linux/fs/bcachefs/journal.c
Uros Bizjak 68573b936d bcachefs: Use try_cmpxchg() family of functions instead of cmpxchg()
Use try_cmpxchg() family of functions instead of
cmpxchg (*ptr, old, new) == old. x86 CMPXCHG instruction returns
success in ZF flag, so this change saves a compare after cmpxchg
(and related move instruction in front of cmpxchg).

Also, try_cmpxchg() implicitly assigns old *ptr value to "old" when
cmpxchg fails. There is no need to re-read the value in the loop.

No functional change intended.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Brian Foster <bfoster@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-07-14 19:00:12 -04:00

1569 lines
39 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* bcachefs journalling code, for btree insertions
*
* Copyright 2012 Google, Inc.
*/
#include "bcachefs.h"
#include "alloc_foreground.h"
#include "bkey_methods.h"
#include "btree_gc.h"
#include "btree_update.h"
#include "btree_write_buffer.h"
#include "buckets.h"
#include "error.h"
#include "journal.h"
#include "journal_io.h"
#include "journal_reclaim.h"
#include "journal_sb.h"
#include "journal_seq_blacklist.h"
#include "trace.h"
static const char * const bch2_journal_errors[] = {
#define x(n) #n,
JOURNAL_ERRORS()
#undef x
NULL
};
static inline bool journal_seq_unwritten(struct journal *j, u64 seq)
{
return seq > j->seq_ondisk;
}
static bool __journal_entry_is_open(union journal_res_state state)
{
return state.cur_entry_offset < JOURNAL_ENTRY_CLOSED_VAL;
}
static inline unsigned nr_unwritten_journal_entries(struct journal *j)
{
return atomic64_read(&j->seq) - j->seq_ondisk;
}
static bool journal_entry_is_open(struct journal *j)
{
return __journal_entry_is_open(j->reservations);
}
static void bch2_journal_buf_to_text(struct printbuf *out, struct journal *j, u64 seq)
{
union journal_res_state s = READ_ONCE(j->reservations);
unsigned i = seq & JOURNAL_BUF_MASK;
struct journal_buf *buf = j->buf + i;
prt_printf(out, "seq:\t%llu\n", seq);
printbuf_indent_add(out, 2);
prt_printf(out, "refcount:\t%u\n", journal_state_count(s, i));
prt_printf(out, "size:\t");
prt_human_readable_u64(out, vstruct_bytes(buf->data));
prt_newline(out);
prt_printf(out, "expires:\t");
prt_printf(out, "%li jiffies\n", buf->expires - jiffies);
prt_printf(out, "flags:\t");
if (buf->noflush)
prt_str(out, "noflush ");
if (buf->must_flush)
prt_str(out, "must_flush ");
if (buf->separate_flush)
prt_str(out, "separate_flush ");
if (buf->need_flush_to_write_buffer)
prt_str(out, "need_flush_to_write_buffer ");
if (buf->write_started)
prt_str(out, "write_started ");
if (buf->write_allocated)
prt_str(out, "write_allocated ");
if (buf->write_done)
prt_str(out, "write_done");
prt_newline(out);
printbuf_indent_sub(out, 2);
}
static void bch2_journal_bufs_to_text(struct printbuf *out, struct journal *j)
{
if (!out->nr_tabstops)
printbuf_tabstop_push(out, 24);
for (u64 seq = journal_last_unwritten_seq(j);
seq <= journal_cur_seq(j);
seq++)
bch2_journal_buf_to_text(out, j, seq);
prt_printf(out, "last buf %s\n", journal_entry_is_open(j) ? "open" : "closed");
}
static inline struct journal_buf *
journal_seq_to_buf(struct journal *j, u64 seq)
{
struct journal_buf *buf = NULL;
EBUG_ON(seq > journal_cur_seq(j));
if (journal_seq_unwritten(j, seq)) {
buf = j->buf + (seq & JOURNAL_BUF_MASK);
EBUG_ON(le64_to_cpu(buf->data->seq) != seq);
}
return buf;
}
static void journal_pin_list_init(struct journal_entry_pin_list *p, int count)
{
unsigned i;
for (i = 0; i < ARRAY_SIZE(p->list); i++)
INIT_LIST_HEAD(&p->list[i]);
INIT_LIST_HEAD(&p->flushed);
atomic_set(&p->count, count);
p->devs.nr = 0;
}
/*
* Detect stuck journal conditions and trigger shutdown. Technically the journal
* can end up stuck for a variety of reasons, such as a blocked I/O, journal
* reservation lockup, etc. Since this is a fatal error with potentially
* unpredictable characteristics, we want to be fairly conservative before we
* decide to shut things down.
*
* Consider the journal stuck when it appears full with no ability to commit
* btree transactions, to discard journal buckets, nor acquire priority
* (reserved watermark) reservation.
*/
static inline bool
journal_error_check_stuck(struct journal *j, int error, unsigned flags)
{
struct bch_fs *c = container_of(j, struct bch_fs, journal);
bool stuck = false;
struct printbuf buf = PRINTBUF;
if (!(error == JOURNAL_ERR_journal_full ||
error == JOURNAL_ERR_journal_pin_full) ||
nr_unwritten_journal_entries(j) ||
(flags & BCH_WATERMARK_MASK) != BCH_WATERMARK_reclaim)
return stuck;
spin_lock(&j->lock);
if (j->can_discard) {
spin_unlock(&j->lock);
return stuck;
}
stuck = true;
/*
* The journal shutdown path will set ->err_seq, but do it here first to
* serialize against concurrent failures and avoid duplicate error
* reports.
*/
if (j->err_seq) {
spin_unlock(&j->lock);
return stuck;
}
j->err_seq = journal_cur_seq(j);
spin_unlock(&j->lock);
bch_err(c, "Journal stuck! Hava a pre-reservation but journal full (error %s)",
bch2_journal_errors[error]);
bch2_journal_debug_to_text(&buf, j);
bch_err(c, "%s", buf.buf);
printbuf_reset(&buf);
bch2_journal_pins_to_text(&buf, j);
bch_err(c, "Journal pins:\n%s", buf.buf);
printbuf_exit(&buf);
bch2_fatal_error(c);
dump_stack();
return stuck;
}
void bch2_journal_do_writes(struct journal *j)
{
for (u64 seq = journal_last_unwritten_seq(j);
seq <= journal_cur_seq(j);
seq++) {
unsigned idx = seq & JOURNAL_BUF_MASK;
struct journal_buf *w = j->buf + idx;
if (w->write_started && !w->write_allocated)
break;
if (w->write_started)
continue;
if (!journal_state_count(j->reservations, idx)) {
w->write_started = true;
closure_call(&w->io, bch2_journal_write, j->wq, NULL);
}
break;
}
}
/*
* Final processing when the last reference of a journal buffer has been
* dropped. Drop the pin list reference acquired at journal entry open and write
* the buffer, if requested.
