kernel - Fix bogus compiler warning

[dragonfly.git] / sbin / hammer / cmd_cleanup.c

/*
 * Copyright (c) 2008 The DragonFly Project.  All rights reserved.
 *
 * This code is derived from software contributed to The DragonFly Project
 * by Matthew Dillon <dillon@backplane.com>
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name of The DragonFly Project nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific, prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $DragonFly: src/sbin/hammer/cmd_cleanup.c,v 1.6 2008/10/07 22:28:41 thomas Exp $
 */
/*
 * Clean up specific HAMMER filesystems or all HAMMER filesystems.
 *
 * If no filesystems are specified any HAMMER- or null-mounted hammer PFS's
 * are cleaned.
 *
 * Each HAMMER filesystem may contain a configuration file.  If no
 * configuration file is present one will be created with the following
 * defaults:
 *
 *      snapshots 1d 60d        (0d 0d for /tmp, /var/tmp, /usr/obj)
 *      prune     1d 5m
 *      rebalance 1d 5m
 *      reblock   1d 5m
 *      recopy    30d 10m
 *
 * All hammer commands create and maintain cycle files in the snapshots
 * directory.
 *
 * For HAMMER version 2- the configuration file is a named 'config' in
 * the snapshots directory, which defaults to <pfs>/snapshots.
 * For HAMMER version 3+ the configuration file is saved in filesystem
 * meta-data. The snapshots directory defaults to /var/hammer/<pfs>
 * (/var/hammer/root for root mount).
 */

#include "hammer.h"

struct didpfs {
        struct didpfs *next;
        uuid_t          uuid;
};

static void do_cleanup(const char *path);
static void config_init(const char *path, struct hammer_ioc_config *config);
static void migrate_config(FILE *fp, struct hammer_ioc_config *config);
static void migrate_snapshots(int fd, const char *snapshots_path);
static void migrate_one_snapshot(int fd, const char *fpath,
                        struct hammer_ioc_snapshot *snapshot);
static int strtosecs(char *ptr);
static const char *dividing_slash(const char *path);
static int check_period(const char *snapshots_path, const char *cmd, int arg1,
                        time_t *savep);
static void save_period(const char *snapshots_path, const char *cmd,
                        time_t savet);
static int check_softlinks(int fd, int new_config, const char *snapshots_path);
static void cleanup_softlinks(int fd, int new_config,
                        const char *snapshots_path, int arg2, char *arg3);
static void delete_snapshots(int fd, struct hammer_ioc_snapshot *dsnapshot);
static int check_expired(const char *fpath, int arg2);

static int create_snapshot(const char *path, const char *snapshots_path);
static int cleanup_rebalance(const char *path, const char *snapshots_path,
                        int arg1, int arg2);
static int cleanup_prune(const char *path, const char *snapshots_path,
                        int arg1, int arg2, int snapshots_disabled);
static int cleanup_reblock(const char *path, const char *snapshots_path,
                        int arg1, int arg2);
static int cleanup_recopy(const char *path, const char *snapshots_path,
                        int arg1, int arg2);

static void runcmd(int *resp, const char *ctl, ...);

/*
 * WARNING: Do not make the SNAPSHOTS_BASE "/var/snapshots" because
 * it will interfere with the older HAMMER VERS < 3 snapshots directory
 * for the /var PFS.
 */
#define SNAPSHOTS_BASE  "/var/hammer"   /* HAMMER VERS >= 3 */
#define WS      " \t\r\n"

struct didpfs *FirstPFS;

void
hammer_cmd_cleanup(char **av, int ac)
{
        char *fstype, *fs, *path;
        struct statfs *stfsbuf;
        int mntsize, i;

        tzset();
        if (ac == 0) {
                mntsize = getmntinfo(&stfsbuf, MNT_NOWAIT);
                if (mntsize > 0) {
                        for (i=0; i < mntsize; i++) {
                                /*
                                 * We will cleanup in the case fstype is hammer.
                                 * If we have null-mounted PFS, we check the
                                 * mount source. If it looks like a PFS, we
                                 * proceed to cleanup also.
                                 */
                                fstype = stfsbuf[i].f_fstypename;
                                fs = stfsbuf[i].f_mntfromname;
                                if ((strcmp(fstype, "hammer") == 0) ||
                                    ((strcmp(fstype, "null") == 0) &&
                                     (strstr(fs, "/@@0x") != NULL ||
                                      strstr(fs, "/@@-1") != NULL))) {
                                        path = stfsbuf[i].f_mntonname;
                                        do_cleanup(path);
                                }
                        }
                }

