diff --git a/.bcachefs_revision b/.bcachefs_revision
index ca5f3e9d..667f3d1d 100644
--- a/.bcachefs_revision
+++ b/.bcachefs_revision
@@ -1 +1 @@
-5fe20ac58af402e8ad9ace0bcf9daad524e3005d
+d7354b97c0100568c5696b192e30335a3666062f
diff --git a/libbcachefs/alloc/replicas.c b/libbcachefs/alloc/replicas.c
index 7b32f371..f0722e5b 100644
--- a/libbcachefs/alloc/replicas.c
+++ b/libbcachefs/alloc/replicas.c
@@ -16,25 +16,40 @@ DEFINE_CLASS(bch_replicas_cpu, struct bch_replicas_cpu,
 	     kfree(_T.entries),
 	     (struct bch_replicas_cpu) {}, void)
 
-static inline struct bch_replicas_entry_v1 *
+static inline struct bch_replicas_entry_cpu *
 cpu_replicas_entry(struct bch_replicas_cpu *r, unsigned i)
 {
 	return (void *) r->entries + r->entry_size * i;
 }
 
+static inline unsigned __cpu_replicas_entry_bytes(unsigned v1_bytes)
+{
+	return offsetof(struct bch_replicas_entry_cpu, e) + v1_bytes;
+}
+
+static inline unsigned cpu_replicas_entry_bytes(struct bch_replicas_entry_cpu *e)
+{
+	return __cpu_replicas_entry_bytes(replicas_entry_bytes(&e->e));
+}
+
 #define for_each_cpu_replicas_entry(_r, _i)						\
-	for (struct bch_replicas_entry_v1 *_i = (_r)->entries;				\
+	for (struct bch_replicas_entry_cpu *_i = (_r)->entries;				\
 	     (void *) (_i) < (void *) (_r)->entries + (_r)->nr * (_r)->entry_size;	\
 	     _i = (void *) (_i) + (_r)->entry_size)
 
 static int bch2_cpu_replicas_to_sb_replicas(struct bch_fs *,
 					    struct bch_replicas_cpu *);
 
-/* Some (buggy!) compilers don't allow memcmp to be passed as a pointer */
-static int bch2_memcmp(const void *l, const void *r,  const void *priv)
+static int cpu_replicas_entry_cmp(const struct bch_replicas_entry_cpu *l,
+				  const struct bch_replicas_entry_cpu *r,
+				  size_t size)
 {
-	size_t size = (size_t) priv;
-	return memcmp(l, r, size);
+	return memcmp(&l->e, &r->e, size - offsetof(struct bch_replicas_entry_cpu, e));
+}
+
+static int cpu_replicas_entry_cmp_r(const void *l, const void *r,  const void *priv)
+{
+	return cpu_replicas_entry_cmp(l, r, (size_t) priv);
 }
 
 /* Replicas tracking - in memory: */
@@ -60,7 +75,8 @@ void bch2_replicas_entry_sort(struct bch_replicas_entry_v1 *e)
 static void bch2_cpu_replicas_sort(struct bch_replicas_cpu *r)
 {
 	eytzinger0_sort_r(r->entries, r->nr, r->entry_size,
-			  bch2_memcmp, NULL, (void *)(size_t)r->entry_size);
+			  cpu_replicas_entry_cmp_r, NULL,
+			  (void *)(size_t)r->entry_size);
 }
 
 static void bch2_replicas_entry_v0_to_text(struct printbuf *out,
@@ -85,6 +101,13 @@ void bch2_replicas_entry_to_text(struct printbuf *out,
 	prt_printf(out, "]");
 }
 
+static void bch2_replicas_entry_cpu_to_text(struct printbuf *out,
+					    struct bch_replicas_entry_cpu *e)
+{
+	prt_printf(out, "ref=%u ", atomic_read(&e->ref));
+	bch2_replicas_entry_to_text(out, &e->e);
+}
+
 static int bch2_replicas_entry_sb_validate(struct bch_replicas_entry_v1 *r,
 					   struct bch_sb *sb,
 					   struct printbuf *err)
@@ -151,7 +174,7 @@ void bch2_cpu_replicas_to_text(struct printbuf *out,
 			prt_printf(out, " ");
 		first = false;
 
-		bch2_replicas_entry_to_text(out, i);
+		bch2_replicas_entry_cpu_to_text(out, i);
 	}
 }
 
@@ -232,6 +255,44 @@ void bch2_devlist_to_replicas(struct bch_replicas_entry_v1 *e,
 	bch2_replicas_entry_sort(e);
 }
 
+/* @l is bch_replicas_entry_v1, @r is bch_replicas_entry_cpu */
+static int replicas_entry_search_cmp(const void *_l, const void *_r,  const void *priv)
+{
+	const struct bch_replicas_entry_v1  *l = _l;
+	const struct bch_replicas_entry_cpu *r = _r;
+	size_t size = (size_t) priv;
+
+	return memcmp(l, &r->e, size);
+}
+
+static inline struct bch_replicas_entry_cpu *
+replicas_entry_search(struct bch_replicas_cpu *r,
+		      struct bch_replicas_entry_v1 *search)
+{
+	verify_replicas_entry(search);
+
+	size_t entry_size = replicas_entry_bytes(search);
+	int idx = likely(__cpu_replicas_entry_bytes(entry_size) <= r->entry_size)
+		? eytzinger0_find_r(r->entries, r->nr, r->entry_size,
+				    replicas_entry_search_cmp,
+				    (void *) entry_size, search)
+		: -1;
+	return idx >= 0 ? cpu_replicas_entry(r, idx) : NULL;
+}
+
+bool bch2_replicas_marked_locked(struct bch_fs *c,
+			  struct bch_replicas_entry_v1 *search)
+{
+	return !search->nr_devs || replicas_entry_search(&c->replicas, search);
+}
+
+bool bch2_replicas_marked(struct bch_fs *c,
+			  struct bch_replicas_entry_v1 *search)
+{
+	guard(percpu_read)(&c->mark_lock);
+	return bch2_replicas_marked_locked(c, search);
+}
+
 static struct bch_replicas_cpu
 cpu_replicas_add_entry(struct bch_fs *c,
 		       struct bch_replicas_cpu *old,
@@ -240,9 +301,12 @@ cpu_replicas_add_entry(struct bch_fs *c,
 	struct bch_replicas_cpu new = {
 		.nr		= old->nr + 1,
 		.entry_size	= max_t(unsigned, old->entry_size,
-					replicas_entry_bytes(new_entry)),
+					__cpu_replicas_entry_bytes(replicas_entry_bytes(new_entry))),
 	};
 
+	/* alignment */
+	new.entry_size = round_up(new.entry_size, sizeof(atomic_t));
+
 	new.entries = kcalloc(new.nr, new.entry_size, GFP_KERNEL);
 	if (!new.entries)
 		return new;
@@ -252,7 +316,7 @@ cpu_replicas_add_entry(struct bch_fs *c,
 		       cpu_replicas_entry(old, i),
 		       old->entry_size);
 
-	memcpy(cpu_replicas_entry(&new, old->nr),
+	memcpy(&cpu_replicas_entry(&new, old->nr)->e,
 	       new_entry,
 	       replicas_entry_bytes(new_entry));
 
@@ -260,152 +324,56 @@ cpu_replicas_add_entry(struct bch_fs *c,
 	return new;
 }
 
-static inline struct bch_replicas_entry_v1 *
-replicas_entry_search(struct bch_replicas_cpu *r,
-		      struct bch_replicas_entry_v1 *search)
-{
-	verify_replicas_entry(search);
-
-	size_t entry_size = replicas_entry_bytes(search);
-	int idx = likely(entry_size <= r->entry_size)
-		? eytzinger0_find_r(r->entries, r->nr, r->entry_size,
-				    bch2_memcmp, (void *) entry_size, search)
-		: -1;
-	return idx >= 0 ? cpu_replicas_entry(r, idx) : NULL;
-}
-
-bool bch2_replicas_marked_locked(struct bch_fs *c,
-			  struct bch_replicas_entry_v1 *search)
-{
-	return !search->nr_devs ||
-		(replicas_entry_search(&c->replicas, search) &&
-		 (likely((!c->replicas_gc.entries)) ||
-		  replicas_entry_search(&c->replicas_gc, search)));
-}
-
-bool bch2_replicas_marked(struct bch_fs *c,
-			  struct bch_replicas_entry_v1 *search)
-{
-	guard(percpu_read)(&c->mark_lock);
-	return bch2_replicas_marked_locked(c, search);
-}
-
 noinline
 static int bch2_mark_replicas_slowpath(struct bch_fs *c,
-				struct bch_replicas_entry_v1 *new_entry)
+				struct bch_replicas_entry_v1 *new_entry,
+				unsigned ref)
 {
 	verify_replicas_entry(new_entry);
 
-	CLASS(bch_replicas_cpu, new_r)();
-	CLASS(bch_replicas_cpu, new_gc)();
-
 	guard(mutex)(&c->sb_lock);
+	bool write_sb = false;
 
-	if (c->replicas_gc.entries &&
-	    !replicas_entry_search(&c->replicas_gc, new_entry)) {
-		new_gc = cpu_replicas_add_entry(c, &c->replicas_gc, new_entry);
-		if (!new_gc.entries)
-			return bch_err_throw(c, ENOMEM_cpu_replicas);
-	}
-
-	if (!replicas_entry_search(&c->replicas, new_entry)) {
-		new_r = cpu_replicas_add_entry(c, &c->replicas, new_entry);
-		if (!new_r.entries)
-			return bch_err_throw(c, ENOMEM_cpu_replicas);
-
-		try(bch2_cpu_replicas_to_sb_replicas(c, &new_r));
-	}
-
-	if (!new_r.entries &&
-	    !new_gc.entries)
-		return 0;
-
-	/* allocations done, now commit: */
-
-	if (new_r.entries)
-		bch2_write_super(c);
-
-	/* don't update in memory replicas until changes are persistent */
 	scoped_guard(percpu_write, &c->mark_lock) {
-		if (new_r.entries)
+		if (!replicas_entry_search(&c->replicas, new_entry)) {
+			CLASS(bch_replicas_cpu, new_r)();
+
+			new_r = cpu_replicas_add_entry(c, &c->replicas, new_entry);
+			if (!new_r.entries)
+				return bch_err_throw(c, ENOMEM_cpu_replicas);
+
+			try(bch2_cpu_replicas_to_sb_replicas(c, &new_r));
+
 			swap(c->replicas, new_r);
-		if (new_gc.entries)
-			swap(new_gc, c->replicas_gc);
+			write_sb = true;
+		}
+
+		atomic_add(ref, &replicas_entry_search(&c->replicas, new_entry)->ref);
 	}
 
+	/* After dropping mark_lock */
+	if (write_sb)
+		bch2_write_super(c);
+
 	return 0;
 }
 
 int bch2_mark_replicas(struct bch_fs *c, struct bch_replicas_entry_v1 *r)
 {
 	return likely(bch2_replicas_marked(c, r))
-		? 0 : bch2_mark_replicas_slowpath(c, r);
+		? 0 : bch2_mark_replicas_slowpath(c, r, 0);
 }
 
