v4.19.13 snapshot.
diff --git a/fs/xfs/scrub/alloc.c b/fs/xfs/scrub/alloc.c
new file mode 100644
index 0000000..376bcb5
--- /dev/null
+++ b/fs/xfs/scrub/alloc.c
@@ -0,0 +1,168 @@
+// 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_alloc.h"
+#include "xfs_rmap.h"
+#include "scrub/xfs_scrub.h"
+#include "scrub/scrub.h"
+#include "scrub/common.h"
+#include "scrub/btree.h"
+#include "scrub/trace.h"
+
+/*
+ * Set us up to scrub free space btrees.
+ */
+int
+xchk_setup_ag_allocbt(
+ struct xfs_scrub *sc,
+ struct xfs_inode *ip)
+{
+ return xchk_setup_ag_btree(sc, ip, false);
+}
+
+/* Free space btree scrubber. */
+/*
+ * Ensure there's a corresponding cntbt/bnobt record matching this
+ * bnobt/cntbt record, respectively.
+ */
+STATIC void
+xchk_allocbt_xref_other(
+ struct xfs_scrub *sc,
+ xfs_agblock_t agbno,
+ xfs_extlen_t len)
+{
+ struct xfs_btree_cur **pcur;
+ xfs_agblock_t fbno;
+ xfs_extlen_t flen;
+ int has_otherrec;
+ int error;
+
+ if (sc->sm->sm_type == XFS_SCRUB_TYPE_BNOBT)
+ pcur = &sc->sa.cnt_cur;
+ else
+ pcur = &sc->sa.bno_cur;
+ if (!*pcur || xchk_skip_xref(sc->sm))
+ return;
+
+ error = xfs_alloc_lookup_le(*pcur, agbno, len, &has_otherrec);
+ if (!xchk_should_check_xref(sc, &error, pcur))
+ return;
+ if (!has_otherrec) {
+ xchk_btree_xref_set_corrupt(sc, *pcur, 0);
+ return;
+ }
+
+ error = xfs_alloc_get_rec(*pcur, &fbno, &flen, &has_otherrec);
+ if (!xchk_should_check_xref(sc, &error, pcur))
+ return;
+ if (!has_otherrec) {
+ xchk_btree_xref_set_corrupt(sc, *pcur, 0);
+ return;
+ }
+
+ if (fbno != agbno || flen != len)
+ xchk_btree_xref_set_corrupt(sc, *pcur, 0);
+}
+
+/* Cross-reference with the other btrees. */
+STATIC void
+xchk_allocbt_xref(
+ struct xfs_scrub *sc,
+ xfs_agblock_t agbno,
+ xfs_extlen_t len)
+{
+ if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
+ return;
+
+ xchk_allocbt_xref_other(sc, agbno, len);
+ xchk_xref_is_not_inode_chunk(sc, agbno, len);
+ xchk_xref_has_no_owner(sc, agbno, len);
+ xchk_xref_is_not_shared(sc, agbno, len);
+}
+
+/* Scrub a bnobt/cntbt record. */
+STATIC int
+xchk_allocbt_rec(
+ struct xchk_btree *bs,
+ union xfs_btree_rec *rec)
+{
+ struct xfs_mount *mp = bs->cur->bc_mp;
+ xfs_agnumber_t agno = bs->cur->bc_private.a.agno;
+ xfs_agblock_t bno;
+ xfs_extlen_t len;
+ int error = 0;
+
+ bno = be32_to_cpu(rec->alloc.ar_startblock);
+ len = be32_to_cpu(rec->alloc.ar_blockcount);
+
+ if (bno + len <= bno ||
+ !xfs_verify_agbno(mp, agno, bno) ||
+ !xfs_verify_agbno(mp, agno, bno + len - 1))
+ xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
+
+ xchk_allocbt_xref(bs->sc, bno, len);
+
+ return error;
+}
+
+/* Scrub the freespace btrees for some AG. */
+STATIC int
+xchk_allocbt(
+ struct xfs_scrub *sc,
+ xfs_btnum_t which)
+{
+ struct xfs_owner_info oinfo;
+ struct xfs_btree_cur *cur;
+
+ xfs_rmap_ag_owner(&oinfo, XFS_RMAP_OWN_AG);
+ cur = which == XFS_BTNUM_BNO ? sc->sa.bno_cur : sc->sa.cnt_cur;
+ return xchk_btree(sc, cur, xchk_allocbt_rec, &oinfo, NULL);
+}
+
+int
+xchk_bnobt(
+ struct xfs_scrub *sc)
+{
+ return xchk_allocbt(sc, XFS_BTNUM_BNO);
+}
+
+int
+xchk_cntbt(
+ struct xfs_scrub *sc)
+{
+ return xchk_allocbt(sc, XFS_BTNUM_CNT);
+}
+
+/* xref check that the extent is not free */
+void
+xchk_xref_is_used_space(
+ struct xfs_scrub *sc,
+ xfs_agblock_t agbno,
+ xfs_extlen_t len)
+{
+ bool is_freesp;
+ int error;
+
+ if (!sc->sa.bno_cur || xchk_skip_xref(sc->sm))
+ return;
+
+ error = xfs_alloc_has_record(sc->sa.bno_cur, agbno, len, &is_freesp);
+ if (!xchk_should_check_xref(sc, &error, &sc->sa.bno_cur))
+ return;
+ if (is_freesp)
+ xchk_btree_xref_set_corrupt(sc, sc->sa.bno_cur, 0);
+}