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[209.85.220.41]) by mx.google.com with SMTPS id ffacd0b85a97d-48e6eb5322csor2275889f8f.1.2026.11.03.00.37.10 for (Google Transport Security); Tue, 03 Nov 2026 00:37:10 -0800 (PST) Received-SPF: softfail (google.com: domain of transitioning den@openvz.org does not designate 2a06:5b06:b600:300:c789:8bc5:fa8e:d502 as permitted sender) client-ip=2a06:5b06:b600:300:c789:8bc5:fa8e:d502; Authentication-Results: mx.google.com; dkim=pass header.i=@openvz.org header.s=google header.b=uEASGw9n; spf=softfail (google.com: domain of transitioning den@openvz.org does not designate 2a06:5b06:b600:300:c789:8bc5:fa8e:d502 as permitted sender) smtp.mailfrom=den@openvz.org; dara=neutral header.i=@openvz.org DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=openvz.org; s=google; t=1793695030; x=1794299830; darn=openvz.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to:content-type; bh=x73Uct1MGgP1/P8fdBHsewYp2qAJBrxiJjoFboaawec=; b=uEASGw9nukEBWIZY6Teh5Y8tr8zJLauF/9uFS+onDo+MHBsVQ7QcVzGdf0vuv35AgN i6aZEvBwFqB/YsfUjuxhmEdnoUwricBXj4aLjxrca/DD9wfUx+rjNlT3ZfYOiKGlIi+R R4CBab1nVFAI3hOA34J4PMXeaaxCPquKWi2PCfcaFyVRgxHm1vPy/E7DmvtV8Nbw8kXv WsJiM1MYQgk8wkZ3LKOmnBmFMmf9m5JhMC7FcDEXp2zW3Wjtc/MPc8YeFHUSDOSgakZM XFm7iOOpfejgQt6OhBmODqutaIydOYDTLw/RZ/ufMtTSShnabQWLuRz5K8i1OBNzxx34 d7wA== X-Forwarded-Encrypted: i=1; AKwUvBxbU7S7eAxAiNjrdrOV5GjVMxKa4DtUP+YPETkaWGkxZaAzW8n64olMl9Oso51xADbMiD6iEw==@openvz.org X-Received: by 2002:a05:6000:1866:b0:48d:fdc0:65be with SMTP id ffacd0b85a97d-48e6e4ff7b1mr31112109f8f.38.1793695030412; Tue, 03 Nov 2026 00:37:10 -0800 (PST) Received: from athena.sw.ru ([2a06:5b06:b600:300:c789:8bc5:fa8e:d502]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-48e71b9b54dsm23304588f8f.47.2026.11.03.00.37.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 03 Nov 2026 00:37:10 -0800 (PST) From: "Denis V. Lunev" To: andrey.zhadchenko@virtuozzo.com Date: Tue, 3 Nov 2026 09:37:05 +0100 Message-ID: <20261103083708.131379-1-den@openvz.org> X-Mailer: git-send-email 2.53.0 MIME-Version: 1.0 X-OZ-Fwd: true Cc: devel@openvz.org Subject: [Devel] [PATCH hci-8.1 0/3] dm-qcow2: fix merges not stopping the users of the images they change X-BeenThere: devel@openvz.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: OpenVZ development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: devel-bounces@openvz.org Errors-To: devel-bounces@openvz.org Checking dm-qcow2 for the same problem showed that a merge does not stop everything using the images it changes (VSTOR-153049, VSTOR-153050): - a backward merge of an inner image pauses that image, while reads enter through the top one. A read reaching the inner image as the merge starts oopses on a NULL qio->ext (patch 2); - SEEK_HOLE/SEEK_DATA walks the images without an inflight ref, so merge_backward complete frees an image under the walk (patch 3). Patch 1 (VSTOR-153051) is the counterpart of dm-ploop patch 4, an error path leaving state behind: after a failed refcount table relocation, allocating writes past the old refcount coverage fail with EIO until the device is suspended and resumed. The series does not depend on the dm-ploop one. Tested on dev-cl04, stock 6.12.0-211.52.1.22.11.vz10, dm-qcow2 built out of tree, with a test-only kprobe module widening the windows: - on the stock module, with 4K clusters and refcount_bits=64 so the reftable relocates at 1G, a failed md page insert left every later write past 1G failing with EIO; a seek went on with an image qcow2_destroy() had freed; an intermediate merge oopsed in submit_read_sliced_clu(). None of them reproduce with the series; - the ploop pytest suite, qcow2 format, passes. Denis V. Lunev (3): dm-qcow2: fix a failed refcount table relocation leaking md pages dm-qcow2: fix backward merge of an inner image racing its reads dm-qcow2: fix SEEK_HOLE/SEEK_DATA using an image freed by a merge drivers/md/dm-qcow2-cmd.c | 26 ++++++++++---------------- drivers/md/dm-qcow2-map.c | 19 ++++++++++++++----- 2 files changed, 24 insertions(+), 21 deletions(-) base-commit: 09eb9a82fe872048d082391415d1cdeda2ac6879 -- 2.53.0 _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel