[PATCH v3] ubifs: ubifs to export filesystem error counters
Stefan Schaeckeler
schaecsn at gmx.net
Wed Oct 27 23:21:24 PDT 2021
From: Stefan Schaeckeler <sschaeck at cisco.com>
Not all ubifs filesystem errors are propagated to userspace.
Export bad magic, bad node and crc errors via sysfs. This allows userspace
to notice filesystem errors:
/sys/fs/ubifs/ubiX_Y/errors_magic
/sys/fs/ubifs/ubiX_Y/errors_node
/sys/fs/ubifs/ubiX_Y/errors_crc
The counters are reset to 0 with a remount.
Signed-off-by: Stefan Schaeckeler <sschaeck at cisco.com>
---
Changes in v3:
- Added Documentation/ABI/testing/sysfs-fs-ubifs
- Added Documentation/ABI/testing/sysfs-fs-ubifs to MAINTAINERS
Changes in v2:
- Merged sysfs.h header into ubifs.h.
- io.c: wrapped incrementing error counters into new functions
record_*_error().
- sysfs.c: removed sysfs write callback for clearing stats.
- sysfs.c: ubifs_sysfs_register(): free c->stats on error.
- sysfs.c: use sysfs_emit().
Documentation/ABI/testing/sysfs-fs-ubifs | 35 ++++++
MAINTAINERS | 1 +
fs/ubifs/Makefile | 2 +-
fs/ubifs/io.c | 21 ++++
fs/ubifs/super.c | 16 ++-
fs/ubifs/sysfs.c | 153 +++++++++++++++++++++++
fs/ubifs/ubifs.h | 35 ++++++
7 files changed, 261 insertions(+), 2 deletions(-)
create mode 100644 Documentation/ABI/testing/sysfs-fs-ubifs
create mode 100644 fs/ubifs/sysfs.c
diff --git a/Documentation/ABI/testing/sysfs-fs-ubifs b/Documentation/ABI/testing/sysfs-fs-ubifs
new file mode 100644
index 000000000000..19a8ebf7fe61
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-fs-ubifs
@@ -0,0 +1,35 @@
+What: /sys/fs/ubifsX_Y/error_magic
+Date: October 2021
+KernelVersion: 5.16
+Contact: linux-mtd at lists.infradead.org
+Description:
+ Exposes magic errors: every node starts with a magic number.
+
+ This counter keeps track of the number of accesses of nodes
+ with a corrupted magic number.
+
+ The counter is reset to 0 with a remount.
+
+What: /sys/fs/ubifsX_Y/error_node
+Date: October 2021
+KernelVersion: 5.16
+Contact: linux-mtd at lists.infradead.org
+Description:
+ Exposes node errors. Every node embeds its type.
+
+ This counter keeps track of the number of accesses of nodes
+ with a corrupted node type.
+
+ The counter is reset to 0 with a remount.
+
+What: /sys/fs/ubifsX_Y/error_crc
+Date: October 2021
+KernelVersion: 5.16
+Contact: linux-mtd at lists.infradead.org
+Description:
+ Exposes crc errors: every node embeds a crc checksum.
+
+ This counter keeps track of the number of accesses of nodes
+ with a bad crc checksum.
+
+ The counter is reset to 0 with a remount.
