From 5d5f527d13369d0047d52b7ac4ddee4f8c0ad173 Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Wed, 14 Nov 2012 17:44:56 +1100 Subject: [PATCH] xfs: verify AGF blocks as they are read from disk Add an AGF block verify callback function and pass it into the buffer read functions. This replaces the existing verification that is done after the read completes. Signed-off-by: Dave Chinner Reviewed-by: Christoph Hellwig Reviewed-by: Mark Tinguely Signed-off-by: Ben Myers --- fs/xfs/xfs_alloc.c | 68 ++++++++++++++++++++++++++++------------------ 1 file changed, 42 insertions(+), 26 deletions(-) diff --git a/fs/xfs/xfs_alloc.c b/fs/xfs/xfs_alloc.c index 21c3db08fd01..c9eb955a49c7 100644 --- a/fs/xfs/xfs_alloc.c +++ b/fs/xfs/xfs_alloc.c @@ -2091,6 +2091,47 @@ xfs_alloc_put_freelist( return 0; } +static void +xfs_agf_read_verify( + struct xfs_buf *bp) + { + struct xfs_mount *mp = bp->b_target->bt_mount; + struct xfs_agf *agf; + int agf_ok; + + agf = XFS_BUF_TO_AGF(bp); + + agf_ok = agf->agf_magicnum == cpu_to_be32(XFS_AGF_MAGIC) && + XFS_AGF_GOOD_VERSION(be32_to_cpu(agf->agf_versionnum)) && + be32_to_cpu(agf->agf_freeblks) <= be32_to_cpu(agf->agf_length) && + be32_to_cpu(agf->agf_flfirst) < XFS_AGFL_SIZE(mp) && + be32_to_cpu(agf->agf_fllast) < XFS_AGFL_SIZE(mp) && + be32_to_cpu(agf->agf_flcount) <= XFS_AGFL_SIZE(mp); + + /* + * during growfs operations, the perag is not fully initialised, + * so we can't use it for any useful checking. growfs ensures we can't + * use it by using uncached buffers that don't have the perag attached + * so we can detect and avoid this problem. + */ + if (bp->b_pag) + agf_ok = agf_ok && be32_to_cpu(agf->agf_seqno) == + bp->b_pag->pag_agno; + + if (xfs_sb_version_haslazysbcount(&mp->m_sb)) + agf_ok = agf_ok && be32_to_cpu(agf->agf_btreeblks) <= + be32_to_cpu(agf->agf_length); + + if (unlikely(XFS_TEST_ERROR(!agf_ok, mp, XFS_ERRTAG_ALLOC_READ_AGF, + XFS_RANDOM_ALLOC_READ_AGF))) { + XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, agf); + xfs_buf_ioerror(bp, EFSCORRUPTED); + } + + bp->b_iodone = NULL; + xfs_buf_ioend(bp, 0); +} + /* * Read in the allocation group header (free/alloc section). */ @@ -2102,44 +2143,19 @@ xfs_read_agf( int flags, /* XFS_BUF_ */ struct xfs_buf **bpp) /* buffer for the ag freelist header */ { - struct xfs_agf *agf; /* ag freelist header */ - int agf_ok; /* set if agf is consistent */ int error; ASSERT(agno != NULLAGNUMBER); error = xfs_trans_read_buf( mp, tp, mp->m_ddev_targp, XFS_AG_DADDR(mp, agno, XFS_AGF_DADDR(mp)), - XFS_FSS_TO_BB(mp, 1), flags, bpp, NULL); + XFS_FSS_TO_BB(mp, 1), flags, bpp, xfs_agf_read_verify); if (error) return error; if (!*bpp) return 0; ASSERT(!(*bpp)->b_error); - agf = XFS_BUF_TO_AGF(*bpp); - - /* - * Validate the magic number of the agf block. - */ - agf_ok = - agf->agf_magicnum == cpu_to_be32(XFS_AGF_MAGIC) && - XFS_AGF_GOOD_VERSION(be32_to_cpu(agf->agf_versionnum)) && - be32_to_cpu(agf->agf_freeblks) <= be32_to_cpu(agf->agf_length) && - be32_to_cpu(agf->agf_flfirst) < XFS_AGFL_SIZE(mp) && - be32_to_cpu(agf->agf_fllast) < XFS_AGFL_SIZE(mp) && - be32_to_cpu(agf->agf_flcount) <= XFS_AGFL_SIZE(mp) && - be32_to_cpu(agf->agf_seqno) == agno; - if (xfs_sb_version_haslazysbcount(&mp->m_sb)) - agf_ok = agf_ok && be32_to_cpu(agf->agf_btreeblks) <= - be32_to_cpu(agf->agf_length); - if (unlikely(XFS_TEST_ERROR(!agf_ok, mp, XFS_ERRTAG_ALLOC_READ_AGF, - XFS_RANDOM_ALLOC_READ_AGF))) { - XFS_CORRUPTION_ERROR("xfs_alloc_read_agf", - XFS_ERRLEVEL_LOW, mp, agf); - xfs_trans_brelse(tp, *bpp); - return XFS_ERROR(EFSCORRUPTED); - } xfs_buf_set_ref(*bpp, XFS_AGF_REF); return 0; }