*/
void bch2_journal_buf_put_final(struct journal *j, u64 seq)
{
lockdep_assert_held(&j->lock);
if (__bch2_journal_pin_put(j, seq))
bch2_journal_reclaim_fast(j);
bch2_journal_do_writes(j);
}
/*
* Returns true if journal entry is now closed:
*
* We don't close a journal_buf until the next journal_buf is finished writing,
* and can be opened again - this also initializes the next journal_buf:
*/
static void __journal_entry_close(struct journal *j, unsigned closed_val, bool trace)
{
struct bch_fs *c = container_of(j, struct bch_fs, journal);
struct journal_buf *buf = journal_cur_buf(j);
union journal_res_state old, new;
unsigned sectors;
BUG_ON(closed_val != JOURNAL_ENTRY_CLOSED_VAL &&
closed_val != JOURNAL_ENTRY_ERROR_VAL);
lockdep_assert_held(&j->lock);
old.v = atomic64_read(&j->reservations.counter);
do {
new.v = old.v;
new.cur_entry_offset = closed_val;
if (old.cur_entry_offset == JOURNAL_ENTRY_ERROR_VAL ||
old.cur_entry_offset == new.cur_entry_offset)
return;
} while (!atomic64_try_cmpxchg(&j->reservations.counter,
&old.v, new.v));
if (!__journal_entry_is_open(old))
return;
/* Close out old buffer: */
buf->data->u64s = cpu_to_le32(old.cur_entry_offset);
if (trace_journal_entry_close_enabled() && trace) {
struct printbuf pbuf = PRINTBUF;
pbuf.atomic++;
prt_str(&pbuf, "entry size: ");
prt_human_readable_u64(&pbuf, vstruct_bytes(buf->data));
prt_newline(&pbuf);
bch2_prt_task_backtrace(&pbuf, current, 1, GFP_NOWAIT);
trace_journal_entry_close(c, pbuf.buf);
printbuf_exit(&pbuf);
}
sectors = vstruct_blocks_plus(buf->data, c->block_bits,
buf->u64s_reserved) << c->block_bits;
BUG_ON(sectors > buf->sectors);
buf->sectors = sectors;
/*
* We have to set last_seq here, _before_ opening a new journal entry:
*
* A threads may replace an old pin with a new pin on their current
* journal reservation - the expectation being that the journal will
* contain either what the old pin protected or what the new pin
* protects.
*
* After the old pin is dropped journal_last_seq() won't include the old
* pin, so we can only write the updated last_seq on the entry that
* contains whatever the new pin protects.
*
* Restated, we can _not_ update last_seq for a given entry if there
* could be a newer entry open with reservations/pins that have been
* taken against it.
*
* Hence, we want update/set last_seq on the current journal entry right
* before we open a new one:
*/
buf->last_seq = journal_last_seq(j);
buf->data->last_seq = cpu_to_le64(buf->last_seq);
BUG_ON(buf->last_seq > le64_to_cpu(buf->data->seq));
cancel_delayed_work(&j->write_work);
bch2_journal_space_available(j);
__bch2_journal_buf_put(j, old.idx, le64_to_cpu(buf->data->seq));
}
void bch2_journal_halt(struct journal *j)
{
spin_lock(&j->lock);
__journal_entry_close(j, JOURNAL_ENTRY_ERROR_VAL, true);
if (!j->err_seq)
j->err_seq = journal_cur_seq(j);
journal_wake(j);
spin_unlock(&j->lock);
}
static bool journal_entry_want_write(struct journal *j)
{
bool ret = !journal_entry_is_open(j) ||
journal_cur_seq(j) == journal_last_unwritten_seq(j);
/* Don't close it yet if we already have a write in flight: */
if (ret)
__journal_entry_close(j, JOURNAL_ENTRY_CLOSED_VAL, true);
else if (nr_unwritten_journal_entries(j)) {
struct journal_buf *buf = journal_cur_buf(j);
if (!buf->flush_time) {
buf->flush_time = local_clock() ?: 1;
buf->expires = jiffies;
}
}
return ret;
}
bool bch2_journal_entry_close(struct journal *j)
{
bool ret;
spin_lock(&j->lock);
ret = journal_entry_want_write(j);
spin_unlock(&j->lock);
return ret;
}
/*
* should _only_ called from journal_res_get() - when we actually want a
* journal reservation - journal entry is open means journal is dirty:
*/
static int journal_entry_open(struct journal *j)
{
struct bch_fs *c = container_of(j, struct bch_fs, journal);
struct journal_buf *buf = j->buf +
((journal_cur_seq(j) + 1) & JOURNAL_BUF_MASK);
union journal_res_state old, new;
int u64s;
lockdep_assert_held(&j->lock);
BUG_ON(journal_entry_is_open(j));
BUG_ON(BCH_SB_CLEAN(c->disk_sb.sb));
if (j->blocked)
return JOURNAL_ERR_blocked;
if (j->cur_entry_error)
return j->cur_entry_error;
if (bch2_journal_error(j))
return JOURNAL_ERR_insufficient_devices; /* -EROFS */
if (!fifo_free(&j->pin))
return JOURNAL_ERR_journal_pin_full;
if (nr_unwritten_journal_entries(j) == ARRAY_SIZE(j->buf))
return JOURNAL_ERR_max_in_flight;
BUG_ON(!j->cur_entry_sectors);
buf->expires =
(journal_cur_seq(j) == j->flushed_seq_ondisk
? jiffies
: j->last_flush_write) +
msecs_to_jiffies(c->opts.journal_flush_delay);
buf->u64s_reserved = j->entry_u64s_reserved;
buf->disk_sectors = j->cur_entry_sectors;
buf->sectors = min(buf->disk_sectors, buf->buf_size >> 9);
u64s = (int) (buf->sectors << 9) / sizeof(u64) -
journal_entry_overhead(j);
u64s = clamp_t(int, u64s, 0, JOURNAL_ENTRY_CLOSED_VAL - 1);
if (u64s <= (ssize_t) j->early_journal_entries.nr)
return JOURNAL_ERR_journal_full;
if (fifo_empty(&j->pin) && j->reclaim_thread)
