linux/fs/ext4/sysfs.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 *  linux/fs/ext4/sysfs.c
   4 *
   5 * Copyright (C) 1992, 1993, 1994, 1995
   6 * Remy Card (card@masi.ibp.fr)
   7 * Theodore Ts'o (tytso@mit.edu)
   8 *
   9 */
  10
  11#include <linux/time.h>
  12#include <linux/fs.h>
  13#include <linux/seq_file.h>
  14#include <linux/slab.h>
  15#include <linux/proc_fs.h>
  16#include <linux/part_stat.h>
  17
  18#include "ext4.h"
  19#include "ext4_jbd2.h"
  20
  21typedef enum {
  22        attr_noop,
  23        attr_delayed_allocation_blocks,
  24        attr_session_write_kbytes,
  25        attr_lifetime_write_kbytes,
  26        attr_reserved_clusters,
  27        attr_inode_readahead,
  28        attr_trigger_test_error,
  29        attr_first_error_time,
  30        attr_last_error_time,
  31        attr_feature,
  32        attr_pointer_ui,
  33        attr_pointer_ul,
  34        attr_pointer_u64,
  35        attr_pointer_u8,
  36        attr_pointer_string,
  37        attr_pointer_atomic,
  38        attr_journal_task,
  39} attr_id_t;
  40
  41typedef enum {
  42        ptr_explicit,
  43        ptr_ext4_sb_info_offset,
  44        ptr_ext4_super_block_offset,
  45} attr_ptr_t;
  46
  47static const char proc_dirname[] = "fs/ext4";
  48static struct proc_dir_entry *ext4_proc_root;
  49
  50struct ext4_attr {
  51        struct attribute attr;
  52        short attr_id;
  53        short attr_ptr;
  54        unsigned short attr_size;
  55        union {
  56                int offset;
  57                void *explicit_ptr;
  58        } u;
  59};
  60
  61static ssize_t session_write_kbytes_show(struct ext4_sb_info *sbi, char *buf)
  62{
  63        struct super_block *sb = sbi->s_buddy_cache->i_sb;
  64
  65        if (!sb->s_bdev->bd_part)
  66                return snprintf(buf, PAGE_SIZE, "0\n");
  67        return snprintf(buf, PAGE_SIZE, "%lu\n",
  68                        (part_stat_read(sb->s_bdev->bd_part,
  69                                        sectors[STAT_WRITE]) -
  70                         sbi->s_sectors_written_start) >> 1);
  71}
  72
  73static ssize_t lifetime_write_kbytes_show(struct ext4_sb_info *sbi, char *buf)
  74{
  75        struct super_block *sb = sbi->s_buddy_cache->i_sb;
  76
  77        if (!sb->s_bdev->bd_part)
  78                return snprintf(buf, PAGE_SIZE, "0\n");
  79        return snprintf(buf, PAGE_SIZE, "%llu\n",
  80                        (unsigned long long)(sbi->s_kbytes_written +
  81                        ((part_stat_read(sb->s_bdev->bd_part,
  82                                         sectors[STAT_WRITE]) -
  83                          EXT4_SB(sb)->s_sectors_written_start) >> 1)));
  84}
  85
  86static ssize_t inode_readahead_blks_store(struct ext4_sb_info *sbi,
  87                                          const char *buf, size_t count)
  88{
  89        unsigned long t;
  90        int ret;
  91
  92        ret = kstrtoul(skip_spaces(buf), 0, &t);
  93        if (ret)
  94                return ret;
  95
  96        if (t && (!is_power_of_2(t) || t > 0x40000000))
  97                return -EINVAL;
  98
  99        sbi->s_inode_readahead_blks = t;
 100        return count;
 101}
 102
 103static ssize_t reserved_clusters_store(struct ext4_sb_info *sbi,
 104                                   const char *buf, size_t count)
 105{
 106        unsigned long long val;
 107        ext4_fsblk_t clusters = (ext4_blocks_count(sbi->s_es) >>
 108                                 sbi->s_cluster_bits);
 109        int ret;
 110
 111        ret = kstrtoull(skip_spaces(buf), 0, &val);
 112        if (ret || val >= clusters)
 113                return -EINVAL;
 114
 115        atomic64_set(&sbi->s_resv_clusters, val);
 116        return count;
 117}
 118
 119static ssize_t trigger_test_error(struct ext4_sb_info *sbi,
