from) {
case journal_space_discarded:
return ja->discard_idx;
case journal_space_clean_ondisk:
return ja->dirty_idx_ondisk;
case journal_space_clean:
return ja->dirty_idx;
default:
BUG();
}
}
unsigned bch2_journal_dev_buckets_available(struct journal *j,
struct journal_device *ja,
enum journal_space_from from)
{
unsigned available = (journal_space_from(ja, from) -
ja->cur_idx - 1 + ja->nr) % ja->nr;
/*
* Don't use the last bucket unless writing the new last_seq
* will make another bucket available:
*/
if (available && ja->dirty_idx_ondisk == ja->dirty_idx)
--available;
return available;
}
static void journal_set_remaining(struct journal *j, unsigned u64s_remaining)
{
union journal_preres_state old, new;
u64 v = atomic64_read(&j->prereserved.counter);
do {
old.v = new.v = v;
new.remaining = u64s_remaining;
} while ((v = atomic64_cmpxchg(&j->prereserved.counter,
old.v, new.v)) != old.v);
}
static struct journal_space {
unsigned next_entry;
unsigned remaining;
} __journal_space_available(struct journal *j, unsigned nr_devs_want,
enum journal_space_from from)
{
struct bch_fs *c = container_of(j, struct bch_fs, journal);
struct bch_dev *ca;
unsigned sectors_next_entry = UINT_MAX;
unsigned sectors_total = UINT_MAX;
unsigned i, nr_devs = 0;
unsigned unwritten_sectors = j->reservations.prev_buf_unwritten
? journal_prev_buf(j)->sectors
: 0;
rcu_read_lock();
for_each_member_device_rcu(ca, c, i,
&c->rw_devs[BCH_DATA_journal]) {
struct journal_device *ja = &ca->journal;
unsigned buckets_this_device, sectors_this_device;
if (!ja->nr)
continue;
buckets_this_device = bch2_journal_dev_buckets_available(j, ja, from);
sectors_this_device = ja->sectors_free;
/*
* We that we don't allocate the space for a journal entry
* until we write it out - thus, account for it here:
*/
if (unwritten_sectors >= sectors_this_device) {
if (!buckets_this_device)
continue;
buckets_this_device--;
sectors_this_device = ca->mi.bucket_size;
}
sectors_this_device -= unwritten_sectors;
if (sectors_this_device < ca->mi.bucket_size &&
buckets_this_device) {
buckets_this_device--;
sectors_this_device = ca->mi.bucket_size;
}
if (!sectors_this_device)
continue;
sectors_next_entry = min(sectors_next_entry,
sectors_this_device);
sectors_total = min(sectors_total,
buckets_this_device * ca->mi.bucket_size +
sectors_this_device);
nr_devs++;
}
rcu_read_unlock();
if (nr_devs < nr_devs_want)
return (struct journal_space) { 0, 0 };
return (struct journal_space) {
.next_entry = sectors_next_entry,
.remaining = max_t(int, 0, sectors_total - sectors_next_entry),
};
}
void bch2_journal_space_available(struct journal *j)
{
struct bch_fs *c = container_of(j, struct bch_fs, journal);
struct bch_dev *ca;
struct journal_space discarded, clean_ondisk, clean;
unsigned overhead, u64s_remaining = 0;
unsigned max_entry_size = min(j->buf[0].buf_size >> 9,
j->buf[1].buf_size >> 9);
unsigned i, nr_online = 0, nr_devs_want;
bool can_discard = false;
int ret = 0;
lockdep_assert_held(&j->lock);
rcu_read_lock();
for_each_member_device_rcu(ca, c, i,
&c->rw_devs[BCH_DATA_journal]) {
struct journal_device *ja = &ca->journal;
if (!ja->nr)
continue;
while (ja->dirty_idx != ja->cur_idx &&
ja->bucket_seq[ja->dirty_idx] < journal_last_seq(j))
ja->dirty_idx = (ja->dirty_idx + 1) % ja->nr;
while (ja->dirty_idx_ondisk != ja->dirty_idx &&
ja->bucket_seq[ja->dirty_idx_ondisk] < j->last_seq_ondisk)
ja->dirty_idx_ondisk = (ja->dirty_idx_ondisk + 1) % ja->nr;
if (ja->discard_idx != ja->dirty_idx_ondisk)
can_discard = true;
max_entry_size = min_t(unsigned, max_entry_size, ca->mi.bucket_size);
nr_online++;
}
rcu_read_unlock();
j->can_discard = can_discard;
if (nr_online < c->opts.metadata_replicas_required) {
ret = -EROFS;
goto out;
}
