xfs: detect self referencing btree sibling pointers
To catch the obvious graph cycle problem and hence potential endless looping. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Dave Chinner <david@fromorbit.com>
This commit is contained in:
Dave Chinner
Dave Chinner
parent
a44a027a8b
commit
dc04db2aa7
@ -51,6 +51,52 @@ xfs_btree_magic(
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return magic;
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}
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static xfs_failaddr_t
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xfs_btree_check_lblock_siblings(
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struct xfs_mount *mp,
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struct xfs_btree_cur *cur,
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int level,
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xfs_fsblock_t fsb,
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xfs_fsblock_t sibling)
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{
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if (sibling == NULLFSBLOCK)
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return NULL;
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if (sibling == fsb)
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return __this_address;
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if (level >= 0) {
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if (!xfs_btree_check_lptr(cur, sibling, level + 1))
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return __this_address;
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} else {
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if (!xfs_verify_fsbno(mp, sibling))
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return __this_address;
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}
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return NULL;
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}
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static xfs_failaddr_t
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xfs_btree_check_sblock_siblings(
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struct xfs_mount *mp,
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struct xfs_btree_cur *cur,
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int level,
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xfs_agnumber_t agno,
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xfs_agblock_t agbno,
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xfs_agblock_t sibling)
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{
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if (sibling == NULLAGBLOCK)
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return NULL;
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if (sibling == agbno)
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return __this_address;
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if (level >= 0) {
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if (!xfs_btree_check_sptr(cur, sibling, level + 1))
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return __this_address;
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} else {
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if (!xfs_verify_agbno(mp, agno, sibling))
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return __this_address;
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}
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return NULL;
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}
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/*
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* Check a long btree block header. Return the address of the failing check,
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* or NULL if everything is ok.
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@ -65,6 +111,8 @@ __xfs_btree_check_lblock(
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struct xfs_mount *mp = cur->bc_mp;
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xfs_btnum_t btnum = cur->bc_btnum;
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int crc = xfs_has_crc(mp);
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xfs_failaddr_t fa;
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xfs_fsblock_t fsb = NULLFSBLOCK;
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if (crc) {
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if (!uuid_equal(&block->bb_u.l.bb_uuid, &mp->m_sb.sb_meta_uuid))
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@ -83,16 +131,16 @@ __xfs_btree_check_lblock(
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if (be16_to_cpu(block->bb_numrecs) >
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cur->bc_ops->get_maxrecs(cur, level))
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return __this_address;
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if (block->bb_u.l.bb_leftsib != cpu_to_be64(NULLFSBLOCK) &&
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!xfs_btree_check_lptr(cur, be64_to_cpu(block->bb_u.l.bb_leftsib),
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level + 1))
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return __this_address;
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if (block->bb_u.l.bb_rightsib != cpu_to_be64(NULLFSBLOCK) &&
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!xfs_btree_check_lptr(cur, be64_to_cpu(block->bb_u.l.bb_rightsib),
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level + 1))
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return __this_address;
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return NULL;
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if (bp)
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fsb = XFS_DADDR_TO_FSB(mp, xfs_buf_daddr(bp));
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fa = xfs_btree_check_lblock_siblings(mp, cur, level, fsb,
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be64_to_cpu(block->bb_u.l.bb_leftsib));
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if (!fa)
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fa = xfs_btree_check_lblock_siblings(mp, cur, level, fsb,
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be64_to_cpu(block->bb_u.l.bb_rightsib));
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return fa;
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}
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/* Check a long btree block header. */
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@ -130,6 +178,9 @@ __xfs_btree_check_sblock(
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struct xfs_mount *mp = cur->bc_mp;
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xfs_btnum_t btnum = cur->bc_btnum;
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int crc = xfs_has_crc(mp);
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xfs_failaddr_t fa;
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xfs_agblock_t agbno = NULLAGBLOCK;
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xfs_agnumber_t agno = NULLAGNUMBER;
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if (crc) {
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if (!uuid_equal(&block->bb_u.s.bb_uuid, &mp->m_sb.sb_meta_uuid))
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@ -146,16 +197,18 @@ __xfs_btree_check_sblock(
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if (be16_to_cpu(block->bb_numrecs) >
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cur->bc_ops->get_maxrecs(cur, level))
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return __this_address;
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if (block->bb_u.s.bb_leftsib != cpu_to_be32(NULLAGBLOCK) &&
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!xfs_btree_check_sptr(cur, be32_to_cpu(block->bb_u.s.bb_leftsib),
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level + 1))
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return __this_address;
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if (block->bb_u.s.bb_rightsib != cpu_to_be32(NULLAGBLOCK) &&
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!xfs_btree_check_sptr(cur, be32_to_cpu(block->bb_u.s.bb_rightsib),
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level + 1))
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return __this_address;
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return NULL;
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if (bp) {
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agbno = xfs_daddr_to_agbno(mp, xfs_buf_daddr(bp));
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agno = xfs_daddr_to_agno(mp, xfs_buf_daddr(bp));
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}
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fa = xfs_btree_check_sblock_siblings(mp, cur, level, agno, agbno,
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be32_to_cpu(block->bb_u.s.bb_leftsib));
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if (!fa)
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fa = xfs_btree_check_sblock_siblings(mp, cur, level, agno,
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agbno, be32_to_cpu(block->bb_u.s.bb_rightsib));
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return fa;
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}
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/* Check a short btree block header. */
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@ -4271,6 +4324,21 @@ xfs_btree_visit_block(
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if (xfs_btree_ptr_is_null(cur, &rptr))
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return -ENOENT;
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/*
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* We only visit blocks once in this walk, so we have to avoid the
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* internal xfs_btree_lookup_get_block() optimisation where it will
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* return the same block without checking if the right sibling points
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* back to us and creates a cyclic reference in the btree.
