[apple/xnu.git] / bsd / ufs / ffs / ffs_vfsops.c

/*
 * Copyright (c) 2000-2003 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this
 * file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
/*
 * Copyright (c) 1989, 1991, 1993, 1994
 *      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        8.31 (Berkeley) 5/20/95
 */

#include <rev_endian_fs.h>
#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/disk.h>
#include <sys/ioctl.h>
#include <sys/errno.h>
#include <sys/malloc.h>
#include <sys/ubc.h>
#include <sys/quota.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>
#if REV_ENDIAN_FS
#include <ufs/ufs/ufs_byte_order.h>
#include <architecture/byte_order.h>
#endif /* REV_ENDIAN_FS */

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

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

extern u_long nextgennumber;

/*
 * Called by main() when ufs is going to be mounted as root.
 */
ffs_mountroot()
{
        extern struct vnode *rootvp;
        struct fs *fs;
        struct mount *mp;
        struct proc *p = current_proc();        /* XXX */
        struct ufsmount *ump;
        u_int size;
        int error;
        
        /*
         * Get vnode for rootdev.
         */
        if (error = bdevvp(rootdev, &rootvp)) {
                printf("ffs_mountroot: can't setup bdevvp");
                return (error);
        }
        if (error = vfs_rootmountalloc("ufs", "root_device", &mp)) {
                vrele(rootvp); /* release the reference from bdevvp() */
                return (error);
        }

        /* Must set the MNT_ROOTFS flag before doing the actual mount */
        mp->mnt_flag |= MNT_ROOTFS;

        /* Set asynchronous flag by default */
        mp->mnt_flag |= MNT_ASYNC;

        if (error = ffs_mountfs(rootvp, mp, p)) {
                mp->mnt_vfc->vfc_refcount--;

                if (mp->mnt_kern_flag & MNTK_IO_XINFO)
                        FREE(mp->mnt_xinfo_ptr, M_TEMP);
                vfs_unbusy(mp, p);

                vrele(rootvp); /* release the reference from bdevvp() */
                FREE_ZONE(mp, sizeof (struct mount), M_MOUNT);
                return (error);
        }
        simple_lock(&mountlist_slock);
        CIRCLEQ_INSERT_TAIL(&mountlist, mp, mnt_list);
        simple_unlock(&mountlist_slock);
        ump = VFSTOUFS(mp);
        fs = ump->um_fs;
        (void) copystr(mp->mnt_stat.f_mntonname, fs->fs_fsmnt, MNAMELEN - 1, 0);
        (void)ffs_statfs(mp, &mp->mnt_stat, p);
        vfs_unbusy(mp, p);
        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;
        mode_t accessmode;
        int ronly;
        int reload = 0;

        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;
                if (fs->fs_ronly == 0 && (mp->mnt_flag & MNT_RDONLY)) {
                        flags = WRITECLOSE;
                        if (mp->mnt_flag & MNT_FORCE)
                                flags |= FORCECLOSE;
                        if (error = ffs_flushfiles(mp, flags, p))
                                return (error);
                        fs->fs_clean = 1;
                        fs->fs_ronly = 1;
                        if (error = ffs_sbupdate(ump, MNT_WAIT)) {
                                fs->fs_clean = 0;
                                fs->fs_ronly = 0;
                                return (error);
                        }
                }
                /* save fs_ronly to later use */
                ronly = fs->fs_ronly;
                if ((mp->mnt_flag & MNT_RELOAD) || ronly)
                        reload = 1;
                if ((reload) &&
                    (error = ffs_reload(mp, ndp->ni_cnd.cn_cred, p)))
                        return (error);
                /* replace the ronly after load */
                fs->fs_ronly = ronly;
                /* 
                * Do not update the file system if the user was in singleuser
                * and then tries to mount -uw without fscking
                */
                if (!fs->fs_clean && ronly) {
                        printf("WARNING: trying to mount a dirty file system\n");
                        if (issingleuser() && (mp->mnt_flag & MNT_ROOTFS)) {
                                printf("WARNING: R/W mount of %s denied. Filesystem is not clean - run fsck\n",fs->fs_fsmnt);
                                /* 
                                 * Reset the readonly bit as reload might have
                                 * modified this bit 
                                 */
                                fs->fs_ronly = 1;
                                return(EPERM);
                        }
                }

