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[93.111.99.180]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-c2de104355fsm145093166b.19.2026.09.28.09.03.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 28 Sep 2026 09:03:51 -0700 (PDT) Date: Mon, 28 Sep 2026 18:03:49 +0200 From: Philipp Reisner To: Amirhossein Rahimi Cc: drbd-dev@lists.linux.dev Subject: Re: [BUG] DRBD 9.3.4: acknowledgement counter rewind and stalled resync after failover Message-ID: References: Precedence: bulk X-Mailing-List: drbd-dev@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Hello, thank you for the careful report. I can confirm the problem is real. We reproduced it in our lab and it now has an automated regression test. Your diagnosis points at the right place: a write that never gets a dagtag assigned can move the peer-acknowledgement tracking backwards, after which the resync waits for a flush acknowledgement that is never sent. That also explains why the data compared equal — nothing was actually out of sync. A fix is in review. We expect to have it available within the next few days, and I will come back to you once it is merged. Best regards, Philipp