text: // 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_btree.h"
  #include "xfs_alloc.h"
  #include "xfs_rmap.h"
  #include "scrub/scrub.h"
  #include "scrub/common.h"
  #include "scrub/btree.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_ag.agno;
  	xfs_agblock_t		bno;
  	xfs_extlen_t		len;
  
  	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 0;
  }
  
  /* Scrub the freespace btrees for some AG. */
  STATIC int
  xchk_allocbt(
  	struct xfs_scrub	*sc,
  	xfs_btnum_t		which)
  {
  	struct xfs_btree_cur	*cur;
  
  	cur = which == XFS_BTNUM_BNO ? sc->sa.bno_cur : sc->sa.cnt_cur;
  	return xchk_btree(sc, cur, xchk_allocbt_rec, &XFS_RMAP_OINFO_AG, 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);
  }
  