Fix RAID metadata check

[thirdparty/mdadm.git] / super0.c

/*
 * mdadm - manage Linux "md" devices aka RAID arrays.
 *
 * Copyright (C) 2001-2009 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>
 */

#define HAVE_STDINT_H 1
#include "mdadm.h"
#include "sha1.h"
/*
 * All handling for the 0.90.0 version superblock is in
 * this file.
 * This includes:
 *   - finding, loading, and writing the superblock.
 *   - initialising a new superblock
 *   - printing the superblock for --examine
 *   - printing part of the superblock for --detail
 * .. other stuff
 */

static unsigned long calc_sb0_csum(mdp_super_t *super)
{
        unsigned long csum = super->sb_csum;
        unsigned long newcsum;
        super->sb_csum= 0 ;
        newcsum = calc_csum(super, MD_SB_BYTES);
        super->sb_csum = csum;
        return newcsum;
}

static void super0_swap_endian(struct mdp_superblock_s *sb)
{
        /* as super0 superblocks are host-endian, it is sometimes
         * useful to be able to swap the endianness
         * as (almost) everything is u32's we byte-swap every 4byte
         * number.
         * We then also have to swap the events_hi and events_lo
         */
        char *sbc = (char *)sb;
        __u32 t32;
        int i;

        for (i=0; i < MD_SB_BYTES ; i+=4) {
                char t = sbc[i];
                sbc[i] = sbc[i+3];
                sbc[i+3] = t;
                t=sbc[i+1];
                sbc[i+1]=sbc[i+2];
                sbc[i+2]=t;
        }
        t32 = sb->events_hi;
        sb->events_hi = sb->events_lo;
        sb->events_lo = t32;

        t32 = sb->cp_events_hi;
        sb->cp_events_hi = sb->cp_events_lo;
        sb->cp_events_lo = t32;

}

#ifndef MDASSEMBLE

static void examine_super0(struct supertype *st, char *homehost)
{
        mdp_super_t *sb = st->sb;
        time_t atime;
        int d;
        int delta_extra = 0;
        char *c;

        printf("          Magic : %08x\n", sb->md_magic);
        printf("        Version : %d.%02d.%02d\n",
               sb->major_version, sb->minor_version, sb->patch_version);
        if (sb->minor_version >= 90) {
                printf("           UUID : %08x:%08x:%08x:%08x", sb->set_uuid0,
                       sb->set_uuid1, sb->set_uuid2, sb->set_uuid3);
                if (homehost) {
                        char buf[20];
                        void *hash;

                        hash = sha1_buffer(homehost, strlen(homehost), buf);
                        if (memcmp(&sb->set_uuid2, hash, 8) == 0)
                                printf(" (local to host %s)", homehost);
                }
                printf("\n");
        } else
                printf("           UUID : %08x\n", sb->set_uuid0);

        if (sb->not_persistent)
                printf("           Eedk : not persistent\n");

