diff --git a/Cargo.toml b/Cargo.toml
index a216e65..8330f1e 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -6,6 +6,7 @@ authors = ["Szymon Walter <walter.szymon.98@gmail.com>"]
 [dependencies]
 bitflags = "1.0"
 rlibc = { version = "1.0", optional = true }
+spin = "0.4"
 
 [features]
 default = ["no_std"]
diff --git a/src/fs/mod.rs b/src/fs/mod.rs
new file mode 100644
index 0000000..8feccfa
--- /dev/null
+++ b/src/fs/mod.rs
@@ -0,0 +1,171 @@
+use core::mem;
+
+use alloc::Vec;
+
+use error::Error;
+use sector::{Address, SectorSize};
+use volume::Volume;
+use sys::superblock::Superblock;
+use sys::block_group::BlockGroupDescriptor;
+use sys::inode::Inode as RawInode;
+
+pub mod sync;
+
+pub(crate) struct Struct<T, S: SectorSize> {
+    pub inner: T,
+    pub offset: Address<S>,
+}
+
+impl<T, S: SectorSize> From<(T, Address<S>)> for Struct<T, S> {
+    #[inline]
+    fn from((inner, offset): (T, Address<S>)) -> Struct<T, S> {
+        Struct { inner, offset }
+    }
+}
+
+/// Safe wrapper for raw sys structs
+pub struct Ext2<S: SectorSize, V: Volume<u8, S>> {
+    // TODO: should this have some different vis?
+    pub(crate) volume: V,
+    pub(crate) superblock: Struct<Superblock, S>,
+    pub(crate) block_groups: Struct<Vec<BlockGroupDescriptor>, S>,
+}
+
+impl<S: SectorSize, V: Volume<u8, S>> Ext2<S, V> {
+    pub fn new(volume: V) -> Result<Ext2<S, V>, Error> {
+        let superblock = unsafe { Struct::from(Superblock::find(&volume)?) };
+        let block_groups_offset = Address::with_block_size(
+            superblock.inner.first_data_block + 1,
+            0,
+            superblock.inner.log_block_size + 10,
+        );
+        let block_groups_count = superblock
+            .inner
+            .block_group_count()
+            .map(|count| count as usize)
+            .map_err(|(a, b)| Error::BadBlockGroupCount {
+                by_blocks: a,
+                by_inodes: b,
+            })?;
+        let block_groups = unsafe {
+            BlockGroupDescriptor::find_descriptor_table(
+                &volume,
+                block_groups_offset,
+                block_groups_count,
+            )?
+        };
+        let block_groups = Struct::from(block_groups);
+        Ok(Ext2 {
+            volume,
+            superblock,
+            block_groups,
+        })
+    }
+
+    pub fn version(&self) -> (u32, u16) {
+        (
+            self.superblock.inner.rev_major,
+            self.superblock.inner.rev_minor,
+        )
+    }
+
+    pub fn inode_size(&self) -> usize {
+        if self.version().0 == 0 {
+            mem::size_of::<RawInode>()
+        } else {
+            // note: inodes bigger than 128 are not supported
+            self.superblock.inner.inode_size as usize
+        }
+    }
+
+    pub fn inodes_count(&self) -> usize {
+        self.superblock.inner.inodes_per_group as _
+    }
+
+    pub fn total_inodes_count(&self) -> usize {
+        self.superblock.inner.inodes_count as _
+    }
+
+    pub fn block_group_count(&self) -> Result<usize, Error> {
+        self.superblock
+            .inner
+            .block_group_count()
+            .map(|count| count as usize)
+            .map_err(|(a, b)| Error::BadBlockGroupCount {
+                by_blocks: a,
+                by_inodes: b,
+            })
+    }
+
+    pub fn total_block_count(&self) -> usize {
+        self.superblock.inner.blocks_count as _
+    }
+
+    pub fn free_block_count(&self) -> usize {
+        self.superblock.inner.free_blocks_count as _
+    }
+
+    pub fn block_size(&self) -> usize {
+        self.superblock.inner.block_size()
+    }
+
+    pub fn log_block_size(&self) -> u32 {
+        self.superblock.inner.log_block_size + 10
+    }
+
+    pub fn sector_size(&self) -> usize {
+        S::SIZE
+    }
+
+    pub fn log_sector_size(&self) -> u32 {
+        S::LOG_SIZE
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::fs::File;
+    use std::cell::RefCell;
+
+    use sector::{Address, Size512};
+    use volume::Volume;
+
+    use super::Ext2;
+
+    #[test]
+    fn file_len() {
+        let file = RefCell::new(File::open("ext2.img").unwrap());
+        assert_eq!(
+            Address::<Size512>::from(2048_u64)
+                - Address::<Size512>::from(1024_u64),
+            Address::<Size512>::new(2, 0)
+        );
+        assert_eq!(
+            unsafe {
+                file.slice_unchecked(
+                    Address::<Size512>::from(1024_u64)
+                        ..Address::<Size512>::from(2048_u64),
+                ).len()
+            },
+            1024
+        );
+    }
+
+    #[test]
+    fn file() {
+        let file = RefCell::new(File::open("ext2.img").unwrap());
+        let fs = Ext2::<Size512, _>::new(file);
+
+        assert!(
+            fs.is_ok(),
+            "Err({:?})",
+            fs.err().unwrap_or_else(|| unreachable!()),
+        );
+
+        let fs = fs.unwrap();
+
+        let vers = fs.version();
+        println!("version: {}.{}", vers.0, vers.1);
+        assert_eq!(128, fs.inode_size());
+    }
+}
diff --git a/src/fs.rs b/src/fs/sync.rs
similarity index 57%
rename from src/fs.rs
rename to src/fs/sync.rs
index 17138a1..e9e0e00 100644
--- a/src/fs.rs
+++ b/src/fs/sync.rs
@@ -1,102 +1,155 @@
-use core::mem;
-use core::slice;
 use core::fmt::{self, Debug};
 use core::nonzero::NonZero;
 
