1 files changed, 665 insertions, 0 deletions

diff --git a/c_src/libbcachefs/data_update.c b/c_src/libbcachefs/data_update.c
new file mode 100644
index 00000000..6f13477f
--- /dev/null
+++ b/c_src/libbcachefs/data_update.c
@@ -0,0 +1,665 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "bcachefs.h"
+#include "alloc_foreground.h"
+#include "bkey_buf.h"
+#include "btree_update.h"
+#include "buckets.h"
+#include "data_update.h"
+#include "ec.h"
+#include "error.h"
+#include "extents.h"
+#include "io_write.h"
+#include "keylist.h"
+#include "move.h"
+#include "nocow_locking.h"
+#include "rebalance.h"
+#include "subvolume.h"
+#include "trace.h"
+
+static void trace_move_extent_finish2(struct bch_fs *c, struct bkey_s_c k)
+{
+	if (trace_move_extent_finish_enabled()) {
+		struct printbuf buf = PRINTBUF;
+
+		bch2_bkey_val_to_text(&buf, c, k);
+		trace_move_extent_finish(c, buf.buf);
+		printbuf_exit(&buf);
+	}
+}
+
+static void trace_move_extent_fail2(struct data_update *m,
+			 struct bkey_s_c new,
+			 struct bkey_s_c wrote,
+			 struct bkey_i *insert,
+			 const char *msg)
+{
+	struct bch_fs *c = m->op.c;
+	struct bkey_s_c old = bkey_i_to_s_c(m->k.k);
+	const union bch_extent_entry *entry;
+	struct bch_extent_ptr *ptr;
+	struct extent_ptr_decoded p;
+	struct printbuf buf = PRINTBUF;
+	unsigned i, rewrites_found = 0;
+
+	if (!trace_move_extent_fail_enabled())
+		return;
+
+	prt_str(&buf, msg);
+
+	if (insert) {
+		i = 0;
+		bkey_for_each_ptr_decode(old.k, bch2_bkey_ptrs_c(old), p, entry) {
+			if (((1U << i) & m->data_opts.rewrite_ptrs) &&
+			    (ptr = bch2_extent_has_ptr(old, p, bkey_i_to_s(insert))) &&
+			    !ptr->cached)
+				rewrites_found |= 1U << i;
+			i++;
+		}
+	}
+
+	prt_printf(&buf, "\nrewrite ptrs:   %u%u%u%u",
+		   (m->data_opts.rewrite_ptrs & (1 << 0)) != 0,
+		   (m->data_opts.rewrite_ptrs & (1 << 1)) != 0,
+		   (m->data_opts.rewrite_ptrs & (1 << 2)) != 0,
+		   (m->data_opts.rewrite_ptrs & (1 << 3)) != 0);
+
+	prt_printf(&buf, "\nrewrites found: %u%u%u%u",
+		   (rewrites_found & (1 << 0)) != 0,
+		   (rewrites_found & (1 << 1)) != 0,
+		   (rewrites_found & (1 << 2)) != 0,
+		   (rewrites_found & (1 << 3)) != 0);
+
+	prt_str(&buf, "\nold:    ");
+	bch2_bkey_val_to_text(&buf, c, old);
+
+	prt_str(&buf, "\nnew:    ");
+	bch2_bkey_val_to_text(&buf, c, new);
+
+	prt_str(&buf, "\nwrote:  ");
+	bch2_bkey_val_to_text(&buf, c, wrote);
+
+	if (insert) {
+		prt_str(&buf, "\ninsert: ");
+		bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(insert));
+	}
+
+	trace_move_extent_fail(c, buf.buf);
+	printbuf_exit(&buf);
+}
+
+static int __bch2_data_update_index_update(struct btree_trans *trans,
+					   struct bch_write_op *op)
+{
+	struct bch_fs *c = op->c;
+	struct btree_iter iter;
+	struct data_update *m =
+		container_of(op, struct data_update, op);
+	struct keylist *keys = &op->insert_keys;
+	struct bkey_buf _new, _insert;
+	int ret = 0;
+
+	bch2_bkey_buf_init(&_new);
+	bch2_bkey_buf_init(&_insert);
+	bch2_bkey_buf_realloc(&_insert, c, U8_MAX);
+
+	bch2_trans_iter_init(trans, &iter, m->btree_id,
+			     bkey_start_pos(&bch2_keylist_front(keys)->k),
+			     BTREE_ITER_SLOTS|BTREE_ITER_INTENT);
+
+	while (1) {
+		struct bkey_s_c k;
+		struct bkey_s_c old = bkey_i_to_s_c(m->k.k);
