[thirdparty/mdadm.git] / Assemble.c

/*
 * mdadm - manage Linux "md" devices aka RAID arrays.
 *
 * Copyright (C) 2001-2006 Neil Brown <neilb@suse.de>
 *
 *
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2 of the License, or
 *    (at your option) any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 *    Author: Neil Brown
 *    Email: <neilb@cse.unsw.edu.au>
 *    Paper: Neil Brown
 *           School of Computer Science and Engineering
 *           The University of New South Wales
 *           Sydney, 2052
 *           Australia
 */

#include        "mdadm.h"
#include        <ctype.h>

static int name_matches(char *found, char *required, char *homehost)
{
        /* See if the name found matches the required name, possibly
         * prefixed with 'homehost'
         */
        char fnd[33];

        strncpy(fnd, found, 32);
        fnd[32] = 0;
        if (strcmp(found, required)==0)
                return 1;
        if (homehost) {
                int l = strlen(homehost);
                if (l < 32 && fnd[l] == ':' &&
                    strcmp(fnd+l+1, required)==0)
                        return 1;
        }
        return 0;
}

/*static */ int is_member_busy(char *metadata_version)
{
        /* check if the given member array is active */
        struct mdstat_ent *mdstat = mdstat_read(1, 0);
        struct mdstat_ent *ent;
        int busy = 0;

        for (ent = mdstat; ent; ent = ent->next) {
                if (ent->metadata_version == NULL)
                        continue;
                if (strncmp(ent->metadata_version, "external:", 9) != 0)
                        continue;
                if (!is_subarray(&ent->metadata_version[9]))
                        continue;
                /* Skip first char - it can be '/' or '-' */
                if (strcmp(&ent->metadata_version[10], metadata_version+1) == 0) {
                        busy = 1;
                        break;
                }
        }
        free_mdstat(mdstat);

        return busy;
}

int Assemble(struct supertype *st, char *mddev,
             mddev_ident_t ident,
             mddev_dev_t devlist, char *backup_file,
             int readonly, int runstop,
             char *update, char *homehost,
             int verbose, int force)
{
        /*
         * The task of Assemble is to find a collection of
         * devices that should (according to their superblocks)
         * form an array, and to give this collection to the MD driver.
         * In Linux-2.4 and later, this involves submitting a
         * SET_ARRAY_INFO ioctl with no arg - to prepare
         * the array - and then submit a number of
         * ADD_NEW_DISK ioctls to add disks into
         * the array.  Finally RUN_ARRAY might
         * be submitted to start the array.
         *
         * Much of the work of Assemble is in finding and/or
         * checking the disks to make sure they look right.
         *
         * If mddev is not set, then scan must be set and we
         *  read through the config file for dev+uuid mapping
         *  We recurse, setting mddev, for each device that
         *    - isn't running
         *    - has a valid uuid (or any uuid if !uuidset)
         *
         * If mddev is set, we try to determine state of md.
         *   check version - must be at least 0.90.0
         *   check kernel version.  must be at least 2.4.
         *    If not, we can possibly fall back on START_ARRAY
         *   Try to GET_ARRAY_INFO.
         *     If possible, give up
         *     If not, try to STOP_ARRAY just to make sure
         *
         * If !uuidset and scan, look in conf-file for uuid
         *       If not found, give up
         * If !devlist and scan and uuidset, get list of devs from conf-file
         *
         * For each device:
         *   Check superblock - discard if bad
         *   Check uuid (set if we don't have one) - discard if no match
         *   Check superblock similarity if we have a superblock - discard if different
         *   Record events, devicenum
         * This should give us a list of devices for the array
         * We should collect the most recent event number
         *
         * Count disks with recent enough event count
         * While force && !enough disks
         *    Choose newest rejected disks, update event count
         *     mark clean and rewrite superblock
         * If recent kernel:
         *    SET_ARRAY_INFO
         *    foreach device with recent events : ADD_NEW_DISK
         *    if runstop == 1 || "enough" disks and runstop==0 -> RUN_ARRAY
         * If old kernel:
         *    Check the device numbers in superblock are right
         *    update superblock if any changes
         *    START_ARRAY
         *
         */
        int mdfd;
        int clean;
        int auto_assem = (mddev == NULL);
        int old_linux = 0;
        int vers = vers; /* Keep gcc quite - it really is initialised */
        struct {
                char *devname;
                int uptodate; /* set once we decide that this device is as
                               * recent as everything else in the array.
                               */
                struct mdinfo i;
        } *devices;
        int *best = NULL; /* indexed by raid_disk */
        unsigned int bestcnt = 0;
        int devcnt = 0;
        unsigned int okcnt, sparecnt;
        unsigned int req_cnt;
        unsigned int i;
        int most_recent = 0;
        int chosen_drive;
        int change = 0;
        int inargv = 0;
        int report_missmatch;
        int bitmap_done;
        int start_partial_ok = (runstop >= 0) && 
                (force || devlist==NULL || auto_assem);
        unsigned int num_devs;
        mddev_dev_t tmpdev;
        struct mdinfo info;
        struct mdinfo *content = NULL;
        mdu_array_info_t tmp_inf;
        char *avail;
        int nextspare = 0;
        char *name = NULL;
        int trustworthy;
        char chosen_name[1024];

        if (get_linux_version() < 2004000)
                old_linux = 1;