 120                                  const char *buf, size_t count)
 121{
 122        int len = count;
 123
 124        if (!capable(CAP_SYS_ADMIN))
 125                return -EPERM;
 126
 127        if (len && buf[len-1] == '\n')
 128                len--;
 129
 130        if (len)
 131                ext4_error(sbi->s_sb, "%.*s", len, buf);
 132        return count;
 133}
 134
 135static ssize_t journal_task_show(struct ext4_sb_info *sbi, char *buf)
 136{
 137        if (!sbi->s_journal)
 138                return snprintf(buf, PAGE_SIZE, "<none>\n");
 139        return snprintf(buf, PAGE_SIZE, "%d\n",
 140                        task_pid_vnr(sbi->s_journal->j_task));
 141}
 142
 143#define EXT4_ATTR(_name,_mode,_id)                                      \
 144static struct ext4_attr ext4_attr_##_name = {                           \
 145        .attr = {.name = __stringify(_name), .mode = _mode },           \
 146        .attr_id = attr_##_id,                                          \
 147}
 148
 149#define EXT4_ATTR_FUNC(_name,_mode)  EXT4_ATTR(_name,_mode,_name)
 150
 151#define EXT4_ATTR_FEATURE(_name)   EXT4_ATTR(_name, 0444, feature)
 152
 153#define EXT4_ATTR_OFFSET(_name,_mode,_id,_struct,_elname)       \
 154static struct ext4_attr ext4_attr_##_name = {                   \
 155        .attr = {.name = __stringify(_name), .mode = _mode },   \
 156        .attr_id = attr_##_id,                                  \
 157        .attr_ptr = ptr_##_struct##_offset,                     \
 158        .u = {                                                  \
 159                .offset = offsetof(struct _struct, _elname),\
 160        },                                                      \
 161}
 162
 163#define EXT4_ATTR_STRING(_name,_mode,_size,_struct,_elname)     \
 164static struct ext4_attr ext4_attr_##_name = {                   \
 165        .attr = {.name = __stringify(_name), .mode = _mode },   \
 166        .attr_id = attr_pointer_string,                         \
 167        .attr_size = _size,                                     \
 168        .attr_ptr = ptr_##_struct##_offset,                     \
 169        .u = {                                                  \
 170                .offset = offsetof(struct _struct, _elname),\
 171        },                                                      \
 172}
 173
 174#define EXT4_RO_ATTR_ES_UI(_name,_elname)                               \
 175        EXT4_ATTR_OFFSET(_name, 0444, pointer_ui, ext4_super_block, _elname)
 176
 177#define EXT4_RO_ATTR_ES_U8(_name,_elname)                               \
 178        EXT4_ATTR_OFFSET(_name, 0444, pointer_u8, ext4_super_block, _elname)
 179
 180#define EXT4_RO_ATTR_ES_U64(_name,_elname)                              \
 181        EXT4_ATTR_OFFSET(_name, 0444, pointer_u64, ext4_super_block, _elname)
 182
 183#define EXT4_RO_ATTR_ES_STRING(_name,_elname,_size)                     \
 184        EXT4_ATTR_STRING(_name, 0444, _size, ext4_super_block, _elname)
 185
 186#define EXT4_RW_ATTR_SBI_UI(_name,_elname)      \
 187        EXT4_ATTR_OFFSET(_name, 0644, pointer_ui, ext4_sb_info, _elname)
 188
 189#define EXT4_RW_ATTR_SBI_UL(_name,_elname)      \
 190        EXT4_ATTR_OFFSET(_name, 0644, pointer_ul, ext4_sb_info, _elname)
 191
 192#define EXT4_RO_ATTR_SBI_ATOMIC(_name,_elname)  \
 193        EXT4_ATTR_OFFSET(_name, 0444, pointer_atomic, ext4_sb_info, _elname)
 194
 195#define EXT4_ATTR_PTR(_name,_mode,_id,_ptr) \
 196static struct ext4_attr ext4_attr_##_name = {                   \
 197        .attr = {.name = __stringify(_name), .mode = _mode },   \
 198        .attr_id = attr_##_id,                                  \
 199        .attr_ptr = ptr_explicit,                               \
 200        .u = {                                                  \
 201                .explicit_ptr = _ptr,                           \
