Initial import of modified Linux 2.6.28 tree

Original upstream URL:
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git | branch linux-2.6.28.y

1 files changed, 874 insertions, 0 deletions

diff --git a/fs/xfs/xfs_acl.c b/fs/xfs/xfs_acl.c
new file mode 100644
index 0000000..b2f639a
--- /dev/null
+++ b/fs/xfs/xfs_acl.c
@@ -0,0 +1,874 @@
+/*
+ * Copyright (c) 2001-2002,2005 Silicon Graphics, Inc.
+ * All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_types.h"
+#include "xfs_bit.h"
+#include "xfs_inum.h"
+#include "xfs_ag.h"
+#include "xfs_dir2.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_alloc_btree.h"
+#include "xfs_ialloc_btree.h"
+#include "xfs_dir2_sf.h"
+#include "xfs_attr_sf.h"
+#include "xfs_dinode.h"
+#include "xfs_inode.h"
+#include "xfs_btree.h"
+#include "xfs_acl.h"
+#include "xfs_attr.h"
+#include "xfs_vnodeops.h"
+
+#include <linux/capability.h>
+#include <linux/posix_acl_xattr.h>
+
+STATIC int	xfs_acl_setmode(struct inode *, xfs_acl_t *, int *);
+STATIC void     xfs_acl_filter_mode(mode_t, xfs_acl_t *);
+STATIC void	xfs_acl_get_endian(xfs_acl_t *);
+STATIC int	xfs_acl_access(uid_t, gid_t, xfs_acl_t *, mode_t, cred_t *);
+STATIC int	xfs_acl_invalid(xfs_acl_t *);
+STATIC void	xfs_acl_sync_mode(mode_t, xfs_acl_t *);
+STATIC void	xfs_acl_get_attr(struct inode *, xfs_acl_t *, int, int, int *);
+STATIC void	xfs_acl_set_attr(struct inode *, xfs_acl_t *, int, int *);
+STATIC int	xfs_acl_allow_set(struct inode *, int);
+
+kmem_zone_t *xfs_acl_zone;
+
+
+/*
+ * Test for existence of access ACL attribute as efficiently as possible.
+ */
+int
+xfs_acl_vhasacl_access(
+	struct inode	*vp)
+{
+	int		error;
+
+	xfs_acl_get_attr(vp, NULL, _ACL_TYPE_ACCESS, ATTR_KERNOVAL, &error);
+	return (error == 0);
+}
+
+/*
+ * Test for existence of default ACL attribute as efficiently as possible.
+ */
+int
+xfs_acl_vhasacl_default(
+	struct inode	*vp)
+{
+	int		error;
+
+	if (!S_ISDIR(vp->i_mode))
+		return 0;
+	xfs_acl_get_attr(vp, NULL, _ACL_TYPE_DEFAULT, ATTR_KERNOVAL, &error);
+	return (error == 0);
+}
+
+/*
+ * Convert from extended attribute representation to in-memory for XFS.
+ */
+STATIC int
+posix_acl_xattr_to_xfs(
+	posix_acl_xattr_header	*src,
+	size_t			size,
+	xfs_acl_t		*dest)
+{
+	posix_acl_xattr_entry	*src_entry;
+	xfs_acl_entry_t		*dest_entry;
+	int			n;
+
+	if (!src || !dest)
+		return EINVAL;
+
+	if (size < sizeof(posix_acl_xattr_header))
+		return EINVAL;
+
+	if (src->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
+		return EOPNOTSUPP;
+
+	memset(dest, 0, sizeof(xfs_acl_t));
+	dest->acl_cnt = posix_acl_xattr_count(size);
+	if (dest->acl_cnt < 0 || dest->acl_cnt > XFS_ACL_MAX_ENTRIES)
+		return EINVAL;
+
+	/*
+	 * acl_set_file(3) may request that we set default ACLs with
+	 * zero length -- defend (gracefully) against that here.
