bcachefs: Rewrite journal_seq_blacklist machinery

Now, we store blacklisted journal sequence numbers in the superblock,
not the journal: this helps to greatly simplify the code, and more
importantly it's now implemented in a way that doesn't require all btree
nodes to be visited before starting the journal - instead, we
unconditionally blacklist the next 4 journal sequence numbers after an
unclean shutdown.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/bcachefs.h

@@ -185,6 +185,7 @@
 #include <linux/closure.h>
 #include <linux/kobject.h>
 #include <linux/list.h>
+#include <linux/math64.h>
 #include <linux/mutex.h>
 #include <linux/percpu-refcount.h>
 #include <linux/percpu-rwsem.h>
@@ -486,6 +487,7 @@ enum {
 	BCH_FS_RW,
 
 	/* shutdown: */
+	BCH_FS_STOPPING,
 	BCH_FS_EMERGENCY_RO,
 	BCH_FS_WRITE_DISABLE_COMPLETE,
 
@@ -511,6 +513,15 @@ struct bch_fs_pcpu {
 	u64			sectors_available;
 };
 
+struct journal_seq_blacklist_table {
+	size_t			nr;
+	struct journal_seq_blacklist_table_entry {
+		u64		start;
+		u64		end;
+		bool		dirty;
+	}			entries[0];
+};
+
 struct bch_fs {
 	struct closure		cl;
 
@@ -646,6 +657,11 @@ struct bch_fs {
 
 	struct io_clock		io_clock[2];
 
+	/* JOURNAL SEQ BLACKLIST */
+	struct journal_seq_blacklist_table *
+				journal_seq_blacklist_table;
+	struct work_struct	journal_seq_blacklist_gc_work;
+
 	/* ALLOCATOR */
 	spinlock_t		freelist_lock;
 	struct closure_waitlist	freelist_wait;

fs/bcachefs/bcachefs_format.h

@@ -909,7 +909,8 @@ struct bch_sb_field {
 	x(quota,	4)	\
 	x(disk_groups,	5)	\
 	x(clean,	6)	\
-	x(replicas,	7)
+	x(replicas,	7)	\
+	x(journal_seq_blacklist, 8)
 
 enum bch_sb_field_type {
 #define x(f, nr)	BCH_SB_FIELD_##f = nr,
@@ -1124,6 +1125,20 @@ struct bch_sb_field_clean {
 	};
 };
 
+struct journal_seq_blacklist_entry {
+	__le64			start;
+	__le64			end;
+};
+
+struct bch_sb_field_journal_seq_blacklist {
+	struct bch_sb_field	field;
+
+	union {
+		struct journal_seq_blacklist_entry start[0];
+		__u64		_data[0];
+	};
+};
+
 /* Superblock: */
 
 /*
@@ -1279,6 +1294,7 @@ enum bch_sb_features {
 	BCH_FEATURE_ZSTD		= 2,
 	BCH_FEATURE_ATOMIC_NLINK	= 3, /* should have gone under compat */
 	BCH_FEATURE_EC			= 4,
+	BCH_FEATURE_JOURNAL_SEQ_BLACKLIST_V3 = 5,
 	BCH_FEATURE_NR,
 };
 

fs/bcachefs/btree_io.c

@@ -770,7 +770,7 @@ int bch2_btree_node_read_done(struct bch_fs *c, struct btree *b, bool have_retry
 	struct btree_node *sorted;
 	struct bkey_packed *k;
 	struct bset *i;
-	bool used_mempool;
+	bool used_mempool, blacklisted;
 	unsigned u64s;
 	int ret, retry_read = 0, write = READ;
 
@@ -844,20 +844,15 @@ int bch2_btree_node_read_done(struct bch_fs *c, struct btree *b, bool have_retry
 
 		b->written += sectors;
 
-		ret = bch2_journal_seq_should_ignore(c, le64_to_cpu(i->journal_seq), b);
-		if (ret < 0) {
-			btree_err(BTREE_ERR_FATAL, c, b, i,
-				  "insufficient memory");
-			goto err;
-		}
+		blacklisted = bch2_journal_seq_is_blacklisted(c,
+					le64_to_cpu(i->journal_seq),
+					true);
 
-		if (ret) {
-			btree_err_on(first,
-				     BTREE_ERR_FIXABLE, c, b, i,
-				     "first btree node bset has blacklisted journal seq");
-			if (!first)
-				continue;
-		}
+		btree_err_on(blacklisted && first,
+			     BTREE_ERR_FIXABLE, c, b, i,
+			     "first btree node bset has blacklisted journal seq");
+		if (blacklisted && !first)
+			continue;
 
 		bch2_btree_node_iter_large_push(iter, b,
 					   i->start,
@@ -930,7 +925,6 @@ int bch2_btree_node_read_done(struct bch_fs *c, struct btree *b, bool have_retry
 out:
 	mempool_free(iter, &c->fill_iter);
 	return retry_read;
-err:
 fsck_err:
 	if (ret == BTREE_RETRY_READ) {
 		retry_read = 1;

fs/bcachefs/btree_iter.c

@@ -1156,6 +1156,8 @@ struct btree *bch2_btree_iter_next_node(struct btree_iter *iter, unsigned depth)
 	if (!btree_iter_node(iter, iter->level))
 		return NULL;
 
+	bch2_trans_cond_resched(iter->trans);
+
 	btree_iter_up(iter);
 
 	if (!bch2_btree_node_relock(iter, iter->level))

fs/bcachefs/inode.h

@@ -4,8 +4,6 @@
 
 #include "opts.h"
 
-#include <linux/math64.h>
-
 extern const char * const bch2_inode_opts[];
 
 const char *bch2_inode_invalid(const struct bch_fs *, struct bkey_s_c);

fs/bcachefs/journal.c

@@ -988,27 +988,57 @@ void bch2_fs_journal_stop(struct journal *j)
 	cancel_delayed_work_sync(&j->reclaim_work);
 }
 
