xfs: remove suport for filesystems without unwritten extent flag

[thirdparty/xfsprogs-dev.git] / repair / sb.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 */
#include "libfrog.h"
#include "libxfs.h"
#include "libxcmd.h"
#include "libxlog.h"
#include "agheader.h"
#include "globals.h"
#include "protos.h"
#include "err_protos.h"
#include "xfs_multidisk.h"

#define BSIZE   (1024 * 1024)

/*
 * copy the fields of a superblock that are present in primary and
 * secondaries -- preserve fields that are different in the primary.
 */
static void
copy_sb(xfs_sb_t *source, xfs_sb_t *dest)
{
        xfs_ino_t       rootino;
        xfs_ino_t       rbmino;
        xfs_ino_t       rsumino;
        xfs_ino_t       uquotino;
        xfs_ino_t       gquotino;
        xfs_ino_t       pquotino;
        uint16_t        versionnum;

        rootino = dest->sb_rootino;
        rbmino = dest->sb_rbmino;
        rsumino = dest->sb_rsumino;
        uquotino = dest->sb_uquotino;
        gquotino = dest->sb_gquotino;
        pquotino = dest->sb_pquotino;

        versionnum = dest->sb_versionnum;

        *dest = *source;

        dest->sb_rootino = rootino;
        dest->sb_rbmino = rbmino;
        dest->sb_rsumino = rsumino;
        dest->sb_uquotino = uquotino;
        dest->sb_gquotino = gquotino;
        dest->sb_pquotino = pquotino;

        dest->sb_versionnum = versionnum;

        /*
         * copy over version bits that are stamped into all
         * secondaries and cannot be changed at run time in
         * the primary superblock
         */
        if (xfs_sb_version_hasdalign(source))
                dest->sb_versionnum |= XFS_SB_VERSION_DALIGNBIT;
        dest->sb_versionnum |= XFS_SB_VERSION_EXTFLGBIT;

        /*
         * these are all supposed to be zero or will get reset anyway
         */
        dest->sb_icount = 0;
        dest->sb_ifree = 0;
        dest->sb_fdblocks = 0;
        dest->sb_frextents = 0;

        memset(source->sb_fname, 0, 12);
}

static int
verify_sb_blocksize(xfs_sb_t *sb)
{
        /* check to make sure blocksize is legal 2^N, 9 <= N <= 16 */
        if (sb->sb_blocksize == 0)
                return XR_BAD_BLOCKSIZE;
        if (sb->sb_blocklog < XFS_MIN_BLOCKSIZE_LOG ||
            sb->sb_blocklog > XFS_MAX_BLOCKSIZE_LOG)
                return XR_BAD_BLOCKLOG;
        if (sb->sb_blocksize != (1 << sb->sb_blocklog))
                return XR_BAD_BLOCKLOG;

        return 0;
}

/*
 * find a secondary superblock, copy it into the sb buffer.
 * start is the point to begin reading BSIZE bytes.
 * skip contains a byte-count of how far to advance for next read.
 */
static int
__find_secondary_sb(
        xfs_sb_t        *rsb,
        uint64_t        start,
        uint64_t        skip)
{
        xfs_off_t       off;
        xfs_sb_t        *sb;
        xfs_sb_t        bufsb;
        char            *c_bufsb;
        int             done;
        int             i;
        int             dirty;
        int             retval;
        int             bsize;

        sb = (xfs_sb_t *)memalign(libxfs_device_alignment(), BSIZE);
        if (!sb) {
                do_error(
        _("error finding secondary superblock -- failed to memalign buffer\n"));
                exit(1);
        }

        memset(&bufsb, 0, sizeof(xfs_sb_t));
        retval = 0;
        dirty = 0;
        bsize = 0;

