v4.19.13 snapshot.
diff --git a/fs/xfs/scrub/common.c b/fs/xfs/scrub/common.c
new file mode 100644
index 0000000..346b02a
--- /dev/null
+++ b/fs/xfs/scrub/common.c
@@ -0,0 +1,886 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2017 Oracle. All Rights Reserved.
+ * Author: Darrick J. Wong <darrick.wong@oracle.com>
+ */
+#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_defer.h"
+#include "xfs_btree.h"
+#include "xfs_bit.h"
+#include "xfs_log_format.h"
+#include "xfs_trans.h"
+#include "xfs_sb.h"
+#include "xfs_inode.h"
+#include "xfs_icache.h"
+#include "xfs_itable.h"
+#include "xfs_alloc.h"
+#include "xfs_alloc_btree.h"
+#include "xfs_bmap.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_ialloc.h"
+#include "xfs_ialloc_btree.h"
+#include "xfs_refcount.h"
+#include "xfs_refcount_btree.h"
+#include "xfs_rmap.h"
+#include "xfs_rmap_btree.h"
+#include "xfs_log.h"
+#include "xfs_trans_priv.h"
+#include "xfs_attr.h"
+#include "xfs_reflink.h"
+#include "scrub/xfs_scrub.h"
+#include "scrub/scrub.h"
+#include "scrub/common.h"
+#include "scrub/trace.h"
+#include "scrub/btree.h"
+#include "scrub/repair.h"
+
+/* Common code for the metadata scrubbers. */
+
+/*
+ * Handling operational errors.
+ *
+ * The *_process_error() family of functions are used to process error return
+ * codes from functions called as part of a scrub operation.
+ *
+ * If there's no error, we return true to tell the caller that it's ok
+ * to move on to the next check in its list.
+ *
+ * For non-verifier errors (e.g. ENOMEM) we return false to tell the
+ * caller that something bad happened, and we preserve *error so that
+ * the caller can return the *error up the stack to userspace.
+ *
+ * Verifier errors (EFSBADCRC/EFSCORRUPTED) are recorded by setting
+ * OFLAG_CORRUPT in sm_flags and the *error is cleared. In other words,
+ * we track verifier errors (and failed scrub checks) via OFLAG_CORRUPT,
+ * not via return codes. We return false to tell the caller that
+ * something bad happened. Since the error has been cleared, the caller
+ * will (presumably) return that zero and scrubbing will move on to
+ * whatever's next.
+ *
+ * ftrace can be used to record the precise metadata location and the
+ * approximate code location of the failed operation.
+ */
+
+/* Check for operational errors. */
+static bool
+__xchk_process_error(
+ struct xfs_scrub *sc,
+ xfs_agnumber_t agno,
+ xfs_agblock_t bno,
+ int *error,
+ __u32 errflag,
+ void *ret_ip)
+{
+ switch (*error) {
+ case 0:
+ return true;
+ case -EDEADLOCK:
+ /* Used to restart an op with deadlock avoidance. */
+ trace_xchk_deadlock_retry(sc->ip, sc->sm, *error);
+ break;
+ case -EFSBADCRC:
+ case -EFSCORRUPTED:
+ /* Note the badness but don't abort. */
+ sc->sm->sm_flags |= errflag;
+ *error = 0;
+ /* fall through */
+ default:
+ trace_xchk_op_error(sc, agno, bno, *error,
+ ret_ip);
+ break;
+ }
+ return false;
+}
+
+bool
+xchk_process_error(
+ struct xfs_scrub *sc,
+ xfs_agnumber_t agno,
+ xfs_agblock_t bno,
+ int *error)
+{
+ return __xchk_process_error(sc, agno, bno, error,
+ XFS_SCRUB_OFLAG_CORRUPT, __return_address);
+}
+
+bool
+xchk_xref_process_error(
+ struct xfs_scrub *sc,
+ xfs_agnumber_t agno,
+ xfs_agblock_t bno,
+ int *error)
+{
+ return __xchk_process_error(sc, agno, bno, error,
+ XFS_SCRUB_OFLAG_XFAIL, __return_address);
+}
+
+/* Check for operational errors for a file offset. */
+static bool
+__xchk_fblock_process_error(
+ struct xfs_scrub *sc,
+ int whichfork,
+ xfs_fileoff_t offset,
+ int *error,
+ __u32 errflag,
+ void *ret_ip)
+{
+ switch (*error) {
+ case 0:
+ return true;
+ case -EDEADLOCK:
+ /* Used to restart an op with deadlock avoidance. */
