usr/src/sys/ufs/ffs/ffs_vfsops.c

/*
 * Copyright (c) 1989, 1991, 1993
 *      The Regents of the University of California.  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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 *
 *      @(#)ffs_vfsops.c        8.1 (Berkeley) 6/11/93
 */

#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/socket.h>
#include <sys/mount.h>
#include <sys/buf.h>
#include <sys/mbuf.h>
#include <sys/file.h>
#include <sys/disklabel.h>
#include <sys/ioctl.h>
#include <sys/errno.h>
#include <sys/malloc.h>

#include <miscfs/specfs/specdev.h>

#include <ufs/ufs/quota.h>
#include <ufs/ufs/ufsmount.h>
#include <ufs/ufs/inode.h>
#include <ufs/ufs/ufs_extern.h>

#include <ufs/ffs/fs.h>
#include <ufs/ffs/ffs_extern.h>

int ffs_sbupdate __P((struct ufsmount *, int));

struct vfsops ufs_vfsops = {
        ffs_mount,
        ufs_start,
        ffs_unmount,
        ffs_root,
        ufs_quotactl,
        ffs_statfs,
        ffs_sync,
        ffs_vget,
        ffs_fhtovp,
        ffs_vptofh,
        ffs_init,
};

extern u_long nextgennumber;

/*
 * Called by main() when ufs is going to be mounted as root.
 *
 * Name is updated by mount(8) after booting.
 */
#define ROOTNAME        "root_device"

ffs_mountroot()
{
        extern struct vnode *rootvp;
        register struct fs *fs;
        register struct mount *mp;
        struct proc *p = curproc;       /* XXX */
        struct ufsmount *ump;
        u_int size;
        int error;

        /*
         * Get vnodes for swapdev and rootdev.
         */
        if (bdevvp(swapdev, &swapdev_vp) || bdevvp(rootdev, &rootvp))
                panic("ffs_mountroot: can't setup bdevvp's");

        mp = malloc((u_long)sizeof(struct mount), M_MOUNT, M_WAITOK);
        bzero((char *)mp, (u_long)sizeof(struct mount));
        mp->mnt_op = &ufs_vfsops;
        mp->mnt_flag = MNT_RDONLY;
        if (error = ffs_mountfs(rootvp, mp, p)) {
                free(mp, M_MOUNT);
                return (error);
        }
        if (error = vfs_lock(mp)) {
                (void)ffs_unmount(mp, 0, p);
                free(mp, M_MOUNT);
                return (error);
        }
        rootfs = mp;
        mp->mnt_next = mp;
        mp->mnt_prev = mp;
        mp->mnt_vnodecovered = NULLVP;
        ump = VFSTOUFS(mp);
        fs = ump->um_fs;
        bzero(fs->fs_fsmnt, sizeof(fs->fs_fsmnt));
        fs->fs_fsmnt[0] = '/';
        bcopy((caddr_t)fs->fs_fsmnt, (caddr_t)mp->mnt_stat.f_mntonname,
            MNAMELEN);
        (void) copystr(ROOTNAME, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
            &size);
        bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
        (void)ffs_statfs(mp, &mp->mnt_stat, p);
        vfs_unlock(mp);
        inittodr(fs->fs_time);
        return (0);
}

/*
 * VFS Operations.
 *
 * mount system call
 */
int
ffs_mount(mp, path, data, ndp, p)
        register struct mount *mp;
        char *path;
        caddr_t data;
        struct nameidata *ndp;
        struct proc *p;
{
        struct vnode *devvp;
        struct ufs_args args;
        struct ufsmount *ump;
        register struct fs *fs;
        u_int size;
        int error, flags;

