Merging upstream version 6.7.7.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2170 insertions, 0 deletions

diff --git a/fs/bcachefs/buckets.c b/fs/bcachefs/buckets.c
new file mode 100644
index 0000000000..5a91d3189f
--- /dev/null
+++ b/fs/bcachefs/buckets.c
@@ -0,0 +1,2170 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Code for manipulating bucket marks for garbage collection.
+ *
+ * Copyright 2014 Datera, Inc.
+ */
+
+#include "bcachefs.h"
+#include "alloc_background.h"
+#include "backpointers.h"
+#include "bset.h"
+#include "btree_gc.h"
+#include "btree_update.h"
+#include "buckets.h"
+#include "buckets_waiting_for_journal.h"
+#include "ec.h"
+#include "error.h"
+#include "inode.h"
+#include "movinggc.h"
+#include "recovery.h"
+#include "reflink.h"
+#include "replicas.h"
+#include "subvolume.h"
+#include "trace.h"
+
+#include <linux/preempt.h>
+
+static inline void fs_usage_data_type_to_base(struct bch_fs_usage *fs_usage,
+					      enum bch_data_type data_type,
+					      s64 sectors)
+{
+	switch (data_type) {
+	case BCH_DATA_btree:
+		fs_usage->btree		+= sectors;
+		break;
+	case BCH_DATA_user:
+	case BCH_DATA_parity:
+		fs_usage->data		+= sectors;
+		break;
+	case BCH_DATA_cached:
+		fs_usage->cached	+= sectors;
+		break;
+	default:
+		break;
+	}
+}
+
+void bch2_fs_usage_initialize(struct bch_fs *c)
+{
+	struct bch_fs_usage *usage;
+	struct bch_dev *ca;
+	unsigned i;
+
+	percpu_down_write(&c->mark_lock);
+	usage = c->usage_base;
+
+	for (i = 0; i < ARRAY_SIZE(c->usage); i++)
+		bch2_fs_usage_acc_to_base(c, i);
+
+	for (i = 0; i < BCH_REPLICAS_MAX; i++)
+		usage->reserved += usage->persistent_reserved[i];
+
+	for (i = 0; i < c->replicas.nr; i++) {
+		struct bch_replicas_entry *e =
+			cpu_replicas_entry(&c->replicas, i);
+
+		fs_usage_data_type_to_base(usage, e->data_type, usage->replicas[i]);
+	}
+
+	for_each_member_device(ca, c, i) {
+		struct bch_dev_usage dev = bch2_dev_usage_read(ca);
+
+		usage->hidden += (dev.d[BCH_DATA_sb].buckets +
+				  dev.d[BCH_DATA_journal].buckets) *
+			ca->mi.bucket_size;
+	}
+
+	percpu_up_write(&c->mark_lock);
+}
+
+static inline struct bch_dev_usage *dev_usage_ptr(struct bch_dev *ca,
+						  unsigned journal_seq,
+						  bool gc)
+{
+	BUG_ON(!gc && !journal_seq);
+
+	return this_cpu_ptr(gc
+			    ? ca->usage_gc
+			    : ca->usage[journal_seq & JOURNAL_BUF_MASK]);
+}
+
+void bch2_dev_usage_read_fast(struct bch_dev *ca, struct bch_dev_usage *usage)
+{
+	struct bch_fs *c = ca->fs;
+	unsigned seq, i, u64s = dev_usage_u64s();
+
+	do {
+		seq = read_seqcount_begin(&c->usage_lock);
+		memcpy(usage, ca->usage_base, u64s * sizeof(u64));
+		for (i = 0; i < ARRAY_SIZE(ca->usage); i++)
+			acc_u64s_percpu((u64 *) usage, (u64 __percpu *) ca->usage[i], u64s);
+	} while (read_seqcount_retry(&c->usage_lock, seq));
+}
+
+u64 bch2_fs_usage_read_one(struct bch_fs *c, u64 *v)
+{
+	ssize_t offset = v - (u64 *) c->usage_base;
+	unsigned i, seq;
+	u64 ret;
+
+	BUG_ON(offset < 0 || offset >= fs_usage_u64s(c));
+	percpu_rwsem_assert_held(&c->mark_lock);
+
+	do {
+		seq = read_seqcount_begin(&c->usage_lock);
+		ret = *v;
+
+		for (i = 0; i < ARRAY_SIZE(c->usage); i++)
+			ret += percpu_u64_get((u64 __percpu *) c->usage[i] + offset);
+	} while (read_seqcount_retry(&c->usage_lock, seq));
+
+	return ret;
+}
+
+struct bch_fs_usage_online *bch2_fs_usage_read(struct bch_fs *c)
+{
+	struct bch_fs_usage_online *ret;
+	unsigned nr_replicas = READ_ONCE(c->replicas.nr);
+	unsigned seq, i;
+retry:
+	ret = kmalloc(__fs_usage_online_u64s(nr_replicas) * sizeof(u64), GFP_KERNEL);
+	if (unlikely(!ret))
+		return NULL;
+
+	percpu_down_read(&c->mark_lock);
+
+	if (nr_replicas != c->replicas.nr) {
+		nr_replicas = c->replicas.nr;
+		percpu_up_read(&c->mark_lock);
+		kfree(ret);
+		goto retry;
+	}
+
+	ret->online_reserved = percpu_u64_get(c->online_reserved);
+
+	do {
+		seq = read_seqcount_begin(&c->usage_lock);
+		unsafe_memcpy(&ret->u, c->usage_base,
+			      __fs_usage_u64s(nr_replicas) * sizeof(u64),
+			      "embedded variable length struct");
+		for (i = 0; i < ARRAY_SIZE(c->usage); i++)
+			acc_u64s_percpu((u64 *) &ret->u, (u64 __percpu *) c->usage[i],
+					__fs_usage_u64s(nr_replicas));
+	} while (read_seqcount_retry(&c->usage_lock, seq));
+
+	return ret;
+}
+
+void bch2_fs_usage_acc_to_base(struct bch_fs *c, unsigned idx)
+{
+	struct bch_dev *ca;
+	unsigned i, u64s = fs_usage_u64s(c);
+
+	BUG_ON(idx >= ARRAY_SIZE(c->usage));
+
+	preempt_disable();
+	write_seqcount_begin(&c->usage_lock);
+
+	acc_u64s_percpu((u64 *) c->usage_base,
+			(u64 __percpu *) c->usage[idx], u64s);
+	percpu_memset(c->usage[idx], 0, u64s * sizeof(u64));
+
+	rcu_read_lock();
+	for_each_member_device_rcu(ca, c, i, NULL) {
+		u64s = dev_usage_u64s();
+
+		acc_u64s_percpu((u64 *) ca->usage_base,
+				(u64 __percpu *) ca->usage[idx], u64s);
+		percpu_memset(ca->usage[idx], 0, u64s * sizeof(u64));
+	}
+	rcu_read_unlock();
+
+	write_seqcount_end(&c->usage_lock);
+	preempt_enable();
+}
+
+void bch2_fs_usage_to_text(struct printbuf *out,
+			   struct bch_fs *c,
+			   struct bch_fs_usage_online *fs_usage)
+{
+	unsigned i;
+
+	prt_printf(out, "capacity:\t\t\t%llu\n", c->capacity);
+
+	prt_printf(out, "hidden:\t\t\t\t%llu\n",
+	       fs_usage->u.hidden);
+	prt_printf(out, "data:\t\t\t\t%llu\n",
+	       fs_usage->u.data);
+	prt_printf(out, "cached:\t\t\t\t%llu\n",
+	       fs_usage->u.cached);
+	prt_printf(out, "reserved:\t\t\t%llu\n",
+	       fs_usage->u.reserved);
+	prt_printf(out, "nr_inodes:\t\t\t%llu\n",
+	       fs_usage->u.nr_inodes);
+	prt_printf(out, "online reserved:\t\t%llu\n",
+	       fs_usage->online_reserved);
+
+	for (i = 0;
+	     i < ARRAY_SIZE(fs_usage->u.persistent_reserved);
+	     i++) {
+		prt_printf(out, "%u replicas:\n", i + 1);
+		prt_printf(out, "\treserved:\t\t%llu\n",
+		       fs_usage->u.persistent_reserved[i]);
+	}
+
+	for (i = 0; i < c->replicas.nr; i++) {
+		struct bch_replicas_entry *e =
+			cpu_replicas_entry(&c->replicas, i);
+
+		prt_printf(out, "\t");
+		bch2_replicas_entry_to_text(out, e);
+		prt_printf(out, ":\t%llu\n", fs_usage->u.replicas[i]);
+	}
+}
+
+static u64 reserve_factor(u64 r)
+{
+	return r + (round_up(r, (1 << RESERVE_FACTOR)) >> RESERVE_FACTOR);
+}
+
+u64 bch2_fs_sectors_used(struct bch_fs *c, struct bch_fs_usage_online *fs_usage)
+{
+	return min(fs_usage->u.hidden +
+		   fs_usage->u.btree +
+		   fs_usage->u.data +
+		   reserve_factor(fs_usage->u.reserved +
+				  fs_usage->online_reserved),
+		   c->capacity);
+}
+
+static struct bch_fs_usage_short
+__bch2_fs_usage_read_short(struct bch_fs *c)
+{
+	struct bch_fs_usage_short ret;
+	u64 data, reserved;
+
+	ret.capacity = c->capacity -
+		bch2_fs_usage_read_one(c, &c->usage_base->hidden);
+
+	data		= bch2_fs_usage_read_one(c, &c->usage_base->data) +
+		bch2_fs_usage_read_one(c, &c->usage_base->btree);
+	reserved	= bch2_fs_usage_read_one(c, &c->usage_base->reserved) +
+		percpu_u64_get(c->online_reserved);
+
+	ret.used	= min(ret.capacity, data + reserve_factor(reserved));
+	ret.free	= ret.capacity - ret.used;
+
+	ret.nr_inodes	= bch2_fs_usage_read_one(c, &c->usage_base->nr_inodes);
+
+	return ret;
+}
+
+struct bch_fs_usage_short
+bch2_fs_usage_read_short(struct bch_fs *c)
+{
+	struct bch_fs_usage_short ret;
+
+	percpu_down_read(&c->mark_lock);
