xfs_attr_remote.c | Explore in Territory

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
 * Copyright (c) 2013 Red Hat, Inc.
 * All Rights Reserved.
 */
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_bit.h"
#include "xfs_mount.h"
#include "xfs_defer.h"
#include "xfs_da_format.h"
#include "xfs_da_btree.h"
#include "xfs_inode.h"
#include "xfs_trans.h"
#include "xfs_bmap.h"
#include "xfs_attr.h"
#include "xfs_attr_remote.h"
#include "xfs_trace.h"
#include "xfs_error.h"
#include "xfs_health.h"

#define ATTR_RMTVALUE_MAPSIZE …

/*
 * Remote Attribute Values
 * =======================
 *
 * Remote extended attribute values are conceptually simple -- they're written
 * to data blocks mapped by an inode's attribute fork, and they have an upper
 * size limit of 64k.  Setting a value does not involve the XFS log.
 *
 * However, on a v5 filesystem, maximally sized remote attr values require one
 * block more than 64k worth of space to hold both the remote attribute value
 * header (64 bytes).  On a 4k block filesystem this results in a 68k buffer;
 * on a 64k block filesystem, this would be a 128k buffer.  Note that the log
 * format can only handle a dirty buffer of XFS_MAX_BLOCKSIZE length (64k).
 * Therefore, we /must/ ensure that remote attribute value buffers never touch
 * the logging system and therefore never have a log item.
 */

/* How many bytes can be stored in a remote value buffer? */
inline unsigned int
xfs_attr3_rmt_buf_space(
	struct xfs_mount	*mp)
{ … }

/* Compute number of fsblocks needed to store a remote attr value */
unsigned int
xfs_attr3_rmt_blocks(
	struct xfs_mount	*mp,
	unsigned int		attrlen)
{ … }

/*
 * Checking of the remote attribute header is split into two parts. The verifier
 * does CRC, location and bounds checking, the unpacking function checks the
 * attribute parameters and owner.
 */
static xfs_failaddr_t
xfs_attr3_rmt_hdr_ok(
	void			*ptr,
	xfs_ino_t		ino,
	uint32_t		offset,
	uint32_t		size,
	xfs_daddr_t		bno)
{ … }

static xfs_failaddr_t
xfs_attr3_rmt_verify(
	struct xfs_mount	*mp,
	struct xfs_buf		*bp,
	void			*ptr,
	xfs_daddr_t		bno)
{ … }

static int
__xfs_attr3_rmt_read_verify(
	struct xfs_buf	*bp,
	bool		check_crc,
	xfs_failaddr_t	*failaddr)
{ … }

static void
xfs_attr3_rmt_read_verify(
	struct xfs_buf	*bp)
{ … }

static xfs_failaddr_t
xfs_attr3_rmt_verify_struct(
	struct xfs_buf	*bp)
{ … }

static void
xfs_attr3_rmt_write_verify(
	struct xfs_buf	*bp)
{ … }

const struct xfs_buf_ops xfs_attr3_rmt_buf_ops = …;

STATIC int
xfs_attr3_rmt_hdr_set(
	struct xfs_mount	*mp,
	void			*ptr,
	xfs_ino_t		ino,
	uint32_t		offset,
	uint32_t		size,
	xfs_daddr_t		bno)
{ … }

/*
 * Helper functions to copy attribute data in and out of the one disk extents
 */
STATIC int
xfs_attr_rmtval_copyout(
	struct xfs_mount	*mp,
	struct xfs_buf		*bp,
	struct xfs_inode	*dp,
	xfs_ino_t		owner,
	unsigned int		*offset,
	unsigned int		*valuelen,
	uint8_t			**dst)
{ … }

STATIC void
xfs_attr_rmtval_copyin(
	struct xfs_mount *mp,
	struct xfs_buf	*bp,
	xfs_ino_t	ino,
	unsigned int	*offset,
	unsigned int	*valuelen,
	uint8_t		**src)
{ … }

/*
 * Read the value associated with an attribute from the out-of-line buffer
 * that we stored it in.
 *
 * Returns 0 on successful retrieval, otherwise an error.
 */
int
xfs_attr_rmtval_get(
	struct xfs_da_args	*args)
{ … }

/*
 * Find a "hole" in the attribute address space large enough for us to drop the
 * new attributes value into
 */
int
xfs_attr_rmt_find_hole(
	struct xfs_da_args	*args)
{ … }

int
xfs_attr_rmtval_set_value(
	struct xfs_da_args	*args)
{ … }

/* Mark stale any incore buffers for the remote value. */
int
xfs_attr_rmtval_stale(
	struct xfs_inode	*ip,
	struct xfs_bmbt_irec	*map,
	xfs_buf_flags_t		incore_flags)
{ … }

/*
 * Find a hole for the attr and store it in the delayed attr context.  This
 * initializes the context to roll through allocating an attr extent for a
 * delayed attr operation
 */
int
xfs_attr_rmtval_find_space(
	struct xfs_attr_intent		*attr)
{ … }

/*
 * Write one block of the value associated with an attribute into the
 * out-of-line buffer that we have defined for it. This is similar to a subset
 * of xfs_attr_rmtval_set, but records the current block to the delayed attr
 * context, and leaves transaction handling to the caller.
 */
int
xfs_attr_rmtval_set_blk(
	struct xfs_attr_intent		*attr)
{ … }

/*
 * Remove the value associated with an attribute by deleting the
 * out-of-line buffer that it is stored on.
 */
int
xfs_attr_rmtval_invalidate(
	struct xfs_da_args	*args)
{ … }

/*
 * Remove the value associated with an attribute by deleting the out-of-line
 * buffer that it is stored on. Returns -EAGAIN for the caller to refresh the
 * transaction and re-call the function.  Callers should keep calling this
 * routine until it returns something other than -EAGAIN.
 */
int
xfs_attr_rmtval_remove(
	struct xfs_attr_intent		*attr)
{ … }
linux/fs/xfs/libxfs/xfs_attr_remote.c
