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|
// SPDX-License-Identifier: GPL-2.0
#include "bcachefs.h"
#include "btree_key_cache.h"
#include "btree_update.h"
#include "errcode.h"
#include "error.h"
#include "journal.h"
#include "journal_io.h"
#include "journal_reclaim.h"
#include "replicas.h"
#include "super.h"
#include "trace.h"
#include <linux/kthread.h>
#include <linux/sched/mm.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
journal_dev_space_available(struct journal *j, struct bch_dev *ca,
enum journal_space_from from)
{
struct journal_device *ja = &ca->journal;
unsigned sectors, buckets, unwritten;
u64 seq;
if (from == journal_space_total)
return (struct journal_space) {
.next_entry = ca->mi.bucket_size,
.total = ca->mi.bucket_size * ja->nr,
};
buckets = bch2_journal_dev_buckets_available(j, ja, from);
sectors = 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:
*/
for (seq = journal_last_unwritten_seq(j);
seq <= journal_cur_seq(j);
seq++) {
unwritten = j->buf[seq & JOURNAL_BUF_MASK].sectors;
if (!unwritten)
continue;
/* entry won't fit on this device, skip: */
if (unwritten > ca->mi.bucket_size)
continue;
if (unwritten >= sectors) {
if (!buckets) {
sectors = 0;
break;
}
buckets--;
sectors = ca->mi.bucket_size;
}
sectors -= unwritten;
}
if (sectors < ca->mi.bucket_size && buckets) {
buckets--;
sectors = ca->mi.bucket_size;
}
return (struct journal_space) {
.next_entry = sectors,
.total = sectors + buckets * ca->mi.bucket_size,
};
}
static struct journal_space __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 i, pos, nr_devs = 0;
struct journal_space space, dev_space[BCH_SB_MEMBERS_MAX];
BUG_ON(nr_devs_want > ARRAY_SIZE(dev_space));
rcu_read_lock();
for_each_member_device_rcu(ca, c, i,
&c->rw_devs[BCH_DATA_journal]) {
if (!ca->journal.nr)
continue;
space = journal_dev_space_available(j, ca, from);
if (!space.next_entry)
continue;
for (pos = 0; pos < nr_devs; pos++)
if (space.total > dev_space[pos].total)
break;
array_insert_item(dev_space, nr_devs, pos, space);
}
rcu_read_unlock();
if (nr_devs < nr_devs_want)
return (struct journal_space) { 0, 0 };
/*
* We sorted largest to smallest, and we want the smallest out of the
* @nr_devs_want largest devices:
*/
return dev_space[nr_devs_want - 1];
}
void bch2_journal_space_available(struct journal *j)
{
struct bch_fs *c = container_of(j, struct bch_fs, journal);
struct bch_dev *ca;
unsigned clean, clean_ondisk, total;
s64 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 = JOURNAL_ERR_insufficient_devices;
goto out;
}
nr_devs_want = min_t(unsigned, nr_online, c->opts.metadata_replicas);
for (i = 0; i < journal_space_nr; i++)
j->space[i] = __journal_space_available(j, nr_devs_want, i);
clean_ondisk = j->space[journal_space_clean_ondisk].total;
clean = j->space[journal_space_clean].total;
total = j->space[journal_space_total].total;
if (!j->space[journal_space_discarded].next_entry)
ret = JOURNAL_ERR_journal_full;
if ((j->space[journal_space_clean_ondisk].next_entry <
j->space[journal_space_clean_ondisk].total) &&
(clean - clean_ondisk <= total / 8) &&
(clean_ondisk * 2 > clean))
set_bit(JOURNAL_MAY_SKIP_FLUSH, &j->flags);
else
clear_bit(JOURNAL_MAY_SKIP_FLUSH, &j->flags);
u64s_remaining = (u64) clean << 6;
u64s_remaining -= (u64) total << 3;
u64s_remaining = max(0LL, u64s_remaining);
u64s_remaining /= 4;
u64s_remaining = min_t(u64, u64s_remaining, U32_MAX);
out:
j->cur_entry_sectors = !ret ? j->space[journal_space_discarded].next_entry : 0;
j->cur_entry_error = ret;
journal_set_remaining(j, u64s_remaining);
journal_set_watermark(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 (!c->opts.nochanges &&
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)) {
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))
bch2_journal_reclaim_fast(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 bool __journal_pin_drop(struct journal *j,
struct journal_entry_pin *pin)
{
struct journal_entry_pin_list *pin_list;
if (!journal_pin_active(pin))