+ trace_xchk_deadlock_retry(sc->ip, sc->sm, *error);
+ break;
+ case -EFSBADCRC:
+ case -EFSCORRUPTED:
+ /* Note the badness but don't abort. */
+ sc->sm->sm_flags |= errflag;
+ *error = 0;
+ /* fall through */
+ default:
+ trace_xchk_file_op_error(sc, whichfork, offset, *error,
+ ret_ip);
+ break;
+ }
+ return false;
+}
+
+bool
+xchk_fblock_process_error(
+ struct xfs_scrub *sc,
+ int whichfork,
+ xfs_fileoff_t offset,
+ int *error)
+{
+ return __xchk_fblock_process_error(sc, whichfork, offset, error,
+ XFS_SCRUB_OFLAG_CORRUPT, __return_address);
+}
+
+bool
+xchk_fblock_xref_process_error(
+ struct xfs_scrub *sc,
+ int whichfork,
+ xfs_fileoff_t offset,
+ int *error)
+{
+ return __xchk_fblock_process_error(sc, whichfork, offset, error,
+ XFS_SCRUB_OFLAG_XFAIL, __return_address);
+}
+
+/*
+ * Handling scrub corruption/optimization/warning checks.
+ *
+ * The *_set_{corrupt,preen,warning}() family of functions are used to
+ * record the presence of metadata that is incorrect (corrupt), could be
+ * optimized somehow (preen), or should be flagged for administrative
+ * review but is not incorrect (warn).
+ *
+ * ftrace can be used to record the precise metadata location and
+ * approximate code location of the failed check.
+ */
+
+/* Record a block which could be optimized. */
+void
+xchk_block_set_preen(
+ struct xfs_scrub *sc,
+ struct xfs_buf *bp)
+{
+ sc->sm->sm_flags |= XFS_SCRUB_OFLAG_PREEN;
+ trace_xchk_block_preen(sc, bp->b_bn, __return_address);
+}
+
+/*
+ * Record an inode which could be optimized. The trace data will
+ * include the block given by bp if bp is given; otherwise it will use
+ * the block location of the inode record itself.
+ */
+void
+xchk_ino_set_preen(
+ struct xfs_scrub *sc,
+ xfs_ino_t ino)
+{
+ sc->sm->sm_flags |= XFS_SCRUB_OFLAG_PREEN;
+ trace_xchk_ino_preen(sc, ino, __return_address);
+}
+
+/* Record a corrupt block. */
+void
+xchk_block_set_corrupt(
+ struct xfs_scrub *sc,
+ struct xfs_buf *bp)
+{
+ sc->sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT;
+ trace_xchk_block_error(sc, bp->b_bn, __return_address);
+}
+
+/* Record a corruption while cross-referencing. */
+void
+xchk_block_xref_set_corrupt(
+ struct xfs_scrub *sc,
+ struct xfs_buf *bp)
+{
+ sc->sm->sm_flags |= XFS_SCRUB_OFLAG_XCORRUPT;
+ trace_xchk_block_error(sc, bp->b_bn, __return_address);
+}
+
+/*
+ * Record a corrupt inode. The trace data will include the block given
+ * by bp if bp is given; otherwise it will use the block location of the
+ * inode record itself.
+ */
+void
+xchk_ino_set_corrupt(
+ struct xfs_scrub *sc,
+ xfs_ino_t ino)
+{
+ sc->sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT;
+ trace_xchk_ino_error(sc, ino, __return_address);
+}
+
+/* Record a corruption while cross-referencing with an inode. */
+void
+xchk_ino_xref_set_corrupt(
+ struct xfs_scrub *sc,
+ xfs_ino_t ino)
+{
+ sc->sm->sm_flags |= XFS_SCRUB_OFLAG_XCORRUPT;
+ trace_xchk_ino_error(sc, ino, __return_address);
+}
+
+/* Record corruption in a block indexed by a file fork. */
+void
+xchk_fblock_set_corrupt(
+ struct xfs_scrub *sc,
+ int whichfork,
+ xfs_fileoff_t offset)
+{
+ sc->sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT;
+ trace_xchk_fblock_error(sc, whichfork, offset, __return_address);
+}
+
+/* Record a corruption while cross-referencing a fork block. */
+void
+xchk_fblock_xref_set_corrupt(
+ struct xfs_scrub *sc,
+ int whichfork,
+ xfs_fileoff_t offset)
+{
+ sc->sm->sm_flags |= XFS_SCRUB_OFLAG_XCORRUPT;
+ trace_xchk_fblock_error(sc, whichfork, offset, __return_address);
+}
+
+/*
+ * Warn about inodes that need administrative review but is not
+ * incorrect.
