xfs_parent.c | Explore in Territory

// 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"
#include "xfs_attr_item.h"
#include "xfs_health.h"

struct kmem_cache		*xfs_parent_args_cache;

/*
 * 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)
{ … }

/* Return true if parent pointer attr value is valid. */
bool
xfs_parent_valuecheck(
	struct xfs_mount		*mp,
	const void			*value,
	size_t				valuelen)
{ … }

/* 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)
{ … }

/* 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)
{ … }

/*
 * Initialize the parent pointer arguments structure.  Caller must have zeroed
 * the contents of @args.  @tp is only required for updates.
 */
static void
xfs_parent_da_args_init(
	struct xfs_da_args	*args,
	struct xfs_trans	*tp,
	struct xfs_parent_rec	*rec,
	struct xfs_inode	*child,
	xfs_ino_t		owner,
	const struct xfs_name	*parent_name)
{ … }

/* Make sure the incore state is ready for a parent pointer query/update. */
static inline int
xfs_parent_iread_extents(
	struct xfs_trans	*tp,
	struct xfs_inode	*child)
{ … }

/* Add a parent pointer to reflect a dirent addition. */
int
xfs_parent_addname(
	struct xfs_trans	*tp,
	struct xfs_parent_args	*ppargs,
	struct xfs_inode	*dp,
	const struct xfs_name	*parent_name,
	struct xfs_inode	*child)
{ … }

/* Remove a parent pointer to reflect a dirent removal. */
int
xfs_parent_removename(
	struct xfs_trans	*tp,
	struct xfs_parent_args	*ppargs,
	struct xfs_inode	*dp,
	const struct xfs_name	*parent_name,
	struct xfs_inode	*child)
{ … }

/* Replace one parent pointer with another to reflect a rename. */
int
xfs_parent_replacename(
	struct xfs_trans	*tp,
	struct xfs_parent_args	*ppargs,
	struct xfs_inode	*old_dp,
	const struct xfs_name	*old_name,
	struct xfs_inode	*new_dp,
	const struct xfs_name	*new_name,
	struct xfs_inode	*child)
{ … }

/*
 * Extract parent pointer information from any parent pointer xattr into
 * @parent_ino/gen.  The last two parameters can be NULL pointers.
 *
 * Returns 0 if this is not a parent pointer xattr at all; or -EFSCORRUPTED for
 * garbage.
 */
int
xfs_parent_from_attr(
	struct xfs_mount	*mp,
	unsigned int		attr_flags,
	const unsigned char	*name,
	unsigned int		namelen,
	const void		*value,
	unsigned int		valuelen,
	xfs_ino_t		*parent_ino,
	uint32_t		*parent_gen)
{ … }

/*
 * Look up a parent pointer record (@parent_name -> @pptr) of @ip.
 *
 * Caller must hold at least ILOCK_SHARED.  The scratchpad need not be
 * initialized.
 *
 * Returns 0 if the pointer is found, -ENOATTR if there is no match, or a
 * negative errno.
 */
int
xfs_parent_lookup(
	struct xfs_trans		*tp,
	struct xfs_inode		*ip,
	const struct xfs_name		*parent_name,
	struct xfs_parent_rec		*pptr,
	struct xfs_da_args		*scratch)
{ … }

/* Sanity-check a parent pointer before we try to perform repairs. */
static inline bool
xfs_parent_sanity_check(
	struct xfs_mount		*mp,
	const struct xfs_name		*parent_name,
	const struct xfs_parent_rec	*pptr)
{ … }


/*
 * Attach the parent pointer (@parent_name -> @pptr) to @ip immediately.
 * Caller must not have a transaction or hold the ILOCK.  This is for
 * specialized repair functions only.  The scratchpad need not be initialized.
 */
int
xfs_parent_set(
	struct xfs_inode	*ip,
	xfs_ino_t		owner,
	const struct xfs_name	*parent_name,
	struct xfs_parent_rec	*pptr,
	struct xfs_da_args	*scratch)
{ … }

/*
 * Remove the parent pointer (@parent_name -> @pptr) from @ip immediately.
 * Caller must not have a transaction or hold the ILOCK.  This is for
 * specialized repair functions only.  The scratchpad need not be initialized.
 */
int
xfs_parent_unset(
	struct xfs_inode		*ip,
	xfs_ino_t			owner,
	const struct xfs_name		*parent_name,
	struct xfs_parent_rec		*pptr,
	struct xfs_da_args		*scratch)
{ … }
linux/fs/xfs/libxfs/xfs_parent.c
