xfs: create helpers to scrub a metadata btree

Create helper functions and tracepoints to deal with errors while
scrubbing a metadata btree.

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

1 files changed, 114 insertions, 0 deletions

diff --git a/fs/xfs/scrub/btree.c b/fs/xfs/scrub/btree.c
new file mode 100644
index 000000000000..28539081f604
--- /dev/null
+++ b/fs/xfs/scrub/btree.c
@@ -0,0 +1,114 @@
+/*
+ * Copyright (C) 2017 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <darrick.wong@oracle.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_shared.h"
+#include "xfs_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_mount.h"
+#include "xfs_defer.h"
+#include "xfs_btree.h"
+#include "xfs_bit.h"
+#include "xfs_log_format.h"
+#include "xfs_trans.h"
+#include "xfs_sb.h"
+#include "xfs_inode.h"
+#include "xfs_alloc.h"
+#include "scrub/scrub.h"
+#include "scrub/common.h"
+#include "scrub/btree.h"
+#include "scrub/trace.h"
+
+/* btree scrubbing */
+
+/*
+ * Check for btree operation errors.  See the section about handling
+ * operational errors in common.c.
+ */
+bool
+xfs_scrub_btree_process_error(
+	struct xfs_scrub_context	*sc,
+	struct xfs_btree_cur		*cur,
+	int				level,
+	int				*error)
+{
+	if (*error == 0)
+		return true;
+
+	switch (*error) {
+	case -EDEADLOCK:
+		/* Used to restart an op with deadlock avoidance. */
+		trace_xfs_scrub_deadlock_retry(sc->ip, sc->sm, *error);
+		break;
+	case -EFSBADCRC:
+	case -EFSCORRUPTED:
+		/* Note the badness but don't abort. */
+		sc->sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT;
+		*error = 0;
+		/* fall through */
+	default:
+		if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE)
+			trace_xfs_scrub_ifork_btree_op_error(sc, cur, level,
+					*error, __return_address);
+		else
+			trace_xfs_scrub_btree_op_error(sc, cur, level,
+					*error, __return_address);
+		break;
+	}
+	return false;
+}
+
+/* Record btree block corruption. */
+void
+xfs_scrub_btree_set_corrupt(
+	struct xfs_scrub_context	*sc,
+	struct xfs_btree_cur		*cur,
+	int				level)
+{
+	sc->sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT;
+
+	if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE)
+		trace_xfs_scrub_ifork_btree_error(sc, cur, level,
+				__return_address);
+	else
+		trace_xfs_scrub_btree_error(sc, cur, level,
+				__return_address);
+}
+
+/*
+ * Visit all nodes and leaves of a btree.  Check that all pointers and
+ * records are in order, that the keys reflect the records, and use a callback
+ * so that the caller can verify individual records.  The callback is the same
+ * as the one for xfs_btree_query_range, so therefore this function also
+ * returns XFS_BTREE_QUERY_RANGE_ABORT, zero, or a negative error code.
+ */
+int
+xfs_scrub_btree(
+	struct xfs_scrub_context	*sc,
+	struct xfs_btree_cur		*cur,
+	xfs_scrub_btree_rec_fn		scrub_fn,
+	struct xfs_owner_info		*oinfo,
+	void				*private)
+{
+	int				error = -EOPNOTSUPP;
+
+	xfs_scrub_btree_process_error(sc, cur, 0, &error);
+	return error;
+}