if (!fifo_free(&j->pin)) {
ret = -ENOSPC;
goto out;
}
nr_devs_want = min_t(unsigned, nr_online, c->opts.metadata_replicas);
discarded = __journal_space_available(j, nr_devs_want, journal_space_discarded);
clean_ondisk = __journal_space_available(j, nr_devs_want, journal_space_clean_ondisk);
clean = __journal_space_available(j, nr_devs_want, journal_space_clean);
if (!discarded.next_entry)
ret = -ENOSPC;
overhead = DIV_ROUND_UP(clean.remaining, max_entry_size) *
journal_entry_overhead(j);
u64s_remaining = clean.remaining << 6;
u64s_remaining = max_t(int, 0, u64s_remaining - overhead);
u64s_remaining /= 4;
out:
j->cur_entry_sectors = !ret ? discarded.next_entry : 0;
j->cur_entry_error = ret;
journal_set_remaining(j, u64s_remaining);
journal_check_may_get_unreserved(j);
if (!ret)
journal_wake(j);
}
/* Discards - last part of journal reclaim: */
static bool should_discard_bucket(struct journal *j, struct journal_device *ja)
{
bool ret;
spin_lock(&j->lock);
ret = ja->discard_idx != ja->dirty_idx_ondisk;
spin_unlock(&j->lock);
return ret;
}
/*
* Advance ja->discard_idx as long as it points to buckets that are no longer
* dirty, issuing discards if necessary:
*/
void bch2_journal_do_discards(struct journal *j)
{
struct bch_fs *c = container_of(j, struct bch_fs, journal);
struct bch_dev *ca;
unsigned iter;
mutex_lock(&j->discard_lock);
for_each_rw_member(ca, c, iter) {
struct journal_device *ja = &ca->journal;
while (should_discard_bucket(j, ja)) {
if (ca->mi.discard &&
bdev_max_discard_sectors(ca->disk_sb.bdev))
blkdev_issue_discard(ca->disk_sb.bdev,
bucket_to_sector(ca,
ja->buckets[ja->discard_idx]),
ca->mi.bucket_size, GFP_NOIO);
spin_lock(&j->lock);
ja->discard_idx = (ja->discard_idx + 1) % ja->nr;
bch2_journal_space_available(j);
spin_unlock(&j->lock);
}
}
mutex_unlock(&j->discard_lock);
}
/*
* Journal entry pinning - machinery for holding a reference on a given journal
* entry, holding it open to ensure it gets replayed during recovery:
*/
static void bch2_journal_reclaim_fast(struct journal *j)
{
struct journal_entry_pin_list temp;
bool popped = false;
lockdep_assert_held(&j->lock);
/*
* Unpin journal entries whose reference counts reached zero, meaning
* all btree nodes got written out
*/
while (!fifo_empty(&j->pin) &&
!atomic_read(&fifo_peek_front(&j->pin).count)) {
BUG_ON(!list_empty(&fifo_peek_front(&j->pin).list));
BUG_ON(!fifo_pop(&j->pin, temp));
popped = true;
}
if (popped)
bch2_journal_space_available(j);
}
void bch2_journal_pin_put(struct journal *j, u64 seq)
{
struct journal_entry_pin_list *pin_list = journal_seq_pin(j, seq);
if (atomic_dec_and_test(&pin_list->count)) {
spin_lock(&j->lock);
bch2_journal_reclaim_fast(j);
spin_unlock(&j->lock);
}
}
static inline void __journal_pin_drop(struct journal *j,
struct journal_entry_pin *pin)
{
struct journal_entry_pin_list *pin_list;
if (!journal_pin_active(pin))
return;
pin_list = journal_seq_pin(j, pin->seq);
pin->seq = 0;
list_del_init(&pin->list);
/*
* Unpinning a journal entry make make journal_next_bucket() succeed, if
* writing a new last_seq will now make another bucket available:
*/
if (atomic_dec_and_test(&pin_list->count) &&
pin_list == &fifo_peek_front(&j->pin))
bch2_journal_reclaim_fast(j);
else if (fifo_used(&j->pin) == 1 &&
atomic_read(&pin_list->count) == 1)
journal_wake(j);
}
void bch2_journal_pin_drop(struct journal *j,
struct journal_entry_pin *pin)
{
spin_lock(&j->lock);
__journal_pin_drop(j, pin);
spin_unlock(&j->lock);
}
static void bch2_journal_pin_add_locked(struct journal *j, u64 seq,
struct journal_entry_pin *pin,
journal_pin_flush_fn flush_fn)
{
struct journal_entry_pin_list *pin_list = journal_seq_pin(j, seq);
__journal_pin_drop(j, pin);
BUG_ON(!atomic_read(&pin_list->count) && seq == journal_last_seq(j));
