root/fs/ext4/sysfs.c
// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/fs/ext4/sysfs.c
 *
 * Copyright (C) 1992, 1993, 1994, 1995
 * Remy Card (card@masi.ibp.fr)
 * Theodore Ts'o (tytso@mit.edu)
 *
 */

#include <linux/time.h>
#include <linux/fs.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/proc_fs.h>
#include <linux/part_stat.h>

#include "ext4.h"
#include "ext4_jbd2.h"

typedef enum {
        attr_noop,
        attr_delayed_allocation_blocks,
        attr_session_write_kbytes,
        attr_lifetime_write_kbytes,
        attr_reserved_clusters,
        attr_sra_exceeded_retry_limit,
        attr_inode_readahead,
        attr_trigger_test_error,
        attr_first_error_time,
        attr_last_error_time,
        attr_clusters_in_group,
        attr_mb_order,
        attr_feature,
        attr_pointer_pi,
        attr_pointer_ui,
        attr_pointer_ul,
        attr_pointer_u64,
        attr_pointer_u8,
        attr_pointer_string,
        attr_pointer_atomic,
        attr_journal_task,
        attr_err_report_sec,
} attr_id_t;

typedef enum {
        ptr_explicit,
        ptr_ext4_sb_info_offset,
        ptr_ext4_super_block_offset,
} attr_ptr_t;

static const char proc_dirname[] = "fs/ext4";
static struct proc_dir_entry *ext4_proc_root;

struct ext4_attr {
        struct attribute attr;
        short attr_id;
        short attr_ptr;
        unsigned short attr_size;
        union {
                int offset;
                void *explicit_ptr;
        } u;
};

static ssize_t session_write_kbytes_show(struct ext4_sb_info *sbi, char *buf)
{
        struct super_block *sb = sbi->s_buddy_cache->i_sb;

        return sysfs_emit(buf, "%lu\n",
                        (part_stat_read(sb->s_bdev, sectors[STAT_WRITE]) -
                         sbi->s_sectors_written_start) >> 1);
}

static ssize_t lifetime_write_kbytes_show(struct ext4_sb_info *sbi, char *buf)
{
        struct super_block *sb = sbi->s_buddy_cache->i_sb;

        return sysfs_emit(buf, "%llu\n",
                        (unsigned long long)(sbi->s_kbytes_written +
                        ((part_stat_read(sb->s_bdev, sectors[STAT_WRITE]) -
                          EXT4_SB(sb)->s_sectors_written_start) >> 1)));
}

static ssize_t inode_readahead_blks_store(struct ext4_sb_info *sbi,
                                          const char *buf, size_t count)
{
        unsigned long t;
        int ret;

        ret = kstrtoul(skip_spaces(buf), 0, &t);
        if (ret)
                return ret;

        if (t && (!is_power_of_2(t) || t > 0x40000000))
                return -EINVAL;

        sbi->s_inode_readahead_blks = t;
        return count;
}

static ssize_t reserved_clusters_store(struct ext4_sb_info *sbi,
                                   const char *buf, size_t count)
{
        unsigned long long val;
        ext4_fsblk_t clusters = (ext4_blocks_count(sbi->s_es) >>
                                 sbi->s_cluster_bits);
        int ret;

        ret = kstrtoull(skip_spaces(buf), 0, &val);
        if (ret || val >= clusters || (s64)val < 0)
                return -EINVAL;

        atomic64_set(&sbi->s_resv_clusters, val);
        return count;
}

static ssize_t trigger_test_error(struct ext4_sb_info *sbi,
                                  const char *buf, size_t count)
{
        int len = count;

        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;

        if (len && buf[len-1] == '\n')
                len--;

        if (len)
                ext4_error(sbi->s_sb, "%.*s", len, buf);
        return count;
}

static ssize_t err_report_sec_store(struct ext4_sb_info *sbi,
                                    const char *buf, size_t count)
{
        unsigned long t;
        int ret;

        ret = kstrtoul(skip_spaces(buf), 0, &t);
        if (ret)
                return ret;

