feat: notifying incosistent fs version problem with exit code

If acceld converts with different fs version cache, leading to an inconsistent fs version problem when merging into boostrap layer. So we need to notify acceld that an inconsistent version occured and handle this error.

Signed-off-by: YuQiang <y_q_email@163.com>

rafs/Cargo.toml

@@ -20,6 +20,7 @@ serde = { version = "1.0.110", features = ["serde_derive", "rc"] }
 serde_json = "1.0.53"
 vm-memory = "0.10"
 fuse-backend-rs = "^0.10.3"
+thiserror = "1"
 
 nydus-api = { version = "0.3", path = "../api" }
 nydus-storage = { version = "0.6", path = "../storage", features = ["backend-localfs"] }

rafs/src/metadata/mod.rs

@@ -17,8 +17,10 @@ use std::path::{Component, Path, PathBuf};
 use std::str::FromStr;
 use std::sync::Arc;
 use std::time::Duration;
+use thiserror::Error;
 
 use anyhow::bail;
+use anyhow::Result as AnyhowResult;
 use fuse_backend_rs::abi::fuse_abi::Attr;
 use fuse_backend_rs::api::filesystem::Entry;
 use nydus_api::{ConfigV2, RafsConfigV2};
@@ -397,34 +399,44 @@ pub struct RafsSuperConfig {
     pub is_tarfs_mode: bool,
 }
 
+#[derive(Error, Debug)]
+pub enum MergeError {
+    #[error("Inconsistent RAFS version:{0}")]
+    InconsisentFsVersion(String),
+    #[error("Different Digest Algorithm:{0}")]
+    DifferentDigestAlgorithm(String),
+    #[error(transparent)]
+    Other(#[from] Error),
+}
+
 impl RafsSuperConfig {
     /// Check compatibility for two RAFS filesystems.
-    pub fn check_compatibility(&self, meta: &RafsSuperMeta) -> Result<()> {
+    pub fn check_compatibility(&self, meta: &RafsSuperMeta) -> AnyhowResult<(), MergeError> {
         if self.chunk_size != meta.chunk_size {
-            return Err(einval!(format!(
+            return Err(MergeError::InconsisentFsVersion(format!(
                 "Inconsistent configuration of chunk_size: {} vs {}",
                 self.chunk_size, meta.chunk_size
             )));
         }
 
         if self.explicit_uidgid != meta.explicit_uidgid() {
-            return Err(einval!(format!(
+            return Err(MergeError::InconsisentFsVersion(format!(
                 "Using inconsistent explicit_uidgid setting {:?}, target explicit_uidgid setting {:?}",
                 self.explicit_uidgid,
                 meta.explicit_uidgid()
             )));
         }
 
         if u32::from(self.version) != meta.version {
-            return Err(einval!(format!(
+            let meta_version = RafsVersion::try_from(meta.version);
+            return Err(MergeError::InconsisentFsVersion(format!(
                 "Using inconsistent RAFS version {:?}, target RAFS version {:?}",
-                self.version,
-                RafsVersion::try_from(meta.version)?
+                self.version, meta_version
             )));
         }
 
         if self.version == RafsVersion::V5 && self.digester != meta.get_digester() {
-            return Err(einval!(format!(
+            return Err(MergeError::DifferentDigestAlgorithm(format!(
                 "RAFS v5 can not support different digest algorithm due to inode digest, {} vs {}",
                 self.digester,
                 meta.get_digester()
@@ -433,7 +445,9 @@ impl RafsSuperConfig {
 
         let is_tarfs_mode = meta.flags.contains(RafsSuperFlags::TARTFS_MODE);
         if is_tarfs_mode != self.is_tarfs_mode {
-            return Err(einval!(format!("Using inconsistent RAFS TARFS mode")));
+            return Err(MergeError::InconsisentFsVersion(
+                "Using inconsistent RAFS TARFS mode".to_string(),
+            ));
         }
 
         Ok(())

src/bin/nydus-image/main.rs

@@ -31,7 +31,7 @@ use nydus_builder::{
     BuildContext, BuildOutput, Builder, ConversionType, DirectoryBuilder, Feature, Features,
     HashChunkDict, Merger, Prefetch, PrefetchPolicy, StargzBuilder, TarballBuilder, WhiteoutSpec,
 };
-use nydus_rafs::metadata::{RafsSuper, RafsSuperConfig, RafsVersion};
+use nydus_rafs::metadata::{MergeError, RafsSuper, RafsSuperConfig, RafsVersion};
 use nydus_storage::backend::localfs::LocalFs;
 use nydus_storage::backend::BlobBackend;
 use nydus_storage::device::{BlobFeatures, BlobInfo};
@@ -759,7 +759,13 @@ fn main() -> Result<()> {
             }
         }
     } else if let Some(matches) = cmd.subcommand_matches("merge") {
-        Command::merge(matches, &build_info)
+        let result = Command::merge(matches, &build_info);
+        if let Err(e) = result {
+            if let Some(MergeError::InconsisentFsVersion(_)) = e.downcast_ref::<MergeError>() {
+                std::process::exit(2);
+            }
+        }
+        Ok(())
     } else if let Some(matches) = cmd.subcommand_matches("check") {
         Command::check(matches, &build_info)
     } else if let Some(matches) = cmd.subcommand_matches("export") {