[PATCH 04/22] xfs: verify AGF blocks as they are read from disk

Dave Chinner
2012-11-06T05:11:54Z

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 <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
fs/xfs/xfs_alloc.c | 59 +++++++++++++++++++++++++++++-----------------------
1 file changed, 33 insertions(+), 26 deletions(-)

diff --git a/fs/xfs/xfs_alloc.c b/fs/xfs/xfs_alloc.c
index 34dcb7c..dbb32cc6 100644
--- a/fs/xfs/xfs_alloc.c
+++ b/fs/xfs/xfs_alloc.c
@@ -2091,6 +2091,38 @@ 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) &&
+ 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 +2134,19 @@ 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);