        /*
         * skip first sector since we know that's bad
         */
        for (done = 0, off = start; !done ; off += skip)  {
                /*
                 * read disk 1 MByte at a time.
                 */
                if (lseek(x.dfd, off, SEEK_SET) != off)  {
                        done = 1;
                }

                if (!done && (bsize = read(x.dfd, sb, BSIZE)) <= 0)  {
                        done = 1;
                }

                do_warn(".");

                /*
                 * check the buffer 512 bytes at a time since
                 * we don't know how big the sectors really are.
                 */
                for (i = 0; !done && i < bsize; i += BBSIZE)  {
                        c_bufsb = (char *)sb + i;
                        libxfs_sb_from_disk(&bufsb, (xfs_dsb_t *)c_bufsb);

                        if (verify_sb(c_bufsb, &bufsb, 0) != XR_OK)
                                continue;

                        do_warn(_("found candidate secondary superblock...\n"));

                        /*
                         * found one.  now verify it by looking
                         * for other secondaries.
                         */
                        memmove(rsb, &bufsb, sizeof(xfs_sb_t));
                        rsb->sb_inprogress = 0;
                        copied_sunit = 1;

                        if (verify_set_primary_sb(rsb, 0, &dirty) == XR_OK)  {
                                do_warn(
                        _("verified secondary superblock...\n"));
                                done = 1;
                                retval = 1;
                        } else  {
                                do_warn(
                        _("unable to verify superblock, continuing...\n"));
                        }
                }
        }

        free(sb);
        return retval;
}

static int
guess_default_geometry(
        uint64_t                *agsize,
        uint64_t                *agcount,
        libxfs_init_t           *x)
{
        struct fs_topology      ft;
        int                     blocklog;
        uint64_t                dblocks;
        int                     multidisk;

        memset(&ft, 0, sizeof(ft));
        get_topology(x, &ft, 1);

        /*
         * get geometry from get_topology result.
         * Use default block size (2^12)
         */
        blocklog = 12;
        multidisk = ft.dswidth | ft.dsunit;
        dblocks = x->dsize >> (blocklog - BBSHIFT);
        calc_default_ag_geometry(blocklog, dblocks, multidisk,
                                 agsize, agcount);

        return blocklog;
}

int
find_secondary_sb(xfs_sb_t *rsb)
{
        int             retval = 0;
        uint64_t        agcount;
        uint64_t        agsize;
        uint64_t        skip;
        int             blocklog;

        /*
         * Attempt to find secondary sb with a coarse approach,
         * first trying agblocks and blocksize read from sb, providing
         * they're sane.
         */
        do_warn(_("\nattempting to find secondary superblock...\n"));

        if (verify_sb_blocksize(rsb) == 0) {
                skip = (uint64_t)rsb->sb_agblocks * rsb->sb_blocksize;
                if (skip >= XFS_AG_MIN_BYTES && skip <= XFS_AG_MAX_BYTES)
                        retval = __find_secondary_sb(rsb, skip, skip);
        }

        /* If that failed, retry coarse approach, using default geometry */
        if (!retval) {
                blocklog = guess_default_geometry(&agsize, &agcount, &x);
                skip = agsize << blocklog;
                retval = __find_secondary_sb(rsb, skip, skip);
        }

        /* If that failed, fall back to the brute force method */
        if (!retval)
                retval = __find_secondary_sb(rsb, XFS_AG_MIN_BYTES, BSIZE);

        return retval;
}

/*
 * Calculate what the inode alignment field ought to be based on internal
 * superblock info and determine if it is valid.
 *
 * For standard v5 superblocks, the inode alignment must either match
 * XFS_INODE_BIG_CLUSTER_SIZE or a multiple based on the inode size. For v5
 * superblocks with sparse inode chunks enabled, inode alignment must match the
 * inode chunk size.
 *
 * Return true if the alignment is valid, false otherwise.
 */
static bool
sb_validate_ino_align(struct xfs_sb *sb)
{
        xfs_extlen_t    align;

        if (!xfs_sb_version_hasalign(sb))
                return true;