atomic_inc(&pin_list->count);
pin->seq = seq;
pin->flush = flush_fn;
list_add(&pin->list, flush_fn ? &pin_list->list : &pin_list->flushed);
}
void __bch2_journal_pin_add(struct journal *j, u64 seq,
struct journal_entry_pin *pin,
journal_pin_flush_fn flush_fn)
{
spin_lock(&j->lock);
bch2_journal_pin_add_locked(j, seq, pin, flush_fn);
spin_unlock(&j->lock);
/*
* If the journal is currently full, we might want to call flush_fn
* immediately:
*/
journal_wake(j);
}
void bch2_journal_pin_update(struct journal *j, u64 seq,
struct journal_entry_pin *pin,
journal_pin_flush_fn flush_fn)
{
if (journal_pin_active(pin) && pin->seq < seq)
return;
spin_lock(&j->lock);
if (pin->seq != seq) {
bch2_journal_pin_add_locked(j, seq, pin, flush_fn);
} else {
struct journal_entry_pin_list *pin_list =
journal_seq_pin(j, seq);
/*
* If the pin is already pinning the right sequence number, it
* still might've already been flushed:
*/
list_move(&pin->list, &pin_list->list);
}
spin_unlock(&j->lock);
/*
* If the journal is currently full, we might want to call flush_fn
* immediately:
*/
journal_wake(j);
}
void bch2_journal_pin_copy(struct journal *j,
struct journal_entry_pin *dst,
struct journal_entry_pin *src,
journal_pin_flush_fn flush_fn)
{
spin_lock(&j->lock);
if (journal_pin_active(src) &&
(!journal_pin_active(dst) || src->seq < dst->seq))
bch2_journal_pin_add_locked(j, src->seq, dst, flush_fn);
spin_unlock(&j->lock);
}
/**
* bch2_journal_pin_flush: ensure journal pin callback is no longer running
*/
void bch2_journal_pin_flush(struct journal *j, struct journal_entry_pin *pin)
{
BUG_ON(journal_pin_active(pin));
wait_event(j->pin_flush_wait, j->flush_in_progress != pin);
}
/*
* Journal reclaim: flush references to open journal entries to reclaim space in
* the journal
*
* May be done by the journal code in the background as needed to free up space
* for more journal entries, or as part of doing a clean shutdown, or to migrate
* data off of a specific device:
*/
static struct journal_entry_pin *
journal_get_next_pin(struct journal *j, u64 max_seq, u64 *seq)
{
struct journal_entry_pin_list *pin_list;
struct journal_entry_pin *ret = NULL;
if (!test_bit(JOURNAL_RECLAIM_STARTED, &j->flags))
return NULL;
spin_lock(&j->lock);
fifo_for_each_entry_ptr(pin_list, &j->pin, *seq)
if (*seq > max_seq ||
(ret = list_first_entry_or_null(&pin_list->list,
struct journal_entry_pin, list)))
break;
if (ret) {
list_move(&ret->list, &pin_list->flushed);
BUG_ON(j->flush_in_progress);
j->flush_in_progress = ret;
j->last_flushed = jiffies;
}
spin_unlock(&j->lock);
return ret;
}
/* returns true if we did work */
static bool journal_flush_pins(struct journal *j, u64 seq_to_flush,
unsigned min_nr)
{
struct journal_entry_pin *pin;
bool ret = false;
u64 seq;
lockdep_assert_held(&j->reclaim_lock);
while ((pin = journal_get_next_pin(j, min_nr
? U64_MAX : seq_to_flush, &seq))) {
if (min_nr)
min_nr--;
pin->flush(j, pin, seq);
BUG_ON(j->flush_in_progress != pin);
j->flush_in_progress = NULL;
wake_up(&j->pin_flush_wait);
ret = true;
}
return ret;
}
/**
* bch2_journal_reclaim - free up journal buckets
*
* Background journal reclaim writes out btree nodes. It should be run
* early enough so that we never completely run out of journal buckets.
*
* High watermarks for triggering background reclaim:
* - FIFO has fewer than 512 entries left
* - fewer than 25% journal buckets free
*
* Background reclaim runs until low watermarks are reached:
* - FIFO has more than 1024 entries left
* - more than 50% journal buckets free
*
* As long as a reclaim can complete in the time it takes to fill up
* 512 journal entries or 25% of all journal buckets, then
* journal_next_bucket() should not stall.
