[cache (rust)] Fix bugs in array iteration and text outputs

- Fix array indexing
- Fix panic on empty array
- Remove trailing null characters from the policy name
- Change XML tag naming for backward compatibility

src/cache/check.rs

@@ -90,9 +90,7 @@ mod format1 {
         fn visit(&self, _index: u64, b: ArrayBlock<Mapping>) -> array::Result<()> {
             let mut errs: Vec<ArrayError> = Vec::new();
 
-            for i in 0..b.header.nr_entries as usize {
-                let m = b.values[i];
-
+            for m in b.values.iter() {
                 if let Err(e) = self.check_flags(&m) {
                     errs.push(e);
                 }
@@ -180,12 +178,10 @@ mod format2 {
             let mut inner = self.inner.lock().unwrap();
             let mut errs: Vec<ArrayError> = Vec::new();
 
-            let begin = index as usize * b.header.max_entries as usize;
-            for i in 0..b.header.nr_entries {
-                let m = b.values[i as usize];
-
-                if let Err(e) = self.check_flags(&m, inner.dirty_bits.contains(begin + i as usize))
-                {
+            let cbegin = index as u32 * b.header.max_entries;
+            let cend = cbegin + b.header.nr_entries;
+            for (m, cblock) in b.values.iter().zip(cbegin..cend) {
+                if let Err(e) = self.check_flags(&m, inner.dirty_bits.contains(cblock as usize)) {
                     errs.push(e);
                 }
                 if let Err(e) = self.check_oblock(&m, &mut inner.seen_oblocks) {

src/cache/dump.rs

@@ -47,20 +47,21 @@ mod format1 {
 
     impl<'a> ArrayVisitor<Mapping> for MappingEmitter<'a> {
         fn visit(&self, index: u64, b: ArrayBlock<Mapping>) -> array::Result<()> {
-            for i in 0..b.header.nr_entries as usize {
-                let map = b.values[i];
+            let cbegin = index as u32 * b.header.max_entries;
+            let cend = cbegin + b.header.nr_entries;
+            for (map, cblock) in b.values.iter().zip(cbegin..cend) {
                 if !map.is_valid() {
                     continue;
                 }
 
                 let m = xml::Map {
-                    cblock: index as u32,
+                    cblock,
                     oblock: map.oblock,
                     dirty: map.is_dirty(),
                 };
 
                 let mut inner = self.inner.lock().unwrap();
-                inner.valid_mappings.set(index as usize, true);
+                inner.valid_mappings.set(cblock as usize, true);
                 inner
                     .visitor
                     .mapping(&m)
@@ -100,9 +101,7 @@ mod format2 {
     impl ArrayVisitor<u64> for DirtyVisitor {
         fn visit(&self, index: u64, b: ArrayBlock<u64>) -> array::Result<()> {
             let mut pos = (index as usize * (b.header.max_entries as usize)) << 6;
-            for i in 0..b.header.nr_entries as usize {
-                let bits = b.values[i];
-
+            for bits in b.values.iter() {
                 for bi in 0..64u64 {
                     if pos >= self.nr_entries {
                         break;
@@ -152,22 +151,22 @@ mod format2 {
 
     impl<'a> ArrayVisitor<Mapping> for MappingEmitter<'a> {
         fn visit(&self, index: u64, b: ArrayBlock<Mapping>) -> array::Result<()> {
-            for i in 0..b.header.nr_entries as usize {
-                let map = b.values[i];
-
+            let cbegin = index as u32 * b.header.max_entries;
+            let cend = cbegin + b.header.nr_entries;
+            for (map, cblock) in b.values.iter().zip(cbegin..cend) {
                 if !map.is_valid() {
                     continue;
                 }
 
                 let mut inner = self.inner.lock().unwrap();
-                let dirty = inner.dirty_bits.contains(index as usize);
+                let dirty = inner.dirty_bits.contains(cblock as usize);
                 let m = xml::Map {
-                    cblock: index as u32,
+                    cblock,
                     oblock: map.oblock,
                     dirty,
                 };
 
