/*      $OpenBSD: udf_vfsops.c,v 1.73 2025/09/20 13:53:36 mpi Exp $     */

/*
 * Copyright (c) 2001, 2002 Scott Long <scottl@freebsd.org>
 * All rights reserved.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 THE AUTHOR OR CONTRIBUTORS 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.
 *
 * $FreeBSD: src/sys/fs/udf/udf_vfsops.c,v 1.25 2005/01/25 15:52:03 phk Exp $
 */

/*
 * Ported to OpenBSD by Pedro Martelletto in February 2005.
 */

/*
 * Ok, here's how it goes.  The UDF specs are pretty clear on how each data
 * structure is made up, but not very clear on how they relate to each other.
 * Here is the skinny... This demonstrates a filesystem with one file in the
 * root directory.  Subdirectories are treated just as normal files, but they
 * have File Id Descriptors of their children as their file data.  As for the
 * Anchor Volume Descriptor Pointer, it can exist in two of the following three
 * places: sector 256, sector n (the max sector of the disk), or sector
 * n - 256.  It's a pretty good bet that one will exist at sector 256 though.
 * One caveat is unclosed CD media.  For that, sector 256 cannot be written,
 * so the Anchor Volume Descriptor Pointer can exist at sector 512 until the
 * media is closed.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/uio.h>
#include <sys/buf.h>
#include <sys/dirent.h>
#include <sys/fcntl.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/pool.h>
#include <sys/proc.h>
#include <sys/lock.h>
#include <sys/queue.h>
#include <sys/vnode.h>
#include <sys/endian.h>
#include <sys/specdev.h>

#include <crypto/siphash.h>

#include <isofs/udf/ecma167-udf.h>
#include <isofs/udf/udf.h>
#include <isofs/udf/udf_extern.h>

struct pool udf_trans_pool;
struct pool unode_pool;
struct pool udf_ds_pool;

int udf_find_partmaps(struct umount *, struct logvol_desc *);
int udf_get_vpartmap(struct umount *, struct part_map_virt *);
int udf_get_spartmap(struct umount *, struct part_map_spare *);
int udf_get_mpartmap(struct umount *, struct part_map_meta *);
int udf_mountfs(struct vnode *, struct mount *, uint32_t, struct proc *);

const struct vfsops udf_vfsops = {
        .vfs_mount      = udf_mount,
        .vfs_start      = udf_start,
        .vfs_unmount    = udf_unmount,
        .vfs_root       = udf_root,
        .vfs_quotactl   = udf_quotactl,
        .vfs_statfs     = udf_statfs,
        .vfs_sync       = udf_sync,
        .vfs_vget       = udf_vget,
        .vfs_fhtovp     = udf_fhtovp,
        .vfs_vptofh     = udf_vptofh,
        .vfs_init       = udf_init,
        .vfs_checkexp   = udf_checkexp,
};

int
udf_init(struct vfsconf *foo)
{
        pool_init(&udf_trans_pool, MAXNAMLEN * sizeof(unicode_t), 0, IPL_NONE,
            PR_WAITOK, "udftrpl", NULL);
        pool_init(&unode_pool, sizeof(struct unode), 0, IPL_NONE,
            PR_WAITOK, "udfndpl", NULL);
        pool_init(&udf_ds_pool, sizeof(struct udf_dirstream), 0, IPL_NONE,
            PR_WAITOK, "udfdspl", NULL);

        return (0);
}

int
udf_start(struct mount *mp, int flags, struct proc *p)
{
        return (0);
}

int
udf_mount(struct mount *mp, const char *path, void *data,
    struct nameidata *ndp,  struct proc *p)
{
        struct vnode *devvp;    /* vnode of the mount device */
        struct udf_args *args = data;
        char fspec[MNAMELEN];
        int error;

        if ((mp->mnt_flag & MNT_RDONLY) == 0) {
                mp->mnt_flag |= MNT_RDONLY;
#ifdef UDF_DEBUG
                printf("udf_mount: enforcing read-only mode\n");
#endif
        }

