diff --git a/src/btree.rs b/src/btree.rs
index 1c5d278..afcf6bb 100644
--- a/src/btree.rs
+++ b/src/btree.rs
@@ -1,182 +1,215 @@
 use alloc::string::{String, ToString};
+use alloc::vec;
 use alloc::vec::Vec;
+use ondisk_btree::{BTree, FromBytes, SizeOf, ToBytes};
 use vapfs::{BlockDevice, Index};
+use crate::crc32;
+use crate::structs::Superblock;
 
 /// # BTd
 /// min-degree of all BTrees
 pub const BTd: u32 = 3;
 
-/// # BTKeyType
-/// key used to index a BTree
-pub type BTKeyType = u32;
-
-/// # BTKey
-/// whole value of a key in a BTree
-#[repr(C)]
-#[derive(Copy, Clone)]
-pub struct BTKey {
-    pub key: BTKeyType,
-    /// length of this entry in bytes
-    pub length: u32,
-    /// amount of files represented by this key, used in the case of hash collisions
-    pub count: u32,
-    /// if count is 1, this is the inode number of the file represented by this key
-    /// if count is >1, offset from first BTNode in bytes to an HCList struct
-    pub value: Index,
-    /// length of filename
-    /// zero if count is >1
-    pub filename_length: u32,
-    // rest of the struct is the filename
-}
-
-/// # HCList
-/// list of files represented by a single key in a BTree, used in the case of hash collisions
-#[repr(C)]
-#[derive(Copy, Clone)]
-pub struct HCList {
-    /// offset from first HCList in bytes to the next HCList
-    pub next: Index,
-    /// inode number of the file represented by this HCList
+/// # DirectoryListing
+/// an entry in a list of all files and directories sharing a common crc32 hash collision (unlikely to happen but just in case!)
+#[derive(Debug, Clone)]
+pub struct DirectoryListing {
+    pub name: String,
     pub inode: Index,
-    /// length of filename
-    pub filename_length: u32,
-    // rest of the struct is the filename
 }
 
-#[repr(C)]
-#[derive(Copy, Clone)]
-pub struct BTNode {
-    /// offset from first BTNode in bytes, each entry is a DirectoryKey
-    pub key_array: Index,
-    pub key_count: u32,
-    /// offset from first BTNode in bytes, each entry is another BTNode
-    pub child_array: Index,
-    pub child_count: u32,
+/// # BTreeEntry
+/// the aforementioned list, stored in a BTree
+#[derive(Debug, Clone, Default)]
+pub struct BTreeEntry {
+    pub crc32: u32,
+    pub entries: Vec<DirectoryListing>,
 }
 
-impl BTKey {
-    /// in-place conversion from the storage representation (big endian) to the native representation
-    pub fn convert_big_endian_to_native(&mut self) {
-        #[cfg(target_endian = "little")]
-        {
-            self.key = u32::from_be(self.key);
-            self.length = u32::from_be(self.length);
-            self.count = u32::from_be(self.count);
-            self.value = u64::from_be(self.value);
-            self.filename_length = u32::from_be(self.filename_length);
-        }
-    }
-
-    /// in-place conversion from the native representation to the storage representation (big endian)
-    pub fn convert_native_to_big_endian(&mut self) {
-        #[cfg(target_endian = "little")]
-        {
-            self.key = u32::to_be(self.key);
-            self.length = u32::to_be(self.length);
-            self.count = u32::to_be(self.count);
-            self.value = u64::to_be(self.value);
-            self.filename_length = u32::to_be(self.filename_length);
-        }
-    }
-
-    /// offset is from 0x0 in the block device to the beginning of the struct
-    pub fn read(offset: Index, bd: &mut dyn BlockDevice) -> Option<(Self, String)> {
-        let mut buf: [u8; core::mem::size_of::<Self>()] = [0; core::mem::size_of::<Self>()];
-        bd.seek(offset);
-        let read_count = bd.read_blocks(&mut buf);
-        if read_count < core::mem::size_of::<Self>() {
-            return None;
-        }
-        let mut key = unsafe { core::ptr::read(buf.as_ptr() as *const Self) };
-        key.convert_big_endian_to_native();
-        let filename = key.read_filename(offset, bd);
-        Some((key, filename))
-    }
-
-    /// offset is from 0x0 in the block device to the beginning of the struct
-    pub fn read_filename(&self, offset: Index, bd: &mut dyn BlockDevice) -> String {
-        let mut filename_buf: Vec<u8> = Vec::new();
-        filename_buf.resize(self.filename_length as usize, 0);
-        bd.seek(offset);
-        bd.read_blocks(&mut filename_buf);
-        String::from_utf8_lossy(unsafe { core::slice::from_raw_parts(filename_buf.as_ptr(), filename_buf.len()) }).to_string()
-    }
+/// # Directory
+/// a directory, containing a list of all files and directories in it
+#[derive(Clone)]
