Update bcachefs sources to c9d875f9be1f bcachefs: Casefold is now a regular opts.h option

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

63 files changed, 1258 insertions, 764 deletions

diff --git a/.bcachefs_revision b/.bcachefs_revision
index de77df06..5fe33c98 100644
--- a/.bcachefs_revision
+++ b/.bcachefs_revision
@@ -1 +1 @@
-7307b739bbe5f1d9415f5c1da070723b3fb5abbd
+c9d875f9be1f853e747c9e00421c678b0adf73d2
diff --git a/Makefile b/Makefile
index 8cc1c9b4..3b25cf81 100644
--- a/Makefile
+++ b/Makefile
@@ -255,6 +255,7 @@ update-bcachefs-sources:
 	git rm -rf --ignore-unmatch libbcachefs
 	test -d libbcachefs || mkdir libbcachefs
 	cp $(LINUX_DIR)/fs/bcachefs/*.[ch] libbcachefs/
+	rm libbcachefs/fast_list.c libbcachefs/async_objs.c
 	git add libbcachefs/*.[ch]
 	git rm -f libbcachefs/mean_and_variance_test.c
 	cp $(LINUX_DIR)/include/linux/closure.h include/linux/
diff --git a/Makefile.compiler b/Makefile.compiler
index 8956587b..f4fcc1ea 100644
--- a/Makefile.compiler
+++ b/Makefile.compiler
@@ -79,8 +79,8 @@ ld-option = $(call try-run, $(LD) $(KBUILD_LDFLAGS) $(1) -v,$(1),$(2),$(3))
 # Usage: MY_RUSTFLAGS += $(call __rustc-option,$(RUSTC),$(MY_RUSTFLAGS),-Cinstrument-coverage,-Zinstrument-coverage)
 # TODO: remove RUSTC_BOOTSTRAP=1 when we raise the minimum GNU Make version to 4.4
 __rustc-option = $(call try-run,\
-	echo '#![allow(missing_docs)]#![feature(no_core)]#![no_core]' | RUSTC_BOOTSTRAP=1\
-	$(1) --sysroot=/dev/null $(filter-out --sysroot=/dev/null,$(2)) $(3)\
+	echo '$(pound)![allow(missing_docs)]$(pound)![feature(no_core)]$(pound)![no_core]' | RUSTC_BOOTSTRAP=1\
+	$(1) --sysroot=/dev/null $(filter-out --sysroot=/dev/null --target=%,$(2)) $(3)\
 	--crate-type=rlib --out-dir=$(TMPOUT) --emit=obj=- - >/dev/null,$(3),$(4))
 
 # rustc-option
diff --git a/c_src/cmd_device.c b/c_src/cmd_device.c
index 1fa87a18..40ac87c7 100644
--- a/c_src/cmd_device.c
+++ b/c_src/cmd_device.c
@@ -521,11 +521,11 @@ static int cmd_device_resize(int argc, char *argv[])
 
 		struct bch_dev *resize = NULL;
 
-		for_each_online_member(c, ca) {
+		for_each_online_member(c, ca, 0) {
 			if (resize)
 				die("confused: more than one online device?");
 			resize = ca;
-			percpu_ref_get(&resize->io_ref[READ]);
+			enumerated_ref_get(&resize->io_ref[READ], 0);
 		}
 
 		u64 nbuckets = size / le16_to_cpu(resize->mi.bucket_size);
@@ -538,7 +538,7 @@ static int cmd_device_resize(int argc, char *argv[])
 		if (ret)
 			fprintf(stderr, "resize error: %s\n", bch2_err_str(ret));
 
-		percpu_ref_put(&resize->io_ref[READ]);
+		enumerated_ref_put(&resize->io_ref[READ], 0);
 		bch2_fs_stop(c);
 	}
 	return 0;
@@ -618,11 +618,11 @@ static int cmd_device_resize_journal(int argc, char *argv[])
 
 		struct bch_dev *resize = NULL;
 
-		for_each_online_member(c, ca) {
+		for_each_online_member(c, ca, 0) {
 			if (resize)
 				die("confused: more than one online device?");
 			resize = ca;
-			percpu_ref_get(&resize->io_ref[READ]);
+			enumerated_ref_get(&resize->io_ref[READ], 0);
 		}
 
 		u64 nbuckets = size / le16_to_cpu(resize->mi.bucket_size);
@@ -632,7 +632,7 @@ static int cmd_device_resize_journal(int argc, char *argv[])
 		if (ret)
 			fprintf(stderr, "resize error: %s\n", bch2_err_str(ret));
 
-		percpu_ref_put(&resize->io_ref[READ]);
+		enumerated_ref_put(&resize->io_ref[READ], 0);
 		bch2_fs_stop(c);
 	}
 	return 0;
diff --git a/c_src/cmd_dump.c b/c_src/cmd_dump.c
index 04f099eb..7d7ceaa5 100644
--- a/c_src/cmd_dump.c
+++ b/c_src/cmd_dump.c
@@ -153,12 +153,12 @@ int cmd_dump(int argc, char *argv[])
 
 	down_read(&c->state_lock);
 
-	for_each_online_member(c, ca)
+	for_each_online_member(c, ca, 0)
 		nr_devices++;
 
 	BUG_ON(!nr_devices);
 
-	for_each_online_member(c, ca) {
+	for_each_online_member(c, ca, 0) {
 		int flags = O_WRONLY|O_CREAT|O_TRUNC;
 
 		if (!force)
diff --git a/include/linux/completion.h b/include/linux/completion.h
index d11a8dd0..3a5d7c6a 100644
--- a/include/linux/completion.h
+++ b/include/linux/completion.h
@@ -36,6 +36,7 @@ static inline void reinit_completion(struct completion *x)
 
 void complete(struct completion *);
 void wait_for_completion(struct completion *);
+unsigned long wait_for_completion_timeout(struct completion *, unsigned long);
 
 #define wait_for_completion_interruptible(x) (wait_for_completion(x), 0)
 
diff --git a/libbcachefs/alloc_background.c b/libbcachefs/alloc_background.c
index 8b8c2344..37cbbf86 100644
--- a/libbcachefs/alloc_background.c
+++ b/libbcachefs/alloc_background.c
@@ -17,6 +17,7 @@
 #include "debug.h"
 #include "disk_accounting.h"
 #include "ec.h"
+#include "enumerated_ref.h"
 #include "error.h"
 #include "lru.h"
 #include "recovery.h"
@@ -1381,7 +1382,7 @@ static void check_discard_freespace_key_work(struct work_struct *work)
 		container_of(work, struct check_discard_freespace_key_async, work);
 
 	bch2_trans_do(w->c, bch2_recheck_discard_freespace_key(trans, w->pos));
-	bch2_write_ref_put(w->c, BCH_WRITE_REF_check_discard_freespace_key);
+	enumerated_ref_put(&w->c->writes, BCH_WRITE_REF_check_discard_freespace_key);
 	kfree(w);
 }
 
@@ -1458,7 +1459,7 @@ delete:
 		if (!w)
 			goto out;
 
-		if (!bch2_write_ref_tryget(c, BCH_WRITE_REF_check_discard_freespace_key)) {
+		if (!enumerated_ref_tryget(&c->writes, BCH_WRITE_REF_check_discard_freespace_key)) {
 			kfree(w);
 			goto out;
 		}
@@ -1952,26 +1953,26 @@ static void bch2_do_discards_work(struct work_struct *work)
 	trace_discard_buckets(c, s.seen, s.open, s.need_journal_commit, s.discarded,
 			      bch2_err_str(ret));
 
-	percpu_ref_put(&ca->io_ref[WRITE]);
-	bch2_write_ref_put(c, BCH_WRITE_REF_discard);
+	enumerated_ref_put(&ca->io_ref[WRITE], BCH_DEV_WRITE_REF_dev_do_discards);
+	enumerated_ref_put(&c->writes, BCH_WRITE_REF_discard);
 }
 
 void bch2_dev_do_discards(struct bch_dev *ca)
 {
 	struct bch_fs *c = ca->fs;
 
-	if (!bch2_write_ref_tryget(c, BCH_WRITE_REF_discard))
+	if (!enumerated_ref_tryget(&c->writes, BCH_WRITE_REF_discard))
 		return;
 
-	if (!bch2_dev_get_ioref(c, ca->dev_idx, WRITE))
+	if (!bch2_dev_get_ioref(c, ca->dev_idx, WRITE, BCH_DEV_WRITE_REF_dev_do_discards))
 		goto put_write_ref;
 
 	if (queue_work(c->write_ref_wq, &ca->discard_work))
 		return;
 
-	percpu_ref_put(&ca->io_ref[WRITE]);
+	enumerated_ref_put(&ca->io_ref[WRITE], BCH_DEV_WRITE_REF_dev_do_discards);
 put_write_ref:
-	bch2_write_ref_put(c, BCH_WRITE_REF_discard);
+	enumerated_ref_put(&c->writes, BCH_WRITE_REF_discard);
 }
 
 void bch2_do_discards(struct bch_fs *c)
@@ -2047,8 +2048,8 @@ static void bch2_do_discards_fast_work(struct work_struct *work)
 	trace_discard_buckets_fast(c, s.seen, s.open, s.need_journal_commit, s.discarded, bch2_err_str(ret));
 
 	bch2_trans_put(trans);
-	percpu_ref_put(&ca->io_ref[WRITE]);
-	bch2_write_ref_put(c, BCH_WRITE_REF_discard_fast);
+	enumerated_ref_put(&ca->io_ref[WRITE], BCH_DEV_WRITE_REF_discard_one_bucket_fast);
+	enumerated_ref_put(&c->writes, BCH_WRITE_REF_discard_fast);
 }
 
 static void bch2_discard_one_bucket_fast(struct bch_dev *ca, u64 bucket)
@@ -2058,18 +2059,18 @@ static void bch2_discard_one_bucket_fast(struct bch_dev *ca, u64 bucket)
 	if (discard_in_flight_add(ca, bucket, false))
 		return;
 
-	if (!bch2_write_ref_tryget(c, BCH_WRITE_REF_discard_fast))
+	if (!enumerated_ref_tryget(&c->writes, BCH_WRITE_REF_discard_fast))
 		return;
 
-	if (!bch2_dev_get_ioref(c, ca->dev_idx, WRITE))
+	if (!bch2_dev_get_ioref(c, ca->dev_idx, WRITE, BCH_DEV_WRITE_REF_discard_one_bucket_fast))
 		goto put_ref;
 
 	if (queue_work(c->write_ref_wq, &ca->discard_fast_work))
 		return;
 
-	percpu_ref_put(&ca->io_ref[WRITE]);
+	enumerated_ref_put(&ca->io_ref[WRITE], BCH_DEV_WRITE_REF_discard_one_bucket_fast);
 put_ref:
-	bch2_write_ref_put(c, BCH_WRITE_REF_discard_fast);
+	enumerated_ref_put(&c->writes, BCH_WRITE_REF_discard_fast);
 }
 
 static int invalidate_one_bp(struct btree_trans *trans,
@@ -2261,27 +2262,27 @@ restart_err:
 	bch2_trans_iter_exit(trans, &iter);
 err:
 	bch2_trans_put(trans);
-	percpu_ref_put(&ca->io_ref[WRITE]);
 	bch2_bkey_buf_exit(&last_flushed, c);
-	bch2_write_ref_put(c, BCH_WRITE_REF_invalidate);
+	enumerated_ref_put(&ca->io_ref[WRITE], BCH_DEV_WRITE_REF_do_invalidates);
+	enumerated_ref_put(&c->writes, BCH_WRITE_REF_invalidate);
 }
 
 void bch2_dev_do_invalidates(struct bch_dev *ca)
 {
 	struct bch_fs *c = ca->fs;
 
-	if (!bch2_write_ref_tryget(c, BCH_WRITE_REF_invalidate))
+	if (!enumerated_ref_tryget(&c->writes, BCH_WRITE_REF_invalidate))
 		return;
 
-	if (!bch2_dev_get_ioref(c, ca->dev_idx, WRITE))
+	if (!bch2_dev_get_ioref(c, ca->dev_idx, WRITE, BCH_DEV_WRITE_REF_do_invalidates))
 		goto put_ref;
 
 	if (queue_work(c->write_ref_wq, &ca->invalidate_work))
 		return;
 
-	percpu_ref_put(&ca->io_ref[WRITE]);
+	enumerated_ref_put(&ca->io_ref[WRITE], BCH_DEV_WRITE_REF_do_invalidates);
 put_ref:
-	bch2_write_ref_put(c, BCH_WRITE_REF_invalidate);
+	enumerated_ref_put(&c->writes, BCH_WRITE_REF_invalidate);
 }
 
 void bch2_do_invalidates(struct bch_fs *c)
@@ -2503,15 +2504,15 @@ void bch2_recalc_capacity(struct bch_fs *c)
 
 	lockdep_assert_held(&c->state_lock);
 
-	for_each_online_member(c, ca) {
-		struct backing_dev_info *bdi = ca->disk_sb.bdev->bd_disk->bdi;
-
-		ra_pages += bdi->ra_pages;
-	}
+	rcu_read_lock();
+	for_each_member_device_rcu(c, ca, NULL) {
+		struct block_device *bdev = READ_ONCE(ca->disk_sb.bdev);
+		if (bdev)
+			ra_pages += bdev->bd_disk->bdi->ra_pages;
 
-	bch2_set_ra_pages(c, ra_pages);
+		if (ca->mi.state != BCH_MEMBER_STATE_rw)
+			continue;
 
-	__for_each_online_member(c, ca, BIT(BCH_MEMBER_STATE_rw), READ) {
 		u64 dev_reserve = 0;
 
 		/*
@@ -2548,6 +2549,9 @@ void bch2_recalc_capacity(struct bch_fs *c)
 		bucket_size_max = max_t(unsigned, bucket_size_max,
 					ca->mi.bucket_size);
 	}
+	rcu_read_unlock();
+
+	bch2_set_ra_pages(c, ra_pages);
 
 	gc_reserve = c->opts.gc_reserve_bytes
 		? c->opts.gc_reserve_bytes >> 9
@@ -2570,8 +2574,10 @@ u64 bch2_min_rw_member_capacity(struct bch_fs *c)
 {
 	u64 ret = U64_MAX;
 
-	for_each_rw_member(c, ca)
+	rcu_read_lock();
+	for_each_rw_member_rcu(c, ca)
 		ret = min(ret, ca->mi.nbuckets * ca->mi.bucket_size);
+	rcu_read_unlock();
 	return ret;
 }
 
@@ -2595,8 +2601,12 @@ static bool bch2_dev_has_open_write_point(struct bch_fs *c, struct bch_dev *ca)
 
 void bch2_dev_allocator_set_rw(struct bch_fs *c, struct bch_dev *ca, bool rw)
 {
+	/* BCH_DATA_free == all rw devs */
+
 	for (unsigned i = 0; i < ARRAY_SIZE(c->rw_devs); i++)
-		if (rw && (ca->mi.data_allowed & BIT(i)))
+		if (rw &&
+		    (i == BCH_DATA_free ||
+		     (ca->mi.data_allowed & BIT(i))))
 			set_bit(ca->dev_idx, c->rw_devs[i].d);
 		else
 			clear_bit(ca->dev_idx, c->rw_devs[i].d);
diff --git a/libbcachefs/alloc_foreground.c b/libbcachefs/alloc_foreground.c
index 59950d73..ac1244e7 100644
--- a/libbcachefs/alloc_foreground.c
+++ b/libbcachefs/alloc_foreground.c
@@ -1623,7 +1623,12 @@ static noinline void bch2_print_allocator_stuck(struct bch_fs *c)
 	printbuf_indent_sub(&buf, 2);
 	prt_newline(&buf);
 
-	for_each_online_member(c, ca) {
+	bch2_printbuf_make_room(&buf, 4096);
+
+	rcu_read_lock();
+	buf.atomic++;
+
+	for_each_online_member_rcu(c, ca) {
 		prt_printf(&buf, "Dev %u:\n", ca->dev_idx);
 		printbuf_indent_add(&buf, 2);
 		bch2_dev_alloc_debug_to_text(&buf, ca);
@@ -1631,6 +1636,9 @@ static noinline void bch2_print_allocator_stuck(struct bch_fs *c)
 		prt_newline(&buf);
 	}
 
+	--buf.atomic;
+	rcu_read_unlock();
+
 	prt_printf(&buf, "Copygc debug:\n");
 	printbuf_indent_add(&buf, 2);
 	bch2_copygc_wait_to_text(&buf, c);
diff --git a/libbcachefs/async_objs.h b/libbcachefs/async_objs.h
new file mode 100644
index 00000000..cd6489b8
--- /dev/null
+++ b/libbcachefs/async_objs.h
@@ -0,0 +1,44 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _BCACHEFS_ASYNC_OBJS_H
+#define _BCACHEFS_ASYNC_OBJS_H
+
+#ifdef CONFIG_BCACHEFS_ASYNC_OBJECT_LISTS
+static inline void __async_object_list_del(struct fast_list *head, unsigned idx)
+{
+	fast_list_remove(head, idx);
+}
+
+static inline int __async_object_list_add(struct fast_list *head, void *obj, unsigned *idx)
+{
+	int ret = fast_list_add(head, obj);
+	*idx = ret > 0 ? ret : 0;
+	return ret < 0 ? ret : 0;
+}
+
+#define async_object_list_del(_c, _list, idx)		\
+	__async_object_list_del(&(_c)->async_objs[BCH_ASYNC_OBJ_LIST_##_list].list, idx)
+
+#define async_object_list_add(_c, _list, obj, idx)		\
+	__async_object_list_add(&(_c)->async_objs[BCH_ASYNC_OBJ_LIST_##_list].list, obj, idx)
+
+void bch2_fs_async_obj_debugfs_init(struct bch_fs *);
+void bch2_fs_async_obj_exit(struct bch_fs *);
+int bch2_fs_async_obj_init(struct bch_fs *);
+
+#else /* CONFIG_BCACHEFS_ASYNC_OBJECT_LISTS */
+
+#define async_object_list_del(_c, _n, idx)		do {} while (0)
+
+static inline int __async_object_list_add(void)
+{
+	return 0;
+}
+#define async_object_list_add(_c, _n, obj, idx)		__async_object_list_add()
+
+static inline void bch2_fs_async_obj_debugfs_init(struct bch_fs *c) {}
+static inline void bch2_fs_async_obj_exit(struct bch_fs *c) {}
+static inline int bch2_fs_async_obj_init(struct bch_fs *c) { return 0; }
+
+#endif /* CONFIG_BCACHEFS_ASYNC_OBJECT_LISTS */
+
+#endif /* _BCACHEFS_ASYNC_OBJS_H */
diff --git a/libbcachefs/async_objs_types.h b/libbcachefs/async_objs_types.h
new file mode 100644
index 00000000..310a4f90
--- /dev/null
+++ b/libbcachefs/async_objs_types.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _BCACHEFS_ASYNC_OBJS_TYPES_H
+#define _BCACHEFS_ASYNC_OBJS_TYPES_H
+
+#define BCH_ASYNC_OBJ_LISTS()						\
+	x(promote)							\
+	x(rbio)								\
+	x(btree_read_bio)						\
+	x(btree_write_bio)
+
+enum bch_async_obj_lists {
+#define x(n)		BCH_ASYNC_OBJ_LIST_##n,
+	BCH_ASYNC_OBJ_LISTS()
+#undef x
+	BCH_ASYNC_OBJ_NR
+};
+
+struct async_obj_list {
+	struct fast_list	list;
+	void			(*obj_to_text)(struct printbuf *, void *);
+	unsigned		idx;
+};
+
+#endif /* _BCACHEFS_ASYNC_OBJS_TYPES_H */
diff --git a/libbcachefs/backpointers.c b/libbcachefs/backpointers.c
index ff26bb51..b870eedf 100644
--- a/libbcachefs/backpointers.c
+++ b/libbcachefs/backpointers.c
@@ -437,7 +437,8 @@ found:
 
 	bytes = p.crc.compressed_size << 9;
 
-	struct bch_dev *ca = bch2_dev_get_ioref(c, dev, READ);
+	struct bch_dev *ca = bch2_dev_get_ioref(c, dev, READ,
+				BCH_DEV_READ_REF_check_extent_checksums);
 	if (!ca)
 		return false;
 
@@ -474,7 +475,8 @@ err:
 	if (bio)
 		bio_put(bio);
 	kvfree(data_buf);
-	percpu_ref_put(&ca->io_ref[READ]);
+	enumerated_ref_put(&ca->io_ref[READ],
+			   BCH_DEV_READ_REF_check_extent_checksums);
 	printbuf_exit(&buf);
 	return ret;
 }
diff --git a/libbcachefs/bcachefs.h b/libbcachefs/bcachefs.h
index a1a4e941..675b8f8e 100644
--- a/libbcachefs/bcachefs.h
+++ b/libbcachefs/bcachefs.h
@@ -209,6 +209,7 @@
 #include "btree_journal_iter_types.h"
 #include "disk_accounting_types.h"
 #include "errcode.h"
+#include "fast_list.h"
 #include "fifo.h"
 #include "nocow_locking_types.h"
 #include "opts.h"
@@ -219,7 +220,7 @@
 #include "util.h"
 
 #ifdef CONFIG_BCACHEFS_DEBUG
-#define BCH_WRITE_REF_DEBUG
+#define ENUMERATED_REF_DEBUG
 #endif
 
 #ifndef dynamic_fault
@@ -474,6 +475,7 @@ enum bch_time_stats {
 };
 
 #include "alloc_types.h"
+#include "async_objs_types.h"
 #include "btree_gc_types.h"
 #include "btree_types.h"
 #include "btree_node_scan_types.h"
@@ -483,6 +485,7 @@ enum bch_time_stats {
 #include "clock_types.h"
 #include "disk_groups_types.h"
 #include "ec_types.h"
+#include "enumerated_ref_types.h"
 #include "journal_types.h"
 #include "keylist_types.h"
 #include "quota_types.h"
@@ -515,6 +518,51 @@ struct discard_in_flight {
 	u64			bucket:63;
 };
 
+#define BCH_DEV_READ_REFS()				\
+	x(bch2_online_devs)				\
+	x(trans_mark_dev_sbs)				\
+	x(read_fua_test)				\
+	x(sb_field_resize)				\
+	x(write_super)					\
+	x(journal_read)					\
+	x(fs_journal_alloc)				\
+	x(fs_resize_on_mount)				\
+	x(btree_node_read)				\
+	x(btree_node_read_all_replicas)			\
+	x(btree_node_scrub)				\
+	x(btree_node_write)				\
+	x(btree_node_scan)				\
+	x(btree_verify_replicas)			\
+	x(btree_node_ondisk_to_text)			\
+	x(io_read)					\
+	x(check_extent_checksums)			\
+	x(ec_block)
+
+enum bch_dev_read_ref {
+#define x(n) BCH_DEV_READ_REF_##n,
+	BCH_DEV_READ_REFS()
+#undef x
+	BCH_DEV_READ_REF_NR,
+};
+
+#define BCH_DEV_WRITE_REFS()				\
+	x(journal_write)				\
+	x(journal_do_discards)				\
+	x(dev_do_discards)				\
+	x(discard_one_bucket_fast)			\
+	x(do_invalidates)				\
+	x(nocow_flush)					\
+	x(io_write)					\
+	x(ec_block)					\
+	x(ec_bucket_zero)
+
+enum bch_dev_write_ref {
+#define x(n) BCH_DEV_WRITE_REF_##n,
+	BCH_DEV_WRITE_REFS()
+#undef x
+	BCH_DEV_WRITE_REF_NR,
+};
+
 struct bch_dev {
 	struct kobject		kobj;
 #ifdef CONFIG_BCACHEFS_DEBUG
@@ -525,8 +573,7 @@ struct bch_dev {
 	struct percpu_ref	ref;
 #endif
 	struct completion	ref_completion;
-	struct percpu_ref	io_ref[2];
-	struct completion	io_ref_completion[2];
+	struct enumerated_ref	io_ref[2];
 
 	struct bch_fs		*fs;
 
