feat(ext4): directory entry find/add/remove operations

crates/servers/storage-server/src/fs/ext4/mod.rs

@@ -2,6 +2,7 @@ pub mod io;
 pub mod superblock;
 pub mod bgd;
 pub mod bitmap;
+pub mod dir;
 
 use port_block_device::BlockDevice;
 use crate::filesystem::{DirEntry, FileHandle, FileName, FileSystem};
@@ -194,6 +195,24 @@ impl<B: BlockDevice> Ext4<B> {
         bitmap::free_inode(&mut self.device, &mut self.sb, self.gdt_block, inode, spb);
     }
 
+    pub fn find_in_dir_pub(&mut self, dir_inode_num: u32, name: &[u8]) -> Option<u32> {
+        let inode = self.read_inode(dir_inode_num)?;
+        dir::find_entry(&mut self.device, &self.sb, self.gdt_block, &inode, name)
+    }
+
+    pub fn add_dir_entry(&mut self, dir_inode_num: u32, name: &[u8], child_inode: u32, file_type: u8) -> bool {
+        let inode = match self.read_inode(dir_inode_num) {
+            Some(i) => i,
+            None => return false,
+        };
+        dir::add_entry(&mut self.device, &self.sb, self.gdt_block, &inode, name, child_inode, file_type)
+    }
+
+    pub fn remove_dir_entry(&mut self, dir_inode_num: u32, name: &[u8]) -> Option<u32> {
+        let inode = self.read_inode(dir_inode_num)?;
+        dir::remove_entry(&mut self.device, &self.sb, self.gdt_block, &inode, name)
+    }
+
     fn read_extents(&self, inode: &Inode) -> Option<Extent> {
         if !inode.uses_extents() { return None; }
         let hdr = &inode.block_data;