xfs: scrub the realtime group superblock

Enable scrubbing of realtime group superblocks.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

fs/xfs/Makefile

@@ -191,6 +191,7 @@ xfs-y				+= $(addprefix scrub/, \
 xfs-$(CONFIG_XFS_ONLINE_SCRUB_STATS) += scrub/stats.o
 
 xfs-$(CONFIG_XFS_RT)		+= $(addprefix scrub/, \
+				   rgsuper.o \
 				   rtbitmap.o \
 				   rtsummary.o \
 				   )

fs/xfs/libxfs/xfs_fs.h

@@ -736,9 +736,10 @@ struct xfs_scrub_metadata {
 #define XFS_SCRUB_TYPE_HEALTHY	27	/* everything checked out ok */
 #define XFS_SCRUB_TYPE_DIRTREE	28	/* directory tree structure */
 #define XFS_SCRUB_TYPE_METAPATH	29	/* metadata directory tree paths */
+#define XFS_SCRUB_TYPE_RGSUPER	30	/* realtime superblock */
 
 /* Number of scrub subcommands. */
-#define XFS_SCRUB_TYPE_NR	30
+#define XFS_SCRUB_TYPE_NR	31
 
 /*
  * This special type code only applies to the vectored scrub implementation.

fs/xfs/scrub/common.h

@@ -79,9 +79,11 @@ int xchk_setup_metapath(struct xfs_scrub *sc);
 #ifdef CONFIG_XFS_RT
 int xchk_setup_rtbitmap(struct xfs_scrub *sc);
 int xchk_setup_rtsummary(struct xfs_scrub *sc);
+int xchk_setup_rgsuperblock(struct xfs_scrub *sc);
 #else
 # define xchk_setup_rtbitmap		xchk_setup_nothing
 # define xchk_setup_rtsummary		xchk_setup_nothing
+# define xchk_setup_rgsuperblock	xchk_setup_nothing
 #endif
 #ifdef CONFIG_XFS_QUOTA
 int xchk_ino_dqattach(struct xfs_scrub *sc);

fs/xfs/scrub/health.c

@@ -111,6 +111,7 @@ static const struct xchk_health_map type_to_health_flag[XFS_SCRUB_TYPE_NR] = {
 	[XFS_SCRUB_TYPE_NLINKS]		= { XHG_FS,  XFS_SICK_FS_NLINKS },
 	[XFS_SCRUB_TYPE_DIRTREE]	= { XHG_INO, XFS_SICK_INO_DIRTREE },
 	[XFS_SCRUB_TYPE_METAPATH]	= { XHG_FS,  XFS_SICK_FS_METAPATH },
+	[XFS_SCRUB_TYPE_RGSUPER]	= { XHG_RTGROUP, XFS_SICK_RG_SUPER },
 };
 
 /* Return the health status mask for this scrub type. */

fs/xfs/scrub/rgsuper.c

@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2022-2024 Oracle.  All Rights Reserved.
+ * Author: Darrick J. Wong <djwong@kernel.org>
+ */
+#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_rtgroup.h"
+#include "scrub/scrub.h"
+#include "scrub/common.h"
+
+/* Set us up with a transaction and an empty context. */
+int
+xchk_setup_rgsuperblock(
+	struct xfs_scrub	*sc)
+{
+	return xchk_trans_alloc(sc, 0);
+}
+
+/* Cross-reference with the other rt metadata. */
+STATIC void
+xchk_rgsuperblock_xref(
+	struct xfs_scrub	*sc)
+{
+	if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
+		return;
+
+	xchk_xref_is_used_rt_space(sc, xfs_rgbno_to_rtb(sc->sr.rtg, 0), 1);
+}
+
+int
+xchk_rgsuperblock(
+	struct xfs_scrub	*sc)
+{
+	xfs_rgnumber_t		rgno = sc->sm->sm_agno;
+	int			error;
+
+	/*
+	 * Only rtgroup 0 has a superblock.  We may someday want to use higher
+	 * rgno for other functions, similar to what we do with the primary
+	 * super scrub function.
+	 */
+	if (rgno != 0)
+		return -ENOENT;
+
+	/*
+	 * Grab an active reference to the rtgroup structure.  If we can't get
+	 * it, we're racing with something that's tearing down the group, so
+	 * signal that the group no longer exists.  Take the rtbitmap in shared
+	 * mode so that the group can't change while we're doing things.
+	 */
+	error = xchk_rtgroup_init_existing(sc, rgno, &sc->sr);
+	if (!xchk_xref_process_error(sc, 0, 0, &error))
+		return error;
+
+	xchk_rtgroup_lock(&sc->sr, XFS_RTGLOCK_BITMAP_SHARED);
+
+	/*
+	 * Since we already validated the rt superblock at mount time, we don't
+	 * need to check its contents again.  All we need is to cross-reference.
+	 */
+	xchk_rgsuperblock_xref(sc);
+	return 0;
+}

