VFS: vnode cache

src/arch/x86/kmain.cpp

@@ -56,11 +56,13 @@ void ktask_main() {
     (new Task(Task::TaskMode::TASKMODE_KERN, templates_tester, "templates_tester2"))->start();
     // (new Task(Task::TaskMode::TASKMODE_KERN, vfs_tester, "vfs_tester"))->start();
 
+    VFSGlobals::root = SharedPtr<RootNode>(new RootNode());
+
     for (int i = 0; i < saved_modules_size; i++) {
         auto &mod = saved_modules[i];
 
         if (strcmp(saved_modules_names[i], "/sysroot.tar") == 0) {
-            VFSGlobals::mounts.add_mount(new TarFs((char *) mod.address, mod.size, &VFSGlobals::root));
+            VFSGlobals::mounts.add_mount(new TarFs((char *) mod.address, mod.size))->set_root(static_ptr_cast<NodeDir>(VFSGlobals::root));
         }
     }
     GlobalTtyManager.all_tty_putstr("Setup finished \n");

src/kernel/vfs/FDT.cpp

@@ -14,7 +14,7 @@
 #include <sys/fcntl.h>
 
 FDT::FD FDT::open(const Path &p, int opts) {
-    if (auto n = VFSGlobals::root.traverse(p); n.get() != nullptr) {
+    if (auto n = VFSGlobals::root->traverse(p); n.get() != nullptr) {
         LockGuard l(_mtx);
         _files.emplace(_cur_fd++, UniquePtr<File>(new File(n, opts)));
         return _cur_fd - 1;

src/kernel/vfs/Filesystem.cpp

@@ -4,8 +4,33 @@
 
 #include "Filesystem.hpp"
 
-Filesystem::~Filesystem() = default;
-Filesystem::Filesystem(NodeDir *mounted_on) : _mounted_on(mounted_on) {
+Filesystem::~Filesystem() {
+    if (_mounted_on.get()) {
+        _mounted_on->set_mounted(nullptr);
+    }
+}
+
+void Filesystem::set_root(SharedPtr<NodeDir> node) {
+    _mounted_on = std::move(node);
     assert(_mounted_on->type() == Node::DIR);
     _mounted_on->set_mounted(this);
 }
+
+SharedPtr<Node> Filesystem::get_node(ino_t inode) {
+    {
+        LockGuard l(_vnode_cache_lock);
+        if (auto p = _vnode_cache.find(inode); p != _vnode_cache.end())
+            if (auto l = p->second.lock()) return *l;
+    }
+
+    auto found = get_node_impl(inode);
+
+    {
+        LockGuard l(_vnode_cache_lock);
+        if (auto p = _vnode_cache.find(inode); p != _vnode_cache.end())
+            if (auto l = p->second.lock()) return *l;
+
+        _vnode_cache.emplace(inode, found);
+        return found;
+    }
+}

src/kernel/vfs/Filesystem.hpp

@@ -8,16 +8,29 @@
 #include "Node.hpp"
 
 #include "PointersCollection.hpp"
+#include "SkipList.hpp"
 
 class Filesystem {
 public:
-    Filesystem(NodeDir *mounted_on);
+    Filesystem()          = default;
     virtual ~Filesystem() = 0;
 
-    virtual SharedPtr<NodeDir> root()                = 0;
-    virtual SharedPtr<Node>    get_node(ino_t inode) = 0;
+    Filesystem(Filesystem const &other)            = delete;
+    Filesystem &operator=(Filesystem const &other) = delete;
 
-    NodeDir *_mounted_on;
+    virtual SharedPtr<NodeDir> root() = 0;
+    virtual SharedPtr<Node>    get_node(ino_t inode);
+
+    void set_root(SharedPtr<NodeDir> node_dir);
+
+protected:
+    virtual SharedPtr<Node> get_node_impl(ino_t inode) = 0;
+
+    SharedPtr<NodeDir> _mounted_on;
+
+private:
+    SkipListMap<ino_t, WeakPtr<Node>> _vnode_cache;
+    Mutex                             _vnode_cache_lock;
 };
 