+pub struct Directory {
+    /// used in the case of b-tree corruption, to restore the b-tree
+    pub backup_entries: Vec<DirectoryListing>,
+    /// a crc32 hash of the b-tree
+    pub crc32: u32,
+    /// the b-tree
+    pub btree: BTree<BTreeEntry>,
 }
 
-impl BTNode {
-    pub const fn new(key_array: Index, key_count: u32, child_array: Index, child_count: u32) -> Self {
-        Self {
-            key_array,
-            key_count,
-            child_array,
-            child_count,
+impl Directory {
+    /// Reads the directory into memory from the given bytes
+    pub fn open(bytes: &[u8]) -> Self {
+        Self::from_bytes(bytes)
+    }
+
+    /// Converts the directory back into bytes for writing to disk
+    pub fn write(&self) -> Vec<u8> {
+        self.to_bytes()
+    }
+
+    /// Adds a new entry to the directory listing
+    pub fn new_entry(&mut self, name: &str, inode: Index) {
+        let crc32 = crc32::crc32(name.as_bytes());
+        // check if this crc32 hash already exists
+        let index = self.btree.search(crc32);
+        if let Some(node) = index {
+            if let Some(key) = node.keys.iter_mut().find(|key| key.0 == crc32) {
+                // if it does, add the new entry to the existing list
+                key.1.entries.push(DirectoryListing { name: name.to_string(), inode });
+            }
+        } else {
+            // if it doesn't, create a new list
+            let entries = vec![DirectoryListing { name: name.to_string(), inode }];
+            self.btree.insert(crc32, BTreeEntry { crc32, entries });
         }
     }
 
-    /// in-place conversion from the storage representation (big endian) to the native representation
-    pub fn convert_big_endian_to_native(&mut self) {
-        #[cfg(target_endian = "little")]
-        {
-            self.key_array = u64::from_be(self.key_array);
-            self.key_count = u32::from_be(self.key_count);
-            self.child_array = u64::from_be(self.child_array);
-            self.child_count = u32::from_be(self.child_count);
+    /// Returns an inode for the given entry name
+    pub fn find(&mut self, name: &str) -> Option<Index> {
+        let crc32 = crc32::crc32(name.as_bytes());
+        let index = self.btree.search(crc32);
+        if let Some(node) = index {
+            if let Some(key) = node.keys.iter().find(|key| key.0 == crc32) {
+                return Some(key.1.entries.iter().find(|entry| entry.name == name).unwrap().inode);
+            }
         }
+        None
     }
 
-    /// in-place conversion from the native representation to the storage representation (big endian)
-    pub fn convert_native_to_big_endian(&mut self) {
-        #[cfg(target_endian = "little")]
-        {
-            self.key_array = u64::to_be(self.key_array);
-            self.key_count = u32::to_be(self.key_count);
-            self.child_array = u64::to_be(self.child_array);
-            self.child_count = u32::to_be(self.child_count);
-        }
-    }
-
-    /// offset is from root in bytes
-    pub fn read(root: Index, offset: Index, bd: &mut dyn BlockDevice) -> Option<Self> {
-        let mut buf: [u8; core::mem::size_of::<Self>()] = [0; core::mem::size_of::<Self>()];
-        bd.seek(root + offset);
-        let read_count = bd.read_blocks(&mut buf);
-        if read_count < core::mem::size_of::<Self>() {
-            return None;
-        }
-        let mut node = unsafe { core::ptr::read(buf.as_ptr() as *const Self) };
-        node.convert_big_endian_to_native();
-        Some(node)
-    }
-
-    pub fn search(self, root: Index, key_to_find: BTKeyType, bd: &mut dyn BlockDevice) -> Option<(BTKey, String)> {
-        let mut node = self;
-        loop {
-            let mut i = 0;
-            let mut last_key: Option<BTKey> = None;
-            while i < node.key_count {
-                let key_offset = if i == 0 {
-                    node.key_array
-                } else {
-                    last_key.as_ref().unwrap().length as Index + last_key.as_ref().unwrap().value
-                };
-                let key = BTKey::read(key_offset, bd)?;
-                if key.0.key == key_to_find {
-                    return Some(key);
-                } else if key.0.key > key_to_find {
-                    break;
+    /// Removes an entry from the directory listing
+    pub fn remove_entry(&mut self, name: &str) {
+        let crc32 = crc32::crc32(name.as_bytes());
+        let index = self.btree.search(crc32);
+        if let Some(node) = index {