                if (ronly && (mp->mnt_kern_flag & MNTK_WANTRDWR)) {
                        /*
                         * If upgrade to read-write by non-root, then verify
                         * that user has necessary permissions on the device.
                         */
                        if (p->p_ucred->cr_uid != 0) {
                                devvp = ump->um_devvp;
                                vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, p);
                                if (error = VOP_ACCESS(devvp, VREAD | VWRITE,
                                    p->p_ucred, p)) {
                                        VOP_UNLOCK(devvp, 0, p);
                                        return (error);
                                }
                                VOP_UNLOCK(devvp, 0, p);
                        }
                        fs->fs_ronly = 0;
                        fs->fs_clean = 0;
                        (void) ffs_sbupdate(ump, MNT_WAIT);
                }
                if (args.fspec == 0) {
                        /*
                         * Process export requests.
                         */
                        return (vfs_export(mp, &ump->um_export, &args.export));
                }
        }
        /*
         * 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 mount by non-root, then verify that user has necessary
         * permissions on the device.
         */
        if (p->p_ucred->cr_uid != 0) {
                accessmode = VREAD;
                if ((mp->mnt_flag & MNT_RDONLY) == 0)
                        accessmode |= VWRITE;
                vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, p);
                if (error = VOP_ACCESS(devvp, accessmode, p->p_ucred, p)) {
                        vput(devvp);
                        return (error);
                }
                VOP_UNLOCK(devvp, 0, p);
        }
        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_t *)&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_t *)&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;
        void *space;
        struct buf *bp;
        struct fs *fs, *newfs;
        int i, blks, size, error;
        u_int64_t maxfilesize;                                  /* XXX */
        int32_t *lp;
#if REV_ENDIAN_FS
        int rev_endian = (mountp->mnt_flag & MNT_REVEND);
#endif /* REV_ENDIAN_FS */

        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.
         */
        VOP_DEVBLOCKSIZE(devvp,&size);

        if (error = bread(devvp, (ufs_daddr_t)(SBOFF/size), SBSIZE, NOCRED,&bp)) {
                brelse(bp);
                return (error);
        }
        newfs = (struct fs *)bp->b_data;
#if REV_ENDIAN_FS
        if (rev_endian) {
                byte_swap_sbin(newfs);
        }
#endif /* REV_ENDIAN_FS */
        if (newfs->fs_magic != FS_MAGIC || newfs->fs_bsize > MAXBSIZE ||
            newfs->fs_bsize < sizeof(struct fs)) {
#if REV_ENDIAN_FS
                if (rev_endian)
                        byte_swap_sbout(newfs);
#endif /* REV_ENDIAN_FS */

                brelse(bp);
                return (EIO);           /* XXX needs translation */
        }
        fs = VFSTOUFS(mountp)->um_fs;
        /*
         * Copy pointer fields back into superblock before copying in   XXX
         * new superblock. These should really be in the ufsmount.      XXX
         * Note that important parameters (eg fs_ncg) are unchanged.
         */
        newfs->fs_csp = fs->fs_csp;
        newfs->fs_maxcluster = fs->fs_maxcluster;
        newfs->fs_contigdirs = fs->fs_contigdirs;
        bcopy(newfs, fs, (u_int)fs->fs_sbsize);
        if (fs->fs_sbsize < SBSIZE)
                bp->b_flags |= B_INVAL;
#if REV_ENDIAN_FS
        if (rev_endian)
                byte_swap_sbout(newfs);
#endif /* REV_ENDIAN_FS */
        brelse(bp);
        mountp->mnt_maxsymlinklen = fs->fs_maxsymlinklen;
        ffs_oldfscompat(fs);
        maxfilesize = 0x100000000ULL;    /* 4GB */
        if (fs->fs_maxfilesize > maxfilesize)                   /* XXX */
                fs->fs_maxfilesize = maxfilesize;               /* XXX */
        /*
         * Step 3: re-read summary information from disk.
         */
        blks = howmany(fs->fs_cssize, fs->fs_fsize);
        space = fs->fs_csp;
        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)) {
                        brelse(bp);
                        return (error);
                }
#if REV_ENDIAN_FS
                if (rev_endian) {
                        /* csum swaps */
                        byte_swap_ints((int *)bp->b_data, size / sizeof(int));
                }
#endif /* REV_ENDIAN_FS */
                bcopy(bp->b_data, space, (u_int)size);
#if REV_ENDIAN_FS
                if (rev_endian) {
                        /* csum swaps */
                        byte_swap_ints((int *)bp->b_data, size / sizeof(int));
                }
#endif /* REV_ENDIAN_FS */
                space = (char *) space + size;
                brelse(bp);
        }
        /*
         * We no longer know anything about clusters per cylinder group.
         */
        if (fs->fs_contigsumsize > 0) {
                lp = fs->fs_maxcluster;
                for (i = 0; i < fs->fs_ncg; i++)
                        *lp++ = fs->fs_contigsumsize;
        }

