Merging upstream version 6.7.7.

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

1 files changed, 1065 insertions, 0 deletions

diff --git a/fs/bcachefs/replicas.c b/fs/bcachefs/replicas.c
new file mode 100644
index 0000000000..1c4a8f5c92
--- /dev/null
+++ b/fs/bcachefs/replicas.c
@@ -0,0 +1,1065 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "bcachefs.h"
+#include "buckets.h"
+#include "journal.h"
+#include "replicas.h"
+#include "super-io.h"
+
+static int bch2_cpu_replicas_to_sb_replicas(struct bch_fs *,
+					    struct bch_replicas_cpu *);
+
+/* Some (buggy!) compilers don't allow memcmp to be passed as a pointer */
+static int bch2_memcmp(const void *l, const void *r, size_t size)
+{
+	return memcmp(l, r, size);
+}
+
+/* Replicas tracking - in memory: */
+
+static void verify_replicas_entry(struct bch_replicas_entry *e)
+{
+#ifdef CONFIG_BCACHEFS_DEBUG
+	unsigned i;
+
+	BUG_ON(e->data_type >= BCH_DATA_NR);
+	BUG_ON(!e->nr_devs);
+	BUG_ON(e->nr_required > 1 &&
+	       e->nr_required >= e->nr_devs);
+
+	for (i = 0; i + 1 < e->nr_devs; i++)
+		BUG_ON(e->devs[i] >= e->devs[i + 1]);
+#endif
+}
+
+void bch2_replicas_entry_sort(struct bch_replicas_entry *e)
+{
+	bubble_sort(e->devs, e->nr_devs, u8_cmp);
+}
+
+static void bch2_cpu_replicas_sort(struct bch_replicas_cpu *r)
+{
+	eytzinger0_sort(r->entries, r->nr, r->entry_size, bch2_memcmp, NULL);
+}
+
+static void bch2_replicas_entry_v0_to_text(struct printbuf *out,
+					   struct bch_replicas_entry_v0 *e)
+{
+	unsigned i;
+
+	if (e->data_type < BCH_DATA_NR)
+		prt_printf(out, "%s", bch2_data_types[e->data_type]);
+	else
+		prt_printf(out, "(invalid data type %u)", e->data_type);
+
+	prt_printf(out, ": %u [", e->nr_devs);
+	for (i = 0; i < e->nr_devs; i++)
+		prt_printf(out, i ? " %u" : "%u", e->devs[i]);
+	prt_printf(out, "]");
+}
+
+void bch2_replicas_entry_to_text(struct printbuf *out,
+				 struct bch_replicas_entry *e)
+{
+	unsigned i;
+
+	if (e->data_type < BCH_DATA_NR)
+		prt_printf(out, "%s", bch2_data_types[e->data_type]);
+	else
+		prt_printf(out, "(invalid data type %u)", e->data_type);
+
+	prt_printf(out, ": %u/%u [", e->nr_required, e->nr_devs);
+	for (i = 0; i < e->nr_devs; i++)
+		prt_printf(out, i ? " %u" : "%u", e->devs[i]);
+	prt_printf(out, "]");
+}
+
+int bch2_replicas_entry_validate(struct bch_replicas_entry *r,
+				 struct bch_sb *sb,
+				 struct printbuf *err)
+{
+	if (!r->nr_devs) {
+		prt_printf(err, "no devices in entry ");
+		goto bad;
+	}
+
+	if (r->nr_required > 1 &&
+	    r->nr_required >= r->nr_devs) {
+		prt_printf(err, "bad nr_required in entry ");
+		goto bad;
+	}
+
+	for (unsigned i = 0; i < r->nr_devs; i++)
+		if (!bch2_dev_exists(sb, r->devs[i])) {
+			prt_printf(err, "invalid device %u in entry ", r->devs[i]);
+			goto bad;
+		}
+
+	return 0;
+bad:
+	bch2_replicas_entry_to_text(err, r);
+	return -BCH_ERR_invalid_replicas_entry;
+}
+
+void bch2_cpu_replicas_to_text(struct printbuf *out,
+			       struct bch_replicas_cpu *r)
+{
+	struct bch_replicas_entry *e;
+	bool first = true;
+
+	for_each_cpu_replicas_entry(r, e) {
+		if (!first)
+			prt_printf(out, " ");
+		first = false;
+
+		bch2_replicas_entry_to_text(out, e);
+	}
+}
+
+static void extent_to_replicas(struct bkey_s_c k,
+			       struct bch_replicas_entry *r)
+{
+	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
+	const union bch_extent_entry *entry;
+	struct extent_ptr_decoded p;
+
+	r->nr_required	= 1;
+
+	bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
+		if (p.ptr.cached)
+			continue;
+
+		if (!p.has_ec)
+			r->devs[r->nr_devs++] = p.ptr.dev;
+		else
+			r->nr_required = 0;
+	}
+}
+
