From: Tina Ruchandani Date: Tue, 7 Apr 2015 23:43:58 +0000 (+1000) Subject: ocfs2: use 64bit variables to track heartbeat time X-Git-Tag: KARO-TXA5-2015-06-26~18^2~463 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=29c2fe4b00d3ff9f31270f4415a65290742b3b22;p=karo-tx-linux.git ocfs2: use 64bit variables to track heartbeat time o2hb_elapsed_msecs computes the time taken for a disk heartbeat. 'struct timeval' variables are used to store start and end times. On 32-bit systems, the 'tv_sec' component of 'struct timeval' will overflow in year 2038 and beyond. This patch solves the overflow with the following: 1. Replace o2hb_elapsed_msecs using 'ktime_t' values to measure start and end time, and built-in function 'ktime_ms_delta' to compute the elapsed time. ktime_get_real() is used since the code prints out the wallclock time. 2. Changes format string to print time as a single 64-bit nanoseconds value ("%lld") instead of seconds and microseconds. This simplifies the code since converting ktime_t to that format would need expensive computation. However, the debug log string is less readable than the previous format. Signed-off-by: Tina Ruchandani Suggested by: Arnd Bergmann Cc: Mark Fasheh Cc: Joel Becker Signed-off-by: Andrew Morton --- diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c index 8e19b9d7aba8..0870fffd2a35 100644 --- a/fs/ocfs2/cluster/heartbeat.c +++ b/fs/ocfs2/cluster/heartbeat.c @@ -36,7 +36,7 @@ #include #include #include - +#include #include "heartbeat.h" #include "tcp.h" #include "nodemanager.h" @@ -1061,37 +1061,6 @@ bail: return ret; } -/* Subtract b from a, storing the result in a. a *must* have a larger - * value than b. */ -static void o2hb_tv_subtract(struct timeval *a, - struct timeval *b) -{ - /* just return 0 when a is after b */ - if (a->tv_sec < b->tv_sec || - (a->tv_sec == b->tv_sec && a->tv_usec < b->tv_usec)) { - a->tv_sec = 0; - a->tv_usec = 0; - return; - } - - a->tv_sec -= b->tv_sec; - a->tv_usec -= b->tv_usec; - while ( a->tv_usec < 0 ) { - a->tv_sec--; - a->tv_usec += 1000000; - } -} - -static unsigned int o2hb_elapsed_msecs(struct timeval *start, - struct timeval *end) -{ - struct timeval res = *end; - - o2hb_tv_subtract(&res, start); - - return res.tv_sec * 1000 + res.tv_usec / 1000; -} - /* * we ride the region ref that the region dir holds. before the region * dir is removed and drops it ref it will wait to tear down this @@ -1102,7 +1071,7 @@ static int o2hb_thread(void *data) int i, ret; struct o2hb_region *reg = data; struct o2hb_bio_wait_ctxt write_wc; - struct timeval before_hb, after_hb; + ktime_t before_hb, after_hb; unsigned int elapsed_msec; mlog(ML_HEARTBEAT|ML_KTHREAD, "hb thread running\n"); @@ -1119,18 +1088,18 @@ static int o2hb_thread(void *data) * hr_timeout_ms between disk writes. On busy systems * this should result in a heartbeat which is less * likely to time itself out. */ - do_gettimeofday(&before_hb); + before_hb = ktime_get_real(); ret = o2hb_do_disk_heartbeat(reg); - do_gettimeofday(&after_hb); - elapsed_msec = o2hb_elapsed_msecs(&before_hb, &after_hb); + after_hb = ktime_get_real(); + + elapsed_msec = (unsigned int) + ktime_ms_delta(after_hb, before_hb); mlog(ML_HEARTBEAT, - "start = %lu.%lu, end = %lu.%lu, msec = %u, ret = %d\n", - before_hb.tv_sec, (unsigned long) before_hb.tv_usec, - after_hb.tv_sec, (unsigned long) after_hb.tv_usec, - elapsed_msec, ret); + "start = %lld, end = %lld, msec = %u, ret = %d\n", + before_hb.tv64, after_hb.tv64, elapsed_msec, ret); if (!kthread_should_stop() && elapsed_msec < reg->hr_timeout_ms) {