/*      $OpenBSD: msdosfs_vfsops.c,v 1.99 2025/09/20 13:53:36 mpi Exp $ */
/*      $NetBSD: msdosfs_vfsops.c,v 1.48 1997/10/18 02:54:57 briggs Exp $       */

/*-
 * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank.
 * Copyright (C) 1994, 1995, 1997 TooLs GmbH.
 * All rights reserved.
 * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by TooLs GmbH.
 * 4. The name of TooLs GmbH may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
/*
 * Written by Paul Popelka (paulp@uts.amdahl.com)
 *
 * You can do anything you want with this software, just don't say you wrote
 * it, and don't remove this notice.
 *
 * This software is provided "as is".
 *
 * The author supplies this software to be publicly redistributed on the
 * understanding that the author is not responsible for the correct
 * functioning of this software in any circumstances and is not liable for
 * any damages caused by this software.
 *
 * October 1992
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/kernel.h>
#include <sys/vnode.h>
#include <sys/lock.h>
#include <sys/specdev.h> /* XXX */      /* defines v_rdev */
#include <sys/mount.h>
#include <sys/buf.h>
#include <sys/fcntl.h>
#include <sys/disklabel.h>
#include <sys/ioctl.h>
#include <sys/malloc.h>
#include <sys/dirent.h>
#include <sys/disk.h>
#include <sys/dkio.h>
#include <sys/stdint.h>

#include <msdosfs/bpb.h>
#include <msdosfs/bootsect.h>
#include <msdosfs/direntry.h>
#include <msdosfs/denode.h>
#include <msdosfs/msdosfsmount.h>
#include <msdosfs/fat.h>

int msdosfs_mount(struct mount *, const char *, void *, struct nameidata *,
                       struct proc *);
int msdosfs_start(struct mount *, int, struct proc *);
int msdosfs_unmount(struct mount *, int, struct proc *);
int msdosfs_root(struct mount *, struct vnode **);
int msdosfs_statfs(struct mount *, struct statfs *, struct proc *);
int msdosfs_sync(struct mount *, int, int, struct ucred *, struct proc *);
int msdosfs_fhtovp(struct mount *, struct fid *, struct vnode **);
int msdosfs_vptofh(struct vnode *, struct fid *);
int msdosfs_check_export(struct mount *mp, struct mbuf *nam,
                              int *extflagsp, struct ucred **credanonp);

int msdosfs_mountfs(struct vnode *, struct mount *, struct proc *,
                         struct msdosfs_args *);

int msdosfs_sync_vnode(struct vnode *, void *);

/*
 * mp - path - addr in user space of mount point (ie /usr or whatever)
 * data - addr in user space of mount params including the name of the block
 * special file to treat as a filesystem.
 */
int
msdosfs_mount(struct mount *mp, const char *path, void *data,
    struct nameidata *ndp, struct proc *p)
{
        struct vnode *devvp;      /* vnode for blk device to mount */
        struct msdosfs_args *args = data; /* will hold data from mount request */
        /* msdosfs specific mount control block */
        struct msdosfsmount *pmp = NULL;
        char fname[MNAMELEN];
        char fspec[MNAMELEN];
        int error, flags;

        /*
         * If updating, check whether changing from read-only to
         * read/write; if there is no device name, that's all we do.
         */
        if (mp->mnt_flag & MNT_UPDATE) {
                pmp = VFSTOMSDOSFS(mp);
                error = 0;
                if (!(pmp->pm_flags & MSDOSFSMNT_RONLY) &&
                    (mp->mnt_flag & MNT_RDONLY)) {
                        mp->mnt_flag &= ~MNT_RDONLY;
                        VFS_SYNC(mp, MNT_WAIT, 0, p->p_ucred, p);
                        mp->mnt_flag |= MNT_RDONLY;

                        flags = WRITECLOSE;
                        if (mp->mnt_flag & MNT_FORCE)
                                flags |= FORCECLOSE;
                        error = vflush(mp, NULL, flags);
                        if (!error) {
                                int force = 0;

