Kernel: Allow Ext2FS::flush_writes() to return ErrorOr<void>

Author: https://github.com/Zak-K-Abdi 🔰
Commit: https://github.com/SerenityOS/serenity/commit/abcf05801a
Pull-request: https://github.com/SerenityOS/serenity/pull/20297
Reviewed-by: https://github.com/AtkinsSJ ✅

Kernel/FileSystem/BlockBasedFileSystem.cpp

@@ -305,9 +305,10 @@ void BlockBasedFileSystem::flush_writes_impl()
     });
 }
 
-void BlockBasedFileSystem::flush_writes()
+ErrorOr<void> BlockBasedFileSystem::flush_writes()
 {
     flush_writes_impl();
+    return {};
 }
 
 }

Kernel/FileSystem/BlockBasedFileSystem.h

@@ -19,7 +19,7 @@ public:
 
     u64 device_block_size() const { return m_device_block_size; }
 
-    virtual void flush_writes() override;
+    virtual ErrorOr<void> flush_writes() override;
     void flush_writes_impl();
 
 protected:

Kernel/FileSystem/Ext2FS/FileSystem.cpp

@@ -662,7 +662,7 @@ void Ext2FS::flush_block_group_descriptor_table()
     }
 }
 
-void Ext2FS::flush_writes()
+ErrorOr<void> Ext2FS::flush_writes()
 {
     {
         MutexLocker locker(m_lock);
@@ -670,8 +670,7 @@ void Ext2FS::flush_writes()
             auto result = flush_super_block();
             if (result.is_error()) {
                 dbgln("Ext2FS[{}]::flush_writes(): Failed to write superblock: {}", fsid(), result.error());
-                // FIXME: We should handle this error.
-                VERIFY_NOT_REACHED();
+                return result.release_error();
             }
             m_super_block_dirty = false;
         }
@@ -708,7 +707,13 @@ void Ext2FS::flush_writes()
         });
     }
 
-    BlockBasedFileSystem::flush_writes();
+    auto result = BlockBasedFileSystem::flush_writes();
+    if (result.is_error()) {
+        dbgln("Ext2FS[{}]::flush_writes(): Failed to flush writes: {}", BlockBasedFileSystem::fsid(), result.error());
+        return result.release_error();
+    }
+
+    return {};
 }
 
 ErrorOr<NonnullRefPtr<Ext2FSInode>> Ext2FS::build_root_inode() const

Kernel/FileSystem/Ext2FS/FileSystem.h

@@ -77,7 +77,7 @@ private:
     ErrorOr<NonnullRefPtr<Inode>> get_inode(InodeIdentifier) const;
     ErrorOr<NonnullRefPtr<Inode>> create_inode(Ext2FSInode& parent_inode, StringView name, mode_t, dev_t, UserID, GroupID);
     ErrorOr<NonnullRefPtr<Inode>> create_directory(Ext2FSInode& parent_inode, StringView name, mode_t, UserID, GroupID);
-    virtual void flush_writes() override;
+    virtual ErrorOr<void> flush_writes() override;
 
     BlockIndex first_block_index() const;
     BlockIndex first_block_of_block_group_descriptors() const;

Kernel/FileSystem/FileSystem.h

@@ -51,7 +51,7 @@ public:
         u8 file_type { 0 };
     };
 
-    virtual void flush_writes() { }
+    virtual ErrorOr<void> flush_writes() { return {}; }
 
     u64 logical_block_size() const { return m_logical_block_size; }
     size_t fragment_size() const { return m_fragment_size; }

Kernel/FileSystem/Inode.cpp

@@ -48,7 +48,11 @@ void Inode::sync()
 {
     if (is_metadata_dirty())
         (void)flush_metadata();
-    fs().flush_writes();
+    auto result = fs().flush_writes();
+    if (result.is_error()) {
+        // TODO: Figure out how to propagate error to a higher function.
+    }
+
 }
 
 ErrorOr<NonnullRefPtr<Custody>> Inode::resolve_as_link(Credentials const& credentials, Custody& base, RefPtr<Custody>* out_parent, int options, int symlink_recursion_level) const

Kernel/FileSystem/VirtualFileSystem.cpp

@@ -259,8 +259,12 @@ void VirtualFileSystem::sync_filesystems()
             file_systems.append(fs);
     });
 
-    for (auto& fs : file_systems)
-        fs->flush_writes();
+    for (auto& fs : file_systems) {
+        auto result = fs->flush_writes();
+        if (result.is_error()) {
+            //TODO: Figure out how to propagate error to a higher function.
+        }
+    }
 }
 
 void VirtualFileSystem::lock_all_filesystems()

Kernel/Tasks/PowerStateSwitchTask.cpp

@@ -106,7 +106,7 @@ ErrorOr<void> PowerStateSwitchTask::perform_shutdown(PowerStateSwitchTask::DoReb
 
         while (!mounts.is_empty()) {
             auto& mount = mounts.take_last();
-            mount.guest_fs().flush_writes();
+            TRY(mount.guest_fs().flush_writes());
 
             auto mount_path = TRY(mount.absolute_path());
             auto& mount_inode = mount.guest();