        atime = sb->ctime;
        printf("  Creation Time : %.24s\n", ctime(&atime));
        c = map_num(pers, sb->level);
        printf("     Raid Level : %s\n", c?c:"-unknown-");
        if ((int)sb->level > 0) {
                int ddsks = 0, ddsks_denom = 1;
                printf("  Used Dev Size : %d%s\n", sb->size,
                       human_size((long long)sb->size<<10));
                switch(sb->level) {
                case 1:
                        ddsks=1;
                        break;
                case 4:
                case 5:
                        ddsks = sb->raid_disks - 1;
                        break;
                case 6:
                        ddsks = sb->raid_disks - 2;
                        break;
                case 10:
                        ddsks = sb->raid_disks;
                        ddsks_denom =
                                (sb->layout & 255) * ((sb->layout >> 8) & 255);
                }
                if (ddsks) {
                        long long asize = sb->size;
                        asize = (asize << 10) * ddsks / ddsks_denom;
                        printf("     Array Size : %llu%s\n",
                               asize >> 10,  human_size(asize));
                }
        }
        printf("   Raid Devices : %d\n", sb->raid_disks);
        printf("  Total Devices : %d\n", sb->nr_disks);
        printf("Preferred Minor : %d\n", sb->md_minor);
        printf("\n");
        if (sb->minor_version > 90 && (sb->reshape_position + 1) != 0) {
                printf("  Reshape pos'n : %llu%s\n",
                       (unsigned long long)sb->reshape_position / 2,
                       human_size((long long)sb->reshape_position << 9));
                if (sb->delta_disks) {
                        printf("  Delta Devices : %d", sb->delta_disks);
                        printf(" (%d->%d)\n", sb->raid_disks-sb->delta_disks,
                               sb->raid_disks);
                        if (((int)sb->delta_disks) < 0)
                                delta_extra = - sb->delta_disks;
                }
                if (sb->new_level != sb->level) {
                        c = map_num(pers, sb->new_level);
                        printf("      New Level : %s\n", c?c:"-unknown-");
                }
                if (sb->new_layout != sb->layout) {
                        if (sb->level == 5) {
                                c = map_num(r5layout, sb->new_layout);
                                printf("     New Layout : %s\n",
                                       c?c:"-unknown-");
                        }
                        if (sb->level == 6) {
                                c = map_num(r6layout, sb->new_layout);
                                printf("     New Layout : %s\n",
                                       c?c:"-unknown-");
                        }
                        if (sb->level == 10) {
                                printf("     New Layout : near=%d, %s=%d\n",
                                       sb->new_layout&255,
                                       (sb->new_layout&0x10000)?"offset":"far",
                                       (sb->new_layout>>8)&255);
                        }
                }
                if (sb->new_chunk != sb->chunk_size)
                        printf("  New Chunksize : %d\n", sb->new_chunk);
                printf("\n");
        }
        atime = sb->utime;
        printf("    Update Time : %.24s\n", ctime(&atime));
        printf("          State : %s\n",
               (sb->state&(1 << MD_SB_CLEAN)) ? "clean":"active");
        if (sb->state & (1 << MD_SB_BITMAP_PRESENT))
                printf("Internal Bitmap : present\n");
        printf(" Active Devices : %d\n", sb->active_disks);
        printf("Working Devices : %d\n", sb->working_disks);
        printf(" Failed Devices : %d\n", sb->failed_disks);
        printf("  Spare Devices : %d\n", sb->spare_disks);
        if (calc_sb0_csum(sb) == sb->sb_csum)
                printf("       Checksum : %x - correct\n", sb->sb_csum);
        else
                printf("       Checksum : %x - expected %lx\n",
                       sb->sb_csum, calc_sb0_csum(sb));
        printf("         Events : %llu\n",
               ((unsigned long long)sb->events_hi << 32) + sb->events_lo);
        printf("\n");
        if (sb->level == 5) {
                c = map_num(r5layout, sb->layout);
                printf("         Layout : %s\n", c?c:"-unknown-");
        }
        if (sb->level == 6) {
                c = map_num(r6layout, sb->layout);
                printf("         Layout : %s\n", c?c:"-unknown-");
        }
        if (sb->level == 10) {
                printf("         Layout :");
                print_r10_layout(sb->layout);
                printf("\n");
        }
        switch(sb->level) {
        case 0:
        case 4:
        case 5:
        case 6:
        case 10:
                printf("     Chunk Size : %dK\n", sb->chunk_size / 1024);
                break;
        case -1:
                printf("       Rounding : %dK\n", sb->chunk_size / 1024);
                break;
        default:
                break;
        }
        printf("\n");
        printf("      Number   Major   Minor   RaidDevice State\n");
        for (d = -1;
             d < (signed int)(sb->raid_disks + delta_extra + sb->spare_disks);
             d++) {
                mdp_disk_t *dp;
                char *dv;
                char nb[5];
                int wonly;
                if (d>=0) dp = &sb->disks[d];
                else dp = &sb->this_disk;
                snprintf(nb, sizeof(nb), "%4d", d);
                printf("%4s %5d   %5d    %5d    %5d     ", d < 0 ? "this" : nb,
                       dp->number, dp->major, dp->minor, dp->raid_disk);
                wonly = dp->state & (1 << MD_DISK_WRITEMOSTLY);
                dp->state &= ~(1 << MD_DISK_WRITEMOSTLY);
                if (dp->state & (1 << MD_DISK_FAULTY))
                        printf(" faulty");
                if (dp->state & (1 << MD_DISK_ACTIVE))
                        printf(" active");
                if (dp->state & (1 << MD_DISK_SYNC))
                        printf(" sync");
                if (dp->state & (1 << MD_DISK_REMOVED))
                        printf(" removed");
                if (wonly)
                        printf(" write-mostly");
                if (dp->state == 0)
                        printf(" spare");
                if ((dv = map_dev(dp->major, dp->minor, 0)))
                        printf("   %s", dv);
                printf("\n");
                if (d == -1)
                        printf("\n");
        }
}

static void brief_examine_super0(struct supertype *st, int verbose)
{
        mdp_super_t *sb = st->sb;
        char *c=map_num(pers, sb->level);
        char devname[20];

        sprintf(devname, "/dev/md%d", sb->md_minor);

        if (verbose) {
                printf("ARRAY %s level=%s num-devices=%d",
                       devname,
                       c?c:"-unknown-", sb->raid_disks);
        } else
                printf("ARRAY %s", devname);

        if (sb->minor_version >= 90)
                printf(" UUID=%08x:%08x:%08x:%08x", sb->set_uuid0, sb->set_uuid1,
                       sb->set_uuid2, sb->set_uuid3);
        else
                printf(" UUID=%08x", sb->set_uuid0);
        printf("\n");
}

static void export_examine_super0(struct supertype *st)
{
        mdp_super_t *sb = st->sb;

        printf("MD_LEVEL=%s\n", map_num(pers, sb->level));
        printf("MD_DEVICES=%d\n", sb->raid_disks);
        if (sb->minor_version >= 90)
                printf("MD_UUID=%08x:%08x:%08x:%08x\n",
                       sb->set_uuid0, sb->set_uuid1,
                       sb->set_uuid2, sb->set_uuid3);
        else
                printf("MD_UUID=%08x\n", sb->set_uuid0);
        printf("MD_UPDATE_TIME=%llu\n",
               __le64_to_cpu(sb->ctime) & 0xFFFFFFFFFFULL);
        printf("MD_EVENTS=%llu\n",
               ((unsigned long long)sb->events_hi << 32)
               + sb->events_lo);
}

static int copy_metadata0(struct supertype *st, int from, int to)
{
        /* Read 64K from the appropriate offset of 'from'
         * and if it looks a little like a 0.90 superblock,
         * write it to the same offset of 'to'
         */
        void *buf;
        unsigned long long dsize, offset;
        const int bufsize = 64*1024;
        mdp_super_t *super;

        if (posix_memalign(&buf, 4096, bufsize) != 0)
                return 1;

        if (!get_dev_size(from, NULL, &dsize))
                goto err;

        if (dsize < MD_RESERVED_SECTORS*512)
                goto err;

        offset = MD_NEW_SIZE_SECTORS(dsize>>9);

        offset *= 512;

        if (lseek64(from, offset, 0) < 0LL)
                goto err;
        if (read(from, buf, bufsize) != bufsize)
                goto err;

