From: Philipp Reisner <philipp.reisner@linbit.com>
Date: Mon, 28 Apr 2014 16:43:12 +0000 (+0200)
Subject: drbd: Break a deadlock while concurrent fencing and establishing a connection
X-Git-Tag: omap-for-v3.16/fixes-against-rc1~39^2~47^2~47
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=31007745a5f328b8d70d865c4a6118be01421b8c;p=pandora-kernel.git

drbd: Break a deadlock while concurrent fencing and establishing a connection

When we need to outdate the peer while being promoted to primary,
and the connection gets established at the same time, we deadlock
in drbd_try_outdate_peer() when trying to clear the susp_fen
bit.

Fix this by setting the STATE_SENT bit while holding the mutex.

Using drbd_change_state(.. , CS_HARD, ..) which does not block
until STATE_SENT is cleared, is only for clearness. It does
not contribute anything to the fix.

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