rafs: enhance RAFS FUSE implementation to support TARFS

Enhance RAFS FUSE implementation to support RAFS filesystms in
TARFS mode.

Signed-off-by: Jiang Liu <gerry@linux.alibaba.com>

rafs/src/fs.rs

@@ -39,7 +39,7 @@ use nydus_utils::{
 };
 
 use crate::metadata::{
-    Inode, RafsInode, RafsInodeWalkAction, RafsSuper, RafsSuperFlags, RafsSuperMeta, DOT, DOTDOT,
+    Inode, RafsInode, RafsInodeWalkAction, RafsSuper, RafsSuperMeta, DOT, DOTDOT,
 };
 use crate::{RafsError, RafsIoReader, RafsResult};
 
@@ -616,10 +616,6 @@ impl FileSystem for Rafs {
         }
 
         let real_size = cmp::min(size as u64, inode_size - offset);
-        if self.sb.meta.flags.contains(RafsSuperFlags::TARTFS_MODE) {
-            return Err(enosys!("rafs: `TARFS` mode is not supported by FUSE yet"));
-        }
-
         let mut result = 0;
         let mut descs = inode.alloc_bio_vecs(&self.device, offset, real_size as usize, true)?;
         assert!(!descs.is_empty() && !descs[0].is_empty());

rafs/src/metadata/direct_v6.rs

@@ -40,8 +40,8 @@ use crate::metadata::layout::v5::RafsV5ChunkInfo;
 use crate::metadata::layout::v6::{
     rafsv6_load_blob_extra_info, recover_namespace, RafsV6BlobTable, RafsV6Dirent,
     RafsV6InodeChunkAddr, RafsV6InodeCompact, RafsV6InodeExtended, RafsV6OndiskInode,
-    RafsV6XattrEntry, RafsV6XattrIbodyHeader, EROFS_BLOCK_SIZE_4096, EROFS_BLOCK_SIZE_512,
-    EROFS_INODE_CHUNK_BASED, EROFS_INODE_FLAT_INLINE, EROFS_INODE_FLAT_PLAIN,
+    RafsV6XattrEntry, RafsV6XattrIbodyHeader, EROFS_BLOCK_BITS_9, EROFS_BLOCK_SIZE_4096,
+    EROFS_BLOCK_SIZE_512, EROFS_INODE_CHUNK_BASED, EROFS_INODE_FLAT_INLINE, EROFS_INODE_FLAT_PLAIN,
     EROFS_INODE_SLOT_SIZE, EROFS_I_DATALAYOUT_BITS, EROFS_I_VERSION_BIT, EROFS_I_VERSION_BITS,
 };
 use crate::metadata::layout::{bytes_to_os_str, MetaRange, XattrName, XattrValue};
@@ -525,6 +525,7 @@ impl OndiskInodeWrapper {
         i.mode() as u32 & libc::S_IFMT as u32
     }
 
+    #[allow(clippy::too-many-arguments)]
     fn make_chunk_io(
         &self,
         state: &Guard<Arc<DirectMappingState>>,
@@ -533,6 +534,8 @@ impl OndiskInodeWrapper {
         content_offset: u32,
         content_len: u32,
         user_io: bool,
+        is_tarfs_mode: bool,
+        is_tail: bool,
     ) -> Option<BlobIoDesc> {
         let blob_index = chunk_addr.blob_index();
         let chunk_index = chunk_addr.blob_ci_index();
@@ -545,9 +548,29 @@ impl OndiskInodeWrapper {
                 );
                 None
             }
-            Ok(blob) => device
-                .create_io_chunk(blob.blob_index(), chunk_index)
-                .map(|v| BlobIoDesc::new(blob, v, content_offset, content_len, user_io)),
+            Ok(blob) => {
+                if is_tarfs_mode {
+                    let offset = (chunk_addr.block_addr() as u64) << EROFS_BLOCK_BITS_9;
+                    let size = if is_tail {
+                        (self.size() % self.chunk_size() as u64) as u32
+                    } else {
+                        self.chunk_size()
+                    };
+                    let chunk = PlainChunkInfoV6::new(blob_index, chunk_index, offset, size);
+                    let chunk = Arc::new(chunk) as Arc<dyn BlobChunkInfo>;
+                    Some(BlobIoDesc::new(
+                        blob,
+                        chunk.into(),
+                        content_offset,
+                        content_len,
+                        user_io,
+                    ))
+                } else {
+                    device
+                        .create_io_chunk(blob.blob_index(), chunk_index)
+                        .map(|v| BlobIoDesc::new(blob, v, content_offset, content_len, user_io))
+                }
+            }
         }
     }
 
@@ -777,6 +800,9 @@ impl RafsInode for OndiskInodeWrapper {
             return Ok(vec);
         }
 
+        let mut curr_chunk_index = head_chunk_index as u32;
+        let tail_chunk_index = self.get_chunk_count() - 1;
+        let is_tarfs_mode = state.is_tarfs();
         let content_offset = (offset % chunk_size as u64) as u32;
         let mut left = std::cmp::min(self.size() - offset, size as u64) as u32;
         let mut content_len = std::cmp::min(chunk_size - content_offset, left);
@@ -788,6 +814,8 @@ impl RafsInode for OndiskInodeWrapper {
                 content_offset,
                 content_len,
                 user_io,
+                is_tarfs_mode,
+                curr_chunk_index == tail_chunk_index,
             )
             .ok_or_else(|| einval!("failed to get chunk information"))?;
 
@@ -797,9 +825,19 @@ impl RafsInode for OndiskInodeWrapper {
         if left != 0 {
             // Handle the rest of chunks since they shares the same content length = 0.
             for c in chunks.iter().skip(1) {
+                curr_chunk_index += 1;
                 content_len = std::cmp::min(chunk_size, left);
                 let desc = self
-                    .make_chunk_io(&state, device, c, 0, content_len, user_io)
+                    .make_chunk_io(
+                        &state,
+                        device,
+                        c,
+                        0,
+                        content_len,
+                        user_io,
+                        is_tarfs_mode,
+                        curr_chunk_index == tail_chunk_index,
+                    )
                     .ok_or_else(|| einval!("failed to get chunk information"))?;
                 if desc.blob.blob_index() != descs.blob_index() {
                     vec.push(descs);
@@ -1286,7 +1324,7 @@ impl RafsInodeExt for OndiskInodeWrapper {
         } else if state.is_tarfs() {
             let blob_index = chunk_addr.blob_index();
             let chunk_index = chunk_addr.blob_ci_index();
-            let offset = (chunk_addr.block_addr() as u64) << 9;
+            let offset = (chunk_addr.block_addr() as u64) << EROFS_BLOCK_BITS_9;
             let size = if idx == self.get_chunk_count() - 1 {
                 (self.size() % self.chunk_size() as u64) as u32
             } else {