+static void stripe_to_replicas(struct bkey_s_c k,
+			       struct bch_replicas_entry *r)
+{
+	struct bkey_s_c_stripe s = bkey_s_c_to_stripe(k);
+	const struct bch_extent_ptr *ptr;
+
+	r->nr_required	= s.v->nr_blocks - s.v->nr_redundant;
+
+	for (ptr = s.v->ptrs;
+	     ptr < s.v->ptrs + s.v->nr_blocks;
+	     ptr++)
+		r->devs[r->nr_devs++] = ptr->dev;
+}
+
+void bch2_bkey_to_replicas(struct bch_replicas_entry *e,
+			   struct bkey_s_c k)
+{
+	e->nr_devs = 0;
+
+	switch (k.k->type) {
+	case KEY_TYPE_btree_ptr:
+	case KEY_TYPE_btree_ptr_v2:
+		e->data_type = BCH_DATA_btree;
+		extent_to_replicas(k, e);
+		break;
+	case KEY_TYPE_extent:
+	case KEY_TYPE_reflink_v:
+		e->data_type = BCH_DATA_user;
+		extent_to_replicas(k, e);
+		break;
+	case KEY_TYPE_stripe:
+		e->data_type = BCH_DATA_parity;
+		stripe_to_replicas(k, e);
+		break;
+	}
+
+	bch2_replicas_entry_sort(e);
+}
+
+void bch2_devlist_to_replicas(struct bch_replicas_entry *e,
+			      enum bch_data_type data_type,
+			      struct bch_devs_list devs)
+{
+	unsigned i;
+
+	BUG_ON(!data_type ||
+	       data_type == BCH_DATA_sb ||
+	       data_type >= BCH_DATA_NR);
+
+	e->data_type	= data_type;
+	e->nr_devs	= 0;
+	e->nr_required	= 1;
+
+	for (i = 0; i < devs.nr; i++)
+		e->devs[e->nr_devs++] = devs.devs[i];
+
+	bch2_replicas_entry_sort(e);
+}
+
+static struct bch_replicas_cpu
+cpu_replicas_add_entry(struct bch_fs *c,
+		       struct bch_replicas_cpu *old,
+		       struct bch_replicas_entry *new_entry)
+{
+	unsigned i;
+	struct bch_replicas_cpu new = {
+		.nr		= old->nr + 1,
+		.entry_size	= max_t(unsigned, old->entry_size,
+					replicas_entry_bytes(new_entry)),
+	};
+
+	for (i = 0; i < new_entry->nr_devs; i++)
+		BUG_ON(!bch2_dev_exists2(c, new_entry->devs[i]));
+
+	BUG_ON(!new_entry->data_type);
+	verify_replicas_entry(new_entry);
+
+	new.entries = kcalloc(new.nr, new.entry_size, GFP_KERNEL);
+	if (!new.entries)
+		return new;
+
+	for (i = 0; i < old->nr; i++)
+		memcpy(cpu_replicas_entry(&new, i),
+		       cpu_replicas_entry(old, i),
+		       old->entry_size);
+
+	memcpy(cpu_replicas_entry(&new, old->nr),
+	       new_entry,
+	       replicas_entry_bytes(new_entry));
+
+	bch2_cpu_replicas_sort(&new);
+	return new;
+}
+
+static inline int __replicas_entry_idx(struct bch_replicas_cpu *r,
+				       struct bch_replicas_entry *search)
+{
+	int idx, entry_size = replicas_entry_bytes(search);
+
+	if (unlikely(entry_size > r->entry_size))
+		return -1;
+
+	verify_replicas_entry(search);
+
+#define entry_cmp(_l, _r, size)	memcmp(_l, _r, entry_size)
+	idx = eytzinger0_find(r->entries, r->nr, r->entry_size,
+			      entry_cmp, search);
+#undef entry_cmp
+
+	return idx < r->nr ? idx : -1;
+}
+
+int bch2_replicas_entry_idx(struct bch_fs *c,
+			    struct bch_replicas_entry *search)
+{
+	bch2_replicas_entry_sort(search);
+
+	return __replicas_entry_idx(&c->replicas, search);
+}
+
+static bool __replicas_has_entry(struct bch_replicas_cpu *r,
+				 struct bch_replicas_entry *search)
+{
+	return __replicas_entry_idx(r, search) >= 0;
+}
+
+bool bch2_replicas_marked(struct bch_fs *c,
+			  struct bch_replicas_entry *search)
+{
+	bool marked;
+
+	if (!search->nr_devs)
+		return true;
+
+	verify_replicas_entry(search);
+
+	percpu_down_read(&c->mark_lock);
+	marked = __replicas_has_entry(&c->replicas, search) &&
+		(likely((!c->replicas_gc.entries)) ||
+		 __replicas_has_entry(&c->replicas_gc, search));
+	percpu_up_read(&c->mark_lock);
+
+	return marked;
+}
+
+static void __replicas_table_update(struct bch_fs_usage *dst,
+				    struct bch_replicas_cpu *dst_r,
+				    struct bch_fs_usage *src,
+				    struct bch_replicas_cpu *src_r)