+	 */
+	if (!dest->acl_cnt)
+		return 0;
+
+	src_entry = (posix_acl_xattr_entry *)((char *)src + sizeof(*src));
+	dest_entry = &dest->acl_entry[0];
+
+	for (n = 0; n < dest->acl_cnt; n++, src_entry++, dest_entry++) {
+		dest_entry->ae_perm = le16_to_cpu(src_entry->e_perm);
+		if (_ACL_PERM_INVALID(dest_entry->ae_perm))
+			return EINVAL;
+		dest_entry->ae_tag  = le16_to_cpu(src_entry->e_tag);
+		switch(dest_entry->ae_tag) {
+		case ACL_USER:
+		case ACL_GROUP:
+			dest_entry->ae_id = le32_to_cpu(src_entry->e_id);
+			break;
+		case ACL_USER_OBJ:
+		case ACL_GROUP_OBJ:
+		case ACL_MASK:
+		case ACL_OTHER:
+			dest_entry->ae_id = ACL_UNDEFINED_ID;
+			break;
+		default:
+			return EINVAL;
+		}
+	}
+	if (xfs_acl_invalid(dest))
+		return EINVAL;
+
+	return 0;
+}
+
+/*
+ * Comparison function called from xfs_sort().
+ * Primary key is ae_tag, secondary key is ae_id.
+ */
+STATIC int
+xfs_acl_entry_compare(
+	const void	*va,
+	const void	*vb)
+{
+	xfs_acl_entry_t	*a = (xfs_acl_entry_t *)va,
+			*b = (xfs_acl_entry_t *)vb;
+
+	if (a->ae_tag == b->ae_tag)
+		return (a->ae_id - b->ae_id);
+	return (a->ae_tag - b->ae_tag);
+}
+
+/*
+ * Convert from in-memory XFS to extended attribute representation.
+ */
+STATIC int
+posix_acl_xfs_to_xattr(
+	xfs_acl_t		*src,
+	posix_acl_xattr_header	*dest,
+	size_t			size)
+{
+	int			n;
+	size_t			new_size = posix_acl_xattr_size(src->acl_cnt);
+	posix_acl_xattr_entry	*dest_entry;
+	xfs_acl_entry_t		*src_entry;
+
+	if (size < new_size)
+		return -ERANGE;
+
+	/* Need to sort src XFS ACL by <ae_tag,ae_id> */
+	xfs_sort(src->acl_entry, src->acl_cnt, sizeof(src->acl_entry[0]),
+		 xfs_acl_entry_compare);
+
+	dest->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);
+	dest_entry = &dest->a_entries[0];
+	src_entry = &src->acl_entry[0];
+	for (n = 0; n < src->acl_cnt; n++, dest_entry++, src_entry++) {
+		dest_entry->e_perm = cpu_to_le16(src_entry->ae_perm);
+		if (_ACL_PERM_INVALID(src_entry->ae_perm))
+			return -EINVAL;
+		dest_entry->e_tag  = cpu_to_le16(src_entry->ae_tag);
+		switch (src_entry->ae_tag) {
+		case ACL_USER:
+		case ACL_GROUP:
+			dest_entry->e_id = cpu_to_le32(src_entry->ae_id);
+				break;
+		case ACL_USER_OBJ:
+		case ACL_GROUP_OBJ:
+		case ACL_MASK:
+		case ACL_OTHER:
