FS: Don't default to having a full InodeMetadata in every Inode.

This allows Ext2FS to keep its own ext2_inode around instead.

VirtualFileSystem/Ext2FileSystem.cpp

@@ -221,41 +221,33 @@ Ext2FSInode::~Ext2FSInode()
 {
 }
 
-void Ext2FSInode::populate_metadata() const
-{
-    m_metadata.inode = identifier();
-    m_metadata.size = m_raw_inode.i_size;
-    m_metadata.mode = m_raw_inode.i_mode;
-    m_metadata.uid = m_raw_inode.i_uid;
-    m_metadata.gid = m_raw_inode.i_gid;
-    m_metadata.linkCount = m_raw_inode.i_links_count;
-    m_metadata.atime = m_raw_inode.i_atime;
-    m_metadata.ctime = m_raw_inode.i_ctime;
-    m_metadata.mtime = m_raw_inode.i_mtime;
-    m_metadata.dtime = m_raw_inode.i_dtime;
-    m_metadata.blockSize = fs().blockSize();
-    m_metadata.blockCount = m_raw_inode.i_blocks;
+InodeMetadata Ext2FSInode::metadata() const
+{
+    InodeMetadata metadata;
+    metadata.inode = identifier();
+    metadata.size = m_raw_inode.i_size;
+    metadata.mode = m_raw_inode.i_mode;
+    metadata.uid = m_raw_inode.i_uid;
+    metadata.gid = m_raw_inode.i_gid;
+    metadata.linkCount = m_raw_inode.i_links_count;
+    metadata.atime = m_raw_inode.i_atime;
+    metadata.ctime = m_raw_inode.i_ctime;
+    metadata.mtime = m_raw_inode.i_mtime;
+    metadata.dtime = m_raw_inode.i_dtime;
+    metadata.blockSize = fs().blockSize();
+    metadata.blockCount = m_raw_inode.i_blocks;
 
     if (isBlockDevice(m_raw_inode.i_mode) || isCharacterDevice(m_raw_inode.i_mode)) {
         unsigned dev = m_raw_inode.i_block[0];
-        m_metadata.majorDevice = (dev & 0xfff00) >> 8;
-        m_metadata.minorDevice= (dev & 0xff) | ((dev >> 12) & 0xfff00);
+        metadata.majorDevice = (dev & 0xfff00) >> 8;
+        metadata.minorDevice= (dev & 0xff) | ((dev >> 12) & 0xfff00);
     }
+    return metadata;
 }
 
 void Ext2FSInode::flush_metadata()
 {
     dbgprintf("Ext2FSInode: flush_metadata for inode %u\n", index());
-    m_raw_inode.i_size = m_metadata.size;
-    m_raw_inode.i_mode = m_metadata.mode;
-    m_raw_inode.i_uid = m_metadata.uid;
-    m_raw_inode.i_gid = m_metadata.gid;
-    m_raw_inode.i_links_count = m_metadata.linkCount;
-    m_raw_inode.i_atime = m_metadata.atime;
-    m_raw_inode.i_ctime = m_metadata.ctime;
-    m_raw_inode.i_mtime = m_metadata.mtime;
-    m_raw_inode.i_dtime = m_metadata.dtime;
-    m_raw_inode.i_blocks = m_metadata.blockCount;
     fs().write_ext2_inode(index(), m_raw_inode);
     set_metadata_dirty(false);
 }
@@ -358,7 +350,7 @@ ssize_t Ext2FSInode::read_bytes(Unix::off_t offset, size_t count, byte* buffer,
 bool Ext2FSInode::write(const ByteBuffer& data)
 {
     // FIXME: Support writing to symlink inodes.
-    ASSERT(!m_metadata.isSymbolicLink());
+    ASSERT(!is_symlink());
 
     unsigned blocksNeededBefore = ceilDiv(size(), fs().blockSize());
     unsigned blocksNeededAfter = ceilDiv((unsigned)data.size(), fs().blockSize());
@@ -595,7 +587,6 @@ bool Ext2FS::write_ext2_inode(unsigned inode, const ext2_inode& e2inode)
             auto& cached_inode = *(*it).value;
             LOCKER(cached_inode.m_lock);
             cached_inode.m_raw_inode = e2inode;
-            cached_inode.populate_metadata();
             if (cached_inode.is_directory())
                 cached_inode.m_lookup_cache.clear();
         }
@@ -924,6 +915,7 @@ InodeIdentifier Ext2FS::find_parent_of_inode(InodeIdentifier inode_id) const
     Vector<RetainPtr<Ext2FSInode>> directories_in_group;
 
