diff --git a/.bcachefs_revision b/.bcachefs_revision
index 5d86ae9c..ae0826de 100644
--- a/.bcachefs_revision
+++ b/.bcachefs_revision
@@ -1 +1 @@
-864591728963d416c49e502bfee56a283eda31a5
+f4b9a91fce7373d163343e5ca3a9b483d113706d
diff --git a/bch_bindgen/build.rs b/bch_bindgen/build.rs
index 4a3755a1..e2aeebb3 100644
--- a/bch_bindgen/build.rs
+++ b/bch_bindgen/build.rs
@@ -63,7 +63,6 @@ fn main() {
         .allowlist_function("printbuf.*")
         .blocklist_type("rhash_lock_head")
         .blocklist_type("srcu_struct")
-        .blocklist_type("bch_ioctl_data.*")
         .allowlist_var("BCH_.*")
         .allowlist_var("KEY_SPEC_.*")
         .allowlist_var("Fix753_.*")
diff --git a/libbcachefs/backpointers.c b/libbcachefs/backpointers.c
index ebeb6a5f..655be233 100644
--- a/libbcachefs/backpointers.c
+++ b/libbcachefs/backpointers.c
@@ -244,27 +244,31 @@ struct bkey_s_c bch2_backpointer_get_key(struct btree_trans *trans,
 	if (unlikely(bp.v->btree_id >= btree_id_nr_alive(c)))
 		return bkey_s_c_null;
 
-	if (likely(!bp.v->level)) {
-		bch2_trans_node_iter_init(trans, iter,
-					  bp.v->btree_id,
-					  bp.v->pos,
-					  0, 0,
-					  iter_flags);
-		struct bkey_s_c k = bch2_btree_iter_peek_slot(iter);
-		if (bkey_err(k)) {
-			bch2_trans_iter_exit(trans, iter);
-			return k;
-		}
-
-		if (k.k &&
-		    extent_matches_bp(c, bp.v->btree_id, bp.v->level, k, bp))
-			return k;
-
+	bch2_trans_node_iter_init(trans, iter,
+				  bp.v->btree_id,
+				  bp.v->pos,
+				  0,
+				  bp.v->level,
+				  iter_flags);
+	struct bkey_s_c k = bch2_btree_iter_peek_slot(iter);
+	if (bkey_err(k)) {
 		bch2_trans_iter_exit(trans, iter);
+		return k;
+	}
+
+	if (k.k &&
+	    extent_matches_bp(c, bp.v->btree_id, bp.v->level, k, bp))
+		return k;
+
+	bch2_trans_iter_exit(trans, iter);
+
+	if (!bp.v->level) {
 		int ret = backpointer_target_not_found(trans, bp, k, last_flushed);
 		return ret ? bkey_s_c_err(ret) : bkey_s_c_null;
 	} else {
 		struct btree *b = bch2_backpointer_get_node(trans, bp, iter, last_flushed);
+		if (b == ERR_PTR(-BCH_ERR_backpointer_to_overwritten_btree_node))
+			return bkey_s_c_null;
 		if (IS_ERR_OR_NULL(b))
 			return ((struct bkey_s_c) { .k = ERR_CAST(b) });
 
diff --git a/libbcachefs/bcachefs.h b/libbcachefs/bcachefs.h
index 161cf2f0..13acfbf3 100644
--- a/libbcachefs/bcachefs.h
+++ b/libbcachefs/bcachefs.h
@@ -687,7 +687,8 @@ struct btree_trans_buf {
 	x(gc_gens)							\
 	x(snapshot_delete_pagecache)					\
 	x(sysfs)							\
-	x(btree_write_buffer)
+	x(btree_write_buffer)						\
+	x(btree_node_scrub)
 
 enum bch_write_ref {
 #define x(n) BCH_WRITE_REF_##n,
diff --git a/libbcachefs/bcachefs_ioctl.h b/libbcachefs/bcachefs_ioctl.h
index 3c23bdf7..f176f192 100644
--- a/libbcachefs/bcachefs_ioctl.h
+++ b/libbcachefs/bcachefs_ioctl.h
@@ -213,6 +213,10 @@ struct bch_ioctl_data {
 	struct bpos		end_pos;
 
 	union {
+	struct {
+		__u32		dev;
+		__u32		data_types;
+	}			scrub;
 	struct {
 		__u32		dev;
 		__u32		pad;
@@ -237,11 +241,19 @@ struct bch_ioctl_data_progress {
 
 	__u64			sectors_done;
 	__u64			sectors_total;
+	__u64			sectors_error_corrected;
+	__u64			sectors_error_uncorrected;
 } __packed __aligned(8);
 
+enum bch_ioctl_data_event_ret {
+	BCH_IOCTL_DATA_EVENT_RET_done		= 1,
+	BCH_IOCTL_DATA_EVENT_RET_device_offline	= 2,
+};
+
 struct bch_ioctl_data_event {
 	__u8			type;
-	__u8			pad[7];
+	__u8			ret;
+	__u8			pad[6];
 	union {
 	struct bch_ioctl_data_progress p;
 	__u64			pad2[15];
diff --git a/libbcachefs/btree_cache.c b/libbcachefs/btree_cache.c
index b00c6a20..672ca2c1 100644
--- a/libbcachefs/btree_cache.c
+++ b/libbcachefs/btree_cache.c
@@ -1402,18 +1402,24 @@ void bch2_btree_id_level_to_text(struct printbuf *out, enum btree_id btree, unsi
 	prt_printf(out, " level=%u", level);
 }
 
-void bch2_btree_pos_to_text(struct printbuf *out, struct bch_fs *c, const struct btree *b)
+void __bch2_btree_pos_to_text(struct printbuf *out, struct bch_fs *c,
+			      enum btree_id btree, unsigned level, struct bkey_s_c k)
 {
-	bch2_btree_id_to_text(out, b->c.btree_id);
-	prt_printf(out, " level %u/", b->c.level);
-	struct btree_root *r = bch2_btree_id_root(c, b->c.btree_id);
+	bch2_btree_id_to_text(out, btree);
+	prt_printf(out, " level %u/", level);
+	struct btree_root *r = bch2_btree_id_root(c, btree);
 	if (r)
 		prt_printf(out, "%u", r->level);
 	else
 		prt_printf(out, "(unknown)");
 	prt_printf(out, "\n  ");
 
-	bch2_bkey_val_to_text(out, c, bkey_i_to_s_c(&b->key));
+	bch2_bkey_val_to_text(out, c, k);
+}
+
+void bch2_btree_pos_to_text(struct printbuf *out, struct bch_fs *c, const struct btree *b)
+{
+	__bch2_btree_pos_to_text(out, c, b->c.btree_id, b->c.level, bkey_i_to_s_c(&b->key));
 }
 
 void bch2_btree_node_to_text(struct printbuf *out, struct bch_fs *c, const struct btree *b)
diff --git a/libbcachefs/btree_cache.h b/libbcachefs/btree_cache.h
index dcc34fe4..ca3c1b14 100644
--- a/libbcachefs/btree_cache.h
+++ b/libbcachefs/btree_cache.h
@@ -147,6 +147,8 @@ const char *bch2_btree_id_str(enum btree_id);	/* avoid */
 void bch2_btree_id_to_text(struct printbuf *, enum btree_id);
 void bch2_btree_id_level_to_text(struct printbuf *, enum btree_id, unsigned);
 
