bcachefs: Journal reclaim refactoring

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

6 files changed, 290 insertions, 278 deletions

diff --git a/fs/bcachefs/journal.c b/fs/bcachefs/journal.c
index c9881fc2df17..9b6f7b4136d8 100644
--- a/fs/bcachefs/journal.c
+++ b/fs/bcachefs/journal.c
@@ -84,17 +84,12 @@ void bch2_journal_halt(struct journal *j)
 
 	journal_wake(j);
 	closure_wake_up(&journal_cur_buf(j)->wait);
-	closure_wake_up(&journal_prev_buf(j)->wait);
 }
 
 /* journal entry close/open: */
 
 void __bch2_journal_buf_put(struct journal *j, bool need_write_just_set)
 {
-	struct journal_buf *w = journal_prev_buf(j);
-
-	atomic_dec_bug(&journal_seq_pin(j, le64_to_cpu(w->data->seq))->count);
-
 	if (!need_write_just_set &&
 	    test_bit(JOURNAL_NEED_WRITE, &j->flags))
 		bch2_time_stats_update(j->delay_time,
@@ -175,7 +170,6 @@ static bool __journal_entry_close(struct journal *j)
 	 * Hence, we want update/set last_seq on the current journal entry right
 	 * before we open a new one:
 	 */
-	bch2_journal_reclaim_fast(j);
 	buf->data->last_seq	= cpu_to_le64(journal_last_seq(j));
 
 	if (journal_entry_empty(buf->data))
@@ -189,8 +183,8 @@ static bool __journal_entry_close(struct journal *j)
 
 	cancel_delayed_work(&j->write_work);
 
-	/* ugh - might be called from __journal_res_get() under wait_event() */
-	__set_current_state(TASK_RUNNING);
+	bch2_journal_space_available(j);
+
 	bch2_journal_buf_put(j, old.idx, set_need_write);
 	return true;
 }
@@ -220,7 +214,7 @@ static int journal_entry_open(struct journal *j)
 {
 	struct journal_buf *buf = journal_cur_buf(j);
 	union journal_res_state old, new;
-	int u64s, ret;
+	int u64s;
 	u64 v;
 
 	lockdep_assert_held(&j->lock);
@@ -229,12 +223,10 @@ static int journal_entry_open(struct journal *j)
 	if (j->blocked)
 		return -EAGAIN;
 
-	if (!fifo_free(&j->pin))
-		return -ENOSPC;
+	if (j->cur_entry_error)
+		return j->cur_entry_error;
 
-	ret = bch2_journal_space_available(j);
-	if (ret)
-		return ret;
+	BUG_ON(!j->cur_entry_sectors);
 
 	buf->u64s_reserved	= j->entry_u64s_reserved;
 	buf->disk_sectors	= j->cur_entry_sectors;
@@ -411,7 +403,7 @@ int bch2_journal_res_get_slowpath(struct journal *j, struct journal_res *res,
 {
 	int ret;
 
-	wait_event(j->wait,
+	closure_wait_event(&j->async_wait,
 		   (ret = __journal_res_get(j, res, flags)) != -EAGAIN ||
 		   (flags & JOURNAL_RES_GET_NONBLOCK));
 	return ret;
@@ -969,6 +961,7 @@ void bch2_fs_journal_start(struct journal *j)
 
 	c->last_bucket_seq_cleanup = journal_cur_seq(j);
 
+	bch2_journal_space_available(j);
 	spin_unlock(&j->lock);
 