+ */
+void
+xchk_ino_set_warning(
+ struct xfs_scrub *sc,
+ xfs_ino_t ino)
+{
+ sc->sm->sm_flags |= XFS_SCRUB_OFLAG_WARNING;
+ trace_xchk_ino_warning(sc, ino, __return_address);
+}
+
+/* Warn about a block indexed by a file fork that needs review. */
+void
+xchk_fblock_set_warning(
+ struct xfs_scrub *sc,
+ int whichfork,
+ xfs_fileoff_t offset)
+{
+ sc->sm->sm_flags |= XFS_SCRUB_OFLAG_WARNING;
+ trace_xchk_fblock_warning(sc, whichfork, offset, __return_address);
+}
+
+/* Signal an incomplete scrub. */
+void
+xchk_set_incomplete(
+ struct xfs_scrub *sc)
+{
+ sc->sm->sm_flags |= XFS_SCRUB_OFLAG_INCOMPLETE;
+ trace_xchk_incomplete(sc, __return_address);
+}
+
+/*
+ * rmap scrubbing -- compute the number of blocks with a given owner,
+ * at least according to the reverse mapping data.
+ */
+
+struct xchk_rmap_ownedby_info {
+ struct xfs_owner_info *oinfo;
+ xfs_filblks_t *blocks;
+};
+
+STATIC int
+xchk_count_rmap_ownedby_irec(
+ struct xfs_btree_cur *cur,
+ struct xfs_rmap_irec *rec,
+ void *priv)
+{
+ struct xchk_rmap_ownedby_info *sroi = priv;
+ bool irec_attr;
+ bool oinfo_attr;
+
+ irec_attr = rec->rm_flags & XFS_RMAP_ATTR_FORK;
+ oinfo_attr = sroi->oinfo->oi_flags & XFS_OWNER_INFO_ATTR_FORK;
+
+ if (rec->rm_owner != sroi->oinfo->oi_owner)
+ return 0;
+
+ if (XFS_RMAP_NON_INODE_OWNER(rec->rm_owner) || irec_attr == oinfo_attr)
+ (*sroi->blocks) += rec->rm_blockcount;
+
+ return 0;
+}
+
+/*
+ * Calculate the number of blocks the rmap thinks are owned by something.
+ * The caller should pass us an rmapbt cursor.
+ */
+int
+xchk_count_rmap_ownedby_ag(
+ struct xfs_scrub *sc,
+ struct xfs_btree_cur *cur,
+ struct xfs_owner_info *oinfo,
+ xfs_filblks_t *blocks)
+{
+ struct xchk_rmap_ownedby_info sroi;
+
+ sroi.oinfo = oinfo;
+ *blocks = 0;
+ sroi.blocks = blocks;
+
+ return xfs_rmap_query_all(cur, xchk_count_rmap_ownedby_irec,
+ &sroi);
+}
+
+/*
+ * AG scrubbing
+ *
+ * These helpers facilitate locking an allocation group's header
+ * buffers, setting up cursors for all btrees that are present, and
+ * cleaning everything up once we're through.
+ */
+
+/* Decide if we want to return an AG header read failure. */
+static inline bool
+want_ag_read_header_failure(
+ struct xfs_scrub *sc,
+ unsigned int type)
+{
+ /* Return all AG header read failures when scanning btrees. */
+ if (sc->sm->sm_type != XFS_SCRUB_TYPE_AGF &&
+ sc->sm->sm_type != XFS_SCRUB_TYPE_AGFL &&
+ sc->sm->sm_type != XFS_SCRUB_TYPE_AGI)
+ return true;
+ /*
+ * If we're scanning a given type of AG header, we only want to
+ * see read failures from that specific header. We'd like the
+ * other headers to cross-check them, but this isn't required.