+	ret = __bch2_fs_usage_read_short(c);
+	percpu_up_read(&c->mark_lock);
+
+	return ret;
+}
+
+void bch2_dev_usage_init(struct bch_dev *ca)
+{
+	ca->usage_base->d[BCH_DATA_free].buckets = ca->mi.nbuckets - ca->mi.first_bucket;
+}
+
+static inline int bucket_sectors_fragmented(struct bch_dev *ca,
+					    struct bch_alloc_v4 a)
+{
+	return a.dirty_sectors
+		? max(0, (int) ca->mi.bucket_size - (int) a.dirty_sectors)
+		: 0;
+}
+
+static void bch2_dev_usage_update(struct bch_fs *c, struct bch_dev *ca,
+				  struct bch_alloc_v4 old,
+				  struct bch_alloc_v4 new,
+				  u64 journal_seq, bool gc)
+{
+	struct bch_fs_usage *fs_usage;
+	struct bch_dev_usage *u;
+
+	preempt_disable();
+	fs_usage = fs_usage_ptr(c, journal_seq, gc);
+
+	if (data_type_is_hidden(old.data_type))
+		fs_usage->hidden -= ca->mi.bucket_size;
+	if (data_type_is_hidden(new.data_type))
+		fs_usage->hidden += ca->mi.bucket_size;
+
+	u = dev_usage_ptr(ca, journal_seq, gc);
+
+	u->d[old.data_type].buckets--;
+	u->d[new.data_type].buckets++;
+
+	u->buckets_ec -= (int) !!old.stripe;
+	u->buckets_ec += (int) !!new.stripe;
+
+	u->d[old.data_type].sectors -= old.dirty_sectors;
+	u->d[new.data_type].sectors += new.dirty_sectors;
+
+	u->d[BCH_DATA_cached].sectors += new.cached_sectors;
+	u->d[BCH_DATA_cached].sectors -= old.cached_sectors;
+
+	u->d[old.data_type].fragmented -= bucket_sectors_fragmented(ca, old);
+	u->d[new.data_type].fragmented += bucket_sectors_fragmented(ca, new);
+
+	preempt_enable();
+}
+
+static void bch2_dev_usage_update_m(struct bch_fs *c, struct bch_dev *ca,
+				    struct bucket old, struct bucket new,
+				    u64 journal_seq, bool gc)
+{
+	struct bch_alloc_v4 old_a = {
+		.gen		= old.gen,
+		.data_type	= old.data_type,
+		.dirty_sectors	= old.dirty_sectors,
+		.cached_sectors	= old.cached_sectors,
+		.stripe		= old.stripe,
+	};
+	struct bch_alloc_v4 new_a = {
+		.gen		= new.gen,
+		.data_type	= new.data_type,
+		.dirty_sectors	= new.dirty_sectors,
+		.cached_sectors	= new.cached_sectors,
+		.stripe		= new.stripe,
+	};
+
+	bch2_dev_usage_update(c, ca, old_a, new_a, journal_seq, gc);
+}
+
+static inline int __update_replicas(struct bch_fs *c,
+				    struct bch_fs_usage *fs_usage,
+				    struct bch_replicas_entry *r,
+				    s64 sectors)
+{
+	int idx = bch2_replicas_entry_idx(c, r);
+
+	if (idx < 0)
+		return -1;
+
+	fs_usage_data_type_to_base(fs_usage, r->data_type, sectors);
+	fs_usage->replicas[idx]		+= sectors;
+	return 0;
+}
+
+static inline int update_replicas(struct bch_fs *c, struct bkey_s_c k,
+			struct bch_replicas_entry *r, s64 sectors,
+			unsigned journal_seq, bool gc)
+{
+	struct bch_fs_usage *fs_usage;
+	int idx, ret = 0;
+	struct printbuf buf = PRINTBUF;
+
+	percpu_down_read(&c->mark_lock);
+
+	idx = bch2_replicas_entry_idx(c, r);
+	if (idx < 0 &&
+	    fsck_err(c, ptr_to_missing_replicas_entry,
+		     "no replicas entry\n  while marking %s",
+		     (bch2_bkey_val_to_text(&buf, c, k), buf.buf))) {
+		percpu_up_read(&c->mark_lock);
+		ret = bch2_mark_replicas(c, r);
+		percpu_down_read(&c->mark_lock);
+
+		if (ret)
+			goto err;
+		idx = bch2_replicas_entry_idx(c, r);
+	}
+	if (idx < 0) {
+		ret = -1;
+		goto err;
+	}
+
+	preempt_disable();
+	fs_usage = fs_usage_ptr(c, journal_seq, gc);
+	fs_usage_data_type_to_base(fs_usage, r->data_type, sectors);
+	fs_usage->replicas[idx]		+= sectors;
+	preempt_enable();
+err:
+fsck_err:
+	percpu_up_read(&c->mark_lock);
+	printbuf_exit(&buf);
+	return ret;
+}
+
+static inline int update_cached_sectors(struct bch_fs *c,
+			struct bkey_s_c k,
+			unsigned dev, s64 sectors,
+			unsigned journal_seq, bool gc)
+{
+	struct bch_replicas_padded r;
+
+	bch2_replicas_entry_cached(&r.e, dev);
+
+	return update_replicas(c, k, &r.e, sectors, journal_seq, gc);
+}
+
+static int __replicas_deltas_realloc(struct btree_trans *trans, unsigned more,
+				     gfp_t gfp)
+{
+	struct replicas_delta_list *d = trans->fs_usage_deltas;
+	unsigned new_size = d ? (d->size + more) * 2 : 128;
+	unsigned alloc_size = sizeof(*d) + new_size;
+
+	WARN_ON_ONCE(alloc_size > REPLICAS_DELTA_LIST_MAX);
+
+	if (!d || d->used + more > d->size) {
+		d = krealloc(d, alloc_size, gfp|__GFP_ZERO);
+
+		if (unlikely(!d)) {
+			if (alloc_size > REPLICAS_DELTA_LIST_MAX)
+				return -ENOMEM;
+
+			d = mempool_alloc(&trans->c->replicas_delta_pool, gfp);
+			if (!d)
+				return -ENOMEM;
+
+			memset(d, 0, REPLICAS_DELTA_LIST_MAX);
+
+			if (trans->fs_usage_deltas)
+				memcpy(d, trans->fs_usage_deltas,
+				       trans->fs_usage_deltas->size + sizeof(*d));
+
+			new_size = REPLICAS_DELTA_LIST_MAX - sizeof(*d);
+			kfree(trans->fs_usage_deltas);
+		}
+
+		d->size = new_size;
+		trans->fs_usage_deltas = d;
+	}
+
+	return 0;
+}
+
+int bch2_replicas_deltas_realloc(struct btree_trans *trans, unsigned more)
+{
+	return allocate_dropping_locks_errcode(trans,
+				__replicas_deltas_realloc(trans, more, _gfp));
+}
+
+static inline int update_replicas_list(struct btree_trans *trans,
+					struct bch_replicas_entry *r,
+					s64 sectors)
+{
+	struct replicas_delta_list *d;
+	struct replicas_delta *n;
+	unsigned b;
+	int ret;
+
+	if (!sectors)
+		return 0;
+
+	b = replicas_entry_bytes(r) + 8;
+	ret = bch2_replicas_deltas_realloc(trans, b);
+	if (ret)
+		return ret;
+
+	d = trans->fs_usage_deltas;
+	n = (void *) d->d + d->used;
+	n->delta = sectors;
+	unsafe_memcpy((void *) n + offsetof(struct replicas_delta, r),
+		      r, replicas_entry_bytes(r),
+		      "flexible array member embedded in strcuct with padding");
+	bch2_replicas_entry_sort(&n->r);
+	d->used += b;
+	return 0;
+}
+
+static inline int update_cached_sectors_list(struct btree_trans *trans,
+					      unsigned dev, s64 sectors)
+{
+	struct bch_replicas_padded r;
+
+	bch2_replicas_entry_cached(&r.e, dev);
+
+	return update_replicas_list(trans, &r.e, sectors);
+}
+
+int bch2_mark_alloc(struct btree_trans *trans,
+		    enum btree_id btree, unsigned level,
+		    struct bkey_s_c old, struct bkey_s_c new,
+		    unsigned flags)
+{
+	bool gc = flags & BTREE_TRIGGER_GC;
+	u64 journal_seq = trans->journal_res.seq;
+	u64 bucket_journal_seq;
+	struct bch_fs *c = trans->c;
+	struct bch_alloc_v4 old_a_convert, new_a_convert;
+	const struct bch_alloc_v4 *old_a, *new_a;
+	struct bch_dev *ca;
+	int ret = 0;
+
+	/*
+	 * alloc btree is read in by bch2_alloc_read, not gc:
+	 */
+	if ((flags & BTREE_TRIGGER_GC) &&
+	    !(flags & BTREE_TRIGGER_BUCKET_INVALIDATE))
+		return 0;
+
+	if (bch2_trans_inconsistent_on(!bch2_dev_bucket_exists(c, new.k->p), trans,
+				       "alloc key for invalid device or bucket"))
+		return -EIO;
+
+	ca = bch_dev_bkey_exists(c, new.k->p.inode);
+
+	old_a = bch2_alloc_to_v4(old, &old_a_convert);
+	new_a = bch2_alloc_to_v4(new, &new_a_convert);
+
+	bucket_journal_seq = new_a->journal_seq;
+
+	if ((flags & BTREE_TRIGGER_INSERT) &&
+	    data_type_is_empty(old_a->data_type) !=
+	    data_type_is_empty(new_a->data_type) &&
+	    new.k->type == KEY_TYPE_alloc_v4) {
+		struct bch_alloc_v4 *v = (struct bch_alloc_v4 *) new.v;
+
+		EBUG_ON(!journal_seq);
+
+		/*
+		 * If the btree updates referring to a bucket weren't flushed
+		 * before the bucket became empty again, then the we don't have
+		 * to wait on a journal flush before we can reuse the bucket:
+		 */
+		v->journal_seq = bucket_journal_seq =