+void __bch2_btree_pos_to_text(struct printbuf *, struct bch_fs *,
+			      enum btree_id, unsigned, struct bkey_s_c);
 void bch2_btree_pos_to_text(struct printbuf *, struct bch_fs *, const struct btree *);
 void bch2_btree_node_to_text(struct printbuf *, struct bch_fs *, const struct btree *);
 void bch2_btree_cache_to_text(struct printbuf *, const struct btree_cache *);
diff --git a/libbcachefs/btree_io.c b/libbcachefs/btree_io.c
index e371e60e..13ab827d 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 "bkey_buf.h"
 #include "bkey_methods.h"
 #include "bkey_sort.h"
 #include "btree_cache.h"
@@ -1352,7 +1353,7 @@ start:
 
 		can_retry = bch2_bkey_pick_read_device(c,
 				bkey_i_to_s_c(&b->key),
-				&failed, &rb->pick) > 0;
+				&failed, &rb->pick, -1) > 0;
 
 		if (!bio->bi_status &&
 		    !bch2_btree_node_read_done(c, ca, b, can_retry, &saw_error)) {
@@ -1697,7 +1698,7 @@ void bch2_btree_node_read(struct btree_trans *trans, struct btree *b,
 		return;
 
 	ret = bch2_bkey_pick_read_device(c, bkey_i_to_s_c(&b->key),
-					 NULL, &pick);
+					 NULL, &pick, -1);
 
 	if (ret <= 0) {
 		struct printbuf buf = PRINTBUF;
@@ -1811,6 +1812,190 @@ int bch2_btree_root_read(struct bch_fs *c, enum btree_id id,
 	return bch2_trans_run(c, __bch2_btree_root_read(trans, id, k, level));
 }
 
+struct btree_node_scrub {
+	struct bch_fs		*c;
+	struct bch_dev		*ca;
+	void			*buf;
+	bool			used_mempool;
+	unsigned		written;
+
+	enum btree_id		btree;
+	unsigned		level;
+	struct bkey_buf		key;
+	__le64			seq;
+
+	struct work_struct	work;
+	struct bio		bio;
+};
+
+static bool btree_node_scrub_check(struct bch_fs *c, struct btree_node *data, unsigned ptr_written,
+				   struct printbuf *err)
+{
+	unsigned written = 0;
+
+	if (le64_to_cpu(data->magic) != bset_magic(c)) {
+		prt_printf(err, "bad magic: want %llx, got %llx",
+			   bset_magic(c), le64_to_cpu(data->magic));
+		return false;
+	}
+
+	while (written < (ptr_written ?: btree_sectors(c))) {
+		struct btree_node_entry *bne;
+		struct bset *i;
+		bool first = !written;
+
+		if (first) {
+			bne = NULL;
+			i = &data->keys;
+		} else {
+			bne = (void *) data + (written << 9);
+			i = &bne->keys;
+
+			if (!ptr_written && i->seq != data->keys.seq)
+				break;
+		}
+
+		struct nonce nonce = btree_nonce(i, written << 9);
+		bool good_csum_type = bch2_checksum_type_valid(c, BSET_CSUM_TYPE(i));
+
+		if (first) {
+			if (good_csum_type) {
+				struct bch_csum csum = csum_vstruct(c, BSET_CSUM_TYPE(i), nonce, data);
+				if (bch2_crc_cmp(data->csum, csum)) {
+					bch2_csum_err_msg(err, BSET_CSUM_TYPE(i), data->csum, csum);
+					return false;
+				}
+			}
+
+			written += vstruct_sectors(data, c->block_bits);
+		} else {
+			if (good_csum_type) {
+				struct bch_csum csum = csum_vstruct(c, BSET_CSUM_TYPE(i), nonce, bne);
+				if (bch2_crc_cmp(bne->csum, csum)) {
+					bch2_csum_err_msg(err, BSET_CSUM_TYPE(i), bne->csum, csum);
+					return false;
+				}
+			}
+
+			written += vstruct_sectors(bne, c->block_bits);
+		}
+	}
+
+	return true;
+}
+
+static void btree_node_scrub_work(struct work_struct *work)
+{
+	struct btree_node_scrub *scrub = container_of(work, struct btree_node_scrub, work);
+	struct bch_fs *c = scrub->c;
+	struct printbuf err = PRINTBUF;
+
+	__bch2_btree_pos_to_text(&err, c, scrub->btree, scrub->level,
+				 bkey_i_to_s_c(scrub->key.k));
+	prt_newline(&err);
+
+	if (!btree_node_scrub_check(c, scrub->buf, scrub->written, &err)) {
+		struct btree_trans *trans = bch2_trans_get(c);
+
+		struct btree_iter iter;
+		bch2_trans_node_iter_init(trans, &iter, scrub->btree,
+					  scrub->key.k->k.p, 0, scrub->level - 1, 0);
+
+		struct btree *b;
+		int ret = lockrestart_do(trans, PTR_ERR_OR_ZERO(b = bch2_btree_iter_peek_node(&iter)));
+		if (ret)
+			goto err;
+
+		if (bkey_i_to_btree_ptr_v2(&b->key)->v.seq == scrub->seq) {
+			bch_err(c, "error validating btree node during scrub on %s at btree %s",
+				scrub->ca->name, err.buf);
+
+			ret = bch2_btree_node_rewrite(trans, &iter, b, 0);
+		}
+err:
+		bch2_trans_iter_exit(trans, &iter);
+		bch2_trans_begin(trans);
+		bch2_trans_put(trans);
+	}
+
+	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);
+	kfree(scrub);
+	bch2_write_ref_put(c, BCH_WRITE_REF_btree_node_scrub);
+}
+
+static void btree_node_scrub_endio(struct bio *bio)
+{
+	struct btree_node_scrub *scrub = container_of(bio, struct btree_node_scrub, bio);
+
+	queue_work(scrub->c->btree_read_complete_wq, &scrub->work);
+}
+
+int bch2_btree_node_scrub(struct btree_trans *trans,
+			  enum btree_id btree, unsigned level,
+			  struct bkey_s_c k, unsigned dev)
+{
+	if (k.k->type != KEY_TYPE_btree_ptr_v2)
+		return 0;
+
+	struct bch_fs *c = trans->c;
+
+	if (!bch2_write_ref_tryget(c, BCH_WRITE_REF_btree_node_scrub))
+		return -BCH_ERR_erofs_no_writes;
+
+	struct extent_ptr_decoded pick;
+	int ret = bch2_bkey_pick_read_device(c, k, NULL, &pick, dev);
+	if (ret <= 0)
+		goto err;
+
+	struct bch_dev *ca = bch2_dev_get_ioref(c, pick.ptr.dev, READ);
+	if (!ca) {
+		ret = -BCH_ERR_device_offline;
+		goto err;
+	}
+
+	bool used_mempool = false;
+	void *buf = btree_bounce_alloc(c, c->opts.btree_node_size, &used_mempool);
+
+	unsigned vecs = buf_pages(buf, c->opts.btree_node_size);
+
+	struct btree_node_scrub *scrub =
+		kzalloc(sizeof(*scrub) + sizeof(struct bio_vec) * vecs, GFP_KERNEL);
+	if (!scrub) {
+		ret = -ENOMEM;
+		goto err_free;
+	}
+
+	scrub->c		= c;
+	scrub->ca		= ca;
+	scrub->buf		= buf;
+	scrub->used_mempool	= used_mempool;
+	scrub->written		= btree_ptr_sectors_written(k);
+
+	scrub->btree		= btree;
+	scrub->level		= level;
+	bch2_bkey_buf_init(&scrub->key);
+	bch2_bkey_buf_reassemble(&scrub->key, c, k);
+	scrub->seq		= bkey_s_c_to_btree_ptr_v2(k).v->seq;
+
+	INIT_WORK(&scrub->work, btree_node_scrub_work);
+
+	bio_init(&scrub->bio, ca->disk_sb.bdev, scrub->bio.bi_inline_vecs, vecs, REQ_OP_READ);
+	bch2_bio_map(&scrub->bio, scrub->buf, c->opts.btree_node_size);
+	scrub->bio.bi_iter.bi_sector	= pick.ptr.offset;
+	scrub->bio.bi_end_io		= btree_node_scrub_endio;
+	submit_bio(&scrub->bio);
+	return 0;
+err_free:
+	btree_bounce_free(c, c->opts.btree_node_size, used_mempool, buf);
+	percpu_ref_put(&ca->io_ref);
+err:
+	bch2_write_ref_put(c, BCH_WRITE_REF_btree_node_scrub);
+	return ret;
+}
+
 static void bch2_btree_complete_write(struct bch_fs *c, struct btree *b,
 				      struct btree_write *w)
 {
diff --git a/libbcachefs/btree_io.h b/libbcachefs/btree_io.h
index 6f9e4a6d..75ead381 100644
--- a/libbcachefs/btree_io.h
+++ b/libbcachefs/btree_io.h
@@ -132,6 +132,9 @@ 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);
 
