bcachefs: Increase journal pipelining

This patch increases the maximum journal buffers in flight from 2 to 4 -
this will be particularly helpful when in the future we stop requiring
flush+fua for every journal write.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/journal.c

@@ -23,7 +23,7 @@ static u64 last_unwritten_seq(struct journal *j)
 
 	lockdep_assert_held(&j->lock);
 
-	return journal_cur_seq(j) - s.prev_buf_unwritten;
+	return journal_cur_seq(j) - ((s.idx - s.unwritten_idx) & JOURNAL_BUF_MASK);
 }
 
 static inline bool journal_seq_unwritten(struct journal *j, u64 seq)
@@ -51,7 +51,7 @@ journal_seq_to_buf(struct journal *j, u64 seq)
 		j->reservations.cur_entry_offset == JOURNAL_ENTRY_CLOSED_VAL);
 
 	if (journal_seq_unwritten(j, seq)) {
-		buf = j->buf + (seq & 1);
+		buf = j->buf + (seq & JOURNAL_BUF_MASK);
 		EBUG_ON(le64_to_cpu(buf->data->seq) != seq);
 	}
 	return buf;
@@ -108,15 +108,8 @@ void bch2_journal_halt(struct journal *j)
 
 /* journal entry close/open: */
 
-void __bch2_journal_buf_put(struct journal *j, bool need_write_just_set)
+void __bch2_journal_buf_put(struct journal *j)
 {
-	if (!need_write_just_set &&
-	    test_bit(JOURNAL_NEED_WRITE, &j->flags))
-		bch2_time_stats_update(j->delay_time,
-				       j->need_write_time);
-
-	clear_bit(JOURNAL_NEED_WRITE, &j->flags);
-
 	closure_call(&j->io, bch2_journal_write, system_highpri_wq, NULL);
 }
 
@@ -129,7 +122,6 @@ static bool __journal_entry_close(struct journal *j)
 	struct journal_buf *buf = journal_cur_buf(j);
 	union journal_res_state old, new;
 	u64 v = atomic64_read(&j->reservations.counter);
-	bool set_need_write = false;
 	unsigned sectors;
 
 	lockdep_assert_held(&j->lock);
@@ -148,15 +140,13 @@ static bool __journal_entry_close(struct journal *j)
 		if (!test_bit(JOURNAL_NEED_WRITE, &j->flags)) {
 			set_bit(JOURNAL_NEED_WRITE, &j->flags);
 			j->need_write_time = local_clock();
-			set_need_write = true;
 		}
 
-		if (new.prev_buf_unwritten)
-			return false;
-
 		new.cur_entry_offset = JOURNAL_ENTRY_CLOSED_VAL;
 		new.idx++;
-		new.prev_buf_unwritten = 1;
+
+		if (new.idx == new.unwritten_idx)
+			return false;
 
 		BUG_ON(journal_state_count(new, new.idx));
 	} while ((v = atomic64_cmpxchg(&j->reservations.counter,
@@ -190,24 +180,44 @@ static bool __journal_entry_close(struct journal *j)
 	 */
 	buf->data->last_seq	= cpu_to_le64(journal_last_seq(j));
 
+	__bch2_journal_pin_put(j, le64_to_cpu(buf->data->seq));
+
 	journal_pin_new_entry(j, 1);
 
 	bch2_journal_buf_init(j);
 
 	cancel_delayed_work(&j->write_work);
+	clear_bit(JOURNAL_NEED_WRITE, &j->flags);
 
 	bch2_journal_space_available(j);
 
-	bch2_journal_buf_put(j, old.idx, set_need_write);
+	bch2_journal_buf_put(j, old.idx);
 	return true;
 }
 
