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); 318 319 static struct attribute *ext4_feat_attrs[] = { 320 ATTR_LIST(lazy_itable_init), 321 ATTR_LIST(batched_discard), 322 ATTR_LIST(meta_bg_resize), 323 #ifdef CONFIG_FS_ENCRYPTION 324 ATTR_LIST(encryption), 325 ATTR_LIST(test_dummy_encryption_v2), 326 #endif 327 #ifdef CONFIG_UNICODE 328 ATTR_LIST(casefold), 329 #endif 330 #ifdef CONFIG_FS_VERITY 331 ATTR_LIST(verity), 332 #endif 333 ATTR_LIST(metadata_csum_seed), 334 NULL, 335 }; 336 ATTRIBUTE_GROUPS(ext4_feat); 337 338 static void *calc_ptr(struct ext4_attr *a, struct ext4_sb_info *sbi) 339 { 340 switch (a->attr_ptr) { 341 case ptr_explicit: 342 return a->u.explicit_ptr; 343 case ptr_ext4_sb_info_offset: 344 return (void *) (((char *) sbi) + a->u.offset); 345 case ptr_ext4_super_block_offset: 346 return (void *) (((char *) sbi->s_es) + a->u.offset); 347 } 348 return NULL; 349 } 350 351 static ssize_t __print_tstamp(char *buf, __le32 lo, __u8 hi) 352 { 353 return snprintf(buf, PAGE_SIZE, "%lld\n", 354 ((time64_t)hi << 32) + le32_to_cpu(lo)); 355 } 356 357 #define print_tstamp(buf, es, tstamp) \ 358 __print_tstamp(buf, (es)->tstamp, (es)->tstamp ## _hi) 359 360 static ssize_t ext4_attr_show(struct kobject *kobj, 361 struct attribute *attr, char *buf) 362 { 363 struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info, 364 s_kobj); 365 struct ext4_attr *a = container_of(attr, struct ext4_attr, attr); 366 void *ptr = calc_ptr(a, sbi); 367 368 switch (a->attr_id) { 369 case attr_delayed_allocation_blocks: 370 return snprintf(buf, PAGE_SIZE, "%llu\n", 371 (s64) EXT4_C2B(sbi, 372 percpu_counter_sum(&sbi->s_dirtyclusters_counter))); 373 case attr_session_write_kbytes: 374 return session_write_kbytes_show(sbi, buf); 375 case attr_lifetime_write_kbytes: 376 return lifetime_write_kbytes_show(sbi, buf); 377 case attr_reserved_clusters: 378 return snprintf(buf, PAGE_SIZE, "%llu\n", 379 (unsigned long long) 380 atomic64_read(&sbi->s_resv_clusters)); 381 case attr_inode_readahead: 382 case attr_pointer_ui: 383 if (!ptr) 384 return 0; 385 if (a->attr_ptr == ptr_ext4_super_block_offset) 386 return snprintf(buf, PAGE_SIZE, "%u\n", 387 le32_to_cpup(ptr)); 388 else 389 return snprintf(buf, PAGE_SIZE, "%u\n", 390 *((unsigned int *) ptr)); 391 case attr_pointer_ul: 392 if (!ptr) 393 return 0; 394 return snprintf(buf, PAGE_SIZE, "%lu\n", 395 *((unsigned long *) ptr)); 396 case attr_pointer_u8: 397 if (!ptr) 398 return 0; 399 return snprintf(buf, PAGE_SIZE, "%u\n", 400 *((unsigned char *) ptr)); 401 case attr_pointer_u64: 402 if (!ptr) 403 return 0; 404 if (a->attr_ptr == ptr_ext4_super_block_offset) 405 return snprintf(buf, PAGE_SIZE, "%llu\n", 406 le64_to_cpup(ptr)); 407 else 408 return snprintf(buf, PAGE_SIZE, "%llu\n", 409 *((unsigned long long *) ptr)); 410 case attr_pointer_string: 411 if (!ptr) 412 return 0; 413 return snprintf(buf, PAGE_SIZE, "%.*s\n", a->attr_size, 414 (char *) ptr); 415 case attr_pointer_atomic: 416 if (!ptr) 417 return 0; 418 return snprintf(buf, PAGE_SIZE, "%d\n", 419 atomic_read((atomic_t *) ptr)); 420 case attr_feature: 421 return snprintf(buf, PAGE_SIZE, "supported\n"); 422 case attr_first_error_time: 423 return print_tstamp(buf, sbi->s_es, s_first_error_time); 424 case attr_last_error_time: 425 return print_tstamp(buf, sbi->s_es, s_last_error_time); 426 case attr_journal_task: 427 return journal_task_show(sbi, buf); 428 } 429 430 return 0; 431 } 432 433 static ssize_t ext4_attr_store(struct kobject *kobj, 434 struct attribute *attr, 435 const char *buf, size_t len) 436 { 437 struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info, 438 