/*

   * NFS server file handle treatment.
   *
   * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
   * Portions Copyright (C) 1999 G. Allen Morris III <gam3@acm.org>
   * Extensive rewrite by Neil Brown <neilb@cse.unsw.edu.au> Southern-Spring 1999
   * ... and again Southern-Winter 2001 to support export_operations
   */

  #include <linux/exportfs.h>

  #include <linux/sunrpc/svcauth_gss.h>

  #include "nfsd.h"

  #include "vfs.h"

  #include "auth.h"

  
  #define NFSDDBG_FACILITY		NFSDDBG_FH

  /*
   * our acceptability function.
   * if NOSUBTREECHECK, accept anything
   * if not, require that we can walk up to exp->ex_dentry
   * doing some checks on the 'x' bits
   */
  static int nfsd_acceptable(void *expv, struct dentry *dentry)
  {
  	struct svc_export *exp = expv;
  	int rv;
  	struct dentry *tdentry;
  	struct dentry *parent;
  
  	if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
  		return 1;
  
  	tdentry = dget(dentry);

  	while (tdentry != exp->ex_path.dentry && !IS_ROOT(tdentry)) {

  		/* make sure parents give x permission to user */
  		int err;
  		parent = dget_parent(tdentry);

  		err = inode_permission(d_inode(parent), MAY_EXEC);

  		if (err < 0) {
  			dput(parent);
  			break;
  		}
  		dput(tdentry);
  		tdentry = parent;
  	}

  	if (tdentry != exp->ex_path.dentry)

  		dprintk("nfsd_acceptable failed at %p %pd
  ", tdentry, tdentry);

  	rv = (tdentry == exp->ex_path.dentry);

  	dput(tdentry);
  	return rv;
  }
  
  /* Type check. The correct error return for type mismatches does not seem to be
   * generally agreed upon. SunOS seems to use EISDIR if file isn't S_IFREG; a
   * comment in the NFSv3 spec says this is incorrect (implementation notes for
   * the write call).
   */

  static inline __be32

  nfsd_mode_check(struct svc_rqst *rqstp, struct dentry *dentry,
  		umode_t requested)

  {

  	umode_t mode = d_inode(dentry)->i_mode & S_IFMT;

  
  	if (requested == 0) /* the caller doesn't care */
  		return nfs_ok;

  	if (mode == requested) {
  		if (mode == S_IFDIR && !d_can_lookup(dentry)) {
  			WARN_ON_ONCE(1);
  			return nfserr_notdir;
  		}

  		return nfs_ok;

  	}

  	/*
  	 * v4 has an error more specific than err_notdir which we should
  	 * return in preference to err_notdir:
  	 */
  	if (rqstp->rq_vers == 4 && mode == S_IFLNK)
  		return nfserr_symlink;
  	if (requested == S_IFDIR)
  		return nfserr_notdir;
  	if (mode == S_IFDIR)
  		return nfserr_isdir;
  	return nfserr_inval;

  }

  static __be32 nfsd_setuser_and_check_port(struct svc_rqst *rqstp,
  					  struct svc_export *exp)
  {

  	int flags = nfsexp_flags(rqstp, exp);

  	/* Check if the request originated from a secure port. */

  	if (!test_bit(RQ_SECURE, &rqstp->rq_flags) && !(flags & NFSEXP_INSECURE_PORT)) {

  		RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);

  		dprintk("nfsd: request from insecure port %s!
  ",
  		        svc_print_addr(rqstp, buf, sizeof(buf)));

  		return nfserr_perm;
  	}
  
  	/* Set user creds for this exportpoint */
  	return nfserrno(nfsd_setuser(rqstp, exp));
  }

  static inline __be32 check_pseudo_root(struct svc_rqst *rqstp,
  	struct dentry *dentry, struct svc_export *exp)
  {
  	if (!(exp->ex_flags & NFSEXP_V4ROOT))
  		return nfs_ok;
  	/*
  	 * v2/v3 clients have no need for the V4ROOT export--they use
  	 * the mount protocl instead; also, further V4ROOT checks may be
  	 * in v4-specific code, in which case v2/v3 clients could bypass
  	 * them.
  	 */
  	if (!nfsd_v4client(rqstp))
  		return nfserr_stale;
  	/*
  	 * We're exposing only the directories and symlinks that have to be
  	 * traversed on the way to real exports:
  	 */