+			dest_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID);
+			break;
+		default:
+			return -EINVAL;
+		}
+	}
+	return new_size;
+}
+
+int
+xfs_acl_vget(
+	struct inode	*vp,
+	void		*acl,
+	size_t		size,
+	int		kind)
+{
+	int			error;
+	xfs_acl_t		*xfs_acl = NULL;
+	posix_acl_xattr_header	*ext_acl = acl;
+	int			flags = 0;
+
+	if(size) {
+		if (!(_ACL_ALLOC(xfs_acl))) {
+			error = ENOMEM;
+			goto out;
+		}
+		memset(xfs_acl, 0, sizeof(xfs_acl_t));
+	} else
+		flags = ATTR_KERNOVAL;
+
+	xfs_acl_get_attr(vp, xfs_acl, kind, flags, &error);
+	if (error)
+		goto out;
+
+	if (!size) {
+		error = -posix_acl_xattr_size(XFS_ACL_MAX_ENTRIES);
+	} else {
+		if (xfs_acl_invalid(xfs_acl)) {
+			error = EINVAL;
+			goto out;
+		}
+		if (kind == _ACL_TYPE_ACCESS)
+			xfs_acl_sync_mode(XFS_I(vp)->i_d.di_mode, xfs_acl);
+		error = -posix_acl_xfs_to_xattr(xfs_acl, ext_acl, size);
+	}
+out:
+	if(xfs_acl)
+		_ACL_FREE(xfs_acl);
+	return -error;
+}
+
+int
+xfs_acl_vremove(
+	struct inode	*vp,
+	int		kind)
+{
+	int		error;
+
+	error = xfs_acl_allow_set(vp, kind);
+	if (!error) {
+		error = xfs_attr_remove(XFS_I(vp),
+						kind == _ACL_TYPE_DEFAULT?
+						SGI_ACL_DEFAULT: SGI_ACL_FILE,
+						ATTR_ROOT);
+		if (error == ENOATTR)
+			error = 0;	/* 'scool */
+	}
+	return -error;
+}
+
+int
+xfs_acl_vset(
+	struct inode		*vp,
+	void			*acl,
+	size_t			size,
+	int			kind)
+{
+	posix_acl_xattr_header	*ext_acl = acl;
+	xfs_acl_t		*xfs_acl;
+	int			error;
+	int			basicperms = 0; /* more than std unix perms? */
+
+	if (!acl)
+		return -EINVAL;
+
+	if (!(_ACL_ALLOC(xfs_acl)))
+		return -ENOMEM;
+
+	error = posix_acl_xattr_to_xfs(ext_acl, size, xfs_acl);
+	if (error) {
+		_ACL_FREE(xfs_acl);
+		return -error;
+	}
+	if (!xfs_acl->acl_cnt) {
+		_ACL_FREE(xfs_acl);
+		return 0;
+	}
+
+	error = xfs_acl_allow_set(vp, kind);
+
+	/* Incoming ACL exists, set file mode based on its value */
+	if (!error && kind == _ACL_TYPE_ACCESS)
+		error = xfs_acl_setmode(vp, xfs_acl, &basicperms);
+
+	if (error)
+		goto out;
+
+	/*
+	 * If we have more than std unix permissions, set up the actual attr.
+	 * Otherwise, delete any existing attr.  This prevents us from
+	 * having actual attrs for permissions that can be stored in the
+	 * standard permission bits.
