From: Philipp Reisner <philipp.reisner@linbit.com>
Date: Sun, 19 Feb 2012 00:27:53 +0000 (+0100)
Subject: drbd: Fix a potential write ordering issue on SyncTarget nodes
X-Git-Tag: v3.5-rc1~41^2^2~23
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b6a370ba0786b5eb09c479bffeffe7baba484ab0;p=pandora-kernel.git

drbd: Fix a potential write ordering issue on SyncTarget nodes

If a SyncTarget node gets a P_RS_DATA_REPLY before a P_DATA packet
for the same sector, it simply submits these two IO requests.

  This is be possible because on the SyncSource node, the data of the
  P_RS_DATA_REPLY packet was read from disk.  Immediately after that a
  write request from upper layers came in.

The disk scheduler or even the "hardware" queues on the disk drive might
reorder these writes.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---

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