        /*the maximum time interval must not exceed one year.*/
        if (t > (365*24*60*60))
                return -EINVAL;

        if (sbi->s_err_report_sec == t)         /*nothing to do*/
                goto out;
        else if (!sbi->s_err_report_sec && t) {
                timer_setup(&sbi->s_err_report, print_daily_error_info, 0);
        } else if (sbi->s_err_report_sec && !t) {
                timer_delete_sync(&sbi->s_err_report);
                goto out;
        }

        sbi->s_err_report_sec = t;
        mod_timer(&sbi->s_err_report, jiffies + secs_to_jiffies(sbi->s_err_report_sec));

out:
        return count;
}

static ssize_t journal_task_show(struct ext4_sb_info *sbi, char *buf)
{
        if (!sbi->s_journal)
                return sysfs_emit(buf, "<none>\n");
        return sysfs_emit(buf, "%d\n",
                        task_pid_vnr(sbi->s_journal->j_task));
}

#define EXT4_ATTR(_name,_mode,_id)                                      \
static struct ext4_attr ext4_attr_##_name = {                           \
        .attr = {.name = __stringify(_name), .mode = _mode },           \
        .attr_id = attr_##_id,                                          \
}

#define EXT4_ATTR_FUNC(_name,_mode)  EXT4_ATTR(_name,_mode,_name)

#define EXT4_ATTR_FEATURE(_name)   EXT4_ATTR(_name, 0444, feature)

#define EXT4_ATTR_OFFSET(_name,_mode,_id,_struct,_elname)       \
static struct ext4_attr ext4_attr_##_name = {                   \
        .attr = {.name = __stringify(_name), .mode = _mode },   \
        .attr_id = attr_##_id,                                  \
        .attr_ptr = ptr_##_struct##_offset,                     \
        .u = {                                                  \
                .offset = offsetof(struct _struct, _elname),\
        },                                                      \
}

#define EXT4_ATTR_STRING(_name,_mode,_size,_struct,_elname)     \
static struct ext4_attr ext4_attr_##_name = {                   \
        .attr = {.name = __stringify(_name), .mode = _mode },   \
        .attr_id = attr_pointer_string,                         \
        .attr_size = _size,                                     \
        .attr_ptr = ptr_##_struct##_offset,                     \
        .u = {                                                  \
                .offset = offsetof(struct _struct, _elname),\
        },                                                      \
}

#define EXT4_RO_ATTR_ES_UI(_name,_elname)                               \
        EXT4_ATTR_OFFSET(_name, 0444, pointer_ui, ext4_super_block, _elname)

#define EXT4_RO_ATTR_ES_U8(_name,_elname)                               \
        EXT4_ATTR_OFFSET(_name, 0444, pointer_u8, ext4_super_block, _elname)

#define EXT4_RO_ATTR_ES_U64(_name,_elname)                              \
        EXT4_ATTR_OFFSET(_name, 0444, pointer_u64, ext4_super_block, _elname)

#define EXT4_RO_ATTR_ES_STRING(_name,_elname,_size)                     \
        EXT4_ATTR_STRING(_name, 0444, _size, ext4_super_block, _elname)

#define EXT4_RW_ATTR_SBI_PI(_name,_elname)      \
        EXT4_ATTR_OFFSET(_name, 0644, pointer_pi, ext4_sb_info, _elname)

#define EXT4_RW_ATTR_SBI_UI(_name,_elname)      \
        EXT4_ATTR_OFFSET(_name, 0644, pointer_ui, ext4_sb_info, _elname)

#define EXT4_RW_ATTR_SBI_UL(_name,_elname)      \
        EXT4_ATTR_OFFSET(_name, 0644, pointer_ul, ext4_sb_info, _elname)

#define EXT4_RO_ATTR_SBI_ATOMIC(_name,_elname)  \
        EXT4_ATTR_OFFSET(_name, 0444, pointer_atomic, ext4_sb_info, _elname)