        /* standard cluster size alignment is always valid */
        align = XFS_INODE_BIG_CLUSTER_SIZE >> sb->sb_blocklog;
        if (align == sb->sb_inoalignmt)
                return true;

        /* alignment scaled by inode size is v5 only for now */
        if (!xfs_sb_version_hascrc(sb))
                return false;

        align = (XFS_INODE_BIG_CLUSTER_SIZE *
                 sb->sb_inodesize / XFS_DINODE_MIN_SIZE) >> sb->sb_blocklog;
        if (align == sb->sb_inoalignmt)
                return true;

        /*
         * Sparse inodes requires inoalignmt to match full inode chunk size and
         * spino_align to match the scaled alignment (as calculated above).
         */
        if (xfs_sb_version_hassparseinodes(sb)) {
                if (align != sb->sb_spino_align)
                        return false;

                align = (sb->sb_inodesize * XFS_INODES_PER_CHUNK)
                        >> sb->sb_blocklog;
                if (align == sb->sb_inoalignmt)
                        return true;
        }

        return false;
}

/*
 * Validate the given log space.  Derived from xfs_log_mount, though we
 * can't validate the minimum log size until later.  We only do this
 * validation on V5 filesystems because the kernel doesn't reject malformed
 * log geometry on older revision filesystems.
 *
 * Returns false if the log is garbage.
 */
static bool
verify_sb_loginfo(
        struct xfs_sb   *sb)
{
        if (xfs_sb_version_hascrc(sb) &&
            (sb->sb_logblocks == 0 ||
             sb->sb_logblocks > XFS_MAX_LOG_BLOCKS ||
             ((unsigned long long)sb->sb_logblocks << sb->sb_blocklog) >
             XFS_MAX_LOG_BYTES))
                return false;

        if (sb->sb_logsunit > 1 && sb->sb_logsunit % sb->sb_blocksize)
                return false;

        return true;
}

/*
 * verify a superblock -- does not verify root inode #
 *      can only check that geometry info is internally
 *      consistent.  because of growfs, that's no guarantee
 *      of correctness (e.g. geometry may have changed)
 *
 * fields verified or consistency checked:
 *
 *                      sb_magicnum
 *
 *                      sb_versionnum
 *
 *                      sb_inprogress
 *
 *                      sb_blocksize    (as a group)
 *                      sb_blocklog
 *
 * geometry info -      sb_dblocks      (as a group)
 *                      sb_agcount
 *                      sb_agblocks
 *                      sb_agblklog
 *
 * inode info -         sb_inodesize    (x-checked with geo info)
 *                      sb_inopblock
 *
 * sector size info -
 *                      sb_sectsize
 *                      sb_sectlog
 *                      sb_logsectsize
 *                      sb_logsectlog
 *
 * not checked here -
 *                      sb_rootino
 *                      sb_fname
 *                      sb_fpack
 *                      sb_logstart
 *                      sb_uuid
 *
 *                      ALL real-time fields
 *                      final 4 summary counters
 */

int
verify_sb(char *sb_buf, xfs_sb_t *sb, int is_primary_sb)
{
        uint32_t        bsize;
        int             i;
        int             ret;

        /* check magic number and version number */

        if (sb->sb_magicnum != XFS_SB_MAGIC)
                return(XR_BAD_MAGIC);

        if (!xfs_sb_good_version(sb))
                return(XR_BAD_VERSION);

        /* does sb think mkfs really finished ? */

        if (is_primary_sb && sb->sb_inprogress == 1)
                return(XR_BAD_INPROGRESS);

        /*
         * before going *any further*, validate the sector size and if the
         * version says we should have CRCs enabled, validate that.
         */