-void bch2_fs_journal_start(struct journal *j)
+int bch2_fs_journal_start(struct journal *j, u64 cur_seq,
+			  struct list_head *journal_entries)
 {
 	struct bch_fs *c = container_of(j, struct bch_fs, journal);
-	struct journal_seq_blacklist *bl;
-	u64 blacklist = 0;
+	struct journal_entry_pin_list *p;
+	struct journal_replay *i;
+	u64 last_seq = cur_seq, nr, seq;
+
+	if (!list_empty(journal_entries))
+		last_seq = le64_to_cpu(list_last_entry(journal_entries,
+						       struct journal_replay,
+						       list)->j.last_seq);
+
+	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 -ENOMEM;
+		}
+	}
+
+	j->last_seq_ondisk	= last_seq;
+	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) {
+		INIT_LIST_HEAD(&p->list);
+		INIT_LIST_HEAD(&p->flushed);
+		atomic_set(&p->count, 0);
+		p->devs.nr = 0;
+	}
+
+	list_for_each_entry(i, journal_entries, list) {
+		seq = le64_to_cpu(i->j.seq);
+
+		BUG_ON(seq < last_seq || seq >= cur_seq);
 
-	list_for_each_entry(bl, &j->seq_blacklist, list)
-		blacklist = max(blacklist, bl->end);
+		p = journal_seq_pin(j, seq);
+
+		atomic_set(&p->count, 1);
+		p->devs = i->devs;
+	}
 
 	spin_lock(&j->lock);
 
 	set_bit(JOURNAL_STARTED, &j->flags);
 
-	while (journal_cur_seq(j) < blacklist)
-		journal_pin_new_entry(j, 0);
-
-	/*
-	 * __journal_entry_close() only inits the next journal entry when it
-	 * closes an open journal entry - the very first journal entry gets
-	 * initialized here:
-	 */
 	journal_pin_new_entry(j, 1);
 	bch2_journal_buf_init(j);
 
@@ -1017,12 +1047,7 @@ void bch2_fs_journal_start(struct journal *j)
 	bch2_journal_space_available(j);
 	spin_unlock(&j->lock);
 
-	/*
-	 * Adding entries to the next journal entry before allocating space on
-	 * disk for the next journal entry - this is ok, because these entries
-	 * only have to go down with the next journal entry we write:
-	 */
-	bch2_journal_seq_blacklist_write(j);
+	return 0;
 }
 
 /* init/exit: */
@@ -1090,8 +1115,6 @@ int bch2_fs_journal_init(struct journal *j)
 	INIT_DELAYED_WORK(&j->write_work, journal_write_work);
 	INIT_DELAYED_WORK(&j->reclaim_work, bch2_journal_reclaim_work);
 	init_waitqueue_head(&j->pin_flush_wait);
-	mutex_init(&j->blacklist_lock);
-	INIT_LIST_HEAD(&j->seq_blacklist);
 	mutex_init(&j->reclaim_lock);
 	mutex_init(&j->discard_lock);
 

fs/bcachefs/journal.h

@@ -472,8 +472,10 @@ int bch2_set_nr_journal_buckets(struct bch_fs *, struct bch_dev *,
 int bch2_dev_journal_alloc(struct bch_dev *);
 
 void bch2_dev_journal_stop(struct journal *, struct bch_dev *);
+
 void bch2_fs_journal_stop(struct journal *);
-void bch2_fs_journal_start(struct journal *);
+int bch2_fs_journal_start(struct journal *, u64, struct list_head *);
+
 void bch2_dev_journal_exit(struct bch_dev *);
 int bch2_dev_journal_init(struct bch_dev *, struct bch_sb *);
 void bch2_fs_journal_exit(struct journal *);

fs/bcachefs/journal_io.c

@@ -10,7 +10,6 @@
 #include "journal.h"
 #include "journal_io.h"
 #include "journal_reclaim.h"
-#include "journal_seq_blacklist.h"
 #include "replicas.h"
 #include "trace.h"
 
@@ -655,45 +654,11 @@ void bch2_journal_entries_free(struct list_head *list)
 	}
 }
 
-int bch2_journal_set_seq(struct bch_fs *c, u64 last_seq, u64 end_seq)
-{
-	struct journal *j = &c->journal;
-	struct journal_entry_pin_list *p;
-	u64 seq, nr = end_seq - last_seq + 1;
-
-	if (nr > j->pin.size) {
-		free_fifo(&j->pin);
-		init_fifo(&j->pin, roundup_pow_of_two(nr), GFP_KERNEL);
-		if (!j->pin.data) {
-			bch_err(c, "error reallocating journal fifo (%llu open entries)", nr);
-			return -ENOMEM;
-		}
-	}
-
-	atomic64_set(&j->seq, end_seq);
-	j->last_seq_ondisk = last_seq;
-
-	j->pin.front	= last_seq;
-	j->pin.back	= end_seq + 1;
-
-	fifo_for_each_entry_ptr(p, &j->pin, seq) {
-		INIT_LIST_HEAD(&p->list);
-		INIT_LIST_HEAD(&p->flushed);
-		atomic_set(&p->count, 0);
-		p->devs.nr = 0;
-	}
-
-	return 0;
-}
-
 int bch2_journal_read(struct bch_fs *c, struct list_head *list)
 {
-	struct journal *j = &c->journal;
 	struct journal_list jlist;
 	struct journal_replay *i;
-	struct journal_entry_pin_list *p;
 	struct bch_dev *ca;
-	u64 cur_seq, end_seq;
 	unsigned iter;
 	size_t keys = 0, entries = 0;
 	bool degraded = false;
@@ -725,17 +690,12 @@ int bch2_journal_read(struct bch_fs *c, struct list_head *list)
 	if (jlist.ret)
 		return jlist.ret;
 
-	if (list_empty(list)){
-		bch_err(c, "no journal entries found");
-		return BCH_FSCK_REPAIR_IMPOSSIBLE;
-	}
-
 	list_for_each_entry(i, list, list) {
+		struct jset_entry *entry;
+		struct bkey_i *k, *_n;
 		struct bch_replicas_padded replicas;
 		char buf[80];
 
-		bch2_devlist_to_replicas(&replicas.e, BCH_DATA_JOURNAL, i->devs);
-
 		ret = jset_validate_entries(c, &i->j, READ);
 		if (ret)
 			goto fsck_err;
@@ -745,6 +705,8 @@ int bch2_journal_read(struct bch_fs *c, struct list_head *list)
 		 * the devices - this is wrong:
 		 */
 