        } else {
                while (ac) {
                        do_cleanup(*av);
                        --ac;
                        ++av;
                }
        }
}

static
void
do_cleanup(const char *path)
{
        struct hammer_ioc_pseudofs_rw pfs;
        struct hammer_ioc_config config;
        struct hammer_ioc_version version;
        union hammer_ioc_mrecord_any mrec_tmp;
        char *snapshots_path = NULL;
        char *config_path;
        struct stat st;
        char *cmd;
        char *ptr;
        int arg1;
        int arg2;
        char *arg3;
        time_t savet;
        char buf[256];
        char *cbase;
        char *cptr;
        FILE *fp = NULL;
        struct didpfs *didpfs;
        int snapshots_disabled = 0;
        int prune_warning = 0;
        int new_config = 0;
        int snapshots_from_pfs = 0;
        int fd;
        int r;
        int found_rebal = 0;

        bzero(&pfs, sizeof(pfs));
        bzero(&mrec_tmp, sizeof(mrec_tmp));
        pfs.ondisk = &mrec_tmp.pfs.pfsd;
        pfs.bytes = sizeof(mrec_tmp.pfs.pfsd);
        pfs.pfs_id = -1;

        printf("cleanup %-20s -", path);
        fd = open(path, O_RDONLY);
        if (fd < 0) {
                printf(" unable to access directory: %s\n", strerror(errno));
                return;
        }
        if (ioctl(fd, HAMMERIOC_GET_PSEUDOFS, &pfs) < 0) {
                printf(" not a HAMMER filesystem: %s\n", strerror(errno));
                close(fd);
                return;
        }
        if (pfs.version != HAMMER_IOC_PSEUDOFS_VERSION) {
                printf(" unrecognized HAMMER version\n");
                close(fd);
                return;
        }
        bzero(&version, sizeof(version));
        if (ioctl(fd, HAMMERIOC_GET_VERSION, &version) < 0) {
                printf(" HAMMER filesystem but couldn't retrieve version!\n");
                close(fd);
                return;
        }

        bzero(&config, sizeof(config));
        if (version.cur_version >= 3) {
                if (ioctl(fd, HAMMERIOC_GET_CONFIG, &config) == 0 &&
                    config.head.error == 0) {
                        new_config = 1;
                }
        }

        /*
         * Make sure we have not already handled this PFS.  Several nullfs
         * mounts might alias the same PFS.
         */
        for (didpfs = FirstPFS; didpfs; didpfs = didpfs->next) {
                if (bcmp(&didpfs->uuid, &mrec_tmp.pfs.pfsd.unique_uuid, sizeof(uuid_t)) == 0) {
                        printf(" PFS #%d already handled\n", pfs.pfs_id);
                        close(fd);
                        return;
                }
        }
        didpfs = malloc(sizeof(*didpfs));
        didpfs->next = FirstPFS;
        FirstPFS = didpfs;
        didpfs->uuid = mrec_tmp.pfs.pfsd.unique_uuid;

        /*
         * Calculate the old snapshots directory for HAMMER VERSION < 3
         *
         * If the directory is explicitly specified in the PFS config
         * we flag it and will not migrate it later.
         */
        if (mrec_tmp.pfs.pfsd.snapshots[0] == '/') {
                asprintf(&snapshots_path, "%s", mrec_tmp.pfs.pfsd.snapshots);
                snapshots_from_pfs = 1;
        } else if (mrec_tmp.pfs.pfsd.snapshots[0]) {
                printf(" WARNING: pfs-slave's snapshots dir is not absolute\n");
                close(fd);
                return;
        } else if (mrec_tmp.pfs.pfsd.mirror_flags & HAMMER_PFSD_SLAVE) {
                if (version.cur_version < 3) {
                        printf(" WARNING: must configure snapshot dir for PFS slave\n");
                        printf("\tWe suggest <fs>/var/slaves/<name> where "
                               "<fs> is the base HAMMER fs\n");
                        printf("\tcontaining the slave\n");
                        close(fd);
                        return;
                }
        } else {
                asprintf(&snapshots_path,
                         "%s%ssnapshots", path, dividing_slash(path));
        }

        /*
         * Check for old-style config file
         */
        if (snapshots_path) {
                asprintf(&config_path, "%s/config", snapshots_path);
                fp = fopen(config_path, "r");
        }

