From b0db0e5de0909ad151b9e3e3f40993ef83865443 Mon Sep 17 00:00:00 2001
From: Andreas Kling <awesomekling@gmail.com>
Date: Mon, 24 Dec 2018 23:58:00 +0100
Subject: [PATCH] Get rid of Ext2FS::modify_link_count() in favor of Inode
 accessors.

---
 VirtualFileSystem/Ext2FileSystem.cpp | 30 +++++++++-------------------
 VirtualFileSystem/Ext2FileSystem.h   |  2 --
 VirtualFileSystem/FileSystem.cpp     | 19 ++++++++++++++++++
 VirtualFileSystem/FileSystem.h       |  2 ++
 4 files changed, 30 insertions(+), 23 deletions(-)

diff --git a/VirtualFileSystem/Ext2FileSystem.cpp b/VirtualFileSystem/Ext2FileSystem.cpp
index 0bf5fa52b7b..730ec3f93f4 100644
--- a/VirtualFileSystem/Ext2FileSystem.cpp
+++ b/VirtualFileSystem/Ext2FileSystem.cpp
@@ -612,20 +612,6 @@ void Ext2FS::traverse_block_bitmap(unsigned groupIndex, F callback) const
     }
 }
 
-bool Ext2FS::modify_link_count(InodeIndex inode, int delta)
-{
-    ASSERT(inode);
-    auto e2inode = lookup_ext2_inode(inode);
-    if (!e2inode)
-        return false;
-
-    auto newLinkCount = e2inode->i_links_count + delta;
-    dbgprintf("Ext2FS: changing inode %u link count from %u to %u\n", inode, e2inode->i_links_count, newLinkCount);
-    e2inode->i_links_count = newLinkCount;
-
-    return write_ext2_inode(inode, *e2inode);
-}
-
 bool Ext2FS::write_ext2_inode(unsigned inode, const ext2_inode& e2inode)
 {
     unsigned blockIndex;
@@ -830,9 +816,9 @@ bool Ext2FS::set_block_allocation_state(GroupIndex group, BlockIndex bi, bool ne
     return true;
 }
 
-RetainPtr<Inode> Ext2FS::create_directory(InodeIdentifier parentInode, const String& name, Unix::mode_t mode, int& error)
+RetainPtr<Inode> Ext2FS::create_directory(InodeIdentifier parent_id, const String& name, Unix::mode_t mode, int& error)
 {
-    ASSERT(parentInode.fsid() == id());
+    ASSERT(parent_id.fsid() == id());
 
     // Fix up the mode to definitely be a directory.
     // FIXME: This is a bit on the hackish side.
@@ -841,21 +827,23 @@ RetainPtr<Inode> Ext2FS::create_directory(InodeIdentifier parentInode, const Str
 
     // NOTE: When creating a new directory, make the size 1 block.
     //       There's probably a better strategy here, but this works for now.
-    auto inode = create_inode(parentInode, name, mode, blockSize(), error);
+    auto inode = create_inode(parent_id, name, mode, blockSize(), error);
     if (!inode)
-        return { };
+        return nullptr;
 
     dbgprintf("Ext2FS: create_directory: created new directory named '%s' with inode %u\n", name.characters(), inode->identifier().index());
 
     Vector<DirectoryEntry> entries;
     entries.append({ ".", inode->identifier(), EXT2_FT_DIR });
-    entries.append({ "..", parentInode, EXT2_FT_DIR });
+    entries.append({ "..", parent_id, EXT2_FT_DIR });
 
     bool success = write_directory_inode(inode->identifier().index(), move(entries));
     ASSERT(success);
 
-    success = modify_link_count(parentInode.index(), 1);
-    ASSERT(success);
+    auto parent_inode = get_inode(parent_id);
+    error = parent_inode->increment_link_count();
+    if (error < 0)
+        return nullptr;
 
     auto& bgd = const_cast<ext2_group_desc&>(group_descriptor(group_index_from_inode(inode->identifier().index())));
     ++bgd.bg_used_dirs_count;
diff --git a/VirtualFileSystem/Ext2FileSystem.h b/VirtualFileSystem/Ext2FileSystem.h
index 52c849eebb7..3e4992f53de 100644
--- a/VirtualFileSystem/Ext2FileSystem.h
+++ b/VirtualFileSystem/Ext2FileSystem.h
@@ -94,8 +94,6 @@ private:
     bool set_inode_allocation_state(unsigned inode, bool);
     bool set_block_allocation_state(GroupIndex, BlockIndex, bool);
 
-    bool modify_link_count(InodeIndex, int delta);
-
     unsigned m_blockGroupCount { 0 };
 
     mutable ByteBuffer m_cached_super_block;
diff --git a/VirtualFileSystem/FileSystem.cpp b/VirtualFileSystem/FileSystem.cpp
index 567c9647c2b..b5429d09cd7 100644
--- a/VirtualFileSystem/FileSystem.cpp
+++ b/VirtualFileSystem/FileSystem.cpp
@@ -144,6 +144,25 @@ int Inode::set_mtime(Unix::time_t ts)
     return 0;
 }
 
+int Inode::increment_link_count()
+{
+    if (fs().is_readonly())
+        return -EROFS;
+    ++m_metadata.linkCount;
+    m_metadata_dirty = true;
+    return 0;
+}
+
+int Inode::decrement_link_count()
+{
+    if (fs().is_readonly())
+        return -EROFS;
+    ASSERT(m_metadata.linkCount);
+    --m_metadata.linkCount;
+    m_metadata_dirty = true;
+    return 0;
+}
+
 void FS::sync()
 {
     for (auto* inode : all_inodes()) {
diff --git a/VirtualFileSystem/FileSystem.h b/VirtualFileSystem/FileSystem.h
index cd5958885c5..dc7727e5f39 100644
--- a/VirtualFileSystem/FileSystem.h
+++ b/VirtualFileSystem/FileSystem.h
@@ -88,6 +88,8 @@ public:
     int set_atime(Unix::time_t);
     int set_ctime(Unix::time_t);
     int set_mtime(Unix::time_t);
+    int increment_link_count();
+    int decrement_link_count();
 
     virtual void flush_metadata() = 0;