        if (error = copyin(data, (caddr_t)&args, sizeof (struct ufs_args)))
                return (error);
        /*
         * 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) {
                ump = VFSTOUFS(mp);
                fs = ump->um_fs;
                error = 0;
                if (fs->fs_ronly == 0 && (mp->mnt_flag & MNT_RDONLY)) {
                        flags = WRITECLOSE;
                        if (mp->mnt_flag & MNT_FORCE)
                                flags |= FORCECLOSE;
                        if (vfs_busy(mp))
                                return (EBUSY);
                        error = ffs_flushfiles(mp, flags, p);
                        vfs_unbusy(mp);
                }
                if (!error && (mp->mnt_flag & MNT_RELOAD))
                        error = ffs_reload(mp, ndp->ni_cnd.cn_cred, p);
                if (error)
                        return (error);
                if (fs->fs_ronly && (mp->mnt_flag & MNT_WANTRDWR))
                        fs->fs_ronly = 0;
                if (args.fspec == 0) {
                        /*
                         * Process export requests.
                         */
                        if (args.exflags & MNT_EXPORTED) {
                                if (error = ufs_hang_addrlist(mp, &args))
                                        return (error);
                                mp->mnt_flag |= MNT_EXPORTED;
                        }
                        if (args.exflags & MNT_DELEXPORT) {
                                ufs_free_addrlist(ump);
                                mp->mnt_flag &=
                                    ~(MNT_EXPORTED | MNT_DEFEXPORTED);
                        }
                        return (0);
                }
        }
        /*
         * Not an update, or updating the name: look up the name
         * and verify that it refers to a sensible block device.
         */
        NDINIT(ndp, LOOKUP, FOLLOW, UIO_USERSPACE, args.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 ((mp->mnt_flag & MNT_UPDATE) == 0)
                error = ffs_mountfs(devvp, mp, p);
        else {
                if (devvp != ump->um_devvp)
                        error = EINVAL; /* needs translation */
                else
                        vrele(devvp);
        }
        if (error) {
                vrele(devvp);
                return (error);
        }
        ump = VFSTOUFS(mp);
        fs = ump->um_fs;
        (void) copyinstr(path, fs->fs_fsmnt, sizeof(fs->fs_fsmnt) - 1, &size);
        bzero(fs->fs_fsmnt + size, sizeof(fs->fs_fsmnt) - size);
        bcopy((caddr_t)fs->fs_fsmnt, (caddr_t)mp->mnt_stat.f_mntonname,
            MNAMELEN);
        (void) copyinstr(args.fspec, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
            &size);
        bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
        (void)ffs_statfs(mp, &mp->mnt_stat, p);
        return (0);
}

/*
 * Reload all incore data for a filesystem (used after running fsck on
 * the root filesystem and finding things to fix). The filesystem must
 * be mounted read-only.
 *
 * Things to do to update the mount:
 *      1) invalidate all cached meta-data.
 *      2) re-read superblock from disk.
 *      3) re-read summary information from disk.
 *      4) invalidate all inactive vnodes.
 *      5) invalidate all cached file data.
 *      6) re-read inode data for all active vnodes.
 */
ffs_reload(mountp, cred, p)
        register struct mount *mountp;
        struct ucred *cred;
        struct proc *p;
{
        register struct vnode *vp, *nvp, *devvp;
        struct inode *ip;
        struct dinode *dp;
        struct csum *space;
        struct buf *bp;
        struct fs *fs;
        int i, blks, size, error;

