linux/fs/xfs/xfs_sysfs.c
Brian Foster 609adfc2ed xfs: debug mode log record crc error injection
XFS now uses CRC verification over a limited section of the log to
detect torn writes prior to a crash. This is difficult to test directly
due to the timing and hardware requirements to cause a short write.

Add a mechanism to inject CRC errors into log records to facilitate
testing torn write detection during log recovery. This mechanism is
dangerous and can result in filesystem corruption. Thus, it is only
available in DEBUG mode for testing/development purposes. Set a non-zero
value to the following sysfs entry to enable error injection:

	/sys/fs/xfs/<dev>/log/log_badcrc_factor

Once enabled, XFS intentionally writes an invalid CRC to a log record at
some random point in the future based on the provided frequency. The
filesystem immediately shuts down once the record has been written to
the physical log to prevent metadata writeback (e.g., AIL insertion)
once the log write completes. This helps reasonably simulate a torn
write to the log as the affected record must be safe to discard. The
next mount after the intentional shutdown requires log recovery and
should detect and recover from the torn write.

Note again that this _will_ result in data loss or worse. For testing
and development purposes only!

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-01-05 07:41:16 +11:00

307 lines
6.3 KiB
C

/*
* Copyright (c) 2014 Red Hat, Inc.
* All Rights Reserved.
*
* 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.
*
* 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_sysfs.h"
#include "xfs_log_format.h"
#include "xfs_log.h"
#include "xfs_log_priv.h"
#include "xfs_stats.h"
struct xfs_sysfs_attr {
struct attribute attr;
ssize_t (*show)(struct kobject *kobject, char *buf);
ssize_t (*store)(struct kobject *kobject, const char *buf,
size_t count);
};
static inline struct xfs_sysfs_attr *
to_attr(struct attribute *attr)
{
return container_of(attr, struct xfs_sysfs_attr, attr);
}
#define XFS_SYSFS_ATTR_RW(name) \
static struct xfs_sysfs_attr xfs_sysfs_attr_##name = __ATTR_RW(name)
#define XFS_SYSFS_ATTR_RO(name) \
static struct xfs_sysfs_attr xfs_sysfs_attr_##name = __ATTR_RO(name)
#define XFS_SYSFS_ATTR_WO(name) \
static struct xfs_sysfs_attr xfs_sysfs_attr_##name = __ATTR_WO(name)
#define ATTR_LIST(name) &xfs_sysfs_attr_##name.attr
/*
* xfs_mount kobject. This currently has no attributes and thus no need for show
* and store helpers. The mp kobject serves as the per-mount parent object that
* is identified by the fsname under sysfs.
*/
struct kobj_type xfs_mp_ktype = {
.release = xfs_sysfs_release,
};
STATIC ssize_t
xfs_sysfs_object_show(
struct kobject *kobject,
struct attribute *attr,
char *buf)
{
struct xfs_sysfs_attr *xfs_attr = to_attr(attr);
return xfs_attr->show ? xfs_attr->show(kobject, buf) : 0;
}
STATIC ssize_t
xfs_sysfs_object_store(
struct kobject *kobject,
struct attribute *attr,
const char *buf,
size_t count)
{
struct xfs_sysfs_attr *xfs_attr = to_attr(attr);
return xfs_attr->store ? xfs_attr->store(kobject, buf, count) : 0;
}
static const struct sysfs_ops xfs_sysfs_ops = {
.show = xfs_sysfs_object_show,
.store = xfs_sysfs_object_store,
};
#ifdef DEBUG
/* debug */
STATIC ssize_t
log_recovery_delay_store(
struct kobject *kobject,
const char *buf,
size_t count)
{
int ret;
int val;
ret = kstrtoint(buf, 0, &val);
if (ret)
return ret;
if (val < 0 || val > 60)
return -EINVAL;
xfs_globals.log_recovery_delay = val;
return count;
}
STATIC ssize_t
log_recovery_delay_show(
