/*

   *  Common NFSv4 ACL handling code.
   *
   *  Copyright (c) 2002, 2003 The Regents of the University of Michigan.
   *  All rights reserved.
   *
   *  Marius Aamodt Eriksen <marius@umich.edu>
   *  Jeff Sedlak <jsedlak@umich.edu>
   *  J. Bruce Fields <bfields@umich.edu>
   *
   *  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. 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 ``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.
   */

  #include <linux/slab.h>

  #include <linux/nfs_fs.h>

  #include <linux/nfs4_acl.h>
  
  
  /* mode bit translations: */
  #define NFS4_READ_MODE (NFS4_ACE_READ_DATA)
  #define NFS4_WRITE_MODE (NFS4_ACE_WRITE_DATA | NFS4_ACE_APPEND_DATA)
  #define NFS4_EXECUTE_MODE NFS4_ACE_EXECUTE
  #define NFS4_ANYONE_MODE (NFS4_ACE_READ_ATTRIBUTES | NFS4_ACE_READ_ACL | NFS4_ACE_SYNCHRONIZE)
  #define NFS4_OWNER_MODE (NFS4_ACE_WRITE_ATTRIBUTES | NFS4_ACE_WRITE_ACL)
  
  /* We don't support these bits; insist they be neither allowed nor denied */
  #define NFS4_MASK_UNSUPP (NFS4_ACE_DELETE | NFS4_ACE_WRITE_OWNER \
  		| NFS4_ACE_READ_NAMED_ATTRS | NFS4_ACE_WRITE_NAMED_ATTRS)
  
  /* flags used to simulate posix default ACLs */
  #define NFS4_INHERITANCE_FLAGS (NFS4_ACE_FILE_INHERIT_ACE \

  		| NFS4_ACE_DIRECTORY_INHERIT_ACE)

  #define NFS4_SUPPORTED_FLAGS (NFS4_INHERITANCE_FLAGS \
  		| NFS4_ACE_INHERIT_ONLY_ACE \
  		| NFS4_ACE_IDENTIFIER_GROUP)

  #define MASK_EQUAL(mask1, mask2) \
  	( ((mask1) & NFS4_ACE_MASK_ALL) == ((mask2) & NFS4_ACE_MASK_ALL) )
  
  static u32
  mask_from_posix(unsigned short perm, unsigned int flags)
  {
  	int mask = NFS4_ANYONE_MODE;
  
  	if (flags & NFS4_ACL_OWNER)
  		mask |= NFS4_OWNER_MODE;
  	if (perm & ACL_READ)
  		mask |= NFS4_READ_MODE;
  	if (perm & ACL_WRITE)
  		mask |= NFS4_WRITE_MODE;
  	if ((perm & ACL_WRITE) && (flags & NFS4_ACL_DIR))
  		mask |= NFS4_ACE_DELETE_CHILD;
  	if (perm & ACL_EXECUTE)
  		mask |= NFS4_EXECUTE_MODE;
  	return mask;
  }
  
  static u32

  deny_mask_from_posix(unsigned short perm, u32 flags)

  {

  	u32 mask = 0;
  
  	if (perm & ACL_READ)
  		mask |= NFS4_READ_MODE;
  	if (perm & ACL_WRITE)
  		mask |= NFS4_WRITE_MODE;
  	if ((perm & ACL_WRITE) && (flags & NFS4_ACL_DIR))
  		mask |= NFS4_ACE_DELETE_CHILD;
  	if (perm & ACL_EXECUTE)
  		mask |= NFS4_EXECUTE_MODE;
  	return mask;

  }
  
  /* XXX: modify functions to return NFS errors; they're only ever
   * used by nfs code, after all.... */

  /* We only map from NFSv4 to POSIX ACLs when setting ACLs, when we err on the
   * side of being more restrictive, so the mode bit mapping below is
   * pessimistic.  An optimistic version would be needed to handle DENY's,
   * but we espect to coalesce all ALLOWs and DENYs before mapping to mode
   * bits. */
  
  static void
  low_mode_from_nfs4(u32 perm, unsigned short *mode, unsigned int flags)