        if (lseek64(to, offset, 0) < 0LL)
                goto err;
        super = buf;
        if (super->md_magic != MD_SB_MAGIC ||
            super->major_version != 0 ||
            calc_sb0_csum(super) != super->sb_csum)
                goto err;
        if (write(to, buf, bufsize) != bufsize)
                goto err;
        free(buf);
        return 0;
err:
        free(buf);
        return 1;
}

static void detail_super0(struct supertype *st, char *homehost)
{
        mdp_super_t *sb = st->sb;
        printf("           UUID : ");
        if (sb->minor_version >= 90)
                printf("%08x:%08x:%08x:%08x", sb->set_uuid0, sb->set_uuid1,
                       sb->set_uuid2, sb->set_uuid3);
        else
                printf("%08x", sb->set_uuid0);
        if (homehost) {
                char buf[20];
                void *hash = sha1_buffer(homehost,
                                         strlen(homehost),
                                         buf);
                if (memcmp(&sb->set_uuid2, hash, 8)==0)
                        printf(" (local to host %s)", homehost);
        }
        printf("\n         Events : %d.%d\n\n", sb->events_hi, sb->events_lo);
}

static void brief_detail_super0(struct supertype *st)
{
        mdp_super_t *sb = st->sb;
        printf(" UUID=");
        if (sb->minor_version >= 90)
                printf("%08x:%08x:%08x:%08x", sb->set_uuid0, sb->set_uuid1,
                       sb->set_uuid2, sb->set_uuid3);
        else
                printf("%08x", sb->set_uuid0);
}
#endif

static int match_home0(struct supertype *st, char *homehost)
{
        mdp_super_t *sb = st->sb;
        char buf[20];
        char *hash;

        if (!homehost)
                return 0;
        hash = sha1_buffer(homehost,
                           strlen(homehost),
                           buf);

        return (memcmp(&sb->set_uuid2, hash, 8)==0);
}

static void uuid_from_super0(struct supertype *st, int uuid[4])
{
        mdp_super_t *super = st->sb;
        uuid[0] = super->set_uuid0;
        if (super->minor_version >= 90) {
                uuid[1] = super->set_uuid1;
                uuid[2] = super->set_uuid2;
                uuid[3] = super->set_uuid3;
        } else {
                uuid[1] = 0;
                uuid[2] = 0;
                uuid[3] = 0;
        }
}

static void getinfo_super0(struct supertype *st, struct mdinfo *info, char *map)
{
        mdp_super_t *sb = st->sb;
        int working = 0;
        int i;
        int map_disks = info->array.raid_disks;

        memset(info, 0, sizeof(*info));
        info->array.major_version = sb->major_version;
        info->array.minor_version = sb->minor_version;
        info->array.patch_version = sb->patch_version;
        info->array.raid_disks = sb->raid_disks;
        info->array.level = sb->level;
        info->array.layout = sb->layout;
        info->array.md_minor = sb->md_minor;
        info->array.ctime = sb->ctime;
        info->array.utime = sb->utime;
        info->array.chunk_size = sb->chunk_size;
        info->array.state = sb->state;
        info->component_size = sb->size;
        info->component_size *= 2;

        if (sb->state & (1<<MD_SB_BITMAP_PRESENT))
                info->bitmap_offset = 8;

        info->disk.state = sb->this_disk.state;
        info->disk.major = sb->this_disk.major;
        info->disk.minor = sb->this_disk.minor;
        info->disk.raid_disk = sb->this_disk.raid_disk;
        info->disk.number = sb->this_disk.number;

        info->events = md_event(sb);
        info->data_offset = 0;

        sprintf(info->text_version, "0.%d", sb->minor_version);
        info->safe_mode_delay = 200;

        uuid_from_super0(st, info->uuid);

        info->recovery_start = MaxSector;
        if (sb->minor_version > 90 && (sb->reshape_position+1) != 0) {
                info->reshape_active = 1;
                info->reshape_progress = sb->reshape_position;
                info->new_level = sb->new_level;
                info->delta_disks = sb->delta_disks;
                info->new_layout = sb->new_layout;
                info->new_chunk = sb->new_chunk;
                if (info->delta_disks < 0)
                        info->array.raid_disks -= info->delta_disks;
        } else
                info->reshape_active = 0;

        info->recovery_blocked = info->reshape_active;

        sprintf(info->name, "%d", sb->md_minor);
        /* work_disks is calculated rather than read directly */
        for (i=0; i < MD_SB_DISKS; i++)
                if ((sb->disks[i].state & (1<<MD_DISK_SYNC)) &&
                    (sb->disks[i].raid_disk < (unsigned)info->array.raid_disks) &&
                    (sb->disks[i].state & (1<<MD_DISK_ACTIVE)) &&
                    !(sb->disks[i].state & (1<<MD_DISK_FAULTY))) {
                        working ++;
                        if (map && i < map_disks)
                                map[i] = 1;
                } else if (map && i < map_disks)
                        map[i] = 0;
        info->array.working_disks = working;
}

static struct mdinfo *container_content0(struct supertype *st, char *subarray)
{
        struct mdinfo *info;

        if (subarray)
                return NULL;

        info = xmalloc(sizeof(*info));
        getinfo_super0(st, info, NULL);
        return info;
}

static int update_super0(struct supertype *st, struct mdinfo *info,
                         char *update,
                         char *devname, int verbose,
                         int uuid_set, char *homehost)
{
        /* NOTE: for 'assemble' and 'force' we need to return non-zero
         * if any change was made.  For others, the return value is
         * ignored.
         */
        int rv = 0;
        int uuid[4];
        mdp_super_t *sb = st->sb;