#define EXT4_ATTR_PTR(_name,_mode,_id,_ptr) \
static struct ext4_attr ext4_attr_##_name = {                   \
        .attr = {.name = __stringify(_name), .mode = _mode },   \
        .attr_id = attr_##_id,                                  \
        .attr_ptr = ptr_explicit,                               \
        .u = {                                                  \
                .explicit_ptr = _ptr,                           \
        },                                                      \
}

#define ATTR_LIST(name) &ext4_attr_##name.attr

EXT4_ATTR_FUNC(delayed_allocation_blocks, 0444);
EXT4_ATTR_FUNC(session_write_kbytes, 0444);
EXT4_ATTR_FUNC(lifetime_write_kbytes, 0444);
EXT4_ATTR_FUNC(reserved_clusters, 0644);
EXT4_ATTR_FUNC(sra_exceeded_retry_limit, 0444);

EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, inode_readahead,
                 ext4_sb_info, s_inode_readahead_blks);
EXT4_ATTR_OFFSET(mb_group_prealloc, 0644, clusters_in_group,
                 ext4_sb_info, s_mb_group_prealloc);
EXT4_ATTR_OFFSET(mb_best_avail_max_trim_order, 0644, mb_order,
                 ext4_sb_info, s_mb_best_avail_max_trim_order);
EXT4_ATTR_OFFSET(err_report_sec, 0644, err_report_sec, ext4_sb_info, s_err_report_sec);
EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal);
EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats);
EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan);
EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan);
EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs);
EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request);
EXT4_RW_ATTR_SBI_UI(mb_max_linear_groups, s_mb_max_linear_groups);
EXT4_RW_ATTR_SBI_UI(extent_max_zeroout_kb, s_extent_max_zeroout_kb);
EXT4_ATTR(trigger_fs_error, 0200, trigger_test_error);
EXT4_RW_ATTR_SBI_PI(err_ratelimit_interval_ms, s_err_ratelimit_state.interval);
EXT4_RW_ATTR_SBI_PI(err_ratelimit_burst, s_err_ratelimit_state.burst);
EXT4_RW_ATTR_SBI_PI(warning_ratelimit_interval_ms, s_warning_ratelimit_state.interval);
EXT4_RW_ATTR_SBI_PI(warning_ratelimit_burst, s_warning_ratelimit_state.burst);
EXT4_RW_ATTR_SBI_PI(msg_ratelimit_interval_ms, s_msg_ratelimit_state.interval);
EXT4_RW_ATTR_SBI_PI(msg_ratelimit_burst, s_msg_ratelimit_state.burst);
#ifdef CONFIG_EXT4_DEBUG
EXT4_RW_ATTR_SBI_UL(simulate_fail, s_simulate_fail);
#endif
EXT4_RO_ATTR_SBI_ATOMIC(warning_count, s_warning_count);
EXT4_RO_ATTR_SBI_ATOMIC(msg_count, s_msg_count);
EXT4_RO_ATTR_ES_UI(errors_count, s_error_count);
EXT4_RO_ATTR_ES_U8(first_error_errcode, s_first_error_errcode);
EXT4_RO_ATTR_ES_U8(last_error_errcode, s_last_error_errcode);
EXT4_RO_ATTR_ES_UI(first_error_ino, s_first_error_ino);
EXT4_RO_ATTR_ES_UI(last_error_ino, s_last_error_ino);
EXT4_RO_ATTR_ES_U64(first_error_block, s_first_error_block);
EXT4_RO_ATTR_ES_U64(last_error_block, s_last_error_block);
EXT4_RO_ATTR_ES_UI(first_error_line, s_first_error_line);
EXT4_RO_ATTR_ES_UI(last_error_line, s_last_error_line);
EXT4_RO_ATTR_ES_STRING(first_error_func, s_first_error_func, 32);
EXT4_RO_ATTR_ES_STRING(last_error_func, s_last_error_func, 32);
EXT4_ATTR(first_error_time, 0444, first_error_time);
EXT4_ATTR(last_error_time, 0444, last_error_time);
EXT4_ATTR(journal_task, 0444, journal_task);
EXT4_RW_ATTR_SBI_UI(mb_prefetch, s_mb_prefetch);
EXT4_RW_ATTR_SBI_UI(mb_prefetch_limit, s_mb_prefetch_limit);
EXT4_RW_ATTR_SBI_UL(last_trim_minblks, s_last_trim_minblks);
EXT4_RW_ATTR_SBI_UI(sb_update_sec, s_sb_update_sec);
EXT4_RW_ATTR_SBI_UI(sb_update_kb, s_sb_update_kb);