        /*
         * No root filesystem support.  Probably not a big deal, since the
         * bootloader doesn't understand UDF.
         */
        if (mp->mnt_flag & MNT_ROOTFS)
                return (EOPNOTSUPP);

        /*
         * 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) {
                return (0);
        }

        error = copyinstr(args->fspec, fspec, sizeof(fspec), NULL);
        if (error)
                return (error);

        NDINIT(ndp, LOOKUP, FOLLOW, UIO_SYSSPACE, fspec, p);
        if ((error = namei(ndp)))
                return (error);

        devvp = ndp->ni_vp;
        if (devvp->v_type != VBLK) {
                vrele(devvp);
                return (ENOTBLK);
        }

        if (major(devvp->v_rdev) >= nblkdev) {
                vrele(devvp);
                return (ENXIO);
        }

        if ((error = udf_mountfs(devvp, mp, args->lastblock, p))) {
                vrele(devvp);
                return (error);
        }

        /*
         * Keep a copy of the mount information.
         */
        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, fspec, MNAMELEN);
        bzero(mp->mnt_stat.f_mntfromspec, MNAMELEN);
        strlcpy(mp->mnt_stat.f_mntfromspec, fspec, MNAMELEN);

        return (0);
};

/*
 * Check the descriptor tag for both the correct id and correct checksum.
 * Return zero if all is good, EINVAL if not.
 */
int
udf_checktag(struct desc_tag *tag, uint16_t id)
{
        uint8_t *itag;
        uint8_t i, cksum = 0;

        itag = (uint8_t *)tag;

        if (letoh16(tag->id) != id)
                return (EINVAL);

        for (i = 0; i < 15; i++)
                cksum = cksum + itag[i];
        cksum = cksum - itag[4];

        if (cksum == tag->cksum)
                return (0);

        return (EINVAL);
}

int
udf_mountfs(struct vnode *devvp, struct mount *mp, uint32_t lb, struct proc *p)
{
        struct buf *bp = NULL;
        struct anchor_vdp avdp;
        struct umount *ump = NULL;
        struct part_desc *pd;
        struct logvol_desc *lvd;
        struct fileset_desc *fsd;
        struct extfile_entry *xfentry;
        struct file_entry *fentry;
        uint32_t sector, size, mvds_start, mvds_end;
        uint32_t fsd_offset = 0;
        uint16_t part_num = 0, fsd_part = 0;
        int error = EINVAL;
        int logvol_found = 0, part_found = 0, fsd_found = 0;
        int bsize;

        /*
         * 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)))
                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);

        error = VOP_OPEN(devvp, FREAD, FSCRED, p);
        if (error)
                return (error);

        ump = malloc(sizeof(*ump), M_UDFMOUNT, M_WAITOK | M_ZERO);

        mp->mnt_data = ump;
        mp->mnt_stat.f_fsid.val[0] = devvp->v_rdev;
        mp->mnt_stat.f_fsid.val[1] = mp->mnt_vfc->vfc_typenum;
        mp->mnt_stat.f_namemax = NAME_MAX;
        mp->mnt_flag |= MNT_LOCAL;

        ump->um_mountp = mp;
        ump->um_dev = devvp->v_rdev;
        ump->um_devvp = devvp;

        bsize = 2048;   /* Should probe the media for its size. */

        /* 
         * Get the Anchor Volume Descriptor Pointer from sector 256.
         * Should also check sector n - 256, n, and 512.
         */
        sector = 256;
        if ((error = bread(devvp, sector * btodb(bsize), bsize, &bp)) != 0)
                goto bail;
        if ((error = udf_checktag((struct desc_tag *)bp->b_data, TAGID_ANCHOR)))
                goto bail;

        bcopy(bp->b_data, &avdp, sizeof(struct anchor_vdp));
        brelse(bp);
        bp = NULL;

        /*
         * Extract the Partition Descriptor and Logical Volume Descriptor
         * from the Volume Descriptor Sequence.
         * Should we care about the partition type right now?
         * What about multiple partitions?
         */
        mvds_start = letoh32(avdp.main_vds_ex.loc);
        mvds_end = mvds_start + (letoh32(avdp.main_vds_ex.len) - 1) / bsize;
        for (sector = mvds_start; sector < mvds_end; sector++) {
                if ((error = bread(devvp, sector * btodb(bsize), bsize, 
                                   &bp)) != 0) {
                        printf("Can't read sector %d of VDS\n", sector);
                        goto bail;
                }
                lvd = (struct logvol_desc *)bp->b_data;
                if (!udf_checktag(&lvd->tag, TAGID_LOGVOL)) {
                        ump->um_bsize = letoh32(lvd->lb_size);
                        ump->um_bmask = ump->um_bsize - 1;
                        ump->um_bshift = ffs(ump->um_bsize) - 1;
                        fsd_part = letoh16(lvd->_lvd_use.fsd_loc.loc.part_num);
                        fsd_offset = letoh32(lvd->_lvd_use.fsd_loc.loc.lb_num);
                        if (udf_find_partmaps(ump, lvd))
                                break;
                        logvol_found = 1;
                }
                pd = (struct part_desc *)bp->b_data;
                if (!udf_checktag(&pd->tag, TAGID_PARTITION)) {
                        part_found = 1;
                        part_num = letoh16(pd->part_num);
                        ump->um_len = ump->um_reallen = letoh32(pd->part_len);
                        ump->um_start = ump->um_realstart = letoh32(pd->start_loc);
                }

                brelse(bp); 
                bp = NULL;
                if ((part_found) && (logvol_found))
                        break;
        }

        if (!part_found || !logvol_found) {
                error = EINVAL;
                goto bail;
        }

        if (ISSET(ump->um_flags, UDF_MNT_USES_META)) {
                /* Read Metadata File 'File Entry' to find Metadata file. */
                struct long_ad *la;
                sector = ump->um_start + ump->um_meta_start; /* Set in udf_get_mpartmap() */
                if ((error = RDSECTOR(devvp, sector, ump->um_bsize, &bp)) != 0) {
                        printf("Cannot read sector %d for Metadata File Entry\n", sector);
                        error = EINVAL;
                        goto bail;
                }
                xfentry = (struct extfile_entry *)bp->b_data;
                fentry = (struct file_entry *)bp->b_data;
                if (udf_checktag(&xfentry->tag, TAGID_EXTFENTRY) == 0)
                        la = (struct long_ad *)&xfentry->data[letoh32(xfentry->l_ea)];
                else if (udf_checktag(&fentry->tag, TAGID_FENTRY) == 0)
                        la = (struct long_ad *)&fentry->data[letoh32(fentry->l_ea)];
                else {
                        printf("Invalid Metadata File FE @ sector %d! (tag.id %d)\n",
                            sector, fentry->tag.id);
                        error = EINVAL;
                        goto bail;
                }
                ump->um_meta_start = letoh32(la->loc.lb_num);
                ump->um_meta_len = letoh32(la->len);
                if (bp != NULL) {
                        brelse(bp);
                        bp = NULL;
                }
        } else if (fsd_part != part_num) {
                printf("FSD does not lie within the partition!\n");
                error = EINVAL;
                goto bail;
        }

        mtx_init(&ump->um_hashmtx, IPL_NONE);
        ump->um_hashtbl = hashinit(UDF_HASHTBLSIZE, M_UDFMOUNT, M_WAITOK,
            &ump->um_hashsz);
        arc4random_buf(&ump->um_hashkey, sizeof(ump->um_hashkey));

        /* Get the VAT, if needed */
        if (ump->um_flags & UDF_MNT_FIND_VAT) {
                error = udf_vat_get(ump, lb);
                if (error)
                        goto bail;
        }