@@ -733,11 +780,7 @@ struct bch_fs {
 	struct rw_semaphore	state_lock;
 
 	/* Counts outstanding writes, for clean transition to read-only */
-#ifdef BCH_WRITE_REF_DEBUG
-	atomic_long_t		writes[BCH_WRITE_REF_NR];
-#else
-	struct percpu_ref	writes;
-#endif
+	struct enumerated_ref	writes;
 	/*
 	 * Certain operations are only allowed in single threaded mode, during
 	 * recovery, and we want to assert that this is the case:
@@ -891,6 +934,7 @@ struct bch_fs {
 	struct workqueue_struct *write_ref_wq;
 
 	/* ALLOCATION */
+	struct bch_devs_mask	online_devs;
 	struct bch_devs_mask	rw_devs[BCH_DATA_NR];
 	unsigned long		rw_devs_change_count;
 
@@ -985,6 +1029,10 @@ struct bch_fs {
 				nocow_locks;
 	struct rhashtable	promote_table;
 
+#ifdef CONFIG_BCACHEFS_ASYNC_OBJECT_LISTS
+	struct async_obj_list	async_objs[BCH_ASYNC_OBJ_NR];
+#endif
+
 	mempool_t		compression_bounce[2];
 	mempool_t		compress_workspace[BCH_COMPRESSION_OPT_NR];
 	size_t			zstd_workspace_size;
@@ -1073,6 +1121,7 @@ struct bch_fs {
 	/* DEBUG JUNK */
 	struct dentry		*fs_debug_dir;
 	struct dentry		*btree_debug_dir;
+	struct dentry		*async_obj_dir;
 	struct btree_debug	btree_debug[BTREE_ID_NR];
 	struct btree		*verify_data;
 	struct btree_node	*verify_ondisk;
@@ -1114,54 +1163,6 @@ struct bch_fs {
 
 extern struct wait_queue_head bch2_read_only_wait;
 
-static inline void bch2_write_ref_get(struct bch_fs *c, enum bch_write_ref ref)
-{
-#ifdef BCH_WRITE_REF_DEBUG
-	atomic_long_inc(&c->writes[ref]);
-#else
-	percpu_ref_get(&c->writes);
-#endif
-}
-
-static inline bool __bch2_write_ref_tryget(struct bch_fs *c, enum bch_write_ref ref)
-{
-#ifdef BCH_WRITE_REF_DEBUG
-	return !test_bit(BCH_FS_going_ro, &c->flags) &&
-		atomic_long_inc_not_zero(&c->writes[ref]);
-#else
-	return percpu_ref_tryget(&c->writes);
-#endif
-}
-
-static inline bool bch2_write_ref_tryget(struct bch_fs *c, enum bch_write_ref ref)
-{
-#ifdef BCH_WRITE_REF_DEBUG
-	return !test_bit(BCH_FS_going_ro, &c->flags) &&
-		atomic_long_inc_not_zero(&c->writes[ref]);
-#else
-	return percpu_ref_tryget_live(&c->writes);
-#endif
-}
-
-static inline void bch2_write_ref_put(struct bch_fs *c, enum bch_write_ref ref)
-{
-#ifdef BCH_WRITE_REF_DEBUG
-	long v = atomic_long_dec_return(&c->writes[ref]);
-
-	BUG_ON(v < 0);
-	if (v)
-		return;
-	for (unsigned i = 0; i < BCH_WRITE_REF_NR; i++)
-		if (atomic_long_read(&c->writes[i]))
-			return;
-
-	set_bit(BCH_FS_write_disable_complete, &c->flags);
-	wake_up(&bch2_read_only_wait);
-#else
-	percpu_ref_put(&c->writes);
-#endif
-}
-
 static inline bool bch2_ro_ref_tryget(struct bch_fs *c)
 {
 	if (test_bit(BCH_FS_stopping, &c->flags))
diff --git a/libbcachefs/bcachefs_format.h b/libbcachefs/bcachefs_format.h
index 9af2a607..7ce475c5 100644
--- a/libbcachefs/bcachefs_format.h
+++ b/libbcachefs/bcachefs_format.h
@@ -868,6 +868,7 @@ LE64_BITMASK(BCH_SB_SHARD_INUMS_NBITS,	struct bch_sb, flags[6],  0,  4);
 LE64_BITMASK(BCH_SB_WRITE_ERROR_TIMEOUT,struct bch_sb, flags[6],  4, 14);
 LE64_BITMASK(BCH_SB_CSUM_ERR_RETRY_NR,	struct bch_sb, flags[6], 14, 20);
 LE64_BITMASK(BCH_SB_DEGRADED_ACTION,	struct bch_sb, flags[6], 20, 22);
+LE64_BITMASK(BCH_SB_CASEFOLD,		struct bch_sb, flags[6], 22, 23);
 
 static inline __u64 BCH_SB_COMPRESSION_TYPE(const struct bch_sb *sb)
 {
diff --git a/libbcachefs/btree_gc.c b/libbcachefs/btree_gc.c
index 2824a6e8..9db8f5f8 100644
--- a/libbcachefs/btree_gc.c
+++ b/libbcachefs/btree_gc.c
@@ -22,6 +22,7 @@
 #include "debug.h"
 #include "disk_accounting.h"
 #include "ec.h"
+#include "enumerated_ref.h"
 #include "error.h"
 #include "extents.h"
 #include "journal.h"
@@ -1233,14 +1234,14 @@ static void bch2_gc_gens_work(struct work_struct *work)
 {
 	struct bch_fs *c = container_of(work, struct bch_fs, gc_gens_work);
 	bch2_gc_gens(c);
-	bch2_write_ref_put(c, BCH_WRITE_REF_gc_gens);
+	enumerated_ref_put(&c->writes, BCH_WRITE_REF_gc_gens);
 }
 
 void bch2_gc_gens_async(struct bch_fs *c)
 {
-	if (bch2_write_ref_tryget(c, BCH_WRITE_REF_gc_gens) &&
+	if (enumerated_ref_tryget(&c->writes, BCH_WRITE_REF_gc_gens) &&
 	    !queue_work(c->write_ref_wq, &c->gc_gens_work))
-		bch2_write_ref_put(c, BCH_WRITE_REF_gc_gens);
+		enumerated_ref_put(&c->writes, BCH_WRITE_REF_gc_gens);
 }
 
 void bch2_fs_btree_gc_init_early(struct bch_fs *c)
diff --git a/libbcachefs/btree_io.c b/libbcachefs/btree_io.c
index a261e856..5cd27a9c 100644
--- a/libbcachefs/btree_io.c
+++ b/libbcachefs/btree_io.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 
 #include "bcachefs.h"
+#include "async_objs.h"
 #include "bkey_buf.h"
 #include "bkey_methods.h"
 #include "bkey_sort.h"
@@ -13,6 +14,7 @@
 #include "buckets.h"
 #include "checksum.h"
 #include "debug.h"
+#include "enumerated_ref.h"
 #include "error.h"
 #include "extents.h"
 #include "io_write.h"
@@ -1324,7 +1326,7 @@ static void btree_node_read_work(struct work_struct *work)
 	while (1) {
 		retry = true;
 		bch_info(c, "retrying read");
-		ca = bch2_dev_get_ioref(c, rb->pick.ptr.dev, READ);
+		ca = bch2_dev_get_ioref(c, rb->pick.ptr.dev, READ, BCH_DEV_READ_REF_btree_node_read);
 		rb->have_ioref		= ca != NULL;
 		rb->start_time		= local_clock();
 		bio_reset(bio, NULL, REQ_OP_READ|REQ_SYNC|REQ_META);
@@ -1349,7 +1351,7 @@ start:
 					"btree read error %s for %s",
 					bch2_blk_status_to_str(bio->bi_status), buf.buf);
 		if (rb->have_ioref)
-			percpu_ref_put(&ca->io_ref[READ]);
+			enumerated_ref_put(&ca->io_ref[READ], BCH_DEV_READ_REF_btree_node_read);
 		rb->have_ioref = false;
 
 		bch2_mark_io_failure(&failed, &rb->pick, false);
@@ -1374,6 +1376,7 @@ start:
 		}
 	}
 
+	async_object_list_del(c, btree_read_bio, rb->list_idx);
 	bch2_time_stats_update(&c->times[BCH_TIME_btree_node_read],
 			       rb->start_time);
 	bio_put(&rb->bio);
@@ -1413,6 +1416,11 @@ static void btree_node_read_endio(struct bio *bio)
 	queue_work(c->btree_read_complete_wq, &rb->work);
 }
 
+void bch2_btree_read_bio_to_text(struct printbuf *out, struct btree_read_bio *rbio)
+{
+	bch2_bio_to_text(out, &rbio->bio);
+}
+
 struct btree_node_read_all {
 	struct closure		cl;
 	struct bch_fs		*c;
@@ -1605,7 +1613,8 @@ static void btree_node_read_all_replicas_endio(struct bio *bio)
 		struct bch_dev *ca = bch2_dev_have_ref(c, rb->pick.ptr.dev);
 
 		bch2_latency_acct(ca, rb->start_time, READ);
-		percpu_ref_put(&ca->io_ref[READ]);
+		enumerated_ref_put(&ca->io_ref[READ],
+			BCH_DEV_READ_REF_btree_node_read_all_replicas);
 	}
 
 	ra->err[rb->idx] = bio->bi_status;
@@ -1645,7 +1654,8 @@ static int btree_node_read_all_replicas(struct bch_fs *c, struct btree *b, bool
 
 	i = 0;
 	bkey_for_each_ptr_decode(k.k, ptrs, pick, entry) {
-		struct bch_dev *ca = bch2_dev_get_ioref(c, pick.ptr.dev, READ);
+		struct bch_dev *ca = bch2_dev_get_ioref(c, pick.ptr.dev, READ,
+					BCH_DEV_READ_REF_btree_node_read_all_replicas);
 		struct btree_read_bio *rb =
 			container_of(ra->bio[i], struct btree_read_bio, bio);
 		rb->c			= c;
@@ -1722,7 +1732,7 @@ void bch2_btree_node_read(struct btree_trans *trans, struct btree *b,
 		return;
 	}
 
-	ca = bch2_dev_get_ioref(c, pick.ptr.dev, READ);
+	ca = bch2_dev_get_ioref(c, pick.ptr.dev, READ, BCH_DEV_READ_REF_btree_node_read);
 
 	bio = bio_alloc_bioset(NULL,
 			       buf_pages(b->data, btree_buf_bytes(b)),
@@ -1741,6 +1751,8 @@ void bch2_btree_node_read(struct btree_trans *trans, struct btree *b,
 	bio->bi_end_io		= btree_node_read_endio;
 	bch2_bio_map(bio, b->data, btree_buf_bytes(b));
 
+	async_object_list_add(c, btree_read_bio, rb, &rb->list_idx);
+
 	if (rb->have_ioref) {
 		this_cpu_add(ca->io_done->sectors[READ][BCH_DATA_btree],
 			     bio_sectors(bio));
@@ -1925,9 +1937,9 @@ err:
 	printbuf_exit(&err);
 	bch2_bkey_buf_exit(&scrub->key, c);;
 	btree_bounce_free(c, c->opts.btree_node_size, scrub->used_mempool, scrub->buf);
-	percpu_ref_put(&scrub->ca->io_ref[READ]);
+	enumerated_ref_put(&scrub->ca->io_ref[READ], BCH_DEV_READ_REF_btree_node_scrub);
 	kfree(scrub);
-	bch2_write_ref_put(c, BCH_WRITE_REF_btree_node_scrub);
+	enumerated_ref_put(&c->writes, BCH_WRITE_REF_btree_node_scrub);
 }
 
 static void btree_node_scrub_endio(struct bio *bio)
@@ -1946,7 +1958,7 @@ int bch2_btree_node_scrub(struct btree_trans *trans,
 
 	struct bch_fs *c = trans->c;
 
-	if (!bch2_write_ref_tryget(c, BCH_WRITE_REF_btree_node_scrub))
+	if (!enumerated_ref_tryget(&c->writes, BCH_WRITE_REF_btree_node_scrub))
 		return -BCH_ERR_erofs_no_writes;
 
 	struct extent_ptr_decoded pick;
@@ -1954,7 +1966,8 @@ int bch2_btree_node_scrub(struct btree_trans *trans,
 	if (ret <= 0)
 		goto err;
 
-	struct bch_dev *ca = bch2_dev_get_ioref(c, pick.ptr.dev, READ);
+	struct bch_dev *ca = bch2_dev_get_ioref(c, pick.ptr.dev, READ,
+						BCH_DEV_READ_REF_btree_node_scrub);
 	if (!ca) {
 		ret = -BCH_ERR_device_offline;
 		goto err;
@@ -1994,9 +2007,9 @@ int bch2_btree_node_scrub(struct btree_trans *trans,
 	return 0;
 err_free:
 	btree_bounce_free(c, c->opts.btree_node_size, used_mempool, buf);
-	percpu_ref_put(&ca->io_ref[READ]);
+	enumerated_ref_put(&ca->io_ref[READ], BCH_DEV_READ_REF_btree_node_scrub);
 err:
-	bch2_write_ref_put(c, BCH_WRITE_REF_btree_node_scrub);
+	enumerated_ref_put(&c->writes, BCH_WRITE_REF_btree_node_scrub);
 	return ret;
 }
 
@@ -2111,6 +2124,7 @@ static void btree_node_write_work(struct work_struct *work)
 			goto err;
 	}
 out:
+	async_object_list_del(c, btree_write_bio, wbio->list_idx);
 	bio_put(&wbio->wbio.bio);
 	btree_node_write_done(c, b, start_time);
 	return;
@@ -2162,7 +2176,8 @@ static void btree_node_write_endio(struct bio *bio)
 	 * btree writes yet (due to device removal/ro):
 	 */
 	if (wbio->have_ioref)
-		percpu_ref_put(&ca->io_ref[READ]);
+		enumerated_ref_put(&ca->io_ref[READ],
+				   BCH_DEV_READ_REF_btree_node_write);
 
 	if (parent) {
 		bio_put(bio);
@@ -2461,6 +2476,8 @@ do_write:
 	atomic64_inc(&c->btree_write_stats[type].nr);
 	atomic64_add(bytes_to_write, &c->btree_write_stats[type].bytes);
 
+	async_object_list_add(c, btree_write_bio, wbio, &wbio->list_idx);
+
 	INIT_WORK(&wbio->work, btree_write_submit);
 	queue_work(c->btree_write_submit_wq, &wbio->work);
 	return;
diff --git a/libbcachefs/btree_io.h b/libbcachefs/btree_io.h
index dbf76d22..afdb11a9 100644
--- a/libbcachefs/btree_io.h
+++ b/libbcachefs/btree_io.h
@@ -41,6 +41,9 @@ struct btree_read_bio {
 	u64			start_time;
 	unsigned		have_ioref:1;
 	unsigned		idx:7;
+#ifdef CONFIG_BCACHEFS_ASYNC_OBJECT_LISTS
+	unsigned		list_idx;
+#endif
 	struct extent_ptr_decoded	pick;
 	struct work_struct	work;
 	struct bio		bio;
@@ -53,6 +56,9 @@ struct btree_write_bio {
 	unsigned		data_bytes;
 	unsigned		sector_offset;
 	u64			start_time;
+#ifdef CONFIG_BCACHEFS_ASYNC_OBJECT_LISTS
+	unsigned		list_idx;
+#endif
 	struct bch_write_bio	wbio;
 };
 
@@ -133,6 +139,8 @@ void bch2_btree_node_read(struct btree_trans *, struct btree *, bool);
 int bch2_btree_root_read(struct bch_fs *, enum btree_id,
 			 const struct bkey_i *, unsigned);
 
+void bch2_btree_read_bio_to_text(struct printbuf *, struct btree_read_bio *);
+
 int bch2_btree_node_scrub(struct btree_trans *, enum btree_id, unsigned,
 			  struct bkey_s_c, unsigned);
 
diff --git a/libbcachefs/btree_node_scan.c b/libbcachefs/btree_node_scan.c
index 81ee7ae8..7bd13438 100644
--- a/libbcachefs/btree_node_scan.c
+++ b/libbcachefs/btree_node_scan.c
@@ -271,7 +271,7 @@ static int read_btree_nodes_worker(void *p)
 err:
 	bio_put(bio);
 	free_page((unsigned long) buf);
-	percpu_ref_put(&ca->io_ref[READ]);
+	enumerated_ref_put(&ca->io_ref[READ], BCH_DEV_READ_REF_btree_node_scan);
 	closure_put(w->cl);
 	kfree(w);
 	return 0;
@@ -285,13 +285,13 @@ static int read_btree_nodes(struct find_btree_nodes *f)
 
 	closure_init_stack(&cl);
 
-	for_each_online_member(c, ca) {
+	for_each_online_member(c, ca, BCH_DEV_READ_REF_btree_node_scan) {
 		if (!(ca->mi.data_allowed & BIT(BCH_DATA_btree)))
 			continue;
 
 		struct find_btree_nodes_worker *w = kmalloc(sizeof(*w), GFP_KERNEL);
 		if (!w) {
-			percpu_ref_put(&ca->io_ref[READ]);
+			enumerated_ref_put(&ca->io_ref[READ], BCH_DEV_READ_REF_btree_node_scan);
 			ret = -ENOMEM;
 			goto err;
 		}
@@ -303,14 +303,14 @@ static int read_btree_nodes(struct find_btree_nodes *f)
 		struct task_struct *t = kthread_create(read_btree_nodes_worker, w, "read_btree_nodes/%s", ca->name);
 		ret = PTR_ERR_OR_ZERO(t);
 		if (ret) {
-			percpu_ref_put(&ca->io_ref[READ]);
+			enumerated_ref_put(&ca->io_ref[READ], BCH_DEV_READ_REF_btree_node_scan);
 			kfree(w);
 			bch_err_msg(c, ret, "starting kthread");
 			break;
 		}
 
 		closure_get(&cl);
-		percpu_ref_get(&ca->io_ref[READ]);
+		enumerated_ref_get(&ca->io_ref[READ], BCH_DEV_READ_REF_btree_node_scan);
 		wake_up_process(t);
 	}
 err:
diff --git a/libbcachefs/btree_trans_commit.c b/libbcachefs/btree_trans_commit.c
index 4297d8b5..cdde769e 100644
--- a/libbcachefs/btree_trans_commit.c
+++ b/libbcachefs/btree_trans_commit.c
@@ -11,6 +11,7 @@
 #include "btree_write_buffer.h"
 #include "buckets.h"
 #include "disk_accounting.h"
+#include "enumerated_ref.h"
 #include "errcode.h"
 #include "error.h"
 #include "journal.h"
@@ -994,7 +995,7 @@ int __bch2_trans_commit(struct btree_trans *trans, unsigned flags)
 		goto out_reset;
 
 	if (!(flags & BCH_TRANS_COMMIT_no_check_rw) &&
-	    unlikely(!bch2_write_ref_tryget(c, BCH_WRITE_REF_trans))) {
+	    unlikely(!enumerated_ref_tryget(&c->writes, BCH_WRITE_REF_trans))) {
 		if (unlikely(!test_bit(BCH_FS_may_go_rw, &c->flags)))
 			ret = do_bch2_trans_commit_to_journal_replay(trans);
 		else
@@ -1060,7 +1061,7 @@ retry:
 	trace_and_count(c, transaction_commit, trans, _RET_IP_);
 out:
 	if (likely(!(flags & BCH_TRANS_COMMIT_no_check_rw)))
-		bch2_write_ref_put(c, BCH_WRITE_REF_trans);
+		enumerated_ref_put(&c->writes, BCH_WRITE_REF_trans);
 out_reset:
 	if (!ret)
 		bch2_trans_downgrade(trans);
diff --git a/libbcachefs/btree_update_interior.c b/libbcachefs/btree_update_interior.c
index a0ff2dc0..fcca8b01 100644
--- a/libbcachefs/btree_update_interior.c
+++ b/libbcachefs/btree_update_interior.c
@@ -14,6 +14,7 @@
 #include "btree_locking.h"
 #include "buckets.h"
 #include "clock.h"
+#include "enumerated_ref.h"
 #include "error.h"
 #include "extents.h"
 #include "io_write.h"
@@ -2326,7 +2327,7 @@ static void async_btree_node_rewrite_work(struct work_struct *work)
 	closure_wake_up(&c->btree_node_rewrites_wait);
 
 	bch2_bkey_buf_exit(&a->key, c);
-	bch2_write_ref_put(c, BCH_WRITE_REF_node_rewrite);
+	enumerated_ref_put(&c->writes, BCH_WRITE_REF_node_rewrite);
 	kfree(a);
 }
 
@@ -2348,7 +2349,7 @@ void bch2_btree_node_rewrite_async(struct bch_fs *c, struct btree *b)
 
 	spin_lock(&c->btree_node_rewrites_lock);
 	if (c->curr_recovery_pass > BCH_RECOVERY_PASS_journal_replay &&
-	    bch2_write_ref_tryget(c, BCH_WRITE_REF_node_rewrite)) {
+	    enumerated_ref_tryget(&c->writes, BCH_WRITE_REF_node_rewrite)) {
 		list_add(&a->list, &c->btree_node_rewrites);
 		now = true;
 	} else if (!test_bit(BCH_FS_may_go_rw, &c->flags)) {
@@ -2387,7 +2388,7 @@ void bch2_do_pending_node_rewrites(struct bch_fs *c)
 		if (!a)
 			break;
 
-		bch2_write_ref_get(c, BCH_WRITE_REF_node_rewrite);
+		enumerated_ref_get(&c->writes, BCH_WRITE_REF_node_rewrite);
 		queue_work(c->btree_node_rewrite_worker, &a->work);
 	}
 }
diff --git a/libbcachefs/btree_write_buffer.c b/libbcachefs/btree_write_buffer.c
index 68ab48af..0094e434 100644
--- a/libbcachefs/btree_write_buffer.c
+++ b/libbcachefs/btree_write_buffer.c
@@ -7,6 +7,7 @@
 #include "btree_update_interior.h"
 #include "btree_write_buffer.h"
 #include "disk_accounting.h"
+#include "enumerated_ref.h"
 #include "error.h"
 #include "extents.h"
 #include "journal.h"
@@ -629,11 +630,11 @@ int bch2_btree_write_buffer_tryflush(struct btree_trans *trans)
 {
 	struct bch_fs *c = trans->c;
 
-	if (!bch2_write_ref_tryget(c, BCH_WRITE_REF_btree_write_buffer))
+	if (!enumerated_ref_tryget(&c->writes, BCH_WRITE_REF_btree_write_buffer))
 		return -BCH_ERR_erofs_no_writes;
 
 	int ret = bch2_btree_write_buffer_flush_nocheck_rw(trans);
-	bch2_write_ref_put(c, BCH_WRITE_REF_btree_write_buffer);
+	enumerated_ref_put(&c->writes, BCH_WRITE_REF_btree_write_buffer);
 	return ret;
 }
 