+{
+	int src_idx, dst_idx;
+
+	*dst = *src;
+
+	for (src_idx = 0; src_idx < src_r->nr; src_idx++) {
+		if (!src->replicas[src_idx])
+			continue;
+
+		dst_idx = __replicas_entry_idx(dst_r,
+				cpu_replicas_entry(src_r, src_idx));
+		BUG_ON(dst_idx < 0);
+
+		dst->replicas[dst_idx] = src->replicas[src_idx];
+	}
+}
+
+static void __replicas_table_update_pcpu(struct bch_fs_usage __percpu *dst_p,
+				    struct bch_replicas_cpu *dst_r,
+				    struct bch_fs_usage __percpu *src_p,
+				    struct bch_replicas_cpu *src_r)
+{
+	unsigned src_nr = sizeof(struct bch_fs_usage) / sizeof(u64) + src_r->nr;
+	struct bch_fs_usage *dst, *src = (void *)
+		bch2_acc_percpu_u64s((u64 __percpu *) src_p, src_nr);
+
+	preempt_disable();
+	dst = this_cpu_ptr(dst_p);
+	preempt_enable();
+
+	__replicas_table_update(dst, dst_r, src, src_r);
+}
+
+/*
+ * Resize filesystem accounting:
+ */
+static int replicas_table_update(struct bch_fs *c,
+				 struct bch_replicas_cpu *new_r)
+{
+	struct bch_fs_usage __percpu *new_usage[JOURNAL_BUF_NR];
+	struct bch_fs_usage_online *new_scratch = NULL;
+	struct bch_fs_usage __percpu *new_gc = NULL;
+	struct bch_fs_usage *new_base = NULL;
+	unsigned i, bytes = sizeof(struct bch_fs_usage) +
+		sizeof(u64) * new_r->nr;
+	unsigned scratch_bytes = sizeof(struct bch_fs_usage_online) +
+		sizeof(u64) * new_r->nr;
+	int ret = 0;
+
+	memset(new_usage, 0, sizeof(new_usage));
+
+	for (i = 0; i < ARRAY_SIZE(new_usage); i++)
+		if (!(new_usage[i] = __alloc_percpu_gfp(bytes,
+					sizeof(u64), GFP_KERNEL)))
+			goto err;
+
+	if (!(new_base = kzalloc(bytes, GFP_KERNEL)) ||
+	    !(new_scratch  = kmalloc(scratch_bytes, GFP_KERNEL)) ||
+	    (c->usage_gc &&
+	     !(new_gc = __alloc_percpu_gfp(bytes, sizeof(u64), GFP_KERNEL))))
+		goto err;
+
+	for (i = 0; i < ARRAY_SIZE(new_usage); i++)
+		if (c->usage[i])
+			__replicas_table_update_pcpu(new_usage[i], new_r,
+						     c->usage[i], &c->replicas);
+	if (c->usage_base)
+		__replicas_table_update(new_base,		new_r,
+					c->usage_base,		&c->replicas);
+	if (c->usage_gc)
+		__replicas_table_update_pcpu(new_gc,		new_r,
+					     c->usage_gc,	&c->replicas);
+
+	for (i = 0; i < ARRAY_SIZE(new_usage); i++)
+		swap(c->usage[i],	new_usage[i]);
+	swap(c->usage_base,	new_base);
+	swap(c->usage_scratch,	new_scratch);
+	swap(c->usage_gc,	new_gc);
+	swap(c->replicas,	*new_r);
+out:
+	free_percpu(new_gc);
+	kfree(new_scratch);
+	for (i = 0; i < ARRAY_SIZE(new_usage); i++)
+		free_percpu(new_usage[i]);
+	kfree(new_base);
+	return ret;
+err:
+	bch_err(c, "error updating replicas table: memory allocation failure");
+	ret = -BCH_ERR_ENOMEM_replicas_table;
+	goto out;
+}
+
+static unsigned reserve_journal_replicas(struct bch_fs *c,
+				     struct bch_replicas_cpu *r)
+{
+	struct bch_replicas_entry *e;
+	unsigned journal_res_u64s = 0;
+
+	/* nr_inodes: */
+	journal_res_u64s +=
+		DIV_ROUND_UP(sizeof(struct jset_entry_usage), sizeof(u64));
+
+	/* key_version: */
+	journal_res_u64s +=
+		DIV_ROUND_UP(sizeof(struct jset_entry_usage), sizeof(u64));
+
+	/* persistent_reserved: */
+	journal_res_u64s +=
+		DIV_ROUND_UP(sizeof(struct jset_entry_usage), sizeof(u64)) *
+		BCH_REPLICAS_MAX;
+
+	for_each_cpu_replicas_entry(r, e)
+		journal_res_u64s +=
+			DIV_ROUND_UP(sizeof(struct jset_entry_data_usage) +
+				     e->nr_devs, sizeof(u64));
+	return journal_res_u64s;
+}
+
+noinline
+static int bch2_mark_replicas_slowpath(struct bch_fs *c,
+				struct bch_replicas_entry *new_entry)
+{
+	struct bch_replicas_cpu new_r, new_gc;
+	int ret = 0;
+
+	verify_replicas_entry(new_entry);
+
+	memset(&new_r, 0, sizeof(new_r));