+int bch2_btree_node_scrub(struct btree_trans *, enum btree_id, unsigned,
+			  struct bkey_s_c, unsigned);
+
 bool bch2_btree_post_write_cleanup(struct bch_fs *, struct btree *);
 
 enum btree_write_flags {
diff --git a/libbcachefs/btree_iter.c b/libbcachefs/btree_iter.c
index c291d495..367231ab 100644
--- a/libbcachefs/btree_iter.c
+++ b/libbcachefs/btree_iter.c
@@ -2770,6 +2770,10 @@ struct bkey_s_c bch2_btree_iter_peek_slot(struct btree_iter *iter)
 		goto out_no_locked;
 	}
 
+	struct btree_path *path = btree_iter_path(trans, iter);
+	if (unlikely(!btree_path_node(path, path->level)))
+		return bkey_s_c_null;
+
 	if ((iter->flags & BTREE_ITER_cached) ||
 	    !(iter->flags & (BTREE_ITER_is_extents|BTREE_ITER_filter_snapshots))) {
 		k = bkey_s_c_null;
diff --git a/libbcachefs/btree_update_interior.c b/libbcachefs/btree_update_interior.c
index f4aeadbe..ab111fec 100644
--- a/libbcachefs/btree_update_interior.c
+++ b/libbcachefs/btree_update_interior.c
@@ -2189,6 +2189,26 @@ err:
 	goto out;
 }
 
+int bch2_btree_node_rewrite_key(struct btree_trans *trans,
+				enum btree_id btree, unsigned level,
+				struct bpos pos, unsigned flags)
+{
+	BUG_ON(!level);
+
+	/* Traverse one depth lower to get a pointer to the node itself: */
+	struct btree_iter iter;
+	bch2_trans_node_iter_init(trans, &iter, btree, pos, 0, level - 1, 0);
+	struct btree *b = bch2_btree_iter_peek_node(&iter);
+	int ret = PTR_ERR_OR_ZERO(b);
+	if (ret)
+		goto err;
+
+	ret = bch2_btree_node_rewrite(trans, &iter, b, flags);
+err:
+	bch2_trans_iter_exit(trans, &iter);
+	return ret;
+}
+
 struct async_btree_rewrite {
 	struct bch_fs		*c;
 	struct work_struct	work;
diff --git a/libbcachefs/btree_update_interior.h b/libbcachefs/btree_update_interior.h
index 7930ffea..fa5a88f9 100644
--- a/libbcachefs/btree_update_interior.h
+++ b/libbcachefs/btree_update_interior.h
@@ -169,7 +169,11 @@ static inline int bch2_foreground_maybe_merge(struct btree_trans *trans,
 
 int bch2_btree_node_rewrite(struct btree_trans *, struct btree_iter *,
 			    struct btree *, unsigned);
+int bch2_btree_node_rewrite_key(struct btree_trans *,
+				enum btree_id, unsigned,
+				struct bpos, unsigned);
 void bch2_btree_node_rewrite_async(struct bch_fs *, struct btree *);
+
 int bch2_btree_node_update_key(struct btree_trans *, struct btree_iter *,
 			       struct btree *, struct bkey_i *,
 			       unsigned, bool);
diff --git a/libbcachefs/chardev.c b/libbcachefs/chardev.c
index 46e9e321..0eb32074 100644
--- a/libbcachefs/chardev.c
+++ b/libbcachefs/chardev.c
@@ -312,7 +312,10 @@ static int bch2_data_thread(void *arg)
 	struct bch_data_ctx *ctx = container_of(arg, struct bch_data_ctx, thr);
 
 	ctx->thr.ret = bch2_data_job(ctx->c, &ctx->stats, ctx->arg);
-	ctx->stats.data_type = U8_MAX;
+	if (ctx->thr.ret == -BCH_ERR_device_offline)
+		ctx->stats.ret = BCH_IOCTL_DATA_EVENT_RET_device_offline;
+	else
+		ctx->stats.ret = BCH_IOCTL_DATA_EVENT_RET_done;
 	return 0;
 }
 
@@ -331,14 +334,30 @@ static ssize_t bch2_data_job_read(struct file *file, char __user *buf,
 	struct bch_data_ctx *ctx = container_of(file->private_data, struct bch_data_ctx, thr);
 	struct bch_fs *c = ctx->c;
 	struct bch_ioctl_data_event e = {
-		.type			= BCH_DATA_EVENT_PROGRESS,
-		.p.data_type		= ctx->stats.data_type,
-		.p.btree_id		= ctx->stats.pos.btree,
-		.p.pos			= ctx->stats.pos.pos,
-		.p.sectors_done		= atomic64_read(&ctx->stats.sectors_seen),
-		.p.sectors_total	= bch2_fs_usage_read_short(c).used,
+		.type				= BCH_DATA_EVENT_PROGRESS,
+		.ret				= ctx->stats.ret,
+		.p.data_type			= ctx->stats.data_type,
+		.p.btree_id			= ctx->stats.pos.btree,
+		.p.pos				= ctx->stats.pos.pos,
+		.p.sectors_done			= atomic64_read(&ctx->stats.sectors_seen),
+		.p.sectors_error_corrected	= atomic64_read(&ctx->stats.sectors_error_corrected),
+		.p.sectors_error_uncorrected	= atomic64_read(&ctx->stats.sectors_error_uncorrected),
 	};
 
