Passes all tests, nearly ready for release.

[thirdparty/mdadm.git] / super1.c

/*
 * mdadm - manage Linux "md" devices aka RAID arrays.
 *
 * Copyright (C) 2001-2004 Neil Brown <neilb@cse.unsw.edu.au>
 *
 *
 *    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 <endian.h>
#include "asm/byteorder.h"
/*
 * The version-1 superblock :
 * All numeric fields are little-endian.
 *
 * total size: 256 bytes plus 2 per device.
 *  1K allows 384 devices.
 */
struct mdp_superblock_1 {
        /* constant array information - 128 bytes */
        __u32   magic;          /* MD_SB_MAGIC: 0xa92b4efc - little endian */
        __u32   major_version;  /* 1 */
        __u32   feature_map;    /* 0 for now */
        __u32   pad0;           /* always set to 0 when writing */

        __u8    set_uuid[16];   /* user-space generated. */
        char    set_name[32];   /* set and interpreted by user-space */

        __u64   ctime;          /* lo 40 bits are seconds, top 24 are microseconds or 0*/
        __u32   level;          /* -4 (multipath), -1 (linear), 0,1,4,5 */
        __u32   layout;         /* only for raid5 currently */
        __u64   size;           /* used size of component devices, in 512byte sectors */

        __u32   chunksize;      /* in 512byte sectors */
        __u32   raid_disks;
        __u32   bitmap_offset;  /* sectors after start of superblock that bitmap starts
                                 * NOTE: signed, so bitmap can be before superblock
                                 * only meaningful of feature_map[0] is set.
                                 */
        __u8    pad1[128-100];  /* set to 0 when written */

        /* constant this-device information - 64 bytes */
        __u64   data_offset;    /* sector start of data, often 0 */
        __u64   data_size;      /* sectors in this device that can be used for data */
        __u64   super_offset;   /* sector start of this superblock */
        __u64   recovery_offset;/* sectors before this offset (from data_offset) have been recovered */
        __u32   dev_number;     /* permanent identifier of this  device - not role in raid */
        __u32   cnt_corrected_read; /* number of read errors that were corrected by re-writing */
        __u8    device_uuid[16]; /* user-space setable, ignored by kernel */
        __u8    devflags;        /* per-device flags.  Only one defined...*/
#define WriteMostly1    1        /* mask for writemostly flag in above */
        __u8    pad2[64-57];    /* set to 0 when writing */

        /* array state information - 64 bytes */
        __u64   utime;          /* 40 bits second, 24 btes microseconds */
        __u64   events;         /* incremented when superblock updated */
        __u64   resync_offset;  /* data before this offset (from data_offset) known to be in sync */
        __u32   sb_csum;        /* checksum upto devs[max_dev] */
        __u32   max_dev;        /* size of devs[] array to consider */
        __u8    pad3[64-32];    /* set to 0 when writing */

        /* device state information. Indexed by dev_number.
         * 2 bytes per device
         * Note there are no per-device state flags. State information is rolled
         * into the 'roles' value.  If a device is spare or faulty, then it doesn't
         * have a meaningful role.
         */
        __u16   dev_roles[0];   /* role in array, or 0xffff for a spare, or 0xfffe for faulty */
};

#ifndef offsetof
#define offsetof(t,f) ((int)&(((t*)0)->f))
#endif
static unsigned int calc_sb_1_csum(struct mdp_superblock_1 * sb)
{
        unsigned int disk_csum, csum;
        unsigned long long newcsum;
        int size = sizeof(*sb) + __le32_to_cpu(sb->max_dev)*2;
        unsigned int *isuper = (unsigned int*)sb;
        int i;

/* make sure I can count... */
        if (offsetof(struct mdp_superblock_1,data_offset) != 128 ||
            offsetof(struct mdp_superblock_1, utime) != 192 ||
            sizeof(struct mdp_superblock_1) != 256) {
                fprintf(stderr, "WARNING - superblock isn't sized correctly\n");
        }

        disk_csum = sb->sb_csum;
        sb->sb_csum = 0;
        newcsum = 0;
        for (i=0; size>=4; size -= 4 )
                newcsum += __le32_to_cpu(*isuper++);

        if (size == 2)
                newcsum += __le16_to_cpu(*(unsigned short*) isuper);

        csum = (newcsum & 0xffffffff) + (newcsum >> 32);
        sb->sb_csum = disk_csum;
        return csum;
}