+		struct bkey_i *insert = NULL;
+		struct bkey_i_extent *new;
+		const union bch_extent_entry *entry_c;
+		union bch_extent_entry *entry;
+		struct extent_ptr_decoded p;
+		struct bch_extent_ptr *ptr;
+		const struct bch_extent_ptr *ptr_c;
+		struct bpos next_pos;
+		bool should_check_enospc;
+		s64 i_sectors_delta = 0, disk_sectors_delta = 0;
+		unsigned rewrites_found = 0, durability, i;
+
+		bch2_trans_begin(trans);
+
+		k = bch2_btree_iter_peek_slot(&iter);
+		ret = bkey_err(k);
+		if (ret)
+			goto err;
+
+		new = bkey_i_to_extent(bch2_keylist_front(keys));
+
+		if (!bch2_extents_match(k, old)) {
+			trace_move_extent_fail2(m, k, bkey_i_to_s_c(&new->k_i),
+						NULL, "no match:");
+			goto nowork;
+		}
+
+		bkey_reassemble(_insert.k, k);
+		insert = _insert.k;
+
+		bch2_bkey_buf_copy(&_new, c, bch2_keylist_front(keys));
+		new = bkey_i_to_extent(_new.k);
+		bch2_cut_front(iter.pos, &new->k_i);
+
+		bch2_cut_front(iter.pos,	insert);
+		bch2_cut_back(new->k.p,		insert);
+		bch2_cut_back(insert->k.p,	&new->k_i);
+
+		/*
+		 * @old: extent that we read from
+		 * @insert: key that we're going to update, initialized from
+		 * extent currently in btree - same as @old unless we raced with
+		 * other updates
+		 * @new: extent with new pointers that we'll be adding to @insert
+		 *
+		 * Fist, drop rewrite_ptrs from @new:
+		 */
+		i = 0;
+		bkey_for_each_ptr_decode(old.k, bch2_bkey_ptrs_c(old), p, entry_c) {
+			if (((1U << i) & m->data_opts.rewrite_ptrs) &&
+			    (ptr = bch2_extent_has_ptr(old, p, bkey_i_to_s(insert))) &&
+			    !ptr->cached) {
+				bch2_extent_ptr_set_cached(bkey_i_to_s(insert), ptr);
+				rewrites_found |= 1U << i;
+			}
+			i++;
+		}
+
+		if (m->data_opts.rewrite_ptrs &&
+		    !rewrites_found &&
+		    bch2_bkey_durability(c, k) >= m->op.opts.data_replicas) {
+			trace_move_extent_fail2(m, k, bkey_i_to_s_c(&new->k_i), insert, "no rewrites found:");
+			goto nowork;
+		}
+
+		/*
+		 * A replica that we just wrote might conflict with a replica
+		 * that we want to keep, due to racing with another move:
+		 */
+restart_drop_conflicting_replicas:
+		extent_for_each_ptr(extent_i_to_s(new), ptr)
+			if ((ptr_c = bch2_bkey_has_device_c(bkey_i_to_s_c(insert), ptr->dev)) &&
+			    !ptr_c->cached) {
+				bch2_bkey_drop_ptr_noerror(bkey_i_to_s(&new->k_i), ptr);
+				goto restart_drop_conflicting_replicas;
+			}
+
+		if (!bkey_val_u64s(&new->k)) {
+			trace_move_extent_fail2(m, k, bkey_i_to_s_c(&new->k_i), insert, "new replicas conflicted:");
+			goto nowork;
+		}
+
+		/* Now, drop pointers that conflict with what we just wrote: */
+		extent_for_each_ptr_decode(extent_i_to_s(new), p, entry)
+			if ((ptr = bch2_bkey_has_device(bkey_i_to_s(insert), p.ptr.dev)))
+				bch2_bkey_drop_ptr_noerror(bkey_i_to_s(insert), ptr);
+
+		durability = bch2_bkey_durability(c, bkey_i_to_s_c(insert)) +
+			bch2_bkey_durability(c, bkey_i_to_s_c(&new->k_i));
+
+		/* Now, drop excess replicas: */
+restart_drop_extra_replicas:
+		bkey_for_each_ptr_decode(old.k, bch2_bkey_ptrs(bkey_i_to_s(insert)), p, entry) {
+			unsigned ptr_durability = bch2_extent_ptr_durability(c, &p);
+
+			if (!p.ptr.cached &&
+			    durability - ptr_durability >= m->op.opts.data_replicas) {
+				durability -= ptr_durability;