        /* check to make sure sectorsize is legal 2^N, 9 <= N <= 15 */
        if (sb->sb_sectsize == 0)
                return(XR_BAD_SECT_SIZE_DATA);

        bsize = 1;
        for (i = 0; bsize < sb->sb_sectsize &&
                i < sizeof(sb->sb_sectsize) * NBBY; i++)  {
                bsize <<= 1;
        }

        if (i < XFS_MIN_SECTORSIZE_LOG || i > XFS_MAX_SECTORSIZE_LOG)
                return(XR_BAD_SECT_SIZE_DATA);

        /* check sb sectorsize field against sb sectlog field */
        if (i != sb->sb_sectlog)
                return(XR_BAD_SECT_SIZE_DATA);

        /* sector size in range - CRC check time */
        if (xfs_sb_version_hascrc(sb) &&
            !libxfs_verify_cksum(sb_buf, sb->sb_sectsize, XFS_SB_CRC_OFF))
                return XR_BAD_CRC;

        /* check to ensure blocksize and blocklog are legal */
        ret = verify_sb_blocksize(sb);
        if (ret != 0)
                return ret;

        /* sanity check ag count, size fields against data size field */

        if (sb->sb_dblocks == 0 ||
                sb->sb_dblocks > XFS_MAX_DBLOCKS(sb) ||
                sb->sb_dblocks < XFS_MIN_DBLOCKS(sb))
                return(XR_BAD_FS_SIZE_DATA);

        if (sb->sb_agblklog != (uint8_t)log2_roundup(sb->sb_agblocks))
                return(XR_BAD_FS_SIZE_DATA);

        if (sb->sb_inodesize < XFS_DINODE_MIN_SIZE                     ||
            sb->sb_inodesize > XFS_DINODE_MAX_SIZE                     ||
            sb->sb_inodelog < XFS_DINODE_MIN_LOG                       ||
            sb->sb_inodelog > XFS_DINODE_MAX_LOG                       ||
            sb->sb_inodesize != (1 << sb->sb_inodelog)                 ||
            sb->sb_logsunit > XLOG_MAX_RECORD_BSIZE                    ||
            sb->sb_inopblock != howmany(sb->sb_blocksize, sb->sb_inodesize) ||
            (sb->sb_blocklog - sb->sb_inodelog != sb->sb_inopblog))
                return XR_BAD_INO_SIZE_DATA;

        if (!verify_sb_loginfo(sb))
                return XR_BAD_LOG_GEOMETRY;

        if (xfs_sb_version_hassector(sb))  {

                /* check to make sure log sector is legal 2^N, 9 <= N <= 15 */

                if (sb->sb_logsectsize == 0)
                        return(XR_BAD_SECT_SIZE_DATA);

                bsize = 1;

                for (i = 0; bsize < sb->sb_logsectsize &&
                        i < sizeof(sb->sb_logsectsize) * NBBY; i++)  {
                        bsize <<= 1;
                }

                if (i < XFS_MIN_SECTORSIZE_LOG || i > XFS_MAX_SECTORSIZE_LOG)
                        return(XR_BAD_SECT_SIZE_DATA);

                /* check sb log sectorsize field against sb log sectlog field */

                if (i != sb->sb_logsectlog)
                        return(XR_BAD_SECT_SIZE_DATA);
        }

        /*
         * real-time extent size is always set
         */
        if (sb->sb_rextsize * sb->sb_blocksize > XFS_MAX_RTEXTSIZE)
                return(XR_BAD_RT_GEO_DATA);

        if (sb->sb_rextsize * sb->sb_blocksize < XFS_MIN_RTEXTSIZE)
                        return(XR_BAD_RT_GEO_DATA);

        if (sb->sb_rblocks == 0)  {
                if (sb->sb_rextents != 0)
                        return(XR_BAD_RT_GEO_DATA);

                if (sb->sb_rbmblocks != 0)
                        return(XR_BAD_RT_GEO_DATA);

                if (sb->sb_rextslog != 0)
                        return(XR_BAD_RT_GEO_DATA);