+	memset(&new_gc, 0, sizeof(new_gc));
+
+	mutex_lock(&c->sb_lock);
+
+	if (c->replicas_gc.entries &&
+	    !__replicas_has_entry(&c->replicas_gc, new_entry)) {
+		new_gc = cpu_replicas_add_entry(c, &c->replicas_gc, new_entry);
+		if (!new_gc.entries) {
+			ret = -BCH_ERR_ENOMEM_cpu_replicas;
+			goto err;
+		}
+	}
+
+	if (!__replicas_has_entry(&c->replicas, new_entry)) {
+		new_r = cpu_replicas_add_entry(c, &c->replicas, new_entry);
+		if (!new_r.entries) {
+			ret = -BCH_ERR_ENOMEM_cpu_replicas;
+			goto err;
+		}
+
+		ret = bch2_cpu_replicas_to_sb_replicas(c, &new_r);
+		if (ret)
+			goto err;
+
+		bch2_journal_entry_res_resize(&c->journal,
+				&c->replicas_journal_res,
+				reserve_journal_replicas(c, &new_r));
+	}
+
+	if (!new_r.entries &&
+	    !new_gc.entries)
+		goto out;
+
+	/* allocations done, now commit: */
+
+	if (new_r.entries)
+		bch2_write_super(c);
+
+	/* don't update in memory replicas until changes are persistent */
+	percpu_down_write(&c->mark_lock);
+	if (new_r.entries)
+		ret = replicas_table_update(c, &new_r);
+	if (new_gc.entries)
+		swap(new_gc, c->replicas_gc);
+	percpu_up_write(&c->mark_lock);
+out:
+	mutex_unlock(&c->sb_lock);
+
+	kfree(new_r.entries);
+	kfree(new_gc.entries);
+
+	return ret;
+err:
+	bch_err_msg(c, ret, "adding replicas entry");
+	goto out;
+}
+
+int bch2_mark_replicas(struct bch_fs *c, struct bch_replicas_entry *r)
+{
+	return likely(bch2_replicas_marked(c, r))
+		? 0 : bch2_mark_replicas_slowpath(c, r);
+}
+
+/* replicas delta list: */
+
+int bch2_replicas_delta_list_mark(struct bch_fs *c,
+				  struct replicas_delta_list *r)
+{
+	struct replicas_delta *d = r->d;
+	struct replicas_delta *top = (void *) r->d + r->used;
+	int ret = 0;
+
+	for (d = r->d; !ret && d != top; d = replicas_delta_next(d))
+		ret = bch2_mark_replicas(c, &d->r);
+	return ret;
+}
+
+/*
+ * Old replicas_gc mechanism: only used for journal replicas entries now, should
+ * die at some point:
+ */
+
+int bch2_replicas_gc_end(struct bch_fs *c, int ret)
+{
+	lockdep_assert_held(&c->replicas_gc_lock);
+
+	mutex_lock(&c->sb_lock);
+	percpu_down_write(&c->mark_lock);
+
+	ret =   ret ?:
+		bch2_cpu_replicas_to_sb_replicas(c, &c->replicas_gc) ?:
+		replicas_table_update(c, &c->replicas_gc);
+
+	kfree(c->replicas_gc.entries);
+	c->replicas_gc.entries = NULL;
+
+	percpu_up_write(&c->mark_lock);
+
+	if (!ret)
+		bch2_write_super(c);
+
+	mutex_unlock(&c->sb_lock);
+
+	return ret;
+}
+
+int bch2_replicas_gc_start(struct bch_fs *c, unsigned typemask)
+{
+	struct bch_replicas_entry *e;
+	unsigned i = 0;
+
+	lockdep_assert_held(&c->replicas_gc_lock);
+
+	mutex_lock(&c->sb_lock);
+	BUG_ON(c->replicas_gc.entries);
+
+	c->replicas_gc.nr		= 0;
+	c->replicas_gc.entry_size	= 0;
+
+	for_each_cpu_replicas_entry(&c->replicas, e)
+		if (!((1 << e->data_type) & typemask)) {
+			c->replicas_gc.nr++;
+			c->replicas_gc.entry_size =
+				max_t(unsigned, c->replicas_gc.entry_size,
+				      replicas_entry_bytes(e));
+		}
+
+	c->replicas_gc.entries = kcalloc(c->replicas_gc.nr,
+					 c->replicas_gc.entry_size,
+					 GFP_KERNEL);
+	if (!c->replicas_gc.entries) {
+		mutex_unlock(&c->sb_lock);
+		bch_err(c, "error allocating c->replicas_gc");
+		return -BCH_ERR_ENOMEM_replicas_gc;
+	}
+
+	for_each_cpu_replicas_entry(&c->replicas, e)
+		if (!((1 << e->data_type) & typemask))
+			memcpy(cpu_replicas_entry(&c->replicas_gc, i++),
+			       e, c->replicas_gc.entry_size);
+
+	bch2_cpu_replicas_sort(&c->replicas_gc);
+	mutex_unlock(&c->sb_lock);
+
+	return 0;
+}
+
+/*
+ * New much simpler mechanism for clearing out unneeded replicas entries - drop
+ * replicas entries that have 0 sectors used.
