From 927f27fd85d310d422cba192ea9aaacd246c8a6f Mon Sep 17 00:00:00 2001
From: Jiang Liu <gerry@linux.alibaba.com>
Date: Thu, 2 Mar 2023 15:05:29 +0800
Subject: [PATCH] rafs: do not include chunk info array in the metadata blob

Now we can reconstruct chunk info from RAFS v6 data blob with embedded
chunk digest, so no need to embed the chunk info array in the metadata
blob anymore, which helps to dramatically reduce size of metadata blob
for big images.

Signed-off-by: Jiang Liu <gerry@linux.alibaba.com>
---
 rafs/src/builder/core/v6.rs | 52 +++++++++++++++++++++----------------
 src/bin/nydus-image/main.rs |  6 ++---
 2 files changed, 33 insertions(+), 25 deletions(-)

diff --git a/rafs/src/builder/core/v6.rs b/rafs/src/builder/core/v6.rs
index a3a984213a0..160aef336e4 100644
--- a/rafs/src/builder/core/v6.rs
+++ b/rafs/src/builder/core/v6.rs
@@ -16,7 +16,7 @@ use storage::device::BlobFeatures;
 
 use super::chunk_dict::DigestWithBlobIndex;
 use super::node::Node;
-use crate::builder::{Bootstrap, BootstrapContext, BuildContext, ConversionType, Tree};
+use crate::builder::{Bootstrap, BootstrapContext, BuildContext, ConversionType, Feature, Tree};
 use crate::metadata::chunk::ChunkWrapper;
 use crate::metadata::layout::v6::{
     align_offset, calculate_nid, new_v6_inode, RafsV6BlobTable, RafsV6Device, RafsV6Dirent,
@@ -40,7 +40,7 @@ impl Node {
         f_bootstrap: &mut dyn RafsIoWrite,
         orig_meta_addr: u64,
         meta_addr: u64,
-        chunk_cache: &mut BTreeMap<DigestWithBlobIndex, Arc<ChunkWrapper>>,
+        chunk_cache: Option<&mut BTreeMap<DigestWithBlobIndex, Arc<ChunkWrapper>>>,
     ) -> Result<()> {
         let xattr_inline_count = self.info.xattrs.count_v6();
         ensure!(
@@ -68,7 +68,9 @@ impl Node {
         if self.is_dir() {
             self.v6_dump_dir(ctx, f_bootstrap, meta_addr, meta_offset, &mut inode)?;
         } else if self.is_reg() {
-            self.v6_dump_file(ctx, f_bootstrap, chunk_cache, &mut inode)?;
+            if let Some(chunk_cache) = chunk_cache {
+                self.v6_dump_file(ctx, f_bootstrap, chunk_cache, &mut inode)?;
+            }
         } else if self.is_symlink() {
             self.v6_dump_symlink(ctx, f_bootstrap, &mut inode)?;
         } else {
@@ -709,7 +711,11 @@ impl Bootstrap {
         // Each layer uses the corresponding chunk in the blob of its own layer.
         // If HashChunkDict is used here, it will cause duplication. The chunks are removed,
         // resulting in incomplete chunk info.
-        let mut chunk_cache = BTreeMap::new();
+        let mut chunk_cache = if ctx.features.is_enabled(Feature::BlobToc) {
+            None
+        } else {
+            Some(BTreeMap::new())
+        };
 
         // Dump bootstrap
         timing_tracer!(
@@ -720,7 +726,7 @@ impl Bootstrap {
                         bootstrap_ctx.writer.as_mut(),
                         orig_meta_addr,
                         meta_addr,
-                        &mut chunk_cache,
+                        chunk_cache.as_mut(),
                     )
                     .context("failed to dump bootstrap")?;
                 }
@@ -751,24 +757,26 @@ impl Bootstrap {
         }
 
         // TODO: get rid of the chunk info array.
-        // Dump chunk info array.
-        let chunk_table_offset = bootstrap_ctx
-            .writer
-            .seek_to_end()
-            .context("failed to seek to bootstrap's end for chunk table")?;
-        let mut chunk_table_size: u64 = 0;
-        for (_, chunk) in chunk_cache.iter() {
-            let chunk_size = chunk
-                .store(bootstrap_ctx.writer.as_mut())
-                .context("failed to dump chunk table")?;
-            chunk_table_size += chunk_size as u64;
+        if let Some(chunk_cache) = chunk_cache.as_ref() {
+            // Dump chunk info array.
+            let chunk_table_offset = bootstrap_ctx
+                .writer
+                .seek_to_end()
+                .context("failed to seek to bootstrap's end for chunk table")?;
+            let mut chunk_table_size: u64 = 0;
+            for (_, chunk) in chunk_cache.iter() {
+                let chunk_size = chunk
+                    .store(bootstrap_ctx.writer.as_mut())
+                    .context("failed to dump chunk table")?;
+                chunk_table_size += chunk_size as u64;
+            }
+            ext_sb.set_chunk_table(chunk_table_offset, chunk_table_size);
+            debug!(
+                "chunk_table offset {} size {}",
+                chunk_table_offset, chunk_table_size
+            );
+            Self::v6_align_to_4k(bootstrap_ctx)?;
         }
-        ext_sb.set_chunk_table(chunk_table_offset, chunk_table_size);
-        debug!(
-            "chunk_table offset {} size {}",
-            chunk_table_offset, chunk_table_size
-        );
-        Self::v6_align_to_4k(bootstrap_ctx)?;
 
         // Prepare device slots.
         let mut pos = bootstrap_ctx
diff --git a/src/bin/nydus-image/main.rs b/src/bin/nydus-image/main.rs
index 4548ad85437..f86fa24d1eb 100644
--- a/src/bin/nydus-image/main.rs
+++ b/src/bin/nydus-image/main.rs
@@ -1077,9 +1077,9 @@ impl Command {
         };
         let config =
             Self::get_configuration(matches).context("failed to get configuration information")?;
-        config
-            .internal
-            .set_blob_accessible(matches.get_one::<String>("config").is_some());
+        let blob_accessible = matches.get_one::<String>("config").is_some()
+            || matches.get_one::<String>("blob-dir").is_some();
+        config.internal.set_blob_accessible(blob_accessible);
         let mut ctx = BuildContext {
             prefetch: Self::get_prefetch(matches)?,
             ..Default::default()