+		bch2_devlist_to_replicas(&replicas.e, BCH_DATA_JOURNAL, i->devs);
+
 		if (!degraded &&
 		    (test_bit(BCH_FS_REBUILD_REPLICAS, &c->flags) ||
 		     fsck_err_on(!bch2_replicas_marked(c, &replicas.e, false), c,
@@ -755,68 +717,18 @@ int bch2_journal_read(struct bch_fs *c, struct list_head *list)
 			if (ret)
 				return ret;
 		}
-	}
-
-	i = list_last_entry(list, struct journal_replay, list);
-
-	ret = bch2_journal_set_seq(c,
-				   le64_to_cpu(i->j.last_seq),
-				   le64_to_cpu(i->j.seq));
-	if (ret)
-		return ret;
-
-	mutex_lock(&j->blacklist_lock);
-
-	list_for_each_entry(i, list, list) {
-		p = journal_seq_pin(j, le64_to_cpu(i->j.seq));
-
-		atomic_set(&p->count, 1);
-		p->devs = i->devs;
-
-		if (bch2_journal_seq_blacklist_read(j, i)) {
-			mutex_unlock(&j->blacklist_lock);
-			return -ENOMEM;
-		}
-	}
-
-	mutex_unlock(&j->blacklist_lock);
-
-	cur_seq = journal_last_seq(j);
-	end_seq = le64_to_cpu(list_last_entry(list,
-				struct journal_replay, list)->j.seq);
-
-	list_for_each_entry(i, list, list) {
-		struct jset_entry *entry;
-		struct bkey_i *k, *_n;
-		bool blacklisted;
-
-		mutex_lock(&j->blacklist_lock);
-		while (cur_seq < le64_to_cpu(i->j.seq) &&
-		       bch2_journal_seq_blacklist_find(j, cur_seq))
-			cur_seq++;
-
-		blacklisted = bch2_journal_seq_blacklist_find(j,
-							 le64_to_cpu(i->j.seq));
-		mutex_unlock(&j->blacklist_lock);
-
-		fsck_err_on(blacklisted, c,
-			    "found blacklisted journal entry %llu",
-			    le64_to_cpu(i->j.seq));
-
-		fsck_err_on(le64_to_cpu(i->j.seq) != cur_seq, c,
-			"journal entries %llu-%llu missing! (replaying %llu-%llu)",
-			cur_seq, le64_to_cpu(i->j.seq) - 1,
-			journal_last_seq(j), end_seq);
-
-		cur_seq = le64_to_cpu(i->j.seq) + 1;
 
 		for_each_jset_key(k, _n, entry, &i->j)
 			keys++;
 		entries++;
 	}
 
-	bch_info(c, "journal read done, %zu keys in %zu entries, seq %llu",
-		 keys, entries, journal_cur_seq(j));
+	if (!list_empty(list)) {
+		i = list_last_entry(list, struct journal_replay, list);
+
+		bch_info(c, "journal read done, %zu keys in %zu entries, seq %llu",
+			 keys, entries, le64_to_cpu(i->j.seq));
+	}
 fsck_err:
 	return ret;
 }

fs/bcachefs/journal_io.h

@@ -35,7 +35,6 @@ static inline struct jset_entry *__jset_entry_type_next(struct jset *jset,
 	for_each_jset_entry_type(entry, jset, BCH_JSET_ENTRY_btree_keys)	\
 		vstruct_for_each_safe(entry, k, _n)
 
-int bch2_journal_set_seq(struct bch_fs *c, u64, u64);
 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 *);

fs/bcachefs/journal_seq_blacklist.c

 // SPDX-License-Identifier: GPL-2.0
 
 #include "bcachefs.h"
-#include "btree_update.h"
-#include "btree_update_interior.h"
-#include "error.h"
-#include "journal.h"
-#include "journal_io.h"
-#include "journal_reclaim.h"
+#include "btree_iter.h"
+#include "eytzinger.h"
 #include "journal_seq_blacklist.h"
+#include "super-io.h"
 
 /*
  * journal_seq_blacklist machinery:
@@ -37,327 +34,285 @@
  * record that it was blacklisted so that a) on recovery we don't think we have
  * missing journal entries and b) so that the btree code continues to ignore
  * that bset, until that btree node is rewritten.
- *
- * Blacklisted journal sequence numbers are themselves recorded as entries in
- * the journal.
  */
 
-/*
- * Called when journal needs to evict a blacklist entry to reclaim space: find
- * any btree nodes that refer to the blacklist journal sequence numbers, and
- * rewrite them:
- */
-static void journal_seq_blacklist_flush(struct journal *j,
-					struct journal_entry_pin *pin, u64 seq)
+static unsigned
+blacklist_nr_entries(struct bch_sb_field_journal_seq_blacklist *bl)
 {
-	struct bch_fs *c =
-		container_of(j, struct bch_fs, journal);
-	struct journal_seq_blacklist *bl =
-		container_of(pin, struct journal_seq_blacklist, pin);
-	struct blacklisted_node n;
-	struct closure cl;
-	unsigned i;
-	int ret;
+	return bl
+		? ((vstruct_end(&bl->field) - (void *) &bl->start[0]) /
+		   sizeof(struct journal_seq_blacklist_entry))
+		: 0;
+}
 
-	closure_init_stack(&cl);
+static unsigned sb_blacklist_u64s(unsigned nr)
+{
+	struct bch_sb_field_journal_seq_blacklist *bl;
 
-	for (i = 0;; i++) {
-		struct btree_trans trans;
-		struct btree_iter *iter;
-		struct btree *b;
+	return (sizeof(*bl) + sizeof(bl->start[0]) * nr) / sizeof(u64);
+}
 
-		bch2_trans_init(&trans, c);
+static struct bch_sb_field_journal_seq_blacklist *
+blacklist_entry_try_merge(struct bch_fs *c,
+			  struct bch_sb_field_journal_seq_blacklist *bl,
+			  unsigned i)
+{
+	unsigned nr = blacklist_nr_entries(bl);
+
+	if (le64_to_cpu(bl->start[i].end) >=
+	    le64_to_cpu(bl->start[i + 1].start)) {
+		bl->start[i].end = bl->start[i + 1].end;
+		--nr;
+		memmove(&bl->start[i],
+			&bl->start[i + 1],
+			sizeof(bl->start[0]) * (nr - i));
+
+		bl = bch2_sb_resize_journal_seq_blacklist(&c->disk_sb,
+							sb_blacklist_u64s(nr));
+		BUG_ON(!bl);
+	}
 
