diff --git a/src/cache/dump.rs b/src/cache/dump.rs
index a3685f5..c5c33c1 100644
--- a/src/cache/dump.rs
+++ b/src/cache/dump.rs
@@ -7,9 +7,10 @@ use std::path::Path;
 use std::sync::{Arc, Mutex};
 
 use crate::cache::hint::Hint;
+use crate::cache::ir::{self, MetadataVisitor};
 use crate::cache::mapping::Mapping;
 use crate::cache::superblock::*;
-use crate::cache::xml::{self, MetadataVisitor};
+use crate::cache::xml;
 use crate::io_engine::{AsyncIoEngine, IoEngine, SyncIoEngine};
 use crate::pdata::array::{self, ArrayBlock};
 use crate::pdata::array_walker::*;
@@ -58,7 +59,7 @@ mod format1 {
                     continue;
                 }
 
-                let m = xml::Map {
+                let m = ir::Map {
                     cblock,
                     oblock: map.oblock,
                     dirty: map.is_dirty(),
@@ -133,7 +134,7 @@ mod format2 {
                     // default to dirty if the bitset is damaged
                     dirty = true;
                 }
-                let m = xml::Map {
+                let m = ir::Map {
                     cblock,
                     oblock: map.oblock,
                     dirty,
@@ -175,7 +176,7 @@ impl<'a> ArrayVisitor<Hint> for HintEmitter<'a> {
                 continue;
             }
 
-            let h = xml::Hint {
+            let h = ir::Hint {
                 cblock,
                 data: hint.hint.to_vec(),
             };
@@ -226,7 +227,7 @@ fn dump_metadata(
     let engine = &ctx.engine;
 
     let mut out = xml::XmlWriter::new(w);
-    let xml_sb = xml::Superblock {
+    let xml_sb = ir::Superblock {
         uuid: "".to_string(),
         block_size: sb.data_block_size,
         nr_cache_blocks: sb.cache_blocks,
diff --git a/src/cache/ir.rs b/src/cache/ir.rs
new file mode 100644
index 0000000..65be4aa
--- /dev/null
+++ b/src/cache/ir.rs
@@ -0,0 +1,60 @@
+use anyhow::Result;
+
+//------------------------------------------
+
+#[derive(Clone)]
+pub struct Superblock {
+    pub uuid: String,
+    pub block_size: u32,
+    pub nr_cache_blocks: u32,
+    pub policy: String,
+    pub hint_width: u32,
+}
+
+#[derive(Clone)]
+pub struct Map {
+    pub cblock: u32,
+    pub oblock: u64,
+    pub dirty: bool,
+}
+
+#[derive(Clone)]
+pub struct Hint {
+    pub cblock: u32,
+    pub data: Vec<u8>,
+}
+
+#[derive(Clone)]
+pub struct Discard {
+    pub begin: u64,
+    pub end: u64,
+}
+
+//------------------------------------------
+
+#[derive(Clone)]
+pub enum Visit {
+    Continue,
+    Stop,
+}
+
+pub trait MetadataVisitor {
+    fn superblock_b(&mut self, sb: &Superblock) -> Result<Visit>;
+    fn superblock_e(&mut self) -> Result<Visit>;
+
+    fn mappings_b(&mut self) -> Result<Visit>;
+    fn mappings_e(&mut self) -> Result<Visit>;
+    fn mapping(&mut self, m: &Map) -> Result<Visit>;
+
+    fn hints_b(&mut self) -> Result<Visit>;
+    fn hints_e(&mut self) -> Result<Visit>;
+    fn hint(&mut self, h: &Hint) -> Result<Visit>;
+
+    fn discards_b(&mut self) -> Result<Visit>;
+    fn discards_e(&mut self) -> Result<Visit>;
+    fn discard(&mut self, d: &Discard) -> Result<Visit>;
+
+    fn eof(&mut self) -> Result<Visit>;
+}
+
+//------------------------------------------
diff --git a/src/cache/mod.rs b/src/cache/mod.rs
index ceb8867..c01cc6c 100644
--- a/src/cache/mod.rs
+++ b/src/cache/mod.rs
@@ -1,6 +1,7 @@
 pub mod check;
 pub mod dump;
 pub mod hint;
+pub mod ir;
 pub mod mapping;
 pub mod restore;
 pub mod superblock;
diff --git a/src/cache/restore.rs b/src/cache/restore.rs
index e7ab5cd..5d5f23c 100644
--- a/src/cache/restore.rs
+++ b/src/cache/restore.rs
@@ -7,9 +7,10 @@ use std::path::Path;
 use std::sync::Arc;
 