#ifndef MDASSEMBLE
static void examine_super1(void *sbv)
{
        struct mdp_superblock_1 *sb = sbv;
        time_t atime;
        int d;
        int faulty;
        int i;
        char *c;

        printf("          Magic : %08x\n", __le32_to_cpu(sb->magic));
        printf("        Version : %02d.%02d\n", 1, __le32_to_cpu(sb->feature_map));
        printf("     Array UUID : ");
        for (i=0; i<16; i++) {
                if ((i&3)==0 && i != 0) printf(":");
                printf("%02x", sb->set_uuid[i]);
        }
        printf("\n");
        printf("           Name : %.32s\n", sb->set_name);

        atime = __le64_to_cpu(sb->ctime) & 0xFFFFFFFFFFULL;
        printf("  Creation Time : %.24s\n", ctime(&atime));
        c=map_num(pers, __le32_to_cpu(sb->level));
        printf("     Raid Level : %s\n", c?c:"-unknown-");
        printf("   Raid Devices : %d\n", __le32_to_cpu(sb->raid_disks));
        printf("\n");
        printf("    Device Size : %llu%s\n", (unsigned long long)sb->data_size, human_size(sb->data_size<<9));
        if (sb->data_offset)
                printf("    Data Offset : %llu sectors\n", (unsigned long long)__le64_to_cpu(sb->data_offset));
        if (sb->super_offset)
                printf("   Super Offset : %llu sectors\n", (unsigned long long)__le64_to_cpu(sb->super_offset));
        printf("          State : %s\n", (__le64_to_cpu(sb->resync_offset)+1)? "active":"clean");
        printf("    Device UUID : ");
        for (i=0; i<16; i++) {
                if ((i&3)==0 && i != 0) printf(":");
                printf("%02x", sb->device_uuid[i]);
        }
        printf("\n");
        if (sb->devflags) {
                printf("      Flags :");
                if (sb->devflags & WriteMostly1)
                        printf(" write-mostly");
                printf("\n");
        }

        atime = __le64_to_cpu(sb->utime) & 0xFFFFFFFFFFULL;
        printf("    Update Time : %.24s\n", ctime(&atime));

        if (calc_sb_1_csum(sb) == sb->sb_csum)
                printf("       Checksum : %x - correct\n", __le32_to_cpu(sb->sb_csum));
        else
                printf("       Checksum : %x - expected %x\n", __le32_to_cpu(sb->sb_csum),
                       __le32_to_cpu(calc_sb_1_csum(sb)));
        printf("         Events : %llu\n", (unsigned long long)__le64_to_cpu(sb->events));
        printf("\n");
        if (__le32_to_cpu(sb->level) == 5) {
                c = map_num(r5layout, __le32_to_cpu(sb->layout));
                printf("         Layout : %s\n", c?c:"-unknown-");
        }
        switch(__le32_to_cpu(sb->level)) {
        case 0:
        case 4:
        case 5:
                printf("     Chunk Size : %dK\n", __le32_to_cpu(sb->chunksize/2));
                break;
        case -1:
                printf("       Rounding : %dK\n", __le32_to_cpu(sb->chunksize/2));
                break;
        default: break;
        }
        printf("\n");
        printf("   Array State : ");
        for (d=0; d<__le32_to_cpu(sb->raid_disks); d++) {
                int cnt = 0;
                int me = 0;
                int i;
                for (i=0; i< __le32_to_cpu(sb->max_dev); i++) {
                        int role = __le16_to_cpu(sb->dev_roles[i]);
                        if (role == d) {
                                if (i == __le32_to_cpu(sb->dev_number))
                                        me = 1;
                                cnt++;
                        }
                }
                if (cnt > 1) printf("?");
                else if (cnt == 1 && me) printf("U");
                else if (cnt == 1) printf("u");
                else printf ("_");
        }
        faulty = 0;
        for (i=0; i< __le32_to_cpu(sb->max_dev); i++) {
                int role = __le16_to_cpu(sb->dev_roles[i]);
                if (role == 0xFFFE)
                        faulty++;
        }
        if (faulty) printf(" %d failed", faulty);
        printf("\n");
}


