bcachefs: Second layer of refcounting for new stripes

This will be used for move writes, which will be waiting until the
stripe is created to do the index update. They need to prevent the
stripe from being reclaimed until their index update is done, so we need
another refcount that just keeps the stripe open.

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

# Conflicts:
#	fs/bcachefs/ec.c
#	fs/bcachefs/io.c

1 files changed, 26 insertions, 10 deletions

diff --git a/fs/bcachefs/ec.h b/fs/bcachefs/ec.h
index d112aea9ec56..8f777a37e43d 100644
--- a/fs/bcachefs/ec.h
+++ b/fs/bcachefs/ec.h
@@ -143,6 +143,12 @@ struct ec_stripe_buf {
 
 struct ec_stripe_head;
 
+enum ec_stripe_ref {
+	STRIPE_REF_io,
+	STRIPE_REF_stripe,
+	STRIPE_REF_NR
+};
+
 struct ec_stripe_new {
 	struct bch_fs		*c;
 	struct ec_stripe_head	*h;
@@ -154,8 +160,7 @@ struct ec_stripe_new {
 
 	struct closure		iodone;
 
-	/* counts in flight writes, stripe is created when pin == 0 */
-	atomic_t		pin;
+	atomic_t		ref[STRIPE_REF_NR];
 
 	int			err;
 
@@ -213,19 +218,30 @@ void bch2_stripes_heap_insert(struct bch_fs *, struct stripe *, size_t);
 
 void bch2_do_stripe_deletes(struct bch_fs *);
 void bch2_ec_do_stripe_creates(struct bch_fs *);
+void bch2_ec_stripe_new_free(struct bch_fs *, struct ec_stripe_new *);
 
-static inline void ec_stripe_new_get(struct ec_stripe_new *s)
+static inline void ec_stripe_new_get(struct ec_stripe_new *s,
+				     enum ec_stripe_ref ref)
 {
-	atomic_inc(&s->pin);
+	atomic_inc(&s->ref[ref]);
 }
 
-static inline void ec_stripe_new_put(struct bch_fs *c, struct ec_stripe_new *s)
+static inline void ec_stripe_new_put(struct bch_fs *c, struct ec_stripe_new *s,
+				     enum ec_stripe_ref ref)
 {
-	BUG_ON(atomic_read(&s->pin) <= 0);
-	BUG_ON(!s->err && !s->idx);
-
-	if (atomic_dec_and_test(&s->pin))
-		bch2_ec_do_stripe_creates(c);
+	BUG_ON(atomic_read(&s->ref[ref]) <= 0);
+
+	if (atomic_dec_and_test(&s->ref[ref]))
+		switch (ref) {
+		case STRIPE_REF_stripe:
+			bch2_ec_stripe_new_free(c, s);
+			break;
+		case STRIPE_REF_io:
+			bch2_ec_do_stripe_creates(c);
+			break;
+		default:
+			unreachable();
+		}
 }
 
 void bch2_ec_stop_dev(struct bch_fs *, struct bch_dev *);