        if (strcmp(update, "homehost") == 0 &&
            homehost) {
                /* note that 'homehost' is special as it is really
                 * a "uuid" update.
                 */
                uuid_set = 0;
                update = "uuid";
                info->uuid[0] = sb->set_uuid0;
                info->uuid[1] = sb->set_uuid1;
        }

        if (strcmp(update, "sparc2.2")==0 ) {
                /* 2.2 sparc put the events in the wrong place
                 * So we copy the tail of the superblock
                 * up 4 bytes before continuing
                 */
                __u32 *sb32 = (__u32*)sb;
                memcpy(sb32+MD_SB_GENERIC_CONSTANT_WORDS+7,
                       sb32+MD_SB_GENERIC_CONSTANT_WORDS+7+1,
                       (MD_SB_WORDS - (MD_SB_GENERIC_CONSTANT_WORDS+7+1))*4);
                if (verbose >= 0)
                        pr_err("adjusting superblock of %s for 2.2/sparc compatibility.\n",
                               devname);
        } else if (strcmp(update, "super-minor") ==0) {
                sb->md_minor = info->array.md_minor;
                if (verbose > 0)
                        pr_err("updating superblock of %s with minor number %d\n",
                                devname, info->array.md_minor);
        } else if (strcmp(update, "summaries") == 0) {
                unsigned int i;
                /* set nr_disks, active_disks, working_disks,
                 * failed_disks, spare_disks based on disks[]
                 * array in superblock.
                 * Also make sure extra slots aren't 'failed'
                 */
                sb->nr_disks = sb->active_disks =
                        sb->working_disks = sb->failed_disks =
                        sb->spare_disks = 0;
                for (i=0; i < MD_SB_DISKS ; i++)
                        if (sb->disks[i].major ||
                            sb->disks[i].minor) {
                                int state = sb->disks[i].state;
                                if (state & (1<<MD_DISK_REMOVED))
                                        continue;
                                sb->nr_disks++;
                                if (state & (1<<MD_DISK_ACTIVE))
                                        sb->active_disks++;
                                if (state & (1<<MD_DISK_FAULTY))
                                        sb->failed_disks++;
                                else
                                        sb->working_disks++;
                                if (state == 0)
                                        sb->spare_disks++;
                        } else if (i >= sb->raid_disks && sb->disks[i].number == 0)
                                sb->disks[i].state = 0;
        } else if (strcmp(update, "force-one")==0) {
                /* Not enough devices for a working array, so
                 * bring this one up-to-date.
                 */
                __u32 ehi = sb->events_hi, elo = sb->events_lo;
                sb->events_hi = (info->events>>32) & 0xFFFFFFFF;
                sb->events_lo = (info->events) & 0xFFFFFFFF;
                if (sb->events_hi != ehi ||
                    sb->events_lo != elo)
                        rv = 1;
        } else if (strcmp(update, "force-array")==0) {
                /* degraded array and 'force' requested, so
                 * maybe need to mark it 'clean'
                 */
                if ((sb->level == 5 || sb->level == 4 || sb->level == 6) &&
                    (sb->state & (1 << MD_SB_CLEAN)) == 0) {
                        /* need to force clean */
                        sb->state |= (1 << MD_SB_CLEAN);
                        rv = 1;
                }
        } else if (strcmp(update, "assemble")==0) {
                int d = info->disk.number;
                int wonly = sb->disks[d].state & (1<<MD_DISK_WRITEMOSTLY);
                int mask = (1<<MD_DISK_WRITEMOSTLY);
                int add = 0;
                if (sb->minor_version >= 91)
                        /* During reshape we don't insist on everything
                         * being marked 'sync'
                         */
                        add = (1<<MD_DISK_SYNC);
                if (((sb->disks[d].state & ~mask) | add)
                    != (unsigned)info->disk.state) {
                        sb->disks[d].state = info->disk.state | wonly;
                        rv = 1;
                }
                if (info->reshape_active &&
                    sb->minor_version > 90 && (sb->reshape_position+1) != 0 &&
                    info->delta_disks >= 0 &&
                    info->reshape_progress < sb->reshape_position) {
                        sb->reshape_position = info->reshape_progress;
                        rv = 1;
                }
                if (info->reshape_active &&
                    sb->minor_version > 90 && (sb->reshape_position+1) != 0 &&
                    info->delta_disks < 0 &&
                    info->reshape_progress > sb->reshape_position) {
                        sb->reshape_position = info->reshape_progress;
                        rv = 1;
                }
        } else if (strcmp(update, "linear-grow-new") == 0) {
                memset(&sb->disks[info->disk.number], 0, sizeof(sb->disks[0]));
                sb->disks[info->disk.number].number = info->disk.number;
                sb->disks[info->disk.number].major = info->disk.major;
                sb->disks[info->disk.number].minor = info->disk.minor;
                sb->disks[info->disk.number].raid_disk = info->disk.raid_disk;
                sb->disks[info->disk.number].state = info->disk.state;
                sb->this_disk = sb->disks[info->disk.number];
        } else if (strcmp(update, "linear-grow-update") == 0) {
                sb->raid_disks = info->array.raid_disks;
                sb->nr_disks = info->array.nr_disks;
                sb->active_disks = info->array.active_disks;
                sb->working_disks = info->array.working_disks;
                memset(&sb->disks[info->disk.number], 0, sizeof(sb->disks[0]));
                sb->disks[info->disk.number].number = info->disk.number;
                sb->disks[info->disk.number].major = info->disk.major;
                sb->disks[info->disk.number].minor = info->disk.minor;
                sb->disks[info->disk.number].raid_disk = info->disk.raid_disk;
                sb->disks[info->disk.number].state = info->disk.state;
        } else if (strcmp(update, "resync") == 0) {
                /* make sure resync happens */
                sb->state &= ~(1<<MD_SB_CLEAN);
                sb->recovery_cp = 0;
        } else if (strcmp(update, "uuid") == 0) {
                if (!uuid_set && homehost) {
                        char buf[20];
                        char *hash = sha1_buffer(homehost,
                                                 strlen(homehost),
                                                 buf);
                        memcpy(info->uuid+2, hash, 8);
                }
                sb->set_uuid0 = info->uuid[0];
                sb->set_uuid1 = info->uuid[1];
                sb->set_uuid2 = info->uuid[2];
                sb->set_uuid3 = info->uuid[3];
                if (sb->state & (1<<MD_SB_BITMAP_PRESENT)) {
                        struct bitmap_super_s *bm;
                        bm = (struct bitmap_super_s*)(sb+1);
                        uuid_from_super0(st, uuid);
                        memcpy(bm->uuid, uuid, 16);
                }
        } else if (strcmp(update, "metadata") == 0) {
                /* Create some v1.0 metadata to match ours but make the
                 * ctime bigger.  Also update info->array.*_version.
                 * We need to arrange that store_super writes out
                 * the v1.0 metadata.
                 * Not permitted for unclean array, or array with
                 * bitmap.
                 */
                if (info->bitmap_offset) {
                        pr_err("Cannot update metadata when bitmap is present\n");
                        rv = -2;
                } else if (info->array.state != 1) {
                        pr_err("Cannot update metadata on unclean array\n");
                        rv = -2;
                } else {
                        info->array.major_version = 1;
                        info->array.minor_version = 0;
                        uuid_from_super0(st, info->uuid);
                        st->other = super1_make_v0(st, info, st->sb);
                }
        } else if (strcmp(update, "revert-reshape") == 0) {
                rv = -2;
                if (sb->minor_version <= 90)
                        pr_err("No active reshape to revert on %s\n",
                               devname);
                else if (sb->delta_disks == 0)
                        pr_err("%s: Can only revert reshape which changes number of devices\n",
                               devname);
                else {
                        int tmp;
                        int parity = sb->level == 6 ? 2 : 1;
                        rv = 0;