  {

  	u32 write_mode = NFS4_WRITE_MODE;

  	if (flags & NFS4_ACL_DIR)
  		write_mode |= NFS4_ACE_DELETE_CHILD;

  	*mode = 0;
  	if ((perm & NFS4_READ_MODE) == NFS4_READ_MODE)
  		*mode |= ACL_READ;

  	if ((perm & write_mode) == write_mode)

  		*mode |= ACL_WRITE;
  	if ((perm & NFS4_EXECUTE_MODE) == NFS4_EXECUTE_MODE)
  		*mode |= ACL_EXECUTE;

  }
  
  struct ace_container {
  	struct nfs4_ace  *ace;
  	struct list_head  ace_l;
  };
  
  static short ace2type(struct nfs4_ace *);

  static void _posix_to_nfsv4_one(struct posix_acl *, struct nfs4_acl *,
  				unsigned int);

  
  struct nfs4_acl *
  nfs4_acl_posix_to_nfsv4(struct posix_acl *pacl, struct posix_acl *dpacl,
  			unsigned int flags)
  {
  	struct nfs4_acl *acl;

  	int size = 0;

  	if (pacl) {
  		if (posix_acl_valid(pacl) < 0)
  			return ERR_PTR(-EINVAL);
  		size += 2*pacl->a_count;

  	}

  	if (dpacl) {
  		if (posix_acl_valid(dpacl) < 0)
  			return ERR_PTR(-EINVAL);
  		size += 2*dpacl->a_count;

  	}

  	/* Allocate for worst case: one (deny, allow) pair each: */
  	acl = nfs4_acl_new(size);
  	if (acl == NULL)
  		return ERR_PTR(-ENOMEM);

  	if (pacl)
  		_posix_to_nfsv4_one(pacl, acl, flags & ~NFS4_ACL_TYPE_DEFAULT);

  	if (dpacl)
  		_posix_to_nfsv4_one(dpacl, acl, flags | NFS4_ACL_TYPE_DEFAULT);

  
  	return acl;
  }

  struct posix_acl_summary {
  	unsigned short owner;
  	unsigned short users;
  	unsigned short group;
  	unsigned short groups;
  	unsigned short other;
  	unsigned short mask;
  };

  static void

  summarize_posix_acl(struct posix_acl *acl, struct posix_acl_summary *pas)

  {

  	struct posix_acl_entry *pa, *pe;

  
  	/*
  	 * Only pas.users and pas.groups need initialization; previous
  	 * posix_acl_valid() calls ensure that the other fields will be
  	 * initialized in the following loop.  But, just to placate gcc:
  	 */
  	memset(pas, 0, sizeof(*pas));

  	pas->mask = 07;
  
  	pe = acl->a_entries + acl->a_count;
  
  	FOREACH_ACL_ENTRY(pa, acl, pe) {
  		switch (pa->e_tag) {
  			case ACL_USER_OBJ:
  				pas->owner = pa->e_perm;
  				break;
  			case ACL_GROUP_OBJ:
  				pas->group = pa->e_perm;
  				break;
  			case ACL_USER:
  				pas->users |= pa->e_perm;
  				break;
  			case ACL_GROUP:
  				pas->groups |= pa->e_perm;
  				break;
  			case ACL_OTHER:
  				pas->other = pa->e_perm;
  				break;
  			case ACL_MASK:
  				pas->mask = pa->e_perm;
  				break;
  		}
  	}
  	/* We'll only care about effective permissions: */
  	pas->users &= pas->mask;
  	pas->group &= pas->mask;
  	pas->groups &= pas->mask;

  }
  
  /* We assume the acl has been verified with posix_acl_valid. */

  static void

  _posix_to_nfsv4_one(struct posix_acl *pacl, struct nfs4_acl *acl,
  						unsigned int flags)
  {

  	struct posix_acl_entry *pa, *group_owner_entry;
  	struct nfs4_ace *ace;
  	struct posix_acl_summary pas;
  	unsigned short deny;

  	int eflag = ((flags & NFS4_ACL_TYPE_DEFAULT) ?