 202        },                                                      \
 203}
 204
 205#define ATTR_LIST(name) &ext4_attr_##name.attr
 206
 207EXT4_ATTR_FUNC(delayed_allocation_blocks, 0444);
 208EXT4_ATTR_FUNC(session_write_kbytes, 0444);
 209EXT4_ATTR_FUNC(lifetime_write_kbytes, 0444);
 210EXT4_ATTR_FUNC(reserved_clusters, 0644);
 211
 212EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, inode_readahead,
 213                 ext4_sb_info, s_inode_readahead_blks);
 214EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal);
 215EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats);
 216EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan);
 217EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan);
 218EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs);
 219EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request);
 220EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc);
 221EXT4_RW_ATTR_SBI_UI(mb_max_inode_prealloc, s_mb_max_inode_prealloc);
 222EXT4_RW_ATTR_SBI_UI(extent_max_zeroout_kb, s_extent_max_zeroout_kb);
 223EXT4_ATTR(trigger_fs_error, 0200, trigger_test_error);
 224EXT4_RW_ATTR_SBI_UI(err_ratelimit_interval_ms, s_err_ratelimit_state.interval);
 225EXT4_RW_ATTR_SBI_UI(err_ratelimit_burst, s_err_ratelimit_state.burst);
 226EXT4_RW_ATTR_SBI_UI(warning_ratelimit_interval_ms, s_warning_ratelimit_state.interval);
 227EXT4_RW_ATTR_SBI_UI(warning_ratelimit_burst, s_warning_ratelimit_state.burst);
 228EXT4_RW_ATTR_SBI_UI(msg_ratelimit_interval_ms, s_msg_ratelimit_state.interval);
 229EXT4_RW_ATTR_SBI_UI(msg_ratelimit_burst, s_msg_ratelimit_state.burst);
 230#ifdef CONFIG_EXT4_DEBUG
 231EXT4_RW_ATTR_SBI_UL(simulate_fail, s_simulate_fail);
 232#endif
 233EXT4_RO_ATTR_SBI_ATOMIC(warning_count, s_warning_count);
 234EXT4_RO_ATTR_SBI_ATOMIC(msg_count, s_msg_count);
 235EXT4_RO_ATTR_ES_UI(errors_count, s_error_count);
 236EXT4_RO_ATTR_ES_U8(first_error_errcode, s_first_error_errcode);
 237EXT4_RO_ATTR_ES_U8(last_error_errcode, s_last_error_errcode);
 238EXT4_RO_ATTR_ES_UI(first_error_ino, s_first_error_ino);
 239EXT4_RO_ATTR_ES_UI(last_error_ino, s_last_error_ino);
 240EXT4_RO_ATTR_ES_U64(first_error_block, s_first_error_block);
 241EXT4_RO_ATTR_ES_U64(last_error_block, s_last_error_block);
 242EXT4_RO_ATTR_ES_UI(first_error_line, s_first_error_line);
 243EXT4_RO_ATTR_ES_UI(last_error_line, s_last_error_line);
 244EXT4_RO_ATTR_ES_STRING(first_error_func, s_first_error_func, 32);
 245EXT4_RO_ATTR_ES_STRING(last_error_func, s_last_error_func, 32);
 246EXT4_ATTR(first_error_time, 0444, first_error_time);
 247EXT4_ATTR(last_error_time, 0444, last_error_time);
 248EXT4_ATTR(journal_task, 0444, journal_task);
 249EXT4_RW_ATTR_SBI_UI(mb_prefetch, s_mb_prefetch);
 250EXT4_RW_ATTR_SBI_UI(mb_prefetch_limit, s_mb_prefetch_limit);
 251
 252static unsigned int old_bump_val = 128;
 253EXT4_ATTR_PTR(max_writeback_mb_bump, 0444, pointer_ui, &old_bump_val);
 254
 255static struct attribute *ext4_attrs[] = {
 256        ATTR_LIST(delayed_allocation_blocks),
 257        ATTR_LIST(session_write_kbytes),
 258        ATTR_LIST(lifetime_write_kbytes),
 259        ATTR_LIST(reserved_clusters),
 260        ATTR_LIST(inode_readahead_blks),
 261        ATTR_LIST(inode_goal),
 262        ATTR_LIST(mb_stats),
 263        ATTR_LIST(mb_max_to_scan),
 264        ATTR_LIST(mb_min_to_scan),
 265        ATTR_LIST(mb_order2_req),
 266        ATTR_LIST(mb_stream_req),
 267        ATTR_LIST(mb_group_prealloc),
 268        ATTR_LIST(mb_max_inode_prealloc),
 269        ATTR_LIST(max_writeback_mb_bump),
 270        ATTR_LIST(extent_max_zeroout_kb),
 271        ATTR_LIST(trigger_fs_error),
 272        ATTR_LIST(err_ratelimit_interval_ms),
 273        ATTR_LIST(err_ratelimit_burst),
 274        ATTR_LIST(warning_ratelimit_interval_ms),
 275        ATTR_LIST(warning_ratelimit_burst),