        /*
         * Handle upgrades to hammer version 3, move the config
         * file into meta-data.
         *
         * For the old config read the file into the config structure,
         * we will parse it out of the config structure regardless.
         */
        if (version.cur_version >= 3) {
                if (fp) {
                        printf("(migrating) ");
                        fflush(stdout);
                        migrate_config(fp, &config);
                        migrate_snapshots(fd, snapshots_path);
                        fclose(fp);
                        if (ioctl(fd, HAMMERIOC_SET_CONFIG, &config) < 0) {
                                printf(" cannot init meta-data config!\n");
                                close(fd);
                                return;
                        }
                        remove(config_path);
                } else if (new_config == 0) {
                        config_init(path, &config);
                        if (ioctl(fd, HAMMERIOC_SET_CONFIG, &config) < 0) {
                                printf(" cannot init meta-data config!\n");
                                close(fd);
                                return;
                        }
                }
                new_config = 1;
        } else {
                /*
                 * Create missing snapshots directory for HAMMER VERSION < 3
                 */
                if (stat(snapshots_path, &st) < 0) {
                        if (mkdir(snapshots_path, 0755) != 0) {
                                free(snapshots_path);
                                printf(" unable to create snapshot dir \"%s\": %s\n",
                                        snapshots_path, strerror(errno));
                                close(fd);
                                return;
                        }
                }

                /*
                 *  Create missing config file for HAMMER VERSION < 3
                 */
                if (fp == NULL) {
                        config_init(path, &config);
                        fp = fopen(config_path, "w");
                        if (fp) {
                                fwrite(config.config.text, 1,
                                        strlen(config.config.text), fp);
                                fclose(fp);
                        }
                } else {
                        migrate_config(fp, &config);
                        fclose(fp);
                }
        }

        /*
         * If snapshots_from_pfs is not set we calculate the new snapshots
         * directory default (in /var) for HAMMER VERSION >= 3 and migrate
         * the old snapshots directory over.
         *
         * People who have set an explicit snapshots directory will have
         * to migrate the data manually into /var/hammer, or not bother at
         * all.  People running slaves may wish to migrate it and then
         * clear the snapshots specification in the PFS config for the
         * slave.
         */
        if (new_config && snapshots_from_pfs == 0) {
                char *npath;

                assert(path[0] == '/');
                if (strcmp(path, "/") == 0)
                        asprintf(&npath, "%s/root", SNAPSHOTS_BASE);
                else
                        asprintf(&npath, "%s/%s", SNAPSHOTS_BASE, path + 1);
                if (snapshots_path) {
                        if (stat(npath, &st) < 0 && errno == ENOENT) {
                                if (stat(snapshots_path, &st) < 0 && errno == ENOENT) {
                                        printf(" HAMMER UPGRADE: Creating snapshots\n"
                                               "\tCreating snapshots in %s\n",
                                               npath);
                                        runcmd(&r, "mkdir -p %s", npath);
                                } else {
                                        printf(" HAMMER UPGRADE: Moving snapshots\n"
                                               "\tMoving snapshots from %s to %s\n",
                                               snapshots_path, npath);
                                        runcmd(&r, "mkdir -p %s", npath);
                                        runcmd(&r, "cpdup %s %s", snapshots_path, npath);
                                        if (r != 0) {
                                    printf("Unable to move snapshots directory!\n");
                                    printf("Please fix this critical error.\n");
                                    printf("Aborting cleanup of %s\n", path);
                                                close(fd);
                                                return;
                                        }
                                        runcmd(&r, "rm -rf %s", snapshots_path);
                                }
                        }
                        free(snapshots_path);
                } else if (stat(npath, &st) < 0 && errno == ENOENT) {
                        runcmd(&r, "mkdir -p %s", npath);
                }
                snapshots_path = npath;
        }

        /*
         * Lock the PFS.  fd is the base directory of the mounted PFS.
         */
        if (flock(fd, LOCK_EX|LOCK_NB) == -1) {
                if (errno == EWOULDBLOCK)
                        printf(" PFS #%d locked by other process\n", pfs.pfs_id);
                else
                        printf(" can not lock %s: %s\n", config_path, strerror(errno));
                close(fd);
                return;
        }

        printf(" handle PFS #%d using %s\n", pfs.pfs_id, snapshots_path);

        /*
         * Process the config file
         */
        cbase = config.config.text;

        while ((cptr = strchr(cbase, '\n')) != NULL) {
                bcopy(cbase, buf, cptr - cbase);
                buf[cptr - cbase] = 0;
                cbase = cptr + 1;

                cmd = strtok(buf, WS);
                if (cmd == NULL || cmd[0] == '#')
                        continue;

                arg1 = 0;
                arg2 = 0;
                arg3 = NULL;
                if ((ptr = strtok(NULL, WS)) != NULL) {
                        arg1 = strtosecs(ptr);
                        if ((ptr = strtok(NULL, WS)) != NULL) {
                                arg2 = strtosecs(ptr);
                                arg3 = strtok(NULL, WS);
                        }
                }

                printf("%20s - ", cmd);
                fflush(stdout);

