From 4238e2e9be9c3e26c634c09db97d531401b6996b Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Sun, 11 Jul 2021 00:50:08 +0200
Subject: [PATCH] Kernel: Only allow looking up Mounts by InodeIdentifier

Let's simplify the interface by not allowing lookup by Inode&.
---
 Kernel/FileSystem/VirtualFileSystem.cpp | 24 +++---------------------
 Kernel/FileSystem/VirtualFileSystem.h   |  2 --
 2 files changed, 3 insertions(+), 23 deletions(-)

diff --git a/Kernel/FileSystem/VirtualFileSystem.cpp b/Kernel/FileSystem/VirtualFileSystem.cpp
index 1066de52e4..a82398090b 100644
--- a/Kernel/FileSystem/VirtualFileSystem.cpp
+++ b/Kernel/FileSystem/VirtualFileSystem.cpp
@@ -82,7 +82,7 @@ KResult VirtualFileSystem::remount(Custody& mount_point, int new_flags)
 
     dbgln("VirtualFileSystem: Remounting {}", mount_point.try_create_absolute_path());
 
-    Mount* mount = find_mount_for_guest(mount_point.inode());
+    Mount* mount = find_mount_for_guest(mount_point.inode().identifier());
     if (!mount)
         return ENODEV;
 
@@ -139,15 +139,6 @@ bool VirtualFileSystem::mount_root(FileSystem& fs)
     return true;
 }
 
-auto VirtualFileSystem::find_mount_for_host(Inode& inode) -> Mount*
-{
-    for (auto& mount : m_mounts) {
-        if (mount.host() == &inode)
-            return &mount;
-    }
-    return nullptr;
-}
-
 auto VirtualFileSystem::find_mount_for_host(InodeIdentifier id) -> Mount*
 {
     for (auto& mount : m_mounts) {
@@ -157,15 +148,6 @@ auto VirtualFileSystem::find_mount_for_host(InodeIdentifier id) -> Mount*
     return nullptr;
 }
 
-auto VirtualFileSystem::find_mount_for_guest(Inode& inode) -> Mount*
-{
-    for (auto& mount : m_mounts) {
-        if (&mount.guest() == &inode)
-            return &mount;
-    }
-    return nullptr;
-}
-
 auto VirtualFileSystem::find_mount_for_guest(InodeIdentifier id) -> Mount*
 {
     for (auto& mount : m_mounts) {
@@ -192,7 +174,7 @@ KResult VirtualFileSystem::traverse_directory_inode(Inode& dir_inode, Function<b
         // FIXME: This is now broken considering chroot and bind mounts.
         bool is_root_inode = dir_inode.identifier() == dir_inode.fs().root_inode()->identifier();
         if (is_root_inode && !is_vfs_root(dir_inode.identifier()) && entry.name == "..") {
-            auto mount = find_mount_for_guest(dir_inode);
+            auto mount = find_mount_for_guest(dir_inode.identifier());
             VERIFY(mount);
             VERIFY(mount->host());
             resolved_inode = mount->host()->identifier();
@@ -965,7 +947,7 @@ KResultOr<NonnullRefPtr<Custody>> VirtualFileSystem::resolve_path_without_veil(S
 
         // See if there's something mounted on the child; in that case
         // we would need to return the guest inode, not the host inode.
-        if (auto mount = find_mount_for_host(*child_inode)) {
+        if (auto mount = find_mount_for_host(child_inode->identifier())) {
             child_inode = mount->guest();
             mount_flags_for_child = mount->flags();
         }
diff --git a/Kernel/FileSystem/VirtualFileSystem.h b/Kernel/FileSystem/VirtualFileSystem.h
index 58241db6d2..c0820cc9ea 100644
--- a/Kernel/FileSystem/VirtualFileSystem.h
+++ b/Kernel/FileSystem/VirtualFileSystem.h
@@ -86,9 +86,7 @@ private:
 
     KResult traverse_directory_inode(Inode&, Function<bool(FileSystem::DirectoryEntryView const&)>);
 
-    Mount* find_mount_for_host(Inode&);
     Mount* find_mount_for_host(InodeIdentifier);
-    Mount* find_mount_for_guest(Inode&);
     Mount* find_mount_for_guest(InodeIdentifier);
 
     Lock m_lock { "VFSLock" };