loop:
        simple_lock(&mntvnode_slock);
        for (vp = mountp->mnt_vnodelist.lh_first; vp != NULL; vp = nvp) {
                if (vp->v_mount != mountp) {
                        simple_unlock(&mntvnode_slock);
                        goto loop;
                }
                nvp = vp->v_mntvnodes.le_next;
                /*
                 * Step 4: invalidate all inactive vnodes.
                 */
                if (vrecycle(vp, &mntvnode_slock, p))
                        goto loop;
                /*
                 * Step 5: invalidate all cached file data.
                 */
                simple_lock(&vp->v_interlock);
                simple_unlock(&mntvnode_slock);
                if (vget(vp, LK_EXCLUSIVE | LK_INTERLOCK, p)) {
                        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, ino_to_fsba(fs, ip->i_number)),
                    (int)fs->fs_bsize, NOCRED, &bp)) {
                        brelse(bp);
                        vput(vp);
                        return (error);
                }
#if REV_ENDIAN_FS
        if (rev_endian) {
                byte_swap_inode_in(((struct dinode *)bp->b_data +
                    ino_to_fsbo(fs, ip->i_number)), ip);
        } else {
#endif /* REV_ENDIAN_FS */
                ip->i_din = *((struct dinode *)bp->b_data +
                    ino_to_fsbo(fs, ip->i_number));
#if REV_ENDIAN_FS
        }
#endif /* REV_ENDIAN_FS */
                brelse(bp);
                vput(vp);
                simple_lock(&mntvnode_slock);
        }
        simple_unlock(&mntvnode_slock);
        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;
        struct buf *cgbp;
        struct cg *cgp;
        int32_t clustersumoff;
        void *space;
        int error, i, blks, size, ronly;
        int32_t *lp;
        struct ucred *cred;
        extern struct vnode *rootvp;
        u_int64_t maxfilesize;                                  /* XXX */
        u_int dbsize = DEV_BSIZE;
#if REV_ENDIAN_FS
        int rev_endian=0;
#endif /* REV_ENDIAN_FS */
        dev = devvp->v_rdev;
        cred = p ? p->p_ucred : NOCRED;
        /*
         * 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);
        if (error = vinvalbuf(devvp, V_SAVE, cred, 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);

        VOP_DEVBLOCKSIZE(devvp,&size);

        bp = NULL;
        ump = NULL;
        if (error = bread(devvp, (ufs_daddr_t)(SBOFF/size), SBSIZE, cred, &bp))
                goto out;
        fs = (struct fs *)bp->b_data;
#if REV_ENDIAN_FS
        if (fs->fs_magic != FS_MAGIC || fs->fs_bsize > MAXBSIZE ||
            fs->fs_bsize < sizeof(struct fs)) {
                int magic = fs->fs_magic;
                
                byte_swap_ints(&magic, 1);
                if (magic != FS_MAGIC) {
                        error = EINVAL;
                        goto out;
                }
                byte_swap_sbin(fs);
                if (fs->fs_magic != FS_MAGIC || fs->fs_bsize > MAXBSIZE ||
                        fs->fs_bsize < sizeof(struct fs)) {
                        byte_swap_sbout(fs);
                        error = EINVAL;         /* XXX needs translation */
                        goto out;
                }
                rev_endian=1;
        }
#endif /* REV_ENDIAN_FS */
        if (fs->fs_magic != FS_MAGIC || fs->fs_bsize > MAXBSIZE ||
            fs->fs_bsize < sizeof(struct fs)) {
#if REV_ENDIAN_FS
                if (rev_endian)
                        byte_swap_sbout(fs);
#endif /* REV_ENDIAN_FS */
                error = EINVAL;         /* XXX needs translation */
                goto out;
        }