-		mutex_lock(&j->blacklist_lock);
-		if (i >= bl->nr_entries) {
-			mutex_unlock(&j->blacklist_lock);
-			break;
-		}
-		n = bl->entries[i];
-		mutex_unlock(&j->blacklist_lock);
+	return bl;
+}
 
-		iter = bch2_trans_get_node_iter(&trans, n.btree_id, n.pos,
-						0, 0, 0);
+int bch2_journal_seq_blacklist_add(struct bch_fs *c, u64 start, u64 end)
+{
+	struct bch_sb_field_journal_seq_blacklist *bl;
+	unsigned i, nr;
+	int ret = 0;
 
-		b = bch2_btree_iter_peek_node(iter);
+	mutex_lock(&c->sb_lock);
+	bl = bch2_sb_get_journal_seq_blacklist(c->disk_sb.sb);
+	nr = blacklist_nr_entries(bl);
 
-		/* The node might have already been rewritten: */
+	if (bl) {
+		for (i = 0; i < nr; i++) {
+			struct journal_seq_blacklist_entry *e =
+				bl->start + i;
 
-		if (b->data->keys.seq == n.seq) {
-			ret = bch2_btree_node_rewrite(c, iter, n.seq, 0);
-			if (ret) {
-				bch2_trans_exit(&trans);
-				bch2_fs_fatal_error(c,
-					"error %i rewriting btree node with blacklisted journal seq",
-					ret);
-				bch2_journal_halt(j);
-				return;
+			if (start == le64_to_cpu(e->start) &&
+			    end   == le64_to_cpu(e->end))
+				goto out;
+
+			if (start <= le64_to_cpu(e->start) &&
+			    end   >= le64_to_cpu(e->end)) {
+				e->start = cpu_to_le64(start);
+				e->end	= cpu_to_le64(end);
+
+				if (i + 1 < nr)
+					bl = blacklist_entry_try_merge(c,
+								bl, i);
+				if (i)
+					bl = blacklist_entry_try_merge(c,
+								bl, i - 1);
+				goto out_write_sb;
 			}
 		}
-
-		bch2_trans_exit(&trans);
 	}
 
-	for (i = 0;; i++) {
-		struct btree_update *as;
-		struct pending_btree_node_free *d;
-
-		mutex_lock(&j->blacklist_lock);
-		if (i >= bl->nr_entries) {
-			mutex_unlock(&j->blacklist_lock);
-			break;
-		}
-		n = bl->entries[i];
-		mutex_unlock(&j->blacklist_lock);
-redo_wait:
-		mutex_lock(&c->btree_interior_update_lock);
-
-		/*
-		 * Is the node on the list of pending interior node updates -
-		 * being freed? If so, wait for that to finish:
-		 */
-		for_each_pending_btree_node_free(c, as, d)
-			if (n.seq	== d->seq &&
-			    n.btree_id	== d->btree_id &&
-			    !d->level &&
-			    !bkey_cmp(n.pos, d->key.k.p)) {
-				closure_wait(&as->wait, &cl);
-				mutex_unlock(&c->btree_interior_update_lock);
-				closure_sync(&cl);
-				goto redo_wait;
-			}
-
-		mutex_unlock(&c->btree_interior_update_lock);
+	bl = bch2_sb_resize_journal_seq_blacklist(&c->disk_sb,
+					sb_blacklist_u64s(nr + 1));
+	if (!bl) {
+		ret = -ENOMEM;
+		goto out;
 	}
 
-	mutex_lock(&j->blacklist_lock);
+	bl->start[nr].start	= cpu_to_le64(start);
+	bl->start[nr].end	= cpu_to_le64(end);
+out_write_sb:
+	c->disk_sb.sb->features[0] |=
+		1ULL << BCH_FEATURE_JOURNAL_SEQ_BLACKLIST_V3;
 
-	bch2_journal_pin_drop(j, &bl->pin);
-	list_del(&bl->list);
-	kfree(bl->entries);
-	kfree(bl);
+	ret = bch2_write_super(c);
+out:
+	mutex_unlock(&c->sb_lock);
 
-	mutex_unlock(&j->blacklist_lock);
+	return ret;
 }
 
-/*
- * Determine if a particular sequence number is blacklisted - if so, return
- * blacklist entry:
- */
-struct journal_seq_blacklist *
-bch2_journal_seq_blacklist_find(struct journal *j, u64 seq)
+static int journal_seq_blacklist_table_cmp(const void *_l,
+					   const void *_r, size_t size)
 {
-	struct journal_seq_blacklist *bl;
+	const struct journal_seq_blacklist_table_entry *l = _l;
+	const struct journal_seq_blacklist_table_entry *r = _r;
 
-	lockdep_assert_held(&j->blacklist_lock);
-
-	list_for_each_entry(bl, &j->seq_blacklist, list)
-		if (seq >= bl->start && seq <= bl->end)
-			return bl;
-
-	return NULL;
+	return (l->start > r->start) - (l->start < r->start);
 }
 
-/*
- * Allocate a new, in memory blacklist entry:
- */
-static struct journal_seq_blacklist *
-bch2_journal_seq_blacklisted_new(struct journal *j, u64 start, u64 end)
+bool bch2_journal_seq_is_blacklisted(struct bch_fs *c, u64 seq,
+				     bool dirty)
 {
-	struct journal_seq_blacklist *bl;
+	struct journal_seq_blacklist_table *t = c->journal_seq_blacklist_table;
+	struct journal_seq_blacklist_table_entry search = { .start = seq };
+	int idx;
 
-	lockdep_assert_held(&j->blacklist_lock);
+	if (!t)
+		return false;
 
-	/*
-	 * When we start the journal, bch2_journal_start() will skip over @seq:
-	 */
+	idx = eytzinger0_find_le(t->entries, t->nr,
+				 sizeof(t->entries[0]),
+				 journal_seq_blacklist_table_cmp,
+				 &search);
+	if (idx < 0)
+		return false;
 
-	bl = kzalloc(sizeof(*bl), GFP_KERNEL);
-	if (!bl)
-		return NULL;
+	BUG_ON(t->entries[idx].start > seq);
 
-	bl->start	= start;
-	bl->end		= end;
+	if (seq >= t->entries[idx].end)
+		return false;
 