static void brief_examine_super1(void *sbv)
{
        struct mdp_superblock_1 *sb = sbv;
        int i;

        char *c=map_num(pers, __le32_to_cpu(sb->level));

        printf("ARRAY /dev/?? level=%s metadata=1 num-devices=%d UUID=",
               c?c:"-unknown-", sb->raid_disks);
        for (i=0; i<16; i++) {
                printf("%02x", sb->set_uuid[i]);
                if ((i&3)==0 && i != 0) printf(":");
        }
        if (sb->set_name[0])
                printf(" name=%.32s", sb->set_name);
        printf("\n");
}

static void detail_super1(void *sbv)
{
        struct mdp_superblock_1 *sb = sbv;
        int i;

        printf("           Name : %.32s\n", sb->set_name);
        printf("           UUID : ");
        for (i=0; i<16; i++) {
                if ((i&3)==0 && i != 0) printf(":");
                printf("%02x", sb->set_uuid[i]);
        }
        printf("\n         Events : %llu\n\n", (unsigned long long)__le64_to_cpu(sb->events));
}

static void brief_detail_super1(void *sbv)
{
        struct mdp_superblock_1 *sb = sbv;
        int i;

        if (sb->set_name[0])
                printf(" name=%.32s", sb->set_name);
        printf(" UUID=");
        for (i=0; i<16; i++) {
                if ((i&3)==0 && i != 0) printf(":");
                printf("%02x", sb->set_uuid[i]);
        }
}

#endif

static void uuid_from_super1(int uuid[4], void * sbv)
{
        struct mdp_superblock_1 *super = sbv;
        char *cuuid = (char*)uuid;
        int i;
        for (i=0; i<16; i++)
                cuuid[i] = super->set_uuid[i];
}

static void getinfo_super1(struct mdinfo *info, mddev_ident_t ident, void *sbv)
{
        struct mdp_superblock_1 *sb = sbv;
        int working = 0;
        int i;
        int role;

        info->array.major_version = 1;
        info->array.minor_version = __le32_to_cpu(sb->feature_map);
        info->array.patch_version = 0;
        info->array.raid_disks = __le32_to_cpu(sb->raid_disks);
        info->array.level = __le32_to_cpu(sb->level);
        info->array.md_minor = -1;
        info->array.ctime = __le64_to_cpu(sb->ctime);

        info->disk.major = 0;
        info->disk.minor = 0;
        info->disk.number = __le32_to_cpu(sb->dev_number);
        if (__le32_to_cpu(sb->dev_number) >= __le32_to_cpu(sb->max_dev) ||
            __le32_to_cpu(sb->max_dev) > 512)
                role = 0xfffe;
        else
                role = __le16_to_cpu(sb->dev_roles[__le32_to_cpu(sb->dev_number)]);

        info->disk.raid_disk = -1;
        switch(role) {
        case 0xFFFF:
                info->disk.state = 2; /* spare: ACTIVE, not sync, not faulty */
                break;
        case 0xFFFE:
                info->disk.state = 1; /* faulty */
                break;
        default:
                info->disk.state = 6; /* active and in sync */
                info->disk.raid_disk = role;
        }
        info->events = __le64_to_cpu(sb->events);

        memcpy(info->uuid, sb->set_uuid, 16);

        strncpy(ident->name, sb->set_name, 32);
        ident->name[32] = 0;

        for (i=0; i< __le32_to_cpu(sb->max_dev); i++) {
                role = __le16_to_cpu(sb->dev_roles[i]);
                if (/*role == 0xFFFF || */role < info->array.raid_disks)
                        working++;
        }

