From: Lars Ellenberg <lars.ellenberg@linbit.com>
Date: Fri, 2 May 2014 11:20:05 +0000 (+0200)
Subject: drbd: debugfs: add in_flight_summary data
X-Git-Tag: omap-for-v3.17/fixes-against-rc2~74^2~12
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=db1866ffeed2e142208a801f7598326b92ebf7c5;p=pandora-kernel.git

drbd: debugfs: add in_flight_summary data

To help diagnosing "high latency" or "hung" IO situations on DRBD,
present per drbd resource group a summary of operations currently in progress.

First item is a list of oldest drbd_request objects
waiting for various things:
 * still being prepared
 * waiting for activity log transaction
 * waiting for local disk
 * waiting to be sent
 * waiting for peer acknowledgement ("receive ack", "write ack")
 * waiting for peer epoch acknowledgement ("barrier ack")

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