-	list_add_tail(&bl->list, &j->seq_blacklist);
-	return bl;
+	if (dirty)
+		t->entries[idx].dirty = true;
+	return true;
 }
 
-/*
- * Returns true if @seq is newer than the most recent journal entry that got
- * written, and data corresponding to @seq should be ignored - also marks @seq
- * as blacklisted so that on future restarts the corresponding data will still
- * be ignored:
- */
-int bch2_journal_seq_should_ignore(struct bch_fs *c, u64 seq, struct btree *b)
+int bch2_blacklist_table_initialize(struct bch_fs *c)
 {
-	struct journal *j = &c->journal;
-	struct journal_seq_blacklist *bl = NULL;
-	struct blacklisted_node *n;
-	u64 journal_seq;
-	int ret = 0;
-
-	if (!seq)
-		return 0;
+	struct bch_sb_field_journal_seq_blacklist *bl =
+		bch2_sb_get_journal_seq_blacklist(c->disk_sb.sb);
+	struct journal_seq_blacklist_table *t;
+	unsigned i, nr = blacklist_nr_entries(bl);
 
-	spin_lock(&j->lock);
-	journal_seq = journal_cur_seq(j);
-	spin_unlock(&j->lock);
+	BUG_ON(c->journal_seq_blacklist_table);
 
-	/* Interier updates aren't journalled: */
-	BUG_ON(b->level);
-	BUG_ON(seq > journal_seq && test_bit(BCH_FS_INITIAL_GC_DONE, &c->flags));
+	if (!bl)
+		return 0;
 
-	/*
-	 * Decrease this back to j->seq + 2 when we next rev the on disk format:
-	 * increasing it temporarily to work around bug in old kernels
-	 */
-	fsck_err_on(seq > journal_seq + 4, c,
-		    "bset journal seq too far in the future: %llu > %llu",
-		    seq, journal_seq);
+	t = kzalloc(sizeof(*t) + sizeof(t->entries[0]) * nr,
+		    GFP_KERNEL);
+	if (!t)
+		return -ENOMEM;
 
-	if (seq <= journal_seq &&
-	    list_empty_careful(&j->seq_blacklist))
-		return 0;
+	t->nr = nr;
 
-	mutex_lock(&j->blacklist_lock);
-
-	if (seq <= journal_seq) {
-		bl = bch2_journal_seq_blacklist_find(j, seq);
-		if (!bl)
-			goto out;
-	} else {
-		bch_verbose(c, "btree node %u:%llu:%llu has future journal sequence number %llu, blacklisting",
-			    b->btree_id, b->key.k.p.inode, b->key.k.p.offset, seq);
-
-		if (!j->new_blacklist) {
-			j->new_blacklist = bch2_journal_seq_blacklisted_new(j,
-						journal_seq + 1,
-						journal_seq + 1);
-			if (!j->new_blacklist) {
-				ret = -ENOMEM;
-				goto out;
-			}
-		}
-		bl = j->new_blacklist;
-		bl->end = max(bl->end, seq);
+	for (i = 0; i < nr; i++) {
+		t->entries[i].start	= le64_to_cpu(bl->start[i].start);
+		t->entries[i].end	= le64_to_cpu(bl->start[i].end);
 	}
 
-	for (n = bl->entries; n < bl->entries + bl->nr_entries; n++)
-		if (b->data->keys.seq	== n->seq &&
-		    b->btree_id		== n->btree_id &&
-		    !bkey_cmp(b->key.k.p, n->pos))
-			goto found_entry;
-
-	if (!bl->nr_entries ||
-	    is_power_of_2(bl->nr_entries)) {
-		n = krealloc(bl->entries,
-			     max_t(size_t, bl->nr_entries * 2, 8) * sizeof(*n),
-			     GFP_KERNEL);
-		if (!n) {
-			ret = -ENOMEM;
-			goto out;
-		}
-		bl->entries = n;
-	}
+	eytzinger0_sort(t->entries,
+			t->nr,
+			sizeof(t->entries[0]),
+			journal_seq_blacklist_table_cmp,
+			NULL);
 
-	bl->entries[bl->nr_entries++] = (struct blacklisted_node) {
-		.seq		= b->data->keys.seq,
-		.btree_id	= b->btree_id,
-		.pos		= b->key.k.p,
-	};
-found_entry:
-	ret = 1;
-out:
-fsck_err:
-	mutex_unlock(&j->blacklist_lock);
-	return ret;
+	c->journal_seq_blacklist_table = t;
+	return 0;
 }
 
-static int __bch2_journal_seq_blacklist_read(struct journal *j,
-					     struct journal_replay *i,
-					     u64 start, u64 end)
+static const char *
+bch2_sb_journal_seq_blacklist_validate(struct bch_sb *sb,
+				       struct bch_sb_field *f)
 {
-	struct bch_fs *c = container_of(j, struct bch_fs, journal);
-	struct journal_seq_blacklist *bl;
-
-	bch_verbose(c, "blacklisting existing journal seq %llu-%llu",
-		    start, end);
+	struct bch_sb_field_journal_seq_blacklist *bl =
+		field_to_type(f, journal_seq_blacklist);
+	struct journal_seq_blacklist_entry *i;
+	unsigned nr = blacklist_nr_entries(bl);
+
+	for (i = bl->start; i < bl->start + nr; i++) {
+		if (le64_to_cpu(i->start) >=
+		    le64_to_cpu(i->end))
+			return "entry start >= end";
+
+		if (i + 1 < bl->start + nr &&
+		    le64_to_cpu(i[0].end) >
+		    le64_to_cpu(i[1].start))
+			return "entries out of order";
+	}
 
-	bl = bch2_journal_seq_blacklisted_new(j, start, end);
-	if (!bl)
-		return -ENOMEM;
+	return NULL;
+}
 
-	bch2_journal_pin_add(j, le64_to_cpu(i->j.seq), &bl->pin,
-			     journal_seq_blacklist_flush);
-	return 0;
+static void bch2_sb_journal_seq_blacklist_to_text(struct printbuf *out,
+						  struct bch_sb *sb,
+						  struct bch_sb_field *f)
+{
+	struct bch_sb_field_journal_seq_blacklist *bl =
+		field_to_type(f, journal_seq_blacklist);
+	struct journal_seq_blacklist_entry *i;
+	unsigned nr = blacklist_nr_entries(bl);
+
+	for (i = bl->start; i < bl->start + nr; i++) {
+		if (i != bl->start)
+			pr_buf(out, " ");
+
+		pr_buf(out, "%llu-%llu",
+		       le64_to_cpu(i->start),
+		       le64_to_cpu(i->end));
+	}
 }
 