                if (sb->sb_frextents != 0)
                        return(XR_BAD_RT_GEO_DATA);
        } else  {
                /*
                 * if we have a real-time partition, sanity-check geometry
                 */
                if (sb->sb_rblocks / sb->sb_rextsize != sb->sb_rextents)
                        return(XR_BAD_RT_GEO_DATA);

                if (sb->sb_rextslog !=
                                libxfs_highbit32((unsigned int)sb->sb_rextents))
                        return(XR_BAD_RT_GEO_DATA);

                if (sb->sb_rbmblocks != (xfs_extlen_t) howmany(sb->sb_rextents,
                                                NBBY * sb->sb_blocksize))
                        return(XR_BAD_RT_GEO_DATA);
        }

        /*
         * verify correctness of inode alignment if it's there
         */
        if (!sb_validate_ino_align(sb))
                return(XR_BAD_INO_ALIGN);

        /*
         * verify max. % of inodes (sb_imax_pct)
         */
        if (sb->sb_imax_pct > 100)
                return(XR_BAD_INO_MAX_PCT);

        /*
         * verify stripe alignment fields if present
         */
        if (xfs_sb_version_hasdalign(sb)) {
                if ((!sb->sb_unit && sb->sb_width) ||
                    (sb->sb_unit && sb->sb_agblocks % sb->sb_unit))
                        return(XR_BAD_SB_UNIT);
                if ((sb->sb_unit && !sb->sb_width) ||
                    (sb->sb_width && sb->sb_unit && sb->sb_width % sb->sb_unit))
                        return(XR_BAD_SB_WIDTH);
        } else if (sb->sb_unit || sb->sb_width)
                return XR_BAD_SB_WIDTH;

        /* Directory block log */
        if (sb->sb_blocklog + sb->sb_dirblklog > XFS_MAX_BLOCKSIZE_LOG)
                return XR_BAD_DIR_SIZE_DATA;

        return(XR_OK);
}

void
write_primary_sb(xfs_sb_t *sbp, int size)
{
        xfs_dsb_t       *buf;

        if (no_modify)
                return;

        buf = memalign(libxfs_device_alignment(), size);
        if (buf == NULL) {
                do_error(_("failed to memalign superblock buffer\n"));
                return;
        }
        memset(buf, 0, size);

        if (lseek(x.dfd, 0LL, SEEK_SET) != 0LL) {
                free(buf);
                do_error(_("couldn't seek to offset 0 in filesystem\n"));
        }

        libxfs_sb_to_disk(buf, sbp);

        if (xfs_sb_version_hascrc(sbp))
                xfs_update_cksum((char *)buf, size, XFS_SB_CRC_OFF);

        if (write(x.dfd, buf, size) != size) {
                free(buf);
                do_error(_("primary superblock write failed!\n"));
        }

        free(buf);
}

/*
 * get a possible superblock -- checks for internal consistency
 */
int
get_sb(xfs_sb_t *sbp, xfs_off_t off, int size, xfs_agnumber_t agno)
{
        int error, rval;
        xfs_dsb_t *buf;

        buf = memalign(libxfs_device_alignment(), size);
        if (buf == NULL) {
                do_error(
        _("error reading superblock %u -- failed to memalign buffer\n"),
                        agno);
                exit(1);
        }
        memset(buf, 0, size);
        memset(sbp, 0, sizeof(*sbp));

        /* try and read it first */

        if (lseek(x.dfd, off, SEEK_SET) != off)  {
                do_warn(
        _("error reading superblock %u -- seek to offset %" PRId64 " failed\n"),
                        agno, off);
                free(buf);
                return(XR_EOF);
        }

        if ((rval = read(x.dfd, buf, size)) != size)  {
                error = errno;
                do_warn(
        _("superblock read failed, offset %" PRId64 ", size %d, ag %u, rval %d\n"),
                        off, size, agno, rval);
                do_error("%s\n", strerror(error));
        }
        libxfs_sb_from_disk(sbp, buf);

        rval = verify_sb((char *)buf, sbp, agno == 0);
        free(buf);
        return rval;
}