-/*
- * Old replicas_gc mechanism: only used for journal replicas entries now, should
- * die at some point:
- */
-
-int bch2_replicas_gc_end(struct bch_fs *c, int ret)
+static void __replicas_entry_kill(struct bch_fs *c, struct bch_replicas_entry_cpu *e)
 {
-	lockdep_assert_held(&c->replicas_gc_lock);
+	struct bch_replicas_cpu *r = &c->replicas;
 
-	guard(mutex)(&c->sb_lock);
-	scoped_guard(percpu_write, &c->mark_lock) {
-		ret =   ret ?:
-			bch2_cpu_replicas_to_sb_replicas(c, &c->replicas_gc);
-		if (!ret)
-			swap(c->replicas, c->replicas_gc);
+	memcpy(e, cpu_replicas_entry(r, --r->nr), r->entry_size);
+	bch2_cpu_replicas_sort(r);
 
-		kfree(c->replicas_gc.entries);
-		c->replicas_gc.entries = NULL;
-	}
-
-	if (!ret)
-		bch2_write_super(c);
-
-	return ret;
-}
-
-int bch2_replicas_gc_start(struct bch_fs *c, unsigned typemask)
-{
-	lockdep_assert_held(&c->replicas_gc_lock);
-
-	guard(mutex)(&c->sb_lock);
-	BUG_ON(c->replicas_gc.entries);
-
-	c->replicas_gc.nr		= 0;
-	c->replicas_gc.entry_size	= 0;
-
-	for_each_cpu_replicas_entry(&c->replicas, e) {
-		/* Preserve unknown data types */
-		if (e->data_type >= BCH_DATA_NR ||
-		    !(BIT(e->data_type) & typemask)) {
-			c->replicas_gc.nr++;
-			c->replicas_gc.entry_size =
-				max_t(unsigned, c->replicas_gc.entry_size,
-				      replicas_entry_bytes(e));
-		}
-	}
-
-	c->replicas_gc.entries = kcalloc(c->replicas_gc.nr,
-					 c->replicas_gc.entry_size,
-					 GFP_KERNEL);
-	if (!c->replicas_gc.entries) {
-		bch_err(c, "error allocating c->replicas_gc");
-		return bch_err_throw(c, ENOMEM_replicas_gc);
-	}
-
-	unsigned i = 0;
-	for_each_cpu_replicas_entry(&c->replicas, e)
-		if (e->data_type >= BCH_DATA_NR ||
-		    !(BIT(e->data_type) & typemask))
-			memcpy(cpu_replicas_entry(&c->replicas_gc, i++),
-			       e, c->replicas_gc.entry_size);
-
-	bch2_cpu_replicas_sort(&c->replicas_gc);
-	return 0;
+	int ret = bch2_cpu_replicas_to_sb_replicas(c, r);
+	if (WARN(ret, "bch2_cpu_replicas_to_sb_replicas() error: %s", bch2_err_str(ret)))
+		return;
 }
 
 void bch2_replicas_entry_kill(struct bch_fs *c, struct bch_replicas_entry_v1 *kill)
@@ -413,18 +381,95 @@ void bch2_replicas_entry_kill(struct bch_fs *c, struct bch_replicas_entry_v1 *ki
 	lockdep_assert_held(&c->mark_lock);
 	lockdep_assert_held(&c->sb_lock);
 
-	struct bch_replicas_cpu *r = &c->replicas;
+	struct bch_replicas_entry_cpu *e = replicas_entry_search(&c->replicas, kill);
 
-	struct bch_replicas_entry_v1 *e = replicas_entry_search(&c->replicas, kill);
 	if (WARN(!e, "replicas entry not found in sb"))
 		return;
 
-	memcpy(e, cpu_replicas_entry(r, --r->nr), r->entry_size);
+	__replicas_entry_kill(c, e);
 
-	bch2_cpu_replicas_sort(r);
+	/* caller does write_super() after dropping mark_lock */
+}
 
-	int ret = bch2_cpu_replicas_to_sb_replicas(c, r);
-	WARN(ret, "bch2_cpu_replicas_to_sb_replicas() error: %s", bch2_err_str(ret));
+void bch2_replicas_entry_put_many(struct bch_fs *c, struct bch_replicas_entry_v1 *r, unsigned nr)
+{
+	if (!r->nr_devs)
+		return;
+
+	BUG_ON(r->data_type != BCH_DATA_journal);
+	verify_replicas_entry(r);
+
+	scoped_guard(percpu_read, &c->mark_lock) {
+		struct bch_replicas_entry_cpu *e = replicas_entry_search(&c->replicas, r);
+
+		int v = atomic_sub_return(nr, &e->ref);
+		BUG_ON(v < 0);
+		if (v)
+			return;
+	}
+
+	guard(mutex)(&c->sb_lock);
+	scoped_guard(percpu_write, &c->mark_lock) {
+		struct bch_replicas_entry_cpu *e = replicas_entry_search(&c->replicas, r);
+		if (e && !atomic_read(&e->ref))
+			__replicas_entry_kill(c, e);
+	}
+
+	bch2_write_super(c);
+}
+
+static inline bool bch2_replicas_entry_get_inmem(struct bch_fs *c, struct bch_replicas_entry_v1 *r)
+{
+	guard(percpu_read)(&c->mark_lock);
+	struct bch_replicas_entry_cpu *e = replicas_entry_search(&c->replicas, r);
+	if (e)
+		atomic_inc(&e->ref);
+	return e != NULL;
+}
+
+int bch2_replicas_entry_get(struct bch_fs *c, struct bch_replicas_entry_v1 *r)
+{
+	if (!r->nr_devs)
+		return 0;
+
+	BUG_ON(r->data_type != BCH_DATA_journal);
+	verify_replicas_entry(r);
+
+	return bch2_replicas_entry_get_inmem(c, r)
+		? 0
+		: bch2_mark_replicas_slowpath(c, r, 1);
+}
+
+int bch2_replicas_gc_reffed(struct bch_fs *c)
+{
+	bool write_sb = false;
+
+	guard(mutex)(&c->sb_lock);
+
+	scoped_guard(percpu_write, &c->mark_lock) {
+		unsigned dst = 0;
+		for (unsigned i = 0; i < c->replicas.nr; i++) {
+			struct bch_replicas_entry_cpu *e =
+				cpu_replicas_entry(&c->replicas, i);
+
+			if (e->e.data_type != BCH_DATA_journal ||
+			    atomic_read(&e->ref))
+				memcpy(cpu_replicas_entry(&c->replicas, dst++),
+				       e,
+				       c->replicas.entry_size);
+		}
+
+		if (c->replicas.nr != dst) {
+			c->replicas.nr = dst;
+			bch2_cpu_replicas_sort(&c->replicas);
+
+			try(bch2_cpu_replicas_to_sb_replicas(c, &c->replicas));
+		}
+	}
+
+	if (write_sb)
+		bch2_write_super(c);
+	return 0;
 }
 
 /* Replicas tracking - superblock: */
@@ -441,6 +486,9 @@ __bch2_sb_replicas_to_cpu_replicas(struct bch_sb_field_replicas *sb_r,
 		nr++;
 	}
 
+	entry_size = __cpu_replicas_entry_bytes(entry_size);
+	entry_size = round_up(entry_size, sizeof(atomic_t));
+
 	cpu_r->entries = kcalloc(nr, entry_size, GFP_KERNEL);
 	if (!cpu_r->entries)
 		return -BCH_ERR_ENOMEM_cpu_replicas;
@@ -448,10 +496,10 @@ __bch2_sb_replicas_to_cpu_replicas(struct bch_sb_field_replicas *sb_r,
 	cpu_r->nr		= nr;
 	cpu_r->entry_size	= entry_size;
 
-	for_each_replicas_entry(sb_r, e) {
-		struct bch_replicas_entry_v1 *dst = cpu_replicas_entry(cpu_r, idx++);
-		memcpy(dst, e, replicas_entry_bytes(e));
-		bch2_replicas_entry_sort(dst);
+	for_each_replicas_entry(sb_r, src) {
+		struct bch_replicas_entry_cpu *dst = cpu_replicas_entry(cpu_r, idx++);
+		memcpy(&dst->e, src, replicas_entry_bytes(src));
+		bch2_replicas_entry_sort(&dst->e);
 	}
 
 	return 0;
@@ -469,9 +517,13 @@ __bch2_sb_replicas_v0_to_cpu_replicas(struct bch_sb_field_replicas_v0 *sb_r,
 		nr++;
 	}
 
+	entry_size = __cpu_replicas_entry_bytes(entry_size);
+
 	entry_size += sizeof(struct bch_replicas_entry_v1) -
 		sizeof(struct bch_replicas_entry_v0);
 
+	entry_size = round_up(entry_size, sizeof(atomic_t));
+
 	cpu_r->entries = kcalloc(nr, entry_size, GFP_KERNEL);
 	if (!cpu_r->entries)
 		return -BCH_ERR_ENOMEM_cpu_replicas;
@@ -480,14 +532,14 @@ __bch2_sb_replicas_v0_to_cpu_replicas(struct bch_sb_field_replicas_v0 *sb_r,
 	cpu_r->entry_size	= entry_size;
 
 	for_each_replicas_entry(sb_r, src) {
-		struct bch_replicas_entry_v1 *dst =
+		struct bch_replicas_entry_cpu *dst =
 			cpu_replicas_entry(cpu_r, idx++);
 
-		dst->data_type	= src->data_type;
-		dst->nr_devs	= src->nr_devs;
-		dst->nr_required = 1;
-		memcpy(dst->devs, src->devs, src->nr_devs);
-		bch2_replicas_entry_sort(dst);
+		dst->e.data_type	= src->data_type;
+		dst->e.nr_devs		= src->nr_devs;
+		dst->e.nr_required	= 1;
+		memcpy(dst->e.devs, src->devs, src->nr_devs);
+		bch2_replicas_entry_sort(&dst->e);
 	}
 
 	return 0;
@@ -495,6 +547,12 @@ __bch2_sb_replicas_v0_to_cpu_replicas(struct bch_sb_field_replicas_v0 *sb_r,
 
 int bch2_sb_replicas_to_cpu_replicas(struct bch_fs *c)
 {
+	/*
+	 * If called after fs is started (after journal read), we'll be blowing
+	 * away refcounts
+	 */
+	BUG_ON(test_bit(BCH_FS_started, &c->flags));
+
 	struct bch_sb_field_replicas *sb_v1;
 	struct bch_sb_field_replicas_v0 *sb_v0;
 	CLASS(bch_replicas_cpu, new_r)();
@@ -522,7 +580,7 @@ static int bch2_cpu_replicas_to_sb_replicas_v0(struct bch_fs *c,
 	bytes = sizeof(struct bch_sb_field_replicas);
 
 	for_each_cpu_replicas_entry(r, src)
-		bytes += replicas_entry_bytes(src) - 1;
+		bytes += replicas_entry_bytes(&src->e) - 1;
 
 	sb_r = bch2_sb_field_resize(&c->disk_sb, replicas_v0,
 			DIV_ROUND_UP(bytes, sizeof(u64)));
@@ -538,9 +596,9 @@ static int bch2_cpu_replicas_to_sb_replicas_v0(struct bch_fs *c,
 
 	dst = sb_r->entries;
 	for_each_cpu_replicas_entry(r, src) {
-		dst->data_type	= src->data_type;
-		dst->nr_devs	= src->nr_devs;
-		memcpy(dst->devs, src->devs, src->nr_devs);
+		dst->data_type	= src->e.data_type;
+		dst->nr_devs	= src->e.nr_devs;
+		memcpy(dst->devs, src->e.devs, src->e.nr_devs);
 
 		dst = replicas_entry_next(dst);
 