 276        ATTR_LIST(msg_ratelimit_interval_ms),
 277        ATTR_LIST(msg_ratelimit_burst),
 278        ATTR_LIST(errors_count),
 279        ATTR_LIST(warning_count),
 280        ATTR_LIST(msg_count),
 281        ATTR_LIST(first_error_ino),
 282        ATTR_LIST(last_error_ino),
 283        ATTR_LIST(first_error_block),
 284        ATTR_LIST(last_error_block),
 285        ATTR_LIST(first_error_line),
 286        ATTR_LIST(last_error_line),
 287        ATTR_LIST(first_error_func),
 288        ATTR_LIST(last_error_func),
 289        ATTR_LIST(first_error_errcode),
 290        ATTR_LIST(last_error_errcode),
 291        ATTR_LIST(first_error_time),
 292        ATTR_LIST(last_error_time),
 293        ATTR_LIST(journal_task),
 294#ifdef CONFIG_EXT4_DEBUG
 295        ATTR_LIST(simulate_fail),
 296#endif
 297        ATTR_LIST(mb_prefetch),
 298        ATTR_LIST(mb_prefetch_limit),
 299        NULL,
 300};
 301ATTRIBUTE_GROUPS(ext4);
 302
 303/* Features this copy of ext4 supports */
 304EXT4_ATTR_FEATURE(lazy_itable_init);
 305EXT4_ATTR_FEATURE(batched_discard);
 306EXT4_ATTR_FEATURE(meta_bg_resize);
 307#ifdef CONFIG_FS_ENCRYPTION
 308EXT4_ATTR_FEATURE(encryption);
 309EXT4_ATTR_FEATURE(test_dummy_encryption_v2);
 310#endif
 311#ifdef CONFIG_UNICODE
 312EXT4_ATTR_FEATURE(casefold);
 313#endif
 314#ifdef CONFIG_FS_VERITY
 315EXT4_ATTR_FEATURE(verity);
 316#endif
 317EXT4_ATTR_FEATURE(metadata_csum_seed);
 318EXT4_ATTR_FEATURE(fast_commit);
 319
 320static struct attribute *ext4_feat_attrs[] = {
 321        ATTR_LIST(lazy_itable_init),
 322        ATTR_LIST(batched_discard),
 323        ATTR_LIST(meta_bg_resize),
 324#ifdef CONFIG_FS_ENCRYPTION
 325        ATTR_LIST(encryption),
 326        ATTR_LIST(test_dummy_encryption_v2),
 327#endif
 328#ifdef CONFIG_UNICODE
 329        ATTR_LIST(casefold),
 330#endif
 331#ifdef CONFIG_FS_VERITY
 332        ATTR_LIST(verity),
 333#endif
 334        ATTR_LIST(metadata_csum_seed),
 335        ATTR_LIST(fast_commit),
 336        NULL,
 337};
 338ATTRIBUTE_GROUPS(ext4_feat);
 339
 340static void *calc_ptr(struct ext4_attr *a, struct ext4_sb_info *sbi)
 341{
 342        switch (a->attr_ptr) {
 343        case ptr_explicit:
 344                return a->u.explicit_ptr;
 345        case ptr_ext4_sb_info_offset:
 346                return (void *) (((char *) sbi) + a->u.offset);
 347        case ptr_ext4_super_block_offset:
 348                return (void *) (((char *) sbi->s_es) + a->u.offset);
 349        }
 350        return NULL;
 351}
 352
 353static ssize_t __print_tstamp(char *buf, __le32 lo, __u8 hi)
 354{
 355        return snprintf(buf, PAGE_SIZE, "%lld\n",
 356                        ((time64_t)hi << 32) + le32_to_cpu(lo));
 357}
 358
 359#define print_tstamp(buf, es, tstamp) \
 360        __print_tstamp(buf, (es)->tstamp, (es)->tstamp ## _hi)
 361
 362static ssize_t ext4_attr_show(struct kobject *kobj,
 363                              struct attribute *attr, char *buf)
 364{
 365        struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
 366                                                s_kobj);
 367        struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
 368        void *ptr = calc_ptr(a, sbi);
 369
 370        switch (a->attr_id) {
 371        case attr_delayed_allocation_blocks:
 372                return snprintf(buf, PAGE_SIZE, "%llu\n",
 373                                (s64) EXT4_C2B(sbi,
 374                       percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
 375        case attr_session_write_kbytes:
 376                return session_write_kbytes_show(sbi, buf);
 377        case attr_lifetime_write_kbytes:
 378                return lifetime_write_kbytes_show(sbi, buf);
 379        case attr_reserved_clusters:
 380                return snprintf(buf, PAGE_SIZE, "%llu\n",
 381                                (unsigned long long)