/* returns element on list with highest reference count */
static fs_geo_list_t *
get_best_geo(fs_geo_list_t *list)
{
        int cnt = 0;
        fs_geo_list_t *current, *rval = NULL;

        current = list;

        while (current != NULL)  {
                if (current->refs > cnt)  {
                        rval = current;
                        cnt = current->refs;
                }
                current = current->next;
        }

        return(rval);
}

/* adds geometry info to linked list.  returns (sometimes new) head of list */
static fs_geo_list_t *
add_geo(fs_geo_list_t *list, fs_geometry_t *geo_p, int index)
{
        fs_geo_list_t   *current = list;

        while (current != NULL)  {
                if (memcmp(geo_p, &current->geo, sizeof(fs_geometry_t)) == 0)  {
                        current->refs++;
                        return(list);
                }

                current = current->next;
        }

        if ((current = malloc(sizeof(fs_geo_list_t))) == NULL) {
                do_error(_("couldn't malloc geometry structure\n"));
                exit(1);
        }

        current->geo = *geo_p;
        current->refs = 1;
        current->next = list;
        current->index = index;

        return(current);
}

static void
free_geo(fs_geo_list_t *list)
{
        fs_geo_list_t   *next;
        fs_geo_list_t   *current;

        for (current = list; current != NULL; current = next)  {
                next = current->next;
                free(current);
        }
}

void
get_sb_geometry(fs_geometry_t *geo, xfs_sb_t *sbp)
{
        memset(geo, 0, sizeof(fs_geometry_t));

        /*
         * blindly set fields that we know are always good
         */
        geo->sb_blocksize = sbp->sb_blocksize;
        geo->sb_dblocks = sbp->sb_dblocks;
        geo->sb_rblocks = sbp->sb_rblocks;
        geo->sb_rextents = sbp->sb_rextents;
        geo->sb_logstart = sbp->sb_logstart;
        geo->sb_rextsize = sbp->sb_rextsize;
        geo->sb_agblocks = sbp->sb_agblocks;
        geo->sb_agcount = sbp->sb_agcount;
        geo->sb_rbmblocks = sbp->sb_rbmblocks;
        geo->sb_logblocks = sbp->sb_logblocks;
        geo->sb_sectsize = sbp->sb_sectsize;
        geo->sb_inodesize = sbp->sb_inodesize;

        if (xfs_sb_version_hasalign(sbp))
                geo->sb_ialignbit = 1;

        if (xfs_sb_version_hasdalign(sbp))
                geo->sb_salignbit = 1;

        geo->sb_extflgbit = 1;
        geo->sb_fully_zeroed = 1;
}

/*
 * the way to verify that a primary sb is consistent with the
 * filesystem is find the secondaries given the info in the
 * primary and compare the geometries in the secondaries against
 * the geometry indicated by the primary.
 *
 * returns 0 if ok, else error code (XR_EOF, XR_INSUFF_SEC_SB, etc).
 */
int
verify_set_primary_sb(xfs_sb_t          *rsb,
                        int             sb_index,
                        int             *sb_modified)
{
        xfs_off_t       off;
        fs_geometry_t   geo;
        xfs_sb_t        *sb;
        fs_geo_list_t   *list;
        fs_geo_list_t   *current;
        xfs_agnumber_t  agno;
        int             num_sbs;
        int             size;
        int             num_ok;
        int             retval;

        /*
         * We haven't been able to validate the sector size yet properly
         * (e.g. in the case of repairing an image in a file), so we need to
         * take into account sector mismatches and so use the maximum possible
         * sector size rather than the sector size in @rsb.
         */
        size = NUM_AGH_SECTS * (1 << (XFS_MAX_SECTORSIZE_LOG));
        list = NULL;
        num_ok = 0;
        *sb_modified = 0;
        num_sbs = rsb->sb_agcount;

        sb = (xfs_sb_t *) alloc_ag_buf(size);