fs/xfs/scrub/scrub.c

@@ -451,6 +451,13 @@ static const struct xchk_meta_ops meta_scrub_ops[] = {
 		.has	= xfs_has_metadir,
 		.repair	= xrep_metapath,
 	},
+	[XFS_SCRUB_TYPE_RGSUPER] = {	/* realtime group superblock */
+		.type	= ST_RTGROUP,
+		.setup	= xchk_setup_rgsuperblock,
+		.scrub	= xchk_rgsuperblock,
+		.has	= xfs_has_rtsb,
+		.repair = xrep_notsupported,
+	},
 };
 
 static int

fs/xfs/scrub/scrub.h

@@ -273,9 +273,11 @@ int xchk_metapath(struct xfs_scrub *sc);
 #ifdef CONFIG_XFS_RT
 int xchk_rtbitmap(struct xfs_scrub *sc);
 int xchk_rtsummary(struct xfs_scrub *sc);
+int xchk_rgsuperblock(struct xfs_scrub *sc);
 #else
 # define xchk_rtbitmap		xchk_nothing
 # define xchk_rtsummary		xchk_nothing
+# define xchk_rgsuperblock	xchk_nothing
 #endif
 #ifdef CONFIG_XFS_QUOTA
 int xchk_quota(struct xfs_scrub *sc);

fs/xfs/scrub/stats.c

@@ -81,6 +81,7 @@ static const char *name_map[XFS_SCRUB_TYPE_NR] = {
 	[XFS_SCRUB_TYPE_NLINKS]		= "nlinks",
 	[XFS_SCRUB_TYPE_DIRTREE]	= "dirtree",
 	[XFS_SCRUB_TYPE_METAPATH]	= "metapath",
+	[XFS_SCRUB_TYPE_RGSUPER]	= "rgsuper",
 };
 
 /* Format the scrub stats into a text buffer, similar to pcp style. */

fs/xfs/scrub/trace.h

@@ -71,6 +71,7 @@ TRACE_DEFINE_ENUM(XFS_SCRUB_TYPE_HEALTHY);
 TRACE_DEFINE_ENUM(XFS_SCRUB_TYPE_DIRTREE);
 TRACE_DEFINE_ENUM(XFS_SCRUB_TYPE_BARRIER);
 TRACE_DEFINE_ENUM(XFS_SCRUB_TYPE_METAPATH);
+TRACE_DEFINE_ENUM(XFS_SCRUB_TYPE_RGSUPER);
 
 #define XFS_SCRUB_TYPE_STRINGS \
 	{ XFS_SCRUB_TYPE_PROBE,		"probe" }, \
@@ -103,7 +104,8 @@ TRACE_DEFINE_ENUM(XFS_SCRUB_TYPE_METAPATH);
 	{ XFS_SCRUB_TYPE_HEALTHY,	"healthy" }, \
 	{ XFS_SCRUB_TYPE_DIRTREE,	"dirtree" }, \
 	{ XFS_SCRUB_TYPE_BARRIER,	"barrier" }, \
-	{ XFS_SCRUB_TYPE_METAPATH,	"metapath" }
+	{ XFS_SCRUB_TYPE_METAPATH,	"metapath" }, \
+	{ XFS_SCRUB_TYPE_RGSUPER,	"rgsuper" }
 
 #define XFS_SCRUB_FLAG_STRINGS \
 	{ XFS_SCRUB_IFLAG_REPAIR,		"repair" }, \