diskstats: Ensure collecting right space metrics

Check before writing space metrics to database that they where collected
for the right disk.

diff --git a/src/proc_diskstats.c b/src/proc_diskstats.c
index 26e9f110ae97980f37c45202fc50d6c52beac5d2..2b017ac26f3ff420f03f20043c7a8427683659f9 100644 (file)
--- a/src/proc_diskstats.c
+++ b/src/proc_diskstats.c
@@ -6,6 +6,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/stat.h>
 #include <sys/statvfs.h>
 #include <sys/types.h>
 #include <unistd.h>
@@ -138,6 +139,7 @@ int do_proc_diskstats(int update_every, unsigned long long dt) {
        static int enable_new_disks = -1;
        static int do_io = -1, do_ops = -1, do_mops = -1, do_iotime = -1, do_qops = -1, do_util = -1, do_backlog = -1, do_space = -1;
        static struct statvfs buff_statvfs;
+       static struct stat buff_stat;
 
        if(enable_new_disks == -1)      enable_new_disks = config_get_boolean_ondemand("plugin:proc:/proc/diskstats", "enable new disks detected at runtime", CONFIG_ONDEMAND_ONDEMAND);
 
@@ -667,34 +669,37 @@ int do_proc_diskstats(int update_every, unsigned long long dt) {
 
                // --------------------------------------------------------------------
 
-               if(ddo_space) {
-                       if(!mount_point) {
-                               if(ddo_space != CONFIG_ONDEMAND_ONDEMAND) {
-                                       error("Cannot find space usage for disk %s. It does not have a mount point.", family);
-                               }
+               if(ddo_space && mount_point) {
+                       // collect space metrics using statvfs
+                       if (statvfs(mount_point, &buff_statvfs) < 0) {
+                               error("Failed checking disk space usage of %s", family);
                        } else {
-                               if (statvfs(family, &buff_statvfs) < 0) {
-                                       error("Failed checking disk space usage of %s", family);
+                               // verify we collected the metrics for the right disk.
+                               // if not the mountpoint has changed.
+                               if(stat(mount_point, &buff_stat) == -1) {
                                } else {
-                                       space_avail = buff_statvfs.f_bavail * buff_statvfs.f_bsize;
-                                       space_avail_root = (buff_statvfs.f_bfree - buff_statvfs.f_bavail) * buff_statvfs.f_bsize;
-                                       space_used = (buff_statvfs.f_blocks - buff_statvfs.f_bfree) * buff_statvfs.f_bsize;
-
-                                       st = rrdset_find_bytype("disk_space", disk);
-                                       if(!st) {
-                                               st = rrdset_create("disk_space", disk, NULL, family, "disk.space", "Disk Space Usage", "GB", 2023, update_every, RRDSET_TYPE_STACKED);
-                                               st->isdetail = 1;
-
-                                               rrddim_add(st, "avail", NULL, 1, 1000*1000*1000, RRDDIM_ABSOLUTE);
-                                               rrddim_add(st, "reserved_for_root", "reserved for root", 1, 1000*1000*1000, RRDDIM_ABSOLUTE);
-                                               rrddim_add(st, "used" , NULL, 1, 1000*1000*1000, RRDDIM_ABSOLUTE);
-                                       }
-                                       else rrdset_next_usec(st, dt);
+                                       if(major(buff_stat.st_dev) == major && minor(buff_stat.st_dev) == minor)
+                                       {
+                                               space_avail = buff_statvfs.f_bavail * buff_statvfs.f_bsize;
+                                               space_avail_root = (buff_statvfs.f_bfree - buff_statvfs.f_bavail) * buff_statvfs.f_bsize;
+                                               space_used = (buff_statvfs.f_blocks - buff_statvfs.f_bfree) * buff_statvfs.f_bsize;
+
+                                               st = rrdset_find_bytype("disk_space", disk);
+                                               if(!st) {
+                                                       st = rrdset_create("disk_space", disk, NULL, family, "disk.space", "Disk Space Usage", "GB", 2023, update_every, RRDSET_TYPE_STACKED);
+                                                       st->isdetail = 1;
+
+                                                       rrddim_add(st, "avail", NULL, 1, 1000*1000*1000, RRDDIM_ABSOLUTE);
+                                                       rrddim_add(st, "reserved_for_root", "reserved for root", 1, 1000*1000*1000, RRDDIM_ABSOLUTE);
+                                                       rrddim_add(st, "used" , NULL, 1, 1000*1000*1000, RRDDIM_ABSOLUTE);
+                                               }
+                                               else rrdset_next_usec(st, dt);
 
-                                       rrddim_set(st, "avail", space_avail);
-                                       rrddim_set(st, "reserved_for_root", space_avail_root);
-                                       rrddim_set(st, "used", space_used);
-                                       rrdset_done(st);
+                                               rrddim_set(st, "avail", space_avail);
+                                               rrddim_set(st, "reserved_for_root", space_avail_root);
+                                               rrddim_set(st, "used", space_used);
+                                               rrdset_done(st);
+                                       }
                                }
                        }
                }