linux/fs/xfs/scrub/symlink_repair.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (c) 2018-2024 Oracle.  All Rights Reserved.
 * Author: Darrick J. Wong <[email protected]>
 */
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_defer.h"
#include "xfs_btree.h"
#include "xfs_bit.h"
#include "xfs_log_format.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_inode.h"
#include "xfs_inode_fork.h"
#include "xfs_symlink.h"
#include "xfs_bmap.h"
#include "xfs_quota.h"
#include "xfs_da_format.h"
#include "xfs_da_btree.h"
#include "xfs_bmap_btree.h"
#include "xfs_trans_space.h"
#include "xfs_symlink_remote.h"
#include "xfs_exchmaps.h"
#include "xfs_exchrange.h"
#include "xfs_health.h"
#include "scrub/xfs_scrub.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/trace.h"
#include "scrub/repair.h"
#include "scrub/tempfile.h"
#include "scrub/tempexch.h"
#include "scrub/reap.h"

/*
 * Symbolic Link Repair
 * ====================
 *
 * We repair symbolic links by reading whatever target data we can find, up to
 * the first NULL byte.  If the recovered target strlen matches i_size, then
 * we rewrite the target.  In all other cases, we replace the target with an
 * overly long string that cannot possibly resolve.  The new target is written
 * into a private hidden temporary file, and then a file contents exchange
 * commits the new symlink target to the file being repaired.
 */

/* Set us up to repair the symlink file. */
int
xrep_setup_symlink(
	struct xfs_scrub	*sc,
	unsigned int		*resblks)
{ … }

/*
 * Try to salvage the pathname from remote blocks.  Returns the number of bytes
 * salvaged or a negative errno.
 */
STATIC ssize_t
xrep_symlink_salvage_remote(
	struct xfs_scrub	*sc)
{ … }

/*
 * Try to salvage an inline symlink's contents.  Returns the number of bytes
 * salvaged or a negative errno.
 */
STATIC ssize_t
xrep_symlink_salvage_inline(
	struct xfs_scrub	*sc)
{ … }

#define DUMMY_TARGET …

/* Salvage whatever we can of the target. */
STATIC int
xrep_symlink_salvage(
	struct xfs_scrub	*sc)
{ … }

STATIC void
xrep_symlink_local_to_remote(
	struct xfs_trans	*tp,
	struct xfs_buf		*bp,
	struct xfs_inode	*ip,
	struct xfs_ifork	*ifp,
	void			*priv)
{ … }

/*
 * Prepare both links' data forks for an exchange.  Promote the tempfile from
 * local format to extents format, and if the file being repaired has a short
 * format data fork, turn it into an empty extent list.
 */
STATIC int
xrep_symlink_swap_prep(
	struct xfs_scrub	*sc,
	bool			temp_local,
	bool			ip_local)
{ … }

/* Exchange the temporary symlink's data fork with the one being repaired. */
STATIC int
xrep_symlink_swap(
	struct xfs_scrub	*sc)
{ … }

/*
 * Free all the remote blocks and reset the data fork.  The caller must join
 * the inode to the transaction.  This function returns with the inode joined
 * to a clean scrub transaction.
 */
STATIC int
xrep_symlink_reset_fork(
	struct xfs_scrub	*sc)
{ … }

/*
 * Reinitialize a link target.  Caller must ensure the inode is joined to
 * the transaction.
 */
STATIC int
xrep_symlink_rebuild(
	struct xfs_scrub	*sc)
{ … }

/* Repair a symbolic link. */
int
xrep_symlink(
	struct xfs_scrub	*sc)
{ … }