        if ((mountp->mnt_flag & MNT_RDONLY) == 0)
                return (EINVAL);
        /*
         * Step 1: invalidate all cached meta-data.
         */
        devvp = VFSTOUFS(mountp)->um_devvp;
        if (vinvalbuf(devvp, 0, cred, p, 0, 0))
                panic("ffs_reload: dirty1");
        /*
         * Step 2: re-read superblock from disk.
         */
        if (error = bread(devvp, SBLOCK, SBSIZE, NOCRED, &bp))
                return (error);
        fs = bp->b_un.b_fs;
        if (fs->fs_magic != FS_MAGIC || fs->fs_bsize > MAXBSIZE ||
            fs->fs_bsize < sizeof(struct fs)) {
                brelse(bp);
                return (EIO);           /* XXX needs translation */
        }
        fs = VFSTOUFS(mountp)->um_fs;
        bcopy((caddr_t)&fs->fs_csp[0], (caddr_t)&bp->b_un.b_fs->fs_csp[0],
            sizeof(fs->fs_csp));
        bcopy((caddr_t)bp->b_un.b_addr, (caddr_t)fs, (u_int)fs->fs_sbsize);
        if (fs->fs_sbsize < SBSIZE)
                bp->b_flags |= B_INVAL;
        brelse(bp);
        ffs_oldfscompat(fs);
        /*
         * Step 3: re-read summary information from disk.
         */
        blks = howmany(fs->fs_cssize, fs->fs_fsize);
        space = fs->fs_csp[0];
        for (i = 0; i < blks; i += fs->fs_frag) {
                size = fs->fs_bsize;
                if (i + fs->fs_frag > blks)
                        size = (blks - i) * fs->fs_fsize;
                if (error = bread(devvp, fsbtodb(fs, fs->fs_csaddr + i), size,
                    NOCRED, &bp))
                        return (error);
                bcopy((caddr_t)bp->b_un.b_addr, fs->fs_csp[fragstoblks(fs, i)],
                    (u_int)size);
                brelse(bp);
        }
loop:
        for (vp = mountp->mnt_mounth; vp; vp = nvp) {
                nvp = vp->v_mountf;
                /*
                 * Step 4: invalidate all inactive vnodes.
                 */
                if (vp->v_usecount == 0) {
                        vgone(vp);
                        continue;
                }
                /*
                 * Step 5: invalidate all cached file data.
                 */
                if (vget(vp))
                        goto loop;
                if (vinvalbuf(vp, 0, cred, p, 0, 0))
                        panic("ffs_reload: dirty2");
                /*
                 * Step 6: re-read inode data for all active vnodes.
                 */
                ip = VTOI(vp);
                if (error = bread(devvp, fsbtodb(fs, itod(fs, ip->i_number)),
                    (int)fs->fs_bsize, NOCRED, &bp)) {
                        vput(vp);
                        return (error);
                }
                dp = bp->b_un.b_dino;
                dp += itoo(fs, ip->i_number);
                ip->i_din = *dp;
                brelse(bp);
                vput(vp);
                if (vp->v_mount != mountp)
                        goto loop;
        }
        return (0);
}

/*
 * Common code for mount and mountroot
 */
int
ffs_mountfs(devvp, mp, p)
        register struct vnode *devvp;
        struct mount *mp;
        struct proc *p;
{
        register struct ufsmount *ump;
        struct buf *bp;
        register struct fs *fs;
        dev_t dev = devvp->v_rdev;
        struct partinfo dpart;
        caddr_t base, space;
        int havepart = 0, blks;
        int error, i, size;
        int ronly;
        extern struct vnode *rootvp;

        /*
         * 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 = ufs_mountedon(devvp))
                return (error);
        if (vcount(devvp) > 1 && devvp != rootvp)
                return (EBUSY);
        if (error = vinvalbuf(devvp, V_SAVE, p->p_ucred, p, 0, 0))
                return (error);

        ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
        if (error = VOP_OPEN(devvp, ronly ? FREAD : FREAD|FWRITE, FSCRED, p))
                return (error);
        if (VOP_IOCTL(devvp, DIOCGPART, (caddr_t)&dpart, FREAD, NOCRED, p) != 0)
                size = DEV_BSIZE;
        else {
                havepart = 1;
                size = dpart.disklab->d_secsize;
        }

