xfs: scrub free space btrees

Check the extent records free space btrees to ensure that the values
look sane.

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

fs/xfs/Makefile

@@ -144,6 +144,7 @@ ifeq ($(CONFIG_XFS_ONLINE_SCRUB),y)
 xfs-y				+= $(addprefix scrub/, \
 				   trace.o \
 				   agheader.o \
+				   alloc.o \
 				   btree.o \
 				   common.o \
 				   scrub.o \

fs/xfs/libxfs/xfs_fs.h

@@ -488,9 +488,11 @@ struct xfs_scrub_metadata {
 #define XFS_SCRUB_TYPE_AGF	2	/* AG free header */
 #define XFS_SCRUB_TYPE_AGFL	3	/* AG free list */
 #define XFS_SCRUB_TYPE_AGI	4	/* AG inode header */
+#define XFS_SCRUB_TYPE_BNOBT	5	/* freesp by block btree */
+#define XFS_SCRUB_TYPE_CNTBT	6	/* freesp by length btree */
 
 /* Number of scrub subcommands. */
-#define XFS_SCRUB_TYPE_NR	5
+#define XFS_SCRUB_TYPE_NR	7
 
 /* i: Repair this metadata. */
 #define XFS_SCRUB_IFLAG_REPAIR		(1 << 0)

fs/xfs/scrub/alloc.c

@@ -0,0 +1,102 @@
+/*
+ * 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_alloc.h"
+#include "xfs_rmap.h"
+#include "scrub/xfs_scrub.h"
+#include "scrub/scrub.h"
+#include "scrub/common.h"
+#include "scrub/btree.h"
+#include "scrub/trace.h"
+
+/*
+ * Set us up to scrub free space btrees.
+ */
+int
+xfs_scrub_setup_ag_allocbt(
+	struct xfs_scrub_context	*sc,
+	struct xfs_inode		*ip)
+{
+	return xfs_scrub_setup_ag_btree(sc, ip, false);
+}
+
+/* Free space btree scrubber. */
+
+/* Scrub a bnobt/cntbt record. */
+STATIC int
+xfs_scrub_allocbt_rec(
+	struct xfs_scrub_btree		*bs,
+	union xfs_btree_rec		*rec)
+{
+	struct xfs_mount		*mp = bs->cur->bc_mp;
+	xfs_agnumber_t			agno = bs->cur->bc_private.a.agno;
+	xfs_agblock_t			bno;
+	xfs_extlen_t			len;
+	int				error = 0;
+
+	bno = be32_to_cpu(rec->alloc.ar_startblock);
+	len = be32_to_cpu(rec->alloc.ar_blockcount);
+
+	if (bno + len <= bno ||
+	    !xfs_verify_agbno(mp, agno, bno) ||
+	    !xfs_verify_agbno(mp, agno, bno + len - 1))
+		xfs_scrub_btree_set_corrupt(bs->sc, bs->cur, 0);
+
+	return error;
+}
+
+/* Scrub the freespace btrees for some AG. */
+STATIC int
+xfs_scrub_allocbt(
+	struct xfs_scrub_context	*sc,
+	xfs_btnum_t			which)
+{
+	struct xfs_owner_info		oinfo;
+	struct xfs_btree_cur		*cur;
+
+	xfs_rmap_ag_owner(&oinfo, XFS_RMAP_OWN_AG);
+	cur = which == XFS_BTNUM_BNO ? sc->sa.bno_cur : sc->sa.cnt_cur;
+	return xfs_scrub_btree(sc, cur, xfs_scrub_allocbt_rec, &oinfo, NULL);
+}
+
+int
+xfs_scrub_bnobt(
+	struct xfs_scrub_context	*sc)
+{
+	return xfs_scrub_allocbt(sc, XFS_BTNUM_BNO);
+}
+
+int
+xfs_scrub_cntbt(
+	struct xfs_scrub_context	*sc)
+{
+	return xfs_scrub_allocbt(sc, XFS_BTNUM_CNT);
+}

fs/xfs/scrub/common.c

@@ -443,3 +443,19 @@ xfs_scrub_setup_fs(
 {
 	return xfs_scrub_trans_alloc(sc->sm, sc->mp, &sc->tp);
 }
+
+/* Set us up with AG headers and btree cursors. */
+int
+xfs_scrub_setup_ag_btree(
+	struct xfs_scrub_context	*sc,
+	struct xfs_inode		*ip,
+	bool				force_log)
+{
+	int				error;
+
+	error = xfs_scrub_setup_ag_header(sc, ip);
+	if (error)
+		return error;
+
+	return xfs_scrub_ag_init(sc, sc->sm->sm_agno, &sc->sa);
+}

fs/xfs/scrub/common.h

@@ -78,6 +78,9 @@ void xfs_scrub_set_incomplete(struct xfs_scrub_context *sc);
 int xfs_scrub_setup_fs(struct xfs_scrub_context *sc, struct xfs_inode *ip);
 int xfs_scrub_setup_ag_header(struct xfs_scrub_context *sc,
 			      struct xfs_inode *ip);
+int xfs_scrub_setup_ag_allocbt(struct xfs_scrub_context *sc,
+			       struct xfs_inode *ip);
+
 
 void xfs_scrub_ag_free(struct xfs_scrub_context *sc, struct xfs_scrub_ag *sa);
 int xfs_scrub_ag_init(struct xfs_scrub_context *sc, xfs_agnumber_t agno,
@@ -93,4 +96,7 @@ int xfs_scrub_walk_agfl(struct xfs_scrub_context *sc,
 				  void *),
 			void *priv);
 
+int xfs_scrub_setup_ag_btree(struct xfs_scrub_context *sc,
+			     struct xfs_inode *ip, bool force_log);
+
 #endif	/* __XFS_SCRUB_COMMON_H__ */

fs/xfs/scrub/scrub.c

@@ -174,6 +174,14 @@ static const struct xfs_scrub_meta_ops meta_scrub_ops[] = {
 		.setup	= xfs_scrub_setup_ag_header,
 		.scrub	= xfs_scrub_agi,
 	},
+	{ /* bnobt */
+		.setup	= xfs_scrub_setup_ag_allocbt,
+		.scrub	= xfs_scrub_bnobt,
+	},
+	{ /* cntbt */
+		.setup	= xfs_scrub_setup_ag_allocbt,
+		.scrub	= xfs_scrub_cntbt,
+	},
 };
 
 /* This isn't a stable feature, warn once per day. */

fs/xfs/scrub/scrub.h

@@ -71,5 +71,7 @@ int xfs_scrub_superblock(struct xfs_scrub_context *sc);
 int xfs_scrub_agf(struct xfs_scrub_context *sc);
 int xfs_scrub_agfl(struct xfs_scrub_context *sc);
 int xfs_scrub_agi(struct xfs_scrub_context *sc);
+int xfs_scrub_bnobt(struct xfs_scrub_context *sc);
+int xfs_scrub_cntbt(struct xfs_scrub_context *sc);
 
 #endif	/* __XFS_SCRUB_SCRUB_H__ */