        /*
         * Buffer cache does not handle multiple pages in a buf when
         * invalidating incore buffer in pageout. There are no locks 
         * in the pageout path.  So there is a danger of loosing data when
         * block allocation happens at the same time a pageout of buddy
         * page occurs. incore() returns buf with both
         * pages, this leads vnode-pageout to incorrectly flush of entire. 
         * buf. Till the low level ffs code is modified to deal with these
         * do not mount any FS more than 4K size.
         */
        /*
         * Can't mount filesystems with a fragment size less than DIRBLKSIZ
         */
        /*
         * Don't mount dirty filesystems, except for the root filesystem
         */
        if ((fs->fs_bsize > PAGE_SIZE) || (fs->fs_fsize < DIRBLKSIZ) ||
        ((!(mp->mnt_flag & MNT_ROOTFS)) && (!fs->fs_clean))) {
#if REV_ENDIAN_FS
                if (rev_endian)
                        byte_swap_sbout(fs);
#endif /* REV_ENDIAN_FS */
        error = ENOTSUP;
        goto out;
    }
         
        /* Let's figure out the devblock size the file system is with */
        /* the device block size = fragment size / number of sectors per frag */

        dbsize = fs->fs_fsize / NSPF(fs);
        if(dbsize <= 0 ) {
                kprintf("device blocksize computaion failed\n");
        } else {
                if (VOP_IOCTL(devvp, DKIOCSETBLOCKSIZE, (caddr_t)&dbsize,
                                FWRITE, NOCRED, p) != 0) {  
                        kprintf("failed to set device blocksize\n");
                }  
                /* force the specfs to reread blocksize from size() */
                set_fsblocksize(devvp);
        } 

        /* cache the IO attributes */
        error = vfs_init_io_attributes(devvp, mp);
        if (error) {
                printf("ffs_mountfs: vfs_init_io_attributes returned %d\n",
                        error);
                goto out;
        }

        /* XXX updating 4.2 FFS superblocks trashes rotational layout tables */
        if (fs->fs_postblformat == FS_42POSTBLFMT && !ronly) {
#if REV_ENDIAN_FS
                if (rev_endian)
                        byte_swap_sbout(fs);
#endif /* REV_ENDIAN_FS */
                error = EROFS;          /* needs translation */
                goto out;
        }

        /* If we are not mounting read only, then check for overlap 
         * condition in cylinder group's free block map.
         * If overlap exists, then force this into a read only mount
         * to avoid further corruption. PR#2216969
         */
        if (ronly == 0){
            if (error = bread (devvp, fsbtodb(fs, cgtod(fs, 0)),
                                                 (int)fs->fs_cgsize, NOCRED, &cgbp)) {
                        brelse(cgbp);
                        goto out;
                }
                cgp = (struct cg *)cgbp->b_data;
#if REV_ENDIAN_FS
                if (rev_endian)
                        byte_swap_cgin(cgp,fs);
#endif /* REV_ENDIAN_FS */
                if (!cg_chkmagic(cgp)){
#if REV_ENDIAN_FS
                                if (rev_endian)
                                        byte_swap_cgout(cgp,fs);
#endif /* REV_ENDIAN_FS */
                        brelse(cgbp);
                        goto out;
                }
                if (cgp->cg_clustersumoff != 0) {
                        /* Check for overlap */
                        clustersumoff = cgp->cg_freeoff +
                        howmany(fs->fs_cpg * fs->fs_spc / NSPF(fs), NBBY);
                        clustersumoff = roundup(clustersumoff, sizeof(long));
                        if (cgp->cg_clustersumoff < clustersumoff) {
                        /* Overlap exists */
                        mp->mnt_flag |= MNT_RDONLY;
                                ronly = 1;
                        }
                }
#if REV_ENDIAN_FS
                        if (rev_endian)
                                byte_swap_cgout(cgp,fs);
#endif /* REV_ENDIAN_FS */
                        brelse(cgbp);
        }

