linux/fs/xfs/xfs_acl.c
Dave Chinner e0c41089b9 xfs: separate out initial attr_set states
We current use XFS_DAS_UNINIT for several steps in the attr_set
state machine. We use it for setting shortform xattrs, converting
from shortform to leaf, leaf add, leaf-to-node and leaf add. All of
these things are essentially known before we start the state machine
iterating, so we really should separate them out:

XFS_DAS_SF_ADD:
	- tries to do a shortform add
	- on success -> done
	- on ENOSPC converts to leaf, -> XFS_DAS_LEAF_ADD
	- on error, dies.

XFS_DAS_LEAF_ADD:
	- tries to do leaf add
	- on success:
		- inline attr -> done
		- remote xattr || REPLACE -> XFS_DAS_FOUND_LBLK
	- on ENOSPC converts to node, -> XFS_DAS_NODE_ADD
	- on error, dies

XFS_DAS_NODE_ADD:
	- tries to do node add
	- on success:
		- inline attr -> done
		- remote xattr || REPLACE -> XFS_DAS_FOUND_NBLK
	- on error, dies

This makes it easier to understand how the state machine starts
up and sets us up on the path to further state machine
simplifications.

This also converts the DAS state tracepoints to use strings rather
than numbers, as converting between enums and numbers requires
manual counting rather than just reading the name.

This also introduces a XFS_DAS_DONE state so that we can trace
successful operation completions easily.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2022-05-12 15:12:52 +10:00

292 lines
6.2 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2008, Christoph Hellwig
* All Rights Reserved.
*/
#include "xfs.h"
#include "xfs_shared.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_da_format.h"
#include "xfs_da_btree.h"
#include "xfs_attr.h"
#include "xfs_trace.h"
#include "xfs_error.h"
#include "xfs_acl.h"
#include "xfs_trans.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(
struct xfs_mount *mp,
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)) {
XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp,
len);
return ERR_PTR(-EFSCORRUPTED);
}
count = be32_to_cpu(aclp->acl_cnt);
if (count > max_entries || XFS_ACL_SIZE(count) != len) {
XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp,
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 = make_kuid(&init_user_ns,
be32_to_cpu(ace->ae_id));
break;
case ACL_GROUP:
acl_e->e_gid = make_kgid(&init_user_ns,
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(
from_kuid(&init_user_ns, acl_e->e_uid));
break;
case ACL_GROUP:
ace->ae_id = cpu_to_be32(
from_kgid(&init_user_ns, 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, bool rcu)
{
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
struct posix_acl *acl = NULL;
struct xfs_da_args args = {
.dp = ip,
.attr_filter = XFS_ATTR_ROOT,
.valuelen = XFS_ACL_MAX_SIZE(mp),
};
int error;
if (rcu)
return ERR_PTR(-ECHILD);
trace_xfs_get_acl(ip);
switch (type) {
case ACL_TYPE_ACCESS:
args.name = SGI_ACL_FILE;
break;
case ACL_TYPE_DEFAULT:
args.name = SGI_ACL_DEFAULT;
break;
default:
BUG();
}
args.namelen = strlen(args.name);
/*
* If the attribute doesn't exist make sure we have a negative cache
* entry, for any other error assume it is transient.
*/
error = xfs_attr_get(&args);
if (!error) {
acl = xfs_acl_from_disk(mp, args.value, args.valuelen,
XFS_ACL_MAX_ENTRIES(mp));
} else if (error != -ENOATTR) {
acl = ERR_PTR(error);
}
kmem_free(args.value);
return acl;
}
int
__xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
{
struct xfs_inode *ip = XFS_I(inode);
struct xfs_da_args args = {
.dp = ip,
.attr_filter = XFS_ATTR_ROOT,
};
int error;
switch (type) {
case ACL_TYPE_ACCESS:
args.name = SGI_ACL_FILE;
break;
case ACL_TYPE_DEFAULT:
if (!S_ISDIR(inode->i_mode))
return acl ? -EACCES : 0;
args.name = SGI_ACL_DEFAULT;
break;
default:
return -EINVAL;
}
args.namelen = strlen(args.name);
if (acl) {
args.valuelen = XFS_ACL_SIZE(acl->a_count);
args.value = kvzalloc(args.valuelen, GFP_KERNEL);
if (!args.value)
return -ENOMEM;
xfs_acl_to_disk(args.value, acl);
}
error = xfs_attr_set(&args);
kmem_free(args.value);
/*
* If the attribute didn't exist to start with that's fine.
*/
if (!acl && error == -ENOATTR)
error = 0;
if (!error)
set_cached_acl(inode, type, acl);
return error;
}
static int
xfs_acl_set_mode(
struct inode *inode,
umode_t mode)
{
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
struct xfs_trans *tp;
int error;
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp);
if (error)
return error;
xfs_ilock(ip, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
inode->i_mode = mode;
inode->i_ctime = current_time(inode);
xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
if (xfs_has_wsync(mp))
xfs_trans_set_sync(tp);
return xfs_trans_commit(tp);
}
int
xfs_set_acl(struct user_namespace *mnt_userns, 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(mnt_userns, inode, &mode, &acl);
if (error)
return error;
set_mode = true;
}
set_acl:
/*
* 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.
*/
error = __xfs_set_acl(inode, acl, type);
if (!error && set_mode && mode != inode->i_mode)
error = xfs_acl_set_mode(inode, mode);
return error;
}
/*
* Invalidate any cached ACLs if the user has bypassed the ACL interface.
* We don't validate the content whatsoever so it is caller responsibility to
* provide data in valid format and ensure i_mode is consistent.
*/
void
xfs_forget_acl(
struct inode *inode,
const char *name)
{
if (!strcmp(name, SGI_ACL_FILE))
forget_cached_acl(inode, ACL_TYPE_ACCESS);
else if (!strcmp(name, SGI_ACL_DEFAULT))
forget_cached_acl(inode, ACL_TYPE_DEFAULT);
}