wake_up_process(j->reclaim_thread);
/*
* The fifo_push() needs to happen at the same time as j->seq is
* incremented for journal_last_seq() to be calculated correctly
*/
atomic64_inc(&j->seq);
journal_pin_list_init(fifo_push_ref(&j->pin), 1);
BUG_ON(j->pin.back - 1 != atomic64_read(&j->seq));
BUG_ON(j->buf + (journal_cur_seq(j) & JOURNAL_BUF_MASK) != buf);
bkey_extent_init(&buf->key);
buf->noflush = false;
buf->must_flush = false;
buf->separate_flush = false;
buf->flush_time = 0;
buf->need_flush_to_write_buffer = true;
buf->write_started = false;
buf->write_allocated = false;
buf->write_done = false;
memset(buf->data, 0, sizeof(*buf->data));
buf->data->seq = cpu_to_le64(journal_cur_seq(j));
buf->data->u64s = 0;
if (j->early_journal_entries.nr) {
memcpy(buf->data->_data, j->early_journal_entries.data,
j->early_journal_entries.nr * sizeof(u64));
le32_add_cpu(&buf->data->u64s, j->early_journal_entries.nr);
}
/*
* Must be set before marking the journal entry as open:
*/
j->cur_entry_u64s = u64s;
old.v = atomic64_read(&j->reservations.counter);
do {
new.v = old.v;
BUG_ON(old.cur_entry_offset == JOURNAL_ENTRY_ERROR_VAL);
new.idx++;
BUG_ON(journal_state_count(new, new.idx));
BUG_ON(new.idx != (journal_cur_seq(j) & JOURNAL_BUF_MASK));
journal_state_inc(&new);
/* Handle any already added entries */
new.cur_entry_offset = le32_to_cpu(buf->data->u64s);
} while (!atomic64_try_cmpxchg(&j->reservations.counter,
&old.v, new.v));
if (nr_unwritten_journal_entries(j) == 1)
mod_delayed_work(j->wq,
&j->write_work,
msecs_to_jiffies(c->opts.journal_flush_delay));
journal_wake(j);
if (j->early_journal_entries.nr)
darray_exit(&j->early_journal_entries);
return 0;
}
static bool journal_quiesced(struct journal *j)
{
bool ret = atomic64_read(&j->seq) == j->seq_ondisk;
if (!ret)
bch2_journal_entry_close(j);
return ret;
}
static void journal_quiesce(struct journal *j)
{
wait_event(j->wait, journal_quiesced(j));
}
static void journal_write_work(struct work_struct *work)
{
struct journal *j = container_of(work, struct journal, write_work.work);
spin_lock(&j->lock);
if (__journal_entry_is_open(j->reservations)) {
long delta = journal_cur_buf(j)->expires - jiffies;
if (delta > 0)
mod_delayed_work(j->wq, &j->write_work, delta);
else
__journal_entry_close(j, JOURNAL_ENTRY_CLOSED_VAL, true);
}
spin_unlock(&j->lock);
}
static int __journal_res_get(struct journal *j, struct journal_res *res,
unsigned flags)
{
struct bch_fs *c = container_of(j, struct bch_fs, journal);
struct journal_buf *buf;
bool can_discard;
int ret;
retry:
if (journal_res_get_fast(j, res, flags))
return 0;
if (bch2_journal_error(j))
return -BCH_ERR_erofs_journal_err;
if (j->blocked)
return -BCH_ERR_journal_res_get_blocked;
if ((flags & BCH_WATERMARK_MASK) < j->watermark) {
ret = JOURNAL_ERR_journal_full;
can_discard = j->can_discard;
goto out;
}
if (nr_unwritten_journal_entries(j) == ARRAY_SIZE(j->buf) && !journal_entry_is_open(j)) {
ret = JOURNAL_ERR_max_in_flight;
goto out;
}
spin_lock(&j->lock);
/*
* Recheck after taking the lock, so we don't race with another thread
* that just did journal_entry_open() and call bch2_journal_entry_close()
* unnecessarily
*/
if (journal_res_get_fast(j, res, flags)) {
ret = 0;
goto unlock;
}
/*
* If we couldn't get a reservation because the current buf filled up,
* and we had room for a bigger entry on disk, signal that we want to
* realloc the journal bufs:
*/
buf = journal_cur_buf(j);
if (journal_entry_is_open(j) &&
buf->buf_size >> 9 < buf->disk_sectors &&
buf->buf_size < JOURNAL_ENTRY_SIZE_MAX)
j->buf_size_want = max(j->buf_size_want, buf->buf_size << 1);
__journal_entry_close(j, JOURNAL_ENTRY_CLOSED_VAL, false);
ret = journal_entry_open(j) ?: JOURNAL_ERR_retry;
unlock:
can_discard = j->can_discard;
spin_unlock(&j->lock);
out:
if (ret == JOURNAL_ERR_retry)
goto retry;
if (!ret)
return 0;
if (journal_error_check_stuck(j, ret, flags))
ret = -BCH_ERR_journal_res_get_blocked;
if (ret == JOURNAL_ERR_max_in_flight &&
track_event_change(&c->times[BCH_TIME_blocked_journal_max_in_flight], true)) {
struct printbuf buf = PRINTBUF;
prt_printf(&buf, "seq %llu\n", journal_cur_seq(j));
bch2_journal_bufs_to_text(&buf, j);
trace_journal_entry_full(c, buf.buf);
printbuf_exit(&buf);
count_event(c, journal_entry_full);
}
/*
* Journal is full - can't rely on reclaim from work item due to
* freezing:
*/
if ((ret == JOURNAL_ERR_journal_full ||
ret == JOURNAL_ERR_journal_pin_full) &&
!(flags & JOURNAL_RES_GET_NONBLOCK)) {
if (can_discard) {
bch2_journal_do_discards(j);
goto retry;
}
if (mutex_trylock(&j->reclaim_lock)) {
bch2_journal_reclaim(j);
mutex_unlock(&j->reclaim_lock);
}
}
return ret == JOURNAL_ERR_insufficient_devices
? -BCH_ERR_erofs_journal_err
: -BCH_ERR_journal_res_get_blocked;
}
/*
* Essentially the entry function to the journaling code. When bcachefs is doing
* a btree insert, it calls this function to get the current journal write.