        /*
         * put the primary sb geometry info onto the geometry list
         */
        get_sb_geometry(&geo, rsb);
        list = add_geo(list, &geo, sb_index);

        /*
         * scan the secondaries and check them off as we get them so we only
         * process each one once
         */
        for (agno = 1; agno < rsb->sb_agcount; agno++) {
                off = (xfs_off_t)agno * rsb->sb_agblocks << rsb->sb_blocklog;

                retval = get_sb(sb, off, size, agno);
                if (retval == XR_EOF)
                        goto out_free_list;

                if (retval == XR_OK) {
                        /*
                         * save away geometry info. don't bother checking the
                         * sb against the agi/agf as the odds of the sb being
                         * corrupted in a way that it is internally consistent
                         * but not consistent with the rest of the filesystem is
                         * really really low.
                         */
                        get_sb_geometry(&geo, sb);
                        list = add_geo(list, &geo, agno);
                        num_ok++;
                }
        }

        /*
         * see if we have enough superblocks to bother with
         */
        retval = 0;
        if (num_ok < num_sbs / 2) {
                retval = XR_INSUFF_SEC_SB;
                goto out_free_list;
        }

        current = get_best_geo(list);

        /*
         * check that enough sbs agree that we're willing to
         * go with this geometry.  if not, print out the
         * geometry and a message about the force option.
         */
        switch (num_sbs)  {
        case 2:
                /*
                 * If we only have two allocation groups, and the superblock
                 * in the second allocation group differs from the primary
                 * superblock we can't verify the geometry information.
                 * Warn the user about this situation and get out unless
                 * explicitly overridden.
                 */
                if (current->refs != 2)  {
                        if (!force_geo)  {
                                do_warn(
        _("Only two AGs detected and they do not match - "
          "cannot validate filesystem geometry.\n"
          "Use the -o force_geometry option to proceed.\n"));
                                exit(1);
                        }
                }
                goto out_free_list;
        case 1:
                /*
                 * If we only have a single allocation group there is no
                 * secondary superblock that we can use to verify the geometry
                 * information.  Warn the user about this situation and get
                 * out unless explicitly overridden.
                 */
                if (!force_geo)  {
                        do_warn(
        _("Only one AG detected - "
          "cannot validate filesystem geometry.\n"
          "Use the -o force_geometry option to proceed.\n"));
                        exit(1);
                }
                goto out_free_list;
        default:
                /*
                 * at least half of the probed superblocks have
                 * to agree.  if they don't, this fs is probably
                 * too far gone anyway considering the fact that
                 * XFS normally doesn't alter the secondary superblocks.
                 */
                if (current->refs < num_sbs / 2)  {
                        do_warn(
                _("Not enough matching superblocks - cannot proceed.\n"));
                        exit(1);
                }
        }

        /*
         * set the geometry into primary superblock if necessary.
         */

        if (current->index != sb_index)  {
                *sb_modified = 1;
                off = (xfs_off_t)current->index * current->geo.sb_agblocks
                        * current->geo.sb_blocksize;
                if (get_sb(sb, off, current->geo.sb_sectsize,
                                current->index) != XR_OK)
                        do_error(_("could not read superblock\n"));

                copy_sb(sb, rsb);

                /*
                 * turn off inprogress bit since this is the primary.
                 * also save away values that we need to ensure are
                 * consistent in the other secondaries.
                 */
                rsb->sb_inprogress = 0;
                sb_inoalignmt = sb->sb_inoalignmt;
                sb_unit = sb->sb_unit;
                sb_width = sb->sb_width;
        }

out_free_list:
        free_geo(list);
        free(sb);
        return retval;
}