MRP-1263 llite: lustre writepages address space operation

When a client generates dirty pages faster than servers commit them to
disk, it may lead to OOM. Pages sent to servers are not marked dirty.
That confuses write throttling so that it allows to generate more
dirty pages when it should throttle a writer.

This patch turns pages sent to server but not yet committed into dirty
memory accounting and implements writepages address space operation
for lustre:
- count those pages as unstable_nfs
- on background writeback: send OST_SYNC rpc to OSTs with pending
  commits
- on foreground writeback: send OST_SYNC rpc to OSTs with pending
  commits and wait for completion. When there is already in flight
  foreground writeback on an OST, wait for its completion as well.
- for "old" data flushing generic_writepages is called only

Signed-off-by: Vladimir Saveliev <vladimir_saveliev@xyratex.com>
Change-Id: I6ef73bd61fda81cbc3da99bae965ddfcbd0e0281
Reviewed-on: http://morpheus.xyus.xyratex.com:8443/gerrit/709
Tested-by: Jenkins
Reviewed-by: Alexander Boyko <Alexander_Boyko@xyratex.com>
Tested-by: Elena Gryaznova <Elena_Gryaznova@xyratex.com>
Reviewed-by: Andrew Perepechko <Andrew_Perepechko@xyratex.com>
Reviewed-by: Vitaly Fertman <Vitaly_Fertman@xyratex.com>
MRP-1362 tests: Lustre Sanity test_101b hangs w/ OSTCOUNT>100

sanity.sh test_101b hangs during Lustre sanity test. This
is happening especially in cases where the $OSTCOUNT is
greater than 100.

Due to OSTCOUNT of more than 100, the ITERATION parameter
results in '0', which causes the 'reads' utility to run
in infinite 'for' loop. Thus resulting in a hang on such
setups.

This change would make necessary changes in FILE_LENGTH in
test_101b and its related routines(setup_101bc, ra_check)
so that, the test won't hang and would proceed rightly.

Author: Parinay Kondekar <Parinay_Kondekar@xyratex.com>

Signed-off-by: Parinay Kondekar <Parinay_Kondekar@xyratex.com>
Change-Id: Ida4b54f5129c9577dbb966289d7d18aec7071f0c
Reviewed-on: http://morpheus.xyus.xyratex.com:8443/gerrit/715
Tested-by: Jenkins
Reviewed-by: Alexander Boyko <Alexander_Boyko@xyratex.com>
Tested-by: Elena Gryaznova <Elena_Gryaznova@xyratex.com>
Reviewed-by: Vladimir Saveliev <vladimir_saveliev@xyratex.com>
Reviewed-by: Vitaly Fertman <Vitaly_Fertman@xyratex.com>
MRP-1470 wrong arguments to save_lustre_params

sanityn.sh tests 52 and 53, sanity.sh test 226,
recovery-small.sh test 106 need to be updated according
to commit 8246cdfde57801061a305e10aaf8d39551c27a6e.

Change-Id: I62cb14063f9d33290b0b512fcb042ee38e7d62c2
Reviewed-on: http://morpheus.xyus.xyratex.com:8443/gerrit/918
Tested-by: Jenkins
Tested-by: Elena Gryaznova <Elena_Gryaznova@xyratex.com>
Reviewed-by: Elena Gryaznova <Elena_Gryaznova@xyratex.com>
MRP-1472: sanity defect: 2 test_226 ()

synchronize test number with Intel tree

Change-Id: I4f639c8960cf4f84b452ccca20b352b02617ff9a
Signed-off-by: Andriy Skulysh <Andriy_Skulysh@xyratex.com>
Reviewed-on: http://morpheus.xyus.xyratex.com:8443/gerrit/921
Tested-by: Jenkins
Tested-by: Elena Gryaznova <Elena_Gryaznova@xyratex.com>
Reviewed-by: Elena Gryaznova <Elena_Gryaznova@xyratex.com>