 382                                atomic64_read(&sbi->s_resv_clusters));
 383        case attr_inode_readahead:
 384        case attr_pointer_ui:
 385                if (!ptr)
 386                        return 0;
 387                if (a->attr_ptr == ptr_ext4_super_block_offset)
 388                        return snprintf(buf, PAGE_SIZE, "%u\n",
 389                                        le32_to_cpup(ptr));
 390                else
 391                        return snprintf(buf, PAGE_SIZE, "%u\n",
 392                                        *((unsigned int *) ptr));
 393        case attr_pointer_ul:
 394                if (!ptr)
 395                        return 0;
 396                return snprintf(buf, PAGE_SIZE, "%lu\n",
 397                                *((unsigned long *) ptr));
 398        case attr_pointer_u8:
 399                if (!ptr)
 400                        return 0;
 401                return snprintf(buf, PAGE_SIZE, "%u\n",
 402                                *((unsigned char *) ptr));
 403        case attr_pointer_u64:
 404                if (!ptr)
 405                        return 0;
 406                if (a->attr_ptr == ptr_ext4_super_block_offset)
 407                        return snprintf(buf, PAGE_SIZE, "%llu\n",
 408                                        le64_to_cpup(ptr));
 409                else
 410                        return snprintf(buf, PAGE_SIZE, "%llu\n",
 411                                        *((unsigned long long *) ptr));
 412        case attr_pointer_string:
 413                if (!ptr)
 414                        return 0;
 415                return snprintf(buf, PAGE_SIZE, "%.*s\n", a->attr_size,
 416                                (char *) ptr);
 417        case attr_pointer_atomic:
 418                if (!ptr)
 419                        return 0;
 420                return snprintf(buf, PAGE_SIZE, "%d\n",
 421                                atomic_read((atomic_t *) ptr));
 422        case attr_feature:
 423                return snprintf(buf, PAGE_SIZE, "supported\n");
 424        case attr_first_error_time:
 425                return print_tstamp(buf, sbi->s_es, s_first_error_time);
 426        case attr_last_error_time:
 427                return print_tstamp(buf, sbi->s_es, s_last_error_time);
 428        case attr_journal_task:
 429                return journal_task_show(sbi, buf);
 430        }
 431
 432        return 0;
 433}
 434
 435static ssize_t ext4_attr_store(struct kobject *kobj,
 436                               struct attribute *attr,
 437                               const char *buf, size_t len)
 438{
 439        struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
 440                                                s_kobj);
 441        struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
 442        void *ptr = calc_ptr(a, sbi);
 443        unsigned long t;
 444        int ret;
 445
 446        switch (a->attr_id) {
 447        case attr_reserved_clusters:
 448                return reserved_clusters_store(sbi, buf, len);
 449        case attr_pointer_ui:
 450                if (!ptr)
 451                        return 0;
 452                ret = kstrtoul(skip_spaces(buf), 0, &t);
 453                if (ret)
 454                        return ret;
 455                if (a->attr_ptr == ptr_ext4_super_block_offset)
 456                        *((__le32 *) ptr) = cpu_to_le32(t);
 457                else
 458                        *((unsigned int *) ptr) = t;
 459                return len;
 460        case attr_pointer_ul:
 461                if (!ptr)
 462                        return 0;
 463                ret = kstrtoul(skip_spaces(buf), 0, &t);
 464                if (ret)
 465                        return ret;
 466                *((unsigned long *) ptr) = t;
 467                return len;