        /*
         * If any subdevs are listed, then any that don't
         * match ident are discarded.  Remainder must all match and
         * become the array.
         * If no subdevs, then we scan all devices in the config file, but
         * there must be something in the identity
         */

        if (!devlist &&
            ident->uuid_set == 0 &&
            ident->super_minor < 0 &&
            ident->devices == NULL) {
                fprintf(stderr, Name ": No identity information available for %s - cannot assemble.\n",
                        mddev ? mddev : "further assembly");
                return 1;
        }

        if (devlist == NULL)
                devlist = conf_get_devs();
        else if (mddev)
                inargv = 1;

        report_missmatch = ((inargv && verbose >= 0) || verbose > 0);
 try_again:
        /* We come back here when doing auto-assembly and attempting some
         * set of devices failed.  Those are now marked as ->used==2 and
         * we ignore them and try again
         */

        tmpdev = devlist; num_devs = 0;
        while (tmpdev) {
                if (tmpdev->used)
                        tmpdev->used = 2;
                else
                        num_devs++;
                tmpdev = tmpdev->next;
        }
        devices = malloc(num_devs * sizeof(*devices));

        if (!st && ident->st) st = ident->st;

        if (verbose>0)
            fprintf(stderr, Name ": looking for devices for %s\n",
                    mddev ? mddev : "further assembly");

        /* first walk the list of devices to find a consistent set
         * that match the criterea, if that is possible.
         * We flag the ones we like with 'used'.
         */
        for (tmpdev = devlist;
             tmpdev;
             tmpdev = tmpdev->next) {
                char *devname = tmpdev->devname;
                int dfd;
                struct stat stb;
                struct supertype *tst = dup_super(st);

                if (tmpdev->used > 1) continue;

                if (ident->devices &&
                    !match_oneof(ident->devices, devname)) {
                        if (report_missmatch)
                                fprintf(stderr, Name ": %s is not one of %s\n", devname, ident->devices);
                        continue;
                }

                dfd = dev_open(devname, O_RDONLY|O_EXCL);
                if (dfd < 0) {
                        if (report_missmatch)
                                fprintf(stderr, Name ": cannot open device %s: %s\n",
                                        devname, strerror(errno));
                        tmpdev->used = 2;
                } else if (fstat(dfd, &stb)< 0) {
                        /* Impossible! */
                        fprintf(stderr, Name ": fstat failed for %s: %s\n",
                                devname, strerror(errno));
                        tmpdev->used = 2;
                } else if ((stb.st_mode & S_IFMT) != S_IFBLK) {
                        fprintf(stderr, Name ": %s is not a block device.\n",
                                devname);
                        tmpdev->used = 2;
                } else if (!tst && (tst = guess_super(dfd)) == NULL) {
                        if (report_missmatch)
                                fprintf(stderr, Name ": no recogniseable superblock on %s\n",
                                        devname);
                        tmpdev->used = 2;
                } else if (tst->ss->load_super(tst,dfd, NULL)) {
                        if (report_missmatch)
                                fprintf( stderr, Name ": no RAID superblock on %s\n",
                                         devname);
                } else {
                        content = &info;
                        memset(content, 0, sizeof(*content));
                        tst->ss->getinfo_super(tst, content);
                }
                if (dfd >= 0) close(dfd);

                if (ident->uuid_set && (!update || strcmp(update, "uuid")!= 0) &&
                    (!tst || !tst->sb ||
                     same_uuid(content->uuid, ident->uuid, tst->ss->swapuuid)==0)) {
                        if (report_missmatch)
                                fprintf(stderr, Name ": %s has wrong uuid.\n",
                                        devname);
                        goto loop;
                }
                if (ident->name[0] && (!update || strcmp(update, "name")!= 0) &&
                    (!tst || !tst->sb ||
                     name_matches(content->name, ident->name, homehost)==0)) {
                        if (report_missmatch)
                                fprintf(stderr, Name ": %s has wrong name.\n",
                                        devname);
                        goto loop;
                }
                if (ident->super_minor != UnSet &&
                    (!tst || !tst->sb ||
                     ident->super_minor != content->array.md_minor)) {
                        if (report_missmatch)
                                fprintf(stderr, Name ": %s has wrong super-minor.\n",
                                        devname);
                        goto loop;
                }
                if (ident->level != UnSet &&
                    (!tst || !tst->sb ||
                     ident->level != content->array.level)) {
                        if (report_missmatch)
                                fprintf(stderr, Name ": %s has wrong raid level.\n",
                                        devname);
                        goto loop;
                }
                if (ident->raid_disks != UnSet &&
                    (!tst || !tst->sb ||
                     ident->raid_disks!= content->array.raid_disks)) {
                        if (report_missmatch)
                                fprintf(stderr, Name ": %s requires wrong number of drives.\n",
                                        devname);
                        goto loop;
                }
                if (auto_assem) {
                        if (tst == NULL || tst->sb == NULL)
                                continue;
                }
                /* If we are this far, then we are nearly commited to this device.
                 * If the super_block doesn't exist, or doesn't match others,
                 * then we probably cannot continue
                 * However if one of the arrays is for the homehost, and
                 * the other isn't that can disambiguate.
                 */

