path: root/src/proc_diskstats.c

#include "common.h"

#define RRD_TYPE_DISK "disk"

#define DISK_TYPE_PHYSICAL  1
#define DISK_TYPE_PARTITION 2
#define DISK_TYPE_CONTAINER 3

static struct disk {
    char *disk;             // the name of the disk (sda, sdb, etc)
    unsigned long major;
    unsigned long minor;
    int sector_size;
    int type;
    char *mount_point;

    // disk options caching
    int configured;
    int do_io;
    int do_ops;
    int do_mops;
    int do_iotime;
    int do_qops;
    int do_util;
    int do_backlog;
    int do_space;
    int do_inodes;

    struct disk *next;
} *disk_root = NULL;

static struct mountinfo *disk_mountinfo_root = NULL;

static struct disk *get_disk(unsigned long major, unsigned long minor, char *disk) {
    static char path_to_get_hw_sector_size[FILENAME_MAX + 1] = "";
    static char path_to_get_hw_sector_size_partitions[FILENAME_MAX + 1] = "";
    static char path_find_block_device[FILENAME_MAX + 1] = "";
    struct disk *d;

    // search for it in our RAM list.
    // this is sequential, but since we just walk through
    // and the number of disks / partitions in a system
    // should not be that many, it should be acceptable
    for(d = disk_root; d ; d = d->next)
        if(unlikely(d->major == major && d->minor == minor))
            break;

    // if we found it, return it
    if(likely(d))
        return d;

    // not found
    // create a new disk structure
    d = (struct disk *)mallocz(sizeof(struct disk));

    d->disk = strdupz(disk);
    d->major = major;
    d->minor = minor;
    d->type = DISK_TYPE_PHYSICAL; // Default type. Changed later if not correct.
    d->configured = 0;
    d->sector_size = 512; // the default, will be changed below
    d->next = NULL;

    // append it to the list
    if(!disk_root)
        disk_root = d;
    else {
        struct disk *last;
        for(last = disk_root; last->next ;last = last->next);
        last->next = d;
    }

    // ------------------------------------------------------------------------
    // find the type of the device

    char buffer[FILENAME_MAX + 1];

    // get the default path for finding info about the block device
    if(unlikely(!path_find_block_device[0])) {
        snprintfz(buffer, FILENAME_MAX, "%s%s", global_host_prefix, "/sys/dev/block/%lu:%lu/%s");
        snprintfz(path_find_block_device, FILENAME_MAX, "%s", config_get("plugin:proc:/proc/diskstats", "path to get block device infos", buffer));
    }

    // find if it is a partition
    // by checking if /sys/dev/block/MAJOR:MINOR/partition is readable.
    snprintfz(buffer, FILENAME_MAX, path_find_block_device, major, minor, "partition");
    if(access(buffer, R_OK) == 0) {
        d->type = DISK_TYPE_PARTITION;
    } else {
        // find if it is a container
        // by checking if /sys/dev/block/MAJOR:MINOR/slaves has entries
        snprintfz(buffer, FILENAME_MAX, path_find_block_device, major, minor, "slaves/");
        DIR *dirp = opendir(buffer);    
        if (dirp != NULL) {
            struct dirent *dp;
            while( (dp = readdir(dirp)) ) {
                // . and .. are also files in empty folders.
                if(strcmp(dp->d_name, ".") == 0 || strcmp(dp->d_name, "..") == 0) {
                    continue;
                }

                d->type = DISK_TYPE_CONTAINER;

                // Stop the loop after we found one file.
                break;
            }
            if(closedir(dirp) == -1)
                error("Unable to close dir %s", buffer);
        }
    }

    // ------------------------------------------------------------------------
    // check if we can find its mount point

    // mountinfo_find() can be called with NULL disk_mountinfo_root
    struct mountinfo *mi = mountinfo_find(disk_mountinfo_root, d->major, d->minor);
    if(unlikely(!mi)) {
        // mountinfo_free() can be called with NULL disk_mountinfo_root
        mountinfo_free(disk_mountinfo_root);

        // re-read mountinfo in case something changed
        disk_mountinfo_root = mountinfo_read();