        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(bp->b_data, ump->um_fs, (u_int)fs->fs_sbsize);
        if (fs->fs_sbsize < SBSIZE)
                bp->b_flags |= B_INVAL;
#if REV_ENDIAN_FS
        if (rev_endian)
                byte_swap_sbout(fs);
#endif /* REV_ENDIAN_FS */
        brelse(bp);
        bp = NULL;
        fs = ump->um_fs;
        fs->fs_ronly = ronly;
        size = fs->fs_cssize;
        blks = howmany(size, fs->fs_fsize);
        if (fs->fs_contigsumsize > 0)
                size += fs->fs_ncg * sizeof(int32_t);
        size += fs->fs_ncg * sizeof(u_int8_t);
        space = _MALLOC((u_long)size, M_UFSMNT, M_WAITOK);
        fs->fs_csp = space;
        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,
                    cred, &bp)) {
                        _FREE(fs->fs_csp, M_UFSMNT);
                        goto out;
                }
                bcopy(bp->b_data, space, (u_int)size);
#if REV_ENDIAN_FS
                if (rev_endian)
                        byte_swap_ints((int *) space, size / sizeof(int));
#endif /* REV_ENDIAN_FS */
                space = (char *)space + size;
                brelse(bp);
                bp = NULL;
        }
        if (fs->fs_contigsumsize > 0) {
                fs->fs_maxcluster = lp = space;
                for (i = 0; i < fs->fs_ncg; i++)
                        *lp++ = fs->fs_contigsumsize;
                space = lp;
        }
        size = fs->fs_ncg * sizeof(u_int8_t);
        fs->fs_contigdirs = (u_int8_t *)space;
        space = (u_int8_t *)space + size;
        bzero(fs->fs_contigdirs, size);
        /* XXX Compatibility for old filesystems */
        if (fs->fs_avgfilesize <= 0)
                fs->fs_avgfilesize = AVFILESIZ;
        if (fs->fs_avgfpdir <= 0)
                fs->fs_avgfpdir = AFPDIR;
        /* XXX End of compatibility */
        mp->mnt_data = (qaddr_t)ump;
        mp->mnt_stat.f_fsid.val[0] = (long)dev;
        mp->mnt_stat.f_fsid.val[1] = mp->mnt_vfc->vfc_typenum;
        /* XXX warning hardcoded max symlen and not "mp->mnt_maxsymlinklen = fs->fs_maxsymlinklen;" */
        mp->mnt_maxsymlinklen = 60;
#if REV_ENDIAN_FS
        if (rev_endian)
                mp->mnt_flag |= MNT_REVEND;
#endif /* REV_ENDIAN_FS */
        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_qfiles[i].qf_vp = NULLVP;
        devvp->v_specflags |= SI_MOUNTEDON;
        ffs_oldfscompat(fs);
        ump->um_savedmaxfilesize = fs->fs_maxfilesize;          /* XXX */
        maxfilesize = 0x100000000ULL;    /* 4GB */
#if 0
        maxfilesize = (u_int64_t)0x40000000 * fs->fs_bsize - 1; /* XXX */
#endif /* 0 */
        if (fs->fs_maxfilesize > maxfilesize)                   /* XXX */
                fs->fs_maxfilesize = maxfilesize;               /* XXX */
        if (ronly == 0) {
                fs->fs_clean = 0;
                (void) ffs_sbupdate(ump, MNT_WAIT);
        }
        return (0);
out:
        if (bp)
                brelse(bp);
        (void)VOP_CLOSE(devvp, ronly ? FREAD : FREAD|FWRITE, cred, 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 */
                u_int64_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;
        int force;

        flags = 0;
        force = 0;
        if (mntflags & MNT_FORCE) {
                flags |= FORCECLOSE;
                force = 1;
        }
        if ( (error = ffs_flushfiles(mp, flags, p)) && !force )
                return (error);
        ump = VFSTOUFS(mp);
        fs = ump->um_fs;
        if (fs->fs_ronly == 0) {
                fs->fs_clean = 1;
                if (error = ffs_sbupdate(ump, MNT_WAIT)) {
                        fs->fs_clean = 0;
#ifdef notyet
                /* we can atleast cleanup ; as the media could be WP */
                /* & during mount, we do not check for write failures  */
                /* FIXME LATER : the Correct fix would be to have */
                /* mount detect the WP media and downgrade to readonly mount */
                /* For now, here it is */
                        return (error);
#endif /* notyet */
                }
        }
        ump->um_devvp->v_specflags &= ~SI_MOUNTEDON;
        error = VOP_CLOSE(ump->um_devvp, fs->fs_ronly ? FREAD : FREAD|FWRITE,
                NOCRED, p);
        if (error && !force)
                return (error);
        vrele(ump->um_devvp);

        _FREE(fs->fs_csp, M_UFSMNT);
        _FREE(fs, M_UFSMNT);
        _FREE(ump, M_UFSMNT);
        mp->mnt_data = (qaddr_t)0;
#if REV_ENDIAN_FS
        mp->mnt_flag &= ~MNT_REVEND;
#endif /* REV_ENDIAN_FS */
        return (0);
}

