conf/assemble: new config line "auto".

[thirdparty/mdadm.git] / Incremental.c

/*
 * Incremental.c - support --incremental.  Part of:
 * mdadm - manage Linux "md" devices aka RAID arrays.
 *
 * Copyright (C) 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@suse.de>
 *    Paper: Neil Brown
 *           Novell Inc
 *           GPO Box Q1283
 *           QVB Post Office, NSW 1230
 *           Australia
 */

#include        "mdadm.h"

static int count_active(struct supertype *st, int mdfd, char **availp,
                        struct mdinfo *info);
static void find_reject(int mdfd, struct supertype *st, struct mdinfo *sra,
                        int number, __u64 events, int verbose,
                        char *array_name);

int Incremental(char *devname, int verbose, int runstop,
                struct supertype *st, char *homehost, int autof)
{
        /* Add this device to an array, creating the array if necessary
         * and starting the array if sensible or - if runstop>0 - if possible.
         *
         * This has several steps:
         *
         * 1/ Check if device is permitted by mdadm.conf, reject if not.
         * 2/ Find metadata, reject if none appropriate (check
         *       version/name from args)
         * 3/ Check if there is a match in mdadm.conf
         * 3a/ if not, check for homehost match.  If no match, assemble as
         *    a 'foreign' array.
         * 4/ Determine device number.
         * - If in mdadm.conf with std name, use that
         * - UUID in /var/run/mdadm.map  use that
         * - If name is suggestive, use that. unless in use with different uuid.
         * - Choose a free, high number.
         * - Use a partitioned device unless strong suggestion not to.
         *         e.g. auto=md
         *   Don't choose partitioned for containers.
         * 5/ Find out if array already exists
         * 5a/ if it does not
         * - choose a name, from mdadm.conf or 'name' field in array.
         * - create the array
         * - add the device
         * 5b/ if it does
         * - check one drive in array to make sure metadata is a reasonably
         *       close match.  Reject if not (e.g. different type)
         * - add the device
         * 6/ Make sure /var/run/mdadm.map contains this array.
         * 7/ Is there enough devices to possibly start the array?
         *     For a container, this means running Incremental_container.
         * 7a/ if not, finish with success.
         * 7b/ if yes,
         * - read all metadata and arrange devices like -A does
         * - if number of OK devices match expected, or -R and there are enough,
         *   start the array (auto-readonly).
         */
        struct stat stb;
        struct mdinfo info;
        struct mddev_ident_s *array_list, *match;
        char chosen_name[1024];
        int rv;
        struct map_ent *mp, *map = NULL;
        int dfd, mdfd;
        char *avail;
        int active_disks;
        int trustworthy = FOREIGN;
        char *name_to_use;
        mdu_array_info_t ainf;

        struct createinfo *ci = conf_get_create_info();


        /* 1/ Check if device is permitted by mdadm.conf */

        if (!conf_test_dev(devname)) {
                if (verbose >= 0)
                        fprintf(stderr, Name
                                ": %s not permitted by mdadm.conf.\n",
                                devname);
                return 1;
        }

        /* 2/ Find metadata, reject if none appropriate (check
         *            version/name from args) */

        dfd = dev_open(devname, O_RDONLY|O_EXCL);
        if (dfd < 0) {
                if (verbose >= 0)
                        fprintf(stderr, Name ": cannot open %s: %s.\n",
                                devname, strerror(errno));
                return 1;
        }
        if (fstat(dfd, &stb) < 0) {
                if (verbose >= 0)
                        fprintf(stderr, Name ": fstat failed for %s: %s.\n",
                                devname, strerror(errno));
                close(dfd);
                return 1;
        }
        if ((stb.st_mode & S_IFMT) != S_IFBLK) {
                if (verbose >= 0)
                        fprintf(stderr, Name ": %s is not a block device.\n",
                                devname);
                close(dfd);
                return 1;
        }

