repository: Add some error context

This adds error context when opening images and streams. Without
this it is kinda hard to figure out what ENOENT really means.

Signed-off-by: Alexander Larsson <[email protected]>

Author: alexlarsson

crates/composefs/src/repository.rs

@@ -379,9 +379,11 @@ impl<ObjectID: FsVerityHashValue> Repository<ObjectID> {
         let filename = format!("streams/{name}");
 
         let file = File::from(if let Some(verity_hash) = verity {
-            self.open_with_verity(&filename, verity_hash)?
+            self.open_with_verity(&filename, verity_hash)
+                .with_context(|| format!("Opening ref 'streams/{name}'"))?
         } else {
-            self.openat(&filename, OFlags::RDONLY)?
+            self.openat(&filename, OFlags::RDONLY)
+                .with_context(|| format!("Opening ref 'streams/{name}'"))?
         });
 
         SplitStreamReader::new(file)
@@ -434,7 +436,8 @@ impl<ObjectID: FsVerityHashValue> Repository<ObjectID> {
     /// Returns the fd of the image and whether or not verity should be
     /// enabled when mounting it.
     fn open_image(&self, name: &str) -> Result<(OwnedFd, bool)> {
-        let image = self.openat(&format!("images/{name}"), OFlags::RDONLY)?;
+        let image = self.openat(&format!("images/{name}"), OFlags::RDONLY)
+            .with_context(|| format!("Opening ref 'images/{name}'"))?;
 
         if name.contains("/") {
             return Ok((image, true));