-/*
- * After reading the journal, find existing journal seq blacklist entries and
- * read them into memory:
- */
-int bch2_journal_seq_blacklist_read(struct journal *j,
-				    struct journal_replay *i)
+const struct bch_sb_field_ops bch_sb_field_ops_journal_seq_blacklist = {
+	.validate	= bch2_sb_journal_seq_blacklist_validate,
+	.to_text	= bch2_sb_journal_seq_blacklist_to_text
+};
+
+void bch2_blacklist_entries_gc(struct work_struct *work)
 {
-	struct jset_entry *entry;
-	int ret = 0;
+	struct bch_fs *c = container_of(work, struct bch_fs,
+					journal_seq_blacklist_gc_work);
+	struct journal_seq_blacklist_table *t;
+	struct bch_sb_field_journal_seq_blacklist *bl;
+	struct journal_seq_blacklist_entry *src, *dst;
+	struct btree_trans trans;
+	unsigned i, nr, new_nr;
+	int ret;
 
-	vstruct_for_each(&i->j, entry) {
-		switch (entry->type) {
-		case BCH_JSET_ENTRY_blacklist: {
-			struct jset_entry_blacklist *bl_entry =
-				container_of(entry, struct jset_entry_blacklist, entry);
+	bch2_trans_init(&trans, c);
 
-			ret = __bch2_journal_seq_blacklist_read(j, i,
-					le64_to_cpu(bl_entry->seq),
-					le64_to_cpu(bl_entry->seq));
-			break;
-		}
-		case BCH_JSET_ENTRY_blacklist_v2: {
-			struct jset_entry_blacklist_v2 *bl_entry =
-				container_of(entry, struct jset_entry_blacklist_v2, entry);
-
-			ret = __bch2_journal_seq_blacklist_read(j, i,
-					le64_to_cpu(bl_entry->start),
-					le64_to_cpu(bl_entry->end));
-			break;
-		}
-		}
+	for (i = 0; i < BTREE_ID_NR; i++) {
+		struct btree_iter *iter;
+		struct btree *b;
 
-		if (ret)
-			break;
+		for_each_btree_node(&trans, iter, i, POS_MIN,
+				    BTREE_ITER_PREFETCH, b)
+			if (test_bit(BCH_FS_STOPPING, &c->flags)) {
+				bch2_trans_exit(&trans);
+				return;
+			}
+		bch2_trans_iter_free(&trans, iter);
 	}
 
-	return ret;
-}
-
-/*
- * After reading the journal and walking the btree, we might have new journal
- * sequence numbers to blacklist - add entries to the next journal entry to be
- * written:
- */
-void bch2_journal_seq_blacklist_write(struct journal *j)
-{
-	struct journal_seq_blacklist *bl = j->new_blacklist;
-	struct jset_entry_blacklist_v2 *bl_entry;
-	struct jset_entry *entry;
+	ret = bch2_trans_exit(&trans);
+	if (ret)
+		return;
 
+	mutex_lock(&c->sb_lock);
+	bl = bch2_sb_get_journal_seq_blacklist(c->disk_sb.sb);
 	if (!bl)
-		return;
+		goto out;
 
-	entry = bch2_journal_add_entry_noreservation(journal_cur_buf(j),
-			(sizeof(*bl_entry) - sizeof(*entry)) / sizeof(u64));
+	nr = blacklist_nr_entries(bl);
+	dst = bl->start;
 
-	bl_entry = container_of(entry, struct jset_entry_blacklist_v2, entry);
-	bl_entry->entry.type	= BCH_JSET_ENTRY_blacklist_v2;
-	bl_entry->start		= cpu_to_le64(bl->start);
-	bl_entry->end		= cpu_to_le64(bl->end);
+	t = c->journal_seq_blacklist_table;
+	BUG_ON(nr != t->nr);
+
+	for (src = bl->start, i = eytzinger0_first(t->nr);
+	     src < bl->start + nr;
+	     src++, i = eytzinger0_next(i, nr)) {
+		BUG_ON(t->entries[i].start	!= le64_to_cpu(src->start));
+		BUG_ON(t->entries[i].end	!= le64_to_cpu(src->end));
+
+		if (t->entries[i].dirty)
+			*dst++ = *src;
+	}
 
-	bch2_journal_pin_add(j,
-			     journal_cur_seq(j),
-			     &bl->pin,
-			     journal_seq_blacklist_flush);
+	new_nr = dst - bl->start;
 
-	j->new_blacklist = NULL;
+	bch_info(c, "nr blacklist entries was %u, now %u", nr, new_nr);
+
+	if (new_nr != nr) {
+		bl = bch2_sb_resize_journal_seq_blacklist(&c->disk_sb,
+				new_nr ? sb_blacklist_u64s(new_nr) : 0);
+		BUG_ON(new_nr && !bl);
+
+		if (!new_nr)
+			c->disk_sb.sb->features[0] &=
+				~(1ULL << BCH_FEATURE_JOURNAL_SEQ_BLACKLIST_V3);
+
+		bch2_write_super(c);
+	}
+out:
+	mutex_unlock(&c->sb_lock);
 }

fs/bcachefs/journal_seq_blacklist.h

@@ -2,13 +2,12 @@
 #ifndef _BCACHEFS_JOURNAL_SEQ_BLACKLIST_H
 #define _BCACHEFS_JOURNAL_SEQ_BLACKLIST_H
 
-struct journal_replay;
-
-struct journal_seq_blacklist *
-bch2_journal_seq_blacklist_find(struct journal *, u64);
-int bch2_journal_seq_should_ignore(struct bch_fs *, u64, struct btree *);
-int bch2_journal_seq_blacklist_read(struct journal *,
-				    struct journal_replay *);
-void bch2_journal_seq_blacklist_write(struct journal *);
+bool bch2_journal_seq_is_blacklisted(struct bch_fs *, u64, bool);
+int bch2_journal_seq_blacklist_add(struct bch_fs *c, u64, u64);
+int bch2_blacklist_table_initialize(struct bch_fs *);
+
+extern const struct bch_sb_field_ops bch_sb_field_ops_journal_seq_blacklist;
+
+void bch2_blacklist_entries_gc(struct work_struct *);
 