+
+				bch2_extent_ptr_set_cached(bkey_i_to_s(insert), &entry->ptr);
+				goto restart_drop_extra_replicas;
+			}
+		}
+
+		/* Finally, add the pointers we just wrote: */
+		extent_for_each_ptr_decode(extent_i_to_s(new), p, entry)
+			bch2_extent_ptr_decoded_append(insert, &p);
+
+		bch2_bkey_narrow_crcs(insert, (struct bch_extent_crc_unpacked) { 0 });
+		bch2_extent_normalize(c, bkey_i_to_s(insert));
+
+		ret = bch2_sum_sector_overwrites(trans, &iter, insert,
+						 &should_check_enospc,
+						 &i_sectors_delta,
+						 &disk_sectors_delta);
+		if (ret)
+			goto err;
+
+		if (disk_sectors_delta > (s64) op->res.sectors) {
+			ret = bch2_disk_reservation_add(c, &op->res,
+						disk_sectors_delta - op->res.sectors,
+						!should_check_enospc
+						? BCH_DISK_RESERVATION_NOFAIL : 0);
+			if (ret)
+				goto out;
+		}
+
+		next_pos = insert->k.p;
+
+		/*
+		 * Check for nonce offset inconsistency:
+		 * This is debug code - we've been seeing this bug rarely, and
+		 * it's been hard to reproduce, so this should give us some more
+		 * information when it does occur:
+		 */
+		struct printbuf err = PRINTBUF;
+		int invalid = bch2_bkey_invalid(c, bkey_i_to_s_c(insert), __btree_node_type(0, m->btree_id), 0, &err);
+		printbuf_exit(&err);
+
+		if (invalid) {
+			struct printbuf buf = PRINTBUF;
+
+			prt_str(&buf, "about to insert invalid key in data update path");
+			prt_str(&buf, "\nold: ");
+			bch2_bkey_val_to_text(&buf, c, old);
+			prt_str(&buf, "\nk:   ");
+			bch2_bkey_val_to_text(&buf, c, k);
+			prt_str(&buf, "\nnew: ");
+			bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(insert));
+
+			bch2_print_string_as_lines(KERN_ERR, buf.buf);
+			printbuf_exit(&buf);
+
+			bch2_fatal_error(c);
+			goto out;
+		}
+
+		if (trace_data_update_enabled()) {
+			struct printbuf buf = PRINTBUF;
+
+			prt_str(&buf, "\nold: ");
+			bch2_bkey_val_to_text(&buf, c, old);
+			prt_str(&buf, "\nk:   ");
+			bch2_bkey_val_to_text(&buf, c, k);
+			prt_str(&buf, "\nnew: ");
+			bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(insert));
+
+			trace_data_update(c, buf.buf);
+			printbuf_exit(&buf);
+		}
+
+		ret =   bch2_insert_snapshot_whiteouts(trans, m->btree_id,
+						k.k->p, bkey_start_pos(&insert->k)) ?:
+			bch2_insert_snapshot_whiteouts(trans, m->btree_id,
+						k.k->p, insert->k.p) ?:
+			bch2_bkey_set_needs_rebalance(c, insert,
+						      op->opts.background_target,
+						      op->opts.background_compression) ?:
+			bch2_trans_update(trans, &iter, insert,
+				BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE) ?:
+			bch2_trans_commit(trans, &op->res,
+				NULL,
+				BCH_TRANS_COMMIT_no_check_rw|
+				BCH_TRANS_COMMIT_no_enospc|
+				m->data_opts.btree_insert_flags);
+		if (!ret) {
+			bch2_btree_iter_set_pos(&iter, next_pos);
+
+			this_cpu_add(c->counters[BCH_COUNTER_move_extent_finish], new->k.size);
+			trace_move_extent_finish2(c, bkey_i_to_s_c(&new->k_i));
+		}
+err:
+		if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
+			ret = 0;
+		if (ret)
+			break;
+next:
+		while (bkey_ge(iter.pos, bch2_keylist_front(keys)->k.p)) {
+			bch2_keylist_pop_front(keys);
+			if (bch2_keylist_empty(keys))
+				goto out;
+		}
+		continue;
+nowork:
+		if (m->stats) {