        bp = NULL;
        ump = NULL;
        if (error = bread(devvp, SBLOCK, SBSIZE, NOCRED, &bp))
                goto out;
        fs = bp->b_un.b_fs;
        if (fs->fs_magic != FS_MAGIC || fs->fs_bsize > MAXBSIZE ||
            fs->fs_bsize < sizeof(struct fs)) {
                error = EINVAL;         /* XXX needs translation */
                goto out;
        }
        ump = malloc(sizeof *ump, M_UFSMNT, M_WAITOK);
        bzero((caddr_t)ump, sizeof *ump);
        ump->um_fs = malloc((u_long)fs->fs_sbsize, M_UFSMNT,
            M_WAITOK);
        bcopy((caddr_t)bp->b_un.b_addr, (caddr_t)ump->um_fs,
           (u_int)fs->fs_sbsize);
        if (fs->fs_sbsize < SBSIZE)
                bp->b_flags |= B_INVAL;
        brelse(bp);
        bp = NULL;
        fs = ump->um_fs;
        fs->fs_ronly = ronly;
        if (ronly == 0)
                fs->fs_fmod = 1;
        if (havepart) {
                dpart.part->p_fstype = FS_BSDFFS;
                dpart.part->p_fsize = fs->fs_fsize;
                dpart.part->p_frag = fs->fs_frag;
                dpart.part->p_cpg = fs->fs_cpg;
        }
        blks = howmany(fs->fs_cssize, fs->fs_fsize);
        base = space = malloc((u_long)fs->fs_cssize, M_UFSMNT,
            M_WAITOK);
        for (i = 0; i < blks; i += fs->fs_frag) {
                size = fs->fs_bsize;
                if (i + fs->fs_frag > blks)
                        size = (blks - i) * fs->fs_fsize;
                error = bread(devvp, fsbtodb(fs, fs->fs_csaddr + i), size,
                        NOCRED, &bp);
                if (error) {
                        free(base, M_UFSMNT);
                        goto out;
                }
                bcopy((caddr_t)bp->b_un.b_addr, space, (u_int)size);
                fs->fs_csp[fragstoblks(fs, i)] = (struct csum *)space;
                space += size;
                brelse(bp);
                bp = NULL;
        }
        mp->mnt_data = (qaddr_t)ump;
        mp->mnt_stat.f_fsid.val[0] = (long)dev;
        mp->mnt_stat.f_fsid.val[1] = MOUNT_UFS;
        mp->mnt_maxsymlinklen = fs->fs_maxsymlinklen;
        mp->mnt_flag |= MNT_LOCAL;
        ump->um_mountp = mp;
        ump->um_dev = dev;
        ump->um_devvp = devvp;
        ump->um_nindir = fs->fs_nindir;
        ump->um_bptrtodb = fs->fs_fsbtodb;
        ump->um_seqinc = fs->fs_frag;
        for (i = 0; i < MAXQUOTAS; i++)
                ump->um_quotas[i] = NULLVP;
        devvp->v_specflags |= SI_MOUNTEDON;
        ffs_oldfscompat(fs);
        return (0);
out:
        if (bp)
                brelse(bp);
        (void)VOP_CLOSE(devvp, ronly ? FREAD : FREAD|FWRITE, NOCRED, p);
        if (ump) {
                free(ump->um_fs, M_UFSMNT);
                free(ump, M_UFSMNT);
                mp->mnt_data = (qaddr_t)0;
        }
        return (error);
}

/*
 * Sanity checks for old file systems.
 *
 * XXX - goes away some day.
 */
ffs_oldfscompat(fs)
        struct fs *fs;
{
        int i;

        fs->fs_npsect = max(fs->fs_npsect, fs->fs_nsect);       /* XXX */
        fs->fs_interleave = max(fs->fs_interleave, 1);          /* XXX */
        if (fs->fs_postblformat == FS_42POSTBLFMT)              /* XXX */
                fs->fs_nrpos = 8;                               /* XXX */
        if (fs->fs_inodefmt < FS_44INODEFMT) {                  /* XXX */
                quad_t sizepb = fs->fs_bsize;                   /* XXX */
                                                                /* XXX */
                fs->fs_maxfilesize = fs->fs_bsize * NDADDR - 1; /* XXX */
                for (i = 0; i < NIADDR; i++) {                  /* XXX */
                        sizepb *= NINDIR(fs);                   /* XXX */
                        fs->fs_maxfilesize += sizepb;           /* XXX */
                }                                               /* XXX */
                fs->fs_qbmask = ~fs->fs_bmask;                  /* XXX */
                fs->fs_qfmask = ~fs->fs_fmask;                  /* XXX */
        }                                                       /* XXX */
        return (0);
}

