linux/fs/xfs/xfs_sysfs.c
Brian Foster 2e22717874 xfs: export log_recovery_delay to delay mount time log recovery
XFS log recovery has been discovered to have race conditions with
buffers when I/O errors occur. External tools are available to simulate
I/O errors to XFS, but this alone is not sufficient for testing log
recovery. XFS unconditionally resets the inactive region of the log
prior to log recovery to avoid confusion over processing any partially
written log records that might have been written before an unclean
shutdown. Therefore, unconditional write I/O failures at mount time are
caught by the reset sequence rather than log recovery and hinder the
ability to test the latter.

The device-mapper dm-flakey module uses an up/down timer to define a
cycle for when to fail I/Os. Create a pre log recovery delay tunable
that can be used to coordinate XFS log recovery with I/O errors
simulated by dm-flakey. This facilitates coordination in userspace that
allows the reset of stale log blocks to succeed and writes due to log
recovery to fail. For example, define a dm-flakey instance with an
uptime long enough to allow log reset to succeed and a log recovery
delay long enough to allow the dm-flakey uptime to expire.

The 'log_recovery_delay' sysfs tunable is exported under
/sys/fs/xfs/debug and is only enabled for kernels compiled in XFS debug
mode. The value is exported in units of seconds and allows for a delay
of up to 60 seconds. Note that this is for XFS debug and test
instrumentation purposes only and should not be used by applications. No
delay is enabled by default.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-09-09 11:56:13 +10:00

240 lines
5.0 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"
struct xfs_sysfs_attr {
struct attribute attr;
ssize_t (*show)(char *buf, void *data);
ssize_t (*store)(const char *buf, size_t count, void *data);
};
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 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,
};
#ifdef DEBUG
/* debug */
STATIC ssize_t
log_recovery_delay_store(
const char *buf,
size_t count,
void *data)
{
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(
char *buf,
void *data)
{
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,
};
STATIC ssize_t
xfs_dbg_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(buf, NULL) : 0;
}
STATIC ssize_t
xfs_dbg_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(buf, count, NULL) : 0;
}
static struct sysfs_ops xfs_dbg_ops = {
.show = xfs_dbg_show,
.store = xfs_dbg_store,
};
struct kobj_type xfs_dbg_ktype = {
.release = xfs_sysfs_release,
.sysfs_ops = &xfs_dbg_ops,
.default_attrs = xfs_dbg_attrs,
};
#endif /* DEBUG */
/* xlog */
STATIC ssize_t
log_head_lsn_show(
char *buf,
void *data)
{
struct xlog *log = data;
int cycle;
int block;
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(
char *buf,
void *data)
{
struct xlog *log = data;
int cycle;
int block;
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(
char *buf,
void *data)
{
struct xlog *log = data;
int cycle;
int bytes;
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(
char *buf,
void *data)
{
struct xlog *log = data;
int cycle;
int bytes;
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);
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),
NULL,
};
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
xfs_log_show(
struct kobject *kobject,
struct attribute *attr,
char *buf)
{
struct xlog *log = to_xlog(kobject);
struct xfs_sysfs_attr *xfs_attr = to_attr(attr);
return xfs_attr->show ? xfs_attr->show(buf, log) : 0;
}
STATIC ssize_t
xfs_log_store(
struct kobject *kobject,
struct attribute *attr,
const char *buf,
size_t count)
{
struct xlog *log = to_xlog(kobject);
struct xfs_sysfs_attr *xfs_attr = to_attr(attr);
return xfs_attr->store ? xfs_attr->store(buf, count, log) : 0;
}
static struct sysfs_ops xfs_log_ops = {
.show = xfs_log_show,
.store = xfs_log_store,
};
struct kobj_type xfs_log_ktype = {
.release = xfs_sysfs_release,
.sysfs_ops = &xfs_log_ops,
.default_attrs = xfs_log_attrs,
};