  		NFS4_INHERITANCE_FLAGS | NFS4_ACE_INHERIT_ONLY_ACE : 0);

  
  	BUG_ON(pacl->a_count < 3);

  	summarize_posix_acl(pacl, &pas);

  
  	pa = pacl->a_entries;

  	ace = acl->aces + acl->naces;
  
  	/* We could deny everything not granted by the owner: */
  	deny = ~pas.owner;
  	/*
  	 * but it is equivalent (and simpler) to deny only what is not
  	 * granted by later entries:
  	 */
  	deny &= pas.users | pas.group | pas.groups | pas.other;
  	if (deny) {
  		ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
  		ace->flag = eflag;
  		ace->access_mask = deny_mask_from_posix(deny, flags);
  		ace->whotype = NFS4_ACL_WHO_OWNER;
  		ace++;
  		acl->naces++;
  	}
  
  	ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
  	ace->flag = eflag;
  	ace->access_mask = mask_from_posix(pa->e_perm, flags | NFS4_ACL_OWNER);
  	ace->whotype = NFS4_ACL_WHO_OWNER;
  	ace++;
  	acl->naces++;

  	pa++;
  
  	while (pa->e_tag == ACL_USER) {

  		deny = ~(pa->e_perm & pas.mask);
  		deny &= pas.groups | pas.group | pas.other;
  		if (deny) {
  			ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
  			ace->flag = eflag;
  			ace->access_mask = deny_mask_from_posix(deny, flags);
  			ace->whotype = NFS4_ACL_WHO_NAMED;
  			ace->who = pa->e_id;
  			ace++;
  			acl->naces++;
  		}
  		ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
  		ace->flag = eflag;
  		ace->access_mask = mask_from_posix(pa->e_perm & pas.mask,
  						   flags);
  		ace->whotype = NFS4_ACL_WHO_NAMED;
  		ace->who = pa->e_id;
  		ace++;
  		acl->naces++;

  		pa++;
  	}
  
  	/* In the case of groups, we apply allow ACEs first, then deny ACEs,
  	 * since a user can be in more than one group.  */
  
  	/* allow ACEs */

  	group_owner_entry = pa;

  
  	ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
  	ace->flag = eflag;
  	ace->access_mask = mask_from_posix(pas.group, flags);
  	ace->whotype = NFS4_ACL_WHO_GROUP;
  	ace++;
  	acl->naces++;

  	pa++;
  
  	while (pa->e_tag == ACL_GROUP) {

  		ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
  		ace->flag = eflag | NFS4_ACE_IDENTIFIER_GROUP;
  		ace->access_mask = mask_from_posix(pa->e_perm & pas.mask,
  						   flags);
  		ace->whotype = NFS4_ACL_WHO_NAMED;
  		ace->who = pa->e_id;
  		ace++;
  		acl->naces++;

  		pa++;
  	}
  
  	/* deny ACEs */
  
  	pa = group_owner_entry;

  
  	deny = ~pas.group & pas.other;
  	if (deny) {
  		ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;

  		ace->flag = eflag;

  		ace->access_mask = deny_mask_from_posix(deny, flags);
  		ace->whotype = NFS4_ACL_WHO_GROUP;
  		ace++;
  		acl->naces++;
  	}

  	pa++;

  	while (pa->e_tag == ACL_GROUP) {

  		deny = ~(pa->e_perm & pas.mask);
  		deny &= pas.other;
  		if (deny) {
  			ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
  			ace->flag = eflag | NFS4_ACE_IDENTIFIER_GROUP;

  			ace->access_mask = deny_mask_from_posix(deny, flags);

  			ace->whotype = NFS4_ACL_WHO_NAMED;
  			ace->who = pa->e_id;
  			ace++;
  			acl->naces++;
  		}

  		pa++;
  	}
  
  	if (pa->e_tag == ACL_MASK)
  		pa++;

  	ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
  	ace->flag = eflag;
  	ace->access_mask = mask_from_posix(pa->e_perm, flags);
  	ace->whotype = NFS4_ACL_WHO_EVERYONE;
  	acl->naces++;

  }
  
  static void
  sort_pacl_range(struct posix_acl *pacl, int start, int end) {
  	int sorted = 0, i;
  	struct posix_acl_entry tmp;
  
