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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2021 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_icache.h"
#include "xfs_bmap_util.h"
#include "xfs_iwalk.h"
#include "xfs_ialloc.h"
#include "xfs_sb.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/repair.h"
#include "scrub/xfarray.h"
#include "scrub/iscan.h"
#include "scrub/nlinks.h"
#include "scrub/trace.h"
#include "scrub/orphanage.h"
/*
* Live Inode Link Count Repair
* ============================
*
* Use the live inode link count information that we collected to replace the
* nlink values of the incore inodes. A scrub->repair cycle should have left
* the live data and hooks active, so this is safe so long as we make sure the
* inode is locked.
*/
/* Set up to repair inode link counts. */
int
xrep_setup_nlinks(
struct xfs_scrub *sc)
{
return xrep_orphanage_try_create(sc);
}
/*
* Correct the link count of the given inode. Because we have to grab locks
* and resources in a certain order, it's possible that this will be a no-op.
*/
STATIC int
xrep_nlinks_repair_inode(
struct xchk_nlink_ctrs *xnc)
{
struct xchk_nlink obs;
struct xfs_scrub *sc = xnc->sc;
struct xfs_mount *mp = sc->mp;
struct xfs_inode *ip = sc->ip;
uint64_t total_links;
unsigned int actual_nlink;
int error;
xfs_ilock(ip, XFS_IOLOCK_EXCL);
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_link, 0, 0, 0, &sc->tp);
if (error)
goto out_iolock;
xfs_ilock(ip, XFS_ILOCK_EXCL);
xfs_trans_ijoin(sc->tp, ip, 0);
mutex_lock(&xnc->lock);
if (xchk_iscan_aborted(&xnc->collect_iscan)) {
error = -ECANCELED;
goto out_scanlock;
}
error = xfarray_load_sparse(xnc->nlinks, ip->i_ino, &obs);
if (error)
goto out_scanlock;
total_links = xchk_nlink_total(&obs);
actual_nlink = VFS_I(ip)->i_nlink;
/* Cannot set more than the maxiumum possible link count. */
if (total_links > U32_MAX) {
trace_xrep_nlinks_unfixable_inode(mp, ip, &obs);
goto out_scanlock;
}
/*
* Linked directories should have at least one "child" (the dot entry)
* pointing up to them.
*/
if (S_ISDIR(VFS_I(ip)->i_mode) && actual_nlink > 0 && obs.child == 0) {
trace_xrep_nlinks_unfixable_inode(mp, ip, &obs);
goto out_scanlock;
}
/* Non-directories cannot have directories pointing up to them. */
if (!S_ISDIR(VFS_I(ip)->i_mode) && obs.child != 0) {
trace_xrep_nlinks_unfixable_inode(mp, ip, &obs);
goto out_scanlock;
}
/*
* We did not find any links to this inode. If the inode agrees, we
* have nothing further to do. If not, the inode has a nonzero link
* count and we don't have anywhere to graft the child onto. Dropping
* a live inode's link count to zero can cause unexpected shutdowns in
* inactivation, so leave it alone.
*/
if (total_links == 0) {
if (actual_nlink != 0)
trace_xrep_nlinks_unfixable_inode(mp, ip, &obs);
goto out_scanlock;
}
/* Perfect match means we're done. */
if (total_links == actual_nlink)
goto out_scanlock;
mutex_unlock(&xnc->lock);
/* Commit the new link count. */
trace_xrep_nlinks_update_inode(mp, ip, &obs);
set_nlink(VFS_I(ip), total_links);
xfs_trans_log_inode(sc->tp, ip, XFS_ILOG_CORE);
error = xfs_trans_commit(sc->tp);
sc->tp = NULL;
if (error)
goto out_ilock;
xfs_iunlock(ip, XFS_ILOCK_EXCL);
xfs_iunlock(ip, XFS_IOLOCK_EXCL);
return 0;
out_scanlock:
mutex_unlock(&xnc->lock);
xchk_trans_cancel(sc);
out_ilock:
xfs_iunlock(ip, XFS_ILOCK_EXCL);
out_iolock:
xfs_iunlock(ip, XFS_IOLOCK_EXCL);
return error;
}
/* Commit the new inode link counters. */
int
xrep_nlinks(
struct xfs_scrub *sc)
{
struct xchk_nlink_ctrs *xnc = sc->buf;
int error;
/*
* Use the inobt to walk all allocated inodes to compare and fix the
* link counts. If we can't iget the inode, we cannot repair it.
*/
xnc->compare_iscan.iget_tries = 20;
xnc->compare_iscan.iget_retry_delay = HZ / 10;
xchk_iscan_start(&xnc->compare_iscan);
while ((error = xchk_iscan_advance(sc, &xnc->compare_iscan)) == 1) {
ASSERT(sc->ip == NULL);
error = xchk_iscan_iget(sc, &xnc->compare_iscan, &sc->ip);
if (error == -EAGAIN || error == -ECANCELED)
continue;
if (error)
break;
/*
* Commit the scrub transaction so that we can create repair
* transactions with the correct reservations.
*/
xchk_trans_cancel(sc);
error = xrep_nlinks_repair_inode(xnc);
xchk_iscan_mark_visited(&xnc->compare_iscan, sc->ip);
xchk_irele(sc, sc->ip);
sc->ip = NULL;
if (error)
break;
if (xchk_should_terminate(sc, &error))
break;
/*
* Create a new empty transaction so that we can advance the
* iscan cursor without deadlocking if the inobt has a cycle.
* We can only push the inactivation workqueues with an empty
* transaction.
*/
error = xchk_trans_alloc_empty(sc);
if (error)
break;
}
xchk_iscan_finish(&xnc->compare_iscan);
return error;
}
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