+	if (ctx->arg.op == BCH_DATA_OP_scrub) {
+		struct bch_dev *ca = bch2_dev_tryget(c, ctx->arg.scrub.dev);
+		if (ca) {
+			struct bch_dev_usage u;
+			bch2_dev_usage_read_fast(ca, &u);
+			for (unsigned i = BCH_DATA_btree; i < ARRAY_SIZE(u.d); i++)
+				if (ctx->arg.scrub.data_types & BIT(i))
+					e.p.sectors_total += u.d[i].sectors;
+			bch2_dev_put(ca);
+		}
+	} else {
+		e.p.sectors_total	= bch2_fs_usage_read_short(c).used;
+	}
+
 	if (len < sizeof(e))
 		return -EINVAL;
 
diff --git a/libbcachefs/data_update.h b/libbcachefs/data_update.h
index e4b50723..144b935c 100644
--- a/libbcachefs/data_update.h
+++ b/libbcachefs/data_update.h
@@ -15,6 +15,9 @@ struct data_update_opts {
 	u8		extra_replicas;
 	unsigned	btree_insert_flags;
 	unsigned	write_flags;
+
+	int		read_dev;
+	bool		scrub;
 };
 
 void bch2_data_update_opts_to_text(struct printbuf *, struct bch_fs *,
diff --git a/libbcachefs/debug.c b/libbcachefs/debug.c
index b5de52a5..3722c2ac 100644
--- a/libbcachefs/debug.c
+++ b/libbcachefs/debug.c
@@ -189,7 +189,7 @@ void bch2_btree_node_ondisk_to_text(struct printbuf *out, struct bch_fs *c,
 	unsigned offset = 0;
 	int ret;
 
-	if (bch2_bkey_pick_read_device(c, bkey_i_to_s_c(&b->key), NULL, &pick) <= 0) {
+	if (bch2_bkey_pick_read_device(c, bkey_i_to_s_c(&b->key), NULL, &pick, -1) <= 0) {
 		prt_printf(out, "error getting device to read from: invalid device\n");
 		return;
 	}
diff --git a/libbcachefs/errcode.h b/libbcachefs/errcode.h
index 4590cd0c..cae4fc3e 100644
--- a/libbcachefs/errcode.h
+++ b/libbcachefs/errcode.h
@@ -269,6 +269,7 @@
 	x(EIO,				invalidate_stripe_to_dev)		\
 	x(EIO,				no_encryption_key)			\
 	x(EIO,				insufficient_journal_devices)		\
+	x(EIO,				device_offline)				\
 	x(BCH_ERR_btree_node_read_err,	btree_node_read_err_fixable)		\
 	x(BCH_ERR_btree_node_read_err,	btree_node_read_err_want_retry)		\
 	x(BCH_ERR_btree_node_read_err,	btree_node_read_err_must_retry)		\
diff --git a/libbcachefs/extents.c b/libbcachefs/extents.c
index 05d5f71a..78a51d96 100644
--- a/libbcachefs/extents.c
+++ b/libbcachefs/extents.c
@@ -114,8 +114,9 @@ static inline bool ptr_better(struct bch_fs *c,
  * other devices, it will still pick a pointer from avoid.
  */
 int bch2_bkey_pick_read_device(struct bch_fs *c, struct bkey_s_c k,
-			       struct bch_io_failures *failed,
-			       struct extent_ptr_decoded *pick)
+			      struct bch_io_failures *failed,
+			      struct extent_ptr_decoded *pick,
+			      int dev)
 {
 	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
 	const union bch_extent_entry *entry;
@@ -137,6 +138,10 @@ int bch2_bkey_pick_read_device(struct bch_fs *c, struct bkey_s_c k,
 			break;
 		}
 
+		/* Are we being asked to read from a specific device? */
+		if (dev >= 0 && p.ptr.dev != dev)
+			continue;
+
 		/*
 		 * If there are any dirty pointers it's an error if we can't
 		 * read:
diff --git a/libbcachefs/extents.h b/libbcachefs/extents.h
index 620b284a..8fae6b23 100644
--- a/libbcachefs/extents.h
+++ b/libbcachefs/extents.h
@@ -404,7 +404,7 @@ void bch2_mark_io_failure(struct bch_io_failures *,
 			  struct extent_ptr_decoded *);
 int bch2_bkey_pick_read_device(struct bch_fs *, struct bkey_s_c,
 			       struct bch_io_failures *,
-			       struct extent_ptr_decoded *);
+			       struct extent_ptr_decoded *, int);
 
 /* KEY_TYPE_btree_ptr: */
 
diff --git a/libbcachefs/io_read.c b/libbcachefs/io_read.c
index 34a3569d..87fe5997 100644
--- a/libbcachefs/io_read.c
+++ b/libbcachefs/io_read.c
@@ -444,7 +444,7 @@ retry:
 	ret = __bch2_read_extent(trans, rbio, bvec_iter,
 				 rbio->read_pos,
 				 rbio->data_btree,
-				 k, 0, failed, flags);
+				 k, 0, failed, flags, -1);
 	if (ret == READ_RETRY)
 		goto retry;
 	if (ret)
@@ -499,6 +499,7 @@ static void bch2_rbio_error(struct bch_read_bio *rbio, int retry,
 			    blk_status_t error)
 {
 	rbio->retry = retry;
+	rbio->saw_error = true;
 
 	if (rbio->flags & BCH_READ_IN_RETRY)
 		return;
@@ -740,7 +741,7 @@ static void __bch2_read_endio(struct work_struct *work)
 			bio_copy_data_iter(dst, &dst_iter, src, &src_iter);
 		}
 	}
-
+nodecode:
 	if (rbio->promote) {
 		/*
 		 * Re encrypt data we decrypted, so it's consistent with
@@ -753,7 +754,7 @@ static void __bch2_read_endio(struct work_struct *work)
 		promote_start(rbio->promote, rbio);
 		rbio->promote = NULL;
 	}
-nodecode:
+
 	if (likely(!(rbio->flags & BCH_READ_IN_RETRY))) {
 		rbio = bch2_rbio_free(rbio);
 		bch2_rbio_done(rbio);
@@ -878,7 +879,7 @@ int __bch2_read_extent(struct btree_trans *trans, struct bch_read_bio *orig,
 		       struct bvec_iter iter, struct bpos read_pos,
 		       enum btree_id data_btree, struct bkey_s_c k,
 		       unsigned offset_into_extent,
-		       struct bch_io_failures *failed, unsigned flags)
+		       struct bch_io_failures *failed, unsigned flags, int dev)
 {
 	struct bch_fs *c = trans->c;
 	struct extent_ptr_decoded pick;
@@ -888,6 +889,8 @@ int __bch2_read_extent(struct btree_trans *trans, struct bch_read_bio *orig,
 	struct bpos data_pos = bkey_start_pos(k.k);
 	int pick_ret;
 