* Journal write is the structure used set up journal writes. The calling
* function will then add its keys to the structure, queuing them for the next
* write.
*
* To ensure forward progress, the current task must not be holding any
* btree node write locks.
*/
int bch2_journal_res_get_slowpath(struct journal *j, struct journal_res *res,
unsigned flags)
{
int ret;
closure_wait_event(&j->async_wait,
(ret = __journal_res_get(j, res, flags)) != -BCH_ERR_journal_res_get_blocked ||
(flags & JOURNAL_RES_GET_NONBLOCK));
return ret;
}
/* journal_entry_res: */
void bch2_journal_entry_res_resize(struct journal *j,
struct journal_entry_res *res,
unsigned new_u64s)
{
union journal_res_state state;
int d = new_u64s - res->u64s;
spin_lock(&j->lock);
j->entry_u64s_reserved += d;
if (d <= 0)
goto out;
j->cur_entry_u64s = max_t(int, 0, j->cur_entry_u64s - d);
smp_mb();
state = READ_ONCE(j->reservations);
if (state.cur_entry_offset < JOURNAL_ENTRY_CLOSED_VAL &&
state.cur_entry_offset > j->cur_entry_u64s) {
j->cur_entry_u64s += d;
/*
* Not enough room in current journal entry, have to flush it:
*/
__journal_entry_close(j, JOURNAL_ENTRY_CLOSED_VAL, true);
} else {
journal_cur_buf(j)->u64s_reserved += d;
}
out:
spin_unlock(&j->lock);
res->u64s += d;
}
/* journal flushing: */
/**
* bch2_journal_flush_seq_async - wait for a journal entry to be written
* @j: journal object
* @seq: seq to flush
* @parent: closure object to wait with
* Returns: 1 if @seq has already been flushed, 0 if @seq is being flushed,
* -EIO if @seq will never be flushed
*
* Like bch2_journal_wait_on_seq, except that it triggers a write immediately if
* necessary
*/
int bch2_journal_flush_seq_async(struct journal *j, u64 seq,
struct closure *parent)
{
struct journal_buf *buf;
int ret = 0;
if (seq <= j->flushed_seq_ondisk)
return 1;
spin_lock(&j->lock);
if (WARN_ONCE(seq > journal_cur_seq(j),
"requested to flush journal seq %llu, but currently at %llu",
seq, journal_cur_seq(j)))
goto out;
/* Recheck under lock: */
if (j->err_seq && seq >= j->err_seq) {
ret = -EIO;
goto out;
}
if (seq <= j->flushed_seq_ondisk) {
ret = 1;
goto out;
}
/* if seq was written, but not flushed - flush a newer one instead */
seq = max(seq, journal_last_unwritten_seq(j));
recheck_need_open:
if (seq > journal_cur_seq(j)) {
struct journal_res res = { 0 };
if (journal_entry_is_open(j))
__journal_entry_close(j, JOURNAL_ENTRY_CLOSED_VAL, true);
spin_unlock(&j->lock);
/*
* We're called from bch2_journal_flush_seq() -> wait_event();
* but this might block. We won't usually block, so we won't
* livelock:
*/
sched_annotate_sleep();
ret = bch2_journal_res_get(j, &res, jset_u64s(0), 0);
if (ret)
return ret;
seq = res.seq;
buf = journal_seq_to_buf(j, seq);
buf->must_flush = true;
if (!buf->flush_time) {
buf->flush_time = local_clock() ?: 1;
buf->expires = jiffies;
}
if (parent && !closure_wait(&buf->wait, parent))
BUG();
bch2_journal_res_put(j, &res);
spin_lock(&j->lock);
goto want_write;
}
/*
* if write was kicked off without a flush, or if we promised it
* wouldn't be a flush, flush the next sequence number instead
*/
buf = journal_seq_to_buf(j, seq);
if (buf->noflush) {
seq++;
goto recheck_need_open;
}
buf->must_flush = true;
if (parent && !closure_wait(&buf->wait, parent))
BUG();
want_write:
if (seq == journal_cur_seq(j))
journal_entry_want_write(j);
out:
spin_unlock(&j->lock);
return ret;
}
int bch2_journal_flush_seq(struct journal *j, u64 seq)
{
u64 start_time = local_clock();
int ret, ret2;
/*
* Don't update time_stats when @seq is already flushed:
*/
if (seq <= j->flushed_seq_ondisk)
return 0;
ret = wait_event_interruptible(j->wait, (ret2 = bch2_journal_flush_seq_async(j, seq, NULL)));
if (!ret)
bch2_time_stats_update(j->flush_seq_time, start_time);
return ret ?: ret2 < 0 ? ret2 : 0;
}
/*
* bch2_journal_flush_async - if there is an open journal entry, or a journal
* still being written, write it and wait for the write to complete
*/
void bch2_journal_flush_async(struct journal *j, struct closure *parent)
{
bch2_journal_flush_seq_async(j, atomic64_read(&j->seq), parent);
}
int bch2_journal_flush(struct journal *j)
{
return bch2_journal_flush_seq(j, atomic64_read(&j->seq));
}
/*
* bch2_journal_noflush_seq - tell the journal not to issue any flushes before
* @seq
*/
bool bch2_journal_noflush_seq(struct journal *j, u64 seq)
{
struct bch_fs *c = container_of(j, struct bch_fs, journal);
u64 unwritten_seq;
bool ret = false;
if (!(c->sb.features & (1ULL << BCH_FEATURE_journal_no_flush)))
return false;
if (seq <= c->journal.flushed_seq_ondisk)
return false;
spin_lock(&j->lock);
if (seq <= c->journal.flushed_seq_ondisk)
goto out;
