diff --git a/wit/types.wit b/wit/types.wit
index 0f7d96e..e1f2ec6 100644
--- a/wit/types.wit
+++ b/wit/types.wit
@@ -102,10 +102,6 @@ interface types {
     ///
     /// Note: This was called `filestat` in earlier versions of WASI.
     record descriptor-stat {
-        /// Device ID of device containing the file.
-        device: device,
-        /// File serial number.
-        inode: inode,
         /// File type.
         %type: descriptor-type,
         /// Number of hard links to the file.
@@ -166,14 +162,6 @@ interface types {
     /// Number of hard links to an inode.
     type link-count = u64
 
-    /// Identifier for a device containing a file system. Can be used in
-    /// combination with `inode` to uniquely identify a file or directory in
-    /// the filesystem.
-    type device = u64
-
-    /// Filesystem object serial number that is unique within its file system.
-    type inode = u64
-
     /// When setting a timestamp, this gives the value to set it to.
     variant new-timestamp {
         /// Leave the timestamp set to its previous value.
@@ -187,14 +175,6 @@ interface types {
 
     /// A directory entry.
     record directory-entry {
-        /// The serial number of the object referred to by this directory entry.
-        /// May be none if the inode value is not known.
-        ///
-        /// When this is none, libc implementations might do an extra `stat-at`
-        /// call to retrieve the inode number to fill their `d_ino` fields, so
-        /// implementations which can set this to a non-none value should do so.
-        inode: option<inode>,
-
         /// The type of the file referred to by this directory entry.
         %type: descriptor-type,
 
@@ -485,14 +465,20 @@ interface types {
 
     /// Return the attributes of an open file or directory.
     ///
-    /// Note: This is similar to `fstat` in POSIX.
+    /// Note: This is similar to `fstat` in POSIX, except that it does not return
+    /// device and inode information. For testing whether two descriptors refer to
+    /// the same underlying filesystem object, use `is-same-object`. To obtain
+    /// additional data that can be used do determine whether a file has been
+    /// modified, use `metadata-hash`.
     ///
     /// Note: This was called `fd_filestat_get` in earlier versions of WASI.
     stat: func(this: descriptor) -> result<descriptor-stat, error-code>
 
     /// Return the attributes of a file or directory.
     ///
-    /// Note: This is similar to `fstatat` in POSIX.
+    /// Note: This is similar to `fstatat` in POSIX, except that it does not
+    /// return device and inode information. See the `stat` description for a
+    /// discussion of alternatives.
     ///
     /// Note: This was called `path_filestat_get` in earlier versions of WASI.
     stat-at: func(
@@ -800,4 +786,43 @@ interface types {
     /// Dispose of the specified `directory-entry-stream`, after which it may no longer
     /// be used.
     drop-directory-entry-stream: func(this: directory-entry-stream)
+
+    /// Test whether two descriptors refer to the same filesystem object.
+    ///
+    /// In POSIX, this corresponds to testing whether the two descriptors have the
+    /// same device (`st_dev`) and inode (`st_ino` or `d_ino`) numbers.
+    /// wasi-filesystem does not expose device and inode numbers, so this function
+    /// may be used instead.
+    is-same-object: func(other: descriptor) -> bool
+
+    /// Return a hash of the metadata associated with a filesystem object referred
+    /// to by a descriptor.
+    ///
+    /// This returns a hash of the last-modification timestamp and file size, and
+    /// may also include the inode number, device number, birth timestamp, and
+    /// other metadata fields that may change when the file is modified or
+    /// replaced.
+    ///
+    /// Implementations are encourated to provide the following properties:
+    ///
+    ///  - If the file is not modified or replaced, the computed hash value should
+    ///    usually not change.
+    ///  - If the object is modified or replaced, the computed hash value should
+    ///    usually change.
+    ///  - The inputs to the hash should not be easily computable from the
+    ///    computed hash.
+    ///
+    /// However, none of these is required.
+    metadata-hash: func() -> result<tuple<u64, u64>, error-code>
+
+    /// Return a hash of the metadata associated with a filesystem object referred
+    /// to by a directory descriptor and a relative path.
+    ///
+    /// This performs the same hash computation as `metadata-hash`.
+    metadata-hash-at: func(
+        /// Flags determining the method of how the path is resolved.
+        path-flags: path-flags,
+        /// The relative path of the file or directory to inspect.
+        path: string,
+    ) -> result<tuple<u64, u64>, error-code>
 }