                r = 1;
                if (strcmp(cmd, "snapshots") == 0) {
                        if (arg1 == 0) {
                                if (arg2 &&
                                    check_softlinks(fd, new_config,
                                                    snapshots_path)) {
                                        printf("only removing old snapshots\n");
                                        prune_warning = 1;
                                        cleanup_softlinks(fd, new_config,
                                                          snapshots_path,
                                                          arg2, arg3);
                                } else {
                                        printf("disabled\n");
                                        snapshots_disabled = 1;
                                }
                        } else
                        if (check_period(snapshots_path, cmd, arg1, &savet)) {
                                printf("run\n");
                                cleanup_softlinks(fd, new_config,
                                                  snapshots_path,
                                                  arg2, arg3);
                                r = create_snapshot(path, snapshots_path);
                        } else {
                                printf("skip\n");
                        }
                } else if (arg1 == 0) {
                        /*
                         * The commands following this check can't handle
                         * a period of 0, so call the feature disabled and
                         * ignore the directive.
                         */
                        printf("disabled\n");
                } else if (strcmp(cmd, "prune") == 0) {
                        if (check_period(snapshots_path, cmd, arg1, &savet)) {
                                if (prune_warning) {
                                        printf("run - WARNING snapshot "
                                               "softlinks present "
                                               "but snapshots disabled\n");
                                } else {
                                        printf("run\n");
                                }
                                r = cleanup_prune(path, snapshots_path,
                                              arg1, arg2, snapshots_disabled);
                        } else {
                                printf("skip\n");
                        }
                } else if (strcmp(cmd, "rebalance") == 0) {
                        found_rebal = 1;
                        if (check_period(snapshots_path, cmd, arg1, &savet)) {
                                printf("run");
                                fflush(stdout);
                                if (VerboseOpt)
                                        printf("\n");
                                r = cleanup_rebalance(path, snapshots_path,
                                                arg1, arg2);
                        } else {
                                printf("skip\n");
                        }
                } else if (strcmp(cmd, "reblock") == 0) {
                        if (check_period(snapshots_path, cmd, arg1, &savet)) {
                                printf("run");
                                fflush(stdout);
                                if (VerboseOpt)
                                        printf("\n");
                                r = cleanup_reblock(path, snapshots_path,
                                                arg1, arg2);
                        } else {
                                printf("skip\n");
                        }
                } else if (strcmp(cmd, "recopy") == 0) {
                        if (check_period(snapshots_path, cmd, arg1, &savet)) {
                                printf("run");
                                fflush(stdout);
                                if (VerboseOpt)
                                        printf("\n");
                                r = cleanup_recopy(path, snapshots_path,
                                               arg1, arg2);
                        } else {
                                printf("skip\n");
                        }
                } else {
                        printf("unknown directive\n");
                        r = 1;
                }
                if (r == 0)
                        save_period(snapshots_path, cmd, savet);
        }

        /*
         * Add new rebalance feature if the config doesn't have it.
         * (old style config only).
         */
        if (new_config == 0 && found_rebal == 0) {
                if ((fp = fopen(config_path, "r+")) != NULL) {
                        fseek(fp, 0L, 2);
                        fprintf(fp, "rebalance 1d 5m\n");
                        fclose(fp);
                }
        }

        /*
         * Cleanup, and delay a little
         */
        close(fd);
        usleep(1000);
}

/*
 * Initialize new config data (new or old style)
 */
static void
config_init(const char *path, struct hammer_ioc_config *config)
{
        const char *snapshots;

        if (strcmp(path, "/tmp") == 0 ||
            strcmp(path, "/var/tmp") == 0 ||
            strcmp(path, "/usr/obj") == 0) {
                snapshots = "snapshots 0d 0d\n";
        } else {
                snapshots = "snapshots 1d 60d\n";
        }
        bzero(config->config.text, sizeof(config->config.text));
        snprintf(config->config.text, sizeof(config->config.text) - 1, "%s%s",
                snapshots,
                "prune     1d 5m\n"
                "rebalance 1d 5m\n"
                "reblock   1d 5m\n"
                "recopy    30d 10m\n");
}

/*
 * Migrate configuration data from the old snapshots/config
 * file to the new meta-data format.
 */
static void
migrate_config(FILE *fp, struct hammer_ioc_config *config)
{
        int n;

        n = fread(config->config.text, 1, sizeof(config->config.text) - 1, fp);
        if (n >= 0)
                bzero(config->config.text + n, sizeof(config->config.text) - n);
}

