xfs: create global stats and stats_clear in sysfs

Currently, xfs global stats are in procfs. This patch introduces
(replicates) the global stats in sysfs. Additionally a stats_clear file
is introduced in sysfs.

Signed-off-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

fs/xfs/xfs_sysfs.c

@@ -21,6 +21,7 @@
 #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;
@@ -38,6 +39,8 @@ to_attr(struct attribute *attr)
 	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
 
@@ -125,6 +128,78 @@ struct kobj_type xfs_dbg_ktype = {
 
 #endif /* DEBUG */
 
+
+/* stats */
+
+STATIC ssize_t
+stats_show(
+	char	*buf,
+	void	*data)
+{
+	return xfs_stats_format(buf);
+}
+XFS_SYSFS_ATTR_RO(stats);
+
+STATIC ssize_t
+stats_clear_store(
+	const char	*buf,
+	size_t		count,
+	void		*data)
+{
+	int		ret;
+	int		val;
+
+	ret = kstrtoint(buf, 0, &val);
+	if (ret)
+		return ret;
+
+	if (val != 1)
+		return -EINVAL;
+	xfs_stats_clearall();
+	return count;
+}
+XFS_SYSFS_ATTR_WO(stats_clear);
+
+static struct attribute *xfs_stats_attrs[] = {
+	ATTR_LIST(stats),
+	ATTR_LIST(stats_clear),
+	NULL,
+};
+
+STATIC ssize_t
+xfs_stats_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_stats_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_stats_ops = {
+	.show = xfs_stats_show,
+	.store = xfs_stats_store,
+};
+
+struct kobj_type xfs_stats_ktype = {
+	.release = xfs_sysfs_release,
+	.sysfs_ops = &xfs_stats_ops,
+	.default_attrs = xfs_stats_attrs,
+};
+
 /* xlog */
 
 STATIC ssize_t