From 0e49d7b014c5d591a053d08888a455bd74a88646 Mon Sep 17 00:00:00 2001 From: Lars Ellenberg Date: Mon, 28 Apr 2014 18:43:18 +0200 Subject: [PATCH] drbd: fix potential distributed deadlock during verify or resync If max-buffers and socket buffer sizes are "too small" for the chosen resync rate, this could lead potentially lead to a distributed deadlock, which may or may not resolve itself via the "ko-count" and request timeout mechanism, or could be resolved by forced disconnect. One option to deal with this is proper configuration: use larger max-buffer and socket buffers settings, or reduce the resync rate. But even with bad configuration we should not deadlock, but "gracefully" recover. The issue is avoided by using only up to max-buffers/2 for resync requests, and by using max-buffers not as a hard limit for data buffer allocations, but as a throttle threshold only. Signed-off-by: Philipp Reisner Signed-off-by: Lars Ellenberg Signed-off-by: Jens Axboe --- Reading git-format-patch failed