 use alloc::Vec;
+use alloc::arc::Arc;
+
+use spin::{Mutex, MutexGuard};
 
 use error::Error;
 use sector::{Address, SectorSize};
-use volume::{Volume, VolumeSlice};
-use sys::superblock::Superblock;
-use sys::block_group::BlockGroupDescriptor;
+use volume::Volume;
 use sys::inode::Inode as RawInode;
 
-struct Struct<T, S: SectorSize> {
-    pub inner: T,
-    pub offset: Address<S>,
+use super::Ext2;
+
+pub struct Synced<T> {
+    inner: Arc<Mutex<T>>,
 }
 
-impl<T, S: SectorSize> From<(T, Address<S>)> for Struct<T, S> {
-    #[inline]
-    fn from((inner, offset): (T, Address<S>)) -> Struct<T, S> {
-        Struct { inner, offset }
+impl<T> Synced<T> {
+    pub fn with_inner(inner: T) -> Synced<T> {
+        Synced {
+            inner: Arc::new(Mutex::new(inner)),
+        }
+    }
+
+    pub fn inner<'a>(&'a self) -> MutexGuard<'a, T> {
+        self.inner.lock()
     }
 }
 
-/// Safe wrapper for raw sys structs
-pub struct Ext2<S: SectorSize, V: Volume<u8, S>> {
-    volume: V,
-    superblock: Struct<Superblock, S>,
-    block_groups: Struct<Vec<BlockGroupDescriptor>, S>,
+impl<T> Clone for Synced<T> {
+    fn clone(&self) -> Self {
+        Synced {
+            inner: self.inner.clone(),
+        }
+    }
 }
 
