crimson/os/seastore/rbm: add do_with() to prevent accessing unavailable reference

Signed-off-by: Myoungwon Oh <[email protected]>

Author: myoungwon

src/crimson/os/seastore/random_block_manager/nvme_block_device.h

@@ -261,34 +261,43 @@ class NVMeBlockDevice : public RBMDevice {
 	device_path,
 	seastar::open_flags::rw | seastar::open_flags::dsync
       ).then([this, stat](auto file) mutable {
-	return file.size().then([this, stat, file](auto size) mutable {
-	  stat.size = size;
-	  return identify_namespace(file
-	  ).safe_then([stat] (auto id_namespace_data) mutable {
-	    // LBA format provides LBA size which is power of 2. LBA is the
-	    // minimum size of read and write.
-	    stat.block_size = (1 << id_namespace_data.lbaf[0].lbads);
-	    if (stat.block_size < RBM_SUPERBLOCK_SIZE) {
-	      stat.block_size = RBM_SUPERBLOCK_SIZE;
-	    } 
+	return seastar::do_with(
+	  file,
+	  [this, stat](auto &file) mutable 
+	{
+	  return file.size().then([this, stat, &file](auto size) mutable {
+	    stat.size = size;
 	    return stat_device_ret(
 	      read_ertr::ready_future_marker{},
 	      stat
 	    );
-	  }).handle_error(crimson::ct_error::input_output_error::handle(
-	    [stat]{
-	    return stat_device_ret(
-	      read_ertr::ready_future_marker{},
-	      stat
-	    );
-	  }), crimson::ct_error::pass_further_all{});
-	}).safe_then([file](auto st) mutable {
-	  return file.close(
-	  ).then([st] {
-	    return stat_device_ret(
-	      read_ertr::ready_future_marker{},
-	      st
-	    );
+	    return identify_namespace(file
+	    ).safe_then([stat] (auto id_namespace_data) mutable {
+	      // LBA format provides LBA size which is power of 2. LBA is the
+	      // minimum size of read and write.
+	      stat.block_size = (1 << id_namespace_data.lbaf[0].lbads);
+	      if (stat.block_size < RBM_SUPERBLOCK_SIZE) {
+		stat.block_size = RBM_SUPERBLOCK_SIZE;
+	      } 
+	      return stat_device_ret(
+		read_ertr::ready_future_marker{},
+		stat
+	      );
+	    }).handle_error(crimson::ct_error::input_output_error::handle(
+	      [stat]{
+	      return stat_device_ret(
+		read_ertr::ready_future_marker{},
+		stat
+	      );
+	    }), crimson::ct_error::pass_further_all{});
+	  }).safe_then([&file](auto st) mutable {
+	    return file.close(
+	    ).then([st] {
+	      return stat_device_ret(
+		read_ertr::ready_future_marker{},
+		st
+	      );
+	    });
 	  });
 	});
       });