 468        case attr_inode_readahead:
 469                return inode_readahead_blks_store(sbi, buf, len);
 470        case attr_trigger_test_error:
 471                return trigger_test_error(sbi, buf, len);
 472        }
 473        return 0;
 474}
 475
 476static void ext4_sb_release(struct kobject *kobj)
 477{
 478        struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
 479                                                s_kobj);
 480        complete(&sbi->s_kobj_unregister);
 481}
 482
 483static const struct sysfs_ops ext4_attr_ops = {
 484        .show   = ext4_attr_show,
 485        .store  = ext4_attr_store,
 486};
 487
 488static struct kobj_type ext4_sb_ktype = {
 489        .default_groups = ext4_groups,
 490        .sysfs_ops      = &ext4_attr_ops,
 491        .release        = ext4_sb_release,
 492};
 493
 494static struct kobj_type ext4_feat_ktype = {
 495        .default_groups = ext4_feat_groups,
 496        .sysfs_ops      = &ext4_attr_ops,
 497        .release        = (void (*)(struct kobject *))kfree,
 498};
 499
 500static struct kobject *ext4_root;
 501
 502static struct kobject *ext4_feat;
 503
 504int ext4_register_sysfs(struct super_block *sb)
 505{
 506        struct ext4_sb_info *sbi = EXT4_SB(sb);
 507        int err;
 508
 509        init_completion(&sbi->s_kobj_unregister);
 510        err = kobject_init_and_add(&sbi->s_kobj, &ext4_sb_ktype, ext4_root,
 511                                   "%s", sb->s_id);
 512        if (err) {
 513                kobject_put(&sbi->s_kobj);
 514                wait_for_completion(&sbi->s_kobj_unregister);
 515                return err;
 516        }
 517
 518        if (ext4_proc_root)
 519                sbi->s_proc = proc_mkdir(sb->s_id, ext4_proc_root);
 520        if (sbi->s_proc) {
 521                proc_create_single_data("options", S_IRUGO, sbi->s_proc,
 522                                ext4_seq_options_show, sb);
 523                proc_create_single_data("es_shrinker_info", S_IRUGO,
 524                                sbi->s_proc, ext4_seq_es_shrinker_info_show,
 525                                sb);
 526                proc_create_single_data("fc_info", 0444, sbi->s_proc,
 527                                        ext4_fc_info_show, sb);
 528                proc_create_seq_data("mb_groups", S_IRUGO, sbi->s_proc,
 529                                &ext4_mb_seq_groups_ops, sb);
 530        }
 531        return 0;
 532}
 533
 534void ext4_unregister_sysfs(struct super_block *sb)
 535{
 536        struct ext4_sb_info *sbi = EXT4_SB(sb);
 537
 538        if (sbi->s_proc)
 539                remove_proc_subtree(sb->s_id, ext4_proc_root);
 540        kobject_del(&sbi->s_kobj);
 541}
 542
 543int __init ext4_init_sysfs(void)
 544{
 545        int ret;
 546
 547        ext4_root = kobject_create_and_add("ext4", fs_kobj);
 548        if (!ext4_root)
 549                return -ENOMEM;
 550
 551        ext4_feat = kzalloc(sizeof(*ext4_feat), GFP_KERNEL);
 552        if (!ext4_feat) {
 553                ret = -ENOMEM;
 554                goto root_err;
 555        }
 556
 557        ret = kobject_init_and_add(ext4_feat, &ext4_feat_ktype,
 558                                   ext4_root, "features");
 559        if (ret)
 560                goto feat_err;
 561
 562        ext4_proc_root = proc_mkdir(proc_dirname, NULL);
 563        return ret;
 564
 565feat_err:
 566        kobject_put(ext4_feat);
 567        ext4_feat = NULL;
 568root_err:
 569        kobject_put(ext4_root);
 570        ext4_root = NULL;
 571        return ret;
 572}
 573
 574void ext4_exit_sysfs(void)
 575{
 576        kobject_put(ext4_feat);
 577        ext4_feat = NULL;
 578        kobject_put(ext4_root);
 579        ext4_root = NULL;
 580        remove_proc_entry(proc_dirname, NULL);
 581        ext4_proc_root = NULL;
 582}
 583
 584