 use crate::cache::hint::Hint;
+use crate::cache::ir::{self, MetadataVisitor, Visit};
 use crate::cache::mapping::{Mapping, MappingFlags};
 use crate::cache::superblock::*;
-use crate::cache::xml::{self, MetadataVisitor, Visit};
+use crate::cache::xml;
 use crate::io_engine::*;
 use crate::math::*;
 use crate::pdata::array_builder::*;
@@ -56,7 +57,7 @@ fn mk_context(opts: &CacheRestoreOptions) -> anyhow::Result<Context> {
 //------------------------------------------
 
 struct RestoreResult {
-    sb: xml::Superblock,
+    sb: ir::Superblock,
     mapping_root: u64,
     dirty_root: Option<u64>,
     hint_root: u64,
@@ -65,7 +66,7 @@ struct RestoreResult {
 
 struct Restorer<'a> {
     write_batcher: &'a mut WriteBatcher,
-    sb: Option<xml::Superblock>,
+    sb: Option<ir::Superblock>,
     mapping_builder: Option<ArrayBuilder<Mapping>>,
     dirty_builder: Option<ArrayBuilder<u64>>,
     hint_builder: Option<ArrayBuilder<Hint>>,
@@ -112,7 +113,7 @@ impl<'a> Restorer<'a> {
 }
 
 impl<'a> MetadataVisitor for Restorer<'a> {
-    fn superblock_b(&mut self, sb: &xml::Superblock) -> Result<Visit> {
+    fn superblock_b(&mut self, sb: &ir::Superblock) -> Result<Visit> {
         self.sb = Some(sb.clone());
         self.write_batcher.alloc()?;
         self.mapping_builder = Some(ArrayBuilder::new(sb.nr_cache_blocks as u64));
@@ -157,7 +158,7 @@ impl<'a> MetadataVisitor for Restorer<'a> {
         Ok(Visit::Continue)
     }
 
-    fn mapping(&mut self, m: &xml::Map) -> Result<Visit> {
+    fn mapping(&mut self, m: &ir::Map) -> Result<Visit> {
         let map = Mapping {
             oblock: m.oblock,
             flags: MappingFlags::Valid as u32,
@@ -198,7 +199,7 @@ impl<'a> MetadataVisitor for Restorer<'a> {
         Ok(Visit::Continue)
     }
 
-    fn hint(&mut self, h: &xml::Hint) -> Result<Visit> {
+    fn hint(&mut self, h: &ir::Hint) -> Result<Visit> {
         let hint = Hint {
             hint: h.data[..].try_into().unwrap(),
         };
@@ -215,7 +216,7 @@ impl<'a> MetadataVisitor for Restorer<'a> {
         Ok(Visit::Continue)
     }
 
-    fn discard(&mut self, _d: &xml::Discard) -> Result<Visit> {
+    fn discard(&mut self, _d: &ir::Discard) -> Result<Visit> {
         Ok(Visit::Continue)
     }
 
diff --git a/src/cache/xml.rs b/src/cache/xml.rs
index 6a05744..f171151 100644
--- a/src/cache/xml.rs
+++ b/src/cache/xml.rs
@@ -6,63 +6,11 @@ use std::io::{Read, Write};
 use quick_xml::events::{BytesEnd, BytesStart, Event};
 use quick_xml::{Reader, Writer};
 
+use crate::cache::ir::*;
 use crate::xml::*;
 
 //---------------------------------------
 
-#[derive(Clone)]
-pub struct Superblock {
-    pub uuid: String,
-    pub block_size: u32,
-    pub nr_cache_blocks: u32,
-    pub policy: String,
-    pub hint_width: u32,
-}
-
-#[derive(Clone)]
-pub struct Map {
-    pub cblock: u32,
-    pub oblock: u64,
-    pub dirty: bool,
-}
-
-#[derive(Clone)]
-pub struct Hint {
-    pub cblock: u32,
-    pub data: Vec<u8>,
-}
-
-#[derive(Clone)]
-pub struct Discard {
-    pub begin: u64,
-    pub end: u64,
-}
-
-#[derive(Clone)]
-pub enum Visit {
-    Continue,
-    Stop,
-}
-
-pub trait MetadataVisitor {
-    fn superblock_b(&mut self, sb: &Superblock) -> Result<Visit>;
-    fn superblock_e(&mut self) -> Result<Visit>;
-
-    fn mappings_b(&mut self) -> Result<Visit>;
-    fn mappings_e(&mut self) -> Result<Visit>;
-    fn mapping(&mut self, m: &Map) -> Result<Visit>;
-
-    fn hints_b(&mut self) -> Result<Visit>;
-    fn hints_e(&mut self) -> Result<Visit>;
-    fn hint(&mut self, h: &Hint) -> Result<Visit>;
-
-    fn discards_b(&mut self) -> Result<Visit>;
-    fn discards_e(&mut self) -> Result<Visit>;
-    fn discard(&mut self, d: &Discard) -> Result<Visit>;
-
-    fn eof(&mut self) -> Result<Visit>;
-}
-
 pub struct XmlWriter<W: Write> {
     w: Writer<W>,
 }
diff --git a/src/shrink/toplevel.rs b/src/shrink/toplevel.rs
index e7cde54..fb47773 100644
--- a/src/shrink/toplevel.rs
+++ b/src/shrink/toplevel.rs
@@ -6,7 +6,8 @@ use std::os::unix::fs::OpenOptionsExt;
 use std::path::Path;
 