+ */
+ if (sc->sm->sm_type == type)
+ return true;
+ return false;
+}
+
+/*
+ * Grab all the headers for an AG.
+ *
+ * The headers should be released by xchk_ag_free, but as a fail
+ * safe we attach all the buffers we grab to the scrub transaction so
+ * they'll all be freed when we cancel it.
+ */
+int
+xchk_ag_read_headers(
+ struct xfs_scrub *sc,
+ xfs_agnumber_t agno,
+ struct xfs_buf **agi,
+ struct xfs_buf **agf,
+ struct xfs_buf **agfl)
+{
+ struct xfs_mount *mp = sc->mp;
+ int error;
+
+ error = xfs_ialloc_read_agi(mp, sc->tp, agno, agi);
+ if (error && want_ag_read_header_failure(sc, XFS_SCRUB_TYPE_AGI))
+ goto out;
+
+ error = xfs_alloc_read_agf(mp, sc->tp, agno, 0, agf);
+ if (error && want_ag_read_header_failure(sc, XFS_SCRUB_TYPE_AGF))
+ goto out;
+
+ error = xfs_alloc_read_agfl(mp, sc->tp, agno, agfl);
+ if (error && want_ag_read_header_failure(sc, XFS_SCRUB_TYPE_AGFL))
+ goto out;
+ error = 0;
+out:
+ return error;
+}
+
+/* Release all the AG btree cursors. */
+void
+xchk_ag_btcur_free(
+ struct xchk_ag *sa)
+{
+ if (sa->refc_cur)
+ xfs_btree_del_cursor(sa->refc_cur, XFS_BTREE_ERROR);
+ if (sa->rmap_cur)
+ xfs_btree_del_cursor(sa->rmap_cur, XFS_BTREE_ERROR);
+ if (sa->fino_cur)
+ xfs_btree_del_cursor(sa->fino_cur, XFS_BTREE_ERROR);
+ if (sa->ino_cur)
+ xfs_btree_del_cursor(sa->ino_cur, XFS_BTREE_ERROR);
+ if (sa->cnt_cur)
+ xfs_btree_del_cursor(sa->cnt_cur, XFS_BTREE_ERROR);
+ if (sa->bno_cur)
+ xfs_btree_del_cursor(sa->bno_cur, XFS_BTREE_ERROR);
+
+ sa->refc_cur = NULL;
+ sa->rmap_cur = NULL;
+ sa->fino_cur = NULL;
+ sa->ino_cur = NULL;
+ sa->bno_cur = NULL;
+ sa->cnt_cur = NULL;
+}
+
+/* Initialize all the btree cursors for an AG. */
+int
+xchk_ag_btcur_init(
+ struct xfs_scrub *sc,
+ struct xchk_ag *sa)
+{
+ struct xfs_mount *mp = sc->mp;
+ xfs_agnumber_t agno = sa->agno;
+
+ if (sa->agf_bp) {
+ /* Set up a bnobt cursor for cross-referencing. */
+ sa->bno_cur = xfs_allocbt_init_cursor(mp, sc->tp, sa->agf_bp,
+ agno, XFS_BTNUM_BNO);
+ if (!sa->bno_cur)
+ goto err;
+
+ /* Set up a cntbt cursor for cross-referencing. */
+ sa->cnt_cur = xfs_allocbt_init_cursor(mp, sc->tp, sa->agf_bp,
+ agno, XFS_BTNUM_CNT);
+ if (!sa->cnt_cur)
+ goto err;
+ }
+
+ /* Set up a inobt cursor for cross-referencing. */
+ if (sa->agi_bp) {
+ sa->ino_cur = xfs_inobt_init_cursor(mp, sc->tp, sa->agi_bp,
+ agno, XFS_BTNUM_INO);
+ if (!sa->ino_cur)
+ goto err;
+ }
+
+ /* Set up a finobt cursor for cross-referencing. */
+ if (sa->agi_bp && xfs_sb_version_hasfinobt(&mp->m_sb)) {
+ sa->fino_cur = xfs_inobt_init_cursor(mp, sc->tp, sa->agi_bp,
+ agno, XFS_BTNUM_FINO);
+ if (!sa->fino_cur)
+ goto err;
+ }
+
+ /* Set up a rmapbt cursor for cross-referencing. */
+ if (sa->agf_bp && xfs_sb_version_hasrmapbt(&mp->m_sb)) {
+ sa->rmap_cur = xfs_rmapbt_init_cursor(mp, sc->tp, sa->agf_bp,
+ agno);
+ if (!sa->rmap_cur)
+ goto err;
+ }
+
+ /* Set up a refcountbt cursor for cross-referencing. */
+ if (sa->agf_bp && xfs_sb_version_hasreflink(&mp->m_sb)) {