+static bool journal_entry_want_write(struct journal *j)
+{
+	union journal_res_state s = READ_ONCE(j->reservations);
+	bool ret = false;
+
+	/*
+	 * Don't close it yet if we already have a write in flight, but do set
+	 * NEED_WRITE:
+	 */
+	if (s.idx != s.unwritten_idx)
+		set_bit(JOURNAL_NEED_WRITE, &j->flags);
+	else
+		ret = __journal_entry_close(j);
+
+	return ret;
+}
+
 static bool journal_entry_close(struct journal *j)
 {
 	bool ret;
 
 	spin_lock(&j->lock);
-	ret = __journal_entry_close(j);
+	ret = journal_entry_want_write(j);
 	spin_unlock(&j->lock);
 
 	return ret;
@@ -289,8 +299,8 @@ static int journal_entry_open(struct journal *j)
 
 static bool journal_quiesced(struct journal *j)
 {
-	union journal_res_state state = READ_ONCE(j->reservations);
-	bool ret = !state.prev_buf_unwritten && !__journal_entry_is_open(state);
+	union journal_res_state s = READ_ONCE(j->reservations);
+	bool ret = s.idx == s.unwritten_idx && !__journal_entry_is_open(s);
 
 	if (!ret)
 		journal_entry_close(j);
@@ -317,17 +327,29 @@ static void journal_write_work(struct work_struct *work)
 u64 bch2_inode_journal_seq(struct journal *j, u64 inode)
 {
 	size_t h = hash_64(inode, ilog2(sizeof(j->buf[0].has_inode) * 8));
-	u64 seq = 0;
+	union journal_res_state s;
+	unsigned i;
+	u64 seq;
 
-	if (!test_bit(h, j->buf[0].has_inode) &&
-	    !test_bit(h, j->buf[1].has_inode))
-		return 0;
 
 	spin_lock(&j->lock);
-	if (test_bit(h, journal_cur_buf(j)->has_inode))
 	seq = journal_cur_seq(j);
-	else if (test_bit(h, journal_prev_buf(j)->has_inode))
-		seq = journal_cur_seq(j) - 1;
+	s = READ_ONCE(j->reservations);
+	i = s.idx;
+
+	while (1) {
+		if (test_bit(h, j->buf[i].has_inode))
+			goto out;
+
+		if (i == s.unwritten_idx)
+			break;
+
+		i = (i - 1) & JOURNAL_BUF_MASK;
+		seq--;
+	}
+
+	seq = 0;
+out:
 	spin_unlock(&j->lock);
 
 	return seq;
@@ -574,7 +596,7 @@ int bch2_journal_flush_seq_async(struct journal *j, u64 seq,
 			BUG();
 
 	if (seq == journal_cur_seq(j))
-		__journal_entry_close(j);
+		journal_entry_want_write(j);
 out:
 	spin_unlock(&j->lock);
 	return ret;
@@ -863,15 +885,18 @@ int bch2_dev_journal_alloc(struct bch_dev *ca)
 static bool bch2_journal_writing_to_device(struct journal *j, unsigned dev_idx)
 {
 	union journal_res_state state;
-	struct journal_buf *w;
-	bool ret;
+	bool ret = false;
+	unsigned i;
 
 	spin_lock(&j->lock);
 	state = READ_ONCE(j->reservations);
-	w = j->buf + !state.idx;
+	i = state.idx;
 
-	ret = state.prev_buf_unwritten &&
-		bch2_bkey_has_device(bkey_i_to_s_c(&w->key), dev_idx);
+	while (i != state.unwritten_idx) {
+		i = (i - 1) & JOURNAL_BUF_MASK;
+		if (bch2_bkey_has_device(bkey_i_to_s_c(&j->buf[i].key), dev_idx))
+			ret = true;
+	}
 	spin_unlock(&j->lock);
 
 	return ret;
@@ -957,7 +982,7 @@ int bch2_fs_journal_start(struct journal *j, u64 cur_seq,
 
 	journal_pin_new_entry(j, 1);
 
-	j->reservations.idx = journal_cur_seq(j);
+	j->reservations.idx = j->reservations.unwritten_idx = journal_cur_seq(j);
 
 	bch2_journal_buf_init(j);
 