        /*
         * Grab the Fileset Descriptor
         * Thanks to Chuck McCrobie <mccrobie@cablespeed.com> for pointing
         * me in the right direction here.
         */

        if (ISSET(ump->um_flags, UDF_MNT_USES_META))
                sector = ump->um_meta_start; 
        else
                sector = fsd_offset;
        udf_vat_map(ump, &sector);
        if ((error = RDSECTOR(devvp, sector, ump->um_bsize, &bp)) != 0) {
                printf("Cannot read sector %d of FSD\n", sector);
                goto bail;
        }
        fsd = (struct fileset_desc *)bp->b_data;
        if (!udf_checktag(&fsd->tag, TAGID_FSD)) {
                fsd_found = 1;
                bcopy(&fsd->rootdir_icb, &ump->um_root_icb,
                    sizeof(struct long_ad));
                if (ISSET(ump->um_flags, UDF_MNT_USES_META)) {
                        ump->um_root_icb.loc.lb_num += ump->um_meta_start; 
                        ump->um_root_icb.loc.part_num = part_num;
                }
        }

        brelse(bp);
        bp = NULL;

        if (!fsd_found) {
                printf("Couldn't find the fsd\n");
                error = EINVAL;
                goto bail;
        }

        /*
         * Find the file entry for the root directory.
         */
        sector = letoh32(ump->um_root_icb.loc.lb_num);
        size = letoh32(ump->um_root_icb.len);
        udf_vat_map(ump, &sector);
        if ((error = udf_readlblks(ump, sector, size, &bp)) != 0) {
                printf("Cannot read sector %d\n", sector);
                goto bail;
        }

        xfentry = (struct extfile_entry *)bp->b_data;
        fentry = (struct file_entry *)bp->b_data;
        error = udf_checktag(&xfentry->tag, TAGID_EXTFENTRY);
        if (error) {
                error = udf_checktag(&fentry->tag, TAGID_FENTRY);
                if (error) {
                        printf("Invalid root file entry!\n");
                        goto bail;
                }
        }

        brelse(bp);
        bp = NULL;

        devvp->v_specmountpoint = mp;

        return (0);

bail:
        if (ump != NULL) {
                hashfree(ump->um_hashtbl, UDF_HASHTBLSIZE, M_UDFMOUNT);
                free(ump, M_UDFMOUNT, 0);
                mp->mnt_data = NULL;
                mp->mnt_flag &= ~MNT_LOCAL;
        }
        if (devvp->v_specinfo)
                devvp->v_specmountpoint = NULL;
        if (bp != NULL)
                brelse(bp);

        vn_lock(devvp, LK_EXCLUSIVE|LK_RETRY);
        VOP_CLOSE(devvp, FREAD, FSCRED, p);
        VOP_UNLOCK(devvp);

        return (error);
}

int
udf_unmount(struct mount *mp, int mntflags, struct proc *p)
{
        struct umount *ump;
        struct vnode *devvp;
        int error, flags = 0;

        ump = VFSTOUDFFS(mp);
        devvp = ump->um_devvp;

        if (mntflags & MNT_FORCE)
                flags |= FORCECLOSE;

        if ((error = vflush(mp, NULL, flags)))
                return (error);

        vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
        vinvalbuf(devvp, V_SAVE, NOCRED, p, 0, INFSLP);
        (void)VOP_CLOSE(devvp, FREAD, NOCRED, p);
        VOP_UNLOCK(devvp);

        devvp->v_specmountpoint = NULL;
        vrele(devvp);

        if (ump->um_flags & UDF_MNT_USES_VAT)
                free(ump->um_vat, M_UDFMOUNT, 0);

        if (ump->um_stbl != NULL)
                free(ump->um_stbl, M_UDFMOUNT, 0);

        hashfree(ump->um_hashtbl, UDF_HASHTBLSIZE, M_UDFMOUNT);
        free(ump, M_UDFMOUNT, 0);

        mp->mnt_data = NULL;
        mp->mnt_flag &= ~MNT_LOCAL;