+			data_type_is_empty(new_a->data_type) &&
+			(journal_seq == v->journal_seq ||
+			 bch2_journal_noflush_seq(&c->journal, v->journal_seq))
+			? 0 : journal_seq;
+	}
+
+	if (!data_type_is_empty(old_a->data_type) &&
+	    data_type_is_empty(new_a->data_type) &&
+	    bucket_journal_seq) {
+		ret = bch2_set_bucket_needs_journal_commit(&c->buckets_waiting_for_journal,
+				c->journal.flushed_seq_ondisk,
+				new.k->p.inode, new.k->p.offset,
+				bucket_journal_seq);
+		if (ret) {
+			bch2_fs_fatal_error(c,
+				"error setting bucket_needs_journal_commit: %i", ret);
+			return ret;
+		}
+	}
+
+	percpu_down_read(&c->mark_lock);
+	if (!gc && new_a->gen != old_a->gen)
+		*bucket_gen(ca, new.k->p.offset) = new_a->gen;
+
+	bch2_dev_usage_update(c, ca, *old_a, *new_a, journal_seq, gc);
+
+	if (gc) {
+		struct bucket *g = gc_bucket(ca, new.k->p.offset);
+
+		bucket_lock(g);
+
+		g->gen_valid		= 1;
+		g->gen			= new_a->gen;
+		g->data_type		= new_a->data_type;
+		g->stripe		= new_a->stripe;
+		g->stripe_redundancy	= new_a->stripe_redundancy;
+		g->dirty_sectors	= new_a->dirty_sectors;
+		g->cached_sectors	= new_a->cached_sectors;
+
+		bucket_unlock(g);
+	}
+	percpu_up_read(&c->mark_lock);
+
+	/*
+	 * need to know if we're getting called from the invalidate path or
+	 * not:
+	 */
+
+	if ((flags & BTREE_TRIGGER_BUCKET_INVALIDATE) &&
+	    old_a->cached_sectors) {
+		ret = update_cached_sectors(c, new, ca->dev_idx,
+					    -((s64) old_a->cached_sectors),
+					    journal_seq, gc);
+		if (ret) {
+			bch2_fs_fatal_error(c, "%s(): no replicas entry while updating cached sectors",
+					    __func__);
+			return ret;
+		}
+	}
+
+	if (new_a->data_type == BCH_DATA_free &&
+	    (!new_a->journal_seq || new_a->journal_seq < c->journal.flushed_seq_ondisk))
+		closure_wake_up(&c->freelist_wait);
+
+	if (new_a->data_type == BCH_DATA_need_discard &&
+	    (!bucket_journal_seq || bucket_journal_seq < c->journal.flushed_seq_ondisk))
+		bch2_do_discards(c);
+
+	if (old_a->data_type != BCH_DATA_cached &&
+	    new_a->data_type == BCH_DATA_cached &&
+	    should_invalidate_buckets(ca, bch2_dev_usage_read(ca)))
+		bch2_do_invalidates(c);
+
+	if (new_a->data_type == BCH_DATA_need_gc_gens)
+		bch2_do_gc_gens(c);
+
+	return 0;
+}
+
+int bch2_mark_metadata_bucket(struct bch_fs *c, struct bch_dev *ca,
+			      size_t b, enum bch_data_type data_type,
+			      unsigned sectors, struct gc_pos pos,
+			      unsigned flags)
+{
+	struct bucket old, new, *g;
+	int ret = 0;
+
+	BUG_ON(!(flags & BTREE_TRIGGER_GC));
+	BUG_ON(data_type != BCH_DATA_sb &&
+	       data_type != BCH_DATA_journal);
+
+	/*
+	 * Backup superblock might be past the end of our normal usable space:
+	 */
+	if (b >= ca->mi.nbuckets)
+		return 0;
+
+	percpu_down_read(&c->mark_lock);
+	g = gc_bucket(ca, b);
+
+	bucket_lock(g);
+	old = *g;
+
+	if (bch2_fs_inconsistent_on(g->data_type &&
+			g->data_type != data_type, c,
+			"different types of data in same bucket: %s, %s",
+			bch2_data_types[g->data_type],
+			bch2_data_types[data_type])) {
+		ret = -EIO;
+		goto err;
+	}
+
+	if (bch2_fs_inconsistent_on((u64) g->dirty_sectors + sectors > ca->mi.bucket_size, c,
+			"bucket %u:%zu gen %u data type %s sector count overflow: %u + %u > bucket size",
+			ca->dev_idx, b, g->gen,
+			bch2_data_types[g->data_type ?: data_type],
+			g->dirty_sectors, sectors)) {
+		ret = -EIO;
+		goto err;
+	}
+
+
+	g->data_type = data_type;
+	g->dirty_sectors += sectors;
+	new = *g;
+err:
+	bucket_unlock(g);
+	if (!ret)
+		bch2_dev_usage_update_m(c, ca, old, new, 0, true);
+	percpu_up_read(&c->mark_lock);
+	return ret;
+}
+
+static int check_bucket_ref(struct btree_trans *trans,
+			    struct bkey_s_c k,
+			    const struct bch_extent_ptr *ptr,
+			    s64 sectors, enum bch_data_type ptr_data_type,
+			    u8 b_gen, u8 bucket_data_type,
+			    u32 dirty_sectors, u32 cached_sectors)
+{
+	struct bch_fs *c = trans->c;
+	struct bch_dev *ca = bch_dev_bkey_exists(c, ptr->dev);
+	size_t bucket_nr = PTR_BUCKET_NR(ca, ptr);
+	u32 bucket_sectors = !ptr->cached
+		? dirty_sectors
+		: cached_sectors;
+	struct printbuf buf = PRINTBUF;
+	int ret = 0;
+
+	if (bucket_data_type == BCH_DATA_cached)
+		bucket_data_type = BCH_DATA_user;
+
+	if ((bucket_data_type == BCH_DATA_stripe && ptr_data_type == BCH_DATA_user) ||
+	    (bucket_data_type == BCH_DATA_user   && ptr_data_type == BCH_DATA_stripe))
+		bucket_data_type = ptr_data_type = BCH_DATA_stripe;
+
+	if (gen_after(ptr->gen, b_gen)) {
+		bch2_fsck_err(c, FSCK_CAN_IGNORE|FSCK_NEED_FSCK,
+			      BCH_FSCK_ERR_ptr_gen_newer_than_bucket_gen,
+			"bucket %u:%zu gen %u data type %s: ptr gen %u newer than bucket gen\n"
+			"while marking %s",
+			ptr->dev, bucket_nr, b_gen,
+			bch2_data_types[bucket_data_type ?: ptr_data_type],
+			ptr->gen,
+			(bch2_bkey_val_to_text(&buf, c, k), buf.buf));
+		ret = -EIO;
+		goto err;
+	}
+
+	if (gen_cmp(b_gen, ptr->gen) > BUCKET_GC_GEN_MAX) {
+		bch2_fsck_err(c, FSCK_CAN_IGNORE|FSCK_NEED_FSCK,
+			      BCH_FSCK_ERR_ptr_too_stale,
+			"bucket %u:%zu gen %u data type %s: ptr gen %u too stale\n"
+			"while marking %s",
+			ptr->dev, bucket_nr, b_gen,
+			bch2_data_types[bucket_data_type ?: ptr_data_type],
+			ptr->gen,
+			(printbuf_reset(&buf),
+			 bch2_bkey_val_to_text(&buf, c, k), buf.buf));
+		ret = -EIO;
+		goto err;
+	}
+
+	if (b_gen != ptr->gen && !ptr->cached) {
+		bch2_fsck_err(c, FSCK_CAN_IGNORE|FSCK_NEED_FSCK,
+			      BCH_FSCK_ERR_stale_dirty_ptr,
+			"bucket %u:%zu gen %u (mem gen %u) data type %s: stale dirty ptr (gen %u)\n"
+			"while marking %s",
+			ptr->dev, bucket_nr, b_gen,
+			*bucket_gen(ca, bucket_nr),
+			bch2_data_types[bucket_data_type ?: ptr_data_type],
+			ptr->gen,
+			(printbuf_reset(&buf),
+			 bch2_bkey_val_to_text(&buf, c, k), buf.buf));
+		ret = -EIO;
+		goto err;
+	}
+
+	if (b_gen != ptr->gen) {
+		ret = 1;
+		goto out;
+	}
+
+	if (!data_type_is_empty(bucket_data_type) &&
+	    ptr_data_type &&
+	    bucket_data_type != ptr_data_type) {
+		bch2_fsck_err(c, FSCK_CAN_IGNORE|FSCK_NEED_FSCK,
+			      BCH_FSCK_ERR_ptr_bucket_data_type_mismatch,
+			"bucket %u:%zu gen %u different types of data in same bucket: %s, %s\n"
+			"while marking %s",
+			ptr->dev, bucket_nr, b_gen,
+			bch2_data_types[bucket_data_type],
+			bch2_data_types[ptr_data_type],
+			(printbuf_reset(&buf),
+			 bch2_bkey_val_to_text(&buf, c, k), buf.buf));
+		ret = -EIO;
+		goto err;
+	}
+
+	if ((u64) bucket_sectors + sectors > U32_MAX) {
+		bch2_fsck_err(c, FSCK_CAN_IGNORE|FSCK_NEED_FSCK,
+			      BCH_FSCK_ERR_bucket_sector_count_overflow,
+			"bucket %u:%zu gen %u data type %s sector count overflow: %u + %lli > U32_MAX\n"
+			"while marking %s",
+			ptr->dev, bucket_nr, b_gen,
+			bch2_data_types[bucket_data_type ?: ptr_data_type],
+			bucket_sectors, sectors,
+			(printbuf_reset(&buf),
+			 bch2_bkey_val_to_text(&buf, c, k), buf.buf));
+		ret = -EIO;
+		goto err;
+	}
+out:
+	printbuf_exit(&buf);
+	return ret;
+err:
+	bch2_dump_trans_updates(trans);
+	goto out;
+}
+
+static int mark_stripe_bucket(struct btree_trans *trans,
+			      struct bkey_s_c k,
+			      unsigned ptr_idx,
+			      unsigned flags)
+{
+	struct bch_fs *c = trans->c;
+	u64 journal_seq = trans->journal_res.seq;
+	const struct bch_stripe *s = bkey_s_c_to_stripe(k).v;
+	unsigned nr_data = s->nr_blocks - s->nr_redundant;