        if (st == NULL && (st = guess_super(dfd)) == NULL) {
                if (verbose >= 0)
                        fprintf(stderr, Name
                                ": no recognisable superblock on %s.\n",
                                devname);
                close(dfd);
                return 1;
        }
        if (st->ss->load_super(st, dfd, NULL)) {
                if (verbose >= 0)
                        fprintf(stderr, Name ": no RAID superblock on %s.\n",
                                devname);
                close(dfd);
                return 1;
        }
        close (dfd);

        memset(&info, 0, sizeof(info));
        st->ss->getinfo_super(st, &info);
        /* 3/ Check if there is a match in mdadm.conf */

        array_list = conf_get_ident(NULL);
        match = NULL;
        for (; array_list; array_list = array_list->next) {
                if (array_list->uuid_set &&
                    same_uuid(array_list->uuid, info.uuid, st->ss->swapuuid)
                    == 0) {
                        if (verbose >= 2 && array_list->devname)
                                fprintf(stderr, Name
                                        ": UUID differs from %s.\n",
                                        array_list->devname);
                        continue;
                }
                if (array_list->name[0] &&
                    strcasecmp(array_list->name, info.name) != 0) {
                        if (verbose >= 2 && array_list->devname)
                                fprintf(stderr, Name
                                        ": Name differs from %s.\n",
                                        array_list->devname);
                        continue;
                }
                if (array_list->devices &&
                    !match_oneof(array_list->devices, devname)) {
                        if (verbose >= 2 && array_list->devname)
                                fprintf(stderr, Name
                                        ": Not a listed device for %s.\n",
                                        array_list->devname);
                        continue;
                }
                if (array_list->super_minor != UnSet &&
                    array_list->super_minor != info.array.md_minor) {
                        if (verbose >= 2 && array_list->devname)
                                fprintf(stderr, Name
                                        ": Different super-minor to %s.\n",
                                        array_list->devname);
                        continue;
                }
                if (!array_list->uuid_set &&
                    !array_list->name[0] &&
                    !array_list->devices &&
                    array_list->super_minor == UnSet) {
                        if (verbose >= 2 && array_list->devname)
                                fprintf(stderr, Name
                             ": %s doesn't have any identifying information.\n",
                                        array_list->devname);
                        continue;
                }
                /* FIXME, should I check raid_disks and level too?? */

                if (match) {
                        if (verbose >= 0) {
                                if (match->devname && array_list->devname)
                                        fprintf(stderr, Name
                   ": we match both %s and %s - cannot decide which to use.\n",
                                                match->devname, array_list->devname);
                                else
                                        fprintf(stderr, Name
                                                ": multiple lines in mdadm.conf match\n");
                        }
                        return 2;
                }
                match = array_list;
        }

        if (match && match->devname
            && strcasecmp(match->devname, "<ignore>") == 0) {
                if (verbose >= 0)
                        fprintf(stderr, Name ": array containing %s is explicitly"
                                " ignored by mdadm.conf\n",
                                devname);
                return 1;
        }

        if (!match && !conf_test_metadata(st->ss->name)) {
                if (verbose >= 1)
                        fprintf(stderr, Name
                                ": %s has metadata type %s for which "
                                "auto-assembly is disabled\n",
                                devname, st->ss->name);
                return 1;
        }

        /* 3a/ if not, check for homehost match.  If no match, continue
         * but don't trust the 'name' in the array. Thus a 'random' minor
         * number will be assigned, and the device name will be based
         * on that. */
        if (match)
                trustworthy = LOCAL;
        else if ((homehost == NULL ||
                  st->ss->match_home(st, homehost) != 1) &&
                 st->ss->match_home(st, "any") != 1)
                trustworthy = FOREIGN;
        else
                trustworthy = LOCAL;

