[PATCH 17/55] xfs: scrub the backup superblocks

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

Ensure that the geometry presented in the backup superblocks matches
the primary superblock so that repair can recover the filesystem if
that primary gets corrupted.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/Makefile         |    1 
 fs/xfs/libxfs/xfs_fs.h  |    3 -
 fs/xfs/scrub/agheader.c |  198 +++++++++++++++++++++++++++++++++++++++++++++++
 fs/xfs/scrub/common.c   |    1 
 fs/xfs/scrub/common.h   |    6 +
 fs/xfs/xfs_trace.h      |    3 -
 6 files changed, 210 insertions(+), 2 deletions(-)
 create mode 100644 fs/xfs/scrub/agheader.c


diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
index 39bcf8a..ca7399a 100644
--- a/fs/xfs/Makefile
+++ b/fs/xfs/Makefile
@@ -104,6 +104,7 @@ xfs-y				+= xfs_aops.o \
 
 # online scrub/repair
 xfs-$(CONFIG_XFS_DEBUG)		+= $(addprefix scrub/, \
+				   agheader.o \
 				   btree.o \
 				   common.o \
 				   )
diff --git a/fs/xfs/libxfs/xfs_fs.h b/fs/xfs/libxfs/xfs_fs.h
index da3277a..6fb1cc6 100644
--- a/fs/xfs/libxfs/xfs_fs.h
+++ b/fs/xfs/libxfs/xfs_fs.h
@@ -575,7 +575,8 @@ struct xfs_scrub_metadata {
  * Metadata types and flags for scrub operation.
  */
 #define XFS_SCRUB_TYPE_TEST	0	/* dummy to test ioctl */
-#define XFS_SCRUB_TYPE_MAX	0
+#define XFS_SCRUB_TYPE_SB	1	/* superblock */
+#define XFS_SCRUB_TYPE_MAX	1
 
