diff options
author | Jakub Kicinski <kuba@kernel.org> | 2024-03-22 02:14:13 +0300 |
---|---|---|
committer | Jakub Kicinski <kuba@kernel.org> | 2024-03-22 02:15:08 +0300 |
commit | 537c2e91d3549e5d6020bb0576cf9b54a845255f (patch) | |
tree | c09e8a1b7d733cde19b0c72678c28fb2bc97ff6b /fs/xfs/scrub/nlinks_repair.c | |
parent | 237bb5f7f7f55ec5f773469a974c61a49c298625 (diff) | |
parent | cba9ffdb9913dfe6be29f049ce920ce451ce7cc4 (diff) | |
download | linux-537c2e91d3549e5d6020bb0576cf9b54a845255f.tar.xz |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Cross-merge networking fixes after downstream PR.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'fs/xfs/scrub/nlinks_repair.c')
-rw-r--r-- | fs/xfs/scrub/nlinks_repair.c | 223 |
1 files changed, 223 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..b87618322f55 --- /dev/null +++ b/fs/xfs/scrub/nlinks_repair.c @@ -0,0 +1,223 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (c) 2021-2024 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/xfile.h" +#include "scrub/xfarray.h" +#include "scrub/iscan.h" +#include "scrub/nlinks.h" +#include "scrub/trace.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. + */ + +/* + * 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; + uint64_t actual_nlink; + bool dirty = false; + int error; + + xchk_ilock(sc, XFS_IOLOCK_EXCL); + + error = xfs_trans_alloc(mp, &M_RES(mp)->tr_link, 0, 0, 0, &sc->tp); + if (error) + return error; + + xchk_ilock(sc, 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; + + /* + * We're done accessing the shared scan data, so we can drop the lock. + * We still hold @ip's ILOCK, so its link count cannot change. + */ + mutex_unlock(&xnc->lock); + + total_links = xchk_nlink_total(ip, &obs); + actual_nlink = VFS_I(ip)->i_nlink; + + /* + * Non-directories cannot have directories pointing up to them. + * + * We previously set error to zero, but set it again because one static + * checker author fears that programmers will fail to maintain this + * invariant and built their tool to flag this as a security risk. A + * different tool author made their bot complain about the redundant + * store. This is a never-ending and stupid battle; both tools missed + * *actual bugs* elsewhere; and I no longer care. + */ + if (!S_ISDIR(VFS_I(ip)->i_mode) && obs.children != 0) { + trace_xrep_nlinks_unfixable_inode(mp, ip, &obs); + error = 0; + goto out_trans; + } + + /* + * 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_trans; + } + + /* Commit the new link count if it changed. */ + if (total_links != actual_nlink) { + if (total_links > XFS_MAXLINK) { + trace_xrep_nlinks_unfixable_inode(mp, ip, &obs); + goto out_trans; + } + + trace_xrep_nlinks_update_inode(mp, ip, &obs); + + set_nlink(VFS_I(ip), total_links); + dirty = true; + } + + if (!dirty) { + error = 0; + goto out_trans; + } + + xfs_trans_log_inode(sc->tp, ip, XFS_ILOG_CORE); + + error = xrep_trans_commit(sc); + xchk_iunlock(sc, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL); + return error; + +out_scanlock: + mutex_unlock(&xnc->lock); +out_trans: + xchk_trans_cancel(sc); + xchk_iunlock(sc, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL); + return error; +} + +/* + * Try to visit every inode in the filesystem for repairs. Move on if we can't + * grab an inode, since we're still making forward progress. + */ +static int +xrep_nlinks_iter( + struct xchk_nlink_ctrs *xnc, + struct xfs_inode **ipp) +{ + int error; + + do { + error = xchk_iscan_iter(&xnc->compare_iscan, ipp); + } while (error == -EBUSY); + + return error; +} + +/* Commit the new inode link counters. */ +int +xrep_nlinks( + struct xfs_scrub *sc) +{ + struct xchk_nlink_ctrs *xnc = sc->buf; + int error; + + /* + * We need ftype for an accurate count of the number of child + * subdirectory links. Child subdirectories with a back link (dotdot + * entry) but no forward link are unfixable, so we cannot repair the + * link count of the parent directory based on the back link count + * alone. Filesystems without ftype support are rare (old V4) so we + * just skip out here. + */ + if (!xfs_has_ftype(sc->mp)) + return -EOPNOTSUPP; + + /* + * Use the inobt to walk all allocated inodes to compare and fix the + * link counts. Retry iget every tenth of a second for up to 30 + * seconds -- even if repair misses a few inodes, we still try to fix + * as many of them as we can. + */ + xchk_iscan_start(sc, 30000, 100, &xnc->compare_iscan); + ASSERT(sc->ip == NULL); + + while ((error = xrep_nlinks_iter(xnc, &sc->ip)) == 1) { + /* + * 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_iter_finish(&xnc->compare_iscan); + xchk_iscan_teardown(&xnc->compare_iscan); + + return error; +} |