return false;
if (j->flush_in_progress == pin)
j->flush_in_progress_dropped = true;
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:
*/
return atomic_dec_and_test(&pin_list->count) &&
pin_list == &fifo_peek_front(&j->pin);
}
void bch2_journal_pin_drop(struct journal *j,
struct journal_entry_pin *pin)
{
spin_lock(&j->lock);
if (__journal_pin_drop(j, pin))
bch2_journal_reclaim_fast(j);
spin_unlock(&j->lock);
}
enum journal_pin_type journal_pin_type(journal_pin_flush_fn fn)
{
if (fn == bch2_btree_node_flush0 ||
fn == bch2_btree_node_flush1)
return JOURNAL_PIN_btree;
else if (fn == bch2_btree_key_cache_journal_flush)
return JOURNAL_PIN_key_cache;
else
return JOURNAL_PIN_other;
}
void bch2_journal_pin_set(struct journal *j, u64 seq,
struct journal_entry_pin *pin,
journal_pin_flush_fn flush_fn)
{
struct journal_entry_pin_list *pin_list;
bool reclaim;
spin_lock(&j->lock);
if (seq < journal_last_seq(j)) {
/*
* bch2_journal_pin_copy() raced with bch2_journal_pin_drop() on
* the src pin - with the pin dropped, the entry to pin might no
* longer to exist, but that means there's no longer anything to
* copy and we can bail out here:
*/
spin_unlock(&j->lock);
return;
}
pin_list = journal_seq_pin(j, seq);
reclaim = __journal_pin_drop(j, pin);
atomic_inc(&pin_list->count);
pin->seq = seq;
pin->flush = flush_fn;
if (flush_fn)
list_add(&pin->list, &pin_list->list[journal_pin_type(flush_fn)]);
else
list_add(&pin->list, &pin_list->flushed);
if (reclaim)
bch2_journal_reclaim_fast(j);
spin_unlock(&j->lock);
/*
* If the journal is currently full, we might want to call flush_fn
* immediately:
*/
journal_wake(j);
}
/**
* 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 seq_to_flush,
unsigned allowed_below_seq,
unsigned allowed_above_seq,
u64 *seq)
{
struct journal_entry_pin_list *pin_list;
struct journal_entry_pin *ret = NULL;
unsigned i;
fifo_for_each_entry_ptr(pin_list, &j->pin, *seq) {
if (*seq > seq_to_flush && !allowed_above_seq)
break;
for (i = 0; i < JOURNAL_PIN_NR; i++)
if ((((1U << i) & allowed_below_seq) && *seq <= seq_to_flush) ||
((1U << i) & allowed_above_seq)) {
ret = list_first_entry_or_null(&pin_list->list[i],
struct journal_entry_pin, list);
if (ret)
return ret;
}
}
return NULL;
}
/* returns true if we did work */
static size_t journal_flush_pins(struct journal *j,
u64 seq_to_flush,
unsigned allowed_below_seq,
unsigned allowed_above_seq,
unsigned min_any,
unsigned min_key_cache)
{
struct journal_entry_pin *pin;
size_t nr_flushed = 0;
journal_pin_flush_fn flush_fn;
u64 seq;
int err;
lockdep_assert_held(&j->reclaim_lock);
while (1) {
unsigned allowed_above = allowed_above_seq;
unsigned allowed_below = allowed_below_seq;
if (min_any) {
allowed_above |= ~0;
allowed_below |= ~0;
}
if (min_key_cache) {
allowed_above |= 1U << JOURNAL_PIN_key_cache;
allowed_below |= 1U << JOURNAL_PIN_key_cache;
}
cond_resched();
j->last_flushed = jiffies;
spin_lock(&j->lock);
pin = journal_get_next_pin(j, seq_to_flush, allowed_below, allowed_above, &seq);
if (pin) {
BUG_ON(j->flush_in_progress);
j->flush_in_progress = pin;
j->flush_in_progress_dropped = false;
flush_fn = pin->flush;
}
spin_unlock(&j->lock);
if (!pin)
break;
if (min_key_cache && pin->flush == bch2_btree_key_cache_journal_flush)
min_key_cache--;
if (min_any)
min_any--;
err = flush_fn(j, pin, seq);
spin_lock(&j->lock);
/* Pin might have been dropped or rearmed: */
if (likely(!err && !j->flush_in_progress_dropped))
list_move(&pin->list, &journal_seq_pin(j, seq)->flushed);
j->flush_in_progress = NULL;
j->flush_in_progress_dropped = false;
spin_unlock(&j->lock);
wake_up(&j->pin_flush_wait);
if (err)
break;
nr_flushed++;
}
return nr_flushed;
}
static u64 journal_seq_to_flush(struct journal *j)
{
struct bch_fs *c = container_of(j, struct bch_fs, journal);
struct bch_dev *ca;
u64 seq_to_flush = 0;
unsigned iter;
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);
return seq_to_flush;
}
/**
* 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.