@@ -692,7 +693,7 @@ static void bch2_btree_write_buffer_flush_work(struct work_struct *work)
 	} while (!ret && bch2_btree_write_buffer_should_flush(c));
 	mutex_unlock(&wb->flushing.lock);
 
-	bch2_write_ref_put(c, BCH_WRITE_REF_btree_write_buffer);
+	enumerated_ref_put(&c->writes, BCH_WRITE_REF_btree_write_buffer);
 }
 
 static void wb_accounting_sort(struct btree_write_buffer *wb)
@@ -821,9 +822,9 @@ int bch2_journal_keys_to_write_buffer_end(struct bch_fs *c, struct journal_keys_
 		bch2_journal_pin_drop(&c->journal, &dst->wb->pin);
 
 	if (bch2_btree_write_buffer_should_flush(c) &&
-	    __bch2_write_ref_tryget(c, BCH_WRITE_REF_btree_write_buffer) &&
+	    __enumerated_ref_tryget(&c->writes, BCH_WRITE_REF_btree_write_buffer) &&
 	    !queue_work(system_unbound_wq, &c->btree_write_buffer.flush_work))
-		bch2_write_ref_put(c, BCH_WRITE_REF_btree_write_buffer);
+		enumerated_ref_put(&c->writes, BCH_WRITE_REF_btree_write_buffer);
 
 	if (dst->wb == &wb->flushing)
 		mutex_unlock(&wb->flushing.lock);
diff --git a/libbcachefs/buckets.c b/libbcachefs/buckets.c
index 09e84d4a..7c267244 100644
--- a/libbcachefs/buckets.c
+++ b/libbcachefs/buckets.c
@@ -1139,10 +1139,10 @@ int bch2_trans_mark_dev_sb(struct bch_fs *c, struct bch_dev *ca,
 int bch2_trans_mark_dev_sbs_flags(struct bch_fs *c,
 			enum btree_iter_update_trigger_flags flags)
 {
-	for_each_online_member(c, ca) {
+	for_each_online_member(c, ca, BCH_DEV_READ_REF_trans_mark_dev_sbs) {
 		int ret = bch2_trans_mark_dev_sb(c, ca, flags);
 		if (ret) {
-			percpu_ref_put(&ca->io_ref[READ]);
+			enumerated_ref_put(&ca->io_ref[READ], BCH_DEV_READ_REF_trans_mark_dev_sbs);
 			return ret;
 		}
 	}
diff --git a/libbcachefs/chardev.c b/libbcachefs/chardev.c
index 5891b3a1..4066946b 100644
--- a/libbcachefs/chardev.c
+++ b/libbcachefs/chardev.c
@@ -613,11 +613,13 @@ static long bch2_ioctl_disk_get_idx(struct bch_fs *c,
 	if (!dev)
 		return -EINVAL;
 
-	for_each_online_member(c, ca)
+	rcu_read_lock();
+	for_each_online_member_rcu(c, ca)
 		if (ca->dev == dev) {
-			percpu_ref_put(&ca->io_ref[READ]);
+			rcu_read_unlock();
 			return ca->dev_idx;
 		}
+	rcu_read_unlock();
 
 	return -BCH_ERR_ENOENT_dev_idx_not_found;
 }
diff --git a/libbcachefs/data_update.c b/libbcachefs/data_update.c
index c3034338..9b44f11f 100644
--- a/libbcachefs/data_update.c
+++ b/libbcachefs/data_update.c
@@ -587,6 +587,10 @@ void bch2_data_update_opts_to_text(struct printbuf *out, struct bch_fs *c,
 
 	prt_str_indented(out, "extra replicas:\t");
 	prt_u64(out, data_opts->extra_replicas);
+	prt_newline(out);
+
+	prt_str_indented(out, "scrub:\t");
+	prt_u64(out, data_opts->scrub);
 }
 
 void bch2_data_update_to_text(struct printbuf *out, struct data_update *m)
@@ -607,9 +611,17 @@ void bch2_data_update_inflight_to_text(struct printbuf *out, struct data_update
 	prt_newline(out);
 	printbuf_indent_add(out, 2);
 	bch2_data_update_opts_to_text(out, m->op.c, &m->op.opts, &m->data_opts);
-	prt_printf(out, "read_done:\t%u\n", m->read_done);
-	bch2_write_op_to_text(out, &m->op);
-	printbuf_indent_sub(out, 2);
+
+	if (!m->read_done) {
+		prt_printf(out, "read:\n");
+		printbuf_indent_add(out, 2);
+		bch2_read_bio_to_text(out, &m->rbio);
+	} else {
+		prt_printf(out, "write:\n");
+		printbuf_indent_add(out, 2);
+		bch2_write_op_to_text(out, &m->op);
+	}
+	printbuf_indent_sub(out, 4);
 }
 
 int bch2_extent_drop_ptrs(struct btree_trans *trans,
diff --git a/libbcachefs/data_update.h b/libbcachefs/data_update.h
index ed051258..5e14d135 100644
--- a/libbcachefs/data_update.h
+++ b/libbcachefs/data_update.h
@@ -50,6 +50,21 @@ struct data_update {
 	struct bio_vec		*bvecs;
 };
 
+struct promote_op {
+	struct rcu_head		rcu;
+	u64			start_time;
+#ifdef CONFIG_BCACHEFS_ASYNC_OBJECT_LISTS
+	unsigned		list_idx;
+#endif
+
+	struct rhash_head	hash;
+	struct bpos		pos;
+
+	struct work_struct	work;
+	struct data_update	write;
+	struct bio_vec		bi_inline_vecs[]; /* must be last */
+};
+
 void bch2_data_update_to_text(struct printbuf *, struct data_update *);
 void bch2_data_update_inflight_to_text(struct printbuf *, struct data_update *);
 
diff --git a/libbcachefs/debug.c b/libbcachefs/debug.c
index 8ad710bb..c24de2e3 100644
--- a/libbcachefs/debug.c
+++ b/libbcachefs/debug.c
@@ -8,6 +8,7 @@
 
 #include "bcachefs.h"
 #include "alloc_foreground.h"
+#include "async_objs.h"
 #include "bkey_methods.h"
 #include "btree_cache.h"
 #include "btree_io.h"
@@ -16,6 +17,7 @@
 #include "btree_update.h"
 #include "btree_update_interior.h"
 #include "buckets.h"
+#include "data_update.h"
 #include "debug.h"
 #include "error.h"
 #include "extents.h"
@@ -42,7 +44,8 @@ static bool bch2_btree_verify_replica(struct bch_fs *c, struct btree *b,
 	struct bio *bio;
 	bool failed = false, saw_error = false;
 
-	struct bch_dev *ca = bch2_dev_get_ioref(c, pick.ptr.dev, READ);
+	struct bch_dev *ca = bch2_dev_get_ioref(c, pick.ptr.dev, READ,
+				BCH_DEV_READ_REF_btree_verify_replicas);
 	if (!ca)
 		return false;
 
@@ -57,7 +60,8 @@ static bool bch2_btree_verify_replica(struct bch_fs *c, struct btree *b,
 	submit_bio_wait(bio);
 
 	bio_put(bio);
-	percpu_ref_put(&ca->io_ref[READ]);
+	enumerated_ref_put(&ca->io_ref[READ],
+			   BCH_DEV_READ_REF_btree_verify_replicas);
 
 	memcpy(n_ondisk, n_sorted, btree_buf_bytes(b));
 
@@ -196,7 +200,8 @@ void bch2_btree_node_ondisk_to_text(struct printbuf *out, struct bch_fs *c,
 		return;
 	}
 
-	ca = bch2_dev_get_ioref(c, pick.ptr.dev, READ);
+	ca = bch2_dev_get_ioref(c, pick.ptr.dev, READ,
+			BCH_DEV_READ_REF_btree_node_ondisk_to_text);
 	if (!ca) {
 		prt_printf(out, "error getting device to read from: not online\n");
 		return;
@@ -297,28 +302,13 @@ out:
 	if (bio)
 		bio_put(bio);
 	kvfree(n_ondisk);
-	percpu_ref_put(&ca->io_ref[READ]);
+	enumerated_ref_put(&ca->io_ref[READ],
+			   BCH_DEV_READ_REF_btree_node_ondisk_to_text);
 }
 
 #ifdef CONFIG_DEBUG_FS
 
-/* XXX: bch_fs refcounting */
-
-struct dump_iter {
-	struct bch_fs		*c;
-	enum btree_id		id;
-	struct bpos		from;
-	struct bpos		prev_node;
-	u64			iter;
-
-	struct printbuf		buf;
-
-	char __user		*ubuf;	/* destination user buffer */
-	size_t			size;	/* size of requested read */
-	ssize_t			ret;	/* bytes read so far */
-};
-
-static ssize_t flush_buf(struct dump_iter *i)
+ssize_t bch2_debugfs_flush_buf(struct dump_iter *i)
 {
 	if (i->buf.pos) {
 		size_t bytes = min_t(size_t, i->buf.pos, i->size);
@@ -356,7 +346,7 @@ static int bch2_dump_open(struct inode *inode, struct file *file)
 	return 0;
 }
 
-static int bch2_dump_release(struct inode *inode, struct file *file)
+int bch2_dump_release(struct inode *inode, struct file *file)
 {
 	struct dump_iter *i = file->private_data;
 
@@ -374,7 +364,7 @@ static ssize_t bch2_read_btree(struct file *file, char __user *buf,
 	i->size	= size;
 	i->ret	= 0;
 
-	return flush_buf(i) ?:
+	return bch2_debugfs_flush_buf(i) ?:
 		bch2_trans_run(i->c,
 			for_each_btree_key(trans, iter, i->id, i->from,
 					   BTREE_ITER_prefetch|
@@ -383,7 +373,7 @@ static ssize_t bch2_read_btree(struct file *file, char __user *buf,
 				prt_newline(&i->buf);
 				bch2_trans_unlock(trans);
 				i->from = bpos_successor(iter.pos);
-				flush_buf(i);
+				bch2_debugfs_flush_buf(i);
 			}))) ?:
 		i->ret;
 }
@@ -404,7 +394,7 @@ static ssize_t bch2_read_btree_formats(struct file *file, char __user *buf,
 	i->size	= size;
 	i->ret	= 0;
 
-	ssize_t ret = flush_buf(i);
+	ssize_t ret = bch2_debugfs_flush_buf(i);
 	if (ret)
 		return ret;
 
@@ -418,7 +408,7 @@ static ssize_t bch2_read_btree_formats(struct file *file, char __user *buf,
 				? bpos_successor(b->key.k.p)
 				: b->key.k.p;
 
-			drop_locks_do(trans, flush_buf(i));
+			drop_locks_do(trans, bch2_debugfs_flush_buf(i));
 		}))) ?: i->ret;
 }
 
@@ -438,7 +428,7 @@ static ssize_t bch2_read_bfloat_failed(struct file *file, char __user *buf,
 	i->size	= size;
 	i->ret	= 0;
 
-	return flush_buf(i) ?:
+	return bch2_debugfs_flush_buf(i) ?:
 		bch2_trans_run(i->c,
 			for_each_btree_key(trans, iter, i->id, i->from,
 					   BTREE_ITER_prefetch|
@@ -456,7 +446,7 @@ static ssize_t bch2_read_bfloat_failed(struct file *file, char __user *buf,
 				bch2_bfloat_to_text(&i->buf, l->b, _k);
 				bch2_trans_unlock(trans);
 				i->from = bpos_successor(iter.pos);
-				flush_buf(i);
+				bch2_debugfs_flush_buf(i);
 			}))) ?:
 		i->ret;
 }
@@ -517,7 +507,7 @@ static ssize_t bch2_cached_btree_nodes_read(struct file *file, char __user *buf,
 		struct rhash_head *pos;
 		struct btree *b;
 
-		ret = flush_buf(i);
+		ret = bch2_debugfs_flush_buf(i);
 		if (ret)
 			return ret;
 
@@ -540,7 +530,7 @@ static ssize_t bch2_cached_btree_nodes_read(struct file *file, char __user *buf,
 		ret = -ENOMEM;
 
 	if (!ret)
-		ret = flush_buf(i);
+		ret = bch2_debugfs_flush_buf(i);
 
 	return ret ?: i->ret;
 }
@@ -614,7 +604,7 @@ restart:
 
 		closure_put(&trans->ref);
 
-		ret = flush_buf(i);
+		ret = bch2_debugfs_flush_buf(i);
 		if (ret)
 			goto unlocked;
 
@@ -627,7 +617,7 @@ unlocked:
 		ret = -ENOMEM;
 
 	if (!ret)
-		ret = flush_buf(i);
+		ret = bch2_debugfs_flush_buf(i);
 
 	return ret ?: i->ret;
 }
@@ -652,7 +642,7 @@ static ssize_t bch2_journal_pins_read(struct file *file, char __user *buf,
 	i->ret	= 0;
 
 	while (1) {
-		err = flush_buf(i);
+		err = bch2_debugfs_flush_buf(i);
 		if (err)
 			return err;
 
@@ -695,7 +685,7 @@ static ssize_t bch2_btree_updates_read(struct file *file, char __user *buf,
 		i->iter++;
 	}
 
-	err = flush_buf(i);
+	err = bch2_debugfs_flush_buf(i);
 	if (err)
 		return err;
 
@@ -753,7 +743,7 @@ static ssize_t btree_transaction_stats_read(struct file *file, char __user *buf,
 	while (1) {
 		struct btree_transaction_stats *s = &c->btree_transaction_stats[i->iter];
 
-		err = flush_buf(i);
+		err = bch2_debugfs_flush_buf(i);
 		if (err)
 			return err;
 
@@ -874,7 +864,7 @@ static ssize_t bch2_simple_print(struct file *file, char __user *buf,
 		ret = -ENOMEM;
 
 	if (!ret)
-		ret = flush_buf(i);
+		ret = bch2_debugfs_flush_buf(i);
 
 	return ret ?: i->ret;
 }
@@ -963,6 +953,8 @@ void bch2_fs_debug_init(struct bch_fs *c)
 	debugfs_create_file("write_points", 0400, c->fs_debug_dir,
 			    c->btree_debug, &write_points_ops);
 
+	bch2_fs_async_obj_debugfs_init(c);
+
 	c->btree_debug_dir = debugfs_create_dir("btrees", c->fs_debug_dir);
 	if (IS_ERR_OR_NULL(c->btree_debug_dir))
 		return;
diff --git a/libbcachefs/debug.h b/libbcachefs/debug.h
index 2c37143b..52dbea73 100644
--- a/libbcachefs/debug.h
+++ b/libbcachefs/debug.h
@@ -19,6 +19,24 @@ static inline void bch2_btree_verify(struct bch_fs *c, struct btree *b)
 }
 
 #ifdef CONFIG_DEBUG_FS
+struct dump_iter {
+	struct bch_fs		*c;
+	struct async_obj_list	*list;
+	enum btree_id		id;
+	struct bpos		from;
+	struct bpos		prev_node;
+	u64			iter;
+
+	struct printbuf		buf;
+
+	char __user		*ubuf;	/* destination user buffer */
+	size_t			size;	/* size of requested read */
+	ssize_t			ret;	/* bytes read so far */
+};
+
+ssize_t bch2_debugfs_flush_buf(struct dump_iter *);
+int bch2_dump_release(struct inode *, struct file *);
+
 void bch2_fs_debug_exit(struct bch_fs *);
 void bch2_fs_debug_init(struct bch_fs *);
 #else
diff --git a/libbcachefs/disk_groups.c b/libbcachefs/disk_groups.c
index 1186280b..79688902 100644
--- a/libbcachefs/disk_groups.c
+++ b/libbcachefs/disk_groups.c
@@ -555,14 +555,12 @@ void bch2_target_to_text(struct printbuf *out, struct bch_fs *c, unsigned v)
 			? rcu_dereference(c->devs[t.dev])
 			: NULL;
 
-		if (ca && percpu_ref_tryget(&ca->io_ref[READ])) {
+		if (ca && ca->disk_sb.bdev)
 			prt_printf(out, "/dev/%s", ca->name);
-			percpu_ref_put(&ca->io_ref[READ]);
-		} else if (ca) {
+		else if (ca)
 			prt_printf(out, "offline device %u", t.dev);
-		} else {
+		else
 			prt_printf(out, "invalid device %u", t.dev);
-		}
 
 		rcu_read_unlock();
 		out->atomic--;
diff --git a/libbcachefs/ec.c b/libbcachefs/ec.c
index 42600370..1dde0a03 100644
--- a/libbcachefs/ec.c
+++ b/libbcachefs/ec.c
@@ -16,6 +16,7 @@
 #include "disk_accounting.h"
 #include "disk_groups.h"
 #include "ec.h"
+#include "enumerated_ref.h"
 #include "error.h"
 #include "io_read.h"
 #include "io_write.h"
@@ -706,6 +707,9 @@ static void ec_block_endio(struct bio *bio)
 	struct bch_dev *ca = ec_bio->ca;
 	struct closure *cl = bio->bi_private;
 	int rw = ec_bio->rw;
+	unsigned ref = rw == READ
+		? BCH_DEV_READ_REF_ec_block
+		: BCH_DEV_WRITE_REF_ec_block;
 
 	bch2_account_io_completion(ca, bio_data_dir(bio),
 				   ec_bio->submit_time, !bio->bi_status);
@@ -727,7 +731,7 @@ static void ec_block_endio(struct bio *bio)
 	}
 
 	bio_put(&ec_bio->bio);
-	percpu_ref_put(&ca->io_ref[rw]);
+	enumerated_ref_put(&ca->io_ref[rw], ref);
 	closure_put(cl);
 }
 
@@ -741,8 +745,11 @@ static void ec_block_io(struct bch_fs *c, struct ec_stripe_buf *buf,
 		? BCH_DATA_user
 		: BCH_DATA_parity;
 	int rw = op_is_write(opf);
+	unsigned ref = rw == READ
+		? BCH_DEV_READ_REF_ec_block
+		: BCH_DEV_WRITE_REF_ec_block;
 
-	struct bch_dev *ca = bch2_dev_get_ioref(c, ptr->dev, rw);
+	struct bch_dev *ca = bch2_dev_get_ioref(c, ptr->dev, rw, ref);
 	if (!ca) {
 		clear_bit(idx, buf->valid);
 		return;
@@ -788,14 +795,14 @@ static void ec_block_io(struct bch_fs *c, struct ec_stripe_buf *buf,
 		bch2_bio_map(&ec_bio->bio, buf->data[idx] + offset, b);
 
 		closure_get(cl);
-		percpu_ref_get(&ca->io_ref[rw]);
+		enumerated_ref_get(&ca->io_ref[rw], ref);
 
 		submit_bio(&ec_bio->bio);
 
 		offset += b;
 	}
 
-	percpu_ref_put(&ca->io_ref[rw]);
+	enumerated_ref_put(&ca->io_ref[rw], ref);
 }
 
 static int get_stripe_key_trans(struct btree_trans *trans, u64 idx,
@@ -1017,14 +1024,14 @@ static void ec_stripe_delete_work(struct work_struct *work)
 				BCH_TRANS_COMMIT_no_enospc, ({
 			ec_stripe_delete(trans, lru_k.k->p.offset);
 		})));
-	bch2_write_ref_put(c, BCH_WRITE_REF_stripe_delete);
+	enumerated_ref_put(&c->writes, BCH_WRITE_REF_stripe_delete);
 }
 
 void bch2_do_stripe_deletes(struct bch_fs *c)
 {
-	if (bch2_write_ref_tryget(c, BCH_WRITE_REF_stripe_delete) &&
+	if (enumerated_ref_tryget(&c->writes, BCH_WRITE_REF_stripe_delete) &&
 	    !queue_work(c->write_ref_wq, &c->ec_stripe_delete_work))
-		bch2_write_ref_put(c, BCH_WRITE_REF_stripe_delete);
+		enumerated_ref_put(&c->writes, BCH_WRITE_REF_stripe_delete);
 }
 
 /* stripe creation: */
@@ -1252,7 +1259,8 @@ static void zero_out_rest_of_ec_bucket(struct bch_fs *c,
 				       unsigned block,
 				       struct open_bucket *ob)
 {
-	struct bch_dev *ca = bch2_dev_get_ioref(c, ob->dev, WRITE);
+	struct bch_dev *ca = bch2_dev_get_ioref(c, ob->dev, WRITE,
+				BCH_DEV_WRITE_REF_ec_bucket_zero);
 	if (!ca) {
 		s->err = -BCH_ERR_erofs_no_writes;
 		return;
@@ -1268,7 +1276,7 @@ static void zero_out_rest_of_ec_bucket(struct bch_fs *c,
 			ob->sectors_free,
 			GFP_KERNEL, 0);
 
-	percpu_ref_put(&ca->io_ref[WRITE]);
+	enumerated_ref_put(&ca->io_ref[WRITE], BCH_DEV_WRITE_REF_ec_bucket_zero);
 
 	if (ret)
 		s->err = ret;
@@ -1418,15 +1426,15 @@ static void ec_stripe_create_work(struct work_struct *work)
 	while ((s = get_pending_stripe(c)))
 		ec_stripe_create(s);
 