/*
 * Migrate snapshot softlinks in the snapshots directory to the
 * new meta-data format.  The softlinks are left intact, but
 * this way the pruning code won't lose track of them if you
 * happen to blow away the snapshots directory.
 */
static void
migrate_snapshots(int fd, const char *snapshots_path)
{
        struct hammer_ioc_snapshot snapshot;
        struct dirent *den;
        struct stat st;
        DIR *dir;
        char *fpath;

        bzero(&snapshot, sizeof(snapshot));

        if ((dir = opendir(snapshots_path)) != NULL) {
                while ((den = readdir(dir)) != NULL) {
                        if (den->d_name[0] == '.')
                                continue;
                        asprintf(&fpath, "%s/%s", snapshots_path, den->d_name);
                        if (lstat(fpath, &st) == 0 && S_ISLNK(st.st_mode)) {
                                migrate_one_snapshot(fd, fpath, &snapshot);
                        }
                        free(fpath);
                }
                closedir(dir);
        }
        migrate_one_snapshot(fd, NULL, &snapshot);

}

/*
 * Migrate a single snapshot.  If fpath is NULL the ioctl is flushed,
 * otherwise it is flushed when it fills up.
 */
static void
migrate_one_snapshot(int fd, const char *fpath,
                     struct hammer_ioc_snapshot *snapshot)
{
        if (fpath) {
                struct hammer_snapshot_data *snap;
                struct tm tm;
                time_t t;
                int year;
                int month;
                int day = 0;
                int hour = 0;
                int minute = 0;
                int r;
                char linkbuf[1024];
                const char *ptr;
                hammer_tid_t tid;

                t = (time_t)-1;
                tid = (hammer_tid_t)(int64_t)-1;

                ptr = fpath;
                while (*ptr && *ptr != '-' && *ptr != '.')
                        ++ptr;
                if (*ptr)
                        ++ptr;
                r = sscanf(ptr, "%4d%2d%2d-%2d%2d",
                           &year, &month, &day, &hour, &minute);

                if (r >= 3) {
                        bzero(&tm, sizeof(tm));
                        tm.tm_isdst = -1;
                        tm.tm_min = minute;
                        tm.tm_hour = hour;
                        tm.tm_mday = day;
                        tm.tm_mon = month - 1;
                        tm.tm_year = year - 1900;
                        t = mktime(&tm);
                }
                bzero(linkbuf, sizeof(linkbuf));
                if (readlink(fpath, linkbuf, sizeof(linkbuf) - 1) > 0 &&
                    (ptr = strrchr(linkbuf, '@')) != NULL &&
                    ptr > linkbuf && ptr[-1] == '@') {
                        tid = strtoull(ptr + 1, NULL, 16);
                }
                if (t != (time_t)-1 && tid != (hammer_tid_t)(int64_t)-1) {
                        snap = &snapshot->snaps[snapshot->count];
                        bzero(snap, sizeof(*snap));
                        snap->tid = tid;
                        snap->ts = (u_int64_t)t * 1000000ULL;
                        snprintf(snap->label, sizeof(snap->label),
                                 "migrated");
                        ++snapshot->count;
                }
        }

        if ((fpath == NULL && snapshot->count) ||
            snapshot->count == HAMMER_SNAPS_PER_IOCTL) {
                printf(" (%d snapshots)", snapshot->count);
again:
                if (ioctl(fd, HAMMERIOC_ADD_SNAPSHOT, snapshot) < 0) {
                        printf("    Ioctl to migrate snapshots failed: %s\n",
                               strerror(errno));
                } else if (snapshot->head.error == EALREADY) {
                        ++snapshot->index;
                        goto again;
                } else if (snapshot->head.error) {
                        printf("    Ioctl to migrate snapshots failed: %s\n",
                               strerror(snapshot->head.error));
                }
                printf("index %d\n", snapshot->index);
                snapshot->index = 0;
                snapshot->count = 0;
                snapshot->head.error = 0;
        }
}

static
int
strtosecs(char *ptr)
{
        int val;

        val = strtol(ptr, &ptr, 0);
        switch(*ptr) {
        case 'd':
                val *= 24;
                /* fall through */
        case 'h':
                val *= 60;
                /* fall through */
        case 'm':
                val *= 60;
                /* fall through */
        case 's':
                break;
        default:
                errx(1, "illegal suffix converting %s\n", ptr);
                break;
        }
        return(val);
}

static const char *
dividing_slash(const char *path)
{
        int len = strlen(path);
        if (len && path[len-1] == '/')
                return("");
        else
                return("/");
}

/*
 * Check whether the desired period has elapsed since the last successful
 * run.  The run may take a while and cross a boundary so we remember the
 * current time_t so we can save it later on.
 *
 * Periods in minutes, hours, or days are assumed to have been crossed
 * if the local time crosses a minute, hour, or day boundary regardless
 * of how close the last operation actually was.
 */
static int
check_period(const char *snapshots_path, const char *cmd, int arg1,
        time_t *savep)
{
        char *check_path;
        struct tm tp1;
        struct tm tp2;
        FILE *fp;
        time_t baset, lastt;
        char buf[256];

        time(savep);
        localtime_r(savep, &tp1);