for (unwritten_seq = journal_last_unwritten_seq(j);
unwritten_seq < seq;
unwritten_seq++) {
struct journal_buf *buf = journal_seq_to_buf(j, unwritten_seq);
/* journal flush already in flight, or flush requseted */
if (buf->must_flush)
goto out;
buf->noflush = true;
}
ret = true;
out:
spin_unlock(&j->lock);
return ret;
}
int bch2_journal_meta(struct journal *j)
{
struct journal_buf *buf;
struct journal_res res;
int ret;
memset(&res, 0, sizeof(res));
ret = bch2_journal_res_get(j, &res, jset_u64s(0), 0);
if (ret)
return ret;
buf = j->buf + (res.seq & JOURNAL_BUF_MASK);
buf->must_flush = true;
if (!buf->flush_time) {
buf->flush_time = local_clock() ?: 1;
buf->expires = jiffies;
}
bch2_journal_res_put(j, &res);
return bch2_journal_flush_seq(j, res.seq);
}
/* block/unlock the journal: */
void bch2_journal_unblock(struct journal *j)
{
spin_lock(&j->lock);
j->blocked--;
spin_unlock(&j->lock);
journal_wake(j);
}
void bch2_journal_block(struct journal *j)
{
spin_lock(&j->lock);
j->blocked++;
spin_unlock(&j->lock);
journal_quiesce(j);
}
static struct journal_buf *__bch2_next_write_buffer_flush_journal_buf(struct journal *j, u64 max_seq)
{
struct journal_buf *ret = NULL;
/* We're inside wait_event(), but using mutex_lock(: */
sched_annotate_sleep();
mutex_lock(&j->buf_lock);
spin_lock(&j->lock);
max_seq = min(max_seq, journal_cur_seq(j));
for (u64 seq = journal_last_unwritten_seq(j);
seq <= max_seq;
seq++) {
unsigned idx = seq & JOURNAL_BUF_MASK;
struct journal_buf *buf = j->buf + idx;
if (buf->need_flush_to_write_buffer) {
if (seq == journal_cur_seq(j))
__journal_entry_close(j, JOURNAL_ENTRY_CLOSED_VAL, true);
union journal_res_state s;
s.v = atomic64_read_acquire(&j->reservations.counter);
ret = journal_state_count(s, idx)
? ERR_PTR(-EAGAIN)
: buf;
break;
}
}
spin_unlock(&j->lock);
if (IS_ERR_OR_NULL(ret))
mutex_unlock(&j->buf_lock);
return ret;
}
struct journal_buf *bch2_next_write_buffer_flush_journal_buf(struct journal *j, u64 max_seq)
{
struct journal_buf *ret;
wait_event(j->wait, (ret = __bch2_next_write_buffer_flush_journal_buf(j, max_seq)) != ERR_PTR(-EAGAIN));
return ret;
}
/* allocate journal on a device: */
static int __bch2_set_nr_journal_buckets(struct bch_dev *ca, unsigned nr,
bool new_fs, struct closure *cl)
{
struct bch_fs *c = ca->fs;
struct journal_device *ja = &ca->journal;
u64 *new_bucket_seq = NULL, *new_buckets = NULL;
struct open_bucket **ob = NULL;
long *bu = NULL;
unsigned i, pos, nr_got = 0, nr_want = nr - ja->nr;
int ret = 0;
BUG_ON(nr <= ja->nr);
bu = kcalloc(nr_want, sizeof(*bu), GFP_KERNEL);
ob = kcalloc(nr_want, sizeof(*ob), GFP_KERNEL);
new_buckets = kcalloc(nr, sizeof(u64), GFP_KERNEL);
new_bucket_seq = kcalloc(nr, sizeof(u64), GFP_KERNEL);
if (!bu || !ob || !new_buckets || !new_bucket_seq) {
ret = -BCH_ERR_ENOMEM_set_nr_journal_buckets;
goto err_free;
}
for (nr_got = 0; nr_got < nr_want; nr_got++) {
if (new_fs) {
bu[nr_got] = bch2_bucket_alloc_new_fs(ca);
if (bu[nr_got] < 0) {
ret = -BCH_ERR_ENOSPC_bucket_alloc;
break;
}
} else {
ob[nr_got] = bch2_bucket_alloc(c, ca, BCH_WATERMARK_normal,
BCH_DATA_journal, cl);
ret = PTR_ERR_OR_ZERO(ob[nr_got]);
if (ret)
break;
ret = bch2_trans_run(c,
bch2_trans_mark_metadata_bucket(trans, ca,
ob[nr_got]->bucket, BCH_DATA_journal,
ca->mi.bucket_size, BTREE_TRIGGER_transactional));
if (ret) {
bch2_open_bucket_put(c, ob[nr_got]);
bch_err_msg(c, ret, "marking new journal buckets");
break;
}
bu[nr_got] = ob[nr_got]->bucket;
}
}
if (!nr_got)
goto err_free;
/* Don't return an error if we successfully allocated some buckets: */
ret = 0;
if (c) {
bch2_journal_flush_all_pins(&c->journal);
bch2_journal_block(&c->journal);
mutex_lock(&c->sb_lock);
}
memcpy(new_buckets, ja->buckets, ja->nr * sizeof(u64));
memcpy(new_bucket_seq, ja->bucket_seq, ja->nr * sizeof(u64));
BUG_ON(ja->discard_idx > ja->nr);
pos = ja->discard_idx ?: ja->nr;
memmove(new_buckets + pos + nr_got,
new_buckets + pos,
sizeof(new_buckets[0]) * (ja->nr - pos));
memmove(new_bucket_seq + pos + nr_got,
new_bucket_seq + pos,
sizeof(new_bucket_seq[0]) * (ja->nr - pos));
for (i = 0; i < nr_got; i++) {
new_buckets[pos + i] = bu[i];
new_bucket_seq[pos + i] = 0;
}
nr = ja->nr + nr_got;
ret = bch2_journal_buckets_to_sb(c, ca, new_buckets, nr);
if (ret)
goto err_unblock;
if (!new_fs)
bch2_write_super(c);
/* Commit: */
if (c)
spin_lock(&c->journal.lock);
swap(new_buckets, ja->buckets);
swap(new_bucket_seq, ja->bucket_seq);
ja->nr = nr;
if (pos <= ja->discard_idx)
ja->discard_idx = (ja->discard_idx + nr_got) % ja->nr;
if (pos <= ja->dirty_idx_ondisk)
ja->dirty_idx_ondisk = (ja->dirty_idx_ondisk + nr_got) % ja->nr;
if (pos <= ja->dirty_idx)