/*
 * unmount system call
 */
int
ffs_unmount(mp, mntflags, p)
        struct mount *mp;
        int mntflags;
        struct proc *p;
{
        register struct ufsmount *ump;
        register struct fs *fs;
        int error, flags, ronly;

        flags = 0;
        if (mntflags & MNT_FORCE) {
                if (mp == rootfs)
                        return (EINVAL);
                flags |= FORCECLOSE;
        }
        if (error = ffs_flushfiles(mp, flags, p))
                return (error);
        ump = VFSTOUFS(mp);
        fs = ump->um_fs;
        ronly = !fs->fs_ronly;
        ump->um_devvp->v_specflags &= ~SI_MOUNTEDON;
        error = VOP_CLOSE(ump->um_devvp, ronly ? FREAD : FREAD|FWRITE,
                NOCRED, p);
        vrele(ump->um_devvp);
        free(fs->fs_csp[0], M_UFSMNT);
        free(fs, M_UFSMNT);
        free(ump, M_UFSMNT);
        mp->mnt_data = (qaddr_t)0;
        mp->mnt_flag &= ~MNT_LOCAL;
        return (error);
}

/*
 * Flush out all the files in a filesystem.
 */
ffs_flushfiles(mp, flags, p)
        register struct mount *mp;
        int flags;
        struct proc *p;
{
        extern int doforce;
        register struct ufsmount *ump;
        int i, error;

        if (!doforce)
                flags &= ~FORCECLOSE;
        ump = VFSTOUFS(mp);
#ifdef QUOTA
        if (mp->mnt_flag & MNT_QUOTA) {
                if (error = vflush(mp, NULLVP, SKIPSYSTEM|flags))
                        return (error);
                for (i = 0; i < MAXQUOTAS; i++) {
                        if (ump->um_quotas[i] == NULLVP)
                                continue;
                        quotaoff(p, mp, i);
                }
                /*
                 * Here we fall through to vflush again to ensure
                 * that we have gotten rid of all the system vnodes.
                 */
        }
#endif
        error = vflush(mp, NULLVP, flags);
        return (error);
}

/*
 * Return root of a filesystem
 */
int
ffs_root(mp, vpp)
        struct mount *mp;
        struct vnode **vpp;
{
        struct vnode *nvp;
        int error;

        if (error = VFS_VGET(mp, (ino_t)ROOTINO, &nvp))
                return (error);
        *vpp = nvp;
        return (0);
}

/*
 * Get file system statistics.
 */
int
ffs_statfs(mp, sbp, p)
        struct mount *mp;
        register struct statfs *sbp;
        struct proc *p;
{
        register struct ufsmount *ump;
        register struct fs *fs;

        ump = VFSTOUFS(mp);
        fs = ump->um_fs;
        if (fs->fs_magic != FS_MAGIC)
                panic("ffs_statfs");
        sbp->f_type = MOUNT_UFS;
        sbp->f_bsize = fs->fs_fsize;
        sbp->f_iosize = fs->fs_bsize;
        sbp->f_blocks = fs->fs_dsize;
        sbp->f_bfree = fs->fs_cstotal.cs_nbfree * fs->fs_frag +
                fs->fs_cstotal.cs_nffree;
        sbp->f_bavail = (fs->fs_dsize * (100 - fs->fs_minfree) / 100) -
                (fs->fs_dsize - sbp->f_bfree);
        sbp->f_files =  fs->fs_ncg * fs->fs_ipg - ROOTINO;
        sbp->f_ffree = fs->fs_cstotal.cs_nifree;
        if (sbp != &mp->mnt_stat) {
                bcopy((caddr_t)mp->mnt_stat.f_mntonname,
                        (caddr_t)&sbp->f_mntonname[0], MNAMELEN);
                bcopy((caddr_t)mp->mnt_stat.f_mntfromname,
                        (caddr_t)&sbp->f_mntfromname[0], MNAMELEN);
        }
        return (0);
}

/*
 * Go through the disk queues to initiate sandbagged IO;
 * go through the inodes to write those that have been modified;
 * initiate the writing of the super block if it has been modified.
 *
 * Note: we are always called with the filesystem marked `MPBUSY'.
 */
int
ffs_sync(mp, waitfor, cred, p)
        struct mount *mp;
        int waitfor;
        struct ucred *cred;
        struct proc *p;
{
        register struct vnode *vp;
        register struct inode *ip;
        register struct ufsmount *ump = VFSTOUFS(mp);
        register struct fs *fs;
        int error, allerror = 0;