     for (unsigned i = 0; i < inodes_per_group(); ++i) {
+        // FIXME: Consult the inode bitmap to see which inodes to look into.
         auto group_member = get_inode({ id(), firstInodeInGroup + i });
         if (!group_member)
             continue;
@@ -990,3 +982,48 @@ void Ext2FSInode::one_retain_left()
 {
     // FIXME: I would like to not live forever, but uncached Ext2FS is fucking painful right now.
 }
+
+int Ext2FSInode::set_atime(Unix::time_t t)
+{
+    if (fs().is_readonly())
+        return -EROFS;
+    m_raw_inode.i_atime = t;
+    set_metadata_dirty(true);
+    return 0;
+}
+
+int Ext2FSInode::set_ctime(Unix::time_t t)
+{
+    if (fs().is_readonly())
+        return -EROFS;
+    m_raw_inode.i_ctime = t;
+    set_metadata_dirty(true);
+    return 0;
+}
+
+int Ext2FSInode::set_mtime(Unix::time_t t)
+{
+    if (fs().is_readonly())
+        return -EROFS;
+    m_raw_inode.i_mtime = t;
+    set_metadata_dirty(true);
+    return 0;
+}
+
+int Ext2FSInode::increment_link_count()
+{
+    if (fs().is_readonly())
+        return -EROFS;
+    ++m_raw_inode.i_links_count;
+    set_metadata_dirty(true);
+    return 0;
+}
+
+int Ext2FSInode::decrement_link_count()
+{
+    if (fs().is_readonly())
+        return -EROFS;
+    --m_raw_inode.i_links_count;
+    set_metadata_dirty(true);
+    return 0;
+}

VirtualFileSystem/Ext2FileSystem.h

@@ -27,13 +27,18 @@ public:
 private:
     // ^Inode
     virtual ssize_t read_bytes(Unix::off_t, size_t, byte* buffer, FileDescriptor*) override;
-    virtual void populate_metadata() const override;
+    virtual InodeMetadata metadata() const override;
     virtual bool traverse_as_directory(Function<bool(const FS::DirectoryEntry&)>) override;
     virtual InodeIdentifier lookup(const String& name) override;
     virtual String reverse_lookup(InodeIdentifier) override;
     virtual void flush_metadata() override;
     virtual bool write(const ByteBuffer&) override;
     virtual bool add_child(InodeIdentifier child_id, const String& name, byte file_type, int& error) override;
+    virtual int set_atime(Unix::time_t) override;
+    virtual int set_ctime(Unix::time_t) override;
+    virtual int set_mtime(Unix::time_t) override;
+    virtual int increment_link_count() override;
+    virtual int decrement_link_count() override;
 
     void populate_lookup_cache();
 

VirtualFileSystem/FileSystem.cpp

@@ -111,56 +111,29 @@ void Inode::will_be_destroyed()
         flush_metadata();
 }
 
-int Inode::set_atime(Unix::time_t ts)
+int Inode::set_atime(Unix::time_t)
 {
-    if (fs().is_readonly())
-        return -EROFS;
-    if (m_metadata.atime == ts)
-        return 0;
-    m_metadata.atime = ts;
-    m_metadata_dirty = true;
-    return 0;
+    return -ENOTIMPL;
 }
 
-int Inode::set_ctime(Unix::time_t ts)
+int Inode::set_ctime(Unix::time_t)
 {
-    if (fs().is_readonly())
-        return -EROFS;
-    if (m_metadata.ctime == ts)
-        return 0;
-    m_metadata.ctime = ts;
-    m_metadata_dirty = true;
-    return 0;
+    return -ENOTIMPL;
 }
 
-int Inode::set_mtime(Unix::time_t ts)
+int Inode::set_mtime(Unix::time_t)
 {
-    if (fs().is_readonly())
-        return -EROFS;
-    if (m_metadata.mtime == ts)
-        return 0;
-    m_metadata.mtime = ts;
-    m_metadata_dirty = true;
-    return 0;
+    return -ENOTIMPL;
 }
 
 int Inode::increment_link_count()
 {
-    if (fs().is_readonly())
-        return -EROFS;
-    ++m_metadata.linkCount;
-    m_metadata_dirty = true;
-    return 0;
+    return -ENOTIMPL;
 }
 
 int Inode::decrement_link_count()
 {
-    if (fs().is_readonly())
-        return -EROFS;
-    ASSERT(m_metadata.linkCount);
-    --m_metadata.linkCount;
-    m_metadata_dirty = true;
-    return 0;
+    return -ENOTIMPL;
 }
 
 void FS::sync()

