[PATCH 10/30] xfs: create helpers to scrub a metadata btree

["Darrick J. Wong" <darrick.wong@oracle.com>]

From: Darrick J. Wong <darrick.wong@oracle.com>

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

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/Makefile      |    1 
 fs/xfs/scrub/btree.c |  114 +++++++++++++++++++++++++++++++++++
 fs/xfs/scrub/btree.h |   57 +++++++++++++++++
 fs/xfs/scrub/trace.c |   17 +++++
 fs/xfs/scrub/trace.h |  163 ++++++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 352 insertions(+)
 create mode 100644 fs/xfs/scrub/btree.c
 create mode 100644 fs/xfs/scrub/btree.h


diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
index ca14595..5888b9f 100644
--- a/fs/xfs/Makefile
+++ b/fs/xfs/Makefile
@@ -146,6 +146,7 @@ ifeq ($(CONFIG_XFS_ONLINE_SCRUB),y)
 
 xfs-y				+= $(addprefix scrub/, \
 				   trace.o \
+				   btree.o \
 				   common.o \
 				   scrub.o \
 				   )
diff --git a/fs/xfs/scrub/btree.c b/fs/xfs/scrub/btree.c
new file mode 100644
index 0000000..28539081
--- /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;
+}
diff --git a/fs/xfs/scrub/btree.h b/fs/xfs/scrub/btree.h
new file mode 100644
index 0000000..4de825a6
--- /dev/null
+++ b/fs/xfs/scrub/btree.h
@@ -0,0 +1,57 @@
+/*
+ * 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.
+ */
+#ifndef __XFS_SCRUB_BTREE_H__
+#define __XFS_SCRUB_BTREE_H__
+
+/* btree scrub */
+
+/* Check for btree operation errors. */
+bool xfs_scrub_btree_process_error(struct xfs_scrub_context *sc,
+		struct xfs_btree_cur *cur, int level, int *error);
+
+/* Check for btree corruption. */
+void xfs_scrub_btree_set_corrupt(struct xfs_scrub_context *sc,
+		struct xfs_btree_cur *cur, int level);
+
+struct xfs_scrub_btree;
+typedef int (*xfs_scrub_btree_rec_fn)(
+	struct xfs_scrub_btree	*bs,
+	union xfs_btree_rec	*rec);
+
+struct xfs_scrub_btree {
+	/* caller-provided scrub state */
+	struct xfs_scrub_context	*sc;
+	struct xfs_btree_cur		*cur;
+	xfs_scrub_btree_rec_fn		scrub_rec;
+	struct xfs_owner_info		*oinfo;
+	void				*private;
+
+	/* internal scrub state */
+	union xfs_btree_rec		lastrec;
+	bool				firstrec;
+	union xfs_btree_key		lastkey[XFS_BTREE_MAXLEVELS];
+	bool				firstkey[XFS_BTREE_MAXLEVELS];
+	struct list_head		to_check;
+};
+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);
+
+#endif /* __XFS_SCRUB_BTREE_H__ */
diff --git a/fs/xfs/scrub/trace.c b/fs/xfs/scrub/trace.c
index 88b5ccb..472080e 100644
--- a/fs/xfs/scrub/trace.c
+++ b/fs/xfs/scrub/trace.c
@@ -30,10 +30,27 @@
 #include "xfs_inode.h"
 #include "xfs_btree.h"
 #include "xfs_trans.h"
+#include "xfs_bit.h"
 #include "scrub/xfs_scrub.h"
 #include "scrub/scrub.h"
 #include "scrub/common.h"
 