-impl<S: SectorSize, V: Volume<u8, S>> Ext2<S, V> {
-    pub fn new(volume: V) -> Result<Ext2<S, V>, Error> {
-        let superblock = unsafe { Struct::from(Superblock::find(&volume)?) };
-        let block_groups_offset = Address::with_block_size(
-            superblock.inner.first_data_block + 1,
-            0,
-            superblock.inner.log_block_size + 10,
-        );
-        let block_groups_count = superblock
-            .inner
-            .block_group_count()
-            .map(|count| count as usize)
-            .map_err(|(a, b)| Error::BadBlockGroupCount {
-                by_blocks: a,
-                by_inodes: b,
-            })?;
-        let block_groups = unsafe {
-            BlockGroupDescriptor::find_descriptor_table(
-                &volume,
-                block_groups_offset,
-                block_groups_count,
-            )?
-        };
-        let block_groups = Struct::from(block_groups);
-        Ok(Ext2 {
-            volume,
-            superblock,
-            block_groups,
-        })
+impl<S: SectorSize, V: Volume<u8, S>> Synced<Ext2<S, V>> {
+    pub fn new(volume: V) -> Result<Synced<Ext2<S, V>>, Error> {
+        Ext2::new(volume).map(|inner| Synced::with_inner(inner))
     }
 
-    #[allow(dead_code)]
-    fn update_global(&mut self) -> Result<(), Error> {
-        // superblock
-        {
-            let slice = VolumeSlice::from_cast(
-                &self.superblock.inner,
-                self.superblock.offset,
+    pub fn root_inode(&self) -> (Inode<S, V>, Address<S>) {
+        self.inode_nth(2).unwrap()
+    }
+
+    pub fn inode_nth(&self, index: usize) -> Option<(Inode<S, V>, Address<S>)> {
+        self.inodes_nth(index).next()
+    }
+
+    pub fn inodes(&self) -> Inodes<S, V> {
+        self.inodes_nth(1)
+    }
+
+    pub fn inodes_nth(&self, index: usize) -> Inodes<S, V> {
+        assert!(index > 0, "inodes are 1-indexed");
+        let inner = self.inner();
+        Inodes {
+            fs: self.clone(),
+            log_block_size: inner.log_block_size(),
+            inode_size: inner.inode_size(),
+            inodes_per_group: inner.inodes_count(),
+            inodes_count: inner.total_inodes_count(),
+            index,
+        }
+    }
+
+    pub fn sector_size(&self) -> usize {
+        S::SIZE
+    }
+
+    pub fn log_sector_size(&self) -> u32 {
+        S::LOG_SIZE
+    }
+}
+
+impl<S: SectorSize, V: Volume<u8, S>> Debug for Synced<Ext2<S, V>> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "Synced<Ext2<{}>>", S::SIZE)
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct Inodes<S: SectorSize, V: Volume<u8, S>> {
+    fs: Synced<Ext2<S, V>>,
+    log_block_size: u32,
+    inode_size: usize,
+    inodes_per_group: usize,
+    inodes_count: usize,
+    index: usize,
+}
+
+impl<S: SectorSize, V: Volume<u8, S>> Iterator for Inodes<S, V> {
+    type Item = (Inode<S, V>, Address<S>);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.index < self.inodes_count {
+            let block_group = (self.index - 1) / self.inodes_per_group;
+            let index = (self.index - 1) % self.inodes_per_group;
+            self.index += 1;
+
+            let fs = self.fs.inner();
+
+            let inodes_block =
+                fs.block_groups.inner[block_group].inode_table_block;
+
+            let offset = Address::with_block_size(
+                inodes_block,
+                (index * self.inode_size) as i32,
+                self.log_block_size,
             );
-            let commit = slice.commit();
-            self.volume.commit(commit).map_err(|err| err.into())?;
+            let raw = unsafe {
+                RawInode::find_inode(&fs.volume, offset, self.inode_size).ok()
+            };
+            raw.map(|(raw, offset)| (Inode::new(self.fs.clone(), raw), offset))
+        } else {
+            None
         }
+    }
+}
 
-        // block group descriptors
-        let mut offset = self.block_groups.offset;
-        for descr in &self.block_groups.inner {
-            let slice = VolumeSlice::from_cast(descr, offset);
-            let commit = slice.commit();
-            self.volume.commit(commit).map_err(|err| err.into())?;
-            offset =
-                offset + Address::from(mem::size_of::<BlockGroupDescriptor>());
+#[derive(Debug)]
+pub struct Inode<S: SectorSize, V: Volume<u8, S>> {
+    fs: Synced<Ext2<S, V>>,
+    inner: RawInode,
+}
+
+impl<S: SectorSize, V: Volume<u8, S>> Clone for Inode<S, V> {
+    fn clone(&self) -> Self {
+        Inode {
+            fs: self.fs.clone(),
+            inner: self.inner,
         }
+    }
+}
 