        // search again for this disk
        mi = mountinfo_find(disk_mountinfo_root, d->major, d->minor);
    }

    if(mi)
        d->mount_point = strdupz(mi->mount_point);
        // no need to check for NULL
    else
        d->mount_point = NULL;

    // ------------------------------------------------------------------------
    // find the disk sector size

    if(!path_to_get_hw_sector_size[0]) {
        snprintfz(buffer, FILENAME_MAX, "%s%s", global_host_prefix, "/sys/block/%s/queue/hw_sector_size");
        snprintfz(path_to_get_hw_sector_size, FILENAME_MAX, "%s", config_get("plugin:proc:/proc/diskstats", "path to get h/w sector size", buffer));
    }
    if(!path_to_get_hw_sector_size_partitions[0]) {
        snprintfz(buffer, FILENAME_MAX, "%s%s", global_host_prefix, "/sys/dev/block/%lu:%lu/subsystem/%s/../queue/hw_sector_size");
        snprintfz(path_to_get_hw_sector_size_partitions, FILENAME_MAX, "%s", config_get("plugin:proc:/proc/diskstats", "path to get h/w sector size for partitions", buffer));
    }

    {
        char tf[FILENAME_MAX + 1], *t;
        strncpyz(tf, d->disk, FILENAME_MAX);

        // replace all / with !
        for(t = tf; *t ;t++)
            if(*t == '/') *t = '!';

        if(d->type == DISK_TYPE_PARTITION)
            snprintfz(buffer, FILENAME_MAX, path_to_get_hw_sector_size_partitions, d->major, d->minor, tf);
        else
            snprintfz(buffer, FILENAME_MAX, path_to_get_hw_sector_size, tf);

        FILE *fpss = fopen(buffer, "r");
        if(fpss) {
            char buffer2[1024 + 1];
            char *tmp = fgets(buffer2, 1024, fpss);

            if(tmp) {
                d->sector_size = atoi(tmp);
                if(d->sector_size <= 0) {
                    error("Invalid sector size %d for device %s in %s. Assuming 512.", d->sector_size, d->disk, buffer);
                    d->sector_size = 512;
                }
            }
            else error("Cannot read data for sector size for device %s from %s. Assuming 512.", d->disk, buffer);

            fclose(fpss);
        }
        else error("Cannot read sector size for device %s from %s. Assuming 512.", d->disk, buffer);
    }

    return d;
}

static inline int select_positive_option(int option1, int option2) {
    if(option1 == CONFIG_ONDEMAND_YES || option2 == CONFIG_ONDEMAND_YES)
        return CONFIG_ONDEMAND_YES;
    else if(option1 == CONFIG_ONDEMAND_ONDEMAND || option2 == CONFIG_ONDEMAND_ONDEMAND)
        return CONFIG_ONDEMAND_ONDEMAND;

    return CONFIG_ONDEMAND_NO;
}

int do_proc_diskstats(int update_every, unsigned long long dt) {
    static procfile *ff = NULL;
    static struct statvfs buff_statvfs;
    static struct stat buff_stat;
    static int  global_enable_new_disks_detected_at_runtime = CONFIG_ONDEMAND_YES,
                global_enable_performance_for_physical_disks = CONFIG_ONDEMAND_ONDEMAND,
                global_enable_performance_for_virtual_disks = CONFIG_ONDEMAND_NO,
                global_enable_performance_for_partitions = CONFIG_ONDEMAND_NO,
                global_enable_performance_for_mountpoints = CONFIG_ONDEMAND_NO,
                global_enable_performance_for_virtual_mountpoints = CONFIG_ONDEMAND_ONDEMAND,
                global_enable_space_for_mountpoints = CONFIG_ONDEMAND_ONDEMAND,
                global_do_io = CONFIG_ONDEMAND_ONDEMAND,
                global_do_ops = CONFIG_ONDEMAND_ONDEMAND,
                global_do_mops = CONFIG_ONDEMAND_ONDEMAND,
                global_do_iotime = CONFIG_ONDEMAND_ONDEMAND,
                global_do_qops = CONFIG_ONDEMAND_ONDEMAND,
                global_do_util = CONFIG_ONDEMAND_ONDEMAND,
                global_do_backlog = CONFIG_ONDEMAND_ONDEMAND,
                global_do_space = CONFIG_ONDEMAND_ONDEMAND,
                global_do_inodes = CONFIG_ONDEMAND_ONDEMAND,
                globals_initialized = 0;

