nydusd: solving the mismatch between nydus chunk amplification and dy…

…namic dedup.

The mismatch between dynamic dedup and nydus' chunk amplification can
result in a larger cache size after dedup than without dedup. Because
chunk amplification can cause reused chunks to be pulled multiple
times, resulting in a larger cache size after dedup is enabled than when
dedup is not enabled.

To address this issue, a dedup_bitmap was introduced. When initializing
rafs, dedup_bitmap is generated based on the chunk information in blob.
The determination of whether a chunk in a blob is ready requires both
the chunk map and deduplication bitmap to make a joint decision.

Signed-off-by: xwb1136021767 <[email protected]>

storage/src/device.rs

@@ -1181,32 +1181,22 @@ impl BlobDevice {
     /// Create new blob device instance.
     pub fn new(config: &Arc<ConfigV2>, blob_infos: &[Arc<BlobInfo>]) -> io::Result<BlobDevice> {
         let mut blobs = Vec::with_capacity(blob_infos.len());
-        let dedup_config = config.get_dedup_config()?;
-        let mut is_dedup = dedup_config.get_enable();
-        let cas_mgr = match is_dedup {
-            true => {
-                let db_path = dedup_config.get_work_dir()?;
-                match CasMgr::new(db_path) {
-                    Ok(cas_mgr) => Some(cas_mgr),
-                    Err(_) => {
-                        is_dedup = false;
-                        None
-                    }
-                }
-            }
-            false => None,
-        };
+        let dedup_config = config.get_dedup_config().ok();
+        let cas_mgr = dedup_config
+            .as_ref()
+            .filter(|config| config.get_enable() && config.get_work_dir().is_ok())
+            .and_then(|config| CasMgr::new(config.get_work_dir().unwrap()).ok());
 
         for blob_info in blob_infos.iter() {
-            let blob = match is_dedup {
-                true => {
-                    let new_blob_config = Self::get_new_blob_config(&cas_mgr, blob_info, config)?;
-                    BLOB_FACTORY.new_blob_cache(&new_blob_config, blob_info)?
-                }
-                false => BLOB_FACTORY.new_blob_cache(config, blob_info)?,
+            let blob = if let Some(cas_mgr) = &cas_mgr {
+                Self::get_new_blob_config(cas_mgr, blob_info, config).and_then(|new_blob_config| {
+                    BLOB_FACTORY.new_blob_cache(&new_blob_config, blob_info)
+                })
+            } else {
+                BLOB_FACTORY.new_blob_cache(config, blob_info)
             };
 
-            blobs.push(blob);
+            blobs.push(blob.unwrap());
         }
 
         Ok(BlobDevice {
@@ -1216,11 +1206,10 @@ impl BlobDevice {
     }
 
     fn get_new_blob_config(
-        cas_mgr: &Option<CasMgr>,
+        cas_mgr: &CasMgr,
         blob_info: &Arc<BlobInfo>,
         config: &Arc<ConfigV2>,
     ) -> io::Result<Arc<ConfigV2>> {
-        let cas_mgr = cas_mgr.as_ref().unwrap();
         let blob_id = blob_info.blob_id();
         let blob_backend = Self::get_blob_backend_config(cas_mgr, &blob_id)?;
         let mut blob_config = config.deref().clone();