nydus-image: fixed getting the wrong chunk content due to using the w…

…rong blob index

The blob index on the disk where erofs exists starts at 1, but the blob index in BlobInfo starts at 0,
and the blob index on the disk is mistakenly used here instead of blobInfo's index

Signed-off-by: zyfjeff <zyfjeff@linux.alibaba.com>

rafs/src/metadata/direct_v6.rs

@@ -1239,7 +1239,7 @@ impl RafsInode for OndiskInodeWrapper {
                 content_len = std::cmp::min(chunk_size, left);
                 let desc = self.make_chunk_io(c, 0, content_len, user_io);
 
-                if c.blob_index() as u32 != descs.bi_vec[0].blob.blob_index() {
+                if desc.blob.blob_index() as u32 != descs.bi_vec[0].blob.blob_index() {
                     vec.push(descs);
                     descs = BlobIoVec::new();
                 }

rafs/src/metadata/layout/v6.rs

@@ -992,6 +992,9 @@ impl RafsV6InodeChunkAddr {
         }
     }
 
+    /// Note: for erofs, bump id by 1 since device id 0 is bootstrap.
+    /// The index in BlobInfo grows from 0, so when using this method to index the corresponding blob,
+    /// the index always needs to be incremented by 1
     /// Get the blob index of the chunk.
     pub fn blob_index(&self) -> u8 {
         (u16::from_le(self.c_blob_addr_hi) & 0x00ff) as u8