        /* There are three possible sources for 'autof':  command line,
         * ARRAY line in mdadm.conf, or CREATE line in mdadm.conf.
         * ARRAY takes precedence, then command line, then
         * CREATE.
         */
        if (match && match->autof)
                autof = match->autof;
        if (autof == 0)
                autof = ci->autof;

        if (st->ss->container_content && st->loaded_container) {
                /* This is a pre-built container array, so we do something
                 * rather different.
                 */
                return Incremental_container(st, devname, verbose, runstop,
                                             autof, trustworthy);
        }
        name_to_use = strchr(info.name, ':');
        if (name_to_use)
                name_to_use++;
        else
                name_to_use = info.name;

        if ((!name_to_use || name_to_use[0] == 0) &&
            info.array.level == LEVEL_CONTAINER &&
            trustworthy == LOCAL) {
                name_to_use = info.text_version;
                trustworthy = METADATA;
        }

        /* 4/ Check if array exists.
         */
        map_lock(&map);
        mp = map_by_uuid(&map, info.uuid);
        if (mp) {
                mdfd = open_mddev(mp->path, 0);
                if (mdfd < 0 && mddev_busy(mp->devnum)) {
                        /* maybe udev hasn't created it yet. */
                        char buf[50];
                        sprintf(buf, "%d:%d", dev2major(mp->devnum),
                                dev2minor(mp->devnum));
                        mdfd = dev_open(buf, O_RDWR);
                }
        } else
                mdfd = -1;

        if (mdfd < 0) {
                struct mdinfo *sra;
                struct mdinfo dinfo;

                /* Couldn't find an existing array, maybe make a new one */
                mdfd = create_mddev(match ? match->devname : NULL,
                                    name_to_use, autof, trustworthy, chosen_name);

                if (mdfd < 0)
                        return 1;

                sysfs_init(&info, mdfd, 0);

                if (set_array_info(mdfd, st, &info) != 0) {
                        fprintf(stderr, Name ": failed to set array info for %s: %s\n",
                                chosen_name, strerror(errno));
                        close(mdfd);
                        return 2;
                }

                dinfo = info;
                dinfo.disk.major = major(stb.st_rdev);
                dinfo.disk.minor = minor(stb.st_rdev);
                if (add_disk(mdfd, st, &info, &dinfo) != 0) {
                        fprintf(stderr, Name ": failed to add %s to %s: %s.\n",
                                devname, chosen_name, strerror(errno));
                        ioctl(mdfd, STOP_ARRAY, 0);
                        close(mdfd);
                        return 2;
                }
                sra = sysfs_read(mdfd, fd2devnum(mdfd), GET_DEVS);
                if (!sra || !sra->devs || sra->devs->disk.raid_disk >= 0) {
                        /* It really should be 'none' - must be old buggy
                         * kernel, and mdadm -I may not be able to complete.
                         * So reject it.
                         */
                        ioctl(mdfd, STOP_ARRAY, NULL);
                        fprintf(stderr, Name
                      ": You have an old buggy kernel which cannot support\n"
                                "      --incremental reliably.  Aborting.\n");
                        close(mdfd);
                        sysfs_free(sra);
                        return 2;
                }
                info.array.working_disks = 1;
                sysfs_free(sra);
                /* 6/ Make sure /var/run/mdadm.map contains this array. */
                map_update(&map, fd2devnum(mdfd),
                           info.text_version,
                           info.uuid, chosen_name);
        } else {
        /* 5b/ if it does */
        /* - check one drive in array to make sure metadata is a reasonably */
        /*        close match.  Reject if not (e.g. different type) */
        /* - add the device */
                char dn[20];
                int dfd2;
                int err;
                struct mdinfo *sra;
                struct supertype *st2;
                struct mdinfo info2, *d;

                strcpy(chosen_name, mp->path);

                sra = sysfs_read(mdfd, fd2devnum(mdfd), (GET_DEVS | GET_STATE));

