bcachefs: Add write buffer flush param to backpointer_get_key()

In an upcoming patch bch2_backpointer_get_key() will be repairing when
it finds a dangling backpointer; it will need to flush the btree write
buffer before it can definitively say there's an error.

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

4 files changed, 26 insertions, 13 deletions

diff --git a/fs/bcachefs/backpointers.c b/fs/bcachefs/backpointers.c
index 98d89133fc75..d2f0b3140983 100644
--- a/fs/bcachefs/backpointers.c
+++ b/fs/bcachefs/backpointers.c
@@ -218,7 +218,8 @@ static void backpointer_target_not_found(struct btree_trans *trans,
 struct bkey_s_c bch2_backpointer_get_key(struct btree_trans *trans,
 					 struct bkey_s_c_backpointer bp,
 					 struct btree_iter *iter,
-					 unsigned iter_flags)
+					 unsigned iter_flags,
+					 struct bkey_buf *last_flushed)
 {
 	struct bch_fs *c = trans->c;
 
@@ -245,7 +246,7 @@ struct bkey_s_c bch2_backpointer_get_key(struct btree_trans *trans,
 		backpointer_target_not_found(trans, bp, k);
 		return bkey_s_c_null;
 	} else {
-		struct btree *b = bch2_backpointer_get_node(trans, bp, iter);
+		struct btree *b = bch2_backpointer_get_node(trans, bp, iter, last_flushed);
 
 		if (IS_ERR_OR_NULL(b)) {
 			bch2_trans_iter_exit(trans, iter);
@@ -257,7 +258,8 @@ struct bkey_s_c bch2_backpointer_get_key(struct btree_trans *trans,
 
 struct btree *bch2_backpointer_get_node(struct btree_trans *trans,
 					struct bkey_s_c_backpointer bp,
-					struct btree_iter *iter)
+					struct btree_iter *iter,
+					struct bkey_buf *last_flushed)
 {
 	struct bch_fs *c = trans->c;
 
@@ -486,7 +488,7 @@ check_existing_bp:
 	struct bkey_s_c_backpointer other_bp = bkey_s_c_to_backpointer(bp_k);
 
 	struct bkey_s_c other_extent =
-		bch2_backpointer_get_key(trans, other_bp, &other_extent_iter, 0);
+		bch2_backpointer_get_key(trans, other_bp, &other_extent_iter, 0, &s->last_flushed);
 	ret = bkey_err(other_extent);
 	if (ret == -BCH_ERR_backpointer_to_overwritten_btree_node)
 		ret = 0;
@@ -866,7 +868,7 @@ static int check_one_backpointer(struct btree_trans *trans,
 		return 0;
 
 	struct btree_iter iter;
-	struct bkey_s_c k = bch2_backpointer_get_key(trans, bp, &iter, 0);
+	struct bkey_s_c k = bch2_backpointer_get_key(trans, bp, &iter, 0, last_flushed);
 	int ret = bkey_err(k);
 	if (ret == -BCH_ERR_backpointer_to_overwritten_btree_node)
 		return 0;
diff --git a/fs/bcachefs/backpointers.h b/fs/bcachefs/backpointers.h
index 65ede8adbc36..060dad1521ee 100644
--- a/fs/bcachefs/backpointers.h
+++ b/fs/bcachefs/backpointers.h
@@ -158,10 +158,11 @@ static inline void bch2_extent_ptr_to_bp(struct bch_fs *c,
 	};
 }
 
+struct bkey_buf;
 struct bkey_s_c bch2_backpointer_get_key(struct btree_trans *, struct bkey_s_c_backpointer,
-					 struct btree_iter *, unsigned);
+					 struct btree_iter *, unsigned, struct bkey_buf *);
 struct btree *bch2_backpointer_get_node(struct btree_trans *, struct bkey_s_c_backpointer,
-					struct btree_iter *);
+					struct btree_iter *, struct bkey_buf *);
 
