From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [212.224.123.68]) by lore.proxmox.com (Postfix) with ESMTPS id 34F581FF187 for ; Mon, 6 Oct 2025 15:18:16 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id BA3384BBA; Mon, 6 Oct 2025 15:18:19 +0200 (CEST) Date: Mon, 06 Oct 2025 15:18:13 +0200 From: Fabian =?iso-8859-1?q?Gr=FCnbichler?= To: Proxmox Backup Server development discussion References: <20251006104151.487202-1-c.ebner@proxmox.com> <20251006104151.487202-7-c.ebner@proxmox.com> In-Reply-To: <20251006104151.487202-7-c.ebner@proxmox.com> MIME-Version: 1.0 User-Agent: astroid/0.17.0 (https://github.com/astroidmail/astroid) Message-Id: <1759754434.n5p51h47f1.astroid@yuna.none> X-Bm-Milter-Handled: 55990f41-d878-4baa-be0a-ee34c49e34d2 X-Bm-Transport-Timestamp: 1759756667803 X-SPAM-LEVEL: Spam detection results: 0 AWL 0.049 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: Re: [pbs-devel] [PATCH proxmox-backup 6/7] api: chunk upload: fix race with garbage collection for no-cache on s3 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" On October 6, 2025 12:41 pm, Christian Ebner wrote: > Chunks uploaded to the s3 backend are never inserted into the local > datastore cache. The presence of the chunk marker file is however > required for garbage collection to not cleanup the chunks. While the > marker files are created during phase 1 of the garbage collection for > indexed chunks, this is not the case for in progress backups with the > no-cache flag set. > > Therefore, mark chunks as in-progress while being uploaded just like > for the regular mode with cache, but replace this with the zero-sized > chunk marker file after upload finished to avoid incorrect garbage > collection cleanup. > > Signed-off-by: Christian Ebner > --- > pbs-datastore/src/chunk_store.rs | 13 +++++++++++++ > pbs-datastore/src/datastore.rs | 7 +++++++ > src/api2/backup/upload_chunk.rs | 12 ++++++++++-- > 3 files changed, 30 insertions(+), 2 deletions(-) > > diff --git a/pbs-datastore/src/chunk_store.rs b/pbs-datastore/src/chunk_store.rs > index 22efe4a32..7fd92b626 100644 > --- a/pbs-datastore/src/chunk_store.rs > +++ b/pbs-datastore/src/chunk_store.rs > @@ -594,6 +594,19 @@ impl ChunkStore { > Ok(()) > } > > + pub(crate) fn persist_backend_upload_marker(&self, digest: &[u8; 32]) -> Result<(), Error> { > + if self.datastore_backend_type == DatastoreBackendType::Filesystem { > + bail!("cannot create backend upload marker, not a cache store"); > + } > + let (marker_path, _digest_str) = self.chunk_backed_upload_marker_path(digest); > + let (chunk_path, digest_str) = self.chunk_path(digest); > + let _lock = self.mutex.lock(); > + > + std::fs::rename(marker_path, chunk_path).map_err(|err| { > + format_err!("persisting backup upload marker failed for {digest_str} - {err}") > + }) > + } > + > pub(crate) fn cleanup_backend_upload_marker(&self, digest: &[u8; 32]) -> Result<(), Error> { > if self.datastore_backend_type == DatastoreBackendType::Filesystem { > bail!("cannot cleanup backend upload marker, not a cache store"); > diff --git a/pbs-datastore/src/datastore.rs b/pbs-datastore/src/datastore.rs > index 58fb863ec..8b0d4ab5c 100644 > --- a/pbs-datastore/src/datastore.rs > +++ b/pbs-datastore/src/datastore.rs > @@ -1894,6 +1894,13 @@ impl DataStore { > self.inner.chunk_store.insert_backend_upload_marker(digest) > } > > + /// Persist the backend upload marker to be a zero size chunk marker. > + /// > + /// Marks the chunk as present in the local store cache without inserting its payload. > + pub fn persist_backend_upload_marker(&self, digest: &[u8; 32]) -> Result<(), Error> { > + self.inner.chunk_store.persist_backend_upload_marker(digest) > + } > + > /// Remove the marker file signaling an in-progress upload to the backend > pub fn cleanup_backend_upload_marker(&self, digest: &[u8; 32]) -> Result<(), Error> { > self.inner.chunk_store.cleanup_backend_upload_marker(digest) > diff --git a/src/api2/backup/upload_chunk.rs b/src/api2/backup/upload_chunk.rs > index d4b1850eb..35d873ebf 100644 > --- a/src/api2/backup/upload_chunk.rs > +++ b/src/api2/backup/upload_chunk.rs > @@ -263,10 +263,18 @@ async fn upload_to_backend( > > if env.no_cache { > let object_key = pbs_datastore::s3::object_key_from_digest(&digest)?; > - let is_duplicate = s3_client > + env.datastore.insert_backend_upload_marker(&digest)?; this has the same issue as patch #5 - if two clients attempt to upload the same digest concurrently, then one of them will fail and abort the backup.. > + let is_duplicate = match s3_client > .upload_no_replace_with_retry(object_key, data) > .await > - .map_err(|err| format_err!("failed to upload chunk to s3 backend - {err:#}"))?; > + { > + Ok(is_duplicate) => is_duplicate, > + Err(err) => { > + datastore.cleanup_backend_upload_marker(&digest)?; > + bail!("failed to upload chunk to s3 backend - {err:#}"); > + } > + }; > + env.datastore.persist_backend_upload_marker(&digest)?; and if this fails, the corresponding chunk can never be uploaded again.. > return Ok((digest, size, encoded_size, is_duplicate)); > } > > -- > 2.47.3 > > > > _______________________________________________ > pbs-devel mailing list > pbs-devel@lists.proxmox.com > https://lists.proxmox.com/cgi-bin/mailman/listinfo/pbs-devel > > > _______________________________________________ pbs-devel mailing list pbs-devel@lists.proxmox.com https://lists.proxmox.com/cgi-bin/mailman/listinfo/pbs-devel