  	if (unlikely(!d_is_dir(dentry) &&
  		     !d_is_symlink(dentry)))

  		return nfserr_stale;
  	/*
  	 * A pseudoroot export gives permission to access only one
  	 * single directory; the kernel has to make another upcall
  	 * before granting access to anything else under it:
  	 */
  	if (unlikely(dentry != exp->ex_path.dentry))
  		return nfserr_stale;
  	return nfs_ok;
  }

  /*

   * Use the given filehandle to look up the corresponding export and
   * dentry.  On success, the results are used to set fh_export and
   * fh_dentry.
   */
  static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp)
  {
  	struct knfsd_fh	*fh = &fhp->fh_handle;
  	struct fid *fid = NULL, sfid;
  	struct svc_export *exp;
  	struct dentry *dentry;
  	int fileid_type;
  	int data_left = fh->fh_size/4;
  	__be32 error;
  
  	error = nfserr_stale;
  	if (rqstp->rq_vers > 2)
  		error = nfserr_badhandle;
  	if (rqstp->rq_vers == 4 && fh->fh_size == 0)
  		return nfserr_nofilehandle;
  
  	if (fh->fh_version == 1) {
  		int len;
  
  		if (--data_left < 0)
  			return error;
  		if (fh->fh_auth_type != 0)
  			return error;
  		len = key_len(fh->fh_fsid_type) / 4;
  		if (len == 0)
  			return error;
  		if  (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
  			/* deprecated, convert to type 3 */
  			len = key_len(FSID_ENCODE_DEV)/4;
  			fh->fh_fsid_type = FSID_ENCODE_DEV;

  			/*
  			 * struct knfsd_fh uses host-endian fields, which are
  			 * sometimes used to hold net-endian values. This
  			 * confuses sparse, so we must use __force here to
  			 * keep it from complaining.
  			 */
  			fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl((__force __be32)fh->fh_fsid[0]),
  							ntohl((__force __be32)fh->fh_fsid[1])));

  			fh->fh_fsid[1] = fh->fh_fsid[2];
  		}
  		data_left -= len;
  		if (data_left < 0)
  			return error;

  		exp = rqst_exp_find(rqstp, fh->fh_fsid_type, fh->fh_fsid);
  		fid = (struct fid *)(fh->fh_fsid + len);

  	} else {
  		__u32 tfh[2];
  		dev_t xdev;
  		ino_t xino;
  
  		if (fh->fh_size != NFS_FHSIZE)
  			return error;
  		/* assume old filehandle format */
  		xdev = old_decode_dev(fh->ofh_xdev);
  		xino = u32_to_ino_t(fh->ofh_xino);
  		mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
  		exp = rqst_exp_find(rqstp, FSID_DEV, tfh);
  	}
  
  	error = nfserr_stale;
  	if (PTR_ERR(exp) == -ENOENT)
  		return error;
  
  	if (IS_ERR(exp))
  		return nfserrno(PTR_ERR(exp));

  	if (exp->ex_flags & NFSEXP_NOSUBTREECHECK) {
  		/* Elevate privileges so that the lack of 'r' or 'x'
  		 * permission on some parent directory will
  		 * not stop exportfs_decode_fh from being able
  		 * to reconnect a directory into the dentry cache.
  		 * The same problem can affect "SUBTREECHECK" exports,
  		 * but as nfsd_acceptable depends on correct
  		 * access control settings being in effect, we cannot
  		 * fix that case easily.
  		 */

  		struct cred *new = prepare_creds();

  		if (!new) {
  			error =  nfserrno(-ENOMEM);
  			goto out;
  		}

  		new->cap_effective =
  			cap_raise_nfsd_set(new->cap_effective,
  					   new->cap_permitted);
  		put_cred(override_creds(new));
  		put_cred(new);

  	} else {
  		error = nfsd_setuser_and_check_port(rqstp, exp);
  		if (error)
  			goto out;
  	}