 #define XFS_SCRUB_FLAG_REPAIR	0x01	/* i: repair this metadata */
 #define XFS_SCRUB_FLAG_CORRUPT	0x02	/* o: needs repair */
diff --git a/fs/xfs/scrub/agheader.c b/fs/xfs/scrub/agheader.c
new file mode 100644
index 0000000..98031e3
--- /dev/null
+++ b/fs/xfs/scrub/agheader.c
@@ -0,0 +1,198 @@
+/*
+ * 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_trace.h"
+#include "xfs_sb.h"
+#include "xfs_inode.h"
+#include "scrub/common.h"
+
+/* Set us up to check an AG header. */
+int
+xfs_scrub_setup_ag(
+	struct xfs_scrub_context	*sc,
+	struct xfs_inode		*ip,
+	struct xfs_scrub_metadata	*sm,
+	bool				retry_deadlocked)
+{
+	struct xfs_mount		*mp = ip->i_mount;
+
+	if (sm->sm_agno >= mp->m_sb.sb_agcount)
+		return -EINVAL;
+	return xfs_scrub_setup(sc, ip, sm, retry_deadlocked);
+}
+
+/* Superblock */
+
+#define XFS_SCRUB_SB_CHECK(fs_ok) \
+	XFS_SCRUB_CHECK(sc, bp, "superblock", fs_ok)
+#define XFS_SCRUB_SB_PREEN(fs_ok) \
+	XFS_SCRUB_PREEN(sc, bp, "superblock", fs_ok)
+#define XFS_SCRUB_SB_OP_ERROR_GOTO(label) \
+	XFS_SCRUB_OP_ERROR_GOTO(sc, agno, 0, "superblock", &error, out)
+/* Scrub the filesystem superblock. */
+int
+xfs_scrub_superblock(
+	struct xfs_scrub_context	*sc)
+{
+	struct xfs_mount		*mp = sc->tp->t_mountp;
+	struct xfs_buf			*bp;
+	struct xfs_sb			sb;
+	xfs_agnumber_t			agno;
+	uint32_t			v2_ok;
+	int				error;
+
+	agno = sc->sm->sm_agno;
+
+	error = xfs_trans_read_buf(mp, sc->tp, mp->m_ddev_targp,
+		  XFS_AGB_TO_DADDR(mp, agno, XFS_SB_BLOCK(mp)),
+		  XFS_FSS_TO_BB(mp, 1), 0, &bp, &xfs_sb_buf_ops);
+	if (error) {
+		trace_xfs_scrub_block_error(mp, agno, XFS_SB_BLOCK(mp),
+				"superblock", "error != 0", __func__, __LINE__);
+		error = 0;
+		sc->sm->sm_flags |= XFS_SCRUB_FLAG_CORRUPT;
+		goto out;
+	}
+
+	/*
+	 * The in-core sb is a more up-to-date copy of AG 0's sb,
+	 * so there's no point in comparing the two.
+	 */
+	if (agno == 0)
+		goto out;
+
+	xfs_sb_from_disk(&sb, XFS_BUF_TO_SBP(bp));
+
+	/* Verify the geometries match. */
+#define XFS_SCRUB_SB_FIELD(fn) \
+		XFS_SCRUB_SB_CHECK(sb.sb_##fn == mp->m_sb.sb_##fn)
+#define XFS_PREEN_SB_FIELD(fn) \
+		XFS_SCRUB_SB_PREEN(sb.sb_##fn == mp->m_sb.sb_##fn)
+	XFS_SCRUB_SB_FIELD(blocksize);
+	XFS_SCRUB_SB_FIELD(dblocks);
+	XFS_SCRUB_SB_FIELD(rblocks);
+	XFS_SCRUB_SB_FIELD(rextents);
+	XFS_SCRUB_SB_PREEN(uuid_equal(&sb.sb_uuid, &mp->m_sb.sb_uuid));
+	XFS_SCRUB_SB_FIELD(logstart);
+	XFS_PREEN_SB_FIELD(rootino);
+	XFS_PREEN_SB_FIELD(rbmino);
+	XFS_PREEN_SB_FIELD(rsumino);
+	XFS_SCRUB_SB_FIELD(rextsize);
+	XFS_SCRUB_SB_FIELD(agblocks);
+	XFS_SCRUB_SB_FIELD(agcount);
+	XFS_SCRUB_SB_FIELD(rbmblocks);
+	XFS_SCRUB_SB_FIELD(logblocks);
+	XFS_SCRUB_SB_CHECK(!(sb.sb_versionnum & ~XFS_SB_VERSION_OKBITS));
+	XFS_SCRUB_SB_CHECK(XFS_SB_VERSION_NUM(&sb) ==
+			   XFS_SB_VERSION_NUM(&mp->m_sb));
+	XFS_SCRUB_SB_FIELD(sectsize);
+	XFS_SCRUB_SB_FIELD(inodesize);
+	XFS_SCRUB_SB_FIELD(inopblock);
+	XFS_SCRUB_SB_PREEN(memcmp(sb.sb_fname, mp->m_sb.sb_fname,
+			   sizeof(sb.sb_fname)) == 0);
+	XFS_SCRUB_SB_FIELD(blocklog);
+	XFS_SCRUB_SB_FIELD(sectlog);
+	XFS_SCRUB_SB_FIELD(inodelog);
+	XFS_SCRUB_SB_FIELD(inopblog);
+	XFS_SCRUB_SB_FIELD(agblklog);
+	XFS_SCRUB_SB_FIELD(rextslog);
+	XFS_PREEN_SB_FIELD(imax_pct);
+	XFS_PREEN_SB_FIELD(uquotino);
+	XFS_PREEN_SB_FIELD(gquotino);
+	XFS_SCRUB_SB_FIELD(shared_vn);
+	XFS_SCRUB_SB_FIELD(inoalignmt);
+	XFS_PREEN_SB_FIELD(unit);
+	XFS_PREEN_SB_FIELD(width);
+	XFS_SCRUB_SB_FIELD(dirblklog);
+	XFS_SCRUB_SB_FIELD(logsectlog);
+	XFS_SCRUB_SB_FIELD(logsectsize);
+	XFS_SCRUB_SB_FIELD(logsunit);
+	v2_ok = XFS_SB_VERSION2_OKBITS;
+	if (XFS_SB_VERSION_NUM(&sb) >= XFS_SB_VERSION_5)
+		v2_ok |= XFS_SB_VERSION2_CRCBIT;
+	XFS_SCRUB_SB_CHECK(!(sb.sb_features2 & ~v2_ok));
+	XFS_SCRUB_SB_PREEN(sb.sb_features2 == sb.sb_bad_features2);
+	XFS_SCRUB_SB_CHECK(!sb.sb_features2 ||
+			xfs_sb_version_hasmorebits(&mp->m_sb));
+	if (xfs_sb_version_hascrc(&mp->m_sb)) {
+		XFS_SCRUB_SB_CHECK(!xfs_sb_has_compat_feature(&sb,
+				XFS_SB_FEAT_COMPAT_UNKNOWN));
+		XFS_SCRUB_SB_CHECK(!xfs_sb_has_ro_compat_feature(&sb,
+				XFS_SB_FEAT_RO_COMPAT_UNKNOWN));
+		XFS_SCRUB_SB_CHECK(!xfs_sb_has_incompat_feature(&sb,
+				XFS_SB_FEAT_INCOMPAT_UNKNOWN));
+		XFS_SCRUB_SB_CHECK(!xfs_sb_has_incompat_log_feature(&sb,
+				XFS_SB_FEAT_INCOMPAT_LOG_UNKNOWN));
+		XFS_SCRUB_SB_FIELD(spino_align);
+		XFS_PREEN_SB_FIELD(pquotino);
+	}
+	if (xfs_sb_version_hasmetauuid(&mp->m_sb)) {
+		XFS_SCRUB_SB_CHECK(uuid_equal(&sb.sb_meta_uuid,
+					&mp->m_sb.sb_meta_uuid));
+		XFS_SCRUB_SB_CHECK(uuid_equal(&sb.sb_uuid,
+					&mp->m_sb.sb_uuid));
+	} else
+		XFS_SCRUB_SB_CHECK(uuid_equal(&sb.sb_uuid,
+					&mp->m_sb.sb_meta_uuid));
+#undef XFS_SCRUB_SB_FIELD
+
+#define XFS_SCRUB_SB_FEAT(fn) \
+		XFS_SCRUB_SB_CHECK(xfs_sb_version_has##fn(&sb) == \
+		xfs_sb_version_has##fn(&mp->m_sb))
+	XFS_SCRUB_SB_FEAT(align);
+	XFS_SCRUB_SB_FEAT(dalign);
+	XFS_SCRUB_SB_FEAT(logv2);
+	XFS_SCRUB_SB_FEAT(extflgbit);
+	XFS_SCRUB_SB_FEAT(sector);
+	XFS_SCRUB_SB_FEAT(asciici);
+	XFS_SCRUB_SB_FEAT(morebits);
+	XFS_SCRUB_SB_FEAT(lazysbcount);
+	XFS_SCRUB_SB_FEAT(crc);
+	XFS_SCRUB_SB_FEAT(_pquotino);
+	XFS_SCRUB_SB_FEAT(ftype);
+	XFS_SCRUB_SB_FEAT(finobt);
+	XFS_SCRUB_SB_FEAT(sparseinodes);
+	XFS_SCRUB_SB_FEAT(metauuid);
+	XFS_SCRUB_SB_FEAT(rmapbt);
+	XFS_SCRUB_SB_FEAT(reflink);
+#undef XFS_SCRUB_SB_FEAT
+
+#define XFS_SCRUB_SB_FEAT_PREEN(fn) \
+		XFS_SCRUB_SB_PREEN(xfs_sb_version_has##fn(&sb) == \
+		xfs_sb_version_has##fn(&mp->m_sb))
+	XFS_SCRUB_SB_FEAT_PREEN(attr);
+	XFS_SCRUB_SB_FEAT_PREEN(attr2);
+#undef XFS_SCRUB_SB_FEAT_PREEN
+
+out:
+	return error;
+}
+#undef XFS_SCRUB_SB_OP_ERROR_GOTO
+#undef XFS_SCRUB_SB_CHECK
diff --git a/fs/xfs/scrub/common.c b/fs/xfs/scrub/common.c
index c4dd16c..924079d 100644
--- a/fs/xfs/scrub/common.c
+++ b/fs/xfs/scrub/common.c
@@ -598,6 +598,7 @@ struct xfs_scrub_meta_fns {
 