 use crate::shrink::copier::{self, Region};
-use crate::thin::xml::{self, Visit};
+use crate::thin::ir::{self, MetadataVisitor, Visit};
+use crate::thin::xml;
 
 //---------------------------------------
 
@@ -34,8 +35,8 @@ impl Pass1 {
     }
 }
 
-impl xml::MetadataVisitor for Pass1 {
-    fn superblock_b(&mut self, sb: &xml::Superblock) -> Result<Visit> {
+impl MetadataVisitor for Pass1 {
+    fn superblock_b(&mut self, sb: &ir::Superblock) -> Result<Visit> {
         self.allocated_blocks.grow(sb.nr_data_blocks as usize);
         self.block_size = Some(sb.data_block_size as u64);
         Ok(Visit::Continue)
@@ -53,7 +54,7 @@ impl xml::MetadataVisitor for Pass1 {
         todo!();
     }
 
-    fn device_b(&mut self, _d: &xml::Device) -> Result<Visit> {
+    fn device_b(&mut self, _d: &ir::Device) -> Result<Visit> {
         Ok(Visit::Continue)
     }
 
@@ -61,7 +62,7 @@ impl xml::MetadataVisitor for Pass1 {
         Ok(Visit::Continue)
     }
 
-    fn map(&mut self, m: &xml::Map) -> Result<Visit> {
+    fn map(&mut self, m: &ir::Map) -> Result<Visit> {
         for i in m.data_begin..(m.data_begin + m.len) {
             if i > self.nr_blocks {
                 self.nr_high_blocks += 1;
@@ -99,8 +100,8 @@ impl<W: Write> Pass2<W> {
     }
 }
 
-impl<W: Write> xml::MetadataVisitor for Pass2<W> {
-    fn superblock_b(&mut self, sb: &xml::Superblock) -> Result<Visit> {
+impl<W: Write> MetadataVisitor for Pass2<W> {
+    fn superblock_b(&mut self, sb: &ir::Superblock) -> Result<Visit> {
         self.writer.superblock_b(sb)
     }
 
@@ -116,7 +117,7 @@ impl<W: Write> xml::MetadataVisitor for Pass2<W> {
         todo!();
     }
 
-    fn device_b(&mut self, d: &xml::Device) -> Result<Visit> {
+    fn device_b(&mut self, d: &ir::Device) -> Result<Visit> {
         self.writer.device_b(d)
     }
 
@@ -124,7 +125,7 @@ impl<W: Write> xml::MetadataVisitor for Pass2<W> {
         self.writer.device_e()
     }
 
-    fn map(&mut self, m: &xml::Map) -> Result<Visit> {
+    fn map(&mut self, m: &ir::Map) -> Result<Visit> {
         if m.data_begin + m.len < self.nr_blocks {
             // no remapping needed.
             self.writer.map(m)?;
@@ -134,7 +135,7 @@ impl<W: Write> xml::MetadataVisitor for Pass2<W> {
             let mut written = 0;
 
             for r in remaps {
-                self.writer.map(&xml::Map {
+                self.writer.map(&ir::Map {
                     thin_begin: m.thin_begin + written,
                     data_begin: r.start,
                     time: m.time,
@@ -493,7 +494,7 @@ fn build_copy_regions(remaps: &[(BlockRange, BlockRange)], block_size: u64) -> V
     rs
 }
 
-fn process_xml<MV: xml::MetadataVisitor>(input_path: &Path, pass: &mut MV) -> Result<()> {
+fn process_xml<MV: MetadataVisitor>(input_path: &Path, pass: &mut MV) -> Result<()> {
     let input = OpenOptions::new()
         .read(true)
         .write(false)
diff --git a/src/thin/dump.rs b/src/thin/dump.rs
index aa5942e..7296dfb 100644
--- a/src/thin/dump.rs
+++ b/src/thin/dump.rs
@@ -18,14 +18,15 @@ use crate::pdata::unpack::*;
 use crate::report::*;
 use crate::thin::block_time::*;
 use crate::thin::device_detail::*;
+use crate::thin::ir::{self, MetadataVisitor};
 use crate::thin::runs::*;
 use crate::thin::superblock::*;
-use crate::thin::xml::{self, MetadataVisitor};
+use crate::thin::xml;
 