-        Ok(())
+impl<S: SectorSize, V: Volume<u8, S>> Inode<S, V> {
+    pub fn new(fs: Synced<Ext2<S, V>>, inner: RawInode) -> Inode<S, V> {
+        Inode { fs, inner }
     }
 
-    pub fn read_inode<'vol>(
-        &'vol self,
-        buf: &mut [u8],
-        inode: &Inode<'vol, S, V>,
-    ) -> Result<usize, Error> {
-        let total_size = inode.size();
-        let block_size = self.block_size();
+    pub fn read(&self, buf: &mut [u8]) -> Result<usize, Error> {
+        let total_size = self.size();
+        let block_size = {
+            let fs = self.fs.inner();
+            fs.block_size()
+        };
         let mut offset = 0;
 
-        for block in inode.blocks() {
+        for block in self.blocks() {
             match block {
                 Ok((data, _)) => {
                     let data_size = block_size
@@ -113,180 +166,24 @@ impl<S: SectorSize, V: Volume<u8, S>> Ext2<S, V> {
         Ok(offset)
     }
 
-    pub fn write_inode<'vol>(
-        &'vol self,
-        _inode: &(Inode<'vol, S, V>, Address<S>),
-        _buf: &[u8],
-    ) -> Result<usize, Error> {
-        unimplemented!()
-    }
-
-    pub fn root_inode<'vol>(&'vol self) -> (Inode<'vol, S, V>, Address<S>) {
-        self.inode_nth(2).unwrap()
-    }
-
-    pub fn inode_nth<'vol>(
-        &'vol self,
-        index: usize,
-    ) -> Option<(Inode<'vol, S, V>, Address<S>)> {
-        self.inodes_nth(index).next()
-    }
-
-    pub fn inodes<'vol>(&'vol self) -> Inodes<'vol, S, V> {
-        self.inodes_nth(1)
-    }
-
-    pub fn inodes_nth<'vol>(&'vol self, index: usize) -> Inodes<'vol, S, V> {
-        assert!(index > 0, "inodes are 1-indexed");
-        Inodes {
-            fs: self,
-            block_groups: &self.block_groups.inner,
-            log_block_size: self.log_block_size(),
-            inode_size: self.inode_size(),
-            inodes_per_group: self.inodes_count(),
-            inodes_count: self.total_inodes_count(),
-            index,
-        }
-    }
-
-    fn superblock(&self) -> &Superblock {
-        &self.superblock.inner
-    }
-
-    #[allow(dead_code)]
-    fn superblock_mut(&mut self) -> &mut Superblock {
-        &mut self.superblock.inner
-    }
-
-    pub fn version(&self) -> (u32, u16) {
-        (self.superblock().rev_major, self.superblock().rev_minor)
-    }
-
-    pub fn inode_size<'vol>(&'vol self) -> usize {
-        if self.version().0 == 0 {
-            mem::size_of::<Inode<'vol, S, V>>()
-        } else {
-            // note: inodes bigger than 128 are not supported
-            self.superblock().inode_size as usize
-        }
-    }
-
-    pub fn inodes_count(&self) -> usize {
-        self.superblock().inodes_per_group as _
-    }
-
-    pub fn total_inodes_count(&self) -> usize {
-        self.superblock().inodes_count as _
-    }
-
-    pub fn block_group_count(&self) -> Result<usize, Error> {
-        self.superblock()
-            .block_group_count()
-            .map(|count| count as usize)
-            .map_err(|(a, b)| Error::BadBlockGroupCount {
-                by_blocks: a,
-                by_inodes: b,
-            })
-    }
-
-    pub fn total_block_count(&self) -> usize {
-        self.superblock().blocks_count as _
-    }
-
-    pub fn free_block_count(&self) -> usize {
-        self.superblock().free_blocks_count as _
-    }
-
-    pub fn block_size(&self) -> usize {
-        self.superblock().block_size()
-    }
-
-    pub fn log_block_size(&self) -> u32 {
-        self.superblock().log_block_size + 10
-    }
-
-    pub fn sector_size(&self) -> usize {
-        S::SIZE
-    }
-
-    pub fn log_sector_size(&self) -> u32 {
-        S::LOG_SIZE
-    }
-}
-
-impl<S: SectorSize, V: Volume<u8, S>> Debug for Ext2<S, V> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "Ext2<{}>", S::SIZE)
-    }
-}
-
-pub struct Inodes<'vol, S: SectorSize, V: 'vol + Volume<u8, S>> {
-    fs: &'vol Ext2<S, V>,
-    block_groups: &'vol [BlockGroupDescriptor],
-    log_block_size: u32,
-    inode_size: usize,
-    inodes_per_group: usize,
-    inodes_count: usize,
-    index: usize,
-}
-
-impl<'vol, S: SectorSize, V: 'vol + Volume<u8, S>> Iterator
-    for Inodes<'vol, S, V>
-{
-    type Item = (Inode<'vol, S, V>, Address<S>);
-
-    fn next(&mut self) -> Option<Self::Item> {
-        if self.index < self.inodes_count {
-            let block_group = (self.index - 1) / self.inodes_per_group;
-            let index = (self.index - 1) % self.inodes_per_group;
-            self.index += 1;
-
-            let inodes_block = self.block_groups[block_group].inode_table_block;
-
-            let offset = Address::with_block_size(
-                inodes_block,
-                (index * self.inode_size) as i32,
-                self.log_block_size,
-            );
-            let raw = unsafe {
-                RawInode::find_inode(&self.fs.volume, offset, self.inode_size)
-                    .ok()
-            };
-            raw.map(|(raw, offset)| (Inode::new(self.fs, raw), offset))
-        } else {
-            None
-        }
-    }
-}
-
-#[derive(Debug, Clone)]
-pub struct Inode<'vol, S: SectorSize, V: 'vol + Volume<u8, S>> {
-    fs: &'vol Ext2<S, V>,
-    inner: RawInode,
-}
-
-impl<'vol, S: SectorSize, V: 'vol + Volume<u8, S>> Inode<'vol, S, V> {
-    pub fn new(fs: &'vol Ext2<S, V>, inner: RawInode) -> Inode<'vol, S, V> {
-        Inode { fs, inner }
-    }
-
-    pub fn blocks<'inode>(&'inode self) -> InodeBlocks<'vol, 'inode, S, V> {
+    pub fn blocks(&self) -> InodeBlocks<S, V> {
         InodeBlocks {
-            inode: self,
+            inode: self.clone(),
             index: 0,
         }
     }
 
