iostat: Make code a bit more solid

Add some extra verifications even though flush operations are normally
counted as writes before being merged.

Signed-off-by: Sebastien GODARD <sysstat@users.noreply.github.com>

diff --git a/iostat.c b/iostat.c
index 1d3c8e17dd2f75fb98186457053618653cd2d957..07c4dd7444df94bfa3977b29cf8148f296afc90b 100644 (file)
--- a/iostat.c
+++ b/iostat.c
@@ -617,13 +617,13 @@ void read_diskstats_stat(int curr)
        unsigned long dc_ios, dc_merges, dc_sec, fl_ios;
        unsigned int major, minor;
 
-       memset(&sdev, 0, sizeof(struct io_stats));
-
        if ((fp = fopen(DISKSTATS, "r")) == NULL)
                return;
 
        while (fgets(line, sizeof(line), fp) != NULL) {
 
+               memset(&sdev, 0, sizeof(struct io_stats));
+
                /* major minor name rio rmerge rsect ruse wio wmerge wsect wuse running use aveq dcio dcmerge dcsect dcuse flio fltm */
                i = sscanf(line, "%u %u %s %lu %lu %lu %lu %lu %lu %lu %u %u %u %u %lu %lu %lu %u %lu %u",
                           &major, &minor, dev_name,
@@ -1642,20 +1642,22 @@ void write_stats(int curr, struct tm *rectime, int skip)
                                ioj = d->dev_stats[!curr];
                                /* Origin (unmerged) flush operations are counted as writes */
                                if (!DISPLAY_UNFILTERED(flags)) {
-                                       if (!ioi->rd_ios && !ioi->wr_ios && !ioi->dc_ios)
+                                       if (!ioi->rd_ios && !ioi->wr_ios && !ioi->dc_ios && !ioi->fl_ios)
                                                continue;
                                }
 
                                if (DISPLAY_ZERO_OMIT(flags)) {
                                        if ((ioi->rd_ios == ioj->rd_ios) &&
                                            (ioi->wr_ios == ioj->wr_ios) &&
-                                           (ioi->dc_ios == ioj->dc_ios))
+                                           (ioi->dc_ios == ioj->dc_ios) &&
+                                           (ioi->fl_ios == ioj->fl_ios))
                                                /* No activity: Ignore it */
                                                continue;
                                }
 
                                /* Try to detect if device has been removed then inserted again */
-                               if (((ioi->rd_ios + ioi->wr_ios + ioi->dc_ios) < (ioj->rd_ios + ioj->wr_ios + ioj->dc_ios)) &&
+                               if (((ioi->rd_ios + ioi->wr_ios + ioi->dc_ios + ioi->fl_ios) <
+                                       (ioj->rd_ios + ioj->wr_ios + ioj->dc_ios + ioj->fl_ios)) &&
                                    (!ioj->rd_sectors || (ioi->rd_sectors < ioj->rd_sectors)) &&
                                    (!ioj->wr_sectors || (ioi->wr_sectors < ioj->wr_sectors)) &&
                                    (!ioj->dc_sectors || (ioi->dc_sectors < ioj->dc_sectors))) {