static unsigned int old_bump_val = 128;
EXT4_ATTR_PTR(max_writeback_mb_bump, 0444, pointer_ui, &old_bump_val);

static struct attribute *ext4_attrs[] = {
        ATTR_LIST(delayed_allocation_blocks),
        ATTR_LIST(session_write_kbytes),
        ATTR_LIST(lifetime_write_kbytes),
        ATTR_LIST(reserved_clusters),
        ATTR_LIST(sra_exceeded_retry_limit),
        ATTR_LIST(inode_readahead_blks),
        ATTR_LIST(inode_goal),
        ATTR_LIST(mb_stats),
        ATTR_LIST(mb_max_to_scan),
        ATTR_LIST(mb_min_to_scan),
        ATTR_LIST(mb_order2_req),
        ATTR_LIST(mb_stream_req),
        ATTR_LIST(mb_group_prealloc),
        ATTR_LIST(mb_max_linear_groups),
        ATTR_LIST(max_writeback_mb_bump),
        ATTR_LIST(extent_max_zeroout_kb),
        ATTR_LIST(trigger_fs_error),
        ATTR_LIST(err_ratelimit_interval_ms),
        ATTR_LIST(err_ratelimit_burst),
        ATTR_LIST(warning_ratelimit_interval_ms),
        ATTR_LIST(warning_ratelimit_burst),
        ATTR_LIST(msg_ratelimit_interval_ms),
        ATTR_LIST(msg_ratelimit_burst),
        ATTR_LIST(mb_best_avail_max_trim_order),
        ATTR_LIST(errors_count),
        ATTR_LIST(warning_count),
        ATTR_LIST(msg_count),
        ATTR_LIST(first_error_ino),
        ATTR_LIST(last_error_ino),
        ATTR_LIST(first_error_block),
        ATTR_LIST(last_error_block),
        ATTR_LIST(first_error_line),
        ATTR_LIST(last_error_line),
        ATTR_LIST(first_error_func),
        ATTR_LIST(last_error_func),
        ATTR_LIST(first_error_errcode),
        ATTR_LIST(last_error_errcode),
        ATTR_LIST(first_error_time),
        ATTR_LIST(last_error_time),
        ATTR_LIST(journal_task),
#ifdef CONFIG_EXT4_DEBUG
        ATTR_LIST(simulate_fail),
#endif
        ATTR_LIST(mb_prefetch),
        ATTR_LIST(mb_prefetch_limit),
        ATTR_LIST(last_trim_minblks),
        ATTR_LIST(sb_update_sec),
        ATTR_LIST(sb_update_kb),
        ATTR_LIST(err_report_sec),
        NULL,
};
ATTRIBUTE_GROUPS(ext4);