@@ -1015,8 +1040,10 @@ int bch2_dev_journal_init(struct bch_dev *ca, struct bch_sb *sb)
 
 void bch2_fs_journal_exit(struct journal *j)
 {
-	kvpfree(j->buf[1].data, j->buf[1].buf_size);
-	kvpfree(j->buf[0].data, j->buf[0].buf_size);
+	unsigned i;
+
+	for (i = 0; i < ARRAY_SIZE(j->buf); i++)
+		kvpfree(j->buf[i].data, j->buf[i].buf_size);
 	free_fifo(&j->pin);
 }
 
@@ -1024,6 +1051,7 @@ int bch2_fs_journal_init(struct journal *j)
 {
 	struct bch_fs *c = container_of(j, struct bch_fs, journal);
 	static struct lock_class_key res_key;
+	unsigned i;
 	int ret = 0;
 
 	pr_verbose_init(c->opts, "");
@@ -1038,8 +1066,6 @@ int bch2_fs_journal_init(struct journal *j)
 
 	lockdep_init_map(&j->res_map, "journal res", &res_key, 0);
 
-	j->buf[0].buf_size	= JOURNAL_ENTRY_SIZE_MIN;
-	j->buf[1].buf_size	= JOURNAL_ENTRY_SIZE_MIN;
 	j->write_delay_ms	= 1000;
 	j->reclaim_delay_ms	= 100;
 
@@ -1051,13 +1077,20 @@ int bch2_fs_journal_init(struct journal *j)
 		((union journal_res_state)
 		 { .cur_entry_offset = JOURNAL_ENTRY_CLOSED_VAL }).v);
 
-	if (!(init_fifo(&j->pin, JOURNAL_PIN, GFP_KERNEL)) ||
-	    !(j->buf[0].data = kvpmalloc(j->buf[0].buf_size, GFP_KERNEL)) ||
-	    !(j->buf[1].data = kvpmalloc(j->buf[1].buf_size, GFP_KERNEL))) {
+	if (!(init_fifo(&j->pin, JOURNAL_PIN, GFP_KERNEL))) {
 		ret = -ENOMEM;
 		goto out;
 	}
 
+	for (i = 0; i < ARRAY_SIZE(j->buf); i++) {
+		j->buf[i].buf_size = JOURNAL_ENTRY_SIZE_MIN;
+		j->buf[i].data = kvpmalloc(j->buf[i].buf_size, GFP_KERNEL);
+		if (!j->buf[i].data) {
+			ret = -ENOMEM;
+			goto out;
+		}
+	}
+
 	j->pin.front = j->pin.back = 1;
 out:
 	pr_verbose_init(c->opts, "ret %i", ret);
@@ -1071,7 +1104,7 @@ 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;
 	struct bch_dev *ca;
-	unsigned iter;
+	unsigned i;
 
 	rcu_read_lock();
 	spin_lock(&j->lock);
@@ -1114,16 +1147,16 @@ void bch2_journal_debug_to_text(struct printbuf *out, struct journal *j)
 	}
 
 	pr_buf(out,
-	       "current entry refs:\t%u\n"
-	       "prev entry unwritten:\t",
-	       journal_state_count(s, s.idx));
-
-	if (s.prev_buf_unwritten)
-		pr_buf(out, "yes, ref %u sectors %u\n",
-		       journal_state_count(s, !s.idx),
-		       journal_prev_buf(j)->sectors);
-	else
-		pr_buf(out, "no\n");
+	       "current entry:\tidx %u refcount %u\n",
+	       s.idx, journal_state_count(s, s.idx));
+
+	i = s.idx;
+	while (i != s.unwritten_idx) {
+		i = (i - 1) & JOURNAL_BUF_MASK;
+
+		pr_buf(out, "unwritten entry:\tidx %u refcount %u sectors %u\n",
+		       i, journal_state_count(s, i), j->buf[i].sectors);
+	}
 
 	pr_buf(out,
 	       "need write:\t\t%i\n"
@@ -1131,7 +1164,7 @@ void bch2_journal_debug_to_text(struct printbuf *out, struct journal *j)
 	       test_bit(JOURNAL_NEED_WRITE,	&j->flags),
 	       test_bit(JOURNAL_REPLAY_DONE,	&j->flags));
 
