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 21 typedef 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 41 typedef enum { 42 ptr_explicit, 43 ptr_ext4_sb_info_offset, 44 ptr_ext4_super_block_offset, 45 } attr_ptr_t; 46 47 static const char proc_dirname[] = "fs/ext4"; 48 static struct proc_dir_entry *ext4_proc_root; 49 50 struct 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 61 static 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 73 static 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 86 static 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 } 102 103 static 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 } 118 119 static 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 } 134 135 static 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) \ 144 static 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) \ 154 static 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) \ 164 static 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) \ 196 static 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 206 207 EXT4_ATTR_FUNC(delayed_allocation_blocks, 0444); 208 EXT4_ATTR_FUNC(session_write_kbytes, 0444); 209 EXT4_ATTR_FUNC(lifetime_write_kbytes, 0444); 210 EXT4_ATTR_FUNC(reserved_clusters, 0644); 211 212 EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, inode_readahead, 213 ext4_sb_info, s_inode_readahead_blks); 214 EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal); 215 EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats); 216 EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan); 217 EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan); 218 EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs); 219 EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request); 220 EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc); 221 EXT4_RW_ATTR_SBI_UI(mb_max_inode_prealloc, s_mb_max_inode_prealloc); 222 EXT4_RW_ATTR_SBI_UI(extent_max_zeroout_kb, s_extent_max_zeroout_kb); 223 EXT4_ATTR(trigger_fs_error, 0200, trigger_test_error); 224 EXT4_RW_ATTR_SBI_UI(err_ratelimit_interval_ms, s_err_ratelimit_state.interval); 225 EXT4_RW_ATTR_SBI_UI(err_ratelimit_burst, s_err_ratelimit_state.burst); 226 EXT4_RW_ATTR_SBI_UI(warning_ratelimit_interval_ms, s_warning_ratelimit_state.interval); 227 EXT4_RW_ATTR_SBI_UI(warning_ratelimit_burst, s_warning_ratelimit_state.burst); 228 EXT4_RW_ATTR_SBI_UI(msg_ratelimit_interval_ms, s_msg_ratelimit_state.interval); 229 EXT4_RW_ATTR_SBI_UI(msg_ratelimit_burst, s_msg_ratelimit_state.burst); 230 #ifdef CONFIG_EXT4_DEBUG 231 EXT4_RW_ATTR_SBI_UL(simulate_fail, s_simulate_fail); 232 #endif 233 EXT4_RO_ATTR_SBI_ATOMIC(warning_count, s_warning_count); 234 EXT4_RO_ATTR_SBI_ATOMIC(msg_count, s_msg_count); 235 EXT4_RO_ATTR_ES_UI(errors_count, s_error_count); 236 EXT4_RO_ATTR_ES_U8(first_error_errcode, s_first_error_errcode); 237 EXT4_RO_ATTR_ES_U8(last_error_errcode, s_last_error_errcode); 238 EXT4_RO_ATTR_ES_UI(first_error_ino, s_first_error_ino); 239 EXT4_RO_ATTR_ES_UI(last_error_ino, s_last_error_ino); 240 EXT4_RO_ATTR_ES_U64(first_error_block, s_first_error_block); 241 EXT4_RO_ATTR_ES_U64(last_error_block, s_last_error_block); 242 EXT4_RO_ATTR_ES_UI(first_error_line, s_first_error_line); 243 EXT4_RO_ATTR_ES_UI(last_error_line, s_last_error_line); 244 EXT4_RO_ATTR_ES_STRING(first_error_func, s_first_error_func, 32); 245 EXT4_RO_ATTR_ES_STRING(last_error_func, s_last_error_func, 32); 246 EXT4_ATTR(first_error_time, 0444, first_error_time); 247 EXT4_ATTR(last_error_time, 0444, last_error_time); 248 EXT4_ATTR(journal_task, 0444, journal_task); 249 EXT4_RW_ATTR_SBI_UI(mb_prefetch, s_mb_prefetch); 250 EXT4_RW_ATTR_SBI_UI(mb_prefetch_limit, s_mb_prefetch_limit); 251 252 static unsigned int old_bump_val = 128; 253 EXT4_ATTR_PTR(max_writeback_mb_bump, 0444, pointer_ui, &old_bump_val); 254 255 static 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 }; 301 ATTRIBUTE_GROUPS(ext4); 302 303 /* Features this copy of ext4 supports */ 304 EXT4_ATTR_FEATURE(lazy_itable_init); 305 EXT4_ATTR_FEATURE(batched_discard); 306 EXT4_ATTR_FEATURE(meta_bg_resize); 307 #ifdef CONFIG_FS_ENCRYPTION 308 EXT4_ATTR_FEATURE(encryption); 309 EXT4_ATTR_FEATURE(test_dummy_encryption_v2); 310 #endif 311 #ifdef CONFIG_UNICODE 312 EXT4_ATTR_FEATURE(casefold); 313 #endif 314 #ifdef CONFIG_FS_VERITY 315 EXT4_ATTR_FEATURE(verity); 316 #endif 317 EXT4_ATTR_FEATURE(metadata_csum_seed); 318 EXT4_ATTR_FEATURE(fast_commit); 319 320 static 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 }; 338 ATTRIBUTE_GROUPS(ext4_feat); 339 340 static 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 } 352 353 static 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) 361 362 static 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 } 434 435 static 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 } 475 476 static 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 } 482 483 static const struct sysfs_ops ext4_attr_ops = { 484 .show = ext4_attr_show, 485 .store = ext4_attr_store, 486 }; 487 488 static struct kobj_type ext4_sb_ktype = { 489 .default_groups = ext4_groups, 490 .sysfs_ops = &ext4_attr_ops, 491 .release = ext4_sb_release, 492 }; 493 494 static 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 }; 499 500 static struct kobject *ext4_root; 501 502 static struct kobject *ext4_feat; 503 504 int 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 } 533 534 void 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 } 542 543 int __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; 564 565 feat_err: 566 kobject_put(ext4_feat); 567 ext4_feat = NULL; 568 root_err: 569 kobject_put(ext4_root); 570 ext4_root = NULL; 571 return ret; 572 } 573 574 void 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