+ sa->refc_cur = xfs_refcountbt_init_cursor(mp, sc->tp,
+ sa->agf_bp, agno);
+ if (!sa->refc_cur)
+ goto err;
+ }
+
+ return 0;
+err:
+ return -ENOMEM;
+}
+
+/* Release the AG header context and btree cursors. */
+void
+xchk_ag_free(
+ struct xfs_scrub *sc,
+ struct xchk_ag *sa)
+{
+ xchk_ag_btcur_free(sa);
+ if (sa->agfl_bp) {
+ xfs_trans_brelse(sc->tp, sa->agfl_bp);
+ sa->agfl_bp = NULL;
+ }
+ if (sa->agf_bp) {
+ xfs_trans_brelse(sc->tp, sa->agf_bp);
+ sa->agf_bp = NULL;
+ }
+ if (sa->agi_bp) {
+ xfs_trans_brelse(sc->tp, sa->agi_bp);
+ sa->agi_bp = NULL;
+ }
+ if (sa->pag) {
+ xfs_perag_put(sa->pag);
+ sa->pag = NULL;
+ }
+ sa->agno = NULLAGNUMBER;
+}
+
+/*
+ * For scrub, grab the AGI and the AGF headers, in that order. Locking
+ * order requires us to get the AGI before the AGF. We use the
+ * transaction to avoid deadlocking on crosslinked metadata buffers;
+ * either the caller passes one in (bmap scrub) or we have to create a
+ * transaction ourselves.
+ */
+int
+xchk_ag_init(
+ struct xfs_scrub *sc,
+ xfs_agnumber_t agno,
+ struct xchk_ag *sa)
+{
+ int error;
+
+ sa->agno = agno;
+ error = xchk_ag_read_headers(sc, agno, &sa->agi_bp,
+ &sa->agf_bp, &sa->agfl_bp);
+ if (error)
+ return error;
+
+ return xchk_ag_btcur_init(sc, sa);
+}
+
+/*
+ * Grab the per-ag structure if we haven't already gotten it. Teardown of the
+ * xchk_ag will release it for us.
+ */
+void
+xchk_perag_get(
+ struct xfs_mount *mp,
+ struct xchk_ag *sa)
+{
+ if (!sa->pag)
+ sa->pag = xfs_perag_get(mp, sa->agno);
+}
+
+/* Per-scrubber setup functions */
+
+/*
+ * Grab an empty transaction so that we can re-grab locked buffers if
+ * one of our btrees turns out to be cyclic.
+ *
+ * If we're going to repair something, we need to ask for the largest possible
+ * log reservation so that we can handle the worst case scenario for metadata
+ * updates while rebuilding a metadata item. We also need to reserve as many
+ * blocks in the head transaction as we think we're going to need to rebuild
+ * the metadata object.
+ */
+int
+xchk_trans_alloc(
+ struct xfs_scrub *sc,
+ uint resblks)
+{
+ if (sc->sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR)
+ return xfs_trans_alloc(sc->mp, &M_RES(sc->mp)->tr_itruncate,
+ resblks, 0, 0, &sc->tp);
+
+ return xfs_trans_alloc_empty(sc->mp, &sc->tp);
+}
+
+/* Set us up with a transaction and an empty context. */
+int
+xchk_setup_fs(
+ struct xfs_scrub *sc,
+ struct xfs_inode *ip)
+{
+ uint resblks;
+
+ resblks = xrep_calc_ag_resblks(sc);
+ return xchk_trans_alloc(sc, resblks);
+}
+
+/* Set us up with AG headers and btree cursors. */
+int
+xchk_setup_ag_btree(
+ struct xfs_scrub *sc,
+ struct xfs_inode *ip,
+ bool force_log)
+{
+ struct xfs_mount *mp = sc->mp;
+ int error;
+
+ /*
+ * If the caller asks us to checkpont the log, do so. This
+ * expensive operation should be performed infrequently and only
+ * as a last resort. Any caller that sets force_log should
+ * document why they need to do so.