s_kobj); 439 struct ext4_attr *a = container_of(attr, struct ext4_attr, attr); 440 void *ptr = calc_ptr(a, sbi); 441 unsigned long t; 442 int ret; 443 444 switch (a->attr_id) { 445 case attr_reserved_clusters: 446 return reserved_clusters_store(sbi, buf, len); 447 case attr_pointer_ui: 448 if (!ptr) 449 return 0; 450 ret = kstrtoul(skip_spaces(buf), 0, &t); 451 if (ret) 452 return ret; 453 if (a->attr_ptr == ptr_ext4_super_block_offset) 454 *((__le32 *) ptr) = cpu_to_le32(t); 455 else 456 *((unsigned int *) ptr) = t; 457 return len; 458 case attr_pointer_ul: 459 if (!ptr) 460 return 0; 461 ret = kstrtoul(skip_spaces(buf), 0, &t); 462 if (ret) 463 return ret; 464 *((unsigned long *) ptr) = t; 465 return len; 466 case attr_inode_readahead: 467 return inode_readahead_blks_store(sbi, buf, len); 468 case attr_trigger_test_error: 469 return trigger_test_error(sbi, buf, len); 470 } 471 return 0; 472 } 473 474 static void ext4_sb_release(struct kobject *kobj) 475 { 476 struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info, 477 s_kobj); 478 complete(&sbi->s_kobj_unregister); 479 } 480 481 static const struct sysfs_ops ext4_attr_ops = { 482 .show = ext4_attr_show, 483 .store = ext4_attr_store, 484 }; 485 486 static struct kobj_type ext4_sb_ktype = { 487 .default_groups = ext4_groups, 488 .sysfs_ops = &ext4_attr_ops, 489 .release = ext4_sb_release, 490 }; 491 492 static struct kobj_type ext4_feat_ktype = { 493 .default_groups = ext4_feat_groups, 494 .sysfs_ops = &ext4_attr_ops, 495 .release = (void (*)(struct kobject *))kfree, 496 }; 497 498 static struct kobject *ext4_root; 499 500 static struct kobject *ext4_feat; 501 502 int ext4_register_sysfs(struct super_block *sb) 503 { 504 struct ext4_sb_info *sbi = EXT4_SB(sb); 505 int err; 506 507 init_completion(&sbi->s_kobj_unregister); 508 err = kobject_init_and_add(&sbi->s_kobj, &ext4_sb_ktype, ext4_root, 509 "%s", sb->s_id); 510 if (err) { 511 kobject_put(&sbi->s_kobj); 512 wait_for_completion(&sbi->s_kobj_unregister); 513 return err; 514 } 515 516 if (ext4_proc_root) 517 sbi->s_proc = proc_mkdir(sb->s_id, ext4_proc_root); 518 if (sbi->s_proc) { 519 proc_create_single_data("options", S_IRUGO, sbi->s_proc, 520 ext4_seq_options_show, sb); 521 proc_create_single_data("es_shrinker_info", S_IRUGO, 522 sbi->s_proc, ext4_seq_es_shrinker_info_show, 523 sb); 524 proc_create_single_data("fc_info", 0444, sbi->s_proc, 525 ext4_fc_info_show, sb); 526 proc_create_seq_data("mb_groups", S_IRUGO, sbi->s_proc, 527 &ext4_mb_seq_groups_ops, sb); 528 } 529 return 0; 530 } 531 532 void ext4_unregister_sysfs(struct super_block *sb) 533 { 534 struct ext4_sb_info *sbi = EXT4_SB(sb); 535 536 if (sbi->s_proc) 537 remove_proc_subtree(sb->s_id, ext4_proc_root); 538 kobject_del(&sbi->s_kobj); 539 } 540 541 int __init ext4_init_sysfs(void) 542 { 543 int ret; 544 545 ext4_root = kobject_create_and_add("ext4", fs_kobj); 546 if (!ext4_root) 547 return -ENOMEM; 548 549 ext4_feat = kzalloc(sizeof(*ext4_feat), GFP_KERNEL); 550 if (!ext4_feat) { 551 ret = -ENOMEM; 552 goto root_err; 553 } 554 555 ret = kobject_init_and_add(ext4_feat, &ext4_feat_ktype, 556 ext4_root, "features"); 557 if (ret) 558 goto feat_err; 559 560 ext4_proc_root = proc_mkdir(proc_dirname, NULL); 561 return ret; 562 563 feat_err: 564 kobject_put(ext4_feat); 565 ext4_feat = NULL; 566 root_err: 567 kobject_put(ext4_root); 568 ext4_root = NULL; 569 return ret; 570 } 571 572 void ext4_exit_sysfs(void) 573 { 574 kobject_put(ext4_feat); 575 ext4_feat = NULL; 576 kobject_put(ext4_root); 577 ext4_root = NULL; 578 remove_proc_entry(proc_dirname, NULL); 579 ext4_proc_root = NULL; 580 } 581 582