diff options
Diffstat (limited to 'fs/xfs/scrub/nlinks_repair.c')
-rw-r--r-- | fs/xfs/scrub/nlinks_repair.c | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/fs/xfs/scrub/nlinks_repair.c b/fs/xfs/scrub/nlinks_repair.c new file mode 100644 index 000000000000..f2b05358a593 --- /dev/null +++ b/fs/xfs/scrub/nlinks_repair.c @@ -0,0 +1,197 @@ +// 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; + 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 = xchk_nlinks_get_record(xnc, ip->i_ino, &obs); + if (error) + goto out_scanlock; + total_links = xchk_nlink_total(&obs); + + /* 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; + } + + /* 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; + } + + /* + * Directories should have at least one "child" (the dot entry) + * 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 an orphanage to adopt the child. Dropping + * a live inode's link count to zero is evil, so leave it alone. + */ + if (total_links == 0) { + if (VFS_I(ip)->i_nlink != 0) + trace_xrep_nlinks_unfixable_inode(mp, ip, &obs); + goto out_scanlock; + } + + /* Perfect match means we're done. */ + if (total_links == VFS_I(ip)->i_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; + } + + return error; +} |