 #endif /* _BCACHEFS_JOURNAL_SEQ_BLACKLIST_H */

fs/bcachefs/journal_types.h

@@ -54,24 +54,6 @@ struct journal_entry_pin {
 	u64				seq;
 };
 
-/* corresponds to a btree node with a blacklisted bset: */
-struct blacklisted_node {
-	__le64			seq;
-	enum btree_id		btree_id;
-	struct bpos		pos;
-};
-
-struct journal_seq_blacklist {
-	struct list_head	list;
-	u64			start;
-	u64			end;
-
-	struct journal_entry_pin pin;
-
-	struct blacklisted_node	*entries;
-	size_t			nr_entries;
-};
-
 struct journal_res {
 	bool			ref;
 	u8			idx;
@@ -222,10 +204,6 @@ struct journal {
 
 	u64			replay_journal_seq;
 
-	struct mutex		blacklist_lock;
-	struct list_head	seq_blacklist;
-	struct journal_seq_blacklist *new_blacklist;
-
 	struct write_point	wp;
 	spinlock_t		err_lock;
 

fs/bcachefs/recovery.c

@@ -12,6 +12,7 @@
 #include "error.h"
 #include "fsck.h"
 #include "journal_io.h"
+#include "journal_seq_blacklist.h"
 #include "quota.h"
 #include "recovery.h"
 #include "replicas.h"
@@ -99,18 +100,49 @@ static int verify_superblock_clean(struct bch_fs *c,
 	return ret;
 }
 
+static int
+verify_journal_entries_not_blacklisted_or_missing(struct bch_fs *c,
+						  struct list_head *journal)
+{
+	struct journal_replay *i =
+		list_last_entry(journal, struct journal_replay, list);
+	u64 start_seq	= le64_to_cpu(i->j.last_seq);
+	u64 end_seq	= le64_to_cpu(i->j.seq);
+	u64 seq		= start_seq;
+	int ret = 0;
+
+	list_for_each_entry(i, journal, list) {
+		fsck_err_on(seq != le64_to_cpu(i->j.seq), c,
+			"journal entries %llu-%llu missing! (replaying %llu-%llu)",
+			seq, le64_to_cpu(i->j.seq) - 1,
+			start_seq, end_seq);
+
+		seq = le64_to_cpu(i->j.seq);
+
+		fsck_err_on(bch2_journal_seq_is_blacklisted(c, seq, false), c,
+			    "found blacklisted journal entry %llu", seq);
+
+		do {
+			seq++;
+		} while (bch2_journal_seq_is_blacklisted(c, seq, false));
+	}
+fsck_err:
+	return ret;
+}
+
 static struct bch_sb_field_clean *read_superblock_clean(struct bch_fs *c)
 {
 	struct bch_sb_field_clean *clean, *sb_clean;
-
-	if (!c->sb.clean)
-		return NULL;
+	int ret;
 
 	mutex_lock(&c->sb_lock);
 	sb_clean = bch2_sb_get_clean(c->disk_sb.sb);
-	if (!sb_clean) {
+
+	if (fsck_err_on(!sb_clean, c,
+			"superblock marked clean but clean section not present")) {
+		SET_BCH_SB_CLEAN(c->disk_sb.sb, false);
+		c->sb.clean = false;
 		mutex_unlock(&c->sb_lock);
-		bch_err(c, "superblock marked clean but clean section not present");
 		return NULL;
 	}
 
@@ -128,6 +160,9 @@ static struct bch_sb_field_clean *read_superblock_clean(struct bch_fs *c)
 	mutex_unlock(&c->sb_lock);
 
 	return clean;
+fsck_err:
+	mutex_unlock(&c->sb_lock);
+	return ERR_PTR(ret);
 }
 
 static int journal_replay_entry_early(struct bch_fs *c,
@@ -179,14 +214,32 @@ static int journal_replay_entry_early(struct bch_fs *c,
 					      le64_to_cpu(u->v));
 		break;
 	}
+	case BCH_JSET_ENTRY_blacklist: {
+		struct jset_entry_blacklist *bl_entry =
+			container_of(entry, struct jset_entry_blacklist, entry);
+
+		ret = bch2_journal_seq_blacklist_add(c,
+				le64_to_cpu(bl_entry->seq),
+				le64_to_cpu(bl_entry->seq) + 1);
+		break;
+	}
+	case BCH_JSET_ENTRY_blacklist_v2: {
+		struct jset_entry_blacklist_v2 *bl_entry =
+			container_of(entry, struct jset_entry_blacklist_v2, entry);
+
+		ret = bch2_journal_seq_blacklist_add(c,
+				le64_to_cpu(bl_entry->start),
+				le64_to_cpu(bl_entry->end) + 1);
+		break;
+	}
 	}
 
 	return ret;
 }
 
-static int load_journal_metadata(struct bch_fs *c,
-				 struct bch_sb_field_clean *clean,
-				 struct list_head *journal)
+static int journal_replay_early(struct bch_fs *c,
+				struct bch_sb_field_clean *clean,
+				struct list_head *journal)
 {
 	struct jset_entry *entry;
 	int ret;
@@ -300,37 +353,76 @@ static bool journal_empty(struct list_head *journal)
 int bch2_fs_recovery(struct bch_fs *c)
 {
 	const char *err = "cannot allocate memory";
-	struct bch_sb_field_clean *clean;
+	struct bch_sb_field_clean *clean = NULL;
+	u64 journal_seq;
 	LIST_HEAD(journal);
 	int ret;
 
-	clean = read_superblock_clean(c);
-	if (clean)
+	if (c->sb.clean)
+		clean = read_superblock_clean(c);
+	ret = PTR_ERR_OR_ZERO(clean);
+	if (ret)
+		goto err;
+
+	if (c->sb.clean)
 		bch_info(c, "recovering from clean shutdown, journal seq %llu",
 			 le64_to_cpu(clean->journal_seq));
 
