Make a shortcut for raw mode file:write_file.

And use it throughout. This prevents file:write_file going through
file_server_2.

Change-Id: Ib5c375d70de6ca40a5e9b75c6fb7bbcee7ef35a7
Reviewed-on: http://review.couchbase.org/38504
Tested-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Add behaviour annotation.

Change-Id: I6186fe7c546bffe8cec200832d16eb6f15a4c46b
Reviewed-on: http://review.couchbase.org/38505
Tested-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Handle nonexistent directory in godu itself.

Because file:read_file_info goes through file_server_2.

Change-Id: If3fde278e210e4e6f92cbe59fd2f94ec9a9e9e65
Reviewed-on: http://review.couchbase.org/38506
Tested-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reset lastError and errorCount after every request.

Change-Id: I5b073e3a7c88325fcffc5d9aebb1d3d042c797cd
Reviewed-on: http://review.couchbase.org/38507
Tested-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Use send_after to reschedule stats refresh.

To not accumulate refresh_stats messages if we're stuck.

Change-Id: I37fd39cbe9a33c8d95c1d9dde50bec20fa876c20
Reviewed-on: http://review.couchbase.org/38508
Tested-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Never drop requests to dir_size on the floor.

Change-Id: I0c18ad97f5f26bfa8765fe1820b765c883bfb663
Reviewed-on: http://review.couchbase.org/38509
Tested-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>