+ *
+ * However, we don't track sector counts for journal usage, so this doesn't drop
+ * any BCH_DATA_journal entries; the old bch2_replicas_gc_(start|end) mechanism
+ * is retained for that.
+ */
+int bch2_replicas_gc2(struct bch_fs *c)
+{
+	struct bch_replicas_cpu new = { 0 };
+	unsigned i, nr;
+	int ret = 0;
+
+	bch2_journal_meta(&c->journal);
+retry:
+	nr		= READ_ONCE(c->replicas.nr);
+	new.entry_size	= READ_ONCE(c->replicas.entry_size);
+	new.entries	= kcalloc(nr, new.entry_size, GFP_KERNEL);
+	if (!new.entries) {
+		bch_err(c, "error allocating c->replicas_gc");
+		return -BCH_ERR_ENOMEM_replicas_gc;
+	}
+
+	mutex_lock(&c->sb_lock);
+	percpu_down_write(&c->mark_lock);
+
+	if (nr			!= c->replicas.nr ||
+	    new.entry_size	!= c->replicas.entry_size) {
+		percpu_up_write(&c->mark_lock);
+		mutex_unlock(&c->sb_lock);
+		kfree(new.entries);
+		goto retry;
+	}
+
+	for (i = 0; i < c->replicas.nr; i++) {
+		struct bch_replicas_entry *e =
+			cpu_replicas_entry(&c->replicas, i);
+
+		if (e->data_type == BCH_DATA_journal ||
+		    c->usage_base->replicas[i] ||
+		    percpu_u64_get(&c->usage[0]->replicas[i]) ||
+		    percpu_u64_get(&c->usage[1]->replicas[i]) ||
+		    percpu_u64_get(&c->usage[2]->replicas[i]) ||
+		    percpu_u64_get(&c->usage[3]->replicas[i]))
+			memcpy(cpu_replicas_entry(&new, new.nr++),
+			       e, new.entry_size);
+	}
+
+	bch2_cpu_replicas_sort(&new);
+
+	ret =   bch2_cpu_replicas_to_sb_replicas(c, &new) ?:
+		replicas_table_update(c, &new);
+
+	kfree(new.entries);
+
+	percpu_up_write(&c->mark_lock);
+
+	if (!ret)
+		bch2_write_super(c);
+
+	mutex_unlock(&c->sb_lock);
+
+	return ret;
+}
+
+int bch2_replicas_set_usage(struct bch_fs *c,
+			    struct bch_replicas_entry *r,
+			    u64 sectors)
+{
+	int ret, idx = bch2_replicas_entry_idx(c, r);
+
+	if (idx < 0) {
+		struct bch_replicas_cpu n;
+
+		n = cpu_replicas_add_entry(c, &c->replicas, r);
+		if (!n.entries)
+			return -BCH_ERR_ENOMEM_cpu_replicas;
+
+		ret = replicas_table_update(c, &n);
+		if (ret)
+			return ret;
+
+		kfree(n.entries);
+
+		idx = bch2_replicas_entry_idx(c, r);
+		BUG_ON(ret < 0);
+	}
+
+	c->usage_base->replicas[idx] = sectors;
+
+	return 0;
+}
+
+/* Replicas tracking - superblock: */
+
+static int
+__bch2_sb_replicas_to_cpu_replicas(struct bch_sb_field_replicas *sb_r,
+				   struct bch_replicas_cpu *cpu_r)
+{
+	struct bch_replicas_entry *e, *dst;
+	unsigned nr = 0, entry_size = 0, idx = 0;
+
+	for_each_replicas_entry(sb_r, e) {
+		entry_size = max_t(unsigned, entry_size,
+				   replicas_entry_bytes(e));
+		nr++;
+	}
+
+	cpu_r->entries = kcalloc(nr, entry_size, GFP_KERNEL);
+	if (!cpu_r->entries)
+		return -BCH_ERR_ENOMEM_cpu_replicas;
+
+	cpu_r->nr		= nr;
+	cpu_r->entry_size	= entry_size;
+
+	for_each_replicas_entry(sb_r, e) {
+		dst = cpu_replicas_entry(cpu_r, idx++);
+		memcpy(dst, e, replicas_entry_bytes(e));
+		bch2_replicas_entry_sort(dst);
+	}
+
+	return 0;
+}
+
+static int
+__bch2_sb_replicas_v0_to_cpu_replicas(struct bch_sb_field_replicas_v0 *sb_r,
+				      struct bch_replicas_cpu *cpu_r)
+{
