From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [212.224.123.68]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.proxmox.com (Postfix) with ESMTPS id 01EDB70C90 for ; Mon, 9 May 2022 16:09:09 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id E96362D45B for ; Mon, 9 May 2022 16:09:08 +0200 (CEST) Received: from proxmox-new.maurer-it.com (proxmox-new.maurer-it.com [94.136.29.106]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by firstgate.proxmox.com (Proxmox) with ESMTPS id 12A5B2D450 for ; Mon, 9 May 2022 16:09:08 +0200 (CEST) Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id C51EC42215 for ; Mon, 9 May 2022 16:09:07 +0200 (CEST) From: Dominik Csapak To: pbs-devel@lists.proxmox.com Date: Mon, 9 May 2022 16:09:06 +0200 Message-Id: <20220509140906.3488498-1-d.csapak@proxmox.com> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SPAM-LEVEL: Spam detection results: 0 AWL 0.119 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record T_SCC_BODY_TEXT_LINE -0.01 - Subject: [pbs-devel] [PATCH proxmox-backup v2] chunk_store: insert_chunk: write chunk again if it is empty on disk X-BeenThere: pbs-devel@lists.proxmox.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Proxmox Backup Server development discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 09 May 2022 14:09:09 -0000 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 --- replaces: https://lists.proxmox.com/pipermail/pbs-devel/2022-May/005042.html changes from v1: * warn only on old_size == 0 * fix old_size/new_size * expand commit message we could do further checks here, but those should be caught by verify. the 'real' fix for most of the 0-size chunks will be to either fsync the chunks after write/rename, or do a syncfs before the backup ends 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 {} - {}", -- 2.30.2