 	/*
@@ -1144,9 +1137,12 @@ ssize_t bch2_journal_print_debug(struct journal *j, char *buf)
 		pr_buf(&out,
 		       "dev %u:\n"
 		       "\tnr\t\t%u\n"
+		       "\tavailable\t%u:%u\n"
 		       "\tcur_idx\t\t%u (seq %llu)\n"
 		       "\tlast_idx\t%u (seq %llu)\n",
 		       iter, ja->nr,
+		       bch2_journal_dev_buckets_available(j, ja),
+		       ja->sectors_free,
 		       ja->cur_idx,	ja->bucket_seq[ja->cur_idx],
 		       ja->last_idx,	ja->bucket_seq[ja->last_idx]);
 	}
diff --git a/fs/bcachefs/journal_io.c b/fs/bcachefs/journal_io.c
index 1f7bd314f61e..e4466816fafa 100644
--- a/fs/bcachefs/journal_io.c
+++ b/fs/bcachefs/journal_io.c
@@ -825,7 +825,6 @@ fsck_err:
 int bch2_journal_replay(struct bch_fs *c, struct list_head *list)
 {
 	struct journal *j = &c->journal;
-	struct journal_entry_pin_list *pin_list;
 	struct bkey_i *k, *_n;
 	struct jset_entry *entry;
 	struct journal_replay *i, *n;
@@ -867,10 +866,7 @@ int bch2_journal_replay(struct bch_fs *c, struct list_head *list)
 			cond_resched();
 		}
 
-		pin_list = journal_seq_pin(j, j->replay_journal_seq);
-
-		if (atomic_dec_and_test(&pin_list->count))
-			journal_wake(j);
+		bch2_journal_pin_put(j, j->replay_journal_seq);
 	}
 
 	j->replay_journal_seq = 0;
@@ -885,101 +881,6 @@ err:
 
 /* journal write: */
 
-static unsigned journal_dev_buckets_available(struct journal *j,
-					      struct journal_device *ja)
-{
-	struct bch_fs *c = container_of(j, struct bch_fs, journal);
-	unsigned next = (ja->cur_idx + 1) % ja->nr;
-	unsigned available = (ja->last_idx + ja->nr - next) % ja->nr;
-
-	/*
-	 * Allocator startup needs some journal space before we can do journal
-	 * replay:
-	 */
-	if (available &&
-	    test_bit(BCH_FS_ALLOCATOR_STARTED, &c->flags))
-		available--;
-
-	/*
-	 * Don't use the last bucket unless writing the new last_seq
-	 * will make another bucket available:
-	 */
-	if (available &&
-	    journal_last_seq(j) <= ja->bucket_seq[ja->last_idx])
-		--available;
-
-	return available;
-}
-
-int bch2_journal_space_available(struct journal *j)
-{
-	struct bch_fs *c = container_of(j, struct bch_fs, journal);
-	struct bch_dev *ca;
-	unsigned sectors_next_entry	= UINT_MAX;
-	unsigned i, nr_online = 0, nr_devs = 0;
-	unsigned unwritten_sectors = j->reservations.prev_buf_unwritten
-		? journal_prev_buf(j)->sectors
-		: 0;
-	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;
-		unsigned buckets_this_device, sectors_this_device;
-
-		if (!ja->nr)
-			continue;
-
-		nr_online++;
-
-		buckets_this_device = journal_dev_buckets_available(j, ja);
-		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 (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);
-
-		nr_devs++;
-	}
-	rcu_read_unlock();
-
-	if (nr_online < c->opts.metadata_replicas_required) {
-		ret = -EROFS;
-		sectors_next_entry = 0;
-	} else if (!sectors_next_entry ||
-		   nr_devs < min_t(unsigned, nr_online,
-				   c->opts.metadata_replicas)) {
-		ret = -ENOSPC;
-		sectors_next_entry = 0;
-	}
-
-	WRITE_ONCE(j->cur_entry_sectors, sectors_next_entry);
-
-	return ret;
-}
-
 static void __journal_write_alloc(struct journal *j,
 				  struct journal_buf *w,
 				  struct dev_alloc_list *devs_sorted,
@@ -1053,7 +954,6 @@ static int journal_write_alloc(struct journal *j, struct journal_buf *w,
 	devs_sorted = bch2_dev_alloc_list(c, &j->wp.stripe,
 					  &c->rw_devs[BCH_DATA_JOURNAL]);
 
-	spin_lock(&j->lock);
 	__journal_write_alloc(j, w, &devs_sorted,
 			      sectors, &replicas, replicas_want);
 