        return (0);
}

int
udf_root(struct mount *mp, struct vnode **vpp)
{
        struct umount *ump;
        struct vnode *vp;
        udfino_t id;
        int error;

        ump = VFSTOUDFFS(mp);

        id = udf_getid(&ump->um_root_icb);

        error = udf_vget(mp, id, vpp);
        if (error)
                return (error);

        vp = *vpp;
        vp->v_flag |= VROOT;

        return (0);
}

int
udf_quotactl(struct mount *mp, int cmds, uid_t uid, caddr_t arg,
    struct proc *p)
{
        return (EOPNOTSUPP);
}

int
udf_statfs(struct mount *mp, struct statfs *sbp, struct proc *p)
{
        struct umount *ump;

        ump = VFSTOUDFFS(mp);

        sbp->f_bsize = ump->um_bsize;
        sbp->f_iosize = ump->um_bsize;
        sbp->f_blocks = ump->um_len;
        sbp->f_bfree = 0;
        sbp->f_bavail = 0;
        sbp->f_files = 0;
        sbp->f_ffree = 0;
        sbp->f_favail = 0;
        copy_statfs_info(sbp, mp);

        return (0);
}

int
udf_sync(struct mount *mp, int waitfor, int stall, struct ucred *cred, struct proc *p)
{
        return (0);
}

int
udf_vget(struct mount *mp, ino_t ino, struct vnode **vpp)
{
        struct buf *bp;
        struct vnode *devvp;
        struct umount *ump;
        struct proc *p;
        struct vnode *vp, *nvp;
        struct unode *up;
        struct extfile_entry *xfe;
        struct file_entry *fe;
        uint32_t sector;
        int error, size;

        if (ino > (udfino_t)-1)
                panic("udf_vget: alien ino_t %llu", (unsigned long long)ino);

        p = curproc;
        bp = NULL;
        *vpp = NULL;
        ump = VFSTOUDFFS(mp);

        /* See if we already have this in the cache */
        if ((error = udf_hashlookup(ump, ino, LK_EXCLUSIVE, vpp)) != 0)
                return (error);
        if (*vpp != NULL)
                return (0);

        /*
         * Allocate memory and check the tag id's before grabbing a new
         * vnode, since it's hard to roll back if there is a problem.
         */
        up = pool_get(&unode_pool, PR_WAITOK | PR_ZERO);

        /*
         * Copy in the file entry.  Per the spec, the size can only be 1 block.
         */
        sector = ino;
        devvp = ump->um_devvp;
        udf_vat_map(ump, &sector);
        if ((error = RDSECTOR(devvp, sector, ump->um_bsize, &bp)) != 0) {
                printf("Cannot read sector %d\n", sector);
                pool_put(&unode_pool, up);
                if (bp != NULL)
                        brelse(bp);
                return (error);
        }

        xfe = (struct extfile_entry *)bp->b_data;
        fe = (struct file_entry *)bp->b_data;
        error = udf_checktag(&xfe->tag, TAGID_EXTFENTRY);
        if (error == 0) {
                size = letoh32(xfe->l_ea) + letoh32(xfe->l_ad);
        } else {
                error = udf_checktag(&fe->tag, TAGID_FENTRY);
                if (error) {
                        printf("Invalid file entry!\n");
                        pool_put(&unode_pool, up);
                        if (bp != NULL)
                                brelse(bp);
                        return (ENOMEM);
                } else
                        size = letoh32(fe->l_ea) + letoh32(fe->l_ad);
        }

