diff --git a/src/reader/data.zig b/src/reader/data.zig
index 0edc749..8f6325e 100644
--- a/src/reader/data.zig
+++ b/src/reader/data.zig
@@ -10,19 +10,48 @@ const Compression = @import("../superblock.zig").Compression;
 const DataReaderError = error{
     EOF,
     InvalidIndex,
+    ExtractionActive,
 };
 
-const CompletionMap = struct{
+const DecompCompletion = struct {
     errs: std.ArrayList(anyerror),
     map: std.ArrayHashMap(usize, []u8),
     mut: std.Thread.Mutex = .{},
     cond: std.Thread.Condition = .{},
 
-    fn init(alloc: std.mem.Allocator) CompletionMap{
+    fn init(alloc: std.mem.Allocator) DecompCompletion {
         return .{
             .errs = .init(alloc),
-            .map = .init(alloc)
-        }
+            .map = .init(alloc),
+        };
+    }
+    fn deinit(self: *DecompCompletion) !void {
+        self.active = false;
+        self.errs.deinit();
+        self.map.deinit();
+    }
+
+    fn clear(self: *DecompCompletion) void {
+        self.errs.clearAndFree();
+        self.map.clearAndFree();
+    }
+
+    fn add(self: *DecompCompletion, idx: usize, data: []u8) !void {
+        self.mut.lock();
+        defer self.mut.unlock();
+        try self.map.put(idx, data);
+    }
+    fn addErr(self: *DecompCompletion, err: anyerror) void {
+        self.errs.append(err) catch {};
+    }
+
+    fn getBlock(self: *DecompCompletion, idx: usize) ?[]u8 {
+        const res = self.map.fetchSwapRemove(idx);
+        if(res == null) return null;
+        return res.?.value;
+    }
+    fn hasErrs(self: DecompCompletion) bool{
+        return self.errs.items.len > 0;
     }
 };
 
@@ -41,7 +70,7 @@ pub fn DataReader(comptime T: type) type {
 
         frag: ?[]u8 = null,
 
-        mut: std.Thread.Mutex = .{},
+        completion: DecompCompletion,
 
         pub fn init(rdr: *SfsReader(T), inode: Inode) !Self {
             var sizes: []BlockSize = undefined;
@@ -73,46 +102,43 @@ pub fn DataReader(comptime T: type) type {
                 .sizes = sizes,
                 .offsets = offsets,
                 .files_size = file_size,
+                .completion = .init(rdr.alloc),
             };
         }
-        pub fn deinit(self: Self) void {
+        pub fn deinit(self: *Self) void {
             self.alloc.free(self.offsets);
+            self.completion.deinit();
         }
 
-        pub fn addFragment(self: Self, data: []u8) void {
+        pub fn addFragment(self: *Self, data: []u8) void {
             self.frag = data;
         }
 
-        pub fn writeTo(self: Self, wrt: anytype) !void {
+        pub fn writeTo(self: *Self, wrt: anytype) !void {
             comptime std.debug.assert(std.meta.hasFn(@TypeOf(wrt), "write") or std.meta.hasFn(@TypeOf(wrt), "pwrite"));
-            var map: CompletionMap = .init(self.alloc);
-            defer map.deinit();
-            var mut: std.Thread.Mutex = .{};
-            var cond: std.Thread.Condition = .{};
-            var errs: std.ArrayList(anyerror) = .init(self.alloc);
-            defer errs.deinit();
             var write_thr = try std.Thread.spawn(
                 .{ .allocator = self.alloc },
                 writeThread,
-                .{ self, wrt, &errs, &map, &mut, &cond, null, null },
+                .{ self, wrt, null, null },
             );
+            defer self.completion.clear();
             for (0..self.numBlocks()) |i| {
                 var thr = std.Thread.spawn(
                     .{ .allocator = self.alloc },
                     decompThread,
-                    .{ self, i, &errs, &map, &mut, &cond },
+                    .{ self, i },
                 ) catch |err| {
-                    errs.append(err) catch {};
+                    self.completion.addErr(err);
                 };
                 thr.detach();
             }
             write_thr.join();
-            if (errs.items.len > 0) return errs.items[0];
+            if () return errs.items[0];
         }
 
         pub fn writeToNoBlock(self: Self, wrt: anytype, comptime finish: anytype, finish_args: anytype) !void {
             comptime std.debug.assert(std.meta.hasFn(@TypeOf(wrt), "write") or std.meta.hasFn(@TypeOf(wrt), "pwrite"));
-            var map: CompletionMap = .init(self.alloc);
+            var map: DecompCompletion = .init(self.alloc);
             errdefer map.deinit();
             var mut = try self.alloc.create(std.Thread.Mutex);
             errdefer self.alloc.destroy(mut);
@@ -139,7 +165,6 @@ pub fn DataReader(comptime T: type) type {
                 thr.detach();
             }
         }
-        fn writeToNoBlockFinish(comptime finish: anytype, finish_args: anytype) void {}
 
         fn numBlocks(self: Self) usize {
             var out = self.sizes.len;
@@ -177,7 +202,7 @@ pub fn DataReader(comptime T: type) type {
             self: Self,
             wrt: anytype,
             errs: *std.ArrayList(anyerror),
-            map: *CompletionMap,
+            map: *DecompCompletion,
             mut: *std.Thread.Mutex,
             cond: *std.Thread.Condition,
             comptime finish: anytype,
@@ -188,6 +213,7 @@ pub fn DataReader(comptime T: type) type {
             defer mut.unlock();
             while (cur_idx < self.numBlocks() and errs.items.len == 0) {
                 cond.wait(mut);
+                if (errs.items.len > 0) break;
                 if (comptime std.meta.hasFn(@TypeOf(wrt), "pwrite")) {
                     for (map.keys()) |k| {
                         const blk = map.fetchSwapRemove(k).?.value;
@@ -231,7 +257,7 @@ pub fn DataReader(comptime T: type) type {
             self: Self,
             idx: usize,
             errs: *std.ArrayList(anyerror),
-            map: *CompletionMap,
+            map: *DecompCompletion,
             mut: *std.Thread.Mutex,
             cond: *std.Thread.Condition,
         ) void {