@@ -561,8 +619,8 @@ static int bch2_cpu_replicas_to_sb_replicas(struct bch_fs *c,
 	bytes = sizeof(struct bch_sb_field_replicas);
 
 	for_each_cpu_replicas_entry(r, src) {
-		bytes += replicas_entry_bytes(src);
-		if (src->nr_required != 1)
+		bytes += replicas_entry_bytes(&src->e);
+		if (src->e.nr_required != 1)
 			need_v1 = true;
 	}
 
@@ -583,7 +641,7 @@ static int bch2_cpu_replicas_to_sb_replicas(struct bch_fs *c,
 
 	dst = sb_r->entries;
 	for_each_cpu_replicas_entry(r, src) {
-		memcpy(dst, src, replicas_entry_bytes(src));
+		memcpy(dst, &src->e, replicas_entry_bytes(&src->e));
 
 		dst = replicas_entry_next(dst);
 
@@ -602,24 +660,26 @@ static int bch2_cpu_replicas_validate(struct bch_replicas_cpu *cpu_r,
 	sort_r(cpu_r->entries,
 	       cpu_r->nr,
 	       cpu_r->entry_size,
-	       bch2_memcmp, NULL,
+	       cpu_replicas_entry_cmp_r, NULL,
 	       (void *)(size_t)cpu_r->entry_size);
 
 	for (i = 0; i < cpu_r->nr; i++) {
-		struct bch_replicas_entry_v1 *e =
+		struct bch_replicas_entry_cpu *e =
 			cpu_replicas_entry(cpu_r, i);
 
-		try(bch2_replicas_entry_sb_validate(e, sb, err));
+		try(bch2_replicas_entry_sb_validate(&e->e, sb, err));
 
 		if (i + 1 < cpu_r->nr) {
-			struct bch_replicas_entry_v1 *n =
+			struct bch_replicas_entry_cpu *n =
 				cpu_replicas_entry(cpu_r, i + 1);
 
-			BUG_ON(memcmp(e, n, cpu_r->entry_size) > 0);
+			int cmp = cpu_replicas_entry_cmp(e, n, cpu_r->entry_size);
 
-			if (!memcmp(e, n, cpu_r->entry_size)) {
+			BUG_ON(cmp > 0);
+
+			if (!cmp) {
 				prt_printf(err, "duplicate replicas entry ");
-				bch2_replicas_entry_to_text(err, e);
+				bch2_replicas_entry_to_text(err, &e->e);
 				return -BCH_ERR_invalid_sb_replicas;
 			}
 		}
@@ -702,7 +762,9 @@ bool bch2_can_read_fs_with_devs(struct bch_fs *c, struct bch_devs_mask devs,
 				unsigned flags, struct printbuf *err)
 {
 	guard(percpu_read)(&c->mark_lock);
-	for_each_cpu_replicas_entry(&c->replicas, e) {
+	for_each_cpu_replicas_entry(&c->replicas, i) {
+		struct bch_replicas_entry_v1 *e = &i->e;
+
 		unsigned nr_online = 0, nr_failed = 0, dflags = 0;
 		bool metadata = e->data_type < BCH_DATA_user;
 
@@ -820,6 +882,25 @@ bool bch2_have_enough_devs(struct bch_fs *c, struct bch_devs_mask devs,
 	return bch2_can_read_fs_with_devs(c, devs, flags, err);
 }
 
+bool bch2_sb_has_journal(struct bch_sb *sb)
+{
+	struct bch_sb_field_replicas *replicas = bch2_sb_field_get(sb, replicas);
+	struct bch_sb_field_replicas_v0 *replicas_v0 = bch2_sb_field_get(sb, replicas_v0);
+
+	if (replicas) {
+		for_each_replicas_entry(replicas, r)
+			if (r->data_type == BCH_DATA_journal)
+				return true;
+	} else if (replicas_v0) {
+		for_each_replicas_entry(replicas_v0, r)
+			if (r->data_type == BCH_DATA_journal)
+				return true;
+	}
+
+
+	return false;
+}
+
 unsigned bch2_sb_dev_has_data(struct bch_sb *sb, unsigned dev)
 {
 	struct bch_sb_field_replicas *replicas;
@@ -863,5 +944,4 @@ unsigned bch2_dev_has_data(struct bch_fs *c, struct bch_dev *ca)
 void bch2_fs_replicas_exit(struct bch_fs *c)
 {
 	kfree(c->replicas.entries);
-	kfree(c->replicas_gc.entries);
 }
diff --git a/libbcachefs/alloc/replicas.h b/libbcachefs/alloc/replicas.h
index b2b86089..f9743ec5 100644
--- a/libbcachefs/alloc/replicas.h
+++ b/libbcachefs/alloc/replicas.h
@@ -39,13 +39,22 @@ bool bch2_can_read_fs_with_devs(struct bch_fs *, struct bch_devs_mask,
 bool bch2_have_enough_devs(struct bch_fs *, struct bch_devs_mask,
 			   unsigned, struct printbuf *, bool);
 
+bool bch2_sb_has_journal(struct bch_sb *);
 unsigned bch2_sb_dev_has_data(struct bch_sb *, unsigned);
 unsigned bch2_dev_has_data(struct bch_fs *, struct bch_dev *);
 
-int bch2_replicas_gc_end(struct bch_fs *, int);
-int bch2_replicas_gc_start(struct bch_fs *, unsigned);
+void bch2_replicas_entry_put_many(struct bch_fs *, struct bch_replicas_entry_v1 *, unsigned);
+static inline void bch2_replicas_entry_put(struct bch_fs *c, struct bch_replicas_entry_v1 *r)
+{
+	bch2_replicas_entry_put_many(c, r, 1);
+}
+
+int bch2_replicas_entry_get(struct bch_fs *, struct bch_replicas_entry_v1 *);
+
 void bch2_replicas_entry_kill(struct bch_fs *, struct bch_replicas_entry_v1 *);
 
+int bch2_replicas_gc_reffed(struct bch_fs *);
+
 static inline bool bch2_replicas_entry_has_dev(struct bch_replicas_entry_v1 *r, unsigned dev)
 {
 	for (unsigned i = 0; i < r->nr_devs; i++)
@@ -54,6 +63,12 @@ static inline bool bch2_replicas_entry_has_dev(struct bch_replicas_entry_v1 *r,
 	return false;
 }
 
+static inline bool bch2_replicas_entry_eq(struct bch_replicas_entry_v1 *l,
+					  struct bch_replicas_entry_v1 *r)
+{
+	return l->nr_devs == r->nr_devs && !memcmp(l, r, replicas_entry_bytes(l));
+}
+
 /* iterate over superblock replicas - used by userspace tools: */
 
 #define replicas_entry_next(_i)						\
diff --git a/libbcachefs/alloc/replicas_types.h b/libbcachefs/alloc/replicas_types.h
index 418e702e..50d8f87c 100644
--- a/libbcachefs/alloc/replicas_types.h
+++ b/libbcachefs/alloc/replicas_types.h
@@ -2,10 +2,16 @@
 #ifndef _BCACHEFS_REPLICAS_TYPES_H
 #define _BCACHEFS_REPLICAS_TYPES_H
 
+/* unsized - bch_replicas_entry_v1 is variable length */
+struct bch_replicas_entry_cpu {
+	atomic_t			ref;
+	struct bch_replicas_entry_v1	e;
+};
+
 struct bch_replicas_cpu {
-	unsigned		nr;
-	unsigned		entry_size;
-	struct bch_replicas_entry_v1 *entries;
+	unsigned			nr;
+	unsigned			entry_size;
+	struct bch_replicas_entry_cpu	*entries;
 };
 
 union bch_replicas_padded {
diff --git a/libbcachefs/bcachefs.h b/libbcachefs/bcachefs.h
index 8539b4e1..9fd7a62e 100644
--- a/libbcachefs/bcachefs.h
+++ b/libbcachefs/bcachefs.h
@@ -808,8 +808,6 @@ struct bch_fs {
 	struct bch_accounting_mem accounting;
 
 	struct bch_replicas_cpu replicas;
-	struct bch_replicas_cpu replicas_gc;
-	struct mutex		replicas_gc_lock;
 
 	struct journal_entry_res btree_root_journal_res;
 	struct journal_entry_res clock_journal_res;
diff --git a/libbcachefs/btree/key_cache.c b/libbcachefs/btree/key_cache.c
index 0532e9a9..f2e213d2 100644
--- a/libbcachefs/btree/key_cache.c
+++ b/libbcachefs/btree/key_cache.c
@@ -438,10 +438,10 @@ static int btree_key_cache_flush_pos(struct btree_trans *trans,
 		 * sequence number with a new btree node write, we want to re-journal
 		 * the update
 		 */
-		if (ck->journal.seq == journal_last_seq(j))
+		if (ck->journal.seq == j->last_seq)
 			commit_flags |= BCH_WATERMARK_reclaim;
 
-		if (ck->journal.seq != journal_last_seq(j) ||
+		if (ck->journal.seq != j->last_seq ||
 		    !journal_low_on_space(&c->journal))
 			commit_flags |= BCH_TRANS_COMMIT_no_journal_res;
 
diff --git a/libbcachefs/data/extents.c b/libbcachefs/data/extents.c
index 93fe7b74..4d7f7287 100644
--- a/libbcachefs/data/extents.c
+++ b/libbcachefs/data/extents.c
@@ -598,31 +598,16 @@ static inline bool bch2_crc_unpacked_cmp(struct bch_extent_crc_unpacked l,
 		bch2_crc_cmp(l.csum, r.csum));
 }
 
-static inline bool can_narrow_crc(struct bch_extent_crc_unpacked u,
-				  struct bch_extent_crc_unpacked n)
+static union bch_extent_entry *bkey_crc_find(struct bkey_i *k, struct bch_extent_crc_unpacked crc)
 {
-	return !crc_is_compressed(u) &&
-		u.csum_type &&
-		u.uncompressed_size > u.live_size &&
-		bch2_csum_type_is_encryption(u.csum_type) ==
-		bch2_csum_type_is_encryption(n.csum_type);
-}
+	struct bkey_ptrs ptrs = bch2_bkey_ptrs(bkey_i_to_s(k));
+	struct bch_extent_crc_unpacked i;
+	union bch_extent_entry *entry;
 