  	/* We just do a bubble sort; easy to do in place, and we're not
  	 * expecting acl's to be long enough to justify anything more. */
  	while (!sorted) {
  		sorted = 1;
  		for (i = start; i < end; i++) {
  			if (pacl->a_entries[i].e_id
  					> pacl->a_entries[i+1].e_id) {
  				sorted = 0;
  				tmp = pacl->a_entries[i];
  				pacl->a_entries[i] = pacl->a_entries[i+1];
  				pacl->a_entries[i+1] = tmp;
  			}
  		}
  	}
  }
  
  static void
  sort_pacl(struct posix_acl *pacl)
  {
  	/* posix_acl_valid requires that users and groups be in order
  	 * by uid/gid. */
  	int i, j;
  
  	if (pacl->a_count <= 4)
  		return; /* no users or groups */
  	i = 1;
  	while (pacl->a_entries[i].e_tag == ACL_USER)
  		i++;
  	sort_pacl_range(pacl, 1, i-1);
  
  	BUG_ON(pacl->a_entries[i].e_tag != ACL_GROUP_OBJ);

  	j = ++i;

  	while (pacl->a_entries[j].e_tag == ACL_GROUP)
  		j++;
  	sort_pacl_range(pacl, i, j-1);
  	return;
  }

  /*
   * While processing the NFSv4 ACE, this maintains bitmasks representing
   * which permission bits have been allowed and which denied to a given
   * entity: */
  struct posix_ace_state {
  	u32 allow;
  	u32 deny;
  };
  
  struct posix_user_ace_state {
  	uid_t uid;
  	struct posix_ace_state perms;
  };
  
  struct posix_ace_state_array {
  	int n;
  	struct posix_user_ace_state aces[];
  };
  
  /*
   * While processing the NFSv4 ACE, this maintains the partial permissions
   * calculated so far: */
  
  struct posix_acl_state {

  	int empty;

  	struct posix_ace_state owner;
  	struct posix_ace_state group;
  	struct posix_ace_state other;
  	struct posix_ace_state everyone;
  	struct posix_ace_state mask; /* Deny unused in this case */
  	struct posix_ace_state_array *users;
  	struct posix_ace_state_array *groups;
  };

  static int

  init_state(struct posix_acl_state *state, int cnt)

  {

  	int alloc;
  
  	memset(state, 0, sizeof(struct posix_acl_state));

  	state->empty = 1;

  	/*
  	 * In the worst case, each individual acl could be for a distinct
  	 * named user or group, but we don't no which, so we allocate
  	 * enough space for either:
  	 */
  	alloc = sizeof(struct posix_ace_state_array)

  		+ cnt*sizeof(struct posix_user_ace_state);

  	state->users = kzalloc(alloc, GFP_KERNEL);
  	if (!state->users)
  		return -ENOMEM;
  	state->groups = kzalloc(alloc, GFP_KERNEL);
  	if (!state->groups) {
  		kfree(state->users);
  		return -ENOMEM;
  	}
  	return 0;

  }

  static void
  free_state(struct posix_acl_state *state) {
  	kfree(state->users);
  	kfree(state->groups);

  }

  static inline void add_to_mask(struct posix_acl_state *state, struct posix_ace_state *astate)

  {

  	state->mask.allow |= astate->allow;

  }

  /*
   * Certain bits (SYNCHRONIZE, DELETE, WRITE_OWNER, READ/WRITE_NAMED_ATTRS,
   * READ_ATTRIBUTES, READ_ACL) are currently unenforceable and don't translate
   * to traditional read/write/execute permissions.
   *
   * It's problematic to reject acls that use certain mode bits, because it
   * places the burden on users to learn the rules about which bits one
   * particular server sets, without giving the user a lot of help--we return an
   * error that could mean any number of different things.  To make matters
   * worse, the problematic bits might be introduced by some application that's
   * automatically mapping from some other acl model.
   *
   * So wherever possible we accept anything, possibly erring on the side of
   * denying more permissions than necessary.
   *
   * However we do reject *explicit* DENY's of a few bits representing
   * permissions we could never deny:
   */

  static inline int check_deny(u32 mask, int isowner)
  {
  	if (mask & (NFS4_ACE_READ_ATTRIBUTES | NFS4_ACE_READ_ACL))
  		return -EINVAL;
  	if (!isowner)
  		return 0;
  	if (mask & (NFS4_ACE_WRITE_ATTRIBUTES | NFS4_ACE_WRITE_ACL))
  		return -EINVAL;
  	return 0;

