From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [IPv6:2a01:7e0:0:424::9]) by lore.proxmox.com (Postfix) with ESMTPS id 224631FF183 for ; Wed, 8 Oct 2025 17:21:38 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id B4261C1B4; Wed, 8 Oct 2025 17:21:40 +0200 (CEST) From: Christian Ebner To: pbs-devel@lists.proxmox.com Date: Wed, 8 Oct 2025 17:21:16 +0200 Message-ID: <20251008152125.849216-4-c.ebner@proxmox.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20251008152125.849216-1-c.ebner@proxmox.com> References: <20251008152125.849216-1-c.ebner@proxmox.com> MIME-Version: 1.0 X-Bm-Milter-Handled: 55990f41-d878-4baa-be0a-ee34c49e34d2 X-Bm-Transport-Timestamp: 1759936867146 X-SPAM-LEVEL: Spam detection results: 0 AWL 0.043 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% DMARC_MISSING 0.1 Missing DMARC policy 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 Subject: [pbs-devel] [PATCH proxmox-backup v2 03/12] chunk store: add unsafe signature to cache remove method 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: , Reply-To: Proxmox Backup Server development discussion Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: pbs-devel-bounces@lists.proxmox.com Sender: "pbs-devel" Removing a chunk file from the local datastore cache is rather unsafe as several preconditions have to be met: - The chunk store mutex guard has to be held, in order to avoid concurrent operations on the chunk file - It must be assured that the chunk to be removed is not referenced by any visible index file. - It must be assured that the chunk is not being indexed by an active index writer (ongoing backup). - It must be assured that the chunk is not being indexed by an active index writer in an old process, still active after service reload (ongoing backup in old process). Add the unsafe signature to `LocalDatastoreLRUCache::remove()` to signal these preconditions and limit the scope to be crate only. Signed-off-by: Christian Ebner --- pbs-datastore/src/datastore.rs | 2 +- pbs-datastore/src/local_datastore_lru_cache.rs | 10 +++++++++- 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/pbs-datastore/src/datastore.rs b/pbs-datastore/src/datastore.rs index 7ef16c31e..acf22e9b0 100644 --- a/pbs-datastore/src/datastore.rs +++ b/pbs-datastore/src/datastore.rs @@ -1686,7 +1686,7 @@ impl DataStore { |_status| { if let Some(cache) = self.cache() { // ignore errors, phase 3 will retry cleanup anyways - let _ = cache.remove(&digest); + let _ = unsafe { cache.remove(&digest) }; } delete_list.push(content.key); Ok(()) diff --git a/pbs-datastore/src/local_datastore_lru_cache.rs b/pbs-datastore/src/local_datastore_lru_cache.rs index c0edd3619..12b7f0aaa 100644 --- a/pbs-datastore/src/local_datastore_lru_cache.rs +++ b/pbs-datastore/src/local_datastore_lru_cache.rs @@ -86,8 +86,16 @@ impl LocalDatastoreLruCache { /// Remove a chunk from the local datastore cache. /// + /// Callers to this method must assure that: + /// - no concurrent insert is being performed, the chunk store's mutex must be held. + /// - the chunk to be removed is no longer referenced by an index file. + /// - the chunk to be removed has not been inserted by an active writer (atime newer than + /// writer start time). + /// - there is no active writer in an old process, which could have inserted the chunk to be + /// deleted. + /// /// Fails if the chunk cannot be deleted successfully. - pub fn remove(&self, digest: &[u8; 32]) -> Result<(), Error> { + 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) -- 2.47.3 _______________________________________________ pbs-devel mailing list pbs-devel@lists.proxmox.com https://lists.proxmox.com/cgi-bin/mailman/listinfo/pbs-devel