@@ -1069,7 +969,7 @@ static int journal_write_alloc(struct journal *j, struct journal_buf *w,
 
 		if (sectors > ja->sectors_free &&
 		    sectors <= ca->mi.bucket_size &&
-		    journal_dev_buckets_available(j, ja)) {
+		    bch2_journal_dev_buckets_available(j, ja)) {
 			ja->cur_idx = (ja->cur_idx + 1) % ja->nr;
 			ja->sectors_free = ca->mi.bucket_size;
 		}
@@ -1078,7 +978,6 @@ static int journal_write_alloc(struct journal *j, struct journal_buf *w,
 	__journal_write_alloc(j, w, &devs_sorted,
 			      sectors, &replicas, replicas_want);
 done:
-	spin_unlock(&j->lock);
 	rcu_read_unlock();
 
 	return replicas >= c->opts.metadata_replicas_required ? 0 : -EROFS;
@@ -1237,6 +1136,9 @@ void bch2_journal_write(struct closure *cl)
 	struct bch_extent_ptr *ptr;
 	bool validate_before_checksum = false;
 	unsigned i, sectors, bytes, u64s;
+	int ret;
+
+	bch2_journal_pin_put(j, le64_to_cpu(w->data->seq));
 
 	journal_buf_realloc(j, w);
 	jset = w->data;
@@ -1293,7 +1195,23 @@ void bch2_journal_write(struct closure *cl)
 	bytes = vstruct_bytes(jset);
 	memset((void *) jset + bytes, 0, (sectors << 9) - bytes);
 
-	if (journal_write_alloc(j, w, sectors)) {
+	spin_lock(&j->lock);
+	ret = journal_write_alloc(j, w, sectors);
+
+	/*
+	 * write is allocated, no longer need to account for it in
+	 * bch2_journal_space_available():
+	 */
+	w->sectors = 0;
+
+	/*
+	 * journal entry has been compacted and allocated, recalculate space
+	 * available:
+	 */
+	bch2_journal_space_available(j);
+	spin_unlock(&j->lock);
+
+	if (ret) {
 		bch2_journal_halt(j);
 		bch_err(c, "Unable to allocate journal write");
 		bch2_fatal_error(c);
@@ -1302,12 +1220,6 @@ void bch2_journal_write(struct closure *cl)
 	}
 
 	/*
-	 * write is allocated, no longer need to account for it in
-	 * bch2_journal_entry_sectors:
-	 */
-	w->sectors = 0;
-
-	/*
 	 * XXX: we really should just disable the entire journal in nochanges
 	 * mode
 	 */
diff --git a/fs/bcachefs/journal_io.h b/fs/bcachefs/journal_io.h
index d1409039724d..a79c396903f0 100644
--- a/fs/bcachefs/journal_io.h
+++ b/fs/bcachefs/journal_io.h
@@ -40,7 +40,6 @@ int bch2_journal_read(struct bch_fs *, struct list_head *);
 void bch2_journal_entries_free(struct list_head *);
 int bch2_journal_replay(struct bch_fs *, struct list_head *);
 
-int bch2_journal_space_available(struct journal *);
 void bch2_journal_write(struct closure *);
 
 #endif /* _BCACHEFS_JOURNAL_IO_H */
diff --git a/fs/bcachefs/journal_reclaim.c b/fs/bcachefs/journal_reclaim.c
index 98345dcd1e67..3b5b646859cb 100644
--- a/fs/bcachefs/journal_reclaim.c
+++ b/fs/bcachefs/journal_reclaim.c
@@ -2,15 +2,213 @@
 
 #include "bcachefs.h"
 #include "journal.h"
+#include "journal_io.h"
 #include "journal_reclaim.h"
 #include "replicas.h"
 #include "super.h"
 