                        if (sb->level >= 4 && sb->level <= 6 &&
                            sb->reshape_position % (
                                    sb->new_chunk/512 *
                                    (sb->raid_disks - sb->delta_disks - parity))) {
                                pr_err("Reshape position is not suitably aligned.\n");
                                pr_err("Try normal assembly and stop again\n");
                                return -2;
                        }
                        sb->raid_disks -= sb->delta_disks;
                        sb->delta_disks = -sb->delta_disks;

                        tmp = sb->new_layout;
                        sb->new_layout = sb->layout;
                        sb->layout = tmp;

                        tmp = sb->new_chunk;
                        sb->new_chunk = sb->chunk_size;
                        sb->chunk_size = tmp;
                }
        } else if (strcmp(update, "no-bitmap") == 0) {
                sb->state &= ~(1<<MD_SB_BITMAP_PRESENT);
        } else if (strcmp(update, "_reshape_progress")==0)
                sb->reshape_position = info->reshape_progress;
        else if (strcmp(update, "writemostly")==0)
                sb->state |= (1<<MD_DISK_WRITEMOSTLY);
        else if (strcmp(update, "readwrite")==0)
                sb->state &= ~(1<<MD_DISK_WRITEMOSTLY);
        else
                rv = -1;

        sb->sb_csum = calc_sb0_csum(sb);
        return rv;
}

/*
 * For version-0 superblock, the homehost is 'stored' in the uuid.
 * 8 bytes for a hash of the host leaving 8 bytes of random material.
 * We use the first 8 bytes (64bits) of the sha1 of the host name
 */
static int init_super0(struct supertype *st, mdu_array_info_t *info,
                       unsigned long long size, char *ignored_name,
                       char *homehost, int *uuid,
                       unsigned long long data_offset)
{
        mdp_super_t *sb;
        int spares;

        if (data_offset != INVALID_SECTORS) {
                pr_err("data-offset not support for 0.90\n");
                return 0;
        }

        if (posix_memalign((void**)&sb, 4096,
                           MD_SB_BYTES + ROUND_UP(sizeof(bitmap_super_t), 4096)) != 0) {
                pr_err("could not allocate superblock\n");
                return 0;
        }
        memset(sb, 0, MD_SB_BYTES + sizeof(bitmap_super_t));

        st->sb = sb;
        if (info == NULL) {
                /* zeroing the superblock */
                return 0;
        }

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

        sb->md_magic = MD_SB_MAGIC;
        sb->major_version = 0;
        sb->minor_version = 90;
        sb->patch_version = 0;
        sb->gvalid_words = 0; /* ignored */
        sb->ctime = time(0);
        sb->level = info->level;
        sb->size = size;
        if (size != (unsigned long long)sb->size)
                return 0;
        sb->nr_disks = info->nr_disks;
        sb->raid_disks = info->raid_disks;
        sb->md_minor = info->md_minor;
        sb->not_persistent = 0;
        if (uuid) {
                sb->set_uuid0 = uuid[0];
                sb->set_uuid1 = uuid[1];
                sb->set_uuid2 = uuid[2];
                sb->set_uuid3 = uuid[3];
        } else {
                __u32 r[4];
                random_uuid((__u8 *)r);
                sb->set_uuid0 = r[0];
                sb->set_uuid1 = r[1];
                sb->set_uuid2 = r[2];
                sb->set_uuid3 = r[3];
        }
        if (homehost && !uuid) {
                char buf[20];
                char *hash = sha1_buffer(homehost,
                                         strlen(homehost),
                                         buf);
                memcpy(&sb->set_uuid2, hash, 8);
        }

        sb->utime = sb->ctime;
        sb->state = info->state;
        sb->active_disks = info->active_disks;
        sb->working_disks = info->working_disks;
        sb->failed_disks = info->failed_disks;
        sb->spare_disks = info->spare_disks;
        sb->events_hi = 0;
        sb->events_lo = 1;

        sb->layout = info->layout;
        sb->chunk_size = info->chunk_size;

        return 1;
}

struct devinfo {
        int fd;
        char *devname;
        mdu_disk_info_t disk;
        struct devinfo *next;
};