 //------------------------------------------
 
 struct RunBuilder {
-    run: Option<xml::Map>,
+    run: Option<ir::Map>,
 }
 
 impl RunBuilder {
@@ -33,12 +34,12 @@ impl RunBuilder {
         RunBuilder { run: None }
     }
 
-    fn next(&mut self, thin_block: u64, data_block: u64, time: u32) -> Option<xml::Map> {
-        use xml::Map;
+    fn next(&mut self, thin_block: u64, data_block: u64, time: u32) -> Option<ir::Map> {
+        use ir::Map;
 
         match self.run {
             None => {
-                self.run = Some(xml::Map {
+                self.run = Some(ir::Map {
                     thin_begin: thin_block,
                     data_begin: data_block,
                     time,
@@ -46,7 +47,7 @@ impl RunBuilder {
                 });
                 None
             }
-            Some(xml::Map {
+            Some(ir::Map {
                 thin_begin,
                 data_begin,
                 time: mtime,
@@ -70,7 +71,7 @@ impl RunBuilder {
         }
     }
 
-    fn complete(&mut self) -> Option<xml::Map> {
+    fn complete(&mut self) -> Option<ir::Map> {
         self.run.take()
     }
 }
@@ -78,7 +79,7 @@ impl RunBuilder {
 //------------------------------------------
 
 struct MVInner<'a> {
-    md_out: &'a mut dyn xml::MetadataVisitor,
+    md_out: &'a mut dyn MetadataVisitor,
     builder: RunBuilder,
 }
 
@@ -89,7 +90,7 @@ struct MappingVisitor<'a> {
 //------------------------------------------
 
 impl<'a> MappingVisitor<'a> {
-    fn new(md_out: &'a mut dyn xml::MetadataVisitor) -> MappingVisitor<'a> {
+    fn new(md_out: &'a mut dyn MetadataVisitor) -> MappingVisitor<'a> {
         MappingVisitor {
             inner: Mutex::new(MVInner {
                 md_out,
@@ -516,7 +517,7 @@ where
     Ok(())
 }
 
-fn emit_leaves(ctx: &Context, out: &mut dyn xml::MetadataVisitor, ls: &[u64]) -> Result<()> {
+fn emit_leaves(ctx: &Context, out: &mut dyn MetadataVisitor, ls: &[u64]) -> Result<()> {
     let mut v = MappingVisitor::new(out);
     let proc = |b| {
         emit_leaf(&mut v, &b)?;
@@ -560,9 +561,9 @@ fn emit_entries<W: Write>(
 fn dump_metadata(ctx: &Context, w: &mut dyn Write, sb: &Superblock, md: &Metadata) -> Result<()> {
     let data_root = unpack::<SMRoot>(&sb.data_sm_root[0..])?;
     let mut out = xml::XmlWriter::new(w);
-    let xml_sb = xml::Superblock {
+    let xml_sb = ir::Superblock {
         uuid: "".to_string(),
-        time: sb.time as u64,
+        time: sb.time,
         transaction: sb.transaction_id,
         flags: None,
         version: Some(2),
@@ -581,12 +582,12 @@ fn dump_metadata(ctx: &Context, w: &mut dyn Write, sb: &Superblock, md: &Metadat
 