-	bch2_write_ref_put(c, BCH_WRITE_REF_stripe_create);
+	enumerated_ref_put(&c->writes, BCH_WRITE_REF_stripe_create);
 }
 
 void bch2_ec_do_stripe_creates(struct bch_fs *c)
 {
-	bch2_write_ref_get(c, BCH_WRITE_REF_stripe_create);
+	enumerated_ref_get(&c->writes, BCH_WRITE_REF_stripe_create);
 
 	if (!queue_work(system_long_wq, &c->ec_stripe_create_work))
-		bch2_write_ref_put(c, BCH_WRITE_REF_stripe_create);
+		enumerated_ref_put(&c->writes, BCH_WRITE_REF_stripe_create);
 }
 
 static void ec_stripe_new_set_pending(struct bch_fs *c, struct ec_stripe_head *h)
diff --git a/libbcachefs/enumerated_ref.c b/libbcachefs/enumerated_ref.c
new file mode 100644
index 00000000..56ab430f
--- /dev/null
+++ b/libbcachefs/enumerated_ref.c
@@ -0,0 +1,144 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "bcachefs.h"
+#include "enumerated_ref.h"
+#include "util.h"
+
+#include <linux/completion.h>
+
+#ifdef ENUMERATED_REF_DEBUG
+void enumerated_ref_get(struct enumerated_ref *ref, unsigned idx)
+{
+	BUG_ON(idx >= ref->nr);
+	atomic_long_inc(&ref->refs[idx]);
+}
+
+bool __enumerated_ref_tryget(struct enumerated_ref *ref, unsigned idx)
+{
+	BUG_ON(idx >= ref->nr);
+	return atomic_long_inc_not_zero(&ref->refs[idx]);
+}
+
+bool enumerated_ref_tryget(struct enumerated_ref *ref, unsigned idx)
+{
+	BUG_ON(idx >= ref->nr);
+	return !ref->dying &&
+		atomic_long_inc_not_zero(&ref->refs[idx]);
+}
+
+void enumerated_ref_put(struct enumerated_ref *ref, unsigned idx)
+{
+	BUG_ON(idx >= ref->nr);
+	long v = atomic_long_dec_return(&ref->refs[idx]);
+
+	BUG_ON(v < 0);
+	if (v)
+		return;
+
+	for (unsigned i = 0; i < ref->nr; i++)
+		if (atomic_long_read(&ref->refs[i]))
+			return;
+
+	if (ref->stop_fn)
+		ref->stop_fn(ref);
+	complete(&ref->stop_complete);
+}
+#endif
+
+#ifndef ENUMERATED_REF_DEBUG
+static void enumerated_ref_kill_cb(struct percpu_ref *percpu_ref)
+{
+	struct enumerated_ref *ref =
+		container_of(percpu_ref, struct enumerated_ref, ref);
+
+	if (ref->stop_fn)
+		ref->stop_fn(ref);
+	complete(&ref->stop_complete);
+}
+#endif
+
+void enumerated_ref_stop_async(struct enumerated_ref *ref)
+{
+	reinit_completion(&ref->stop_complete);
+
+#ifndef ENUMERATED_REF_DEBUG
+	percpu_ref_kill(&ref->ref);
+#else
+	ref->dying = true;
+	for (unsigned i = 0; i < ref->nr; i++)
+		enumerated_ref_put(ref, i);
+#endif
+}
+
+void enumerated_ref_stop(struct enumerated_ref *ref,
+			 const char * const names[])
+{
+	enumerated_ref_stop_async(ref);
+	while (!wait_for_completion_timeout(&ref->stop_complete, HZ * 10)) {
+		struct printbuf buf = PRINTBUF;
+
+		prt_str(&buf, "Waited for 10 seconds to shutdown enumerated ref\n");
+		prt_str(&buf, "Outstanding refs:\n");
+		enumerated_ref_to_text(&buf, ref, names);
+		printk(KERN_ERR "%s", buf.buf);
+		printbuf_exit(&buf);
+	}
+}
+
+void enumerated_ref_start(struct enumerated_ref *ref)
+{
+#ifndef ENUMERATED_REF_DEBUG
+	percpu_ref_reinit(&ref->ref);
+#else
+	ref->dying = false;
+	for (unsigned i = 0; i < ref->nr; i++) {
+		BUG_ON(atomic_long_read(&ref->refs[i]));
+		atomic_long_inc(&ref->refs[i]);
+	}
+#endif
+}
+
+void enumerated_ref_exit(struct enumerated_ref *ref)
+{
+#ifndef ENUMERATED_REF_DEBUG
+	percpu_ref_exit(&ref->ref);
+#else
+	kfree(ref->refs);
+	ref->refs = NULL;
+	ref->nr = 0;
+#endif
+}
+
+int enumerated_ref_init(struct enumerated_ref *ref, unsigned nr,
+			void (*stop_fn)(struct enumerated_ref *))
+{
+	init_completion(&ref->stop_complete);
+	ref->stop_fn = stop_fn;
+
+#ifndef ENUMERATED_REF_DEBUG
+	return percpu_ref_init(&ref->ref, enumerated_ref_kill_cb,
+			    PERCPU_REF_INIT_DEAD, GFP_KERNEL);
+#else
+	ref->refs = kzalloc(sizeof(ref->refs[0]) * nr, GFP_KERNEL);
+	if (!ref->refs)
+		return -ENOMEM;
+
+	ref->nr = nr;
+	return 0;
+#endif
+}
+
+void enumerated_ref_to_text(struct printbuf *out,
+			    struct enumerated_ref *ref,
+			    const char * const names[])
+{
+#ifdef ENUMERATED_REF_DEBUG
+	bch2_printbuf_tabstop_push(out, 32);
+
+	for (unsigned i = 0; i < ref->nr; i++)
+		prt_printf(out, "%s\t%li\n", names[i],
+			   atomic_long_read(&ref->refs[i]));
+#else
+	prt_str(out, "(not in debug mode)\n");
+#endif
+}
diff --git a/libbcachefs/enumerated_ref.h b/libbcachefs/enumerated_ref.h
new file mode 100644
index 00000000..ec01cf59
--- /dev/null
+++ b/libbcachefs/enumerated_ref.h
@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _BCACHEFS_ENUMERATED_REF_H
+#define _BCACHEFS_ENUMERATED_REF_H
+
+#include "enumerated_ref_types.h"
+
+/*
+ * A refcount where the users are enumerated: in debug mode, we create sepate
+ * refcounts for each user, to make leaks and refcount errors easy to track
+ * down:
+ */
+
+#ifdef ENUMERATED_REF_DEBUG
+void enumerated_ref_get(struct enumerated_ref *, unsigned);
+bool __enumerated_ref_tryget(struct enumerated_ref *, unsigned);
+bool enumerated_ref_tryget(struct enumerated_ref *, unsigned);
+void enumerated_ref_put(struct enumerated_ref *, unsigned);
+#else
+
+static inline void enumerated_ref_get(struct enumerated_ref *ref, unsigned idx)
+{
+	percpu_ref_get(&ref->ref);
+}
+
+static inline bool __enumerated_ref_tryget(struct enumerated_ref *ref, unsigned idx)
+{
+	return percpu_ref_tryget(&ref->ref);
+}
+
+static inline bool enumerated_ref_tryget(struct enumerated_ref *ref, unsigned idx)
+{
+	return percpu_ref_tryget_live(&ref->ref);
+}
+
+static inline void enumerated_ref_put(struct enumerated_ref *ref, unsigned idx)
+{
+	percpu_ref_put(&ref->ref);
+}
+#endif
+
+static inline bool enumerated_ref_is_zero(struct enumerated_ref *ref)
+{
+#ifndef ENUMERATED_REF_DEBUG
+	return percpu_ref_is_zero(&ref->ref);
+#else
+	for (unsigned i = 0; i < ref->nr; i++)
+		if (atomic_long_read(&ref->refs[i]))
+			return false;
+	return true;
+#endif
+}
+
+void enumerated_ref_stop_async(struct enumerated_ref *);
+void enumerated_ref_stop(struct enumerated_ref *, const char * const[]);
+void enumerated_ref_start(struct enumerated_ref *);
+
+void enumerated_ref_exit(struct enumerated_ref *);
+int enumerated_ref_init(struct enumerated_ref *, unsigned,
+			void (*stop_fn)(struct enumerated_ref *));
+
+struct printbuf;
+void enumerated_ref_to_text(struct printbuf *,
+			    struct enumerated_ref *,
+			    const char * const[]);
+
+#endif /* _BCACHEFS_ENUMERATED_REF_H */
diff --git a/libbcachefs/enumerated_ref_types.h b/libbcachefs/enumerated_ref_types.h
new file mode 100644
index 00000000..0e6076f4
--- /dev/null
+++ b/libbcachefs/enumerated_ref_types.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _BCACHEFS_ENUMERATED_REF_TYPES_H
+#define _BCACHEFS_ENUMERATED_REF_TYPES_H
+
+#include <linux/percpu-refcount.h>
+
+struct enumerated_ref {
+#ifdef ENUMERATED_REF_DEBUG
+	unsigned		nr;
+	bool			dying;
+	atomic_long_t		*refs;
+#else
+	struct percpu_ref	ref;
+#endif
+	void			(*stop_fn)(struct enumerated_ref *);
+	struct completion	stop_complete;
+};
+
+#endif /* _BCACHEFS_ENUMERATED_REF_TYPES_H */
diff --git a/libbcachefs/errcode.h b/libbcachefs/errcode.h
index 996cdf62..83ed5a63 100644
--- a/libbcachefs/errcode.h
+++ b/libbcachefs/errcode.h
@@ -53,6 +53,7 @@
 	x(ENOMEM,			ENOMEM_dio_write_bioset_init)		\
 	x(ENOMEM,			ENOMEM_nocow_flush_bioset_init)		\
 	x(ENOMEM,			ENOMEM_promote_table_init)		\
+	x(ENOMEM,			ENOMEM_async_obj_init)			\
 	x(ENOMEM,			ENOMEM_compression_bounce_read_init)	\
 	x(ENOMEM,			ENOMEM_compression_bounce_write_init)	\
 	x(ENOMEM,			ENOMEM_compression_workspace_init)	\
diff --git a/libbcachefs/fast_list.h b/libbcachefs/fast_list.h
new file mode 100644
index 00000000..73c9bf59
--- /dev/null
+++ b/libbcachefs/fast_list.h
@@ -0,0 +1,41 @@
+#ifndef _LINUX_FAST_LIST_H
+#define _LINUX_FAST_LIST_H
+
+#include <linux/generic-radix-tree.h>
+#include <linux/idr.h>
+#include <linux/percpu.h>
+
+struct fast_list_pcpu;
+
+struct fast_list {
+	GENRADIX(void *)	items;
+	struct ida		slots_allocated;;
+	struct fast_list_pcpu __percpu
+				*buffer;
+};
+
+static inline void *fast_list_iter_peek(struct genradix_iter *iter,
+					struct fast_list *list)
+{
+	void **p;
+	while ((p = genradix_iter_peek(iter, &list->items)) && !*p)
+		genradix_iter_advance(iter, &list->items);
+
+	return p ? *p : NULL;
+}
+
+#define fast_list_for_each_from(_list, _iter, _i, _start)		\
+	for (_iter = genradix_iter_init(&(_list)->items, _start);	\
+	     (_i = fast_list_iter_peek(&(_iter), _list)) != NULL;	\
+	     genradix_iter_advance(&(_iter), &(_list)->items))
+
+#define fast_list_for_each(_list, _iter, _i)				\
+	fast_list_for_each_from(_list, _iter, _i, 0)
+
+int fast_list_get_idx(struct fast_list *l);
+int fast_list_add(struct fast_list *l, void *item);
+void fast_list_remove(struct fast_list *l, unsigned idx);
+void fast_list_exit(struct fast_list *l);
+int fast_list_init(struct fast_list *l);
+
+#endif /* _LINUX_FAST_LIST_H */
diff --git a/libbcachefs/fs-io-direct.c b/libbcachefs/fs-io-direct.c
index 535bc5fc..1f5154d9 100644
--- a/libbcachefs/fs-io-direct.c
+++ b/libbcachefs/fs-io-direct.c
@@ -3,6 +3,7 @@
 
 #include "bcachefs.h"
 #include "alloc_foreground.h"
+#include "enumerated_ref.h"
 #include "fs.h"
 #include "fs-io.h"
 #include "fs-io-direct.h"
@@ -401,7 +402,7 @@ static __always_inline long bch2_dio_write_done(struct dio_write *dio)
 	ret = dio->op.error ?: ((long) dio->written << 9);
 	bio_put(&dio->op.wbio.bio);
 
-	bch2_write_ref_put(c, BCH_WRITE_REF_dio_write);
+	enumerated_ref_put(&c->writes, BCH_WRITE_REF_dio_write);
 
 	/* inode->i_dio_count is our ref on inode and thus bch_fs */
 	inode_dio_end(&inode->v);
@@ -606,7 +607,7 @@ ssize_t bch2_direct_write(struct kiocb *req, struct iov_iter *iter)
 	prefetch(&inode->ei_inode);
 	prefetch((void *) &inode->ei_inode + 64);
 
-	if (!bch2_write_ref_tryget(c, BCH_WRITE_REF_dio_write))
+	if (!enumerated_ref_tryget(&c->writes, BCH_WRITE_REF_dio_write))
 		return -EROFS;
 
 	inode_lock(&inode->v);
@@ -675,7 +676,7 @@ err_put_bio:
 	bio_put(bio);
 	inode_dio_end(&inode->v);
 err_put_write_ref:
-	bch2_write_ref_put(c, BCH_WRITE_REF_dio_write);
+	enumerated_ref_put(&c->writes, BCH_WRITE_REF_dio_write);
 	goto out;
 }
 
diff --git a/libbcachefs/fs-io.c b/libbcachefs/fs-io.c
index 409bba39..801e9cd6 100644
--- a/libbcachefs/fs-io.c
+++ b/libbcachefs/fs-io.c
@@ -7,6 +7,7 @@
 #include "btree_update.h"
 #include "buckets.h"
 #include "clock.h"
+#include "enumerated_ref.h"
 #include "error.h"
 #include "extents.h"
 #include "extent_update.h"
@@ -48,7 +49,8 @@ static void nocow_flush_endio(struct bio *_bio)
 	struct nocow_flush *bio = container_of(_bio, struct nocow_flush, bio);
 
 	closure_put(bio->cl);
-	percpu_ref_put(&bio->ca->io_ref[WRITE]);
+	enumerated_ref_put(&bio->ca->io_ref[WRITE],
+			   BCH_DEV_WRITE_REF_nocow_flush);
 	bio_put(&bio->bio);
 }
 
@@ -71,7 +73,8 @@ void bch2_inode_flush_nocow_writes_async(struct bch_fs *c,
 	for_each_set_bit(dev, devs.d, BCH_SB_MEMBERS_MAX) {
 		rcu_read_lock();
 		ca = rcu_dereference(c->devs[dev]);
-		if (ca && !percpu_ref_tryget(&ca->io_ref[WRITE]))
+		if (ca && !enumerated_ref_tryget(&ca->io_ref[WRITE],
+					BCH_DEV_WRITE_REF_nocow_flush))
 			ca = NULL;
 		rcu_read_unlock();
 
@@ -205,7 +208,7 @@ static int bch2_flush_inode(struct bch_fs *c,
 	if (c->opts.journal_flush_disabled)
 		return 0;
 
-	if (!bch2_write_ref_tryget(c, BCH_WRITE_REF_fsync))
+	if (!enumerated_ref_tryget(&c->writes, BCH_WRITE_REF_fsync))
 		return -EROFS;
 
 	u64 seq;
@@ -213,7 +216,7 @@ static int bch2_flush_inode(struct bch_fs *c,
 			bch2_get_inode_journal_seq_trans(trans, inode_inum(inode), &seq)) ?:
 		  bch2_journal_flush_seq(&c->journal, seq, TASK_INTERRUPTIBLE) ?:
 		  bch2_inode_flush_nocow_writes(c, inode);
-	bch2_write_ref_put(c, BCH_WRITE_REF_fsync);
+	enumerated_ref_put(&c->writes, BCH_WRITE_REF_fsync);
 	return ret;
 }
 
@@ -796,7 +799,7 @@ long bch2_fallocate_dispatch(struct file *file, int mode,
 	struct bch_fs *c = inode->v.i_sb->s_fs_info;
 	long ret;
 
-	if (!bch2_write_ref_tryget(c, BCH_WRITE_REF_fallocate))
+	if (!enumerated_ref_tryget(&c->writes, BCH_WRITE_REF_fallocate))
 		return -EROFS;
 
 	inode_lock(&inode->v);
@@ -820,7 +823,7 @@ long bch2_fallocate_dispatch(struct file *file, int mode,
 err:
 	bch2_pagecache_block_put(inode);
 	inode_unlock(&inode->v);
-	bch2_write_ref_put(c, BCH_WRITE_REF_fallocate);
+	enumerated_ref_put(&c->writes, BCH_WRITE_REF_fallocate);
 
 	return bch2_err_class(ret);
 }
diff --git a/libbcachefs/fs-ioctl.c b/libbcachefs/fs-ioctl.c
index 14886e1d..a82dfce9 100644
--- a/libbcachefs/fs-ioctl.c
+++ b/libbcachefs/fs-ioctl.c
@@ -21,206 +21,6 @@
 #define FSOP_GOING_FLAGS_LOGFLUSH	0x1	/* flush log but not data */
 #define FSOP_GOING_FLAGS_NOLOGFLUSH	0x2	/* don't flush log nor data */
 
-struct flags_set {
-	unsigned		mask;
-	unsigned		flags;
-
-	unsigned		projid;
-
-	bool			set_projinherit;
-	bool			projinherit;
-};
-
-static int bch2_inode_flags_set(struct btree_trans *trans,
-				struct bch_inode_info *inode,
-				struct bch_inode_unpacked *bi,
-				void *p)
-{
-	struct bch_fs *c = inode->v.i_sb->s_fs_info;
-	/*
-	 * We're relying on btree locking here for exclusion with other ioctl
-	 * calls - use the flags in the btree (@bi), not inode->i_flags:
-	 */
-	struct flags_set *s = p;
-	unsigned newflags = s->flags;
-	unsigned oldflags = bi->bi_flags & s->mask;
-
-	if (((newflags ^ oldflags) & (BCH_INODE_append|BCH_INODE_immutable)) &&
-	    !capable(CAP_LINUX_IMMUTABLE))
-		return -EPERM;
-
-	if (!S_ISREG(bi->bi_mode) &&
-	    !S_ISDIR(bi->bi_mode) &&
-	    (newflags & (BCH_INODE_nodump|BCH_INODE_noatime)) != newflags)
-		return -EINVAL;
-
-	if ((newflags ^ oldflags) & BCH_INODE_casefolded) {
-#ifdef CONFIG_UNICODE
-		int ret = 0;
-		/* Not supported on individual files. */
-		if (!S_ISDIR(bi->bi_mode))
-			return -EOPNOTSUPP;
-
-		/*
-		 * Make sure the dir is empty, as otherwise we'd need to
-		 * rehash everything and update the dirent keys.
-		 */
-		ret = bch2_empty_dir_trans(trans, inode_inum(inode));
-		if (ret < 0)
-			return ret;
-
-		ret = bch2_request_incompat_feature(c, bcachefs_metadata_version_casefolding);
-		if (ret)
-			return ret;
-
-		bch2_check_set_feature(c, BCH_FEATURE_casefolding);
-#else
-		printk(KERN_ERR "Cannot use casefolding on a kernel without CONFIG_UNICODE\n");
-		return -EOPNOTSUPP;
-#endif
-	}
-
-	if (s->set_projinherit) {
-		bi->bi_fields_set &= ~(1 << Inode_opt_project);
-		bi->bi_fields_set |= ((int) s->projinherit << Inode_opt_project);
-	}
-
-	bi->bi_flags &= ~s->mask;
-	bi->bi_flags |= newflags;
-
-	bi->bi_ctime = timespec_to_bch2_time(c, current_time(&inode->v));
-	return 0;
-}
-
-static int bch2_ioc_getflags(struct bch_inode_info *inode, int __user *arg)
-{
-	unsigned flags = map_flags(bch_flags_to_uflags, inode->ei_inode.bi_flags);
-
-	return put_user(flags, arg);
-}
-
-static int bch2_ioc_setflags(struct bch_fs *c,
-			     struct file *file,
-			     struct bch_inode_info *inode,
-			     void __user *arg)
-{
-	struct flags_set s = { .mask = map_defined(bch_flags_to_uflags) };
-	unsigned uflags;
-	int ret;
-
-	if (get_user(uflags, (int __user *) arg))
-		return -EFAULT;
-
-	s.flags = map_flags_rev(bch_flags_to_uflags, uflags);
-	if (uflags)
-		return -EOPNOTSUPP;
-
-	ret = mnt_want_write_file(file);
-	if (ret)
-		return ret;
-
-	inode_lock(&inode->v);
-	if (!inode_owner_or_capable(file_mnt_idmap(file), &inode->v)) {
-		ret = -EACCES;
-		goto setflags_out;
-	}
-
-	mutex_lock(&inode->ei_update_lock);
-	ret   = bch2_subvol_is_ro(c, inode->ei_inum.subvol) ?:
-		bch2_write_inode(c, inode, bch2_inode_flags_set, &s,
-			       ATTR_CTIME);
-	mutex_unlock(&inode->ei_update_lock);
-
-setflags_out:
-	inode_unlock(&inode->v);
-	mnt_drop_write_file(file);
-	return ret;
-}
-
-static int bch2_ioc_fsgetxattr(struct bch_inode_info *inode,
-			       struct fsxattr __user *arg)
-{
-	struct fsxattr fa = { 0 };
-
-	fa.fsx_xflags = map_flags(bch_flags_to_xflags, inode->ei_inode.bi_flags);
-
-	if (inode->ei_inode.bi_fields_set & (1 << Inode_opt_project))
-		fa.fsx_xflags |= FS_XFLAG_PROJINHERIT;
-
-	fa.fsx_projid = inode->ei_qid.q[QTYP_PRJ];
-
-	if (copy_to_user(arg, &fa, sizeof(fa)))
-		return -EFAULT;
-
-	return 0;
-}
-
-static int fssetxattr_inode_update_fn(struct btree_trans *trans,
-				      struct bch_inode_info *inode,
-				      struct bch_inode_unpacked *bi,
-				      void *p)
-{
-	struct flags_set *s = p;
-
-	if (s->projid != bi->bi_project) {
-		bi->bi_fields_set |= 1U << Inode_opt_project;
-		bi->bi_project = s->projid;
-	}
-
-	return bch2_inode_flags_set(trans, inode, bi, p);
-}
-
-static int bch2_ioc_fssetxattr(struct bch_fs *c,
-			       struct file *file,
-			       struct bch_inode_info *inode,
-			       struct fsxattr __user *arg)
-{
-	struct flags_set s = { .mask = map_defined(bch_flags_to_xflags) };
-	struct fsxattr fa;
-	int ret;
-
-	if (copy_from_user(&fa, arg, sizeof(fa)))
-		return -EFAULT;
-
-	s.set_projinherit = true;
-	s.projinherit = (fa.fsx_xflags & FS_XFLAG_PROJINHERIT) != 0;
-	fa.fsx_xflags &= ~FS_XFLAG_PROJINHERIT;
-
-	s.flags = map_flags_rev(bch_flags_to_xflags, fa.fsx_xflags);
-	if (fa.fsx_xflags)
-		return -EOPNOTSUPP;
-
-	if (fa.fsx_projid >= U32_MAX)
-		return -EINVAL;
-
-	/*
-	 * inode fields accessible via the xattr interface are stored with a +1
-	 * bias, so that 0 means unset:
-	 */
-	s.projid = fa.fsx_projid + 1;
-
-	ret = mnt_want_write_file(file);
-	if (ret)
-		return ret;
-
-	inode_lock(&inode->v);
-	if (!inode_owner_or_capable(file_mnt_idmap(file), &inode->v)) {
-		ret = -EACCES;
-		goto err;
-	}
-
-	mutex_lock(&inode->ei_update_lock);
-	ret   = bch2_subvol_is_ro(c, inode->ei_inum.subvol) ?:
-		bch2_set_projid(c, inode, fa.fsx_projid) ?:
-		bch2_write_inode(c, inode, fssetxattr_inode_update_fn, &s,
-			       ATTR_CTIME);
-	mutex_unlock(&inode->ei_update_lock);
-err:
-	inode_unlock(&inode->v);
-	mnt_drop_write_file(file);
-	return ret;
-}
-
 static int bch2_reinherit_attrs_fn(struct btree_trans *trans,
 				   struct bch_inode_info *inode,
 				   struct bch_inode_unpacked *bi,
@@ -558,23 +358,6 @@ long bch2_fs_file_ioctl(struct file *file, unsigned cmd, unsigned long arg)
 	long ret;
 
 	switch (cmd) {
-	case FS_IOC_GETFLAGS:
-		ret = bch2_ioc_getflags(inode, (int __user *) arg);
-		break;
-
-	case FS_IOC_SETFLAGS:
-		ret = bch2_ioc_setflags(c, file, inode, (int __user *) arg);
-		break;
-
-	case FS_IOC_FSGETXATTR:
-		ret = bch2_ioc_fsgetxattr(inode, (void __user *) arg);
-		break;
-
-	case FS_IOC_FSSETXATTR:
-		ret = bch2_ioc_fssetxattr(c, file, inode,
-					  (void __user *) arg);
-		break;
-
 	case BCHFS_IOC_REINHERIT_ATTRS:
 		ret = bch2_ioc_reinherit_attrs(c, file, inode,
 					       (void __user *) arg);
diff --git a/libbcachefs/fs-ioctl.h b/libbcachefs/fs-ioctl.h
index ecd3bfdc..a657e499 100644
--- a/libbcachefs/fs-ioctl.h
+++ b/libbcachefs/fs-ioctl.h
@@ -2,81 +2,6 @@
 #ifndef _BCACHEFS_FS_IOCTL_H
 #define _BCACHEFS_FS_IOCTL_H
 
