linux/fs/xfs/scrub/readdir.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2022-2023 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_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_dir2.h"
#include "xfs_dir2_priv.h"
#include "xfs_trace.h"
#include "xfs_bmap.h"
#include "xfs_trans.h"
#include "xfs_error.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/readdir.h"

/* Call a function for every entry in a shortform directory. */
STATIC int
xchk_dir_walk_sf(
	struct xfs_scrub	*sc,
	struct xfs_inode	*dp,
	xchk_dirent_fn		dirent_fn,
	void			*priv)
{ … }

/* Call a function for every entry in a block directory. */
STATIC int
xchk_dir_walk_block(
	struct xfs_scrub	*sc,
	struct xfs_inode	*dp,
	xchk_dirent_fn		dirent_fn,
	void			*priv)
{ … }

/* Read a leaf-format directory buffer. */
STATIC int
xchk_read_leaf_dir_buf(
	struct xfs_trans	*tp,
	struct xfs_inode	*dp,
	struct xfs_da_geometry	*geo,
	xfs_dir2_off_t		*curoff,
	struct xfs_buf		**bpp)
{ … }

/* Call a function for every entry in a leaf directory. */
STATIC int
xchk_dir_walk_leaf(
	struct xfs_scrub	*sc,
	struct xfs_inode	*dp,
	xchk_dirent_fn		dirent_fn,
	void			*priv)
{ … }

/*
 * Call a function for every entry in a directory.
 *
 * Callers must hold the ILOCK.  File types are XFS_DIR3_FT_*.
 */
int
xchk_dir_walk(
	struct xfs_scrub	*sc,
	struct xfs_inode	*dp,
	xchk_dirent_fn		dirent_fn,
	void			*priv)
{ … }

/*
 * Look up the inode number for an exact name in a directory.
 *
 * Callers must hold the ILOCK.  File types are XFS_DIR3_FT_*.  Names are not
 * checked for correctness.
 */
int
xchk_dir_lookup(
	struct xfs_scrub	*sc,
	struct xfs_inode	*dp,
	const struct xfs_name	*name,
	xfs_ino_t		*ino)
{ … }

/*
 * Try to grab the IOLOCK and ILOCK of sc->ip and ip, returning @ip's lock
 * state.  The caller may have a transaction, so we must use trylock for both
 * IOLOCKs.
 */
static inline unsigned int
xchk_dir_trylock_both(
	struct xfs_scrub	*sc,
	struct xfs_inode	*ip)
{ … }

/*
 * Try for a limited time to grab the IOLOCK and ILOCK of both the scrub target
 * (@sc->ip) and the inode at the other end (@ip) of a directory or parent
 * pointer link so that we can check that link.
 *
 * We do not know ahead of time that the directory tree is /not/ corrupt, so we
 * cannot use the "lock two inode" functions because we do not know that there
 * is not a racing thread trying to take the locks in opposite order.  First
 * take IOLOCK_EXCL of the scrub target, and then try to take IOLOCK_SHARED
 * of @ip to synchronize with the VFS.  Next, take ILOCK_EXCL of the scrub
 * target and @ip to synchronize with XFS.
 *
 * If the trylocks succeed, *lockmode will be set to the locks held for @ip;
 * @sc->ilock_flags will be set for the locks held for @sc->ip; and zero will
 * be returned.  If not, returns -EDEADLOCK to try again; or -ETIMEDOUT if
 * XCHK_TRY_HARDER was set.  Returns -EINTR if the process has been killed.
 */
int
xchk_dir_trylock_for_pptrs(
	struct xfs_scrub	*sc,
	struct xfs_inode	*ip,
	unsigned int		*lockmode)
{ … }