     ctx.report.set_title("Dumping devices");
     for dev in &md.devs {
-        let device = xml::Device {
+        let device = ir::Device {
             dev_id: dev.thin_id,
             mapped_blocks: dev.detail.mapped_blocks,
             transaction: dev.detail.transaction_id,
-            creation_time: dev.detail.creation_time as u64,
-            snap_time: dev.detail.snapshotted_time as u64,
+            creation_time: dev.detail.creation_time,
+            snap_time: dev.detail.snapshotted_time,
         };
         out.device_b(&device)?;
         emit_entries(ctx, &mut out, &dev.map.entries)?;
diff --git a/src/thin/ir.rs b/src/thin/ir.rs
new file mode 100644
index 0000000..ed4aa26
--- /dev/null
+++ b/src/thin/ir.rs
@@ -0,0 +1,60 @@
+use anyhow::Result;
+
+//------------------------------------------
+
+#[derive(Clone)]
+pub struct Superblock {
+    pub uuid: String,
+    pub time: u32,
+    pub transaction: u64,
+    pub flags: Option<u32>,
+    pub version: Option<u32>,
+    pub data_block_size: u32,
+    pub nr_data_blocks: u64,
+    pub metadata_snap: Option<u64>,
+}
+
+#[derive(Clone)]
+pub struct Device {
+    pub dev_id: u32,
+    pub mapped_blocks: u64,
+    pub transaction: u64,
+    pub creation_time: u32,
+    pub snap_time: u32,
+}
+
+#[derive(Clone)]
+pub struct Map {
+    pub thin_begin: u64,
+    pub data_begin: u64,
+    pub time: u32,
+    pub len: u64,
+}
+
+//------------------------------------------
+
+#[derive(Clone)]
+pub enum Visit {
+    Continue,
+    Stop,
+}
+
+pub trait MetadataVisitor {
+    fn superblock_b(&mut self, sb: &Superblock) -> Result<Visit>;
+    fn superblock_e(&mut self) -> Result<Visit>;
+
+    // Defines a shared sub tree.  May only contain a 'map' (no 'ref' allowed).
+    fn def_shared_b(&mut self, name: &str) -> Result<Visit>;
+    fn def_shared_e(&mut self) -> Result<Visit>;
+
+    // A device contains a number of 'map' or 'ref' items.
+    fn device_b(&mut self, d: &Device) -> Result<Visit>;
+    fn device_e(&mut self) -> Result<Visit>;
+
+    fn map(&mut self, m: &Map) -> Result<Visit>;
+    fn ref_shared(&mut self, name: &str) -> Result<Visit>;
+
+    fn eof(&mut self) -> Result<Visit>;
+}
+
+//------------------------------------------
diff --git a/src/thin/mod.rs b/src/thin/mod.rs
index db3dfc4..cbaa118 100644
--- a/src/thin/mod.rs
+++ b/src/thin/mod.rs
@@ -2,6 +2,7 @@ pub mod block_time;
 pub mod check;
 pub mod device_detail;
 pub mod dump;
+pub mod ir;
 pub mod restore;
 pub mod runs;
 pub mod superblock;
diff --git a/src/thin/restore.rs b/src/thin/restore.rs
index 5b9dea4..cab683a 100644
--- a/src/thin/restore.rs
+++ b/src/thin/restore.rs
@@ -16,8 +16,9 @@ use crate::pdata::unpack::Pack;
 use crate::report::*;
 use crate::thin::block_time::*;
 use crate::thin::device_detail::*;
+use crate::thin::ir::{self, MetadataVisitor, Visit};
 use crate::thin::superblock::{self, *};
-use crate::thin::xml::{self, *};
+use crate::thin::xml;
 use crate::write_batcher::*;
 
 //------------------------------------------
@@ -58,7 +59,7 @@ impl std::fmt::Display for MappedSection {
 //------------------------------------------
 
 struct RestoreResult {
-    sb: xml::Superblock,
+    sb: ir::Superblock,
     devices: BTreeMap<u32, (DeviceDetail, u64)>,
     data_sm: Arc<Mutex<dyn SpaceMap>>,
 }
@@ -74,7 +75,7 @@ struct Restorer<'a> {
     current_map: Option<(MappedSection, NodeBuilder<BlockTime>)>,
     current_dev: Option<DeviceDetail>,
 
-    sb: Option<xml::Superblock>,
+    sb: Option<ir::Superblock>,
     devices: BTreeMap<u32, (DeviceDetail, u64)>,
     data_sm: Option<Arc<Mutex<dyn SpaceMap>>>,
 }
@@ -136,7 +137,7 @@ impl<'a> Restorer<'a> {
 }
 
 impl<'a> MetadataVisitor for Restorer<'a> {
-    fn superblock_b(&mut self, sb: &xml::Superblock) -> Result<Visit> {
+    fn superblock_b(&mut self, sb: &ir::Superblock) -> Result<Visit> {
         self.sb = Some(sb.clone());
         self.data_sm = Some(core_sm(sb.nr_data_blocks, u32::MAX));
         self.w.alloc()?;
@@ -160,7 +161,7 @@ impl<'a> MetadataVisitor for Restorer<'a> {
         }
     }
 
-    fn device_b(&mut self, d: &Device) -> Result<Visit> {
+    fn device_b(&mut self, d: &ir::Device) -> Result<Visit> {
         self.report
             .info(&format!("building btree for device {}", d.dev_id));
         self.current_dev = Some(DeviceDetail {
@@ -186,7 +187,7 @@ impl<'a> MetadataVisitor for Restorer<'a> {
         }
     }
 