struct kobject *kobject,
char *buf)
{
return snprintf(buf, PAGE_SIZE, "%d\n", xfs_globals.log_recovery_delay);
}
XFS_SYSFS_ATTR_RW(log_recovery_delay);
static struct attribute *xfs_dbg_attrs[] = {
ATTR_LIST(log_recovery_delay),
NULL,
};
struct kobj_type xfs_dbg_ktype = {
.release = xfs_sysfs_release,
.sysfs_ops = &xfs_sysfs_ops,
.default_attrs = xfs_dbg_attrs,
};
#endif /* DEBUG */
/* stats */
static inline struct xstats *
to_xstats(struct kobject *kobject)
{
struct xfs_kobj *kobj = to_kobj(kobject);
return container_of(kobj, struct xstats, xs_kobj);
}
STATIC ssize_t
stats_show(
struct kobject *kobject,
char *buf)
{
struct xstats *stats = to_xstats(kobject);
return xfs_stats_format(stats->xs_stats, buf);
}
XFS_SYSFS_ATTR_RO(stats);
STATIC ssize_t
stats_clear_store(
struct kobject *kobject,
const char *buf,
size_t count)
{
int ret;
int val;
struct xstats *stats = to_xstats(kobject);
ret = kstrtoint(buf, 0, &val);
if (ret)
return ret;
if (val != 1)
return -EINVAL;
xfs_stats_clearall(stats->xs_stats);
return count;
}
XFS_SYSFS_ATTR_WO(stats_clear);
static struct attribute *xfs_stats_attrs[] = {
ATTR_LIST(stats),
ATTR_LIST(stats_clear),
NULL,
};
struct kobj_type xfs_stats_ktype = {
.release = xfs_sysfs_release,
.sysfs_ops = &xfs_sysfs_ops,
.default_attrs = xfs_stats_attrs,
};
/* xlog */
static inline struct xlog *
to_xlog(struct kobject *kobject)
{
struct xfs_kobj *kobj = to_kobj(kobject);
return container_of(kobj, struct xlog, l_kobj);
}
STATIC ssize_t
log_head_lsn_show(
struct kobject *kobject,
char *buf)
{
int cycle;
int block;
struct xlog *log = to_xlog(kobject);
spin_lock(&log->l_icloglock);
cycle = log->l_curr_cycle;
block = log->l_curr_block;
spin_unlock(&log->l_icloglock);
return snprintf(buf, PAGE_SIZE, "%d:%d\n", cycle, block);
}
XFS_SYSFS_ATTR_RO(log_head_lsn);
STATIC ssize_t
log_tail_lsn_show(
struct kobject *kobject,
char *buf)
{
int cycle;
int block;
struct xlog *log = to_xlog(kobject);
xlog_crack_atomic_lsn(&log->l_tail_lsn, &cycle, &block);
return snprintf(buf, PAGE_SIZE, "%d:%d\n", cycle, block);
}
XFS_SYSFS_ATTR_RO(log_tail_lsn);
STATIC ssize_t
reserve_grant_head_show(
struct kobject *kobject,
char *buf)
{
int cycle;
int bytes;
struct xlog *log = to_xlog(kobject);
xlog_crack_grant_head(&log->l_reserve_head.grant, &cycle, &bytes);
return snprintf(buf, PAGE_SIZE, "%d:%d\n", cycle, bytes);
}
XFS_SYSFS_ATTR_RO(reserve_grant_head);
STATIC ssize_t
write_grant_head_show(
struct kobject *kobject,
char *buf)
{
int cycle;
int bytes;
struct xlog *log = to_xlog(kobject);
xlog_crack_grant_head(&log->l_write_head.grant, &cycle, &bytes);
return snprintf(buf, PAGE_SIZE, "%d:%d\n", cycle, bytes);
}
XFS_SYSFS_ATTR_RO(write_grant_head);
#ifdef DEBUG
STATIC ssize_t
log_badcrc_factor_store(
struct kobject *kobject,
const char *buf,
size_t count)
{
struct xlog *log = to_xlog(kobject);
int ret;
uint32_t val;
ret = kstrtouint(buf, 0, &val);
if (ret)
return ret;
log->l_badcrc_factor = val;
return count;
}
STATIC ssize_t
log_badcrc_factor_show(
struct kobject *kobject,
char *buf)
{
struct xlog *log = to_xlog(kobject);
return snprintf(buf, PAGE_SIZE, "%d\n", log->l_badcrc_factor);
}
XFS_SYSFS_ATTR_RW(log_badcrc_factor);
#endif /* DEBUG */
static struct attribute *xfs_log_attrs[] = {
ATTR_LIST(log_head_lsn),
ATTR_LIST(log_tail_lsn),
ATTR_LIST(reserve_grant_head),
ATTR_LIST(write_grant_head),
#ifdef DEBUG
ATTR_LIST(log_badcrc_factor),
#endif
NULL,
};
struct kobj_type xfs_log_ktype = {
.release = xfs_sysfs_release,
.sysfs_ops = &xfs_sysfs_ops,
.default_attrs = xfs_log_attrs,
};