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*/
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if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
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if (be64_to_cpu(rptr.l) == XFS_DADDR_TO_FSB(cur->bc_mp,
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xfs_buf_daddr(bp)))
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return -EFSCORRUPTED;
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} else {
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if (be32_to_cpu(rptr.s) == xfs_daddr_to_agbno(cur->bc_mp,
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xfs_buf_daddr(bp)))
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return -EFSCORRUPTED;
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}
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return xfs_btree_lookup_get_block(cur, level, &rptr, &block);
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}
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@ -4445,20 +4513,21 @@ xfs_btree_lblock_verify(
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{
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struct xfs_mount *mp = bp->b_mount;
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struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
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xfs_fsblock_t fsb;
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xfs_failaddr_t fa;
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/* numrecs verification */
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if (be16_to_cpu(block->bb_numrecs) > max_recs)
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return __this_address;
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/* sibling pointer verification */
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if (block->bb_u.l.bb_leftsib != cpu_to_be64(NULLFSBLOCK) &&
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!xfs_verify_fsbno(mp, be64_to_cpu(block->bb_u.l.bb_leftsib)))
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return __this_address;
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if (block->bb_u.l.bb_rightsib != cpu_to_be64(NULLFSBLOCK) &&
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!xfs_verify_fsbno(mp, be64_to_cpu(block->bb_u.l.bb_rightsib)))
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return __this_address;
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return NULL;
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fsb = XFS_DADDR_TO_FSB(mp, xfs_buf_daddr(bp));
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fa = xfs_btree_check_lblock_siblings(mp, NULL, -1, fsb,
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be64_to_cpu(block->bb_u.l.bb_leftsib));
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if (!fa)
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fa = xfs_btree_check_lblock_siblings(mp, NULL, -1, fsb,
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be64_to_cpu(block->bb_u.l.bb_rightsib));
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return fa;
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}
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/**
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@ -4499,7 +4568,9 @@ xfs_btree_sblock_verify(
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{
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struct xfs_mount *mp = bp->b_mount;
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struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
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xfs_agblock_t agno;
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xfs_agnumber_t agno;
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xfs_agblock_t agbno;
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xfs_failaddr_t fa;
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/* numrecs verification */
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if (be16_to_cpu(block->bb_numrecs) > max_recs)
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@ -4507,14 +4578,13 @@ xfs_btree_sblock_verify(
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/* sibling pointer verification */
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agno = xfs_daddr_to_agno(mp, xfs_buf_daddr(bp));
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if (block->bb_u.s.bb_leftsib != cpu_to_be32(NULLAGBLOCK) &&
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!xfs_verify_agbno(mp, agno, be32_to_cpu(block->bb_u.s.bb_leftsib)))
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return __this_address;
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if (block->bb_u.s.bb_rightsib != cpu_to_be32(NULLAGBLOCK) &&
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!xfs_verify_agbno(mp, agno, be32_to_cpu(block->bb_u.s.bb_rightsib)))
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return __this_address;
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return NULL;
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agbno = xfs_daddr_to_agbno(mp, xfs_buf_daddr(bp));
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fa = xfs_btree_check_sblock_siblings(mp, NULL, -1, agno, agbno,
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be32_to_cpu(block->bb_u.s.bb_leftsib));
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if (!fa)
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fa = xfs_btree_check_sblock_siblings(mp, NULL, -1, agno, agbno,
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be32_to_cpu(block->bb_u.s.bb_rightsib));
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return fa;
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}
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/*
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