nfs_vfsops.c

早期freebsd实现

	/* sockargs() call must be after above copyin() calls */
	if (error = sockargs(&nam, (caddr_t)args.addr,
		args.addrlen, MT_SONAME))
		return (error);
	args.fh = &nfh;
	error = mountnfs(&args, mp, nam, pth, hst, &vp);
	return (error);
}

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

	if (mp->mnt_flag & MNT_UPDATE) {
		nmp = VFSTONFS(mp);
		/* update paths, file handles, etc, here	XXX */
		m_freem(nam);
		return (0);
	} else {
		MALLOC(nmp, struct nfsmount *, sizeof (struct nfsmount),
		    M_NFSMNT, M_WAITOK);
		bzero((caddr_t)nmp, sizeof (struct nfsmount));
		mp->mnt_data = (qaddr_t)nmp;
	}
	getnewfsid(mp, MOUNT_NFS);
	nmp->nm_mountp = mp;
	nmp->nm_flag = argp->flags;
	if ((nmp->nm_flag & (NFSMNT_NQNFS | NFSMNT_MYWRITE)) ==
		(NFSMNT_NQNFS | NFSMNT_MYWRITE)) {
		error = EPERM;
		goto bad;
	}
	if (nmp->nm_flag & NFSMNT_NQNFS)
		/*
		 * We have to set mnt_maxsymlink to a non-zero value so
		 * that COMPAT_43 routines will know that we are setting
		 * the d_type field in directories (and can zero it for
		 * unsuspecting binaries).
		 */
		mp->mnt_maxsymlinklen = 1;
	nmp->nm_timeo = NFS_TIMEO;
	nmp->nm_retry = NFS_RETRANS;
	nmp->nm_wsize = NFS_WSIZE;
	nmp->nm_rsize = NFS_RSIZE;
	nmp->nm_numgrps = NFS_MAXGRPS;
	nmp->nm_readahead = NFS_DEFRAHEAD;
	nmp->nm_leaseterm = NQ_DEFLEASE;
	nmp->nm_deadthresh = NQ_DEADTHRESH;
	nmp->nm_tnext = (struct nfsnode *)nmp;
	nmp->nm_tprev = (struct nfsnode *)nmp;
	nmp->nm_inprog = NULLVP;
	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_timeo = (argp->timeo * NFS_HZ + 5) / 10;
		if (nmp->nm_timeo < NFS_MINTIMEO)
			nmp->nm_timeo = NFS_MINTIMEO;
		else if (nmp->nm_timeo > NFS_MAXTIMEO)
			nmp->nm_timeo = NFS_MAXTIMEO;
	}

	if ((argp->flags & NFSMNT_RETRANS) && argp->retrans > 1) {
		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 (nmp->nm_wsize > MAXBSIZE)
		nmp->nm_wsize = MAXBSIZE;

	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;
	}
	if (nmp->nm_rsize > MAXBSIZE)
		nmp->nm_rsize = MAXBSIZE;
	if ((argp->flags & NFSMNT_MAXGRPS) && argp->maxgrouplist >= 0 &&
		argp->maxgrouplist <= NFS_MAXGRPS)
		nmp->nm_numgrps = argp->maxgrouplist;
	if ((argp->flags & NFSMNT_READAHEAD) && argp->readahead >= 0 &&
		argp->readahead <= NFS_MAXRAHEAD)
		nmp->nm_readahead = argp->readahead;
	if ((argp->flags & NFSMNT_LEASETERM) && argp->leaseterm >= 2 &&
		argp->leaseterm <= NQ_MAXLEASE)
		nmp->nm_leaseterm = argp->leaseterm;
	if ((argp->flags & NFSMNT_DEADTHRESH) && argp->deadthresh >= 1 &&
		argp->deadthresh <= NQ_NEVERDEAD)
		nmp->nm_deadthresh = argp->deadthresh;
	/* Set up the sockets and per-host congestion */
	nmp->nm_sotype = argp->sotype;
	nmp->nm_soproto = argp->proto;

	/*
	 * For Connection based sockets (TCP,...) defer the connect until
	 * the first request, in case the server is not responding.
	 */
	if (nmp->nm_sotype == SOCK_DGRAM &&
		(error = nfs_connect(nmp, (struct nfsreq *)0)))
		goto bad;

	/*
	 * This is silly, but it has to be set so that vinifod() works.
	 * We do not want to do an nfs_statfs() here since we can get
	 * stuck on a dead server and we are holding a lock on the mount
	 * point.
	 */
	mp->mnt_stat.f_iosize = NFS_MAXDGRAMDATA;
	/*
	 * 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;
	*vpp = NFSTOV(np);

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

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

	if (mntflags & MNT_FORCE) {
		if (!doforce || (mp->mnt_flag & MNT_ROOTFS))
			return (EINVAL);
		flags |= FORCECLOSE;
	}
	nmp = VFSTONFS(mp);
	/*
	 * 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);
	}

	/*
	 * Must handshake with nqnfs_clientd() if it is active.
	 */
	nmp->nm_flag |= NFSMNT_DISMINPROG;
	while (nmp->nm_inprog != NULLVP)
		(void) tsleep((caddr_t)&lbolt, PSOCK, "nfsdism", 0);
	if (error = vflush(mp, vp, flags)) {
		vput(vp);
		nmp->nm_flag &= ~NFSMNT_DISMINPROG;
		return (error);
	}

	/*
	 * We are now committed to the unmount.
	 * For NQNFS, let the server daemon free the nfsmount structure.
	 */
	if (nmp->nm_flag & (NFSMNT_NQNFS | NFSMNT_KERB))
		nmp->nm_flag |= NFSMNT_DISMNT;

	/*
	 * There are two reference counts to get rid of here.
	 */
	vrele(vp);
	vrele(vp);
	vgone(vp);
	nfs_disconnect(nmp);
	m_freem(nmp->nm_nam);

	if ((nmp->nm_flag & (NFSMNT_NQNFS | NFSMNT_KERB)) == 0)
		free((caddr_t)nmp, M_NFSMNT);
	return (0);
}

/*
 * Return root of a filesystem
 */
int
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 */
int
nfs_sync(mp, waitfor, cred, p)
	struct mount *mp;
	int waitfor;
	struct ucred *cred;
	struct proc *p;
{
	register struct vnode *vp;
	int error, allerror = 0;

	/*
	 * Force stale buffer cache information to be flushed.
	 */
loop:
	for (vp = mp->mnt_vnodelist.lh_first;
	     vp != NULL;
	     vp = vp->v_mntvnodes.le_next) {
		/*
		 * 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) || vp->v_dirtyblkhd.lh_first == NULL)
			continue;
		if (vget(vp, 1))
			goto loop;
		if (error = VOP_FSYNC(vp, cred, waitfor, p))
			allerror = error;
		vput(vp);
	}
	return (allerror);
}

/*
 * NFS flat namespace lookup.
 * Currently unsupported.
 */
/* ARGSUSED */
int
nfs_vget(mp, ino, vpp)
	struct mount *mp;
	ino_t ino;
	struct vnode **vpp;
{

	return (EOPNOTSUPP);
}

/*
 * At this point, this should never happen
 */
/* ARGSUSED */
int
nfs_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;
{

	return (EINVAL);
}

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

	return (EINVAL);
}

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

	return (0);
}

/*
 * Do operations associated with quotas, not supported
 */
/* ARGSUSED */
int
nfs_quotactl(mp, cmd, uid, arg, p)
	struct mount *mp;
	int cmd;
	uid_t uid;
	caddr_t arg;
	struct proc *p;
{

	return (EOPNOTSUPP);
}