bcachefs: bch2_subvolume_get()

Factor out a little helper.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

fs/bcachefs/dirent.c

@@ -191,34 +191,15 @@ int __bch2_dirent_read_target(struct btree_trans *trans,
 	if (likely(d.v->d_type != DT_SUBVOL)) {
 		*inum = le64_to_cpu(d.v->d_inum);
 	} else {
-		struct btree_iter iter;
-		struct bkey_s_c k;
-		struct bkey_s_c_subvolume s;
+		struct bch_subvolume s;
 		int ret;
 
 		*subvol = le64_to_cpu(d.v->d_inum);
-		bch2_trans_iter_init(trans, &iter, BTREE_ID_subvolumes,
-				     POS(0, *subvol),
-				     BTREE_ITER_CACHED);
-		k = bch2_btree_iter_peek_slot(&iter);
-		ret = bkey_err(k);
-		if (ret)
-			goto err;
-
-		if (k.k->type != KEY_TYPE_subvolume) {
-			ret = -ENOENT;
-			goto err;
-		}
 
-		s = bkey_s_c_to_subvolume(k);
-		*snapshot	= le32_to_cpu(s.v->snapshot);
-		*inum		= le64_to_cpu(s.v->inode);
-err:
-		if (ret == -ENOENT && !is_fsck)
-			bch2_fs_inconsistent(trans->c, "pointer to missing subvolume %u",
-					     *subvol);
+		ret = bch2_subvolume_get(trans, *subvol, !is_fsck, BTREE_ITER_CACHED, &s);
 
-		bch2_trans_iter_exit(trans, &iter);
+		*snapshot	= le32_to_cpu(s.snapshot);
+		*inum		= le64_to_cpu(s.inode);
 	}
 
 	return ret;

fs/bcachefs/fs-common.c

@@ -67,26 +67,14 @@ int bch2_create_trans(struct btree_trans *trans,
 
 		if (!snapshot_src.inum) {
 			/* Inode wasn't specified, just snapshot: */
-			struct btree_iter subvol_iter;
-			struct bkey_s_c k;
-
-			bch2_trans_iter_init(trans, &subvol_iter, BTREE_ID_subvolumes,
-					     POS(0, snapshot_src.subvol), 0);
-			k = bch2_btree_iter_peek_slot(&subvol_iter);
-
-			ret = bkey_err(k);
-			if (!ret && k.k->type != KEY_TYPE_subvolume) {
-				bch_err(c, "subvolume %u not found",
-					snapshot_src.subvol);
-				ret = -ENOENT;
-			}
-
-			if (!ret)
-				snapshot_src.inum = le64_to_cpu(bkey_s_c_to_subvolume(k).v->inode);
-			bch2_trans_iter_exit(trans, &subvol_iter);
+			struct bch_subvolume s;
 
+			ret = bch2_subvolume_get(trans, snapshot_src.subvol, true,
+						 BTREE_ITER_CACHED, &s);
 			if (ret)
 				goto err;
+
+			snapshot_src.inum = le64_to_cpu(s.inode);
 		}
 
 		ret = bch2_inode_peek(trans, &inode_iter, new_inode, snapshot_src,

fs/bcachefs/fsck.c

@@ -103,29 +103,14 @@ static int snapshot_lookup_subvol(struct btree_trans *trans, u32 snapshot,
 static int __subvol_lookup(struct btree_trans *trans, u32 subvol,
 			   u32 *snapshot, u64 *inum)
 {
-	struct btree_iter iter;
-	struct bkey_s_c k;
+	struct bch_subvolume s;
 	int ret;
 
-	bch2_trans_iter_init(trans, &iter, BTREE_ID_subvolumes,
-			     POS(0, subvol), 0);
-	k = bch2_btree_iter_peek_slot(&iter);
-	ret = bkey_err(k);
-	if (ret)
-		goto err;
+	ret = bch2_subvolume_get(trans, subvol, false, 0, &s);
 