                                pmp->pm_flags |= MSDOSFSMNT_RONLY;
                                /* may be not supported, ignore error */
                                VOP_IOCTL(pmp->pm_devvp, DIOCCACHESYNC,
                                    &force, FWRITE, FSCRED, p);
                        }
                }
                if (!error && (mp->mnt_flag & MNT_RELOAD))
                        /* not yet implemented */
                        error = EOPNOTSUPP;
                if (error)
                        return (error);
                if ((pmp->pm_flags & MSDOSFSMNT_RONLY) &&
                    (mp->mnt_flag & MNT_WANTRDWR))
                        pmp->pm_flags &= ~MSDOSFSMNT_RONLY;

                if (args && args->fspec == NULL) {
                        /*
                         * Process export requests.
                         */
                        return (vfs_export(mp, &pmp->pm_export,
                            &args->export_info));
                }
                if (args == NULL)
                        return (0);
        }

        /*
         * Not an update, or updating the name: look up the name
         * and verify that it refers to a sensible block device.
         */
        error = copyinstr(args->fspec, fspec, sizeof(fspec), NULL);
        if (error)
                goto error;

        if (disk_map(fspec, fname, sizeof(fname), DM_OPENBLCK) == -1)
                bcopy(fspec, fname, sizeof(fname));

        NDINIT(ndp, LOOKUP, FOLLOW, UIO_SYSSPACE, fname, p);
        if ((error = namei(ndp)) != 0)
                goto error;

        devvp = ndp->ni_vp;

        if (devvp->v_type != VBLK) {
                error = ENOTBLK;
                goto error_devvp;
        }
        if (major(devvp->v_rdev) >= nblkdev) {
                error = ENXIO;
                goto error_devvp;
        }

        if ((mp->mnt_flag & MNT_UPDATE) == 0)
                error = msdosfs_mountfs(devvp, mp, p, args);
        else {
                if (devvp != pmp->pm_devvp)
                        error = EINVAL; /* XXX needs translation */
                else
                        vrele(devvp);
        }
        if (error)
                goto error_devvp;

        pmp = VFSTOMSDOSFS(mp);
        pmp->pm_gid = args->gid;
        pmp->pm_uid = args->uid;
        pmp->pm_mask = args->mask;
        pmp->pm_flags |= args->flags & MSDOSFSMNT_MNTOPT;

        if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
                pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
        else if (!(pmp->pm_flags &
            (MSDOSFSMNT_SHORTNAME | MSDOSFSMNT_LONGNAME)))
                pmp->pm_flags |= MSDOSFSMNT_LONGNAME;

        if (pmp->pm_flags & MSDOSFSMNT_LONGNAME)
                mp->mnt_stat.f_namemax = WIN_MAXLEN;
        else
                mp->mnt_stat.f_namemax = 12;

        bzero(mp->mnt_stat.f_mntonname, MNAMELEN);
        strlcpy(mp->mnt_stat.f_mntonname, path, MNAMELEN);
        bzero(mp->mnt_stat.f_mntfromname, MNAMELEN);
        strlcpy(mp->mnt_stat.f_mntfromname, fname, MNAMELEN);
        bzero(mp->mnt_stat.f_mntfromspec, MNAMELEN);
        strlcpy(mp->mnt_stat.f_mntfromspec, fspec, MNAMELEN);
        bcopy(args, &mp->mnt_stat.mount_info.msdosfs_args, sizeof(*args));

#ifdef MSDOSFS_DEBUG
        printf("msdosfs_mount(): mp %p, pmp %p, inusemap %p\n", mp,
            pmp, pmp->pm_inusemap);
#endif

        return (0);

error_devvp:
        vrele(devvp);

error:
        return (error);
}

int
msdosfs_mountfs(struct vnode *devvp, struct mount *mp, struct proc *p,
    struct msdosfs_args *argp)
{
        struct msdosfsmount *pmp;
        struct buf *bp;
        dev_t dev = devvp->v_rdev;
        union bootsector *bsp;
        struct byte_bpb33 *b33;
        struct byte_bpb50 *b50;
        struct byte_bpb710 *b710;
        extern struct vnode *rootvp;
        u_int8_t SecPerClust;
        int     ronly, error, bmapsiz;
        uint32_t fat_max_clusters;

        /*
         * Disallow multiple mounts of the same device.
         * Disallow mounting of a device that is currently in use
         * (except for root, which might share swap device for miniroot).
         * Flush out any old buffers remaining from a previous use.
         */
        if ((error = vfs_mountedon(devvp)) != 0)
                return (error);
        if (vcount(devvp) > 1 && devvp != rootvp)
                return (EBUSY);
        vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
        error = vinvalbuf(devvp, V_SAVE, p->p_ucred, p, 0, INFSLP);
        VOP_UNLOCK(devvp);
        if (error)
                return (error);

        ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
        error = VOP_OPEN(devvp, ronly ? FREAD : FREAD|FWRITE, FSCRED, p);
        if (error)
                return (error);

        bp  = NULL; /* both used in error_exit */
        pmp = NULL;

        /*
         * Read the boot sector of the filesystem, and then check the
         * boot signature.  If not a dos boot sector then error out.
         */
        if ((error = bread(devvp, 0, 4096, &bp)) != 0)
                goto error_exit;
        bsp = (union bootsector *)bp->b_data;
        b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
        b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
        b710 = (struct byte_bpb710 *)bsp->bs710.bsBPB;

        pmp = malloc(sizeof *pmp, M_MSDOSFSMNT, M_WAITOK | M_ZERO);
        pmp->pm_mountp = mp;

        /*
         * Compute several useful quantities from the bpb in the
         * bootsector.  Copy in the dos 5 variant of the bpb then fix up
         * the fields that are different between dos 5 and dos 3.3.
         */
        SecPerClust = b50->bpbSecPerClust;
        pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec);
        pmp->pm_ResSectors = getushort(b50->bpbResSectors);
        pmp->pm_FATs = b50->bpbFATs;
        pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts);
        pmp->pm_Sectors = getushort(b50->bpbSectors);
        pmp->pm_FATsecs = getushort(b50->bpbFATsecs);
        pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack);
        pmp->pm_Heads = getushort(b50->bpbHeads);
        pmp->pm_Media = b50->bpbMedia;

        /* Determine the number of DEV_BSIZE blocks in a MSDOSFS sector */
        pmp->pm_BlkPerSec = pmp->pm_BytesPerSec / DEV_BSIZE;

        if (!pmp->pm_BytesPerSec || !SecPerClust) {
                error = EINVAL;
                goto error_exit;
        }

        if (pmp->pm_Sectors == 0) {
                pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
                pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
        } else {
                pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
                pmp->pm_HugeSectors = pmp->pm_Sectors;
        }

        if (pmp->pm_RootDirEnts == 0) {
                if (pmp->pm_Sectors || pmp->pm_FATsecs ||
                    getushort(b710->bpbFSVers)) {
                        error = EINVAL;
                        goto error_exit;
                }
                pmp->pm_fatmask = FAT32_MASK;
                pmp->pm_fatmult = 4;
                pmp->pm_fatdiv = 1;
                pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs);
                if (getushort(b710->bpbExtFlags) & FATMIRROR)
                        pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM;
                else
                        pmp->pm_flags |= MSDOSFS_FATMIRROR;
        } else
                pmp->pm_flags |= MSDOSFS_FATMIRROR;

        /*
         * More sanity checks:
         *      MSDOSFS sectors per cluster: >0 && power of 2
         *      MSDOSFS sector size: >= DEV_BSIZE && power of 2
         *      HUGE sector count: >0
         *      FAT sectors: >0
         */
        if ((SecPerClust == 0) || (SecPerClust & (SecPerClust - 1)) ||
            (pmp->pm_BytesPerSec < DEV_BSIZE) ||
            (pmp->pm_BytesPerSec & (pmp->pm_BytesPerSec - 1)) ||
            (pmp->pm_HugeSectors == 0) || (pmp->pm_FATsecs == 0) ||
            (SecPerClust * pmp->pm_BlkPerSec > MAXBSIZE / DEV_BSIZE)) {
                error = EINVAL;
                goto error_exit;
        }

        pmp->pm_HugeSectors *= pmp->pm_BlkPerSec;
        pmp->pm_HiddenSects *= pmp->pm_BlkPerSec;
        pmp->pm_FATsecs *= pmp->pm_BlkPerSec;
        pmp->pm_fatblk = pmp->pm_ResSectors * pmp->pm_BlkPerSec;
        SecPerClust *= pmp->pm_BlkPerSec;

        if (FAT32(pmp)) {
                pmp->pm_rootdirblk = getulong(b710->bpbRootClust);
                pmp->pm_firstcluster = pmp->pm_fatblk
                        + (pmp->pm_FATs * pmp->pm_FATsecs);
                pmp->pm_fsinfo = getushort(b710->bpbFSInfo) * pmp->pm_BlkPerSec;
        } else {
                pmp->pm_rootdirblk = pmp->pm_fatblk +
                        (pmp->pm_FATs * pmp->pm_FATsecs);
                pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry)
                                       + DEV_BSIZE - 1) / DEV_BSIZE;
                pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
        }

