360 lines
7.6 KiB
C
360 lines
7.6 KiB
C
/*
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* Copyright (C) 2007 Red Hat. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License v2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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#include <linux/fs.h>
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#include <linux/string.h>
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#include <linux/xattr.h>
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#include <linux/posix_acl_xattr.h>
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#include <linux/posix_acl.h>
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#include <linux/sched.h>
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#include "ctree.h"
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#include "btrfs_inode.h"
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#include "xattr.h"
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#ifdef CONFIG_FS_POSIX_ACL
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static void btrfs_update_cached_acl(struct inode *inode,
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struct posix_acl **p_acl,
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struct posix_acl *acl)
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{
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spin_lock(&inode->i_lock);
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if (*p_acl && *p_acl != BTRFS_ACL_NOT_CACHED)
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posix_acl_release(*p_acl);
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*p_acl = posix_acl_dup(acl);
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spin_unlock(&inode->i_lock);
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}
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static struct posix_acl *btrfs_get_acl(struct inode *inode, int type)
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{
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int size;
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const char *name;
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char *value = NULL;
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struct posix_acl *acl = NULL, **p_acl;
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switch (type) {
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case ACL_TYPE_ACCESS:
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name = POSIX_ACL_XATTR_ACCESS;
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p_acl = &BTRFS_I(inode)->i_acl;
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break;
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case ACL_TYPE_DEFAULT:
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name = POSIX_ACL_XATTR_DEFAULT;
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p_acl = &BTRFS_I(inode)->i_default_acl;
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break;
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default:
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return ERR_PTR(-EINVAL);
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}
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/* Handle the cached NULL acl case without locking */
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acl = ACCESS_ONCE(*p_acl);
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if (!acl)
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return acl;
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spin_lock(&inode->i_lock);
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acl = *p_acl;
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if (acl != BTRFS_ACL_NOT_CACHED)
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acl = posix_acl_dup(acl);
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spin_unlock(&inode->i_lock);
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if (acl != BTRFS_ACL_NOT_CACHED)
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return acl;
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size = __btrfs_getxattr(inode, name, "", 0);
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if (size > 0) {
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value = kzalloc(size, GFP_NOFS);
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if (!value)
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return ERR_PTR(-ENOMEM);
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size = __btrfs_getxattr(inode, name, value, size);
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if (size > 0) {
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acl = posix_acl_from_xattr(value, size);
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btrfs_update_cached_acl(inode, p_acl, acl);
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}
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kfree(value);
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} else if (size == -ENOENT || size == -ENODATA || size == 0) {
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/* FIXME, who returns -ENOENT? I think nobody */
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acl = NULL;
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btrfs_update_cached_acl(inode, p_acl, acl);
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} else {
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acl = ERR_PTR(-EIO);
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}
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return acl;
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}
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static int btrfs_xattr_get_acl(struct inode *inode, int type,
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void *value, size_t size)
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{
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struct posix_acl *acl;
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int ret = 0;
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acl = btrfs_get_acl(inode, type);
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if (IS_ERR(acl))
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return PTR_ERR(acl);
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if (acl == NULL)
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return -ENODATA;
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ret = posix_acl_to_xattr(acl, value, size);
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posix_acl_release(acl);
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return ret;
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}
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/*
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* Needs to be called with fs_mutex held
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*/
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static int btrfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
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{
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int ret, size = 0;
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const char *name;
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struct posix_acl **p_acl;
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char *value = NULL;
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mode_t mode;
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if (acl) {
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ret = posix_acl_valid(acl);
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if (ret < 0)
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return ret;
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ret = 0;
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}
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switch (type) {
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case ACL_TYPE_ACCESS:
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mode = inode->i_mode;
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ret = posix_acl_equiv_mode(acl, &mode);
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if (ret < 0)
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return ret;
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ret = 0;
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inode->i_mode = mode;
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name = POSIX_ACL_XATTR_ACCESS;
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p_acl = &BTRFS_I(inode)->i_acl;
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break;
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case ACL_TYPE_DEFAULT:
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if (!S_ISDIR(inode->i_mode))
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return acl ? -EINVAL : 0;
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name = POSIX_ACL_XATTR_DEFAULT;
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p_acl = &BTRFS_I(inode)->i_default_acl;
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break;
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default:
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return -EINVAL;
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}
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if (acl) {
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size = posix_acl_xattr_size(acl->a_count);
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value = kmalloc(size, GFP_NOFS);
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if (!value) {
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ret = -ENOMEM;
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goto out;
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}
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ret = posix_acl_to_xattr(acl, value, size);
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if (ret < 0)
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goto out;
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}
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ret = __btrfs_setxattr(inode, name, value, size, 0);
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out:
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kfree(value);
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if (!ret)
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btrfs_update_cached_acl(inode, p_acl, acl);
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return ret;
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}
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static int btrfs_xattr_set_acl(struct inode *inode, int type,
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const void *value, size_t size)
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{
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int ret = 0;