-	if (k.k->type != KEY_TYPE_subvolume) {
-		bch_err(trans->c, "subvolume %u not fonud", subvol);
-		ret = -ENOENT;
-		goto err;
-	}
-
-	*snapshot = le32_to_cpu(bkey_s_c_to_subvolume(k).v->snapshot);
-	*inum = le64_to_cpu(bkey_s_c_to_subvolume(k).v->inode);
-err:
-	bch2_trans_iter_exit(trans, &iter);
+	*snapshot = le32_to_cpu(s.snapshot);
+	*inum = le64_to_cpu(s.inode);
 	return ret;
-
 }
 
 static int subvol_lookup(struct btree_trans *trans, u32 subvol,

fs/bcachefs/subvolume.c

@@ -89,23 +89,6 @@ int bch2_mark_snapshot(struct bch_fs *c,
 	return 0;
 }
 
-static int subvol_lookup(struct btree_trans *trans, unsigned id, struct bch_subvolume *s)
-{
-	struct btree_iter iter;
-	struct bkey_s_c k;
-	int ret;
-
-	bch2_trans_iter_init(trans, &iter, BTREE_ID_subvolumes, POS(0, id), 0);
-	k = bch2_btree_iter_peek_slot(&iter);
-	ret = bkey_err(k) ?: k.k->type == KEY_TYPE_subvolume ? 0 : -ENOENT;
-
-	if (!ret)
-		*s = *bkey_s_c_to_subvolume(k).v;
-
-	bch2_trans_iter_exit(trans, &iter);
-	return ret;
-}
-
 static int snapshot_lookup(struct btree_trans *trans, u32 id,
 			   struct bch_snapshot *s)
 {
@@ -195,7 +178,7 @@ static int bch2_snapshot_check(struct btree_trans *trans,
 	int ret;
 
 	id = le32_to_cpu(s.v->subvol);
-	ret = lockrestart_do(trans, subvol_lookup(trans, id, &subvol));
+	ret = lockrestart_do(trans, bch2_subvolume_get(trans, id, 0, false, &subvol));
 	if (ret == -ENOENT)
 		bch_err(trans->c, "snapshot node %llu has nonexistent subvolume %u",
 			s.k->p.offset, id);
@@ -798,34 +781,44 @@ void bch2_subvolume_to_text(struct printbuf *out, struct bch_fs *c,
 	       le32_to_cpu(s.v->snapshot));
 }
 
-int bch2_subvolume_get_snapshot(struct btree_trans *trans, u32 subvol,
-				u32 *snapid)
+int bch2_subvolume_get(struct btree_trans *trans, unsigned subvol,
+		       bool inconsistent_if_not_found,
+		       int iter_flags,
+		       struct bch_subvolume *s)
 {
 	struct btree_iter iter;
 	struct bkey_s_c k;
 	int ret;
 
-	bch2_trans_iter_init(trans, &iter, BTREE_ID_subvolumes,
-			     POS(0, subvol),
-			     BTREE_ITER_CACHED|
-			     BTREE_ITER_WITH_UPDATES);
+	bch2_trans_iter_init(trans, &iter, BTREE_ID_subvolumes, POS(0, subvol),
+			     iter_flags);
 	k = bch2_btree_iter_peek_slot(&iter);
-	ret = bkey_err(k);
-	if (ret)
-		goto err;
+	ret = bkey_err(k) ?: k.k->type == KEY_TYPE_subvolume ? 0 : -ENOENT;
 
-	if (k.k->type != KEY_TYPE_subvolume) {
+	if (ret == -ENOENT && inconsistent_if_not_found)
 		bch2_fs_inconsistent(trans->c, "missing subvolume %u", subvol);
-		ret = -EIO;
-		goto err;
-	}
+	if (!ret)
+		*s = *bkey_s_c_to_subvolume(k).v;
 
-	*snapid = le32_to_cpu(bkey_s_c_to_subvolume(k).v->snapshot);
-err:
 	bch2_trans_iter_exit(trans, &iter);
 	return ret;
 }
 
+int bch2_subvolume_get_snapshot(struct btree_trans *trans, u32 subvol,
+				u32 *snapid)
+{
+	struct bch_subvolume s;
+	int ret;
+
+	ret = bch2_subvolume_get(trans, subvol, true,
+				 BTREE_ITER_CACHED|
+				 BTREE_ITER_WITH_UPDATES,
+				 &s);
+
+	*snapid = le32_to_cpu(s.snapshot);
+	return ret;
+}
+
 /* XXX: mark snapshot id for deletion, walk btree and delete: */
 int bch2_subvolume_delete(struct btree_trans *trans, u32 subvolid,
 			  int deleting_snapshot)

fs/bcachefs/subvolume.h

@@ -104,6 +104,8 @@ void bch2_subvolume_to_text(struct printbuf *, struct bch_fs *, struct bkey_s_c)
 	.val_to_text	= bch2_subvolume_to_text,		\
 }
 
+int bch2_subvolume_get(struct btree_trans *, unsigned,
+		       bool, int, struct bch_subvolume *);
 int bch2_subvolume_get_snapshot(struct btree_trans *, u32, u32 *);
 
 int bch2_subvolume_delete(struct btree_trans *, u32, int);