linux/fs/xfs/xfs_sysfs.c
Brian Foster 80d6d69821 xfs: add log attributes for log lsn and grant head data
Create log attributes to export the current runtime state of the log to
sysfs. Note that the filesystem should be frozen for consistency across
attributes.

The following per-mount attributes are created: log_head_lsn,
log_tail_lsn, reserve_grant_head and write_grant_head. These represent
the physical log head, tail and reserve and write grant heads
respectively. Attribute values are exported in the following format:

	"cycle:[block,byte]"

... where cycle represents the log cycle and [block,bytes] represents
either the basic block or byte offset of the log, depending on the
attribute.  Log sequence number (LSN) values are encoded in basic blocks
and grant heads are encoded in bytes. All values are in decimal format.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-07-15 08:07:48 +10:00

166 lines
3.8 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,
};
/* 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,
};