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linux/fs/xfs/scrub/symlink.c
Darrick J. Wong 2651923d8d xfs: online repair of symbolic links
If a symbolic link target looks bad, try to sift through the rubble to
find as much of the target buffer that we can, and stage a new target
(short or remote format as needed) in a temporary file and use the
atomic extent swapping mechanism to commit the results.  In the worst
case, we replace the target with an overly long filename that cannot
possibly resolve.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-04-15 14:58:58 -07:00

92 lines
2.1 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2017-2023 Oracle. All Rights Reserved.
* Author: Darrick J. Wong <djwong@kernel.org>
*/
#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_symlink.h"
#include "xfs_health.h"
#include "xfs_symlink_remote.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/health.h"
#include "scrub/repair.h"
/* Set us up to scrub a symbolic link. */
int
xchk_setup_symlink(
struct xfs_scrub *sc)
{
unsigned int resblks = 0;
int error;
/* Allocate the buffer without the inode lock held. */
sc->buf = kvzalloc(XFS_SYMLINK_MAXLEN + 1, XCHK_GFP_FLAGS);
if (!sc->buf)
return -ENOMEM;
if (xchk_could_repair(sc)) {
error = xrep_setup_symlink(sc, &resblks);
if (error)
return error;
}
return xchk_setup_inode_contents(sc, resblks);
}
/* Symbolic links. */
int
xchk_symlink(
struct xfs_scrub *sc)
{
struct xfs_inode *ip = sc->ip;
struct xfs_ifork *ifp;
loff_t len;
int error = 0;
if (!S_ISLNK(VFS_I(ip)->i_mode))
return -ENOENT;
if (xchk_file_looks_zapped(sc, XFS_SICK_INO_SYMLINK_ZAPPED)) {
xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
return 0;
}
ifp = xfs_ifork_ptr(ip, XFS_DATA_FORK);
len = ip->i_disk_size;
/* Plausible size? */
if (len > XFS_SYMLINK_MAXLEN || len <= 0) {
xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
return 0;
}
/* Inline symlink? */
if (ifp->if_format == XFS_DINODE_FMT_LOCAL) {
if (len > xfs_inode_data_fork_size(ip) ||
len > strnlen(ifp->if_data, xfs_inode_data_fork_size(ip)))
xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
return 0;
}
/* Remote symlink; must read the contents. */
error = xfs_symlink_remote_read(sc->ip, sc->buf);
if (!xchk_fblock_process_error(sc, XFS_DATA_FORK, 0, &error))
return error;
if (strnlen(sc->buf, XFS_SYMLINK_MAXLEN) < len)
xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
/* If a remote symlink is clean, it is clearly not zapped. */
xchk_mark_healthy_if_clean(sc, XFS_SICK_INO_SYMLINK_ZAPPED);
return 0;
}