/* Features this copy of ext4 supports */
EXT4_ATTR_FEATURE(lazy_itable_init);
EXT4_ATTR_FEATURE(batched_discard);
EXT4_ATTR_FEATURE(meta_bg_resize);
#ifdef CONFIG_FS_ENCRYPTION
EXT4_ATTR_FEATURE(encryption);
EXT4_ATTR_FEATURE(test_dummy_encryption_v2);
#endif
#if IS_ENABLED(CONFIG_UNICODE)
EXT4_ATTR_FEATURE(casefold);
#endif
#ifdef CONFIG_FS_VERITY
EXT4_ATTR_FEATURE(verity);
#endif
EXT4_ATTR_FEATURE(metadata_csum_seed);
EXT4_ATTR_FEATURE(fast_commit);
#if IS_ENABLED(CONFIG_UNICODE) && defined(CONFIG_FS_ENCRYPTION)
EXT4_ATTR_FEATURE(encrypted_casefold);
#endif
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
EXT4_ATTR_FEATURE(blocksize_gt_pagesize);
#endif

static struct attribute *ext4_feat_attrs[] = {
        ATTR_LIST(lazy_itable_init),
        ATTR_LIST(batched_discard),
        ATTR_LIST(meta_bg_resize),
#ifdef CONFIG_FS_ENCRYPTION
        ATTR_LIST(encryption),
        ATTR_LIST(test_dummy_encryption_v2),
#endif
#if IS_ENABLED(CONFIG_UNICODE)
        ATTR_LIST(casefold),
#endif
#ifdef CONFIG_FS_VERITY
        ATTR_LIST(verity),
#endif
        ATTR_LIST(metadata_csum_seed),
        ATTR_LIST(fast_commit),
#if IS_ENABLED(CONFIG_UNICODE) && defined(CONFIG_FS_ENCRYPTION)
        ATTR_LIST(encrypted_casefold),
#endif
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
        ATTR_LIST(blocksize_gt_pagesize),
#endif
        NULL,
};
ATTRIBUTE_GROUPS(ext4_feat);

static void *calc_ptr(struct ext4_attr *a, struct ext4_sb_info *sbi)
{
        switch (a->attr_ptr) {
        case ptr_explicit:
                return a->u.explicit_ptr;
        case ptr_ext4_sb_info_offset:
                return (void *) (((char *) sbi) + a->u.offset);
        case ptr_ext4_super_block_offset:
                return (void *) (((char *) sbi->s_es) + a->u.offset);
        }
        return NULL;
}

static ssize_t __print_tstamp(char *buf, __le32 lo, __u8 hi)
{
        return sysfs_emit(buf, "%lld\n",
                        ((time64_t)hi << 32) + le32_to_cpu(lo));
}

#define print_tstamp(buf, es, tstamp) \
        __print_tstamp(buf, (es)->tstamp, (es)->tstamp ## _hi)

static ssize_t ext4_generic_attr_show(struct ext4_attr *a,
                                      struct ext4_sb_info *sbi, char *buf)
{
        void *ptr = calc_ptr(a, sbi);

        if (!ptr)
                return 0;

        switch (a->attr_id) {
        case attr_inode_readahead:
        case attr_clusters_in_group:
        case attr_mb_order:
        case attr_pointer_pi:
        case attr_pointer_ui:
                if (a->attr_ptr == ptr_ext4_super_block_offset)
                        return sysfs_emit(buf, "%u\n", le32_to_cpup(ptr));
                return sysfs_emit(buf, "%u\n", *((unsigned int *) ptr));
        case attr_pointer_ul:
        case attr_err_report_sec:
                return sysfs_emit(buf, "%lu\n", *((unsigned long *) ptr));
        case attr_pointer_u8:
                return sysfs_emit(buf, "%u\n", *((unsigned char *) ptr));
        case attr_pointer_u64:
                if (a->attr_ptr == ptr_ext4_super_block_offset)
                        return sysfs_emit(buf, "%llu\n", le64_to_cpup(ptr));
                return sysfs_emit(buf, "%llu\n", *((unsigned long long *) ptr));
        case attr_pointer_string:
                return sysfs_emit(buf, "%.*s\n", a->attr_size, (char *) ptr);
        case attr_pointer_atomic:
                return sysfs_emit(buf, "%d\n", atomic_read((atomic_t *) ptr));
        }
        return 0;
}

static ssize_t ext4_attr_show(struct kobject *kobj,
                              struct attribute *attr, char *buf)
{
        struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
                                                s_kobj);
        struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);