*/
void bch2_journal_reclaim(struct journal *j)
{
struct bch_fs *c = container_of(j, struct bch_fs, journal);
struct bch_dev *ca;
unsigned iter, min_nr = 0;
u64 seq_to_flush = 0;
lockdep_assert_held(&j->reclaim_lock);
bch2_journal_do_discards(j);
spin_lock(&j->lock);
for_each_rw_member(ca, c, iter) {
struct journal_device *ja = &ca->journal;
unsigned nr_buckets, bucket_to_flush;
if (!ja->nr)
continue;
/* Try to keep the journal at most half full: */
nr_buckets = ja->nr / 2;
/* And include pre-reservations: */
nr_buckets += DIV_ROUND_UP(j->prereserved.reserved,
(ca->mi.bucket_size << 6) -
journal_entry_overhead(j));
nr_buckets = min(nr_buckets, ja->nr);
bucket_to_flush = (ja->cur_idx + nr_buckets) % ja->nr;
seq_to_flush = max(seq_to_flush,
ja->bucket_seq[bucket_to_flush]);
}
/* Also flush if the pin fifo is more than half full */
seq_to_flush = max_t(s64, seq_to_flush,
(s64) journal_cur_seq(j) -
(j->pin.size >> 1));
spin_unlock(&j->lock);
/*
* If it's been longer than j->reclaim_delay_ms since we last flushed,
* make sure to flush at least one journal pin:
*/
if (time_after(jiffies, j->last_flushed +
msecs_to_jiffies(j->reclaim_delay_ms)))
min_nr = 1;
if (j->prereserved.reserved * 2 > j->prereserved.remaining) {
seq_to_flush = max(seq_to_flush, journal_last_seq(j));
min_nr = 1;
}
journal_flush_pins(j, seq_to_flush, min_nr);
if (!bch2_journal_error(j))
queue_delayed_work(c->journal_reclaim_wq, &j->reclaim_work,
msecs_to_jiffies(j->reclaim_delay_ms));
}
void bch2_journal_reclaim_work(struct work_struct *work)
{
struct journal *j = container_of(to_delayed_work(work),
struct journal, reclaim_work);
mutex_lock(&j->reclaim_lock);
bch2_journal_reclaim(j);
mutex_unlock(&j->reclaim_lock);
}
static int journal_flush_done(struct journal *j, u64 seq_to_flush,
bool *did_work)
{
int ret;
ret = bch2_journal_error(j);
if (ret)
return ret;
mutex_lock(&j->reclaim_lock);
*did_work = journal_flush_pins(j, seq_to_flush, 0);
spin_lock(&j->lock);
/*
* If journal replay hasn't completed, the unreplayed journal entries
* hold refs on their corresponding sequence numbers
*/
ret = !test_bit(JOURNAL_REPLAY_DONE, &j->flags) ||
journal_last_seq(j) > seq_to_flush ||
(fifo_used(&j->pin) == 1 &&
atomic_read(&fifo_peek_front(&j->pin).count) == 1);
spin_unlock(&j->lock);
mutex_unlock(&j->reclaim_lock);
return ret;
}
bool bch2_journal_flush_pins(struct journal *j, u64 seq_to_flush)
{
bool did_work = false;
if (!test_bit(JOURNAL_STARTED, &j->flags))
return false;
closure_wait_event(&j->async_wait,
journal_flush_done(j, seq_to_flush, &did_work));
return did_work;
}
int bch2_journal_flush_device_pins(struct journal *j, int dev_idx)
{
struct bch_fs *c = container_of(j, struct bch_fs, journal);
struct journal_entry_pin_list *p;
u64 iter, seq = 0;
int ret = 0;
spin_lock(&j->lock);
fifo_for_each_entry_ptr(p, &j->pin, iter)
if (dev_idx >= 0
? bch2_dev_list_has_dev(p->devs, dev_idx)
: p->devs.nr < c->opts.metadata_replicas)
seq = iter;
spin_unlock(&j->lock);
bch2_journal_flush_pins(j, seq);
ret = bch2_journal_error(j);
if (ret)
return ret;
mutex_lock(&c->replicas_gc_lock);
bch2_replicas_gc_start(c, 1 << BCH_DATA_journal);
seq = 0;
spin_lock(&j->lock);
while (!ret && seq < j->pin.back) {
struct bch_replicas_padded replicas;
seq = max(seq, journal_last_seq(j));
bch2_devlist_to_replicas(&replicas.e, BCH_DATA_journal,
journal_seq_pin(j, seq)->devs);
seq++;
spin_unlock(&j->lock);
ret = bch2_mark_replicas(c, &replicas.e);
spin_lock(&j->lock);
}
spin_unlock(&j->lock);
ret = bch2_replicas_gc_end(c, ret);
mutex_unlock(&c->replicas_gc_lock);
return ret;
}
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