+            if let Some(key) = node.keys.iter_mut().find(|key| key.0 == crc32) {
+                key.1.entries.retain(|entry| entry.name != name);
+                if key.1.entries.is_empty() {
                 }
-                i += 1;
-                last_key = Some(key.0);
             }
-            if node.child_count == 0 {
-                return None;
-            }
-            let child_offset = if i == 0 {
-                node.child_array
-            } else {
-                last_key.unwrap().value
-            };
-            node = BTNode::read(root, child_offset, bd)?;
         }
     }
+
+    /// Returns a list of all entries in the directory
+    pub fn list(&mut self) -> Vec<DirectoryListing> {
+        let mut entries = Vec::new();
+        if let Some(root) = self.btree.root {
+            for entry in self.btree.traverse_in_order_values(root) {
+                entries.extend_from_slice(&entry.entries);
+            }
+        }
+        entries
+    }
+
+    /// Rebuilds the b-tree from the backup entries
+    pub fn rebuild(&mut self) {
+        self.btree = BTree::new(BTd);
+        for entry in &self.backup_entries {
+            let crc32 = crc32::crc32(entry.name.as_bytes());
+            let index = self.btree.search(crc32);
+            if let Some(node) = index {
+                if let Some(key) = node.keys.iter_mut().find(|key| key.0 == crc32) {
+                    key.1.entries.push(entry.clone());
+                }
+            } else {
+                let entries = vec![entry.clone()];
+                self.btree.insert(crc32, BTreeEntry { crc32, entries });
+            }
+        }
+    }
+}
+
+impl ToBytes for Directory {
+    fn to_bytes(&self) -> Vec<u8> {
+        let mut bytes = Vec::new();
+        bytes.extend_from_slice(&(self.backup_entries.len() as u32).to_be_bytes());
+        for entry in &self.backup_entries {
+            bytes.extend_from_slice(&(entry.size_of()).to_be_bytes());
+            bytes.extend_from_slice(&entry.to_bytes());
+        }
+        bytes.extend_from_slice(&self.crc32.to_be_bytes());
+        bytes.extend_from_slice(&self.btree.to_bytes());
+        bytes
+    }
+}
+
+impl FromBytes for Directory {
+    fn from_bytes(bytes: &[u8]) -> Self {
+        let backup_entry_count = u32::from_be_bytes(bytes[0..4].try_into().unwrap()) as usize;
+        let mut backup_entries = Vec::new();
+        let mut offset = 4;
+        for _ in 0..backup_entry_count {
+            let entry_size = u32::from_be_bytes(bytes[offset..offset + 4].try_into().unwrap()) as usize;
+            backup_entries.push(DirectoryListing::from_bytes(&bytes[offset + 4..offset + 4 + entry_size]));
+            offset += 4 + entry_size;
+        }
+        let crc32 = u32::from_be_bytes(bytes[offset..offset + 4].try_into().unwrap());
+        let btree = BTree::from_bytes(&bytes[offset + 4..]);
+        Self { backup_entries, crc32, btree }
+    }
+}
+
+impl ToBytes for DirectoryListing {
+    fn to_bytes(&self) -> Vec<u8> {
+        let mut bytes = Vec::new();
+        let name_len: u32 = self.name.len() as u32;
+        bytes.extend_from_slice(&name_len.to_be_bytes());
+        bytes.extend_from_slice(self.name.as_bytes());
+        bytes.extend_from_slice(&self.inode.to_be_bytes());
+        bytes
+    }
+}
+
+impl FromBytes for DirectoryListing {
+    fn from_bytes(bytes: &[u8]) -> Self {
+        let name_len = u32::from_be_bytes(bytes[0..4].try_into().unwrap()) as usize;
+        let name = String::from_utf8(bytes[4..4 + name_len].to_vec()).unwrap();
+        let inode = Index::from_be_bytes(bytes[4 + name_len..12 + name_len].try_into().unwrap());
+        Self { name, inode }
+    }
+}
+
+impl SizeOf for DirectoryListing {
+    fn size_of(&self) -> u32 {
+        4 + self.name.len() as u32 + 8
+    }
+}
+
+impl ToBytes for BTreeEntry {
+    fn to_bytes(&self) -> Vec<u8> {
+        let mut bytes = Vec::new();
+        bytes.extend_from_slice(&self.crc32.to_be_bytes());
+        bytes.extend_from_slice(&(self.entries.len() as u32).to_be_bytes());
+        for entry in &self.entries {
+            bytes.extend_from_slice(&(entry.size_of()).to_be_bytes());
+            bytes.extend_from_slice(&entry.to_bytes());
+        }
+        bytes
+    }
+}
+
+impl FromBytes for BTreeEntry {
+    fn from_bytes(bytes: &[u8]) -> Self {
+        let crc32 = u32::from_be_bytes(bytes[0..4].try_into().unwrap());
+        let entry_count = u32::from_be_bytes(bytes[4..8].try_into().unwrap()) as usize;
+        let mut entries = Vec::new();
+        let mut offset = 8;