-    pub fn directory<'inode>(
-        &'inode self,
-    ) -> Option<Directory<'vol, 'inode, S, V>> {
+    pub fn directory(&self) -> Option<Directory<S, V>> {
         use sys::inode::TypePerm;
         if unsafe { self.inner.type_perm.contains(TypePerm::DIRECTORY) } {
             Some(Directory {
                 blocks: self.blocks(),
                 offset: 0,
                 buffer: None,
-                block_size: self.fs.block_size(),
+                block_size: {
+                    let fs = self.fs.inner();
+                    fs.block_size()
+                },
             })
         } else {
             None
@@ -334,8 +231,10 @@ impl<'vol, S: SectorSize, V: 'vol + Volume<u8, S>> Inode<'vol, S, V> {
             }
         }
 
-        let bs4 = self.fs.block_size() / 4;
-        let log_block_size = self.fs.log_block_size();
+        let fs = self.fs.inner();
+
+        let bs4 = fs.block_size() / 4;
+        let log_block_size = fs.log_block_size();
 
         if index < 12 {
             return Ok(NonZero::new(self.inner.direct_pointer[index]));
@@ -345,7 +244,7 @@ impl<'vol, S: SectorSize, V: 'vol + Volume<u8, S>> Inode<'vol, S, V> {
 
         if index < bs4 {
             let block = self.inner.indirect_pointer;
-            return block_index(&self.fs.volume, block, index, log_block_size);
+            return block_index(&fs.volume, block, index, log_block_size);
         }
 
