From dd612daab06c8746070d88d9d5b7a6cf200061a6 Mon Sep 17 00:00:00 2001 From: Dominik Csapak Date: Mon, 9 May 2022 16:09:06 +0200 Subject: [PATCH] chunk_store: insert_chunk: write chunk again if it is empty on disk and issue a warning. We can do this, because we know an empty chunk cannot be valid, and we (assumedly) have a valid chunk in memory. Having empty chunks on disk is currently possible when PBS crashes, but the rename of the chunk was flushed to disk, when the actual data was not. If it's not empty but there is a size mismatch, return an error. Signed-off-by: Dominik Csapak --- pbs-datastore/src/chunk_store.rs | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/pbs-datastore/src/chunk_store.rs b/pbs-datastore/src/chunk_store.rs index 8d7df513..85e7cc71 100644 --- a/pbs-datastore/src/chunk_store.rs +++ b/pbs-datastore/src/chunk_store.rs @@ -458,17 +458,26 @@ 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 old_size = metadata.len(); + if encoded_size == old_size { + self.touch_chunk(digest)?; + return Ok((true, old_size)); + } else if old_size == 0 { + log::warn!("found empty chunk '{digest_str}' on disk, overwriting"); + } else { + bail!("found chunk size mismatch for '{digest_str}': old {old_size} - new {encoded_size}"); + } } let mut tmp_path = chunk_path.clone(); @@ -483,9 +492,6 @@ 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 {} - {}",