xfs: add a function to deal with corrupt buffers post-verifiers

Add a helper function to get rid of buffers that we have decided are
corrupt after the verifiers have run.  This function is intended to
handle metadata checks that can't happen in the verifiers, such as
inter-block relationship checking.  Note that we now mark the buffer
stale so that it will not end up on any LRU and will be purged on
release.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

fs/xfs/xfs_buf.c

@@ -1573,6 +1573,28 @@ xfs_buf_zero(
 	}
 }
 
+/*
+ * Log a message about and stale a buffer that a caller has decided is corrupt.
+ *
+ * This function should be called for the kinds of metadata corruption that
+ * cannot be detect from a verifier, such as incorrect inter-block relationship
+ * data.  Do /not/ call this function from a verifier function.
+ *
+ * The buffer must be XBF_DONE prior to the call.  Afterwards, the buffer will
+ * be marked stale, but b_error will not be set.  The caller is responsible for
+ * releasing the buffer or fixing it.
+ */
+void
+__xfs_buf_mark_corrupt(
+	struct xfs_buf		*bp,
+	xfs_failaddr_t		fa)
+{
+	ASSERT(bp->b_flags & XBF_DONE);
+
+	xfs_buf_corruption_error(bp);
+	xfs_buf_stale(bp);
+}
+
 /*
  *	Handling of buffer targets (buftargs).
  */