         index -= bs4;
@@ -353,7 +252,7 @@ impl<'vol, S: SectorSize, V: 'vol + Volume<u8, S>> Inode<'vol, S, V> {
         if index < bs4 * bs4 {
             let indirect_index = index >> (log_block_size + 2);
             let block = match block_index(
-                &self.fs.volume,
+                &fs.volume,
                 self.inner.doubly_indirect,
                 indirect_index,
                 log_block_size,
@@ -363,7 +262,7 @@ impl<'vol, S: SectorSize, V: 'vol + Volume<u8, S>> Inode<'vol, S, V> {
                 Err(err) => return Err(err),
             };
             return block_index(
-                &self.fs.volume,
+                &fs.volume,
                 block,
                 index & (bs4 - 1),
                 log_block_size,
@@ -375,7 +274,7 @@ impl<'vol, S: SectorSize, V: 'vol + Volume<u8, S>> Inode<'vol, S, V> {
         if index < bs4 * bs4 * bs4 {
             let doubly_index = index >> (2 * log_block_size + 4);
             let indirect = match block_index(
-                &self.fs.volume,
+                &fs.volume,
                 self.inner.triply_indirect,
                 doubly_index,
                 log_block_size,
@@ -386,7 +285,7 @@ impl<'vol, S: SectorSize, V: 'vol + Volume<u8, S>> Inode<'vol, S, V> {
             };
             let indirect_index = (index >> (log_block_size + 2)) & (bs4 - 1);
             let block = match block_index(
-                &self.fs.volume,
+                &fs.volume,
                 indirect as u32,
                 indirect_index,
                 log_block_size,
@@ -396,7 +295,7 @@ impl<'vol, S: SectorSize, V: 'vol + Volume<u8, S>> Inode<'vol, S, V> {
                 Err(err) => return Err(err),
             };
             return block_index(
-                &self.fs.volume,
+                &fs.volume,
                 block,
                 index & (bs4 - 1),
                 log_block_size,
@@ -439,20 +338,14 @@ impl<'vol, S: SectorSize, V: 'vol + Volume<u8, S>> Inode<'vol, S, V> {
     }
 }
 
-pub struct InodeBlocks<
-    'vol: 'inode,
-    'inode,
-    S: SectorSize,
-    V: 'vol + Volume<u8, S>,
-> {
-    inode: &'inode Inode<'vol, S, V>,
+#[derive(Debug, Clone)]
+pub struct InodeBlocks<S: SectorSize, V: Volume<u8, S>> {
+    inode: Inode<S, V>,
     index: usize,
 }
 
-impl<'vol, 'inode, S: SectorSize, V: 'vol + Volume<u8, S>> Iterator
-    for InodeBlocks<'vol, 'inode, S, V>
-{
-    type Item = Result<(VolumeSlice<'vol, u8, S>, Address<S>), Error>;
+impl<S: SectorSize, V: Volume<u8, S>> Iterator for InodeBlocks<S, V> {
+    type Item = Result<(Vec<u8>, Address<S>), Error>;
 
     fn next(&mut self) -> Option<Self::Item> {
         let block = self.inode.try_block(self.index);
@@ -463,38 +356,31 @@ impl<'vol, 'inode, S: SectorSize, V: 'vol + Volume<u8, S>> Iterator
         };
 
         self.index += 1;
+        let fs = self.inode.fs.inner();
 
         let block = block.get();
-        let log_block_size = self.inode.fs.log_block_size();
+        let log_block_size = fs.log_block_size();
         let offset = Address::with_block_size(block, 0, log_block_size);
         let end = Address::with_block_size(block + 1, 0, log_block_size);
 
-        let slice = self.inode
-            .fs
-            .volume
+        let slice = fs.volume
             .slice(offset..end)
-            .map(|slice| (slice, offset))
+            .map(|slice| (slice.to_vec(), offset))
             .map_err(|err| err.into());
         Some(slice)
     }
 }
 