        switch (a->attr_id) {
        case attr_delayed_allocation_blocks:
                return sysfs_emit(buf, "%llu\n",
                                (s64) EXT4_C2B(sbi,
                       percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
        case attr_session_write_kbytes:
                return session_write_kbytes_show(sbi, buf);
        case attr_lifetime_write_kbytes:
                return lifetime_write_kbytes_show(sbi, buf);
        case attr_reserved_clusters:
                return sysfs_emit(buf, "%llu\n",
                                (unsigned long long)
                                atomic64_read(&sbi->s_resv_clusters));
        case attr_sra_exceeded_retry_limit:
                return sysfs_emit(buf, "%llu\n",
                                (unsigned long long)
                        percpu_counter_sum(&sbi->s_sra_exceeded_retry_limit));
        case attr_feature:
                return sysfs_emit(buf, "supported\n");
        case attr_first_error_time:
                return print_tstamp(buf, sbi->s_es, s_first_error_time);
        case attr_last_error_time:
                return print_tstamp(buf, sbi->s_es, s_last_error_time);
        case attr_journal_task:
                return journal_task_show(sbi, buf);
        default:
                return ext4_generic_attr_show(a, sbi, buf);
        }
}

static ssize_t ext4_generic_attr_store(struct ext4_attr *a,
                                       struct ext4_sb_info *sbi,
                                       const char *buf, size_t len)
{
        int ret;
        unsigned int t;
        unsigned long lt;
        void *ptr = calc_ptr(a, sbi);

        if (!ptr)
                return 0;

        switch (a->attr_id) {
        case attr_pointer_pi:
                ret = kstrtouint(skip_spaces(buf), 0, &t);
                if (ret)
                        return ret;
                if ((int)t < 0)
                        return -EINVAL;
                *((unsigned int *) ptr) = t;
                return len;
        case attr_pointer_ui:
                ret = kstrtouint(skip_spaces(buf), 0, &t);
                if (ret)
                        return ret;
                if (a->attr_ptr == ptr_ext4_super_block_offset)
                        *((__le32 *) ptr) = cpu_to_le32(t);
                else
                        *((unsigned int *) ptr) = t;
                return len;
        case attr_mb_order:
                ret = kstrtouint(skip_spaces(buf), 0, &t);
                if (ret)
                        return ret;
                if (t > 64)
                        return -EINVAL;
                *((unsigned int *) ptr) = t;
                return len;
        case attr_clusters_in_group:
                ret = kstrtouint(skip_spaces(buf), 0, &t);
                if (ret)
                        return ret;
                if (t > sbi->s_clusters_per_group)
                        return -EINVAL;
                *((unsigned int *) ptr) = t;
                return len;
        case attr_pointer_ul:
                ret = kstrtoul(skip_spaces(buf), 0, &lt);
                if (ret)
                        return ret;
                *((unsigned long *) ptr) = lt;
                return len;
        }
        return 0;
}

static ssize_t ext4_attr_store(struct kobject *kobj,
                               struct attribute *attr,
                               const char *buf, size_t len)
{
        struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
                                                s_kobj);
        struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);

        switch (a->attr_id) {
        case attr_reserved_clusters:
                return reserved_clusters_store(sbi, buf, len);
        case attr_inode_readahead:
                return inode_readahead_blks_store(sbi, buf, len);
        case attr_trigger_test_error:
                return trigger_test_error(sbi, buf, len);
        case attr_err_report_sec:
                return err_report_sec_store(sbi, buf, len);
        default:
                return ext4_generic_attr_store(a, sbi, buf, len);
        }
}

static void ext4_sb_release(struct kobject *kobj)
{
        struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
                                                s_kobj);
        complete(&sbi->s_kobj_unregister);
}

static void ext4_feat_release(struct kobject *kobj)
{
        kfree(kobj);
}

static const struct sysfs_ops ext4_attr_ops = {
        .show   = ext4_attr_show,
        .store  = ext4_attr_store,
};

