xfs: verify dir2 block format buffers

Add a dir2 block format read verifier. To fully verify every block
when read, call xfs_dir2_data_check() on them. Change
xfs_dir2_data_check() to do runtime checking, convert ASSERT()
checks to XFS_WANT_CORRUPTED_RETURN(), which will trigger an ASSERT
failure on debug kernels, but on production kernels will dump an
error to dmesg and return EFSCORRUPTED to the caller.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Phil White <pwhite@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

1 files changed, 21 insertions, 1 deletions

diff --git a/fs/xfs/xfs_dir2_block.c b/fs/xfs/xfs_dir2_block.c
index 25ce409487be..57351b868861 100644
--- a/fs/xfs/xfs_dir2_block.c
+++ b/fs/xfs/xfs_dir2_block.c
@@ -56,6 +56,26 @@ xfs_dir_startup(void)
         xfs_dir_hash_dotdot = xfs_da_hashname((unsigned char *)"..", 2);
 }
 
+static void
+xfs_dir2_block_verify(
+        struct xfs_buf          *bp)
+{
+        struct xfs_mount        *mp = bp->b_target->bt_mount;
+        struct xfs_dir2_data_hdr *hdr = bp->b_addr;
+        int                     block_ok = 0;
+
+        block_ok = hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC);
+        block_ok = block_ok && __xfs_dir2_data_check(NULL, bp) == 0;
+
+        if (!block_ok) {
+                XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, hdr);
+                xfs_buf_ioerror(bp, EFSCORRUPTED);
+        }
+
+        bp->b_iodone = NULL;
+        xfs_buf_ioend(bp, 0);
+}
+
 static int
 xfs_dir2_block_read(
         struct xfs_trans        *tp,
@@ -65,7 +85,7 @@ xfs_dir2_block_read(
         struct xfs_mount        *mp = dp->i_mount;
 
         return xfs_da_read_buf(tp, dp, mp->m_dirdatablk, -1, bpp,
-                                        XFS_DATA_FORK, NULL);
+                                        XFS_DATA_FORK, xfs_dir2_block_verify);
 }
 
 static void