                if (!tst || !tst->sb) {
                        fprintf(stderr, Name ": %s has no superblock - assembly aborted\n",
                                devname);
                        if (st)
                                st->ss->free_super(st);
                        return 1;
                }

                if (st == NULL)
                        st = dup_super(tst);
                if (st->minor_version == -1)
                        st->minor_version = tst->minor_version;
                if (st->ss != tst->ss ||
                    st->minor_version != tst->minor_version ||
                    st->ss->compare_super(st, tst) != 0) {
                        /* Some mismatch. If exactly one array matches this host,
                         * we can resolve on that one.
                         * Or, if we are auto assembling, we just ignore the second
                         * for now.
                         */
                        if (auto_assem)
                                goto loop;
                        if (homehost) {
                                int first = st->ss->match_home(st, homehost);
                                int last = tst->ss->match_home(tst, homehost);
                                if (first != last &&
                                    (first == 1 || last == 1)) {
                                        /* We can do something */
                                        if (first) {/* just ignore this one */
                                                if (report_missmatch)
                                                        fprintf(stderr, Name ": %s misses out due to wrong homehost\n",
                                                                devname);
                                                goto loop;
                                        } else { /* reject all those sofar */
                                                mddev_dev_t td;
                                                if (report_missmatch)
                                                        fprintf(stderr, Name ": %s overrides previous devices due to good homehost\n",
                                                                devname);
                                                for (td=devlist; td != tmpdev; td=td->next)
                                                        if (td->used == 1)
                                                                td->used = 0;
                                                tmpdev->used = 1;
                                                goto loop;
                                        }
                                }
                        }
                        fprintf(stderr, Name ": superblock on %s doesn't match others - assembly aborted\n",
                                devname);
                        tst->ss->free_super(tst);
                        st->ss->free_super(st);
                        return 1;
                }

                tmpdev->used = 1;

        loop:
                if (tst)
                        tst->ss->free_super(tst);
        }

        if (!st || !st->sb || !content)
                return 2;

        /* Now need to open array the device.  Use create_mddev */
        if (content == &info)
                st->ss->getinfo_super(st, content);

        trustworthy = FOREIGN;
        switch (st->ss->match_home(st, homehost)) {
        case 0:
                trustworthy = FOREIGN;
                name = content->name;
                break;
        case 1:
                trustworthy = LOCAL;
                name = strchr(content->name, ':');
                if (name)
                        name++;
                else
                        name = content->name;
                break;
        case -1:
                trustworthy = FOREIGN;
                break;
        }
        if (!auto_assem && trustworthy == FOREIGN)
                /* If the array is listed in mdadm or on
                 * command line, then we trust the name
                 * even if the array doesn't look local
                 */
                trustworthy = LOCAL;

        if (content->name[0] == 0 &&
            content->array.level == LEVEL_CONTAINER) {
                name = content->text_version;
                trustworthy = METADATA;
        }
        mdfd = create_mddev(mddev, name, ident->autof, trustworthy,
                            chosen_name);
        if (mdfd < 0) {
                st->ss->free_super(st);
                free(devices);
                if (auto_assem)
                        goto try_again;
                return 1;
        }
        mddev = chosen_name;
        vers = md_get_version(mdfd);
        if (vers < 9000) {
                fprintf(stderr, Name ": Assemble requires driver version 0.90.0 or later.\n"
                        "    Upgrade your kernel or try --build\n");
                close(mdfd);
                return 1;
        }
        if (ioctl(mdfd, GET_ARRAY_INFO, &tmp_inf)==0) {
                fprintf(stderr, Name ": %s already active, cannot restart it!\n",
                        mddev);
                for (tmpdev = devlist ;
                     tmpdev && tmpdev->used != 1;
                     tmpdev = tmpdev->next)
                        ;
                if (tmpdev && auto_assem)
                        fprintf(stderr, Name ":   %s needed for %s...\n",
                                mddev, tmpdev->devname);
                close(mdfd);
                mdfd = -3;
                st->ss->free_super(st);
                free(devices);
                if (auto_assem)
                        goto try_again;
                return 1;
        }
        ioctl(mdfd, STOP_ARRAY, NULL); /* just incase it was started but has no content */

