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linux/fs/gfs2/acl.c
Linus Torvalds f16a5e3478 Merge git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-2.6-fixes 
* git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-2.6-fixes:
  GFS2: Fix permissions checking for setflags ioctl()
  GFS2: Don't "get" xattrs for ACLs when ACLs are turned off
  GFS2: Rework reclaiming unlinked dinodes
2010-05-25 08:17:51 -07:00

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/*
* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU General Public License version 2.
*/
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/xattr.h>
#include <linux/posix_acl.h>
#include <linux/posix_acl_xattr.h>
#include <linux/gfs2_ondisk.h>
#include "gfs2.h"
#include "incore.h"
#include "acl.h"
#include "xattr.h"
#include "glock.h"
#include "inode.h"
#include "meta_io.h"
#include "trans.h"
#include "util.h"
static const char *gfs2_acl_name(int type)
{
switch (type) {
case ACL_TYPE_ACCESS:
return GFS2_POSIX_ACL_ACCESS;
case ACL_TYPE_DEFAULT:
return GFS2_POSIX_ACL_DEFAULT;
}
return NULL;
}
static struct posix_acl *gfs2_acl_get(struct gfs2_inode *ip, int type)
{
struct posix_acl *acl;
const char *name;
char *data;
int len;
if (!ip->i_eattr)
return NULL;
acl = get_cached_acl(&ip->i_inode, type);
if (acl != ACL_NOT_CACHED)
return acl;
name = gfs2_acl_name(type);
if (name == NULL)
return ERR_PTR(-EINVAL);
len = gfs2_xattr_acl_get(ip, name, &data);
if (len < 0)
return ERR_PTR(len);
if (len == 0)
return NULL;
acl = posix_acl_from_xattr(data, len);
kfree(data);
return acl;
}
/**
* gfs2_check_acl - Check an ACL to see if we're allowed to do something
* @inode: the file we want to do something to
* @mask: what we want to do
*
* Returns: errno
*/
int gfs2_check_acl(struct inode *inode, int mask)
{
struct posix_acl *acl;
int error;
acl = gfs2_acl_get(GFS2_I(inode), ACL_TYPE_ACCESS);
if (IS_ERR(acl))
return PTR_ERR(acl);
if (acl) {
error = posix_acl_permission(inode, acl, mask);
posix_acl_release(acl);
return error;
}
return -EAGAIN;
}
static int gfs2_set_mode(struct inode *inode, mode_t mode)
{
int error = 0;
if (mode != inode->i_mode) {
struct iattr iattr;
iattr.ia_valid = ATTR_MODE;
iattr.ia_mode = mode;
error = gfs2_setattr_simple(GFS2_I(inode), &iattr);
}
return error;
}
static int gfs2_acl_set(struct inode *inode, int type, struct posix_acl *acl)
{
int error;
int len;
char *data;
const char *name = gfs2_acl_name(type);
BUG_ON(name == NULL);
len = posix_acl_to_xattr(acl, NULL, 0);
if (len == 0)
return 0;
data = kmalloc(len, GFP_NOFS);
if (data == NULL)
return -ENOMEM;
error = posix_acl_to_xattr(acl, data, len);
if (error < 0)
goto out;
error = __gfs2_xattr_set(inode, name, data, len, 0, GFS2_EATYPE_SYS);
if (!error)
set_cached_acl(inode, type, acl);
out:
kfree(data);
return error;
}
int gfs2_acl_create(struct gfs2_inode *dip, struct inode *inode)
{
struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
struct posix_acl *acl, *clone;
mode_t mode = inode->i_mode;
int error = 0;
if (!sdp->sd_args.ar_posix_acl)
return 0;
if (S_ISLNK(inode->i_mode))
return 0;
acl = gfs2_acl_get(dip, ACL_TYPE_DEFAULT);
if (IS_ERR(acl))
return PTR_ERR(acl);
if (!acl) {
mode &= ~current_umask();
if (mode != inode->i_mode)
error = gfs2_set_mode(inode, mode);
return error;
}
if (S_ISDIR(inode->i_mode)) {
error = gfs2_acl_set(inode, ACL_TYPE_DEFAULT, acl);
if (error)
goto out;
}
clone = posix_acl_clone(acl, GFP_NOFS);
error = -ENOMEM;