-    fn map(&mut self, m: &Map) -> Result<Visit> {
+    fn map(&mut self, m: &ir::Map) -> Result<Visit> {
         if let Some((_, builder)) = self.current_map.as_mut() {
             for i in 0..m.len {
                 let bt = BlockTime {
diff --git a/src/thin/xml.rs b/src/thin/xml.rs
index a5c35a9..42bfe0d 100644
--- a/src/thin/xml.rs
+++ b/src/thin/xml.rs
@@ -4,63 +4,11 @@ use std::{io::prelude::*, io::BufReader, io::Write};
 use quick_xml::events::{BytesEnd, BytesStart, Event};
 use quick_xml::{Reader, Writer};
 
+use crate::thin::ir::*;
 use crate::xml::*;
 
 //---------------------------------------
 
-#[derive(Clone)]
-pub struct Superblock {
-    pub uuid: String,
-    pub time: u64,
-    pub transaction: u64,
-    pub flags: Option<u32>,
-    pub version: Option<u32>,
-    pub data_block_size: u32,
-    pub nr_data_blocks: u64,
-    pub metadata_snap: Option<u64>,
-}
-
-#[derive(Clone)]
-pub struct Device {
-    pub dev_id: u32,
-    pub mapped_blocks: u64,
-    pub transaction: u64,
-    pub creation_time: u64,
-    pub snap_time: u64,
-}
-
-#[derive(Clone)]
-pub struct Map {
-    pub thin_begin: u64,
-    pub data_begin: u64,
-    pub time: u32,
-    pub len: u64,
-}
-
-#[derive(Clone)]
-pub enum Visit {
-    Continue,
-    Stop,
-}
-
-pub trait MetadataVisitor {
-    fn superblock_b(&mut self, sb: &Superblock) -> Result<Visit>;
-    fn superblock_e(&mut self) -> Result<Visit>;
-
-    // Defines a shared sub tree.  May only contain a 'map' (no 'ref' allowed).
-    fn def_shared_b(&mut self, name: &str) -> Result<Visit>;
-    fn def_shared_e(&mut self) -> Result<Visit>;
-
-    // A device contains a number of 'map' or 'ref' items.
-    fn device_b(&mut self, d: &Device) -> Result<Visit>;
-    fn device_e(&mut self) -> Result<Visit>;
-
-    fn map(&mut self, m: &Map) -> Result<Visit>;
-    fn ref_shared(&mut self, name: &str) -> Result<Visit>;
-
-    fn eof(&mut self) -> Result<Visit>;
-}
-
 pub struct XmlWriter<W: Write> {
     w: Writer<W>,
 }
@@ -178,7 +126,7 @@ impl<W: Write> MetadataVisitor for XmlWriter<W> {
 
 fn parse_superblock(e: &BytesStart) -> Result<Superblock> {
     let mut uuid: Option<String> = None;
-    let mut time: Option<u64> = None;
+    let mut time: Option<u32> = None;
     let mut transaction: Option<u64> = None;
     let mut flags: Option<u32> = None;
     let mut version: Option<u32> = None;
@@ -190,7 +138,7 @@ fn parse_superblock(e: &BytesStart) -> Result<Superblock> {
         let kv = a.unwrap();
         match kv.key {
             b"uuid" => uuid = Some(string_val(&kv)),
-            b"time" => time = Some(u64_val(&kv)?),
+            b"time" => time = Some(u32_val(&kv)?),
             b"transaction" => transaction = Some(u64_val(&kv)?),
             b"flags" => flags = Some(u32_val(&kv)?),
             b"version" => version = Some(u32_val(&kv)?),
@@ -235,8 +183,8 @@ fn parse_device(e: &BytesStart) -> Result<Device> {
     let mut dev_id: Option<u32> = None;
     let mut mapped_blocks: Option<u64> = None;
     let mut transaction: Option<u64> = None;
-    let mut creation_time: Option<u64> = None;
-    let mut snap_time: Option<u64> = None;
+    let mut creation_time: Option<u32> = None;
+    let mut snap_time: Option<u32> = None;
 
     for a in e.attributes() {
         let kv = a.unwrap();
@@ -244,8 +192,8 @@ fn parse_device(e: &BytesStart) -> Result<Device> {
             b"dev_id" => dev_id = Some(u32_val(&kv)?),
             b"mapped_blocks" => mapped_blocks = Some(u64_val(&kv)?),
             b"transaction" => transaction = Some(u64_val(&kv)?),
-            b"creation_time" => creation_time = Some(u64_val(&kv)?),
-            b"snap_time" => snap_time = Some(u64_val(&kv)?),
+            b"creation_time" => creation_time = Some(u32_val(&kv)?),
+            b"snap_time" => snap_time = Some(u32_val(&kv)?),
             _ => return bad_attr("device", kv.key),
         }
     }
diff --git a/tests/common/cache_xml_generator.rs b/tests/common/cache_xml_generator.rs
index 3621d50..e7df242 100644
--- a/tests/common/cache_xml_generator.rs
+++ b/tests/common/cache_xml_generator.rs
@@ -3,12 +3,13 @@ use rand::prelude::*;
 use std::collections::HashSet;
 use std::fs::OpenOptions;
 use std::path::Path;
+use thinp::cache::ir::{self, MetadataVisitor};
 use thinp::cache::xml;
 
