text: #include <linux/capability.h>
  #include <linux/fs.h>
  #include <linux/posix_acl.h>
  #include <linux/reiserfs_fs.h>
  #include <linux/errno.h>
  #include <linux/pagemap.h>
  #include <linux/xattr.h>
  #include <linux/posix_acl_xattr.h>
  #include <linux/reiserfs_xattr.h>
  #include <linux/reiserfs_acl.h>
  #include <asm/uaccess.h>
  
  static int reiserfs_set_acl(struct inode *inode, int type,
  			    struct posix_acl *acl);
  
  static int
  xattr_set_acl(struct inode *inode, int type, const void *value, size_t size)
  {
  	struct posix_acl *acl;
  	int error;
  
  	if (!reiserfs_posixacl(inode->i_sb))
  		return -EOPNOTSUPP;
  	if (!is_owner_or_cap(inode))
  		return -EPERM;
  
  	if (value) {
  		acl = posix_acl_from_xattr(value, size);
  		if (IS_ERR(acl)) {
  			return PTR_ERR(acl);
  		} else if (acl) {
  			error = posix_acl_valid(acl);
  			if (error)
  				goto release_and_out;
  		}
  	} else
  		acl = NULL;
  
  	error = reiserfs_set_acl(inode, type, acl);
  
        release_and_out:
  	posix_acl_release(acl);
  	return error;
  }
  
  static int
  xattr_get_acl(struct inode *inode, int type, void *buffer, size_t size)
  {
  	struct posix_acl *acl;
  	int error;
  
  	if (!reiserfs_posixacl(inode->i_sb))
  		return -EOPNOTSUPP;
  
  	acl = reiserfs_get_acl(inode, type);
  	if (IS_ERR(acl))
  		return PTR_ERR(acl);
  	if (acl == NULL)
  		return -ENODATA;
  	error = posix_acl_to_xattr(acl, buffer, size);
  	posix_acl_release(acl);
  
  	return error;
  }
  
  /*
   * Convert from filesystem to in-memory representation.
   */
  static struct posix_acl *posix_acl_from_disk(const void *value, size_t size)
  {
  	const char *end = (char *)value + size;
  	int n, count;
  	struct posix_acl *acl;
  
  	if (!value)
  		return NULL;
  	if (size < sizeof(reiserfs_acl_header))
  		return ERR_PTR(-EINVAL);
  	if (((reiserfs_acl_header *) value)->a_version !=
  	    cpu_to_le32(REISERFS_ACL_VERSION))
  		return ERR_PTR(-EINVAL);
  	value = (char *)value + sizeof(reiserfs_acl_header);
  	count = reiserfs_acl_count(size);
  	if (count < 0)
  		return ERR_PTR(-EINVAL);
  	if (count == 0)
  		return NULL;
  	acl = posix_acl_alloc(count, GFP_NOFS);
  	if (!acl)
  		return ERR_PTR(-ENOMEM);
  	for (n = 0; n < count; n++) {
  		reiserfs_acl_entry *entry = (reiserfs_acl_entry *) value;
  		if ((char *)value + sizeof(reiserfs_acl_entry_short) > end)
  			goto fail;
  		acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
  		acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
  		switch (acl->a_entries[n].e_tag) {
  		case ACL_USER_OBJ:
  		case ACL_GROUP_OBJ:
  		case ACL_MASK:
  		case ACL_OTHER:
  			value = (char *)value +
  			    sizeof(reiserfs_acl_entry_short);
  			acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
  			break;
  
  		case ACL_USER:
  		case ACL_GROUP:
  			value = (char *)value + sizeof(reiserfs_acl_entry);
  			if ((char *)value > end)
  				goto fail;
  			acl->a_entries[n].e_id = le32_to_cpu(entry->e_id);
  			break;
  
  		default:
  			goto fail;
  		}
  	}
  	if (value != end)
  		goto fail;
  	return acl;
  
        fail:
  	posix_acl_release(acl);
  	return ERR_PTR(-EINVAL);
  }
  
  /*
   * Convert from in-memory to filesystem representation.
   */
  static void *posix_acl_to_disk(const struct posix_acl *acl, size_t * size)
  {
  	reiserfs_acl_header *ext_acl;
  	char *e;
  	int n;
  