+ */
+ if (force_log) {
+ error = xchk_checkpoint_log(mp);
+ if (error)
+ return error;
+ }
+
+ error = xchk_setup_fs(sc, ip);
+ if (error)
+ return error;
+
+ return xchk_ag_init(sc, sc->sm->sm_agno, &sc->sa);
+}
+
+/* Push everything out of the log onto disk. */
+int
+xchk_checkpoint_log(
+ struct xfs_mount *mp)
+{
+ int error;
+
+ error = xfs_log_force(mp, XFS_LOG_SYNC);
+ if (error)
+ return error;
+ xfs_ail_push_all_sync(mp->m_ail);
+ return 0;
+}
+
+/*
+ * Given an inode and the scrub control structure, grab either the
+ * inode referenced in the control structure or the inode passed in.
+ * The inode is not locked.
+ */
+int
+xchk_get_inode(
+ struct xfs_scrub *sc,
+ struct xfs_inode *ip_in)
+{
+ struct xfs_imap imap;
+ struct xfs_mount *mp = sc->mp;
+ struct xfs_inode *ip = NULL;
+ int error;
+
+ /* We want to scan the inode we already had opened. */
+ if (sc->sm->sm_ino == 0 || sc->sm->sm_ino == ip_in->i_ino) {
+ sc->ip = ip_in;
+ return 0;
+ }
+
+ /* Look up the inode, see if the generation number matches. */
+ if (xfs_internal_inum(mp, sc->sm->sm_ino))
+ return -ENOENT;
+ error = xfs_iget(mp, NULL, sc->sm->sm_ino,
+ XFS_IGET_UNTRUSTED | XFS_IGET_DONTCACHE, 0, &ip);
+ switch (error) {
+ case -ENOENT:
+ /* Inode doesn't exist, just bail out. */
+ return error;
+ case 0:
+ /* Got an inode, continue. */
+ break;
+ case -EINVAL:
+ /*
+ * -EINVAL with IGET_UNTRUSTED could mean one of several
+ * things: userspace gave us an inode number that doesn't
+ * correspond to fs space, or doesn't have an inobt entry;
+ * or it could simply mean that the inode buffer failed the
+ * read verifiers.
+ *
+ * Try just the inode mapping lookup -- if it succeeds, then
+ * the inode buffer verifier failed and something needs fixing.
+ * Otherwise, we really couldn't find it so tell userspace
+ * that it no longer exists.
+ */
+ error = xfs_imap(sc->mp, sc->tp, sc->sm->sm_ino, &imap,
+ XFS_IGET_UNTRUSTED | XFS_IGET_DONTCACHE);
+ if (error)
+ return -ENOENT;
+ error = -EFSCORRUPTED;
+ /* fall through */
+ default:
+ trace_xchk_op_error(sc,
+ XFS_INO_TO_AGNO(mp, sc->sm->sm_ino),
+ XFS_INO_TO_AGBNO(mp, sc->sm->sm_ino),
+ error, __return_address);
+ return error;
+ }
+ if (VFS_I(ip)->i_generation != sc->sm->sm_gen) {
+ xfs_irele(ip);
+ return -ENOENT;
+ }
+
+ sc->ip = ip;
+ return 0;
+}
+
+/* Set us up to scrub a file's contents. */
+int
+xchk_setup_inode_contents(
+ struct xfs_scrub *sc,
+ struct xfs_inode *ip,
+ unsigned int resblks)
+{
+ int error;
+
+ error = xchk_get_inode(sc, ip);
+ if (error)
+ return error;
+
+ /* Got the inode, lock it and we're ready to go. */
+ sc->ilock_flags = XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL;
+ xfs_ilock(sc->ip, sc->ilock_flags);
+ error = xchk_trans_alloc(sc, resblks);
+ if (error)
+ goto out;
+ sc->ilock_flags |= XFS_ILOCK_EXCL;
+ xfs_ilock(sc->ip, XFS_ILOCK_EXCL);
+
+out:
+ /* scrub teardown will unlock and release the inode for us */
+ return error;
+}
+
+/*
+ * Predicate that decides if we need to evaluate the cross-reference check.