-/* Inode flags: */
-
-/* bcachefs inode flags -> vfs inode flags: */
-static const __maybe_unused unsigned bch_flags_to_vfs[] = {
-	[__BCH_INODE_sync]		= S_SYNC,
-	[__BCH_INODE_immutable]		= S_IMMUTABLE,
-	[__BCH_INODE_append]		= S_APPEND,
-	[__BCH_INODE_noatime]		= S_NOATIME,
-	[__BCH_INODE_casefolded]	= S_CASEFOLD,
-};
-
-/* bcachefs inode flags -> FS_IOC_GETFLAGS: */
-static const __maybe_unused unsigned bch_flags_to_uflags[] = {
-	[__BCH_INODE_sync]		= FS_SYNC_FL,
-	[__BCH_INODE_immutable]		= FS_IMMUTABLE_FL,
-	[__BCH_INODE_append]		= FS_APPEND_FL,
-	[__BCH_INODE_nodump]		= FS_NODUMP_FL,
-	[__BCH_INODE_noatime]		= FS_NOATIME_FL,
-	[__BCH_INODE_casefolded]	= FS_CASEFOLD_FL,
-};
-
-/* bcachefs inode flags -> FS_IOC_FSGETXATTR: */
-static const __maybe_unused unsigned bch_flags_to_xflags[] = {
-	[__BCH_INODE_sync]	= FS_XFLAG_SYNC,
-	[__BCH_INODE_immutable]	= FS_XFLAG_IMMUTABLE,
-	[__BCH_INODE_append]	= FS_XFLAG_APPEND,
-	[__BCH_INODE_nodump]	= FS_XFLAG_NODUMP,
-	[__BCH_INODE_noatime]	= FS_XFLAG_NOATIME,
-	//[__BCH_INODE_PROJINHERIT] = FS_XFLAG_PROJINHERIT;
-};
-
-#define set_flags(_map, _in, _out)					\
-do {									\
-	unsigned _i;							\
-									\
-	for (_i = 0; _i < ARRAY_SIZE(_map); _i++)			\
-		if ((_in) & (1 << _i))					\
-			(_out) |= _map[_i];				\
-		else							\
-			(_out) &= ~_map[_i];				\
-} while (0)
-
-#define map_flags(_map, _in)						\
-({									\
-	unsigned _out = 0;						\
-									\
-	set_flags(_map, _in, _out);					\
-	_out;								\
-})
-
-#define map_flags_rev(_map, _in)					\
-({									\
-	unsigned _i, _out = 0;						\
-									\
-	for (_i = 0; _i < ARRAY_SIZE(_map); _i++)			\
-		if ((_in) & _map[_i]) {					\
-			(_out) |= 1 << _i;				\
-			(_in) &= ~_map[_i];				\
-		}							\
-	(_out);								\
-})
-
-#define map_defined(_map)						\
-({									\
-	unsigned _in = ~0;						\
-									\
-	map_flags_rev(_map, _in);					\
-})
-
-/* Set VFS inode flags from bcachefs inode: */
-static inline void bch2_inode_flags_to_vfs(struct bch_inode_info *inode)
-{
-	set_flags(bch_flags_to_vfs, inode->ei_inode.bi_flags, inode->v.i_flags);
-}
-
 long bch2_fs_file_ioctl(struct file *, unsigned, unsigned long);
 long bch2_compat_fs_ioctl(struct file *, unsigned, unsigned long);
 
diff --git a/libbcachefs/fs.c b/libbcachefs/fs.c
index b032ec7a..0422dcab 100644
--- a/libbcachefs/fs.c
+++ b/libbcachefs/fs.c
@@ -33,6 +33,7 @@
 #include <linux/backing-dev.h>
 #include <linux/exportfs.h>
 #include <linux/fiemap.h>
+#include <linux/fileattr.h>
 #include <linux/fs_context.h>
 #include <linux/module.h>
 #include <linux/pagemap.h>
@@ -51,6 +52,22 @@ static void bch2_vfs_inode_init(struct btree_trans *, subvol_inum,
 				struct bch_inode_unpacked *,
 				struct bch_subvolume *);
 
+/* Set VFS inode flags from bcachefs inode: */
+static inline void bch2_inode_flags_to_vfs(struct bch_inode_info *inode)
+{
+	static const __maybe_unused unsigned bch_flags_to_vfs[] = {
+		[__BCH_INODE_sync]		= S_SYNC,
+		[__BCH_INODE_immutable]		= S_IMMUTABLE,
+		[__BCH_INODE_append]		= S_APPEND,
+		[__BCH_INODE_noatime]		= S_NOATIME,
+	};
+
+	set_flags(bch_flags_to_vfs, inode->ei_inode.bi_flags, inode->v.i_flags);
+
+	if (inode->ei_inode.bi_casefold)
+		inode->v.i_flags |= S_CASEFOLD;
+}
+
 void bch2_inode_update_after_write(struct btree_trans *trans,
 				   struct bch_inode_info *inode,
 				   struct bch_inode_unpacked *bi,
@@ -1448,6 +1465,165 @@ static int bch2_open(struct inode *vinode, struct file *file)
 	return generic_file_open(vinode, file);
 }
 
+/* bcachefs inode flags -> FS_IOC_GETFLAGS: */
+static const __maybe_unused unsigned bch_flags_to_uflags[] = {
+	[__BCH_INODE_sync]		= FS_SYNC_FL,
+	[__BCH_INODE_immutable]		= FS_IMMUTABLE_FL,
+	[__BCH_INODE_append]		= FS_APPEND_FL,
+	[__BCH_INODE_nodump]		= FS_NODUMP_FL,
+	[__BCH_INODE_noatime]		= FS_NOATIME_FL,
+};
+
+/* bcachefs inode flags -> FS_IOC_FSGETXATTR: */
+static const __maybe_unused unsigned bch_flags_to_xflags[] = {
+	[__BCH_INODE_sync]	= FS_XFLAG_SYNC,
+	[__BCH_INODE_immutable]	= FS_XFLAG_IMMUTABLE,
+	[__BCH_INODE_append]	= FS_XFLAG_APPEND,
+	[__BCH_INODE_nodump]	= FS_XFLAG_NODUMP,
+	[__BCH_INODE_noatime]	= FS_XFLAG_NOATIME,
+};
+
+static int bch2_fileattr_get(struct dentry *dentry,
+			     struct fileattr *fa)
+{
+	struct bch_inode_info *inode = to_bch_ei(d_inode(dentry));
+
+	fileattr_fill_xflags(fa, map_flags(bch_flags_to_xflags, inode->ei_inode.bi_flags));
+
+	if (inode->ei_inode.bi_fields_set & (1 << Inode_opt_project))
+		fa->fsx_xflags |= FS_XFLAG_PROJINHERIT;
+
+	if (inode->ei_inode.bi_casefold)
+		fa->flags |= FS_CASEFOLD_FL;
+
+	fa->fsx_projid = inode->ei_qid.q[QTYP_PRJ];
+	return 0;
+}
+
+struct flags_set {
+	unsigned		mask;
+	unsigned		flags;
+	unsigned		projid;
+	bool			set_project;
+	bool			set_casefold;
+	bool			casefold;
+};
+
+static int fssetxattr_inode_update_fn(struct btree_trans *trans,
+				      struct bch_inode_info *inode,
+				      struct bch_inode_unpacked *bi,
+				      void *p)
+{
+	struct bch_fs *c = trans->c;
+	struct flags_set *s = p;
+
+	/*
+	 * We're relying on btree locking here for exclusion with other ioctl
+	 * calls - use the flags in the btree (@bi), not inode->i_flags:
+	 */
+	if (!S_ISREG(bi->bi_mode) &&
+	    !S_ISDIR(bi->bi_mode) &&
+	    (s->flags & (BCH_INODE_nodump|BCH_INODE_noatime)) != s->flags)
+		return -EINVAL;
+
+	if (s->casefold != bi->bi_casefold) {
+#ifdef CONFIG_UNICODE
+		int ret = 0;
+		/* Not supported on individual files. */
+		if (!S_ISDIR(bi->bi_mode))
+			return -EOPNOTSUPP;
+
+		/*
+		 * Make sure the dir is empty, as otherwise we'd need to
+		 * rehash everything and update the dirent keys.
+		 */
+		ret = bch2_empty_dir_trans(trans, inode_inum(inode));
+		if (ret < 0)
+			return ret;
+
+		ret = bch2_request_incompat_feature(c, bcachefs_metadata_version_casefolding);
+		if (ret)
+			return ret;
+
+		bch2_check_set_feature(c, BCH_FEATURE_casefolding);
+
+		bi->bi_casefold = s->casefold;
+		bi->bi_fields_set &= ~BIT(Inode_opt_casefold);
+		bi->bi_fields_set |= s->casefold << Inode_opt_casefold;
+
+#else
+		printk(KERN_ERR "Cannot use casefolding on a kernel without CONFIG_UNICODE\n");
+		return -EOPNOTSUPP;
+#endif
+	}
+
+	if (s->set_project) {
+		bi->bi_project = s->projid;
+		bi->bi_fields_set |= BIT(Inode_opt_project);
+	}
+
+	bi->bi_flags &= ~s->mask;
+	bi->bi_flags |= s->flags;
+
+	bi->bi_ctime = timespec_to_bch2_time(c, current_time(&inode->v));
+	return 0;
+}
+
+static int bch2_fileattr_set(struct mnt_idmap *idmap,
+			     struct dentry *dentry,
+			     struct fileattr *fa)
+{
+	struct bch_inode_info *inode = to_bch_ei(d_inode(dentry));
+	struct bch_fs *c = inode->v.i_sb->s_fs_info;
+	struct flags_set s = {};
+	int ret;
+
+	if (fa->fsx_valid) {
+		fa->fsx_xflags &= ~FS_XFLAG_PROJINHERIT;
+
+		s.mask = map_defined(bch_flags_to_xflags);
+		s.flags |= map_flags_rev(bch_flags_to_xflags, fa->fsx_xflags);
+		if (fa->fsx_xflags)
+			return -EOPNOTSUPP;
+
+		if (fa->fsx_projid >= U32_MAX)
+			return -EINVAL;
+
+		/*
+		 * inode fields accessible via the xattr interface are stored with a +1
+		 * bias, so that 0 means unset:
+		 */
+		if ((inode->ei_inode.bi_project ||
+		     fa->fsx_projid) &&
+		    inode->ei_inode.bi_project != fa->fsx_projid + 1) {
+			s.projid = fa->fsx_projid + 1;
+			s.set_project = true;
+		}
+	}
+
+	if (fa->flags_valid) {
+		s.mask = map_defined(bch_flags_to_uflags);
+
+		s.set_casefold = true;
+		s.casefold = (fa->flags & FS_CASEFOLD_FL) != 0;
+		fa->flags &= ~FS_CASEFOLD_FL;
+
+		s.flags |= map_flags_rev(bch_flags_to_uflags, fa->flags);
+		if (fa->flags)
+			return -EOPNOTSUPP;
+	}
+
+	mutex_lock(&inode->ei_update_lock);
+	ret   = bch2_subvol_is_ro(c, inode->ei_inum.subvol) ?:
+		(s.set_project
+		 ? bch2_set_projid(c, inode, fa->fsx_projid)
+		 : 0) ?:
+		bch2_write_inode(c, inode, fssetxattr_inode_update_fn, &s,
+			       ATTR_CTIME);
+	mutex_unlock(&inode->ei_update_lock);
+	return ret;
+}
+
 static const struct file_operations bch_file_operations = {
 	.open		= bch2_open,
 	.llseek		= bch2_llseek,
@@ -1475,6 +1651,8 @@ static const struct inode_operations bch_file_inode_operations = {
 	.get_inode_acl	= bch2_get_acl,
 	.set_acl	= bch2_set_acl,
 #endif
+	.fileattr_get	= bch2_fileattr_get,
+	.fileattr_set	= bch2_fileattr_set,
 };
 
 static const struct inode_operations bch_dir_inode_operations = {
@@ -1495,6 +1673,8 @@ static const struct inode_operations bch_dir_inode_operations = {
 	.get_inode_acl	= bch2_get_acl,
 	.set_acl	= bch2_set_acl,
 #endif
+	.fileattr_get	= bch2_fileattr_get,
+	.fileattr_set	= bch2_fileattr_set,
 };
 
 static const struct file_operations bch_dir_file_operations = {
@@ -1517,6 +1697,8 @@ static const struct inode_operations bch_symlink_inode_operations = {
 	.get_inode_acl	= bch2_get_acl,
 	.set_acl	= bch2_set_acl,
 #endif
+	.fileattr_get	= bch2_fileattr_get,
+	.fileattr_set	= bch2_fileattr_set,
 };
 
 static const struct inode_operations bch_special_inode_operations = {
@@ -1527,6 +1709,8 @@ static const struct inode_operations bch_special_inode_operations = {
 	.get_inode_acl	= bch2_get_acl,
 	.set_acl	= bch2_set_acl,
 #endif
+	.fileattr_get	= bch2_fileattr_get,
+	.fileattr_set	= bch2_fileattr_set,
 };
 
 static const struct address_space_operations bch_address_space_operations = {
@@ -2032,12 +2216,14 @@ static int bch2_show_devname(struct seq_file *seq, struct dentry *root)
 	struct bch_fs *c = root->d_sb->s_fs_info;
 	bool first = true;
 
-	for_each_online_member(c, ca) {
+	rcu_read_lock();
+	for_each_online_member_rcu(c, ca) {
 		if (!first)
 			seq_putc(seq, ':');
 		first = false;
 		seq_puts(seq, ca->disk_sb.sb_name);
 	}
+	rcu_read_unlock();
 
 	return 0;
 }
@@ -2235,15 +2421,16 @@ got_sb:
 
 	sb->s_bdi->ra_pages		= VM_READAHEAD_PAGES;
 
-	for_each_online_member(c, ca) {
+	rcu_read_lock();
+	for_each_online_member_rcu(c, ca) {
 		struct block_device *bdev = ca->disk_sb.bdev;
 
 		/* XXX: create an anonymous device for multi device filesystems */
 		sb->s_bdev	= bdev;
 		sb->s_dev	= bdev->bd_dev;
-		percpu_ref_put(&ca->io_ref[READ]);
 		break;
 	}
+	rcu_read_unlock();
 
 	c->dev = sb->s_dev;
 
diff --git a/libbcachefs/inode_format.h b/libbcachefs/inode_format.h
index 117110af..87e193e8 100644
--- a/libbcachefs/inode_format.h
+++ b/libbcachefs/inode_format.h
@@ -103,7 +103,8 @@ struct bch_inode_generation {
 	x(bi_parent_subvol,		32)	\
 	x(bi_nocow,			8)	\
 	x(bi_depth,			32)	\
-	x(bi_inodes_32bit,		8)
+	x(bi_inodes_32bit,		8)	\
+	x(bi_casefold,			8)
 
 /* subset of BCH_INODE_FIELDS */
 #define BCH_INODE_OPTS()			\
@@ -117,7 +118,8 @@ struct bch_inode_generation {
 	x(background_target,		16)	\
 	x(erasure_code,			16)	\
 	x(nocow,			8)	\
-	x(inodes_32bit,			8)
+	x(inodes_32bit,			8)	\
+	x(casefold,			8)
 
 enum inode_opt_id {
 #define x(name, ...)				\
@@ -137,8 +139,7 @@ enum inode_opt_id {
 	x(i_sectors_dirty,		6)	\
 	x(unlinked,			7)	\
 	x(backptr_untrusted,		8)	\
-	x(has_child_snapshot,		9)	\
-	x(casefolded,			10)
+	x(has_child_snapshot,		9)
 
 /* bits 20+ reserved for packed fields below: */
 
diff --git a/libbcachefs/io_read.c b/libbcachefs/io_read.c
index 9a2d5ac5..f23c3bfe 100644
--- a/libbcachefs/io_read.c
+++ b/libbcachefs/io_read.c
@@ -9,6 +9,7 @@
 #include "bcachefs.h"
 #include "alloc_background.h"
 #include "alloc_foreground.h"
+#include "async_objs.h"
 #include "btree_update.h"
 #include "buckets.h"
 #include "checksum.h"
@@ -17,6 +18,7 @@
 #include "data_update.h"
 #include "disk_groups.h"
 #include "ec.h"
+#include "enumerated_ref.h"
 #include "error.h"
 #include "io_read.h"
 #include "io_misc.h"
@@ -81,18 +83,6 @@ static bool bch2_target_congested(struct bch_fs *c, u16 target)
 
 /* Cache promotion on read */
 
-struct promote_op {
-	struct rcu_head		rcu;
-	u64			start_time;
-
-	struct rhash_head	hash;
-	struct bpos		pos;
-
-	struct work_struct	work;
-	struct data_update	write;
-	struct bio_vec		bi_inline_vecs[]; /* must be last */
-};
-
 static const struct rhashtable_params bch_promote_params = {
 	.head_offset		= offsetof(struct promote_op, hash),
 	.key_offset		= offsetof(struct promote_op, pos),
@@ -170,9 +160,11 @@ static noinline void promote_free(struct bch_read_bio *rbio)
 					 bch_promote_params);
 	BUG_ON(ret);
 
+	async_object_list_del(c, promote, op->list_idx);
+
 	bch2_data_update_exit(&op->write);
 
-	bch2_write_ref_put(c, BCH_WRITE_REF_promote);
+	enumerated_ref_put(&c->writes, BCH_WRITE_REF_promote);
 	kfree_rcu(op, rcu);
 }
 
@@ -237,7 +229,7 @@ static struct bch_read_bio *__promote_alloc(struct btree_trans *trans,
 			return NULL;
 	}
 
-	if (!bch2_write_ref_tryget(c, BCH_WRITE_REF_promote))
+	if (!enumerated_ref_tryget(&c->writes, BCH_WRITE_REF_promote))
 		return ERR_PTR(-BCH_ERR_nopromote_no_writes);
 
 	struct promote_op *op = kzalloc(sizeof(*op), GFP_KERNEL);
@@ -255,6 +247,10 @@ static struct bch_read_bio *__promote_alloc(struct btree_trans *trans,
 		goto err;
 	}
 
+	ret = async_object_list_add(c, promote, op, &op->list_idx);
+	if (ret < 0)
+		goto err_remove_hash;
+
 	ret = bch2_data_update_init(trans, NULL, NULL, &op->write,
 			writepoint_hashed((unsigned long) current),
 			&orig->opts,
@@ -266,7 +262,7 @@ static struct bch_read_bio *__promote_alloc(struct btree_trans *trans,
 	 * -BCH_ERR_ENOSPC_disk_reservation:
 	 */
 	if (ret)
-		goto err_remove_hash;
+		goto err_remove_list;
 
 	rbio_init_fragment(&op->write.rbio.bio, orig);
 	op->write.rbio.bounce	= true;
@@ -274,6 +270,8 @@ static struct bch_read_bio *__promote_alloc(struct btree_trans *trans,
 	op->write.op.end_io = promote_done;
 
 	return &op->write.rbio;
+err_remove_list:
+	async_object_list_del(c, promote, op->list_idx);
 err_remove_hash:
 	BUG_ON(rhashtable_remove_fast(&c->promote_table, &op->hash,
 				      bch_promote_params));
@@ -282,7 +280,7 @@ err:
 	/* We may have added to the rhashtable and thus need rcu freeing: */
 	kfree_rcu(op, rcu);
 err_put:
-	bch2_write_ref_put(c, BCH_WRITE_REF_promote);
+	enumerated_ref_put(&c->writes, BCH_WRITE_REF_promote);
 	return ERR_PTR(ret);
 }
 
@@ -346,6 +344,18 @@ nopromote:
 	return NULL;
 }
 
+void bch2_promote_op_to_text(struct printbuf *out, struct promote_op *op)
+{
+	if (!op->write.read_done) {
+		prt_printf(out, "parent read: %px\n", op->write.rbio.parent);
+		printbuf_indent_add(out, 2);
+		bch2_read_bio_to_text(out, op->write.rbio.parent);
+		printbuf_indent_sub(out, 2);
+	}
+
+	bch2_data_update_to_text(out, &op->write);
+}
+
 /* Read */
 
 static int bch2_read_err_msg_trans(struct btree_trans *trans, struct printbuf *out,
@@ -402,7 +412,7 @@ static inline struct bch_read_bio *bch2_rbio_free(struct bch_read_bio *rbio)
 
 	if (rbio->have_ioref) {
 		struct bch_dev *ca = bch2_dev_have_ref(rbio->c, rbio->pick.ptr.dev);
-		percpu_ref_put(&ca->io_ref[READ]);
+		enumerated_ref_put(&ca->io_ref[READ], BCH_DEV_READ_REF_io_read);
 	}
 
 	if (rbio->split) {
@@ -414,6 +424,8 @@ static inline struct bch_read_bio *bch2_rbio_free(struct bch_read_bio *rbio)
 			else
 				promote_free(rbio);
 		} else {
+			async_object_list_del(rbio->c, rbio, rbio->list_idx);
+
 			if (rbio->bounce)
 				bch2_bio_free_pages_pool(rbio->c, &rbio->bio);
 
@@ -1090,7 +1102,8 @@ retry_pick:
 		goto err;
 	}
 
-	struct bch_dev *ca = bch2_dev_get_ioref(c, pick.ptr.dev, READ);
+	struct bch_dev *ca = bch2_dev_get_ioref(c, pick.ptr.dev, READ,
+					BCH_DEV_READ_REF_io_read);
 
 	/*
 	 * Stale dirty pointers are treated as IO errors, but @failed isn't
@@ -1104,7 +1117,7 @@ retry_pick:
 	    unlikely(dev_ptr_stale(ca, &pick.ptr))) {
 		read_from_stale_dirty_pointer(trans, ca, k, pick.ptr);
 		bch2_mark_io_failure(failed, &pick, false);
-		percpu_ref_put(&ca->io_ref[READ]);
+		enumerated_ref_put(&ca->io_ref[READ], BCH_DEV_READ_REF_io_read);
 		goto retry_pick;
 	}
 
@@ -1137,7 +1150,8 @@ retry_pick:
 		 */
 		if (pick.crc.compressed_size > u->op.wbio.bio.bi_iter.bi_size) {
 			if (ca)
-				percpu_ref_put(&ca->io_ref[READ]);
+				enumerated_ref_put(&ca->io_ref[READ],
+					BCH_DEV_READ_REF_io_read);
 			rbio->ret = -BCH_ERR_data_read_buffer_too_small;
 			goto out_read_done;
 		}
@@ -1191,6 +1205,8 @@ retry_pick:
 
 		bch2_bio_alloc_pages_pool(c, &rbio->bio, sectors << 9);
 		rbio->bounce	= true;
+
+		async_object_list_add(c, rbio, rbio, &rbio->list_idx);
 	} else if (flags & BCH_READ_must_clone) {
 		/*
 		 * Have to clone if there were any splits, due to error
@@ -1204,6 +1220,8 @@ retry_pick:
 						 &c->bio_read_split),
 				 orig);
 		rbio->bio.bi_iter = iter;
+
+		async_object_list_add(c, rbio, rbio, &rbio->list_idx);
 	} else {
 		rbio = orig;
 		rbio->bio.bi_iter = iter;
@@ -1479,6 +1497,41 @@ err:
 	return ret;
 }
 