#ifndef MDASSEMBLE
/* Add a device to the superblock being created */
static int add_to_super0(struct supertype *st, mdu_disk_info_t *dinfo,
                         int fd, char *devname, unsigned long long data_offset)
{
        mdp_super_t *sb = st->sb;
        mdp_disk_t *dk = &sb->disks[dinfo->number];
        struct devinfo *di, **dip;

        dk->number = dinfo->number;
        dk->major = dinfo->major;
        dk->minor = dinfo->minor;
        dk->raid_disk = dinfo->raid_disk;
        dk->state = dinfo->state & ((1<<MD_DISK_ACTIVE) |
                                    (1<<MD_DISK_SYNC));

        sb->this_disk = sb->disks[dinfo->number];
        sb->sb_csum = calc_sb0_csum(sb);

        dip = (struct devinfo **)&st->info;
        while (*dip)
                dip = &(*dip)->next;
        di = xmalloc(sizeof(struct devinfo));
        di->fd = fd;
        di->devname = devname;
        di->disk = *dinfo;
        di->next = NULL;
        *dip = di;

        return 0;
}
#endif

static int store_super0(struct supertype *st, int fd)
{
        unsigned long long dsize;
        unsigned long long offset;
        mdp_super_t *super = st->sb;

        if (!get_dev_size(fd, NULL, &dsize))
                return 1;

        if (dsize < MD_RESERVED_SECTORS*512)
                return 2;

        if (st->other) {
                /* Writing out v1.0 metadata for --update=metadata */
                int ret = 0;

                offset = dsize/512 - 8*2;
                offset &= ~(4*2-1);
                offset *= 512;
                if (lseek64(fd, offset, 0)< 0LL)
                        ret = 3;
                else if (write(fd, st->other, 1024) != 1024)
                        ret = 4;
                else
                        fsync(fd);
                free(st->other);
                st->other = NULL;
                return ret;
        }

        offset = MD_NEW_SIZE_SECTORS(dsize>>9);

        offset *= 512;

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

        if (write(fd, super, sizeof(*super)) != sizeof(*super))
                return 4;

        if (super->state & (1<<MD_SB_BITMAP_PRESENT)) {
                struct bitmap_super_s * bm = (struct bitmap_super_s*)(super+1);
                if (__le32_to_cpu(bm->magic) == BITMAP_MAGIC)
                        if (write(fd, bm, ROUND_UP(sizeof(*bm),4096)) !=
                            ROUND_UP(sizeof(*bm),4096))
                            return 5;
        }

        fsync(fd);
        return 0;
}

#ifndef MDASSEMBLE
static int write_init_super0(struct supertype *st)
{
        mdp_super_t *sb = st->sb;
        int rv = 0;
        struct devinfo *di;

        for (di = st->info ; di && ! rv ; di = di->next) {

                if (di->disk.state & (1 << MD_DISK_FAULTY))
                        continue;
                if (di->fd == -1)
                        continue;
                while (Kill(di->devname, NULL, 0, -1, 1) == 0)
                        ;

                sb->disks[di->disk.number].state &= ~(1<<MD_DISK_FAULTY);

                sb->this_disk = sb->disks[di->disk.number];
                sb->sb_csum = calc_sb0_csum(sb);
                rv = store_super0(st, di->fd);

                if (rv == 0 && (sb->state & (1<<MD_SB_BITMAP_PRESENT)))
                        rv = st->ss->write_bitmap(st, di->fd, NoUpdate);

                if (rv)
                        pr_err("failed to write superblock to %s\n",
                               di->devname);
        }
        return rv;
}
#endif

static int compare_super0(struct supertype *st, struct supertype *tst)
{
        /*
         * return:
         *  0 same, or first was empty, and second was copied
         *  1 second had wrong number
         *  2 wrong uuid
         *  3 wrong other info
         */
        mdp_super_t *first = st->sb;
        mdp_super_t *second = tst->sb;
        int uuid1[4], uuid2[4];

        if (second->md_magic != MD_SB_MAGIC)
                return 1;
        if (!first) {
                if (posix_memalign((void**)&first, 4096,
                             MD_SB_BYTES +
                             ROUND_UP(sizeof(struct bitmap_super_s), 4096)) != 0) {
                        pr_err("could not allocate superblock\n");
                        return 1;
                }
                memcpy(first, second, MD_SB_BYTES + sizeof(struct bitmap_super_s));
                st->sb = first;
                return 0;
        }

        uuid_from_super0(st, uuid1);
        uuid_from_super0(tst, uuid2);
        if (!same_uuid(uuid1, uuid2, 0))
                return 2;
        if (first->major_version != second->major_version ||
            first->minor_version != second->minor_version ||
            first->patch_version != second->patch_version ||
            first->gvalid_words  != second->gvalid_words  ||
            first->ctime         != second->ctime         ||
            first->level         != second->level         ||
            first->size          != second->size          ||
            first->raid_disks    != second->raid_disks    )
                return 3;