-bool bch2_can_narrow_extent_crcs(struct bkey_s_c k,
-				 struct bch_extent_crc_unpacked n)
-{
-	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
-	struct bch_extent_crc_unpacked crc;
-	const union bch_extent_entry *i;
-
-	if (!n.csum_type)
-		return false;
-
-	bkey_for_each_crc(k.k, ptrs, crc, i)
-		if (can_narrow_crc(crc, n))
-			return true;
-
-	return false;
+	bkey_for_each_crc(&k->k, ptrs, i, entry)
+		if (!bch2_crc_unpacked_cmp(i, crc))
+			return entry;
+	return NULL;
 }
 
 /*
@@ -634,44 +619,31 @@ bool bch2_can_narrow_extent_crcs(struct bkey_s_c k,
  * currently live (so that readers won't have to bounce) while we've got the
  * checksum we need:
  */
-bool bch2_bkey_narrow_crcs(struct bkey_i *k, struct bch_extent_crc_unpacked n)
+bool bch2_bkey_narrow_crc(struct bkey_i *k,
+			  struct bch_extent_crc_unpacked old,
+			  struct bch_extent_crc_unpacked new)
 {
-	struct bkey_ptrs ptrs = bch2_bkey_ptrs(bkey_i_to_s(k));
-	struct bch_extent_crc_unpacked u;
-	struct extent_ptr_decoded p;
-	union bch_extent_entry *i;
-	bool ret = false;
+	BUG_ON(crc_is_compressed(new));
+	BUG_ON(new.offset);
+	BUG_ON(new.live_size != k->k.size);
 
-	/* Find a checksum entry that covers only live data: */
-	if (!n.csum_type) {
-		bkey_for_each_crc(&k->k, ptrs, u, i)
-			if (!crc_is_compressed(u) &&
-			    u.csum_type &&
-			    u.live_size == u.uncompressed_size) {
-				n = u;
-				goto found;
-			}
+
+	union bch_extent_entry *old_e = bkey_crc_find(k, old);
+	if (!old_e)
 		return false;
+
+	struct bkey_ptrs ptrs = bch2_bkey_ptrs(bkey_i_to_s(k));
+	union bch_extent_entry *i;
+
+	bkey_extent_entry_for_each_from(ptrs, i, extent_entry_next(old_e)) {
+		if (extent_entry_is_crc(i))
+			break;
+		if (extent_entry_is_ptr(i))
+			i->ptr.offset += old.offset;
 	}
-found:
-	BUG_ON(crc_is_compressed(n));
-	BUG_ON(n.offset);
-	BUG_ON(n.live_size != k->k.size);
 
-restart_narrow_pointers:
-	ptrs = bch2_bkey_ptrs(bkey_i_to_s(k));
-
-	bkey_for_each_ptr_decode(&k->k, ptrs, p, i)
-		if (can_narrow_crc(p.crc, n)) {
-			bch2_bkey_drop_ptr_noerror(bkey_i_to_s(k), &i->ptr);
-			p.ptr.offset += p.crc.offset;
-			p.crc = n;
-			bch2_extent_ptr_decoded_append(k, &p);
-			ret = true;
-			goto restart_narrow_pointers;
-		}
-
-	return ret;
+	bch2_extent_crc_pack(entry_to_crc(old_e), new, extent_entry_type(old_e));
+	return true;
 }
 
 static void bch2_extent_crc_pack(union bch_extent_crc *dst,
diff --git a/libbcachefs/data/extents.h b/libbcachefs/data/extents.h
index 286afa94..82844873 100644
--- a/libbcachefs/data/extents.h
+++ b/libbcachefs/data/extents.h
@@ -461,9 +461,9 @@ bool bch2_reservation_merge(struct bch_fs *, struct bkey_s, struct bkey_s_c);
 
 /* Extent checksum entries: */
 
-bool bch2_can_narrow_extent_crcs(struct bkey_s_c,
-				 struct bch_extent_crc_unpacked);
-bool bch2_bkey_narrow_crcs(struct bkey_i *, struct bch_extent_crc_unpacked);
+bool bch2_bkey_narrow_crc(struct bkey_i *,
+			  struct bch_extent_crc_unpacked,
+			  struct bch_extent_crc_unpacked);
 void bch2_extent_crc_append(struct bkey_i *,
 			    struct bch_extent_crc_unpacked);
 
diff --git a/libbcachefs/data/read.c b/libbcachefs/data/read.c
index 4ebd9971..53b1295d 100644
--- a/libbcachefs/data/read.c
+++ b/libbcachefs/data/read.c
@@ -784,7 +784,7 @@ static int __bch2_rbio_narrow_crcs(struct btree_trans *trans,
 
 	bkey_reassemble(new, k);
 
-	if (!bch2_bkey_narrow_crcs(new, *new_crc))
+	if (!bch2_bkey_narrow_crc(new, rbio->pick.crc, *new_crc))
 		return bch_err_throw(c, rbio_narrow_crcs_fail);
 
 	return bch2_trans_update(trans, &iter, new, BTREE_UPDATE_internal_snapshot_node);
@@ -794,7 +794,8 @@ static noinline void bch2_rbio_narrow_crcs(struct bch_read_bio *rbio)
 {
 	struct bch_fs *c = rbio->c;
 
-	if (crc_is_compressed(rbio->pick.crc))
+	if (!rbio->pick.crc.csum_type ||
+	    crc_is_compressed(rbio->pick.crc))
 		return;
 
 	u64 data_offset = rbio->data_pos.offset - rbio->pick.crc.offset;
@@ -1070,6 +1071,13 @@ static noinline void read_from_stale_dirty_pointer(struct btree_trans *trans,
 	bch2_fs_inconsistent(c, "%s", buf.buf);
 }
 
+static inline bool can_narrow_crc(struct bch_extent_crc_unpacked n)
+{
+	return n.csum_type &&
+		n.uncompressed_size < n.live_size &&
+		!crc_is_compressed(n);
+}
+
 int __bch2_read_extent(struct btree_trans *trans, struct bch_read_bio *orig,
 		       struct bvec_iter iter, struct bpos read_pos,
 		       enum btree_id data_btree, struct bkey_s_c k,
@@ -1170,8 +1178,7 @@ retry_pick:
 		    bio_flagged(&orig->bio, BIO_CHAIN))
 			flags |= BCH_READ_must_clone;
 
-		narrow_crcs = !(flags & BCH_READ_in_retry) &&
-			bch2_can_narrow_extent_crcs(k, pick.crc);
+		narrow_crcs = !(flags & BCH_READ_in_retry) && can_narrow_crc(pick.crc);
 
 		if (narrow_crcs && (flags & BCH_READ_user_mapped))
 			flags |= BCH_READ_must_bounce;
diff --git a/libbcachefs/data/update.c b/libbcachefs/data/update.c
index a636b0c1..7f508674 100644
--- a/libbcachefs/data/update.c
+++ b/libbcachefs/data/update.c
@@ -298,7 +298,6 @@ restart_drop_extra_replicas:
 		extent_for_each_ptr_decode(extent_i_to_s(new), p, entry)
 			bch2_extent_ptr_decoded_append(insert, &p);
 
-		bch2_bkey_narrow_crcs(insert, (struct bch_extent_crc_unpacked) { 0 });
 		bch2_bkey_drop_extra_cached_ptrs(c, &m->op.opts, bkey_i_to_s(insert));
 
 		ret = bch2_sum_sector_overwrites(trans, &iter, insert,
@@ -784,6 +783,53 @@ static int can_write_extent(struct bch_fs *c, struct data_update *m)
 	return 0;
 }
 
+/*
+ * When an extent has both checksummed and non-checksummed pointers, special
+ * handling:
+ *
+ * We don't want to blindly apply an existing checksum to non-checksummed data,
+ * or lose our ability to detect that different replicas in the same extent have
+ * or had different data, so:
+ *
+ * - prefer to read from the specific replica being rewritten
+ * - if we're rewriting a replica without a checksum, only rewrite that specific
+ *   replica in this data update
+ */
+static void checksummed_and_non_checksummed_handling(struct data_update *u, struct bkey_ptrs_c ptrs)
+{
+	bool have_checksummed = false, have_non_checksummed = false;
+
+	struct bkey_s_c k = bkey_i_to_s_c(u->k.k);
+	const union bch_extent_entry *entry;
+	struct extent_ptr_decoded p;
+	bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
+		if (p.crc.csum_type)
+			have_checksummed = true;
+		else
+			have_non_checksummed = true;
+	}
+
+	if (unlikely(have_checksummed && have_non_checksummed)) {
+		unsigned ptr_bit = 1;
+		int rewrite_checksummed = -1;
+
+		bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
+			if (ptr_bit & u->opts.ptrs_rewrite) {
+				if (rewrite_checksummed < 0) {
+					rewrite_checksummed = p.crc.csum_type != 0;
+					u->opts.read_dev = p.ptr.dev;
+				}
+
+				if (rewrite_checksummed != (p.crc.csum_type != 0) ||
+				    (!rewrite_checksummed && p.ptr.dev != u->opts.read_dev))
+					u->opts.ptrs_rewrite &= ~ptr_bit;
+			}
+
+			ptr_bit <<= 1;
+		}
+	}
+}
+
 int bch2_data_update_init(struct btree_trans *trans,
 			  struct btree_iter *iter,
 			  struct moving_context *ctxt,
@@ -844,6 +890,9 @@ int bch2_data_update_init(struct btree_trans *trans,
 	unsigned buf_bytes = 0;
 	bool unwritten = false;
 
+	if (m->opts.ptrs_rewrite)
+		checksummed_and_non_checksummed_handling(m, ptrs);
+
 	scoped_guard(rcu) {
 		unsigned ptr_bit = 1;
 		bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
@@ -957,6 +1006,11 @@ int bch2_data_update_init(struct btree_trans *trans,
 		}
 	}
 