+static const char * const bch2_read_bio_flags[] = {
+#define x(n)	#n,
+	BCH_READ_FLAGS()
+#undef x
+	NULL
+};
+
+void bch2_read_bio_to_text(struct printbuf *out, struct bch_read_bio *rbio)
+{
+	u64 now = local_clock();
+	prt_printf(out, "start_time:\t%llu\n", rbio->start_time ? now - rbio->start_time : 0);
+	prt_printf(out, "submit_time:\t%llu\n", rbio->submit_time ? now - rbio->submit_time : 0);
+
+	if (!rbio->split)
+		prt_printf(out, "end_io:\t%ps\n", rbio->end_io);
+	else
+		prt_printf(out, "parent:\t%px\n", rbio->parent);
+
+	prt_printf(out, "bi_end_io:\t%ps\n", rbio->bio.bi_end_io);
+
+	prt_printf(out, "promote:\t%u\n",	rbio->promote);
+	prt_printf(out, "bounce:\t%u\n",	rbio->bounce);
+	prt_printf(out, "split:\t%u\n",		rbio->split);
+	prt_printf(out, "have_ioref:\t%u\n",	rbio->have_ioref);
+	prt_printf(out, "narrow_crcs:\t%u\n",	rbio->narrow_crcs);
+	prt_printf(out, "context:\t%u\n",	rbio->context);
+	prt_printf(out, "ret:\t%s\n",		bch2_err_str(rbio->ret));
+
+	prt_printf(out, "flags:\t");
+	bch2_prt_bitflags(out, bch2_read_bio_flags, rbio->flags);
+	prt_newline(out);
+
+	bch2_bio_to_text(out, &rbio->bio);
+}
+
 void bch2_fs_io_read_exit(struct bch_fs *c)
 {
 	if (c->promote_table.tbl)
diff --git a/libbcachefs/io_read.h b/libbcachefs/io_read.h
index 1a85b092..c08b9c04 100644
--- a/libbcachefs/io_read.h
+++ b/libbcachefs/io_read.h
@@ -4,6 +4,7 @@
 
 #include "bkey_buf.h"
 #include "btree_iter.h"
+#include "extents_types.h"
 #include "reflink.h"
 
 struct bch_read_bio {
@@ -48,6 +49,9 @@ struct bch_read_bio {
 	u16			_state;
 	};
 	s16			ret;
+#ifdef CONFIG_BCACHEFS_ASYNC_OBJECT_LISTS
+	unsigned		list_idx;
+#endif
 
 	struct extent_ptr_decoded pick;
 
@@ -173,6 +177,9 @@ static inline struct bch_read_bio *rbio_init_fragment(struct bio *bio,
 	rbio->split		= true;
 	rbio->parent		= orig;
 	rbio->opts		= orig->opts;
+#ifdef CONFIG_BCACHEFS_ASYNC_OBJECT_LISTS
+	rbio->list_idx	= 0;
+#endif
 	return rbio;
 }
 
@@ -190,9 +197,16 @@ static inline struct bch_read_bio *rbio_init(struct bio *bio,
 	rbio->ret		= 0;
 	rbio->opts		= opts;
 	rbio->bio.bi_end_io	= end_io;
+#ifdef CONFIG_BCACHEFS_ASYNC_OBJECT_LISTS
+	rbio->list_idx	= 0;
+#endif
 	return rbio;
 }
 
+struct promote_op;
+void bch2_promote_op_to_text(struct printbuf *, struct promote_op *);
+void bch2_read_bio_to_text(struct printbuf *, struct bch_read_bio *);
+
 void bch2_fs_io_read_exit(struct bch_fs *);
 int bch2_fs_io_read_init(struct bch_fs *);
 
diff --git a/libbcachefs/io_write.c b/libbcachefs/io_write.c
index 4dabff3a..f7c5fcbf 100644
--- a/libbcachefs/io_write.c
+++ b/libbcachefs/io_write.c
@@ -15,6 +15,7 @@
 #include "compress.h"
 #include "debug.h"
 #include "ec.h"
+#include "enumerated_ref.h"
 #include "error.h"
 #include "extent_update.h"
 #include "inode.h"
@@ -441,6 +442,10 @@ void bch2_submit_wbio_replicas(struct bch_write_bio *wbio, struct bch_fs *c,
 {
 	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(bkey_i_to_s_c(k));
 	struct bch_write_bio *n;
+	unsigned ref_rw  = type == BCH_DATA_btree ? READ : WRITE;
+	unsigned ref_idx = type == BCH_DATA_btree
+		? BCH_DEV_READ_REF_btree_node_write
+		: BCH_DEV_WRITE_REF_io_write;
 
 	BUG_ON(c->opts.nochanges);
 
@@ -452,7 +457,7 @@ void bch2_submit_wbio_replicas(struct bch_write_bio *wbio, struct bch_fs *c,
 		 */
 		struct bch_dev *ca = nocow
 			? bch2_dev_have_ref(c, ptr->dev)
-			: bch2_dev_get_ioref(c, ptr->dev, type == BCH_DATA_btree ? READ : WRITE);
+			: bch2_dev_get_ioref(c, ptr->dev, ref_rw, ref_idx);
 
 		if (to_entry(ptr + 1) < ptrs.end) {
 			n = to_wbio(bio_alloc_clone(NULL, &wbio->bio, GFP_NOFS, &c->replica_set));
@@ -512,7 +517,7 @@ static void bch2_write_done(struct closure *cl)
 	bch2_disk_reservation_put(c, &op->res);
 
 	if (!(op->flags & BCH_WRITE_move))
-		bch2_write_ref_put(c, BCH_WRITE_REF_write);
+		enumerated_ref_put(&c->writes, BCH_WRITE_REF_write);
 	bch2_keylist_free(&op->insert_keys, op->inline_keys);
 
 	EBUG_ON(cl->parent);
@@ -727,7 +732,8 @@ static void bch2_write_endio(struct bio *bio)
 	}
 
 	if (wbio->have_ioref)
-		percpu_ref_put(&ca->io_ref[WRITE]);
+		enumerated_ref_put(&ca->io_ref[WRITE],
+				   BCH_DEV_WRITE_REF_io_write);
 
 	if (wbio->bounce)
 		bch2_bio_free_pages_pool(c, bio);
@@ -1324,7 +1330,8 @@ retry:
 		/* Get iorefs before dropping btree locks: */
 		struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
 		bkey_for_each_ptr(ptrs, ptr) {
-			struct bch_dev *ca = bch2_dev_get_ioref(c, ptr->dev, WRITE);
+			struct bch_dev *ca = bch2_dev_get_ioref(c, ptr->dev, WRITE,
+							BCH_DEV_WRITE_REF_io_write);
 			if (unlikely(!ca))
 				goto err_get_ioref;
 
@@ -1426,7 +1433,8 @@ err:
 	return;
 err_get_ioref:
 	darray_for_each(buckets, i)
-		percpu_ref_put(&bch2_dev_have_ref(c, i->b.inode)->io_ref[WRITE]);
+		enumerated_ref_put(&bch2_dev_have_ref(c, i->b.inode)->io_ref[WRITE],
+				   BCH_DEV_WRITE_REF_io_write);
 
 	/* Fall back to COW path: */
 	goto out;
@@ -1660,7 +1668,7 @@ CLOSURE_CALLBACK(bch2_write)
 	}
 
 	if (!(op->flags & BCH_WRITE_move) &&
-	    !bch2_write_ref_tryget(c, BCH_WRITE_REF_write)) {
+	    !enumerated_ref_tryget(&c->writes, BCH_WRITE_REF_write)) {
 		op->error = -BCH_ERR_erofs_no_writes;
 		goto err;
 	}
diff --git a/libbcachefs/journal.c b/libbcachefs/journal.c
index 3694b83a..f2963a6c 100644
--- a/libbcachefs/journal.c
+++ b/libbcachefs/journal.c
@@ -12,6 +12,7 @@
 #include "btree_update.h"
 #include "btree_write_buffer.h"
 #include "buckets.h"
+#include "enumerated_ref.h"
 #include "error.h"
 #include "journal.h"
 #include "journal_io.h"
@@ -699,8 +700,10 @@ static unsigned max_dev_latency(struct bch_fs *c)
 {
 	u64 nsecs = 0;
 
-	for_each_rw_member(c, ca)
+	rcu_read_lock();
+	for_each_rw_member_rcu(c, ca)
 		nsecs = max(nsecs, ca->io_latency[WRITE].stats.max_duration);
+	rcu_read_unlock();
 
 	return nsecs_to_jiffies(nsecs);
 }
@@ -987,11 +990,11 @@ int bch2_journal_meta(struct journal *j)
 {
 	struct bch_fs *c = container_of(j, struct bch_fs, journal);
 
-	if (!bch2_write_ref_tryget(c, BCH_WRITE_REF_journal))
+	if (!enumerated_ref_tryget(&c->writes, BCH_WRITE_REF_journal))
 		return -BCH_ERR_erofs_no_writes;
 
 	int ret = __bch2_journal_meta(j);
-	bch2_write_ref_put(c, BCH_WRITE_REF_journal);
+	enumerated_ref_put(&c->writes, BCH_WRITE_REF_journal);
 	return ret;
 }
 
@@ -1333,13 +1336,14 @@ err:
 
 int bch2_fs_journal_alloc(struct bch_fs *c)
 {
-	for_each_online_member(c, ca) {
+	for_each_online_member(c, ca, BCH_DEV_READ_REF_fs_journal_alloc) {
 		if (ca->journal.nr)
 			continue;
 
 		int ret = bch2_dev_journal_alloc(ca, true);
 		if (ret) {
-			percpu_ref_put(&ca->io_ref[READ]);
+			enumerated_ref_put(&ca->io_ref[READ],
+					   BCH_DEV_READ_REF_fs_journal_alloc);
 			return ret;
 		}
 	}
diff --git a/libbcachefs/journal_io.c b/libbcachefs/journal_io.c
index 913125df..58e3983d 100644
--- a/libbcachefs/journal_io.c
+++ b/libbcachefs/journal_io.c
@@ -1218,7 +1218,7 @@ static CLOSURE_CALLBACK(bch2_journal_read_device)
 out:
 	bch_verbose(c, "journal read done on device %s, ret %i", ca->name, ret);
 	kvfree(buf.data);
-	percpu_ref_put(&ca->io_ref[READ]);
+	enumerated_ref_put(&ca->io_ref[READ], BCH_DEV_READ_REF_journal_read);
 	closure_return(cl);
 	return;
 err:
@@ -1253,7 +1253,8 @@ int bch2_journal_read(struct bch_fs *c,
 
 		if ((ca->mi.state == BCH_MEMBER_STATE_rw ||
 		     ca->mi.state == BCH_MEMBER_STATE_ro) &&
-		    percpu_ref_tryget(&ca->io_ref[READ]))
+		    enumerated_ref_tryget(&ca->io_ref[READ],
+					  BCH_DEV_READ_REF_journal_read))
 			closure_call(&ca->journal.read,
 				     bch2_journal_read_device,
 				     system_unbound_wq,
@@ -1768,7 +1769,7 @@ static void journal_write_endio(struct bio *bio)
 	}
 
 	closure_put(&w->io);
-	percpu_ref_put(&ca->io_ref[WRITE]);
+	enumerated_ref_put(&ca->io_ref[WRITE], BCH_DEV_WRITE_REF_journal_write);
 }
 
 static CLOSURE_CALLBACK(journal_write_submit)
@@ -1779,7 +1780,8 @@ static CLOSURE_CALLBACK(journal_write_submit)
 	unsigned sectors = vstruct_sectors(w->data, c->block_bits);
 
 	extent_for_each_ptr(bkey_i_to_s_extent(&w->key), ptr) {
-		struct bch_dev *ca = bch2_dev_get_ioref(c, ptr->dev, WRITE);
+		struct bch_dev *ca = bch2_dev_get_ioref(c, ptr->dev, WRITE,
+					BCH_DEV_WRITE_REF_journal_write);
 		if (!ca) {
 			/* XXX: fix this */
 			bch_err(c, "missing device for journal write\n");
@@ -1842,8 +1844,9 @@ static CLOSURE_CALLBACK(journal_write_preflush)
 	}
 
 	if (w->separate_flush) {
-		for_each_rw_member(c, ca) {
-			percpu_ref_get(&ca->io_ref[WRITE]);
+		for_each_rw_member(c, ca, BCH_DEV_WRITE_REF_journal_write) {
+			enumerated_ref_get(&ca->io_ref[WRITE],
+					   BCH_DEV_WRITE_REF_journal_write);
 
 			struct journal_device *ja = &ca->journal;
 			struct bio *bio = &ja->bio[w->idx]->bio;
@@ -2053,12 +2056,9 @@ CLOSURE_CALLBACK(bch2_journal_write)
 	struct journal *j = container_of(w, struct journal, buf[w->idx]);
 	struct bch_fs *c = container_of(j, struct bch_fs, journal);
 	struct bch_replicas_padded replicas;
-	unsigned nr_rw_members = 0;
+	unsigned nr_rw_members = dev_mask_nr(&c->rw_devs[BCH_DATA_journal]);
 	int ret;
 
-	for_each_rw_member(c, ca)
-		nr_rw_members++;
-
 	BUG_ON(BCH_SB_CLEAN(c->disk_sb.sb));
 	BUG_ON(!w->write_started);
 	BUG_ON(w->write_allocated);
diff --git a/libbcachefs/journal_reclaim.c b/libbcachefs/journal_reclaim.c
index d1c0fc59..66bfb95f 100644
--- a/libbcachefs/journal_reclaim.c
+++ b/libbcachefs/journal_reclaim.c
@@ -285,7 +285,7 @@ void bch2_journal_do_discards(struct journal *j)
 
 	mutex_lock(&j->discard_lock);
 
-	for_each_rw_member(c, ca) {
+	for_each_rw_member(c, ca, BCH_DEV_WRITE_REF_journal_do_discards) {
 		struct journal_device *ja = &ca->journal;
 
 		while (should_discard_bucket(j, ja)) {
@@ -617,7 +617,8 @@ static u64 journal_seq_to_flush(struct journal *j)
 
 	spin_lock(&j->lock);
 
-	for_each_rw_member(c, ca) {
+	rcu_read_lock();
+	for_each_rw_member_rcu(c, ca) {
 		struct journal_device *ja = &ca->journal;
 		unsigned nr_buckets, bucket_to_flush;
 
@@ -631,6 +632,7 @@ static u64 journal_seq_to_flush(struct journal *j)
 		seq_to_flush = max(seq_to_flush,
 				   ja->bucket_seq[bucket_to_flush]);
 	}
+	rcu_read_unlock();
 
 	/* Also flush if the pin fifo is more than half full */
 	seq_to_flush = max_t(s64, seq_to_flush,
diff --git a/libbcachefs/movinggc.c b/libbcachefs/movinggc.c
index 159410c5..e97e87eb 100644
--- a/libbcachefs/movinggc.c
+++ b/libbcachefs/movinggc.c
@@ -279,7 +279,8 @@ unsigned long bch2_copygc_wait_amount(struct bch_fs *c)
 {
 	s64 wait = S64_MAX, fragmented_allowed, fragmented;
 
-	for_each_rw_member(c, ca) {
+	rcu_read_lock();
+	for_each_rw_member_rcu(c, ca) {
 		struct bch_dev_usage_full usage_full = bch2_dev_usage_full_read(ca);
 		struct bch_dev_usage usage;
 
@@ -296,6 +297,7 @@ unsigned long bch2_copygc_wait_amount(struct bch_fs *c)
 
 		wait = min(wait, max(0LL, fragmented_allowed - fragmented));
 	}
+	rcu_read_unlock();
 
 	return wait;
 }
@@ -356,6 +358,13 @@ static int bch2_copygc_thread(void *arg)
 
 	set_freezable();
 
+	/*
+	 * Data move operations can't run until after check_snapshots has
+	 * completed, and bch2_snapshot_is_ancestor() is available.
+	 */
+	kthread_wait_freezable(c->recovery_pass_done > BCH_RECOVERY_PASS_check_snapshots ||
+			       kthread_should_stop());
+
 	bch2_move_stats_init(&move_stats, "copygc");
 	bch2_moving_ctxt_init(&ctxt, c, NULL, &move_stats,
 			      writepoint_ptr(&c->copygc_write_point),
diff --git a/libbcachefs/namei.c b/libbcachefs/namei.c
index 0d65ea96..46f3c8b1 100644
--- a/libbcachefs/namei.c
+++ b/libbcachefs/namei.c
@@ -47,10 +47,6 @@ int bch2_create_trans(struct btree_trans *trans,
 	if (ret)
 		goto err;
 
-	/* Inherit casefold state from parent. */
-	if (S_ISDIR(mode))
-		new_inode->bi_flags |= dir_u->bi_flags & BCH_INODE_casefolded;
-
 	if (!(flags & BCH_CREATE_SNAPSHOT)) {
 		/* Normal create path - allocate a new inode: */
 		bch2_inode_init_late(new_inode, now, uid, gid, mode, rdev, dir_u);
diff --git a/libbcachefs/opts.h b/libbcachefs/opts.h
index 5cdb1880..b8cd0b04 100644
--- a/libbcachefs/opts.h
+++ b/libbcachefs/opts.h
@@ -229,6 +229,11 @@ enum fsck_err_opts {
 	  OPT_BOOL(),							\
 	  BCH_SB_ERASURE_CODE,		false,				\
 	  NULL,		"Enable erasure coding (DO NOT USE YET)")	\
+	x(casefold,			u8,				\
+	  OPT_FS|OPT_INODE|OPT_FORMAT,					\
+	  OPT_BOOL(),							\
+	  BCH_SB_CASEFOLD,		false,				\
+	  NULL,		"Dirent lookups are casefolded")		\
 	x(inodes_32bit,			u8,				\
 	  OPT_FS|OPT_INODE|OPT_FORMAT|OPT_MOUNT|OPT_RUNTIME,		\
 	  OPT_BOOL(),							\
diff --git a/libbcachefs/rebalance.c b/libbcachefs/rebalance.c
index b0314674..a81ffff4 100644
--- a/libbcachefs/rebalance.c
+++ b/libbcachefs/rebalance.c
@@ -587,6 +587,13 @@ static int bch2_rebalance_thread(void *arg)
 
 	set_freezable();
 
+	/*
+	 * Data move operations can't run until after check_snapshots has
+	 * completed, and bch2_snapshot_is_ancestor() is available.
+	 */
+	kthread_wait_freezable(c->recovery_pass_done > BCH_RECOVERY_PASS_check_snapshots ||
+			       kthread_should_stop());
+
 	bch2_moving_ctxt_init(&ctxt, c, NULL, &r->work_stats,
 			      writepoint_ptr(&c->rebalance_write_point),
 			      true);
diff --git a/libbcachefs/recovery.c b/libbcachefs/recovery.c
index df953b64..e36fcab9 100644
--- a/libbcachefs/recovery.c
+++ b/libbcachefs/recovery.c
@@ -18,6 +18,7 @@
 #include "journal_seq_blacklist.h"
 #include "logged_ops.h"
 #include "move.h"
+#include "movinggc.h"
 #include "namei.h"
 #include "quota.h"
 #include "rebalance.h"
@@ -1214,6 +1215,9 @@ int bch2_fs_initialize(struct bch_fs *c)
 
 	c->recovery_pass_done = BCH_RECOVERY_PASS_NR - 1;
 
+	bch2_copygc_wakeup(c);
+	bch2_rebalance_wakeup(c);
+
 	if (enabled_qtypes(c)) {
 		ret = bch2_fs_quota_read(c);
 		if (ret)
diff --git a/libbcachefs/recovery_passes.c b/libbcachefs/recovery_passes.c
index 7a644408..87150dd3 100644
--- a/libbcachefs/recovery_passes.c
+++ b/libbcachefs/recovery_passes.c
@@ -12,6 +12,7 @@
 #include "journal.h"
 #include "lru.h"
 #include "logged_ops.h"
+#include "movinggc.h"
 #include "rebalance.h"
 #include "recovery.h"
 #include "recovery_passes.h"
@@ -311,49 +312,52 @@ int bch2_run_recovery_passes(struct bch_fs *c)
 	 */
 	c->opts.recovery_passes_exclude &= ~BCH_RECOVERY_PASS_set_may_go_rw;
 
-	while (c->curr_recovery_pass < ARRAY_SIZE(recovery_pass_fns) && !ret) {
-		c->next_recovery_pass = c->curr_recovery_pass + 1;
+	spin_lock_irq(&c->recovery_pass_lock);
 
-		spin_lock_irq(&c->recovery_pass_lock);
+	while (c->curr_recovery_pass < ARRAY_SIZE(recovery_pass_fns) && !ret) {
+		unsigned prev_done = c->recovery_pass_done;
 		unsigned pass = c->curr_recovery_pass;
 
+		c->next_recovery_pass = pass + 1;
+
 		if (c->opts.recovery_pass_last &&
-		    c->curr_recovery_pass > c->opts.recovery_pass_last) {
-			spin_unlock_irq(&c->recovery_pass_lock);
+		    c->curr_recovery_pass > c->opts.recovery_pass_last)
 			break;
-		}
 
-		if (!should_run_recovery_pass(c, pass)) {
-			c->curr_recovery_pass++;
-			c->recovery_pass_done = max(c->recovery_pass_done, pass);
+		if (should_run_recovery_pass(c, pass)) {
 			spin_unlock_irq(&c->recovery_pass_lock);
-			continue;
-		}
-		spin_unlock_irq(&c->recovery_pass_lock);
-
-		ret =   bch2_run_recovery_pass(c, pass) ?:
-			bch2_journal_flush(&c->journal);
-
-		if (!ret && !test_bit(BCH_FS_error, &c->flags))
-			bch2_clear_recovery_pass_required(c, pass);
-
-		spin_lock_irq(&c->recovery_pass_lock);
-		if (c->next_recovery_pass < c->curr_recovery_pass) {
-			/*
-			 * bch2_run_explicit_recovery_pass() was called: we
-			 * can't always catch -BCH_ERR_restart_recovery because
-			 * it may have been called from another thread (btree
-			 * node read completion)
-			 */
-			ret = 0;
-			c->recovery_passes_complete &= ~(~0ULL << c->curr_recovery_pass);
-		} else {
-			c->recovery_passes_complete |= BIT_ULL(pass);
-			c->recovery_pass_done = max(c->recovery_pass_done, pass);
+			ret =   bch2_run_recovery_pass(c, pass) ?:
+				bch2_journal_flush(&c->journal);
+
+			if (!ret && !test_bit(BCH_FS_error, &c->flags))
+				bch2_clear_recovery_pass_required(c, pass);
+			spin_lock_irq(&c->recovery_pass_lock);
+
+			if (c->next_recovery_pass < c->curr_recovery_pass) {
+				/*
+				 * bch2_run_explicit_recovery_pass() was called: we
+				 * can't always catch -BCH_ERR_restart_recovery because
+				 * it may have been called from another thread (btree
+				 * node read completion)
+				 */
+				ret = 0;
+				c->recovery_passes_complete &= ~(~0ULL << c->curr_recovery_pass);
+			} else {
+				c->recovery_passes_complete |= BIT_ULL(pass);
+				c->recovery_pass_done = max(c->recovery_pass_done, pass);
+			}
 		}
+
 		c->curr_recovery_pass = c->next_recovery_pass;
-		spin_unlock_irq(&c->recovery_pass_lock);
+
+		if (prev_done <= BCH_RECOVERY_PASS_check_snapshots &&
+		    c->recovery_pass_done > BCH_RECOVERY_PASS_check_snapshots) {
+			bch2_copygc_wakeup(c);
+			bch2_rebalance_wakeup(c);
+		}
 	}
 