        return 0;
}

static void free_super0(struct supertype *st);

static int load_super0(struct supertype *st, int fd, char *devname)
{
        /* try to read in the superblock
         * Return:
         *  0 on success
         *  1 on cannot get superblock
         *  2 on superblock meaningless
         */
        unsigned long long dsize;
        unsigned long long offset;
        mdp_super_t *super;
        int uuid[4];
        struct bitmap_super_s *bsb;

        free_super0(st);

        if (!get_dev_size(fd, devname, &dsize))
                return 1;

        if (dsize < MD_RESERVED_SECTORS*512) {
                if (devname)
                        pr_err("%s is too small for md: size is %llu sectors.\n",
                               devname, dsize);
                return 1;
        }
        st->devsize = dsize;

        offset = MD_NEW_SIZE_SECTORS(dsize>>9);

        offset *= 512;

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

        if (posix_memalign((void**)&super, 4096,
                           MD_SB_BYTES +
                           ROUND_UP(sizeof(bitmap_super_t), 4096)) != 0) {
                pr_err("could not allocate superblock\n");
                return 1;
        }

        if (read(fd, super, sizeof(*super)) != MD_SB_BYTES) {
                if (devname)
                        pr_err("Cannot read superblock on %s\n",
                                devname);
                free(super);
                return 1;
        }

        if (st->ss && st->minor_version == 9)
                super0_swap_endian(super);

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

        if (super->major_version != 0) {
                if (devname)
                        pr_err("Cannot interpret superblock on %s - version is %d\n",
                                devname, super->major_version);
                free(super);
                return 2;
        }
        st->sb = super;

        if (st->ss == NULL) {
                st->ss = &super0;
                st->minor_version = super->minor_version;
                st->max_devs = MD_SB_DISKS;
                st->info = NULL;
        }

        /* Now check on the bitmap superblock */
        if ((super->state & (1<<MD_SB_BITMAP_PRESENT)) == 0)
                return 0;
        /* Read the bitmap superblock and make sure it looks
         * valid.  If it doesn't clear the bit.  An --assemble --force
         * should get that written out.
         */
        if (read(fd, super+1, ROUND_UP(sizeof(struct bitmap_super_s),4096))
            != ROUND_UP(sizeof(struct bitmap_super_s),4096))
                goto no_bitmap;

        uuid_from_super0(st, uuid);
        bsb = (struct bitmap_super_s *)(super+1);
        if (__le32_to_cpu(bsb->magic) != BITMAP_MAGIC ||
            memcmp(bsb->uuid, uuid, 16) != 0)
                goto no_bitmap;
        return 0;

 no_bitmap:
        super->state &= ~(1<<MD_SB_BITMAP_PRESENT);

        return 0;
}

static struct supertype *match_metadata_desc0(char *arg)
{
        struct supertype *st = xcalloc(1, sizeof(*st));

        st->container_devnm[0] = 0;
        st->ss = &super0;
        st->info = NULL;
        st->minor_version = 90;
        st->max_devs = MD_SB_DISKS;
        st->sb = NULL;
        /* we sometimes get 00.90 */
        while (arg[0] == '0' && arg[1] == '0')
                arg++;
        if (strcmp(arg, "0") == 0 ||
#ifdef DEFAULT_OLD_METADATA /* ifndef in super1.c */
            strcmp(arg, "default") == 0 ||
#endif /* DEFAULT_OLD_METADATA */
            strcmp(arg, "0.90") == 0 ||
            strcmp(arg, "") == 0 /* no metadata  - i.e. non_persistent */
                )
                return st;

        st->minor_version = 91; /* reshape in progress */
        if (strcmp(arg, "0.91") == 0) /* For dup_super support */
                return st;

        st->minor_version = 9; /* flag for 'byte-swapped' */
        if (strcmp(arg, "0.swap")==0 ||
            strcmp(arg, "0.9") == 0) /* For dup_super support */
                return st;

        free(st);
        return NULL;
}

static __u64 avail_size0(struct supertype *st, __u64 devsize,
                         unsigned long long data_offset)
{
        if (data_offset != 0 && data_offset != INVALID_SECTORS)
                return 0ULL;
        if (devsize < MD_RESERVED_SECTORS)
                return 0ULL;
        return MD_NEW_SIZE_SECTORS(devsize);
}

static int add_internal_bitmap0(struct supertype *st, int *chunkp,
                                int delay, int write_behind,
                                unsigned long long size, int may_change,
                                int major)
{
        /*
         * The bitmap comes immediately after the superblock and must be 60K in size
         * at most.  The default size is between 30K and 60K
         *
         * size is in sectors,  chunk is in bytes !!!
         */
        unsigned long long bits;
        unsigned long long max_bits = (60*1024 - sizeof(bitmap_super_t))*8;
        unsigned long long min_chunk;
        int chunk = *chunkp;
        mdp_super_t *sb = st->sb;
        bitmap_super_t *bms = (bitmap_super_t*)(((char*)sb) + MD_SB_BYTES);
        int uuid[4];

        min_chunk = 4096; /* sub-page chunks don't work yet.. */
        bits = (size * 512) / min_chunk + 1;
        while (bits > max_bits) {
                min_chunk *= 2;
                bits = (bits+1)/2;
        }
        if (chunk == UnSet) {
                /* A chunk size less than a few Megabytes gives poor
                 * performance without increasing resync noticeably
                 */
                chunk = min_chunk;
                if (chunk < 64*1024*1024)
                        chunk = 64*1024*1024;
        } else if ((unsigned long long)chunk < min_chunk)
                return -EINVAL; /* chunk size too small */