+/* Figure out which block the btree cursor was pointing to. */
+static inline xfs_fsblock_t
+xfs_scrub_btree_cur_fsbno(
+	struct xfs_btree_cur		*cur,
+	int				level)
+{
+	if (level < cur->bc_nlevels && cur->bc_bufs[level])
+		return XFS_DADDR_TO_FSB(cur->bc_mp, cur->bc_bufs[level]->b_bn);
+	else if (level == cur->bc_nlevels - 1 &&
+		 cur->bc_flags & XFS_BTREE_LONG_PTRS)
+		return XFS_INO_TO_FSB(cur->bc_mp, cur->bc_private.b.ip->i_ino);
+	else if (!(cur->bc_flags & XFS_BTREE_LONG_PTRS))
+		return XFS_AGB_TO_FSB(cur->bc_mp, cur->bc_private.a.agno, 0);
+	return NULLFSBLOCK;
+}
+
 /*
  * We include this last to have the helpers above available for the trace
  * event implementations.
diff --git a/fs/xfs/scrub/trace.h b/fs/xfs/scrub/trace.h
index d970659..147ea0b 100644
--- a/fs/xfs/scrub/trace.h
+++ b/fs/xfs/scrub/trace.h
@@ -283,6 +283,169 @@ TRACE_EVENT(xfs_scrub_incomplete,
 		  __entry->ret_ip)
 );
 