+ * If there was an error accessing the cross-reference btree, just delete
+ * the cursor and skip the check.
+ */
+bool
+xchk_should_check_xref(
+ struct xfs_scrub *sc,
+ int *error,
+ struct xfs_btree_cur **curpp)
+{
+ /* No point in xref if we already know we're corrupt. */
+ if (xchk_skip_xref(sc->sm))
+ return false;
+
+ if (*error == 0)
+ return true;
+
+ if (curpp) {
+ /* If we've already given up on xref, just bail out. */
+ if (!*curpp)
+ return false;
+
+ /* xref error, delete cursor and bail out. */
+ xfs_btree_del_cursor(*curpp, XFS_BTREE_ERROR);
+ *curpp = NULL;
+ }
+
+ sc->sm->sm_flags |= XFS_SCRUB_OFLAG_XFAIL;
+ trace_xchk_xref_error(sc, *error, __return_address);
+
+ /*
+ * Errors encountered during cross-referencing with another
+ * data structure should not cause this scrubber to abort.
+ */
+ *error = 0;
+ return false;
+}
+
+/* Run the structure verifiers on in-memory buffers to detect bad memory. */
+void
+xchk_buffer_recheck(
+ struct xfs_scrub *sc,
+ struct xfs_buf *bp)
+{
+ xfs_failaddr_t fa;
+
+ if (bp->b_ops == NULL) {
+ xchk_block_set_corrupt(sc, bp);
+ return;
+ }
+ if (bp->b_ops->verify_struct == NULL) {
+ xchk_set_incomplete(sc);
+ return;
+ }
+ fa = bp->b_ops->verify_struct(bp);
+ if (!fa)
+ return;
+ sc->sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT;
+ trace_xchk_block_error(sc, bp->b_bn, fa);
+}
+
+/*
+ * Scrub the attr/data forks of a metadata inode. The metadata inode must be
+ * pointed to by sc->ip and the ILOCK must be held.
+ */
+int
+xchk_metadata_inode_forks(
+ struct xfs_scrub *sc)
+{
+ __u32 smtype;
+ bool shared;
+ int error;
+
+ if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
+ return 0;
+
+ /* Metadata inodes don't live on the rt device. */
+ if (sc->ip->i_d.di_flags & XFS_DIFLAG_REALTIME) {
+ xchk_ino_set_corrupt(sc, sc->ip->i_ino);
+ return 0;
+ }
+
+ /* They should never participate in reflink. */
+ if (xfs_is_reflink_inode(sc->ip)) {
+ xchk_ino_set_corrupt(sc, sc->ip->i_ino);
+ return 0;
+ }
+
+ /* They also should never have extended attributes. */
+ if (xfs_inode_hasattr(sc->ip)) {
+ xchk_ino_set_corrupt(sc, sc->ip->i_ino);
+ return 0;
+ }
+
+ /* Invoke the data fork scrubber. */
+ smtype = sc->sm->sm_type;
+ sc->sm->sm_type = XFS_SCRUB_TYPE_BMBTD;
+ error = xchk_bmap_data(sc);
+ sc->sm->sm_type = smtype;
+ if (error || (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT))
+ return error;
+
+ /* Look for incorrect shared blocks. */
+ if (xfs_sb_version_hasreflink(&sc->mp->m_sb)) {
+ error = xfs_reflink_inode_has_shared_extents(sc->tp, sc->ip,
+ &shared);
+ if (!xchk_fblock_process_error(sc, XFS_DATA_FORK, 0,
+ &error))
+ return error;
+ if (shared)
+ xchk_ino_set_corrupt(sc, sc->ip->i_ino);
+ }
+
+ return error;
+}
+
+/*
+ * Try to lock an inode in violation of the usual locking order rules. For
+ * example, trying to get the IOLOCK while in transaction context, or just
+ * plain breaking AG-order or inode-order inode locking rules. Either way,
+ * the only way to avoid an ABBA deadlock is to use trylock and back off if
+ * we can't.
+ */
+int
+xchk_ilock_inverted(
+ struct xfs_inode *ip,
+ uint lock_mode)
+{
+ int i;
+
+ for (i = 0; i < 20; i++) {
+ if (xfs_ilock_nowait(ip, lock_mode))
+ return 0;
+ delay(1);
+ }
+ return -EDEADLOCK;
+}