-	for_each_member_device_rcu(ca, c, iter,
+	for_each_member_device_rcu(ca, c, i,
 				   &c->rw_devs[BCH_DATA_journal]) {
 		struct journal_device *ja = &ca->journal;
 
@@ -1146,7 +1179,7 @@ void bch2_journal_debug_to_text(struct printbuf *out, struct journal *j)
 		       "\tdirty_idx_ondisk\t%u (seq %llu)\n"
 		       "\tdirty_idx\t\t%u (seq %llu)\n"
 		       "\tcur_idx\t\t%u (seq %llu)\n",
-		       iter, ja->nr,
+		       i, ja->nr,
 		       bch2_journal_dev_buckets_available(j, ja, journal_space_discarded),
 		       ja->sectors_free,
 		       ja->discard_idx,

fs/bcachefs/journal.h

@@ -127,11 +127,6 @@ static inline struct journal_buf *journal_cur_buf(struct journal *j)
 	return j->buf + j->reservations.idx;
 }
 
-static inline struct journal_buf *journal_prev_buf(struct journal *j)
-{
-	return j->buf + !j->reservations.idx;
-}
-
 /* Sequence number of oldest dirty journal entry */
 
 static inline u64 journal_last_seq(struct journal *j)
@@ -151,13 +146,21 @@ void bch2_journal_set_has_inum(struct journal *, u64, u64);
 
 static inline int journal_state_count(union journal_res_state s, int idx)
 {
-	return idx == 0 ? s.buf0_count : s.buf1_count;
+	switch (idx) {
+	case 0: return s.buf0_count;
+	case 1: return s.buf1_count;
+	case 2: return s.buf2_count;
+	case 3: return s.buf3_count;
+	}
+	BUG();
 }
 
 static inline void journal_state_inc(union journal_res_state *s)
 {
 	s->buf0_count += s->idx == 0;
 	s->buf1_count += s->idx == 1;
+	s->buf2_count += s->idx == 2;
+	s->buf3_count += s->idx == 3;
 }
 
 static inline void bch2_journal_set_has_inode(struct journal *j,
@@ -257,21 +260,24 @@ static inline bool journal_entry_empty(struct jset *j)
 	return true;
 }
 
-void __bch2_journal_buf_put(struct journal *, bool);
+void __bch2_journal_buf_put(struct journal *);
 
-static inline void bch2_journal_buf_put(struct journal *j, unsigned idx,
-				       bool need_write_just_set)
+static inline void bch2_journal_buf_put(struct journal *j, unsigned idx)
 {
 	union journal_res_state s;
 
 	s.v = atomic64_sub_return(((union journal_res_state) {
 				    .buf0_count = idx == 0,
 				    .buf1_count = idx == 1,
+				    .buf2_count = idx == 2,
+				    .buf3_count = idx == 3,
 				    }).v, &j->reservations.counter);
-	if (!journal_state_count(s, idx)) {
-		EBUG_ON(s.idx == idx || !s.prev_buf_unwritten);
-		__bch2_journal_buf_put(j, need_write_just_set);
-	}
+
+	EBUG_ON(((s.idx - idx) & 3) >
+		((s.idx - s.unwritten_idx) & 3));
+
+	if (!journal_state_count(s, idx) && idx == s.unwritten_idx)
+		__bch2_journal_buf_put(j);
 }
 
 /*
@@ -291,7 +297,7 @@ static inline void bch2_journal_res_put(struct journal *j,
 				       BCH_JSET_ENTRY_btree_keys,
 				       0, 0, NULL, 0);
 
-	bch2_journal_buf_put(j, res->idx, false);
+	bch2_journal_buf_put(j, res->idx);
 
 	res->ref = 0;
 }
@@ -327,11 +333,18 @@ static inline int journal_res_get_fast(struct journal *j,
 		    !test_bit(JOURNAL_MAY_GET_UNRESERVED, &j->flags))
 			return 0;
 