  
  	/*
  	 * Look up the dentry using the NFS file handle.
  	 */
  	error = nfserr_stale;
  	if (rqstp->rq_vers > 2)
  		error = nfserr_badhandle;
  
  	if (fh->fh_version != 1) {
  		sfid.i32.ino = fh->ofh_ino;
  		sfid.i32.gen = fh->ofh_generation;
  		sfid.i32.parent_ino = fh->ofh_dirino;
  		fid = &sfid;
  		data_left = 3;
  		if (fh->ofh_dirino == 0)
  			fileid_type = FILEID_INO32_GEN;
  		else
  			fileid_type = FILEID_INO32_GEN_PARENT;
  	} else
  		fileid_type = fh->fh_fileid_type;
  
  	if (fileid_type == FILEID_ROOT)
  		dentry = dget(exp->ex_path.dentry);
  	else {
  		dentry = exportfs_decode_fh(exp->ex_path.mnt, fid,
  				data_left, fileid_type,
  				nfsd_acceptable, exp);
  	}
  	if (dentry == NULL)
  		goto out;
  	if (IS_ERR(dentry)) {
  		if (PTR_ERR(dentry) != -EINVAL)
  			error = nfserrno(PTR_ERR(dentry));
  		goto out;
  	}

  	if (d_is_dir(dentry) &&

  			(dentry->d_flags & DCACHE_DISCONNECTED)) {

  		printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %pd2
  ",
  				dentry);

  	}
  
  	fhp->fh_dentry = dentry;
  	fhp->fh_export = exp;

  	return 0;
  out:
  	exp_put(exp);
  	return error;
  }

  /**
   * fh_verify - filehandle lookup and access checking
   * @rqstp: pointer to current rpc request
   * @fhp: filehandle to be verified
   * @type: expected type of object pointed to by filehandle
   * @access: type of access needed to object
   *
   * Look up a dentry from the on-the-wire filehandle, check the client's
   * access to the export, and set the current task's credentials.
   *
   * Regardless of success or failure of fh_verify(), fh_put() should be
   * called on @fhp when the caller is finished with the filehandle.
   *
   * fh_verify() may be called multiple times on a given filehandle, for
   * example, when processing an NFSv4 compound.  The first call will look
   * up a dentry using the on-the-wire filehandle.  Subsequent calls will
   * skip the lookup and just perform the other checks and possibly change
   * the current task's credentials.

   *

   * @type specifies the type of object expected using one of the S_IF*
   * constants defined in include/linux/stat.h.  The caller may use zero
   * to indicate that it doesn't care, or a negative integer to indicate
   * that it expects something not of the given type.

   *

   * @access is formed from the NFSD_MAY_* constants defined in

   * fs/nfsd/vfs.h.

   */

  __be32

  fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type, int access)

  {

  	struct svc_export *exp;

  	struct dentry	*dentry;

  	__be32		error;

  
  	dprintk("nfsd: fh_verify(%s)
  ", SVCFH_fmt(fhp));

  	if (!fhp->fh_dentry) {

  		error = nfsd_set_fh_dentry(rqstp, fhp);

  		if (error)
  			goto out;

  	}

  	dentry = fhp->fh_dentry;
  	exp = fhp->fh_export;
  	/*
  	 * We still have to do all these permission checks, even when
  	 * fh_dentry is already set:
  	 * 	- fh_verify may be called multiple times with different
  	 * 	  "access" arguments (e.g. nfsd_proc_create calls
  	 * 	  fh_verify(...,NFSD_MAY_EXEC) first, then later (in
  	 * 	  nfsd_create) calls fh_verify(...,NFSD_MAY_CREATE).
  	 *	- in the NFSv4 case, the filehandle may have been filled
  	 *	  in by fh_compose, and given a dentry, but further
  	 *	  compound operations performed with that filehandle
  	 *	  still need permissions checks.  In the worst case, a
  	 *	  mountpoint crossing may have changed the export
  	 *	  options, and we may now need to use a different uid
  	 *	  (for example, if different id-squashing options are in
  	 *	  effect on the new filesystem).
  	 */

  	error = check_pseudo_root(rqstp, dentry, exp);
  	if (error)
  		goto out;

  	error = nfsd_setuser_and_check_port(rqstp, exp);
  	if (error)
  		goto out;

  	error = nfsd_mode_check(rqstp, dentry, type);

  	if (error)
  		goto out;