        sb->state |= (1<<MD_SB_BITMAP_PRESENT);

        memset(bms, 0, sizeof(*bms));
        bms->magic = __cpu_to_le32(BITMAP_MAGIC);
        bms->version = __cpu_to_le32(major);
        uuid_from_super0(st, uuid);
        memcpy(bms->uuid, uuid, 16);
        bms->chunksize = __cpu_to_le32(chunk);
        bms->daemon_sleep = __cpu_to_le32(delay);
        bms->sync_size = __cpu_to_le64(size);
        bms->write_behind = __cpu_to_le32(write_behind);
        *chunkp = chunk;
        return 0;
}

static int locate_bitmap0(struct supertype *st, int fd, int node_num)
{
        unsigned long long dsize;
        unsigned long long offset;

        if (!get_dev_size(fd, NULL, &dsize))
                return -1;

        if (dsize < MD_RESERVED_SECTORS*512)
                return -1;

        offset = MD_NEW_SIZE_SECTORS(dsize>>9);

        offset *= 512;

        offset += MD_SB_BYTES;

        lseek64(fd, offset, 0);
        return 0;
}

static int write_bitmap0(struct supertype *st, int fd, enum bitmap_update update)
{
        unsigned long long dsize;
        unsigned long long offset;
        mdp_super_t *sb = st->sb;

        int rv = 0;

        int towrite, n;
        void *buf;

        if (!get_dev_size(fd, NULL, &dsize))
                return 1;

        if (dsize < MD_RESERVED_SECTORS*512)
                return -1;

        offset = MD_NEW_SIZE_SECTORS(dsize>>9);

        offset *= 512;

        if (lseek64(fd, offset + 4096, 0)< 0LL)
                return 3;

        if (posix_memalign(&buf, 4096, 4096))
                return -ENOMEM;

        memset(buf, 0xff, 4096);
        memcpy(buf,  ((char*)sb)+MD_SB_BYTES, sizeof(bitmap_super_t));
        towrite = 60*1024;
        while (towrite > 0) {
                n = towrite;
                if (n > 4096)
                        n = 4096;
                n = write(fd, buf, n);
                if (n > 0)
                        towrite -= n;
                else
                        break;
                memset(buf, 0xff, 4096);
        }
        fsync(fd);
        if (towrite)
                rv = -2;

        free(buf);
        return rv;
}

static void free_super0(struct supertype *st)
{
        if (st->sb)
                free(st->sb);
        while (st->info) {
                struct devinfo *di = st->info;
                st->info = di->next;
                if (di->fd >= 0)
                        close(di->fd);
                free(di);
        }
        st->sb = NULL;
}

#ifndef MDASSEMBLE
static int validate_geometry0(struct supertype *st, int level,
                              int layout, int raiddisks,
                              int *chunk, unsigned long long size,
                              unsigned long long data_offset,
                              char *subdev, unsigned long long *freesize,
                              int verbose)
{
        unsigned long long ldsize;
        int fd;
        unsigned int tbmax = 4;

        /* prior to linux 3.1, a but limits usable device size to 2TB.
         * It was introduced in 2.6.29, but we won't worry about that detail
         */
        if (get_linux_version() < 3001000)
                tbmax = 2;

        if (level == LEVEL_CONTAINER) {
                if (verbose)
                        pr_err("0.90 metadata does not support containers\n");
                return 0;
        }
        if (raiddisks > MD_SB_DISKS) {
                if (verbose)
                        pr_err("0.90 metadata supports at most %d devices per array\n",
                                MD_SB_DISKS);
                return 0;
        }
        if (size >= tbmax * 2ULL*1024*1024*1024) {
                if (verbose)
                        pr_err("0.90 metadata supports at most %d terabytes per device\n", tbmax);
                return 0;
        }
        if (*chunk == UnSet)
                *chunk = DEFAULT_CHUNK;

        if (!subdev)
                return 1;

        fd = open(subdev, O_RDONLY|O_EXCL, 0);
        if (fd < 0) {
                if (verbose)
                        pr_err("super0.90 cannot open %s: %s\n",
                                subdev, strerror(errno));
                return 0;
        }

        if (!get_dev_size(fd, subdev, &ldsize)) {
                close(fd);
                return 0;
        }
        close(fd);

        if (ldsize < MD_RESERVED_SECTORS * 512)
                return 0;
        *freesize = MD_NEW_SIZE_SECTORS(ldsize >> 9);
        return 1;
}
#endif /* MDASSEMBLE */

struct superswitch super0 = {
#ifndef MDASSEMBLE
        .examine_super = examine_super0,
        .brief_examine_super = brief_examine_super0,
        .export_examine_super = export_examine_super0,
        .detail_super = detail_super0,
        .brief_detail_super = brief_detail_super0,
        .write_init_super = write_init_super0,
        .validate_geometry = validate_geometry0,
        .add_to_super = add_to_super0,
        .copy_metadata = copy_metadata0,
#endif
        .match_home = match_home0,
        .uuid_from_super = uuid_from_super0,
        .getinfo_super = getinfo_super0,
        .container_content = container_content0,
        .update_super = update_super0,
        .init_super = init_super0,
        .store_super = store_super0,
        .compare_super = compare_super0,
        .load_super = load_super0,
        .match_metadata_desc = match_metadata_desc0,
        .avail_size = avail_size0,
        .add_internal_bitmap = add_internal_bitmap0,
        .locate_bitmap = locate_bitmap0,
        .write_bitmap = write_bitmap0,
        .free_super = free_super0,
        .name = "0.90",
};