[pbs-devel] [PATCH proxmox-backup] chunk_store: insert_chunk: write chunk again if sizes don't match

[Dominik Csapak]

if the on-disk size of a chunk is not correct, write it again when
inserting and log a warning.

This is currently possible if PBS crashes, but the rename of the chunk
was flushed to disk, when the actual data was not.

Suggested-by: Fabian Grünbichler <f.gruenbichler at proxmox.com>
Signed-off-by: Dominik Csapak <d.csapak at proxmox.com>
---
 pbs-datastore/src/chunk_store.rs | 23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/pbs-datastore/src/chunk_store.rs b/pbs-datastore/src/chunk_store.rs
index 8d7df513..93f56e8b 100644
--- a/pbs-datastore/src/chunk_store.rs
+++ b/pbs-datastore/src/chunk_store.rs
@@ -458,17 +458,29 @@ impl ChunkStore {
 
         let lock = self.mutex.lock();
 
+        let raw_data = chunk.raw_data();
+        let encoded_size = raw_data.len() as u64;
+
         if let Ok(metadata) = std::fs::metadata(&chunk_path) {
-            if metadata.is_file() {
-                self.touch_chunk(digest)?;
-                return Ok((true, metadata.len()));
-            } else {
+            if !metadata.is_file() {
                 bail!(
                     "Got unexpected file type on store '{}' for chunk {}",
                     self.name,
                     digest_str
                 );
             }
+            let new_len = metadata.len();
+            if encoded_size == new_len {
+                self.touch_chunk(digest)?;
+                return Ok((true, new_len));
+            } else {
+                log::warn!(
+                    "chunk size mismatch on insert for {}: old {} - new {}",
+                    digest_str,
+                    encoded_size,
+                    new_len
+                );
+            }
         }
 
         let mut tmp_path = chunk_path.clone();
@@ -483,9 +495,6 @@ impl ChunkStore {
             )
         })?;
 
-        let raw_data = chunk.raw_data();
-        let encoded_size = raw_data.len() as u64;
-
         file.write_all(raw_data).map_err(|err| {
             format_err!(
                 "writing temporary chunk on store '{}' failed for {} - {}",
-- 
2.30.2