features/bitrot: reimplement scrubbing frequency

This patch reimplments existing scrub-frequency mechanism used
to schedule scrubber runs. Existing mechanism uses periodic
sleeps (waking up periodically on minimum granularity) and
performing a number of tracking checks based on counters and
sleep times. This patch does away with all the nifty counters
and uses timer-wheel to schedule scrub runs.

Scheduling changes are peformed by merely calculating the new
expiry time and calling mod_timer() [mod_timer_pending() in
some cases] making the code more debuggable and easier to
follow. This also introduces "hourly" scrubbing tunable as an
aid for testing scrubbing during development/testing cycle.

One could also implement on-demand scrubbing with ease: by
invoking mod_timer() with an expiry of one (1) second, thereby
scheduling a scrub run the very next second.

Change-Id: I6c7c5f0c6c9f886bf574d88c04cde14b76e60a8b
BUG: 1224596
Signed-off-by: Venky Shankar <vshankar@redhat.com>
Reviewed-on: http://review.gluster.org/10893
Reviewed-by: Gaurav Kumar Garg <ggarg@redhat.com>
Tested-by: NetBSD Build System
Reviewed-by: Vijay Bellur <vbellur@redhat.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/xlators/features/bit-rot/src/bitd/bit-rot-scrub.h b/xlators/features/bit-rot/src/bitd/bit-rot-scrub.h
index 4f00020d66a..6c4254a397a 100644
--- a/xlators/features/bit-rot/src/bitd/bit-rot-scrub.h
+++ b/xlators/features/bit-rot/src/bitd/bit-rot-scrub.h
@@ -16,6 +16,12 @@
 
 void *br_fsscanner (void *);
 
+int32_t br_fsscan_schedule (xlator_t *, br_child_t *,
+                            struct br_scanfs *, struct br_scrubber *);
+int32_t br_fsscan_reschedule (xlator_t *this,
+                              br_child_t *child, struct br_scanfs *,
+                              struct br_scrubber *, gf_boolean_t);
+
 int32_t br_scrubber_handle_options (xlator_t *, br_private_t *, dict_t *);
 
 int32_t br_scrubber_init (xlator_t *, br_private_t *);