                if (sra->devs) {
                        sprintf(dn, "%d:%d", sra->devs->disk.major,
                                sra->devs->disk.minor);
                        dfd2 = dev_open(dn, O_RDONLY);
                        st2 = dup_super(st);
                        if (st2->ss->load_super(st2, dfd2, NULL) ||
                            st->ss->compare_super(st, st2) != 0) {
                                fprintf(stderr, Name
                                        ": metadata mismatch between %s and "
                                        "chosen array %s\n",
                                        devname, chosen_name);
                                close(mdfd);
                                close(dfd2);
                                return 2;
                        }
                        close(dfd2);
                        memset(&info2, 0, sizeof(info2));
                        st2->ss->getinfo_super(st2, &info2);
                        st2->ss->free_super(st2);
                        if (info.array.level != info2.array.level ||
                            memcmp(info.uuid, info2.uuid, 16) != 0 ||
                            info.array.raid_disks != info2.array.raid_disks) {
                                fprintf(stderr, Name
                                        ": unexpected difference between %s and %s.\n",
                                        chosen_name, devname);
                                close(mdfd);
                                return 2;
                        }
                }
                info2.disk.major = major(stb.st_rdev);
                info2.disk.minor = minor(stb.st_rdev);
                /* add disk needs to know about containers */
                if (st->ss->external)
                        sra->array.level = LEVEL_CONTAINER;
                err = add_disk(mdfd, st2, sra, &info2);
                if (err < 0 && errno == EBUSY) {
                        /* could be another device present with the same
                         * disk.number. Find and reject any such
                         */
                        find_reject(mdfd, st, sra, info.disk.number,
                                    info.events, verbose, chosen_name);
                        err = add_disk(mdfd, st2, sra, &info2);
                }
                if (err < 0) {
                        fprintf(stderr, Name ": failed to add %s to %s: %s.\n",
                                devname, chosen_name, strerror(errno));
                        close(mdfd);
                        return 2;
                }
                info.array.working_disks = 0;
                for (d = sra->devs; d; d=d->next)
                        info.array.working_disks ++;
                        
        }

        /* 7/ Is there enough devices to possibly start the array? */
        /* 7a/ if not, finish with success. */
        if (info.array.level == LEVEL_CONTAINER) {
                /* Try to assemble within the container */
                map_unlock(&map);
                sysfs_uevent(&info, "change");
                if (verbose >= 0)
                        fprintf(stderr, Name
                                ": container %s now has %d devices\n",
                                chosen_name, info.array.working_disks);
                wait_for(chosen_name, mdfd);
                close(mdfd);
                if (runstop < 0)
                        return 0; /* don't try to assemble */
                rv = Incremental(chosen_name, verbose, runstop,
                                 NULL, homehost, autof);
                if (rv == 1)
                        /* Don't fail the whole -I if a subarray didn't
                         * have enough devices to start yet
                         */
                        rv = 0;
                return rv;
        }
        avail = NULL;
        active_disks = count_active(st, mdfd, &avail, &info);
        if (enough(info.array.level, info.array.raid_disks,
                   info.array.layout, info.array.state & 1,
                   avail, active_disks) == 0 ||
            (runstop < 0 && active_disks < info.array.raid_disks)) {
                free(avail);
                if (verbose >= 0)
                        fprintf(stderr, Name
                             ": %s attached to %s, not enough to start (%d).\n",
                                devname, chosen_name, active_disks);
                map_unlock(&map);
                close(mdfd);
                return 0;
        }
        free(avail);