static const struct kobj_type ext4_sb_ktype = {
        .default_groups = ext4_groups,
        .sysfs_ops      = &ext4_attr_ops,
        .release        = ext4_sb_release,
};

static const struct kobj_type ext4_feat_ktype = {
        .default_groups = ext4_feat_groups,
        .sysfs_ops      = &ext4_attr_ops,
        .release        = ext4_feat_release,
};

void ext4_notify_error_sysfs(struct ext4_sb_info *sbi)
{
        mutex_lock(&sbi->s_error_notify_mutex);
        if (sbi->s_kobj.state_in_sysfs)
                sysfs_notify(&sbi->s_kobj, NULL, "errors_count");
        mutex_unlock(&sbi->s_error_notify_mutex);
}

static struct kobject *ext4_root;

static struct kobject *ext4_feat;

int ext4_register_sysfs(struct super_block *sb)
{
        struct ext4_sb_info *sbi = EXT4_SB(sb);
        int err;

        init_completion(&sbi->s_kobj_unregister);
        mutex_lock(&sbi->s_error_notify_mutex);
        err = kobject_init_and_add(&sbi->s_kobj, &ext4_sb_ktype, ext4_root,
                                   "%s", sb->s_id);
        mutex_unlock(&sbi->s_error_notify_mutex);
        if (err) {
                kobject_put(&sbi->s_kobj);
                wait_for_completion(&sbi->s_kobj_unregister);
                return err;
        }

        if (ext4_proc_root)
                sbi->s_proc = proc_mkdir(sb->s_id, ext4_proc_root);
        if (sbi->s_proc) {
                proc_create_single_data("options", S_IRUGO, sbi->s_proc,
                                ext4_seq_options_show, sb);
                proc_create_single_data("es_shrinker_info", S_IRUGO,
                                sbi->s_proc, ext4_seq_es_shrinker_info_show,
                                sb);
                proc_create_single_data("fc_info", 0444, sbi->s_proc,
                                        ext4_fc_info_show, sb);
                proc_create_seq_data("mb_groups", S_IRUGO, sbi->s_proc,
                                &ext4_mb_seq_groups_ops, sb);
                proc_create_single_data("mb_stats", 0444, sbi->s_proc,
                                ext4_seq_mb_stats_show, sb);
                proc_create_seq_data("mb_structs_summary", 0444, sbi->s_proc,
                                &ext4_mb_seq_structs_summary_ops, sb);
        }
        return 0;
}

void ext4_unregister_sysfs(struct super_block *sb)
{
        struct ext4_sb_info *sbi = EXT4_SB(sb);

        if (sbi->s_proc)
                remove_proc_subtree(sb->s_id, ext4_proc_root);

        mutex_lock(&sbi->s_error_notify_mutex);
        kobject_del(&sbi->s_kobj);
        mutex_unlock(&sbi->s_error_notify_mutex);
}

int __init ext4_init_sysfs(void)
{
        int ret;

        ext4_root = kobject_create_and_add("ext4", fs_kobj);
        if (!ext4_root)
                return -ENOMEM;

        ext4_feat = kzalloc_obj(*ext4_feat);
        if (!ext4_feat) {
                ret = -ENOMEM;
                goto root_err;
        }

        ret = kobject_init_and_add(ext4_feat, &ext4_feat_ktype,
                                   ext4_root, "features");
        if (ret)
                goto feat_err;

        ext4_proc_root = proc_mkdir(proc_dirname, NULL);
        return ret;

feat_err:
        kobject_put(ext4_feat);
        ext4_feat = NULL;
root_err:
        kobject_put(ext4_root);
        ext4_root = NULL;
        return ret;
}

void ext4_exit_sysfs(void)
{
        kobject_put(ext4_feat);
        ext4_feat = NULL;
        kobject_put(ext4_root);
        ext4_root = NULL;
        remove_proc_entry(proc_dirname, NULL);
        ext4_proc_root = NULL;
}