+TRACE_EVENT(xfs_scrub_btree_op_error,
+	TP_PROTO(struct xfs_scrub_context *sc, struct xfs_btree_cur *cur,
+		 int level, int error, void *ret_ip),
+	TP_ARGS(sc, cur, level, error, ret_ip),
+	TP_STRUCT__entry(
+		__field(dev_t, dev)
+		__field(unsigned int, type)
+		__field(xfs_btnum_t, btnum)
+		__field(int, level)
+		__field(xfs_agnumber_t, agno)
+		__field(xfs_agblock_t, bno)
+		__field(int, ptr);
+		__field(int, error)
+		__field(void *, ret_ip)
+	),
+	TP_fast_assign(
+		xfs_fsblock_t fsbno = xfs_scrub_btree_cur_fsbno(cur, level);
+
+		__entry->dev = sc->mp->m_super->s_dev;
+		__entry->type = sc->sm->sm_type;
+		__entry->btnum = cur->bc_btnum;
+		__entry->level = level;
+		__entry->agno = XFS_FSB_TO_AGNO(cur->bc_mp, fsbno);
+		__entry->bno = XFS_FSB_TO_AGBNO(cur->bc_mp, fsbno);
+		__entry->ptr = cur->bc_ptrs[level];
+		__entry->error = error;
+		__entry->ret_ip = ret_ip;
+	),
+	TP_printk("dev %d:%d type %u btnum %d level %d ptr %d agno %u agbno %u error %d ret_ip %pF",
+		  MAJOR(__entry->dev), MINOR(__entry->dev),
+		  __entry->type,
+		  __entry->btnum,
+		  __entry->level,
+		  __entry->ptr,
+		  __entry->agno,
+		  __entry->bno,
+		  __entry->error,
+		  __entry->ret_ip)
+);
+
+TRACE_EVENT(xfs_scrub_ifork_btree_op_error,
+	TP_PROTO(struct xfs_scrub_context *sc, struct xfs_btree_cur *cur,
+		 int level, int error, void *ret_ip),
+	TP_ARGS(sc, cur, level, error, ret_ip),
+	TP_STRUCT__entry(
+		__field(dev_t, dev)
+		__field(xfs_ino_t, ino)
+		__field(int, whichfork)
+		__field(unsigned int, type)
+		__field(xfs_btnum_t, btnum)
+		__field(int, level)
+		__field(int, ptr)
+		__field(xfs_agnumber_t, agno)
+		__field(xfs_agblock_t, bno)
+		__field(int, error)
+		__field(void *, ret_ip)
+	),
+	TP_fast_assign(
+		xfs_fsblock_t fsbno = xfs_scrub_btree_cur_fsbno(cur, level);
+		__entry->dev = sc->mp->m_super->s_dev;
+		__entry->ino = sc->ip->i_ino;
+		__entry->whichfork = cur->bc_private.b.whichfork;
+		__entry->type = sc->sm->sm_type;
+		__entry->btnum = cur->bc_btnum;
+		__entry->level = level;
+		__entry->ptr = cur->bc_ptrs[level];
+		__entry->agno = XFS_FSB_TO_AGNO(cur->bc_mp, fsbno);
+		__entry->bno = XFS_FSB_TO_AGBNO(cur->bc_mp, fsbno);
+		__entry->error = error;
+		__entry->ret_ip = ret_ip;
+	),
+	TP_printk("dev %d:%d ino %llu fork %d type %u btnum %d level %d ptr %d agno %u agbno %u error %d ret_ip %pF",
+		  MAJOR(__entry->dev), MINOR(__entry->dev),
+		  __entry->ino,
+		  __entry->whichfork,
+		  __entry->type,
+		  __entry->btnum,
+		  __entry->level,
+		  __entry->ptr,
+		  __entry->agno,
+		  __entry->bno,
+		  __entry->error,
+		  __entry->ret_ip)
+);
+
+TRACE_EVENT(xfs_scrub_btree_error,
+	TP_PROTO(struct xfs_scrub_context *sc, struct xfs_btree_cur *cur,
+		 int level, void *ret_ip),
+	TP_ARGS(sc, cur, level, ret_ip),
+	TP_STRUCT__entry(
+		__field(dev_t, dev)
+		__field(unsigned int, type)
+		__field(xfs_btnum_t, btnum)
+		__field(int, level)
+		__field(xfs_agnumber_t, agno)
+		__field(xfs_agblock_t, bno)
+		__field(int, ptr);
+		__field(void *, ret_ip)
+	),
+	TP_fast_assign(
+		xfs_fsblock_t fsbno = xfs_scrub_btree_cur_fsbno(cur, level);
+		__entry->dev = sc->mp->m_super->s_dev;
+		__entry->type = sc->sm->sm_type;
+		__entry->btnum = cur->bc_btnum;
+		__entry->level = level;
+		__entry->agno = XFS_FSB_TO_AGNO(cur->bc_mp, fsbno);
+		__entry->bno = XFS_FSB_TO_AGBNO(cur->bc_mp, fsbno);
+		__entry->ptr = cur->bc_ptrs[level];
+		__entry->ret_ip = ret_ip;
+	),
+	TP_printk("dev %d:%d type %u btnum %d level %d ptr %d agno %u agbno %u ret_ip %pF",
+		  MAJOR(__entry->dev), MINOR(__entry->dev),
+		  __entry->type,
+		  __entry->btnum,
+		  __entry->level,
+		  __entry->ptr,
+		  __entry->agno,
+		  __entry->bno,
+		  __entry->ret_ip)
+);
+
+TRACE_EVENT(xfs_scrub_ifork_btree_error,
+	TP_PROTO(struct xfs_scrub_context *sc, struct xfs_btree_cur *cur,
+		 int level, void *ret_ip),
+	TP_ARGS(sc, cur, level, ret_ip),
+	TP_STRUCT__entry(
+		__field(dev_t, dev)
+		__field(xfs_ino_t, ino)
+		__field(int, whichfork)
+		__field(unsigned int, type)
+		__field(xfs_btnum_t, btnum)
+		__field(int, level)
+		__field(xfs_agnumber_t, agno)
+		__field(xfs_agblock_t, bno)
+		__field(int, ptr);
+		__field(void *, ret_ip)
+	),
+	TP_fast_assign(
+		xfs_fsblock_t fsbno = xfs_scrub_btree_cur_fsbno(cur, level);
+		__entry->dev = sc->mp->m_super->s_dev;
+		__entry->ino = sc->ip->i_ino;
+		__entry->whichfork = cur->bc_private.b.whichfork;
+		__entry->type = sc->sm->sm_type;
+		__entry->btnum = cur->bc_btnum;
+		__entry->level = level;
+		__entry->agno = XFS_FSB_TO_AGNO(cur->bc_mp, fsbno);
+		__entry->bno = XFS_FSB_TO_AGBNO(cur->bc_mp, fsbno);
+		__entry->ptr = cur->bc_ptrs[level];
+		__entry->ret_ip = ret_ip;
+	),
+	TP_printk("dev %d:%d ino %llu fork %d type %u btnum %d level %d ptr %d agno %u agbno %u ret_ip %pF",
+		  MAJOR(__entry->dev), MINOR(__entry->dev),
+		  __entry->ino,
+		  __entry->whichfork,
+		  __entry->type,
+		  __entry->btnum,
+		  __entry->level,
+		  __entry->ptr,
+		  __entry->agno,
+		  __entry->bno,
+		  __entry->ret_ip)
+);
+
 #endif /* _TRACE_XFS_SCRUB_TRACE_H */
 
 #undef TRACE_INCLUDE_PATH