+	bool parity = ptr_idx >= nr_data;
+	enum bch_data_type data_type = parity ? BCH_DATA_parity : BCH_DATA_stripe;
+	s64 sectors = parity ? le16_to_cpu(s->sectors) : 0;
+	const struct bch_extent_ptr *ptr = s->ptrs + ptr_idx;
+	struct bch_dev *ca = bch_dev_bkey_exists(c, ptr->dev);
+	struct bucket old, new, *g;
+	struct printbuf buf = PRINTBUF;
+	int ret = 0;
+
+	BUG_ON(!(flags & BTREE_TRIGGER_GC));
+
+	/* * XXX doesn't handle deletion */
+
+	percpu_down_read(&c->mark_lock);
+	g = PTR_GC_BUCKET(ca, ptr);
+
+	if (g->dirty_sectors ||
+	    (g->stripe && g->stripe != k.k->p.offset)) {
+		bch2_fs_inconsistent(c,
+			      "bucket %u:%zu gen %u: multiple stripes using same bucket\n%s",
+			      ptr->dev, PTR_BUCKET_NR(ca, ptr), g->gen,
+			      (bch2_bkey_val_to_text(&buf, c, k), buf.buf));
+		ret = -EINVAL;
+		goto err;
+	}
+
+	bucket_lock(g);
+	old = *g;
+
+	ret = check_bucket_ref(trans, k, ptr, sectors, data_type,
+			       g->gen, g->data_type,
+			       g->dirty_sectors, g->cached_sectors);
+	if (ret)
+		goto err;
+
+	g->data_type = data_type;
+	g->dirty_sectors += sectors;
+
+	g->stripe		= k.k->p.offset;
+	g->stripe_redundancy	= s->nr_redundant;
+	new = *g;
+err:
+	bucket_unlock(g);
+	if (!ret)
+		bch2_dev_usage_update_m(c, ca, old, new, journal_seq, true);
+	percpu_up_read(&c->mark_lock);
+	printbuf_exit(&buf);
+	return ret;
+}
+
+static int __mark_pointer(struct btree_trans *trans,
+			  struct bkey_s_c k,
+			  const struct bch_extent_ptr *ptr,
+			  s64 sectors, enum bch_data_type ptr_data_type,
+			  u8 bucket_gen, u8 *bucket_data_type,
+			  u32 *dirty_sectors, u32 *cached_sectors)
+{
+	u32 *dst_sectors = !ptr->cached
+		? dirty_sectors
+		: cached_sectors;
+	int ret = check_bucket_ref(trans, k, ptr, sectors, ptr_data_type,
+				   bucket_gen, *bucket_data_type,
+				   *dirty_sectors, *cached_sectors);
+
+	if (ret)
+		return ret;
+
+	*dst_sectors += sectors;
+
+	if (!*dirty_sectors && !*cached_sectors)
+		*bucket_data_type = 0;
+	else if (*bucket_data_type != BCH_DATA_stripe)
+		*bucket_data_type = ptr_data_type;
+
+	return 0;
+}
+
+static int bch2_mark_pointer(struct btree_trans *trans,
+			     enum btree_id btree_id, unsigned level,
+			     struct bkey_s_c k,
+			     struct extent_ptr_decoded p,
+			     s64 sectors,
+			     unsigned flags)
+{
+	u64 journal_seq = trans->journal_res.seq;
+	struct bch_fs *c = trans->c;
+	struct bch_dev *ca = bch_dev_bkey_exists(c, p.ptr.dev);
+	struct bucket old, new, *g;
+	enum bch_data_type data_type = bkey_ptr_data_type(btree_id, level, k, p);
+	u8 bucket_data_type;
+	int ret = 0;
+
+	BUG_ON(!(flags & BTREE_TRIGGER_GC));
+
+	percpu_down_read(&c->mark_lock);
+	g = PTR_GC_BUCKET(ca, &p.ptr);
+	bucket_lock(g);
+	old = *g;
+
+	bucket_data_type = g->data_type;
+	ret = __mark_pointer(trans, k, &p.ptr, sectors,
+			     data_type, g->gen,
+			     &bucket_data_type,
+			     &g->dirty_sectors,
+			     &g->cached_sectors);
+	if (!ret)
+		g->data_type = bucket_data_type;
+
+	new = *g;
+	bucket_unlock(g);
+	if (!ret)
+		bch2_dev_usage_update_m(c, ca, old, new, journal_seq, true);
+	percpu_up_read(&c->mark_lock);
+
+	return ret;
+}
+
+static int bch2_mark_stripe_ptr(struct btree_trans *trans,
+				struct bkey_s_c k,
+				struct bch_extent_stripe_ptr p,
+				enum bch_data_type data_type,
+				s64 sectors,
+				unsigned flags)
+{
+	struct bch_fs *c = trans->c;
+	struct bch_replicas_padded r;
+	struct gc_stripe *m;
+
+	BUG_ON(!(flags & BTREE_TRIGGER_GC));
+
+	m = genradix_ptr_alloc(&c->gc_stripes, p.idx, GFP_KERNEL);
+	if (!m) {
+		bch_err(c, "error allocating memory for gc_stripes, idx %llu",
+			(u64) p.idx);
+		return -BCH_ERR_ENOMEM_mark_stripe_ptr;
+	}
+
+	mutex_lock(&c->ec_stripes_heap_lock);
+
+	if (!m || !m->alive) {
+		mutex_unlock(&c->ec_stripes_heap_lock);
+		bch_err_ratelimited(c, "pointer to nonexistent stripe %llu",
+				    (u64) p.idx);
+		bch2_inconsistent_error(c);
+		return -EIO;
+	}
+
+	m->block_sectors[p.block] += sectors;
+
+	r = m->r;
+	mutex_unlock(&c->ec_stripes_heap_lock);
+
+	r.e.data_type = data_type;
+	update_replicas(c, k, &r.e, sectors, trans->journal_res.seq, true);
+
+	return 0;
+}
+
+static int __mark_extent(struct btree_trans *trans,
+			 enum btree_id btree_id, unsigned level,
+			 struct bkey_s_c k, unsigned flags)
+{
+	u64 journal_seq = trans->journal_res.seq;
+	struct bch_fs *c = trans->c;
+	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
+	const union bch_extent_entry *entry;
+	struct extent_ptr_decoded p;
+	struct bch_replicas_padded r;
+	enum bch_data_type data_type = bkey_is_btree_ptr(k.k)
+		? BCH_DATA_btree
+		: BCH_DATA_user;
+	s64 sectors = bkey_is_btree_ptr(k.k)
+		? btree_sectors(c)
+		: k.k->size;
+	s64 dirty_sectors = 0;
+	bool stale;
+	int ret;
+
+	BUG_ON(!(flags & BTREE_TRIGGER_GC));
+
+	r.e.data_type	= data_type;
+	r.e.nr_devs	= 0;
+	r.e.nr_required	= 1;
+
+	bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
+		s64 disk_sectors = ptr_disk_sectors(sectors, p);
+
+		if (flags & BTREE_TRIGGER_OVERWRITE)
+			disk_sectors = -disk_sectors;
+
+		ret = bch2_mark_pointer(trans, btree_id, level, k, p, disk_sectors, flags);
+		if (ret < 0)
+			return ret;
+
+		stale = ret > 0;
+
+		if (p.ptr.cached) {
+			if (!stale) {
+				ret = update_cached_sectors(c, k, p.ptr.dev,
+						disk_sectors, journal_seq, true);
+				if (ret) {
+					bch2_fs_fatal_error(c, "%s(): no replicas entry while updating cached sectors",
+							    __func__);
+					return ret;
+				}
+			}
+		} else if (!p.has_ec) {
+			dirty_sectors	       += disk_sectors;
+			r.e.devs[r.e.nr_devs++]	= p.ptr.dev;
+		} else {
+			ret = bch2_mark_stripe_ptr(trans, k, p.ec, data_type,
+					disk_sectors, flags);
+			if (ret)
+				return ret;
+
+			/*
+			 * There may be other dirty pointers in this extent, but
+			 * if so they're not required for mounting if we have an
+			 * erasure coded pointer in this extent:
+			 */
+			r.e.nr_required = 0;
+		}
+	}
+
+	if (r.e.nr_devs) {
+		ret = update_replicas(c, k, &r.e, dirty_sectors, journal_seq, true);
+		if (ret) {
+			struct printbuf buf = PRINTBUF;
+
+			bch2_bkey_val_to_text(&buf, c, k);
+			bch2_fs_fatal_error(c, "%s(): no replicas entry for %s", __func__, buf.buf);
+			printbuf_exit(&buf);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+int bch2_mark_extent(struct btree_trans *trans,
+		     enum btree_id btree_id, unsigned level,
+		     struct bkey_s_c old, struct bkey_s_c new,
+		     unsigned flags)
+{
+	return mem_trigger_run_overwrite_then_insert(__mark_extent, trans, btree_id, level, old, new, flags);
+}
+
+int bch2_mark_stripe(struct btree_trans *trans,
+		     enum btree_id btree_id, unsigned level,
+		     struct bkey_s_c old, struct bkey_s_c new,
+		     unsigned flags)
+{
+	bool gc = flags & BTREE_TRIGGER_GC;
+	u64 journal_seq = trans->journal_res.seq;
+	struct bch_fs *c = trans->c;
+	u64 idx = new.k->p.offset;
+	const struct bch_stripe *old_s = old.k->type == KEY_TYPE_stripe
+		? bkey_s_c_to_stripe(old).v : NULL;
+	const struct bch_stripe *new_s = new.k->type == KEY_TYPE_stripe
+		? bkey_s_c_to_stripe(new).v : NULL;
+	unsigned i;
+	int ret;
+
+	BUG_ON(gc && old_s);
+
+	if (!gc) {
+		struct stripe *m = genradix_ptr(&c->stripes, idx);
+
+		if (!m) {
+			struct printbuf buf1 = PRINTBUF;
+			struct printbuf buf2 = PRINTBUF;
+
