MRP-1989 tests: deactivate OST during write

Test catches the situation when lqc_import==NULL(OST is deactivated)
but obd_commitrw transaction is not finished. In such case
ll_ost_io_xx may lock a set of pages that are also could be needed
by another tasks to prepare for write operation(obd_preprw). This
may cause high Load Average picture. Also tasks making write will
sleep indefinitely or until OST will be activated.

Signed-off-by: Alexander Boyko <alexander_boyko@xyratex.com>
Change-Id: I564989f922006b8ecf6542eee3f8f5813c323ae0
Reviewed-on: http://es-gerrit.xyus.xyratex.com:8080/3738
Tested-by: Jenkins
Reviewed-by: Sergey Cheremencev <sergey_cheremencev@xyratex.com>
Reviewed-by: Andrew Perepechko <andrew_perepechko@xyratex.com>
Tested-by: Alexander Lezhoev <alexander_lezhoev@xyratex.com>
Reviewed-by: Vitaly Fertman <vitaly.fertman@seagate.com>
MRP-1989 quota: prevent wait at quota_chk_ack_common

When OST device is deactivated, and osc-mdt is evicted from OST,
ost_brw_write lock the pages and sleep at

[<ffffffffa0ec167e>] cfs_waitq_wait+0xe/0x10 [libcfs]
[<ffffffffa0891260>] quota_chk_acq_common+0x970/0xc50 [lquota]
[<ffffffffa0b6197c>] filter_commitrw_write+0xbac/0x3388 [obdfilter]
[<ffffffffa0b5566f>] filter_commitrw+0x27f/0x2a0 [obdfilter]
[<ffffffffa0b132d6>] obd_commitrw+0x126/0x3d0 [ost]
[<ffffffffa0b1bec4>] ost_brw_write+0x1314/0x1af0 [ost]
[<ffffffffa0b22718>] ost_handle+0x3e38/0x45a0 [ost]

Other ll_ost_io threads which want to lock the same pages,
will hangs too. This wait was designed for MDS failover,
client IO should not be affected in this case. But no
need to wait for quota master infinitely.
Patch adds ability to stop waiting when client reconnected
or failed, and defines max timeout for this wait.

In this case brw resends could not occupy all ost_io threads
and hangs. The script looks like:
1) client send brw
2) ost thread lock pages and wait at quota_chk_acq_common()
3) client see brw request timeout, reconnect and resend brw
4) ost detects client reconnection during wait and
   return -ENOTCONN from quota_chk_ack_common for first brw
5) brw resend repeats wait at quota_chk_ack_common() again

This patch resolves the issue with ll_ost_io hang threads.

Signed-off-by: Alexander Boyko <alexander_boyko@xyratex.com>
Change-Id: I0f8a131d822aa7dea0dfacda8e2726b5eb0d339f
Reviewed-on: http://es-gerrit.xyus.xyratex.com:8080/3781
Reviewed-by: Andrew Perepechko <andrew_perepechko@xyratex.com>
Tested-by: Jenkins
Reviewed-by: Sergey Cheremencev <sergey_cheremencev@xyratex.com>
Tested-by: Alexander Lezhoev <alexander_lezhoev@xyratex.com>
Reviewed-by: Andriy Skulysh <andriy_skulysh@xyratex.com>
Reviewed-by: Vitaly Fertman <vitaly.fertman@seagate.com>