+	//BUG_ON(failed && failed->nr);
+
 	if (bkey_extent_is_inline_data(k.k)) {
 		unsigned bytes = min_t(unsigned, iter.bi_size,
 				       bkey_inline_data_bytes(k.k));
@@ -900,7 +903,7 @@ int __bch2_read_extent(struct btree_trans *trans, struct bch_read_bio *orig,
 		goto out_read_done;
 	}
 retry_pick:
-	pick_ret = bch2_bkey_pick_read_device(c, k, failed, &pick);
+	pick_ret = bch2_bkey_pick_read_device(c, k, failed, &pick, dev);
 
 	/* hole or reservation - just zero fill: */
 	if (!pick_ret)
@@ -952,7 +955,30 @@ retry_pick:
 	 */
 	bch2_trans_unlock(trans);
 
-	if (flags & BCH_READ_NODECODE) {
+	if (!(flags & BCH_READ_NODECODE)) {
+		if (!(flags & BCH_READ_LAST_FRAGMENT) ||
+		    bio_flagged(&orig->bio, BIO_CHAIN))
+			flags |= BCH_READ_MUST_CLONE;
+
+		narrow_crcs = !(flags & BCH_READ_IN_RETRY) &&
+			bch2_can_narrow_extent_crcs(k, pick.crc);
+
+		if (narrow_crcs && (flags & BCH_READ_USER_MAPPED))
+			flags |= BCH_READ_MUST_BOUNCE;
+
+		EBUG_ON(offset_into_extent + bvec_iter_sectors(iter) > k.k->size);
+
+		if (crc_is_compressed(pick.crc) ||
+		    (pick.crc.csum_type != BCH_CSUM_none &&
+		     (bvec_iter_sectors(iter) != pick.crc.uncompressed_size ||
+		      (bch2_csum_type_is_encryption(pick.crc.csum_type) &&
+		       (flags & BCH_READ_USER_MAPPED)) ||
+		      (flags & BCH_READ_MUST_BOUNCE)))) {
+			read_full = true;
+			bounce = true;
+		}
+	} else {
+		read_full = true;
 		/*
 		 * can happen if we retry, and the extent we were going to read
 		 * has been merged in the meantime:
@@ -964,32 +990,10 @@ retry_pick:
 		}
 
 		iter.bi_size	= pick.crc.compressed_size << 9;
-		goto get_bio;
 	}
 
-	if (!(flags & BCH_READ_LAST_FRAGMENT) ||
-	    bio_flagged(&orig->bio, BIO_CHAIN))
-		flags |= BCH_READ_MUST_CLONE;
-
-	narrow_crcs = !(flags & BCH_READ_IN_RETRY) &&
-		bch2_can_narrow_extent_crcs(k, pick.crc);
-
-	if (narrow_crcs && (flags & BCH_READ_USER_MAPPED))
-		flags |= BCH_READ_MUST_BOUNCE;
-
-	EBUG_ON(offset_into_extent + bvec_iter_sectors(iter) > k.k->size);
-
-	if (crc_is_compressed(pick.crc) ||
-	    (pick.crc.csum_type != BCH_CSUM_none &&
-	     (bvec_iter_sectors(iter) != pick.crc.uncompressed_size ||
-	      (bch2_csum_type_is_encryption(pick.crc.csum_type) &&
-	       (flags & BCH_READ_USER_MAPPED)) ||
-	      (flags & BCH_READ_MUST_BOUNCE)))) {
-		read_full = true;
-		bounce = true;
-	}
-
-	if (orig->opts.promote_target)// || failed)
+	if ((orig->opts.promote_target && !(flags & BCH_READ_NODECODE)) ||
+	    (failed && failed->nr))
 		promote = promote_alloc(trans, iter, k, &pick, orig->opts, flags,
 					&rbio, &bounce, &read_full, failed);
 
@@ -1010,7 +1014,7 @@ retry_pick:
 		pick.crc.offset			= 0;
 		pick.crc.live_size		= bvec_iter_sectors(iter);
 	}
-get_bio:
+
 	if (rbio) {
 		/*
 		 * promote already allocated bounce rbio:
@@ -1261,7 +1265,7 @@ void __bch2_read(struct bch_fs *c, struct bch_read_bio *rbio,
 
 		ret = __bch2_read_extent(trans, rbio, bvec_iter, iter.pos,
 					 data_btree, k,
-					 offset_into_extent, failed, flags);
+					 offset_into_extent, failed, flags, -1);
 		if (ret)
 			goto err;
 
diff --git a/libbcachefs/io_read.h b/libbcachefs/io_read.h
index a82e8a94..b62fcee7 100644
--- a/libbcachefs/io_read.h
+++ b/libbcachefs/io_read.h
@@ -41,6 +41,7 @@ struct bch_read_bio {
 				have_ioref:1,
 				narrow_crcs:1,
 				hole:1,
+				saw_error:1,
 				retry:2,
 				context:2;
 	};
@@ -124,7 +125,7 @@ enum bch_read_flags {
 int __bch2_read_extent(struct btree_trans *, struct bch_read_bio *,
 		       struct bvec_iter, struct bpos, enum btree_id,
 		       struct bkey_s_c, unsigned,
-		       struct bch_io_failures *, unsigned);
+		       struct bch_io_failures *, unsigned, int);
 
 static inline void bch2_read_extent(struct btree_trans *trans,
 			struct bch_read_bio *rbio, struct bpos read_pos,
@@ -132,7 +133,7 @@ static inline void bch2_read_extent(struct btree_trans *trans,
 			unsigned offset_into_extent, unsigned flags)
 {
 	__bch2_read_extent(trans, rbio, rbio->bio.bi_iter, read_pos,
-			   data_btree, k, offset_into_extent, NULL, flags);
+			   data_btree, k, offset_into_extent, NULL, flags, -1);
 }
 
 void __bch2_read(struct bch_fs *, struct bch_read_bio *, struct bvec_iter,
diff --git a/libbcachefs/move.c b/libbcachefs/move.c
index c493ea62..cc852492 100644
--- a/libbcachefs/move.c
+++ b/libbcachefs/move.c
@@ -114,7 +114,20 @@ static void move_write_done(struct bch_write_op *op)
 
 static void move_write(struct moving_io *io)
 {
-	if (unlikely(io->rbio.bio.bi_status || io->rbio.hole)) {
+	struct moving_context *ctxt = io->write.ctxt;
+
+	if (ctxt->stats) {
+		if (io->rbio.bio.bi_status)
+			atomic64_add(io->rbio.bvec_iter.bi_size >> 9,
+				     &ctxt->stats->sectors_error_uncorrected);
+		else if (io->rbio.saw_error)
+			atomic64_add(io->rbio.bvec_iter.bi_size >> 9,
+				     &ctxt->stats->sectors_error_corrected);
+	}
+
+	if (unlikely(io->rbio.bio.bi_status ||
+		     io->rbio.hole ||
+		     io->write.data_opts.scrub)) {
 		move_free(io);
 		return;
 	}
@@ -273,7 +286,8 @@ int bch2_move_extent(struct moving_context *ctxt,
 	bch2_data_update_opts_normalize(k, &data_opts);
 
 	if (!data_opts.rewrite_ptrs &&
-	    !data_opts.extra_replicas) {
+	    !data_opts.extra_replicas &&
+	    !data_opts.scrub) {
 		if (data_opts.kill_ptrs)
 			return bch2_extent_drop_ptrs(trans, iter, k, &io_opts, &data_opts);
 		return 0;
@@ -319,12 +333,18 @@ int bch2_move_extent(struct moving_context *ctxt,
 	io->rbio.bio.bi_iter.bi_sector	= bkey_start_offset(k.k);
 	io->rbio.bio.bi_end_io		= move_read_endio;
 