diff --git a/MAINTAINERS b/MAINTAINERS
index b43662a9a5f3..a8f0e3e38b2e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -19105,6 +19105,7 @@ S: Supported
W: http://www.linux-mtd.infradead.org/doc/ubifs.html
T: git git://git.kernel.org/pub/scm/linux/kernel/git/rw/ubifs.git next
T: git git://git.kernel.org/pub/scm/linux/kernel/git/rw/ubifs.git fixes
+F: Documentation/ABI/testing/sysfs-fs-ubifs
F: Documentation/filesystems/ubifs-authentication.rst
F: Documentation/filesystems/ubifs.rst
F: fs/ubifs/
diff --git a/fs/ubifs/Makefile b/fs/ubifs/Makefile
index 5c4b845754a7..314c80b24a76 100644
--- a/fs/ubifs/Makefile
+++ b/fs/ubifs/Makefile
@@ -5,7 +5,7 @@ ubifs-y += shrinker.o journal.o file.o dir.o super.o sb.o io.o
ubifs-y += tnc.o master.o scan.o replay.o log.o commit.o gc.o orphan.o
ubifs-y += budget.o find.o tnc_commit.o compress.o lpt.o lprops.o
ubifs-y += recovery.o ioctl.o lpt_commit.o tnc_misc.o debug.o
-ubifs-y += misc.o
+ubifs-y += misc.o sysfs.o
ubifs-$(CONFIG_FS_ENCRYPTION) += crypto.o
ubifs-$(CONFIG_UBIFS_FS_XATTR) += xattr.o
ubifs-$(CONFIG_UBIFS_FS_AUTHENTICATION) += auth.o
diff --git a/fs/ubifs/io.c b/fs/ubifs/io.c
index 00b61dba62b7..789a7813f3fa 100644
--- a/fs/ubifs/io.c
+++ b/fs/ubifs/io.c
@@ -194,6 +194,24 @@ int ubifs_is_mapped(const struct ubifs_info *c, int lnum)
return err;
}
+static void record_magic_error(struct ubifs_stats_info *stats)
+{
+ if (stats)
+ stats->magic_errors++;
+}
+
+static void record_node_error(struct ubifs_stats_info *stats)
+{
+ if (stats)
+ stats->node_errors++;
+}
+
+static void record_crc_error(struct ubifs_stats_info *stats)
+{
+ if (stats)
+ stats->crc_errors++;
+}
+
/**
* ubifs_check_node - check node.
* @c: UBIFS file-system description object
@@ -238,6 +256,7 @@ int ubifs_check_node(const struct ubifs_info *c, const void *buf, int len,
if (!quiet)
ubifs_err(c, "bad magic %#08x, expected %#08x",
magic, UBIFS_NODE_MAGIC);
+ record_magic_error(c->stats);
err = -EUCLEAN;
goto out;
}
@@ -246,6 +265,7 @@ int ubifs_check_node(const struct ubifs_info *c, const void *buf, int len,
if (type < 0 || type >= UBIFS_NODE_TYPES_CNT) {
if (!quiet)
ubifs_err(c, "bad node type %d", type);
+ record_node_error(c->stats);
goto out;
}
@@ -270,6 +290,7 @@ int ubifs_check_node(const struct ubifs_info *c, const void *buf, int len,
if (!quiet)
ubifs_err(c, "bad CRC: calculated %#08x, read %#08x",
crc, node_crc);
+ record_crc_error(c->stats);
err = -EUCLEAN;
goto out;
}
diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index f0fb25727d96..a4e3a143fb1b 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -1264,6 +1264,10 @@ static int mount_ubifs(struct ubifs_info *c)
if (err)
return err;
+ err = ubifs_sysfs_register(c);
+ if (err)
+ goto out_debugging;
+
err = check_volume_empty(c);
if (err)
goto out_free;
@@ -1641,6 +1645,8 @@ static int mount_ubifs(struct ubifs_info *c)
vfree(c->sbuf);
kfree(c->bottom_up_buf);
kfree(c->sup_node);
+ ubifs_sysfs_unregister(c);
+out_debugging:
ubifs_debugging_exit(c);
return err;
}
@@ -1684,6 +1690,7 @@ static void ubifs_umount(struct ubifs_info *c)
kfree(c->bottom_up_buf);
kfree(c->sup_node);
ubifs_debugging_exit(c);
+ ubifs_sysfs_unregister(c);
}
/**
@@ -2436,14 +2443,20 @@ static int __init ubifs_init(void)
dbg_debugfs_init();