+        for _ in 0..entry_count {
+            let entry_size = u32::from_be_bytes(bytes[offset..offset + 4].try_into().unwrap()) as usize;
+            entries.push(DirectoryListing::from_bytes(&bytes[offset + 4..offset + 4 + entry_size]));
+            offset += 4 + entry_size;
+        }
+        Self { crc32, entries }
+    }
+}
+
+impl SizeOf for BTreeEntry {
+    fn size_of(&self) -> u32 {
+        let mut size = 8;
+        for entry in &self.entries {
+            size += 4 + entry.size_of();
+        }
+        size
+    }
 }
\ No newline at end of file
diff --git a/src/lib.rs b/src/lib.rs
index fc1d702..b0aa940 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -12,6 +12,7 @@ pub mod btree;
 pub mod structs;
 pub mod bitmap;
 pub mod crc32;
+pub mod safe;
 
 /// Reads the superblock (located at byte offset 1024 of the block device) and returns it.
 /// Returns None if the block device is too small to contain a superblock.
@@ -1053,8 +1054,8 @@ pub fn flush_single_block_write(sb: &Superblock, bd: &mut dyn BlockDevice, entry
             }
             let mut inode = inode.unwrap();
             // target block is either an index into the direct blocks or an indirect block (if greater than 11)
-            if content.target_block < 12 {
-                let previous_block = inode.direct_block_addresses[content.target_block as usize];
+            if content.target_block < 32 {
+                let previous_block = inode.listblock.direct_block_addresses[content.target_block as usize];
 
                 // update the journal entry
                 journal_entry.content.block_write.real_target_block = previous_block;
@@ -1062,47 +1063,65 @@ pub fn flush_single_block_write(sb: &Superblock, bd: &mut dyn BlockDevice, entry
                     return false;
                 }
 
-                inode.direct_block_addresses[content.target_block as usize] = content.source_block;
+                inode.listblock.direct_block_addresses[content.target_block as usize] = content.source_block;
+
+                // if target_block is greater than block_count, we need to update block_count and the inode's byte count
+                if content.target_block >= inode.block_count {
+                    inode.block_count = content.target_block + 1;
+                    inode.size = inode.block_count * sb.block_size as u64;
+                    inode.listblock.count = inode.block_count;
+
+                    // note: we are assuming here that we are only increasing the size by 1,
+                    // greater size increases may result in weird corruption
+                    // (undefined dbas will be listed as part of the file, which will either result
+                    // in garbage data or leakage from another file)
+                    // fixme: in the future, we should check for this case and allocate blocks if needed
+                }
 
                 // update the inode
                 if !unsafe { write_inode(content.target_inode, sb, bd, inode) } {
                     return false;
                 }
             } else {
-                let conversion_needed = inode.flags & InodeFlags::INDIRECT as u32 == 0;
-
-                // figure out which indirect block we need to write to (either 1, 2, or 3)
-                // range 12..(12*2) is indirect block 1
-                // range (12*2)..(12*3) is indirect block 2
-                // range (12*3)..(12*4) is indirect block 3
-                let indirect_block_index = (content.target_block - 12) / 12;
-                let indirect_block_offset = (content.target_block - 12) % 12;
-                let indirect_block = inode.direct_block_addresses[indirect_block_index as usize];
-                let mut indirect_block_buf = read_datablock(indirect_block, sb, bd);
-                // get the count
-                let mut count = u64::from_be_bytes(indirect_block_buf.as_slice()[0..8].try_into().unwrap());
-                // place the source block at index (indirect_block_offset * 8) + 8
-                let target_index = (indirect_block_offset * 8) + 8;
-
-                // if there's already a block at the target index, we need to update the journal entry
-                if indirect_block_offset < count {
-                    // update the journal entry
-                    journal_entry.content.block_write.real_target_block = u64::from_be_bytes(indirect_block_buf.as_slice()[target_index as usize..(target_index + 8) as usize].try_into().unwrap());
-                    if !unsafe { write_journal_entry(entry_index, sb, bd, journal_entry) } {
