/*
 * 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_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_sysfs.h"
#include "xfs_log.h"
#include "xfs_log_priv.h"
#include "xfs_stats.h"
#include "xfs_mount.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

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,
};

/*
 * xfs_mount kobject. The mp kobject also serves as the per-mount parent object
 * that is identified by the fsname under sysfs.
 */

static inline struct xfs_mount *
to_mp(struct kobject *kobject)
{
        struct xfs_kobj *kobj = to_kobj(kobject);

        return container_of(kobj, struct xfs_mount, m_kobj);
}

#ifdef DEBUG

STATIC ssize_t
fail_writes_store(
        struct kobject          *kobject,
        const char              *buf,
        size_t                  count)
{
        struct xfs_mount        *mp = to_mp(kobject);
        int                     ret;
        int                     val;

        ret = kstrtoint(buf, 0, &val);
        if (ret)
                return ret;

        if (val == 1)
                mp->m_fail_writes = true;
        else if (val == 0)
                mp->m_fail_writes = false;
        else
                return -EINVAL;

        return count;
}

STATIC ssize_t
fail_writes_show(
        struct kobject          *kobject,
        char                    *buf)
{
        struct xfs_mount        *mp = to_mp(kobject);

        return snprintf(buf, PAGE_SIZE, "%d\n", mp->m_fail_writes ? 1 : 0);
}
XFS_SYSFS_ATTR_RW(fail_writes);

#endif /* DEBUG */

static struct attribute *xfs_mp_attrs[] = {
#ifdef DEBUG
        ATTR_LIST(fail_writes),
#endif
        NULL,
};

struct kobj_type xfs_mp_ktype = {
        .release = xfs_sysfs_release,
        .sysfs_ops = &xfs_sysfs_ops,
        .default_attrs = xfs_mp_attrs,
};

#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,
};

/*
 * Metadata IO error configuration
 *
 * The sysfs structure here is:
 *      ...xfs/<dev>/error/<class>/<errno>/<error_attrs>
 *
 * where <class> allows us to discriminate between data IO and metadata IO,
 * and any other future type of IO (e.g. special inode or directory error
 * handling) we care to support.
 */
static inline struct xfs_error_cfg *
to_error_cfg(struct kobject *kobject)
{
        struct xfs_kobj *kobj = to_kobj(kobject);
        return container_of(kobj, struct xfs_error_cfg, kobj);
}

static inline struct xfs_mount *
err_to_mp(struct kobject *kobject)
{
        struct xfs_kobj *kobj = to_kobj(kobject);
        return container_of(kobj, struct xfs_mount, m_error_kobj);
}

static ssize_t
max_retries_show(
        struct kobject  *kobject,
        char            *buf)
{
        struct xfs_error_cfg *cfg = to_error_cfg(kobject);

        return snprintf(buf, PAGE_SIZE, "%d\n", cfg->max_retries);
}

static ssize_t
max_retries_store(
        struct kobject  *kobject,
        const char      *buf,
        size_t          count)
{
        struct xfs_error_cfg *cfg = to_error_cfg(kobject);
        int             ret;
        int             val;

        ret = kstrtoint(buf, 0, &val);
        if (ret)
                return ret;

        if (val < -1)
                return -EINVAL;

        cfg->max_retries = val;
        return count;
}
XFS_SYSFS_ATTR_RW(max_retries);

static ssize_t
retry_timeout_seconds_show(
        struct kobject  *kobject,
        char            *buf)
{
        struct xfs_error_cfg *cfg = to_error_cfg(kobject);

        return snprintf(buf, PAGE_SIZE, "%ld\n",
                        jiffies_to_msecs(cfg->retry_timeout) / MSEC_PER_SEC);
}

static ssize_t
retry_timeout_seconds_store(
        struct kobject  *kobject,
        const char      *buf,
        size_t          count)
{
        struct xfs_error_cfg *cfg = to_error_cfg(kobject);
        int             ret;
        int             val;

        ret = kstrtoint(buf, 0, &val);
        if (ret)
                return ret;

        /* 1 day timeout maximum */
        if (val < 0 || val > 86400)
                return -EINVAL;

        cfg->retry_timeout = msecs_to_jiffies(val * MSEC_PER_SEC);
        return count;
}
XFS_SYSFS_ATTR_RW(retry_timeout_seconds);

static ssize_t
fail_at_unmount_show(
        struct kobject  *kobject,
        char            *buf)
{
        struct xfs_mount        *mp = err_to_mp(kobject);

        return snprintf(buf, PAGE_SIZE, "%d\n", mp->m_fail_unmount);
}

static ssize_t
fail_at_unmount_store(
        struct kobject  *kobject,
        const char      *buf,
        size_t          count)
{
        struct xfs_mount        *mp = err_to_mp(kobject);
        int             ret;
        int             val;

        ret = kstrtoint(buf, 0, &val);
        if (ret)
                return ret;

        if (val < 0 || val > 1)
                return -EINVAL;

        mp->m_fail_unmount = val;
        return count;
}
XFS_SYSFS_ATTR_RW(fail_at_unmount);

static struct attribute *xfs_error_attrs[] = {
        ATTR_LIST(max_retries),
        ATTR_LIST(retry_timeout_seconds),
        NULL,
};


struct kobj_type xfs_error_cfg_ktype = {
        .release = xfs_sysfs_release,
        .sysfs_ops = &xfs_sysfs_ops,
        .default_attrs = xfs_error_attrs,
};

struct kobj_type xfs_error_ktype = {
        .release = xfs_sysfs_release,
        .sysfs_ops = &xfs_sysfs_ops,
};