        /*
         * Retrieve the start time of the last successful operation.
         */
        asprintf(&check_path, "%s/.%s.period", snapshots_path, cmd);
        fp = fopen(check_path, "r");
        free(check_path);
        if (fp == NULL)
                return(1);
        if (fgets(buf, sizeof(buf), fp) == NULL) {
                fclose(fp);
                return(1);
        }
        fclose(fp);

        lastt = strtol(buf, NULL, 0);
        localtime_r(&lastt, &tp2);

        /*
         * Normalize the times.  e.g. if asked to do something on a 1-day
         * interval the operation will be performed as soon as the day
         * turns over relative to the previous operation, even if the previous
         * operation ran a few seconds ago just before midnight.
         */
        if (arg1 % 60 == 0) {
                tp1.tm_sec = 0;
                tp2.tm_sec = 0;
        }
        if (arg1 % (60 * 60) == 0) {
                tp1.tm_min = 0;
                tp2.tm_min = 0;
        }
        if (arg1 % (24 * 60 * 60) == 0) {
                tp1.tm_hour = 0;
                tp2.tm_hour = 0;
        }

        baset = mktime(&tp1);
        lastt = mktime(&tp2);

#if 0
        printf("%lld vs %lld\n", (long long)(baset - lastt), (long long)arg1);
#endif

        if ((int)(baset - lastt) >= arg1)
                return(1);
        return(0);
}

/*
 * Store the start time of the last successful operation.
 */
static void
save_period(const char *snapshots_path, const char *cmd,
                        time_t savet)
{
        char *ocheck_path;
        char *ncheck_path;
        FILE *fp;

        asprintf(&ocheck_path, "%s/.%s.period", snapshots_path, cmd);
        asprintf(&ncheck_path, "%s/.%s.period.new", snapshots_path, cmd);
        fp = fopen(ncheck_path, "w");
        if (fp) {
                fprintf(fp, "0x%08llx\n", (long long)savet);
                if (fclose(fp) == 0)
                        rename(ncheck_path, ocheck_path);
                remove(ncheck_path);
        } else {
                fprintf(stderr, "hammer: Unable to create period-file %s: %s\n",
                        ncheck_path, strerror(errno));
        }
}

/*
 * Simply count the number of softlinks in the snapshots dir
 */
static int
check_softlinks(int fd, int new_config, const char *snapshots_path)
{
        struct dirent *den;
        struct stat st;
        DIR *dir;
        char *fpath;
        int res = 0;

        /*
         * Old-style softlink-based snapshots
         */
        if ((dir = opendir(snapshots_path)) != NULL) {
                while ((den = readdir(dir)) != NULL) {
                        if (den->d_name[0] == '.')
                                continue;
                        asprintf(&fpath, "%s/%s", snapshots_path, den->d_name);
                        if (lstat(fpath, &st) == 0 && S_ISLNK(st.st_mode))
                                ++res;
                        free(fpath);
                }
                closedir(dir);
        }

        /*
         * New-style snapshots are stored as filesystem meta-data,
         * count those too.
         */
        if (new_config) {
                struct hammer_ioc_snapshot snapshot;

                bzero(&snapshot, sizeof(snapshot));
                do {
                        if (ioctl(fd, HAMMERIOC_GET_SNAPSHOT, &snapshot) < 0) {
                                err(2, "hammer cleanup: check_softlink "
                                        "snapshot error");
                                /* not reached */
                        }
                        res += snapshot.count;
                } while (snapshot.head.error == 0 && snapshot.count);
        }
        return (res);
}

/*
 * Clean up expired softlinks in the snapshots dir
 */
static void
cleanup_softlinks(int fd, int new_config,
                  const char *snapshots_path, int arg2, char *arg3)
{
        struct dirent *den;
        struct stat st;
        DIR *dir;
        char *fpath;
        int anylink = 0;

        if (arg3 != NULL && strstr(arg3, "any") != NULL)
                anylink = 1;

        if ((dir = opendir(snapshots_path)) != NULL) {
                while ((den = readdir(dir)) != NULL) {
                        if (den->d_name[0] == '.')
                                continue;
                        asprintf(&fpath, "%s/%s", snapshots_path, den->d_name);
                        if (lstat(fpath, &st) == 0 && S_ISLNK(st.st_mode) &&
                            (anylink || strncmp(den->d_name, "snap-", 5) == 0)
                        ) {
                                if (check_expired(den->d_name, arg2)) {
                                        if (VerboseOpt) {
                                                printf("    expire %s\n",
                                                        fpath);
                                        }
                                        remove(fpath);
                                }
                        }
                        free(fpath);
                }
                closedir(dir);
        }