+	 */
+	if (!basicperms) {
+		xfs_acl_set_attr(vp, xfs_acl, kind, &error);
+	} else {
+		error = -xfs_acl_vremove(vp, _ACL_TYPE_ACCESS);
+	}
+
+out:
+	_ACL_FREE(xfs_acl);
+	return -error;
+}
+
+int
+xfs_acl_iaccess(
+	xfs_inode_t	*ip,
+	mode_t		mode,
+	cred_t		*cr)
+{
+	xfs_acl_t	*acl;
+	int		rval;
+	struct xfs_name	acl_name = {SGI_ACL_FILE, SGI_ACL_FILE_SIZE};
+
+	if (!(_ACL_ALLOC(acl)))
+		return -1;
+
+	/* If the file has no ACL return -1. */
+	rval = sizeof(xfs_acl_t);
+	if (xfs_attr_fetch(ip, &acl_name, (char *)acl, &rval, ATTR_ROOT)) {
+		_ACL_FREE(acl);
+		return -1;
+	}
+	xfs_acl_get_endian(acl);
+
+	/* If the file has an empty ACL return -1. */
+	if (acl->acl_cnt == XFS_ACL_NOT_PRESENT) {
+		_ACL_FREE(acl);
+		return -1;
+	}
+
+	/* Synchronize ACL with mode bits */
+	xfs_acl_sync_mode(ip->i_d.di_mode, acl);
+
+	rval = xfs_acl_access(ip->i_d.di_uid, ip->i_d.di_gid, acl, mode, cr);
+	_ACL_FREE(acl);
+	return rval;
+}
+
+STATIC int
+xfs_acl_allow_set(
+	struct inode	*vp,
+	int		kind)
+{
+	if (vp->i_flags & (S_IMMUTABLE|S_APPEND))
+		return EPERM;
+	if (kind == _ACL_TYPE_DEFAULT && !S_ISDIR(vp->i_mode))
+		return ENOTDIR;
+	if (vp->i_sb->s_flags & MS_RDONLY)
+		return EROFS;
+	if (XFS_I(vp)->i_d.di_uid != current->fsuid && !capable(CAP_FOWNER))
+		return EPERM;
+	return 0;
+}
+
+/*
+ * Note: cr is only used here for the capability check if the ACL test fails.
+ *       It is not used to find out the credentials uid or groups etc, as was
+ *       done in IRIX. It is assumed that the uid and groups for the current
+ *       thread are taken from "current" instead of the cr parameter.
+ */
+STATIC int
+xfs_acl_access(
+	uid_t		fuid,
+	gid_t		fgid,
+	xfs_acl_t	*fap,
+	mode_t		md,
+	cred_t		*cr)
+{
+	xfs_acl_entry_t	matched;
+	int		i, allows;
+	int		maskallows = -1;	/* true, but not 1, either */
+	int		seen_userobj = 0;
+
+	matched.ae_tag = 0;	/* Invalid type */
+	matched.ae_perm = 0;
+
+	for (i = 0; i < fap->acl_cnt; i++) {
+		/*
+		 * Break out if we've got a user_obj entry or
+		 * a user entry and the mask (and have processed USER_OBJ)
+		 */
+		if (matched.ae_tag == ACL_USER_OBJ)
+			break;
+		if (matched.ae_tag == ACL_USER) {
+			if (maskallows != -1 && seen_userobj)
+				break;
+			if (fap->acl_entry[i].ae_tag != ACL_MASK &&
+			    fap->acl_entry[i].ae_tag != ACL_USER_OBJ)
+				continue;
+		}
+		/* True if this entry allows the requested access */
+		allows = ((fap->acl_entry[i].ae_perm & md) == md);
+
+		switch (fap->acl_entry[i].ae_tag) {
+		case ACL_USER_OBJ:
+			seen_userobj = 1;
+			if (fuid != current->fsuid)
+				continue;
+			matched.ae_tag = ACL_USER_OBJ;
+			matched.ae_perm = allows;
+			break;
+		case ACL_USER:
+			if (fap->acl_entry[i].ae_id != current->fsuid)
+				continue;
+			matched.ae_tag = ACL_USER;
+			matched.ae_perm = allows;
+			break;
+		case ACL_GROUP_OBJ:
+			if ((matched.ae_tag == ACL_GROUP_OBJ ||
+			    matched.ae_tag == ACL_GROUP) && !allows)
+				continue;
+			if (!in_group_p(fgid))
+				continue;
+			matched.ae_tag = ACL_GROUP_OBJ;
+			matched.ae_perm = allows;
+			break;
+		case ACL_GROUP:
+			if ((matched.ae_tag == ACL_GROUP_OBJ ||
+			    matched.ae_tag == ACL_GROUP) && !allows)
+				continue;
+			if (!in_group_p(fap->acl_entry[i].ae_id))
+				continue;
+			matched.ae_tag = ACL_GROUP;
+			matched.ae_perm = allows;
+			break;
+		case ACL_MASK:
+			maskallows = allows;
+			break;
+		case ACL_OTHER:
+			if (matched.ae_tag != 0)
+				continue;
+			matched.ae_tag = ACL_OTHER;
+			matched.ae_perm = allows;
+			break;
+		}
+	}
+	/*
+	 * First possibility is that no matched entry allows access.
