builder: align file dump order with prefetch list, fix #1488

1. The dump order for prefetch files does not match the order specified in prefetch list,
so let's fix it.
2. The construction of `Prefetch` is slow due to inefficient matching of prefetch patterns,
By adopting a more efficient data structure, this process has been accelerated.
3. Unit tests for prefetch are added.

Signed-off-by: Wenhao Ren <wenhaoren@mail.dlut.edu.cn>

builder/src/core/blob.rs

@@ -16,7 +16,7 @@ use sha2::digest::Digest;
 use super::layout::BlobLayout;
 use super::node::Node;
 use crate::core::context::Artifact;
-use crate::{BlobContext, BlobManager, BuildContext, ConversionType, Feature, Tree};
+use crate::{BlobContext, BlobManager, BuildContext, ConversionType, Feature};
 
 /// Generator for RAFS data blob.
 pub(crate) struct Blob {}
@@ -25,15 +25,13 @@ impl Blob {
     /// Dump blob file and generate chunks
     pub(crate) fn dump(
         ctx: &BuildContext,
-        tree: &Tree,
         blob_mgr: &mut BlobManager,
         blob_writer: &mut dyn Artifact,
     ) -> Result<()> {
         match ctx.conversion_type {
             ConversionType::DirectoryToRafs => {
                 let mut chunk_data_buf = vec![0u8; RAFS_MAX_CHUNK_SIZE as usize];
-                let (inodes, prefetch_entries) =
-                    BlobLayout::layout_blob_simple(&ctx.prefetch, tree)?;
+                let (inodes, prefetch_entries) = BlobLayout::layout_blob_simple(&ctx.prefetch)?;
                 for (idx, node) in inodes.iter().enumerate() {
                     let mut node = node.lock().unwrap();
                     let size = node

builder/src/core/bootstrap.rs

@@ -37,8 +37,7 @@ impl Bootstrap {
         assert_eq!(index, RAFS_V5_ROOT_INODE);
         root_node.index = index;
         root_node.inode.set_ino(index);
-        ctx.prefetch
-            .insert_if_need(&self.tree.node, root_node.deref());
+        ctx.prefetch.insert(&self.tree.node, root_node.deref());
         bootstrap_ctx.inode_map.insert(
             (
                 root_node.layer_idx,
@@ -160,7 +159,7 @@ impl Bootstrap {
             if !child_node.is_dir() && ctx.fs_version.is_v6() {
                 child_node.v6_set_offset(bootstrap_ctx, v6_hardlink_offset, block_size)?;
             }
-            ctx.prefetch.insert_if_need(&child.node, child_node.deref());
+            ctx.prefetch.insert(&child.node, child_node.deref());
             if child_node.is_dir() {
                 dirs.push(child);
             }

builder/src/core/layout.rs

@@ -6,37 +6,26 @@ use anyhow::Result;
 use std::ops::Deref;
 
 use super::node::Node;
-use crate::{Overlay, Prefetch, Tree, TreeNode};
+use crate::{Overlay, Prefetch, TreeNode};
 
 #[derive(Clone)]
 pub struct BlobLayout {}
 
 impl BlobLayout {
-    pub fn layout_blob_simple(prefetch: &Prefetch, tree: &Tree) -> Result<(Vec<TreeNode>, usize)> {
-        let mut inodes = Vec::with_capacity(10000);
-
-        // Put all prefetch inodes at the head
-        // NOTE: Don't try to sort readahead files by their sizes,  thus to keep files
-        // belonging to the same directory arranged in adjacent in blob file. Together with
-        // BFS style collecting descendants inodes, it will have a higher merging possibility.
-        // Later, we might write chunks of data one by one according to inode number order.
-        let prefetches = prefetch.get_file_nodes();
-        for n in prefetches {
-            let node = n.lock().unwrap();
-            if Self::should_dump_node(node.deref()) {
-                inodes.push(n.clone());
-            }
-        }
+    pub fn layout_blob_simple(prefetch: &Prefetch) -> Result<(Vec<TreeNode>, usize)> {
+        let (pre, non_pre) = prefetch.get_file_nodes();
+        let mut inodes: Vec<TreeNode> = pre
+            .into_iter()
+            .filter(|x| Self::should_dump_node(x.lock().unwrap().deref()))
+            .collect();
+        let mut non_prefetch_inodes: Vec<TreeNode> = non_pre
+            .into_iter()
+            .filter(|x| Self::should_dump_node(x.lock().unwrap().deref()))
+            .collect();
+
         let prefetch_entries = inodes.len();
 