        pmp->pm_nmbrofclusters = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
            SecPerClust;
        pmp->pm_maxcluster = pmp->pm_nmbrofclusters + 1;
        pmp->pm_fatsize = pmp->pm_FATsecs * DEV_BSIZE;

        if (pmp->pm_fatmask == 0) {
                if (pmp->pm_maxcluster
                    <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) {
                        /*
                         * This will usually be a floppy disk. This size makes
                         * sure that one fat entry will not be split across
                         * multiple blocks.
                         */
                        pmp->pm_fatmask = FAT12_MASK;
                        pmp->pm_fatmult = 3;
                        pmp->pm_fatdiv = 2;
                } else {
                        pmp->pm_fatmask = FAT16_MASK;
                        pmp->pm_fatmult = 2;
                        pmp->pm_fatdiv = 1;
                }
        }
        if (FAT12(pmp))
                pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec;
        else
                pmp->pm_fatblocksize = MAXBSIZE;

        /*
         * We now have the number of sectors in each FAT, so can work
         * out how many clusters can be represented in a FAT.  Let's
         * make sure the file system doesn't claim to have more clusters
         * than this.
         *
         * We perform the calculation like we do to avoid integer overflow.
         *
         * This will give us a count of clusters.  They are numbered
         * from 0, so the max cluster value is one less than the value
         * we end up with.
         */
        fat_max_clusters = pmp->pm_fatsize / pmp->pm_fatmult;
        fat_max_clusters *= pmp->pm_fatdiv;
        if (pmp->pm_maxcluster >= fat_max_clusters) {
#ifndef SMALL_KERNEL
                printf("msdosfs: reducing max cluster to %d from %d "
                    "due to FAT size\n", fat_max_clusters - 1,
                    pmp->pm_maxcluster);
#endif
                pmp->pm_maxcluster = fat_max_clusters - 1;
        }

        pmp->pm_fatblocksec = pmp->pm_fatblocksize / DEV_BSIZE;
        pmp->pm_bnshift = ffs(DEV_BSIZE) - 1;

        /*
         * Compute mask and shift value for isolating cluster relative byte
         * offsets and cluster numbers from a file offset.
         */
        pmp->pm_bpcluster = SecPerClust * DEV_BSIZE;
        pmp->pm_crbomask = pmp->pm_bpcluster - 1;
        pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1;

        /*
         * Check for valid cluster size
         * must be a power of 2
         */
        if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) {
                error = EINVAL;
                goto error_exit;
        }

        /*
         * Release the bootsector buffer.
         */
        brelse(bp);
        bp = NULL;

        /*
         * Check FSInfo
         */
        if (pmp->pm_fsinfo) {
                struct fsinfo *fp;

                if ((error = bread(devvp, pmp->pm_fsinfo, fsi_size(pmp),
                    &bp)) != 0)
                        goto error_exit;
                fp = (struct fsinfo *)bp->b_data;
                if (!bcmp(fp->fsisig1, "RRaA", 4)
                    && !bcmp(fp->fsisig2, "rrAa", 4)
                    && !bcmp(fp->fsisig3, "\0\0\125\252", 4)
                    && !bcmp(fp->fsisig4, "\0\0\125\252", 4))
                        /* Valid FSInfo. */
                        ;
                else
                        pmp->pm_fsinfo = 0;
                /* XXX make sure this tiny buf doesn't come back in fillinusemap! */
                SET(bp->b_flags, B_INVAL);
                brelse(bp);
                bp = NULL;
        }

        /*
         * Check and validate (or perhaps invalidate?) the fsinfo structure? XXX
         */

        /*
         * Allocate memory for the bitmap of allocated clusters, and then
         * fill it in.
         */
        bmapsiz = howmany(pmp->pm_maxcluster + 1, N_INUSEBITS);
        if (bmapsiz == 0 || SIZE_MAX / bmapsiz < sizeof(*pmp->pm_inusemap)) {
                /* detect multiplicative integer overflow */
                error = EINVAL;
                goto error_exit;
        }
        pmp->pm_inusemap = mallocarray(bmapsiz, sizeof(*pmp->pm_inusemap),
            M_MSDOSFSFAT, M_WAITOK | M_CANFAIL);
        if (pmp->pm_inusemap == NULL) {
                error = EINVAL;
                goto error_exit;
        }

        /*
         * fillinusemap() needs pm_devvp.
         */
        pmp->pm_dev = dev;
        pmp->pm_devvp = devvp;

        /*
         * Have the inuse map filled in.
         */
        if ((error = fillinusemap(pmp)) != 0)
                goto error_exit;