+/* Free space calculations: */
+
+unsigned bch2_journal_dev_buckets_available(struct journal *j,
+					    struct journal_device *ja)
+{
+	struct bch_fs *c = container_of(j, struct bch_fs, journal);
+	unsigned next = (ja->cur_idx + 1) % ja->nr;
+	unsigned available = (ja->last_idx + ja->nr - next) % ja->nr;
+
+	/*
+	 * Allocator startup needs some journal space before we can do journal
+	 * replay:
+	 */
+	if (available &&
+	    test_bit(BCH_FS_ALLOCATOR_STARTED, &c->flags))
+		available--;
+
+	/*
+	 * Don't use the last bucket unless writing the new last_seq
+	 * will make another bucket available:
+	 */
+	if (available &&
+	    journal_last_seq(j) <= ja->bucket_seq[ja->last_idx])
+		--available;
+
+	return available;
+}
+
+void bch2_journal_space_available(struct journal *j)
+{
+	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 max_entry_size		= min(j->buf[0].buf_size >> 9,
+					      j->buf[1].buf_size >> 9);
+	unsigned i, nr_online = 0, nr_devs = 0;
+	unsigned unwritten_sectors = j->reservations.prev_buf_unwritten
+		? journal_prev_buf(j)->sectors
+		: 0;
+	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;
+		unsigned buckets_this_device, sectors_this_device;
+
+		if (!ja->nr)
+			continue;
+
+		nr_online++;
+
+		buckets_this_device = bch2_journal_dev_buckets_available(j, ja);
+		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);
+
+		max_entry_size = min_t(unsigned, max_entry_size,
+				       ca->mi.bucket_size);
+
+		nr_devs++;
+	}
+	rcu_read_unlock();
+
+	if (nr_online < c->opts.metadata_replicas_required) {
+		ret = -EROFS;
+		sectors_next_entry = 0;
+	} else if (!sectors_next_entry ||
+		   nr_devs < min_t(unsigned, nr_online,
+				   c->opts.metadata_replicas)) {
+		ret = -ENOSPC;
+		sectors_next_entry = 0;
+	} else if (!fifo_free(&j->pin)) {
+		ret = -ENOSPC;
+		sectors_next_entry = 0;
+	}
+
+	j->cur_entry_sectors	= sectors_next_entry;
+	j->cur_entry_error	= ret;
+
+	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->nr &&
+		ja->last_idx != ja->cur_idx &&
+		ja->bucket_seq[ja->last_idx] < j->last_seq_ondisk;
+	spin_unlock(&j->lock);
+
+	return ret;
+}
+
+/*
+ * Advance ja->last_idx as long as it points to buckets that are no longer
+ * dirty, issuing discards if necessary:
+ */
+static void 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->reclaim_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->last_idx]),
+					ca->mi.bucket_size, GFP_NOIO);
+
+			spin_lock(&j->lock);
+			ja->last_idx = (ja->last_idx + 1) % ja->nr;
+
+			bch2_journal_space_available(j);
+			spin_unlock(&j->lock);
+		}
+	}
+
+	mutex_unlock(&j->reclaim_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_add(struct journal *j,
 				     u64 seq,
 				     struct journal_entry_pin *pin,
@@ -25,10 +223,7 @@ static inline void __journal_pin_add(struct journal *j,
 	pin->seq	= seq;
 	pin->flush	= flush_fn;
 
-	if (flush_fn)
-		list_add(&pin->list, &pin_list->list);
-	else
-		INIT_LIST_HEAD(&pin->list);
+	list_add(&pin->list, flush_fn ? &pin_list->list : &pin_list->flushed);
 
 	/*
 	 * If the journal is currently full,  we might want to call flush_fn
@@ -130,86 +325,53 @@ void bch2_journal_pin_flush(struct journal *j, struct journal_entry_pin *pin)
  * data off of a specific device:
  */
 
-/**
- * bch2_journal_reclaim_fast - do the fast part of journal reclaim
- *
- * Called from IO submission context, does not block. Cleans up after btree
- * write completions by advancing the journal pin and each cache's last_idx,
- * kicking off discards and background reclaim as necessary.
- */
-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)
-		journal_wake(j);
-}
-
-static void journal_pin_mark_flushing(struct journal *j,
-				      struct journal_entry_pin *pin,
-				      u64 seq)
-{
-	lockdep_assert_held(&j->reclaim_lock);
-
-	list_move(&pin->list, &journal_seq_pin(j, seq)->flushed);
-	BUG_ON(j->flush_in_progress);
-	j->flush_in_progress = pin;
-}
-
-static void journal_pin_flush(struct journal *j,
-			      struct journal_entry_pin *pin,
-			      u64 seq)
-{
-	pin->flush(j, pin, seq);
-
-	BUG_ON(j->flush_in_progress != pin);
-	j->flush_in_progress = NULL;
-	wake_up(&j->pin_flush_wait);
-}
-
 static struct journal_entry_pin *
-journal_get_next_pin(struct journal *j, u64 seq_to_flush, u64 *seq)
+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;
 