+	struct bch_replicas_entry_v0 *e;
+	unsigned nr = 0, entry_size = 0, idx = 0;
+
+	for_each_replicas_entry(sb_r, e) {
+		entry_size = max_t(unsigned, entry_size,
+				   replicas_entry_bytes(e));
+		nr++;
+	}
+
+	entry_size += sizeof(struct bch_replicas_entry) -
+		sizeof(struct bch_replicas_entry_v0);
+
+	cpu_r->entries = kcalloc(nr, entry_size, GFP_KERNEL);
+	if (!cpu_r->entries)
+		return -BCH_ERR_ENOMEM_cpu_replicas;
+
+	cpu_r->nr		= nr;
+	cpu_r->entry_size	= entry_size;
+
+	for_each_replicas_entry(sb_r, e) {
+		struct bch_replicas_entry *dst =
+			cpu_replicas_entry(cpu_r, idx++);
+
+		dst->data_type	= e->data_type;
+		dst->nr_devs	= e->nr_devs;
+		dst->nr_required = 1;
+		memcpy(dst->devs, e->devs, e->nr_devs);
+		bch2_replicas_entry_sort(dst);
+	}
+
+	return 0;
+}
+
+int bch2_sb_replicas_to_cpu_replicas(struct bch_fs *c)
+{
+	struct bch_sb_field_replicas *sb_v1;
+	struct bch_sb_field_replicas_v0 *sb_v0;
+	struct bch_replicas_cpu new_r = { 0, 0, NULL };
+	int ret = 0;
+
+	if ((sb_v1 = bch2_sb_field_get(c->disk_sb.sb, replicas)))
+		ret = __bch2_sb_replicas_to_cpu_replicas(sb_v1, &new_r);
+	else if ((sb_v0 = bch2_sb_field_get(c->disk_sb.sb, replicas_v0)))
+		ret = __bch2_sb_replicas_v0_to_cpu_replicas(sb_v0, &new_r);
+	if (ret)
+		return ret;
+
+	bch2_cpu_replicas_sort(&new_r);
+
+	percpu_down_write(&c->mark_lock);
+
+	ret = replicas_table_update(c, &new_r);
+	percpu_up_write(&c->mark_lock);
+
+	kfree(new_r.entries);
+
+	return 0;
+}
+
+static int bch2_cpu_replicas_to_sb_replicas_v0(struct bch_fs *c,
+					       struct bch_replicas_cpu *r)
+{
+	struct bch_sb_field_replicas_v0 *sb_r;
+	struct bch_replicas_entry_v0 *dst;
+	struct bch_replicas_entry *src;
+	size_t bytes;
+
+	bytes = sizeof(struct bch_sb_field_replicas);
+
+	for_each_cpu_replicas_entry(r, src)
+		bytes += replicas_entry_bytes(src) - 1;
+
+	sb_r = bch2_sb_field_resize(&c->disk_sb, replicas_v0,
+			DIV_ROUND_UP(bytes, sizeof(u64)));
+	if (!sb_r)
+		return -BCH_ERR_ENOSPC_sb_replicas;
+
+	bch2_sb_field_delete(&c->disk_sb, BCH_SB_FIELD_replicas);
+	sb_r = bch2_sb_field_get(c->disk_sb.sb, replicas_v0);
+
+	memset(&sb_r->entries, 0,
+	       vstruct_end(&sb_r->field) -
+	       (void *) &sb_r->entries);
+
+	dst = sb_r->entries;
+	for_each_cpu_replicas_entry(r, src) {
+		dst->data_type	= src->data_type;
+		dst->nr_devs	= src->nr_devs;
+		memcpy(dst->devs, src->devs, src->nr_devs);
+
+		dst = replicas_entry_next(dst);
+
+		BUG_ON((void *) dst > vstruct_end(&sb_r->field));
+	}
+
+	return 0;
+}
+
+static int bch2_cpu_replicas_to_sb_replicas(struct bch_fs *c,
+					    struct bch_replicas_cpu *r)
+{
+	struct bch_sb_field_replicas *sb_r;
+	struct bch_replicas_entry *dst, *src;
+	bool need_v1 = false;
+	size_t bytes;
+
+	bytes = sizeof(struct bch_sb_field_replicas);
+
+	for_each_cpu_replicas_entry(r, src) {
+		bytes += replicas_entry_bytes(src);
+		if (src->nr_required != 1)
+			need_v1 = true;
+	}
+
+	if (!need_v1)
+		return bch2_cpu_replicas_to_sb_replicas_v0(c, r);
+
+	sb_r = bch2_sb_field_resize(&c->disk_sb, replicas,
+			DIV_ROUND_UP(bytes, sizeof(u64)));
+	if (!sb_r)