+	spin_unlock_irq(&c->recovery_pass_lock);
+
 	return ret;
 }
diff --git a/libbcachefs/reflink.c b/libbcachefs/reflink.c
index 710178e3..3a13dbca 100644
--- a/libbcachefs/reflink.c
+++ b/libbcachefs/reflink.c
@@ -3,6 +3,7 @@
 #include "bkey_buf.h"
 #include "btree_update.h"
 #include "buckets.h"
+#include "enumerated_ref.h"
 #include "error.h"
 #include "extents.h"
 #include "inode.h"
@@ -610,7 +611,7 @@ s64 bch2_remap_range(struct bch_fs *c,
 		!bch2_request_incompat_feature(c, bcachefs_metadata_version_reflink_p_may_update_opts);
 	int ret = 0, ret2 = 0;
 
-	if (!bch2_write_ref_tryget(c, BCH_WRITE_REF_reflink))
+	if (!enumerated_ref_tryget(&c->writes, BCH_WRITE_REF_reflink))
 		return -BCH_ERR_erofs_no_writes;
 
 	bch2_check_set_feature(c, BCH_FEATURE_reflink);
@@ -761,7 +762,7 @@ err:
 	bch2_bkey_buf_exit(&new_src, c);
 	bch2_bkey_buf_exit(&new_dst, c);
 
-	bch2_write_ref_put(c, BCH_WRITE_REF_reflink);
+	enumerated_ref_put(&c->writes, BCH_WRITE_REF_reflink);
 
 	return dst_done ?: ret ?: ret2;
 }
diff --git a/libbcachefs/sb-members.h b/libbcachefs/sb-members.h
index e2a8d03a..0337e34d 100644
--- a/libbcachefs/sb-members.h
+++ b/libbcachefs/sb-members.h
@@ -4,6 +4,7 @@
 
 #include "darray.h"
 #include "bkey_types.h"
+#include "enumerated_ref.h"
 
 extern char * const bch2_member_error_strs[];
 
@@ -20,7 +21,7 @@ struct bch_member bch2_sb_member_get(struct bch_sb *sb, int i);
 
 static inline bool bch2_dev_is_online(struct bch_dev *ca)
 {
-	return !percpu_ref_is_zero(&ca->io_ref[READ]);
+	return !enumerated_ref_is_zero(&ca->io_ref[READ]);
 }
 
 static inline struct bch_dev *bch2_dev_rcu(struct bch_fs *, unsigned);
@@ -104,6 +105,12 @@ static inline struct bch_dev *__bch2_next_dev(struct bch_fs *c, struct bch_dev *
 	for (struct bch_dev *_ca = NULL;				\
 	     (_ca = __bch2_next_dev((_c), _ca, (_mask)));)
 
+#define for_each_online_member_rcu(_c, _ca)				\
+	for_each_member_device_rcu(_c, _ca, &(_c)->online_devs)
+
+#define for_each_rw_member_rcu(_c, _ca)					\
+	for_each_member_device_rcu(_c, _ca, &(_c)->rw_devs[BCH_DATA_free])
+
 static inline void bch2_dev_get(struct bch_dev *ca)
 {
 #ifdef CONFIG_BCACHEFS_DEBUG
@@ -157,33 +164,33 @@ static inline struct bch_dev *bch2_get_next_dev(struct bch_fs *c, struct bch_dev
 static inline struct bch_dev *bch2_get_next_online_dev(struct bch_fs *c,
 						       struct bch_dev *ca,
 						       unsigned state_mask,
-						       int rw)
+						       int rw, unsigned ref_idx)
 {
 	rcu_read_lock();
 	if (ca)
-		percpu_ref_put(&ca->io_ref[rw]);
+		enumerated_ref_put(&ca->io_ref[rw], ref_idx);
 
 	while ((ca = __bch2_next_dev(c, ca, NULL)) &&
 	       (!((1 << ca->mi.state) & state_mask) ||
-		!percpu_ref_tryget(&ca->io_ref[rw])))
+		!enumerated_ref_tryget(&ca->io_ref[rw], ref_idx)))
 		;
 	rcu_read_unlock();
 
 	return ca;
 }
 
-#define __for_each_online_member(_c, _ca, state_mask, rw)		\
+#define __for_each_online_member(_c, _ca, state_mask, rw, ref_idx)	\
 	for (struct bch_dev *_ca = NULL;				\
-	     (_ca = bch2_get_next_online_dev(_c, _ca, state_mask, rw));)
+	     (_ca = bch2_get_next_online_dev(_c, _ca, state_mask, rw, ref_idx));)
 
-#define for_each_online_member(c, ca)					\
-	__for_each_online_member(c, ca, ~0, READ)
+#define for_each_online_member(c, ca, ref_idx)				\
+	__for_each_online_member(c, ca, ~0, READ, ref_idx)
 
-#define for_each_rw_member(c, ca)					\
-	__for_each_online_member(c, ca, BIT(BCH_MEMBER_STATE_rw), WRITE)
+#define for_each_rw_member(c, ca, ref_idx)					\
+	__for_each_online_member(c, ca, BIT(BCH_MEMBER_STATE_rw), WRITE, ref_idx)
 
-#define for_each_readable_member(c, ca)				\
-	__for_each_online_member(c, ca,	BIT( BCH_MEMBER_STATE_rw)|BIT(BCH_MEMBER_STATE_ro), READ)
+#define for_each_readable_member(c, ca, ref_idx)				\
+	__for_each_online_member(c, ca,	BIT( BCH_MEMBER_STATE_rw)|BIT(BCH_MEMBER_STATE_ro), READ, ref_idx)
 
 static inline bool bch2_dev_exists(const struct bch_fs *c, unsigned dev)
 {
@@ -284,13 +291,14 @@ static inline struct bch_dev *bch2_dev_iterate(struct bch_fs *c, struct bch_dev
 	return bch2_dev_tryget(c, dev_idx);
 }
 
-static inline struct bch_dev *bch2_dev_get_ioref(struct bch_fs *c, unsigned dev, int rw)
+static inline struct bch_dev *bch2_dev_get_ioref(struct bch_fs *c, unsigned dev,
+						 int rw, unsigned ref_idx)
 {
 	might_sleep();
 
 	rcu_read_lock();
 	struct bch_dev *ca = bch2_dev_rcu(c, dev);
-	if (ca && !percpu_ref_tryget(&ca->io_ref[rw]))
+	if (ca && !enumerated_ref_tryget(&ca->io_ref[rw], ref_idx))
 		ca = NULL;
 	rcu_read_unlock();
 
@@ -300,21 +308,10 @@ static inline struct bch_dev *bch2_dev_get_ioref(struct bch_fs *c, unsigned dev,
 		return ca;
 
 	if (ca)
-		percpu_ref_put(&ca->io_ref[rw]);
+		enumerated_ref_put(&ca->io_ref[rw], ref_idx);
 	return NULL;
 }
 
-/* XXX kill, move to struct bch_fs */
-static inline struct bch_devs_mask bch2_online_devs(struct bch_fs *c)
-{
-	struct bch_devs_mask devs;
-
-	memset(&devs, 0, sizeof(devs));
-	for_each_online_member(c, ca)
-		__set_bit(ca->dev_idx, devs.d);
-	return devs;
-}
-
 extern const struct bch_sb_field_ops bch_sb_field_ops_members_v1;
 extern const struct bch_sb_field_ops bch_sb_field_ops_members_v2;
 
diff --git a/libbcachefs/snapshot.c b/libbcachefs/snapshot.c
index 2eede851..14ea09cc 100644
--- a/libbcachefs/snapshot.c
+++ b/libbcachefs/snapshot.c
@@ -6,6 +6,7 @@
 #include "btree_key_cache.h"
 #include "btree_update.h"
 #include "buckets.h"
+#include "enumerated_ref.h"
 #include "errcode.h"
 #include "error.h"
 #include "fs.h"
@@ -1661,18 +1662,18 @@ void bch2_delete_dead_snapshots_work(struct work_struct *work)
 	set_worker_desc("bcachefs-delete-dead-snapshots/%s", c->name);
 
 	bch2_delete_dead_snapshots(c);
-	bch2_write_ref_put(c, BCH_WRITE_REF_delete_dead_snapshots);
+	enumerated_ref_put(&c->writes, BCH_WRITE_REF_delete_dead_snapshots);
 }
 
 void bch2_delete_dead_snapshots_async(struct bch_fs *c)
 {
-	if (!bch2_write_ref_tryget(c, BCH_WRITE_REF_delete_dead_snapshots))
+	if (!enumerated_ref_tryget(&c->writes, BCH_WRITE_REF_delete_dead_snapshots))
 		return;
 
 	BUG_ON(!test_bit(BCH_FS_may_go_rw, &c->flags));
 
 	if (!queue_work(c->write_ref_wq, &c->snapshot_delete_work))
-		bch2_write_ref_put(c, BCH_WRITE_REF_delete_dead_snapshots);
+		enumerated_ref_put(&c->writes, BCH_WRITE_REF_delete_dead_snapshots);
 }
 
 int __bch2_key_has_snapshot_overwrites(struct btree_trans *trans,
diff --git a/libbcachefs/str_hash.h b/libbcachefs/str_hash.h
index 09a354a2..a67ee4ad 100644
--- a/libbcachefs/str_hash.h
+++ b/libbcachefs/str_hash.h
@@ -48,7 +48,7 @@ bch2_hash_info_init(struct bch_fs *c, const struct bch_inode_unpacked *bi)
 	struct bch_hash_info info = {
 		.type = INODE_STR_HASH(bi),
 #ifdef CONFIG_UNICODE
-		.cf_encoding = !!(bi->bi_flags & BCH_INODE_casefolded) ? c->cf_encoding : NULL,
+		.cf_encoding = bi->bi_casefold ? c->cf_encoding : NULL,
 #endif
 		.siphash_key = { .k0 = bi->bi_hash_seed }
 	};
diff --git a/libbcachefs/subvolume.c b/libbcachefs/subvolume.c
index 1b9fb60c..39376c87 100644
--- a/libbcachefs/subvolume.c
+++ b/libbcachefs/subvolume.c
@@ -3,6 +3,7 @@
 #include "bcachefs.h"
 #include "btree_key_cache.h"
 #include "btree_update.h"
+#include "enumerated_ref.h"
 #include "errcode.h"
 #include "error.h"
 #include "fs.h"
@@ -517,7 +518,7 @@ static void bch2_subvolume_wait_for_pagecache_and_delete(struct work_struct *wor
 		darray_exit(&s);
 	}
 
-	bch2_write_ref_put(c, BCH_WRITE_REF_snapshot_delete_pagecache);
+	enumerated_ref_put(&c->writes, BCH_WRITE_REF_snapshot_delete_pagecache);
 }
 
 struct subvolume_unlink_hook {
@@ -540,11 +541,11 @@ static int bch2_subvolume_wait_for_pagecache_and_delete_hook(struct btree_trans
 	if (ret)
 		return ret;
 
-	if (!bch2_write_ref_tryget(c, BCH_WRITE_REF_snapshot_delete_pagecache))
+	if (!enumerated_ref_tryget(&c->writes, BCH_WRITE_REF_snapshot_delete_pagecache))
 		return -EROFS;
 
 	if (!queue_work(c->write_ref_wq, &c->snapshot_wait_for_pagecache_and_delete_work))
-		bch2_write_ref_put(c, BCH_WRITE_REF_snapshot_delete_pagecache);
+		enumerated_ref_put(&c->writes, BCH_WRITE_REF_snapshot_delete_pagecache);
 	return 0;
 }
 
diff --git a/libbcachefs/super-io.c b/libbcachefs/super-io.c
index bc2721b9..d53cbc5f 100644
--- a/libbcachefs/super-io.c
+++ b/libbcachefs/super-io.c
@@ -260,11 +260,11 @@ struct bch_sb_field *bch2_sb_field_resize_id(struct bch_sb_handle *sb,
 
 		/* XXX: we're not checking that offline device have enough space */
 
-		for_each_online_member(c, ca) {
+		for_each_online_member(c, ca, BCH_DEV_READ_REF_sb_field_resize) {
 			struct bch_sb_handle *dev_sb = &ca->disk_sb;
 
 			if (bch2_sb_realloc(dev_sb, le32_to_cpu(dev_sb->sb->u64s) + d)) {
-				percpu_ref_put(&ca->io_ref[READ]);
+				enumerated_ref_put(&ca->io_ref[READ], BCH_DEV_READ_REF_sb_field_resize);
 				return NULL;
 			}
 		}
@@ -967,7 +967,7 @@ static void write_super_endio(struct bio *bio)
 	}
 
 	closure_put(&ca->fs->sb_write);
-	percpu_ref_put(&ca->io_ref[READ]);
+	enumerated_ref_put(&ca->io_ref[READ], BCH_DEV_READ_REF_write_super);
 }
 
 static void read_back_super(struct bch_fs *c, struct bch_dev *ca)
@@ -985,7 +985,7 @@ static void read_back_super(struct bch_fs *c, struct bch_dev *ca)
 
 	this_cpu_add(ca->io_done->sectors[READ][BCH_DATA_sb], bio_sectors(bio));
 
-	percpu_ref_get(&ca->io_ref[READ]);
+	enumerated_ref_get(&ca->io_ref[READ], BCH_DEV_READ_REF_write_super);
 	closure_bio_submit(bio, &c->sb_write);
 }
 
@@ -1011,7 +1011,7 @@ static void write_one_super(struct bch_fs *c, struct bch_dev *ca, unsigned idx)
 	this_cpu_add(ca->io_done->sectors[WRITE][BCH_DATA_sb],
 		     bio_sectors(bio));
 
-	percpu_ref_get(&ca->io_ref[READ]);
+	enumerated_ref_get(&ca->io_ref[READ], BCH_DEV_READ_REF_write_super);
 	closure_bio_submit(bio, &c->sb_write);
 }
 
@@ -1043,13 +1043,13 @@ int bch2_write_super(struct bch_fs *c)
 	 * For now, we expect to be able to call write_super() when we're not
 	 * yet RW:
 	 */
-	for_each_online_member(c, ca) {
+	for_each_online_member(c, ca, BCH_DEV_READ_REF_write_super) {
 		ret = darray_push(&online_devices, ca);
 		if (bch2_fs_fatal_err_on(ret, c, "%s: error allocating online devices", __func__)) {
-			percpu_ref_put(&ca->io_ref[READ]);
+			enumerated_ref_put(&ca->io_ref[READ], BCH_DEV_READ_REF_write_super);
 			goto out;
 		}
-		percpu_ref_get(&ca->io_ref[READ]);
+		enumerated_ref_get(&ca->io_ref[READ], BCH_DEV_READ_REF_write_super);
 	}
 
 	/* Make sure we're using the new magic numbers: */
@@ -1108,7 +1108,8 @@ int bch2_write_super(struct bch_fs *c)
 		prt_str(&buf, ")");
 		bch2_fs_fatal_error(c, ": %s", buf.buf);
 		printbuf_exit(&buf);
-		return -BCH_ERR_sb_not_downgraded;
+		ret = -BCH_ERR_sb_not_downgraded;
+		goto out;
 	}
 
 	darray_for_each(online_devices, ca) {
@@ -1215,7 +1216,7 @@ out:
 	/* Make new options visible after they're persistent: */
 	bch2_sb_update(c);
 	darray_for_each(online_devices, ca)
-		percpu_ref_put(&(*ca)->io_ref[READ]);
+		enumerated_ref_put(&(*ca)->io_ref[READ], BCH_DEV_READ_REF_write_super);
 	darray_exit(&online_devices);
 	printbuf_exit(&err);
 	return ret;
diff --git a/libbcachefs/super.c b/libbcachefs/super.c
index 4632230f..f861583c 100644
--- a/libbcachefs/super.c
+++ b/libbcachefs/super.c
@@ -10,6 +10,7 @@
 #include "bcachefs.h"
 #include "alloc_background.h"
 #include "alloc_foreground.h"
+#include "async_objs.h"
 #include "bkey_sort.h"
 #include "btree_cache.h"
 #include "btree_gc.h"
@@ -28,6 +29,7 @@
 #include "disk_accounting.h"
 #include "disk_groups.h"
 #include "ec.h"
+#include "enumerated_ref.h"
 #include "errcode.h"
 #include "error.h"
 #include "fs.h"
@@ -77,13 +79,28 @@ MODULE_DESCRIPTION("bcachefs filesystem");
 
 typedef DARRAY(struct bch_sb_handle) bch_sb_handles;
 
-const char * const bch2_fs_flag_strs[] = {
 #define x(n)		#n,
+const char * const bch2_fs_flag_strs[] = {
 	BCH_FS_FLAGS()
-#undef x
 	NULL
 };
 
+const char * const bch2_write_refs[] = {
+	BCH_WRITE_REFS()
+	NULL
+};
+
+const char * const bch2_dev_read_refs[] = {
+	BCH_DEV_READ_REFS()
+	NULL
+};
+
+const char * const bch2_dev_write_refs[] = {
+	BCH_DEV_WRITE_REFS()
+	NULL
+};
+#undef x
+
 static void __bch2_print_str(struct bch_fs *c, const char *prefix,
 			     const char *str, bool nonblocking)
 {
@@ -311,15 +328,13 @@ static void __bch2_fs_read_only(struct bch_fs *c)
 	}
 }
 
-#ifndef BCH_WRITE_REF_DEBUG
-static void bch2_writes_disabled(struct percpu_ref *writes)
+static void bch2_writes_disabled(struct enumerated_ref *writes)
 {
 	struct bch_fs *c = container_of(writes, struct bch_fs, writes);
 
 	set_bit(BCH_FS_write_disable_complete, &c->flags);
 	wake_up(&bch2_read_only_wait);
 }
-#endif
 
 void bch2_fs_read_only(struct bch_fs *c)
 {
@@ -337,12 +352,7 @@ void bch2_fs_read_only(struct bch_fs *c)
 	 * writes will return -EROFS:
 	 */
 	set_bit(BCH_FS_going_ro, &c->flags);
-#ifndef BCH_WRITE_REF_DEBUG
-	percpu_ref_kill(&c->writes);
-#else
-	for (unsigned i = 0; i < BCH_WRITE_REF_NR; i++)
-		bch2_write_ref_put(c, i);
-#endif
+	enumerated_ref_stop_async(&c->writes);
 
 	/*
 	 * If we're not doing an emergency shutdown, we want to wait on
@@ -432,32 +442,6 @@ bool bch2_fs_emergency_read_only_locked(struct bch_fs *c)
 	return ret;
 }
 
-static int bch2_fs_read_write_late(struct bch_fs *c)
-{
-	int ret;
-
-	/*
-	 * Data move operations can't run until after check_snapshots has
-	 * completed, and bch2_snapshot_is_ancestor() is available.
-	 *
-	 * Ideally we'd start copygc/rebalance earlier instead of waiting for
-	 * all of recovery/fsck to complete:
-	 */
-	ret = bch2_copygc_start(c);
-	if (ret) {
-		bch_err(c, "error starting copygc thread");
-		return ret;
-	}
-
-	ret = bch2_rebalance_start(c);
-	if (ret) {
-		bch_err(c, "error starting rebalance thread");
-		return ret;
-	}
-
-	return 0;
-}
-
 static int __bch2_fs_read_write(struct bch_fs *c, bool early)
 {
 	int ret;
@@ -492,10 +476,14 @@ static int __bch2_fs_read_write(struct bch_fs *c, bool early)
 
 	clear_bit(BCH_FS_clean_shutdown, &c->flags);
 
-	__for_each_online_member(c, ca, BIT(BCH_MEMBER_STATE_rw), READ) {
-		bch2_dev_allocator_add(c, ca);
-		percpu_ref_reinit(&ca->io_ref[WRITE]);
-	}
+	rcu_read_lock();
+	for_each_online_member_rcu(c, ca)
+		if (ca->mi.state == BCH_MEMBER_STATE_rw) {
+			bch2_dev_allocator_add(c, ca);
+			enumerated_ref_start(&ca->io_ref[WRITE]);
+		}
+	rcu_read_unlock();
+
 	bch2_recalc_capacity(c);
 
 	/*
@@ -521,18 +509,18 @@ static int __bch2_fs_read_write(struct bch_fs *c, bool early)
 	set_bit(BCH_FS_rw, &c->flags);
 	set_bit(BCH_FS_was_rw, &c->flags);
 
-#ifndef BCH_WRITE_REF_DEBUG
-	percpu_ref_reinit(&c->writes);
-#else
-	for (unsigned i = 0; i < BCH_WRITE_REF_NR; i++) {
-		BUG_ON(atomic_long_read(&c->writes[i]));
-		atomic_long_inc(&c->writes[i]);
+	enumerated_ref_start(&c->writes);
+
+	ret = bch2_copygc_start(c);
+	if (ret) {
+		bch_err_msg(c, ret, "error starting copygc thread");
+		goto err;
 	}
-#endif
-	if (!early) {
-		ret = bch2_fs_read_write_late(c);
-		if (ret)
-			goto err;
+
+	ret = bch2_rebalance_start(c);
+	if (ret) {
+		bch_err_msg(c, ret, "error starting rebalance thread");
+		goto err;
 	}
 
 	bch2_do_discards(c);
@@ -583,6 +571,7 @@ static void __bch2_fs_free(struct bch_fs *c)
 	bch2_free_pending_node_rewrites(c);
 	bch2_free_fsck_errs(c);
 	bch2_fs_accounting_exit(c);
+	bch2_fs_async_obj_exit(c);
 	bch2_fs_sb_errors_exit(c);
 	bch2_fs_counters_exit(c);
 	bch2_fs_snapshots_exit(c);
@@ -625,9 +614,7 @@ static void __bch2_fs_free(struct bch_fs *c)
 	mempool_exit(&c->btree_bounce_pool);
 	bioset_exit(&c->btree_bio);
 	mempool_exit(&c->fill_iter);
-#ifndef BCH_WRITE_REF_DEBUG
-	percpu_ref_exit(&c->writes);
-#endif
+	enumerated_ref_exit(&c->writes);
 	kfree(rcu_dereference_protected(c->disk_groups, 1));
 	kfree(c->journal_seq_blacklist_table);
 
@@ -666,6 +653,12 @@ void __bch2_fs_stop(struct bch_fs *c)
 	bch2_fs_read_only(c);
 	up_write(&c->state_lock);
 
+	for (unsigned i = 0; i < c->sb.nr_devices; i++) {
+		struct bch_dev *ca = rcu_dereference_protected(c->devs[i], true);
+		if (ca)
+			bch2_dev_io_ref_stop(ca, READ);
+	}
+
 	for_each_member_device(c, ca)
 		bch2_dev_unlink(ca);
 
@@ -694,8 +687,6 @@ void __bch2_fs_stop(struct bch_fs *c)
 
 void bch2_fs_free(struct bch_fs *c)
 {
-	unsigned i;
-
 	mutex_lock(&bch_fs_list_lock);
 	list_del(&c->list);
 	mutex_unlock(&bch_fs_list_lock);
@@ -703,7 +694,7 @@ void bch2_fs_free(struct bch_fs *c)
 	closure_sync(&c->cl);
 	closure_debug_destroy(&c->cl);
 