ja->dirty_idx = (ja->dirty_idx + nr_got) % ja->nr;
if (pos <= ja->cur_idx)
ja->cur_idx = (ja->cur_idx + nr_got) % ja->nr;
if (c)
spin_unlock(&c->journal.lock);
err_unblock:
if (c) {
bch2_journal_unblock(&c->journal);
mutex_unlock(&c->sb_lock);
}
if (ret && !new_fs)
for (i = 0; i < nr_got; i++)
bch2_trans_run(c,
bch2_trans_mark_metadata_bucket(trans, ca,
bu[i], BCH_DATA_free, 0,
BTREE_TRIGGER_transactional));
err_free:
if (!new_fs)
for (i = 0; i < nr_got; i++)
bch2_open_bucket_put(c, ob[i]);
kfree(new_bucket_seq);
kfree(new_buckets);
kfree(ob);
kfree(bu);
return ret;
}
/*
* Allocate more journal space at runtime - not currently making use if it, but
* the code works:
*/
int bch2_set_nr_journal_buckets(struct bch_fs *c, struct bch_dev *ca,
unsigned nr)
{
struct journal_device *ja = &ca->journal;
struct closure cl;
int ret = 0;
closure_init_stack(&cl);
down_write(&c->state_lock);
/* don't handle reducing nr of buckets yet: */
if (nr < ja->nr)
goto unlock;
while (ja->nr < nr) {
struct disk_reservation disk_res = { 0, 0, 0 };
/*
* note: journal buckets aren't really counted as _sectors_ used yet, so
* we don't need the disk reservation to avoid the BUG_ON() in buckets.c
* when space used goes up without a reservation - but we do need the
* reservation to ensure we'll actually be able to allocate:
*
* XXX: that's not right, disk reservations only ensure a
* filesystem-wide allocation will succeed, this is a device
* specific allocation - we can hang here:
*/
ret = bch2_disk_reservation_get(c, &disk_res,
bucket_to_sector(ca, nr - ja->nr), 1, 0);
if (ret)
break;
ret = __bch2_set_nr_journal_buckets(ca, nr, false, &cl);
bch2_disk_reservation_put(c, &disk_res);
closure_sync(&cl);
if (ret && ret != -BCH_ERR_bucket_alloc_blocked)
break;
}
bch_err_fn(c, ret);
unlock:
up_write(&c->state_lock);
return ret;
}
int bch2_dev_journal_alloc(struct bch_dev *ca, bool new_fs)
{
unsigned nr;
int ret;
if (dynamic_fault("bcachefs:add:journal_alloc")) {
ret = -BCH_ERR_ENOMEM_set_nr_journal_buckets;
goto err;
}
/* 1/128th of the device by default: */
nr = ca->mi.nbuckets >> 7;
/*
* clamp journal size to 8192 buckets or 8GB (in sectors), whichever
* is smaller:
*/
nr = clamp_t(unsigned, nr,
BCH_JOURNAL_BUCKETS_MIN,
min(1 << 13,
(1 << 24) / ca->mi.bucket_size));
ret = __bch2_set_nr_journal_buckets(ca, nr, new_fs, NULL);
err:
bch_err_fn(ca, ret);
return ret;
}
int bch2_fs_journal_alloc(struct bch_fs *c)
{
for_each_online_member(c, ca) {
if (ca->journal.nr)
continue;
int ret = bch2_dev_journal_alloc(ca, true);
if (ret) {
percpu_ref_put(&ca->io_ref);
return ret;
}
}
return 0;
}
/* startup/shutdown: */
static bool bch2_journal_writing_to_device(struct journal *j, unsigned dev_idx)
{
bool ret = false;
u64 seq;
spin_lock(&j->lock);
for (seq = journal_last_unwritten_seq(j);
seq <= journal_cur_seq(j) && !ret;
seq++) {
struct journal_buf *buf = journal_seq_to_buf(j, seq);
if (bch2_bkey_has_device_c(bkey_i_to_s_c(&buf->key), dev_idx))
ret = true;
}
spin_unlock(&j->lock);
return ret;
}
void bch2_dev_journal_stop(struct journal *j, struct bch_dev *ca)
{
wait_event(j->wait, !bch2_journal_writing_to_device(j, ca->dev_idx));
}
void bch2_fs_journal_stop(struct journal *j)
{
if (!test_bit(JOURNAL_running, &j->flags))
return;
bch2_journal_reclaim_stop(j);
bch2_journal_flush_all_pins(j);
wait_event(j->wait, bch2_journal_entry_close(j));
/*
* Always write a new journal entry, to make sure the clock hands are up
* to date (and match the superblock)
*/
bch2_journal_meta(j);
journal_quiesce(j);
cancel_delayed_work_sync(&j->write_work);
WARN(!bch2_journal_error(j) &&
test_bit(JOURNAL_replay_done, &j->flags) &&
j->last_empty_seq != journal_cur_seq(j),
"journal shutdown error: cur seq %llu but last empty seq %llu",
journal_cur_seq(j), j->last_empty_seq);
if (!bch2_journal_error(j))
clear_bit(JOURNAL_running, &j->flags);
}
int bch2_fs_journal_start(struct journal *j, u64 cur_seq)
{
struct bch_fs *c = container_of(j, struct bch_fs, journal);
struct journal_entry_pin_list *p;
struct journal_replay *i, **_i;
struct genradix_iter iter;
bool had_entries = false;
u64 last_seq = cur_seq, nr, seq;
genradix_for_each_reverse(&c->journal_entries, iter, _i) {
i = *_i;
if (journal_replay_ignore(i))
continue;
last_seq = le64_to_cpu(i->j.last_seq);
break;
}
nr = cur_seq - last_seq;
if (nr + 1 > j->pin.size) {
free_fifo(&j->pin);
init_fifo(&j->pin, roundup_pow_of_two(nr + 1), GFP_KERNEL);
if (!j->pin.data) {
bch_err(c, "error reallocating journal fifo (%llu open entries)", nr);
return -BCH_ERR_ENOMEM_journal_pin_fifo;
}
}
j->replay_journal_seq = last_seq;
j->replay_journal_seq_end = cur_seq;
j->last_seq_ondisk = last_seq;