-        tree.walk_bfs(true, &mut |n| -> Result<()> {
-            let node = n.lock_node();
-            // Ignore lower layer node when dump blob
-            if !prefetch.contains(node.deref()) && Self::should_dump_node(node.deref()) {
-                inodes.push(n.node.clone());
-            }
-            Ok(())
-        })?;
+        inodes.append(&mut non_prefetch_inodes);
 
         Ok((inodes, prefetch_entries))
     }
@@ -46,3 +35,28 @@ impl BlobLayout {
         node.overlay == Overlay::UpperAddition || node.overlay == Overlay::UpperModification
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::{core::node::NodeInfo, Tree};
+    use nydus_rafs::metadata::{inode::InodeWrapper, RafsVersion};
+
+    #[test]
+    fn test_layout_blob_simple() {
+        let mut inode = InodeWrapper::new(RafsVersion::V6);
+        inode.set_mode(0o755 | libc::S_IFREG as u32);
+        inode.set_size(1);
+        let mut node1 = Node::new(inode.clone(), NodeInfo::default(), 1);
+        node1.overlay = Overlay::UpperAddition;
+
+        let tree = Tree::new(node1);
+
+        let mut prefetch = Prefetch::default();
+        prefetch.insert(&tree.node, tree.node.lock().unwrap().deref());
+
+        let (inodes, prefetch_entries) = BlobLayout::layout_blob_simple(&prefetch).unwrap();
+        assert_eq!(inodes.len(), 1);
+        assert_eq!(prefetch_entries, 0);
+    }
+}

builder/src/core/prefetch.rs

@@ -3,7 +3,6 @@
 //
 // SPDX-License-Identifier: Apache-2.0
 
-use std::collections::BTreeMap;
 use std::path::PathBuf;
 use std::str::FromStr;
 
@@ -73,7 +72,7 @@ fn get_patterns() -> Result<IndexMap<PathBuf, Option<TreeNode>>> {
 fn generate_patterns(input: Vec<String>) -> Result<IndexMap<PathBuf, Option<TreeNode>>> {
     let mut patterns = IndexMap::new();
 
-    for (idx, file) in input.iter().enumerate() {
+    for file in &input {
         let file_trimmed: PathBuf = file.trim().into();
         // Sanity check for the list format.
         if !file_trimmed.is_absolute() {
@@ -84,13 +83,21 @@ fn generate_patterns(input: Vec<String>) -> Result<IndexMap<PathBuf, Option<Tree
             continue;
         }
 
-        let mut skip = false;
-        for prefix in input.iter().take(idx) {
-            if file_trimmed.starts_with(prefix) {
+        let mut current_path = file_trimmed.clone();
+        let mut skip = patterns.contains_key(&current_path);
+        while !skip && current_path.pop() {
+            if patterns.contains_key(&current_path) {
                 skip = true;
+                break;
             }
         }
-        if !skip {
+
+        if skip {
+            warn!(
+                "prefetch pattern {} is covered by previous pattern and thus omitted",
+                file
+            );
+        } else {
             debug!(
                 "prefetch pattern: {}, trimmed file name {:?}",
                 file, file_trimmed
@@ -114,8 +121,16 @@ pub struct Prefetch {
     patterns: IndexMap<PathBuf, Option<TreeNode>>,
 
     // File list to help optimizing layout of data blobs.
-    // Files from this list may be put at the head of data blob for better prefetch performance.
-    files: BTreeMap<PathBuf, TreeNode>,
+    // Files from this list may be put at the head of data blob for better prefetch performance,
+    // The index of matched prefetch pattern is stored in `usize`,
+    // which will help to sort the prefetch files in the final layout.
+    // It only stores regular files.
+    files_prefetch: Vec<(TreeNode, usize)>,
+
+    // It stores all non-prefetch files that is not stored in `prefetch_files`,
+    // including regular files, dirs, symlinks, etc.,
+    // with the same order of BFS traversal of file tree.
+    files_non_prefetch: Vec<TreeNode>,
 }
 
 impl Prefetch {
@@ -131,50 +146,63 @@ impl Prefetch {
             policy,
             disabled: false,
             patterns,
-            files: BTreeMap::new(),
+            files_prefetch: Vec::with_capacity(10000),
+            files_non_prefetch: Vec::with_capacity(10000),
         })
     }
 