-                        return false;
-                    }
-                }
-
-                indirect_block_buf.as_mut_slice()[target_index as usize..(target_index + 8) as usize].clone_from_slice(&content.source_block.to_be_bytes());
-                // update the count
-                if count < indirect_block_offset + 1 {
-                    count = indirect_block_offset + 1;
-                }
-                indirect_block_buf.as_mut_slice()[0..8].clone_from_slice(&count.to_be_bytes());
-                // write the indirect block back to the block device
-                if !unsafe { write_datablock(indirect_block, sb, bd, &indirect_block_buf) } {
+                let res = get_indirect_datablock(
+                    sb, bd, inode.listblock, content.target_block);
+                if res == None {
                     return false;
                 }
+                let (indirect_block_addr, indirect_block_index) = res.unwrap();
+                let mut indirect_block = read_datablock(indirect_block_addr, sb, bd);
+                let mut buf = [0u8; 8];
+                buf.copy_from_slice(&indirect_block[(indirect_block_index * 8) as usize..(indirect_block_index * 8 + 8) as usize]);
+                let previous_block = u64::from_be_bytes(buf);
+
+                // update the journal entry
+                journal_entry.content.block_write.real_target_block = previous_block;
+                if !unsafe { write_journal_entry(entry_index, sb, bd, journal_entry) } {
+                    return false;
+                }
+
+                // update the indirect block
+                buf.copy_from_slice(&content.source_block.to_be_bytes());
+                indirect_block[(indirect_block_index * 8) as usize..(indirect_block_index * 8 + 8) as usize].copy_from_slice(&buf);
+
+                if !unsafe { write_datablock(indirect_block_addr, sb, bd, &indirect_block) } {
+                    return false;
+                }
+
+                // if target_block is greater than block_count, we need to update block_count and the inode's byte count
+                if content.target_block >= inode.block_count {
+                    inode.block_count = content.target_block + 1;
+                    inode.size = inode.block_count * sb.block_size as u64;
+                    inode.listblock.count = inode.block_count;
+
+                    // note: see note above
+                }
+
+                // update the inode
+                if !unsafe { write_inode(content.target_inode, sb, bd, inode) } {
+                    return false;
+                }
+
             }
         } else if content.target_type == JBRTargetType::Disk as u32 {
             // copy the data directly to the offset on the disk
@@ -1251,10 +1270,9 @@ pub fn flush_multi_block_write(sb: &Superblock, bd: &mut dyn BlockDevice, entry_
         // get dbas of new list block
         let buf = read_datablock(content.list_block, sb, bd);
         let list_block = unsafe { core::ptr::read(buf.as_ptr() as *const ListBlock) };
-        let dba = list_block.direct_block_addresses;
         // update inode
         let mut inode = inode;
-        inode.direct_block_addresses = dba;
+        inode.listblock = list_block;
         if !unsafe { write_inode(content.target_inode, sb, bd, inode) } {
             return false;
         }
@@ -1277,48 +1295,275 @@ pub fn flush_multi_block_write(sb: &Superblock, bd: &mut dyn BlockDevice, entry_
         let old_list_block = read_datablock(content.old_list_block, sb, bd);
         let old_list_block = unsafe { core::ptr::read(old_list_block.as_ptr() as *const ListBlock) };
 
-        for i in 0..9 {
-            if old_list_block.direct_block_addresses[i] != 0 {
-                unused_datablocks.push(old_list_block.direct_block_addresses[i]);
+        let mut taken = 0;
+
+        for i in 0..32 {
+            if old_list_block.count > i {
+                unused_datablocks.push(old_list_block.direct_block_addresses[i as usize]);
+                taken += 1;
             }
         }
-        for x in 0..3 {
-            if !old_list_block.using_indirect_blocks {
-                unused_datablocks.push(old_list_block.direct_block_addresses[x + 9]);
-            } else {
-                // read indirect block
-                let mut deallocation_queue: Vec<Index> = Vec::new();
-                let mut buf = vec![];
-                let mut ptr = old_list_block.direct_block_addresses[x + 9];
-                deallocation_queue.push(ptr);