+		return -BCH_ERR_ENOSPC_sb_replicas;
+
+	bch2_sb_field_delete(&c->disk_sb, BCH_SB_FIELD_replicas_v0);
+	sb_r = bch2_sb_field_get(c->disk_sb.sb, replicas);
+
+	memset(&sb_r->entries, 0,
+	       vstruct_end(&sb_r->field) -
+	       (void *) &sb_r->entries);
+
+	dst = sb_r->entries;
+	for_each_cpu_replicas_entry(r, src) {
+		memcpy(dst, src, replicas_entry_bytes(src));
+
+		dst = replicas_entry_next(dst);
+
+		BUG_ON((void *) dst > vstruct_end(&sb_r->field));
+	}
+
+	return 0;
+}
+
+static int bch2_cpu_replicas_validate(struct bch_replicas_cpu *cpu_r,
+				      struct bch_sb *sb,
+				      struct printbuf *err)
+{
+	unsigned i;
+
+	sort_cmp_size(cpu_r->entries,
+		      cpu_r->nr,
+		      cpu_r->entry_size,
+		      bch2_memcmp, NULL);
+
+	for (i = 0; i < cpu_r->nr; i++) {
+		struct bch_replicas_entry *e =
+			cpu_replicas_entry(cpu_r, i);
+
+		int ret = bch2_replicas_entry_validate(e, sb, err);
+		if (ret)
+			return ret;
+
+		if (i + 1 < cpu_r->nr) {
+			struct bch_replicas_entry *n =
+				cpu_replicas_entry(cpu_r, i + 1);
+
+			BUG_ON(memcmp(e, n, cpu_r->entry_size) > 0);
+
+			if (!memcmp(e, n, cpu_r->entry_size)) {
+				prt_printf(err, "duplicate replicas entry ");
+				bch2_replicas_entry_to_text(err, e);
+				return -BCH_ERR_invalid_sb_replicas;
+			}
+		}
+	}
+
+	return 0;
+}
+
+static int bch2_sb_replicas_validate(struct bch_sb *sb, struct bch_sb_field *f,
+				     struct printbuf *err)
+{
+	struct bch_sb_field_replicas *sb_r = field_to_type(f, replicas);
+	struct bch_replicas_cpu cpu_r;
+	int ret;
+
+	ret = __bch2_sb_replicas_to_cpu_replicas(sb_r, &cpu_r);
+	if (ret)
+		return ret;
+
+	ret = bch2_cpu_replicas_validate(&cpu_r, sb, err);
+	kfree(cpu_r.entries);
+	return ret;
+}
+
+static void bch2_sb_replicas_to_text(struct printbuf *out,
+				     struct bch_sb *sb,
+				     struct bch_sb_field *f)
+{
+	struct bch_sb_field_replicas *r = field_to_type(f, replicas);
+	struct bch_replicas_entry *e;
+	bool first = true;
+
+	for_each_replicas_entry(r, e) {
+		if (!first)
+			prt_printf(out, " ");
+		first = false;
+
+		bch2_replicas_entry_to_text(out, e);
+	}
+	prt_newline(out);
+}
+
+const struct bch_sb_field_ops bch_sb_field_ops_replicas = {
+	.validate	= bch2_sb_replicas_validate,
+	.to_text	= bch2_sb_replicas_to_text,
+};
+
+static int bch2_sb_replicas_v0_validate(struct bch_sb *sb, struct bch_sb_field *f,
+					struct printbuf *err)
+{
+	struct bch_sb_field_replicas_v0 *sb_r = field_to_type(f, replicas_v0);
+	struct bch_replicas_cpu cpu_r;
+	int ret;
+
+	ret = __bch2_sb_replicas_v0_to_cpu_replicas(sb_r, &cpu_r);
+	if (ret)
+		return ret;
+
+	ret = bch2_cpu_replicas_validate(&cpu_r, sb, err);
+	kfree(cpu_r.entries);
+	return ret;
+}
+
+static void bch2_sb_replicas_v0_to_text(struct printbuf *out,
+					struct bch_sb *sb,
+					struct bch_sb_field *f)
+{
+	struct bch_sb_field_replicas_v0 *sb_r = field_to_type(f, replicas_v0);
+	struct bch_replicas_entry_v0 *e;
+	bool first = true;
+
+	for_each_replicas_entry(sb_r, e) {
+		if (!first)
+			prt_printf(out, " ");
+		first = false;
+
+		bch2_replicas_entry_v0_to_text(out, e);
