block: raw: Impl Resizable for RawDisk

Use the block device aware resize from RawFileDisk. For block
devices, verify the externally set size matches instead of
calling ftruncate. For regular files, truncate as usual.

Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>

block/src/raw_disk.rs

@@ -3,6 +3,8 @@
 // SPDX-License-Identifier: Apache-2.0 AND BSD-3-Clause
 
 use std::fs::File;
+use std::io;
+use std::os::unix::fs::FileTypeExt;
 use std::os::unix::io::AsRawFd;
 
 use log::warn;
@@ -77,3 +79,32 @@ impl disk_file::SparseCapable for RawDisk {
         probe_sparse_support(&self.file)
     }
 }
+
+impl disk_file::Resizable for RawDisk {
+    fn resize(&mut self, size: u64) -> BlockResult<()> {
+        let fd_metadata = self
+            .file
+            .metadata()
+            .map_err(|e| BlockError::new(BlockErrorKind::Io, DiskFileError::ResizeError(e)))?;
+
+        if fd_metadata.file_type().is_block_device() {
+            // Block devices cannot be resized via ftruncate; they are resized
+            // externally (LVM, losetup, etc.). Verify the size matches.
+            let (actual_size, _) = query_device_size(&self.file)
+                .map_err(|e| BlockError::new(BlockErrorKind::Io, DiskFileError::ResizeError(e)))?;
+            if actual_size != size {
+                return Err(BlockError::new(
+                    BlockErrorKind::Io,
+                    DiskFileError::ResizeError(io::Error::other(format!(
+                        "Block device size {actual_size} does not match requested size {size}"
+                    ))),
+                ));
+            }
+            Ok(())
+        } else {
+            self.file
+                .set_len(size)
+                .map_err(|e| BlockError::new(BlockErrorKind::Io, DiskFileError::ResizeError(e)))
+        }
+    }
+}