        info->array.working_disks = working;
}

static int update_super1(struct mdinfo *info, void *sbv, char *update, char *devname, int verbose)
{
        int rv = 0;
        struct mdp_superblock_1 *sb = sbv;

        if (strcmp(update, "force")==0) {
                sb->events = __cpu_to_le32(info->events);
                switch(__le32_to_cpu(sb->level)) {
                case 5: case 4: case 6:
                        /* need to force clean */
                        sb->resync_offset = ~0ULL;
                }
        }
        if (strcmp(update, "assemble")==0) {
                int d = info->disk.number;
                int want;
                if (info->disk.state == 6)
                        want = __cpu_to_le32(info->disk.raid_disk);
                else
                        want = 0xFFFF;
                if (sb->dev_roles[d] != want) {
                        sb->dev_roles[d] = want;
                        rv = 1;
                }
        }
#if 0
        if (strcmp(update, "newdev") == 0) {
                int d = info->disk.number;
                memset(&sb->disks[d], 0, sizeof(sb->disks[d]));
                sb->disks[d].number = d;
                sb->disks[d].major = info->disk.major;
                sb->disks[d].minor = info->disk.minor;
                sb->disks[d].raid_disk = info->disk.raid_disk;
                sb->disks[d].state = info->disk.state;
                sb->this_disk = sb->disks[d];
        }
#endif
        if (strcmp(update, "grow") == 0) {
                sb->raid_disks = __cpu_to_le32(info->array.raid_disks);
                /* FIXME */
        }
        if (strcmp(update, "resync") == 0) {
                /* make sure resync happens */
                sb->resync_offset = ~0ULL;
        }

        sb->sb_csum = calc_sb_1_csum(sb);
        return rv;
}


static __u64 event_super1(void *sbv)
{
        struct mdp_superblock_1 *sb = sbv;
        return __le64_to_cpu(sb->events);
}

static int init_super1(struct supertype *st, void **sbp, mdu_array_info_t *info, char *name)
{
        struct mdp_superblock_1 *sb = malloc(1024 + sizeof(bitmap_super_t));
        int spares;
        int rfd;
        memset(sb, 0, 1024);

        if (info->major_version == -1)
                /* zeroing superblock */
                return 0;

        spares = info->working_disks - info->active_disks;
        if (info->raid_disks + spares  > 384) {
                fprintf(stderr, Name ": too many devices requested: %d+%d > %d\n",
                        info->raid_disks , spares, 384);
                return 0;
        }


        sb->magic = __cpu_to_le32(MD_SB_MAGIC);
        sb->major_version = __cpu_to_le32(1);
        sb->feature_map = 0;
        sb->pad0 = 0;

        if ((rfd = open("/dev/urandom", O_RDONLY)) < 0 ||
            read(rfd, sb->set_uuid, 16) != 16) {
                *(__u32*)(sb->set_uuid) = random();
                *(__u32*)(sb->set_uuid+4) = random();
                *(__u32*)(sb->set_uuid+8) = random();
                *(__u32*)(sb->set_uuid+12) = random();
        }
        if (rfd >= 0) close(rfd);

        memset(sb->set_name, 0, 32);
        strcpy(sb->set_name, name);

        sb->ctime = __cpu_to_le64((unsigned long long)time(0));
        sb->level = __cpu_to_le32(info->level);
        sb->layout = __cpu_to_le32(info->layout);
        sb->size = __cpu_to_le64(info->size*2ULL);
        sb->chunksize = __cpu_to_le32(info->chunk_size>>9);
        sb->raid_disks = __cpu_to_le32(info->raid_disks);

        sb->data_offset = __cpu_to_le64(0);
        sb->data_size = __cpu_to_le64(0);
        sb->super_offset = __cpu_to_le64(0);
        sb->recovery_offset = __cpu_to_le64(0);

        sb->utime = sb->ctime;
        sb->events = __cpu_to_le64(1);
        if (info->state & (1<<MD_SB_CLEAN))
                sb->resync_offset = ~0ULL;
        else
                sb->resync_offset = 0;
        sb->max_dev = __cpu_to_le32((1024- sizeof(struct mdp_superblock_1))/
                                    sizeof(sb->dev_roles[0]));
        memset(sb->pad3, 0, sizeof(sb->pad3));

        memset(sb->dev_roles, 0xff, 1024 - sizeof(struct mdp_superblock_1));