        /* Ok, no bad inconsistancy, we can try updating etc */
        bitmap_done = 0;
        for (tmpdev = devlist; tmpdev; tmpdev=tmpdev->next) if (tmpdev->used == 1) {
                char *devname = tmpdev->devname;
                struct stat stb;
                /* looks like a good enough match to update the super block if needed */
#ifndef MDASSEMBLE
                if (update) {
                        int dfd;
                        /* prepare useful information in info structures */
                        struct stat stb2;
                        struct supertype *tst;
                        fstat(mdfd, &stb2);

                        if (strcmp(update, "uuid")==0 &&
                            !ident->uuid_set) {
                                int rfd;
                                if ((rfd = open("/dev/urandom", O_RDONLY)) < 0 ||
                                    read(rfd, ident->uuid, 16) != 16) {
                                        *(__u32*)(ident->uuid) = random();
                                        *(__u32*)(ident->uuid+1) = random();
                                        *(__u32*)(ident->uuid+2) = random();
                                        *(__u32*)(ident->uuid+3) = random();
                                }
                                if (rfd >= 0) close(rfd);
                        }
                        dfd = dev_open(devname, O_RDWR|O_EXCL);

                        remove_partitions(dfd);

                        tst = dup_super(st);
                        tst->ss->load_super(tst, dfd, NULL);
                        tst->ss->getinfo_super(tst, content);

                        memcpy(content->uuid, ident->uuid, 16);
                        strcpy(content->name, ident->name);
                        content->array.md_minor = minor(stb2.st_rdev);

                        tst->ss->update_super(tst, content, update,
                                              devname, verbose,
                                              ident->uuid_set, homehost);
                        if (strcmp(update, "uuid")==0 &&
                            !ident->uuid_set) {
                                ident->uuid_set = 1;
                                memcpy(ident->uuid, content->uuid, 16);
                        }
                        if (dfd < 0)
                                fprintf(stderr, Name ": Cannot open %s for superblock update\n",
                                        devname);
                        else if (tst->ss->store_super(tst, dfd))
                                fprintf(stderr, Name ": Could not re-write superblock on %s.\n",
                                        devname);
                        if (dfd >= 0)
                                close(dfd);

                        if (strcmp(update, "uuid")==0 &&
                            ident->bitmap_fd >= 0 && !bitmap_done) {
                                if (bitmap_update_uuid(ident->bitmap_fd,
                                                       content->uuid,
                                                       tst->ss->swapuuid) != 0)
                                        fprintf(stderr, Name ": Could not update uuid on external bitmap.\n");
                                else
                                        bitmap_done = 1;
                        }
                        tst->ss->free_super(tst);
                } else
#endif
                {
                        struct supertype *tst = dup_super(st);
                        int dfd;
                        dfd = dev_open(devname, O_RDWR|O_EXCL);

                        remove_partitions(dfd);

                        tst->ss->load_super(tst, dfd, NULL);
                        tst->ss->getinfo_super(tst, content);
                        tst->ss->free_super(tst);
                        close(dfd);
                }

                stat(devname, &stb);

                if (verbose > 0)
                        fprintf(stderr, Name ": %s is identified as a member of %s, slot %d.\n",
                                devname, mddev, content->disk.raid_disk);
                devices[devcnt].devname = devname;
                devices[devcnt].uptodate = 0;
                devices[devcnt].i = *content;
                devices[devcnt].i.disk.major = major(stb.st_rdev);
                devices[devcnt].i.disk.minor = minor(stb.st_rdev);
                if (most_recent < devcnt) {
                        if (devices[devcnt].i.events
                            > devices[most_recent].i.events)
                                most_recent = devcnt;
                }
                if (content->array.level == -4)
                        /* with multipath, the raid_disk from the superblock is meaningless */
                        i = devcnt;
                else
                        i = devices[devcnt].i.disk.raid_disk;
                if (i+1 == 0) {
                        if (nextspare < content->array.raid_disks)
                                nextspare = content->array.raid_disks;
                        i = nextspare++;
                } else {
                        if (i >= content->array.raid_disks &&
                            i >= nextspare)
                                nextspare = i+1;
                }
                if (i < 10000) {
                        if (i >= bestcnt) {
                                unsigned int newbestcnt = i+10;
                                int *newbest = malloc(sizeof(int)*newbestcnt);
                                unsigned int c;
                                for (c=0; c < newbestcnt; c++)
                                        if (c < bestcnt)
                                                newbest[c] = best[c];
                                        else
                                                newbest[c] = -1;
                                if (best)free(best);
                                best = newbest;
                                bestcnt = newbestcnt;
                        }
                        if (best[i] >=0 &&
                            devices[best[i]].i.events
                            == devices[devcnt].i.events
                            && (devices[best[i]].i.disk.minor
                                != devices[devcnt].i.disk.minor)
                            && st->ss == &super0
                            && content->array.level != LEVEL_MULTIPATH) {
                                /* two different devices with identical superblock.
                                 * Could be a mis-detection caused by overlapping
                                 * partitions.  fail-safe.
                                 */
                                fprintf(stderr, Name ": WARNING %s and %s appear"
                                        " to have very similar superblocks.\n"
                                        "      If they are really different, "
                                        "please --zero the superblock on one\n"
                                        "      If they are the same or overlap,"
                                        " please remove one from %s.\n",
                                        devices[best[i]].devname, devname,
                                        inargv ? "the list" :
                                           "the\n      DEVICE list in mdadm.conf"
                                        );
                                close(mdfd);
                                return 1;
                        }
                        if (best[i] == -1
                            || (devices[best[i]].i.events
                                < devices[devcnt].i.events))
                                best[i] = devcnt;
                }
                devcnt++;
        }

