usr/src/sys/nfs/nfs_vfsops.c

/*
 * Copyright (c) 1989 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Rick Macklem at The University of Guelph.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 *      @(#)nfs_vfsops.c        7.22 (Berkeley) %G%
 */

#include "param.h"
#include "signal.h"
#include "user.h"
#include "proc.h"
#include "vnode.h"
#include "mount.h"
#include "errno.h"
#include "buf.h"
#include "mbuf.h"
#include "socket.h"
#include "systm.h"
#include "nfsv2.h"
#include "nfsnode.h"
#include "nfsmount.h"
#include "nfs.h"
#include "xdr_subs.h"
#include "nfsm_subs.h"

/*
 * nfs vfs operations.
 */
int nfs_mount();
int nfs_start();
int nfs_unmount();
int nfs_root();
int nfs_quotactl();
int nfs_statfs();
int nfs_sync();
int nfs_fhtovp();
int nfs_vptofh();
int nfs_init();

struct vfsops nfs_vfsops = {
        nfs_mount,
        nfs_start,
        nfs_unmount,
        nfs_root,
        nfs_quotactl,
        nfs_statfs,
        nfs_sync,
        nfs_fhtovp,
        nfs_vptofh,
        nfs_init,
};

static u_char nfs_mntid;
extern u_long nfs_procids[NFS_NPROCS];
extern u_long nfs_prog, nfs_vers;
void nfs_disconnect();

#define TRUE    1
#define FALSE   0

/*
 * nfs statfs call
 */
nfs_statfs(mp, sbp)
        struct mount *mp;
        register struct statfs *sbp;
{
        register struct vnode *vp;
        register struct nfsv2_statfs *sfp;
        register caddr_t cp;
        register long t1;
        caddr_t bpos, dpos, cp2;
        u_long xid;
        int error = 0;
        struct mbuf *mreq, *mrep, *md, *mb, *mb2;
        struct nfsmount *nmp;
        struct ucred *cred;
        struct nfsnode *np;

        nmp = VFSTONFS(mp);
        if (error = nfs_nget(mp, &nmp->nm_fh, &np))
                return (error);
        vp = NFSTOV(np);
        nfsstats.rpccnt[NFSPROC_STATFS]++;
        cred = crget();
        cred->cr_ngroups = 1;
        nfsm_reqhead(nfs_procids[NFSPROC_STATFS], cred, NFSX_FH);
        nfsm_fhtom(vp);
        nfsm_request(vp, NFSPROC_STATFS, u.u_procp);
        nfsm_disect(sfp, struct nfsv2_statfs *, NFSX_STATFS);
        sbp->f_type = MOUNT_NFS;
        sbp->f_flags = nmp->nm_flag;
        sbp->f_bsize = fxdr_unsigned(long, sfp->sf_tsize);
        sbp->f_fsize = fxdr_unsigned(long, sfp->sf_bsize);
        sbp->f_blocks = fxdr_unsigned(long, sfp->sf_blocks);
        sbp->f_bfree = fxdr_unsigned(long, sfp->sf_bfree);
        sbp->f_bavail = fxdr_unsigned(long, sfp->sf_bavail);
        sbp->f_files = 0;
        sbp->f_ffree = 0;
        if (sbp != &mp->mnt_stat) {
                bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
                bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
        }
        nfsm_reqdone;
        nfs_nput(vp);
        crfree(cred);
        return (error);
}

/*
 * Called by vfs_mountroot when nfs is going to be mounted as root
 * Not Yet (By a LONG shot)
 */
nfs_mountroot()
{
        return (ENODEV);
}

/*
 * VFS Operations.
 *
 * mount system call
 * It seems a bit dumb to copyinstr() the host and path here and then
 * bcopy() them in mountnfs(), but I wanted to detect errors before
 * doing the sockargs() call because sockargs() allocates an mbuf and
 * an error after that means that I have to release the mbuf.
 */
/* ARGSUSED */
nfs_mount(mp, path, data, ndp)
        struct mount *mp;
        char *path;
        caddr_t data;
        struct nameidata *ndp;
{
        int error;
        struct nfs_args args;
        struct mbuf *nam;
        char pth[MNAMELEN], hst[MNAMELEN];
        int len;
        nfsv2fh_t nfh;

        if (mp->mnt_flag & MNT_UPDATE)
                return (0);
        if (error = copyin(data, (caddr_t)&args, sizeof (struct nfs_args)))
                return (error);
        if (error=copyin((caddr_t)args.fh, (caddr_t)&nfh, sizeof (nfsv2fh_t)))
                return (error);
        if (error = copyinstr(path, pth, MNAMELEN-1, &len))
                return (error);
        bzero(&pth[len], MNAMELEN-len);
        if (error = copyinstr(args.hostname, hst, MNAMELEN-1, &len))
                return (error);
        bzero(&hst[len], MNAMELEN-len);
        /* sockargs() call must be after above copyin() calls */
        if (error = sockargs(&nam, (caddr_t)args.addr,
                sizeof (struct sockaddr), MT_SONAME))
                return (error);
        args.fh = &nfh;
        error = mountnfs(&args, mp, nam, pth, hst);
        return (error);
}