    if(unlikely(!globals_initialized)) {
        global_enable_new_disks_detected_at_runtime = config_get_boolean("plugin:proc:/proc/diskstats", "enable new disks detected at runtime", global_enable_new_disks_detected_at_runtime);

        global_enable_performance_for_physical_disks = config_get_boolean_ondemand("plugin:proc:/proc/diskstats", "performance metrics for physical disks", global_enable_performance_for_physical_disks);
        global_enable_performance_for_virtual_disks = config_get_boolean_ondemand("plugin:proc:/proc/diskstats", "performance metrics for virtual disks", global_enable_performance_for_virtual_disks);
        global_enable_performance_for_partitions = config_get_boolean_ondemand("plugin:proc:/proc/diskstats", "performance metrics for partitions", global_enable_performance_for_partitions);
        global_enable_performance_for_mountpoints = config_get_boolean_ondemand("plugin:proc:/proc/diskstats", "performance metrics for mounted filesystems", global_enable_performance_for_mountpoints);
        global_enable_performance_for_virtual_mountpoints = config_get_boolean_ondemand("plugin:proc:/proc/diskstats", "performance metrics for mounted virtual disks", global_enable_performance_for_virtual_mountpoints);
        global_enable_space_for_mountpoints = config_get_boolean_ondemand("plugin:proc:/proc/diskstats", "space metrics for mounted filesystems", global_enable_space_for_mountpoints);

        global_do_io      = config_get_boolean_ondemand("plugin:proc:/proc/diskstats", "bandwidth for all disks", global_do_io);
        global_do_ops     = config_get_boolean_ondemand("plugin:proc:/proc/diskstats", "operations for all disks", global_do_ops);
        global_do_mops    = config_get_boolean_ondemand("plugin:proc:/proc/diskstats", "merged operations for all disks", global_do_mops);
        global_do_iotime  = config_get_boolean_ondemand("plugin:proc:/proc/diskstats", "i/o time for all disks", global_do_iotime);
        global_do_qops    = config_get_boolean_ondemand("plugin:proc:/proc/diskstats", "queued operations for all disks", global_do_qops);
        global_do_util    = config_get_boolean_ondemand("plugin:proc:/proc/diskstats", "utilization percentage for all disks", global_do_util);
        global_do_backlog = config_get_boolean_ondemand("plugin:proc:/proc/diskstats", "backlog for all disks", global_do_backlog);
        global_do_space   = config_get_boolean_ondemand("plugin:proc:/proc/diskstats", "space usage for all disks", global_do_space);
        global_do_inodes  = config_get_boolean_ondemand("plugin:proc:/proc/diskstats", "inodes usage for all disks", global_do_inodes);

        globals_initialized = 1;
    }

    if(!ff) {
        char filename[FILENAME_MAX + 1];
        snprintfz(filename, FILENAME_MAX, "%s%s", global_host_prefix, "/proc/diskstats");
        ff = procfile_open(config_get("plugin:proc:/proc/diskstats", "filename to monitor", filename), " \t", PROCFILE_FLAG_DEFAULT);
    }
    if(!ff) return 1;

    ff = procfile_readall(ff);
    if(!ff) return 0; // we return 0, so that we will retry to open it next time

    uint32_t lines = procfile_lines(ff), l;
    uint32_t words;

    for(l = 0; l < lines ;l++) {
        // --------------------------------------------------------------------------
        // Read parameters

        char *disk;
        unsigned long long  major = 0, minor = 0,
                            reads = 0,  mreads = 0,  readsectors = 0,  readms = 0,
                            writes = 0, mwrites = 0, writesectors = 0, writems = 0,
                            queued_ios = 0, busy_ms = 0, backlog_ms = 0,
                            space_avail = 0, space_avail_root = 0, space_used = 0,
                            inodes_avail = 0, inodes_avail_root = 0, inodes_used = 0;

        unsigned long long  last_reads = 0,  last_readsectors = 0,  last_readms = 0,
                            last_writes = 0, last_writesectors = 0, last_writems = 0,
                            last_busy_ms = 0;

        words = procfile_linewords(ff, l);
        if(words < 14) continue;

        major           = strtoull(procfile_lineword(ff, l, 0), NULL, 10);
        minor           = strtoull(procfile_lineword(ff, l, 1), NULL, 10);
        disk            = procfile_lineword(ff, l, 2);