+			bch2_bkey_val_to_text(&buf1, c, old);
+			bch2_bkey_val_to_text(&buf2, c, new);
+			bch_err_ratelimited(c, "error marking nonexistent stripe %llu while marking\n"
+					    "old %s\n"
+					    "new %s", idx, buf1.buf, buf2.buf);
+			printbuf_exit(&buf2);
+			printbuf_exit(&buf1);
+			bch2_inconsistent_error(c);
+			return -1;
+		}
+
+		if (!new_s) {
+			bch2_stripes_heap_del(c, m, idx);
+
+			memset(m, 0, sizeof(*m));
+		} else {
+			m->sectors	= le16_to_cpu(new_s->sectors);
+			m->algorithm	= new_s->algorithm;
+			m->nr_blocks	= new_s->nr_blocks;
+			m->nr_redundant	= new_s->nr_redundant;
+			m->blocks_nonempty = 0;
+
+			for (i = 0; i < new_s->nr_blocks; i++)
+				m->blocks_nonempty += !!stripe_blockcount_get(new_s, i);
+
+			if (!old_s)
+				bch2_stripes_heap_insert(c, m, idx);
+			else
+				bch2_stripes_heap_update(c, m, idx);
+		}
+	} else {
+		struct gc_stripe *m =
+			genradix_ptr_alloc(&c->gc_stripes, idx, GFP_KERNEL);
+
+		if (!m) {
+			bch_err(c, "error allocating memory for gc_stripes, idx %llu",
+				idx);
+			return -BCH_ERR_ENOMEM_mark_stripe;
+		}
+		/*
+		 * This will be wrong when we bring back runtime gc: we should
+		 * be unmarking the old key and then marking the new key
+		 */
+		m->alive	= true;
+		m->sectors	= le16_to_cpu(new_s->sectors);
+		m->nr_blocks	= new_s->nr_blocks;
+		m->nr_redundant	= new_s->nr_redundant;
+
+		for (i = 0; i < new_s->nr_blocks; i++)
+			m->ptrs[i] = new_s->ptrs[i];
+
+		bch2_bkey_to_replicas(&m->r.e, new);
+
+		/*
+		 * gc recalculates this field from stripe ptr
+		 * references:
+		 */
+		memset(m->block_sectors, 0, sizeof(m->block_sectors));
+
+		for (i = 0; i < new_s->nr_blocks; i++) {
+			ret = mark_stripe_bucket(trans, new, i, flags);
+			if (ret)
+				return ret;
+		}
+
+		ret = update_replicas(c, new, &m->r.e,
+				      ((s64) m->sectors * m->nr_redundant),
+				      journal_seq, gc);
+		if (ret) {
+			struct printbuf buf = PRINTBUF;
+
+			bch2_bkey_val_to_text(&buf, c, new);
+			bch2_fs_fatal_error(c, "no replicas entry for %s", buf.buf);
+			printbuf_exit(&buf);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int __mark_reservation(struct btree_trans *trans,
+			      enum btree_id btree_id, unsigned level,
+			      struct bkey_s_c k, unsigned flags)
+{
+	struct bch_fs *c = trans->c;
+	struct bch_fs_usage *fs_usage;
+	unsigned replicas = bkey_s_c_to_reservation(k).v->nr_replicas;
+	s64 sectors = (s64) k.k->size;
+
+	BUG_ON(!(flags & BTREE_TRIGGER_GC));
+
+	if (flags & BTREE_TRIGGER_OVERWRITE)
+		sectors = -sectors;
+	sectors *= replicas;
+
+	percpu_down_read(&c->mark_lock);
+	preempt_disable();
+
+	fs_usage = fs_usage_ptr(c, trans->journal_res.seq, flags & BTREE_TRIGGER_GC);
+	replicas = clamp_t(unsigned, replicas, 1,
+			   ARRAY_SIZE(fs_usage->persistent_reserved));
+
+	fs_usage->reserved				+= sectors;
+	fs_usage->persistent_reserved[replicas - 1]	+= sectors;
+
+	preempt_enable();
+	percpu_up_read(&c->mark_lock);
+
+	return 0;
+}
+
+int bch2_mark_reservation(struct btree_trans *trans,
+			  enum btree_id btree_id, unsigned level,
+			  struct bkey_s_c old, struct bkey_s_c new,
+			  unsigned flags)
+{
+	return mem_trigger_run_overwrite_then_insert(__mark_reservation, trans, btree_id, level, old, new, flags);
+}
+
+static s64 __bch2_mark_reflink_p(struct btree_trans *trans,
+				 struct bkey_s_c_reflink_p p,
+				 u64 start, u64 end,
+				 u64 *idx, unsigned flags, size_t r_idx)
+{
+	struct bch_fs *c = trans->c;
+	struct reflink_gc *r;
+	int add = !(flags & BTREE_TRIGGER_OVERWRITE) ? 1 : -1;
+	u64 next_idx = end;
+	s64 ret = 0;
+	struct printbuf buf = PRINTBUF;
+
+	if (r_idx >= c->reflink_gc_nr)
+		goto not_found;
+
+	r = genradix_ptr(&c->reflink_gc_table, r_idx);
+	next_idx = min(next_idx, r->offset - r->size);
+	if (*idx < next_idx)
+		goto not_found;
+
+	BUG_ON((s64) r->refcount + add < 0);
+
+	r->refcount += add;
+	*idx = r->offset;
+	return 0;
+not_found:
+	if (fsck_err(c, reflink_p_to_missing_reflink_v,
+		     "pointer to missing indirect extent\n"
+		     "  %s\n"
+		     "  missing range %llu-%llu",
+		     (bch2_bkey_val_to_text(&buf, c, p.s_c), buf.buf),
+		     *idx, next_idx)) {
+		struct bkey_i_error *new;
+
+		new = bch2_trans_kmalloc(trans, sizeof(*new));
+		ret = PTR_ERR_OR_ZERO(new);
+		if (ret)
+			goto err;
+
+		bkey_init(&new->k);
+		new->k.type	= KEY_TYPE_error;
+		new->k.p		= bkey_start_pos(p.k);
+		new->k.p.offset += *idx - start;
+		bch2_key_resize(&new->k, next_idx - *idx);
+		ret = bch2_btree_insert_trans(trans, BTREE_ID_extents, &new->k_i,
+					  BTREE_TRIGGER_NORUN);
+	}
+
+	*idx = next_idx;
+err:
+fsck_err:
+	printbuf_exit(&buf);
+	return ret;
+}
+
+static int __mark_reflink_p(struct btree_trans *trans,
+			    enum btree_id btree_id, unsigned level,
+			    struct bkey_s_c k, unsigned flags)
+{
+	struct bch_fs *c = trans->c;
+	struct bkey_s_c_reflink_p p = bkey_s_c_to_reflink_p(k);
+	struct reflink_gc *ref;
+	size_t l, r, m;
+	u64 idx = le64_to_cpu(p.v->idx), start = idx;
+	u64 end = le64_to_cpu(p.v->idx) + p.k->size;
+	int ret = 0;
+
+	BUG_ON(!(flags & BTREE_TRIGGER_GC));
+
+	if (c->sb.version_upgrade_complete >= bcachefs_metadata_version_reflink_p_fix) {
+		idx -= le32_to_cpu(p.v->front_pad);
+		end += le32_to_cpu(p.v->back_pad);
+	}
+
+	l = 0;
+	r = c->reflink_gc_nr;
+	while (l < r) {
+		m = l + (r - l) / 2;
+
+		ref = genradix_ptr(&c->reflink_gc_table, m);
+		if (ref->offset <= idx)
+			l = m + 1;
+		else
+			r = m;
+	}
+
+	while (idx < end && !ret)
+		ret = __bch2_mark_reflink_p(trans, p, start, end,
+					    &idx, flags, l++);
+
+	return ret;
+}
+
+int bch2_mark_reflink_p(struct btree_trans *trans,
+			enum btree_id btree_id, unsigned level,
+			struct bkey_s_c old, struct bkey_s_c new,
+			unsigned flags)
+{
+	return mem_trigger_run_overwrite_then_insert(__mark_reflink_p, trans, btree_id, level, old, new, flags);
+}
+
+void bch2_trans_fs_usage_revert(struct btree_trans *trans,
+				struct replicas_delta_list *deltas)
+{
+	struct bch_fs *c = trans->c;
+	struct bch_fs_usage *dst;
+	struct replicas_delta *d, *top = (void *) deltas->d + deltas->used;
+	s64 added = 0;
+	unsigned i;
+
+	percpu_down_read(&c->mark_lock);
+	preempt_disable();
+	dst = fs_usage_ptr(c, trans->journal_res.seq, false);
+
+	/* revert changes: */
+	for (d = deltas->d; d != top; d = replicas_delta_next(d)) {
+		switch (d->r.data_type) {
+		case BCH_DATA_btree:
+		case BCH_DATA_user:
+		case BCH_DATA_parity:
+			added += d->delta;
+		}
+		BUG_ON(__update_replicas(c, dst, &d->r, -d->delta));
+	}
+
+	dst->nr_inodes -= deltas->nr_inodes;
+
+	for (i = 0; i < BCH_REPLICAS_MAX; i++) {
+		added				-= deltas->persistent_reserved[i];
+		dst->reserved			-= deltas->persistent_reserved[i];
+		dst->persistent_reserved[i]	-= deltas->persistent_reserved[i];
+	}
+
+	if (added > 0) {
+		trans->disk_res->sectors += added;
+		this_cpu_add(*c->online_reserved, added);
+	}
+
+	preempt_enable();
+	percpu_up_read(&c->mark_lock);
+}
+
+int bch2_trans_fs_usage_apply(struct btree_trans *trans,
+			      struct replicas_delta_list *deltas)
+{
+	struct bch_fs *c = trans->c;
+	static int warned_disk_usage = 0;
+	bool warn = false;
+	u64 disk_res_sectors = trans->disk_res ? trans->disk_res->sectors : 0;
+	struct replicas_delta *d, *d2;
+	struct replicas_delta *top = (void *) deltas->d + deltas->used;
+	struct bch_fs_usage *dst;