+			BUG_ON(k.k->p.offset <= iter.pos.offset);
+			atomic64_inc(&m->stats->keys_raced);
+			atomic64_add(k.k->p.offset - iter.pos.offset,
+				     &m->stats->sectors_raced);
+		}
+
+		count_event(c, move_extent_fail);
+
+		bch2_btree_iter_advance(&iter);
+		goto next;
+	}
+out:
+	bch2_trans_iter_exit(trans, &iter);
+	bch2_bkey_buf_exit(&_insert, c);
+	bch2_bkey_buf_exit(&_new, c);
+	BUG_ON(bch2_err_matches(ret, BCH_ERR_transaction_restart));
+	return ret;
+}
+
+int bch2_data_update_index_update(struct bch_write_op *op)
+{
+	return bch2_trans_run(op->c, __bch2_data_update_index_update(trans, op));
+}
+
+void bch2_data_update_read_done(struct data_update *m,
+				struct bch_extent_crc_unpacked crc)
+{
+	/* write bio must own pages: */
+	BUG_ON(!m->op.wbio.bio.bi_vcnt);
+
+	m->op.crc = crc;
+	m->op.wbio.bio.bi_iter.bi_size = crc.compressed_size << 9;
+
+	closure_call(&m->op.cl, bch2_write, NULL, NULL);
+}
+
+void bch2_data_update_exit(struct data_update *update)
+{
+	struct bch_fs *c = update->op.c;
+	struct bkey_ptrs_c ptrs =
+		bch2_bkey_ptrs_c(bkey_i_to_s_c(update->k.k));
+
+	bkey_for_each_ptr(ptrs, ptr) {
+		if (c->opts.nocow_enabled)
+			bch2_bucket_nocow_unlock(&c->nocow_locks,
+						 PTR_BUCKET_POS(c, ptr), 0);
+		percpu_ref_put(&bch_dev_bkey_exists(c, ptr->dev)->ref);
+	}
+
+	bch2_bkey_buf_exit(&update->k, c);
+	bch2_disk_reservation_put(c, &update->op.res);
+	bch2_bio_free_pages_pool(c, &update->op.wbio.bio);
+}
+
+static void bch2_update_unwritten_extent(struct btree_trans *trans,
+				  struct data_update *update)
+{
+	struct bch_fs *c = update->op.c;
+	struct bio *bio = &update->op.wbio.bio;
+	struct bkey_i_extent *e;
+	struct write_point *wp;
+	struct closure cl;
+	struct btree_iter iter;
+	struct bkey_s_c k;
+	int ret;
+
+	closure_init_stack(&cl);
+	bch2_keylist_init(&update->op.insert_keys, update->op.inline_keys);
+
+	while (bio_sectors(bio)) {
+		unsigned sectors = bio_sectors(bio);
+
+		bch2_trans_iter_init(trans, &iter, update->btree_id, update->op.pos,
+				     BTREE_ITER_SLOTS);
+		ret = lockrestart_do(trans, ({
+			k = bch2_btree_iter_peek_slot(&iter);
+			bkey_err(k);
+		}));
+		bch2_trans_iter_exit(trans, &iter);
+
+		if (ret || !bch2_extents_match(k, bkey_i_to_s_c(update->k.k)))
+			break;
+
+		e = bkey_extent_init(update->op.insert_keys.top);
+		e->k.p = update->op.pos;
+
+		ret = bch2_alloc_sectors_start_trans(trans,
+				update->op.target,
+				false,
+				update->op.write_point,
+				&update->op.devs_have,
+				update->op.nr_replicas,
+				update->op.nr_replicas,
+				update->op.watermark,
+				0, &cl, &wp);
+		if (bch2_err_matches(ret, BCH_ERR_operation_blocked)) {
+			bch2_trans_unlock(trans);
+			closure_sync(&cl);
+			continue;
+		}
+
+		bch_err_fn_ratelimited(c, ret);
+
+		if (ret)
+			return;
+
+		sectors = min(sectors, wp->sectors_free);
+
+		bch2_key_resize(&e->k, sectors);
+
+		bch2_open_bucket_get(c, wp, &update->op.open_buckets);
+		bch2_alloc_sectors_append_ptrs(c, wp, &e->k_i, sectors, false);
+		bch2_alloc_sectors_done(c, wp);
+
+		bio_advance(bio, sectors << 9);
+		update->op.pos.offset += sectors;
+
+		extent_for_each_ptr(extent_i_to_s(e), ptr)
+			ptr->unwritten = true;
+		bch2_keylist_push(&update->op.insert_keys);
+
+		ret = __bch2_data_update_index_update(trans, &update->op);