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

        ump = VFSTOUFS(mp);

#if QUOTA
        /*
         * NOTE: The open quota files have an indirect reference
         * on the root directory vnode.  We must account for this
         * extra reference when doing the intial vflush.
         */
        if (mp->mnt_flag & MNT_QUOTA) {
                struct vnode *rootvp = NULLVP;
                int quotafilecnt = 0;

                /* Find out how many quota files we have open. */
                for (i = 0; i < MAXQUOTAS; i++) {
                        if (ump->um_qfiles[i].qf_vp != NULLVP)
                                ++quotafilecnt;
                }

                /*
                 * Check if the root vnode is in our inode hash
                 * (so we can skip over it).
                 */
                rootvp = ufs_ihashget(ump->um_dev, ROOTINO);

                error = vflush(mp, rootvp, SKIPSYSTEM|flags);

                if (rootvp) {
                        /*
                         * See if there are additional references on the
                         * root vp besides the ones obtained from the open
                         * quota files and the hfs_chashget call above.
                         */
                        if ((error == 0) &&
                            (rootvp->v_usecount > (1 + quotafilecnt))) {
                                error = EBUSY;  /* root dir is still open */
                        }
                        vput(rootvp);
                }
                if (error && (flags & FORCECLOSE) == 0)
                        return (error);

                for (i = 0; i < MAXQUOTAS; i++) {
                        if (ump->um_qfiles[i].qf_vp == 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, SKIPSWAP|flags);
        error = vflush(mp, NULLVP, flags);
        return (error);
}

/*
 * 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_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 = freespace(fs, fs->fs_minfree);
        sbp->f_files =  fs->fs_ncg * fs->fs_ipg - ROOTINO;
        sbp->f_ffree = fs->fs_cstotal.cs_nifree;
        if (sbp != &mp->mnt_stat) {
                sbp->f_type = mp->mnt_vfc->vfc_typenum;
                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;
{
        struct vnode *nvp, *vp;
        struct inode *ip;
        struct ufsmount *ump = VFSTOUFS(mp);
        struct fs *fs;
        int error, allerror = 0;

        fs = ump->um_fs;
        if (fs->fs_fmod != 0 && fs->fs_ronly != 0) {            /* XXX */
                printf("fs = %s\n", fs->fs_fsmnt);
                panic("update: rofs mod");
        }
        /*
         * Write back each (modified) inode.
         */
        simple_lock(&mntvnode_slock);
loop:
        for (vp = mp->mnt_vnodelist.lh_first;
             vp != NULL;
             vp = nvp) {
                int didhold = 0;

                /*
                 * 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;
                simple_lock(&vp->v_interlock);
                nvp = vp->v_mntvnodes.le_next;
                ip = VTOI(vp);

                // restart our whole search if this guy is locked
                // or being reclaimed.
                if (ip == NULL || vp->v_flag & (VXLOCK|VORECLAIM)) {
                        simple_unlock(&vp->v_interlock);
                        continue;
                }

                if ((vp->v_type == VNON) ||
                    ((ip->i_flag & (IN_ACCESS | IN_CHANGE | IN_MODIFIED | IN_UPDATE)) == 0 &&
                     vp->v_dirtyblkhd.lh_first == NULL && !(vp->v_flag & VHASDIRTY))) {
                        simple_unlock(&vp->v_interlock);
                        continue;
                }
                simple_unlock(&mntvnode_slock);
                error = vget(vp, LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, p);
                if (error) {
                        simple_lock(&mntvnode_slock);
                        if (error == ENOENT)
                                goto loop;
                        continue;
                }
                didhold = ubc_hold(vp);
                if (error = VOP_FSYNC(vp, cred, waitfor, p))
                        allerror = error;
                VOP_UNLOCK(vp, 0, p);
                if (didhold)
                        ubc_rele(vp);
                vrele(vp);
                simple_lock(&mntvnode_slock);
        }
        simple_unlock(&mntvnode_slock);
        /*
         * Force stale file system control information to be flushed.
         */
        if (error = VOP_FSYNC(ump->um_devvp, cred, waitfor, p))
                allerror = error;
#if QUOTA
        qsync(mp);
#endif
        /*
         * Write back modified superblock.
         */
        if (fs->fs_fmod != 0) {
                fs->fs_fmod = 0;
                fs->fs_time = time.tv_sec;
                if (error = ffs_sbupdate(ump, waitfor))
                        allerror = error;
        }
        return (allerror);
}