+	s64 added = 0, should_not_have_added;
+	unsigned i;
+
+	percpu_down_read(&c->mark_lock);
+	preempt_disable();
+	dst = fs_usage_ptr(c, trans->journal_res.seq, false);
+
+	for (d = deltas->d; d != top; d = replicas_delta_next(d)) {
+		switch (d->r.data_type) {
+		case BCH_DATA_btree:
+		case BCH_DATA_user:
+		case BCH_DATA_parity:
+			added += d->delta;
+		}
+
+		if (__update_replicas(c, dst, &d->r, d->delta))
+			goto need_mark;
+	}
+
+	dst->nr_inodes += deltas->nr_inodes;
+
+	for (i = 0; i < BCH_REPLICAS_MAX; i++) {
+		added				+= deltas->persistent_reserved[i];
+		dst->reserved			+= deltas->persistent_reserved[i];
+		dst->persistent_reserved[i]	+= deltas->persistent_reserved[i];
+	}
+
+	/*
+	 * Not allowed to reduce sectors_available except by getting a
+	 * reservation:
+	 */
+	should_not_have_added = added - (s64) disk_res_sectors;
+	if (unlikely(should_not_have_added > 0)) {
+		u64 old, new, v = atomic64_read(&c->sectors_available);
+
+		do {
+			old = v;
+			new = max_t(s64, 0, old - should_not_have_added);
+		} while ((v = atomic64_cmpxchg(&c->sectors_available,
+					       old, new)) != old);
+
+		added -= should_not_have_added;
+		warn = true;
+	}
+
+	if (added > 0) {
+		trans->disk_res->sectors -= added;
+		this_cpu_sub(*c->online_reserved, added);
+	}
+
+	preempt_enable();
+	percpu_up_read(&c->mark_lock);
+
+	if (unlikely(warn) && !xchg(&warned_disk_usage, 1))
+		bch2_trans_inconsistent(trans,
+					"disk usage increased %lli more than %llu sectors reserved)",
+					should_not_have_added, disk_res_sectors);
+	return 0;
+need_mark:
+	/* revert changes: */
+	for (d2 = deltas->d; d2 != d; d2 = replicas_delta_next(d2))
+		BUG_ON(__update_replicas(c, dst, &d2->r, -d2->delta));
+
+	preempt_enable();
+	percpu_up_read(&c->mark_lock);
+	return -1;
+}
+
+/* trans_mark: */
+
+static inline int bch2_trans_mark_pointer(struct btree_trans *trans,
+				   enum btree_id btree_id, unsigned level,
+				   struct bkey_s_c k, struct extent_ptr_decoded p,
+				   unsigned flags)
+{
+	bool insert = !(flags & BTREE_TRIGGER_OVERWRITE);
+	struct btree_iter iter;
+	struct bkey_i_alloc_v4 *a;
+	struct bpos bucket;
+	struct bch_backpointer bp;
+	s64 sectors;
+	int ret;
+
+	bch2_extent_ptr_to_bp(trans->c, btree_id, level, k, p, &bucket, &bp);
+	sectors = bp.bucket_len;
+	if (!insert)
+		sectors = -sectors;
+
+	a = bch2_trans_start_alloc_update(trans, &iter, bucket);
+	if (IS_ERR(a))
+		return PTR_ERR(a);
+
+	ret = __mark_pointer(trans, k, &p.ptr, sectors, bp.data_type,
+			     a->v.gen, &a->v.data_type,
+			     &a->v.dirty_sectors, &a->v.cached_sectors) ?:
+		bch2_trans_update(trans, &iter, &a->k_i, 0);
+	bch2_trans_iter_exit(trans, &iter);
+
+	if (ret)
+		return ret;
+
+	if (!p.ptr.cached) {
+		ret = bch2_bucket_backpointer_mod(trans, bucket, bp, k, insert);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int bch2_trans_mark_stripe_ptr(struct btree_trans *trans,
+			struct extent_ptr_decoded p,
+			s64 sectors, enum bch_data_type data_type)
+{
+	struct btree_iter iter;
+	struct bkey_i_stripe *s;
+	struct bch_replicas_padded r;
+	int ret = 0;
+
+	s = bch2_bkey_get_mut_typed(trans, &iter,
+			BTREE_ID_stripes, POS(0, p.ec.idx),
+			BTREE_ITER_WITH_UPDATES, stripe);
+	ret = PTR_ERR_OR_ZERO(s);
+	if (unlikely(ret)) {
+		bch2_trans_inconsistent_on(bch2_err_matches(ret, ENOENT), trans,
+			"pointer to nonexistent stripe %llu",
+			(u64) p.ec.idx);
+		goto err;
+	}
+
+	if (!bch2_ptr_matches_stripe(&s->v, p)) {
+		bch2_trans_inconsistent(trans,
+			"stripe pointer doesn't match stripe %llu",
+			(u64) p.ec.idx);
+		ret = -EIO;
+		goto err;
+	}
+
+	stripe_blockcount_set(&s->v, p.ec.block,
+		stripe_blockcount_get(&s->v, p.ec.block) +
+		sectors);
+
+	bch2_bkey_to_replicas(&r.e, bkey_i_to_s_c(&s->k_i));
+	r.e.data_type = data_type;
+	ret = update_replicas_list(trans, &r.e, sectors);
+err:
+	bch2_trans_iter_exit(trans, &iter);
+	return ret;
+}
+
+static int __trans_mark_extent(struct btree_trans *trans,
+			       enum btree_id btree_id, unsigned level,
+			       struct bkey_s_c k, unsigned flags)
+{
+	struct bch_fs *c = trans->c;
+	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
+	const union bch_extent_entry *entry;
+	struct extent_ptr_decoded p;
+	struct bch_replicas_padded r;
+	enum bch_data_type data_type = bkey_is_btree_ptr(k.k)
+		? BCH_DATA_btree
+		: BCH_DATA_user;
+	s64 sectors = bkey_is_btree_ptr(k.k)
+		? btree_sectors(c)
+		: k.k->size;
+	s64 dirty_sectors = 0;
+	bool stale;
+	int ret = 0;
+
+	r.e.data_type	= data_type;
+	r.e.nr_devs	= 0;
+	r.e.nr_required	= 1;
+
+	bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
+		s64 disk_sectors = ptr_disk_sectors(sectors, p);
+
+		if (flags & BTREE_TRIGGER_OVERWRITE)
+			disk_sectors = -disk_sectors;
+
+		ret = bch2_trans_mark_pointer(trans, btree_id, level, k, p, flags);
+		if (ret < 0)
+			return ret;
+
+		stale = ret > 0;
+
+		if (p.ptr.cached) {
+			if (!stale) {
+				ret = update_cached_sectors_list(trans, p.ptr.dev,
+								 disk_sectors);
+				if (ret)
+					return ret;
+			}
+		} else if (!p.has_ec) {
+			dirty_sectors	       += disk_sectors;
+			r.e.devs[r.e.nr_devs++]	= p.ptr.dev;
+		} else {
+			ret = bch2_trans_mark_stripe_ptr(trans, p,
+					disk_sectors, data_type);
+			if (ret)
+				return ret;
+
+			r.e.nr_required = 0;
+		}
+	}
+
+	if (r.e.nr_devs)
+		ret = update_replicas_list(trans, &r.e, dirty_sectors);
+
+	return ret;
+}
+
+int bch2_trans_mark_extent(struct btree_trans *trans,
+			   enum btree_id btree_id, unsigned level,
+			   struct bkey_s_c old, struct bkey_i *new,
+			   unsigned flags)
+{
+	struct bch_fs *c = trans->c;
+	int mod = (int) bch2_bkey_needs_rebalance(c, bkey_i_to_s_c(new)) -
+		  (int) bch2_bkey_needs_rebalance(c, old);
+
+	if (mod) {
+		int ret = bch2_btree_bit_mod(trans, BTREE_ID_rebalance_work, new->k.p, mod > 0);
+		if (ret)
+			return ret;
+	}
+
+	return trigger_run_overwrite_then_insert(__trans_mark_extent, trans, btree_id, level, old, new, flags);
+}
+
+static int bch2_trans_mark_stripe_bucket(struct btree_trans *trans,
+					 struct bkey_s_c_stripe s,
+					 unsigned idx, bool deleting)
+{
+	struct bch_fs *c = trans->c;
+	const struct bch_extent_ptr *ptr = &s.v->ptrs[idx];
+	struct btree_iter iter;
+	struct bkey_i_alloc_v4 *a;
+	enum bch_data_type data_type = idx >= s.v->nr_blocks - s.v->nr_redundant
+		? BCH_DATA_parity : 0;
+	s64 sectors = data_type ? le16_to_cpu(s.v->sectors) : 0;
+	int ret = 0;
+
+	if (deleting)
+		sectors = -sectors;
+
+	a = bch2_trans_start_alloc_update(trans, &iter, PTR_BUCKET_POS(c, ptr));
+	if (IS_ERR(a))
+		return PTR_ERR(a);
+
+	ret = check_bucket_ref(trans, s.s_c, ptr, sectors, data_type,
+			       a->v.gen, a->v.data_type,
+			       a->v.dirty_sectors, a->v.cached_sectors);
+	if (ret)
+		goto err;
+
+	if (!deleting) {
+		if (bch2_trans_inconsistent_on(a->v.stripe ||
+					       a->v.stripe_redundancy, trans,
+				"bucket %llu:%llu gen %u data type %s dirty_sectors %u: multiple stripes using same bucket (%u, %llu)",
+				iter.pos.inode, iter.pos.offset, a->v.gen,
+				bch2_data_types[a->v.data_type],
+				a->v.dirty_sectors,
+				a->v.stripe, s.k->p.offset)) {
+			ret = -EIO;
+			goto err;
+		}
+
+		if (bch2_trans_inconsistent_on(data_type && a->v.dirty_sectors, trans,