-    /// Insert node into the prefetch list if it matches prefetch rules.
-    pub fn insert_if_need(&mut self, obj: &TreeNode, node: &Node) {
+    /// Insert node into the prefetch Vector if it matches prefetch rules,
+    /// while recording the index of matched prefetch pattern,
+    /// or insert it into non-prefetch Vector.
+    pub fn insert(&mut self, obj: &TreeNode, node: &Node) {
         // Newly created root inode of this rafs has zero size
         if self.policy == PrefetchPolicy::None
             || self.disabled
             || (node.inode.is_reg() && node.inode.size() == 0)
         {
+            self.files_non_prefetch.push(obj.clone());
             return;
         }
 
-        let path = node.target();
-        for (f, v) in self.patterns.iter_mut() {
-            // As path is canonicalized, it should be reliable.
-            if path == f {
-                if self.policy == PrefetchPolicy::Fs {
+        let mut path = node.target().clone();
+        let mut exact_match = true;
+        loop {
+            if let Some((idx, _, v)) = self.patterns.get_full_mut(&path) {
+                if exact_match {
                     *v = Some(obj.clone());
                 }
                 if node.is_reg() {
-                    self.files.insert(path.clone(), obj.clone());
+                    self.files_prefetch.push((obj.clone(), idx));
+                } else {
+                    self.files_non_prefetch.push(obj.clone());
                 }
-            } else if path.starts_with(f) && node.is_reg() {
-                self.files.insert(path.clone(), obj.clone());
+                return;
             }
+            // If no exact match, try to match parent dir until root.
+            if !path.pop() {
+                self.files_non_prefetch.push(obj.clone());
+                return;
+            }
+            exact_match = false;
         }
     }
 
-    /// Check whether the node is in the prefetch list.
-    pub fn contains(&self, node: &Node) -> bool {
-        self.files.contains_key(node.target())
-    }
+    /// Get node Vector of files in the prefetch list and non-prefetch list.
+    /// The order of prefetch files is the same as the order of prefetch patterns.
+    /// The order of non-prefetch files is the same as the order of BFS traversal of file tree.
+    pub fn get_file_nodes(&self) -> (Vec<TreeNode>, Vec<TreeNode>) {
+        let mut p_files = self.files_prefetch.clone();
+        p_files.sort_by_key(|k| k.1);
 
-    /// Get node index array of files in the prefetch list.
-    pub fn get_file_nodes(&self) -> Vec<TreeNode> {
-        self.files.values().cloned().collect()
+        let p_files = p_files.into_iter().map(|(s, _)| s).collect();
+
+        (p_files, self.files_non_prefetch.clone())
     }
 
-    /// Get number of prefetch rules.
+    /// Get the number of ``valid`` prefetch rules.
     pub fn fs_prefetch_rule_count(&self) -> u32 {
         if self.policy == PrefetchPolicy::Fs {
-            self.patterns.values().len() as u32
+            self.patterns.values().filter(|v| v.is_some()).count() as u32
         } else {
             0
         }
@@ -231,13 +259,18 @@ impl Prefetch {
     /// Reset to initialization state.
     pub fn clear(&mut self) {
         self.disabled = false;
-        self.files.clear();
+        self.patterns.clear();
+        self.files_prefetch.clear();
+        self.files_non_prefetch.clear();
     }
 }
 
 #[cfg(test)]
 mod tests {
     use super::*;
+    use crate::core::node::NodeInfo;
+    use nydus_rafs::metadata::{inode::InodeWrapper, RafsVersion};
+    use std::sync::Mutex;
 