 //------------------------------------------
 
 pub trait XmlGen {
-    fn generate_xml(&mut self, v: &mut dyn xml::MetadataVisitor) -> Result<()>;
+    fn generate_xml(&mut self, v: &mut dyn MetadataVisitor) -> Result<()>;
 }
 
 pub fn write_xml(path: &Path, g: &mut dyn XmlGen) -> Result<()> {
@@ -50,8 +51,8 @@ impl CacheGen {
 }
 
 impl XmlGen for CacheGen {
-    fn generate_xml(&mut self, v: &mut dyn xml::MetadataVisitor) -> Result<()> {
-        v.superblock_b(&xml::Superblock {
+    fn generate_xml(&mut self, v: &mut dyn MetadataVisitor) -> Result<()> {
+        v.superblock_b(&ir::Superblock {
             uuid: "".to_string(),
             block_size: self.block_size,
             nr_cache_blocks: self.nr_cache_blocks,
@@ -77,7 +78,7 @@ impl XmlGen for CacheGen {
 
                 used.insert(oblock);
                 // FIXME: dirty should vary
-                v.mapping(&xml::Map {
+                v.mapping(&ir::Map {
                     cblock: cblocks[n as usize],
                     oblock,
                     dirty: false,
diff --git a/tests/common/thin_xml_generator.rs b/tests/common/thin_xml_generator.rs
index 83084d1..9d56856 100644
--- a/tests/common/thin_xml_generator.rs
+++ b/tests/common/thin_xml_generator.rs
@@ -4,12 +4,13 @@ use std::collections::VecDeque;
 use std::fs::OpenOptions;
 use std::ops::Range;
 use std::path::Path;
+use thinp::thin::ir::{self, MetadataVisitor};
 use thinp::thin::xml;
 
 //------------------------------------------
 
 pub trait XmlGen {
-    fn generate_xml(&mut self, v: &mut dyn xml::MetadataVisitor) -> Result<()>;
+    fn generate_xml(&mut self, v: &mut dyn MetadataVisitor) -> Result<()>;
 }
 
 pub fn write_xml(path: &Path, g: &mut dyn XmlGen) -> Result<()> {
@@ -24,8 +25,8 @@ pub fn write_xml(path: &Path, g: &mut dyn XmlGen) -> Result<()> {
     g.generate_xml(&mut w)
 }
 
-fn common_sb(nr_blocks: u64) -> xml::Superblock {
-    xml::Superblock {
+fn common_sb(nr_blocks: u64) -> ir::Superblock {
+    ir::Superblock {
         uuid: "".to_string(),
         time: 0,
         transaction: 0,
@@ -42,7 +43,7 @@ fn common_sb(nr_blocks: u64) -> xml::Superblock {
 pub struct EmptyPoolS {}
 
 impl XmlGen for EmptyPoolS {
-    fn generate_xml(&mut self, v: &mut dyn xml::MetadataVisitor) -> Result<()> {
+    fn generate_xml(&mut self, v: &mut dyn MetadataVisitor) -> Result<()> {
         v.superblock_b(&common_sb(1024))?;
         v.superblock_e()?;
         Ok(())
@@ -70,16 +71,16 @@ impl SingleThinS {
 }
 
 impl XmlGen for SingleThinS {
-    fn generate_xml(&mut self, v: &mut dyn xml::MetadataVisitor) -> Result<()> {
+    fn generate_xml(&mut self, v: &mut dyn MetadataVisitor) -> Result<()> {
         v.superblock_b(&common_sb(self.old_nr_data_blocks))?;
-        v.device_b(&xml::Device {
+        v.device_b(&ir::Device {
             dev_id: 0,
             mapped_blocks: self.len,
             transaction: 0,
             creation_time: 0,
             snap_time: 0,
         })?;
-        v.map(&xml::Map {
+        v.map(&ir::Map {
             thin_begin: 0,
             data_begin: self.offset,
             time: 0,
@@ -146,7 +147,7 @@ fn mk_runs(thin_id: u32, total_len: u64, run_len: std::ops::Range<u64>) -> Vec<T
 }
 