-	/* no need to iterate over empty fifo entries: */
-	bch2_journal_reclaim_fast(j);
+	spin_lock(&j->lock);
+
+	BUG_ON(!atomic_read(&fifo_peek_front(&j->pin).count));
 
 	fifo_for_each_entry_ptr(pin_list, &j->pin, *seq)
-		if (*seq > seq_to_flush ||
+		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;
 }
 
-static bool should_discard_bucket(struct journal *j, struct journal_device *ja)
+static void journal_flush_pins(struct journal *j, u64 seq_to_flush,
+			       unsigned min_nr)
 {
-	bool ret;
+	struct journal_entry_pin *pin;
+	u64 seq;
 
-	spin_lock(&j->lock);
-	ret = ja->nr &&
-		(ja->last_idx != ja->cur_idx &&
-		 ja->bucket_seq[ja->last_idx] < j->last_seq_ondisk);
-	spin_unlock(&j->lock);
+	lockdep_assert_held(&j->reclaim_lock);
 
-	return ret;
+	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);
+	}
 }
 
 /**
@@ -236,104 +398,44 @@ void bch2_journal_reclaim_work(struct work_struct *work)
 				struct bch_fs, journal.reclaim_work);
 	struct journal *j = &c->journal;
 	struct bch_dev *ca;
-	struct journal_entry_pin *pin;
-	u64 seq, seq_to_flush = 0;
-	unsigned iter, bucket_to_flush;
-	unsigned long next_flush;
-	bool reclaim_lock_held = false, need_flush;
+	unsigned iter, bucket_to_flush, min_nr = 0;
+	u64 seq_to_flush = 0;
+
+	journal_do_discards(j);
+
+	mutex_lock(&j->reclaim_lock);
+	spin_lock(&j->lock);
 
-	/*
-	 * Advance last_idx to point to the oldest journal entry containing
-	 * btree node updates that have not yet been written out
-	 */
 	for_each_rw_member(ca, c, iter) {
 		struct journal_device *ja = &ca->journal;
 
 		if (!ja->nr)
 			continue;
 
-		while (should_discard_bucket(j, ja)) {
-			if (!reclaim_lock_held) {
-				/*
-				 * ugh:
-				 * might be called from __journal_res_get()
-				 * under wait_event() - have to go back to
-				 * TASK_RUNNING before doing something that
-				 * would block, but only if we're doing work:
-				 */
-				__set_current_state(TASK_RUNNING);
-
-				mutex_lock(&j->reclaim_lock);
-				reclaim_lock_held = true;
-				/* recheck under reclaim_lock: */
-				continue;
-			}
 
-			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->last_idx]),
-					ca->mi.bucket_size, GFP_NOIO);
-
-			spin_lock(&j->lock);
-			ja->last_idx = (ja->last_idx + 1) % ja->nr;
-			spin_unlock(&j->lock);
-
-			journal_wake(j);
-		}
-
-		/*
-		 * Write out enough btree nodes to free up 50% journal
-		 * buckets
-		 */
-		spin_lock(&j->lock);
+		/* Try to keep the journal at most half full: */
 		bucket_to_flush = (ja->cur_idx + (ja->nr >> 1)) % ja->nr;
 		seq_to_flush = max_t(u64, seq_to_flush,
 				     ja->bucket_seq[bucket_to_flush]);
-		spin_unlock(&j->lock);
 	}
 
 	/* Also flush if the pin fifo is more than half full */
-	spin_lock(&j->lock);
 	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:
 	 */
-	next_flush = j->last_flushed + msecs_to_jiffies(j->reclaim_delay_ms);
-	need_flush = time_after(jiffies, next_flush);
-
-	while ((pin = journal_get_next_pin(j, need_flush
-					   ? U64_MAX
-					   : seq_to_flush, &seq))) {
-		if (!reclaim_lock_held) {
-			spin_unlock(&j->lock);
-			__set_current_state(TASK_RUNNING);
-			mutex_lock(&j->reclaim_lock);
-			reclaim_lock_held = true;
-			spin_lock(&j->lock);
-			continue;
-		}
+	if (time_after(jiffies, j->last_flushed +
+		       msecs_to_jiffies(j->reclaim_delay_ms)))
+		min_nr = 1;
 