-	for (i = 0; i < c->sb.nr_devices; i++) {
+	for (unsigned i = 0; i < c->sb.nr_devices; i++) {
 		struct bch_dev *ca = rcu_dereference_protected(c->devs[i], true);
 
 		if (ca) {
@@ -974,10 +965,8 @@ static struct bch_fs *bch2_fs_alloc(struct bch_sb *sb, struct bch_opts opts,
 
 	if (!(c->btree_read_complete_wq = alloc_workqueue("bcachefs_btree_read_complete",
 				WQ_HIGHPRI|WQ_FREEZABLE|WQ_MEM_RECLAIM, 512)) ||
-#ifndef BCH_WRITE_REF_DEBUG
-	    percpu_ref_init(&c->writes, bch2_writes_disabled,
-			    PERCPU_REF_INIT_DEAD, GFP_KERNEL) ||
-#endif
+	    enumerated_ref_init(&c->writes, BCH_WRITE_REF_NR,
+				bch2_writes_disabled) ||
 	    mempool_init_kmalloc_pool(&c->fill_iter, 1, iter_size) ||
 	    bioset_init(&c->btree_bio, 1,
 			max(offsetof(struct btree_read_bio, bio),
@@ -994,6 +983,7 @@ static struct bch_fs *bch2_fs_alloc(struct bch_sb *sb, struct bch_opts opts,
 	}
 
 	ret =
+	    bch2_fs_async_obj_init(c) ?:
 	    bch2_fs_btree_cache_init(c) ?:
 	    bch2_fs_btree_iter_init(c) ?:
 	    bch2_fs_btree_key_cache_init(&c->btree_key_cache) ?:
@@ -1107,14 +1097,20 @@ int bch2_fs_start(struct bch_fs *c)
 		goto err;
 	}
 
-	for_each_online_member(c, ca)
-		bch2_members_v2_get_mut(c->disk_sb.sb, ca->dev_idx)->last_mount = cpu_to_le64(now);
+	rcu_read_lock();
+	for_each_online_member_rcu(c, ca)
+		bch2_members_v2_get_mut(c->disk_sb.sb, ca->dev_idx)->last_mount =
+		cpu_to_le64(now);
+	rcu_read_unlock();
 
 	bch2_write_super(c);
 	mutex_unlock(&c->sb_lock);
 
-	for_each_rw_member(c, ca)
-		bch2_dev_allocator_add(c, ca);
+	rcu_read_lock();
+	for_each_online_member_rcu(c, ca)
+		if (ca->mi.state == BCH_MEMBER_STATE_rw)
+			bch2_dev_allocator_add(c, ca);
+	rcu_read_unlock();
 	bch2_recalc_capacity(c);
 	up_write(&c->state_lock);
 
@@ -1140,13 +1136,10 @@ int bch2_fs_start(struct bch_fs *c)
 	wake_up(&c->ro_ref_wait);
 
 	down_write(&c->state_lock);
-	if (c->opts.read_only) {
+	if (c->opts.read_only)
 		bch2_fs_read_only(c);
-	} else {
-		ret = !test_bit(BCH_FS_rw, &c->flags)
-			? bch2_fs_read_write(c)
-			: bch2_fs_read_write_late(c);
-	}
+	else if (!test_bit(BCH_FS_rw, &c->flags))
+		ret = bch2_fs_read_write(c);
 	up_write(&c->state_lock);
 
 err:
@@ -1264,11 +1257,14 @@ static int bch2_dev_in_fs(struct bch_sb_handle *fs,
 
 static void bch2_dev_io_ref_stop(struct bch_dev *ca, int rw)
 {
-	if (!percpu_ref_is_zero(&ca->io_ref[rw])) {
-		reinit_completion(&ca->io_ref_completion[rw]);
-		percpu_ref_kill(&ca->io_ref[rw]);
-		wait_for_completion(&ca->io_ref_completion[rw]);
-	}
+	if (rw == READ)
+		clear_bit(ca->dev_idx, ca->fs->online_devs.d);
+
+	if (!enumerated_ref_is_zero(&ca->io_ref[rw]))
+		enumerated_ref_stop(&ca->io_ref[rw],
+				    rw == READ
+				    ? bch2_dev_read_refs
+				    : bch2_dev_write_refs);
 }
 
 static void bch2_dev_release(struct kobject *kobj)
@@ -1280,8 +1276,8 @@ static void bch2_dev_release(struct kobject *kobj)
 
 static void bch2_dev_free(struct bch_dev *ca)
 {
-	WARN_ON(!percpu_ref_is_zero(&ca->io_ref[WRITE]));
-	WARN_ON(!percpu_ref_is_zero(&ca->io_ref[READ]));
+	WARN_ON(!enumerated_ref_is_zero(&ca->io_ref[WRITE]));
+	WARN_ON(!enumerated_ref_is_zero(&ca->io_ref[READ]));
 
 	cancel_work_sync(&ca->io_error_work);
 
@@ -1301,8 +1297,8 @@ static void bch2_dev_free(struct bch_dev *ca)
 	bch2_time_stats_quantiles_exit(&ca->io_latency[WRITE]);
 	bch2_time_stats_quantiles_exit(&ca->io_latency[READ]);
 
-	percpu_ref_exit(&ca->io_ref[WRITE]);
-	percpu_ref_exit(&ca->io_ref[READ]);
+	enumerated_ref_exit(&ca->io_ref[WRITE]);
+	enumerated_ref_exit(&ca->io_ref[READ]);
 #ifndef CONFIG_BCACHEFS_DEBUG
 	percpu_ref_exit(&ca->ref);
 #endif
@@ -1314,7 +1310,7 @@ static void __bch2_dev_offline(struct bch_fs *c, struct bch_dev *ca)
 
 	lockdep_assert_held(&c->state_lock);
 
-	if (percpu_ref_is_zero(&ca->io_ref[READ]))
+	if (enumerated_ref_is_zero(&ca->io_ref[READ]))
 		return;
 
 	__bch2_dev_read_only(c, ca);
@@ -1336,20 +1332,6 @@ static void bch2_dev_ref_complete(struct percpu_ref *ref)
 }
 #endif
 
-static void bch2_dev_io_ref_read_complete(struct percpu_ref *ref)
-{
-	struct bch_dev *ca = container_of(ref, struct bch_dev, io_ref[READ]);
-
-	complete(&ca->io_ref_completion[READ]);
-}
-
-static void bch2_dev_io_ref_write_complete(struct percpu_ref *ref)
-{
-	struct bch_dev *ca = container_of(ref, struct bch_dev, io_ref[WRITE]);
-
-	complete(&ca->io_ref_completion[WRITE]);
-}
-
 static void bch2_dev_unlink(struct bch_dev *ca)
 {
 	struct kobject *b;
@@ -1411,8 +1393,6 @@ static struct bch_dev *__bch2_dev_alloc(struct bch_fs *c,
 
 	kobject_init(&ca->kobj, &bch2_dev_ktype);
 	init_completion(&ca->ref_completion);
-	init_completion(&ca->io_ref_completion[READ]);
-	init_completion(&ca->io_ref_completion[WRITE]);
 
 	INIT_WORK(&ca->io_error_work, bch2_io_error_work);
 
@@ -1438,10 +1418,8 @@ static struct bch_dev *__bch2_dev_alloc(struct bch_fs *c,
 
 	bch2_dev_allocator_background_init(ca);
 
-	if (percpu_ref_init(&ca->io_ref[READ], bch2_dev_io_ref_read_complete,
-			    PERCPU_REF_INIT_DEAD, GFP_KERNEL) ||
-	    percpu_ref_init(&ca->io_ref[WRITE], bch2_dev_io_ref_write_complete,
-			    PERCPU_REF_INIT_DEAD, GFP_KERNEL) ||
+	if (enumerated_ref_init(&ca->io_ref[READ],  BCH_DEV_READ_REF_NR,  NULL) ||
+	    enumerated_ref_init(&ca->io_ref[WRITE], BCH_DEV_WRITE_REF_NR, NULL) ||
 	    !(ca->sb_read_scratch = kmalloc(BCH_SB_READ_SCRATCH_BUF_SIZE, GFP_KERNEL)) ||
 	    bch2_dev_buckets_alloc(c, ca) ||
 	    !(ca->io_done	= alloc_percpu(*ca->io_done)))
@@ -1503,8 +1481,8 @@ static int __bch2_dev_attach_bdev(struct bch_dev *ca, struct bch_sb_handle *sb)
 		return -BCH_ERR_device_size_too_small;
 	}
 
-	BUG_ON(!percpu_ref_is_zero(&ca->io_ref[READ]));
-	BUG_ON(!percpu_ref_is_zero(&ca->io_ref[WRITE]));
+	BUG_ON(!enumerated_ref_is_zero(&ca->io_ref[READ]));
+	BUG_ON(!enumerated_ref_is_zero(&ca->io_ref[WRITE]));
 
 	ret = bch2_dev_journal_init(ca, sb->sb);
 	if (ret)
@@ -1523,7 +1501,7 @@ static int __bch2_dev_attach_bdev(struct bch_dev *ca, struct bch_sb_handle *sb)
 
 	ca->dev = ca->disk_sb.bdev->bd_dev;
 
-	percpu_ref_reinit(&ca->io_ref[READ]);
+	enumerated_ref_start(&ca->io_ref[READ]);
 
 	return 0;
 }
@@ -1547,6 +1525,8 @@ static int bch2_dev_attach_bdev(struct bch_fs *c, struct bch_sb_handle *sb)
 	if (ret)
 		return ret;
 
+	set_bit(ca->dev_idx, c->online_devs.d);
+
 	bch2_dev_sysfs_online(c, ca);
 
 	struct printbuf name = PRINTBUF;
@@ -1604,7 +1584,7 @@ bool bch2_dev_state_allowed(struct bch_fs *c, struct bch_dev *ca,
 			return true;
 
 		/* do we have enough devices to read from?  */
-		new_online_devs = bch2_online_devs(c);
+		new_online_devs = c->online_devs;
 		__clear_bit(ca->dev_idx, new_online_devs.d);
 
 		return bch2_have_enough_devs(c, new_online_devs, flags, false);
@@ -1644,7 +1624,7 @@ static bool bch2_fs_may_start(struct bch_fs *c)
 		break;
 	}
 
-	return bch2_have_enough_devs(c, bch2_online_devs(c), flags, true);
+	return bch2_have_enough_devs(c, c->online_devs, flags, true);
 }
 
 static void __bch2_dev_read_only(struct bch_fs *c, struct bch_dev *ca)
@@ -1668,8 +1648,8 @@ static void __bch2_dev_read_write(struct bch_fs *c, struct bch_dev *ca)
 	bch2_dev_allocator_add(c, ca);
 	bch2_recalc_capacity(c);
 
-	if (percpu_ref_is_zero(&ca->io_ref[WRITE]))
-		percpu_ref_reinit(&ca->io_ref[WRITE]);
+	if (enumerated_ref_is_zero(&ca->io_ref[WRITE]))
+		enumerated_ref_start(&ca->io_ref[WRITE]);
 
 	bch2_dev_do_discards(ca);
 }
@@ -1819,7 +1799,7 @@ int bch2_dev_remove(struct bch_fs *c, struct bch_dev *ca, int flags)
 err:
 	if (test_bit(BCH_FS_rw, &c->flags) &&
 	    ca->mi.state == BCH_MEMBER_STATE_rw &&
-	    !percpu_ref_is_zero(&ca->io_ref[READ]))
+	    !enumerated_ref_is_zero(&ca->io_ref[READ]))
 		__bch2_dev_read_write(c, ca);
 	up_write(&c->state_lock);
 	return ret;
@@ -2120,7 +2100,7 @@ int bch2_fs_resize_on_mount(struct bch_fs *c)
 {
 	down_write(&c->state_lock);
 
-	for_each_online_member(c, ca) {
+	for_each_online_member(c, ca, BCH_DEV_READ_REF_fs_resize_on_mount) {
 		u64 old_nbuckets = ca->mi.nbuckets;
 		u64 new_nbuckets = div64_u64(get_capacity(ca->disk_sb.bdev->bd_disk),
 					 ca->mi.bucket_size);
@@ -2131,7 +2111,8 @@ int bch2_fs_resize_on_mount(struct bch_fs *c)
 			int ret = bch2_dev_buckets_resize(c, ca, new_nbuckets);
 			bch_err_fn(ca, ret);
 			if (ret) {
-				percpu_ref_put(&ca->io_ref[READ]);
+				enumerated_ref_put(&ca->io_ref[READ],
+						   BCH_DEV_READ_REF_fs_resize_on_mount);
 				up_write(&c->state_lock);
 				return ret;
 			}
@@ -2149,7 +2130,8 @@ int bch2_fs_resize_on_mount(struct bch_fs *c)
 			if (ca->mi.freespace_initialized) {
 				ret = __bch2_dev_resize_alloc(ca, old_nbuckets, new_nbuckets);
 				if (ret) {
-					percpu_ref_put(&ca->io_ref[READ]);
+					enumerated_ref_put(&ca->io_ref[READ],
+							BCH_DEV_READ_REF_fs_resize_on_mount);
 					up_write(&c->state_lock);
 					return ret;
 				}
diff --git a/libbcachefs/super.h b/libbcachefs/super.h
index 502d6c57..dbf59547 100644
--- a/libbcachefs/super.h
+++ b/libbcachefs/super.h
@@ -9,6 +9,9 @@
 #include <linux/math64.h>
 
 extern const char * const bch2_fs_flag_strs[];
+extern const char * const bch2_write_refs[];
+extern const char * const bch2_dev_read_refs[];
+extern const char * const bch2_dev_write_refs[];
 
 struct bch_fs *bch2_dev_to_fs(dev_t);
 struct bch_fs *bch2_uuid_to_fs(__uuid_t);
diff --git a/libbcachefs/sysfs.c b/libbcachefs/sysfs.c
index 455c6ae9..7c840b47 100644
--- a/libbcachefs/sysfs.c
+++ b/libbcachefs/sysfs.c
@@ -25,6 +25,7 @@
 #include "disk_accounting.h"
 #include "disk_groups.h"
 #include "ec.h"
+#include "enumerated_ref.h"
 #include "inode.h"
 #include "journal.h"
 #include "journal_reclaim.h"
@@ -178,25 +179,9 @@ read_attribute(open_buckets);
 read_attribute(open_buckets_partial);
 read_attribute(nocow_lock_table);
 
-#ifdef BCH_WRITE_REF_DEBUG
+read_attribute(read_refs);
 read_attribute(write_refs);
 
-static const char * const bch2_write_refs[] = {
-#define x(n)	#n,
-	BCH_WRITE_REFS()
-#undef x
-	NULL
-};
-
-static void bch2_write_refs_to_text(struct printbuf *out, struct bch_fs *c)
-{
-	bch2_printbuf_tabstop_push(out, 24);
-
-	for (unsigned i = 0; i < ARRAY_SIZE(c->writes); i++)
-		prt_printf(out, "%s\t%li\n", bch2_write_refs[i], atomic_long_read(&c->writes[i]));
-}
-#endif
-
 read_attribute(internal_uuid);
 read_attribute(disk_groups);
 
@@ -324,7 +309,7 @@ static int bch2_read_fua_test(struct printbuf *out, struct bch_dev *ca)
 	bch2_time_stats_init_no_pcpu(&stats_fua);
 	bch2_time_stats_init_no_pcpu(&stats_random);
 
-	if (!bch2_dev_get_ioref(c, ca->dev_idx, READ)) {
+	if (!bch2_dev_get_ioref(c, ca->dev_idx, READ, BCH_DEV_READ_REF_read_fua_test)) {
 		prt_str(out, "offline\n");
 		return 0;
 	}
@@ -415,7 +400,7 @@ static int bch2_read_fua_test(struct printbuf *out, struct bch_dev *ca)
 err:
 	kfree(buf);
 	kfree(bio);
-	percpu_ref_put(&ca->io_ref[READ]);
+	enumerated_ref_put(&ca->io_ref[READ], BCH_DEV_READ_REF_read_fua_test);
 	bch_err_fn(c, ret);
 	return ret;
 }
@@ -481,10 +466,8 @@ SHOW(bch2_fs)
 	if (attr == &sysfs_moving_ctxts)
 		bch2_fs_moving_ctxts_to_text(out, c);
 
-#ifdef BCH_WRITE_REF_DEBUG
 	if (attr == &sysfs_write_refs)
-		bch2_write_refs_to_text(out, c);
-#endif
+		enumerated_ref_to_text(out, &c->writes, bch2_write_refs);
 
 	if (attr == &sysfs_nocow_lock_table)
 		bch2_nocow_locks_to_text(out, &c->nocow_locks);
@@ -517,7 +500,7 @@ STORE(bch2_fs)
 	if (attr == &sysfs_trigger_btree_updates)
 		queue_work(c->btree_interior_update_worker, &c->btree_interior_update_work);
 
-	if (!bch2_write_ref_tryget(c, BCH_WRITE_REF_sysfs))
+	if (!enumerated_ref_tryget(&c->writes, BCH_WRITE_REF_sysfs))
 		return -EROFS;
 
 	if (attr == &sysfs_trigger_btree_cache_shrink) {
@@ -577,7 +560,7 @@ STORE(bch2_fs)
 			size = ret;
 	}
 #endif
-	bch2_write_ref_put(c, BCH_WRITE_REF_sysfs);
+	enumerated_ref_put(&c->writes, BCH_WRITE_REF_sysfs);
 	return size;
 }
 SYSFS_OPS(bch2_fs);
@@ -670,9 +653,7 @@ struct attribute *bch2_fs_internal_files[] = {
 	&sysfs_new_stripes,
 	&sysfs_open_buckets,
 	&sysfs_open_buckets_partial,
-#ifdef BCH_WRITE_REF_DEBUG
 	&sysfs_write_refs,
-#endif
 	&sysfs_nocow_lock_table,
 	&sysfs_io_timers_read,
 	&sysfs_io_timers_write,
@@ -738,7 +719,7 @@ static ssize_t sysfs_opt_store(struct bch_fs *c,
 	 * We don't need to take c->writes for correctness, but it eliminates an
 	 * unsightly error message in the dmesg log when we're RO:
 	 */
-	if (unlikely(!bch2_write_ref_tryget(c, BCH_WRITE_REF_sysfs)))
+	if (unlikely(!enumerated_ref_tryget(&c->writes, BCH_WRITE_REF_sysfs)))
 		return -EROFS;
 
 	char *tmp = kstrdup(buf, GFP_KERNEL);
@@ -765,7 +746,7 @@ static ssize_t sysfs_opt_store(struct bch_fs *c,
 
 	ret = size;
 err:
-	bch2_write_ref_put(c, BCH_WRITE_REF_sysfs);
+	enumerated_ref_put(&c->writes, BCH_WRITE_REF_sysfs);
 	return ret;
 }
 
@@ -919,6 +900,12 @@ SHOW(bch2_dev)
 	if (opt_id >= 0)
 		return sysfs_opt_show(c, ca, opt_id, out);
 
+	if (attr == &sysfs_read_refs)
+		enumerated_ref_to_text(out, &ca->io_ref[READ], bch2_dev_read_refs);
+
+	if (attr == &sysfs_write_refs)
+		enumerated_ref_to_text(out, &ca->io_ref[WRITE], bch2_dev_write_refs);
+
 	return 0;
 }
 
@@ -976,6 +963,9 @@ struct attribute *bch2_dev_files[] = {
 	/* debug: */
 	&sysfs_alloc_debug,
 	&sysfs_open_buckets,
+
+	&sysfs_read_refs,
+	&sysfs_write_refs,
 	NULL
 };
 
diff --git a/libbcachefs/util.c b/libbcachefs/util.c
index 6e5d7fc2..7e6ebe8c 100644
--- a/libbcachefs/util.c
+++ b/libbcachefs/util.c
@@ -715,6 +715,16 @@ void bch2_corrupt_bio(struct bio *bio)
 }
 #endif
 
+void bch2_bio_to_text(struct printbuf *out, struct bio *bio)
+{
+	prt_printf(out, "bi_remaining:\t%u\n",
+		   atomic_read(&bio->__bi_remaining));
+	prt_printf(out, "bi_end_io:\t%ps\n",
+		   bio->bi_end_io);
+	prt_printf(out, "bi_status:\t%u\n",
+		   bio->bi_status);
+}
+
 #if 0
 void eytzinger1_test(void)
 {
diff --git a/libbcachefs/util.h b/libbcachefs/util.h
index fa742af9..7a93e187 100644
--- a/libbcachefs/util.h
+++ b/libbcachefs/util.h
@@ -419,6 +419,8 @@ static inline void bch2_maybe_corrupt_bio(struct bio *bio, unsigned ratio)
 #define bch2_maybe_corrupt_bio(...)	do {} while (0)
 #endif
 
+void bch2_bio_to_text(struct printbuf *, struct bio *);
+
 static inline void memcpy_u64s_small(void *dst, const void *src,
 				     unsigned u64s)
 {
@@ -739,4 +741,42 @@ static inline void memcpy_swab(void *_dst, void *_src, size_t len)
 		*--dst = *src++;
 }
 
+#define set_flags(_map, _in, _out)					\
+do {									\
+	unsigned _i;							\
+									\
+	for (_i = 0; _i < ARRAY_SIZE(_map); _i++)			\
+		if ((_in) & (1 << _i))					\
+			(_out) |= _map[_i];				\
+		else							\
+			(_out) &= ~_map[_i];				\
+} while (0)
+
+#define map_flags(_map, _in)						\
+({									\
+	unsigned _out = 0;						\
+									\
+	set_flags(_map, _in, _out);					\
+	_out;								\
+})
+
+#define map_flags_rev(_map, _in)					\
+({									\
+	unsigned _i, _out = 0;						\
+									\
+	for (_i = 0; _i < ARRAY_SIZE(_map); _i++)			\
+		if ((_in) & _map[_i]) {					\
+			(_out) |= 1 << _i;				\
+			(_in) &= ~_map[_i];				\
+		}							\
+	(_out);								\
+})
+
+#define map_defined(_map)						\
+({									\
+	unsigned _in = ~0;						\
+									\
+	map_flags_rev(_map, _in);					\
+})
+
 #endif /* _BCACHEFS_UTIL_H */
diff --git a/linux/wait.c b/linux/wait.c
index b1f002b9..e5fe2cb9 100644
--- a/linux/wait.c
+++ b/linux/wait.c
@@ -248,3 +248,28 @@ void wait_for_completion(struct completion *x)
 out:
 	spin_unlock_irq(&x->wait.lock);
 }
+
+unsigned long wait_for_completion_timeout(struct completion *x, unsigned long timeout)
+{
+	spin_lock_irq(&x->wait.lock);
+
+	if (!x->done) {
+		DECLARE_WAITQUEUE(wait, current);
+
+		__add_wait_queue_tail_exclusive(&x->wait, &wait);
+		do {
+			__set_current_state(TASK_UNINTERRUPTIBLE);
+			spin_unlock_irq(&x->wait.lock);
+
+			timeout = schedule_timeout(timeout);
+			spin_lock_irq(&x->wait.lock);
+		} while (!x->done);
+		__remove_wait_queue(&x->wait, &wait);
+		if (!x->done)
+			goto out;
+	}
+	x->done--;
+out:
+	spin_unlock_irq(&x->wait.lock);
+	return timeout;
+}