        /* 7b/ if yes, */
        /* - if number of OK devices match expected, or -R and there */
        /*             are enough, */
        /*   + add any bitmap file  */
        /*   + start the array (auto-readonly). */

        if (ioctl(mdfd, GET_ARRAY_INFO, &ainf) == 0) {
                if (verbose >= 0)
                        fprintf(stderr, Name
                           ": %s attached to %s which is already active.\n",
                                devname, chosen_name);
                close(mdfd);
                map_unlock(&map);
                return 0;
        }

        map_unlock(&map);
        if (runstop > 0 || active_disks >= info.array.working_disks) {
                struct mdinfo *sra;
                /* Let's try to start it */
                if (match && match->bitmap_file) {
                        int bmfd = open(match->bitmap_file, O_RDWR);
                        if (bmfd < 0) {
                                fprintf(stderr, Name
                                        ": Could not open bitmap file %s.\n",
                                        match->bitmap_file);
                                close(mdfd);
                                return 1;
                        }
                        if (ioctl(mdfd, SET_BITMAP_FILE, bmfd) != 0) {
                                close(bmfd);
                                fprintf(stderr, Name
                                        ": Failed to set bitmapfile for %s.\n",
                                        chosen_name);
                                close(mdfd);
                                return 1;
                        }
                        close(bmfd);
                }
                sra = sysfs_read(mdfd, fd2devnum(mdfd), 0);
                if ((sra == NULL || active_disks >= info.array.working_disks)
                    && trustworthy != FOREIGN)
                        rv = ioctl(mdfd, RUN_ARRAY, NULL);
                else
                        rv = sysfs_set_str(sra, NULL,
                                           "array_state", "read-auto");
                if (rv == 0) {
                        if (verbose >= 0)
                                fprintf(stderr, Name
                           ": %s attached to %s, which has been started.\n",
                                        devname, chosen_name);
                        rv = 0;
                        wait_for(chosen_name, mdfd);
                } else {
                        fprintf(stderr, Name
                             ": %s attached to %s, but failed to start: %s.\n",
                                devname, chosen_name, strerror(errno));
                        rv = 1;
                }
        } else {
                if (verbose >= 0)
                        fprintf(stderr, Name
                          ": %s attached to %s, not enough to start safely.\n",
                                devname, chosen_name);
                rv = 0;
        }
        close(mdfd);
        return rv;
}

static void find_reject(int mdfd, struct supertype *st, struct mdinfo *sra,
                        int number, __u64 events, int verbose,
                        char *array_name)
{
        /* Find a device attached to this array with a disk.number of number
         * and events less than the passed events, and remove the device.
         */
        struct mdinfo *d;
        mdu_array_info_t ra;

        if (ioctl(mdfd, GET_ARRAY_INFO, &ra) == 0)
                return; /* not safe to remove from active arrays
                         * without thinking more */

        for (d = sra->devs; d ; d = d->next) {
                char dn[10];
                int dfd;
                struct mdinfo info;
                sprintf(dn, "%d:%d", d->disk.major, d->disk.minor);
                dfd = dev_open(dn, O_RDONLY);
                if (dfd < 0)
                        continue;
                if (st->ss->load_super(st, dfd, NULL)) {
                        close(dfd);
                        continue;
                }
                st->ss->getinfo_super(st, &info);
                st->ss->free_super(st);
                close(dfd);

                if (info.disk.number != number ||
                    info.events >= events)
                        continue;

                if (d->disk.raid_disk > -1)
                        sysfs_set_str(sra, d, "slot", "none");
                if (sysfs_set_str(sra, d, "state", "remove") == 0)
                        if (verbose >= 0)
                                fprintf(stderr, Name
                                        ": removing old device %s from %s\n",
                                        d->sys_name+4, array_name);
        }
}

static int count_active(struct supertype *st, int mdfd, char **availp,
                        struct mdinfo *bestinfo)
{
        /* count how many devices in sra think they are active */
        struct mdinfo *d;
        int cnt = 0, cnt1 = 0;
        __u64 max_events = 0;
        struct mdinfo *sra = sysfs_read(mdfd, -1, GET_DEVS | GET_STATE);
        char *avail = NULL;

        for (d = sra->devs ; d ; d = d->next) {
                char dn[30];
                int dfd;
                int ok;
                struct mdinfo info;