 impl XmlGen for FragmentedS {
-    fn generate_xml(&mut self, v: &mut dyn xml::MetadataVisitor) -> Result<()> {
+    fn generate_xml(&mut self, v: &mut dyn MetadataVisitor) -> Result<()> {
         // Allocate each thin fully, in runs between 1 and 16.
         let mut runs = Vec::new();
         for thin in 0..self.nr_thins {
@@ -188,7 +189,7 @@ impl XmlGen for FragmentedS {
         // write the xml
         v.superblock_b(&common_sb(self.old_nr_data_blocks))?;
         for thin in 0..self.nr_thins {
-            v.device_b(&xml::Device {
+            v.device_b(&ir::Device {
                 dev_id: thin,
                 mapped_blocks: self.thin_size,
                 transaction: 0,
@@ -201,7 +202,7 @@ impl XmlGen for FragmentedS {
                     continue;
                 }
 
-                v.map(&xml::Map {
+                v.map(&ir::Map {
                     thin_begin: m.thin_begin,
                     data_begin: m.data_begin,
                     time: 0,
@@ -329,8 +330,8 @@ struct ThinDev {
 }
 
 impl ThinDev {
-    fn emit(&self, v: &mut dyn xml::MetadataVisitor) -> Result<()> {
-        v.device_b(&xml::Device {
+    fn emit(&self, v: &mut dyn MetadataVisitor) -> Result<()> {
+        v.device_b(&ir::Device {
             dev_id: self.thin_id,
             mapped_blocks: self.dev_size,
             transaction: 0,
@@ -342,7 +343,7 @@ impl ThinDev {
         for r in &self.runs {
             match r {
                 Run::Mapped { data_begin, len } => {
-                    v.map(&xml::Map {
+                    v.map(&ir::Map {
                         thin_begin: b,
                         data_begin: *data_begin,
                         time: 0,
@@ -522,7 +523,7 @@ impl SnapS {
 }
 
 impl XmlGen for SnapS {
-    fn generate_xml(&mut self, v: &mut dyn xml::MetadataVisitor) -> Result<()> {
+    fn generate_xml(&mut self, v: &mut dyn MetadataVisitor) -> Result<()> {
         let mut allocator = Allocator::new_shuffled(self.old_nr_data_blocks, 64..512);
         let origin = mk_origin(0, self.len, &mut allocator)?;
 
diff --git a/tests/thin_shrink.rs b/tests/thin_shrink.rs
index e796dfd..bbe78d4 100644
--- a/tests/thin_shrink.rs
+++ b/tests/thin_shrink.rs
@@ -6,7 +6,8 @@ use std::io::{Cursor, Read, Seek, SeekFrom, Write};
 use std::path::Path;
 
 use thinp::file_utils;
-use thinp::thin::xml::{self, Visit};
+use thinp::thin::ir::{self, MetadataVisitor, Visit};
+use thinp::thin::xml;
 
 mod common;
 use common::test_dir::*;
@@ -91,8 +92,8 @@ struct ThinXmlVisitor<'a, V: ThinVisitor> {
     thin_id: Option<u32>,
 }
 
-impl<'a, V: ThinVisitor> xml::MetadataVisitor for ThinXmlVisitor<'a, V> {
-    fn superblock_b(&mut self, sb: &xml::Superblock) -> Result<Visit> {
+impl<'a, V: ThinVisitor> MetadataVisitor for ThinXmlVisitor<'a, V> {
+    fn superblock_b(&mut self, sb: &ir::Superblock) -> Result<Visit> {
         self.block_size = Some(sb.data_block_size);
         Ok(Visit::Continue)
     }
@@ -109,7 +110,7 @@ impl<'a, V: ThinVisitor> xml::MetadataVisitor for ThinXmlVisitor<'a, V> {
         todo!();
     }
 
-    fn device_b(&mut self, d: &xml::Device) -> Result<Visit> {
+    fn device_b(&mut self, d: &ir::Device) -> Result<Visit> {
         self.thin_id = Some(d.dev_id);
         Ok(Visit::Continue)
     }
@@ -118,7 +119,7 @@ impl<'a, V: ThinVisitor> xml::MetadataVisitor for ThinXmlVisitor<'a, V> {
         Ok(Visit::Continue)
     }
 
-    fn map(&mut self, m: &xml::Map) -> Result<Visit> {
+    fn map(&mut self, m: &ir::Map) -> Result<Visit> {
         for i in 0..m.len {
             let block = ThinBlock {
                 thin_id: self.thin_id.unwrap(),