        /* Allocate max size of FE/XFE. */
        up->u_fentry = malloc(size + UDF_EXTFENTRY_SIZE, M_UDFFENTRY, M_NOWAIT | M_ZERO);
        if (up->u_fentry == NULL) {
                pool_put(&unode_pool, up);
                if (bp != NULL)
                        brelse(bp);
                return (ENOMEM); /* Cannot allocate file entry block */
        }

        if (udf_checktag(&xfe->tag, TAGID_EXTFENTRY) == 0)
                bcopy(bp->b_data, up->u_fentry, size + UDF_EXTFENTRY_SIZE);
        else
                bcopy(bp->b_data, up->u_fentry, size + UDF_FENTRY_SIZE);
        
        brelse(bp);
        bp = NULL;

        if ((error = udf_allocv(mp, &vp, p))) {
                free(up->u_fentry, M_UDFFENTRY, 0);
                pool_put(&unode_pool, up);
                return (error); /* Error from udf_allocv() */
        }

        up->u_vnode = vp;
        up->u_ino = ino;
        up->u_devvp = ump->um_devvp;
        up->u_dev = ump->um_dev;
        up->u_ump = ump;
        vp->v_data = up;
        vref(ump->um_devvp);

        rrw_init_flags(&up->u_lock, "unode", RWL_DUPOK | RWL_IS_VNODE);

        /*
         * udf_hashins() will lock the vnode for us.
         */
        udf_hashins(up);

        switch (up->u_fentry->icbtag.file_type) {
        default:
                printf("Unrecognized file type (%d)\n", vp->v_type);
                vp->v_type = VREG;
                break;
        case UDF_ICB_FILETYPE_DIRECTORY:
                vp->v_type = VDIR;
                break;
        case UDF_ICB_FILETYPE_BLOCKDEVICE:
                vp->v_type = VBLK;
                break;
        case UDF_ICB_FILETYPE_CHARDEVICE:
                vp->v_type = VCHR;
                break;
        case UDF_ICB_FILETYPE_FIFO:
                vp->v_type = VFIFO;
                break;
        case UDF_ICB_FILETYPE_SOCKET:
                vp->v_type = VSOCK;
                break;
        case UDF_ICB_FILETYPE_SYMLINK:
                vp->v_type = VLNK;
                break;
        case UDF_ICB_FILETYPE_RANDOMACCESS:
        case UDF_ICB_FILETYPE_REALTIME:
        case UDF_ICB_FILETYPE_UNKNOWN:
                vp->v_type = VREG;
                break;
        }

        /* check if this is a vnode alias */
        if ((nvp = checkalias(vp, up->u_dev, ump->um_mountp)) != NULL) {
                printf("found a vnode alias\n");
                /*
                 * Discard unneeded vnode, but save its udf_node.
                 * Note that the lock is carried over in the udf_node
                 */
                nvp->v_data = vp->v_data;
                vp->v_data = NULL;
                vp->v_op = &spec_vops;
                vrele(vp);
                vgone(vp);
                /*
                 * Reinitialize aliased inode.
                 */
                vp = nvp;
                ump->um_devvp = vp;
        }

        *vpp = vp;

        return (0);
}

struct ifid {
        u_short ifid_len;
        u_short ifid_pad;
        int     ifid_ino;
        long    ifid_start;
};

int
udf_fhtovp(struct mount *mp, struct fid *fhp, struct vnode **vpp)
{
        struct ifid *ifhp;
        struct vnode *nvp;
        int error;

        ifhp = (struct ifid *)fhp;

        if ((error = VFS_VGET(mp, ifhp->ifid_ino, &nvp)) != 0) {
                *vpp = NULL;
                return (error);
        }

        *vpp = nvp;

        return (0);
}

int
udf_vptofh(struct vnode *vp, struct fid *fhp)
{
        struct unode *up;
        struct ifid *ifhp;

        up = VTOU(vp);
        ifhp = (struct ifid *)fhp;
        ifhp->ifid_len = sizeof(struct ifid);
        ifhp->ifid_ino = up->u_ino;

        return (0);
}

int
udf_checkexp(struct mount *mp, struct mbuf *nam, int *exflagsp,
    struct ucred **credanonp)
{
        return (EACCES); /* For the time being */
}

/* Handle a virtual partition map */
int
udf_get_vpartmap(struct umount *ump, struct part_map_virt *pmv)
{
        ump->um_flags |= UDF_MNT_FIND_VAT; /* Should do more than this */
        return (0);
}