+	 * The capability to override DAC may exist, so check for it.
+	 */
+	switch (matched.ae_tag) {
+	case ACL_OTHER:
+	case ACL_USER_OBJ:
+		if (matched.ae_perm)
+			return 0;
+		break;
+	case ACL_USER:
+	case ACL_GROUP_OBJ:
+	case ACL_GROUP:
+		if (maskallows && matched.ae_perm)
+			return 0;
+		break;
+	case 0:
+		break;
+	}
+
+	/* EACCES tells generic_permission to check for capability overrides */
+	return EACCES;
+}
+
+/*
+ * ACL validity checker.
+ *   This acl validation routine checks each ACL entry read in makes sense.
+ */
+STATIC int
+xfs_acl_invalid(
+	xfs_acl_t	*aclp)
+{
+	xfs_acl_entry_t	*entry, *e;
+	int		user = 0, group = 0, other = 0, mask = 0;
+	int		mask_required = 0;
+	int		i, j;
+
+	if (!aclp)
+		goto acl_invalid;
+
+	if (aclp->acl_cnt > XFS_ACL_MAX_ENTRIES)
+		goto acl_invalid;
+
+	for (i = 0; i < aclp->acl_cnt; i++) {
+		entry = &aclp->acl_entry[i];
+		switch (entry->ae_tag) {
+		case ACL_USER_OBJ:
+			if (user++)
+				goto acl_invalid;
+			break;
+		case ACL_GROUP_OBJ:
+			if (group++)
+				goto acl_invalid;
+			break;
+		case ACL_OTHER:
+			if (other++)
+				goto acl_invalid;
+			break;
+		case ACL_USER:
+		case ACL_GROUP:
+			for (j = i + 1; j < aclp->acl_cnt; j++) {
+				e = &aclp->acl_entry[j];
+				if (e->ae_id == entry->ae_id &&
+				    e->ae_tag == entry->ae_tag)
+					goto acl_invalid;
+			}
+			mask_required++;
+			break;
+		case ACL_MASK:
+			if (mask++)
+				goto acl_invalid;
+			break;
+		default:
+			goto acl_invalid;
+		}
+	}
+	if (!user || !group || !other || (mask_required && !mask))
+		goto acl_invalid;
+	else
+		return 0;
+acl_invalid:
+	return EINVAL;
+}
+
+/*
+ * Do ACL endian conversion.
+ */
+STATIC void
+xfs_acl_get_endian(
+	xfs_acl_t	*aclp)
+{
+	xfs_acl_entry_t	*ace, *end;
+
+	INT_SET(aclp->acl_cnt, ARCH_CONVERT, aclp->acl_cnt);
+	end = &aclp->acl_entry[0]+aclp->acl_cnt;
+	for (ace = &aclp->acl_entry[0]; ace < end; ace++) {
+		INT_SET(ace->ae_tag, ARCH_CONVERT, ace->ae_tag);
+		INT_SET(ace->ae_id, ARCH_CONVERT, ace->ae_id);
+		INT_SET(ace->ae_perm, ARCH_CONVERT, ace->ae_perm);
+	}
+}
+
+/*
+ * Get the ACL from the EA and do endian conversion.
+ */
+STATIC void
+xfs_acl_get_attr(
+	struct inode	*vp,
+	xfs_acl_t	*aclp,
+	int		kind,
+	int		flags,
+	int		*error)
+{
+	int		len = sizeof(xfs_acl_t);
+
+	ASSERT((flags & ATTR_KERNOVAL) ? (aclp == NULL) : 1);
+	flags |= ATTR_ROOT;
+	*error = xfs_attr_get(XFS_I(vp),
+					kind == _ACL_TYPE_ACCESS ?
