bcachefs: Account for stripe parity sectors separately

Instead of trying to charge EC parity to the data within the stripe
(which is subject to rounding errors), let's charge it to the stripe
itself. It should also make -ENOSPC issues easier to deal with if we
charge for parity blocks up front, and means we can also make more fine
grained accounting available to the user.

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

1 files changed, 28 insertions, 3 deletions

diff --git a/fs/bcachefs/ec.c b/fs/bcachefs/ec.c
index c6d6f23d3f24..e5033b392432 100644
--- a/fs/bcachefs/ec.c
+++ b/fs/bcachefs/ec.c
@@ -343,12 +343,17 @@ static void ec_block_io(struct bch_fs *c, struct ec_stripe_buf *buf,
 	unsigned offset = 0, bytes = buf->size << 9;
 	struct bch_extent_ptr *ptr = &v->ptrs[idx];
 	struct bch_dev *ca = bch_dev_bkey_exists(c, ptr->dev);
+	enum bch_data_type data_type = idx < buf->key.v.nr_blocks - buf->key.v.nr_redundant
+		? BCH_DATA_user
+		: BCH_DATA_parity;
 
 	if (!bch2_dev_get_ioref(ca, rw)) {
 		clear_bit(idx, buf->valid);
 		return;
 	}
 
+	this_cpu_add(ca->io_done->sectors[rw][data_type], buf->size);
+
 	while (offset < bytes) {
 		unsigned nr_iovecs = min_t(size_t, BIO_MAX_VECS,
 					   DIV_ROUND_UP(bytes, PAGE_SIZE));
@@ -670,6 +675,7 @@ static void ec_stripe_delete_work(struct work_struct *work)
 /* stripe creation: */
 
 static int ec_stripe_bkey_insert(struct bch_fs *c,
+				 struct ec_stripe_new *s,
 				 struct bkey_i_stripe *stripe)
 {
 	struct btree_trans trans;
@@ -711,7 +717,7 @@ found_slot:
 
 	bch2_trans_update(&trans, iter, &stripe->k_i, 0);
 
-	ret = bch2_trans_commit(&trans, NULL, NULL,
+	ret = bch2_trans_commit(&trans, &s->res, NULL,
 				BTREE_INSERT_NOFAIL);
 err:
 	bch2_trans_iter_put(&trans, iter);
@@ -858,8 +864,8 @@ static void ec_stripe_create(struct ec_stripe_new *s)
 
 	ret = s->existing_stripe
 		? bch2_btree_insert(c, BTREE_ID_EC, &s->stripe.key.k_i,
-				    NULL, NULL, BTREE_INSERT_NOFAIL)
-		: ec_stripe_bkey_insert(c, &s->stripe.key);
+				    &s->res, NULL, BTREE_INSERT_NOFAIL)
+		: ec_stripe_bkey_insert(c, s, &s->stripe.key);
 	if (ret) {
 		bch_err(c, "error creating stripe: error creating stripe key");
 		goto err_put_writes;
@@ -886,6 +892,8 @@ static void ec_stripe_create(struct ec_stripe_new *s)
 err_put_writes:
 	percpu_ref_put(&c->writes);
 err:
+	bch2_disk_reservation_put(c, &s->res);
+
 	open_bucket_for_each(c, &s->blocks, ob, i) {
 		ob->ec = NULL;
 		__bch2_open_bucket_put(c, ob);
@@ -1325,6 +1333,7 @@ struct ec_stripe_head *bch2_ec_stripe_head_get(struct bch_fs *c,
 	struct open_bucket *ob;
 	unsigned i, data_idx = 0;
 	s64 idx;
+	int ret;
 
 	closure_init_stack(&cl);
 
@@ -1356,6 +1365,22 @@ struct ec_stripe_head *bch2_ec_stripe_head_get(struct bch_fs *c,
 				}
 		}
 
+		if (!h->s->existing_stripe &&
+		    !h->s->res.sectors) {
+			ret = bch2_disk_reservation_get(c, &h->s->res,
+							h->blocksize,
+							h->s->nr_parity, 0);
+			if (ret) {
+				/* What should we do here? */
+				bch_err(c, "unable to create new stripe: %i", ret);
+				bch2_ec_stripe_head_put(c, h);
+				h = NULL;
+				goto out;
+
+			}
+
+		}
+
 		if (new_stripe_alloc_buckets(c, h)) {
 			bch2_ec_stripe_head_put(c, h);
 			h = NULL;