+ err = ubifs_sysfs_init();
+ if (err)
+ goto out_dbg;
+
err = register_filesystem(&ubifs_fs_type);
if (err) {
pr_err("UBIFS error (pid %d): cannot register file system, error %d",
current->pid, err);
- goto out_dbg;
+ goto out_sysfs;
}
return 0;
+out_sysfs:
+ ubifs_sysfs_exit();
out_dbg:
dbg_debugfs_exit();
ubifs_compressors_exit();
@@ -2462,6 +2475,7 @@ static void __exit ubifs_exit(void)
WARN_ON(atomic_long_read(&ubifs_clean_zn_cnt) != 0);
dbg_debugfs_exit();
+ ubifs_sysfs_exit();
ubifs_compressors_exit();
unregister_shrinker(&ubifs_shrinker_info);
diff --git a/fs/ubifs/sysfs.c b/fs/ubifs/sysfs.c
new file mode 100644
index 000000000000..0eb3d7d12450
--- /dev/null
+++ b/fs/ubifs/sysfs.c
@@ -0,0 +1,153 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2021 Cisco Systems
+ *
+ * Author: Stefan Schaeckeler
+ */
+
+
+#include <linux/fs.h>
+#include "ubifs.h"
+
+enum attr_id_t {
+ attr_errors_magic,
+ attr_errors_node,
+ attr_errors_crc,
+};
+
+struct ubifs_attr {
+ struct attribute attr;
+ enum attr_id_t attr_id;
+};
+
+#define UBIFS_ATTR(_name, _mode, _id) \
+static struct ubifs_attr ubifs_attr_##_name = { \
+ .attr = {.name = __stringify(_name), .mode = _mode }, \
+ .attr_id = attr_##_id, \
+}
+
+#define UBIFS_ATTR_FUNC(_name, _mode) UBIFS_ATTR(_name, _mode, _name)
+
+UBIFS_ATTR_FUNC(errors_magic, 0444);
+UBIFS_ATTR_FUNC(errors_crc, 0444);
+UBIFS_ATTR_FUNC(errors_node, 0444);
+
+#define ATTR_LIST(name) (&ubifs_attr_##name.attr)
+
+static struct attribute *ubifs_attrs[] = {
+ ATTR_LIST(errors_magic),
+ ATTR_LIST(errors_node),
+ ATTR_LIST(errors_crc),
+ NULL,
+};
+
+static ssize_t ubifs_attr_show(struct kobject *kobj,
+ struct attribute *attr, char *buf)
+{
+ struct ubifs_info *sbi = container_of(kobj, struct ubifs_info,
+ kobj);
+
+ struct ubifs_attr *a = container_of(attr, struct ubifs_attr, attr);
+
+ switch (a->attr_id) {
+ case attr_errors_magic:
+ return sysfs_emit(buf, "%u\n", sbi->stats->magic_errors);
+ case attr_errors_node:
+ return sysfs_emit(buf, "%u\n", sbi->stats->node_errors);
+ case attr_errors_crc:
+ return sysfs_emit(buf, "%u\n", sbi->stats->crc_errors);
+ }
+ return 0;
+};
+
+static void ubifs_sb_release(struct kobject *kobj)
+{
+ struct ubifs_info *c = container_of(kobj, struct ubifs_info, kobj);
+
+ complete(&c->kobj_unregister);
+}
+
+static const struct sysfs_ops ubifs_attr_ops = {
+ .show = ubifs_attr_show,
+};
+
+static struct kobj_type ubifs_sb_ktype = {
+ .default_attrs = ubifs_attrs,
+ .sysfs_ops = &ubifs_attr_ops,
+ .release = ubifs_sb_release,
+};
+
+static struct kobj_type ubifs_ktype = {
+ .sysfs_ops = &ubifs_attr_ops,
+};
+
+static struct kset ubifs_kset = {
+ .kobj = {.ktype = &ubifs_ktype},
+};
+
+int ubifs_sysfs_register(struct ubifs_info *c)
+{
+ int ret, n;
+ char dfs_dir_name[UBIFS_DFS_DIR_LEN+1];
+
+ c->stats = kzalloc(sizeof(struct ubifs_stats_info), GFP_KERNEL);
+ if (!c->stats) {
+ ret = -ENOMEM;
+ goto out_last;
+ }
+ n = snprintf(dfs_dir_name, UBIFS_DFS_DIR_LEN + 1, UBIFS_DFS_DIR_NAME,
+ c->vi.ubi_num, c->vi.vol_id);
+
+ if (n == UBIFS_DFS_DIR_LEN) {
+ /* The array size is too small */
+ ret = -EINVAL;
+ goto out_free;
+ }
+
+ c->kobj.kset = &ubifs_kset;
+ init_completion(&c->kobj_unregister);
+
+ ret = kobject_init_and_add(&c->kobj, &ubifs_sb_ktype, NULL,