  	/*
  	 * pseudoflavor restrictions are not enforced on NLM,
  	 * which clients virtually always use auth_sys for,
  	 * even while using RPCSEC_GSS for NFS.
  	 */

  	if (access & NFSD_MAY_LOCK || access & NFSD_MAY_BYPASS_GSS)

  		goto skip_pseudoflavor_check;
  	/*
  	 * Clients may expect to be able to use auth_sys during mount,
  	 * even if they use gss for everything else; see section 2.3.2
  	 * of rfc 2623.
  	 */
  	if (access & NFSD_MAY_BYPASS_GSS_ON_ROOT
  			&& exp->ex_path.dentry == dentry)
  		goto skip_pseudoflavor_check;
  
  	error = check_nfsd_access(exp, rqstp);
  	if (error)
  		goto out;

  skip_pseudoflavor_check:

  	/* Finally, check access permissions. */

  	error = nfsd_permission(rqstp, exp, dentry, access);

  	if (error) {

  		dprintk("fh_verify: %pd2 permission failure, "

  			"acc=%x, error=%d
  ",

  			dentry,

  			access, ntohl(error));

  	}

  out:

  	if (error == nfserr_stale)
  		nfsdstats.fh_stale++;
  	return error;
  }
  
  
  /*
   * Compose a file handle for an NFS reply.
   *
   * Note that when first composed, the dentry may not yet have
   * an inode.  In this case a call to fh_update should be made
   * before the fh goes out on the wire ...
   */

  static void _fh_update(struct svc_fh *fhp, struct svc_export *exp,
  		struct dentry *dentry)

  {

  	if (dentry != exp->ex_path.dentry) {

  		struct fid *fid = (struct fid *)

  			(fhp->fh_handle.fh_fsid + fhp->fh_handle.fh_size/4 - 1);

  		int maxsize = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
  		int subtreecheck = !(exp->ex_flags & NFSEXP_NOSUBTREECHECK);

  		fhp->fh_handle.fh_fileid_type =
  			exportfs_encode_fh(dentry, fid, &maxsize, subtreecheck);
  		fhp->fh_handle.fh_size += maxsize * 4;
  	} else {
  		fhp->fh_handle.fh_fileid_type = FILEID_ROOT;
  	}

  }
  
  /*
   * for composing old style file handles
   */
  static inline void _fh_update_old(struct dentry *dentry,
  				  struct svc_export *exp,
  				  struct knfsd_fh *fh)
  {

  	fh->ofh_ino = ino_t_to_u32(d_inode(dentry)->i_ino);
  	fh->ofh_generation = d_inode(dentry)->i_generation;

  	if (d_is_dir(dentry) ||

  	    (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
  		fh->ofh_dirino = 0;
  }

  static bool is_root_export(struct svc_export *exp)
  {
  	return exp->ex_path.dentry == exp->ex_path.dentry->d_sb->s_root;
  }
  
  static struct super_block *exp_sb(struct svc_export *exp)
  {

  	return exp->ex_path.dentry->d_sb;

  }
  
  static bool fsid_type_ok_for_exp(u8 fsid_type, struct svc_export *exp)
  {
  	switch (fsid_type) {
  	case FSID_DEV:
  		if (!old_valid_dev(exp_sb(exp)->s_dev))
  			return 0;
  		/* FALL THROUGH */
  	case FSID_MAJOR_MINOR:
  	case FSID_ENCODE_DEV:
  		return exp_sb(exp)->s_type->fs_flags & FS_REQUIRES_DEV;
  	case FSID_NUM:
  		return exp->ex_flags & NFSEXP_FSID;
  	case FSID_UUID8:
  	case FSID_UUID16:
  		if (!is_root_export(exp))
  			return 0;
  		/* fall through */
  	case FSID_UUID4_INUM:
  	case FSID_UUID16_INUM:
  		return exp->ex_uuid != NULL;
  	}
  	return 1;
  }