if (!clone)
goto out;
posix_acl_release(acl);
acl = clone;
error = posix_acl_create_masq(acl, &mode);
if (error < 0)
goto out;
if (error == 0)
goto munge;
error = gfs2_acl_set(inode, ACL_TYPE_ACCESS, acl);
if (error)
goto out;
munge:
error = gfs2_set_mode(inode, mode);
out:
posix_acl_release(acl);
return error;
}
int gfs2_acl_chmod(struct gfs2_inode *ip, struct iattr *attr)
{
struct posix_acl *acl, *clone;
char *data;
unsigned int len;
int error;
acl = gfs2_acl_get(ip, ACL_TYPE_ACCESS);
if (IS_ERR(acl))
return PTR_ERR(acl);
if (!acl)
return gfs2_setattr_simple(ip, attr);
clone = posix_acl_clone(acl, GFP_NOFS);
error = -ENOMEM;
if (!clone)
goto out;
posix_acl_release(acl);
acl = clone;
error = posix_acl_chmod_masq(acl, attr->ia_mode);
if (!error) {
len = posix_acl_to_xattr(acl, NULL, 0);
data = kmalloc(len, GFP_NOFS);
error = -ENOMEM;
if (data == NULL)
goto out;
posix_acl_to_xattr(acl, data, len);
error = gfs2_xattr_acl_chmod(ip, attr, data);
kfree(data);
set_cached_acl(&ip->i_inode, ACL_TYPE_ACCESS, acl);
}
out:
posix_acl_release(acl);
return error;
}
static int gfs2_acl_type(const char *name)
{
if (strcmp(name, GFS2_POSIX_ACL_ACCESS) == 0)
return ACL_TYPE_ACCESS;
if (strcmp(name, GFS2_POSIX_ACL_DEFAULT) == 0)
return ACL_TYPE_DEFAULT;
return -EINVAL;
}
static int gfs2_xattr_system_get(struct dentry *dentry, const char *name,
void *buffer, size_t size, int xtype)
{
struct inode *inode = dentry->d_inode;
struct gfs2_sbd *sdp = GFS2_SB(inode);
struct posix_acl *acl;
int type;
int error;
if (!sdp->sd_args.ar_posix_acl)
return -EOPNOTSUPP;
type = gfs2_acl_type(name);
if (type < 0)
return type;
acl = gfs2_acl_get(GFS2_I(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;
}
static int gfs2_xattr_system_set(struct dentry *dentry, const char *name,
const void *value, size_t size, int flags,
int xtype)
{
struct inode *inode = dentry->d_inode;
struct gfs2_sbd *sdp = GFS2_SB(inode);
struct posix_acl *acl = NULL;
int error = 0, type;
if (!sdp->sd_args.ar_posix_acl)
return -EOPNOTSUPP;
type = gfs2_acl_type(name);
if (type < 0)
return type;
if (flags & XATTR_CREATE)
return -EINVAL;
if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
return value ? -EACCES : 0;
if ((current_fsuid() != inode->i_uid) && !capable(CAP_FOWNER))
return -EPERM;
if (S_ISLNK(inode->i_mode))
return -EOPNOTSUPP;
if (!value)
goto set_acl;
acl = posix_acl_from_xattr(value, size);
if (!acl) {
/*
* acl_set_file(3) may request that we set default ACLs with
* zero length -- defend (gracefully) against that here.
*/
goto out;
}
if (IS_ERR(acl)) {
error = PTR_ERR(acl);
goto out;
}
error = posix_acl_valid(acl);
if (error)
goto out_release;
error = -EINVAL;
if (acl->a_count > GFS2_ACL_MAX_ENTRIES)
goto out_release;
if (type == ACL_TYPE_ACCESS) {
mode_t mode = inode->i_mode;
error = posix_acl_equiv_mode(acl, &mode);
if (error <= 0) {
posix_acl_release(acl);
acl = NULL;
if (error < 0)
return error;
}
error = gfs2_set_mode(inode, mode);
if (error)
goto out_release;
}
set_acl:
error = __gfs2_xattr_set(inode, name, value, size, 0, GFS2_EATYPE_SYS);
if (!error) {
if (acl)
set_cached_acl(inode, type, acl);
else
forget_cached_acl(inode, type);
}
out_release:
posix_acl_release(acl);
out:
return error;
}
const struct xattr_handler gfs2_xattr_system_handler = {
.prefix = XATTR_SYSTEM_PREFIX,
.flags = GFS2_EATYPE_SYS,
.get = gfs2_xattr_system_get,
.set = gfs2_xattr_system_set,
};
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