        // # of reads completed # of writes completed
        // This is the total number of reads or writes completed successfully.
        reads           = strtoull(procfile_lineword(ff, l, 3), NULL, 10);  // rd_ios
        writes          = strtoull(procfile_lineword(ff, l, 7), NULL, 10);  // wr_ios

        // # of reads merged # of writes merged
        // Reads and writes which are adjacent to each other may be merged for
        // efficiency.  Thus two 4K reads may become one 8K read before it is
        // ultimately handed to the disk, and so it will be counted (and queued)
        mreads          = strtoull(procfile_lineword(ff, l, 4), NULL, 10);  // rd_merges_or_rd_sec
        mwrites         = strtoull(procfile_lineword(ff, l, 8), NULL, 10);  // wr_merges

        // # of sectors read # of sectors written
        // This is the total number of sectors read or written successfully.
        readsectors     = strtoull(procfile_lineword(ff, l, 5), NULL, 10);  // rd_sec_or_wr_ios
        writesectors    = strtoull(procfile_lineword(ff, l, 9), NULL, 10);  // wr_sec

        // # of milliseconds spent reading # of milliseconds spent writing
        // This is the total number of milliseconds spent by all reads or writes (as
        // measured from __make_request() to end_that_request_last()).
        readms          = strtoull(procfile_lineword(ff, l, 6), NULL, 10);  // rd_ticks_or_wr_sec
        writems         = strtoull(procfile_lineword(ff, l, 10), NULL, 10); // wr_ticks

        // # of I/Os currently in progress
        // The only field that should go to zero. Incremented as requests are
        // given to appropriate struct request_queue and decremented as they finish.
        queued_ios      = strtoull(procfile_lineword(ff, l, 11), NULL, 10); // ios_pgr

        // # of milliseconds spent doing I/Os
        // This field increases so long as field queued_ios is nonzero.
        busy_ms         = strtoull(procfile_lineword(ff, l, 12), NULL, 10); // tot_ticks

        // weighted # of milliseconds spent doing I/Os
        // This field is incremented at each I/O start, I/O completion, I/O
        // merge, or read of these stats by the number of I/Os in progress
        // (field queued_ios) times the number of milliseconds spent doing I/O since the
        // last update of this field.  This can provide an easy measure of both
        // I/O completion time and the backlog that may be accumulating.
        backlog_ms      = strtoull(procfile_lineword(ff, l, 13), NULL, 10); // rq_ticks


        // --------------------------------------------------------------------------
        // remove slashes from disk names
        char *s;
        for(s = disk; *s ;s++)
            if(*s == '/') *s = '_';

        // --------------------------------------------------------------------------
        // get a disk structure for the disk

        struct disk *d = get_disk(major, minor, disk);


        // --------------------------------------------------------------------------
        // Set its family based on mount point

        char *family = d->mount_point;
        if(!family) family = disk;


        // --------------------------------------------------------------------------
        // Check the configuration for the device

        if(unlikely(!d->configured)) {
            char var_name[4096 + 1];
            snprintfz(var_name, 4096, "plugin:proc:/proc/diskstats:%s", disk);

            int def_enable = config_get_boolean_ondemand(var_name, "enable", global_enable_new_disks_detected_at_runtime);
            if(def_enable == CONFIG_ONDEMAND_NO) {
                // the user does not want any metrics for this disk
                d->do_io = CONFIG_ONDEMAND_NO;
                d->do_ops = CONFIG_ONDEMAND_NO;
                d->do_mops = CONFIG_ONDEMAND_NO;
                d->do_iotime = CONFIG_ONDEMAND_NO;
                d->do_qops = CONFIG_ONDEMAND_NO;
                d->do_util = CONFIG_ONDEMAND_NO;
                d->do_backlog = CONFIG_ONDEMAND_NO;
                d->do_space = CONFIG_ONDEMAND_NO;
                d->do_inodes = CONFIG_ONDEMAND_NO;
            }
            else {
                // this disk is enabled
                // check its direct settings

                int def_performance = CONFIG_ONDEMAND_ONDEMAND;
                int def_space = (d->mount_point)?CONFIG_ONDEMAND_ONDEMAND:CONFIG_ONDEMAND_NO;