+ "%s", dfs_dir_name);
+ if (ret)
+ goto out_put;
+
+ return 0;
+
+out_put:
+ kobject_put(&c->kobj);
+ wait_for_completion(&c->kobj_unregister);
+out_free:
+ kfree(c->stats);
+out_last:
+ ubifs_err(c, "cannot create sysfs entry for ubifs%d_%d, error %d\n",
+ c->vi.ubi_num, c->vi.vol_id, ret);
+ return ret;
+}
+
+void ubifs_sysfs_unregister(struct ubifs_info *c)
+{
+ kobject_del(&c->kobj);
+ kobject_put(&c->kobj);
+ wait_for_completion(&c->kobj_unregister);
+
+ kfree(c->stats);
+}
+
+int __init ubifs_sysfs_init(void)
+{
+ int ret;
+
+ kobject_set_name(&ubifs_kset.kobj, "ubifs");
+ ubifs_kset.kobj.parent = fs_kobj;
+ ret = kset_register(&ubifs_kset);
+
+ return ret;
+}
+
+void ubifs_sysfs_exit(void)
+{
+ kset_unregister(&ubifs_kset);
+}
diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index c38066ce9ab0..f55828c0a300 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -27,6 +27,8 @@
#include <linux/security.h>
#include <linux/xattr.h>
#include <linux/random.h>
+#include <linux/sysfs.h>
+#include <linux/completion.h>
#include <crypto/hash_info.h>
#include <crypto/hash.h>
#include <crypto/algapi.h>
@@ -155,6 +157,13 @@
#define UBIFS_HMAC_ARR_SZ 0
#endif
+/*
+ * The UBIFS sysfs directory name pattern and maximum name length (3 for "ubi"
+ * + 1 for "_" and plus 2x2 for 2 UBI numbers and 1 for the trailing zero byte.
+ */
+#define UBIFS_DFS_DIR_NAME "ubi%d_%d"
+#define UBIFS_DFS_DIR_LEN (3 + 1 + 2*2 + 1)
+
/*
* Lockdep classes for UBIFS inode @ui_mutex.
*/
@@ -990,6 +999,18 @@ struct ubifs_budg_info {
int dent_budget;
};
+/**
+ * ubifs_stats_info - per-FS statistics information.
+ * @magic_errors: number of bad magic numbers (will be reset with a new mount).
+ * @node_errors: number of bad nodes (will be reset with a new mount).
+ * @crc_errors: number of bad crcs (will be reset with a new mount).
+ */
+struct ubifs_stats_info {
+ unsigned int magic_errors;
+ unsigned int node_errors;
+ unsigned int crc_errors;
+};
+
struct ubifs_debug_info;
/**
@@ -1251,6 +1272,10 @@ struct ubifs_debug_info;
* @mount_opts: UBIFS-specific mount options
*
* @dbg: debugging-related information
+ * @stats: statistics exported over sysfs
+ *
+ * @kobj: kobject for /sys/fs/ubifs/
+ * @kobj_unregister: completion to unregister sysfs kobject
*/
struct ubifs_info {
struct super_block *vfs_sb;
@@ -1286,6 +1311,9 @@ struct ubifs_info {
spinlock_t cs_lock;
wait_queue_head_t cmt_wq;
+ struct kobject kobj;
+ struct completion kobj_unregister;
+
unsigned int big_lpt:1;
unsigned int space_fixup:1;
unsigned int double_hash:1;
@@ -1493,6 +1521,7 @@ struct ubifs_info {
struct ubifs_mount_opts mount_opts;
struct ubifs_debug_info *dbg;
+ struct ubifs_stats_info *stats;
};
extern struct list_head ubifs_infos;
@@ -2072,6 +2101,12 @@ void ubifs_compress(const struct ubifs_info *c, const void *in_buf, int in_len,
int ubifs_decompress(const struct ubifs_info *c, const void *buf, int len,
void *out, int *out_len, int compr_type);
+/* sysfs.c */
+int ubifs_sysfs_init(void);
+void ubifs_sysfs_exit(void);
+int ubifs_sysfs_register(struct ubifs_info *c);
+void ubifs_sysfs_unregister(struct ubifs_info *c);
+
#include "debug.h"
#include "misc.h"
#include "key.h"
--
2.33.0
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