/* Handle a sparable partition map */
int
udf_get_spartmap(struct umount *ump, struct part_map_spare *pms)
{
        struct buf *bp;
        int i, error;

        ump->um_stbl = malloc(letoh32(pms->st_size), M_UDFMOUNT, M_NOWAIT);
        if (ump->um_stbl == NULL)
                return (ENOMEM);

        bzero(ump->um_stbl, letoh32(pms->st_size));

        /* Calculate the number of sectors per packet */
        ump->um_psecs = letoh16(pms->packet_len) / ump->um_bsize;

        error = udf_readlblks(ump, letoh32(pms->st_loc[0]),
            letoh32(pms->st_size), &bp);

        if (error) {
                if (bp != NULL)
                        brelse(bp);
                free(ump->um_stbl, M_UDFMOUNT, 0);
                return (error); /* Failed to read sparing table */
        }

        bcopy(bp->b_data, ump->um_stbl, letoh32(pms->st_size));
        brelse(bp);
        bp = NULL;

        if (udf_checktag(&ump->um_stbl->tag, 0)) {
                free(ump->um_stbl, M_UDFMOUNT, 0);
                return (EINVAL); /* Invalid sparing table found */
        }

        /*
         * See how many valid entries there are here. The list is
         * supposed to be sorted, 0xfffffff0 and higher are not valid.
         */
        for (i = 0; i < letoh16(ump->um_stbl->rt_l); i++) {
                ump->um_stbl_len = i;
                if (letoh32(ump->um_stbl->entries[i].org) >= 0xfffffff0)
                        break;
        }

        return (0);
}

/* Handle a metadata partition map */
int
udf_get_mpartmap(struct umount *ump, struct part_map_meta *pmm)
{
        ump->um_flags |= UDF_MNT_USES_META;
        ump->um_meta_start = pmm->meta_file_lbn;
        return (0);
}

/* Scan the partition maps */
int
udf_find_partmaps(struct umount *ump, struct logvol_desc *lvd)
{
        struct regid *pmap_id;
        unsigned char regid_id[UDF_REGID_ID_SIZE + 1];
        int i, ptype, psize, error;
        uint8_t *pmap = (uint8_t *) &lvd->maps[0];

        for (i = 0; i < letoh32(lvd->n_pm); i++) {
                ptype = pmap[0];
                psize = pmap[1];

                if (ptype != 1 && ptype != 2)
                        return (EINVAL); /* Invalid partition map type */

                if (psize != sizeof(struct part_map_1)  &&
                    psize != sizeof(struct part_map_2))
                        return (EINVAL); /* Invalid partition map size */

                if (ptype == 1) {
                        pmap += sizeof(struct part_map_1);
                        continue;
                }

                /* Type 2 map. Find out the details */
                pmap_id = (struct regid *) &pmap[4];
                regid_id[UDF_REGID_ID_SIZE] = '\0';
                bcopy(&pmap_id->id[0], &regid_id[0], UDF_REGID_ID_SIZE);

                if (!bcmp(&regid_id[0], "*UDF Virtual Partition",
                    UDF_REGID_ID_SIZE))
                        error = udf_get_vpartmap(ump,
                            (struct part_map_virt *) pmap);
                else if (!bcmp(&regid_id[0], "*UDF Sparable Partition",
                    UDF_REGID_ID_SIZE))
                        error = udf_get_spartmap(ump,
                            (struct part_map_spare *) pmap);
                else if (!bcmp(&regid_id[0], "*UDF Metadata Partition",
                    UDF_REGID_ID_SIZE))
                        error = udf_get_mpartmap(ump,
                            (struct part_map_meta *) pmap);
                else
                        return (EINVAL); /* Unsupported partition map */

                if (error)
                        return (error); /* Error getting partition */

                pmap += sizeof(struct part_map_2);
        }

        return (0);
}