        fs = ump->um_fs;
        /*
         * Write back modified superblock.
         * Consistency check that the superblock
         * is still in the buffer cache.
         */
        if (fs->fs_fmod != 0) {
                if (fs->fs_ronly != 0) {                /* XXX */
                        printf("fs = %s\n", fs->fs_fsmnt);
                        panic("update: rofs mod");
                }
                fs->fs_fmod = 0;
                fs->fs_time = time.tv_sec;
                allerror = ffs_sbupdate(ump, waitfor);
        }
        /*
         * Write back each (modified) inode.
         */
loop:
        for (vp = mp->mnt_mounth; vp; vp = vp->v_mountf) {
                /*
                 * If the vnode that we are about to sync is no longer
                 * associated with this mount point, start over.
                 */
                if (vp->v_mount != mp)
                        goto loop;
                if (VOP_ISLOCKED(vp))
                        continue;
                ip = VTOI(vp);
                if ((ip->i_flag & (IMOD|IACC|IUPD|ICHG)) == 0 &&
                    vp->v_dirtyblkhd.le_next == NULL)
                        continue;
                if (vget(vp))
                        goto loop;
                if (error = VOP_FSYNC(vp, cred, waitfor, p))
                        allerror = error;
                vput(vp);
        }
        /*
         * Force stale file system control information to be flushed.
         */
        if (error = VOP_FSYNC(ump->um_devvp, cred, waitfor, p))
                allerror = error;
#ifdef QUOTA
        qsync(mp);
#endif
        return (allerror);
}

/*
 * Look up a FFS dinode number to find its incore vnode.
 * If it is not in core, read it in from the specified device.
 * If it is in core, wait for the lock bit to clear, then
 * return the inode locked. Detection and handling of mount
 * points must be done by the calling routine.
 */
int
ffs_vget(mp, ino, vpp)
        struct mount *mp;
        ino_t ino;
        struct vnode **vpp;
{
        register struct fs *fs;
        register struct inode *ip;
        struct ufsmount *ump;
        struct buf *bp;
        struct dinode *dp;
        struct vnode *vp;
        union ihead *ih;
        dev_t dev;
        int i, type, error;

        ump = VFSTOUFS(mp);
        dev = ump->um_dev;
        if ((*vpp = ufs_ihashget(dev, ino)) != NULL)
                return (0);

        /* Allocate a new vnode/inode. */
        if (error = getnewvnode(VT_UFS, mp, ffs_vnodeop_p, &vp)) {
                *vpp = NULL;
                return (error);
        }
        type = ump->um_devvp->v_tag == VT_MFS ? M_MFSNODE : M_FFSNODE; /* XXX */
        MALLOC(ip, struct inode *, sizeof(struct inode), type, M_WAITOK);
        bzero((caddr_t)ip, sizeof(struct inode));
        vp->v_data = ip;
        ip->i_vnode = vp;
        ip->i_fs = fs = ump->um_fs;
        ip->i_dev = dev;
        ip->i_number = ino;
#ifdef QUOTA
        for (i = 0; i < MAXQUOTAS; i++)
                ip->i_dquot[i] = NODQUOT;
#endif
        /*
         * Put it onto its hash chain and lock it so that other requests for
         * this inode will block if they arrive while we are sleeping waiting
         * for old data structures to be purged or for the contents of the
         * disk portion of this inode to be read.
         */
        ufs_ihashins(ip);

        /* Read in the disk contents for the inode, copy into the inode. */
        if (error = bread(ump->um_devvp, fsbtodb(fs, itod(fs, ino)),
            (int)fs->fs_bsize, NOCRED, &bp)) {
                /*
                 * The inode does not contain anything useful, so it would
                 * be misleading to leave it on its hash chain. With mode
                 * still zero, it will be unlinked and returned to the free
                 * list by vput().
                 */
                vput(vp);
                brelse(bp);
                *vpp = NULL;
                return (error);
        }
        dp = bp->b_un.b_dino;
        dp += itoo(fs, ino);
        ip->i_din = *dp;
        brelse(bp);