  static void set_version_and_fsid_type(struct svc_fh *fhp, struct svc_export *exp, struct svc_fh *ref_fh)
  {

  	u8 version;

  	u8 fsid_type;
  retry:

  	version = 1;

  	if (ref_fh && ref_fh->fh_export == exp) {

  		version = ref_fh->fh_handle.fh_version;

  		fsid_type = ref_fh->fh_handle.fh_fsid_type;

  		ref_fh = NULL;
  
  		switch (version) {
  		case 0xca:

  			fsid_type = FSID_DEV;

  			break;
  		case 1:
  			break;
  		default:
  			goto retry;
  		}

  		/*
  		 * As the fsid -> filesystem mapping was guided by
  		 * user-space, there is no guarantee that the filesystem
  		 * actually supports that fsid type. If it doesn't we
  		 * loop around again without ref_fh set.

  		 */

  		if (!fsid_type_ok_for_exp(fsid_type, exp))
  			goto retry;

  	} else if (exp->ex_flags & NFSEXP_FSID) {
  		fsid_type = FSID_NUM;

  	} else if (exp->ex_uuid) {
  		if (fhp->fh_maxsize >= 64) {

  			if (is_root_export(exp))

  				fsid_type = FSID_UUID16;
  			else
  				fsid_type = FSID_UUID16_INUM;
  		} else {

  			if (is_root_export(exp))

  				fsid_type = FSID_UUID8;
  			else
  				fsid_type = FSID_UUID4_INUM;
  		}

  	} else if (!old_valid_dev(exp_sb(exp)->s_dev))

  		/* for newer device numbers, we must use a newer fsid format */

  		fsid_type = FSID_ENCODE_DEV;

  	else

  		fsid_type = FSID_DEV;

  	fhp->fh_handle.fh_version = version;
  	if (version)
  		fhp->fh_handle.fh_fsid_type = fsid_type;
  }
  
  __be32
  fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
  	   struct svc_fh *ref_fh)
  {
  	/* ref_fh is a reference file handle.
  	 * if it is non-null and for the same filesystem, then we should compose
  	 * a filehandle which is of the same version, where possible.
  	 * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
  	 * Then create a 32byte filehandle using nfs_fhbase_old
  	 *
  	 */

  	struct inode * inode = d_inode(dentry);

  	dev_t ex_dev = exp_sb(exp)->s_dev;

  	dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %pd2, ino=%ld)
  ",

  		MAJOR(ex_dev), MINOR(ex_dev),

  		(long) d_inode(exp->ex_path.dentry)->i_ino,

  		dentry,

  		(inode ? inode->i_ino : 0));
  
  	/* Choose filehandle version and fsid type based on
  	 * the reference filehandle (if it is in the same export)
  	 * or the export options.
  	 */

  	set_version_and_fsid_type(fhp, exp, ref_fh);

  
  	if (ref_fh == fhp)
  		fh_put(ref_fh);
  
  	if (fhp->fh_locked || fhp->fh_dentry) {

  		printk(KERN_ERR "fh_compose: fh %pd2 not initialized!
  ",
  		       dentry);

  	}
  	if (fhp->fh_maxsize < NFS_FHSIZE)

  		printk(KERN_ERR "fh_compose: called with maxsize %d! %pd2
  ",

  		       fhp->fh_maxsize,

  		       dentry);

  
  	fhp->fh_dentry = dget(dentry); /* our internal copy */

  	fhp->fh_export = exp_get(exp);

  	if (fhp->fh_handle.fh_version == 0xca) {

  		/* old style filehandle please */
  		memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
  		fhp->fh_handle.fh_size = NFS_FHSIZE;
  		fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
  		fhp->fh_handle.ofh_dev =  old_encode_dev(ex_dev);
  		fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;

  		fhp->fh_handle.ofh_xino =

  			ino_t_to_u32(d_inode(exp->ex_path.dentry)->i_ino);

  		fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
  		if (inode)
  			_fh_update_old(dentry, exp, &fhp->fh_handle);
  	} else {