     #[test]
     fn test_generate_pattern() {
@@ -273,4 +306,86 @@ mod tests {
         PrefetchPolicy::from_str("").unwrap_err();
         PrefetchPolicy::from_str("invalid").unwrap_err();
     }
+
+    #[test]
+    fn test_prefetch() {
+        let input = vec![
+            "/a/b".to_string(),
+            "/f".to_string(),
+            "/h/i".to_string(),
+            "/k".to_string(),
+        ];
+        let patterns = generate_patterns(input).unwrap();
+        let mut prefetch = Prefetch {
+            policy: PrefetchPolicy::Fs,
+            disabled: false,
+            patterns,
+            files_prefetch: Vec::with_capacity(10),
+            files_non_prefetch: Vec::with_capacity(10),
+        };
+        let mut inode = InodeWrapper::new(RafsVersion::V6);
+        inode.set_mode(0o755 | libc::S_IFREG as u32);
+        inode.set_size(1);
+
+        let info = NodeInfo::default();
+
+        let mut info1 = info.clone();
+        info1.target = PathBuf::from("/f");
+        let node1 = Node::new(inode.clone(), info1, 1);
+        let node1 = TreeNode::new(Mutex::from(node1));
+        prefetch.insert(&node1, &node1.lock().unwrap());
+
+        let inode2 = inode.clone();
+        let mut info2 = info.clone();
+        info2.target = PathBuf::from("/a/b");
+        let node2 = Node::new(inode2, info2, 1);
+        let node2 = TreeNode::new(Mutex::from(node2));
+        prefetch.insert(&node2, &node2.lock().unwrap());
+
+        let inode3 = inode.clone();
+        let mut info3 = info.clone();
+        info3.target = PathBuf::from("/h/i/j");
+        let node3 = Node::new(inode3, info3, 1);
+        let node3 = TreeNode::new(Mutex::from(node3));
+        prefetch.insert(&node3, &node3.lock().unwrap());
+
+        let inode4 = inode.clone();
+        let mut info4 = info.clone();
+        info4.target = PathBuf::from("/z");
+        let node4 = Node::new(inode4, info4, 1);
+        let node4 = TreeNode::new(Mutex::from(node4));
+        prefetch.insert(&node4, &node4.lock().unwrap());
+
+        let inode5 = inode.clone();
+        inode.set_mode(0o755 | libc::S_IFDIR as u32);
+        inode.set_size(0);
+        let mut info5 = info;
+        info5.target = PathBuf::from("/a/b/d");
+        let node5 = Node::new(inode5, info5, 1);
+        let node5 = TreeNode::new(Mutex::from(node5));
+        prefetch.insert(&node5, &node5.lock().unwrap());
+
+        // node1, node2
+        assert_eq!(prefetch.fs_prefetch_rule_count(), 2);
+
+        let (pre, non_pre) = prefetch.get_file_nodes();
+        assert_eq!(pre.len(), 4);
+        assert_eq!(non_pre.len(), 1);
+        let pre_str: Vec<String> = pre
+            .iter()
+            .map(|n| n.lock().unwrap().target().to_str().unwrap().to_owned())
+            .collect();
+        assert_eq!(pre_str, vec!["/a/b", "/a/b/d", "/f", "/h/i/j"]);
+        let non_pre_str: Vec<String> = non_pre
+            .iter()
+            .map(|n| n.lock().unwrap().target().to_str().unwrap().to_owned())
+            .collect();
+        assert_eq!(non_pre_str, vec!["/z"]);
+
+        prefetch.clear();
+        assert_eq!(prefetch.fs_prefetch_rule_count(), 0);
+        let (pre, non_pre) = prefetch.get_file_nodes();
+        assert_eq!(pre.len(), 0);
+        assert_eq!(non_pre.len(), 0);
+    }
 }

builder/src/directory.rs

@@ -148,7 +148,7 @@ impl Builder for DirectoryBuilder {
 
         // Dump blob file
         timing_tracer!(
-            { Blob::dump(ctx, &bootstrap.tree, blob_mgr, blob_writer.as_mut(),) },
+            { Blob::dump(ctx, blob_mgr, blob_writer.as_mut()) },
             "dump_blob"
         )?;
 

builder/src/stargz.rs

@@ -860,7 +860,7 @@ impl Builder for StargzBuilder {
 
         // Dump blob file
         timing_tracer!(
-            { Blob::dump(ctx, &bootstrap.tree, blob_mgr, blob_writer.as_mut()) },
+            { Blob::dump(ctx, blob_mgr, blob_writer.as_mut()) },
             "dump_blob"
         )?;