        /*
         * New-style snapshots are stored as filesystem meta-data,
         * count those too.
         */
        if (new_config) {
                struct hammer_ioc_snapshot snapshot;
                struct hammer_ioc_snapshot dsnapshot;
                struct hammer_snapshot_data *snap;
                struct tm *tp;
                time_t t;
                time_t dt;
                char snapts[32];
                u_int32_t i;

                bzero(&snapshot, sizeof(snapshot));
                bzero(&dsnapshot, sizeof(dsnapshot));
                do {
                        if (ioctl(fd, HAMMERIOC_GET_SNAPSHOT, &snapshot) < 0) {
                                err(2, "hammer cleanup: check_softlink "
                                        "snapshot error");
                                /* not reached */
                        }
                        for (i = 0; i < snapshot.count; ++i) {
                                snap = &snapshot.snaps[i];
                                t = snap->ts / 1000000ULL;
                                dt = time(NULL) - t;
                                if ((int)dt > arg2 || snap->tid == 0) {
                                        dsnapshot.snaps[dsnapshot.count++] =
                                                *snap;
                                }
                                if ((int)dt > arg2 && VerboseOpt) {
                                        tp = localtime(&t);
                                        strftime(snapts, sizeof(snapts),
                                                 "%Y-%m-%d %H:%M:%S %Z", tp);
                                        printf("    expire 0x%016jx %s %s\n",
                                               (uintmax_t)snap->tid,
                                               snapts,
                                               snap->label);
                                }
                                if (dsnapshot.count == HAMMER_SNAPS_PER_IOCTL)
                                        delete_snapshots(fd, &dsnapshot);
                        }
                } while (snapshot.head.error == 0 && snapshot.count);

                if (dsnapshot.count)
                        delete_snapshots(fd, &dsnapshot);
        }
}

static void
delete_snapshots(int fd, struct hammer_ioc_snapshot *dsnapshot)
{
        for (;;) {
                if (ioctl(fd, HAMMERIOC_DEL_SNAPSHOT, dsnapshot) < 0) {
                        printf("    Ioctl to delete snapshots failed: %s\n",
                               strerror(errno));
                        break;
                }
                if (dsnapshot->head.error) {
                        printf("    Ioctl to delete snapshots failed at "
                               "snap=%016jx: %s\n",
                               dsnapshot->snaps[dsnapshot->index].tid,
                               strerror(dsnapshot->head.error));
                        if (++dsnapshot->index < dsnapshot->count)
                                continue;
                }
                break;
        }
        dsnapshot->index = 0;
        dsnapshot->count = 0;
        dsnapshot->head.error = 0;
}

/*
 * Take a softlink path in the form snap-yyyymmdd-hhmm and the
 * expiration in seconds (arg2) and return non-zero if the softlink
 * has expired.
 */
static int
check_expired(const char *fpath, int arg2)
{
        struct tm tm;
        time_t t;
        int year;
        int month;
        int day = 0;
        int hour = 0;
        int minute = 0;
        int r;

        while (*fpath && *fpath != '-' && *fpath != '.')
                ++fpath;
        if (*fpath)
                ++fpath;

        r = sscanf(fpath, "%4d%2d%2d-%2d%2d",
                   &year, &month, &day, &hour, &minute);

        if (r >= 3) {
                bzero(&tm, sizeof(tm));
                tm.tm_isdst = -1;
                tm.tm_min = minute;
                tm.tm_hour = hour;
                tm.tm_mday = day;
                tm.tm_mon = month - 1;
                tm.tm_year = year - 1900;
                t = mktime(&tm);
                if (t == (time_t)-1)
                        return(0);
                t = time(NULL) - t;
                if ((int)t > arg2)
                        return(1);
        }
        return(0);
}

/*
 * Issue a snapshot.
 */
static int
create_snapshot(const char *path, const char *snapshots_path)
{
        int r;

        runcmd(&r, "hammer snapshot %s %s", path, snapshots_path);
        return(r);
}

static int
cleanup_prune(const char *path __unused, const char *snapshots_path,
                  int arg1 __unused, int arg2, int snapshots_disabled)
{
        /*
         * If snapshots have been disabled run prune-everything instead
         * of prune.
         */
        if (snapshots_disabled && arg2) {
                runcmd(NULL, "hammer -c %s/.prune.cycle -t %d prune-everything %s",
                        snapshots_path, arg2, path);
        } else if (snapshots_disabled) {
                runcmd(NULL, "hammer prune-everything %s", path);
        } else if (arg2) {
                runcmd(NULL, "hammer -c %s/.prune.cycle -t %d prune %s",
                        snapshots_path, arg2, snapshots_path);
        } else {
                runcmd(NULL, "hammer prune %s", snapshots_path);
        }
        return(0);
}