-	ret = bch2_data_update_init(trans, iter, ctxt, &io->write, ctxt->wp,
-				    io_opts, data_opts, iter->btree_id, k);
-	if (ret)
-		goto err_free_pages;
+	if (!data_opts.scrub) {
+		ret = bch2_data_update_init(trans, iter, ctxt, &io->write, ctxt->wp,
+					    io_opts, data_opts, iter->btree_id, k);
+		if (ret)
+			goto err_free_pages;
 
-	io->write.op.end_io = move_write_done;
+		io->write.op.end_io	= move_write_done;
+	} else {
+		bch2_bkey_buf_init(&io->write.k);
+		io->write.op.c		= c;
+		io->write.data_opts	= data_opts;
+	}
 
 	if (ctxt->rate)
 		bch2_ratelimit_increment(ctxt->rate, k.k->size);
@@ -356,11 +376,14 @@ int bch2_move_extent(struct moving_context *ctxt,
 	 * ctxt when doing wakeup
 	 */
 	closure_get(&ctxt->cl);
-	bch2_read_extent(trans, &io->rbio,
-			 bkey_start_pos(k.k),
-			 iter->btree_id, k, 0,
-			 BCH_READ_NODECODE|
-			 BCH_READ_LAST_FRAGMENT);
+	__bch2_read_extent(trans, &io->rbio,
+			   io->rbio.bio.bi_iter,
+			   bkey_start_pos(k.k),
+			   iter->btree_id, k, 0,
+			   NULL,
+			   BCH_READ_NODECODE|
+			   BCH_READ_LAST_FRAGMENT,
+			   data_opts.scrub ?  data_opts.read_dev : -1);
 	return 0;
 err_free_pages:
 	bio_free_pages(&io->write.op.wbio.bio);
@@ -689,21 +712,22 @@ int bch2_move_data(struct bch_fs *c,
 		   bool wait_on_copygc,
 		   move_pred_fn pred, void *arg)
 {
-
 	struct moving_context ctxt;
-	int ret;
 
 	bch2_moving_ctxt_init(&ctxt, c, rate, stats, wp, wait_on_copygc);
-	ret = __bch2_move_data(&ctxt, start, end, pred, arg);
+	int ret = __bch2_move_data(&ctxt, start, end, pred, arg);
 	bch2_moving_ctxt_exit(&ctxt);
 
 	return ret;
 }
 
-int bch2_evacuate_bucket(struct moving_context *ctxt,
-			   struct move_bucket_in_flight *bucket_in_flight,
-			   struct bpos bucket, int gen,
-			   struct data_update_opts _data_opts)
+static int __bch2_move_data_phys(struct moving_context *ctxt,
+			struct move_bucket_in_flight *bucket_in_flight,
+			unsigned dev,
+			u64 bucket_start,
+			u64 bucket_end,
+			unsigned data_types,
+			move_pred_fn pred, void *arg)
 {
 	struct btree_trans *trans = ctxt->trans;
 	struct bch_fs *c = trans->c;
@@ -712,16 +736,22 @@ int bch2_evacuate_bucket(struct moving_context *ctxt,
 	struct btree_iter iter = {}, bp_iter = {};
 	struct bkey_buf sk;
 	struct bkey_s_c k;
-	struct data_update_opts data_opts;
 	unsigned sectors_moved = 0;
 	struct bkey_buf last_flushed;
 	int ret = 0;
 
-	struct bch_dev *ca = bch2_dev_tryget(c, bucket.inode);
+	struct bch_dev *ca = bch2_dev_tryget(c, dev);
 	if (!ca)
 		return 0;
 
-	trace_bucket_evacuate(c, &bucket);
+	bucket_end = min(bucket_end, ca->mi.nbuckets);
+
+	struct bpos bp_start	= bucket_pos_to_bp_start(ca, POS(dev, bucket_start));
+	struct bpos bp_end	= bucket_pos_to_bp_end(ca, POS(dev, bucket_end));
+	bch2_dev_put(ca);
+	ca = NULL;
+
+	//trace_bucket_evacuate(c, &bucket);
 
 	bch2_bkey_buf_init(&last_flushed);
 	bkey_init(&last_flushed.k->k);
@@ -732,8 +762,7 @@ int bch2_evacuate_bucket(struct moving_context *ctxt,
 	 */
 	bch2_trans_begin(trans);
 
-	bch2_trans_iter_init(trans, &bp_iter, BTREE_ID_backpointers,
-			     bucket_pos_to_bp_start(ca, bucket), 0);
+	bch2_trans_iter_init(trans, &bp_iter, BTREE_ID_backpointers, bp_start, 0);
 
 	bch_err_msg(c, ret, "looking up alloc key");
 	if (ret)
@@ -757,7 +786,7 @@ int bch2_evacuate_bucket(struct moving_context *ctxt,
 		if (ret)
 			goto err;
 
-		if (!k.k || bkey_gt(k.k->p, bucket_pos_to_bp_end(ca, bucket)))
+		if (!k.k || bkey_gt(k.k->p, bp_end))
 			break;
 
 		if (k.k->type != KEY_TYPE_backpointer)
@@ -765,107 +794,145 @@ int bch2_evacuate_bucket(struct moving_context *ctxt,
 
 		struct bkey_s_c_backpointer bp = bkey_s_c_to_backpointer(k);
 
