tempfile.c | Explore in Territory

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (c) 2021-2024 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_log_format.h"
#include "xfs_trans.h"
#include "xfs_inode.h"
#include "xfs_ialloc.h"
#include "xfs_quota.h"
#include "xfs_bmap.h"
#include "xfs_bmap_btree.h"
#include "xfs_trans_space.h"
#include "xfs_dir2.h"
#include "xfs_exchrange.h"
#include "xfs_exchmaps.h"
#include "xfs_defer.h"
#include "xfs_symlink_remote.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/repair.h"
#include "scrub/trace.h"
#include "scrub/tempfile.h"
#include "scrub/tempexch.h"
#include "scrub/xfile.h"

/*
 * Create a temporary file for reconstructing metadata, with the intention of
 * atomically exchanging the temporary file's contents with the file that's
 * being repaired.
 */
int
xrep_tempfile_create(
	struct xfs_scrub	*sc,
	uint16_t		mode)
{ … }

/* Take IOLOCK_EXCL on the temporary file, maybe. */
bool
xrep_tempfile_iolock_nowait(
	struct xfs_scrub	*sc)
{ … }

/*
 * Take the temporary file's IOLOCK while holding a different inode's IOLOCK.
 * In theory nobody else should hold the tempfile's IOLOCK, but we use trylock
 * to avoid deadlocks and lockdep complaints.
 */
int
xrep_tempfile_iolock_polled(
	struct xfs_scrub	*sc)
{ … }

/* Release IOLOCK_EXCL on the temporary file. */
void
xrep_tempfile_iounlock(
	struct xfs_scrub	*sc)
{ … }

/* Prepare the temporary file for metadata updates by grabbing ILOCK_EXCL. */
void
xrep_tempfile_ilock(
	struct xfs_scrub	*sc)
{ … }

/* Try to grab ILOCK_EXCL on the temporary file. */
bool
xrep_tempfile_ilock_nowait(
	struct xfs_scrub	*sc)
{ … }

/* Unlock ILOCK_EXCL on the temporary file after an update. */
void
xrep_tempfile_iunlock(
	struct xfs_scrub	*sc)
{ … }

/*
 * Begin the process of making changes to both the file being scrubbed and
 * the temporary file by taking ILOCK_EXCL on both.
 */
void
xrep_tempfile_ilock_both(
	struct xfs_scrub	*sc)
{ … }

/* Unlock ILOCK_EXCL on both files. */
void
xrep_tempfile_iunlock_both(
	struct xfs_scrub	*sc)
{ … }

/* Release the temporary file. */
void
xrep_tempfile_rele(
	struct xfs_scrub	*sc)
{ … }

/*
 * Make sure that the given range of the data fork of the temporary file is
 * mapped to written blocks.  The caller must ensure that both inodes are
 * joined to the transaction.
 */
int
xrep_tempfile_prealloc(
	struct xfs_scrub	*sc,
	xfs_fileoff_t		off,
	xfs_filblks_t		len)
{ … }

/*
 * Write data to each block of a file.  The given range of the tempfile's data
 * fork must already be populated with written extents.
 */
int
xrep_tempfile_copyin(
	struct xfs_scrub	*sc,
	xfs_fileoff_t		off,
	xfs_filblks_t		len,
	xrep_tempfile_copyin_fn	prep_fn,
	void			*data)
{ … }

/*
 * Set the temporary file's size.  Caller must join the tempfile to the scrub
 * transaction and is responsible for adjusting block mappings as needed.
 */
int
xrep_tempfile_set_isize(
	struct xfs_scrub	*sc,
	unsigned long long	isize)
{ … }

/*
 * Roll a repair transaction involving the temporary file.  Caller must join
 * both the temporary file and the file being scrubbed to the transaction.
 * This function return with both inodes joined to a new scrub transaction,
 * or the usual negative errno.
 */
int
xrep_tempfile_roll_trans(
	struct xfs_scrub	*sc)
{ … }

/*
 * Fill out the mapping exchange request in preparation for atomically
 * committing the contents of a metadata file that we've rebuilt in the temp
 * file.
 */
STATIC int
xrep_tempexch_prep_request(
	struct xfs_scrub	*sc,
	int			whichfork,
	struct xrep_tempexch	*tx)
{ … }

/*
 * Fill out the mapping exchange resource estimation structures in preparation
 * for exchanging the contents of a metadata file that we've rebuilt in the
 * temp file.  Caller must hold IOLOCK_EXCL but not ILOCK_EXCL on both files.
 */
STATIC int
xrep_tempexch_estimate(
	struct xfs_scrub	*sc,
	struct xrep_tempexch	*tx)
{ … }

/*
 * Obtain a quota reservation to make sure we don't hit EDQUOT.  We can skip
 * this if quota enforcement is disabled or if both inodes' dquots are the
 * same.  The qretry structure must be initialized to zeroes before the first
 * call to this function.
 */
STATIC int
xrep_tempexch_reserve_quota(
	struct xfs_scrub		*sc,
	const struct xrep_tempexch	*tx)
{ … }

/*
 * Prepare an existing transaction for an atomic file contents exchange.
 *
 * This function fills out the mapping exchange request and resource estimation
 * structures in preparation for exchanging the contents of a metadata file
 * that has been rebuilt in the temp file.  Next, it reserves space and quota
 * for the transaction.
 *
 * The caller must hold ILOCK_EXCL of the scrub target file and the temporary
 * file.  The caller must join both inodes to the transaction with no unlock
 * flags, and is responsible for dropping both ILOCKs when appropriate.  Only
 * use this when those ILOCKs cannot be dropped.
 */
int
xrep_tempexch_trans_reserve(
	struct xfs_scrub	*sc,
	int			whichfork,
	struct xrep_tempexch	*tx)
{ … }

/*
 * Create a new transaction for a file contents exchange.
 *
 * This function fills out the mapping excahange request and resource
 * estimation structures in preparation for exchanging the contents of a
 * metadata file that has been rebuilt in the temp file.  Next, it reserves
 * space, takes ILOCK_EXCL of both inodes, joins them to the transaction and
 * reserves quota for the transaction.
 *
 * The caller is responsible for dropping both ILOCKs when appropriate.
 */
int
xrep_tempexch_trans_alloc(
	struct xfs_scrub	*sc,
	int			whichfork,
	struct xrep_tempexch	*tx)
{ … }

/*
 * Exchange file mappings (and hence file contents) between the file being
 * repaired and the temporary file.  Returns with both inodes locked and joined
 * to a clean scrub transaction.
 */
int
xrep_tempexch_contents(
	struct xfs_scrub	*sc,
	struct xrep_tempexch	*tx)
{ … }

/*
 * Write local format data from one of the temporary file's forks into the same
 * fork of file being repaired, and exchange the file sizes, if appropriate.
 * Caller must ensure that the file being repaired has enough fork space to
 * hold all the bytes.
 */
void
xrep_tempfile_copyout_local(
	struct xfs_scrub	*sc,
	int			whichfork)
{ … }

/* Decide if a given XFS inode is a temporary file for a repair. */
bool
xrep_is_tempfile(
	const struct xfs_inode	*ip)
{ … }
linux/fs/xfs/scrub/tempfile.c