/*
 * Common code for mount and mountroot
 */
mountnfs(argp, mp, nam, pth, hst)
        register struct nfs_args *argp;
        register struct mount *mp;
        struct mbuf *nam;
        char *pth, *hst;
{
        register struct nfsmount *nmp;
        struct nfsnode *np;
        int error;
        fsid_t tfsid;

        MALLOC(nmp, struct nfsmount *, sizeof *nmp, M_NFSMNT, M_WAITOK);
        bzero((caddr_t)nmp, sizeof *nmp);
        mp->mnt_data = (qaddr_t)nmp;
        /*
         * Generate a unique nfs mount id. The problem is that a dev number
         * is not unique across multiple systems. The techique is as follows:
         * 1) Set to nblkdev,0 which will never be used otherwise
         * 2) Generate a first guess as nblkdev,nfs_mntid where nfs_mntid is
         *      NOT 0
         * 3) Loop searching the mount list for another one with same id
         *      If a match, increment val[0] and try again
         * NB: I increment val[0] { a long } instead of nfs_mntid { a u_char }
         *      so that nfs is not limited to 255 mount points
         *     Incrementing the high order bits does no real harm, since it
         *     simply makes the major dev number tick up. The upper bound is
         *     set to major dev 127 to avoid any sign extention problems
         */
        mp->mnt_stat.f_fsid.val[0] = makedev(nblkdev, 0);
        mp->mnt_stat.f_fsid.val[1] = MOUNT_NFS;
        if (++nfs_mntid == 0)
                ++nfs_mntid;
        tfsid.val[0] = makedev(nblkdev, nfs_mntid);
        tfsid.val[1] = MOUNT_NFS;
        while (getvfs(&tfsid)) {
                tfsid.val[0]++;
                nfs_mntid++;
        }
        if (major(tfsid.val[0]) > 127) {
                error = ENOENT;
                goto bad;
        }
        mp->mnt_stat.f_fsid.val[0] = tfsid.val[0];
        nmp->nm_mountp = mp;
        nmp->nm_flag = argp->flags;
        nmp->nm_rto = NFS_TIMEO;
        nmp->nm_rtt = -1;
        nmp->nm_rttvar = nmp->nm_rto << 1;
        nmp->nm_retry = NFS_RETRANS;
        nmp->nm_wsize = NFS_WSIZE;
        nmp->nm_rsize = NFS_RSIZE;
        bcopy((caddr_t)argp->fh, (caddr_t)&nmp->nm_fh, sizeof(nfsv2fh_t));
        mp->mnt_stat.f_type = MOUNT_NFS;
        bcopy(hst, mp->mnt_stat.f_mntfromname, MNAMELEN);
        bcopy(pth, mp->mnt_stat.f_mntonname, MNAMELEN);
        nmp->nm_nam = nam;

        if ((argp->flags & NFSMNT_TIMEO) && argp->timeo > 0) {
                nmp->nm_rto = argp->timeo;
                /* NFS timeouts are specified in 1/10 sec. */
                nmp->nm_rto = (nmp->nm_rto * 10) / NFS_HZ;
                if (nmp->nm_rto < NFS_MINTIMEO)
                        nmp->nm_rto = NFS_MINTIMEO;
                else if (nmp->nm_rto > NFS_MAXTIMEO)
                        nmp->nm_rto = NFS_MAXTIMEO;
                nmp->nm_rttvar = nmp->nm_rto << 1;
        }

        if ((argp->flags & NFSMNT_RETRANS) && argp->retrans >= 0) {
                nmp->nm_retry = argp->retrans;
                if (nmp->nm_retry > NFS_MAXREXMIT)
                        nmp->nm_retry = NFS_MAXREXMIT;
        }

        if ((argp->flags & NFSMNT_WSIZE) && argp->wsize > 0) {
                nmp->nm_wsize = argp->wsize;
                /* Round down to multiple of blocksize */
                nmp->nm_wsize &= ~0x1ff;
                if (nmp->nm_wsize <= 0)
                        nmp->nm_wsize = 512;
                else if (nmp->nm_wsize > NFS_MAXDATA)
                        nmp->nm_wsize = NFS_MAXDATA;
        }