        *sbp = sb;
        return 1;
}

/* Add a device to the superblock being created */
static void add_to_super1(void *sbv, mdu_disk_info_t *dk)
{
        struct mdp_superblock_1 *sb = sbv;
        __u16 *rp = sb->dev_roles + dk->number;
        if ((dk->state & 6) == 6) /* active, sync */
                *rp = __cpu_to_le16(dk->raid_disk);
        else if ((dk->state & ~2) == 0) /* active or idle -> spare */
                *rp = 0xffff;
        else
                *rp = 0xfffe;
}

static int store_super1(struct supertype *st, int fd, void *sbv)
{
        struct mdp_superblock_1 *sb = sbv;
        unsigned long long sb_offset;
        int sbsize;
        long size;

        if (ioctl(fd, BLKGETSIZE, &size))
                return 1;


        if (size < 24)
                return 2;

        /*
         * Calculate the position of the superblock.
         * It is always aligned to a 4K boundary and
         * depending on minor_version, it can be:
         * 0: At least 8K, but less than 12K, from end of device
         * 1: At start of device
         * 2: 4K from start of device.
         */
        switch(st->minor_version) {
        case 0:
                sb_offset = size;
                sb_offset -= 8*2;
                sb_offset &= ~(4*2-1);
                break;
        case 1:
                sb_offset = 0;
                break;
        case 2:
                sb_offset = 4*2;
                break;
        default:
                return -EINVAL;
        }



        if (sb_offset != __le64_to_cpu(sb->super_offset) &&
            0 != __le64_to_cpu(sb->super_offset)
                ) {
                fprintf(stderr, Name ": internal error - sb_offset is wrong\n");
                abort();
        }

        if (lseek64(fd, sb_offset << 9, 0)< 0LL)
                return 3;

        sbsize = sizeof(*sb) + 2 * __le32_to_cpu(sb->max_dev);

        if (write(fd, sb, sbsize) != sbsize)
                return 4;

        fsync(fd);
        return 0;
}

static int load_super1(struct supertype *st, int fd, void **sbp, char *devname);

static int write_init_super1(struct supertype *st, void *sbv,
                             mdu_disk_info_t *dinfo, char *devname)
{
        struct mdp_superblock_1 *sb = sbv;
        struct mdp_superblock_1 *refsb = NULL;
        int fd = open(devname, O_RDWR | O_EXCL);
        int rfd;
        int rv;

        long size;
        long long sb_offset;


        if (fd < 0) {
                fprintf(stderr, Name ": Failed to open %s to write superblock\n",
                        devname);
                return -1;
        }

        sb->dev_number = __cpu_to_le32(dinfo->number);
        if (dinfo->state & (1<<MD_DISK_WRITEMOSTLY))
                sb->devflags |= WriteMostly1;

        if ((rfd = open("/dev/urandom", O_RDONLY)) < 0 ||
            read(rfd, sb->device_uuid, 16) != 16) {
                *(__u32*)(sb->device_uuid) = random();
                *(__u32*)(sb->device_uuid+4) = random();
                *(__u32*)(sb->device_uuid+8) = random();
                *(__u32*)(sb->device_uuid+12) = random();
        }
        if (rfd >= 0) close(rfd);
        sb->events = 0;

        if (load_super1(st, fd, (void**)&refsb, NULL)==0) {
                memcpy(sb->device_uuid, refsb->device_uuid, 16);
                if (memcmp(sb->set_uuid, refsb->set_uuid, 16)==0) {
                        /* same array, so preserve events and dev_number */
                        sb->events = refsb->events;
                        sb->dev_number = refsb->dev_number;
                }
                free(refsb);
        }