+					SGI_ACL_FILE : SGI_ACL_DEFAULT,
+					(char *)aclp, &len, flags);
+	if (*error || (flags & ATTR_KERNOVAL))
+		return;
+	xfs_acl_get_endian(aclp);
+}
+
+/*
+ * Set the EA with the ACL and do endian conversion.
+ */
+STATIC void
+xfs_acl_set_attr(
+	struct inode	*vp,
+	xfs_acl_t	*aclp,
+	int		kind,
+	int		*error)
+{
+	xfs_acl_entry_t	*ace, *newace, *end;
+	xfs_acl_t	*newacl;
+	int		len;
+
+	if (!(_ACL_ALLOC(newacl))) {
+		*error = ENOMEM;
+		return;
+	}
+
+	len = sizeof(xfs_acl_t) -
+	      (sizeof(xfs_acl_entry_t) * (XFS_ACL_MAX_ENTRIES - aclp->acl_cnt));
+	end = &aclp->acl_entry[0]+aclp->acl_cnt;
+	for (ace = &aclp->acl_entry[0], newace = &newacl->acl_entry[0];
+	     ace < end;
+	     ace++, newace++) {
+		INT_SET(newace->ae_tag, ARCH_CONVERT, ace->ae_tag);
+		INT_SET(newace->ae_id, ARCH_CONVERT, ace->ae_id);
+		INT_SET(newace->ae_perm, ARCH_CONVERT, ace->ae_perm);
+	}
+	INT_SET(newacl->acl_cnt, ARCH_CONVERT, aclp->acl_cnt);
+	*error = xfs_attr_set(XFS_I(vp),
+				kind == _ACL_TYPE_ACCESS ?
+				SGI_ACL_FILE: SGI_ACL_DEFAULT,
+				(char *)newacl, len, ATTR_ROOT);
+	_ACL_FREE(newacl);
+}
+
+int
+xfs_acl_vtoacl(
+	struct inode	*vp,
+	xfs_acl_t	*access_acl,
+	xfs_acl_t	*default_acl)
+{
+	int		error = 0;
+
+	if (access_acl) {
+		/*
+		 * Get the Access ACL and the mode.  If either cannot
+		 * be obtained for some reason, invalidate the access ACL.
+		 */
+		xfs_acl_get_attr(vp, access_acl, _ACL_TYPE_ACCESS, 0, &error);
+		if (error)
+			access_acl->acl_cnt = XFS_ACL_NOT_PRESENT;
+		else /* We have a good ACL and the file mode, synchronize. */
+			xfs_acl_sync_mode(XFS_I(vp)->i_d.di_mode, access_acl);
+	}
+
+	if (default_acl) {
+		xfs_acl_get_attr(vp, default_acl, _ACL_TYPE_DEFAULT, 0, &error);
+		if (error)
+			default_acl->acl_cnt = XFS_ACL_NOT_PRESENT;
+	}
+	return error;
+}
+
+/*
+ * This function retrieves the parent directory's acl, processes it
+ * and lets the child inherit the acl(s) that it should.
+ */
+int
+xfs_acl_inherit(
+	struct inode	*vp,
+	mode_t		mode,
+	xfs_acl_t	*pdaclp)
+{
+	xfs_acl_t	*cacl;
+	int		error = 0;
+	int		basicperms = 0;
+
+	/*
+	 * If the parent does not have a default ACL, or it's an
+	 * invalid ACL, we're done.
+	 */
+	if (!vp)
+		return 0;
+	if (!pdaclp || xfs_acl_invalid(pdaclp))
+		return 0;
+
+	/*
+	 * Copy the default ACL of the containing directory to
+	 * the access ACL of the new file and use the mode that
+	 * was passed in to set up the correct initial values for
+	 * the u::,g::[m::], and o:: entries.  This is what makes
+	 * umask() "work" with ACL's.