j->flushed_seq_ondisk = cur_seq - 1;
j->seq_ondisk = cur_seq - 1;
j->pin.front = last_seq;
j->pin.back = cur_seq;
atomic64_set(&j->seq, cur_seq - 1);
fifo_for_each_entry_ptr(p, &j->pin, seq)
journal_pin_list_init(p, 1);
genradix_for_each(&c->journal_entries, iter, _i) {
i = *_i;
if (journal_replay_ignore(i))
continue;
seq = le64_to_cpu(i->j.seq);
BUG_ON(seq >= cur_seq);
if (seq < last_seq)
continue;
if (journal_entry_empty(&i->j))
j->last_empty_seq = le64_to_cpu(i->j.seq);
p = journal_seq_pin(j, seq);
p->devs.nr = 0;
darray_for_each(i->ptrs, ptr)
bch2_dev_list_add_dev(&p->devs, ptr->dev);
had_entries = true;
}
if (!had_entries)
j->last_empty_seq = cur_seq;
spin_lock(&j->lock);
set_bit(JOURNAL_running, &j->flags);
j->last_flush_write = jiffies;
j->reservations.idx = j->reservations.unwritten_idx = journal_cur_seq(j);
j->reservations.unwritten_idx++;
c->last_bucket_seq_cleanup = journal_cur_seq(j);
bch2_journal_space_available(j);
spin_unlock(&j->lock);
return bch2_journal_reclaim_start(j);
}
/* init/exit: */
void bch2_dev_journal_exit(struct bch_dev *ca)
{
struct journal_device *ja = &ca->journal;
for (unsigned i = 0; i < ARRAY_SIZE(ja->bio); i++) {
kfree(ja->bio[i]);
ja->bio[i] = NULL;
}
kfree(ja->buckets);
kfree(ja->bucket_seq);
ja->buckets = NULL;
ja->bucket_seq = NULL;
}
int bch2_dev_journal_init(struct bch_dev *ca, struct bch_sb *sb)
{
struct journal_device *ja = &ca->journal;
struct bch_sb_field_journal *journal_buckets =
bch2_sb_field_get(sb, journal);
struct bch_sb_field_journal_v2 *journal_buckets_v2 =
bch2_sb_field_get(sb, journal_v2);
ja->nr = 0;
if (journal_buckets_v2) {
unsigned nr = bch2_sb_field_journal_v2_nr_entries(journal_buckets_v2);
for (unsigned i = 0; i < nr; i++)
ja->nr += le64_to_cpu(journal_buckets_v2->d[i].nr);
} else if (journal_buckets) {
ja->nr = bch2_nr_journal_buckets(journal_buckets);
}
ja->bucket_seq = kcalloc(ja->nr, sizeof(u64), GFP_KERNEL);
if (!ja->bucket_seq)
return -BCH_ERR_ENOMEM_dev_journal_init;
unsigned nr_bvecs = DIV_ROUND_UP(JOURNAL_ENTRY_SIZE_MAX, PAGE_SIZE);
for (unsigned i = 0; i < ARRAY_SIZE(ja->bio); i++) {
ja->bio[i] = kmalloc(struct_size(ja->bio[i], bio.bi_inline_vecs,
nr_bvecs), GFP_KERNEL);
if (!ja->bio[i])
return -BCH_ERR_ENOMEM_dev_journal_init;
ja->bio[i]->ca = ca;
ja->bio[i]->buf_idx = i;
bio_init(&ja->bio[i]->bio, NULL, ja->bio[i]->bio.bi_inline_vecs, nr_bvecs, 0);
}
ja->buckets = kcalloc(ja->nr, sizeof(u64), GFP_KERNEL);
if (!ja->buckets)
return -BCH_ERR_ENOMEM_dev_journal_init;
if (journal_buckets_v2) {
unsigned nr = bch2_sb_field_journal_v2_nr_entries(journal_buckets_v2);
unsigned dst = 0;
for (unsigned i = 0; i < nr; i++)
for (unsigned j = 0; j < le64_to_cpu(journal_buckets_v2->d[i].nr); j++)
ja->buckets[dst++] =
le64_to_cpu(journal_buckets_v2->d[i].start) + j;
} else if (journal_buckets) {
for (unsigned i = 0; i < ja->nr; i++)
ja->buckets[i] = le64_to_cpu(journal_buckets->buckets[i]);
}
return 0;
}
void bch2_fs_journal_exit(struct journal *j)
{
if (j->wq)
destroy_workqueue(j->wq);
darray_exit(&j->early_journal_entries);
for (unsigned i = 0; i < ARRAY_SIZE(j->buf); i++)
kvfree(j->buf[i].data);
free_fifo(&j->pin);
}
int bch2_fs_journal_init(struct journal *j)
{
static struct lock_class_key res_key;
mutex_init(&j->buf_lock);
spin_lock_init(&j->lock);
spin_lock_init(&j->err_lock);
init_waitqueue_head(&j->wait);
INIT_DELAYED_WORK(&j->write_work, journal_write_work);
init_waitqueue_head(&j->reclaim_wait);
init_waitqueue_head(&j->pin_flush_wait);
mutex_init(&j->reclaim_lock);
mutex_init(&j->discard_lock);
lockdep_init_map(&j->res_map, "journal res", &res_key, 0);
atomic64_set(&j->reservations.counter,
((union journal_res_state)
{ .cur_entry_offset = JOURNAL_ENTRY_CLOSED_VAL }).v);
if (!(init_fifo(&j->pin, JOURNAL_PIN, GFP_KERNEL)))
return -BCH_ERR_ENOMEM_journal_pin_fifo;
for (unsigned i = 0; i < ARRAY_SIZE(j->buf); i++) {
j->buf[i].buf_size = JOURNAL_ENTRY_SIZE_MIN;
j->buf[i].data = kvmalloc(j->buf[i].buf_size, GFP_KERNEL);
if (!j->buf[i].data)
return -BCH_ERR_ENOMEM_journal_buf;
j->buf[i].idx = i;
}
j->pin.front = j->pin.back = 1;
j->wq = alloc_workqueue("bcachefs_journal",
WQ_HIGHPRI|WQ_FREEZABLE|WQ_UNBOUND|WQ_MEM_RECLAIM, 512);
if (!j->wq)
return -BCH_ERR_ENOMEM_fs_other_alloc;
return 0;
}
/* debug: */
static const char * const bch2_journal_flags_strs[] = {
#define x(n) #n,
JOURNAL_FLAGS()
#undef x
NULL
};
void __bch2_journal_debug_to_text(struct printbuf *out, struct journal *j)
{
struct bch_fs *c = container_of(j, struct bch_fs, journal);
union journal_res_state s;
unsigned long now = jiffies;
u64 nr_writes = j->nr_flush_writes + j->nr_noflush_writes;
printbuf_tabstops_reset(out);