 static const struct xfs_scrub_meta_fns meta_scrub_fns[] = {
 	{xfs_scrub_setup, xfs_scrub_dummy, NULL, NULL},
+	{xfs_scrub_setup_ag, xfs_scrub_superblock, NULL, NULL},
 };
 
 /* Dispatch metadata scrubbing. */
diff --git a/fs/xfs/scrub/common.h b/fs/xfs/scrub/common.h
index fc38f67..bd2896b 100644
--- a/fs/xfs/scrub/common.h
+++ b/fs/xfs/scrub/common.h
@@ -196,5 +196,11 @@ int xfs_scrub_ag_btcur_init(struct xfs_scrub_context *sc,
 int xfs_scrub_teardown(struct xfs_scrub_context *sc, int error);
 int xfs_scrub_setup(struct xfs_scrub_context *sc, struct xfs_inode *ip,
 		    struct xfs_scrub_metadata *sm, bool retry_deadlocked);
+int xfs_scrub_setup_ag(struct xfs_scrub_context *sc, struct xfs_inode *ip,
+		       struct xfs_scrub_metadata *sm, bool retry_deadlocked);
+
+/* Metadata scrubbers */
+
+int xfs_scrub_superblock(struct xfs_scrub_context *sc);
 
 #endif	/* __XFS_REPAIR_COMMON_H__ */
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 3e04690..ddfe15f 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -3353,7 +3353,8 @@ DEFINE_GETFSMAP_EVENT(xfs_getfsmap_mapping);
 
 /* scrub */
 #define XFS_SCRUB_TYPE_DESC \
-	{ XFS_SCRUB_TYPE_TEST,		"dummy" }
+	{ XFS_SCRUB_TYPE_TEST,		"dummy" }, \
+	{ XFS_SCRUB_TYPE_SB,		"superblock" }
 DECLARE_EVENT_CLASS(xfs_scrub_class,
 	TP_PROTO(struct xfs_inode *ip, int type, xfs_agnumber_t agno,
 		 xfs_ino_t inum, unsigned int gen, unsigned int flags,