-		if (flags & JOURNAL_RES_GET_CHECK)
-			return 1;
-
 		new.cur_entry_offset += res->u64s;
 		journal_state_inc(&new);
+
+		/*
+		 * If the refcount would overflow, we have to wait:
+		 * XXX - tracepoint this:
+		 */
+		if (!journal_state_count(new, new.idx))
+			return 0;
+
+		if (flags & JOURNAL_RES_GET_CHECK)
+			return 1;
 	} while ((v = atomic64_cmpxchg(&j->reservations.counter,
 				       old.v, new.v)) != old.v);
 

fs/bcachefs/journal_io.c

@@ -950,16 +950,23 @@ static void journal_buf_realloc(struct journal *j, struct journal_buf *buf)
 	buf->buf_size	= new_size;
 }
 
+static inline struct journal_buf *journal_last_unwritten_buf(struct journal *j)
+{
+	return j->buf + j->reservations.unwritten_idx;
+}
+
 static void journal_write_done(struct closure *cl)
 {
 	struct journal *j = container_of(cl, struct journal, io);
 	struct bch_fs *c = container_of(j, struct bch_fs, journal);
-	struct journal_buf *w = journal_prev_buf(j);
+	struct journal_buf *w = journal_last_unwritten_buf(j);
 	struct bch_devs_list devs =
 		bch2_bkey_devs(bkey_i_to_s_c(&w->key));
 	struct bch_replicas_padded replicas;
+	union journal_res_state old, new;
 	u64 seq = le64_to_cpu(w->data->seq);
 	u64 last_seq = le64_to_cpu(w->data->last_seq);
+	u64 v;
 	int err = 0;
 
 	bch2_time_stats_update(j->write_time, j->write_start_time);
@@ -998,9 +1005,14 @@ static void journal_write_done(struct closure *cl)
 	/* also must come before signalling write completion: */
 	closure_debug_destroy(cl);
 
-	BUG_ON(!j->reservations.prev_buf_unwritten);
-	atomic64_sub(((union journal_res_state) { .prev_buf_unwritten = 1 }).v,
-		     &j->reservations.counter);
+	v = atomic64_read(&j->reservations.counter);
+	do {
+		old.v = new.v = v;
+		BUG_ON(new.idx == new.unwritten_idx);
+
+		new.unwritten_idx++;
+	} while ((v = atomic64_cmpxchg(&j->reservations.counter,
+				       old.v, new.v)) != old.v);
 
 	closure_wake_up(&w->wait);
 	journal_wake(j);
@@ -1008,6 +1020,10 @@ static void journal_write_done(struct closure *cl)
 	if (test_bit(JOURNAL_NEED_WRITE, &j->flags))
 		mod_delayed_work(system_freezable_wq, &j->write_work, 0);
 	spin_unlock(&j->lock);
+
+	if (new.unwritten_idx != new.idx &&
+	    !journal_state_count(new, new.unwritten_idx))
+		closure_call(&j->io, bch2_journal_write, system_highpri_wq, NULL);
 }
 
 static void journal_write_endio(struct bio *bio)
@@ -1018,7 +1034,7 @@ static void journal_write_endio(struct bio *bio)
 	if (bch2_dev_io_err_on(bio->bi_status, ca, "journal write error: %s",
 			       bch2_blk_status_to_str(bio->bi_status)) ||
 	    bch2_meta_write_fault("journal")) {
-		struct journal_buf *w = journal_prev_buf(j);
+		struct journal_buf *w = journal_last_unwritten_buf(j);
 		unsigned long flags;
 
 		spin_lock_irqsave(&j->err_lock, flags);
@@ -1035,7 +1051,7 @@ void bch2_journal_write(struct closure *cl)
 	struct journal *j = container_of(cl, struct journal, io);
 	struct bch_fs *c = container_of(j, struct bch_fs, journal);
 	struct bch_dev *ca;
-	struct journal_buf *w = journal_prev_buf(j);
+	struct journal_buf *w = journal_last_unwritten_buf(j);
 	struct jset_entry *start, *end;
 	struct jset *jset;
 	struct bio *bio;
@@ -1046,8 +1062,6 @@ void bch2_journal_write(struct closure *cl)
 
 	BUG_ON(BCH_SB_CLEAN(c->disk_sb.sb));
 