        if (ioctl(fd, BLKGETSIZE, &size)) {
                close(fd);
                return 1;
        }

        if (size < 24) {
                close(fd);
                return 2;
        }


        /*
         * Calculate the position of the superblock.
         * It is always aligned to a 4K boundary and
         * depending on minor_version, it can be:
         * 0: At least 8K, but less than 12K, from end of device
         * 1: At start of device
         * 2: 4K from start of device.
         */
        switch(st->minor_version) {
        case 0:
                sb_offset = size;
                sb_offset -= 8*2;
                sb_offset &= ~(4*2-1);
                sb->super_offset = __cpu_to_le64(sb_offset);
                sb->data_offset = __cpu_to_le64(0);
                sb->data_size = __cpu_to_le64(sb_offset);
                break;
        case 1:
                sb->super_offset = __cpu_to_le64(0);
                sb->data_offset = __cpu_to_le64(4*2); /* leave 4k for super and bitmap */
                sb->data_size = __cpu_to_le64(size - 4*2);
                break;
        case 2:
                sb_offset = 4*2;
                sb->super_offset = __cpu_to_le64(sb_offset);
                sb->data_offset = __cpu_to_le64(sb_offset+4*2);
                sb->data_size = __cpu_to_le64(size - 4*2 - 4*2);
                break;
        default:
                return -EINVAL;
        }


        sb->sb_csum = calc_sb_1_csum(sb);
        rv = store_super1(st, fd, sb);
        if (rv)
                fprintf(stderr, Name ": failed to write superblock to %s\n", devname);

        if (rv == 0 && (__le32_to_cpu(sb->feature_map) & 1))
                rv = st->ss->write_bitmap(st, fd, sbv);
        close(fd);
        return rv;
}

static int compare_super1(void **firstp, void *secondv)
{
        /*
         * return:
         *  0 same, or first was empty, and second was copied
         *  1 second had wrong number
         *  2 wrong uuid
         *  3 wrong other info
         */
        struct mdp_superblock_1 *first = *firstp;
        struct mdp_superblock_1 *second = secondv;

        if (second->magic != __cpu_to_le32(MD_SB_MAGIC))
                return 1;
        if (second->major_version != __cpu_to_le32(1))
                return 1;

        if (!first) {
                first = malloc(1024);
                memcpy(first, second, 1024);
                *firstp = first;
                return 0;
        }
        if (memcmp(first->set_uuid, second->set_uuid, 16)!= 0)
                return 2;

        if (first->ctime      != second->ctime     ||
            first->level      != second->level     ||
            first->layout     != second->layout    ||
            first->size       != second->size      ||
            first->chunksize  != second->chunksize ||
            first->raid_disks != second->raid_disks)
                return 3;
        return 0;
}

static int load_super1(struct supertype *st, int fd, void **sbp, char *devname)
{
        unsigned long size;
        unsigned long long sb_offset;
        struct mdp_superblock_1 *super;



        if (st->ss == NULL) {
                int bestvers = -1;
                __u64 bestctime = 0;
                /* guess... choose latest ctime */
                st->ss = &super1;
                for (st->minor_version = 0; st->minor_version <= 2 ; st->minor_version++) {
                        switch(load_super1(st, fd, sbp, devname)) {
                        case 0: super = *sbp;
                                if (bestvers == -1 ||
                                    bestctime < __le64_to_cpu(super->ctime)) {
                                        bestvers = st->minor_version;
                                        bestctime = __le64_to_cpu(super->ctime);
                                }
                                free(super);
                                *sbp = NULL;
                                break;
                        case 1: st->ss = NULL; return 1; /*bad device */
                        case 2: break; /* bad, try next */
                        }
                }
                if (bestvers != -1) {
                        int rv;
                        st->minor_version = bestvers;
                        st->ss = &super1;
                        st->max_devs = 384;
                        rv = load_super1(st, fd, sbp, devname);
                        if (rv) st->ss = NULL;
                        return rv;
                }
                st->ss = NULL;
                return 2;
        }
        if (ioctl(fd, BLKGETSIZE, &size)) {
                if (devname)
                        fprintf(stderr, Name ": cannot find device size for %s: %s\n",
                                devname, strerror(errno));
                return 1;
        }

        if (size < 24) {
                if (devname)
                        fprintf(stderr, Name ": %s is too small for md: size is %lu sectors.\n",
                                devname, size);
                return 1;
        }