        if (devcnt == 0) {
                fprintf(stderr, Name ": no devices found for %s\n",
                        mddev);
                if (st)
                        st->ss->free_super(st);
                close(mdfd);
                return 1;
        }

        if (update && strcmp(update, "byteorder")==0)
                st->minor_version = 90;

        st->ss->getinfo_super(st, content);
        clean = content->array.state & 1;

        /* now we have some devices that might be suitable.
         * I wonder how many
         */
        avail = malloc(content->array.raid_disks);
        memset(avail, 0, content->array.raid_disks);
        okcnt = 0;
        sparecnt=0;
        for (i=0; i< bestcnt ;i++) {
                int j = best[i];
                int event_margin = 1; /* always allow a difference of '1'
                                       * like the kernel does
                                       */
                if (j < 0) continue;
                /* note: we ignore error flags in multipath arrays
                 * as they don't make sense
                 */
                if (content->array.level != -4)
                        if (!(devices[j].i.disk.state & (1<<MD_DISK_SYNC))) {
                                if (!(devices[j].i.disk.state
                                      & (1<<MD_DISK_FAULTY)))
                                        sparecnt++;
                                continue;
                        }
                if (devices[j].i.events+event_margin >=
                    devices[most_recent].i.events) {
                        devices[j].uptodate = 1;
                        if (i < content->array.raid_disks) {
                                okcnt++;
                                avail[i]=1;
                        } else
                                sparecnt++;
                }
        }
        while (force && !enough(content->array.level, content->array.raid_disks,
                                content->array.layout, 1,
                                avail, okcnt)) {
                /* Choose the newest best drive which is
                 * not up-to-date, update the superblock
                 * and add it.
                 */
                int fd;
                struct supertype *tst;
                long long current_events;
                chosen_drive = -1;
                for (i=0; i<content->array.raid_disks && i < bestcnt; i++) {
                        int j = best[i];
                        if (j>=0 &&
                            !devices[j].uptodate &&
                            devices[j].i.events > 0 &&
                            (chosen_drive < 0 ||
                             devices[j].i.events
                             > devices[chosen_drive].i.events))
                                chosen_drive = j;
                }
                if (chosen_drive < 0)
                        break;
                current_events = devices[chosen_drive].i.events;
        add_another:
                if (verbose >= 0)
                        fprintf(stderr, Name ": forcing event count in %s(%d) from %d upto %d\n",
                                devices[chosen_drive].devname,
                                devices[chosen_drive].i.disk.raid_disk,
                                (int)(devices[chosen_drive].i.events),
                                (int)(devices[most_recent].i.events));
                fd = dev_open(devices[chosen_drive].devname, O_RDWR|O_EXCL);
                if (fd < 0) {
                        fprintf(stderr, Name ": Couldn't open %s for write - not updating\n",
                                devices[chosen_drive].devname);
                        devices[chosen_drive].i.events = 0;
                        continue;
                }
                tst = dup_super(st);
                if (tst->ss->load_super(tst,fd, NULL)) {
                        close(fd);
                        fprintf(stderr, Name ": RAID superblock disappeared from %s - not updating.\n",
                                devices[chosen_drive].devname);
                        devices[chosen_drive].i.events = 0;
                        continue;
                }
                content->events = devices[most_recent].i.events;
                tst->ss->update_super(tst, content, "force-one",
                                     devices[chosen_drive].devname, verbose,
                                     0, NULL);

                if (tst->ss->store_super(tst, fd)) {
                        close(fd);
                        fprintf(stderr, Name ": Could not re-write superblock on %s\n",
                                devices[chosen_drive].devname);
                        devices[chosen_drive].i.events = 0;
                        tst->ss->free_super(tst);
                        continue;
                }
                close(fd);
                devices[chosen_drive].i.events = devices[most_recent].i.events;
                devices[chosen_drive].uptodate = 1;
                avail[chosen_drive] = 1;
                okcnt++;
                tst->ss->free_super(tst);

                /* If there are any other drives of the same vintage,
                 * add them in as well.  We can't lose and we might gain
                 */
                for (i=0; i<content->array.raid_disks && i < bestcnt ; i++) {
                        int j = best[i];
                        if (j >= 0 &&
                            !devices[j].uptodate &&
                            devices[j].i.events > 0 &&
                            devices[j].i.events == current_events) {
                                chosen_drive = j;
                                goto add_another;
                        }
                }
        }