/*
 * Look up a FFS dinode number to find its incore vnode, otherwise read it
 * in from disk.  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, inop, vpp)
        struct mount *mp;
        void *inop;
        struct vnode **vpp;
{
        struct proc *p = current_proc();                /* XXX */
        struct fs *fs;
        struct inode *ip;
        struct ufsmount *ump;
        struct buf *bp;
        struct vnode *vp;
        ino_t ino;
        dev_t dev;
        int i, type, error = 0;

        ino = (ino_t) inop;
        ump = VFSTOUFS(mp);
        dev = ump->um_dev;

        /* Check for unmount in progress */
        if (mp->mnt_kern_flag & MNTK_UNMOUNT) {
                *vpp = NULL;
                return (EPERM);
        }

        /* check in the inode hash */
        if ((*vpp = ufs_ihashget(dev, ino)) != NULL) {
                vp = *vpp;
                UBCINFOCHECK("ffs_vget", vp);
                return (0);
        }

        /*
         * Not in inode hash.
         * Allocate a new vnode/inode.
         */
        type = ump->um_devvp->v_tag == VT_MFS ? M_MFSNODE : M_FFSNODE; /* XXX */
        MALLOC_ZONE(ip, struct inode *, sizeof(struct inode), type, M_WAITOK);
        bzero((caddr_t)ip, sizeof(struct inode));
        lockinit(&ip->i_lock, PINOD, "inode", 0, 0);
        /* lock the inode */
        lockmgr(&ip->i_lock, LK_EXCLUSIVE, (struct slock *)0, p);

        ip->i_fs = fs = ump->um_fs;
        ip->i_dev = dev;
        ip->i_number = ino;
        SET(ip->i_flag, IN_ALLOC);
#if QUOTA
        for (i = 0; i < MAXQUOTAS; i++)
                ip->i_dquot[i] = NODQUOT;
#endif

        /*
         * We could have blocked in MALLOC_ZONE. Check for the race.
         */
        if ((*vpp = ufs_ihashget(dev, ino)) != NULL) {
                /* lost the race, clean up */
                FREE_ZONE(ip, sizeof(struct inode), type);
                vp = *vpp;
                UBCINFOCHECK("ffs_vget", vp);
                return (0);
        }

        /*
         * Put it onto its hash chain locked 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, ino_to_fsba(fs, ino)),
            (int)fs->fs_bsize, NOCRED, &bp)) {
                brelse(bp);
                goto errout;
        }
#if REV_ENDIAN_FS
        if (mp->mnt_flag & MNT_REVEND) {
                byte_swap_inode_in(((struct dinode *)bp->b_data + ino_to_fsbo(fs, ino)),ip);
        } else {
                ip->i_din = *((struct dinode *)bp->b_data + ino_to_fsbo(fs, ino));
        }
#else
        ip->i_din = *((struct dinode *)bp->b_data + ino_to_fsbo(fs, ino));
#endif /* REV_ENDIAN_FS */
        brelse(bp);

        if (error = getnewvnode(VT_UFS, mp, ffs_vnodeop_p, &vp))
                goto errout;

        vp->v_data = ip;
        ip->i_vnode = vp;

        /*
         * 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;
                goto out;
        }
        /*
         * 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 |= IN_MODIFIED;
        }
        /*
         * 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 */

        if (UBCINFOMISSING(vp) || UBCINFORECLAIMED(vp))
                ubc_info_init(vp);
        *vpp = vp;

out:
        CLR(ip->i_flag, IN_ALLOC);
        if (ISSET(ip->i_flag, IN_WALLOC))
                wakeup(ip);
        return (error);

errout:
        ufs_ihashrem(ip);
        CLR(ip->i_flag, IN_ALLOC);
        if (ISSET(ip->i_flag, IN_WALLOC))
                wakeup(ip);
        FREE_ZONE(ip, sizeof(struct inode), type);
        *vpp = NULL;
        return (error);
}

/*
 * 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);
}

/*
 * Initialize the filesystem; just use ufs_init.
 */
int
ffs_init(vfsp)
        struct vfsconf *vfsp;
{

        return (ufs_init(vfsp));
}

/*
 * fast filesystem related variables.
 */
ffs_sysctl(name, namelen, oldp, oldlenp, newp, newlen, p)
        int *name;
        u_int namelen;
        void *oldp;
        size_t *oldlenp;
        void *newp;
        size_t newlen;
        struct proc *p;
{
        extern int doclusterread, doclusterwrite, doreallocblks, doasyncfree;