-                while !deallocation_queue.is_empty() {
-                    // read indirect block
-                    buf = read_datablock(ptr, sb, bd);
-                    let mut head = 0;
-                    let count = u64::from_be_bytes(buf[head..head + 8].try_into().unwrap()) as usize;
-                    head += 8;
-                    for i in 0..count {
-                        let is_data: bool = buf[head] != 0;
-                        let mut depth_no_data = buf[head..head + 8].to_vec();
-                        depth_no_data[0] = 0;
-                        let depth = u64::from_be_bytes(depth_no_data.try_into().unwrap()) as usize;
-                        head += 8;
-                        let new_ptr = u64::from_be_bytes(buf[head..head + 8].try_into().unwrap());
-                        if !is_data {
-                            deallocation_queue.push(new_ptr);
-                        } else {
-                            unused_datablocks.push(new_ptr);
-                        }
-                    }
-                    // deallocate this block
-                    unused_datablocks.push(ptr);
-                    // get next block
-                    if let Some(next_ptr) = deallocation_queue.pop() {
-                        ptr = next_ptr;
-                    } else {
+
+        let max_per_block = sb.block_size as u64 / 8;
+        let N = max_per_block * 32;
+        let N2 = N * N;
+        let N3 = N2 * N;
+        let N4 = N3 * N;
+        let N5 = N4 * N;
+        let N6 = N5 * N;
+
+        // enclosed to make collapsable
+        // todo! we should refactor this code eventually so that we don't have
+        // multi-hundred line long things cluttering everything like this
+        {
+            fn pushunused1(
+                sb: &Superblock, bd: &mut dyn BlockDevice, list_block: &[Index], old_count: usize,
+                unused_datablocks: &mut Vec<Index>, taken: &mut usize, max1: usize, max2: usize,
+                max_per_block: u64) -> bool {
+                for block2 in 0..max2 {
+                    if *taken >= old_count {
                         break;
                     }
+                    let buf = read_datablock(list_block[block2], sb, bd);
+                    let mut j = 0;
+                    let mut list = vec![0u64; max_per_block as usize];
+                    while j < max_per_block {
+                        if *taken + j as usize >= old_count {
+                            break;
+                        }
+                        let mut buf2 = [0u8; 8];
+                        buf2.copy_from_slice(&buf[j as usize * 8..(j * 8 + 8) as usize]);
+                        let dba = u64::from_be_bytes(buf2);
+                        if dba != 0 {
+                            list[j as usize] = dba;
+                        }
+                        j += 1;
+                    }
+                    for block1 in 0..max1 {
+                        if unused_datablocks.len() >= *taken {
+                            break;
+                        }
+                        let buf = read_datablock(list[block1], sb, bd);
+                        let mut j = 0;
+                        while j < max_per_block {
+                            if unused_datablocks.len() >= *taken {
+                                break;
+                            }
+                            let mut buf2 = [0u8; 8];
+                            buf2.copy_from_slice(&buf[j as usize * 8..(j * 8 + 8) as usize]);
+                            let dba = u64::from_be_bytes(buf2);
+                            if dba != 0 {
+                                unused_datablocks.push(dba);
+                                *taken += 1;
+                            }
+                            j += 1;
+                        }
+                    }
+                    unused_datablocks.push(list_block[block2]);
+                    *taken += 1;
                 }
+                true
+            }
+
+            // double indirect blocks
+            if !pushunused1(
+                sb, bd, &old_list_block.double_indirect_block_address, old_list_block.count as usize,
+                &mut unused_datablocks, &mut taken, max_per_block as usize, 32, max_per_block) {
+                return false;
+            }
+
+            // triple indirect blocks
+            fn pushunused2(
+                sb: &Superblock, bd: &mut dyn BlockDevice, list_block: &[Index], old_count: usize,