  }

  static struct posix_acl *
  posix_state_to_acl(struct posix_acl_state *state, unsigned int flags)

  {

  	struct posix_acl_entry *pace;
  	struct posix_acl *pacl;
  	int nace;
  	int i, error = 0;

  	/*
  	 * ACLs with no ACEs are treated differently in the inheritable
  	 * and effective cases: when there are no inheritable ACEs, we
  	 * set a zero-length default posix acl:
  	 */
  	if (state->empty && (flags & NFS4_ACL_TYPE_DEFAULT)) {
  		pacl = posix_acl_alloc(0, GFP_KERNEL);
  		return pacl ? pacl : ERR_PTR(-ENOMEM);
  	}
  	/*
  	 * When there are no effective ACEs, the following will end
  	 * up setting a 3-element effective posix ACL with all
  	 * permissions zero.
  	 */

  	nace = 4 + state->users->n + state->groups->n;
  	pacl = posix_acl_alloc(nace, GFP_KERNEL);
  	if (!pacl)
  		return ERR_PTR(-ENOMEM);

  	pace = pacl->a_entries;
  	pace->e_tag = ACL_USER_OBJ;
  	error = check_deny(state->owner.deny, 1);
  	if (error)
  		goto out_err;
  	low_mode_from_nfs4(state->owner.allow, &pace->e_perm, flags);
  	pace->e_id = ACL_UNDEFINED_ID;
  
  	for (i=0; i < state->users->n; i++) {
  		pace++;
  		pace->e_tag = ACL_USER;
  		error = check_deny(state->users->aces[i].perms.deny, 0);
  		if (error)
  			goto out_err;
  		low_mode_from_nfs4(state->users->aces[i].perms.allow,
  					&pace->e_perm, flags);
  		pace->e_id = state->users->aces[i].uid;
  		add_to_mask(state, &state->users->aces[i].perms);

  	}

  	pace++;
  	pace->e_tag = ACL_GROUP_OBJ;
  	error = check_deny(state->group.deny, 0);
  	if (error)
  		goto out_err;
  	low_mode_from_nfs4(state->group.allow, &pace->e_perm, flags);
  	pace->e_id = ACL_UNDEFINED_ID;
  	add_to_mask(state, &state->group);
  
  	for (i=0; i < state->groups->n; i++) {
  		pace++;
  		pace->e_tag = ACL_GROUP;
  		error = check_deny(state->groups->aces[i].perms.deny, 0);
  		if (error)
  			goto out_err;
  		low_mode_from_nfs4(state->groups->aces[i].perms.allow,
  					&pace->e_perm, flags);
  		pace->e_id = state->groups->aces[i].uid;
  		add_to_mask(state, &state->groups->aces[i].perms);
  	}

  	pace++;
  	pace->e_tag = ACL_MASK;
  	low_mode_from_nfs4(state->mask.allow, &pace->e_perm, flags);
  	pace->e_id = ACL_UNDEFINED_ID;

  	pace++;
  	pace->e_tag = ACL_OTHER;
  	error = check_deny(state->other.deny, 0);
  	if (error)
  		goto out_err;
  	low_mode_from_nfs4(state->other.allow, &pace->e_perm, flags);
  	pace->e_id = ACL_UNDEFINED_ID;

  	return pacl;
  out_err:
  	posix_acl_release(pacl);
  	return ERR_PTR(error);
  }

  static inline void allow_bits(struct posix_ace_state *astate, u32 mask)
  {
  	/* Allow all bits in the mask not already denied: */
  	astate->allow |= mask & ~astate->deny;
  }

  static inline void deny_bits(struct posix_ace_state *astate, u32 mask)
  {
  	/* Deny all bits in the mask not already allowed: */
  	astate->deny |= mask & ~astate->allow;
  }

  static int find_uid(struct posix_acl_state *state, struct posix_ace_state_array *a, uid_t uid)
  {
  	int i;

  	for (i = 0; i < a->n; i++)
  		if (a->aces[i].uid == uid)
  			return i;
  	/* Not found: */
  	a->n++;
  	a->aces[i].uid = uid;
  	a->aces[i].perms.allow = state->everyone.allow;
  	a->aces[i].perms.deny  = state->everyone.deny;

  	return i;