        /* all sysctl names at this level are terminal */
        if (namelen != 1)
                return (ENOTDIR);               /* overloaded */

        switch (name[0]) {
        case FFS_CLUSTERREAD:
                return (sysctl_int(oldp, oldlenp, newp, newlen,
                    &doclusterread));
        case FFS_CLUSTERWRITE:
                return (sysctl_int(oldp, oldlenp, newp, newlen,
                    &doclusterwrite));
        case FFS_REALLOCBLKS:
                return (sysctl_int(oldp, oldlenp, newp, newlen,
                    &doreallocblks));
        case FFS_ASYNCFREE:
                return (sysctl_int(oldp, oldlenp, newp, newlen, &doasyncfree));
        default:
                return (EOPNOTSUPP);
        }
        /* NOTREACHED */
}

/*
 * Write a superblock and associated information back to disk.
 */
int
ffs_sbupdate(mp, waitfor)
        struct ufsmount *mp;
        int waitfor;
{
        register struct fs *dfs, *fs = mp->um_fs;
        register struct buf *bp;
        int blks;
        void *space;
        int i, size, error, allerror = 0;
        int devBlockSize=0;
#if REV_ENDIAN_FS
        int rev_endian=(mp->um_mountp->mnt_flag & MNT_REVEND);
#endif /* REV_ENDIAN_FS */

        /*
         * First write back the summary information.
         */
        blks = howmany(fs->fs_cssize, fs->fs_fsize);
        space = fs->fs_csp;
        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, BLK_META);
                bcopy(space, bp->b_data, (u_int)size);
#if REV_ENDIAN_FS
                if (rev_endian) {
                        byte_swap_ints((int *)bp->b_data, size / sizeof(int));
                }
#endif /* REV_ENDIAN_FS */
                space = (char *)space + size;
                if (waitfor != MNT_WAIT)
                        bawrite(bp);
                else if (error = bwrite(bp))
                        allerror = error;
        }
        /*
         * Now write back the superblock itself. If any errors occurred
         * up to this point, then fail so that the superblock avoids
         * being written out as clean.
         */
        if (allerror)
                return (allerror);
        VOP_DEVBLOCKSIZE(mp->um_devvp,&devBlockSize);
        bp = getblk(mp->um_devvp, (SBOFF/devBlockSize), (int)fs->fs_sbsize, 0, 0, BLK_META);
        bcopy((caddr_t)fs, bp->b_data, (u_int)fs->fs_sbsize);
        /* Restore compatibility to old file systems.              XXX */
        dfs = (struct fs *)bp->b_data;                          /* XXX */
        if (fs->fs_postblformat == FS_42POSTBLFMT)              /* XXX */
                dfs->fs_nrpos = -1;                             /* XXX */
#if REV_ENDIAN_FS
        /*  
        *  Swapping bytes here ; so that in case
        *   of inode format < FS_44INODEFMT appropriate
        *   fields get moved 
        */
        if (rev_endian) {
                byte_swap_sbout((struct fs *)bp->b_data);
        }
#endif /* REV_ENDIAN_FS */
        if (fs->fs_inodefmt < FS_44INODEFMT) {                  /* XXX */
                int32_t *lp, tmp;                               /* XXX */
                                                                /* XXX */
                lp = (int32_t *)&dfs->fs_qbmask;                /* XXX */
                tmp = lp[4];                                    /* XXX */
                for (i = 4; i > 0; i--)                         /* XXX */
                        lp[i] = lp[i-1];                        /* XXX */
                lp[0] = tmp;                                    /* XXX */
        }                                                       /* XXX */
#if REV_ENDIAN_FS
        /* Note that dfs is already swapped so swap the filesize
        *  before writing
        */
        if (rev_endian) {
                dfs->fs_maxfilesize = NXSwapLongLong(mp->um_savedmaxfilesize);          /* XXX */
        } else {
#endif /* REV_ENDIAN_FS */
                dfs->fs_maxfilesize = mp->um_savedmaxfilesize;  /* XXX */
#if REV_ENDIAN_FS
        }
#endif /* REV_ENDIAN_FS */
        if (waitfor != MNT_WAIT)
                bawrite(bp);
        else if (error = bwrite(bp))
                allerror = error;

        return (allerror);
}