+                unused_datablocks: &mut Vec<Index>, taken: &mut usize, max1: usize, max2: usize,
+                max3: usize, max_per_block: u64) -> bool {
+                for block3 in 0..max3 {
+                    if *taken >= old_count {
+                        break;
+                    }
+                    let buf = read_datablock(list_block[block3], sb, bd);
+                    let mut j = 0;
+                    let mut list = vec![0u64; max_per_block as usize];
+                    while j < max_per_block {
+                        if *taken + j as usize >= old_count {
+                            break;
+                        }
+                        let mut buf2 = [0u8; 8];
+                        buf2.copy_from_slice(&buf[j as usize * 8..(j * 8 + 8) as usize]);
+                        let dba = u64::from_be_bytes(buf2);
+                        if dba != 0 {
+                            list[j as usize] = dba;
+                        }
+                        j += 1;
+                    }
+                    if !pushunused1(
+                        sb, bd, &list, old_count,
+                        unused_datablocks, taken, max1, max2, max_per_block) {
+                        return false;
+                    }
+                    unused_datablocks.push(list_block[block3]);
+                    *taken += 1;
+                }
+                true
+            }
+
+            if !pushunused2(
+                sb, bd, &old_list_block.triple_indirect_block_address, old_list_block.count as usize,
+                &mut unused_datablocks, &mut taken, max_per_block as usize, max_per_block as usize, 32, max_per_block) {
+                return false;
+            }
+
+            // quadruple indirect blocks
+            for block4 in 0..32 {
+                if taken >= old_list_block.count as usize {
+                    break;
+                }
+                let buf = read_datablock(old_list_block.quadruple_indirect_block_address[block4 as usize], sb, bd);
+                let mut j = 0;
+                let mut list = vec![0u64; max_per_block as usize];
+                while j < max_per_block {
+                    if taken >= old_list_block.count as usize {
+                        break;
+                    }
+                    let mut buf2 = [0u8; 8];
+                    buf2.copy_from_slice(&buf[j as usize * 8..(j * 8 + 8) as usize]);
+                    let dba = u64::from_be_bytes(buf2);
+                    if dba != 0 {
+                        list[j as usize] = dba;
+                    }
+                    j += 1;
+                }
+                if !pushunused2(
+                    sb, bd, &list, old_list_block.count as usize,
+                    &mut unused_datablocks, &mut taken, max_per_block as usize, max_per_block as usize, max_per_block as usize, max_per_block) {
+                    return false;
+                }
+                unused_datablocks.push(old_list_block.quadruple_indirect_block_address[block4 as usize]);
+                taken += 1;
+            }
+
+            // quintuple indirect blocks
+            for block5 in 0..32 {
+                if taken >= old_list_block.count as usize {
+                    break;
+                }
+                let buf = read_datablock(old_list_block.quintuple_indirect_block_address[block5 as usize], sb, bd);
+                let mut j = 0;
+                let mut list = vec![0u64; max_per_block as usize];
+                while j < max_per_block {
+                    if taken >= old_list_block.count as usize {
+                        break;
+                    }
+                    let mut buf2 = [0u8; 8];
+                    buf2.copy_from_slice(&buf[j as usize * 8..(j * 8 + 8) as usize]);
+                    let dba = u64::from_be_bytes(buf2);
+                    if dba != 0 {
+                        list[j as usize] = dba;
+                    }
+                    j += 1;
+                }
+                for block4 in 0..max_per_block {
+                    if taken >= old_list_block.count as usize {
+                        break;
+                    }
+                    let buf = read_datablock(list[block4 as usize], sb, bd);
+                    let mut j = 0;
+                    let mut list = vec![0u64; max_per_block as usize];
+                    while j < max_per_block {
+                        if taken >= old_list_block.count as usize {
+                            break;
+                        }
+                        let mut buf2 = [0u8; 8];