+	 */
+
+	if (!(_ACL_ALLOC(cacl)))
+		return ENOMEM;
+
+	memcpy(cacl, pdaclp, sizeof(xfs_acl_t));
+	xfs_acl_filter_mode(mode, cacl);
+	error = xfs_acl_setmode(vp, cacl, &basicperms);
+	if (error)
+		goto out_error;
+
+	/*
+	 * Set the Default and Access ACL on the file.  The mode is already
+	 * set on the file, so we don't need to worry about that.
+	 *
+	 * If the new file is a directory, its default ACL is a copy of
+	 * the containing directory's default ACL.
+	 */
+	if (S_ISDIR(vp->i_mode))
+		xfs_acl_set_attr(vp, pdaclp, _ACL_TYPE_DEFAULT, &error);
+	if (!error && !basicperms)
+		xfs_acl_set_attr(vp, cacl, _ACL_TYPE_ACCESS, &error);
+out_error:
+	_ACL_FREE(cacl);
+	return error;
+}
+
+/*
+ * Set up the correct mode on the file based on the supplied ACL.  This
+ * makes sure that the mode on the file reflects the state of the
+ * u::,g::[m::], and o:: entries in the ACL.  Since the mode is where
+ * the ACL is going to get the permissions for these entries, we must
+ * synchronize the mode whenever we set the ACL on a file.
+ */
+STATIC int
+xfs_acl_setmode(
+	struct inode	*vp,
+	xfs_acl_t	*acl,
+	int		*basicperms)
+{
+	struct iattr	iattr;
+	xfs_acl_entry_t	*ap;
+	xfs_acl_entry_t	*gap = NULL;
+	int		i, nomask = 1;
+
+	*basicperms = 1;
+
+	if (acl->acl_cnt == XFS_ACL_NOT_PRESENT)
+		return 0;
+
+	/*
+	 * Copy the u::, g::, o::, and m:: bits from the ACL into the
+	 * mode.  The m:: bits take precedence over the g:: bits.
+	 */
+	iattr.ia_valid = ATTR_MODE;
+	iattr.ia_mode = XFS_I(vp)->i_d.di_mode;
+	iattr.ia_mode &= ~(S_IRWXU|S_IRWXG|S_IRWXO);
+	ap = acl->acl_entry;
+	for (i = 0; i < acl->acl_cnt; ++i) {
+		switch (ap->ae_tag) {
+		case ACL_USER_OBJ:
+			iattr.ia_mode |= ap->ae_perm << 6;
+			break;
+		case ACL_GROUP_OBJ:
+			gap = ap;
+			break;
+		case ACL_MASK:	/* more than just standard modes */
+			nomask = 0;
+			iattr.ia_mode |= ap->ae_perm << 3;
+			*basicperms = 0;
+			break;
+		case ACL_OTHER:
+			iattr.ia_mode |= ap->ae_perm;
+			break;
+		default:	/* more than just standard modes */
+			*basicperms = 0;
+			break;
+		}
+		ap++;
+	}
+
+	/* Set the group bits from ACL_GROUP_OBJ if there's no ACL_MASK */
+	if (gap && nomask)
+		iattr.ia_mode |= gap->ae_perm << 3;
+
+	return xfs_setattr(XFS_I(vp), &iattr, 0, sys_cred);
+}
+
+/*
+ * The permissions for the special ACL entries (u::, g::[m::], o::) are
+ * actually stored in the file mode (if there is both a group and a mask,
+ * the group is stored in the ACL entry and the mask is stored on the file).
+ * This allows the mode to remain automatically in sync with the ACL without
+ * the need for a call-back to the ACL system at every point where the mode
+ * could change.  This function takes the permissions from the specified mode
+ * and places it in the supplied ACL.
+ *
+ * This implementation draws its validity from the fact that, when the ACL
+ * was assigned, the mode was copied from the ACL.