+
+		bch2_open_buckets_put(c, &update->op.open_buckets);
+
+		if (ret)
+			break;
+	}
+
+	if (closure_nr_remaining(&cl) != 1) {
+		bch2_trans_unlock(trans);
+		closure_sync(&cl);
+	}
+}
+
+int bch2_extent_drop_ptrs(struct btree_trans *trans,
+			  struct btree_iter *iter,
+			  struct bkey_s_c k,
+			  struct data_update_opts data_opts)
+{
+	struct bch_fs *c = trans->c;
+	struct bkey_i *n;
+	int ret;
+
+	n = bch2_bkey_make_mut_noupdate(trans, k);
+	ret = PTR_ERR_OR_ZERO(n);
+	if (ret)
+		return ret;
+
+	while (data_opts.kill_ptrs) {
+		unsigned i = 0, drop = __fls(data_opts.kill_ptrs);
+		struct bch_extent_ptr *ptr;
+
+		bch2_bkey_drop_ptrs(bkey_i_to_s(n), ptr, i++ == drop);
+		data_opts.kill_ptrs ^= 1U << drop;
+	}
+
+	/*
+	 * If the new extent no longer has any pointers, bch2_extent_normalize()
+	 * will do the appropriate thing with it (turning it into a
+	 * KEY_TYPE_error key, or just a discard if it was a cached extent)
+	 */
+	bch2_extent_normalize(c, bkey_i_to_s(n));
+
+	/*
+	 * Since we're not inserting through an extent iterator
+	 * (BTREE_ITER_ALL_SNAPSHOTS iterators aren't extent iterators),
+	 * we aren't using the extent overwrite path to delete, we're
+	 * just using the normal key deletion path:
+	 */
+	if (bkey_deleted(&n->k) && !(iter->flags & BTREE_ITER_IS_EXTENTS))
+		n->k.size = 0;
+
+	return bch2_trans_relock(trans) ?:
+		bch2_trans_update(trans, iter, n, BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE) ?:
+		bch2_trans_commit(trans, NULL, NULL, BCH_TRANS_COMMIT_no_enospc);
+}
+
+int bch2_data_update_init(struct btree_trans *trans,
+			  struct btree_iter *iter,
+			  struct moving_context *ctxt,
+			  struct data_update *m,
+			  struct write_point_specifier wp,
+			  struct bch_io_opts io_opts,
+			  struct data_update_opts data_opts,
+			  enum btree_id btree_id,
+			  struct bkey_s_c k)
+{
+	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;
+	unsigned i, reserve_sectors = k.k->size * data_opts.extra_replicas;
+	unsigned ptrs_locked = 0;
+	int ret = 0;
+
+	bch2_bkey_buf_init(&m->k);
+	bch2_bkey_buf_reassemble(&m->k, c, k);
+	m->btree_id	= btree_id;
+	m->data_opts	= data_opts;
+	m->ctxt		= ctxt;
+	m->stats	= ctxt ? ctxt->stats : NULL;
+
+	bch2_write_op_init(&m->op, c, io_opts);
+	m->op.pos	= bkey_start_pos(k.k);
+	m->op.version	= k.k->version;
+	m->op.target	= data_opts.target;
+	m->op.write_point = wp;
+	m->op.nr_replicas = 0;
+	m->op.flags	|= BCH_WRITE_PAGES_STABLE|
+		BCH_WRITE_PAGES_OWNED|
+		BCH_WRITE_DATA_ENCODED|
+		BCH_WRITE_MOVE|
+		m->data_opts.write_flags;
+	m->op.compression_opt	= io_opts.background_compression ?: io_opts.compression;
+	m->op.watermark		= m->data_opts.btree_insert_flags & BCH_WATERMARK_MASK;
+
+	bkey_for_each_ptr(ptrs, ptr)
+		percpu_ref_get(&bch_dev_bkey_exists(c, ptr->dev)->ref);
+
+	unsigned durability_have = 0, durability_removing = 0;
+
+	i = 0;
+	bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
+		bool locked;
+
+		if (((1U << i) & m->data_opts.rewrite_ptrs)) {
+			BUG_ON(p.ptr.cached);
+
+			if (crc_is_compressed(p.crc))
+				reserve_sectors += k.k->size;
+
+			m->op.nr_replicas += bch2_extent_ptr_desired_durability(c, &p);
+			durability_removing += bch2_extent_ptr_desired_durability(c, &p);