+	/*
+	 * Check if we have checksummed and non-checksummed pointers, prefer to
+	 * read from the pointer we're operating on
+	 */
+
 	m->ptrs_held = bkey_get_dev_refs(c, k);
 
 	if (c->opts.nocow_enabled) {
diff --git a/libbcachefs/errcode.h b/libbcachefs/errcode.h
index 5fbda02e..d11a1a45 100644
--- a/libbcachefs/errcode.h
+++ b/libbcachefs/errcode.h
@@ -226,6 +226,7 @@
 	x(EINVAL,			erasure_coding_found_btree_node)	\
 	x(EINVAL,			option_negative)			\
 	x(EINVAL,			topology_repair)			\
+	x(EINVAL,			unaligned_io)				\
 	x(BCH_ERR_topology_repair,	topology_repair_drop_this_node)		\
 	x(BCH_ERR_topology_repair,	topology_repair_drop_prev_node)		\
 	x(BCH_ERR_topology_repair,	topology_repair_did_fill_from_scan)	\
diff --git a/libbcachefs/init/fs.c b/libbcachefs/init/fs.c
index 1ea8c224..594263a4 100644
--- a/libbcachefs/init/fs.c
+++ b/libbcachefs/init/fs.c
@@ -375,9 +375,6 @@ void bch2_fs_read_only(struct bch_fs *c)
 		BUG_ON(c->btree_write_buffer.inc.keys.nr);
 		BUG_ON(c->btree_write_buffer.flushing.keys.nr);
 		bch2_verify_accounting_clean(c);
-
-		bch_verbose(c, "marking filesystem clean");
-		bch2_fs_mark_clean(c);
 	} else {
 		/* Make sure error counts/counters are persisted */
 		guard(mutex)(&c->sb_lock);
@@ -473,7 +470,6 @@ static int __bch2_fs_read_write(struct bch_fs *c, bool early)
 
 	try(bch2_fs_init_rw(c));
 	try(bch2_sb_members_v2_init(c));
-	try(bch2_fs_mark_dirty(c));
 
 	clear_bit(BCH_FS_clean_shutdown, &c->flags);
 
@@ -918,7 +914,7 @@ static int bch2_fs_opt_version_init(struct bch_fs *c)
 	}
 
 	if (c->sb.version_incompat_allowed != c->sb.version) {
-		prt_printf(&p, "\nallowing incompatible features above ");
+		prt_printf(&p, "\nallowing incompatible features up to ");
 		bch2_version_to_text(&p, c->sb.version_incompat_allowed);
 	}
 
@@ -1052,7 +1048,6 @@ static int bch2_fs_init(struct bch_fs *c, struct bch_sb *sb,
 
 	init_rwsem(&c->state_lock);
 	mutex_init(&c->sb_lock);
-	mutex_init(&c->replicas_gc_lock);
 	mutex_init(&c->btree_root_lock);
 	INIT_WORK(&c->read_only_work, bch2_fs_read_only_work);
 
diff --git a/libbcachefs/init/recovery.c b/libbcachefs/init/recovery.c
index b001065b..25cdb194 100644
--- a/libbcachefs/init/recovery.c
+++ b/libbcachefs/init/recovery.c
@@ -610,8 +610,7 @@ fsck_err:
 int bch2_fs_recovery(struct bch_fs *c)
 {
 	struct bch_sb_field_clean *clean = NULL;
-	struct jset *last_journal_entry = NULL;
-	u64 last_seq = 0, blacklist_seq, journal_seq;
+	struct journal_start_info journal_start = {};
 	int ret = 0;
 
 	if (c->sb.clean) {
@@ -637,7 +636,7 @@ int bch2_fs_recovery(struct bch_fs *c)
 		struct journal_replay **i;
 
 		bch_verbose(c, "starting journal read");
-		ret = bch2_journal_read(c, &last_seq, &blacklist_seq, &journal_seq);
+		ret = bch2_journal_read(c, &journal_start);
 		if (ret)
 			goto err;
 
@@ -648,22 +647,21 @@ int bch2_fs_recovery(struct bch_fs *c)
 		if (c->opts.read_journal_only)
 			goto out;
 
+		if (mustfix_fsck_err_on(c->sb.clean && !journal_start.clean,
+					c, clean_but_journal_not_empty,
+					"filesystem marked clean but journal not empty")) {
+			c->sb.compat &= ~(1ULL << BCH_COMPAT_alloc_info);
+			SET_BCH_SB_CLEAN(c->disk_sb.sb, false);
+			c->sb.clean = false;
+		}
+
+		struct jset *last_journal_entry = NULL;
 		genradix_for_each_reverse(&c->journal_entries, iter, i)
 			if (!journal_replay_ignore(*i)) {
 				last_journal_entry = &(*i)->j;
 				break;
 			}
 
-		if (mustfix_fsck_err_on(c->sb.clean &&
-					last_journal_entry &&
-					!journal_entry_empty(last_journal_entry), c,
-				clean_but_journal_not_empty,
-				"filesystem marked clean but journal not empty")) {
-			c->sb.compat &= ~(1ULL << BCH_COMPAT_alloc_info);
-			SET_BCH_SB_CLEAN(c->disk_sb.sb, false);
-			c->sb.clean = false;
-		}
-
 		if (!last_journal_entry) {
 			fsck_err_on(!c->sb.clean, c,
 				    dirty_but_no_journal_entries,
@@ -705,11 +703,12 @@ use_clean:
 			goto err;
 
 		}
-		blacklist_seq = journal_seq = le64_to_cpu(clean->journal_seq) + 1;
+
+		journal_start.start_seq = le64_to_cpu(clean->journal_seq) + 1;
 	}
 
-	c->journal_replay_seq_start	= last_seq;
-	c->journal_replay_seq_end	= blacklist_seq - 1;
+	c->journal_replay_seq_start	= journal_start.seq_read_start;
+	c->journal_replay_seq_end	= journal_start.seq_read_end;
 
 	zero_out_btree_mem_ptr(&c->journal_keys);
 
@@ -756,13 +755,15 @@ use_clean:
 	 * journal sequence numbers:
 	 */
 	if (!c->sb.clean)
-		journal_seq += JOURNAL_BUF_NR * 4;
+		journal_start.start_seq += JOURNAL_BUF_NR * 4;
 
-	if (blacklist_seq != journal_seq) {
+	if (journal_start.seq_read_end &&
+	    journal_start.seq_read_end + 1 != journal_start.start_seq) {
+		u64 blacklist_seq = journal_start.seq_read_end + 1;
 		ret =   bch2_journal_log_msg(c, "blacklisting entries %llu-%llu",
-					     blacklist_seq, journal_seq) ?:
+					     blacklist_seq, journal_start.start_seq) ?:
 			bch2_journal_seq_blacklist_add(c,
-					blacklist_seq, journal_seq);
+					blacklist_seq, journal_start.start_seq);
 		if (ret) {
 			bch_err_msg(c, ret, "error creating new journal seq blacklist entry");
 			goto err;
@@ -770,8 +771,10 @@ use_clean:
 	}
 
 	ret =   bch2_journal_log_msg(c, "starting journal at entry %llu, replaying %llu-%llu",
-				     journal_seq, last_seq, blacklist_seq - 1) ?:
-		bch2_fs_journal_start(&c->journal, last_seq, journal_seq);
+				     journal_start.start_seq,
+				     journal_start.seq_read_start,
+				     journal_start.seq_read_end) ?:
+		bch2_fs_journal_start(&c->journal, journal_start);
 	if (ret)
 		goto err;
 
@@ -1014,7 +1017,8 @@ 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:
 	 */
-	ret = bch2_fs_journal_start(&c->journal, 1, 1);
+	struct journal_start_info journal_start = { .start_seq = 1 };
+	ret = bch2_fs_journal_start(&c->journal, journal_start);
 	if (ret)
 		goto err;
 
diff --git a/libbcachefs/journal/init.c b/libbcachefs/journal/init.c
index e7410baa..651228cc 100644
--- a/libbcachefs/journal/init.c
+++ b/libbcachefs/journal/init.c
@@ -11,6 +11,7 @@
 #include "alloc/foreground.h"
 #include "alloc/replicas.h"
 #include "btree/update.h"
+#include "init/error.h"
 
 /* allocate journal on a device: */
 
@@ -367,29 +368,30 @@ void bch2_fs_journal_stop(struct journal *j)
 		clear_bit(JOURNAL_running, &j->flags);
 }
 
-int bch2_fs_journal_start(struct journal *j, u64 last_seq, u64 cur_seq)
+int bch2_fs_journal_start(struct journal *j, struct journal_start_info info)
 {
 	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;
+	int ret = 0;
 
 	/*
 	 *
 	 * XXX pick most recent non blacklisted sequence number
 	 */
 
-	cur_seq = max(cur_seq, bch2_journal_last_blacklisted_seq(c));
+	info.start_seq = max(info.start_seq, bch2_journal_last_blacklisted_seq(c));
 
-	if (cur_seq >= JOURNAL_SEQ_MAX) {
+	if (info.start_seq >= JOURNAL_SEQ_MAX) {
 		bch_err(c, "cannot start: journal seq overflow");
 		return -EINVAL;
 	}
 
 	/* Clean filesystem? */
-	if (!last_seq)
-		last_seq = cur_seq;
+	u64 cur_seq	= info.start_seq;
+	u64 last_seq	= info.seq_read_start ?: info.start_seq;
 
 	u64 nr = cur_seq - last_seq;
 	if (nr * sizeof(struct journal_entry_pin_list) > 1U << 30) {
@@ -419,6 +421,7 @@ int bch2_fs_journal_start(struct journal *j, u64 last_seq, u64 cur_seq)
 	j->seq_write_started	= cur_seq - 1;
 	j->seq_ondisk		= cur_seq - 1;
 	j->pin.front		= last_seq;
+	j->last_seq		= last_seq;
 	j->pin.back		= cur_seq;
 	atomic64_set(&j->seq, cur_seq - 1);
 
@@ -441,12 +444,26 @@ int bch2_fs_journal_start(struct journal *j, u64 last_seq, u64 cur_seq)
 		if (journal_entry_empty(&i->j))
 			j->last_empty_seq = le64_to_cpu(i->j.seq);
 
-		struct bch_devs_list seq_devs = {};
-		darray_for_each(i->ptrs, ptr)
-			seq_devs.data[seq_devs.nr++] = ptr->dev;
+		if (!info.clean) {
+			struct bch_devs_list seq_devs = {};
+			darray_for_each(i->ptrs, ptr)
+				seq_devs.data[seq_devs.nr++] = ptr->dev;
 
-		p = journal_seq_pin(j, seq);
-		bch2_devlist_to_replicas(&p->devs.e, BCH_DATA_journal, seq_devs);
+			p = journal_seq_pin(j, seq);
+			bch2_devlist_to_replicas(&p->devs.e, BCH_DATA_journal, seq_devs);
+
+			CLASS(printbuf, buf)();
+			bch2_replicas_entry_to_text(&buf, &p->devs.e);
+
+			fsck_err_on(!test_bit(JOURNAL_degraded, &j->flags) &&
+				    !bch2_replicas_marked(c, &p->devs.e),
+				    c, journal_entry_replicas_not_marked,
+				    "superblock not marked as containing replicas for journal entry %llu\n%s",
+				    le64_to_cpu(i->j.seq), buf.buf);
+
+			if (bch2_replicas_entry_get(c, &p->devs.e))
+				p->devs.e.nr_devs = 0;
+		}
 
 		had_entries = true;
 	}
@@ -460,7 +477,9 @@ int bch2_fs_journal_start(struct journal *j, u64 last_seq, u64 cur_seq)
 		c->last_bucket_seq_cleanup = journal_cur_seq(j);
 	}
 