+				"bucket %llu:%llu gen %u data type %s dirty_sectors %u: data already in stripe bucket %llu",
+				iter.pos.inode, iter.pos.offset, a->v.gen,
+				bch2_data_types[a->v.data_type],
+				a->v.dirty_sectors,
+				s.k->p.offset)) {
+			ret = -EIO;
+			goto err;
+		}
+
+		a->v.stripe		= s.k->p.offset;
+		a->v.stripe_redundancy	= s.v->nr_redundant;
+		a->v.data_type		= BCH_DATA_stripe;
+	} else {
+		if (bch2_trans_inconsistent_on(a->v.stripe != s.k->p.offset ||
+					       a->v.stripe_redundancy != s.v->nr_redundant, trans,
+				"bucket %llu:%llu gen %u: not marked as stripe when deleting stripe %llu (got %u)",
+				iter.pos.inode, iter.pos.offset, a->v.gen,
+				s.k->p.offset, a->v.stripe)) {
+			ret = -EIO;
+			goto err;
+		}
+
+		a->v.stripe		= 0;
+		a->v.stripe_redundancy	= 0;
+		a->v.data_type		= alloc_data_type(a->v, BCH_DATA_user);
+	}
+
+	a->v.dirty_sectors += sectors;
+	if (data_type)
+		a->v.data_type = !deleting ? data_type : 0;
+
+	ret = bch2_trans_update(trans, &iter, &a->k_i, 0);
+	if (ret)
+		goto err;
+err:
+	bch2_trans_iter_exit(trans, &iter);
+	return ret;
+}
+
+int bch2_trans_mark_stripe(struct btree_trans *trans,
+			   enum btree_id btree_id, unsigned level,
+			   struct bkey_s_c old, struct bkey_i *new,
+			   unsigned flags)
+{
+	const struct bch_stripe *old_s = NULL;
+	struct bch_stripe *new_s = NULL;
+	struct bch_replicas_padded r;
+	unsigned i, nr_blocks;
+	int ret = 0;
+
+	if (old.k->type == KEY_TYPE_stripe)
+		old_s = bkey_s_c_to_stripe(old).v;
+	if (new->k.type == KEY_TYPE_stripe)
+		new_s = &bkey_i_to_stripe(new)->v;
+
+	/*
+	 * If the pointers aren't changing, we don't need to do anything:
+	 */
+	if (new_s && old_s &&
+	    new_s->nr_blocks	== old_s->nr_blocks &&
+	    new_s->nr_redundant	== old_s->nr_redundant &&
+	    !memcmp(old_s->ptrs, new_s->ptrs,
+		    new_s->nr_blocks * sizeof(struct bch_extent_ptr)))
+		return 0;
+
+	BUG_ON(new_s && old_s &&
+	       (new_s->nr_blocks	!= old_s->nr_blocks ||
+		new_s->nr_redundant	!= old_s->nr_redundant));
+
+	nr_blocks = new_s ? new_s->nr_blocks : old_s->nr_blocks;
+
+	if (new_s) {
+		s64 sectors = le16_to_cpu(new_s->sectors);
+
+		bch2_bkey_to_replicas(&r.e, bkey_i_to_s_c(new));
+		ret = update_replicas_list(trans, &r.e, sectors * new_s->nr_redundant);
+		if (ret)
+			return ret;
+	}
+
+	if (old_s) {
+		s64 sectors = -((s64) le16_to_cpu(old_s->sectors));
+
+		bch2_bkey_to_replicas(&r.e, old);
+		ret = update_replicas_list(trans, &r.e, sectors * old_s->nr_redundant);
+		if (ret)
+			return ret;
+	}
+
+	for (i = 0; i < nr_blocks; i++) {
+		if (new_s && old_s &&
+		    !memcmp(&new_s->ptrs[i],
+			    &old_s->ptrs[i],
+			    sizeof(new_s->ptrs[i])))
+			continue;
+
+		if (new_s) {
+			ret = bch2_trans_mark_stripe_bucket(trans,
+					bkey_i_to_s_c_stripe(new), i, false);
+			if (ret)
+				break;
+		}
+
+		if (old_s) {
+			ret = bch2_trans_mark_stripe_bucket(trans,
+					bkey_s_c_to_stripe(old), i, true);
+			if (ret)
+				break;
+		}
+	}
+
+	return ret;
+}
+
+static int __trans_mark_reservation(struct btree_trans *trans,
+				    enum btree_id btree_id, unsigned level,
+				    struct bkey_s_c k, unsigned flags)
+{
+	unsigned replicas = bkey_s_c_to_reservation(k).v->nr_replicas;
+	s64 sectors = (s64) k.k->size;
+	struct replicas_delta_list *d;
+	int ret;
+
+	if (flags & BTREE_TRIGGER_OVERWRITE)
+		sectors = -sectors;
+	sectors *= replicas;
+
+	ret = bch2_replicas_deltas_realloc(trans, 0);
+	if (ret)
+		return ret;
+
+	d = trans->fs_usage_deltas;
+	replicas = clamp_t(unsigned, replicas, 1,
+			   ARRAY_SIZE(d->persistent_reserved));
+
+	d->persistent_reserved[replicas - 1] += sectors;
+	return 0;
+}
+
+int bch2_trans_mark_reservation(struct btree_trans *trans,
+				enum btree_id btree_id, unsigned level,
+				struct bkey_s_c old,
+				struct bkey_i *new,
+				unsigned flags)
+{
+	return trigger_run_overwrite_then_insert(__trans_mark_reservation, trans, btree_id, level, old, new, flags);
+}
+
+static int trans_mark_reflink_p_segment(struct btree_trans *trans,
+			struct bkey_s_c_reflink_p p,
+			u64 *idx, unsigned flags)
+{
+	struct bch_fs *c = trans->c;
+	struct btree_iter iter;
+	struct bkey_i *k;
+	__le64 *refcount;
+	int add = !(flags & BTREE_TRIGGER_OVERWRITE) ? 1 : -1;
+	struct printbuf buf = PRINTBUF;
+	int ret;
+
+	k = bch2_bkey_get_mut_noupdate(trans, &iter,
+			BTREE_ID_reflink, POS(0, *idx),
+			BTREE_ITER_WITH_UPDATES);
+	ret = PTR_ERR_OR_ZERO(k);
+	if (ret)
+		goto err;
+
+	refcount = bkey_refcount(k);
+	if (!refcount) {
+		bch2_bkey_val_to_text(&buf, c, p.s_c);
+		bch2_trans_inconsistent(trans,
+			"nonexistent indirect extent at %llu while marking\n  %s",
+			*idx, buf.buf);
+		ret = -EIO;
+		goto err;
+	}
+
+	if (!*refcount && (flags & BTREE_TRIGGER_OVERWRITE)) {
+		bch2_bkey_val_to_text(&buf, c, p.s_c);
+		bch2_trans_inconsistent(trans,
+			"indirect extent refcount underflow at %llu while marking\n  %s",
+			*idx, buf.buf);
+		ret = -EIO;
+		goto err;
+	}
+
+	if (flags & BTREE_TRIGGER_INSERT) {
+		struct bch_reflink_p *v = (struct bch_reflink_p *) p.v;
+		u64 pad;
+
+		pad = max_t(s64, le32_to_cpu(v->front_pad),
+			    le64_to_cpu(v->idx) - bkey_start_offset(&k->k));
+		BUG_ON(pad > U32_MAX);
+		v->front_pad = cpu_to_le32(pad);
+
+		pad = max_t(s64, le32_to_cpu(v->back_pad),
+			    k->k.p.offset - p.k->size - le64_to_cpu(v->idx));
+		BUG_ON(pad > U32_MAX);
+		v->back_pad = cpu_to_le32(pad);
+	}
+
+	le64_add_cpu(refcount, add);
+
+	bch2_btree_iter_set_pos_to_extent_start(&iter);
+	ret = bch2_trans_update(trans, &iter, k, 0);
+	if (ret)
+		goto err;
+
+	*idx = k->k.p.offset;
+err:
+	bch2_trans_iter_exit(trans, &iter);
+	printbuf_exit(&buf);
+	return ret;
+}
+
+static int __trans_mark_reflink_p(struct btree_trans *trans,
+				enum btree_id btree_id, unsigned level,
+				struct bkey_s_c k, unsigned flags)
+{
+	struct bkey_s_c_reflink_p p = bkey_s_c_to_reflink_p(k);
+	u64 idx, end_idx;
+	int ret = 0;
+
+	idx	= le64_to_cpu(p.v->idx) - le32_to_cpu(p.v->front_pad);
+	end_idx = le64_to_cpu(p.v->idx) + p.k->size +
+		le32_to_cpu(p.v->back_pad);
+
+	while (idx < end_idx && !ret)
+		ret = trans_mark_reflink_p_segment(trans, p, &idx, flags);
+	return ret;
+}
+
+int bch2_trans_mark_reflink_p(struct btree_trans *trans,
+			      enum btree_id btree_id, unsigned level,
+			      struct bkey_s_c old,
+			      struct bkey_i *new,
+			      unsigned flags)
+{
+	if (flags & BTREE_TRIGGER_INSERT) {
+		struct bch_reflink_p *v = &bkey_i_to_reflink_p(new)->v;
+
+		v->front_pad = v->back_pad = 0;
+	}
+
+	return trigger_run_overwrite_then_insert(__trans_mark_reflink_p, trans, btree_id, level, old, new, flags);
+}
+
+static int __bch2_trans_mark_metadata_bucket(struct btree_trans *trans,
+				    struct bch_dev *ca, size_t b,
+				    enum bch_data_type type,
+				    unsigned sectors)
+{
+	struct bch_fs *c = trans->c;
+	struct btree_iter iter;
+	struct bkey_i_alloc_v4 *a;
+	int ret = 0;
+
+	/*
+	 * Backup superblock might be past the end of our normal usable space:
+	 */
+	if (b >= ca->mi.nbuckets)
+		return 0;
+
+	a = bch2_trans_start_alloc_update(trans, &iter, POS(ca->dev_idx, b));
+	if (IS_ERR(a))
+		return PTR_ERR(a);
+
+	if (a->v.data_type && type && a->v.data_type != type) {
+		bch2_fsck_err(c, FSCK_CAN_IGNORE|FSCK_NEED_FSCK,
+			      BCH_FSCK_ERR_bucket_metadata_type_mismatch,
+			"bucket %llu:%llu gen %u different types of data in same bucket: %s, %s\n"
