feat: reuse blob cache of old version

    Nydus2.2 has same format for blob cache and bitmap on disk. However,
    2.2 nydusd not use blob cache of 1.6 nydusd. This pr counts ready
    chunk number for both 1.6 and 2.2, instead of thinking it as not filled
    at all.

Signed-off-by: 泰友 <[email protected]>

Author: 泰友

storage/src/cache/filecache/mod.rs

@@ -25,7 +25,7 @@ use crate::cache::{BlobCache, BlobCacheMgr};
 use crate::device::{BlobFeatures, BlobInfo};
 
 pub const BLOB_RAW_FILE_SUFFIX: &str = ".blob.raw";
-pub const BLOB_DATA_FILE_SUFFIX: &str = ".blob.data";
+pub const BLOB_DATA_FILE_SUFFIX: &str = "";
 
 /// An implementation of [BlobCacheMgr](../trait.BlobCacheMgr.html) to improve performance by
 /// caching uncompressed blob with local storage.

storage/src/cache/state/persist_map.rs

@@ -111,36 +111,33 @@ impl PersistMap {
         }
 
         let header = filemap.get_mut::<Header>(0)?;
-        let mut not_ready_count = chunk_count;
-        if header.version >= 1 {
-            if header.magic2 != MAGIC2 {
-                return Err(einval!(format!(
-                    "invalid blob chunk_map file header: {:?}",
-                    filename
-                )));
+        if header.version >= 1 && header.magic2 != MAGIC2 {
+            return Err(einval!(format!(
+                "invalid blob chunk_map file header: {:?}",
+                filename
+            )));
+        }
+        let not_ready_count = if new_content {
+            chunk_count
+        } else if header.version >= 1 && header.all_ready == MAGIC_ALL_READY {
+            0
+        } else {
+            let mut ready_count = 0;
+            for idx in HEADER_SIZE..expected_size as usize {
+                let current = filemap.get_ref::<AtomicU8>(idx)?;
+                let val = current.load(Ordering::Acquire);
+                ready_count += val.count_ones() as u32;
             }
-            if header.all_ready == MAGIC_ALL_READY {
-                not_ready_count = 0;
-            } else if new_content {
-                not_ready_count = chunk_count;
-            } else {
-                let mut ready_count = 0;
-                for idx in HEADER_SIZE..expected_size as usize {
-                    let current = filemap.get_ref::<AtomicU8>(idx)?;
-                    let val = current.load(Ordering::Acquire);
-                    ready_count += val.count_ones() as u32;
-                }
 
-                if ready_count >= chunk_count {
-                    let header = filemap.get_mut::<Header>(0)?;
-                    header.all_ready = MAGIC_ALL_READY;
-                    let _ = file.sync_all();
-                    not_ready_count = 0;
-                } else {
-                    not_ready_count = chunk_count - ready_count;
-                }
+            if ready_count >= chunk_count {
+                let header = filemap.get_mut::<Header>(0)?;
+                header.all_ready = MAGIC_ALL_READY;
+                let _ = file.sync_all();
+                0
+            } else {
+                chunk_count - ready_count
             }
-        }
+        };
 
         readahead(file.as_raw_fd(), 0, expected_size);
         if !persist {