                sprintf(dn, "%d:%d", d->disk.major, d->disk.minor);
                dfd = dev_open(dn, O_RDONLY);
                if (dfd < 0)
                        continue;
                ok =  st->ss->load_super(st, dfd, NULL);
                close(dfd);
                if (ok != 0)
                        continue;
                st->ss->getinfo_super(st, &info);
                if (!avail) {
                        avail = malloc(info.array.raid_disks);
                        if (!avail) {
                                fprintf(stderr, Name ": out of memory.\n");
                                exit(1);
                        }
                        memset(avail, 0, info.array.raid_disks);
                        *availp = avail;
                }

                if (info.disk.state & (1<<MD_DISK_SYNC))
                {
                        if (cnt == 0) {
                                cnt++;
                                max_events = info.events;
                                avail[info.disk.raid_disk] = 2;
                                st->ss->getinfo_super(st, bestinfo);
                        } else if (info.events == max_events) {
                                cnt++;
                                avail[info.disk.raid_disk] = 2;
                        } else if (info.events == max_events-1) {
                                cnt1++;
                                avail[info.disk.raid_disk] = 1;
                        } else if (info.events < max_events - 1)
                                ;
                        else if (info.events == max_events+1) {
                                int i;
                                cnt1 = cnt;
                                cnt = 1;
                                max_events = info.events;
                                for (i=0; i<info.array.raid_disks; i++)
                                        if (avail[i])
                                                avail[i]--;
                                avail[info.disk.raid_disk] = 2;
                                st->ss->getinfo_super(st, bestinfo);
                        } else { /* info.events much bigger */
                                cnt = 1; cnt1 = 0;
                                memset(avail, 0, info.disk.raid_disk);
                                max_events = info.events;
                                st->ss->getinfo_super(st, bestinfo);
                        }
                }
                st->ss->free_super(st);
        }
        return cnt + cnt1;
}

int IncrementalScan(int verbose)
{
        /* look at every device listed in the 'map' file.
         * If one is found that is not running then:
         *  look in mdadm.conf for bitmap file.
         *   if one exists, but array has none, add it.
         *  try to start array in auto-readonly mode
         */
        struct map_ent *mapl = NULL;
        struct map_ent *me;
        mddev_ident_t devs, mddev;
        int rv = 0;

        map_read(&mapl);
        devs = conf_get_ident(NULL);

        for (me = mapl ; me ; me = me->next) {
                mdu_array_info_t array;
                mdu_bitmap_file_t bmf;
                struct mdinfo *sra;
                int mdfd = open_mddev(me->path, 0);

                if (mdfd < 0)
                        continue;
                if (ioctl(mdfd, GET_ARRAY_INFO, &array) == 0 ||
                    errno != ENODEV) {
                        close(mdfd);
                        continue;
                }
                /* Ok, we can try this one.   Maybe it needs a bitmap */
                for (mddev = devs ; mddev ; mddev = mddev->next)
                        if (mddev->devname
                            && strcmp(mddev->devname, me->path) == 0)
                                break;
                if (mddev && mddev->bitmap_file) {
                        /*
                         * Note: early kernels will wrongly fail this, so it
                         * is a hint only
                         */
                        int added = -1;
                        if (ioctl(mdfd, GET_ARRAY_INFO, &bmf) < 0) {
                                int bmfd = open(mddev->bitmap_file, O_RDWR);
                                if (bmfd >= 0) {
                                        added = ioctl(mdfd, SET_BITMAP_FILE,
                                                      bmfd);
                                        close(bmfd);
                                }
                        }
                        if (verbose >= 0) {
                                if (added == 0)
                                        fprintf(stderr, Name
                                                ": Added bitmap %s to %s\n",
                                                mddev->bitmap_file, me->path);
                                else if (errno != EEXIST)
                                        fprintf(stderr, Name
                                           ": Failed to add bitmap to %s: %s\n",
                                                me->path, strerror(errno));
                        }
                }
                sra = sysfs_read(mdfd, 0, 0);
                if (sra) {
                        if (sysfs_set_str(sra, NULL,
                                          "array_state", "read-auto") == 0) {
                                if (verbose >= 0)
                                        fprintf(stderr, Name
                                                ": started array %s\n",
                                                me->path);
                        } else {
                                fprintf(stderr, Name
                                        ": failed to start array %s: %s\n",
                                        me->path, strerror(errno));
                                rv = 1;
                        }
                }
        }
        return rv;
}

