diff --git a/.github/dependabot.yml b/.github/dependabot.yml
index b444581..1dff6a2 100644
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@@ -9,3 +9,7 @@ updates:
     directory: "/" # Location of package manifests
     schedule:
       interval: "daily"
+  - package-ecosystem: "github-actions" # See documentation for possible values
+    directory: "/" # Location of package manifests
+    schedule:
+      interval: "daily"
\ No newline at end of file
diff --git a/.github/workflows/go.yml b/.github/workflows/go.yml
index 30ece3c..29540be 100644
--- a/.github/workflows/go.yml
+++ b/.github/workflows/go.yml
@@ -58,7 +58,6 @@ jobs:
       with:
         chart: true
         amend: true
-        reuse-go: true
       if: |
         github.event_name == 'push' &&
         matrix.os == 'ubuntu-latest'
diff --git a/const.go b/const.go
index 5c46934..01c3451 100644
--- a/const.go
+++ b/const.go
@@ -176,10 +176,11 @@ const (
 type FunctionFlag uint32
 
 const (
-	DETERMINISTIC FunctionFlag = 0x000000800
-	DIRECTONLY    FunctionFlag = 0x000080000
-	SUBTYPE       FunctionFlag = 0x000100000
-	INNOCUOUS     FunctionFlag = 0x000200000
+	DETERMINISTIC  FunctionFlag = 0x000000800
+	DIRECTONLY     FunctionFlag = 0x000080000
+	SUBTYPE        FunctionFlag = 0x000100000
+	INNOCUOUS      FunctionFlag = 0x000200000
+	RESULT_SUBTYPE FunctionFlag = 0x001000000
 )
 
 // StmtStatus name counter values associated with the [Stmt.Status] method.
diff --git a/ext/array/array.go b/ext/array/array.go
index 41eced8..a43c24d 100644
--- a/ext/array/array.go
+++ b/ext/array/array.go
@@ -1,4 +1,6 @@
 // Package array provides the array table-valued SQL function.
+//
+// https://sqlite.org/carray.html
 package array
 
 import (
@@ -11,8 +13,6 @@ import (
 // Register registers the array single-argument, table-valued SQL function.
 // The argument must be an [sqlite3.Pointer] to a Go slice or array
 // of ints, floats, bools, strings or blobs.
-//
-// https://sqlite.org/carray.html
 func Register(db *sqlite3.Conn) {
 	sqlite3.CreateModule[array](db, "array", nil,
 		func(db *sqlite3.Conn, _, _, _ string, _ ...string) (array, error) {
diff --git a/ext/fileio/fileio.go b/ext/fileio/fileio.go
index 652d22c..311dc9d 100644
--- a/ext/fileio/fileio.go
+++ b/ext/fileio/fileio.go
@@ -1,3 +1,6 @@
+// Package fileio provides SQL functions to read and write files.
+//
+// https://sqlite.org/src/doc/tip/ext/misc/fileio.c
 package fileio
 
 import (
@@ -9,14 +12,25 @@ import (
 	"github.com/ncruces/go-sqlite3"
 )
 
+// Register registers SQL functions readfile, writefile, lsmode,
+// and the eponymous virtual table fsdir.
 func Register(db *sqlite3.Conn) {
+	RegisterFS(db, nil)
+}
+
+// Register registers SQL functions readfile, lsmode,
+// and the eponymous virtual table fsdir;
+// fs will be used to read files and list directories.
+func RegisterFS(db *sqlite3.Conn, fs fs.FS) {
 	db.CreateFunction("lsmode", 1, 0, lsmode)
-	db.CreateFunction("readfile", 1, sqlite3.DIRECTONLY, readfile)
-	db.CreateFunction("writefile", -1, sqlite3.DIRECTONLY, writefile)
+	db.CreateFunction("readfile", 1, sqlite3.DIRECTONLY, readfile(fs))
+	if fs == nil {
+		db.CreateFunction("writefile", -1, sqlite3.DIRECTONLY, writefile)
+	}
 	sqlite3.CreateModule(db, "fsdir", nil, func(db *sqlite3.Conn, module, schema, table string, arg ...string) (fsdir, error) {
 		err := db.DeclareVtab(`CREATE TABLE x(name,mode,mtime,data,path HIDDEN,dir HIDDEN)`)
 		db.VtabConfig(sqlite3.VTAB_DIRECTONLY)
-		return fsdir{}, err
+		return fsdir{fs}, err
 	})
 }
 