+                        buf2.copy_from_slice(&buf[j as usize * 8..(j * 8 + 8) as usize]);
+                        let dba = u64::from_be_bytes(buf2);
+                        if dba != 0 {
+                            list[j as usize] = dba;
+                        }
+                        j += 1;
+                    }
+                    if !pushunused2(
+                        sb, bd, &list, old_list_block.count as usize,
+                        &mut unused_datablocks, &mut taken, max_per_block as usize, max_per_block as usize, max_per_block as usize, max_per_block) {
+                        return false;
+                    }
+                    unused_datablocks.push(list[block4 as usize]);
+                    taken += 1;
+                }
+                unused_datablocks.push(old_list_block.quintuple_indirect_block_address[block5 as usize]);
+                taken += 1;
+            }
+
+            // sextuple indirect blocks
+            for block6 in 0..32 {
+                if taken >= old_list_block.count as usize {
+                    break;
+                }
+                let buf = read_datablock(old_list_block.sextuple_indirect_block_address[block6 as usize], sb, bd);
+                let mut j = 0;
+                let mut list = vec![0u64; max_per_block as usize];
+                while j < max_per_block {
+                    if taken >= old_list_block.count as usize {
+                        break;
+                    }
+                    let mut buf2 = [0u8; 8];
+                    buf2.copy_from_slice(&buf[j as usize * 8..(j * 8 + 8) as usize]);
+                    let dba = u64::from_be_bytes(buf2);
+                    if dba != 0 {
+                        list[j as usize] = dba;
+                    }
+                    j += 1;
+                }
+                for block5 in 0..max_per_block {
+                    if taken >= old_list_block.count as usize {
+                        break;
+                    }
+                    let buf = read_datablock(list[block5 as usize], sb, bd);
+                    let mut j = 0;
+                    let mut list = vec![0u64; max_per_block as usize];
+                    while j < max_per_block {
+                        if taken >= old_list_block.count as usize {
+                            break;
+                        }
+                        let mut buf2 = [0u8; 8];
+                        buf2.copy_from_slice(&buf[j as usize * 8..(j * 8 + 8) as usize]);
+                        let dba = u64::from_be_bytes(buf2);
+                        if dba != 0 {
+                            list[j as usize] = dba;
+                        }
+                        j += 1;
+                    }
+                    for block4 in 0..max_per_block {
+                        if taken >= old_list_block.count as usize {
+                            break;
+                        }
+                        let buf = read_datablock(list[block4 as usize], sb, bd);
+                        let mut j = 0;
+                        let mut list = vec![0u64; max_per_block as usize];
+                        while j < max_per_block {
+                            if taken >= old_list_block.count as usize {
+                                break;
+                            }
+                            let mut buf2 = [0u8; 8];
+                            buf2.copy_from_slice(&buf[j as usize * 8..(j * 8 + 8) as usize]);
+                            let dba = u64::from_be_bytes(buf2);
+                            if dba != 0 {
+                                list[j as usize] = dba;
+                            }
+                            j += 1;
+                        }
+                        if !pushunused2(
+                            sb, bd, &list, old_list_block.count as usize,
+                            &mut unused_datablocks, &mut taken, max_per_block as usize, max_per_block as usize, max_per_block as usize, max_per_block) {
+                            return false;
+                        }
+                        unused_datablocks.push(list[block4 as usize]);
+                        taken += 1;
+                    }
+                    unused_datablocks.push(list[block5 as usize]);
+                    taken += 1;
+                }
+                unused_datablocks.push(old_list_block.sextuple_indirect_block_address[block6 as usize]);
+                taken += 1;
             }
         }
 
diff --git a/src/safe.rs b/src/safe.rs
new file mode 100644
index 0000000..e69de29