linux/fs/xfs/xfs_acl.c
Dave Chinner 67f2ffe31d xfs: don't change inode mode if ACL update fails
If we get ENOSPC half way through setting the ACL, the inode mode
can still be changed even though the ACL does not exist. Reorder the
operation to only change the mode of the inode if the ACL is set
correctly.

Whilst this does not fix the problem with crash consistency (that requires
attribute addition to be a deferred op) it does prevent ENOSPC and other
non-fatal errors setting an xattr to be handled sanely.

This fixes xfstests generic/449.

Signed-Off-By: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-10-11 10:21:06 -07:00

283 lines
6.1 KiB
C

/*
* Copyright (c) 2008, Christoph Hellwig
* 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_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_acl.h"
#include "xfs_attr.h"
#include "xfs_trace.h"
#include <linux/slab.h>
#include <linux/xattr.h>
#include <linux/posix_acl_xattr.h>
/*
* Locking scheme:
* - all ACL updates are protected by inode->i_mutex, which is taken before
* calling into this file.
*/
STATIC struct posix_acl *
xfs_acl_from_disk(
const struct xfs_acl *aclp,
int len,
int max_entries)
{
struct posix_acl_entry *acl_e;
struct posix_acl *acl;
const struct xfs_acl_entry *ace;
unsigned int count, i;
if (len < sizeof(*aclp))
return ERR_PTR(-EFSCORRUPTED);
count = be32_to_cpu(aclp->acl_cnt);
if (count > max_entries || XFS_ACL_SIZE(count) != len)
return ERR_PTR(-EFSCORRUPTED);
acl = posix_acl_alloc(count, GFP_KERNEL);
if (!acl)
return ERR_PTR(-ENOMEM);
for (i = 0; i < count; i++) {
acl_e = &acl->a_entries[i];
ace = &aclp->acl_entry[i];
/*
* The tag is 32 bits on disk and 16 bits in core.
*
* Because every access to it goes through the core
* format first this is not a problem.
*/
acl_e->e_tag = be32_to_cpu(ace->ae_tag);
acl_e->e_perm = be16_to_cpu(ace->ae_perm);
switch (acl_e->e_tag) {
case ACL_USER:
acl_e->e_uid = xfs_uid_to_kuid(be32_to_cpu(ace->ae_id));
break;
case ACL_GROUP:
acl_e->e_gid = xfs_gid_to_kgid(be32_to_cpu(ace->ae_id));
break;
case ACL_USER_OBJ:
case ACL_GROUP_OBJ:
case ACL_MASK:
case ACL_OTHER:
break;
default:
goto fail;
}
}
return acl;
fail:
posix_acl_release(acl);
return ERR_PTR(-EINVAL);
}
STATIC void
xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl)
{
const struct posix_acl_entry *acl_e;
struct xfs_acl_entry *ace;
int i;
aclp->acl_cnt = cpu_to_be32(acl->a_count);
for (i = 0; i < acl->a_count; i++) {
ace = &aclp->acl_entry[i];
acl_e = &acl->a_entries[i];
ace->ae_tag = cpu_to_be32(acl_e->e_tag);
switch (acl_e->e_tag) {
case ACL_USER:
ace->ae_id = cpu_to_be32(xfs_kuid_to_uid(acl_e->e_uid));
break;
case ACL_GROUP:
ace->ae_id = cpu_to_be32(xfs_kgid_to_gid(acl_e->e_gid));
break;
default:
ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID);
break;
}
ace->ae_perm = cpu_to_be16(acl_e->e_perm);
}
}
struct posix_acl *
xfs_get_acl(struct inode *inode, int type)
{
struct xfs_inode *ip = XFS_I(inode);
struct posix_acl *acl = NULL;
struct xfs_acl *xfs_acl;
unsigned char *ea_name;
int error;
int len;
trace_xfs_get_acl(ip);
switch (type) {
case ACL_TYPE_ACCESS:
ea_name = SGI_ACL_FILE;
break;
case ACL_TYPE_DEFAULT:
ea_name = SGI_ACL_DEFAULT;
break;
default:
BUG();
}
/*
* If we have a cached ACLs value just return it, not need to
* go out to the disk.
*/
len = XFS_ACL_MAX_SIZE(ip->i_mount);
xfs_acl = kmem_zalloc_large(len, KM_SLEEP);
if (!xfs_acl)
return ERR_PTR(-ENOMEM);
error = xfs_attr_get(ip, ea_name, (unsigned char *)xfs_acl,
&len, ATTR_ROOT);
if (error) {
/*
* If the attribute doesn't exist make sure we have a negative
* cache entry, for any other error assume it is transient.
*/
if (error != -ENOATTR)
acl = ERR_PTR(error);
} else {
acl = xfs_acl_from_disk(xfs_acl, len,
XFS_ACL_MAX_ENTRIES(ip->i_mount));
}
kmem_free(xfs_acl);
return acl;
}
int
__xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
{
struct xfs_inode *ip = XFS_I(inode);
unsigned char *ea_name;
int error;
switch (type) {
case ACL_TYPE_ACCESS:
ea_name = SGI_ACL_FILE;
break;
case ACL_TYPE_DEFAULT:
if (!S_ISDIR(inode->i_mode))
return acl ? -EACCES : 0;
ea_name = SGI_ACL_DEFAULT;
break;
default:
return -EINVAL;
}
if (acl) {
struct xfs_acl *xfs_acl;
int len = XFS_ACL_MAX_SIZE(ip->i_mount);
xfs_acl = kmem_zalloc_large(len, KM_SLEEP);
if (!xfs_acl)
return -ENOMEM;
xfs_acl_to_disk(xfs_acl, acl);
/* subtract away the unused acl entries */
len -= sizeof(struct xfs_acl_entry) *
(XFS_ACL_MAX_ENTRIES(ip->i_mount) - acl->a_count);
error = xfs_attr_set(ip, ea_name, (unsigned char *)xfs_acl,
len, ATTR_ROOT);
kmem_free(xfs_acl);
} else {
/*
* A NULL ACL argument means we want to remove the ACL.
*/
error = xfs_attr_remove(ip, ea_name, ATTR_ROOT);
/*
* If the attribute didn't exist to start with that's fine.
*/
if (error == -ENOATTR)
error = 0;
}
if (!error)
set_cached_acl(inode, type, acl);
return error;
}
static int
xfs_set_mode(struct inode *inode, umode_t mode)
{
int error = 0;
if (mode != inode->i_mode) {
struct iattr iattr;
iattr.ia_valid = ATTR_MODE | ATTR_CTIME;
iattr.ia_mode = mode;
iattr.ia_ctime = current_time(inode);
error = xfs_setattr_nonsize(XFS_I(inode), &iattr, XFS_ATTR_NOACL);
}
return error;
}
int
xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
{
umode_t mode;
bool set_mode = false;
int error = 0;
if (!acl)
goto set_acl;
error = -E2BIG;
if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb)))
return error;
if (type == ACL_TYPE_ACCESS) {
error = posix_acl_update_mode(inode, &mode, &acl);
if (error)
return error;
set_mode = true;
}
set_acl:
error = __xfs_set_acl(inode, acl, type);
if (error)
return error;
/*
* We set the mode after successfully updating the ACL xattr because the
* xattr update can fail at ENOSPC and we don't want to change the mode
* if the ACL update hasn't been applied.
*/
if (set_mode)
error = xfs_set_mode(inode, mode);
return error;
}