@@ -24,14 +38,22 @@ func lsmode(ctx sqlite3.Context, arg ...sqlite3.Value) {
 	ctx.ResultText(fs.FileMode(arg[0].Int()).String())
 }
 
-func readfile(ctx sqlite3.Context, arg ...sqlite3.Value) {
-	d, err := os.ReadFile(arg[0].Text())
-	if errors.Is(err, fs.ErrNotExist) {
-		return
-	}
-	if err != nil {
-		ctx.ResultError(fmt.Errorf("readfile: %w", err))
-	} else {
-		ctx.ResultBlob(d)
+func readfile(f fs.FS) func(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	return func(ctx sqlite3.Context, arg ...sqlite3.Value) {
+		var err error
+		var data []byte
+
+		if f != nil {
+			data, err = fs.ReadFile(f, arg[0].Text())
+		} else {
+			data, err = os.ReadFile(arg[0].Text())
+		}
+
+		switch {
+		case err == nil:
+			ctx.ResultBlob(data)
+		case !errors.Is(err, fs.ErrNotExist):
+			ctx.ResultError(fmt.Errorf("readfile: %w", err))
+		}
 	}
 }
diff --git a/ext/fileio/fsdir.go b/ext/fileio/fsdir.go
index e4e331b..d8798fc 100644
--- a/ext/fileio/fsdir.go
+++ b/ext/fileio/fsdir.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"io/fs"
 	"os"
+	"path"
 	"path/filepath"
 	"strings"
 
@@ -13,10 +14,10 @@ import (
 type fsdir struct{ fs.FS }
 
 func (d fsdir) BestIndex(idx *sqlite3.IndexInfo) error {
-	var path, dir bool
+	var root, base bool
 	for i, cst := range idx.Constraint {
 		switch cst.Column {
-		case 4: // path
+		case 4: // root
 			if !cst.Usable || cst.Op != sqlite3.INDEX_CONSTRAINT_EQ {
 				return sqlite3.CONSTRAINT
 			}
@@ -24,8 +25,8 @@ func (d fsdir) BestIndex(idx *sqlite3.IndexInfo) error {
 				Omit:      true,
 				ArgvIndex: 1,
 			}
-			path = true
-		case 5: // dir
+			root = true
+		case 5: // base
 			if !cst.Usable || cst.Op != sqlite3.INDEX_CONSTRAINT_EQ {
 				return sqlite3.CONSTRAINT
 			}
@@ -33,13 +34,13 @@ func (d fsdir) BestIndex(idx *sqlite3.IndexInfo) error {
 				Omit:      true,
 				ArgvIndex: 2,
 			}
-			dir = true
+			base = true
 		}
 	}
-	if path {
+	if root {
 		idx.EstimatedCost = 100
 	}
-	if dir {
+	if base {
 		idx.EstimatedCost = 10
 	}
 	return nil
@@ -51,7 +52,7 @@ func (d fsdir) Open() (sqlite3.VTabCursor, error) {
 
 type cursor struct {
 	fs    fs.FS
-	dir   string
+	base  string
 	rowID int64
 	eof   bool
 	curr  entry
@@ -60,9 +61,9 @@ type cursor struct {
 }
 
 type entry struct {
-	path  string
-	entry fs.DirEntry
-	err   error
+	path string
+	fs.DirEntry
+	err error
 }
 
 func (c *cursor) Close() error {
@@ -84,21 +85,24 @@ func (c *cursor) Filter(idxNum int, idxStr string, arg ...sqlite3.Value) error {
 		return fmt.Errorf("fsdir: wrong number of arguments")
 	}
 
