[PATCH 1/1] xfs: repair summary counters

Darrick J. Wong
2023-12-31T20:13:34Z

Use the same summary counter calculation infrastructure to generate new
values for the in-core summary counters. The difference between the
scrubber and the repairer is that the repairer will freeze the fs during
setup, which means that the values should match exactly.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
fs/xfs/Makefile | 1 +
fs/xfs/scrub/fscounters.c | 27 +++++++-------
fs/xfs/scrub/fscounters.h | 20 +++++++++++
fs/xfs/scrub/fscounters_repair.c | 72 ++++++++++++++++++++++++++++++++++++++
fs/xfs/scrub/repair.h | 2 +
fs/xfs/scrub/scrub.c | 2 +
fs/xfs/scrub/trace.c | 1 +
fs/xfs/scrub/trace.h | 21 +++++++++--
8 files changed, 128 insertions(+), 18 deletions(-)
create mode 100644 fs/xfs/scrub/fscounters.h
create mode 100644 fs/xfs/scrub/fscounters_repair.c

diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
index 1efc3b7727dc0..a6a455ac5a38b 100644
--- a/fs/xfs/Makefile
+++ b/fs/xfs/Makefile
@@ -192,6 +192,7 @@ xfs-y += $(addprefix scrub/, \
alloc_repair.o \
bmap_repair.o \
cow_repair.o \
+ fscounters_repair.o \
ialloc_repair.o \
inode_repair.o \
newbt.o \
diff --git a/fs/xfs/scrub/fscounters.c b/fs/xfs/scrub/fscounters.c
index 893c5a6e3ddb0..d310737c88236 100644
--- a/fs/xfs/scrub/fscounters.c
+++ b/fs/xfs/scrub/fscounters.c
@@ -22,6 +22,7 @@
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/trace.h"
+#include "scrub/fscounters.h"

/*
* FS Summary Counters
@@ -48,17 +49,6 @@
* our tolerance for mismatch between expected and actual counter values.
*/

-struct xchk_fscounters {
- struct xfs_scrub *sc;
- uint64_t icount;
- uint64_t ifree;
- uint64_t fdblocks;
- uint64_t frextents;
- unsigned long long icount_min;
- unsigned long long icount_max;
- bool frozen;
-};
-
/*
* Since the expected value computation is lockless but only browses incore
* values, the percpu counters should be fairly close to each other. However,
@@ -235,8 +225,13 @@ xchk_setup_fscounters(
* Pause all writer activity in the filesystem while we're scrubbing to
* reduce the likelihood of background perturbations to the counters
* throwing off our calculations.
+ *
+ * If we're repairing, we need to prevent any other thread from
+ * changing the global fs summary counters while we're repairing them.
+ * This requires the fs to be frozen, which will disable background
+ * reclaim and purge all inactive inodes.
*/
- if (sc->flags & XCHK_TRY_HARDER) {
+ if ((sc->flags & XCHK_TRY_HARDER) || xchk_could_repair(sc)) {
error = xchk_fscounters_freeze(sc);
if (error)
return error;
@@ -254,7 +249,9 @@ xchk_setup_fscounters(
* set the INCOMPLETE flag even when a negative errno is returned. This care
* must be taken with certain errno values (i.e. EFSBADCRC, EFSCORRUPTED,
* ECANCELED) that are absorbed into a scrub state flag update by
- * xchk_*_process_error.
+ * xchk_*_process_error. Scrub and repair share the same incore data
+ * structures, so the INCOMPLETE flag is critical to prevent a repair based on
+ * insufficient information.
*/

/* Count free space btree blocks manually for pre-lazysbcount filesystems. */
@@ -482,6 +479,10 @@ xchk_fscount_within_range(
if (curr_value == expected)
return true;

+ /* We require exact matches when repair is running. */
+ if (sc->sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR)
+ return false;
+
min_value = min(old_value, curr_value);
max_value = max(old_value, curr_value);