  	*size = reiserfs_acl_size(acl->a_count);
  	ext_acl = kmalloc(sizeof(reiserfs_acl_header) +
  						  acl->a_count *
  						  sizeof(reiserfs_acl_entry),
  						  GFP_NOFS);
  	if (!ext_acl)
  		return ERR_PTR(-ENOMEM);
  	ext_acl->a_version = cpu_to_le32(REISERFS_ACL_VERSION);
  	e = (char *)ext_acl + sizeof(reiserfs_acl_header);
  	for (n = 0; n < acl->a_count; n++) {
  		reiserfs_acl_entry *entry = (reiserfs_acl_entry *) e;
  		entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
  		entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
  		switch (acl->a_entries[n].e_tag) {
  		case ACL_USER:
  		case ACL_GROUP:
  			entry->e_id = cpu_to_le32(acl->a_entries[n].e_id);
  			e += sizeof(reiserfs_acl_entry);
  			break;
  
  		case ACL_USER_OBJ:
  		case ACL_GROUP_OBJ:
  		case ACL_MASK:
  		case ACL_OTHER:
  			e += sizeof(reiserfs_acl_entry_short);
  			break;
  
  		default:
  			goto fail;
  		}
  	}
  	return (char *)ext_acl;
  
        fail:
  	kfree(ext_acl);
  	return ERR_PTR(-EINVAL);
  }
  
  /*
   * Inode operation get_posix_acl().
   *
   * inode->i_mutex: down
   * BKL held [before 2.5.x]
   */
  struct posix_acl *reiserfs_get_acl(struct inode *inode, int type)
  {
  	char *name, *value;
  	struct posix_acl *acl, **p_acl;
  	int size;
  	int retval;
  	struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
  
  	switch (type) {
  	case ACL_TYPE_ACCESS:
  		name = POSIX_ACL_XATTR_ACCESS;
  		p_acl = &reiserfs_i->i_acl_access;
  		break;
  	case ACL_TYPE_DEFAULT:
  		name = POSIX_ACL_XATTR_DEFAULT;
  		p_acl = &reiserfs_i->i_acl_default;
  		break;
  	default:
  		return ERR_PTR(-EINVAL);
  	}
  
  	if (IS_ERR(*p_acl)) {
  		if (PTR_ERR(*p_acl) == -ENODATA)
  			return NULL;
  	} else if (*p_acl != NULL)
  		return posix_acl_dup(*p_acl);
  
  	size = reiserfs_xattr_get(inode, name, NULL, 0);
  	if (size < 0) {
  		if (size == -ENODATA || size == -ENOSYS) {
  			*p_acl = ERR_PTR(-ENODATA);
  			return NULL;
  		}
  		return ERR_PTR(size);
  	}
  
  	value = kmalloc(size, GFP_NOFS);
  	if (!value)
  		return ERR_PTR(-ENOMEM);
  
  	retval = reiserfs_xattr_get(inode, name, value, size);
  	if (retval == -ENODATA || retval == -ENOSYS) {
  		/* This shouldn't actually happen as it should have
  		   been caught above.. but just in case */
  		acl = NULL;
  		*p_acl = ERR_PTR(-ENODATA);
  	} else if (retval < 0) {
  		acl = ERR_PTR(retval);
  	} else {
  		acl = posix_acl_from_disk(value, retval);
  		if (!IS_ERR(acl))
  			*p_acl = posix_acl_dup(acl);
  	}
  
  	kfree(value);
  	return acl;
  }
  
  /*
   * Inode operation set_posix_acl().
   *
   * inode->i_mutex: down
   * BKL held [before 2.5.x]
   */
  static int
  reiserfs_set_acl(struct inode *inode, int type, struct posix_acl *acl)
  {
  	char *name;
  	void *value = NULL;
  	struct posix_acl **p_acl;
  	size_t size;
  	int error;
  	struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
  
  	if (S_ISLNK(inode->i_mode))
  		return -EOPNOTSUPP;
  
  	switch (type) {
  	case ACL_TYPE_ACCESS:
  		name = POSIX_ACL_XATTR_ACCESS;
  		p_acl = &reiserfs_i->i_acl_access;
  		if (acl) {
  			mode_t mode = inode->i_mode;
  			error = posix_acl_equiv_mode(acl, &mode);
  			if (error < 0)
  				return error;
  			else {
  				inode->i_mode = mode;
  				if (error == 0)
  					acl = NULL;
  			}
  		}
  		break;
  	case ACL_TYPE_DEFAULT:
  		name = POSIX_ACL_XATTR_DEFAULT;
  		p_acl = &reiserfs_i->i_acl_default;
  		if (!S_ISDIR(inode->i_mode))
  			return acl ? -EACCES : 0;
  		break;
  	default:
  		return -EINVAL;
  	}
  