  }

  static void deny_bits_array(struct posix_ace_state_array *a, u32 mask)

  {

  	int i;

  	for (i=0; i < a->n; i++)
  		deny_bits(&a->aces[i].perms, mask);

  }

  static void allow_bits_array(struct posix_ace_state_array *a, u32 mask)

  {

  	int i;

  	for (i=0; i < a->n; i++)
  		allow_bits(&a->aces[i].perms, mask);

  }

  static void process_one_v4_ace(struct posix_acl_state *state,
  				struct nfs4_ace *ace)

  {

  	u32 mask = ace->access_mask;
  	int i;

  	state->empty = 0;

  	switch (ace2type(ace)) {
  	case ACL_USER_OBJ:
  		if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
  			allow_bits(&state->owner, mask);
  		} else {
  			deny_bits(&state->owner, mask);
  		}
  		break;
  	case ACL_USER:
  		i = find_uid(state, state->users, ace->who);
  		if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
  			allow_bits(&state->users->aces[i].perms, mask);
  		} else {
  			deny_bits(&state->users->aces[i].perms, mask);
  			mask = state->users->aces[i].perms.deny;
  			deny_bits(&state->owner, mask);
  		}
  		break;
  	case ACL_GROUP_OBJ:
  		if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
  			allow_bits(&state->group, mask);
  		} else {
  			deny_bits(&state->group, mask);
  			mask = state->group.deny;
  			deny_bits(&state->owner, mask);
  			deny_bits(&state->everyone, mask);
  			deny_bits_array(state->users, mask);
  			deny_bits_array(state->groups, mask);
  		}
  		break;
  	case ACL_GROUP:
  		i = find_uid(state, state->groups, ace->who);
  		if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
  			allow_bits(&state->groups->aces[i].perms, mask);
  		} else {
  			deny_bits(&state->groups->aces[i].perms, mask);
  			mask = state->groups->aces[i].perms.deny;
  			deny_bits(&state->owner, mask);
  			deny_bits(&state->group, mask);
  			deny_bits(&state->everyone, mask);
  			deny_bits_array(state->users, mask);
  			deny_bits_array(state->groups, mask);
  		}
  		break;
  	case ACL_OTHER:
  		if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
  			allow_bits(&state->owner, mask);
  			allow_bits(&state->group, mask);
  			allow_bits(&state->other, mask);
  			allow_bits(&state->everyone, mask);
  			allow_bits_array(state->users, mask);
  			allow_bits_array(state->groups, mask);
  		} else {
  			deny_bits(&state->owner, mask);
  			deny_bits(&state->group, mask);
  			deny_bits(&state->other, mask);
  			deny_bits(&state->everyone, mask);
  			deny_bits_array(state->users, mask);
  			deny_bits_array(state->groups, mask);
  		}

  	}
  }

  int nfs4_acl_nfsv4_to_posix(struct nfs4_acl *acl, struct posix_acl **pacl,
  			    struct posix_acl **dpacl, unsigned int flags)

  {

  	struct posix_acl_state effective_acl_state, default_acl_state;

  	struct nfs4_ace *ace;
  	int ret;

  	ret = init_state(&effective_acl_state, acl->naces);

  	if (ret)

  		return ret;
  	ret = init_state(&default_acl_state, acl->naces);
  	if (ret)
  		goto out_estate;
  	ret = -EINVAL;

  	for (ace = acl->aces; ace < acl->aces + acl->naces; ace++) {

  		if (ace->type != NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE &&
  		    ace->type != NFS4_ACE_ACCESS_DENIED_ACE_TYPE)

  			goto out_dstate;

  		if (ace->flag & ~NFS4_SUPPORTED_FLAGS)

  			goto out_dstate;

  		if ((ace->flag & NFS4_INHERITANCE_FLAGS) == 0) {

  			process_one_v4_ace(&effective_acl_state, ace);

  			continue;

  		}

  		if (!(flags & NFS4_ACL_DIR))
  			goto out_dstate;