                // since this is 'on demand' we can figure the performance settings
                // based on the type of disk

                switch(d->type) {
                    case DISK_TYPE_PHYSICAL:
                        def_performance = global_enable_performance_for_physical_disks;
                        break;

                    case DISK_TYPE_PARTITION:
                        def_performance = global_enable_performance_for_partitions;
                        break;

                    case DISK_TYPE_CONTAINER:
                        def_performance = global_enable_performance_for_virtual_disks;

                        if(d->mount_point)
                            def_performance = select_positive_option(def_performance, global_enable_performance_for_virtual_mountpoints);

                        break;
                }

                if(d->mount_point)
                    def_performance = select_positive_option(def_performance, global_enable_performance_for_mountpoints);

                // ------------------------------------------------------------
                // now we have def_performance and def_space
                // to work further

                // def_performance
                // check the user configuration (this will also show our 'on demand' decision)
                def_performance = config_get_boolean_ondemand(var_name, "enable performance metrics", def_performance);

                int ddo_io = CONFIG_ONDEMAND_NO,
                    ddo_ops = CONFIG_ONDEMAND_NO,
                    ddo_mops = CONFIG_ONDEMAND_NO,
                    ddo_iotime = CONFIG_ONDEMAND_NO,
                    ddo_qops = CONFIG_ONDEMAND_NO,
                    ddo_util = CONFIG_ONDEMAND_NO,
                    ddo_backlog = CONFIG_ONDEMAND_NO;

                // we enable individual performance charts only when def_performance is not disabled
                if(def_performance != CONFIG_ONDEMAND_NO) {
                    ddo_io = global_do_io,
                    ddo_ops = global_do_ops,
                    ddo_mops = global_do_mops,
                    ddo_iotime = global_do_iotime,
                    ddo_qops = global_do_qops,
                    ddo_util = global_do_util,
                    ddo_backlog = global_do_backlog;
                }

                d->do_io      = config_get_boolean_ondemand(var_name, "bandwidth", ddo_io);
                d->do_ops     = config_get_boolean_ondemand(var_name, "operations", ddo_ops);
                d->do_mops    = config_get_boolean_ondemand(var_name, "merged operations", ddo_mops);
                d->do_iotime  = config_get_boolean_ondemand(var_name, "i/o time", ddo_iotime);
                d->do_qops    = config_get_boolean_ondemand(var_name, "queued operations", ddo_qops);
                d->do_util    = config_get_boolean_ondemand(var_name, "utilization percentage", ddo_util);
                d->do_backlog = config_get_boolean_ondemand(var_name, "backlog", ddo_backlog);

                // def_space
                if(d->mount_point) {
                    // check the user configuration (this will also show our 'on demand' decision)
                    def_space = config_get_boolean_ondemand(var_name, "enable space metrics", def_space);

                    int ddo_space = def_space,
                        ddo_inodes = def_space;

                    d->do_space = config_get_boolean_ondemand(var_name, "space usage", ddo_space);
                    d->do_inodes = config_get_boolean_ondemand(var_name, "inodes usage", ddo_inodes);
                }
                else {
                    // don't show settings for this disk
                    d->do_space = CONFIG_ONDEMAND_NO;
                    d->do_inodes = CONFIG_ONDEMAND_NO;
                }
            }

            d->configured = 1;
        }

        RRDSET *st;

        // --------------------------------------------------------------------------
        // Do performance metrics

        if(d->do_io == CONFIG_ONDEMAND_YES || (d->do_io == CONFIG_ONDEMAND_ONDEMAND && (readsectors || writesectors))) {
            d->do_io = CONFIG_ONDEMAND_YES;

            st = rrdset_find_bytype(RRD_TYPE_DISK, disk);
            if(!st) {
                st = rrdset_create(RRD_TYPE_DISK, disk, NULL, family, "disk.io", "Disk I/O Bandwidth", "kilobytes/s", 2000, update_every, RRDSET_TYPE_AREA);

                rrddim_add(st, "reads", NULL, d->sector_size, 1024, RRDDIM_INCREMENTAL);
                rrddim_add(st, "writes", NULL, d->sector_size * -1, 1024, RRDDIM_INCREMENTAL);
            }
            else rrdset_next_usec(st, dt);

            last_readsectors  = rrddim_set(st, "reads", readsectors);
            last_writesectors = rrddim_set(st, "writes", writesectors);
            rrdset_done(st);
        }