        /* Now we want to look at the superblock which the kernel will base things on
         * and compare the devices that we think are working with the devices that the
         * superblock thinks are working.
         * If there are differences and --force is given, then update this chosen
         * superblock.
         */
        chosen_drive = -1;
        st->ss->free_super(st);
        for (i=0; chosen_drive < 0 && i<bestcnt; i++) {
                int j = best[i];
                int fd;

                if (j<0)
                        continue;
                if (!devices[j].uptodate)
                        continue;
                chosen_drive = j;
                if ((fd=dev_open(devices[j].devname, O_RDONLY|O_EXCL))< 0) {
                        fprintf(stderr, Name ": Cannot open %s: %s\n",
                                devices[j].devname, strerror(errno));
                        close(mdfd);
                        return 1;
                }
                if (st->ss->load_super(st,fd, NULL)) {
                        close(fd);
                        fprintf(stderr, Name ": RAID superblock has disappeared from %s\n",
                                devices[j].devname);
                        close(mdfd);
                        return 1;
                }
                close(fd);
        }
        if (st->sb == NULL) {
                fprintf(stderr, Name ": No suitable drives found for %s\n", mddev);
                close(mdfd);
                return 1;
        }
        st->ss->getinfo_super(st, content);
#ifndef MDASSEMBLE
        sysfs_init(content, mdfd, 0);
#endif
        for (i=0; i<bestcnt; i++) {
                int j = best[i];
                unsigned int desired_state;

                if (i < content->array.raid_disks)
                        desired_state = (1<<MD_DISK_ACTIVE) | (1<<MD_DISK_SYNC);
                else
                        desired_state = 0;

                if (j<0)
                        continue;
                if (!devices[j].uptodate)
                        continue;

                devices[j].i.disk.state = desired_state;

                if (st->ss->update_super(st, &devices[j].i, "assemble", NULL,
                                         verbose, 0, NULL)) {
                        if (force) {
                                if (verbose >= 0)
                                        fprintf(stderr, Name ": "
                                                "clearing FAULTY flag for device %d in %s for %s\n",
                                                j, mddev, devices[j].devname);
                                change = 1;
                        } else {
                                if (verbose >= -1)
                                        fprintf(stderr, Name ": "
                                                "device %d in %s has wrong state in superblock, but %s seems ok\n",
                                                i, mddev, devices[j].devname);
                        }
                }
#if 0
                if (!(super.disks[i].i.disk.state & (1 << MD_DISK_FAULTY))) {
                        fprintf(stderr, Name ": devices %d of %s is not marked FAULTY in superblock, but cannot be found\n",
                                i, mddev);
                }
#endif
        }
        if (force && !clean &&
            !enough(content->array.level, content->array.raid_disks,
                    content->array.layout, clean,
                    avail, okcnt)) {
                change += st->ss->update_super(st, content, "force-array",
                                        devices[chosen_drive].devname, verbose,
                                               0, NULL);
                clean = 1;
        }

        if (change) {
                int fd;
                fd = dev_open(devices[chosen_drive].devname, O_RDWR|O_EXCL);
                if (fd < 0) {
                        fprintf(stderr, Name ": Could not open %s for write - cannot Assemble array.\n",
                                devices[chosen_drive].devname);
                        close(mdfd);
                        return 1;
                }
                if (st->ss->store_super(st, fd)) {
                        close(fd);
                        fprintf(stderr, Name ": Could not re-write superblock on %s\n",
                                devices[chosen_drive].devname);
                        close(mdfd);
                        return 1;
                }
                close(fd);
        }

        /* If we are in the middle of a reshape we may need to restore saved data
         * that was moved aside due to the reshape overwriting live data
         * The code of doing this lives in Grow.c
         */
#ifndef MDASSEMBLE
        if (content->reshape_active) {
                int err = 0;
                int *fdlist = malloc(sizeof(int)* bestcnt);
                for (i=0; i<bestcnt; i++) {
                        int j = best[i];
                        if (j >= 0) {
                                fdlist[i] = dev_open(devices[j].devname, O_RDWR|O_EXCL);
                                if (fdlist[i] < 0) {
                                        fprintf(stderr, Name ": Could not open %s for write - cannot Assemble array.\n",
                                                devices[j].devname);
                                        err = 1;
                                        break;
                                }
                        } else
                                fdlist[i] = -1;
                }
                if (!err)
                        err = Grow_restart(st, content, fdlist, bestcnt, backup_file);
                while (i>0) {
                        i--;
                        if (fdlist[i]>=0) close(fdlist[i]);
                }
                if (err) {
                        fprintf(stderr, Name ": Failed to restore critical section for reshape, sorry.\n");
                        close(mdfd);
                        return err;
                }
        }
#endif
        /* count number of in-sync devices according to the superblock.
         * We must have this number to start the array without -s or -R
         */
        req_cnt = content->array.working_disks;

        /* Almost ready to actually *do* something */
        if (!old_linux) {
                int rv;