-	return 0;
+	try(bch2_replicas_gc_reffed(c));
+fsck_err:
+	return ret;
 }
 
 void bch2_journal_set_replay_done(struct journal *j)
@@ -585,6 +604,7 @@ void bch2_fs_journal_init_early(struct journal *j)
 	init_waitqueue_head(&j->reclaim_wait);
 	init_waitqueue_head(&j->pin_flush_wait);
 	mutex_init(&j->reclaim_lock);
+	mutex_init(&j->last_seq_ondisk_lock);
 	mutex_init(&j->discard_lock);
 
 	lockdep_init_map(&j->res_map, "journal res", &res_key, 0);
diff --git a/libbcachefs/journal/init.h b/libbcachefs/journal/init.h
index 6d49c29a..6fc55c50 100644
--- a/libbcachefs/journal/init.h
+++ b/libbcachefs/journal/init.h
@@ -11,7 +11,7 @@ int bch2_fs_journal_alloc(struct bch_fs *);
 void bch2_dev_journal_stop(struct journal *, struct bch_dev *);
 
 void bch2_fs_journal_stop(struct journal *);
-int bch2_fs_journal_start(struct journal *, u64, u64);
+int bch2_fs_journal_start(struct journal *, struct journal_start_info);
 void bch2_journal_set_replay_done(struct journal *);
 
 void bch2_dev_journal_exit(struct bch_dev *);
diff --git a/libbcachefs/journal/journal.c b/libbcachefs/journal/journal.c
index 2b167bf8..1c1d3472 100644
--- a/libbcachefs/journal/journal.c
+++ b/libbcachefs/journal/journal.c
@@ -187,7 +187,7 @@ 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_update_last_seq(j);
 	bch2_journal_do_writes(j);
 
 	/*
@@ -235,10 +235,10 @@ static void __journal_entry_close(struct journal *j, unsigned closed_val, bool t
 	/* Close out old buffer: */
 	buf->data->u64s		= cpu_to_le32(old.cur_entry_offset);
 
-	struct journal_entry_pin_list *pin_list =
-		journal_seq_pin(j, journal_cur_seq(j));
-	pin_list->bytes = roundup_pow_of_two(vstruct_bytes(buf->data));
-	j->dirty_entry_bytes += pin_list->bytes;
+	size_t bytes = roundup_pow_of_two(vstruct_bytes(buf->data));
+
+	journal_seq_pin(j, journal_cur_seq(j))->bytes = bytes;
+	j->dirty_entry_bytes += bytes;
 
 	if (trace_journal_entry_close_enabled() && trace) {
 		CLASS(printbuf, err)();
@@ -280,7 +280,7 @@ static void __journal_entry_close(struct journal *j, unsigned closed_val, bool t
 	 * 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
+	 * After the old pin is dropped j->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.
 	 *
@@ -291,7 +291,7 @@ static void __journal_entry_close(struct journal *j, unsigned closed_val, bool t
 	 * 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->last_seq		= j->last_seq;
 	buf->data->last_seq	= cpu_to_le64(buf->last_seq);
 	BUG_ON(buf->last_seq > le64_to_cpu(buf->data->seq));
 
@@ -358,7 +358,6 @@ static int journal_entry_open(struct journal *j)
 
 	lockdep_assert_held(&j->lock);
 	BUG_ON(journal_entry_is_open(j));
-	BUG_ON(c->sb.clean);
 
 	if (j->blocked)
 		return bch_err_throw(c, journal_blocked);
@@ -416,7 +415,7 @@ static int journal_entry_open(struct journal *j)
 
 	/*
 	 * The fifo_push() needs to happen at the same time as j->seq is
-	 * incremented for journal_last_seq() to be calculated correctly
+	 * incremented for j->last_seq to be calculated correctly
 	 */
 	atomic64_inc(&j->seq);
 	journal_pin_list_init(fifo_push_ref(&j->pin), 1);
@@ -1092,7 +1091,7 @@ void __bch2_journal_debug_to_text(struct printbuf *out, struct journal *j)
 	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:\t%llu\n",			j->last_seq);
 	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]);
diff --git a/libbcachefs/journal/journal.h b/libbcachefs/journal/journal.h
index 88e18364..272a3a64 100644
--- a/libbcachefs/journal/journal.h
+++ b/libbcachefs/journal/journal.h
@@ -129,11 +129,6 @@ static inline bool journal_low_on_space(struct journal *j)
 
 /* Sequence number of oldest dirty journal entry */
 
-static inline u64 journal_last_seq(struct journal *j)
-{
-	return j->pin.front;
-}
-
 static inline u64 journal_cur_seq(struct journal *j)
 {
 	return atomic64_read(&j->seq);
diff --git a/libbcachefs/journal/read.c b/libbcachefs/journal/read.c
index 2a697a23..4c5753b9 100644
--- a/libbcachefs/journal/read.c
+++ b/libbcachefs/journal/read.c
@@ -1346,18 +1346,17 @@ fsck_err:
 	return ret;
 }
 
-int bch2_journal_read(struct bch_fs *c,
-		      u64 *last_seq,
-		      u64 *blacklist_seq,
-		      u64 *start_seq)
+int bch2_journal_read(struct bch_fs *c, struct journal_start_info *info)
 {
 	struct journal_list jlist;
 	struct journal_replay *i, **_i;
 	struct genradix_iter radix_iter;
-	bool degraded = false, last_write_torn = false;
+	bool last_write_torn = false;
 	u64 seq;
 	int ret = 0;
 
+	memset(info, 0, sizeof(*info));
+
 	closure_init_stack(&jlist.cl);
 	mutex_init(&jlist.lock);
 	jlist.last_seq = 0;
@@ -1377,7 +1376,7 @@ int bch2_journal_read(struct bch_fs *c,
 				     system_unbound_wq,
 				     &jlist.cl);
 		else
-			degraded = true;
+			set_bit(JOURNAL_degraded, &c->journal.flags);
 	}
 
 	while (closure_sync_timeout(&jlist.cl, sysctl_hung_task_timeout_secs * HZ / 2))
@@ -1386,10 +1385,6 @@ int bch2_journal_read(struct bch_fs *c,
 	if (jlist.ret)
 		return jlist.ret;
 
-	*last_seq	= 0;
-	*start_seq	= 0;
-	*blacklist_seq	= 0;
-
 	/*
 	 * Find most recent flush entry, and ignore newer non flush entries -
 	 * those entries will be blacklisted:
@@ -1400,8 +1395,8 @@ int bch2_journal_read(struct bch_fs *c,
 		if (journal_replay_ignore(i))
 			continue;
 
-		if (!*start_seq)
-			*blacklist_seq = *start_seq = le64_to_cpu(i->j.seq) + 1;
+		if (!info->start_seq)
+			info->start_seq = le64_to_cpu(i->j.seq) + 1;
 
 		if (JSET_NO_FLUSH(&i->j)) {
 			i->ignore_blacklisted = true;
@@ -1426,27 +1421,28 @@ int bch2_journal_read(struct bch_fs *c,
 					 le64_to_cpu(i->j.seq)))
 			i->j.last_seq = i->j.seq;
 
-		*last_seq	= le64_to_cpu(i->j.last_seq);
-		*blacklist_seq	= le64_to_cpu(i->j.seq) + 1;
+		info->seq_read_start	= le64_to_cpu(i->j.last_seq);
+		info->seq_read_end	= le64_to_cpu(i->j.seq);
+		info->clean		= journal_entry_empty(&i->j);
 		break;
 	}
 
-	if (!*start_seq) {
+	if (!info->start_seq) {
 		bch_info(c, "journal read done, but no entries found");
 		return 0;
 	}
 
-	if (!*last_seq) {
+	if (!info->seq_read_end) {
 		fsck_err(c, dirty_but_no_journal_entries_post_drop_nonflushes,
 			 "journal read done, but no entries found after dropping non-flushes");
 		return 0;
 	}
 
-	u64 drop_before = *last_seq;
+	u64 drop_before = info->seq_read_start;
 	{
 		CLASS(printbuf, buf)();
 		prt_printf(&buf, "journal read done, replaying entries %llu-%llu",
-			   *last_seq, *blacklist_seq - 1);
+			   info->seq_read_start, info->seq_read_end);
 
 		/*
 		 * Drop blacklisted entries and entries older than last_seq (or start of
@@ -1457,9 +1453,11 @@ int bch2_journal_read(struct bch_fs *c,
 			prt_printf(&buf, " (rewinding from %llu)", c->opts.journal_rewind);
 		}
 
-		*last_seq = drop_before;
-		if (*start_seq != *blacklist_seq)
-			prt_printf(&buf, " (unflushed %llu-%llu)", *blacklist_seq, *start_seq - 1);
+		info->seq_read_start = drop_before;
+		if (info->seq_read_end + 1 != info->start_seq)
+			prt_printf(&buf, " (unflushed %llu-%llu)",
+				   info->seq_read_end + 1,
+				   info->start_seq - 1);
 		bch_info(c, "%s", buf.buf);
 	}
 
@@ -1483,7 +1481,7 @@ int bch2_journal_read(struct bch_fs *c,
 		}
 	}
 
-	try(bch2_journal_check_for_missing(c, drop_before, *blacklist_seq - 1));
+	try(bch2_journal_check_for_missing(c, drop_before, info->seq_read_end));
 
 	genradix_for_each(&c->journal_entries, radix_iter, _i) {
 		union bch_replicas_padded replicas = {
@@ -1516,17 +1514,6 @@ int bch2_journal_read(struct bch_fs *c,
 			replicas_entry_add_dev(&replicas.e, ptr->dev);
 
 		bch2_replicas_entry_sort(&replicas.e);
-
-		CLASS(printbuf, buf)();
-		bch2_replicas_entry_to_text(&buf, &replicas.e);
-
-		if (!degraded &&
-		    !bch2_replicas_marked(c, &replicas.e) &&
-		    (le64_to_cpu(i->j.seq) == *last_seq ||
-		     fsck_err(c, journal_entry_replicas_not_marked,
-			      "superblock not marked as containing replicas for journal entry %llu\n%s",
-			      le64_to_cpu(i->j.seq), buf.buf)))
-			try(bch2_mark_replicas(c, &replicas.e));
 	}
 fsck_err:
 	return ret;
diff --git a/libbcachefs/journal/read.h b/libbcachefs/journal/read.h
index ff3c8690..556a7ff1 100644
--- a/libbcachefs/journal/read.h
+++ b/libbcachefs/journal/read.h
@@ -70,6 +70,6 @@ struct u64_range {
 
 struct u64_range bch2_journal_entry_missing_range(struct bch_fs *, u64, u64);
 
-int bch2_journal_read(struct bch_fs *, u64 *, u64 *, u64 *);
+int bch2_journal_read(struct bch_fs *, struct journal_start_info *);
 