printbuf_tabstop_push(out, 28);
out->atomic++;
rcu_read_lock();
s = READ_ONCE(j->reservations);
prt_printf(out, "flags:\t");
prt_bitflags(out, bch2_journal_flags_strs, j->flags);
prt_newline(out);
prt_printf(out, "dirty journal entries:\t%llu/%llu\n", fifo_used(&j->pin), j->pin.size);
prt_printf(out, "seq:\t%llu\n", journal_cur_seq(j));
prt_printf(out, "seq_ondisk:\t%llu\n", j->seq_ondisk);
prt_printf(out, "last_seq:\t%llu\n", journal_last_seq(j));
prt_printf(out, "last_seq_ondisk:\t%llu\n", j->last_seq_ondisk);
prt_printf(out, "flushed_seq_ondisk:\t%llu\n", j->flushed_seq_ondisk);
prt_printf(out, "watermark:\t%s\n", bch2_watermarks[j->watermark]);
prt_printf(out, "each entry reserved:\t%u\n", j->entry_u64s_reserved);
prt_printf(out, "nr flush writes:\t%llu\n", j->nr_flush_writes);
prt_printf(out, "nr noflush writes:\t%llu\n", j->nr_noflush_writes);
prt_printf(out, "average write size:\t");
prt_human_readable_u64(out, nr_writes ? div64_u64(j->entry_bytes_written, nr_writes) : 0);
prt_newline(out);
prt_printf(out, "nr direct reclaim:\t%llu\n", j->nr_direct_reclaim);
prt_printf(out, "nr background reclaim:\t%llu\n", j->nr_background_reclaim);
prt_printf(out, "reclaim kicked:\t%u\n", j->reclaim_kicked);
prt_printf(out, "reclaim runs in:\t%u ms\n", time_after(j->next_reclaim, now)
? jiffies_to_msecs(j->next_reclaim - jiffies) : 0);
prt_printf(out, "blocked:\t%u\n", j->blocked);
prt_printf(out, "current entry sectors:\t%u\n", j->cur_entry_sectors);
prt_printf(out, "current entry error:\t%s\n", bch2_journal_errors[j->cur_entry_error]);
prt_printf(out, "current entry:\t");
switch (s.cur_entry_offset) {
case JOURNAL_ENTRY_ERROR_VAL:
prt_printf(out, "error\n");
break;
case JOURNAL_ENTRY_CLOSED_VAL:
prt_printf(out, "closed\n");
break;
default:
prt_printf(out, "%u/%u\n", s.cur_entry_offset, j->cur_entry_u64s);
break;
}
prt_printf(out, "unwritten entries:\n");
bch2_journal_bufs_to_text(out, j);
prt_printf(out, "space:\n");
printbuf_indent_add(out, 2);
prt_printf(out, "discarded\t%u:%u\n",
j->space[journal_space_discarded].next_entry,
j->space[journal_space_discarded].total);
prt_printf(out, "clean ondisk\t%u:%u\n",
j->space[journal_space_clean_ondisk].next_entry,
j->space[journal_space_clean_ondisk].total);
prt_printf(out, "clean\t%u:%u\n",
j->space[journal_space_clean].next_entry,
j->space[journal_space_clean].total);
prt_printf(out, "total\t%u:%u\n",
j->space[journal_space_total].next_entry,
j->space[journal_space_total].total);
printbuf_indent_sub(out, 2);
for_each_member_device_rcu(c, ca, &c->rw_devs[BCH_DATA_journal]) {
struct journal_device *ja = &ca->journal;
if (!test_bit(ca->dev_idx, c->rw_devs[BCH_DATA_journal].d))
continue;
if (!ja->nr)
continue;
prt_printf(out, "dev %u:\n", ca->dev_idx);
printbuf_indent_add(out, 2);
prt_printf(out, "nr\t%u\n", ja->nr);
prt_printf(out, "bucket size\t%u\n", ca->mi.bucket_size);
prt_printf(out, "available\t%u:%u\n", bch2_journal_dev_buckets_available(j, ja, journal_space_discarded), ja->sectors_free);
prt_printf(out, "discard_idx\t%u\n", ja->discard_idx);
prt_printf(out, "dirty_ondisk\t%u (seq %llu)\n",ja->dirty_idx_ondisk, ja->bucket_seq[ja->dirty_idx_ondisk]);
prt_printf(out, "dirty_idx\t%u (seq %llu)\n", ja->dirty_idx, ja->bucket_seq[ja->dirty_idx]);
prt_printf(out, "cur_idx\t%u (seq %llu)\n", ja->cur_idx, ja->bucket_seq[ja->cur_idx]);
printbuf_indent_sub(out, 2);
}
rcu_read_unlock();
--out->atomic;
}
void bch2_journal_debug_to_text(struct printbuf *out, struct journal *j)
{
spin_lock(&j->lock);
__bch2_journal_debug_to_text(out, j);
spin_unlock(&j->lock);
}
bool bch2_journal_seq_pins_to_text(struct printbuf *out, struct journal *j, u64 *seq)
{
struct journal_entry_pin_list *pin_list;
struct journal_entry_pin *pin;
spin_lock(&j->lock);
if (!test_bit(JOURNAL_running, &j->flags)) {
spin_unlock(&j->lock);
return true;
}
*seq = max(*seq, j->pin.front);
if (*seq >= j->pin.back) {
spin_unlock(&j->lock);
return true;
}
out->atomic++;
pin_list = journal_seq_pin(j, *seq);
prt_printf(out, "%llu: count %u\n", *seq, atomic_read(&pin_list->count));
printbuf_indent_add(out, 2);
for (unsigned i = 0; i < ARRAY_SIZE(pin_list->list); i++)
list_for_each_entry(pin, &pin_list->list[i], list)
prt_printf(out, "\t%px %ps\n", pin, pin->flush);
if (!list_empty(&pin_list->flushed))
prt_printf(out, "flushed:\n");
list_for_each_entry(pin, &pin_list->flushed, list)
prt_printf(out, "\t%px %ps\n", pin, pin->flush);
printbuf_indent_sub(out, 2);
--out->atomic;
spin_unlock(&j->lock);
return false;
}
void bch2_journal_pins_to_text(struct printbuf *out, struct journal *j)
{
u64 seq = 0;
while (!bch2_journal_seq_pins_to_text(out, j, &seq))
seq++;
}