        // --------------------------------------------------------------------

        if(d->do_ops == CONFIG_ONDEMAND_YES || (d->do_ops == CONFIG_ONDEMAND_ONDEMAND && (reads || writes))) {
            d->do_ops = CONFIG_ONDEMAND_YES;

            st = rrdset_find_bytype("disk_ops", disk);
            if(!st) {
                st = rrdset_create("disk_ops", disk, NULL, family, "disk.ops", "Disk Completed I/O Operations", "operations/s", 2001, update_every, RRDSET_TYPE_LINE);
                st->isdetail = 1;

                rrddim_add(st, "reads", NULL, 1, 1, RRDDIM_INCREMENTAL);
                rrddim_add(st, "writes", NULL, -1, 1, RRDDIM_INCREMENTAL);
            }
            else rrdset_next_usec(st, dt);

            last_reads  = rrddim_set(st, "reads", reads);
            last_writes = rrddim_set(st, "writes", writes);
            rrdset_done(st);
        }

        // --------------------------------------------------------------------

        if(d->do_qops == CONFIG_ONDEMAND_YES || (d->do_qops == CONFIG_ONDEMAND_ONDEMAND && queued_ios)) {
            d->do_qops = CONFIG_ONDEMAND_YES;

            st = rrdset_find_bytype("disk_qops", disk);
            if(!st) {
                st = rrdset_create("disk_qops", disk, NULL, family, "disk.qops", "Disk Current I/O Operations", "operations", 2002, update_every, RRDSET_TYPE_LINE);
                st->isdetail = 1;

                rrddim_add(st, "operations", NULL, 1, 1, RRDDIM_ABSOLUTE);
            }
            else rrdset_next_usec(st, dt);

            rrddim_set(st, "operations", queued_ios);
            rrdset_done(st);
        }

        // --------------------------------------------------------------------

        if(d->do_backlog == CONFIG_ONDEMAND_YES || (d->do_backlog == CONFIG_ONDEMAND_ONDEMAND && backlog_ms)) {
            d->do_backlog = CONFIG_ONDEMAND_YES;

            st = rrdset_find_bytype("disk_backlog", disk);
            if(!st) {
                st = rrdset_create("disk_backlog", disk, NULL, family, "disk.backlog", "Disk Backlog", "backlog (ms)", 2003, update_every, RRDSET_TYPE_AREA);
                st->isdetail = 1;

                rrddim_add(st, "backlog", NULL, 1, 10, RRDDIM_INCREMENTAL);
            }
            else rrdset_next_usec(st, dt);

            rrddim_set(st, "backlog", backlog_ms);
            rrdset_done(st);
        }

        // --------------------------------------------------------------------

        if(d->do_util == CONFIG_ONDEMAND_YES || (d->do_util == CONFIG_ONDEMAND_ONDEMAND && busy_ms)) {
            d->do_util = CONFIG_ONDEMAND_YES;

            st = rrdset_find_bytype("disk_util", disk);
            if(!st) {
                st = rrdset_create("disk_util", disk, NULL, family, "disk.util", "Disk Utilization Time", "% of time working", 2004, update_every, RRDSET_TYPE_AREA);
                st->isdetail = 1;

                rrddim_add(st, "utilization", NULL, 1, 10, RRDDIM_INCREMENTAL);
            }
            else rrdset_next_usec(st, dt);

            last_busy_ms = rrddim_set(st, "utilization", busy_ms);
            rrdset_done(st);
        }

