Problem:
afr_child_up_status_meta works only when LOOKUP on $M0 is successful.
There are cases where quorum is not met and LOOKUP fails on $M0 which
leads to failures similar to:
grep: /mnt/glusterfs/0/.meta/graphs/active/patchy-replicate-0/private: Transport endpoint is not connected
This was happening once in a while based on attribute-timeout and
md-cache not serving the lookup.

Fix:
Find child-up status based on statedump instead. Also changed mount
options to include --entry-timeout=0 and --attribute-timeout=0

updates bz#1193929
Change-Id: Ic0de72c3006d7399a5feb3e4d10d4748949b2ab3
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>

With this change when SHD starts the index crawl it requests
all the clients to release the AFR_TA_DOM_NOTIFY lock so that
clients will know the in memory state is no more valid and
any new operations needs to query the thin-arbiter if required.

When SHD completes healing all the files without any failure, it
will again take the AFR_TA_DOM_NOTIFY lock and gets the xattrs on
TA to see whether there are any new failures happened by that time.
If there are new failures marked on TA, SHD will start the crawl
immediately to heal those failures as well. If there are no new
failures, then SHD will take the AFR_TA_DOM_MODIFY lock and unsets
the xattrs on TA, so that both the data bricks will be considered
as good there after.

Change-Id: I037b89a0823648f314580ba0716d877bd5ddb1f1
fixes: bz#1579788
Signed-off-by: karthik-us <ksubrahm@redhat.com>