 int bch2_check_btree_backpointers(struct bch_fs *);
 int bch2_check_extents_to_backpointers(struct bch_fs *);
diff --git a/fs/bcachefs/ec.c b/fs/bcachefs/ec.c
index 3e7e41cd8380..d2a5e76e6479 100644
--- a/fs/bcachefs/ec.c
+++ b/fs/bcachefs/ec.c
@@ -1265,7 +1265,8 @@ static int ec_stripe_update_extent(struct btree_trans *trans,
 				   struct bch_dev *ca,
 				   struct bpos bucket, u8 gen,
 				   struct ec_stripe_buf *s,
-				   struct bkey_s_c_backpointer bp)
+				   struct bkey_s_c_backpointer bp,
+				   struct bkey_buf *last_flushed)
 {
 	struct bch_stripe *v = &bkey_i_to_stripe(&s->key)->v;
 	struct bch_fs *c = trans->c;
@@ -1282,7 +1283,7 @@ static int ec_stripe_update_extent(struct btree_trans *trans,
 		struct btree_iter node_iter;
 		struct btree *b;
 
-		b = bch2_backpointer_get_node(trans, bp, &node_iter);
+		b = bch2_backpointer_get_node(trans, bp, &node_iter, last_flushed);
 		bch2_trans_iter_exit(trans, &node_iter);
 
 		if (!b)
@@ -1296,7 +1297,7 @@ static int ec_stripe_update_extent(struct btree_trans *trans,
 		return -EIO;
 	}
 
-	k = bch2_backpointer_get_key(trans, bp, &iter, BTREE_ITER_intent);
+	k = bch2_backpointer_get_key(trans, bp, &iter, BTREE_ITER_intent, last_flushed);
 	ret = bkey_err(k);
 	if (ret)
 		return ret;
@@ -1363,6 +1364,10 @@ static int ec_stripe_update_bucket(struct btree_trans *trans, struct ec_stripe_b
 
 	struct bpos bucket_pos = PTR_BUCKET_POS(ca, &ptr);
 
+	struct bkey_buf last_flushed;
+	bch2_bkey_buf_init(&last_flushed);
+	bkey_init(&last_flushed.k->k);
+
 	ret = for_each_btree_key_max_commit(trans, bp_iter, BTREE_ID_backpointers,
 			bucket_pos_to_bp_start(ca, bucket_pos),
 			bucket_pos_to_bp_end(ca, bucket_pos), 0, bp_k,
@@ -1376,9 +1381,10 @@ static int ec_stripe_update_bucket(struct btree_trans *trans, struct ec_stripe_b
 			continue;
 
 		ec_stripe_update_extent(trans, ca, bucket_pos, ptr.gen, s,
-					bkey_s_c_to_backpointer(bp_k));
+					bkey_s_c_to_backpointer(bp_k), &last_flushed);
 	}));
 
+	bch2_bkey_buf_exit(&last_flushed, c);
 	bch2_dev_put(ca);
 	return ret;
 }
diff --git a/fs/bcachefs/move.c b/fs/bcachefs/move.c
index 6d38afcaaaab..184620d5a3b4 100644
--- a/fs/bcachefs/move.c
+++ b/fs/bcachefs/move.c
@@ -677,6 +677,7 @@ int bch2_evacuate_bucket(struct moving_context *ctxt,
 	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);
@@ -685,6 +686,8 @@ int bch2_evacuate_bucket(struct moving_context *ctxt,
 
 	trace_bucket_evacuate(c, &bucket);
 
+	bch2_bkey_buf_init(&last_flushed);
+	bkey_init(&last_flushed.k->k);
 	bch2_bkey_buf_init(&sk);
 
 	/*
@@ -726,7 +729,7 @@ int bch2_evacuate_bucket(struct moving_context *ctxt,
 		struct bkey_s_c_backpointer bp = bkey_s_c_to_backpointer(k);
 
 		if (!bp.v->level) {
-			k = bch2_backpointer_get_key(trans, bp, &iter, 0);
+			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;
@@ -784,7 +787,7 @@ int bch2_evacuate_bucket(struct moving_context *ctxt,
 		} else {
 			struct btree *b;
 
-			b = bch2_backpointer_get_node(trans, bp, &iter);
+			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;
@@ -822,6 +825,7 @@ 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;
 }