                /* First, fill in the map, so that udev can find our name
                 * as soon as we become active.
                 */
                map_update(NULL, fd2devnum(mdfd), content->text_version,
                           content->uuid, chosen_name);

                rv = set_array_info(mdfd, st, content);
                if (rv) {
                        fprintf(stderr, Name ": failed to set array info for %s: %s\n",
                                mddev, strerror(errno));
                        close(mdfd);
                        return 1;
                }
                if (ident->bitmap_fd >= 0) {
                        if (ioctl(mdfd, SET_BITMAP_FILE, ident->bitmap_fd) != 0) {
                                fprintf(stderr, Name ": SET_BITMAP_FILE failed.\n");
                                close(mdfd);
                                return 1;
                        }
                } else if (ident->bitmap_file) {
                        /* From config file */
                        int bmfd = open(ident->bitmap_file, O_RDWR);
                        if (bmfd < 0) {
                                fprintf(stderr, Name ": Could not open bitmap file %s\n",
                                        ident->bitmap_file);
                                close(mdfd);
                                return 1;
                        }
                        if (ioctl(mdfd, SET_BITMAP_FILE, bmfd) != 0) {
                                fprintf(stderr, Name ": Failed to set bitmapfile for %s\n", mddev);
                                close(bmfd);
                                close(mdfd);
                                return 1;
                        }
                        close(bmfd);
                }

                /* First, add the raid disks, but add the chosen one last */
                for (i=0; i<= bestcnt; i++) {
                        int j;
                        if (i < bestcnt) {
                                j = best[i];
                                if (j == chosen_drive)
                                        continue;
                        } else
                                j = chosen_drive;

                        if (j >= 0 /* && devices[j].uptodate */) {
                                rv = add_disk(mdfd, st, content, &devices[j].i);

                                if (rv) {
                                        fprintf(stderr, Name ": failed to add "
                                                        "%s to %s: %s\n",
                                                devices[j].devname,
                                                mddev,
                                                strerror(errno));
                                        if (i < content->array.raid_disks
                                            || i == bestcnt)
                                                okcnt--;
                                        else
                                                sparecnt--;
                                } else if (verbose > 0)
                                        fprintf(stderr, Name ": added %s "
                                                        "to %s as %d\n",
                                                devices[j].devname, mddev,
                                                devices[j].i.disk.raid_disk);
                        } else if (verbose > 0 && i < content->array.raid_disks)
                                fprintf(stderr, Name ": no uptodate device for "
                                                "slot %d of %s\n",
                                        i, mddev);
                }

                if (content->array.level == LEVEL_CONTAINER) {
                        if (verbose >= 0) {
                                fprintf(stderr, Name ": Container %s has been "
                                        "assembled with %d drive%s",
                                        mddev, okcnt+sparecnt, okcnt+sparecnt==1?"":"s");
                                if (okcnt < content->array.raid_disks)
                                        fprintf(stderr, " (out of %d)",
                                                content->array.raid_disks);
                                fprintf(stderr, "\n");
                        }
                        sysfs_uevent(content, "change");
                        close(mdfd);
                        return 0;
                }

                if (runstop == 1 ||
                    (runstop <= 0 &&
                     ( enough(content->array.level, content->array.raid_disks,
                              content->array.layout, clean, avail, okcnt) &&
                       (okcnt >= req_cnt || start_partial_ok)
                             ))) {
                        if (ioctl(mdfd, RUN_ARRAY, NULL)==0) {
                                if (verbose >= 0) {
                                        fprintf(stderr, Name ": %s has been started with %d drive%s",
                                                mddev, okcnt, okcnt==1?"":"s");
                                        if (okcnt < content->array.raid_disks)
                                                fprintf(stderr, " (out of %d)", content->array.raid_disks);
                                        if (sparecnt)
                                                fprintf(stderr, " and %d spare%s", sparecnt, sparecnt==1?"":"s");
                                        fprintf(stderr, ".\n");
                                }
                                close(mdfd);
                                if (auto_assem) {
                                        int usecs = 1;
                                        /* There is a nasty race with 'mdadm --monitor'.
                                         * If it opens this device before we close it,
                                         * it gets an incomplete open on which IO
                                         * doesn't work and the capacity is
                                         * wrong.
                                         * If we reopen (to check for layered devices)
                                         * before --monitor closes, we loose.
                                         *
                                         * So: wait upto 1 second for there to be
                                         * a non-zero capacity.
                                         */
                                        while (usecs < 1000) {
                                                mdfd = open(mddev, O_RDONLY);
                                                if (mdfd >= 0) {
                                                        unsigned long long size;
                                                        if (get_dev_size(mdfd, NULL, &size) &&
                                                            size > 0)
                                                                break;
                                                        close(mdfd);
                                                }
                                                usleep(usecs);
                                                usecs <<= 1;
                                        }
                                }
                                return 0;
                        }
                        fprintf(stderr, Name ": failed to RUN_ARRAY %s: %s\n",
                                mddev, strerror(errno));