VirtualFileSystem/FileSystem.h

@@ -75,7 +75,7 @@ public:
     bool is_directory() const { return metadata().isDirectory(); }
 
     InodeIdentifier identifier() const { return { fsid(), index() }; }
-    const InodeMetadata& metadata() const { if (!m_metadata.isValid()) { populate_metadata(); } return m_metadata; }
+    virtual InodeMetadata metadata() const = 0;
 
     ByteBuffer read_entire(FileDescriptor* = nullptr);
 
@@ -88,11 +88,11 @@ public:
 
     bool is_metadata_dirty() const { return m_metadata_dirty; }
 
-    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 int set_atime(Unix::time_t);
+    virtual int set_ctime(Unix::time_t);
+    virtual int set_mtime(Unix::time_t);
+    virtual int increment_link_count();
+    virtual int decrement_link_count();
 
     virtual void flush_metadata() = 0;
 
@@ -101,10 +101,7 @@ public:
 protected:
     Inode(FS& fs, unsigned index);
 
-    virtual void populate_metadata() const = 0;
     void set_metadata_dirty(bool b) { m_metadata_dirty = b; }
-
-    mutable InodeMetadata m_metadata;
 private:
     FS& m_fs;
     unsigned m_index { 0 };

VirtualFileSystem/SyntheticFileSystem.cpp

@@ -184,9 +184,9 @@ SynthFSInode::~SynthFSInode()
 {
 }
 
-void SynthFSInode::populate_metadata() const
+InodeMetadata SynthFSInode::metadata() const
 {
-    // Already done when SynthFS created the file.
+    return m_metadata;
 }
 
 ssize_t SynthFSInode::read_bytes(Unix::off_t offset, size_t count, byte* buffer, FileDescriptor* descriptor)

VirtualFileSystem/SyntheticFileSystem.h

@@ -47,7 +47,7 @@ public:
 private:
     // ^Inode
     virtual ssize_t read_bytes(Unix::off_t, size_t, byte* buffer, FileDescriptor*) override;
-    virtual void populate_metadata() const override;
+    virtual InodeMetadata metadata() const override;
     virtual bool traverse_as_directory(Function<bool(const FS::DirectoryEntry&)>) override;
     virtual InodeIdentifier lookup(const String& name) override;
     virtual String reverse_lookup(InodeIdentifier) override;
@@ -64,4 +64,5 @@ private:
     ByteBuffer m_data;
     Function<ByteBuffer()> m_generator;
     Vector<SynthFSInode*> m_children;
+    InodeMetadata m_metadata;
 };

VirtualFileSystem/VirtualFileSystem.cpp

@@ -51,7 +51,7 @@ auto VFS::makeNode(InodeIdentifier inode) -> RetainPtr<Vnode>
     if (!core_inode)
         return nullptr;
 
-    auto& metadata = core_inode->metadata();
+    auto metadata = core_inode->metadata();
 
     InterruptDisabler disabler;
 
@@ -74,7 +74,6 @@ auto VFS::makeNode(InodeIdentifier inode) -> RetainPtr<Vnode>
 
     vnode->inode = inode;
     vnode->m_core_inode = move(core_inode);
-    vnode->m_cachedMetadata = metadata;
 
 #ifdef VFS_DEBUG
     kprintf("makeNode: inode=%u, size=%u, mode=%o, uid=%u, gid=%u\n", inode.index(), metadata.size, metadata.mode, metadata.uid, metadata.gid);
@@ -474,11 +473,12 @@ void Vnode::release()
     }
 }
 
-const InodeMetadata& Vnode::metadata() const
+InodeMetadata Vnode::metadata() const
 {
     if (m_core_inode)
         return m_core_inode->metadata();
-    return m_cachedMetadata;
+    ASSERT_NOT_REACHED();
+    return { };
 }
 
 VFS::Mount::Mount(InodeIdentifier host, RetainPtr<FS>&& guest_fs)

VirtualFileSystem/VirtualFileSystem.h

@@ -38,7 +38,7 @@ class VFS;
 class Vnode {
 public:
     InodeIdentifier inode;
-    const InodeMetadata& metadata() const;
+    InodeMetadata metadata() const;
 
     bool inUse() const { return inode.is_valid() || m_characterDevice; }