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 CB58F64776 for ; Mon, 20 Jul 2020 17:02:27 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id B1978F4E0 for ; Mon, 20 Jul 2020 17:02:27 +0200 (CEST) Received: from proxmox-new.maurer-it.com (proxmox-new.maurer-it.com [212.186.127.180]) (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 firstgate.proxmox.com (Proxmox) with ESMTPS id 6775DF4BF for ; Mon, 20 Jul 2020 17:02:26 +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 29AD043263 for ; Mon, 20 Jul 2020 17:02:26 +0200 (CEST) From: Stefan Reiter To: pbs-devel@lists.proxmox.com Date: Mon, 20 Jul 2020 17:02:17 +0200 Message-Id: <20200720150220.22996-1-s.reiter@proxmox.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SPAM-LEVEL: Spam detection results: 0 AWL 0.029 Adjusted score from AWL reputation of From: address KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment RCVD_IN_DNSWL_MED -2.3 Sender listed at https://www.dnswl.org/, medium trust 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 0/3] Fix PBS blockdriver for non-VM settings 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, 20 Jul 2020 15:02:27 -0000 When using the PBS blockdriver with qemu-nbd (for example), it can happen that enough read requests are issued to saturate the tokio thread pool. Not an issue in general, but as me and Wolfgang painstakenly discovered a while back, it does break block_on, which is used in BufferedFixedReader. This means that reading larger amounts of data would hang the QEMU process [0]. Fix this by making the entire BufferedFixedReader API async, thus not requiring a block_on. Additionally I discovered a seperate bug (fixed by patch 3), wherein read requests that we're not aligned to the chunk size would return bogus data. This too only seems to happen in non-VM connections (e.g. nbd, etc...). [0] ...and since the NBD kernel driver appears to be horribly broken, this often also crashes most of the system, but that's a different story. If you ever get in this situation, 'nbd-client -d /dev/nbdX' works (sometimes) to force disconnect the device ('qemu-nbd -d' intelligently issues a read before disconnecting, thus hanging before getting anything done...) backup: Stefan Reiter (1): make BufferedFixedReader async src/backup/fixed_index.rs | 145 ++++++++++---------------------------- 1 file changed, 37 insertions(+), 108 deletions(-) backup-qemu: Stefan Reiter (1): use new async BufferedFixedReader API src/restore.rs | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) qemu: Stefan Reiter (1): PVE: PBS: iterate read_image_at until all data is available block/pbs.c | 31 ++++++++++++++++++++++--------- 1 file changed, 22 insertions(+), 9 deletions(-) -- 2.20.1