  		/*
  		 * Note that when only one of FILE_INHERIT or DIRECTORY_INHERIT
  		 * is set, we're effectively turning on the other.  That's OK,
  		 * according to rfc 3530.
  		 */

  		process_one_v4_ace(&default_acl_state, ace);
  
  		if (!(ace->flag & NFS4_ACE_INHERIT_ONLY_ACE))
  			process_one_v4_ace(&effective_acl_state, ace);

  	}

  	*pacl = posix_state_to_acl(&effective_acl_state, flags);
  	if (IS_ERR(*pacl)) {
  		ret = PTR_ERR(*pacl);

  		*pacl = NULL;

  		goto out_dstate;
  	}

  	*dpacl = posix_state_to_acl(&default_acl_state,
  						flags | NFS4_ACL_TYPE_DEFAULT);

  	if (IS_ERR(*dpacl)) {
  		ret = PTR_ERR(*dpacl);

  		*dpacl = NULL;

  		posix_acl_release(*pacl);

  		*pacl = NULL;

  		goto out_dstate;
  	}
  	sort_pacl(*pacl);
  	sort_pacl(*dpacl);
  	ret = 0;
  out_dstate:
  	free_state(&default_acl_state);
  out_estate:
  	free_state(&effective_acl_state);
  	return ret;

  }
  
  static short
  ace2type(struct nfs4_ace *ace)
  {
  	switch (ace->whotype) {
  		case NFS4_ACL_WHO_NAMED:
  			return (ace->flag & NFS4_ACE_IDENTIFIER_GROUP ?
  					ACL_GROUP : ACL_USER);
  		case NFS4_ACL_WHO_OWNER:
  			return ACL_USER_OBJ;
  		case NFS4_ACL_WHO_GROUP:
  			return ACL_GROUP_OBJ;
  		case NFS4_ACL_WHO_EVERYONE:
  			return ACL_OTHER;
  	}
  	BUG();
  	return -1;
  }
  
  EXPORT_SYMBOL(nfs4_acl_posix_to_nfsv4);
  EXPORT_SYMBOL(nfs4_acl_nfsv4_to_posix);
  
  struct nfs4_acl *

  nfs4_acl_new(int n)

  {
  	struct nfs4_acl *acl;

  	acl = kmalloc(sizeof(*acl) + n*sizeof(struct nfs4_ace), GFP_KERNEL);
  	if (acl == NULL)

  		return NULL;

  	acl->naces = 0;

  	return acl;
  }

  static struct {
  	char *string;
  	int   stringlen;
  	int type;
  } s2t_map[] = {
  	{
  		.string    = "OWNER@",
  		.stringlen = sizeof("OWNER@") - 1,
  		.type      = NFS4_ACL_WHO_OWNER,
  	},
  	{
  		.string    = "GROUP@",
  		.stringlen = sizeof("GROUP@") - 1,
  		.type      = NFS4_ACL_WHO_GROUP,
  	},
  	{
  		.string    = "EVERYONE@",
  		.stringlen = sizeof("EVERYONE@") - 1,
  		.type      = NFS4_ACL_WHO_EVERYONE,
  	},
  };
  
  int
  nfs4_acl_get_whotype(char *p, u32 len)
  {
  	int i;

  	for (i = 0; i < ARRAY_SIZE(s2t_map); i++) {

  		if (s2t_map[i].stringlen == len &&
  				0 == memcmp(s2t_map[i].string, p, len))
  			return s2t_map[i].type;
  	}
  	return NFS4_ACL_WHO_NAMED;
  }
  
  int
  nfs4_acl_write_who(int who, char *p)
  {
  	int i;

  	for (i = 0; i < ARRAY_SIZE(s2t_map); i++) {

  		if (s2t_map[i].type == who) {
  			memcpy(p, s2t_map[i].string, s2t_map[i].stringlen);
  			return s2t_map[i].stringlen;
  		}
  	}
  	BUG();
  	return -1;
  }

  EXPORT_SYMBOL(nfs4_acl_new);

  EXPORT_SYMBOL(nfs4_acl_get_whotype);
  EXPORT_SYMBOL(nfs4_acl_write_who);