  		fhp->fh_handle.fh_size =
  			key_len(fhp->fh_handle.fh_fsid_type) + 4;

  		fhp->fh_handle.fh_auth_type = 0;

  
  		mk_fsid(fhp->fh_handle.fh_fsid_type,
  			fhp->fh_handle.fh_fsid,
  			ex_dev,

  			d_inode(exp->ex_path.dentry)->i_ino,

  			exp->ex_fsid, exp->ex_uuid);

  		if (inode)
  			_fh_update(fhp, exp, dentry);

  		if (fhp->fh_handle.fh_fileid_type == FILEID_INVALID) {

  			fh_put(fhp);

  			return nfserr_opnotsupp;

  		}

  	}

  	return 0;
  }
  
  /*
   * Update file handle information after changing a dentry.
   * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
   */

  __be32

  fh_update(struct svc_fh *fhp)
  {
  	struct dentry *dentry;

  	if (!fhp->fh_dentry)
  		goto out_bad;
  
  	dentry = fhp->fh_dentry;

  	if (d_really_is_negative(dentry))

  		goto out_negative;
  	if (fhp->fh_handle.fh_version != 1) {
  		_fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
  	} else {

  		if (fhp->fh_handle.fh_fileid_type != FILEID_ROOT)

  			return 0;

  
  		_fh_update(fhp, fhp->fh_export, dentry);

  		if (fhp->fh_handle.fh_fileid_type == FILEID_INVALID)

  			return nfserr_opnotsupp;
  	}

  	return 0;

  out_bad:
  	printk(KERN_ERR "fh_update: fh not verified!
  ");

  	return nfserr_serverfault;

  out_negative:

  	printk(KERN_ERR "fh_update: %pd2 still negative!
  ",
  		dentry);

  	return nfserr_serverfault;

  }
  
  /*
   * Release a file handle.
   */
  void
  fh_put(struct svc_fh *fhp)
  {
  	struct dentry * dentry = fhp->fh_dentry;
  	struct svc_export * exp = fhp->fh_export;
  	if (dentry) {
  		fh_unlock(fhp);
  		fhp->fh_dentry = NULL;
  		dput(dentry);

  		fh_clear_wcc(fhp);

  	}

  	fh_drop_write(fhp);

  	if (exp) {

  		exp_put(exp);

  		fhp->fh_export = NULL;
  	}
  	return;
  }
  
  /*
   * Shorthand for dprintk()'s
   */
  char * SVCFH_fmt(struct svc_fh *fhp)
  {
  	struct knfsd_fh *fh = &fhp->fh_handle;
  
  	static char buf[80];
  	sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
  		fh->fh_size,
  		fh->fh_base.fh_pad[0],
  		fh->fh_base.fh_pad[1],
  		fh->fh_base.fh_pad[2],
  		fh->fh_base.fh_pad[3],
  		fh->fh_base.fh_pad[4],
  		fh->fh_base.fh_pad[5]);
  	return buf;
  }

  
  enum fsid_source fsid_source(struct svc_fh *fhp)
  {
  	if (fhp->fh_handle.fh_version != 1)
  		return FSIDSOURCE_DEV;
  	switch(fhp->fh_handle.fh_fsid_type) {
  	case FSID_DEV:
  	case FSID_ENCODE_DEV:
  	case FSID_MAJOR_MINOR:

  		if (exp_sb(fhp->fh_export)->s_type->fs_flags & FS_REQUIRES_DEV)

  			return FSIDSOURCE_DEV;
  		break;

  	case FSID_NUM:

  		if (fhp->fh_export->ex_flags & NFSEXP_FSID)
  			return FSIDSOURCE_FSID;

  		break;
  	default:
  		break;

  	}

  	/* either a UUID type filehandle, or the filehandle doesn't
  	 * match the export.
  	 */
  	if (fhp->fh_export->ex_flags & NFSEXP_FSID)
  		return FSIDSOURCE_FSID;
  	if (fhp->fh_export->ex_uuid)
  		return FSIDSOURCE_UUID;
  	return FSIDSOURCE_DEV;

  }