        /*
         * If they want fat updates to be synchronous then let them suffer
         * the performance degradation in exchange for the on disk copy of
         * the fat being correct just about all the time.  I suppose this
         * would be a good thing to turn on if the kernel is still flakey.
         */
        if (mp->mnt_flag & MNT_SYNCHRONOUS)
                pmp->pm_flags |= MSDOSFSMNT_WAITONFAT;

        /*
         * Finish up.
         */
        if (ronly)
                pmp->pm_flags |= MSDOSFSMNT_RONLY;
        else
                pmp->pm_fmod = 1;
        mp->mnt_data = pmp;
        mp->mnt_stat.f_fsid.val[0] = (long)dev;
        mp->mnt_stat.f_fsid.val[1] = mp->mnt_vfc->vfc_typenum;
#ifdef QUOTA
        /*
         * If we ever do quotas for DOS filesystems this would be a place
         * to fill in the info in the msdosfsmount structure. You dolt,
         * quotas on dos filesystems make no sense because files have no
         * owners on dos filesystems. of course there is some empty space
         * in the directory entry where we could put uid's and gid's.
         */
#endif
        devvp->v_specmountpoint = mp;

        return (0);

error_exit:
        if (devvp->v_specinfo)
                devvp->v_specmountpoint = NULL;
        if (bp)
                brelse(bp);

        vn_lock(devvp, LK_EXCLUSIVE|LK_RETRY);
        (void) VOP_CLOSE(devvp, ronly ? FREAD : FREAD|FWRITE, NOCRED, p);
        VOP_UNLOCK(devvp);

        if (pmp) {
                if (pmp->pm_inusemap)
                        free(pmp->pm_inusemap, M_MSDOSFSFAT, 0);
                free(pmp, M_MSDOSFSMNT, 0);
                mp->mnt_data = NULL;
        }
        return (error);
}

int
msdosfs_start(struct mount *mp, int flags, struct proc *p)
{

        return (0);
}

/*
 * Unmount the filesystem described by mp.
 */
int
msdosfs_unmount(struct mount *mp, int mntflags,struct proc *p)
{
        struct msdosfsmount *pmp;
        int error, flags;
        struct vnode *vp;

        flags = 0;
        if (mntflags & MNT_FORCE)
                flags |= FORCECLOSE;
        if ((error = vflush(mp, NULL, flags)) != 0)
                return (error);
        pmp = VFSTOMSDOSFS(mp);
        pmp->pm_devvp->v_specmountpoint = NULL;
        vp = pmp->pm_devvp;
#if defined(MSDOSFS_DEBUG) && (defined(DEBUG) || defined(DIAGNOSTIC))
        vprint("msdosfs_umount(): just before calling VOP_CLOSE()\n", vp);
#endif
        vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
        (void)VOP_CLOSE(vp,
            pmp->pm_flags & MSDOSFSMNT_RONLY ? FREAD : FREAD|FWRITE, NOCRED, p);
        vput(vp);
        free(pmp->pm_inusemap, M_MSDOSFSFAT, 0);
        free(pmp, M_MSDOSFSMNT, 0);
        mp->mnt_data = NULL;
        mp->mnt_flag &= ~MNT_LOCAL;
        return (0);
}

int
msdosfs_root(struct mount *mp, struct vnode **vpp)
{
        struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
        struct denode *ndep;
        int error;

        if ((error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep)) != 0)
                return (error);

#ifdef MSDOSFS_DEBUG
        printf("msdosfs_root(); mp %p, pmp %p, ndep %p, vp %p\n",
            mp, pmp, ndep, DETOV(ndep));
#endif

        *vpp = DETOV(ndep);
        return (0);
}

int
msdosfs_statfs(struct mount *mp, struct statfs *sbp, struct proc *p)
{
        struct msdosfsmount *pmp;

        pmp = VFSTOMSDOSFS(mp);
        sbp->f_bsize = pmp->pm_bpcluster;
        sbp->f_iosize = pmp->pm_bpcluster;
        sbp->f_blocks = pmp->pm_nmbrofclusters;
        sbp->f_bfree = pmp->pm_freeclustercount;
        sbp->f_bavail = pmp->pm_freeclustercount;
        sbp->f_files = pmp->pm_RootDirEnts;                     /* XXX */
        sbp->f_ffree = sbp->f_favail = 0;       /* what to put in here? */
        copy_statfs_info(sbp, mp);

