From 9d55cf1d8024de62da80a497e650d57ecf710b3b Mon Sep 17 00:00:00 2001
From: Bananymous <bananymousosq@gmail.com>
Date: Mon, 25 Sep 2023 20:31:40 +0300
Subject: [PATCH] Kernel: Ext2 inodes are now stored in cache

This allows faster inode access and ensures working inodes when
opened in multiple places.
---
 kernel/include/kernel/FS/Ext2/FileSystem.h |  5 +++++
 kernel/kernel/FS/Ext2/Inode.cpp            | 11 ++++++++---
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/kernel/include/kernel/FS/Ext2/FileSystem.h b/kernel/include/kernel/FS/Ext2/FileSystem.h
index 79a3276bde..1d1622718a 100644
--- a/kernel/include/kernel/FS/Ext2/FileSystem.h
+++ b/kernel/include/kernel/FS/Ext2/FileSystem.h
@@ -1,5 +1,6 @@
 #pragma once
 
+#include <BAN/HashMap.h>
 #include <kernel/Storage/StorageDevice.h>
 #include <kernel/FS/FileSystem.h>
 #include <kernel/FS/Ext2/Inode.h>
@@ -65,6 +66,8 @@ namespace Kernel
 
 		BAN::ErrorOr<uint32_t> reserve_free_block(uint32_t primary_bgd);
 
+		BAN::HashMap<ino_t, BAN::RefPtr<Inode>>& inode_cache() { return m_inode_cache; }
+
 		const Ext2::Superblock& superblock() const { return m_superblock; }
 
 		struct BlockLocation
@@ -104,6 +107,8 @@ namespace Kernel
 		BAN::RefPtr<Inode> m_root_inode;
 		BAN::Vector<uint32_t> m_superblock_backups;
 
+		BAN::HashMap<ino_t, BAN::RefPtr<Inode>> m_inode_cache;
+
 		BlockBufferManager m_buffer_manager;
 
 		Ext2::Superblock m_superblock;
diff --git a/kernel/kernel/FS/Ext2/Inode.cpp b/kernel/kernel/FS/Ext2/Inode.cpp
index 31fdefbc74..ade4789c46 100644
--- a/kernel/kernel/FS/Ext2/Inode.cpp
+++ b/kernel/kernel/FS/Ext2/Inode.cpp
@@ -23,6 +23,9 @@ namespace Kernel
 
 	BAN::ErrorOr<BAN::RefPtr<Inode>> Ext2Inode::create(Ext2FS& fs, uint32_t inode_ino)
 	{
+		if (fs.inode_cache().contains(inode_ino))
+			return fs.inode_cache()[inode_ino];
+
 		auto inode_location = fs.locate_inode(inode_ino);
 
 		auto block_buffer = fs.get_block_buffer();
@@ -30,10 +33,12 @@ namespace Kernel
 
 		auto& inode = *(Ext2::Inode*)(block_buffer.data() + inode_location.offset);
 
-		Ext2Inode* result = new Ext2Inode(fs, inode, inode_ino);
-		if (result == nullptr)
+		Ext2Inode* result_ptr = new Ext2Inode(fs, inode, inode_ino);
+		if (result_ptr == nullptr)
 			return BAN::Error::from_errno(ENOMEM);
-		return BAN::RefPtr<Inode>::adopt(result);
+		auto result = BAN::RefPtr<Inode>::adopt(result_ptr);
+		TRY(fs.inode_cache().insert(inode_ino, result));
+		return result;
 	}
 
 #define VERIFY_AND_READ_BLOCK(expr) do { const uint32_t block_index = expr; ASSERT(block_index); m_fs.read_block(block_index, block_buffer); } while (false)