-                inner.valid_mappings.set(index as usize, true);
+                inner.valid_mappings.set(cblock as usize, true);
                 inner
                     .visitor
                     .mapping(&m)
@@ -196,13 +195,13 @@ impl<'a> HintEmitter<'a> {
 
 impl<'a> ArrayVisitor<Hint> for HintEmitter<'a> {
     fn visit(&self, index: u64, b: ArrayBlock<Hint>) -> array::Result<()> {
-        let mut cblock = index as u32 * b.header.max_entries;
-        for i in 0..b.header.nr_entries as usize {
+        let cbegin = index as u32 * b.header.max_entries;
+        let cend = cbegin + b.header.nr_entries;
+        for (hint, cblock) in b.values.iter().zip(cbegin..cend) {
             if !self.valid_mappings.contains(cblock as usize) {
                 continue;
             }
 
-            let hint = b.values[i];
             let h = xml::Hint {
                 cblock,
                 data: hint.hint.to_vec(),
@@ -213,8 +212,6 @@ impl<'a> ArrayVisitor<Hint> for HintEmitter<'a> {
                 .unwrap()
                 .hint(&h)
                 .map_err(|e| array::value_err(format!("{}", e)))?;
-
-            cblock += 1;
         }
 
         Ok(())
@@ -254,7 +251,7 @@ fn dump_metadata(ctx: &Context, sb: &Superblock, _repair: bool) -> anyhow::Resul
         uuid: "".to_string(),
         block_size: sb.data_block_size,
         nr_cache_blocks: sb.cache_blocks,
-        policy: std::str::from_utf8(&sb.policy_name[..])?.to_string(),
+        policy: std::str::from_utf8(&sb.policy_name)?.to_string(),
         hint_width: sb.policy_hint_size,
     };
     out.superblock_b(&xml_sb)?;

src/cache/superblock.rs

@@ -104,7 +104,7 @@ fn unpack(data: &[u8]) -> IResult<&[u8], Superblock> {
             },
             block,
             version,
-            policy_name: policy_name.to_vec(),
+            policy_name: policy_name.splitn(2, |c| *c == 0).next().unwrap().to_vec(),
             policy_version: vec![vsn_major, vsn_minor, vsn_patch],
             policy_hint_size,
             metadata_sm_root: metadata_sm_root.to_vec(),

src/cache/xml.rs

@@ -119,7 +119,7 @@ impl<W: Write> MetadataVisitor for XmlWriter<W> {
     }
 
     fn mapping(&mut self, m: &Map) -> Result<Visit> {
-        let tag = b"map";
+        let tag = b"mapping";
         let mut elem = BytesStart::owned(tag.to_vec(), tag.len());
         elem.push_attribute(mk_attr(b"cache_block", m.cblock));
         elem.push_attribute(mk_attr(b"origin_block", m.oblock));

src/pdata/array_walker.rs

@@ -53,7 +53,9 @@ impl<'a, V: Unpack + Copy> NodeVisitor<u64> for BlockValueVisitor<'a, V> {
         keys: &[u64],
         values: &[u64],
     ) -> btree::Result<()> {
-        let mut path = path.to_vec();
+        if keys.is_empty() {
+            return Ok(());
+        }
 
         // The ordering of array indices had been verified in unpack_node(),
         // thus checking the upper bound implies key continuity among siblings.
@@ -86,6 +88,7 @@ impl<'a, V: Unpack + Copy> NodeVisitor<u64> for BlockValueVisitor<'a, V> {
                             array_errs.push(array::io_err(&path, values[i]).index_context(keys[i]));
                         }
                         Ok(b) => {
+                            let mut path = path.to_vec();
                             path.push(b.loc);
                             match unpack_array_block::<V>(&path, b.get_data()) {
                                 Ok(array_block) => {

src/pdata/bitset.rs

@@ -58,10 +58,9 @@ impl ArrayVisitor<u64> for BitsetVisitor {
             )));
         }
 
-        for i in 0..b.header.nr_entries as usize {
+        for bits in b.values.iter() {
             let end: usize = std::cmp::min(begin + 64, self.nr_bits as usize);
             let mut mask = 1;
-            let bits = b.values[i];
 
             for bi in begin..end {
                 self.bits.lock().unwrap().set(bi, bits & mask != 0);