-	path := arg[0].Text()
+	root := arg[0].Text()
 	if len(arg) > 1 {
-		if dir := arg[1].RawText(); c.fs != nil {
-			c.dir = string(dir) + "/"
+		base := arg[1].Text()
+		if c.fs != nil {
+			root = path.Join(base, root)
+			base = path.Clean(base) + "/"
 		} else {
-			c.dir = string(dir) + string(filepath.Separator)
+			root = filepath.Join(base, root)
+			base = filepath.Clean(base) + string(filepath.Separator)
 		}
-		path = c.dir + path
+		c.base = base
 	}
 
 	c.rowID = 0
 	c.eof = false
 	c.next = make(chan entry)
 	c.done = make(chan struct{})
-	go c.WalkDir(path)
+	go c.WalkDir(root)
 	return c.Next()
 }
 
@@ -121,32 +125,32 @@ func (c *cursor) RowID() (int64, error) {
 func (c *cursor) Column(ctx *sqlite3.Context, n int) error {
 	switch n {
 	case 0: // name
-		name := strings.TrimPrefix(c.curr.path, c.dir)
+		name := strings.TrimPrefix(c.curr.path, c.base)
 		ctx.ResultText(name)
 
 	case 1: // mode
-		i, err := c.curr.entry.Info()
+		i, err := c.curr.Info()
 		if err != nil {
 			return err
 		}
 		ctx.ResultInt64(int64(i.Mode()))
 
 	case 2: // mtime
-		i, err := c.curr.entry.Info()
+		i, err := c.curr.Info()
 		if err != nil {
 			return err
 		}
 		ctx.ResultTime(i.ModTime(), sqlite3.TimeFormatUnixFrac)
 
 	case 3: // data
-		switch typ := c.curr.entry.Type(); {
+		switch typ := c.curr.Type(); {
 		case typ.IsRegular():
 			var data []byte
 			var err error
-			if name := c.curr.entry.Name(); c.fs != nil {
-				data, err = fs.ReadFile(c.fs, name)
+			if c.fs != nil {
+				data, err = fs.ReadFile(c.fs, c.curr.path)
 			} else {
-				data, err = os.ReadFile(name)
+				data, err = os.ReadFile(c.curr.path)
 			}
 			if err != nil {
 				return err
@@ -154,7 +158,7 @@ func (c *cursor) Column(ctx *sqlite3.Context, n int) error {
 			ctx.ResultBlob(data)
 
 		case typ&fs.ModeSymlink != 0 && c.fs == nil:
-			t, err := os.Readlink(c.curr.entry.Name())
+			t, err := os.Readlink(c.curr.path)
 			if err != nil {
 				return err
 			}
@@ -188,11 +192,11 @@ func (c *cursor) WalkDir(path string) {
 	}
 }
 
-func (c *cursor) WalkDirFunc(path string, de fs.DirEntry, err error) error {
+func (c *cursor) WalkDirFunc(path string, d fs.DirEntry, err error) error {
 	select {
 	case <-c.done:
 		return fs.SkipAll
-	case c.next <- entry{path, de, err}:
+	case c.next <- entry{path, d, err}:
 		return nil
 	}
 }
diff --git a/vfs/memdb/README.md b/vfs/memdb/README.md
index 07ed91c..193e29d 100644
--- a/vfs/memdb/README.md
+++ b/vfs/memdb/README.md
@@ -1,6 +1,6 @@
 # Go `"memdb"` SQLite VFS
 
-This package implements the [`"memdb"`](https://sqlite.org/src/file/src/memdb.c)
+This package implements the [`"memdb"`](https://sqlite.org/src/doc/tip/src/memdb.c)
 SQLite VFS in pure Go.
 
 It has some benefits over the C version: