Only format /data in recovery if user specified a new fstype

recovery mode does not have key services, so formatting volumes in
recovery would result in an unencrypted image.
If init detects an unencrypted /data image, encrypt_inplace would be
called. We would like to avoid using `encrypt_inplace` in production.
So do not format /data in recovery for regular data wipes.

Test: th
Bug: 293313353
Change-Id: I401da2a876ed22b426872c80c231397c12ec0737
diff --git a/recovery_utils/roots.cpp b/recovery_utils/roots.cpp
index 6396d44..bc8bc40 100644
--- a/recovery_utils/roots.cpp
+++ b/recovery_utils/roots.cpp
@@ -177,10 +177,27 @@
   }
 
   // If the raw disk will be used as a metadata encrypted device mapper target,
-  // next boot will first mount this partition as read only, and then unmount,
-  // call encrypt_inplace.
+  // next boot will do encrypt_in_place the raw disk. While fs_mgr mounts /data
+  // as RO to avoid write file operations before encrypt_inplace, this code path
+  // is not well tested so we would like to avoid it if possible. For safety,
+  // let vold do the formatting on boot for metadata encrypted devices, except
+  // when user specified a new fstype. Because init formats /data according
+  // to fstab, it's difficult to override the fstab in init.
+  if (!v->metadata_key_dir.empty() && length == 0 && new_fstype.empty()) {
+    android::base::unique_fd fd(open(v->blk_device.c_str(), O_RDWR));
+    if (fd == -1) {
+      PLOG(ERROR) << "format_volume: failed to open " << v->blk_device;
+      return -1;
+    }
+    int64_t device_size = get_file_size(fd.get(), 0);
+    if (device_size > 0 && !wipe_block_device(fd.get(), device_size)) {
+      LOG(INFO) << "format_volume: wipe metadata encrypted " << v->blk_device << " with size "
+                << device_size;
+      return 0;
+    }
+  }
 
-  if ((v->fs_type == "ext4" && new_fstype.empty()) || new_fstype == "ext4") {
+  if (new_fstype == "ext4") {
     LOG(INFO) << "Formatting " << v->blk_device << " as ext4";
     static constexpr int kBlockSize = 4096;
     std::vector<std::string> mke2fs_args = {