mount: handle unknown fstype by trying a fixed list of common fstypes

src/mount.rs

@@ -40,6 +40,27 @@ pub fn mount_apivfs(dst: &str, fstype: &str, flags: MsFlags, data: Option<&str>)
     Ok(())
 }
 
+pub fn mount_regular(
+    src: Option<&str>,
+    dst: &str,
+    fstype: Option<&str>,
+    flags: MsFlags,
+    data: Option<&str>,
+) -> Result<()> {
+    if fstype.is_some() {
+        do_mount(src, dst, fstype, flags, data)
+    } else {
+        let mut result = Ok(());
+        for fstype in ["ext4", "erofs", "squashfs", "f2fs", "btrfs"] {
+            result = do_mount(src, dst, Some(fstype), flags, data);
+            if result.is_ok() {
+                return Ok(());
+            }
+        }
+        result
+    }
+}
+
 pub fn mount_root(
     device: Option<&str>,
     fstype: Option<&str>,
@@ -61,7 +82,7 @@ pub fn mount_root(
         fsflags.bits(),
         flags.unwrap_or_default()
     );
-    do_mount(device, "/root", fstype, fsflags, flags)?;
+    mount_regular(device, "/root", fstype, fsflags, flags)?;
 
     Ok(())
 }

test/test_basic.py

@@ -41,7 +41,7 @@ def assert_apivfs(result):
 def test_basic_ext4(genimage, qemu):
     qemu.set_initramfs(genimage.get_initramfs())
     qemu.set_diskimage(genimage.get_ext4_disk())
-    qemu.set_cmdline("rootwait root=/dev/vda1 rootfstype=ext4")
+    qemu.set_cmdline("rootwait root=/dev/vda1")
     result = qemu.run()
     result.assert_system_state()
     root_mount = result.get_mount(mount_point="/")
@@ -90,7 +90,7 @@ def test_nfs_bind_mounts(rsinit, genimage, qemu):
 
 def test_missing_root(genimage, qemu):
     qemu.set_initramfs(genimage.get_initramfs())
-    qemu.set_cmdline("root=/dev/vda1 rootfstype=ext4")
+    qemu.set_cmdline("root=/dev/vda1")
     result = qemu.run()
     assert result.rsinit_messages == [
         {"message": "Timeout reached while waiting for the device"}
@@ -103,7 +103,7 @@ def test_verity(rsinit, genimage, qemu):
     qemu.set_diskimage(disk)
     files = {"/init": rsinit.rdinit_path, "/verity-params": verity_params}
     qemu.set_initramfs(genimage.create_initramfs_with_files("ext4-verity", files))
-    qemu.set_cmdline("rootwait rsinit.verity_root=/dev/vda1 rootfstype=ext4")
+    qemu.set_cmdline("rootwait rsinit.verity_root=/dev/vda1")
     result = qemu.run()
     result.assert_system_state()
     root_mount = result.get_mount(mount_point="/")