 #endif /* _BCACHEFS_JOURNAL_READ_H */
diff --git a/libbcachefs/journal/reclaim.c b/libbcachefs/journal/reclaim.c
index d15b54fc..703f626b 100644
--- a/libbcachefs/journal/reclaim.c
+++ b/libbcachefs/journal/reclaim.c
@@ -211,7 +211,7 @@ void bch2_journal_space_available(struct journal *j)
 			continue;
 
 		while (ja->dirty_idx != ja->cur_idx &&
-		       ja->bucket_seq[ja->dirty_idx] < journal_last_seq(j))
+		       ja->bucket_seq[ja->dirty_idx] < j->last_seq)
 			ja->dirty_idx = (ja->dirty_idx + 1) % ja->nr;
 
 		while (ja->dirty_idx_ondisk != ja->dirty_idx &&
@@ -325,37 +325,66 @@ void bch2_journal_do_discards(struct journal *j)
  * entry, holding it open to ensure it gets replayed during recovery:
  */
 
-void bch2_journal_reclaim_fast(struct journal *j)
+void bch2_journal_update_last_seq(struct journal *j)
 {
-	bool popped = false;
-
 	lockdep_assert_held(&j->lock);
 
 	/*
 	 * Unpin journal entries whose reference counts reached zero, meaning
 	 * all btree nodes got written out
 	 */
+	u64 old = j->last_seq;
 	struct journal_entry_pin_list *pin_list;
-	while (!fifo_empty(&j->pin) &&
-	       j->pin.front <= j->seq_ondisk &&
-	       !atomic_read(&(pin_list = &fifo_peek_front(&j->pin))->count)) {
+	while (j->last_seq <  j->pin.back &&
+	       j->last_seq <= j->seq_ondisk &&
+	       !atomic_read(&(pin_list = journal_seq_pin(j, j->last_seq))->count))
+		j->last_seq++;
 
-		if (WARN_ON(j->dirty_entry_bytes < pin_list->bytes))
-			pin_list->bytes = j->dirty_entry_bytes;
-
-		j->dirty_entry_bytes -= pin_list->bytes;
-		pin_list->bytes = 0;
-
-		j->pin.front++;
-		popped = true;
-	}
-
-	if (popped) {
+	if (old != j->last_seq) {
 		bch2_journal_space_available(j);
 		__closure_wake_up(&j->reclaim_flush_wait);
 	}
 }
 
+void bch2_journal_update_last_seq_ondisk(struct journal *j, u64 last_seq_ondisk)
+{
+	struct bch_fs *c = container_of(j, struct bch_fs, journal);
+	union bch_replicas_padded replicas;
+	unsigned nr_refs = 0;
+	size_t dirty_entry_bytes = 0;
+
+	scoped_guard(mutex, &j->last_seq_ondisk_lock)
+		while (j->last_seq_ondisk < last_seq_ondisk) {
+			struct journal_entry_pin_list *pin_list = journal_seq_pin(j, j->last_seq_ondisk);
+
+			if (pin_list->devs.e.nr_devs) {
+				if (nr_refs &&
+				    !bch2_replicas_entry_eq(&replicas.e, &pin_list->devs.e)) {
+					bch2_replicas_entry_put_many(c, &replicas.e, nr_refs);
+					nr_refs = 0;
+				}
+
+				memcpy(&replicas, &pin_list->devs, replicas_entry_bytes(&pin_list->devs.e));
+				pin_list->devs.e.nr_devs = 0;
+				nr_refs++;
+			}
+
+			dirty_entry_bytes += pin_list->bytes;
+			pin_list->bytes = 0;
+
+			j->last_seq_ondisk++;
+		}
+
+	scoped_guard(spinlock, &j->lock) {
+		if (WARN_ON(j->dirty_entry_bytes < dirty_entry_bytes))
+			dirty_entry_bytes = j->dirty_entry_bytes;
+		j->dirty_entry_bytes -= dirty_entry_bytes;
+	}
+
+	if (nr_refs)
+		bch2_replicas_entry_put_many(c, &replicas.e, nr_refs);
+}
+
 bool __bch2_journal_pin_put(struct journal *j, u64 seq)
 {
 	struct journal_entry_pin_list *pin_list = journal_seq_pin(j, seq);
@@ -367,7 +396,7 @@ void bch2_journal_pin_put(struct journal *j, u64 seq)
 {
 	if (__bch2_journal_pin_put(j, seq)) {
 		guard(spinlock)(&j->lock);
-		bch2_journal_reclaim_fast(j);
+		bch2_journal_update_last_seq(j);
 	}
 }
 
@@ -394,7 +423,7 @@ static inline bool __journal_pin_drop(struct journal *j,
 	 * writing a new last_seq will now make another bucket available:
 	 */
 	return atomic_dec_and_test(&pin_list->count) &&
-		pin_list == &fifo_peek_front(&j->pin);
+		pin_list == journal_seq_pin(j, j->last_seq);
 }
 
 void bch2_journal_pin_drop(struct journal *j,
@@ -402,7 +431,7 @@ void bch2_journal_pin_drop(struct journal *j,
 {
 	guard(spinlock)(&j->lock);
 	if (__journal_pin_drop(j, pin))
-		bch2_journal_reclaim_fast(j);
+		bch2_journal_update_last_seq(j);
 }
 
 static enum journal_pin_type journal_pin_type(struct journal_entry_pin *pin,
@@ -453,7 +482,7 @@ void bch2_journal_pin_copy(struct journal *j,
 
 	u64 seq = READ_ONCE(src->seq);
 
-	if (seq < journal_last_seq(j)) {
+	if (seq < j->last_seq) {
 		/*
 		 * bch2_journal_pin_copy() raced with bch2_journal_pin_drop() on
 		 * the src pin - with the pin dropped, the entry to pin might no
@@ -468,13 +497,13 @@ void bch2_journal_pin_copy(struct journal *j,
 	bch2_journal_pin_set_locked(j, seq, dst, flush_fn, journal_pin_type(dst, flush_fn));
 
 	if (reclaim)
-		bch2_journal_reclaim_fast(j);
+		bch2_journal_update_last_seq(j);
 
 	/*
 	 * If the journal is currently full,  we might want to call flush_fn
 	 * immediately:
 	 */
-	if (seq == journal_last_seq(j))
+	if (seq == j->last_seq)
 		journal_wake(j);
 }
 
@@ -485,19 +514,19 @@ void bch2_journal_pin_set(struct journal *j, u64 seq,
 	bool wake;
 
 	scoped_guard(spinlock, &j->lock) {
-		BUG_ON(seq < journal_last_seq(j));
+		BUG_ON(seq < j->last_seq);
 
 		bool reclaim = __journal_pin_drop(j, pin);
 
 		bch2_journal_pin_set_locked(j, seq, pin, flush_fn, journal_pin_type(pin, flush_fn));
 
 		if (reclaim)
-			bch2_journal_reclaim_fast(j);
+			bch2_journal_update_last_seq(j);
 		/*
 		 * If the journal is currently full,  we might want to call flush_fn
 		 * immediately:
 		 */
-		wake = seq == journal_last_seq(j);
+		wake = seq == j->last_seq;
 	}
 
 	if (wake)
@@ -929,8 +958,8 @@ static int journal_flush_done(struct journal *j, u64 seq_to_flush,
 	 */
 	guard(spinlock)(&j->lock);
 	return !test_bit(JOURNAL_replay_done, &j->flags) ||
-		journal_last_seq(j) > seq_to_flush ||
-		!fifo_used(&j->pin);
+		j->last_seq > seq_to_flush ||
+		j->last_seq == j->pin.back;
 }
 
 bool bch2_journal_flush_pins(struct journal *j, u64 seq_to_flush)
@@ -964,39 +993,7 @@ int bch2_journal_flush_device_pins(struct journal *j, int dev_idx)
 
 	try(bch2_journal_error(j));
 
-	guard(mutex)(&c->replicas_gc_lock);
-	bch2_replicas_gc_start(c, 1 << BCH_DATA_journal);
-
-	/*
-	 * Now that we've populated replicas_gc, write to the journal to mark
-	 * active journal devices. This handles the case where the journal might
-	 * be empty. Otherwise we could clear all journal replicas and
-	 * temporarily put the fs into an unrecoverable state. Journal recovery
-	 * expects to find devices marked for journal data on unclean mount.
-	 */
-	int ret = bch2_journal_meta(&c->journal);
-	if (ret)
-		goto err;
-
-	seq = 0;
-	scoped_guard(spinlock, &j->lock)
-		while (!ret) {
-			seq = max(seq, journal_last_seq(j));
-			if (seq > j->seq_ondisk)
-				break;
-
-			union bch_replicas_padded replicas;
-			memcpy(&replicas, &journal_seq_pin(j, seq)->devs, sizeof(replicas));
-			seq++;
-
-			if (replicas.e.nr_devs) {
-				spin_unlock(&j->lock);
-				ret = bch2_mark_replicas(c, &replicas.e);
-				spin_lock(&j->lock);
-			}
-		}
-err:
-	return bch2_replicas_gc_end(c, ret);
+	return 0;
 }
 
 bool bch2_journal_seq_pins_to_text(struct printbuf *out, struct journal *j, u64 *seq)
@@ -1010,7 +1007,7 @@ bool bch2_journal_seq_pins_to_text(struct printbuf *out, struct journal *j, u64
 	if (!test_bit(JOURNAL_running, &j->flags))
 		return true;
 
-	*seq = max(*seq, j->pin.front);
+	*seq = max(*seq, j->last_seq);
 
 	if (*seq >= j->pin.back)
 		return true;
diff --git a/libbcachefs/journal/reclaim.h b/libbcachefs/journal/reclaim.h
index 2578abfa..e1956ba9 100644
--- a/libbcachefs/journal/reclaim.h
+++ b/libbcachefs/journal/reclaim.h
@@ -43,7 +43,9 @@ journal_seq_pin(struct journal *j, u64 seq)
 	return &j->pin.data[seq & j->pin.mask];
 }
 
-void bch2_journal_reclaim_fast(struct journal *);
+void bch2_journal_update_last_seq(struct journal *);
+void bch2_journal_update_last_seq_ondisk(struct journal *, u64);
+
 bool __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 *);
diff --git a/libbcachefs/journal/types.h b/libbcachefs/journal/types.h
index 43d9e842..51061443 100644
--- a/libbcachefs/journal/types.h
+++ b/libbcachefs/journal/types.h
@@ -149,6 +149,7 @@ enum journal_space_from {
 };
 
 #define JOURNAL_FLAGS()			\
+	x(degraded)			\
 	x(replay_done)			\
 	x(running)			\
 	x(may_skip_flush)		\
@@ -265,6 +266,8 @@ struct journal {
 		u64 front, back, size, mask;
 		struct journal_entry_pin_list *data;
 	}			pin;
+	u64			last_seq;
+
 	size_t			dirty_entry_bytes;
 
 	struct journal_space	space[journal_space_nr];
@@ -276,6 +279,7 @@ struct journal {
 	spinlock_t		err_lock;
 
 	struct mutex		reclaim_lock;
+	struct mutex		last_seq_ondisk_lock;
 	/*
 	 * Used for waiting until journal reclaim has freed up space in the
 	 * journal:
@@ -352,4 +356,11 @@ struct journal_entry_res {
 	unsigned		u64s;
 };
 