+		if (ctxt->stats)
+			ctxt->stats->offset = bp.k->p.offset >> MAX_EXTENT_COMPRESS_RATIO_SHIFT;
+
+		if (!(data_types & BIT(bp.v->data_type)))
+			goto next;
+
+		k = bch2_backpointer_get_key(trans, bp, &iter, 0, &last_flushed);
+		ret = bkey_err(k);
+		if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
+			continue;
+		if (ret)
+			goto err;
+		if (!k.k)
+			goto next;
+
 		if (!bp.v->level) {
-			k = bch2_backpointer_get_key(trans, bp, &iter, 0, &last_flushed);
-			ret = bkey_err(k);
-			if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
-				continue;
-			if (ret)
-				goto err;
-			if (!k.k)
-				goto next;
-
-			bch2_bkey_buf_reassemble(&sk, c, k);
-			k = bkey_i_to_s_c(sk.k);
-
 			ret = bch2_move_get_io_opts_one(trans, &io_opts, &iter, k);
 			if (ret) {
 				bch2_trans_iter_exit(trans, &iter);
 				continue;
 			}
-
-			data_opts = _data_opts;
-			data_opts.target	= io_opts.background_target;
-			data_opts.rewrite_ptrs = 0;
-
-			unsigned sectors = bp.v->bucket_len; /* move_extent will drop locks */
-			unsigned i = 0;
-			const union bch_extent_entry *entry;
-			struct extent_ptr_decoded p;
-			bkey_for_each_ptr_decode(k.k, bch2_bkey_ptrs_c(k), p, entry) {
-				if (p.ptr.dev == bucket.inode) {
-					if (p.ptr.cached) {
-						bch2_trans_iter_exit(trans, &iter);
-						goto next;
-					}
-					data_opts.rewrite_ptrs |= 1U << i;
-					break;
-				}
-				i++;
-			}
-
-			ret = bch2_move_extent(ctxt, bucket_in_flight,
-					       &iter, k, io_opts, data_opts);
-			bch2_trans_iter_exit(trans, &iter);
-
-			if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
-				continue;
-			if (ret == -ENOMEM) {
-				/* memory allocation failure, wait for some IO to finish */
-				bch2_move_ctxt_wait_for_io(ctxt);
-				continue;
-			}
-			if (ret)
-				goto err;
-
-			if (ctxt->stats)
-				atomic64_add(sectors, &ctxt->stats->sectors_seen);
-			sectors_moved += sectors;
-		} else {
-			struct btree *b;
-
-			b = bch2_backpointer_get_node(trans, bp, &iter, &last_flushed);
-			ret = PTR_ERR_OR_ZERO(b);
-			if (ret == -BCH_ERR_backpointer_to_overwritten_btree_node)
-				goto next;
-			if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
-				continue;
-			if (ret)
-				goto err;
-			if (!b)
-				goto next;
-
-			unsigned sectors = btree_ptr_sectors_written(bkey_i_to_s_c(&b->key));
-
-			ret = bch2_btree_node_rewrite(trans, &iter, b, 0);
-			bch2_trans_iter_exit(trans, &iter);
-
-			if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
-				continue;
-			if (ret)
-				goto err;
-
-			if (ctxt->rate)
-				bch2_ratelimit_increment(ctxt->rate, sectors);
-			if (ctxt->stats) {
-				atomic64_add(sectors, &ctxt->stats->sectors_seen);
-				atomic64_add(sectors, &ctxt->stats->sectors_moved);
-			}
-			sectors_moved += btree_sectors(c);
 		}
+
+		struct data_update_opts data_opts = {};
+		if (!pred(c, arg, k, &io_opts, &data_opts)) {
+			bch2_trans_iter_exit(trans, &iter);
+			goto next;
+		}
+
+		if (data_opts.scrub &&
+		    !bch2_dev_idx_is_online(c, data_opts.read_dev)) {
+			bch2_trans_iter_exit(trans, &iter);
+			ret = -BCH_ERR_device_offline;
+			break;
+		}
+
+		bch2_bkey_buf_reassemble(&sk, c, k);
+		k = bkey_i_to_s_c(sk.k);
+
+		/* move_extent will drop locks */
+		unsigned sectors = bp.v->bucket_len;
+
+		if (!bp.v->level)
+			ret = bch2_move_extent(ctxt, bucket_in_flight, &iter, k, io_opts, data_opts);
+		else if (!data_opts.scrub)
+			ret = bch2_btree_node_rewrite_key(trans, bp.v->btree_id, bp.v->level, k.k->p, 0);
+		else
+			ret = bch2_btree_node_scrub(trans, bp.v->btree_id, bp.v->level, k, data_opts.read_dev);
+
+		bch2_trans_iter_exit(trans, &iter);
+
+		if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
+			continue;
+		if (ret == -ENOMEM) {
+			/* memory allocation failure, wait for some IO to finish */
+			bch2_move_ctxt_wait_for_io(ctxt);
+			continue;
+		}
+		if (ret)
+			goto err;
+
+		if (ctxt->stats)
+			atomic64_add(sectors, &ctxt->stats->sectors_seen);
+		sectors_moved += sectors;
 next:
 		bch2_btree_iter_advance(&bp_iter);
 	}
 
-	trace_evacuate_bucket(c, &bucket, sectors_moved, ca->mi.bucket_size, ret);
+	//trace_evacuate_bucket(c, &bucket, sectors_moved, ca->mi.bucket_size, ret);
 err:
 	bch2_trans_iter_exit(trans, &bp_iter);
-	bch2_dev_put(ca);
 	bch2_bkey_buf_exit(&sk, c);
 	bch2_bkey_buf_exit(&last_flushed, c);
 	return ret;
 }
 
+static int bch2_move_data_phys(struct bch_fs *c,
+			       unsigned dev,
+			       u64 start,
+			       u64 end,
+			       unsigned data_types,
+			       struct bch_ratelimit *rate,
+			       struct bch_move_stats *stats,
+			       struct write_point_specifier wp,
+			       bool wait_on_copygc,
+			       move_pred_fn pred, void *arg)
+{
+	struct moving_context ctxt;
+
+	bch2_trans_run(c, bch2_btree_write_buffer_flush_sync(trans));
+
+	bch2_moving_ctxt_init(&ctxt, c, rate, stats, wp, wait_on_copygc);
+	ctxt.stats->phys = true;
+
+	int ret = __bch2_move_data_phys(&ctxt, NULL, dev, start, end, data_types, pred, arg);
+	bch2_moving_ctxt_exit(&ctxt);
+
+	return ret;
+}
+
+struct evacuate_bucket_arg {
+	struct bpos		bucket;
+	int			gen;
+	struct data_update_opts	data_opts;
+};
+
+static bool evacuate_bucket_pred(struct bch_fs *c, void *_arg, struct bkey_s_c k,
+				 struct bch_io_opts *io_opts,
+				 struct data_update_opts *data_opts)
+{
+	struct evacuate_bucket_arg *arg = _arg;
+
+	*data_opts = arg->data_opts;
+
+	unsigned i = 0;
+	bkey_for_each_ptr(bch2_bkey_ptrs_c(k), ptr) {
+		if (ptr->dev == arg->bucket.inode && !ptr->cached)
+			data_opts->rewrite_ptrs |= BIT(i);
+		i++;
+	}
+
+	return data_opts->rewrite_ptrs != 0;
+}
+
+int bch2_evacuate_bucket(struct moving_context *ctxt,
+			   struct move_bucket_in_flight *bucket_in_flight,
+			   struct bpos bucket, int gen,
+			   struct data_update_opts data_opts)
+{
+	struct evacuate_bucket_arg arg = { bucket, gen, data_opts, };
+
+	return __bch2_move_data_phys(ctxt, bucket_in_flight,
+				   bucket.inode,
+				   bucket.offset,
+				   bucket.offset + 1,
+				   ~0,
+				   evacuate_bucket_pred, &arg);
+}
+
 typedef bool (*move_btree_pred)(struct bch_fs *, void *,
 				struct btree *, struct bch_io_opts *,
 				struct data_update_opts *);
@@ -1104,6 +1171,30 @@ static bool drop_extra_replicas_btree_pred(struct bch_fs *c, void *arg,
 	return drop_extra_replicas_pred(c, arg, bkey_i_to_s_c(&b->key), io_opts, data_opts);
 }
 