        if ((argp->flags & NFSMNT_RSIZE) && argp->rsize > 0) {
                nmp->nm_rsize = argp->rsize;
                /* Round down to multiple of blocksize */
                nmp->nm_rsize &= ~0x1ff;
                if (nmp->nm_rsize <= 0)
                        nmp->nm_rsize = 512;
                else if (nmp->nm_rsize > NFS_MAXDATA)
                        nmp->nm_rsize = NFS_MAXDATA;
        }
        /* Set up the sockets and per-host congestion */
        nmp->nm_sotype = argp->sotype;
        nmp->nm_soproto = argp->proto;
        if (error = nfs_connect(nmp))
                goto bad;

        if (error = nfs_statfs(mp, &mp->mnt_stat))
                goto bad;
        /*
         * A reference count is needed on the nfsnode representing the
         * remote root.  If this object is not persistent, then backward
         * traversals of the mount point (i.e. "..") will not work if
         * the nfsnode gets flushed out of the cache. Ufs does not have
         * this problem, because one can identify root inodes by their
         * number == ROOTINO (2).
         */
        if (error = nfs_nget(mp, &nmp->nm_fh, &np))
                goto bad;
        /*
         * Unlock it, but keep the reference count.
         */
        nfs_unlock(NFSTOV(np));

        return (0);
bad:
        nfs_disconnect(nmp);
        FREE(nmp, M_NFSMNT);
        m_freem(nam);
        return (error);
}

/*
 * unmount system call
 */
nfs_unmount(mp, mntflags)
        struct mount *mp;
        int mntflags;
{
        register struct nfsmount *nmp;
        struct nfsnode *np;
        struct vnode *vp;
        int flags = 0;
        int error;

        if (mntflags & MNT_FORCE)
                return (EINVAL);
        if (mntflags & MNT_FORCE)
                flags |= FORCECLOSE;
        nmp = VFSTONFS(mp);
        /*
         * Clear out the buffer cache
         */
        mntflushbuf(mp, 0);
        if (mntinvalbuf(mp))
                return (EBUSY);
        /*
         * Goes something like this..
         * - Check for activity on the root vnode (other than ourselves).
         * - Call vflush() to clear out vnodes for this file system,
         *   except for the root vnode.
         * - Decrement reference on the vnode representing remote root.
         * - Close the socket
         * - Free up the data structures
         */
        /*
         * We need to decrement the ref. count on the nfsnode representing
         * the remote root.  See comment in mountnfs().  The VFS unmount()
         * has done vput on this vnode, otherwise we would get deadlock!
         */
        if (error = nfs_nget(mp, &nmp->nm_fh, &np))
                return(error);
        vp = NFSTOV(np);
        if (vp->v_usecount > 2) {
                vput(vp);
                return (EBUSY);
        }
        if (error = vflush(mp, vp, flags)) {
                vput(vp);
                return (error);
        }
        /*
         * Get rid of two reference counts, and unlock it on the second.
         */
        vrele(vp);
        vput(vp);
        nfs_disconnect(nmp);
        m_freem(nmp->nm_nam);
        free((caddr_t)nmp, M_NFSMNT);
        return (0);
}

/*
 * Return root of a filesystem
 */
nfs_root(mp, vpp)
        struct mount *mp;
        struct vnode **vpp;
{
        register struct vnode *vp;
        struct nfsmount *nmp;
        struct nfsnode *np;
        int error;

        nmp = VFSTONFS(mp);
        if (error = nfs_nget(mp, &nmp->nm_fh, &np))
                return (error);
        vp = NFSTOV(np);
        vp->v_type = VDIR;
        vp->v_flag = VROOT;
        *vpp = vp;
        return (0);
}

extern int syncprt;

/*
 * Flush out the buffer cache
 */
/* ARGSUSED */
nfs_sync(mp, waitfor)
        struct mount *mp;
        int waitfor;
{
        if (syncprt)
                bufstats();
        /*
         * Force stale buffer cache information to be flushed.
         */
        mntflushbuf(mp, waitfor == MNT_WAIT ? B_SYNC : 0);
        return (0);
}

/*
 * At this point, this should never happen
 */
/* ARGSUSED */
nfs_fhtovp(mp, fhp, vpp)
        struct mount *mp;
        struct fid *fhp;
        struct vnode **vpp;
{

        return (EINVAL);
}

/*
 * Vnode pointer to File handle, should never happen either
 */
/* ARGSUSED */
nfs_vptofh(mp, fhp, vpp)
        struct mount *mp;
        struct fid *fhp;
        struct vnode **vpp;
{

        return (EINVAL);
}

/*
 * Vfs start routine, a no-op.
 */
/* ARGSUSED */
nfs_start(mp, flags)
        struct mount *mp;
        int flags;
{

        return (0);
}

/*
 * Do operations associated with quotas, not supported
 */
nfs_quotactl(mp, cmd, uid, arg)
        struct mount *mp;
        int cmd;
        uid_t uid;
        caddr_t arg;
{
#ifdef lint
        mp = mp; cmd = cmd; uid = uid; arg = arg;
#endif /* lint */
        return (EOPNOTSUPP);
}