-		journal_pin_mark_flushing(j, pin, seq);
-		spin_unlock(&j->lock);
-
-		journal_pin_flush(j, pin, seq);
-
-		need_flush = false;
-		j->last_flushed = jiffies;
+	journal_flush_pins(j, seq_to_flush, min_nr);
 
-		spin_lock(&j->lock);
-	}
-
-	spin_unlock(&j->lock);
-
-	if (reclaim_lock_held)
-		mutex_unlock(&j->reclaim_lock);
+	mutex_unlock(&j->reclaim_lock);
 
 	if (!test_bit(BCH_FS_RO, &c->flags))
 		queue_delayed_work(c->journal_reclaim_wq, &j->reclaim_work,
@@ -342,8 +444,6 @@ void bch2_journal_reclaim_work(struct work_struct *work)
 
 static int journal_flush_done(struct journal *j, u64 seq_to_flush)
 {
-	struct journal_entry_pin *pin;
-	u64 pin_seq;
 	int ret;
 
 	ret = bch2_journal_error(j);
@@ -351,16 +451,10 @@ static int journal_flush_done(struct journal *j, u64 seq_to_flush)
 		return ret;
 
 	mutex_lock(&j->reclaim_lock);
-	spin_lock(&j->lock);
-
-	while ((pin = journal_get_next_pin(j, seq_to_flush, &pin_seq))) {
-		journal_pin_mark_flushing(j, pin, pin_seq);
-		spin_unlock(&j->lock);
 
-		journal_pin_flush(j, pin, pin_seq);
+	journal_flush_pins(j, seq_to_flush, 0);
 
-		spin_lock(&j->lock);
-	}
+	spin_lock(&j->lock);
 	/*
 	 * If journal replay hasn't completed, the unreplayed journal entries
 	 * hold refs on their corresponding sequence numbers
diff --git a/fs/bcachefs/journal_reclaim.h b/fs/bcachefs/journal_reclaim.h
index e06ac0492960..a9afb229541b 100644
--- a/fs/bcachefs/journal_reclaim.h
+++ b/fs/bcachefs/journal_reclaim.h
@@ -4,6 +4,10 @@
 
 #define JOURNAL_PIN	(32 * 1024)
 
+unsigned bch2_journal_dev_buckets_available(struct journal *,
+					    struct journal_device *);
+void bch2_journal_space_available(struct journal *);
+
 static inline bool journal_pin_active(struct journal_entry_pin *pin)
 {
 	return pin->seq != 0;
@@ -17,6 +21,8 @@ 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_add(struct journal *, u64, struct journal_entry_pin *,
 			  journal_pin_flush_fn);
 void bch2_journal_pin_update(struct journal *, u64, struct journal_entry_pin *,
@@ -28,7 +34,6 @@ void bch2_journal_pin_add_if_older(struct journal *,
 				  journal_pin_flush_fn);
 void bch2_journal_pin_flush(struct journal *, struct journal_entry_pin *);
 
-void bch2_journal_reclaim_fast(struct journal *);
 void bch2_journal_reclaim_work(struct work_struct *);
 
 void bch2_journal_flush_pins(struct journal *, u64);
diff --git a/fs/bcachefs/journal_types.h b/fs/bcachefs/journal_types.h
index 3372e87be124..2f48008820ac 100644
--- a/fs/bcachefs/journal_types.h
+++ b/fs/bcachefs/journal_types.h
@@ -136,6 +136,12 @@ struct journal {
 	unsigned		cur_entry_u64s;
 	unsigned		cur_entry_sectors;
 
+	/*
+	 * 0, or -ENOSPC if waiting on journal reclaim, or -EROFS if
+	 * insufficient devices:
+	 */
+	int			cur_entry_error;
+
 	/* Reserved space in journal entry to be used just prior to write */
 	unsigned		entry_u64s_reserved;