[pbs-devel] [PATCH proxmox-backup v3 21/23] chunk store: make chunk removal a helper method of the chunk store

[Christian Ebner]

Better encapsulate functionality which touches the chunk store, to
assure a common interface is used. The local datastore LRU cache will
call this during garbage collection to clean up chunk marker files
for chunks which have been removed from the S3 object store backend.

This is in preparation for fixing a deadlock, no functional changes
intended.

Signed-off-by: Christian Ebner <c.ebner at proxmox.com>
---
changes since version 2:
- not present in previous version

 pbs-datastore/src/chunk_store.rs               | 9 +++++++++
 pbs-datastore/src/local_datastore_lru_cache.rs | 3 +--
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/pbs-datastore/src/chunk_store.rs b/pbs-datastore/src/chunk_store.rs
index 426e14ef8..305ce2316 100644
--- a/pbs-datastore/src/chunk_store.rs
+++ b/pbs-datastore/src/chunk_store.rs
@@ -711,6 +711,15 @@ impl ChunkStore {
         Ok(())
     }
 
+    /// Removes a chunk marker file from the `LocalDatastoreLruCache`s chunk store.
+    ///
+    /// Callers must hold the per-chunk file lock in order to avoid races with renaming of corrupt
+    /// chunks by verifications and chunk inserts by backups.
+    pub(crate) fn remove_chunk(&self, digest: &[u8; 32]) -> Result<(), Error> {
+        let (chunk_path, _digest_str) = self.chunk_path(digest);
+        std::fs::remove_file(chunk_path).map_err(Error::from)
+    }
+
     pub fn relative_path(&self, path: &Path) -> PathBuf {
         // unwrap: only `None` in unit tests
         assert!(self.locker.is_some());
diff --git a/pbs-datastore/src/local_datastore_lru_cache.rs b/pbs-datastore/src/local_datastore_lru_cache.rs
index fe3b51a55..7b9d8caae 100644
--- a/pbs-datastore/src/local_datastore_lru_cache.rs
+++ b/pbs-datastore/src/local_datastore_lru_cache.rs
@@ -52,8 +52,7 @@ impl LocalDatastoreLruCache {
     /// Fails if the chunk cannot be deleted successfully.
     pub(crate) unsafe fn remove(&self, digest: &[u8; 32]) -> Result<(), Error> {
         self.cache.remove(*digest);
-        let (path, _digest_str) = self.store.chunk_path(digest);
-        std::fs::remove_file(path).map_err(Error::from)
+        self.store.remove_chunk(digest)
     }
 
     /// Access the locally cached chunk or fetch it from the S3 object store via the provided
-- 
2.47.3