  	if (acl) {
  		value = posix_acl_to_disk(acl, &size);
  		if (IS_ERR(value))
  			return (int)PTR_ERR(value);
  		error = reiserfs_xattr_set(inode, name, value, size, 0);
  	} else {
  		error = reiserfs_xattr_del(inode, name);
  		if (error == -ENODATA) {
  			/* This may seem odd here, but it means that the ACL was set
  			 * with a value representable with mode bits. If there was
  			 * an ACL before, reiserfs_xattr_del already dirtied the inode.
  			 */
  			mark_inode_dirty(inode);
  			error = 0;
  		}
  	}
  
  	kfree(value);
  
  	if (!error) {
  		/* Release the old one */
  		if (!IS_ERR(*p_acl) && *p_acl)
  			posix_acl_release(*p_acl);
  
  		if (acl == NULL)
  			*p_acl = ERR_PTR(-ENODATA);
  		else
  			*p_acl = posix_acl_dup(acl);
  	}
  
  	return error;
  }
  
  /* dir->i_mutex: locked,
   * inode is new and not released into the wild yet */
  int
  reiserfs_inherit_default_acl(struct inode *dir, struct dentry *dentry,
  			     struct inode *inode)
  {
  	struct posix_acl *acl;
  	int err = 0;
  
  	/* ACLs only get applied to files and directories */
  	if (S_ISLNK(inode->i_mode))
  		return 0;
  
  	/* ACLs can only be used on "new" objects, so if it's an old object
  	 * there is nothing to inherit from */
  	if (get_inode_sd_version(dir) == STAT_DATA_V1)
  		goto apply_umask;
  
  	/* Don't apply ACLs to objects in the .reiserfs_priv tree.. This
  	 * would be useless since permissions are ignored, and a pain because
  	 * it introduces locking cycles */
  	if (is_reiserfs_priv_object(dir)) {
  		reiserfs_mark_inode_private(inode);
  		goto apply_umask;
  	}
  
  	acl = reiserfs_get_acl(dir, ACL_TYPE_DEFAULT);
  	if (IS_ERR(acl)) {
  		if (PTR_ERR(acl) == -ENODATA)
  			goto apply_umask;
  		return PTR_ERR(acl);
  	}
  
  	if (acl) {
  		struct posix_acl *acl_copy;
  		mode_t mode = inode->i_mode;
  		int need_acl;
  
  		/* Copy the default ACL to the default ACL of a new directory */
  		if (S_ISDIR(inode->i_mode)) {
  			err = reiserfs_set_acl(inode, ACL_TYPE_DEFAULT, acl);
  			if (err)
  				goto cleanup;
  		}
  
  		/* Now we reconcile the new ACL and the mode,
  		   potentially modifying both */
  		acl_copy = posix_acl_clone(acl, GFP_NOFS);
  		if (!acl_copy) {
  			err = -ENOMEM;
  			goto cleanup;
  		}
  
  		need_acl = posix_acl_create_masq(acl_copy, &mode);
  		if (need_acl >= 0) {
  			if (mode != inode->i_mode) {
  				inode->i_mode = mode;
  			}
  
  			/* If we need an ACL.. */
  			if (need_acl > 0) {
  				err =
  				    reiserfs_set_acl(inode, ACL_TYPE_ACCESS,
  						     acl_copy);
  				if (err)
  					goto cleanup_copy;
  			}
  		}
  	      cleanup_copy:
  		posix_acl_release(acl_copy);
  	      cleanup:
  		posix_acl_release(acl);
  	} else {
  	      apply_umask:
  		/* no ACL, apply umask */
  		inode->i_mode &= ~current->fs->umask;
  	}
  
  	return err;
  }
  
  /* Looks up and caches the result of the default ACL.
   * We do this so that we don't need to carry the xattr_sem into
   * reiserfs_new_inode if we don't need to */
  int reiserfs_cache_default_acl(struct inode *inode)
  {
  	int ret = 0;
  	if (reiserfs_posixacl(inode->i_sb) && !is_reiserfs_priv_object(inode)) {
  		struct posix_acl *acl;
  		reiserfs_read_lock_xattr_i(inode);
  		reiserfs_read_lock_xattrs(inode->i_sb);
  		acl = reiserfs_get_acl(inode, ACL_TYPE_DEFAULT);
  		reiserfs_read_unlock_xattrs(inode->i_sb);
  		reiserfs_read_unlock_xattr_i(inode);
  		ret = (acl && !IS_ERR(acl));
  		if (ret)
  			posix_acl_release(acl);
  	}
  
  	return ret;
  }
  
  int reiserfs_acl_chmod(struct inode *inode)
  {
  	struct posix_acl *acl, *clone;
  	int error;
  
  	if (S_ISLNK(inode->i_mode))
  		return -EOPNOTSUPP;
  