-	if (!clean || c->opts.fsck) {
+	if (!c->replicas.entries) {
+		bch_info(c, "building replicas info");
+		set_bit(BCH_FS_REBUILD_REPLICAS, &c->flags);
+	}
+
+	if (!c->sb.clean || c->opts.fsck) {
+		struct jset *j;
+
 		ret = bch2_journal_read(c, &journal);
 		if (ret)
 			goto err;
 
-		ret = verify_superblock_clean(c, &clean,
-			&list_last_entry(&journal, struct journal_replay,
-					 list)->j);
+		fsck_err_on(c->sb.clean && !journal_empty(&journal), c,
+			    "filesystem marked clean but journal not empty");
+
+		if (!c->sb.clean && list_empty(&journal)){
+			bch_err(c, "no journal entries found");
+			ret = BCH_FSCK_REPAIR_IMPOSSIBLE;
+			goto err;
+		}
+
+		j = &list_last_entry(&journal, struct journal_replay, list)->j;
+
+		ret = verify_superblock_clean(c, &clean, j);
 		if (ret)
 			goto err;
+
+		journal_seq = le64_to_cpu(j->seq) + 1;
 	} else {
-		ret = bch2_journal_set_seq(c,
-					   le64_to_cpu(clean->journal_seq),
-					   le64_to_cpu(clean->journal_seq));
-		if (ret)
+		journal_seq = le64_to_cpu(clean->journal_seq) + 1;
+	}
+
+	ret = journal_replay_early(c, clean, &journal);
+	if (ret)
+		goto err;
+
+	if (!c->sb.clean) {
+		ret = bch2_journal_seq_blacklist_add(c,
+				journal_seq,
+				journal_seq + 4);
+		if (ret) {
+			bch_err(c, "error creating new journal seq blacklist entry");
 			goto err;
+		}
+
+		journal_seq += 4;
 	}
 
-	fsck_err_on(clean && !journal_empty(&journal), c,
-		    "filesystem marked clean but journal not empty");
+	ret = bch2_blacklist_table_initialize(c);
+
+	ret = verify_journal_entries_not_blacklisted_or_missing(c, &journal);
+	if (ret)
+		goto err;
 
-	ret = load_journal_metadata(c, clean, &journal);
+	ret = bch2_fs_journal_start(&c->journal, journal_seq, &journal);
 	if (ret)
 		goto err;
 
@@ -351,11 +443,6 @@ int bch2_fs_recovery(struct bch_fs *c)
 
 	set_bit(BCH_FS_ALLOC_READ_DONE, &c->flags);
 
-	if (!c->replicas.entries) {
-		bch_info(c, "building replicas info");
-		set_bit(BCH_FS_REBUILD_REPLICAS, &c->flags);
-	}
-
 	if (c->opts.fsck ||
 	    !(c->sb.compat & (1ULL << BCH_COMPAT_FEAT_ALLOC_INFO)) ||
 	    test_bit(BCH_FS_REBUILD_REPLICAS, &c->flags)) {
@@ -377,13 +464,6 @@ int bch2_fs_recovery(struct bch_fs *c)
 	if (c->sb.encryption_type && !c->sb.clean)
 		atomic64_add(1 << 16, &c->key_version);
 
-	/*
-	 * bch2_fs_journal_start() can't happen sooner, or btree_gc_finish()
-	 * will give spurious errors about oldest_gen > bucket_gen -
-	 * this is a hack but oh well.
-	 */
-	bch2_fs_journal_start(&c->journal);
-
 	if (c->opts.noreplay)
 		goto out;
 
@@ -424,6 +504,10 @@ int bch2_fs_recovery(struct bch_fs *c)
 		SET_BCH_SB_HAS_ERRORS(c->disk_sb.sb, 0);
 	}
 	mutex_unlock(&c->sb_lock);
+
+	if (c->journal_seq_blacklist_table &&
+	    c->journal_seq_blacklist_table->nr > 128)
+		queue_work(system_long_wq, &c->journal_seq_blacklist_gc_work);
 out:
 	bch2_journal_entries_free(&journal);
 	kfree(clean);
@@ -472,7 +556,7 @@ int bch2_fs_initialize(struct bch_fs *c)
 	 * journal_res_get() will crash if called before this has
 	 * set up the journal.pin FIFO and journal.cur pointer:
 	 */
-	bch2_fs_journal_start(&c->journal);
+	bch2_fs_journal_start(&c->journal, 1, &journal);
 	bch2_journal_set_replay_done(&c->journal);
 
 	err = "error going read write";

fs/bcachefs/super-io.c

@@ -7,6 +7,7 @@
 #include "error.h"
 #include "io.h"
 #include "journal.h"
+#include "journal_seq_blacklist.h"
 #include "replicas.h"
 #include "quota.h"
 #include "super-io.h"

fs/bcachefs/super.c

@@ -30,6 +30,7 @@
 #include "io.h"
 #include "journal.h"
 #include "journal_reclaim.h"
+#include "journal_seq_blacklist.h"
 #include "move.h"
 #include "migrate.h"
 #include "movinggc.h"
@@ -468,6 +469,7 @@ static void bch2_fs_free(struct bch_fs *c)
 	kfree(c->replicas.entries);
 	kfree(c->replicas_gc.entries);
 	kfree(rcu_dereference_protected(c->disk_groups, 1));
+	kfree(c->journal_seq_blacklist_table);
 
 	if (c->journal_reclaim_wq)
 		destroy_workqueue(c->journal_reclaim_wq);
@@ -496,6 +498,10 @@ void bch2_fs_stop(struct bch_fs *c)
 
 	bch_verbose(c, "shutting down");
 
+	set_bit(BCH_FS_STOPPING, &c->flags);
+
+	cancel_work_sync(&c->journal_seq_blacklist_gc_work);
+
 	for_each_member_device(ca, c, i)
 		if (ca->kobj.state_in_sysfs &&
 		    ca->disk_sb.bdev)
@@ -631,6 +637,9 @@ static struct bch_fs *bch2_fs_alloc(struct bch_sb *sb, struct bch_opts opts)
 	spin_lock_init(&c->btree_write_error_lock);
 	INIT_WORK(&c->btree_write_error_work, bch2_btree_write_error_work);
 
+	INIT_WORK(&c->journal_seq_blacklist_gc_work,
+		  bch2_blacklist_entries_gc);
+
 	INIT_LIST_HEAD(&c->fsck_errors);
 	mutex_init(&c->fsck_error_lock);