static char *container2devname(char *devname)
{
        char *mdname = NULL;

        if (devname[0] == '/') {
                int fd = open(devname, O_RDONLY);
                if (fd >= 0) {
                        mdname = devnum2devname(fd2devnum(fd));
                        close(fd);
                }
        } else {
                int uuid[4];
                struct map_ent *mp, *map = NULL;
                                        
                if (!parse_uuid(devname, uuid))
                        return mdname;
                mp = map_by_uuid(&map, uuid);
                if (mp)
                        mdname = devnum2devname(mp->devnum);
                map_free(map);
        }

        return mdname;
}

int Incremental_container(struct supertype *st, char *devname, int verbose,
                          int runstop, int autof, int trustworthy)
{
        /* Collect the contents of this container and for each
         * array, choose a device name and assemble the array.
         */

        struct mdinfo *list = st->ss->container_content(st);
        struct mdinfo *ra;
        struct map_ent *map = NULL;

        map_lock(&map);

        for (ra = list ; ra ; ra = ra->next) {
                int mdfd;
                char chosen_name[1024];
                struct map_ent *mp;
                struct mddev_ident_s *match = NULL;

                mp = map_by_uuid(&map, ra->uuid);

                if (mp) {
                        mdfd = open_dev(mp->devnum);
                        strcpy(chosen_name, mp->path);
                } else {

                        /* Check in mdadm.conf for container == devname and
                         * member == ra->text_version after second slash.
                         */
                        char *sub = strchr(ra->text_version+1, '/');
                        struct mddev_ident_s *array_list;
                        if (sub) {
                                sub++;
                                array_list = conf_get_ident(NULL);
                        } else
                                array_list = NULL;
                        for(; array_list ; array_list = array_list->next) {
                                char *dn;
                                if (array_list->member == NULL ||
                                    array_list->container == NULL)
                                        continue;
                                if (strcmp(array_list->member, sub) != 0)
                                        continue;
                                if (array_list->uuid_set &&
                                    !same_uuid(ra->uuid, array_list->uuid, st->ss->swapuuid))
                                        continue;
                                dn = container2devname(array_list->container);
                                if (dn == NULL)
                                        continue;
                                if (strncmp(dn, ra->text_version+1,
                                            strlen(dn)) != 0 ||
                                    ra->text_version[strlen(dn)+1] != '/') {
                                        free(dn);
                                        continue;
                                }
                                free(dn);
                                /* we have a match */
                                match = array_list;
                                if (verbose>0)
                                        fprintf(stderr, Name ": match found for member %s\n",
                                                array_list->member);
                                break;
                        }

                        if (match && match->devname &&
                            strcasecmp(match->devname, "<ignore>") == 0) {
                                if (verbose > 0)
                                        fprintf(stderr, Name ": array %s/%s is "
                                                "explicitly ignored by mdadm.conf\n",
                                                match->container, match->member);
                                return 2;
                        }

                        mdfd = create_mddev(match ? match->devname : NULL,
                                            ra->name,
                                            autof,
                                            trustworthy,
                                            chosen_name);
                }

                if (mdfd < 0) {
                        fprintf(stderr, Name ": failed to open %s: %s.\n",
                                chosen_name, strerror(errno));
                        return 2;
                }

                assemble_container_content(st, mdfd, ra, runstop,
                                           chosen_name, verbose);
        }
        map_unlock(&map);
        return 0;
}