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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2022-2024 Oracle.
* All rights reserved.
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_format.h"
#include "xfs_da_format.h"
#include "xfs_log_format.h"
#include "xfs_shared.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_bmap_btree.h"
#include "xfs_inode.h"
#include "xfs_error.h"
#include "xfs_trace.h"
#include "xfs_trans.h"
#include "xfs_da_btree.h"
#include "xfs_attr.h"
#include "xfs_dir2.h"
#include "xfs_dir2_priv.h"
#include "xfs_attr_sf.h"
#include "xfs_bmap.h"
#include "xfs_defer.h"
#include "xfs_log.h"
#include "xfs_xattr.h"
#include "xfs_parent.h"
#include "xfs_trans_space.h"
/*
* Parent pointer attribute handling.
*
* Because the attribute name is a filename component, it will never be longer
* than 255 bytes and must not contain nulls or slashes. These are roughly the
* same constraints that apply to attribute names.
*
* The attribute value must always be a struct xfs_parent_rec. This means the
* attribute will never be in remote format because 12 bytes is nowhere near
* xfs_attr_leaf_entsize_local_max() (~75% of block size).
*
* Creating a new parent attribute will always create a new attribute - there
* should never, ever be an existing attribute in the tree for a new inode.
* ENOSPC behavior is problematic - creating the inode without the parent
* pointer is effectively a corruption, so we allow parent attribute creation
* to dip into the reserve block pool to avoid unexpected ENOSPC errors from
* occurring.
*/
/* Return true if parent pointer attr name is valid. */
bool
xfs_parent_namecheck(
unsigned int attr_flags,
const void *name,
size_t length)
{
/*
* Parent pointers always use logged operations, so there should never
* be incomplete xattrs.
*/
if (attr_flags & XFS_ATTR_INCOMPLETE)
return false;
return xfs_dir2_namecheck(name, length);
}
/* Return true if parent pointer attr value is valid. */
bool
xfs_parent_valuecheck(
struct xfs_mount *mp,
const void *value,
size_t valuelen)
{
const struct xfs_parent_rec *rec = value;
if (!xfs_has_parent(mp))
return false;
/* The xattr value must be a parent record. */
if (valuelen != sizeof(struct xfs_parent_rec))
return false;
/* The parent record must be local. */
if (value == NULL)
return false;
/* The parent inumber must be valid. */
if (!xfs_verify_dir_ino(mp, be64_to_cpu(rec->p_ino)))
return false;
return true;
}
/* Compute the attribute name hash for a parent pointer. */
xfs_dahash_t
xfs_parent_hashval(
struct xfs_mount *mp,
const uint8_t *name,
int namelen,
xfs_ino_t parent_ino)
{
struct xfs_name xname = {
.name = name,
.len = namelen,
};
/*
* Use the same dirent name hash as would be used on the directory, but
* mix in the parent inode number to avoid collisions on hardlinked
* files with identical names but different parents.
*/
return xfs_dir2_hashname(mp, &xname) ^
upper_32_bits(parent_ino) ^ lower_32_bits(parent_ino);
}
/* Compute the attribute name hash from the xattr components. */
xfs_dahash_t
xfs_parent_hashattr(
struct xfs_mount *mp,
const uint8_t *name,
int namelen,
const void *value,
int valuelen)
{
const struct xfs_parent_rec *rec = value;
/* Requires a local attr value in xfs_parent_rec format */
if (valuelen != sizeof(struct xfs_parent_rec)) {
ASSERT(valuelen == sizeof(struct xfs_parent_rec));
return 0;
}
if (!value) {
ASSERT(value != NULL);
return 0;
}
return xfs_parent_hashval(mp, name, namelen, be64_to_cpu(rec->p_ino));
}
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