        /*
         * Calculate the position of the superblock.
         * It is always aligned to a 4K boundary and
         * depeding on minor_version, it can be:
         * 0: At least 8K, but less than 12K, from end of device
         * 1: At start of device
         * 2: 4K from start of device.
         */
        switch(st->minor_version) {
        case 0:
                sb_offset = size;
                sb_offset -= 8*2;
                sb_offset &= ~(4*2-1);
                break;
        case 1:
                sb_offset = 0;
                break;
        case 2:
                sb_offset = 4*2;
                break;
        default:
                return -EINVAL;
        }

        ioctl(fd, BLKFLSBUF, 0); /* make sure we read current data */


        if (lseek64(fd, sb_offset << 9, 0)< 0LL) {
                if (devname)
                        fprintf(stderr, Name ": Cannot seek to superblock on %s: %s\n",
                                devname, strerror(errno));
                return 1;
        }

        super = malloc(1024 + sizeof(bitmap_super_t));

        if (read(fd, super, 1024) != 1024) {
                if (devname)
                        fprintf(stderr, Name ": Cannot read superblock on %s\n",
                                devname);
                free(super);
                return 1;
        }

        if (__le32_to_cpu(super->magic) != MD_SB_MAGIC) {
                if (devname)
                        fprintf(stderr, Name ": No super block found on %s (Expected magic %08x, got %08x)\n",
                                devname, MD_SB_MAGIC, __le32_to_cpu(super->magic));
                free(super);
                return 2;
        }

        if (__le32_to_cpu(super->major_version) != 1) {
                if (devname)
                        fprintf(stderr, Name ": Cannot interpret superblock on %s - version is %d\n",
                                devname, __le32_to_cpu(super->major_version));
                free(super);
                return 2;
        }
        if (__le64_to_cpu(super->super_offset) != sb_offset) {
                if (devname)
                        fprintf(stderr, Name ": No superblock found on %s (super_offset is wrong)\n",
                                devname);
                free(super);
                return 2;
        }
        *sbp = super;
        return 0;
}


static struct supertype *match_metadata_desc1(char *arg)
{
        struct supertype *st = malloc(sizeof(*st));
        if (!st) return st;

        st->ss = &super1;
        st->max_devs = 384;
        if (strcmp(arg, "1") == 0 ||
            strcmp(arg, "1.0") == 0) {
                st->minor_version = 0;
                return st;
        }
        if (strcmp(arg, "1.1") == 0) {
                st->minor_version = 1;
                return st;
        }
        if (strcmp(arg, "1.2") == 0) {
                st->minor_version = 2;
                return st;
        }

        free(st);
        return NULL;
}

/* find available size on device with this devsize, using
 * superblock type st, and reserving 'reserve' sectors for
 * a possible bitmap
 */
static __u64 avail_size1(struct supertype *st, __u64 devsize)
{
        if (devsize < 24)
                return 0;

        switch(st->minor_version) {
        case 0:
                /* at end */
                return ((devsize - 8*2 ) & ~(4*2-1));
        case 1:
                /* at start, 4K for superblock and possible bitmap */
                return devsize - 4*2;
        case 2:
                /* 4k from start, 4K for superblock and possible bitmap */
                return devsize - (4+4)*2;
        }
        return 0;
}

static int
add_internal_bitmap1(struct supertype *st, void *sbv,
                     int chunk, int delay, int write_behind, int *sizep, int may_change)
{
        /*
         * If not may_change, then this is a 'Grow', and the bitmap
         * must fit after the superblock.
         * If may_change, then this is create, and we can put the bitmap
         * before the superblock if we like, or may move the start.
         * For now, just squeeze the bitmap into 3k and don't change anything.
         *
         * size is in K,  chunk is in bytes !!!
         */

