fs/ext4/sysfs.c

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