+static bool scrub_pred(struct bch_fs *c, void *_arg,
+		       struct bkey_s_c k,
+		       struct bch_io_opts *io_opts,
+		       struct data_update_opts *data_opts)
+{
+	struct bch_ioctl_data *arg = _arg;
+
+	if (k.k->type != KEY_TYPE_btree_ptr_v2) {
+		struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
+		const union bch_extent_entry *entry;
+		struct extent_ptr_decoded p;
+		bkey_for_each_ptr_decode(k.k, ptrs, p, entry)
+			if (p.ptr.dev == arg->migrate.dev) {
+				if (!p.crc.csum_type)
+					return false;
+				break;
+			}
+	}
+
+	data_opts->scrub	= true;
+	data_opts->read_dev	= arg->migrate.dev;
+	return true;
+}
+
 int bch2_data_job(struct bch_fs *c,
 		  struct bch_move_stats *stats,
 		  struct bch_ioctl_data op)
@@ -1118,6 +1209,16 @@ int bch2_data_job(struct bch_fs *c,
 	bch2_move_stats_init(stats, bch2_data_ops_strs[op.op]);
 
 	switch (op.op) {
+	case BCH_DATA_OP_scrub:
+		ret = bch2_move_data_phys(c, op.scrub.dev, 0, U64_MAX,
+					  op.scrub.data_types,
+					  NULL,
+					  stats,
+					  writepoint_hashed((unsigned long) current),
+					  false,
+					  scrub_pred, &op) ?: ret;
+		break;
+
 	case BCH_DATA_OP_rereplicate:
 		stats->data_type = BCH_DATA_journal;
 		ret = bch2_journal_flush_device_pins(&c->journal, -1);
diff --git a/libbcachefs/move_types.h b/libbcachefs/move_types.h
index e22841ef..82e473ed 100644
--- a/libbcachefs/move_types.h
+++ b/libbcachefs/move_types.h
@@ -3,17 +3,31 @@
 #define _BCACHEFS_MOVE_TYPES_H
 
 #include "bbpos_types.h"
+#include "bcachefs_ioctl.h"
 
 struct bch_move_stats {
-	enum bch_data_type	data_type;
-	struct bbpos		pos;
 	char			name[32];
+	bool			phys;
+	enum bch_ioctl_data_event_ret	ret;
+
+	union {
+	struct {
+		enum bch_data_type	data_type;
+		struct bbpos		pos;
+	};
+	struct {
+		unsigned		dev;
+		u64			offset;
+	};
+	};
 
 	atomic64_t		keys_moved;
 	atomic64_t		keys_raced;
 	atomic64_t		sectors_seen;
 	atomic64_t		sectors_moved;
 	atomic64_t		sectors_raced;
+	atomic64_t		sectors_error_corrected;
+	atomic64_t		sectors_error_uncorrected;
 };
 
 struct move_bucket_key {
diff --git a/libbcachefs/printbuf.h b/libbcachefs/printbuf.h
index 1d570387..d0dd398b 100644
--- a/libbcachefs/printbuf.h
+++ b/libbcachefs/printbuf.h
@@ -251,16 +251,23 @@ static inline void prt_hex_byte_upper(struct printbuf *out, u8 byte)
 	printbuf_nul_terminate_reserved(out);
 }
 
+static inline void printbuf_reset_keep_tabstops(struct printbuf *buf)
+{
+	buf->pos		= 0;
+	buf->allocation_failure	= 0;
+	buf->last_newline	= 0;
+	buf->last_field		= 0;
+	buf->indent		= 0;
+	buf->cur_tabstop	= 0;
+}
+
 /**
  * printbuf_reset - re-use a printbuf without freeing and re-initializing it:
  */
 static inline void printbuf_reset(struct printbuf *buf)
 {
-	buf->pos		= 0;
-	buf->allocation_failure	= 0;
-	buf->indent		= 0;
+	printbuf_reset_keep_tabstops(buf);
 	buf->nr_tabstops	= 0;
-	buf->cur_tabstop	= 0;
 }
 
 /**
diff --git a/libbcachefs/sb-members.h b/libbcachefs/sb-members.h
index 762083b5..b29b6c6c 100644
--- a/libbcachefs/sb-members.h
+++ b/libbcachefs/sb-members.h
@@ -23,6 +23,18 @@ static inline bool bch2_dev_is_online(struct bch_dev *ca)
 	return !percpu_ref_is_zero(&ca->io_ref);
 }
 
+static inline struct bch_dev *bch2_dev_rcu(struct bch_fs *, unsigned);
+
+static inline bool bch2_dev_idx_is_online(struct bch_fs *c, unsigned dev)
+{
+	rcu_read_lock();
+	struct bch_dev *ca = bch2_dev_rcu(c, dev);
+	bool ret = ca && bch2_dev_is_online(ca);
+	rcu_read_unlock();
+
+	return ret;
+}
+
 static inline bool bch2_dev_is_readable(struct bch_dev *ca)
 {
 	return bch2_dev_is_online(ca) &&
diff --git a/libbcachefs/trace.h b/libbcachefs/trace.h
index 9d40b7d4..e4c7dc0e 100644
--- a/libbcachefs/trace.h
+++ b/libbcachefs/trace.h
@@ -785,27 +785,6 @@ TRACE_EVENT(bucket_invalidate,
 
 /* Moving IO */
 
-TRACE_EVENT(bucket_evacuate,
-	TP_PROTO(struct bch_fs *c, struct bpos *bucket),
-	TP_ARGS(c, bucket),
-
-	TP_STRUCT__entry(
-		__field(dev_t,		dev			)
-		__field(u32,		dev_idx			)
-		__field(u64,		bucket			)
-	),
-
-	TP_fast_assign(
-		__entry->dev		= c->dev;
-		__entry->dev_idx	= bucket->inode;
-		__entry->bucket		= bucket->offset;
-	),
-
-	TP_printk("%d:%d %u:%llu",
-		  MAJOR(__entry->dev), MINOR(__entry->dev),
-		  __entry->dev_idx, __entry->bucket)
-);
-
 DEFINE_EVENT(fs_str, move_extent,
 	TP_PROTO(struct bch_fs *c, const char *str),
 	TP_ARGS(c, str)
@@ -869,37 +848,6 @@ TRACE_EVENT(move_data,
 		  __entry->sectors_raced)
 );
 
-TRACE_EVENT(evacuate_bucket,
-	TP_PROTO(struct bch_fs *c, struct bpos *bucket,
-		 unsigned sectors, unsigned bucket_size,
-		 int ret),
-	TP_ARGS(c, bucket, sectors, bucket_size, ret),
-
-	TP_STRUCT__entry(
-		__field(dev_t,		dev		)
-		__field(u64,		member		)
-		__field(u64,		bucket		)
-		__field(u32,		sectors		)
-		__field(u32,		bucket_size	)
-		__field(int,		ret		)
-	),
-
-	TP_fast_assign(
-		__entry->dev			= c->dev;
-		__entry->member			= bucket->inode;
-		__entry->bucket			= bucket->offset;
-		__entry->sectors		= sectors;
-		__entry->bucket_size		= bucket_size;
-		__entry->ret			= ret;
-	),
-
-	TP_printk("%d,%d %llu:%llu sectors %u/%u ret %i",
-		  MAJOR(__entry->dev), MINOR(__entry->dev),
-		  __entry->member, __entry->bucket,
-		  __entry->sectors, __entry->bucket_size,
-		  __entry->ret)
-);
-
 TRACE_EVENT(copygc,
 	TP_PROTO(struct bch_fs *c,
 		 u64 sectors_moved, u64 sectors_not_moved,