        return (0);
}


struct msdosfs_sync_arg {
        struct proc *p;
        struct ucred *cred;
        int allerror;
        int waitfor;
};

int
msdosfs_sync_vnode(struct vnode *vp, void *arg)
{
        struct msdosfs_sync_arg *msa = arg;
        struct denode *dep;
        int error;
        int s, skip = 0;

        dep = VTODE(vp);
        s = splbio();
        if (vp->v_type == VNON ||
            ((dep->de_flag & (DE_ACCESS | DE_CREATE | DE_UPDATE | DE_MODIFIED)) == 0
              && LIST_EMPTY(&vp->v_dirtyblkhd)) ||
            msa->waitfor == MNT_LAZY) {
                skip = 1;
        }
        splx(s);

        if (skip)
                return (0);

        if (vget(vp, LK_EXCLUSIVE | LK_NOWAIT))
                return (0);

        if ((error = VOP_FSYNC(vp, msa->cred, msa->waitfor, msa->p)) != 0)
                msa->allerror = error;
        VOP_UNLOCK(vp);
        vrele(vp);

        return (0);
}


int
msdosfs_sync(struct mount *mp, int waitfor, int stall, struct ucred *cred,
    struct proc *p)
{
        struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
        struct msdosfs_sync_arg msa;
        int error;

        msa.allerror = 0;
        msa.p = p;
        msa.cred = cred;
        msa.waitfor = waitfor;

        /*
         * If we ever switch to not updating all of the fats all the time,
         * this would be the place to update them from the first one.
         */
        if (pmp->pm_fmod != 0) {
                if (pmp->pm_flags & MSDOSFSMNT_RONLY)
                        panic("msdosfs_sync: rofs mod");
                else {
                        /* update fats here */
                }
        }
        /*
         * Write back each (modified) denode.
         */
        vfs_mount_foreach_vnode(mp, msdosfs_sync_vnode, &msa);

        /*
         * Force stale file system control information to be flushed.
         */
        if (waitfor != MNT_LAZY) {
                vn_lock(pmp->pm_devvp, LK_EXCLUSIVE | LK_RETRY);
                if ((error = VOP_FSYNC(pmp->pm_devvp, cred, waitfor, p)) != 0)
                        msa.allerror = error;
                VOP_UNLOCK(pmp->pm_devvp);
        }

        return (msa.allerror);
}

int
msdosfs_fhtovp(struct mount *mp, struct fid *fhp, struct vnode **vpp)
{
        struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
        struct defid *defhp = (struct defid *) fhp;
        struct denode *dep;
        int error;

        error = deget(pmp, defhp->defid_dirclust, defhp->defid_dirofs, &dep);
        if (error) {
                *vpp = NULL;
                return (error);
        }
        *vpp = DETOV(dep);
        return (0);
}

int
msdosfs_vptofh(struct vnode *vp, struct fid *fhp)
{
        struct denode *dep;
        struct defid *defhp;

        dep = VTODE(vp);
        defhp = (struct defid *)fhp;
        defhp->defid_len = sizeof(struct defid);
        defhp->defid_dirclust = dep->de_dirclust;
        defhp->defid_dirofs = dep->de_diroffset;
        /* defhp->defid_gen = dep->de_gen; */
        return (0);
}

int
msdosfs_check_export(struct mount *mp, struct mbuf *nam, int *exflagsp,
    struct ucred **credanonp)
{
        struct netcred *np;
        struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);

        /*
         * Get the export permission structure for this <mp, client> tuple.
         */
        np = vfs_export_lookup(mp, &pmp->pm_export, nam);
        if (np == NULL)
                return (EACCES);

        *exflagsp = np->netc_exflags;
        *credanonp = &np->netc_anon;
        return (0);
}

const struct vfsops msdosfs_vfsops = {
        .vfs_mount      = msdosfs_mount,
        .vfs_start      = msdosfs_start,
        .vfs_unmount    = msdosfs_unmount,
        .vfs_root       = msdosfs_root,
        .vfs_quotactl   = (void *)eopnotsupp,
        .vfs_statfs     = msdosfs_statfs,
        .vfs_sync       = msdosfs_sync,
        .vfs_vget       = (void *)eopnotsupp,
        .vfs_fhtovp     = msdosfs_fhtovp,
        .vfs_vptofh     = msdosfs_vptofh,
        .vfs_init       = msdosfs_init,
        .vfs_sysctl     = (void *)eopnotsupp,
        .vfs_checkexp   = msdosfs_check_export,
};