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struct posix_acl *acl = NULL;
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if (value) {
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acl = posix_acl_from_xattr(value, size);
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if (acl == NULL) {
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value = NULL;
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size = 0;
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} else if (IS_ERR(acl)) {
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return PTR_ERR(acl);
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}
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}
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ret = btrfs_set_acl(inode, acl, type);
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posix_acl_release(acl);
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return ret;
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}
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static int btrfs_xattr_acl_access_get(struct inode *inode, const char *name,
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void *value, size_t size)
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{
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return btrfs_xattr_get_acl(inode, ACL_TYPE_ACCESS, value, size);
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}
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static int btrfs_xattr_acl_access_set(struct inode *inode, const char *name,
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const void *value, size_t size, int flags)
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{
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return btrfs_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
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}
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static int btrfs_xattr_acl_default_get(struct inode *inode, const char *name,
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void *value, size_t size)
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{
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return btrfs_xattr_get_acl(inode, ACL_TYPE_DEFAULT, value, size);
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}
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static int btrfs_xattr_acl_default_set(struct inode *inode, const char *name,
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const void *value, size_t size, int flags)
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{
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return btrfs_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
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}
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int btrfs_check_acl(struct inode *inode, int mask)
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{
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struct posix_acl *acl;
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int error = -EAGAIN;
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acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS);
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if (IS_ERR(acl))
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return PTR_ERR(acl);
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if (acl) {
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error = posix_acl_permission(inode, acl, mask);
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posix_acl_release(acl);
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}
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return error;
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}
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/*
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* btrfs_init_acl is already generally called under fs_mutex, so the locking
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* stuff has been fixed to work with that. If the locking stuff changes, we
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* need to re-evaluate the acl locking stuff.
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*/
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int btrfs_init_acl(struct inode *inode, struct inode *dir)
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{
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struct posix_acl *acl = NULL;
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int ret = 0;
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/* this happens with subvols */
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if (!dir)
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return 0;
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if (!S_ISLNK(inode->i_mode)) {
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if (IS_POSIXACL(dir)) {
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acl = btrfs_get_acl(dir, ACL_TYPE_DEFAULT);
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if (IS_ERR(acl))
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return PTR_ERR(acl);
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}
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if (!acl)
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inode->i_mode &= ~current_umask();
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}
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if (IS_POSIXACL(dir) && acl) {
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struct posix_acl *clone;
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mode_t mode;
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if (S_ISDIR(inode->i_mode)) {
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ret = btrfs_set_acl(inode, acl, ACL_TYPE_DEFAULT);
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if (ret)
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goto failed;
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}
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clone = posix_acl_clone(acl, GFP_NOFS);
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ret = -ENOMEM;
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if (!clone)
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goto failed;
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mode = inode->i_mode;
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ret = posix_acl_create_masq(clone, &mode);
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if (ret >= 0) {
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inode->i_mode = mode;
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if (ret > 0) {
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/* we need an acl */
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ret = btrfs_set_acl(inode, clone,
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ACL_TYPE_ACCESS);
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}
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}
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}
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failed:
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posix_acl_release(acl);
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return ret;
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}
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int btrfs_acl_chmod(struct inode *inode)
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{
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struct posix_acl *acl, *clone;
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int ret = 0;
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if (S_ISLNK(inode->i_mode))
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return -EOPNOTSUPP;
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if (!IS_POSIXACL(inode))
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return 0;
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acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS);
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if (IS_ERR(acl) || !acl)
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return PTR_ERR(acl);
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clone = posix_acl_clone(acl, GFP_KERNEL);
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posix_acl_release(acl);
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if (!clone)
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return -ENOMEM;
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ret = posix_acl_chmod_masq(clone, inode->i_mode);
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if (!ret)
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ret = btrfs_set_acl(inode, clone, ACL_TYPE_ACCESS);
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posix_acl_release(clone);
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return ret;
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}
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struct xattr_handler btrfs_xattr_acl_default_handler = {
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.prefix = POSIX_ACL_XATTR_DEFAULT,
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.get = btrfs_xattr_acl_default_get,
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.set = btrfs_xattr_acl_default_set,
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};
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struct xattr_handler btrfs_xattr_acl_access_handler = {
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.prefix = POSIX_ACL_XATTR_ACCESS,
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.get = btrfs_xattr_acl_access_get,
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.set = btrfs_xattr_acl_access_set,
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};
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#else /* CONFIG_FS_POSIX_ACL */
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int btrfs_acl_chmod(struct inode *inode)
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{
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return 0;
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}
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int btrfs_init_acl(struct inode *inode, struct inode *dir)
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{
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return 0;
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}
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int btrfs_check_acl(struct inode *inode, int mask)
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{
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return 0;
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}
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#endif /* CONFIG_FS_POSIX_ACL */
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