-pub struct Directory<
-    'vol: 'inode,
-    'inode,
-    S: SectorSize,
-    V: 'vol + Volume<u8, S>,
-> {
-    blocks: InodeBlocks<'vol, 'inode, S, V>,
+#[derive(Debug, Clone)]
+pub struct Directory<S: SectorSize, V: Volume<u8, S>> {
+    blocks: InodeBlocks<S, V>,
     offset: usize,
-    buffer: Option<VolumeSlice<'vol, u8, S>>,
+    buffer: Option<Vec<u8>>,
     block_size: usize,
 }
 
-impl<'vol, 'inode, S: SectorSize, V: 'vol + Volume<u8, S>> Iterator
-    for Directory<'vol, 'inode, S, V>
-{
-    type Item = Result<DirectoryEntry<'vol>, Error>;
+impl<S: SectorSize, V: Volume<u8, S>> Iterator for Directory<S, V> {
+    type Item = Result<DirectoryEntry, Error>;
 
     fn next(&mut self) -> Option<Self::Item> {
         if self.buffer.is_none() || self.offset >= self.block_size {
@@ -520,8 +406,7 @@ impl<'vol, 'inode, S: SectorSize, V: 'vol + Volume<u8, S>> Iterator
         let len = buffer[6];
         let ty = buffer[7];
 
-        let ptr = unsafe { buffer.as_ptr().add(8) };
-        let name = unsafe { slice::from_raw_parts(ptr, len as usize) };
+        let name = buffer[8..8 + len as usize].to_vec();
 
         self.offset += size as usize;
 
@@ -533,8 +418,9 @@ impl<'vol, 'inode, S: SectorSize, V: 'vol + Volume<u8, S>> Iterator
     }
 }
 
-pub struct DirectoryEntry<'a> {
-    pub name: &'a [u8],
+#[derive(Clone)]
+pub struct DirectoryEntry {
+    pub name: Vec<u8>,
     pub inode: usize,
     pub ty: u8,
 }
@@ -544,34 +430,15 @@ mod tests {
     use std::fs::File;
     use std::cell::RefCell;
 
-    use sector::{Address, SectorSize, Size512};
+    use sector::{SectorSize, Size512};
     use volume::Volume;
 
-    use super::{Ext2, Inode};
-
-    #[test]
-    fn file_len() {
-        let file = RefCell::new(File::open("ext2.img").unwrap());
-        assert_eq!(
-            Address::<Size512>::from(2048_u64)
-                - Address::<Size512>::from(1024_u64),
-            Address::<Size512>::new(2, 0)
-        );
-        assert_eq!(
-            unsafe {
-                file.slice_unchecked(
-                    Address::<Size512>::from(1024_u64)
-                        ..Address::<Size512>::from(2048_u64),
-                ).len()
-            },
-            1024
-        );
-    }
+    use super::{Ext2, Inode, Synced};
 
     #[test]
     fn file() {
         let file = RefCell::new(File::open("ext2.img").unwrap());
-        let fs = Ext2::<Size512, _>::new(file);
+        let fs = Synced::<Ext2<Size512, _>>::new(file);
 
         assert!(
             fs.is_ok(),
@@ -580,16 +447,17 @@ mod tests {
         );
 
         let fs = fs.unwrap();
+        let inner = fs.inner();
 
-        let vers = fs.version();
+        let vers = inner.version();
         println!("version: {}.{}", vers.0, vers.1);
-        assert_eq!(128, fs.inode_size());
+        assert_eq!(128, inner.inode_size());
     }
 
     #[test]
     fn inodes() {
         let file = RefCell::new(File::open("ext2.img").unwrap());
-        let fs = Ext2::<Size512, _>::new(file);
+        let fs = Synced::<Ext2<Size512, _>>::new(file);
 
         assert!(
             fs.is_ok(),
@@ -609,7 +477,7 @@ mod tests {
     fn inode_blocks() {
         use std::str;
         let file = RefCell::new(File::open("ext2.img").unwrap());
-        let fs = Ext2::<Size512, _>::new(file).unwrap();
+        let fs = Synced::<Ext2<Size512, _>>::new(file).unwrap();
 