        /*
         * Initialize the vnode from the inode, check for aliases.
         * Note that the underlying vnode may have changed.
         */
        if (error = ufs_vinit(mp, ffs_specop_p, FFS_FIFOOPS, &vp)) {
                vput(vp);
                *vpp = NULL;
                return (error);
        }
        /*
         * Finish inode initialization now that aliasing has been resolved.
         */
        ip->i_devvp = ump->um_devvp;
        VREF(ip->i_devvp);
        /*
         * Set up a generation number for this inode if it does not
         * already have one. This should only happen on old filesystems.
         */
        if (ip->i_gen == 0) {
                if (++nextgennumber < (u_long)time.tv_sec)
                        nextgennumber = time.tv_sec;
                ip->i_gen = nextgennumber;
                if ((vp->v_mount->mnt_flag & MNT_RDONLY) == 0)
                        ip->i_flag |= IMOD;
        }
        /*
         * Ensure that uid and gid are correct. This is a temporary
         * fix until fsck has been changed to do the update.
         */
        if (fs->fs_inodefmt < FS_44INODEFMT) {          /* XXX */
                ip->i_uid = ip->i_din.di_ouid;          /* XXX */
                ip->i_gid = ip->i_din.di_ogid;          /* XXX */
        }                                               /* XXX */

        *vpp = vp;
        return (0);
}

/*
 * File handle to vnode
 *
 * Have to be really careful about stale file handles:
 * - check that the inode number is valid
 * - call ffs_vget() to get the locked inode
 * - check for an unallocated inode (i_mode == 0)
 * - check that the given client host has export rights and return
 *   those rights via. exflagsp and credanonp
 */
int
ffs_fhtovp(mp, fhp, nam, vpp, exflagsp, credanonp)
        register struct mount *mp;
        struct fid *fhp;
        struct mbuf *nam;
        struct vnode **vpp;
        int *exflagsp;
        struct ucred **credanonp;
{
        register struct ufid *ufhp;
        struct fs *fs;

        ufhp = (struct ufid *)fhp;
        fs = VFSTOUFS(mp)->um_fs;
        if (ufhp->ufid_ino < ROOTINO ||
            ufhp->ufid_ino >= fs->fs_ncg * fs->fs_ipg)
                return (ESTALE);
        return (ufs_check_export(mp, ufhp, nam, vpp, exflagsp, credanonp));
}

/*
 * Vnode pointer to File handle
 */
/* ARGSUSED */
ffs_vptofh(vp, fhp)
        struct vnode *vp;
        struct fid *fhp;
{
        register struct inode *ip;
        register struct ufid *ufhp;

        ip = VTOI(vp);
        ufhp = (struct ufid *)fhp;
        ufhp->ufid_len = sizeof(struct ufid);
        ufhp->ufid_ino = ip->i_number;
        ufhp->ufid_gen = ip->i_gen;
        return (0);
}

/*
 * Write a superblock and associated information back to disk.
 */
int
ffs_sbupdate(mp, waitfor)
        struct ufsmount *mp;
        int waitfor;
{
        register struct fs *fs = mp->um_fs;
        register struct buf *bp;
        int blks;
        caddr_t space;
        int i, size, error = 0;

        bp = getblk(mp->um_devvp, SBLOCK, (int)fs->fs_sbsize, 0, 0);
        bcopy((caddr_t)fs, bp->b_un.b_addr, (u_int)fs->fs_sbsize);
        /* Restore compatibility to old file systems.              XXX */
        if (fs->fs_postblformat == FS_42POSTBLFMT)              /* XXX */
                bp->b_un.b_fs->fs_nrpos = -1;                   /* XXX */
        if (waitfor == MNT_WAIT)
                error = bwrite(bp);
        else
                bawrite(bp);
        blks = howmany(fs->fs_cssize, fs->fs_fsize);
        space = (caddr_t)fs->fs_csp[0];
        for (i = 0; i < blks; i += fs->fs_frag) {
                size = fs->fs_bsize;
                if (i + fs->fs_frag > blks)
                        size = (blks - i) * fs->fs_fsize;
                bp = getblk(mp->um_devvp, fsbtodb(fs, fs->fs_csaddr + i),
                    size, 0, 0);
                bcopy(space, bp->b_un.b_addr, (u_int)size);
                space += size;
                if (waitfor == MNT_WAIT)
                        error = bwrite(bp);
                else
                        bawrite(bp);
        }
        return (error);
}