        // --------------------------------------------------------------------

        if(d->do_mops == CONFIG_ONDEMAND_YES || (d->do_mops == CONFIG_ONDEMAND_ONDEMAND && (mreads || mwrites))) {
            d->do_mops = CONFIG_ONDEMAND_YES;

            st = rrdset_find_bytype("disk_mops", disk);
            if(!st) {
                st = rrdset_create("disk_mops", disk, NULL, family, "disk.mops", "Disk Merged Operations", "merged operations/s", 2021, update_every, RRDSET_TYPE_LINE);
                st->isdetail = 1;

                rrddim_add(st, "reads", NULL, 1, 1, RRDDIM_INCREMENTAL);
                rrddim_add(st, "writes", NULL, -1, 1, RRDDIM_INCREMENTAL);
            }
            else rrdset_next_usec(st, dt);

            rrddim_set(st, "reads", mreads);
            rrddim_set(st, "writes", mwrites);
            rrdset_done(st);
        }

        // --------------------------------------------------------------------

        if(d->do_iotime == CONFIG_ONDEMAND_YES || (d->do_iotime == CONFIG_ONDEMAND_ONDEMAND && (readms || writems))) {
            d->do_iotime = CONFIG_ONDEMAND_YES;

            st = rrdset_find_bytype("disk_iotime", disk);
            if(!st) {
                st = rrdset_create("disk_iotime", disk, NULL, family, "disk.iotime", "Disk Total I/O Time", "milliseconds/s", 2022, update_every, RRDSET_TYPE_LINE);
                st->isdetail = 1;

                rrddim_add(st, "reads", NULL, 1, 1, RRDDIM_INCREMENTAL);
                rrddim_add(st, "writes", NULL, -1, 1, RRDDIM_INCREMENTAL);
            }
            else rrdset_next_usec(st, dt);

            last_readms  = rrddim_set(st, "reads", readms);
            last_writems = rrddim_set(st, "writes", writems);
            rrdset_done(st);
        }

        // --------------------------------------------------------------------
        // calculate differential charts
        // only if this is not the first time we run

        if(dt) {
            if( (d->do_iotime == CONFIG_ONDEMAND_YES || (d->do_iotime == CONFIG_ONDEMAND_ONDEMAND && (readms || writems))) &&
                (d->do_ops    == CONFIG_ONDEMAND_YES || (d->do_ops    == CONFIG_ONDEMAND_ONDEMAND && (reads || writes)))) {
                st = rrdset_find_bytype("disk_await", disk);
                if(!st) {
                    st = rrdset_create("disk_await", disk, NULL, family, "disk.await", "Average Completed I/O Operation Time", "ms per operation", 2005, update_every, RRDSET_TYPE_LINE);
                    st->isdetail = 1;

                    rrddim_add(st, "reads", NULL, 1, 1, RRDDIM_ABSOLUTE);
                    rrddim_add(st, "writes", NULL, -1, 1, RRDDIM_ABSOLUTE);
                }
                else rrdset_next_usec(st, dt);

                rrddim_set(st, "reads", (reads - last_reads) ? (readms - last_readms) / (reads - last_reads) : 0);
                rrddim_set(st, "writes", (writes - last_writes) ? (writems - last_writems) / (writes - last_writes) : 0);
                rrdset_done(st);
            }

            if( (d->do_io  == CONFIG_ONDEMAND_YES || (d->do_io  == CONFIG_ONDEMAND_ONDEMAND && (readsectors || writesectors))) &&
                (d->do_ops == CONFIG_ONDEMAND_YES || (d->do_ops == CONFIG_ONDEMAND_ONDEMAND && (reads || writes)))) {
                st = rrdset_find_bytype("disk_avgsz", disk);
                if(!st) {
                    st = rrdset_create("disk_avgsz", disk, NULL, family, "disk.avgsz", "Average Completed I/O Operation Bandwidth", "kilobytes per operation", 2006, update_every, RRDSET_TYPE_AREA);
                    st->isdetail = 1;

                    rrddim_add(st, "reads", NULL, d->sector_size, 1024, RRDDIM_ABSOLUTE);
                    rrddim_add(st, "writes", NULL, d->sector_size * -1, 1024, RRDDIM_ABSOLUTE);
                }
                else rrdset_next_usec(st, dt);

                rrddim_set(st, "reads", (reads - last_reads) ? (readsectors - last_readsectors) / (reads - last_reads) : 0);
                rrddim_set(st, "writes", (writes - last_writes) ? (writesectors - last_writesectors) / (writes - last_writes) : 0);
                rrdset_done(st);
            }