+	}
+	prt_newline(out);
+}
+
+const struct bch_sb_field_ops bch_sb_field_ops_replicas_v0 = {
+	.validate	= bch2_sb_replicas_v0_validate,
+	.to_text	= bch2_sb_replicas_v0_to_text,
+};
+
+/* Query replicas: */
+
+bool bch2_have_enough_devs(struct bch_fs *c, struct bch_devs_mask devs,
+			   unsigned flags, bool print)
+{
+	struct bch_replicas_entry *e;
+	bool ret = true;
+
+	percpu_down_read(&c->mark_lock);
+	for_each_cpu_replicas_entry(&c->replicas, e) {
+		unsigned i, nr_online = 0, nr_failed = 0, dflags = 0;
+		bool metadata = e->data_type < BCH_DATA_user;
+
+		if (e->data_type == BCH_DATA_cached)
+			continue;
+
+		for (i = 0; i < e->nr_devs; i++) {
+			struct bch_dev *ca = bch_dev_bkey_exists(c, e->devs[i]);
+
+			nr_online += test_bit(e->devs[i], devs.d);
+			nr_failed += ca->mi.state == BCH_MEMBER_STATE_failed;
+		}
+
+		if (nr_failed == e->nr_devs)
+			continue;
+
+		if (nr_online < e->nr_required)
+			dflags |= metadata
+				? BCH_FORCE_IF_METADATA_LOST
+				: BCH_FORCE_IF_DATA_LOST;
+
+		if (nr_online < e->nr_devs)
+			dflags |= metadata
+				? BCH_FORCE_IF_METADATA_DEGRADED
+				: BCH_FORCE_IF_DATA_DEGRADED;
+
+		if (dflags & ~flags) {
+			if (print) {
+				struct printbuf buf = PRINTBUF;
+
+				bch2_replicas_entry_to_text(&buf, e);
+				bch_err(c, "insufficient devices online (%u) for replicas entry %s",
+					nr_online, buf.buf);
+				printbuf_exit(&buf);
+			}
+			ret = false;
+			break;
+		}
+
+	}
+	percpu_up_read(&c->mark_lock);
+
+	return ret;
+}
+
+unsigned bch2_sb_dev_has_data(struct bch_sb *sb, unsigned dev)
+{
+	struct bch_sb_field_replicas *replicas;
+	struct bch_sb_field_replicas_v0 *replicas_v0;
+	unsigned i, data_has = 0;
+
+	replicas = bch2_sb_field_get(sb, replicas);
+	replicas_v0 = bch2_sb_field_get(sb, replicas_v0);
+
+	if (replicas) {
+		struct bch_replicas_entry *r;
+
+		for_each_replicas_entry(replicas, r)
+			for (i = 0; i < r->nr_devs; i++)
+				if (r->devs[i] == dev)
+					data_has |= 1 << r->data_type;
+	} else if (replicas_v0) {
+		struct bch_replicas_entry_v0 *r;
+
+		for_each_replicas_entry_v0(replicas_v0, r)
+			for (i = 0; i < r->nr_devs; i++)
+				if (r->devs[i] == dev)
+					data_has |= 1 << r->data_type;
+	}
+
+
+	return data_has;
+}
+
+unsigned bch2_dev_has_data(struct bch_fs *c, struct bch_dev *ca)
+{
+	unsigned ret;
+
+	mutex_lock(&c->sb_lock);
+	ret = bch2_sb_dev_has_data(c->disk_sb.sb, ca->dev_idx);
+	mutex_unlock(&c->sb_lock);
+
+	return ret;
+}
+
+void bch2_fs_replicas_exit(struct bch_fs *c)
+{
+	unsigned i;
+
+	kfree(c->usage_scratch);
+	for (i = 0; i < ARRAY_SIZE(c->usage); i++)
+		free_percpu(c->usage[i]);
+	kfree(c->usage_base);
+	kfree(c->replicas.entries);
+	kfree(c->replicas_gc.entries);
+
+	mempool_exit(&c->replicas_delta_pool);
+}
+
+int bch2_fs_replicas_init(struct bch_fs *c)
+{
+	bch2_journal_entry_res_resize(&c->journal,
+			&c->replicas_journal_res,
+			reserve_journal_replicas(c, &c->replicas));
+
+	return mempool_init_kmalloc_pool(&c->replicas_delta_pool, 1,
+					 REPLICAS_DELTA_LIST_MAX) ?:
+		replicas_table_update(c, &c->replicas);
+}