+		} else if (!p.ptr.cached &&
+			   !((1U << i) & m->data_opts.kill_ptrs)) {
+			bch2_dev_list_add_dev(&m->op.devs_have, p.ptr.dev);
+			durability_have += bch2_extent_ptr_durability(c, &p);
+		}
+
+		/*
+		 * op->csum_type is normally initialized from the fs/file's
+		 * current options - but if an extent is encrypted, we require
+		 * that it stays encrypted:
+		 */
+		if (bch2_csum_type_is_encryption(p.crc.csum_type)) {
+			m->op.nonce	= p.crc.nonce + p.crc.offset;
+			m->op.csum_type = p.crc.csum_type;
+		}
+
+		if (p.crc.compression_type == BCH_COMPRESSION_TYPE_incompressible)
+			m->op.incompressible = true;
+
+		if (c->opts.nocow_enabled) {
+			if (ctxt) {
+				move_ctxt_wait_event(ctxt,
+						(locked = bch2_bucket_nocow_trylock(&c->nocow_locks,
+									  PTR_BUCKET_POS(c, &p.ptr), 0)) ||
+						(!atomic_read(&ctxt->read_sectors) &&
+						 !atomic_read(&ctxt->write_sectors)));
+
+				if (!locked)
+					bch2_bucket_nocow_lock(&c->nocow_locks,
+							       PTR_BUCKET_POS(c, &p.ptr), 0);
+			} else {
+				if (!bch2_bucket_nocow_trylock(&c->nocow_locks,
+							       PTR_BUCKET_POS(c, &p.ptr), 0)) {
+					ret = -BCH_ERR_nocow_lock_blocked;
+					goto err;
+				}
+			}
+			ptrs_locked |= (1U << i);
+		}
+
+		i++;
+	}
+
+	/*
+	 * If current extent durability is less than io_opts.data_replicas,
+	 * we're not trying to rereplicate the extent up to data_replicas here -
+	 * unless extra_replicas was specified
+	 *
+	 * Increasing replication is an explicit operation triggered by
+	 * rereplicate, currently, so that users don't get an unexpected -ENOSPC
+	 */
+	if (!(m->data_opts.write_flags & BCH_WRITE_CACHED) &&
+	    durability_have >= io_opts.data_replicas) {
+		m->data_opts.kill_ptrs |= m->data_opts.rewrite_ptrs;
+		m->data_opts.rewrite_ptrs = 0;
+		/* if iter == NULL, it's just a promote */
+		if (iter)
+			ret = bch2_extent_drop_ptrs(trans, iter, k, m->data_opts);
+		goto done;
+	}
+
+	m->op.nr_replicas = min(durability_removing, io_opts.data_replicas - durability_have) +
+		m->data_opts.extra_replicas;
+	m->op.nr_replicas_required = m->op.nr_replicas;
+
+	BUG_ON(!m->op.nr_replicas);
+
+	if (reserve_sectors) {
+		ret = bch2_disk_reservation_add(c, &m->op.res, reserve_sectors,
+				m->data_opts.extra_replicas
+				? 0
+				: BCH_DISK_RESERVATION_NOFAIL);
+		if (ret)
+			goto err;
+	}
+
+	if (bkey_extent_is_unwritten(k)) {
+		bch2_update_unwritten_extent(trans, m);
+		goto done;
+	}
+
+	return 0;
+err:
+	i = 0;
+	bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
+		if ((1U << i) & ptrs_locked)
+			bch2_bucket_nocow_unlock(&c->nocow_locks,
+						 PTR_BUCKET_POS(c, &p.ptr), 0);
+		percpu_ref_put(&bch_dev_bkey_exists(c, p.ptr.dev)->ref);
+		i++;
+	}
+
+	bch2_bkey_buf_exit(&m->k, c);
+	bch2_bio_free_pages_pool(c, &m->op.wbio.bio);
+	return ret;
+done:
+	bch2_data_update_exit(m);
+	return ret ?: -BCH_ERR_data_update_done;
+}
+
+void bch2_data_update_opts_normalize(struct bkey_s_c k, struct data_update_opts *opts)
+{
+	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
+	unsigned i = 0;
+
+	bkey_for_each_ptr(ptrs, ptr) {
+		if ((opts->rewrite_ptrs & (1U << i)) && ptr->cached) {
+			opts->kill_ptrs |= 1U << i;
+			opts->rewrite_ptrs ^= 1U << i;
+		}
+
+		i++;
+	}
+}