-	bch2_journal_pin_put(j, le64_to_cpu(w->data->seq));
-
 	journal_buf_realloc(j, w);
 	jset = w->data;
 

fs/bcachefs/journal_reclaim.c

@@ -58,6 +58,19 @@ static void journal_set_remaining(struct journal *j, unsigned u64s_remaining)
 				       old.v, new.v)) != old.v);
 }
 
+static inline unsigned get_unwritten_sectors(struct journal *j, unsigned *idx)
+{
+	unsigned sectors = 0;
+
+	while (!sectors && *idx != j->reservations.idx) {
+		sectors = j->buf[*idx].sectors;
+
+		*idx = (*idx + 1) & JOURNAL_BUF_MASK;
+	}
+
+	return sectors;
+}
+
 static struct journal_space {
 	unsigned	next_entry;
 	unsigned	remaining;
@@ -69,15 +82,14 @@ static struct journal_space {
 	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;
+	unsigned unwritten_sectors;
 
 	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;
+		unsigned idx = j->reservations.unwritten_idx;
 
 		if (!ja->nr)
 			continue;
@@ -89,15 +101,19 @@ static struct journal_space {
 		 * We that we don't allocate the space for a journal entry
 		 * until we write it out - thus, account for it here:
 		 */
+		while ((unwritten_sectors = get_unwritten_sectors(j, &idx))) {
 			if (unwritten_sectors >= sectors_this_device) {
-			if (!buckets_this_device)
-				continue;
+				if (!buckets_this_device) {
+					sectors_this_device = 0;
+					break;
+				}
 
 				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) {
@@ -277,6 +293,14 @@ static void bch2_journal_reclaim_fast(struct journal *j)
 		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);

fs/bcachefs/journal_reclaim.h

@@ -39,6 +39,7 @@ journal_seq_pin(struct journal *j, u64 seq)
 	return &j->pin.data[seq & j->pin.mask];
 }
 
+void __bch2_journal_pin_put(struct journal *, u64);
 void bch2_journal_pin_put(struct journal *, u64);
 void bch2_journal_pin_drop(struct journal *, struct journal_entry_pin *);
 

fs/bcachefs/journal_types.h

@@ -11,13 +11,13 @@
 
 struct journal_res;
 
-#define JOURNAL_BUF_BITS	1
+#define JOURNAL_BUF_BITS	2
 #define JOURNAL_BUF_NR		(1U << JOURNAL_BUF_BITS)
 #define JOURNAL_BUF_MASK	(JOURNAL_BUF_NR - 1)
 
 /*
- * We put two of these in struct journal; we used them for writes to the
- * journal that are being staged or in flight.
+ * We put JOURNAL_BUF_NR of these in struct journal; we used them for writes to
+ * the journal that are being staged or in flight.
  */
 struct journal_buf {
 	struct jset		*data;
@@ -85,10 +85,12 @@ union journal_res_state {
 
 	struct {
 		u64		cur_entry_offset:20,
-				idx:1,
-				prev_buf_unwritten:1,
-				buf0_count:21,
-				buf1_count:21;
+				idx:2,
+				unwritten_idx:2,
+				buf0_count:10,
+				buf1_count:10,
+				buf2_count:10,
+				buf3_count:10;
 	};
 };
 
@@ -169,7 +171,7 @@ struct journal {
 	 * Two journal entries -- one is currently open for new entries, the
 	 * other is possibly being written out.
 	 */
-	struct journal_buf	buf[2];
+	struct journal_buf	buf[JOURNAL_BUF_NR];
 
 	spinlock_t		lock;
 

fs/bcachefs/recovery.c

@@ -1048,13 +1048,13 @@ int bch2_fs_recovery(struct bch_fs *c)
 	if (!c->sb.clean) {
 		ret = bch2_journal_seq_blacklist_add(c,
 						     journal_seq,
-						     journal_seq + 4);
+						     journal_seq + 8);
 		if (ret) {
 			bch_err(c, "error creating new journal seq blacklist entry");
 			goto err;
 		}
 
-		journal_seq += 4;
+		journal_seq += 8;
 
 		/*
 		 * The superblock needs to be written before we do any btree