 

src/kernel/vfs/MemFs.cpp

@@ -84,7 +84,7 @@ size_t MemFs::MemFsNodeFile::size() {
     LockGuard l2(_fs_node->lock);
     return _fs_node->data.size();
 }
-MemFs::MemFs(NodeDir *mounted_on) : Filesystem(mounted_on) {
+MemFs::MemFs() {
     _files.emplace(1, new DirInode{1});
     _top_inode = 2;
 }
@@ -100,7 +100,7 @@ SharedPtr<NodeDir> MemFs::root() {
         return static_ptr_cast<NodeDir>(MemFsNodeDir::create(this, static_ptr_cast<DirInode>(root)));
     }
 }
-SharedPtr<Node> MemFs::get_node(ino_t inode) {
+SharedPtr<Node> MemFs::get_node_impl(ino_t inode) {
     LockGuard l(_files_lock);
     auto      found = _files.find(inode);
     if (found == _files.end()) return nullptr;

src/kernel/vfs/MemFs.hpp

@@ -91,10 +91,10 @@ private:
     };
 
 public:
-    MemFs(NodeDir *mounted_on);
+    MemFs();
 
     SharedPtr<NodeDir> root() override;
-    SharedPtr<Node>    get_node(ino_t inode) override;
+    SharedPtr<Node>    get_node_impl(ino_t inode) override;
 
 private:
     ino_t                                _top_inode;

src/kernel/vfs/MountTable.cpp

@@ -3,6 +3,7 @@
 //
 
 #include "MountTable.hpp"
-void MountTable::add_mount(Filesystem *fs) {
+Filesystem *MountTable::add_mount(Filesystem *fs) {
     _mounts.emplace_front(fs);
+    return fs;
 }

src/kernel/vfs/MountTable.hpp

@@ -13,7 +13,7 @@
 
 class MountTable {
 public:
-    void add_mount(Filesystem *fs);
+    Filesystem *add_mount(Filesystem *fs);
 
 private:
     List<Filesystem *> _mounts;

src/kernel/vfs/TarFs.cpp

@@ -7,7 +7,7 @@
 #include <TtyManager.hpp>
 
 
-TarFs::TarFs(char *backing, size_t backing_size, NodeDir *mounted_on) : Filesystem(mounted_on), _backing((tar_header *) backing), _backing_size(backing_size) {
+TarFs::TarFs(char *backing, size_t backing_size) : _backing((tar_header *) backing), _backing_size(backing_size) {
     int i = 2;
 
     const tar_header *header = _backing;
@@ -89,7 +89,7 @@ SharedPtr<NodeDir> TarFs::root() {
     return static_ptr_cast<NodeDir>(get_node(1));
 }
 
-SharedPtr<Node> TarFs::get_node(ino_t inode) {
+SharedPtr<Node> TarFs::get_node_impl(ino_t inode) {
     if (_dir_map.find(inode) != _dir_map.end()) {
         return static_ptr_cast<Node>(TarFsNodeDir::create(this, inode));
     } else {

src/kernel/vfs/TarFs.hpp

@@ -9,11 +9,11 @@
 
 class TarFs : public Filesystem {
 public:
-    TarFs(char *backing, size_t backing_size, NodeDir *mounted_on);
+    TarFs(char *backing, size_t backing_size);
     ~TarFs() override = default;
 
     SharedPtr<NodeDir> root() override;
-    SharedPtr<Node>    get_node(ino_t inode) override;
+    SharedPtr<Node>    get_node_impl(ino_t inode) override;
 
 
     struct TarFsNodeDir : public ::NodeDir {

src/kernel/vfs/VFSGlobals.cpp

@@ -17,5 +17,5 @@ ino_t RootNode::mkfile(const String &name) {
 }
 
 
-RootNode   VFSGlobals::root;
-MountTable VFSGlobals::mounts;
+SharedPtr<RootNode> VFSGlobals::root;
+MountTable          VFSGlobals::mounts;

src/kernel/vfs/VFSGlobals.hpp

@@ -19,8 +19,8 @@ public:
 };
 
 namespace VFSGlobals {
-    extern RootNode   root;
-    extern MountTable mounts;
+    extern SharedPtr<RootNode> root;
+    extern MountTable          mounts;
 } // namespace VFSGlobals