*/
static int __bch2_journal_reclaim(struct journal *j, bool direct, bool kicked)
{
struct bch_fs *c = container_of(j, struct bch_fs, journal);
bool kthread = (current->flags & PF_KTHREAD) != 0;
u64 seq_to_flush;
size_t min_nr, min_key_cache, nr_flushed;
unsigned flags;
int ret = 0;
/*
* We can't invoke memory reclaim while holding the reclaim_lock -
* journal reclaim is required to make progress for memory reclaim
* (cleaning the caches), so we can't get stuck in memory reclaim while
* we're holding the reclaim lock:
*/
lockdep_assert_held(&j->reclaim_lock);
flags = memalloc_noreclaim_save();
do {
if (kthread && kthread_should_stop())
break;
if (bch2_journal_error(j)) {
ret = -EIO;
break;
}
bch2_journal_do_discards(j);
seq_to_flush = journal_seq_to_flush(j);
min_nr = 0;
/*
* 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(c->opts.journal_reclaim_delay)))
min_nr = 1;
if (j->prereserved.reserved * 4 > j->prereserved.remaining)
min_nr = 1;
if (fifo_free(&j->pin) <= 32)
min_nr = 1;
if (atomic_read(&c->btree_cache.dirty) * 2 > c->btree_cache.used)
min_nr = 1;
min_key_cache = min(bch2_nr_btree_keys_need_flush(c), (size_t) 128);
trace_and_count(c, journal_reclaim_start, c,
direct, kicked,
min_nr, min_key_cache,
j->prereserved.reserved,
j->prereserved.remaining,
atomic_read(&c->btree_cache.dirty),
c->btree_cache.used,
atomic_long_read(&c->btree_key_cache.nr_dirty),
atomic_long_read(&c->btree_key_cache.nr_keys));
nr_flushed = journal_flush_pins(j, seq_to_flush,
~0, 0,
min_nr, min_key_cache);
if (direct)
j->nr_direct_reclaim += nr_flushed;
else
j->nr_background_reclaim += nr_flushed;
trace_and_count(c, journal_reclaim_finish, c, nr_flushed);
if (nr_flushed)
wake_up(&j->reclaim_wait);
} while ((min_nr || min_key_cache) && nr_flushed && !direct);
memalloc_noreclaim_restore(flags);
return ret;
}
int bch2_journal_reclaim(struct journal *j)
{
return __bch2_journal_reclaim(j, true, true);
}
static int bch2_journal_reclaim_thread(void *arg)
{
struct journal *j = arg;
struct bch_fs *c = container_of(j, struct bch_fs, journal);
unsigned long delay, now;
bool journal_empty;
int ret = 0;
set_freezable();
j->last_flushed = jiffies;
while (!ret && !kthread_should_stop()) {
bool kicked = j->reclaim_kicked;
j->reclaim_kicked = false;
mutex_lock(&j->reclaim_lock);
ret = __bch2_journal_reclaim(j, false, kicked);
mutex_unlock(&j->reclaim_lock);
now = jiffies;
delay = msecs_to_jiffies(c->opts.journal_reclaim_delay);
j->next_reclaim = j->last_flushed + delay;
if (!time_in_range(j->next_reclaim, now, now + delay))
j->next_reclaim = now + delay;
while (1) {
set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE);
if (kthread_should_stop())
break;
if (j->reclaim_kicked)
break;
spin_lock(&j->lock);
journal_empty = fifo_empty(&j->pin);
spin_unlock(&j->lock);
if (journal_empty)
schedule();
else if (time_after(j->next_reclaim, jiffies))
schedule_timeout(j->next_reclaim - jiffies);
else
break;
}
__set_current_state(TASK_RUNNING);
}
return 0;
}
void bch2_journal_reclaim_stop(struct journal *j)
{
struct task_struct *p = j->reclaim_thread;
j->reclaim_thread = NULL;
if (p) {
kthread_stop(p);
put_task_struct(p);
}
}
int bch2_journal_reclaim_start(struct journal *j)
{
struct bch_fs *c = container_of(j, struct bch_fs, journal);
struct task_struct *p;
int ret;
if (j->reclaim_thread)
return 0;
p = kthread_create(bch2_journal_reclaim_thread, j,
"bch-reclaim/%s", c->name);
ret = PTR_ERR_OR_ZERO(p);
if (ret) {
bch_err(c, "error creating journal reclaim thread: %s", bch2_err_str(ret));
return ret;
}
get_task_struct(p);
j->reclaim_thread = p;
wake_up_process(p);
return 0;
}
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);
if (journal_flush_pins(j, seq_to_flush,
(1U << JOURNAL_PIN_key_cache)|
(1U << JOURNAL_PIN_other), 0, 0, 0) ||
journal_flush_pins(j, seq_to_flush,
(1U << JOURNAL_PIN_btree), 0, 0, 0))
*did_work = true;
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);
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) {
struct bch_replicas_padded replicas;
seq = max(seq, journal_last_seq(j));
if (seq >= j->pin.back)
break;
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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