/*
 * Error initialization tables. These need to be ordered in the same
 * order as the enums used to index the array. All class init tables need to
 * define a "default" behaviour as the first entry, all other entries can be
 * empty.
 */
struct xfs_error_init {
        char            *name;
        int             max_retries;
        int             retry_timeout;  /* in seconds */
};

static const struct xfs_error_init xfs_error_meta_init[XFS_ERR_ERRNO_MAX] = {
        { .name = "default",
          .max_retries = XFS_ERR_RETRY_FOREVER,
          .retry_timeout = 0,
        },
        { .name = "EIO",
          .max_retries = XFS_ERR_RETRY_FOREVER,
          .retry_timeout = 0,
        },
        { .name = "ENOSPC",
          .max_retries = XFS_ERR_RETRY_FOREVER,
          .retry_timeout = 0,
        },
        { .name = "ENODEV",
          .max_retries = 0,
        },
};

static int
xfs_error_sysfs_init_class(
        struct xfs_mount        *mp,
        int                     class,
        const char              *parent_name,
        struct xfs_kobj         *parent_kobj,
        const struct xfs_error_init init[])
{
        struct xfs_error_cfg    *cfg;
        int                     error;
        int                     i;

        ASSERT(class < XFS_ERR_CLASS_MAX);

        error = xfs_sysfs_init(parent_kobj, &xfs_error_ktype,
                                &mp->m_error_kobj, parent_name);
        if (error)
                return error;

        for (i = 0; i < XFS_ERR_ERRNO_MAX; i++) {
                cfg = &mp->m_error_cfg[class][i];
                error = xfs_sysfs_init(&cfg->kobj, &xfs_error_cfg_ktype,
                                        parent_kobj, init[i].name);
                if (error)
                        goto out_error;

                cfg->max_retries = init[i].max_retries;
                cfg->retry_timeout = msecs_to_jiffies(
                                        init[i].retry_timeout * MSEC_PER_SEC);
        }
        return 0;

out_error:
        /* unwind the entries that succeeded */
        for (i--; i >= 0; i--) {
                cfg = &mp->m_error_cfg[class][i];
                xfs_sysfs_del(&cfg->kobj);
        }
        xfs_sysfs_del(parent_kobj);
        return error;
}

int
xfs_error_sysfs_init(
        struct xfs_mount        *mp)
{
        int                     error;

        /* .../xfs/<dev>/error/ */
        error = xfs_sysfs_init(&mp->m_error_kobj, &xfs_error_ktype,
                                &mp->m_kobj, "error");
        if (error)
                return error;

        error = sysfs_create_file(&mp->m_error_kobj.kobject,
                                  ATTR_LIST(fail_at_unmount));

        if (error)
                goto out_error;

        /* .../xfs/<dev>/error/metadata/ */
        error = xfs_error_sysfs_init_class(mp, XFS_ERR_METADATA,
                                "metadata", &mp->m_error_meta_kobj,
                                xfs_error_meta_init);
        if (error)
                goto out_error;

        return 0;

out_error:
        xfs_sysfs_del(&mp->m_error_kobj);
        return error;
}

void
xfs_error_sysfs_del(
        struct xfs_mount        *mp)
{
        struct xfs_error_cfg    *cfg;
        int                     i, j;

        for (i = 0; i < XFS_ERR_CLASS_MAX; i++) {
                for (j = 0; j < XFS_ERR_ERRNO_MAX; j++) {
                        cfg = &mp->m_error_cfg[i][j];

                        xfs_sysfs_del(&cfg->kobj);
                }
        }
        xfs_sysfs_del(&mp->m_error_meta_kobj);
        xfs_sysfs_del(&mp->m_error_kobj);
}

struct xfs_error_cfg *
xfs_error_get_cfg(
        struct xfs_mount        *mp,
        int                     error_class,
        int                     error)
{
        struct xfs_error_cfg    *cfg;

        switch (error) {
        case EIO:
                cfg = &mp->m_error_cfg[error_class][XFS_ERR_EIO];
                break;
        case ENOSPC:
                cfg = &mp->m_error_cfg[error_class][XFS_ERR_ENOSPC];
                break;
        case ENODEV:
                cfg = &mp->m_error_cfg[error_class][XFS_ERR_ENODEV];
                break;
        default:
                cfg = &mp->m_error_cfg[error_class][XFS_ERR_DEFAULT];
                break;
        }

        return cfg;
}