            if( (d->do_util == CONFIG_ONDEMAND_YES || (d->do_util == CONFIG_ONDEMAND_ONDEMAND && busy_ms)) &&
                (d->do_ops  == CONFIG_ONDEMAND_YES || (d->do_ops  == CONFIG_ONDEMAND_ONDEMAND && (reads || writes)))) {
                st = rrdset_find_bytype("disk_svctm", disk);
                if(!st) {
                    st = rrdset_create("disk_svctm", disk, NULL, family, "disk.svctm", "Average Service Time", "ms per operation", 2007, update_every, RRDSET_TYPE_LINE);
                    st->isdetail = 1;

                    rrddim_add(st, "svctm", NULL, 1, 1, RRDDIM_ABSOLUTE);
                }
                else rrdset_next_usec(st, dt);

                rrddim_set(st, "svctm", ((reads - last_reads) + (writes - last_writes)) ? (busy_ms - last_busy_ms) / ((reads - last_reads) + (writes - last_writes)) : 0);
                rrdset_done(st);
            }
        }

        // --------------------------------------------------------------------------
        // space metrics

        if(d->mount_point && (d->do_space || d->do_inodes) ) {
            // collect space metrics using statvfs

            if (statvfs(d->mount_point, &buff_statvfs) < 0)
                error("Failed statvfs() for '%s' (disk '%s')", d->mount_point, d->disk);
            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;

                inodes_avail = buff_statvfs.f_favail;
                inodes_avail_root = buff_statvfs.f_ffree - buff_statvfs.f_favail;
                inodes_used = buff_statvfs.f_files - buff_statvfs.f_ffree;

                // verify we collected the metrics for the right disk.
                // if not the mountpoint has changed.

                if(stat(d->mount_point, &buff_stat) == -1)
                    error("Failed to stat() for '%s' (disk '%s')", d->mount_point, d->disk);
                else {
                    if(major(buff_stat.st_dev) == major && minor(buff_stat.st_dev) == minor) {

                        // --------------------------------------------------------------------------

                        if(d->do_space == CONFIG_ONDEMAND_YES || (d->do_space == CONFIG_ONDEMAND_ONDEMAND && (space_avail || space_avail_root || space_used))) {
                            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, 1024*1024*1024, RRDDIM_ABSOLUTE);
                                rrddim_add(st, "used" , NULL, 1, 1024*1024*1024, RRDDIM_ABSOLUTE);
                                rrddim_add(st, "reserved_for_root", "reserved for root", 1, 1024*1024*1024, RRDDIM_ABSOLUTE);
                            }
                            else rrdset_next_usec(st, dt);

                            rrddim_set(st, "avail", space_avail);
                            rrddim_set(st, "used", space_used);
                            rrddim_set(st, "reserved_for_root", space_avail_root);
                            rrdset_done(st);
                        }

                        // --------------------------------------------------------------------------

                        if(d->do_inodes == CONFIG_ONDEMAND_YES || (d->do_inodes == CONFIG_ONDEMAND_ONDEMAND && (inodes_avail || inodes_avail_root || inodes_used))) {
                            st = rrdset_find_bytype("disk_inodes", disk);
                            if(!st) {
                                st = rrdset_create("disk_inodes", disk, NULL, family, "disk.inodes", "Disk Inodes Usage", "Inodes", 2024, update_every, RRDSET_TYPE_STACKED);
                                st->isdetail = 1;

                                rrddim_add(st, "avail", NULL, 1, 1, RRDDIM_ABSOLUTE);
                                rrddim_add(st, "used" , NULL, 1, 1, RRDDIM_ABSOLUTE);
                                rrddim_add(st, "reserved_for_root", "reserved for root", 1, 1, RRDDIM_ABSOLUTE);
                            }
                            else rrdset_next_usec(st, dt);

                            rrddim_set(st, "avail", inodes_avail);
                            rrddim_set(st, "used", inodes_used);
                            rrddim_set(st, "reserved_for_root", inodes_avail_root);
                            rrdset_done(st);
                        }
                    }
                }
            }
        }
    }

    return 0;
}