diff --git a/fs/xfs/scrub/fscounters.h b/fs/xfs/scrub/fscounters.h
new file mode 100644
index 0000000000000..461a13d25f4b3
--- /dev/null
+++ b/fs/xfs/scrub/fscounters.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2021-2024 Oracle. All Rights Reserved.
+ * Author: Darrick J. Wong <djwong@kernel.org>
+ */
+#ifndef __XFS_SCRUB_FSCOUNTERS_H__
+#define __XFS_SCRUB_FSCOUNTERS_H__
+
+struct xchk_fscounters {
+ struct xfs_scrub *sc;
+ uint64_t icount;
+ uint64_t ifree;
+ uint64_t fdblocks;
+ uint64_t frextents;
+ unsigned long long icount_min;
+ unsigned long long icount_max;
+ bool frozen;
+};
+
+#endif /* __XFS_SCRUB_FSCOUNTERS_H__ */
diff --git a/fs/xfs/scrub/fscounters_repair.c b/fs/xfs/scrub/fscounters_repair.c
new file mode 100644
index 0000000000000..94cdb852bee46
--- /dev/null
+++ b/fs/xfs/scrub/fscounters_repair.c
@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2018-2024 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_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 "xfs_ialloc.h"
+#include "xfs_rmap.h"
+#include "xfs_health.h"
+#include "scrub/xfs_scrub.h"
+#include "scrub/scrub.h"
+#include "scrub/common.h"
+#include "scrub/trace.h"
+#include "scrub/repair.h"
+#include "scrub/fscounters.h"
+
+/*
+ * FS Summary Counters
+ * ===================
+ *
+ * We correct errors in the filesystem summary counters by setting them to the
+ * values computed during the obligatory scrub phase. However, we must be
+ * careful not to allow any other thread to change the counters while we're
+ * computing and setting new values. To achieve this, we freeze the
+ * filesystem for the whole operation if the REPAIR flag is set. The checking
+ * function is stricter when we've frozen the fs.
+ */
+
+/*
+ * Reset the superblock counters. Caller is responsible for freezing the
+ * filesystem during the calculation and reset phases.
+ */
+int
+xrep_fscounters(
+ struct xfs_scrub *sc)
+{
+ struct xfs_mount *mp = sc->mp;
+ struct xchk_fscounters *fsc = sc->buf;
+
+ /*
+ * Reinitialize the in-core counters from what we computed. We froze
+ * the filesystem, so there shouldn't be anyone else trying to modify
+ * these counters.
+ */
+ if (!fsc->frozen) {
+ ASSERT(fsc->frozen);
+ return -EFSCORRUPTED;
+ }
+
+ trace_xrep_reset_counters(mp, fsc);
+
+ percpu_counter_set(&mp->m_icount, fsc->icount);
+ percpu_counter_set(&mp->m_ifree, fsc->ifree);
+ percpu_counter_set(&mp->m_fdblocks, fsc->fdblocks);
+ percpu_counter_set(&mp->m_frextents, fsc->frextents);
+ mp->m_sb.sb_frextents = fsc->frextents;
+
+ return 0;
+}
diff --git a/fs/xfs/scrub/repair.h b/fs/xfs/scrub/repair.h
index 8edac0150e960..2ff2bb79c540c 100644
--- a/fs/xfs/scrub/repair.h
+++ b/fs/xfs/scrub/repair.h
@@ -117,6 +117,7 @@ int xrep_bmap_data(struct xfs_scrub *sc);
int xrep_bmap_attr(struct xfs_scrub *sc);
int xrep_bmap_cow(struct xfs_scrub *sc);
int xrep_nlinks(struct xfs_scrub *sc);
+int xrep_fscounters(struct xfs_scrub *sc);

#ifdef CONFIG_XFS_RT
int xrep_rtbitmap(struct xfs_scrub *sc);
@@ -198,6 +199,7 @@ xrep_setup_nothing(
#define xrep_quota xrep_notsupported
#define xrep_quotacheck xrep_notsupported
#define xrep_nlinks xrep_notsupported
+#define xrep_fscounters xrep_notsupported

#endif /* CONFIG_XFS_ONLINE_REPAIR */

diff --git a/fs/xfs/scrub/scrub.c b/fs/xfs/scrub/scrub.c
index 0f23b7f36d4a5..aeac9cae4ad4c 100644
--- a/fs/xfs/scrub/scrub.c
+++ b/fs/xfs/scrub/scrub.c
@@ -364,7 +364,7 @@ static const struct xchk_meta_ops meta_scrub_ops[] = {
.type = ST_FS,
.setup = xchk_setup_fscounters,
.scrub = xchk_fscounters,
- .repair = xrep_notsupported,
+ .repair = xrep_fscounters,
},
[XFS_SCRUB_TYPE_QUOTACHECK] = { /* quota counters */
.type = ST_FS,
diff --git a/fs/xfs/scrub/trace.c b/fs/xfs/scrub/trace.c
index 2d5a330afe10c..b8f3795f7d9b4 100644
--- a/fs/xfs/scrub/trace.c
+++ b/fs/xfs/scrub/trace.c
@@ -24,6 +24,7 @@
#include "scrub/quota.h"
#include "scrub/iscan.h"
#include "scrub/nlinks.h"
+#include "scrub/fscounters.h"

/* Figure out which block the btree cursor was pointing to. */
static inline xfs_fsblock_t
diff --git a/fs/xfs/scrub/trace.h b/fs/xfs/scrub/trace.h
index 86af0efa15d7c..88e921f4efd26 100644
--- a/fs/xfs/scrub/trace.h
+++ b/fs/xfs/scrub/trace.h
@@ -24,6 +24,7 @@ struct xfarray_sortinfo;
struct xchk_dqiter;
struct xchk_iscan;
struct xchk_nlink;
+struct xchk_fscounters;

/*
* ftrace's __print_symbolic requires that all enum values be wrapped in the
@@ -1777,16 +1778,28 @@ TRACE_EVENT(xrep_calc_ag_resblks_btsize,
__entry->refcbt_sz)
)
TRACE_EVENT(xrep_reset_counters,
- TP_PROTO(struct xfs_mount *mp),
- TP_ARGS(mp),
+ TP_PROTO(struct xfs_mount *mp, struct xchk_fscounters *fsc),
+ TP_ARGS(mp, fsc),
TP_STRUCT__entry(
__field(dev_t, dev)
+ __field(uint64_t, icount)
+ __field(uint64_t, ifree)
+ __field(uint64_t, fdblocks)
+ __field(uint64_t, frextents)
),
TP_fast_assign(
__entry->dev = mp->m_super->s_dev;
+ __entry->icount = fsc->icount;
+ __entry->ifree = fsc->ifree;
+ __entry->fdblocks = fsc->fdblocks;
+ __entry->frextents = fsc->frextents;
),
- TP_printk("dev %d:%d",
- MAJOR(__entry->dev), MINOR(__entry->dev))
+ TP_printk("dev %d:%d icount %llu ifree %llu fdblocks %llu frextents %llu",
+ MAJOR(__entry->dev), MINOR(__entry->dev),
+ __entry->icount,
+ __entry->ifree,
+ __entry->fdblocks,
+ __entry->frextents)
)

DECLARE_EVENT_CLASS(xrep_newbt_extent_class,