        unsigned long long size = *sizep;
        unsigned long long bits;
        unsigned long long max_bits = (3*512 - sizeof(bitmap_super_t)) * 8;
        unsigned long long min_chunk;
        struct mdp_superblock_1 *sb = sbv;
        bitmap_super_t *bms = (bitmap_super_t*)(((char*)sb) + 1024);

        if (st->minor_version && !may_change &&
            __le64_to_cpu(sb->data_offset) - __le64_to_cpu(sb->super_offset) < 8)
                return 0; /* doesn't fit */



        min_chunk = 4096; /* sub-page chunks don't work yet.. */
        bits = (size*1024)/min_chunk +1;
        while (bits > max_bits) {
                min_chunk *= 2;
                bits = (bits+1)/2;
        }
        if (chunk == UnSet)
                chunk = min_chunk;
        else if (chunk < min_chunk)
                return 0; /* chunk size too small */

        sb->bitmap_offset = __cpu_to_le32(2);

        sb->feature_map = __cpu_to_le32(__le32_to_cpu(sb->feature_map) | 1);
        memset(bms, sizeof(*bms), 0);
        bms->magic = __cpu_to_le32(BITMAP_MAGIC);
        bms->version = __cpu_to_le32(BITMAP_MAJOR);
        uuid_from_super1((int*)bms->uuid, sb);
        bms->chunksize = __cpu_to_le32(chunk);
        bms->daemon_sleep = __cpu_to_le32(delay);
        bms->sync_size = __cpu_to_le64(size<<1);
        bms->write_behind = __cpu_to_le32(write_behind);

        return 1;
}


void locate_bitmap1(struct supertype *st, int fd)
{
        unsigned long long offset;
        struct mdp_superblock_1 *sb;

        if (st->ss->load_super(st, fd, (void**)&sb, NULL))
                return; /* no error I hope... */
        offset = __le64_to_cpu(sb->super_offset);
        offset += (long) __le32_to_cpu(sb->bitmap_offset);

        lseek64(fd, offset<<9, 0);
}

int write_bitmap1(struct supertype *st, int fd, void *sbv)
{
        struct mdp_superblock_1 *sb = sbv;
        bitmap_super_t *bms = (bitmap_super_t*)(((char*)sb)+1024);
        int rv = 0;

        int towrite, n;
        char buf[4096];

        locate_bitmap1(st, fd);

        write(fd, ((char*)sb)+1024, sizeof(bitmap_super_t));
        towrite = __le64_to_cpu(bms->sync_size) / (__le32_to_cpu(bms->chunksize)>>9);
        towrite = (towrite+7) >> 3; /* bits to bytes */
        memset(buf, 0xff, sizeof(buf));
        while (towrite > 0) {
                n = towrite;
                if (n > sizeof(buf))
                        n = sizeof(buf);
                n = write(fd, buf, n);
                if (n > 0)
                        towrite -= n;
                else
                        break;
        }
        fsync(fd);
        if (towrite)
                rv = -2;

        return rv;
}

struct superswitch super1 = {
#ifndef MDASSEMBLE
        .examine_super = examine_super1,
        .brief_examine_super = brief_examine_super1,
        .detail_super = detail_super1,
        .brief_detail_super = brief_detail_super1,
#endif
        .uuid_from_super = uuid_from_super1,
        .getinfo_super = getinfo_super1,
        .update_super = update_super1,
        .event_super = event_super1,
        .init_super = init_super1,
        .add_to_super = add_to_super1,
        .store_super = store_super1,
        .write_init_super = write_init_super1,
        .compare_super = compare_super1,
        .load_super = load_super1,
        .match_metadata_desc = match_metadata_desc1,
        .avail_size = avail_size1,
        .add_internal_bitmap = add_internal_bitmap1,
        .locate_bitmap = locate_bitmap1,
        .write_bitmap = write_bitmap1,
        .major = 1,
#if __BYTE_ORDER == BIG_ENDIAN
        .swapuuid = 0,
#else
        .swapuuid = 1,
#endif
};