                        if (!enough(content->array.level, content->array.raid_disks,
                                    content->array.layout, 1, avail, okcnt))
                                fprintf(stderr, Name ": Not enough devices to "
                                        "start the array.\n");
                        else if (!enough(content->array.level,
                                         content->array.raid_disks,
                                         content->array.layout, clean,
                                         avail, okcnt))
                                fprintf(stderr, Name ": Not enough devices to "
                                        "start the array while not clean "
                                        "- consider --force.\n");

                        if (auto_assem)
                                ioctl(mdfd, STOP_ARRAY, NULL);
                        close(mdfd);
                        return 1;
                }
                if (runstop == -1) {
                        fprintf(stderr, Name ": %s assembled from %d drive%s",
                                mddev, okcnt, okcnt==1?"":"s");
                        if (okcnt != content->array.raid_disks)
                                fprintf(stderr, " (out of %d)", content->array.raid_disks);
                        fprintf(stderr, ", but not started.\n");
                        close(mdfd);
                        return 0;
                }
                if (verbose >= -1) {
                        fprintf(stderr, Name ": %s assembled from %d drive%s", mddev, okcnt, okcnt==1?"":"s");
                        if (sparecnt)
                                fprintf(stderr, " and %d spare%s", sparecnt, sparecnt==1?"":"s");
                        if (!enough(content->array.level, content->array.raid_disks,
                                    content->array.layout, 1, avail, okcnt))
                                fprintf(stderr, " - not enough to start the array.\n");
                        else if (!enough(content->array.level,
                                         content->array.raid_disks,
                                         content->array.layout, clean,
                                         avail, okcnt))
                                fprintf(stderr, " - not enough to start the "
                                        "array while not clean - consider "
                                        "--force.\n");
                        else {
                                if (req_cnt == content->array.raid_disks)
                                        fprintf(stderr, " - need all %d to start it", req_cnt);
                                else
                                        fprintf(stderr, " - need %d of %d to start", req_cnt, content->array.raid_disks);
                                fprintf(stderr, " (use --run to insist).\n");
                        }
                }
                if (auto_assem)
                        ioctl(mdfd, STOP_ARRAY, NULL);
                return 1;
        } else {
                /* The "chosen_drive" is a good choice, and if necessary, the superblock has
                 * been updated to point to the current locations of devices.
                 * so we can just start the array
                 */
                unsigned long dev;
                dev = makedev(devices[chosen_drive].i.disk.major,
                            devices[chosen_drive].i.disk.minor);
                if (ioctl(mdfd, START_ARRAY, dev)) {
                    fprintf(stderr, Name ": Cannot start array: %s\n",
                            strerror(errno));
                }

        }
        close(mdfd);
        return 0;
}

#ifndef MDASSEMBLE
int assemble_container_content(struct supertype *st, int mdfd,
                               struct mdinfo *content, int runstop,
                               char *chosen_name, int verbose)
{
        struct mdinfo *dev, *sra;
        int working = 0, preexist = 0;
        struct map_ent *map = NULL;

        sysfs_init(content, mdfd, 0);

        sra = sysfs_read(mdfd, 0, GET_VERSION);
        if (sra == NULL || strcmp(sra->text_version, content->text_version) != 0)
                if (sysfs_set_array(content, md_get_version(mdfd)) != 0)
                        return 1;
        if (sra)
                sysfs_free(sra);

        for (dev = content->devs; dev; dev = dev->next)
                if (sysfs_add_disk(content, dev) == 0)
                        working++;
                else if (errno == EEXIST)
                        preexist++;
        if (working == 0)
                /* Nothing new, don't try to start */ ;
        else if (runstop > 0 ||
                 (working + preexist) >= content->array.working_disks) {
                switch(content->array.level) {
                case LEVEL_LINEAR:
                case LEVEL_MULTIPATH:
                case 0:
                        sysfs_set_str(content, NULL, "array_state",
                                      "active");
                        break;
                default:
                        sysfs_set_str(content, NULL, "array_state",
                                      "readonly");
                        /* start mdmon if needed. */
                        if (!mdmon_running(st->container_dev))
                                start_mdmon(st->container_dev);
                        ping_monitor(devnum2devname(st->container_dev));
                        break;
                }
                sysfs_set_safemode(content, content->safe_mode_delay);
                if (verbose >= 0) {
                        fprintf(stderr, Name
                                ": Started %s with %d devices",
                                chosen_name, working + preexist);
                        if (preexist)
                                fprintf(stderr, " (%d new)", working);
                        fprintf(stderr, "\n");
                }
                /* FIXME should have an O_EXCL and wait for read-auto */
        } else
                if (verbose >= 0)
                        fprintf(stderr, Name
                                ": %s assembled with %d devices but "
                                "not started\n",
                                chosen_name, working);
        map_update(&map, fd2devnum(mdfd),
                   content->text_version,
                   content->uuid, chosen_name);

        return 0;
}
#endif