  	if (get_inode_sd_version(inode) == STAT_DATA_V1 ||
  	    !reiserfs_posixacl(inode->i_sb)) {
  		return 0;
  	}
  
  	reiserfs_read_lock_xattrs(inode->i_sb);
  	acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS);
  	reiserfs_read_unlock_xattrs(inode->i_sb);
  	if (!acl)
  		return 0;
  	if (IS_ERR(acl))
  		return PTR_ERR(acl);
  	clone = posix_acl_clone(acl, GFP_NOFS);
  	posix_acl_release(acl);
  	if (!clone)
  		return -ENOMEM;
  	error = posix_acl_chmod_masq(clone, inode->i_mode);
  	if (!error) {
  		int lock = !has_xattr_dir(inode);
  		reiserfs_write_lock_xattr_i(inode);
  		if (lock)
  			reiserfs_write_lock_xattrs(inode->i_sb);
  		else
  			reiserfs_read_lock_xattrs(inode->i_sb);
  		error = reiserfs_set_acl(inode, ACL_TYPE_ACCESS, clone);
  		if (lock)
  			reiserfs_write_unlock_xattrs(inode->i_sb);
  		else
  			reiserfs_read_unlock_xattrs(inode->i_sb);
  		reiserfs_write_unlock_xattr_i(inode);
  	}
  	posix_acl_release(clone);
  	return error;
  }
  
  static int
  posix_acl_access_get(struct inode *inode, const char *name,
  		     void *buffer, size_t size)
  {
  	if (strlen(name) != sizeof(POSIX_ACL_XATTR_ACCESS) - 1)
  		return -EINVAL;
  	return xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
  }
  
  static int
  posix_acl_access_set(struct inode *inode, const char *name,
  		     const void *value, size_t size, int flags)
  {
  	if (strlen(name) != sizeof(POSIX_ACL_XATTR_ACCESS) - 1)
  		return -EINVAL;
  	return xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
  }
  
  static int posix_acl_access_del(struct inode *inode, const char *name)
  {
  	struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
  	struct posix_acl **acl = &reiserfs_i->i_acl_access;
  	if (strlen(name) != sizeof(POSIX_ACL_XATTR_ACCESS) - 1)
  		return -EINVAL;
  	if (!IS_ERR(*acl) && *acl) {
  		posix_acl_release(*acl);
  		*acl = ERR_PTR(-ENODATA);
  	}
  
  	return 0;
  }
  
  static int
  posix_acl_access_list(struct inode *inode, const char *name, int namelen,
  		      char *out)
  {
  	int len = namelen;
  	if (!reiserfs_posixacl(inode->i_sb))
  		return 0;
  	if (out)
  		memcpy(out, name, len);
  
  	return len;
  }
  
  struct reiserfs_xattr_handler posix_acl_access_handler = {
  	.prefix = POSIX_ACL_XATTR_ACCESS,
  	.get = posix_acl_access_get,
  	.set = posix_acl_access_set,
  	.del = posix_acl_access_del,
  	.list = posix_acl_access_list,
  };
  
  static int
  posix_acl_default_get(struct inode *inode, const char *name,
  		      void *buffer, size_t size)
  {
  	if (strlen(name) != sizeof(POSIX_ACL_XATTR_DEFAULT) - 1)
  		return -EINVAL;
  	return xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
  }
  
  static int
  posix_acl_default_set(struct inode *inode, const char *name,
  		      const void *value, size_t size, int flags)
  {
  	if (strlen(name) != sizeof(POSIX_ACL_XATTR_DEFAULT) - 1)
  		return -EINVAL;
  	return xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
  }
  
  static int posix_acl_default_del(struct inode *inode, const char *name)
  {
  	struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
  	struct posix_acl **acl = &reiserfs_i->i_acl_default;
  	if (strlen(name) != sizeof(POSIX_ACL_XATTR_DEFAULT) - 1)
  		return -EINVAL;
  	if (!IS_ERR(*acl) && *acl) {
  		posix_acl_release(*acl);
  		*acl = ERR_PTR(-ENODATA);
  	}
  
  	return 0;
  }
  
  static int
  posix_acl_default_list(struct inode *inode, const char *name, int namelen,
  		       char *out)
  {
  	int len = namelen;
  	if (!reiserfs_posixacl(inode->i_sb))
  		return 0;
  	if (out)
  		memcpy(out, name, len);
  
  	return len;
  }
  
  struct reiserfs_xattr_handler posix_acl_default_handler = {
  	.prefix = POSIX_ACL_XATTR_DEFAULT,
  	.get = posix_acl_default_get,
  	.set = posix_acl_default_set,
  	.del = posix_acl_default_del,
  	.list = posix_acl_default_list,
  };
  