bcachefs: Improve bch2_bkey_make_mut()

bch2_bkey_make_mut() now takes the bkey_s_c by reference and points it
at the new, mutable key.

This helps in some fsck paths that may have multiple repair operations
on the same key.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/btree_gc.c

@@ -1585,7 +1585,7 @@ static int bch2_gc_write_reflink_key(struct btree_trans *trans,
 			"  should be %u",
 			(bch2_bkey_val_to_text(&buf, c, k), buf.buf),
 			r->refcount)) {
-		struct bkey_i *new = bch2_bkey_make_mut(trans, iter, k, 0);
+		struct bkey_i *new = bch2_bkey_make_mut(trans, iter, &k, 0);
 
 		ret = PTR_ERR_OR_ZERO(new);
 		if (ret)
@@ -1913,7 +1913,7 @@ static int gc_btree_gens_key(struct btree_trans *trans,
 	percpu_up_read(&c->mark_lock);
 	return 0;
 update:
-	u = bch2_bkey_make_mut(trans, iter, k, 0);
+	u = bch2_bkey_make_mut(trans, iter, &k, 0);
 	ret = PTR_ERR_OR_ZERO(u);
 	if (ret)
 		return ret;

fs/bcachefs/btree_update.h

@@ -241,10 +241,10 @@ static inline struct bkey_i *bch2_bkey_make_mut_noupdate(struct btree_trans *tra
 				KEY_TYPE_##_type, sizeof(struct bkey_i_##_type)))
 
 static inline struct bkey_i *__bch2_bkey_make_mut(struct btree_trans *trans, struct btree_iter *iter,
-					struct bkey_s_c k, unsigned flags,
+					struct bkey_s_c *k, unsigned flags,
 					unsigned type, unsigned min_bytes)
 {
-	struct bkey_i *mut = __bch2_bkey_make_mut_noupdate(trans, k, type, min_bytes);
+	struct bkey_i *mut = __bch2_bkey_make_mut_noupdate(trans, *k, type, min_bytes);
 	int ret;
 
 	if (IS_ERR(mut))
@@ -253,11 +253,13 @@ static inline struct bkey_i *__bch2_bkey_make_mut(struct btree_trans *trans, str
 	ret = bch2_trans_update(trans, iter, mut, flags);
 	if (ret)
 		return ERR_PTR(ret);
+
+	*k = bkey_i_to_s_c(mut);
 	return mut;
 }
 
 static inline struct bkey_i *bch2_bkey_make_mut(struct btree_trans *trans, struct btree_iter *iter,
-						struct bkey_s_c k, unsigned flags)
+						struct bkey_s_c *k, unsigned flags)
 {
 	return __bch2_bkey_make_mut(trans, iter, k, flags, 0, 0);
 }

fs/bcachefs/migrate.c

@@ -49,7 +49,7 @@ static int bch2_dev_usrdata_drop_key(struct btree_trans *trans,
 	if (!bch2_bkey_has_device_c(k, dev_idx))
 		return 0;
 
-	n = bch2_bkey_make_mut(trans, iter, k, BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE);
+	n = bch2_bkey_make_mut(trans, iter, &k, BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE);
 	ret = PTR_ERR_OR_ZERO(n);
 	if (ret)
 		return ret;

fs/bcachefs/subvolume.c

@@ -385,7 +385,7 @@ static int check_snapshot_tree(struct btree_trans *trans,
 		if (ret)
 			goto err;
 
-		u = bch2_bkey_make_mut_typed(trans, iter, k, 0, snapshot_tree);
+		u = bch2_bkey_make_mut_typed(trans, iter, &k, 0, snapshot_tree);
 		ret = PTR_ERR_OR_ZERO(u);
 		if (ret)
 			goto err;
@@ -473,7 +473,7 @@ static int snapshot_tree_ptr_repair(struct btree_trans *trans,
 		return ret;
 
 	if (ret || le32_to_cpu(s_t.root_snapshot) != root_id) {
-		u = bch2_bkey_make_mut_typed(trans, &root_iter, root.s_c, 0, snapshot);
+		u = bch2_bkey_make_mut_typed(trans, &root_iter, &root.s_c, 0, snapshot);
 		ret =   PTR_ERR_OR_ZERO(u) ?:
 			snapshot_tree_create(trans, root_id,
 				bch2_snapshot_tree_oldest_subvol(c, root_id),
@@ -487,7 +487,7 @@ static int snapshot_tree_ptr_repair(struct btree_trans *trans,
 	}
 
 	if (s->k->p.snapshot != root_id) {
-		u = bch2_bkey_make_mut_typed(trans, iter, s->s_c, 0, snapshot);
+		u = bch2_bkey_make_mut_typed(trans, iter, &s->s_c, 0, snapshot);
 		ret = PTR_ERR_OR_ZERO(u);
 		if (ret)
 			goto err;
@@ -677,7 +677,7 @@ static int check_subvol(struct btree_trans *trans,
 				"subvolume %llu is not set as snapshot but is not master subvolume",
 				k.k->p.offset)) {
 			struct bkey_i_subvolume *s =
-				bch2_bkey_make_mut_typed(trans, iter, subvol.s_c, 0, subvolume);
+				bch2_bkey_make_mut_typed(trans, iter, &subvol.s_c, 0, subvolume);
 			ret = PTR_ERR_OR_ZERO(s);
 			if (ret)
 				return ret;
@@ -1249,7 +1249,7 @@ static int bch2_subvolume_reparent(struct btree_trans *trans,
 	    le32_to_cpu(bkey_s_c_to_subvolume(k).v->parent) != old_parent)
 		return 0;
 
-	s = bch2_bkey_make_mut_typed(trans, iter, k, 0, subvolume);
+	s = bch2_bkey_make_mut_typed(trans, iter, &k, 0, subvolume);
 	ret = PTR_ERR_OR_ZERO(s);
 	if (ret)
 		return ret;