+			"while marking %s",
+			iter.pos.inode, iter.pos.offset, a->v.gen,
+			bch2_data_types[a->v.data_type],
+			bch2_data_types[type],
+			bch2_data_types[type]);
+		ret = -EIO;
+		goto err;
+	}
+
+	if (a->v.data_type	!= type ||
+	    a->v.dirty_sectors	!= sectors) {
+		a->v.data_type		= type;
+		a->v.dirty_sectors	= sectors;
+		ret = bch2_trans_update(trans, &iter, &a->k_i, 0);
+	}
+err:
+	bch2_trans_iter_exit(trans, &iter);
+	return ret;
+}
+
+int bch2_trans_mark_metadata_bucket(struct btree_trans *trans,
+				    struct bch_dev *ca, size_t b,
+				    enum bch_data_type type,
+				    unsigned sectors)
+{
+	return commit_do(trans, NULL, NULL, 0,
+			__bch2_trans_mark_metadata_bucket(trans, ca, b, type, sectors));
+}
+
+static int bch2_trans_mark_metadata_sectors(struct btree_trans *trans,
+					    struct bch_dev *ca,
+					    u64 start, u64 end,
+					    enum bch_data_type type,
+					    u64 *bucket, unsigned *bucket_sectors)
+{
+	do {
+		u64 b = sector_to_bucket(ca, start);
+		unsigned sectors =
+			min_t(u64, bucket_to_sector(ca, b + 1), end) - start;
+
+		if (b != *bucket && *bucket_sectors) {
+			int ret = bch2_trans_mark_metadata_bucket(trans, ca, *bucket,
+								  type, *bucket_sectors);
+			if (ret)
+				return ret;
+
+			*bucket_sectors = 0;
+		}
+
+		*bucket		= b;
+		*bucket_sectors	+= sectors;
+		start += sectors;
+	} while (start < end);
+
+	return 0;
+}
+
+static int __bch2_trans_mark_dev_sb(struct btree_trans *trans,
+				    struct bch_dev *ca)
+{
+	struct bch_sb_layout *layout = &ca->disk_sb.sb->layout;
+	u64 bucket = 0;
+	unsigned i, bucket_sectors = 0;
+	int ret;
+
+	for (i = 0; i < layout->nr_superblocks; i++) {
+		u64 offset = le64_to_cpu(layout->sb_offset[i]);
+
+		if (offset == BCH_SB_SECTOR) {
+			ret = bch2_trans_mark_metadata_sectors(trans, ca,
+						0, BCH_SB_SECTOR,
+						BCH_DATA_sb, &bucket, &bucket_sectors);
+			if (ret)
+				return ret;
+		}
+
+		ret = bch2_trans_mark_metadata_sectors(trans, ca, offset,
+				      offset + (1 << layout->sb_max_size_bits),
+				      BCH_DATA_sb, &bucket, &bucket_sectors);
+		if (ret)
+			return ret;
+	}
+
+	if (bucket_sectors) {
+		ret = bch2_trans_mark_metadata_bucket(trans, ca,
+				bucket, BCH_DATA_sb, bucket_sectors);
+		if (ret)
+			return ret;
+	}
+
+	for (i = 0; i < ca->journal.nr; i++) {
+		ret = bch2_trans_mark_metadata_bucket(trans, ca,
+				ca->journal.buckets[i],
+				BCH_DATA_journal, ca->mi.bucket_size);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+int bch2_trans_mark_dev_sb(struct bch_fs *c, struct bch_dev *ca)
+{
+	int ret = bch2_trans_run(c, __bch2_trans_mark_dev_sb(trans, ca));
+
+	if (ret)
+		bch_err_fn(c, ret);
+	return ret;
+}
+
+int bch2_trans_mark_dev_sbs(struct bch_fs *c)
+{
+	struct bch_dev *ca;
+	unsigned i;
+
+	for_each_online_member(ca, c, i) {
+		int ret = bch2_trans_mark_dev_sb(c, ca);
+		if (ret) {
+			percpu_ref_put(&ca->ref);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+/* Disk reservations: */
+
+#define SECTORS_CACHE	1024
+
+int __bch2_disk_reservation_add(struct bch_fs *c, struct disk_reservation *res,
+			      u64 sectors, int flags)
+{
+	struct bch_fs_pcpu *pcpu;
+	u64 old, v, get;
+	s64 sectors_available;
+	int ret;
+
+	percpu_down_read(&c->mark_lock);
+	preempt_disable();
+	pcpu = this_cpu_ptr(c->pcpu);
+
+	if (sectors <= pcpu->sectors_available)
+		goto out;
+
+	v = atomic64_read(&c->sectors_available);
+	do {
+		old = v;
+		get = min((u64) sectors + SECTORS_CACHE, old);
+
+		if (get < sectors) {
+			preempt_enable();
+			goto recalculate;
+		}
+	} while ((v = atomic64_cmpxchg(&c->sectors_available,
+				       old, old - get)) != old);
+
+	pcpu->sectors_available		+= get;
+
+out:
+	pcpu->sectors_available		-= sectors;
+	this_cpu_add(*c->online_reserved, sectors);
+	res->sectors			+= sectors;
+
+	preempt_enable();
+	percpu_up_read(&c->mark_lock);
+	return 0;
+
+recalculate:
+	mutex_lock(&c->sectors_available_lock);
+
+	percpu_u64_set(&c->pcpu->sectors_available, 0);
+	sectors_available = avail_factor(__bch2_fs_usage_read_short(c).free);
+
+	if (sectors <= sectors_available ||
+	    (flags & BCH_DISK_RESERVATION_NOFAIL)) {
+		atomic64_set(&c->sectors_available,
+			     max_t(s64, 0, sectors_available - sectors));
+		this_cpu_add(*c->online_reserved, sectors);
+		res->sectors			+= sectors;
+		ret = 0;
+	} else {
+		atomic64_set(&c->sectors_available, sectors_available);
+		ret = -BCH_ERR_ENOSPC_disk_reservation;
+	}
+
+	mutex_unlock(&c->sectors_available_lock);
+	percpu_up_read(&c->mark_lock);
+
+	return ret;
+}
+
+/* Startup/shutdown: */
+
+static void bucket_gens_free_rcu(struct rcu_head *rcu)
+{
+	struct bucket_gens *buckets =
+		container_of(rcu, struct bucket_gens, rcu);
+
+	kvpfree(buckets, sizeof(*buckets) + buckets->nbuckets);
+}
+
+int bch2_dev_buckets_resize(struct bch_fs *c, struct bch_dev *ca, u64 nbuckets)
+{
+	struct bucket_gens *bucket_gens = NULL, *old_bucket_gens = NULL;
+	unsigned long *buckets_nouse = NULL;
+	bool resize = ca->bucket_gens != NULL;
+	int ret;
+
+	if (!(bucket_gens	= kvpmalloc(sizeof(struct bucket_gens) + nbuckets,
+					    GFP_KERNEL|__GFP_ZERO))) {
+		ret = -BCH_ERR_ENOMEM_bucket_gens;
+		goto err;
+	}
+
+	if ((c->opts.buckets_nouse &&
+	     !(buckets_nouse	= kvpmalloc(BITS_TO_LONGS(nbuckets) *
+					    sizeof(unsigned long),
+					    GFP_KERNEL|__GFP_ZERO)))) {
+		ret = -BCH_ERR_ENOMEM_buckets_nouse;
+		goto err;
+	}
+
+	bucket_gens->first_bucket = ca->mi.first_bucket;
+	bucket_gens->nbuckets	= nbuckets;
+
+	if (resize) {
+		down_write(&c->gc_lock);
+		down_write(&ca->bucket_lock);
+		percpu_down_write(&c->mark_lock);
+	}
+
+	old_bucket_gens = rcu_dereference_protected(ca->bucket_gens, 1);
+
+	if (resize) {
+		size_t n = min(bucket_gens->nbuckets, old_bucket_gens->nbuckets);
+
+		memcpy(bucket_gens->b,
+		       old_bucket_gens->b,
+		       n);
+		if (buckets_nouse)
+			memcpy(buckets_nouse,
+			       ca->buckets_nouse,
+			       BITS_TO_LONGS(n) * sizeof(unsigned long));
+	}
+
+	rcu_assign_pointer(ca->bucket_gens, bucket_gens);
+	bucket_gens	= old_bucket_gens;
+
+	swap(ca->buckets_nouse, buckets_nouse);
+
+	nbuckets = ca->mi.nbuckets;
+
+	if (resize) {
+		percpu_up_write(&c->mark_lock);
+		up_write(&ca->bucket_lock);
+		up_write(&c->gc_lock);
+	}
+
+	ret = 0;
+err:
+	kvpfree(buckets_nouse,
+		BITS_TO_LONGS(nbuckets) * sizeof(unsigned long));
+	if (bucket_gens)
+		call_rcu(&bucket_gens->rcu, bucket_gens_free_rcu);
+
+	return ret;
+}
+
+void bch2_dev_buckets_free(struct bch_dev *ca)
+{
+	unsigned i;
+
+	kvpfree(ca->buckets_nouse,
+		BITS_TO_LONGS(ca->mi.nbuckets) * sizeof(unsigned long));
+	kvpfree(rcu_dereference_protected(ca->bucket_gens, 1),
+		sizeof(struct bucket_gens) + ca->mi.nbuckets);
+
+	for (i = 0; i < ARRAY_SIZE(ca->usage); i++)
+		free_percpu(ca->usage[i]);
+	kfree(ca->usage_base);
+}
+
+int bch2_dev_buckets_alloc(struct bch_fs *c, struct bch_dev *ca)
+{
+	unsigned i;
+
+	ca->usage_base = kzalloc(sizeof(struct bch_dev_usage), GFP_KERNEL);
+	if (!ca->usage_base)
+		return -BCH_ERR_ENOMEM_usage_init;
+
+	for (i = 0; i < ARRAY_SIZE(ca->usage); i++) {
+		ca->usage[i] = alloc_percpu(struct bch_dev_usage);
+		if (!ca->usage[i])
+			return -BCH_ERR_ENOMEM_usage_init;
+	}
+
+	return bch2_dev_buckets_resize(c, ca, ca->mi.nbuckets);
+}