         let inodes = fs.inodes().filter(|inode| {
             inode.0.in_use() && inode.0.uid() == 1000 && inode.0.size() < 1024
@@ -619,7 +487,10 @@ mod tests {
             let size = inode.0.size();
             for block in inode.0.blocks() {
                 let (data, _) = block.unwrap();
-                assert_eq!(data.len(), fs.block_size());
+                assert_eq!(data.len(), {
+                    let fs = fs.inner();
+                    fs.block_size()
+                });
                 println!("{:?}", &data[..size]);
                 let _ = str::from_utf8(&data[..size])
                     .map(|string| println!("{}", string));
@@ -630,7 +501,7 @@ mod tests {
     #[test]
     fn read_inode() {
         let file = RefCell::new(File::open("ext2.img").unwrap());
-        let fs = Ext2::<Size512, _>::new(file).unwrap();
+        let fs = Synced::<Ext2<Size512, _>>::new(file).unwrap();
 
         let inodes = fs.inodes().filter(|inode| {
             inode.0.in_use() && inode.0.uid() == 1000 && inode.0.size() < 1024
@@ -640,7 +511,7 @@ mod tests {
             unsafe {
                 buf.set_len(inode.size());
             }
-            let size = fs.read_inode(&mut buf[..], &inode);
+            let size = inode.read(&mut buf[..]);
             assert!(size.is_ok());
             let size = size.unwrap();
             assert_eq!(size, inode.size());
@@ -653,7 +524,7 @@ mod tests {
     #[test]
     fn read_big() {
         let file = RefCell::new(File::open("ext2.img").unwrap());
-        let fs = Ext2::<Size512, _>::new(file).unwrap();
+        let fs = Synced::<Ext2<Size512, _>>::new(file).unwrap();
 
         let inodes = fs.inodes().filter(|inode| {
             inode.0.in_use() && inode.0.uid() == 1000
@@ -664,7 +535,7 @@ mod tests {
             unsafe {
                 buf.set_len(inode.size());
             }
-            let size = fs.read_inode(&mut buf[..], &inode);
+            let size = inode.read(&mut buf[..]);
             assert!(size.is_ok());
             let size = size.unwrap();
             assert_eq!(size, inode.size());
@@ -687,15 +558,15 @@ mod tests {
         use std::str;
 
         fn walk<'vol, S: SectorSize, V: Volume<u8, S>>(
-            fs: &'vol Ext2<S, V>,
-            inode: Inode<'vol, S, V>,
+            fs: &'vol Synced<Ext2<S, V>>,
+            inode: Inode<S, V>,
             name: String,
         ) {
             inode.directory().map(|dir| {
                 for entry in dir {
                     assert!(entry.is_ok());
                     let entry = entry.unwrap();
-                    let entry_name = str::from_utf8(entry.name).unwrap_or("?");
+                    let entry_name = str::from_utf8(&entry.name).unwrap_or("?");
                     println!("{}/{} => {}", name, entry_name, entry.inode,);
                     if entry_name != "." && entry_name != ".." {
                         walk(
@@ -709,7 +580,7 @@ mod tests {
         }
 
         let file = RefCell::new(File::open("ext2.img").unwrap());
-        let fs = Ext2::<Size512, _>::new(file).unwrap();
+        let fs = Synced::<Ext2<Size512, _>>::new(file).unwrap();
 
         let (root, _) = fs.root_inode();
         walk(&fs, root, String::new());
diff --git a/src/lib.rs b/src/lib.rs
index 3b3be42..f6e749d 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -12,6 +12,7 @@
 extern crate alloc;
 #[macro_use]
 extern crate bitflags;
+extern crate spin;
 
 #[cfg(any(test, not(feature = "no_std")))]
 extern crate core;
diff --git a/src/volume/mod.rs b/src/volume/mod.rs
index c5eaebf..f1b08e3 100644
--- a/src/volume/mod.rs
+++ b/src/volume/mod.rs
@@ -31,6 +31,7 @@ pub trait Volume<T: Clone, S: SectorSize> {
     ) -> Result<VolumeSlice<'a, T, S>, Self::Error>;
 }
 
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub struct VolumeSlice<'a, T: 'a + Clone, S: SectorSize> {
     inner: Cow<'a, [T]>,
     index: Address<S>,