Refactor range_lock in fs

src/libos/src/fs/file_ops/fcntl.rs

@@ -1,4 +1,4 @@
-use super::flock::c_flock;
+use super::locks::range_lock::c_flock;
 use super::*;
 use util::mem_util::from_user;
 

src/libos/src/fs/locks/mod.rs

@@ -0,0 +1,3 @@
+use super::*;
+
+pub mod range_lock;

src/libos/src/fs/mod.rs

@@ -23,7 +23,7 @@ pub use self::file_ops::{
     IfConf, IoctlCmd, Stat, StatusFlags, StructuredIoctlArgType, StructuredIoctlNum,
 };
 pub use self::file_table::{FileDesc, FileTable, FileTableEvent, FileTableNotifier};
-pub use self::flock::{
+pub use self::locks::range_lock::{
     FileRange, RangeLock, RangeLockBuilder, RangeLockList, RangeLockType, OFFSET_MAX,
 };
 pub use self::fs_ops::Statfs;
@@ -43,7 +43,7 @@ mod events;
 mod file;
 mod file_ops;
 mod file_table;
-mod flock;
+mod locks;
 mod fs_ops;
 mod fs_view;
 mod host_fd;