static int
cleanup_rebalance(const char *path, const char *snapshots_path,
                  int arg1 __unused, int arg2)
{
        if (VerboseOpt == 0) {
                printf(".");
                fflush(stdout);
        }

        runcmd(NULL,
               "hammer -c %s/.rebalance.cycle -t %d rebalance %s",
               snapshots_path, arg2, path);
        if (VerboseOpt == 0) {
                printf(".");
                fflush(stdout);
        }
        if (VerboseOpt == 0)
                printf("\n");
        return(0);
}

static int
cleanup_reblock(const char *path, const char *snapshots_path,
                  int arg1 __unused, int arg2)
{
        if (VerboseOpt == 0) {
                printf(".");
                fflush(stdout);
        }

        /*
         * When reblocking the B-Tree always reblock everything in normal
         * mode.
         */
        runcmd(NULL,
               "hammer -c %s/.reblock-1.cycle -t %d reblock-btree %s",
               snapshots_path, arg2, path);
        if (VerboseOpt == 0) {
                printf(".");
                fflush(stdout);
        }

        /*
         * When reblocking the inodes always reblock everything in normal
         * mode.
         */
        runcmd(NULL,
               "hammer -c %s/.reblock-2.cycle -t %d reblock-inodes %s",
               snapshots_path, arg2, path);
        if (VerboseOpt == 0) {
                printf(".");
                fflush(stdout);
        }

        /*
         * When reblocking the directories always reblock everything in normal
         * mode.
         */
        runcmd(NULL,
               "hammer -c %s/.reblock-4.cycle -t %d reblock-dirs %s",
               snapshots_path, arg2, path);
        if (VerboseOpt == 0) {
                printf(".");
                fflush(stdout);
        }

        /*
         * Do not reblock all the data in normal mode.
         */
        runcmd(NULL,
               "hammer -c %s/.reblock-3.cycle -t %d reblock-data %s 95",
               snapshots_path, arg2, path);
        if (VerboseOpt == 0)
                printf("\n");
        return(0);
}

static int
cleanup_recopy(const char *path, const char *snapshots_path,
                  int arg1 __unused, int arg2)
{
        if (VerboseOpt == 0) {
                printf(".");
                fflush(stdout);
        }
        runcmd(NULL,
               "hammer -c %s/.recopy-1.cycle -t %d reblock-btree %s",
               snapshots_path, arg2, path);
        if (VerboseOpt == 0) {
                printf(".");
                fflush(stdout);
        }
        runcmd(NULL,
               "hammer -c %s/.recopy-2.cycle -t %d reblock-inodes %s",
               snapshots_path, arg2, path);
        if (VerboseOpt == 0) {
                printf(".");
                fflush(stdout);
        }
        runcmd(NULL,
               "hammer -c %s/.recopy-4.cycle -t %d reblock-dirs %s",
               snapshots_path, arg2, path);
        if (VerboseOpt == 0) {
                printf(".");
                fflush(stdout);
        }
        runcmd(NULL,
               "hammer -c %s/.recopy-3.cycle -t %d reblock-data %s",
               snapshots_path, arg2, path);
        if (VerboseOpt == 0)
                printf("\n");
        return(0);
}

static
void
runcmd(int *resp, const char *ctl, ...)
{
        va_list va;
        char *cmd;
        char *arg;
        char **av;
        int n;
        int nmax;
        int res;
        pid_t pid;

        /*
         * Generate the command
         */
        va_start(va, ctl);
        vasprintf(&cmd, ctl, va);
        va_end(va);
        if (VerboseOpt)
                printf("    %s\n", cmd);

        /*
         * Break us down into arguments.  We do not just use system() here
         * because it blocks SIGINT and friends.
         */
        n = 0;
        nmax = 16;
        av = malloc(sizeof(char *) * nmax);

        for (arg = strtok(cmd, WS); arg; arg = strtok(NULL, WS)) {
                if (n == nmax - 1) {
                        nmax += 16;
                        av = realloc(av, sizeof(char *) * nmax);
                }
                av[n++] = arg;
        }
        av[n++] = NULL;

        /*
         * Run the command.
         */
        RunningIoctl = 1;
        if ((pid = fork()) == 0) {
                if (VerboseOpt < 2) {
                        int fd = open("/dev/null", O_RDWR);
                        dup2(fd, 1);
                        close(fd);
                }
                execvp(av[0], av);
                _exit(127);
        } else if (pid < 0) {
                res = 127;
        } else {
                int status;

                while (waitpid(pid, &status, 0) != pid)
                        ;
                res = WEXITSTATUS(status);
        }
        RunningIoctl = 0;
        if (DidInterrupt)
                _exit(1);

        free(cmd);
        free(av);
        if (resp)
                *resp = res;
}