+struct journal_start_info {
+	u64	seq_read_start;
+	u64	seq_read_end;
+	u64	start_seq;
+	bool	clean;
+};
+
 #endif /* _BCACHEFS_JOURNAL_TYPES_H */
diff --git a/libbcachefs/journal/write.c b/libbcachefs/journal/write.c
index 477ad0a0..bf83c796 100644
--- a/libbcachefs/journal/write.c
+++ b/libbcachefs/journal/write.c
@@ -189,6 +189,7 @@ static CLOSURE_CALLBACK(journal_write_done)
 	struct journal *j = container_of(w, struct journal, buf[w->idx]);
 	struct bch_fs *c = container_of(j, struct bch_fs, journal);
 	u64 seq = le64_to_cpu(w->data->seq);
+	u64 seq_wrote = seq;
 	int err = 0;
 
 	bch2_time_stats_update(!JSET_NO_FLUSH(w->data)
@@ -197,8 +198,12 @@ static CLOSURE_CALLBACK(journal_write_done)
 
 	if (w->had_error) {
 		struct bch_replicas_entry_v1 *r = &journal_seq_pin(j, seq)->devs.e;
+		bch2_replicas_entry_put(c, r);
 
 		bch2_devlist_to_replicas(r, BCH_DATA_journal, w->devs_written);
+		err = bch2_replicas_entry_get(c, r);
+		if (err)
+			r->nr_devs = 0;
 	}
 
 	if (!w->devs_written.nr)
@@ -225,7 +230,6 @@ static CLOSURE_CALLBACK(journal_write_done)
 	BUG_ON(seq < j->pin.front);
 	if (err && (!j->err_seq || seq < j->err_seq))
 		j->err_seq	= seq;
-	w->write_done = true;
 
 	if (!j->free_buf || j->free_buf_size < w->buf_size) {
 		swap(j->free_buf,	w->data);
@@ -243,22 +247,31 @@ static CLOSURE_CALLBACK(journal_write_done)
 	}
 
 	bool completed = false;
-	bool do_discards = false;
-
+	bool last_seq_ondisk_updated = false;
+again:
 	for (seq = journal_last_unwritten_seq(j);
 	     seq <= journal_cur_seq(j);
 	     seq++) {
 		w = j->buf + (seq & JOURNAL_BUF_MASK);
-		if (!w->write_done)
+		if (!w->write_done && seq != seq_wrote)
 			break;
 
 		if (!j->err_seq && !w->noflush) {
-			j->flushed_seq_ondisk = seq;
-			j->last_seq_ondisk = w->last_seq;
+			if (j->last_seq_ondisk < w->last_seq) {
+				spin_unlock(&j->lock);
+				/*
+				 * this needs to happen _before_ updating
+				 * j->flushed_seq_ondisk, for flushing to work
+				 * properly - when the flush completes replcias
+				 * refs need to have been dropped
+				 * */
+				bch2_journal_update_last_seq_ondisk(j, w->last_seq);
+				last_seq_ondisk_updated = true;
+				spin_lock(&j->lock);
+				goto again;
+			}
 
-			closure_wake_up(&c->freelist_wait);
-			bch2_reset_alloc_cursors(c);
-			do_discards = true;
+			j->flushed_seq_ondisk = seq;
 		}
 
 		j->seq_ondisk = seq;
@@ -277,8 +290,10 @@ static CLOSURE_CALLBACK(journal_write_done)
 		completed = true;
 	}
 
+	j->buf[seq_wrote & JOURNAL_BUF_MASK].write_done = true;
+
 	if (completed) {
-		bch2_journal_reclaim_fast(j);
+		bch2_journal_update_last_seq(j);
 		bch2_journal_space_available(j);
 
 		track_event_change(&c->times[BCH_TIME_blocked_journal_max_in_flight], false);
@@ -286,6 +301,8 @@ static CLOSURE_CALLBACK(journal_write_done)
 		journal_wake(j);
 	}
 
+	j->pin.front = min(j->pin.back, j->last_seq_ondisk);
+
 	if (journal_last_unwritten_seq(j) == journal_cur_seq(j) &&
 	    j->reservations.cur_entry_offset < JOURNAL_ENTRY_CLOSED_VAL) {
 		struct journal_buf *buf = journal_cur_buf(j);
@@ -308,8 +325,11 @@ static CLOSURE_CALLBACK(journal_write_done)
 	bch2_journal_do_writes(j);
 	spin_unlock(&j->lock);
 
-	if (do_discards)
+	if (last_seq_ondisk_updated) {
+		bch2_reset_alloc_cursors(c);
+		closure_wake_up(&c->freelist_wait);
 		bch2_do_discards(c);
+	}
 
 	closure_put(&c->cl);
 }
@@ -635,7 +655,6 @@ CLOSURE_CALLBACK(bch2_journal_write)
 	unsigned nr_rw_members = dev_mask_nr(&c->rw_devs[BCH_DATA_free]);
 	int ret;
 
-	BUG_ON(BCH_SB_CLEAN(c->disk_sb.sb));
 	BUG_ON(!w->write_started);
 	BUG_ON(w->write_allocated);
 	BUG_ON(w->write_done);
@@ -702,9 +721,11 @@ CLOSURE_CALLBACK(bch2_journal_write)
 	 */
 	struct bch_replicas_entry_v1 *r = &journal_seq_pin(j, le64_to_cpu(w->data->seq))->devs.e;
 	bch2_devlist_to_replicas(r, BCH_DATA_journal, w->devs_written);
-	ret = bch2_mark_replicas(c, r);
-	if (ret)
+	ret = bch2_replicas_entry_get(c, r);
+	if (ret) {
+		r->nr_devs = 0;
 		goto err;
+	}
 
 	if (c->opts.nochanges)
 		goto no_io;
diff --git a/libbcachefs/sb/clean.c b/libbcachefs/sb/clean.c
index 18a350bc..1c36d6dd 100644
--- a/libbcachefs/sb/clean.c
+++ b/libbcachefs/sb/clean.c
@@ -256,18 +256,10 @@ const struct bch_sb_field_ops bch_sb_field_ops_clean = {
 	.to_text	= bch2_sb_clean_to_text,
 };
 
-int bch2_fs_mark_dirty(struct bch_fs *c)
+void bch2_fs_mark_dirty(struct bch_fs *c)
 {
-	/*
-	 * Unconditionally write superblock, to verify it hasn't changed before
-	 * we go rw:
-	 */
-
-	guard(mutex)(&c->sb_lock);
 	SET_BCH_SB_CLEAN(c->disk_sb.sb, false);
 	c->disk_sb.sb->features[0] |= cpu_to_le64(BCH_SB_FEATURES_ALWAYS);
-
-	return bch2_write_super(c);
 }
 
 void bch2_fs_mark_clean(struct bch_fs *c)
@@ -277,7 +269,6 @@ void bch2_fs_mark_clean(struct bch_fs *c)
 	unsigned u64s;
 	int ret;
 
-	guard(mutex)(&c->sb_lock);
 	if (BCH_SB_CLEAN(c->disk_sb.sb))
 		return;
 
@@ -321,6 +312,4 @@ void bch2_fs_mark_clean(struct bch_fs *c)
 	}
 
 	bch2_journal_pos_from_member_info_set(c);
-
-	bch2_write_super(c);
 }
diff --git a/libbcachefs/sb/clean.h b/libbcachefs/sb/clean.h
index 71caef28..6d811f12 100644
--- a/libbcachefs/sb/clean.h
+++ b/libbcachefs/sb/clean.h
@@ -10,7 +10,7 @@ void bch2_journal_super_entries_add_common(struct bch_fs *, struct jset_entry **
 
 extern const struct bch_sb_field_ops bch_sb_field_ops_clean;
 
-int bch2_fs_mark_dirty(struct bch_fs *);
+void bch2_fs_mark_dirty(struct bch_fs *);
 void bch2_fs_mark_clean(struct bch_fs *);
 
 #endif /* _BCACHEFS_SB_CLEAN_H */
diff --git a/libbcachefs/sb/io.c b/libbcachefs/sb/io.c
index 11842325..0c358c19 100644
--- a/libbcachefs/sb/io.c
+++ b/libbcachefs/sb/io.c
@@ -1021,6 +1021,11 @@ int bch2_write_super(struct bch_fs *c)
 	closure_init_stack(cl);
 	memset(&sb_written, 0, sizeof(sb_written));
 
+	if (bch2_sb_has_journal(c->disk_sb.sb))
+		bch2_fs_mark_dirty(c);
+	else
+		bch2_fs_mark_clean(c);
+
 	/*
 	 * Note: we do writes to RO devices here, and we might want to change
 	 * that in the future.
diff --git a/libbcachefs/snapshots/snapshot.c b/libbcachefs/snapshots/snapshot.c
index 7159c80c..bf6d76b3 100644
--- a/libbcachefs/snapshots/snapshot.c
+++ b/libbcachefs/snapshots/snapshot.c
@@ -1136,8 +1136,10 @@ void bch2_snapshot_delete_status_to_text(struct printbuf *out, struct bch_fs *c)
 	}
 
 	scoped_guard(mutex, &d->progress_lock) {
-		bch2_snapshot_delete_nodes_to_text(out, d);
+		prt_str(out, "Current position: ");
 		bch2_bbpos_to_text(out, d->pos);
+		prt_newline(out);
+		bch2_snapshot_delete_nodes_to_text(out, d);
 	}
 }
 
diff --git a/libbcachefs/util/printbuf.h b/libbcachefs/util/printbuf.h
index 5fa5265d..37e0b82c 100644
--- a/libbcachefs/util/printbuf.h
+++ b/libbcachefs/util/printbuf.h
@@ -71,7 +71,7 @@ enum printbuf_si {
 	PRINTBUF_UNITS_10,	/* use powers of 10^3 (standard SI) */
 };
 
-#define PRINTBUF_INLINE_TABSTOPS	6
+#define PRINTBUF_INLINE_TABSTOPS	8
 
 struct printbuf {
 	char			*buf;
diff --git a/libbcachefs/vfs/direct.c b/libbcachefs/vfs/direct.c
index c6c4a37e..cbdcf747 100644
--- a/libbcachefs/vfs/direct.c
+++ b/libbcachefs/vfs/direct.c
@@ -86,7 +86,7 @@ static int bch2_direct_IO_read(struct kiocb *req, struct iov_iter *iter)
 
 	/* bios must be 512 byte aligned: */
 	if ((offset|iter->count) & (SECTOR_SIZE - 1))
-		return -EINVAL;
+		return bch_err_throw(c, unaligned_io);
 
 	ret = min_t(loff_t, iter->count,
 		    max_t(loff_t, 0, i_size_read(&inode->v) - offset));
@@ -627,7 +627,7 @@ ssize_t bch2_direct_write(struct kiocb *req, struct iov_iter *iter)
 		goto err_put_write_ref;
 
 	if (unlikely((req->ki_pos|iter->count) & (block_bytes(c) - 1))) {
-		ret = -EINVAL;
+		ret = bch_err_throw(c, unaligned_io);
 		goto err_put_write_ref;
 	}