+ * If the mode did not change, therefore, the mode remains exactly what was
+ * taken from the special ACL entries at assignment.
+ * If a subsequent chmod() was done, the POSIX spec says that the change in
+ * mode must cause an update to the ACL seen at user level and used for
+ * access checks.  Before and after a mode change, therefore, the file mode
+ * most accurately reflects what the special ACL entries should permit/deny.
+ *
+ * CAVEAT: If someone sets the SGI_ACL_FILE attribute directly,
+ *         the existing mode bits will override whatever is in the
+ *         ACL. Similarly, if there is a pre-existing ACL that was
+ *         never in sync with its mode (owing to a bug in 6.5 and
+ *         before), it will now magically (or mystically) be
+ *         synchronized.  This could cause slight astonishment, but
+ *         it is better than inconsistent permissions.
+ *
+ * The supplied ACL is a template that may contain any combination
+ * of special entries.  These are treated as place holders when we fill
+ * out the ACL.  This routine does not add or remove special entries, it
+ * simply unites each special entry with its associated set of permissions.
+ */
+STATIC void
+xfs_acl_sync_mode(
+	mode_t		mode,
+	xfs_acl_t	*acl)
+{
+	int		i, nomask = 1;
+	xfs_acl_entry_t	*ap;
+	xfs_acl_entry_t	*gap = NULL;
+
+	/*
+	 * Set ACL entries. POSIX1003.1eD16 requires that the MASK
+	 * be set instead of the GROUP entry, if there is a MASK.
+	 */
+	for (ap = acl->acl_entry, i = 0; i < acl->acl_cnt; ap++, i++) {
+		switch (ap->ae_tag) {
+		case ACL_USER_OBJ:
+			ap->ae_perm = (mode >> 6) & 0x7;
+			break;
+		case ACL_GROUP_OBJ:
+			gap = ap;
+			break;
+		case ACL_MASK:
+			nomask = 0;
+			ap->ae_perm = (mode >> 3) & 0x7;
+			break;
+		case ACL_OTHER:
+			ap->ae_perm = mode & 0x7;
+			break;
+		default:
+			break;
+		}
+	}
+	/* Set the ACL_GROUP_OBJ if there's no ACL_MASK */
+	if (gap && nomask)
+		gap->ae_perm = (mode >> 3) & 0x7;
+}
+
+/*
+ * When inheriting an Access ACL from a directory Default ACL,
+ * the ACL bits are set to the intersection of the ACL default
+ * permission bits and the file permission bits in mode. If there
+ * are no permission bits on the file then we must not give them
+ * the ACL. This is what what makes umask() work with ACLs.
+ */
+STATIC void
+xfs_acl_filter_mode(
+	mode_t		mode,
+	xfs_acl_t	*acl)
+{
+	int		i, nomask = 1;
+	xfs_acl_entry_t	*ap;
+	xfs_acl_entry_t	*gap = NULL;
+
+	/*
+	 * Set ACL entries. POSIX1003.1eD16 requires that the MASK
+	 * be merged with GROUP entry, if there is a MASK.
+	 */
+	for (ap = acl->acl_entry, i = 0; i < acl->acl_cnt; ap++, i++) {
+		switch (ap->ae_tag) {
+		case ACL_USER_OBJ:
+			ap->ae_perm &= (mode >> 6) & 0x7;
+			break;
+		case ACL_GROUP_OBJ:
+			gap = ap;
+			break;
+		case ACL_MASK:
+			nomask = 0;
+			ap->ae_perm &= (mode >> 3) & 0x7;
+			break;
+		case ACL_OTHER:
+			ap->ae_perm &= mode & 0x7;
+			break;
+		default:
+			break;
+		}
+	}
+	/* Set the ACL_GROUP_OBJ if there's no ACL_MASK */
+	if (gap && nomask)
+		gap->ae_perm &= (mode >> 3) & 0x7;
+}